JPH08240918A - Plate making method for photosensitive planographic printing plate and processing device - Google Patents

Abstract

PURPOSE: To provide a plate making method and a processing device without producing any precipitate in a processing tank in the rinsing zone, causing the printing soiling and deteriorating the desensitizing power of the gum liquid even when many plates are processed in the plate making method and device in which a photosensitive planographic printing plate is developed, coated with a gum, and corrected, then the printing plate is subjected again to a gum coating process by a reentry gum coating mechanism of a processing device having with a developing zone, rinsing zone and reentry gum coating mechanism. CONSTITUTION: After a photosensitive planographic printing plate is developed, coated with a gum and corrected, the plate is again subjected to a gum coating process by a reentry gum coating mechanism (C) of a processing device having with a developing zone (A), rinsing zone B1 , B2 and reentry gum coating mechanism (C). When the plate is coated with a gum by the reentry gum coating mechanism (C), a gum liquid which can be repeatedly used is supplied to the plate surface of the photosensitive planographic printing plate without passing the plate through the rinsing zone B1 , B2 , and then a replenishment gum liquid not used is supplied.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for making a photosensitive lithographic printing plate and a processing apparatus used in the plate making method. More specifically, it is a photosensitive material obtained by subjecting an image-exposed photosensitive lithographic printing plate to development processing and gumming. The present invention relates to a method for making a photosensitive lithographic printing plate, which comprises regumming the photosensitive lithographic printing plate again by a reentry gumming mechanism, and an apparatus used for the method.

[0002]

2. Description of the Related Art In the plate making of a photosensitive lithographic printing plate, after the imagewise exposed photosensitive lithographic printing plate is subjected to a developing treatment and a gumming treatment, necessary treatments such as correction on the plate surface are carried out.
Since the gum on this plate is removed, generally, as disclosed in U.S. Pat.No. 4,464,035, a lithographic printing plate is inserted from the middle of the processing zone to perform gumming (hereinafter referred to as "reentry It is called "gumming"). However, according to the apparatus disclosed in the above U.S. patent specification, this re-entry gumming is performed by inserting the gum from the water washing section, and thus scraps generated during necessary processing such as correction of the plate surface are performed. There is a case where gumming is carried out while the ink is still attached to the plate surface, and this gumming treatment cannot be performed in a desirable state.

In order to solve this problem, a method of treating a photosensitive lithographic printing plate with a rinse liquid at the time of reentry and then gumming treatment, and further, a second gumming treatment in JP-A-1-166992. Before carrying out, a method of rinsing the photosensitive lithographic printing plate with water or a rinsing liquid in at least two steps is disclosed.

By the way, the erasing liquid used in the erasing treatment carried out after the development and gumming treatment contains an acid. Further, a developing solution component and a photosensitive layer component dissolved in the developing solution are carried from the developing tank into the washing tank and the rinsing tank. For this reason, if the lithographic printing plate that has been subjected to the erasing treatment and the erasing liquid adheres to the plate surface is subjected to the second gumming after the washing or rinsing treatment, the washing water that becomes alkaline by bringing it from the developing tank or The rinse solution is neutralized by the acid in the erasing solution, the components of the photosensitive layer brought in together with the developing solution are deposited as insoluble matter, and gumming is performed while it is attached to the plate surface, and gumming treatment is not performed in a desirable state. , It may cause print stains or clog the shower. Further, the photosensitive layer components deposited in the water washing tank or the rinse tank are brought into the gumming tank, and the desensitizing power of the gum solution is reduced.

[0005]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to correct a lithographic printing plate which has been developed and gummed, and then apply the lithographic printing plate to a developing section, a rinse section and a reentry gumming mechanism. When performing reentry gumming with a processing device that has at least, even if a large number of plates are processed, deposits do not occur in the washing tank or rinsing tank, and printing stains and desensitizing power of gum solution are reduced. An object of the present invention is to provide a plate-making method that does not cause the problem and a processing apparatus used for the method.

