JPS62109062A - Printing original plate for electrophotoengraving - Google Patents

Abstract

PURPOSE:To obtain a printing original plate which has particularly high sensitivity and high printing resistance and permits easy photoengraving by providing an electric charge generating layer contg. an electric charge generating material on a conductive base and providing an electric charge transfer layer having the surface which can be made hydrophilic thereon. CONSTITUTION:The electric charge generating layer 2 contains the electric charge generating material. The charge generating material absorbs light and forms electrons and holes in the part subjected to the irradiation of light in the stage of image exposure after electrostatic charge in an image forming process by an electrophotographic method. Either of the electrons or the holes are passed to the conductive base 1 and the other to the charge transfer layer 3 by the electric field and pass therethrough by which the surface charge is neutralized and an electrostatic latent image is formed. The surface of the layer 3 to hold the electrostatic latent image is required to be high in resistance and hydrophobic to the extent of obviating the diffusion of the charge toward the plane direction. The holding of the electrostatic latent image is prohibited by the adsorption of water if said surface is hydrophilic. The electrostatic latent image is developed by the toner charged to the polarity reverse from the polarity of the surface charge and is fixed by which the toner image is formed on the layer 3.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a printing original plate for electrophotographic engraving, and more particularly to a printing original plate whose surface is made hydrophilic after forming a 1-ner image by electrophotography.

[Prior Art] As a planographic printing original plate, those using a photosensitive resin or a silver halide photosensitive material are known.

However, lithographic printing original plates using photosensitive resin have high printing durability, but have low sensitivity and cannot be used for so-called direct plate-making.Therefore, during plate-making, it is necessary to create a negative or positive from the original using a silver halide film. Therefore, it requires large-scale equipment and has drawbacks such as the time required for plate making. Further, although printing original plates using diffusion transfer development or hardening development methods of silver halide photosensitive materials can be directly plate-made, they have the disadvantages of low printing durability, high cost per sheet, and high cost.

As printing original plates for direct plate making using electrophotography, for example, Japanese Patent Publication Nos. 47-47610 and 48-
No. 40002, Special Publication No. 18325, Special Publication No. 18325, Special Publication No. 1971
Zinc oxide-resin dispersion systems are known as described in publications such as No. 15766 and Japanese Patent Publication No. 51-25761. After forming a toner image on this printing original plate by electrophotography, it is treated with an acidic aqueous solution containing, for example, a ferrocyan salt in order to make the non-image area hydrophilic. Printing plates made in this way suffer from peeling due to mechanical pressure applied during printing and penetration of dampening water into the photosensitive layer and conductive treatment layer, destroying the hydrophilic layer on the surface. The force is about 5,000-to, QOO pieces.

Further, although zinc oxide-resin dispersion printing original plates are dye-sensitized to have sensitivity in the visible light region, they still do not exhibit sensitivity sufficient for practical use in the long wavelength light region of 600 nm or more. Therefore, low-power and inexpensive He-Ne
The disadvantage is that exposure cannot be performed using a laser or semiconductor laser.

On the other hand, Special Publication No. 37-17162, Special Publication No. 38-775
No. 8, Special Publication No. 46-39405, Japanese Patent Publication No. 52-243
No. 7, JP-A-55-153948, JP-A-55-10
No. 5254, JP-A-56-107246, JP-A-56
-16125, JP-A-57-147656, JP-A-56-146145, JP-A-57-161 & 63, etc., for example, describe hydrophilic conductive supports such as grained aluminum plates. A layer consisting of an organic photoconductive compound and an alkali-soluble resin, a layer in which a charge-generating pigment such as a phthalocyanine pigment is dispersed in an alkali-soluble resin, or an electron-withdrawing substance or an electron-donating substance is added to this dispersed layer. A printing original plate for electrophotographic engraving provided with a sensitized layer is described. This type of printing original plate is made by forming a toner image on the photosensitive layer using an electrophotographic method, and then eluting and removing the photosensitive layer in the non-image area with an alkaline solution.It is a printing plate with high printing durability using direct platemaking. Although it has the advantage of being able to obtain
It has the disadvantage that a high output light source must be used.

Furthermore, Japanese Patent Publication No. 45-5606 describes a method of preparing a printing original plate having a hydrophilic treatment on the surface of a non-image area, which is easy to make by providing a specific resin layer on an ordinary electrophotographic photoreceptor. That is, a printing original plate is disclosed in which an electrophotographic photosensitive layer 1- is provided with a surface layer made of a vinyl ether-maleic anhydride copolymer and a hydrophobic resin compatible therewith. This layer is a layer that can be made hydrophilic by treating the non-image area with an alkali to open the acid anhydride ring portion with water after the toner image is formed.

