DE3008653A1 - SLOT LIGHTING DEVICE - Google Patents

Description

3 e.g. 1 inspection device

The invention relates to a slot lighting device, those bound for the reproduction of original images with a certain thickness, e.g. books Documents, etc., are suitable in a reproduction apparatus is.

Up to now, the illumination of the slit area of a reproduction device has mostly been achieved by focusing a light source on the slit area. That's already out of the pig. 1 of TIS-PS 3 364-816 known. However, this lighting method has two problems. One is that in spite of the intensive illumination of the slot area there is no uniform illumination of the slot having a certain width, that is to say that, for example, only the central part of the slot width is illuminated strongly and the side parts are less strongly illuminated. This leads to an uneven distribution of luminance. The other problem point is that errors in the manufacture or in the assembly of the individual parts of the lighting device have a strong influence on the luminance distribution in the slot area. V / calibrates Z ₀ B. the hit

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the light source from its normal position the luminance distribution in the slot area changes and thus loses its uniformity. To overcome these disadvantages, for example, US Pat. No. 3,982,116 discloses a mechanism for wide area irradiation of the slit area known by means of a convergent light beam, through which a uniform luminance distribution can be achieved in the slot area. Although with this lighting method a change in position the light source does not exert a great influence on the luminance distribution in the slit area, so is they are not very effective in illuminating original images with a certain thickness, e.g. thick books, etc. The reason for this is that when the thick book is opened and the side to be illuminated is facing is placed at the bottom of the original support table, the Page there, v / o it is bound, lifts off slightly from the original support table, which means that the wide Illumination of the slit area with convergent light beams the bound part of the book only in one narrow area is illuminated.

Generally, the light bundle that illuminates the slit area directly from the light source, and that Light bundle that is projected from the light source directly onto a third deflecting mirror and from there onto the Slit area is reflected, made divergent. In Japanese Patent Application Laid-Open 1Ir. 53-H044 describes a technique in which the direct incident light is taken into account in the luminance distribution in the slot area. In addition to the two direct light bundles mentioned above, there are two further light bundles, namely one light bundle, which emanates from the light source and after the reflection at a lower deflecting mirror the slit area directly illuminated, and a light beam emanating from the light source, which after reflection on a upper deflection mirror and a further reflection on one

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third deflecting mirror illuminates the slit area, the both serve to generate images in the slit area. the Problems with the lighting method for image formation by means of these light bundles are described above.

When illuminating original images with a certain thickness, e.g. thick books, etc., it is desirable that all these four bundles of light, including the direct bundles of light, for wide-area illumination of the slot area are divergent.

The object of the invention is to create a slot lighting device that is used for lighting of original images with a certain thickness, e.g. books, etc., is suitable and which can be relocated a light source.

This task is done with

With the aid of a device structure, a light beam reflected from a lower deflecting mirror partially surrounding the light source is made to diverge obliquely from below to illuminate the slit area, while a light beam reflected from an upper deflecting mirror partially surrounding the light source converges before reaching a third deflecting mirror, on reaching the third deflection mirror is reflected by this and as a divergent light bundle, the slit area is illuminated obliquely from below symmetrically to the reflected light bundle from the lower deflection mirror, the symmetrical "illuminating light bundles" mutually within a desired area in the direction of the depth, the perpendicular aligned with the slot area, overlap.

The invention is explained below on the basis of exemplary embodiments with reference to the drawing

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explained in more detail.

Pig. 1 is a schematic representation of a first embodiment of the slot illuminating device;

Fig. 2 is a schematic representation of a second embodiment of the slit lighting device;

Pig. 3 is a schematic representation of a Reproduction device with a built-in slot illumination device.

A permanently installed lens 1 forms a point A according to FIG. 1 on a template support surface 6 at a point 13 on a moving photosensitive body 2. When the original image support surface 6 is moved in the direction indicated by the arrow, the original image is slit-projected onto the photosensitive body 2 moving in the direction indicated by the arrow.

