JPH0690544B2 - Electrophotographic lithographic printing plate - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an electrophotographic lithographic printing plate precursor prepared by an electrophotographic method, and more particularly to a binder for forming a photoconductive layer of the lithographic printing plate precursor. Regarding improvement of resin.

(Prior Art) At present, various kinds of offset original plates for direct plate making have been proposed and put into practical use. Among them, photoconductive particles such as zinc oxide and a binder resin are mainly contained on a conductive support. In the photoconductor provided with the photoconductive layer described above, a highly lipophilic toner image is formed on the surface of the photoconductor through a normal electrophotographic process, and then the surface is treated with a desensitizing liquid called an etching liquid. A technique for obtaining an offset original plate by selectively making a non-image portion hydrophilic is widely used.

In order to obtain a good printed matter, first, the original image is faithfully copied to the offset original plate, and at the same time, the surface of the photoconductor is easily made compatible with the desensitizing solution and the non-image area is made sufficiently hydrophilic, and at the same time, the water resistance is improved. In addition, in printing, the photoconductive layer with the image does not come off, it is well compatible with fountain solution, and the hydrophilicity of the non-image area is sufficient so that stains do not occur even when the number of printed sheets increases. Needs to be retained.

It is already known that the ratio of zinc oxide to the binder resin in the photoconductive layer affects these performances. For example, if the ratio of the binder resin to the zinc oxide particles of the photoconductive layer is reduced, the desensitizing property of the photoconductive layer surface is improved and the background stain is reduced, but on the other hand, the internal cohesive force of the photoconductive layer itself is reduced. Is reduced,
Printing durability is reduced due to insufficient mechanical strength. On the contrary, if the ratio of the binder resin is increased, the printing durability is improved, but the background stain is increased. Needless to say, the background stain is a phenomenon related to the quality of the desensitizing property of the surface of the photoconductive layer, but the desensitizing property of the surface of the photoconductive layer is a phenomenon of the zinc oxide and the binder resin in the photoconductive layer. It has become clear that not only depends on the ratio, but also on the type of binder resin.

Known resins such as silicone resin (Japanese Patent Publication No. 34-6670) and styrene-butadiene resin (Japanese Patent Publication No. 35-35
1960), alkyd resin, maleic acid resin, polyamide (JP-B-35-11219), vinyl acetate resin (JP-B-41-242)
5), vinyl acetate copolymer (JP-B 41-2426), acrylic resin (JP-B 35-11216), acrylic ester copolymer (eg JP-B 35-11219, JP-B 36-8510, JP-B 41- 13
946 etc.) are known. However, in electrophotographic photosensitive materials using these resins, 1) the photoconductive layer has a low charging property, 2) the quality of the image portion of the copied image (particularly halftone dot reproducibility / resolution) is poor, and 3) exposure. Low sensitivity, 4) Desensitization is not sufficiently performed even when desensitized for use as an offset master, and thus causes stains on printed matter when offset printing is performed. 5) Film strength of photosensitive layer Is insufficient, and the offset printing causes the photosensitive layer to be detached, and the number of printed sheets cannot be increased. 6) The image quality is easily affected by the environment (for example, high temperature and high humidity) at the time of making a copy image. There was a problem.

In particular, as the offset original plate, as described above, the occurrence of scumming due to insufficient desensitizing property is a big problem, and in order to improve this, various development of zinc oxide binding resin for improving desensitizing property has been studied. Is coming. For example, Japanese Examined Shokoku 50-3
In 1011, w1.8 to 10 × 10 ⁴ obtained by copolymerizing a (meth) acrylate-based monomer with another monomer in the presence of fumaric acid.
In which a resin having a Tg of 10 to 80 ° C. and a copolymer composed of a (meth) acrylate-based monomer and a monomer other than fumaric acid are used in combination. In JP-A-53-54027, at least a carboxylic acid group is formed from an ester bond. A method using a terpolymer containing a (meth) acrylic acid ester having a substituent having 7 atoms apart, JP-A-54-20735 and JP-A-57-202544 discloses acrylic acid and hydroxyethyl (meth). ) Using quaternary or quaternary copolymers containing acrylates
In 58-68046, one using a terpolymer containing a (meth) acrylic acid ester having an alkyl group having 6 to 12 carbon atoms as a substituent and a vinyl monomer containing a carboxylic acid is a desensitizing agent for the photoconductive layer. It is described that it is effective in improving sex.

