JP5192966B2 - Planographic printing plate making method - Google Patents

Description

  The present invention relates to a method for making a lithographic printing plate.

In general, a lithographic printing plate comprises an oleophilic image area that receives ink in the printing process and a hydrophilic non-image area that receives dampening water. Lithographic printing uses the property that water and printing ink repel each other, so that the oleophilic image area of the lithographic printing plate is the ink receiving area, the hydrophilic non-image area is dampened with the water receiving area (ink non-receiving area). ), A difference in ink adhesion is caused on the surface of the lithographic printing plate, and after ink is applied only to the image area, the ink is transferred to a printing medium such as paper and printed.
In order to produce this lithographic printing plate, a lithographic printing plate precursor (PS plate) in which an oleophilic photosensitive resin layer (photosensitive layer, image forming layer) is provided on a hydrophilic support has been widely used. Yes. Usually, the lithographic printing plate precursor is exposed through an original image such as a lithographic film, and then the portion that becomes the image portion of the image forming layer is left, and the other unnecessary image forming layer is washed with an alkaline developer or organic A lithographic printing plate is obtained by dissolving and removing with a solvent and exposing the surface of the hydrophilic support to form a non-image area.

  As described above, in the plate making process of a conventional lithographic printing plate precursor, a step of dissolving and removing an unnecessary image forming layer with a developer or the like is necessary after exposure, but it is closer to a neutral range in terms of environment and safety. Treatment with a developing solution and a small amount of waste liquid are cited as problems. In particular, in recent years, disposal of waste liquid discharged with wet processing has become a major concern for the entire industry due to consideration for the global environment, and the demand for solving the above-mentioned problems has become stronger.

  On the other hand, in recent years, digitization technology for electronically processing, storing, and outputting image information by a computer has become widespread, and various new image output methods corresponding to such digitization technology will be put into practical use. It is becoming. Along with this, digitized image information is carried by high-convergence radiation such as laser light, and the lithographic printing plate precursor is scanned and exposed with that light, directly without using a lithographic film. Computer-to-plate (CTP) technology has been attracting attention. Therefore, obtaining a lithographic printing plate precursor adapted to such a technique is one of the important technical issues.

As mentioned above, the low alkali level of the developer and the simplification of the processing process are more strongly desired than ever in terms of consideration for the global environment, space saving, and low running cost. It has become to.
For example, Patent Document 1 describes a developing method in which processing is performed with an aqueous solution having a pH of 8.5 to 11.5.
Moreover, in the Example of patent document 2, 1 bath process by the process liquid containing the water-soluble resin of pH 11.9-12.1 is described.
Patent Document 3 describes a lithographic printing plate suitable for scanning exposure with an infrared laser.

JP-A-11-65126 European Patent Application No. 1868036 JP 2007-12121450 A

As described above, the conventional development processing step generally involves three steps of developing with an alkaline aqueous solution having a pH of 10 or more, then flowing an alkaline agent in a washing bath, and then processing with a gum solution mainly composed of a hydrophilic resin. For this reason, the automatic developing machine itself takes up a large space, and there are still problems in terms of environment and running cost, such as a problem of developing waste liquid, washing waste liquid, and gum waste liquid.
In patent document 1, the water-washing and gum solution processing process is required, and it has not led to the solution of the problem of an environmental and running cost side.
Further, in Patent Document 2, the original plate with pH 12 alkali attached to the plate surface has a problem in terms of safety to the operator, and the image portion gradually dissolves as time elapses after printing the original plate until printing. There was a problem that caused a decrease in printing durability and chemical resistance.
Furthermore, in Patent Document 2, since the gum solution treatment step is not performed, the surface protection function is poor, that is, the non-image part is easily soiled by an external factor, and in particular, the non-image part of the developed plate is removed. Print stains (hereinafter also referred to as “fingerprint trace stains”) that occur when held with bare hands have been a problem.
Further, in Patent Document 3, waste is likely to be generated in the developer, and processing performance at the time of development is inferior. Therefore, replenishment of the developer is necessary in a fast cycle, leading to solving environmental and running cost problems. Not in.

An object of the present invention is to solve the above problems and achieve the following object.
That is, an object of the present invention is to provide a plate making method of a lithographic printing plate that is excellent in printing durability and processability during development and can suppress fingerprint trace stains.

The above-described problems of the present invention have been solved by the means described in <1> below. It is described below together with <2> to <10> which are preferred embodiments.
<1> On a support, (A) a radical generator, (B) a polymer having a phenyl group substituted with a vinyl group in a side chain, (C) a compound having two or more phenyl groups substituted with a vinyl group, And (D) an exposure process in which a lithographic printing plate precursor having a photosensitive layer containing an infrared absorber is image-exposed, and removal of the photosensitive layer in the non-exposed area by a processing solution having a pH of 8.5 to 10.8. And a plate-making method of a lithographic printing plate, comprising a one-liquid treatment step in which the plate surface hydrophilization treatment is performed with one liquid,
<2> The plate making method of a lithographic printing plate as described in <1> above, wherein the treatment liquid is an aqueous solution containing a buffer and a surfactant and / or a water-soluble polymer compound,
<3> The plate-making method of a lithographic printing plate as described in <2> above, wherein the buffer contains a carbonate,
<4> The lithographic printing plate making method according to any one of the above <1> to <3>, wherein the pH of the treatment liquid is 8.5 or more and less than 10.0,
<5> The plate-making method of a lithographic printing plate according to any one of the above <1> to <4>, wherein the treatment liquid contains hydroxycarboxylic acid ions,
<6> The plate making method of a lithographic printing plate according to <5>, wherein the hydroxycarboxylic acid is a hydroxycarboxylic acid having two or more carboxyl groups,
<7> The lithographic printing plate according to <5> or <6>, wherein the hydroxycarboxylic acid ion is at least one ion selected from the group consisting of citrate ion, tartrate ion and malate ion. Plate making method,
<8> The lithographic printing plate according to any one of <1> to <7>, wherein the polymer (B) having a phenyl group substituted with a vinyl group in the side chain further has an acid group in the side chain. Plate making method,
<9> The plate making method of a lithographic printing plate according to <8>, wherein the acid group is a carboxyl group,
<10> The plate making method of a lithographic printing plate as described in any one of the above <1> to <9>, wherein the water washing step is not performed before and after the one-liquid treatment step.

  ADVANTAGE OF THE INVENTION According to this invention, the plate-making method of the lithographic printing plate which is excellent in printing durability and the processability at the time of image development, and can suppress a fingerprint trace stain can be provided.

  Hereinafter, the present invention will be described in detail.

The plate making method of the lithographic printing plate of the present invention comprises: (A) a radical generator, (B) a polymer having a phenyl group substituted with a vinyl group in a side chain, and (C) a phenyl substituted with a vinyl group. A compound having two or more groups, and (D) an exposure process for image exposure of a lithographic printing plate precursor having a photosensitive layer containing an infrared absorber, and a treatment liquid having a pH of 8.5 to 10.8. It includes a one-liquid processing step in which the photosensitive layer in the non-exposed portion is removed and the plate surface is made hydrophilic by one liquid.
Moreover, it is preferable that the plate-making method of the lithographic printing plate of this invention does not perform a water washing process before and after the said 1 liquid process process.

(Lithographic printing plate precursor)
The lithographic printing plate precursor that can be used in the present invention comprises (A) a radical generator, (B) a polymer having a phenyl group substituted with a vinyl group in a side chain, and (C) a vinyl group substituted on a support. And a photosensitive layer containing (D) an infrared absorber. Moreover, you may further have other layers, such as an intermediate | middle layer (undercoat layer) as needed.
Further, the lithographic printing plate precursor that can be used in the present invention may have a protective layer (hereinafter also referred to as “overcoat layer”), but preferably does not have a protective layer. By having the photosensitive layer having the above structure, it is possible to sufficiently cure without providing a protective layer for preventing the influence of oxygen in the atmosphere.
Hereinafter, each element constituting the lithographic printing plate precursor according to the invention will be described.

<Photosensitive layer>
The photosensitive layer in the lithographic printing plate precursor that can be used in the lithographic printing plate making method of the present invention comprises (A) a radical generator, (B) a polymer having a phenyl group substituted with a vinyl group in the side chain, (C A) a monomer having two or more phenyl groups substituted by vinyl groups, and (D) an infrared absorber.
The lithographic printing plate precursor that can be used in the present invention is a negative lithographic printing plate precursor, and the photosensitive layer is a negative recording layer (hereinafter, “photosensitive layer” is referred to as “negative recording layer”). Also called.)

The photosensitive layer has an image portion forming mechanism as described below.
That is, (D) infrared rays absorbed by the infrared absorber are converted into heat, and radicals are generated from the (A) radical generator by the heat and / or light generated at this time. Then, with the generated radical as an initiator, a polymerization reaction of a monomer having (C) two or more phenyl groups substituted with vinyl groups occurs in a chain and is cured. In addition, since (B) a polymer having a phenyl group substituted with a vinyl group in the side chain is used as the binder polymer, a styryl radical is generated by the radical generated from the component (A), and the styryl radical is recombined with each other. In order to effectively crosslink, the formed film has a hydrophobic property and has a function of being able to form a cured film with excellent characteristics because it can obtain a surface excellent in development resistance. Yes.
For these reasons, the photosensitive layer containing such components (A) to (D) can achieve high sensitivity by combining (A) a radical generator and (D) an infrared absorber. In addition, it can be cured sufficiently without providing an overcoat layer that prevents the influence of oxygen in the atmosphere, and there is no need to perform heat treatment after exposure.
Hereinafter, each component contained in the photosensitive layer will be sequentially described.

[(A) Radical generator (compound that generates radicals by light or heat)]
The compound that generates radicals by light or heat that can be used in the present invention (hereinafter, also referred to as “radical generator” as appropriate) is any compound that can generate radicals by light or heat. Can be used.
Examples of the radical generator include organic boron salts, onium salt compounds, trihaloalkyl-substituted compounds (for example, trihaloalkyl-substituted nitrogen-containing heterocyclic compounds such as s-triazine compounds, oxadiazole derivatives, trihaloalkylsulfonyls). Compound)), hexaarylbisimidazole, titanocene compound, ketoxime compound, thio compound, organic peroxide and the like.
In the present invention, among these radical generators, it is particularly preferable to use an organic boron salt or a trihaloalkyl-substituted compound, and it is more preferable to use a combination of an organic boron salt and a trihaloalkyl-substituted compound.

  The organoboron anion constituting the organoboron salt is preferably represented by the following formula (1).

In the formula (1), R ¹¹ , R ¹² , R ¹³ and R ¹⁴ may be the same or different, and may be an alkyl group, aryl group, aralkyl group, alkenyl group, alkynyl group, cycloalkyl group, Or, it represents a heterocyclic group. Of these, it is particularly preferred that one of R ¹¹ , R ¹² , R ¹³ and R ¹⁴ is an alkyl group and the other substituent is an aryl group.

The organoboron anion is present simultaneously with the cation that forms a salt with it. Examples of the cation in this case include alkali metal ions, onium ions, and cationic sensitizing dyes.
Examples of the onium ions include ammonium ions, sulfonium ions, iodonium ions, and phosphonium ions.
When a salt of an organic boron anion and an alkali metal ion or onium ion is used as the organic boron salt, a dye is added by adding a sensitizing dye (in the present invention, (D) an infrared absorber). The photosensitivity in the wavelength range of the light absorbed by is performed. Further, when a salt having an organic boron anion as a counter anion of a cationic sensitizing dye is used as the organic boron salt, photosensitivity is imparted according to the absorption wavelength of the cationic sensitizing dye. However, in the latter case, it is preferable to further contain a salt of an alkali metal ion or onium ion and an organic boron anion.

The organic boron salt used in the present invention is a salt containing an organic boron anion represented by the above formula (1), and alkali metal ions and onium ions are preferably used as cations forming the salt. Particularly preferred examples are salts of organic boron anions and onium ions, specifically, ammonium salts such as tetraalkylammonium salts, sulfonium salts such as triarylsulfonium salts, and phosphonium salts such as triarylalkylphosphonium salts. Can be mentioned.
Specific examples (BC-1) to (BC-6) of particularly preferred organic boron salts are shown below.
In the following specific examples, Me represents a methyl group, n-Bu represents an n-butyl group, Ph represents a phenyl group, and t-Bu represents a t-butyl group.

  In the present invention, other preferred radical generators include trihaloalkyl-substituted compounds. Specifically, the trihaloalkyl-substituted compound is a compound having at least one trihaloalkyl group such as a trichloromethyl group or a tribromomethyl group in the molecule. As a preferable example, the trihaloalkyl group is a nitrogen-containing compound. Examples of the compound bonded to the heterocyclic group include s-triazine derivatives and oxadiazole derivatives, or a trihaloalkylsulfonyl compound in which the trihaloalkyl group is bonded to an aromatic ring or a nitrogen-containing heterocyclic ring via a sulfonyl group. Can be mentioned.

