JPH046938B2 - - Google Patents

Description

[Detailed description of the invention]

[Field of Application of the Invention] The present invention relates to a silver salt offset printing plate, and more particularly to a material for laser plate making that has excellent properties against laser light in an offset printing plate to which a silver salt diffusion transfer method is applied. . Recent advances in photolithography technology have been remarkable.
Currently, printing operations are becoming faster and more streamlined. One of these is plate-making technology that uses laser light. Laser plate-making uses the coherent light of laser light to produce high-energy density and
This is a plate-making method that uses the property of modulation to directly obtain a printing plate from a manuscript or block copy. That is, it has three functions: a facsimile machine, an exposure machine, and a plate-making camera. Laser plate making is attracting attention as a technology that will see significant application and development in the future, as it satisfies the industry's needs for resource conservation, pollution-free production, and lower plate-making costs. Currently, the most widely used laser beams include helium-neon, helium-cadmium, argon, krypton, carbon dioxide, ruby, etc. as the laser oscillation medium, and recently semiconductor lasers have also appeared. LEDs (light emitting diodes) similar to this are also being used. Among these oscillation systems, those most compatible with lithographic printing materials are helium-neon and argon gas lasers, which are currently an innovation in the industry. [Prior Art] Many methods have been known for making lithographic printing plates using the silver salt diffusion transfer method, and a representative example is a plate in which a photosensitive element and a printing image element are integrated. The methods described in Publications No. 42453 and No. 48-30562 are known. These lithographic printing plates produced by the silver salt diffusion transfer method are usually photographed and developed in a roll using a paper or film base as a support to obtain a printing plate. However, when photographing with camera work using such an optical system, the image quality inevitably deteriorates due to the characteristics of the lens or the scattering of light on the printing plate, and as a result, the image resolution of printed matter is reduced. It was the current situation. Under these circumstances, direct plate making technology using laser light was developed, and by directly exposing and writing on the plate without passing through a lens system, it became possible to improve and improve image resolution compared to conventional methods. Summer. Furthermore, it is now possible to store the information read from the manuscript, making it easier to make corrections, layouts, etc., and the plate-making process is currently experiencing significant technological innovation. With this progress in laser platemaking technology,
Lithographic printing materials applied to the silver salt diffusion transfer method are not always satisfactory; for example, image quality deteriorates due to lack of sensitivity and contrast to various laser beams, or long exposure times are required. However, the reality is that laser engraving machines have not yet been fully utilized. [Object of the Invention] The object of the present invention is to provide a lithographic printing material in which a silver image produced by a silver salt diffusion transfer method is ink receptive, and which has characteristics of high sensitivity to argon laser light and high contrast. The second object is to provide a printing material that can produce printed matter without blurring of fine lines or minute halftone dots and without occurrence of scumming. [Specific Structure of the Invention] The object of the present invention described above is to provide a silver salt diffusion transfer comprising a structure in which an antihalation layer and a silver halide emulsion layer are layered and coated from the support side, and a physical development nucleus layer is coated on the upper layer. In the method lithographic printing material, the silver halide composition of the silver halide emulsion layer is at least
This is achieved by containing at least one compound represented by the following general formula [] in the silver halide emulsion, which consists of 98 mol % or more of silver chloride grains. General formula [] (However, A in the formula represents a lower alkyl group having 1 to 4 carbon atoms, and R ¹ and R ² represent the same or different lower alkyl group, hydroxyalkyl group, sulfoalkyl group, or carboxyalkyl group. Y ¹ and Y ² each represents an oxygen atom, Z ¹ and Z ² represent a condensation product of a benzene ring or a naphthalene ring which may have a substituent, X represents an alkali metal atom or an ammonium group, and n represents 0 or 1. ) Next, specific examples of the compound represented by the above general formula will be shown, but the present invention is not limited thereto. The above compounds can be prepared using known methods such as FMHamer.