(Problems to be Solved by the Invention) However, even with the above-mentioned resin that is said to be effective in improving the desensitizing property, it is still satisfactory in the background stain and the printing durability when actually evaluated. Not a thing.

The present invention solves the problems of the conventional electrophotographic lithographic printing plate precursor as described above.

An object of the present invention is to reproduce a copy image faithful to an original image, and to produce not only a uniform background stain on the entire surface as an offset original plate but also a spot-like background stain, which is excellent in desensitizing lithographic printing. It is to provide the original version.

Another object of the present invention is to provide a lithographic printing plate having high printing durability, in which the hydrophilicity of the non-image area is sufficiently maintained and scumming does not occur even when the number of printed sheets is increased during printing. .

Another object of the present invention is to provide a lithographic printing plate which has a clear and high-quality image even when the environment changes during the plate-making process, such as low temperature and low humidity or high temperature and high humidity, and does not cause background stain.

A further object of the present invention is to provide a lithographic printing plate having excellent preservability of the photographic material before processing.

(Means for Solving the Problems) The above-mentioned various objects are provided by providing a photoconductive layer formed by containing at least one layer of photoconductive zinc oxide and a binder resin on a conductive support. In the lithographic printing plate precursor using a photographic photoreceptor, the binder resin is represented by the general formula [-OL].
This is achieved by an electrophotographic lithographic printing original plate comprising at least one resin containing at least one functional group selected from the group

In the general formula [-OL], L is _{-CO-Y 1, -CO-Z} -Y 2, -CH = CH-CH 3, Represents

However, R ₁ , R ₂ and R _{3, which} may be the same or different, each represents a hydrogen atom, a hydrocarbon group or —O—R ′ (R ′ represents a hydrocarbon group), and Y ₁ , Y ₂ represents a hydrocarbon group, Z represents an oxygen atom, a sulfur atom or a —NH— group, and X represents a sulfur atom or an oxygen atom.

The functional group of the general formula [-OL] produces a hydroxyl group by decomposition, and will be described in more detail below.

L is In the case of representing, R ₁ , R ₂ and R ₃ may be the same or different from each other, preferably a hydrogen atom and an optionally substituted linear or branched alkyl group having 1 to 18 carbon atoms ( For example, methyl group, ethyl group, propyl group, butyl group, hexyl group, octyl group, decyl group, dodecyl group, octadecyl group, chloroethyl group, methoxyethyl group, methoxypropyl group, etc.), alicyclic which may be substituted Group (eg cyclopentyl group, cyclohexyl group, etc.), optionally substituted aralkyl group having 7 to 12 carbon atoms (eg benzyl group, phenethyl group, chlorobenzyl group, methoxybenzyl group, etc.) or optionally substituted Aromatic groups (eg phenyl, naphthyl, chlorophenyl, tolyl,
Methoxyphenyl group, methoxycarbonylphenyl group,
A dichlorophenyl group or the like) or -OR '(R' represents a carbon-hydrogen group, specifically, the same substituents as the hydrocarbon group of R ₁ , R ₂ and R ₃ ) Represents

When L represents —CO—Y ₁ , Y ₁ is preferably an optionally substituted linear or branched alkyl group having 1 to 6 carbon atoms (for example, methyl group, trichloromethyl group, trifluoromethyl group, Methoxymethyl group, phenoxymethyl group, 2,2,2-trifluoroethyl group, t-butyl group, hexafluoro-i-propyl group, etc., optionally substituted aralkyl group having 7 to 9 carbon atoms (eg, benzyl group) , A phenethyl group, a methylbenzyl group, a trimethylbenzyl group, a heptamethylbenzyl group, a methoxybenzyl group, and the like, and an optionally substituted aryl group having 6 to 12 carbon atoms (for example, a phenyl group, a nitrophenyl group, a cyanophenyl group, a methanesulfonyl group). Phenyl group, methoxyphenyl group, butoxyphenyl group, chlorophenyl group, dichlorophenyl group, trifluoromethylphenyl group Representing the etc.).

