JPH0444738B2 - - 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 using a silver salt diffusion transfer method that has excellent ink receptivity and improved background smearing. Concerning printing materials. PRIOR ART Many lithographic printing materials using the silver salt diffusion transfer method have been known, but representative printing materials include a photosensitive photographic element and a physical development nucleus layer which is a printed image element. Printing materials having an integral structure are described in, for example, Japanese Patent Publication No. 46-42453 and Japanese Patent Publication No. 48-30562. By the way, in general, the printing surface of a lithographic printing plate is composed of an image area that is lipophilic and has ink receptivity, and a non-image area that has ink repellency, so lithographic printing materials that use the silver salt diffusion transfer method In this case, the silver image deposited on the surface of the printing plate by the diffusion transfer method can be used as a lipophilic image area, and the area where the silver image has not been deposited can be used as a hydrophilic, ie, ink-repellent, non-image area. When printing using such a lithographic printing material as described above, water and ink are simultaneously supplied to the plate surface so that the image area receives the ink, and water is selected for the non-image area. to be accepted,
Next, a printed matter is obtained by transferring only the ink in the image area to paper. Therefore, in order to obtain good printed matter, it is an important factor that the difference between the image area and the non-image area, that is, the difference between hydrophobicity and hydrophilicity, is clear. However, in lithographic printing materials produced by the silver salt diffusion transfer method, the difference between hydrophobicity and hydrophilicity is not necessarily clear; for example, if enough ink is supplied to the image area, the ink will adhere to the non-image area; As a result, ink may adhere to the white background of printed matter, causing so-called background stains. Several proposals have been made to date regarding methods for preventing such scumming. For example, Japanese Patent Publication No. 55-19756 describes a technique to improve the surface of the printing material by roughening it with fine powder, and further support. An improved technique for roughening the body is disclosed. Further, ``Photographic Silver Halide Diffusion Process of Focal Press Co.'' describes an improved method by using carboxymethyl cellulose as a binder in the physical development nucleus layer. However, even if these disclosed methods are used, it is impossible to completely prevent background smudges as described above, and the conventional techniques have narrow tolerances for printing conditions and are difficult to use. Therefore, improving background smearing is an important issue for printing technology. OBJECTS OF THE INVENTION An object of the present invention is to provide a lithographic printing material using a silver salt diffusion transfer method that has excellent ink receptivity in the image area of a printing plate and does not cause scumming. Structure of the Invention The object of the present invention is to provide a lithographic printing material using a silver salt diffusion transfer method having, in order from the support side, a silver halide emulsion layer and a physical development nucleus layer, in which the silver halide emulsion layer has an average grain size. It has been found that this can be achieved by a lithographic printing material containing fine particle powder of 1 μm to 10 μm and containing carboxymethylcellulose as a binder for the physical development core layer with a degree of polymerization of 700 or less. The present invention will be explained in more detail below. The lithographic printing material of the present invention has a silver halide emulsion layer and a physical development nucleus layer on a support as described above, and an antihalation layer, a silver halide emulsion layer, and a physical development nucleus layer are sequentially formed from the support side. The antihalation layer according to the present invention is a colored layer containing a photographic filter dye, an antihalation dye, a pigment, etc., which are normally used in photographic light-sensitive materials. Examples of the above-mentioned colorants include US Pat. No. 2,274,782, US Pat.
It may contain compounds described in the specifications of 3177078 and 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. In addition, pigments (for example, lamp black, carbon black, fast black, ultramarine,
malachite green, crystal violet)
Colored layers such as can be used. Next, regarding the silver halide emulsion layer coated on the above-mentioned antihalation layer, the silver halide emulsion of the emulsion layer is silver chloride, silver chlorobromide, silver chloroiobromide prepared by a conventional method. Any emulsion consisting of silver, silver bromide, silver iodobromide, etc. may be used, but if silver chloride is about 50%
Emulsions containing mol % or more are preferred. There are no particular restrictions on the grain size, crystal habit, etc. of the silver halide used.
Conventionally known methods can be used for the preparation. The silver halide emulsion used in the present invention can be chemically sensitized by known methods such as gold sensitization, sulfur sensitization, etc., and can also be spectrally sensitized by using a sensitizing dye. Furthermore, in the silver halide emulsion, an anti-capri agent, a stabilizer, a hardening agent, a surfactant, a development accelerator,
It is also possible to contain commonly used additives such as a developing agent and a matting agent. As mentioned above, one of the features of the silver halide emulsion layer according to the present invention is that it contains fine grain powder having an average grain size of 1 to 10 microns. As the fine particle powder, for example, an organic synthetic polymer compound such as polymethyl methacrylate, or an inorganic compound such as silica, aluminum oxide, or titanium oxide can be used, and there is no particular restriction on the amount of such fine particle powder added. No, but the above emulsion layer
Preferably it is between 1.5 and 15 mg per dm ² . In the present invention, a physical development nucleus layer is coated on the silver halide emulsion layer. As the physical development nuclei of this physical development nucleus layer, for example, metals such as antimony, bismuth, cadmium, cobalt, palladium, nickel, gold, silver, zinc, etc. and their sulfides can be used as colloids dispersed. can. In the physical development nucleus layer according to the present invention, the hydrophilic binder (described below) in which the above metal or metal sulfide is colloidally dispersed contains at least one type of carboxymethyl cellulose, and the average degree of polymerization of this carboxymethyl cellulose is 700. It is characterized by the following: The carboxymethylcellulose used in the present invention has a chemical structure as shown below, and has one carboxymethyl group per unit of anhydroglucose, and generally has a degree of etherification of 1.0. It is called. In addition, in the repeating unit, the carboxy group is an alkali metal (e.g. potassium, sodium)
