JPS61230150A - Photosensitive printing plate - Google Patents

Abstract

PURPOSE:To eliminate the need for an adding stage for the purpose of surface matting by incorporating pulverous materials which are insoluble in a solvent for forming a photosensitive layer and soluble in a developing soln. into a photosensitive compsn. CONSTITUTION:The following pulverous materials are used if the solvent for forming the photosensitive layer is an org. solvent such as acetone or methyl carbitol and if the developing soln. is an aq. soln. or water-base soln. contg. an alkaline agent: For example, gelatin, casein, gum arabic, alginic acid, etc. are exemplified as the natural high-polymer compd. Homopolymers or copolymers consisting of monomers having functional groups such as, for example, carboxylic acid, sulfonic acid, arom. hydroxyl group and amide are exemplified as the synthetic high-polymer compd. The surface of the photosensitive layer is matted if the photosensitive layer is formed of the photosensitive compsn. contg. the above-mentioned materials and therefore the need for a coating state and heating stage for matting is eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to photosensitive printing plates, and in particular to improving the adhesion when performing a vacuum adhesion method in which a film base plate is brought into close contact with a photosensitive printing plate during exposure during plate making. This invention relates to a photosensitive printing plate in which the surface of the photosensitive printing original plate is roughened for quick printing.

BACKGROUND OF THE INVENTION Printing plates, such as lithographic printing plates, are made from photosensitive printing plates. For example, in order to create a lithographic printing plate, a photosensitive lithographic printing plate having a photosensitive layer on a support such as a surface-treated aluminum Ecum plate is created, and a film original plate of the original is placed on the photosensitive layer of the photosensitive lithographic printing plate. The photosensitive layer is exposed to light, and the strength of the light corresponds to the brightness and darkness of the original image to form a soluble area and an insoluble or poorly soluble area in the developer, and the soluble area is dissolved in the developer. By removing it, an image area and a non-image area are formed. Since the image area becomes lipophilic and the non-image area becomes hydrophilic, the oleophilic printing ink adheres only to the image area and is transferred to the printing medium such as paper. By the way, when applying the film original plate, if the film original plate is exposed without being brought into close contact with the photosensitive layer, the image formed on the photosensitive layer will be blurred, so work efficiency is determined by how reliably and quickly this contact is made. This is important in that respect. Conventionally, there are methods for bringing the original film plate into close contact with this photosensitive layer.
A vacuum contact method is used.

In this method, a film original plate and a photosensitive lithographic printing plate are sandwiched between a glass plate and a rubber sheet, with the photosensitive layer overlapping the film original plate, and these are supported in a vacuum printing frame. This is to create a vacuum between the sheets and bring the film original plate and photosensitive printing original plate into close contact. By the way, since the surface of conventional photosensitive printing plates is smooth,
According to the vacuum adhesion method described above, the air between the film original plate and the photosensitive layer is removed from the periphery and the two are gradually brought into close contact from the periphery, so it is difficult to remove the air from the center of the film ( However, it takes an extremely long time to remove this and bring the film base plate into close contact with the entire surface of the photosensitive printing base plate.This reduces work efficiency, and several attempts have been made to improve this.

One of the methods is to spread a solid powder such as talc on the surface of the photosensitive layer immediately before the process of exposing and baking the film plate in close contact with the photosensitive layer (called pakdari/g).53 (10) , 23 (1970) Bengami, Iino, and Printed Information 33 (11), 90 (1973) Ishiyama et al. According to this method, the surface of the photosensitive layer is roughened (matted) by simply scattering solid powder, and a gap is formed between the film original plate and the photosensitive layer, and this gap is used as a passageway in the center. Since the air can be removed, vacuum adhesion can be improved. However, the drawback is that the solid powder simply adheres to the photosensitive layer, so it may fall off during handling, making it impossible to obtain the expected vacuum adhesion, as well as contaminating the surrounding area. On the other hand, when solid powder is dispersed, it scatters and contaminates the air in the plate-making work room and surrounding equipment, causing various problems in the plate-making process, causing work hygiene problems, and even causing damage to the equipment. This has caused various problems in terms of work, such as the fact that it takes a lot of time to clean the items.

Also, JP-A-51-111102 and JP-A No. 52-293
02.

As described in the publications of the above issues, there is a known method of providing a matte layer as the top layer of a photosensitive printing plate, which is removed during development. Compared to the case where no matte layer is provided, this method has the disadvantage that the manufacturing cost is higher due to the addition of coating and drying steps for the matte layer and the need for coating equipment to provide the matte layer. .

