JPH0625864B2 - Method of manufacturing lithographic printing original plate - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a lithographic printing plate that uses a lithographic printing plate precursor (hereinafter abbreviated as PS plate) and can be easily processed.

[Prior Art] A PS plate having a photosensitive layer formed by coating a composition containing silver halide and a vinyl compound on an aluminum support is disclosed in, for example, JP-A-57-212146.
It is disclosed in Japanese Patent Laid-Open No. 58-16231.
The method for producing a lithographic printing plate from this PS plate comprises the following steps. That is, a step of exposing the PS plate to a pattern (exposure step), a step of immersing the PS plate in a developing solution, washing with water to elute the photosensitive layer in the unexposed area (developing step), and a step of removing the photosensitive layer It comprises a step of applying gum arabic or the like to the surface of the aluminum support in order to prevent the surface of the aluminum support from being exposed to the air and decreasing its hydrophilicity. The above PS plate has high sensitivity because it utilizes the photosensitivity of silver halide.
As described above, in the developing step, a method of removing the photosensitive layer using a developer, a so-called wet development processing method is used, which not only complicates the manufacturing step, but also causes hygiene and pollution depending on chemicals used. In addition, there were unfavorable points such as safety.

[Object of the Invention] An object of the present invention is to provide a method for producing a lithographic printing plate by a simple method without using a developing solution, that is, without passing through a wet development processing step.

SUMMARY OF THE INVENTION The present invention provides a planographic printing plate comprising a water-resistant support, a microcapsule containing a silver halide, a reducing agent and a polymerizable compound, and a photosensitive layer containing a water-resistant hydrophilic binder. The step of imagewise exposing the printing original plate, the step of heating the lithographic printing original plate to perform heat development to cure the microcapsules, and the step of heating the lithographic printing original plate at a temperature higher than the above-mentioned heat development temperature to obtain microscopic portions of uncured portions A method for producing a lithographic printing plate comprising the steps of softening, fusing, melting or breaking a capsule to form an oleophilic film having ink receptivity.

The present invention also provides a microcapsule containing a silver halide, a reducing agent and a polymerizable compound on a water-resistant support,
The steps of imagewise exposing a lithographic printing plate precursor provided with a photosensitive layer containing a hydrophilic binder and a water-proofing agent, heating the lithographic printing plate precursor to heat development to cure the microcapsules, and lithographic printing plate precursor Characterized in that it comprises a step of heating at a temperature higher than the heat development temperature to soften, fuse, melt or destroy the uncured microcapsules, thereby forming a lipophilic film having ink acceptability. There is a method for producing a lithographic printing plate.

[Effects of the Invention] In the method for producing a printing plate of the present invention, since the core material such as silver halide has the photosensitive layer contained in the microcapsules, after the exposure / heat development (primary heating), heating (second heating) is performed. By the subsequent heating, the photosensitive layer is softened and destroyed in the water-insoluble portion formed by curing in a state where the microcapsules are surrounded by the water-resistant hydrophilic binder and the uncured portion of the capsule. For example, it is easily divided into a portion where the polymerizable compound is eluted. As a result, image areas (ink-accepting areas) and non-image areas (hydrophilic areas) are formed on the photosensitive layer.

That is, after the above heating (secondary heating) treatment, in the portion where uncured microcapsules (capsules in the image area) are present, the capsules are softened, destroyed, etc. A lipophilic film (image area) is formed in close contact with the top.
On the other hand, the hydrophilic binder is used in the area where the microcapsules (capsules in the non-image area) in which the polymerizable compound in the area where the latent image of silver halide is formed (or the area where the latent image is not formed) are polymerized and cured are present. It forms a water-insoluble hydrophilic surface (non-image area) on the surface.

Therefore, according to the production method of the present invention, a lithographic printing plate can be easily obtained after exposure by developing without heating using a developing solution and then by heating and / or pressing.

DETAILED DESCRIPTION OF THE INVENTION A lithographic printing plate precursor (PS plate) used in the present invention comprises a water-resistant support, microcapsules provided thereon, containing a silver halide, a reducing agent and a polymerizable compound, and And a photosensitive layer containing a water resistant hydrophilic binder.

Further, the lithographic printing original plate (PS plate) used in the present invention comprises a water-resistant support and microcapsules provided thereon, containing a silver halide, a reducing agent and a polymerizable compound,
And a photosensitive layer containing a hydrophilic binder and a waterproofing agent.

In the following description, it is composed of a water-resistant support and a photosensitive layer provided thereon, containing a silver halide, a microcapsule containing a reducing agent and a polymerizable compound, and a water-resistant hydrophilic binder. The lithographic printing original plate (PS plate) of the above-mentioned embodiment will be mainly described.

As the silver halide used in the PS plate of the present invention, silver halide known in the photographic art can be used. In the present invention, any grains of silver chloride, silver bromide, silver iodide or silver chlorobromide, silver iodobromide, silver iodobromide and silver chloroiodobromide can be used.

The halogen composition of the silver halide grains may be uniform or non-uniform on the surface and inside. Regarding silver halide grains having multiple structures having different compositions on the surface and inside, JP-A-57-154232 and 58-10853 are known.
No. 3, No. 59-48755, No. 59-52237, U.S. Pat. No. 4,433,048 and European Patent No. 100,984. Further, as used in the light-sensitive material described in Japanese Patent Application No. Sho 61-25576, silver halide grains having a high ratio of silver iodide in the shell portion may be used.

There is also no particular limitation on the crystal habit of the silver halide grains. For example, lithographic grains having an aspect ratio of 3 or more may be used as in the light-sensitive material described in Japanese Patent Application No. 61-55509.

The silver halide used in the present invention may be used in combination with two or more kinds of silver halide grains having different halogen compositions, crystal habits, grain sizes and the like.

The grain size distribution of silver halide grains is not particularly limited. For example, monodisperse silver halide grains having a substantially uniform grain size distribution may be used as in the light-sensitive material described in Japanese Patent Application No. 61-55508.

In the present invention, the average grain size of silver halide grains is preferably 0.001 to 10 μm,
More preferably, it is 0.001 to 5 μm.

The amount of silver halide contained in the photosensitive layer is 0.1 mg to 10 in terms of silver including an organic silver salt which is an optional component described later.
It is preferably in the range of g / m ² .