Author “The Cyanine Dyes and Related
Compounds” (The Cyanine Soy &
1964. Inter-
The method described in Science Publishers,
Alternatively, it can be synthesized according to the methods described in British Patent No. 742112 and US Patent No. 2,213,238. In the method of the present invention, the compound is added to a silver halide emulsion by dissolving it in water or a hydrophilic solvent such as methanol or ethanol. The timing of addition may be arbitrary, but preferably before or after chemical ripening. The amount added is 10 to 500 mg per mole of silver halide.
is sufficient. The present invention will be explained in more detail below. The lithographic printing material for argon laser light of the present invention (hereinafter simply referred to as the printing material of the present invention) has an antihalation layer on a support, a silver halide emulsion layer as a photosensitive layer, and a physical development nucleus on the support. Although the base is a layered structure in which two layers are provided, an intermediate layer may be provided between each of the above layers. In the printing material of the present invention, it is preferable that in the above layer structure, a physical development nucleus layer is provided directly on the photosensitive silver halide emulsion layer. In the present invention, the antihalation layer provided closest to the support is a hydrophilic colloid layer in which, for example, carbon black, dye, or pigment is dispersed. Further, the silver halide composition of the photosensitive silver halide emulsion layer according to the present invention is preferably substantially cubic crystal silver halide containing at least 98 mol % of silver chloride. Such a light-sensitive silver halide emulsion containing silver halide may be a silver chlorobromide or silver chloroiodobromide emulsion containing trace amounts of silver iodide or silver bromide; Preferably, it is a pure silver chloride emulsion containing mol %. Such a silver halide emulsion may be prepared by any method well known in the art, such as a single jet method, a double jet method, or a controlled jet method. As mentioned above, the silver halide emulsion according to the present invention is made up of at least 98 mol% silver chloride grains, so unless the excess halide ion concentration during grain formation is extremely high, it cannot be used in a normal mixing method. Silver halide grains having a cubic crystal shape can be formed by this process. The average grain size of the silver halide in the silver halide emulsion is preferably in the range of about 0.05μ to 2.0μ. After grain formation, soluble salts are removed from this silver halide emulsion by a conventional method. The desalted emulsion can be chemically sensitized using a sulfur sensitizer such as thiosulfate, allylthiocarbamide, thiourea, allyl isothiacyanate, and the like. Furthermore, U.S. Patent No. 2399083, U.S. Patent No. 2597856, U.S. Patent No.
Gold compounds described in US Pat. No. 2597915, etc., US Pat. No. 2448060, US Pat. No. 2540086, US Pat.
The above emulsion can be ripened using noble metal salts such as platinum, palladium, iridium, rhodium, and ruthenium, which are described in Japanese Patent Nos. 2,566,263 and 2,598,079. Gelatin is a hydrophilic binder that can be effectively used in the silver halide emulsion of the present invention.
- Vinyl pyrrolidone, a polyacrylic acid copolymer, a copolymer of methyl vinyl ether and maleic anhydride, or a compound substituted with a cellulose derivative, a gelatin derivative, etc. can be used. Furthermore, various compounds may be added to the emulsion for the purpose of stabilizing it during the manufacturing process or storage, or preventing the occurrence of fog during development. Furthermore, in addition to the above compounds, for example, sensitizers, hardeners, surfactants, etc. can be used as appropriate.
For specific compound examples, see "Product Licensing Index" Volume 92, No. 9232, 107.
~110 pages, ~, ~, X, (1971
(December 2015). The photosensitive silver halide emulsion layer according to the present invention can be formed by coating the emulsion thus prepared as a layer on the antihalation layer by a known method. Next, regarding the development nuclei of the physical development nucleus layer according to the present invention, for example, water-soluble noble metal salts such as gold, silver, platinum, and palladium, or zinc, lead, cadmium, nickel, cobalt, iron, chromium, and tin. , metal colloids obtained by reducing heavy metals such as antimony, bismuth, etc., or water-soluble metal salts thereof, such as nitrates, acetates, borates, chlorides, hydroxides, etc., as water-soluble sulfides, For example, development nuclei obtained by mixing with sulfurized sword or the like can be used. As for the type of hydrophilic binder used in the physical development nucleus layer according to the present invention, the same kind of hydrophilic polymer substances as those used in the photosensitive silver halide emulsion layer described above are applicable, but gelatin, polyvinyl alcohol, etc. Alternatively, a copolymer of methyl vinyl ether and maleic anhydride is preferred, and a combination of these may also be used. The amount of these hydrophilic binders is not necessarily uniform depending on the type of noble metal or binder, but ranges from 30% to 100% by weight relative to the physical development nuclei. The physical development nucleus layer described above is preferably coated directly on the photosensitive silver halide emulsion layer. Examples of the support for the printing material according to the present invention include nitrate film, cellulose acetate film, cellulose acetate butyrate film, polystyrene film, polyethylene phthalate film, polycarbonate film,