[0006]

The constitution of the present invention for achieving the above object of the present invention is as follows.

After the photosensitive lithographic printing plate which has been subjected to the development processing and gumming is corrected, the gumming is performed again by the reentry gumming mechanism of the processor having the developing section, the rinse section and the reentry gumming mechanism. In the plate making method of a lithographic printing plate, during gumming by the reentry gumming mechanism, a gum solution that is repeatedly used is supplied to the plate surface of the photosensitive lithographic printing plate without passing through the rinse portion, and then an unused replenishment gum A method for making a photosensitive lithographic printing plate, which comprises supplying a liquid.

The photosensitive lithographic printing plate is provided with a developing section, a rinsing section,
A processing device for a photosensitive lithographic printing plate having a means for processing by passing through a reentry gum drawing part, wherein the reentry gum drawing part does not pass the photosensitive lithographic printing plate over the rinsing part Means for repeatedly supplying the gum liquid, means for supplying the gum liquid by the means and then supplying the unused gum liquid to the plate surface through a coating roller, and the unused gum liquid supplied to the plate surface And a means for replenishing the surplus liquid as a replenishing liquid for the gum liquid used repeatedly as described above.

The present invention will be described in detail below.

In the method of the present invention, a gum that is repeatedly used and a fresh gum that is supplied to the plate surface and is used as a replenisher for the gum solution that is repeatedly used has a water-soluble polymer compound and water as essential components. A liquid containing an acid, a surfactant, a water-soluble salt, a lipophilic substance, a wetting agent, an organic solvent, an antiseptic, an antifungal agent and the like can be used if necessary.

