CA2656033A1 - Improvements in ink formulations comprising gallium naphthalocyanines - Google Patents

Abstract

There is provided an aqueous formulation comprising an IR-absorbing naphthalocyanine dye of formula (II): or a salt form thereof, wherein: M is Ga(A1); A1 is an axial ligand selected from -OH, halogen, -OR3, -OC(O)R4 or -O(CH2CH2O)eR6 wherein e is an integer from 2 to 10 and R6 is H, C1-8 alkyl or C(O)C1-8 alkyl; R1 and R2 may be the same or different and are selected from hydrogen or C1-2 alkoxy; R3 is selected from C1-2 alkyl, C5-I2 aryl, C5-12 arylalkyl or Si(Rx)(Ry)(Rz); R4 is selected from C1-12 alkyl, C5-12 aryl or C5-12 arylalkyl; and Rx, Ry and Rz may be the same or different and are selected from C1-12 alkyl, C5-12 aryl, C5-12 arylalkyl, C1-12 alkoxy, C1-12 aryloxy or C5-12 arylalkoxy. The formulation has a pH in the range of 3,5 to 7 and is particularly suitable for use as an IR- absorbing inkjet ink, providing compatibility with known CMYK, inks together with an optimally red-shifted .lambda.max

Description

RMOVEMEN'1'S jJi PiK FORIVUZATZOIV'S CO1V1pH~SING GALI.[CJM
NAF CY'ANINES
Fie[ n ve 'on Tho present application relates to infrared (TR) dyes, in particuRlar zim-IR
dyes, vv]xieh are synthetic,alJ.y aocessible in high yield and which are clispersible in an aqueous iulc base. It has been developed primarily for providing M inlrs compatible with CMXI{'. inks, and for optimizing IIR-absorptiou.

13ackround of the Tnvention IR absorbing dyes have numerous applie$tiotts, such aS qptical recording systams, thermal writing displays,laser filtdrs, infrared photography, medical applications and pt'i.utiug. Typically, it is deshmble for the dyes used in these applicatiom to have strong absorption ittt the uear-IR, at the emission wavelengths of semiconductor lasers (e.g. between qbout 700 and 2000 tun, preferably between about 700 and ] 000 nm). In optical recordiug technoaogy, for axample, =$allium alutniuium arsenide (CraAlAs) and indiuaa phosphide (InP) diode lasers are widely used as light sources.
Another importatt.t application of M dyes is in iuks, such as printing inks.
The storage and retrieval of digital infonnat'son in printed form is particularly important. A familiar example of this techuology is the use of pritued, scaquable bar codes.133ar codes are typically priuted outo tags or labols associated with a particular product aud contain iuformatiou about the product, 5uch as its identity, price etc. Bar codes are usually printed in lines of visible black ink, and detected using visible light from a scanner. The scanner typipally camprises aa T.P.D or lasar (e.g. aHeNe ]sser, wh.ich emits light at 633 nm) ligb.t source and a photoeell for detecting reflected liot. Black dyes suitable for use iu barocdo inks au'e describeri in, for L,c8ulple, W003/074613.
However, in other apprications of this technology (e.g, secutity tagging) it is desirable to h$ve a bas'oode, or other ipteIligible marking, printed with an ink that is invisible to the unaided aye, but which can be detected under UV or IlZ. ligbt.
An especially impcrtaut application of detectable invisible ink is in automatic identification systems, and especially "netpage' and "Hyperlabelllh" systems. Netpage systems are the subject of a number of patents and patent applications souu of which ares lisW in the czoss-zefexeuce section above and, sA of w#tich are incorporated herein by refereuce.

lu gEnentl, the netpage system relies on the production of, and human interaction with, netpages.
"fhesa $re pe,ges of text, graphies aq.d iUaages printed on ordinary paper, but which work lik.e interactive web pages. I.afomation is encoded on each page using ink which is substantially invisible to the unaided human eye. The ink, howaver, aud tber4by the codod dat$, can be sensed by an optically imaging pen and transmitted to the netpage system.
Active buttons and hyperlittk9 ou eae.h page may be clicked witli the pen to request inforn'Atiou from the network or to signal preferon.aes to awtraorlc server. In some fornns, text written by band on a netpage may be automatically recofinized and couvertad to cotnputer text in the netpage system, allowing forms to be filled in. In other fortus, signatures recorded on a uotpage rnay be $utorlrarlcally veri.fied, alIowiag e-commerce trapsactions to be securgly authorized.
Netpages are the foundatiqn on which a natpage network is built. They may provide a paper-based user ixGter.face to published informatiott aud intr.ractive services.
A netpa=ge cansists of a priuted page (or other surface region) invisibly tagged with references to an online desariptipn of the page. The online page desoriptian is maintained persistently by a ucstpage page sei'var. The page description describes the visible layout and conteu.t of the page, including text, graphics a.nd images. lt also descn'bes the input elements on the pagcs, including buttom, hyperlinlcs, and input fields. A
aetpage allows markiugs made with a netpage pen on its surface to be simultaneously captured and processed by the netpagd system.
Multiple netpages can share the same page description. However, to allow ipput through otherwise identical pages to be distinguished, each wtpago is assigned a unique page identifier. This page ID
has sufficient precision to distinguish between a very large numbex of TwtpAge&, Each rsferenCt to the page description is enooded in a printed tag. The tag identifies the uniquo page on which it appears, aod thereby irtdirectly identifies the page descriptiort. The tag also identifies its own position an tha page.
Tags are printed in infrared-absorptlve iuk on aby substrate whiGh is infrared-reflective, such as ordinary paper. Near-infrared wavelengths are iuvisible to the huum eye but are Gasily sensed by a solid-state ixaagc sensor with an appropriate filter.
A tag is sensed by an area itu&ge sensor in the netpage pett, aud the tag data is tt'au=[itted to the netpage system via the nearest netpage printer. The pen is wireless and comutunicates with the netpage printer via a sltort-range radio liltk. Tag9 ate suffieiently small and densely arranged that the pen can reliably image at least one tag even on a single click on the page. It is important that the pen recogruze the page ID
aMd positiou on every i teraction with the page, since the interaction is stateless. Tags are error-correctably encoded to make them psrtially tolerant to s-u'faoe damage.
The ttetpage page server maintains a un.ique page instance for each printed netpage, allowing it to maintain a clistiuot set of usnr-supplxed values for input fields in the page desoription for each printed netpage.
HyperlabelT s is a trade maTlc of Silverbrook R.esearch Pty L,td, Auatratia.
in gaueral, 'Hypexlabelr"' systacus use aa invisible (e.g. ittfrared) tag&g scheme to uniquely ideutify a product item. This 1o th-e significant advantage that it allows the entire surface of a product to be tagged, or a significant portion thereot without impinging on the gmpltic design of the product's packaging or labeling- If the entire surfaoe of a produGt is taggad ("omttitagged''), then the orientation of the product does not afFeqt its abiXity to be scanned i.e. a significant part of the line-of-sight disadvantage of visible barcodes is elimi.nated. Furtherrnore, if the tags arg compact and massively replicated ("omnitags"), then label damage no larige<' prevents scanning.
Tbus, hyporl.aboAing consi3tg of covarixGg a la.rge portion of the stu'Face of a product with optically-reudable i.ttvislble tags. When the tags utilize reflection ar absorptian iu the iufi'ared spectrum, they are refeired to as in&ared identification (1]M) tags. 1Jach HyperlabelTM tag uniqualy identifies tld product on which it appears. The tag may directly enopdo tbc pYbduct cedc of the atetn, or it may enoodo a surrdgata YT7 which in tutn identifies the product code via a database loolatp. Fach tag also optionally ideutiftes its own position on the surface of the product item, to provide the downstream consumer bcnefits of netpage iriteraCtivity.
HyporlabelsTm are applied during Product manufacture and/or packaging usiAg digital priaters, pref'ertibly ink,jei ptittwrs. These mAy bp add-on i~ecl printers, which print the tags after the text and graphics have bean printed by other meaRs, ot intesgrated colour and iafrared pri.nters whiekc print the tags, text aitd graphics simulmtteously.
HyperlabelsTM cazi be detected=using similar technology to barcodes, except using a light source having an appropriate near-IR freqqency, The light source tnay be a laser (e.g. a GaA.1As iflser, whieb epqirs kght at 830 nrn) or it ntay bd an LED.
From the foregoing, it wiit be readily apparetxt that'invisible Ilt detectabXo inks are an iraporGant component af netpage and HyperJabelTm systems. In order for an IR absorbing ink to fu.natiou satisfactorily in these systepls, it should ideally meet a number of criteria:
(i) compatibility of tbe IR dye widl traditional iul&t inks;
{ii) compaGtbili.ty of the IR dye with aqueous solvents used in inlcjet inks;
(iii) ilriteiise sbsorption in the near infr$-red region (e-g 700 to 1000 nm);
(iv) zero or low intensity visible absarpti4n;
(v) lightfastttess;
(vi) thermal stability;
(vii) zero or low toxicity;
(viii) low-cost manufaettt.re;
(ix) adheres well to paper and othet media; $nd (x) no sttiket3xt'ougkt attd minimal bleediug of the iulc on pritttiug, Hence, it would be desuable to develop TR dyes and ink compositions fulfiU.ing at least some and prefeunbly all of tlt above cxiteria. Such iul<S atc desit'able tn complement zu3tpage and HyperlabelT'4 systems.
Some 112 dyes are commercially available from various sources, such as Epolin Products, Avecia Inks and H.W. S=ds Corp.
In addition, the prior art describes various IR. dyes. US 5,460,646, for example, descrilavs an infrared pri.uixag ink comprising a coloraut, a vehicle amd a solvertt, wherein the colorant is a silicon (IV) 2,3-naphthalocyanine bis-triallcylsiiyloxido:
US 5,282,894 rlescXibes a soJvetxt-based pritatin ink comprisiqg a metal-free phthalocyar e, a complaxcd phthalocyxnine, a rnetal-fr= aapltthalacysninc, a eonaplexed naphthalocyanine, a nickel dithiolene, axi ami.ttitim cotnpound, a inethine compound or an aaalenesquaric acid.
Havwtvar, uom of tktese prior art dyes cart be fortuulated into ink compositions suitable for use in netpage or HyperlabelTm systGms. Li paTticular, Cotutuereially a'vaila.ble 4nd/or prior art iuks sumr from ozie =
ot more of the following probltms: absorption At wavolouAs unsuitable for detection by n0ar-1R seusors;
pQbr solubility ox.dispeXsibiUty in aqueaus solvent systems; or unacceptably high absorption in the visible part of the spectruiu.
In our earlier US patent application no. 10/986,402 (the contents of whieh is herein i;neorporated by reference), we described a water-soluble gallium. naphthalacya4ille dye fulfilli:pg uYany of the desirable properties identified above, ne dye typiaallY eowpxises four sulfonic acid groups, which irnW s higfY
degree ofwakesrsolubility, either in its acid or salt form. However, it ttas sitlae been -fotmd that the fomaation of salts using, for exstuple, sodiuin b.ydroxide or triethylamiue produces an unexpected btue-shift in the Q-band {~} of Gf1g dye, &om about 805 nm to about 790 nm or less. On the one lia.prl, salt formation is desirable because it .taisGs the pH of the dyn in solution maldng it compatible with other CMYK intcs.
Typically, CMYK inks have a pH in the range of S-9, so a strongly acidic IIt ink would potentially c& uae precipitation of ink components if the W, and CIvIS.'K inks are mixed on a printhead face dnt.ing purging. On tlte othor hand, blue-shifdug of the Q-band caused by salt foruultion makes these dyes less appealing as IR
iuk candidates, becsuse they must be used iu higher concentrations to liave aceeptalale deteetability by au iR.
sensor, resultang in the ink appearing xnore colored.
These contradictoty eeyuirements of the IR dye :qeed to be addressed in order to forsuula.te an 1R ink having opiirnzll perforatance in netpage ant]. Hyperlabeff appiicauons.

Summaxy of ttte Ynventien In a first aspect, there is prorrided an IR-absorbing napht.haleeyanine dye of formula (I);
+
SO3 RH* BH sos-qR2 Rl R
N
N\" ,/N Ri m~f N ' N
BH'' BH+
N
*,R Rz -a s sc~3 3 lRa wttereiu:
M is Ga(At);
A' is an axial ligand selected from-OH, halogem, -bR3, -L]C(O)124 bT
"O(CH2CH2O)0 wherein e is an integer from 2 to 10 and R` i$ H. C i.s a41 oX C(O)C i.s alkyl-;
It' gpc; It.z may be the same or different and are selected &om bydrogeri or C1.1z al.koxy, lt3 is selected from Cl:u alkyt, Cs-iz aryL Cs=-z aryl$lk5''l ot Si{It"}(R' }(R~;
1t4 is selected from Cl-i2 alkyl. Cs-iz aryl or Cs-t2 arylalkyt;
gx, p3' and Rz may be the same or different and are selected from Ci-ia Qlkyl, CS-i2 aryl. Cs-iz fflylau~yl> Ci-tz ,aUmxy, Cs-1a aryloxy or Gs-iz arylallcaxy; and S
each B is indepeadently selected from a base, wherein BW has a pKa of bgtween 4 azxd 9.
.A]ternatively, there is provided an aqueous formnlatioa comprising an Ilt-absorbing naphthalocyani.ne dye of formula (II);

B0aH $03H

:r,rN

Ri m R1 r~.
Nj R2 H03S..~ SO3hi / M-- R22 (II) Rt or a salt forn thereof, wherain:
M is Ga(A');
A' is an axial ligand selected from -OH, balogen, -OR3, -OC(O)W or -O(CHZCH2O),W wherein e i.s an iuteger froxn 2 to 10 anti R` is H, C1.6 atkyl or C((J)C14 a.lkyl;
Rl a.nd Rz may be the same or different and are selected from hydrQgen or Ci-I
z a]k.oxy;
R3 is selected frQm Ci-iz alk.j'], Cs-ix m7'1, Cs.i2 aryls]]cyX or Si(RNP-Y)(RZ), R4 is selected from Ci-ix alkyl, Cs-11ary] or Cs iz arylalkyl; and W, R'' aud Rz may be the same or different and are selected fwm Ci-12 a]]ryl, C$.G2 aryl, CS.13 arylaUcyl, Ci,12 alkoxY, Cs-iz aryloXy 4r C5-12 arylalk.pxy;
said fortrGwation having a pkT in the range of 3.5 to 7, In a second aspect, there is providad an inkjet u!k cotpprisittg a dye or a formulation as deseribed $bove.
In a third aspect, there is provided an inkjet printer comprising a printhead in fluid comrrtun-ication with at least one ink reservoir, wherein said at least one ink reservoir comprises an inlget ink as descri~ed above, In a fourth aspect, there is provided au ink aarGridge for an inlcjet printer, wherein said ink eartridge comprises a.p. :14kjet ink as described above.
In a fifth aspectt, there is provided 4 substrate having a dye as des4zzbed above disposed thereon.

Iu a sixth aspect, tktere is provided a method of eita$liug entry of data into a computer system via a printed form, the form co.utaiuin$ hutrtatl-readable inforptatiou and maclline-readable coded data, the oaded data being indicative of an ideritity of the form aud of a plurality of rocations ot1 the form, the methpd including the steps of:
S reeeiviug, in the computer system and from a sensin.g device, indicating d$m tegarding the ideatity of the fom and a position of the sensing device relative to the forut, the sensing device, when placed iu an operative position relative to the fortil, gonerdting tlw xtldioating data using at least some of th8 coded data;
ideutifying, in tiie coruputer system. aud from the indicating data, at least one fie3d of the fo=; arcd interpreting, in the computer system, at least some of the indicating data as it relates to the at least one field, whereiu sa.id coded dat9 comprises an 1'Ft.-ahsorbing dye as described above.
In a seventh aspect, there is provided a method of interacting with a product item, the product item having a pri.nted surface coutainiug hurnau-readable informatiop and machine-readable eoded data, the coded data being indicative of an identity of the product item, the method including the steps of (a) receiving, in the computct' systdm and from a sensing device, indicating data regarding the identity of the pr'oduct item, tbe sensing device, when plsced in an operative position relative to the product item, generating the indicating data using at le$st sorne of the coded data; and (b) identifying, in the computer system and using tlte indicating data, an interaction relating tfl the pxodpct item, wherein said coded data, couiptises an l.R-absorbiug dyt accnrdiug as described above.
Brief Description ofUrawinzs Figure 1 is a schematic of a the xelatiouship betwveep. a sample priuted uetpage and its ozrliue page description;
Figure 2 is a salu.uatic view af a iutdractiou bet'ou'een a petpage p84, a Wsb termi-nal, a notpaga printer, a netpage relay, a netpage page server, and a uetpage applica.tiou server, apd a Web server;
p'igure 3 illustxates a pollectiou of netpage servers, Web termimls, printers aud relays Warcouuocted via a uettivork;
Figure 4 is $ schematic view of a b.i.gh-levei structure Of a pr.inted itetpage and ite online page desosipticiu;
Figurc Sa is a plan view showins tha interleavutg su.d ratatiOU Of dxe symbols Of faur cQdervorda of the tag;
Figura .Sb i3 a ptan view showing a uxacrodot layout for the tag s#u7" in Figure 5a;
Figure Sc is a plan view showing an arrangement Of nine of the tags shown in Figures 5a and Sb, iu which targets 4re share.d between Aacent tags;
Figuro 54 is a plau view showiag a retationabip between a set of the tags shown in i:'igure 5a and a -fiekl of view of a netpage sensing d4vico in the form of a qetpage pen;
Figure 6 is a perspective view of a metpage pen and its associated tag-serasixig field-of-visW oorta;
Figure 7 is a porspoctivc ocplodad vitw afthe rtetp$gc pen sixown in p'igure 6;
Figut'e 8 is a schematic block diagratn Of a pen controller far thc uetpago pea shown in Figures 6 and. 7;

Figure 9 is a perspective view of a wall-mouated uetpage priutem Figure 10 is a section tluough the length of the netpage priutar of Figure 9;
Figure 10a is an enlarged portion of Figure 10 showing a section of the duplexed priut eugines atxd glue wheel assembly, Figura 11 is a detaileci view of the i.Ak cat'tritlge, inlc, air and glue paths, arzd print ongines of the netpage printer of P'igures 9 and 10;
Figiu'e 12 is an exploded view of an ink cairtridga;
Figure 13 is a schematic view of the struct7xee of an item ID;
Figure 14 is a schematic view of the strneture of ari oulriitag;
Figure 15 is a schematio view of a pen class ciiagram;
Figuzt 16 is a schematic view of the interaction between a ptoduGt iteni, a fixed product scatuyer, a hand-held product scanqsr, a scanner relay, a product server, and a praduct application servtr;
Figurc 17 is a perspective view of a bi-lithie printhead;
Figure 18 an exploded perspeetive view of the bi-lithic prinihead of.Pigu:re 17;
Figure 19 is a sectional view througb ope ettd of tbe bi-lithic prufthead of Figure 17;
fture 20 is a iougitudiual sectioqal vicw through the bi-lithic printhead of Figure 17;
Figures 21(a) to 21(d) show a side elevation, plan view, opposite side elevation and reverse plan view, respeet.ively, of the bi-lithic priuthead of Figure 17;
Figfues 22(a) to 22(c) show the basic operatianAlprizciples of a tlusnual l:"ad actuator;
Figure 23 shows a three ditnensionai view of a single ink jex nozz1G
arrangement constructed in accordance wit.h. Figure 22;
Figure 24 shows an array oftile uozzla arrangements shown in P'igure 23;
Figtu'a 25 is a scb.ematic cross-sectioral view through an ink chamber of a unit cell of a bubbla fonxung heater element actuator;
Figure 26 shows a refiectance spectrum of hydrox.ygailiusn naphthalocyaniuGtetrasulfoqio acid 4;
.Figure 27 shows $'I-I NMIt. spectrum of hydraxygalliu.m naphthalocyaninctetrasulfonio aoid 4 isi ds-DMSO (0.1% w/v);
p'igure 28 shows a reflectance spectrum of tetraimidazoliucn hydroxygalliuur naphthalocyaninetetrasulfonato 7;
Pigure 29 shows a reflectance spectrum of tetralcis(DBUatuznonium) hydroxygallium uaphthalocyaninntctrasulfonate 9;
Figure 30 shows a reflectance spectrum of telrakis(D13Uammouit3~p) hydroxygallium ttaphtbalocyauinetetrasulfonate 9 with.p-toluenesulfonic acid (3 equivalents);
Figure 31 shows a.refleatapce . spaccrutp of te(rai:cnidazoliutn hydroxygallium naphthalocyaninetetrasulfonates 7 with two equi'vul.eats of acetic 4cid.