  Particularly preferred specific examples (T-1) to (T-15) of compounds in which a trihaloalkyl group is bonded to a nitrogen-containing heterocyclic group, and particularly preferred specific examples (BS-1) to (BS-) of trihaloalkylsulfonyl compounds. 10) is shown below. In the specific examples below, Me represents a methyl group.

Moreover, in this invention, an onium salt compound is mentioned as another preferable radical generating agent. As the onium salt compound, a sulfonium salt, an iodonium salt, or a diazonium salt is preferably used. For example, the sulfonium salts described in paragraphs 0043 to 0048 of JP-A No. 2004-252284 and the iodonium salts described in paragraphs 0050 to 0058 may be mentioned.
In particular, the oxime ester compound, diazonium salt, iodonium salt, and sulfonium salt are preferable in terms of reactivity and stability. In the present invention, these onium salts function not as acid generators but as ionic radical polymerization initiators.
In the present invention, a particularly preferred polymerization initiator is an iodonium salt having an electron donating group or a sulfonium salt having an electron withdrawing group from the balance of reactivity and stability. Most preferred is an iodonium salt having 2 or more, more preferably an iodonium salt having 3 or more alkoxy groups. Examples thereof include iodonium salts described in paragraphs 0048 to 0068 of JP-A-2008-107758.

  In the present invention, other preferable radical generators include organic peroxides. Examples of the organic peroxide include cumene hydroperoxide, t-butyl hydroperoxide, dichloroperoxide, di-t-butyl peroxide, benzoyl peroxide, acetyl peroxide, lauroyl peroxide, and compounds having the structure shown below. Etc.

  The content of the radical generator (A) as described above may be included in the range of 1 to 100% by weight with respect to the polymer having (B) a phenyl group substituted with a vinyl group in the side chain, which will be described later. Preferably, it is contained in the range of 1 to 40% by weight.

  As the radical generator (A) that can be used in the present invention, only one type may be used, or two or more types may be used in combination. When used in combination, the total amount of the radical generator is preferably contained in the range of 1 to 100% by weight based on the polymer having (B) a vinyl group-substituted phenyl group in the side chain, which will be described later. More preferably, it is contained in the range of 40% by weight.

[(B) Polymer having phenyl group substituted by vinyl group in side chain (binder polymer)]
In the photosensitive layer, a polymer having a phenyl group substituted with a vinyl group in a side chain (hereinafter, also referred to as “specific polymer” as appropriate) used as a binder polymer is a phenyl group substituted with a vinyl group. It is bonded to the main chain directly or through a linking group.
The binder polymer preferably has a molecular weight or weight average molecular weight of 1,500 or more, and more preferably 2,000 or more.
The linking group is not particularly limited, and includes an arbitrary group, an atom, or a complex group thereof.
The phenyl group may be substituted with a substitutable group or atom in addition to the vinyl group.
Specific examples of the substitutable group or atom include a halogen atom, a carboxy group, a sulfo group, a nitro group, a cyano group, an amide group, an amino group, an alkyl group, an aryl group, an alkoxy group, and an aryloxy group. Can be mentioned.
Furthermore, the vinyl group may be substituted with a halogen atom, a carboxy group, a sulfo group, a nitro group, a cyano group, an amide group, an amino group, an alkyl group, an aryl group, an alkoxy group, an aryloxy group, or the like.
More specifically, the polymer having a phenyl group substituted with a vinyl group in the side chain is preferably a polymer having a group represented by the following formula (2) in the side chain.

In formula (2), Z ¹ represents a linking group, and R ¹ , R ² , and R ³ each independently represent a hydrogen atom, a halogen atom, a carboxy group, a sulfo group, a nitro group, a cyano group, an amide group, an amino group. Represents a group, an alkyl group, an aryl group, an alkoxy group, an aryloxy group or the like, and these groups are substituted with an alkyl group, an amino group, an aryl group, an alkenyl group, a carboxy group, a sulfo group, a hydroxy group, or the like. Also good.
R ⁴ represents a substitutable group or atom.
n represents 0 or 1, m ¹ represents an integer of 0 to 4, and k ¹ represents an integer of ¹ to 4.

The group represented by formula (2) will be described in more detail.
As the linking group represented by Z ¹ , an oxygen atom, a sulfur atom, an alkylene group, an alkenylene group, an arylene group, —N (R ⁵ ) —, —C (O) —O—, —C (R ⁶ ) = Examples include N-, -C (O)-, a sulfonyl group, groups shown below, and a group in which two or more such as heterocyclic structures are combined. Here, R ⁵ and R ⁶ represent a hydrogen atom, an alkyl group, an aryl group, or the like. The above linking group may further have a substituent such as an alkyl group, an aryl group, or a halogen atom.

The heterocyclic structure constituting the linking group represented by Z ¹ includes pyrrole ring, pyrazole ring, imidazole ring, triazole ring, tetrazole ring, isoxazole ring, oxazole ring, oxadiazole ring, isothiazole ring, thiazole ring , Thiadiazole ring, thiatriazole ring, indole ring, indazole ring, benzimidazole ring, benzotriazole ring, benzoxazole ring, benzthiazole ring, benzselenazole ring, benzothiadiazole ring, pyridine ring, pyridazine ring, pyrimidine ring, pyrazine ring , Nitrogen-containing heterocycles such as triazine ring, quinoline ring and quinoxaline ring, furan ring and thiophene ring. These heterocyclic structures may further have a substituent such as an alkyl group, amino group, aryl group, alkenyl group, carboxy group, sulfo group or hydroxy group.

Examples of the substitutable group or atom represented by R ⁴ include a halogen atom, a carboxy group, a sulfo group, a nitro group, a cyano group, an amide group, an amino group, an alkyl group, an aryl group, an alkoxy group, and an aryloxy group. Is mentioned. Furthermore, these groups or atoms may have a substituent such as an alkyl group, an amino group, an aryl group, an alkenyl group, a carboxy group, a sulfo group, or a hydroxy group.

  Specific examples (K-1) to (K-20) of the groups represented by the formula (2) are shown below, but are not limited to these specific examples.

Among the groups represented by the formula (2), those having the following structure are preferable. That is, it is preferable that R ¹ and R ² in the formula (2) are hydrogen atoms and R ³ is a hydrogen atom or a lower alkyl group having 4 or less carbon atoms (methyl group, ethyl group, etc.). Further, the linking group represented by Z ¹ preferably includes a heterocyclic structure, and k ¹ is preferably 1 or 2.

The specific polymer in the present invention preferably has an acid group in the side chain. The acid group may form a salt.
Examples of the acid group include a carboxyl group, a sulfo group, and a phosphoric acid group. Among these, a carboxyl group is preferable.
Further, the specific polymer in the present invention contains a carboxyl group-containing monomer as a copolymerization component in addition to a monomer having a phenyl group substituted by a vinyl group (more specifically, a group represented by the formula (2)). A copolymer is particularly preferred.
In this case, the proportion of the monomer having a phenyl group (preferably a group represented by formula (2)) substituted with a vinyl group in the copolymer composition is 1% by weight or more based on 100% by weight of the total composition. It is preferably 95% by weight or less, more preferably 10% by weight or more and 80% by weight or less, and further preferably 20% by weight or more and 70% by weight or less. When the content is in the above range, the effect of the specific polymer can be sufficiently exhibited, and the solubility during the one-liquid treatment can be sufficiently obtained.
Furthermore, the proportion of the carboxyl group-containing monomer in the copolymer is preferably 5% by weight or more and 99% by weight or less with respect to 100% by weight of the total composition. If it is in the above range, sufficient solubility during one-liquid treatment can be obtained.

Examples of the carboxyl group-containing monomer used as a copolymerization component include acrylic acid, methacrylic acid, acrylic acid-2-carboxyethyl ester, methacrylic acid-2-carboxyethyl ester, crotonic acid, maleic acid, fumaric acid, monoalkyl maleate Examples include esters, monoalkyl esters of fumaric acid, 4-carboxystyrene and the like.
Further, the specific polymer in the present invention contains a carboxyl group by using polyacetal containing benzoic acid in the side chain, carboxybenzaldehyde-modified polyvinyl alcohol, or the like as a copolymer component constituting the specific copolymer. Also good.

The polymer having a phenyl group substituted with a vinyl group in the side chain in the present invention may be a multi-component copolymer by introducing other monomer components into the copolymer in addition to the monomer having a carboxyl group. In such a case, examples of monomers that can be incorporated into the copolymer include:
Styrene derivatives such as styrene, 4-methylstyrene, 4-hydroxystyrene, 4-acetoxystyrene, 4-carboxystyrene, 4-aminostyrene, chloromethylstyrene, 4-methoxystyrene;
Alkyl methacrylates such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, cyclohexyl methacrylate, decyl methacrylate;
Methacrylic acid aryl esters or alkyl methacrylate aryl esters such as phenyl methacrylate and benzyl methacrylate;
Methacrylic acid esters having an alkyleneoxy group such as methacrylic acid-2-hydroxyethyl, methacrylic acid-2-hydroxypropyl, methacrylic acid methoxydiethylene glycol monoester, methacrylic acid methoxypolyethylene glycol monoester, methacrylic acid polypropylene glycol monoester;
Methacrylic acid esters containing amino groups such as 2-dimethylaminoethyl methacrylate and 2-diethylaminoethyl methacrylate;
Acrylic esters corresponding to these methacrylic esters;

Monomers having a phosphate group such as vinylphosphonic acid;
Monomers having an amino group such as allylamine and diallylamine;
Monomers having a sulfonic acid group such as vinyl sulfonic acid and its salt, allyl sulfonic acid and its salt, methallyl sulfonic acid and its salt, styrene sulfonic acid and its salt, 2-acrylamido-2-methylpropane sulfonic acid and its salt Kind;
Monomers having a nitrogen-containing heterocycle such as 4-vinylpyridine, 2-vinylpyridine, N-vinylimidazole, N-vinylcarbazole;
4-vinylbenzyltrimethylammonium chloride, acryloyloxyethyltrimethylammonium chloride, methacryloyloxyethyltrimethylammonium chloride, quaternized product of dimethylaminopropylacrylamide with methyl chloride, quaternized product of N-vinylimidazole with methyl chloride, 4-vinylbenzyl Monomers having a quaternary ammonium base such as pyridinium chloride;
Acrylamide or methacrylamide derivatives such as acrylamide, methacrylamide, dimethylacrylamide, diethylacrylamide, N-isopropylacrylamide, diacetoneacrylamide, N-methylolacrylamide, N-methoxyethylacrylamide, 4-hydroxyphenylacrylamide;
Vinyl esters such as acrylonitrile, methacrylonitrile, vinyl acetate, vinyl chloroacetate, vinyl propionate, vinyl butyrate, vinyl stearate, vinyl benzoate;
Vinyl ethers such as methyl vinyl ether and butyl vinyl ether;
In addition, various monomers such as phenylmaleimide, hydroxyphenylmaleimide, N-vinylpyrrolidone, acryloylmorpholine, tetrahydrofurfuryl methacrylate, vinyl chloride, vinylidene chloride, allyl alcohol, vinyltrimethoxysilane, glycidyl methacrylate can be used as appropriate. it can.

  As a ratio of these monomers in the copolymer, as long as a preferable ratio of the monomer having a group represented by the formula (2) and the carboxyl group-containing monomer in the copolymer composition described above is maintained. In any case, it can be introduced at an arbitrary ratio.

  The molecular weight of the polymer as described above is preferably in the range of 1,500 to 1,000,000, particularly preferably in the range of 10,000 to 300,000 in terms of weight average molecular weight.

  Examples (P-1) to (P-13) of polymers having a group represented by the formula (2) in the side chain are shown below. The number on the lower right of the parentheses in the structural formula represents the weight percent of each repeating unit in 100 weight percent of the total composition of the copolymer.

The (B) specific polymer as a binder polymer that can be used in the present invention may be used alone or in combination of two or more.
The content of the specific polymer (B) in the photosensitive layer is 10 to 90% by weight with respect to the total solid content of the photosensitive layer from the viewpoint of the strength (film properties and film strength) of the image area and image forming properties. It is preferably 20 to 80% by weight.
Moreover, the (B) specific polymer in this invention can also be used by mixing with other conventionally well-known binder polymers in the range which does not impair an effect.

[(C) Compound having two or more phenyl groups substituted with vinyl groups (polymerizable compound)]
In the present invention, the compound having two or more phenyl groups substituted with vinyl groups (hereinafter, also referred to as “specific monomer”) used as the polymerizable compound is produced by the radicals generated from the above-mentioned (A) radical generator. In order to effectively perform crosslinking by recombination of styryl radicals to be generated, the photosensitive layer containing these components can be preferably used for a photosensitive layer having high sensitivity and not requiring heat treatment.
The specific monomer preferably has a molecular weight of less than 1,500, and more preferably 1,200 or less.
The specific monomer in the present invention is preferably a compound represented by the following formula (3).

