JPS60235141A - Original printing plate for electrophotographic engraving - Google Patents

Abstract

PURPOSE:To improve sensitivity and resistance to printing and to obtain satisfactory printed matter having no ground stains by providing a photosensitive layer consisting of two layers, an electric charge generating layer contg. a specific azo pigment and an electric charge transfer layer contg. an electric charge transfer material and alkali soluble resin on a conductive base. CONSTITUTION:The photosensitive layer 2 consisting of the two layers; the electric charge generating layer 3 contg. the azo pigment expressed by the formula (Ar is 1,4-, 1,3- or 1,2-phenylene, A is the residual coupler group) and the electric charge transfer layer 4 contg. the charge transfer material and alkali soluble resin is provided on the conductive base 1. Such layer 2 is subjected to formation of an electrostatic latent image, toner development and heat fixing, by which a toner image is obtd. Such layer is then processed by an alkali eluting liquid by which the hydrophilic surface of the base 1 is exposed and the image part coated by the oleophilic toner is left. Oil ink sticks only to the image part and the sharp image having no ground stains is obtd. if the original printing plate obtd. in such a way is used for, for example, lithographic printing. Such layer 2 has high sensitivity, permits direct photoengraving with various light sources and has excellent resistance to printing.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a novel printing plate that can be made by electrophotography. More specifically, with a new printing plate containing all of a specific azo pigment, the electrostatic latent image obtained by charging and subsequent image exposure is developed with toner, fixed to obtain a toner image, and then the non-image area is This invention relates to a printing plate that is made by elution and removal of a photosensitive layer.

BACKGROUND ART Conventionally, as master plates for lithographic printing, those using photosensitive resins and silver halide photosensitive materials are known.

However, although lithographic printing plates made using photosensitive resin have high printing durability, they have low sensitivity and cannot be used in so-called direct plate making, which requires the operation of creating negatives or Po-Zo from the original using silver halide film. However, there are drawbacks such as requiring large-scale equipment and time-consuming plate making.

Further, although printing plates using diffusion transfer development or hardening development methods using silver oxide photosensitive materials can be directly plate-made, they have the drawbacks of low printing durability and high cost per sheet.

Examples of printing plates for direct plate making that fully utilize the electrophotographic method include JP-B No. 47-4761'O, JP-B No. 48-48. −
40002, Special Publication No. 48-1.8325, Special Publication No. 5]
-15766 and Japanese Patent Publication No. 1-25761 are known printing plates having a zinc oxide-resin dispersion system. After the toner image is completely formed on this printing plate by electrophotography, the surface of the printing plate is treated with an acidic aqueous solution containing ferrocyanate in order to make all non-image areas hydrophilic. Printing plates made in this way peel off due to the mechanical pressure applied during printing and the penetration of dampening water into the photosensitive layer and conductive layer, destroying the hydrophilic layer on the surface. The printing durability is 5.
The number of sheets was approximately 10,000 to 10,000.

In addition, zinc oxide/resin dispersion printing plates are subjected to dye sensitization in order to have sensitivity in the visible light region, but even so, the sensitivity is still insufficient 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, the special public service No. 37-17162, the special public service No. 38-7758
, JP 46-39405, JP 52-2437, JP 56-107246, JP 55-105254°, JP 55-15394.8, JP 55-16125
, JP-A-57-147656, JP-A-56-14.61
45, JP-A No. 57-161863, etc., disclose a layer consisting of an organic photoconductive compound and an alkali-soluble resin, or a phthalocyanine-based layer on a hydrophilic conductive support such as a grained aluminum plate. A layer in which a charge-generating pigment such as No. 11 is dispersed in an alkali-soluble resin,
Alternatively, a printing original plate for electrophotographic engraving is disclosed in which the dispersed layer is provided with an electron-donating substance or a layer sensitized by adding an electron-donating substance. This type of printing original plate is made by forming a toner image entirely 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. However, it has the disadvantage that it has low sensitivity as a photoreceptor for electrophotography, resulting in slow plate-making speed and the need to use a high-output light source.

Object The object of the present invention is to solve all the problems of the conventionally known printing plates for electrophotographic engraving as described above, and to provide a printing plate having particularly high sensitivity and high printing durability.