Also, JP-A-154-121802 and JP-A No. 55-12
In the technique described in Japanese Patent No. 0034, a photosensitive layer coating composition containing an organic blowing agent is deposited on a support to form a photosensitive layer, and the organic blowing agent is thermally decomposed to form a photosensitive layer. A photosensitive printing plate with a roughened surface of the photosensitive layer has been obtained, but this method requires a heating step after coating the coating composition for the photosensitive column layer, and heating has a negative effect on the performance of the photosensitive layer. It has the disadvantage of having a negative impact.

In order to improve the above-mentioned drawbacks, a suitable fine powder substance is dispersed in a coating liquid containing a photosensitive composition, and a photosensitive printing plate with excellent vacuum adhesion is obtained through a -times coating process. A method was proposed. For example, 1% 1975-124
No. 147, No. 56-156831 and No. 57-115
As described in Japanese Patent No. 548, etc., a photosensitive printing plate containing fine powder particles of plastics such as polystyrene, polyethylene, and thermosetting phenolic resin has been proposed. However, since these plastic fine powder particles are insoluble in the developer, the following problems often occur. That is,
When a large number of such photosensitive printing plates are developed with a tired developer, the fine powder particles remain in the non-image area,
It was found that the photosensitive layer was not removed.

Furthermore, in the technique described in JP-A-56-9739, silica, aluminum oxide, silicon dioxide, etc. are used as fine powder particles to be contained in the photosensitive layer. However, because these fine powder particles are heavy, they tend to settle in a coating solution containing a photosensitive composition, resulting in poor dispersion stability. When a photosensitive printing plate manufactured from such a coating liquid is exposed and developed to obtain a printing plate and printed by a printing press, the area of the halftone dots on the printed matter becomes uneven, and the halftone dots themselves tend to become rough. This is thought to be due to the generation of large particles in the coating solution.

OBJECTS OF THE INVENTION The object of the present invention is to provide a photosensitive printing plate that has improved the drawbacks of the prior art, that is, can be manufactured without additional steps such as a coating step for surface matting, a heating step, etc. An object of the present invention is to provide a photosensitive printing plate having excellent vacuum adhesion, developability, and halftone dot quality.

Structure of the Invention As a result of extensive research, the present inventor has discovered that in a photosensitive printing plate in which a photosensitive composition is layered on a support to form a photosensitive layer,
The photosensitive layer is matted because the photosensitive composition contains a fine powder substance that is insoluble in the layer forming solvent and soluble in the developer (hereinafter referred to as the fine powder ice substance of the present invention). It has been found that the above object can be achieved by a photosensitive printing plate characterized by the following.

The present invention will be explained in detail below.

In the present invention, the fine powder substance of the present invention contained in the photosensitive composition may be any substance as long as it is insoluble in the photosensitive column forming solvent and soluble in the developer. The photosensitive printing plate of the present invention having a photosensitive layer composed of a photosensitive composition containing such a finely powdered substance of the present invention can be produced according to a conventional method. For example, after dissolving the components constituting the photosensitive composition described later in the layer forming solvent described later, the fine powder substance of the present invention is added and dispersed, and the resulting coating solution is applied onto a support and dried. It can be manufactured by

The layer forming solvent in the present invention is usually an organic solvent, such as acetone, methyl ethyl ketone, methyl butyl ketone, tetrahydrofuran, 1,4-dioxane,
Methanol, ethanol, benzene, toluene, xylene, trichlene, N-methylpyrrolidone, dimethylformamide, cyclohexanone, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether.

Ethylene glycol monobutyl ether, acetic acid ester of ethylene glycol monoethyl ether, 4-methoxy-4-methylpentanone-2, methylcarpitol, and a mixed solvent of two or more of these solvents, preferably ethylene glycol monomethyl Ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, acetate ester of ethylene glycol monoethyl ether, methylcarpitol, and mixed solvents of two or more of these solvents.

selected from.

In the fine powder substance of the present invention, the solvent for forming the photosensitive layer is an organic solvent such as the above-mentioned acetone or methylcarpitol, and the developer is an aqueous solution or an aqueous solution containing an alkaline agent as described below. As used in
For example, natural polymer compounds such as gelatin, casein, gum arabic, and alginic acid; monomers containing carboxylic acids (or salts thereof) such as acrylic acid (or salts thereof) and methacrylic acid (or salts thereof); Monomers having sulfonic acid (or its salts) such as sulfonic acid (or its salts) and styrene sulfonic acid (or its salts), for example, having aromatic hydroxyl groups such as hydroxystyrene and N-(hydroxyphenyl) methacrylamide Monomers, for example, synthetic polymer compounds such as homopolymers of monomers having amides such as acrylamide and methacrylamide, or copolymers containing at least one of these heptamers, and the like.

