JP2002229186A - Original plate of planographic printing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a positive original plate of a planographic printing plate for an IR laser for direct plate making excellent in latitude and scuffing resis tance in image formation by development and capable of forming an image of superior image quality. SOLUTION: The original plate is obtained by disposing a positive recording layer containing (A) a water-insoluble and alkali-soluble resin, (B) an IR absorber and (C) an organic quaternary ammonium salt and having solubility in an alkaline aqueous solution increased by exposure with infrared laser light on a base. A compound having at least one of aryl and carbonyl groups in its molecule is preferably used as (C) the organic quaternary ammonium salt.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image recording material usable as an offset printing master, and more particularly to a positive type lithographic printing plate precursor for an infrared laser for so-called direct plate making that can be directly made from a digital signal of a computer or the like.

[0002]

2. Description of the Related Art In recent years, lasers have been remarkably developed.
2. Description of the Related Art Semiconductor lasers are easily available in small size with high output. These lasers are very useful as an exposure light source when making a plate directly from digital data of a computer or the like.

[0003] Positive lithographic printing plate materials for infrared lasers are:
An essential component is an alkaline aqueous solution-soluble binder resin and an IR dye or the like that absorbs light and generates heat. The IR dye or the like dissolves in the unexposed area (image area) by interaction with the binder resin. In the exposed area (non-image area), the generated heat weakens the interaction between the IR dye and the binder resin and dissolves in the alkaline developer to form a lithographic printing plate in the exposed area (non-image area). I do. However, in such a positive type lithographic printing plate material for an infrared laser, the solubility between the unexposed portion (image portion) in the developing solution and the solubility in the exposed portion (non-image portion) under various use conditions is reduced. However, there is a problem that excessive development or poor development is likely to occur due to fluctuations in use conditions. In addition, even when the surface condition slightly changes due to touching the surface during handling, the unexposed portion (image portion) dissolves during development to form scratch marks, which causes deterioration of printing durability and poor adhesion. There was a problem.

[0004] Such a problem stems from an essential difference in the plate making mechanism between the positive lithographic printing plate material for infrared laser and the positive lithographic printing plate material made by UV exposure. That is, in a positive lithographic printing plate material made by UV exposure, a binder resin soluble in an aqueous alkali solution and an onium salt or a quinonediazide compound are essential components. In the image area), not only does it act as a dissolution inhibitor due to the interaction with the binder resin, but in the exposed area (non-image area), it is decomposed by light to generate acid and acts as a dissolution promoter. Things. On the other hand, the IR dye or the like in the positive type lithographic printing plate material for an infrared laser only acts as a dissolution inhibitor in an unexposed portion (image portion) and does not promote dissolution in an exposed portion (non-image portion). . Therefore, in order to obtain a difference in solubility between the unexposed portion and the exposed portion in the infrared laser positive lithographic printing plate material, a binder resin having high solubility in an alkali developing solution must be used in advance. Not get
The state before development becomes unstable.

Various dissolution inhibitors for improving the development resistance have been proposed, but there are few which can quickly release the suppression effect by exposure. For the purpose of increasing the solubility of an unexposed portion (image portion) in a developing solution without lowering the developability of an exposed portion (non-image portion), for example, EP 950517 discloses a method using a siloxane-based surfactant. And Japanese Patent Application Laid-Open No. 10-26851 discloses a method using a sulfonic acid ester or the like as a dissolution inhibitor. These contribute to improving the development resistance of the image portion of the recording layer to some extent, but have sufficient solubility between the unexposed portion and the exposed portion so that a sharp and good image can be formed regardless of fluctuations in the activity of the developer. It is hard to say that the difference has been achieved.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide excellent latitude and scratch resistance during image formation by development,
An object of the present invention is to provide a positive lithographic printing plate precursor for infrared laser for direct plate making which can form an image of excellent quality.

[0007]

The inventors of the present invention have conducted intensive studies, and as a result, have developed an excellent development latitude by coexisting an organic quaternary ammonium salt as a dissolution inhibitor in the same layer as a water-insoluble and alkali-soluble resin. They have found that a lithographic printing plate can be obtained, and have completed the present invention.

That is, the lithographic printing plate precursor according to the present invention comprises: (A) a water-insoluble and alkali-soluble resin;
A positive recording layer containing an infrared absorbent and (C) an organic quaternary ammonium salt and having increased solubility in an alkaline aqueous solution by exposure to an infrared laser is provided. As the organic quaternary ammonium salt (C) used herein, those having at least one group selected from an aryl group and a carbonyl group in the molecule are preferable from the viewpoint of effects.

Although the mechanism of action of the present invention is not clear, the recording layer contains (A) a water-insoluble and alkali-soluble resin (hereinafter, appropriately referred to as an alkali-soluble resin) and (C)
By allowing the organic quaternary ammonium salt to coexist in the same layer, a dry film is formed in an energy-stable state, that is, in a state in which interaction between both compounds works. In the unexposed area,
Since the alkali dissolution suppressing effect is obtained by the formation of this interaction, excellent alkali development resistance is exhibited as compared with the case of using (A) the alkali-soluble resin alone. On the other hand, in the exposed area, (C) the organic quaternary ammonium salt has a three-dimensional structure around the nitrogen cation due to its chemical structure, and (A) the interaction force itself with the alkali-soluble resin is relatively small. In the region where (B) the infrared absorbing agent generates heat by exposure to the infrared laser, the interaction is efficiently released. In addition, since the (C) organic quaternary ammonium salt used is itself a low molecular compound, it can be easily dispersed in an alkaline aqueous solution in a state where the interaction is released, and the dissolution accelerating property can be obtained. For this reason, by using (C) an organic quaternary ammonium salt, there is a large difference in solubility between an unexposed portion and an exposed portion in an alkali developing solution, and a good image can be formed regardless of the concentration of the developing solution. It is assumed that

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. The lithographic printing plate precursor according to the invention needs to contain (A) a water-insoluble and alkali-soluble resin, (B) an infrared absorber and (C) an organic quaternary ammonium salt in the recording layer. less than,
Components constituting the recording layer will be described sequentially.

[(C) Organic quaternary ammonium salt] The (C) organic quaternary ammonium salt used in the present invention is not particularly limited, and a quaternary ammonium salt having a known organic group is appropriately selected and used. be able to. 4 suitable for the present invention
The quaternary ammonium salt is a low molecular weight compound and is a monomer or an oligomer. Above all, from the viewpoint of the effect, the organic group preferably has at least one of an aryl group and a carbonyl group in the molecule, and more preferably has both the aryl group and the carbonyl group. Examples of the organic quaternary ammonium salt compound that can be suitably used in the present invention include those represented by the following general formula (I).

[0012]

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In the formula, R ¹ , R ² , R ³ and R ⁴ are each independently an organic group having at least one carbon atom, and these may be linked to each other to form a ring. As a preferred embodiment of the organic quaternary ammonium salt represented by the general formula (I),
A compound in which at least one of R ¹ , R ² , R ³ , and R ⁴ is a functional group having a partial structure shown below.

[0014]

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[0015] In the formula, Ar ¹ represents an aryl group, R ^5, R
⁶ and R ⁷ each independently represent a hydrogen atom or an organic group having at least one carbon atom, at least two of which are selected from organic groups that are not hydrogen atoms. R ⁵ , R ⁶ , R
⁷ may be linked to each other to form a ring. In another preferred embodiment of the organic quaternary ammonium salt represented by the general formula (I), at least one of R ¹ , R ² , R ³ , and R ⁴ is selected from the following functional group (hereinafter referred to as group A). The compound selected is mentioned.

[0016]

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Wherein R ⁸ , R ⁹ and R ¹⁰ are each independently
An organic group having at least one hydrogen atom or carbon atom, at least two of which are selected from organic groups that are not hydrogen atoms; R ⁸ , R ⁹ and R ¹⁰ may be linked to each other to form a ring. As more preferred embodiments of the organic quaternary ammonium salt represented by the general formula (I), R ¹ , R ² ,
A compound in which at least one of R ³ and R ⁴ is selected from the following functional group (referred to as group B) is exemplified.

[0018]

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In the formula, Ar ² represents an aryl group, R ¹¹ ,
R ¹² each independently represents a hydrogen atom or an organic group having at least one carbon atom, and Ar ² , R ¹¹ and R ¹² may be linked to each other to form a ring. R ¹³ , R ¹⁴ , and R ¹⁵ each independently represent a hydrogen atom or an organic group having at least one carbon atom, and at least one of them is a non-aromatic cyclic substituent, or R ¹³ , R ^{15 In} this embodiment, two adjacent ones of R ¹⁵ and R ¹⁵ are connected to each other to form a ring. As the most preferred embodiment of the organic quaternary ammonium salt represented by the general formula (I), a compound in which R ⁸ is an aryl group in the functional group of Group A, and R ¹ , R ² , R ³ , and R ⁴ , At least two of which are functional groups selected from the group A and the group B, and more preferably, a functional group selected from the group A and a functional group selected from the group B are each 1 Compounds having one by one. Specific examples of preferred organic quaternary ammonium salts that can be used in the present invention are shown below, but the present invention is not limited thereto.

