JPS61217293A - Plate blank for electronic photo plate-making process - Google Patents

Abstract

PURPOSE:To obtain a plate blank high in sensitivity and durability in printing and easy to manufacture, by a method wherein an electric charge feeding layer is provided on a conductive base, and an electric charge generating layer comprising an electric charge generating substance and a reaction product of a specified resin with a crosslinking agent is provided thereon. CONSTITUTION:The electric charge feeding layer 2 comprising an electric charge feeding substance as a main constituent is provided on the conductive base 1, and the electric charge generating layer 3 which comprises an electric charge generating substance and a reaction product of a crosslinking agent with a resin having an acid anhydride ring structure and the surface of which can be made hydrophilic is provided thereon. The layer 3 is required to have not only an electric charge generating function but also a function of being changed from a hydrophobic state at the time of forming an electrostatic latent image to a hydrophilic state at the time of printing. The reaction product of a crosslinking agent and a resin having an aicd anhydride ring structure, per se, is hydrophobic and has sufficient resistance for holding the latent image, but when it is treated when an alkaline aqueous solution, the acid anhydride ring part is opened by water to provide hydrophilic nature, which enables printing. Since the surface of the layer 3 becomes hydrophic but not water-soluble and has sufficient water resistance, durability in printing can be obtained.

Description

[Detailed description of the invention] Technical field The present invention relates to a printing original plate for electrophotographic engraving.

More specifically, the present invention relates to a printing original plate whose surface is made hydrophilic after forming a toner image by electrophotography.

BACKGROUND ART Conventionally, as planographic printing original plates, those using photosensitive resins or silver halide photosensitive materials have been known.

[2] However, although lithographic printing plates using photosensitive resin have high printing durability, they have low sensitivity and cannot be used for so-called direct plate making, and it is difficult to create a negative or positive from a silver halide film from an original. However, there are drawbacks such as the need for large-scale equipment and the time required for plate making.

Further, printing plates using diffusion transfer development or curing development of silver halide photosensitive materials can be used as direct one-plate plates, but they have the drawbacks of low printing durability and high cost per sheet.

Examples of printing plates for direct plate making using electrophotography include JP-B No. 47-47610 and JP-B No. 48-40.
002, Special Publication No. 48-18325, Special Publication No. 51-152
66, Japanese Patent Publication No. 5]-25761, a zinc oxide-resin dispersion printing plate is known. After forming a toner image on this printing 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. The printing plates made in this way are free from the mechanical pressure applied during printing and the photosensitive layer of the dampening solution.
Penetration into the conductive treatment layer causes peeling and destroys the hydrophilic layer on the surface, so its printing durability is 5,000 to 10
,000 sheets.

In addition, zinc oxide/resin dispersion printing plates are dye sensitized in order to have sensitivity in the visible light region, but even so, they 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-N
The drawback is that exposure cannot be performed using an e-laser or a semiconductor laser.

On the other hand, Special Publick No. 37-17162. Tokuko Sho 38-7758
゜Special Publication Showa 46-39405. JP 52-2437%, JP 56-107246, JP 55-105254.
JP-A-55-153948, JP-A-56-16125,
JP-A-57-147656, JP-A-56-146145
゜% Publication No. 57-161863 describes, for example, a layer consisting of an organic photoconductive compound and an alkali-soluble resin on a hydrophilic conductive support such as a grained aluminum plate, or a phthalocyanine-based layer. A printing original plate for electrophotographic engraving is shown, which has a layer in which a charge-generating pigment such as a pigment is dispersed in an alkali-soluble resin, or a layer sensitized by adding an electron-withdrawing substance or an electron-donating substance to this dispersed layer. has been done. 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. Although it has the advantage that a printing plate can be obtained, it has low sensitivity as a photoreceptor for electrophotography, resulting in a slow plate-making speed and the disadvantage that a high-output light source must be used.

Further, Japanese Patent Publication No. 5606/1989 discloses a method for preparing a printing plate of a hydrophilic treatment type 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 plate is disclosed in which a surface layer comprising a vinyl ether-maleic anhydride copolymer and a hydrophobic resin compatible therewith is provided on an electrophotographic photosensitive layer. 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 part opens and becomes hydrophilic, so high printing durability could not be obtained. .