T?etailed TDe,cription IR-Ahsnrbfnq L)ye As used herein, the term "1K-absort5ing dyc" means a dye substance, which absorbs infrared radiation and which is therefore suita6le for detection by an infrared senstar. Preferably, tlw I.R absorbing dye absotfis in the near in.fra.red region, gmd preferably has a~,,~ in the rdri.ge of 700 to 1000 nrn, more preferably 750 to 900 nm, more preferably 780 to 850 iuu. Dyes having aX,,, in this range are particularly suitable for detection by semiconductor lasers, such as a gallium aluminium arsenide diode 1ops, or.
As will be explained in more detail below, dyes representEd by formula (1) may be in equilibrium 'vvith other tautouaars in which rneso-nitsogen(s) of the napbthalocyanine ring system are protonated. l3dood, the dye represented by formula (I) r.nay only be a miuor species in this equilibriurxt. However, by convention, dyes according to the present invention are generally represented by fortuuls (I). Other tautomers in equilibrium therewittt are, of course, included wathiU the scope of the present inventioq.
Dyes according to the present itiveution have the advantageous features of:
optimal Qbsorption in the near-1R region; suitability for formt=lafiiott into aqueous iukjet inlcs; pH
compa,tible with known CMYK inks without saerificizlg optimal near-IR absarption; and facile preparation.
Moreover, their higlx extiaatioti coeiilcien.ts in the near-IR region means that the dyes appear "invisible" at a Concentratio4 suitable for detection by a ndar-.1R, detector (e.g. a iletpage pen). Accordingly, the dyes of the prasent invention are especially suitable for use in rtetpsge and HyperlabelTM applibations. None of the dyes lmown in the ptior art has this unique combinution of properties.
'(be prGsent invention was itxil'.iAlly cotaceived by observing the reacticra of a galliuin naphthalocyanine tet.r$stttfanic aoid salt with four equivalents of am.ine to given an amsnonium salt. It was found, surprisingly, that the reflectance spectra of amnxoniuin salts are independent of tbe struoAut of the ap~ibut very tuuch affectcd by thcc pI4, oftho auunonium salt. At low p& the Q-band (Xu) has a large nanuoxneric component and is red-shifted to 800-810 nm. However, when strongly basic amulas aro used, the Q-band exhibits a signi$cant dimer or aggrepte compoAeut aud tbe lttorton~t.comppnent is blue sh-iftvd to <800 um. Given that the itttcml mesp uitrogans of ttte naphtbalt+cyanine ring system have p1Ce values of about 11.5 (first protonation) and 6.7 (second protonadorY), then without wishi.og to be bound by theory, these results have been intcrpretcd in terms oftht abiGty of the arnmonium ion to protonate zero (structure A), one (strncure 8) or two (structure C) of the meso tutrogens. The greater the protonating ability of the ammouium iott (lower pKa), the gieatar tbe deg'ee of protonation of the tnacrocycle. It is believed that protonation of tha macrocycle reduces 7[-,z stacicing between adjacent molecules by electrostatic repulsion. With less aggregation and a grgater mouotxter comporierit, a red-shift of the Q-baqd of the Wt is observed.

BrPoo~s ao~g ~ oO~ ~ ~
n r! e- N w C
N N
N~OHI ~4N1 N N~
so, J N N aQ N N So~
~ V ri aHd r h~
so~b so, ~ so,d = BH@ Bb&sea,O. Wt111ri PH~
A S c Foliowing on from these surprising results, it was then fuund that ather wea.k aaids could effect the same phenomena. For exatnple, tieatiilg the tatrasuEfonic acid with four eauivalents of lithium or sodium acetate (B = AcQ') gave aharaattrsstie red-shifted $pectm resulting from t$e formation of the lithium or sodiusn salt anst four equivalents of $eetic aeid. It was therefore concludod tltat the pfI of the sotutiou (controlled by tha pg. of the liH' species) is the most important factor in controlling the red-shiiW
behaviour of certain uaphtlialocyaui.ua dyes.
With pH identifxad as the key factor controlling 1,,,, it follows tltat suitable IR ink formuladons may be prepared by dissolving a naphthalocyaninetetr$sulfouic acid in an ink vehicle and ad,jpstirrg the pH of the resulting formulation. It has been fnuud that formulations having a pH
within the mge of 3.5 to 7, or opxiopally 4 to 6.5; are desirable for 8cltie'ving a red-shified Q-band wbile ma.intaÃuing CMYK compatibility.
The pH may be adjusted using auy suitable base (e.g. the conjugate bases of kIe weak acids descrtlaad below) or using a buffer solution.
It is expected that the sabpe phenomenon may be sirailarly used in controlliug Q-band absorption for a whole range of sulfonated phthalocyanine and nsphthal4oyanine dyes. The usa of pH to fuxe-tuae Q-band absorption has not been expIoited previously and rapresents a convenient, low cost approach to producing red-shifted .IR. dyes. Specific examples of dyes and fotxqulatipns oxploiting t'1s pheuomeuan are provided below in the Fxamples.
The species HH+ iu the present invention is a weak acid having a pIC., in the range of 4 to 9, or optionally 4.5 to S. The dyes of fornaul$ (Y) r.tray be readily for.mvd by the addition of a base to the corresponding tetrasulfonic atcid. Tha basa H rnay be ueutral (e.g. pyridine), in which case 13W wiu be overall positively clArged (e.g. C6H,-,NH''). Altcrnatively, the base may be anionic (e.g. acetate aqiotx) iza which case ]3H" wi.ll bc overall neutral (e.g. AcOH). Iq the case of any or all of BW heisrg ueutral, the ovcrall ucutrality of the naphiltaiocyauuus salt is maiutainvd by a suitable numbor ofnacta.I caunterions (e.g. I-i", Na"
elc).
'f'ha skilled pmon nvill be well aware of a wide variety of wealc acids, which fulfil the criteria of the preaent invention. Some examples of common acids having a pKõ in the range of 4 to 9 are pr4vided below.
In accordance with coiivention, the py,, of some ac=ids 4re referred to by their corresponding conjugate base.
For oxaiuple, the pK, of pyriuline refers ta the pK, of the correspouding pyridWu$n ion.
AG4tiG aCid 4.76 Etliyleneimine 8101 1 H-Imidazola 6.95 2-Thiazolamine 5,36 Aorylic acid 4.25 Melamine 5.00 Propanoic acid 4.86 3-Hydroxypropanoic acid 4.51 Trimethylamine oxide 4.65 Barbitaric acid 4.01 Alloxanic acid 6.64 I -McthyLiraidazole 6.95 Allantain $.96 3-13tttettoic acid 4.34 tratrs-Crotonic acid 4.69 3-Chlorobutancic acid 4=05 4-Cltloro'Dutmoic acid 4.52 Butanoic a.cid 4,$3 2-14tetktyTpropanoic aaid 4.88 3 Fiydroxybulanoic acid 4.70 5 4-Hydroxybutanoic acid 4.72 Morpholiire 8.33 Pyridiue 5.25 2-Pyridim~ 6.82 2,5-X''yriclinccliamine 6.48 10 2,4-Dimethylixzidaz41e 8.36 Methylsuccinic acid 4.13 Fiistarnine 6.04 ; 9.75 2-MethylbutauoiG acid 4,80 3-Methylbutauoic acid 4.77 15 Ptrntanoic acid 4.84 Trunethylacetic acid 5.03 2,34iChlorophenol 7.44 3,6-Dini.trophenol 5.15 Pteai.dirie 4.05 20 2-Chloropbepol 8.49 3-Chloraphenol 8185 3-1'yridimcatbox.ylic acid 4.$5 4-Pyridinecarlaoxylic acid 4.96 2-Ni.teaphetroX 7.17 3l3iiropbewl 8.28 4 Nirrophenol 7.15 4-Gltlora4uiliue 4=15 4-Fiuoroauiline 4.65 A.O%]ine 4.63 2-IV,lethylpyridine 5.97 3-lvlethylpyri.dioe 5.68 4-Metbyipyridime 6.02 Mothaxypyritl.iue 6.47 4,6-Aimethylpy6nidin=ine 4.82 3-IvXethylgltttaxic acid 4.24 Adipamic acid 4.63 Hexanoic acid 4.85 4-Metlyylperxianoic acid 4.84 Barurirnida.zokc 5.53 Befwic acid 4.19 3,5-Mydroxyhenzoic acid 4.04 ~t Gallic acid 4.41 3-Aminob=oic acid 4.78 2,3-X]imethylpyridine 6.57 2,4-Dimethytpyridine 6.99 2,5-Dimathylpyridine 6.40 2,6-Aimethylpyridiuo 6.65 3,4-D,imethylpyridine 6.46 3,5-pim.ethylpyridiue 6.15 2-Ethylpyridsne 5.89 N-Met$tylani,line 4.84 o-Methylaniline 4.44 m-Methylanillpe 4.73 p-1Vleiitylauxiline 5.08 c-.Anisidine 4.52 m-Auisidint 4.23 p-Anisidine 5,34 4-Methylthioauilia~ 4.35 Cyclohexanecarboxylic acid 4.90 Heptanoio acid 4.89 2-Methylbeazimidazole 6.19 Pilenylacetic acid 4.28 2-(Methyl4mino)benzoic acid 5.34 3-(Methylamino)benzoio acid 5.10 4-(Methylamino)benzoic acid 5.04 N,N-Aixnatb.ylutilius 5.15 N-Ethylaniline 5.12 2,4,6-rriruethylpyiidine 7.43 o-Pltenetidiua 4.43 Yn-Phenetidine 4.18 p-1'hwetidine 5.20 veranz]. 7.43 Qctazusdioio aoid 4.52 Octamic acid 4.89 v-GhloroGinnqmuc acul 4=23 m-Chlorocinnamic acid 4.29 p-Cblotocipnaniic acid 4.41 Isoquinoline $=42 Qui oliue 4.9Q

7-lsoquaualinol 5.58 1-Isoquiuolinamine 7.59 3-Qtunalinamine 4,91 trans-Cinuamic acid 4.44 2-Ethylbcuzimid.3zole 6.18 Mesitylenic acid 4.32 N-Allyiaqil%ne 4.17 Ty'tosineamide 7.33 Nonanic acid 4.96 2-Methylquinoline 5.83 4-Methylquinol.ine 5.67 5-Mgthyiquinoline 5.20 6-Methoxyqitin.oline 5.03 o-Metbylcinnainic acid 4.50 m-Methylcinnamic acid 4.44 p-Mgthylcinuamic acid 4.56 4-Phenylbutsnoic acid 4.76 N,N-Diethylaniline 6.61 Perimidine 6.35 2-Naphthoic acid 4.17 Pilocarpine 6.87 1,10-Phenantluolina 4.84 2-T3eazylpyridinc 5.13 Acridine 5.58 P4azwnthradiAe 5.58 Morphine $.21.
Codeine 8.21 Papaveriuc 6.40 Strychnine 8.26 Bruoiue 8.28 It will, of course, be appreciatcd that the present invention is not limited to those acids listdd above and the skilied persou wj11. be readiEy able to select other acids (or aoTjttgate bases) having a pK. in the range of 4 to 9, or optioually 5 to 8.
OptiorAily, each B is indepepdently selected &ram the grbup consisti-ng of a nitrogen base and an oxyanion. Accordingly, each B may be a nitrogen base. Alternatively, e$ch B
may be an oxyanion base.
AltLrrzatiwefy, there may be a mixture of nitrogen and ox.yauion bases in one dye salt. f or example, the four BH' molecules way consist of two tnolecules of acetio acid and two pyriduuunx ions, ar alternatively one molecule of acttic aud three imidaaolitta ions. The skilled person will bc readily able to conceive of a variety of .tnixed dye salts witktin the atttbit of the present invention.
By "nitrogen base ' it is [nea.rtt a base containing at least ous nitrogen atom, wliiah can be protonated. Optionally, the nitrbgen ba?e is 4 C5.t2heteroaryl base, such as um.id=)ie or pyridine. Imidazole is a patxioulafly preferred base in the present invcutiou.

By "oxyattipn" it is meaAt a base cQntain.ing at least one oxyanion, which can be protot>Med, Qptionally, the Qxyyauicn b$se is a carboxylaRs base, A carboxylate base is an organie molecule comprisirag at Ieast one carboxyl$te (COZ ) moiety. OptxOna1lY, the carbaxylate base is of formula RsC(Q)O-, wherein RS is selected fraru Ct-t2 alkyl, Cs.1s aryi or Cs-ta arylatlcyl. Examples of carboxylate bases include acetate, S benzoate etc.
The groups rcpresented by RI and RZ m$y be used for modifying or "tu.nin.g"
ibe wavelength of X,, ofthC dye. Eleetron-donating substitueuts (e_g, alkoxy) at the ortbo positions can produce a recl-shift in the dye. In one proferred embodiment of the present invetltion, R' zu-d A2 are both Cl-e aAcoxy groups, preferably butaxy. Butoxy substituents advatltageously shift the k,,,u towards longer wsveleugths in the ttear infrared, I{l which are preferabZe for detection by couuuerciall y available lasers, In another preferrod embodimeut Rl antl lta are both liydrogen, which pz'ovidos an expeditious ayA.thcsis of the reqtzisite naphthalooyattines.
The cent-4l metal atoxnU has been found, stuprisingly, to have avary significant impact on tI[e light stability of the compouaxds of the prescnt invention. Previously, it was believed tbAt the rsature ofthe orgatlic tmphtl~alt+cyaniuc chromophore was prlruarily responsible for the tato at w#dch such compounds 15 degrade. Plowever, it has now baeu found that certain meta!
naphGha.tocyani.ws show unusually high light stability compared to other metals. Specifxcally, gaAiruu attd eoppar naphthalocyanines have been ahown to exhibit very good light stability, nqakaag tbese eoinpotuYds higlily suitable for uetpage and >:Syperlabelt"4 applications in which the IR dye may be exposed to off'icp lightiug or sunlight for a year or more. Cra.lliutn compounds are particularly preferred since these have a more red-s3iifted 4m eomp=d to copper. A more 2(l red-shi#ted X., is preferred, because colored cyan dyes are less likely to iAterfere wit3t the IR dye's respotyse to the netme pen.
Typically A' is a hydroxyl graup (-C1H). Alterauti'valy, At may bc selected or modi&ed to irnpart specific properties onto the dye molecule. At may bt scelact.ed to add uxial steric bqlk to the dya uole"otale, thereby reducing eofaeial intsraetions between ad.jacent dye ueolecules.
25 Qptionally, the axial ligand, when present, adopts a conformation (or is configured) such that it dffectively "pCotccts" or blocies s n-face of the dye molecuae. An axialligand, which catz form an "umbrella"
over the -n-systom and reduce coi'acial interactions between ad,jacent dye molecules is particudurly suitable fbr use in tlie present invention, It bas bcsn reoognized by the presen.t inventors that IR.-absorbing dye compounds of the prior art 30 absorb, at least to sosne extent, in the visible region of the spectnun.
Indeed, the vast mAjority of Ilt-absorbiug dye compounds known iu the prior ar6 a,re blaalc or green or brown hues of black in the solid state.
This visible absorptian is clearly undeSirabie ip. "invisible" .U2. inks, especially M iui<s for etse in petMe or HyperlabelTM systems.
It has furtlier been recognized by the present inventors that the presence of visible bands in the 35 absorption spectra of1R-absorbiztg dye cotnpounds, and particularly IR-absorbing meW-ligand complexes, is at least in part due to cofacial interactions between 4acent molecules.
Typically, IR-absorbinp compounds comprise ait-system whiclt forrms a substantially plaaar moiety in at least part of the molecule, There is a naturAl tesndcsucy for planax 71-systeiris in $djacent molecules to stuclC on top of each other via cofacial rt-intersctiorts, kttawn as n-n stacking. Hence, IR-absorbing 40 compoeulds have a natural teridetloy to group together via cofacial 1c-iuteraCtiobs, producing relat'tvely wealcly bound dimers, triniers etc. Without wishing to be bound by theory, it is understood by the present inventors that n-tt stacking of73t-&bsorbing compounds oontributes sigpzficantly to the production of visible absorption bands in theit I12. spectra, which would not otheswise be present in the corresponding zn<+nomerie compounds. This visible absorption is understood to be due to broadening of AZ
absorption bands when n-systems stack on top of each other and n-orbitals iut.eraet, producing small changes in tlxeir respective energy levels. aroadening of 1R absorption bap.ds is undesirable in two respects;
firstly, it reduces the iatensity of absorption in the Izt region; secondly, the 1R 8bsorption band tands to tail into the visible region, procluoiug highly coloured compounds.
Furtherrqare, the formation of ooloured dimers, trimers etc, vip n-n interactions occurs both irL the solid state and in solufion, However, it is a partieuiar prablem in the solid state, where tbarB are no solvent molecules to clistvpt the formation of extenderi n-staeked oligomers.llZ dyes having acceptable solution cl.iat'actettitistics may still be intensely coloured solids when printed outo paper. The ideal "utvisible" IR dye should rerrtain invisible when the solvent has evaporated or wicked itrto the paper.
Dendrimers, for example, are useful for exerGug maximum steric rapulsian since they have a plurality of bxa.nched chains, such as polymoric chains. However, it will be appreciated &om the above that Any moiety or group that can i.uter"fore aufficiently with the cofaeial g-n int.eractioAS of adjacectt dye molecules will ba suitable tbr minimiaing visible absorption.
Alteruatively (or in addition), A' may be selected to add further hydrophilicity to tbc dye molecule to increase its water-dispars?.faility.
Generally, the naphthalocyanine dyes accordiag to the present invention are synthesized via a cascaded coupl'uig of four 2,3-dicyanonapthaleuE (1) molecules, although they may also be prepared from the corresponding 1-am.ino-3-iminoisoindolene (2).
NH
cN

I I N
CN

f 1} (2) NH2 The cascaded base-catalyscsrl macrocyclisation may be facilitated by metal templating, or it may proceed i.n the absence of a metal. If macrocylisation is performed in the abseuce of a teYnplating metal, then a met$1 rnay be read.il.y imserted into the resultant metal-free napthalocyanines. Subsequent sulfonation and salt farmation proceed by standard procedures. Further synthetle details are provided below in the Examples.
The tarm "hydrooarbyl" is used ]tereiii to refer to monovalent groups consisting generally of carbon arrd hydxogeri. Hycirocarbyl groups thus include alkyl, alkenyl and alkynyl groups (in both straight and branched chain forms), carbocyclic groups (including polycycloalkyl groups such as bicyclooctyl and adamantyl) and aryl groups, and combinations of tbn foregtiing, such as alkylcycloalkyl, alkylpolycycloalleyl, alkyiaryl, allcenylaiyl, alkynylaryl, cycloalkylaryl and cycloalkenylaryl groups. Similarly, tho term "hydrocarbylene" refers to divalent groups corresponding to the monovalenc hydrocarbyl groups descn~bed above.