However, the vinyl ether-maleic anhydride copolymer used here becomes water-soluble when the acid anhydride ring portion is ring-opened and made hydrophilic, so that high printing durability cannot be obtained. If the proportion of hydrophobic resin in the layer is increased in order to improve water resistance, the hydrophilicity of one surface will decrease, causing background stains on printed matter, so it has been difficult to achieve both hydrophilicity and water resistance.

[Purpose] The purpose of the present invention is to solve the above-mentioned problems of conventional printing plates for electrophotolithography, and to provide printing plates that are particularly sensitive, have high printing durability, and are easy to plate-make. .

[Structure] The printing original plate for electrophotolithography of the present invention has a charge generation layer containing a charge generation substance on a conductive support, and a charge transport layer on which one surface can be made hydrophilic. This is a characteristic feature.

Here, the charge transport layer whose surface can be made hydrophilic is advantageously a layer containing a charge transport substance, a reaction product of a resin having a cyclic a-anhydride structure, and a crosslinking agent. The "resin having an acid anhydride ring structure" includes a copolymer containing maleic anhydride as one copolymerization component (hereinafter referred to as "maleic anhydride copolymer"), and the "crosslinking agent" A typical example is a polyisocyanate compound.

Hereinafter, the present invention will be explained in more detail based on the accompanying drawings.

FIG. 1 is a sectional view showing the basic structure of the printing original plate according to the present invention, in which 1 represents a conductive support, 2 represents a charge generation layer, and 3 represents a charge transport layer whose surface can be made hydrophilic.

As mentioned above, the charge generation layer 2 contains a charge generation substance, and in the image forming process by electrophotography, the charge generation substance absorbs light in the areas irradiated with light during image exposure after charging. electrons and holes are generated. Due to the electric field, electrons and holes flow, one into the conductive support 1 and the other into the charge transport layer 3, through which they neutralize the surface charge and form an electrostatic latent image.

At this time, the surface of the layer 3 that holds the electrostatic latent image needs to be highly resistive and hydrophobic to the extent that the charge does not diffuse in the surface direction (if it is hydrophilic, the surface will become static due to the adsorption of water). (The latent image cannot be retained).

The electrostatic latent image is then developed with toner charged to the opposite polarity to the surface charge and fused to form a toner image on layer 3. Since printing is performed based on the difference between the lipophilicity (inkphilicity) of the toner image thus formed and the hydrophilicity of the non-image area, the surface of the layer 3 needs to be hydrophilic during printing.

In this way, in addition to transporting charges, layer 3 is required to have the function of changing from hydrophobicity during electrostatic latent image formation to hydrophilicity during printing. The reaction product between the resin and the crosslinking agent is originally hydrophobic and has sufficient resistance to maintain an electrostatic latent image, but when treated with an alkaline aqueous solution, the acid anhydride ring portion undergoes hydration and ring opening. It becomes hydrophilic and can be printed. Moreover, although it is hydrophilic, it is not water-soluble and has sufficient water resistance, so that high printing durability can be obtained.

Examples of charge generating substances used in the charge generating layer 2 of the present invention include zinc oxide, titanium oxide, zinc sulfide, selenium,
Examples include inorganic compounds such as selenium alloys, cadmium sulfide, cadmium selenide, and silicon, and organic compounds as shown in (1) to (14) below.

(1) Triphenylmethane pigments such as malachite green and crystal violet; methylene blue,
Thiazine dyes such as methylene green; 7-strazone dyes such as Astrazone Orange R, Astrazone Yellow 3GL, and Astrazone Red 6B; Cyanine dyes such as Eisen Astrafuroxin FF; Xanthine dyes such as Rhodamine B; 2,6-diphenyl- 4,-(N,
Cationic dyes such as pyrylium dyes such as N-dimethylaminophenyl) thiapyrylium verchlorate, benzopyrylium salts.

(2) Perylene pigments such as perylene anhydride and perylene imide.

(3) Indigo pigment.

(4) Quinacridone pigment.

(5) Polycyclic quinones such as anthraquinones, pyrenequinones, anthoanthros, and flavanthrones.

(6) Bisbenzimidazole pigment.

(7) Square methine pigment.

(8) Indathlon pigment.