In the above copolymer, a monomer having an amide, a monomer having a carboxylic acid (or a salt thereof), a monomer having a sulfonic acid (or a salt thereof), a monomer having an aromatic hydroxyl group and other Nanatsuma
Any monomer may be used as long as it has an ethylenic double bond that can be copolymerized with these heptamers, but preferably ethylene, flopylene, styrene, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl It is at least 11!1 selected from acrylate and acrylonitrile.

In addition, monomers having an amide, monomers having a carboxylic acid (or its salt), monomers having a sulfonic acid (or its salt), and heptamers having an aromatic hydroxyl group contained in the copolymer may also be used. The amount (9) is 9 or more by mole, preferably 9 or more by mole. Furthermore, the molecular weights of the natural polymer compound and synthetic polymer compound are i, o.
oo~to, ooo, oo.

and preferably 10,000 to 1,000,00
It is 0.

The fine powder substance of the present invention is dispersed in a coating solution, and when the coating solution is coated onto a support to produce a photosensitive printing plate, the surface of the photosensitive layer is matted and image characteristics are improved. In order to obtain a photosensitive printing plate that has excellent vacuum adhesion to the film original plate without causing any adverse effects, it is contained in the photosensitive layer at an appropriate average particle size and in an appropriate amount.

The average particle size is suitably in the range of 1 to 25 μm, preferably in the range of 5 to 20 μm. Such particles are
For example, it can be obtained by finely pulverizing it with a ball mill, jet mill, etc., and then classifying it. Further, the amount added is approximately 0.0% based on the total amount of the photosensitive composition forming the photosensitive layer of the photosensitive printing plate.
0.01% to about 0.01% by weight is suitable, preferably 0.01% to about 0.01% by weight.
．． It ranges from 1 to 10% by weight.

The photosensitive printing plate obtained above has 1
m'' contains 1 to 1000 particles of the fine powder material of the present invention, preferably 5 to 500 particles.

Moreover, this photosensitive printing plate has a vacuum adhesion time that is 30 to 150% shorter than that of a photosensitive printing plate that does not contain the fine powder substance of the present invention in the photosensitive layer.

The coating solution containing the finely powdered substance of the present invention dispersed therein is applied onto a support by various means such as doctor coating, roller coating, bead coating, dip coating, etc., and then dried by evaporating the solvent at room temperature or high temperature. A photosensitive printing plate can be obtained. Immediately before application, the coating solution may be subjected to strong stirring, ultrasonic dispersion, etc. to prevent agglomeration of the fine powdery substances.

The coating thickness of the photosensitive layer after drying of the photosensitive printing plate formed in this way is 0.1 to 71 mm in the case of a photosensitive planographic printing plate.
1/m is suitable, preferably 0.5 to 411/m.

The photosensitive printing plate of the present invention has a photosensitive layer as described below on a support, and a conventionally known plate-like support is used as the support. These are appropriately selected depending on the intended use, method of use, plate type, etc. of the photosensitive printing plate. Examples of materials for this support include paper, plastic (including paper laminated with plastic), metal (
(including paper or plastic with metal vapor-deposited and laminated). Examples of the above-mentioned glass materials include polyethylene, polyethylene terephthalate, polypropylene, polystyrene, polyvinyl acetal, polycarbonate, nitrocellulose, diacetylcellulose, and triacetylcellulose. Further, examples of the metal include aluminum (including alloys), zinc, copper, iron, and the like. Among these, aluminum is preferable when the plate type is a planographic plate, and aluminum, zinc, iron, and polyethylene terephthalate are preferable when the plate type is a letterpress plate. The surface of the support may be treated in advance depending on the plate type, and if the plate type is a lithographic plate, it is subjected to a hydrophilic treatment. This hydrophilic treatment method can be appropriately selected depending on the material of the support surface. When a metal such as aluminum is used as the support surface, roughening treatment, anodizing treatment, immersion in a fluorozirconate aqueous solution,
Preferred methods include immersion in an aqueous silicate solution and immersion in an aqueous phosphate solution. These various hydrophilic treatment methods may be combined; an example is a method in which surface roughening treatment and immersion in a sodium silicate aqueous solution are sequentially performed (described in detail in U.S. Pat. No. 2,714,066). ), a method of sequentially performing a method of immersion in an anodized silicate aqueous solution (described in detail in US Pat. No. 318,146), and the like. On the other hand, when the material of the support surface is plastic, a method known as so-called silver salt photography can be used. For example, electrical discharge treatment, chemical treatment,
Examples include laser treatment and a method of further providing an undercoat layer.

