JPS61217294A - Blate 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, then a layer comprising an electric charge generating substance and a specified resin is provided thereon, and further the latter layer is thermally treated to form an electric charge generating layer. CONSTITUTION:The charge feeding layer 2 comprising a charge feeding substance as a main constituent is provided on the conductive base 1, a layer comprising a charge generating substance and a resin having an acid anhydride ring structure with part of the acid anhydride rings opened is provided thereon, and the latter layer is thermally treated to form the charge generating layer 3 the surface of which can be made hydrophilic. The thermally treated resin, per se, is hydrophobic and has sufficient resistance for holding an electrostatic latent image, but when it is treated with 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 hydrophilic but not water-soluble and has sufficient water resistance, high 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 printing, and more particularly 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.

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, requiring the operation of first creating negatives or positives from the original using silver halide film. However, there are drawbacks such as requiring large-scale equipment and time-consuming plate making.

In addition, printing plates using diffusion transfer development or hardening development methods for silver halide photosensitive materials have the disadvantage that direct plate making is possible, and the printing time is less than 1 month, and the cost per sheet is high.

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. 51-157
66 and Japanese Patent Publication No. 51-25761, a zinc oxide-resin dispersion printing plate is known. After forming a toner image on this printing plate by electrophotography, it is treated with, for example, an acidic aqueous solution containing ferrocyanate in order to make the non-image area 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 urinary layer on the surface. , its printing durability is 000~10
,000 sheets.

In addition, zinc oxide/resin dispersion printing plates are either dye-sensitized in order to have sensitivity in the visible light region, or even then do not exhibit sensitivity that can withstand Amagawa in the long wavelength light region of 600 nm or more. Therefore, low-power and inexpensive He-N
The drawback is that it cannot be exposed using an e-racer or a semiconductor laser. On the other hand, Tokuko Sho 37-17162, Tokko Sho 38-7758
, JP 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
, Japanese Unexamined Patent Publication No. 57-161863, etc., for example, a hydrophilic conductive material such as a grained aluminum plate,
A layer consisting of an organic photoconductive compound and an alkali-soluble resin on a columnar support, or a layer in which a charge-generating pigment such as a lid or a cyanine pigment is dispersed in an alkali-soluble resin, or an electron-withdrawing substance is added to this dispersed layer. Alternatively, a printing original plate for electrophotographic engraving is shown, which is provided with a layer sensitized by adding an electron donating substance. 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. 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.

Furthermore, Japanese Patent Publication No. 5606/1989 discloses a method for preparing a printing plate with hydrophilic treatment on the surface of the non-image area, which is easy to plate-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 and ring-opening the acid anhydride top area with water after the toner image is formed.

However, the vinyl ether-maleic anhydride copolymer used here becomes water-soluble when the top part of the acid anhydride is ring-opened and made hydrophilic, so high printing durability could not be achieved. .

If the proportion of hydrophobic resin in the layer is increased in order to improve water resistance, the hydrophilicity of the surface will decrease, causing stains on the surface of the object, making it difficult to achieve both hydrophilicity and water resistance. Met.

Purpose The purpose of the present invention is to solve the above-mentioned problems of conventional printing original plates for electrophotographic engraving, and to provide a printing MLJ original plate that has particularly high sensitivity, high printing durability, and is easy to make. be.

Structure: The printing original plate for electrophotographic plate making of the present invention has a charge transporting layer Zzs, yz containing a charge transporting substance as a main component on a conductive support.
A Ti blade L transport layer is provided, and a layer made of a charge generating substance and a resin having an acid anhydride ring structure, with a part of the acid anhydride ring opened, is provided thereon, and further the resin layer is It is characterized by providing a charge generation layer whose surface can be made hydrophilic by heat treatment.

Here, typical examples of resins having an acid anhydride ring structure include:
A copolymer containing maleic anhydride as one copolymerization component (
(hereinafter abbreviated as maleic anhydride copolymer).

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 the light in the portions irradiated with light, and electrons and holes are generated.

Electrons and holes are injected by the electric field into the charge transport layer 2, through which they flow to the conductive support, where they neutralize the surface charge and form an electrostatic latent image. At this time,
The surface of the layer 3 that holds static* and latent images needs to be highly resistive and hydrophobic to the extent that charge diffusion in the surface direction does not occur (if it is hydrophilic, the resistance will be low due to the adsorption of water). , electrostatic latent images cannot be retained).

The electrostatic latent image is then developed with toner charged to the opposite polarity to the surface charge and viewed 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 30 needs to be hydrophilic during printing.