In the case where L represents -CO-Z-Y _2, Z represents an oxygen atom, a sulfur atom or an -NH- bond group, Y ₂ is the same meaning as Y ₁ described above.

Further L When X is represented, X represents an oxygen atom or a sulfur atom.

The resin containing at least one functional group selected from the group of the general formula [-O-L] used in the present invention has a hydroxyl group contained in the polymer, and the hydroxyl group contained in the polymer is represented by the general formula [- A method of converting it into a functional group of -OL], or containing one or more functional groups of the general formula [-OL],
It is produced by a method of polymerizing one or more kinds of monomers or a polymerization reaction of the monomers and other monomers copolymerizable therewith.

For example, Yoshio Iwakura
Production methods in which the hydroxyl group of a monomer is converted into a functional group of the general formula [-OL], such as known literatures such as "Reactive Polymer", page 158 (published by Kodansha) by Keisuke Kurita, etc. As described in detail, each is described in the publicly known references and the like of the review references such as "New Experimental Chemistry Course, Volume 14, Synthesis and Reactions of Organic Compounds [V] page 2497 (published by Maruzen Co., Ltd.) edited by The Chemical Society of Japan. It can be manufactured according to the method.

The polymer contains a functional group of the general formula [-OL] in advance for the reason that the functional group of the general formula [-OL] in the polymer can be arbitrarily adjusted or that impurities are not mixed. A method of producing by a polymerization reaction from a monomer is preferable. Specifically, a compound containing a polymerizable double bond and containing at least one hydroxyl group can be prepared by converting a hydroxyl group into a compound represented by the general formula [- O-L] or by reacting a compound containing a functional group of the general formula [-O-L] with a compound containing a polymerizable double bond,
It can be manufactured.

As described above, the monomer containing a functional group of the general formula [-OL] used in the method for producing a desired resin by the polymerization reaction will be more specifically described. Compounds such as However, the examples are not limited to these compounds.

General formula (II) In the formula (II), X'is -O-, -CO-, -COO-, -OCO.
-, Indicates an aromatic group or a heterocyclic group (provided that Q ₁ , Q ₂ , Q ₃ ,
Q ₄ each represents a hydrogen atom, a hydrocarbon group, or Y′-OL in the formula (II)], b ₁ and b ₂ may be the same or different, and a hydrogen atom or a hydrocarbon group Or Y'-OL in the formula (II), and n is an integer of 0-18].

Y ′ connects the bonding group X ′ and the bonding group [—OL],
Represents a carbon-carbon bond which may be passed through a hetero atom (as a hetero atom, an oxygen atom, a sulfur atom or a nitrogen atom is shown), for example, -SO ₂ NH-, -NHCOO-, -NHCONH-, etc. are composed of a single or a combination of bonding units (provided that b ₃ , b ₄ ,
b ₅ has the same meaning as b ₁ and b ₂ above).

L has the same meaning as in formula (I).

a ₁ and a ₂ may be the same or different, and are a hydrogen atom, a hydrocarbon group (for example, an alkyl group having 1 to 12 carbon atoms which may be substituted with —COOH or the like), —COOH or —COO— W
(W represents an alkyl group having 1 to 18 carbon atoms, an alkenyl group, an aralkyl group, an alicyclic group or an aromatic group which may be substituted with a substituent containing a general formula (-OL) group) Represents

More specifically, examples of the compound having the functional group of the general formula [-OL] include the following compounds, but the scope of the present invention is not limited thereto. .