The lens 1 is a facet eye system as shown in FIG of US patent application 889,404 is described, consisting of a lens whose length in the direction of its optical Axis large compared with the <- ft, - "insend diameter is (it will be infacht in the following. 'vi-i Called "rod lens"), or from a short focal length imaging element arrangement, e.g. a light-converging optical facer (available under the trade designation "GeIfock"), which is disclosed in U.S. Pat 3,584,952 and US Pat. No. 3,658,407 and their index of refraction from their center to the edge regions decreases radially and parabolically. The resulting image is that of an image-erecting system. 3 refers to a filament that is part of a light source. 4 denotes an incandescent lamp that serves as a light source and is usually see-through. In another embodiment, the surface of the incandescent lamp

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be designed as a matt surface, the surface being made in a milky brown for light scattering. If the surface of the incandescent lamp 4 is transparent, the light source becomes a point light source in cross section. If the incandescent lamp has a matt surface, the light source thus becomes a uniform light source with the size of the G-liüilanipe 4. A lower deflecting mirror 5 consists of a large number of mirrors with a flat surface, v / whether the ones hit by the IC) ! points the mirror with a flat surface has a cylindrical shape with an elliptical curvature. The first focal point of this enveloping ellipse is at the location of the filament 3> the second focal point is at the point Λ of the original image 6 of the lower deflecting mirror 5 are therefore collected at point A. However, since the lower deflecting mirror 5 consists of a large number of mirrors with a flat surface, the light bundles reflected by the mirrors with a flat surface illuminate the slit area as diverging light bundles without being convergent . The divergent light bundles of each individual mirror with a flat surface therefore overall overlap in an area 7 which is wider than the slit width 8, as a result of which the luminance distribution in the slit width 8 becomes uniform in the area 7. which is wider than the width of the slot with the point A as the center point. The slot width 8 ^ Q is the width that must be illuminated on the original image. It was mentioned above that the enveloping elliptical surface touches the hit points of the mirror with a flat surface; however, the envelope surface can also run through any other point on each of the mirrors with a flat surface. & xn upper deflecting mirror 9 consists of a part of the ellipse and has its first focal point at the location of the filament 3 and its second focal point at a point 10, which

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in front of a third deflecting mirror 11 located in the Lielrtv / eg is located. All light rays emitted by the filament 3 and reflected by the upper deflecting mirror 9 converge at point 10. Point 10, the second focal point can therefore be located directly on the upper optical axis of the lens 1. The third deflection mirror 11 is a mirror having a cylindrical surface and is in the shape of a part of a in cross section Circle. The rays reflected by the upper deflecting mirror 9 converge at the point 10 and then hit as divergent light rays on the third deflecting mirror 11. By the reflection of the divergent light bundle at the third deflecting mirror 11 is reduced Divergence angle to some extent and the reflected light rays substantially illuminate the entire area of the area 7 with the point A on the template support surface 6 in the putty, whereby a results in uniform luminance distribution in the slot area. In this way, an area of the original platen becomes 6, which is wider than the slit width 8, is irradiated obliquely from both sides of the optical axis.

The size of the reflective area and the reflectivity of the deflecting mirror 5 below, des above the deflecting mirror 9 and the third deflecting mirror can be set up in such a way that the luminances of the light bundles that are inclined from both sides of the optical Axis 12 incident on the Gchlitzbereich, are mutually and essentially equal in amount. the The surface of the third deflection mirror 11 can also be made flat instead of being cylindrical. In this In this case, the divergence angle of the light beam remains before and after the reflection at the third deflecting mirror 11 the same. Deflecting mirrors 13 and 14 are mirrors with a cylindrical surface that returns the light rays emanating from the light source to it reflect. They are also auxiliary mirrors for

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effective use of the amount of light and for warming up the light source.