In formula (3), Z ² represents a linking group, and R ²¹ , R ²² and R ²³ each independently represent a hydrogen atom, a halogen atom, a carboxy group, a sulfo group, a nitro group, a cyano group, an amide group, or an amino group. An alkyl group, an aryl group, an alkoxy group, an aryloxy group, and the like, and these groups may be substituted with an alkyl group, an amino group, an aryl group, an alkenyl group, a carboxy group, a sulfo group, a hydroxy group, or the like. Good.
R ²⁴ represents a substitutable group or atom.
m ² represents an integer of 0 to 4, and k ² represents an integer of 2 or more.

The compound represented by formula (3) will be described in more detail.
As the linking group for Z ² , an oxygen atom, a sulfur atom, an alkylene group, an alkenylene group, an arylene group, —N (R ⁵ ) —, —C (O) —O—, —C (R ⁶ ) ═N—, Examples include —C (O) —, a sulfonyl group, a heterocyclic structure, a benzene ring structure, or a group in which two or more are combined. Here, R ⁵ and R ⁶ represent a hydrogen atom, an alkyl group, an aryl group, or the like. Furthermore, the linking group described above may have a substituent such as an alkyl group, an aryl group, or a halogen atom.

The heterocyclic structure constituting the linking group represented by Z ² includes pyrrole ring, pyrazole ring, imidazole ring, triazole ring, tetrazole ring, isoxazole ring, oxazole ring, oxadiazole ring, isothiazole ring, thiazole ring , Thiadiazole ring, thiatriazole ring, indole ring, indazole ring, benzimidazole ring, benzotriazole ring, benzoxazole ring, benzthiazole ring, benzselenazole ring, benzothiadiazole ring, pyridine ring, pyridazine ring, pyrimidine ring, pyrazine ring , Nitrogen-containing heterocycles such as triazine ring, quinoline ring and quinoxaline ring, furan ring and thiophene ring. These heterocyclic structures may further have a substituent such as an alkyl group, amino group, aryl group, alkenyl group, carboxy group, sulfo group or hydroxy group.

Examples of the substitutable group or atom represented by R ²⁴ include a halogen atom, a carboxy group, a sulfo group, a nitro group, a cyano group, an amide group, an amino group, an alkyl group, an aryl group, an alkoxy group, and an aryloxy group. Is mentioned. Furthermore, these groups or atoms may have a substituent such as an alkyl group, an amino group, an aryl group, an alkenyl group, a carboxy group, a sulfo group, or a hydroxy group.

Among the compounds represented by the formula (3), those having the structure shown below are preferable. That is, R ²¹ and R ²² in Formula (3) are hydrogen atoms, R ²³ is a hydrogen atom or a lower alkyl group having 4 or less carbon atoms (methyl group, ethyl group, etc.), and k ² is an integer of ² to 10. Certain compounds are preferred.
Specific examples (C-1) to (C-11) of the compound represented by the formula (3) are shown below, but are not limited to these specific examples.

The (C) specific monomer as a polymerizable compound that can be used in the present invention may be used alone or in combination of two or more.
The addition amount of the specific monomer (C) in the photosensitive layer is 0.01 to 10 parts by weight with respect to 1 part by weight of the polymer (binder polymer) having a phenyl group substituted with the vinyl group (B) in the side chain. It is preferable that it is contained in the range of 0.05-1 weight part.
Moreover, the (C) specific monomer in this invention can also be mixed with another conventionally well-known polymerizable compound in the range which does not impair an effect.

[(D) Infrared absorber]
The infrared absorbent that can be used in the present invention has a function of converting absorbed infrared light into heat and a function of generating excited electrons. When the infrared absorber absorbs light, it acts on the above-mentioned (A) radical generator, and (A) the radical generator is decomposed to generate radicals.
The infrared absorber used in the present invention is preferably a dye or pigment having an absorption maximum at a wavelength of 760 to 1,200 nm.

  As the dye, commercially available dyes and known dyes described in documents such as “Dye Handbook” (edited by the Society for Synthetic Organic Chemistry, published in 1970) can be used. Specifically, dyes such as azo dyes, metal complex azo dyes, pyrazolone azo dyes, naphthoquinone dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinoneimine dyes, methine dyes, cyanine dyes, squarylium dyes, pyrylium salts, metal thiolate complexes, etc. Is mentioned.

  As preferable dyes, for example, cyanine dyes described in JP-A Nos. 58-125246, 59-84356, 59-202929, and 60-78787, Methine dyes described in JP-A-58-173696, JP-A-58-181690, JP-A-58-194595, JP-A-58-112793, JP-A-58-224793 Naphthoquinone dyes described in JP-A-59-48187, JP-A-59-73996, JP-A-60-52940, JP-A-60-63744, etc., JP-A-58-112792 And squarylium dyes described in Japanese Laid-Open Patent Publication No. Gazette and the like, and cyanine dyes described in British Patent 434,875.

  In addition, a near infrared absorption sensitizer described in US Pat. No. 5,156,938 is also preferably used, and a substituted arylbenzo (thio) described in US Pat. No. 3,881,924 is also suitable. ) Pyrylium salt, trimethine thiapyrylium salt described in JP-A-57-142645 (US Pat. No. 4,327,169), JP-A-58-181051, 58-220143, 59- No. 41363, No. 59-84248, No. 59-84249, No. 59-146063, No. 59-146061, and Pyrlium compounds described in JP-A-59-216146. And pentamethine thiopyrylium salts described in US Pat. No. 4,283,475, and Japanese Patent Publication Nos. 5-13514 and 5-19702. Pyrylium compounds shown also preferably used. Another example of a preferable dye is a near-infrared absorbing dye described as a formula (I) or (II) in US Pat. No. 4,756,993.

Among these, the dye is preferably a cationic dye, and more preferably a cationic sensitizing dye.
Specific examples (S-1) to (S-14) of dyes as infrared absorbers are shown below, but are not limited thereto. In the following specific examples, Me represents a methyl group, Et represents an ethyl group, and Ph represents a phenyl group.

In addition, as described above, an infrared absorber in which the counter anion of the infrared absorber (cationic sensitizing dye) exemplified here is substituted with an organic boron anion can also be used.
These dyes may be used alone or in combination of two or more.
The content of the dye as an infrared absorber in the photosensitive layer is preferably 3 to 300 mg, more preferably 10 to ²⁰⁰ mg / m ² per 1 m ² of the photosensitive layer.

  Examples of pigments that can be used in the present invention include commercially available pigments and color index (CI) manual, “Latest Pigment Handbook” (edited by Japan Pigment Technical Association, published in 1977), “Latest Pigment Application Technology” (CMC Publishing). 1986), “Printing Ink Technology” CMC Publishing, 1984) can be used.

  Examples of the pigment include black pigments, yellow pigments, orange pigments, brown pigments, red pigments, purple pigments, blue pigments, green pigments, fluorescent pigments, metal powder pigments, and other polymer-bonded dyes. Specifically, insoluble azo pigments, azo lake pigments, condensed azo pigments, chelate azo pigments, phthalocyanine pigments, anthraquinone pigments, perylene and perinone pigments, thioindigo pigments, quinacridone pigments, dioxazine pigments, isoindolinone pigments In addition, quinophthalone pigments, dyed lake pigments, azine pigments, nitroso pigments, nitro pigments, natural pigments, fluorescent pigments, inorganic pigments, carbon black, and the like can be used.

These pigments may be used without surface treatment, or may be used after surface treatment.
The surface treatment method includes a method of surface coating with a resin or wax, a method of attaching a surfactant, a method of bonding a reactive substance (eg, silane coupling agent, epoxy compound, polyisocyanate, etc.) to the pigment surface, etc. Can be considered. The above-mentioned surface treatment methods are described in “Characteristics and Applications of Metal Soap” (Shobobo), “Printing Ink Technology” (CMC Publishing, 1984) and “Latest Pigment Application Technology” (CMC Publishing, 1986). Yes.

  The particle diameter of the pigment is preferably in the range of 0.01 μm to 10 μm, more preferably in the range of 0.05 μm to 1 μm, and still more preferably in the range of 0.1 μm to 1 μm. Within this preferred particle size range, excellent dispersion stability of the pigment in the photosensitive composition can be obtained, and when applied to a lithographic printing plate precursor, a uniform negative recording layer can be obtained.

  As a method for dispersing the pigment, a known dispersion technique used in ink production, toner production, or the like can be used. Examples of the disperser include an ultrasonic disperser, a sand mill, an attritor, a pearl mill, a super mill, a ball mill, an impeller, a disperser, a KD mill, a colloid mill, a dynatron, a three-roll mill, and a pressure kneader. Details are described in "Latest Pigment Applied Technology" (CMC Publishing, 1986).

  The content of the pigment as the infrared absorber in the photosensitive layer is 0 with respect to the total solid content in the photosensitive layer from the viewpoint of uniformity in the photosensitive layer and durability when applied to the photosensitive layer. It is preferably 0.01 to 50% by weight, more preferably 0.1 to 10% by weight, and further preferably 0.1 to 10% by weight.

  In addition to the above essential components (A) to (D), other components suitable for the application, production method and the like can be appropriately added to the photosensitive layer. Hereinafter, it illustrates about a preferable other component.

[Thermal polymerization inhibitor]
In the photosensitive layer, during production of the photosensitive layer or during storage of the lithographic printing plate precursor, a compound having a polymerizable ethylenically unsaturated double bond, that is, (C) a specific monomer (polymerizable compound) It is preferable to add a small amount of a thermal polymerization inhibitor in order to prevent unnecessary thermal polymerization.
Suitable thermal polymerization inhibitors include hydroquinone, p-methoxyphenol, di-t-butyl-p-cresol, pyrogallol, t-butylcatechol, benzoquinone, 4,4'-thiobis (3-methyl-6-t-butylphenol ), 2,2′-methylenebis (4-methyl-6-tert-butylphenol), N-nitrosophenylhydroxyamine primary cerium salt and the like.
The addition amount of the thermal polymerization inhibitor in the photosensitive layer is preferably 0.01 to 5% by weight with respect to the total solid content in the photosensitive layer.
Also, if necessary, higher fatty acid derivatives such as behenic acid and behenic acid amide may be added to prevent polymerization inhibition by oxygen, and unevenly distributed on the surface of the photosensitive layer during the drying process after coating. Good.
The addition amount of the higher fatty acid derivative in the photosensitive layer is preferably 0.5 to 10% by weight based on the weight of the total solid content in the photosensitive layer.

[Colorant]
Further, a dye or pigment may be added to the photosensitive layer for the purpose of coloring. Thereby, so-called plate inspection properties such as visibility after plate making and suitability for an image density measuring machine as a printing plate can be improved.
As the colorant, it is preferable to use a dye or a pigment. Specific examples include pigments such as phthalocyanine pigments, azo pigments, carbon black and titanium oxide, and dyes such as ethyl violet, crystal violet, azo dyes, anthraquinone dyes, and cyanine dyes.
The addition amount of the dyes and pigments as colorants in the photosensitive layer is preferably 0.5 to 5% by weight based on the total solid content in the photosensitive layer.
In the case of dyes, those containing no halogen ions as counter anions are preferred.

[Other additives]
Depending on the purpose, the photosensitive layer may further include an oxygen remover such as phosphine, phosphonate, phosphite, a reducing agent, an anti-fading agent, a surfactant, a plasticizer, an antioxidant, an ultraviolet absorber, an antifungal agent, You may use the antistatic agent and the additive which provides various other characteristics.

Moreover, you may add well-known additives, such as an inorganic filler for improving the physical property of a cured film, other plasticizers, and a fat-sensitizing agent which can improve the ink deposition property of the photosensitive layer surface.
Examples of the plasticizer include dioctyl phthalate, didodecyl phthalate, triethylene glycol dicaprylate, dimethyl glycol phthalate, tricresyl phosphate, dioctyl adipate, dibutyl sebacate, triacetyl glycerin and the like.
The plasticizer is preferably added in a range of 10% by weight or less with respect to the total weight of (B) the specific polymer (binder polymer) and (C) the specific monomer.
In addition, in order to enhance the effect of heating and exposure after development for the purpose of improving the film strength (printing durability) described later, an ultraviolet (UV) initiator, a thermal crosslinking agent, or the like can be added. .

  Furthermore, for the purpose of accelerating the polymerization, a polymerization accelerator represented by amine, thiol, disulfide and the like, a chain transfer agent and the like can be added. Specific examples thereof include N-phenylglycine, triethanolamine, N, N-diethylaniline and the like.

The photosensitive layer is provided by dissolving the components and the like in various organic solvents and coating them on a support or an intermediate layer (undercoat layer) described later.
Solvents used here include dioxane, acetone, methyl ethyl ketone, cyclohexane, ethyl acetate, ethylene dichloride, tetrahydrofuran, toluene, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol dimethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl. Ether, acetylacetone, cyclohexanone, diacetone alcohol, ethylene glycol monomethyl ether acetate, ethylene glycol ethyl ether acetate, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether acetate, 3-methoxypropanol, methoxymethoxyethanol, diethylene glycol monomethyl Ether, diethylene glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, 3-methoxypropyl acetate, N, N-dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, methyl lactate, Examples include ethyl lactate. These solvents can be used alone or in combination.
The concentration of the solid content in the coating solution is preferably 2 to 50% by weight.