As the photosensitive composition constituting the photosensitive layer provided on the support described above, conventionally known ones can be used. This photosensitive composition contains a photosensitive substance as an essential component, and this photosensitive substance includes those that cause a difference in the solubility of the photosensitive layer in a developer upon exposure, and those that cause intermolecular adhesion before and after exposure. Those that cause a difference in strength, and those that cause a difference in the affinity of the photosensitive layer for water and oil depending on exposure can be used. Typical examples will be explained below.

First, a quinonediazide type positive photosensitive material such as a conventionally known 0-su7toquino/diazide metal product can be mentioned.

The O-quinonediazide compound is a compound having at least one O-quinonediazide group, preferably an O-benzoquinonediazide group or an O-naphthoquinonediazide group, and has various known structures, such as those described in J. Kos@r.
light Sensitive Systems
ohn Wiley & 8onst Inc, 19
This includes compounds described in detail on pages 339 to 353 (published in 1965). Particularly suitable are esters of various hydroxyl compounds and O-naphthoquinonediazide sulfonic acid. Preferred hydroxyl compounds include condensation resins of phenols and carbonyl group-containing compounds, particularly resins obtained by condensation in the presence of an acidic catalyst. Examples of the phenols include phenol, resorcinol, cresol, pyrogallol, and the like. , as the carbonyl group-containing compound, formaldehyde,
Examples include aldehydes such as benzaldehyde and ketones such as acetone.

Especially phenol formaldehyde resin, cresol skewer formaldehyde resin, pyrogallol e acetone resin,
Resorcinol benzaldehyde resin is preferred. Typical specific examples of 0-quinonediazide compounds include benzoquinone-(1,2)-diazide sulfonyl chloride or naphthoquinone-(1°2)-diazide sulfonyl chloride and phenol-formaldehyde resin or cresol-formaldehyde resin. Esther, U.S. Patent No. 3,
Sulfonic acid ester of naphthoquinone-(1°2)-diazide sulfonyl chloride and pyrogallol acetone resin described in JP-A No. 635゜709, JP-A-5
Naphthoquinone-(
a condensate of 1,2)-diazide-(2)-5-sulfonyl chloride and resorcinol-benzaldehyde resin,
Ester compounds of naphthoquinone-(1,2)-diazide-(2)-5-sulfonyl chloride and resorcinol-pyrogallol-acetone copolycondensate described in JP-A-55-76346, and other useful O- Examples of the quinonediazide compound include those obtained by esterifying O-naphthoquinonediazide sulfonyl chloride with a polyester having a hydroxyl group at the terminal described in JP-A-50-117503;
Examples include a homopolymer of p-hydroxystyrene as described in Japanese Patent No. 305, or a copolymer of this and other copolymerizable monomers, which is obtained by subjecting 11Co-naphthoquinonediazide sulfonyl chloride to an esterification reaction. The content of these O-quinonediazide compounds is preferably 5 to 80% by weight, particularly preferably 10 to 80% by weight, based on the total solid content of the photosensitive composition.

Such a quinone diazide type positive photosensitive substance can be used in combination with an alkali-soluble resin as a binder, if necessary. As the alkali-soluble resin, those obtained by combining phenols and ketones or aldehydes in the presence of an acidic catalyst are preferred. Examples of the phenols include phenol, cresol, and p-substituted phenol. Examples of the aldehydes include acetaldehyde, formaldehyde, etc.
Formaldehyde is preferred. Acetone is preferred as the ketone.

Preferred alkali-soluble resins include, for example, phenol-formaldehyde resin, cresol-formaldehyde resin, phenol-cresol-formaldehyde copolycondensate resin described in JP-A-55-57841, and ``JP-A-55-127553''. Copolycondensate resins of p-substituted phenol and phenol or cresol and formaldehyde as described in publications, resorcinol-benzaldehyde resins, pyrogallol-
Examples include condensates of polyhydric phenols and benzaldehyde such as benzaldehyde resins, copolycondensates of polyhydric phenols and acetone such as pyrogallol-resorcinol-acetone resins, and xylenol-formaldehyde resins.

The content of these alkali-soluble resins is preferably from 50 to 90% by weight, particularly from 50 to 90% by weight, based on the total solid content of the photosensitive composition.
85% by weight is preferred.