The reducing agent that can be used in the PS plate of the present invention has a function of reducing silver halide and / or a function of accelerating (or suppressing) the polymerization of the polymerizable compound. There are various kinds of substances as the reducing agent having the above function. Examples of the reducing agent include hydroquinones, catechols, p-
Aminophenols, p-phenylenediamines, 3-
Pyrazolidones, 3-aminopyrazoles, 4-amino-5-virazolones, 5-aminouracils, 4,5-
Dihydroxy-6-aminopyrimidines, reductones, aminoreductones, o- or p-sulfonamidophenols, o- or p-sulfonamidonaphthols, 2-sulfonamidoindanones, 4-sulfonamido-5-pyrazolones , 3-sulfonamidoindoles, sulfonamidepyrazolobenzimidazoles, sulfonamidepyrazolotriazoles, α-sulfonamidoketones, hydrazines and the like. By adjusting the type and amount of the reducing agent, it is possible to polymerize the polymerizable compound in the portion where the latent image of silver halide is formed or the portion where the latent image is not formed. In a system in which a polymerizable compound in a portion where a latent image of silver halide is not formed is polymerized, 1
It is particularly preferred to use -phenyl-3-pyrazolidones.

Regarding various reducing agents having the above functions, Japanese Patent Application Nos. 60-22980, 60-29894 and 60-
68874, 60-210657, 60-22
No. 6084, No. 60-227527, No. 60-227.
Nos. 528 and 61-42746 (including those described as developers or hydrazine derivatives)
There is. For the reducing agent, see “The T” by T. James.
heory of the Photographic Process ”Fourth Edition, pp. 291-334 (1977), Research Disclosure Vol. 170, June 1978, 1702.
No. 9 (pages 9 to 15), and Vol. 176, 1987 1
It is also described in February 17643 (pages 22 to 31). Further, as in the light-sensitive material described in Japanese Patent Application No. 61-55505, a reducing agent precursor capable of releasing the reducing agent under heating conditions or in contact with a base is used instead of the reducing agent. May be. Also in the PS plate of the present invention, the reducing agents and reducing agent precursors described in the above specifications and literatures can be effectively used. Therefore, the “reducing agent” in the present specification includes the reducing agents and reducing agent precursors described in the above respective specifications and literatures.

These reducing agents may be used alone, or as described in each of the above specifications, two or more reducing agents may be mixed and used. When two or more reducing agents are used in combination, the reducing agents may interact with each other by first promoting the reduction of silver halide (and / or organic silver salt) by so-called superadditivity. To cause polymerization of the polymerizable compound via an oxidation-reduction reaction with another reducing agent in which the oxidant of the first reducing agent generated by reduction of silver halide (and / or organic silver salt) coexists (Or suppressing the polymerization) is considered. However, in actual use, it is difficult to specify which of the above actions, because the above reactions may occur simultaneously.

Specific examples of the reducing agent include pentadecylhydroquinone, 5-t-butylcatechol, p- (N, N-diethylamino) phenol, 1-phenyl-4-methyl-
4-hydroxymethyl-3-pyrazolidone, 1-phenyl-4-methyl-4-heptadecylcarbonyloxymethyl-3-pyrazolidone, 2-phenylsulfonylamino-4-hexadecyloxy-5-t-octylphenol, 2-phenyl Sulfonylamino-4-t-butyl-5-hexadecyloxyphenol, 2- (N-butylcarbamoyl) -4-phenylsulfonylaminonaphthol, 2- (N-methyl-N-octadecylcarbamoyl) -4-sulfonylaminonaphthol , 1-acetyl-2-phenylhydrazine, 1-acetyl-2-
{(P or o) -aminophenyl} hydrazine, 1-
Formyl-2-{(p or o) -aminophenyl} hydrazine, 1-acetyl-2-{(p or o) -methoxyphenyl} hydrazine, 1-lauroyl-2-
{(P or o) -aminophenyl} hydrazine, 1-
Trityl-2- (2,6-dichloro-4-cyanophenyl) hydrazine, 1-trityl-2-phenylhydrazine, 1-phenyl-2- (2,4,6-trichlorophenyl) hydrazine, 1- {2- (2,5-di-t-pentylphenoxy) butyroyl} -2-{(p or o)
-Aminophenyl} hydrazine, 1- {2- (2,5-
Di-t-pentylphenoxy) butyroyl} -2-
{(P or o) -aminophenyl} hydrazine pentadecyl fluorocaprylate, 3-indazolinone,
1- (3,5-dichlorobenzoyl) -2-phenylhydrazine, 1-trityl-2-[{2-N-butyl-N
-Octylsulfamoyl) -4-methanesulfonyl}
Phenyl] hydrazine, 1- {4- (2,5-di-t-
Pentylphenoxy) butyroyl} -2-{(p or o) -methoxyphenyl} hydrazine, 1- (methoxycarbonylbenzohydryl) -2-phenylhydrazine, 1-formyl-2- [4- {2- (2, 4-di-t
-Pentylphenoxy) butylamido} phenyl] hydrazine, 1-acetyl-2- [4- {2- (2,4-di-t-pentylphenoxy) butylamido} phenyl]
Hydrazine, 1-trityl-2-[{2,6-dichloro-4- (N, N-di-2-ethylhexyl) carbamoyl} phenyl] hydrazine, 1- (methoxycarbonylbenzohydryl) -2- (2,2 4-dichlorophenyl)
Hydrazine, 1-trityl-2-[{2- (N-ethyl-N-octylsulfamoyl) -4-methanesulfonyl} phenyl] hydrazine, 1-benzoyl-2-tritylhydrazine, 1- (4-butoxybenzoyl ) -2
-Tritylhydrazine, 1- (2,4-dimethoxybenzoyl) -2-tritylhydrazine, 1- (4-dibutylcarbamoylbenzoyl) -2-tritylhydrazine, 1- (1-naphthoyl) -2-tritylhydrazine, etc. Can be mentioned.

In the PS plate of the present invention, the reducing agent is preferably used in the range of 0.1 to 1500 mol% with respect to 1 mol of silver (including the above-described silver halide and an organic silver salt which is an optional component). .

The polymerizable compound that can be used in the PS plate of the present invention is not particularly limited, and known polymerizable compounds can be used. As a method of using the PS plate, when a heat development treatment is planned, it is preferable to use a compound having a high boiling point (for example, a boiling point of 80 ° C. or higher) that is hard to volatilize during heating.

The polymerizable compound that can be used in the PS plate of the present invention is generally a compound having addition polymerization or ring-opening polymerization. The compound having an addition-polymerizable group includes a compound having an ethylenically unsaturated group, and the compound having a ring-opening polymerizable group includes a compound having an epoxy group. A compound having an ethylenically unsaturated group is particularly preferable.

Examples of the compound having an ethylenically unsaturated group that can be used in the PS plate of the present invention include acrylic acid and salts thereof, acrylic acid esters, acrylamides, methacrylic acid and salts thereof, methacrylic acid esters, methacrylamides. , Maleic anhydride, maleic acid esters, itaconic acid esters, styrenes, vinyl ethers, vinyl esters, N-vinyl heterocycles, allyl ethers, allyl esters and their derivatives.