In this way, the layer 3 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 heat-treated resin having a partially ring-opened acid anhydride group used for layer 3 in the present invention is originally hydrophobic and has sufficient resistance to retain an electrostatic latent image. When treated with an alkaline aqueous solution, the top portion of the acid anhydride undergoes ring opening by hydrolysis, becoming hydrophilic and printing possible. 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; Examples include organic compounds shown in (1) to α4 below.

(1) Malachite green, crystal/? Triphenylmethane dyes such as iolet, thiazine dyes such as methylene blue and methylene green, astrazone dyes such as Astrazone Orange R1, Astrazone Yellow 3GL, and Astrazone Red 6B, cyanine pigments such as Eisen Astrafuroxin FF, Rhodamine B, etc. xanthine pigment, 2,6-diphenyl-4-(N,
, N-dimethylaminophenyl) thiapyrylium verchlorate, and pyrylium dyes such as thiapyrylium 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.

(Transformation) A charge-transfer type complex consisting of an electron-donating substance such as poly-N-vinylcarnozole and an electron-accepting substance such as 2,4,7-dolinitrofluorenone.

(b) A eutectic complex formed from a pyrylium salt dye and a polycarbonate resin.

(2) Barbyric acid derivatives or naoparbituric acid derivatives.

(c) Azo pigments such as monoazo pigments, disazo pigments, and trisazo pigments. Examples of monoazo pigments include monoazo pigments having a central skeleton such as anthraquinone and N-phenylcarnozole, and examples of disazo pigments include benzidine pigments such as Diane Blue and Chlordiane Blue, or N-ethylcarbazole. , stilbene, distilbenzene, naphthalene, fluorenone, fluorene, anthraquinone, 2,5-diphenyl-
1,3゜4-oxadiazole, dipenzothiophene,
Disazo pigments with core skeletons such as dibenzothiophene dioxite, acridone, and phenanthrenequinone are
Examples of trisazo pigments include trisazo pigments having a central skeleton of triphenylamine or N-phenylcarnozole.

As the resin having an acid anhydride ring structure used in the charge generating layer 3 that can be made hydrophilic, is a copolymer containing maleic anhydride as one copolymer component as described above suitable?More specifically, Toeha, methyl vinyl ether, ethyl vinyl ether, 2-chlorovinylethyl ether,
Propyl vinyl ether, inbutyl 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 monomaleic anhydride, copolymers of vinyl acetate and maleic anhydride etc., and in these copolymers, a partially opened version of the acid anhydride ring is used.

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, and 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-
Oxadiazole compounds such as (9-ethylcarbazole-3-)-5-(4-diethylaminophenyl)-1,3,4-oxadiazole, 2-vinyl-4-(2-
Oxazole compounds such as chlorophenyl)-5-(4-diethylamino)oxazole, 2-(4-diethylaminophenyl)-4-phenyloxazole, 1-phenyl-3-(4-diethylaminostyryl)-S-(
4-/ethylaminophenyl)pyrazoline, 1-phenyl-a-(4-dimethylaminostyryl)-5-(4-
pyrazoline compounds such as dimethylaminophenyl) pyrazoline, 2,2'-dimethyl-4,4'-bis(diethylamino)triphenylmethane, 1,1-bis(4-di4ndylaminophenyl)propane, tris( Diphenylmethane compounds such as 4-diethylaminophenyl)methane, fluorene compounds such as 9-(4-dimethylaminobenzylidene)fluorene, 3-(9-fluorenonedene)-9-ethylcarbazole, 9-(4-diethylaminostyryl)anthracene, 9-Brom-10-(
styryl anthracene compounds such as 4-diethylaminosteryl) anthracene, distyrylbenzene compounds such as 1,2-bis(4-diethylaminostyryl)benzene, 1,2-bis(2,4-dimethoxystyryl)benzene, 9-ethylcal・Tazole-3-aldehyde 1
-Methyl-1-phenylhydrazone, 9-ethylcarba ζzole-3-aldehyde 1-(Fuji-1-phenylhydrazone, 4-diethylaminobenza!redehyde 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-dibenzylaminosterpene, 4-ditolylaminostilbene, 1-(4-diphenylaminostyryl)naphthalene, 1-(4-diphenylaminostilbene), 1-(4-diphenylaminostyryl)naphthalene, styrylnaphthalene compounds such as benzylaminostyryl) naphthalene, 4'-diphenylamino-a-phenylstilbene, α-phenylstilbene compounds such as 4'-methylphenylamino-α-phenylstilbenato, 3-styryl-9-ethylcarbazole, A polymer compound such as a styrylcarnozole compound such as 3-(4-diethylamino)styryl-9-ethylcarbasolnato or poly N-vinylcarnozole is used.

