JP2005053111A - Printing method using original thermosensitive lithographic printing plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printing method which inhibits the processing fatigue of damping water to be used and spends only a few number of printing sheets required until the completion of aboard-the-machine development, in the aboard-the-machine development process of an original thermoplastic lithographic printing plate capable of recording an image by infrared scan exposure based on a digital signal. <P>SOLUTION: In this printing method using the original thermosensitive lithographic printing plate, the following processes are provided: a process to record an image on the original lithographic printing plate with a thermosensitive layer formed on a substrate; a process to supply the damping water containing at least one kind of chemical compound selected from the group consisting of a bromonitroalcohol compound, a 1,2-benzisothiazoline-3-ON compound, a p-hydroxybenzoic acid derivative, an azole compound and a heterocyclic alkylammonium salt to the plate surface and thereby remove the thermosensitive layer of a non-image part; and a process to print using the damping water and an ink. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a plate making using a heat-sensitive lithographic printing plate precursor and a printing method subsequent thereto. More specifically, printing using a heat-sensitive lithographic printing plate precursor capable of image recording by infrared scanning exposure based on a digital signal and capable of making an image-recorded plate as it is by on-press development on a printing machine. Regarding the method.

  Conventionally, the production of a lithographic printing plate has been performed by a system that exposes a printing plate precursor through a lith film, which is an intermediate material. However, with the rapid progress of digitization in the printing field in recent years, the printing plate preparation process is changing to a CTP system that directly outputs digital data input to a computer and edited to a printing plate precursor. Furthermore, with the aim of further streamlining processes, development-free lithographic printing plate precursors that can be printed as they are without being developed after exposure have been developed.

  One method of eliminating the processing step is to mount the exposed printing plate precursor on the plate cylinder of the printing press, and supply dampening water and ink while rotating the plate cylinder. There is a method called on-machine development that removes the image area. That is, after the printing plate precursor is exposed, it is mounted on a printing machine as it is, and the development process is completed in a normal printing process. A lithographic printing plate precursor suitable for on-press development has an image forming layer (heat-sensitive layer) that is soluble in dampening water or an ink solvent, and is developed on a printing press placed in a bright room. It is necessary to have a bright room handling property suitable for being performed.

  Various techniques related to on-press development have been proposed. For example, a photosensitive element provided with a photosensitive layer including a microcapsule containing at least an ethylenic saturated compound and a photopolymerization initiator on a support is attached to an offset printing machine without any processing after image exposure, and directly on the printing machine. It is proposed to remove the unexposed photosensitive layer and perform printing immediately (see, for example, Patent Document 1). In addition, a lithographic printing plate precursor is described in which a photosensitive layer in which fine particles of a hydrophobic thermoplastic polymer are dispersed in a hydrophilic binder polymer is provided on a hydrophilic support (see, for example, Patent Document 2). . In this publication, the lithographic printing plate precursor is subjected to infrared laser exposure, and the hydrophobic thermoplastic polymer fine particles in the heat-sensitive layer are coalesced by heat to form an image, and then the plate is mounted on the plate cylinder of a printing press, It describes that an unexposed part is removed by fountain solution and / or ink (on-press development). The lithographic printing plate precursor has suitability for handling a bright room because the photosensitive region is an infrared region.

In addition, good press life can be obtained by an on-press development type thermosensitive lithographic printing plate precursor having a microcapsule encapsulating a compound having a vinyloxy group, an image forming layer containing a hydrophilic resin and an acid precursor. (See, for example, Patent Document 3), and an on-press development type heat-sensitive film having an image forming layer containing a microcapsule containing a compound having an epoxy group, a hydrophilic resin, and an acid precursor It has been shown that good printing durability can be obtained by using a lithographic printing plate precursor (see, for example, Patent Document 4).
Furthermore, good printing durability is achieved by an on-press development type heat-sensitive lithographic printing plate precursor having a microcapsule enclosing a compound having a radical polymerizable group, a hydrophilic resin and a heat-sensitive radical generator. It has been proposed that the characteristics can be obtained (see, for example, Patent Document 5).

Japanese Patent No. 2938397 JP-A-9-127683 JP 2002-29162 A JP 2002-46361 A JP 2002-137562 A

  The lithographic printing plate precursor according to the above technique has improved printing durability, but has a problem of insufficient on-press developability when the fountain solution is fatigued. In other words, when printing is performed by supplying dampening water to the exposed original plate on the printing press, then supplying ink, and further supplying paper, non-image of the printing plate in dampening water by on-press development. Part of the lysate dissolves into the fountain solution, causing the fountain solution to rot. Due to such processing fatigue of the fountain solution, there has been a problem that the number of printing sheets required to complete the on-press development is increased. The object of the present invention is to solve this problem. That is, an object of the present invention is to provide a printing method that suppresses the processing fatigue of dampening water in the on-press development of a heat-sensitive lithographic printing plate precursor and requires less printing paper to complete on-press development. It is.

As a result of intensive studies to achieve the above-mentioned problems, the inventors of the present invention have developed a lithographic printing plate precursor having a heat-sensitive layer on a support and a specific dampening on the printing plate on the printing press after image recording. By supplying water, the heat-sensitive layer in the unexposed area is easily removed (on-machine development), and subsequently printing using the fountain solution and ink reduces the processing fatigue of the fountain solution. The inventors have found that a printed matter having no developability deterioration, little paper loss, and no non-image area stains can be obtained, and the present invention has been completed. Specifically, the number of printing paper sheets required for completion of on-press development can be reduced by blending a specific compound in the fountain solution from among compounds known as preservatives in the past. At the same time, it has been found that the treatment fatigue of the fountain solution can be suppressed.
Accordingly, the present invention comprises a step of recording an image on a lithographic printing plate precursor having a thermosensitive layer on a support, a bromonitroalcohol compound, a 1,2-benzisothiazolin-3-one compound, a p-hydroxybenzoic acid derivative, Supplying a fountain solution containing at least one compound selected from the group consisting of an azole-based compound and a heterocyclic alkylammonium salt to the plate surface, removing the heat-sensitive layer in the non-image area, and the fountain solution and A printing method using a heat-sensitive lithographic printing plate precursor characterized by comprising a step of printing with ink.

  In the present invention, the heat-sensitive layer of the heat-sensitive lithographic printing plate precursor preferably contains a hydrophobizing precursor, and further includes thermoplastic polymer fine particles, thermal reaction as specific examples of the hydrophobizing precursor. There are fine particles such as microcapsules enclosing a fine polymer fine particle and a compound having a thermally reactive group.

  The present invention is selected from the group consisting of a bromonitroalcohol compound, a 1,2-benzisothiazolin-3-one compound, a p-hydroxybenzoic acid derivative, an azole compound, and a heterocyclic alkylammonium salt at least on a printing press. At least one kind of compound is subjected to a development treatment using a fountain solution. Accordingly, the step of recording an image on the heat-sensitive lithographic printing plate precursor may be carried out on the same printing machine as that used for the development process, or a separate image-recorded heat-sensitive lithographic printing plate precursor may be printed on the printing machine. The development process may be performed by mounting on the top. In the present invention, the dampening water is supplied and a printing process is performed after a predetermined time has elapsed. However, the dampening water and the ink are substantially simultaneously supplied to perform the development process. You may go.

  According to the present invention, in the on-press development of a heat-sensitive lithographic printing plate precursor, it is possible to suppress processing fatigue of the fountain solution. A printing method that requires less printing paper can be provided.

Hereinafter, embodiments of the present invention will be described in detail in the order of plate making and printing method, dampening water, and heat-sensitive lithographic printing plate precursor.
[Plate making and printing method]
In the present invention, an image (latent image) is formed on the heat-sensitive lithographic printing plate precursor by heat prior to printing. Specifically, direct image-like recording using a thermal recording head, scanning exposure using an infrared laser, high illuminance flash exposure such as a xenon discharge lamp, infrared lamp exposure, or the like is used. In particular, exposure with a solid high-power infrared laser such as a semiconductor laser or a YAG laser that emits infrared light having a wavelength of 700 to 1200 nm is preferable. The lithographic printing plate precursor on which the image has been recorded is mounted on a printing machine without further processing, and dampening water and ink are supplied to the printing plate. In the aspect of supplying the fountain solution and the ink to the plate surface, the fountain solution and the ink may be supplied substantially simultaneously, or preferably the fountain solution is supplied to the plate surface and the on-press development is allowed to proceed to some extent. After that, ink is supplied. In this way, while supplying the fountain solution and the ink to the printing plate, the paper is further supplied and the normal printing operation is started. As described above, when the normal printing start operation for supplying dampening water and ink to the printing plate on the printing press and further supplying paper is performed, the heat-sensitive layer in the unexposed area is removed (on-press development), and printing proceeds. The same printing stability as that of a conventional lithographic printing plate can be obtained.
The plate making and printing method of the present invention is also mounted on a printing press after mounting a heat-sensitive lithographic printing plate precursor on the plate cylinder of a printing press, as disclosed in, for example, JP-A-9-123388. It can be carried out by employing a system in which exposure is performed with a laser, followed by on-press development and printing.

[Dampening water]
The fountain solution used in the present invention is selected from the group consisting of bromonitroalcohol compounds, 1,2-benzisothiazolin-3-one compounds, p-hydroxybenzoic acid derivatives, azole compounds, and heterocyclic alkylammonium salts. It contains at least one kind of compound.
The fountain solution used in the present invention is preferably at least one compound selected from bromonitroalcohol compounds, 1,2-benzisothiazolin-3-one compounds, p-hydroxybenzoic acid derivatives, and azole compounds. More preferably, it contains at least one compound selected from a bromonitroalcohol-based compound and a 1,2-benzisothiazolin-3-one compound.