Alternatively, there are laminates thereof, paper, etc. In addition, paper coated or laminated with baryta or α-olefin polymers, especially polymers of α-olefins having 2 to 10 carbon atoms, such as polyethylene, polypropylene, and ethylene butylene copolymers;
19068, the surface of which is roughened to strengthen its adhesion to other polymeric substances, or a support using the surface roughening method described in Japanese Patent Publication No. 135840/1983. can be used. Also, in order to reduce plate elongation, a support in which metal foil, for example aluminum foil, is laminated to paper can be used. Furthermore, colloidal silica can be used in a coating film applied to a polyolefin surface for the purpose of improving adhesion to a polyolefin-coated surface or improving printing suitability. Regarding these, the method described in US Pat. No. 3,161,519 may be followed. In order to strengthen the adhesion between the support and the coating layer, the surface of the support may be subjected to a preliminary treatment such as corona discharge, ultraviolet irradiation, flame treatment, or the like. Regarding corona discharge, the method described in US Patent No. 2018189 is representative. Hardening of the silver halide emulsion and/or other constituent layers can be carried out according to conventional methods. Examples of curing agents include aldehyde compounds such as formaldehyde and glutaraldehyde, ketone compounds such as diacetyl and cyclopentanedione, bis(2-chloroethyl urea), and 2-hydroxy-4,6-dichloro-1,3. , 5-triazine, etc. U.S. Patent No. 3288775, U.S. Patent No. 2732303
Compounds containing reactive halogens, divinyl sulfone, 5-acetyl-
1,3-diacryloylhexahydro-1,3,
5-triazine, etc. U.S. Pat. No. 3,635,718,
Same No. 3232763, Same No. 3490911, Same No. 3642486,
Compounds with reactive olefins such as those shown in the specifications of British Patent No. 994869, N-
Hydroxymethylphthalimide, other N-methylol compounds as shown in U.S. Patent Nos. 2,732,316 and 2,586,168, isocyanates as shown in U.S. Pat. No. 3,103,437, etc., and U.S. patents Aziridine compounds as shown in specifications such as Nos. 3017280 and 2983611, acid derivatives as shown in specifications such as U.S. Patent Nos. 2725294 and 2725295, and U.S. patents Carbodiimide compounds as shown in Specification No. 3100704 etc., U.S. Patent No. 3091537
Epoxy compounds as shown in the specifications of US Patent Nos. 3,321,313 and 3,543,292, isoxazole compounds as shown in the specifications of US Pat. , dioxane derivatives such as dihydroxydioxane and dichlorodioxane, and inorganic hardeners such as chromium alum and zirconium sulfate. In place of the above compounds, compounds in the form of breaker, such as alkali metal pisulfite aldehyde adducts, methylol derivatives of hydantoin, and primary aliphatic nitroalcohols may also be used. If necessary, known surfactants may be added alone or in combination to the printing material constituent layer of the present invention. These may be used as coating aids, but may also be used for other purposes, such as emulsification and dispersion, acceleration of development, improvement of other photographic properties, adjustment of charge series, and prevention of static electricity. These surfactants include natural products such as saponin,
Anionic or nonionic surfactants such as alkylene oxide type, glycerin type, glycidol type, higher alkylamines, quaternary ammonium salts, pyridine and other heterocycles, cationic surfactants such as phosphonium or sulfonium,
Contains anionic surfactants with acidic groups such as carboxylic acids, sulfonic acids, phosphoric acids, sulfuric esters, and phosphoric esters; amphoteric surfactants such as amino acids, aminosulfonic acids, and sulfuric or phosphoric esters of amino alcohols. It will be done. Some examples of surfactant compounds that can be used include U.S. Pat.
No. 2288226, No. 2739891, No. 2739891, No. 2288226, No. 2739891, No.
No. 3068101, No. 3158484, No. 3201253
3210191, 3294540, 3415649, 3441413, 3442654, 3475774,
British Patent No. 3545574, British Patent No. 1077317, British Patent No.
1198450, Ryohei Oda et al., "Synthesis of surfactants and their applications" (Maki Shoten, 1964)
) and AW Berry, Surf Your Active Agents (Interscience Publications, Inc., 1958), JR
It is described in "Encyclopedia of Active Age End Volume 2" by John Sisley (Chemical Publishing Company, 1964). The printing material of the present invention contains a filter dye or an anti-irradiation dye as described in the Yonegome Patent No.