Specific examples of the polymerizable compound that can be used in the present invention include acrylic acid esters, and include n-butyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate, benzyl acrylate, furfuryl acrylate, ethoxyethoxy acrylate, dicyclohexyloxyethyl. Acrylate, nonylphenyloxyethyl acrylate hexanediol diacrylate, butanediol acrylate, neopentyl glycol diacrylate, trimethylolpropane triacrylate, pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, polyoxyethylenated bisphenol A diacrylate, hydroxypolyether Mention may be made of re-acrylate, polyester acrylate and polyurethane acrylate, and the like.

Other specific examples of methacrylic acid esters include methyl methacrylate, butyl methacrylate, ethylene glycol dimethacrylate, butanediol dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpropane trimethacrylate, pentaerythritol trimethacrylate, and pentaerythritol tetramethacrylate. Methacrylate and dimethacrylate of polyoxyalkylenated bisphenol A and the like can be mentioned.

The polymerizable compounds may be used alone or in combination of two or more.

In addition, a substance in which a polymerizable functional group such as a vinyl group or a vinylidene group is introduced into the chemical structure of the reducing agent described above can also be used as the polymerizable compound of the present invention. Needless to say, the use of a substance that serves as a reducing agent and a polymerizable compound as described above is also included in the embodiments of the present invention.

In the PS plate of the present invention, the polymerizable compound is preferably used in the range of 50 to 120,000 parts by weight with respect to 1 part by weight of silver halide. A more preferred range of use is 12 to 12000 parts by weight.

The PS plate of the present invention is one in which the silver halide, the reducing agent and the polymerizable compound are contained in the photosensitive layer in a state of being contained in microcapsules.

In the present specification, the “substance contained in the microcapsule” means the substance existing in the core substance and / or the wall material forming the microcapsule.

Various known techniques can be applied to the microcapsules without particular limitation.

As an example of the above-mentioned known technique, US Pat.
US Pat. No. 3,287,154 and British Patent No. 990443, and Japanese Patent Publication Nos. 38-19574 and 42. −
U.S. Pat. No. 3,418,250 and U.S. Pat. No. 3,603,603;
No. 04, a method by precipitation of the polymer described in US Pat. No. 4,967,691; isocyanates described in US Pat. No. 3,796,669.
Method using polyol wall material; US Pat. No. 39145.
A method using the isocyanate wall material described in No. 11; US Pat. Nos. 4,001,140 and 4,087,376.
Urea-formaldehyde-based or urea formaldehyde-resorcinol-based wall forming materials described in U.S. Pat.
Method using a wall forming material such as melamine-formaldehyde resin and hydroxypropyl cellulose described in Japanese Patent No. 25455; JP-B-36-9168 and JP-A-51-51168.
-9079 in sit by polymerization of monomers
u method; British Patent Nos. 952807 and 96507
No. 4, electrolytic dispersion cooling method described in each specification; US Pat. No. 311
1407 and British Patent No. 930422, the spray drying method etc. which are described can be mentioned. The method of microencapsulation is not limited to the above, but a method of forming a polymer film as a microcapsule wall after emulsifying the core substance is particularly preferable.

There is no particular limitation on the wall material of the microcapsule formed based on the above-mentioned known technique. For these wall materials,
Polyurea, polyurethane, polyethylene, polyamide, polyester, polycarbonate, polyethyleneamine, phenol formalin resin, melamine resin, vinyl polymer and vinyl copolymer, polyacrylonitrile,
Examples thereof include polyvinyl acetal resin, cellulose acetate, polyethylene, polypropylene, polybutadiene, gelatin, gum arabic, starch, sodium alginate, ethyl cellulose, carboxymethyl, cellulose, polyvinyl alcohol, and the like, and mixtures thereof.

The above-mentioned microcapsule wall material is preferably a wall material exhibiting thermal softening property by relatively low heating (secondary heating), that is, a wall material having relatively low glass transition temperature. If the glass transition temperature is low, the composition is softened at a low temperature, and the polymerizable monomer is eluted from the uncured microcapsules (including the core substance) to easily form a lipophilic uniform film as the image area.
Such a glass transition temperature is preferably in the range of 80 to 300 ° C., more preferably 80 to 25 ° C.
It is in the range of 0 ° C., and further in the range of 80 to 220 ° C. However, the above glass transition temperature is Hybron DDV-
It is a value measured using a type II (manufactured by Toyo Baldwin Co., Ltd.) at a heating rate of 2 ° C./min. When the glass transition temperature is lower than the above range, the microcapsules have poor stability over time. Further, when the glass transition temperature is higher than the above range, the heating temperature must be set high, which adversely affects the support itself.

From the above viewpoints, the wall material of the microcapsule is preferably polyurea, polyurethane, polyester, polycarbonate, polyamide, or a mixture thereof, and particularly preferably polyurea and polyurethane.

The particle size of the microcapsules formed of such a wall material is preferably in the range of 0.01 to 30 μm, and particularly 0.01 to 10 μm from the viewpoint of handling.
Is more preferable, and it is more preferable that it is in the range of 0.01 to 5 μm from the viewpoint of resolution.

The water resistant hydrophilic binder used in the PS plate of the present invention is a hydrophilic binder to which water resistance (water insolubility) is imparted. The hydrophilic binder is preferably transparent or translucent, and as such a hydrophilic binder, gelatin, gelatin derivatives, carboxymethyl cellulose, cellulose derivatives such as methyl cellulose,
Natural substances such as starch, polysaccharides such as arabic gum,
Examples thereof include synthetic polymer substances such as polyvinyl alcohol, polyvinylpyrrolidone, acrylamide polymers, polyacrylic acid, and water-soluble polyvinyl compounds such as vinyl acetate-acrylic acid copolymers. The above can be used alone or in appropriate combination.

The water resistance is imparted to the hydrophilic binder by adding a water resistant agent to the binder. As a result, water resistance is imparted particularly to the portion where the hydrophilic binder appears on the surface (non-image area), and the printing durability can be improved. Examples of the water-proofing agent include melamine formaldehyde, urea resin, and other amino resin initial condensates, glutaraldehyde, glyoxal, modified polyamide resins, methylolated melamine, and other crosslinking agents. Regarding the waterproofing agent, for example, JP-A-61-379.
The description is given in JP-A-7. The waterproofing agent is the P of the present invention.
A curing reaction occurs in the step of forming the photosensitive layer of the S plate, and a water-resistant (water-insoluble) hydrophilic binder is obtained.

