JP5244523B2 - Preparation method of lithographic printing plate - Google Patents

Description

  The present invention relates to a method for preparing a lithographic printing plate, and particularly relates to a method for preparing a lithographic printing plate that has a high processing capability and can be processed with one liquid.

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 utilizes 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 and the hydrophilic non-image area is dampened with the water receiving area (ink non-receiving area). As described above, a difference in ink adhesion is caused on the surface of a lithographic printing plate, and after ink is applied only to an image portion, 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 recording 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 image portion of the image recording layer is left, and the other unnecessary image recording layer is removed 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 the conventional lithographic printing plate precursor, a step of dissolving and removing an unnecessary image recording layer with a developer or the like is necessary after exposure, but it is closer to the 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. Accordingly, 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. However, as described above, the conventional development processing step consists of three steps of developing with an alkaline aqueous solution having a pH of 11 or more, then pouring an alkaline agent in a washing bath, and then processing with a gum solution mainly containing 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.

On the other hand, for example, Patent Document 1 proposes a developing method in which processing is performed with a developer having an alkali metal carbonate and a bicarbonate having a pH of 8.5 to 11.5 and an electrical conductivity of 3 to 30 mS / cm. However, it requires water washing and a gum solution treatment process, and does not lead to solution of environmental and running cost problems.
Moreover, the Example of patent document 2 describes the process by the process liquid containing the water-soluble high molecular compound of pH 11.9-12. However, the printing plate obtained by this treatment is in a state in which the alkali of pH 12 remains attached to the plate surface, and there is a problem in terms of safety for the operator, and the time until printing after the printing plate preparation is long. As a result, the image portion gradually dissolves, resulting in a decrease in printing durability and inking properties.
Patent Document 3 describes treatment with a treatment liquid containing a water-soluble polymer compound having a pH of 3 to 9. However, since this processing solution does not contain a base component, it is necessary to make the polymer of the photosensitive layer hydrophilic so that it can be developed, and there is a problem that printing durability is remarkably lowered.
Patent Document 4 proposes an image recording material which contains a sulfonamide group-containing polymer compound as a binder and forms an image by heat mode exposure. However, even if this image recording material is used, since a post-processing step using a rinsing liquid and a desensitizing liquid is required, the problem of environmental and running costs cannot be solved as in Patent Document 1.
JP-A-11-65126 European Patent Application No. 1868036 Special table 2007-538279 gazette JP 2001-242612 A

  Accordingly, an object of the present invention is to provide a method for preparing a lithographic printing plate that overcomes the above-mentioned drawbacks of the prior art. Specifically, in a low pH region (for example, pH 11 or less), developability, processability, Producing a lithographic printing plate capable of one-liquid processing that achieves both anti-staining properties and sufficient printing durability, and does not deteriorate printing durability even when the printing plate is stored before printing after development. It is to provide a method.

As a result of intensive studies, the present inventor has found that the object can be achieved by the following configuration, and has completed the present invention.
That is, the present invention is as follows.
[1]
A negative lithographic printing plate precursor having an image recording layer containing the following (i), (ii), (iii) and (iv) on a hydrophilic support is subjected to image exposure, and then carbonate ions and bicarbonate ions A method for preparing a lithographic printing plate, wherein the aqueous solution has a pH of 8.5 to 10.8.
(I) Sensitizing dye
(Ii) Photopolymerization initiator
(Iii) Addition-polymerizable compound having an ethylenically unsaturated double bond
(Iv) Binder polymer having a structure represented by the general formula (I) in the side chain
—L ₁ —X—NH—Y—R ₁ (I)
(In the formula, L ₁ represents a single bond or a divalent linking group bonded to the polymer main chain. X and Y each independently represent a single bond or a divalent linking group, provided that X, Y At least one of — represents —SO ₂ —, and R ₁ represents a hydrogen atom or a monovalent organic group.)
[2]
In the general formula (I), each of X and Y is —CO— or —SO ₂ —. The method of preparing a lithographic printing plate as described in [1] above,
[3]
The method for preparing a lithographic printing plate as described in [1] or [2] above, wherein (i) the sensitizing dye has an absorption maximum in a wavelength region of 350 nm to 450 nm.
[4]
The method for preparing a lithographic printing plate as described in any one of [1] to [3] above, wherein the image exposure is performed using a laser emitting light of 350 nm to 450 nm.
[5]
The method of preparing a lithographic printing plate as described in any one of [1] to [4] above, wherein the lithographic printing plate precursor further comprises a protective layer on the image recording layer.
[6]
The method for preparing a lithographic printing plate as described in [5] above, wherein the protective layer contains acid-modified polyvinyl alcohol.
[7]
The method for preparing a lithographic printing plate as described in any one of [1] to [6] above, wherein the aqueous solution further contains a water-soluble polymer compound.
[8]
The method of preparing a lithographic printing plate as described in any one of [1] to [7] above, wherein the treatment with the aqueous solution is performed with one liquid.
The present invention has the above-described configurations [1] to [8], and the other is described below for reference.

(1) A negative lithographic printing plate precursor having an image recording layer containing the following (i), (ii), (iii) and (iv) on a hydrophilic support, image-exposed, and carbonate ions A method for preparing a lithographic printing plate, comprising treating with an aqueous solution containing hydrogen carbonate ions.
(I) Sensitizing dye (ii) Photopolymerization initiator (iii) Addition polymerizable compound having an ethylenically unsaturated double bond (iv) Binder polymer-L having a structure represented by formula (I) in the side chain ₁ —X—NH—Y—R ₁ (I)
(In the formula, L ₁ represents a single bond or a divalent linking group bonded to the polymer main chain. X and Y each independently represent a single bond or a divalent linking group, provided that X, Y At least one of, -SO ₂ - .R1 representing a represents a hydrogen atom or a monovalent organic group).
(2) The method for preparing a lithographic printing plate as described in (1) above, wherein in the general formula (I), each of X and Y is —CO— or —SO ₂ —.
(3) The method for preparing a lithographic printing plate as described in (1) or (2) above, wherein the (i) sensitizing dye has an absorption maximum in a wavelength region of 350 nm to 450 nm.
(4) The method of preparing a lithographic printing plate as described in any one of (1) to (3) above, wherein the image exposure is performed using a laser emitting light of 350 nm to 450 nm.
(5) The method of preparing a lithographic printing plate as described in any one of (1) to (4) above, wherein the pH of the aqueous solution is 8.5 to 10.8.
(6) The method for producing a lithographic printing plate as described in any one of (1) to (5) above, wherein the lithographic printing plate precursor further comprises a protective layer on the image recording layer.
(7) The method for producing a lithographic printing plate as described in (6) above, wherein the protective layer contains acid-modified polyvinyl alcohol.
(8) The method for preparing a lithographic printing plate as described in any one of (1) to (7) above, wherein the aqueous solution further contains a water-soluble polymer compound.
(9) The method for producing a lithographic printing plate as described in any one of (1) to (8) above, wherein the treatment with the aqueous solution is performed with one liquid.

According to the present invention, in the low pH region (for example, pH 11 or less), the printing plate is stored before printing after development, while at the same time having sufficient characteristics regarding developability, processability, antifouling property, and printing durability. Even in this case, it is possible to provide a method for preparing a lithographic printing plate capable of one-liquid processing without causing deterioration in printing durability.
More specifically, according to the present invention, there is no halftone flat screen unevenness due to high-definition AM screen printing or FM screen printing having a screen line number of 200 lines or more, particularly exposure using an FM screen, by laser light. A printing plate giving good prints is provided. Further, even when the printing plate is stored before development and before printing, the printing durability does not deteriorate. Furthermore, since one-component development is possible with a weak alkaline processing solution, advantages such as simplification of processing steps, consideration for the global environment, space saving, and adaptation to low running costs can be provided.

[Negative lithographic printing plate precursor]
The structure of the negative planographic printing plate precursor in the present invention will be described in order.

[Support]
First, the hydrophilic support of the lithographic printing plate precursor used in the present invention will be described.
Any material can be used as the support as long as the surface is hydrophilic, but a dimensionally stable plate-like material is preferable. For example, paper on which paper, plastic (for example, polyethylene, polypropylene, polystyrene, etc.) is laminated. And a plate of a metal such as aluminum (including an aluminum alloy), zinc, copper or the like or an alloy thereof (eg, an alloy with silicon, copper, manganese, magnesium, chromium, zinc, lead, bismuth, nickel), Further, for example, a plastic film such as cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose butyrate acetate, cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, etc. Also Alloys having laminated or vapor-deposited paper or plastic films. Of these supports, the aluminum plate is particularly preferred because it is dimensionally remarkably stable and inexpensive. Further, 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. Usually, the thickness is about 0.05 mm to 1 mm.

Further, in the case of a support having a surface of metal, particularly aluminum, surface treatment such as graining treatment described later, immersion treatment in an aqueous solution of sodium silicate, potassium fluoride zirconate, phosphate or the like, or bipolar oxidation treatment, etc. It is preferable that
[Graining process]
The graining method consists of an electrochemical graining method in which graining is carried out electrochemically in hydrochloric acid or nitric acid electrolyte, and a wire brush grain method in which the aluminum surface is scratched with a metal wire. A mechanical graining method such as a sharpening ball grain method or a brush graining method in which the surface is grained with a nylon brush and an abrasive can be used, and the above graining methods can be used alone or in combination. For example, Japanese Patent Laid-Open No. 56-28893 describes a method of performing mechanical graining, chemical etching, and electrolytic graining.
Specifically, a method of making a useful surface roughness is an electrochemical method of chemically graining in a hydrochloric acid or nitric acid electrolytic solution, suitable current density of 100C / dm ² ~400C / dm ² ranges It is. More specifically, in the electrolytic solution containing from 0.1 to 50% hydrochloric acid or nitric acid, the temperature 20 to 100 ° C., for 1 second to 30 minutes, electrolysis at a current density of 100C / dm ² ~400C / dm ² It is preferable to carry out.

The grained aluminum support is chemically etched with acid or alkali. When an acid is used as an etchant, it takes time to destroy the microstructure. This problem can be improved by using alkali as an etching agent.
Examples of the alkali agent suitably used 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%, The conditions are such that the temperature is 20 to 100 ° C. and the aluminum dissolution amount is 5 to 20 g / m ³ .
After etching, pickling is performed to remove dirt (smut) remaining on the surface. Examples of the acid used include nitric acid, sulfuric acid, phosphoric acid, chromic acid, hydrofluoric acid, and borohydrofluoric acid. In particular, as a method for removing smut after electrochemical surface roughening treatment, a method of contacting with 15 to 65% by mass of sulfuric acid at a temperature of 50 to 90 ° C. as described in JP-A No. 53-12739, Further, the alkali etching method described in JP-B-48-28123 is preferred.
The preferable aluminum substrate has a surface roughness (Ra) of 0.3 to 0.7 μm.

[Anodic oxidation treatment]
The aluminum support that has been grained as described above may be further anodized. The anodizing treatment can be performed by a method conventionally performed in this technical field.
Specifically, sulfuric acid, phosphoric acid, chromic acid, oxalic acid, sulfamic acid, benzene sulfonic acid, etc., or a combination of two or more of these, and when direct current or alternating current is applied to aluminum in an aqueous solution or non-aqueous solution, aluminum is supported. An anodized film can be formed on the body surface.
The conditions of the anodizing treatment cannot be determined unconditionally because they vary depending on the electrolytic solution used. In general, the concentration of the electrolytic solution is 1 to 80%, the liquid temperature is 5 to 70 ° C., the current density is 0.00. A range of 5 to 60 amperes / dm ² , a voltage of 1 to 100 V, and an electrolysis time of 10 to 100 seconds is appropriate.
Among these anodizing treatments, a method for anodizing at a high current density in sulfuric acid described in British Patent No. 1,412,768, and a method described in US Pat. No. 3,511,661, in particular. A method of anodizing phosphoric acid as an electrolytic bath is preferred.
The anodized film is preferably 1 to 10 g / m ² . If it is less than 1 g / m ² , the plate is likely to be damaged, and if it exceeds 10 g / m ² , a large amount of electric power is required for production, which is economically disadvantageous. Preferably, it is 1.5-7 g / m < ² >, More preferably, it is 2-5 g / m < ² >.

  Further, the support may be subjected to a sealing treatment after the graining treatment and the anodizing treatment. The sealing treatment is performed by immersing the support in a hot aqueous solution containing hot water and an inorganic salt or an organic salt, a steam bath, or the like. Further, the support may be subjected to a surface treatment such as a silicate treatment with an alkali metal silicate or an immersion treatment in an aqueous solution of potassium fluoride zirconate, phosphate or the like.

  For example, an image recording layer made of a photopolymerizable photosensitive composition is coated on a support (in the case of an aluminum plate, an aluminum plate that has been appropriately surface-treated as described above), and then, if necessary, By applying a protective layer, a lithographic printing plate precursor is formed. However, before coating the image recording layer, an organic or inorganic undercoat layer may be provided as required, or JP-A-7-159983. A sol-gel treatment for covalently bonding a functional group capable of causing an addition reaction by a radical as disclosed in No. 1 to the surface of the support may be performed.

Examples of the substance forming the organic undercoat layer include water-soluble resins such as polyvinylphosphonic acid, polymers and copolymers having a sulfonic acid group in the side chain, polyacrylic acid, yellow dye, amine salt and the like.
Specifically, examples of the organic compound used in the organic undercoat layer include phosphonic acids having an amino group such as carboxymethyl cellulose, dextrin, gum arabic, and 2-aminoethylphosphonic acid, and optionally having phenyl. Phosphonic acid, naphthylphosphonic acid, alkylphosphonic acid, glycerophosphonic acid, polyvinylphosphonic acid, organic phosphonic acid such as methylenediphosphonic acid and ethylenediphosphonic acid, phenylphosphonic acid which may have a substituent, naphthylphosphoric acid, alkyl Organic phosphoric acid such as phosphoric acid and glycerophosphoric acid, phenylphosphinic acid optionally having substituents, organic phosphinic acid such as naphthylphosphinic acid, alkylphosphinic acid and glycerophosphinic acid, amino acids such as glycine and β-alanine, And salts of triethanolamine Selected from hydrochlorides of amines having a hydroxyl group such as salt. You may use these in mixture of 2 or more types.

The organic undercoat layer can be provided by the following method. That is, a method in which water or an organic solvent such as methanol, ethanol, methyl ethyl ketone or the like, or a mixed solvent thereof is dissolved on a support, and a method of providing the substrate by drying, water, methanol, ethanol, methyl ethyl ketone, etc. The organic compound is dissolved in a solution of the above organic compound or a mixed solvent thereof to immerse the support so that the organic compound is adsorbed, and then washed with water and dried to provide an organic undercoat layer. Is the way. In the former method, a 0.005 to 10% by mass solution of an organic compound can be applied by various methods. For example, any method such as bar coater coating, spin coating, spray coating, or curtain coating may be used. In the latter method, the concentration of the solution is 0.01 to 20% by mass, preferably 0.05 to 5% by mass, the immersion temperature is 20 to 90 ° C., preferably 25 to 50 ° C., and the immersion time. Is 0.1 second to 20 minutes, preferably 2 seconds to 1 minute.
The solution used for this can also be used in the range of pH 1-12 by adjusting pH with basic substances, such as ammonia, triethylamine, potassium hydroxide, and acidic substances, such as hydrochloric acid and phosphoric acid. A yellow dye can also be added to improve the tone reproducibility of the lithographic printing plate precursor.
The coating amount after drying of the organic undercoat layer is suitably ² to 200 mg / m ² , preferably 5 to 100 mg / m ² . If the coating amount is less than 2 mg / m ² , sufficient printing durability may not be obtained. It is the same even if it is larger than 200 mg / m ² .

  Examples of the material used for the inorganic undercoat layer include inorganic salts such as cobalt acetate, nickel acetate, and potassium fluorotitanate. The method of providing the inorganic undercoat layer is the same as that of the organic undercoat layer described above.

  The undercoat layer preferably has a polymer or copolymer having any one of phosphonic acid groups, phosphoric acid groups and sulfonic acid groups in the side chain from the viewpoint of improving printing durability. In the case of a copolymer, the polymerization component having these groups is preferably contained in an amount of 10 to 90 mol%, more preferably 20 to 50 mol%. Furthermore, the copolymer preferably has an ethylenically unsaturated bond in the side chain. It is preferable to have 10 to 90 mol% of the polymerization component having an ethylenically unsaturated bond in the side chain, and more preferable to have 15 to 40 mol%.

(Image recording layer)
The image recording layer (hereinafter also referred to as photosensitive layer) of the lithographic printing plate precursor used in the present invention comprises, as basic components, (i) a sensitizing dye, (ii) a photopolymerization initiator, and (iii) an ethylenically unsaturated diester. An addition polymerizable compound having a heavy bond and (iv) a binder polymer having a structure represented by the general formula (I) in the side chain.

