JP3372391B2 - Plate surface treatment liquid for lithographic printing plates - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the processing of a photosensitive lithographic printing plate using an aluminum plate as a support, and more particularly to the processing of a lithographic printing plate using a silver complex salt diffusion transfer method. Things. [0002] A lithographic printing plate using the silver complex salt diffusion transfer method (DTR method) is described in "Photographic Silver" published by Focal Press, London New York (1972), by Andrelot and Edith Weide. Halide Diffusion Processes ", pages 101-130, some examples are described. As described therein, a lithographic printing plate using the DTR method includes a two-sheet type in which a transfer material and an image receiving material are separated, or a monolith in which they are provided on a single support. Two types of sheet type are known.
Two-sheet type lithographic printing plates are disclosed in
It is described in detail in Japanese Patent No. 58844. For the mono sheet type, see JP 4830562, JP 51-15765,
It is described in detail in respective gazettes such as JP-A-51-111103 and JP-A-52-150105. [0004] A lithographic printing plate using paper as a support is difficult to print with high quality including printing durability due to plate elongation during printing and penetration of moisture. A film support is used for the purpose of improving these problems and improving printing performance. For example, a cellulose acetate film, a polyvinyl acetal film, a polystyrene film, a polypropylene film, a polyethylene terephthalate film, or a composite film obtained by coating a polyester, polypropylene, or polystyrene film with a polyethylene film can be used as the support. [0005] However, lithographic printing plates using a film as a support are improved in terms of plate elongation and moisture penetration, as compared with paper-based printing plates, but they have improved printing durability, water retention and printing. The problem remains in terms of the ability to hang the plate on the machine. In order to solve the above-mentioned various problems of the lithographic printing plate using a paper or a film as a support, a lithographic printing plate of a silver salt type using a metal, particularly an aluminum plate as a support has been known. JP-A-57-118244, JP-A-57-158844
And JP-A-62-260491, JP-A-3-116151, and JP-A-4-82295. JP-A-63-260491, JP-A-3-116151,
No. 4-822295 and the like, a roughened and anodized aluminum plate is used as a support, a physical development nucleus is supported thereon, and a photosensitive silver halide emulsion layer is further provided thereon. A lithographic printing plate utilizing the DTR method as a monosheet type is described in detail. According to the method, the lithographic printing plate is subjected to image exposure and DTR development, and then the silver halide emulsion layer is removed by washing with warm water to prepare a printing plate. It is described that the surface on which an image has been formed is subjected to plate surface treatment for increasing the hydrophilicity of the non-image portion and increasing the lipophilicity of the image silver. However, the plate surface treatment liquid described in JP-A-63-260491 has an unpleasant odor due to the addition of the enzyme, and has a particularly high enzyme activity at a practical processing temperature of 30 ° C. to 40 ° C. Poor stability over time, and there was a problem in liquid stability and persistence of enzyme activity. Also, JP-A-3-116151, 4-
The plate surface treating solution described in Examples such as 282295 has a strong plate surface protecting effect, but not only increases the hydrophilicity of the aluminum surface but also hydrophilizes the image area, has poor ink receptivity, and JP-A-3-116151. However, the photosensitive materials described in JP-A-63-260491 and the like having no intermediate layer are not sufficient in terms of ink acceptability and plate aging. Was. JP-A-48-45305, 54
No.-83502, No.57-29046 Plate processing solutions for plate processing of photosensitive printing materials and the like having non-image areas of gelatin mainly have the function of increasing the hydrophilicity of gelatin in non-image areas. I have. When these plate surface treatment liquids are used in a printing plate having a roughened and anodized aluminum plate as a support, which is the object of the present invention, the hydrophilicity of the image area is also increased and sufficient for ink receptivity. No significant effect was observed. SUMMARY OF THE INVENTION It is an object of the present invention to provide a roughened and anodized aluminum support which is the object of the present invention, a physical development nucleus layer thereon and a photosensitive silver halide photograph. An object of the present invention is to solve the above-mentioned problems in a lithographic printing plate having an emulsion layer and to provide a plate surface treating solution for a lithographic printing plate excellent in ink acceptability and liquid stability at the start of printing. [0010] It is an object of the present invention to provide a lithographic plate having a roughened and anodized aluminum support and having thereon a physical development nucleus layer and a photosensitive silver halide photographic emulsion layer. This was achieved by treating the printing plate with a plate surface treatment solution containing at least one polystyrene sulfonate having an average molecular weight of 20,000 or less, preferably 1,000 to 20,000. In the lithographic printing plate of the present invention, the image silver formed by development is not a composition of silver alone, but adsorbs a hydrophilic binder contained in a physical development nucleus or a photosensitive emulsion on the surface. In order to increase the ink affinity of the silver image obtained by the development process, not only silver but also a hydrophilic binder component existing on the surface has a lipophilic effect. Based on the idea that the surface of the aluminum part needs to maintain appropriate hydrophilicity, and contains a mercapto group, which is generally used for making the image silver lipophilic, in terms of the stability of the plate surface treatment solution. Based on the idea that stabilization by increasing the compatibility of an organic compound with an aqueous solution is indispensable, the present inventors have conducted intensive studies. As a result, in the lithographic printing plate having a roughened and anodized aluminum support and a physical development nucleus layer and a photosensitive silver halide photographic emulsion layer thereon, the average molecular weight is 20,000 or less, Preferably, by treating with a plate surface treating solution containing at least one kind of polystyrene sulfonate having a molecular weight of 1,000 or more and 20,000 or less, transfer silver excellent in ink receptivity is produced, and sufficient hydrophilicity is provided in the non-image area. The present invention has been found to produce a plate surface treatment liquid having excellent solution stability and especially stability over time. That is, the lithographic printing plate of the present invention using a roughened and anodized aluminum plate is formed around a physical development nucleus in which image silver is in contact with the aluminum surface, and has a continuous dense lipophilic property. A layer is formed and joined to the aluminum plate surface.
