JPH11218935A - Treatment of photosensitive lithographic printing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a treating method of a photosensitive lithographic printing plate by which the finishing treatment for a photosensitive lithographic printing plate having an aluminum plate as a supporting body can be stably continued while suppressing production of insoluble scum in the finishing bath after the printing plate is developed with a developer containing nonreducing sugars and bases (except for silicates), and to provide a treating method of a photosensi tive lithographic printing plate to produce a lithographic printing plate without printing contamination or failure in ink deposition for a long time. SOLUTION: In the treating method of a photosensitive lithographic printing plate, a photosensitive lithographic printing plate having an aluminum plate as a support is exposed, developed with a developer containing nonreductive sugars and bases (except silicates), and then subjected to finishing treatment. In this process, the finishing liquid contains at least one kind of hydroxycarboxylic acid.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for processing a photosensitive lithographic printing plate, and more particularly to a method for processing a photosensitive lithographic printing plate suitable for long-term stable processing.

[0002]

2. Description of the Related Art Conventionally, a photosensitive lithographic printing plate widely used comprises an aluminum plate as a support, on which a photodegradable or photocurable photosensitive layer is provided. These photosensitive layers are solubilized in a developer by the actinic ray, and the latter become insoluble by the actinic light. Therefore, when this is developed, only the developer-soluble portion of the photosensitive layer is removed, and the surface of the support is exposed. Since the surface of the aluminum support is hydrophilic, a portion (non-development portion) where the surface of the support is exposed by development retains water and repels oil-based ink. on the other hand,
Area where the photosensitive layer was not removed by development (image area)
Is lipophilic and repels water and accepts ink.

As a developer for such a photosensitive lithographic printing plate, an alkaline aqueous solution has been generally used. Among them, aqueous silicate solutions such as sodium silicate and potassium silicate have been generally used. However, although silicates are stable in the alkaline region, they have the drawback that they are neutral and gel, insolubilize, and are only soluble in strong acids such as hydrofluoric acid when evaporated to dryness. Actually, there has been a problem that aluminum silicate adheres to the developing tank or the developing solution replenishment sensor and is difficult to clean, and silica gel is generated when neutralizing the waste liquid of the developing solution.

[0004] In order to solve such problems, attempts have been made to use an alkali agent other than silicate, and for example, a developer containing a non-reducing sugar and a base other than silicate has been proposed (Japanese Patent Application Laid-Open No. Hei 8 (1996)). -160631, JP-A-8-23
4447, JP-A-8-305039). According to the developer containing the non-reducing sugar and the base, the disadvantage caused by the developer containing the silicate is eliminated. on the other hand,
A developer containing a non-reducing sugar and a base other than silicate is more likely to attack the aluminum support of the photosensitive lithographic printing plate than a conventional developer comprising an alkali metal silicate, and has a larger elution amount of aluminum ions. When aluminum ions eluted during development are brought into the usually acidic finishing solution (a desensitizing solution containing a water-soluble resin or an aqueous solution containing a surfactant) by the plate being processed, insoluble residues (aluminum oxide) Occurs. After the insoluble residue is deposited on the transport roller, it adheres to the plate surface, causing printing stains and poor ink deposition. In addition, it precipitates even in the finishing liquid, causing clogging of filters and sprays, making long-term stable treatment impossible. This problem could not be satisfactorily solved even if the plate was washed with water after development and before finishing.

[0005]

SUMMARY OF THE INVENTION The present invention provides a finishing lithographic printing plate having an aluminum plate as a support, which is developed with a developer containing a non-reducing sugar and a base (excluding silicate). An object of the present invention is to provide a method for processing a photosensitive lithographic printing plate capable of suppressing generation of insoluble residue in a bath and maintaining stable processing. It is a further object of the present invention to provide a method for processing a photosensitive lithographic printing plate capable of producing a lithographic printing plate free from printing stains and defective ink deposition over a long period of time.

[0006]

Means for Solving the Problems The present inventors have made intensive studies to achieve the above object, and as a result, by adding oxycarboxylic acid to the finishing solution, the generation of insoluble residues in the finishing bath has been reduced. They have found that they can be suppressed, and have completed the present invention.
Therefore, the present invention relates to a method for preparing a photosensitive lithographic printing plate using an aluminum plate as a support, by exposing, a non-reducing sugar and a base (excluding silicate).
In a step of performing a finishing treatment after developing with a developing solution containing a developer, the finishing solution contains at least one oxycarboxylic acid. Here, the finishing treatment means a desensitization treatment or a rinsing treatment. The finishing liquid may be a desensitizing liquid containing a water-soluble resin or an aqueous solution containing a surfactant (hereinafter referred to as a rinsing liquid).

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The finishing solution used in the present invention will be described in detail below. Unless otherwise specified, the finishing liquid and the finishing replenisher are collectively referred to as a finishing liquid. Specific examples of the oxycarboxylic acid contained in the finishing solution include gluconic acid, glycolic acid, lactic acid, hydroacrylic acid, glyceric acid, tartronic acid, tartaric acid, citric acid, malic acid, and the like. Among them, citric acid, gluconic acid, malic acid and tartaric acid are preferred. The amount of oxycarboxylic acid added to the finishing solution depends on the amount of aluminum eluted into the developing solution and the amount of eluted aluminum brought into the finishing solution, but is generally 0.001 to 0.001 based on the total weight of the finishing solution. 2.0% by weight is suitable, and a more preferred range is 0.01 to 0.5% by weight. If the amount is less than 0.001% by weight, the generation of insoluble residue caused by aluminum cannot be sufficiently suppressed. On the other hand, when the content exceeds 2.0% by weight, the ink adhesion at the start of printing tends to decrease.

The finishing solution is generally free to be used in a pH range of 3 to 12, which is lower than that of the developing solution. p
In order to adjust H to 3 to 12, a mineral acid, an organic acid, an inorganic salt, or the like is generally added to the finishing solution and adjusted. The amount of addition is 0.01 to 2% by weight. For example, mineral acids include nitric acid, sulfuric acid, phosphoric acid, and metaphosphoric acid. Examples of the organic acid include acetic acid, oxalic acid, malonic acid, p-toluenesulfonic acid, levulinic acid, phytic acid, organic phosphonic acid, and amino acids such as glycine, α-alanine and β-alanine. Examples of the inorganic salt include magnesium nitrate, monobasic sodium phosphate, dibasic sodium phosphate, nickel sulfate, sodium hexametaphosphate, sodium tripolyphosphate and the like. At least one kind or two or more kinds of mineral acids, organic acids or inorganic salts may be used in combination.

