JP5433460B2 - Planographic printing plate precursor for newspaper printing and method for producing the same - Google Patents

Description

  The present invention relates to a lithographic printing plate precursor for newspaper printing. More specifically, the present invention relates to a lithographic printing plate precursor for newspaper printing capable of image exposure by laser and on-press development, a method for producing the same, and a plate making method for on-press developing the lithographic printing plate precursor.

In general, a lithographic printing plate is composed of an oleophilic image area that receives ink and a hydrophilic non-image area that receives dampening water in the printing process. Lithographic printing utilizes the property that water and oil-based inks repel each other, so that the oleophilic image area of the lithographic printing plate is the ink receiving area, and the hydrophilic non-image area is dampened with the water receiving area (ink non-receiving area). In this method, a difference in ink adhesion is caused on the surface of the lithographic printing plate, and after ink is applied only to the image area, the ink is transferred to a printing medium such as paper and printed.
In order to produce this lithographic printing plate, conventionally, a lithographic printing plate precursor (PS plate) in which an oleophilic photosensitive resin layer (image recording layer) is provided on a hydrophilic support is used. After exposure through a mask such as a film, development with an alkaline developer is performed to leave the image recording layer corresponding to the image area, and dissolve and remove the unnecessary image recording layer corresponding to the non-image area. And obtained a lithographic printing plate.

  Due to recent advances in this field, lithographic printing plates are now available with CTP (computer to plate) technology. That is, a lithographic printing plate can be obtained by scanning and exposing a lithographic printing plate precursor directly using a laser or a laser diode without a lith film, and developing it.

  Along with the above progress, problems related to the lithographic printing plate precursor have been changed to improvements in image formation characteristics, printing characteristics, physical characteristics and the like corresponding to the CTP technology. In addition, due to increasing interest in the global environment, environmental issues related to waste liquids associated with wet processing such as development processing have been highlighted as another issue related to lithographic printing plate precursors.

For the above environmental problems, simplification and no processing of development or plate making are directed. As one simple plate making method, a method called “on-press development” is performed. That is, after the exposure of the lithographic printing plate precursor, conventional development is not performed, but it is mounted on a printing machine as it is, and unnecessary portions of the image recording layer are removed at the initial stage of a normal printing process.
In addition, as a simple development method, a method called “gum development” in which unnecessary portions of the image recording layer are removed with a finisher or gum solution having a pH close to neutral instead of a conventional highly alkaline developer is also performed. ing.

  In the simplification of the plate making operation as described above, a system using a lithographic printing plate precursor and a light source that can be handled in a bright room or under a yellow light is preferable in terms of ease of work. A solid-state laser such as a semiconductor laser or a YAG laser emitting an infrared ray of 1200 nm is used. Further, a UV laser can be used.

  As a lithographic printing plate precursor capable of on-machine development, for example, in Patent Documents 1 and 2, a lithographic printing plate having an image recording layer (thermosensitive layer) containing a microcapsule containing a polymerizable compound on a hydrophilic support. The original edition is listed. Patent Document 3 describes a lithographic printing plate precursor in which an image recording layer (photosensitive layer) containing an infrared absorber, a radical polymerization initiator, and a polymerizable compound is provided on a support. Further, in Patent Document 4, on-press development is possible in which an image recording layer containing a polymerizable compound and a graft polymer having a polyethylene oxide chain in the side chain or a block polymer having a polyethylene oxide block is provided on a support. A planographic printing plate precursor is described.

  When printing on a planographic printing plate, when printing on paper smaller than the size of the printing plate as in a normal sheet-fed printing press, the edge of the printing plate is printed because it is located outside the paper. There is no impact on quality. However, when printing on roll paper continuously using a rotary press such as newspaper printing, the edge of the printing plate is within the roll paper surface, so the ink adhering to the edge is transferred to the paper and printed on the line. And the product value of the printed matter is significantly impaired.

  As a method for preventing the stain on the end in newspaper printing, a method is known in which the end surface of the aluminum support is cut so as to be 10 to 45 degrees with respect to the aluminum surface (see Patent Document 5). In addition, a method has been proposed in which the end of the planographic printing plate is bent downward so that ink is not accumulated at the end (see Patent Document 6). Both of these reduce the adhesion of ink to the edge by processing so that the edge is below the lithographic printing plate surface, and reduce the contact between the edge and the blanket and adhere to the edge. It is intended to prevent the transferred ink from transferring and causing edge stains.

  Furthermore, in addition to making the end part into the specific shape described above, the end part is treated with a desensitizing liquid containing a hydrophilic organic polymer compound such as gum arabic, soybean polysaccharide, phosphoric acid, etc. It has been proposed to make it difficult to stick (see Patent Documents 7 and 8).

JP 2001-277740 A JP 2001-277742 A JP 2002-287334 A US Patent Application Publication No. 2003/0064318 Japanese Patent Publication No.57-46754 JP-A-10-35130 Japanese Patent Laid-Open No. 11-52579 JP 2001-75268 A

The above prior art for preventing edge smearing in newspaper printing has been developed by a system in which a lithographic printing plate precursor is exposed and developed with an automatic developing machine or the like and applied to the printing machine. However, it was found that there was a new problem when on-press development was attempted in newspaper printing. In order to prevent edge contamination, when the end portion was processed to be lower than the lithographic printing plate surface as in the prior art, the end portion was not developed on the machine, and the edge contamination was worsened. This is because the edge is below the surface of the lithographic printing plate, and during on-press development, mechanical contact with the rollers and blanket is insufficient, and the image recording layer cannot be removed, resulting in a residual film. Because. As described above, a new device is required to perform on-press development in newspaper printing and to prevent edge smearing.
The problem of the present invention is to solve this new problem. That is, it is to provide an on-press development type lithographic printing plate precursor for newspaper printing which does not cause edge smearing, a production method thereof, and a plate making method using the lithographic printing plate precursor.

1. Infrared absorbing dye, radical polymerization initiator, radical polymerizable compound and polymer compound having polyoxyalkylene chain in the side chain are contained on the support and developed with printing ink and / or dampening water on the cylinder of the printing press. A lithographic printing plate precursor having a possible image recording layer, for newspaper printing obtained by treating a region within 1 cm from the edge of the lithographic printing plate precursor with a liquid containing an organic solvent and a water-soluble resin A lithographic printing plate precursor.
2. 2. The lithographic printing plate precursor for newspaper printing as described in 1 above, wherein the polyoxyalkylene chain of the polymer compound is a polyoxyethylene chain, and the number of repeating units of oxyethylene is 2 to 50.
3. 3. The lithographic printing plate precursor for newspaper printing as described in 1 or 2 above, wherein the polymer compound is polymer compound fine particles.
4). 3. The lithographic printing plate precursor for newspaper printing as described in 1 or 2 above, wherein the polymer compound is a binder.
5. Between the support and the image recording layer, it has an undercoat layer containing an acidic group adsorbed on the support surface and a polymer compound having a radically polymerizable ethylenically unsaturated bond in the side chain. 5. A lithographic printing plate precursor for newspaper printing according to any one of 4 above.
6). 6. The lithographic printing plate precursor for newspaper printing according to any one of 1 to 5 above, wherein the amount of sag at the end of the lithographic printing plate precursor is 25 μm or less.
7). The lithographic printing plate precursor for newspaper printing according to any one of 1 to 6, wherein the water-soluble resin is a polysaccharide.
8). The lithographic printing plate precursor for newspaper printing according to any one of 1 to 7, wherein the organic solvent is alcohol.
9. 9. The lithographic printing plate precursor for newspaper printing as described in 7 or 8 above, wherein the liquid containing the organic solvent and the water-soluble resin further contains a phosphoric acid compound.
10. Infrared absorbing dye, radical polymerization initiator, radical polymerizable compound and polymer compound having polyoxyalkylene chain in the side chain are contained on the support and developed with printing ink and / or dampening water on the cylinder of the printing press. A process for producing a lithographic printing plate precursor for newspaper printing, characterized in that a region within 1 cm from the edge of the lithographic printing plate precursor having a possible image recording layer is treated with a liquid containing an organic solvent and a water-soluble resin.
11. Infrared absorbing dye, radical polymerization initiator, radical polymerizable compound and polymer compound having polyoxyalkylene chain in the side chain are contained on the support and developed with printing ink and / or dampening water on the cylinder of the printing press. A lithographic printing plate precursor having a possible image recording layer is image-exposed with an infrared laser, and then treated within 1 cm from the edge of the lithographic printing plate precursor with a liquid containing an organic solvent and a water-soluble resin, and then a printing machine A method for making a lithographic printing plate, which is attached to a cylinder and developed with printing ink and / or fountain solution.

In the present invention, the edge portion of the lithographic printing plate precursor is treated with a processing solution containing an organic solvent and a water-soluble resin, thereby preventing the occurrence of residual film on the edge portion during on-press development and preventing edge smearing during printing. We have a lithographic printing plate precursor for newspaper printing.
In Patent Documents 7 and 8, in order to prevent edge smearing, the edge of the lithographic printing plate precursor is coated with a desensitizing liquid containing a hydrophilic organic polymer compound such as gum arabic, soybean polysaccharide, phosphoric acid, etc. Processing is described. However, these prior arts relate to a lithographic printing plate precursor of a type in which development processing is performed with an automatic processor after exposure, and by applying a desensitizing liquid to the end and side of the lithographic printing plate precursor, The defect portion of the anodized film layer is made hydrophilic and the burrs are smoothed to prevent the stains on the edges, and the on-machine development residual film at the edges of the on-machine development type lithographic printing plate precursor as in the present invention is formed. It does not disclose or suggest any issues to be prevented.

  The lithographic printing plate precursor for newspaper printing according to the present invention was able to suppress the occurrence of edge stains by treating an area within 1 cm from the edge with a liquid containing an organic solvent and a water-soluble resin.

It is an example of the cross-sectional shape of the lithographic printing plate precursor edge part cut | judged with the cutting apparatus. It is another example of the cross-sectional shape of the lithographic printing plate precursor edge part cut | judged with the cutting apparatus. It is sectional drawing which shows the cutting part of a slitter apparatus. It is a figure which shows a bundle cutting machine.

The lithographic printing plate precursor for newspaper printing of the present invention comprises an infrared absorbing dye, a radical polymerization initiator, a radical polymerizable compound and a polymer compound having a polyoxyalkylene chain in the side chain on a support, and a cylinder of a printing press. A region within 1 cm from the edge of the lithographic printing plate precursor having an image recording layer developable with printing ink and / or fountain solution is treated with a liquid (processing liquid) containing an organic solvent and a water-soluble resin. Is obtained.
Hereinafter, the treatment liquid of the present invention and then the lithographic printing plate precursor will be described.

[Treatment solution]
The essential components of the treatment liquid of the present invention are (1) an organic solvent and (2) a water-soluble resin. Preferred optional components include a plasticizer, a surfactant for promoting liquid penetration, and a phosphoric acid compound for inhibiting leftover dirt. Other optional components include inorganic salts, preservatives, and antifoaming agents.
These treatment liquids may be aqueous solutions or liquids obtained by emulsifying oil phase components and water phase components.

<Organic solvent>
Examples of the organic solvent used in the present invention include alcohol solvents, ketone solvents, ester solvents, amide solvents, and hydrocarbon solvents. Of these, alcohol solvents and hydrocarbon solvents are preferred.

The alcohol solvent may be a monohydric alcohol or a polyhydric alcohol. As monohydric alcohol, methyl alcohol, n-propyl alcohol, iso-propyl alcohol, n-butyl alcohol, tert-butyl alcohol, n-amyl alcohol, diacetone alcohol, 1-methoxy-2-propanol, furfuryl alcohol 2-octanol, 2-ethylhexanol, nonanol, n-decanol, undecanol, n-dodecanol, trimethylnonyl alcohol, benzyl alcohol, phenethyl alcohol, ethylene glycol monoisoamyl ether, ethylene glycol monophenyl ether, ethylene glycol monobenzyl ether, Examples thereof include ethylene glycol monohexyl ether.
Examples of the polyhydric alcohol include ethylene glycol, propylene glycol, triethylene glycol, butylene glycol, hexylene glycol, diethylene glycol, dipropylene glycol, and glycerin.
Of these, benzyl alcohol, phenethyl alcohol, furfuryl alcohol, and glycerin are particularly preferable.