The mixing weight ratio of the hydrophilic binder and the waterproofing agent varies depending on the type of the binder and waterproofing agent used, but is generally preferably in the range of 4: 1 to 1: 4.

The water-resistant support used in the present invention can be appropriately selected from known support materials and used. Specifically, paper, synthetic paper, plastic (for example, polyethylene, polypropylene, polystyrene, etc.) laminated paper, aluminum (including aluminum alloy),
Metal plates such as zinc, iron, copper, cellulose acetate,
Examples thereof include plastic films such as cellulose propionate, cellulose acetate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, and papers or plastic films on which the above metals are laminated or vapor deposited. Among these, paper, synthetic paper,
Polyethylene terephthalate, polycarbonate and aluminum plate are preferred. The paper support is described in JP-A-61-3797 and JP-A-61-112150.

These supports are subjected to surface roughening treatment (graining treatment) or surface hydrophilic treatment as necessary.

In the above description, the photosensitive layer includes a microcapsule and a hydrophilic binder that is water-resistant, that is, the photosensitive layer has a certain degree of hardness and is formed in a water-insoluble state. About the original edition.

A lithographic printing original plate which is another embodiment of the present invention will be described below. That is, it is a lithographic printing plate precursor in which the photosensitive layer contains a microcapsule together with a hydrophilic binder and a waterproofing agent. In this lithographic printing original plate, the photosensitive layer is configured so that the hydrophilic binder and the water-proofing agent are rendered water-resistant by a subsequent treatment.

The water-proofing agent in this case is not particularly limited, and known ones containing the above-mentioned water-proofing agent can be used, but the lithographic printing original plate of the present invention mainly involves a heat development treatment (primary heat treatment). Therefore, it is preferable to use a water-proofing agent that can cause the photosensitive layer containing the hydrophilic polymer to undergo a curing reaction and become in a water-insoluble state by this heating. Incidentally, imparting water resistance to the hydrophilic polymer is not limited to the above thermal development,
It may be performed at the time of secondary heating, or may be performed by another treatment, for example, irradiation with light or the like. Among the water-proofing agents of the type that cause a polymerization and curing reaction by heating, there are methylolated melamine and the like among the above.

Hereinafter, various aspects of the PS plate of the present invention, optional components that can be contained in the photosensitive layer, and auxiliary layers that can be optionally provided in the PS plate will be sequentially described.

As described above, the PS plate of the present invention contains silver halide, a reducing agent, and a polymerizable compound in microcapsules. The microcapsules may contain any component that can be contained in the photosensitive layer described later. When the silver halide is contained in the microcapsules, it is preferable that the silver halide be present in the wall material forming the outer shell of the microcapsules.

The optional components that can be contained in the photosensitive layer of the PS plate of the present invention include color image-forming substances, sensitizing dyes, organic silver salts,
Various image forming accelerators (eg, bases or base precursors, oils, surfactants, compounds having an antifoggant function and / or development promoting function, thermal solvents, compounds having an oxygen removing function, etc.), thermal polymerization inhibitors, Thermal polymerization initiator,
Development stopper, fluorescent brightening agent, anti-fading agent, halation or anti-irradiation dye, matting agent, anti-smudge agent, plasticizer, water releasing agent, binder, photo-polymerization initiator, solvent for polymerizable compound, etc. .

The color image-forming substance that can be used in the PS plate of the present invention is not particularly limited, and various types can be used. By including the color image forming substance in the photosensitive layer, the image area or the non-image area can be colored, and the two can be easily distinguished.
Examples of such examples are substances that are themselves colored (pigments or dyes), or energy that is colorless or pale but is external (heat, pressure, light irradiation, etc.),
A substance (color former) that develops a color upon contact with another component (developing agent) is also included in the color image-forming substance that can be used in the present invention. The color image forming substance is described in JP-A-61-7.
It is described in detail in the light-sensitive material described in Japanese Patent No. 3145. Further, Japanese Patent Application No. 61-29987 discloses a photosensitive material using a dye or pigment as a color image forming substance, and Japanese Patent Application No. 61-29987 discloses a photosensitive material using a leuco dye.
-53876, Japanese Patent Application Nos. 61-133091, and 61-133092, each has a description,
The color image-forming substance used in these is also the PS of the present invention.
Can be used for printing.

The sensitizing dye that can be used in the present invention is not particularly limited, and a silver halide sensitizing dye known in the photographic art and the like can be used. The sensitizing dyes include methine dyes, cyanine dyes, merocyanine dyes, complex cyanine dyes, holopolar cyanine dyes, hemicyanine dyes, styryl dyes and hemioxole dyes. These sensitizing dyes may be used alone or in combination. In particular, for the purpose of supersensitization, it is common to use a combination of sensitizing dyes. Further, together with the sensitizing dye, a dye which does not have a spectral sensitizing effect itself, or a substance which does not substantially absorb visible light but exhibits supersensitization may be used together. The addition amount of the sensitizing dye is generally about 10 ^{-8 to} 10 ^-2 mol per mol of silver halide. The sensitizing dye is preferably added at the stage of preparing a silver halide emulsion described below.

Specific examples of the sensitizing dye are described in the above-mentioned Japanese Patent Application No. 60-1397.
No. 46 and No. 61-55510, and these sensitizing dyes can also be used.

In the present invention, the addition of the organic silver salt is particularly effective in the heat development processing. That is, when heated to a temperature of 80 ° C. or higher, the organic silver salt is considered to participate in the redox reaction using the latent image of silver halide as a catalyst. in this case,
It is preferable that the silver halide and the organic silver salt are in contact with or in close proximity to each other. As the organic compound that constitutes the organic silver salt, an aliphatic or aromatic carboxylic acid,
Examples thereof include thiocarbonyl group-containing compounds having a mercapto group or α-hydrogen, and imino group-containing compounds. Among them, benzotriazole is particularly preferable. The organic silver salt is generally a silver halide 1
It is used in an amount of 0.01 to 10 mol, preferably 0.01 to 1 mol, per mol. The same effect can be obtained by adding an organic compound (for example, benzotriazole) constituting the organic silver salt to the photosensitive layer instead of the organic silver salt. Specific examples of organic silver salts are described in the light-sensitive material of Japanese Patent Application No. 60-141799.

Various image forming accelerators can be used in the PS plate of the present invention. The image forming accelerator has a function of promoting the redox reaction between the silver halide (and / or organic silver salt) and the reducing agent and the redox agent. The image forming accelerator is a base or a base precursor, an oil, a surfactant, a compound having an antifoggant function and / or a development promoting function, a thermal solvent, a compound having an oxygen removing function, etc. Is further classified into. However, these substance groups generally have a composite function, and usually have some of the above-mentioned accelerating effects together. Therefore, the above classification is convenient, and in fact, one compound often has a plurality of functions.