(9) Phthalocyanine pigments such as metal phthalocyanines such as copper phthalocyanine and metal-free phthalocyanines.

(io) A charge transfer complex consisting of an electron donating substance such as poly-N-vinylcarbazole and an electron accepting substance such as 2,4,7-trinitrofluorenone.

(11) A eutectic complex formed from a pyrylium salt dye and polycarbonate 1 to resin.

(12) Barbyric acid derivative or thiobarbital acid derivative.

(13) Azo pigments such as monoazo pigments, disazo pigments and triazo pigments. Examples of monoazo pigments include monoazo pigments with central skeletons such as anthraquinone and N-phenylcarbazole, and examples of disazo pigments include benzidine pigments such as Diane Blue and Chlordiane Blue, or N-ethylcarbazole, stilbene, and disazo pigments. stilbenzene, naphthalene, fluorenone,
Fluorene, anthraquinone, 2,5-diphenyl-1
, 3,4-oxadiazole, dibenzothiophene, dibenzothiophene dioxide, acridone, phenanthrenequinone, etc., and trisazo pigments include, for example, 1-diphenylamino or N-phenylcarbazole. There are trisazo pigments that serve as the skeleton.

As the resin having a cyclic acid anhydride structure used in the hydrophilic charge transport layer 3, a copolymer containing maleic anhydride as one copolymerization component is suitable as described above.
More specifically, for example, methyl vinyl ether, ethyl vinyl ether, 2-chlorovinylethyl ether,
Propyl vinyl ether, isobutyl vinyl ether,
Copolymers of lower alkyl vinyl ethers such as 2-methoxyethyl vinyl ether and maleic anhydride, copolymers of styrene and maleic anhydride, copolymers of ethylene and maleic anhydride, and copolymers of vinyl acetate and maleic anhydride. There are copolymers, etc. Further, copolymers of these with a part of the cyclic structure opened can also be used.

A typical example of the crosslinking agent is a polyisocyanate compound. Polyisocyanate compounds include toluene-2,4-diisocyanate and toluene-2,6-diisocyanate.
Diisocyanate, naphthylene-1,5-diisocyanate, 3,3'-dimethylbiphenyl-4,4'-diisocyanate, triphenylmethane-4,4', 4'
- Aromatic polyisocyanates such as triisocyanate, tris(p-isocyanate phenyl) thiophosphite, polymethylene polyphenyl isocyanate, xylylene diisocyanate, or aliphatic polyisocyanates such as hexamethylene diisocyanate, inphorone diisocyanate, or dimers thereof body, dimer, etc.

The charge transport layer 3 contains a charge transport substance.

Charge transporting substances include hole transporting substances and electron transporting substances. Examples of hole transporting substances include 2,5-bis(4-diethylaminophenyl)-1,3°4-oxadiazole, 2,5- Bis(4-(4-diethylaminostyryl)
phenyl)-1,3゜4-oxadiazole, 2-(9
-Ethylcarbazolyl-3-)-5-(4-diethylaminophenyl)-1,3,4-oxadiazole and other oxadiazole compounds; 2-vinyl-4-(2-chlorophenyl)-5- Oxazole compounds such as (4-diethylamino)oxazole, 2-(4-diethylaminophenyl)-4-phenyloxazole; 1-phenyl-3-(4-diethylaminostyryl)-5-(4-
diethylaminophenyl)pyrazoline, 1-phenyl-
Pyrazoline compounds such as 3-(4-dimethylaminostyryl)-5-(4-dimethylaminophenyl)pyrazoline; 2゜2'-dimethyl-4,4'-bis(diethylamino)triphenylmethane, 1,1-bis Diphenylmethane compounds such as (4-dibenzylaminophenyl)propane and tris(4-diethylaminophenyl)methane; 9-(4-dimethylaminobenzylidene)fluorene, 3-(9-fluorene compound)-9-nitylcarbazole, etc. Fluorene compound; 9-(4-diethylaminostyryl)anthracene, 9-bromo-1
Styryl anthracene compounds such as 0-(4-diethylaminostyryl) anthracene; distyrylbenzene compounds such as 1,2-bis(4-diethylaminostyryl)benzene and 1,2-bis(2°4-dimethoxystyryl)benzene; 9 -Ethylcarbazole-3-aldehyde 1-methyl-1-phenylhydrazone, 9-ethylcarbazole-3-aldehyde 1-benzyl-1-phenylhydrazone, 4-diethylaminobenzaldehyde 1
, 1-diphenylhydrazone, 2,4-dimethoxybenzaldehyde 1-benzyl-1-phenylhydrazone,
4-diphenylaminobenzaldehyde 1-methyl-1
-Hydrazone compounds such as phenylhydrazone; Stilbene compounds such as 4-diphenylaminostilbene, 4-dibenzylaminostilbene, and 4-ditolyllaminostilbene; 1-(4-diphenylaminostyryl)naphthalene, 1-(4-dibenzyl) Styrylnaphthalene compounds such as (aminostyryl) naphthalene; α-phenylstilbene compounds such as 4'-diphenylamino-α-phenylstilbene, 4'-methylphenylamino-α-phenylstilbene; 3-styryl-9-ethylcarbazole, 3 - (4-diethylamino)styryl-9
- A styrylcarbazole compound such as ethylcarbazole; or a polymer compound such as poly-N-vinylcarbazole is used.

