JPH051936B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a lithographic printing material using a silver salt diffusion transfer method, and more specifically, a lithographic printing material that has excellent ink receptivity and printing durability, high sensitivity, and improved image quality. Regarding. (Prior Art) Conventionally, as the above-mentioned lithographic printing plate,
Various methods are known, but the most representative one at present is one in which a photosensitive element and a printed image element are integrated, for example, as disclosed in Japanese Patent Publication Nos. 46-42453 and 48.
The method described in Japanese Patent No. 30562 is also widely known. That is, an antihalation layer is coated on a support in order from the support side, a hydrophilic colloid layer mainly composed of a photosensitive silver halide emulsion is coated on top of the antihalation layer, and a physical development nucleus layer that becomes a printing element is further on top of that. After image exposure, silver halide particles in the unexposed area of the silver halide emulsion layer coated on the side closer to the support are transferred to the developing solution. It is dissolved by the action of the silver halide complexing agent contained therein. Then, it diffuses to the physical development nucleus layer coated on the upper side of the silver halide emulsion layer, accumulates on the physical development nucleus, and is reduced by a developing agent to form a recorded image. At the same time, the silver halide in the exposed area becomes blackened silver in the silver halide emulsion layer. In order to apply a silver image obtained by such a diffusion transfer method as an offset printing plate, the ink receptivity, or lipophilicity, of the silver image area must be high, and the ink repellency, or hydrophilicity, of the non-image area must be high. This is very important. In other words, it is important that the ink adhesion to the lipophilic image area is excellent and that the ink does not stain the hydrophilic non-image area. In addition, in the case of offset printing plates using the silver salt diffusion transfer method, in order to increase the development speed and avoid oxidation of the developing agent in the developer, it has traditionally been done to incorporate the developing agent into its constituent elements. ing. However, when a developing agent is contained in a light-sensitive material, it is unavoidable that the developing agent is oxidized in the air to some extent in the layer, which causes undesirable phenomena such as deterioration of developability, increased fog, and softening of contrast. It is customary. Particularly in the case of silver salt diffusion transfer lithographic printing materials, the amount of silver halide that is dissolved by the action of the silver halide complexing agent contained in the alkaline active bath due to the occurrence of fog in the unexposed areas due to chemical development. decreases,
A problem arises in that a sufficient lipophilic silver image as a printing plate cannot be formed on the physical development nuclei. Many reports have been made regarding methods for suppressing fog in silver halide emulsions, but all of them are related to desensitization, background smearing due to decreased hydrophilicity in non-printing areas, and softening of originals in silver halide lithographic printing plates. This was accompanied by undesirable effects such as the appearance of pasting marks during photography. Furthermore, when only potassium bromide, a typical inorganic inhibitor, is used as a fog inhibitor, desensitization, softening, and fog during chemical development are greatly suppressed, but at the same time, the precipitation of silver images on physical development nuclei is suppressed. The idea was that it would also suppress it. These lithographic printing materials produced by the silver salt diffusion transfer method are usually prepared in the form of a roll using paper or film base as a support, and then photographed and developed using a plate-making machine using a lens system to obtain a printing plate. Alternatively, a plate-making method using an image recording means using a scanning system using LED light as a light source has been put into practical use.
A feature of these methods is that images with extremely high sharpness and resolution can be obtained compared to conventional methods, but on the other hand, there is a problem in that exposure is performed for an extremely short time using a luminous flux of high illuminance. Therefore, silver halide lithographic printing materials suitable for platemaking using lasers or LEDs have high sensitivity and high sensitivity during high-intensity exposure.
