CA2035867C - Ink supply construction and printing method for drop-on-demand - Google Patents
Ink supply construction and printing method for drop-on-demandInfo
- Publication number
- CA2035867C CA2035867C CA002035867A CA2035867A CA2035867C CA 2035867 C CA2035867 C CA 2035867C CA 002035867 A CA002035867 A CA 002035867A CA 2035867 A CA2035867 A CA 2035867A CA 2035867 C CA2035867 C CA 2035867C
- Authority
- CA
- Canada
- Prior art keywords
- invention defined
- ink
- foam material
- foam
- pores
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
- B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
- B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
- B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
- B41J2/01—Ink jet
- B41J2/17—Ink jet characterised by ink handling
- B41J2/175—Ink supply systems ; Circuit parts therefor
- B41J2/17503—Ink cartridges
- B41J2/17513—Inner structure
Abstract
IMPROVED INK SUPPLY CONSTRUCTION AND PRINTING
METHOD FOR DROP-ON-DEMAND INK JET PRINTING
Abstract A process and apparatus for drop-on-demand ink jet printing utilize the steps of: selectively ejecting ink drops from drop ejection regions through related orifices; feeding ink through capillary feed passages to the drop ejection regions to replace ejected ink drops; and supplying ink to said capillary passages from an innately reticulate foam structure comprising a network of fine, mutually-connected, three-dimensionally branched filaments.
METHOD FOR DROP-ON-DEMAND INK JET PRINTING
Abstract A process and apparatus for drop-on-demand ink jet printing utilize the steps of: selectively ejecting ink drops from drop ejection regions through related orifices; feeding ink through capillary feed passages to the drop ejection regions to replace ejected ink drops; and supplying ink to said capillary passages from an innately reticulate foam structure comprising a network of fine, mutually-connected, three-dimensionally branched filaments.
Description
20~67 IMPROVED INK SUPPLY CONSTRUCTION AND PRINTING
MET~OD FOR DROP-QN-D~MAND INK JET PRINTING
Technical Field The present invention relates to ink jet printing devices of the drop-on-demand kind and, more - specifically, to improved ink supply constructions for such devices.
Background of Invention In drop-on-demand ink jet printers single drops are ejected from an orifice by on-demand actuation of a transducer, most commonly either an electro-mechanical transducer (as used in piezo-electric printers) or an electro-thermal transducer (as used in bubble jet printers). In both of these approaches, it is necessary to reliably contain the ink and refill the drop ejection region after an ink drop has been ejected through the orifice. Refill ink can be supplied from a reservoir integral with the print head (in "print/cartridge embodiments") or, via an umbilical conduit, from a remote reservoir. Usually, a combination of capillary ink feed and atmospheric pressure, transmitted hydraulically, is employed in refilling the drop ejection region. In some prior art systems, further means, e.g. positive pressure ~ources or gravitational forces acting via a hydrostatic head are used instead of, or to supplement, the usual approach. ~owever, such further means are cumbersome, particularly in print/cartridge embodiments, where the desire is for compact insertable units. Thus, ~upplying refill ink via capillary action and transmitted atmospheric pre8sure is most attractive; U.S. Patents 4,095,237 and 4,329,698 provide examples of drop-on-demand ink jet print/cartridges using this approach.
As described in U.S. Patents 4,509,062 and 4,630,758, it is often desirable that the ink supply region be subject to a slight, relatively constant, 203~867 negative pressure (or back-pressure). Such back-pressure prevents ink from drooling, or being easily æhaken, from the orifices, but it should not be so large as to prevent adequate ink refill of the drop ejection zone. To accomplish a controlled - ~- back-pressure the '062 patent suggests a bladder reservoir which exhibits a substantially constant spring force while collapsing. The '758 patent suggests filling the reservoir with a foam-like material that exerts a controlled capillary bac~-pressure. U.S. Patents 3,967,286; 4,095,237 and 4,771,295 also point out the desirability of using a capillary foam material within ink reservoir to prevent introduction of air into the ink path to the print head.
~ owever, there have been certain disadvantages to these prior art approaches. For example, as noted in U.S. Patent 4,794,409, the resilient bladder and foam-reservoir approaches have not utilized the reservoir storage volume efficiently (from the viewpoint of maximizing the percentage of the reservoir 18 interior volume that is available as printable ink). Also, it iB noted that the back-pressure i8 difficult to maintain constant with both prior art techniques and that the specially prepared, "cut and cleaned" foam of the '295 device adds significant cost.
~isclosure of Invention Thus, one important object o$ the present invention is to provide, for drop-on-demand ink jet printing, improved ink reservoir construction which significantly retuce the above-noted problems of prior art devices. One highly useful advantage of the ink reservoirs of the present invention, is their improved efficiency as to maximizing the part of their volume that constitutes suppliable ink.
.
, .
.. . . ..
3 2n3~867 Another advantage of ink reservoirs of the present invention is that they contain foam-like structures having pore sizes that are much more uniform than those of conventional foam materials.
Since the pressure required to extract ink from foam - is inversely proportional to the pore size, a more uniform pore size leads to much more uniform release of ink. Conversely, when the pore size varies widely, some of the pores are so small that it is very difficult to extract the ink they contain, while other pores are so large that they release ink with very little pressure. These variations, which lead to poor utilization of the ink storage volume in the former case, and to "drooling" of ink from the printing mechanism in the latter case, are reduced significantly by the present invention.
Another advantage of preferred embodiments of the present invention is that its foam material is much more chemically inert than the prior art foam material. Prior art materials such as polyurethane foam swell when immersed in water or glycol.
Furthermore, they tend to selectively leach penetrants, dye constituents, and other ink ingredients from the ink, so that ink formulations must be adjusted from the desired printing formulation, to compensate for leached ingredients.
The more inert materials of the present invention significantly reduce these problems.
Another advantage of the reservoirs constructed according to the present invention is that its foam-type materials are much more easily saturated with ink than previously used materials. In prior materials, high vacuum i9 used to urge the ink into the thick walled vesicles of the foam. The advantageous configuration of interconnected thin filaments of foam materials according to the pre6ent - 2û35867 invention do not inhibit penetration of ink, making filling of a reservoir made from such materials a much more simple task in a manufacturing environment.
Another advantage of preferred embodiments of the present invention is that the foam materials -- utilized are hydrophilic, in contraæt with previously used hydrophobic materials, which repel water based ink formulations and frustrate the reservoir filling process.
Another significant advantage of the present invention is its provision of a foam material which requires much less pretreatment (e.g. burning of cell walls and cleaning) prior to incorporation in the ink reservoir.
In one embodiment, the present invention constitutes an improved ink reservoir construction for a drop-on-demand ink jet printing with a print head components of the kind including drop ejection orifices, related drop ejection transducers and pasgage means for containing ink in drop ejection regions proximate the transducers. The ink reservoir comprises a housing defining an ink storage volume and has a vent opening ant an ink outlet fluidly coupled to the print head passage means. A mass of predetermined foam-type material substantially fills a major portion of the housing and covers the ink outlet. The predetermined foam material is a three-dimensional network of very fine filaments that are interconnected 80 as to yield a large void volume comprised of relatively uniform-size interstitial pores. In a preferred embodiment, the foam is innately reticulate 80 as to constitute a purely 8keletal, network formed without membranes in the network intersticies and, in its uncompressed state, is substantially isotropic.
"
' " ' '' : ",. ' .
,:
203~867 In a related aspect, the present invention constitutes a process for drop-on-demand ink jet printing comprising the steps of: (i) selectively ejecting ink drops from a drop ejection region(s) through a related orifice(s); (ii) feeding ink through ~- a capillary feed passage(s) to the drop ejection region(s) to replace ejected ink drops; and ~iii) supplying ink to said capillary passage(s) from a low bulk density foam structure comprising a mass of mutually-connected, three-dimensionally branched we~s. One specifically preferred foam material is an innately reticulate melamine-formaldehyde condensate foam.
Brief Description of Drawings The subsequent description of preferred embodiments refers to the accompanying drawings wherein:
FIG. 1 is a perspective view of a preferred ink jet print/cartridge construction in accord with the present invention;
FIG. 2 is an exploded view of portions of the FIG. 1 print/cartridge;
FIG. 3 is a schematic cross-section of another preferred ink jet print/cartridge construction 25 in accord with the present invention;
FIG. 4 is a cross-sectional view of a print head component structure useful in the FIG. 3 embodiment;
FIG. 5 is a schematic view, partially in cross-section showing another preferred ink jet printing system in accord with the present invention;
FIG. 6 is a cross-sectional view of another preferret print/cartridge construction in accord with the pre 8 ent invention;
FIG. 7 is a scanning electron micrograph of one preferred ink reservoir foam material in accord with the present invention; and .... . ..
