WO1991004518A1 - Printing press using charge retaining medium, its manufacturing method and stripping system using charge retaining medium - Google Patents

Abstract

A photoconductive layer (5) of a photosensitive member (1) and a charge retaining layer (6) of a charge retain medium (2) are so disposed as to face each other with a predetermined distance (d). After a power source (8) is connected, light (9) having a predetermined wavelength is irradiated to the photosensitive member (1) to form an electrostatic latent image in the charge retaining layer (6) of the charge retaining medium (2). Next, the charge retaining medium (2) is disconnected from the power source (8), toner is applied onto the charge retaining layer (6) and development and fixing are carried out. Etching is then conducted using the resulting toner image (16) as a mask to remove the portions of the charge retaining layer (6) to which the toner (16) is not deposited. In this manner a printing plate having a scanned portion formed by the toner (16) and the charge retaining layer (6) on the conductive substrate (7) can be obtained. According to this plate, the toner image is formed directly on the charge retaining layer (6) of the charge retaining medium (2). Therefore, the toner image need not be transferred and a scanned portion having high resolution can be formed.

Description

 Description Printing plate using charge retention medium, method for producing the same, and

 Plate collection system using charge retention media

 The present invention relates to a printing plate formed of a charge holding medium, a manufacturing method for manufacturing a printing plate with the charge holding medium, and a document directly printed at a predetermined magnification on a predetermined position on the printing plate formed of the charge holding medium. The present invention relates to a plate collection system using a charge holding medium that forms a plate by forming an electrostatic latent image of the image.

 Background technology

 Conventionally, as a printing plate manufacturing method, for example, a method as shown in FIG. 17, FIG. 18 or FIG. 19 is known.

The manufacturing method of the printing plate shown in FIG. 17 is roughly as follows. First, a photosensitive resin layer 101 is formed on a so-called grained aluminum plate 100 by a known polishing method such as ball polishing or brush polishing to form a printed substrate. A film 102 for forming a plate is placed opposite to the resin layer 101, pattern exposure is performed by ultraviolet rays 103 (FIG. 17 (a) :), development and drying are performed. Thus, a printing plate having an image portion formed of the resin layer 101 is manufactured as shown in FIG. 17 (b). The film 102 is called a layout scanner or a page make-up scanner. It goes without saying that the film is a page make-up film such as the one output from a color scanner. The same applies to the following. In the case of color printing, printing plates must be manufactured for each of the four colors: yellow (Y :), magenta (M :), cyan (C), and black (K). Naturally, by using the film for each of the above four colors as the film 102 in FIG. 17 (a), four color printing plates of Y, M, C, and K were manufactured. can do.

 In general, a photosensitive layer formed on a grained aluminum plate is called a PS plate (presensitized * plate) and is widely marketed. The PS plate is expensive, but the workability is good because the photosensitive layer has already been applied.

 In a printing shop having photosensitive layer coating equipment, the photosensitive layer is actually coated on an aluminum plate grained as described above. The plate produced in this way is called a wipe-on plate. The wipe-on plate can be manufactured at a lower price and can be manufactured with higher sensitivity than the PS plate, but the workability is inferior to the PS plate due to the necessity of a coating process. In addition, the wipe-on plate has a short shelf life from application to use, and it is necessary to start the exposure process immediately after forming the photosensitive layer, which also imposes operational restrictions.

Currently, the wipe-on version is rarely used, and the PS version is the mainstream. As described above, the PS plate has excellent workability, but the sensitivity of the photosensitive layer is not high because it must withstand long-term storage with the photosensitive layer applied. In general, the higher the sensitivity, the easier it is to react to heat, and the capri due to the thermal reaction is generated during storage. It is very difficult to increase the sensitivity of the PS version, since it will be more likely to be lost.

 FIG. 18 shows that a photosensitive resin layer 106 is formed on a grained aluminum plate 105 and a silver emulsion layer 107 is further formed thereon. A printing plate can be manufactured by subjecting the printed substrate to pattern exposure, development and drying in the same manner as shown in FIG. This was developed to capture the disadvantage of the low sensitivity of the PS plate described above.A silver emulsion layer was provided on the PS plate, and the primary exposure was performed with low energy using the high sensitivity of the silver emulsion. A silver particle pattern developed by developing a silver emulsion is used as an original to perform uniform exposure (secondary exposure) over the entire surface, and then developed to form a printing plate. The aim is to use it for low energy exposure such as laser scanning exposure and projection exposure.

 Exposure of the printing plate by laser scanning involves sending information over a communication line to a remote printing factory and printing, as seen in the production of printing plates in the U.S. newspaper, ゥ All Street Journal. This is a very important technology. Also, with projection exposure, a plate can be produced as soon as a reflective original is made, eliminating the need for a conventional film-making machine to make film originals.

These have great advantages in that they enable low-energy exposure, but they are naturally more expensive than PS plates due to the lamination of expensive silver emulsions. It is. The printing plate manufacturing method shown in FIG. 19 is a method using electrophotography. First, a uniform electrostatic charge is applied to a photoreceptor 110 made of a photoconductive material by corona charging to form a film 111. Are arranged and exposed to a pattern with light 112 having a predetermined wavelength (FIG. 19 (a) :), and toner 113 is applied (FIG. 19 (b)). As a result, the toner 113 adheres only to the unexposed portion of the light 112. After that, the toner 113 is transferred to a grained aluminum plate 1U and fixed, whereby a printing plate having the toner 113 as an image portion can be obtained. (Fig. 19 (c) :).

 The printing plate manufacturing method shown in FIG. 20 is another method using electrophotography. First, a photoconductor 123 composed of a photoconductive material layer 122 and a grained aluminum plate 121 is used. A uniform electrostatic charge is given by corona charging, a film 124 is arranged, and pattern exposure is performed by light 125 having a predetermined wavelength (FIG. 20 (a)), and toner 12B is applied. As a result, the toner 126 adheres only to the unexposed portion of the light 125. After that, the toner 12B is fixed (FIG. 6 (b) :), and the exposed portion of the photoconductive material layer 122 is eluted with the toner 126 as a resist, and the grained aluminum of the substrate is eluted. Expose the rubber plate 121 (FIG. 6 (c)). In this way, it is possible to obtain a printing plate in which the remaining photoconductive material layer 122 and the toner 126 are used as an image area and the exposed portion of the grained aluminum plate 121 is used as a non-image area. it can.

As described above, various methods are known as a printing plate manufacturing method. However, the conventional manufacturing method has the following problems. That is, the product shown in FIG. In the fabrication method, a resin with high sensitivity is required for exposure to ultraviolet light, but a material that is highly sensitive to ultraviolet light generally has poor thermal stability and is susceptible to so-called heat cover. In addition, since a high-sensitivity resin has a relatively small molecular weight, there is a problem that the printing durability, that is, the mechanical strength required for a printing plate is low. Very difficult.

 On the other hand, in the printed circuit board shown in Fig. 18, the sensitivity can be increased by using a silver emulsion, and the resin layer 106 that is conventionally used is used. Yes, but it is expensive.

 In the method shown in FIG. 19, the relative speed at which the toner image formed on the photoreceptor 105 is transferred to the aluminum plate 1U must be zero, and the relative speed must be zero. If it is not zero, the printing will be misaligned or the pattern will be distorted, which is particularly noticeable in the case of large-area printing plates. In addition, the toner may be disintegrated during the transfer, which causes deterioration in resolution.

 The method shown in FIG. 20 has an advantage over the method shown in FIG. 19 in that the toner image is not disturbed at the time of toner transfer in that toner transfer is not performed. However, since the photoconductive material layer is used as an image portion, it is necessary that the photoconductive material layer has both sensitivity and mechanical strength.

Generally, the photoconductive material layer is formed by dispersing a photoconductive pigment such as zinc oxide in a polymer material. -B- To obtain sufficient sensitivity, it is necessary to add about 80% by weight of zinc oxide. As a result, the photoconductive material layer is brittle and printing durability cannot be obtained.

 Further, in order to solve such problems, the exposed surface of the photoconductive material layer 122 is exposed to phosphoric acid or the like while the toner is fixed on the photosensitive plate 123 as shown in FIG. 20 (b). A printing plate in which the toner portion is used as an image portion and the exposed portion of the hydrophilic photoconductive material layer is used as a non-image portion without performing elution of the photoconductive material layer by performing a hydrophilic treatment. A way to get it was also suggested. However, in this method, the hydrophilicity of the photoconductive surface is not limited to the lipophilicity of the photoconductive pigment such as zinc oxide, and the polymer material as the binder is lipophilic. There is a drawback that accidents such as background contamination are likely to occur, and once ink has adhered to the non-image area, it cannot be re-hydrophilized, so that the plate itself must be replaced.

 As described above, according to the electrophotographic method that has been performed so far, when the photoconductive material layer is used as an image portion, the photoconductive property and the mechanical strength characteristic required for the image portion cannot be compatible. Conversely, when the photoconductive material layer is used as a non-image portion, the hydrophilicity required for the non-image portion is not sufficient. Therefore, if the toner is transferred to another grained aluminum or the like without fixing the toner on the photoconductor, the toner image is disturbed and the resolution cannot be maintained.