The water-soluble polymer compound includes natural polymers, semi-natural products, and synthetic products. Natural polymers include cane starch, potato starch, tapioca starch,
Wheat starch and starches such as corn starch, carrageenan, laminaran, sea sow mannan, fungus, Irish moss, those obtained from algae such as agar and sodium alginate, trolloaoi, mannan, quince seed, pectil, tragacanth gum, karaya gum, xanthine gum, Guarbingham, Locust Bingham,
Vegetable mucilages such as gum arabic, kaylop gum and benzoin gum, homopolysaccharides such as dextran, glucan and levan, and microbial mucilages such as heteropolysaccharides such as succinoglucan and xanthan gum, glue, gelatin, protein of casein and collagen sugar, etc. Is mentioned. Semi-natural products (semi-synthetic products) include propylene glycol alginate, viscose, methylcellulose, ethylcellulose, methylethylcellulose, hydroxyethylcellulose, carboxycellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, hydroxypropylethylcellulose and hydroxypropylmethylcellulose phthalate. Examples include fibrin derivatives such as and processed starch. The processed starch is white dextrin, roasted starch such as yellow dextrin and British gum, enzyme-modified dextrin such as enzyme dextrin and Schardinger dextrin, and fermented starch shown in solubilized starch,
Fermented starch, modified pregelatinized starch and non-denatured pregelatinized starch shown in dialdehyde starch,
Esterified starches such as phosphate starch, fatty starch, starch sulfate, starch nitrate, starch xanthate and starch carbamic acid, carboxyalkyl starch, hydroxyalkyl starch, sulfoalkyl starch, cyanoethyl starch, allyl starch, benzyl starch, carbamyl ethyl. Etherified starch, such as starch and dialkylamialkyl starch,
Crosslinked starch such as methylol crosslinked starch, hydroxyalkyl crosslinked starch, phosphoric acid crosslinked starch and dicarboxylic acid crosslinked starch, starch polyacrylamide copolymer, starch polyacrylic acid copolymer, starch polyvinyl acetate copolymer, starch polyacrylonitrile copolymer Examples thereof include polymers, cationic starch polyacrylic acid ester copolymers, cationic acid starch vinyl polymer copolymers, starch polystyrene maleic acid copolymers and starch graft copolymers such as starch polyethylene oxide copolymers. Synthetic products include polyvinyl alcohol other than partially acetalized polyvinyl alcohol, allyl-modified polyvinyl alcohol, polyvinyl methyl ether, polyvinyl ethyl ether, polyvinyl isobutyl ether and other modified polyvinyl alcohol,
Sodium polyacrylate, partially saponified polyacrylic acid ester, partially saponified polyacrylic acid ester copolymer, polyacrylic acid derivative and polymethacrylic acid derivative such as polymethacrylic acid salt and polyacrylic amide, polyethylene glycol, polyethylene oxide ,
Examples thereof include polyvinylpyrrolidone, a copolymer of polyvinylpyrrolidone and vinyl acetate, a carboxyvinyl polymer, a styrene maleic acid copolymer, and a styrene crotonic acid copolymer. Among these, those obtained from algae, vegetable mucilages, fibrin derivatives, modified starches, propylene glycol alginate and synthetic products are preferably used because they have good film forming properties on printing plates. More preferably sodium alginate, propylene glycol alginate, tragacanth gum, locust bin gum, guar gum, gum arabic, methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl methyl cellulose, carboxymethyl cellulose, roasted starch, oxygen-modified dextrin, oxidized starch, acid-decomposed starch, They are alfa starch, polyethylene glycol, polyvinyl alcohol, modified polyvinyl alcohol, polyacrylic acid derivative, polymethacrylic acid derivative, polyethylene oxide, and polyvinylpyrrolidone. Vegetable mucilages, fibrin derivatives and processed starches are preferably used because the emulsion has a strong protective colloid property. Roasted starch,
Enzyme-modified dextrin, oxidized starch, acid-decomposed starch and pregelatinized starch are preferably used because they do not reduce the sensitivity of the image area. The fibrin derivative is preferable because it has high emulsion stability due to the thickening effect. Carboxymethyl cellulose, gum arabic, tragacanth gum, locust bingham and guar bingham are preferred because they have a high non-sensitivity in the non-image area. Among them, gum arabic is preferable because it has a very high nonsensitivity in the non-image area. These water-soluble polymer compounds may be used alone or in combination of two or more. Particularly, two or more water-soluble high-solubilities selected from the group consisting of sodium alginate, propylene glycol alginate, gum arabic, dextrin, methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropylmethyl cellulose, carboxymethyl cellulose, polyethylene glycol, polyvinyl alcohol, and polyvinylpyrrolidone. When used in combination with molecular compounds, uniform film formation, prevention of deterioration of oil sensitivity in the image area,
It is preferable in terms of the protective colloid performance of the emulsion and the emulsion stability of the emulsion. Gum arabic, which is used in combination with one or more other water-soluble polymer compounds, is preferable because it can enhance the hydrophilicity and non-sensitivity of the non-image area without lowering the oil sensitivity of the image area, The ratio of gum arabic and the total amount of the other water-soluble polymer compound is preferably 4 to 1
It is 1:15, more preferably 2: 1 to 1: 8. Of these, the combination of gum arabic and dextrin is most preferably used. The water-soluble polymer is contained in a wide range of concentrations, but is generally about 1 to about 60% by weight, more preferably 2 to 40% by weight, and even more preferably 8 to 10% by weight based on the total weight of the gum solution.
Used at 25% by weight.

The gum solution used in the present invention preferably contains an acid. The acid to be contained is mainly used to adjust the pH of the desensitizing solution before use to an acidic region of pH, preferably pH 1 to 6, more preferably pH 2 to 4. For example, phosphoric acid, pyrophosphoric acid, polyphosphoric acid,
Inorganic acids such as sodium monophosphate, boric acid, hydrochloric acid, sulfuric acid, nitric acid, such as succinic acid, oxalic acid, citric acid, maleic acid,
Organic acids such as lactic acid, p-toluenesulfonic acid and benzenesulfonic acid can be used, and these can be used alone or in combination of two or more. Of these, phosphoric acid and succinic acid are particularly preferable.