It may also contain substances that form salts. (carboxymethyl cellulose) (n: degree of polymerization) As the anhydroglucose of cellulose has three OH groups per unit as mentioned above, the degree of etherification can theoretically be up to 3, but many of the products currently on the market are The main ones are about 0.6 to 1.0. The carboxymethylcellulose according to the present invention has an average degree of polymerization (n) of 100 to 700 and an average molecular weight of 24,000.
to 169,000, particularly preferably those having an average degree of polymerization of 100 to 400 and an average molecular weight of 24,000 to 97,000 are used. These compounds are commercially available from Daiichi Kogyo Seiyaku Co., Ltd., for example, under the trade name "Celogen". According to the present invention, if the average degree of polymerization of carboxymethyl cellulose contained in the physical development nucleus layer is 700 or more, poor inkling occurs in printed matter and clear printed matter cannot be obtained. It has been found that when carboxymethyl cellulose having an average degree of polymerization of 700 or less is contained, printed matter with improved scumming can be easily obtained without reducing the ink receptivity. The reason for this is not necessarily clear, but carboxymethylcellulose with a low average degree of polymerization of 700 or less, as in the present invention, is less likely to stick to the physically developed silver surface that forms the image area than carboxymethylcellulose, which has a higher degree of polymerization. Therefore, it is likely to be easily removed from the surface of physically developed silver during development or at the initial stage of printing, and it is thought that by increasing hydrophobicity, receptivity to lipophilic ink is increased and ink receptivity is improved. On the other hand, in the non-image area, carboxymethyl cellulose has a strong affinity for the gelatin or the above-mentioned fine particle powder used in the silver halide emulsion layer coated below the physical development nucleus layer, so that the carboxymethyl cellulose adheres to the surface of the printing plate. It is interpreted that carboxymethylcellulose, which has a low degree of polymerization, increases the hydrophilicity of the non-image area and repels ink, thereby preventing scumming. The amount of carboxymethyl cellulose with a low degree of polymerization used in the present invention is not particularly limited, but is preferably 20% (weight) or more of the total amount of the binder used in the physical development nucleus layer. The carboxymethyl cellulose may be used before or during the chemical reaction of physical development nuclei, or after the formation of physical development nuclei. Other binders that can be used in combination with carboxymethyl cellulose in the present invention include, for example, gelatin, gelatin in which part or all of gelatin has been replaced with a synthetic polymer substance, or a reagent that can react with a functional group in gelatin. Gelatin derivatives treated with can be widely used. Also casein, albumin, hydroxyethylcellulose, agar, sodium alginate, starch derivatives, sugar derivatives, polyvinyl alcohol, polyN-vinylpyrrolidone, polyacrylic acid, polyacrylamide, maleic anhydride-vinyl acetate copolymer, maleic anhydride-methyl It is also possible to use a combination of a vinyl ether copolymer, a half ester thereof, a methacrylic acid copolymer, and the like. In the present invention, a hydrophilic binder can be used to constitute the antihalation layer and the silver halide emulsion layer, but the hydrophilic binder is the same as the binder that can be used in combination with carboxymethyl cellulose. These may be used alone or in combination of two or more. In addition to the three layers described above, the lithographic printing material of the present invention may optionally include an intermediate layer as a constituent layer;
Auxiliary layers etc. may also be provided. To further describe the present invention in detail, 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, glycidol, and fluorine, higher alkylamines, quaternary ammonium salts, pyridine and other heterocycles, and cationic surfactants such as phosphonium or sulfonium. , anionic surfactants with acidic groups such as carboxylic acids, sulfonic acids, phosphoric acids, sulfuric esters, and phosphoric esters; amphoteric surfactants such as amino acids, amino sulfonic acids, and sulfuric or phosphoric esters of amino alcohols. included. 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.'s "Synthesis of Surfactants and Their Applications" (Maki Shoten, 1964)
) and “Surf S Active Agents” by A.M. Schwartz & J.W. Perry (Interscience Publications, Inc.)
(1958), "Encyclopedia of Active Agents Volume 2" by J.P. Sisley (Chemical Publishing Company, 1964), etc. 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 a dip method, an air knife method, an extrusion doctor method, and a particularly preferred method is the pea coating method described in US Pat. No. 2,761,791. A silver halide developing agent may be incorporated into the constituent layers of the lithographic printing material according to the present invention, if necessary. In this case, development after exposure can be carried out by activation treatment using an alkaline aqueous solution. The developing agent is the silver halide photosensitive layer or its adjacent layer (undercoat layer, intermediate layer, or antihalation layer).
It can also be contained therein. Note that the developer may naturally contain a developer. 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 terephthalate film, polycarbonate film, paper, and aluminate base paper. Furthermore, baryta or α-olefin polymers having 2 to 10 carbon atoms, such as polyethylene, polypropylene, ethylene butylene copolymers, etc.
A base paper coated or laminated with an olefin polymer can be used as the support. In addition, the surface of the support was subjected to corona discharge, ultraviolet irradiation,
The adhesion between the support and the coating layer may be enhanced by pre-treatment such as flame treatment or by subbing treatment. Hereinafter, the present invention will be specifically explained with reference to Examples. Example 1 Coating solutions having the following compositions were prepared for the antihalation layer and the silver halide emulsion layer. [Preparation of coating solution for antihalation layer]

