JPH0131608B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an electrophotographic method, and particularly to an electrophotographic method for forming a potential image using a difference in distributed voltage caused by a change in resistance of a photoconductive layer. Conventionally, various electrophotographic methods are known. The most common electrophotographic process involves charging and imagewise exposure to form an electrostatic image. An electrostatic image is generally formed by charging the surface of a photoreceptor by corona discharge, and then selectively dissipating the charges in the exposed areas by imagewise exposure.
This electrostatic image is developed with toner charged with a polarity opposite to that of the electrostatic image, and is transferred onto transfer paper. It has been pointed out that this type of electrophotographic process requires wires and shield cases to perform corona charging, as well as high voltage to generate corona discharge, making it difficult to make the equipment more compact. . On the other hand, an electrophotographic method has been proposed which allows the apparatus to be easily made compact. Representative examples include JP-A No. 48-68238 and JP-A-Sho.
It is disclosed in JP-A-51-150342, JP-A-53-1027, JP-A-54-61534, and JP-A-54-61537. These methods can form potential images that can be developed with charged toner without requiring corona charging. That is, by applying a voltage to a photoconductive layer provided with electrodes to perform image exposure, a difference in voltage distribution is created between the exposed area and the unexposed area with respect to the applied voltage, thereby increasing the potential. It forms an image. The photoconductive layer used in a photoreceptor that forms a potential image may be formed of the same material as the photoconductive layer forming material of a conventional photoreceptor, but the resolution of the image formed depends on the electrodes of the photoreceptor and the isolated conductor described below. Therefore, it is generally difficult to manufacture a photoreceptor having an area corresponding to the area of the image to be copied, and also having fine patterned electrodes and isolated conductors. Conventionally, in order to form a color image using an electrophotographic photoreceptor, the original color image is exposed at least three times, and the exposure is performed through color filters, generally red, green, and blue color filters. It is something to do. Further, every three exposures, a toner image is formed according to an electrophotographic method using toner having a complementary color to the color of the color filter. For example, a photoreceptor is charged, imagewise exposed through a red filter, developed with cyan toner, and transferred to transfer paper. Next, a color image is formed by carrying out exactly the same process by replacing the color filter with a green filter and a blue filter, and replacing the developer with a magenta toner and a yellow toner. In such a conventional color image forming method using electrophotography, it is necessary to repeat image formation completely independently at least three times. For this reason, there are disadvantages in that color shift tends to occur in the formed image, making it extremely difficult to form a clear image, and requiring a long time. Therefore, the present invention is free from such drawbacks, that is,
The main object of the present invention is to provide an electrophotographic method that can use a photoreceptor that does not require an area corresponding to the area of an image to be copied. Another object of the present invention is to provide a method for forming a color image that does not cause color shift and requires a short time. The electrophotographic method according to the present invention has a photoconductive layer on a transparent support having a transparent electrode and an opaque electrode in contact with the transparent support, and isolated conductors forming pixels are provided on the photoconductive layer. The transparent electrode and the opaque electrode are arranged so as to be located below the isolated conductor, and the transparent electrode and the opaque electrode are arranged in correspondence with each other. Image exposure is performed with a voltage applied between the transparent electrode and the isolated conductor, and the divided voltage between the isolated conductor and the opaque electrode. The developer is attached to the image receiving member by an electric field caused by a potential image formed by the potential change of the isolated conductor that occurs in response to the difference in the distributed voltage, and the image receiving member and the electrophotographic image are connected to each other. This is characterized by moving the optical image irradiated onto the photoreceptor relatively. In the present invention, since the image receiving member moves during image formation, the required area of the photoreceptor can be much smaller than the area of the image to be formed, and the manufacturing of the photoreceptor can be dramatically facilitated. A color image can be formed by one image exposure, and therefore a method for forming a color image without color shift can be provided. Next, the present invention will be specifically explained with reference to the drawings. FIG. 1 is a sectional view of one embodiment of the photoreceptor used in the present invention, and is composed of a transparent support 1, a transparent electrode 2, an opaque electrode 3, a photoconductive layer 4, and an isolated conductor 5. The cross-sectional shapes of the photoreceptor support 1, photoconductive layer 4, transparent electrode 2, and opaque electrode 3 are shown in FIG. Both electrodes are striped. As shown in FIG. 3, the surface of the photoreceptor on the side of the isolated conductors 5 is formed such that the isolated conductors are isolated from each other. The finer the transparent electrode 2, opaque electrode 3, and isolated conductor 5, the better the resolution of the image. However, as the size becomes finer, it becomes more difficult to manufacture large-area patterns. Furthermore, the isolated conductors 5 do not necessarily have to be the example shown in FIG. 3, and may be arranged in parallel in several rows within the range that is manufacturable. For example, as shown in FIGS. 4 and 5, a considerable number of counter electrodes of transparent electrodes and opaque electrodes and isolated conductors may be assembled.