[0020]

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[0021]

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These organic quaternary ammonium salts (C) are preferably contained in an amount of 0.1 to 40% by weight, and particularly in a range of 0.5 to 10% by weight, based on the total solid content of the positive recording layer. Is preferred. If the content is too small, the effect of the present invention is hardly obtained, and if the content is too large, the content of the alkali-soluble resin used in combination is relatively reduced, and the abrasion resistance during printing may be reduced. Come.

[(A) Water-insoluble and alkali-soluble resin] The water-insoluble and alkali-soluble resin used in the present invention is not particularly limited as long as it is a conventionally known one. It is preferable that the polymer compound has a functional group of either 2) sulfonamide group or (3) active imide group in the molecule. Examples of the alkali-soluble polymer that can be suitably used in the present invention include, for example, the following, but are not limited thereto.

(1) Examples of the high molecular compound having a phenolic hydroxyl group include phenol formaldehyde resin, m-cresol formaldehyde resin, p-cresol formaldehyde resin, m- / p-mixed cresol formaldehyde resin, 2,3-xylenol Formaldehyde resin, 2,5-xylenol formaldehyde resin, 3,5-xylenol formaldehyde resin,
Phenol / cresol (m-, p- or m- / p-
Mixed formaldehyde resin, phenol / xylenol mixed formaldehyde resin, xylenol / cresol (m-, p-, or m- / p-
Novolak resin such as mixed formaldehyde resin, phenol / cresol / xylenol mixed formaldehyde resin, and pyrogallol acetone resin.

Further, as the alkali-soluble resin having a phenolic hydroxyl group, US Pat. No. 4,123,
As described in the specification of JP-A-279, a condensation polymer of phenol having a C3-8 alkyl group as a substituent, such as t-butylphenol formaldehyde resin and octylphenol formaldehyde resin, and formaldehyde can be mentioned. As the high molecular compound having a phenolic hydroxyl group, a high molecular compound having a phenolic hydroxyl group in a side chain is preferably used.
As the high molecular compound having a phenolic hydroxyl group in the side chain, a polymerizable monomer composed of a low molecular compound having at least one unsaturated bond capable of polymerizing with the phenolic hydroxyl group may be homopolymerized, or another polymerizable monomer may be used. Examples include a polymer compound obtained by copolymerizing a monomer.

Examples of the polymerizable monomer having a phenolic hydroxyl group include acrylamide, methacrylamide, acrylate, methacrylate, and hydroxystyrene having a phenolic hydroxyl group. Specifically, N- (2-hydroxyphenyl) acrylamide, N- (3-hydroxyphenyl) acrylamide, N- (4-hydroxyphenyl) acrylamide, N- (2-hydroxyphenyl) methacrylamide, N- (3 -Hydroxyphenyl) methacrylamide, N- (4-hydroxyphenyl) methacrylamide, o-hydroxyphenyl acrylate, m-hydroxyphenyl acrylate, p-hydroxyphenyl acrylate, o-hydroxyphenyl methacrylate,
m-hydroxyphenyl methacrylate, p-hydroxyphenyl methacrylate, o-hydroxystyrene,
m-hydroxystyrene, p-hydroxystyrene, 2
-(2-hydroxyphenyl) ethyl acrylate, 2
-(3-hydroxyphenyl) ethyl acrylate, 2
-(4-hydroxyphenyl) ethyl acrylate, 2
-(2-hydroxyphenyl) ethyl methacrylate,
2- (3-hydroxyphenyl) ethyl methacrylate, 2- (4-hydroxyphenyl) ethyl methacrylate and the like can be suitably used. Such resins having a phenolic hydroxyl group may be used in combination of two or more. No. 4,123,279.
As described in the specification, a condensation polymer of phenol and formaldehyde having an alkyl group having 3 to 8 carbon atoms as a substituent, such as t-butylphenol formaldehyde resin and octylphenol formaldehyde resin, may be used in combination. Good.

(2) Examples of the alkali-soluble resin having a sulfonamide group include a polymer compound obtained by homopolymerizing a polymerizable monomer having a sulfonamide group or copolymerizing the monomer with another polymerizable monomer. Can be Examples of the polymerizable monomer having a sulfonamide group include, in one molecule, at least one sulfonamide group —NH—SO ₂ — in which at least one hydrogen atom is bonded to a nitrogen atom, and at least one polymerizable unsaturated bond. And a polymerizable monomer composed of a low-molecular compound. Among them, acryloyl group, allyl group, or vinyloxy group,
Low molecular weight compounds having a substituted or monosubstituted aminosulfonyl group or a substituted sulfonylimino group are preferred. Examples of such a compound include compounds represented by the following general formulas (a) to (e).

[0028]

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In the formula, X ¹ and X ² each represent —O— or —NR ⁷ —. R ¹ and R ⁴ each represent a hydrogen atom or —CH ₃ . R ² , R ⁵ , R ⁹ , R ¹² and R ¹⁶ each represent an optionally substituted alkylene group having 1 to 12 carbon atoms, a cycloalkylene group, an arylene group or an aralkylene group. R ³ , R ⁷ and R ¹³ each represent a hydrogen atom, an alkyl group having 1 to 12 carbon atoms which may have a substituent, a cycloalkyl group, an aryl group or an aralkyl group. R ⁶ and R ¹⁷ each represent an optionally substituted alkyl group having 1 to 12 carbon atoms, a cycloalkyl group, an aryl group or an aralkyl group. R ⁸ ,
R ¹⁰ and R ¹⁴ represent a hydrogen atom or —CH ₃ . R ¹¹ and R ¹⁵ each represent a single bond or an optionally substituted alkylene group having 1 to 12 carbon atoms, a cycloalkylene group, an arylene group or an aralkylene group. Y ¹ and Y ² each represent a single bond or —CO—. Specifically, m-aminosulfonylphenyl methacrylate, N
-(P-Aminosulfonylphenyl) methacrylamide, N- (p-aminosulfonylphenyl) acrylamide and the like can be preferably used.

(3) The alkali-soluble resin having an active imide group is preferably a resin having an active imide group represented by the following formula in the molecule. Active imide group, and a polymerizable monomer obtained by homopolymerizing a polymerizable monomer comprising a low molecular compound having at least one polymerizable unsaturated bond, or by copolymerizing the monomer with another polymerizable monomer. No.

[0031]

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As such a compound, specifically,
N- (p-toluenesulfonyl) methacrylamide, N
-(P-Toluenesulfonyl) acrylamide and the like can be suitably used.

The alkali-soluble resin of the present invention is preferably a novolak resin. Further, a polymer compound obtained by polymerizing two or more of the polymerizable monomer having a phenolic hydroxyl group, the polymerizable monomer having a sulfonamide group, and the polymerizable monomer having an active imide group, or a polymer compound of these two or more types It is preferable to use a polymer compound obtained by copolymerizing a polymerizable monomer with another polymerizable monomer. A polymerizable monomer having a phenolic hydroxyl group, a polymerizable monomer having a sulfonamide group and / or
Alternatively, when a polymerizable monomer having an active imide group is copolymerized, the compounding weight ratio of these components is preferably in the range of 50:50 to 5:95, and is in the range of 40:60 to 10:90. Is particularly preferred.

In the present invention, the alkali-soluble resin is a copolymer of a polymerizable monomer having a phenolic hydroxyl group, a polymerizable monomer having a sulfonamide group, or a polymerizable monomer having an active imide group, and another polymerizable monomer. In the case of coalescence, it is preferable that the monomer for imparting alkali solubility is contained in an amount of 10 mol% or more, and 20 mol% or more.
Those containing the above are more preferable. 10 mol% copolymer component
If less, alkali solubility tends to be insufficient,
The effect of improving the development latitude may not be sufficiently achieved.

Examples of the monomer components to be copolymerized with the polymerizable monomer having a phenolic hydroxyl group, the polymerizable monomer having a sulfonamide group, or the polymerizable monomer having an active imide group include the following (m1) to (m1)
The monomers described in 2) can be used, but are not limited thereto. (M1) For example, acrylates and methacrylates having an aliphatic hydroxyl group such as 2-hydroxyethyl acrylate or 2-hydroxyethyl methacrylate. (M2) methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, amyl acrylate,
Alkyl acrylates such as hexyl acrylate, octyl acrylate, benzyl acrylate, 2-chloroethyl acrylate, glycidyl acrylate and N-dimethylaminoethyl acrylate; (M3) Methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, amyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, methacrylic acid-2-
Alkyl methacrylates such as chloroethyl, glycidyl methacrylate and N-dimethylaminoethyl methacrylate; (M4) acrylamide, methacrylamide, N-methylolacrylamide, N-ethylacrylamide, N
-Hexyl methacrylamide, N-cyclohexyl acrylamide, N-hydroxyethyl acrylamide, N
Acrylamide or methacrylamide such as -phenylacrylamide, N-nitrophenylacrylamide, and N-ethyl-N-phenylacrylamide. (M5) Vinyl ethers such as ethyl vinyl ether, 2-chloroethyl vinyl ether, hydroxyethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, octyl vinyl ether, and phenyl vinyl ether.