15 "denotes a hit protection or V-head length selection filter, 16 a pre-exposure mirror, 17 and 18 mirrors for exposure of the entire surface steps in the procedure described in the following text. 19 is a pre-exposure light bundle, 20 is a blank exposure light bundle and 21 a totally popular light bundle. . As the original platen 6 is irradiated from both sides of the optical axis 12 in a desired radiation width, that is in an area that is wider than the slit width 8, the illumination width can be substantially constant size can be maintained, even if there are errors in the manufacture of the lower deflecting mirror 5, the upper deflecting mirror 9 and the third deflecting mirror 11 are present, or if the relative position between the lower deflecting mirror 5 or the upper deflecting mirror 9 and the light source of the ITormals division deviates. This means that a sufficiently uniform lighting can always be achieved with a desired Slot width 8 can be achieved, v / obei only shifted the position on the template support surface 6 to the right or left is. Furthermore, both the bundle of light that is emitted by the light source are on the upper deflecting mirror 9 and further is reflected on the third deflecting mirror 11 and falls on the slit area than also the bundle of light emitted by the light source

™ det is and after the reflection at the lower deflecting mirror 5 falls directly on the slit area, divergent light bundles and thus particularly suitable for illuminating original images with a certain thickness, for example books, etc. Effective lighting can therefore be achieved without the original showing undesirable shadows on the bound area of the book.

In the following a second exemplary embodiment is 030037/0842

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explained with reference to FIG. This second embodiment differs from the first only with regard to the lower deflecting mirror. 5 'identifies the lower deflecting mirror, the shape of which is a Part of an ellipse whose first focal point in the Hitte of the light source and whose second focal point corresponds at point 10 'in front of the slit area lying in the light path ^ lies. With the light beam emanating from the filament 3 and impinging on the lower deflecting mirror 5 ' converge in runlet 10 ', then become divergent Bundles of light and illuminate the slit area in an area that is larger than the width of the slit is the point A on the document support surface 6 as the center, whereby a uniform luminance distribution is reached in the slot width 8. The effect of the wide lighting with divergent bundles of light is identical to that already explained with reference to the first exemplary embodiment.

In the following, with reference to FIG. 3, explanations of a method are given in which the device is used in a reproduction device.

The moving photosensitive member 2 consists, from the outside to the inside, ^ u, a * '~ ine o> - ■' "'- ^ igen Insulating layer, a photoconductive ^ - '' iu.i'iiid an electrically conductive base layer.

The moving photosensitive member 2 is given a uniform electric charge on its surface through a corona discharger 22, the polarity of which is positive (+) when the photoconductive body is an N-type semiconductor, and negative (-) if the

photoconductive body is a P-type semiconductor. 35

Then, the moving photosensitive member 2 is subjected to an image exposure through the lens 1 and at the same time a discharge process by a

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] ', Wechsel trom-7.orona discharger 23 (or a corona discharger, whose polarity is opposite to that of the corona discharger 22), creating a charge pattern is created on the calibrated "moving light-sensitive member 2, that corresponds to the light image of the original. Then, the "moving photosensitive member 2 a uniform total exposure on its entire surface exposed by the total exposure light beam, creating an electrostatic latent image with sufficient image contrast is created. The latent image thus produced is processed by a developing device 24 in cascade, iiagnet brush or other execution developed into a toner image. Thereupon the toner image is transferred to image folding paper 27, that is dispensed from a feeder (not shown) and with the itself by means of rollers 25 and 26 moving photosensitive member 2 is brought into contact and moves at the same speed how the moving photosensitive member 2 advances. To improve the image transmission quality a charge is developed at the image transfer point, the polarity of which is opposite to that of the developed Image forming toner is on the back of the egg pouch paper 27 applied.

This is done by a corona discharger 28. The toner image transferred onto the image receiving paper 27 is fixed by a suitable image fixing device such as a heat fixer. The image fixing device has a pair of pressure rollers 29 and 30 which are in pressure communication with the image tape. The paper is then transported to a collecting tray (not shown).

At the end of the image transfer process, the Surface of the photosensitive member 2 by means of an edge of a cleaning blade pressed against the surface 31 cleaned of residual toner so that for

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The following form the winding cycle again a clean one Surface is available. The aforementioned AC corona discharger 23 is mounted in this embodiment so that it discharges the charge on the surface of the "moving photosensitive member 2 is eliminated during the image exposure. However, it may equally well placed between the corona discharger 22 and the imaging system so that the elimination the charge of the surface dos moving photosensitive Member 2 takes place before the Bildbelichtting. In this case, the total exposure light bundle is 21 unnecessary. Further, the moving photosensitive member 2 may also have no surface insulating layer be executed. In this case, both the corona discharger 23 and the total exposure light bundle 21 are not mandatory. The pre-exposure light bundle 19 is used to charge before the primary for the first copy to irradiate the photosensitive layer to reduce its resistance with light, so that the resistance becomes the same size as the second copy sheet. The reason for this pre-exposure is that the Resistance of the material from which the photosensitive Layer exists, e.g. OdS, increases in the dark and increases when exposed to a certain, defined amount of light does not lower sufficiently so that the photosensitive Gchicht is difficult to discharge and the charge remains the same even for the white parts of the first copy sheet, after it has been left for a certain defined time (10 to 15 seconds) or longer, v / o by the