Examples of electron transport substances include chloranil, bromoanil, tetracyanoethylene, tetracyanoquinodimethane, 2,4.7-dolinitro-9-fluorenone, 2,
4,5.7-tetranitro-9-fluorenone, 2,4
, 5.7-tetranitroxanthone, 2,4.8-trinidrothioxanthone, 2,6.8-trinitro-4H
-indeno(1,2-b)thiophen-4-one, 1.
Examples include 3,7-trinitrodibenzothiophene-5°5-dioxide.

As the conductive support 1, for example, a plastic film having a conductive surface such as an aluminum vapor-deposited film;
Water-resistant, solvent-resistant and conductive treated paper; aluminum plate, zinc, copper plate.

A metal plate such as a stainless steel plate is used.

In order to produce the printing original plate for electrophotographic engraving of the present invention, first, the charge generating substance described above is mixed with a binder resin such as polyester resin, polycarbonate resin, acrylic resin,
Polystyrene resin, polyamide resin, polyvinyl butyral resin, vinylidene chloride resin, etc. are added to an organic solvent (tetrahydrofuran, dioxane, dimethylformamide, acetone, methyl ethyl ketone, ethylene glycol heptanoethyl ether, ethyl acetate, cyclohexanone, etc.), and A coating solution uniformly dispersed by a dispersing means such as a sonic disperser is applied onto the conductive support 1 and dried to form the charge generation layer 2.

Next, a coating solution prepared by adding a crosslinking agent such as a polyisocyanate compound to a solution in which a charge transport substance and a maleic anhydride copolymer are dissolved in the same organic solvent as above is applied onto the charge generation layer 2. This is carried out by drying, and further performing a heat treatment to cause a crosslinking reaction to form a charge transport layer 3 that can be made into a parent material.

The temperature and time of this heat treatment vary depending on the combination of maleic anhydride copolymer and polyisocyanate compound used, but can be selected in the range of approximately 80 to 200°C and several minutes to several hours. Further, in order to promote the crosslinking reaction between the maleic anhydride copolymer and the polyisocyanate compound, examples of catalysts include dibutyltin dilaurate, dibutyltin acetate, and lead 2-ethylhexanoate.

Titanium tetrabutoxide, tin octoate, dibutyltin (2-ethylhexoate), potassium oleate,
Metal compounds such as antimony trichloride, or
Amic acids such as triethylamine, 1 to ethylecidiamine, etc. can be added as appropriate.

The hydrophilic charge transport layer 3 is mainly composed of a maleic anhydride copolymer crosslinked with a charge transport substance and a polyisocyanate compound, but in order to improve the strength of the layer, other resins such as polyester resin may be used. , polyamide resin, polycarbonate resin, acrylic resin, polystyrene resin,
Vinyl acetal resin or vinyl acetate resin can be added. However, in this case, the proportion of these resins contained in the entire layer is preferably 50% by weight or less. If the ratio is higher than this, the rate of hydrophilization is slow and the hydrophilicity becomes insufficient in the hydrophilic treatment of the surface of the non-image area performed after one image is formed, resulting in background stains on the printed matter.

The proportion of the charge transport substance in the hydrophilic charge transport layer 3 is:
Preferably 10 to 95% by weight, more preferably 30 to 9% by weight
It is 0% by weight. Below this range, sensitivity is low, and above this range, printing durability is reduced.

Further, the thickness of the charge transport layer 3 is preferably 3 to 50 μm, and more preferably 5 to 20 μm. Below this range, charging will not be sufficient, and above this range, the residual potential will be high and cause staining of the background.

