JP2008015504A - Method for preparation of lithographic printing plate and lithographic printing plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To curb the influence of polymerization inhibition by oxygen in the air having action to deactivate radicals in a photosensitive layer generated by exposure, to improve discrimination of water resistance between an unexposed area and an exposed area with high sensitivity, and to achieve excellent printing durability, in a method for preparation of a lithographic printing plate in which post exposure is performed after exposure/development processing. <P>SOLUTION: A lithographic printing plate precursor having a photosensitive layer containing (A) a sensitizing dye, (B) a radical polymerization initiator, (C) a radical polymerizable compound and (D) a binder polymer and a protective layer in this order on a hydrophilic support is exposed to laser radiation, development processing is conducted to remove the protective layer and an unexposed area of the photosensitive layer, the exposed area of the photosensitive layer remaining on a surface of a lithographic printing plate is covered with a layer of liquid, and overall exposure of the lithographic printing plate to light having a wavelength capable of causing radical polymerization is performed. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

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

In general, a lithographic printing plate has a surface composed of an oleophilic image portion and a hydrophilic non-image portion. In lithographic printing, dampening water and oil-based ink are alternately applied to the plate surface, and the hydrophilic non-image area is dampened with a dampening water receiving area (ink non-receiving area) by utilizing the property that water and oil repel each other. ), And after the ink is received only in the oleophilic image area, the ink is transferred to a printing medium such as paper and printed.
In order to produce this lithographic printing plate, a lithographic printing plate precursor (PS plate) in which an oleophilic photosensitive layer (image recording layer) is provided on a hydrophilic support has been widely used. Usually, after exposing a lithographic printing plate precursor through an original image such as a lithographic film, the image recording layer to be an image portion is left, and other unnecessary image recording layers are washed with an alkaline developer or an organic solvent. The lithographic printing plate is obtained by carrying out plate making by a method in which the surface of the hydrophilic support is exposed by dissolving and removing to form a non-image portion.

  In the conventional plate making process of a lithographic printing plate precursor, a step of dissolving and removing unnecessary image recording layers with a developer or the like is necessary after exposure, but simplifies such additional wet processing. This is one of the issues. As one of simplification, it is desired that development can be performed with an aqueous solution close to neutrality or simple water.

  For example, Patent Document 1 discloses that an image forming layer of a lithographic printing plate precursor having an image forming layer containing a hydrophobizing precursor, a hydrophilic resin, and a photothermal conversion agent on a hydrophilic support, further contains an ethylene oxide chain. In addition to the on-press development, it is described that it can be used for printing after being exposed to a liquid development treatment using water or a suitable aqueous solution as a developer.

  Patent Document 2 contains (i) a hydrophilic support, and (ii) a radical polymerizable ethylenically unsaturated monomer, a radical polymerization initiator and an infrared absorbing dye, and is cured by infrared laser exposure. Moreover, a lithographic printing plate precursor comprising an oleophilic heat-sensitive layer containing 60% by mass or more of water and developable with an aqueous developer having a pH of 2.0 to 10.0 is prepared and exposed imagewise with an infrared laser. A processing method for a lithographic printing plate precursor comprising removing an uncured region of the heat-sensitive layer with an aqueous developer is described.

On the other hand, in recent years, digitization technology for electronically processing, storing, and outputting image information using a computer has become widespread, and various new image output methods corresponding to such digitization technology have been put into practical use. It has come to be. 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.
For use in such a CTP system, development of a lithographic printing plate precursor compatible with laser using radical polymerization reaction, which enables direct exposure of laser light to enable high-sensitivity and fine exposure, is in progress.
In the exposure process for a laser-compatible lithographic printing plate precursor using this radical polymerization reaction, the image recording layer is exposed to a laser beam and polymerized by causing a radical polymerization reaction in the exposed area of the image recording layer. Harden.

In this exposure process, oxygen in the air is a factor that hinders the radical polymerization reaction due to the action of inactivating radicals in the image recording layer generated by exposure. For this reason, the sensitivity of the lithographic printing plate precursor is lowered by the radical polymerization reaction being hindered by oxygen in the air in the exposed region of the image recording layer, and therefore it is difficult to increase the sensitivity to a certain extent.
Therefore, in the lithographic printing plate precursor, a protective layer such as PVA (polyvinyl alcohol) is formed on the image recording layer formed on the aluminum support to block oxygen in the air, and oxygen in the air records the image. Means are taken to increase the sensitivity so as not to enter the layer.

  Conventionally, in order to improve printing durability when making a lithographic printing plate precursor provided with an image recording layer for recording a latent image by radical photopolymerization as described above, post-exposure processing is performed after exposure and development processing, Alternatively, a lithographic printing plate precursor making method and a post-exposure device have been proposed in which a visible image portion formed on a developed lithographic printing plate is further polymerized and cured by heat treatment (for example, Patent Document 3). Patent Document 4, Patent Document 5, Patent Document 6, and Patent Document 7).

However, in the lithographic printing plate precursor making method and post-exposure apparatus that perform such post-exposure treatment, the protective layer is removed at the stage of development or pre-development treatment, so that the lithographic printing plate precursor is post-exposed. When performing the above, oxygen in the air having an action of deactivating radicals in the image recording layer generated by exposure enters the image recording layer and is greatly affected by polymerization inhibition by oxygen.
For this reason, in order to obtain a sufficient post-exposure effect, it is necessary to mount a large light source with very high illuminance on the post-exposure device, and there is a problem that the post-exposure device becomes large.
JP 2002-365789 A US Patent Application Publication No. 2004/0013968 JP 2001-48326 A JP 2001-51426 A Japanese Patent Laid-Open No. 2001-159811 Japanese Patent Laid-Open No. 11-265069 Japanese Patent Laid-Open No. 2002-162753

In order to maintain developability with respect to an aqueous developer having a pH of 2.0 to 10.0, the photosensitive layer needs to be hydrophilic or highly water-permeable. In the prior art, a photosensitive layer cured by exposure is used. The water resistance and film strength of the film were insufficient. In order to overcome this problem, it is necessary to improve the water resistance discrimination between the unexposed area and the exposed area in a reaction system with high sensitivity, that is, high curing efficiency.
An object of the present invention is a method for preparing a lithographic printing plate in which post-exposure processing is performed after exposure / development processing. Inhibition of polymerization inhibition by oxygen in the air having an action of inactivating radicals in a photosensitive layer generated by exposure. An object of the present invention is to provide a method for preparing a lithographic printing plate that suppresses the influence, has high sensitivity, improves the water resistance discrimination between the unexposed area and the exposed area, and has excellent printing durability, and the lithographic printing plate.

  The present invention is as follows.

(1) A photosensitive layer containing (A) a sensitizing dye, (B) a radical polymerization initiator, (C) a radical polymerizable compound and (D) a binder polymer on a hydrophilic support, and a protective layer. The lithographic printing plate precursors in order are subjected to a laser exposure, followed by a development treatment for removing the protective layer and the photosensitive layer of the non-exposed part, and then the photosensitive layer exposed part remaining on the surface of the lithographic printing plate A method for producing a lithographic printing plate, comprising covering with a liquid layer and exposing the entire surface with light having a wavelength causing radical polymerization.

  (2) On a hydrophilic support, (A) a sensitizing dye, (B) a radical polymerization initiator, (C) a radical polymerizable compound, and (D ′) a hydrophobic binder polymer having an acid value of 0.3 meq / g or less. A lithographic printing plate precursor having a photosensitive layer containing a protective layer and a protective layer in this order is subjected to laser exposure and then subjected to a rubbing member in the presence of a developer having a pH of 2 to 10 by an automatic processor equipped with a rubbing member. The surface of the photosensitive layer exposed portion remaining on the surface of the lithographic printing plate is covered with a liquid layer by developing the surface of the lithographic printing plate by removing the protective layer and the non-exposed portion of the photosensitive layer by rubbing the plate surface. A method for preparing a lithographic printing plate, comprising exposing the entire surface with light having a wavelength that causes polymerization.

  (3) The (A) sensitizing dye has an absorption maximum in the wavelength range of 350 to 450 nm, and the laser used for exposure is a laser having an oscillation wavelength in the wavelength range of 350 to 450 nm. The method for preparing a lithographic printing plate as described in (1) or (2) above.

  (4) The method for preparing a lithographic printing plate as described in any one of (1) to (3) above, wherein the radical polymerization initiator (B) is a hexaarylbiimidazole compound.

  (5) The method for preparing a lithographic printing plate as described in any one of (1) to (4) above, wherein the photosensitive layer further contains (E) a chain transfer agent.

  (6) The method for preparing a lithographic printing plate as described in (5) above, wherein the (E) chain transfer agent is a thiol compound represented by the following general formula (I).

  Here, R represents an alkyl group which may have a substituent, or an aryl group which may have a substituent, and A represents a 5-membered or 6-membered ring having a carbon atom together with an N═C—N moiety. The atomic group which forms the heterocyclic ring of A, and A may further have a substituent.

  (7) The (D) binder polymer is at least one selected from the group consisting of a (meth) acrylic acid copolymer having a crosslinkable group in the side chain and a polyurethane resin having a crosslinkable group in the side chain. The method for producing a lithographic printing plate as described in any one of (1) to (6) above, wherein:

  (8) The method for preparing a lithographic printing plate as described in any one of (1) to (7) above, wherein a part or all of the photosensitive layer component is encapsulated in a microcapsule.

  (9) The method for preparing a lithographic printing plate as described in any one of (2) to (8), wherein the rubbing member is at least two rotating brush rolls.

(10) The method of preparing a lithographic printing plate as described in any one of (2) to (9) above, wherein the developer has a pH of 3 to 8.
(11) A photosensitive layer containing (A) a sensitizing dye, (B) a radical polymerization initiator, (C) a radical polymerizable compound and (D) a binder polymer on a hydrophilic support, and a protective layer. The lithographic printing plate precursors in order are subjected to a laser exposure, followed by a development treatment for removing the protective layer and the photosensitive layer of the non-exposed part, and then the photosensitive layer exposed part remaining on the surface of the lithographic printing plate A lithographic printing plate produced by covering with a liquid layer and exposing the entire surface with light having a wavelength causing radical polymerization.

  According to the present invention, in the method of preparing a lithographic printing plate in which post-exposure processing is performed after exposure / development processing, the inhibition of polymerization by oxygen in the air has the effect of inactivating radicals in the photosensitive layer generated by exposure. It is possible to provide a method for preparing a lithographic printing plate and a lithographic printing plate that have high sensitivity, improve water resistance discrimination between an unexposed area and an exposed area, and have excellent printing durability.

[Lithographic printing plate precursor]
First, the planographic printing plate precursor used in the present invention will be described.

<Photosensitive layer>
The photosensitive layer of the present invention contains (A) a sensitizing dye, (B) a radical polymerization initiator, (C) a radical polymerizable compound, and (D) a binder polymer. Further, the photosensitive layer of the present invention can further contain other components as required. Hereinafter, the components of the photosensitive layer will be described in detail.

(A) Sensitizing dye The photosensitive layer of the present invention can contain a sensitizing dye corresponding to the wavelength of the exposure light source.
First, a sensitizing dye having a maximum absorption in the wavelength range of 350 to 450 nm suitable for the present invention will be described. Examples of such a sensitizing dye include merocyanine dyes represented by the following general formula (V), benzopyrans and coumarins represented by the following general formula (VI), and fragrances represented by the following general formula (VII). And anthracenes represented by the following general formula (VIII).

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

(In the formula, = 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 have the same meanings as those in the general formula (V); R _{7 to} R ₁₂ each independently represents a monovalent nonmetallic atomic group.)

(In the formula, Ar ₃ represents an aromatic group or a heteroaromatic group which may have a substituent, and R ₁₃ represents a monovalent non-metallic atomic group. More preferable R ₁₃ represents an aromatic group or It is a heteroaromatic group, and Ar ₃ and R ₁₃ may be bonded to each other to form a ring.)

(In the formula, X ₃ , X ₄ and R _{14 to} R ₂₁ each independently represent a monovalent non-metallic atomic group, and more preferable X ₃ and X ₄ are electron donating groups having a negative Hammett's substituent constant. .)

In the general formulas (V) to (VIII), 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, methoxy ester Toxiethyl 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, -Methyl-N- (sulfophenyl) carbamoylmethyl group, sulfobutyl group, sulfonatobutyl group, sulfamoylbutyl group, N-ethylsulfamoylmethyl group, N, N-dipropylsulfamoylpropyl group, N-tolylsulfa Moylpropyl group, N-methyl-N- (phosphonophenyl) sulfamoyloctyl group, phosphonobutyl group, phosphonatohexyl group, diethylphosphonobutyl group, diphenylphosphonopropyl group, methylphosphonobutyl group, methyl Phosphonatobutyl group, tolylphosphonohexyl group, tolylphosphonatohexyl 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-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, ethoxyphenylcarbonyl Phenoxycarbonylphenyl group, N-phenylcarbamoylphenyl group, phenyl 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, cynoline, pteridine, carbazole, carboline, phenanthrine, acridine, perimidine, phenanthroline, phthalazine, phenalzadi , Phenoxazine, furazane, phenoxazine, etc.), alkenyl group (eg, vinyl group, 1-propenyl group, 1-butenyl group, cinnamyl group, 2-chloro-1-ethenyl group, etc.), alkynyl group (eg, ethynyl group) 1-propynyl group, 1-butynyl group, trimethylsilylethynyl group, etc.), halogen atom (-F, -Br, -Cl, -I), hydroxyl group, 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-arylcal Vamoyloxy 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 group, N', N ' -Dialkyl-N-alkylureido groups, N ', N'-dialkyl-N-arylurees Group, N′-aryl-N-alkylureido group, N′-aryl-N-arylureido group, N ′, N′-diaryl-N-alkylureido group, N ′, N′-diaryl-N-aryl Ureido group, N′-alkyl-N′-aryl-N-alkylureido group, N′-alkyl-N′-aryl-N-arylureido group, alkoxycarbonylamino group, aryloxycarbonylamino 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, aryloxycarbonyl group, carbamoyl group, N-al Rucarbamoyl group, N, N-dialkylcarbamoyl group, N-arylcarbamoyl group, N, N-diarylcarbamoyl group, N-alkyl-N-arylcarbamoyl group, alkylsulfinyl group, arylsulfinyl 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-dialkylsulfina Moyl group, N-arylsulfinamoyl group, N, N-diarylsulfinamoyl group, N-alkyl-N-arylsulfinamoyl group, sulfamoyl group, N-alkylsulfamoyl group, N, N-dialkylsulfur group Famoyl group, N-a A reelsulfamoyl group, an N, N-diarylsulfamoyl group, an N-alkyl-N-arylsulfamoyl group, a phosphono group (—PO ₃ H ₂ ) and a conjugate base group thereof (hereinafter referred to as a 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) referred to as group), phosphonooxy group (-OPO ₃ H ₂₎ and its conjugated base group (hereinafter referred to as phosphonophenyl group , Dialkyl phosphonooxy group _{(-OPO 3 (alkyl) 2)} , diaryl phosphonooxy group _{(-OPO 3 (aryl) 2)} , alkylaryl phosphonooxy group _{(-OPO 3 (alkyl) (aryl} )), mono Alkylphosphonooxy group (—OPO ₃ H (alkyl)) and its conjugate base group (hereinafter referred to as alkylphosphonateoxy group), monoarylphosphonooxy group (—OPO ₃ H (aryl)) and its conjugate base Groups (hereinafter referred to as arylphosphonatooxy groups), cyano groups, nitro groups, and the like. Among the above substituents, hydrogen atoms, alkyl groups, aryl groups, halogen atoms, alkoxy groups, and acyl groups are particularly preferred. preferable.

  Examples of the basic nucleus of the dye formed together with A adjacent to Y in the general formula (V) and the adjacent carbon atom include 5-, 6-, and 7-membered nitrogen-containing or sulfur-containing heterocycles. A 5- or 6-membered heterocyclic ring is preferable.

  Examples of nitrogen-containing heterocycles include L. G. Brooker et al. , J. et al. Am. Chem. Soc. 73, 5326-5358 (1951). Any of those known to constitute a basic nucleus in the merocyanine dyes described in the literature and the references 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- Chlorobenzothiazole, 4-methylbenzothiazole, 5-methylbenzothiazole, 6-methylbenzothiazole, 5-bromobenzothiazole, 4-phenylbenzothiazole, 5-phenylbenzothiazole, 4-methoxybenzothiazole, 5-methoxybenzo Cheer , 6-methoxybenzothiazole, 5-iodobenzothiazole, 6-iodobenzothiazole, 4-ethoxybenzothiazole, 5-ethoxybenzothiazole, tetrahydrobenzothiazole, 5,6-dimethoxybenzothiazole, 5,6-di Oxymethylenebenzothiazole, 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.) , Chianafuteno 7 ′, 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-chloroben Zoxazole, 6-methoxybenzoxazole, 5-hydroxybenzoxazole, 6-hydroxybenzoxazole, etc.), naphthoxazoles (eg, naphtho [1,2] oxazole, naphtho [2,1] oxazole, etc.), selenazoles ( For example, 4-methylselenazole, 4-phenylselenazole, etc.), benzoselenazoles (for example, benzoselenazole, 5-chlorobenzoselenazole, 5-methoxybenzoselenazole, 5-hydroxybenzoselenazole, tetrahydrobenzo Selenazole etc.), naphthoselenazoles (eg naphtho [1,2] selenazole, naphtho [2,1] selenazole etc.), thiazolines (eg thiazoline, 4-methylthiazoline etc.), 2-quinolines (eg Quinoline, 3- Tilquinoline, 5-methylquinoline, 7-methylquinoline, 8-methylquinoline, 6-chloroquinoline, 8-chloroquinoline, 6-methoxyquinoline, 6-ethoxyquinoline, 6-hydroxyquinoline, 8-hydroxyquinoline, etc.), 4 -Quinolines (eg, quinoline, 6-methoxyquinoline, 7-methylquinoline, 8-methylquinoline, etc.), 1-isoquinolines (eg, isoquinoline, 3,4-dihydroisoquinoline, etc.), 3-isoquinolines (eg, , Isoquinoline, etc.), benzimidazoles (eg, 1,3-diethylbenzimidazole, 1-ethyl-3-phenylbenzimidazole, etc.), 3,3-dialkylindolenins (eg, 3,3-dimethylindolenin, 3,3,5-trimethylindolenine, 3,3 7, - trimethyl indolenine, etc.), 2-pyridines (e.g., pyridine, 5-methyl-pyridine, etc.), 4-pyridine (for example, a pyridine, etc.) or the like.

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] Dithiol etc.), dithiols (for example, 4,5-dimethyldithiols, 4-phenyldithiols, 4-methoxycarbonyldithiols, 4,5-dimethoxycarbonylbenzodithiols, 4,5-ditrifluoromethyldithiol, 4 , 5-dicyanodithiol, 4-methoxycarbonylmethyldithiol, 4-carboxymethyldithiol and the like.

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

  Among 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 (IX).

(In General Formula (IX), 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 hydrogen atom or a monovalent nonmetallic atomic group, and A and R ₁ and R ₂ and R ₃ are bonded to each other to form an aliphatic or aromatic ring. May be.)

