JPH03164739A - Electrophotographic printing plate - Google Patents

Abstract

PURPOSE:To prevent occurrence of image defects due to scratches on a photoconductive layer by forming a resin layer on the side of a support reverse to the photoconductive layer. CONSTITUTION:The electrophotographic printing plate material is formed into a printing plate by forming a toner image, and removing a nonconductive layer in nonimage parts. The resin to be formed on the reverse side of the support to the photoconductive layer is not especially limited, and both of alkali-soluble resins and difficultly soluble resins may be used, and it is preferred to use an antistatic layer as the resin layer and also to use a conductivity-enhancing agent. Layers formed by using various kinds of ultraviolet hardenable photopolymerizable compositions can be used, thus permitting occurrence of image defects due to scratches on the photoconductive layer caused in the case of handling the photoconductive layer in contact with the reverse side of the other photoconductive layer.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention has a photoconductor layer on a support, and after a toner image is formed on the photoconductor layer by electrophotography, a It relates to a material (original plate for electrophotographic printing) that becomes a printing plate by removing the photoconductor layer in the image area.

[Conventional technology]

The original plate for electrophotographic printing is JP-A No. 63-267954,
As is known from JP-A No. 63-271481 and JP-A-1-134469, it has a structure in which a photoconductor layer is provided on a support, and toner is deposited on the photoconductor layer by electrophotography. After forming an image, the non-image area is removed using an alkaline solution or the like to create a printing plate, but it is extremely sensitive to scratches. For example, not only scratches that can be detected visually, but also scratches that cannot be detected visually due to rubbing can have an electrostatic effect, affect the amount of toner adhesion, and cause elution of the photoconductor layer in non-image areas. Sometimes, even though the toner should remain as an image, because the amount of toner attached is small, it is eluted at the same time, resulting in image defects.

As a technique that is recognized to be related to the prevention of damage to the photoconductor layer, a technique of providing a protective layer on the surface of the photoconductor layer has been disclosed (Japanese Patent Laid-Open Nos. 59-176756 and 60-112).
However, these methods have drawbacks such as the need to increase elution conditions (increase in alkali concentration, prolongation of immersion time, increase in temperature, etc.) and decrease in sensitivity.

[Purpose of the invention]

SUMMARY OF THE INVENTION The present invention aims to provide a technique for preventing scratches on a photoconductor layer that eliminates the drawbacks of the above-mentioned known techniques. An object of the present invention is to provide an original plate for electrophotographic printing in which image defects caused by sticking are improved.

[Structure of the invention]

The object of the present invention is to provide an original plate for electrophotographic printing in which the photoconductor layer in the non-image area is removed after toner image formation to obtain a printing plate, in which a resin is applied to the surface opposite to the photoconductor layer with a support in between. This is achieved by an electrophotographic printing original plate characterized by being provided with a layer.

The present invention will be explained in detail below.

In the present invention, there are no particular restrictions on the resin that forms the resin layer provided on the surface (back surface) of the support opposite to the photoconductor layer.
It may be a resin that is soluble in alkali or a resin that is sparingly soluble in alkali.

In the present invention, as the resin layer provided on the back surface of the support,
It is particularly preferable to use the antistatic layer (antistatic layer) described in JP-A Nos. 55-84658, 61-174542, and 61-174542. The partial layer may include a conductive polymer (e.g. 35 to 100 parts by weight of a copolymer of the sodium salt of styrene sulfonic acid and maleic acid in a molar ratio of 3:1), a hydrophobic polymer (e.g. methacrylic acid and acrylic acrylate, styrene, 65 to 0 parts by weight of a multicomponent anionic copolymer with one or more heptamers selected from the group consisting of acrylonitrile and alkyl methacrylates) and a multifunctional aziridine crosslinking agent (e.g. pentaerythritol-tri[β-(
N-aziridinyl)propionate] from 2.5 to 30.
0 parts by weight), optionally containing additives such as plasticizers, lubricants, surfactants, etc., or a conductive polymer (e.g. poly(sodium styrene sulfonate) ) - Contains, formed from a Yaftin binder, and optionally contains surfactants, wetting agents,
This is a layer provided with an auxiliary layer containing a hardening agent for gelatin, etc., and the above-mentioned publication can be referred to for details.

It is also desirable that the resin layer of the present invention contains a conductive agent.

As the conductive agent, metal powder or carbon black is preferable, and among the metal powders, silver, silver oxide, silver nitrate, organic compound of silver, and copper powder are preferable.