The conventional printing plate, printing plate manufacturing method and their We have explained the issues, but the following is a description of the conventional plate collection system.

 Conventionally, when performing plate collection, if the number of originals is small, attach the originals to the input drum of the point-by-point color scanner, set the disassembly conditions, and set C, at the specified magnification. Color separation into four colors of Μ, ,, and Κ is performed and electronically collected by a plate collecting device.If the number of originals is large, multiple scannings of different magnifications can be separated by one scanning. So that you can

 Intermediate duplication ratio-(final magnification) / (scanning magnification) The duplication of a blank original is performed at the intermediate duplication ratio determined by the relationship. In this way, by making a copy of the color original as an intermediate process, the scanning magnification is unified. Therefore, originals with different final magnifications are stuck on the same scanning drum using this intermediate copy color, and color separation work is proceeding efficiently.

 In addition, some intermediate duplicate manuscripts are pasted in consideration of the final layout to streamline the plate collection process.

These working techniques are called dupe assembly. However, in the former method, the resolution of the color scanner must be set for each point of the document, and the input magnification and color separation conditions must be set. The setting of the conditions depends on the experience of the operator, and requires a lot of skill. In the end, it was impossible to improve the operation rate of expensive color scanners. Furthermore, in order to collect a large amount of data input and created for each manuscript in accordance with the layout instructions, arithmetic processing on a computer is required, and the processing time becomes longer. As a result, not only the color scanner, but also the operation rate of the computer for printing will be reduced.

 In addition, when performing the latter duplication assembly, the disassembly conditions of the color scanner need only be set once, but there is a problem that it takes a very long time and cost to make a duplicate.

 In addition, it is difficult to avoid image degradation such as high image quality by making duplicates.Since a single scan is performed, multiple originals are separated under the same setup conditions. This means that color separation cannot always be performed under the optimal setup conditions for each original document, and for the same reason, this work method cannot be used for documents whose setup conditions differ greatly. And other problems.

The present invention has been made in view of such circumstances, and an object of the present invention is to form a toner image directly on a charge holding medium, thereby eliminating the need for transfer and improving printing durability. It is an object of the present invention to provide a printing plate and a method for manufacturing the same, and to improve the work efficiency of the plate collection by directly collecting a plate on a charge holding medium by a voltage application exposure method. It is intended to provide a plate collection system using a charge holding medium that can be used. Disclosure of the invention

 In order to achieve the above object, a printing plate using the charge holding medium of the present invention is characterized by having an image portion formed of a charge holding layer and a toner layer on a conductive substrate.

 The printing plate using the charge holding medium of the present invention has the following effects because it has an image area formed of a charge holding layer and a toner layer on a conductive substrate.

 In other words, the charge holding layer material itself does not need to have photosensitivity or photoconductivity, and only has to hold charge for a short period of time until development, so that printing durability and resolution can be selected from a wide range of materials. It is possible to select materials with excellent properties, and it is easy to select materials. In addition, materials that do not have photosensitivity or photoconductivity generally have high mechanical strength, and therefore have good printing durability.

 In the non-image area, the base metal material of general lithographic printing plates with excellent hydrophilicity can be used, so that sufficient water retention is obtained and the dampening solution can be easily controlled during printing. Workability is good.

 In addition, since the image area is covered with the toner layer, it has sufficient lipophilicity, has good print-out inking property, and provides high-quality printed matter immediately after printing is started. Furthermore, even if a part of the toner is worn due to continuous printing, since the charge retaining layer is provided under the toner layer, high printing durability can be obtained without causing a chipped image area or the like.

Further, a method of manufacturing a printing plate using the charge holding medium of the present invention comprises: a charge holding medium comprising a conductive substrate and a charge holding layer; A first step of forming a static latent image having a predetermined pattern on the charge holding layer by applying a predetermined voltage between the photoreceptor and exposing a predetermined pattern from the photoreceptor side; A second step of developing and fixing the electrostatic latent image on the charge holding layer obtained in the first step with toner, and a charge holding of a portion other than the toner image obtained in the second step And a third step of removing the layer.

 According to such a manufacturing method, the toner image is formed directly on the charge holding layer of the charge holding medium by the voltage application exposure method, so that it is not necessary to transfer the toner image as in the conventional manufacturing method, and therefore, the resolution is low. It is possible to form a high image area.

 In addition, the photosensitivity at the time of exposure can be borne by the photoreceptor, and the printing ability can be borne by the charge holding layer, so that the photosensitive function and the printing durability function can be separated. However, the range of choice of materials to be used is expanded.

 The voltage application exposure method has high sensitivity, and it is possible to give the spectral sensitivity to the wavelength of the laser light by selecting the type of photoreceptor, so that low-energy exposure becomes possible. A scanning exposure method using the light can be adopted. For the same reason, there is an advantage that an inexpensive light source such as a tungsten lamp can be used.

 Furthermore, since projection exposure is also possible, a small-sized original can be enlarged and projected, and the storage space of the original can be reduced.

Further, in the plate collection system using the charge holding medium of the present invention, the photoreceptor and the charge holding medium are arranged to face each other, and By exposing an image of a printed document to a predetermined position at a predetermined magnification and direction from the photoreceptor side while applying a predetermined voltage between the photoreceptor and the charge holding medium, It is characterized in that an electrostatic latent image of the image of the printed document is formed, and the charge of the electrostatic latent image is read by a reading sensor.

 According to such a plate collection system, an image of a document is directly exposed to a photoreceptor at a specified position at a specified magnification, and a latent image formed on a charge holding medium is read. All trimming and other processing can be performed electrically. Therefore, unlike the conventional plate collection work, it is not necessary to set the color separation conditions of the color scanner for each manuscript, and it is not necessary to perform the dupe assembly. Furthermore, the plate collecting work can be easily performed, and the operation rates of the color scanner and the computer can be improved. As a result, the printing plate making process can be efficiently performed. .

 BRIEF DESCRIPTION OF THE FIGURES

 FIG. 1 is a cross-sectional view showing one embodiment of a method of manufacturing a printing plate using a charge holding medium according to the present invention,

 FIG. 2 is a cross-sectional view showing one configuration example of the conductive substrate,

 FIG. 3 is a cross-sectional view for explaining an image recording method using a charge holding medium,

 FIG. 4 is a cross-sectional view for explaining a color image recording method using a charge holding medium,

Figure 5 shows the reading of an electrostatic latent image recorded on a charge storage medium. Diagram for explaining the method,

 FIG. 6 is a diagram showing a configuration of a color separation optical system,

 FIG. 7 is a diagram for explaining the formation of a color electrostatic latent image, FIG. 8 is a diagram showing an example of a fine color filter,

 Figure 9 shows an example of combining a fine color filter and a Fresnel lens.

 Fig. 10 is a diagram showing the three-plane division by the combined use of the ND filter and the R, G, and B filters.

 FIG. 11 is a diagram for explaining the exposure of a document image in a plate collection system using a charge holding medium,

 FIG. 12 is a diagram showing an example in which the electrostatic latent images of R, G, and Β are formed on separate charge holding media.

 FIG. 13 is a diagram showing an example in which the R, G, and B electrostatic latent images are formed on one charge holding medium.

 FIG. 14 is a diagram showing an example of an image data processing process, FIG. 15 is a diagram for explaining halftone dot processing,

 FIG. 16 is a diagram for explaining a halftone dot forming method,

 FIG. 17 is a sectional view showing a first example of a conventional printing plate manufacturing method,

 FIG. 18 is a cross-sectional view showing a second example of a conventional printing plate manufacturing method.

 FIG. 19 is a sectional view showing a third example of a conventional printing plate manufacturing method.

FIG. 20 is a sectional view showing a fourth example of the conventional printing plate manufacturing method. BEST MODE FOR CARRYING OUT THE INVENTION

 First, a printing plate using a charge holding medium and a method for manufacturing the printing plate will be described.

 In FIG. 1, 1 is a photoreceptor, 2 is a charge holding medium, 3 is a photoreceptor support, 4 is a photoreceptor electrode, 5 is a photoconductive layer, 6 is a charge holding layer, 7 is a conductive substrate, and 8 is a power supply. Is shown.