The coating amount (thickness) of the photosensitive layer mainly affects the sensitivity of the photosensitive layer, the developability, and the strength and printing durability of the exposed film, and is preferably selected as appropriate according to the application.
From the viewpoint of printing durability, sensitivity, etc., the coating amount of the photosensitive layer is preferably 0.1 to 10 g / m ² in terms of weight after drying, and 0.5 to 5 g / m ^2. It is more preferable.

<Support>
As the support that can be used in the present invention, a support used in a conventionally known lithographic printing plate precursor, preferably a hydrophilic support, can be used without any particular limitation.
The support used is preferably a dimensionally stable plate, for example, paper, paper laminated with plastic (eg, polyethylene, polypropylene, polystyrene, etc.), metal plate (eg, aluminum, Zinc, copper, etc.), plastic film (for example, cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, etc.), above Examples thereof include paper or plastic film on which a metal such as the above is laminated or vapor-deposited.
These surfaces may be subjected to appropriate known physical and chemical treatments for the purpose of imparting hydrophilicity or improving strength, if necessary.

  Preferable supports include paper, polyester film or aluminum plate. Among them, dimensional stability is good, relatively inexpensive, and a surface having excellent hydrophilicity and strength can be provided by surface treatment as required. An aluminum plate is more preferable. A composite sheet in which an aluminum sheet is bonded on a polyethylene terephthalate film as described in Japanese Patent Publication No. 48-18327 is also preferable.

  An aluminum plate is a metal plate mainly composed of dimensionally stable aluminum. In addition to a pure aluminum plate, an alloy plate containing aluminum as a main component and containing a trace amount of foreign elements, or aluminum (alloy) is laminated. Or it is chosen from the vapor-deposited plastic film or paper. In the following description, the above-mentioned support made of aluminum or an aluminum alloy is generically used as an aluminum support. The foreign elements contained in the aluminum alloy include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel, titanium, etc., and the content of the foreign elements in the alloy is 10% by weight or less. In the present invention, a pure aluminum plate is suitable, but since completely pure aluminum is difficult to manufacture in the refining technique, it may contain a slightly different element. Thus, the composition of the aluminum plate applied to the present invention is not specified, and it is a conventionally known material such as JIS A 1050, JIS A 1100, JIS A 3103, JIS A 3005, etc. Can be used as appropriate.

In addition, the thickness of the aluminum support that can be used in the present invention can be appropriately changed according to the size of the printing press, the size of the printing plate, and the user's request. From the viewpoint of generation, 0.25 mm to 0.55 mm is preferable, and 0.3 to 0.50 mm is more preferable.
Furthermore, the aluminum support suitable for the present invention preferably has a surface shape as shown below.

[Surface shape of aluminum support]
In the aluminum support in the present invention, Ra, ΔS, and a45, which are surface shape factors, preferably satisfy the following conditions (i) to (iii), respectively.
(I) Ra: 0.2-0.40 μm
(Ii) ΔS: 35 to 85%
(Iii) a45: 25-55%
Here, Ra represents the surface roughness.
ΔS is obtained by the following equation from the actual area S _x obtained by the approximate three-point method and the geometric measurement area S ₀ .
ΔS (%) = (S _x −S ₀ ) / S ₀ × 100
a45 represents an area ratio of a portion having an inclination of 45 ° or more obtained by extracting a component having a wavelength of 0.2 μm or more and 2 μm or less.
Hereinafter, these surface shapes will be described in detail.

  (I) Ra represents the surface roughness. Here, the surface roughness (Ra) of the aluminum support means the centerline average roughness (arithmetic average roughness) in the direction perpendicular to the aluminum rolling direction. From the roughness curve measured with a stylus meter, When the portion of the measurement length L is extracted in the direction of the center line, the center line of the extracted portion is the X axis, and the axis perpendicular to the X axis is the Y axis, the roughness curve is expressed by Y = f (X). The value given by is expressed in μm. (The determination of L and the measurement of average roughness are in accordance with JIS B 0601.)

In general, it is effective to increase the surface roughness in order to improve the water retention. However, if the surface roughness is increased, deep recesses are likely to occur locally. Since a film tends to be formed, Ra needs to be in the range shown below.
That is, Ra is preferably in the range of 0.20 to 0.40 μm, more preferably in the range of 0.20 to 0.35 μm, and further preferably in the range of 0.25 to 0.35 μm. preferable.

As will be described in detail later, ΔS is an actual area S _x obtained by an approximate three-point method from three-dimensional data obtained by measuring 512 × 512 points of 50 × 50 μm of the support surface using an atomic force microscope. And the geometric measurement area (apparent area) S ₀ is obtained by the following equation.
ΔS (%) = (S _x −S ₀ ) / S ₀ × 100
The surface area ratio ΔS is a factor indicating the degree of increase in the actual area S _x by the roughening process with respect to the geometric measurement area S ₀ .

When ΔS increases, the contact area with the negative recording layer increases, and as a result, printing durability can be improved. Therefore, ΔS is preferably in the range shown below.
That is, ΔS is preferably in the range of 35 to 85%, more preferably in the range of 40 to 85%, and still more preferably in the range of 40 to 80%.

As described in detail later, a45 extracts components having a wavelength of 0.2 μm or more and 2 μm or less from three-dimensional data obtained by measuring 512 × 512 points of 50 × 50 μm of the support surface using an atomic force microscope. Represents the area ratio of the portion having the inclination of 45 ° or more.
The steepness is a factor representing the sharpness of the fine shape of the support surface. Specifically, it represents the ratio of the area having an inclination of a certain angle or more to the actual area in the unevenness of the support surface.

The area ratio (steepness) a45 of the slope having an inclination of 45 ° or more is preferably increased in order to improve the adhesion between the photosensitive layer and the support and to improve the printing durability. On the other hand, in order to suppress ink catching in the non-image area and improve stain resistance, it is preferable to make it smaller. For these reasons, a45 is preferably in the following range.
That is, a45 is preferably in the range of 25 to 55%, more preferably in the range of 30 to 55%, and still more preferably in the range of 30 to 50%.

  In the aluminum support in the present invention, ΔS and a45 are determined as follows.

(1) Measurement of surface shape by atomic force microscope In the present invention, in order to obtain ΔS and a45, first, the surface shape is measured by an atomic force microscope (AFM) to obtain three-dimensional data. .
The measurement can be performed, for example, under the following conditions. That is, the aluminum support is cut to a size of 1 cm square, set on a horizontal sample stage on a piezo scanner, the cantilever is approached to the sample surface, and when it reaches the region where the atomic force works, it scans in the XY direction. At that time, the unevenness of the sample is captured by the displacement of the piezo in the Z direction. A piezo scanner that can scan 150 μm in the XY direction and 10 μm in the Z direction is used. A cantilever having a resonance frequency of 120 to 150 kHz and a spring constant of 12 to 20 N / m (SI-DF20, manufactured by NANOPROBE) is used for measurement in a DFM mode (Dynamic Force Mode). Further, the reference plane is obtained by correcting the slight inclination of the sample by approximating the obtained three-dimensional data by least squares.
At the time of measurement, the surface of 50 × 50 μm is measured at 512 × 512 points. The resolution in the XY direction is 1.9 μm, the resolution in the Z direction is 1 nm, and the scan speed is 60 μm / sec.

(2) Correction of three-dimensional data For the calculation of ΔS, the three-dimensional data obtained in the above (1) is used as it is, but for the calculation of a45, the wavelength 0 is calculated from the three-dimensional data obtained in the above (1). Use a correction that removes components of 2 μm to 2 μm. With this correction, when a surface having deep irregularities, such as a support used in a lithographic printing plate precursor, is scanned with an AFM probe, the probe bounces against the edge of the convex portion, or the probe touches the wall surface of the deep concave portion. It is possible to remove noise that occurs when a part other than the tip of the contacted part.
The correction is performed by performing a fast Fourier transform on the three-dimensional data obtained in (1) above to obtain a frequency distribution, then removing components having a wavelength of 0.2 μm or more and 2 μm or less, and then performing an inverse Fourier transform. Do.

(3) Calculation of each factor and calculation of ΔS Using the three-dimensional data (f (x, y)) obtained in (1) above, three adjacent points are extracted, and a micro triangle formed by the three points Is obtained as a real area S _x . The surface area ratio ΔS is obtained from the obtained actual area S _x and the geometric measurement area S _{0 according} to the following formula. S ₀ is a geometric measurement area, which is determined by S ₀ = L _x × L _y , and in the present invention, L _x = L _y = 50 μm.
ΔS (%) = (S _x −S ₀ ) / S ₀ × 100

Calculation of a45 Using the three-dimensional data (f (x, y)) obtained by correcting in (2) above, three adjacent points are extracted, and a micro triangle formed by the three points and a reference plane Are calculated for all data to obtain a gradient distribution curve, and on the other hand, the sum of the areas of the small triangles is obtained as the actual area. From the gradient distribution curve, the area ratio a45 of the portion having a gradient of 45 degrees or more with respect to the actual area is calculated.

In this invention, the aluminum support body which has the surface shape mentioned above can be produced by performing the surface treatment mentioned later.
Hereinafter, the surface treatment applied to the aluminum support will be described.

(Roughening treatment)
Examples of the roughening treatment method include mechanical roughening, chemical etching, and electrolytic grain as disclosed in JP-A-56-28893. Further, an electrochemical surface roughening method in which the surface is electrochemically roughened in hydrochloric acid or nitric acid electrolyte solution, a wire brush grain method in which the aluminum surface is scratched with a metal wire, and the aluminum surface is sanded with a polishing ball and an abrasive. A mechanical roughening method such as a conspicuous pole grain method or a brush grain method of roughening the surface with a nylon brush and an abrasive can be used, and the above roughening methods are used alone or in combination. You can also
Among them, a method usefully used for roughening is an electrochemical method in which roughening is chemically carried out in hydrochloric acid or nitric acid electrolyte, and a suitable amount of electricity during anode is 50 C / dm ^{2 to} 400 C / dm ^2. Range. More specifically, in an electrolytic solution containing 0.1 to 50% hydrochloric acid or nitric acid, the temperature is 20 to 80 ° C., the time is 1 second to 30 minutes, and the current density is 10 A / dm ^{2 to} 50 A / dm ^2. It is preferable to perform direct current electrolysis.

The roughened aluminum support may be chemically etched with acid or alkali.
Examples of suitable etching agents include caustic soda, sodium carbonate, sodium aluminate, sodium metasilicate, sodium phosphate, potassium hydroxide, lithium hydroxide and the like, and preferred ranges of concentration and temperature are 1 to 50%, 20 to 100 ° C.
Pickling is performed to remove dirt (smut) remaining on the surface after etching. As the acid used, nitric acid, sulfuric acid, phosphoric acid, chromic acid, hydrofluoric acid, borohydrofluoric acid and the like are used.
In particular, as a method for removing smut after the electrochemical surface roughening treatment, contact with 15 to 65% by weight sulfuric acid at a temperature of 50 to 90 ° C. as described in JP-A-53-12739 is preferable. And the alkali etching method described in Japanese Patent Publication No. 48-28123.
After the treatment as described above, if Ra, ΔS, and a45, which are surface shape factors of the treated surface, satisfy the above conditions (i) to (iii), the method conditions are particularly limited to these. Not.

[Anodizing treatment]
The aluminum support that has been treated as described above to form an oxide layer is then anodized.
In the anodizing treatment, sulfuric acid, phosphoric acid, oxalic acid, or an aqueous solution of boric acid / sodium borate is used alone or in combination as a main component of an electrolytic bath. Under the present circumstances, the component normally contained in at least Al alloy plate, an electrode, tap water, groundwater, etc. may of course be contained in electrolyte solution. Further, the second and third components may be added. Here, the second and third components are, for example, metal ions such as Na, K, Mg, Li, Ca, Ti, Al, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn, and ammonium ions. Examples include cations, nitrate ions, carbonate ions, chloride ions, phosphate ions, fluorine ions, sulfite ions, titanate ions, silicate ions, borate ions, and the like, and the concentration is 0 to About 10,000 ppm may be contained.
Conditions for the anodic oxidation treatment, the anodized film weight made by the process is preferably 0.5~10.0g / m ^2, and more preferably 1.0 to 5.0 g / m ² .
In addition, the concentration of the acid as the main component of the electrolytic solution is usually 30 to 500 g / liter, the treatment solution temperature is 10 to 70 ° C., and the current density is 1 to 40 A / m ^{2 and} the treatment is performed by direct current or alternating current electrolysis. Is preferred.

[Hydrophilic treatment]
A widely known method can be applied as the hydrophilic treatment on the surface of the support. As a particularly preferable treatment, a hydrophilic treatment with silicate or polyvinylphosphonic acid is performed.
The formation amount of the film is preferably ² to 40 mg / m ² and more preferably 4 to 30 mg / m ² as the amount of Si or P element. The coating amount can be measured by fluorescent X-ray analysis.