(M6) Vinyl esters such as vinyl acetate, vinyl chloroacetate, vinyl butyrate and vinyl benzoate. (M7) Styrenes such as styrene, α-methylstyrene, methylstyrene, and chloromethylstyrene. (M8) Vinyl ketones such as methyl vinyl ketone, ethyl vinyl ketone, propyl vinyl ketone, and phenyl vinyl ketone. (M9) Olefins such as ethylene, propylene, isobutylene, butadiene and isoprene. (M10) N-vinylpyrrolidone, N-vinylcarbazole, 4-vinylpyridine, acrylonitrile, methacrylonitrile and the like. (M11) Unsaturated imides such as maleimide, N-acryloylacrylamide, N-acetylmethacrylamide, N-propionylmethacrylamide, N- (p-chlorobenzoyl) methacrylamide. (M12) Unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic anhydride and itaconic acid.

In the present invention, when the alkali-soluble resin is a homopolymer or copolymer of the polymerizable monomer having a phenolic hydroxyl group, the polymerizable monomer having a sulfonamide group, or the polymerizable monomer having an active imide group, Those having a weight average molecular weight of 2,000 or more and a number average molecular weight of 500 or more are preferred. More preferably, the weight average molecular weight is 5,000 to 300,000, the number average molecular weight is 800 to 250,000, and the degree of dispersion (weight average molecular weight / number average molecular weight) is 1.1 to 10. . In the present invention, when the alkali-soluble resin is a resin such as a phenol formaldehyde resin and a cresol aldehyde resin, the weight average molecular weight is 500 to 2
000 and a number average molecular weight of 200 to 10,000.
0 is preferred.

Each of these alkali-soluble resins is 1
May be used in combination of two or more types,
It is used in an amount of 30 to 99% by weight, preferably 40 to 95% by weight, particularly preferably 50 to 90% by weight, based on the total solid content of the recording layer. 3 alkali-soluble resin added
If the content is less than 0% by weight, the durability of the recording layer deteriorates.
If it exceeds 99% by weight, it is not preferable in terms of both sensitivity and durability.

[(B) Infrared absorbing agent] The infrared absorbing agent used in the present invention is not particularly limited as long as it is a substance that absorbs infrared light and generates heat, and is known as an infrared absorbing dye or an infrared absorbing pigment. Various pigments or dyes can be used. Examples of pigments include commercially available pigment and color index (CI) handbook, “Latest Pigment Handbook” (edited by The Japan Pigment Technical Association, 1977), “Latest Pigment Application Technology” (CMC Publishing, 1986), “printing”. Pigments described in "Ink Technology" published by CMC, 1984) can be used. As pigment types, black pigments,
Yellow pigments, orange pigments, brown pigments, red pigments, violet pigments, blue pigments, green pigments, fluorescent pigments, metal powder pigments, and other polymer-bound pigments. Specifically, insoluble azo pigments, azo lake pigments, condensed azo pigments, chelated azo pigments, phthalocyanine pigments, anthraquinone pigments, perylene and perinone pigments, thioindigo pigments, quinacridone pigments, dioxazine pigments, isoindolinone pigments And quinophthalone pigments, dyed lake pigments, azine pigments, nitroso pigments, nitro pigments, natural pigments, fluorescent pigments, inorganic pigments, carbon black, and the like.

These pigments may be used without surface treatment, or may be used after surface treatment. Methods of surface treatment include a method of surface coating a resin or wax, a method of attaching a surfactant, and a reactive substance (for example, a silane coupling agent, an epoxy compound, or a polyisocyanate).
Can be conceived on the surface of the pigment. The above surface treatment methods are described in "Properties and Applications of Metallic Soaps" (Koshobo),
It is described in "Printing Ink Technology" (CMC Publishing, 1984) and "Latest Pigment Application Technology" (CMC Publishing, 1986). Pigment particle size is 0.01 μm to 10 μm
And more preferably in the range of 0.05 μm to 1 μm, particularly 0.1 μm to 1 μm.
It is preferably in the range of μm. Pigment particle size is 0.0
If it is less than 1 μm, the dispersion is not preferred in terms of stability in the coating solution for the recording layer, and if it exceeds 10 μm, the uniformity of the recording layer is not preferred. As a method for dispersing the pigment, a known dispersion technique used in the production of ink or toner can be used. As the disperser, an ultrasonic disperser,
Sand mills, attritors, pearl mills, super mills, ball mills, impellers, dispersers, KD mills, colloid mills, dynatrons, three-roll mills, pressure kneaders and the like can be mentioned. Details are described in "Latest Pigment Application Technology" (CMC Publishing, 1986).

As the dye, commercially available dyes and literatures (for example, "Dye Handbook" edited by The Society of Synthetic Organic Chemistry, published in 1970)
The known ones described in (1) can be used. Specific examples include dyes such as azo dyes, metal complex salt azo dyes, pyrazolone azo dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinone imine dyes, methine dyes, and cyanine dyes. In the present invention, among these pigments or dyes, those that absorb infrared light or near-infrared light are particularly preferable because they are suitable for use in lasers that emit infrared light or near-infrared light.

As such a pigment absorbing infrared light or near infrared light, carbon black is preferably used. Dyes that absorb infrared light or near infrared light include, for example, JP-A-58-125246 and JP-A-59-125246.
-84356, JP-A-59-202829, JP-A-60-78787 and the like.
JP-A-58-173696, JP-A-58-18169
0, methine dyes described in JP-A-58-194595, JP-A-58-112793, and JP-A-58-112793.
Naphthoquinone dyes described in JP-A-224793, JP-A-59-48187, JP-A-59-73996, JP-A-60-52940 and JP-A-60-63744; And the cyanine dyes described in British Patent No. 434,875.

Also, US Pat.
No. 938 is also preferably used, and substituted arylbenzo (thio) pyrylium salts described in U.S. Pat. No. 3,881,924;
No. 42645 (U.S. Pat. No. 4,327,169);
No. 51, No. 58-220143, No. 59-41363
Nos. 59-84248, 59-84249, 59-146063, and 59-146061 and pyrylium compounds described in JP-A-59-2161.
No. 46, a cyanine dye disclosed in U.S. Pat. No. 4,283,4.
No. 75, pentamethine thiopyrylium salt and the like, and Japanese Patent Publication Nos. 5-135514 and 5-19702, pyrylium compounds and the like, as commercial products, Epolin III-178 manufactured by Eporin, Epoli
Ght III-130, Epollight III-125 and the like are particularly preferably used.

Another particularly preferred example of the dye is a near-infrared absorbing dye described as formulas (I) and (II) in US Pat. No. 4,756,993. These pigments or dyes are used in an amount of 0.01 to 50% by weight, preferably 0.1 to 10% by weight, particularly preferably 0.5 to 10% by weight, in the case of dyes, Particularly preferred is 3.1.
It can be added to the printing plate material at a ratio of 10 to 10% by weight. If the amount of the pigment or dye is less than 0.01% by weight, the sensitivity is lowered, and if it exceeds 50% by weight, the uniformity of the recording layer is lost and the durability of the recording layer is deteriorated. These dyes or pigments may be added to the same layer as other components, or a separate layer may be provided and added thereto. If it is a separate layer, it is desirable to add it to a layer adjacent to the layer containing a substance which substantially reduces the solubility of the binder when it is thermally decomposable and does not decompose. The dye or pigment and the binder resin are preferably in the same layer, but may be in different layers.

[Other Components] In forming the positive recording layer of the present invention, various additives can be further added as necessary. For example, it is not possible to use a substance that is thermally decomposable, such as an onium salt, an o-quinonediazide compound, an aromatic sulfone compound, and an aromatic sulfonic acid ester compound, and that substantially reduces the solubility of an alkali-soluble resin when not decomposed. This is preferable from the viewpoint of improving the dissolution inhibiting property of the image area in the developer. Examples of the onium salt include a diazonium salt, an ammonium salt, a phosphonium salt, an iodonium salt, a sulfonium salt, a selenonium salt, and an arsonium salt.

Suitable onium salts used in the present invention include, for example, SI Schlesinger,
Photogr. Sci. Eng., 18, 387 (1974), TS Bal et a
1, Polymer, 21, 423 (1980), JP-A-5-158230
No. 4,069,055 diazonium salt described in U.S. Pat.
No. 4,069,056, ammonium salt described in the specification of JP-A-3-140140, DC Necker et al, Macromolecul
es, 17, 2468 (1984), CS Wen et al, Teh, Proc. Co.
nf.Rad. Curing ASIA, p478 Tokyo, Oct (1988), U.S. Pat.Nos. 4,069,055 and 4,069,056, phosphonium salts described in JVCrivello et al, Macromorecules, 10
(6), 1307 (1977), Chem. & Eng. News, Nov. 28, p31.
(1988), EP 104,143, U.S. Patent 339,049
No. 410,201, JP-A-2-150848, JP-A-2-2-2965
Iodonium salt described in No. 14, JVCrivello et al, P
olymer J. 17, 73 (1985), JV Crivello et al. J.
Org.Chem., 43, 3055 (1978), WR Watt et al, J. P.
olymer Sci., Polymer Chem. Ed., 22, 1789 (1984),
JV Crivello et al, Polymer Bull., 14, 279 (198
5), JV Crivello et al, Macromorecules, 14 (5),
1141 (1981), JV Crivello et al, J. Polymer Sci.,
Polymer Chem. Ed., 17, 2877 (1979), European Patent No. 37
0,693, 233,567, 297,443, 297,442
Nos. 4,933,377, 3,902,114, 410,
No. 201, No. 339,049, No. 4,760,013, No. 4,734,444
No. 2,833,827, German Patent No. 2,904,626, No. 3,60
Nos. 4,580 and 3,604,581, sulfonium salts described in J.
V. Crivello et al, Macromorecules, 10 (6), 1307 (19
77), JV Crivello et al, J. Polymer Sci., Polyme
r Chem. Ed., 17, 1047 (1979), a selenonium salt, CS Wen et al, Teh, Proc. Conf. Rad. Curing AS
IA, p478 Tokyo, Oct (1988). Of the onium salts, diazonium salts are particularly preferred. Particularly preferred diazonium salts include those described in JP-A-5-158230.