, . .
-6- 203~867 FIG. 8 is a scanning electron micrograph at the same magnification as FIG. 7 showing a prior art ink reservoir foam material.
Modes of Carrving Out the Invention s FIG. 1 illustrates one exemplary bubble jet - print/cartridge embodiment incorporating the present invention. The print/cartridge 1 includes an ink reservoir housing comprised of side walls 2, bottom walls 3 and cap assembly 4. The cap assembly can comprise a closure and frame component 6 that is sized to interfit around the top ends of walls 2 of the reservoir and a fluid block component 10 that is constructed to interfit with the inner periphery of frame component 6.
As better shown in FIG. 2 the fluid block component 10 has an outlet passage 13 extending from its outer surface into the ink supply reservoir and an "~" shaped recess 12 formed in the outer surface and coupled to outlet 13. The intermediate portion of recess 12 provides for ink flow to the opposing parallel portions 12a, 12b of the recess.
Also shown in FIG. 2, a trop ejection chip 20 is mounted atop fluid block 10. Chip 20 comprises a dielectric substrate 21 supportin~ a plurality of resistive heater elements 22, selecting electrodes 23, reference electrodes 24 and connection terminals 25.
The heater elements and electrodes can be overcoated with appropriate protective layers. The recess 12 is sized relative to the chip substrate 21 80 that, when chip 20 is mounted on the fluid block component 10, the major portion of recess 12 is covered by the lower 8urface of 8ubstrate 21. However, a part of the opposing recess portions 12a, 12b, remain open to allow ink flow from the reservoir to the edges of the chip 20, - . , . ; . . . .
' ' 2~3~867 An ink barrier and manifold layer 30, e.g. a photo polymer, is formed on the top surfaces of the chip and fluid block to provide an ink barrier fence 31 that ~urrounds the open recess portions 12a, 12b and the resistive heater elements 22 of the chip. A
~- series of baffle walls 32 extend over the surface of chip 20, between recesses 12a, 12b, to separate the individual resistive heater elements 22.
An orifice plate 40 is attached to the barrier and manifold layer 30 and comprises a plurality of orifices 41 formed in a pattern conforming to the pattern of heater elements 22 on chip 20. The orifices 41 are aligned to be located between baffle walls 32 and directly over respective heater elements 22 so that ink bubble formation, caused by heating of a resistive element, will effect drop ejection of ink through its related orifice.
The assembled fluid block component 10 is mounted into frame 6, and electrical leads 8 and connector pads 9 are formed respectively for each of the terminal portions 25 on chip 20. When a print/cartridge is inserted into a printer, the connector pads 9 can be coupled to printer drive circuits to provide for selective firing of the heater elements 22. The print/cartridge fabrication is completed by securing the top cap assembly 4, with all its supported components just described, to reservoir hou8ing 1 which contains a supply of ink contained in a 8haped ma8s of foam material 50 constructed in accord with the teachings of the present invention.
The characteristics of ink reservoir foam materials that are u8eful and preferred, in accord with the pre8ent invention, are described in detail subsequently; however, next several other ink jet printing system constructions in which such foam materials are useful will be described briefly.
.
Thus, referring to FIG. 3, another such print/cartridge 60 compriseæ a main housing with top, bottom an side walls 61, 62, 63 forming an ink supply reservoir. The top wall 61 comprises an air vent opening 64, with an ink-leak closure membrane 65. The ~- bottom wall 62 comprises an ink outlet 66, which can contain a filter member 67, and which supplies ink into the capillary feed passage 68 of the print/cartritge 60. As shown, the feed passage extends across the bottom and up one side of the main housing to a bubble jet print head component, denoted generally P.H.
FIG. 4 illustrates one form in which print head P.~. of FIG. 3 can be constructed. In FIG. 4 the lS edge-shooter bubble jet print head 70 comprises, a base substrate 71 on which is coated a heat control layer 72. A grooved top plate 73 defines a plurality of ink supply channels leading from ink manifold reservoir 75, which i8 coupled to passage 68 of housing 60 (shown in FIG. 3). Located upstream from the orifices 79 and formed between the grooves of top plate 73 and substrate 71, are a plurality of selectively addressable electro-thermal transducers.
These transducers each comprige a discrete resistive heater portion 76, and a discrete address electrode 77. A common electrode 78 can be coupled to the edge of each heater element opposite its address electrode. Formed over both the electrodes and heater elements is a protective layer(s) 74.
FIG. 5 illustrates another ink jet print ~ystem in which the present invention is useful. In thi8 embodiment an ink reservoir 80 is coupled by umbilical 88 to the manifold 75' of a side ~hooter bubble jet print head 70'. In this embodiment print head components similar to the FIG 4 embodiment are indicated by corresponding "primed" numerals. The primary difference in the FIG. 5 print head is that ~ ' " ' ' ' ~"', , --` 2035867 _9_ the top plate comprises separate components which cooperate to provide side ejection passages to orifices 79l. Upon activation current passes through heater 76~ between the address and common electrodes 72l, 78', and ink is heated to eject a drop through the related orifice of plate 79'. The remote ink reservoir 80 is mounted within the printer mainframe (not shown) and comprises a housing having top, bottom and side walls 81, 82, 83. The top wall comprises an air vent ~4 having a liquid blocking membrane 85 and bottom wall 82 comprises an outlet passage 86 coupled to umbilical 88. In accord with the present invention a mass of predetermined foam material 50" is shaped to conform to the interior of the remote ink reservoir and feed ink into umbilical 88.
FIG. 6 illustrates a piezoelectric print cartridge 90, having a housing which is similar to the FIG. 3 tevice. Thus, a reservoir is defined by top, bottom and side walls 91, 92, 93 and has an air vent opening 94, closure 95 and ink outlet opening 96 and filter 97 like the FIG. 3 embodiment. In this embodiment, capillary passage 98 leads to a piezoelectric print head component comprising drop ejection regions 99, each containing an electrostrictive element. Upon selective activations of elements 99 ink drops can be ejected through corresponding orifices 100. Like the EIGS. 1, 3 and 5 embodiments the ink reservoir of the FIG. 6 embodiment, contains a shaped foam mass 50 " ' constructed, as will now be described in detail, in accord with the present invention.
FIG. 7 is a scanning electron micrograph of a material structure I have discovered to be uniquely advantageous for use in ink jet printer supply reservoirs. In general these remarkably improved ink reservoir ~tructures can be described as constituting in their uncompressed condition, a substantially , i~otropic network of very fine filaments that are interconnected so as to yield a large void volume comprised of relatively uniform-size inter~titial pores. The preferred material shown in FIG. 7 is a foam that is innately reticulate so as to have no cell - windows. That is, the foam is a purely skeletal, three-dimensional, network formed without membranes in the network intersticies. In contrast to a mass of unconnected fibers, the three-dimensionally interconnected skeletal filaments of materials according to the present invention, provide and mair.tain uniform interstices to improve ink storage and delivery. In contrast to previous foams that are reticulatet by burning techniques, the materials of the present invention provide a significantly higher void volume, with no blocked, or partially blocked, intersticies and have no residual ~burned-cell-wall~
debris. This results in significant improvements as to the amount of ink that is storable in, and deliverable from given volumes of materials of the present invention.
In comparison to prior art ink reservoir foams (of which FIG. 8 is a "reticulated" polyurethane example), foam-type materials according to the present invention (of which FIG. 7 is a thermoset melamine contensate example) exhibit a number of advantageous tistinctions.
First, in regard to physical structure, materials of the present invention comprise a three-dimensional network of very fine filaments, innately without cell walls. The filaments have a relatively large length to width ratio, e.g. in the order o$ about 10 to 1 or greater.
The innate skeletal nature of foam-type masses of the present invention yields a low bulk den8ity and large void volume because of the high percentage of their volume comprising interstitial voids, In these aspects, the materials can be characterized as having in their utilized condition within the ink reservoir (i.e. uncompressed or compressed condition):
(i) a void volume greater than about 95%, -- preferably greater than about 97% most preferably greater than about 99%; or (ii) a bulk density less than about 1.5 lbs./ft. , preferably less than about l.0 lbs./ft. , most preferably less than about .7 lbs./ft.3.
In regard to pore size, materials according to the present invention can be characterized as having a relatively uniform pore sizes, with a relatively small percentage of voids significantly smaller than the average pore size. More particularly the materials can be characterized as having::
(i) an average pore size in the range of about 25~ to 200~, preferably in the range of about 50~ to 175~, most preferably having a majority of the pores in the size range of about 140~ to 160~; and (ii) a pore 8 ize uniformity such that at least about 95% of the pores have a size larger than .67 times the average pore size, preferably at least about 97.5% of the pores have a size larger than .67 times the average pore size and most preferably at least about 99.5% of the pores have a size larger than .67 times the average pore size, In a most preferred embodiment where the majority of the pores have a size in the range of about 140~ to 160~ it is most preferred that substantially no pores have a diameter less than about 100~ and that the largest pores have a diameter no greater than about 175 microns. Thus, a range of pore -,, '' '' ~. ' ~ ,. .