(However, Me represents a methyl group) These monomers may be polymerized alone, or,
You may make it a copolymer by combining with the other monomer which can be copolymerized with these monomers. Other monomers to be copolymerized include, for example, vinyl acetate, vinyl propionate, vinyl butyrate, allyl acetate, allyl propionate, and other aliphatic vinyl carboxylates or allyl esters, acrylic acid, methacrylic acid, crotonic acid. , Esters or amides of unsaturated carboxylic acids such as itaconic acid, maleic acid and fumaric acid, styrene derivatives such as styrene, vinyltoluene and α-methylstyrene, α-olefins, acrylonitrile, methacrylonitrile, N-vinyl Examples thereof include vinyl group-substituted heterocyclic compounds such as pyrrolidone.

In the case of a copolymer having a functional group-containing monomer of the general formula [-O-L] of the present invention as a copolymer component, the copolymer component is 99.5 to 0.5% by weight based on the whole polymer. %, Preferably 99
Up to 1% by weight. The molecular weight of the polymer is 10 ³ to 10 ⁶ , preferably 5 × 10 ^{3 to} 5 × 10 ⁵ .

Conventionally known resins can be used together with the resin used in the present invention. For example, the above-mentioned silicone resin, alkyd resin, vinyl acetate resin, polyester resin, styrene-butadiene resin, acrylic resin and the like can be mentioned. Specifically, Ryuji Kurita and Jiro Ishiwatari, Polymer, No. 17
Volume, p. 278 (1968), Harumi Miyamoto, Hidehiko Takei, Imaging, 1973 (NO.8) p. 9, etc.

The resin to be used in the present invention and a known resin can be mixed at an arbitrary ratio, but the resin represented by the general formula [-O-
The content of the functional group component of L] must be 1 to 80% by weight, preferably 5 to 40% by weight.

When the content of the functional group component of the general formula [-OL] in the total amount of resin is less than 1% by weight, the obtained lithographic printing plate precursor is
The hydrophilicity produced by the desensitizing treatment with the desensitizing liquid / fountain solution is not sufficient, and stains are generated during printing.

On the other hand, if it is more than 80% by weight, the image formability at the time of copying is not good, and the coating strength of the photoconductive layer at the time of printing is weakened and the durability is deteriorated.

The resin containing at least one functional group selected from the group of the general formula [-OL] according to the present invention is a hydroxyl group obtained by hydrolysis or hydrogenolysis with a desensitizing solution or a fountain solution used at the time of printing. Is a resin that produces.

Therefore, when the resin is used as a binder resin for a lithographic printing plate precursor, the hydrophilicity of the non-image area which is hydrophilized by the desensitizing liquid is due to the hydroxyl group generated in the resin.
Since it is further enhanced, the lipophilicity of the image area and the hydrophilicity of the non-image area become clear, and printing ink is prevented from adhering to the non-image area during printing. As a result, it becomes possible to print a large number of clear printed matter with clear image quality, compared with the conventional lithographic original plate using a resin.

When the conventional resin containing the hydroxyl group itself is used from the beginning, the viscosity of the dispersion of zinc oxide and the binder resin becomes high, and even if it is applied, the smoothness of the photoconductive layer is significantly deteriorated, and the film The strength was not sufficient, and the electrophotographic characteristics were not satisfactory. Even if an original plate having sufficient smoothness could be produced, stains were generated during printing. Furthermore,
Even if a master plate with good image quality of the copied image and printed matter is prepared by adjusting the hydroxyl groups in the resin, the environment is low temperature / low humidity or high temperature / high humidity during the creation of the copied image (plate making process). In particular (at high temperature and high humidity), the image quality of the copied image deteriorated due to the occurrence of background fog, a decrease in density of the image portion, occurrence of fine lines / character skips, and the like.