As the counter ion of the onium salt, tetrafluoroboric acid, hexafluorophosphoric acid, triisopropylnaphthalenesulfonic acid, 5-nitro-o-toluenesulfonic acid,
-Sulfosalicylic acid, 2,5-dimethylbenzenesulfonic acid, 2,4,6-trimethylbenzenesulfonic acid, 2
-Nitrobenzenesulfonic acid, 3-chlorobenzenesulfonic acid, 3-bromobenzenesulfonic acid, 2-fluorocaprylnaphthalenesulfonic acid, dodecylbenzenesulfonic acid, 1-naphthol-5-sulfonic acid, 2-methoxy-4-hydroxy-5- Benzoyl-benzenesulfonic acid, paratoluenesulfonic acid and the like can be mentioned. Among them, alkyl aromatic sulfonic acids such as hexafluorophosphoric acid, triisopropylnaphthalenesulfonic acid and 2,5-dimethylbenzenesulfonic acid are particularly preferable.

Preferred quinonediazides include o-quinonediazide compounds. The o-quinonediazide compound used in the present invention is a compound having at least one o-quinonediazide group, which increases alkali solubility by thermal decomposition, and can be a compound having various structures. In other words, o-quinonediazide assists the solubility of the light-sensitive material system by both the effect of losing the ability to suppress the dissolution of the binder by thermal decomposition and the fact that o-quinonediazide itself changes to an alkali-soluble substance. Examples of the o-quinonediazide compound used in the present invention include those described in J. Am. The compounds described in "Light-Sensitive Systems" by John Coleyer (John Wiley & Sons. Inc.), pages 339-352, can be used, but are particularly suitable for reacting with various aromatic polyhydroxy compounds or aromatic amino compounds. Sulfonic acid esters or amides of quinonediazides are preferred. Also, benzoquinone (1,2) -diazidosulfonic acid chloride or naphthoquinone- (1,1) described in JP-B-43-28403.
2) esters of -diazide-5-sulfonic acid chloride with pyrogallol-acetone resin, U.S. Pat. No. 3,046,12
The esters of benzoquinone- (1,2) -diazidesulfonic acid chloride or naphthoquinone- (1,2) -diazide-5-sulfonic acid chloride and phenol-formaldehyde resin described in No. 0 and 3,188,210 are also used. It is preferably used.

Further, esters of naphthoquinone- (1,2) -diazide-4-sulfonic acid chloride with phenol formaldehyde resin or cresol-formaldehyde resin, naphthoquinone- (1,2) -diazide-
Esters of 4-sulfonic acid chloride with pyrogallol-acetone resin are likewise preferably used. Other useful o-quinonediazide compounds are reported and known in numerous patents. For example, JP-A-47-5303, JP-A-48-63802, JP-A-48-63803, JP-A-48-96
No. 575, JP-A-49-38701, JP-A-48-13354, JP-B-41-11222, JP-B-45-9610, JP-B-49-17481
No. 2,797,213, No. 3,454,400, No. 3,544,323, No. 3,573,917, No. 3,674,495
No. 3,785,825; British Patent No. 1,227,602;
Nos. 1,251,345, 1,267,005, 1,329,888,
No. 1,330,932, and German Patent No. 854,890, etc. can be mentioned.

The amount of the o-quinonediazide compound added is preferably 1 to 50% by weight, more preferably 5 to 30% by weight, particularly preferably 10 to 3% by weight, based on the total solids of the printing plate material.
The range is 0% by weight. These compounds can be used alone, but may be used as a mixture of several kinds.

The amount of additives other than the o-quinonediazide compound is preferably 1 to 50% by weight, more preferably 5 to 30% by weight, and particularly preferably 10 to 30% by weight. It is preferable that the additive and the binder of the present invention are contained in the same layer.

For the purpose of further improving the sensitivity, cyclic acid anhydrides, phenols and organic acids can be used in combination. Examples of the cyclic acid anhydride include phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, 3,6-endooxy-Δ4-tetrahydrophthalic anhydride, and tetrachlorophthalic anhydride described in U.S. Pat. No. 4,115,128. , Maleic anhydride, chloromaleic anhydride, α-phenylmaleic anhydride, succinic anhydride, pyromellitic anhydride, and the like. As phenols, bisphenol A, p-nitrophenol, p-nitrophenol
Ethoxyphenol, 2,4,4'-trihydroxybenzophenone, 2,3,4-trihydroxybenzophenone, 4-hydroxybenzophenone, 4,4 ', 4 "
-Trihydroxytriphenylmethane, 4,4 ',
3 ", 4" -tetrahydroxy-3,5,3 ', 5'-
Tetramethyltriphenylmethane and the like can be mentioned. Further, as organic acids, JP-A-60-88942,
Sulfonic acids, such as those described in
There are sulfinic acids, alkyl sulfates, phosphonic acids, phosphoric esters and carboxylic acids, and specifically, p-toluenesulfonic acid, dodecylbenzenesulfonic acid, p-toluenesulfinic acid, ethyl sulfate, phenylphosphonic acid, Phenylphosphinic acid, phenyl phosphate, diphenyl phosphate, benzoic acid, isophthalic acid, adipic acid, p-toluic acid, 3,4-dimethoxybenzoic acid, phthalic acid, terephthalic acid, 4-cyclohexene-
Examples thereof include 1,2-dicarboxylic acid, erucic acid, lauric acid, n-undecanoic acid, and ascorbic acid. The proportion of the above cyclic acid anhydride, phenols and organic acids in the printing plate material is preferably 0.05 to 20% by weight,
It is more preferably 0.1 to 15% by weight, particularly preferably 0.1 to 10% by weight.

In the recording layer coating solution according to the present invention,
Japanese Patent Application Laid-Open No.
Nonionic surfactants as described in JP-A-2-251740 and JP-A-3-208514, and amphoteric as described in JP-A-59-121044 and JP-A-4-13149. Surfactant, EP950
It is possible to add a siloxane compound as described in JP-A-517, and a fluorine-containing monomer copolymer as described in JP-A-11-288093. Specific examples of the nonionic surfactant include sorbitan tristearate, sorbitan monopalmitate,
Sorbitan triolate, stearic acid monoglyceride, polyoxyethylene nonyl phenyl ether and the like can be mentioned. Specific examples of the surfactant include alkyl di (aminoethyl) glycine, alkyl polyaminoethyl glycine hydrochloride, 2-alkyl-N-carboxyethyl-N-hydroxyethylimidazolinium betaine and N
-Tetradecyl-N, N-betaine type (for example, trade name “Amogen K”: manufactured by Dai-ichi Kogyo Co., Ltd.) and the like. As the siloxane-based compound, a block copolymer of dimethylsiloxane and polyalkylene oxide is preferable. Specific examples include DBE-224, manufactured by Chisso Corporation.
DBE-621, DBE-712, DBP-732, D
BP-534, manufactured by Tego, Germany, Tego Glide
And polyalkylene oxide-modified silicones such as 100. The proportion of the nonionic surfactant and the amphoteric surfactant in the printing plate material is 0.05 to 1
5% by weight is preferred, more preferably 0.1-5% by weight
It is.

In the recording layer of the present invention, a printing-out agent for obtaining a visible image immediately after heating by exposure, and a dye or pigment as an image coloring agent can be added. Representative examples of the printing-out agent include a combination of a compound that releases an acid by heating upon exposure (photoacid releasing agent) and an organic dye that can form a salt. Specifically, combinations of o-naphthoquinonediazide-4-sulfonic acid halogenide and salt-forming organic dyes described in JP-A-50-36209 and JP-A-53-8128,
No. 3-36223, No. 54-74728, No. 60-3
No. 626, No. 61-143748, No. 61-1516
Nos. 44 and 63-58440, and combinations of trihalomethyl compounds and salt-forming organic dyes. Such trihalomethyl compounds include oxazole-based compounds and triazine-based compounds, both of which have excellent stability over time and give clear print-out images.

As the colorant for the image, other dyes can be used in addition to the above-mentioned salt-forming organic dyes. Suitable dyes, including salt-forming organic dyes, include oil-soluble dyes and basic dyes. Specifically, Oil Yellow # 101, Oil Yellow # 103, Oil Pink #
312, oil green BG, oil blue BOS, oil blue # 603, oil black BY, oil black BS, oil black T-505 (all manufactured by Orient Chemical Industry Co., Ltd.), Victoria Pure Blue, crystal violet (CI42555), methyl Violet (CI42535), ethyl violet, rhodamine B (CI145170B), malachite green (CI42000), methylene blue (CI5201)
5) and the like. Also, Japanese Patent Application Laid-Open No.
The dyes described in JP 93247 A are particularly preferred. These dyes are used in an amount of 0.1 to the total solid content of the printing plate material.
It can be added to the printing plate material in a proportion of from 01 to 10% by weight, preferably from 0.1 to 3% by weight. Further, a plasticizer is added to the printing plate material of the present invention, if necessary, in order to impart flexibility and the like to the coating film. For example, butylphthalyl, polyethylene glycol, tributyl citrate, diethyl phthalate, dibutyl phthalate, dihexyl phthalate, dioctyl phthalate, tricresyl phosphate, tributyl phosphate, trioctyl phosphate, tetrahydrofurfuryl oleate, acrylic acid or methacrylic acid Oligomers and polymers are used.