If the proportion of hydrophobic resin in the layer is increased in order to improve water resistance, the hydrophilicity of the surface will decrease and cause staining of the printed material, so it has been difficult to achieve both water resistance and water resistance. , Object The purpose of the present invention is to solve the above-mentioned problems of conventional printing plates for electrophotolithography, and to provide a printing plate that has particularly high sensitivity, high printing durability, and is easy to plate. Structure: The printing original plate for electrophotographic engraving of the present invention has a charge transporting layer containing a charge transporting substance as a main component on a conductive support, and a charge-transporting layer containing a charge-generating substance and a resin having an acid anhydride ring structure and cross-linking thereon. It is characterized by providing a charge generation layer whose surface is made of a reaction product with an agent and whose surface can be made hydrophilic.

Here, as the resin having an acid anhydride ring structure, a copolymer containing maleic anhydride as one copolymerization component (hereinafter abbreviated as maleic anhydride copolymer) is typical, and as a crosslinking agent, a polyisocyanate compound is typical. It can be given as something.

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

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

The charge generation layer 3 contains a charge generation substance as described above, and in the image forming process by electrophotography,
At the time of image exposure after charging, the charge-generating material absorbs light in the portion irradiated with light, and electrons and holes are generated.

The m-sons and holes are injected by the electric field into the charge transport layer 2, through which they flow to the conductive support.

On the other hand, an electrostatic latent image is formed by neutralizing the charge on the surface. At this time, the surface of the layer 3 that holds the electrostatic latent image needs to have high resistance and be hydrophobic to the extent that charge diffusion in the surface direction does not occur (if it is hydrophilic, water will be adsorbed, The electrostatic latent image is then developed and fixed by a toner charged to the opposite polarity to the surface weight, and the electrostatic latent image is fixed.
A toner image is formed thereon. Printing is performed based on the difference between the lipophilicity (inkphilicity) of the toner image formed in this way and the hydrophilicity of the non-image area, so the surfaces 1-3 need to be hydrophilic during printing. .

In this way, layer 3 has an acid anhydride ring structure used in layer 3 in the present invention, which is required to have the function of changing from hydrophobicity during electrostatic latent image formation to hydrophilicity during printing, in addition to generating charge. 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 part is hydrated and opened. 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 the charge generation substance used in the hydrophilic charge generation layer 3 of the present invention include inorganic compounds such as zinc oxide, titanium oxide, zinc sulfide, selenium, selenium alloys, cadmium sulfide, cadmium selenide, and silicon; , and organic compounds as shown in (1) to (141) below.

(1) Triphenylmethane dyes such as malachite green and crystal violet, thiazine dyes such as methylene sol and methylene green, astrazone dyes such as Astrazone Yellow 3GL, Astrazone L/T'6B, and crampons. Cyanine dyes such as Astrafuroxin FF, xanthine dyes such as Rhodamine B, 2,6-diphenyl-4-(
cationic dyes such as biryllium dyes such as N,N-dimethylaminophenyl)thiavirillium nozo-chlorate, benzopyrylium salts, (2) herylenic anhydride and perylene f1! ``Perylene pigments such as imide.

(3) Indigo pigment, (4) Quinacridone normal phase.

(5) polycyclic quinones such as anthraquinones, pyrenequinones, anthoanthros and furanocentrons; (6) bisbenzimidazole pigments.

(7) Square methine pigment.

(8) induthrone pigments; (9) phthalocyanine pigments such as metal phthalocyanines and metal-free phthalocyanines; A charge-transfer complex consisting of an electron-accepting substance such as fluorenone.

α-throwing Eutectic complex formed from biryllium ring dye and polycarbonate resin, 04 Nororbituric acid derivatives or thio-norbituric acid derivatives, (11 Azo pigments such as monoazo pigments, disazo pigments and trisazo pigments. As monoazo pigments) For example, monoazo pigments having a central skeleton such as anthraquinone or N-phenylcarbazole are used; examples of disazo pigments include benzidine pigments such as Diane Blue and Chlordiane Blue, or N-ethylcarnozole, stilbene, and distilbenzene. , naphthalene, fluorenone,
Fluorene, anthraquinone, 2,5-diphenyl-1
, 3゜Disazo pigments having a central skeleton of 4-oxadiazole, dibenzothiophene, dipenzothiophene dioxite, acridone, phenanthrenequinone, etc. are used as trisazo pigments, such as triphenylatine or N-phenylcarbazole. There are trisazo pigments that serve as the central skeleton.