  The bromonitroalcohol compound contained in the fountain solution used in the present invention will be described. Here, the bromonitroalcohol-based compound includes compounds represented by the following general formulas [A] to [C].

（式中、Ｒ₁〜Ｒ₁₃はそれぞれ独立に水素原子又はアルキル基を表す。）

(In the formula, R _{1 to} R ₁₃ each independently represents a hydrogen atom or an alkyl group.)

When R _{1 to} R ₁₃ in the general formulas [A] to [C] represent an alkyl group, a lower alkyl group is preferable, particularly an alkyl group having 1 to 3 carbon atoms such as a methyl group, an ethyl group, a propyl group, An isopropyl group or the like is suitable. One or more of these bromonitroalcohol compounds can be used.
Among the bromonitroalcohol compounds used in the present invention, particularly preferred are 2-bromo-2-nitropropane-1,3-diol (pronopol), 1,1-dibromo-1-nitro-2-ethanol (DBNE). ), 1,1-dibromo-1-nitro-2-propanol (DBNP), 3-bromo-3-nitropentane-2,4-diol, and the like. Many bromonitroalcohol compounds are poorly water-soluble substances, but can be used by dissolving in methanol or glycol organic solvents. Further, it can be used as a fountain solution by using an anionic, cationic or nonionic surfactant in combination without using an organic solvent.
0.001-5 mass% is suitable for content of the bromonitro alcohol type compound in dampening water, Preferably it is 0.005-3 mass%.

（式中、Ｒは水素原子又はアルキル基を表し、Ｘはアルキル基、アルコキシ基、又はハロゲン原子を表し、ｎは０又は１〜４の整数を表す。）
上記式中、Ｒがアルキル基を表すとき、低級アルキル基が好ましく、具体的に炭素原子数１〜４のアルキル基が好ましく、特にメチル基が挙げられる。Ｘがアルキル基を表すとき、低級アルキル基が好ましく、具体的に炭素原子数１〜４のアルキル基が好ましい。Ｘがアルコキシ基を表すとき、炭素原子数１〜４のアルコキシ基が好ましい。Ｘがハロゲン原子を表すとき、塩素原子、臭素原子が好ましい。 Next, the 1,2-benzisothiazolin-3-one compound will be described. Among the 1,2-benzisothiazolin-3-one compounds, one that is preferably used is 1,2-benzisothiazolin-3-one having the following structural formula.

(In the formula, R represents a hydrogen atom or an alkyl group, X represents an alkyl group, an alkoxy group, or a halogen atom, and n represents 0 or an integer of 1 to 4).
In the above formula, when R represents an alkyl group, a lower alkyl group is preferable, specifically an alkyl group having 1 to 4 carbon atoms, and particularly a methyl group. When X represents an alkyl group, a lower alkyl group is preferable, and an alkyl group having 1 to 4 carbon atoms is particularly preferable. When X represents an alkoxy group, an alkoxy group having 1 to 4 carbon atoms is preferable. When X represents a halogen atom, a chlorine atom or a bromine atom is preferable.

湿し水における１，２−ベンズイソチアゾリン−３−オン化合物の含有量は、０．００１〜５質量％が適当であり、好ましくは０．００５〜３質量％である。 In the fountain solution used in the present invention, one or more 1,2-benzisothiazolin-3-one compounds can be used.
Among the 1,2-benzisothiazolin-3-one compounds used in the present invention, the following are preferably used.

The content of the 1,2-benzisothiazolin-3-one compound in the fountain solution is suitably 0.001 to 5% by mass, preferably 0.005 to 3% by mass.

Examples of the p-hydroxybenzoic acid derivative included in the fountain solution used in the present invention include isobutyl p-hydroxybenzoate, isopropyl p-hydroxybenzoate, ethyl p-hydroxybenzoate, butyl p-hydroxybenzoate, p- Examples include propyl hydroxybenzoate, methyl p-hydroxybenzoate, vinyl p-hydroxybenzoate, and the like.
In the fountain solution used in the present invention, one or more p-hydroxybenzoic acid derivatives can be used.
0.001-5 mass% is suitable for content of the p-hydroxybenzoic acid derivative in dampening water, Preferably it is 0.005-3 mass%.

As an example of the azole compound contained in the fountain solution used in the present invention, α- (4-chlorophenyl) -α- (1-cyclopropylethyl) -1H-1,2,4-triazole-1-ethanol (generic name) Cyproconazole), (±) α- [2- (4-chlorophenyl) ethyl] -α- (1,1-dimethylethyl) -1H-1,2,4-triazole-1-ethanol (generic name: Tebuconazole), and 1-[[2- (2,4-dichlorophenyl) -4-n-propyl-1,3-dioxolan-2-yl] methyl] -1H-1,2,4-triazole (generic name: Propiconazole).
In the fountain solution used in the present invention, one or more azole compounds can be used.
0.001-5 mass% is suitable for content of the azole compound in dampening water, Preferably it is 0.005-3 mass%.

In addition, the heterocyclic alkylammonium salt included in the fountain solution used in the present invention includes one or more heterocyclic alkyls selected from the group consisting of alkyl-pyridinium salts, alkyl-quinolinium salts and alkyl-isoquinolinium salts. Ammonium salts are preferred, and among them, those having an alkyl group having 8 to 18 carbon atoms are preferred. For example, lauryl isoquinolinium chloride, cetyl pyridinium chloride and the like can be mentioned.
0.001-5 mass% is suitable for content of the heterocyclic alkyl ammonium salt in dampening water, Preferably it is 0.005-3 mass%.

  The fountain solution used in the present invention is selected from the group consisting of bromonitroalcohol compounds, 1,2-benzisothiazolin-3-one compounds, p-hydroxybenzoic acid derivatives, azole compounds, and heterocyclic alkylammonium salts. When at least two or more kinds of compounds are included, the total content thereof is suitably in the range of 0.001 to 5% by mass.

In addition, the fountain solution used in the present invention may include the following.
(a) Acetylene glycols and acetylene alcohols
(b) Auxiliary agent for improving wettability
(c) Water-soluble polymer compound
(d) pH adjuster
(e) Odor masking agent
(f) Others ((i) preservatives, (ii) chelating agents, (iii) colorants, (iv) rust inhibitors, (v) antifoaming agents, etc.)

Specific examples of acetylene glycols and acetylene alcohols contained in the fountain solution include 2,4,7,9-tetramethyl-5-decyne-4,7-diol, 3,5-dimethyl-1-hexyne-3- All, propargyl alcohol (2-propyn-1-ol), 3-butyn-1-ol, 1-butyne-3-ol, 2-butyne-1,4-diol, 3,6-dimethyl-4-octyne- 3,6-diol and the like can be mentioned. Two or more of these compounds may be used in combination.
In particular, 2,4,7,9-tetramethyl-5-decyne-4,7-diol or 3,5-dimethyl-1-hexyn-3-ol is fast on-press development and starts normal printing with a small number of sheets. Can be preferably used. 0.001-1 mass% is suitable for content of these compounds in dampening water, More preferably, it is 0.005-0.1 mass%.

  (b) A surfactant or other solvent can be used as an aid for improving wettability. Among the surfactants, for example, anionic surfactants include fatty acid salts, abietic acid salts, hydroxyalkane sulfonic acid salts, alkane sulfonic acid salts, dialkyl sulfosuccinic acid salts, linear alkyl benzene sulfonic acid salts, branched alkyl benzene sulfonic acid. Acid salts, alkylnaphthalene sulfonates, alkylphenoxy polyoxyethylenepropyl sulfonates, polyoxyethylene alkylsulfenyl ether salts, N-methyl-N-oleyl taurine sodium salts, N-alkylsulfosuccinic acid monoamide disodium salts, Petroleum sulfonates, sulfated castor oil, sulfated beef tallow oil, sulfate esters of fatty acid alkyl esters, alkyl sulfate esters, polyoxyethylene alkyl ether sulfate esters, fatty acids Noglyceride sulfates, polyoxyethylene alkylphenyl ether sulfates, polyoxyethylene styryl phenyl ether sulfates, alkyl phosphates, polyoxyethylene alkyl ether phosphates, polyoxyethylene alkylphenyl ether phosphates, styrene -Partially saponified products of maleic anhydride copolymer, partial saponified products of olefin-maleic anhydride copolymer, naphthalene sulfonate formalin condensate and the like. Among these, dialkyl sulfosuccinates, alkyl sulfates and alkyl naphthalene sulfonates are particularly preferably used.

  Nonionic surfactants include polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene polystyryl phenyl ethers, polyoxyethylene polyoxypropylene alkyl ethers, glycerin fatty acid partial esters, sorbitan Fatty acid partial esters, pentaerythritol fatty acid partial esters, propylene glycol mono fatty acid esters, sucrose fatty acid partial esters, polyoxyethylene sorbitan fatty acid partial esters, polyoxyethylene sorbitol fatty acid partial esters, polyethylene glycol fatty acid esters, poly Glycerin fatty acid partial esters, polyoxyethylenated castor oil, polyoxyethylene glycerin fatty acid partial esters, fatty acid die Examples include olamides, N, N-bis-2-hydroxyalkylamines, polyoxyethylene alkylamines, triethanolamine fatty acid esters, polyoxyethylene-polyoxypropylene block polymers, and trialkylamine oxides. . In addition, fluorine-based surfactants and silicon-based surfactants can also be used. In the case of using a surfactant, the content thereof is 1% by mass or less, preferably 0.001 to 0.5% by mass in consideration of foaming. Two or more kinds can be used in combination.