The recording layer of the lithographic printing plate precursor according to the invention can be usually produced by dissolving each of the above-mentioned components in a solvent and coating the solution on a suitable support. As the solvent used here, 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,
Dimethoxyethane, methyl lactate, ethyl lactate, N, N-
Dimethylacetamide, N, N-dimethylformamide, tetramethylurea, N-methylpyrrolidone, dimethylsulfoxide, sulfolane, γ-butyrolactone,
Examples include, but are not limited to, toluene. These solvents are used alone or as a mixture. The concentration of the above components (total solids including additives) in the solvent is preferably 1 to 50% by weight. Also apply,
The coating amount (solid content) on the support obtained after drying varies depending on the intended use, but generally, the lithographic printing plate precursor is preferably from 0.5 to 5.0 g / m ² .

Various methods can be used for the coating, such as bar coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating, roll coating and the like. Can be. As the coating amount decreases, the apparent sensitivity increases, but the film characteristics of the photosensitive film deteriorate. In the photosensitive layer according to the invention, a surfactant for improving coating properties, for example, a fluorine-based surfactant described in JP-A-62-170950 can be added. A preferable addition amount is 0.01 to the total solid content of the recording layer.
To 1% by weight, more preferably 0.05 to 0.5% by weight
It is.

The structure of the recording layer of the lithographic printing plate precursor according to the invention may be a single layer or a multilayer structure. That is,
The recording layer formed on the support is only one positive recording layer according to the present invention containing the above-mentioned (A) a water-insoluble and alkali-soluble resin, (B) an infrared absorber and (C) an organic quaternary ammonium salt. Or a recording layer composed of two or more layers laminated with another layer. The layer configuration of the recording layer is arbitrary. For example, recording is performed by laminating two or more positive recording layers containing (A) a water-insoluble and alkali-soluble resin, (B) an infrared absorber, and (C) an organic quaternary ammonium salt. Layer, a recording layer obtained by laminating a positive recording layer according to the present invention and another known recording layer, or the layer itself is not sensitive to an infrared laser and does not contain an infrared absorber (A) water-insoluble and alkali-soluble It may be a recording layer laminated with a layer mainly composed of a resin. In the recording layer having a plurality of layer configurations, the positive recording layer according to the present invention has the property that the positive recording layer according to the present invention can achieve a good development latitude in any case. Preferably, the layer is the uppermost layer in the recording layer. When the recording layer has a multilayer structure, the coating amount of each layer is
Although it can be appropriately selected according to the desired characteristics, in general, for example, when a two-layer structure is adopted, the coating amount of the upper layer is in the range of 0.05 to 5 g / cm ² , and the coating amount of the lower layer is 0.1 g / cm ² . 5
It is preferably in the range of 5 to 5 g / cm ² .

In the present invention, (C) the organic quaternary ammonium salt functions as (A) an inhibitor for dissolving an alkali-soluble resin in a water-insoluble and alkali-soluble resin. (C) It is also a preferable embodiment to have a concentration gradient such that the organic quaternary ammonium salt is contained in a large amount and is small in a deep portion. As means for realizing such a configuration, for example, two or more positive recording layers according to the present invention are arranged, and an upper layer contains a large amount of (C) an organic quaternary ammonium salt as a dissolution inhibitor, It is also possible to take measures to reduce the amount of the organic quaternary ammonium salt (C) contained in the lower recording layer. Further, even when the positive recording layer according to the present invention is provided on a general positive recording layer or (A) a layer having no infrared sensitivity which is mainly composed of a water-insoluble and alkali-soluble resin, Since the recording layer functions as a layer for suppressing the penetration of the alkali developing solution in the unexposed area, good latitude, which is the effect of the present invention, can be realized even if any recording layer is provided below.

[Support] The support used in the present invention is a dimensionally stable plate, for example, paper or paper laminated with plastic (eg, polyethylene, polypropylene, polystyrene, etc.). , Metal plates (eg, aluminum, zinc, copper, etc.), plastic films (eg, cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, Polycarbonate, polyvinyl acetal, etc.), paper as described above, or paper on which metal is laminated, or a plastic film. As the support of the present invention, a polyester film or an aluminum plate is preferable, and among them, an aluminum plate having good dimensional stability and relatively low cost is particularly preferable. Suitable aluminum plates are a pure aluminum plate and an alloy plate containing aluminum as a main component and a trace amount of a different element, and may be a plastic film on which aluminum is laminated or vapor-deposited. The foreign elements contained in the aluminum alloy include:
Silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel, titanium and the like. The content of the foreign element in the alloy is at most 10% by weight or less. Particularly preferred aluminum in the present invention is pure aluminum. However, completely pure aluminum is difficult to produce due to refining technology, and therefore may contain a slightly different element.
As described above, the composition of the aluminum plate applied to the present invention is not specified, and an aluminum plate of a conventionally known and used material can be appropriately used. The thickness of the aluminum plate used in the present invention is about 0.1
mm to 0.6 mm, preferably 0.15 mm to 0.1 mm.
4 mm, particularly preferably 0.2 mm to 0.3 mm.

Prior to roughening the aluminum plate, if necessary, a degreasing treatment with, for example, a surfactant, an organic solvent or an alkaline aqueous solution is performed to remove rolling oil on the surface. The surface roughening treatment of the aluminum plate
The method is performed by various methods, for example, a method of mechanically roughening the surface, a method of electrochemically dissolving and roughening the surface, and a method of chemically selectively dissolving the surface. Known mechanical methods such as a ball polishing method, a brush polishing method, a blast polishing method, and a buff polishing method can be used as the mechanical method. In addition, as an electrochemical surface roughening method, there is a method of performing an alternating or direct current in a hydrochloric acid or nitric acid electrolyte.
Further, as disclosed in JP-A-54-63902, a method in which both are combined can be used. The aluminum plate thus surface-roughened is subjected to an alkali etching treatment and a neutralization treatment as required, and then subjected to an anodic oxidation treatment, if desired, in order to increase the water retention and abrasion resistance of the surface. As the electrolyte used for the anodic oxidation treatment of the aluminum plate, various electrolytes that form a porous oxide film can be used. Generally, sulfuric acid, phosphoric 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 the electrolyte.

The anodizing treatment conditions vary depending on the electrolyte used and cannot be specified unconditionally. However, in general, the concentration of the electrolyte is 1 to 80% by weight, the solution temperature is 5 to 70 ° C., and the current density is 5 to 60 A. / Dm ² , a voltage of 1 to 100 V, and an electrolysis time of 10 seconds to 5 minutes are appropriate. When the amount of the anodic oxide film is less than 1.0 g / m ² , the printing durability is insufficient or the non-image portion of the lithographic printing plate is easily scratched,
So-called "scratch stains" in which ink adheres to scratches during printing are likely to occur. After the anodizing treatment, the aluminum surface is subjected to a hydrophilic treatment as necessary. U.S. Pat. Nos. 2,7,7
No. 14,066, No. 3,181,461, No. 3,2
There is an alkali metal silicate (e.g., sodium silicate aqueous solution) method as disclosed in U.S. Pat. Nos. 80,734 and 3,902,734. In this method, the support is immersed or electrolytically treated with an aqueous solution of sodium silicate. Further, potassium fluoride zirconate disclosed in JP-B-36-22063 and U.S. Pat. Nos. 3,276,868, 4,153,461 and 4,689,272 are disclosed. A method of treating with polyvinyl phosphonic acid as described above is used.

The lithographic printing plate precursor according to the invention has a positive recording layer provided on a support. An undercoat layer may be provided between the positive and negative recording layers if necessary. As the undercoat layer component, various organic compounds are used, for example, carboxymethyl cellulose, dextrin, gum arabic, phosphonic acids having an amino group such as 2-aminoethylphosphonic acid, and phenylphosphonic acid optionally having a substituent , Organic phosphonic acids such as naphthylphosphonic acid, alkylphosphonic acid, glycerophosphonic acid, methylenediphosphonic acid and ethylenediphosphonic acid, phenylphosphoric acid which may have a substituent, naphthylphosphoric acid, alkylphosphoric acid and glycerophosphoric acid Organic phosphoric acid, optionally substituted phenylphosphinic acid, naphthylphosphinic acid, organic phosphinic acid such as alkylphosphinic acid and glycerophosphinic acid, amino acids such as glycine and β-alanine, and hydrochloric acid of triethanolamine Has hydroxy groups such as salts -Alanine, and hydrochlorides of amines that may be used in combination of two or more.