[Sensitizing dye]
The sensitizing dye used in the present invention is a dye capable of transferring absorbed laser light energy to the photopolymerization initiator by energy transfer or electron transfer.
The absorption wavelength is not particularly limited as long as it is a sensitizing dye having the above function, and is appropriately selected depending on the wavelength of the laser used for exposure. In the present invention, for example, sensitization having an absorption maximum in a wavelength range of 350 nm to 450 nm is used. A dye and the infrared absorber mentioned later can be mentioned.
Examples of the sensitizing dye having an absorption maximum in the wavelength range of 350 nm to 450 nm include, for example, merocyanine dyes represented by the following general formula (2), benzopyrans represented by the following general formula (3), coumarins, and the following general formula: Aromatic ketones represented by (4), anthracenes represented by the following general formula (5), and the like can be exemplified.

(In the formula (2), A represents an S atom or NR ₆ , R ₆ represents a monovalent non-metallic atomic group, and Y represents a basic nucleus of the dye in combination with an adjacent A and an adjacent carbon atom. It represents a nonmetallic atomic group to be formed, X ₁ and X ₂ each independently represent a monovalent nonmetallic atomic group, and X ₁ and X ₂ may be bonded to each other to form an acidic nucleus of the dye. )

(In the formula (3), = Z represents an oxo group, a thioxo group, an imino group or an alkylidene group represented by the partial structural formula (1 ′), and X ₁ and X ₂ are as defined in the general formula (2). And R _{7 to} R ₁₂ each independently represents a monovalent nonmetallic atomic group.)

(In the formula (4), Ar ₃ represents an aromatic group or heteroaromatic group which may have a substituent, and R ₁₃ represents a monovalent nonmetallic atomic group. Preferred R ₁₃ is aromatic. Group or heteroaromatic group, Ar ₃ and R ₁₃ may be bonded to each other to form a ring.)

(In Formula (5), X < ₃ >, X < ₄ >, R < ₁₄ > -R < ₂₁ > represents a monovalent nonmetallic atomic group each independently, and preferable X < ₃ >, X < ₄ > is an electron donation whose Hammett's substituent constant is negative. Sex group.)

In the general formulas (2) to (5), preferred examples of the monovalent nonmetallic atomic group represented by X ₁ to X ₄ and R ₆ to R ₂₁ include a hydrogen atom, an alkyl group (for example, a methyl group, Ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, hexadecyl group, octadecyl group, eicosyl group, isopropyl group, isobutyl group , S-butyl group, t-butyl group, isopentyl group, neopentyl group, 1-methylbutyl group, isohexyl group, 2-ethylhexyl group, 2-methylhexyl group, cyclohexyl group, cyclopentyl group, 2-norbornyl group, chloromethyl group , Bromomethyl group, 2-chloroethyl group, trifluoromethyl group, methoxymethyl group, methoxyethoxy Ethyl group, allyloxymethyl group, phenoxymethyl group, methylthiomethyl group, tolylthiomethyl group, ethylaminoethyl group, diethylaminopropyl group, morpholinopropyl group, acetyloxymethyl group, benzoyloxymethyl group, N-cyclohexylcarbamoyloxyethyl Group, N-phenylcarbamoyloxyethyl group, acetylaminoethyl group, N-methylbenzoylaminopropyl group, 2-oxoethyl group, 2-oxopropyl group, carboxypropyl group, methoxycarbonylethyl group, allyloxycarbonylbutyl group, chloro Phenoxycarbonylmethyl group, carbamoylmethyl group, N-methylcarbamoylethyl group, N, N-dipropylcarbamoylmethyl group, N- (methoxyphenyl) carbamoylethyl group, N-methyl Ru-N- (sulfophenyl) carbamoylmethyl group, sulfobutyl group, sulfonatobutyl group, sulfamoylbutyl group, N-ethylsulfamoylmethyl group, N, N-dipropylsulfamoylpropyl group, N-tolylsulfamoyl group Propyl group, N-methyl-N- (phosphonophenyl) sulfamoyloctyl group, phosphonobutyl group, phosphonatohexyl group, diethylphosphonobutyl group, diphenylphosphonopropyl group, methylphosphonobutyl group, methylphosphine group Onatobutyl group, tolylphosphonohexyl group, tolylphosphonatohexyl group, phosphonooxypropyl group, phosphonatoxybutyl group, benzyl group, phenethyl group, α-methylbenzyl group, 1-methyl-1-phenylethyl group, p-methylbenzyl group, syn Namyl group, allyl group, 1-propenylmethyl group, 2-butenyl group, 2-methylallyl group, 2-methylpropenylmethyl group, 2-propynyl group, 2-butynyl group, 3-butynyl group, etc.), aryl group (for example , Phenyl group, biphenyl group, naphthyl group, tolyl group, xylyl group, mesityl group, cumenyl group, chlorophenyl group, bromophenyl group, chloromethylphenyl group, hydroxyphenyl group, methoxyphenyl group, ethoxyphenyl group, phenoxyphenyl group, Acetoxyphenyl group, benzoyloxyphenyl group, methylthiophenyl group, phenylthiophenyl group, methylaminophenyl group, dimethylaminophenyl group, acetylaminophenyl group, carboxyphenyl group, methoxycarbonylphenyl group, ethoxycarbonylphenyl group, Noxycarbonylphenyl group, N-phenylcarbamoylphenyl group, nitrophenyl group, cyanophenyl group, sulfophenyl group, sulfonatophenyl group, phosphonophenyl group, phosphonatophenyl group, etc.), heteroaryl group (for example, thiophene, Thiathrene, furan, pyran, isobenzofuran, chromene, xanthene, phenoxazine, pyrrole, pyrazole, isothiazole, isoxazole, pyrazine, pyrimidine, pyridazine, indolizine, isoindolizine, indoyl, indazole, purine, quinolidine, isoquinoline, Phthalazine, naphthyridine, quinazoline, cinolin, pteridine, carbazole, carboline, phenanthrine, acridine, perimidine, phenanthroline, phthalazine, phenalzadi , Groups derived from heteroaryl rings such as phenoxazine, furazane, and phenoxazine), alkenyl groups (for example, vinyl group, 1-propenyl group, 1-butenyl group, cinnamyl group, 2-chloro-1-ethenyl group, etc.) ), Alkynyl groups (for example, ethynyl group, 1-propynyl group, 1-butynyl group, trimethylsilylethynyl group, etc.), halogen atoms (-F, -Br, -Cl, -I), hydroxyl groups, alkoxy groups, aryloxy groups , Mercapto group, alkylthio group, arylthio group, alkyldithio group, aryldithio group, amino group, N-alkylamino group, N, N-dialkylamino group, N-arylamino group, N, N-diarylamino group, N -Alkyl-N-arylamino group, acyloxy group, carbamoyloxy group, N-alkylcal Vamoyloxy group, N-arylcarbamoyloxy group, N, N-dialkylcarbamoyloxy group, N, N-diarylcarbamoyloxy group, N-alkyl-N-arylcarbamoyloxy group, alkylsulfoxy group, arylsulfoxy group, acylthio Group, acylamino group, N-alkylacylamino group, N-arylacylamino group, ureido group, N′-alkylureido group, N ′, N′-dialkylureido group, N′-arylureido group, N ′, N '-Diarylureido group, N'-alkyl-N'-arylureido group, N-alkylureido group, N-arylureido group, N'-alkyl-N-alkylureido group, N'-alkyl-N-arylureido N ′, N′-dialkyl-N-alkylureido group, N ′, '-Dialkyl-N-arylureido group, N'-aryl-N-alkylureido group, N'-aryl-N-arylureido group, N', N'-diaryl-N-alkylureido group, N ', N '-Diaryl-N-arylureido group, N'-alkyl-N'-aryl-N-alkylureido group, N'-alkyl-N'-aryl-N-arylureido group, alkoxycarbonylamino group, aryloxycarbonyl Amino group, N-alkyl-N-alkoxycarbonylamino group, N-alkyl-N-aryloxycarbonylamino group, N-aryl-N-alkoxycarbonylamino group, N-aryl-N-aryloxycarbonylamino group, formyl Group, acyl group, carboxyl group, alkoxycarbonyl group, aryloxycal Nyl group, carbamoyl group, N-alkylcarbamoyl group, N, N-dialkylcarbamoyl group, N-arylcarbamoyl group, N, N-diarylcarbamoyl group, N-alkyl-N-arylcarbamoyl group, alkylsulfinyl group, arylsulfinyl group Group, alkylsulfonyl group, arylsulfonyl group, sulfo group (—SO ₃ H) and its conjugate base group (hereinafter referred to as sulfonate group), alkoxysulfonyl group, aryloxysulfonyl group, sulfinamoyl group, N-alkylsulfinamoyl Group, N, N-dialkylsulfinamoyl group, N-arylsulfinamoyl group, N, N-diarylsulfinamoyl group, N-alkyl-N-arylsulfinamoyl group, sulfamoyl group, N-alkylsulfa Moyl group, N, N- Dialkylsulfamoyl group, N- aryl sulfamoyl group, N, N- diaryl sulfamoyl group, N- alkyl -N- arylsulfamoyl group, a phosphono group (-PO ₃ H ₂₎ and its conjugated base group (Hereinafter referred to as phosphonate group), dialkyl phosphono group (—PO ₃ (alkyl) ₂ ), diaryl phosphono group (—PO ₃ (aryl) ₂ ), alkylaryl phosphono group (—PO ₃ (alkyl) ( aryl)), monoalkyl phosphono group (—PO ₃ H (alkyl)) and its conjugate base group (hereinafter referred to as alkyl phosphonate group), monoaryl phosphono group (—PO ₃ H (aryl)) and its conjugated base group (hereinafter referred to as aryl phosphonophenyl group), phosphonooxy group (-OPO ₃ H ₂₎ and its conjugated base group (hereinafter referred to as phosphonophenyl group), dialkyl Onookishi group _{(-OPO 3 (alkyl) 2)} , diaryl phosphonooxy group _{(-OPO 3 (aryl) 2)} , alkylaryl phosphonooxy group _{(-OPO 3 (alkyl) (aryl} )), monoalkyl phosphonooxy oxy Group (—OPO ₃ H (alkyl)) and its conjugate base group (hereinafter referred to as alkylphosphonatooxy group), monoarylphosphonooxy group (—OPO ₃ H (aryl)) and its conjugate base group (hereinafter, Aryl phosphonateoxy group), cyano group, nitro group, and the like, and among the above monovalent non-metallic atomic groups, hydrogen atom, alkyl group, aryl group, halogen atom, alkoxy group, acyl group are Particularly preferred.

  Examples of the basic nucleus of the dye formed by Y in the general formula (2) in cooperation with the adjacent A and adjacent carbon atoms include 5-, 6-, and 7-membered nitrogen-containing or sulfur-containing heterocyclic rings. Is a 5- or 6-membered heterocyclic ring.

  Examples of nitrogen-containing heterocycles constitute the basic nucleus in merocyanine dyes described in, for example, LGBrooker et al., J. Am. Chem. Soc., 73, 5326-5358 (1951) and references Any known material can be suitably used. Specific examples include thiazoles (for example, thiazole, 4-methylthiazole, 4-phenylthiazole, 5-methylthiazole, 5-phenylthiazole, 4,5-dimethylthiazole, 4,5-diphenylthiazole, 4,5- Di (p-methoxyphenylthiazole), 4- (2-thienyl) thiazole, etc.), benzothiazoles (for example, benzothiazole, 4-chlorobenzothiazole, 5-chlorobenzothiazole, 6-chlorobenzothiazole, 7-chloro Benzothiazole, 4-methylbenzothiazole, 5-methylbenzothiazole, 6-methylbenzothiazole, 5-bromobenzothiazole, 4-phenylbenzothiazole, 5-phenylbenzothiazole, 4-methoxybenzothiazole, 5-methoxybenzothiazole Z , 6-methoxybenzothiazole, 5-iodobenzothiazole, 6-iodobenzothiazole, 4-ethoxybenzothiazole, 5-ethoxybenzothiazole, tetrahydrobenzothiazole, 5,6-dimethoxybenzothiazole, 5,6-dioxy Methylenebenzothiazole, 5-hydroxybenzothiazole, 6-hydroxybenzothiazole, 6-dimethylaminobenzothiazole, 5-ethoxycarbonylbenzothiazole, etc.), naphthothiazoles (for example, naphtho [1,2] thiazole, naphtho [2, 1] thiazole, 5-methoxynaphtho [2,1] thiazole, 5-ethoxynaphtho [2,1] thiazole, 8-methoxynaphtho [1,2] thiazole, 7-methoxynaphtho [1,2] thiazole, etc.) Tianafteno ', 6', 4,5-thiazole (for example, 4'-methoxythianaphtheno-7 ', 6', 4,5-thiazole, etc.), oxazole (for example, 4-methyloxazole, 5-methyloxazole, 4-phenyloxazole, 4,5-diphenyloxazole, 4-ethyloxazole, 4,5-dimethyloxazole, 5-phenyloxazole, etc.), benzoxazoles (benzoxazole, 5-chlorobenzoxazole, 5-methylbenzoxazole, 5-phenylbenzoxazole, 6-methylbenzoxazole, 5,6-dimethylbenzoxazole, 4,6-dimethylbenzoxazole, 6-methoxybenzoxazole, 5-methoxybenzoxazole, 4-ethoxybenzoxazole, 5-chlorobenzo Oxazole, 6-methoxybenzoxazole, 5-hydroxybenzoxazole, 6-hydroxybenzoxazole, etc.), naphthoxazoles (eg, naphtho [1,2] oxazole, naphtho [2,1] oxazole, etc.), selenazoles (eg, , 4-methylselenazole, 4-phenylselenazole, etc.), benzoselenazoles (for example, benzoselenazole, 5-chlorobenzoselenazole, 5-methoxybenzoselenazole, 5-hydroxybenzoselenazole, tetrahydrobenzoselena) Sol etc.), naphthoselenazoles (eg naphtho [1,2] selenazole, naphtho [2,1] selenazole etc.), thiazolines (eg thiazoline, 4-methylthiazoline etc.), quinolines (eg quinoline, 3-methyl Norin, 5-methylquinoline, 7-methylquinoline, 8-methylquinoline, 6-chloroquinoline, 8-chloroquinoline, 6-methoxyquinoline, 6-ethoxyquinoline, 6-hydroxyquinoline, 8-hydroxyquinoline, etc.), isoquinoline (Eg, isoquinoline, 3,4-dihydroisoquinoline, etc.), benzimidazoles (eg, 1,3-diethylbenzimidazole, 1-ethyl-3-phenylbenzimidazole, etc.), 3,3-dialkylindolenins ( For example, 3,3-dimethylindolenine, 3,3,5, -trimethylindolenine, 3,3,7, -trimethylindolenine, etc.), pyridines (for example, pyridine, 5-methylpyridine, etc.), etc. be able to.

Examples of the sulfur-containing heterocycle include a dithiol partial structure in dyes described in JP-A-3-296759.
Specific examples include benzodithiols (for example, benzodithiol, 5-t-butylbenzodithiol, 5-methylbenzodithiol, etc.), naphthodithiols (for example, naphtho [1,2] dithiol, naphtho [2,1] Dithiols, etc.), dithiols (for example, 4,5-dimethyldithiols, 4-phenyldithiols, 4-methoxycarbonyldithiols, 4,5-dimethoxycarbonyldithiols, 4,5-ditrifluoromethyldithiols, 4, 5-dicyanodithiol, 4-methoxycarbonylmethyldithiol, 4-carboxymethyldithiol, etc.).

  As mentioned above, the description used for the description of the heterocyclic ring described above has conventionally used the name of the heterocyclic mother skeleton for convenience, but in the case of the basic skeleton partial structure of the sensitizing dye, for example, in the case of the benzothiazole skeleton It is introduced as an alkylidene-type substituent with one degree of unsaturation, such as a 3-substituted-2 (3H) -benzothiazolylidene group.

  Of the sensitizing dyes having an absorption maximum in the wavelength range of 350 nm to 450 nm, a dye more preferable from the viewpoint of high sensitivity is a dye represented by the following general formula (1).

(In the general formula (1), A represents an aromatic ring or a hetero ring which may have a substituent, and X represents an oxygen atom, a sulfur atom or N- (R ₃ ). R ₁ , R ₂ and R ₃ each independently represents a monovalent nonmetallic atomic group, and A and R ₁ or R ₂ and R ₃ may be bonded to each other to form an aliphatic or aromatic ring. .)

The general formula (1) will be described in more detail. R ₁ , R ₂ and R ₃ are each independently a monovalent nonmetallic atomic group, preferably a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted aryl group. Represents a substituted or unsubstituted aromatic heterocyclic residue, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted alkylthio group, a hydroxyl group, or a halogen atom.