As a solvent for forming a layer of a photosensitive composition using a quinonediazide type compound as a photosensitive substance, a single or mixed solvent of ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoethyl ether acetate, methyl calpitol, etc. is used. be able to.

Another photosensitive material that can be used is a diazo resin typified by a condensate of an aromatic diazonium salt and formaldehyde. Particular preference is given to salts of condensates of p-diazodiphenylamine and formaldehyde or acetaldehyde, such as reaction products of hexafluorophosphates, tetrafluoroborates, perchlorates or periodates with the above condensates. Certain diazo resin inorganic salts and U.S. Patent Nos. 3 and 3
Examples include diazo resin organic salts, which are reaction products of the above condensates and sulfonic acids, as described in No. 00,309. Diazo resins are used with preferred binders. Various polymeric compounds can be used as such a binder, but preferred are those described in JP-A-54-98.
A monomer having an aromatic hydroxyl group as described in Japanese Patent No. 613, such as N-(4-hydroxyphenyl)
Acrylamide, N-(4-hydroxyphenyl)methacrylamide, o-, m+, or p-hydroxystyrene, o+.

Copolymer of m + or p-hydroxyphenyl methacrylate and other monomers, US Pat. No. 4,123゜2
Polymers containing hydroxyethyl acrylate units or hydroxyethyl methacrylate units as a main repeating unit as described in No. 76, natural resins such as shellac and rosin, polyvinyl alcohol, U.S. Pat. No. 3,751,257 linear polyurethane resins as described in U.S. Pat. No. 3,660,097, phthalated resins of polyvinyl alcohol, epoxy resins condensed from bisphenols and epichlorohydrin, cellulose acetate. , celluloses such as cellulose acetate phthalate.

Solvents for layering photosensitive materials and photosensitive compositions containing diazo resins include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoethyl ether acetate, and methyl calpitol alone or in combination. etc. can be used.

The working solution in the present invention may vary depending on the type of photosensitive composition used in the photosensitive printing plate, but preferably contains at least one alkaline agent.

Examples of alkali agents include sodium silicate, potassium silicate, lithium silicate, sodium hydroxide, potassium hydroxide, lithium hydroxide, ammonium hydroxide, tribasic sodium phosphate, dibasic sodium phosphate, tribasic potassium phosphate, Inorganic alkaline agents, such as potassium diphosphate, tertiary ammonium phosphate, ammonium diphosphate, sodium metasilicate, sodium bicarbonate, sodium carbonate, potassium carbonate, ammonium carbonate, etc.; Organic amine compounds such as no-, di-, or trimethylamine, mono-, di-, or triethylamine, mono-1- or di-isopropylamine, n-butylamine, mono-, di-, or triisopropylamine, ethyleneimine, ethylenediimine, etc. Can be mentioned.

Especially when the photosensitive layer contains a negative-type diazo compound (
Hereinafter, this will be referred to as a negative type shear PS version. ), the liquid solution is preferably an alkaline aqueous solution containing an organic solvent, and the organic solvent has a solubility in water of 10% by weight or less at 20'C.
This is preferable in terms of improving the developability, ink receptivity, and water retention of the S plate. Examples of organic solvents having a solubility in water of 10% by weight or less at 20°C include, for example, ethyl acetate, globyl acetate, butyl acetate, amyl acetate, benzyl acetate, ethyl acetoacetate, ethylene glycol monobutyl acetate, Carboxylic acid esters such as ethyl malonate, butyl lactate, butyl levulinate, ethyl butyl ketone, methyl isobutyl ketone, ketones such as cyclohexanone, ethylene glycol motuptyl ether, ethylene glycol, monophthyl phenyl ether, ethylene glycol mono-benzyl ether, ethylene glycol mono-n-hexyl ether, ethylene glycol mono-phenyl ether, propylene glycol mono-phenyl ether, benzyl alcohol, ethoxyethoxyethanol, methylphenyl carbinol, n-amyl alcohol, methyl amyl alcohol, 4
-Alcohols such as phenyl-1-butanol, β-7enethyl alcohol, 3-phenyl-1-7'' lobanol, alkyl-substituted aromatic hydrocarbons such as xylene, methylene dichloride, ethylene dichloride, monochlorobenzene, etc. and halogenated hydrocarbons.

One or more of these organic solvents may be used. Among these organic solvents, ethylene glycol monophenyl ether and pendyl alcohol are effective. Further, the content of these organic solvents in the developer is preferably 1. -20% by weight, especially 2 to 10% by weight to obtain more preferable results.

Further, the preferable content of the alkaline agent contained in the developer for the negative diazo PS plate is 0.05 to 4% by weight, preferably 0.5 to 2% by weight.