  Other auxiliaries include ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, triethylene glycol monomethyl ether, tetraethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monoethyl ether, triethylene glycol monoethyl ether, tetraethylene glycol mono Ethyl ether, ethylene glycol monopropyl ether, diethylene glycol monopropyl ether, triethylene glycol monopropyl ether, tetraethylene glycol monopropyl ether, ethylene glycol monoisopropyl ether, diethylene glycol monoisopropyl ether, triethylene glycol monoisopropyl ether, Tetra Tylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, tetraethylene glycol monobutyl ether, ethylene glycol monoisobutyl ether, diethylene glycol monoisobutyl ether, triethylene glycol monoisobutyl ether, tetraethylene glycol mono Isobutyl ether, ethylene glycol monotertiary butyl ether, diethylene glycol monotertiary butyl ether, triethylene glycol monotertiary butyl ether, tetraethylene glycol monotertiary butyl ether,

  Propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, tripropylene glycol monomethyl ether, propylene glycol monoethyl ether, dipropylene glycol monoethyl ether, tripropylene glycol monoethyl ether, tetrapropylene glycol monoethyl ether, propylene glycol monopropyl ether, Dipropylene glycol monopropyl ether, tripropylene glycol monopropyl ether, propylene glycol monoisopropyl ether, dipropylene glycol monoisopropyl ether, tripropylene glycol monoisopropyl ether, dipropylene glycol monobutyl ether, tripropylene glycol monobutyl ether, propylene Glycol monoisobutyl ether, dipropylene glycol monoisobutyl ether, tripropylene glycol monoisobutyl ether, propylene glycol monotertiary butyl ether, dipropylene glycol monotertiary butyl ether, tripropylene glycol monotertiary butyl ether, polypropylene glycol having a molecular weight of 200 to 1000 And their monomethyl ether, monoethyl ether, monopropyl ether, monoisopropyl ether and monobutyl ether,

Propylene glycol, dipropylene glycol, tripropylene glycol, tetrapropylene glycol and pentapropylene glycol, ethylene glycol, diethylene glycol, triethylene glycol, butylene glycol, hexylene glycol, 2-ethyl-1,3-hexanediol, 3-methoxy- 3-methyl-1-butanol, 1-butoxy-2-propanol, glycerin, diglycerin, polyglycerin, trimethylolpropane, 2-pyrrolidone derivatives substituted at the 1-position with an alkyl group having 1 to 8 carbon atoms, and the like Is mentioned. Among these, ethylene glycol monotertiary butyl ether, 3-methoxy-3-methyl-1-butanol, and 1-butoxy-2-propanol are preferably used.
These solvents may be used alone or in combination of two or more. In general, these solvents are suitably used in the range of 0.02 to 1% by mass, preferably 0.05 to 0.5% by mass, based on the total mass of the fountain solution.

Examples of the water-soluble polymer compound (c) used in the fountain solution of the present invention include gum arabic, starch derivatives (for example, dextrin, enzymatically degraded dextrin, hydroxypropylated enzymatically degraded dextrin, carboxymethylated starch, and phosphate starch. Octenyl succinylated starch), alginate, fibrin derivatives (for example, carboxymethyl cellulose, carboxyethyl cellulose, methyl cellulose, hydroxyethyl cellulose) and other natural products and modified products thereof, polyethylene glycol and copolymers thereof, polyvinyl alcohol and derivatives thereof, poly Combination of acrylamide and its copolymer, polyacrylic acid and its copolymer, vinyl methyl ether / maleic anhydride copolymer, vinyl acetate / maleic anhydride copolymer, polystyrene sulfonic acid and its copolymer Things, polyvinylpyrrolidone, and the like. Among these, carboxymethyl cellulose and hydroxyethyl cellulose are particularly preferable. 0.001-0.5 mass% is suitable with respect to dampening water, and, as for content of a water-soluble polymer compound, More preferably, it is 0.005-0.2 mass%.

  As the (d) pH adjusting agent used in the fountain solution of the present invention, at least one selected from water-soluble organic acids, inorganic acids and salts thereof can be used, and these compounds adjust the pH of the fountain solution. Alternatively, it is effective for pH buffering, moderate etching of the lithographic printing plate support or anticorrosion. Preferred organic acids include, for example, citric acid, ascorbic acid, malic acid, tartaric acid, lactic acid, acetic acid, gluconic acid, hydroxyacetic acid, succinic acid, malonic acid, levulinic acid, sulfanilic acid, p-toluenesulfonic acid, phytic acid, and organic phosphones. An acid etc. are mentioned. Examples of the inorganic acid include phosphoric acid, nitric acid, sulfuric acid, and polyphosphoric acid. Furthermore, alkali metal salts, alkaline earth metal salts or ammonium salts of these organic acids and / or inorganic acids, and organic amine salts are also preferably used. One of these organic acids, inorganic acids and salts thereof may be used alone, or a mixture of two or more may be used.

  The addition amount of these pH adjusting agents to the fountain solution is more preferably in the range of 0.001% by mass or more and 0.1% by mass or less in combination of the organic acid, the inorganic acid and their salts. When it is 0.001% by mass or more, the stain at the time of printing is good due to the etching force of aluminum which is the support of the lithographic printing plate. On the other hand, if it is 0.1 mass% or less, it is preferable at the point of rust of a printing press. The pH value of the fountain solution is preferably used in an acidic region in the range of 3 to 7, but pH 7 to 11 containing alkali metal hydroxide, phosphoric acid, alkali metal salt, alkali metal carbonate, silicate, etc. It can also be used in the alkaline region.

(e) Odor masking agents include esters that are conventionally known for use as perfumes. For example, there is one represented by the following general formula (I).
R ₁ -COOR ₂ (I)
In the compound of the general formula (I), R ₁ is an alkyl group having 1 to 15 carbon atoms, an alkenyl group, an aralkyl group, or a phenyl group. In the case of an alkyl group or an alkenyl group, the number of carbon atoms is preferably 4-8. When R ₁ represents an alkyl group, an alkenyl group or an aralkyl group, they may be linear or branched. An alkenyl group having one double bond is particularly suitable. Examples of the aralkyl group include a benzyl group and a phenylethyl group. One or more hydrogen atoms of the alkyl group, alkenyl group, aralkyl group, or phenyl group represented by R ₁ may be substituted with a hydroxyl group or an acetyl group. R ₂ is an alkyl group having 3 to 10 carbon atoms, an aralkyl group, or a phenyl group, which may be linear or branched. In the case of an alkyl group, the number of carbon atoms is preferably 3 to 9. Examples of the aralkyl group include a benzyl group and a phenylethyl group.

  Specific examples of (e) odor masking agents that can be used include formic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, 2-ethylbutyric acid, valeric acid, isovaleric acid, 2-methylvaleric acid, hexanoic acid (caproic acid), 4-methylpentanoic acid (isohexanoic acid), 2-hexenoic acid, 4-pentenoic acid, heptanoic acid, 2-methylheptanoic acid, octanoic acid (caprylic acid), nonanoic acid, decanoic acid (capric acid), 2-decenoic acid , Esters of lauric acid or myristic acid. In addition, there are acetoacetate esters such as benzyl phenylacetate, ethyl acetoacetate and 2-hexyl acetoacetate. Among them, preferred are n-pentyl acetate, isopentyl acetate, n-butyl butyrate, n-pentyl butyrate and isopentyl butyrate, and n-butyl butyrate, n-pentyl butyrate and isopentyl butyrate are particularly preferable. The content of these odor masking agents (d) in the fountain solution is suitably 0.001 to 0.5% by mass, more preferably 0.002 to 0.2% by mass, based on the total mass of the fountain solution. %. By using these, the work environment can be further improved. Also. Vanillin, ethyl vanillin or the like may be used in combination.

  (F) (i) Preservative used in the fountain solution used in the present invention includes phenol or a derivative thereof, formalin, imidazole derivative, sodium dehydroacetate, 4-isothiazolin-3-one derivative, benztriazole derivative, amidine or Guanidine derivatives, quaternary ammonium salts, pyridine, quinoline or guanidine derivatives, diazine or triazole derivatives, oxazole or oxazine derivatives, bromonitroalcohol-based bromonitropropanol, 1,1-dibromo-1-nitro-2- Examples include ethanol and 3-bromo-3-nitropentane-2,4-diol. A preferable addition amount is an amount that exerts a stable effect on bacteria, molds, yeasts, etc., and varies depending on the types of bacteria, molds, yeasts, etc. The range of mass% is preferable, and it is preferable to use two or more preservatives that are effective against various molds, bacteria and yeasts.

  The fountain solution used in the present invention may further contain (f) (ii) a chelating agent. The fountain solution is usually prepared by adding tap water, well water, etc. to the fountain solution concentrated composition and diluting it at the time of use. At this time, calcium ions contained in the tap water or well water to be diluted are prepared. It may have an adverse effect on printing and may cause the printed material to become dirty easily. In such a case, the above disadvantages can be eliminated by adding a chelating agent. Preferred chelating agents include, for example, ethylenediaminetetraacetic acid, its potassium salt, its sodium salt; diethylenetriaminepentaacetic acid, its potassium salt, sodium salt; triethylenetetraminehexaacetic acid, its potassium salt, its sodium salt, hydroxyethylethylenediaminetriacetic acid Nitrilotriacetic acid, sodium salt; 1-hydroxyethane-1,1-diphosphonic acid, potassium salt, sodium salt; aminotri (methylenephosphonic acid), potassium salt, sodium salt And organic phosphonic acids and phosphonoalkanetricarboxylic acids. Instead of the sodium salt or potassium salt of the chelating agent, an organic amine salt is also effective. These chelating agents are selected so that they are stably present in the dampening water during use and do not impair the printability. As content of the chelate compound in dampening water at the time of use, 0.0001-0.5 mass% is suitable, Preferably it is 0.0005-0.2 mass%.