General formula (IX) will be described in more detail. R ₁ , R ₂ and R ₃ are each independently a hydrogen atom or a monovalent nonmetallic atomic group, preferably a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, substituted or non-substituted It represents a substituted aryl group, a substituted or unsubstituted aromatic heterocyclic residue, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted alkylthio group, a hydroxyl group, and 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. Specific examples thereof include a methyl group, an ethyl group, a propyl group, Butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, hexadecyl, octadecyl, eicosyl, isopropyl, isobutyl, s-butyl, Examples thereof include t-butyl group, isopentyl group, neopentyl group, 1-methylbutyl group, isohexyl group, 2-ethylhexyl group, 2-methylhexyl group, cyclohexyl group, cyclopentyl group and 2-norbornyl group. 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, Reelsulfoxy 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 group, N ', N'-dialkyl-N-alkylureido group, N', 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-ary Luureido group, N′-alkyl-N′-aryl-N-alkylureido group, N′-alkyl-N′-aryl-N-arylureido group, alkoxycarbonylamino group, aryloxycarbonylamino 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, aryloxycarbonyl group, carbamoyl group, N-alkylcarbamoyl group, N, N-dialkylcarbamoyl group, N-arylcarbamoyl group, N, N-diarylcarbamoyl group, N-alkyl-N-arylcarbamoyl group , Alkylsul Finyl group, arylsulfinyl 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-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 conjugated base group (hereinafter, phospho Referred to as bets group), dialkyl phosphono group _{(-PO 3 (alkyl) 2)} , diaryl phosphono group _{(-PO 3 (aryl) 2)} , alkyl aryl 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 conjugate base group (Hereinafter referred to as aryl phosphonate group), phosphonooxy group (—OPO ₃ H ₂ ) and its conjugate base group (hereinafter referred to as phosphonateoxy group), dialkyl phosphonooxy group (—OPO ₃ (alkyl)) _2), diaryl phosphonooxy group (-OPO ₃ (aryl) _2), alkylaryl phosphonooxy group (-OPO ₃ alkyl) (aryl)), monoalkyl phosphonooxy group (-OPO ₃ H (alkyl)) and its conjugated base group (hereinafter referred to as alkyl phosphonophenyl group), monoaryl phosphonooxy group (-OPO ₃ H (Aryl)) and conjugated base groups thereof (hereinafter referred to as arylphosphonatooxy groups), cyano groups, nitro groups, aryl groups, heteroaryl groups, alkenyl groups, and alkynyl groups.

  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, ethoxyphenylcarbonyl group, phenoxycarbonylphenyl group, N-phenylcarbamoylphenyl group, phenyl group Cyanophenyl group, sulfophenyl group, sulfonatophenyl group, phosphonophenyl phenyl group, phosphonophenyl phenyl group and the like.

As the preferred heteroaryl group as R ₁ , R ₂ and R ₃ , a monocyclic or polycyclic aromatic ring containing at least one of nitrogen, oxygen and sulfur atoms is used. Examples of particularly preferred heteroaryl groups For example, thiophene, thiathrene, furan, pyran, isobenzofuran, chromene, xanthene, phenoxazine, pyrrole, pyrazole, isothiazole, isoxazole, pyrazine, pyrimidine, pyridazine, indolizine, isoindolizine, indolizine, indazole, Purine, quinolidine, isoquinoline, phthalazine, naphthyridine, quinazoline, sinoline, pteridine, carbazole, carboline, phenanthrine, acridine, perimidine, phenanthrolin, phthalazine, phenalazine, phenoxazine, flaza And phenoxazine and the like. These may be further benzo-fused and may have a substituent.

Examples of preferable alkenyl groups for R ₁ , R ₂ and R ₃ include vinyl groups, 1-
A propenyl group, a 1-butenyl group, a cinnamyl group, a 2-chloro-1-ethenyl group, and the like. Examples of the alkynyl group include an ethynyl group, a 1-propynyl group, a 1-butynyl group, and a trimethylsilylethynyl group. Can be mentioned. Examples of G ₁ in the acyl group (G ₁ CO—) include hydrogen and the above alkyl groups and aryl groups. Of these substituents, 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, formyl 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 Group, N-arylsulfa Yl 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 phosphine group Examples include an onato group, a phosphonooxy group, a phosphonateoxy 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 chains having 3 to 12 carbon atoms, and cyclic alkylene groups having 5 to 10 carbon atoms.

Specific examples of preferable substituted alkyl groups as R ₁ , R ₂ and R ₃ obtained by combining the substituent and the alkylene group include chloromethyl group, bromomethyl group, 2-chloroethyl group, trifluoromethyl group, methoxy Methyl 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- (phosphonophenyl) sulfamoyloctyl group, phosphonobutyl group, phosphonatohexyl group, diethylphosphonobutyl group, diphenylphosphonopropyl group, methylphosphonobutyl group, methylphosphonatobu Group, tolylphosphonohexyl group, tolylphosphonatohexyl group, phosphonooxypropyl group, phosphonateoxybutyl group, benzyl group, phenethyl group, α-methylbenzyl group, 1-methyl-1-phenylethyl group, p -Methylbenzyl group, cinnamyl 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. Can be mentioned.

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. 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 aforementioned aryl group. . 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 a biphenyl group, a tolyl group, a xylyl group, a mesityl group, a cumenyl group, a chlorophenyl group, a bromophenyl group, a fluorophenyl group, a chloromethylphenyl group, and a 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, carbo Cyphenyl group, methoxycarbonylphenyl group, allyloxycarbonylphenyl group, chlorophenoxycarbonylphenyl group, carbamoylphenyl group, N-methylcarbamoylphenyl group, N, N-dipropylcarbamoylphenyl group, N- (methoxyphenyl) carbamoylphenyl group N-methyl-N- (sulfophenyl) carbamoylphenyl group, sulfophenyl group, sulfonatophenyl group, sulfamoylphenyl group, N-ethylsulfamoylphenyl group, N, N-dipropylsulfamoylphenyl group, N-tolylsulfamoylphenyl group, N-methyl-N- (phosphonophenyl) sulfamoylphenyl group, phosphonophenyl group, phosphonatophenyl group, diethylphosphonophenyl group, diphenylphosphono Enyl group, methylphosphonophenyl group, methylphosphonatophenyl group, tolylphosphonophenyl group, tolylphosphonatophenyl group, allyl group, 1-propenylmethyl group, 2-butenyl group, 2-methylallylphenyl group, 2- Examples thereof include a methylpropenylphenyl group, a 2-propynylphenyl group, a 2-butynylphenyl group, and a 3-butynylphenyl group.

Next, A in the general formula (IX) will be described. A represents an aromatic ring or a hetero ring which may have a substituent. Specific examples of the aromatic ring or hetero ring which may have a substituent include R ₁ and R in the general formula (IX) similar to those described in ₂ and R ₃ can be exemplified.

  The sensitizing dye represented by the general formula (IX) of the present invention includes an acidic nucleus as shown above, an acidic nucleus having an active methylene group, a substituted or unsubstituted aromatic ring or heterocyclic ring, These can be synthesized by referring to Japanese Patent Publication No. 59-28329.

  Preferred specific examples (D1) to (D75) of the compound represented by the general formula (IX) 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.

Details of the usage, such as which structure of these sensitizing dyes are used, whether they are used alone or in combination of two or more, and how much is added, can be appropriately set in accordance with the performance design of the final photosensitive material .
For example, compatibility with the photosensitive composition layer can be enhanced by using two or more sensitizing dyes in combination. In selecting the sensitizing dye, in addition to the photosensitivity, the molar extinction coefficient at the emission wavelength of the light source used is an important factor. By using a dye having a large molar extinction coefficient, the amount of the dye added can be made relatively small, which is economical and advantageous from the viewpoint of film physical properties of the photosensitive layer when used in a lithographic printing plate precursor. is there. The photosensitivity and resolution of the photosensitive layer and the physical properties of the exposed film are greatly affected by the absorbance at the light source wavelength, and thus the addition amount of the sensitizing dye is appropriately selected in consideration of these.

  However, for example, for the purpose of curing a thick film having a thickness of 5 μm or more, the degree of curing may be increased by lower absorbance. When used as a lithographic printing plate used in a relatively thin film thickness, the addition amount of the sensitizing dye is such that the absorbance of the photosensitive layer of the present invention is in the range of 0.1 to 1.5, preferably 0.25 to 1. It is preferable to set so as to be in the range. Usually, the amount is preferably 0.05 to 30 parts by mass, more preferably 0.1 to 20 parts by mass, and most preferably 0.2 to 10 parts by mass with respect to 100 parts by mass of the total solid content of the photosensitive layer.

(B) Radical polymerization initiator Examples of the radical polymerization initiator used in the present invention include trihalomethyl compounds, carbonyl compounds, organic peroxides, azo compounds, azide compounds, metallocene compounds, hexaarylbiimidazole compounds, Examples thereof include organic boron compounds, disulfone compounds, oxime ester compounds, and onium salt compounds. Among these, at least one selected from the group consisting of hexaarylbiimidazole compounds, onium salts, trihalomethyl compounds, and metallocene compounds is preferable, and hexaarylbiimidazole compounds are particularly preferable. Two or more kinds of the polymerization initiators can be used in combination as appropriate.

  Examples of the hexaarylbiimidazole polymerization initiator include lophine dimers described in JP-B Nos. 45-37377 and 44-86516, such as 2,2′-bis (o-chlorophenyl) -4,4 ′, 5,5'-tetraphenylbiimidazole, 2,2'-bis (o-bromophenyl) -4,4 ', 5,5'-tetraphenylbiimidazole, 2,2'-bis (o, p-dichlorophenyl) ) -4,4 ', 5,5'-tetraphenylbiimidazole, 2,2'-bis (o-chlorophenyl) -4,4', 5,5'-tetra (m-methoxyphenyl) biimidazole, 2 , 2'-bis (o, o'-dichlorophenyl) -4,4 ', 5,5'-tetraphenylbiimidazole, 2,2'-bis (o-nitrophenyl) -4,4', 5,5 ′ − Traphenylbiimidazole, 2,2'-bis (o-methylphenyl) -4,4 ', 5,5'-tetraphenylbiimidazole, 2,2'-bis (o-trifluorophenyl) -4,4 ', 5,5'-tetraphenylbiimidazole and the like.

  The trihalomethyl compound is preferably trihalomethyl-s-triazine, 2,4,6-tris (trichloromethyl) -s-triazine, 2-methoxy-4,6-bis (trichloromethyl) -s-triazine, 2- Trimethyl compounds described in JP-A-58-29803 such as amino-4,6-bis (trichloromethyl) -s-triazine, 2- (P-methoxystyryl) -4,6-bis (trichloromethyl) -s-triazine and the like. Examples thereof include s-triazine derivatives having a halogen-substituted methyl group.

  Examples of the onium salt include onium salts represented by the following general formula (III).

In general formula (III), R ¹¹ , R ¹² and R ¹³ may be the same or different,
A hydrocarbon group having 20 or less carbon atoms which may have a substituent is shown. Preferable substituents include a halogen atom, a nitro group, an alkyl group having 12 or less carbon atoms, an alkoxy group having 12 or less carbon atoms, or an aryloxy group having 12 or less carbon atoms.
Z ⁻ represents a counter ion selected from the group consisting of halogen ion, perchlorate ion, tetrafluoroborate ion, hexafluorophosphate ion, carboxylate ion, and sulfonate ion, preferably perchlorate ion, hexa Fluorophosphate ions, carboxylate ions, and aryl sulfonate ions.

As the titanocene compound, for example, known compounds described in JP-A Nos. 59-152396 and 61-151197 can be appropriately selected and used.
Specifically, di-cyclopentadienyl-Ti-di-chloride, di-cyclopentadienyl-Ti-bis-phenyl, di-cyclopentadienyl-Ti-bis-2,3,4,5, 6-pentafluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2,3,5,6-tetrafluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2, 4,6-trifluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2,6-difluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2,4-difluoro Phen-1-yl, di-methylcyclopentadienyl-Ti-bis-2,3,4,5,6-pentafluorophen-1-yl, di-methylcyclopentadienyl-Ti-bis-2, 3, 5, 6 Tetrafluorophen-1-yl, di-methylcyclopentadienyl-Ti-bis-2,4-difluorophen-1-yl, bis (cyclopentadienyl) -bis [2,6-difluoro-3- ( Pyr-1-yl) phenyl] titanium and the like.

  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.

  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.

The polymerization initiator in the present invention is suitably used alone or in combination of two or more.
The amount of the polymerization initiator used in the photosensitive layer in the present invention is preferably 0.01 to 20% by mass, more preferably 0.1 to 15% by mass, based on the total solid content of the photosensitive layer. More preferably, it is 1.0 mass%-10 mass%.

(C) Radical polymerizable compound The radical polymerizable compound used in the photosensitive layer in the invention is an addition polymerizable compound having at least one ethylenically unsaturated double bond, and has at least one terminal ethylenically unsaturated bond, Preferably, it is selected from compounds having two or more. Such a compound group is widely known in the industrial field, and can be used without any particular limitation in the present invention. These have chemical forms such as monomers, prepolymers, i.e. dimers, trimers and oligomers, or mixtures thereof and copolymers thereof. Examples of monomers and copolymers thereof include unsaturated carboxylic acids (for example, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid, etc.), esters and amides thereof. In this case, an ester of an unsaturated carboxylic acid and an aliphatic polyhydric alcohol compound, or an amide of an unsaturated carboxylic acid and an aliphatic polyvalent amine compound is used. In addition, an addition reaction product of an unsaturated carboxylic acid ester or amide having a nucleophilic substituent such as a hydroxyl group, amino group or mercapto group with a monofunctional or polyfunctional isocyanate or epoxy, and monofunctional or polyfunctional A dehydration condensation reaction product with a functional carboxylic acid is also preferably used. Further, an addition reaction product of an unsaturated carboxylic acid ester or amide having an electrophilic substituent such as an epoxy group or an epoxy group with a monofunctional or polyfunctional alcohol, amine or thiol, a halogen group or Also suitable are substitution reaction products of unsaturated carboxylic acid esters or amides having a leaving substituent such as a tosyloxy group with monofunctional or polyfunctional alcohols, amines or thiols. As another example, it is also possible to use a group of compounds substituted with unsaturated phosphonic acid, styrene, vinyl ether or the like instead of the unsaturated carboxylic acid.

  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 hexaacrylate, sorbitol triacrylate, sorbitol tetraacrylate, sorbitol pentaacrylate, sorbitol hexaacrylate, tri (acryloyloxyethyl) isocyanurate, isocyanuric acid ethylene oxide (EO) Examples include modified triacrylates and 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, sorbitol trimethacrylate, sorbitol tetramethacrylate, bis [p- (3-methacryloxy- 2-hydroxypro ) 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.

  Examples of other esters include aliphatic alcohol esters described in JP-B-51-47334 and JP-A-57-196231, JP-A-59-5240, JP-A-59- Those having an aromatic skeleton described in JP-A No. 5241 and JP-A-2-226149 and those containing an amino group described in JP-A-1-165613 are also preferably used. Furthermore, the ester monomers described above can also be used as a mixture.

  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. -Methacrylamide, diethylenetriamine trisacrylamide, xylylene bisacrylamide, xylylene bismethacrylamide and the like. Examples of other preferable amide monomers include those having a cyclohexylene structure described in JP-B No. 54-21726.

  Further, urethane-based addition polymerizable compounds produced by using an addition reaction of isocyanate and hydroxyl group are also suitable. Specific examples thereof include, for example, one molecule described in JP-B-48-41708. A vinylurethane compound containing two or more polymerizable vinyl groups in one molecule obtained by adding a vinyl monomer containing a hydroxyl group represented by the following general formula (A) to a polyisocyanate compound having two or more isocyanate groups Etc.

_{CH 2 = C (R 4)} COOCH 2 CH (R 5) OH (A)
(However, R ₄ and R ₅ represent H or CH _3. )

  Also, urethane acrylates such as those described in JP-A-51-37193, JP-B-2-32293, JP-B-2-16765, JP-B-58-49860, JP-B-56- Urethane compounds having an ethylene oxide skeleton described in Japanese Patent No. 17654, Japanese Patent Publication No. 62-39417, and Japanese Patent Publication No. 62-39418 are also suitable. Furthermore, addition polymerizable compounds having an amino structure or a sulfide structure in the molecule described in JP-A-63-277653, JP-A-63-260909, and JP-A-1-105238 are used. Depending on the case, it is possible to obtain a photopolymerizable composition excellent in the photosensitive speed.

  Other examples include polyester acrylates, epoxy resins and (meth) acrylic acid as described in JP-A-48-64183, JP-B-49-43191, JP-B-52-30490, and JP-A-52-30490. Mention may be made of polyfunctional acrylates and methacrylates such as reacted epoxy acrylates. In addition, specific unsaturated compounds described in JP-B-46-43946, JP-B-1-40337, JP-B-1-40336, and vinylphosphonic acid-based compounds described in JP-A-2-25493 are also included. Can be mentioned. In some cases, a structure containing a perfluoroalkyl group described in JP-A-61-22048 is preferably used. Furthermore, Journal of Japan Adhesion Association vol. 20, no. 7, pages 300 to 308 (1984), which are introduced as photocurable monomers and oligomers, can also be used.

About these polymerizable compounds, the details of usage such as the structure, single use or combination, addition amount, etc. can be arbitrarily set according to the performance design of the final lithographic printing plate precursor. For example, it is selected from the following viewpoints.
From the viewpoint of sensitivity, a structure having a large unsaturated group content per molecule is preferable, and in many cases, a bifunctional or higher functionality is preferable. Further, in order to increase the strength of the image portion, that is, the cured film, those having three or more functionalities are preferable, and further, different functional numbers and different polymerizable groups (for example, acrylic acid ester, methacrylic acid ester, styrene compound, vinyl ether type). A method of adjusting both sensitivity and strength by using a compound) is also effective.
In addition, the compatibility and dispersibility with other components in the photosensitive layer (for example, binder polymer, polymerization initiator, colorant, etc.), the selection and use method of the polymerizable compound is an important factor. In some cases, the compatibility can be improved by using a low-purity compound or by using two or more kinds in combination. Also,
A specific structure may be selected for the purpose of improving adhesion to a support or a protective layer described later.

  The polymerizable compound is preferably used in the range of 5 to 80% by mass, more preferably 25 to 75% by mass, based on the total solid content of the photosensitive layer. These may be used alone or in combination of two or more. In addition, the usage of the polymerizable compound can be arbitrarily selected from the viewpoint of polymerization inhibition with respect to oxygen, resolution, fogging, refractive index change, surface adhesiveness, etc. The layer construction and coating method such as undercoating and overcoating can also be carried out.

(D) Binder polymer The binder polymer contained in the photosensitive composition in the present invention is a polymer that functions as a film-forming agent for the photosensitive layer.
As an example of such a binder polymer, a polymer selected from acrylic resins, polyvinyl acetal resins, polyurethane resins, polyamide resins, epoxy resins, methacrylic resins, styrene resins, and polyester resins is preferable. Of these, acrylic resins and polyurethane resins are preferable.

Further, the binder polymer can be cross-linked in order to improve the film strength of the image area.
In order to impart crosslinkability to the binder polymer, a crosslinkable functional group such as an ethylenically unsaturated bond may be introduced into the main chain or side chain of the polymer. The crosslinkable functional group may be introduced by copolymerization or may be introduced by a polymer reaction.

  Here, the crosslinkable group is a group that crosslinks the polymer binder in the process of radical polymerization reaction that occurs in the photosensitive layer when the lithographic printing plate precursor is exposed. Although it will not specifically limit if it is a group of such a function, For example, an ethylenically unsaturated bond group, an amino group, an epoxy group etc. are mentioned as a functional group which can be addition-polymerized. Moreover, the functional group which can become a radical by light irradiation may be sufficient, and as such a crosslinkable group, a thiol group, a halogen group, an onium salt structure etc. are mentioned, for example. Especially, an ethylenically unsaturated bond group is preferable and the functional group represented by the following general formula (1C)-(3C) is especially preferable.

In the general formula (1C), R ^{1 to} R ³ each independently represent a hydrogen atom or a monovalent organic group, and R ¹ is preferably a hydrogen atom or an alkyl which may have a substituent. A hydrogen atom or a methyl group is preferable because of high radical reactivity. R ² and R ³ are each independently a hydrogen atom, a halogen atom, an amino group, a carboxyl group, an alkoxycarbonyl group, a sulfo group, a nitro group, a cyano group, an optionally substituted alkyl group, or a substituted group. An aryl group which may have a group, an alkoxy group which may have a substituent, an aryloxy group which may have a substituent, an alkylamino group which may have a substituent, and a substituent An arylamino group which may have a substituent, an alkylsulfonyl group which may have a substituent, an arylsulfonyl group which may have a substituent, and the like. Among them, a hydrogen atom, a carboxyl group, an alkoxycarbonyl group, a substituent An alkyl group which may have a substituent and an aryl group which may have a substituent are preferable because of high radical reactivity.