LTAless specifically stated othenvise, up to foui -C-C- and/or -C-H moieties iu the hydrocarbyl group may be optionaliy interrupted by one or more moieties selected &xrrn --Q-; -N12.-; -S--; -C(O)-;
--C(0)0--; -C(O)NR"-; -SO2--; -SO20-; -SQ2NR'"-; wltcre TZ" is agroup selected froM H, Ci.12 a1ky1, Cs.iz aryl or C&12 arylalkyl.
5 Unless specific$(ly stated otherwise, where the hydrocarbyl group Canmim one or more TC---C-moieties, up to four--C=C- moieties may optionally be replaced by Hence, the term "hydrocarbyl"
may include moieties such as hateroaryl, ether, tbioether, carboxy, hydroxyl, alkoxy, amine, tkdol, amide, ester, ketone, sulfoxi.de, sulfonate, sulfouauiide etc.
Unless specifioally stated otherwise, the hydrocsrhyl group rnay comprise up to four substituents 10 independently selected from halogen, cyan.o, uitro, a hydrophi-lic group as defsned above (e.g. -SO39, -SOX -C(]zNa, -NH3'", NMe3' eetc.) or a polymeria group as defined above (e.g.
a polymeric group derived from polyethylene glycoi).
The terxn. "aryl" is used herein to refer to an aromatic group, such as phenyl, naphtklyl or triptycenyl.
C6-,2 aryl, for example, refers tv an arouaatic group having fzom 6 to 12 carbon atoxns, excludiug any 15 substituents. The term "arylerae", of course, ref+grs to divalent groups corresponding to the monovalerxt aryl groups descrÃbed above. Auy refnreuce to at'yl implicitly inc113des arylene, wherc appropriate.
The term "heteroary]" refers to an atyl group, where 1, 2, 3 or 4 carbon atcms are repla,ced by a heteroatom selectOd froin N, 0 or S. EExaiuples of heteroaryl (or hataroaromaGic) groups include pyridyl, benzizriidazolyl, indazolyl, quinolinyl, isoquinalinyl, iudoliuyl, isoindolinyl, uulolyl, isoiudolyl, furanyl, thiophenyl, pyrrolyl, tiuazoly], itnidazolyl, oxa.zolyl, isoxazolyl, pyra:eolyl, isoxazolonyl, piperazinyl, psnymidinyl,,piperidinyJ, maxpholinyl, pyrrolidinyl, isotlxiazolyl,lxiazolyl, oxadi&zolyt, thiadiaxolyl, pyridyl, pyrixnidinyl, be.pzopyrimidinyl, benxotriaaole, quinoxalinyl, pyridazyl, coumarinyl etc. The tert3t "heteroarylene", of course, xefen to divalent groups corresponding to the mouovalcnt heteroaryl groups descrilyed above. Any referenGe to hsrei'oasyl implicitly includes leteroarylen.e, where appropriate.
TJnless specifcally stated otherwise, aryl, arylejac, heteroaryl and heteroarylene groups pn$y be optionally substituted with 1, 2, 3, 4 or 5 of t1he substituents d.csoribetl below.
Where reference is made to optiorl&.l1y substituted groups (e.g. in conuection with bridged cyclic groups, aryl groups or lheteroaryl groups), the optional substitAeiXt(s) are b.idependently selected from CI.s alkyl, C,-s alkoxy, -(OCHzCHz)d0Rd (wherein 4 is an itxteger frorn 2 to 5000 and Rd is Ii, Ci.a allcyl or C(G)Ci-8 alkyl), cyano, halogen, amino, hydroxyl, thial, -SR", NRR'', nitro, phenyl, phenoxy, -CQZR", -C(O)R", -OCQR", -SO2R", -OSO,R ; -S")2`, NRC(O)R , -CONR"R'', -CQNR"R , -SQzI+1R."R'', wherein W aud R" ai'a iudependetttly seleeted fiom hydragen, Ci-12 alkyl,.phenYl ar phenyl-C).e alkyl (e.g.
benzyl)_ Whera, for example, a group cotxtains tnore than one substituent, different substituauts cau lave di#fermt W or W groups. For example, a n4phthyl group may be substituted with three substituen.tar -SOzNHPh, -CO2Me group and -NH2.
The term "alk-yl" is used het'eiu to refer to alkyl groups in both straight and branched forms, 'T'he alkyl graup zAay be intemtpted with 1, 2 or 3 heteroatoms selected, from. 0, N
or S. The alkyl group may also be interrupted with 1, 2 or 3 double and/or triple bonds. However, the terrn "allcyl" usually refers to alkyl groups havFUg no heteroatbm interraptions o1' dotable or triple bor-d 'u-terruptions. Where "allcenyl" groups are specifically merltiotted, th.is is not Irttended to be construed as a limitaion on the definition of"allcyl" above.

The term "alkylõ also iilcludes halogenoalkyl graups. A C1.12 alkyl group ntay, for example, have up to S hydrogen &toms replaced by halogen atotn3.Por example, the group --OC(O)C1-7z aik,yl speoi.fically iu4ludes -0C(Q)CF3.
Where refsreuce is made to, for example, Cl.is alkyl, it is meant the alkyl group may contain any number of carbou atoms between 1 and 12. Unless speeifically stated otlxerwise, any reference to "alky]"
r.neans C1-12 alkyl, praferably Cl.s alkyl.
The term "alkyl" also ixteludes cycloalkyl groups. As used herein, the term "cycloalb~yl" includes cycloalkyl, .polyoycloalkyl, and cycloalk.artyl gt'oups, as weU &s combinations of these with lutesar aUcyl groups, such as cycloallcy'lalkyl groups. Tho cycloal]cyl group may be intcrt'uptecd with 1, 2 or 3 hetdroatoms selected from 0, N or S. However, the term "cycloalkyl ' usua.lly refers tp oyclo&llcyl groups having no beteroatom interruptions. &xamples of cycloalkyl groups inClude cyclopentyl, cyctohoxy], cyclohexenyl, oyclob.exylmethyl and adatuantyi groups.
The terrn "arylalkyl" refers to groups suoh as bettzyl, phenylethyl and naphthy.lmethyl, 'I'he term "ltalogeu" or "halo" is used herein to refer to any of #luorine, chlorine, broulim and iodine.
bTsually, however, halogen refars to chlorine or fluoriua substituents.
Where reference is made to "a substituent oomptising ... " (e.g. "a substituept comprising a hydrophilic group", "a substituent com.prisixtg a.u acid group (unoludiug salts thereofj", "a substituent comprising a polymeric chain" etc.), the substituent in question may consist antirely or partially of the group specified. For example, "a subst3tuent comprising att acid group (irtaludistg salts thereof)" may be of formula --(CHJ, Sta3K., whereina is 0 or an integer from 1 to 6. Hence, in this coutext, the term "subsrituent" may be, for exaraple, an alicYl group, which has a specified group attach:ed. However, it will be readily appreciated that the exact aature of the substituent is not crucial to the des,ired fuctctions=lity, provided that the specified group is ptv,--a Cbiral compounds desen'$ed herein have not beeu given stereo-descript.ars.
Howover, when cou.igouuds may exist in stereoisQUwric forms, then all possible stemoisoruers and mixtures thereof are included (e.g. tnankiomers, diastereomers and all ooi biuations including racemic rp.ix.tut'as etc.).
Likewise, when compounds may exist in a number bfrcgioisoineric farms, then all possible regioisomtrs and mixtures thereof are included.
For the avoidance of doubt, the term ` aG" (or "aq"), in phrases such as "comprising a", mealls "at least one". and not "one and only ane"_ VVhertl the tenn "at least one" is specifcally used, thfs should not be constmr.d as having a limitation on the definition of "a".
Throughout the specification, the term "comprising", or variations such as "comprise" or "comprises", should be construed as inoludizYg a stated element, integer or step, but not excluding any other alement integer or step.

I Pr Inl~c The present invention also provides an iucjat tiak. Preferably, the in.kjet ink is a water-based iulcjet inlc.

Water-based ink.jet iak coMpositions are well known ia the literature and, in addition to water, may comprise additives, such as co-solvesats, biocides, sequestering agents, humeetants, viscosity modifiers, penetrants, wetGing agents, su.rfactants etc.
Co-solvents are typically water-soluble organi4 solvents. Suitable water-solubla organic solvents include Cl.4 allcyl alcohols, suah as cthapol, methanol, butanol, propanol, and 2-propanol; glyeol ethers, such as ethylene glycol a3ottoanethyl ether, ethylene glycol monoethyl et'her, ethylene glycol monobutyl ether, etltylene glycol monomethyl ether acetate, diethyl8se glycol monomethyl Cther, diethylene glycol monoethyl ether, diethylene glycol mono-n-prapyl ather, ethylene glyoal rnouo.isopropyl ether, diethylene glycol mono-isopropyl et75er, ethylene glycollnono-n-butyl ether, diethylene glycol rnauo-p,butyl ether, trieth.yiene glycol mono-n-butyl ether, etlzylene glycol mono-t-butyl ether, diethylene glycol mono-t-butyl ether, 1-methyl-1-ruethoxybutanol, pr+apylene glyool monomethyl etfibr, propylene glycol monoethyl ether, pro.pylene glycol uwuo-t-butyl ather, propyleue glycol uxorto-n.-propyl ethor, propylene glycol mono-isopropyl ether, dipropylena glycol monomethyl etbcr, dipxopylene glycol monoethyl ether, dipropylenc glycol mono-n-propyl etiler, dipropylacw glycol mopo-isopropyl ether, propylene glycol mono-n-butyl ether, and dipropylene glycol mon0-n-butyl ether; forrpamida, aectamide, dimethyl Sn1fb7C1C1$, sorbltol, sorbitan, glycerol mowacetate, glycerol diaootat0, glycerol triacetate, and st}1.fojane;
or combinations tkldreof Other useful Water-saluble organic solvents include polar solvents, such as 2-pyrrolidone, N-methylpyrrolidone, a-caprolactam, dimethyl sulfoxide, sulfolme, morpholine, N-eth.ylmarpholine, 1,3-dimethyl-2-iuxidazolidinone and combinations tbereoP.
The inlcjet ink may contain a high-boiling water-saluble organic solvent which can serve as a wetting agent ar 11utt1ectaut for imparting water retentivity and wetting pr4peities to the ink composition-Such a high-boiling water-soluble organic solvent includes oue having a boiling point of 3.80 C or htglier.
Examplas of the water-soluble organic solvent having a boiling point of 1809C
or higher are ethylene glycol, propylene glycol, diethylene glyml, pentamethylene glycol, trinzathylerte glycol, 2-butene-1 ,4-diol, 2-etlt.yl-1,3-hexanediol, 2-methyl-24-pentanediol, tripropylene glycol monomethyl tluor, dipropylene glycol rp.ouoethyl glycoi, dipropylene glycol monoethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol, triethylena glycol monomethyl ether, tetraethylene glycol, triethylene glycol, diethylerie glycol mou.obutyl ether, diethylene glycol monoethyl ether, diethylene glyeol uu7nouxetb.yl ether, tripropylene glycol, polyethylene glycols having inolecu.lar'oveig]zts of 2000 or lower, 1,3-propylene glyG4l, isopropyleue glycol, isobutylene glycol, 1,4-butanediol, 1,3-butame4iol, 1,5-pentauediol, 1,6-hexanediol, glyceral, arytlritol, pentaerytliritol and combinations thereof.
The total water-soluble organic solvent content in the inlcjet ink is preferably about S to 5Q% by weight, more preferably 10 to 30% by weight, based ot3 ft total ink composition.
Otber suitable wetting agents or humdctantg include sacobarides (including xuonosaccharidea, oligosaccharides and polysaccharides) and derivatives thereof (e.g, maltitol, sorbitol, xylitai, hyalurortic salts, aldonic acids, uronic acids e1e.) The iulcjet ink may also contain a perce#rant for accelerating penetration of the aqueous ink into the recording mediusu. Suitable penetrauts include palyhysiric alcohol alkyl ethers (glycol ethers) and/or 1,2-a4ldiols. F-xaruples of suitable polyhydt'ic alcollol alkyl ethers ara ethylene glycol momsnethyl ether, ethylene glycol mopoetbyl ether, ethylene glyaal monobutyl ether, ethylen.e glycol ulonomethyl Qther acetate, diethylene glycol monomcthyl ethar, diethylene glycol monoethyl ether, atbyleut glycol mono-a-propyl 1$
ether, ethylene glycol mono-isopropyl etber, dietli.ylexte glycol mono-isopropyl etlier, ethyleu.e glycol uiouo-n-buryl etber, diethylene glycol mono-n-butyl ottur, triethylane glycol m.ono-u-butyl ether, ethylena glycol moflo-t butyl ether, diethyleue glycol monu-t butyl ether, 1-met,hyl-l-methoxybutanol, propylene glycol monomethyl ether, propylene glycol mouoethyl ether, propylane glycol umno-t-butyl ether, propylene glycol mono-n-prapyl ether, propylepe glycol mono-isopropyl erher, diprepylene glycol monornathyl ether, dipropylene giycol manoethyl ether, dipropylene glycol mouo-n-propyl eftr, dipropylene glycoi mono-isopropyl ether, prof,ylene glycol mono-ti-butyl ether, and dipropylene glycol mono-n-butyl ether. Examples of suitable ],2-alkyldiols are 1.,2-pen't$ea.edioX and 1,2-hexanedio]. The peneizan.t may also be selected from straight-chain hydrocarbon didls, such as 1,3-propanediol, 1,4-butanediol, 1,5-pentatedial, 1,6-haxauediol, 1,7-beptsiuediol, and 1,8-octaaediol. Glycnrol nr urea :t.nay 81so be used as penetrants.
The amount ofpeneh'aut is preferably in the range of 1 to 20% by %cight, tuore preferably 1 to 10%
by weigh#, based on the total ink contposition.
The inkjet iulc may also contain a surface active agattt, especial.iy an anionic surface active agent and/or a nonionic surface aotive agent. Useful anionic surface active ageuts inelude sulfonie acid types, suoh as alkanesulfouic acid salts, ot-ole$nsulfdn.ic acid salts, altcylbensenesulfouic ixaid sÃr4ts, allcylnapbthaleues'uVonie aeids, acylutethyltautittes, and diallcylsulfosucGinic acids; all;ylsu,l.furie ester salts, sulfated oils, sulfatetl olef4ts, polyoxyetlrylene alkyl ether sulfitrio ester salts; carboxylic acid types, e.g., fatky acid salts and alkylssrcosine salts; aud phosphoric acid ester types, such as all4.ylphosphoric ester salts, polyoxyetbylene alkyl cttxtr pltospboric ester salts, and glycempbospharic ester salts. Specific exara.ples of the &uionic surface active agents are sodium dodecylbenzenesulfonate, sodi.txm laurate, and a polyoxycthyleA.e a.lk.yl et,ber sulfate amtuptxittut salt.
SuitaUle nonionic surfece active agerits include ethyland exide adduct types, such as polyox.ycthyl= aUryl ethers, polyoxyethyleno 441plleuyl ethers, polyoxyethylone alkyl estet's, and polyoxyethylene alkylamides; polyol ester tyges, such as glyorol alkyl esters, sorbitan alkyl esters, and sugar alkyl asters; polyether types, suoh as polyhydric alcohol alky] ethers; and alkan4latnidE types, such as aUcanolatnuxe fatity aeid.atnides. Spccifc examples of nonionic surface activa agents ara etllzrs such as polyoxyethylene nonylphenyl ether, polyoxyathylene octyYphenyl ether, poiyoxyethyleno dodacylpheuyl ettxer, polyoxyethylene alkylallyl ether, polyoxyethylene oleyl ether, polyoxysthylette lauryl ether, and poiyoxyalkylene alkyl ethers (e.g. polyoxy+athylepe aJk.yl ethers), annd esters, such as poly4xyothylene olesate, polyoxyethylene oleate estar, polyoxyethylene distearate, siarbitan lauraw, sorbim mouostearate, sorbitan mono-oleate, sorbitan sesquioleate, polyoxyethylene rnono-oleate, and polyoxycthylene stearate. Acetylene glycol surface aetive agents, such as 2,4,7,9-tetramethyl-5-decyne-4,7-4iol, 3,6-dimethyl4-oetyne-3,6-diol or 3,5-diinethyl-l-hexyn-3-ol, tnay also be used.
The iniejet ink may also include a biocide, such as benzoic acid, dichloropbene, hexachlorophene, sorbic acid, hydroxybenzoic esters, sodium dehydroacetate, 1,2-bcnthiazolin-3-one, 3,4-isotbiazoliu-3-one or 4,4-dimethyloxazolidine.
The ink7et ink may also contain a sequestering agent, such as ethylenediaminetetraacetic acid (MTA)_ The ink;jet ixtk t>a8y also contain a singlet oxygen qeenoher. The presence of singlet oxygen quencher(s) in the irlJc reduces the prupmsity for the IR-$hsorbing dye to degrade. The quencher constttnes aity singlet oxygen genoratccl in the vicitiity of the dye molecules aud, bience, minimizes their degradation.

An exce3s of singlet oxygen quencher is advantagauus for winimizing degradation of the dye and rGtaining its M-absorbing properties over timc. Prefer$bly, the singlet oxygen quenc#uor is selected from ascorbic acid, 1,44azabieyclo-[2.2.2]octane (73A13CQ), azides (e.g, sodium azide), ttistidine or tsyptopha.u.

I e7 Printer-s The present invention also provides au inlcj et priater comprising a pritlthead in #luid communication with at Ieast one ink reservoir, wherein said ink reservoir Compt7ses an iAkjet ink as descn~bed above.
Inlcjet priuters, such as thermal bubble jet aud piezoelectric printers, axe well known in the art aud will form part of the sk3.lled person's common geueral kttowledge. The printer axuy be a high-speed inkjet printar. The printer is prcfarably a pagewidth printer. Praferred iralcjet printers and pr'-.ntheads fot use in the present inventiott are descrtbed in the follawiAg pateut applications, all of which are incorporated herein by rt~fet'ence ia their entirety.
10/302,274 6692108 6672709 10/303,348 6672710 6669334 10/302,668 10/302,577 6669333 10/302,618 10/302,617 10/302,297 .Prindhepd A MctAjet pri.qter generally has two pritttbead integrtttrxl circuits tl7at are mounted adjacent each other to form a pagcwidth pri-uthead. Typically, the printhead ICs can vary in sixe from 2 h.tches to 8 inches, so several cotnbimtions can be usod to produce, say, an A4 pugc'cvidth prittthead. For examplo two priathead ICs of 7 and 3 inches, 2 ud 4 inches, or 5 and S inches could be used to ereate an A4 ptinibead (the nQtatiou is 7:3). Similarly 6 and 4 (6:4) or 5 and 5 (5:5) combiuatiops can be used, An A3 printh.ead can be constructed from 8 and 6-inch printhead integmted circuits, for axaulplg. For photographic prin.tiA.g, particularly in caiuera, smaller priutheads can be uaed, It will also be appreciated that a single printhead integrated circiut, or more than two such circuits, can also be used to achieve the raquirGd printhead width.
A preferred printhea.d embodiment of the pinthead will now be described with reference to Figtums.
17 apd 18. A printbead 420 takes the ffirm of an elongate unit. As best shown in Figure 18, the componen.t9 of the printhead 420 include a support member 421, a flexible PCB 422, an ink distribution molding 423, an ink distributiota plate 424, a MEMS printhead comprising first and second ptinthead integrated circuits (ICs) 425 and 426, and busbars 427.
The support niember 421 is can be formed from any suitable matetial, such as metal or plastic, and can be extraded, rnoided or formed in any other way. The s'upport member 421 should be sttong enough to hold the other components in the appropriate aligiuuent relative to each other whilst stiffening and strengthening the printhead as a whole.
The #lexi-ble pCB extends the length of the printhead 420 and includes first and second electrical connectors 428 and 429. The eleattical connectors 428 $nd 429 correspond with flexible connectors (not shown). The electrical connectors include oontaet areas 450 and 460 that, in use, aie positiotxed in eontaot rovith corresponding output connectors from a SoPEC chip (not shown), Data from the SoPEC chip passes alang the electrical eonneetors 428 aqd 429, and is distributed to respective ends of the first and second ptxnthead ICs 425 and 426.
As shown in Figute 19, the ink d.islxibution molding 423 includes a plurality of eloagate conduits 430 that disttibute fluids (ie, colored inks, infrared ink and fxxative) aud pressurized air from the air pump alou.g the length of the printhead 420 (Figure 18). Sets of fluid apertures 431 (Eigure 20) disposed along the length of the iuk distribution tnoldiAg 423 distribute tho fluids arad air from the conduits 430 to the ink distribution plate 424. The fluids and air are supplied via nozzles 440 foruted on a plug 441 (Figure 21), which plugs into a corresponding socket (not shown) in the pririter.
5 The distributiarx plate 424 is a multi-layer censtcuction configGUvd to take tluids prbvided locally &om tbe fluid apertures 431 and distribute them through smallcr distributiou apertures 432 into the printhead ICs 425 and 426 (as shown in Figure 20).
The printhead ICs 425 and 426 are positioned end to extd, and are held in contact with the distribution plate 424 so that ink from the sXpaller distrnbution apertures 432 can be fed into correspoudiug 10 apertures (not shown) in the priuthead ICs 425 and 426.
The busbarb 427 are relatively high-capacity copductors positioned to provide drive current to tlte actuators of the priuthead nozzles (clescribed in detail below). As best shown in Figure 20, tYte busbars 427 are retained in position at one end by a socket 433, aud at both ends by wrap-aro"d wings 434 of the f1.ex.ible PC13 422. The busbars also hclp hold the printltead IGa 425 in position.
15 As shown best itn p'igure 18, when assembled, the flexible PC3 422 is effectively wrapped aTound tho other components, thereby hold`ung tliom in contact with wh other, Notwithsiandiug this binding effect, tbe support member 421 provides a major proportion of the required stiFness and strength of the printhead 420 as a whole.
Two forms ofprirtthead uoz.zles ("tt-ermal bend actuatori0 and "bubble forming heater eleraept 20 actuator"), suitables far use in the printheatl dtscribed above, will now be described.

