JPH04287046A - Processing method for photosensitive planographic printing plate - Google Patents

Abstract

PURPOSE:To allow the stable maintenance of development quality and to simplify the method and device for development replenishing in the method for subjecting photosensitive planographic printing plates of a negative type and positive type to development processing with a developer common for negatives and positives while replenishing this liquid with a replenishing liquid. CONSTITUTION:The developer and the replenishing liquid thereof used in the method for developing the planographic printing plates of the negative and positive type with the developer common for negatives and positives to be repetitively used under the replenishment with the replenishing liquid by using an automatic developing machine contain alkali silicate, surfactants, org. solvents, reducing agents, and chelate agents and the development replenishing liquid varies from the developer in the concn. ratios of at least one kind thereof and the development replenishing liquid consists of one kind of the liquid.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a method for processing photosensitive lithographic printing plates, and more specifically, a method for processing a negative photosensitive lithographic printing plate and a positive photosensitive lithographic printing plate using an automatic processor to replenish a replenisher. The present invention relates to a processing method for developing with a negative/positive developer.

0002

[Prior art] A negative-working photosensitive lithographic printing plate and a positive-working photosensitive lithographic printing plate are processed using one automatic developing machine, and a common developer for the negative-working photosensitive lithographic printing plate and the positive-working photosensitive lithographic printing plate is used. As a method of replenishing the replenishing solution and performing stable treatment for a long period of time, we use a method that contains silicate as an alkaline agent and anionic surfactant,
A method of replenishing an alkaline developer containing sulfites, etc. with a developer replenisher having a higher content of alkaline agent, and a method of configuring the replenisher into two liquids to produce a negative-working photosensitive lithographic printing plate and a positive-working photosensitive JP-A-62-73271 discloses a method of replenishing by changing the mixing ratio with a lithographic printing plate.

However, in the former method, a difference tends to occur between the components actually consumed and the components replenished, and the development quality gradually deteriorates. Furthermore, the latter method requires two types of developer replenisher and equipment, making it uneconomical and complicated to manage.

0004

OBJECT OF THE INVENTION The object of the present invention is to develop a photosensitive lithographic printing plate in which a negative-working photosensitive lithographic printing plate and a positive-working photosensitive lithographic printing plate are developed by replenishing a replenisher with a common negative/positive developer. It is an object of the present invention to provide a method in which development quality can be stably maintained in a processing method, and a development replenishment method and an apparatus used therein can be simplified.

[0005]

[Structure of the Invention] The above-mentioned object of the present invention is to produce a negative-working photosensitive lithographic printing plate and a positive-working photosensitive lithographic printing plate using a developing solution for negative and positive use that can be repeatedly used by replenishing a developer replenisher using an automatic developing machine. In the development processing method for developing a printing plate, the developer and the developer replenisher contain an alkali silicate, a surfactant, an organic solvent, a reducing agent, and a chelating agent, and the alkali silicate, surfactant, and organic solvent is achieved by a method for processing a photosensitive lithographic printing plate, characterized in that the developer replenisher is different from the developer in the concentration ratio of the reducing agent and the chelating agent, and the developer replenisher is composed of one type of solution. .

[0006] Preferably, in the above processing method, the replenishment method for the developer replenisher is characterized in that the amount of replenishment is varied depending on the processing ratio of the negative-working photosensitive lithographic printing plate and the positive-working photosensitive lithographic printing plate. be.

The present invention will be explained in detail below.

The negative/positive developer used in the method of the present invention and its replenisher contain an alkali silicate as an alkaline agent. Examples of the alkali silicate include potassium silicate, sodium silicate, sodium metasilicate, potassium metasilicate, and ammonium silicate. The content of alkali silicate in the developer is preferably in the range of 0.3 to 10% by weight. In addition, alkali silicate is SiO2
The concentration is preferably in the range of 0.1 to 7.0% by weight.

[0009] Alkali agents other than alkali silicate can be used in combination with the developer and developer replenisher, such as potassium hydroxide, sodium hydroxide, lithium hydroxide, tribasic sodium phosphate, dibasic sodium phosphate, etc. , tribasic potassium phosphate, dibasic potassium phosphate, tribasic ammonium phosphate, dibasic ammonium phosphate, sodium metasilicate,
Inorganic alkaline agents such as sodium bicarbonate, sodium carbonate, potassium carbonate, ammonium carbonate, etc., organic alkaline agents such as mono-, di- or triethanolamine and tetraalkyl hydroxide can be used in combination.