However, during the washing and removal of the photosensitive emulsion layer after development, the physical development nuclei and the hydrophilic binder in the emulsion remain on and adhere to the image silver surface, thereby inhibiting the lipophilicity of the image silver and causing printability, especially ink acceptability. This was the cause of the decline. Therefore, removal of the hydrophilic binder or lipophilicity has been required to improve ink receptivity. As a result of intensive studies for this purpose, when a polystyrene sulfonate is added to the plate surface treatment solution, a high molecular compound having an average molecular weight of 20,000 or more has a weak cleaning action and a strong adsorption action, and thus has poor binder releasability. , Does not promote the adsorption of the mercapto compound, which is an ink-riding aid to image silver, and has a weak effect on ink receptivity. However, when an average molecular weight of 20,000 or less is used, it has a moderate affinity with the hydrophilic binder. There is a strong washing action that improves the releasability of the binder from the image silver surface, adsorbs to the binder surface to bring about a surface activity, reduces the hydrophilicity of the binder gel, and reduces the adsorption of the mercapto compound to the silver image area. It has been found that the lipophilicity of image silver is increased by the effect of acceleration, and as a result, ink receptivity is improved. Furthermore, compared to other general surfactants, the high dispersing power improves the stability of organic compounds containing a mercapto group in the plate surface treatment solution, and provides a plate surface treatment excellent in ink receptivity and liquid stability. It has been found that a liquid can be prepared. The polystyrene sulfonate of the plate surface treatment solution of the present invention has a molecular weight of 20,000 or less, preferably 1,000 to 20,000, and may be used alone or in combination of two or more having different molecular weights. Is also good.
Further, the amount added to the plate surface treatment solution is different depending on the composition and type of the protective silver halide colloid of the photosensitive lithographic printing plate, but is preferably 5 g / L or more and 200 g / L or less, and more preferably 10 g / L or less.
It is more preferably from g / L to 100 g / L. The plate surface treating solution of the present invention can be used in any case between development and printing. Specifically, when peeling the emulsion layer by washing with water,
The plate surface treatment solution of the present invention may be used as an undiluted solution or may be used after diluting the plate surface after peeling the emulsion layer by washing with water.