Therrnu! i4end Ac#uator In the ihermal bend acu.tator, there is typically provided a nozzle arrangement having a nozzle chanber containing ink aud a thetYnal bend actuator conneoted to a paddle positioned within tba charaber.
The thermal actuator device is actaated so as ta eject ink fronm the nQz,zle oltamber. The preferred embodiment includes a particular thermal bend actuator which includes a series of tapered p4rtious for providing conductive heating of a conductive trace. The actuator is c,onnacted to the paddle via an arru reeeived through a slotted wall of tho nozzle chamber. The actuator arm has a mAtin.g shape so as to mate substantially with tha surfaces of the slot in the uozzlo chamber wall.
Turning initially to p'igures 22(a)-(c), there is provided schematic illustrations o#'tle basic operation of a nozzle arrangement of this embodimant. A nozzle chamber 501 is provided filled with ink 502 by means of an ink inlet channe1503 which can be otohed through a wafer substrate on which the nozzle chamber 501 rests. The nozzle chamber 501 further includu an ink ejection port 504 around which an ink meniscus forrns.
Inside the nozzle chamber 501 is a paddld type device 507 which is interconnected rn an actuator 508 through a slot in the wall of the nozzle ohan'sber 501. `I'be actuator 508 includes a heater meanh c.g. 509 located adjacept to an end portion of a post 510. The post 510 is ftxed to a substrate.
When it is desi:'red to eject a drop from the nozzle chamber 501, as illustrated iix Figure 22(b), the Iteater means 509 is heaterc3 so as to tmdergo thermal expansion. Preferably, the heater means 509 itself or the other portions of the actuatoi' 508 axe built from materia.ls having a high betqd efficiency where the bend efI"iciency is defned as;

bend e,f,jiciency = Young's Afoduius x (Coeffcaent of thermal Expansion) Density x Speo:'ftc Heat Capacity A suitable tnaMt'ial for the heater elemaats is a copper nicke1 alloy wWoh can be formed so as to bend a glass material.
Tha hnater means 509 is ideally located adjacent the end portion of the post 510 such that the effects of activation ara magni-fied at the paddle gud 507 such that small thernial expansions near the post 510 result in large movements of the paddle end.
The heater means 509 and pprtaeqliential paddle moverneut causes a general increase in pressure around the ink meniscus 505 which expau.ds, as illu3trated in Figure 22(b), in a rapid Wauner. The lteater current is pulsed and ink is ejeet.ed out of the port 504 in addition to flowing in from the ink channel 503.
Subsequentiy, the paddle 507 is deactivated to again repm to its quiescent position. The deactivation causes a gerteral xeflotiv of the ink into the ncrzlc chamber.
The fnt'ward motrYeotupq of the ink outside the nozzle rim and the corresponding b=ackflow results in a ganeral uac}ciug and brealdag off of the drop 512 which proceeds to the printmedia. The oollap5ed tneniscus 505 results in a general sucking of ink iuto the nozzle cham-bcr 502 via the iuk flow ehaanel 503. In time, the nozzle ehamber 501 is refilled such that the position in Figure 22(a) is agaiu reached and the nozxlo chaxqber is subsequently ready for the ejection of another drop of ink.
Figure 23 illustratas a side pers,pective view of the ixozzle arrangement.
Figure 24 illustrates sectional view thTough an array of nozzle & mugement of Bigure 23. In these fignres, the numbering of elements previously ultroduced has been rctaiued.
Firstly, the actuator 508 includes a series oftaperdd actuator units e.g. 515 which comprise an upper glass portion (amorphous silicon dioxide) 516 fQmed on top of a titanium nittide layer 517. ?.itematively a copper nickel alloy layer (hereinaRor called eupronickel) can be utilized which will have a higher bezid cfftciency.
The titanium nitride layer 5171s in a tapered form and, as such, resistive heating talccs place t-eax an end portion of the post 510. Adjacent titanium uitride/giss porlious 515 are hlterconnected at a block portion 519 which also provides a mechanical struotural suppon for the actuatar 508, The lieater means 509 ideally iucludes a plurality of the tapeted aeEuator unit 5 15 which ara clongate and spaced apart such that, upon heating, tle. bending force exhibited along the axis of the actuator 508 is snaximized. Slots are dafined between adjacent tapered units 51$ and allow for slight differential oparatiott of each actuator 508 with respect to adjacent actuators 508.
Tha block portion 519 is intcroonnc~cted to au arm 520. The arru 520 is in turn couqected to the paddle 507 inside the nozzle chamber 501 by means of a slot e.g. 522 formed in the side of the nozzle chamber 501. The slot 522 is desigped generally to mate with Ghe surfar.es of tb.e arm 520 so as to minimize appor-btn.ities for the outflow of ink around the a.t'rr.t 520. Tlte ink is held generally within the nozzle chamber 501 via surface tensiott effects around Xhe slot 522.
When it is desired to actuate the arm 520, a conduccive current is passed through the titauiuru nitxide layv-r 517 via vias within the block portion 519 connecting to a lower CMOS
layer 506 which provides t.he necessary power and contt'ol circuitry for tlie nozzle arrdngement The couductive current results in heating of the nitride layer 517 adjacent to the post 5 10 which results in a general upward bending of the arm 20 aud consequeutial ejection of ink out of the nozzle 504. The ejected drop is printed on a page in the usual m$nnsr for an inlcj et priutor as previously described.
An array of nozzle amngements oan be formed so as to creata a single parinthead. For exatnple, in Pigure 24 there is illusirated a paCGly sectioned variaus arru.y vierw which comprises multiple ink ejectioq nozzle arra.ngements of Figure 231aici out in inteTleaved 1'tms so as to form a priuthead anay. Of course, difl'armit types of arrays cuia be formulated including full color atrays etc.
The constructi.4n of the prb.tthead system dasoribed can proceed utilizing stanclaA .MEMS
tedhniques tbrough suitable modificatiau of the steps as set nut in US
6,243,113. entitled "Image Creation Method and Apparatus (IJ 41)" to the present applicant, the contents of which are fully incorporated by cross referenee.

Rubble F'orming Heater.Elemertt Aatua#ar With reference to Figura 17, the unit cell 1001 of a bubble forming heaterelement actuator comprises a nozzlc plate 1002 with nazzie31003 therein, the t#ozzles having nozzle rims 1004; and aperGUres 1005 extc-nditig T.hrough'tb.e nozzle piate. The uozzle plate 1002 is plasma etched from a silieart nitride structure which is depositeci, by way of chemical vapor deposition (CVID), over a sacrificial mate'ial which is subsecluantly etcbed.
The printhead also includes, with respect to csachnozzle 1003, side walls 1006 on which the nozzle plate is suppocted, a chatnber 1007 de$ned by the walls aad the nozzle plate 1002, a multi-layer sabstrate 1008 and an inlet passage 1009 extandiug tbrough the mplti-layer substrate to the far side (not shown) of the substrate. A looped, elongate heater elerAetU 1010 is su3peuded within the chaauber 1007, so that the element is in the form of a suspended beam. The printh&ad as shown is a uucroelectromechaaical system (MEMS) structure, which is formed by a lithographic procm.
When the printhead is in use, ink 1011 from a reser<+'oir (not shown) enters the chamber 1007 via the inlet passttge 1009, sa that the chamber fills. Thereafter, the heater element 1010 is heated for samewhat less than I micro second, so that the heating is in the form of a thermal pulse. It wilt be appreciated that the heater element 1010 is iu thermal contact with the ink 1011 in the chamber 1007 so that when the elexpent is heatcd, this causes the geeneratiau of vapof bubbles in the ink. Accordingly, the iulc 1011 constitutes a btsbble form_in.g liquid.
The bubble 1012, once generated, causes an increase in pressure wit.hiu tlte ctAmber 1007, wWch in turn causes the ejesotiou of a drop 1016 of the ink.1011 tbrough the nozzle 1003. Tb.e ri.m 1004 assists in directing #he drop 1016 as it is ejeeled, so as to minunizd the cbance of a drop misdiractiou.
The reason that theres is ouly one nozzle 1003 ancl ch$mber 1007 per inlet passage 1009 is so that the pressure wave generated within the chamber, on heating of tha alemcnt 1010 and forming of a bubbla 1012, does not effeot ac(jaoeat chambers and their corresponding nozzles.
The incretcse in pressure within the chamber 1007 not only pushes ink 1011 out through the nozzle 1003, but also pushes same ink back tbrougl- the inlet passage 1009. However, the inlet passage 1009 is approximately 200 to 300 microns in length, and is only approximately 16 microns in diameter. Hence there is a substantial viscoua drag. As a result, the predominatit effect of the pressure rise in the chamber 1007 is to force iqk out through tho uozxle 1003 as an ejeoted drop 1016, rather than back through the inlet passage 9.

As shown in Figure 17, the ink drop 1016 is being ejected is shown during irs "necki.ng phase"
before the drop breaks off. At this stage, the bubble 1012 h&s already roached its maximum size and bas thea beguat to collapse towards the point of collapse 1017.
The collagsing of the bubble 1012 towards t11e point of collapse 1017 causes some ink 1011 to be drawn from within the ndzzle 1003 (frorn tlj~ sides 1018 of the drop), and some to be drawn from the inlet passage 1009, towards the point of co[lapse. Most of the ink 1011 drawn in this manner is drawn from the nozzle 1003, forAlin,g; an aunular tieclc 1019 at the base of the drop 16 ptio,c to its breaking off.
The drop 1016 requires a certain ainoutlt of momentum to overcome surface tertsion foroas, in order to break off. As ink 1011 is drawn from the r.lozzle 1003 by the collapse of the bubble 1012, the diameter of the neck 1019 reduces thereby reducing the amount of total suCface tepsioq holding the drop, so that the motnentuni of the drop as it is ejected out of the nozzle is suffic'sent to allow tha drpp to fareak off.
When the drop 1016 breaks off, cavitation forces are caused as reflected by the arrows 1020, as the bubble 1012 collapses to the point of collapse 1017. It'wi11 be noted that there are no solid surfaces in the vicinity of thts point of collapse 1017 on which the c&vitatian can havd an Offect.
inlcjet CartritlQ=es The present invendon also provides an iulcjdt ink carttidge comprisitrg au irrk,jet ink as descn'bed above. Ink carhidges for ink,jet ptiuters are well known in the art and are availrt~ble in numerous fortus.
Preferahly, tlle irtkjet ink cartridges of tha presaut invention are replaceable. Inkjet cartridges suitable for use in the present inveution are described in the following patent applications, all of wttioh are iucorporated herein by refereace in their entirety.
642815S, 10/171,987 In one preferred farm, tho ink cartridge Gomprises:
$ housing defining a plurality of storage areas w}zertin at least one of th4 storAge areas contains colorant for printing utfamation that is visiblo to the huruM eye aud $t least one of the othef storage areas contains an inkjet ink as descn~aed above.
Proforably, each storage area is s#zed corr$spouding to the expeetei levels of use of its copteats relative to the intendecl print covorago for a number vfprinted pages.
There now follows a brief description of an ink cartridge according to the preseut invention. Figuro 12 shows the complete assembly of the replaeeable ink carhidge 627. It has bladdeers or chambers for storing fixative 644, adhesive 630, and cyan 631, magenta 632, yellow 633, black 634 and infrared 635 inks. The carnidge 627 also contains a niicro air fiiter 636 in a base molding 637. As shown in Figure 9, the micro $ir filter 636 irtterfaces with an air pump 638 inside the ptintar via a hoso 639.
This provides fatered air to the printheads 705 to prevent ingress of micro particles into the MemjetTM
printheads 705 which may clog t3ae nozzles. By incorporating the air filter 636 within the cartridge 627, the operational life of the filter is effectively linked t4 the life afthe cartri.dge. This ensures that the filter is replaced together with the cartridge rather than relying on tbe user to clean or replace ft- ftlter at the recluirecl iritervals. Furtherutore, the adhesive and infrared ink are replenished together with the visible inks and air filter thereby reducing bnw freclueutty the printer operation is izuerrttpted beeause of the depletion of a consumable material.
The carGt'idge 627 has a tb'1n waU casitlg 640. The ink bladders 631 to 635 and fixitive bladder 644 are suspended within tha casing by a pin 645 wliich hooks the carq idge together.
The sitigle glue biacider 630 is accomtnoclated in the base molding 637. This is a fully recyclable product with a capacity for printing and gluing 3000 pages (1500 sbeets).

es Substra As cnent.ioned above, the dyes of the present iuveution are especWly sait$b(e for use ia Hypertabeff and nepage systems. Such systems are descri`bed in more detail below and in the patent applications listed above, a11 of which are incorpmted hetein by refereace in their entixety, Hence, the present invention provides a substrate having an 1R-absorbing dye as described above disposed thereon. Preferably, the seabstrate comprises an interface surface.
Preferably, the dye is disposed in the fnrm of coded data suitable for use in netpage auci/or HyperlabeP systems.
For example, the coded data may be indicutive of the identity of $ product item. Preferably, the coded data is dispoaod over a substanti#I
portion of an interface surf4oe of t1ie substrate (e.g. greater than 20%, greater tbau 50/'0 or greater tbau 90%
of the surface).
Preferably, tlle substrate is IR reflective so that tltas dye clisposed thereon may be detected by a sensisYg device. The substrate may be comprised of any suitable material such as plastics (e.g. polyotefins, polyesters, polyam.ides etc.), paper, metal or combinations ther$of.
For netpage applicatious, the substrate is preferably a paper short.
ForHyperlabeP $pplications, the subsbmte is prefet4bly a ta$, a label, at packagiug uutterial or a surface of a product item. 'Fypically, tags and labels are oamprised ofpl$stics, paper or combinatious t1amf.
.Tp accordance with HyperlabeP applications of the invention, the substtate tuay be an interactive product item acjapted for ip.ter$etion with a user via a sensing device and a computer system, tho iavtatactive prodl3et item comprising:
a product it.czkt having an ideittity;
an intcrface sttrfaoe associated with the product itam anci having disposed thereon iuforrnation relating to the product iteut and coded data indicative of the identity of the prod'i:tot item, wherein said codod data comprise su M-absorbip.g dye as described above, N'etpage attd pe.rlahel~
Netpage applic&tions of this invention are dcscribed gencrall.y in the sixth and seventh aspects of the invention above. HyperlabtlP applications of this in.ventiott are described generally in tbo eighth and uirit>s aspects 4ftkle invention 4bove.
There now follows a detailed overview of netpage and Hyper3abeff. (Note:
MerAjet'r"i and HyperlabeP are trade marks of Silve.rbrook Roscarch Pty Ltd. Austratia). Tt will be appreciated that pot every impimeuta,tion wi]1 uecessarily mboc)y all or even most of the specific details and extensiors discussed bel4w in relaaon to the basic system. However, the system is described in its most complete form to reduce the need for external reference w]tou attatuptiug to lmderstaud the comext in which the preferred embodiments and aspects of the present invention operate, ln brief sutnm4ry, the prel'erred form of the netpage systetn employs $
computer interface in tha form of a mapped sut face, that is, a physical surfaee which contains references to a map of tbe surface maintained in a cotnpttter systetn The =p reterences m be queried by an appropriate sensing device.
Depending upon the specific implementation, the map references may be encoded visibly or itYvisibly, and defted in suc)i a way that a loca.l quefy otY the mapped surfece yjelds an uqatnbiguous trtap referepce both within the map and among diffftvnt tnaps. The eomputer system can contain iufonmtion about fe$t-xres on the mapped surface, and such iaformation can be retrieved based on map references supplied by a seusing device used with the ntapped surface. T'he ittfornatioxt thus retrieved cati take the form of actions which are 5 initiated by the coinputer systenl on behalf of the operator in response to the operator's iuteractiorl with the sutface featnres.
In its preferred form, the nctpage system rel.ies on the production of, $u4 human interaction with, netpages. These a,re pages of text, graphics and images printed on ordinary p"G, but which work like interactive web pages. Xpformmstton is euco4ed on each page using ink wlsich is substautially invisible to the 10 unaided human eye. The inlc, llawever, and thCreby tha coded d$ta, can be sensed by an optically imaging pen and transmittad to the netpage systetxt.
In the preferred form, active buttons and h.yptrliu3rs ou each page aan be clicked with the pen ta requcat inforal.ation from the rtetworle or to signal preferencGa to a ne=tworts server. Xn one embodiment, text written by hand on a netpage is automatieally recognized and cauverted to computer text in the netpage 15 system, allowing fnmts to be filled in. In other etnbodiments, signatures rscorded on a netpage are autouuatically vexified, allowing e-commerce transactious to be securely authorized.
As illustrated itt. pigure 1, a printed nej*page 1Qan represew an interactive form which can be #-i]]ed in by the user both physically, on tite printed page, and "electronically", via commuqication between the pen &nd the petpage system. The example shows a"1tequesC' form eotxtaining name and addrtss fields 20 and a submit button. The netpa.ge consists of gi'aphic data 2 printetl using visible inJc, and coded data 3 printed as a collectiuan of tags 4 u3iug ianvisible iuk. The corresponding page dosoription. 5, stored on the netpagc netw4rk, describes the iudi.vid.ual elernents of the natpage. Tn paztioulat it describes the type and spatial extent (zone) of each interactive element (i.e. text field or buttoa in the example), to allow tbe netpa.ge systexn to correatly iuterpret input via the uetpage. The submit buttvn 6, for example, has a xom 7which 25 corresponds to the spatial extent of the correspondiug grapliic 8.
As illustrated in Figure 2, ttte netpage pen 101, a prefxsrred f4rtu of whiah is shown in Figures 6 and 7 and described in tnore detail below, works in conjunction with a personal computer (PC), Web terminal 75, or a netpage printer 601. The netpage printer is an 7xiwrnet-connected printing appliance for home, office or mobile use. The pen is wireless and communicates securely with the netpage network via a short-rsnga radio linlc 9. Short-range commuxucatiotl is relayed to the netpage network by a local relay functlan which is cithcr cmbc&1GCI in the PC, Web terminal or notpage ,printer, or is provided by a separate relay device 44.1 he relay function can also be provided by a mobile phone or other device which incoiporates both short-range and longer-rauge cotnmrxn.icatlons funotions.
In an altemative em]aadimen.t, the netpage pen utilises a wired connection, such as a USB or other serial conhection, to the PC, Web terminal, netpage printer or relay device.
The netpage pri.nter 601, a preferred form of which is shown in 1~igures 9 to 11 and described in more detail belovcr, is able to deliver, periodically or on demand, pcrsonatized newspapees, tnagazines, cata.logs, brochures and other public$tiorts, allj printed at high quality as interactive netpages. Unlike a pmonal computer, the netpage printer is w appliance which can be, for example, wall-mounted adjacent to an area where the inorning news is first consumed, srach as in a user's kitchan, near a breakfast table, or near the household's point of departure for the day. It also comes in tabletop, desktop, portable and miniacute versions.
Netpages printed at tlheir point of o4nsun7ption combine the ease-of-use of paper with the timeliness aad interactivity of an interactive medium.
As shown ir1 p'igure 2, the netpage pea 101 interacts with the coded data on a printed netpage 1(or product item 201) and conurtuqicates the iateractiort via a short-range radio 1irk 9 to a relay. The relay sonds tbe interaction to the relevant netpage page server 10 for interpretadoti In appropriatc bircumstances, the page setver sends a corresponding message to application computer software running on a uetpage application server 13. The applicatiou server may in turn send a response which is printed on the originating printer.
In an alte~=tive etnbodim,out, the PC, Web terminal, netpage printer or relay device may communicate direotly with local or remote application softvvare, including a local or remote Web server, Relatedly, output is wt limited to being prulted by the netpage printer. It can also be displ$yed on the PC or Web teimiua.l, and further interaction can be screen-based rather than paper-b", or a mixtura of ft two.
The aatpage system is made oonsiderably mara convenient in the preferred embodiment by being used xn conjunction witll higli-speed mioroeleotcomechanical system (ivlEMS) based inkjet (Meu}jetTm) printers. Tu tbe preferred fortu of tlus technology, relatively high-speecl Wd high-quality priut3ug is made more affordable to consumers. In its preferred form, a netpage pttblicaCion has the physical clmcteristics of a traditibnal newsmagazine, such as a set of letter-size glossy pages printed in full color on both sides, bound togetl2er for easy navigation and comfortable handling.
The netpage printer exploits the growing availability of broadband In.ternet access. Cable serv,ice is available to 95% of households in the United States, s11d cable modem sarvice offerisYg broadband T.nternet access is already available to 20% of theso. The netpage printer can also operate with slower connections, but witb longer delivery tir.ues and lower imase quality. Indeed, the netpage system caa be ettabled using existing cous<amer ipkjet and laser printers, althnugh the system wi11 operate tnore slowly and will thcrefore be less acceptable from a eonsumer's point of vievv. In other embodiments, the netpage system is hosted on a private iutxauet. Xti still otber am.bodimerxts, the netpage system is hosted on a single computer or coinputcr-enabled device, such as a printer.
N'etpage publication servers 14 an the netpage network are co4gured to deliver print-guality publications to netpage printers. Periodical publications are delivered autotnatically to subscribing netpage printers via pQiutcasting and multicayting Ioternet protocols. Personalized publicstions are filtered and formatted according to iridividud user profles.
A netpase printer can be configured to support $uy number of pens; and a pen can work with any number.of netpage printers. In the preferred implementation, each uetpagt~ pen bas eaniqpe identitex. A
household may have a collection of colored aetpage pens, one assigued to eackt member of the fauiily. This, allows each user to maintain a distinct profile with respect to a net,pagt publicatioa server or application server.
A uctpage-pea can also be registered Witb a uetpage registration server 11 and linked to one or more payment card accounts. This allows e-comrnerae paymonts to be securely authorized using the netpsge pen. The netpage tegigtratiozi server compares ther siguature captured by the netpage perx 'with a previously registered signature, allowing it to authenticate the user's identity to an e-commerce server. odysr biorluitrics can also be used to Verify identity. A version of the netpage pen includes fingerprint scanning, verified in a similar way by the netpage registration server.
Althougk a petpage pritt.tsr may deliver periodicals such as the morning newspaper without user intervention, it can be configured never to daliv6r unsoticited junk ulma.il.
In its prefeired form, it only &li'vers periadicaXs frorn subscribed ar okherwi.9e authot'ized sources. Yn this respeet, t.he netpage printer is unlike a fax machine or e-mail account which is visible to any junk maiter who knows t#1e telaphone nurnber or email address.