Examples of image forming accelerators include bases, base precursors, oils, surfactants, compounds having an antifoggant function and / or development promoting function, thermal solvents, and compounds having an oxygen removing function.

Examples of preferable bases include alkali metal or alkaline earth metal hydroxides as inorganic bases; alkali metal or alkaline earth metal tertiary phosphates, borates,
Carbonates, metaborates; combinations of zinc hydroxide or zinc oxide with chelating agents such as sodium picolinate;
Ammonium hydroxides; quaternary alkyl ammonium hydroxides; hydroxides of other metals, and the like, and organic bases include aliphatic amines (trialkylamines,
Hydroxylamines, aliphatic polyamines); Aromatic amines (N-alkyl-substituted aromatic amines, N-hydroxylalkyl-substituted aromatic amines and bis [p-
(Dialkylamino) phenyl] methanes), heterocyclic amines, amidines, cyclic amidines, guanidines, cyclic guanidines, and the like, with a pKa of 7 or more being particularly preferable.

Examples of the base precursor include salts of organic acids and bases that are decarboxylated by heating, compounds that release amines by reactions such as intramolecular nucleophilic substitution reaction, Rossen rearrangement, Beckmann rearrangement, etc. Compounds that release and generate a base by electrolysis are preferably used. Specific examples of the base precursor include guanidine trichloroacetic acid, piperidine trichloroacetic acid, morpholine trichloroacetic acid, p-toluidine trichloroacetic acid, 2-picoline trichloroacetic acid, phenylsulfonylacetic acid guanidine, 4-chlorophenylsulfonylacetic acid guanidine, and 4-methyl-. Mention may be made of guanidine sulfonylphenylsulfonylacetate and guanidine acetate 4-acetylaminomethylpropiol.

The base or base precursor can be used in a wide range of amounts in the PS plate of the present invention. The base or base precursor is 100% by weight in terms of the coating film of the photosensitive layer.
It is suitable to be used below, more preferably 0.1
A range of wt% to 40 wt% is useful. In the present invention, the base and / or base precursor may be used alone or as a mixture of two or more kinds.

For a light-sensitive material using a tertiary amine as a base or a base precursor, see Japanese Patent Application No. 61-1318.
No. 1 describes a light-sensitive material using a fine particle dispersion of a hydrophobic organic base compound having a melting point of 80 to 180 ° C.
Japanese Patent Application No. 61-52992 describes photosensitive materials using a hydroxide or salt of an alkali metal or an alkaline earth metal, and Japanese Patent Application No. 61-96341 discloses the same and uses them. The known bases and base precursors can also be used in the PS plate of the present invention.

When a base or a base precursor is used in the PS plate of the present invention, it is preferable that the base or the base precursor is present in the photosensitive layer outside the microcapsules described above. Alternatively, the base or base precursor may be contained in a microcapsule different from the above-mentioned microcapsule. It may be added to an auxiliary layer (a layer containing a base or a base precursor described later) other than the photosensitive layer.

As the oil, a high boiling point organic solvent used as a solvent for emulsifying and dispersing a hydrophobic compound can be used.

Examples of the surfactant include pyridinium salts, ammonium salts, phosphonium salts described in JP-A-59-74547, polyalkylene oxides described in JP-A-59-57231, and the like. Can also be used in the PS plate of the present invention.

The compound having the fog-preventing function and / or the development-accelerating function can be used for the purpose of clearly obtaining the image area and the non-image area. Regarding a light-sensitive material using an antifoggant as a compound having an antifoggant function and / or a development promoting function, Japanese Patent Application No. 60-294
No. 337, for a light-sensitive material using a compound having a cyclic amide structure, Japanese Patent Application No. 60-294338, and for a light-sensitive material using a thioether compound, Japanese Patent Application No. 60-294339. Japanese Patent Application No. Sho 6 for a photosensitive material using a polyethylene glycol derivative.
No. 0-294340, a light-sensitive material using a thiol derivative is described in Japanese Patent Application No. 60-294341, and a light-sensitive material using an acetylene compound is described in Japanese Patent Application No. 61-20438, sulfonamide. Regarding the photosensitive material using the derivative, Japanese Patent Application No. 61-25573.
Each of them is described in the specification, and the compounds used therein can also be used in the PS plate of the present invention.

As the hot solvent, a compound which can be a solvent for the reducing agent, a compound which is a substance having a high dielectric constant and is known to accelerate the physical development of the silver salt, and the like are useful. As a useful thermal solvent,
Polyethylene glycols described in U.S. Pat. No. 3,347,675, derivatives of polyethylene oxide such as oleic acid ester, beeswax, monostearin and -SO.
High dielectric constant compounds having _2- and / or -CO- groups, polar substances described in U.S. Pat. No. 3,667,959, 1,10-decanediol described in Research Disclosure, December 1976, pages 26-28. , Methyl anisate, biphenyl suberate and the like are preferably used.

The compound having a function of removing oxygen can be used for the purpose of eliminating the influence of oxygen during development (oxygen has a polymerization inhibiting action). Examples of the compound having an oxygen removing function include compounds having two or more mercapto groups.

The thermal polymerization initiator that can be used in the PS plate of the present invention is
Generally, it is thermally decomposed under heating to initiate polymerization (especially radicals)
It is a compound that gives rise to, and is usually used as an initiator of radical polymerization. Regarding the thermal polymerization initiator, “Additional Polymerization
Ring-opening polymerization ", 1983, Kyoritsu Shuppan), pp. 6-18. Specific examples of the thermal polymerization initiator,
Azobisisobutyronitrile, 1,1'-azobis (1
-Cyclohexanecarbonitrile), dimethyl-2,
2'-azobisisobutyrate, 2,2-azobis (2
-Methyl butyronitrile), azo compounds such as azobisdimethylvaleronitrile, benzoyl peroxide, di-t-peroxide, dicumyl peroxide, t-butyl hydroperoxide, cumene hydroperoxide and other organic peroxides Inorganic peroxides such as hydrogen peroxide, potassium persulfate and ammonium persulfate, and sodium p-toluenesulfinate. The thermal polymerization initiator is preferably used in the range of 0.1 to 120% by weight, more preferably 1 to 10% by weight, based on the polymerizable compound. In the case of the present invention,
In the system for polymerizing the polymerizable compound in the portion where the latent image of silver halide is not formed, it is preferable that the thermal polymerization initiator is contained in the microcapsule together with silver halide and the like. A light-sensitive material using a thermal polymerization initiator is described in Japanese Patent Application No. 60-210657, and the thermal polymerization initiator used therein can also be used in the PS plate of the present invention.