As the resin having an acid anhydride ring structure used in the hydrophilic charge generation layer 3, a copolymer containing maleic anhydride as one copolymer component is suitable as described above, but more specifically, Methyl vinyl ether, ethyl vinyl ether, 2-chlorovinylethyl ether,
Broll vinyl ether, isobutyl vinyl ether,
2-,%) Copolymers of lower alkyl vinyl ethers such as xyethyl vinyl ether and maleic anhydride, copolymers of styrene and maleic anhydride, copolymers of ethylene and maleic anhydride, copolymers of vinyl acetate and maleic anhydride. These maleic anhydride copolymers with some of the acid anhydride rings open can also be used.

Further, as the crosslinking agent, a polyisocyanate compound is preferable, but examples of the polyisocyanate compound include toluene-2,4-diisocyanate, toluene-2,4-diisocyanate, and toluene-2,4-diisocyanate.
2,6-diisocyanate, naphthylene-1,5-diisocyanate, 313'-dimethylpiphenyl-4,4
'-diisocyanate, triphenylmethane-4,4'
.

Aromatic polyisocyanates such as 4″-triisocyanate, tris(p-isocyanate phenyl) thiophosphite, polymethylene polyphenyl isocyanate, and xylylene diisocyanate, or aliphatic polyisocyanates such as hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, and isophorone diisocyanate. Examples include polyisocyanates, dimers thereof, and sancheng forms.

The charge transport layer 2 contains a charge transport substance as a main component, and is formed using a binding resin if necessary.

Charge transporting substances include hole transporting substances and electron transporting substances.
diethylaminophenyl)-1,3,4-oxadiazole, 2,5-bis(4-(4-diethylaminostyryl)phenyl-1,3,4-oxadiazole, 2-
Oxadiazole compounds such as (9-ethylcarnozolyl-3-)-5-(4-diethylaminophenyl)-1,3,4-oxacyapur, 2-vinyl-4-(
2-chlorophenyl)-5=(4-diethylamino)oxazole, 2-C4-diethylaminophenyl)-4
-Oxazole compounds such as phenyloxazole, ]
-Phenyl-3-(4-jethylaminostiri/I/
) -5-(4-diethylaminophenyl)pyrazoline, ]-phenyl-3-(4-dimethylaminostyryl)
-Pyrazoline compounds such as 5-(4-dimethylaminophenyl)pyrazoline, 2,2'-dimethyl-4,4'-
Bis(diethylamino)triphenylmethane, ],
]-Diphenylmethane compounds such as bis(4-dipendylaminophenyl)pronξ and tris(4-diethylaminophenyl)methane% 9-(4-dimethylaminobenzylidene)fluorene, 3-(9-fluorene compounds)- Fluorene compounds such as 9-ethyl carnocesol, styryl anthracene compounds such as 9-(4-diethylaminostyryl) anthracene, 9-chromium-10-(4-diethylaminostyryl) anthracene, 1.2-bis(4-diethylaminostyryl) ) benzene, distyryl hardenzene compounds such as 1,2-bis(2,4-dimethoxystyryl)benzene, 9-ethylcarnozole-3-aldehyde)J-methyl-1-phenylhydrazone, 9-ethylcarnozole-3- Aldehyde]-benzyl-1-phenylhydrazone, 4-diethylamino 4-dzaldehyde 'f'J, 1-diphenylhydrazone, 2,4-dimethoxybenzaldehyde 1
-hydrazone compounds such as benzyl-1-phenylhydrazone, 4-diethylamino-4-nuzaldehyde)'1-methyl-1-phenylhydrazone, stilbenes such as 4-diphenylaminostilbene, 4-dibenzylaminostilpene, and 4-ditolylaminostilbene Stilbene compounds such as 1-(4-diphenylaminostyryl)naphthalene, styrylnaphthalene compounds such as ]-(4-dibenzylaminostyryl)naphthalene, 4'-diphenylamino-a-phenylstyrene% 4'-methyl α-Phenylstilbene compounds such as phenylamino-α-phenylstilben, 3-styryl-9-ethylcarnozole, 3-(4-diethylamino)styryl-
A styryl carnosol compound such as 9-ethylcarnosol or a polymer compound such as poly-N-vinyl carnocesol is used.