203~7 sizes no greater than about 75~ yields a highly preferred uniformity in the release of ink from the foam material and a more uniform back-pressure.
In regard to composition of foam materials, it is preferred that such materials be relatively = inert vis a vis the chemicals comprising stored inks and not swell nor leach ingredients from the inks.
One highly preferred group of material, with respect to their cGmposition as well as other aspects described above, are the thermoset foam materials descIibed in U.S. Patent No. 4,540,717 comprising preferably more than ~0% melamine-formaldehyde condensate and most preferably, unmodified thermoset melamine-formaldehyde condensate.
This particularly preferred group of melamine-formaldehyde condensate foams comprise a plurality of mutually connected, three-dimensionally-branched webs (or filaments). As described in the l717 patent the foam structures desirably have:
1. a mean length to width (diameter) ratio in the order of about 10:1 or greater;
and 2. a web or filament density in the order of about 1.10 grams/milliliter or greater, Webs which are too short ~i.e. in which the length to diameter ratio is too low) can decrease the large void volume characteristic preferred for maximizing ink storage.
As pointed out in the '717 patent, the mean length to width (diameter) ratio can be measured microscopically and determined by a statistical counting methods. In such procedure the web length is defined as the distance between the centers of two nodes, and the web width (diameter) is defined as the narrowe8t part of a web, in each case measured on a photomicrograph. The density of the webs is - 203~867 determined by the principle of Archimedes, after placing a foam mass in a suitable liquid, for example isopropanol, with which it becomes fully impregnated by virtue of its open-cell character.
Melamine foams for use in ink reservoirs ~- according to the invention may be melamine formaldehyde condensates, that in addition to melamine, contain up to 50, preferably up to 20, percent by weight of other compounds which form thermosetting resins, and in addition to formaldehyde contain other aldehydes, as co-condensed units.
However, the use of a substantially unmodified melamine-formaldehyde condensate is particularly preferred, because of its high inherent chemical inertness to ink constituents.
The particularly preferred melamine foams according to the invention exhibit an extremely low bulk density, which is very desirable for providing increased void volume for ink storage. When manufactured by the ulra-high-frequency irradiation method described in U.S. Patent No. 4,540,717, such foams can exhibit a bulk density of as little as 1.6[g.1 1].
Melamine foams of the kind described above are manufactured by BASF Aktiengesellschaft, Federal Republic of Germany (BASF Corp., Chemical Div., Parsippany, New Jersey), and sold under the tradename BASOTECT~ by that company and under the tradename WILTEco by Illbruck Schaumstofftechnik, Leverkusen, West Germany (Illbruck USA, Minneapolis, Minn.).
These foams are commonly marketed for heat and sound insulation in buildings, vehicles and larger containers, Other known uses are as shock absorption packaging, bandages, cIeaning materials and 80il treatment~
, ..
;
- 203~86~
I have discovered that the melamine-formaldehyde condensate foams described above perform remarkably in solving the problems heretofore existent in prior art ink jet printing system reservoirs. This is so in part because their substantially isotropic - network of very fine filamentary element6 has substantially completely open cell walls of very uniform size (in comparison to prior art structures).
This provides a superior pore structure and very high void volume for storing ink. Such structure allows more ink storage for a given reservoir volume and provides a more stable ink holding (and back-pressure) characteristic than prior art foam structures used in ink reservoirs. While it is presently preferred to utilize these foam structures in a generally uncompressed state within the reservoirs, compression may be desired in particular applications to adjust structural interstitial spaces, while maintaining the useful or preferred characteristics discussed above.
The superior performance in ink jet reservoirs by foams of the present invention is illustrated by the following results of a test comparing operation of two otherwise identical print/cartridges, one using burned and cleaned polyurethane as described in U.S. ~atent 4,771,295 and as presently used commercially in ink jet print/cartridges and one using the commercially available, acoustic Wiltec~ melamine-based, open cell foam, as described above, in a substantially uncompres8ed state.
Reticulated MelaminePolyurethane Foam _ Foam Pen Weight w/o ink10.02 grams11.52 grams Pen Weight w/ink21.19 grams 21.10 grams Amt. Ink ~Stored"11.17 grams 9.58 grams : Pen Weight Printed "dry" 12.49 grams 14.56 grams Amt. Ink Printed8.70 grams 6.54 grams Volume of Ink Printed (sp. gr. ink=1.102) 7.90 ml 5.94 ml Volume of Pen Body10.21 ml 10.21 ml % of Pen Volume Used 77 % 58 %
Neither foam showed signs of premature starvation when printed continuously at 2KHZ. All jets stopped printing abruptly for both materials.
In addition to its remarkable characteristics in volumetric supply efficiency and superior ink holding capability, the Wiltec~ open cell melamine foam exhibited superior ink compati-bility in comparison to reticulated polyurethane.This is believed to be due not only to the composition of the foam but to its innate reticulate constitution and thermosetting fabrication. Thus, prior art "reticulated" polyurethane foam such as shown in FIG. 8 has partially remaining cell walls and residue remaining from the reticulation burning process. The cell walls and debris have been found to absorb ink components, e.g. surfactant and dye.
This renders print drying and density less desirable. However, foams of the present invention, with their fully open cell wall structure and dense ~keletal filaments do not absorb important ink components to a degree that affects printing. The difference in absorption is observable by comparing the two foams with the same inks. The melamine based .:
-` 203~867 open cell foam indicates no ink pick up and the reticulated polyurethane exhibits a visible yellowish tint.
While the specific melamine based foams described above are particularly preferred for use in -- the reservoirs of ink jet print systems one skilled in the art will appreciate that other ink compatible foam structures comprised of three-dimensionally networked fine filaments and exhibiting low bulk density and substantially completely open cells structure of similar size and uniformity will also be useful. As noted above, foam materials having the desired characteristics described above can be used within ink reservoirs in uncompressed or partially compressed states.
Industrial Applicabilitv The present invention is useful industrially to improve the efficiency of ink storage in ink printing cartridges, while simplifying cartridge filling, enhancing the uniformity of ink supply and reducing adverse interaction with the ink.
MET~OD FOR DROP-QN-D~MAND INK JET PRINTING
Technical Field The present invention relates to ink jet printing devices of the drop-on-demand kind and, more - specifically, to improved ink supply constructions for such devices.
Background of Invention In drop-on-demand ink jet printers single drops are ejected from an orifice by on-demand actuation of a transducer, most commonly either an electro-mechanical transducer (as used in piezo-electric printers) or an electro-thermal transducer (as used in bubble jet printers). In both of these approaches, it is necessary to reliably contain the ink and refill the drop ejection region after an ink drop has been ejected through the orifice. Refill ink can be supplied from a reservoir integral with the print head (in "print/cartridge embodiments") or, via an umbilical conduit, from a remote reservoir. Usually, a combination of capillary ink feed and atmospheric pressure, transmitted hydraulically, is employed in refilling the drop ejection region. In some prior art systems, further means, e.g. positive pressure ~ources or gravitational forces acting via a hydrostatic head are used instead of, or to supplement, the usual approach. ~owever, such further means are cumbersome, particularly in print/cartridge embodiments, where the desire is for compact insertable units. Thus, ~upplying refill ink via capillary action and transmitted atmospheric pre8sure is most attractive; U.S. Patents 4,095,237 and 4,329,698 provide examples of drop-on-demand ink jet print/cartridges using this approach.
As described in U.S. Patents 4,509,062 and 4,630,758, it is often desirable that the ink supply region be subject to a slight, relatively constant, 203~867 negative pressure (or back-pressure). Such back-pressure prevents ink from drooling, or being easily æhaken, from the orifices, but it should not be so large as to prevent adequate ink refill of the drop ejection zone. To accomplish a controlled - ~- back-pressure the '062 patent suggests a bladder reservoir which exhibits a substantially constant spring force while collapsing. The '758 patent suggests filling the reservoir with a foam-like material that exerts a controlled capillary bac~-pressure. U.S. Patents 3,967,286; 4,095,237 and 4,771,295 also point out the desirability of using a capillary foam material within ink reservoir to prevent introduction of air into the ink path to the print head.
~ owever, there have been certain disadvantages to these prior art approaches. For example, as noted in U.S. Patent 4,794,409, the resilient bladder and foam-reservoir approaches have not utilized the reservoir storage volume efficiently (from the viewpoint of maximizing the percentage of the reservoir 18 interior volume that is available as printable ink). Also, it iB noted that the back-pressure i8 difficult to maintain constant with both prior art techniques and that the specially prepared, "cut and cleaned" foam of the '295 device adds significant cost.