The reason why it is preferable to make the resin layer of the present invention electrically conductive as described above is because it has the advantage that it can be grounded from the back surface.

The resin layer of the present invention may also be a layer formed using various known photopolymerizable compositions that are cured by ultraviolet rays.

This photopolymerizable composition consists of a seven-mer oligomer having a carbon-carbon unsaturated bond or a compound having an epoxy group, a photosensitizer, a thermal polymerization inhibitor and, if necessary, a polymeric binder.
Contains fillers and additives. Examples of the seven acids include acrylic acid, methacrylic acid, itaconic acid, methyl acrylate and its homologues, acrylic acid alkyl esters, methyl methacrylate and its homologs, methacrylic acid alkyl esters, styrene and its homologs. Certain α-methylstyrene, β-chlorostyrene, etc.
Examples include acrylonitrile, methacrylate trile, acrylamide, methacrylamide, vinyl acetate, vinyl propionate, and the like.

There may be two or more unsaturated bonds in the molecule.

In particular, unsaturated esters of polyols, such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, ethylene glycol diacrylate, butquinethyl acrylate, 14-butanediol diacrylate, 1,6-hexanediol acrylate, stearyl acrylate, - Ethylhexyl acrylate, tetrahydrofurfuryl methacrylate, diethylene glycol diacrylate, diethylene glycol dimethacrylate, tetraethylene glycol diacrylate, neopentyl glycol methacrylate, neopentyl glycol diacrylate, glycerol trimethacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate , ethylene glycol dimethacrylate, pentaerythritol tetramethacrylate, dipentaerythritol hexaacrylate, and glycidyl methacrylate having an epoxy ring.

As the oligomer, an oligomer having one or more of the above-mentioned heptads as a constituent unit can be used.

As a compound having an epoxy group, JP-A-62-21
The compound described in No. 150 is utilized.

Examples of photosensitizers include benzophenone derivatives, benzoin derivatives, anthraquinone derivatives, aldehydes, ketones,
Sulfur compounds, halogen compounds or dyes such as methylene blue and riboflavin can be used.

As the thermal polymerization inhibitor, hydroquinone derivatives, phenol derivatives, nitro-substituted benzenes, tertiary amines, and phenothiazine derivatives are used.

Fillers or additives include colloidal silicate, calcium carbonate, magnesium carbonate, fine powder of inorganic substances such as iron oxide, polyvinyl acetate, poly(meth)acrylate, polyurethane, polyethylene, polypropylene, polyvinyl chloride, Vinyl polymers such as polyvinylidene chloride, uncured russol phenol-based, urea-based, melamine-based, epoxy-based, unsaturated polyester-based resins, and the like.

The resin layer can be formed by dissolving or dispersing the photopolymerizable composition in an appropriate solvent to form a coating solution, or by applying it to the back surface of the support without a solvent, and then curing and drying it by irradiating it with ultraviolet rays. . After this, it may be further dried by heating if necessary. Examples of the above solvent include water, alcohols such as methanol and ethanol, ethylene glycol monomethyl ether, ethylene glycol monomethyl ether acetate, dimethyl formamide, and cyclohexanone, and one or more of these can be used in combination. .

The surface of the resin layer can be smooth or matte. Further, the resin layer may be a layer that covers the entire back surface of the support, or may have a coated area and an uncoated area (if a coating layer is formed by coating, a coated area and an uncoated area). It may be a form consisting of a regular or irregular pattern with a mixture of.

As the coating method, conventionally known methods such as roll coating, par coating, spray coating, curtain coating, etc. are applied. Further, matte calendar forming methods include, for example, applying the above-mentioned coating liquid using an uneven roll, adding a matting agent to the coating liquid to make it uneven during coating, and applying by spraying the coating liquid. There is a method of forming a matte layer consisting of a coated area and a non-coated area.

Light sources used to cure and dry the coating layer include carbon arc lamps, mercury lamps, xenon lamps, metal halide lamps, fluorescent lamps, and the like.

The thickness of the resin layer of the present invention is preferably 1-100 μm.

The electrophotographic printing original plate of the present invention mainly uses a photoconductive substance (dissolved photoconductive substance) having a solvent that completely dissolves the photoconductive substance used in the photoconductor layer. , and a printing original plate having a photoconductor layer formed by mainly using a pigment-based photoconductive substance that is poorly soluble in a solvent, preparing a photoconductor layer forming liquid by dispersing it, and coating it on a substrate. be done.

A soluble photoconductive substance is mainly used; examples of the original printing plate include the following.