FIG. 4 shows the cross-sectional shapes of the photoconductive layer 44, the transparent electrode 42, and the opaque electrode 43. l ₁ is approximately 300 mm, l ₂ is approximately 5 mm, l ₃ of the transparent electrode 42 is 10 μm, l ₄ of the opaque electrode 43 is 30 μm, and l ₅ and l ₆ on the isolated conductor 45 side of the photoreceptor shown in FIG. is 50 μm. The support plate for the photoreceptor is transparent and made of glass, resin, or the like. Transparent electrodes and opaque electrodes can be formed by various methods, but typical methods include vapor deposition and chemical etching using photoresist. In this method, a material for forming a transparent electrode, such as In ₂ O ₃ or SnO ₂ , is first vapor-deposited on the surface of the support, and then a striped masking pattern is formed using photoresist. Then, after selectively etching away the layer such as In ₂ O ₃ using a predetermined etching solution such as acid or alkali, the masking pattern of the photoresist can be removed to form a transparent electrode.
Further, an opaque electrode is also formed on the support in exactly the same manner. Examples of opaque electrode forming materials include Al,
Ag, Pb, Zn, Ni, Au, Cr, Mo, Ir, Nb,
Various metals such as Ta, U, Ti, and Pt are used. These metals are formed into layers by vapor deposition, electron beam deposition, sputtering deposition, and the like. As the photoresist, any conventionally commonly used materials can be used. For example, as commercially available products, product name: KPR (Kodak Photo Resist, manufactured by Kodatsu... developer: methylene chloride, trichlene, etc.), product name: KMER (Kodak Metal Etch), etc.
Resist, manufactured by Kodatsuku...Developer: xylene, trichlene, etc.), Product name: TPR (manufactured by Tokyo Ohka...Developer: xylene, Trichlene, etc.), Product name: Shippray AZ1300 (manufactured by Shippray...Developer: Alkaline aqueous solution), Product name :NTFR (Kodak Thin Film)
Resist, made by Kodatsuku...Developer: xylene, trichlene, etc.), Product name: FNRR (Fuji Pharmaceutical Co., Ltd....Developer: chlorocene), Product name: FPER (Fuji Photo)
Etching Resist, manufactured by Fuji Photo Film...Developer:
Triclean), trade name: TESH DOOL (manufactured by Okamoto Chemical Industries, developer: water), and trade name: Fujiresist No. 7 (manufactured by Fuji Pharmaceutical Co., Ltd., developer: water). To remove the mask after use, trichloride, methylene chloride, AZ Remover (trade name: Shippray), sulfuric acid, etc. are used.