Further, it is preferable to contain an anionic surfactant, a water-soluble sulfite, a solubilizer, etc. in the developer of the negative-working diazo PS plate in order to improve the developability. Examples of the anionic surfactant include higher alcohol sulfate esters, aliphatic alcohol phosphate ester salts, alkylaryl sulfonates, alkylamides sulfonates, and dibasic fatty acids described in JP-A No. 57-5045. Examples include ester sulfonates, alkylnaphthalene sulfonates, and formaldehyde condensates of alkylnaphthalene sulfonates. Among these, sodium butylnaphthalene sulfonate and a formaldehyde condensate of sodium butylnaphthalene sulfonate are particularly preferred because they have a strong separation and solubility from the hydrophilic surface of the photosensitive layer during development.

The content of these anionic surfactants in the developer component is preferably 0.5 to 10% by weight, more preferably 1 to 5% by weight.

Water-soluble sulfites have the effect of preventing the photosensitive composition from sticking or remaining on hydrophilic surfaces due to side reactions and improving developability. Specific examples include alkali or alkaline earth metal salts of sulfites. Preferred examples include sodium sulfite, potassium sulfite, lithium sulfite, and magnesium sulfite.

The preferred content of sulfite in the developer composition is 0.
．． 05-4% by weight, more preferably 0.1-1% by weight
It is.

The solubilizer has a solubility of 10% in water at 20'C as mentioned above.
Since it assists the dissolution of the following organic solvents, it is preferable to use an organic solvent that is more easily soluble in water, and it is preferable to use low-molecular alcohols, ketones, and lactams.

Specifically, for example, methanol, ethanol, gropanol, butanol, acetone, methyl ethyl ketone, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, methoxybutanol, ethoxybutanol, 4-methylbutanol,
N-methylpyrrolidone and the like are preferred. The amount of solubilizer used is preferably at most (9)% by weight in the developer.

In addition, when a photosensitive composition containing a positive type diazo compound is provided on the hydrophilic surface of the support (hereinafter referred to as positive type diazo compound),
It is written as S version. ), the developer is preferably an alkaline aqueous solution, and the alkaline agents are preferably potassium silicate, lithium silicate, sodium silicate, sodium hydroxide, potassium hydroxide, lithium hydroxide, tribasic sodium phosphate, Examples include sodium diphosphate, potassium triphosphate, potassium diphosphate, sodium carbonate, potassium carbonate, and the like. Among these, potassium silicate,
A developer containing an alkali silicate such as lithium silicate or sodium silicate is most preferable because it has good scratch gradation, and the composition of the alkali silicate is [slo,]/ in terms of moA/ratio.
[M] = 0.5 ~ 1.5 (Kokoni (5iOt), C
M) indicate the molar concentration of sto and the molar concentration of total alkali metals, respectively. ), and StO, is 0.8 to 8
% by weight is preferably used. Of this alkali silicate composition, especially in molar ratio (Sly, )/
(M] = 0.5 to 0.75, and Sin is 0
．． A developer with a concentration of 8 to 4% by weight is preferably used because it is easy to neutralize the developer waste solution due to its low concentration, while a developer with a molar ratio of more than 0.75 and up to 1.3 and an SSO of 1 to 1. 8
% by weight developer is preferably used because it has a high buffering power and a high processing ability.

In addition, in the developer of positive type diazo 28 plate, JP-A-50-
By containing at least one of an anionic surfactant and an amphoteric surfactant as described in JP-A-51324, or as described in JP-A-55-95946 and JP-A-56-142528. When a polymer electrolyte is contained, the wettability to the photosensitive composition can be improved and the gradation can be further improved, and it is preferably used.

The amount of such surfactant added is not particularly limited, but 0.0
0.03 to 3% by weight is preferred, especially 0.006 to 1% by weight
A concentration of is preferred. Further, it is preferable that the alkali silicate contains 4 mol% or more of potassium as the alkali metal in all the alkali metals, since the generation of insoluble matter in the developer is small, and more preferably 90 mol% or more of potassium. , most preferably when the potassium content is 100 mol %.

Regardless of whether the photosensitive composition is negative or positive, the developer in the present invention may contain an antifoaming agent. Suitable antifoaming agents include organosilane compounds.