Examples of dissolved photoconductive materials include Japanese Patent Publication No. 37-171
No. 6, No. 38-6961, No. 38-7758, No. 3
No. 9-12703, No. 46-39405, Japanese Unexamined Patent Publication No. 1973
-19509, 5O-1951O, 52-24
No. 37, No. 54-19803, No. 56-66863, No. 56-130766, No. 57-88457, No. 57-161863, No. 58-2854, No. 581
No. 00862, No. 58-118658, No. 59-12
No. 1058, No. 59-121059, No. 59-121
No. 060, No. 59-128559, No. 59-1210
No. 61, No. 59-128560, No. 59-12856
No. 1, No. 59-147355, No. 59-151157
No. 59-152456, No. 59-152457, No. 59-168462, No. 59-168463,
Oxazole compounds, oxadiazole compounds, diphenylmethane compounds, triphenylmethane compounds, anthracene compounds, carbazole compounds, pyrene compounds, and hydrazones described in No. It is also possible to use a sensitizer in combination with the photoconductive substance. Examples of these sensitizers include xanthine dyes such as rose bengal, niosin S1 fluorescein, and phloxine; bromophenol blue bromocresol purple;
Phenolsulfophthalein dyes such as chlorophenolette; triphenylmethane dyes such as Alquazurin 2G, Pontasyl Brilliant Blue-FCF, and Acid Violet 6B; diphenylmethane dyes such as auramine; acridine dyes such as acridine yellow and acridine orange; Rhodamine 810-Damine 6G10-
Rhodamine dyes such as Damin FB, Sulforhodamine B1 Acid Eosin G; Organic carboxylic acids and their anhydrides such as benzoic acid, phthalic acid, maleic acid, hexamaric acid, maleic anhydride, and phthalic anhydride, etc. .

As a binder resin, for example, Japanese Patent Publication No. 37-171
No. 62, No. 38-6961, No. 38-7758, No. 39-12703, No. 46-39405, JP-A-5
No. 0-19509, No. 50-19510, No. 52-2
No. 437, No. 54-19803, No. 56-66863
No. 56-130766, No. 57-88457,
No. 57-161863, No. 58-2854, 5g
-100862, 58-118658, 59-
No. 121058, No. 59-121059, No. 59-1
No. 21060, No. 59-121061, No. 59-12
No. 8559, No. 59-128560, No. 59-128
No. 561, No. 59-147355, No. 59-1511
No. 57, No. 59-152456, No. 59-15245
No. 7, No. 59-168462, No. 59-168463
No. 59-168464, phthalic acid resins, maleic acid resins, acrylic acid resins, crotonic acid resins, and JP-A-54-134632, JP-A-55-1o5.
Although there are alkali-soluble resins such as phenol resins described in No. 254 and the like, relatively poorly alkali-soluble resins can also be used in combination as long as they do not inhibit the removal of the photoconductor layer by an alkaline aqueous solution.

These resins include hydrocarbon polymers such as polystyrene, styrene-butadiene copolymer, and polyisobutylene;
Vinyl resins such as polyvinyl chloride, chlorinated polyethylene, polyvinyl acetate, polyvinyl acetal, polyvinyl butyral, polyvinyl ether; silicone resins; polyamide resins: polyurethane resins; urea resins: melamine resins: polycarbonates: modified or unmodified rosin, parsam Examples include natural resins such as.

The support for the original printing plate of the present invention may be an aluminum plate, a zinc plate, an iron plate whose surface has been treated with chrome plating, or a copper-aluminum plate, a copper-stainless steel plate, a chrome-plated plate, etc.
Copper-aluminum plate, chrome-lead-iron plate, chrome-copper-
Conductive substrates with a hydrophilic surface such as tri-metal plates such as stainless steel plates, paper containing a conductive agent, three-layer plates with a resin layer sandwiched between metal plates such as aluminum, and those with an aluminum layer on at least the surface. , the surface of this aluminum layer is grained, and the centerline average roughness R of the grained surface is
a (according to German standard DIN4768) is 0.2 to 0.
A support having a thickness in the range of 8 μm, having an aluminum layer on at least the surface, the surface of the aluminum layer being grained, then hydrophilized (for example, anodized), and further having a surface sealed. However, it includes a support whose surface has a center line average roughness Ra in a range of 0.2 to 0.8 μm.