The transparent electrode and the opaque electrode can also be formed by depositing an electrode forming material onto the support through a mask having comb-shaped openings, and then removing the mask. The thickness of the transparent electrode is usually 500
The thickness of the opaque electrode is usually about 500 Å to 2 μ. The photoconductive layer includes S, Se, PbO and S, Se, Te,
It is formed by vacuum deposition of an inorganic photoconductive material such as an alloy or intermetallic compound containing As, Sb, etc. In addition, when using the sputtering method, ZuO, CdS, CdSe,
A high melting point photoconductive material such as TiO ₂ can also be attached to the support to form the photoconductive layer. Furthermore, amorphous Si formed by glow discharge can also be used as a photoconductive layer. In addition, when forming a photoconductive layer by coating, polyvinylcarbazole, anthracene,
Organic photoconductive materials such as phthalocyanine, dye-sensitized or Lewis acid-sensitized materials, and mixtures of these with insulating binders are used. Also suitable are mixtures of inorganic photoconductors such as ZnO, CdS, TiO ₂ , PbO, etc. with insulating binders. Note that various resins are used as the insulating binder. The thickness of the photoconductive layer depends on the type and characteristics of the photoconductive material used, but is generally about 1 to 100 microns, particularly about 5 to 50 microns. An isolated conductor is a discontinuous island-like conductor, and is an important conductor that becomes a pixel of an image to be formed. Although the shape of the isolated conductor is square as shown in the plan view of FIG. 3, it may have another shape such as a circle. The formation of isolated conductors can be carried out in exactly the same way as for transparent or opaque electrodes. Next, FIG. 6 shows a typical process for forming an image using the photoreceptor shown in FIGS. 4 and 5. First, a paper image of an original 62 is formed on a photoreceptor 61 by a lens 66;
There is a mesh screen 64 containing developer between an image receiving member 65 such as a film and the photoreceptor 61, and new developer is always supplied by a developer replenishing section 63. A developing electrode 67 is installed on the opposite side of the screen 64. A voltage is applied between the transparent electrode 68 and the opaque electrode 69.
Va is being applied, and a voltage Vb is also applied to the developing electrode 67. Vb is the type of developer and isolated conductor 6
10 potentials are selected as appropriate while checking the image condition. The image receiving member 65 moves in the direction of arrow 612 and the original 62 moves in the direction of arrow 611. Of course, as in a general electrophotographic copying machine, the original may be fixed and the optical system for irradiating the photoreceptor with an optical image may be moved to move the optical image irradiated onto the photoreceptor. By moving the original 62 and the image receiving member 65 in opposite directions at the same speed as shown in the figure, the image of the original 62 is projected onto the image receiving member 65. That is, the equivalent circuit of the photoreceptor at this time is expressed as shown in FIG. R ₁ is the resistance between the opaque electrode 69 and the isolated conductor 610, and R ₂ is the resistance between the isolated conductor 610 and the transparent electrode 68. isolated conductor 610
The potential Vo at is between the transparent electrode 68 and the isolated conductor 6
9, and is expressed by Vo=R ₁ /R ₁ +R ₂ Va...Equation (1). By performing image exposure from the color filter side with voltage Va applied, a difference is created in the potential of the isolated conductor between areas where light passes through the transparent electrode and areas where light does not pass through the transparent electrode. Regarding the transparent part, since exposure light does not reach the photoconductive layer in the part shielded by the opaque electrode, the resistance R ₁ between the opaque electrode and the isolated conductor remains unchanged.
In addition, since the exposure light reaches the photoconductive layer in the transparent electrode part, the resistance between the isolated conductor and the transparent electrode increases.