When the finishing liquid used in the present invention is a rinsing liquid containing a surfactant, it contains a lipophilic substance, a preservative, a fungicide, an antifoaming agent, etc. in addition to the above-mentioned pH adjuster. Can be kept. Examples of the surfactant that is a main component of the rinsing liquid include an anionic surfactant, a cationic surfactant, an amphoteric surfactant, and a nonionic surfactant. Fatty acid salts as anionic surfactants,
Abietic acid salts, hydroxyalkanesulfonates, alkanesulfonates, α-olefinsulfonates, dialkylsulfosuccinates, alkyldiphenyletherdisulfonates, linear alkylbenzenesulfonates, branched-chain alkylbenzenesulfonates, alkylnaphthalenesulfones Acid salts, alkylphenoxypolyoxyethylenepropyl sulfonates,
Polyoxyethylene alkylsulfophenyl ether salts, N-methyl-N-oleyltaurine sodium,
N-alkylsulfosuccinic acid monoamide disodium salts,

Petroleum sulfonates, sulfated castor oil, sulfated tallow oil, sulfates of fatty acid alkyl esters, alkyl sulfates, polyoxyethylene alkyl ether sulfates, fatty acid monoglyceride sulfates, polyoxyethylene alkyl Phenyl ether sulfates, polyoxyethylene styryl phenyl ether sulfates, alkyl phosphates, polyoxyethylene alkyl ether phosphates, polyoxyethylene alkyl phenyl ether phosphates, styrene-maleic anhydride copolymer Examples include saponified compounds, partially saponified olefin-maleic anhydride copolymers, and naphthalene sulfonate formalin condensates. Among them, dialkyl sulfosuccinates, alkyl sulfates, alkyl naphthalene sulfonates and α-
Olefin sulfonates and alkyl diphenyl ether disulfonates are particularly preferably used. As the cationic surfactant, alkylamine salts, quaternary ammonium salts and the like are used.

As the amphoteric surfactant, alkyl carboxy betaines, alkyl imidazolines, alkyl amino carboxylic acids and the like are used. Nonionic surfactants include polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene polystyryl phenyl ether, polyoxyethylene polyoxypropylene alkyl ether, glycerin fatty acid partial esters, sorbitan fatty acid partial esters 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 ester ,

Polyoxyethylated castor oils, polyoxyethylene glycerin fatty acid partial esters, fatty acid diethanolamides, N, N-bis-2-hydroxyalkylamines, polyoxyethylene alkylamines, triethanolamine fatty acid esters, triethanolamine Examples include alkylamine oxide, a molecular weight of polypropylene glycol of 200 to 5,000, an addition product of trimethylolpropane, glycerin or sorbitol with polyoxyethylene or polyoxypropylene, and acetylene glycol. Also, fluorine-based and silicon-based nonionic surfactants can be used in the same manner. Two or more surfactants can be used in combination. The amount of use is not particularly limited, but a preferable range is 0.01 to 20% by weight based on the total weight of the rinsing liquid, and preferably 0.01 to 20% by weight.
05 to 10% by weight.

As the preservative used for the rinsing liquid, known substances used in the fields of fiber, wood processing, food, medicine, cosmetics, agrochemicals and the like can be used. For example, quaternary ammonium salts, monohydric phenol derivatives, dihydric phenol derivatives, polyhydric phenol derivatives, imidazole derivatives, pyrazolopyrimidine derivatives, monovalent naphthols, carbonates, sulfone derivatives, organic tin compounds, cyclopentane derivatives, phenyl derivatives , Phenol ether derivatives, phenol ester derivatives, hydroxylamine derivatives, nitrile derivatives, naphthalenes, pyrrole derivatives, quinoline derivatives, benzothiazole derivatives, secondary amines, 1,3,5 triazine derivatives, thiadiazole derivatives, anilide derivatives, pyrrole derivatives , Halogen derivatives, dihydric alcohol derivatives, dithiols, cyanic acid derivatives, thiocarbamic acid derivatives, diamine derivatives, isothiazole derivatives, monohydric alcohols, saturated aldehydes, Sum monocarboxylic acids, saturated ethers, unsaturated ethers,

Lactones, amino acid derivatives, hydantoin, cyanuric acid derivatives, guanidine derivatives, pyridine derivatives, saturated monocarboxylic acids, benzenecarboxylic acid derivatives, hydroxycarboxylic acid derivatives, biphenyl, hydroxamic acid derivatives, aromatic alcohols, halogenophenol derivatives, Benzenecarboxylic acid derivative, mercaptocarboxylic acid derivative, quaternary ammonium salt derivative, triphenylmethane derivative, hinokitiol, furan derivative, benzofuran derivative, acridine derivative, isoquinoline derivative, arsine derivative, thiocarbamic acid derivative, phosphate ester, halogenobenzene Derivatives, quinone derivatives,
Benzenesulfonic acid derivative, monoamine derivative, organic phosphate, piperazine derivative, phenazine derivative,
Known preservatives among pyrimidine derivatives, thiophanate derivatives, imidazoline derivatives, isoxazole derivatives, ammonium salt derivatives and the like can be used.

As particularly preferred preservatives, salts of pyridinethiol-1-oxide, salicylic acid and salts thereof,
1,3,5-trishydroxyethylhexahydro-S
-Triazine, 1,3,5-trishydroxymethylhexahydro-S-triazine, 1,2-benzisothiazolin-3-one, 5-chloro-2-methyl-4-isothiazolin-3-one, 2-bromo- 2-nitro-1,
3-propanediol is exemplified. A preferable addition amount is an amount stably exerting an effect on bacteria, mold, yeast and the like, and varies depending on the kind of bacteria, mold and yeast. 01-4% by weight
Is preferable, and two or more preservatives are preferably used in combination so as to be effective against various molds and bacteria.

[0016] The rinsing liquid can also contain a lipophilic substance. As a result, the image area of the lithographic printing plate becomes more oil-sensitive, and the development ink is used (emulsion type ink (usually used to make the image easier to see after development and to increase the oil sensitivity of the image and maintain it). Black)
Not only on the image) but also after the treatment with the aqueous solution, a plate surface protective agent treatment is performed.
A decrease in the oil sensitivity of the image area can be strongly suppressed. Preferred lipophilic substances include, for example, oleic acid, lanolinic acid,
Organic carboxylic acids having 5 to 25 carbon atoms, such as valeric acid, nonylic acid, capric acid, myristic acid, and palmitic acid, and castor oil are included. These lipophilic substances can be used alone or in combination of two or more. The lipophilic substance to be contained in the rinsing liquid is 0.005 to 10% by weight, more preferably 0.05 to 5% by weight, based on the total weight thereof.
It is in the range of 5% by weight. An antifoaming agent can be added, and a silicone antifoaming agent is particularly preferable. Among them, an emulsified dispersion type and a solubilized type can be used. Preferably, the range is 0.001 to 1.0% by weight with respect to the rinsing liquid at the time of use.