These things are because the interaction between the hydroxyl group in the binder resin and the photoconductive zinc oxide particle surface is strong, so that the resin adsorption amount on the particle surface increases, and as a result, the desensitizing solution or fountain solution Even if the familiarity is impaired or the hydroxyl groups in the binder resin can be adjusted appropriately to the zinc oxide particles, the hydrophilic atmosphere at the interface between the hydroxyl groups in the resin and the zinc oxide particles Is significantly changed when exposed to low temperature / low humidity or high temperature / high humidity, and it is presumed that electrophotographic characteristics such as surface potential and dark decay after charging are deteriorated.

The lithographic printing plate precursor of the present invention is used at a ratio of 10 to 60 parts by weight, preferably 15 to 30 parts by weight, of the binder resin described above with respect to 100 parts by weight of photoconductive zinc, and if necessary, Various known additives for electrophotographic photosensitive layers such as sensitizing dyes such as xanthene dyes and cyanine dyes (eg rose bengal) or chemical sensitizers such as acid anhydrides can be used in combination. (For example, Harumi Miyamoto, Hidehiko Takei, Imaging, 1973 (NO.8), page 12, etc.) The amount added is 0.0005 to 2.0 parts by weight with respect to 100 parts by weight of the photoconductor.

The photoconductive layer according to the present invention can be provided on a conventionally known support. Generally speaking, the support of the electrophotographic photosensitive layer is preferably conductive, and as the conductive support, the substrate such as metal, iron or plastic sheet is impregnated with a low resistance substance as in the conventional case. Those which have been subjected to a conductive treatment by, for example, those which are coated with at least one layer for the purpose of imparting conductivity to the back surface of the substrate (the surface opposite to the surface on which the photosensitive layer is provided), and for preventing curling, Having a water-resistant adhesive layer on its surface, having at least one precoat layer provided on the surface layer of the support as required, and laminating a substrate plastic which is vapor-deposited with Al or the like on paper Etc. can be used.

Specifically, as an example of a conductive substrate or a conductive material,
Yukio Sakamoto, Electrophotography, 54 (NO.1) 2-11 (1975),
Hiroyuki Moriga, "Introduction to Special Paper Chemistry" Polymer Publishing Association (197
5), MF Hoover, J. Macromol. Sci. Chem. A-4 (6), No.
Those described on pages 1327 to 1417 (1970) and the like can be used.

(Examples) The embodiments of the present invention will be illustrated below, but the contents of the present invention are not limited thereto.

Example-1 and Comparative Examples A to C 36 g of n-butyl methacrylate, ethyl methacrylate 5
A mixed solution of 4 g, the compound 10 g of the compound example (2) and toluene 200 g was heated to a temperature of 70 ° C. under a nitrogen stream, 10 g of azobisisobutyronitrile (AIBN) was added, and the mixture was reacted for 8 hours. The weight average molecular weight of the obtained copolymer was 65,000. Subsequently, 30 g of this copolymer as a solid content and 10 g of (butyl methacrylate / acrylic acid (98/2) weight ratio) copolymer (weight average molecular weight 45000), zinc oxide 200 g, rose bengal 0.05 g, phthalic anhydride 0.01 g and toluene 300g
The mixture was dispersed in a ball mill for 2 hours to prepare a photosensitive layer-forming product, which was dried to a conductive paper to give a dry adhesion amount of 25 g /
An electrophotographic light-sensitive material was prepared by applying a wire bar so as to give m ² and drying at 110 ° C. for 1 minute, and then leaving it in the dark at 20 ° C. and 65% RH for 24 hours.

In the above Production Example, three kinds of comparative photosensitive materials A, B and C were prepared by replacing the photosensitive layer forming material with the following copolymers.

Comparative photosensitive material A; n-butyl methacrylate 40 g, ethyl methacrylate 6
A copolymer was synthesized under the same conditions as in Example 1 except that a mixed solution of 0 g and 200 g of toluene was used. The weight average molecular weight of the obtained copolymer was 65,000. A light-sensitive material was prepared in the same manner as in Example 1.