Preferable examples of R ₁ , R ₂ and R ₃ will be specifically described. Examples of preferable alkyl groups include linear, branched, and cyclic alkyl groups having 1 to 20 carbon atoms, and specific examples thereof include methyl, ethyl, propyl, and butyl. Group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, hexadecyl group, octadecyl group, eicosyl group, isopropyl group, isobutyl group, s-butyl group, t -Butyl group, isopentyl group, neopentyl group, 1-methylbutyl group, isohexyl group, 2-ethylhexyl group, 2-methylhexyl group, cyclohexyl group, cyclopentyl group, 2-norbornyl group can be mentioned. Of these, linear alkyl groups having 1 to 12 carbon atoms, branched alkyl groups having 3 to 12 carbon atoms, and cyclic alkyl groups having 5 to 10 carbon atoms are more preferable.

  As the substituent of the substituted alkyl group, a monovalent nonmetallic atomic group excluding hydrogen is used, and preferred examples include a halogen atom (—F, —Br, —Cl, —I), a hydroxyl group, an alkoxy group, Aryloxy group, mercapto group, alkylthio group, arylthio group, alkyldithio group, aryldithio group, amino group, N-alkylamino group, N, N-dialkylamino group, N-arylamino group, N, N-diarylamino group N-alkyl-N-arylamino group, acyloxy group, carbamoyloxy group, N-alkylcarbamoyloxy group, N-arylcarbamoyloxy group, N, N-dialkylcarbamoyloxy group, N, N-diarylcarbamoyloxy group, N-alkyl-N-arylcarbamoyloxy group, alkylsulfoxy group, Reel sulphoxide group, an acylthio group, an acylamino group, N- alkylacylamino group, N- arylacylamino group, a ureido group, N'- alkylureido group, N ', N'- dialkyl ureido group,

  N'-arylureido group, N ', N'-diarylureido group, N'-alkyl-N'-arylureido group, N-alkylureido group, N-arylureido group, N'-alkyl-N-alkylureido Group, N′-alkyl-N-arylureido group, N ′, N′-dialkyl-N-alkylureido group, N ′, N′-dialkyl-N-arylureido group, N′-aryl-N-alkylureido group Group, N′-aryl-N-arylureido group, N ′, N′-diaryl-N-alkylureido group, N ′, N′-diaryl-N-arylureido group, N′-alkyl-N′-aryl -N-alkylureido group, N'-alkyl-N'-aryl-N-arylureido group, alkoxycarbonylamino group, aryloxycarbonyl Mino group, N-alkyl-N-alkoxycarbonylamino group, N-alkyl-N-aryloxycarbonylamino group, N-aryl-N-alkoxycarbonylamino group, N-aryl-N-aryloxycarbonylamino group, acyl Group, carboxyl group,

Alkoxycarbonyl group, aryloxycarbonyl group, carbamoyl group, N-alkylcarbamoyl group, N, N-dialkylcarbamoyl group, N-arylcarbamoyl group, N, N-diarylcarbamoyl group, N-alkyl-N-arylcarbamoyl group, An alkylsulfinyl group, an arylsulfinyl group, an alkylsulfonyl group, an arylsulfonyl group, a sulfo group (—SO ₃ H) and its conjugate base group (hereinafter referred to as a sulfonate group), an alkoxysulfonyl group, an aryloxysulfonyl group, a sulfinamoyl group, N-alkylsulfinamoyl group, N, N-dialkylsulfinamoyl group, N-arylsulfinamoyl group, N, N-diarylsulfinamoyl group, N-alkyl-N-arylsulfinamoyl group, sulfamoyl N-alkylsulfamoyl group, N, N-dialkylsulfamoyl group, N-arylsulfamoyl group, N, N-diarylsulfamoyl group, N-alkyl-N-arylsulfamoyl group, phosphono Group (—PO ₃ H ₂ ) and its conjugate base group (hereinafter referred to as phosphonate group),

Dialkyl phosphono group (—PO ₃ (alkyl) ₂ ), diaryl phosphono group (—PO ₃ (aryl) ₂ ), alkylaryl phosphono group (—PO ₃ (alkyl) (aryl)), monoalkyl phosphono group (—PO ₃ H (alkyl)) and its conjugate base group (hereinafter referred to as alkylphosphonate group), monoarylphosphono group (—PO ₃ H (aryl)) and its conjugate base group (hereinafter referred to as arylphosphonate) Group), phosphonooxy group (—OPO ₃ H ₂ ) and its conjugate base group (hereinafter referred to as phosphonatoxy group), dialkylphosphonooxy group (—OPO ₃ (alkyl) ₂ ), diarylphosphono Oxy group (—OPO ₃ (aryl) ₂ ), alkylaryl phosphonooxy group (—OPO ₃ (alkyl) (aryl)), monoalkyl phosphonooxy group (—OPO ₃ H (alkyl)) and its conjugate base group ( After, referred to as alkyl phosphonophenyl group), monoaryl phosphonooxy group (-OPO ₃ H (aryl)) and its conjugated base group (hereinafter referred to as aryl phosphite Hona preparative group), a cyano group, a nitro group, an aryl Group, heteroaryl group, alkenyl group, alkynyl group.

  Specific examples of the alkyl group in these substituents include the above-described alkyl groups, and specific examples of the aryl group include a phenyl group, a biphenyl group, a naphthyl group, a tolyl group, a xylyl group, a mesityl group, and a cumenyl group. , Chlorophenyl group, bromophenyl group, chloromethylphenyl group, hydroxyphenyl group, methoxyphenyl group, ethoxyphenyl group, phenoxyphenyl group, acetoxyphenyl group, benzoyloxyphenyl group, methylthiophenyl group, phenylthiophenyl group, methylamino Phenyl group, dimethylaminophenyl group, acetylaminophenyl group, carboxyphenyl group, methoxycarbonylphenyl group, ethoxycarbonylphenyl group, phenoxycarbonylphenyl group, N-phenylcarbamoylphenyl group, nitrophene Group, cyanophenyl group, sulfophenyl group, sulfonatophenyl group, phosphonophenyl phenyl group, and a phosphonophenyl phenyl group.

  As the heteroaryl group, a monocyclic or polycyclic aromatic ring group containing at least one of nitrogen, oxygen, and sulfur atoms is used. Examples of particularly preferred heteroaryl groups include thiophene, thiathrene, furan, Pyran, isobenzofuran, chromene, xanthene, phenoxazine, pyrrole, pyrazole, isothiazole, isoxazole, pyrazine, pyrimidine, pyridazine, indolizine, isoindolizine, indoyl, indazole, purine, quinolidine, isoquinoline, phthalazine, naphthyridine, Heteroarytes such as quinazoline, sinoline, pteridine, carbazole, carboline, phenanthrine, acridine, perimidine, phenanthrolin, phthalazine, phenazazine, phenoxazine, furazane, phenoxazine Mentioned groups derived from Le ring, it may be benzo-fused or may have a substituent.

Examples of the alkenyl group include a vinyl group, 1-propenyl group, 1-butenyl group, cinnamyl group, 2-chloro-1-ethenyl group and the like. Examples of the alkynyl group include ethynyl group and 1-propynyl group. , 1-butynyl group, trimethylsilylethynyl group and the like. Examples of G ₁ in the acyl group (.BR> F ₁ CO—) include hydrogen and the above alkyl groups and aryl groups. Among these substituents, even more preferred are halogen atoms (—F, —Br, —Cl, —I), alkoxy groups, aryloxy groups, alkylthio groups, arylthio groups, N-alkylamino groups, N, N— Dialkylamino group, acyloxy group, N-alkylcarbamoyloxy group, N-arylcarbamoyloxy group, acylamino group, acyl group, carboxyl group, alkoxycarbonyl group, aryloxycarbonyl group, carbamoyl group, N-alkylcarbamoyl group, N, N-dialkylcarbamoyl group, N-arylcarbamoyl group, N-alkyl-N-arylcarbamoyl group, sulfo group, sulfonate group, sulfamoyl group, N-alkylsulfamoyl group, N, N-dialkylsulfamoyl group, N An arylsulfamoyl group, N Alkyl-N-arylsulfamoyl group, phosphono group, phosphonate group, dialkyl phosphono group, diaryl phosphono group, monoalkyl phosphono group, alkyl phosphonate group, monoaryl phosphono group, aryl phosphonate group, phosphono Examples thereof include an oxy group, a phosphonatooxy group, an aryl group, and an alkenyl group.

  On the other hand, examples of the alkylene group in the substituted alkyl group include divalent organic residues obtained by removing any one of the hydrogen atoms on the alkyl group having 1 to 20 carbon atoms. Can include linear alkylene groups having 1 to 12 carbon atoms, branched structures having 3 to 12 carbon atoms, and cyclic alkylene groups having 5 to 10 carbon atoms.

Specific examples of preferred substituted alkyl groups as R ₁ , R ₂ and R ₃ obtained by combining the above substituents with an alkylene group include chloromethyl group, bromomethyl group, 2-chloroethyl group, trifluoromethyl group, methoxymethyl Group, methoxyethoxyethyl group, allyloxymethyl group, phenoxymethyl group, methylthiomethyl group, tolylthiomethyl group, ethylaminoethyl group, diethylaminopropyl group, morpholinopropyl group, acetyloxymethyl group, benzoyloxymethyl group, N- Cyclohexylcarbamoyloxyethyl group, N-phenylcarbamoyloxyethyl group, acetylaminoethyl group, N-methylbenzoylaminopropyl group, 2-oxoethyl group, 2-oxopropyl group, carboxypropyl group, methoxycarbo Nylethyl group, allyloxycarbonylbutyl group, chlorophenoxycarbonylmethyl group, carbamoylmethyl group, N-methylcarbamoylethyl group, N, N-dipropylcarbamoylmethyl group, N- (methoxyphenyl) carbamoylethyl group, N-methyl- N- (sulfophenyl) carbamoylmethyl group,

  Sulfobutyl group, sulfonatobutyl group, sulfamoylbutyl group, N-ethylsulfamoylmethyl group, N, N-dipropylsulfamoylpropyl group, N-tolylsulfamoylpropyl group, N-methyl-N- (phosphono Phenyl) sulfamoyloctyl group, phosphonobutyl group, phosphonatohexyl group, diethylphosphonobutyl group, diphenylphosphonopropyl group, methylphosphonobutyl group, methylphosphonatobutyl group, tolylphosphonohexyl group, tolylphosphine group Onatohexyl group, phosphonooxypropyl group, phosphonatoxybutyl group, benzyl group, phenethyl group, α-methylbenzyl group, 1-methyl-1-phenylethyl group, p-methylbenzyl group, cinnamyl group, allyl group, 1-propenylmethyl group, 2- Thenyl group, 2-methylallyl group, 2-methyl propenyl methyl group, 2-propynyl group, 2-butynyl, 3-butynyl, and the like.

Specific examples of preferred aryl groups as R ₁ , R ₂ and R ₃ include those in which 1 to 3 benzene rings form a condensed ring, and those in which a benzene ring and a 5-membered unsaturated ring form a condensed ring. Specific examples include a phenyl group, a naphthyl group, an anthryl group, a phenanthryl group, an indenyl group, an acenaphthenyl group, and a fluorenyl group, and among these, a phenyl group and a naphthyl group are more preferable. .

Specific examples of preferred substituted aryl groups as R ₁ , R ₂ and R ₃ include those having a monovalent non-metallic atomic group excluding hydrogen as a substituent on the ring-forming carbon atom of the aryl group described above. . Examples of preferred substituents include the alkyl groups, substituted alkyl groups, and those previously shown as substituents in the substituted alkyl group. Preferred examples of such a substituted aryl group include biphenyl group, tolyl group, xylyl group, mesityl group, cumenyl group, chlorophenyl group, bromophenyl group, fluorophenyl group, chloromethylphenyl group, trifluoromethylphenyl group. Hydroxyphenyl group, methoxyphenyl group, methoxyethoxyphenyl group, allyloxyphenyl group, phenoxyphenyl group, methylthiophenyl group, tolylthiophenyl group, ethylaminophenyl group, diethylaminophenyl group, morpholinophenyl group, acetyloxyphenyl group, Benzoyloxyphenyl group, N-cyclohexylcarbamoyloxyphenyl group, N-phenylcarbamoyloxyphenyl group,

  Acetylaminophenyl group, N-methylbenzoylaminophenyl group, carboxyphenyl group, methoxycarbonylphenyl group, allyloxycarbonylphenyl group, chlorophenoxycarbonylphenyl group, carbamoylphenyl group, N-methylcarbamoylphenyl group, N, N-di Propylcarbamoylphenyl group, N- (methoxyphenyl) carbamoylphenyl group, N-methyl-N- (sulfophenyl) carbamoylphenyl group, sulfophenyl group, sulfonatophenyl group, sulfamoylphenyl group, N-ethylsulfamoyl Phenyl group, N, N-dipropylsulfamoylphenyl group, N-tolylsulfamoylphenyl group, N-methyl-N- (phosphonophenyl) sulfamoylphenyl group, phosphonophenyl group, phos Onatophenyl group, diethylphosphonophenyl group, diphenylphosphonophenyl group, methylphosphonophenyl group, methylphosphonatophenyl group, tolylphosphonophenyl group, tolylphosphonatophenyl group, allylphenyl group, 1-propenylmethylphenyl group 2-butenylphenyl group, 2-methylallylphenyl group, 2-methylpropenylphenyl group, 2-propynylphenyl group, 2-butynylphenyl group, 3-butynylphenyl group, and the like.

Specific examples of the substituted or unsubstituted alkenyl group and the substituted or unsubstituted aromatic heterocyclic residue that are preferable as R ₁ , R _2, and R ₃ are the same as those described above for the alkenyl group and heteroaryl group. Things can be mentioned. In addition, examples of the substituted or unsubstituted alkoxy group and the substituted or unsubstituted alkylthio group that are preferable as R ₁ , R _2, and R ₃ include the aforementioned alkyl groups. Examples of the substituent for these groups include the same substituents as those in the aforementioned substituted alkyl group.

Next, A in the general formula (1) will be described. A represents an aromatic ring group or a heterocyclic group which may have a substituent, and specific examples of the aromatic ring group or the heterocyclic group which may have a substituent include those in the general formula (1). Examples are the same as the aryl group and heteroaryl group described for R ₁ , R ₂ and R ₃ .

  The sensitizing dye represented by the general formula (1) of the present invention is a condensation reaction of an acidic nucleus having an acidic nucleus or an active methylene group as shown above with a substituted or unsubstituted aromatic ring or heterocyclic ring. Obtained by. Specifically, it can be synthesized with reference to the description of JP-B-59-28329.

  Preferred specific examples (D1) to (D42) of the compound represented by the general formula (1) are shown below. In addition, an isomer with a double bond connecting an acidic nucleus and a basic nucleus is not limited to either isomer.

  Sensitizing dyes have different extinction coefficients depending on the structure, so the amount added varies depending on the structure of the sensitizing dye used. The addition amount is suitably such that the absorbance of the photosensitive layer with respect to the laser emission wavelength is 0.6 or less. Preferably, the absorbance is in the range of 0.05 to 0.55, more preferably in the range of 0.1 to 0.3, and even more preferably in the range of 0.1 to 0.45 Amount.

  The infrared absorber is a component used to increase sensitivity to an infrared laser. The infrared absorber has a function of converting absorbed infrared rays into heat. The infrared absorber used in the present invention is preferably a dye or pigment having an absorption maximum at a wavelength of 760 to 1200 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 Is mentioned.

  Examples of preferable dyes include cyanine dyes described in JP-A-58-125246, JP-A-59-84356, JP-A-60-78787, JP-A-58-173696, Methine dyes described in JP-A Nos. 58-181690 and 58-194595, JP-A-58-112793, JP-A-58-224793, JP-A-59-48187, JP-A Naphthoquinone dyes described in JP-A-59-73996, JP-A-60-52940, JP-A-60-63744, etc., squarylium dyes described in JP-A-58-112792, etc., British Patent No. And cyanine dyes described in the specification of 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, 59-84248, 59-84249, 59-146063, 59-146061, pyranyl compounds described in JP-A-59-216146, cyanine dyes described in US It is disclosed in the pentamethine thiopyrylium salt described in Japanese Patent No. 4,283,475, and Japanese Patent Publication Nos. 5-13514 and 5-19702. Pyrylium compounds are also preferably used. Another example of a preferable dye is a near-infrared absorbing dye described in US Pat. No. 4,756,993 as formulas (I) and (II).

  Other preferable examples of the infrared absorbing dye include specific indolenine cyanine dyes described in JP-A-2002-278057 as exemplified below.

  Particularly preferred among these dyes are cyanine dyes, squarylium dyes, pyrylium salts, nickel thiolate complexes, and indolenine cyanine dyes. Further, cyanine dyes and indolenine cyanine dyes are preferred, and one particularly preferred example is a cyanine dye represented by the following general formula (I).

In the general formula (I), X ¹ represents a hydrogen atom, a halogen atom, -NPh _2, X ² -L ¹ or a group shown below. Here, X ² represents an oxygen atom, a nitrogen atom, or a sulfur atom, and L ¹ represents a hydrocarbon group having 1 to 12 carbon atoms, an aromatic ring having a hetero atom, or 1 to 1 carbon atom containing a hetero atom. 12 hydrocarbon groups are shown. In addition, a hetero atom here shows N, S, O, a halogen atom, and Se.