  In the hydrophilization treatment, an alkali metal silicate or polyvinylphosphonic acid is 1 to 30 wt%, more preferably 2 to 15 wt%, and an aqueous solution having a pH of 10 to 13 at 25 ° C. It is preferable that the aluminum support on which the oxide film is formed is immersed, for example, at 15 to 80 ° C. for 0.5 to 120 seconds.

Examples of the alkali metal silicate that can be used for the hydrophilization treatment include sodium silicate, potassium silicate, and lithium silicate.
Examples of the hydroxide used for increasing the pH of the aqueous alkali metal silicate solution include sodium hydroxide, potassium hydroxide, and lithium hydroxide. In addition, you may mix | blend alkaline-earth metal salt or 14th group metal salt with said process liquid.
Alkaline earth metal salts include nitrates such as calcium nitrate, strontium nitrate, magnesium nitrate, and barium nitrate, and water-soluble substances such as sulfate, hydrochloride, phosphate, acetate, oxalate, and borate. Salt.
Group 14 metal salts include titanium tetrachloride, titanium trichloride, potassium titanium fluoride, potassium oxalate, titanium sulfate, titanium tetraiodide, zirconium chloride, zirconium dioxide, zirconium oxychloride, zirconium tetrachloride, etc. Can be mentioned.

Alkaline earth metal salts or Group 14 metal salts may be used alone or in combination of two or more.
The amount of these metal salts used is preferably 0.01 to 10% by weight, and more preferably 0.05 to 5.0% by weight. Silicate electrodeposition as described in US Pat. No. 3,658,662 is also effective.
Further, a support having electrolytic grains as disclosed in JP-B-46-27481, JP-A-52-58602, and JP-A-52-30503 is combined with the above-described anodizing treatment and hydrophilization treatment. Surface treatment is also useful.

<Back coat layer>
The lithographic printing plate precursor that can be used in the present invention may be provided with a backcoat layer on the back surface of the support, if necessary.
Such a back coat layer comprises a metal oxide obtained by hydrolysis and polycondensation of an organic polymer compound described in JP-A-5-45885 and an organic or inorganic metal compound described in JP-A-6-35174. A coating layer is preferably used.
Among these coating layers, silicon alkoxy compounds such as Si (OCH ₃ ) ₄ , Si (OC ₂ H ₅ ) ₄ , Si (OC ₃ H ₇ ) ₄ , and Si (OC ₄ H ₉ ) ₄ are available at a low price. The coating layer of the metal oxide provided therefrom is particularly preferred because of its excellent development resistance.

(Exposure process)
The plate making method of the lithographic printing plate of the present invention comprises: (A) a radical generator, (B) a polymer having a phenyl group substituted with a vinyl group in a side chain, and (C) a phenyl substituted with a vinyl group. An exposure step of image-exposing a lithographic printing plate precursor having a photosensitive layer containing a compound having two or more groups and (D) an infrared absorber is included.

As a light source for exposing the lithographic printing plate precursor that can be used in the present invention, an infrared laser is preferred, and thermal recording with an ultraviolet lamp or a thermal head is also possible.
In particular, in the present invention, it is preferable to perform image exposure with a solid-state laser and a semiconductor laser that emit infrared rays having a wavelength of 750 to 1,400 nm.
The laser output is preferably 100 mW or more, and a multi-beam laser device is preferably used in order to shorten the exposure time. The exposure time per pixel is preferably within 20 μsec.
The energy applied to the planographic printing plate precursor is preferably 10 to 300 mJ / cm ² . When it is in the above range, curing can proceed sufficiently, laser ablation can be suppressed, and damage to the image can be prevented.

The exposure in the present invention can be performed by overlapping the light beams of the light sources.
Overlap means that the sub-scanning pitch width is smaller than the beam diameter. The overlap can be expressed quantitatively by FWHM / sub-scanning pitch width (overlap coefficient), for example, when the beam diameter is expressed by the full width at half maximum (FWHM) of the beam intensity. In the present invention, the overlap coefficient is preferably 0.1 or more.

  The scanning method of the light source of the exposure apparatus that can be used in the present invention is not particularly limited, and a cylindrical outer surface scanning method, a cylindrical inner surface scanning method, a planar scanning method, and the like can be used. The channel of the light source may be a single channel or a multi-channel, but in the case of a cylindrical outer surface system, a multi-channel is preferably used.

(1 liquid treatment process)
Next, the one-component treatment process will be described in detail.
The plate-making method of the lithographic printing plate of the present invention includes a one-liquid processing step in which the photosensitive layer in the non-exposed area is removed and the plate surface is made hydrophilic with a processing liquid having a pH of 8.5 to 10.8. .
The “plate surface hydrophilization treatment” in the present invention means a surface treatment with a surfactant and / or a surface treatment with a water-soluble polymer compound. Also referred to as “gumming”.
In a normal processing step, if necessary, the protective layer is removed by a pre-water washing step, then alkali development is performed, the alkali is removed by a post-water washing step, gum treatment is performed in a gumming step, and drying is performed in a drying step. On the other hand, in the present invention, development can be performed with one liquid.
Preferably, gumming can be performed simultaneously with development by using an aqueous solution containing a buffer and a surfactant and / or a water-soluble polymer compound. Therefore, the post-water washing step is not particularly required, and development and gumming can be performed with one liquid. After development, it is preferable to dry after removing excess processing liquid using a squeeze roller or the like.

The one-liquid processing step in the present invention can be suitably carried out by an automatic processor equipped with a developer supply means and a rubbing member.
Examples of the automatic processor that can be used in the present invention include, for example, JP-A-2-220061 and JP-A-60-59351, which perform a rubbing process while transporting a lithographic printing plate precursor after image recording. US Pat. Nos. 5,148,746, 5,568,768, and British Patent 2,297,719, which rub the automatic printing machine described above and the lithographic printing plate precursor after image recording set on the cylinder while rotating the cylinder And an automatic processor described in the above. Among these, an automatic processor using a rotating brush roll as the rubbing member is particularly preferable.

A rotating brush roll that can be preferably used can be appropriately selected in consideration of the difficulty of scratching the image area and the strength of the support of the lithographic printing plate precursor. As the rotating brush roll, a known one formed by planting a brush material on a plastic or metal roll can be used. For example, as described in JP-A-58-159533, JP-A-3-100554, and Japanese Utility Model Publication No. 62-167253, a metal or plastic groove mold material in which brush materials are arranged in a row is used as a core. A brush roll can be used that is wound radially around a plastic or metal roll.
The brush material includes plastic fibers (for example, polyesters such as polyethylene terephthalate and polybutylene terephthalate, polyamides such as nylon 6.6 and nylon 6.10, polyacrylonitrile, poly (meth) acrylate, etc. Acrylic and polyolefin synthetic fibers such as polypropylene and polystyrene can be used. For example, the fiber has a hair diameter of 20 to 400 μm, and a hair length of 5 to 30 mm is preferable. Can be used.
Furthermore, the outer diameter of the rotating brush roll is preferably 30 to 200 mm, and the peripheral speed at the tip of the brush rubbing the plate surface is preferably 0.1 to 5 m / sec.
Moreover, it is preferable to use two or more rotating brush rolls if necessary.

  The rotating direction of the rotating brush roll may be the same or opposite to the conveying direction of the planographic printing plate precursor. However, when two or more rotating brush rolls are used, at least one rotating brush roll is used. It is preferred that the rotating brush rolls rotate in the same direction and at least one rotating brush roll rotates in the opposite direction. This further ensures the removal of the photosensitive layer in the non-image area. Furthermore, it is also effective to swing the rotating brush roll in the direction of the rotation axis of the brush roll.

  It is preferable to provide a drying step continuously or discontinuously after the one-component treatment step. Drying is performed by hot air, infrared rays, far infrared rays, or the like.

  FIG. 1 schematically shows an example of the structure of an automatic processor that is suitably used in the lithographic printing plate making method of the present invention. The automatic processor shown in FIG. 1 basically includes a developing unit 6 and a drying unit 10, and the planographic printing plate precursor 4 simultaneously removes the unexposed portion of the photosensitive layer and gums in the developing tank 20. A one-component treatment process is performed and dried in the drying unit 10.

In the present invention, the lithographic printing plate precursor after the rubbing treatment can optionally be subsequently washed with water, dried and desensitized.
In the desensitizing treatment, a known desensitizing solution can be used. Further, prior to the one-liquid treatment, it is possible to perform a water washing treatment in advance and remove the protective layer.

<Processing liquid>
The processing liquid used in the one-liquid processing step (hereinafter also referred to as “developer”) is preferably an aqueous solution containing a buffer and a surfactant and / or a water-soluble polymer compound.
The pH of the treatment liquid is 8.5 to 10.8, preferably 8.5 to 10.0, more preferably 8.5 to less than 10.0, and 9.0 to 9 More preferably, it is .8.

The developer that can be used in the present invention preferably contains a surfactant.
The surfactant may contain any of anionic, nonionic, cationic, and amphoteric.
Anionic surfactants include fatty acid salts, abietic acid salts, hydroxyalkane sulfonates, alkane sulfonates, dialkyl sulfosuccinates, linear alkyl benzene sulfonates, branched alkyl benzene sulfonates, alkyl naphthalene sulfonates. , Alkylphenoxy polyoxyethylene propyl sulfonates, polyoxyethylene alkyl sulfophenyl ether salts, N-methyl-N-oleyl taurine sodium, N-alkyl sulfosuccinic acid monoamide disodium salts, petroleum sulfonates, sulfated castor oil , Sulfated beef tallow oil, fatty acid alkyl ester sulfates, alkyl sulfates, polyoxyethylene alkyl ether sulfates, fatty acid monoglyceride sulfates Tell salt, polyoxyethylene alkylphenyl ether sulfate ester salt, polyoxyethylene styryl phenyl ether sulfate ester salt, alkyl phosphate ester salt, polyoxyethylene alkyl ether phosphate ester salt, polyoxyethylene alkylphenyl ether phosphate ester salt, styrene-anhydrous Partially saponified products of maleic acid copolymer, partially saponified products of olefin-maleic anhydride copolymer, naphthalene sulfonate formalin condensates, aromatic sulfonates, aromatic substituted polyoxyethylene sulfonates, etc. Is mentioned.
Among these, dialkyl sulfosuccinates, alkyl sulfate esters, and alkyl naphthalene sulfonates are particularly preferably used.

  The cationic surfactant is not particularly limited, and conventionally known cationic surfactants can be used. Examples thereof include alkylamine salts, quaternary ammonium salts, polyoxyethylene alkylamine salts, and polyethylene polyamine derivatives.

  Nonionic surfactants include polyethylene glycol type higher alcohol ethylene oxide adducts, alkylphenol ethylene oxide adducts, polyethylene glycol adducts of aromatic compounds, fatty acid ethylene oxide adducts, polyhydric alcohol fatty acid ester ethylene oxide adducts, Higher alkylamine ethylene oxide adduct, fatty acid amide ethylene oxide adduct, oil and fat ethylene oxide adduct, polypropylene glycol ethylene oxide adduct, dimethylsiloxane-ethylene oxide block copolymer, dimethylsiloxane- (propylene oxide-ethylene oxide) block copolymer, etc. And polyhydric alcohol glycerol fatty acid ester, pentaerythritol fatty acid ester, Rubitoru and fatty acid esters of sorbitan, fatty acid esters of sucrose, alkyl ethers of polyhydric alcohols, fatty acid amides of alkanolamines.

  In the present invention, a polyethylene glycol type higher alcohol ethylene oxide adduct, an aromatic compound polyethylene glycol adduct, sorbitol and / or sorbitan fatty acid ester ethylene oxide adduct, polypropylene glycol ethylene oxide adduct, dimethylsiloxane-ethylene oxide More preferred are block copolymers, dimethylsiloxane- (propylene oxide-ethylene oxide) block copolymers, and fatty acid esters of polyhydric alcohols.

Further, from the viewpoint of stable solubility or turbidity in water, the nonionic surfactant preferably has an HLB (Hydrophile-Lipophile Balance) value of 6 or more, more preferably 8 or more.
Also, acetylene glycol-based and acetylene alcohol-based oxyethylene adducts, fluorine-based and silicone-based surfactants can be used in the same manner.
Surfactants can be used alone or in combination.
The content of the surfactant in the developer is preferably from 0.01 to 10% by weight, and more preferably from 0.01 to 5% by weight.

As is well known in the field of surfactants, amphoteric surfactants are compounds having an anionic moiety and a cationic moiety in the same molecule, and are amphoteric such as amino acids, betaines, and amine oxides. A surfactant is included.
As the amphoteric surfactant that can be used in the developer, a compound represented by the following formula <1> and a compound represented by the following formula <2> are preferable.