Alternatively, it may be used undried, may be used as a plate surface protective solution, may be used together with a gum solution, and may be used as an etch solution before printing. It can also be used for various printing failures during printing. The plate surface treatment solution of the present invention may contain a known buffering salt such as phosphate, carbonate, citrate, nitrate, nitrite and the like, and a thickener such as carboxymethylcellulose. Hydroxymethylcellulose or hydrophilic polymer compounds such as polyvinyl alcohol, gum arabic, hydroxyethylcellulose, polyacrylic acid and the like can be contained alone or in combination of two or more. Anionic, cationic, nonionic and amphoteric surfactants can be added as surfactants. In the plate surface treatment solution of the present invention, it is necessary to use an organic compound having a mercapto group or a thione group for the purpose of promoting the ink receptivity of image silver. Tokiko Sho48
JP-A-29723 and JP-A-58-127928 disclose organic compounds having a mercapto group or a thione group. Basically, it has a structure consisting of a mercapto group or a thione group and a lipophilic group. Specific examples of such compounds include 2-mercapto-4-phenylimidazole and 2-mercapto-1
-Benzylimidazole, 2-mercapto-benzimidazole, 1-ethyl-2-mercapto-benzimidazole, 2-mercapto-1-butyl-benzimidazole, 1,3-diethyl-benzimidazoline-2-thione, 1,3- Dibenzyl-imidazolidin-2-thione, 2,2'-dimercapto-1,1'-decamethylene-diimidazoline, 2-mercapto-4-phenylthiazole, 2-mercapto-benzothiazole, 2-mercaptonaphthothiazole, 3- Ethyl-benzothiazoline-2-thione, 3-dodecyl-benzothiazoline-2
-Thione, 2-mercapto-4,5-diphenyloxazole, 2-mercaptobenzoxazole, 3-pentyl-benzoxazoline-2-thione, 1-phenyl-3-methylpyrazolin-5-thione, 3-mercapto-4-allyl -5-pentadecyl-1,2,4-triazole, 3-mercapto-5-nonyl-1,2,4-triazole, 3-mercapto-4-acetamido-5-heptyl-1,2,4-triazole, -Mercapto-
4-amino-5-heptadecyl-1,2,4-triazole, 2-mercapto-5-phenyl-1,3,4-thiadiazole, 2-mercapto-5-phenyl-1,
3,4-thiadiazole, 2-mercapto-5-n-heptyl-oxathiazole, 2-mercapto-5-phenyl-1,3,4-oxadiazole, 2-heptadecyl-5-phenyl-1,3,4 -Oxadiazole, 5
-Mercapto-1-phenyl-tetrazole, 2-mercapto-5-nitropyridine, 1-methyl-quinoline-
2 (1H) -thione, 2-mercapto-4-hydroxy-6-pentadecylpyridine, 3-mercapto-4-methyl-6-phenyl-pyridazine, 2-mercapto-
5,6-diphenyl-pyrazine, 2-mercapto-4,
6-diphenyl-1,3,5-triazine, 2-amino-4-mercapto-6-benzyl-1,3,5-triazine, 1,5-dimercapto-3,7-diphenyl-S
-Triazolino [1,2-a] -S-triazoline and the like, but are not limited thereto. Compounds selected therefrom can be contained alone or in combination of two or more. The thickness of the anodized layer of the roughened and anodized aluminum plate used in the present invention is about 0.3 to 3.00.
The range of μm is preferred. It is preferable to perform desmutting before or immediately after the anodizing treatment. That is, the roughened aluminum substrate is reduced to 10 to 50%
By treating with hot sulfuric acid (40-60 ° C) or a dilute alkali (such as sodium hydroxide), the smut adhered to the surface is removed. After the anodic oxidation treatment, a post-treatment can be performed if necessary. For example, UK Patent No.
The method of immersion treatment in an aqueous solution of polyvinylphosphonic acid disclosed in 1,230,447 is used. If necessary, an undercoat layer of a hydrophilic polymer can be provided, but is selected depending on the properties of the photosensitive layer provided thereon. The physical development nuclei of the physical development nucleus layer used in the present invention may be those used in a known silver complex salt diffusion transfer method. For example, colloids such as gold and silver, and water-soluble salts such as palladium and zinc may be used. Metal sulfide mixed with sulfide can be used. Various hydrophilic colloid compounds other than gelatin as protective colloids, for example, polyvinylpyrrolidone, various starches, albumin, polyvinyl alcohol, gum arabic, hydroxyethyl cellulose, hydroxyacrylic acid, etc., alone or in combination of two or more hydrophilic polymer compounds Can be used. For details and methods of preparation, see Focal Press, London, for example.
See "Photographic Silver Halide Diffusion Processes," published by Andre Lott and Edith Weide, New York (1972). In the photosensitive silver halide emulsion layer of the printing plate of the present invention, various hydrophilic colloid compounds can be used as hydrophilic protective colloids. That is, acid-treated gelatin, alkali-treated gelatin, gelatin derivatives, various gelatins such as grafted gelatin can be used, polyvinylpyrrolidone, various starches, albumin, polyvinyl alcohol, gum arabic, hydroxyethyl cellulose,
A hydrophilic polymer compound such as polyacrylic acid can be contained alone or in combination of two or more. As the hydrophilic colloid used, gelatin, a gelatin derivative, polyvinyl alcohol, polyvinylpyrrolidone and the like are more preferable, but substantially no hardener is used in order to facilitate release of the hydrophilic colloid layer after physical development. It is desirable to use a hydrophilic colloid layer. The types of photosensitive silver halide emulsion used in the present invention include silver chloride, silver bromide, and silver halide commonly used.