[Preparation of coating solution for silver halide emulsion]

A neutral silver chlorobromide emulsion containing 95 mol% silver chloride and 5 mol% silver bromide prepared by a conventional method was chemically ripened and ortho-sensitized. -6-methyl-1,3,3a,
An appropriate amount of 7-tetrazaindene was added. Subsequently, as shown in Table 1 below, fine particle powder of silica was added and stirred to disperse it, and then an appropriate amount of isoamyl-n-decylsulfosuccinic acid sodium salt was added as a coating aid to prepare a silver halide emulsion coating solution. . Note that the gelatin content was 5%. The antihalation coating solution and silver halide emulsion coating solution obtained in this way were each
On a polyethylene coated paper (after corona discharge treatment) having a thickness of 135 g/m ² , an antihalation layer was applied as a lower layer and a silver halide emulsion layer was applied as an upper layer, which were simultaneously coated in multiple layers by a bead coating method and dried. At this time, the coating amount of gelatin in the antihalation layer and silver halide emulsion layer was 30mg/each.
dm ² and 20 mg/dm ² , and the coating amount of the silver halide emulsion was 10 mg/dm ² in terms of silver. Seasoning treatment of the two-layer coated sample obtained above (left at 40℃, RH45% for 3 days)
Thereafter, a coating liquid for a physical development nucleus layer having the following composition was applied to the upper layer of the coating amount 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]