X represents an oxygen atom, a sulfur atom, or N (R ¹² ) —, and R ¹² represents a hydrogen atom or a monovalent organic group. Here, examples of R ¹² include an alkyl group which may have a substituent. Among them, a hydrogen atom, a methyl group, an ethyl group, and an isopropyl group are preferable because of high radical reactivity.

  Here, examples of the substituent that can be introduced include an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an alkoxy group, an aryloxy group, a halogen atom, an amino group, an alkylamino group, an arylamino group, a carboxyl group, an alkoxycarbonyl group, A sulfo group, a nitro group, a cyano group, an amide group, an alkylsulfonyl group, an arylsulfonyl group and the like can be mentioned.

In the general formula (2C), R ^{4 to} R ⁸ each independently represents a hydrogen atom or a monovalent organic group, and R ^{4 to} R ⁸ are preferably a hydrogen atom, a halogen atom, an amino group, or a dialkyl. Amino group, carboxyl group, alkoxycarbonyl group, sulfo group, nitro group, cyano group, alkyl group which may have a substituent, aryl group which may have a substituent, alkoxy which may have a substituent A group, an aryloxy group which may have a substituent, an alkylamino group which may have a substituent, an arylamino group which may have a substituent, an alkylsulfonyl group which may have a substituent, Examples include an arylsulfonyl group which may have a substituent. Among them, a hydrogen atom, a carboxyl group, an alkoxycarbonyl group, an alkyl group which may have a substituent, and an aryl which may have a substituent. A group is preferred.

Examples of the substituent that can be introduced are the same as those in formula (1C). Y represents an oxygen atom, a sulfur atom, or N (R ¹² ) —. R ¹² has the same meaning as R ^{12 in} formula (1C), and preferred examples are also the same.

In the general formula (3C), R ⁹ is preferably a hydrogen atom or an alkyl group which may have a substituent, among which a hydrogen atom or a methyl group has high radical reactivity. preferable. R ¹⁰ and R ¹¹ are each independently a hydrogen atom, a halogen atom, an amino group, a dialkylamino group, a carboxyl group, an alkoxycarbonyl group, a sulfo group, a nitro group, a cyano group, or an alkyl group which may have a substituent. An aryl group which may have a substituent, an alkoxy group which may have a substituent, an aryloxy group which may have a substituent, an alkylamino group which may have a substituent, An arylamino group which may have, an alkylsulfonyl group which may have a substituent, an arylsulfonyl group which may have a substituent, etc. are mentioned, among them, a hydrogen atom, a carboxyl group, an alkoxycarbonyl group, An alkyl group which may have a substituent and an aryl group which may have a substituent are preferable because of high radical reactivity.

Here, examples of the substituent that can be introduced are the same as those in the general formula (1C). Further, Z is an oxygen atom, a sulfur atom, -N (R ¹³⁾ -, or a phenylene group which may have a substituent. Examples of R ¹³ include an alkyl group which may have a substituent. Among them, a methyl group, an ethyl group, and an isopropyl group are preferable because of high radical reactivity.
Among these, (meth) acrylic acid copolymers having a crosslinkable group in the side chain and polyurethane are more preferable.

  In the case of a binder polymer having crosslinkability, for example, free radicals (polymerization initiation radicals or growth radicals in the polymerization process of a polymerizable compound) are added to the crosslinkable functional group, and a polymerization chain of a polymerizable compound is formed directly between polymers. Through addition polymerization, a cross-link is formed between the polymer molecules and cured. Alternatively, atoms in the polymer (eg, hydrogen atoms on carbon atoms adjacent to the functional bridging group) are abstracted by free radicals to form polymer radicals that are bonded to each other so that crosslinking between the polymer molecules occurs. Forms and cures.

  The content of the crosslinkable group in the binder polymer (content of unsaturated double bond capable of radical polymerization by iodine titration) is preferably 0.1 to 10.0 mmol, more preferably 1 per 1 g of the hydrophobic binder polymer. 0.0 to 7.0 mmol, most preferably 2.0 to 5.5 mmol.

Further, the binder polymer to be used is appropriately selected according to the mode of the development treatment so that the non-image area of the photosensitive layer can be satisfactorily removed in the plate making process of the lithographic printing plate precursor.
In an embodiment carried out using an alkaline developer having a pH exceeding 10, the binder polymer needs to be dissolved in the alkaline developer, and therefore an organic high molecular polymer that is soluble or swellable in alkaline water is preferably used. .
As such a binder polymer, a polymer having at least a structural unit represented by the following general formulas (1) to (3) is preferable.

In the formula, each of R ₁ , R ₂ and R ₃ independently represents a hydrogen atom or a C 1 to C 6 alkyl group, and X represents —COOH, —CO—W 1 -L 1 —COOH, or —SO ₃ H. W1 represents an oxygen atom, sulfur atom, or —NH— group, L1 represents a divalent organic group, Y represents —CO—O—CH ₂ —CH═CH ₂ group, —CO indicates _-W2-L2-O-CO- CR 4 = CH 2 group, W2 is an oxygen atom, a sulfur atom or an -NH- group indicates L2 is a divalent organic radical,, _{R 4} is a hydrogen atom or, C1 to C6 represents an alkyl group, W3 represents an oxygen atom, a sulfur atom, or —NH— group, R ₅ represents a C1 to C18 alkyl group, C5 to C20 alkyl group having an alicyclic structure, or C6 to C20 And a group having an aromatic ring. Specific examples of the structural units represented by the formulas (1) to (3) are described below, but the present invention is not limited to these.
Specific examples of formula (1) include the structural units shown below.

  Specific examples of formula (2) include the structural units shown below.

  Specific examples of the monomer that forms the structural unit of the formula (3) include methyl (meth) acrylate, ethyl (meth) acrylate, isobutyl (meth) acrylate, normal butyl (meth) acrylate, isopropyl (meth) acrylate, cyclohexyl ( Alkyl or aryl (meth) acrylates such as (meth) acrylate, n-hexyl (meth) acrylate, adamantyl (meth) acrylate, benzyl (meth) acrylate, phenethyl (meth) acrylate, (meth) acrylate represented by the following formula Is mentioned. (In the following formula, preferred substituents for R include methyl group, ethyl group, isopropyl group, n-butyl group, t-butyl group, cyclohexyl group, phenethyl group, benzyl group, and n-hexyl group.)

In order to maintain the developability of the photosensitive layer, the binder polymer used preferably has an appropriate molecular weight and acid value, and has a weight average molecular weight of 5000 to 300,000 and an acid value of 0.3 to 4 meq / g. A molecular polymer is particularly preferably used.
(3) The use ratio of the addition polymerizable compound having an ethylenically unsaturated double bond contained in the structural unit is 0.1 to 3.0 in terms of mass ratio when the whole binder polymer is 1. It is preferable to set it as a range, More preferably, it is 0.1-2.0, Most preferably, it is 0.1-1.0.

As long as the above molecular weight, acid value, and double bond amount are satisfied, the mixing ratio of (1), (2), and (3) may be any combination. As long as these are satisfied, structural units other than the above (1) to (3) may be further added.
The binder polymer can be contained in an arbitrary amount in the photosensitive layer, but when it exceeds 90% by mass in all the components of the photosensitive composition, it does not give a preferable result in terms of image strength to be formed. Therefore, it is preferably 10 to 90% by mass, more preferably 30 to 80% by mass.

Next, a hydrophobic binder polymer suitable for forming a photosensitive layer that can be developed with an aqueous developer (non-alkaline developer) having a pH of 2 to 10 will be described.
As the hydrophobic binder polymer that can be used in the photosensitive layer that can be developed with a non-alkali developer, a water-insoluble polymer is preferably used. Furthermore, the hydrophobic binder polymer that can be used in the present invention preferably contains substantially no acid group such as a carboxyl group, a sulfone group, and a phosphoric acid group. The acid value of the binder polymer (acid content per gram of polymer) In terms of the number of chemical equivalents) is preferably 0.3 meq / g or less, and more preferably 0.1 meq / g or less.
That is, the hydrophobic binder polymer that can be used in the present invention is preferably insoluble in water and an aqueous solution of pH 10 or higher, and the solubility of the hydrophobic binder polymer in water and an aqueous solution of pH 10 or higher (polymer concentration at the time of saturated dissolution). However, it is preferable that it is 0.5 mass% or less, More preferably, it is 0.1 mass% or less. By using such a hydrophobic binder polymer, the film strength, water resistance and wall-thickness of the photosensitive layer are improved, and printing durability is improved. The solubility measuring temperature is a temperature during plate-making development, and is 25 ° C. here.

As the hydrophobic binder polymer, as long as the performance of the lithographic printing plate of the present invention is not impaired, a conventionally known one can be used without limitation within the above range, and a linear organic polymer having a film property is preferable.
As an example of such a hydrophobic binder polymer, a polymer selected from acrylic resin, polyvinyl acetal resin, polyurethane resin, polyamide resin, epoxy resin, methacrylic resin, styrene resin, and polyester resin is preferable. Especially, an acrylic resin is preferable and a (meth) acrylic acid ester copolymer is preferable. More specifically, an alkyl (meth) acrylate or an aralkyl ester and an ester residue (—COOR) of (meth) acrylate ester may have a —CH ₂ CH ₂ O— unit or a —CH ₂ CH ₂ NH— unit as R. A copolymer with a (meth) acrylic acid ester containing is particularly preferred. The preferable alkyl group of the said (meth) acrylic-acid alkylester is a C1-C5 alkyl group, and a methyl group is more preferable. Preferable (meth) acrylic acid aralkyl esters include benzyl (meth) acrylate.

The hydrophobic binder polymer can also be cross-linked to improve the film strength of the image area.
In order to impart crosslinkability to the hydrophobic binder polymer, a crosslinkable functional group such as an ethylenically unsaturated bond may be introduced into the main chain or side chain of the polymer. The crosslinkable functional group may be introduced by copolymerization or may be introduced by a polymer reaction.
Examples of the crosslinkable functional group include the crosslinkable groups described above, and the functional groups represented by the general formulas (1C) to (3C) are particularly preferable.

  Further, it is preferable that the binder polymer is hydrophilic from the viewpoint of improving developability with respect to an aqueous solution, and it is important that the binder polymer is compatible with the polymerizable compound contained in the photosensitive layer from the viewpoint of improving printing durability. Yes, ie lipophilic. From such a viewpoint, in the present invention, it is also effective to copolymerize a hydrophilic group and a lipophilic group in a hydrophobic binder polymer in order to improve developability and printing durability. Examples of the hydrophilic group include a hydroxy group, a carboxylate group, a hydroxyethyl group, an ethyleneoxy group, a hydroxypropyl group, a polyoxyethyl group, a polyoxypropyl group, an amino group, an aminoethyl group, an aminopropyl group, and an ammonium group. And those having a hydrophilic group such as an amide group or a carboxymethyl group.

The hydrophobic binder polymer preferably has a mass average molecular weight of 5,000 or more, more preferably 10,000 to 300,000, and a number average molecular weight of 1,000 or more, preferably 2000 to 250,000. Is more preferable. The polydispersity (mass average molecular weight / number average molecular weight) is preferably 1.1 to 10.
The hydrophobic binder polymer may be any of a random polymer, a block polymer, a graft polymer, and the like, but is preferably a random polymer.

The hydrophobic binder polymer may be used alone or in combination of two or more.
The content of the hydrophobic binder polymer is 5 to 90% by mass, preferably 10 to 70% by mass, and more preferably 10 to 60% by mass with respect to the total solid content of the photosensitive layer. Within this range, good image area strength and image formability can be obtained.

(E) Chain transfer agent The photosensitive layer of the invention preferably contains a chain transfer agent. Chain transfer agents contribute to improved sensitivity and storage stability. As the compound that acts as a chain transfer agent, for example, a compound group having SH, PH, SiH, GeH in the molecule is used. These can donate hydrogen to low-activity radical species to generate radicals, or can be oxidized and then deprotonated to generate radicals.

In the photosensitive layer of the present invention, in particular, a thiol compound (for example, 2-mercaptobenzimidazoles) can be preferably used as a chain transfer agent.
Among these, a thiol compound represented by the following general formula (I) is particularly preferably used. By using this thiol compound as a chain transfer agent, the problem of odor and sensitivity reduction due to evaporation from the photosensitive layer and diffusion to other layers are avoided, and it has excellent storage stability and high sensitivity and high printing durability. A lithographic printing plate precursor is obtained.

  In general formula (I), R represents an alkyl group which may have a substituent or an aryl group which may have a substituent, and A represents a 5-membered ring having a carbon atom together with an N = CN moiety. Alternatively, it represents an atomic group that forms a 6-membered heterocycle, and A may further have a substituent.

  More preferably, those represented by the following general formula (IA) or general formula (IB) are used.

  In general formulas (IA) and (IB), R represents an alkyl group which may have a substituent or an aryl group which may have a substituent, and X represents a halogen atom, an alkoxyl group or a substituent. The alkyl group which may have or the aryl group which may have a substituent is represented.

  Specific examples of the compound represented by formula (I) are shown below, but the present invention is not limited to these.

  The amount of these thiol compounds used is preferably 0.01 to 20% by mass, more preferably 0.1 to 15% by mass, based on the total solid content of the photosensitive layer. More preferably, it is 1.0-10 mass%.

<Microcapsule>
In the present invention, as a method for causing the photosensitive layer to contain the above-described photosensitive layer constituents and other constituents described later, for example, as described in JP-A Nos. 2001-277740 and 2001-277742, A part of the components can be encapsulated in microcapsules and added to the photosensitive layer. In that case, each component can be contained in any ratio in and out of the microcapsule.

As a method for microencapsulating the photosensitive layer constituent components, known methods can be applied. For example, as a method for producing microcapsules, a method using coacervation found in U.S. Pat. Nos. 2,800,547 and 2,800,498, U.S. Pat. No. 3,287,154, JP-B-38-19574, 42-446 by the interfacial polymerization method, US Pat. No. 3,418,250, US Pat. No. 3,660,304 by polymer precipitation method, US Pat. No. 3,796,669, isocyanate polyol A method using a wall material, a method using an isocyanate wall material found in US Pat. No. 3,914,511, and a urea-formaldehyde system found in US Pat. Nos. 4,001,140, 4,087,376 and 4,089,802. Or urea formaldehyde-resorcino A method using a wall forming material, a method using a wall material such as melamine-formaldehyde resin and hydroxycellulose, as shown in US Pat. No. 4,025,445, and Japanese Patent Publication Nos. 36-9163 and 51-9079. In situ method using monomer polymerization, spray drying method found in British Patent No. 930422, US Pat. No. 3,111,407, electrolytic dispersion cooling method seen in British Patent Nos. 952807 and 967074, etc. However, it is not limited to these.

  A preferable microcapsule wall used in the present invention has a three-dimensional cross-linking and has a property of swelling with a solvent. From such a viewpoint, the wall material of the microcapsule is preferably polyurea, polyurethane, polyester, polycarbonate, polyamide, and a mixture thereof, and particularly preferably polyurea and polyurethane. Moreover, you may introduce | transduce into the microcapsule wall the compound which has crosslinkable functional groups, such as an ethylenically unsaturated bond which can be introduce | transduced into said water-insoluble polymer.

  The average particle size of the microcapsules is preferably 0.01 to 3.0 μm. 0.05-2.0 micrometers is further more preferable, and 0.10-1.0 micrometer is especially preferable. Within this range, good resolution and stability over time can be obtained.

<Other photosensitive layer components>
The photosensitive layer of the present invention can further contain various additives as required. These will be described below.

<Surfactant>
In the present invention, it is preferable to use a surfactant in the photosensitive layer in order to promote developability and improve the coated surface state. Examples of the surfactant include nonionic surfactants, anionic surfactants, cationic surfactants, amphoteric surfactants, and fluorosurfactants. Surfactant may be used independently and may be used in combination of 2 or more type.

  The nonionic surfactant used for this invention is not specifically limited, A conventionally well-known thing can be used. For example, polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene polystyryl phenyl ethers, polyoxyethylene polyoxypropylene alkyl ethers, glycerin fatty acid partial esters, sorbitan fatty acid partial esters, pentaerythritol Fatty acid partial esters, propylene glycol mono fatty acid esters, sucrose fatty acid partial esters, polyoxyethylene sorbitan fatty acid partial esters, polyoxyethylene sorbitol fatty acid partial esters, polyethylene glycol fatty acid esters, polyglycerin fatty acid partial esters, Polyoxyethylenated castor oil, polyoxyethylene glycerin fatty acid partial esters, fatty acid diethanolamides, N N- bis-2-hydroxyalkylamines, polyoxyethylene alkylamines, triethanolamine fatty acid ester, trialkylamine oxide, polyethylene glycol, copolymers of polyethylene glycol and polypropylene glycol.

The anionic surfactant used in the present invention is not particularly limited, and conventionally known anionic surfactants can be used. For example, fatty acid salts, abietic acid salts, hydroxyalkane sulfonates, alkane sulfonates, dialkyl sulfosuccinate esters, linear alkyl benzene sulfonates, branched alkyl benzene sulfonates, alkyl naphthalene sulfonates, alkyl phenoxy poly Oxyethylene propyl sulfonates, polyoxyethylene alkyl sulfophenyl ether salts, N-methyl-N-oleyl taurine sodium salt, N-alkyl sulfosuccinic acid monoamide disodium salt, petroleum sulfonates, sulfated beef oil, fatty acid alkyl esters Sulfates, alkyl sulfates, polyoxyethylene alkyl ether sulfates, fatty acid monoglyceride sulfates, polyoxyethylene alcohol Ruphenyl ether sulfates, polyoxyethylene styryl phenyl ether sulfates, alkyl phosphates, polyoxyethylene alkyl ether phosphates, polyoxyethylene alkyl phenyl ether phosphates, styrene / maleic anhydride Examples thereof include partial saponification products of polymers, partial saponification products of olefin / maleic anhydride copolymers, and naphthalene sulfonate formalin condensates.

The cationic surfactant used in the present invention 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.
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 acid 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.

  More preferable surfactants include fluorine-based surfactants containing a perfluoroalkyl group in the molecule. Examples of such fluorosurfactants include anionic types such as perfluoroalkyl carboxylates, perfluoroalkyl sulfonates, and perfluoroalkyl phosphates; amphoteric types such as perfluoroalkyl betaines; Cation type such as trimethylammonium salt; perfluoroalkylamine oxide, perfluoroalkylethylene oxide adduct, oligomer containing perfluoroalkyl group and hydrophilic group, oligomer containing perfluoroalkyl group and lipophilic group, perfluoroalkyl Nonionic types such as an oligomer containing a group, a hydrophilic group and a lipophilic group, and a urethane containing a perfluoroalkyl group and a lipophilic group. Also preferred are the fluorosurfactants described in JP-A-62-170950, JP-A-62-226143 and JP-A-60-168144.

Surfactant can be used individually or in combination of 2 or more types.
The content of the surfactant is preferably 0.001 to 10% by mass and more preferably 0.01 to 7% by mass with respect to the total solid content of the photosensitive layer.

<Hydrophilic polymer>
In the present invention, a hydrophilic polymer can be contained in order to improve the developability and the dispersion stability of the microcapsules.
Examples of the hydrophilic polymer include hydroxy group, carboxyl group, carboxylate group, hydroxyethyl group, polyoxyethyl group, hydroxypropyl group, polyoxypropyl group, amino group, aminoethyl group, aminopropyl group, ammonium group, Preferred are those having a hydrophilic group such as an amide group, carboxymethyl group, sulfonic acid group, and phosphoric acid group.