Examples of electron transport substances include chloranyl,
Romuanil, tetracyanoethylene, tetracyanoquinone dimethane, 2.4.7-dolinitro-9-fluorenone, 2.4.5.7-tetranitro-9-fluorenone, 2.4.5.7-ketone nitroxanthone, 2 .4.
8-trinidrothioxanthone, 2.6.8-)dinitro-4H-indeno[1,2=b]thiophene-4
-on, 1.3. 'y-trinitrodibenzothiophene-5,5-dioxide etc. Also, examples of the binding resin include polyester resin, polycarbonate resin, acrylic resin, polystyrene, polyamide, polyacrylamide, polyvinyl acetal, polyvinyl butyral. etc.

As the conductive support, for example, a plastic film having a conductive surface such as an aluminum vapor-deposited film;
6. To produce the printing plate for electrophotographic engraving of the present invention, a metal plate such as a paper Nialuminum plate, zinc plate, copper plate, or stainless steel plate, which has been treated with water resistance, solvent resistance treatment, and conductivity treatment, is used.
First, the charge transport substance and the binding resin are dissolved in a suitable organic solvent such as tetrahydrofuran, dioxane, dimethylformamide, acetone, methyl ethyl ketone,
Ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethyl acetate, butyl acetate.

A solution dissolved in toluene, halogenated hydrocarbon, etc. is applied onto a conductive support and dried to provide a charge transport layer 2.

Next, a charge generating substance is added to a solution of the maleic anhydride copolymer dissolved in the same organic solvent as above, and the mixture is uniformly dispersed using a dispersion means such as a Zeel mill or an ultrasonic dispersion machine.
A coating solution containing a polyisocyanate compound is applied onto the charge transport layer, dried, and further heat-treated to cause a crosslinking reaction to form the charge generation layer 3.

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. In order to promote the crosslinking reaction between the copolymer and the polyincyanate compound, for example, dibutyltin dilaurate, dizotyltin acetate, lead 2-ethylhexanoate, titanium tetrabutoxide, tin octoate, dibutyltin (2-
Metal compounds such as ethylhexoate), potassium oleate, and antimony trichloride, or amines such as triethylamine and triethylenediamine can be added in appropriate amounts.

The hydrophilic charge generation layer 3 is mainly composed of a maleic anhydride copolymer crosslinked with a charge generation substance and a polyisocyanate compound, but in order to improve the strength of the layer, other resins such as polyester resin may be used. Monthly, polyamide resin
In addition, polycarbonate resin, acrylic resin, polystyrene resin, vinyl acetal resin, vinyl acetate resin, etc. 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 it exceeds this range, the speed of hydrophilic treatment of the surface of the non-image area after image formation becomes slow and the water resistance becomes insufficient, resulting in background stains on printed matter.

The proportion of the charge generating substance in the hydrophilic charge generating layer 3 is as follows:
Preferably 10 to 80 weights, even more preferably 20 to 70 weights! [is. Below this range, sensitivity is low, and above this range, printing durability is reduced. Further, the thickness of the charge generation layer 3 is preferably 0.05 to 5 μm, more preferably 0.1 to 2 μm. Below this range, the sensitivity is still low, and above this range, the residual potential becomes high and causes staining of the background.

The ratio of the material transported in the transport layer 2 in the transport layer 2 is 10 to 95.
If the weight is less than this range, the friction sensitivity will be low, and if it is more than this, the mechanical strength of the layer will decrease and it will not be practical. Further, the thickness of the charge transport layer 2 is preferably 3 to 50 μm, more preferably 5 μm.
Below this range, which is 20 μm, sufficient charging will not be achieved, and above this range, the residual potential will be high and cause staining of the background.