Structure The printing original plate for electrophotolithography of the present invention comprises a charge generation layer containing an azo pigment represented by the following general formula (1) and a charge transport layer containing all of a charge transport substance and an alkali-soluble resin on a conductive support. The entire feature is that an electrophotographic photosensitive layer consisting of two layers is provided.

General formula (1) %Formula% (A, r are 1.4-, 1.3-t or 1,2-phenylene) (However, A represents a coupler residue.)
Basic configuration of the printing original plate for electrophotolithography of the present invention
As shown in the figure. Here, 1 is a conductive support (5), on which a charge generation layer 3 and a charge transport layer 4 are laminated to form the entire electrophotographic photosensitive layer 2.

The charge generation layer 3 and the charge transport layer 4 can also be stacked upside down.

The azo pigment used in the charge generation layer 3 is Cassirer.
For example, compounds with phenolic hydroxyl groups such as phenols and naphthols, aromatic amino compounds with amine groups, aminonaphthols with both amine groups and phenolic hydroxyl groups, or aliphatic or aromatic enolic ketone groups (active methylene A compound with a group] is used,
Preferably, the coupler residue A has the following general formula (II), (
Il'f), (IV), (V), (Vl), (■).

[In the formula, R4 is hydrogen, an alkyl group, a phenyl group, or (6
) is a substituent thereof, X is a hydrocarbon it or a substituent thereof,
Heterocycle or a substituent thereof, Y is a hydrocarbon ring group or a substituent thereof, a heterocyclic group or a hydrocarbon ring group or a substituent thereof, a heterocyclic group or a substituent thereof, or a styryl group'- Also, a substituted product, R3 is hydrogen,
R2 and R3 may represent an alkyl group, a phenyl group, or a substituent thereof, or may form a cash form together with the carbon atom to which they are attached. )] O (R4 in formulas (III) and (IV) represents a substituted or unsubstituted hydrocarbon group.) r1 (wherein R5 represents an alkyl group, a carbamoyl group, a carboxyl group or an ester thereof, In addition, A r 1 represents a hydrocarbon group or a substituted product thereof.) H 1II 60 (wherein, R6 is a hydrocarbon group or a substituted product thereof, A
r 2 represents a hydrocarbon ring group or a substituted product thereof.

) Examples of the hydrocarbon ring for X in the general formula used in the present invention include a benzene ring and a naphthalene ring; examples of the heterocycle include an indole ring, a carbazole ring,
Hydrocarbon ring groups such as benzofuran ring for Y or R2 include phenyl group, naphthyl group, anthryl group,
Examples of heterocyclic groups such as pyrenyl group include pyridyl group, chenyl group, furyl group, indolyl group, benzofuranyl group,
Examples of the ring that can be formed by R2 and R3 together with the carbon atoms to which they are bonded include a carbazolyl group, a dipenzofuranyl group, and a fluorene ring.

Furthermore, examples of the hydrocarbon group for R4 or R6 include alkyl groups such as methyl, ethyl, propyl, and butyl, aralkyl groups such as benzyl, aryl groups such as phenyl, and substituted products thereof. R4
Alternatively, substituents on the hydrocarbon group of R6 include alkyl groups such as methyl group, ethyl group, propyl group, butyl group, alkoxy groups such as methoxy group, ethoxy group, propoxy group, butoxy group, chlorine atom, bromine atom, etc. of··
Examples include a rhodan atom, a hydroxyl group, and a nitro group. R1
As a substituent on the phenyl group or the ring of
Substituents on the ring that can be formed include alkyl groups such as methyl, ethyl, propyl, and butyl; alkoxy groups such as methoxy, ethoxy, propoxy, and butoxy; halogens such as chlorine and bromine; atom, dimethylamino group, diethylamino group, etc. (10) alkylamino group, dialkylamino group such as dibenzylamine group, halomethyl group such as trifluoromethyl group, nitro group, cyano group, carbonyl group or its Examples include ester, hydroxyl group, and sulfonic acid group (-8O3Na). Furthermore, as the hydrocarbon ring group in Ar1 or Ar2, phenyl group, naphthyl group, etc.
Substituents for these groups include alkyl groups such as methyl, ethyl, propyl, and butyl; alkoxy groups such as methoxy, ethoxy, propoxy, and butoxy; nitro; chlorine; and bromine. Examples include halokene atoms such as cyano groups, dimethylamine groups, dialkylamino groups such as diethylamino groups, and the like.