Various conventionally known methods can be used to develop the photosensitive printing plate that has been imagewise exposed with the developer described above. Specifically, a method in which an imagewise exposed photosensitive printing plate is immersed in a developer, a method in which a developer is jetted from a number of nozzles onto the photosensitive layer of the photosensitive printing plate, and a sponge moistened with a developer is used. Examples include a method of wiping the photosensitive layer of the photosensitive printing plate with water, a method of applying a developer to the surface of the photosensitive layer of the photosensitive printing plate with a roller, and the like. Alternatively, after applying a developer to the photosensitive layer of the photosensitive printing plate by 5&C, the surface of the photosensitive layer may be lightly rubbed with a brush or the like.

The developing conditions can be appropriately selected depending on the developing method. - For example, in a developing method by immersion, a method of immersing in a developer of about 10-35 T for about 10 to 80 seconds is selected.

EXAMPLES Examples of the present invention are shown below, but the present invention is not limited thereto.

Example 1 An aluminum plate was immersed in a 20% aqueous solution of sodium phosphate to defat it, roughened by electrolytic etching, anodized in a sulfuric acid solution, and then immersed in a sodium silicate solution to seal it. Hole treatment was performed. A photosensitive solution having the following composition was applied onto this aluminum plate using a spin coating machine, and
It was dried at ℃ for 3 minutes to obtain a photosensitive planographic printing plate. The coating amount after drying was 2.79/ze.

Esterified product of naphthoquinone-(1,2)-diazide-5-sulfo/acid chloride and m-cresol formaldehyde resin (condensation rate 5 mol%)
3.5 gm-cresol mat formaldehyde resin
8.0g naphthoquinone-(1,2)-diazido-4-sulfonic acid chloride 0.15g esterified product of p-octylphenol formaldehyde resin and naphthoquinone-(1,2)-diazide-5-sulfonic acid chloride (mol% of condensed groups ) 0.1
2g gelatin (average particle size 10μm) 0
．． 06g Oil Blue #603 (manufactured by Orient Kagaku Kogyo Co., Ltd.) 0.2g ethylene glycol monoethyl ether 100g Among the above compositions, gelatin is the fine particle material of the present invention, which is crushed in a ball mill and then pulverized in a classifier (alpime zigzag). The particles were classified using a classifier) and those having an average particle size of 10 tones were used.

The photosensitive planographic printing plate (1003x
A positive original was attached to the photosensitive layer (800 va) using a vacuum adhesion method, and exposed for 80 seconds from a distance of 1 m using a 2 Kw metal noride lamp (Idolfin 2000 manufactured by Iwasaki Electric Co., Ltd.) as a light source. , and was immersed in a 4% by weight aqueous sodium metasilicate solution and developed at 5° C. for 45 seconds to obtain a lithographic printing plate. Then, when this printing plate was printed on an offset printing machine, many printed matter with clear images were obtained.

Example 2 In Example 1, instead of gelatin 0.0611, gum arabic (average particle size 16 μm) 0.1. A photosensitive lithographic printing plate was obtained in the same manner as in Example 1 except that p was used.

Exposure, development, and printing were carried out in the same manner as in Example 1, and the same results as in Example 1 were obtained.

Example 3 Photosensitization was carried out in the same manner as in Example 2, except that polyacrylamide (200:000 in Mn, average particle size 13 μm) o, os g was used instead of gum arabic 0.1.9 in Example 2. A lithographic printing plate was obtained, and then exposed, developed and printed in the same manner as in Example 2. As a result, Example 2
obtained similar results.

Example 4 Example 3 except that polymethacrylic acid (400,000 in Mn, average particle size 13 μm) 0.0129 was used instead of polyacrylamide 0.05.9.
A photosensitive lithographic printing plate was obtained in the same manner as in Example 2, and then exposed, developed and printed in the same manner as in Example 2. As a result, the same results as in Example 2 were obtained.

Example 5 An aluminum plate was immersed in a 20% aqueous solution of sodium phosphate to degrease it, roughened by electrolytic etching, anodized in a sulfuric acid solution, and then immersed in a sodium silicate solution for sealing. processed. A photosensitive solution having the following composition was applied onto this aluminum plate using a spin coating machine, and
It was dried at ℃ for 3 minutes to obtain a photosensitive planographic printing plate. The coating amount after drying was 2.011/ze.