Graining of the surface of the aluminum layer includes mechanical polishing methods such as electrolytic polishing or pole polishing in an electrolytic solution such as hydrochloric acid, nitric acid, sulfuric acid, or phosphoric acid, brush polishing, press polishing, honing polishing, etc. . In addition, in the oxide film formation treatment following graining, the amount of oxide film is 10 to 50 m
g/dm" and includes supports further subjected to pore-sealing treatment with hot water, silicate, phosphate, fluorosilicate, etc.

To prepare this type of plate material, the photoconductive substance, binder resin, and sensitizer described above are dissolved in a solvent, and the solution, optionally filtered, is rolled onto the surface-treated support described above. The coating is applied using a coating method such as a coater-wire bar whirler so that the film thickness after drying is about 2 to 10 μm, and then dried.

The above solvents used include diethylamine, dimethylformamide, tetrahydrofuran, cyclohexanone, phenol, cresol, chloroform, dichloroethane, chlorobenzene, dichlorobenzene, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl. Examples of solvents include ether, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, dioxane, and the like alone or in combination of two or more.

Examples of printing original plates mainly using photoconductive pigments as photoconductive substances include the following.

As photoconductive pigments, Japanese Patent Publication Nos. 40-2780 and 44
-12671, 46-30035, 44-16
No. 474, No. 48-30513, No. 50-7434, JP-A-47-18543, No. 47-18544,
No. 47-30330, No. 47-37543, No. 49
-11136, 49-99142, 51-10
No. 9841, No. 54-134632, No. 55-117
No. 15, No. 55-105254, No. 55-15394
No. 8, No. 55-161250, No. 56-1944,
No. 56-2352, No. 56-9752, No. 56-1
No. 9063, No. 56-29250, No. 56-6964
No. 4, No. 56-80050, No. 59-12575.1
No. 59-176756, No. 60-17751.
, No. 60-17752, No. 60-17753, No. 6
No. 0-17754, No. 60-17755, No. 6Q-1
No. 7756, No. 60-17757, No. 60-1775
No. 8, No. 6017759, No. 60-17760, No. 60-17761, No. 6017762, No. 60-3
No. 5750, No. 61-67869, No. 61-6787
There are photoconductive pigments such as perylene pigments, quinacridone pigments, bisbenzimidazole pigments, aromatic polycondensed ring compounds, monoazo pigments, disazo pigments, trisazo pigments, metal or metal-free phthalocyanine pigments, and zinc oxide described in No. 0 etc. , these may be used alone or in combination of two or more.

Further, the photoconductive substance includes a photoconductive pigment in combination with a soluble photoconductive substance. Examples of the dissolvable photoconductive substance include the substances listed above for printing original plates mainly using the dissolvable photoconductive substance.

A sensitizer may be used in combination with these photoconductive substances, and examples of the sensitizer include the substances described for printing original plates mainly using the above-mentioned soluble photoconductive substances.

As the binder resin and the support, the materials mentioned above for the printing original plate mainly using the soluble conductive material can be mentioned.

To create this type of printing plate, the photoconductive substance, binder resin, and sensitizer described above are dissolved in a solvent.
The solution, filtered if necessary, is coated on the surface-treated support described above by a coating method such as a roll coater/wire bar coater so that the film thickness after drying is about 2 to 10 μm, and then dried.

Coating solvents include diethylamine, dimethylformamide, tetrahydrofuran, cyclohexanone, phenol, cresol, chloroform, dichloroethane, chlorobenzene, dichlorobenzene, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, and ethylene glycol. Monomethyl ether acetate, ethylene glycol monoethyl ether acetate, dioxane, etc. alone or in combination
A mixed solvent of more than one species can be mentioned.

In the present invention, when the support is made of metal and/or when the photoconductor layer is a photoconductor layer using a pigment-type photoconductive substance, the photoconductor layer is more likely to be damaged by the back surface of the support. The resin layer of the invention has a great scratch prevention effect.

〔Example〕

Hereinafter, the present invention will be specifically explained with reference to Examples.

Example 1 After degreasing a coiled 2S aluminum plate with a height of 0.25 m+a, it was heated at 30°C in a 0.3 mol/a nitric acid aqueous solution.
Electrolytic polishing surface roughening treatment was performed for 30 seconds at an alternating current and an electrolytic density of 50 A/da'. Next, in a 5% caustic soda aqueous solution, 6
Desmut treatment was performed at 0°C for 10 seconds, and further 20%
After anodizing for 1 minute at 20"013 A/d+o" in a sulfuric acid solution, it was washed with water, dried, and grained.
Protective tape #622C (Sekisui Chemical Industry Co., Ltd.) with a thickness of 60 μI was applied to the back side of the grained aluminum plate.
A 1000 m aluminum coil with a grain chamber and laminated on the back side was manufactured by pressing a heated roller (100'o, 0.2 sec) with the aluminum coil (manufactured by the Company). Grain depth Ra of the aluminum grain (German standard) = 0.65 μm 1 Anodic oxidation film amount 27 mt/dm” Next, the following photosensitive liquid A for forming a photoconductor layer was coated with a double roll coater. Tension 13
0 kg (1000 mm width) was applied and dried (90° C., 3 minutes).