The development terminator that can be used in the PS plate of the present invention is
After proper development, it is a compound that neutralizes or reacts with a base to reduce the concentration of the base in the film to stop the development, or a compound that interacts with silver and a silver salt to suppress the development. Specific examples thereof include an acid precursor that releases an acid when heated, an electrophilic compound that causes a substitution reaction with a coexisting base when heated, a nitrogen-containing heterocyclic compound, and a mercapto compound. Examples of acid precursors include oxime esters described in JP-A-60-108837 and JP-A-60-192939, and Japanese Patent Application No. 59-858.
Examples thereof include compounds releasing an acid by the Rossen rearrangement described in No. 34. In addition, as an example of an electrophilic compound which undergoes a substitution reaction with a base upon heating, Japanese Patent Application Laid-Open No.
Examples thereof include compounds described in 0-230134.

The anti-smudge agent used in the PS plate of the present invention includes
Particulate matter that is solid at room temperature is preferable. Specific examples thereof include starch particles described in British Patent No. 12,322,347, polymer fine powders described in US Pat. No. 3,625,736, and British Patent No. 1,235,991. Colorant-free microcapsule particles described in US Pat. No. 2,711,375, inorganic fine particles such as cellulose fine powder described in US Pat. No. 2,711,375, talc, kaolin, bentonite, pyrophyllite, zinc oxide, titanium dioxide, and alumina. Etc. can be mentioned. The average particle size of the particles is preferably in the range of 3 to 50 μm in volume average diameter, and more preferably in the range of 5 to 40 μm. When the polymerizable compound or the like is in the microcapsule state as described above, it is more effective that the particles are larger than the microcapsules.

In addition to the examples described above, examples of optional components that can be contained in the photosensitive layer and usage thereof are also described in the application specification regarding the series of photosensitive materials described above, and Research Disclosure Vol. 170, June 1978. The 170th
No. 29 (pages 9 to 15).

The auxiliary layer that can be optionally provided in the PS plate of the present invention includes a heating element layer, an antistatic layer, an anti-curl layer, a peeling layer, a cover sheet or a protective layer, a layer containing a base or a base precursor, and a base barrier layer. Etc. can be mentioned.

Hereinafter, a method for manufacturing the PS plate of the present invention will be described.

Although various methods can be used as the method for producing the PS plate, the general method is to prepare a liquid composition by dissolving, emulsifying or dispersing the components of the photosensitive layer in a suitable solvent. The method comprises the steps of microencapsulating the composition and further preparing a coating solution containing a microcapsule dispersion, and coating the coating solution on a water-resistant support and drying.

Generally, a coating liquid containing the above-mentioned microcapsule dispersion liquid is prepared by mixing each liquid composition prepared for each component and then microcapsulating the liquid composition. The liquid composition may be prepared for each component, or may be prepared to contain a plurality of components. A part of the components of the photosensitive layer may be added and used at the stage of preparing the liquid composition or the coating solution or after the preparation.
Further, a method of preparing a secondary composition by further emulsifying an oily (or aqueous) composition containing one or more components in an aqueous (or oily) solvent can also be used.

With respect to the main components contained in the photosensitive layer, a method for preparing a liquid composition and a coating liquid is shown below.

In the production of the PS plate of the present invention, silver halide is preferably prepared as a silver halide emulsion. There are various methods known in the photographic art for the preparation of silver halide emulsions, but there is no particular limitation regarding the production of the PS plate of the present invention. The silver halide emulsion can be prepared by any of the acidic method, the neutral method and the ammonia method. The reaction mode of the soluble silver salt and the soluble halogen salt may be a one-sided mixing method, a simultaneous mixing method, or a combination thereof. A back-mixing method in which grains are mixed under the condition of excess silver ions and a controlled double jet method in which pAg is kept constant can also be adopted. Also, the silver halide emulsion is
The latent image may be a surface latent image type in which a latent image is mainly formed on the surface of a particle or an internal latent image type in which a latent image is formed inside a particle. A direct reversal emulsion in which an internal latent image type emulsion and a nucleating agent are combined can also be used.

In the preparation of the silver halide emulsion used for producing the PS plate of the present invention, it is preferable to use a hydrophilic colloid as the protective colloid. Examples of hydrophilic colloids include gelatin, gelatin derivatives, graft polymers of gelatin and other high molecular substances, proteins such as albumin and casein; derivatives such as hydroxyethyl cellulose, carboxymethyl cellulose, cellulose sulfates, and alginic acid. Derivatives such as soda and starch derivatives; and polyvinyl alcohol, polyvinyl alcohol partial acetals, poly-N-vinylpyrrolidone, polyacrylic acid, polymethacrylic acid, polyacrylamide,
There may be mentioned various synthetic hydrophilic polymer substances such as a single or copolymer such as polyvinyl imidazole and polyvinyl pyrazole. Of these, gelatin is preferred. As for gelatin, besides lime-processed gelatin,
Acid-processed gelatin or enzyme-processed gelatin may be used, and a hydrolyzate or enzyme-processed decomposition product of gelatin may also be used.

In the production of the PS plate of the present invention, when a silver halide emulsion prepared by using a hydrophilic colloid is used, the sensitivity of the PS plate is improved. The silver halide emulsion contains ammonia, an organic thioether derivative (see JP-B-47-386), and a sulfur-containing compound (JP-A-53-1443) as a silver halide solvent in the step of forming silver halide grains.
No. 19) can be used. Further, in the process of grain formation or physical ripening, a cadmium salt, a zinc salt, a lead salt, a thallium salt or the like may coexist. Further, for the purpose of improving the high illuminance failure and the low illuminance failure, a water-soluble iridium salt such as iridium chloride (III valence or IV valence), hexachloroiridium ammonium salt, or a water-soluble rhodium salt such as rhodium chloride can be used.

Soluble salts may be removed from the silver halide emulsion after formation of a precipitate or after physical ripening. In this case, it can be carried out according to the Nudel washing method or the sedimentation method. The silver halide emulsion may be used without ripening, but it is usually chemically sensitized before use. In the emulsion for a conventional type light-sensitive material, known sulfur sensitizing method, reduction sensitizing method, noble metal sensitizing method and the like are used singly or in combination, but they can be applied in the production of the PS plate of the present invention.

When a sensitizing dye is added to the silver halide emulsion,
It is preferably added at the stage of preparing a silver halide emulsion (Japanese Patent Application Nos. 60-139746 and 61-5).
5510).