  Examples of the hydrocarbon solvent include aromatics, aliphatic compounds (mineral spirits), squalane and the like of petroleum fractions.

  Only one organic solvent may be used, or two or more organic solvents may be used in combination. The amount of the organic solvent used is preferably 0.5 to 10% by mass, more preferably 1 to 5% by mass, based on the total mass of the treatment liquid. Within this range, the treatment liquid application portion does not become sticky, and excellent permeability to the image recording layer is excellent.

<Plasticizer>
The treatment agent of the present invention can contain a plasticizer. Examples of the plasticizer include dibutyl phthalate, diheptyl phthalate, di-n-octyl phthalate, di (2-ethylhexyl) phthalate, dinonyl phthalate, didecyl phthalate, dilauryl phthalate, and butyl benzyl phthalate. Aliphatic dibasic esters such as dioctyl adipate, butyl glycol adipate, dioctyl azelate, dibutyl sebacate, di (2-ethylhexyl) sebacate, dioctyl sebacate, epoxidized triglycerides such as epoxidized soybean oil, for example The freezing point of phosphate esters such as tricresyl phosphate, trioctyl phosphate, tristrolol phosphate, benzoates such as benzyl benzoate is 15 ° C. They include plasticizers below.

  Only 1 type of plasticizer may be used and it can also use 2 or more types together. The amount of the plasticizer used is preferably 0.5 to 10% by mass, more preferably 1 to 5% by mass, based on the total mass of the treatment liquid.

<Water-soluble resin>
Examples of water-soluble resins used in the present invention include water-soluble resins classified as polysaccharides, polyvinyl alcohol, polyvinyl pyrrolidone, polyacrylamide and copolymers thereof, vinyl methyl ether / maleic anhydride copolymers, vinyl acetate / anhydrous. Mention may be made of maleic acid copolymers, styrene / maleic anhydride copolymers and the like.
Examples of polysaccharides include starch derivatives (eg, dextrin, enzymatically degraded dextrin, hydroxypropylated starch, carboxymethylated starch, phosphate esterified starch, polyoxyalkylene grafted starch, cyclodextrin), celluloses (eg, carboxymethylcellulose, carboxy Ethyl cellulose, methyl cellulose, hydroxypropyl cellulose, methylpropyl cellulose and the like), carrageenan, alginic acid, guar gum, locust bean gum, xanthan gum, gum arabic, soybean polysaccharide and the like.
Among them, dextrin, starch derivatives such as polyoxyalkylene grafted starch, gum arabic, carboxymethyl cellulose, soybean polysaccharide and the like are preferably used.

  These water-soluble resins can be used in combination of two or more, and can be contained in a range of preferably 5 to 40% by mass, more preferably 10 to 30% by mass based on the total mass of the treatment liquid. Within this range, good on-press developability can be obtained without being difficult to apply due to the high viscosity of the processing solution.

<Phosphate compound>
Examples of the phosphoric acid compound that can be used in the present invention include phosphoric acid, metaphosphoric acid, primary ammonium phosphate, secondary ammonium phosphate, primary sodium phosphate, secondary sodium phosphate, primary potassium phosphate, secondary phosphorus. Examples include potassium acid, sodium tripolyphosphate, potassium pyrophosphate, and sodium hexametaphosphate. Among these, combinations of acids and salts such as phosphoric acid / ammonium phosphate and metaphosphoric acid / ammonium phosphate can be preferably used.
The content of phosphoric acid and / or phosphate in the treatment liquid used in the present invention is preferably 0.5 to 3.0% by mass, more preferably 0.5 to 2 based on the total mass of the treatment liquid. 0.5% by mass. Within this range, it is excellent in leaving dirt and suppressing crystal precipitation after coating.

<Surfactant>
Examples of the surfactant that can be used in the present invention include an anionic surfactant and / or a nonionic surfactant. Anionic surfactants include fatty acid salts, abietic acid salts, hydroxyalkane sulfonates, alkane sulfonates, dialkyl sulfosuccinates, linear alkyl benzene sulfonates, branched alkyl benzene sulfonates, alkyl naphthalene sulfonates. , Alkylphenoxy polyoxyethylene propyl sulfonates, polyoxyethylene alkyl sulfophenyl ether salts, N-methyl-N-oleyl taurine sodium, N-alkyl sulfosuccinic acid monoamide disodium salts, petroleum sulfonates, sulfated castor oil , Sulfated beef tallow oil, fatty acid alkyl ester sulfates, alkyl sulfates, polyoxyethylene alkyl ether sulfates, fatty acid monoglyceride sulfates Tell salt, polyoxyethylene alkylphenyl ether sulfate ester salt, polyoxyethylene styryl phenyl ether sulfate ester salt, alkyl phosphate ester salt, polyoxyethylene alkyl ether phosphate ester salt, polyoxyethylene alkylphenyl ether phosphate ester salt, styrene-anhydrous Examples thereof include partially saponified products of maleic acid copolymers, partially saponified products of olefin-maleic anhydride copolymers, and naphthalene sulfonate formalin condensates. Among these, dialkyl sulfosuccinates, alkyl sulfate esters, and alkyl naphthalene sulfonates are particularly preferably used.

Nonionic surfactants include polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene polystyryl phenyl ether, glycerin fatty acid partial esters, sorbitan fatty acid partial esters, pentaerythritol fatty acid moieties. Esters, propylene glycol monofatty 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, polyoxyethylene glycerin Fatty acid partial esters, fatty acid diethanolamides, N, N-bis-2-hydroxyalkylamines, polyoxyethylene alkyl Amines, triethanolamine fatty acid esters, such as trialkylamine oxides. Of these, polyoxyethylene alkylphenyl ethers, polyoxyethylene-polyoxypropylene block copolymers and the like are preferably used.
Acetylene glycol-based and acetylene alcohol-based oxyethylene adducts, fluorine-based and silicon-based anions, and nonionic surfactants can also be used in the same manner.

  Two or more of these surfactants can be used in combination. For example, a combination of two or more different anionic surfactants or a combination of an anionic surfactant and a nonionic surfactant is preferable.

  The amount of the surfactant used is not particularly limited, but is preferably 0.01 to 20% by mass based on the total mass of the treatment liquid, and the treatment liquid permeability is promoted.

<Other optional components>
The liquid for treating the edge of the lithographic printing plate precursor used in the present invention can contain inorganic salts such as nitrates and sulfates, preservatives, antifoaming agents and the like in addition to the above components. Examples of the inorganic salt include magnesium nitrate, sodium nitrate, potassium nitrate, ammonium nitrate, sodium sulfate, potassium sulfate, ammonium sulfate, sodium hydrogen sulfate, nickel sulfate 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, Examples include 1,1-dibromo-1-nitro-2-propanol.
As the antifoaming agent, a general silicon-based self-emulsifying type, emulsifying type, surfactant nonionic HLB5 or less compound can be used.

<Emulsification type production method>
When preparing as an emulsification type, it can be prepared according to a conventional method. For example, in the emulsification dispersion when producing the treatment liquid used in the present invention, the aqueous phase is prepared at a temperature of 40 ° C. ± 5 ° C., stirred at a high speed, and the prepared oil phase is slowly dropped into the aqueous phase and sufficiently stirred. Thereafter, an emulsion is prepared through a pressure type homogenizer. The treatment liquid is first prepared in a concentrated form, and may be appropriately diluted at the time of use.

[On-press development type lithographic printing plate precursor]
The lithographic printing plate precursor used in the present invention has a support, an image recording layer, an undercoat layer that exists between the support and the image recording layer, and a protective layer that exists on the image recording layer, if necessary.

(Image recording layer)
The image recording layer of the present invention contains an infrared absorbing dye, a radical polymerization initiator, a radical polymerizable compound, and a polymer compound having a polyoxyalkylene chain as a side chain, and is used for printing ink and / or on a cylinder of a printing machine. It is an image recording layer that can be developed with a fountain solution.
Hereinafter, the components of the image recording layer will be described.

<Polymer compound having a polyoxyalkylene chain in the side chain>
By containing a polymer compound having a polyoxyalkylene chain in the side chain (hereinafter also referred to as a specific polymer compound), the permeability of the processing liquid is promoted and the on-press developability is improved.

  Specific polymer compounds include acrylic resin, polyvinyl acetal resin, polyurethane resin, polyurea resin, polyimide resin, polyamide resin, epoxy resin, methacrylic resin, polystyrene resin, novolac phenolic resin, polyester resin, synthetic rubber, natural rubber Among them, an acrylic resin is particularly preferable.

The specific polymer compound is substantially free of a perfluoroalkyl group. “Substantially free of perfluoroalkyl group” means that the mass ratio of fluorine atoms present as a perfluoroalkyl group in the polymer compound is less than 0.5% by mass, and preferably does not contain. The mass ratio of fluorine atoms is measured by elemental analysis.
The “perfluoroalkyl group” is one in which all hydrogen atoms of the alkyl group are substituted with fluorine atoms.

As said alkylene oxide, a C2-C6 alkylene oxide is preferable and especially an ethylene oxide or a propylene oxide is preferable.
2-50 are preferable and, as for the repeating number of the alkylene oxide in a poly (alkylene oxide) site | part, the range of 4-25 is more preferable.
If the number of alkylene oxide repeats is 2 or more, the permeability of the treatment liquid is sufficiently improved, and if the number of repeats is 50 or less, the printing durability due to wear does not deteriorate, which is preferable.

  The poly (alkylene oxide) moiety is preferably contained as a side chain of the polymer compound in a structure represented by the following general formula (1). More preferably, it is contained as a side chain of the acrylic resin in a structure represented by the following general formula (1).

In general formula (1), y is preferably 2 to 50, and more preferably 4 to 25. R ₁ represents a hydrogen atom or an alkyl group, and R ₂ represents a hydrogen atom or an organic group. As an organic group, a C1-C6 alkyl group is preferable, and a methyl group, an ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, isobutyl group, t-butyl group, n- Examples include a pentyl group, an isopentyl group, a neopentyl group, an n-hexyl group, an isohexyl group, a 1,1-dimethylbutyl group, a 2,2-dimethylbutyl group, a cyclopentyl group, and a cyclohexyl group.
Among the above, R ₁ is preferably a hydrogen atom or a methyl group, and most preferably a hydrogen atom.
R ₂ is most preferably a hydrogen atom or a methyl group.

The specific polymer compound may have crosslinkability in order to improve the film strength of the image area. In order to impart crosslinkability to the polymer compound, 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.
Examples of the polymer compound having an ethylenically unsaturated bond in the main chain of the molecule include poly-1,4-butadiene and poly-1,4-isoprene.
Examples of the polymer compound having an ethylenically unsaturated bond in the side chain of the molecule include an ester or amide polymer compound of acrylic acid or methacrylic acid, and an ester or amide residue (-COOR or CONHR Mention may be made of polymer compounds in which R) has an ethylenically unsaturated bond.

Examples of the residue (the R) having an ethylenically unsaturated _{bond, - (CH 2) n CR} 1 = CR 2 R 3, - (CH 2 O) n CH 2 CR 1 = CR 2 R 3, - _{(CH 2 CH 2 O) n} CH 2 CR 1 = CR 2 R 3, - (CH 2) n NH-CO-O-CH 2 CR 1 = CR 2 R 3, - (CH 2) n -O-CO —CR ¹ ═CR ² R ³ and (CH ₂ CH ₂ O) ₂ —X (wherein R ^{1 to} R ³ are each a hydrogen atom, a halogen atom, or an alkyl group having 1 to 20 carbon atoms, an aryl group, and alkoxy. R ¹ and R ² or R ³ may be bonded to each other to form a ring, n represents an integer of 1 to 10. X represents a dicyclopentadienyl residue. Represents a group).