The proportion of the charge generating substance in the charge generating layer 2 is 10 to 80% by weight, preferably 20 to 70% by weight. Below this range, sensitivity is low, and above this range, the mechanical strength of the layer decreases and is not practical. The n-thickness of the charge generation layer 2 is preferably 0.05 to 5 μm, more preferably 0.1 to 2 μm.
It is. Below this range, the sensitivity is low, and above this range, the residual potential is high and causes background stains.

Plate making using the printing original plate for electrophotographic platemaking of the present invention first follows the usual electrophotographic method, and is uniformly charged in a dark place using a corona charger or the like, and then charged using a tungsten lamp, halogen lamp, xenon lamp, or fluorescent lamp. An electrostatic latent image is formed by reflective image exposure using a light source such as a lamp, contact image exposure through a transparent positive film, or scanning exposure using a laser beam such as a He-Ne laser, an argon laser, or a semiconductor laser.

This electrostatic latent image is developed with toner and fixed by heating to obtain a toner image 4 on the electrophotographic photosensitive layer (FIG. 2).

Next, when the printing original plate on which this toner image has been formed is immersed in an alkaline parent wood treatment liquid, the surface of the non-image area (the surface of the charge transport layer 3) that is not masked by the toner image is made hydrophilic, resulting in good printing. A plate is obtained (Figure 3). In FIG. 3, numeral 5 represents a hydrophilized portion.

The parent tree treatment solution used here is, for example, an alkaline aqueous solution of an inorganic salt such as sodium silicate, sodium phosphate, sodium hydroxide, or sodium carbonate, or an alkaline aqueous solution containing organic amines such as triethanolamine or ethylenediamine, or an alkaline aqueous solution containing ethanol, A solution containing an organic solvent such as benzyl alcohol, ethylene glycol, or glycerin or a surfactant is used.

The time required for hydrophilization varies depending on the formulation of the charge transport layer 3, the concentration of the parent wood treatment liquid, etc., but it can be carried out in about 10 to 120 seconds by selecting appropriate conditions.

Since the printing original plate of the present invention is subjected to hydrophilic treatment only on the non-image areas, it is preferable that the toner component contains a resin component having resistivity in the hydrophilic treatment liquid.

This resin component may be any one as long as it is insoluble in the T11 exudate.For example, acrylic resin using methacrylic acid, methacrylic ester, vinyl acetate resin, etc.
Copolymers of vinyl acetate and ethylene or vinyl chloride, vinyl chloride resins, vinylidene chloride resins, vinyl acetal resins such as polyvinyl butyral, polystyrene, copolymers of styrene and butadiene, methacrylate esters, etc., polyethylene, polypropylene, Its chloride, polycarbonate.

polyester resin, polyamide resin, phenolic resin,
These include xylene resin, alkyd resin, wax, polyolefin, and wax.

After completing the plate-making process described above, the printing original plate of the present invention becomes a printing plate having an image area covered with lipophilic toner and a surface of a non-image area that has been made highly hydrophilic. It adheres only to the surface of the paper, resulting in good printed matter with no background stains.

EXAMPLES Below, the present invention will be explained in more detail with reference to Examples. In addition, all "parts" in the examples represent parts by weight.

Example 1 1 part of a disazo pigment (charge generating substance) represented by the following structural formula (1), 19 parts of tetrahydrofuran, and polyvinyl butyral resin (Denka Butyral 54000-1:
A mixture consisting of 6 parts of a 5% by weight tetrahydrofuran solution manufactured by Denki Kagakusha Co., Ltd. ($1) was sufficiently ground in a ball mill.

The mixture was then taken out and diluted by adding 104 parts of tetrahydrofuran while stirring slowly. This solution was coated on a polyester film (conductive support) with a thickness of about 100 μm on which aluminum was vapor-deposited, dried at 80°C for 5 minutes, and coated on the charge generation layer of the electrode to a thickness of about 0.5 μm. Charge transport substance 10 represented by the following structural formula (II)
Part, methyl vinyl ether-maleic anhydride copolymer (
A solution consisting of 10 parts (manufactured by Aldrich Chemical Company, Inc.), 1 part of toluene-2,4-diisocyanate and 80 parts of tetrahydrofuran was applied and heated at 80°C for 2 minutes.
After drying at 105° C. for 5 minutes, heat treatment was performed at 150° C. for 30 minutes to form a hydrophilic charge transport layer having a thickness of about 10 μm.

The printing original plate for electrophotographic engraving produced in this way is charged to a surface potential of approximately -800 volts by corona discharge in a dark place, and then imagewise exposed through a lens system using a halogen lamp to form an electrostatic latent image. After that, it was developed with toner for copying machines and fixed by heating to form a toner image.