When the finishing liquid used in the present invention is a desensitizing liquid containing a water-soluble resin, the above pH
Conditioning agents, preservatives, fungicides, and antifoaming agents can be included in the same manner. As the desensitizing solution, basically, an aqueous solution of about 15 to 20% of gum arabic is often used. Various water-soluble resins other than gum arabic are used as a main component of the desensitizing solution. For example, dextrin, stellavic, structan, alginates, polyacrylates, hydroxyethylcellulose, polyvinylpyrrolidone, polyacrylamide, methylcellulose, hydroxypropylcellulose, hydroxymethylcellulose, carboxyalkylcellulose salts, water-soluble polysaccharides extracted from soybean okara Are preferable, and pullulan, a pullulan derivative, and polyvinyl alcohol are also preferable.

Further, modified starch derivatives such as roasted starch such as British gum, enzyme-modified dextrin such as enzyme dextrin and Shardinger dextrin, oxidized starch represented by solubilized starch, modified pregelatinized starch and non-modified pregelatinized starch, etc. Alpha starch, phosphate starch, fat starch, sulfate starch, esterified starch such as starch nitrate, starch xanthate and starch carbamate, carboxyalkyl starch, hydroxyalkyl starch, sulfoalkyl starch, cyanoethyl starch, allyl starch, benzyl starch Carbamylethyl starch, etherified starch such as dialkylamino starch, crosslinked starch such as methylol crosslinked starch, hydroxyalkyl crosslinked starch, phosphoric acid crosslinked starch, dicarboxylic acid crosslinked starch, starch polyacrylamide copolymer, starch polyacrylic Acid copolymer, starch-polyvinyl acetate copolymer, starch polyacrylonitrile copolymer, cationic starch polyacrylic acid ester copolymer,

A chaotic starch-vinyl polymer copolymer,
Starch graft polymers such as starch polystyrene maleic acid copolymer, starch polyethylene oxide copolymer and starch polypropylene copolymer are preferred. Examples of natural polymer compounds include starches such as potato starch, potato starch, tapioca starch, wheat starch and corn starch, and those obtained from algae such as carrageenan, laminaran, sea sour mannan, seaweed, Irish moss, agar and sodium alginate. , Trollo aoi, mannan, quince seed, pectin, tragacanth gum, karaya gum,
Vegetable mucilage such as xanthin gum, guaring gum, locust bingham, carob gum, benzoin gum,
Homopolysaccharides such as dextran, glucan, levan and the like, and microbial mucous substances such as hetropolysaccharide such as succinoglucan and suntan gum, glue, proteins such as gelatin, casein and collagen are preferred. These water-soluble resins can be used in combination of two or more, and preferably 5 to 40.
%, More preferably 10 to 30% by weight.

The desensitizing solution may contain the surfactant described for the rinsing solution. The content is suitably about 0.01 to 20% by weight based on the total weight of the desensitizing solution. In addition, glycerin, ethylene glycol, triethylene glycol and the like can be added to the desensitizing solution as necessary as a wetting agent. The preferred use amount of these wetting agents is 0.1 to 5% by weight.

Further, a chelate compound may be added to the desensitizing solution. Usually, the desensitized liquid is commercially available as a concentrated liquid, and is diluted with tap water, well water, or the like at the time of use. The calcium ions and the like contained in the diluted tap water or well water adversely affect the printing, and may cause the printed matter to be easily stained. . Preferred chelating compounds include, for example, ethylenediaminetetraacetic acid, its potassium salt, its sodium salt; diethylenetriaminepentaacetic acid, its potassium salt, its sodium salt; triethylenetetraminehexaacetic acid, its potassium salt, its sodium salt, hydroxyethylethylenediaminetriacetic acid Acetic acid, its potassium salt, its sodium salt; nitrilotriacetic acid, its sodium salt; 1-hydroxyethane-1,1-diphosphonic acid, its potassium salt;
Organic salts thereof such as aminotri (methylenephosphonic acid), potassium salt and sodium salt thereof, and phosphonoalkanetricarboxylic acids can be mentioned. Organic amine salts are also effective in place of the sodium and potassium salts of the above chelating agents. These chelating agents are selected from those which are stably present in the desensitizing solution composition and do not inhibit printability. The amount of addition is suitably 0.001 to 1.0% by weight based on the desensitizing solution at the time of use. The desensitizing liquid may be of an emulsified dispersion type, in which an organic solvent is used as the oil phase, and may be of a solubilized type with the aid of a solubilizing agent.

The remaining component of the finishing liquid is water. It is advantageous from the viewpoint of transportation that the finishing liquid is a concentrated liquid having a smaller content of water than at the time of use, and is diluted with water at the time of use. The degree of concentration in this case is suitably such that each component does not cause separation or precipitation.
Further, a solidified finishing agent in which water is removed by a spray drying method or the like or a solid material is mixed is also a preferred embodiment.

The photosensitive lithographic printing plate to which the method for processing a photosensitive lithographic printing plate of the present invention is applied includes a conventional positive type / negative type photosensitive lithographic printing plate using an aluminum plate as a support, and a photopolymerization type photosensitive lithographic printing plate. Lithographic printing plates and positive / negative infrared-sensitive lithographic printing plates.

[0024]

[Positive photosensitive lithographic printing plate] As the positive photosensitive lithographic printing plate, those having a photosensitive layer containing a polymer binder and an o-quinonediazide compound as main components are mentioned. A positive photosensitive lithographic printing plate described in JP-A-134002 is used.

[0025]

[Negative photosensitive lithographic printing plate] Examples of the negative photosensitive lithographic printing plate include those having a photosensitive layer containing a photosensitive diazo compound, a photocrosslinkable photosensitive layer, and the like. And a photosensitive lithographic printing plate having a negative photosensitive layer, which is described in detail in JP-A-282079.

[0026]

[Photopolymerizable photosensitive lithographic printing plate] Examples of the photopolymerizable photosensitive lithographic printing plate include a lithographic printing plate using a photopolymerizable composition described in detail in JP-A-8-220758. .

[0027]

[Infrared-sensitive lithographic printing plate] As the infrared-sensitive lithographic printing plate, a negative-type infrared-sensitive lithographic printing plate and a positive-type infrared-sensitive lithographic printing plate as described below are preferably used, but are not limited thereto. It is not something to be done.