Specific examples of the ester _{residue, -CH 2 CH = CH 2,} ( described in JP Kokoku _{7-21633.) - CH 2 CH 2} O-CH 2 CH = CH 2, -CH 2 C _{(CH 3) = CH 2,} -CH 2 CH = CH-C 6 H 5, -CH 2 CH 2 OCOCH = CH-C 6 H 5, -CH 2 CH 2 -NHCOO-CH 2 CH = CH 2 and CH ₂ CH ₂ O—X (wherein X represents a dicyclopentadienyl residue).
Specific examples of the amide residue include —CH ₂ CH═CH ₂ , —CH ₂ CH ₂ —Y (wherein Y represents a cyclohexene residue), —CH ₂ CH ₂ —OCO—CH═CH _2. Is mentioned.

  Specific polymer compounds having crosslinkability include, for example, free radicals (polymerization initiation radicals or growth radicals in the polymerization process of a polymerizable compound) added to the crosslinkable functional group, and directly or between the polymer compounds Addition polymerization is carried out through the polymerization chain to form a cross-link between the polymer compound molecules and cure. Alternatively, atoms in the polymer compound (for example, hydrogen atoms on carbon atoms adjacent to the functional bridging group) are extracted by free radicals to form polymer compound radicals, which are bonded to each other, thereby Crosslinks are formed between the compound molecules and harden.

  The content of the crosslinkable group in the specific polymer compound (content of unsaturated double bond capable of radical polymerization by iodometric titration) is preferably 0.1 to 10.0 mmol, more preferably 1 g per 1 g of the polymer compound. It is 1.0-7.0 mmol, Most preferably, it is 2.0-5.5 mmol. Within this range, good sensitivity and good storage stability can be obtained.

  The specific polymer compound of the present invention may further contain a copolymer component for the purpose of improving various performances such as image strength as long as the effects of the present invention are not impaired. As a preferable structure of the copolymer component, one represented by the following general formula (2) can be exemplified.

In the general formula (2), R ²¹ represents a hydrogen atom or a methyl group. R ²² represents a substituent.
Preferable examples of R ²² include an ester group, an amide group, a cyano group, a hydroxy group, or an aryl group. Especially, the phenyl group which may have an ester group, an amide group, or a substituent is preferable. Examples of the substituent for the phenyl group include an alkyl group, an aralkyl group, an alkoxy group, and an acetoxymethyl group.

  Examples of the copolymer component represented by the general formula (2) include acrylic acid esters, methacrylic acid esters, acrylamides, methacrylamides, N-substituted acrylamides, N-substituted methacrylamides, N, N -2 substituted acrylamides, N, N-2 substituted methacrylamides, styrenes, acrylonitriles, methacrylonitriles and the like. Preferably, acrylic esters, methacrylic esters, acrylamides, methacrylamides, N-substituted acrylamides, N-substituted methacrylamides, N, N-2 substituted acrylamides, N, N-2 substituted methacrylamides And styrenes.

  Specifically, for example, acrylic esters such as alkyl acrylate (the alkyl group preferably has 1 to 20 carbon atoms), (for example, methyl acrylate, ethyl acrylate, propyl acrylate, acrylic acid) Butyl, amyl acrylate, ethyl hexyl acrylate, octyl acrylate, 2,2-dimethylhydroxypropyl acrylate, 5-hydroxypentyl acrylate, trimethylolpropane monoacrylate, pentaerythritol monoacrylate, glycidyl acrylate, benzyl acrylate, etc.), aryl acrylate (For example, phenyl acrylate), methacrylic acid esters (for example, methyl methacrylate) such as alkyl methacrylate (the alkyl group preferably has 1 to 20 carbon atoms). , Ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, amyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, octyl methacrylate, 4-hydroxybutyl methacrylate, 5-hydroxypentyl methacrylate, 2,2-dimethyl-3-hydroxypropyl methacrylate Styrenes such as methyl styrene, dimethyl styrene, trimethyl styrene, ethyl styrene, diethyl styrene, isopropyl styrene, butyl styrene, hexyl, trimethylolpropane monomethacrylate, pentaerythritol monomethacrylate, glycidyl methacrylate, etc. Styrene, chloromethylstyrene, Butoxy methyl styrene, etc. acetoxymethyl styrene), acrylonitrile, methacrylonitrile, a radical polymerizable compound containing a carboxylic acid (acrylic acid, methacrylic acid, and salts of these acids group). Acrylonitrile is preferred from the viewpoint of printing durability.

  The ratio of the repeating unit having the poly (alkylene oxide) moiety to the total repeating units constituting the specific polymer compound is not particularly limited, but is preferably 0.5 to 80 mol%, more preferably 0.5 to 50 mol%.

  Specific examples A-1 to A-19 of the specific polymer compound used in the present invention are shown below, but the present invention is not limited thereto. The ratio of repeating units is a molar ratio.

  The specific polymer compound in the present invention preferably has a mass average molar mass (Mw) of 2000 or more, more preferably 5000 or more, and still more preferably 10,000 to 300,000.

  In the present invention, if necessary, hydrophilic polymer compounds such as polyacrylic acid and polyvinyl alcohol described in JP-A-2008-195018 can be used in combination. Further, a lipophilic polymer compound and a hydrophilic polymer compound can be used in combination.

  The form of the specific polymer compound of the present invention may be present in the image recording layer as a binder that functions to connect each material, or may be present in the form of fine particles. When present in the form of fine particles, the average particle size is in the range of 10 to 1000 nm, preferably in the range of 20 to 300 nm, and particularly preferably in the range of 30 to 120 nm.

  The content of the specific polymer compound of the present invention is preferably 10 to 80% by mass, more preferably 15 to 70% by mass, based on the total solid content of the image recording layer. In the range of 10 to 80% by mass, it is preferable because both the treatment liquid permeability and the image forming property can be reliably achieved.

<Infrared absorbing dye>
The infrared absorbing dye has a function of converting the absorbed infrared light into heat and a function of being excited by the infrared light and transferring electrons and / or energy to a radical polymerization initiator described later. The infrared absorbing dye used in the present invention is a dye having an absorption maximum at a wavelength of 760 to 1200 nm.

As the dye, commercially available dyes and known dyes described in documents such as “Dye Handbook” (edited by the Society for Synthetic Organic Chemistry, published in 1970) can be used. Specifically, dyes such as azo dyes, metal complex azo dyes, pyrazolone azo dyes, naphthoquinone dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinoneimine dyes, methine dyes, cyanine dyes, squarylium dyes, pyrylium salts, metal thiolate complexes, etc. Is mentioned.
Particularly preferred among these dyes are cyanine dyes, squarylium dyes, pyrylium salts, nickel thiolate complexes, and indolenine cyanine dyes. Further, cyanine dyes and indolenine cyanine dyes are preferred, and particularly preferred examples include cyanine dyes represented by the following general formula (a).

In the general formula (a), X ¹ represents a hydrogen atom, a halogen ^{atom, -N (R 9) (R} 10), - X ² -L ¹ or a group shown below. Here, R ⁹ and R ¹⁰ may be the same or different and each may have a substituent, an aryl group having 6 to 10 carbon atoms, an alkyl group having 1 to 8 carbon atoms, a hydrogen atom R ⁹ and R ¹⁰ may be bonded to each other to form a ring. Of these, a phenyl group is preferred (—NPh ₂ ). X ² represents an oxygen atom or a sulfur atom, and L ¹ represents a hydrocarbon group having 1 to 12 carbon atoms, a heteroaryl group, or a hydrocarbon group having 1 to 12 carbon atoms including a hetero atom. In addition, a hetero atom here shows N, S, O, a halogen atom, and Se. In the group shown below, Xa ^- has Za described later ^- is defined as for, Ra represents a hydrogen atom, an alkyl group, an aryl group, a substituted or unsubstituted amino group, substituted or unsubstituted amino group and a halogen atom.

R ¹ and R ² each independently represents a hydrocarbon group having 1 to 12 carbon atoms. From the storage stability of the image recording layer coating solution, R ¹ and R ² are preferably hydrocarbon groups having 2 or more carbon atoms. R ¹ and R ² may be connected to each other to form a ring, and when forming a ring, it is particularly preferable to form a 5-membered ring or a 6-membered ring.

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

Specific examples of the cyanine dye represented by formula (a) that can be suitably used include compounds described in paragraphs [0017] to [0019] of JP-A No. 2001-133969, and JP-A No. 2002-023360. Paragraph numbers [0016] to [0021] of JP-A No. 2002-040638, compounds described in paragraph Nos. [0012] to [0037] of JP-A No. 2002-040638, preferably paragraph Nos. [0034] of JP-A No. 2002-278057 [0041], compounds described in paragraph numbers [0080] to [0086] of JP 2008-195018 A, most preferably compounds described in paragraph numbers [0035] to [0043] of JP 2007-90850 A Is mentioned.
In addition, compounds described in paragraph numbers [0008] to [0009] of JP-A No. 5-5005 and paragraph numbers [0022] to [0025] of JP-A No. 2001-222101 can also be preferably used.

  Moreover, only 1 type may be used for these infrared absorption dyes, 2 or more types may be used together, and infrared absorption pigments other than an infrared absorption dye may be used together. As the pigment, compounds described in JP 2008-195018 A [0072] to [0076] are preferable.

  The content of the infrared absorbing dye in the image recording layer in the present invention is preferably 0.1 to 10.0% by mass, more preferably 0.5 to 5.0% by mass of the total solid content of the image recording layer.

<Radical polymerization initiator>
The radical polymerization initiator used in the present invention is a compound that initiates and accelerates polymerization of a radical polymerizable compound. As the radical polymerization initiator that can be used in the present invention, a known thermal polymerization initiator, a compound having a bond with a small bond dissociation energy, a photopolymerization initiator, and the like can be used.

  Examples of the radical polymerization initiator in the present invention include (a) an organic halide, (b) a carbonyl compound, (c) an azo compound, (d) an organic peroxide, (e) a metallocene compound, and (f) an azide compound. (G) hexaarylbiimidazole compound, (h) organic borate compound, (i) disulfone compound, (j) oxime ester compound, (k) onium salt compound.

  (A) As the organic halide, compounds described in paragraph numbers [0022] to [0023] of JP-A-2008-195018 are preferable.

  (B) As the carbonyl compound, compounds described in paragraph [0024] of JP-A-2008-195018 are preferable.

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

  (D) As the organic peroxide, for example, compounds described in paragraph [0025] of JP-A-2008-195018 are preferable.

  As the (e) metallocene compound, for example, the compound described in paragraph [0026] of JP-A-2008-195018 is preferable.

(F) Examples of the azide compound include 2,6-bis (4-azidobenzylidene) -4-methylcyclohexanone.
(G) As the hexaarylbiimidazole compound, for example, a compound described in paragraph [0027] of JP-A-2008-195018 is preferable.

  (H) As the organic borate compound, for example, a compound described in paragraph [0028] of JP-A-2008-195018 is preferable.

  (I) Examples of the disulfone compound include compounds described in JP-A No. 61-166544.

  (J) As the oxime ester compound, for example, compounds described in paragraph numbers [0028] to [0030] of JP-A-2008-195018 are preferable.

  (K) Examples of the onium salt compounds include S.I. I. Schlesinger, Photogr. Sci. Eng. , 18, 387 (1974), T.A. S. Bal et al, Polymer, 21, 423 (1980), diazonium salts described in JP-A-5-158230, ammonium described in US Pat. No. 4,069,055, JP-A-4-365049, and the like. Salt, phosphonium salts described in U.S. Pat. Nos. 4,069,055 and 4,069,056, EP 104,143, U.S. Patent Application Publication No. 2008/0311520 JP-A-2-150848, JP-A-2008-195018, or J.P. V. Crivello et al, Macromolecules, 10 (6), 1307 (1977), iodonium salts, European Patent Nos. 370,693, 233,567, 297,443, 297,442, US Patent 4,933,377, 4,760,013, 4,734,444, 2,833,827, German Patents 2,904,626, 3,604,580, Sulfonium salts described in each specification of JP-A-3,604,581; V. Crivello et al, J.A. Polymer Sci. , Polymer Chem. Ed. , 17, 1047 (1979), a selenonium salt described in C.I. S. Wen et al, Teh, Proc. Conf. Rad. Curing ASIA, p478 Tokyo, Oct (1988), and onium salts such as azinium salts described in JP-A-2008-195018.