The azo pigment used in the present invention has ρ0, for example,
-86143, JP-A-56-94.356, JP-A-57
-89762, JP-A-57-90056, JP-A-56-
150750 and is described in Japanese Patent Application Laid-open No. 145262/1983. Examples of these azo pigments are as follows.

(13) (14) (17) The charge generation layer 3 is a layer mainly composed of the azo pigment represented by the general formula (I), but it can also contain a binder entirely if necessary. The ratio of the azo pigment in the generation layer is preferably 30% by weight or more.Since the printing original plate of the present invention elutes the non-image area during the plate-making process, it is recommended to use a binder as a binder if a binder is used18). For example, alkali-soluble resins (such as styrene-maleic anhydride copolymers and novolak-type phenolic resins)
I will discuss this in detail later. ) It is preferable to have a full circle. However, if the proportion of the binder is small, it is also possible to use other resinous metals. Further, the thickness of the charge generation layer 3 is preferably 001 to 51 tm, more preferably 0.05 to 2 μm.
It is. If the thickness is less than 0.001 μm, charge generation will not be sufficient, and if it is more than 5 μm, the residual potential will be too high for practical use.

The charge transport layer 4 is formed of a charge transport substance and an alkali-soluble resin. Charge transporting substances include hole transporting substances and electron transporting substances, and examples of hole transporting substances include 2,
5-bis(4-diethylaminophenyl) -1,3,
4-Oxadiazole, 2,5-bis[4-(4-diethylaminostyryl)phenyl, l] -1,3,4-
Oxadiazole, 2-(9-ethylcarbazolyl-3)
-)-5-(4-diethylaminophenyl) -1,3
, 4-oxadiazole, 2-vinyl-4-(2-chlorophenyl)-5-(4
-diethylamino)oxazole, 2-(,4-diethylaminophenyl)-4-phenyloxazolenato oxazole compound, 1-phenyl-3-(4-diethylaminostyryl)-5-(4-diethylaminophenyl)pyrazoline, 1-phenyl -3-(4-dimethylaminostyryl)-5-(4-dimethylaminophenyl)
Pyrazoline compounds such as pyrazoline, 2,2'-tumethyl-4,4'-bis(diethylamino)triphenylmethane, 1,1-bis(4-dibenzylaminophenyl)
Propane, diphenylmethane compounds such as tris(4-diethylaminophenyl]methane, fluorene compounds such as 9-(4-dimethylaminobenzylidene)fluorene, 3-(9-fluorene compound)-9-ethylcarbasol, 9-(4- styryl anthracene compounds such as diethylaminostyryl) anthracene, 9-bromo-10-(4-diethylaminostyryl) anthracene,
Nostyrylbenzene compounds such as 1,2-his(4-diethylaminostyryl)benzene, 1,2-bis(2,4-dimethoxystyryl)benzene, 9-ethylcarbasol-3-aldehyde 1-methyl-1-phenyl Hydrazone, 9-ethylcarbasol-3-aldehyde 1-
Benzyl 1-phenylhydrazone, 4-diethylaminobenzaldehyde 1,1-nonenylhydrazone, 2
,4-dimethoxybenzaldehyde 1-bentrue 1-
Hydrazone compounds such as phenylhydrazone, 4-nophenylaminobenzaldehyde 1-methyl-1-phenylhydrazone, 4-diphenylaminostilbene, 4-
Stilbene compounds such as dibennolaminostilbene and 4-ditolylaminostilbene, styrylnaphthalene compounds such as 1-(4-diphenylaminostyryl)naphthalene, ]-(]4-dibennolaminostyrylnaphthalene, 4'-diphenyl Amino-α-phenylstilbene, α-phenylstilbene compound of 4′-methylphenylamino-α-phenylstilbenato, 3-styryl-9-ethylcarbazole, 3-(4-diethyl(2)
1) A styrylcarzole compound of amino)styryl-9-ethylcarbazole is used.

Examples of electron transport substances include chloranil, bromoanil, tetracyanoethylene, tetracyanoquinone dimethane, 2,4,7-)linitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone, 2, 4,5.7-Titranitroxanthone, 2,4.
8-trinidrothioxanthone, 2.6.8-)dinitro-4H-indeno[I 1,2-b]thiophene-4
-one, 1,3.7-) IJ nitronohenzothiophene-5,5-dioxide, and the like.