Each objxt model in the systepl is desaribed using a Unified Modeling Language (UML) class diagra<u A ela.ss diagraux cousists of a set of object classes connected by relatiouships, aud two kiuds of relationships are of interest here: associations and generalizations. An association re,presemts some kind of relationship between objects, i.e. between insfa.nces of classea. A
gene,ralization relates actual classes, and oau be u nderstood in the following way: if & class is thottght of as the set of 811 objects of that class, and ola.ss A is a generalization of class E, then f3 is simply a subset of A. 'I'he [JMI.
doas not directly support sdeond-order modelling - i.e. classes of classes.
Each olass is dr$wn as a rectangle ]aballed with the name' of the class. It contains a list of thC
attmlbutes of the class, separ&ted ffo:pa the pa.me by a horizontal line, and a list of the operations of the class, separated from the attributa list by a horizontal line. In the class diagrams wh.ictl follow, however, operations aro never uwdelled.
An association is drawn as a line joining two classes, optionally lubelled at either end with the muldplicity of the association. The defxult multiplicity is one. An asterisk (*) indicates a multiplicity of "many", U. zero or rnore. l'ach asaoeiation is optionally labelled with its name, and is also optionally laballad at eitb.er cnd with 13le role of the corresponding class. .A-u open diamond indicates an aggregation association ("is-part-of`), and is drawn at the aggregator end of the association line.
A generaiization relatioAship is drawn as a solid line joining two classes, with an armw (in thc forua of an open triangle) at the generalization end.
When a class diagram is brokm up into multiple diagrams, any class whieh is duplieated is showa with a dashed ourline in all but the main diagram wb.ich defiues it. It is shown with attribqtes only wltere it is defiued.
1.1 NETPAGES
NeApages are the foundgtion on which a netpage network is baiit. They provide a paperLLbased user interface to published informtxou aud interactive services.
A. netpage consists of a printed page (or other sttrface region) invisibly tagged with rEfercgces fA
an anline description of the page. The online page description is maintained persistently by a neqaage page server.l'he page description descrt'bes the visible layout and content of the page, including text, graphies and images. It a4so describes tlie input eler.pem on the page, incFuding bu.ttous, hyperlinks, and input felds. A
net,page allows markings mada witb a netpage pen on its surface to be simuJtaneously captared and processed by the netpage system.
Multiple netpages can share the same page description. FIowever, to allow input tlrrough otherwise idcntical pages to be distYnguished, each netpage is assiped a unique page ident9fier. This page ID
has sufficient precision to di.stinguish between a very large number of n6tpages.

Each refeteaee to the pa$e description is encoded in a printed tag. The tag idecitifies the unique page an vvhich it appears, and tttereisy indirectly identifies the page deseription. The tag atso identifies irs owu position on the page. ChatacteXistics of the tags ara described in more detail below.
Tags are printed iu infrared-&bsorptive ink on any substrate which is infrared-ref7eeti've, suc$ as ordinary paper. Near-itlfrared wavelength.s are iuvislble to the luunan eye but are easily sensed by asolid-state image sensor with $u appropriate filter.
A tag is set.tis0d by an are$ iMage sensor in the netpage pea, and the tag data is trarr.miitted to the netpage system via the nearest nctpage prltlter. The pen is wireless aud comtnunicates with the netpage printer via a short-rauge radio lit7k. Tags are suflciext.tly stnall and densely a.i'tanged that the pen Gan reliably iniage at Idast one tag even on a single click on the page. It is irnportant that the pen recognize the page ID
and position on avery i>steraction with the page, since the intdraction is stateless. Tags are ercor-cotrectably encoded to uui.ke tbem partially toEerapt to surface damage.
Tbe netpage page server ruAa.n.t8ins a unique page instance for eacb.printcd netpage, allowing it to maiutalu a distinct set of user-supplied values for input fiblds in the page description for eaeh printed netpage.
The relationship between tlu pap description, the page instttace, and the printed taetpage is shown in pigure 4. Tlia printec3 netpage may ba part of a printed netpage docuuxeAt 45. The page iustane,e is associated with both the netpaga priutar wJtich printed it and, if knowp, the uetpage user wha requested it.
As shown in fig'ure 4, one or more uetpsges may also be associated with a physical objeCt such as a product item, for example vvhep pxinted onto the pruduct itetn's label, packaging, or aotttal surface.
1.2 NETPAGE TAGS
1.2.1 Tag Uata Content in a preferred form, each tag idetlliftes the region in urb-ich it appears, and the location of that tag witlvn the region. A tag may also contain flags which relate to the region as a whole or to the tag. One or more flag bits may, for axample, signal a tag seasiug device to provide feedback indicative of a funntioti associated with the iraxuediatt area of the tag, without the smsiug device having to refer to a description of the regiou. A netpage pert may, for exarnple, illumir= an "active area" L,pD
wlteu izt the zone of a hyperlitnk.
As will be more alearly explained below, in a preferred embodirnent, eaclt tag contaim an easily recognized invariaatt structure wlaioh aids initial detection, and wfuch assists in mutittxizing the effect of any warp induced by the surfaeC or by the sensing process. The tags preferably tile 'the entire page, and are sufficiently staaall and densely arranged that the pen can reliably image at least aue tag even on a single click an tbe page. It is important that the pen recogni2e the page ID and position on every interaction with the page, since the interaotidn is st&telm.
In a preferred embodiinenk the region to wktich a tag rofcrs coincides with an entira paga, and the regidn ID emoded in the tag is tbexefore synonymous with the page ID of the page on which the tag appears.
in other embodiments, the ragitsn to wlxioh a tag refers can be an arbitrary subregion of a page or other surface. For exanlple, it cau coincide with the zoue of an i0ter4etive element, in whieh case the region ID caa direotly iderGtiify the interactive element In the prefeved foxm, each tag contains 120 bits of ittfortnation. The regiott lD is typically allocated up to 100 bits, the tag ID at least 16 bits, and the remaining bits ate allooated to flags etc. Assuming a tag density of 64 per square inch, a 16-bit tag M supports a region size of up to 1024 square inches. Larger regions can be mapped continuously without increasing the tag 173 precision sitnply by using abutting regions od maps. The 100-bit region .1Jp allows 21Q0 (-10"' or a million trillion tri3lion) tiifferent regions to be uniquely identified 41212 Tag Data Encoding lu one embodiment, the 120 bits of tag data are redundantty an.cocled using a (15, 5) Reed-5oloittott code. This yields 360 encoded bits cousisting of 6 eodewords of 15 4-bit symbols each. Thd (15, 5) aode allows up to S symbol errors to be corrected per codeword, i,e. it is tolerant of a symbol error rate of up to 33% per codeword. , F-ach 4-bit symboi is represented in a spatially coherent way in the tag, and th$ symbols of the six codawords are interleaved spatially witktin the mg. This ensures that a burst erxor (an error affecting inultipln spatially adjacer.tt bits) damages a minizuu.m number of symbols overall and a uaini.meU'A number of symbols in any one cocleword, thus maxim;sing ft likelihood that the burst error can be fally corrtisctect.
Any suitable error-c4rrtotirlg code code can be usbd in place of a(1 S, 5) Reed-Solomon code, for ~ S examplG: a Reed-Solomon code with more or less redundancy, with tbe satne or different symbol and codeword sizes; another block code; or a diff'arent kixd of eode, such as a oouvoluaonal code (see, for ex=ple, StepJlen B. Wicker, 1/rxor Control Systems for Y3igital Communication s.ad Stoxage, Prentice-Hall 1995, the 4outents of which a herein incorporated by reference thereto).
In order to support ,single-click" intdtacixoit with a tagged rogion via a sensing device, the sensing device must be able to see at lcast ote entire tag in its fisld of view no matter wher8 iu the region or at what orientati4u it is positioned. Tha rcquirtl diatneter of tlu field of view of the seasing deviee is tbarefore a fustction of the size aud spaaixtg of the tags, 1.2.3 Tag Structure Figure 5a sbows a tag 4, in the form of tag 726 with four perspective targats 17. The tag 726 represents sixty 4-bit Aeed-Solomon symbols 747, for a total of 240 bits. The tag represents each "one" bit by the presence of a mark 748, refsrred to as a macrodot, and each "zexo" bit by the absenctr af the corres,panding macrodot. Figure Sc shows a squue tiling 728 of nine tags, Gou1aiili.tlg all "one" bits for illustrativa purposes. It. will be noted ftt the perspective targers are desiguad to be shared between arljacaut tags. Figura 5d sfxaws a square titittg of 16 tags and a correspo.pding minimum -tield of vierW 193, which spans the diagonals of two tags.
Using a(1S, 7) ltaed-Solomon code, 112 bits of tag data are xeduudautly cncodcd to produce 240 encoded bits. The four codawords arc iuterieaved spattaIIy within the tag to maximi2e resilience to burst errors. Assuming a 16-bit tag ID as before, this allows a region CY7 ofup to 92 bits.
The data-bearing macrodots 748 of the tag axc designed to not overlap their neighbars, s4 thxt groups of tags eannat produce structures that resamble targets. This also saves ink. The perspective targets allow detection oftha tag, so ftuther targets are not required.
Althou# tlt.e tag may cotttain &u orientatiott featu.re to allow disambigu&tioa of tle four possible orientations of the tag relative to the sensor, the present invention is qonnctued with embedding oridatatiop data in the tag data. For exaniple, the four codewords can be arranged so that aaclt tag orientatioa (in a rotational sense) contains ona codzword placed at that orientation, as shown in Figure 5a, wllere each symbol is 1abQ11ed with the number of its codeword (14) and the positi.on of the syttibol within the cod6word (A-Cl).

Tag deo4ding then consists of decoding one codeword at each rotational orientation. Each codeword cast either contain a single bit indicating wheUier it is the &rst catleword, or two bits indicating which codeword it is. The latter approach has the advantage that if, say, the data content of ouly one codeword is required, then at most two codawords ueed to be decoded to Abtain the desired data. This may ix~ tha case if the region ID is S not expeoted to change witbia a stroke and is thus oaly dgcoded at the start of a strmke. Within a stroke oniy the codewArd cotxtainin.g the tag ID is tlaeu desired. Burthermt'e, siuee the rotation of dxe sepsing device alanges slowly and predictably within a strQlaa, only one codeword typically needs to be decoded per frame.
lt is possible to diapeuse with perspectivc targets altogether a.ad instead.
rely on the data representation being self-re&istering. In t1Xis case each bit value (or mult't-bit value) is typically represented by 10 an explicit glyph, i.e, no bit value is represeated by the absence Qf a glypb. This ensures that the data grid is well-popul:xted, aad thus allows the grid to be reliably ideu"ed and its perspective distortion detected and subsequently carrected during data samplitxg. To alIow tag botuidaries to be deteGted, eaeh tag data mnust contain a marker pattGrn, and these must be redundantly encoded to allow retiable detection. The overhead of such marker pattetxas is similar to t1ao overhead of explicit per'spective targats. Various such schdtnes are 15 descrilaed in the preseut applicants' co-pending PCT application PCT/A.'(701101274 filed 11 Uotober 2001.
Thes urraugement .728 of Figme 5c shows that the square tag 726 caxr be used to fuUy tile or tesselate, i.e. wit#iout gaps or overlap, a plane of tubitrary size.
Although in pra.fert'ed embodimants the taggiag scheuxes described herein encode a single data bit using the presence or absence of a single uuidifferentiatad rrxacro$ot, they can also txse sets of differentiated 20 glypbs to represent single-bit or multi-bit values, such as the sets of glyphs illustrated in the present applicants' co-pend.in$ PCT application PCT/AUOI/Q1274 filed 11 Oetober 2,401.
1.3 THE NETPAGE N1=TV+roRK
In a preforred embodiment, a netpage netvvorlC consists of a distributcd set of netpage page servers 10, tietpage registration servers 11, netpage ]D servers 12, netpage appliGatiop servers 13, natpage 25 publication servsrs 14, Web terminals 75, natpage prinUers 601, and relay devices 44 conua4ted via a network 19 such as the Interact, as sllown in Figure 3.
The netpage registration server 11 is a server which records relationships betwecn usex's, pens, printea, applications and pubtica.tions, and thereby authorizos various network activities. It autltenticates users and acts as a signing proxy on belialf ofautltenticated users in applicatioa transactions. It also provides 30 handwriting recognition services. As described abo-yc, a netpage page servar 10 uxaiutaips persistent information about page descriptions and page instanccs. The netpage network iacludes any nurubcr of page servers, each handling a subset of page instances. Since a pagcs server also maintains user input values for each page instance, clients such as netpage prlttters send petpage input directly to the appropriate page sarver.
Tkus p$ge scrver iAterprets any such input relative to the description of the corresponding page.
A netpage M server 12 alloeates docu.rnent Ii]s 51 on demand, and pravides load-balanciug af page servers via its TD $llocation scheme.
A netpago printer uses the internet Distributed Name Systeem (DNS), or similar, to resotva a notpage page Cq 50 into the network address di the lnetpage page server handling the comspondiug page instance.
A netpage application server 13 is a seiveX which hosts interacCi.vg netfia,ge applications. A
netpage pttblicaticn server 14 is &n application server which publis$es netpage documents to ur3tpage printers.

Netpage servers can be hosted on a variety of network server platforms from manufaotut'ers such as IBM, Hewlett-Paoksrd, and SWa. Multiple netpage servers caa run concurrently on a single host, and a single server can be distributed over a uuulbet' of hosts. Some or all of t)te fupetionality provided by netpage servers, aud in particutar the fiutctionaiity provided by the ID server and the page server, can also be provided directly in a notpagt appliance such as a uetpage=printer, in a computer workstation, or on a local netWork 1.4 THE NETPAGE PRlN'fER
'Ybe netpage printer 601 is an appliance which is registered with the netpage system and priuts netpage documents on deaaand aud via subseription. Each printer has a uniqtle printer ID 62, and is cou.ueoted to the netpage network via a natwork such as the Internet, ideally via a broadband connECtion.
Apart from identity atyd security setGings in non-volatile memory, the netpage printer cantains no persistent storage. As far as a user is oottcerned, "the network is the cotrputer". Netpages function interactively across space and tiame with the help of tbe distributed netpage page serveis 10, independently of particular ncipage printers.
14.
The netpage printer receives subscribed uotpaga documents from netpage publication servers Eacb document is distt'tbuted in two parts: the page layouts, and tha actua!
text and image objects which populate the pages. aacauge of pet=soti$lizatioa, page la.youts are typically specific ta a paXticttlar subson'ber and so are pointcast to the subscriber's priuter via the appr4priate page server. Text and image objects, on the other ba.nd, are typically sharcd with other subscribers, and so are multicast to alI subscribers' printers apd tkie appropriate page seX=vexs.
'1'he p.etpage publication server optimizes the stgmertta.tion of doewnent content inta pointeasts and multicasts. After receiving the poiutcast of a document's paae layouts, the printer knows which multicasts, if auy, to listen to.
Qnce the printer ftas received the completa page layouts aud objects that define the document to be printed, it can print the document.
The printer rasterizes aud prints odd and even pages simultaneously on both sides of the sheet. It contaixts duplexedd print engine oontrollers 760 aud print engines utilizing Meu}jctT"' printheads 350 for this ,pu,rpose.
. . The printing process Cousists of two decoupled stages: rasterization of page descriptiona, and expansion and printing of page images. T'he rasteT image processor (RIP) consists of one or more standard DSPs 757 rium.ing in paralle;. Thc duplexed print engine controllers consist of custom proa<saeors whiCh expand, dither and print page images in 1'eal time, syticbronixed with the operation of the printheads in the Qrint eugines.
priu.ters not enabled for IR printing have the option to print tags using IFt-absozptive black ink, although this restricGS tags to otherwise empty aceas of the page. Although such pages have more limited fiutetionality than IR-printed pages, they are still classed as netpages.
A uormal netpage printer prints netpagta on sheets of paper. More specialised netpage printers may print onto more spocialised stu'faces, such as globes. Each printer st3pports at least one surface type, and sttpporp at least one tag tiling scheme, and htrnce tag =p, for each surface type. The tag ttaap 811 wb.ich describes the tag tiling scheme actually us$d to print a dooument becomes assooiated 'witb tUat doeument so that the doaumettt's tags can be correctly interprcft8d.