It is required to show contrast. On the other hand, silver halide photosensitive materials usually suffer from a phenomenon called high-intensity reciprocity failure, in which when exposed to high-intensity light for an extremely short period of time, the sensitivity contrast decreases significantly compared to when exposed to normal light. . For this reason, the photosensitive material used when recording an image by scanning exposure using a laser or LED as a light source as described above is required to have a high illumination intensity and a small reciprocity law failure. Many methods have been proposed to suppress high-intensity reciprocity failure in silver halide emulsions, and the addition of iridium compounds is known to be particularly effective. When applied to printing materials, the reality is that it is still not possible to prevent desensitization, softening of tone, deterioration of printing characteristics, etc. during high-intensity, extremely short-time exposure. (Objective of the Invention) The object of the present invention is to provide a silver salt diffusion transfer method that has photographic properties suitable for high sensitivity, high contrast, high illuminance, and extremely short exposure, and has good ink receptivity and high printing durability. An object of the present invention is to provide a lithographic printing material containing a developing agent according to the present invention. (Structure of the Invention) As a result of intensive research, the present inventors have discovered that the present invention is constructed by laminating at least one layer each of an antihalation layer, a silver halide emulsion layer, and a physical development nucleus layer on a support in order from the support side, and Silver containing in said component an amount of a developing agent sufficient to effect development of the silver halide in said silver halide emulsion layer exposed in an alkaline activation bath and physical development in a physical development nucleus layer. In the salt lithography printing material, the silver halide emulsion constituting the silver halide emulsion layer contains 95 mol% or more of silver chloride and an iridium compound, and the odor on the outer surface of the silver halide grains constituting the emulsion is It has been found that the above object can be achieved by a silver salt lithographic printing material characterized in that the content of silver oxide is higher than the content of silver bromide inside the grains. The silver halide emulsion used in the present invention will be explained below. The silver halide emulsion used in the present invention is mainly silver chloride, and preferably contains silver chloride in an amount of 95 mol % or more, particularly preferably 98 mol % or more. If the amount of silver chloride is less than 95 mol %, the amount dissolved by the silver halide complexing agent will be small, and the resulting lipophilic silver image will be weak in strength.
Silver bromide is contained in an amount of 0.1 to 5 mol%, preferably 0.2 to 2 mol%. Methods for producing particles with a high silver bromide content on the outer surface include a method in which an aqueous solution of silver nitrate and a bromine salt are added to a core particle prepared in advance to form an outer shell, and a method in which particles consisting mainly of silver chloride are produced. There is a method in which a portion of the silver bromide is converted into silver bromide by adding a bromine salt, but among these methods, a conversion method is preferred. The conversion with a bromine salt can be carried out at any time after grains mainly composed of silver chloride are formed, for example, during physical ripening, before chemical ripening, after chemical ripening, or after addition of a sensitizing dye. Silver bromide can also be contained inside the grains by a conventional method at a lower concentration than the silver bromide on the surface. The above-mentioned silver chlorobromide can further contain an effective amount of silver iodide for increasing the contrast in a well-known manner. The content of silver iodide is preferably 1 mol% or less,
It can be incorporated by the same method as for silver bromide described above. The silver halide grains preferably have an average size in the range of 0.05μ to 2.0μ. The iridium compound used in the present invention is
For example, iridium chloride (), iridium chloride (), potassium hexachloroiridate (), potassium hexachloroiridate (),
Examples include, but are not limited to, sodium hesachloroiridate (), sodium hexachloroiridate (), and the like. Although the amount added varies depending on the conditions and is not constant,
The amount is in the range of 10 ^-9 to 10 ^-4 mol, preferably 10 ^-8 to 10 ^-5 mol per mol of silver halide. There are two ways to include it: doping by adding it in the form of an iridium compound during the mixing of silver nitrate and a halide salt, and adding it after mixing. The method of addition during mixing is preferably in the solution of the halogen salt. The addition after mixing can be carried out at any time after the silver halide grains are formed, but it is preferably added in the form of an aqueous solution during physical ripening or before chemical ripening. The present invention has a silver halide emulsion layer made of silver chlorobromide containing these iridium compounds, and development of the exposed silver halide and physical development in the physical development core layer are carried out by alkaline activation bath treatment. The developing agent is contained in the constituent elements in an amount sufficient to carry out the process. In other words, although the objective of the present invention could not be achieved with each of the above requirements alone, as a result of intensive studies by the present inventors, it has been found that silver salt lithographic printing materials containing a developing agent as a component can be It has been discovered that when a silver halide emulsion consisting of silver halide grains having the same composition and containing an iridium compound is used, extremely good high illuminance characteristics can be obtained, and that the object of the present invention can be achieved for the first time. The effect is something that could not have been expected from the conventional technology. In other words, the silver halide lithographic printing material obtained in this way hardly causes high-intensity reciprocity failure, does not deteriorate sensitivity or contrast even during high-intensity, extremely short-time exposure such as laser or LED scanning exposure, and exhibits no fogging. Since the level is low, an extremely clear image can be obtained, and since the amount of image silver formed in the physical development layer is high, a lithographic printing plate with good ink receptivity and a high printing life can be obtained. The present invention will be explained in more detail below. As described above, the silver salt offset printing material of the present invention (hereinafter simply referred to as the printing material of the present invention) has an antihalation layer, a photosensitive silver halide emulsion layer, and a physical development nucleus layer on the support. Although the basic layer structure is provided with , an intermediate layer can also 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. The method for preparing the silver halide emulsion according to the present invention may be any method well known in the art, such as a single jet method, a double jet method, or a controlled jet method. 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 salts of noble metals such as platinum, palladium, rhodium, and ruthenium, which are described in Japanese Patent Nos. 2,566,263 and 2,598,079. Spectral sensitization can also be carried out using various sensitizing dyes if necessary. The hydrophilic binder advantageously used in the silver halide emulsion according to the present invention is gelatin, and a part or all of the gelatin can be substituted with a synthetic high-molecular polymer such as polyvinyl alcohol, poly-N-
vinyl pyrrolidone, 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, hardening agents,
Various additives such as surfactants can be used as appropriate.For specific compound examples, see "Product Licensing Index" Volume 92, No.