  Of these, more preferred are onium salts, especially iodonium salts, sulfonium salts and azinium salts. Although the specific example of these compounds is shown below, it is not limited to this.

  As an example of the iodonium salt, a diphenyl iodonium salt is preferable, and a diphenyl iodonium salt substituted with an electron donating group such as an alkyl group or an alkoxyl group is particularly preferable, and an asymmetric diphenyl iodonium salt is more preferable. Specific examples include diphenyliodonium = hexafluorophosphate, 4-methoxyphenyl-4- (2-methylpropyl) phenyliodonium = hexafluorophosphate, 4- (2-methylpropyl) phenyl-p-tolyliodonium = hexa. Fluorophosphate, 4-hexyloxyphenyl-2,4,6-trimethoxyphenyliodonium = hexafluorophosphate, 4-hexyloxyphenyl-2,4-diethoxyphenyliodonium = tetrafluoroborate, 4-octyloxy Phenyl-2,4,6-trimethoxyphenyliodonium = 1-perfluorobutanesulfonate, 4-octyloxyphenyl-2,4,6-trimethoxyphenyliodonium = hexafluorophosphate, bis ( -t- butylphenyl) iodonium tetraphenylborate and the like.

  Examples of sulfonium salts include triphenylsulfonium = hexafluorophosphate, triphenylsulfonium = benzoylformate, bis (4-chlorophenyl) phenylsulfonium = benzoylformate, bis (4-chlorophenyl) -4-methylphenylsulfonium = Examples thereof include tetrafluoroborate, tris (4-chlorophenyl) sulfonium = 3,5-bis (methoxycarbonyl) benzenesulfonate, and tris (4-chlorophenyl) sulfonium = hexafluorophosphate.

  Examples of azinium salts include 1-cyclohexylmethyloxypyridinium = hexafluorophosphate, 1-cyclohexyloxy-4-phenylpyridinium = hexafluorophosphate, 1-ethoxy-4-phenylpyridinium = hexafluorophosphate, 1-cyclohexyl (2-ethylhexyloxy) -4-phenylpyridinium = hexafluorophosphate, 4-chloro-1-cyclohexylmethyloxypyridinium = hexafluorophosphate, 1-ethoxy-4-cyanopyridinium = hexafluorophosphate, 3,4 -Dichloro-1- (2-ethylhexyloxy) pyridinium = hexafluorophosphate, 1-benzyloxy-4-phenylpyridinium = hexafluorophosphate, 1-phenethylo Ci-4-phenylpyridinium = hexafluorophosphate, 1- (2-ethylhexyloxy) -4-phenylpyridinium = p-toluenesulfonate, 1- (2-ethylhexyloxy) -4-phenylpyridinium = perfluorobutanesulfonate 1- (2-ethylhexyloxy) -4-phenylpyridinium bromide, 1- (2-ethylhexyloxy) -4-phenylpyridinium tetrafluoroborate.

  The polymerization initiator is preferably added in an amount of 0.1 to 50% by mass, more preferably 0.5 to 30% by mass, and particularly preferably 0.8 to 20% by mass with respect to the total solid content of the image recording layer. be able to. Within this range, better sensitivity and better stain resistance of the non-image area during printing can be obtained.

<Radically polymerizable compound>
The radical polymerizable compound used in the present invention is an addition polymerizable compound having at least one ethylenically unsaturated double bond, and is selected from compounds having at least one terminal ethylenically unsaturated bond, preferably two or more. It is. These have chemical forms such as monomers, prepolymers, ie dimers, trimers and oligomers, or mixtures thereof.

  Examples of monomers include unsaturated carboxylic acids (for example, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid, etc.), esters and amides thereof, preferably unsaturated carboxylic acids. An ester of an acid and a polyhydric alcohol compound and an amide of an unsaturated carboxylic acid and a polyvalent amine compound are used. In addition, an addition reaction product of an unsaturated carboxylic acid ester or amide having a nucleophilic substituent such as a hydroxy group, an amino group or a mercapto group with a monofunctional or polyfunctional isocyanate or epoxy, and a monofunctional or polyfunctional compound. 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 In addition, a substitution reaction product of an unsaturated carboxylic acid ester or amide having a leaving substituent such as a tosyloxy group and a monofunctional or polyfunctional alcohol, amine or thiol is also suitable.

  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. These are disclosed in JP-T-2006-508380, JP-A-2002-287344, JP-A-2008-256850, JP-A-2001-342222, JP-A-9-179296, JP-A-9-179297. JP-A-9-179298, JP-A-2004-294935, JP-A-2006-243493, JP-A-2002-275129, JP-A-2003-64130, JP-A-2003-280187, It is described in references including Kaihei 10-333321.

  Specific examples of the monomer of the ester of a polyhydric alcohol compound and an unsaturated carboxylic acid include acrylic acid esters such as ethylene glycol diacrylate, 1,3-butanediol diacrylate, tetramethylene glycol diacrylate, propylene glycol diacrylate, Examples include trimethylolpropane triacrylate, hexanediol diacrylate, tetraethylene glycol diacrylate, pentaerythritol tetraacrylate, sorbitol triacrylate, isocyanuric acid ethylene oxide (EO) -modified triacrylate, and polyester acrylate oligomer. Methacrylic acid esters include tetramethylene glycol dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpropane trimethacrylate, ethylene glycol dimethacrylate, pentaerythritol trimethacrylate, bis [p- (3-methacryloxy-2-hydroxypropoxy) phenyl ] Dimethylmethane, bis- [p- (methacryloxyethoxy) phenyl] dimethylmethane, and the like. Specific examples of amide monomers of polyvalent amine compounds and unsaturated carboxylic acids include methylene bis-acrylamide, methylene bis-methacrylamide, 1,6-hexamethylene bis-acrylamide, 1,6-hexamethylene bis-methacrylic. Examples include amide, diethylenetriamine trisacrylamide, xylylene bisacrylamide, and xylylene bismethacrylamide.

In addition, urethane-based addition-polymerizable compounds produced by using an addition reaction between an isocyanate and a hydroxy group are also suitable, and specific examples thereof include, for example, one molecule described in Japanese Patent Publication No. 48-41708. A vinyl containing two or more polymerizable vinyl groups in one molecule obtained by adding a vinyl monomer containing a hydroxy group represented by the following general formula (b) to a polyisocyanate compound having two or more isocyanate groups. A urethane compound etc. are mentioned.
^{_{CH 2 = C (R 4)}} COOCH 2 CH (R 5) OH (b)
(However, R ⁴ and R ⁵ represent H or CH _3. )

  Also, urethanes described in JP-A-51-37193, JP-B-2-32293, JP-B-2-16765, JP-A-2003-344997, and JP-A-2006-65210. Acrylates, JP-B 58-49860, JP-B 56-17654, JP-B 62-39417, JP-B 62-39418, JP-A 2000-250211, JP-A 2007-94138 Urethane compounds having an ethylene oxide-based skeleton described in the publication, and urethane compounds having a hydrophilic group described in US Pat. No. 7,153,632, JP-T 8-505958, JP-A 2007-293221, and JP-A 2007-293223. Are also suitable.

  Among them, tris (acryloyloxyethyl) isocyanurate, bis (acryloyloxyethyl) hydroxyethyl isocyanurate, etc. are excellent in the balance between the hydrophilicity involved in on-press developability and the polymerization ability involved in printing durability. Isocyanuric acid ethylene oxide modified acrylates are particularly preferred.

  Details of the method of use such as the structure of these radically polymerizable compounds, whether they are used alone or in combination, and the amount added can be arbitrarily set in accordance with the performance design of the final lithographic printing plate precursor. The polymerizable compound is preferably used in the range of 5 to 75% by mass, more preferably 10 to 70% by mass, and particularly preferably 15 to 60% by mass with respect to the total solid content of the image recording layer.

Organic Fine Particles In the present invention, organic fine particles can be contained in the image recording layer in order to improve on-press developability. The organic fine particles in the present invention are at least selected from hydrophobic thermoplastic polymer fine particles, thermoreactive polymer fine particles, polymer fine particles having a polymerizable group, microcapsules enclosing a hydrophobic compound, and microgel (crosslinked polymer fine particles). One is preferable. Among these, polymer fine particles and microgels having a polymerizable group are preferable. The organic fine particles in the present invention may be discrete particles of the polymer compound of the present invention, and in a particularly preferred embodiment, the organic fine particles contain at least one ethylenically unsaturated polymerizable group. Due to the presence of such organic fine particles, an effect of improving the printing durability of the exposed portion and the on-press developability of the unexposed portion can be obtained.

Hydrophobic thermoplastic polymer fine particles include Research Disclosure No. 1 of January 1992. 331,003, JP-A-9-123387, JP-A-9-131850, JP-A-9-171249, JP-A-9-171250 and European Patent No. 931647 are suitable. Can be cited as
Specific examples of polymers constituting such polymer fine particles include ethylene, styrene, vinyl chloride, methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, vinylidene chloride, acrylonitrile, vinyl carbazole, and polyalkylene structures. Mention may be made of homopolymers or copolymers of monomers such as acrylates or methacrylates or mixtures thereof. Among them, more preferable examples include a copolymer containing polystyrene, styrene and acrylonitrile, and polymethyl methacrylate.
The average particle size of the hydrophobic thermoplastic polymer fine particles used in the present invention is preferably 0.01 to 3.0 μm.

  Examples of the heat-reactive polymer fine particles used in the present invention include polymer fine particles having a heat-reactive group, and these form a hydrophobized region by crosslinking due to a heat reaction and a functional group change at that time.

  The thermoreactive group in the polymer fine particles having a thermoreactive group used in the present invention may be any functional group that performs any reaction as long as a chemical bond is formed, but is preferably a polymerizable group, Examples include ethylenically unsaturated groups that undergo radical polymerization reactions (eg, acryloyl groups, methacryloyl groups, vinyl groups, allyl groups, etc.), cationic polymerizable groups (eg, vinyl groups, vinyloxy groups, epoxy groups, oxetanyl groups, etc.) ), An isocyanate group that performs an addition reaction or a block thereof, an epoxy group, a vinyloxy group, and a functional group having an active hydrogen atom that is a reaction partner thereof (for example, an amino group, a hydroxy group, a carboxy group, etc.), a condensation reaction Carboxy group to be carried out and reaction partner hydroxy group or amino group, acid anhydride to carry out ring-opening addition reaction and reaction An amino group or a hydroxyl group a manual may be mentioned as suitable.

  As the microcapsules used in the present invention, for example, as described in JP-A Nos. 2001-277740 and 2001-277742, all or part of the constituent components of the image recording layer are encapsulated in the microcapsules. Is. The constituent components of the image recording layer can also be contained outside the microcapsules. Furthermore, it is preferable that the image recording layer containing the microcapsule includes a hydrophobic constituent component in the microcapsule and a hydrophilic constituent component outside the microcapsule.

  In this invention, the aspect containing a crosslinked resin particle, ie, a microgel, may be sufficient. This microgel can contain a part of the constituent components of the image recording layer in at least one of the inside and the surface thereof, and in particular, an embodiment in which a reactive microgel is formed by having a radical polymerizable group on the surface thereof, This is particularly preferable from the viewpoint of image formation sensitivity and printing durability.

  As a method for microencapsulating or microgelling the constituent components of the image recording layer, known methods can be applied.

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

  The organic fine particle content is preferably in the range of 5 to 90% by mass of the total solid content of the image recording layer.

Other Components The image recording layer in the invention can further contain other components as necessary.