Figure 2 shows the ncipagt prixsksr class d.iagram, reflecting - printer-related informatiort mainfained by a xegisCration server 11 on the natpage network.
1.5 THE NETPAGE PEN
T11e active sensing device of the uetpage system is typically a pcu 101, which, using its embedded controller 134, is able to capture and decode IR poaition tags from a page via an image sepsor. The image seqsor is a solid-state device provided with an appropriate filter to pet'tuit sensing at only near-utfrai'ed wave]engths. As dascxibed in uaore detail below, tlus system is able to sense when the n.ib is iri contact with th.e surface, and the pen is able to sepse tags at a sufficient rate to capture human handwriting (i.e. at 200 dpi or gmater and 100 Hz or fasteC). Ittformatioa captured by ft pen is encrypted and wi.reiessly transmitted to the printer (or base station), the printer ar base station interpreting tha data with respect to the (known) page stnlcture.
The prefetx'ed embodiment of the netpage pen operates both as a normal marking ink pen and as a non-tuarldng stylus. The ntar].cing aspect, hpw4ver, is not necessary for using the netpage system as a browsing system, such as when it is used as an Intcrnet interface. Each netpage pen is registered with the ttetpage system aud bas a unique pen A] 61. P'igure 14 shows the netpage pen class diagraux, refleeting pon-relattd inforuaation maintained by a registrakaou servor 1 I on the netpage netwark.
Wbm either nib is in c4ntaat with a netpagc, t.he pen determines its position and orientation relative to the page. Tho ru'b is attae#led to a force sapsor, and the force on the ut'b. is interpreted relative to a threshold to indic&tB whether the pen is "up" or "down". This allows a interactive eletnen.t on the page to be iclicked' by pressing with the pen nib, in order to request, say, information from a network. Furthermore, the force is captured as a carttauuol.ls value to allow, say, ft full dynatnics of a signature to be veri&ed.
The pen determines the position. and orientation of its uib on the netpage by imaging, in the i.u&ared spectrum, an araa 193 of the page in the vicinity of ft nib. It decodds tio nearest tag and computes the position of the nib relative to the tag &om the observed pcrspective distortion on the imaged tag and the known gat+tnetty of the pen optics. Although t2te position resolution of tba tag may be low, because the tag density on the page is inversely proportional to tha tag size, the $djusted position resoltttion is quite high, exceeding the minimum resolution required for accurate handwriting recognition.
Pen actions relative to a netpage are captured as a series of scrokes. A
siroke con.sists of a sequence of time-statxtped pen positions on the page, initiated by a pen-down, event and completed by the subsequent pen-up event. A stroke is also tagged with the page IA 50 of the netpage whenever the page IA
changes, which, under nomzaa circutnstancas, is at ft commencement ofthe st.rake.
Each netpage pen has a cturent se4wtioa 826 associated with it, allowing the user to perfotzn copy and paste operations etc. The selection is titnestazrlped tse allow the system tcy discard it after a def=iaed time periad. The current selection describes a region of a page instance. It consists of the most recent digital ink stroke captured through the pen rclative to the backgroundd area of the page.
It is interpreted in an application-specific manner once it-is subm.itted to &u applieation vIa a selection hyperlutlr activation.
Facli pen has a current nib 824. This is the nib last notif ed by the pen to the systetn. In tkte case of the default netpage pen dsscaed above, either the marlcing black ink nib or the non-markiug stylus nib is current. Each pen also has a cutttut nt-b style 825. 'I'his is the tnb style last associated with the pen by au applir,ation, e.g. in response to the user selecting awlor from a palette. The default nib style is the nib style &ssociaW with the current nib. Strokes capturod through a pen are tagged with the curzent nib style. Wkiea tlw strokes are subsequently reproducet#, thcy are reprodueed in the nib style with which they are tagged.
Whenever the pen is within rauga of a printer with vcbich it can eotnrn.uuicate, the pen slowly flashes its "outine" LEp. When the pen fails to decode a strokts relative to Gt1s pagc, it piomeutarily activates its "error" LED. When the pen sticceeds in decoding a stroke relative to the page, tt momentarily activates its "okõ L$T].
A sequence of captured strokes is refer.fed to as digital ink. Digital ink forms t#>e basis for the digital exchange of dTawiugs and handwriting, or ouli.ue xzcapitiou of handwriting, and for online verification of signatures.
ne peR is wireless and lransmits digital ink to the netpage priuter via a short-range radio link.
The transmittod digital ink is encrypted for privaoy and security and packetized for efficient transmission, but is always flushed on a pen-up bveut to epsure timely handlEag iu the priate;r.
VJhen the pen is out-of-rango of a printer it b4fl'ers digital ink in iuternal memory, which has a capacity of over ten mitiutos of aorltiuuous haadwritiug. W13ea the pen is once again withiu rattge of a printer, it transfers any buffered digital ink.
A pan catt be registered wit1Y any tGmber of printfts, but because 411 state data resides in netpages both oti paper and ou the network, it is largely immaterial which printer a pen is cotnmunicating with at any particular time.
A preferra$ otnbodiment of the pen is described in greater det$il below, with referectce to Figures 6 to 8.
7.6 Nr-'rnAoE iHTERAt 1'tON
'S'he netpage printer 601 receives data ralatittg to a stroke from the pen.
10I wben the pen is used to interact witli a netpage 1. The coded d$ta 3 of the tags 4 is read by the pen when it is used to exeeute a movement, such as a stroke. The d41a allows ths identity of the particular paga aud associated interaetivs element to be deteruiined and au indication of the relative positiordttg of ft pen relative to the page to be obtaiiied. The'indicating data is transmitted to the printer, where it resolvas, via the 13NS, the page ID 50 of the stroke intc the network address of the netpage page sqrver 10 wltie]i maintains the cvrre+spotuiittg page iustaacc 830. IG then transmits the stroke to the page server. If ttze p$ge was recently identif ed in au earlier stroke, then the printer may alreatdy havo t1w address of the relevant page serm in its cache. Each netpags 30 consists of a compact page layout maintained persisteutly by a lietpage page server (w belorv). The page layout refers to objects such as images, fonTs an,d pieces of taxt, typicully stored elsewhere on the uotpaga network When the page server receives the stroke from the pen, it retrievcs the page description to which the stroke applies, and determines which elemeut of the page description the stroke imtersects, It is theu able to interpret the stroko in the aontext of the type of the relevant element.
A"c1iCIC' Is a stroke where the distance and time between the pen down position and the subsaquent pen up position are both less than some small maximuxn, An object which is activated by a click typicaily reqaizes a cl.ick Ga be activated, and acoordittgly, a longer stroke is ignQrqtl. T11e fail.ure of a pen actiQU, such as a "sloppy" click, to register is indicated by the lack of response frum the pen's "ok" LF17.
There a.re t'uvo kinds of input elenvnts in a ttetpage page description:
hyperlitlks and form fields.
Iuput through a form ficld c$n also trigger the activa.tiou of an associated hyperlink.

~ tvF i r14%nF rGn uca~.tur t iury 2.1 PEN MECHANICS
Referring to Figures 6 and 7, the pen, generally desiguated by referenoe numeral 101, includes a housing 102 iu the form of a plastics mouldi.tlg ha'ving walls 103 defuung an iuterior space 104 for inotultitlg the pen cauippnents. The pen top 105 i3 irt operation rotatably mounCed at one cnd 106 of the housing 102. A
semi-transparent cover 107 is secured to the opposite eM 108 of the housing 102. The cover 107 4 also of inoulded plastics, and is formed frasx.t secui-transpareut material in order to enable thn user to view the status of the LED mounted witlwn the housing 102. The cover 107 includes a main part 109 which substantially surrounds the end 108 of the housing 102 and a projecting portioa 110 which projects back from the main pat 109 aud fits within a corresponding slot 111 formod in the wa11s 103 of the housing 102. A cadio antenna 112 is mounted bebitXd tlte projecting portion 110, within the ltousing 102.
Screw threads 113 surrounding an aperhue 1 13A on tho cover 107 are arranged to receivc a metal end piece 114, including corresponding screw tfue$ds 115. The =Ril end piece 114 is removable to enable ink cariridge replacement.
Also mounted wit}hin the cover 107 is a tri-color status Lp,U 116 pu a tlox PCB 117. The antenna 112 is also mounted ort the f(ex PC13 117. The status I-.El] 116 i4 mouutad at the top of the pen 101 for good all-araund visibility.
. The pen can operate both as a normal marking ink pen and as a non-marking stylus. An ink pen cartridge 11$ with uib 119 aud a stylus 120 with stylus nib 121 are mounted side by side within the housing 102. Either the ink cartridge nib 119 or thc stylus nib 121 cari be brouglit forward through open end 122 of the metal end piece 114, by rotation of the pen top 105. Respective slider blocks 123 and 124 ara mounted to the ink eat'tXidge 118 and stylus 120, respectively. A rotatable cam barrel 125 is secured to tho pen top 105 in operaiibn and arranged to rotate therewith. The cam barrel 125 iucludes a cam 126 in the form of a slot 'ocrithin ft walls 181 of the cam barrel. Cam fnllowers 127 and 128 projecting from slider blqcks 123 and 124 fit within the cm slot 126. On rotation of the cam barrel 125, the slider blocks 123 or 124 move relative to each otller to project eitlur tha paq nib 119 or stylus nib 121 out through thc3ltole 122 in the metal end piece 114. The pea 101 ktas three states of operation. By tturti.rxg the top 105 throu.gh 90 steps, the three stutes are:
* stya.tls 120 nib 121 c]Ut + in3c cartridgn 118 rnib 119 out, and -= nE:ither inic cartridge 118 nib 119 out nor stylus 120 nib 121 cut A-second flex PCB 129, is mountsd ou au electronics c}tassis 130 which sits within the lloasing 102. The second flex PCE 129 mowuts an infrared LED 131 for pro'viding infrared radiation for projection onto the surface. An image srnsor 132 is provided mounted on the second flex PCB 129 for receiving reflected radiation from tlae surf'ace. The seeond flex PCB 129 also m.ounts a radio frequency chip 133, which includes an RE transmitter and Rf receiver, apd a controller chip 134 fnr contralliug operation of the pen 1Q1. Au optics hlock 135 (formed from moulded olear plastics) sits within the cover 107 and project9 an infrared beam onto the surface atld receives images onto tlz image sewor 132.
Power supply wires 136 connect the eomponents on the second flex PC13 129 to battery contacts 137 which are mouutCz3 within the cam barrel 125. A te=.i.nstl.. 138 connects to the battery eoutacts 137 and the eam barrel 125. A tluw volt rechargeable battery 139 sits within the cam barrel 125 in eontact with the battery contaets. An induction chsrging coil 140 is mounted about the second flex PCB 129 to enable recharging of tbe battery 139 via n3ducllon. The second flex PCB 129 also utotuits an infrared UD 143 and infrared photodiode 144 for detecti:ng displacemept iax t.he cam barrel 125 when either the stylus 120 or the iuk cartridge 118 is used for writing, in order to enable a deterarination of t'he f=a being applied to the surface by the pen uib 119 or stylus nib 121. 'Xkte l3tphotodiode 144 detects light from the IR LED 143 via reflectors (aot sbown) tnounted 5 aa the slider blocics 123 and 124.
ftubber grip pads 141 and 142 are provided towards the end 108 of the housing 102 to assist gripp~ng dw 1en, 101, and top 105 also includes a clip 142 for clipping the pen 101 to a poclcet, 3.2 PliN COIYTRoW.RR
Tho pau 101 is arranged to deterinine the position of its nib (stylus nib 121 or ink cartridge nib 10 119) by imaging, in the ia&ared spectrv.rn, an area of the surface in the vicinity of Cb.e ru'b. Xt records the location data from the naarest loc2iti4n tag, aud is &rr&nged to ealcula.te the distaztce of the aib 121 or 119 from the location tab utilising optics 135 and controller chip 134. The c4ntroller chip 134 calculates the orientation of the pen and the nib-to-tag distance from the perspective distortiQn observed on the ixnagad tag.
Utilising the Xf chip 133 and aaCenna 112 the pen 101 can transmit the digital ink data (which is 15 encrypted for securi.ty and packaged for efficient tramm.ission) ta the computrug system.
Vi/hen tha pen is in range of a receiver, the digital ink data is transuuitted as it is formecl. When the pen 101 moves out of range, digital ink data is buffered within the pen 10 1 (the pen 101 oircuitry includes a buffer arranged to siore d.igltal ink data for approximately 12 minutes of the pen motion on the surf'aoa) aud can be transmitted lat4r.
20 The controller cliip 134 is mounted on the seaond flex PCB 129 in tlte pext 101. Figure 8 is a block diagram illustrating in more detail the architecture of the controlier chip 134. Pigu;e 8 also shows representations of the RF cllip 133, the image se3nsor 132, the tri-color sta#us LED 116, the IR iUt:trxtination LED 131, the IR force sensor ItFI 143, apd the force sensor photaliodas 144.
The pen controJler chip 134 includes a controlling processor 145. Bus 146 en&blgs the exchange 25 of data between Gompdnents of the controller chip 134. Flash menrory 147 and a 512 KB DRAM 148 am also included. An analog-tca-digital couvert.er 149 is arranged to convert thC
analog signal from the force seasor photodiode 144 to a, digital signal.
An image sensor interEace 152 interfacas with the image sensor 132. A
transceiver controller 153 and base band circuit 154 am also i.ueltuled to interface with am RF ohip 133 wltich includes an RF circuit 30 155 an4 RF re9anatarg and inductors 156 cpnnected to the autarua 112, The coatrolling pracessor 145 captures and decodes lQcation data from tagg &om the surface via the image sensor 132, uxonit4rs the force sepsor pltotodiode 144, controls the lEI)s 116, 131 and 143, and haradles short-range radio communioation via the xadi'o transceiver 153. It is a medium-perfartua.uce (--40MHa) gencral-pwpose 1:t1SC proeessor.
35 The proressar 14S, digital trattsce(ver cotnponeuts (transceiver oontroller 153 auad baseband cirouit 154), image sensor interface 152, flash m=ory 147 and 512KB DRAM 148 are iutGgeate~d 'ui a sixrgle controller ASIC. A.ualog RF compomuts (RF circuit 155 and li.F rosonators aad inductors 156) are providtld in the separate R.F chip-The image sepsor is a CCD or CMOS ima.ge aetasor. pependin,g on tagging sGtierne, it laas a size raugiug from about 100x100 pixels to 200460 pixels. Many miniature CMOS image sensors are.
coianercial3y available, inaluding the N'attonal Semiconductor l90630.

The controller ASIC 134 enters a quiescent state after a period of insctivity whon the pen 101 is not in contact with a surface. It ittcoCporates a dedicated eircuit 150 which monitors the foroe sensor phvtacliode 144 and wakes up the conproller 134 via the power manager 151 on a pen-down event.
The radio tranaceivar communicates in the unlicensed gOOMHz band normaÃly used by cordless S telephones, or alternativeiy in the unlicensed 2.4CirHz indust.rial, seientific and medical (ISM) band, and uses fmquency hopping and collision detection to provide iztterference-free commuuication.
In an altarnative embodiment, the pen incorporates an Infrared Data Assoeiation (IrDA) iutarface for short-range communication with a base statian or n4tpage printer.
In a further embodiment, the pen 101 includes a pair of orthogorral accelerometers inounted in the normal plane of the pen 101 axis. The accelerometers 190 are shown in Figures 7 and 8 in ghost outline.
The provision of the accelerometers etiables this embodiment of the pen 101 to sense qiotion witllout rsforCncc to surface location tags, allowing the location tags to be sampled at a lower rate. Baelt location tag ID can then identify an object of interest rather than a position on the surface. For example, if the object is a user interface input eÃement (e.g. a couunand button), tlxen the tag ID of each location tag within the area of the iztput element oan directly identify the input element.
The accoleraticn .ui,asnred by the aceglerotaeters in each of the x and y directions is integrated with respect to time to produce an instantaneous vslocity aud positiop.
Since tha atarting position of the st.rolce is not Imown, only relativb positions rwithin a stroke are caleulated. Although position iatngration soeunlulates errors in the sen,sed aacaleration, &ecelerorneters typically hav'a high resolutien, 4114 the time duration of a stroke, over which errors accumulate, is short.
3 hIETPAGE MNTER DESCRlF11C1N
317 P'RINTER MECNANICS
The verticalÃy-motmted netpage waApriuter 601 is shown fu.lly assembled in Figara 9. It prints netpagtss ou. .I/e6ter/M sized media using duplexed 8'/a" MemjetT" print angistes 602 and 603, as shown in Figures 10 and 10a. It uses a straight paper path with the papar 644 passit4g through the duplexed print engines 602 and 603 vvhieh print both sides of a sheet sirnultaneousty, in full color and with fall bleed.
An integral binding assembly 605 applies a strip of glua along one edge af each prilftd sheat, allowing it to $dlxere to the previous sheet when pressed against it. This creates a. final bound document 618 which can range in thickness from one sheet to severalhundred sheets.
'1'he replaceable ink c&rtridge 627, shown in Figure 12 coupled with the duplexed print eugiciss, izas bÃadders or chambers for storing &xa.tive, adhesive, and cyan, magenta, yellow, black and infxared iuks_ Thc cartridge also contains a micro ais filter in a base .tnolding. The tuicro air filter interfaces with an air pump 638 inside tbe pruttet via a hose 639. This provides filtered air to ihe printheads ta prevent ingress of tniero particles intQ the MetnaetT"t printbeads 350 which might atherwise clog tke printhead nozzles. By incozpoxatit+.g the air filter within the cartridge, tlle oper;ational life of the filter is effaCtively linked to ttxe life of the Gartridge- The x.uk cartridge is a fa11y recyoÃable product with a capacity for printiug and gluing 3000 pages (1500 sheets).
Referring to p'igure 10, the motorized media pick-Rp roller assembly 626 pushes the top sheet directly from the =dia ttay past a paper seusot on the fust print vn&e 602 into the duplexed MeMjgtTM
40. printhead assoutbly, The two Memjet7M print oalgiues 602 and 603 are uaounted in q.n apposing irY-line sequeutial configtuatian along tb-- straight paptr path. The paper 604 is dr&xvn into th& fwst print engine 602 by integral, powered pick-tip rollers 626. The position and size of the paper 604 is sensed and full bleed prizttang cotnmences. Fixative is priuted siitt43ltaileously to aid drying in the shortest possible time.
The paper exits the .fust MautjetrM print engine 602 through a set of powored exit spike wheels (aligned along the straight paper path),'which act against a rubberixed roller. These spike wheels contact the ,"wet' priirted surFace and continue to feed tbe sheet 604 into the second lvlemjetY'^(print engine 603.
Referring to Figures 10 and 10a, the paper 604 passes from the duplexed print angines 602 and 603 int4 the binder assembly 605. The priuted page passes betwvesen a powca-ad spike whecl axle 670 with a fib" rous suppott roller and auother movable axle with spike whaels and a rno.tuentary actiou glue wheel.l'ha movablo axle/glue assembly 673 is mouuted to a metal support bracket aud it is trausportad forward to iutm,f$ee with tktE powored a.xla 670 via gears by action of a camshaft. A
separate motor powers this camshaft.
The glue wheel asseMbly 673 consists of a par"ly hollovrr axLe 679 witlt a rotating coupling for tha glue supply h4s6 641 fratu tha iuk oarlridga 627, This axle 679 connects to a glue wheel, which absorbs ) 5 $dhesive by eapillary action through radial holes. A. molded hQaaing 682 surrounds the glue wheel, with an opening at the front. Pivoting side moldings and sprung outer doors are attached to tha ua$ta1 bracket and hinge out sideways when thc rest of tlm assembly 673 is thrust forward. This action expQses tha glue wheel through the &an.t of the molded housing 682. Tensioa springs close tlaa $ssambly aud effeotively cap the glue wb.eel during periods of inactivity.
As the sheet 604 passas into the glue wtnrel assembly 673, adhesivc is applied to one vertical edge on tht front side (apart from the first sheet of a docuinent) as it is transported down into the binding assepnbly 605_ 4 paQpUCTTaGt;ilJt;
Automatic identifiaation refers to the use of technologies such as bar codes, mAgnetic stripe cards, smarGcards, and RF transpondess, to (sertii-)atttorpqtically identify objects to data processing systems without ma.uual keying.
For tho purposes of autocaaqc identifiication, a product item is cotrim.ortly ideniifled by a].2-digit Universal Product Code (UPC), encoded machine-readably in the form of a printed bar oode. The pnost common UPC numberiug systeul incorporates a 5Wdigit manufaatur4r number and a 5-digit item nurnber.
Because of its limited precision, a UPC is used to iclentify a class of product rather thau an individual product item. The Uniform Code Council and EAN Intematiobal define and administer the UPC and ralated codes as subsets of the 14-digit Global Trade Item Number (GTIN).
Witltin supply elairz titaaoagewent, th= is considerable interest in expanding or replacing the UPC scheme to allow individual product items to be uniquely identified and thereby iracked_ fudividual item taggiug can reduce "shrinkage" due to lost, stalen or spQileej goods, improve the efficiency of demand-driven manufacturing and supply, faoilitate tiLe pt'of.tling of product usage, and itnprnve tlo customer experience.
There are two main contanders far izldividual item tagging: 9ptiGal tAps in the form of so-called two-dipleusional b4r codes, and radio &aquency idettti_fteation (RFID) tags, For a detailed description of iZFM tags, refer to Klaus Finkenzeller, RPM Handbook, John Wiley & Son (1949), the contents of which are herein imorporated by cross-rCference. QptiGal tags have the edvantage of being inexpeasive, but require opticalline of-sight forreadiag. RFID tags have the advanrage ofs`upporting omnidirect7on4i raadiug, but are comparatively expensive. The presence of uuetal or liquid can seriously ititet~sre t~th R.p~ tag p~o~ce, undermining the emnidireetidnal reading advantage. Passive (reader-porvcrtd) RF1D tags are projected to be priced at 10 cents each ia multi-million quaMties by the end of 2403, and at 5 cents each soon t'hereafler, but this still falls short of the sub-otte-ceut isulustry t'arget for low-price items such as groeery. The read-only uature of rrlost optical tags has also been cited as a disadvantage, sinee status changtss cannot be written to a tag as an item progresses through the supply chaut. T4ocvaver, this disadvantage is znitigated by the fact tbat a re&d-only tag can refer to information maintained dynamically on a network.
The Massachusetts IAStitute of Technology (MIT) Auto-ID Center has developed 4 standard for a 96rbit Electronic Product Code (EPC), coupled with att Tnternet-based Object Namm Sarvice (ONS) and a Product Marki.tp Language (PMh,). t]nce an ]rl'C is scantted or atherwisz obtaiued, it is used to look up, possibly via the ONS, matching product information portably encoded in PML.
The EPC consists of an 8-bit header, a 28-bit EPC xpaxtagex, a 24-bit object class, md a 36-bit serial number. For a detailed description of tha F~PC, t'efer to Btock,D.L., Tha Electronic Product Code (EPG), MIT A.uto-Aa Ccnter (7$uuary 2001), the contents of which aro herein izrcorporated by oross-reference. The Auto-ID
Center has defa-ned a mapping of the CrTIN antp the EPC to demonstxate compatibility between the EPC and eurrent practices Brock, 1].L., Integrading the Blectrortic Producz Code (-FPC) and the Global 7'rade Item Number (G.17N), MIT Aut4-ID
Center (November 2001), the contero of which are herein incorporated by cross-reference. The p:pC is administered by Pi'Cglobal, att 13AN-UCC,joint vcntiue.
:RPCs are technoiogy-neutral aud can be erlooded and carried iu many farrne.
l'1te Auto-ID Center strongly advocates t1he use of low-cost passive RF11:3 taga to carry IEPCs, and has defzned a 64-bit versiolx of tiYe EPC to allow tlu oost of V-ffD tags to be niizr9mi.aod in the short term.
For detailed description of iow-COSt RF1D t$g C(]4i9Cteri8tlCS, rcfOr to Saruta, S., Towards the 5c -Tpg, WT
Auto-M Center (Ncavember 2001), the contents of which are herein incorporated by cross-reference. For a dewriptiotr of a commercially-availaWe )ow-cost passive RFM tag, refer to 915 MHs RFID 2'ag, Alieu.
Technology (2002), the coratmts of which are hereiu incorporated by crass-refdmurc. F'or detailed description of the 64-bit F-PC, xefer to -13rock, D.L., The Compact 0ectrnnic Product Code, M!T .A,uta-M Cer<ter (November 2001), the ooutepts of which are herein incorporated by cross-reference.
' EPCs are intended nat just faX uWque item-level taggiug and t.r$eking, but also for ca.se-fevel &nd pallet-ievel tagging, and for tagging of other logistic units of shipping and transportation such as coatainers and tnaeks. The distributvd PML database records dynauxic retationsl1ips between items and lugher-level containers in the packagiug, sbipping and transportation hiararahy.