It is selected from silver iodide, silver chlorobromide, silver chloroiodobromide, silver iodobromide and the like. The emulsion type may be either a negative type or a positive type. These silver halide emulsions can be chemically or spectrally sensitized as necessary. The silver content of the photosensitive silver halide photographic emulsion coated on the aluminum plate of the lithographic printing plate used in the present invention has a known range as in the case of ordinary photographic emulsions, and the silver / gel ratio is the same as that of ordinary photographic emulsions. There is a known range for keeping the function of the dispersion stability of the silver halide contained in the protective colloid as well, but when coated on an aluminum plate that has been subjected to the above-mentioned surface treatment,
Silver to reduce corrosion by surface adsorption of silver halide grains
The ratio of silver / silver contained in the emulsion must be kept at an appropriate level to prevent direct contact between the silver halide particles in the protective colloid and the surface, to improve image quality, and to reduce manufacturing costs. The ratio of the protective colloid needs to be in an appropriate range. The developing solution used in the present invention is preferably a developing agent, for example, polyhydroxybenzenes or 3-pyrazolidinones. These agents are used in a so-called main agent-incorporated form contained in the plate material constituting layer. Is also good. Examples of the alkaline substance include known potassium hydroxide, sodium hydroxide, lithium hydroxide, potassium phosphate tribasic, potassium phosphate dibasic, sodium phosphate tribasic, sodium phosphate dibasic, ammonium phosphate tribasic, Ammonium diphosphate, sodium bicarbonate, sodium carbonate, potassium carbonate, ammonium carbonate, sodium silicate, potassium silicate, lithium silicate, sodium orthosilicate (SiO ₂ /
2Na ₂ O), sodium metasilicate _{(SiO 2 / Na 2 O)} , sodium disilicate _{(2SiO 2 / Na 2 O)} , sodium trisilicate (3SiO ₂ / N
a ₂ O), tetrasodium silicate _{(4SiO 2 / Na 2 O)} , inorganic alkali agents such as potassium dichromate potassium silicate potassium hydrogen or tetra silicate metasilicate, or an amine compound, a preservative, for example, sulfite Potassium, sodium sulfite, sodium bisulfite, potassium isobisulfite, thickeners such as carboxymethylcellulose, hydroxymethylcellulose, antifoggants such as potassium bromide, colorants such as 1-phenyl-5-mercaptotetrazole,
A development modifier, for example, an additive such as a polyoxyalkylene compound can be included. The pH of the developer is usually about 10 to 14, preferably about 12 to 14, but the pretreatment (for example, anodizing) of the aluminum support of the lithographic printing plate to be used, the photographic element,
It depends on the desired image, the type and amount of various compounds in the developer, the development conditions, and the like. Wash-off for removing the gelatin layer can be performed by rinsing with running water at a temperature of about 20 to 30 ° C. Of course, as described above, the treatment may be performed using the plate surface treatment solution of the present invention having the same water temperature. EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples.
Of course, it is not limited to these. Example 1 An aluminum plate having a thickness of 0.30 mm was degreased with a 4% aqueous sodium hydroxide solution, and then subjected to an alternating current of 10 V in an approximately 1% aqueous hydrochloric acid solution for approximately 20 minutes. Immediately, anodization was performed with 20% by weight of sulfuric acid at a current density of 1 A / dm ² for 5 minutes, followed by washing with water and drying to prepare an anodized aluminum plate on the surface. A physical development nucleus was coated on an aluminum support.
Further, the dried photosensitive silver halide emulsion layer was coated and dried to prepare a photosensitive lithographic printing plate. After the lithographic printing plate thus obtained was subjected to image exposure, it was developed with the diffusion transfer developer described in Example 1 of JP-A-4-82295, and then gelatin was immediately run in running water. The layer was washed off (washed off). Thereafter, gelatinous degrading enzyme (trypsin) and polystyrene sulfonate having various average molecular weights were added to the formulations shown in Table 1 as undried, as shown in Table 2, to prepare a plate surface treatment solution, coated with absorbent cotton or the like, dried and printed. A plate was made. The lithographic printing plate was applied to a printing machine AB Dick 350CD (trademark of offset printing machine manufactured by ABDick) to evaluate ink receptivity. The ink receptivity was evaluated based on the number of printed sheets until a printed material having a good image density was obtained by simultaneously starting paper feeding while bringing the ink roller into contact with the plate surface. Table 2 shows the results. Each treatment solution was aged and the ink receptivity was similarly evaluated. The liquid stability was measured as follows. The plate surface treatment liquid shown in Table 2 was forcibly aged under the conditions shown in Table 3 and the liquid stability was visually evaluated. Table 3 shows the results. The liquid properties were determined as follows.・ ・ ・: No change. Δ: cloudy. ×: precipitation, aggregation. [Table 1] [Table 2] [Table 3] According to the present invention, it is possible to obtain a lithographic printing plate surface treatment liquid having good ink receptivity and extremely high liquid stability.

Claims (1)

(57) Claims 1. Plate processing of a lithographic printing plate having a roughened and anodized aluminum support and having thereon a physical development nucleus layer and a photosensitive silver halide photographic emulsion layer In the liquid
A plate surface treatment solution, wherein the plate surface treatment solution contains at least one kind of polystyrene sulfonate having an average molecular weight of 20,000 or less.