  As the colorant (f) (iii) used in the fountain solution used in the present invention, food colorants and the like can be preferably used. For example, CI No. 19140, 15985 as a yellow dye, CI No. 16185, 45430, 16255, 45380, 45100 as a red dye, CI No. 42640 as a purple dye, CI No. 42090, 73015 as a blue dye, CI No. 42095, and the like. Examples of the (f) (iv) rust inhibitor used in the fountain solution used in the present invention include benzotriazole, 5-methylbenzotriazole, thiosalicylic acid, benzimidazole and derivatives thereof. As the antifoaming agent (f) (v) used in the fountain solution used in the present invention, a silicon antifoaming agent is preferable, and any of an emulsified dispersion type and a solubilizing type can be used.

[Heat-sensitive lithographic printing plate precursor]
The heat-sensitive lithographic printing plate precursor used in the present invention has a heat-sensitive layer provided on a support, and more specifically has a heat-sensitive layer on a hydrophilic support, and the heat-sensitive layer is preferably Contains a hydrophobizing precursor.
The hydrophobizing precursor used in the heat-sensitive layer is preferably fine particles that can convert the hydrophilic heat-sensitive layer to hydrophobic when heat is applied, for example, thermoplastic polymer fine particles, heat-reactive polymer Examples include microcapsules enclosing fine particles and a hydrophobic compound. The heat-sensitive layer can contain at least one kind of fine particles selected from thermoplastic polymer fine particles, heat-reactive polymer fine particles, and microcapsules enclosing a hydrophobic compound.

As thermoplastic polymer fine particles used in the heat-sensitive layer, Research Disclosure No. 33303 of January 1992, JP-A-9-123387, JP-A-9-131850, JP-A-9-171249, JP-A-9-171250. The thermoplastic polymer fine particles described in the gazette and European Patent Application No. 931647 can be mentioned as suitable examples. Specific examples of the polymer constituting the polymer fine particle include homopolymers of monomers such as ethylene, styrene, vinyl chloride, methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, vinylidene chloride, acrylonitrile, vinyl carbazole, or the like. Mention may be made of copolymers or mixtures thereof. Among them, more preferred are polystyrene and polymethyl methacrylate.
The average particle size of the thermoplastic polymer fine particles used in the present invention is preferably 0.01 to 2.0 μm. As a method for synthesizing such thermoplastic polymer fine particles, in addition to emulsion polymerization and suspension polymerization, these compounds are dissolved in a water-insoluble organic solvent, and this is mixed and emulsified with an aqueous solution containing a dispersant. Further, there is a method (solution dispersion method) in which heat is further applied to solidify into fine particles while the organic solvent is being blown away.

Examples of the heat-reactive polymer fine particles used in the present invention include thermosetting polymer fine particles and polymer fine particles having a heat-reactive group.
Examples of the thermosetting polymer include a resin having a phenol skeleton, a urea resin (for example, a urea derivative such as urea or methoxymethylated urea resinized with an aldehyde such as formaldehyde), a melamine resin (for example, melamine). Or a derivative thereof obtained by resinification with aldehydes such as formaldehyde), alkyd resins, unsaturated polyester resins, polyurethane resins, epoxy resins, and the like. Among these, resins having a phenol skeleton, melamine resins, urea resins and epoxy resins are particularly preferable. Suitable resins having a phenol skeleton include, for example, phenol resins obtained by converting phenol, cresol and the like with aldehydes such as formaldehyde, hydroxystyrene resins, N- (p-hydroxyphenyl) methacrylamide, and p-hydroxyphenyl methacrylate. Examples thereof include a polymer or copolymer of methacrylamide or acrylamide or methacrylate or acrylate having a phenol skeleton.
The average particle diameter of the thermosetting polymer fine particles used in the present invention is preferably 0.01 to 2.0 μm. Such thermosetting polymer fine particles can be easily obtained by a solution dispersion method, but may be formed into fine particles when the thermosetting polymer is synthesized. However, it is not restricted to these methods.

  The thermal reactive group of the polymer fine particle having a thermal reactive group used in the present invention may be any functional group capable of performing a reaction as long as a chemical bond is formed. Saturated group (for example, acryloyl group, methacryloyl group, vinyl group, allyl group, etc.), cationically polymerizable group (for example, vinyl group, vinyloxy group, etc.), isocyanate group that performs addition reaction or its block, epoxy group, vinyloxy Groups and functional groups having active hydrogen atoms that are reaction partners (for example, amino groups, hydroxyl groups, carboxyl groups, etc.), carboxyl groups that perform condensation reactions, and hydroxyl groups or amino groups that are reaction partners, ring-opening addition reactions Suitable examples include acid anhydrides and amino or hydroxyl groups that are reaction partners. Can. The introduction of these functional groups into the polymer fine particles may be performed at the time of polymerization, or may be performed using a polymer reaction after the polymerization. When introduced at the time of polymerization, it is preferable to carry out emulsion polymerization or suspension polymerization of the monomer having the above functional group. Specific examples of the monomer having the above functional group include allyl methacrylate, allyl acrylate, vinyl methacrylate, vinyl acrylate, 2- (vinyloxy) ethyl methacrylate, p-vinyloxystyrene, p- {2- (vinyloxy) ethyl} styrene, Block isocyanate with glycidyl methacrylate, glycidyl acrylate, 2-isocyanatoethyl methacrylate or alcohol thereof, block isocyanate with 2-isocyanate ethyl acrylate or alcohol thereof, 2-aminoethyl methacrylate, 2-aminoethyl acrylate, 2- Hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, acrylic acid, methacrylic acid, maleic anhydride, bifunctional acrylate, 2 officers Methacrylate, and the like, but not limited thereto.

  In the present invention, a copolymer of these monomers and a monomer that is copolymerizable with these monomers and does not have a thermally reactive group can also be used. Examples of the copolymer monomer having no heat-reactive group include styrene, alkyl acrylate, alkyl methacrylate, acrylonitrile, vinyl acetate, and the like. It is not limited to. Examples of the polymer reaction used when the introduction of the thermally reactive group is carried out after the polymerization include the polymer reaction described in International Publication No. 96/34316 pamphlet.

  Among the polymer fine particles having a heat-reactive group, those in which the polymer fine particles are coalesced by heat are preferable, and those having a hydrophilic surface and being dispersed in water are particularly preferable. The contact angle (water droplets) of the film prepared by applying only polymer fine particles and drying at a temperature lower than the solidification temperature is higher than the contact angle (water droplets) of the film prepared by drying at a temperature higher than the solidification temperature. It is preferable to lower. In order to make the surface of the polymer fine particles hydrophilic in this way, a hydrophilic polymer or oligomer such as polyvinyl alcohol or polyethylene glycol or a hydrophilic low molecular weight compound may be adsorbed on the surface of the polymer fine particles. However, the surface hydrophilization method is not limited to this.

  The solidification temperature of the polymer fine particles having these thermoreactive groups is preferably 70 ° C. or higher, but more preferably 100 ° C. or higher in view of the stability over time. The average particle size of the polymer fine particles is preferably 0.01 to 2.0 μm, more preferably 0.05 to 2.0 μm, and most preferably 0.1 to 1.0 μm. Within this range, good resolution and stability over time can be obtained.

  The microcapsule used in the present invention contains a hydrophobizing compound. As the hydrophobic compound, a compound having a thermally reactive functional group is preferable. As this heat-reactive group, the same heat-reactive group as that used for the polymer fine particles having the heat-reactive group can be mentioned as a preferable one. Hereinafter, the compound having a thermally reactive group will be described in more detail.

  Preferred examples of the compound having a radically polymerizable unsaturated group include a compound having at least one, preferably two or more, ethylenically unsaturated bonds such as acryloyl group, methacryloyl group, vinyl group and allyl group. . Such a group of compounds is widely known as a monomer or a crosslinking agent for the polymerizable composition in the industrial field, and these can be used in the present invention without any particular limitation. The chemical form is a monomer, a prepolymer, that is, a dimer, a trimer, an oligomer, a polymer or a copolymer, or a mixture thereof.

  Specific examples include compounds described in JP-A-2001-277740 as compounds having a polymerizable unsaturated group. Typical compound examples include trimethylolpropane di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol di (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, di Examples include pentaerythritol di (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and adducts of trimethylolpropane diacrylate and xylylene diisocyanate. However, it is not limited to these.

  An example of a polymer or copolymer having an ethylenically polymerizable unsaturated group is a copolymer of allyl methacrylate. For example, allyl methacrylate / methacrylic acid copolymer, allyl methacrylate / ethyl methacrylate copolymer, allyl methacrylate / butyl methacrylate copolymer and the like can be mentioned.

  Examples of the compound having a vinyloxy group suitable for the present invention include compounds described in JP-A-2002-29162. Specific examples include tetramethylene glycol divinyl ether, trimethylolpropane trivinyl ether, tetraethylene glycol divinyl ether, pentaerythritol divinyl ether, pentaerythritol trivinyl ether, pentaerythritol tetravinyl ether, 1,4-bis {2- (vinyloxy) ethyloxy} Benzene, 1,2-bis {2- (vinyloxy) ethyloxy} benzene, 1,3-bis {2- (vinyloxy) ethyloxy} benzene, 1,3,5-tris {2- (vinyloxy) ethyloxy} benzene, 4 , 4'-bis {2- (vinyloxy) ethyloxy} biphenyl, 4,4'-bis {2- (vinyloxy) ethyloxy} diphenyl ether, 4,4'-bis {2- (vinyloxy) Tiloxy} diphenylmethane, 1,4-bis {2- (vinyloxy) ethyloxy} naphthalene, 2,5-bis {2- (vinyloxy) ethyloxy} furan, 2,5-bis {2- (vinyloxy) ethyloxy} thiophene, , 5-bis {2- (vinyloxy) ethyloxy} imidazole, 2,2-bis [4- {2- (vinyloxy) ethyloxy} phenyl] propane {bis (vinyloxyethyl) ether of bisphenol A}, 2,2- Examples include, but are not limited to, bis {4- (vinyloxymethyloxy) phenyl} propane, 2,2-bis {4- (vinyloxy) phenyl} propane, and the like.