The plate making of the printing original plate for electrophotographic platemaking of the present invention is first carried out in accordance with the usual electrophotographic method, and is uniformly charged in a dark place using a corona zone evaporator, etc., and then heated using a tungsten lamp, halogen lamp, xenon lamp, or fluorescent lamp. An electrostatic latent image is formed by reflection image exposure using a light source such as a transparent film, contact image blue light through a transparent positive film, or scanning exposure using a laser light such as a He-Ne laser, an argon laser, or a semiconductor laser. ilf, the latent image is developed with toner and fixed by heating to obtain a toner image 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 hydrophilic treatment liquid, the surface of the non-image area that is not masked by the toner image (the surface of the charge generation layer 3) is made hydrophilic, resulting in a good printing plate. is obtained. (Figure 3) The hydrophilic treatment liquid used here is, for example, an alkaline aqueous solution of inorganic salts such as titrium silicate, sodium phosphate, sodium hydroxide, and sodium carbonate, or an alkaline aqueous solution containing organic amines such as triethanolamine and ethylenediamine. A solution prepared by adding an organic solvent such as ethanol, benzyl alcohol, ethylene glycol, or glycerin or a surfactant to these is used.

The time required for hydrophilization varies depending on the formulation of the charge generation layer 3 and the concentration of the hydrophilic treatment liquid, but it can be carried out in about 10 to 30 seconds by selecting appropriate conditions.

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

This resin component may be anything as long as it is insoluble in the eluate2.For example, acrylic resin using methacrylic acid, methacrylic acid ester, etc., vinyl acetate resin, copolymer of vinyl acetate and ethylene or vinyl chloride, etc. , vinyl chloride resin, vinylidene chloride resin, vinyl acetal resin such as polyvinyl butyral, copolymers such as styrene, styrene and butadiene, methacrylic acid ester, polyethylene, polypropylene and their chloride%
Examples include I-licasenate, polyester resin, I-lyamide resin, phenol resin, xylene resin, alkyd resin, wax, polyolefin, and wax.

After the above-described plate-making process is completed, 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, allowing normal lithographic printing! −
In this case, the oil-based ink adheres only to the image area, and good printed matter without background stains can be obtained.

Furthermore, the printing original plate of the present invention has particularly high sensitivity compared to conventional printing original plates, and due to the selection of the charge-generating substance, He-N
Direct plate making is possible using various light sources such as e-lasers and semiconductor lasers.

Next, 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: On a polyester film having a thickness of about 100 pm on which aluminum was vapor-deposited, 10 parts of a charge transporting substance represented by the following structural formula (I) and a polycarbonate resin (
A solution consisting of 10 parts of K-1300 (manufactured by Ryotai Kasei Co., Ltd.) and 80 parts of tetrahydrofuran was applied, followed by drying at 80°C for 2 minutes and then at 105°C for 5 minutes to form a charge transport layer with a thickness of about 17 μm. .

On this charge transport layer, 1 part of a disazo pigment represented by the following structural formula (II) and 100 parts of a double tetrahydrofuran solution of methyl vinyl ether-maleic anhydride copolymer (manufactured by Aldrich Chemical Company) were placed in a ball mill. Add toluene-2 to the dispersion that has been thoroughly ground and mixed.
, 4-diisocyanate) was applied, dried at 90°C for 5 minutes, and then heat-treated at 150°C for 1 hour to form a charge-generating layer with a thickness of about 0.8 μm that can be converted into residual water. Formed.

(II) The lithographic printing original plate thus obtained was positively charged by applying +6 KV corona discharge for 20 seconds using an electrostatic copying paper testing device (Kawaguchi Electric Seisakusho Co., Ltd. H8P-428 model). Leave it in a dark place for 20 seconds, and the surface potential Vp at that time
o (yR rt), then irradiate the surface with light using a tungsten lamp at an illuminance of 4.5 lux, and find the time (seconds) until the surface potential becomes 1/2 of Vpo. , the half-reduced exposure amount E1/2 was calculated.

The result is Vpo = +1820 (N root), Ff'/
, = 36 (lux seconds).