[Alkali activation bath]

Anhydrous sodium sulfite 60g Potassium hydroxide 30g Sodium thiosulfate 0.5g Add water to make 1. Next, the plate surface was wiped with the following lipophilic liquid, and then printing was carried out using a printing machine equipped with a device for supplying a dampening liquid having the same composition as shown below. [Lophophilic liquid] 1-p-ethoxyphenyl-5-mercaptotetrazole 0.1 g Ethyl alcohol 40 ml Ethylene glycol 5 ml Add water to make up to 100 ml. [Moisturizing liquid] Ethylene glycol 100g Colloidal silica (20% liquid) 20g Boric acid 5g Sodium sulfate (anhydrous) 10g Add water to make 1. The obtained printing characteristics are shown in Table 1 below, and the printing evaluation in the table was determined by the following method. 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. 〇: Obtained within 10 pieces. △: 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 dirt occurs on the ground. △: Thin dirt is partially generated. ×: High concentration of dirt on the entire surface. The results obtained are shown in Table 1 below.

[Table] As is clear from the results in Table 1 above, the physical development nucleus layer contains carboxymethyl cellulose with a degree of polymerization of 700 or less, and the silver halide emulsion layer contains fine grain powder with an average grain size of 1 μ to 10 μ. It was found that all the lithographic printing materials according to the present invention have excellent ink receptivity and have little background staining on printed matter. Example 2 A coating solution for a physical development nucleus layer having the following composition was prepared, a binder as shown in Table 2 below was added to the coating solution, and this was mixed with the same antihalation layer and silver halide layer as in Example 1. A lithographic printing material according to the present invention was prepared by coating the coating layer on top of the emulsion layer. A printing test was conducted in the same manner as in Example 1 on the lithographic printing material sample thus obtained. [Preparation of coating solution for physical development nucleus layer]

[Table] After mixing the above solutions a and b at room temperature, solution c was added and reduced with strong stirring to obtain physical development nuclei of gold. Add Table 2 to this gold colloid solution as described above.
After adding the binder shown in , an appropriate amount of isoamyl-n-decylsulfosuccinic acid sodium salt was added as a coating aid to prepare the coating solution. The results of the printing test for the above samples are listed in Table 2 below.

[Table] As is clear from the results in Table 1 above, the physical development nucleus layer contains carboxymethyl cellulose with a degree of polymerization of 700 or less, and the silver halide emulsion layer contains fine grain powder with an average grain size of 1 μ to 10 μ. In the lithographic printing material sample according to the present invention, after preparing physical development nuclei,
It was found that the physical development nucleus layer to which a binder was added also provided excellent ink receptivity and reduced background smearing of printed matter. Effects of the Invention The lithographic printing material having a silver halide emulsion layer and a physical development nucleus layer according to the present invention not only has excellent ink receptivity, but also has low background smudge, making it possible to obtain good printed matter.

Claims (1)

[Claims] 1. A lithographic printing material using a silver salt diffusion transfer method having a silver halide emulsion layer and a physical development nucleus layer in order from the support side, wherein the silver halide emulsion layer contains fine grain powder with an average grain size of 1 μ to 10 μ. ,
A lithographic printing material characterized in that the binder of the physical development nucleus layer contains carboxymethyl cellulose having a degree of polymerization of 700 or less.