9232, pp. 107-110, ~, ~,
, (December 1971). 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, palladium, zinc, lead, cadmium, etc.
Metal colloids obtained by reducing heavy metals such as nickel, cobalt, iron, chromium, tin, antimony, bismuth, etc., or water-soluble metal salts thereof, such as nitrates, acetates, borates,
Development nuclei obtained by mixing chloride, hydroxide, etc. with a water-soluble sulfide, such as sodium sulfide, etc. can be used. As for the type of hydrophilic binder used in the physical development nucleus layer according to the present invention, hydrophilic polymer substances of the same type as those used in the photosensitive silver halide emulsion layer described above are applicable, including gelatin, polyvinyl alcohol, 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 is within a range of 100% or less 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. The support for the lithographic printing material according to the present invention includes:
Examples include nitrate film, cellulose acetate film, cellulose acetate butyrate film, polystyrene film, polyethylene phthalate film, polycarbonate film, laminates thereof, and paper. 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,
47-19068, in which the adhesion with other polymeric substances is strengthened by roughening the surface, or the surface roughening method described in Japanese Patent Publication No. 135840, 1983, etc. A support 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. Further, 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 printability. 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 layer 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, and other U.S. patents
3635718, 3232763, 3490911, 3642386, British Patent No. 994869, compounds with reactive olefins, N-hydroxymethylphthalimide, and other US patents N-methylol compounds as shown in the specifications of No. 2732316 and No. 2586168, isocyanates as shown in U.S. Patent No. 3103437, and U.S. Patent No. 3017280 and No. 2983611. Aziridine compounds as shown in each specification, U.S. Patent No. 2725294, U.S. Patent No.
Acid derivatives as shown in specifications such as No. 2725295, carbodiimide compounds as shown in US Pat. No. 3,100,704, etc., and carbodiimide compounds as shown in US Pat. No. 3,091,537, etc. epoxy compounds such as, isoxazole compounds as shown in U.S. Pat. Derivatives, silane coupling agents described in Japanese Patent Application No. 58-354, and inorganic hardeners include chromium alum and zirconium sulfate. Also, those in the form of precursors instead of the above compounds,
For example, alkali metal bisulfite aldehyde adducts, methylol derivatives of hydantoin, primary aliphatic nitro alcohols, and the like may be used. If necessary, known surfactants may be added to the constituent layers of the lithographic printing material of the present invention, either singly or in combination. 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, glycerin, and glycidol,
Higher alkylamines, quaternary ammonium salts, pyridine and other heterocycles, cationic surfactants such as phosphonium or sulfonium, carboxylic acids, sulfonic acids, phosphoric acids, sulfuric esters,
Included are anionic surfactants having an acidic group such as phosphoric acid esters, and amphoteric surfactants such as amino acids, aminosulfonic acids, and sulfuric acid or phosphoric acid esters of amino alcohols. 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, No. 3210191, No. 3294540, No. 3415649,
Same No. 3441413, Same No. 3442654, Same No. 3475774,
British Patent No. 3545574, British Patent No. 1077317, British Patent No.
1198450, as well as Ryohei Oda et al., "Synthesis of surfactants and their applications" (Shoten, 1964)
) and AW Berry, Surf S Active Agent (Interscience Publications, Inc., 1958), JP
It is described in "Encyclopedia of Active Agents Volume 2" by John Sisley (Chemical Publishing Company, 1964). The offset printing material of the present invention may contain filter dyes or anti-irradiation dyes as described in U.S. Pat.