The method of manufacturing a printing plate using the charge holding medium according to the present invention utilizes an image recording method by a voltage application exposure method. First, an electrostatic latent image is formed on the charge holding layer 6 by a voltage application exposure method. An image is formed. Specifically, it is as follows. As shown in FIG. 1 (a), a photoconductive layer 5 of a photoconductor 1 formed by forming a photoconductor electrode 4 and a photoconductive layer 5 on a photoconductor support 3 in this order, A charge holding layer 6 of a charge holding medium 2 formed by depositing a charge holding layer 6 on a substrate 7 is arranged facing a charge holding layer 6 at a predetermined distance d. Next, for example, FIG. ), The power supply 8 is connected so that the photoconductor electrode 4 is on the positive side and the conductive substrate 7 is on the negative side, and light 9 of a predetermined wavelength is irradiated from the photoconductor 1 side. Perform more exposure. In a dark place, there is no change between the electrodes because the photoconductive layer 5 is a high resistance material, but when light enters from the photoconductor 1 side, the photoconductive layer 5 in the portion where the light enters is The photocarriers exhibiting conductivity and generated inside are accumulated as image charges on the charge holding layer 6 by discharging. Thus, a desired electrostatic latent image can be formed on the charge holding layer 6 of the charge holding medium 2 as shown in FIG. 1 (b). In the exposure, as shown in FIG. 1 (c), a predetermined pattern was formed at an appropriate distance from the photoconductor support 3 or in close contact with the photoconductor support 3. The pattern exposure may be performed by disposing a film 10 and irradiating a predetermined light 11 onto the entire surface of the film, or as shown in FIG. Exposure may be performed by scanning in the direction indicated by arrow 13 with. Also, for example, in FIG. 1 (d), the laser light 12 is modulated by image data made up by a color scanner without using the film original 10, and the modulated laser It goes without saying that exposure can also be performed by irradiating light. In the case of so-called light printing in which printing is performed in a relatively small size, the photosensitive member 1 formed in the same size as the charge holding medium 2 is charged as shown in FIGS. 1 (b) to (d). Although it is possible to perform exposure while facing the holding medium 2, it is difficult to keep the distance between the photoconductor 1 and the charge holding medium 2 at a predetermined value d, such as when printing a large area. In some cases, for example, as shown in FIG. 1 (e), the photoconductor 1 is formed in a substantially semi-cylindrical shape, and scanning (main scanning) by the laser light source 17 is performed along a straight line indicated by U in the figure. The photosensitive member 1 is moved at a predetermined speed while maintaining a predetermined distance d in a direction indicated by an arrow 15 in the drawing or in a direction opposite to the direction, thereby performing sub-scanning. What is necessary is to do.

After forming an electrostatic latent image of a predetermined pattern on the charge holding layer 6 as described above, the charge holding medium 2 is disconnected from the power supply 8, The toner is applied to the charge holding layer 6 for development, and subsequently heated to fix the toner. Thereby, as shown in FIG. 1 (f), the electrostatic latent image formed on the charge holding layer 6 appears as a toner image 16. Next, using the toner 18 as a mask, etching is performed by an appropriate method to remove a portion of the charge holding layer 6 where the toner 16 is not attached. As a result, a printing plate having an image portion formed by the toner 16 and the charge retaining layer 6 on the conductive substrate 7 as shown in FIG. 1 (g) can be obtained.

 The above is one embodiment of a method of manufacturing a printing plate using a charge holding medium. Next, each of the above materials and manufacturing conditions will be described.

 Examples of the photoreceptor support 3 include transparent glass such as ordinary glass, quartz glass, non-alkali glass, and pyrex glass (trade name), acrylic, and polycarbonate. Light, such as transparent thermoplastic resin such as polystyrene, polystyrene, polystyrene, polyethylene, and polypropylene, and transparent thermosetting resin such as epoxy resin and polyimide resin. A transparent material that transmits active light to the conductive layer 5 can be used. The thickness should be in the range of 10〃m to 10ma, especially for glass and plates such as acrylic and polycarbonate. ~ LOmm should be fine. When films such as polyester and polyimide are used as the support, the thickness of the support may be selected from the range of 10 to 500 // m.

The shape may be a substantially semi-cylindrical shape such as 1 in FIG. 1 (e) in addition to the flat plate shape. The radius of the semicircle in that case is in the range of 1 to 50 MI -You can choose from 1B-. Depends on the rigidity of the support and the photoconductive material layer, or on the radius of the semicircle, but is relatively rigid, such as a plate of glass, acrylic, or polycarbonate with a thickness of 1 In the case of a material having a high semi-cylindrical shape, it is preferable to previously process it into a desired semicylindrical shape. In the case of films such as polyester, the electrodes and the photoconductive layer may be formed in a state of being deformed into a cylindrical shape, or the electrodes and the photoconductive layer may be formed in a flat or wound shape. After forming, it may be held in a semi-cylindrical shape by cutting out to an appropriate size or the like.

 In particular, among the photoconductive layers to be described later, those mainly composed of an organic material generally have flexibility. Therefore, when combined with a support such as a polyester, which has a lithographic property, a planographic shape is obtained. After forming the electrode and the photoconductive layer in a wound shape, it is easy to deform into a semi-cylindrical shape.

 Among inorganic photoconductors, photoconductors such as amorphous silicon photoconductors and amorphous silicon photoconductors are made of inorganic material film by CVD or vacuum evaporation without using a binder. Is usually formed, but in these cases, the flexibility of the photoconductive layer is not so good, so that the photoconductive layer may be formed on a flexible support such as a polyimide film or a polyester film. When the electrode and the photoconductive layer are formed into a semi-cylindrical shape after forming the electrode and the photoconductive layer in a flat or wound shape, the thickness of the photoconductive layer is preferably set to m or less.

In addition, of the inorganic photoreceptors, inorganic powders such as cadmium sulfide and zinc oxide are mixed with an organic binder, and coated and formed. The flexibility in the case of the formed photosensitive layer is the portability between the above-described organic photoreceptor and the amorphous silicon or the amorphous selenium photosensitive member. Deformation into a semi-cylindrical shape with a radius of 2 m or more can be performed without any practical problems without reducing the thickness.

The photosensitive member electrode 4, for example, Te preparative La shea § Bruno onboard di meta emissions, organic conductive films such as Po Li acetylene les down, I T0, Zn O, S n0 2 , etc. of the metal oxide transparent electrode, Transparent electrodes formed of thin films of metals such as Au, Pt, and Pd can be used. The thickness may be about 100 to 100 θ〜, and the sheet resistance may be in the range of 100 to 1000 Ω / port.

 The formation method may be a conventional method such as plating, sputtering, vapor deposition, CVD, and firing after coating. The photoreceptor electrode may be any as long as it can transmit the active light of the photoconductive layer 5.

 When the photoconductive layer 5 is irradiated with light, the photoconductive layer 5

(Electrons, holes) are generated, and their carriers are conductive layers that can move the layer width. Especially when there is an electric field, the effect is remarkable. The material is composed of an inorganic photoconductive material, an organic photoconductive material, an organic-inorganic hybrid type photoconductive material and the like.

 Hereinafter, the photoconductive material and the method for forming the photoconductive layer will be described.

 (A) Inorganic photoconductor (photoconductor)

Inorganic photoreceptor materials include amorphous silicon, amorphous selenium, cadmium sulfide, and zinc oxide. (A) Amorphous silicone photoreceptor

 As an amorphous silicon photoreceptor,

 1) Amorphous silicon (a-Si: H)

 ②Fluorinated amorphous silicon (a—SF)

 In addition, in order to control the electric resistance of the photoconductive layer and to control the spectral sensitivity characteristics, carbon C and nitrogen N are included during formation.

 ③ Hydrogenated amorphous silicon carbide (a—SiC: H)

 ④Hydrogenated amorphous silicon nitride (a—SiN: H)

 · Do not dope impurities to these,

 • B, A 1, Ga, In, T 1, etc. are made P-type (hole transport type) by doping.

 • Doping of P, Ag, Sb, Bi, etc. into U type (electron transport type),

 There is.

As a method for forming the photoconductive layer, silane gas, an impurity gas together such as hydrogen gas was introduced into the low vacuum ^{(1 0_ 2 ~1 T or r} ), sedimentary for heating, or heating and no electrode on a substrate by glow one discharge Either a single layer or a stacked layer is formed by depositing a solid raw material by vapor deposition or sputtering, or by simply forming a thermochemical reaction on a heated electrode substrate. The thickness is 1 to 50 m.

In addition, in order to prevent charge from being injected from the photoreceptor electrode 4 and being exposed as if it were not exposed, a charge injection prevention layer may be provided on the surface of the photoreceptor electrode 4. it can. As the charge injection preventing layer, an a-SiN layer, an a-SiC layer, or a Si0 _{It is} preferable to provide _two insulating layers, such as an Al ₂ O ₃ layer. If this insulating layer is too thick, no current will flow when exposed, so it needs to be at least 1 000 or less, and about 400 to 500 A is desirable in consideration of ease of fabrication.

In addition, as a charge injection preventing layer, a charge transport layer having a charge transporting ability of a polarity opposite to the polarity of the electrode substrate may be provided on the electrode substrate by using a rectifying effect, and when the electrode is negative, hole transport is performed. If the layers and electrodes are positive, an electron transport layer is provided. For example, aSH (n ⁺ ), in which Si is doped with boron, has an improved hole transporting property and a rectifying effect, and functions as a charge injection preventing layer.

 (Mouth) Amorphous photoreceptor

As amorph ₇ selenium photoreceptor,

 ① Amorphous selen (a-Se)

 ②Amorphous selentellurium (a-Se-Te)

③Amorphous arsenic selenium compound (a-As ₂ Se ₃ )

モ ル Amorphous arsenic selenium compound + Te

There is.