Next, this printing original plate was heated to approximately 800% by corona discharge in a dark place.
After the gel was charged, it was imagewise exposed using a tangent light source, and the resulting electrostatic latent image was developed with toner and fixed by heating to form a toner image.

Next, in order to make the non-image area of the printing original plate on which the toner image was formed hydrophilic, it was immersed in a triple ft% aqueous sodium metasilicate solution for 20 seconds, washed with water, and dried.

When the printing plate thus prepared was printed using a Ricoh offset printing machine model AP-1310 according to a conventional method, more than 3,000 clear prints without background stains were printed.

Example 2 A solution consisting of 10 parts of a charge transporting substance represented by the following structural formula (It), 10 parts of polycarbonate resin (same as in Example), and 80 parts of tetrahydrofuran was deposited on a 100 μm thick polyester film on which aluminum was vapor-deposited. was applied for 2 minutes at 80°C and dried for 5 minutes at 105°C to form a charge transport layer approximately 18μ thick.

On this charge generation layer, 1 part of a disazo pigment represented by the following structural formula (IV) and 2 parts of a 1N, N-dimethylformamide solution of 2 parts by weight of methyl vinyl ether-maleic anhydride copolymer (manufactured by Aldrich Chemical Kannozoni Co., Ltd.) are applied.
00 parts were thoroughly ground and mixed in a ball mill, a dispersion of 0.22 parts of toluene-2,4-diisocyanate was applied, dried at 105°C for 5 minutes, and further 15
A heat treatment was performed at 0° C. for 1 hour to form a hydrophilic charge generation layer having a thickness of about 08 μm.

Regarding the printing original plate obtained in this way, implementation-1'
Similarly, when Vpo and E1/2 were measured, V
po ==++ 590 (g ruto), E]/2=38
(looks seconds).

A toner image was formed on this original plate in the same manner as in Example 1, and then the non-image area was made hydrophilic to form a printing plate. When printed on a printing press, clear prints with no background stains were obtained at 3.0%.
I was able to print over 00 pages.

Example 3 A charge transport layer was formed in the same manner as in Example 2 on a 100 μm thick polyester film coated with aluminum. On top of this, 1 part of a trisazo pigment represented by the following structural formula (V) and 2% by weight N,N-dimethylformamide solution of 1 part of methyl vinyl ether-maleic anhydride copolymer (manufactured by Aldrich Chemical Company) were added.
0.22 parts of toluene-2,4-diisocyanate was added to a dispersion solution prepared by thoroughly pulverizing and mixing 1 part in a H-mill mill, and dried at 105°C for 5 minutes.
C. for 1 hour to form a parent, hydratable charge generating layer with a thickness of about 0.8 .mu.m.

Regarding the planographic printing original plate thus obtained, Vpo and E]/2 were measured in the same manner as in Example 1.
po = -4-1690 (delt), B'/=2.4 (
looks/seconds).

Further, after forming a toner image in the same manner as in Example 1,
The non-image area was made hydrophilic by immersing it in a solution prepared by diluting 1 part of PS plate developer DP-4 (manufactured by Fuji Photo Film Co., Ltd.) with 8 parts of water for 20 seconds.

When this printing plate was printed on a printing press, more than 3,000 clear prints with no background stains were printed.

Effects As described above, according to the present invention, a printing original plate having high sensitivity, high printing durability, and easy plate making can be obtained.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the basic structure of the printing original plate for electrophotographic engraving of the present invention. FIGS. 2 and 3 are diagrams explaining the plate-making process of the printing original plate of the present invention. FIG. 2 shows a state in which a toner image has been formed, and FIG. 3 shows a state in which a non-image area has been made hydrophilic. . ]...Conductive support 2...Charge transport layer 3...Hydrophilic charge generation layer 4...Toner image 5...Image 1 of the portion of the charge generation layer that has been made hydrophilic Atsushi figure 2

Claims (1)

[Claims] 1. A charge transporting layer containing a charge transporting substance as a main component is provided on a conductive support, and the surface made of a charge generating substance and a reaction product of a resin having an acid anhydride ring structure and a crosslinking agent can be made hydrophilic. 1. A printing original plate for electrophotographic engraving, characterized by being provided with a charge generation layer.