[0028]

[Negative-type infrared-sensitive lithographic printing plate] The photosensitive composition layer of the negative-type infrared-sensitive lithographic printing plate is (A) a compound which decomposes by light or heat to generate an acid, and (B) a crosslinking agent which is crosslinked by an acid. , (C) at least one of alkali-soluble resins,
It contains (D) an infrared absorber and (E) other additives.
In negative-working infrared-sensitive lithographic printing plates, the energy imparted by solid-state lasers and semiconductor lasers that emit infrared radiation is converted into thermal energy by (D) an infrared absorber, thereby (A) decomposed by light or heat. As a result, the compound that generates an acid is decomposed to generate an acid, and the acid promotes a cross-linking reaction between (B) a cross-linking agent cross-linked by the acid and (C) an alkali-soluble resin, whereby image formation is performed. Things.

[0029]

[Positive-type infrared-sensitive lithographic printing plate] Conventionally known positive-type infrared-sensitive lithographic printing plate materials include, for example,
JP-A-285275 describes an image recording material in which a substance that absorbs light and generates heat, various onium salts, quinonediazide compounds, and the like are added to an alkali-soluble resin having a phenolic hydroxyl group such as a novolak resin.
On the other hand, a substance that absorbs light and generates heat, a resin soluble in an aqueous alkali solution having a phenolic hydroxyl group, and a copolymer containing at least one of the following (a) to (c) as a copolymer component in an amount of 10 mol% or more: And a positive type infrared-sensitive lithographic printing plate comprising: In this system, the two kinds of resins are insolubilized in an aqueous alkali solution due to strong interaction, but when heated, it is presumed that the interaction weakens due to heat and becomes soluble in the aqueous alkali solution. (A) A monomer having a sulfonamide group in which at least one hydrogen atom is bonded to a nitrogen atom in one molecule. (B) A monomer having an active imino group in one molecule. (C) Acrylamide having a phenolic hydroxyl group. , Methacrylamide, acrylate, methacrylate, or hydroxystyrene. In the present invention, these positive-working infrared-sensitive lithographic printing plates are preferably used.

[0030]

[Common processing] In the method for processing a photosensitive lithographic printing plate of the present invention, a positive-working / negative-working photosensitive lithographic printing plate, a light-curing photosensitive lithographic printing plate, and a negative-working and positive-working infrared-sensitive lithographic printing plate are used. It is possible to perform common processing using the same processing solution with the same automatic developing machine.

[0031]

[Exposure / Development / Post-processing] An infrared-sensitive lithographic printing plate is exposed by a plate setter equipped with a laser having an emission wavelength in the near infrared to infrared region. As such a laser, a solid-state laser or a semiconductor laser that emits infrared light having a wavelength of 760 nm to 1200 nm is preferable. In the present invention, the developing treatment may be performed immediately after the laser irradiation, but it is preferable to perform the heating treatment between the laser irradiation step and the developing step. The heat treatment is preferably performed in a range of 80 ° C. to 150 ° C. for 10 seconds to 5 minutes. By this heat treatment, the laser energy required for recording at the time of laser irradiation can be reduced. After performing a heat treatment as needed, it is developed and post-processed by the processing method of the present invention. Further, the ultraviolet-visible light-sensitive lithographic printing plate is exposed through a transparent original, for example, a mercury lamp, a metal halide lamp, a xenon lamp, a chemical lamp, a tungsten lamp, a carbon arc lamp, and the like, and then developed by the processing method of the present invention. Post-processed. Further, the photopolymerizable photosensitive lithographic printing plate is subjected to a scanning treatment with an argon laser and a YAG laser, followed by a heating treatment if necessary, followed by development and post-treatment by the treatment method of the present invention.

[0032]

[Automatic Developing Machine] In the method for processing a photosensitive lithographic printing plate of the present invention, it may or may not be washed with water after development and before finishing. By washing with water, it is possible to reduce somewhat the amount of aluminum ion dissolved in the developing solution on the plate surface after development into the finishing bath.
Therefore, the plate making process according to the method of the present invention is performed, for example, by developing →
(Washing) → Desensitization and development → (Washing) → Rinsing and development →
(Washing with water) → desensitization → desensitization and development → (washing with water) → rinsing → rinsing, development → (washing with water) → rinsing → desensitization. The method for processing a photosensitive lithographic printing plate of the present invention is preferably carried out using an automatic developing machine. Further, it is preferable to use the developing solution and the finishing solution while replenishing them.
The automatic developing machine has a development processing bath and a post-processing bath (rinse processing bath,
A desensitizing bath, etc.), and comprises a device for transporting a photosensitive lithographic printing plate, each processing bath and a spraying device, and an overflow section from a post-treatment bath to a post-treatment bath in the preceding stage. While the photosensitive lithographic printing plate is transported horizontally, each processing solution pumped up by a pump is sprayed from a spray nozzle to perform development and post-processing.
Recently, a method is also known in which a photosensitive lithographic printing plate is immersed and conveyed in a processing bath filled with a processing solution by a guide roll or the like in a liquid to perform development processing. In such automatic processing, processing can be performed while replenishing the developing bath and the post-processing bath with respective replenishers according to the processing amount, the operating time, and the like.

In the method of the present invention, after the photosensitive lithographic printing plate is exposed and developed, a desensitizing treatment or a rinsing treatment is performed in two or more processing baths, and a replenisher is replenished to a final processing bath. The embodiment can be carried out in such a manner that the overflow wastewater is discharged to the preceding treatment bath, and the overflow wastewater is sequentially replenished to the preceding treatment bath in the same manner. For example, in the case of desensitizing treatment, after development, the desensitizing treatment is performed in two or more processing baths, and the desensitizing replenisher is replenished to the final desensitizing bath, and the overflow drainage is added to the preceding stage. , And the overflow wastewater is sequentially replenished to the preceding treatment bath in the same manner. By such a method, the amount of waste liquid of the processing liquid can be suppressed, and stable processing can be performed for a long time. From the viewpoint of simplification of the automatic developing machine, installation space, manufacturing cost, and the like, the automatic developing machine preferably has a two-stage desensitizing bath or a rinsing bath.

[0034]

[Developer] Unless otherwise specified, the developer and the developer replenisher are collectively referred to as a developer. The developer used in the processing method of the present invention is a developer containing a non-reducing sugar and a base (excluding silicate) as main components. Examples of such a developing solution are disclosed in
Developers described in JP-A-160631 and JP-A-8-234647 are preferably used. Among them, preferred examples include a developer described in JP-A-8-305039. Specific description of a preferred developer is as follows.
It contains at least one compound selected from non-reducing sugars and at least one base (excluding silicate), and has a pH of 9.0.
現 像 13.8.