^ou entire picture becomes blackish. The blank exposure light bundle 20 serves the purpose described below. Even when an image for forming a latent image is not projected, the developing device 24 is operated by the movement of the photosensitive member. Because of this, if an adequate amount of light for illumination is not projected onto the moving photosensitive member 2 in the image exposure area, etc., there would arise a situation that the developing

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ler on the entire surface of the "moving light-sensitive member in compact black adheres. Since the developer is not transferred, it must be completely removed by the cleaning device. This increases the load on the cleaning device, which not only results in satisfactory cleaning is made more difficult, but also shortens the life of the cleaning device and the amount of the developer scattered in the reproduction apparatus increases rapidly, thereby causing malfunctions in the apparatus caused. In addition, the density of the developer in the developing device is decreased 24 abruptly with the increase in the amount of the developer supplied from the developing device 24 and a device for returning the developer from the cleaning device to the developing device must inevitably have large dimensions. To overcome these inadequacies, if the photosensitive member operates without image projection is, for a reasonable time, substantially uniform light is incident on the photosensitive member applied at a position at least before the developing section and, for example, at the image exposure section lies. The blank exposure light bundle 20 is only then incident on the moving photosensitive member 2 applied when no image exposure takes place.

In the explanations of the first embodiment it was mentioned that the lower deflecting mirror 5 consists of a plurality of. Mirroring with a flat surface exists so that the original support surface 6 can be illuminated in an area which is larger than the slot width 8, and that the second focal point of the enveloping ellipse passing through the center points of the mirror with a flat surface is at point A on the original Support surface 6 is. However, it is also permissible that the second focal point of the enveloping ellipse lies in front of or behind point A in the light path,

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in both of them fill that of the lower deflecting mirror 5 outgoing light bundles the original surface in one Area that is larger than the width of the slot is illuminated over a wide area.

In the description of the first and second exemplary embodiments, it was also mentioned that the second focal point of the upper deflecting mirror 9 lies in the vicinity of the upper part of the lens 1. Here, too, the second focal point can lie in the plane of the third deflecting mirror 11 or behind it. Although the width of the light beam above the lens 1 increases, the original surface can even be illuminated with the divergent light beam in a structure in which the upper deflecting mirror 9 is composed of a large number of mirrors with a flat surface in the same way as the lower deflecting mirror 5 , wherein the Ilüllflache, which goes through a point on the mirrors with a flat surface, forms a cylindrical surface with an elliptical cross-section, the first focal point of which is at the location of the light source. In this pail, the second focal point of the enveloping ellipse can lie either in front of, on top of or behind the third deflecting mirror in the light path. Furthermore, the upper deflecting a light DiffusionsbeLandlu <"■ - 'the irish to converge its characteristic light <o Itux remains It is also possible that instead of Hitzesehutz- or Wellenlöngenauswählfilter 15" or in connection with,!... A nitzeschutz- or wavelength selection layer is vapor-deposited onto this deflecting mirror.

The invention provides a slot lighting device created with compact dimensions, with which an effective illumination of originals with a certain thickness, e.g. books, bound documents itsv /., is achieved, even if the down directed surface to be illuminated is

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1 lie on one. The feed table lifts off easily wherever she is involved. Y / it will continue with the slot lighting device a uniform lighting of the slot area independent of light localities

5 displacements of the light source reached, the original with divergent rays obliquely from below essentially is symmetrically illuminated over a wide area.