If the formula (1) in which R ₂ decreases is transformed into Vo=1/R ₂ /R ₁ +1Va . . . formula (2), it will be directly shown that if the resistance R ₂ decreases, the potential of the isolated conductor will increase. On the other hand, in the non-transparent part, neither R ₁ nor R ₂ changes, so the potential of the isolated conductor does not change. Therefore, the potential is high in the transparent part and low in the non-transparent part, forming a potential image. For example, if R ₂ decreases by three orders of magnitude or more in the transmission part, R ₂ /R ₁ ≈0 and Vo≈Va. At this time, R ₁ ≒ R ₂ in the non-transparent part, but Vo
≒1/2Va. Next, FIG. 8 shows a mode of forming a color image, which is one of the objects of the present invention. Basically, it is the same as the case shown in FIG. 6, but by installing three sets of photoreceptors, a color image is produced by one image exposure. 805 is an opaque electrode, 806 is a transparent electrode, and 807 is a photoconductive layer. Photoreceptor support 80
Color filters 801, 802, 80 on top of 4
3 is provided, and the rest is basically the same as in FIG. The color filters 801, 802, and 803 can be formed on the support 804 by a method similar to that used for manufacturing conventional color filters. For example, typical methods include a vapor deposition method and a dyeing method. The vapor deposition method manufactures color filters using interference filters, in which multiple layers of thin films with different refractive indexes are vapor-deposited to a predetermined thickness on a support, and the desired wavelength range ( A color filter of red, green, and blue is formed in such a way that only the colors (red, green, and blue) are allowed to pass through. In the dyeing method, a resin such as polyvinyl alcohol, gelatin, polyurethane, or polycarbonate is coated on a support to form a dye-receiving layer, and a dye is applied to this to form a filter. (1) Suitable sublimable red dyes include Seriton Scarlet B (manufactured by Vadateshiyu), Diaceriton Fast Pink R (manufactured by Mitsubishi Kasei), Tyrasil Brilliant Pink 4BN (manufactured by Ciba Gaiki), and Kayalon. Red R (manufactured by Nippon Kayaku), Sumikaron Red E-FBL (manufactured by Sumitomo Chemical), Resolin Red FB (manufactured by Bayer AG), Sumiacryl Rhodamine 6GCP (manufactured by Sumitomo Chemical), Eisen Cachilon Pink FGH (manufactured by Hodogaya Chemical), Makiron Brilliant Examples include Red 4G (manufactured by Ciba Gaiki) and Diacryl Splat Brilliant Pink RN (manufactured by Mitsubishi Kasei). Red dyes suitable for application include Suminol Fast Red Bconc (manufactured by Sumitomo Chemical) and Eisen Brilliant Scarlet.
3RH (Hodogaya Chemical), Azorbinol 3GS250
% (manufactured by Mitsubishi Kasei), Kayaku Acid Rhodamine FB (manufactured by Nippon Kayaku), Acid Anthracene Red 3B (manufactured by Chugai Kasei), Benzyl Fast Red B (manufactured by Ciba Geigy), Palatin
Examples include Fast Stretched RN (manufactured by Vadice), Nyromine Red 2BS (manufactured by ICI), Ranaf Strand 2GL (manufactured by Mitsui Toatsu Chemicals), and Rose Bengal (manufactured by Kenji Kasei). (2) Suitable sublimable green dyes include Eisen Diamond Green GH (manufactured by Hodogaya Chemical), Eisen Malachite Green (manufactured by Hodogaya Chemical), Brilliant Green (manufactured by Dupont), First Green JJO (manufactured by Ciba Geigy), and Cinnamon. Krill Green (manufactured by ICI),
Examples include Victoria Green (manufactured by Dupont). Green dyes suitable for coating include Kayakaran Blue Black 3BL (manufactured by Nippon Kayaku);
Sumilan Green BL (manufactured by Sumitomo Chemical), Eisen Froselan Olive Green GLH (manufactured by Hodogaya Chemical), Diacid Cyanine Green
GWA (manufactured by Mitsubishi Kasei), Chibaran Green GL
(manufactured by Ciba Geigy), Carboran Brilliant Green 5G (manufactured by ICI), Palatin Fast Green BLN (manufactured by Vadeitshu), Acid Green GBH (manufactured by Takaoka Chemical), Acid Brilliant Milling Green B
(manufactured by Mitsui Toatsu Chemical Co., Ltd.). Green color can also be produced by combining a blue dye and a yellow dye. (3) Suitable sublimation blue dyes include Miketon First Blue Extra (manufactured by Mitsui Toatsu Chemical Co., Ltd.), Kayalon First Blue FN (manufactured by Nippon Kayaku Co., Ltd.), Sumikalon Blue E-BR (manufactured by Sumitomo Chemical Co., Ltd.), and Thyrasil Blue. 2R (manufactured by Ciba Geigy), Varanil Blue R (manufactured by Vadeitshu),
Eisen Brilliant Basic Cyanine
6GH (manufactured by Hodogaya Chemical), crampons carotene blue GLH (manufactured by Hodogaya Chemical), Chiba Set Blue