Examples of the electron transport substance include chloranil, bromoanil, tetracyanoethylene, tetracyanoquinone dimethane, 2,4,7-dolinitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone,
2,4,5.7-tetranitroxanthone, 2,4.8
-) linitrothioxanthone, 2,6.8-trinitro-4H-indeno[1,2-Blthiophen-4-one, 1,3.7-trinitrodipenzothiophene-5,5
- Examples include dioxide.

Examples of the binding resin include polyester resin, polycarbonate resin, acrylic resin, polystyrene, polyamide, acrylamide, polyvinyl acetal, and polyvinyl butyral.

Conductive support 1 (!: Plastic film with a conductive surface such as an aluminum vapor-deposited film; water-resistant/solvent-resistant treated and S*-treated paper; aluminum plate, zinc plate, copper plate, stainless steel plate) Metal plates such as are used.

In order to produce the electrophotographic printing plate of the present invention, the above-mentioned charge transporting substance and binding resin are mixed with organic solvents such as tetrahydrofuran, dioxane, dimethylformamide, acetone, menal ethyl ketone, and ethylene glycol. A solution dissolved in monomethyl ether, ethylene glycol monoethyl ether, ethyl acetate, butyl acetate, toluene, halogenated hydrocarbon, etc. is applied onto the conductive support and dried to provide the charge transport layer 2.

Next, a charge generating substance is added to a solution in which a partially ring-opened maleic anhydride copolymer is dissolved in the same organic solvent as above.
A coating liquid uniformly dispersed by a dispersing means such as a ball mill or an ultrasonic dispersion machine is applied onto the charge transport layer, dried, and further heat-treated to form the charge generation layer 3.

The temperature and time of this heat treatment vary depending on the type of maleic anhydride copolymer and the degree of ring opening, or approximately 80%
The temperature can be selected from several minutes to several hours at a temperature of .degree. C. to 200.degree.

Hydrophilic charge generation No. 3 is made of a charge generation substance and a maleic anhydride copolymer as a living body, or it is made of other resins such as polyester resin, polyamide resin, polycarbonate resin, etc. to improve the strength of the layer. 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 rate of hydrophilic treatment of the surface of the non-image area after image formation will be slow and the hydrophilicity will be insufficient, resulting in background stains on the printed matter.

The proportion of the charge generating substance in the hydrophilic charge generating layer 3 is as follows:
Preferably 10~SOZ amount% - more preferably 20~
It is 70% by weight. Below this range, sensitivity is low, and above this range, printing durability is reduced. The thickness of the charge generation layer 3 is preferably 0.05 to 5 pm, more preferably 0.1 to 2 pm. Below this range, the sensitivity is still low, and above this range, the residual potential is high and causes staining of the background.

The proportion of charge transport material in the charge transport layer 2 is between 10 and 95% by weight, preferably between 30 and 90% by weight. Below this range, the sensitivity is low, and above this range, the mechanical strength of the layer decreases, making it unsuitable for practical use. The thickness of the charge transport layer 2 is preferably 3 to 50 μm, more preferably 5 to 20 μm.
．． It is pm. 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 plate making of the printing original plate for electrophotographic platemaking of the present invention is carried out in accordance with the usual electrophotographic method, and is uniformly charged in a dark place using a corona charger or the like.
Electrostatic latent images are formed by reflection image exposure using a light source such as a xenon lamp or fluorescent lamp, contact image exposure through a transparent positive film, or scanning exposure with laser light such as a He-Ne laser, argon laser, or bull conductor laser. This 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-generating M3) is made hydrophilic, and a good printing plate is obtained. can get. (Figure 3) The hydrophilic treatment liquid used here is, for example, an alkaline aqueous solution of inorganic salts such as sodium silicate, sodium phosphate, sodium hydroxide, and sodium carbonate, or an alkaline aqueous solution containing organic amines such as triethanolamine and ethylenediamine. A solution to which an organic solvent such as ethanol, benzyl alcohol, ethylene glycol, or chrycerin or a surfactant or the like is added 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, or 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 hydrophilic treatment only on the non-image areas, it is preferable that the toner component contains a resin component having resist properties in the hydrophilic treatment liquid.

This resin component may be anything that is insoluble in the eluate, such as acrylic resin using methacrylic acid, methacrylic acid ester, 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, polystyrene, copolymers of styrene and butadiene, methacrylic acid ester, etc., polyethylene, polypropylene and their chlorides,
Examples include polycarbonate, polyester resin, polyamide resin, phenol resin, 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.

In addition, 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 "r parts" in the examples represent parts by weight.