Photoreceptor This deposition, to prepare Ri by the sputter coater method, also _{Si0 2, A 1 2 0 3} , SiC as electrostatic charge injection blocking layer, depositing a SiN layer, the electrode substrate by sputtering coater, glow one discharge method Provided above. Combining the above ① to ④ to form a stacked photoreceptor Good. The thickness of the photoconductor layer is the same as that of the amorphous silicon photoconductor-© 0

 (C) Cadmium sulfide (CdS)

 This photoreceptor is manufactured by a coating, vapor deposition, or sputtering method. In the case of vapor deposition, solid particles of CdS are placed on a tungsten board, and vapor deposition is performed by resistance heating or EB (electron beam) vapor deposition. In the case of sputtering, a CdS target is deposited on the substrate in an argon plasma. In this case, CdS is usually deposited in an amorphous state, but a crystalline alignment film (oriented in the film thickness direction) can be obtained by selecting sputtering conditions. In the case of coating, CdS particles (particle diameter m) may be dispersed in a binder, and a solvent may be added to coat on the substrate.

 In this case, silicone resin, styrene-butadiene copolymerized resin, epoxy resin, acryl resin, saturated or unsaturated poly- ol may be used as the binder. Steal resin, polycarbonate resin, polybutylacetal resin, X-nor resin, polymethylmethacrylate (PMMA) resin, melamine resin, polyimide resin, etc. Should be used.

 The amount of CdS to be added is a weight ratio, and the binder: CdS = l: 3-1: 1: 10 may be used.

For coating on a semi-cylindrical substrate, a method such as dip coating or casting can be applied, and blade coating using a blade having a semi-cylindrical shape and an appropriate gap can be applied. Go You may.

 The film thickness may be in the range of 3 to 100 Wm.

 (2) Zinc oxide ({η})

 This photoreceptor is manufactured by a coating method or a CVD method. The coating method is obtained by dispersing {η} particles (particle size: 0.1 to ljtzm) in a binder, adding a solvent, and coating the substrate.

 In this case, as binders, silicone resin, styrene-butadiene copolymer resin, epoxy resin, acryl resin, saturated or unsaturated polyester resin, poly A carbonate resin, a polyacetal resin, a phenol resin, a PMMA resin, a melamine resin, a polyimide resin, or the like may be used.

 The amount of ZnO to be added is a weight ratio, and the binder: η0 = 1: 3—1: 1: 10 may be used.

 Further, the film thickness may be in the range of 3 to 100 / zm.

The coating method on the semi-cylindrical substrate may be performed in the same manner as in the case of the sulfur doping. The CVD method also, di- E chill zinc, an organic metal and oxygen gas, such as dimethyl chill zinc mixed with low-true air (10_ ² ~ 1 Torr), heated electrode substrate (150

(~ 400 ° C) and deposit as zinc oxide film. Also in this case, a film oriented in the film thickness direction can be obtained.

 (B) Organic photoreceptor

Organic photoconductors include single-layer photoconductors and function-separated photoconductors. (B) Single-layer photoreceptor

 Single-layer photoreceptors consist of a mixture of a charge generating material and a charge transport material.

Charge generating substance system>

 It is a substance that absorbs light and easily generates electric charge. Examples of such materials include azo pigments, disazo pigments, trisazo pigments, phthalocyanine pigments, perylene pigments, and pyridine pigments. Lime dyes, cyanine dyes, and methine dyes are used.

 Charge transport material system>

 It is a substance that has good transport properties of ionized electric charges, such as hydrazone, virazoline, polybulphyrazole, tylazole, stilbene, anthracene, and naphthalene , Trifluoromethane, azine, amine, and aromatic amines.

 Alternatively, a charge transfer complex may be formed by forming a complex with a charge generation material and a charge transport material.

 Normally, photoconductors have photosensitivity determined by the light absorption properties of the charge-generating substance. However, when the charge-generating substance is mixed with the charge transport substance to form a complex, the light-absorption properties change, for example, polycarbazole ( (PVK) only feels in the ultraviolet region, and Trinitrofluorenone (TNF) only feels near the 400 nm wavelength, while the PVK-TNF complex feels up to the 650 nm wavelength range.

 The thickness of such a single-layer type photoreceptor is preferably from 10 to 50 // m.

(Mouth) Photoreceptor with separate function The charge-generating substance easily absorbs light, but has a property of trapping light. The charge-transporting substance has good charge-transporting properties, but not good light-absorbing properties. For this reason, they are separated from each other, and the characteristics of each are fully exploited. This is a type in which a charge generation layer and a charge transport layer are stacked.

 Charge generation layer>

 Examples of the substance that forms the charge generation layer include azo-based, disazo-based, trisazo-based, phthalocyanine-based, acidic xanthane dye-based, cyanine-based, styrene-based dyes, and the like. There are a pyrium dye type, a perylene type, a methine type, a-Se, a-Si, an azulhenium salt type and a squarium salt type.

 Charge transport layer>

 Examples of the substance forming the charge transport layer include hydrazone-based, pyrazoline-based, PVK-based, carbazole-based, oxazole-based, triazole-based, aromatic amine-based, and amine-based substances. , Triphenyl methane, and polycyclic aromatic compounds.

 As a method for producing a function-separated type photoreceptor, first, a charge generating substance is dispersed or dissolved in a binder together with a solvent, and then spin-coated, rono-recording, wireless coating, and brazing. Apply it on the electrode by do coating, spray coating, dip coating, etc., and then dissolve the charge transport layer together with the solvent in the binder. It is preferred that the charge generation layer is applied to a thickness of 0.1 to 5 jtzm and the charge transport layer is applied to a thickness of 2 to 50 μm.

In the case of a single-layer type photoreceptor or a function-separated type photoreceptor, The binders are silicone resin, styrene-butadiene copolymer resin, epoxy resin, acrylic resin, saturated or unsaturated polyester resin, and polycarbonate resin. , Polyvinyl acetate resin, phenol resin, polymethylmethacrylate (PMMA) resin, melamine resin, polyimide resin, etc. And 10 parts of Q.l to 10 parts of each charge transport material to facilitate adhesion. As the coating method, in addition to the above-described wet coating, a dry coating method such as an evaporation method, a sputtering method, and a CVD method can be used.

 In the case of the function-separated type photoreceptor, the charge retaining layer and the charge transport layer may be stacked in any order on the transparent electrode. However, since exposure is performed from the electrode side, when a charge transport layer having low transparency to active light for exposure is used, it is preferable to first provide a charge generation layer on the electrode side.

 Next, the charge injection preventing layer will be described in detail.

 The charge injection prevention layer is not exposed to at least one or both surfaces of the photoconductive layer 5, that is, dark current (charge injection from the electrode) when a voltage is applied to the photoconductive layer 5, that is, not exposed. Nevertheless, it can be provided to prevent a phenomenon in which charges move in the photosensitive layer as if exposed.

This charge injection prevention layer has two types, a layer using an insulating thin film and a layer using a rectifying effect. First, in the case of using an insulating thin film, current flows to the photoconductive layer or the resin layer surface by the charge injection prevention layer only by applying voltage. However, when light is incident, a high electric field is applied to the charge injection prevention layer corresponding to the incident part because one of the charges (electrons or holes) generated in the photoconductive layer is present, and charge injection occurs. The current flows through the prevention layer. Such a charge injection prevention layer is formed of a single layer such as an inorganic insulating film, an organic insulating polymer film, an insulating monomolecular film, or the like, or is formed by laminating them. _{As 2 0 3, B 2 0} 3, Bi 2 0 3, CdS, CaO, Ce0 2, Cr 2 0 3, CoO, Ge0 2, Hf 0 2, Fe 2 0 3, La s 0 3, HgO, Mn0 2 _{, Nd 2 0 3, Nb 2} 0 6, PbO, Sb 2 0 3, Si0 2, Se0 2, Ta 2 0 5, Ti0 2, W0 3, V 2 0 5, Y 2 0 5, Y 20 3, Zr0 _{2, BaTi0 3, Al 2 0} 3, Bi 2 Ti0 6, CaO-SrO, Ca O-Y2 O3, Cr-SiO, LiTaOa, PbTi0 3, PbZr0 3, Zr0 2 -Co

_{, Zr0 2 -Si0 2, A1N,} BN, NbN, SiaN ^, TaN, is formed TiN, VN, ZrN, SiC, TiC, ffC, AI4C3 like glow one discharge, vapor deposition, the spatter Li in g etc. . The thickness of this layer is determined depending on the material to be used in consideration of the insulating property for preventing charge injection, but is usually in the range of 0.01 to 10 m, preferably 0.05 to l / zm. Selected.