(1) Low molecular weight hydrophilic compound The image recording layer in the invention may contain a low molecular weight hydrophilic compound in order to improve the on-press developability without reducing the printing durability.
As the low molecular weight hydrophilic compound, for example, as the water-soluble organic compound, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol and the like glycols and ether or ester derivatives thereof, glycerin, Polyols such as pentaerythritol and tris (2-hydroxyethyl) isocyanurate, organic amines such as triethanolamine, diethanolamine and monoethanolamine and salts thereof, organic sulfones such as alkylsulfonic acid, toluenesulfonic acid and benzenesulfonic acid Acids and salts thereof, organic sulfamic acids such as alkylsulfamic acid and salts thereof, organic sulfuric acids such as alkylsulfuric acid and alkylethersulfuric acid and salts thereof, phenylphosphonic acid Organic phosphonic acids and salts thereof, tartaric acid, oxalic acid, citric acid, malic acid, lactic acid, gluconic acid, organic carboxylic acids and salts thereof such as amino acids, betaines, and the like.

  Among these, in the present invention, it is preferable to contain at least one selected from the group consisting of polyols, organic sulfates, organic sulfonates, and betaines.

  Specific examples of organic sulfonates include alkyl sulfonates such as sodium n-butyl sulfonate, sodium n-hexyl sulfonate, sodium 2-ethylhexyl sulfonate, sodium cyclohexyl sulfonate, and sodium n-octyl sulfonate. Sodium 5,8,11-trioxapentadecane-1-sulfonate, sodium 5,8,11-trioxaheptadecane-1-sulfonate, 13-ethyl-5,8,11-trioxaheptadecane-1; Alkyl sulfonates containing ethylene oxide chains such as sodium sulfonate, 5,8,11,14-tetraoxatetradecosane-1-sodium sulfonate; sodium benzenesulfonate, sodium p-toluenesulfonate, p-hydroxy Benzenesulfo Acid sodium, sodium p-styrenesulfonate, sodium dimethyl-5-sulfonate isophthalate, sodium 1-naphthylsulfonate, sodium 4-hydroxynaphthylsulfonate, disodium 1,5-naphthalenedisulfonate, 1,3,6 -Aryl sulfonates such as trisodium naphthalene trisulfonate, paragraph numbers [0026] to [0031] of JP 2007-276454 A, and paragraph numbers [0020] to [0047] of JP 2009-154525 A And the compounds described. The salt may be a potassium salt or a lithium salt.

  Organic sulfates include sulfates of alkyl, alkenyl, alkynyl, aryl or heterocyclic monoethers of polyethylene oxide. The number of ethylene oxide units is preferably 1 to 4, and the salt is preferably a sodium salt, potassium salt or lithium salt. Specific examples thereof include compounds described in paragraph numbers [0034] to [0038] of JP-A-2007-276454.

  As the betaines, compounds having 1 to 5 carbon atoms of the hydrocarbon substituent on the nitrogen atom are preferable. Specific examples include trimethylammonium acetate, dimethylpropylammonium acetate, 3-hydroxy-4-trimethyl. Ammonioobylate, 4- (1-pyridinio) butyrate, 1-hydroxyethyl-1-imidazolioacetate, trimethylammonium methanesulfonate, dimethylpropylammonium methanesulfonate, 3-trimethylammonio-1-propanesulfonate, Examples include 3- (1-pyridinio) -1-propanesulfonate.

  The above low molecular weight hydrophilic compound has a small hydrophobic part structure and almost no surface-active action, so that dampening water penetrates into the exposed part of the image recording layer (image part) and the hydrophobicity and film strength of the image part. Ink acceptability and printing durability of the image recording layer can be maintained satisfactorily.

The amount of these low molecular weight hydrophilic compounds added to the image recording layer is preferably 0.5% by mass or more and 20% by mass or less of the total solid content of the image recording layer. More preferably, they are 1 mass% or more and 15 mass% or less, More preferably, they are 2 mass% or more and 10 mass% or less. In this range, good on-press developability and printing durability can be obtained.
These compounds may be used alone or in combination of two or more.

(2) Grease Sensitizer In the image recording layer of the present invention, a lipid sensitizer such as a phosphonium compound, a nitrogen-containing low molecular weight compound, or an ammonium group-containing polymer is used for the image recording layer in order to improve the inking property. be able to. In particular, when an inorganic layered compound is contained in the protective layer, these compounds function as a surface coating agent for the inorganic layered compound, and prevent a decrease in the inking property during printing by the inorganic layered compound.

  Suitable phosphonium compounds include phosphonium compounds described in JP-A-2006-297907 and JP-A-2007-50660. Specific examples include tetrabutylphosphonium iodide, butyltriphenylphosphonium bromide, tetraphenylphosphonium bromide, 1,4-bis (triphenylphosphonio) butanedi (hexafluorophosphate), 1,7-bis (tri Phenylphosphonio) heptane sulfate, 1,9-bis (triphenylphosphonio) nonane = naphthalene-2,7-disulfonate, and the like.

  Examples of the nitrogen-containing low molecular weight compound include amine salts and quaternary ammonium salts. Also included are imidazolinium salts, benzoimidazolinium salts, pyridinium salts, and quinolinium salts. Of these, quaternary ammonium salts and pyridinium salts are preferable. Specific examples include tetramethylammonium = hexafluorophosphate, tetrabutylammonium = hexafluorophosphate, dodecyltrimethylammonium = p-toluenesulfonate, benzyltriethylammonium = hexafluorophosphate, benzyldimethyloctylammonium = hexafluorophosphate. Fert, benzyldimethyldodecyl ammonium = hexafluorophosphate, paragraph numbers [0021] to [0037] of JP-A-2008-284858, paragraph numbers [0030] to [0057] of JP-A-2009-90645 Compound etc. are mentioned.

  The ammonium group-containing polymer may be any polymer as long as it has an ammonium group in its structure, but a polymer containing 5 to 80 mol% of a (meth) acrylate having an ammonium group in the side chain as a copolymerization component is preferable. . Specific examples include the polymers described in paragraph numbers [0089] to [0105] of JP2009-208458A.

  The ammonium salt-containing polymer has a reduced specific viscosity (unit: ml / g) determined by the following measurement method, preferably in the range of 5 to 120, more preferably in the range of 10 to 110, 15 Those in the range of ~ 100 are particularly preferred. When the said reduced specific viscosity is converted into a mass mean molar mass (Mw), 10,000-150,000 are preferable, 17000-140000 are more preferable, 20000-130000 are especially preferable.

<Measurement method of reduced specific viscosity>
Weigh 3.33 g of 30% polymer solution (1 g as solid content) into a 20 ml volumetric flask and make up with N-methylpyrrolidone. This solution is allowed to stand for 30 minutes in a thermostatic bath at 30 ° C., put in an Ubbelohde reduced viscosity tube (viscosity constant = 0.010 cSt / s), and the time for flowing down at 30 ° C. is measured. The measurement is performed twice with the same sample, and the average value is calculated. Similarly, in the case of a blank (only N-methylpyrrolidone), the reduced specific viscosity (ml / g) was calculated from the following formula.

Specific examples of the ammonium group-containing polymer are shown below.
(1) 2- (Trimethylammonio) ethyl methacrylate = p-toluenesulfonate / 3,6-dioxaheptyl methacrylate copolymer (molar ratio 10/90 Mw 45,000)
(2) 2- (Trimethylammonio) ethyl methacrylate = hexafluorophosphate / 3,6-dioxaheptyl methacrylate copolymer (molar ratio 20/80 Mw 60,000)
(3) 2- (Ethyldimethylammonio) ethyl methacrylate = p-toluenesulfonate / hexyl methacrylate copolymer (molar ratio 30/70 Mw 45,000)
(4) 2- (Trimethylammonio) ethyl methacrylate = hexafluorophosphate / 2-ethylhexyl methacrylate copolymer (molar ratio 20/80 Mw 60,000)
(5) 2- (Trimethylammonio) ethyl methacrylate = methyl sulfate / hexyl methacrylate copolymer (molar ratio 40/60 Mw 7 million)
(6) 2- (Butyldimethylammonio) ethyl methacrylate = hexafluorophosphate / 3,6-dioxaheptyl methacrylate copolymer (molar ratio 25/75 Mw 650,000)
(7) 2- (Butyldimethylammonio) ethyl acrylate = hexafluorophosphate / 3,6-dioxaheptyl methacrylate copolymer (molar ratio 20/80 Mw 65,000)
(8) 2- (butyldimethylammonio) ethyl methacrylate = 13-ethyl-5,8,11-trioxa-1-heptadecanesulfonate / 3,6-dioxaheptyl methacrylate copolymer (molar ratio 20/80 Mw 75,000)
(9) 2- (butyldimethylammonio) ethyl methacrylate = hexafluorophosphate / 3,6-dioxaheptyl methacrylate / 2-hydroxy-3-methacryloyloxypropyl methacrylate copolymer (molar ratio 15/80/5 (Mw 650,000)

  The content of the sensitizer is preferably 0.01 to 30.0% by mass, more preferably 0.1 to 15.0% by mass and 1 to 10% by mass with respect to the total solid content of the image recording layer. Is more preferable.

(3) Others Further, as other components, surfactants, colorants, print-out agents, polymerization inhibitors, higher fatty acid derivatives, plasticizers, inorganic fine particles, inorganic layered compounds, co-sensitizers or chain transfer agents, etc. Can be added. Specifically, paragraph numbers [0114] to [0159] of Japanese Patent Application Laid-Open No. 2008-284817, paragraph numbers [0023] to [0027] of Japanese Patent Application Laid-Open No. 2006-091479, and US Patent Publication No. 2008/0311520. The compound and the addition amount described in paragraph [0060] of FIG.

Formation of Image Recording Layer The image recording layer in the present invention is prepared by dispersing the necessary components described above in known solvents as described in paragraph numbers [0142] to [0143] of JP-A-2008-195018, for example. It is formed by dissolving to prepare a coating solution, coating this on a support by a known method such as bar coater coating, and drying. The image recording layer coating amount (solid content) on the support obtained after coating and drying varies depending on the application, but is generally preferably 0.3 to 3.0 g / m ² . Within this range, good sensitivity and good film characteristics of the image recording layer can be obtained.

(Undercoat layer)
In the lithographic printing plate precursor according to the invention, an undercoat layer (sometimes referred to as an intermediate layer) is preferably provided between the image recording layer and the support. The undercoat layer enhances the adhesion between the support and the image recording layer in the exposed area, and easily peels off the image recording layer from the support in the unexposed area. Contributes to improvement. In the case of infrared laser exposure, the undercoat layer functions as a heat insulating layer, thereby preventing the heat generated by the exposure from diffusing to the support and reducing the sensitivity.

Specific examples of the compound used for the undercoat layer include silane coupling agents having an addition-polymerizable ethylenic double bond reactive group described in JP-A-10-282679, and JP-A-2- Examples thereof include phosphorus compounds having an ethylenic double bond reactive group described in Japanese Patent No. 304441. More preferable is a polymer resin having an adsorptive group, a hydrophilic group, and a crosslinkable group that can be adsorbed on the surface of the support, as described in JP-A Nos. 2005-125749 and 2006-188038. It is done. The polymer resin is preferably a copolymer of a monomer having an adsorptive group, a monomer having a hydrophilic group, and a monomer having a crosslinkable group. More specifically, a phenolic hydroxyl group, a carboxyl _{group, -PO 3 H 2, -OPO 3} H 2, -CONHSO 2 -, - SO 2 NHSO 2 -, - having an adsorptive group such as COCH 2 COCH ₃ Examples thereof include a polymer resin that is a copolymer of a monomer, a monomer having a hydrophilic sulfo group, and a monomer having a polymerizable crosslinkable group such as a methacryl group or an allyl group. This polymer resin may have a crosslinkable group introduced by salt formation between a polar substituent of the polymer resin, a substituent having a counter charge and a compound having an ethylenically unsaturated bond, Other monomers, preferably hydrophilic monomers, may be further copolymerized.

The content of unsaturated double bonds in the polymer resin for the undercoat layer is preferably 0.1 to 10.0 mmol, and most preferably 2.0 to 5.5 mmol, per 1 g of the polymer resin.
The polymer resin for the undercoat layer preferably has a mass average molar mass of 5000 or more, more preferably 10,000 to 300,000.