~isclosure of Invention Thus, one important object o$ the present invention is to provide, for drop-on-demand ink jet printing, improved ink reservoir construction which significantly retuce the above-noted problems of prior art devices. One highly useful advantage of the ink reservoirs of the present invention, is their improved efficiency as to maximizing the part of their volume that constitutes suppliable ink.
.
, .
.. . . ..
3 2n3~867 Another advantage of ink reservoirs of the present invention is that they contain foam-like structures having pore sizes that are much more uniform than those of conventional foam materials.
Since the pressure required to extract ink from foam - is inversely proportional to the pore size, a more uniform pore size leads to much more uniform release of ink. Conversely, when the pore size varies widely, some of the pores are so small that it is very difficult to extract the ink they contain, while other pores are so large that they release ink with very little pressure. These variations, which lead to poor utilization of the ink storage volume in the former case, and to "drooling" of ink from the printing mechanism in the latter case, are reduced significantly by the present invention.
Another advantage of preferred embodiments of the present invention is that its foam material is much more chemically inert than the prior art foam material. Prior art materials such as polyurethane foam swell when immersed in water or glycol.
Furthermore, they tend to selectively leach penetrants, dye constituents, and other ink ingredients from the ink, so that ink formulations must be adjusted from the desired printing formulation, to compensate for leached ingredients.
The more inert materials of the present invention significantly reduce these problems.
Another advantage of the reservoirs constructed according to the present invention is that its foam-type materials are much more easily saturated with ink than previously used materials. In prior materials, high vacuum i9 used to urge the ink into the thick walled vesicles of the foam. The advantageous configuration of interconnected thin filaments of foam materials according to the pre6ent - 2û35867 invention do not inhibit penetration of ink, making filling of a reservoir made from such materials a much more simple task in a manufacturing environment.
Another advantage of preferred embodiments of the present invention is that the foam materials -- utilized are hydrophilic, in contraæt with previously used hydrophobic materials, which repel water based ink formulations and frustrate the reservoir filling process.
Another significant advantage of the present invention is its provision of a foam material which requires much less pretreatment (e.g. burning of cell walls and cleaning) prior to incorporation in the ink reservoir.
In one embodiment, the present invention constitutes an improved ink reservoir construction for a drop-on-demand ink jet printing with a print head components of the kind including drop ejection orifices, related drop ejection transducers and pasgage means for containing ink in drop ejection regions proximate the transducers. The ink reservoir comprises a housing defining an ink storage volume and has a vent opening ant an ink outlet fluidly coupled to the print head passage means. A mass of predetermined foam-type material substantially fills a major portion of the housing and covers the ink outlet. The predetermined foam material is a three-dimensional network of very fine filaments that are interconnected 80 as to yield a large void volume comprised of relatively uniform-size interstitial pores. In a preferred embodiment, the foam is innately reticulate 80 as to constitute a purely 8keletal, network formed without membranes in the network intersticies and, in its uncompressed state, is substantially isotropic.
"
' " ' '' : ",. ' .
,:
203~867 In a related aspect, the present invention constitutes a process for drop-on-demand ink jet printing comprising the steps of: (i) selectively ejecting ink drops from a drop ejection region(s) through a related orifice(s); (ii) feeding ink through ~- a capillary feed passage(s) to the drop ejection region(s) to replace ejected ink drops; and ~iii) supplying ink to said capillary passage(s) from a low bulk density foam structure comprising a mass of mutually-connected, three-dimensionally branched we~s. One specifically preferred foam material is an innately reticulate melamine-formaldehyde condensate foam.
Brief Description of Drawings The subsequent description of preferred embodiments refers to the accompanying drawings wherein:
FIG. 1 is a perspective view of a preferred ink jet print/cartridge construction in accord with the present invention;
FIG. 2 is an exploded view of portions of the FIG. 1 print/cartridge;
FIG. 3 is a schematic cross-section of another preferred ink jet print/cartridge construction 25 in accord with the present invention;
FIG. 4 is a cross-sectional view of a print head component structure useful in the FIG. 3 embodiment;
FIG. 5 is a schematic view, partially in cross-section showing another preferred ink jet printing system in accord with the present invention;
FIG. 6 is a cross-sectional view of another preferret print/cartridge construction in accord with the pre 8 ent invention;
FIG. 7 is a scanning electron micrograph of one preferred ink reservoir foam material in accord with the present invention; and .... . ..
, . .
-6- 203~867 FIG. 8 is a scanning electron micrograph at the same magnification as FIG. 7 showing a prior art ink reservoir foam material.
Modes of Carrving Out the Invention s FIG. 1 illustrates one exemplary bubble jet - print/cartridge embodiment incorporating the present invention. The print/cartridge 1 includes an ink reservoir housing comprised of side walls 2, bottom walls 3 and cap assembly 4. The cap assembly can comprise a closure and frame component 6 that is sized to interfit around the top ends of walls 2 of the reservoir and a fluid block component 10 that is constructed to interfit with the inner periphery of frame component 6.
As better shown in FIG. 2 the fluid block component 10 has an outlet passage 13 extending from its outer surface into the ink supply reservoir and an "~" shaped recess 12 formed in the outer surface and coupled to outlet 13. The intermediate portion of recess 12 provides for ink flow to the opposing parallel portions 12a, 12b of the recess.
Also shown in FIG. 2, a trop ejection chip 20 is mounted atop fluid block 10. Chip 20 comprises a dielectric substrate 21 supportin~ a plurality of resistive heater elements 22, selecting electrodes 23, reference electrodes 24 and connection terminals 25.
The heater elements and electrodes can be overcoated with appropriate protective layers. The recess 12 is sized relative to the chip substrate 21 80 that, when chip 20 is mounted on the fluid block component 10, the major portion of recess 12 is covered by the lower 8urface of 8ubstrate 21. However, a part of the opposing recess portions 12a, 12b, remain open to allow ink flow from the reservoir to the edges of the chip 20, - . , . ; . . . .
' ' 2~3~867 An ink barrier and manifold layer 30, e.g. a photo polymer, is formed on the top surfaces of the chip and fluid block to provide an ink barrier fence 31 that ~urrounds the open recess portions 12a, 12b and the resistive heater elements 22 of the chip. A
~- series of baffle walls 32 extend over the surface of chip 20, between recesses 12a, 12b, to separate the individual resistive heater elements 22.
An orifice plate 40 is attached to the barrier and manifold layer 30 and comprises a plurality of orifices 41 formed in a pattern conforming to the pattern of heater elements 22 on chip 20. The orifices 41 are aligned to be located between baffle walls 32 and directly over respective heater elements 22 so that ink bubble formation, caused by heating of a resistive element, will effect drop ejection of ink through its related orifice.
The assembled fluid block component 10 is mounted into frame 6, and electrical leads 8 and connector pads 9 are formed respectively for each of the terminal portions 25 on chip 20. When a print/cartridge is inserted into a printer, the connector pads 9 can be coupled to printer drive circuits to provide for selective firing of the heater elements 22. The print/cartridge fabrication is completed by securing the top cap assembly 4, with all its supported components just described, to reservoir hou8ing 1 which contains a supply of ink contained in a 8haped ma8s of foam material 50 constructed in accord with the teachings of the present invention.
The characteristics of ink reservoir foam materials that are u8eful and preferred, in accord with the pre8ent invention, are described in detail subsequently; however, next several other ink jet printing system constructions in which such foam materials are useful will be described briefly.
.
Thus, referring to FIG. 3, another such print/cartridge 60 compriseæ a main housing with top, bottom an side walls 61, 62, 63 forming an ink supply reservoir. The top wall 61 comprises an air vent opening 64, with an ink-leak closure membrane 65. The ~- bottom wall 62 comprises an ink outlet 66, which can contain a filter member 67, and which supplies ink into the capillary feed passage 68 of the print/cartritge 60. As shown, the feed passage extends across the bottom and up one side of the main housing to a bubble jet print head component, denoted generally P.H.
FIG. 4 illustrates one form in which print head P.~. of FIG. 3 can be constructed. In FIG. 4 the lS edge-shooter bubble jet print head 70 comprises, a base substrate 71 on which is coated a heat control layer 72. A grooved top plate 73 defines a plurality of ink supply channels leading from ink manifold reservoir 75, which i8 coupled to passage 68 of housing 60 (shown in FIG. 3). Located upstream from the orifices 79 and formed between the grooves of top plate 73 and substrate 71, are a plurality of selectively addressable electro-thermal transducers.