4.7 0)ANITA(3GING IN THE SUPPLY t:HA1N
Using an invisible (e.g. infrared) taggin.g schame to uniquely identify a product item has the signifcant advantagC that it allows the entire surface of a produ.ct to be tagged, or a significant portian thereot without impinging on the graphic design of ite product's packaging or labellin.g. Xf the entire product surface is tAgged, then the orientation of the product doesn't atl'ect its ability ta be scanned, i.e. a signifiaant part of the line-of-sight disadvantage of a visible bar coda is elirn.inated.
Furtherruvre, since the tags are small and massively replicated, label damage no longer prevents scannin,g.

Omnilagging, thcn, coa.sists of covering a lurge proportifln of the snrFace of a product itexu with optically-readable invisible t8gs. I:ach omnitag uniquely idantifies the product item on which it appears. The onmitag may dixectly eaCode the product cocle (e.g, EPC) of the item, or tnay encode a sturog&to 1D which in turn idantifies the praduct code via a database loolotp. Each omnitag also optiomIlJ y identifies its own position on the surface of the product item, to provida tha downstreana consumer beuefits of netpage interaetivity described earlier.
Omnitags aKe applisd during product manufaoture axtd/or packaging using digital,printers. These may be add-on infrared printers which pritlt t1t~ omnitags after the text and graphics have been printed by otber means, or integrated color and inii"ared printers which print the omnitags, text and graphics simttltaneously. Digitally-printed text and graphics may iuclude everything on the label or packaging, or tnay consist only of the variable porkoqs, with otlux portions still printed. by other means.
4.2 OMNITAGGING
As shown in Figure 13,=a product's unique item 1T] 215 mAy be seen as a special kind of unique objeot IID 210. The Eteoironio Product Code (EPC) 220 is one emerging standard for at- item W. Au item 1D
typicaiiy consists of a product ID 214 apd a setia.l number 213. The prbdttct fp idep.tifes a class of pxodttct, wbile the sesial number ideniafies a partir;ular instwe af tltat class, i.d.
an individual produot item. The product ID in turn ty.picaAy consists of a manufaoturer number 211 and a produot class number 212. The best-known product ID is the EAN.UCC TJniversal 1'roduot Cod4 (UPC) 221 and its variants.
As shoWn. -ut Fig=ate 14, aa om.njtag 202 encodes a page ID (or region ID) 50 and a trvo-dimensioual (21)) position 86. The region ID identifies tha 3urf&oe region contaiu.ing the tag, and the position identifies the tag's pasition'within the two,dimepsiaual region. Since the stuface in qpest.ion is the surface of a physical product itetn 201, it is useful to define a otw-ta-one mapping between the region ID and the uuique object ID 210, and more specifically tlus iteAa lD 215, of the product item.
Note,ltowever, that the =pping can be ntatty-to-one without compromising the utility of the ampitag: For exatnplc, eaGh panel of a product item's packaging could have a dUereitt region ID 50. CoA'Versely, the amnitag m3y directly encode tha itam lU, in whiclt case the region ID contains the item M, suitably prefixed to decouple item 1D allocatiott rora general aetpage region 11) a11oc$tiost. Note that the ragion ID uniquely distinguishes the corresponding surface region from a11 otber surf&ce rergiops idetttified within the global nztpage systetxt.
'17te itera li7 2( 5 is prcferably thn EPC 220 proposed by the Auto-17a Cent4r, siqae this provides direct compatibility lxtweea omnitags and EPC-canyi.ng ItFZ17 tags.
In k'igure 14 the position 86 is shown as optioual. This is to indicate that rnuclt of the u-slity of the omnitag in the supply chain derives from the rogian fR 50, and the position may be otnitted ifnot desi.tnd for a particular product.
For interoperability with the uetpage system, an omnitag 202 is a n.atpaga tag 4, i.e. it has the logical strpct-u'e, physical layout and semantics pf s netpage tag.
When a uatp$ge sensing device such as the uetpage pen 101 ima.ges and decodes an aftlnitag, it uses the position and orieutation o#'the tag in its field of view and combines this with the position err,04ed in tlW tng to compute its own pttisztion relati've to dle tag. As the sensing device is moved relative to a Hyperlabelled surface region, it is thereby able to traGk its own t#totion relative to the regiozt and generate a set of tixnestamped position samples rept-oseutative of its time-varying path.
When tbe sensing davioe is a pauõ then the path consists of a sequenea of strokes, with each stroke starting when the pen makes contact with the surface, and end%ng whsn the pon breaks contact with the surfaee.
When a stroke is fot'wai'ded to ther page server 10 responsible for the region ID, the strver retrieves a description of the region keyed by region ID, and interprets thPS
stroke in relation to the 5 desctiption. For example, if the desoription includes a hyperlinlc and the strolce intersects the zone of the hyperlink, theri the server may interpret the stroke as a designation of the hyperiink and activate the hyperlink.
4,3 OMNITAG Pf21NTING
An omnitag ptinW is a digital priutet which prints ornttitags onto the label, packaging or actual 1 ~ surfnce of & prbduct befara, during or after product manufacture ancUor assembly. It is a special case of a netpage printer 601. It is capable c,fpt'i#tiug a conppuops pattern of o.uutit$gs onto a surface, tyl,ically using $
near-infrared-absorptive ink. In high-speed environmants, the printer inoludea hardware which accelerates t&g rendering. This typically includes real-time Reed-Salampn encoding of variable tag data such as tag position, and real-time template-based repder.ht.g of the actual tag pattern at the dot resolutian of the priuthead 15 The printer may be an add-on infrared printer which prints tlte omitit$gs after text and graphics have been priuted by other means, or an integrated color and iufrared priatar whioh pririts the ornnitags, text snd graphics sitnultaneously. Digitally-printed texct and graphics may include everything ou the la.bel or packaging, or may consist ouly of the variable portions, with other portions still printed by other means. Thus an orrmitag ptinter with an in&ared and black pxxutiug capability can displape an exispn,g digital printer used 20 for variable data pxiutiug, such as a conventionsl thermal transfer or inljet printer.
For the purposes of ttr, following discussion, any reference to printing onto an item label is intended to iacludc printing onto the itom paalcagi-4g in general, or direetty outo the item surface.
Furthermore, any reference to an. item M 215 is intendcd to include a region ID 50 (or (;aUectaotr of per-panel region ids), or a component theroo 25 The printer is typically contrQUed by a flost computer, which supplies the printer with fixed aud/or variable text and graphics as well as item ids for inclusion iax the omnitags.
Tha host my provide real-time contral over the printer, whereby it pmvides the printer with da.t.a in real time as pris:ting proceeds. As an optimisation, the host rnay provide the printer with fixed data before prirtting begins, and only pravide variable data in real time. The printer may also bc capable of geAerating per-item variable data based on 30 paranreters provided by the host. For example, the host may provide t1m priuter with a base item ID prior to printing, and the printer may simply increznent the base item Yp to genarata succesaive item ids.
Alternatively, memory in the inlt cartridge or other storage medium inserted into the printer may provide a source of unique item ids, in which ease the printer reports the assignnient of itcros ids to the host computer for recording by the host.
35 Alternatively still, the printer m.ay be capable of reading a pre-axistit3g itera ID from the labei onto which the omnitags are being prfnted, assuming the t3nique rp has been applied in some form to the label during a previous manufacturing stap. For example, the item IA may already be preseut izr the form of a visible 21) bsu' code, or encoded in an RF1D tag. In the former cw tJu?
printer can include au optical bar code scanner. In the latter case it can include at- RM reader.

The printer may also be capable of rendering the item ID in other forws. For example, it may be capable of printing the item JD in tht form of a 21) bar code, or of printing t}te product ]D component of the item ID in the form ofa ID bar code, or of writing the item ID to a vcwri.table or- wtitG-once RFID tag.
4.4 OMNITAG SCANNING
Itern information= typically flows to the prodaet server in response to sitaa.ted scan events, e,g.
when an item is scanaed into inventory on delivery; when the item iy placetl on a retail shelf; and when the item is sca"ed at poiut of ml.e. Both fi.xed and hand-held scanners may be used to scau. eM-4itagged produGt items, using both laser-based 2D scanning and 2D imge-sensor-based sca.nning, using similar or the sarxte techniques as employed in the netpage pen.
As shown in Figure 16, both a fixed scaruier 254 and a hand-held scann.er 252 com.nmlwicate scan dats to the ptodttct server 251. The product set'ver mtty in tutu catttixtuuicate prpduot item event data to a peer product server (not shown), or to a product application server 2S0, which may implement sharin$ of data with related produot servers. For exuztple, stock movements within a retail store may be recorded locally on the retail store's product server, but the t=ufactttxer's product server may be notified once a product item is r 5 sold.
4.5 QMhtITAG-RAsrzp Ni=TPAGF- IN'TRRACTIt?NS
A product item whose labelling, packagiltg or actual surface has been omnitaggod provides the same level of istteractivity as itny othar natpage.
There is a strong case to be made for uo"ge-eompatible product tagging.
Netpage turns any priuted yuxface into a fiuely differentiated graphical user interface akin to a WeI3 page, 4Ud tltete axe many applications which map nicely onto te surfaGo of a product. These applications include obtaiuing product iaxformation of various kinds (nutritior4 iuforruation; cooking iustructious;.recipes; related products; usa-by dates; servicing ins,ixta.Ctiosls; rec$]) iiotices); playi g gam.es;
eltterin.g competitians; mauagi#tg owu.ership (registmdon; query, such as in the case of stolen goods; transfer); providiug product feedback; tnessaging;
and indirect device control. If, on tbe other haud, the pi'odpct tagging is undifforontiated, such as in the Case of an undifferentiated 2D barcode or "7D-c4iTied item ID, then the burden of itiformation navigation is traasferred to the infarmation delivery devioe, yv.b.ic$1 may significantly increase the complexity of the user experience or the required sophistication of thc delivery device user interface.
The invention will now be described with refemacs to ttv followinG examples.
However, it wili of caurstl be appreciated that this inventioA may be embod4ed in many other foculs wit#lout depe.rting from the scope of the invention, as dcfinnd in. the accompanying claims.

les A~Irarsnle.7 - &epgrgfnn nrlrydryxlrnall'dura nanif}~j{~j{~yuninetetrasullonic acid 4 HoS02 / \

N
CN Ga(QA4ab r f r ~OR 3046 otsum tJry S020M
-Ga - ---a ~
GN t luenaMeaH i Ss C 2 h I
1 Npr ~, 0.-'^.O ^~roMe N O~OH N ,N N
18D-190 C, 8 h / - ~
/
7"056 soxDH
3 4 quantltauva R = cH~H2OCHzCH2OCHzCH3oMe 5cnomc I

(i) Gallium(III) chloride (5.70 g; 0.032 nIal) was dissolved in anhydrous tohwne (68 mL) under a slow S strealn of nitrogen and then the resuiting solutiori was cooled in ice/water. Sodlum methoxide (25% in methanol; 23.4 mL) was added slowty with stirrin.g causin.g $ thick wli.,ite preeipita* to form. Upon compietion of the addition, the mixture was starre.d at roaM temperature for I
h and then naphthalene-2,3-diearbonittile (22.8 g; 0.128 .pxo1) was added parkionwise, followed, by triethylene glycol monomethyl ether (65 pnX.). The' thick s(urry was distilled for 2 h to remove the methau.ol and toluene. OAce the tolueue had distilied of#; the reaction mixture becme haulogeq.eous aud less viscous md stirrKsd readi-ly. Heating was continued for 3 h at 190 C (internal). The brown/blaclc reaction rnix=e was cooled to 60 C, dllutcd with chlorofaran (150 mL), ttnd filtGrcd under gravity through a sintered glass fuanel. The solid residue was washed with uiore chlorofot'ux (50 mL) and then a futtYter portion (50 mL) vvitla suctioa under reduced pressure. The resultiug dark gtmu solid was theR sequentially was{~ed uudor reduced pressurc with acCtone (2 x SQ mL), DMF (2 x 50 mL), water (2 x 50 mL), acetone (2 x 50 mL), and diethyl ether (2 x 50 mL). The moist solid was air-dried to a dry powder and thcn heated under high vacaum at ccz. 100 C for 1 h to complete the drying process. NaphthaEocyaniztatogalliwn metttoxytrieth.yleneo:eide 3 was obtained as a fine dark greeu powder (23.14 g; 80%), 7l~ (Nlv1P) 770 nm.

(il) N'aphth$1ocy=ix-atog%lliwn methoxytxiethyleneoxide 3(9.38 g; 0.010 mo1) was treated with 30% oleum (47 mL.) by slow additiau via a dropping fannel while cooling in au ice/water batb. under a nitrogen atinosphere. Upon completion of the addition, the reaction mixture was trausfarred to a prehe&tei 'tvader bath at 55 C and stirred at this temperature for 2 h during which time the mixture became a hauwgenoous visoous dark blue salutiau._ Ths stirrcd mactien uxixtu.re was cooled in ast ice/water bath and then 2-propauol(40 mL) was $dded slowly via a dropping funttet. This mixt= was then poured into 2-propanol (100 mL,) using more 2-propatlol (160 mL) to w$skt out the residues &ora the react.iou flask.
1]iethyl ether (100 ut1.,) WO~i then addad to tlie mixture vvhich was then trausfered to a suntcred glass fwincl aud filtered under gravity affording a moist dark brown solid and a yellowlhrowp, filtrate. Tll6 solid was washed sequentially with ether (50 mG), 'acetone/etber (1:1, 1Q0 zufr), and et.her (100 mL) with suction under reduoed pressurc. no resulting solid (13.4 g) aftcr drying under bigh vacttlun was xheti stirred in ethanol/ether (1:3, 100 nl-) for 3 days and then filtered and driod to give the tetirasulfozliG acid 4 as a f= redlbrown solid (12.2 g; 105 /d oi~thtoretxcal yield;
90% purity according to potentiomctric titration). 1II NMCt (deDMSC7) 5 7.97, 8.00 (4H, dd. J 7.6 = J7.e = 7.2 Hz, H7); 8.49 (4H, dcl, J8,7 = 7.2, ,I a,! = 5.7 Hz, H8); 8.84, 8.98 (4H, d, 47 = 7.2 Hz, H6); 10.10, 10.19, 10.25 (4H, d, Jl,$ = 5.7 Hz, H1); 11.13, 11.16 (4H, s, H4).

Dcamnle 2- PreparqfiQl! gj g{r~nzorairtroi WO
The followiug salts werc prepared as deacrihed below.

PyHnt QosS / (Li or Na)O 04aS l C*7 PYH (U or Na)Q
RmH N~OH
o N N ~Q N
S4s0 N
(L.IorNe)p+ 8-sonS 4xAcOH
Pyti~t PYH (I.f orNa)Q

h ~N o's (1 OO;S
Hus~ R
O~a d Q_ N N~,pH H~ N s --~-N

80aG N N N
Oa0 H~CNH

BhNH SO30 C~
N~ NH 9u3NH
7 H i' ',/
YQ
rJ4a~ / ~1,~
N~"`.Jl ~ry N ~ o'O
r N N
Np ~~ \ ! sose H
(a) 7'e rrapyrid in i usi 5 HydroxygaAicun naphthalooyauir~eteArasulfon'rc aoid 4(189 mgs 0.17 mm61) was suspanded in pyridistiehvatez (50:50; 4a)L) and stirred at room temgarat"e for 16 h during which time tbe reaatiort mixture became homogeneous. l;thes'/ethmol (86:14, 35 mh.) was added to precipitute the salt and the secpem$tant liquid was decauted off before etfw/et3ta:qol (83:17, 12 znL) was added with stirrin8.
The solid was filtered off and washed with ether/edmol (54:5(1, 2 x 5rnT,) Qnd ether (2 x 5 ml.). A#ter drying under high sracuum, the Tetrapyridinium salt 5 was obtained as a grgeit powder (136 mg; S6%), iH. NMR
(d6-DMSO) 8 7.78 (8H, dd, J= 6.3, 6.3 Hz, H3', H5'); 7.97, 8.00 (4H, dd, d,,s = J7,e = 7.2 Hz, H7); 8.25 (4H, dd, JR' 7.8, 7.8 Hz, H4');

8.49 (4H, dd, J8.7 = 7.2, J 8, ) = 5.7 Hz, li8); 8.80 (8H, d, J- 7.8 Hz, H2', H6'); 8.84, 8.98 (4H, d, J6,=y = 7.2 Hz, H6); 10.10, 10.19, 10.25 (4T3, d, Ji,B = 5.7 Hz, H1); 11.13, 11.16 (411, s, H4).