Next, the charge injection preventing layer utilizing the rectifying effect is provided with a charge transporting layer having a charge transporting ability having a polarity opposite to the polarity of the electrode substrate utilizing the rectifying effect. That is, such a charge injection preventing layer is formed of an inorganic photoconductive layer, an organic photoconductive layer, and an organic-inorganic hybrid photoconductive layer, and has a thickness of about 0.01 to 10 / zm. More specifically, when the electrode is negative, amorphous silicon photoconductive rhinoceros with amorphous B, A1, Ga, In, etc., or amorphous Selenium, or oxaziazol, pyrazoline, polyvinyl carnosol, stilbene, anthracene, naphthalen, triphenylmethane, triphenyl Organic photoconductive layer formed by dispersing phenylmethane, azine, amine, aromatic amine, etc. in resin, and P, N, As, Sb when the electrode is positive An amorphous silicon photoconductive layer, a ZnO photoconductive layer, and the like doped with Si, Bi, etc. are formed by a method such as glow discharge, vapor deposition, sputtering, CVD, and coating.

 The distance d is usually about 10 jwm, but d = 0, that is, the photoconductive layer 5 and the charge holding layer 6 may be in close contact.

 The conductive substrate 7 needs to function as an electrode during voltage application exposure, and since it is used as a lithographic printing plate, at least the surface must have a hydrophilic property, so that it is 0.3 mm. A grained aluminum plate of moderate thickness can be used. The use of a directly grained aluminum plate as the conductive substrate 7 is particularly advantageous for large-area printing, but in the case of printing having a small area such as a postcard printing. For example, as shown in FIG. 2, an aluminum substrate 13 having a thickness of 1,000 A to lm is formed on an insulating substrate 18 such as a glass by vapor deposition or the like. Zinc can be used in addition to aluminum.

The requirement for the charge retention layer 6 is that the charge retention layer 6 has not only charge retention properties, but also can be removed by appropriate etching, and has lipophilicity because it forms the image area of the printing plate. , Update In addition, the material must have printing durability, that is, have mechanical strength. For example, the following materials can be used. The thickness may be about 2 to 10 tm.

Since the charge retention layer 6 records information on the surface or inside thereof as a distribution of static charges, it needs to have high insulation properties to suppress the movement of charges, and the specific resistance is 10 ¹⁴ It is required to have an insulating property of Ω'cm or more. Such a charge retaining layer 6 may be formed by dissolving a resin or rubber in a solvent and coating or dating, or by vapor deposition or sputtering. Can be.

 Here, as the above resin and rubber, for example, polyethylene, polypropylene, bur resin, styrene resin, acrylic resin, nylon 66, nylon 6, poly Carbonate, acetate resin, fluorine resin, cellulose resin, phenol resin, urine resin, polyester resin, epoxy resin, portable epoxy resin, Min resin, silicone resin, phenoxy resin, aromatic polyamide, PP0, polysulfone, etc., as well as polyisoprene, polybutadiene, and polybutadiene. Recycling plane, isobutylene, extra-high trill, polyacrylic rubber, chlorosulfonidai polyethylene, ethylene propylene wrapper, Fluoro rubber, silicon wrapper, polysulfide synthetic rubber, c A simple substance or a mixture of rubber such as tan rubber is used.

In addition, as materials for the charge retention layer 6, cellulose acetate succinic acid semi-ester and polyvinylpyrridine (used as eluent) Dilute aqueous alkali solution can be used, hereinafter, the parentheses indicate the eluate), partially genated polyvinyl acetate (water), partially genated polyvinyl acetate adduct and polyvinyl alcohol N is 6 or more such as poly (ethylene glycol) / adipic acid / fumaric acid polycondensate, poly (ethylene glycol) / polyurethane tampon (dilute aqueous alkali solution) Unsaturated polyesters such as polystyrene and polyester modified with polyethylene glycol, such as phenylenediocyanate and phenylenediocyanate. Aqueous alcoholic solution), alcohol-soluble polyamides (alcohols), such as polycondensates of ε-capillary hexamethylenediamine / adipinate ), Ε—force pro- gram Ν, Ν '—Cathion-type water-soluble polyamide (water), such as polycondensate of bis (-aminopropyl) piperazine and adipic acid, and polyamide-methylene Diamin * Water-soluble anion-type polyamides (water), such as polycondensates of terephthalate and sodium isophthalate sulfonate, water Polyethylene glycol and adipic acid are reacted with a medium, followed by glycidyl methacrylate. Polyether amide (water), styrene-isoprene-styrene block polymer, styrene-butadiene-styrene block polymer, nitrile rubber, syn-1 , 2-—Polybutadiene and other thermoplastic polymers (halogenated hydrocarbons) Ternary block polymer (aqueous sodium carbonate solution), such as crylonitrile butadiene acrylate block polymer, polystyrene Sop Block polymers such as styrene block polymers (halogenated hydrocarbons), Asahi Glass Co., Ltd. solvent-soluble fluorine resin (trade name: CYTOP) (special solvent), Polycarbonate resin (1-1-2 trichlorethane), silicone varnish such as TSR144 (Xylene) manufactured by Toshiba Silicone Corp. can be used. It is. After elution, baking at 150 ° C. for about 30 minutes may be performed to improve the printing durability.

 The voltage of the power supply 8 only needs to be DC 1500 1500 volts. For example, if a positive voltage is applied to the electrode 4 as shown in FIG. 1, a positive charge pattern is formed on the charge holding layer, and It can be developed with charged toner particles.

 Laser light and ultraviolet light can be used as the exposure light source. Visible light such as a tungsten lamp or a halogen lamp may be used. For example, when using an a-Se photoreceptor in which 30 m of a-Se is laminated on an a-SeTe charge generation layer with a thickness of 5000 A, the color temperature is about 4000. It is sufficient to expose the light of the K tungsten lamp to about 50 lux for 0.1 second.

 The toner can be used with either a dry toner or a wet toner, but the dry toner has a relatively large particle size of about 10 to 30 / zm and is inferior in resolution, but the wet toner has a particle size of 0.1 to As small as about 3 m, it is possible to obtain sufficient resolution.

5

The temperature for fixing the toner may be a wet type toner disclosed in Japanese Patent Publication No. 58-2851. In this case, the temperature is 100, and the fixing condition is about 2 to 5 minutes. Good. Sufficient fixing is performed under the same conditions in the case of a general dry toner.

 Further, the fixed toner image is used as a resist, and the charge holding layer other than the toner image is removed by etching. Etching can be performed by using a solvent that dissolves the charge-retaining layer material, eluting and removing the charge-retaining layer in portions other than the toner image, or by using a plasma incinerator to cover the toner in the charge-retaining layer. It is also possible to use a photo-decomposable resin, for example, a positive photo resist, as the charge retention layer material. Irradiation (for example, ultraviolet rays) and further development may be employed to remove any portion of the charge retaining layer that is not covered with the toner, such as a method of removing the portion.

 When the charge retaining layer in the portion other than the toner image is removed by the printing in this way, the electrode 7 is exposed, and further, if necessary, a processing such as a touching process or a rubber coating is performed. Is also good.

 [Example 1]

 The surface of a 0.3-dragon-thick aluminum plate was grained by ball polishing, and the surface was washed with the following surface-regulating liquid and washed with water.

 Phosphoric acid I Bec

 Water l O O Occ

 Further, it was treated with the following hydrophilizing solution, washed with water and dried.

 Aluminum bichromate 1 350 g

 Water 20 S

Hydrofluoric acid 48% IG Occ Next, a 5% solution of acrylonitrile blocker-acrylic acid block polymer in toluene is spin-coated on this aluminum plate and dried. After forming a 3 m-thick coating film, it was dried in an oven at 100 ° C. for 30 minutes to form a plate.

 On the other hand, a transparent conductive film was obtained by forming an IT0 film having a thickness of 500 A on a glass plate having a thickness of 3 urn by a sputtering method. The sheet resistance was 1000 Ω / □.

On top of this, to form a Si0 ₂ Ri by the Supadzu data method 1000A thickness, to form a charge injection preventing layer.

 Furthermore, an a-SeTe charge generation layer having a thickness of 5000 A was formed by a vacuum deposition method. The Te content was U.5 wt%.

 Further, an a-Se layer having a thickness of 30 m was similarly formed as a charge transport layer by a vacuum evaporation method to obtain a photoreceptor.

 Next, a gap was formed and the photosensitive member was pressed on the above-described plate by partially forming a 3 mm-thick polyester film. The measured gap was 12 m. Next, a 150-line / inch net positive film was placed on the photoreceptor and brought into close contact. +800 V was applied to the transparent electrode on the photosensitive plate side, and the aluminum plate side was grounded.

 Light was applied to a tungsten lamp with a color temperature of 4000 ° K so that the light became almost parallel. It was about 50 lux on the photosensitive plate. After closing the switch for 0.1 second, the plate was removed.

An electrostatic latent image of +170 V was formed on the plate. This latent image is subjected to inversion development with a wet toner disclosed in JP-A-58-2851, and after drying, fixed in an oven at 100 ° C for 5 minutes. went.

 Further, elution was carried out with a 5% aqueous solution of sodium carbonate, followed by washing with water and drying to form a lithographic printing plate.