It may contain the compounds described in the specifications of No. 2274782, No. 2527583, No. 2956879, No. 3177078, No. 3252921, and Japanese Patent Publication No. 39-22069. These dyes may be mordanted, if necessary, by the method described in US Pat. No. 3,282,699. Further, colored layers such as pigments (for example, lamp black, carbon black, fast black, ultramarine, malachite green, crystal violet) can also be used as the above-mentioned antihalation layer. The constituent layers of the printing material according to the present invention can be coated on the above-mentioned support using coating methods well known in the art. Examples include a dip method, an air knife method, an extrusion doctor method, and the bead coating method described in US Pat. No. 2,761,791 is particularly preferred. A silver halide developing agent may be incorporated in the constituent layers of the printing material according to the present invention. in this case,
Development after exposure can be performed by activation treatment using an alkaline aqueous solution. The developing agent is the silver halide emulsion layer or its adjacent layer (undercoat layer, intermediate layer or antihalation layer)
It can be contained inside. Note that the developer may naturally contain a developer. Specific compounds for the developer include polyhydroxybenzenes such as hydroquinone, catechol, chlorohydroquinone, pyrogallol, promohydroquinone, isopropylhydroquinone, toluhydroquinone, methylhydroquinone,
2,3-dichlorohydroquinone, 2,5-dimethylhydroquinone, 2,3-dipromohydroquinone, 1,4-dihydroxy-2-acetophenone, 2,5-dimethylhydroquinone, 4-phenylcatechol, 4-t-butyl Catechol, 4-
n-butylpyrogallol, 4,5-dipromocatechol, 2,5-diethylhydroquinone, 2,5
-benzoylaminohydroquinone, 4-benzyloxycatechol, 4-n-butoxycatechol, and the like. Among these, hydroquinone and methylhydroquinone are particularly preferably used. Other developing agents include 3-pyrazolidone compounds such as 1-phenyl-3-pyrazolidone, 1-p-tolyl-3-pyrazolidone, and 1-pyrazolidone.
-phenyl-4-methyl-3-pyrazolidone, 1
-Phenyl-4,4-dimethyl-3-pyrazolidone, 1-p-chlorophenyl-3-pyrazolidone, 1-p-methoxyphenyl-3-pyrazolidone, 1-phenyl-2-acetyl-3-pyrazolidone, 1-phenyl -5,5-dimethyl-3-pyrazolidone, 1-o-chlorophenyl-4-methyl-4-ethyl-3-pyrazolidone, 1-m-acetamidophenyl-4,4-diethyl-3-pyrazolidone, 1, 5-diphenyl-3-pyrazolidone, 1-(m-tolyl)-5-phenyl-3-pyrazolidone, 4,4-dihydroxymethyl-1-phenyl-3-pyrazolidone, 4,4-dihydroxymethyl-1-tolyl- 3-pyrazolidone, 4-
Hydroxymethyl-1-phenyl-3-pyrazolidone, 4-hydroxymethyl-4-methyl-1-
(p-chlorophenyl)-3-pyrazolidone and the like are included. In addition, as aminophenols, for example, p-
Examples include (methylamino)phenol, p-aminophenol, 2,4-diaminophenol, p-(benzylamino)phenol, and 2-methyl-4-aminophenol. The above developing agents can be used alone or in combination. In particular, a combination of a polyhydroxybenzene compound and a 3-pyrazolidone compound is preferred. The amount of the developing agent used in the constituent layers is not uniform, but it may be in the range of 0.001 g to 1 g per 1 m ² , and in the case of a silver halide emulsion layer, it is 0.01 g to 3 g.
g/g of silver halide. Further, if necessary, the constituent layers may contain a compound called a complexing agent which tends to form a soluble silver complex salt with silver halide in the unexposed area to advantageously promote physical development. Examples of complexing agents include thiosulfates, thiocyanates, amine thiosulfates as described in U.S. Pat. No. 3,169,962, or cyclic imides as described in U.S. Pat. No. 2,857,276; The mercapto compound described in Publication No. 11957/1984 can be included. The above-mentioned developing agents may be added to the coating solution after being dissolved in water or a hydrophilic solvent such as methanol, or may be added after being dissolved in a high-boiling point organic solvent or a low-boiling point organic solvent. The high boiling point organic solvent generally has a boiling point of about 180 DEG C. or higher, such as alkyl esters of phthalic acid such as ethyl phthalate and n-butyl phthalate, or phosphoric acid esters such as tricresyl phosphate.