F3R (manufactured by Ciba Geigy), Diaceritone First Brilliant Blue B (manufactured by Mitsubishi Kasei), Desbasol Blue BN (manufactured by ICI), Resolin Blue FBL (manufactured by Bayer AG), Latile Blue FRN (manufactured by Dupont), Ceblon Blue ER (manufactured by Dupont) , Diacrylic Brilliant Blue H2R-N (manufactured by Mitsubishi Kasei). Blue dyes suitable for coating include Orient Soluble Blue OBC (manufactured by Orient Chemical Co., Ltd.) and Suminol Revering Blue.
4GL (manufactured by Sumitomo Chemical), Kayanol Blue N2G
(manufactured by Nippon Kayaku), Mitsui Alizarin Saphyrol B (manufactured by Mitsui Toatsu Chemical), Xylene First Blue BL200% (manufactured by Mitsubishi Kasei), Alizarin First Blue R (manufactured by Ciba Geigy),
Carboran Brilliant Blue 2R (manufactured by ICI), Palatin First Blue GGN
(manufactured by Vadateshiyu), Eisen Opal Blue New Conc (manufactured by Hodogaya Chemical), Fastogen Blue SBL (manufactured by Dainippon Ink Chemical), etc. In addition to being formed on the support as shown in FIG. 8, the color filter may be formed directly on the photoconductive layer, the transparent electrode, and the opaque electrode surface. Further, the color filter does not need to be formed on the entire surface of the photoreceptor, and may be formed selectively above the transparent electrode. The relationship between the potentials of the isolated conductors 808 corresponding to the red filter 801, the green filter 802, and the blue filter 803, which are generated corresponding to each color portion of a color image original, is shown in the following table. Note that the toner of the developer adhered to the image receiving member by the photoreceptor equipped with a red filter is cyan,
A magenta toner is used for a photoreceptor equipped with a green filter, and a yellow toner is used for a photoreceptor equipped with a blue filter.

【table】

[Table] Toner adhesion to the image receiving member of a photoconductor equipped with a red filter is such that no electric field is generated between the isolated conductor and the conductive substrate in the white and red areas of the document, but in other colored areas. In this case, an electric field is formed between the isolated conductor and the conductive substrate. Therefore, if cyan toner having the same polarity as Va is supplied, the toner will remain on the screen mesh in the white and red areas, but will move to the image receiving member in other color areas. The toner transferred to the image receiving member is heated by the heater to the melting point of the toner, so that the toner image is fixed. Following this step, the image receiving member is moved to the photoreceptor of the green filter and the blue filter, and is developed and fixed with magenta and yellow toners of the same polarity, respectively, thereby forming a color image according to the table above. . To prevent fogging and the like, a voltage having the same polarity as Va and slightly lower than Va (greater than 1/2 Va) may be applied to the developing electrode 814 instead of the ground. Depending on the specific difference in the structure of the transparent electrode and the opaque electrode, the magnitude of the applied voltage, or the characteristics of the photoconductive layer, the potential of the isolated conductor can be changed as appropriate within a permissible range around 1/2 Va or Va. It is something that comes. Regarding polarity, by grounding the transparent electrode side, a potential completely opposite to that shown in the table above can be generated in the isolated conductor. In this case as well, a color image can be formed in the same way by changing the polarity of the toner used. Furthermore, in order to clearly reproduce the image quality of a color image, especially the black part, it is also effective to use a photoreceptor not equipped with a color filter, and to apply black toner to the image receiving member using the photoreceptor. Further, as another embodiment of the present invention, the color filter may be separated from the photoreceptor and run simultaneously with the color filter and the photoreceptor. In this case, one photoreceptor may be run repeatedly, for example, three times, and Color images can also be formed by replacing the color filter each time. The above is about the method of forming a color image, but in the case of forming a general black image, a photoreceptor that does not require a color filter is used, and the image is developed by running the photoreceptor within the image exposure area. It is capable of forming images. One photoreceptor is sufficient for forming such an image that is not a color image. In the present invention, transparent and opaque mean transparent to light used for image exposure and opaque, and are not limited to visually transparent or opaque.