The gum solution may further contain a water-soluble salt as a buffering agent. Suitable water-soluble salts include salts of inorganic acids such as molybdic acid, boric acid, nitric acid, sulfuric acid, phosphoric acid, polyphosphoric acid and acetic acid, oxalic acid, tartaric acid, benzoic acid, succinic acid,
Examples thereof include salts of organic acids such as citric acid, malic acid, lactic acid, tannic acid and p-toluenesulfonic acid. Preferred salts are water-soluble alkali metal salts and ammonium salts, particularly preferred are molybdate salts such as ammonium molybdate, nitrates such as potassium nitrate, sulfates, phosphates such as sodium phosphate, potassium tetrapolyphosphate, sodium trimetaphosphate and the like. Polyphosphate, oxalate such as sodium oxalate, tartrate such as potassium tartrate, succinate such as sodium succinate, and citrate such as ammonium citrate. Such water-soluble salts may be used alone or in combination of two or more, and the total amount of the salts is preferably about 10% by weight or less based on the total weight of the gum solution in terms of emulsion stability. More preferably 0.01 to 6% by weight
Used in the range of.

The gum solution used in the present invention may contain a surfactant. As such a surfactant,
Fatty acid salts, abithienates, hydroxyalkane sulfonates, alkane sulfonates, dialkylsulfosuccinates, linear alkylbenzene sulfonates, branched chain alkylbenzene sulfonates, alkylnaphthalene sulfonates, alkylphenoxypolyoxyethylenepropyl Sulfonates, polyoxyethylene alkylsulfophenyl ether salts, N-methyl-N
-Sodium oleyl taurine, N-alkylsulfosuccinic acid monoamide disodium salt, petroleum sulfonates, sulfated castor oil, sulfated cattle foot oil, sulfate ester salts of fatty acid alkyl esters, alkyl sulfate ester salts, polyoxyethylene alkyl ethers Sulfate ester salts, fatty acid monoglyceride sulfate ester salts, polyoxyethylene alkylphenyl ether sulfate ester salts, polyoxyethylene styrylphenyl ether sulfate ester salts, alkyl phosphate ester salts, polyoxyethylene alkyl ether phosphate ester salts, polyoxyethylene alkyl Phenyl ether phosphate ester salt, partially saponified styrene-maleic anhydride copolymer, partially saponified olefin-maleic anhydride copolymer, naphthalene Anionic surfactants such as rufonate formalin condensates, and polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene polystyryl phenyl ethers, polyoxyethylene polyoxypropylene alkyl ethers, glycerin fatty acid moieties Esters,
Sorbitan fatty acid partial ester, pentaerythritol fatty acid partial ester, propylene glycol monofatty acid ester, sucrose fatty acid partial ester, polyoxyethylene sorbitan fatty acid partial ester, polyoxyethylene sorbitol fatty acid partial ester, polyethylene glycol fatty acid ester, polyglycerin Fatty acid partial esters, polyoxyethylenated castor oil,
Polyoxyethylene glycerin fatty acid partial esters,
Nonionic surfactants such as fatty acid diethanolamides, N, N-bis-2-hydroxyalkylamines, polyoxyethylene alkylamines, triethanolamine fatty acid esters and trialkylamine oxides are preferred. These surfactants may be used alone or in combination of two or more, and may be used in an amount of about 0.01 to 1 in an aqueous solution.
It is used in an amount of 0% by weight, preferably 0.1 to 1% by weight.