 Offset printing was performed using an offset proof press while supplying dampening water.As a result, it was confirmed that 3 to 9 B% of 150 lines / inch was printed. Was done.

 [Example 2]

 The plate prepared in the same manner as in Example 1 was mounted on an offset rotary printing press to print 100,000 sheets. No damage was found on the printing plate.

 In the above example, only one printing plate was manufactured. However, if the printing plate is for color printing, the printing plate for Y, the printing plate for M, and the printing plate for C are printed in the same manner as described above. It is natural that it is necessary to manufacture four types of printing plates, a printing plate and a printing plate for K.

 Next, a plate collection system using the charge holding medium according to the present invention will be described. First, a charge holding medium, a voltage application exposure method, and an electrostatic latent image formed on the charge holding medium used in the plate collection system are described. Will be described. FIG. 3 is a diagram for explaining an image recording method using a charge holding medium. In the figure, 21 denotes a charge holding medium, 22 denotes a photoconductor, and E denotes a power source.

The charge holding medium 21 is formed, for example, by depositing a 1,000-layer thick A 1 film on an insulating layer support 21 c made of a 1-M thick glass by vapor deposition to form a charge holding medium electrode 21 b, Furthermore, the charge storage medium electrode 2 1 It is formed by forming an insulating layer 21a having a thickness of 10 tz on b. The photoreceptor 22 includes a photoreceptor support 22a, a photoreceptor electrode 22b, and a photoconductive layer 22c as in the case of the photoreceptor 1 in FIG. A transparent photoreceptor electrode 22b made of IT0 having a thickness of 1000 A is formed on the support 22a, and a photoconductive layer 22c having a thickness of about 10 / zm is further formed thereon. it can

 FIG. 3 shows an embodiment in which exposure is performed from the photoreceptor 22 side. First, as shown in FIG. 3 (a), the charge holding medium is spaced from the photoreceptor 22 through a gap of about 10βm. Then, a predetermined voltage is applied between the photoreceptor electrode 22b and the charge holding medium electrode 21b by the power source E as shown in FIG. In a dark place, the photoconductive layer 22c is a high-resistance material, so that no change occurs between these two electrodes. The conductive layer 22c exhibits conductivity, discharge occurs between the conductive layer 22c and the insulating layer 21a, and electric charges are accumulated in the insulating layer 21a. This is exposure.

 When the exposure is completed, the power supply E is disconnected as shown in FIG. 3 (c), and then the charge holding medium 21 is taken out as shown in FIG. 3 (d), thereby forming the electrostatic latent image. The formation ends.

The photoreceptor 22 and the charge holding medium 21 do not need to be in non-contact as shown in FIG. 3, and may be a contact type. Positive or negative charges are injected into the exposed portion of the layer 22c, and the charges are drawn by the electrode 21b on the charge holding medium 21 side, pass through the photoconductive layer 22c, and become When the charge reaches the surface, the charge transfer stops, and the injected charge accumulates at that position. Then, when the photoconductor 22 and the charge holding medium 21 are separated from each other, the insulating layer 21a is separated in a state where the charge is accumulated.

 In this recording method, high resolution can be obtained in the same manner as silver halide photography in the case of planar analog recording, and the surface charge on the formed insulating layer '2 ia is exposed to the air environment, but air is good. Because of its excellent insulation performance, it can be stored for a long period of time without discharging regardless of light or darkness.

 The charge storage period on the insulating layer 2ia is determined by environmental conditions and the properties of the insulator, and is affected by the charge trapping characteristics of the insulator in addition to the insulating properties of air. In the above description, charges are described as surface charges.However, injected charges may simply accumulate on the surface, and microscopically penetrate into the vicinity of the insulator surface, causing electrons or electrons to enter the structure of the substance. In some cases, holes are trapped, so long-term preservation takes place. The surface of the insulating layer 2ia may be covered with an insulating film or the like in order to prevent physical damage to the charge holding medium or discharge when the humidity is high.

 Next, a method for recording color image information will be described with reference to FIGS. 4 (a) and 4 (b).

In FIG. 4 (a), the original 25 is illuminated by the light source 23 or 24, and the reflected light or transmitted light is surface-exposed to the photoreceptor 22 via the color filter 2B and recorded on the charge holding medium 21. Color filter 2B has three components: red (R :), green (G :), and blue (B). This is moved horizontally to select R, G, and B, and the recording of one color image information is completed with one set of three charge holding media.

 4 (b) is the same as that of FIG. 4 (a) except that a rotary color filter 27 is used and R, G, B are selected by rotation of the color filter 27.

 An example of reading the potential of the electrostatic latent image thus recorded will be described with reference to FIG.

 FIG. 5 (a) is a diagram showing an example of a potential reading method, and the same components as those in FIG. 3 are denoted by the same reference numerals. In the figure, 30 is a potential reading section, 31 is a detection electrode, 32 is a guard electrode, 33 is a capacitor, and 34 is a voltmeter.

When the potential reading section 30 is opposed to the charge storage surface of the charge storage medium 21, an electric field generated by the charge stored on the insulating layer 21a of the charge storage medium 21 acts on the detection electrode 31, and the detection electrode 31 An induced charge equal to the charge on the charge holding medium 21 is generated on the surface. Since the capacitor 33 is charged with the same amount of charge having the opposite polarity to the induced charge, a potential difference corresponding to the accumulated charge is generated between the electrodes of the capacitor 33, and this value is read by the voltmeter 34. Thus, the potential of the charge holder 21 can be obtained. By scanning the surface of the charge holding medium 21 with the potential reading unit 30, an electrostatic latent image can be output as an electric signal. In addition, since the electric field (line of electric force) due to electric charges in a wider range than the detection electrode facing portion of the charge holding medium 21 acts on the detection electrode 31 alone to reduce the resolution, the detection electrode 31 is grounded around the detection electrode 31. Guard electricity The pole 32 may be arranged. As a result, the lines of electric force are directed perpendicular to the surface, so that the lines of electric force only act on the portion facing the detection electrode 31, and the area of the detection electrode 31 is substantially reduced. The potential of the same part can be read. Since the accuracy and resolution of potential reading vary greatly depending on the shape and size of the detection electrode 31 and guard electrode 32 and the distance between the electrode and the charge retention medium 21, the optimal conditions are designed to meet the required performance. There is a need to.

 FIG. 5 (b) shows another example of the potential reading method, in which the detection electrode 31 and the guard electrode 32 are provided on the insulating protective film 35, and the potential is detected via the insulating protective film 35. It is the same as the case of Fig. 5 (a) except that is detected. According to this method, since the detection can be performed by contacting the charge holding medium 21, the distance from the detection electrode 31 can be made constant.

 FIG. 5 (C) shows another example of the potential reading method, in which the needle electrode 3B is brought into direct contact with the charge holding medium 21 to detect the potential at that portion, and the detection area is small. High resolution can be obtained. The reading speed can be improved by providing a plurality of needle electrodes 36 for detection.

 The above is a DC amplification type in which a DC signal is detected in a contact or non-contact manner. Next, an example of an AC amplification type will be described.

 FIG. 5 (d) is a diagram showing a method of reading the potential of the vibrating electrode type, wherein 37 is a detection electrode, 38 is an amplifier, and 39 is a meter.

The detection electrode 37 vibrates and contacts the charged surface of the charge holding medium 21. Vibration is performed so that the distance changes over time. As a result, the potential of the detection electrode 37 changes over time with an amplitude corresponding to the electrostatic potential of the charged surface. This temporal potential change is taken out as a voltage change across the impedance Z, the AC component is amplified by the amplifier 38 through the capacitor C, and read by the meter 33 to measure the electrostatic potential of the charged surface. be able to.

 Fig. 5 (e) shows an example of a rotary detector, in which 40 indicates a rotating blade.

 A conductive rotating blade 40 is provided between the detection electrode 37 and the charged surface of the charge holding medium 21 and is rotationally driven by vibration means (not shown). As a result, the space between the detection electrode 37 and the charge holding medium 21 is periodically electrically shielded. Therefore, a potential signal whose amplitude changes periodically according to the electrostatic potential of the charged surface is detected at the detection electrode 37, and this AC component is amplified by the amplifier 38 and read.

 Fig. 5 (f) shows an example of a vibration capacitance type detector, in which 41 is a drive circuit and 42 is a resonator element.

 The drive circuit 41 vibrates the vibrating reed 42 of one of the electrodes forming the capacitor to change the capacitor capacity. As a result, the DC potential signal detected by the detection electrode 37 is modulated, and the AC component is amplified and detected. This detector converts DC to AC and can measure potential with high sensitivity and stability.