Specific examples include gum arabic, casein, gelatin, starch derivatives, carboxymethylcellulose and its sodium salt, cellulose acetate, sodium alginate, vinyl acetate-maleic acid copolymers, styrene-maleic acid copolymers, polyacrylic acids and their salts, Polymethacrylic acids and their salts, homopolymers and copolymers of hydroxyethyl methacrylate, homopolymers and copolymers of hydroxyethyl acrylate, homopolymers and copolymers of hydroxypropyl methacrylate, homopolymers and copolymers of hydroxypropyl acrylate, homopolymers of hydroxybutyl methacrylate Polymers and copolymers, homopolymers and copolymers of hydroxybutyl acrylate Polyethylene glycols, hydroxypropylene polymers, polyvinyl alcohols, hydrolyzed polyvinyl acetate, polyvinyl formal, polyvinyl butyral, polyvinyl pyrrolidone, acrylamide homopolymers and copolymers having a hydrolysis degree of 60 mol% or more, preferably 80 mol% or more , Methacrylamide homopolymers and polymers, N-methylolacrylamide homopolymers and copolymers, polyvinylpyrrolidone, alcohol-soluble nylon, polyether of 2,2-bis- (4-hydroxyphenyl) -propane and epichlorohydrin, etc. Is mentioned.

The hydrophilic polymer preferably has a mass average molecular weight of 5000 or more, more preferably 10,000 to 300,000. The hydrophilic polymer may be any of a random polymer, a block polymer, a graft polymer, and the like.
The content of the hydrophilic polymer in the photosensitive layer is preferably 20% by mass or less, more preferably 10% by mass or less, based on the total solid content of the photosensitive layer.

<Colorant>
In the present invention, a dye having a large absorption in the visible light region can be used as an image colorant. Specifically, Oil Yellow # 101, Oil Yellow # 103, Oil Pink # 312, Oil Green BG, Oil Blue BOS, Oil Blue # 603, Oil Black BY, Oil Black BS, Oil Black T-505 (orientated chemistry) Kogyo Co., Ltd.), Victoria Pure Blue, Crystal Violet (CI42555), Methyl Violet (CI42535), Ethyl Violet, Rhodamine B (CI145170B), Malachite Green (CI42000), Methylene Blue (CI522015), etc. And dyes described in Japanese Patent No. 293247. Also, pigments such as phthalocyanine pigments, azo pigments, carbon black, titanium oxide, etc. can be suitably used.

  These colorants are preferably added since it is easy to distinguish an image area from a non-image area after image formation. The amount added is preferably 0.01 to 10% by mass with respect to the total solid content of the image recording material.

<Bakeout agent>
In the photosensitive layer of the present invention, a compound that changes color by an acid or a radical can be added in order to form a printout image. As such a compound, for example, various dyes such as diphenylmethane, triphenylmethane, thiazine, oxazine, xanthene, anthraquinone, iminoquinone, azo, and azomethine are effectively used.

Specific examples include brilliant green, ethyl violet, methyl green, crystal violet, basic fuchsin, methyl violet 2B, quinaldine red, rose bengal, methanyl yellow, thymol sulfophthalein, xylenol blue, methyl orange, paramethyl red, Congo Fred, Benzopurpurin 4B, α-Naphthyl Red, Nile Blue 2B, Nile Blue A, Methyl Violet, Malachide Green, Parafuchsin, Victoria Pure Blue BOH [manufactured by Hodogaya Chemical Co., Ltd.], Oil Blue # 603 [Orient Chemical Kogyo Co., Ltd.], Oil Pink # 312 [Orient Chemical Co., Ltd.], Oil Red 5B [Orient Chemical Co., Ltd.], Oil Scarlet # 308 [Orient Gaku Kogyo Co., Ltd.], Oil Red OG [Orient Chemical Co., Ltd.], Oil Red RR [Orient Chemical Co., Ltd.], Oil Green # 502 [Orient Chemical Co., Ltd.], Spiron Red BEH Special [made by Hodogaya Chemical Co., Ltd.], m-cresol purple, cresol red, rhodamine B, rhodamine 6G, sulforhodamine B, auramine, 4-p-diethylaminophenyliminonaphthoquinone, 2-carboxyanilino-4-p- Diethylaminophenyliminonaphthoquinone, 2-carboxystearylamino-4-pN, N-bis (hydroxyethyl) amino-phenyliminonaphthoquinone, 1-phenyl-3-methyl-4-p-diethylaminophenylimino-5-pyrazolone, 1-β-naphthyl-4- - dyes and p of diethylamino phenyl imino-5-pyrazolone, p ', p "- hexamethyl triamnotriphenylmethane (leuco crystal violet), and a leuco dye such as Pergascript Blue SRB (manufactured by Ciba-Geigy).

  In addition to the above, a leuco dye known as a material for thermal paper or pressure-sensitive paper is also suitable. Specific examples include crystal violet lactone, malachite green lactone, benzoylleucomethylene blue, 2- (N-phenyl-N-methylamino) -6- (Np-tolyl-N-ethyl) amino-fluorane, 2-anilino. -3-methyl-6- (N-ethyl-p-toluidino) fluorane, 3,6-dimethoxyfluorane, 3- (N, N-diethylamino) -5-methyl-7- (N, N-dibenzylamino) ) -Fluorane, 3- (N-cyclohexyl-N-methylamino) -6-methyl-7-anilinofluorane, 3- (N, N-diethylamino) -6-methyl-7-anilinofluorane, 3 -(N, N-diethylamino) -6-methyl-7-xylidinofluorane, 3- (N, N-diethylamino) -6-methyl-7-chloro Fluorane, 3- (N, N-diethylamino) -6-methoxy-7-aminofluorane, 3- (N, N-diethylamino) -7- (4-chloroanilino) fluorane, 3- (N, N-diethylamino) -7-chlorofluorane, 3- (N, N-diethylamino) -7-benzylaminofluorane, 3- (N, N-diethylamino) -7,8-benzofluorane, 3- (N, N-dibutyl) Amino) -6-methyl-7-anilinofluorane, 3- (N, N-dibutylamino) -6-methyl-7-xylidinofluorane, 3-piperidino-6-methyl-7-anilinofluorane 3-pyrrolidino-6-methyl-7-anilinofluorane, 3,3-bis (1-ethyl-2-methylindol-3-yl) phthalide, 3,3-bis (1-n-butyl- -Methylindol-3-yl) phthalide, 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide, 3- (4-diethylamino-2-ethoxyphenyl) -3- (1-ethyl- 2-methylindol-3-yl) -4-zaphthalide, 3- (4-diethylaminophenyl) -3- (1-ethyl-2-methylindol-3-yl) phthalide, and the like.

  A suitable addition amount of the dye that changes color by acid or radical is 0.01 to 15% by mass relative to the solid content of the photosensitive layer.

<Polymerization inhibitor>
It is preferable to add a small amount of a thermal polymerization inhibitor to the photosensitive layer of the present invention in order to prevent unnecessary thermal polymerization of the radical polymerizable compound during the production or storage of the photosensitive layer.
Examples of the thermal polymerization inhibitor include hydroquinone, p-methoxyphenol, di-t-butyl-p-cresol, pyrogallol, t-butylcatechol, benzoquinone, 4,4'-thiobis (3-methyl-6-t- (Butylphenol), 2,2'-methylenebis (4-methyl-6-tert-butylphenol), N-nitroso-N-phenylhydroxylamine aluminum salt are preferred.
The addition amount of the thermal polymerization inhibitor is preferably about 0.01 to about 5% by mass with respect to the total solid content of the photosensitive layer.

<Higher fatty acid derivatives, etc.>
In order to prevent polymerization inhibition by oxygen, a higher fatty acid derivative such as behenic acid or behenamide is added to the photosensitive layer of the present invention so that it is unevenly distributed on the surface of the photosensitive layer during the drying process after coating. May be. The amount of the higher fatty acid derivative added is preferably from about 0.1 to about 10% by mass based on the total solid content of the photosensitive layer.

<Plasticizer>
The photosensitive layer of the present invention may contain a plasticizer. Examples of the plasticizer include phthalates such as dimethyl phthalate, diethyl phthalate, dibutyl phthalate, diisobutyl phthalate, dioctyl phthalate, octyl capryl phthalate, dicyclohexyl phthalate, ditridecyl phthalate, butyl benzyl phthalate, diisodecyl phthalate, diallyl phthalate; Glycol esters such as glycol phthalate, ethyl phthalyl ethyl glycolate, methyl phthalyl ethyl glycolate, butyl phthalyl butyl glycolate, triethylene glycol dicaprylate; Phosphate esters such as tricresyl phosphate and triphenyl phosphate Diisobutyl adipate, dioctyl adipate, dimethyl sebacate, dibutyl sebacate, dioct Ruazereto, aliphatic dibasic acid esters such as dibutyl maleate; polyglycidyl methacrylate, triethyl citrate, glycerin triacetyl ester, butyl laurate in. The plasticizer content is preferably about 30% by mass or less based on the total solid content of the photosensitive layer.

<Inorganic fine particles>
The photosensitive layer of the present invention may contain inorganic fine particles in order to improve the strength of the cured film in the image area. As the inorganic fine particles, for example, silica, alumina, magnesium oxide, titanium oxide, magnesium carbonate, calcium alginate, or a mixture thereof is preferably exemplified. Even if they are not photothermally convertible, they can be used for strengthening the film, enhancing interfacial adhesion by surface roughening, and the like. The inorganic fine particles preferably have an average particle size of 5 nm to 10 μm, and more preferably 0.5 to 3 μm. Within the above range, it is possible to form a non-image portion having excellent hydrophilicity, which is stably dispersed in the photosensitive layer, sufficiently retains the film strength of the photosensitive layer, and hardly causes stains during printing.
The inorganic fine particles as described above can be easily obtained as a commercial product such as a colloidal silica dispersion.
The content of the inorganic fine particles is preferably 20% by mass or less, and more preferably 10% by mass or less, based on the total solid content of the photosensitive layer.

<Low molecular hydrophilic compound>
The photosensitive layer of the present invention can contain a hydrophilic low molecular weight compound for improving developability. Examples of the hydrophilic low-molecular compound include water-soluble organic compounds such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol and the like, and ether or ester derivatives thereof, glycerin, Polyhydroxys such as pentaerythritol, organic amines such as triethanolamine and diethanolamine monoethanolamine and salts thereof, organic sulfonic acids such as toluenesulfonic acid and benzenesulfonic acid and salts thereof, organic phosphonic acids such as phenylphosphonic acid and the like Organic carboxylic acids such as salts, tartaric acid, oxalic acid, citric acid, malic acid, lactic acid, gluconic acid, amino acids and their salts, and organic quaternary amines such as tetraethylamine hydrochloride Salt, and the like.

<Formation of photosensitive layer>
The photosensitive layer of the present invention is formed by preparing or applying a coating solution by dispersing or dissolving the necessary components described above in a solvent. Solvents used here include ethylene dichloride, cyclohexanone, methyl ethyl ketone, methanol, ethanol, propanol, ethylene glycol monomethyl ether, 1-methoxy-2-propanol, 2-methoxyethyl acetate, 1-methoxy-2-propyl acetate, dimethoxy Examples include ethane, methyl lactate, ethyl lactate, N, N-dimethylacetamide, N, N-dimethylformamide, tetramethylurea, N-methylpyrrolidone, dimethyl sulfoxide, sulfolane, γ-butyllactone, toluene, water, and the like. However, the present invention is not limited to this. These solvents are used alone or in combination. The solid content concentration of the coating solution is preferably 1 to 50% by mass.
The photosensitive layer of the present invention can be formed by preparing a plurality of coating solutions in which the same or different components are dispersed or dissolved in the same or different solvents, and repeatedly applying and drying a plurality of times.

The coating, the photosensitive layer coating amount on the support obtained after drying (solid content) may be varied according to the intended purpose, generally 0.3 to 3.0 g / m ² is preferred. Within this range, good sensitivity and good film properties of the photosensitive layer can be obtained.
Various methods can be used as the coating method. Examples thereof include bar coater coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating, and roll coating.

<Protective layer>
In the lithographic printing plate precursor according to the invention, a protective layer (oxygen blocking layer) is preferably provided on the photosensitive layer in order to block diffusion and penetration of oxygen that hinders the polymerization reaction during exposure. The protective layer used in the present invention has an oxygen permeability A of 1.0 ≦ A ≦ 20 (mL / m ² · day) at 25 ° C. and 1 atm.
) Is preferable. If the oxygen permeability A is less than 1.0 (mL / m ² · day), an unnecessary polymerization reaction may occur during production and raw storage, and unnecessary fogging and image lines may occur during image exposure. This causes the problem of fatness. Conversely, when the oxygen permeability A exceeds 20 (mL / m ² · day) and is too high, the sensitivity is lowered. The oxygen permeability A is more preferably 1.5 ≦ A ≦ 12 (mL / m ² · day), and further preferably 2.0 ≦ A ≦ 10.0 (
mL / m ² · day). In addition to the oxygen permeability described above, the properties desired for the protective layer further do not substantially impede the transmission of light used for exposure, have excellent adhesion to the photosensitive layer, and are easy in the development process after exposure. It is desirable that it can be removed. The device concerning such a protective layer has been conventionally made, and is described in detail in US Pat. No. 3,458,311 and JP-B-55-49729.

  As a material that can be used for the protective layer, for example, a water-soluble polymer compound having relatively excellent crystallinity is preferably used. Specifically, polyvinyl alcohol, vinyl alcohol / vinyl phthalate copolymer, vinyl acetate / vinyl are used. Examples include water-soluble polymers such as alcohol / vinyl phthalate copolymer, vinyl acetate / crotonic acid copolymer, polyvinyl pyrrolidone, acidic celluloses, gelatin, gum arabic, polyacrylic acid, and polyacrylamide. Or they can be mixed. Of these, the use of polyvinyl alcohol as the main component gives the best results in terms of basic properties such as oxygen barrier properties and development removability.

  The polyvinyl alcohol used for the protective layer may be partially substituted with an ester, an ether, and an acetal as long as it contains an unsubstituted vinyl alcohol unit for having necessary oxygen barrier properties and water solubility. Similarly, some of them may have other copolymer components. Specific examples of polyvinyl alcohol include those that are hydrolyzed by 71 to 100 mol% and have a polymerization repeating unit in the range of 300 to 2400. 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 and the like, and these can be used alone or in combination. In a preferred embodiment, the content of polyvinyl alcohol in the protective layer is 20 to 95% by mass, and more preferably 30 to 90% by mass.

  Moreover, well-known modified polyvinyl alcohol can also be used preferably. For example, various hydrophilic modification sites such as anion modification sites modified with anions such as carboxyl groups and sulfo groups, cation modification sites modified with cations such as amino groups and ammonium groups, silanol modification sites, and thiol modification sites are randomly selected. Polyvinyl alcohol having various degrees of polymerization, the anion-modified site, the cation-modified site, the silanol-modified site, the thiol-modified site, the alkoxyl-modified site, the sulfide-modified site, and the ester modification of vinyl alcohol and various organic acids. Examples thereof include polyvinyl alcohol having various polymerization degrees having various modified sites such as a site, an ester-modified site of the anion-modified site and alcohols, an epoxy-modified site, and the like.

  As a component used by mixing with polyvinyl alcohol, polyvinyl pyrrolidone or a modified product thereof is preferable from the viewpoint of oxygen barrier properties and development removability, and the content in the protective layer is 3.5 to 80% by mass, preferably 10 to 60%. It is 15 mass%, More preferably, it is 15-30 mass%.

  Components of the protective layer (selection of PVA, use of additives), coating amount, and the like are selected in consideration of fogging, adhesion, and scratch resistance in addition to oxygen barrier properties and development removability. In general, the higher the hydrolysis rate of the PVA used (the higher the content of the unsubstituted vinyl alcohol unit in the protective layer), the thicker the film thickness, the higher the oxygen barrier property, which is advantageous in terms of sensitivity. The molecular weight of the (co) polymer such as polyvinyl alcohol (PVA) can be in the range of 2000 to 10 million, preferably in the range of 20,000 to 3 million.

  As another composition of the protective layer, glycerin, dipropylene glycol and the like can be added in an amount corresponding to several mass% with respect to the (co) polymer to provide flexibility. Anionic surfactants such as sodium acid salts; amphoteric surfactants such as alkylaminocarboxylates and alkylaminodicarboxylates; nonionic surfactants such as polyoxyethylene alkylphenyl ethers to the (co) polymer Mass% can be added.

  In addition, adhesion to the image area and scratch resistance are extremely important in handling the plate. That is, when a hydrophilic layer made of a water-soluble polymer is laminated on an oleophilic photosensitive layer, film peeling due to insufficient adhesion tends to occur, and the peeled part causes defects such as poor film hardening due to inhibition of oxygen polymerization. On the other hand, various proposals have been made to improve the adhesion between these two layers. For example, in U.S. Patent Application No. 292,501 and U.S. Patent Application No. 44,563, an acrylic emulsion or a water-insoluble vinyl pyrrolidone-vinyl acetate copolymer is contained in a hydrophilic polymer mainly composed of polyvinyl alcohol. It is described that sufficient adhesiveness can be obtained by mixing 20 to 60% by mass and laminating on a photosensitive layer. Any of these known techniques can be applied to the protective layer in the present invention. Such a coating method for the protective layer is described in detail in, for example, US Pat. No. 3,458,311 and Japanese Patent Publication No. 55-49729.

Furthermore, the protective layer in the lithographic printing plate precursor according to the invention preferably contains an inorganic stratiform compound for the purpose of improving oxygen barrier properties and photosensitive layer surface protection.
Here, the inorganic layered compound is a particle having a thin plate-like shape. For example, the following general formula A (B, C) _2-5 D ₄ O ₁₀ (OH, F, O) ₂
[However, A is any of K, Na, and Ca, B and C are any of Fe (II), Fe (III), Mn, Al, Mg, and V, and D is Si or Al. And mica groups such as natural mica and synthetic mica, talc, teniolite, montmorillonite, saponite, hectorite, zirconium phosphate and the like represented by the formula 3MgO.4SiO.H ₂ O.

In the mica group, natural mica includes muscovite, soda mica, phlogopite, biotite, and sericite. As the synthetic mica, fluorine phlogopite KMg ₃ (AlSi ₃ O ₁₀
) F ₂ , Potassium tetrasilicon mica KMg _2.5 Si ₄ O ₁₀ ) Non-swelling mica such as F ₂ , and Na tetrasilica mica NaMg _2.5 (Si ₄ O ₁₀ ) F ₂ , Na or Li teniolite (N
_{a, Li) Mg 2 Li (} Si 4 O 10) F 2, montmorillonite of Na or Li hectorite _{(Na, Li) 1/8 Mg 2} /5 Li 1/8 (Si 4 O 10) F 2 , etc. Examples include swelling mica. Synthetic smectite is also useful.

In the present invention, among the inorganic layered compounds, fluorine-based swellable mica, which is a synthetic inorganic layered compound, is particularly useful. That is, this swellable synthetic mica and swellable viscosity minerals such as montmorillonite, saponite, hectorite, bentonite, etc. have a laminated structure composed of unit crystal lattice layers with a thickness of about 10 to 15 mm, Atomic substitution is significantly greater than other viscous minerals. As a result, the lattice layer is deficient in positive charges, and cations such as Na ⁺ , Ca ²⁺ and Mg ²⁺ are adsorbed between the layers in order to compensate for this. The cations present between these layers are called exchangeable cations and exchange with various cations. In particular, when the cation between the layers is Li ⁺ or Na ⁺ , the bond between the layered crystal lattices is weak because the ionic radius is small, and the layer swells greatly with water. If shear is applied in this state, it will easily cleave and form a stable sol in water. Bentonite and swellable synthetic mica have this tendency and are useful in the present invention, and swellable synthetic mica is particularly preferably used.

  As the shape of the inorganic layered compound used in the present invention, from the viewpoint of diffusion control, the smaller the thickness, the better. The plane size is as long as it does not hinder the smoothness of the coated surface or the transmittance of actinic rays. Larger is better. Accordingly, the aspect ratio is 20 or more, preferably 100 or more, particularly preferably 200 or more. The aspect ratio is the ratio of the thickness to the major axis of the particle, and can be measured, for example, from a projected view of the particle by a micrograph. The larger the aspect ratio, the greater the effect that can be obtained.