Such non-reducing sugars are saccharides having no free aldehyde group or ketone group and exhibiting no reducing property. Trehalose-type oligosaccharides in which reducing groups are bonded to each other, or a non-saccharide in which a reducing group of a saccharide is bonded to a non-saccharide. Glycosides and saccharides are classified as sugar alcohols that have been reduced by hydrogenation, and both are suitably used in the present invention. Trehalose-type oligosaccharides include saccharose and trehalose, and examples of glycosides include alkyl glycosides, phenol glycosides, and mustard oil glycosides. As sugar alcohols, D, L-arabit,
Rebit, Xylit, D, L-Sorbit, D, L-
Mannit, D, L-idit, D, L-talit, zuricit and allozurcit. Further, maltitol obtained by hydrogenating disaccharide maltose and a reductant (reduced starch syrup) obtained by hydrogenating oligosaccharide are preferably used. Among these, the non-reducing sugars preferred in the present invention are sugar alcohols and trehalose-type oligosaccharides. Among them, D-sorbitol, saccharose, and reduced starch syrup have a buffering action in an appropriate pH range and are low in price. preferable.

These non-reducing sugars can be used alone or in combination of two or more, and their ratio in the developing solution is preferably 0.1 to 30% by weight, more preferably,
1 to 20% by weight. Below this range, a sufficient buffering effect cannot be obtained, and at concentrations above this range, it is difficult to achieve high concentration, and there is a problem of cost increase. As the base to be combined with the non-reducing sugar, a conventionally known alkali agent can be used. For example, sodium hydroxide, potassium, lithium, trisodium phosphate, potassium, ammonium, disodium phosphate, potassium, ammonium, sodium carbonate, potassium, ammonium, sodium hydrogencarbonate, potassium, ammonium And inorganic alkali agents such as sodium borate, potassium and ammonium. Further, monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, triisopropylamine, n-butylamine, monoethanolamine,
Organic alkaline agents such as diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, ethyleneimine, ethylenediamine and pyridine are also used.

These alkali agents are used alone or in combination of two or more. Among these, sodium hydroxide and potassium hydroxide are preferred. The reason is,
This is because adjusting these amounts with respect to the non-reducing sugar enables pH adjustment in a wide pH range. Further, trisodium phosphate, potassium phosphate, sodium carbonate, potassium phosphate and the like are also preferable since they themselves have a buffering action. These alkaline agents raise the pH of the developer composition from 9.0 to 13.
8 and the amount of addition is the desired p.
It is determined by the type and amount of H and non-reducing sugar, but a more preferable pH range is 10.0 to 13.2. In the developing solution used in the processing method of the present invention, an alkali metal salt of a non-reducing sugar can be used as a main component instead of the combination of the non-reducing sugar and the alkali agent. The non-reducing sugar salt is prepared by mixing a non-reducing sugar and an alkali metal hydroxide and heating the mixture to a temperature equal to or higher than the melting point of the non-reducing sugar to dehydrate or drying a mixed aqueous solution of the non-reducing sugar and the alkali metal hydroxide. can get.

The developing solution is further described in JP-A-8-160631.
Or an alkaline buffer solution comprising a weak acid other than a saccharide and a strong base described in JP-A-8-13447. The weak acid used as such a buffer is preferably one having a dissociation constant (pKa) of 10.0 to 13.2. Examples of such a weak acid include IONISATION CONSTANTS O issued by PergamonPress.
FORGANICACIDS IN AQUEOUS
SOLUTION or the like, for example, 2,2,3,3-tetrafluoropropanol-1
(PKa 12.2.74), trifluoroethanol (12.74).
37), alcohols such as trichloroethanol (12.24) and pyridine-2-aldehyde (12.6).
8), aldehydes such as pyridine-4-aldehyde (12.05), salicylic acid (13.0), 3-hydroxy
2-Naphthoic acid (12.84) and catechol (12.84)
6), gallic acid (12.4) and sulfosalicylic acid (1)
1.7), 3,4-dihydroxysulfonic acid (12.2),
4-dihydroxybenzoic acid (11.94), 1,2,4-trihydroxybenzene (11.82), hydroquinone (11.56), pyrogallol (11.34), o-cresol (10) .33), resorcinol (11.27),
p-cresol (10.27) and m-cresol (1)
0.09) and other compounds having a phenolic hydroxyl group,

2-butanone oxime (12.45), acetoxime (12.42), 1,2-cycloheptanedione dioxime (12.3), 2-hydroxybenzaldehyde oxime (12.10), Dimethylglyoxime (11.9), ethanediamide dioxime (11.37),
Oximes such as acetophenone oxime (11.35), adenosine (12.56) and inosine (12.35).
5), guanine (12.3), cytosine (12.2),
Hypoxanthine (12.1), xanthine (11.9)
Nucleic acid-related substances such as diethylaminomethylphosphonic acid (12.32), 1-amino-3,3,3-trifluorobenzoic acid (12.29) and isopropylidene diphosphonic acid (12.10) ), 1,1-ethylidene diphosphonic acid (1
1.54), 1,1-ethylidene diphosphon-1-hydroxy (11.52), benzimidazole (12.86),
Weak acids such as thiobenzamide (12.8), picoline thioamide (12.55) and barbituric acid (12.5).

Among these weak acids, preferred are sulfosalicylic acid and salicylic acid. As the base to be combined with these weak acids, sodium hydroxide, ammonium hydroxide, potassium hydroxide and lithium hydroxide are preferably used.
These alkali agents are used alone or in combination of two or more. The above-mentioned various alkaline agents are used by adjusting the pH within a preferred range depending on the concentration and combination.