(Wherein, Xa ^- is Za described later ^- is synonymous with, R ^a represents a hydrogen atom, an alkyl group, an aryl group, a substituted or unsubstituted amino group, substituted or unsubstituted amino group and a halogen atom.)

R ¹ and R ² each independently represents a hydrocarbon group having 1 to 12 carbon atoms. From the storage stability of the photosensitive layer coating solution, R ¹ and R ² are preferably hydrocarbon groups having 2 or more carbon atoms, and R ¹ and R ² are bonded to each other to form a 5-membered ring or It is particularly preferable that a 6-membered ring is formed.

Ar ¹ and Ar ² may be the same or different and each represents an aromatic hydrocarbon group which may have a substituent. Preferred aromatic hydrocarbon groups include a benzene ring and a naphthalene ring. Moreover, as a preferable substituent, a C12 or less hydrocarbon group, a halogen atom, and a C12 or less alkoxy group are mentioned. Y ¹ and Y ² may be the same or different and each represents a sulfur atom or a dialkylmethylene group having 12 or less carbon atoms. R ³ and R ⁴ may be the same or different and each represents a hydrocarbon group having 20 or less carbon atoms which may have a substituent. Preferred substituents include alkoxy groups having 12 or less carbon atoms, carboxyl groups, and sulfo groups. R ⁵ , R ⁶ , R ⁷ and R ⁸ may be the same or different and each represents a hydrogen atom or a hydrocarbon group having 12 or less carbon atoms. From the availability of raw materials, a hydrogen atom is preferred. Za ⁻ represents a counter anion. However, Za ⁻ is not necessary when the cyanine dye represented by formula (I) has an anionic substituent in its structure and neutralization of charge is not necessary. Preferred Za ⁻ is a halogen ion, a perchlorate ion, a tetrafluoroborate ion, a hexafluorophosphate ion, and a sulfonate ion, particularly preferably a perchlorate ion, a hexagonal salt, in view of the storage stability of the photosensitive layer coating solution. Fluorophosphate ion and aryl sulfonate ion.

  Specific examples of the cyanine dye represented by formula (I) that can be suitably used in the present invention include those described in paragraph numbers [0017] to [0019] of JP-A No. 2001-133969. be able to.

  Further, other particularly preferable examples include specific indolenine cyanine dyes described in JP-A-2002-278057 described above.

  Examples of the pigment used in the present invention include commercially available pigments and color index (CI) manual, “Latest Pigment Handbook” (edited by Japan Pigment Technology 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 , Loso pigments, nitro pigments, natural materials, fluorescent pigments, inorganic pigments, carbon black and the like can be used. Among these pigments, carbon black is preferable.

  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 to 10 μm, more preferably in the range of 0.05 to 1 μm, and particularly preferably in the range of 0.1 to 1 μm. Within this range, good stability and uniformity of the pigment dispersion in the photosensitive 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).

  These infrared absorbers can be added by being encapsulated in microcapsules.

  As the addition amount, it is preferable to add so that the absorbance at the maximum absorption wavelength in the wavelength range of 760 nm to 1200 nm of the photosensitive layer is in the range of 0.3 to 1.3 by the reflection measurement method, more preferably, It is in the range of 0.4 to 1.2. Within this range, a uniform polymerization reaction proceeds in the depth direction of the photosensitive layer, and good film strength of the image area and adhesion to the support can be obtained.

  The absorbance of the photosensitive layer can be adjusted by the amount of infrared absorber added to the photosensitive layer and the thickness of the photosensitive layer. Absorbance can be measured by a conventional method. As a measuring method, for example, on a reflective support such as aluminum, a photosensitive layer having a thickness appropriately determined in a range where the coating amount after drying is necessary as a lithographic printing plate is formed, and the reflection density is measured by an optical densitometer. And a method of measuring with a spectrophotometer by a reflection method using an integrating sphere.

(Photopolymerization initiator)
The photopolymerization initiator used in the photosensitive layer of the present invention is a compound that initiates and accelerates the polymerization of a compound having a polymerizable unsaturated group by generating radicals by light or thermal energy. Such a radical polymerization initiator can be appropriately selected from known radical polymerization initiators and compounds having a bond having a small bond dissociation energy.
Examples of the radical polymerization initiator include organic halogen compounds, carbonyl compounds, organic peroxides, azo compounds, azide compounds, metallocene compounds, hexaarylbiimidazole compounds, organic boron compounds, disulfone compounds, oxime ester compounds, oniums. A salt compound is mentioned.

  Specific examples of the organic halogen compound include Wakabayashi et al., “Bull Chem. Soc Japan” 42, 2924 (1969), US Pat. No. 3,905,815, Japanese Patent Publication No. 46-4605, JP 48-36281, JP 53-133428, JP 55-3070, JP 60-239736, JP 61-169835, JP 61-169837, JP 62- 58241, JP-A 62-212401, JP-A 63-70243, JP-A 63-298339, P. The compound as described in Hutt, "Journal of Heterocyclic Chemistry", 1 (No. 3) (1970) is mentioned. Of these, oxazole compounds and S-triazine compounds substituted with a trihalomethyl group are preferred.

  More preferable examples include s-triazine derivatives in which at least one mono, di, or trihalogen-substituted methyl group is bonded to the s-triazine ring, and oxadiazole derivatives in which the oxadiazole ring is bonded. Specifically, for example, 2,4,6-tris (monochloromethyl) -s-triazine, 2,4,6-tris (dichloromethyl) -s-triazine, 2,4,6-tris (trichloromethyl) -S-triazine, 2-methyl-4,6-bis (trichloromethyl) -s-triazine, 2-n-propyl-4,6-bis (trichloromethyl) -s-triazine, 2- (α, α, β-trichloroethyl) -4,6-bis (trichloromethyl) -s-triazine, 2- (3,4-epoxyphenyl) -4,6-bis (trichloromethyl) -s-triazine, 2- [1- (P-methoxyphenyl) -2,4-butadienyl] -4,6-bis (trichloromethyl) -s-triazine, 2-styryl-4,6-bis (trichloromethyl) -s-triazine, 2- ( -Methoxystyryl) -4,6-bis (trichloromethyl) -s-triazine, 2- (pi-propyloxystyryl) -4,6-bis (trichloromethyl) -s-triazine, 2- (p- Tolyl) -4,6-bis (trichloromethyl) -s-triazine, 2- (4-methoxynaphthyl) -4,6-bis (trichloromethyl) -s-triazine, 2-phenylthio-4,6-bis ( Trichloromethyl) -s-triazine, 2-benzylthio-4,6-bis (trichloromethyl) -s-triazine, 2,4,6-tris (dibromomethyl) -s-triazine, 2,4,6-tris ( Tribromomethyl) -s-triazine, 2-methyl-4,6-bis (tribromomethyl) -s-triazine, 2-methoxy-4,6-bis (tribromomethyl) Etc. -s- triazine and the following compounds.

  Examples of the carbonyl compound include benzophenone, Michler ketone, 2-methylbenzophenone, 3-methylbenzophenone, 4-methylbenzophenone, 2-chlorobenzophenone, 4-bromobenzophenone, 2-carboxybenzophenone and other benzophenone derivatives, 2,2-dimethoxy- 2-phenylacetophenone, 2,2-diethoxyacetophenone, 1-hydroxycyclohexyl phenyl ketone, α-hydroxy-2-methylphenylpropanone, 1-hydroxy-1-methylethyl- (p-isopropylphenyl) ketone, 1- Hydroxy-1- (p-dodecylphenyl) ketone, 2-methyl- (4 ′-(methylthio) phenyl) -2-morpholino-1-propanone, 1,1,1-trichloromethyl- (p-butylphenyl) Acetophenone derivatives such as ketones, thioxanthone derivatives such as thioxanthone, 2-ethylthioxanthone, 2-isopropylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, p- Examples thereof include benzoic acid ester derivatives such as ethyl dimethylaminobenzoate and ethyl p-diethylaminobenzoate.

  As the azo compound, for example, an azo compound described in JP-A-8-108621 can be used.

  Examples of the organic peroxide include trimethylcyclohexanone peroxide, acetylacetone peroxide, 1,1-bis (tert-butylperoxy) -3,3,5-trimethylcyclohexane, 1,1-bis (tert-butyl). Peroxy) cyclohexane, 2,2-bis (tert-butylperoxy) butane, tert-butyl hydroperoxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, 2,5-dimethylhexane-2,5-dihydro Peroxide, 1,1,3,3-tetramethylbutyl hydroperoxide, tert-butylcumyl peroxide, dicumyl peroxide, 2,5-dimethyl-2,5-di (tert-butylperoxy) hexane, 2, -Oxanoyl peroxide, succinic peroxide, benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, diisopropyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, di-2-ethoxyethyl peroxydicarbonate , Dimethoxyisopropyl peroxycarbonate, di (3-methyl-3-methoxybutyl) peroxydicarbonate, tert-butyl peroxyacetate, tert-butyl peroxypivalate, tert-butyl peroxyneodecanoate, tert- Butyl peroxyoctanoate, tert-butyl peroxylaurate, tersyl carbonate, 3,3 ′, 4,4′-tetra- (t-butylperoxycarbonyl) benzophenone, 3,3 ′, 4,4 ′ − Tra- (t-hexylperoxycarbonyl) benzophenone, 3,3 ′, 4,4′-tetra- (p-isopropylcumylperoxycarbonyl) benzophenone, carbonyldi (t-butylperoxydihydrogen diphthalate), carbonyl And di (t-hexylperoxydihydrogen diphthalate).

  Examples of the metallocene compound include JP-A-59-152396, JP-A-61-151197, JP-A-63-41484, JP-A-2-249, JP-A-2-4705, Various titanocene compounds described in JP-A-5-83588, such as di-cyclopentadienyl-Ti-bis-phenyl, di-cyclopentadienyl-Ti-bis-2,6-difluorophen-1-yl, Di-cyclopentadienyl-Ti-bis-2,4-di-fluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2,4,6-trifluorophen-1-yl, di- -Cyclopentadienyl-Ti-bis-2,3,5,6-tetrafluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2,3,4,5,6-penta Fluorophen-1-yl, di-methylcyclopentadienyl-Ti-bis-2,6-difluorophen-1-yl, di-methylcyclopentadienyl-Ti-bis-2,4,6-trifluoropheny -1-yl, di-methylcyclopentadienyl-Ti-bis-2,3,5,6-tetrafluorophen-1-yl, di-methylcyclopentadienyl-Ti-bis-2,3,4 , 5,6-pentafluorophen-1-yl, bis (cyclopentadienyl) -bis (2,6-difluoro-3- (pyr-1-yl) phenyl) titanium, JP-A-1-304453, Examples thereof include iron-arene complexes described in JP-A-1-152109.

Examples of the hexaarylbisimidazole compound include JP-B-6-29285, U.S. Pat. Nos. 3,479,185, 4,311,783, 4,622,286, EP24629, Various compounds described in EP107792, US4410621, EP215453 and DE3211312 can be used. Preferable examples include 2,4,5,2 ′, 4 ′, 5′-hexaphenylbisimidazole, 2,2′-bis (o-methylphenyl) -4,4 ′, 5,5′- Tetraphenylbiimidazole, 2,2′-bis (2-chlorophenyl) -4,5,4 ′, 5′-tetraphenylbisimidazole, 2,2′-bis (2-bromophenyl) -4,5,4 ', 5'-tetraphenylbisimidazole, 2,2'-bis (2,4-dichlorophenyl) -4,5,4', 5'-tetraphenylbisimidazole, 2,2'-bis (2-chlorophenyl) -4,5,4 ', 5'-tetrakis (3-methoxyphenyl) -bisimidazole, 2,5,2', 5'-tetrakis (2-chlorophenyl) -4,4'-bis (3,4) Dimethoxyphenyl) bisimidazole, 2,2'-bi (2,6-dichlorophenyl) -4,5,4 ′, 5′-tetraphenylbisimidazole, 2,2′-bis (2-nitrophenyl) -4,5,4 ′, 5′-tetraphenylbis Imidazole, 2,2′-di-o-tolyl-4,5,4 ′, 5′-tetraphenylbisimidazole, 2,2′-bis (2-ethoxyphenyl) -4,5,4 ′, 5 ′ -Tetraphenylbisimidazole, 2,2'-bis (2,6-difluorophenyl) -4,5,4 ', 5'-tetraphenylbisimidazole, and 2,2'-bis (o-trifluorophenyl) Examples include -4,4 ', 5,5'-tetraphenylbiimidazole.
Two or more hexaarylbisimidazole compounds may be used in combination.

  Examples of the organoboron compound include JP-A-62-143044, JP-A-62-1050242, JP-A-9-188585, JP-A-9-188686, JP-A-9-188710, JP-A 2000-. No. 131837, Japanese Patent Application Laid-Open No. 2002-107916, Japanese Patent No. 2764769, Japanese Patent Application Laid-Open No. 2002-116539, and Kunz, Martin “Rad Tech '98. Proceeding April 19-22, 1998, Chicago”, etc. Organic borate salts described in JP-A-6-157623, JP-A-6-175564, JP-A-6-175561, and organic boron oxosulfonium complexes, JP-A-6-175554 Japanese Laid-Open Patent Publication No. 6-175553 Organoboron iodonium complexes described in Japanese Patent Laid-Open No. 9-188710, organoboron phosphonium complexes described in JP-A-9-188710, JP-A-6-348011, JP-A-7-128785, JP-A-7-140589, JP Examples thereof include organoboron transition metal coordination complexes such as 7-306527 and JP-A-7-292014.

  Examples of the disulfone compound include compounds described in JP-A Nos. 61-166544 and 2003-328465.

  Examples of the oxime ester compound include JCS Perkin II (1979) 1653-1660), JCSPerkin II (1979) 156-162, Journal of Photopolymer Science and Technology (1995) 202-232, and JP-A 2000-66385. And compounds described in JP 2000-80068 A. Specific examples include compounds represented by the following structural formula.

  Examples of the onium salt compound include S.I. I. Schlesinger, Photogr. Sci. Eng. , 18, 387 (1974), T.A. S. Diazonium salts described in Bal et al, Polymer, 21, 423 (1980), ammonium salts described in US Pat. No. 4,069,055, JP-A-4-365049, etc., US Pat. No. 4,069 , 055, 4,069,056, phosphonium salts described in European Patent Nos. 104,143, U.S. Pat. Nos. 339,049, 410,201,580, , 604,581 specification, J. V. Crivello et al, Macromolecules, 10 (6), 1307 (1977), J. MoI. V. Crivello et al, J.A. Polymer Sci. , Polymer Chem. Ed. , 17, 1047 (1979), a selenonium salt described in C.I. S. Wen et al, Teh, Proc. Conf. Rad. CuringASIA, p478 Tokyo, Oct (1988) and onium salts such as arsonium salts.

  In the present invention, these onium salts function not as acid generators but as ionic radical polymerization initiators.

  The onium salt suitably used in the present invention is an onium salt represented by the following general formulas (RI-I) to (RI-III).

In the formula (RI-I), Ar ₁₁ represents an aryl group having 20 or less carbon atoms which may have 1 to 6 substituents, and preferred substituents include an alkyl group having 1 to 12 carbon atoms and a carbon number. 1-12 alkenyl group, C1-C12 alkynyl group, C1-C12 aryl group, C1-C12 alkoxy group, C1-C12 aryloxy group, halogen atom, C1-C1 12 alkylamino groups, C1-C12 dialkylamino groups, C1-C12 alkylamide groups or arylamide groups, carbonyl groups, carboxyl groups, cyano groups, sulfonyl groups, C1-C12 thioalkyl groups And a thioaryl group having 1 to 12 carbon atoms. Z ₁₁ ^- represents a monovalent anion, specifically a halogen ion, a perchlorate ion, a hexafluorophosphate ion, a tetrafluoroborate ion, sulfonate ion, sulfinate ion, thiosulfonate ion, and sulfate ion. Among these, perchlorate ion, hexafluorophosphate ion, tetrafluoroborate ion, sulfonate ion and sulfinate ion are preferable from the viewpoint of stability.

In the formula (RI-II), Ar ₂₁ and Ar ₂₂ each independently represent an aryl group having 20 or less carbon atoms which may have 1 to 6 substituents, and preferred substituents include 1 to 1 carbon atoms. 12 alkyl groups, an alkenyl group having 1 to 12 carbon atoms, an alkynyl group having 1 to 12 carbon atoms, an aryl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryloxy group having 1 to 12 carbon atoms, Halogen atom, C1-C12 alkylamino group, C1-C12 dialkylamino group, C1-C12 alkylamide group or arylamide group, carbonyl group, carboxyl group, cyano group, sulfonyl group, carbon Examples thereof include a thioalkyl group having 1 to 12 carbon atoms and a thioaryl group having 1 to 12 carbon atoms. Z ₂₁ ^- represents a monovalent anion. Specific examples include halogen ions, perchlorate ions, hexafluorophosphate ions, tetrafluoroborate ions, sulfonate ions, sulfinate ions, thiosulfonate ions, and sulfate ions. Among these, perchlorate ion, hexafluorophosphate ion, tetrafluoroborate ion, sulfonate ion, sulfinate ion, and carboxylate ion are preferable from the viewpoint of stability and reactivity.