In formula <1>, R ⁸ represents an alkyl group, R ⁹ and R ¹⁰ each independently represents a hydrogen atom or an alkyl group, R ¹¹ represents an alkylene group, and A represents a carboxylate ion or a sulfonate ion. Represent.
In formula <2>, R ¹⁸ , R ¹⁹ and R ²⁰ each independently represents a hydrogen atom or an alkyl group. However, not all of R ¹⁸ , R ¹⁹ and R ²⁰ are hydrogen atoms.

In the above formula <1>, the alkyl group in R ⁸ , R ⁹ or R ¹⁰ and the alkylene group in R ¹¹ may be linear or branched, and may have a linking group in the chain. In addition, it may further have a substituent. As the linking group, those containing a hetero atom such as an ester bond, an amide bond, or an ether bond are preferable. Moreover, as a substituent, a hydroxyl group, an ethylene oxide group, a phenyl group, an amide group, a halogen atom, etc. are preferable.
In the compound represented by the formula <1>, the total number of carbon atoms of R ^{8 to} R 11 is preferably ^{8 to} 25, and more preferably 11 to 21. Within the above range, the hydrophobic portion is appropriate and the solubility in an aqueous developer is excellent.
It is also possible to increase the solubility of the surfactant in an aqueous developer by adding an organic solvent, for example, a solubilizing agent such as alcohol.

In the above formula <2>, the alkyl group in R ¹⁸ , R ¹⁹ or R ²⁰ may be linear or branched, may have a linking group in the chain, and further has a substituent. You may do it. As the linking group, those containing a hetero atom such as an ester bond, an amide bond, or an ether bond are preferable. Moreover, as a substituent, a hydroxyl group, an ethylene oxide group, a phenyl group, an amide group, a halogen atom, etc. are preferable.
In the compound represented by the formula <2>, the total number of carbon atoms of R ^{18 to} R ²⁰ is preferably 8 to 22, and more preferably 10 to 20. Within the above range, the hydrophobic portion is appropriate and the solubility in an aqueous developer is excellent.

  The total carbon number of the amphoteric surfactant may be affected by the material used for the photosensitive layer, particularly the properties of the binder. In the case of a binder having a high degree of hydrophilicity, those having a relatively small total carbon number are preferred, and when the binder used has a low degree of hydrophilicity, those having a large total carbon number tend to be preferred.

  Preferable specific examples of the amphoteric surfactant that can be used in the developer are shown below, but the present invention is not limited thereto.

The developer that can be used in the present invention preferably contains a pH buffer (hereinafter also simply referred to as “buffer” or “pH buffer”).
Any pH buffering agent can be used without particular limitation as long as it is a buffering agent that exhibits a buffering action at pH 8.5 to 10.8.
In the present invention, an alkaline buffer is preferably used. For example, (a) carbonate ion and hydrogen carbonate ion, (b) borate ion, (c) water-soluble amine compound and ion of the amine compound, and The combined use etc. are mentioned. That is, for example, (a) a combination of carbonate ion-bicarbonate ion, (b) borate ion, or (c) a combination of water-soluble amine compound-ion of the amine compound, etc., has pH buffering action in the developer. Thus, even if the developer is used for a long period of time, it is possible to suppress fluctuations in pH, and it is possible to suppress development deterioration due to fluctuations in pH, generation of development residue, and the like. Particularly preferred is a combination of carbonate ions and bicarbonate ions.

(A) In order to allow carbonate ions and hydrogen carbonate ions to exist in the developer, carbonate and bicarbonate may be added to the developer, or the pH is adjusted after adding carbonate or bicarbonate. Thus, carbonate ions and hydrogen carbonate ions may be generated.
The carbonate and bicarbonate are not particularly limited, but are preferably alkali metal salts. Examples of the alkali metal include lithium, sodium, and potassium, and sodium is particularly preferable. These may be used alone or in combination of two or more.

(B) To make boric acid ions present in the developer, after adding boric acid and / or borate to the developer, the pH is adjusted using an alkali or using an alkali and an acid. Thus, an appropriate amount of borate ions is generated.
The boric acid and borate used here are not particularly limited, but known boric acid and borate can be used.
Examples of boric acid include orthoboric acid, metaboric acid, and tetraboric acid. Among them, orthoboric acid and tetraboric acid are preferable. Boric acid may be used alone or in combination of two or more.
Examples of the borate include alkali metal salts or alkaline earth metal salts, orthoborate, diborate, metaborate, tetraborate, pentaborate, octaborate. Among them, orthoborate, tetraborate, especially alkali metal tetraborate are preferable. Preferred tetraborate salts include sodium tetraborate, potassium tetraborate, and lithium tetraborate. Among them, sodium tetraborate is preferable. A borate may be used individually by 1 type, or may be used together 2 or more types.
As boric acid and / or borate that can be used in the present invention, orthoboric acid, tetraboric acid and / or sodium tetraborate are particularly preferable. Boric acid and borates may be used in combination with the developer.

(C) The water-soluble amine compound ions can be generated in an aqueous solution of the water-soluble amine compound, and an alkali or acid may be further added to the aqueous solution of the water-soluble amine compound. It can be made to contain in the aqueous solution by adding the compound which becomes.
The water-soluble amine compound is not particularly limited, but a water-soluble amine compound having a group that promotes water solubility is preferable. Examples of the group that promotes water solubility include a carboxylic acid group, a sulfonic acid group, a sulfinic acid group, a phosphonic acid group, and a hydroxyl group. The water-soluble amine compound may have a plurality of these groups.
When the water solubility of an amine compound is promoted by a carboxylic acid group, a sulfonic acid group, a sulfinic acid group, or a phosphonic acid group, it corresponds to an amino acid. The amino acid is in an equilibrium state in an aqueous solution, and when the acid group is, for example, a carboxylic acid group, the equilibrium state is expressed as follows. The amino acid in the present invention means the following B state, and the amino acid ion means the following C state. As the counter ion in the C state, sodium ion and potassium ion are preferable.
[Equilibrium state of amino acid (when acid group is carboxylic acid)]

（例えば、Ｒ¹及びＲ²はそれぞれ独立に、水素原子、アルキル基、アリール基などを表し、Ｒは連結基を表す。）

(For example, R ¹ and R ² each independently represents a hydrogen atom, an alkyl group, an aryl group, etc., and R represents a linking group.)

  Specific examples of water-soluble amine compounds having a carboxylic acid group, a sulfonic acid group, or a sulfinic acid group include glycine, iminodiacetic acid, lysine, threonine, serine, aspartic acid, parahydroxyphenylglycine, dihydroxyethylglycine, alanine, Examples thereof include amino acids such as anthranilic acid and tryptophan, fatty acid amine sulfonic acids such as sulfamic acid, cyclohexylsulfamic acid and taurine, and fatty acid amine sulfinic acids such as aminoethanesulfinic acid. Of these, glycine and iminodiacetic acid are preferred.

  Specific examples of the water-soluble amine compound having a phosphonic acid group (including a phosphinic acid group) include 2-aminoethylphosphonic acid, 1-aminoethane-1,1-diphosphonic acid, and 1-amino-1-phenylmethane-1. , 1-diphosphonic acid, 1-dimethylaminoethane-1,1-diphosphonic acid, ethylenediaminopentamethylenephosphonic acid, and the like. 2-aminoethylphosphonic acid is particularly preferable.

  A water-soluble amine compound having a hydroxyl group as a group that promotes water solubility means an alkylamine having a hydroxyl group on an alkyl group (state B ′ below), and these ions mean ammonium ions of an amino group ( State A ′) below.

（例えば、Ｒ¹、Ｒ²及びＲ³はそれぞれ独立に、水素原子、アルキル基、アリール基などを表す。ただし、Ｒ¹、Ｒ²及びＲ³のうちの少なくとも１つは水酸基を有するアルキル基である。）

(For example, R ¹ , R ² and R ³ each independently represents a hydrogen atom, an alkyl group, an aryl group, etc. provided that at least one of R ¹ , R ² and R ³ is an alkyl group having a hydroxyl group. .)

  Specific examples of the water-soluble amine compound having a hydroxyl group include monoethanolamine, diethanolamine, trimethanolamine, triethanolamine, tripropanolamine, and triisopropanolamine. Among these, triethanolamine and diethanolamine are preferable. As the counter ion of ammonium ion, chloride ion is preferable.

  Examples of the alkali that can be used for adjusting the pH include sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium carbonate, potassium carbonate, ammonium carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate, ammonium hydrogen carbonate, and organic alkali agents. , And combinations thereof can be used. As the acid, an inorganic acid such as hydrochloric acid, sulfuric acid, or nitric acid can be used. The pH can be finely adjusted by adding such an alkali or acid.

  The pH of the developer containing (a) carbonate ion and bicarbonate ion that can be used in the present invention is preferably in the range of pH 8.5 to 10.8. When the pH is 8.5 or more, the developability of the non-image area can be improved. On the other hand, when the pH is 10.8 or less, it is difficult to be influenced by carbon dioxide in the air, and the treatment is caused by the influence of carbon dioxide. A decrease in ability can be suppressed. More preferably, it is the range of pH8.8-10.2, Especially preferably, it is the range of pH9.0 or more and less than 10.0.

  When a combination of (a) carbonate ion and bicarbonate ion is employed as a pH buffer, the total amount of carbonate ion and bicarbonate ion is preferably 0.05 to 5 mol / L with respect to the total weight of the developer, 0.1-2 mol / L is more preferable, and 0.2-1 mol / L is particularly preferable. If the total amount is 0.05 mol / L or more, developability and processing capacity are not lowered, and if it is 5 mol / L or less, it becomes difficult to form precipitates and crystals, and further, during the waste liquid treatment of the developer, and during neutralization It becomes difficult to gel and does not interfere with waste liquid treatment.

Further, for the purpose of assisting the fine adjustment of the alkali concentration and the dissolution of the non-image area photosensitive layer, an alkali agent such as an organic alkali agent may be supplementarily used together.
Examples of the organic alkali agent include monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, triisopropylamine, n-butylamine, monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, Examples thereof include diisopropanolamine, ethyleneimine, ethylenediamine, pyridine, tetramethylammonium hydroxide and the like. These other alkaline agents are used alone or in combination of two or more.

  When (b) borate ions are employed as the pH buffering agent, the total amount of borate ions is preferably 0.05 to 5 mol / L, more preferably 0.1 to 2 mol / L, based on the total weight of the developer. 0.2 to 1 mol / L is particularly preferable. When the total amount of borate is 0.05 mol / L or more, developability and processing ability are not deteriorated. On the other hand, when it is 5 mol / L or less, it becomes difficult to form precipitates and crystals, and further, during the processing of waste liquid of the developer. It becomes difficult to gel during neutralization and does not interfere with waste liquid treatment.

  When (c) a water-soluble amine compound and ions of the amine compound are employed as the pH buffering agent, the total amount of the water-soluble amine compound and ions of the amine compound is 0.01 to the total weight of the developer. ˜1 mol / L is preferable, 0.03 to 0.7 mol / L is more preferable, and 0.05 to 0.5 mol / L is particularly preferable. When the pH is within the above range, developability and processing ability are not lowered, while waste liquid treatment is easy.

The developer that can be used in the present invention preferably contains a water-soluble polymer compound (hereinafter also referred to as “water-soluble resin”).
Examples of the water-soluble resin that can be contained in the developer that can be used in the present invention include soybean polysaccharide, modified starch, gum arabic, dextrin, fiber derivatives (for example, carboxymethylcellulose, carboxyethylcellulose, methylcellulose, and the like) and the like. Modified product, pullulan, polyvinyl alcohol and derivatives thereof, polyvinylpyrrolidone, polyacrylamide and acrylamide copolymer, vinyl methyl ether / maleic anhydride copolymer, vinyl acetate / maleic anhydride copolymer, styrene / maleic anhydride copolymer Examples include coalescence.
Moreover, the preferable acid value of water-soluble resin is 0-3.0 meq / g.

  As the soybean polysaccharide, conventionally known ones can be used. For example, as a commercial product, there is Soya Five (manufactured by Fuji Oil Co., Ltd.), and various grades can be used. What can be preferably used is one in which the viscosity of a 10% by weight aqueous solution is in the range of 10 to 100 mPa / sec.

  Examples of modified starch include those represented by the following formula (III). As the starch represented by the formula (III), any starch such as corn, potato, tapioca, rice and wheat can be used. These starch modifications can be made by, for example, a method of decomposing within 5 to 30 glucose residues per molecule with an acid or enzyme, and further adding oxypropylene in an alkali.

  In formula (III), etherification degree (substitution degree) is the range of 0.05-1.2 per glucose unit, n represents the integer of 3-30, m represents the integer of 1-3.