When a nitrogen-containing heterocyclic compound is added as the compound having the fog-preventing function and / or the development-accelerating function, it should be added in the step of forming silver halide grains or the step of ripening in the preparation of a silver halide emulsion. Is preferred (see Japanese Patent Application No. 61-3024).

Further, when the above-mentioned organic silver salt is contained in the photosensitive layer,
An organic silver salt emulsion can be prepared by a method similar to the method for preparing a silver halide emulsion described above. And it is preferable that this organic silver salt is also contained in the microcapsules.

In the production of the PS plate of the present invention, the polymerizable compound can be used as a medium for preparing the composition of other components in the photosensitive layer. For example, a silver halide (including a silver halide emulsion), a reducing agent and the like can be dissolved, emulsified or dispersed in a polymerizable compound and used in the production of a PS plate. This allows the above components to be easily dispersed in the oil droplets of the polymerizable compound. Further, in this case, components such as a wall material required for microcapsulation may be included in the oil droplets.

The photosensitive composition containing a polymerizable compound containing silver halide can be prepared using a silver halide emulsion.
In addition to the silver halide emulsion, a silver halide powder prepared by freeze-drying or the like can be used for the preparation of the photosensitive composition.

The photosensitive composition can be obtained by charging the above silver halide, the polymerizable compound, the reducing agent, and other optional components into a commonly used stirrer (homogenizer, blender, mixer, etc.) and stirring. .

In addition, it is preferable to dissolve a copolymer composed of a hydrophilic repeating unit and a hydrophobic repeating unit in the polymerizable compound used for preparing the photosensitive composition (see Japanese Patent Application No. 60-261887). ).

Further, instead of using the above-mentioned copolymer, a photosensitive composition may be prepared by dispersing microcapsules containing a silver halide emulsion as a core substance in a polymerizable compound (Japanese Patent Application No. Sho 6-62).
1-5750).

The photosensitive composition thus obtained is then encapsulated according to the method for forming an outer shell described above to prepare a capsule dispersion containing a silver halide, a reducing agent and a polymerizable compound. As described above, some optional components can be added to the microcapsule dispersion liquid.

The above-mentioned hydrophilic binder and water-proofing agent are added to the capsule dispersion prepared as described above to prepare a photosensitive layer-forming coating solution. At this time, an optional component such as a surfactant may be added if necessary. The hydrophilic binder and the like can be added before the microencapsulation.

The PS plate of the present invention can be manufactured by applying the coating solution for forming a photosensitive layer thus prepared onto the support described above and drying. The coating of the coating liquid on the support is
It can be easily implemented according to known techniques.

Next, each step of the method for producing a printing plate of the present invention will be described.

The PS plate of the present invention is subjected to development treatment at the same time as imagewise exposure or after imagewise exposure, and then subjected to lipophilic film-forming treatment of unpolymerized portions for use.

As the above-mentioned exposure method, various exposure means can be used, but generally a latent image of silver halide is obtained by imagewise exposure to radiation including visible light. The type of light source and the amount of exposure can be selected according to the photosensitive wavelength of silver halide (the wavelength sensitized when dye sensitization is performed) and the sensitivity. Examples of these include a mercury lamp, a metal halide lamp, a xenon lamp, a chemical lamp, a carbon arc lamp, a tungsten lamp or an infrared lamp. Scanning exposure with a laser beam can also be used in the present invention. Examples of such a laser beam include a semiconductor laser, a helium / neon laser, an argon laser, a krypton ion laser, and a helium / cadmium laser.

The PS plate of the present invention is subjected to a heat development treatment (Japanese Patent Application Laid-Open No. 6-58242).
1-69062) has advantages such as easy operation and processing in a short time. Therefore, it is adopted as a development processing method.

As a heating (primary heating) method in the heat development treatment, various conventionally known methods can be used. As the heat development treatment, the above-mentioned Japanese Patent Application No. 60-1355 is used.
In the light-sensitive layer, such as the method described in Japanese Patent Application No. 61-55506, in which a heat-generating layer is formed on the light-sensitive material and used as a heating means, as in the light-sensitive material described in Japanese Patent No. 68. It is also possible to use a method of carrying out the heat development treatment while suppressing the amount of oxygen existing in the. The heating temperature is generally 80 ° C to 200 ° C, preferably 100 ° C to 160 ° C. The heating time is generally 1 second to 5 seconds.
Minutes, preferably 5 seconds to 1 minute.

The PS plate of the present invention is subjected to heat development treatment as described above to polymerize the polymerizable compound in the portion where the latent image of silver halide is formed or the portion where the latent image of silver halide is not formed. it can. In the PS plate of the present invention, generally, in the heat development treatment, the polymerizable compound in the portion where the latent image of silver halide is formed is polymerized, but by adjusting the kind and amount of the reducing agent, the halogen It is also possible to polymerize a portion of the polymerizable compound in which a latent image of silver halide is not formed (see Japanese Patent Application No. 60-210657).

In the method for producing a printing plate of the present invention, the steps of the imagewise exposure, the thermal development (primary heating), and the secondary heating are sequentially carried out. The secondary heating will be described below.

First, when the PS plate of the present invention is subjected to pattern exposure and heating (primary heating) development using the above-mentioned exposure means, the microcapsules (including the core substance) in the exposed portions (portions to be non-image areas) are As described above, the polymerization reaction progresses to polymerize and cure, and the heat softening temperature of the capsule rises. That is, the heat-softening temperature of the microcapsules in the cured portion is equal to or higher than the heat-softening temperature of the microcapsules in the unpolymerized (uncured) portion. Therefore, the polymerized and cured microcapsules are heated at a higher temperature (secondary heating: below the heat softening temperature of the cured portion,
Even at a temperature above the heat softening temperature of the uncured portion, the microcapsules do not soften, fuse, melt, break, or elute the core substance in the microcapsules, and the microcapsules are surrounded by a water-resistant hydrophilic binder. It exists in the form of microcapsules and becomes a non-image area (hydrophilic portion). On the other hand, the microcapsules in the unexposed area are in an uncured state,
The microcapsule (the part that becomes the image area) of this part is
It is stable during normal handling and under normal conditions, but is heated above the heating phenomenon temperature (secondary heating: below the heat-softening temperature of the microcapsules in the hardened part, above the heat-softening temperature of the microcapsules in the uncured part). (At temperature) softens, fuses, melts, breaks, microcapsule walls and / or
Alternatively, the core substances in the microcapsules are mixed with each other to form a lipophilic uniform film to form an image area (ink-accepting area).

As described above, a lithographic printing plate having an image area (lipophilic) and a non-image area (hydrophilic) can be produced.