In the formula (RI-III), R ₃₁ , R ₃₂ and R ₃₃ are each independently an aryl group, alkyl group, alkenyl group or alkynyl having 20 or less carbon atoms, which may have 1 to 6 substituents. Represents a group. Among them, an aryl group is preferable from the viewpoint of reactivity and stability. Examples of the substituent include an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 1 to 12 carbon atoms, an alkynyl group having 1 to 12 carbon atoms, an aryl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, Aryloxy group having 1 to 12 carbon atoms, halogen atom, alkylamino group having 1 to 12 carbon atoms, dialkylamino group having 1 to 12 carbon atoms, alkylamide group or arylamide group having 1 to 12 carbon atoms, carbonyl group, carboxyl Group, a cyano group, a sulfonyl group, a thioalkyl group having 1 to 12 carbon atoms, and a thioaryl group having 1 to 12 carbon atoms. Z ₃₁ ^- represents a monovalent anion. Specific examples include halogen ions, perchlorate ions, hexafluorophosphate ions, tetrafluoroborate ions, sulfonate ions, sulfinate ions, thiosulfonate ions, and sulfate ions. Among these, perchlorate ion, hexafluorophosphate ion, tetrafluoroborate ion, sulfonate ion, sulfinate ion, and carboxylate ion are preferable from the viewpoints of stability and reactivity. More preferred are the carboxylate ions described in JP-A No. 2001-343742, and particularly preferred are the carboxylate ions described in JP-A No. 2002-148790.

  The radical polymerization initiator is not limited to the above, but particularly from the viewpoint of reactivity and stability, triazine initiators, organic halogen compounds, metallocene compounds, hexaarylbiimidazole compounds, organic boron compounds, oxime ester compounds, onium salts. Compounds are preferable, and triazine-based initiators, organic halogen compounds, metallocene compounds, hexaarylbiimidazole compounds, and onium salt compounds are more preferable.

  The photopolymerization initiator is preferably added in an amount of 0.1 to 50% by mass, more preferably 0.5 to 30% by mass, and particularly preferably 0.8 to 20% by mass with respect to the total solid content of the photosensitive layer. Can do.

  Photopolymerization initiators are optionally thiol compounds such as 2-mercaptobenzthiazole, 2-mercaptobenzimidazole, 2-mercaptobenzoxazole, amines such as N-phenylglycine, N, N-dialkylamino aromatic alkyl esters It is known that the photoinitiating ability can be further enhanced by using in combination with a hydrogen-donating compound such as a compound. A mercapto group-containing compound is particularly preferable as a hydrogen donating compound having a high photoinitiating ability and suitable for the present invention.

  A more preferred example is a sulfur-containing compound (mercapto group-containing heterocyclic compound) represented by the following general formula (2) or (3). In general formulas (2) and (3), the structures of tautomers are shown.

(In the formulas (2) and (3), R ₂ , R ₃ and R ₄ are each independently a hydrogen atom, a substituted or unsubstituted linear or branched alkyl group having 1 to 18 carbon atoms, substituted or unsubstituted Represents a substituted alicyclic alkyl group or aromatic group having 5 to 20 carbon atoms, and examples of the substituent include a halogen atom, a hydroxyl group, an amino group, a thiol group, an acetyl group, and a carboxyl group.

  Preferred specific examples (SH1) to (SH20) of the compound represented by the general formula (2) or (3) are shown below, but the present invention is not limited to these specific examples. The following structure is shown by the -SH group-containing structure of the tautomer.

  Specific example of general formula (2)

  Specific example of general formula (3)

  The mercapto group-containing heterocyclic compound is preferably used in a ratio of 0.2 to 10.0 mol, more preferably in a ratio of 0.5 to 6.0 mol, and still more preferably with respect to 1 mol of the hexaarylbisimidazole compound. Is a ratio of 0.5 to 4.0 mol.

[Addition polymerizable compound having an ethylenically unsaturated double bond]
The addition polymerizable compound having an ethylenically unsaturated double bond used in the present invention may be arbitrarily selected from compounds having at least one ethylenically unsaturated double bond group, preferably two or more. it can. For example, it has chemical forms such as monomers, prepolymers, that is, dimers, trimers and oligomers, copolymers thereof, and mixtures thereof. Examples of monomers include esters of unsaturated carboxylic acids (eg, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid, etc.) and aliphatic polyhydric alcohol compounds, unsaturated carboxylic acids and aliphatic Examples include amides with polyvalent amine compounds.

  Specific examples of the monomer of an ester of an aliphatic polyhydric alcohol compound and an unsaturated carboxylic acid include acrylic acid esters such as ethylene glycol diacrylate, triethylene glycol diacrylate, 1,3-butanediol diacrylate, and tetramethylene glycol. Diacrylate, propylene glycol diacrylate, neopentyl glycol diacrylate, trimethylolpropane triacrylate, trimethylolpropane tri (acryloyloxypropyl) ether, trimethylolethane triacrylate, hexanediol diacrylate, 1,4-cyclohexanediol diacrylate , Tetraethylene glycol diacrylate, pentaerythritol diacrylate, pentaerythritol triacrylate , Pentaerythritol tetraacrylate, dipentaerythritol diacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, sorbitol triacrylate, sorbitol tetraacrylate, sorbitol pentaacrylate, sorbitol hexaacrylate, tri (acryloyloxyethyl) isocyanurate, Examples include polyester acrylate oligomers.

  Methacrylic acid esters include tetramethylene glycol dimethacrylate, triethylene glycol dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate, ethylene glycol dimethacrylate, 1,3-butanediol dimethacrylate, Hexanediol dimethacrylate, pentaerythritol dimethacrylate, pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate, dipentaerythritol dimethacrylate, dipentaerythritol hexamethacrylate, dipentaerythritol pentamethacrylate, sorbitol trimethacrylate, sorbitol tetramethacrylate, bis [p (3-methacryloxy-2-hydroxypropoxy) phenyl] dimethyl methane, bis - [p- (methacryloxyethoxy) phenyl] dimethyl methane.

  Itaconic acid esters include ethylene glycol diitaconate, propylene glycol diitaconate, 1,3-butanediol diitaconate, 1,4-butanediol diitaconate, tetramethylene glycol diitaconate, pentaerythritol diitaconate And sorbitol tetritaconate.

Examples of crotonic acid esters include ethylene glycol dicrotonate, tetramethylene glycol dicrotonate, pentaerythritol dicrotonate, and sorbitol tetradicrotonate.
Examples of isocrotonic acid esters include ethylene glycol diisocrotonate, pentaerythritol diisocrotonate, and sorbitol tetraisocrotonate.

  Examples of maleic acid esters include ethylene glycol dimaleate, triethylene glycol dimaleate, pentaerythritol dimaleate, and sorbitol tetramaleate.

  Specific examples of amide monomers of aliphatic polyvalent amine compounds and unsaturated carboxylic acids include methylene bis-acrylamide, methylene bis-methacrylamide, 1,6-hexamethylene bis-acrylamide, 1,6-hexamethylene bis-methacrylic. Examples include amide, diethylenetriamine trisacrylamide, xylylene bisacrylamide, and xylylene bismethacrylamide.

Further, urethane acrylates as described in JP-A-51-37193, polyester acrylates as described in JP-A-48-64183, JP-B-49-43191, JP-B-52-30490 And polyfunctional acrylates and methacrylates such as epoxy acrylates obtained by reacting an epoxy resin with (meth) acrylic acid. Furthermore, Journal of Japan Adhesion Association Vol. 20, no. 7, 300-308 (1984). Photocurable monomers and oligomers can also be used.
Specifically, NK oligo U-4HA, U-4H, U-6HA, U-6ELH, U-108A, U-1084A, U-200AX, U-122A, U-340A, U-324A, UA-100 (Manufactured by Shin-Nakamura Chemical Co., Ltd.), UA-306H, AI-600, UA-101T, UA-101I, UA-306T, UA-306I (manufactured by Kyoeisha Yushi), Art Resin UN-9200A, UN-3320HA, UN-3320HB , UN-3320HC, SH-380G, SH-500, SH-9832 (manufactured by Negami Kogyo), PLEX 6661-O (manufactured by Degussa, Germany), and the like.
The amount of the addition polymerizable compound having an ethylenically unsaturated double bond is preferably in the range of 5 to 90% by mass, more preferably in the range of 20 to 75% by mass with respect to the total solid content of the photosensitive layer.

[Binder polymer]
The binder polymer of the present invention is a polymer compound (hereinafter, appropriately referred to as a specific polymer) having at least one structure represented by the general formula (I) in the side chain.
—L ₁ —X—NH—Y—R ₁ (I)
As the binder, a polymer compound selected from (meth) acrylic resin, styrene resin, vinyl acetal resin, urethane resin, urea resin, amide resin, ester resin, carbonate resin, and epoxy resin is preferable, and (meth) acrylic resin is more preferable. preferable. The specific polymer of the present invention can be produced by polymerizing a polymerization component having the above structure in the side chain.

  In the lithographic printing plate precursor according to the present invention, a polymer compound having a structure represented by the general formula (I) is used as a polymer compound that functions as a binder, and acidic hydrogen atoms in the specific structure are treated with an aqueous solution. In addition to exhibiting developability due to this, the hydrogen bondability of the acidic hydrogen atom imparts high film strength to the image recording layer, and therefore, it is considered that it effectively prevents a decrease in printing durability of the image area after processing. .

In the formula, L ₁ represents a single bond or a divalent linking group bonded to the polymer main chain.
Examples of the divalent linking group include an alkylene group, an arylene _{group, -CO -, - SO 2 -} , - O -, - S -, - NR 3 -, (R 3 is a hydrogen atom, an alkyl group or an aryl group, Or a linking group formed by a combination of two or more of these.

  Examples of the alkylene group include a divalent organic residue obtained by removing any one of the hydrogen atoms on the alkyl group having 1 to 20 carbon atoms, preferably having 1 to 12 carbon atoms. Examples thereof include straight chain, branched chain having 3 to 12 carbon atoms and cyclic alkylene group having 5 to 10 carbon atoms. The alkylene group may further have a substituent.

  Preferred examples of the substituent include an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, an alkynyl group having 7 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, and an alkoxy group having 1 to 12 carbon atoms. , Aryloxy group having 6 to 12 carbon atoms, halogen atom, alkylamide group or arylamide group having 1 to 12 carbon atoms, carbonyl group, cyano group, sulfonyl group, thioalkyl group having 1 to 12 carbon atoms, 6 to 12 carbon atoms Of thioaryl groups.

  Examples of the arylene group include those obtained by removing any one of the hydrogen atoms on the aryl group having 6 to 20 carbon atoms as a divalent organic residue, preferably phenylene and naphthylene groups. Can do. The arylene group may further have a substituent.

  The substituent that the arylene group may have is the same as the above-described substituent that the alkylene group may have.

L ₁ is a single bond, an alkylene group, an arylene group, —CO—, —SO ₂ —, —O—, —NR ₃ —, (R ₃ represents a hydrogen atom, an alkyl group, or an aryl group). Or it is preferable that it is a bivalent coupling group which consists of a combination of these two or more.

X and Y each independently represent a single bond or a divalent linking group. The divalent linking group represented by X and Y has the same meaning as that represented by L ₁ . Preferred is —CO— or —SO ₂ —. At least one of X and Y represents —SO ₂ —.

R ₁ represents a hydrogen atom or a monovalent organic group. Examples of the monovalent organic group represented by R ₁ include an alkyl group that may have a substituent, a cycloalkyl group that may have a substituent, an aryl group that may have a substituent, or Examples thereof include an aralkyl group which may have a substituent. Preferred are an alkyl group having 6 to 12 carbon atoms which may have a substituent, an aryl group having 6 to 10 carbon atoms which may have a substituent, and an aralkyl group having 7 to 12 carbon atoms. Here, the substituent is the same as the above-described substituent that the alkylene group may have.

  Among the specific polymers according to the present invention, the (meth) acrylic resin is a polymer of one or more radical polymerizable compounds having a group represented by the general formula (I) in the structure, or the general formula (I 1) one or more of radically polymerizable compounds having a group represented by the following formula in the structure and one or more of other radically polymerizable compounds having no such group as described above: In general, a known suspension polymerization method or solution polymerization method can be applied to the production of the polymer compound.

  The repeating unit derived from the radically polymerizable compound having a group represented by the general formula (I) in its structure is preferably 5 mol% to 90 mol%, more preferably, based on all repeating units of the specific polymer of the present invention. Is contained at 10 mol% to 80 mol%.

  Specific examples of the repeating unit having a group represented by the general formula (I) in the structure are shown below, but the present invention is not limited thereto.

  For the purpose of improving various performances such as image strength, the specific polymer of the present invention contains a radical polymerizable compound having no group as described above in addition to the radical polymerizable compound having the group as described above. Polymerization is also a preferred embodiment. Examples of such radical polymerizable compounds include acrylic acid esters, methacrylic acid esters, N, N-2 substituted acrylamides, N, N-2 substituted methacrylamides, styrenes, acrylonitriles, and methacrylonitrile. And radically polymerizable compounds selected from among the above.

  Specifically, for example, acrylic esters such as alkyl acrylate (the alkyl group preferably has 1 to 20 carbon atoms) (specifically, for example, methyl acrylate, ethyl acrylate, acrylic Propyl acrylate, butyl acrylate, amyl acrylate, ethyl hexyl acrylate, octyl acrylate, tert-octyl acrylate, chloroethyl acrylate, 2,2-dimethylhydroxypropyl acrylate, 5-hydroxypentyl acrylate, trimethylolpropane Monoacrylate, pentaerythritol monoacrylate, glycidyl acrylate, benzyl acrylate, methoxybenzyl acrylate, furfuryl acrylate, tetrahydrofurfuryl acrylate, etc.), aryl acrylate (for example, Such as E nil acrylate),

(Meth) acrylic acid ester having carbon or carbon unsaturated bond in the side chain substituent (for example, allyl acrylate, 2-allyloxyethyl acrylate, propargyl acrylate, allyl methacrylate, 2-allyloxyethyl methacrylate, propargyl methacrylate, etc.) Methacrylic esters such as alkyl methacrylate (the alkyl group preferably has 1 to 20 carbon atoms) (for example, methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, amyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, benzyl) Methacrylate, chlorobenzyl methacrylate, octyl methacrylate, 4-hydroxybutyl methacrylate, 5-hydroxypentyl methacrylate Acrylate, 2,2-dimethyl-3-hydroxypropyl methacrylate, trimethylolpropane monomethacrylate, pentaerythritol monomethacrylate, glycidyl methacrylate, furfuryl methacrylate, tetrahydrofurfuryl methacrylate, etc., aryl methacrylate (eg, phenyl methacrylate, cresyl methacrylate) , Naphthyl methacrylate, etc.), polymerizable compounds corresponding to the following repeating units,

Styrenes such as styrene and alkyl styrene (for example, methyl styrene, dimethyl styrene, trimethyl styrene, ethyl styrene, diethyl styrene, isopropyl styrene, butyl styrene, hexyl styrene, cyclohexyl styrene, decyl styrene, benzyl styrene, chloromethyl styrene) , Trifluoromethyl styrene, ethoxymethyl styrene, acetoxymethyl styrene, etc.), alkoxy styrene (eg methoxy styrene, 4-methoxy-3-methyl styrene, dimethoxy styrene etc.), halogen styrene (eg chloro styrene, dichloro styrene, trichloro styrene) , Tetrachlorostyrene, pentachlorostyrene, bromostyrene, dibromostyrene, iodostyrene, fluorostyrene, trifluoro Styrene, 2-bromo-4-trifluoromethyl styrene, 4-fluoro-3-trifluoromethyl styrene etc.), acrylonitrile, methacrylonitrile, and the like.

  The specific polymer of the present invention may further have a repeating unit represented by the following formula (1) (hereinafter also referred to as repeating unit (1)).

In formula (1), X represents an oxygen atom, a sulfur atom or a —NH— group, Y represents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an alicyclic alkyl group having 5 to 12 carbon atoms, or 6 carbon atoms. To a group having 20 aromatic rings. Z represents an oxygen atom, a sulfur atom or a —NH— group, R ₁ represents an alkyl group having 1 to 18 carbon atoms, an alkyl group having an alicyclic structure having 5 to 20 carbon atoms or an aromatic ring having 6 to 20 carbon atoms. Represents a group having
Specific examples of the repeating unit (1) include the structures shown in the following (1-1) to (1-9), but the present invention is not limited thereto.

  When the total number of repeating units is 100, the content of the repeating unit (1) is 1 to 40, preferably 3 to 25, more preferably 5 to 15 of them.