(b) Y'etral'cis(I,&rliazabicyclofS.d OJundec-7-eulum) 9- CompQratxve F~xane,ple Hydroxygall'sum naphthalacya.ninetetrasulfotlic acid 4 (348 mg, 0.31 mmol) and 1,8-diaz4bicycloC5.4.0]up4ec-7-ene (DBLi) (306 mg; 2.17 Mnol) wera stirred in rAetb&uol (5 mL) for 20 h at room tempemtiuro during wh.iah time the reuefition rni.}cmta became hornogeueous, The mixtaxre was diluted with ethauoVether (25:75; 20 mL,) aud stirred for 30 min. The supernatant was decanted off, ether (20 ml,) w&s added and the solid was fslteced off, washing with ethanoVetber (SO:SO; 2 x 20 mL), =d etlw (2 x 20 m.mx.). The tetrasrnxqouium salt 9 was obtai.nad as a green powder af3er dryiug under ,high vacuum. (252 mg;
48%). 'H NMR (drDMSO) S 1.1-1_2 (32E1, m, I-13', H4', H5', 1-110'); 2.5 (8I-I, xn, W), 3.0-3.1 (24H, m, H2', H9', Hl l'); 7.97, 8.00 (4H, dd, .1' 7,9 = J7,6 = 7.2 Hz, H7); 8.49 (41f, dd, Ja7 = 7.2, J 4.1 = 5.7 Hz, H8);
8.84, 8.98 (4U, d, 4,7 = 72 Hz, H6); 10.10, 10.19, 10,25 (411, d, Ji,a = 5.7 Hz, H1); 11.13, 11.16 (4H, s, H4).
(c) Terrak~.'s((rll5urtylairsi anium)8 - Compatrarive Example Hydroxygall.ium uaphthalocyaninetetrasulfotlic acid 4(905 mg; 0.81 tnmol) and tributylamine (2.32 xpT-;

9.70 mmol) were si9txe4 ia etlum4l (96%; 5 mL) for 4.75 h at rootn teuiperature during wbieh time the reaction mixture became homogeueous. The solution was dilutod with athor (100 mL), and the precipitated solid was fiTtered off, washin,g with more ether (2 x 25 ml,). Excess arn.ine was reMoved by stixring the solid in tetxs.hydrofacmp/ether (70:30, 40 xqI,) for 2 h and filterirtg off tho solid. The tekaleis(tnbutylxmmonium) salt 8 was dried 7ut4er high 'vacuuirt and obtainad ss a gtroeu powdEr (730 tng; 49%). This salt is sparingly soluble iu water but readily dissalves ia eCha:aol. IH NMR (da-DMSO) S 0.90 (12H, t, J= 7.2 Hz, H4'); 1.34 (8H, sxl, J= 7.5 Hz, H3'); 1.5$ (6H, m, W-' ); 3.03 (6H, bF dd, J= 7.8, 7.8 Hz, H 1'); 7.97, 8.00 (4H, dd, J 1,8 =A6 = 7.2 Hz, H7); 8.49 (4H, dd, .T8,7 = 7.2, J 8,1 = 5.7 Hz, H8); 8.84, 8.98 (4H, d, J6,7 = 7,2 Hz, H6); 10.10, 10.19, 10.25 (4H, d, Ji,s - 5.7 Hz, H1); 11.13, 11.16 (411, a, H4).

(d) Tetraimiduzaliunt 7 Hydroxygallium naphtjalocyaninetetrasulfonic acid 4 (1.40 g; 1.25 mmol) and imida.zolo (0.596 g; 8,75 mmol) were suspencled in metExanaUwB wr (80:20; 17.5 mL) and then the reauIcing g,reen mixture was stirred at room temperature for 2 h, becoming homogeneaus a,fter I h,. Thc solutian was d-ilutcd with diethyl etber (50 mL), stirred for 15 min. and tlien allowed to stand. The supmatant liquid was dcpauted off und tCier#
ether/methanol (50:50; 20 mL) was added with stirring. Thc solid was filtered ofF, washing with cst}~cr/ractb~al (50:50; 3 x 20 mQ Ud ether (2 x 20mL), The solid was tllen suspended in methano]/ether (50:50; 20 mL) and stirred for 3 h. F'iltration auii drying under high vacuum afforded the tetrairuidazolitun salt 7 as a green powder (1.32 g; 76%). 'H NMR (db-DMSO) & 7.61 (81T, br s, H4', H5'); 7.98, 8.02 (4H, dd, J,.g = J7,6 = 7.2 Hz, IP); 8.49 (4H, br m, H8); 8.84, 8.98 (4H, d, J6,7 = 7.2 Hz, H6); 8.91 (4H, br s, 1-T2');
10:10, 10.19, 10.25 (414, d, J, s= 5.7 Hz, H1); 11.13, (4H, br m, H4).

Ezan~ple 3 Preatr+xtlnn ofraks ctndRefl~ctance&Up'{#PfAmmonium Sa~ts A solution of each salt was tnadcs Up in an. iUk vehicle according to Table 1.

component Vehicle A (%w/v) Vehicle -R (%wJv) Vehicle C(%w/v) Ethylena glycol 6 5.45 5.45 Diethyletle glycol 2 1.82 1.82 2-pyrrolidi.uona 5 4.55 4,55 Glycerol 4.5 4.09 4.09 Urea 1 6.36 6.36 Surfyuol (5110/OH) 0.5 0.45 0.45 1,3-propauo4ial 9,00 -ethanol - - 9.00 Watgr 75 68.18 68.18 Table 1Couxpoaitlen of dyeless ink vehicles for sa.i# dcrivetives 5 The resultiug clear groan solutions were printed on Celcast tnatt photoquality inkjet paptr (143 gsrn) on an lJpson C61 iakjet piiatar and then the refloctancos specm were tneasured on a CaXy 5 1JV-vis spectrophotometer. Results ara given iu Table 2.

Fy'ample Compound Iulc ve.hiele Amiue (13) Amine : 4 pKa pH Q-baud (concontration, (h~) ~
4 C (2) bnne 2.8 805 nm 3(a) 5 H(1.36) Pyridine 4:1 5.2 4_6 807 nm 3(d) 7 B (1.5) Tnaidnole 4:1 6.8 6.1 803 nm&
3(o) 8 C(2) 1343N 4:1 crx. 11 6.8 792 nm 3(b) 9 A(2) D&U 4:1 ca. 12 7=7 744, 787 ~b Figure 28; Figuxe 29 10 Table 2 R.elatioAShip between arnine component of istrasulfonate salts, pH
ofiuk made accordizg to Table 1, and position of Q-hanc3 From Table 2, it can be seen that campou.nds 5, and 7, where BH' has a pK, in tlxe xange of 4 to 9 and tb.e pH of the ink Ãotxnulatioa is between 4 and 6.5, the Q-banri of absorption is greater thaal 800 mxt.
15 lYowever, for compounds 8 and 9, where i3H'' has a pIC, greater than 9 and the pH of the ink formulatisan is gre4tea- than 6.5, the Q-band is siguificautly less than 800 am. Accordingly, compounds 5, and 7 are suitable for formulating iuks which are not too adidic to be compo.tible with con.ventional CMYK inJis, and which retain strong absorption in thb cear-TR region above 800 nm.

20 Other amir~ salts of the gQlliurn naphtlutl.oeqarline tetrasulfonate 4 were prepared analogously to those prepared abova itl Exanlples 2(a)-(d), and formulated as 2 mM solutions in ink veliicle A. The resuicing clear green sQlutions were printed on Celcast matt photoqttality inkjet paper (143 gsm) on an Epson C61 inkjet printer and then the refleotance spect.ra were measured on a Cary 5 UV-vis spectrophotometer.
Results are givcit in Table 3.

Example Am.ine (B) Atuirre: 1 Ink velricle Q-band (_=) 3(e) 1,4-diaaabieyclo[2.2_2]octane (DABCO) 4:1 A 802 am 3(f) Triethanolamine 4:1 A 794 nm 3(g) Pipewrqe 4:1 A 794 nm 3(h) Glucosarnine 4:1 A 798, 740 nm 3(i) ~rrbtttylamirzs 1:1 A $05 zlza 3(1) 2-(?-hydraxyetitaxy~s#ltaqole~ 4:1 A 794, 738 nm 3(k) Quinoline 4:1 A 803 uiu 3(l) Triethylauti~e 4:1 A 795 nrxi xnbie 3 Spectroscopic properties of otfter arpulouitUxl salts From Table 3, it can be seen that D.A.BCO au4 quinoline in a stoichiometric ratio of 4:1 providn salts, which can be farmula.wci into inks having acceptablo re.fleotauce spectra. Stronger bases used in ttus same ratio are generally uusuitnble and result in a significant blue-shift.
However, the use of fewer equivalents of a sironger base can still provide inks having red-shifleCl Q-bands, Fx&zttple 3(i) uses tabutylamiue in a ratio of 1:1 and provides a formiifation having a Q-band at 805 nm. By contrast, tributylamine in a ratio of 4:1. (Table 2) provides a forrnulation having a blue-shiftcd Q-banci at 792 nm.
&zamrsI,le 4-Pre4grationod Re&cjanee S,peetra ofIn&I Mth Added Carboxvlate,5'glts Inks accarsiiug to the present invent3on may alao be prepared without isolation of the naphthalocyatune salts, For euuple, the tetrasu.lfouio acid 4 may be formulated in att ink vehicle and the pH adjusted using a suitable base or bufFer, lrxamples 4(a) and 4(b) below describe the prep$r$tion of inks by addition of carboxylate salts in an ink comprising tlte tetrasulfou.ic 4.

(a) Ljthium/sodir+ra aaetute and tetrasulfonic acid 4 The tetrasulfonic acid 4 was made up to 2mM in ilak vehicle B containiug 8m.vL
NaOAn or I.iOAc. This gave & clear grem solution containing 6 (pH 5.1) tltat was printed on Celcast matt photoquality iulget paper (143 gsm). The reflapt.auoe spectt'trm had %,,,. 806 nm for botit sodium and 1itlrium.

(b) ~W:M disoigum salt and teira,srr(fpnic aa'ul 4 '1'he tetrasulfonic acid 4 was made up to 7.5 mM in ink vebicle B onntsining 3 mM
ethyJenedismiaetetraacedc acid (EDTA) disodium salt. This gava a clear green solutiou (pH 3.7) that was printed on Gelcast ruatt pbotoquality inkjet paper (143 gan.t). The reflectance spectrum had X,,,IX 805 ncn.

F.xamn,{e S-PLgparation and Re}kptq{{ae Spe a o fInks Co{I{pd~kg Mixod Salts Inks according to the present itivernion m$y also comprise mixed salts. Mixed salts Way be adwiageous in providing a suitable balanae of properties or fbr tuqing the spectroscopic chaXacteristics of a salt. For example, in Fxatnple 5(b) the dixeot addition of tbrtt dquivaltnts of p-toluenesulfonic acid to the tetrakig(DBUammonium) salt 9 in the ink formulation lowers the pH from 7.7 to 4.0 and sbiftg the Q-band ta 806 nm indicating that protonation of the internal r~eso-nitrogeps lxas taken plaoe.
(a) Tetrasa0'onz'C aGid 4 and tctrakis(tribW(ylammnnfum) sait 8 Solutions of the tetrasulfonio acid 4 and the tetrakis(tributylammonium) salt 8 (2 mM in vehicle C) were mixed in the ratios as shown in Table 4. The resul4Yng cleat green sohstions were prixitad on Calcast matt pkotoquality inkjct papar (143 gsm) with an >;pson C61 inkjot printor and the pH and maximum absorptions were measured.

Tttrasulfonio acid 4/tetralcis(tributytauumonituu) salt $ pH Q-band 1:3 3.6 796 nm 3:1 2.9 807 nm Table 4 Properties of snixad tetrasulfonic acid 4 attd tJle tetrakis(tributylamrnoaium) salt 8 ia'vebiole C
(b) Tctrak~s(I t~fJammonium) sait 9 and irr-toluetreso(fpnk acid The pHilammoitium saGt 9 (26.3 tng, 15.2 mol) and p-toluenesulfonic acid (8.68 mg, 45.6 psuol) were =dissolved i:a ink vehicle H(11.2 mL) to make up $ solution tbat was 1.36 nt1V1 witb respect to the naphttxalocyauine. This gavc a clear grecn solution (pH 4.0) that was prittted on Celeast matt plDtoquality inkjet paper (143 gsm). The reflectance spectraut W 1m, 806 nm (Fil;ure 30).

(a) Imida.zpli'um salt 7 Rnd acetic acid The tttrairaidazolium salt 7 was mada up to 1.5 MM in ink vehicle B cantaining 3 mM acetic acid. This gave a clear grecr.t solution (pH 5. ].) that was printtd ort CelcasC matt photoquality inlget papor (143 gsm).
The retlectance spectraua had 1.. 807 = (Figure 31).

Lxample d -. LiPhifiYS¾ness An bsram 250 W rxIttal halide lamp (klQl-EP 250WIX] 1240) Witlt an isitensity of 17,000 lutnmns, (approximately 70,0001ux) was used to irradiate printed saiaplts positioned at a distance of 9.0 cm from the globe. The industry standard measurement of lightfastriess is the time taken for a sample to fade by 30%
unc9e-r typica! indoer ligkcting cond.i.tions. Typical indoor lighting condit`ions are defined as illuminstion under a lighting intensity of 5001ux for 10 hours per day.

Lightfastuess = Time taken to fade by 30 /a x(70,f}{l0 h3x / 5001ux) x (24 h /
10 kt) = Time taken to fadt by 30 Sa x 336 Galiium naphthalooyaniuetetrasetlfonate salt CaneentTation in ink pH of ink I.ifetime Vehicle (A or B) (niK (ye~) Tetrapyridi~ium 5 1.5 (A.) 4.6 31 Tetraimidazolitun 7 1.5 (B) 6.1 38.5 Tetrahmj.dazolium 7/awtic acid (2 e}quiv) 1.5 (B) 5.1 3s.S
Tetrasulfonic acid 4/lithium aeetate (4 equiv) 2($) $,1 37.3 Tetrasulfonie aeid 4/soditum acetata (4 equiv) 2(13) 5.1 36.5 '1'etresulfouic acid 4/lithiutn acetate (4 equiv) 1.5 (B) 5.1 22,7 Tetrasulfonic acid 4/sodium acetate (4 equiv) 1,5 (B) g,l 21.9 Tetra.kis(DBrTatnmoniutn) 9 2 (A) 7.7 7.9 T'~ir"pBIIauuuonium.) 9/p-TsC-H (3 equiv) 1.36 (B) 4A 17.5 TetraWs(tributylamxtottiutu.) 8 2 (B) 6.8 35.3 TabIe 3 I'rojeoted lifetimes of $mmonintu salts printed an p$per.

All inlcs according to tkw present iuventiop, with a pH in the range of 3.5 to 7, have excellent ligbtfastrtess. By contrast, tha ink proparecl from tekmkis(17B1i3'ammoniunl) 9, having a pH of 7.7, had poar lightfastaoss with a projected lifetime of only 7.9 ye&rs, This surprising result is a furGher advantage of the present invention aud is undorstaad to be a result of the protonated macrocycle being less reactive towards singlet oxygen, F.=mpla 7- aWwasbress Inks were formulatcd from a variety of salta usiag the hik vehicles A, D, C, A
F, H or .I. Ink vehioles A-C were descizbed in Tab1e 1 above. Table 6 holaw describes inlc vehicles I3, F, H anLi i.
Component D(%w/v) F' ( 1ow/v) H( /pw/v) I(4/ow/v) ethylene glycol 5.45 5.45 5.13 5.22 diethylene g1yGo1 1,82 1.8 1.71 1.74 2-pyxrolidi:none 4.55 4.55 4.27 8.70 gly'cerol 4.09 4.10 3,85 3.91 urea 6.36 .
surfytYol (5Ty4/QH) 0.45 0,45 0.43 0.43 1,3-propanediol 9.10 8.5S 830 1,2-hexanedial 5.98 1-prcrpanol 9.00 - -water 74.5 70.1 71.3 Table 7 Composition of dytless ittk vehicles 0zonefas(ucss of inks prjnted on Celcast u.tatt pllotoqualiiy inkaet paper (143 gsm) were tested as follows. TbB printed samples wera axposed to ozone at a conceutratiozt of 1 ppm until the iutenaity $t 810 nm had decreased to 70 /a. 'F' detiotes a firuYl result for samples tha# had reaohed 70p/o- intensixy. Other samples had inftsity >70% during the tcst period and the ozone 1lfetime was eatrapolated from acquired data.

COmpound Formulation Cottcentration (mM) Tn/a Ozone lifetime (y) 9 A 1.36 1,6 (F) 9 1.36 2.3 ~+ 3 eq. TsC}H A 1.36 4,2 (F) 9+3eq.TsOH B 1,36 4.0 4.8(F) 9 A 2.0 7.7 7.7 (F) S A 1.5 5.5 1.6(f) S 13 1.5 4.6 8.2 (F) 8 C 2,0 6.8 12.6 ()~') 8 C 1.36 7.5 5.5 (F) 8 B 1.36 p/a 7.5 (F) 7 13 1.5 6.1 9.8 (F) 7+2eqA.cOH H 1.S 5.1 12,2(F) 7 D 1.S fi.fi 3.5 (F) 7 ~ 1.5 :n/a 15,8 7 I 1.5 n/a 11.1 (F) 7 H 1.5 rala 13,9 (F) 4+ 4 eq imidaz4le ~I 1.5 6.4 4.5 (F) 4 + 16 eq imidazote B 1.5 7,5 2.$ (F) 6(Li+salt) B 1.5 5.3 2.3 (F) Table 8- Ozonefast.ness ofprintcd iu~

.[uks according to the present inventiou were showa, ta have acceptable ozonefastness, in addition to acceptable lightfastqess.
fn copclusion, gallium nap11t1talocyani.ne salts and inlc fortuulations of the present invention are excellent far ase with taetpage and Hyperl6el~' systetus. These dyes and iiD
hs exhibit near-IR absorption abave 800 nm, good solubility in itakjet ink Porrnulstious, ilegligible or low visihility and excellent lightfutreas. Moreover, these dyes cau bo preparet3 in a ihigh-yielding, expedient 4ud efficient synthesis.

Claims (20)

1. An aqueous formulation comprising an IR-absorbing napthalocyanine dye of formula (II):
or a salt form thereof, wherein:
M is Ga(A1);
A1 is an axial ligand selected from -OH, halogen, -OR3, -OC(O)R4 or -O(CH2CH2O)~R e wherein e is an integer from 2 to 10 and R e is H, C1-8 alkyl or C(O)C1-8 alkyl;
R1 and R2 may be the same or different and are selected from hydrogen or C1-12 alkoxy;
R3 is selected from C1-12 alkyl, C5-12 aryl, C5-12 arylalkyl or Si(R x)(R y)(R
z);
R4 is selected from C1-12 alkyl, C5-12 aryl or C5-12 arylalkyl; and R x, R y and R z may be the same or different and are selected from C1-12 alkyl, C5-12 aryl, C5-12 arylalkyl, C1-12 alkoxy, C5-12 aryloxy or C5-12 arylalkoxy;
said formulation having a pH in the range of 3.5 to 7.

2. The formulation of claim 1 having a pH in the range of 4 to 6.5.

3. The formulation of claim 1, wherein said formulation is buffered.

4. The formulation of claim 1 further comprising at least one base B, wherein a conjugate acid BH+ of said at least one base B has a pK4 of between 4 and 9.

5. The formulation of claim 4, wherein a conjugate acid BH+ of said at least one base B has a pK a of between 4.5 and 8.

6. The formulation of claim 4 comprising a nitrogen base, an oxyanion base or mixtures thereof.

7. The formulation of claim 6, wherein said nitrogen base is a nitrogen-containing C5-12 heteroaryl base.

8. The formulation of claim 7, said nitrogen base is imidazole or pyridine.

9. The formulation of claim 6, wherein said oxyanion base is a carboxylate base.

10. The formulation of claim 9, wherein said carboxylate base is of formula R5C(O)O-, wherein R3 is selected from C1-12 alkyl, C5-12 aryl or C5-12 arylalkyl.

11. The formulation of claim 4 comprising a nitrogen base and an oxyanion base.

12. The formulation of claim 1, wherein R1 and R2 are both H.

13. The formulation of claim 1, wherein M is Ga(OH).

14. An inkjet ink comprising a formulation according to claim 1.

15. An inkjet ink comprising a dye according to claim 1, wherein said ink has a .lambda.max of 800 nm or more.

16. An inkjet printer comprising a printhead in fluid communication with at least one ink reservoir, wherein said at least one ink reservoir comprises an inkjet ink according to claim 14.

17. An ink cartridge for an inkjet printer, said ink cartridge comprising an inkjet ink according to claim 14.

18. A substrate having an ink according to claim 14 disposed thereon.

19. A method of enabling entry of data into a computer system via a printed form, the form containing human-readable information and machine-readable coded data, the coded data being indicative of an identity of the form and of a plurality of locations on the form, the method including the steps of:
receiving, in the computer system and from a sensing device, indicating data regarding the identity of the form and a position of the sensing device relative to the form, the sensing device, when placed in an operative position relative to the form, generating the indicating data using at least some of the coded data;
identifying, in the computer system and from the indicating data, at least one field of the form; and interpreting, in the computer system, at least some of the indicating data as it relates to the at least one field, wherein said coded data is printed using an ink according to claim 14.

20. A method of interacting with a product item, the product item having a printed surface containing human-readable information and machine-readable coded data, the coded data being indicative of an identity of the product item, the method including the steps of:
(a) receiving, in the computer system and from a sensing device, indicating data regarding the identity of the product item, the sensing device, when placed in an operative position relative to the product item, generating the indicating data using at least some of the coded data; and (b) identifying, in the computer system and using the indicating data, an interaction relating to the product item, wherein said coded data is printed using an ink according to claim 14.