  As the compound having an epoxy group suitable for the present invention, a compound having two or more epoxy groups is preferable, and a glycidyl ether compound obtained by reaction of a polyhydric alcohol or a polyhydric phenol with epichlorohydrin or a prepolymer thereof. Furthermore, a polymer or copolymer of glycidyl acrylate or glycidyl methacrylate can be used.

  Specific examples include propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, trimethylolpropane triglycidyl ether, diglycidyl ether of hydrogenated bisphenol A, hydroquinone diglycidyl. Ether, resorcinol diglycidyl ether, diglycidyl ether or epichlorohydrin polyadduct of bisphenol A, diglycidyl ether or epichlorohydrin polyadduct of bisphenol F, diglycidyl ether or epichlorohydride of halogenated bisphenol A Phosphorus polyadduct, diglycidyl ether of biphenyl type bisphenol or epichlorohydrin polyadduct, novolak tree Etc. glycidyl ethers, furthermore, methyl methacrylate / glycidyl methacrylate copolymer, methacrylic acid ethyl / glycidyl methacrylate copolymer, and the like.

  Commercially available products of the above compounds include, for example, Epicoat 1001 (molecular weight: about 900, epoxy equivalent: 450 to 500), Epicoat 1002 (molecular weight: about 1600, epoxy equivalent: 600 to 700), Epicoat 1004 (about) manufactured by Japan Epoxy Resin Co., Ltd. 1060, epoxy equivalent 875-975), Epicoat 1007 (molecular weight about 2900, epoxy equivalent 2000), Epicoat 1009 (molecular weight about 3750, epoxy equivalent 3000), Epicoat 1010 (molecular weight about 5500, epoxy equivalent 4000), Epicoat 1100L (epoxy equivalent) 4000), Epikote YX31575 (epoxy equivalent 1200), Sumitomo Chemical Co., Ltd. Sumiepoxy ESCN-195XHN, ESCN-195XL, ESCN-195XF, and the like.

  Suitable isocyanate compounds for the present invention include tolylene diisocyanate, diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate, xylylene diisocyanate, naphthalene diisocyanate, cyclohexanephenylene diisocyanate, isophorone diisocyanate, Examples include hexamethylene diisocyanate, cyclohexyl diisocyanate, and compounds obtained by blocking these with alcohol or amine.

  Suitable amine compounds for the present invention include ethylenediamine, diethylenetriamine, triethylenetetramine, hexamethylenediamine, propylenediamine, polyethyleneimine and the like.

  Examples of the compound having a hydroxyl group suitable for the present invention include a compound having a terminal methylol group, a polyhydric alcohol such as pentaerythritol, and bisphenol / polyphenols.

  Examples of the compound having a carboxyl group suitable for the present invention include aromatic polyvalent carboxylic acids such as pyromellitic acid, trimellitic acid and phthalic acid, and aliphatic polyvalent carboxylic acids such as adipic acid.

  Suitable acid anhydrides for the present invention include pyromellitic acid anhydride and benzophenone tetracarboxylic acid anhydride.

  As a method for microencapsulating the above compound having a thermoreactive group, a known method can be applied. For example, as a method for producing microcapsules, a method using coacervation as described in US Pat. Nos. 2,800,047 and 2,800,498, British Patent No. 990443, US Pat. No. 3,287,154, Japanese Patent Publication 38-19574, 42-446, 42-711, a method by an interfacial polymerization method, US Pat. Nos. 3,418,250, 3660304, a method by polymer precipitation, US Pat. No. 3,796,669, a method using an isocyanate polyol wall material, US Pat. No. 3,914,511, a method using an isocyanate wall material, US Pat. Nos. 4,001,140, 4,087,376 and 4,089,802. Urea-formaldehyde system or A method using a urea formaldehyde-resorcinol wall forming material, a method using a wall material such as melamine-formaldehyde resin, hydroxycellulose, etc. found in US Pat. No. 4,025,445, Japanese Patent Publication Nos. 36-9163 and 51-9079 In-situ method by monomer polymerization, as described in British Patent No. 930422, US Pat. No. 3,111,407, Spray drying method, British Patent Nos. 952807 and 967074 There are laws, but it is not limited to these.

  A preferable microcapsule wall used in the present invention has a three-dimensional cross-linking and has a property of swelling with a solvent. From such a viewpoint, the wall material of the microcapsule is preferably polyurea, polyurethane, polyester, polycarbonate, polyamide, and a mixture thereof, and particularly preferably polyurea and polyurethane. A compound having a thermally reactive group may be introduced into the microcapsule wall.

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

  Such microcapsules may be combined with each other by heat or may not be combined. In short, among the microcapsule inclusions, the one that oozes out of the capsule surface or outside the microcapsule at the time of application, or the one that enters the microcapsule wall may cause a chemical reaction by heat. You may react with the added hydrophilic resin or the added low molecular weight compound. Alternatively, two or more types of microcapsules may be reacted with each other by providing functional groups that can thermally react with different functional groups. Therefore, it is preferable for image formation that the microcapsules are fused and united by heat, but it is not essential.

  The amount of the polymer fine particles and microcapsules added to the heat-sensitive layer is preferably 50% by mass or more, and more preferably 70 to 98% by mass in terms of solid content in any fine particle. Within this range, a good image can be formed and good printing durability can be obtained.

  When the microcapsules are contained in the heat-sensitive layer, a solvent that dissolves the inclusions and swells the wall material can be added to the microcapsule dispersion medium. By such a solvent, diffusion of the encapsulated compound having a thermally reactive group to the outside of the microcapsule is promoted. Such a solvent depends on the microcapsule dispersion medium, the material of the microcapsule wall, the wall thickness, and the inclusion, but can be easily selected from many commercially available solvents. For example, in the case of a water-dispersible microcapsule comprising a crosslinked polyurea or polyurethane wall, alcohols, ethers, acetals, esters, ketones, polyhydric alcohols, amides, amines, fatty acids and the like are preferable.

  Specific compounds include methanol, ethanol, tertiary butanol, n-propanol, tetrahydrofuran, methyl lactate, ethyl lactate, methyl ethyl ketone, propylene glycol monomethyl ether, ethylene glycol diethyl ether, ethylene glycol monomethyl ether, γ-butyl lactone, N, There are N-dimethylformamide, N, N-dimethylacetamide, and the like, but not limited thereto. Two or more of these solvents may be used. A solvent that does not dissolve in the microcapsule dispersion but dissolves when the solvent is mixed can also be used.

  The amount of the solvent added is determined by the combination of materials, but usually 5 to 95% by mass of the coating solution is effective, and a preferable range is 10 to 90% by mass, and a more preferable range is 15 to 85%. % By mass.

  The heat-sensitive layer can contain a hydrophilic resin in order to improve the on-press developability and the film strength of the heat-sensitive layer itself. As hydrophilic resin, what has hydrophilic groups, such as a hydroxyl group, an amino group, a carboxyl group, a phosphoric acid group, a sulfonic acid group, an amide group, is preferable, for example. In addition, the hydrophilic resin reacts with the heat-reactive group of the lipophilic compound included in the microcapsule and crosslinks to increase the image strength and increase the printing durability. Therefore, the hydrophilic resin is a group that reacts with the heat-reactive group. It is preferable to have. For example, when the lipophilic compound has a vinyloxy group or an epoxy group, the hydrophilic resin preferably has a hydroxyl group, a carboxyl group, a phosphoric acid group, a sulfonic acid group, or the like. Among these, a hydrophilic resin having a hydroxyl group or a carboxyl group is preferable.

  Specific examples of hydrophilic resins include gum arabic, casein, gelatin, starch derivatives, soya gum, hydroxypropylcellulose, methylcellulose, carboxymethylcellulose and its sodium salt, cellulose acetate, sodium alginate, vinyl acetate-maleic acid copolymers, styrene-malein Acid copolymers, polyacrylic acids and their salts, polymethacrylic acids and their salts, homopolymers and copolymers of hydroxyethyl methacrylate, homopolymers and copolymers of hydroxyethyl acrylate, homopolymers and copolymers of hydroxypropyl methacrylate, hydroxypropyl acrylate Homopolymers and copolymers, hydroxybutyl methacrylate homopolymers and copolymers, Homopolymers and copolymers of butyl acrylate, polyethylene glycols, hydroxypropylene polymers, polyvinyl alcohols, hydrolyzed polyvinyl acetate having a degree of hydrolysis of at least 60% by weight, preferably at least 80% by weight, polyvinyl formal, polyvinyl pyrrolidone, acrylamide Homopolymers and copolymers, methacrylamide homopolymers and copolymers, homopolymers and copolymers of N-methylolacrylamide, homopolymers and copolymers of 2-acrylamido-2-methyl-1-propanesulfonic acid, 2-methacryloyloxyethylphosphonic acid Examples include homopolymers and copolymers.

  The amount of the hydrophilic resin added to the heat-sensitive layer is preferably 20% by mass or less, and more preferably 10% by mass or less.