  Among these radically polymerizable compounds, acrylic esters, methacrylic esters, (meth) acrylic esters having a carbon-carbon unsaturated bond in the side chain substituent, and styrenes are preferably used. is there. These may be used alone or in combination of two or more. The content of these copolymerization components used is preferably 95 mol% or less, particularly preferably 20 to 90 mol%.

  In order to improve various performances such as non-image area removability, the specific polymer according to the present invention may be copolymerized with a radical polymerizable compound having an acid group. Examples of such an acid group having radical polymerizability include a carboxylic acid, a sulfonic acid, and a phosphoric acid group, and a particularly preferable one is a carboxylic acid. Examples of the radical polymerizable compound containing a carboxylic acid include acrylic acid, methacrylic acid, itaconic acid, crotonic acid, incrotonic acid, maleic acid, p-carboxyl styrene, and particularly preferred are acrylic acid, methacrylic acid, and the like. Acid, p-carboxylstyrene. These may be used alone or in combination of one or more. The content of these copolymerization components used is preferably 50 mol% or less, and particularly preferably 20 mol% or less.

  The specific polymer according to the present invention may be a homopolymer, but two or more kinds of copolymers having different radical polymerizable compounds having a group represented by the general formula (I), or a general formula (I ) Is a copolymer of one or more radically polymerizable compounds having a group represented by formula (1) and one or more of the other radically polymerizable compounds described above, the constitution of the copolymer includes a block copolymer, Any of a random copolymer and a graft copolymer may be used.

  Examples of the solvent used for synthesizing such a polymer compound include ethylene dichloride, cyclohexanone, methyl ethyl ketone, acetone, methanol, ethanol, propanol, butanol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, 2-methoxy. Examples include ethyl acetate, 1-methoxy-2-propanol, 1-methoxy-2-propyl acetate, N, N-dimethylformamide, N, N-dimethylacetamide, dimethyl sulfoxide, toluene, ethyl acetate, methyl lactate, and ethyl lactate. It is done. These solvents may be used alone or in combination of two or more.

  The polymer compound of the present invention has a weight average molecular weight of preferably 2,000 or more, more preferably 5,000 to 300,000. The specific polymer according to the present invention may contain an unreacted monomer. In this case, the proportion of the monomer in the polymer compound is desirably 15% by weight or less.

  The polymer compound according to the present invention may be used alone or in combination of two or more. Moreover, you may mix and use the other high molecular compound which does not have group represented by general formula (I). In this case, the polymer compound having no group represented by the general formula (I) is 50% by weight or less, more preferably 30% by weight or less in the polymer compound. The content of the specific polymer contained in the image recording material of the present invention is about 5 to 95% by weight, preferably about 10 to 85% by weight in terms of solid content.

  Specific examples of the specific polymer (meth) acrylic resin of the present invention include (PP-1) to (PP-11) shown in Table 1 below, but the present invention is not limited thereto. .

  In order to maintain the developability of the photosensitive layer, the specific polymer of the present invention preferably has an appropriate molecular weight, and the mass average molecular weight is preferably 5,000 to 300,000. A more preferable range is 20000 to 150,000.

  The specific polymer of the present invention can be contained in an arbitrary amount in the photosensitive layer, but when it exceeds 90% by mass, it may not give a preferable result in terms of image strength to be formed. , Preferably 10 to 90 mass%, more preferably 30 to 80 mass%.

  In the photosensitive layer used in the present invention, in addition to the above basic components, other components can be contained as required. For example, it may contain a dye or pigment capable of absorbing light having a laser emission wavelength of ± 50 nm used for image exposure. However, these dyes or pigments, unlike sensitizing dyes, do not have a function of transmitting energy to the photopolymerization initiator.

  The dye or pigment is not particularly limited as long as it is a dye or pigment capable of absorbing light having a wavelength of laser emission wavelength ± 50 nm, but is preferably a dye or pigment having an absorption maximum between laser emission wavelengths ± 50 nm, more preferably A dye or pigment having an absorption maximum between laser emission wavelengths ± 20 nm is preferable, and a dye or pigment having an absorption maximum at the same wavelength as the laser emission wavelength is more preferable.

  In the present invention, exposure with a laser in the blue or ultraviolet region emitting light of 350 to 450 nm is particularly desirable, and a yellow dye or pigment is desirable as a dye or pigment corresponding to this laser.

  Examples of yellow dyes include yellow acid dyes. Specific examples include a group of acid dyes and C.I. Acid Yellow listed in the Handbook of Dyes. Particularly effective dyes include C.I. Acid Yellow 17, C.I. Acid Yellow 19, C.I. Acid Yellow 23, C.I. Acid Yellow 38, C.I. Acid Yellow 42, C.I. Acid Yellow 61, C.I. Acid Yellow 72, C.I.

  The following dyes are also preferably used.

  Examples of yellow pigments include Novoperm Yellow H2G, Seikafast Yellow 2200, Seikafast Yellow 2300, Seikafast Yellow, HOSTACOPY Y501, Yellow Masterbatch, PV Fast Yellow HG, Novoperm Yellow P-HG, Novoperm Yellow M2R, and the like.

  By using such a dye or pigment, the effect of suppressing clogging of the shadow portion due to the influence of the reflected light or scattered light of the laser appears, and high-definition AM screen printing or FM screen printing, especially FM screen is used. Thus, it is possible to provide a printing plate that gives a good printed matter with no halftone unevenness even during exposure.

  The amount of the dye or pigment added to the photosensitive layer is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, based on the mass of the photosensitive layer. Further, from the viewpoint of keeping the amount of light reaching the photosensitive layer and keeping the sensitivity in a good range, the addition amount is preferably 10% by mass or less, and more preferably 5% by mass or less.

  Further, in the photosensitive layer used in the present invention, addition polymerization having an ethylenically unsaturated double bond during the production or storage of the composition for forming the photosensitive layer (photopolymerization type photosensitive composition). In order to prevent unnecessary thermal polymerization of the compound, it is desirable to add a small amount of a thermal polymerization inhibitor. 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-t-butylphenol), N-nitrosophenylhydroxylamine cerium salt, N-nitrosophenylhydroxylamine aluminum salt and the like. The addition amount of the thermal polymerization inhibitor is preferably about 0.01% by mass to about 5% by mass of the total components of the composition. If necessary, in order to prevent polymerization inhibition by oxygen, higher fatty acid derivatives such as behenic acid and behenic acid amide may be added and unevenly distributed on the surface of the photosensitive layer in the drying process after coating. Good. The addition amount of the higher fatty acid derivative is preferably about 0.5% by mass to about 10% by mass of the total components of the photopolymerization type photosensitive composition.

A colorant may be added for the purpose of coloring the photosensitive layer. Examples of the colorant include phthalocyanine pigments (CI Pigment Blue 15: 3, 15: 4, 15: 6, etc.), azo pigments, pigments such as carbon black and titanium oxide, ethyl violet, crystal violet, There are azo dyes, anthraquinone dyes, and cyanine dyes. The addition amount of the colorant is preferably about 0.5% by mass to about 5% by mass of the total components of the photopolymerization type photosensitive composition.
In order to improve the physical properties of the cured film, additives such as inorganic fillers and plasticizers such as dioctyl phthalate, dimethyl phthalate and tricresyl phosphate may be added. The addition amount of these additives is preferably 10% by mass or less based on the total components of the photopolymerization type photosensitive composition.
A surfactant can be added to the composition for forming the photosensitive layer in order to improve the coating surface quality. Suitable surfactants include, for example, fluorine-based nonionic surfactants.

In the present invention, the photosensitive layer composition is coated on a support that will be described in detail later to form a photosensitive layer. When the composition for photosensitive layer is coated on the support, it is dissolved in an organic solvent to prepare a coating solution. Solvents that can be used include 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, di Tylene 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, lactic acid There are ethyl and the like. These solvents can be used alone or in combination. The solid content concentration in the coating solution is suitably 1 to 50% by mass.
The coverage of the photosensitive layer in the lithographic printing plate precursor of the present invention may range from about 0.1 g / m ² ~ about 10 g / m ² are preferred in mass after application and drying, and more preferably 0.3 to 5 g / m ² And more preferably 0.5 to 3 g / m ² .

[Protective layer]
An oxygen-blocking protective layer (overcoat layer) is preferably provided on the photosensitive layer in order to prevent an oxygen polymerization inhibiting action.
The coating amount of the protective layer is preferably in a range of 0.5 to 3.0 g / m ^2. If it is less than 0.5 g / m ² , the sensitivity may decrease, and if it exceeds 3.0 g / m ² , the burden on the treatment process may increase. Preferably, it is the range of 0.7-2.5 g / m < ² >.

The protective layer preferably contains a water-soluble polymer. Specifically, for example, polyvinyl alcohol, and its partial esters, ethers and acetals, or a substantial amount of water that makes them necessary water-soluble. Examples include copolymers containing substituted vinyl alcohol units. As the polyvinyl alcohol, those having a hydrolysis degree of 71 to 100% and a polymerization degree of 300 to 2400 are preferable. Specifically, Kuraray Co., Ltd. PVA-105, PVA-110, PVA-117, PVA-117H, PVA-120, PVA-124, PVA-124H, PVA-CS, PVA-CST, PVA-HC, PVA- 203, PVA-204, PVA-205, PVA-210, PVA-217, PVA-220, PVA-224, PVA-217EE, PVA-217E, PVA-220E, PVA-224E, PVA-405, PVA-420, PVA-613, L-8, etc. are mentioned. Moreover, polyvinyl acetate chloroacetate or propionate having a degree of hydrolysis of 88 to less than 100%, polyvinyl formal, polyvinyl acetal and the like can be mentioned. Other useful water-soluble polymers include polyvinyl pyrrolidone, gelatin and gum arabic, and the water-soluble polymers may be used alone or in combination.
In the present invention, in order to obtain particularly favorable results, it is desirable to use a polyvinyl alcohol having a hydrolysis degree of 95% or more.

Modified polyvinyl alcohol can also be used for the protective layer. In particular, acid-modified polyvinyl alcohol is preferably used.
(Acid-modified polyvinyl alcohol)
The acid-modified polyvinyl alcohol is not particularly limited as long as it is a vinyl alcohol polymer containing an appropriate amount of acid groups. In particular, a vinyl alcohol polymer containing an appropriate amount of a sulfonic acid group or a carboxyl group is preferably used. The former is called sulfonic acid-modified polyvinyl alcohol and the latter is called carboxylic acid-modified polyvinyl alcohol.
The acid-modified polyvinyl alcohol is preferably synthesized by polymerizing a monomer having an acid group together with vinyl acetate and then saponifying a part or all of the vinyl acetate to form vinyl alcohol. It is also possible to synthesize by combining a compound having an acid group.

  Examples of the monomer having a sulfonic acid group include ethylene sulfonic acid, allyl sulfonic acid, methallyl sulfonic acid, 2-acrylamido-2-methylpropane sulfonic acid, and salts thereof. Examples of the compound having a sulfonic acid group include aldehyde derivatives having a sulfonic acid group such as P-sulfonic acid benzaldehyde and salts thereof, and introduction by a conventionally known acetalization reaction is possible.

Examples of the monomer having a carboxyl group include fumaric acid, maleic acid, itaconic acid, maleic anhydride, phthalic anhydride, trimetic anhydride, acrylic acid and salts thereof, and acrylic acid esters such as methyl acrylate, methacrylic acid, and the like. And methacrylic acid esters such as methyl acid. Examples of the compound having a carboxyl group include monomers such as acrylic acid, which can be introduced by a conventionally known Michael addition reaction.
The acid-modified polyvinyl alcohol may be appropriately synthesized or may be a commercially available product.
Acid-modified polyvinyl alcohol can suppress a decrease in development removability of the photosensitive layer. Especially, a thing with a saponification degree of 91 mol% or more is preferable.
Specific examples of such highly saponified acid-modified polyvinyl alcohol include, for example, KL-118 manufactured by Kuraray Co., Ltd. (saponification degree: 97 mol%, average polymerization degree: 1800), KM-618. (Saponification degree 94 mol%, average polymerization degree 1800), KM-118 (saponification degree 97 mol%, average polymerization degree 1800), KM-106 (saponification degree 98.5 mol%, average polymerization degree 600), GOHSENAL T-330H (degree of saponification 99 mol%, average degree of polymerization 1700), GOHSENAL T-330 (degree of saponification 96.5 mol%, average degree of polymerization 1700), GOHSENAL T-, manufactured by Nippon Synthetic Chemical Industry Co., Ltd. 350 (degree of saponification 94 mol%, average degree of polymerization 1700), GOHSENAL T-230 (degree of saponification 96.5 mol%, average degree of polymerization 1500), go NARL T-215 (saponification degree 96.5 mol%, average degree of polymerization 1300), GOHSENAL T-HS-1 (saponification degree 99 mol%, average degree of polymerization 1300), manufactured by Nippon Vinegar Poval Co., Ltd. AF-17 (degree of saponification 96.5 mol%, average degree of polymerization 1700), AT-17 (degree of saponification 93.5 mol%, average degree of polymerization 1700) are mentioned.
Examples of the sulfonic acid-modified polyvinyl alcohol include SK-5102 (saponification degree: 98 mol%, average polymerization degree: 200) manufactured by Kuraray Co., Ltd., and Goseiran CKS-50 (saponification manufactured by Nippon Synthetic Chemical Industry Co., Ltd.). Degree 99 mol%, average degree of polymerization 300).

  In addition, it is particularly preferable to use acid-modified polyvinyl alcohol having an average degree of polymerization of vinyl alcohol units of 100 to 800 from the viewpoint of more effectively suppressing a decrease in development removability of the photosensitive layer. By using such an acid-modified polyvinyl alcohol having a low polymerization degree and a high saponification degree, it is possible to effectively suppress a decrease in the development removability of the photosensitive layer while maintaining an excellent oxygen barrier property. A protective layer can be obtained.

Examples of the acid-modified polyvinyl alcohol having a low polymerization degree and a high saponification degree as described above include itaconic acid and maleic acid having a saponification degree of 91 mol% or more and an average polymerization degree of vinyl alcohol units of 100 to 800. Carboxy-modified polyvinyl alcohol modified with an acid and sulfonic acid-modified polyvinyl alcohol are preferred.
The degree of modification of acid-modified polyvinyl alcohol represents the molar ratio of units having an acid group contained in the copolymer of acid-modified polyvinyl alcohol. The degree of modification of the acid-modified polyvinyl alcohol is preferably from 0.1 to 20 mol%, more preferably from 0.2 to 5 mol%.

As a solvent used in preparing the protective layer coating solution, pure water is preferable, but alcohols such as methanol and ethanol, and ketones such as acetone and methyl ethyl ketone may be mixed with pure water. The concentration of the solid content in the coating solution is suitably 1 to 20% by mass. In the protective layer, known additives such as a surfactant for improving the coating property and a water-soluble plasticizer for improving the physical properties of the film may be added. Examples of the water-soluble plasticizer include propionamide, cyclohexanediol, glycerin, sorbitol and the like. A water-soluble (meth) acrylic polymer may be added. The coverage of the protective layer is preferably in a range of from about 0.1 g / m ² ~ about 15 g / m ² by mass after drying, more preferably from 1.0 g / m ² ~ about 5.0 g / m ^2.

[Preparation method of lithographic printing plate]
Next, a method for preparing a lithographic printing plate using the lithographic printing plate precursor according to the invention will be described in detail. The method for producing a lithographic printing plate of the present invention comprises subjecting a lithographic printing plate precursor to image exposure (exposure step), and then adding a water-soluble polymer compound and / or carbonate ion and hydrogen carbonate ion, preferably carbonate ion and hydrogen carbonate ion, and / or Alternatively, the treatment (development step) is performed with an aqueous solution containing a surfactant. If necessary, a step of exposing and / or heating the lithographic printing plate precursor between the exposure step and the development step and / or after the development step may be provided.

  Image exposure of a lithographic printing plate precursor is performed by a method of exposing through a transparent original image having a line image, a halftone dot image or the like, a method of laser beam scanning with digital data, or the like. A desirable wavelength of the exposure light source is 350 nm to 450 nm or 760 nm to 1200 nm.

As an available laser light source that emits light of 350 nm to 450 nm, the following can be used. As a gas laser, an Ar ion laser (364 nm, 351 nm, 10 mW to 1 W), a Kr ion laser (356 nm, 351 nm, 10 mW to 1 W), a He-Cd laser (441 nm, 325 nm, 1 mW to 100 mW), and a solid laser as Nd: YAG (YVO ₄ ) and SHG crystal × 2 combinations (355 nm, 5 mW to 1 W), Cr: LiSAF and SHG crystal combination (430 nm, 10 mW), semiconductor laser system, KNbO ₃ ring resonator (430 nm, 30 mW), Combination of waveguide type wavelength conversion element and AlGaAs / InGaAs semiconductor (380 nm to 450 nm, 5 mW to 100 mW), combination of waveguide type wavelength conversion element, AlGaInP and AlGaAs semiconductor (300 nm to 350 nm, 5 mW to 100) W), AlGaInN (350nm~450nm, 5mW~30mW ), other, _{N 2} laser (337 nm as a pulse laser, pulse: 0.1 to 10), XeF (351 nm, pulse 10 to 250 mJ). Among these, an AlGaInN semiconductor laser (commercially available InGaN-based semiconductor laser 400 to 410 nm, 5 to 30 mW) is preferable in terms of wavelength characteristics and cost.