This organic undercoat layer can be provided by the following method. That is, water or methanol, ethanol,
A method in which a solution obtained by dissolving the above organic compound in an organic solvent such as methyl ethyl ketone or a mixed solvent thereof is applied to an aluminum plate and dried, and an organic solvent such as water or methanol, ethanol, methyl ethyl ketone or a mixed solvent thereof is used. In this method, an aluminum plate is immersed in a solution in which the above-mentioned organic compound is dissolved to adsorb the above-mentioned compound, and then washed with water or the like and dried to form an organic undercoat layer. In the former method, a solution of the above organic compound having a concentration of 0.005 to 10% by weight can be applied by various methods. In the latter method, the concentration of the solution is 0.01 to 20% by weight, preferably 0.05 to 5% by weight.
The immersion temperature is 20 to 90 ° C., preferably 25 to 5 ° C.
0 ° C., and the immersion time is 0.1 second to 20 minutes, preferably 2 seconds to 1 minute. The solution used for this is ammonia,
The pH can be adjusted to a range of 1 to 12 with a basic substance such as triethylamine or potassium hydroxide or an acidic substance such as hydrochloric acid or phosphoric acid. Further, a yellow dye can be added for improving the tone reproducibility of the image recording material. The coating amount of the organic undercoat layer is suitably from ² to 200 mg / m ² , and preferably from 5 to 100 mg / m ² . If the coating amount is less than 2 mg / m ² , sufficient printing durability cannot be obtained. The same is true even if it is larger than 200 mg / m ² .

The positive planographic printing plate precursor prepared as described above is usually subjected to image exposure and development processing. Examples of the light source of the actinic ray used for the image exposure include a mercury lamp, a metal halide lamp, a xenon lamp, a chemical lamp, a carbon arc lamp, and the like. As radiation,
There are electron beams, X-rays, ion beams, far infrared rays, and the like. In addition, g-line, i-line, Deep-UV light, and high-density energy beam (laser beam) are also used. Laser beams include helium / neon laser, argon laser, krypton laser, helium / cadmium laser, K
rF excimer laser and the like can be mentioned. In the present invention, a light source having an emission wavelength in the near infrared to infrared region is preferable, and a solid-state laser and a semiconductor laser are particularly preferable.

As a developer and a replenisher used for developing the image forming material of the present invention, conventionally known aqueous alkali solutions can be used. These include, using an alkali silicate, containing silicon dioxide, a so-called "silicate developer", a non-reducing sugar, and a base, and a "non-silicate developer" substantially free of silicon dioxide. is there.
Here, “substantially” means that the presence of trace amounts of silicon dioxide as unavoidable impurities and by-products is allowed. As the alkaline aqueous solution, pH 12.5
~ 13.5 are preferred. In the developing step of the image forming material of the present invention, any of the above-mentioned developing solutions can be applied, but from the viewpoint of improving the developing latitude, it is preferable to use a non-silicate developing solution. It is considered that the action on the photosensitive layer is different between a “non-silicate developer” containing a base and an organic compound having a buffering action as a main component and a “silicate developer” containing an inorganic compound as a main component. The mechanism for exhibiting excellent effects when the lithographic printing plate precursor according to the invention is particularly non-silicate developed will be described below. In the heat-sensitive layer of the lithographic printing plate precursor according to the invention, in the unexposed area, the alkali-soluble resin and the organic quaternary ammonium salt constituting the heat-sensitive layer and the salt of the organic compound in the developer mainly interact with each other such as hydrogen bonds. By forming the action, a stronger dissolution inhibiting effect is exhibited for the developing solution, and an alkali resistance improving effect is also exhibited for a highly active developing solution. Similarly, damage due to scratches formed on the surface can be prevented by the development suppressing effect. On the other hand, in the exposed part, the above-mentioned interaction is hardly developed, and even if it is, the dissolution suppressing effect is small and the exposed part shows sufficient solubility in the developer. Furthermore, the effect of the organic compound salt described above is that, in the case of a heat-sensitive layer corresponding to an infrared laser, the dissolution suppressing effect is not sufficiently released due to heat diffusion to the support in a portion of the exposed portion close to the support, and Since the property is lower than that near the surface, it is more remarkably exhibited especially when the concentration of the alkali-soluble resin and the organic quaternary ammonium salt compound is increased near the surface of the heat-sensitive layer.

The details of the developer usable in the present invention are described below. First, the “silicate developer” will be described. The alkali silicate exhibits alkalinity when dissolved in water, and examples thereof include alkali metal silicates such as sodium silicate, potassium silicate, and lithium silicate, and ammonium silicate. The alkali silicate may be used alone or in combination of two or more. The aqueous alkaline solution contains silicon oxide SiO _{2 as} a component of silicate and alkali oxide M ₂ O.
(M represents an alkali metal or ammonium group.) By adjusting the mixing ratio and concentration, the developability can be easily adjusted. An alkali metal silicate as described in JP-A-7427 is effectively used. Among the alkaline aqueous solutions, those having a mixing ratio (SiO ₂ / M ₂ O: molar ratio) of the silicon oxide SiO ₂ and the alkali oxide M ₂ O of 0.5 to 3.0 are preferable, and 1.0 to 1.0. 2.
0 is more preferred. When the SiO ₂ / M ₂ O is 0.
If it is less than 5, the alkali strength increases,
When a general-purpose aluminum plate or the like is etched as a support for a lithographic printing plate precursor, a problem may occur, and when it exceeds 3.0, developability may be reduced.

The concentration of the alkali silicate in the developer is 1 to 10% by weight based on the weight of the aqueous alkali solution.
Is preferably 3 to 8% by weight, and most preferably 4 to 7% by weight. If the concentration is less than 1% by weight, the developability and processing capacity may be reduced. And the treatment of waste liquid may be hindered.

Next, the “non-silicate developer” will be described. As described above, this developer is composed of a non-reducing sugar and a base, and the non-reducing sugar has no reducing property because it has no free aldehyde group or ketone group. It means a saccharide, and is classified into a trehalose-type oligosaccharide in which reducing groups are bonded to each other, a glycoside in which a reducing group of a saccharide is bonded to a non-saccharide, and a sugar alcohol reduced by hydrogenating a saccharide. In the present invention, any of these can be suitably used.

The trehalose-type oligosaccharides include, for example, saccharose and trehalose, and the glycosides include, for example, alkyl glycosides, phenol glycosides, and mustard oil glycosides. Examples of the sugar alcohol include D, L-arabit, ribit, xylit, D, L-sorbit, D, L-annit,
D, L-idit, D, L-talit, zuricit, allozurcit and the like. Further, maltitol obtained by hydrogenation of a disaccharide, a reductant (reduced starch syrup) obtained by hydrogenation of an oligosaccharide, and the like can also be preferably mentioned.

Among the non-reducing sugars, sugar alcohols and saccharose are preferable, and D-sorbitol, saccharose, and reduced starch syrup are more preferable, since they have a buffering action in an appropriate pH range. These non-reducing sugars may be used alone or in combination of two or more, and the ratio in the developer is preferably 0.1 to 30% by weight,
1-20% by weight is more preferred.

The alkali silicate or non-reducing sugar can be appropriately combined with an alkali agent as a base from conventionally known ones. Examples of the alkaline agent include sodium hydroxide, potassium hydroxide,
Lithium hydroxide, trisodium phosphate, tripotassium phosphate, triammonium phosphate, disodium phosphate, dipotassium phosphate, diammonium phosphate, sodium carbonate, potassium carbonate, ammonium carbonate, sodium bicarbonate, potassium bicarbonate And inorganic alkali agents such as ammonium bicarbonate, sodium borate, potassium borate and ammonium borate, potassium citrate, tripotassium citrate, sodium citrate and the like. In addition, monomethylamine, dimethylamine, trimethylamine,
Monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine,
Organic alkali agents such as triisopropylamine, n-butylamine, monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanol amici, ethyleneimine, ethylenediamine, and pyridine can also be suitably mentioned. These alkaline agents may be used alone or in combination of two or more.

Of these, sodium hydroxide and potassium hydroxide are preferred. The reason is that adjusting the amount of addition to the non-reducing sugar enables pH adjustment in a wide pH range. Also, trisodium phosphate,
Tripotassium phosphate, sodium carbonate, potassium carbonate, and the like are also preferable because they themselves have a buffering action.

Further, when developing using an automatic developing machine, an aqueous solution (replenisher) having a higher alkali strength than the developing solution is used.
It is known that a large amount of a lithographic printing plate can be processed without replacing the developing solution in the developing tank for a long time by adding the lithographic printing plate to the developing solution. This replenishment system is also preferably applied in the present invention. Various surfactants and organic solvents can be added to the developing solution and the replenishing solution as needed for the purpose of accelerating or suppressing the developing property, dispersing the developing residue and improving the ink affinity of the printing plate image area. Preferred surfactants include anionic, cationic, nonionic and amphoteric surfactants. Further, the developing solution and the replenisher may contain, if necessary, a reducing agent such as a sodium salt or a potassium salt of an inorganic acid such as hydroquinone, resorcinol, sulfurous acid, and bisulfite, and further include an organic carboxylic acid, an antifoaming agent, and a water softener. Can be added. The printing plate developed using the above developer and replenisher is post-treated with washing water, a rinsing solution containing a surfactant and the like, and a desensitizing solution containing gum arabic and a starch derivative. As a post-process when the image recording material of the present invention is used as a printing plate, these processes can be used in various combinations.