In the above manufacturing method, the secondary heating can be included in the first heat development. That is, heating may be continuously performed at a certain suitable temperature (a constant temperature may be changed stepwise or with a temperature gradient). Also,
In addition to the secondary heating, a pressing means may be used in combination to pressurize the microcapsules to form a lipophilic uniform film in the same manner as above.

The above-mentioned photosensitive layer is a method for producing a lithographic printing plate using a PS plate having a structure in which a hydrophilic binder is already made water resistant by a waterproofing agent and is in a water-insoluble state. A lithographic printing plate can also be produced in the same manner as the PS plate configured to have water resistance during the lithographic printing plate production process (heat treatment process).

Further, the above description has described the method for producing a lithographic printing plate obtained by using a system in which a polymerizable compound in a portion where a latent image of silver halide is formed is generally used. As described above, a lithographic printing plate can be similarly obtained in a system in which a polymerizable compound in a portion where a latent image is not formed is polymerized.

The PS plate of the present invention is advantageously used for offset printing and the like.

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto.

[Example 1] [Preparation of PS plate] A PS plate was prepared as follows.

Preparation of silver halide emulsion 40 g of gelatin and potassium bromide were dissolved in 3 parts of water,
Heat to 0 ° C and add 34 g of silver nitrate to water with continuous stirring.
What was melt | dissolved in 00m was added in 10 minutes. Then, a solution prepared by dissolving 3.3 g of potassium iodide in 100 m of water was added over 2 minutes. The pH of the silver iodobromide emulsion thus obtained was adjusted, allowed to settle, excess salts were removed, the pH was adjusted to 6.0, and tetrahedral monodispersed silver bromide with an average grain size of 0.2 μm was used. An emulsion was obtained. The yield of emulsion was 400 g.

Preparation of benzotriazole silver emulsion 28 g of gelatin and 13.2 g of benzotriazole were added to 3 parts of water.
It was melted in 000m. The solution was stirred while maintaining the temperature at 40 ° C., and a solution prepared by dissolving 17 g of silver nitrate in 100 m of water was added over 2 minutes. Excess salt was precipitated and removed by adjusting the pH of the obtained emulsion. Then, the pH was adjusted to 6.30 to obtain a benzotriazole silver emulsion. The yield of emulsion was 400 g.

Preparation of Photosensitive Composition 0.40 g of the following copolymer was dissolved in 100 g of trimethylolpropane triacrylate. Solution 1 above
To 0.8 g, 0.22 g of Emarex NP-8 (manufactured by Nippon Emulsion Co., Ltd.) and 0.65 of the following hydrazine derivative
g, and a solution prepared by dissolving 0.73 g of the following developer in 2.4 g of methylene chloride was added. To the above solution, a mixture of 2.4 g of silver halide emulsion prepared above, 2 g of silver benzotriazole emulsion, and 0.066 g of benzotriazole was added, and the mixture was homogenized at 15,000 min.
It stirred for 5 minutes by rotation and the photosensitive composition was obtained.

(Developer) (Copolymer) (Hydrazine derivative) Preparation of Photosensitive Microcapsule Liquid Addition product of xylylene diisocyanate and trimethylolpropane (Takenate D110) in the above photosensitive composition.
4 g of N, trade name, Takeda Pharmaceutical Co., Ltd. was added to 25 g of a 2% aqueous solution of polyvinyl alcohol (PVA-205, Kuraray Co., Ltd.) and homogenized at 18000 rpm for 5 minutes. The mixture was stirred and emulsified. This emulsion was reacted for 2 hours under stirring at 1000 rpm to obtain a dispersion liquid of photosensitive microcapsules in which the photosensitive composition was contained in the microcapsules composed of the outer shell of polyurea resin.

Preparation of PS plate To 10.0 g of the above microcapsule dispersion, a 10% aqueous solution of guanidine trichloroacetate (water: ethanol =
1.8 g of a 1: 1 (volume ratio) mixed solution, 10 g of water and 0.2 g of white dextrin (manufactured by Nippon Starch Chemical Co., Ltd.), polyvinyl alcohol (PVA-205, manufactured by Kuraray Co., Ltd.).
5 g and 0.3 g of a 10% methylolated melamine aqueous solution were added to prepare a coating liquid for forming a photosensitive layer. This coating solution was applied onto art paper so that the weight after drying was 5 g / m ² to obtain a PS plate.

[Evaluation as PS Plate] The PS plate obtained above was imagewise exposed to 200 lux for 1 second using a tungsten bulb, and then placed on a hot plate heated to 125 ° C. and heated for 60 seconds. Then 170 ℃
After heating for 1 minute at 80 ° C., a lithographic printing plate was obtained. Heidelberg G. T. When it was attached to an O-type printing machine and printed, a printed matter free from stains was obtained.

Claims (8)

[Claims] 1. A lithographic printing plate precursor having a water-resistant support provided with a microcapsule containing a silver halide, a reducing agent and a polymerizable compound, and a photosensitive layer containing a water-resistant hydrophilic binder. Likewise, a step of heating the lithographic printing original plate for heat development to cure the microcapsules, and a step of heating the lithographic printing original plate at a temperature higher than the heat development temperature to soften the uncured microcapsules, A method for producing a lithographic printing plate comprising the steps of fusing, melting or breaking to form an oleophilic film having ink receptivity. 2. The method for producing a lithographic printing plate according to claim 1, wherein the photosensitive layer further contains an organic silver salt, and the organic silver salt is present in the microcapsules. 3. The photosensitive layer further contains a thermal polymerization initiator,
The method for producing a lithographic printing plate according to claim 1, wherein the thermal polymerization initiator is present in the microcapsules. 4. The method for producing a lithographic printing plate according to claim 1, wherein at least a part of the silver halide is contained in the wall material of the microcapsules. 5. A lithographic printing plate precursor is imagewise formed with a photosensitive layer containing microcapsules containing a silver halide, a reducing agent and a polymerizable compound, a hydrophilic binder and a water-proofing agent on a water-resistant support. The step of exposing, the step of heating the lithographic printing original plate to perform heat development to cure the microcapsules, and the step of heating the lithographic printing original plate at a temperature higher than the heat development temperature to soften and melt the uncured microcapsules. A method for producing a lithographic printing plate comprising the steps of depositing, melting or destroying, thereby forming an oleophilic film having ink receptivity. 6. The method for producing a lithographic printing plate according to claim 5, wherein the photosensitive layer further contains an organic silver salt, and the organic silver salt is present in the microcapsules. 7. The photosensitive layer further contains a thermal polymerization initiator,
The method for producing a lithographic printing plate according to claim 5, wherein the thermal polymerization initiator is present in the microcapsules. 8. The method for producing a lithographic printing plate according to claim 5, wherein at least a part of the silver halide is contained in the wall material of the microcapsules.