Fig. 5 (g) shows an example of a current-collecting detector, in which 43 is a grounded metal cylinder, 44 is an insulator, and 45 is a current collector. The current collector 45 contains a radioactive substance, from which radiation is emitted. As a result, air is ionized in the metal cylinder to form positive and negative ion pairs. In the natural state, these ions disappear by recombination and diffusion, and remain in an equilibrium state.However, when an electric field is present, the ions repeatedly impact with air molecules due to thermal motion and statistically move in the direction of the electric field. It plays the role of moving forward and carrying charges. In other words, the air is made conductive by the ions, and it can be considered that an equivalent electric resistance path exists between the surrounding objects including the current collector 45. Accordingly, the resistance between the charged surface of the charge holding medium 21 and the grounded metal cylinder 43, the charged surface and the current collector, and the resistance between the current collector 45 and the grounded metal cylinder 43 are respectively R ₀ , Ri, R ₂ , and the potential of the charged body. V, the potential V ₂ of the current collector 45 is V ₂ = R ₂ V, / (R! + Rs) in a steady state. As a result, the potential of the charge holding medium 21 can be obtained by reading the potential of the current collector 45.

 FIG. 5 (h) is a diagram showing an example of an electron beam type potential reader, wherein 4B is an electron gun, 47 is an electron beam, 48 is a first dynode, and 49 is a secondary electron multiplier.

Electrons emitted from the electron gun 46 are deflected by an electrostatic deflecting device or an electromagnetic deflecting device (not shown) to scan the charged surface. A part of the scanning electron beam is combined with the charge on the charged surface, and the charging current flows, and the potential on the charged surface drops to the flat street potential. The remaining modulated electron beam returns to the direction of the electron gun 48, strikes the first dynode 48, and the secondary electrons are amplified in the secondary electron multiplier 49, and the signal is output from the anode as the signal output. Taken out. This Use reflected electrons or secondary electrons as the returning electron beam.

 In the case of the electron beam type, a uniform charge is formed on the medium after scanning, but a current corresponding to a latent image is detected during scanning. When the latent image is a negative charge, the charge accumulated by the electron is small and the charge current is small in a portion having a large amount of charge (exposed portion), but is small in a portion where no charge exists, for example. Charging current flows. In the case of a positive charge, the reverse is true and the result is a negative type.

 FIG. 5 (i) is a diagram showing another example of the potential reading method, in which the charge holding medium 21 on which the electrostatic latent image is formed is developed with toner, and the colored surface is irradiated with a light beam and scanned. The reflected light is converted into an electric signal by the photoelectric converter 50.By reducing the light beam diameter, high resolution can be achieved, and optically simple operation is achieved. Then, the electrostatic potential can be detected in a short time.

 FIG. 5 (j) is a diagram showing another example of the potential reading method, in which the R, G, and B separation images formed by a fine color filter as described later are developed with toner and colored. The figure shows an example of irradiating a laser beam with a light beam and obtaining Y, M, and C signals from the reflected light. In the figure, 51 is a scanning signal generator, 52 is a laser, 53 is a reflecting mirror, 54 is a half mirror, 58 is a photoelectric converter, and 55, 5B, and 57 are gate circuits.

The scanning signal from the scanning signal generator 51 applies the laser beam from the laser 52 to the colored surface via the reflecting mirror 53 and the half mirror 54. Scan normally. The reflected light from the colored surface enters the photoelectric converter 58 via the half mirror 54 and is converted into an electric signal. If the gate circuits 55, 56, 57 are controlled to open and close in synchronization with the signal from the scanning signal generator 51, the gate circuits 55, 56, 57 are controlled to open and close in synchronization with the pattern of the fine filter. Therefore, Y, M, and C signals can be obtained without coloring Y, M, and C.

 In the case where the color image is divided into three planes as described later, the Y, M, and C signals can be obtained in exactly the same manner. In this case, the Y, M, and C signals need not be colored. The same is true.

 In the electrostatic potential detection method shown in FIGS. 5 (i) and (j), the toner image needs to have seven characteristics corresponding to the charge amount of the electrostatic latent image, and therefore, the It is necessary to have no threshold value for the analog change of quantity. As long as the measures are taken, even if the characteristics do not match, it is sufficient to carry out the correction of 7 by electrical processing.

 FIG. 5 (k) shows another example of the potential reading method. That is, the method is such that the lines of electric force generated by the electrostatic charge act on the electro-optic material 130, and the change generated in the electro-optic material 130 is read by the light sensor 131 with the light 132.

The electro-optic material 130, it is that you use LiNbO _3, a liquid crystal or the like. The light 132 uses polarized light as needed, and the optical sensor 131 also incorporates a polarizing plate as needed.

In FIG. 5 (k), the case where the charge holding medium 21 is transparent is illustrated, but the reflected light is converted using the same optical system as in FIGS. 5 (i) and (j). Needless to say, it can be detected. Further, the light 132 and the optical sensor 131 may be fixed and the charge holding medium 21 may be scanned, or the light 132 and the optical sensor 131 may be scanned conversely. Alternatively, an image sensor may be used as the optical sensor 131, and an image may be formed on the image sensor using a lens. Next, a color filter used for forming a color image will be described.

 Fig. 6 shows a color separation optical system 68 using a prism. In the figure, 80, 61, and 62 are prism blocks, 63, 64, and 65 are filters, and B6 and B7 are reflection mirrors. It is.

 The color separation optical system 68 is composed of three prism blocks B0, 61, and B2. The light information incident from the a surface of the prism block B0 is partially reflected on the b surface, and is further reflected on the a surface. Then, the B color light component is extracted from the filter 63. The remaining light information is incident on the prism block 61, travels to the c-plane, and is partially reflected and separated, and the G color component from the filter 64 and the other goes straight to the R color component from the filter 65. Taken out. The G, B light components are reflected by the reflecting mirrors 66, 67, so that the R, G, B light can be extracted as parallel light.

By arranging the color separation optical system B8 as shown in FIG. 6 and photographing it in front of the photoreceptor 22 as shown in FIG. 7 (a), the image as shown in FIG. 7 (b) is obtained. One frame is formed by three sets of the R, G, and B decomposed charge holding media. Alternatively, as shown in Fig. 7 (c), one set of R, G, and B images is arranged on one plane. Each frame can be one frame. FIG. 8 is a diagram showing an example of a fine color filter. For example, a mask obtained by coating a register with a mask. The pattern is formed by exposing in turns to form R, G, B stripe patterns and dyeing them by R, G, B, respectively, or the light separated by the method shown in Fig. 6 A method in which R, G, and B interference fringes generated by passing through a narrow slit are recorded on a hologram recording medium, or R, G, and B stripes are formed by an electrostatic latent image. A pattern is formed, this is developed by toner, transferred three times, and then color-combined to form a toner stripe. One pixel is formed by a set of filters R, G, and B formed by such a method, and one pixel is made as fine as about 10 m. A color electrostatic latent image can be formed by using this filter as the color separation optical system 68 in FIG. In this case, the filter may be disposed separately from the photoconductor, or may be formed on the photoconductor.

Fig. 9 shows an example in which a fine color filter and a Fresnel lens are combined. The R, G, and B patterns can be reduced and recorded by the Fresnel lens 63. A thin and compact lens design is possible compared to a normal lens. Fig. 10 shows an example of three-plane division using a half mirror and R, G, and B filters together. The incident light is split by half mirrors 71 and 72 and reflection mirror 73. R, G, and B light can be extracted as parallel light by splitting and passing through R filter 74, G filter 75, and B filter 76, respectively. Next, as a method for erasing the electrostatic latent image formed on the charge holding medium, there is the following method.

 (1) Using the same pattern as the exposure pattern for forming a latent image, or using a pattern whose lightness and darkness are opposite to those of the exposure pattern, and performing exposure by applying a voltage with a polarity opposite to the polarity applied when forming the latent image. .

(2) Exposure by applying a voltage of the same polarity or the opposite polarity during latent image formation and irradiating uniform light.

 (3) Heating by appropriate heating means such as infrared heating, resistance heating, microwave heating, and thermal head heating.

方法 A method of exposing with ultraviolet rays using the same pattern as the exposure pattern used when forming a latent image.

 (4) A method of performing uniform exposure using ultraviolet light.

 (4) A method in which the conductive member is scanned while being in contact with the surface of the charge holding medium.

(4) A method of attaching moisture to the surface of the charge holding medium.

 (4) A method in which electrodes are brought close to each other and a voltage of the same or opposite polarity is applied.

 Although the electrostatic latent image can be erased by these methods, when erasing the electrostatic latent image formed on a part of the charge holding medium, other parts other than the part to be erased are used. And can be erased by any of the above methods.

 Next, an embodiment of a plate collecting system using the charge holding medium according to the present invention will be described.

Prior to the plate collecting operation, the charge holding medium 21 and the photoreceptor 22 are prepared. Then, as shown in Fig. 11, the image of the original Is exposed from the photoreceptor 22 side as a magnification specified by the appropriate lens system 81 on the layout sheet, for example, an original size. Thus, an electrostatic latent image of the image of the document 80 is formed at a predetermined position of the charge holding medium 21. If this operation is performed for all the originals assigned to the page, the originals used for the page can be collected. At this time, the size of the charge holding medium 21 and the photoreceptor 22 may be any size as long as the image of the document can be exposed to a designated size, in this case, that is, an original size. By reading the potential, the original size image data is taken into the image processing device to perform density adjustment, color tone adjustment, trimming, etc., and finally input to the color scanner and output to the film However, it is particularly preferable to use the same size as the layout sheet because the image of the document used for the page can be allocated and exposed at the position specified on the layout sheet. . It is recommended that the exposure of the original image be made larger than the trimming range specified on the layout sheet. In addition, in order to expose the original image at the specified magnification and direction at the position specified on the layout sheet, it is possible to use a conventionally used image projection device or the like.