  As for the particle diameter of the inorganic stratiform compound used in the present invention, the average major axis is 0.3 to 20 μm, preferably 0.5 to 10 μm, particularly preferably 1 to 5 μm. The average thickness of the particles is 0.1 μm or less, preferably 0.05 μm or less, particularly preferably 0.01 μm or less. For example, among inorganic layered compounds, the size of the swellable synthetic mica that is a representative compound is about 1 to 50 nm in thickness and about 1 to 20 μm in surface size.

  When the inorganic layered compound particles having such a large aspect ratio are contained in the protective layer, the coating film strength is improved, and the permeation of oxygen and moisture can be effectively prevented. Deterioration is prevented, and even when stored for a long time under high-humidity conditions, the storage stability of the planographic printing plate precursor does not deteriorate due to changes in humidity, and the storage stability is excellent.

It is preferable that content of the inorganic stratiform compound in a protective layer is 5/1-1/100 by mass ratio with respect to the quantity of the binder used for a protective layer. Even when a plurality of types of inorganic layered compounds are used in combination, the total amount of these inorganic layered compounds is preferably the above-described mass ratio.

  Next, an example of a general dispersion method of the inorganic stratiform compound used for the protective layer will be described. First, 5 to 10 parts by mass of the swellable layered compound mentioned above as a preferred inorganic layered compound is added to 100 parts by mass of water, and the mixture is thoroughly swelled and swollen, and then dispersed by a disperser. Examples of the disperser used here include various mills that disperse mechanically by applying a direct force, a high-speed stirring disperser having a large shearing force, and a disperser that provides high-intensity ultrasonic energy. Specifically, ball mill, sand grinder mill, visco mill, colloid mill, homogenizer, tisol bar, polytron, homomixer, homo blender, ketdy mill, jet agitator, capillary emulsifier, liquid siren, electrostrictive ultrasonic generator, An emulsifying device having a Paulman whistle can be used. A dispersion of 5 to 10% by mass of the inorganic stratiform compound dispersed by the above method is highly viscous or gelled and has very good storage stability. When preparing a protective layer coating solution using this dispersion, it is preferably prepared by diluting with water and stirring sufficiently, and then blending with a binder solution.

  In addition to the inorganic layered compound, known additives such as a surfactant for improving the coating property and a water-soluble plasticizer for improving the physical properties of the film can be added to the protective layer coating solution. Examples of the water-soluble plasticizer include propionamide, cyclohexanediol, glycerin, sorbitol and the like. A water-soluble (meth) acrylic polymer can also be added. Furthermore, known additives for improving the adhesion to the photosensitive layer and the temporal stability of the coating solution may be added to the coating solution.

  The protective layer coating solution thus prepared is applied onto the photosensitive layer provided on the support and dried to form a protective layer. The coating solvent can be appropriately selected in relation to the binder, but when a water-soluble polymer is used, it is preferable to use distilled water or purified water. The method for applying the protective layer is not particularly limited, and a known method such as the method described in US Pat. No. 3,458,311 or Japanese Patent Publication No. 55-49729 can be applied. . Specific examples of the protective layer include blade coating, air knife coating, gravure coating, roll coating coating, spray coating, dip coating, and bar coating.

The coating amount of the protective layer is preferably in the range of 0.05 to 10 g / m ^{2 in} terms of the coating amount after drying. When the inorganic layered compound is contained, 0.1 to 0.5 g / The range of m ² is more preferable, and when the inorganic layered compound is not contained, the range of 0.5 to 5 g / m ² is more preferable.

[Support]
The support used in the lithographic printing plate precursor according to the invention is not particularly limited as long as it is a dimensionally stable plate-like hydrophilic support. For example, paper, paper laminated with plastic (eg, polyethylene, polypropylene, polystyrene, etc.), metal plate (eg, aluminum, zinc, copper, etc.), plastic film (eg, cellulose diacetate, cellulose triacetate, cellulose propionate) Cellulose butyrate, cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, etc.), and paper or plastic films on which the above-mentioned metals are laminated or deposited. Preferable supports include a polyester film and an aluminum plate. Among these, an aluminum plate that has good dimensional stability and is relatively inexpensive is preferable.

The aluminum plate is a pure aluminum plate, an alloy plate containing aluminum as a main component and containing a trace amount of foreign elements, or a plastic laminated on a thin film of aluminum or an aluminum alloy. Examples of foreign elements contained in the aluminum alloy include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel, and titanium. The content of foreign elements in the alloy is preferably 10% by mass or less. In the present invention, a pure aluminum plate is preferable, but completely pure aluminum is difficult to manufacture in terms of refining technology, and therefore may contain a slightly different element. The composition of the aluminum plate is not specified, and a publicly known material can be used as appropriate.

  The thickness of the support is preferably from 0.1 to 0.6 mm, more preferably from 0.15 to 0.4 mm, and even more preferably from 0.2 to 0.3 mm.

  Prior to using the aluminum plate, it is preferable to perform a surface treatment such as roughening treatment or anodizing treatment. By the surface treatment, it becomes easy to improve hydrophilicity and secure adhesion between the photosensitive layer and the support. Prior to roughening the aluminum plate, a degreasing treatment with a surfactant, an organic solvent, an alkaline aqueous solution or the like for removing rolling oil on the surface is performed as desired.

The surface roughening treatment of the aluminum plate is performed by various methods. For example, mechanical surface roughening treatment, electrochemical surface roughening treatment (surface roughening treatment for dissolving the surface electrochemically), chemical treatment, etc. Surface roughening treatment (roughening treatment that chemically selectively dissolves the surface).
As a method for the mechanical surface roughening treatment, a known method such as a ball polishing method, a brush polishing method, a blast polishing method, or a buff polishing method can be used.
Examples of the electrochemical surface roughening treatment include a method in which an alternating current or a direct current is used in an electrolytic solution containing an acid such as hydrochloric acid or nitric acid. Another example is a method using a mixed acid as described in JP-A-54-63902.

  The surface-roughened aluminum plate is subjected to an alkali etching treatment using an aqueous solution of potassium hydroxide, sodium hydroxide or the like, if necessary, further neutralized, and if desired, wear resistant. In order to increase the anodic oxidation treatment.

As the electrolyte used for the anodizing treatment of the aluminum plate, various electrolytes that form a porous oxide film can be used. In general, sulfuric acid, hydrochloric acid, oxalic acid, chromic acid or a mixed acid thereof is used. The concentration of these electrolytes is appropriately determined depending on the type of electrolyte.
The conditions for anodizing treatment vary depending on the electrolyte used, and thus cannot be specified in general. d m ² , voltage 1 to 100 V, and electrolysis time 10 seconds to 5 minutes are preferable. The amount of the anodized film formed is preferably from 1.0 to 5.0 g / m ^2, and more preferably 1.5 to 4.0 g / m ^2. Within this range, good printing durability and good scratch resistance of the non-image area of the lithographic printing plate can be obtained.

  As the support used in the present invention, the substrate having the above-mentioned surface treatment and having an anodized film may be used as it is, but for further improvement in adhesion to the upper layer, hydrophilicity, resistance to contamination, heat insulation and the like. If necessary, it contains a micropore enlargement treatment, a micropore sealing treatment, and a hydrophilic compound described in Japanese Patent Application Laid-Open Nos. 2001-253181 and 2001-322365. A surface hydrophilization treatment immersed in an aqueous solution can be selected as appropriate. Of course, these enlargement processing and sealing processing are not limited to those described above, and any conventionally known method can be performed.

Sealing treatment includes vapor sealing, single treatment with zirconic fluoride, treatment with an aqueous solution containing an inorganic fluorine compound such as treatment with sodium fluoride, vapor sealing with addition of lithium chloride, sealing with hot water. Hole processing is also possible.
Of these, sealing treatment with an aqueous solution containing an inorganic fluorine compound, sealing treatment with water vapor, and sealing treatment with hot water are preferable.

  The hydrophilization treatment is described in the specifications of US Pat. Nos. 2,714,066, 3,181,461, 3,280,734, and 3,902,734. There are such alkali metal silicate methods. In this method, the support is immersed in an aqueous solution such as sodium silicate or electrolytically treated. In addition, the treatment with potassium zirconate fluoride described in JP-B 36-22063, U.S. Pat. Nos. 3,276,868, 4,153,461 and 4,689, And a method of treating with polyvinylphosphonic acid as described in the specification of No. 272.

  When using a support with insufficient surface hydrophilicity such as a polyester film as the support of the present invention, it is desirable to apply a hydrophilic layer to make the surface hydrophilic. As the hydrophilic layer, at least one element selected from beryllium, magnesium, aluminum, silicon, titanium, boron, germanium, tin, zirconium, iron, vanadium, antimony, and a transition metal described in JP-A-2001-199175 A hydrophilic layer formed by coating a coating solution containing a colloid of oxide or hydroxide, or organic hydrophilicity obtained by crosslinking or pseudo-crosslinking an organic hydrophilic polymer described in JP-A-2002-79772 A hydrophilic layer having a hydrophilic matrix, a hydrophilic layer having an inorganic hydrophilic matrix obtained by sol-gel conversion comprising hydrolysis, condensation reaction of polyalkoxysilane, titanate, zirconate or aluminate, or a metal oxide A hydrophilic layer made of an inorganic thin film having a surface is preferred. Arbitrariness. Among these, a hydrophilic layer formed by applying a coating solution containing a silicon oxide or a hydroxide colloid is preferable.

  Moreover, when using a polyester film etc. as a support body of this invention, it is preferable to provide an antistatic layer in the hydrophilic layer side of a support body, the opposite side, or both sides. In the case where the antistatic layer is provided between the support and the hydrophilic layer, it also contributes to improving the adhesion with the hydrophilic layer. As the antistatic layer, a polymer layer in which metal oxide fine particles or a matting agent are dispersed as described in JP-A-2002-79772 can be used.

The support preferably has a center line average roughness of 0.10 to 1.2 μm. Within this range, good adhesion to the photosensitive layer, good printing durability and good stain resistance can be obtained.
The color density of the support is preferably 0.15 to 0.65 as the reflection density value. Within this range, good image formability by preventing halation during image exposure and good plate inspection after development can be obtained.

(Undercoat layer)
In the lithographic printing plate precursor according to the invention, it is preferable to provide an undercoat layer of a compound containing a polymerizable group on a support. When an undercoat layer is used, the photosensitive layer is provided on the undercoat layer. The undercoat layer reinforces the adhesion between the support and the photosensitive layer in the exposed area, and easily peels the photosensitive layer from the support in the unexposed area, thereby improving developability.
As the undercoat layer, specifically, a silane coupling agent having an addition-polymerizable ethylenic double bond reactive group described in JP-A-10-282679, JP-A-2-304441. The phosphorus compound etc. which have the ethylenic double bond reactive group of description are mentioned suitably. Particularly preferable compounds include compounds having a polymerizable group such as a methacryl group or an allyl group and a support adsorbing group such as a sulfonic acid group, a phosphoric acid group, or a phosphoric acid ester. A compound having a hydrophilicity-imparting group such as an ethylene oxide group in addition to the polymerizable group and the support-adsorbing group can also be exemplified as a suitable compound.
The coating amount (solid content) of the undercoat layer is preferably 0.1 to 100 mg / m ² ,
More preferably, it is 30 mg / m ² .

[Back coat layer]
After the surface treatment is performed on the support or after the undercoat layer is formed, a back coat can be provided on the back surface of the support, if necessary.
Examples of the back coat include hydrolysis and polycondensation of an organic polymer compound described in JP-A-5-45885, an organometallic compound or an inorganic metal compound described in JP-A-6-35174. A coating layer made of a metal oxide obtained in this way is preferred. Among them, it is inexpensive to use a silicon alkoxy compound such as Si (OCH ₃ ) ₄ , Si (OC ₂ H ₅ ) ₄ , Si (OC ₃ H ₇ ) ₄ , Si (OC ₄ H ₉ ) _4. It is preferable in terms of easy availability.

[Plate making method]
After the lithographic printing plate precursor in the present invention is image-exposed with a light source, the protective layer and the non-exposed photosensitive layer can be removed at once by an automatic developing machine in the presence of a developer to form an image on the support surface. .
In addition, such processing in an automatic developing machine has an advantage of being freed from dealing with development residue derived from a protective layer / photosensitive layer that occurs in the case of on-press development.

The developer used in the present invention may be an aqueous solution having a pH of 2 to 14, but it is preferably an aqueous solution having a pH of 2 to 10 because it has little influence on workers and the environment. As the aqueous solution having a pH of 2 to 10, for example, water alone or an aqueous solution containing water as a main component (containing 60% by mass or more of water) is preferable, and in particular, an aqueous solution having the same composition as a generally known fountain solution, An aqueous solution containing a surfactant (anionic, nonionic, cationic, etc.) or an aqueous solution containing a water-soluble polymer compound is preferred. In particular, an aqueous solution containing both a surfactant and a water-soluble polymer compound is preferable. The pH of the developer is more preferably 3-8, and even more preferably 4-7.
When an acidic to neutral developer is used, it is preferable to contain either an organic acid or an inorganic acid. By containing an organic acid or an inorganic acid, developability can be improved during plate making, and it is possible to suppress the occurrence of stains in the non-image area of the plate that has been made.

  Examples of the anionic surfactant used in the present invention include fatty acid salts, abietic acid salts, hydroxyalkane sulfonic acid salts, alkane sulfonic acid salts, dialkyl sulfosuccinic acid salts, linear alkyl benzene sulfonic acid salts, branched alkyl benzene sulfonic acid salts, Alkylnaphthalene 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 compounds Glyceryl sulfate ester 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 -Partial saponifications of maleic anhydride copolymer, partial saponifications of olefin-maleic anhydride copolymer, naphthalene sulfonate formalin condensate and the like. Among these, dialkyl sulfosuccinates, alkyl sulfate esters and alkyl naphthalene sulfonates are particularly preferably used.

It does not specifically limit as a cationic surfactant used for this invention, A conventionally well-known thing can be used. Examples thereof include alkylamine salts, quaternary ammonium salts, polyoxyethylene alkylamine salts, and polyethylene polyamine derivatives.

Nonionic surfactants used in the present invention 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 amide ethylene oxide adduct, fat and oil ethylene oxide adduct, polypropylene glycol ethylene oxide adduct, dimethylsiloxane-ethylene oxide block copolymer, dimethylsiloxane- (propylene oxide-ethylene oxide) block copolymer, etc. Fatty acid ester of alcohol type glycerol, fatty acid ester of pentaerythritol, sorbitol and sorbita Fatty acid esters of fatty acid esters of sucrose, alkyl ethers of polyhydric alcohols, fatty acid amides of alkanolamines.
These nonionic surfactants may be used alone or in combination of two or more. In the present invention, ethylene oxide adduct of sorbitol and / or sorbitan fatty acid ester, polypropylene glycol ethylene oxide adduct, dimethylsiloxane-ethylene oxide block copolymer, dimethylsiloxane- (propylene oxide-ethylene oxide) block copolymer, polyhydric alcohol Fatty acid esters are more preferred.

Further, from the viewpoint of stable solubility or turbidity in water, the nonionic surfactant used in the developer of the present invention is HLB (Hydrophile-Lipophile).
The (Balance) value is preferably 6 or more, and more preferably 8 or more. Furthermore, the ratio of the nonionic surfactant contained in the developer is preferably 0.01 to 10% by mass, and more preferably 0.01 to 5% by mass.
Also, acetylene glycol-based and acetylene alcohol-based oxyethylene adducts, fluorine-based and silicon-based surfactants can be used in the same manner.
As the surfactant used in the developer of the present invention, a nonionic surfactant is particularly suitable from the viewpoint of foam suppression.

  Examples of the water-soluble polymer compound used in the developer of the present invention include soybean polysaccharide, modified starch, gum arabic, dextrin, fibrin derivatives (eg, carboxymethylcellulose, carboxyethylcellulose, methylcellulose, etc.) and modified products thereof, pullulan. , Polyvinyl alcohol and its derivatives, polyvinyl pyrrolidone, polyacrylamide and acrylamide copolymer, vinyl methyl ether / maleic anhydride copolymer, vinyl acetate / maleic anhydride copolymer, styrene / maleic anhydride copolymer, etc. It is done.

  A well-known thing can be used for the said soybean polysaccharide, for example, there exists a brand name Soya Five (made by Fuji Oil Co., Ltd.) as a commercial item, and the thing of 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 the modified starch, known ones can be used, and starch such as corn, potato, tapioca, rice and wheat is decomposed with acid or enzyme in the range of 5 to 30 glucose residues per molecule, and further in an alkali. It can be made by a method of adding oxypropylene or the like.

Two or more water-soluble polymer compounds can be used in combination. The content of the water-soluble polymer compound in the developer is preferably from 0.1 to 20% by mass, more preferably from 0.5 to 10% by mass.

  Further, the developer of the present invention may contain an organic solvent. Examples of the organic solvent that can be contained include aliphatic hydrocarbons (hexane, heptane, “Isopar E, H, G” (manufactured by Esso Chemical Co., Ltd.) or gasoline, kerosene, etc.), and aromatic hydrocarbons (toluene). , Xylene, etc.), halogenated hydrocarbons (methylene dichloride, ethylene dichloride, tricrene, 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.).

  If the organic solvent is insoluble in water, it can be used after being solubilized in water using a surfactant or the like. If the developer contains an organic solvent, safety, ignition, From the viewpoint of property, the concentration of the solvent is preferably less than 40% by mass.

  In addition to the above, the developer of the present invention may contain a preservative, a chelate compound, an antifoaming agent, an organic acid, an inorganic acid, an inorganic salt, and the like.

  Preservatives include phenol or derivatives thereof, formalin, imidazole derivatives, sodium dehydroacetate, 4-isothiazolin-3-one derivatives, benzisothiazolin-3-one, benztriazole derivatives, amiding anidine derivatives, quaternary ammonium salts, pyridine, Derivatives such as quinoline and 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.

  Examples of chelate compounds 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, and 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.

As the antifoaming agent, a general silicon-based self-emulsifying type, emulsifying type, or nonionic surfactant having a HLB of 5 or less can be used. Silicon antifoaming agents are preferred.
Among them, emulsification dispersion type and solubilization can be used.

  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.

  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 developer described above can be used as a developer and developer replenisher for the exposed negative lithographic printing plate precursor, and is preferably applied to an automatic processor described later. When developing using an automatic processor, the developing solution becomes fatigued according to the amount of processing, so the processing capability may be restored using a replenisher or a fresh developer. This replenishing method is also preferably applied to the lithographic printing plate preparation method of the present invention.

  The development treatment with an aqueous solution having a pH of 2 to 10 in the present invention can be preferably carried out by an automatic processor equipped with a developer supply means and a rubbing member. As an automatic processor, for example, an automatic processor described in JP-A-2-220061 and JP-A-60-59351, which performs a rubbing process while transporting a lithographic printing plate precursor after image recording, or a cylinder Examples thereof include an automatic processor described in US Pat. Nos. 5,148,746, 5,568,768 and British Patent 2,297,719, which rub the lithographic printing plate precursor after image recording set thereon 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 that can be preferably 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, as described in Japanese Patent Application Laid-Open No. 58-159533, Japanese Patent Application Laid-Open No. 3-100554, or Japanese Utility Model Publication No. 62-167253, metal or plastic in which brush materials are implanted in rows. A brush roll in which the groove mold material is radially wound around a plastic or metal roll as a core without any gap can be used.
The brush material includes plastic fibers (for example, polyesters such as polyethylene terephthalate and polybutylene terephthalate, polyamides such as nylon 6.6 and nylon 6.10, polyacrylonitrile, poly (meth) acrylate, etc. Acrylic and polyolefin synthetic fibers such as polypropylene and polystyrene) can be used. For example, the fiber has a hair diameter of 20 to 400 μm and a hair length of 5 to 30 mm. Can be used.
Furthermore, the outer diameter of the rotating brush roll is preferably 30 to 200 mm, and the peripheral speed at the tip of the brush rubbing the plate surface is preferably 0.1 to 5 m / sec.
Moreover, it is preferable to use two or more rotating brush rolls.