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Claims (17)

Ίβϊ α { patent attorneys: IEDTKE - tJüHÜNG - l \ lMNE Dipl.-lng. H. Tiedtke Gn Dipl.-Chem. G. Buehling RUPE - I ^J ELLMANN Dipl.-Ing. R chins Dipl.-Ing. R Group Dipl.-Ing. B. Pellmann 3 Q O § 6 5 3 Bavariaring 4, P.O. Box 20 2403 8000 Munich 2 Tel .: 089-53 9653 Telex: 5-24 845 tipat cable: Germaniapatent Munich 06. "i" rz DE 0259 Claims (1., slot lighting device, characterized in that that an upper deflecting mirror (9) and a lower deflecting mirror (5; 5 ') are arranged in such a way that they form a light source (4) that one from the lower deflecting mirror (5; 5 ') reflected light beam and one from the upper deflecting mirror (9) and further by a third deflecting mirror (11) reflected light bundle a slot over a wide area and illuminate divergently, the third deflecting mirror (11) being located opposite the position of the light source (4) Page is located and with a path of light extending between them, which extends from the slot to an image forming Element (1) leads. 2. Schlitzbeluchtevoirrichtung according to claim 1, characterized in that the lower deflecting mirror (5; 5 ^! ) Consists of a plurality of flat mirrors and dai? the envelope surface, which passes through predetermined points on the plane mirrors, forms a cylindrical surface with an elliptical cross-section, the first focal point of which is in the vicinity of the center of the light source (4). 3. slot lighting device according to claim 2, characterized in that the second focal point is through the HulifTfläche formed cylindrical surface with elliptical Cross-section near the center of the slot in the Deutsche Bank iMunchenj Kto 51/61 OiO Dresdner Bank (Muncheni Klo. 3 · .ιί9Β · Ι4 Postscheck (Münchoni Kto 670-4: 3-801 030037/0842 -2- DE 0259 Light path lies. 4. slot illumination device according to claim 2, characterized in that the second focal point by the enveloping surface formed cylindrical surface with an elliptical cross-section lies in front of the slot in the light path. 5. slot lighting device according to claim 2, characterized in that the second focal point by the envelope surface formed by a cylindrical surface with an elliptical cross-section behind the slot in the light path lies. 6. slot lighting device according to claim 1, characterized in that the lower deflecting mirror (5; 5 ') part of a mirror with a cylindrical surface and elliptical cross-section, the first focus of which is near the center of the light source (4) and whose second focal point is in front of the slit in the light path. 7 · slot lighting device according to one of claims 1 to 6, characterized in that the upper Deflecting mirror (9) a part of a mirror with cylindrical Surface and elliptical cross-section, the first focus of which is near the center the light source (4) is located. 8. slot lighting device according to claim 7 »characterized in that the second focal point of the upper deflection mirror (9) in front of the third deflection mirror (11) in the light path. 9. slot lighting device according to claim 7, characterized in that the second focal point of the upper deflection mirror (9) lies on the third deflection mirror (11) in the light path. 030037/0842 -3- DE 0259 ] 10. Sohlitsbeluminationvorrichtunc according to claim 7, characterized in that the second focal point of the upper deflecting mirror (9) is behind the third deflecting mirror (11) in the light path.
5 11. slot lighting device according to claim 1, characterized in that the third deflecting mirror (11) is a mirror with a cylindrical surface. 12. slot lighting device according to claim 1, characterized in that the third deflecting mirror (11) is a mirror with a flat surface. 13. Slot lighting device according to claim 1, characterized in that the light source (4) is a linear light source is. 14. Slot illumination device according to claim 1, characterized in that the light source (4) has a is frosted light source, the bulb surface of which is a light-diffusing surface. 15. Slot lighting device according to claim 1, characterized in that in the light ^ d? <- the light source (4) a heat protection ' ⁰ IIt igenselection filter (15) in a Aussparungsberex ^ In aera upper deflecting mirror (9) and in the lower deflecting mirror ( 5; 5 ') is provided. 16. Slot lighting device according to claim 1, characterized in that a heat protection or Wavelength selection filter (15) by vapor deposition on the Deflection mirror is applied. 17. Ochlitzbelumination device according to claim 1, characterized in that the deflecting mirror one subject to slight diffusion treatment, v / obei their property of converging light is preserved. 030037/08/4? BATH ORIGINAL