It may contain compounds described in the specifications of 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. Furthermore, colored layers such as pigments (for example, lamp black, carbon black, fest black, ultramarine, malachite green, crystal violet) can also be used as the above-mentioned antihalation layer. The constituent layers of the lithographic 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 dip method, air knife method, extrusion doctor method, etc., and particularly preferred is the bead coating method described in US Pat. No. 2,761,791. A silver halide developing agent is incorporated in the constituent layers of the lithographic printing material according to the present invention. In this case, development after exposure can be carried out by activation treatment using an alkaline aqueous solution. The developing agent is used in the silver halide emulsion layer, antihalation layer, or adjacent layer (undercoat layer, intermediate layer).
Although it can be contained in the antihalation layer, it is most preferably contained in the antihalation layer. Note that a developer may also be included in the alkaline aqueous solution used for development. Specific compounds for the developer include polyhydroxybenzenes such as hydroquinone, catechol, chlorohydroquinone, pyrogallol, bromohydroquinone, isopropylhydroquinone,
toluhydroquinone, methylhydroquinone, 2,3
-dichlorohydroquinone, 2,5-dimethylhydroquinone, 2,3-dibromohydroquinone, 1,
4-dihydroxy-2-acetophenone, 2,5
-dimethylhydroquinone, 4-phenylcatechol, 4-t-butylcatechol, 4-n-butylpyrogallol, 4,5-dibromocatechol,
Included are 2,5-diethylhydroquinone, 2,5-benzoylaminohydroquinone, 4-benzyloxycatechol, 4-n-butoxycatechol, and the like. Among these, hydroquine and methylhydroquinones 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-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-4-methyl-1-phenyl-
3-pyrazolidone, 4-hydroxymethyl-4-
Included are methyl-1-(p-chlorophenyl)-3-pyrazolidone and the like. In addition, as aminophenols, for example, p-
(Methylamino)phenol, p-aminophenol, 2,4-diaminophenol, p-(benzylamino)phenol, 2-methyl-4-aminophenol, 2-hydroxymethyl-4-aminophenol, etc. . 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. Although the amount of the developing agent used in the constituent layers is not uniform, 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 per m 2 .
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 US Pat. No. 3,169,962, or cyclic imides as described in US Pat. No. 2,857,276; Maleic acid hydrazides described in Japanese Patent Application No. 1988-1953, mercapto compounds described in Japanese Patent Publication No. 46-11957, and the like 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, and includes, for example, 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℃.
It has a boiling point at ℃, such as 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. In addition, when adding it to the constituent layers of the lithographic printing material according to the present invention, it can be added directly to any layer, or
Alternatively, gelatin or a synthetic polymer compound such as polyvinyl alcohol, polyvinyl pyrrolidone, alkyl acrylate, sulfoalkyl acrylate, or acrylic acid copolymer described in US Pat. No. 3,488,708 can be used. When the lithographic printing material of the present invention is subjected to alkali activation treatment after exposure, a treatment liquid 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, and polythioethers as represented by the compounds described in British Patent No. 1020033 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, cyclic imides, maleic acid hydrazides, alkyl-substituted amino alcohols, thiourea, thiosalcylic acid, It can contain, for example, 5-methylcarbamoylthiosalcylic acid, which can form thiosalcylic acid in alkaline solution. If it is necessary to stop the development of the lithographic printing material according to the present invention after development, a neutralizing solution can be used. This neutralizing solution can be a normal acid stop bath, and the pH
is adjusted to approximately 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 is treated as described above to obtain a plate, various post-treatments can be carried out for the purpose of 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. [Preparation of coating solution for antihalation layer] a Carbon black dispersion (EMP Black manufactured by Toyo Ink) Finished with gelatin water 60 g 45 g 400 m b Saponin (10% aqueous solution) Matting agent (Silica Thyroid 308) Finished with water 10 m 10g 300m c Phenidone Hydroquinone Finished with methanol water 3.0g 10.0g 40.0m 100m d Formalin (35% aqueous solution) Finished with water 100m 3m 100m 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 layer prepared as described below was coated on this layer. [Preparation of silver halide emulsion] Emulsion-1 A water gelatin NaC Adjust to PH3.0 with antifoaming agent sulfuric acid 250c.c. 10g 1.5g 0.1g B water silver nitrate 350c.c. 60g C water NaC Na ₃ RhC ₆ 350c .c. 25 g 1.5×10 ^-5 g Potassium hexachloroiridate () Na ₃ IrC ₆ was added to Solution C as shown in Table 1. Solutions A and C at 55°C were added at a constant rate over 30 minutes, followed by water washing. Emulsion 2 Emulsion 2 was prepared in the same manner as Emulsion 1 except that Solutions B and C were added over 70 minutes. [Coating of silver halide emulsion] 5,5' diphenyl-