The surfactant contained in the developer and developer replenisher in the present invention is preferably an anionic surfactant,
It is at least one type sent from a nonionic surfactant and a cationic surfactant.

Examples of anionic surfactants include higher alcohol (C8 to C22) sulfate ester salts [for example, sodium salt of lauryl alcohol sulfate, sodium salt of octyl alcohol sulfate, ammonium salt of lauryl alcohol sulfate, "Teepo
1-81 (trade name, manufactured by Ciel Chemical Co., Ltd.), sodium chloride alkyl sulfate, etc.], aliphatic alcohol phosphate ester salts (e.g., sodium salt of cetyl alcohol phosphate ester, etc.), alkylaryl sulfonates (e.g., sodium salt of dodecylbenzenesulfonic acid, sodium salt of isopropylnaphthalenesulfonic acid, sodium salt of dinaphthalene disulfonic acid, sodium salt of metanitrobenzenesulfonic acid, etc.), sulfonic acid salts of alkylamides (for example, C17H33CO
N(CH3)CH2SO3Na, etc.), and sulfonic acid salts of dibasic fatty acid esters (for example, sodium sulfosuccinate dioctyl ester, sodium sulfosuccinate dihexyl ester, etc.). Among these, sulfonate salts are particularly preferably used.

[0012] Nonionic surfactants include polyethylene glycol type and polyhydric alcohol type, and both can be used. From the viewpoint of development performance, polyethylene glycol type nonionic surfactants are preferred, and among these, polyethylene glycol type nonionic surfactants are preferred, and among them, those having three or more ethyleneoxy groups (-CH2CH2O-) and HL
B value (HLB is Hydrophile-Lipophile
leBalance) is 5 or more (more preferably 8
-20) Nonionic surfactants are more preferred.

Among nonionic surfactants, those having both ethyleneoxy and propyleneoxy groups are particularly preferred, and among these, those having an HLB value of 8 or more are more preferred.

Preferred examples of nonionic surfactants include compounds represented by the following general formulas [1] to [8].

[0015]

[Chemical formula 1]

In formulas [1] to [8], R represents a hydrogen atom or a monovalent organic group. The organic group includes, for example, a linear or branched alkyl group having 1 to 30 carbon atoms that may have a substituent {for example, an aryl group (phenyl, etc.)}, and an alkylcarbonyl group in which the alkyl moiety is the above-mentioned alkyl group. and a phenyl group which may have a substituent (for example, a hydroxyl group, an alkyl group as described above, etc.). a, b, c, m, n, x and y are each 1 to 4
Represents an integer of 0.

Next, specific examples of nonionic surfactants will be shown.

Polyethylene glycol, polyoxyethylene lauryl ether, polyoxyethylene nonyl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene behenyl ether,
Polyoxyethylene polyoxypropylene cetyl ether, polyoxyethylene polyoxypropylene behenyl ether, polyoxyethylene nonylphenyl ether, polyoxyethylene octylphenyl ether, polyoxyethylene stearylamine, polyoxyethylene oleylamine, polyoxyethylene stearamide, Polyoxyethylene oleic acid amide, polyoxyethylene castor oil, polyoxyethylene abiethyl ether, polyoxyethylene lanolin ether, polyoxyethylene monolaurate, polyoxyethylene monostearate, polyoxyethylene glyceryl monooleate, polyoxyethylene Glycer monostearate, polyoxyethylene propylene glycol monostearate, oxyethylene oxypropylene block polymer, distyrenated phenol polyethylene oxide adduct, tribenzylphenol polyethylene oxide adduct, octylphenol polyoxyethylene polyoxypropylene adduct, glycerol monostearate sorbitan monolaurate, polyoxyethylene sorbitan monolaurate, etc.

The weight average molecular weight of the nonionic surfactant is 3
The range is preferably from 00 to 10,000, and from 500 to 5,000.
A range of is particularly preferred. One type of nonionic surfactant may be contained alone, or two or more types may be used in combination.

Cationic surfactants are broadly classified into amine type and quaternary ammonium salt type, and any of these can be used.