In addition, as a low boiling point organic solvent, it is generally about 30℃~150℃.
Those having a boiling point at °C, for example, lower alkyl acetates such as ethyl acetate and butyl acetate. Further, these high and low boiling point solvents may be used in combination, and the dissolved developing agent may be dispersed in the hydrophilic colloid by any known method. When added to the constituent layers of the printing material according to the present invention, gelatin or a synthetic polymer compound such as polyvinyl alcohol, polyvinyl pyrrolidone, US Pat. Examples thereof include alkyl acrylates, sulfoalkyl acrylates, and acrylic acid copolymers described in No. 3488708. When developing the printing material of the present invention,
Processing liquids to which various substances are added can be used. Typical examples include alkaline agents (e.g. alkali metal and ammonium hydroxides, carbonates, phosphates), pH adjusting or buffering agents (e.g. weak acids and bases such as acetic acid and sulfuric acid, and their salts); Development accelerators (e.g., U.S. Pat. No. 2,648,604, U.S. Pat. No. 3,671,247)
Various pyridinium compounds and cationic compounds, potassium nitrate and sodium nitrate, U.S. Patent No. 2533990 and U.S. Pat.
Polyethylene glycol condensates and their derivatives as described in British Patent No. 2577127 and British Patent No. 2950970, etc., and polythioethers as represented by the compounds described in British Patent No. 102033 and British Patent No. 1020032. Nonionic compounds such as U.S. Patent No.
A polymer compound having a sulfite ester, as typified by the compound described in No. 3068097,
Other organic amines such as pyridine, ethanolamine, cyclic amines, benzyl alcohol, hydrazines, etc.), antifoggants (such as alkali chloride, alkali bromide, alkali iodide, and
In addition to the nitrobenzimidazoles described in US Pat. No. 2496940 and US Pat. No.
Compounds for rapid processing liquids described in specifications such as No. 3295976, No. 3615522, and No. 3597199, thiosulfonyl compounds described in British Patent No. 972211, or described in Japanese Patent Publication No. 46-41675 phenazine-N-oxides (such as those described in ``Science Photo Handbook'', pages 29 to 47 of Volume 2), and other antifoggants described in U.S. Pat.
3161513, 3161514, UK Patent No. 1030442
Stain or sludge inhibitors, as well as preservatives (e.g. sulfites, acid sulfites, hydroxylamine hydrochloride, form sulfite, alkanolamine sulfite additives, etc.) ). Also,
Sequestering agents such as sodium hexametaphosphate and ethylenediaminetetraacetic acid, wetting agents such as saponin and ethylene glycol, and the like can be used. Furthermore, the developer contains silver halide solvents such as sodium thiosulfate, sodium thiocyanate, potassium thiocyanate, alkanolamines, cyclic imines, alkyl-substituted amino alcohols, thiourea, thiosalcylic acid, and thiosalcylic acid is produced in alkaline solutions. For example, 5-methylcarbamoylthiosalicylic acid may be contained. If the printing material according to the invention needs to be stopped after development, a neutralizing solution can be used. This medium wave liquid may be a normal acid stop bath, and may have a pH adjusted to about 3.0 to 8.0. This neutralizing solution may contain a water softener, a PH regulator, a buffer, a hardening agent, etc., and may also contain colloidal silica or polyols for the purpose of eliminating ink stains on the printing plate being processed. etc. may be added. After the printing material has been processed as described above to obtain a plate, post-processing can be carried out mainly for the purpose of improving and improving printability. For example, for the purpose of improving ink receptivity, US Pat.
No. 3490906, Specification No. 3161508, Special Publication No. 1977-
No. 10910, No. 48-29723, No. 51-15762, No. 52
-15762 It is processed by the method described in each publication. Hereinafter, the present invention will be explained in more detail with reference to Examples. Example 1 A coating solution having the following composition was applied as an antihalation layer onto polyethylene coated paper (corona discharge treated) having a thickness of 160 g/m ² by a dip method. [Composition of coating solution for antihalation agent] a Carbon black 150g Gelatin 45g Finished with water 400ml b Saponin (10% aqueous solution) 10ml Matting agent (Silica Thyroid 308) 10g Finished with water 300ml c Phenidone 3.0g Hydroquinone 10.0g Methanol 40.0ml Finish with water 100ml d Formalin (35% aqueous solution) 3ml Finish with water 100ml Dissolve the above solutions a, b and c, respectively.