The alkali-soluble resin used in the charge transport layer 4 refers to a resin that becomes soluble in an aqueous or alcoholic solvent by completely adding an alkali thereto. For the purposes of the present invention, in addition to properties such as film-forming properties, electrical properties, and adhesion strength to a support, solubility properties are particularly important for these resins. Examples of resins having such characteristics include styrene-maleic anhydride copolymer, styrene-methacrylic acid-methacrylate copolymer, and methacrylic acid-methacrylate (22
) Copolymers, phenolic resins, etc. are exemplified.

Phenol resins include phenol, 0-cresol, m-cresol, p-cresol, ethylphenol, isopropylphenol, t-butylphenol,
t-Aminephenol, hexylphenol, L-octylphenol, cyclohexylphenol, 3-methyl-4-chloro-6-t-butylphenol, isozolovircresol, t-butylcresol, t-amylcresol, hexylcresol, t-octyl A novolac type resin is used, which is obtained by condensing at least one substituted phenol such as cresol and cyclohegycyl cresol with an aldehyde such as formaldehyde, acetaldehyde, acrolein, crotonaldehyde, and furfural under acidic conditions.

The charge transport layer 4 is a layer consisting entirely of a charge transport substance and an alkali-soluble resin, and the ratio of the charge transport substance in the layer is 10 to 10.
70% by weight, preferably 20 to 60% by weight. When the proportion of the charge transport substance is below this range, almost no charge is transported, and when it exceeds this range, the mechanical strength of the layer is extremely poor and cannot be put to practical use. Further, the thickness of the charge transport layer 4 is 2 to 50 μm, preferably 3 to 20 μm. Below this range, the amount of charge is insufficient, and above this range, the residual potential becomes high and it takes a long time to elute the layer, making it impractical.

The charge transport layer 4 can contain all the plasticizer.

Effective plasticizers include, for example, phthalic acid esters such as dimethyl phthalate, diethyl phthalate, butyl phthalate, and glycol esters such as dimethyl glycol phthalate and ethyl phthalyl ethyl glycolate.

These plasticizers can be contained within a range that does not deteriorate the electrostatic properties and alkali solubility of the photoconductive layer.

The conductive support 1 used in the present invention is an aluminum plate, a zinc plate, or a bimetallic plate such as a copper-aluminum plate, a copper-stainless steel plate, a chromium-copper plate, or a chromium-copper-aluminum plate, a chromium-lead plate. -Iron plate, chrome-
A conductive support with a hydrophilic surface such as a tri-metal plate such as a copper-stainless steel plate is used, and its thickness is 0.1
~l mm is preferred.

In addition, especially in the case of a support having an aluminum surface, surface treatments such as graining treatment, immersion treatment in an aqueous solution of IJum, potassium fluorozirconate, phosphate, etc., or anodic oxidation treatment may be applied. It is preferable that this is done frequently. As shown in U.S. Pat. No. 2,714,066, an aluminum plate is immersed in an aqueous sodium silicate solution after graining, and JP-A-47
It is also preferable to carry out an anodic oxidation treatment and then immersion treatment in an aqueous solution of an alkali metal silicate as shown in Japanese Patent No. 5125.

The above-mentioned anodizing treatment is performed, for example, by using an aluminum plate as an anode in an electrolytic solution consisting of a solution of an inorganic acid such as phosphoric acid, chromic acid, sulfuric acid, or boric acid, or an organic acid such as oxalic acid or sulfamic acid, or a salt thereof. This is carried out by flowing Rk.

(25) To produce the printing plate for electrophotographic engraving of the present invention, first, the pigment represented by the general formula CI) and, if necessary, a binder are mixed with, for example, tetrahydrofuran, dioxane, dimethylformamide, acetone, methyl ethyl ketone, or ethylene glycol. The coating liquid is mixed in an organic solvent such as monomethyl ether, ethylene glycol monoethyl ether, ethyl acetate, butyl acetate, toluene, or halodanized hydrocarbon and uniformly dispersed using a dispersion means such as a ball mill or an ultrasonic disperser. The charge generating layer 3 is completely formed by coating the charge generating layer on a transparent support and drying it. Next, a solution prepared by dissolving a charge transport substance and an alkali-soluble resin in the same organic solvent as above is applied onto the entire charge generation layer and dried to form the entire charge transport layer 4.