Comparative photosensitive material B; n-butyl methacrylate 36 g, ethyl methacrylate 5
A copolymer was synthesized in the same manner as in Example 1 except that a mixed solution of 4 g, 10 g of 2-hydroxyethyl methacrylate and 200 g of toluene was used. The weight average molecular weight of the obtained copolymer was 63,000. A light-sensitive material was prepared in the same manner as in Example 1.

Comparative photosensitive material C; n-butyl methacrylate 30 g, ethyl methacrylate 4
A copolymer was synthesized in the same manner as in Example 1 except that a mixed solution of 5 g, 25 g of 2-hydroxyethyl methacrylate and 200 g of toluene was used. The weight average molecular weight of the obtained copolymer was 61,000. A light-sensitive material was prepared in the same manner as in Example 1.

The film properties (surface smoothness), electrostatic properties, desensitizing property of the photoconductive layer (expressed by the contact angle of water of the photoconductive layer after desensitizing treatment) and printability of these photosensitive materials were examined. It was Printability is fully automatic plate-making machine ELP404V (Fuji Photo Film Co., Ltd.)
Made by using the developer ELP-T as an exposure and development treatment to form an image, and using a desensitizing solution ELP-E for etching with an etching processor. (Note that the printing machine used was a Hamada Star 800SX type manufactured by Hamada Star Co., Ltd.).

The above results are summarized in Table-1.

Embodiments of the evaluation items shown in Table 1 are as follows.

Note 1) Smoothness of photoconductive layer: The obtained photosensitive material was measured for smoothness (sec / cc) under a condition of an air capacity of 1 cc using a Bek smoothness tester (manufactured by Kumagai Riko Co., Ltd.). It was measured.

Note 2) Electrostatic characteristics: Paper analyzer (Paper Analyzer SP manufactured by Kawaguchi Electric Co., Ltd.) on each photosensitive material in a dark room at a temperature of 20 ° C and 65% RH.
-428 type) and after corona discharge for 20 seconds at -6KV
Let stand for 10 seconds, measure the surface potential Vo at this time, then irradiate the photoconductive layer surface with visible light with an illuminance of 2.0 lux, determine the time until the surface potential Vo decays to 1/10, and then calculate the exposure amount. Calculate E1 / 10 (lux seconds).

Note 3) Contact angle with water: Each photosensitive material is passed through an etching processor once using a desensitizing solution ELP-E (manufactured by Fuji Photo Film Co., Ltd.) to desensitize the photoconductive layer surface. After the treatment, a drop of distilled water (2 μl) is placed on this, and the contact angle with the water formed is measured with a goniometer.

Note 4) Image quality of copied image: Each photosensitive material and fully automatic plate-making machine ELP404V (manufactured by Fuji Photo Film Co., Ltd.) are left at room temperature and humidity (20 ° C, 65%) for one day, and then plate-made to make a copied image. And an image (fog, image quality) of the obtained copy original plate is visually observed (this is referred to as I). The image quality II of the copied image is tested in the same manner as in I above, except that the plate making is performed at high temperature and high humidity (30 ° C., 80%).

Note 5) Background stain of printed matter: Each photosensitive material is subjected to plate-making with a fully automatic plate-making machine ELP404V (manufactured by Fuji Photo Film Co., Ltd.) to form a toner image, and desensitized under the same conditions as Note 3) above. This is used as an offset master in an offset printer (Hamaduster 800SX type manufactured by Hamada Star Co., Ltd.) to print 500 sheets on high-quality paper, and the background stain of all prints is visually judged. This is designated as background stain I of the printed matter.

For the background stain II of the printed matter, the desensitizing solution is diluted 5 times,
In addition, the test is performed in the same manner as the background stain I, except that the dampening water at the time of printing is diluted twice.

The case of II corresponds to printing under a stricter condition than I.

The copied images obtained using the light-sensitive materials of the present invention and Comparative Examples A and B were both clear images, and those of Comparative Example C had a significantly deteriorated smoothness of the photoconductive layer surface and non-image areas. There was a lot of fog and the image quality was not clear. In addition, each of the photosensitive materials was subjected to plate making in an environment of (30 ° C., 80%), Comparative Examples B and C
, The copied image was remarkably deteriorated (background fog was generated and the image density was 0.6 or less).