Next, in order to make the non-image area hydrophilic, it was immersed in a 3% by weight aqueous sodium metasilicate solution for 60 seconds.

The lithographic printing plate made in this way was mounted on an offset printing machine and printed according to the conventional method.

We were able to print over 3,000 good quality prints.

Example 2 In place of the charge transport substance (It) in Example 1, 2.
4. The same procedure as in Example 1 was carried out except that 7-h linitrofluorenone was used and positively charged in the plate-making process. When printing was performed using the obtained printing plate, more than 3,000 good prints were produced. I was able to print it.

Example 3 1 part of a disazo pigment (charge generating substance) represented by the following structural formula (III), 0.33 part of polyester resin (manufactured by Toyobo Co., Ltd.: Vylon 200), and 60 parts of tetrahydrofuran
The mixture consisting of 1.5 parts was thoroughly ground in a ball mill. This dispersion was applied onto a polyester film on which aluminum was vapor-deposited on one surface, and dried at 80° C. for 5 minutes to form a charge generation layer having a thickness of about 0.5 μl.

(Left below) On this charge generation layer, 10 parts of a charge transporting substance represented by the following structural formula (rV), 10 parts of methyl vinyl ether-maleic anhydride copolymer, 1 part of toluene-2,4-diisocyanate, 80 parts of tetrahydrofuran After drying at 80° C. for 2 minutes and at 105° C. for 5 minutes, heat treatment was performed at 150° C. for 30 minutes to form a hydrophilic charge transport layer having a thickness of about 10 μm.

When the printing original plate for electrophotographic engraving thus produced was processed and plate-made in the same manner as in Example 1, and the obtained printing plate was used for printing, more than 3,000 good-quality printed materials were printed.

Example 4 1 part of trisazo pigment (charge generating substance) represented by the following structural formula (V), 0.33 part of polyvinyl butyral resin (
A mixture consisting of 12 parts of cyclohexanone (same as in Example 1) and 12 parts of cyclohexanone was sufficiently ground in a ball mill, and then 31 parts of cyclohexanone was added to this liquid with stirring to dilute it. This liquid was applied onto a polyester film on which aluminum was vapor-deposited, and dried at 120° C. for 5 minutes to form a charge generation layer with a thickness of about 0.5 μm. Next, the same charge transport layer as in Example 3 was formed on this charge generation layer.

The electrophotographic printing original plate thus prepared was processed and plate-made in the same manner as in Example 2, and when printing was performed using the obtained printing plate, a good mark was obtained.

I was able to print over 3,000 pieces.

[Effects] The printing original plate of the present invention has particularly high sensitivity compared to conventionally known printing original plates, and by selecting a charge-generating substance, direct plate making is possible with various light sources such as a He-Ne laser and a semiconductor laser.

[Brief explanation of drawings]

FIG. 1 is an enlarged sectional view of the electrophotographic printing plate of the present invention. Also, Figures 2 and 3 are for explaining the plate-making process, and Figure 2 shows the state after toner image formation,
FIG. 3 shows the state after parent tree processing. 1... Conductive support 2... Charge generation layer 3... Charge transport layer 4... Toner image 5... Hydrophilized partial patent applicant Rico Co., Ltd. - Agent Patent attorney Tsuki Shigeru Mura and others 1 each city 1 drawing gate 2 reprimand 3 sides procedural amendment April 23, 1985 Patent Application No. 248104 filed in 1985 2, name of invention printing original plate for electrophotographic engraving 3, person making amendment case and Relationship Patent applicant 1-3-6 Nakamagome, Ota-ku, Tokyo (674) Ricoh Co., Ltd. Representative Hama 1) Hiro 4, Agent 5, Detailed explanation of the invention r of the specification subject to amendment J Column 6, "Acid anhydride cyclic structure" in page 6, line 6 and page 7, last line of the specification of amendment is corrected to "cyclic acid anhydride structure J."

Claims (1)

[Claims] 1. An electrophotographic plate comprising a charge generation layer containing a charge generation substance provided on a conductive support, and a charge transport layer whose surface can be made hydrophilic provided thereon. Original printing plate. 2. The electrophotography according to claim 1, wherein the charge transport layer whose surface can be made hydrophilic contains a charge transport substance, a reaction product of a resin having a cyclic acid anhydride structure, and a crosslinking agent. Original printing plate for plate making.