The plate making of the printing original plate for electrophotographic platemaking of the present invention is carried out by first uniformly charging it in a dark place using a corona charger or the like, using a tungsten lamp, halogen lamp, etc., according to the usual electrophotographic method.
Reflection image exposure using a light source such as a xenon lamp or fluorescent lamp, contact image exposure through the entire transparent positive film, or scanning exposure using laser light such as a He-Ne laser, an argon laser, or a semiconductor laser. This electrostatic latent image is completely formed, developed with toner, and fixed by heating to obtain a toner image on the electrophotographic photosensitive layer (Fig. 2).

Next, when the printing plate on which the toner image has been completely formed is immersed in an alkaline eluent, the electrophotographic photosensitive layer (charge generation layer and charge transport layer) in the non-image area is masked by the toner image. The hydrophilic surface of the conductive support is exposed by dissolution, and only the toner image portion remains, making it possible to obtain a good printing plate as a whole (FIG. 3).

The eluent used here is, for example, an alkaline aqueous solution of inorganic salts such as silicate, sodium phosphate, sodium hydroxide, and sodium carbonate, or an alkaline aqueous solution containing organic amines such as triethanolamine and ethylenediamine, or ethanol. A solution containing all organic solvents or surfactants such as benol alcohol, ethylene glycol, and glycerin is used.

In the printing plate of the present invention, after the toner image is formed, the non-image area 'a [debris] is removed in the eluate, so the toner component contains a resin component having resist properties in the eluate. Preferably.

This resin component may be any material as long as it is insoluble in the eluate; for example, acrylic resin using methacrylic acid, methacrylic acid ester, etc., vinyl acetate resin, vinyl acetate and ethylene chloride, vinyl chloride, etc. Polymers, vinyl chloride resins, vinylidene chloride resins, vinyl acetal resins such as polyvinyl butyral, polystyrene, copolymers of styrene and butadiene, methacrylic acid esters, polyethylene, polypropylene and their chlorides,
Examples include polycarbonates, polyester resins, polyamide resins, phenolic resins, xylene resins, alkyd resins, waxes, polyolefins, and waxes.

The printing original plate of the present invention may also contain a quinonediazide compound such as 0-naphthoquinonediazide or a diazo compound for the purpose of increasing the solubility of the electrophotographic photosensitive layer by full-surface exposure after toner image formation.

In the printing original plate of the present invention, after the plate-making process is completed, the conductive substrate with a hydrophilic surface is exposed in the non-image area, and the image area covered with the oleophilic toner remains. The printing original plate of the present invention has a particularly high sensitivity compared to conventional printing original plates, and is compatible with various types of lasers such as He-Ne lasers and semiconductor lasers. Direct plate making is possible with a light source, and the printing plates obtained thereby have high printing durability.

Next, all embodiments of the present invention will be explained in more detail.

All "parts" in the examples refer to parts by weight.

Implementation ρ11 1 part of Azo Pigment 9 was mixed with 0.0 parts of m-cresol-phenol copolymerized novolac resin (manufactured by Toden Chemical: MP-707).
667 parts of 74wt% tetrahydrofuran solution (29)? - The dispersion obtained by pulverization and mixing in Lumir is applied onto a grain-treated aluminum plate with a thickness of about 0.25 mm and dried at 80°C for 10 minutes to form a charge generation layer with a thickness of about 1 μm. did.

2,5-bis(
09 parts of 1,3,4-oxadiazole (4-diethylaminophenyl), 1.8 parts of styrene-maleic anhydride copolymer (copolymerization molar ratio 1:1, manufactured by Aldrich Chemical Co., Ltd.), and tetrahydrofuran. A solution prepared by mixing and dissolving 132 parts of 132 parts of the original plate was applied, and dried at 80° C. for 20 minutes to form a charge transporting layer having a thickness of about 10 μm, thereby preparing a printing original plate for electrophotolithography of the present invention.