  Examples of modified starch and derivatives thereof include roasted starch such as British gum, enzyme modified dextrin such as enzyme dextrin and shardinger dextrin, oxidized starch shown in solubilized starch, modified pregelatinized starch and unmodified pregelatinized starch Alpha starch, phosphate starch, fat starch, sulfate starch, nitrate starch, xanthate starch, carbamic acid starch and other esterified starch, carboxyalkyl starch, hydroxyalkyl starch, sulfoalkyl starch, cyanoethyl starch, allyl starch, benzyl starch , Etherified starch such as carbamylethyl starch and dialkylamino starch, cross-linked starch such as methylol cross-linked starch, hydroxyalkyl cross-linked starch, phosphoric acid cross-linked starch and dicarboxylic acid cross-linked starch, starch polyacrylamide copolymer, starch polyacrylic acid co-polymer Polymer Starch polyvinyl acetate copolymer, starch polyacrylonitrile copolymer, chaotic starch polyacrylic acid ester copolymer, chaotic starch vinyl polymer copolymer, starch polystyrene maleic acid copolymer, starch polyethylene oxide copolymer, There are starch graft polymers such as starch polypropylene copolymer.

Among the water-soluble resins, preferred are soy polysaccharides, modified starches, gum arabic, dextrin, carboxymethyl cellulose, polyvinyl alcohol and the like.
Two or more water-soluble resins can be used in combination.
The content of the water-soluble resin in the treatment liquid is preferably 0.1 to 20% by weight, and more preferably 0.5 to 10% by weight.

The developer that can be used in the present invention preferably contains an organic acid, more preferably contains a hydroxycarboxylic acid, and further preferably contains a hydroxycarboxylic acid having two or more carboxyl groups.
The organic acid can also be used in the form of a salt such as an alkali metal salt or an ammonium salt thereof.
Further, the developer that can be used in the present invention preferably contains a hydroxycarboxylic acid ion (hydroxycarboxylate anion), and a hydroxycarboxylic acid ion (hydroxycarboxylate anion) having two or more carboxyl groups. It is particularly preferable to contain Within the above range, the fingerprint smudge prevention effect is excellent.
To ionize the hydroxycarboxylic acid in the developer, for example, a salt of hydroxycarboxylic acid can be used, or the pH of the developer can be made higher than the pKa value of the hydroxycarboxylic acid. Also, in the case of hydroxy carboxylic acid having two or more carboxyl groups, anions of in the developer ^- carboxyl groups and (-COO reduction) can be one, or may be two or more.
Examples of organic acids include citric acid, acetic acid, succinic acid, malonic acid, salicylic acid, caprylic acid, tartaric acid, malic acid, lactic acid, levulinic acid, p-toluenesulfonic acid, xylenesulfonic acid, phytic acid, and organic phosphonic acid. .
Among these, citric acid, salicylic acid, tartaric acid, malic acid, and lactic acid, which are hydroxycarboxylic acids, are preferred, and citric acid, tartaric acid, and malic acid, which are hydroxycarboxylic acids having two or more carboxyl groups. Is more preferable.

  In addition to the above, the developer that can be used in the present invention may contain a wetting agent, preservative, chelate compound, antifoaming agent, organic solvent, inorganic acid, inorganic salt, and the like.

As the wetting agent, ethylene glycol, propylene glycol, triethylene glycol, butylene glycol, hexylene glycol, diethylene glycol, dipropylene glycol, glycerin, trimethylolpropane, diglycerin and the like are preferably used. The wetting agent may be used alone or in combination of two or more.
The content of the wetting agent is preferably 0.1 to 5% by weight with respect to the total weight of the developer.

Preservatives include phenol or derivatives thereof, formalin, imidazole derivatives, sodium dehydroacetate, 4-isothiazolin-3-one derivatives, benzoisothiazolin-3-one, 2-methyl-4-isothiazolin-3-one, benztriazole derivatives Amiding anidine derivatives, quaternary ammonium salts, derivatives such as pyridine, quinoline, guanidine, diazine, triazole derivatives, oxazole, oxazine derivatives, nitrobromoalcohol-based 2-bromo-2-nitropropane-1,3-diol, 1,1-dibromo-1-nitro-2-ethanol, 1,1-dibromo-1-nitro-2-propanol and the like can be preferably used. It is preferable to use two or more kinds of preservatives in combination so as to be effective against various molds and sterilization.
The addition amount of the preservative is an amount that stably exerts an effect on bacteria, mold, yeast, etc., and varies depending on the type of bacteria, mold, yeast, but 0.01 to A range of 4% by weight is preferred.

Examples of the chelate compound include ethylenediaminetetraacetic acid, potassium salt thereof, sodium salt thereof; diethylenetriaminepentaacetic acid, potassium salt thereof, sodium salt thereof; triethylenetetraminehexaacetic acid, potassium salt thereof, sodium salt thereof, hydroxyethylethylenediaminetriacetic acid Nitrilotriacetic acid, sodium salt; 1-hydroxyethane-1,1-diphosphonic acid, potassium salt, sodium salt; aminotri (methylenephosphonic acid), potassium salt, sodium salt And organic phosphonic acids such as phosphonoalkanetricarboxylic acids. Organic amine salts are also effective in place of the sodium and potassium salts of the chelating agents.
As the chelating agent, one that is stably present in the composition of the treatment liquid and does not inhibit the printability is selected.
The addition amount of the chelating agent is preferably 0.001 to 1.0% by weight with respect to the developer.

As the antifoaming agent, a general silicone-based self-emulsifying type, emulsifying type, nonionic HLB 5 or less compound can be used. Among these, a silicone antifoaming agent is preferable.
Also, any antifoaming agent such as an emulsifying dispersion type and a solubilizing type can be used.
The content of the antifoaming agent is preferably in the range of 0.001 to 1.0% by weight with respect to the developer.

  Examples of the organic solvent include aliphatic hydrocarbons (hexane, heptane, “Isopar E, H, G” (produced by Esso Chemical Co., Ltd.), gasoline, kerosene, etc.), aromatic hydrocarbons (toluene, xylene, etc.) ), Halogenated hydrocarbons (methylene dichloride, ethylene dichloride, trichlene, monochlorobenzene, etc.) and polar solvents.

  Polar solvents include alcohols (methanol, ethanol, propanol, isopropanol, benzyl alcohol, ethylene glycol monomethyl ether, 2-ethoxyethanol, diethylene glycol monoethyl ether, diethylene glycol monohexyl ether, triethylene glycol monomethyl ether, propylene glycol monoethyl ether , Propylene glycol monomethyl ether, polyethylene glycol monomethyl ether, polypropylene glycol, tetraethylene glycol, ethylene glycol monobutyl ether, ethylene glycol monobenzyl ether, ethylene glycol monophenyl ether, methylphenyl carbinol, n-amyl alcohol, methyl amyl alcohol, etc.) , (Acetone, methyl ethyl ketone, ethyl butyl ketone, methyl isobutyl ketone, cyclohexanone, etc.), esters (ethyl acetate, propyl acetate, butyl acetate, amyl acetate, benzyl acetate, methyl lactate, butyl lactate, ethylene glycol monobutyl acetate, propylene Glycol monomethyl ether acetate, diethylene glycol acetate, diethyl phthalate, butyl levulinate, etc.) and others (triethyl phosphate, tricresyl phosphate, N-phenylethanolamine, N-phenyldiethanolamine, etc.).

  When the organic solvent is insoluble in water, it can be used after being solubilized in water using a surfactant or the like. When the developer contains an organic solvent, the concentration of the solvent is preferably less than 40% by weight from the viewpoints of safety and flammability.

Examples of inorganic acids and inorganic salts include phosphoric acid, metaphosphoric acid, primary ammonium phosphate, secondary ammonium phosphate, primary sodium phosphate, secondary sodium phosphate, primary potassium phosphate, secondary potassium phosphate, Examples include sodium tripolyphosphate, potassium pyrophosphate, sodium hexametaphosphate, magnesium nitrate, sodium nitrate, potassium nitrate, ammonium nitrate, sodium sulfate, potassium sulfate, ammonium sulfate, sodium sulfite, ammonium sulfite, sodium hydrogen sulfate, nickel sulfate and the like.
The content of the inorganic salt is preferably 0.01 to 0.5% by weight based on the total weight of the developer.

  The temperature at the time of removing the non-exposed portion of the photosensitive layer and gumming in the one-liquid processing step is preferably 60 ° C. or less, more preferably about 15 to 40 ° C. In the development processing using an automatic developing machine, the developing solution may be fatigued depending on the processing amount. Therefore, the processing capability may be restored using a replenishing solution or a fresh developing solution.

  After the one-liquid processing step is performed, the developer may be dried by natural drying, but it is preferable to provide a drying step using warm air or the like.

In the present invention, as described above, the one-liquid treatment process may be performed immediately after the exposure process, but a heat treatment process may be provided between the exposure process and the one-liquid treatment process. This heat treatment has the effect of improving the printing durability and further improving the uniformity of the image curing degree within the plate surface, and the conditions can be appropriately set within the range where these effects are present.
Examples of the heating means include a conventional convection oven, an IR irradiation device, an IR laser, a microwave device, a Wisconsin oven, and the like. For example, it can be preferably performed by holding the plate surface temperature in the range of 70 to 150 ° C. for 1 second to 5 minutes. More preferably, it is 80 degreeC-140 degreeC for 5 second-1 minute, More preferably, it is 90 degreeC-130 degreeC for 10 to 30 second. Within the above range, the above effects can be obtained efficiently, and there is no adverse effect such as deformation of the printing plate due to heat.
In the present invention, a lithographic printing plate is obtained by performing a one-liquid treatment step after the above-described exposure step and, if necessary, a heat treatment step. The plate setter used in the exposure process, the heat treatment means used in the heat treatment, and the developing device used in the one-liquid treatment process are preferably connected to each other and automatically processed continuously. Specifically, there is a plate making line in which a plate setter and a developing device are coupled by a conveying means such as a conveyor. A heat treatment unit may be provided between the plate setter and the developing device, and the heating unit and the developing device may be integrated.

When the lithographic printing plate precursor is easily affected by ambient light in the working environment, the plate making line is preferably shielded from light by a filter or a cover.
After image formation by development, the entire surface may be exposed with an actinic ray such as ultraviolet light to accelerate the curing of the image area.
Examples of the light source for the entire surface exposure include a carbon arc lamp, a mercury lamp, a gallium lamp, a metal halide lamp, a xenon lamp, a tungsten lamp, and various laser lights.
Further, as the amount of the entire surface exposure in order to obtain sufficient printing durability, it is preferably 10 mJ / cm ² or more, and more preferably 100 mJ / cm ² or more.
Heating may be performed simultaneously with the entire surface exposure, and further improvement in printing durability is recognized by heating.
Examples of the heating device include a conventional convection oven, an IR irradiation device, an IR laser, a microwave device, a Wisconsin oven, and the like.
At this time, the plate surface temperature is preferably 30 to 150 ° C, more preferably 35 to 130 ° C, and further preferably 40 to 120 ° C. Specifically, the method described in JP 2000-89478 A can be used.
The lithographic printing plate thus obtained is loaded on an offset printing machine and used for printing a large number of sheets.

  In the lithographic printing plate making method of the present invention, it is preferable to carry out whole surface post-heating or whole surface exposure on the image after the one-liquid treatment step for the purpose of improving the image strength and printing durability. Although extremely strong conditions can be used for heating after the one-liquid processing step, heating is performed from the viewpoint of obtaining a sufficient image strengthening action and suppressing heat damage in the support and the image portion. It is preferable that the temperature is in the range of 200 to 500 ° C.

The planographic printing plate obtained by the above processing is loaded on an offset printing machine and used for printing a large number of sheets.
Note that the stain on the planographic printing plate subjected to printing can be removed by a plate cleaner. As plate cleaners used for removing stains on the plate during printing, conventionally known plate cleaners for PS plates are used. For example, CL-1, CL-2, CP, CN-4, CN, CG-1, PC-1, SR, IC (made by FUJIFILM Corporation), etc. are mentioned.

EXAMPLES Hereinafter, although this invention is demonstrated according to the following examples, the scope of the present invention is not limited to these examples.
First, synthesis examples of typical compounds of (B) a polymer having a phenyl group substituted with a vinyl group in the side chain, and (C) a monomer having two or more phenyl groups substituted with a vinyl group are as follows. Show.

<Synthesis Example 1: Synthesis of (B) Specific Polymer (P-1)>
150 parts by weight of bismuthiol (2,5-dimercapto-1,3,4-thiadiazole) was suspended in 475 parts by weight of methanol, and 101 parts by weight of triethylamine was gradually added while cooling to obtain a uniform solution. . While maintaining at room temperature, 153 parts by weight of p-chloromethylstyrene (manufactured by Seimi Chemical Co., Ltd., CMS-14) was added dropwise over 10 minutes, and stirring was further continued for 3 hours. The reaction product gradually precipitated. After stirring, the reaction product was transferred to an ice bath, the internal temperature was cooled to 10 ° C., and the product was separated by suction filtration. The compound (monomer) shown below was obtained with a yield of 75% by washing with methanol and drying for one day in a vacuum dryer.