In addition, examples of usable lasers include infrared lasers. Although an infrared laser is not specifically limited, The solid laser and semiconductor laser which radiate | emit infrared rays with a wavelength of 760-1200 nm are mentioned suitably. The output of the infrared laser is preferably 100 mW or more. In order to shorten the exposure time, it is preferable to use a multi-beam laser device.
The exposure time per pixel is preferably within 20 μsec. Moreover, it is preferable that irradiation energy amount is 10-300 mJ / cm < ² >.

  Regarding the lithographic printing plate precursor exposure apparatus of the scanning exposure method, the exposure mechanism may be any of an inner drum method, an outer drum method, and a flat bed method, and a light source that can oscillate continuously is preferably used. .

  Other exposure light sources that can be used in the present invention include ultra high pressure, high pressure, medium pressure, and low pressure mercury lamps, chemical lamps, carbon arc lamps, xenon lamps, metal halide lamps, various visible and ultraviolet laser lamps, fluorescent lamps. A lamp, a tungsten lamp, sunlight, etc. are also mentioned.

  Next, the development process will be described in detail. In a normal processing step, the protective layer is removed by the pre-water washing step, then alkali development is performed, the alkali is removed by the post-water washing step, the gum treatment is performed in the gumming step, and the drying step is performed. In the present invention, development can be performed with a single solution. Preferably, by using an aqueous solution containing carbonate ions and hydrogen carbonate ions, the development process (processing with an aqueous solution) is performed in a single solution, and then the drying step can be performed. More preferably, development and gumming can be performed simultaneously by using an aqueous solution containing a water-soluble polymer compound and / or a surfactant in addition to carbonate ions and hydrogen carbonate ions. Guming is to hydrophilize the plate surface by using a water-soluble polymer compound and / or a surfactant. Therefore, a post-water washing step is not particularly required, and after performing development and gumming with one solution, a drying step can be performed. Further, since the protective layer can be removed simultaneously with development and gumming, no pre-water washing step is required. After development and gumming, it is preferable to dry after removing excess processing liquid using a squeeze roller or the like.

  The development process can be preferably carried out by an automatic processor equipped with a rubbing member. Examples of the automatic processor include an automatic processor described in JP-A-2-220061 and JP-A-60-59351, which performs a rubbing process while conveying a lithographic printing plate precursor after image exposure, or on a cylinder. Examples include an automatic processor described in US Pat. Nos. 5,148,746, 5,568,768 and British Patent 2,297,719, which rub the set lithographic printing plate precursor after image exposure while rotating a cylinder. Among these, an automatic processor using a rotating brush roll as the rubbing member is particularly preferable.

The rotating brush roll used in the present invention can be appropriately selected in consideration of the difficulty of scratching the image area and the stiffness 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, a metal or plastic groove mold material in which brush materials are implanted in a row, such as those described in JP-A-58-159533 and JP-A-3-100554, and JP-B-62-167253 A brush roll can be used in which the core is radially wound around a plastic or metal roll with no gap.
Examples of brush materials include plastic fibers (for example, polyesters such as polyethylene terephthalate and polybutylene terephthalate, polyamides such as nylon 6.6 and nylon 6.10, polyacrylics such as polyacrylonitrile and poly (meth) acrylate). , Polyolefin synthetic fibers such as polypropylene and polystyrene). For example, fibers having a hair diameter of 20 to 400 μm and a hair length of 5 to 30 mm can be preferably used.
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. It is preferable to use a plurality of rotating brush rolls.

  The rotating direction of the rotating brush roll may be the same or opposite to the conveying direction of the lithographic 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. 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 development step. Drying is performed by hot air, infrared rays, far infrared rays, or the like.

An example of the structure of an automatic processor suitably used in the method for producing a lithographic printing plate of the present invention is schematically shown in FIG. The automatic processor shown in FIG. 1 basically includes a developing unit 6 and a drying unit 10, and the lithographic printing plate precursor 4 is developed and gummed in the developing tank 20 and dried in the drying unit 10. More specifically, the automatic developing apparatus includes a developing unit 6 that develops a planographic printing plate precursor (hereinafter referred to as “PS plate”) 4 and a drying unit 10 that dries the developed PS plate 4. . An insertion port is formed in the side plate of the automatic developing device (the left portion in FIG. 1), and the PS plate 4 inserted from the insertion port is developed by a carry-in roller 16 provided on the inner surface of the side plate of the automatic developing device. It is conveyed to 6. In the developing tank 20 of the developing unit 6, a conveyance roller 22, a brush roller 24, and a squeeze roller 26 are sequentially provided from the upstream side in the conveyance direction, and a backup roller 28 is provided at an appropriate position therebetween. The PS plate 4 is immersed in the developing solution while being transported by the transport roller 22, and the brush roller 24 is rotated to remove the non-image portion of the PS plate 4 and be developed. The developed PS plate 4 is conveyed to the next drying unit 10 by a squeeze roller (unloading roller) 26.
The drying unit 10 is provided with a guide roller 36 and a pair of skewer rollers 38 in order from the upstream side in the transport direction. The drying unit 10 is provided with drying means such as hot air supply means and heat generation means (not shown). The drying unit 10 is provided with a discharge port. The PS plate 4 dried by the drying means is discharged into the discharge port 40, and the automatic developing process for the PS plate is completed.

A processing solution (hereinafter also referred to as a developing solution) used in the developing process is an aqueous solution containing carbonate ions and hydrogen carbonate ions. Preferably, the treatment liquid further contains a water-soluble polymer compound. Due to the presence of carbonate ions and hydrogen carbonate ions, a buffering effect is exerted, and even when the developer is used for a long period of time, fluctuations in pH can be suppressed, and development deterioration due to pH fluctuations, development residue generation, and the like can be suppressed. In order to allow carbonate ions and hydrogen carbonate ions to be present in the developer, carbonate and bicarbonate may be added to the developer, or by adjusting the pH after adding carbonate or bicarbonate, Ions and bicarbonate 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.
The pH of the developer is not particularly limited as long as it has a buffering effect, but is preferably in the range of pH 8.5 to 10.8. If it is less than 8.5, the developability of the non-image area is lowered, and if it is more than 10.8, the processing capacity is lowered due to the influence of carbon dioxide in the air.

  1-20 mass% is preferable with respect to the mass of alkaline aqueous solution, and, as for the total amount of carbonate and hydrogencarbonate, 3-15 mass% is more preferable, and 4-12 mass% is especially preferable. When the total amount is 1% by mass or more, developability and processing capacity are not deteriorated, and when it is 20% by mass or less, it is difficult to form precipitates and crystals, and further gelation occurs during neutralization during processing of the waste liquid of the developer. It becomes difficult 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, another 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.

  Examples of the water-soluble polymer compound used in the present invention include soybean polysaccharides, modified starches, gum arabic, dextrin, fiber derivatives (for example, carboxymethylcellulose, carboxyethylcellulose, methylcellulose, etc.) and modified products thereof, pullulan, polyvinyl alcohol and the like. Derivatives, polyvinylpyrrolidone, polyacrylamide and acrylamide copolymers, vinyl methyl ether / maleic anhydride copolymers, vinyl acetate / maleic anhydride copolymers, styrene / maleic anhydride copolymers, and the like. A preferable acid value of the water-soluble polymer compound is 0 to 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 mass aqueous solution is in the range of 10 to 100 mPa / sec.

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

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

Particularly preferable among the water-soluble polymer compounds include soybean polysaccharide, modified starch, gum arabic, dextrin, carboxymethylcellulose, polyvinyl alcohol and the like.
Two or more water-soluble polymer compounds can be used in combination. The content of the water-soluble polymer compound in the treatment liquid is preferably 0.1 to 20% by mass, more preferably 0.5 to 10% by mass.

The treatment liquid may contain a surfactant (anionic surfactant, nonionic surfactant, cationic surfactant, amphoteric surfactant, etc.).
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 Examples thereof include partial saponification products of maleic acid copolymer, partial saponification products of olefin-maleic anhydride copolymer, and naphthalene sulfonate formalin condensates. 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 adduct, alkylphenol ethylene oxide adduct, fatty acid ethylene oxide adduct, polyhydric alcohol fatty acid ester ethylene oxide adduct, higher alkylamine ethylene oxide adduct, fatty acid. Amidoethylene oxide adducts, fat and oil ethylene oxide adducts, polypropylene glycol ethylene oxide adducts, dimethylsiloxane-ethylene oxide block copolymers, dimethylsiloxane- (propylene oxide-ethylene oxide) block copolymers, and polyhydric alcohol type glycerol Fatty acid ester, fatty acid ester of pentaerythritol, fatty acid ester of sorbitol and sorbitan Fatty acid esters of sucrose, alkyl ethers of polyhydric alcohols, fatty acid amides of alkanolamines.

  The amphoteric surfactant used in the present invention is not particularly limited, and conventionally known amphoteric surfactants can be used. Examples thereof include carboxybetaines, aminocarboxylic acids, sulfobetaines, aminosulfuric esters, and imidazolines.

  Of the above surfactants, the term “polyoxyethylene” can be read as “polyoxyalkylene” such as polyoxymethylene, polyoxypropylene, polyoxybutylene, etc. These surfactants can also be used.

  Among these, surfactants used in the developer of the present invention include sorbitol and / or sorbitan fatty acid ester ethylene oxide adduct, polypropylene glycol ethylene oxide adduct, dimethylsiloxane-ethylene oxide block copolymer, dimethylsiloxane- (propylene). Oxide-ethylene oxide block copolymer, fatty acid ester of polyhydric alcohol, N-octyldimethylbetaine, N-lauryldimethylbetaine (Pionine C157K, Takemoto Yushi Co., Ltd.) Polyoxyethylene lauryl amino ether (Pionine, Takemoto Yushi Co., Ltd.) Carboxybetaines such as D3110), sodium salt of dioctylsulfosuccinic acid, polyoxyethylene naphthyl ether sulfate ester (manufactured by Nippon Emulsifier Co., Ltd.) Call B4SN), sodium alkyl naphthalene sulfonate (manufactured by Kao Corp. PELEX NB-L), a surfactant of the sulfonic acid and sulfuric acid anionic such as sodium dodecyl benzene sulfonic acid.

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. Further, acetylene glycol-based and acetylene alcohol-based oxyethylene adducts, fluorine-based and silicon-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 mass, more preferably from 0.01 to 5% by mass.

  In addition to the above, the treatment liquid of the present invention may contain a wetting agent, preservative, chelate compound, antifoaming agent, organic acid, 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. Generally, the wetting agent is used in an amount of 0.1 to 5% by weight based on the total weight of the treatment liquid.

  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-1,3diol, 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 exhibits a stable effect on bacteria, fungi, yeast, and the like, and varies depending on the type of bacteria, fungi, yeast, etc., but is 0.01-4 for the treatment liquid. A range of mass% 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 and phosphonoalkanetricarboxylic acids. Organic amine salts are also effective in place of the sodium and potassium salts of the chelating agents. A chelating agent is selected that is stably present in the treatment liquid composition and does not impair the printability. The addition amount is preferably 0.001 to 1.0% by mass with respect to the treatment liquid.

  As the antifoaming agent, a general silicon-based self-emulsifying type, emulsifying type, nonionic HLB 5 or less compound can be used. Silicon antifoaming agents are preferred. Among them, emulsification dispersion type and solubilization can be used. The content of the antifoaming agent is preferably in the range of 0.001 to 1.0% by mass with respect to the treatment liquid.

  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. . The organic acid can also be used in the form of its alkali metal salt or ammonium salt. The content of the organic acid is preferably 0.01 to 0.5% by mass with respect to the treatment liquid.

  Examples of the organic solvent include aliphatic hydrocarbons (hexane, heptane, “Isopar E, H, G” (produced by Esso Chemical Co., Ltd.) or gasoline, kerosene, etc.), aromatic hydrocarbons (toluene, xylene, etc.) ) Or halogenated hydrocarbons (methylene dichloride, ethylene dichloride, trichrene, 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 mass from the viewpoint 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 mass based on the total mass of the treatment liquid.

  The development temperature is usually 60 ° C. or lower, preferably about 15 to 40 ° C. In the developing process using an automatic developing machine, the developing solution may be fatigued depending on the amount of processing, and thus the processing capability may be restored by using a replenishing solution or a fresh developing solution.

  In the method for preparing a lithographic printing plate according to the present invention, the entire surface may be heated between exposure and development, if necessary. By such heating, an image forming reaction in the image recording layer is promoted, and advantages such as improvement in sensitivity and printing durability and stabilization of sensitivity may occur.

The heating 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 carried out by holding the plate surface temperature in the range of 70 to 150 ° C. for 1 second to 5 minutes. Preferably, the temperature is 80 ° C to 140 ° C for 5 to 1 minute, more preferably 90 ° C to 130 ° C for 10 to 30 seconds. This range is preferable in that the above effect can be obtained efficiently and there is no adverse effect such as deformation of the printing plate due to heat.
The heat treatment means used for the heat treatment is preferably connected to the plate setter used in the exposure process and the developing device used in the development process so as to be automatically continuously processed. 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 to be used 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.
Further, the entire surface of the printing plate after development 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. In order to obtain sufficient printing durability, the exposure dose is preferably at least 10 mJ / cm ² or more, 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 ° C to 150 ° C, more preferably 35 ° C to 130 ° C, and still more preferably 40 ° C to 120 ° C. Specifically, the method described in JP 2000-89478 A can be used.
Further, for the purpose of improving printing durability, the developed printing plate can be heated under very strong conditions. The heating temperature is usually in the range of 200 to 500 ° C. If the temperature is low, sufficient image strengthening action cannot be obtained, and if it is too high, problems such as deterioration of the support and thermal decomposition of the image area may occur.
The lithographic printing plate thus obtained is loaded on an offset printing machine and used for printing a large number of sheets.

EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these.
<Examples 1-28 and Comparative Examples 1-2>
[Production of support]
The following surface treatment was performed using an aluminum plate (JIS A1050) having a thickness of 0.03 mm.
(A) Mechanical surface roughening treatment While supplying a suspension of a polishing agent (pumice) having a specific gravity of 1.12 and water as a polishing slurry liquid to the surface of the aluminum plate, mechanical roughening is performed by a rotating nylon brush. Surface treatment was performed. The average particle size of the abrasive was 30 μm, and the maximum particle size was 100 μm. The material of the nylon brush was 6 · 10 nylon, the hair length was 45 mm, and the hair diameter was 0.3 mm. The nylon brush was planted so as to be dense by making a hole in a stainless steel tube having a diameter of 300 mm. Three rotating brushes were used. The distance between the two support rollers (φ200 mm) at the bottom of the brush was 300 mm. The brush roller was pressed until the load of the drive motor for rotating the brush became 7 kW plus with respect to the load before the brush roller was pressed against the aluminum plate. The rotating direction of the brush was the same as the moving direction of the aluminum plate. The rotation speed of the brush was 200 rpm.

(B) Alkaline etching treatment The aluminum plate was subjected to an etching treatment by spraying using an aqueous solution having a caustic soda concentration of 2.6 mass%, an aluminum ion concentration of 6.5 mass%, and a temperature of 70 ° C., thereby dissolving the aluminum plate by 10 g / m ² . . Then, water washing by spraying was performed.

(C) Desmutting treatment The desmutting treatment was performed by spraying with a 1% by mass aqueous solution of nitric acid at a temperature of 30 ° C. (containing 0.5% by mass of aluminum ions), and then washed with water by spraying. As the nitric acid aqueous solution used for the desmut treatment, the waste liquid of the step of performing an electrochemical surface roughening treatment using alternating current in the following nitric acid aqueous solution was used.

(D) Electrochemical roughening treatment An electrochemical roughening treatment was carried out continuously using an alternating voltage of 60 Hz. The electrolytic solution at this time was a 10.5 g / L aqueous solution of nitric acid (containing 5 g / L of aluminum ions and 0.007% by mass of ammonium ions) at a liquid temperature of 50 ° C. An electrochemical surface roughening treatment was performed using a carbon electrode as a counter electrode, using a trapezoidal rectangular wave alternating current with a time TP of 0.8 msec until the current value reaches a peak from zero and a duty ratio of 1: 1. Ferrite was used for the auxiliary anode. The electrolytic cell used was a radial cell type. The current density was 30 A / dm ² at the peak current value, and the amount of electricity was 220 C / dm 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. Then, water washing by spraying was performed.

(E) Alkaline etching treatment The aluminum plate was subjected to etching treatment at 32 ° C. using an aqueous solution having a caustic soda concentration of 26% by mass and an aluminum ion concentration of 6.5% by mass to dissolve the aluminum plate by 0.50 g / m ² . It was produced when electrochemical roughening treatment was performed using the alternating current in the previous stage.
The smut component mainly composed of aluminum hydroxide was removed, and the edge portion of the generated pit was dissolved to smooth the edge portion. Then, water washing by spraying was performed.