The gum solution may further contain a lipophilic substance dissolved therein. Preferred lipophilic substances are lipophilic resins used as vehicles for lithographic printing inks. Specifically, phenol formaldehyde resin, cresol formaldehyde resin, novolak type phenol resin such as t-butylphenol formaldehyde resin, xylene resin obtained by condensation of phenol and xylene with formaldehyde, resin obtained by condensation of phenol and mesitylene with formaldehyde. Polyhydroxystyrene, brominated polyhydroxystyrene, cashew resin,
Partial esterification product of copolymer of styrene and maleic anhydride, melamine resin, alkyd resin, polyester resin,
Examples thereof include epoxy resins, rosins, modified rosins such as hydrogenated rosins and rosin esters, and petroleum resins such as Gilsonite. Among these, novolac type phenol resins, rosins and modified rosins are preferable. Other preferred lipophilic substances include plasticizers, fatty acids, fatty oils, waxes. Preferred plasticizers include, for example, dibutyl phthalate,
Diheptyl phthalate, di-n-octyl phthalate, di-
(2-ethylhexyl) phthalate, dinonyl phthalate,
Phthalic acid diesters such as didecyl phthalate, dilauryl phthalate, and butylbenzyl phthalate, such as dioctyl azelate, dioctyl adipate, dibutyl glycol adipate, dibutyl sebacate, di- (2-
Ethylhexyl) sebacate, aliphatic dibasic acid esters such as dioctyl sebacate, epoxidized triglycerides such as epoxidized soybean oil, such as tricresyl phosphate, trioctyl phosphate,
Included are phosphoric acid esters such as trischloroethyl phosphate, for example benzoic acid esters such as benzyl benzoate. Among these, particularly preferred are dioctyl adipate, dibutyl sebacate and dioctyl azelate, which are odorless and highly safe. Preferred fatty acids include caproic acid, enanthic acid, caprylic acid, pelarbic acid, capric acid, undecylic acid, lauric acid,
Tridecylic acid, myristic acid, pentadecylic acid, palmitic acid, heptadecyl acid, stearic acid, nonadecanoic acid, arachidic acid, behenic acid, lignoselenic acid, cerotic acid, heptacosanoic acid, montanic acid, melissic acid, laxeric acid, isovaleric acid, etc. Saturated fatty acids and acrylic acid, crotonic acid, isocrotonic acid, undecylenic acid, oleic acid,
There are unsaturated fatty acids such as elaidic acid, cetoleic acid, erucic acid, brassic acid, sorbic acid, linoleic acid, linolenic acid, arachidonic acid, propiolic acid, stearolic acid, siwasic acid, tariphosphoric acid and licanoic acid. Examples of preferable waxes include carnauba wax, beeswax, whale wax, insect white wax, wool wax, and serrata crow.

The gum solution may further contain a wetting agent. This makes it possible to improve the property that the hydrophilic component such as the water-soluble polymer compound of the gum solution appropriately spreads to the non-image area of the lithographic printing plate and the flexibility of the film. Preferred examples of such wetting agents are polyhydric alcohols, specifically ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butylene glycol, pentanediol, hexylene glycol, tetraethylene glycol, polyethylene glycol, dipropylene glycol. , Tripropylene glycol, glycerin, sorbitol, pentaerythritol and the like, and glycerin is particularly preferable. The wetting agent is used in the range of about 0.5 to about 10% by weight, more preferably 1 to 5% by weight, based on the total weight of the desensitizing agent of the present invention.

The gum solution may contain an organic solvent. Preferred organic solvents are sparingly water-soluble, for example, turpentine oil, xylene, toluene, benzene, n-heptane, solvent naphtha, kerosene, mineral spirits, petroleum fraction having a boiling point of about 120 to about 250 ° C., ketones such as cyclohexanone. , Halogenated hydrocarbons such as dichloroethylene, ethylene glycol monomethyl ether, ethylene glycol monophenyl ether, ethylene glycol monobutyl ether, ethylene glycol monoethyl ether and other ethylene glycol ethers. These solvents are used in the range of about 0.05 to about 10% by weight, more preferably 0.5 to 5% by weight, based on the total weight of the desensitizing solution.

The gum solution further contains preservatives such as sorbic acid and ethyl p-oxybenzoate, antifungal agents, propyl gallate,
It is preferable to add an antioxidant such as 2,6-di-t-butyl-4-ethylphenol or 2,6-di-t-butyl-4-methylphenol. Preservatives as these preservatives,
Although the preservation effect of the gum solution can be obtained by adding a small amount of the anti-treat agent and the antioxidant, it is preferably 0.001 to 5% by weight.