  Take 40 parts by weight of the monomer in a four-necked flask equipped with a stirrer, a nitrogen inlet tube, a thermometer, and a reflux condenser, add 70 parts by weight of methacrylic acid, 159 parts by weight of ethanol, and 50 parts by weight of distilled water. While stirring, 110 parts by weight of triethylamine was added on a water bath. The inside temperature was heated to 70 ° C. in a nitrogen atmosphere, and 1 part by weight of azobisisobutyronitrile (AIBN) was added at this temperature to initiate polymerization. The mixture was heated and stirred for 6 hours, and then the polymerization system was cooled to room temperature. A part was taken out, diluted hydrochloric acid was added to adjust the pH to about 3, and this was opened in water to obtain a polymer having the structure shown below.

  100 parts by weight of 1,4-dioxane and 23 parts by weight of p-chloromethylstyrene were added to the remaining polymer solution from which a part of the polymer was taken out, and stirring was further continued at room temperature for 15 hours. Thereafter, 80 to 90 parts by weight of concentrated hydrochloric acid (35 to 37% aqueous solution) was added, and after confirming that the pH of the system was 4 or less, the whole was transferred into distilled water. The precipitated polymer was separated by filtration, washed repeatedly with distilled water, and then dried for one day in a vacuum dryer. Thereby, the target (B) specific polymer (P-1) was obtained with a yield of 90%. It is a polymer with a weight average molecular weight of 90,000 (polystyrene conversion) by molecular weight measurement by gel permeation chromatography, and further supports the structure of (B) specific polymer (P-1) by analysis by proton NMR. there were.

<Synthesis Example 2: Synthesis Example of (C) Specific Monomer (C-5)>
A suspension of 89 parts by weight of thiocyanuric acid was suspended in 1,187 parts by weight of methanol, and a 30% aqueous solution in which 84 parts by weight of potassium hydroxide was dissolved was gradually added while cooling to obtain a uniform solution. To this, 230 parts by weight of p-chloromethylstyrene was gradually added dropwise at room temperature so that the internal temperature did not exceed 40 ° C. Shortly after the addition, the product was precipitated, but the stirring was continued, and after stirring for 3 hours, the product was separated by suction filtration. After washing with methanol and drying all day and night in a vacuum dryer, (C) the specific monomer (C-5) was obtained in a yield of 90%.

(Production of support)
The surface treatment shown below was performed using a JIS A 1050 aluminum plate having a thickness of 0.30 mm and a width of 1,030 mm.

<Surface treatment>
In the surface treatment, the following various treatments (a) to (f) were continuously performed. In addition, after each process and water washing, the liquid was drained with the nip roller.

(A) The aluminum plate was etched at a caustic soda concentration of 26 wt%, an aluminum ion concentration of 6.5 wt%, and a temperature of 70 ° C. to dissolve the aluminum plate by 5 g / m ² . Thereafter, it was washed with water.
(B) A desmut treatment by spraying was performed with a 1% by weight aqueous solution of nitric acid at a temperature of 30 ° C. (including 0.5% by weight of aluminum ions), and then washed with water.

(C) An electrochemical surface roughening treatment was continuously performed using an alternating voltage of 60 Hz. The electrolytic solution at this time was a 1 wt% nitric acid aqueous solution (containing 0.5 wt% aluminum ions and 0.007 wt% ammonium ions), and the temperature was 30 ° C. The AC power source was subjected to an electrochemical surface roughening treatment using a carbon electrode as a counter electrode using a trapezoidal rectangular wave alternating current with a time TP of 2 msec until the current value reached a peak from zero and a duty ratio of 1: 1. Ferrite was used for the auxiliary anode. The current density was 25 A / dm ² at the peak current value, and the amount of electricity was 250 C / cm ² in terms of the total amount of electricity when the aluminum plate was the anode. 5% of the current flowing from the power source was shunted to the auxiliary anode. Thereafter, it was washed with water.

(D) The aluminum plate was spray-etched at 35 ° C. with a caustic soda concentration of 26% by weight and an aluminum ion concentration of 6.5% by weight, and the aluminum plate was dissolved at 0.2 g / m ² , and electricity was used using the alternating current of the previous stage. The removal of the smut component mainly composed of aluminum hydroxide generated during chemical roughening and the edge portion of the generated pit were dissolved to smooth the edge portion. Thereafter, it was washed with water.
(E) A desmut treatment by spraying was performed with a 25% by weight aqueous solution of sulfuric acid having a temperature of 60 ° C. (containing 0.5% by weight of aluminum ions), followed by washing with water by spraying.

(F) Anodizing was performed for 50 seconds at a sulfuric acid concentration of 170 g / liter (containing 0.5 wt% of aluminum ions), a temperature of 33 ° C., and a current density of 5 (A / dm ² ). Thereafter, it was washed with water. At this time, the weight of the anodized film was 2.7 g / m ² .

  The surface roughness Ra, surface area ratio ΔS, and steepness a45 of the aluminum support thus obtained were Ra = 0.27 (measuring instrument: Surfcom manufactured by Tokyo Seimitsu Co., Ltd., stylus tip diameter 2 microns), respectively. Meter), ΔS = 75%, a45 = 44% (measuring instrument; SPA300 / SPI3800N manufactured by Seiko Instruments Inc.).

(Formation of undercoat layer)
Next, the following undercoat layer coating solution was applied to the surface of the aluminum support with a wire bar and dried at 100 ° C. for 10 seconds. The coating amount was 5 mg / m ² .
-Undercoat layer coating solution-
・ Polyvinylphosphonic acid 0.024 weight part ・ Methanol 27 weight part ・ Ion-exchanged water 3 weight part

[Formation of photosensitive layer]
Next, the following photosensitive layer coating solution is prepared, applied to the aluminum support subjected to the above surface treatment so that the thickness after drying becomes 1.4 μm, and dried in a dryer at 70 ° C. for 5 minutes. The lithographic printing plate precursor (CTP-1) was obtained.

<Photosensitive layer coating solution>
-(A) radical generator (BC-6) 2.0 parts by weight-(A) radical generator (T-4) 2.0 parts by weight-(B) specific polymer (P-1) 10.0 parts by weight Part (C) Specific monomer (C-5) 3.5 part by weight (D) Infrared absorber (S-4) 0.5 part by weight Chloride salt of ethyl bio red 0.3 part by weight Dioxane 70. 0 parts by weight, cyclohexane 20.0 parts by weight

  The components (A) to (D) used in the recording layer coating liquid are those described as the specific examples described above.

(Examples 1-22 and Comparative Examples 1-3)
[Exposure, 1 component treatment and printing]
Each of the above lithographic printing plate precursors was subjected to a Trendsetter 3244VX manufactured by Creo equipped with a water-cooled 40 W infrared semiconductor laser, with a resolution of 175 lpi, an output of 8 W, a dot area ratio of 50%, an outer drum rotation speed of 206 rpm, and a plate surface energy of 100 mJ / cm ² . Exposed.
Next, each processing solution having the composition described in Tables 1 to 3 below was used, and one-solution processing was performed with an automatic developing processor having a structure as shown in FIG. The automatic development processor has a 25 L developing tank, and has one brush roll having an outer diameter of 50 mm in which fibers made of polybutylene terephthalate (hair diameter 200 μm, hair length 17 mm) are implanted. 200 revolutions per minute in the same direction (peripheral speed of brush tip 0.52 m / sec). The temperature of the treatment liquid was 28 ° C. The planographic printing plate precursor was transported at a transport speed of 100 cm / min. After the development processing, drying was performed in a drying section. The drying temperature was 80 ° C.

[Evaluation]
<Print durability>
Every time 10,000 sheets of the obtained lithographic printing plate are printed using a printing machine Lithron manufactured by Komori Corporation, the work of wiping off the ink from the surface of the printing plate with a multi-cleaner manufactured by Fuji Film Co., Ltd. is repeated. Printing was performed while the number of completed sheets was used as an index of printing durability. As the number of printed sheets is increased, the image on the photosensitive layer formed on the planographic printing plate gradually wears and the ink acceptability is lowered, and accordingly, the ink density of the image in the printed material is lowered. Therefore, the printing durability (immediately after production) was evaluated by the number of printed sheets when the ink density (reflection density) was reduced by 0.1 from the start of printing.
Further, after preparing a lithographic printing plate, the plate was left for 1 week in an environment of temperature 25 ° C. and humidity 60%, then printed under the above conditions, and the printing durability (after 1 week) was similarly evaluated.

<Processability>
When each lithographic printing plate precursor was developed for 500 m ² under the above conditions for one week, the state of occurrence of debris adhering to the wall of the automatic processor was visually observed. During the processing, the developer was not replenished but only the evaporated water was replenished. When no residue was generated: ◯, when residue was generated but at an acceptable level: Δ, and when residue was significant: x.

<Fingerprint marks>
The non-image area of the printing plate developed by the above method is pressed with a thumb for 10 seconds, and the printing plate developed in an environment of room temperature 25 ° C. and humidity 70% is protected with a slip sheet 1 Left for days. The plate was printed, and it was evaluated whether or not the pressed area was stained. The evaluation criteria are shown below.
○: Print stains do not occur.
Δ: Slight pot-like print stains are recognized, but are within an allowable range.
X: Print marks on finger marks become dirty.

  Tables 1 to 4 below show the compositions of the treatment liquids used in Examples 1 to 22 and Comparative Examples 1 to 3, and Table 5 shows the evaluation results of Examples 1 to 22 and Comparative Examples 1 to 3. .

In addition, the commercial item used in the table | surface is as showing below.
New Coal B13: Polyoxyethylene β-naphthyl ether (oxyethylene average number n = 13, manufactured by Nippon Emulsifier Co., Ltd.)
New Coal B4SN (61% aqueous solution): Polyoxyethylene aryl ether sulfate (manufactured by Nippon Emulsifier Co., Ltd.)
Eleminol MON (47% aqueous solution): Sodium dodecyl diphenyl ether disulfonate (manufactured by Sanyo Chemical Industries)
pioninD3110: Higher alkylamine ethylene oxide adduct (manufactured by Takemoto Yushi Co., Ltd.)
Perex NBL (35% aqueous solution): Alkylnaphthalenesulfonate (manufactured by Kao Corporation)
pionin C157K: alkyldimethylaminoacetic acid betaine (manufactured by Takemoto Yushi Co., Ltd.)
Takesurf C-157-L: alkyldimethylaminoacetic acid betaine (manufactured by Takemoto Yushi Co., Ltd.)
EDTA 4Na is an abbreviation for ethylenediaminetetraacetic acid tetrasodium salt.
Further, Benon JE66 manufactured by Nippon Star Chemical Co., Ltd. was used as the hydroxyalkylated starch.

  From the results of Table 5, it can be seen that according to the plate making method of the lithographic printing plate of the present invention, there is almost no decrease in printing durability due to the plate after development, and no residue is formed in the developing tank. Furthermore, fingerprints do not stain even when handled with bare hands.

It is explanatory drawing which shows the structure of an automatic developing processor.

Explanation of symbols

4 Planographic printing plate precursor 6 Developing unit 10 Drying unit 16 Transport roller 20 Developing tank 22 Transport roller 24 Brush roller 26 Squeeze roller 28 Backup roller 36 Guide roller 38 Skewer roller

Claims (8)

On the support (A) a radical generator, (B) a polymer having a phenyl group substituted with a vinyl group in the side chain, (C) a compound having two or more phenyl groups substituted with a vinyl group, and ( D) an exposure process for image exposure of a lithographic printing plate precursor having a photosensitive layer containing an infrared absorber, and
pH is seen containing a liquid treatment step carried out in one liquid removal and plate surface hydrophilic treatment of the photosensitive layer of the non-exposed portion by the processing liquid is 8.5 to 10.8,
The treatment liquid is an aqueous solution containing a buffer and a surfactant and / or a water-soluble polymer compound,
The method of making a lithographic printing plate , wherein the buffer contains a carbonate . The lithographic printing plate making method according to claim 1, wherein the pH of the treatment liquid is 8.5 or more and less than 10.0. Said processing liquid, process for making a lithographic printing plate according to claim 1 or 2 containing an ion of a hydroxycarboxylic acid. The lithographic printing plate making method according to claim 3 , wherein the hydroxycarboxylic acid is a hydroxycarboxylic acid having two or more carboxyl groups. The lithographic printing plate making method according to claim 3 or 4 , wherein the hydroxycarboxylic acid ion is at least one ion selected from the group consisting of citrate ion, tartrate ion and malate ion. The plate-making method of a lithographic printing plate according to any one of claims 1 to 5 , wherein the polymer (B) having a phenyl group substituted with a vinyl group in a side chain further has an acid group in a side chain. The lithographic printing plate making method according to claim 6 , wherein the acid group is a carboxyl group. On the support (A) a radical generator, (B) a polymer having a phenyl group substituted with a vinyl group in the side chain, (C) a compound having two or more phenyl groups substituted with a vinyl group, and ( D) an exposure process for image exposure of a lithographic printing plate precursor having a photosensitive layer containing an infrared absorber, and
including a one-liquid processing step in which the removal of the photosensitive layer in the non-exposed area and the hydrophilization treatment of the plate surface are performed with one liquid using a processing liquid having a pH of 8.5 to 10.8,
Characterized in that neither subjected to water washing step either before or after the first liquid treatment step
Plate making method of lithographic printing plate.

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