The rollers used to route the aluminum plate were 30 chrome plated rollers and 20 rubber rollers (material: SBR).
rubber). The thin film has a concentration of 50 mg/dI11 after drying.
It was 2.

Photosensitive liquid A for forming photoconductor layer A dispersion liquid for forming a photoconductor layer was prepared according to the following procedure.

First, 4 parts by weight of an alkali-soluble resin having the following structural formula was dissolved in 20 parts by weight of ethylene glycol monomethyl ether, and then filtered through filter paper.

Average molecular weight: approximately 2000 Add ε-type copper 7-silocyanine (manufactured by Toyo Ink Co., Ltd., L) to this solution.
After adding 1 part by weight of iophoton-EK), the mixture was dispersed for 30 minutes using glass beads to prepare a dispersion.

Next, the above electrophotographic printing original plate was cut into a length of 800 cm using a rotary force of 7 mm, and the cut sheets were packaged in bundles of 50 sheets.

Next, the wire bundle was cut into a size of 400 mm x 500 mm, but no blade loss occurred even after cutting more than 50,000 times.

Next, the printing original plate was subjected to plate making using an electrophotographic plate making machine to obtain a lithographic printing plate. When the printing plate was observed, scratches and scratches that were commonly seen in the resist area or the grain area were not found.

The same was true for the back side.

Furthermore, when the printing plate was attached to a printing machine and printed, a large number of good prints were obtained without the can-shaped poor inkling and stains in the can-shaped non-image areas that were commonly seen in the past. .

Comparative Example 1 Instead of adhering the protecting tape #622C to the back side of the grained aluminum plate of Example 1, a tape of the same material with a thickness of 150 μm was overlaid and evaluated in the same manner as in Example 1. I did it. As a result, the polymer base adhered during cutting after about 30,000 sheets, causing trouble. At the same time, the blade was chipped. Furthermore, in printing, it was not possible to obtain a product with satisfactory finish quality. Particularly in color printing, color misregistration occurred.

Comparative Example 2 After carrying out the electrolytic polishing and graining treatment in the same manner as in Example 1, the photosensitive liquid was applied and dried in the same manner as in Example 1 without laminating the protective tape on the back surface of the aluminum plate. 2 times every 100m on the surface coated with the photosensitive layer.
When observing a total of 20 sheets, one by one, there were 100 to 2 dot-shaped scratches of about 5 to 20 μm on the widthwise edge of the aluminum plate.
00 pieces/err 2, width 2~5 a! Is length l-
20 to 30 streak-like scratches of 3 cm were observed/m2. In particular, streak-like scratches were easily observed visually.

Example 2 Instead of the electrolytic polishing surface roughening treatment in a nitric acid aqueous solution in Example 1, a nylon brush was used to roughen the grained area -r bnm/
-/ -y -y XW III body'l fw-F
r-w? -1? A) I-size Chusuke Anodization and lamination were carried out in the same manner as in Example 1.

The grain depth Ra of the aluminum grain was 0.66 μm, and the amount of anodic oxide film was 26.5a+g/dm''.

Next, a photosensitive liquid was applied and dried in the same manner as in Example 1. Observations were made in the same manner as in Comparative Example 2, but no can-shaped objects were observed.

Comparative Example 4 An original plate for electrophotographic printing was produced in the same manner as in Example 2, except that the protective tape was not laminated on the back side of the aluminum plate in Example 2. Similar to Comparative Example 2, when observing the surface coated with the photosensitive layer, it was found that there were about 5 to 20 dot-like scratches at the edges in the width direction of the aluminum plate, 30 to 60 scratches/L112, and a width of 2 to 5 μm1. Length 1~
5 to 10 3 cm streak-like scratches/m2 were observed.

Example 3 Example 1) IF except that the following photosensitive liquid B was used instead of photosensitive liquid A for forming a photoconductor layer in Example 1.
m1. - I-f lk * 75 Where do you go? - An organic photoconductive substance having the following structural formula, a binder, and a sensitizer were dissolved in the following solvent to prepare a photosensitive liquid for forming a photoconductor layer.