This printing original plate was tested at -6
After performing kV corona discharge for 20 seconds to make it negatively charged, it was left in a dark place for 10 seconds, and the surface potential V at that time. (volts), then irradiate the surface with light using a tungsten lamp at an illuminance of 45 lux,
Measure the time it takes for the surface potential to become 1/2 of (30) vo, and calculate the half-reduction exposure amount E1/
2 (looks/seconds) was calculated. The results are shown in Table-1.

Next, this original printing plate all-electronic copy plate making machine (Ricoh S-1
A clear toner image was completely formed on the charge transport layer by charging, imagewise exposure, development and fixing.

This original plate was mixed with 70 g of sodium metasilicate and 14 g of glycerin.
('1 ml, 550 ml of ethylene glylenol, and 150 ml of ethanol) for 1 minute, and was further washed with water while gently brushing to remove all of the electrophotographic photosensitive layer in the non-image areas to which toner was not attached.

The printing plate made in this way was printed on an offset printing machine (
When printing was carried out using a Ricoh AP-1310 model using a conventional method, more than 50,000 clear prints could be printed.

Examples 2 and 3 Printing for electrophotographic printing of the present invention was carried out in the same manner as in Example 1, except that the compounds shown in Table 1 were used as the azo pigment used in the charge generation layer and the charge transport substance used in the charge transport layer, respectively. Created the entire original version, v.

and E1/2 were measured.

The above results are shown in Table-1.

Example 4 Azo pigment A, 1 part of 19f, m-cresol-phenol copolymerized novolac resin (manufactured by Toden Chemical: MP-70
667 parts of the 0.74 wt% tetrahydrofuran solution of 7) was pulverized and mixed in a ball mill, and the resulting dispersion was applied onto a grain-treated aluminum plate with a thickness of about 0.2 mm and dried at 80° C. for 10 minutes. A charge generation layer having a thickness of about 1 μm was entirely formed.

3-styryl- as a charge transport substance on this charge generation layer.
1.5 parts of 9-ethylcarbazole, m-cresol-phenol copolymerized novolac resin (manufactured by Toden Chemical: MP-
707) A solution prepared by mixing and dissolving 30 parts of tetrahydrofuran and 120 parts of tetrahydrofuran was applied completely, heated at 80°C for 2 minutes, and then heated at 80°C for 10 minutes.
It was dried at 0° C. for 10 minutes to completely form a charge transport layer having a thickness of about 10 μm, thereby completing a printing original plate for electrophotolithography of the present invention. Regarding this printing original plate, V was used in the same manner as in Example 1. and E1/2. The results of all measurements are shown in Table 2.

Next, after a toner image was completely formed on the electrophotographic photosensitive layer of this printing original plate in the same manner as in Example 1, it was immersed in a solution consisting of 25 parts of sodium metasilicate and 100 parts of water for about 45 seconds, and then lightly blown with water. The electrophotographic photosensitive layer in the non-image area was completely removed by washing while brushing.

When all of the printing plates made in this manner were printed on an offset printing machine, more than 50,000 clear prints could be printed.

Examples 5 to 8 Printing for electrophotographic printing of the present invention was carried out in the same manner as in Example 4, except that the compounds shown in Table 2 were used as the azo pigment used in the charge generation layer and the charge transport substance used in the charge transport layer, respectively. The original version was created in its entirety.■.

and E172 were measured.

The above results are shown in Table-2.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing the basic structure of the printing original plate for electrophotographic engraving of the present invention. Figures 2 and 3 are diagrams explaining the plate-making process of the printing original plate of the present invention. Figure 2 shows the entire state in which a toner image has been formed, and Figure 3 shows the state in which the non-image area has been completely eluted and removed. . 1... Conductive support, 2... Electrophotographic photosensitive layer, 3...
... Charge generation layer, 4... Charge transport layer, 5... Toner image. Patent applicant Rico Co., Ltd. - (37) Figure 1 Figure 2 Figure 3

Claims (1)

[Scope of Claims] An electrically conductive support consisting of two layers: a charge generation layer entirely containing an azo pigment represented by the following general formula (1), and a charge transport layer containing a charge transport substance and an alkali-soluble resin. A printing original plate for electrophotographic engraving characterized by being provided with an electrophotographic photosensitive layer. General formula (1) (Ar is 1.4-, 1.3-- or 1,2-phenylene) (However, in the formula, A represents a coupler residue.)