The rotating direction of the rotating brush roll used in the present invention may be the same or opposite to the conveying direction of the planographic printing plate precursor of the present invention. As described above, when two or more rotating brush rolls are used, it is preferable that at least one rotating brush roll rotates in the same direction and at least one rotating brush roll rotates in the opposite direction. This further ensures the removal of the heat sensitive layer in the non-image area. Furthermore, it is also effective to swing the rotating brush roll in the direction of the rotation axis of the brush roll.

  Although the temperature of the developer can be used at any temperature, it is preferably 10 ° C to 50 ° C.

  In the present invention, the lithographic printing plate after the rubbing treatment can be optionally washed with water, dried and desensitized. In the desensitizing treatment, a known desensitizing solution can be used.

  In addition, as the plate-making process of the lithographic printing plate from the lithographic printing plate precursor according to the present invention, the entire surface may be heated before exposure, during exposure, and between exposure and development, if necessary. By such heating, the image forming reaction in the photosensitive layer is promoted, and advantages such as improvement in sensitivity and printing durability and stabilization of sensitivity may occur. Further, for the purpose of improving the image strength and printing durability, it is also effective to subject the developed image to full post heating or full exposure. Usually, the heating before development is preferably performed under a mild condition of 150 ° C. or less. If the temperature is too high, problems such as covering up to the non-image area occur. Very strong conditions are used for heating after development. Usually, it is the range of 200-500 degreeC. If the temperature is low, sufficient image strengthening action cannot be obtained. If the temperature is too high, problems such as deterioration of the support and thermal decomposition of the image area occur.

The plate making process will be further described in detail.
In the present invention, as described above, the development treatment may be performed immediately after the exposure step, but a heat treatment step may be provided between the exposure step and the development step. This heat treatment has the effect of improving the printing durability and further improving the uniformity of the image curing degree within the plate surface, and the conditions can be appropriately set within the range where these effects are present. Examples of the heating means include a conventional convection oven, an IR irradiation device, an IR laser, a microwave device, a Wisconsin oven, and the like. For example, it can be 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.
In the present invention, a development processing step is performed after the above-described exposure step and preferably the heat treatment step, to obtain a lithographic printing plate. The plate setter used in the exposure process, the heat treatment means used in the heat treatment, and the developing device used in the development process are preferably connected to each other and automatically continuously processed. Specifically, it 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 means may be inserted between the plate setter and the developing device, and the heating means and the developing device may be integrated.

  When the printing plate to be used is easily affected by ambient light in the work environment, it is preferable that the plate making line is shielded by a filter or a cover.

After the image formation as described above, in the present invention, the photosensitive layer exposed portion remaining on the surface of the lithographic printing plate is covered with a liquid layer, and the entire surface is exposed with light having a wavelength causing radical polymerization (post-exposure). It is characterized by performing.
Hereinafter, the post-exposure in the present invention will be described.
A first embodiment relating to a post-exposure method and apparatus usable in the present invention will be described with reference to FIGS.

  In the post-exposure apparatus shown in FIG. 2 and FIG. 3, in order to perform post-exposure processing on a transport path for transporting the lithographic printing plate 10 in the atmosphere, a transport roller 12 that is a pair of nip rollers at each predetermined position before and after the post-exposure position, 14 is arranged.

  Each of the transport rollers 12 and 14 is rotationally driven by a motor or the like as a drive source (not shown) while the planographic printing plate 10 is sandwiched between the transport rollers 12 and 14. The planographic printing plate 10 is configured to be conveyed. These transport rollers 12 and 14 are both configured as free rollers, or only rollers that are in rolling contact with the surface of the planographic printing plate 10 are configured as free rollers. In addition to these, the planographic printing plate 10 is transported. A nip roller that is rotationally driven by a drive source for this purpose may be mounted.

  The post-exposure position set between the two sets of transport rollers 12 and 14 has a predetermined distance from the surface on the image recording layer side of the transported lithographic printing plate 10 (here, set to approximately 1 mm to approximately 3 mm). An exposure assisting member 16 configured as a transparent member is disposed at a position where a gap is placed. Here, as a result of actual experiments, as described later, when water is supplied onto the lithographic printing plate 10 by the liquid shower bar 26 as a liquid supply means, the end portion of the lithographic printing plate 10 is caused by the action of the surface tension of the water. It was confirmed that a water layer having a thickness of about 1 mm to about 3 mm spread on the surface of the lithographic printing plate 10 on the average was formed.

  Therefore, in this post-exposure apparatus, since only a water layer is formed between the planographic printing plate 10 and the bottom surface of the exposure assisting member 16 so that air does not enter, the liquid shower bar 26 as a liquid supply means is used. When the amount of water supplied is adjusted so that the thickness of the water layer on the planographic printing plate 10 is controlled to be a predetermined thickness, a distance equal to the predetermined thickness of the controlled water layer or The distance between the planographic printing plate 10 and the bottom surface of the exposure assisting member 16 is set so as to be shorter than this.

  The exposure assisting member 16 is formed by forming a material such as transparent glass or plastic having a plane of an incident surface and an exit surface (bottom surface) of a laser beam into a rectangular plate shape (cuboid shape). In addition, you may comprise this exposure assistance member 16 so that it may have a function as a lens.

  In this post-exposure apparatus, even if the surface of the water layer on the planographic printing plate 10 is uneven by using the exposure assisting member 16 configured as described above, the surface of the water layer is exposed. The auxiliary member 16 covers and the surface of the water layer can be planarized. Further, since the surface of the exposure assisting member 16 is flat, it is preferable to irradiate the light incident on the surface on the image recording layer of the planographic printing plate 10 on average so that partial deviation of the light amount does not occur. Can be post-exposure processed.

  In this post-exposure apparatus, a post-exposure light irradiation means 20 is provided in order to perform post-exposure processing via the exposure auxiliary member 16. For example, the light irradiation means 20 emits light having a wavelength for photosensitivity (light having a predetermined wavelength such as infrared light, visible light, or ultraviolet light) suitable for causing a radical polymerization reaction in the photosensitive layer of the planographic printing plate 10. A plurality of light emitting diodes (LEDs, here, ultraviolet LEDs that emit ultraviolet light) 20A are configured by an LED array light source, which is a light source that is configured to be arranged at a high density such as a staggered pattern. .

  In this post-exposure apparatus, each LED 20A is installed so as to be embedded in the upper surface portion of the exposure assisting member 16, as shown in FIGS. The LED array light source provided with a plurality of LEDs 20A may be configured separately from the exposure assisting member 16.

  The light irradiating means 20 may be composed of an electroluminescence (EL) element that is a surface light source that emits light having a photosensitive wavelength.

  In this post-exposure apparatus, a liquid shower bar 26 as a liquid supply means is disposed in a predetermined direction between the exposure auxiliary member 16 in the conveyance path and the conveyance rollers 12 and 14 disposed on the upstream side in the conveyance direction. The lithographic printing plate 10 is disposed so as to correspond to a range over the entire width direction of the planographic printing plate 10 in a direction orthogonal to the horizontal direction.

  The liquid shower bar 26 is formed in, for example, a cylindrical shape, and a large number of nozzle holes are arranged in a row at equal intervals on the peripheral side face toward the planographic printing plate 10 and supplied to the inside of the liquid shower bar 26. The liquid (here, water) is ejected from each nozzle to form a substantially uniform thin film-like liquid layer on the surface of the planographic printing plate 10. The liquid sprayed from the liquid shower bar 26 and supplied onto the lithographic printing plate 10 spreads so as to wet the surface of the lithographic printing plate 10, and is a substantially uniform thin film-like liquid layer due to the surface tension of the liquid. make. At this time, in the post-exposure apparatus, as described above, the amount of water supplied by the liquid shower bar 26 is adjusted, and the thickness of the water layer on the planographic printing plate 10 is controlled to be a predetermined thickness.

  Thus, the substantially uniform thin film-like liquid layer formed on the lithographic printing plate 10 is conveyed together with the lithographic printing plate 10 to reach the position of the exposure auxiliary member 16, and the exposure auxiliary member 16 and the lithographic printing plate 10. To fill the gap between the exposure auxiliary member 16 and the planographic printing plate 10 without causing air bubbles to remain in the gap between the exposure assisting member 16 and the lithographic printing plate 10 to create an oxygen-blocking state for exposure processing.

As the liquid used here, a solution which can transmit a light beam for post-exposure of the lithographic printing plate 10 and is inert to the lithographic printing plate 10 and does not wet the lithographic printing plate 10 can be used. Here, although normal tap water is used, liquid paraffin, silicon oil, or the like can be used. Moreover, the developing solution used for a development process can also be used.
Preferably, water such as tap water and pure water, a developer used for development processing, an aqueous solution containing a water-soluble polymer compound that may be contained in the developer, and a surfactant that may be contained in the developer An aqueous solution containing In particular, an aqueous solution containing a water-soluble polymer compound is preferably used from the viewpoint of improving soiling after plate making. The water-soluble polymer compound is not particularly limited, but the compounds listed as the water-soluble polymer compound in the previous period are preferable, and gum arabic is particularly preferable.

  The substantially uniform thin film-like liquid layer formed on the lithographic printing plate 10 is transported together with the lithographic printing plate 10 to leave the position of the exposure auxiliary member 16, and is squeezed by the transport rollers 12 and 14 on the downstream side in the transport direction. Will be dropped.

  Thus, in order to receive the liquid squeezed down from the lithographic printing plate 10 or spilled from both sides of the lithographic printing plate 10, two sets of conveyance rollers 12 and 14 sandwiching the exposure position are arranged below the conveyance path. The tray member 28 is installed so as to cover a slightly larger range including the predetermined range.

  Further, a liquid circulation conduit 30 is installed between the tray member 28 and the liquid shower bar 26. A filter 34, a pump 36, and a heater 38 are disposed in the middle of the pipe member 32 constituting the series of liquid circulation pipes 30.

  The liquid circulation pipe 30 sends the liquid introduced from the liquid inlet opening on the bottom surface of the tray member 28 to the filter 34 through the pipe member 32 and then sends it to the pump 36. The pump 36 pressurizes the liquid sucked from the filter 34 side, sends it to the heater 38 and heats it to about 60 ° C. to 80 ° C. (may be less than the boiling point) and then supplies it to the liquid shower bar 26. A series of liquid circulation systems in which the nozzles 26 are ejected at a predetermined flow rate are configured.

  Thereafter, in the exposure apparatus, the photosensitive layer on which the image of the planographic printing plate 10 is formed is heated by supplying the heated liquid from the shower bar 26 to the entire surface of the planographic printing plate 10 and covering it with the liquid layer. The radical polymerization reaction can be promoted, and the entire image recording layer forming the image can be polymerized and cured to help improve the printing durability of the lithographic printing plate 10.

  Further, in this post-exposure apparatus, the back surface of the lithographic printing plate 10 is placed on the lower side (back side) of the lithographic printing plate 10, which is directly below the liquid receiving position where the liquid sprayed from the nozzle of the liquid shower bar 26 hits the lithographic printing plate 10. A guide roller 40 is mounted to prevent the liquid squirted from the nozzles from hitting the planographic printing plate 10 and causing vibrations by rolling and supporting the plate. That is, when this guide roller 40 is disposed, the post-exposure processing can be performed in a state where vibrations of the planographic printing plate 10 are suppressed when the liquid ejected from the nozzles of the liquid shower bar 26 is received. it can.

  Further, in this post-exposure apparatus, it was heated to about 100 ° C. in order to dry the surface of the lithographic printing plate 10 at a position close to the downstream side in the transport direction from the transport rollers 12 and 14 arranged on the downstream side in the transport direction. A dryer 39 for blowing hot air is disposed.

  In this post-exposure apparatus, the photosensitive layer forming this image is heated by spraying hot air heated from the dryer 39 on the entire surface of the photosensitive layer forming the image of the lithographic printing plate 10, thereby radical polymerization. The reaction can be promoted, and the entire photosensitive layer forming the image can be more reliably polymerized and cured to help improve the printing durability of the lithographic printing plate 10.

  As shown in FIG. 3, this post-exposure apparatus is provided with a lighting control means for lighting the LED 20A of the LED array light source as the light irradiation means 20 only when necessary for the post-exposure processing.

  Note that when the LED 20A is used as the light irradiation means 20 in the post-exposure device, the LED 20A emits light with a predetermined light amount immediately after the LED 20A is turned on. Unlike the light source, it is possible to control the lighting only when necessary for the post-exposure processing.

  Here, in the case of using another light source that requires a long standby time from energization to a predetermined light emission amount, a predetermined time is applied after energization from the time when the planographic printing plate 10 is carried into the exposure auxiliary member 16. Since it is necessary to turn on other light sources at a point in time before a long waiting time until the amount of light is emitted, it is difficult to control turning on and off frequently, and useless lighting regardless of post-exposure processing Time will increase.

  The lighting control means for the LED 20A as the light irradiating means 20 is a lithographic plate transported to a predetermined position on the transport path that is closer to the upstream side in the transport direction than the transport rollers 12 and 14 that are closest to the upstream side of the exposure auxiliary member 16 in the transport direction. A plate end detection sensor 21 configured to be able to detect the front end and the rear end in the transport direction of the printing plate 10 is disposed.

  The plate edge detection sensor 21 is constituted by, for example, a reflection type light detection sensor, receives the reflected light of the sensor light irradiated to the detection position on the conveyance path, and sends the value of the received light amount to the light source lighting control circuit 23. Send.

  The light source lighting control circuit 23 is configured to change the amount of reflected light for detection received by the plate end detection sensor 21 when the plate end of the planographic printing plate 10 passes the detection position on the conveyance path. It is determined that the plate edge has been detected. The light source lighting control circuit 23 determines that the plate edge of the planographic printing plate 10 has been detected when the amount of reflected light for detection reaches a predetermined light amount when reflected on the surface of the planographic printing plate 10. Anyway.

  Further, in the light source lighting control circuit 23, for example, when the plate end is detected for the first time after the lithographic printing plate 10 starts to be transported on the transport path, this is determined as the front end in the transport direction of the lithographic printing plate 10, and the second time. When the plate edge is detected, this is determined as the rear end in the transport direction of the planographic printing plate 10.

  When the light source lighting control circuit 23 detects the leading edge of the planographic printing plate 10 in the transport direction, it transmits an ON operation control signal to the LED light source power source 25 to light the LED 20A. In the control for turning on the LED 20A, the LED 20A is turned on immediately when the leading edge of the planographic printing plate 10 is detected. Alternatively, the light source lighting control circuit 23 is configured such that a predetermined waiting time for lighting until the leading end of the planographic printing plate 10 in the transport direction reaches immediately before the exposure assisting member 16 is measured with a timer, and the transport direction of the planographic printing plate 10 is measured. Control may be performed so that the LED 20A is turned on when a predetermined waiting time for lighting has elapsed since the tip was detected.

  Further, the light source lighting control circuit 23 detects a predetermined waiting time for turning off until the rear end in the transport direction of the planographic printing plate 10 finishes passing through the exposure auxiliary member 16 when the rear end in the transport direction of the planographic printing plate 10 is detected. Is controlled by a timer, and the LED 20A is controlled to be turned off when the predetermined standby time for turning off has elapsed.

  In this way, the lighting control means controls the LED 20A to be lit only when the lithographic printing plate 10 is subjected to the post-exposure processing, so that the energy of lighting the LED 20A when the post-exposure processing is not performed. It is possible to eliminate waste and to extend the period during which the LED 20A can be used in the post-exposure device (the service life of the LED 20A when used in the post-exposure device). That is, in this post-exposure device, the LED 20A is used in the post-exposure device because the time for which the LED 20A is lit can be shortened when the LED 20A is lit and turned off more frequently than when the LED 20A is continuously lit. The period that can be done can be lengthened.

  Moreover, when LED20A is used as the light irradiation means 20, LED20A does not generate | occur | produce an extra infrared ray, and uniform illumination with a long lifetime is attained.

  Next, the post-exposure operation of the lithographic printing plate in the lithographic printing plate post-exposure device according to the first embodiment configured as described above will be described.

  In this lithographic printing plate post-exposure apparatus, the developed lithographic printing plate 10 is carried into the post-exposure apparatus by a supply means (not shown).

  Then, the developed lithographic printing plate 10 carried into the post-exposure apparatus is carried between the pair of conveyance rollers 12 and 14 arranged on the upstream side of the conveyance path and conveyed, thereby the liquid shower bar 26. The liquid jetted from the nozzle is supplied onto the surface of the lithographic printing plate 10 to form a thin film of liquid on the surface of the lithographic printing plate 10.

  The planographic printing plate 10 is further conveyed and reaches a post-exposure position below the exposure auxiliary member 16. At this time, the LED 20A which is the light irradiation means 20 is turned on by the lighting control means. Further, the liquid layer on the lithographic printing plate 10 is pushed by the exposure assisting member 16 so that the liquid fills the gap space between the lithographic printing plate 10 and the exposure assisting member 16, and air bubbles, etc. Is assumed to be absent.

  In this post-exposure apparatus, while transporting the lithographic printing plate 10, from the LED array light source composed of a plurality of LEDs 20 </ b> A arranged in a staggered grid pattern, across the entire width of the lithographic printing plate 10 and in the transport direction By exposing a predetermined range having a predetermined length in a so-called surface exposure state, the entire surface of the lithographic printing plate 10 is post-exposed on average.

  In this post-exposure apparatus, the photosensitive layer of the planographic printing plate 10 is covered with liquid while the planographic printing plate 10 is transported from the post-exposure position where the auxiliary exposure member 16 is located to the positions of the transport rollers 12 and 14 on the downstream side in the transport direction. Since it is in a broken state and is kept from being shielded from oxygen in the air, the photosensitive layer is not affected by the inhibition of polymerization by oxygen, and the radical polymerization reaction is allowed to proceed without causing any photosensitivity to form an image. The entire layer can be polymerized and cured, and the printing durability of the lithographic printing plate 10 can be improved. In particular, this form of curing only the image area composed of the photosensitive layer exposed area is effective for a lithographic printing plate produced through a development process using an aqueous developer having a pH of 2 to 10.

  In this post-exposure apparatus, when the plate end detection sensor 21 detects the rear end in the transport direction of the planographic printing plate 10 under the control of the light source lighting control circuit 23, when a predetermined waiting time for light extinction has elapsed after the measurement by the timer. The LED 20A is turned off.

  As described above, the lithographic printing plate 10 subjected to the post-exposure processing at the post-exposure position where the exposure assisting member 16 is located is squeezed down by the transport rollers 12 and 14, and is supplied from the dryer 39 downstream in the transport direction. It is dried and transported by the hot air blown.

  In this post-exposure apparatus, a thin liquid is formed on the developed photosensitive layer of the planographic printing plate 10 only within a predetermined range before and after the post-exposure position with respect to the planographic printing plate 10 being transported on a transport path that transports in the atmosphere. Since the post-exposure is performed in a state where the liquid film is formed and the oxygen is blocked, the amount of liquid used for blocking oxygen during the post-exposure processing can be reduced to a minimum necessary amount.

  In this post-exposure apparatus, a small amount of liquid used to block oxygen during post-exposure processing is circulated while using the liquid circulation system filter 34 and the pump 36 while removing dust mixed into the liquid. Thus, it is possible to reliably perform oxygen post-exposure treatment on the portion necessary for the post-exposure processing of the planographic printing plate 10 with a very small amount of liquid.

  In this post-exposure apparatus, since the liquid from which dust has been removed by passing through the filter 34 of the liquid circulation system is supplied to the photosensitive layer of the planographic printing plate 10, a portion that is not post-exposed due to dust floating in the liquid is generated. Can be prevented.