These transducers each comprige a discrete resistive heater portion 76, and a discrete address electrode 77. A common electrode 78 can be coupled to the edge of each heater element opposite its address electrode. Formed over both the electrodes and heater elements is a protective layer(s) 74.
FIG. 5 illustrates another ink jet print ~ystem in which the present invention is useful. In thi8 embodiment an ink reservoir 80 is coupled by umbilical 88 to the manifold 75' of a side ~hooter bubble jet print head 70'. In this embodiment print head components similar to the FIG 4 embodiment are indicated by corresponding "primed" numerals. The primary difference in the FIG. 5 print head is that ~ ' " ' ' ' ~"', , --` 2035867 _9_ the top plate comprises separate components which cooperate to provide side ejection passages to orifices 79l. Upon activation current passes through heater 76~ between the address and common electrodes 72l, 78', and ink is heated to eject a drop through the related orifice of plate 79'. The remote ink reservoir 80 is mounted within the printer mainframe (not shown) and comprises a housing having top, bottom and side walls 81, 82, 83. The top wall comprises an air vent ~4 having a liquid blocking membrane 85 and bottom wall 82 comprises an outlet passage 86 coupled to umbilical 88. In accord with the present invention a mass of predetermined foam material 50" is shaped to conform to the interior of the remote ink reservoir and feed ink into umbilical 88.
FIG. 6 illustrates a piezoelectric print cartridge 90, having a housing which is similar to the FIG. 3 tevice. Thus, a reservoir is defined by top, bottom and side walls 91, 92, 93 and has an air vent opening 94, closure 95 and ink outlet opening 96 and filter 97 like the FIG. 3 embodiment. In this embodiment, capillary passage 98 leads to a piezoelectric print head component comprising drop ejection regions 99, each containing an electrostrictive element. Upon selective activations of elements 99 ink drops can be ejected through corresponding orifices 100. Like the EIGS. 1, 3 and 5 embodiments the ink reservoir of the FIG. 6 embodiment, contains a shaped foam mass 50 " ' constructed, as will now be described in detail, in accord with the present invention.
FIG. 7 is a scanning electron micrograph of a material structure I have discovered to be uniquely advantageous for use in ink jet printer supply reservoirs. In general these remarkably improved ink reservoir ~tructures can be described as constituting in their uncompressed condition, a substantially , i~otropic network of very fine filaments that are interconnected so as to yield a large void volume comprised of relatively uniform-size inter~titial pores. The preferred material shown in FIG. 7 is a foam that is innately reticulate so as to have no cell - windows. That is, the foam is a purely skeletal, three-dimensional, network formed without membranes in the network intersticies. In contrast to a mass of unconnected fibers, the three-dimensionally interconnected skeletal filaments of materials according to the present invention, provide and mair.tain uniform interstices to improve ink storage and delivery. In contrast to previous foams that are reticulatet by burning techniques, the materials of the present invention provide a significantly higher void volume, with no blocked, or partially blocked, intersticies and have no residual ~burned-cell-wall~
debris. This results in significant improvements as to the amount of ink that is storable in, and deliverable from given volumes of materials of the present invention.
In comparison to prior art ink reservoir foams (of which FIG. 8 is a "reticulated" polyurethane example), foam-type materials according to the present invention (of which FIG. 7 is a thermoset melamine contensate example) exhibit a number of advantageous tistinctions.
First, in regard to physical structure, materials of the present invention comprise a three-dimensional network of very fine filaments, innately without cell walls. The filaments have a relatively large length to width ratio, e.g. in the order o$ about 10 to 1 or greater.
The innate skeletal nature of foam-type masses of the present invention yields a low bulk den8ity and large void volume because of the high percentage of their volume comprising interstitial voids, In these aspects, the materials can be characterized as having in their utilized condition within the ink reservoir (i.e. uncompressed or compressed condition):
(i) a void volume greater than about 95%, -- preferably greater than about 97% most preferably greater than about 99%; or (ii) a bulk density less than about 1.5 lbs./ft. , preferably less than about l.0 lbs./ft. , most preferably less than about .7 lbs./ft.3.
In regard to pore size, materials according to the present invention can be characterized as having a relatively uniform pore sizes, with a relatively small percentage of voids significantly smaller than the average pore size. More particularly the materials can be characterized as having::
(i) an average pore size in the range of about 25~ to 200~, preferably in the range of about 50~ to 175~, most preferably having a majority of the pores in the size range of about 140~ to 160~; and (ii) a pore 8 ize uniformity such that at least about 95% of the pores have a size larger than .67 times the average pore size, preferably at least about 97.5% of the pores have a size larger than .67 times the average pore size and most preferably at least about 99.5% of the pores have a size larger than .67 times the average pore size, In a most preferred embodiment where the majority of the pores have a size in the range of about 140~ to 160~ it is most preferred that substantially no pores have a diameter less than about 100~ and that the largest pores have a diameter no greater than about 175 microns. Thus, a range of pore -,, '' '' ~. ' ~ ,. .
203~7 sizes no greater than about 75~ yields a highly preferred uniformity in the release of ink from the foam material and a more uniform back-pressure.
In regard to composition of foam materials, it is preferred that such materials be relatively = inert vis a vis the chemicals comprising stored inks and not swell nor leach ingredients from the inks.
One highly preferred group of material, with respect to their cGmposition as well as other aspects described above, are the thermoset foam materials descIibed in U.S. Patent No. 4,540,717 comprising preferably more than ~0% melamine-formaldehyde condensate and most preferably, unmodified thermoset melamine-formaldehyde condensate.
This particularly preferred group of melamine-formaldehyde condensate foams comprise a plurality of mutually connected, three-dimensionally-branched webs (or filaments). As described in the l717 patent the foam structures desirably have:
1. a mean length to width (diameter) ratio in the order of about 10:1 or greater;
and 2. a web or filament density in the order of about 1.10 grams/milliliter or greater, Webs which are too short ~i.e. in which the length to diameter ratio is too low) can decrease the large void volume characteristic preferred for maximizing ink storage.
As pointed out in the '717 patent, the mean length to width (diameter) ratio can be measured microscopically and determined by a statistical counting methods. In such procedure the web length is defined as the distance between the centers of two nodes, and the web width (diameter) is defined as the narrowe8t part of a web, in each case measured on a photomicrograph. The density of the webs is - 203~867 determined by the principle of Archimedes, after placing a foam mass in a suitable liquid, for example isopropanol, with which it becomes fully impregnated by virtue of its open-cell character.
Melamine foams for use in ink reservoirs ~- according to the invention may be melamine formaldehyde condensates, that in addition to melamine, contain up to 50, preferably up to 20, percent by weight of other compounds which form thermosetting resins, and in addition to formaldehyde contain other aldehydes, as co-condensed units.
However, the use of a substantially unmodified melamine-formaldehyde condensate is particularly preferred, because of its high inherent chemical inertness to ink constituents.
The particularly preferred melamine foams according to the invention exhibit an extremely low bulk density, which is very desirable for providing increased void volume for ink storage. When manufactured by the ulra-high-frequency irradiation method described in U.S. Patent No. 4,540,717, such foams can exhibit a bulk density of as little as 1.6[g.1 1].
Melamine foams of the kind described above are manufactured by BASF Aktiengesellschaft, Federal Republic of Germany (BASF Corp., Chemical Div., Parsippany, New Jersey), and sold under the tradename BASOTECT~ by that company and under the tradename WILTEco by Illbruck Schaumstofftechnik, Leverkusen, West Germany (Illbruck USA, Minneapolis, Minn.).
These foams are commonly marketed for heat and sound insulation in buildings, vehicles and larger containers, Other known uses are as shock absorption packaging, bandages, cIeaning materials and 80il treatment~
, ..
;
- 203~86~
I have discovered that the melamine-formaldehyde condensate foams described above perform remarkably in solving the problems heretofore existent in prior art ink jet printing system reservoirs. This is so in part because their substantially isotropic - network of very fine filamentary element6 has substantially completely open cell walls of very uniform size (in comparison to prior art structures).
This provides a superior pore structure and very high void volume for storing ink. Such structure allows more ink storage for a given reservoir volume and provides a more stable ink holding (and back-pressure) characteristic than prior art foam structures used in ink reservoirs. While it is presently preferred to utilize these foam structures in a generally uncompressed state within the reservoirs, compression may be desired in particular applications to adjust structural interstitial spaces, while maintaining the useful or preferred characteristics discussed above.
The superior performance in ink jet reservoirs by foams of the present invention is illustrated by the following results of a test comparing operation of two otherwise identical print/cartridges, one using burned and cleaned polyurethane as described in U.S. ~atent 4,771,295 and as presently used commercially in ink jet print/cartridges and one using the commercially available, acoustic Wiltec~ melamine-based, open cell foam, as described above, in a substantially uncompres8ed state.