The gum solution used in the present invention may be an emulsion type gum solution, a suspension type gum solution, a non-emulsion type non-suspension type gum solution, etc., depending on the surfactant, lipophilic substance, etc. to be contained. It can be manufactured in any way. Further, in order to improve the preparation efficiency and the transportation efficiency of the gum solution, it is preferable to adopt a method in which the components are prepared at a high concentration and then diluted with water to a preferable concentration at the time of use.

In the present invention, the amount of gum solution used repeatedly is ^{20 to 200} per 1 m ² of the photosensitive lithographic printing plate.
ml is preferable, and the amount of unused gum solution is preferably 10 to 100 ml per 1 m ² of the photosensitive lithographic printing plate, and 20
~ 50 ml is more preferred.

The means for supplying the gum solution is a method for directly supplying the gum solution to the plate surface by a shower pipe that has been most commonly used in the past, through a roll or a rectifying means, for both the gum solution that is repeatedly used and the gum solution that has not been used. A desired supply means such as a supply method, a dipping method, a method of applying with a roller can be used, but a gum solution to be repeatedly used is preferably a method of directly supplying to the plate surface by a shower pipe, and an unused gum solution is A method of applying via a roller is preferable.

As the rinsing liquid used in the rinsing portion in the present invention, a commonly used liquid including known ones can be used. As the rinse liquid, water or JP-A-62-1
An aqueous solution containing a surfactant, an acid and a salt thereof, an antiseptic, an antifungal agent, an antioxidant, a lipophilic substance and the like disclosed in 36672 is preferably used. The rinsing part in the present invention may be composed of a plurality of parts, for example, a rinsing part with rinsing water and a rinsing part with a rinsing liquid containing a surfactant thereafter.

The photosensitive lithographic printing plate to which the invention is applied may be either a positive type or a negative type. Examples of the photosensitive lithographic printing plate include the photosensitive lithographic printing plates described in JP-A-62-58253. In addition, examples of the developer used in the processing method of the present invention include those used for developing the photosensitive lithographic printing plate. As a typical developing solution, in addition to alkali agents such as alkali metal silicates and alkali metal hydroxides, if necessary, nonionic, anionic, cationic or amphoteric surfactants, organic solvents, sulfites, aliphatic carboxylic acids , An aqueous alkaline developer containing an aromatic carboxylic acid or the like.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a processing apparatus of the present invention will be described with reference to the drawings. FIG. 1 is a view showing the schematic arrangement of a photosensitive lithographic printing plate processing apparatus according to this embodiment. In the processing apparatus 1 of this embodiment, the photosensitive lithographic printing plate 2 image-exposed by a printing apparatus (not shown) is developed by the processing apparatus 1 and then dried, and is also subjected to development processing and correction. There is a reentry portion D for inserting the plate 3 that is rubbed and gummed again into the gumming portion C that gums, so that the gumming portion C can perform gumming processing again. 3b
Is a photosensitive lithographic printing plate transport path, and 3a is a plate transport path for reentry gumming.