  Further, the hydrophilic resin may be used after being cross-linked to such an extent that an unexposed portion can be developed on-press on a printing press. Crosslinking agents include glyoxal, aldehydes such as melamine formaldehyde resin, urea formaldehyde resin, methylol compounds such as N-methylol urea, N-methylol melamine, and methylolated polyamide resin, divinyl sulfone and bis (β-hydroxyethylsulfonic acid) Active vinyl compounds such as, epoxy compounds such as epichlorohydrin and polyethylene glycol diglycidyl ether, polyamides, polyamines, epichlorohydrin adducts, polyamide epichlorohydrin resins, ester compounds such as monochloroacetic acid esters and thioglycolic acid esters, Polycarboxylic acids such as polyacrylic acid and methyl vinyl ether / maleic acid copolymer, inorganic such as boric acid, titanyl sulfate, Cu, Al, Sn, V, Cr salts Crosslinking agents, such as modified polyamide polyimide resin. In addition, a crosslinking catalyst such as ammonium chloride, a silane coupling agent, a titanate coupling agent, or the like can be used in combination.

  The heat-sensitive layer contains a light-to-heat conversion agent having a function of heating light to increase sensitivity. As a photothermal conversion agent, what is necessary is just a substance which absorbs infrared rays, especially near infrared rays (wavelength 700-2000 nm), and various well-known pigments, dyes or pigment | dyes, and metal microparticles | fine-particles can be used.

  For example, the pigments described in JP-A-2001-301350, JP-A-2002-137562, Journal of the Japan Printing Society, 38-35-40 (2001) “New Imaging Materials, 2. Near-Infrared Absorbing Dye”, etc., Dyes or pigments and metal fine particles are preferably used. As the pigment and the metal fine particles, those subjected to a known surface treatment can be used as necessary.

  More specifically, as dyes or pigments, U.S. Pat. Nos. 4,756,993 and 4,973,572, JP-A-10-268512, JP-A-11-235883, JP-B-5-13514, and JP-A-5-19702 are disclosed. And cyanine dyes, polymethine dyes, azomethine dyes, squarylium dyes, pyrylium and thiopyrylium salt dyes, dithiol metal complexes, and phthalocyanine dyes described in JP-A No. 2001-347765. Particularly preferred are cyanine dyes, squarylium dyes, pyrylium salts, and phthalocyanine dyes.

  Examples of the pigment include insoluble azo pigments, azo lake pigments, condensed azo pigments, chelate azo pigments, phthalocyanine pigments, anthraquinone pigments, perylene and perinone pigments, thioindigo pigments, quinacridone pigments, dioxazine pigments, isoindolinone pigments, Kinophthalone pigments, dyed lake pigments, azine pigments, nitroso pigments, nitro pigments, natural pigments, fluorescent pigments, inorganic pigments, carbon black, and the like can be used. Of these, carbon black is preferred.

  As the metal fine particles, fine particles of Ag, Au, Cu, Sb, Ge and Pb are preferable, and fine particles of Ag, Au and Cu are more preferable.

When the photothermal conversion agent is added to the heat-sensitive layer, it may be added in a form contained in polymer fine particles or microcapsules, or may be added in a hydrophilic medium outside these fine particles. Specific examples of particularly suitable photothermal conversion agents are shown below, but are not limited thereto. (IR-1) to (IR-11) are hydrophilic photothermal conversion agents suitable for addition in a hydrophilic medium, and (IR-21) to (IR-29) are polymer fine particles or microparticles. A lipophilic photothermal conversion agent suitable for inclusion in capsules.

  The addition ratio of the photothermal conversion agent is preferably 1 to 50 mass%, more preferably 3 to 25 mass%, based on the solid content of the heat sensitive layer. Within these ranges, good sensitivity can be obtained without impairing the film strength of the heat sensitive layer.

  The thermosensitive layer can also contain a reaction accelerator that initiates or accelerates the reaction of the thermally reactive groups. Further, since the reaction accelerator generates an acid or a radical, it can form a print-out system in combination with a dye that changes color with the generated acid or radical. Suitable examples of the reaction accelerator include known acid precursors, acid generators, and compounds called thermal radical generators. For example, a photoinitiator for photocationic polymerization, a photoinitiator for radical photopolymerization, an acid generator for printout image formation, an acid generator used for microresist, and the like.

More specifically, organohalogen compounds represented by trihalomethyl-substituted heterocyclic compounds described in JP-A-2002-29162, JP-A-2002-46361, JP-A-2002-137562, etc. Examples thereof include a compound capable of generating a sulfonic acid by photolysis represented by phonate, a disulfone compound, and an onium salt (for example, an iodonium salt, a diazonium salt, a sulfonium salt, and the like). Moreover, the compound which introduce | transduced the group or compound which generate | occur | produces these acids or radicals into the principal chain or side chain of a polymer can also be used. Although the example of a compound is given to the following, it is not limited to these.

  Two or more kinds of the reaction accelerators can be used in combination. The reaction accelerator may be added directly to the heat-sensitive layer, or may be added directly to the heat-sensitive layer coating solution, or added in the form of polymer fine particles or microcapsules. The content of the reaction accelerator in the heat-sensitive layer is preferably 0.01 to 20% by mass, more preferably 0.1 to 10% by mass, based on the total solid content of the heat-sensitive layer. Within this range, good reaction initiation or acceleration effect can be obtained without impairing on-press developability.

  To the heat-sensitive layer, a compound that is discolored by an acid or a radical can be added in order to generate a printout image. As such a compound, various dyes such as diphenylmethane, triphenylmethane, thiazine, oxazine, xanthene, anthraquinone, iminoquinone, azo, and azomethine are effectively used.

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

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

  A suitable addition amount of the dye that changes color by acid or radical is 0.01 to 10% by mass with respect to the solid content of the heat-sensitive layer.

  In addition to the above, various compounds may be added to the thermosensitive layer as necessary. For example, a polyfunctional monomer can be added to the thermal layer matrix in order to further improve the printing durability. As this polyfunctional monomer, those exemplified as the monomer put in the microcapsule can be used. Among them, preferable monomers include trimethylolpropane triacrylate, pentaerythritol triacrylate, and the like.

  In the present invention, it is desirable to add a small amount of a thermal polymerization inhibitor in order to prevent unnecessary thermal polymerization of the ethylenically unsaturated compound during preparation or storage of the heat sensitive layer coating solution. Suitable thermal polymerization inhibitors include hydroquinone, p-methoxyphenol, di-t-butyl-p-cresol, pyrogallol, t-butylcatechol, benzoquinone, 4,4'-thiobis (3-methyl-6-t-butylphenol ), 2,2'-methylenebis (4-methyl-6-t-butylphenol), N-nitroso-N-phenylhydroxylamine aluminum salt and the like. The addition amount of the thermal polymerization inhibitor is preferably 0.01 to 5% by mass with respect to the weight of the total composition.

  If necessary, higher fatty acids such as behenic acid and behenic acid amide or derivatives thereof are added to prevent polymerization inhibition by oxygen, and are unevenly distributed on the surface of the heat-sensitive layer in the drying process after coating. Also good. The amount of the higher fatty acid or derivative thereof added is preferably 0.1 to about 10% by mass of the heat-sensitive layer solid content.

  In addition, inorganic fine particles may be added to the heat-sensitive layer. Examples of the inorganic fine particles include silica, alumina, magnesium oxide, titanium oxide, magnesium carbonate, calcium alginate, and a mixture thereof. Even if it is not photothermal convertible, it can be used for strengthening the film or strengthening the interfacial adhesion by surface roughening.

  The average particle size of the inorganic fine particles is preferably 5 nm to 10 μm, more preferably 10 nm to 1 μm. Within this range, the resin fine particles and the photothermal conversion agent metal fine particles are both stably dispersed in the hydrophilic resin, the film strength of the heat-sensitive layer is sufficiently maintained, and the non-hydrophilic material with excellent hydrophilicity that does not easily cause printing stains. An image portion can be formed.

  Such inorganic fine particles can be easily obtained as a commercial product such as a colloidal silica dispersion. The content of the inorganic fine particles in the heat-sensitive layer is preferably 20% by mass or less, more preferably 10% by mass or less, based on the total solid content of the heat-sensitive layer.

  In addition, for the heat-sensitive layer, in order to improve the dispersion stability of the heat-sensitive layer, the plate making and printing performance, and the coating property, JP-A-2-195356, JP-A-59-121044, JP-A-4-13149 and Nonionic, anionic, cationic, amphoteric or fluorine-based surfactants described in JP-A-2002-365789 can be added. A suitable addition amount of these surfactants is 0.005 to 1% by mass of the heat-sensitive layer total solid.

  Furthermore, a plasticizer can be added to the heat-sensitive layer, if necessary, in order to impart flexibility of the coating film. For example, polyethylene glycol, tributyl citrate, diethyl phthalate, dibutyl phthalate, dihexyl phthalate, dioctyl phthalate, tricresyl phosphate, tributyl phosphate, trioctyl phosphate, tetrahydrofurfuryl oleate and the like are used.

  The heat-sensitive layer is applied by preparing a coating solution by dissolving the necessary components described above in a solvent. Solvents used here include ethylene dichloride, cyclohexanone, methyl ethyl ketone, methanol, ethanol, propanol, ethylene glycol monomethyl ether, 1-methoxy-2-propanol, 2-methoxyethyl acetate, 1-methoxy-2-propyl acetate, dimethoxy Examples include ethane, methyl lactate, ethyl lactate, N, N-dimethylacetamide, N, N-dimethylformamide, tetramethylurea, N-methylpyrrolidone, dimethyl sulfoxide, sulfolane, γ-butyllactone, toluene, water, and the like. However, the present invention is not limited to this. These solvents are used alone or in combination. The solid content concentration of the coating solution is preferably 1 to 50% by mass.

Moreover, although the heat-sensitive layer coating amount (solid content) on the support obtained after coating and drying varies depending on the application, it is generally preferably 0.5 to 5.0 g / m ² . When the coating amount is less than this range, the apparent sensitivity increases, but the film characteristics of the heat-sensitive layer that performs the function of image recording deteriorate. Various methods can be used as a coating method. Examples thereof include bar coater coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating, and roll coating.