In recent years, in the plate making and printing industry, automatic developing machines for printing plates have been widely used in order to rationalize and standardize plate making operations. This automatic developing machine generally includes a developing section and a post-processing section, and includes a device for transporting a printing plate, each processing solution tank and a spray device, and transports the exposed printing plate horizontally while pumping each plate. The developing process is performed by spraying a processing liquid from a spray nozzle. Recently, a method has been known in which a printing plate is immersed and conveyed by a submerged guide roll or the like in a processing liquid tank filled with a processing liquid to perform processing. In such an automatic processing, the processing can be performed while replenishing each processing liquid with a replenisher according to the processing amount, the operating time, and the like. Further, a so-called disposable processing method in which processing is performed with a substantially unused processing liquid can also be applied.

In the lithographic printing plate precursor according to the present invention, image portions unnecessary for the lithographic printing plate obtained by image exposure, development, washing and / or rinsing and / or gumming (for example, the film of the original film) If there is an edge trace), the unnecessary image portion is erased. Such erasing is preferably carried out by applying an erasing liquid as described in, for example, Japanese Patent Publication No. 2-129393 to an unnecessary image portion, leaving it for a predetermined time, and then washing it with water. A method described in JP-A-59-174842, in which active light guided by an optical fiber is applied to an unnecessary image portion and then developed, can be used.

The lithographic printing plate obtained as described above can be subjected to a printing step after applying a desensitized gum if desired. Is subjected to a burning process. When burning a lithographic printing plate, before burning,
No. 2518, No. 55-28062, JP-A-62-3
It is preferable to treat with a surface-regulating liquid as described in JP-A Nos. 1859 and 61-159655. As a method, a sponge or absorbent cotton impregnated with the surface conditioning liquid is applied on a lithographic printing plate, or a method in which the printing plate is immersed in a vat filled with the surface conditioning solution and applied, Application by an automatic coater or the like is applied. Further, it is more preferable to make the application amount uniform with a squeegee or a squeegee roller after the application.

The coating amount of the surface conditioning liquid is generally 0.03 to 0.8.
g / m ² (dry weight) is appropriate. The lithographic printing plate to which the surface conditioning liquid has been applied is dried if necessary, and then burned (for example, a burning processor sold by Fuji Photo Film Co., Ltd .: "BP-130").
0 "). The heating temperature and time in this case depend on the type of the component forming the image,
The temperature is preferably in the range of 180 to 300 ° C. for 1 to 20 minutes.

The burned lithographic printing plate can be subjected to conventional treatments such as washing with water and gumming if necessary. When is used, so-called desensitizing treatment such as gumming can be omitted. The lithographic printing plate obtained by such a process is set on an offset printing machine or the like and used for printing a large number of sheets.

[0080]

(Undercoat liquid)

 ・ 0.3g of the following compound ・ 100g of methanol ・ 1g of water

[0081]

Embedded image

(Example 1) The following photosensitive solution 1 was applied to the obtained substrate so that the coating amount became 1.0 g / m ² ,
TABAI's PERFECT OVEN PH20
At 0, WindControl was set to 7, and drying was performed at 140 ° C. for 50 seconds to obtain a lithographic printing plate precursor 1.

[Photosensitive solution 1] Ammonium salt (1) 0.04 g m, p-cresol novolak (m / p ratio = 6/4, weight average molecular weight 3,500, unreacted cresol 0.5% by weight) 0.474 g Specific copolymer 1 described in JP-A-11-288093 1. 2.37 g Cyanine dye A (the following structure) 0.155 g 2-methoxy-4- (N-phenylamino) benzene diazonium hexafluorophosphate 0.03 g Tetrahydroanhydride phthalate Acid 0.19 g Ethyl violet counter ion converted to 6-hydroxy-β-naphthalenesulfonic acid 0.05 g Fluorosurfactant (MegaFac F176PF, manufactured by Dainippon Ink and Chemicals, Inc.) 0.035 g Fluorosurfactant Surfactant (MegaFac MCF-312, manufactured by Dainippon Ink and Chemicals, Inc.) ) 0.05 g paratoluenesulfonic acid 0.008 g bis-p-hydroxyphenylsulfone 0.063 g dodecyl stearate 0.06 g γ-butyllactone 13 g methyl ethyl ketone 24 g 1-methoxy-2-propanol 11 g

[0084]

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Example 2 The following photosensitive solution 2 was applied to the obtained substrate so that the coating amount was 1.6 g / m ² ,
Drying was performed under the same conditions as in Example 1 to obtain a lithographic printing plate precursor 2. [Photosensitive solution 2] Ammonium salt (1) 0.025 g m, p-cresol novolak (m / p ratio = 6/4, weight average molecular weight 5000, containing unreacted cresol 0.5% by weight) 2.25 g cyanine dye A 0.105 g 2-methoxy-4- (N-phenylamino) benzene diazonium hexafluorophosphate 0.03 g Tetrahydrophthalic anhydride 0.10 g A counter ion of ethyl violet converted to 6-hydroxy-β-naphthalenesulfonic acid 0 0.063 g Fluorosurfactant (Megafac F176PF, manufactured by Dainippon Ink and Chemicals, Inc.) 0.035 g Fluorosurfactant (Megafac MCF-312, manufactured by Dainippon Ink and Chemicals, Inc.) 0.13 g Bis-p-hydroxyphenyl sulfone 0.08 g methyl ethyl ketone 6 g 1-methoxy-2-propanol 10g

(Example 3) The following photosensitive solution 3-A was applied to the support used in Example 1 and the coated amount after drying was 0.85 g / m2.
After applying so that it becomes ² , PEBECT manufactured by Tabai
It was dried at 140 ° C. for 50 seconds with WindControl set to 7 using OVEN PH200. Subsequently, the photosensitive solution 3 was adjusted so that the coating amount after drying was 0.15 g / m ^2.
B, and applied to Tabi's PERFECT OVEN P
Set WindControl to 7 in H200 and set 1
After drying at 20 ° C. for 60 seconds, a lithographic printing plate precursor 3 was obtained. [Photosensitive solution 3-A] m, p-cresol novolak (m / p ratio = 6/4, weight average molecular weight 5000, containing unreacted cresol 0.5% by weight) 0.237 g Specific solution described in JP-A-11-288093 Copolymer 2.37 g Cyanine dye A 0.10 g 2-methoxy-4- (N-phenylamino) benzene diazonium hexafluorophosphate 0.01 g Tetrahydrophthalic anhydride 0.19 g The counter ion of ethyl violet was 6-hydroxy- Compound converted to β-naphthalenesulfonic acid 0.05 g Fluorosurfactant (MegaFac F-176PF, manufactured by Dainippon Ink and Chemicals, Inc.) 0.035 g Fluorosurfactant (MegaFac MCF-312, Dainippon Japan) Ink Chemical Industry Co., Ltd.) 0.05 g p-toluenesulfonic acid 0.008 g -p- hydroxyphenyl sulfone 0.06 g .gamma.-butyrolactone 13g methyl ethyl ketone 24 g 1-methoxy-2-propanol 11g

[Photosensitive solution 3-B] Ammonium salt (1) 0.1 gm, p-cresol novolak (m / p ratio = 6/4, weight average molecular weight 5000, unreacted cresol 0.5% by weight) 0 .237 g Cyanine dye A 0.025 g 2-methoxy-4- (N-phenylamino) benzene diazonium hexafluorophosphate 0.01 g Fluorosurfactant (MegaFac F-176PF, manufactured by Dainippon Ink and Chemicals, Inc.) 0.035 g Fluorosurfactant (Megafac MCF-312, manufactured by Dainippon Ink and Chemicals, Inc.) 0.05 g Bis-p-hydroxyphenylsulfone 0.003 g Dodecyl stearate 0.03 g Methyl ethyl ketone 15 g 1-methoxy -2-propanol 8g

Example 4 The above photosensitive solution 3-A was applied to the support used in Example 1 after drying, and the coated amount was 0.85 g / m ^2.
After applying so that it becomes
7 WindControl at OVEN PH200
And dried at 140 ° C. for 50 seconds. Subsequently, the following photosensitive solution 4 was applied so that the application amount after drying was 0.15 g / m ^2, and PERECT OVEN P manufactured by Tabai Co.
Set WindControl to 7 in H200 and set 1
After drying at 20 ° C. for 60 seconds, a lithographic printing plate precursor 4 was obtained. [Photosensitive solution 4] Ammonium salt (1) 0.035 g m, p-cresol novolak (m / p ratio = 6/4, weight average molecular weight 5000, containing unreacted cresol 0.5% by weight) 0.237 g cyanine dye A 0.025 g 2-methoxy-4- (N-phenylamino) benzene diazonium hexafluorophosphate 0.01 g Fluorinated surfactant (MegaFac F-176PF, manufactured by Dainippon Ink and Chemicals, Inc.) 0.035 g Fluorine Surfactant (Megafac MCF-312, manufactured by Dainippon Ink and Chemicals, Inc.) 0.05 g Bis-p-hydroxyphenylsulfone 0.003 g Dodecyl stearate 0.03 g Methyl ethyl ketone 15 g 1-methoxy-2-propanol 8 g