  The undercoat layer of the present invention comprises, in addition to the above undercoat compound, a chelating agent, a secondary or tertiary amine, a polymerization inhibitor, an amino group, or a functional group having a polymerization inhibiting ability, in order to prevent contamination over time. Compounds having a group that interacts with the surface of an aluminum support (for example, 1,4-diazabicyclo [2,2,2] octane (DABCO), 2,3,5,6-tetrahydroxy-p-quinone, chloranil , Sulfophthalic acid, hydroxyethylethylenediaminetriacetic acid, dihydroxyethylethylenediaminediacetic acid, hydroxyethyliminodiacetic acid, and the like.

The undercoat layer is applied by a known method. The coating amount (solid content) of the undercoat layer is preferably from 0.1 to 100 mg / m ² , and more preferably from ¹ to 30 mg / m ² .

(Support)
As the support used in the lithographic printing plate precursor according to the invention, a known support is used. Of these, an aluminum plate that has been roughened and anodized by a known method is preferred.
In addition, the above aluminum plate is optionally subjected to micropore enlargement treatment or sealing treatment of an anodized film described in JP-A Nos. 2001-253181 and 2001-322365, and US Pat. 714,066, 3,181,461, 3,280,734 and 3,902,734, or alkali metal silicates as described in U.S. Pat. Surface hydrophilization treatment with polyvinylphosphonic acid or the like as described in each specification of 3,276,868, 4,153,461 and 4,689,272 is appropriately performed and performed. be able to.
The support preferably has a center line average roughness of 0.10 to 1.2 μm.

  If necessary, the support of the present invention includes an organic polymer compound described in JP-A-5-45885 and a silicon alkoxy compound described in JP-A-6-35174 on the back surface. A backcoat layer can be provided.

(Protective layer)
In the lithographic printing plate precursor according to the invention, a protective layer (overcoat layer) is preferably provided on the image recording layer. In addition to the function of suppressing the image formation inhibition reaction by blocking oxygen, the protective layer has a function of preventing scratches in the image recording layer and preventing ablation during high-illuminance laser exposure.

The protective layer having such characteristics is described in, for example, US Pat. No. 3,458,311 and Japanese Patent Publication No. 55-49729. As the low oxygen permeability polymer used for the protective layer, either a water-soluble polymer or a water-insoluble polymer can be appropriately selected and used, and two or more types can be mixed and used as necessary. it can. Specific examples include polyvinyl alcohol, modified polyvinyl alcohol, polyvinyl pyrrolidone, water-soluble cellulose derivatives, poly (meth) acrylonitrile, and the like.
As the modified polyvinyl alcohol, acid-modified polyvinyl alcohol having a carboxy group or a sulfo group is preferably used. Specifically, modified polyvinyl alcohols described in JP-A-2005-250216 and JP-A-2006-259137 are suitable.

Further, in order to enhance the oxygen barrier property, the protective layer preferably contains an inorganic layered compound such as natural mica and synthetic mica as described in JP-A-2005-119273.
Further, the protective layer may contain known additives such as a plasticizer for imparting flexibility, a surfactant for improving coating properties, and inorganic fine particles for controlling surface slipperiness. Further, the protective layer can contain the sensitizer described in the description of the image recording layer.

The protective layer is applied by a known method. The coating amount of the protective layer, the coating amount after drying is preferably in the range of 0.01 to 10 g / ^{m 2,} more preferably in the range of 0.02 to 3 g / ^{m 2,} and most preferably 0. in the range of 02~1g / ^{m 2.}

[Cutting conditions and edge shape of planographic printing plate precursor]
FIG. 1 is an example of a cross-sectional shape of an end portion of a lithographic printing plate precursor cut by a cutting device. The vertical distance X of the portion bent downward from the extended line of the image recording layer surface is referred to as “sag amount”. In the lithographic printing plate precursor developed with an alkali developer, no residual film is generated during development regardless of the value of X. However, in the case of an on-press development type lithographic printing plate precursor, depending on the value of X, the cut edge portion during development Residual film is generated. From the viewpoint of this remaining film, the preferable range of X is 25 μm or less. When X exceeds 25 μm, a residual film is generated during on-press development, and thick linear stains (called frame stains or linear stains) are generated at the edges of the printed matter.
A more preferable range in which no residual film is generated at the end is 20 μm or less, particularly preferably 10 μm or less.
The reason why a smaller amount of sagging is preferable for the remaining film at the end in on-press development is estimated as follows. The unexposed portion of the image recording layer is removed by physical contact between the blanket of the printing press and the image recording layer, in addition to the penetration, swelling, and dissolving action of at least one of ink and fountain solution. However, if the sagging amount exceeds 25 μm, the contact between the blanket and the image recording layer at the end sagging portion becomes weak, and it is considered that the image recording layer is not rubbed off and a remaining film is formed.
However, when the sagging amount is 0 to 1 μm, the on-press developability is good and there is no remaining film, but the printed matter in the portion corresponding to the edge is thinly stained in a linear shape. This is presumed that when the edge portion is not dripped at all or the amount of dripping is smaller than 1 μm, the printing ink component repelled from the non-image portion to the edge portion is easily transferred to the blanket, causing smudges on the printed matter. .

(Means for obtaining the shape of FIGS. 1 and 2)
A detailed method for producing the shape of FIG. 1 will be described. FIG. 3 is a cross-sectional view showing a cutting portion of the slitter device. In the slitter device, a pair of upper and lower cutting blades 10 and 20 are arranged on the left and right. These cutting blades 10 and 20 are circular blades on a circular plate, and the upper cutting blades 10a and 10b are supported on the rotating shaft 11 and the lower cutting blades 20a and 20b are supported on the rotating shaft 21 on the same axis. The upper cutting blades 10a and 10b and the lower cutting blades 20a and 20b are rotated in opposite directions. The aluminum sheet 30 is passed between the upper cutting blades 10a and 10b and the lower cutting blades 20a and 20b and cut into a predetermined width. More specifically, by adjusting the gap between the upper cutting blade 10a and the lower cutting blade 20a and the gap between the upper cutting blade 10b and the lower cutting blade 20b in the cutting section of the slitter device of FIG. An end portion having a shape as shown in FIG.

  Next, a general method for producing the shape of FIG. 2 will be described. When using a shearing force type cutting machine having a cutting blade of 30 to 60 ° above and below, specifically a shearing type punching machine or a guillotine shear having such a cutting blade, the occurrence of flash and sag can be suppressed as much as possible. . In particular, when the image recording layer surface is directed downward and a shearing type punching machine or a guillotine shear is used, a sample having a shape without sagging in FIG. 2 can be produced. However, even when a shearing type punching machine or a guillotine shear is used, the shape shown in FIG. 1 can be obtained by adjusting the gap between the stand on which the plate is placed and the blade edge. The gap between the table on which the plate is placed and the blade edge depends on the condition of the blade, but is usually preferably 0 to 100 μm. The larger the gap, the larger the sagging amount.

(Bundling)
Next, a method for cutting in a bundle state will be described. The bundle cutting machine shown in FIG. 4 is configured to cut the laminated bundle 12 by lowering the cutting blade 202 while slightly swinging it.
The cutting blade 202 is configured by attaching steel 206 to the tip of the base material 204. The base material 204 is made of carbon steel for mechanical structure S45C / S55C (JISG4051) or rolled steel for general structure SS400 (JISG3101), and the material of the steel 206 is high-speed tool steel SKH51 (JISG4403) or Alloy tool steel SKD11 (JIS G4404), which is brazed to a base material with a brazing material mainly composed of a metal such as silver or copper. Further, as the material of the steel 206, a powdered metal raw material is mixed and then manufactured (consolidated) by powder metallurgy, and a cemented carbide having a uniform and fine carbide structure, powder high-speed tool steel, powder alloy tool Steel or the like may be used. In particular, the cemented carbide is similar to the general alloy tool steel SKD11 in the V10 to V60 described in the cemented carbide tool association CIS019C “Cemented carbide grade selection criteria for wear resistant tools” and powder alloy tool steel. The chemical component may have a higher chromium content. Furthermore, the hardness of the steel 206 is 73 to 95 in Shore hardness (JISZ2246), and the steel in which the powder raw material is sintered is HV600 to 1800 in Picker's hardness (JISZ2244). The thickness is 80 mm and the thickness is 2 to 6 mm (mainly 3 mm).

  An inclined cutting edge surface 206A is formed on the front side of the steel 206, and a slightly inclined cutting edge kill surface (not shown) is formed on the back side thereof. With this blade edge killing surface, even freshly ground steel 206 is difficult to spill and can be cut in a stable state from the beginning, and burrs are reduced at the corners of the cut surface. On the back surface of steel 206, a carbon film having an amorphous structure of Picker's scrap hardness (JISZ2244) 3000 to 5000 is deposited by ion plating (not shown), and the so-called diamond-like film thickness is 0.3 to 3 μm. A coating film called carbon (DLC) is formed. By reducing the metal affinity with the cutting surface of the lithographic printing plate precursor by coating in this way, it becomes difficult for chips to adhere to the steel 206 (because it is difficult to generate a cutting edge), so the quality of the cutting surface is good Thus, the life of the cutting blade 202 is extended.

  The bundle cutting machine configured as described above first stacks 1 to 10 laminated bundles 12 on a cradle 210 and pushes the laminated bundle 12 until it hits the back gauge 208. The laminated bundle 12 is pressed by the clamp 207 to which a force of 4 to 6 tons is applied, and the cutting blade 202 is pushed down (while swinging). Then, the blade is pushed in until the cutting edge hits the cradle 210 (or the batten embedded in the cradle). Thereby, the laminated bundle 12 is cut by the cutting edge surface 206 </ b> A of the steel 206. Therefore, the cut surface does not become uneven, and the laminated bundle 12 can be neatly cut. The bundle cutting of the master sheet stack 12 is performed until the required product size is obtained.

〔Processing method〕
As an aspect of applying the treatment liquid to the lithographic printing plate precursor of the present invention, the treatment liquid can be applied to the side of the lithographic printing plate precursor one by one, or a large number (for example, 1000) of lithographic printing plates You may apply | coat to the side surface in the state which accumulated the original edition. In this case, for example, it is of course possible to apply the paper while sandwiching a slip sheet as described in Japanese Patent Publication Nos. 57-23259 and 57-99647. Also preferred is a method in which, after continuous cutting with a slitter or a bundle cutter, the coating is immediately applied with a Molton roll containing the treatment liquid used in the present invention. After the application, they are stacked in a setter stocker and exposed.
Alternatively, the treatment liquid may be applied to each sheet after imagewise exposure of an infrared laser by a setter. If the coating is performed after image exposure, the plates after coating are not stacked, and sticking of each plate due to stickiness does not occur. The side surface is applied within 1 cm from the end, preferably within 0.5 cm, and most preferably within 0.2 cm. There is usually no image within 1 cm from the edge.
The thickness applied to the end is preferably 0.1 to 50 μm, more preferably 1 to 25 μm after the treatment liquid is dried. Within this range, good on-press developability can be obtained without sticking between the plate and the coated portion.

[Plate making]
Plate making of the lithographic printing plate precursor according to the invention is carried out by an on-press development method. The on-press development method includes an image exposure process for a lithographic printing plate precursor, a printing process in which an oil-based ink and an aqueous component are supplied and printed without performing any development process on the exposed lithographic printing plate precursor. The image recording layer unexposed portion of the lithographic printing plate precursor is removed in the course of the printing process. Imagewise exposure may be performed on the printing machine after the lithographic printing plate precursor is mounted on the printing machine, or may be separately performed with a plate setter or the like. In the latter case, the exposed lithographic printing plate precursor is mounted on a printing machine without undergoing a development process. Thereafter, by using the printing machine and supplying the oil-based ink and the aqueous component and printing as it is, an on-press development process, that is, an image recording layer in an unexposed area is removed at an early stage of printing, Accordingly, the surface of the hydrophilic support is exposed to form a non-image part. As the oil-based ink and the aqueous component, printing ink and dampening water for newspaper lithographic printing are used.