  In this post-exposure apparatus, since the post-exposure light can be irradiated from above onto the planographic printing plate 10 that is transported with the photosensitive layer facing upward on the transport path that transports in the atmosphere, post-exposure processing can be performed. The LED array light source is disposed at a position higher than the liquid on the planographic printing plate 10 and the liquid shower bar 26 for flowing the liquid down, and even if there is liquid splash or liquid leakage, the LED array light source Can be prevented from getting wet with liquid.

  Next, a second embodiment relating to a post-exposure apparatus provided with an exposure tool for a lithographic printing plate according to the present invention will be described with reference to FIGS. In the post-exposure device for a lithographic printing plate according to the second embodiment, a means for supplying a liquid onto the lithographic printing plate 10 to the exposure auxiliary member 16 is integrally configured.

  In the post-exposure apparatus according to the second embodiment shown in FIG. 4, a pair of transport rollers 12 and 14 that are nip rollers are disposed before and after the post-exposure position on the transport path for transporting the planographic printing plate 10 in the atmosphere. At the same time, an exposure assisting member 16 provided with a liquid supply means, which is a tool used for post-exposure, is disposed on the exposure position of the transport path by a predetermined distance.

  The exposure assisting member 16 provided with the liquid supply means as the post-exposure tool is composed of a material such as transparent glass or plastic. For example, as shown in FIGS. 5 and 6, a rectangular member body 16A is used. And an end face side member 16B in the longitudinal direction, one end face member 16C in the short side direction, and a connecting end member 16D for connection to the tube member 32.

In the member main body 16A, a U-shaped liquid introduction groove 17A is formed in an end surface portion in the longitudinal direction corresponding to the upstream side in the transport direction. Further, in the member main body 16A, the end portion 17B corresponding to the side adjacent to the lithographic printing plate 10 side of the liquid guide groove 17A has a liquid projection amount larger than the end portion 17C corresponding to the side spaced apart from the lithographic printing plate 10 of the liquid guide groove 17A. It is formed so as to be shortened by the width of the supply opening.

  An end face formed in a rectangular parallelepiped having the same length as the longitudinal direction of the member main body 16A and the same width as the thickness of the member main body 16A is formed on the end portion 17C of the member main body 16A which is the side away from the planographic printing plate 10 of the liquid guide groove 17A. The side member 16B is fixed so as to be kept airtight.

  The end surface member 16B is fixed to one end portion in the longitudinal direction of the member main body 16A to which the end surface side member 16B is fixed so as to keep airtightness. Further, the connection end member 16D is fixed to the other end portion in the longitudinal direction of the member main body 16A fixed to the end surface side member 16B so as to keep airtightness.

  A pipe port portion of the pipe member 32 is fixed to the connection end member 16D. The connection end member 16D is configured so that the tube port of the tube member 32 having one end fixed to the connection end member 16D communicates with the liquid introduction groove 17A while being fixed to the member main body 16A.

  In the exposure assisting member 16 having the liquid supply means as the exposure tool configured as described above, the liquid introduction groove 17A communicating with the tube opening of the tube member 32 includes the end portion 17B of the member main body 16A and the end surface side member 16B. In combination with the liquid supply opening formed between the two, a liquid supply path communicating in a bowl shape is formed.

  The exposure assisting member 16, which is a tool used for subsequent exposure, transfers the liquid (here, water) fed from the tube member 32 from the liquid introduction channel 17A of the liquid supply path to the planographic printing plate 10 through the liquid supply opening. It has a function to let down an appropriate amount.

  As shown in FIG. 4, in the post-exposure device for a lithographic printing plate provided with the exposure assisting member 16 that is an instrument used for this post-exposure, a guide roller 40 is disposed below the conveyance path that is directly below the exposure assisting member 16. Thus, the lower surface of the planographic printing plate 10 is configured to be guided.

  In the post-exposure device for a lithographic printing plate provided with the tool used for post-exposure shown in FIG. 4, the lithographic printing plate 10 conveyed by the conveying rollers 12 and 14 and the guide roller 40 when performing the post-exposure processing. An appropriate amount of liquid is allowed to flow substantially uniformly over the entire length in the width direction of the planographic printing plate 10 from the liquid supply opening on the upstream side in the transport direction of the exposure assisting member 16.

  Then, the liquid flowing down from the liquid supply opening of the exposure assisting member 16 is filled between the photosensitive layer of the planographic printing plate 10 and the entire lower surface of the exposure assisting member 16 in combination with the transport operation of the planographic printing plate 10. And filled so that air bubbles do not enter. In the exposure auxiliary member 16 provided with the liquid supply means as an instrument used for the subsequent exposure, the liquid flows down from the liquid supply opening on the upstream side in the transport direction of the exposure auxiliary member 16, so that the liquid is immediately with the lithographic printing plate 10. Since it spreads between the entire lower surface of the exposure auxiliary member 16 and quickly fills, the liquid can be efficiently filled between the lithographic printing plate 10 and the exposure auxiliary member 16 with a relatively small amount of liquid, and The thickness of the liquid layer formed between the lithographic printing plate 10 and the exposure assisting member 16 can be relatively easily increased.

  At this time, the liquid supplied onto the planographic printing plate 10 is between the transport rollers 12 and 14 on the upstream side in the transport direction from the post-exposure position and the transport rollers 12 and 14 on the downstream side in the transport direction from the post-exposure position. It spreads to become a state where it accumulates in a layered state due to surface tension.

In this lithographic printing plate post-exposure apparatus, the light irradiation means 20 is conveyed while conveying the lithographic printing plate 10 by the conveying rollers 12 and 14 in a state where the liquid is filled between the exposure auxiliary member 16 and the lithographic printing plate 10. A post-exposure process is performed by so-called surface exposure of the post-exposure light emitted from the light within a predetermined range of the post-exposure position.

  At this time, the photosensitive layer of the developed lithographic printing plate 10 is maintained in a state where it is covered with a liquid and shielded from oxygen in the air. Therefore, in the developed photosensitive layer, the influence of polymerization inhibition by oxygen is exerted. Thus, the entire photosensitive layer forming the image is polymerized and cured so as to allow the radical polymerization reaction to proceed without being subjected to heat, and the printing durability of the lithographic printing plate 10 can be improved.

  Note that the configuration, operation, and effects of the post-exposure apparatus according to the second embodiment other than those described above are the same as those of the first embodiment described above, and thus the description thereof is omitted.

  Next, a third embodiment relating to a post-exposure device for a lithographic printing plate according to the present invention will be described with reference to FIG. In the post-exposure apparatus according to the third embodiment, the liquid is supplied onto the lithographic printing plate 10 by using the transport roller 12 closest to the upstream side in the transport direction with respect to the post-exposure position on the transport path. Further, in the post-exposure apparatus according to the third embodiment, the post-exposure processing is performed directly by the light irradiation means 20 without using an exposure auxiliary member in a state where a liquid layer is formed on the planographic printing plate 10. Configure as follows.

  Therefore, the liquid is made to flow down from the liquid shower bar 26 on the outer peripheral surface on the downstream side in the transport direction with respect to the vertical line passing through the center of the transport roller 12 in the transport roller 12 closest to the upstream side in the transport direction from the post-exposure position. Constitute.

  In this post-exposure apparatus, a flow-down guide member 15 that guides the liquid so as to flow on the average along the outer peripheral surface of the transport roller 12 closest to the upstream side in the transport direction from the post-exposure position is installed.

  The flow-down guide member 15 includes an arcuate guide portion 15A disposed at a predetermined interval with respect to the outer peripheral surface of the conveying roller 12, and a substantially radial direction of the conveying roller 12 from the upper end portion of the arcuate guide portion 15A. And a discharge guide portion 15C extending in parallel to the surface of the planographic printing plate 10 from the lower end portion of the arcuate guide portion 15A.

  Further, in order to receive the liquid flowing down from the liquid shower bar 26 in combination with the introduction guide portion 15B of the flow guide member 15 at a portion of the transport roller 12, a predetermined distance from the introduction guide portion 15B. The auxiliary flow guide member 19 is arranged so as to extend in the tangential direction of the conveying roller 12 in a state of opening and facing.

  In the post-exposure apparatus according to the third embodiment configured as described above, the liquid flowing down from the liquid shower bar 26 is received by the introduction guide portion 15B and the auxiliary flow-down guide member 19, and the outer peripheral surface of the transport roller 12 and the circular arc shape. The guide portion 15A is introduced between the guide portions 15A, and the space between the guide portions 15A flows along the outer peripheral surface of the conveying roller 12 and is guided onto the planographic printing plate 10. Thus, the liquid guided onto the lithographic printing plate 10 is guided by the discharge guide portion 15C and supplied on the entire surface of the photosensitive layer of the lithographic printing plate 10 on the average, and is conveyed upstream of the post-exposure position in the conveyance direction. It spreads between the conveying rollers 12 and 14 disposed on the downstream side in the direction, and accumulates in a layered state with a predetermined thickness due to surface tension.

When configured in this way, between the transport roller 12 disposed immediately upstream of the post-exposure position in the transport direction and the transport roller 12 disposed immediately downstream of the post-exposure position in the transport direction, Since it is not necessary to provide a space for the liquid to flow down from the liquid shower bar 26,
The post-exposure is performed by bringing the transport roller 12 disposed in the immediate vicinity of the upstream side in the transport direction from the post-exposure position and the transport roller 12 disposed in the immediate vicinity of the downstream side in the transport direction closer to the post-exposure position. The apparatus can be miniaturized.

  Further, in this post-exposure apparatus, an LED array light source provided with a plurality of LEDs 20A as the light irradiation means 20 is disposed above the post-exposure position, and the planographic printing plate 10 is passed from the LED 20A through a thin layer for blocking oxygen. The post-exposure photosensitive layer is irradiated with post-exposure light.

  In the post-exposure apparatus, even if some unevenness occurs on the surface of the oxygen-blocking liquid layer formed on the developed photosensitive layer of the lithographic printing plate 10, the post-exposure processing is performed by irradiating light from the LED 20A. There is no hindrance in doing. This is different from the case where the recording laser beam is focused on the photosensitive layer of the lithographic printing plate 10, and radical polymerization is performed by irradiating the developed photosensitive layer of the lithographic printing plate 10 with light of a predetermined wavelength for post-exposure. This is because, as long as the reaction can be generated, the unevenness formed on the surface of the oxygen blocking liquid layer does not affect the generation of the radical polymerization reaction even if the light for post-exposure is scattered.

  In the first embodiment shown in FIGS. 2 and 3 described above, the exposure assisting member 16 is omitted, and the development process of the planographic printing plate 10 is performed from the LED 20A through the oxygen blocking liquid layer. You may comprise so that the light for post-exposure may be irradiated.

  Further, in the post-exposure apparatus, by providing the flow guide member 15 corresponding to the transport roller 12 from which the liquid flows down from the liquid shower bar 26, the liquid that has flowed down rebounds and adheres to the LED 20A as the light irradiation means 20. Can be prevented.

  Note that the configuration, operation, and effects of the post-exposure apparatus according to the third embodiment other than those described above are the same as those of the first embodiment described above, and thus the description thereof is omitted.

In addition, although the example which used LED as a light irradiation means was demonstrated above, for example, a carbon arc lamp, a mercury lamp, a gallium lamp, a metal halide lamp, a xenon lamp, a tungsten lamp, various laser lights etc. can be used. It is. Furthermore, at least 0.05 mJ / cm ² or more amount of the entire surface exposure is preferably in order to obtain sufficient printing durability, more preferably 0.5 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.

Prior to the above development processing, the lithographic printing plate precursor is exposed through a transparent original image having a line image, a halftone dot image or the like, or imagewise exposed by laser beam scanning or the like using digital data.
A desirable wavelength of the light source is 350 nm to 450 nm, and specifically, an InGaN semiconductor laser is suitable. The exposure mechanism may be any of an internal drum system, an external drum system, a flat bed system, and the like.

Other exposure light beams 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. can also be used.
As available laser light sources 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), as a 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 and AlGaInP, AlGaAs semiconductor (300 nm to 350 nm, 5 mW to 100 mW) ), AlGaInN (350 nm to 450 nm, 5 mW to 30 mW), and N ₂ laser (337 nm, pulse 0.1 to 10 mJ) and XeF (351 nm, pulse 10 to 250 mJ) as a pulse laser. In particular, 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.

As the lithographic printing plate exposure apparatus of the scanning exposure system, there are an internal drum system, an external drum system, and a flat bed system as an exposure mechanism, and a light source that can continuously oscillate among the above light sources can be preferably used. . Practically, the following exposure apparatus is particularly preferable in terms of the relationship between the photosensitive material sensitivity and the plate making time.
・ Single beam to triple beam exposure equipment that uses one or more gas lasers or solid-state laser light sources so that the internal drum system produces a semiconductor laser with a total output of 20 mW or more. One or more semiconductor lasers, gas lasers or solid-state lasers are used so that the total output is 20 mW or more with a multi-beam (1 to 10) exposure device / outer drum system using one or more semiconductor lasers, gas lasers or solid-state lasers. Multi-beam (1 to 9) exposure apparatus and multi-beam (10 or more) exposure apparatus using one or more semiconductor lasers or solid-state lasers so that the total output is 20 mW or more in the external drum system. In general, laser sensitive drawing type lithographic printing plates generally use photosensitive material sensitivity X (J / cm ²
), Exposure area S (cm ² ) of photosensitive material, power q (W) of one laser light source, number of lasers n
The equation (eq 1) is established between the total exposure time t (s).

  X · S = n · q · t (eq 1)

i) In the case of the internal drum (single beam) system, the laser rotation speed f (radians / s), the sub-scanning length Lx (cm) of the photosensitive material, the resolution Z (dots / cm), and the total exposure time t (s) In general, equation (eq 2) holds.

  f · Z · t = Lx (eq 2)

ii) External drum (multi-beam) system Drum rotation speed F (radians / s), photosensitive material sub-scanning length Lx (cm), resolution Z (dots / cm), total exposure time t (s), number of beams In general, formula (eq 3) is established during (n).

  F.Z.n.t = Lx (eq 3)

iii) Flat head (multi-beam) system Polygon mirror rotation speed H (radians / s), photosensitive material sub-scanning length Lx (cm), resolution Z (dots / cm), total exposure time t (s), Equation (eq 4) is generally established between the number of beams (n).

  F.Z.n.t = Lx (eq 4)

Resolution (2560 dpi) required for the actual printing plate, plate size (A1 / B1, sub-scan length 42 inch), exposure conditions of about 20 sheets / hour and photosensitive characteristics of the planographic printing plate precursor of the present invention (photosensitive wavelength, By substituting (sensitivity: about 0.1 mJ / cm ² ) into the above formula, it is understood that a combination with a multi-beam exposure method using a laser having a total output of 20 mW or more is particularly preferable in the planographic printing plate precursor of the present invention. it can. Further, by combining operability, cost, etc., a combination with an external drum type semiconductor laser multi-beam (10 or more) exposure apparatus is most preferable.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these. In addition, about each polymer, ratio of a polymerization unit is molar ratio.

[Preparation of Support 1]
An aluminum plate (material JISA1050) having a thickness of 0.3 mm was etched by being immersed in 10% by mass sodium hydroxide at 60 ° C. for 25 seconds, washed with running water, neutralized and washed with 20% by mass nitric acid, and then washed with water. This was subjected to an electrolytic surface roughening treatment in a 1% by mass nitric acid aqueous solution using a sinusoidal alternating waveform current at an anode time electricity of 300 coulomb / dm ² . Subsequently, after dipping in a 1% by mass aqueous sodium hydroxide solution at 40 ° C. for 5 seconds and then in a 30% by mass sulfuric acid aqueous solution and desmutting at 60 ° C. for 40 seconds, the current density in a 20% by mass sulfuric acid aqueous solution was 2A / current density. Anodization was performed for 2 minutes so that the thickness of the anodized film was 2.7 g / m ² under the condition of dm ² .
Then, it processed at 20 degreeC for 10 second with 1 mass% of sodium silicate aqueous solution.
The center line average roughness (Ra) of the support thus obtained was measured using a needle having a diameter of 2 μm and found to be 0.25 μm (Ra indication according to JIS B0601).

Furthermore, after applying the following undercoat liquid (1) with a bar, it was oven-dried at 80 ° C. for 10 seconds to apply a dry coating amount of 10 mg / m ² , and a support having an undercoat layer used in the following experiments. Produced.

<Undercoat liquid (1)>
・ Undercoat compound (1) 0.017 g
・ Methanol 9.00 g
・ Water 1.00g

[Preparation of lithographic printing plate precursor (1)]
A photosensitive layer coating solution (1) having the following composition was bar coated on the support provided with the undercoat layer, followed by oven drying at 70 ° C. for 60 seconds, and a photosensitive layer having a dry coating amount of 1.1 g / m ² . A protective layer coating solution (1) having the following composition is applied on the substrate using a bar so that the dry coating amount is 0.2 g / m ^2, and then dried at 125 ° C. for 70 seconds. Thus, a lithographic printing plate precursor (1) was obtained.

<Photosensitive layer coating solution (1)>
・ The following binder polymer (1) (average molecular weight 80,000) 0.54 g
・ Polymerizable compound 0.48g
(Dipentaerythritol pentaacrylate, Nippon Kayaku Co., Ltd., SR399E)
・ The following sensitizing dye (1) 0.06 g
・ The following polymerization initiator (1) 0.18 g
・ The following chain transfer agent (1) 0.02 g
・ 0.40 g of ε-phthalocyanine pigment dispersion
(Pigment: 15 parts by mass, dispersant Binder 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 0.01g
N-nitrosophenylhydroxylamine aluminum salt ・ The following water-soluble fluorosurfactant (1) 0.001 g
・ Polyoxyethylene-polyoxypropylene condensate 0.04g
(Asahi Denka Kogyo Co., Ltd., Pluronic L44)
・ Tetraethylamine hydrochloride 0.01g
・ 3.5 g of 1-methoxy-2-propanol
・ Methyl ethyl ketone 8.0g

Protective layer coating solution (1)
・ The following mica dispersion (1) 13.0 g
Polyvinyl alcohol (saponification degree 98 mol%, polymerization degree 500) 1.3 g
-Sodium 2-ethylhexyl sulfosuccinate 0.2g
・ Poly (vinyl pyrrolidone / vinyl acetate (1/1)) molecular weight 70,000 g
・ Surfactant (Emalex 710, manufactured by Nippon Emulsion Co., Ltd.) 0.05g
・ 133g of water

(Preparation of mica dispersion (1))
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) is 0.5 μm. A mica dispersion (1) was obtained.

[Preparation of lithographic printing plate precursor (2)]
The lithographic printing plate precursor (1) was prepared in the same manner as the lithographic printing plate precursor (1) except that the binder polymer (1) of the photosensitive layer coating solution (1) was changed to the following binder polymer (5) (acid value 1.9 meq / g). A printing plate precursor (2) was obtained.

[Preparation of lithographic printing plate precursor (3)]
A lithographic printing plate precursor (3) was obtained in the same manner as the production of the lithographic printing plate precursor (1) except that the photosensitive layer coating solution (1) was changed to a photosensitive layer coating solution (2) having the following composition.

<Image recording layer coating solution (2)>
・ 0.2 g of the above polymerization initiator (1)
-0.1 g of the above sensitizing dye (1)
・ Binder polymer (1) (average molecular weight 80,000) 3.0 g
-Polymerizable compound 6.2g
Isocyanuric acid EO-modified diacrylate (Aronix M-215 manufactured by Toa Gosei Co., Ltd.)
・ Royco Crystal Violet 0.2g
・ 0.1 g of the above-mentioned fluorosurfactant (1)
・ The following microcapsule (1) dispersion 25.0 g
・ Methyl ethyl ketone 35.0g
・ 3-methoxy-2-propanol 35.0 g

(Synthesis of microcapsule (1))
As an oil phase component, trimethylolpropane and xylene diisocyanate adduct (manufactured by Mitsui Takeda Chemical Co., Ltd., Takenate D-110N) 10 g, dipentaerythritol pentaacrylate (manufactured by Nippon Kayaku Co., Ltd., SR399E) 4.15 g , And 0.1 g of Pionein A-41C (manufactured by Takemoto Yushi Co., Ltd.) were dissolved in 17 g of ethyl acetate. PVA- as water phase component
40 g of a 4% by weight aqueous solution of 205 was prepared. The oil phase component and the aqueous phase component were mixed and emulsified for 10 minutes at 12000 rpm using a homogenizer. The obtained emulsion was added to 25 g of distilled water, stirred at room temperature for 30 minutes, and then stirred at 40 ° C. for 3 hours. The microcapsule liquid (1) thus obtained was diluted with distilled water so that the solid content concentration became 20% by mass. The average particle size was 0.25 μm.