(Example 5) The photosensitive solution 3-A was applied to the support used in Example 1 after drying, and the coated amount was 0.85 g / m ^2.
After applying so that it becomes
7 WindControl at OVEN PH200
And dried at 140 ° C. for 50 seconds. Subsequently, the following photosensitive solution 5 was applied so that the coating amount after drying was 0.15 g / m ^2, and PERFECT OVEN P manufactured by Tabai Co., Ltd.
Set WindControl to 7 in H200 and set 1
After drying at 20 ° C. for 60 seconds, a lithographic printing plate precursor 5 was obtained. [Photosensitive solution 5] Ammonium salt (2) 0.017 g m, p-cresol novolak (m / p ratio = 6/4, weight average molecular weight 5000, containing unreacted cresol 0.5% by weight) 0.237 g cyanine dye A 0.025 g 2-methoxy-4- (N-phenylamino) benzene diazonium hexafluorophosphate 0.01 g Fluorinated surfactant (MegaFac F-176PF, manufactured by Dainippon Ink and Chemicals, Inc.) 0.035 g Fluorine Surfactant (Megafac MCF-312, manufactured by Dainippon Ink and Chemicals, Inc.) 0.05 g Bis-p-hydroxyphenylsulfone 0.003 g Dodecyl stearate 0.03 g Methyl ethyl ketone 15 g 1-methoxy-2-propanol 8 g

(Examples 6 to 14) In the photosensitive solution 4 of Example 4, the following Table 1 was used in place of the ammonium salt (1).
Lithographic printing plate precursor 4 except that the ammonium salt shown in
The lithographic printing plate precursors 6 to 14 were prepared in the same procedure as in the preparation of the lithographic printing plate precursors.

[0091]

[Table 1]

(Examples 15 to 17) The same procedure as in the preparation of the lithographic printing plate precursor 4 except that the ammonium salt shown in Table 2 below was used in place of the ammonium salt (1) in the photosensitive solution 1 of Example 1 described above. By the procedure, planographic printing plate precursors 15 to 17 were prepared.

[0093]

[Table 2]

Comparative Example 1 A lithographic printing plate precursor 18 was obtained in the same manner as in Example 1 except that the ammonium salt (1) was not added to the photosensitive solution 1 of Example 1.

Comparative Example 2 A lithographic printing plate precursor 19 was obtained in the same manner as in Example 2 except that the ammonium salt (1) was not added to the photosensitive solution 2 of Example 2.

Comparative Example 3 A lithographic printing plate precursor 20 was obtained in the same manner as in Example 3 except that the ammonium salt (1) was not added to the photosensitive solution 3-B of Example 3.

[Evaluation of lithographic printing plate precursors] [Scratch resistance test (1)] The obtained lithographic printing plate precursors 1 to 14 of the present invention and lithographic printing plate precursors 15 to 17 of comparative examples were obtained.
To Rotary Ablation Tester (TOYOS
EIKI Co., Ltd.), and rubbed 30 times with Abrazelfelt CS5 under a load of 250 g. Thereafter, a developer DT-1 or DP-4 manufactured by Fuji Photo Film Co., Ltd.
(Diluted in tap water at 1: 8) was charged into a PS processor 900H manufactured by Fuji Photo Film and developed at a liquid temperature of 30 ° C. for a developing time of 12 seconds. FP-2 was used as a gum solution.
W (1: 1 diluted with tap water) was used. In addition,
The developer DT-1 is a so-called non-silicate developer, DP
-4 is a silicate-containing developer.

The scratch resistance was evaluated according to the following criteria. The results are shown in Table 3 below. In general, those having no problem in scratch resistance under these conditions can be said to satisfy practical performance. ：: The optical density of the photosensitive film at the rubbed portion did not change as compared with the non-frictional portion. ×: The optical density of the photosensitive film at the rubbed portion was significantly reduced as compared with the non-frictional portion.

[Scratch resistance test (2)] The obtained lithographic printing plate precursor was subjected to a continuous load type scratch strength tester TYPE-HE.
Using IDON-18 (manufactured by Shinto Kagaku Co., Ltd.), R =
Under a condition of a diamond needle of 0.4 mm and a scratching speed of 50 mm / sec, a scratch was made by changing a load. Thereafter, a developer DT-1 or DP-4 manufactured by Fuji Photo Film Co., Ltd.
(Diluted in tap water at 1: 8) was charged into a PS processor 900H manufactured by Fuji Photo Film and developed at a liquid temperature of 30 ° C. for a developing time of 12 seconds. In addition, FP-2W is used as a gum solution.
(1: 1 diluted with tap water) was used. The plate after development is visually evaluated and the maximum weight without scratches (g)
Was defined as the scratch resistance. The results are shown in Table 3 below. Normal,
With a maximum load of 5 g or more, there is no practical problem,
When it is 10 g or more, it can be said that it has extremely excellent scratch resistance and can withstand severe handling.

[Development latitude evaluation (1)] The lithographic printing plate precursors 1 to 17 of the present invention and the lithographic printing plate precursors 18 to 20 of the comparative examples were prepared by Trendsette manufactured by Creo Corporation.
At r, a test pattern was drawn in the form of an image with an infrared laser at a beam intensity of 9 w and a drum rotation speed of 150 rpm. Then, a developer DT- manufactured by Fuji Photo Film Co., Ltd.
1 or DP-4 (diluted with tap water 1: 8) was charged into a PS processor 900H manufactured by Fuji Photo Film Co., Ltd., and developed at a liquid temperature of 30 ° C. and a developing time of 12 seconds. FP-2W (1: 1 diluted with tap water) as a gum solution
It was used. Under these developing conditions, the developability of the exposed portions was good for all lithographic plates. Next, assuming that the developing solution was concentrated, the dilution of the developing solution was changed to (diluted with tap water 1: 7), and the lithographic plate was similarly exposed at a solution temperature of 30 ° C. and a developing time of 12 seconds. The printing plate was developed. Usually, those having no problem in developability under these conditions can be said to satisfy practical performance. In the lithographic printing plate after development, the image density of the concentrated developer was determined by visually evaluating the decrease in the optical density of the unexposed area of the recording layer according to the following criteria. The results are shown in Table 3 below. It should be noted that the case where no concentration decrease was observed indicates that the image portion was not eluted with respect to the developer having higher activity, and it can be said that the latitude with respect to the activity of the developer is wide. ：: No decrease in concentration was observed ×: A decrease in concentration was observed

[0101]

[Table 3]

As is evident from Table 3, the lithographic printing plate precursor according to the present invention has excellent scratch resistance as compared with the comparative example, and the density of the image area decreases even when a high-concentration developer is used. No development was observed, indicating good development latitude.

[Development latitude evaluation (2)] Next, the same evaluation was performed under the more severe conditions where the developer was concentrated. The resulting lithographic printing plate precursors 1 to 14 of the present invention and the lithographic printing plate precursors 15 to 17 of the comparative examples were prepared using Tr
A test pattern was drawn in an image shape with an infrared laser at an end setter at a beam intensity of 9 w and a drum rotation speed of 150 rpm. Next, Fuji Photo Film Co., Ltd.
Developing solution DT-1 or DP-4 (diluted in tap water at 1: 6) with Fuji Photo Film PS processor 9
The solution was charged in 00H and developed at a liquid temperature of 30 ° C. and a developing time of 12 seconds. In the same manner as described above, the image forming property in a higher-density developer was determined based on the following criteria by visually evaluating the decrease in the optical density of the unexposed portion of the recording layer in the lithographic printing plate after development. The results are shown in Table 4 below. Table 4 also shows the results of the development latitude evaluation (1). It should be noted that the case where no concentration decrease was observed indicates that the image portion was not eluted with respect to the developing solution having higher activity, and it can be said that the latitude with respect to the activity of the developing solution is extremely wide. ：: No decrease in density was observed. Δ: A slight decrease in density that could be visually detected was observed. X: A clear decrease in density was observed.

[0104]

[Table 4]

As is clear from Tables 4 and 3, the planographic printing plate precursor according to the present invention has remarkable effects on both scratch resistance and development latitude, especially when development is performed using a non-silicate developer. I understand. From these results, it can be seen that among the lithographic printing plate precursors of the present invention, those using an organic quaternary ammonium salt having an aryl group and a carbonyl group for the recording layer, a recording layer having a multilayer structure, and an organic It was confirmed that those containing a large amount of secondary ammonium salts were particularly excellent in effect.

[0106]

According to the present invention, it is possible to provide a positive lithographic printing plate precursor for an infrared laser for direct plate making, which has excellent latitude during image formation by development and excellent scratch resistance.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Akio Oda 4,000 Kawajiri, Yoshida-cho, Haibara-gun, Shizuoka Prefecture Inside Fujisha Shin Film Co., Ltd. Incorporated F term (reference) 2H025 AA04 AA13 AB03 AC08 AD03 BG00 CB28 CB41 CB45 CB52 CC11 CC20 2H096 AA06 BA11 EA04 EA23 GA08

Claims (2)

[Claims] 1. A support comprising (A) a water-insoluble and alkali-soluble resin, (B) an infrared absorber and (C) an organic quaternary ammonium salt, and having a solubility in an alkaline aqueous solution by exposure to an infrared laser. A positive-working lithographic printing plate precursor provided with an increasing positive-working recording layer. 2. The (C) organic quaternary ammonium salt comprises:
2. The compound having at least one group selected from an aryl group and a carbonyl group in a molecule.
The positive type lithographic printing plate precursor described in 1.