After adding 100 mg of 3,3' diethyl-9ethyl-oxacarbocyanine-bromine salt and adsorbing it for 10 minutes,
Halogen conversion was carried out by adding an aqueous potassium bromide solution as shown in Table 1. Subsequently, 300 mg of 4hydroxy-6-methyl-1,3,3a,7-tetrazaindene and gelatin were added as a stabilizer, and finally, an appropriate amount of isoamyl-n-decylsulfosuccinic acid sodium salt and formaldehyde emulsion were added as coating aids. A coating solution was prepared by adding 60 mg per gram of gelatin in the layer. The amount of silver coated was 1 g/m ² in terms of silver, and the amount of gelatin coated in the silver halide emulsion layer was 2 g/m ² . Seasoning treatment of the two-layer coated sample obtained above (left at 40℃, RH45% for 3 days)
Thereafter, a physical development nucleus layer coating liquid having the following composition was applied to the upper layer of the coating layer by an air knife 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 Polyvinyl alcohol and methyl vinyl ether Reaction product with maleic anhydride copolymer Gelatin Finished with water 40mg 0.05g 750m bHAuCl ₄・4H ₂ O Finished with water 0.8g 50m cNaBH ₄ Finish with water 0.8g 200m After mixing the above liquids a and b at room temperature, add liquid c under strong stirring for reduction, and after 10 minutes reduce the total amount to 1
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 an amount of 2.5 mg/m ² of gold. The obtained printing plate material was plate-made by the following method. Exposure method A xenon lamp was used for exposure for 10 ^-2 seconds (exposure method 1) and for 10 ^-6 seconds (exposure method 2). At this time, a neutral gray ND filter was used to adjust the exposure amount for the above exposure methods 1 and 2 to be the same. Alkaline activation bath treatment [treatment time 30℃~30
Composition Anhydrous sodium sulfite 50g Potassium hydroxide 30g Sodium thiosulfate 2g Finish to 1 with water Stop bath treatment [Processing time 30°C to 30 seconds] Composition Sodium citrate 10g Citric acid 1.0g Ethylene glycol 10g Finish to 1 with water. The obtained sensitometric results and printing durability test results are shown in Table 1 below. In addition, the relative sensitivity in the table is
It is expressed as a relative sensitivity when the sensitivity when sample 9 was exposed using exposure method 1 was set as 100. Gamma is expressed as a distribution in the straight line portion of the characteristic curve.

[Table] As is clear from Table 1, the sensitivity of the method of the present invention is high, and even with high-intensity short-time exposure, no decrease in sensitivity is observed, and the contrast is high. It also shows that it has excellent printing durability. [Example 2] Samples as shown in Table 2 below were prepared according to Example 1. The obtained offset printing material was processed in the same manner as in Example 1 after photographing the original using a plate-making camera to obtain a printing plate. However, samples in which no developer was added to the antihalation layer were developed with the developer shown below at 30° C. for 30 seconds, and all subsequent treatments were carried out in the same manner to obtain the respective printing plates. Developer composition [Processing time 30℃ 30 seconds] Phenidone 1.0g Anhydrous sodium sulfite 50g Hydroquinone 6.0g Sodium thiosulfate 2g Potassium hydroxide 30g After development and stopping, the surface of the printing plate obtained was lightened with a lipophilic liquid of the following formulation. After the wiping process, printing was carried out using a printing machine also equipped with a device for supplying a dampening liquid as described below. Lipophilic liquid composition 1-p-ethoxyphenyl-5-mercaptotetrazole 0.1g Ethanol 40ml Ethylene glycol 5ml Add water to 100ml Moisturizing liquid composition Ethylene glycol 100g Colloidal silica (20% liquid) 20g Boric acid 5g Sodium sulfate ( Anhydrous) 10g Add water 1 Note that the ink receptivity, ground staining, printing durability, and dampening test in Table 2 indicate the results evaluated by the following methods. Ink receptivity: As soon as the ink roller and plate surface come into contact, paper feeding begins and is evaluated by the number of prints until a good print with high print density is obtained. ○: Obtained within 10 sheets. △: Obtained within 30 sheets. ×: Prints with high density cannot be obtained even after 50 sheets or more. Ground stains: Evaluated by the density of background stains in the white area of the 500th printed page. ○: No stains occur on the ground. △: Thin dirt is partially generated. ×: High concentration of dirt on the entire surface. Printing durability: Evaluated by the number of prints printed continuously that become defective due to a decrease in ink density, blurred images, smudges, etc. ○: Good even for 5000 sheets or more. △: A defect occurred between 3000 and 4000 sheets. ×: Failure occurred when the number of sheets was 3000 or less. Dampening test After 500 revolutions of dry running with only the dampening liquid supplied onto the plate surface, when printing is started by contacting the ink for the first time, test how many sheets of good quality printed matter can be obtained. As a result, the lower the number, the less wear (defective printed matter) there is, and it can be said that the printing plate has printing durability.