[Preparation of lithographic printing plate precursor (4)]
The lithographic printing plate precursor (1) is the same as the lithographic printing plate precursor (1) except that the binder polymer (1) of the photosensitive layer coating solution (1) is changed to the following binder polymer (2) (acid value 0 meq / g). 4) was obtained.

[Preparation of lithographic printing plate precursor (5)]
The lithographic printing plate precursor (1) is the same as the lithographic printing plate precursor (1) except that the binder polymer (1) of the photosensitive layer coating solution (1) is changed to the following binder polymer (3) (acid value 0 meq / g). 5) was obtained.

[Preparation of lithographic printing plate precursor (6)]
The binder polymer (1) of the photosensitive layer coating solution (1) is changed to the following binder polymer (4) (n
The lithographic printing plate precursor (6) was obtained in the same manner as the lithographic printing plate precursor (1) except that the average value was changed to 17 and the acid value was 0 meq / g.

[Preparation of lithographic printing plate precursor (7)]
A lithographic printing plate precursor (7) was obtained in the same manner as the lithographic printing plate precursor (1) except that the chain transfer agent (1) in the photosensitive layer coating solution (1) was changed to the following chain transfer agent (2). .

[Preparation of lithographic printing plate precursor (8)]
A lithographic printing plate precursor (8) was obtained in the same manner as the lithographic printing plate precursor (1) except that the chain transfer agent (1) in the photosensitive layer coating solution (1) was changed to the following chain transfer agent (3). .

Chain transfer agent (3)

[Preparation of lithographic printing plate precursor (9)]
The lithographic printing plate precursor except that the protective layer coating solution (1) is changed to a protective layer coating solution (2) having the following composition and applied using a bar so that the dry coating amount is 0.75 g / m ^2. A lithographic printing plate precursor (9) was obtained in the same manner as in the preparation of (1).

Protective layer coating solution (2)
Polyvinyl alcohol (saponification degree 98 mol%, polymerization degree 500) 40 g
Polyvinylpyrrolidone (molecular weight 50,000) 5g
Poly (vinyl pyrrolidone / vinyl acetate (1/1)) molecular weight 70,000 0.5g
Surfactant 0.5g
(Polyoxyethylene lauryl ether, Emarex 710, manufactured by Nippon Emulsion Co., Ltd.)
950g of water

[Preparation of lithographic printing plate precursor (10)]
A lithographic printing plate precursor (10) was obtained in the same manner as the production of the lithographic printing plate precursor (1) except that the support was changed to the following support 2.

(Preparation of support 2)
In order to remove the rolling oil on the surface of a 0.3 mm thick aluminum plate (material JIS A1050), a degreasing treatment was performed at 50 ° C. for 30 seconds using a 10 mass% sodium aluminate aqueous solution, and then the hair diameter was 0.3 mm. The aluminum surface was grained using three bundle-planted nylon brushes and a pumice-water suspension (specific gravity 1.1 g / cm ³ ) having a median diameter of 25 μm and washed thoroughly with water. This plate was etched by being immersed in a 25 mass% sodium hydroxide aqueous solution at 45 ° C for 9 seconds, washed with water, further immersed in 20 mass% nitric acid at 60 ° C for 20 seconds, and washed with water. At this time, the etching amount of the grained surface was about 3 g / m ² .

Next, an electrochemical roughening treatment was performed continuously using an alternating voltage of 60 Hz. The electrolytic solution at this time was a 1% by mass nitric acid aqueous solution (containing 0.5% by mass of aluminum ions) and a liquid temperature of 50 ° C. The AC power supply waveform is electrochemical roughening treatment using a trapezoidal rectangular wave AC with a time TP of 0.8 msec until the current value reaches a peak from zero, a duty ratio of 1: 1, and a trapezoidal rectangular wave AC. Went. Ferrite was used for the auxiliary anode. The current density was 30 A / dm ² at the peak current value, and 5% of the current flowing from the power source was shunted to the auxiliary anode. The amount of electricity in nitric acid electrolysis was 175 C / dm ² when the aluminum plate was the anode. Then, water washing by spraying was performed.

Next, a 0.5% by mass hydrochloric acid aqueous solution (containing 0.5% by mass of aluminum ions) and an electrolytic solution having a liquid temperature of 50 ° C. and nitric acid electrolysis under the condition of an electric quantity of 50 C / dm ² when the aluminum plate is an anode. In the same manner as above, an electrochemical surface roughening treatment was performed, followed by washing with water by spraying. The plate was provided with a direct current anodized film of 2.5 g / m ² at a current density of 15 A / dm ² using 15% by mass sulfuric acid (containing 0.5% by mass of aluminum ions) as an electrolytic solution, then washed with water and dried. Then, it processed at 20 degreeC for 10 second with 1 mass% of sodium silicate aqueous solution.
The center line average roughness (Ra) of the support thus obtained was measured using a needle having a diameter of 2 μm and found to be 0.51 μm (Ra indication according to JIS B0601).

After applying the following undercoat liquid (2) to the thus treated aluminum plate with a bar, it was oven dried at 80 ° C. for 20 seconds to apply a dry coating amount of 10 mg / m ² to prepare a support. did.

Undercoat liquid (2)
・ 100g of the following sol solution
・ Methanol 900g

Sol solution ・ Phosmer PE (Unichemical Co., Ltd.) 5g
・ Methanol 45g
・ Water 10g
・ 85% phosphoric acid 5g
・ Tetraethoxysilane 20g
・ 3-Methacryloxypropyltrimethoxysilane 15g

[Examples 1 to 10]
<Exposure, development and printing>
Each of the lithographic printing plate precursors (1) to (10) was subjected to image exposure using a violet semiconductor laser plate setter Vx9600 manufactured by FUJIFILM Electronic Imaging Ltd (equipped with InGaN semiconductor laser 405 nm ± 10 nm emission / output 30 mW). The image was drawn at a resolution of 2438 dpi using an FM screen (TAFFETA 20) manufactured by Fuji Photo Film Co., Ltd., and a 50% flat screen was drawn with a plate exposure of 0.05 mJ / cm ² .
Thereafter, the developing solution (1) having the following composition was used, and development processing was carried out with an automatic developing processor having a structure shown in FIG. The pH of the developer was 5. The automatic processor is an automatic processor having two rotating brush rolls. As the rotating brush roll, the first brush roll includes a polybutylene terephthalate fiber (hair diameter 200 μm, hair length 17 mm). ) Is used, and the second brush roll is made of polybutylene terephthalate at a speed of 200 revolutions per minute in the same direction as the conveying direction (peripheral speed of the brush tip 0.52 m / sec). Using a brush roll with an outer diameter of 50 mm in which fibers (hair diameter 200 μm, hair length 17 mm) are implanted, rotate 200 times per minute in the direction opposite to the conveying direction (peripheral speed of brush tip 0.52 m / sec) It was. The planographic printing plate precursor was transported at a transport speed of 100 cm / min.
The developer was showered from the spray pipe with a circulation pump and supplied to the plate surface. The tank capacity of the developer was 10 liters.

Developer (1)
・ Water 100g
・ Benzyl alcohol 1g
・ Polyoxyethylene naphthyl ether (oxyethylene average number n = 13) 1g
・ Dioctyl sulfosuccinate sodium salt 0.5g
・ 1g gum arabic
・ Ethylene glycol 0.5g
・ Primary ammonium phosphate 0.05g
・ Citric acid 0.05g
・ Ethylenediaminetetraacetate tetrasodium salt 0.05g

Next, within 30 seconds after development, the developed lithographic printing plate was subjected to whole-surface dew exposure using an exposure apparatus having a structure shown in FIG. As the liquid for blocking oxygen, a liquid having the same composition as that of the developer (1) was used. An LED having a wavelength of 395 nm was used as the exposure light source. The planographic printing plate was transported at a transport speed of 100 cm / min, and the exposure energy amount on the plate surface was 0.3 mJ / cm ² .
Next, it was attached to a printing machine SOR-M manufactured by Heidelberg, and dampening water (EU-3 (Etch solution manufactured by Fuji Photo Film Co., Ltd.) / Water / isopropyl alcohol = 1/89/10 (volume ratio)) and TRANS- Printing was performed at a printing speed of 6000 sheets per hour using G (N) black ink (manufactured by Dainippon Ink & Chemicals, Inc.).

<Print durability>
Printing was performed as described above. As the number of printed sheets is increased, the image on the photosensitive layer formed on the planographic printing plate gradually wears out and the ink receptivity is lowered. Accordingly, the ink density of the image on the printing paper is lowered.
Therefore, the printing durability was evaluated based on the number of printed sheets when the ink density (reflection density) was reduced by 0.1 from the start of printing.
<Developability>
The obtained lithographic printing plate precursor was exposed and developed as described above. After the development processing, the non-image area of the lithographic printing plate was visually confirmed to evaluate the presence or absence of the remaining photosensitive layer.
The results are shown in Table 1.

[Comparative Example 1]
A lithographic printing plate was produced in the same manner as in Example (1) except that post-exposure treatment after development was not performed, and printing durability was evaluated. The results are shown in Table 1.

Example 11
Except that the second brush roll of the automatic developing processor was removed and developed, image exposure and development processing were carried out in the same manner as in Example 1, and a part of the non-image part of the lithographic printing plate was The remaining photosensitive layer remained. Thereafter, the post-development exposure process and printing were carried out in the same manner. However, there was no stain on the non-image area and the printing durability was 120,000 sheets.

Example 12
Except for changing polyoxyethylene naphthyl ether of developer (1) to an anionic surfactant having the following structural formula and adding 0.1 g of antifoaming agent FS Antihome DR110N (manufactured by Dow Corning, silicone emulsion) When image exposure, development processing, post-development exposure processing and printing were performed in the same manner as in Example 1, the same evaluation results as in Example 1 were obtained. The pH of the developer was 5.

Example 13
Image exposure, development processing, post-development exposure processing and printing were performed in the same manner as in Example 1, except that the development solution (1) was changed to the following development solution (2) and development processing and post-exposure exposure processing were performed. As a result, the same evaluation results as in Example 1 were obtained. The pH of the developer was 4.5.

Developer (2)
・ Water 100g
・ Sodium alkyl naphthalene sulfonate 5g
(Perox NB-L manufactured by Kao Corporation)
・ 1g gum arabic
・ Primary ammonium phosphate 0.05g
・ Citric acid 0.05g
・ Ethylenediaminetetraacetate tetrasodium salt 0.05g

[Preparation of lithographic printing plate precursor (11)]
A support (3) was prepared in the same manner as the support (1) except that the following undercoat liquid (3) was applied using a bar coater so that the dry coating amount was 2 mg / m ² .

<Undercoat liquid (3)>
Undercoat compound (2) 0.3 g
60.0g of pure water
Methanol 939.7g

A photosensitive layer coating solution (3) having the following composition was bar-coated on the support provided with the undercoat layer, followed by oven drying at 100 ° C. for 60 seconds, and a photosensitive layer having a dry coating amount of 1.4 g / m ² . The protective layer coating solution (2) was applied using a bar so that the dry coating amount was 2.0 g / m ^2, and then dried at 120 ° C. for 60 seconds to obtain a planographic printing plate precursor (11) was obtained.

<Photosensitive layer coating solution (3)>
・ The following binder polymer (6) (average molecular weight 80,000) 0.51 g
・ The following polymerizable compound (1) 0.46 g
-0.035 g of the above sensitizing dye (1)
・ Polymerization initiator (1) 0.10 g
・ The chain transfer agent (2) 0.09 g
・ 0.40 g of ε-phthalocyanine pigment dispersion
(Pigment: 15 parts by mass, dispersant, binder polymer (6): 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 0.01g
N-nitrosophenylhydroxylamine aluminum salt-The above water-soluble fluorosurfactant (1) 0.002 g
・ 7.5 g of 1-methoxy-2-propanol
・ Methyl ethyl ketone 7.5g

Example 14
The lithographic printing plate precursor (11) was subjected to image exposure using a violet semiconductor laser plate setter Vx9600 (equipped with InGaN semiconductor laser 405 nm ± 10 nm light emission / output 30 mW) manufactured by FUJIFILM Electronic Imaging Ltd. The image was drawn at a resolution of 2438 dpi using an FM screen (TAFFETA 20) manufactured by Fuji Photo Film Co., Ltd., and a 50% flat screen was drawn with a plate exposure of 0.05 mJ / cm ² .
Within 30 seconds after image exposure of the exposed lithographic printing plate precursor, development processing and post-exposure exposure processing were performed using an automatic processor LP1250PLX manufactured by Fuji Photo Film Co., Ltd. The automatic developing machine is configured in the order of heating unit / water washing unit / developing unit / rinsing unit / finishing unit. In this example, the heating unit was turned off, and development processing was performed without heating. In the washing unit, the protective layer was removed by washing. In the subsequent development unit, development was performed using a developer obtained by diluting a developer DV-2 (pH 11.95) manufactured by Fuji Photo Film Co., Ltd. five times with water. In the subsequent rinse unit, the exposure unit (21, 23, 25, 20A, 16) shown in FIG. 3 was installed, and exposure was performed with a water film formed on the planographic printing plate. As the exposure light source, an LED having a wavelength of 395 nm was used, and the exposure energy amount on the plate surface was 0.3 mJ / cm ² . In the subsequent finishing unit, a solution obtained by diluting the gum solution FP-2W manufactured by Fuji Photo Film Co., Ltd. twice with water was used for gumming and hot air drying to obtain a planographic printing plate. The temperature of the developer was 28 ° C., and the planographic printing plate was transported at a transport speed of 110 cm / min. The developability was good.
When the obtained lithographic printing plate was evaluated for printing durability in the same manner as in Example 1, the printing durability was 120,000 sheets.

[Comparative Example 2]
In the rinse unit, a lithographic printing plate was produced in the same manner as in Example 14 except that post-development exposure was not performed, and the obtained lithographic printing plate was evaluated in terms of printing durability in the same manner as in Example 1. The printing durability was 40,000 sheets. The developability was good.

Example 15
The lithographic printing plate precursor 1 was used in the same manner as in Example 1 except that a liquid obtained by diluting FP2W (Finisher liquid manufactured by FUJIFILM Corporation) to 3 times volume with tap water was used as the liquid for blocking oxygen. When exposure processing was performed and plate-making printing evaluation was performed, the printing durability was 120,000 sheets and the developability was good.

It is a figure for demonstrating the structure of an automatic processor. It is a perspective view which shows schematic structure concerning 1st Embodiment of the post-exposure apparatus for lithographic printing plates. It is a block diagram which shows the schematic structure concerning 1st Embodiment of the post-exposure apparatus for lithographic printing plates in a partial cross section. It is a block diagram which shows the schematic structure concerning 2nd Embodiment of the post-exposure apparatus for lithographic printing plates in a partial cross section. It is a perspective view which takes out the post-exposure tool and shows the schematic structure concerning 2nd Embodiment of the post-exposure apparatus for lithographic printing plates. It is a disassembled perspective view which takes out the post-exposure tool and shows the schematic structure concerning 2nd Embodiment of the post-exposure apparatus for lithographic printing plates. It is a block diagram which shows the schematic structure concerning 3rd Embodiment of the post-exposure apparatus for lithographic printing plates in a partial cross section.

Explanation of symbols

1: rotating brush roll 2: receiving roll 3: transport roll 4: transport guide plate 5: spray pipe 6: conduit 7: filter 8: plate feeding table 9: discharge plate 10: planographic printing plate 12: transport roller 14: transport Roller 15: Flowing guide member 15A: Guide portion 15B: Introduction guide portion 15C: Discharge guide portion 16: Exposure auxiliary member 16A: Member body 16B: End surface side member 16C: End surface member 16D: Connection end member 17: Auxiliary flow guide member 17A : Liquid guide groove 20: Light irradiation means 21: Plate edge detection sensor 23: Light source lighting control circuit 25: Power source for light source 26: Liquid shower bar 28: Dish member 30: Liquid circulation line 32: Pipe member 34: Filter 36: Pump 38: Heater 39: Dryer 100: Developer tank 101: Circulation pump 102: Plate

Claims (11)

  A lithographic plate having a photosensitive layer containing (A) a sensitizing dye, (B) a radical polymerization initiator, (C) a radical polymerizable compound and (D) a binder polymer, and a protective layer in this order on a hydrophilic support. After the printing plate precursor is exposed to a laser, development processing is performed to remove the protective layer and the photosensitive layer of the non-exposed portion, and then the liquid layer is exposed on the photosensitive layer exposed portion remaining on the surface of the planographic printing plate. A method for preparing a lithographic printing plate, wherein the entire surface is exposed with light having a wavelength that causes radical polymerization.   On the hydrophilic support, it contains (A) a sensitizing dye, (B) a radical polymerization initiator, (C) a radical polymerizable compound, and (D ′) a hydrophobic binder polymer having an acid value of 0.3 meq / g or less. A lithographic printing plate precursor having a photosensitive layer and a protective layer in this order is subjected to laser exposure, and then the plate surface is rubbed with a rubbing member in the presence of a developer having a pH of 2 to 10 by an automatic processor equipped with a rubbing member. Thus, a development process is performed to remove the protective layer and the photosensitive layer in the non-exposed area, and then the photosensitive layer exposed area remaining on the surface of the lithographic printing plate is covered with a liquid layer to cause radical polymerization. A method for producing a lithographic printing plate, comprising exposing the entire surface with light having a wavelength to be emitted.   The (A) sensitizing dye has an absorption maximum in a wavelength region of 350 to 450 nm, and the laser used for exposure is a laser having an oscillation wavelength in a wavelength region of 350 to 450 nm. A method for producing a lithographic printing plate according to claim 1 or 2.   The method for preparing a lithographic printing plate according to any one of claims 1 to 3, wherein the radical polymerization initiator (B) is a hexaarylbiimidazole compound.   The method for preparing a lithographic printing plate according to any one of claims 1 to 4, wherein the photosensitive layer further comprises (E) a chain transfer agent. The method for producing a lithographic printing plate according to claim 5, wherein the chain transfer agent (E) is a thiol compound represented by the following general formula (I).
Here, R represents an alkyl group which may have a substituent, or an aryl group which may have a substituent, and A represents a 5-membered or 6-membered ring having a carbon atom together with an N═C—N moiety. The atomic group which forms the heterocyclic ring of A, and A may further have a substituent.   The (D) binder polymer is at least one selected from the group consisting of a (meth) acrylic acid copolymer having a crosslinkable group in the side chain and a polyurethane resin having a crosslinkable group in the side chain. The method for producing a lithographic printing plate according to any one of claims 1 to 6.   The method of preparing a lithographic printing plate according to any one of claims 1 to 7, wherein a part or all of the photosensitive layer component is encapsulated in a microcapsule.   The method for preparing a lithographic printing plate according to any one of claims 2 to 8, wherein the rubbing member is at least two rotating brush rolls.   The method for preparing a lithographic printing plate according to any one of claims 2 to 9, wherein the pH of the developer is from 3 to 8.   A lithographic plate having a photosensitive layer containing (A) a sensitizing dye, (B) a radical polymerization initiator, (C) a radical polymerizable compound and (D) a binder polymer, and a protective layer in this order on a hydrophilic support. After the printing plate precursor is exposed to a laser, development processing is performed to remove the protective layer and the photosensitive layer of the non-exposed portion, and then the liquid layer is exposed on the photosensitive layer exposed portion remaining on the surface of the planographic printing plate. A lithographic printing plate produced by covering the surface with light and exposing the entire surface with light having a wavelength causing radical polymerization.