^ Paruru.

It is also important to expose the original image to its original size, that is, the size specified on the layout sheet. Of course, the size of the original image to be exposed is arbitrary. For example, it is possible to reduce the size of the original image to 1/2 of the designated size and expose the original image. However, there are various problems. In other words, when exposing to the original size, the designated magnification value may be used as it is, but when reducing and exposing, the magnification value must be reduced by 1/2 each time. It is easy to cause a setting error. This is particularly remarkable when the electrostatic latent image obtained by the exposure is erased and the exposure is repeated. In full-scale exposure, the image data can be used as it is when exposing the output film with a color scanner, as well as image processing described later. Is required to perform enlargement processing when outputting to a film, which not only increases the time required for image processing, but also requires hardware for enlargement processing. It causes rise. Even if the cost increase and processing time for the enlargement process were negligible, it would be clear that a full-scale exposed image would be better than a reduced and enlarged image. In addition, full-scale exposure is advantageous for reading the potential of the charge holding medium. The reason for this is that, when a reduction exposure is performed, the magnification must be finally increased, so that the density of the read pixels must be increased compared to the full-size exposure, and the cost of the read head is accordingly increased. Because it will rise.

Now, the original image needs to be separated into three colors of R, G, and B. For this purpose, for example, the method shown in FIG. 6 or FIG. ), (B) and (c), the three charge storage media 21 _R , 2 ΐ _β , 21B -4B- An electrostatic latent image of a red image, a green image, and a blue image may be formed, or the electrostatic latent image may be formed using a color stripe filter by the method shown in FIG. It may be. If a color strip filter is used, the amount of misregistration between the color separation images is equal to the relative misregistration between the colors of the strip filter and the stripe filter. Depends on the positional accuracy of This means that if the strip filter is neat, no color shift will occur in principle. On the other hand, according to the method shown in FIG. 12, it is necessary to perform mechanical alignment with high accuracy.

 In the method using a color strip filter, if one spatially considers one color, the information in the filter portions of the other two colors is lost. On the other hand, in FIG. 12, a high-resolution color separation image can be obtained.

In order to take advantage of the high positional accuracy of the color strip filter method and obtain sufficient resolution, the R, G, and B color stripe pitch must be set to the required resolution. You only need to make it fine. For example, it is said that the resolution at which a halftone image of 175 line inches can be output is 500 line inches or more, so the size of one side of one pixel composed of R, G, and B colors is The length should be 50 m or less. In the case of reading color characters, a higher resolution is required than the image, and a 1200 to 2400-line Z-inch is required. Therefore, when reading color characters, the pitch of the power strip filter should be determined so that the pixel size is about 20 to 10 jcz m.c By this method, the position specified on the layout sheet is An electrostatic latent image of a document image of the specified size can be formed. Of course, if it is only necessary to form a full-sized electrostatic latent image without changing the position of the original image, as shown in FIG. Naturally, the R, G, and B electrostatic latent images can be formed adjacent to each other. The first 2 view, in the first 3 Figure 85, 86, 87, 88, 83 each represent a document, 85 _R, 85 _G, 85 _B, it respectively, the red image of the document 85, green image , Indicates a blue image.

 When exposing the image of each document, it is sufficient to expose only a predetermined position on the charge holding medium, and it is natural that the other parts should not be affected by the covering or the like. For this purpose, for example, exposure may be performed using a mask outside the exposure range. Also, it is desirable to form the photosensitive member electrode 22b and the charge holding medium electrode 21b in a strip shape, and to expose the photosensitive member electrode 22b and the charge holding medium electrode 21b so as to be substantially orthogonal to each other for exposure. A predetermined voltage may be applied only to the portion.

 When re-exposure is performed due to a shift in the exposure position or the like, the electrostatic latent image is temporarily erased using any of the above-described electrostatic latent image erasing methods, and the alignment is performed again to perform exposure. It is good.

After the formation of the R, G, and B electrostatic latent images of the image of the original document assigned to the relevant page is completed as described above, the potential reading method shown in FIG. 5 is then used. The electrostatic The latent image is read and taken into an appropriate image processing device as an electric signal. Then, image processing such as trimming, density adjustment, or color tone adjustment is performed as necessary, and finally supplied to a color scanner and output to a film. FIG. 14 shows an example of a configuration for that purpose.

First, the reading device 30 reads an electrostatic latent image recorded on the charge holding medium 21. In this method, the electrostatic latent image recorded on the charge holding medium 21 is read by the reading head 32 using the above-described electrostatic latent image reading method. The read analog data is amplified by the amplifier 33 and output to the image processing device 31. In the image processing device 91, first, the R, G, and B analog data supplied from the reading device 90 is converted into digital data of a predetermined number of bits by the digital conversion 34, and then trimming, Processing such as color conversion is performed. In FIG. 14, processing is performed in the order of trimming, color conversion, and blur correction. Trimming 35 is a process for extracting only the range specified by the layout sheet from the image data of each document.For example, displaying the captured image on a CRT or the like and specifying the range to be extracted Can be done with The color conversion 3B converts the data of R, G, B into data of C, M, Y, K. The data of C, Μ, Υ, Κ obtained by the color conversion 36 is Next, dust correction is performed by dust detection 97, and the data of C, M, Y, and K are converted into C ', Μ', Υ ', and デ ー タ' in consideration of ink smear. This makes it possible to prevent the print image from being smeared by ink smear. Smell The corrected image data is then subjected to halftone processing by halftone processing 98. The halftone process is performed by changing the size of the halftone dot according to the image density as shown in FIG. 15, for example, and when it is whitish, the halftone dot as shown in FIG. In the case of gray, halftone dots are 50% as shown in Fig. 15 (b), and when they are dark, halftone dots are as shown in Fig. 15 (c). In this manner, the pitch of the halftone dots is not changed, but the size of the halftone dots is changed according to the image density.

 For example, a method using a dot generator as shown in FIG. 16 may be used to form the halftone dots. The outline of this method is as follows. If one halftone dot is as shown in Fig. 16 (a), weighting is performed as shown in the figure, and the density level of the image corresponding to one halftone dot is calculated. If the value is 8 as shown in Fig. 16 (b), the weighting value is compared with the level 8 of the image.

16 Black as shown in Figure (c). In this way, halftone dots having a size corresponding to the density level can be formed.

 The halftone-processed image data is subjected to an exposure process by an exposure process 99 based on the result of the halftone process, supplied to a color scanner (not shown), and wound around an output drum. The exposed film is exposed.

FIG. 14 is a diagram showing only the flow of signal processing, and the device is configured to store digitally converted image data, image data obtained as a result of halftone dot processing, and the like. Storage devices, display devices such as color CRTs, keyboards and mice, etc. It is a matter of course that the device is provided with an input device and the like.

 As mentioned above, the plate-collecting system mainly for color images has been described. However, it is needless to say that application to a plate-collecting system for monochromatic images and monochromatic characters is also possible. Is obvious

 In the past, electrical or computer-based plate collection has mainly focused on color printers because it was extremely difficult to handle as many color separations as there are several colors without causing color shift. On the other hand, there was nothing that could not be done by hand on a monocle, and the cost was high. In other words, the cost performance of the electronic compiling system was poor for monocrocs.

 On the other hand, according to the present invention, the calculation processing required for the layout part which deteriorated the cost performance is not required, and the cost of the electronic plate collection system for the monocro is eliminated. It can greatly improve the performance.

 Industrial applicability

 The printing plate using the charge holding medium, the method for producing the same, and the plate collection system using the charge holding medium of the present invention are widely applied to the fields of plate making and plate printing.

Claims

The scope of the claims

1. A printing plate using a charge holding medium, which has an image portion formed of a charge holding layer and a toner layer on a conductive substrate.

 2. A predetermined voltage is applied between the photoreceptor and a charge holding medium composed of a conductive substrate and a charge holding layer, and a predetermined pattern is exposed from the photoreceptor side. A first step of forming an electrostatic latent image having a predetermined pattern, and a second step of performing toner development and fixing on the electrostatic latent image on the charge holding layer obtained in the first step And a third step of removing a portion of the charge holding layer other than the toner image obtained in the second step. A method for manufacturing a printing plate using a charge holding medium.

3. A photoreceptor and a charge holding medium are arranged facing each other, and a predetermined voltage is applied between the photoreceptor and the charge holding medium. An electrostatic latent image of the image of the print document is formed on the charge holding medium by exposing a predetermined position at a magnification and a direction, and the charge of the electrostatic latent image is read by a reading sensor. A plate collection system using a charge retention medium characterized by the following.