[Table] As seen in Table 2, sample 14 according to the present invention,
It is clear that Sample No. 15 is superior to Comparative Samples Nos. 16 to 23 in all properties of ink receptivity, scumming, printing durability, and dampening test. [Example 3] A base paper weighing 130 g/m ² is laminated with aluminum foil having a thickness of 10 microns. Using a support with a subbing process applied to the surface of the aluminum foil, the coating composition of the physical development nucleus layer is prepared as follows. A printing plate material was prepared in the same manner as in Example 1 except that . However, 100mg of the following compound [] is added to emulsions 1 and 2.
and adsorption at 50°C for 10 minutes to perform color sensitization. (Coating liquid composition for physical development nucleus layer) [Liquid A] Binder (reactant of Denka Poval K-20 and Gantolets) 0.2g Water 434c.c. [Liquid B] pdC ₂ 0.7g 1N-HC 5.3cc Water 150c .c. Heat at 50℃ for 10 minutes, dissolve, and then cool. [Liquid C] Na ₂ S・9H ₂ C 1.4 g Water 400 c.c. After mixing the above liquids A and B, add liquid C while stirring at 15°C. After 30 minutes of reaction, it was purified by ultrafiltration. An appropriate amount of sodium isoamyl-n-decylsulfosuccinate was added as a coating aid to the above-mentioned coating solution for the physical development nucleus layer. The prepared printing plate samples were processed as in Example 1. However, the plate was made using the following exposure method. Exposure method: Cylindrical scanning facsimile transmitter with neutral gray wedge, halftone wedge (120
A helium-neon laser (10mW, emission peak Scanning exposure was performed by modulating the light output of the light source (632 nm). The properties obtained are shown in Table 3 below.

[Table] The gamma in the table represents the gamma of the linear part of the characteristic curve in the wedge part, and the halftone dot and character quality are evaluated on a 5-point scale, with 5 being the best, based on the sharpness of the image observed with a magnifying glass. It is something. In addition, printing durability was evaluated by the number of prints that became defective due to a decrease in ink density, blurred images, smearing, etc. during continuous printing. From Table 3 above, samples obtained by the method of the present invention
24 and 25 are printing plates that have better line drawing properties than comparative samples 26 to 30, have high sensitivity even under high-intensity short-time exposure, and have excellent printing durability. has been proven. (Effects of the Invention) As is clear from the above examples, the present invention has photographic characteristics suitable for high sensitivity, high contrast, and high-intensity short-time exposure, and has high ink receptivity and high resistance. It is possible to provide a lithographic printing material containing a developing agent produced by the silver salt diffusion transfer method.

Claims (1)

[Claims] 1 Consisting of at least one layer each of an antihalation layer, a silver halide emulsion layer, and a physical development nucleus layer layered on a support in order from the support side, and the above components are exposed to light by an alkali activation treatment. In a silver salt lithographic printing material containing a sufficient amount of a developing agent to carry out the development of silver halide in the silver halide emulsion layer and the physical development in the physical development nucleus layer, the silver halide emulsion layer constitutes the silver halide emulsion layer. The silver halide emulsion contains 95 mol% or more of silver chloride and an iridium compound, and the silver bromide content on the outer surface of the silver halide grains constituting the emulsion is lower than the silver bromide content inside the grains. A silver halide lithographic printing material characterized by a higher rate.