In the present invention, the light source used for image exposure is preferably a laser. Although the laser used for this invention is not specifically limited, The solid laser and semiconductor laser etc. which irradiate infrared rays with a wavelength of 760-1200 nm are mentioned suitably.
Regarding the infrared laser, the output is preferably 100 mW or more, the exposure time per pixel is preferably within 20 microseconds, and the irradiation energy amount is preferably 10 to 300 mJ / cm ² . In the laser, it is preferable to use a multi-beam laser device in order to shorten the exposure time.

  The exposed lithographic printing plate precursor is mounted on a plate cylinder of a printing press. In the case of a printing press equipped with a laser exposure device, image exposure is performed after a lithographic printing plate precursor is mounted on a plate cylinder of the printing press.

  When printing is performed by supplying dampening water and printing ink to the lithographic printing plate precursor exposed imagewise, the image recording layer cured by exposure has a printing ink acceptance having an oleophilic surface in the exposed portion of the image recording layer. Forming part. On the other hand, in the unexposed area, the uncured image recording layer is removed by dissolution or dispersion by the supplied dampening water and / or printing ink, and a hydrophilic surface is exposed in that area. As a result, the fountain solution adheres to the exposed hydrophilic surface, and the printing ink is deposited on the image recording layer in the exposed area and printing is started.

  Here, dampening water or printing ink may be supplied to the printing plate first, but printing is first performed in order to prevent the dampening water from being contaminated by the removed image recording layer components. It is preferable to supply ink.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these. The molecular weight of the polymer compound is a mass average molecular weight, and the ratio of repeating units is a molar ratio.

[Examples 1 to 25 and Comparative Examples 1 to 5]

[Preparation of lithographic printing plate precursors (1) to (13)]
(1) Production of support (part 1)
In order to remove rolling oil on the surface of an aluminum plate (material JIS A 1050) having a thickness of 0.3 mm, 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 adjusted to 0. The aluminum surface was grained using ^three 3 mm bundled nylon brushes and a pumice-water suspension (specific gravity 1.1 g / cm ³ ) having a median diameter of 25 μm and washed well 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.

Subsequently, nitric acid electrolysis was performed with an aqueous solution of 0.5% by mass of hydrochloric acid (containing 0.5% by mass of aluminum ions) and an electrolytic solution having a liquid temperature of 50 ° C. under the condition of an electric quantity of 50 C / dm ² when the aluminum plate was the anode. Electrochemical surface roughening treatment was carried out in the same manner as above, followed by washing with water by spraying.
Next, the plate was provided with a direct current anodic oxide film having a current density of 15 A / dm ² and a current density of 15 g / m ² using 15% by mass sulfuric acid (containing 0.5% by mass of aluminum ions) as an electrolytic solution, followed by washing with water. It dried and produced the support body (1).
Thereafter, in order to ensure the hydrophilicity of the non-image area, the support (1) was subjected to a silicate treatment at 60 ° C. for 10 seconds using an aqueous 2.5 mass% No. 3 sodium silicate solution, and then washed with water for support. Body (2) was obtained. The adhesion amount of Si was 10 mg / m ² . The centerline average roughness (Ra) of this substrate was measured using a needle having a diameter of 2 μm and found to be 0.51 μm.

(2) Formation of undercoat layer Next, the following undercoat layer coating solution (1) is applied onto the support (2) so that the dry coating amount is 20 mg / m ² , and used in the following experiments. A support having a layer was prepared.

<Coating liquid for undercoat layer (1)>
-Undercoat layer compound (1) having the following structure: 0.18 g
・ Hydroxyethyliminodiacetic acid 0.10g
・ Methanol 55.24g
・ Water 6.15g

(3) Formation of image recording layer The image recording layer coating solution (1) having the following composition was bar-coated on the undercoat layer formed as described above, and then oven-dried at 100 ° C for 60 seconds to obtain a dry coating amount. An image recording layer of 1.0 g / m ² was formed. In the case of the lithographic printing plate precursor (11), an image recording layer was directly coated on the support (2) without providing an undercoat layer.
The image recording layer coating solution (1) was obtained by mixing and stirring the following photosensitive solution (1) and microgel solution (1) immediately before coating.

<Photosensitive solution (1)>
・ Specific polymer compound (binder) [type and amount added are listed in Table 1]
Infrared absorbing dye (1) [the following structure] 0.030 g
-Radical polymerization initiator (1) [the following structure] 0.162 g
・ Radically polymerizable compound 0.339g
Tris (acryloyloxyethyl) isocyanurate (NK ester A-9300, manufactured by Shin-Nakamura Chemical Co., Ltd.)
・ Low molecular weight hydrophilic compound (1) [the following structure] 0.050 g
-Sensitizing agent Phosphonium compound (1) [the following structure] 0.055 g
・ Fluorosurfactant (1) [The following structure] 0.008g
・ 2-butanone 1.091g
・ 1-methoxy-2-propanol 8.609g

<Microgel solution (1)>
・ Microgel (1) 2.640 g
・ Distilled water 2.425g

  Structure of polymerization initiator (1), infrared absorbing dye (1), low molecular weight hydrophilic compound (1), phosphonium compound (1) and fluorine-based surfactant (1) and method for synthesizing microgel (1) Is as follows.

-Synthesis of microgel (1)-
As an oil phase component, trimethylolpropane and xylene diisocyanate adduct (Mitsui Chemical Polyurethane Co., Ltd., Takenate D-110N) 10 g, pentaerythritol triacrylate (Nippon Kayaku Co., Ltd., SR444) 3.15 g, And 0.1 g of Pionein A-41C (manufactured by Takemoto Yushi Co., Ltd.) was dissolved in 17 g of ethyl acetate. As an aqueous phase component, 40 g of a 4% by mass aqueous solution of PVA-205 was prepared. The oil phase component and the aqueous phase component were mixed and emulsified for 10 minutes at 12,000 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 50 ° C. for 3 hours. The microgel solution thus obtained was diluted with distilled water to a solid content concentration of 15% by mass, and this was designated as the microgel (1). When the average particle size of the microgel was measured by a light scattering method, the average particle size was 0.2 μm.

(4) Formation of protective layer After the bar coating of the protective layer coating solution (1) having the following composition was further applied on the image recording layer, it was oven-dried at 120 ° C. for 60 seconds, and the dry coating amount was 0.15 g / m ^2. A lithographic printing plate precursor (1) to (13) was obtained.

<Coating liquid for protective layer (1)>
・ Inorganic layered compound dispersion (1) 1.5 g
-Polyvinyl alcohol (Nippon Synthetic Chemical Industry Co., Ltd. CKS50, sulfonic acid modification,
Saponification degree 99 mol% or more, polymerization degree 300) 6% by mass aqueous solution 0.55 g
・ Polyvinyl alcohol (PVA-405 manufactured by Kuraray Co., Ltd.)
Degree of saponification 81.5 mol%, degree of polymerization 500) 6% by weight aqueous solution 0.03 g
・ Nippon Emulsion Co., Ltd. surfactant (Emalex 710) 1% by weight aqueous solution 0.86g
・ Ion-exchanged water 6.0g

(Preparation of inorganic layered compound dispersion (1))
6.4 g of synthetic mica Somasif ME-100 (manufactured by Coop Chemical Co., Ltd.) was added to 193.6 g of ion-exchanged water, and dispersed using an homogenizer until the average particle size (laser scattering method) became 3 μm. The aspect ratio of the obtained dispersed particles was 100 or more.

[Cutting of lithographic printing plate precursor]
The lithographic printing plate precursor was cut by guillotine shearing and bundling to produce samples with the following sagging amount.

<Cutting by guillotine shear>
In the cutting with a guillotine shear, the following conditions A to F were obtained by adjusting the interval between the upper blade and the table in increments of 1 μm within a range of 0 to 25 μm.

<Bund cutting (Condition G)>
The cutting machine was an erk-115 type manufactured by Itotech Co., Ltd., and the processing blade used was diamond-like carbon processed with a cutting edge of 30 °. A laminated bundle is a bundle of 50 lithographic printing plate precursors, and a protective sheet made of thick paper (generally referred to as a “contact ball”) is placed on the top and bottom, and the surface having the image recording layer faces downward. The sample was placed on a bundle cutting machine and pressed with a clamp applied with a force of 6 t from the upper surface, and then cut to prepare a sample. In the case of producing a bundle of 50 sheets, a sheet in which no interleaf paper was used was produced. The sagging amount of the 25th sample from the top of the bundle was 3 μm.

The shape of the sample was measured with a surface roughness meter (Surfcom) manufactured by Tokyo Seimitsu Co., Ltd. Model No. 480A was used, and a stylus having a diameter of 2 μm was used. 1mm inside the end of the stylus
The shape was measured by moving from the edge toward the edge at a speed of 3 mm / sec.

[Processing of pre-cut lithographic printing plate precursor]
(Processing liquid)
Treatment liquids 1 to 9 were prepared according to the following treatment liquid formulation (1). Also, an emulsification type treatment liquid was prepared as the treatment liquid 10.

<Treatment liquid formulation (1)>
85g of water
Water-soluble resin (described in Table 3) 10g
Organic solvent (described in Table 3) 2.5 g
Phosphoric acid compound (described in Table 3) 2 g
Sodium dodecylbenzenesulfonate 0.5g

<Emulsification type treatment liquid 10>
<Preparation of aqueous phase> Into 676 parts by mass of pure water, 75 parts by mass of grafted starch, 75 parts by mass of cream dextrin, and 60 parts by mass of soybean polysaccharide were added, heated to 80 ° C and then cooled to 40 ° C. Thereafter, 20 parts by mass of primary ammonium phosphate, 5 parts by mass of phosphoric acid (85% by mass), 20 parts by mass of glycerin, 3 parts by mass of magnesium nitrate, 5-chloro-2-methyl-4-isothiazolin-3-one 0 parts by mass was added and dissolved to prepare an aqueous phase.
<Preparation of oil phase> 10 parts by mass of dibutyl sebacate, 10 parts by mass of benzyl alcohol, 15 parts by mass of polyoxyethylene nonylphenyl ether (HLB7.8), 5 parts by mass of polyoxyethylene nonylphenyl ether (HLB11.2), and 25 parts by mass of sodium dialkylsulfosuccinate (70% by mass) was added and stirred until a uniform solution was obtained.
<Emulsification / dispersion> The aqueous phase was adjusted to 40 ° C., and the oil phase was slowly dropped into a stirring speed of 500 to 600 rpm with a three-one motor, followed by further stirring for 10 minutes. Then, it emulsified using the pressure type homogenizer.

<Processing method>
About the sample which carried out the bundle cutting, it apply | coated to the range within 1 cm of an edge part from the edge part by the cloth which included the process liquid in the state of the bundle in the cut surface after cutting.
About the sample cut | judged with the guillotine shear, it apply | coated to the range within 1 cm of an edge part from the edge part with the cloth which included the process liquid before or after exposure.
The thickness after application was 30 μm. The applied thickness was measured in the same manner as the sample shape measurement, and was determined from the difference in sample shape measurement from the value after application.

[Examples 26 to 50 and Comparative Examples 6 to 10]

[Preparation of lithographic printing plate precursors (14) to (26)]
(1) Formation of Image Recording Layer After applying the following image recording layer coating solution (2) to the above support having an undercoat layer, it is oven-dried at 70 ° C. for 60 seconds, and the dry coating amount is 0.6 g. An image recording layer of / m ² was formed.