Reticulated MelaminePolyurethane Foam _ Foam Pen Weight w/o ink10.02 grams11.52 grams Pen Weight w/ink21.19 grams 21.10 grams Amt. Ink ~Stored"11.17 grams 9.58 grams : Pen Weight Printed "dry" 12.49 grams 14.56 grams Amt. Ink Printed8.70 grams 6.54 grams Volume of Ink Printed (sp. gr. ink=1.102) 7.90 ml 5.94 ml Volume of Pen Body10.21 ml 10.21 ml % of Pen Volume Used 77 % 58 %
Neither foam showed signs of premature starvation when printed continuously at 2KHZ. All jets stopped printing abruptly for both materials.
In addition to its remarkable characteristics in volumetric supply efficiency and superior ink holding capability, the Wiltec~ open cell melamine foam exhibited superior ink compati-bility in comparison to reticulated polyurethane.This is believed to be due not only to the composition of the foam but to its innate reticulate constitution and thermosetting fabrication. Thus, prior art "reticulated" polyurethane foam such as shown in FIG. 8 has partially remaining cell walls and residue remaining from the reticulation burning process. The cell walls and debris have been found to absorb ink components, e.g. surfactant and dye.
This renders print drying and density less desirable. However, foams of the present invention, with their fully open cell wall structure and dense ~keletal filaments do not absorb important ink components to a degree that affects printing. The difference in absorption is observable by comparing the two foams with the same inks. The melamine based .:
-` 203~867 open cell foam indicates no ink pick up and the reticulated polyurethane exhibits a visible yellowish tint.
While the specific melamine based foams described above are particularly preferred for use in -- the reservoirs of ink jet print systems one skilled in the art will appreciate that other ink compatible foam structures comprised of three-dimensionally networked fine filaments and exhibiting low bulk density and substantially completely open cells structure of similar size and uniformity will also be useful. As noted above, foam materials having the desired characteristics described above can be used within ink reservoirs in uncompressed or partially compressed states.
Industrial Applicabilitv The present invention is useful industrially to improve the efficiency of ink storage in ink printing cartridges, while simplifying cartridge filling, enhancing the uniformity of ink supply and reducing adverse interaction with the ink.
Claims (36)
1. In a drop-on-demand, ink jet system of the kind having a print head component including orifices, drop ejection transducers and passage means for supplying ink to drop ejection regions proximate said transducers, an improved ink supply reservoir comprising:
(a) a housing defining an ink storage volume and having a vent opening and an ink outlet connected to said passage means;
(b) a mass of foam material occupying a major portion of said housing and covering said ink outlet, said foam comprising a three dimensionally branched network of fine filaments interconnected so as to form a large void volume composed of uniform size interstitial pores.
(a) a housing defining an ink storage volume and having a vent opening and an ink outlet connected to said passage means;
(b) a mass of foam material occupying a major portion of said housing and covering said ink outlet, said foam comprising a three dimensionally branched network of fine filaments interconnected so as to form a large void volume composed of uniform size interstitial pores.
2. The invention defined in claim 1 wherein said foam material is innately reticulate.
3. The invention defined in claim 1 wherein said foam material is a thermoset melamine condensate.
4. The invention defined in claim 1 wherein said foam material, in its utilized state within said housing, has a void volume greater than about 95% of its total volume.
5. The invention defined in claim 1 wherein said foam material, in its uncompressed state, has a bulk density of less than about 1.5 lbs./ft.3.
6. The invention defined in claim 1 wherein said foam network is substantially isotropic in its uncompressed state.
7. The invention defined in claim 1 wherein said foam material, in its uncompressed state, has an average pore size in the range of about 50µ to 175µ.
8. The invention defined in claim 7 wherein the majority of said foam material pores have a size in the range of about 140µ to 160µ.
9. The invention defined in claim 8 wherein said foam material contains substantially no pores with a diameter less than about 100µ.
10. The invention defined in claim 1 wherein said foam material in its uncompressed state has a range in pore size diameters no greater than about 75µ.
11. The invention defined in claim 1 wherein the majority of said pores have a diameter in the range of about 140µ to 160µ and at least about 95%
of the pores have a diameter larger than .67 times the average pore diameter.
of the pores have a diameter larger than .67 times the average pore diameter.
12. The invention defined in claim 1 wherein said foam material filaments have a length to width ratio in the order of about 10 to 1 or greater.
13. The invention defined in claim 1 wherein said foam material contains no cell membranes between filaments.
14. The invention defined in claim 1 wherein said foam material is substantially chemically inert with respect to ink constituents.
15. The invention defined in claim 14 wherein said foam material contains substantially unmodified melamine-formaldehyde condensate that has been thermoset.
16. In a drop-on-demand, ink jet print system of the kind having a print head and ink reservoir means in fluid communication with said print head, the improvement wherein said reservoir means comprises:
(a) a housing defining an ink storage volume and having an ink outlet connected to said print head;
(b) an innately reticulate foam structure substantially filling said housing, said foam structure comprising a plurality of fine, mutually-connected, three-dimensionally branched filaments.
(a) a housing defining an ink storage volume and having an ink outlet connected to said print head;
(b) an innately reticulate foam structure substantially filling said housing, said foam structure comprising a plurality of fine, mutually-connected, three-dimensionally branched filaments.
17. The invention defined in claim 16 wherein said filaments (webs) have a length/width ratio of about 10 to 1 or greater.
18. The invention defined in claim 16 wherein said foam comprises a melamine-formaldehyde condensate.
19. The invention defined in claim 16 wherein said foam contains not less than 80% by weight of melamine-formaldehyde as condensed units.
20. The invention defined in claim 19 wherein said filaments have a density greater than 1.10 g/cm3.
21. The invention defined in claim 16 wherein said foam has a bulk density less than about 1.5 lbs./ft.3.
22. A process for drop-on-demand ink jet printing comprising the steps of:
(a) selectively ejecting ink drops from drop ejection regions through related orifices;
(b) feeding ink through capillary feed passages to the drop ejection regions to replace ejected ink drops; and (c) supplying ink to said capillary passages from foam structure comprising a mass of fine, mutually-connected, three-dimensionally branched filaments.
(a) selectively ejecting ink drops from drop ejection regions through related orifices;
(b) feeding ink through capillary feed passages to the drop ejection regions to replace ejected ink drops; and (c) supplying ink to said capillary passages from foam structure comprising a mass of fine, mutually-connected, three-dimensionally branched filaments.
23. The invention defined in claim 22 wherein said foam material is innately reticulate.
24. The invention defined in claim 22 wherein said foam material is a thermoset melamine condensate.
25. The invention defined in claim 22 wherein said foam material, in its utilized state within said housing, has a void volume greater than about 95% of its total volume.
26. The invention defined in claim 22 wherein said foam material, in its uncompressed state, has a bulk density of less than about 1.5 lbs./ft.3.
27. The invention defined in claim 22 wherein said foam material network is substantially isotropic in its uncompressed state.
28. The invention defined in claim 22 wherein said foam material, in its utilized state, has an average pore size in the range of about 50µ to 175µ.
29. The invention defined in claim 22 wherein the majority of said foam material pores have a size in the range of about 140µ to 160µ.
30. The invention defined in claim 22 wherein said foam material contains substantially no pores with a diameter less than about 100µ.
31. The invention defined in claim 22 wherein said foam material in its uncompressed state has a range in pore size diameters no greater than about 75µ.
32. The invention defined in claim 31 wherein the majority of said pores have a diameter in the range of about 140µ to 160µ and at least about 95% of the pores have a diameter larger than .67 times the average pore diameter.
33. The invention defined in claim 22 wherein said foam material filaments have a length to width ratio of about 10 to 1 or greater.
34. The invention defined in claim 22 wherein said foam material contains no cell membranes between filaments.
35. The invention defined in claim 22 wherein said foam material is substantially chemically inert with respect to ink constituents.