Example 1 On a polyester film having a thickness of about 10 μm on which aluminum was vapor-deposited, a charge transporting material represented by the following structural formula (la part), a polycarbonate resin (panlite-1
A solution consisting of 1 part of 300 (manufactured by Ryotaikasei Co., Ltd.) and 80 parts of tetrahydrofuran was applied, heated at 80°C for 2 minutes, and dried at 1.05°C for 5 minutes to form a charge transport layer with a thickness of about 17 μm. did.

C,H.

On this charge transport layer, 1 part of a disazo pigment represented by the following structural formula (I 100 g of the dispersion was thoroughly ground and mixed using a ball mill, dried at 90°C for 5 minutes, and further heat-treated at 150°C for 1 hour to form a hydrophilic charge generation layer with a thickness of about 0.8 μm. .

11+7 The lithographic printing original plate thus obtained was subjected to +6KV corona discharge for 20 seconds using an electrostatic copying paper tester (S P-428 model manufactured by Kawaguchi Electric Seisakusho Co., Ltd.), and the result was exactly ¥Wt.
After this, the surface potential was left in a dark place for 20 seconds, and the surface potential Vpo (volts) was measured. Then, the surface was irradiated with light using a tungsten lamp at an illuminance of L5 lux, and the surface potential was Vpo/Vpo. The time (6) until the value becomes 2 was determined, and the half-reduction exposure amount B1/2)Ir- was calculated. The result is Vpo=+18, QO(,j?/L/
, ) ), E'/2 = 3.6 (7L/ tsu, y
vinegar.

seconds).

Next, this printing original plate was heated to approximately 800% by corona discharge in a dark place.
After the bolt was charged, imagewise exposure was performed using a tungsten 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, 2% sodium metasilicate was added to the 3% by weight aqueous solution of sodium metasilicate.
It was immersed for 0 seconds, washed with water, and dried.

Using the printing plate %l Coco Offset Printing 1AP-1310 model made in this manner, printing was performed according to a conventional method, resulting in clear printed matter with no background stains 4 a, o o
I was able to print more than o pages.

Example 2 A solution consisting of 10 parts of a charge transporting substance represented by the following structural formula (Il+1), 10 parts of polycarbonate resin (same as in Example 1), and 80 parts of tetrahydrofuran was applied onto a polyester film having a thickness of 1100 p on which aluminum was vapor-deposited. , and dried 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 18 μm.

On this charge generation layer, 1 part of a disazo pigment represented by the following structural formula (F/) and 2 parts by weight of a partially ring-opened methyl vinyl ether-maleic anhydride copolymer (manufactured by Aldrich Chemical Company), 4N, N- A dispersion of 100 parts of dimethylformamide solution thoroughly ground and mixed in a ball mill was coated, dried at 105°C for 5 minutes, and further dried for 15 minutes.
A heat treatment was performed at 0° C. for 1 hour to form a hydrophilic charge generation layer having a thickness of about 0.8 μm.

Regarding the printing original plate obtained in this way, Vpo and E1/2 were measured in the same manner as in Example 1.
= +1550 (volts), El/2 = 3.8
(/l/l tax).

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.
I was able to print 0 or more pages.

Example 3 A charge transport layer was formed in the same manner as in Example 1 on a polyester film having a thickness of 1100 P on which aluminum was vapor-deposited. On top of this, 1 part of a trisazo pigment represented by the following structural formula (V) and a partially ring-opened methyl vinyl ether-maleic anhydride copolymer (Aldrich Fist Chemical Co., Ltd.)
A dispersion of 100 parts of 2fii-N,N-dimethylformamide solution (manufactured by Nippon Airways Co., Ltd.) thoroughly ground and mixed in a ball mill was coated, dried at 105°C for 5 minutes, and then
The lithographic printing original plate thus obtained was heat-treated at 0°C for 1 hour to form a hydrophilic charge-generating layer with a thickness of about 0.8 pm. When Vpo and E1/2 were measured, V
po=:41720 (volt) E”/2= z a
(looks Φ 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 copies were printed, with no background stains and clear prints.1>--26-.

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. . 1... Conductive support 2... Charge transport layer 3.
...Hydrophilic charge generation M4...Toner image 5.
...Hydrophilized partial agent of charge generation layer 1 Figure tail 2 solid A119-

Claims (1)

[Claims] 1. A charge transporting layer containing a charge transporting substance as a main component is provided on a conductive support, and a charge generating substance and a resin having an acid anhydride ring structure and a part of the acid anhydride ring are provided on the charge transporting layer. 1. A printing original plate for electrophotographic engraving, characterized in that a layer made of a ring-opened resin is provided, and the resin layer is further heat-treated to form a charge generation layer whose surface can be made hydrophilic.