<Image recording layer coating solution (2)>
・ Specific polymer compound (fine particle shape) [Type and amount added are listed in Table 5]
・ Infrared absorbing dye (2) [The following structure] 0.2g
・ Radical polymerization initiator Irgacure250 (Ciba Specialty Chemicals) 0.5g
・ Radically polymerizable compound SR-399 (Sartomer) 1.50 g
・ Mercapto-3-triazole 0.2g
・ Byk336 (Byk Chimie) 0.4g
・ Klucel M (Hercules) 4.8g
・ ELVACITE 4026 (Ineos Acrylica) 2.5g
・ N-propanol 55.0g
・ 2-butanone 17.0g

In addition, the compounds described by trade names in the above composition are as follows.
IRGACURE 250: (4-methoxyphenyl) [4- (2-methylpropyl) phenyl] iodonium = hexafluorophosphate (75% by mass propylene carbonate solution)
SR-399: Dipentaerythritol pentaacrylate Byk 336: Modified dimethylpolysiloxane copolymer (25% by mass xylene / methoxypropyl acetate solution)
・ Klucel M: Hydroxypropyl cellulose (2 mass% aqueous solution)
ELVACITE 4026: Hyperbranched polymethyl methacrylate (10% by mass 2-butanone solution)

(Production of polymer compound fine particle aqueous dispersion (1))
A 1000 ml four-necked flask was equipped with a stirrer, thermometer, dropping funnel, nitrogen inlet tube, reflux condenser, and nitrogen gas was introduced to perform deoxygenation, while polyethylene glycol methyl ether methacrylate (average of PEGMA ethylene glycol) The repeating unit was 20) 10 g, distilled water 200 g and n-propanol 200 g were added and heated until the internal temperature reached 70 ° C. Next, a premixed mixture of 10 g of styrene (St), 80 g of acrylonitrile (AN) and 0.8 g of 2,2′-azobisisobutyronitrile was added dropwise over 1 hour. After completion of the dropwise addition, the reaction was continued for 5 hours, and then 0.4 g of 2,2′-azobisisobutyronitrile was added to raise the internal temperature to 80 ° C. Subsequently, 0.5 g of 2,2′-azobisisobutyronitrile was added over 6 hours. Polymerization has progressed to 98% or more at the stage of reaction for a total of 20 hours, and a polymer compound fine particle aqueous dispersion (1) having a mass ratio of PEGMA / St / AN = 10/10/80 is obtained. It was. The particle size distribution of the polymer compound fine particles had a maximum value at a particle size of 150 nm.

  Here, the particle size distribution is obtained by taking an electron micrograph of polymer compound fine particles, measuring the total particle size of 5000 particles on the photograph, and between 0 and the maximum value of the obtained particle size measurement value. The frequency of appearance of each particle size was plotted by dividing it into 50 logarithmic scales. For non-spherical particles, the particle size of spherical particles having the same particle area as that on the photograph was used as the particle size.

(Production of polymer compound fine particle aqueous dispersion (2))
Replaced polyethylene glycol methyl ether methacrylate (average 20 PEGMA ethylene glycol repeating unit) with polyethylene glycol methyl ether methacrylate (40 average PEGMA ethylene glycol repeating unit) in the production of polymer fine particle aqueous dispersion (1) Were manufactured in the same way.

(Production of polymer compound fine particle aqueous dispersion (3))
Polyethylene glycol methyl ether methacrylate (average repeat unit of PEGMA ethylene glycol is 20) is replaced with polyethylene glycol methyl ether methacrylate (average repeat unit of PEGMA ethylene glycol is 4) in the production of polymer compound fine particle aqueous dispersion (1) Were manufactured in the same way.

(Production of polymer compound fine particle aqueous dispersion (4))
Replaced polyethylene glycol methyl ether methacrylate (average repeat unit of PEGMA ethylene glycol is 20) with polyethylene glycol methyl ether methacrylate (average repeat unit of PEGMA ethylene glycol is 2) in the production of polymer fine particle aqueous dispersion (1) Were manufactured in the same way.

(Production of polymer compound fine particle aqueous dispersion (5))
Replaced polyethylene glycol methyl ether methacrylate (average repeat unit of PEGMA ethylene glycol is 20) with polyethylene glycol methyl ether methacrylate (average repeat unit of PEGMA ethylene glycol is 90) in the production of polymer fine particle aqueous dispersion (1) Were manufactured in the same way.

(Production of polymer compound fine particle aqueous dispersion (6))
Polyethylene glycol methyl ether methacrylate (the average repeating unit of PEGMA ethylene glycol is 20) in the production of the polymer compound fine particle aqueous dispersion (1) was replaced with ethylene glycol methyl ether methacrylate (EGMA).

(Production of polymer compound fine particle aqueous dispersion (7))
A stirrer, thermometer, dropping funnel, nitrogen inlet tube, reflux condenser is applied to a 1000 ml four-necked flask, and 350 mL of distilled water is added while deoxygenating by introducing nitrogen gas, and the internal temperature becomes 80 ° C. Until heated. 1.5 g of sodium dodecyl sulfate was added as a dispersant, and 0.45 g of ammonium persulfide was added as an initiator, and then 5.0 g of styrene and 40.0 g of acrylonitrile were added dropwise from the dropping funnel over about 1 hour. After the completion of the dropwise addition, the reaction was continued as it was for 5 hours, and then the unreacted monomer was removed by steam distillation. Thereafter, the mixture was cooled and adjusted to pH 6 with ammonia water, and finally pure water was added so that the nonvolatile content was 15% by mass to obtain an aqueous dispersion of polymer compound fine particles (7). The particle size distribution of the polymer compound fine particles measured in the same manner as in the case of the polymer compound fine particle aqueous dispersion (1) had a maximum value at a particle size of 60 nm.

[Cutting and processing of lithographic printing plate precursors]
It carried out similarly to the case of the said lithographic printing plate precursor (1)-(13).

[Evaluation of planographic printing plate precursor]

(1) On-press developability (observation of edge residual film)
The resulting lithographic printing plate precursor was exposed with a Luxel PLASETTER T-6000III manufactured by Fuji Film Co., Ltd. equipped with an infrared semiconductor laser under the conditions of an outer drum rotation speed of 1000 rpm, a laser output of 70%, and a resolution of 2400 dpi.
After exposure, 100,000 pages / hour using Sovibe KKST-S (Red) manufactured by Inktec Co., Ltd. and Toyo ALKY dampening water manufactured by Toyo Ink Co., Ltd. as newspaper ink on an offset rotary printing press. 20,000 sheets were printed at a speed of. The ink of the plate after printing was removed with a cleanser, and the end portion (edge portion) of the plate was observed with an SEM to check for the presence of a remaining film and evaluated according to the following criteria.
○: There is no residual film. Δ: A thin film remains, but acceptable level.
×: The film is clearly left unacceptable. ○ △: Intermediate level between ○ and △.
Δ ×: Intermediate level between Δ and ×.

(2) Edge stain The 1000th printed material of the above printing was sampled, and the degree of linear stain due to the edge portion was evaluated according to the following criteria.
○: Not dirty at all. Δ: Slightly dirty but acceptable level.
×: Clearly dirty and unacceptable level. ○ △: Intermediate level between ○ and △.
Δ ×: Intermediate level between Δ and ×.

(3) Leaving stains on the edge portion After printing 1000 sheets under the above conditions, printing was stopped and the printing plate was left on the printing press cylinder for 1 hour. Thereafter, printing was resumed, and the stain on the edge portion of the 1000th printed material was evaluated based on the same criteria as the above-mentioned edge stain.

(4) Printing durability due to image abrasion After the above-described evaluation of on-press developability, the printing was further continued. As the number of printed sheets was increased, the image recording layer was gradually worn out, so that the ink density on the printed material decreased. Printing durability was evaluated using the number of printed copies when the value measured by the Gretag densitometer for the 50% halftone dot area ratio of the FM screen in the printed material was 5% lower than the measured value for the 100th printed sheet. . The printing durability is acceptable if it is 30,000 sheets or more.
The results are shown in Tables 6 and 7.

[Reference example]
The following two types (S1, S2) of lithographic printing plate precursors were prepared.
(S1) A lithographic printing plate precursor obtained by cutting the lithographic printing plate precursor No. 1 under the condition B with a guillotine shear and treating with the processing solution NO. 1 after exposure, as in Example 3.
(S2) A lithographic printing plate precursor in which the lithographic printing plate precursor No. 1 was cut with a guillotine under condition B, but not treated with a treatment solution after exposure.
Developers obtained by diluting the above two types of lithographic printing plate precursors with DN-3C (alkaline aqueous solution developer manufactured by Fuji Film Co., Ltd.) 1: 1 with water using 800H (Fuji Film Co., Ltd. automatic developing machine) Then, a gum solution obtained by diluting FN-2 (gum solution manufactured by FUJIFILM Corporation) 1: 1 with water was immediately applied and dried to obtain a lithographic printing plate.
When the above lithographic printing plate was evaluated for printing in the same manner as in Example 3, the remaining film, linear stains, and neglected stains were all evaluated as ◯ regardless of whether or not the treatment with the treatment liquid was performed.
From this, it is clear that the present invention solves the problems peculiar to on-press development different from the case of having the conventional development processing.
The printing durability in the above evaluation was 40,000 sheets, which was slightly inferior to the case of on-press development.

DESCRIPTION OF SYMBOLS 10 Cutting blade 10a Upper cutting blade 10b Upper cutting blade 11 Rotating shaft 20 Cutting blade 20a Lower cutting blade 20b Lower cutting blade 21 Rotating shaft 12 Stacked bundle 202 Cutting blade 204 Base material
206 Steel 206A Blade surface 207 Clamp 208 Back gauge 210 Receiving base

Claims (11)

  Infrared absorbing dye, radical polymerization initiator, radical polymerizable compound and polymer compound having polyoxyalkylene chain in the side chain are contained on the support and developed with printing ink and / or dampening water on the cylinder of the printing press. A lithographic printing plate precursor having a possible image recording layer, for newspaper printing obtained by treating a region within 1 cm from the edge of the lithographic printing plate precursor with a liquid containing an organic solvent and a water-soluble resin A lithographic printing plate precursor.   The lithographic printing plate precursor for newspaper printing according to claim 1, wherein the polyoxyalkylene chain of the polymer compound is a polyoxyethylene chain, and the number of repeating units of oxyethylene is 2 to 50.   The lithographic printing plate precursor for newspaper printing according to claim 1 or 2, wherein the polymer compound is polymer compound fine particles.   The lithographic printing plate precursor for newspaper printing according to claim 1 or 2, wherein the polymer compound is a binder.   2. An undercoat layer containing an acidic group adsorbed on the surface of the support and a polymer compound having a radical polymerizable ethylenically unsaturated bond in the side chain between the support and the image recording layer. A lithographic printing plate precursor for newspaper printing according to any one of -4.   The lithographic printing plate precursor for newspaper printing according to any one of claims 1 to 5, wherein the amount of sag at the edge of the lithographic printing plate precursor is 25 µm or less.   The lithographic printing plate precursor for newspaper printing according to any one of claims 1 to 6, wherein the water-soluble resin is a polysaccharide.   The lithographic printing plate precursor for newspaper printing according to any one of claims 1 to 7, wherein the organic solvent is alcohol.   The lithographic printing plate precursor for newspaper printing according to claim 7 or 8, wherein the liquid containing the organic solvent and the water-soluble resin further contains a phosphoric acid compound.   Infrared absorbing dye, radical polymerization initiator, radical polymerizable compound and polymer compound having polyoxyalkylene chain in the side chain are contained on the support and developed with printing ink and / or dampening water on the cylinder of the printing press. A method for producing a lithographic printing plate precursor for newspaper printing, comprising treating a region within 1 cm from the edge of a lithographic printing plate precursor having a possible image recording layer with a liquid containing an organic solvent and a water-soluble resin.   Infrared absorbing dye, radical polymerization initiator, radical polymerizable compound and polymer compound having polyoxyalkylene chain in the side chain are contained on the support and developed with printing ink and / or dampening water on the cylinder of the printing press. A lithographic printing plate precursor having a possible image recording layer is image-exposed with an infrared laser, and then treated within 1 cm from the edge of the lithographic printing plate precursor with a liquid containing an organic solvent and a water-soluble resin, and then a printing machine A method for making a lithographic printing plate, which is attached to a cylinder and developed with printing ink and / or fountain solution.

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