(Photosensitive liquid composition) Copolymer A 5.09 Diazo resin B O,5Ii Polyhalastyrene sulfonic acid (150,000 average particle size t6 am in Mn) O-03,l
i' sherry r -AC-10L
O-11 (manufactured by Nippon Junyaku Co., Ltd.) Victoria Pipe Blue BOHO, 1,9 (manufactured by Hodogaya Chemical Co., Ltd.) Ethylene glycol monomethyl ether 100
m1 (coating solvent) However, the above copolymer A has a molar ratio of p-hydroxyphenyl methacrylamide/acrylonitrile/ethyl acrylate/methacrylic acid = 10/30/60/6
The composition was dissolved in methyl selon, heated at 65°C for 10 hours in a sealed tube purged with nitrogen, and after the reaction was completed, the reaction solution was poured into water with stirring, and the resulting white precipitate was filtered and dried. It is. Diazo resin B is 5% by weight of diazo resin (trade name E) at room temperature.

H, C Co., Ltd. D-012) aqueous solution and 10% by weight
This is a hexafluorophosphate obtained by mixing an aqueous ammonium hexafluorophosphate solution, absorbing and filtering the resulting precipitate, and drying under reduced pressure at 30 to 40°C. The weight average molecular weight of the copolymer was so, ooo, and the molecular weight distribution of the diazo resin was measured using gel permeation cell chromatography (GPC) K, and it was found that 93 mol% of the total was pentamer or less. .

Polyparastyrene sulfonic acid (fine particulate material of the present invention) was pulverized with a ball mill and classified with a classifier (zigzag classifier manufactured by Albime), and had an average particle size of 161 Irn. A negative original film was adhered to the photosensitive layer of the photosensitive lithographic printing plate thus obtained by a vacuum adhesion method, and then
Exposure was performed for 42 seconds from a distance of 1 m using a Kv metal halide lamp as the light source, and the developer was heated at 5°C with a developer having the following composition.
It was developed for 45 seconds to obtain a lithographic printing plate.

(Developer composition) Ethylene glycol phenyl ether 1609 diethanolamine 7'0.9 = Pionin A-44B 50/i (manufactured by Takemoto Yushi Co., Ltd.) Water
780. Then, when this printing plate was printed on an offset printing machine, many printed matter with clear image scratches were obtained.

Example 6 In Example 5, polyparastyrene sulfonic acid 0.0
3. Polyethylene sulfonic acid (Zo in Mn) instead of 90
A photosensitive lithographic printing plate was obtained in the same manner as in Example 5, except that 0.021 was used, and then KL-C exposure, development and printing were carried out in the same manner as in Example 5. As a result, the same results as in Example 5 were obtained.

Comparative Example 1 A photosensitive lithographic printing plate was obtained in the same manner as in Example 1, except that silica gel (average particle diameter 10 μm) was used instead of gelatin (average particle diameter LoIIm).

Example 1 The photosensitive planographic printing plate obtained at 5VcL was
Exposure and development were carried out in the same manner as above to obtain a lithographic printing plate. When this printing plate was then printed using an offset printing machine K, the halftone dot area was uneven and the shape of the halftone dots was rough. This is probably because the dispersion stability of the photosensitive liquid was poor and large particles were generated.

Comparative Example 2 A photosensitive lithographic printing plate was obtained in the same manner as in Comparative Example 1 except that alumina (average particle size ls tan ) was used instead of silica gel (average particle size 10 μm),
Exposure and development were performed in the same manner as in Comparative Example 1 to obtain a lithographic printing plate. Then, when this printing plate was printed on an offset printing machine, the halftone dot area was uneven.1. The shape of the halftone dots was rough. This is probably because the dispersion stability of the photosensitive liquid was poor and large particles were produced due to aggregation.

Comparative Example 3 A photosensitive lithographic printing plate was obtained in the same manner as Comparative Example 2 except that polystyrene (average particle size 10 tan ) was used instead of alumina (average particle size 161 nn). Exposure and development were carried out in the same manner to obtain a lithographic printing plate.

When this lithographic printing plate was carefully observed with a 5x magnifying glass, polystyrene particles remained in the non-image areas among the halftone dots.

Furthermore, when the photosensitive planographic printing plate obtained in Example 1 and the photosensitive planographic printing plate described above were developed using the developer 1j used in Example 1, the latter showed a Particles that appeared to be polystyrene remained in the image area, and when developing ink (spo-i, manufactured by Konishiroku Photo Industry Co., Ltd.) was applied, there was no need to add ink to that area in the same manufacturing process, and conventional technology was used. There is no deterioration in developability (incomplete removal of the photosensitive layer) or deterioration in halftone dot quality caused by the application of technical means to make the surface matte as seen in .

Claims (1)

[Claims] In a photosensitive printing plate in which a photosensitive layer is formed by depositing a photosensitive composition on a support, the photosensitive composition is a fine powder that is insoluble in a layer-forming solvent and soluble in a developer. A photosensitive printing plate characterized by containing a substance similar to the above.