36. The invention defined in claim 35 wherein said foam material contains substantially unmodified melamine-formaldehyde condensate that has been thermoset.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US07/398,580 US4929969A (en) | 1989-08-25 | 1989-08-25 | Ink supply construction and printing method for drop-on-demand ink jet printing |
US398,580 | 1989-08-25 |
Publications (2)
Publication Number | Publication Date |
---|---|
CA2035867A1 CA2035867A1 (en) | 1991-02-26 |
CA2035867C true CA2035867C (en) | 1992-07-07 |
Family
ID=23575919
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CA002035867A Expired - Lifetime CA2035867C (en) | 1989-08-25 | 1990-08-22 | Ink supply construction and printing method for drop-on-demand |
Country Status (6)
Country | Link |
---|---|
US (1) | US4929969A (en) |
EP (1) | EP0440785B1 (en) |
JP (1) | JPH04501392A (en) |
CA (1) | CA2035867C (en) |
DE (1) | DE69027198T2 (en) |
WO (1) | WO1991002652A1 (en) |
Families Citing this family (73)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
SG75790A1 (en) * | 1989-09-18 | 2000-10-24 | Canon Kk | Ink jet head and ink jet recording apparatus |
JP2670464B2 (en) * | 1989-09-18 | 1997-10-29 | キヤノン株式会社 | Recording head cartridge, ink tank, and inkjet device |
US5121132A (en) * | 1989-09-29 | 1992-06-09 | Hewlett-Packard Company | Ink delivery system for printers |
US5317339A (en) * | 1989-10-03 | 1994-05-31 | Siemens Aktiengesellschaft | Printing module for an ink-printing system having an ink storage container with an integrated ink-printing head |
JP2752466B2 (en) * | 1989-10-24 | 1998-05-18 | キヤノン株式会社 | Ink tank, inkjet cartridge, and inkjet apparatus |
US5047790A (en) * | 1990-01-12 | 1991-09-10 | Hewlett-Packard Company | Controlled capillary ink containment for ink-jet pens |
GB2249054B (en) * | 1990-07-10 | 1994-10-19 | Canon Kk | Ink tank,ink jet cartridge having the tank,and ink jet recording apparatus having the cartridge |
US5136305A (en) * | 1990-12-06 | 1992-08-04 | Xerox Corporation | Ink jet printer with ink supply monitoring means |
US5233369A (en) * | 1990-12-27 | 1993-08-03 | Xerox Corporation | Method and apparatus for supplying ink to an ink jet printer |
IT1245065B (en) * | 1991-04-15 | 1994-09-13 | Olivetti & Co Spa | INK DETECTOR DEVICE FOR A LIQUID INK PRINTING ELEMENT |
US5341160A (en) * | 1991-04-17 | 1994-08-23 | Hewlett-Packard Corporation | Valve for ink-jet pen |
JP2543970Y2 (en) * | 1991-06-24 | 1997-08-13 | 株式会社ブリヂストン | Urethane foam filling container |
US5151222A (en) * | 1991-08-26 | 1992-09-29 | Mcdonnell Douglas Corporation | Foam absorber |
US5812165A (en) * | 1991-08-29 | 1998-09-22 | Hewlett-Packard Company | Leak resistant ink-jet pen |
IT1250519B (en) * | 1991-10-10 | 1995-04-08 | Olivetti & Co Spa | DEVICE FOR SUPPLYING THE INK TO AN INK-JET PRINT HEAD AND RELATED SUPPLY METHOD. |
CA2084097A1 (en) * | 1991-12-05 | 1993-06-06 | Richard L. Columbus | Capillary collection devices containing foam for enhanced processing |
IT1259361B (en) * | 1992-03-26 | 1996-03-12 | Olivetti & Co Spa | INK CONTAINER FOR AN INK JET PRINT HEAD |
US5477256A (en) * | 1992-03-27 | 1995-12-19 | Scitex Digital Printing, Inc. | Ink mist filter |
DE4214556A1 (en) * | 1992-04-28 | 1993-11-04 | Mannesmann Ag | ELECTROTHERMIC INK PRINT HEAD |
DE4214555C2 (en) * | 1992-04-28 | 1996-04-25 | Eastman Kodak Co | Electrothermal ink print head |
US5289212A (en) * | 1992-05-19 | 1994-02-22 | Xerox Corporation | Air vent for an ink supply cartridge in a thermal ink-jet printer |
US5491501A (en) * | 1992-05-19 | 1996-02-13 | Xerox Corporation | Medium for ink delivery systems |
US5420625A (en) * | 1992-05-19 | 1995-05-30 | Xerox Corporation | Ink supply system for a thermal ink-jet printer |
US5363134A (en) * | 1992-05-20 | 1994-11-08 | Hewlett-Packard Corporation | Integrated circuit printhead for an ink jet printer including an integrated identification circuit |
JP2962044B2 (en) * | 1992-05-29 | 1999-10-12 | 富士ゼロックス株式会社 | Ink tank, inkjet cartridge, and inkjet recording device |
US5686948A (en) * | 1992-11-12 | 1997-11-11 | Graphic Utilities, Inc. | Method for refilling ink jet cartridges |
EP0839658B1 (en) | 1993-05-13 | 2002-08-07 | Canon Kabushiki Kaisha | Ink tank, head cartridge and ink-jet printing apparatus |
JP3138359B2 (en) * | 1993-05-13 | 2001-02-26 | キヤノン株式会社 | Ink tank, ink tank integrated head cartridge integrally configured with the tank and ink head, ink jet printing apparatus including the ink tank or head cartridge |
US5477255A (en) * | 1993-09-07 | 1995-12-19 | Hewlett Packard Corporation | Ink cartridge system with improved volumetric capacity and method for using the same |
US5786834A (en) * | 1994-01-03 | 1998-07-28 | Xerox Corporation | Method and apparatus for storing and supplying ink to a thermal ink-jet printer |
US5565900A (en) * | 1994-02-04 | 1996-10-15 | Hewlett-Packard Company | Unit print head assembly for ink-jet printing |
US6305786B1 (en) | 1994-02-23 | 2001-10-23 | Hewlett-Packard Company | Unit print head assembly for an ink-jet printer |
DE69506300T2 (en) * | 1994-03-31 | 1999-04-29 | Hewlett Packard Co | Hose system with a customized profile |
CA2153301C (en) | 1994-07-06 | 2001-07-03 | Masahiko Higuma | Ink container, ink jet head having ink container, ink jet apparatus having ink container, and manufacturing method for ink container |
US6196669B1 (en) | 1994-10-31 | 2001-03-06 | Hewlett-Packard Company | High durability pressure control bladder for use in an ink delivery system |
DE69514074T2 (en) * | 1994-10-31 | 2000-04-20 | Hewlett Packard Co | Ink tank with a porous body of approximately the same size |
JPH08207304A (en) * | 1994-11-03 | 1996-08-13 | Xerox Corp | Ink supply cartridge and ink jet printer |
JP3317050B2 (en) * | 1994-11-07 | 2002-08-19 | 富士ゼロックス株式会社 | Printer and ink tank |
US5642144A (en) * | 1994-11-29 | 1997-06-24 | Hewlett-Packard Company | Rechargeable pen for printer |
US5680164A (en) * | 1994-11-29 | 1997-10-21 | Hewlett-Packard Company | Refill method and apparatus for ink cartridge units |
US6179417B1 (en) | 1995-01-04 | 2001-01-30 | Lexmark International, Inc. | Process for reducing blockage in nozzle holes for ink jet printing |
US5501725A (en) * | 1995-03-03 | 1996-03-26 | Hewlett-Packard Company | Method for increasing the stability of non-ionic surfactant-containing ink compositions |
EP0747223B1 (en) * | 1995-06-06 | 2000-09-06 | Lexmark International, Inc. | Ink reservoir with coated open-cell foam |
US5707456A (en) * | 1995-10-19 | 1998-01-13 | Lexmark International, Inc. | Method for treating ink jet foam to remove impurities |
US5700315A (en) * | 1996-02-29 | 1997-12-23 | Hewlett-Packard Company | Anti-outgassing ink composition and method for using the same |
US5892527A (en) * | 1996-04-22 | 1999-04-06 | Lexmark International, Inc. | Ink cartridge with an unfelted foam and method of printing using the same |
US5901425A (en) | 1996-08-27 | 1999-05-11 | Topaz Technologies Inc. | Inkjet print head apparatus |
US6071368A (en) | 1997-01-24 | 2000-06-06 | Hewlett-Packard Co. | Method and apparatus for applying a stable printed image onto a fabric substrate |
US20020030715A1 (en) * | 2000-07-07 | 2002-03-14 | Brother Kogyo Kabushiki Kaisha | Ink jet recording device |
US6045215A (en) * | 1997-08-28 | 2000-04-04 | Hewlett-Packard Company | High durability ink cartridge printhead and method for making the same |
US6155676A (en) * | 1997-10-16 | 2000-12-05 | Hewlett-Packard Company | High-durability rhodium-containing ink cartridge printhead and method for making the same |