[Surfactant] To the developer, various surfactants and organic solvents can be added as necessary for the purpose of accelerating the developing property, dispersing the developing residue and increasing the ink affinity of the printing plate image area. Preferred surfactants include anionic,
Cationic, nonionic and amphoteric surfactants are included. Preferred examples of the surfactant include polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene polystyryl phenyl ethers, polyoxyethylene polyoxypropylene alkyl ethers, glycerin fatty acid partial esters, and sorbitan. Fatty acid partial esters, pentaerythritol fatty acid partial esters, propylene glycol monofatty acid esters, sucrose fatty acid partial esters, polyoxyethylene sorbitan fatty acid partial esters, polyoxyethylene sorbitol fatty acid partial esters, polyethylene glycol fatty acid esters, poly Glycerin 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 alkylamine, triethanolamine fatty acid ester, trialkylamine oxide, fatty acid salts, abieticin Acid salts, hydroxyalkanesulfonates, alkanesulfonates, dialkylsulfosuccinates, α-olefinsulfonates, linear alkylbenzenesulfonates, branched alkylbenzenesulfonates, alkylnaphthalenesulfonates, alkylphenoxypoly Oxyethylene propyl sulfonates, polyoxyethylene alkyl sulfophenyl ether salts, N-methyl-N-
Oleyltaurine sodium salt, N-alkylsulfosuccinic acid monoamide disodium salt, petroleum sulfonates,
Sulfated tallow oil, sulfate salts of fatty acid alkyl esters, alkyl sulfate salts, polyoxyethylene alkyl ether sulfate salts,

Fatty acid monoglyceride sulfate salts,
Polyoxyethylene alkyl phenyl ether sulfates, polyoxyethylene styryl phenyl ether sulfates, alkyl phosphates, polyoxyethylene alkyl ether phosphates, polyoxyethylene alkyl phenyl ether phosphates, styrene / anhydrous Anionic surfactants such as partially saponified maleic acid copolymers, partially saponified olefin / maleic anhydride copolymers, naphthalenesulfonate formalin condensates, alkylamine salts,
Quaternary ammonium salts such as tetrabutylammonium bromide, cationic surfactants such as polyoxyethylene alkylamine salts and polyethylene polyamine derivatives, carboxybetaines, alkylaminocarboxylic acids, sulfobetaines, aminosulfates, and imidazolines And other amphoteric surfactants. Among the surfactants listed above, those with polyoxyethylene,
It can be read as a polyoxyalkylene such as polyoxymethylene, polyoxypropylene, polyoxybutylene, and their surfactants are also included.

Further preferred surfactants are fluorine-based surfactants containing a perfluoroalkyl group in the molecule. Such fluorosurfactants include perfluoroalkyl carboxylate, perfluoroalkyl sulfonate, anionic type such as perfluoroalkyl phosphate, amphoteric type such as perfluoroalkyl betaine,
Cationic and perfluoroalkylamine oxides such as perfluoroalkyltrimethylammonium salts, perfluoroalkylethylene oxide adducts, oligomers containing perfluoroalkyl groups and hydrophilic groups,
Non-ionic types such as oligomers containing perfluoroalkyl groups and lipophilic groups, oligomers containing perfluoroalkyl groups, hydrophilic groups and lipophilic groups, and urethanes containing perfluoroalkyl groups and lipophilic groups are included. The above-mentioned surfactants can be used alone or in combination of two or more, and 0.001 to 10% by weight in a developer.
More preferably, it is added in the range of 0.01 to 5% by weight.

[Development Stabilizer] Various development stabilizers are used in the developer. Preferred examples thereof include polyethylene glycol adducts of sugar alcohols described in JP-A-6-282079, tetraalkylammonium salts such as tetrabutylammonium hydroxide, phosphonium salts such as tetrabutylphosphonium bromide, and iodonium such as diphenyliodonium chloride. Salts are mentioned as preferred examples. Further, anionic surfactants or amphoteric surfactants described in JP-A-50-51324, water-soluble cationic polymers described in JP-A-55-95946, and JP-A-56-1
There is a water-soluble amphoteric polymer electrolyte described in Japanese Patent No. 42528.

Further, an organic boron compound to which an alkylene glycol is added as disclosed in JP-A-59-84241, and a water-soluble surfactant of the polyoxyethylene / polyoxypropylene block polymerization type described in JP-A-60-111246. Japanese Patent Application Laid-Open No. Sho 60-129750, polyoxyethylene / polyoxypropylene-substituted alkylenediamine compounds, Japanese Patent Application Laid-Open No. Sho 61-215554, polyethylene glycol having a weight average molecular weight of 300 or more, and Japanese Patent Application Laid-Open No. Sho 63-175858. JP-A-2-39157 discloses a fluorine-containing surfactant having a cationic group, a water-soluble ethylene oxide addition compound obtained by adding 4 mol or more of ethylene oxide to an acid or alcohol, and a water-soluble polyalkylene compound. No.

[Organic Solvent] An organic solvent is further added to the developer if necessary. As such an organic solvent, those having a solubility in water of about 10% by weight or less are suitable, and preferably selected from those having a solubility of 5% by weight or less. For example, 1
-Phenylethanol, 2-phenylethanol, 3-
Phenyl-1-propanol, 4-phenyl-1-butanol, 4-phenyl-2-butanol, 2-phenyl-1-butanol, 2-phenoxyethanol, 2-benzyloxyethanol, o-methoxybenzyl alcohol, m-methoxybenzyl Examples thereof include alcohol, p-methoxybenzyl alcohol, benzyl alcohol, cyclohexanol, 2-methylcyclohexanol, 3-methylcyclohexanol and 4-methylcyclohexanol, N-phenylethanolamine and N-phenyldiethanolamine. The content of the organic solvent is 0.1 to 5% by weight based on the total weight of the used solution. The amount used is closely related to the amount used of the surfactant, and it is preferable to increase the amount of the surfactant as the amount of the organic solvent increases. This is because when the amount of the surfactant is small and the amount of the organic solvent is large, the organic solvent is not completely dissolved, and therefore, it is impossible to expect good developing property.

[Reducing Agent] A reducing agent may be further added to the developer. This is to prevent the printing plate from being stained. Preferred organic reducing agents include phenolic compounds such as thiosalicylic acid, hydroquinone, metol, methoxyquinone, resorcin, and 2-methylresorcin; and amine compounds such as phenylenediamine and phenylhydrazine. Further preferred inorganic reducing agents include sodium salts, potassium salts, and ammonium salts of inorganic acids such as sulfurous acid, bisulfite, phosphorous acid, bisulfite, diphosphite, thiosulfate and dithionite. Salts and the like can be mentioned. Among these reducing agents, sulfites are particularly excellent in the stain prevention effect. These reducing agents are preferably added to the developing solution at the time of use at a concentration of 0.0.
It is contained in the range of 5 to 5% by weight.

[Organic carboxylic acid] An organic carboxylic acid can be further added to the developer. Preferred organic carboxylic acids are aliphatic and aromatic carboxylic acids having 6 to 20 carbon atoms. Specific examples of the aliphatic carboxylic acid include caproic acid, enantiic acid, caprylic acid, lauric acid, myristic acid, palmitic acid and stearic acid, and particularly preferred are alkanoic acids having 8 to 12 carbon atoms. . Further, unsaturated fatty acids having a double bond in the carbon chain or branched fatty acids may be used. The aromatic carboxylic acid is a compound in which a carboxyl group is substituted on a benzene ring, a naphthalene ring, an anthracene ring, or the like. Specifically, o-chlorobenzoic acid, p-chlorobenzoic acid, o-hydroxybenzoic acid, p- Hydroxybenzoic acid, o-aminobenzoic acid, p-aminobenzoic acid, 2,4
-Dihydroxybenzoic acid, 2,5-dihydroxybenzoic acid, 2,6-dihydroxybenzoic acid, 2,3-dihydroxybenzoic acid, 3,5-dihydroxybenzoic acid, gallic acid, 1-hydroxy-2-naphthoic acid, 3 -Hydroxy-2-naphthoic acid, 2-hydroxy-1-naphthoic acid,
There are 1-naphthoic acid and 2-naphthoic acid, and hydroxynaphthoic acid is particularly effective.