The processing apparatus 1 comprises a developing section A, a rinsing section B ₁ ,
B ₂ and a gumming portion C and a reentry portion D are provided, and the reentry portion D has an insertion table 4 for inserting a plate into the gumming portion C. 5 is a pair of conveying rollers, 6 is a brush roller, 7 is a counter roller, 8 is an application roller for applying an unused gum solution to the plate surface, 9 is a counter roller, and 11, 12, 13, and 14 are processing liquids. A processing liquid tank, 16a is a shower nozzle for supplying the processing liquid in the processing liquid tank 11 to the photosensitive lithographic printing plate, 16b is a shower nozzle for supplying the processing liquid in the processing liquid tank 12 to the photosensitive lithographic printing plate, and 16c is Shower nozzles for supplying the processing liquid in the processing liquid tank 13 to the photosensitive lithographic printing plate, and the processing liquid in each processing liquid tank is sent to the respective shower nozzles by a pump and piping not shown. In the processing section C, 20 is a shower nozzle for supplying the gum solution in the gum solution tank 14 to the photosensitive lithographic printing plate.
The gum solution therein is repeatedly circulated to the shower nozzle 20 by the pump 21 and supplied to the printing plate. The unused gum solution is put in the gum replenishing solution storage tank 22, and this gum solution is supplied from the shower nozzle 24 to the peripheral surface of the coating roller 8 by the pump 23, and the unused gum solution is applied to the plate surface via the coating roller 8. Is to be applied.
Excess liquid of the gum solution applied to the plate surface flows downward and serves as a replenisher for the gum solution in the gum solution tank 14.

In the processing apparatus of the present invention, it is preferable that the gum liquid application roller is made of rubber at the contact portion with the plate.
The rubber hardness is preferably 75 degrees or less. The rubber member used for the coating roller is made of rubber having elasticity, and its material (raw rubber) is natural rubber, synthetic natural rubber, styrene, butadiene rubber, butyl rubber, ethylene propylene rubber, chlorosulfonated polyethylene rubber, chloropropylene rubber. , Nitrile rubber,
Acrylic rubber, urethane rubber, silicone rubber, fluororubber and polysulfide rubber (organic polysulfide) are used. Generally, a plasticizer, a filler and the like are added to these raw rubbers to adjust the hardness, elasticity and strength. The chemical resistance of these rubber materials depends on the type of raw rubber and the type and amount of additives added to it.

The raw rubber preferable as the material for the rubber member used for the coating roll is one which has resistance to chemical treatment by itself and which can obtain preferable hardness and elasticity by adding as little plasticizer or filler as possible. In this sense, among the above-mentioned raw rubbers, fluororubber, butyl rubber and polysulfide rubber are preferable, and fluororubber is more preferable. Types of fluororubber include tetrafluoroethylene / propylene copolymer elastomer, tetrafluoroethylene / ethylene copolymer elastomer, vinylidene fluoride / perfluoropropylene copolymer elastomer, tetrafluoroeletin / perfluoromethyl vinyl ether copolymer elastomer, fluoro Silicone-based elastomers, fluorophosphazene-based elastomers, vinylidene fluoride / 1-hydropentafluoropropylene copolymer-based elastomers, and the like.
Particularly preferable among these are rubbers containing a vinylidene fluoride / perfluoropropylene copolymer elastomer as a main component.

Additives added to these raw rubbers include plasticizers, stabilizers, UV absorbers, antistatic agents, flame retardants, fillers, reinforcing agents, colorants, foaming agents, crosslinking agents, lubricants,
Examples include fragrances, plane agents and antiaging agents.

The rubber member used for the coating roll has a plasticizer content of 20% by weight or less and has a proper elasticity, and includes a phthalate ester type, an aliphatic dibasic acid ester type, and a phosphate ester. Plasticizers such as epoxy resins, epoxy resins, chlorinated paraffin resins and polyester resins are preferably used. For the cross-linking of the rubber member, vidroperoxide,
Peroxides such as dialkyl peroxides and diacyl peroxides, sulfur, zinc white and magnesium oxide are used.

The coating roller is 6 in the direction of the arrow shown in FIG.
It is preferable to rotate at 0 to 200 rpm. Further, the amount of gum liquid on the plate surface after passing through the coating roller is preferably 10 to 70 ml / m ² , and more preferably 20 to 40 m.
It is preferable to apply pressure to the coating roller so as to be 1 / m ² .

Next, the processing method of the present invention will be described more specifically by way of examples.

Example Using the processing apparatus shown in FIG. 1, a developing solution having the following composition, tap water, a rinse solution and a gum solution were prepared as a processing solution, and the processing tank 1
The developer was put in No. 1, the tap water was put in the processing tank 12, the rinse solution was put in the processing tank 13, and the gum solution was put in the processing tank 14 and the gum replenishing solution storage tank 22. The gum solution volume of the processing tank 14 was 10 liters.