Examples of amine types include polyoxyethylene alkyl amine, N-alkylpropylene amine, N-
-Alkyl polyethylene polyamine, N-alkyl polyethylene polyamine dimethyl sulfate, alkyl biguanide, long chain amine oxide, alkylimidazoline, 1-
Hydroxyethyl-2-alkylimidazoline, 1-acetylaminoethyl-2-alkylimidazoline, 2-
Examples include alkyl-4-methyl-4-hydroxymethyloxazoline.

Examples of quaternary ammonium salts include long-chain primary amine salts, alkyltrimethylammonium salts, dialkyldimethylethylammonium salts, alkyldimethylammonium salts, alkyldimethylbenzylammonium salts, alkylpyridinium salts, and alkyltrimethylammonium salts. Norinium salt, alkylisoquinolinium salt, alkylpyridinium sulfate, stearamidemethylpyridinium salt, acylaminoethyldiethylamine salt, acylaminoethylmethyldiethylammonium salt, alkylamidopropyldimethylbenzylammonium salt, fatty acid polyethylene polyamide, acylamino Ethylpyridinium salt, acylcolaminoformylmethylpyridinium salt,
Stearooxymethylpyridinium salt, fatty acid triethanolamine, fatty acid triethanolamine formate, trioxyethylene fatty acid triethanolamine, fatty acid dibutylaminoethanol, cetyloxymethylpyridinium salt, p-isooctylphenoxyethoxyethyldimethylbenzylammonium salt, etc. There is. (“Alkyl” in the above compound examples refers to carbon atoms having 6 to 20 carbon atoms,
It represents a straight-chain or partially substituted alkyl, and specifically, straight-chain alkyl such as hexyl, octyl, cetyl, and stearyl are preferably used. ) Among these,
Water-soluble quaternary ammonium salt type cationic surfactants are particularly effective, and among them, alkyltrimethylammonium salts, alkyldimethylbenzylammonium salts, ethylene oxide-added ammonium salts, and the like are preferred. Further, a polymer having a cationic component as a repeating unit is also a cationic surfactant in a broad sense, and is included in the cationic surfactant of the present invention. In particular, a polymer containing a quaternary ammonium salt obtained by copolymerizing with a lipophilic monomer can be suitably used. The weight average molecular weight of the polymer is in the range of 300 to 50,000, particularly preferably 5
The range is from 00 to 5000. These cationic surfactants may be used alone or in combination of two or more.

The surfactant is preferably contained in the developing solution in an amount of 0.01 to 10% by weight.

The organic solvent contained in the developer and developer replenisher according to the present invention preferably has a solubility in water of 10% by weight or less at 20°C, such as ethyl acetate, propyl acetate, butyl acetate, benzyl acetate, ethylene. Carboxylic acid esters such as glycol monobutylacetate, butyl lactate, butyl levulinate; ketones such as ethyl butyl ketone, methyl isobutyl ketone, cyclohexanone; ethylene glycol monobutyl ether, ethylene glycol benzyl ether, ethylene glycol monophenyl ether, Alcohols such as benzyl alcohol, methylphenyl carbinol, n-amyl alcohol, and methylamine alcohol; alkyl-substituted aromatic hydrocarbons such as xylene; halogenated hydrocarbons such as methylene dichloride, ethylene dichloride, and monochlorobenzene. be. One or more types of these organic solvents may be used. The content of the organic solvent in the developer is preferably in the range of 0.05 to 10% by weight.

As the reducing agent contained in the developer and developer replenisher according to the present invention, a water-soluble or alkali-soluble organic or inorganic reducing agent can be used.

Examples of organic reducing agents include phenolic compounds such as hydroquinone, methol, and methoxyquinone, and amine compounds such as phenylenediamine and phenylhydrazine. Examples of inorganic reducing agents include sodium sulfite, potassium sulfite, and ammonium sulfite. , sulfites such as sodium hydrogen sulfite and potassium hydrogen sulfite,
Phosphates such as sodium phosphite, potassium phosphite, sodium hydrogen phosphite, potassium hydrogen phosphite, sodium dihydrogen phosphite, dipotassium hydrogen phosphite, hydrazine, sodium thiosulfate, dithionite Examples include sodium, but the reducing agent that is particularly effective in the present invention is sulfite.