Further, the contact angle of each of the light-sensitive materials subjected to the desensitizing treatment with the desensitizing solution with water was small, at 15 ° C. or less, for the materials of the present invention and Comparative Example B, indicating that they were sufficiently hydrophilicized. It was

Further, when these were printed as offset master plates, only the plates of the present invention and Comparative Example B were the good ones which did not cause background stains in the non-image area.
Further, both the plates had good image quality of the printed matter even after printing 10,000 sheets and did not cause scumming, but the plates of Comparative Examples A and C caused scumming.

From the above facts, only the light-sensitive material of the present invention was able to obtain 10,000 or more prints which always form a clear copy image and are free from background stain even when the plate is made under changing environmental conditions.

Example 2 Benzyl methacrylate 30 g, ethyl methacrylate 45
g, a mixed solution of 25 g of the compound of Example (6) and 200 g of toluene was heated to a temperature of 75 ° C. under a nitrogen stream, and then AIBN1.
5 g was added and reacted for 8 hours. The weight average molecular weight of the obtained copolymer was 43,000.

Other than that was operated under the same conditions as in Example 1 to prepare a light-sensitive material. This is a fully automatic plate-making machine as in Example 1.
After making a plate with ELP404V, the density of the obtained master plate for offset printing was 1.2 or more, and the image quality was clear.
Furthermore, when an etching treatment was performed and printing was performed by a printing machine, the printed matter after printing 10,000 sheets had no fog in the non-image area and the image was clear.

Further, this photosensitive material was allowed to stand for one year and then subjected to the same treatment as above, but there was no change from before the passage of time.

Example 3 16 g of styrene, 64 g of ethyl methacrylate, 20 g of the compound of compound example (7), 0.2 g of acrylic acid and 200 g of toluene
After heating the mixed solution of above under a nitrogen stream to a temperature of 75 ° C, AI
BN1.0g was added and it reacted for 8 hours. The obtained copolymer had a molecular weight of 55,000. 40 g of the solid content of this copolymer was taken, and the same mixture of zinc oxide, rose bengal, phthalic anhydride, and toluene as in Example 1 was used,
A light-sensitive material was prepared in the same manner as in Example 1.

When a plate was prepared using the same apparatus as in Example 1, the density of the obtained master plate for offset printing was 1.0 or more, and the image quality was clear. Further, after etching treatment and printing with a printing machine, the printed matter after printing 10,000 sheets had a clear image quality without fog.

Further, this photosensitive material was allowed to stand for one year and then subjected to the same processing as above, but it was completely the same as before the passage of time.

(Effects of the Invention) From the above results, the lithographic printing plate precursor according to the present invention reproduces a copy image faithful to the original image and has good hydrophilicity in the non-image area, so that no background stain occurs and light It is clear that the smoothness and electrostatic properties of the conductive layer are good and the printing durability is excellent.

Furthermore, the original plate for this planographic printing plate is not affected by the environment during plate making,
Further, the storability of the light-sensitive material before processing is excellent.

Claims (1)

[Claims] 1. A lithographic printing plate precursor using an electrophotographic photoreceptor comprising a photoconductive layer comprising at least one layer of photoconductive zinc oxide and a binder resin on a conductive support. In the electrophotographic planographic printing plate, the binder resin contains at least one kind of resin containing at least one kind of functional group selected from the group of the general formula [-OL] in a side chain. Original plate for printing. In the general formula [-OL], L is _{-CO-Y 1, -CO-Z} -Y 2, -CH = CH-CH 3, Represents However, R ₁ , R ₂ and R _{3, which} may be the same or different, each represents a hydrogen atom, a hydrocarbon group or —O—R ′ (R ′ represents a hydrocarbon group), and Y ₁ , Y ₂ represents a hydrocarbon group, Z represents an oxygen atom, a sulfur atom or a —NH— group, and X represents a sulfur atom or an oxygen atom.