After dispersing, they were sequentially mixed, and then liquid d was added to prepare a final coating liquid. After coating the above coating solution as a layer, a photosensitive silver halide emulsion prepared as described below was coated on this layer. The photosensitive silver halide emulsion was a pure silver chloride emulsion prepared by the usual double-jet method, chemically sensitized with a sulfur sensitizer, and then exemplified compounds according to the present invention were added as shown in Table 1 below. Later, 4-hydroxy-6-methyl-
An appropriate amount of 1,3,3a-7-tetrazaindene was added. Subsequently, an appropriate amount of isoamyl-n-decylsulfosuccinic acid sodium salt was added as a coating aid to prepare an emulsion coating solution. The amount of silver coated is 0.8 in terms of silver.
g/ ^m2 . Seasoning treatment of the two-layer coated sample obtained above (left at 40℃, RH45% for 3 days)
Thereafter, a physical development nucleus layer coating solution having the following composition was applied to the upper layer of the coating layer by a bead coating method and dried to obtain a lithographic printing material sample according to the present invention. [Preparation of coating solution for physical development nucleus layer] a. Reaction product of polyvinyl alcohol and methyl vinyl ether maleic anhydride copolymer
40mg Gelatin 0.05g Finish with water 750ml b HAlCl ₄・4H ₂ O 0.8g Finish with water 50ml c NaBH ₄ 0.8g Finish with water 200ml After mixing the above solutions a and b at room temperature, stir vigorously. Add C solution to reduce the total amount to 1 after 10 minutes.
It was used as a stock solution for finishing physical development nuclei. An appropriate amount of saponin was added to this physical development nucleus stock solution to prepare a coating solution, which was coated at a concentration of 2.5 mg/m ² of gold. The obtained printing plate was made by the following method. Plate making method: Cylindrical scanning facsimile transmitter, neutral gray wedge, halftone wedge (120 lines/inch)
An argon laser (10mW, emission peak
Scanning exposure was performed by modulating the light output of the light source (632 nm). Subsequently, the printing material was developed with the following processing solution. Developer (alkaline activation bath) Processing time 30℃30
Anhydrous sodium sulfite 50g Potassium hydroxide 30g Hypo 2.0g Stop liquid (stabilizing liquid) to be made to 1 with water Treatment time 30℃ 30 seconds Sodium citrate 10g Citric acid 1.0g Ethylene glycol 10g Finished to 1 with water Next, the following composition After the plate surface was lightly wiped with the lipophilic liquid, printing was carried out using a printing machine also equipped with a device for supplying a dampening liquid having the composition shown below. Lipophilic liquid composition 1-p-ethoxyphenyl-5-mercaptotetrazole 0.1g Ethanol 10ml Isopropanol 20ml Add water to make up to 100ml Moisturizing liquid composition Glycerol 10ml Colloidal silica (20% liquid) 3ml Boric acid 0.5g Water to make up to 100ml Finishing The results obtained are shown in Table 1 below. In addition, the contrast in the table is expressed by gamma in the wedge part, and the halftone dots and character quality are expressed using a 5-level system, with 5 being the best for the sharpness of the image observed with a magnifying glass. In addition, the ground stains in the table are shown by the number of printed sheets in which the ground stains have occurred since printing started.

〔Effect of the invention〕

As is clear from the above examples, according to the present invention, it is highly sensitive to argon laser light, and
It is possible to provide a lithographic printing plate having excellent line drawing properties and printing characteristics free from smearing.

Claims (1)

[Scope of Claims] 1. In a silver salt diffusion transfer method lithographic printing material having a structure in which an antihalation layer and a silver halide emulsion layer are coated in layers from the support side, and then a physical development nucleus layer is coated on top of these layers. The silver halide composition is at least 98 mol% of silver chloride grains, and the silver halide emulsion contains at least one compound represented by the following general formula []. A lithographic printing material for argon laser light. General formula [] (However, A in the formula represents a lower alkyl group having 1 to 4 carbon atoms, and R ¹ and R ² represent the same or different lower alkyl group, hydroxyalkyl group, sulfoalkyl group, or carboxyalkyl group. Y ¹ and Y ²
are each an oxygen atom, and Z ¹ and Z ² represent a condensate of a benzene ring and a naphthalene ring which may have a substituent. X represents an alkali metal atom or an ammonium group, and n represents 0 or 1. )