The above aliphatic and aromatic carboxylic acids are preferably used as a sodium salt, a potassium salt or an ammonium salt in order to increase the water solubility. The content of the organic carboxylic acid in the developer is not particularly limited, but if the content is less than 0.1% by weight, the effect is not sufficient, and if the content is more than 10% by weight, the effect cannot be further improved. Dissolution may be hindered when an additive is used in combination. Therefore, the preferred addition amount is 0.1 to 10% by weight, more preferably 0.5 to 4% by weight, based on the developer used.

[Others] The developer may further contain a preservative, a colorant, a thickener, an antifoaming agent, a water softener and the like, if necessary. Examples of the water softener include polyphosphoric acid and its sodium salt, potassium salt and ammonium salt, ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, triethylenetetraminehexaacetic acid, hydroxyethylethylenediaminetriacetic acid, nitrilotriacetic acid, 1,2-diaminocyclohexanetetraacetic acid. Aminopolycarboxylic acids such as acetic acid and 1,3-diamino-2-propanoltetraacetic acid and their sodium, potassium and ammonium salts;
Aminotri (methylenephosphonic acid), ethylenediaminetetra (methylenephosphonic acid), diethylenetriaminepenta (methylenephosphonic acid), triethylenetetraminehexa (methylenephosphonic acid), hydroxyethylethylenediaminetri (methylenephosphonic acid) and 1-
Examples include hydroxyethane-1,1-diphosphonic acid and their sodium, potassium and ammonium salts.

The optimum value of such a water softener varies depending on the chelating power thereof, the hardness of the hard water used and the amount of the hard water. The range is from 0.01 to 5% by weight, more preferably from 0.01 to 0.5% by weight. If the added amount is less than this range, the intended purpose is not sufficiently achieved, and if the added amount is larger than this range, an adverse effect on an image portion such as color omission appears. The remaining component of the developer is water. It is advantageous from the viewpoint of transportation that the developing solution is a concentrated solution in which the content of water is smaller than that at the time of use, and is diluted with water at the time of use. The degree of concentration in this case is suitably such that each component does not cause separation or precipitation. Further, a solidified developer in which water is removed by a spray drying method or the like or a solid material is mixed is also a preferred embodiment.

[0053]

According to the method for producing a photosensitive lithographic printing plate of the present invention, generation of insoluble residue in a finishing bath can be suppressed, clogging of a filter and a spray can be prevented, and stable processing can be continued. As a result, it is possible to provide a lithographic printing plate free from printing stains and defective ink deposition over a long period of time.

[0054]

The present invention will be described in detail with reference to the following examples.
All percentages in the following examples are% by weight unless otherwise specified.

[Example 1] (Preparation of substrate) JIS having a thickness of 0.24 mm
Surface of A1050 aluminum plate with nylon brush and 4
After graining using an aqueous suspension of 00 mesh pumistone, it was thoroughly washed with water. After etching by dipping in a 10% aqueous sodium hydroxide solution at 70 ° C. for 60 seconds, the substrate was washed with running water, washed with 20% HNO ₃ for neutralization, and washed with water. This was subjected to electrolytic surface roughening treatment in a 1% nitric acid aqueous solution at an anode time electricity quantity of 260 coulomb / dm ² using a sine wave alternating current under the condition of VA = 12.7V. When the surface roughness was measured, it was 0.6 μm (Ra display). Then immersed in a 30% aqueous solution of H ₂ SO ₄ ,
After desmutting for 20 minutes, anodizing was performed in a 20% H ₂ SO ₄ aqueous solution so that the current density became 14 A / dm ² and the amount of anodized film became 2.5 g / m ² .
The substrate was treated with a 1% by weight aqueous solution at 20 ° C. for 10 seconds and washed with water to form a substrate. The polymer compound [a] shown below was applied to the surface of the substrate thus treated, and dried at 90 ° C. for 10 seconds. The coating amount after drying was 10 mg / m ² . Polymer compound [a] (see the following formula) 0.2 g methanol 100 g water 1 g

[0055]

Embedded image

Thus, a substrate [A] was prepared. A photosensitive layer was formed by applying the following photosensitive solution [A] on the substrate [A]. The coating amount of the photosensitive layer after drying was 1.8 g / m ² . Photosensitive solution [A] Esterified product of 1,2-diazonaphthoquinone-5-sulfonyl chloride and pyrogallol-acetone resin (described in Example 1 of U.S. Pat. No. 3,635,709) 0.8 g Binder Novolak I (See the following formula) 1.5 g Novolak II (see the following formula) 0.2 g Resin other than novolak III (see the following formula) 0.4 g p-n-octylphenol-formaldehyde resin (described in U.S. Pat. No. 4,123,279) 0.02 g naphthoquinone-1,2-diazide-4-sulfonic acid chloride 0.01 g tetrahydrophthalic anhydride 0.02 g benzoic acid 0.02 g pyrogallol 0.05 g 4- [p-N, N-bis (ethoxy Carbonylmethyl) aminophenyl] -2,6-bis (trichloromethyl) -S Triazine 0.07 g Victoria Pure Blue BOH (dye made by Hodogaya Chemical Co., Ltd. in which the counter anion is changed to 1-naphthalenesulfonic acid) 0.045 g F176PF (fluorinated surfactant) (Dainippon Ink Chemical Industry Co., Ltd.) 0.01 g methyl ethyl ketone 15 g 1-methoxy-2-propanol 10 g

[0057]

Embedded image

Further, in order to shorten the vacuum adhesion time, a mat layer was formed by the following method. A 12% aqueous solution in which a part of a copolymer of methyl methacrylate / ethyl acrylate / acrylic acid (weight ratio 65:20:15) was prepared as a resin solution for forming a mat layer was prepared. The number of rotations of the atomizing head is 25,000 rpm, the amount of the resin solution fed is 40 ml / min, and the voltage applied to the atomizing head is -90.
kV, the ambient temperature at the time of application was 25 ° C., and the relative humidity was 50%. Steam was sprayed on the application surface 2.5 seconds after application to wet the surface, and 3 seconds after the application, the temperature was 60 ° C. and the humidity was 10%. Air was blown for 5 seconds to dry. The height of the mat was about 6 μm, the size was about 30, and the number was 150 pieces / mm ² . Thus, a positive photosensitive lithographic printing plate was prepared.