  The lithographic printing plate precursor used in the present invention protects the hydrophilic thermosensitive layer surface from contamination with lipophilic substances during storage and fingerprint trace contamination due to finger contact during handling. An overcoat layer containing a water-soluble resin described in JP-A-2001-162961 and JP-A-2002-19318 can be provided.

  Specific examples of water-soluble resins used in the overcoat layer include natural gums such as gum arabic, water-soluble soybean polysaccharide, fiber derivatives (eg, carboxymethyl cellulose, carboxyethyl cellulose, methyl cellulose, etc.), modified products thereof, For synthetic polymers such as white dextrin, pullulan, and enzymatically degraded etherified dextrin, polyvinyl alcohol (polyvinyl acetate having a hydrolysis rate of 65% or more), polyacrylic acid, its alkali metal salt or amine salt, and polyacrylic acid Polymer, alkali metal salt or amine salt thereof, polymethacrylic acid, alkali metal salt or amine salt thereof, vinyl alcohol / acrylic acid copolymer and alkali metal salt or amine salt thereof, polyacrylamide, copolymer thereof, polyhydroxy Ethyl acrylate, Polyvinyl Lupyrrolidone, its copolymer, polyvinyl methyl ether, vinyl methyl ether / maleic anhydride copolymer, poly-2-acrylamido-2-methyl-1-propanesulfonic acid, its alkali metal salt or amine salt, poly-2 -Acrylamido-2-methyl-1-propanesulfonic acid copolymer, its alkali metal salt or amine salt. Depending on the purpose, two or more of these resins may be mixed and used. However, the present invention is not limited to these examples.

  The overcoat layer may contain a photothermal conversion agent in order to improve sensitivity. A preferable photothermal conversion agent includes a water-soluble infrared absorbing dye. For example, (IR-1) to (IR-11) shown in the description of the thermosensitive layer are preferably used.

  In addition, a nonionic surfactant can be mainly added to the overcoat layer in the case of aqueous solution coating for the purpose of ensuring the uniformity of coating. Specific examples of such nonionic surfactants include sorbitan tristearate, sorbitan monopalmitate, sorbitan trioleate, stearic acid monoglyceride, polyoxyethylene nonylphenyl ether, polyoxyethylene dodecyl ether and the like. . The proportion of the nonionic surfactant in the overcoat layer in the total solid is preferably 0.05 to 5 mass%, more preferably 1 to 3 mass%.

  Furthermore, the overcoat layer can contain a compound having any one of fluorine atoms and silicon atoms described in JP-A-2001-341448 in order to prevent sticking between plates during stacking and storage.

  The thickness of the overcoat layer is preferably 0.1 to 4.0 μm, and more preferably 0.1 to 1.0 μm. Within this range, it is possible to prevent contamination of the heat-sensitive layer with an oleophilic substance without impairing the removability of the overcoat layer on the printing press.

  In the lithographic printing plate precursor used in the present invention, the support on which the heat-sensitive layer can be applied is a dimensionally stable plate-like material such as paper, plastic (for example, polyethylene, polypropylene, polystyrene, etc.). Laminated paper, metal plate (eg, aluminum, zinc, copper, etc.), plastic film (eg, cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate, polyethylene , Polystyrene, polypropylene, polycarbonate, polyvinyl acetal, etc.), paper or plastic film on which a metal as described above is laminated or vapor-deposited. A preferable support includes a polyester film or an aluminum plate.

  The aluminum plate is a pure aluminum plate and an alloy plate containing aluminum as a main component and containing a trace amount of different elements. Further, a plastic is laminated on a thin film of aluminum or an aluminum alloy. Examples of foreign elements contained in the aluminum alloy include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel, and titanium. The content of foreign elements in the alloy is at most 10% by mass. Further, it may be an aluminum plate from an aluminum ingot using a DC casting method or an aluminum plate from an ingot by a continuous casting method. However, as the aluminum plate applied to the present invention, conventionally known and publicly available aluminum plates can be used as appropriate.

  The thickness of the substrate used in the present invention is 0.05 mm to 0.6 mm, preferably 0.1 mm to 0.4 mm, and particularly preferably 0.15 mm to 0.3 mm.

  Prior to using the aluminum plate, it is preferable to perform a surface treatment such as roughening the surface or anodizing. By surface treatment, it becomes easy to improve hydrophilicity and secure adhesion to the heat-sensitive layer.

  The surface of the aluminum plate is roughened by various methods. For example, a method of mechanically roughening, a method of electrochemically dissolving and roughening the surface, and a method of selectively dissolving the surface chemically. By the method. As the mechanical method, a known method such as a ball polishing method, a brush polishing method, a blast polishing method, or a buff polishing method can be used. As a chemical method, a method of immersing in a saturated aqueous solution of an aluminum salt of a mineral acid as described in JP-A No. 54-31187 is suitable. In addition, as an electrochemical surface roughening method, there is a method of performing alternating current or direct current in an electrolytic solution containing an acid such as hydrochloric acid or nitric acid. Further, as disclosed in JP-A-54-63902, an electrolytic surface roughening method using a mixed acid can also be used. The roughening by the method as described above is preferably performed in such a range that the center line average roughness (Ra) of the surface of the aluminum plate is 0.2 to 1.0 μm.

  The roughened aluminum plate is subjected to alkali etching treatment using an aqueous solution of potassium hydroxide or sodium hydroxide as necessary, and further neutralized, and then anodized to increase wear resistance as desired. Processing is performed.

As the electrolyte used for the anodizing treatment of the aluminum plate, various electrolytes that form a porous oxide film can be used. In general, sulfuric acid, hydrochloric acid, oxalic acid, chromic acid, or a mixed acid thereof is used. The concentration of these electrolytes is appropriately determined depending on the type of electrolyte. The treatment conditions for anodization vary depending on the electrolyte used, and thus cannot be specified in general. However, in general, the electrolyte concentration is 1 to 80% by mass solution, the liquid temperature is 5 to 70 ° C., and the current density is 5 to 60 A / day. dm ² , voltage 1 to 100 V, and electrolysis time 10 seconds to 5 minutes are suitable. The amount of the oxide film to be formed is preferably 1.0 to 5.0 g / m ² , particularly 1.5 to 4.0 g / m ² .

  As the support used in the present invention, the substrate having the above-mentioned surface treatment and having an anodized film may be used as it is, but for further improvement in adhesion to the upper layer, hydrophilicity, resistance to contamination, heat insulation and the like. If necessary, it contains micropore enlargement treatment, micropore sealing treatment, and hydrophilic compound described in JP-A Nos. 2001-253181 and 2001-322365. A surface hydrophilization treatment immersed in an aqueous solution can be selected as appropriate.

  Suitable hydrophilic compounds for the hydrophilization treatment include polyvinylphosphonic acid, sulfonic acid group-containing compounds, saccharide compounds, citric acid, alkali metal silicates, potassium zirconium fluoride, phosphate / inorganic fluorine compounds, and the like. Can be mentioned.

  When using a support having insufficient surface hydrophilicity, such as a polyester film, as the support used in the present invention, it is desirable to apply a hydrophilic layer to make the surface hydrophilic. As the hydrophilic layer, at least one element selected from beryllium, magnesium, aluminum, silicon, titanium, boron, germanium, tin, zirconium, iron, vanadium, antimony, and a transition metal described in JP-A-2001-199175 A hydrophilic layer formed by coating a coating solution containing a colloid of oxide or hydroxide is preferred. Among these, a hydrophilic layer formed by applying a coating solution containing a silicon oxide or hydroxide colloid is preferable.

  In the present invention, before applying the heat-sensitive layer, an inorganic undercoat layer such as a water-soluble metal salt such as zinc borate described in JP-A No. 2001-322365 or, for example, carboxy as necessary. An organic subbing layer containing methylcellulose, dextrin, polyacrylic acid or the like can be provided. The undercoat layer can contain the infrared absorbing dye.

EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these.
[Example of support production]
Cleaning treatment was applied to molten metal of JIS A1050 alloy containing 99.5 mass% or more of aluminum and Fe 0.30 mass%, Si 0.10 mass%, Ti 0.02 mass%, and Cu 0.013 mass%. And cast. In the cleaning process, a degassing process was performed to remove unnecessary gases such as hydrogen in the molten metal, and a ceramic tube filter process was performed. The casting method was a DC casting method. The solidified 500 mm thick ingot was chamfered 10 mm from the surface and homogenized at 550 ° C. for 10 hours so as not to coarsen the intermetallic compound. Next, after hot rolling at 400 ° C. and intermediate annealing at 500 ° C. for 60 seconds in a continuous annealing furnace, cold rolling was performed to obtain an aluminum rolled plate having a plate pressure of 0.30 mm. By controlling the roughness of the rolling roll, the centerline average surface roughness Ra after cold rolling was controlled to 0.2 μm. Then, it applied to the tension leveler in order to improve planarity.

Next, the surface treatment for making a lithographic printing plate support was performed. First, in order to remove the rolling oil on the surface of the aluminum plate, degreasing treatment was carried out with a 10% by mass sodium aluminate aqueous solution at 50 ° C. for 30 seconds, and neutralization and smut removal treatment were carried out with a 30% by mass sulfuric acid aqueous solution at 50 ° C. for 30 seconds. Next, in order to improve the adhesion between the support and the heat-sensitive layer and to provide water retention to the non-image area, a so-called graining treatment was performed to roughen the surface of the support. An aqueous solution containing 1% by mass of nitric acid and 0.5% by mass of aluminum nitrate is kept at 45 ° C., and an aluminum web is allowed to flow in the aqueous solution, while an indirect power feeding cell has a current density of 20 A / dm ² and a duty ratio of 1: 1. Electrolytic graining was performed by applying an anode side electric quantity of 240 C / dm ² in an alternating waveform. Thereafter, an etching treatment was performed with a 10% by mass aqueous sodium aluminate solution at 50 ° C. for 30 seconds, and a 30% by mass sulfuric acid aqueous solution was subjected to neutralization and smut removal treatment at 50 ° C. for 30 seconds. Furthermore, in order to improve wear resistance, chemical resistance and water retention, an oxide film was formed on the support by anodic oxidation. An anodization of 2.5 g / m ² by using a 20% by weight sulfuric acid aqueous solution as an electrolyte at 35 ° C. and carrying out an aluminum web through the electrolyte and performing an electrolytic treatment at a direct current of 14 A / dm ² by an indirect power supply cell. A film was created.