Rhodamine-B 0.04 parts by weight 1.
2-Dichloroethane: Ethylene glycol monomethyl ether- Cutting was carried out in the same manner as in Example 1 to a size of 400 m+a x 50 G+ am, but no chipping occurred even after cutting over 50,000 times. Further, when the coated surface of the photosensitive layer was observed, no scratches or the like were found.

Example 4 In place of the protective tape #622C in Example 1, vinyl chloride copolymer “VinyliteVYNS” was used.
The test was carried out in the same manner as in Example 1, except that a cyclohexanone solution (20% by weight) of -3'' (manufactured by Bakelite) was applied using a double roll coater and dried. (The thickness of the resin layer was 20 μm. ) As a result, Example 1
Similar good results were obtained.

Example 5 Vinyl chloride copolymer “Vinyl” was used as the back coat layer.
It was carried out in the same manner as in Example 4, except that a solution in which copper powder with a solid content ratio of IQvL/wt% was mixed and dispersed in a 20wt/wt% cyclohexanone solution of ``ite VYNS-3'' (manufactured by Bakelite) was used. An original plate for electrophotographic printing of Example 5 was created (the thickness of the back coat layer was 30 μm).
). This printing original plate was tested in the same manner as in Example 1, and as a result, similar to Example 1, good results were obtained.

Example 6 A printing original plate was prepared in the same manner as in Example 5 except that 3Qwt/wt% carbon black was used instead of copper powder, and as a result of evaluation, good results were obtained as in Example 5. Ta.

Example 7 Vinyl chloride copolymer Vinylite VYNS
3 (manufactured by Bakelite) instead of styrene-maleic anhydride resin “Scripset 520” (
A printing original plate was prepared and evaluated in the same manner as in Example 4, except that E1 Monsando was used. As a result, the same good results as in Example 5 were obtained.

Example 8 A printing original plate was prepared and evaluated in the same manner as in Example 4 except that poly(sodium styrene butyl methacrylate-butyl acrylate-methacrylic acid) was used as the resin for the back coat layer, and good results were obtained. Obtained.

Example 9 A printing original plate was prepared and evaluated in the same manner as in Example 4 except that poly(sodium styrene sulfonate) was used as the resin for the back coat layer. Example 1O A printing original plate was prepared in the same manner as in Example 4 except that poly(dimethyldiallylammonium chloride) was used as the resin for the back coat layer, and when evaluated, good results were obtained. .

Example 11 The back coat layer was made of the Vinilite VYNS
A printing original plate was prepared and evaluated in the same manner as in Example 5, except that a layer (thickness: 30 μm) in which SnO□ with a solid content ratio of 10 vt/wt% was dispersed in 3 was used, and good results were obtained. Obtained.

Example 12 A back coat layer was added to the resin of Example 8 at 30 wt/vt%.
A printing original plate was prepared and evaluated in the same manner as in Example 5, except that it was a layer in which carbon black was dispersed.
Good results were obtained.

Example 13 A back coat layer was added to the resin of Example 9 at 10vt/wt%.
Example 5 and lashing 7 except that the layer had copper powder dispersed in it.
L-choin Sarada Wataka is in the works! ．． Good results were obtained for 1 person.

Example 14 A back coat layer was added to the resin of Example 10 at 10 wt/it.
A printing original plate was prepared and evaluated in the same manner as in Example 5, except that the layer had % of SnO dispersed therein, and good results were obtained.

In addition, in the electrophotographic original plates of Examples 1 to 4,
When the plates were deposited, a small amount of dust, which was thought to be transferred from the upper back coat layer to the surface of the photoconductor layer of the next plate, was observed, but in Examples 5 to 14, this was not observed. Ta. Of course, I couldn't see any scratches.

〔Effect of the invention〕

According to the present invention, since the support surface opposite to the photoconductor layer is coated with a resin layer that is softer than the support surface, photoconductor particles generated when the photoconductor layer surface and the back surface are handled so as to come into contact with each other. An original plate for electrophotographic printing is provided in which the occurrence of image defects due to layer scratches is improved.

Claims (1)

[Claims] An original plate for electrophotographic printing in which a printing plate is obtained by removing the photoconductor layer in the non-image area after toner image formation, and is characterized in that a resin layer is provided on the opposite side of the photoconductor layer with a support in between. Original plate for electrophotographic printing.