[Brief explanation of drawings]

FIG. 1 shows one embodiment of the electrophotographic photoreceptor used in the present invention. FIG. 2 is a sectional view of the electrophotographic photoreceptor shown in FIG. 1. FIG. 3 is a surface view of the electrophotographic photoreceptor shown in FIG. 1. FIG. 4 shows another embodiment of the electrophotographic photoreceptor used in the present invention. FIG. 5 is a surface view of the electrophotographic photoreceptor shown in FIG. 4. 6th
The figure shows one embodiment of the electrophotographic method according to the invention. FIG. 7 shows an equivalent circuit of the electrophotographic photoreceptor shown in FIG. FIG. 8 shows another electrophotographic method according to the present invention.
Indicates the mode. DESCRIPTION OF SYMBOLS 1... Support, 2... Transparent electrode, 3... Opaque electrode, 4... Photoconductive layer, 5... Isolated conductor, 62
...Original document, 63...Developer supply unit, 64...Mesh screen, 65...Image receiving member, 66...Lens, 67...Developing electrode, 68...Transparent electrode, 6
9... Opaque electrode, 610... Isolated conductor.

Claims (1)

[Scope of Claims] 1. A photoconductive layer having a transparent electrode and an opaque electrode in contact with the transparent support on a transparent support, and isolated conductors forming pixels are provided on the photoconductive layer. The transparent electrode and the opaque electrode are arranged so as to be located below the isolated conductor, and the transparent electrode and the opaque electrode are arranged opposite to each other. Image exposure is performed with a voltage applied between the transparent electrode and the isolated conductor, and between the isolated conductor and the opaque electrode. While the developer is attached to the image receiving member by an electric field caused by a potential image formed by a potential change of the isolated conductor that occurs in response to the difference in divided voltage,
An electrophotographic method characterized by relatively moving an image receiving member and an optical image irradiated onto an electrophotographic photoreceptor. 2. A photoconductive layer having a transparent electrode and an opaque electrode in contact with the transparent support is provided on the transparent support, an isolated conductor forming a pixel is provided on the photoconductive layer, and the transparent electrode and the opaque electrode are provided on the photoconductive layer. The electrode is arranged to be located below the isolated conductor, and the transparent electrode and the opaque electrode are arranged to face each other. A voltage is applied between the transparent electrode and the opaque electrode of the electrophotographic photoreceptor. Image exposure is performed through a color filter in the state of The color developer corresponding to the color light transmitted through the transparent electrode by the electric field caused by the potential image formed by the potential change of the isolated conductor that occurs in response to the difference in the distributed voltage is applied to the image receiving member. An electrophotographic method characterized by relatively moving an image receiving member and an optical image irradiated onto an electrophotographic photoreceptor while adhering to the image receiving member. 3. The electrophotographic method according to claim 2, wherein three types of filters, a red filter, a green filter, and a blue filter, are used as color filters. 4. The electrophotographic method according to claim 2, wherein the color filter is integrated with the electrophotographic photoreceptor.