Thereafter, a silicate treatment was performed in order to ensure hydrophilicity as a non-image portion of the printing plate. The treatment was carried in such a way that a No. 3 sodium silicate 1.5 mass% aqueous solution was kept at 70 ° C. so that the contact time of the aluminum web was 15 seconds and further washed with water. The adhesion amount of Si was 10 mg / m ² . The center line surface roughness Ra of the support produced as described above was 0.25 μm.

[Synthesis Example of Polymer Fine Particles Having Thermally Reactive Groups]
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. As a dispersant, 1.0 g of sodium dodecyl sulfate and 1.5 g of polyvinyl alcohol (KL05 manufactured by Nippon Synthetic Chemical Co., Ltd.) are added, and 0.45 g of ammonium persulfide is added as an initiator, followed by 45 g of glycidyl methacrylate and 45 g of styrene. Was dropped with a 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, adjusted to pH 6 with ammonia water, and finally purified water was added so that the non-volatile content was 15% by mass to obtain an aqueous dispersion of polymer fine particles having an epoxy group as a thermally reactive group. The particle size distribution of the polymer fine particles had a maximum value at a particle size of 80 nm.

  Here, the particle size distribution is obtained by taking an electron micrograph of polymer fine particles, measuring a total of 5000 fine particle sizes on the photograph, and a logarithmic scale between 0 and the maximum value of the obtained particle size measurement values. And the frequency of appearance of each particle size was plotted and obtained. 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.

[Synthesis example of microcapsules encapsulating a compound having a thermally reactive group]
As an oil phase component, 4.5 g of bis (vinyloxyethyl) ether of bisphenol A, an adduct of trimethylolpropane and xylylene diisocyanate (Takenate D-110N, manufactured by Mitsui Takeda Chemical Co., Ltd., microcapsule wall material) 5 g Millionate MR-200 (Nippon Polyurethane Co., Ltd. aromatic isocyanate oligomer, microcapsule wall material) 3.75 g, Infrared absorbing dye (IR-27 described herein) 1.5 g, Pionine A41C (Takemoto Yushi Co., Ltd.) ) Surfactant) 0.1 g was dissolved in 18.4 g of ethyl acetate. As an aqueous phase component, 37.5 g of a 4 mass% aqueous solution of PVA205 (Kuraray polyvinyl alcohol) was prepared. The oil phase component and the aqueous phase component were emulsified at 12000 rpm for 10 minutes using a homogenizer. Thereafter, a solution obtained by dissolving 0.38 g of tetraethylenepentamine (pentafunctional amine, microcapsule wall cross-linking agent) in 26 g of water was added, followed by stirring at 65 ° C. for 3 minutes while cooling with water. The microcapsule solution thus obtained had a solid content concentration of 24% by mass and an average particle size of 0.3 μm.

[Preparation of master A for heat-sensitive lithographic printing plate]
The following heat-sensitive layer coating solution containing the polymer fine particles obtained in the above synthesis example is bar-coated on the aluminum substrate obtained in the above production example, then oven-dried at 70 ° C. for 120 seconds, and the dry coating amount is 0.8 g / m. A master plate A for heat-sensitive lithographic printing plate ² was prepared.

<Thermosensitive layer coating solution>
Polymer fine particles obtained in synthesis example (solid content conversion) 10.0 g
Photothermal conversion agent (IR-10 described herein) 1.0 g
Polyacrylic acid (weight average molecular weight 25,000) 1.0 g
50.0 g of water

[Preparation of heat-sensitive lithographic printing plate precursor B]
The following heat-sensitive layer coating solution containing the microcapsules obtained in the above synthesis example is bar-coated on the aluminum substrate obtained in the above production example, and then dried in an oven at 100 ° C. for 60 seconds to dry-coat the heat-sensitive layer. A master B for heat-sensitive lithographic printing plate having an amount of 1.0 g / m ² was prepared.

<Thermosensitive layer coating solution>
35.4 g of water
9.0 g of microcapsule liquid obtained in the synthesis example
0.24 g of acid precursor (AI-7 as described herein)

[Preparation of dampening water]
According to the composition of the following Tables 1-3, the fountain solution used in Examples 1-9 and Comparative Examples 1-4 was prepared. The remainder of the composition of the fountain solution is water, and the unit of the content of each component shown in the table is mass% in the total mass of the fountain solution.
The fountain solution thus prepared was used for plate making and printing as follows.

[Print Evaluation]
Using the heat-sensitive lithographic printing plate precursors A and B thus obtained, plate making and printing were performed as follows. That is, a printing plate precursor is exposed to a Creo Trendsetter 3244VX equipped with a water-cooled 40W infrared semiconductor laser under the conditions of an output of 17 W, an outer drum rotation speed of 100 rpm, and a resolution of 2400 dpi, and then printed by Heidelberg without developing. It was attached to the cylinder of the machine SOR-M. 1 liter of dampening water having the composition shown in Tables 1 to 3 is supplied to each water supply tray, and GEOS-G (H) black ink (Dainippon Ink & Chemicals, Inc., tack value 12.2 at 25 ° C.) After supplying dampening water, supply ink while adjusting the cooling water temperature so that the temperature of the ink roller surface is 25 ° C. at a printing speed of 10,000 sheets per hour, and further supply paper. Was printed.
When using a new solution of fountain solution in this way, the number of printing papers required to complete on-press development, i.e., the number of sheets required to change from a completely black and dirty state to a normal printed matter, was examined, and the results were displayed. 1-3.
After printing is completed, dampening water is collected from the water supply tray and allowed to elapse for 3 days at room temperature of 25 ° C., then set again on the water supply tray of the printing press, and plate making and printing are performed again using new printing plate masters A and B. went. Thus, the same evaluation as the new solution was performed using the fatigue solution of the fountain solution, and the results are shown in Tables 1 to 3.

^*ＤＢＮＥ：1,1-ジブロモ-1-ニトロ-2-エタノール

^* DBNE: 1,1-dibromo-1-nitro-2-ethanol

^*ＤＢＮＥ：1,1-ジブロモ-1-ニトロ-2-エタノール

^* DBNE: 1,1-dibromo-1-nitro-2-ethanol

^*ＤＢＮＥ：1,1-ジブロモ-1-ニトロ-2-エタノール

^* DBNE: 1,1-dibromo-1-nitro-2-ethanol

  From the above results, it can be seen that according to the printing method of the present invention, the on-press development can be completed with a small amount of damaged paper, that is, with a small number of printing sheets. According to the printing method of the present invention, it can be seen that the processing fatigue of the fountain solution can be suppressed, and even when a so-called fatigue liquid is used as the fountain solution, the on-press developability is extremely low. Even if the fountain solution and the ink are supplied substantially simultaneously and the development process and the printing process are performed, the same effect can be obtained.

Claims (6)

  A step of recording an image on a lithographic printing plate precursor having a thermosensitive layer on a support, a bromonitroalcohol compound, a 1,2-benzisothiazolin-3-one compound, a p-hydroxybenzoic acid derivative, an azole compound, and A step of supplying dampening water containing at least one compound selected from the group consisting of heterocyclic alkylammonium salts to the plate surface and removing the heat-sensitive layer in the non-image area, and printing using the dampening water and ink A printing method using a heat-sensitive lithographic printing plate precursor characterized by comprising the steps of:   Bromonitroalcohol compounds are 2-bromo-2-nitropropane-1,3-diol, 1,1-dibromo-1-nitro-2-ethanol, 1,1-dibromo-1-nitro-2-propanol, And a printing method using the heat-sensitive lithographic printing plate precursor according to claim 1, wherein the printing plate is selected from 3-bromo-3-nitropentane-2,4-diol. The printing method using the heat-sensitive lithographic printing plate precursor according to claim 1, wherein the 1,2-benzisothiazolin-3-one compound is a compound represented by the following general formula.

(In the formula, R represents a hydrogen atom or an alkyl group, X represents an alkyl group, an alkoxy group, or a halogen atom, and n represents 0 or an integer of 1 to 4).   p-hydroxybenzoic acid derivatives are isobutyl p-hydroxybenzoate, isopropyl p-hydroxybenzoate, ethyl p-hydroxybenzoate, butyl p-hydroxybenzoate, propyl p-hydroxybenzoate, methyl p-hydroxybenzoate, And a printing method using the heat-sensitive lithographic printing plate precursor according to claim 1, which is selected from vinyl p-hydroxybenzoate.   The azole compound is α- (4-chlorophenyl) -α- (1-cyclopropylethyl) -1H-1,2,4-triazole-1-ethanol, α- [2- (4-chlorophenyl) ethyl]- α- (1,1-dimethylethyl) -1H-1,2,4-triazole-1-ethanol, and 1-[[2- (2,4-dichlorophenyl) -4-n-propyl-1,3- The printing method using the heat-sensitive lithographic printing plate precursor according to claim 1, which is selected from dioxolan-2-yl] methyl] -1H-1,2,4-triazole.   The printing method using the heat-sensitive lithographic printing plate precursor according to claim 1, wherein the alkyl group of the heterocyclic alkylammonium salt is an alkyl group having 8 to 18 carbon atoms.