The photosensitive lithographic printing plate thus prepared was
It was cut to 030 mm x 800 mm, and many sheets were prepared. 1m
After a 1 minute image exposure with a 3 kW metal halide lamp from a distance of, a first desensitizing bath and a second desensitizing bath are provided after the immersion type developing bath, and the developing bath and the second A mechanism for replenishing the replenisher with a replenisher, a mechanism for discharging the overflow of the second desensitizer to the first desensitizer, and a mechanism for transporting the photosensitive lithographic printing plate. Processing was performed on an automatic processor having rollers. At that time, 20 L of the following developer [A] was charged into the developing bath,
The temperature was adjusted to 30 ° C., and 4 L of the following desensitizing solution [A] was charged into the first desensitizing bath, and 4 L of the desensitizing solution [A] was charged into the second desensitizing bath. It is. Developer [A] D-Sorbit 2.5% Potassium hydroxide 1.3% Diethylenetriaminepenta (methylenephosphonic acid) 5Na salt 0.1% Water 96.1%

Desensitized solution [A] Arabic gum 1.6% Enzyme-modified potato starch 8.8% Phosphorylated waxy corn starch 0.80% Dioctyl sulfosuccinate sodium salt 0.10% Citric acid 0.14% α-alanine 0.11% EDTA-tetrasodium salt 0.10% dodecyl diphenyl ether disulfonic acid 2Na salt 0.18% ethylene glycol 0.72% benzyl alcohol 0.87% sodium dehydroacetate 0.04% emulsion silicone defoamer 0.01% Water 86.53%

The processing was carried out at a speed of passing through the developing bath in 12 seconds, and 160 plates per day for 3 months continuously.
26 cc per m ^{2 of the following} replenisher [A]
Refilled. The above desensitizing solution [A] is supplied to the second desensitizing bath.
Was 20cc replenishment per 1m ^2. Developing replenisher [A] D-Sorbit 5.6% Potassium hydroxide 2.5% Diethylenetriaminepenta (methylenephosphonic acid) 5Na salt 0.2% Water 91.7% No adhesion is observed on the treated plate. Also, printing could be performed without any problem. After the completion of the processing, the inside of the automatic developing machine was observed. As a result, no precipitate was found in the first desensitizing bath, and no clogging was observed in the spray pipe.

[0062]

Example 2 A desensitizing solution [B] was prepared by replacing the citric acid of the desensitizing solution [A] with tartaric acid 0.10% (water was changed to 86.57%) in Example 1. All treatments were carried out in the same manner as in Example 1 except that [A] was used. Good results were obtained as in Example 1.

Example 3 A desensitizing solution [C] in which the citric acid of the desensitizing solution [A] was replaced with 0.20% gluconic acid (water was 86.47%) in Example 1 was desensitized. All treatments were carried out in the same manner as in Example 1 except for using the solution [A]. Good results were obtained as in Example 1.

[0063]

Comparative Example 1 The desensitizing solution [D] was prepared by replacing the citric acid of the desensitizing solution [A] in Example 1 with phosphoric acid 0.20% (water was changed to 86.47%). All treatments were carried out in the same manner as in Example 1 except for using the solution [A]. As a result, the first
A white gel-like substance was generated on the conveying roller at the entrance of the desensitizing bath, and was transferred to the plate to cause printing stains. Three months later, the inside of the automatic developing machine was observed. As a result, a sludge-like precipitate was found in the first desensitizing bath, and the spray pipe was clogged.

Comparative Example 2 Desensitizing liquid [E] was prepared by replacing citric acid of desensitizing liquid [A] with 0.20% of succinic acid (water was changed to 86.47%) in Example 1. All treatments were carried out in the same manner as in Example 1 except for using the solution [A]. As a result, as a result, a white gel-like substance was generated on the entrance conveyance roller of the first desensitizing bath, and was transferred to the plate, resulting in printing stains. Three months later, the inside of the automatic developing machine was observed. As a result, a sludge-like precipitate was found in the first desensitizing bath, and the spray pipe was clogged.

[0064]

Comparative Example 3 In Example 1, the following developer [B] and developer replenisher [B] were used instead of developer [A] and developer replenisher [A]. ] Was replenished in the same manner as in Example 1 except that 35 cc was replenished per 1 m ² . Developing solution [B] [SiO ₂ ] / [K ₂ O] molar ratio 1.16 SiO ₂ 1.4% aqueous solution of potassium silicate 99.9% Diethylenetriaminepenta (methylene phosphonic acid) 5Na salt 0.1% Development replenisher [B] [SiO ₂ ] / [K ₂ O] molar ratio 0.98 SiO ₂ 2.0% aqueous solution of potassium silicate 99.8% diethylenetriaminepenta (methylene phosphonic acid) 5Na salt 0.2% No deposits were observed, and printing could be performed without any problem. After completion of the processing, as a result of observing the inside of the automatic developing machine, there was no precipitate in the first desensitizing bath,
Also, no clogging was found in the spray pipe. However, a gel-like residue was deposited on the bottom of the developing bath, and a metal brush was required for cleaning.

The types and results of the processing solutions of Examples 1 to 3 and Comparative Examples 1 to 3 (the generation of scum in the developing bath, the generation of roller dirt and scum in the first desensitizing bath, and the generation of scum on the plate) Are summarized in Table 1 below. In addition, in the table, when generation | occurrence | production of scum was recognized, it is set to x, and when scum is not recognized, it is set to (circle).

[0066]

[Table 1] Developing solution / replenisher Desensitizing solution Developing bath debris First desensitizing bath plate roller Dirt Debris Adhered debris Example 1 [A] / [A] [A] ○ ○ ○ ○ Example 2 [A] / [ A] [B] ○ ○ ○ ○ Example 3 [A] / [A] [C] ○ ○ ○ ○ Comparative Example 1 [A] / [A] [D] ○ × × × Comparative Example 2 [A] / [A] [E] ○ × × × Comparative Example 3 [B] / [B] [A] × ○ ○ ○

Claims (1)

[Claims] In a step of subjecting a photosensitive lithographic printing plate having an aluminum plate as a support to exposure, developing with a developer containing a non-reducing sugar and a base (excluding silicate), and then performing a finishing treatment, Contains at least one oxycarboxylic acid.