US6012807A (en) * | 1998-03-06 | 2000-01-11 | Hewlett-Packard Company | Ink containment unit for use in an ink delivery system |
US6206511B1 (en) * | 1998-06-19 | 2001-03-27 | Lexmark International, Inc. | Multiple-cartridge off-board ink supplies for color ink jet printers |
WO2000005073A1 (en) * | 1998-07-24 | 2000-02-03 | 3Wg, Incorporated | Multiple members acting singularly for retaining fluid |
US6241349B1 (en) | 1999-01-28 | 2001-06-05 | Hewlett-Packard Company | High-durability ink containment unit for use in an ink delivery system |
US6347861B1 (en) | 1999-03-02 | 2002-02-19 | Hewlett-Packard Company | Fluid ejection device having mechanical intercoupling structure embedded within chamber layer |
US6242266B1 (en) | 1999-04-30 | 2001-06-05 | Agilent Technologies Inc. | Preparation of biopolymer arrays |
US6323043B1 (en) * | 1999-04-30 | 2001-11-27 | Agilent Technologies, Inc. | Fabricating biopolymer arrays |
US6247779B1 (en) | 1999-07-30 | 2001-06-19 | Lexmark International, Inc. | Printhead configuration |
US6656740B1 (en) | 2000-10-31 | 2003-12-02 | Agilent Technologies, Inc. | Pressure variation in array fabrication |
US6596785B2 (en) | 2001-07-17 | 2003-07-22 | Foamex L.P. | Ink retaining foam structure |
US6371606B1 (en) | 2001-07-17 | 2002-04-16 | Foamex L.P. | Ink retaining foams |
US6871942B2 (en) * | 2002-04-15 | 2005-03-29 | Timothy R. Emery | Bonding structure and method of making |
US20040070639A1 (en) * | 2002-10-10 | 2004-04-15 | Zerza Wendy L. | Monitoring print performance |
US7111930B2 (en) * | 2004-03-25 | 2006-09-26 | Hewlett-Packard Development Company, L.P. | Fluid supply having a fluid absorbing material |
US7040575B2 (en) * | 2004-03-29 | 2006-05-09 | The Boeing Company | Foam composite insulation for aircraft |
US7372145B2 (en) * | 2005-02-28 | 2008-05-13 | Silverbrook Research Pty Ltd | Bonded assembly having improved adhesive bond strength |
DE102005031851A1 (en) * | 2005-07-06 | 2007-01-18 | Basf Ag | Liquid storage of melamine / formaldehyde foam |
US7328974B2 (en) * | 2005-09-29 | 2008-02-12 | Alex Kuo-Shen Wang | Inkjet printer ink cartridge |
US20070097176A1 (en) | 2005-10-31 | 2007-05-03 | Kenneth Hickey | Orifice plate coated with palladium nickel alloy |
CN101437595B (en) * | 2006-03-28 | 2011-05-04 | 巴斯夫欧洲公司 | Tube filled with an open-cell melamine/formaldehyde resin foam and use as a filter or static mixer |
US8485749B2 (en) | 2009-07-20 | 2013-07-16 | Crayola Llc | Ink delivery systems |
US8491075B2 (en) | 2011-02-09 | 2013-07-23 | Xerox Corporation | Method and apparatus for controlling jetting performance in an inkjet printer |
Family Cites Families (20)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3160596A (en) * | 1961-10-02 | 1964-12-08 | Formica Corp | Wax-containing melamine-formaldehyde foam and process of making same |
US3353994A (en) * | 1964-05-07 | 1967-11-21 | Scott Paper Co | Novel reticulated products |
SE371902B (en) * | 1973-12-28 | 1974-12-02 | Facit Ab | |
US4007142A (en) * | 1974-04-24 | 1977-02-08 | Balm Paints Limited | Amine resin and process |
US4095237A (en) * | 1974-12-26 | 1978-06-13 | Aktiebolaget Electrolux | Ink jet printing head |
US4179027A (en) * | 1978-08-24 | 1979-12-18 | Warren Weisberg | High impact strength partially liquid filled bag |
US4192923A (en) * | 1978-10-27 | 1980-03-11 | Allied Chemical Corporation | Amino resin foam, one-phase solution foam precursor and method of producing foam |
DE3011769A1 (en) * | 1980-03-27 | 1981-10-01 | Basf Ag, 6700 Ludwigshafen | METHOD FOR PRODUCING ELASTIC FOAMS BASED ON A MELAMINE / FORMALDEHYDE CONDENSATION PRODUCT |
US4511678A (en) * | 1979-04-17 | 1985-04-16 | Basf Aktiengesellschaft | Resilient foam based on a melamine-formaldehyde condensate |
DE2940786A1 (en) * | 1979-10-08 | 1981-04-16 | Basf Ag, 6700 Ludwigshafen | METHOD FOR PRODUCING MICROCAPSULES |
DE3020091A1 (en) * | 1980-05-27 | 1981-12-10 | Basf Ag, 6700 Ludwigshafen | METHOD FOR PRODUCING POLYURETHANE FOAMS MODIFIED WITH MELAMINE FORMALDEHYDE PRE-CONDENSENS |
DE3171562D1 (en) * | 1980-06-06 | 1985-09-05 | Epson Corp | Ink supply system for a printer |
US4329698A (en) * | 1980-12-19 | 1982-05-11 | International Business Machines Corporation | Disposable cartridge for ink drop printer |
JPS58142861A (en) * | 1982-02-20 | 1983-08-25 | Minolta Camera Co Ltd | Tank for liquid |
US4509062A (en) * | 1982-11-23 | 1985-04-02 | Hewlett-Packard Company | Ink reservoir with essentially constant negative back pressure |
FR2543536B1 (en) * | 1983-03-28 | 1987-05-15 | Inst Francais Du Petrole | MATERIAL OF HIGH MECHANICAL STRENGTH AND NEARBY DENSITY OF THE UNIT, ITS MANUFACTURE AND ITS USES |
DE3323943A1 (en) * | 1983-07-02 | 1985-01-03 | Basf Ag, 6700 Ludwigshafen | STABILIZED MELAMINE RESIN FOAMS |
DE3534738A1 (en) * | 1985-09-28 | 1987-04-09 | Basf Ag | METHOD FOR PRODUCING ELASTIC MELAMINE FOAMS |
US4771295B1 (en) * | 1986-07-01 | 1995-08-01 | Hewlett Packard Co | Thermal ink jet pen body construction having improved ink storage and feed capability |
US4794409A (en) * | 1987-12-03 | 1988-12-27 | Hewlett-Packard Company | Ink jet pen having improved ink storage and distribution capabilities |
-
1989
- 1989-08-25 US US07/398,580 patent/US4929969A/en not_active Expired - Lifetime
-
1990
- 1990-08-22 DE DE69027198T patent/DE69027198T2/en not_active Expired - Fee Related
- 1990-08-22 CA CA002035867A patent/CA2035867C/en not_active Expired - Lifetime
- 1990-08-22 JP JP2513390A patent/JPH04501392A/en active Pending
- 1990-08-22 WO PCT/US1990/004731 patent/WO1991002652A1/en active IP Right Grant
- 1990-08-22 EP EP90914324A patent/EP0440785B1/en not_active Expired - Lifetime
Also Published As
Publication number | Publication date |
---|---|
EP0440785B1 (en) | 1996-05-29 |
US4929969A (en) | 1990-05-29 |
CA2035867A1 (en) | 1991-02-26 |
DE69027198T2 (en) | 1996-12-19 |
EP0440785A1 (en) | 1991-08-14 |
WO1991002652A1 (en) | 1991-03-07 |
JPH04501392A (en) | 1992-03-12 |
DE69027198D1 (en) | 1996-07-04 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
CA2035867C (en) | Ink supply construction and printing method for drop-on-demand | |
US4771295A (en) | Thermal ink jet pen body construction having improved ink storage and feed capability | |
KR100710974B1 (en) | Ink reservoir for an inkjet printer | |
US5289212A (en) | Air vent for an ink supply cartridge in a thermal ink-jet printer | |
JP2927973B2 (en) | Capillary control ink holding mechanism for inkjet pen | |
US6942326B2 (en) | Ink tank | |
JPH0679882A (en) | Ink container for ink jet printing head | |
EP0641660B1 (en) | Ink cartridge system with improved volumetric capacity and method for using the same | |
US5680164A (en) | Refill method and apparatus for ink cartridge units | |
US6682186B2 (en) | Graded capillarity structures for passive gas management, and methods | |
US8480217B2 (en) | Ink jet cartridge having an ink container comprising two porous materials | |
US20070139491A1 (en) | Fluid storage container | |
CA2631365A1 (en) | Filter/wicking structure for micro-fluid ejection head | |
JP2951818B2 (en) | Replaceable ink cartridge for inkjet | |
US5786834A (en) | Method and apparatus for storing and supplying ink to a thermal ink-jet printer | |
JP3261802B2 (en) | Inkjet cartridge | |
CN117980149A (en) | Bubble stop object for an inkjet printhead | |
CA3232200A1 (en) | A bubble stopper object for an ink-jet print head | |
US20030174191A1 (en) | Multi-chamber ink jet print cartridge and method for manufacturing the same | |
JP2591957C (en) |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
EEER | Examination request | ||
MKLA | Lapsed |