Developer solution Potassium silicate (SiO ₂ : 26%, K ₂ O: 13.5%) 80 parts by weight 86% potassium hydroxide 40 parts by weight Water 326 parts by weight Rinsing solution Lauryl alcohol sulfate sodium salt 40 parts by weight 85% phosphoric acid 40 parts by weight water 1000 parts by weight gum solution carboxymethylcellulose sodium salt 0.45 parts by weight modified dextrin (Penon JE-66, manufactured by Nippon Starch Chemical Co., Ltd.) 9 parts by weight phosphoric acid (85%) 0.2 parts by weight Parts Polyethylene oxide (ethylene oxide average addition mole number 15) nonyl ether 0.1 parts by weight sodium di (2-ethylhexyl) sulfosuccinate 0.12 parts by weight water 90 parts by weight Positive-working photosensitive material imagewise exposed by such a processing apparatus Sex planographic printing plate KM-3 (Konica Corporation, 800 mm x 103)
(0 mm) was subjected to manual correction such as erasing, and then this plate was inserted from the reentry section D and gummed again. In the above treatment, the supply amount of the gum liquid to be recycled and reused was 10 l / min, and the supply amount of the unused gum liquid was 30 ml per 1 m ² of the photosensitive lithographic printing plate. When the above-mentioned photosensitive lithographic printing plate was subjected to 1000 plate processing under these conditions, printing was performed on the first 1st plate and the 1000th plate, and the first 1st plate and the 1000th plate were also stained. A beautiful printed matter with good ink receptivity was obtained.

Comparative Example The same experiment as in the above example was carried out except that the automatic developing machine described in JP-A-1-166992 was used as a processing device, and it was insoluble in the washing part and rinsing part after 500 plate processing. A substance was generated, and the gum solution in the gumming treatment part was also suspended. Further, when printing was performed using the obtained printing plate, a printed matter having a stain on the non-image area was generated.

[0035]

According to the present invention, after the photosensitive lithographic printing plate which has been developed and gummed is modified, the lithographic printing plate is processed by a processing device having a developing section, a rinsing section and a reentry gumming mechanism. When performing reentry gumming, a platemaking method that does not cause deposits in the washing tank or rinsing tank even if a large number of plates are processed, and does not cause deterioration of printing stains or desensitizing power of gum solution and A processing device is provided.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a processing apparatus of the present invention.

[Explanation of symbols]

A developing section B ₁ , B ₂ rinsing section C gumming section D entry section 4 insertion table 11, 12, 13, 14 processing solution tank 16a, 16b, 16c, 20, 24 shower nozzle 22 gum replenisher storage tank

Claims (2)

[Claims] 1. After correcting a photosensitive lithographic printing plate which has been subjected to development processing and gumming, gumming is performed again by the reentry gumming mechanism of a processing device having a developing section, a rinse section and a reentry gumming mechanism. In the plate making method of the photosensitive lithographic printing plate to be performed, during gumming by the reentry gumming mechanism, a gum solution that is repeatedly used is supplied to the plate surface of the photosensitive lithographic printing plate without passing through the rinse portion,
Next, a method for making a photosensitive lithographic printing plate comprising supplying an unused replenishment gum solution. 2. A photosensitive lithographic printing plate comprising a developing section, a rinsing section,
A processing device for a photosensitive lithographic printing plate having a means for processing by passing through a reentry gum drawing part, wherein the reentry gum drawing part does not pass the photosensitive lithographic printing plate over the rinsing part Means for repeatedly supplying the gum liquid, means for supplying the gum liquid by the means and then supplying the unused gum liquid to the plate surface through a coating roller, and the unused gum liquid supplied to the plate surface And a means for replenishing the surplus liquid as a replenishing liquid for the gum liquid used repeatedly as described above.