(F) Desmut treatment Desmut treatment by spraying was performed with a 15% by weight aqueous solution of sulfuric acid at a temperature of 30 ° C. (containing 4.5% by weight of aluminum ions), and then washed with water by spraying. The nitric acid aqueous solution used for the desmut treatment was a waste liquid from a process of performing an electrochemical surface roughening treatment using alternating current in a nitric acid aqueous solution.

(G) Electrochemical surface roughening treatment An electrochemical surface roughening treatment was performed continuously using an alternating voltage of 60 Hz. The electrolytic solution at this time was a hydrochloric acid 5.0 g / L aqueous solution (containing 5 g / L of aluminum ions) at a temperature of 35 ° C. An electrochemical surface roughening treatment was performed using a carbon electrode as a counter electrode, using a trapezoidal rectangular wave alternating current with a time TP of 0.8 msec until the current value reaches a peak from zero and a duty ratio of 1: 1. Ferrite was used for the auxiliary anode. The electrolytic cell used was a radial cell type. The current density was 25 A / dm ² at the peak current value, and the amount of electricity was 50 C / dm ² in terms of the total amount of electricity when the aluminum plate was the anode. Then, water washing by spraying was performed.

(H) Anodizing treatment Anodizing device of two-stage feeding electrolytic treatment method (first and second electrolytic section length 6 m each, first and second feeding section length 3 m each, first and second feeding electrode section length 2.4 m each) Anodizing was performed using this. The electrolytes supplied to the first and second electrolysis sections were both sulfuric acid concentration 50 g / L (containing 0.5 mass% of aluminum ions) and temperature 20 ° C. Then, water washing by spraying was performed. The final oxide film amount was 2.7 g / m ² .

  The aluminum plate which performed all the said (a)-(h) process is the support body 1, The aluminum plate which implemented only the process (d)-(h) is the support body 2, (d)-(f) and (h). The aluminum plate which performed only the process was used as the support body 3. When the center line average roughness (Ra indication according to JIS B0601) of each support was measured using a needle having a diameter of 2 μm, support 1 was 0.52 μm, support 2 was 0.28 μm, and support 3 was 0.3. It was 25 μm.

Supports 1 to 3 were immersed in a 40 ° C. aqueous solution containing 4 g / L of polyvinylphosphonic acid for 10 seconds, washed with tap water at 20 ° C. for 2 seconds, and dried to prepare Supports 4 to 6.
The following undercoat liquid 1 was applied to the supports 1 to 3 using a bar coater so as to have a dry coating amount of 2 mg / m ^2, and dried at 80 ° C. for 20 seconds to prepare supports 7 to 9.

[Undercoat liquid 1]
The following polymer (SP1) 0.3g
60.0g of pure water
Methanol 939.7g

    Polymer (SP1)

The following undercoat liquid 2 is applied to the supports 1 to 3 using a bar coater, and the dry coating amount is 20 mg / m ^2.
And dried at 80 ° C. for 20 seconds to prepare Supports 10-12.

[Undercoat liquid 2]
・ 200g of the following sol solution
・ Methanol 800g

Sol solution ・ Phosmer PE (Unichemical Co., Ltd.) 52g
・ Methanol 44g
・ Water 14g
・ 85% phosphoric acid 11g
・ Tetraethoxysilane 36g
・ 3-Methacryloxypropyltrimethoxysilane 12g

The following undercoat liquid 3 was applied to the supports 1 to 3 using a bar coater so as to have a dry coating amount of 2 mg / m ² and dried at 80 ° C. for 20 seconds to prepare supports 13 to 15.

[Undercoat 3]
The following polymer (SP2) 0.3g
60.0g of pure water
Methanol 939.7g

    Polymer (SP2)

[Formation of photosensitive layer]
<Photosensitive layer 1>
A photosensitive layer coating solution 1 having the following composition was coated on the support using a bar coater, and then dried at 90 ° C. for 1 minute to form a photosensitive layer 1. The dry coating amount of the photosensitive layer 1 was 1.35 g / m ² .

(Photosensitive layer coating solution 1)
1.69 parts by mass of the following polymerizable compound (Compound A) 1.87 parts by mass of the binder polymer described in Table 1 or 1.87 parts by mass of the following sensitizing dye (Compound B) 0.13 parts by mass of the following polymerization initiator (Compound C) 0.46 parts by mass 25% MEK dispersion of the following ε-phthalocyanine (F1) 1.70 parts by mass The following mercapto group-containing heterocyclic compound (Compound D) 0.34 parts by mass Fluorinated nonionic surfactant Megafac F-780F
(Dainippon Ink Chemical Co., Ltd.) 0.03 parts by mass Cuperon AL (manufactured by Wako Co., Ltd.) (tricresyl phosphate 10% solution)
0.12 parts by mass Methyl ethyl ketone 27.0 parts by mass Propylene glycol monomethyl ether 26.7 parts by mass
Novoperm Yellow H2G (manufactured by Clariant) 0.20 parts by mass

<Photosensitive layer 2>
A photosensitive layer coating solution 2 having the following composition was bar coated on the support, followed by oven drying at 100 ° C. for 44 seconds to form a photosensitive layer 2 having a dry coating amount of 1.3 g / m ² .

(Photosensitive layer coating solution 2)
Polymerizable compound (compound A) 0.52 g
0.45 g of binder polymer described in Table 1
Sensitizing dye (compound B) 0.04 g
Polymerization initiator (Compound C) 0.08 g
Mercapto group-containing heterocyclic compound (Compound D) 0.05 g
ε-phthalocyanine pigment dispersion 0.40 g
(Pigment: 15 parts by mass, dispersant: Polymer (1): 10 parts by mass,
Solvent: cyclohexanone / methoxypropyl acetate / 1-
(Methoxy-2-propanol = 15 parts by mass / 20 parts by mass / 40 parts by mass)
Thermal polymerization inhibitor 0.006g
(N-nitrosophenylhydroxylamine aluminum salt)
The following fluorosurfactant (1) 0.002 g
1-methoxy-2-propanol 8.0g
Methyl ethyl ketone 8.0g

[Formation of protective layer]
<Protective layer 1>
On the photosensitive layer, a protective layer coating solution having the following composition was coated with a bar coater so that the dry coating mass was 2.5 g / m ^2, and dried at 120 ° C. for 1 minute to form a protective layer 1.
(Protective layer coating solution)
PVA105 (saponification degree 98 mol%, manufactured by Kuraray Co., Ltd.) 1.80 parts by mass Polyvinylpyrrolidone 0.40 parts by mass EMALEX710 (Nonionic surfactant manufactured by Nippon Emulsifier Co., Ltd.) 0.04 parts by mass Pionein D230 (Takemoto Oil (Surfactant Co., Ltd.) 0.05 parts by mass Rubiscol V64W (manufactured by BASF) 0.06 parts by mass 13% aqueous solution of the following polymer 0.36 parts by mass Pure water 36.0 parts by mass

<Protective layer 2>
Protective layer 1 except that PVA105 was changed to GOCELAN CKS-50 (manufactured by Nippon Synthetic Chemical Co., Ltd., degree of saponification: 99 mol%, average degree of polymerization: 300, degree of modification: about 0.4 mol%) in protective layer 1 The protective layer 2 was formed in the same manner as the formation of 1.

<Protective layer 3>
On the photosensitive layer, polyvinyl alcohol (saponification degree 98 mol%, polymerization degree 500) 80% by mass, polyvinylpyrrolidone (BASF Corp., Rubiscor K-30) 17% by mass and surfactant Pionine D230 (Takemoto Yushi Co., Ltd.) )) Was applied with a wire bar with a wire bar, and dried at 125 ° C. for 75 seconds using a hot air dryer to form a protective layer 3 having a dry coating amount of 2.45 g / m ² .

<Protective layer 4>
On the photosensitive layer, a protective layer coating solution having the following composition was bar-coated, followed by oven drying at 125 ° C. for 70 seconds to form a protective layer having a dry coating amount of 1.25 g / m ² .
(Protective layer coating solution)
0.6 g of the following mica dispersion
0.8g of sulfonic acid-modified polyvinyl alcohol
(Goselan CKS-50, manufactured by Nippon Synthetic Chemical Co., Ltd. (degree of saponification:
99 mol%, average degree of polymerization: 300, degree of modification: about 0.4 mol%))
Poly (vinyl pyrrolidone / vinyl acetate (1/1)) (molecular weight: 70,000) 0.001 g
Surfactant (Emalex 710, manufactured by Nippon Emulsion Co., Ltd.) 0.002g
13g of water

(Mica dispersion)
To 368 g of water, 32 g of synthetic mica (Somasif ME-100, manufactured by Co-op Chemical Co., Ltd., aspect ratio: 1000 or more) is added, and dispersed using an homogenizer until the average particle size (laser scattering method) becomes 0.5 μm. A liquid was obtained.

  Lithographic printing plate precursors were prepared by combining the supports 4 to 15, the photosensitive layers 1 and 2 and the protective layers 1 to 4 as shown in Table 2 below.

[Exposure, development and printing]
Each of the above lithographic printing plate precursors was image-exposed with an FFEI Violet semiconductor laser plate setter Vx9600 (equipped with an InGaN-based semiconductor laser (with an emission wavelength of 405 nm ± 10 nm / output 30 mW)). The image was drawn with a resolution of 2438 dpi and an FM screen (TAFFETA 20) manufactured by Fuji Film Co., Ltd., and a 50% flat screen was drawn with a plate exposure amount of 0.05 mJ / cm ² .
Next, after preheating at 100 ° C. for 30 seconds, each processing solution having the following composition was used, and development processing was performed with an automatic developing processor having a structure as shown in FIG. The automatic processor has one brush roll with an outer diameter of 50 mm in which fibers made of polybutylene terephthalate (hair diameter 200 μm, hair length 17 mm) are implanted, and rotates 200 times per minute in the same direction as the conveying direction ( The peripheral speed of the brush tip was 0.52 m / sec). The temperature of the treatment liquid was 30 ° 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.

Treatment liquid 1 (pH 9.7)
8339.8 g of water
Sodium carbonate 130g
Sodium bicarbonate 70g
New Coal B13 (Nippon Emulsifier Co., Ltd.) 500g
Gum arabic (Mw = 200,000) 250g
700g of hydroxyalkylated starch
(Nippon Chemical: Penon JE66)
20g of primary ammonium phosphate
2-Bromo-2-nitropropane-1,3-diol 0.1 g
2-Methyl-4-isothiazolin-3-one 0.1 g

Treatment liquid 2 (pH 9.7)
8260g of water
150g potassium carbonate
Potassium bicarbonate 80g
ELEMINOL MON (100% conversion) (manufactured by Sanyo Chemical Co., Ltd.) 350g
800 g yellow dextrin
(Nissho Chemical: Akadama dextrin 102)
180 g of ammonic phosphate
180 g of sodium hexametaphosphate

Treatment liquid 3 (pH 9.5)
8260g of water
Sodium carbonate 160g
Sodium bicarbonate 160g
pionin C157K (100% conversion) (manufactured by Takemoto Yushi Co., Ltd.) 500 g
800 g yellow dextrin
(Nissho Chemical: Akadama dextrin 102)
180 g of ammonic phosphate
180 g of sodium hexametaphosphate

Treatment liquid 4 (pH 10.7)
8339.8 g of water
150g potassium carbonate
20g potassium bicarbonate
New Coal B13 (Nippon Emulsifier Co., Ltd.) 500g
Gum arabic (Mw = 200,000) 250g
700g of hydroxyalkylated starch
(Nippon Chemical: Penon JE66)
20g of primary ammonium phosphate
2-Bromo-2-nitropropane-1,3-diol 0.1 g
2-Methyl-4-isothiazolin-3-one 0.1 g

Treatment liquid 5 (pH 8.7)
8260g of water
Potassium carbonate 10g
130g potassium bicarbonate
ELEMINOL MON (100% conversion) (manufactured by Sanyo Chemical Co., Ltd.) 350g
800 g yellow dextrin
(Nissho Chemical: Akadama dextrin 102)
180 g of ammonic phosphate
180 g of sodium hexametaphosphate

Treatment liquid 6 (pH 9.9)
9379.8 g of water
Sodium carbonate 130g
Sodium bicarbonate 70g
New Coal B13 (Nippon Emulsifier Co., Ltd.) 500g
20g of primary ammonium phosphate
2-Bromo-2-nitropropane-1,3-diol 0.1 g
2-Methyl-4-isothiazolin-3-one 0.1 g

Comparative treatment solution 1 (pH 11.9)
8498.8 g of water
Potassium carbonate 17g
14g of potassium hydroxide (48%)
New Coal B13 (Nippon Emulsifier Co., Ltd.) 500g
Gum arabic (Mw = 200,000) 250g
700g of hydroxyalkylated starch
(Nippon Chemical: Penon JE66)
20g of primary ammonium phosphate
2-Bromo-2-nitropropane-1,3-diol 0.1 g
2-Methyl-4-isothiazolin-3-one 0.1 g

  The obtained lithographic printing plate is attached to a printing machine SOR-M manufactured by Heidelberg, and fountain solution (EU-3 (etch solution manufactured by FUJIFILM Corporation) / water / isopropyl alcohol = 1/89/10 (volume ratio). )) And TRANS-G (N) black ink (manufactured by Dainippon Ink & Chemicals, Inc.), printing was performed at a printing speed of 6000 sheets per hour.

[Evaluation]
Using each lithographic printing plate precursor, the developability, processability and printing durability were evaluated as follows.
<Developability>
Printing was performed using the planographic printing plate under the above conditions, and the 1000th printed material was evaluated for unevenness of the flat mesh image (unevenness of ink density) due to stains on the non-image area. When a flat screen image has no ink density unevenness and a good image is obtained: ○, When a flat screen image has slight ink density unevenness but an acceptable level: Δ, When a flat screen image has ink density unevenness : Evaluated as x.

<Processability>
When each lithographic printing plate precursor was developed for 500 m ² under the above conditions for 10 days, the state of occurrence of debris adhering to the wall of the automatic processor was visually observed. The generated residue is mainly caused by the binder of the protective layer. When no residue was generated: ◯, when residue was generated but at an acceptable level: Δ, and when residue was significant: x.

<Stain prevention>
Each lithographic printing plate was printed under the above conditions, and the blanket in the non-image area was visually evaluated after 10,000 sheets were printed. When there was no dirt on the blanket: ○, when there was almost no dirt on the blanket: Δ, when there was dirt on the blanket: evaluated as x.

<Print 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 2 weeks in an environment of temperature 28 ° C. and humidity 60%, then printed under the above conditions, and the printing durability (after 2 weeks) was similarly evaluated.
The evaluation results are shown in Table 2.

  From the results shown in Table 2, it can be seen that according to the method for preparing a lithographic printing plate of the present invention, a printed matter having no unevenness on the flat screen is obtained because of good developability, and no residue is formed in the developing tank. Furthermore, there is almost no decrease in printing durability due to the plate after development.

It is a schematic block diagram of the automatic developing apparatus 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)

A negative lithographic printing plate precursor having an image recording layer containing the following (i), (ii), (iii) and (iv) on a hydrophilic support is subjected to image exposure, and then carbonate ions and bicarbonate ions A method for preparing a lithographic printing plate , wherein the aqueous solution has a pH of 8.5 to 10.8 .
(I) Sensitizing dye (ii) Photopolymerization initiator (iii) Addition polymerizable compound having an ethylenically unsaturated double bond (iv) Binder polymer-L having a structure represented by formula (I) in the side chain ₁ —X—NH—Y—R ₁ (I)
(In the formula, L ₁ represents a single bond or a divalent linking group bonded to the polymer main chain. X and Y each independently represent a single bond or a divalent linking group, provided that X, Y At least one of — represents —SO ₂ —, and R ₁ represents a hydrogen atom or a monovalent organic group.) _{2. The} method for preparing a lithographic printing plate according to claim 1, wherein each of X and Y in the general formula (I) is —CO— or —SO ₂ —.   The method for preparing a lithographic printing plate according to claim 1 or 2, wherein the (i) sensitizing dye has an absorption maximum in a wavelength region of 350 nm to 450 nm.   The method for producing a lithographic printing plate according to any one of claims 1 to 3, wherein the image exposure is performed using a laser emitting light of 350 nm to 450 nm. The method for producing a lithographic printing plate according to any one of claims 1 to 4 , wherein the lithographic printing plate precursor further comprises a protective layer on the image recording layer. The method for preparing a lithographic printing plate according to claim 5 , wherein the protective layer contains acid-modified polyvinyl alcohol. The method for producing a lithographic printing plate according to any one of claims 1 to 6 , wherein the aqueous solution further contains a water-soluble polymer compound. The method for producing a lithographic printing plate according to any one of claims 1 to 7 , wherein the treatment with the aqueous solution is performed with one liquid.

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