The reducing agent is preferably contained in the developing solution in an amount of 0.1 to 20% by weight. Examples of the chelating agent used in the method of the present invention include oxy compounds, oxycarboxylic acids, aminocarboxylic acids, enolizable polycarbonyl compounds, nitrogen compounds containing hydroxyl and carboxyl groups, phenols such as diethylbarbituric acid, citric acid, etc. Acid, tartaric acid, sugar acid, glycolic acid, adipic acid, ascorbic acid, salicylaldehyde, 2-oxyacetophenone, levulinic acid, salicylic acid, acetylacetone, brent catechin, 5-benzoazosalicylic acid, 2-acetyl-1,4-cresol , 6-acetyl-1,3-cresol, dibenzoylmethane, 8-oxyquinoline and the like.

Furthermore, as a chelating agent, 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; Ethylethylenediaminetriacetic acid, its potassium salt, its sodium salt; Nitrilotriacetic acid, its potassium salt, its sodium salt; 2-diaminocyclohexanetetraacetic acid, its potassium salt, its sodium salt; 1,3
-Aminopolycarboxylic acids such as diamino-2-propanoltetraacetic acid, its potassium salt, and its sodium salt, and 2-phosphonobutanetricarboxylic acid-1,2,4,
Its potassium salt, its sodium salt; 2-phosphonobutanetricarboxylic acid-2,3,4, its potassium salt, its sodium salt; 1-phosphonoethanetricarboxylic acid-1
, 2, 2, its potassium salt, its sodium salt; 1-hydroxyethane-1,-diphosphonic acid, its potassium salt, its sodium salt; aminotri(methylenephosphonic acid), its potassium salt, its sodium salt; Examples include phosphonic acids and phosphotricarboxylic acids.

The content of the chelating agent in the developer is 0.01
A range of 2.0% by weight is preferred.

[0030] The present invention provides a developer solution and a developer replenisher containing (A)
Alkali silicate, (B) surfactant, (C) organic solvent,
(D) A reducing agent and (E) a chelating agent are contained, and the above (
The concentration ratio of at least one of A) to (E) is made different between the developer and the developer replenisher.

In the present invention, the above (A) to
As mentioned above, the preferable range of each concentration of (E) is as follows: (A)
(B) is 0.3 to 10% by weight, and (B) is 0.01 to 10% by weight.
, (C) is 0.05 to 10% by weight, and (D) is 0.1 to 2% by weight.
0% by weight, (E) is 0.01 to 2.0% by weight, and the preferred concentration range of the above (A) to (E) in the developer replenisher is 0.5 to 10% by weight, (B) is 0.05 to 15
% by weight, (C) is 0.05-10% by weight, (D) is 0.05% by weight.
5 to 30% by weight, and (E) 0.01 to 2.0% by weight. In the present invention, A
) alkali silicate, (B) surfactant, (C) organic solvent, (D) reducing agent, and (E) chelating agent at concentrations,
The concentration ratio of at least one of the above (A) to (E) is made different between the developer and the developer replenisher, but the concentration ratio of the above (A) to (E) is different between the developer and the developer replenisher. Preferred embodiments for changing are as follows. (2) Increase the concentration ratio of the surfactant in the developer replenisher than in the developer.

(2) The concentration ratio of the reducing agent is made higher in the developer replenisher than in the developer.

[0033] The present invention uses a developer and a developer replenisher to
By changing the concentration ratio of A) to (E), one type of developer replenisher can be used, and the developer replenishment work and the developing device can be simplified. In the present invention, the developer replenisher is composed of one type of solution, but the present invention also includes a form in which a concentrated solution is used as the developer replenisher and diluted with water for dilution.

[0034] In addition to the above, the following additives can be added to the developer and developer replenisher used in the present invention in order to improve the development performance. For example, JP-A-58-75152
Neutral salts such as NaCl, KCl, KBr, etc. described in Japanese Patent Publication No. 1987-190952, EDTA, NTA described in Japanese Patent Application Laid-open No. 190952/1983
chelating agents such as, complexes such as [Co(NH3)]6Cl3 described in JP-A-59-121336, JP-A-59-121336, etc.
Ampholytic polymer electrolytes such as a copolymer of vinylbenzyltrimethylammonium chloride and sodium acrylate described in JP-A No. 142528, inorganic lithium compounds such as lithium chloride described in JP-A-58-59444, JP-B-50-34442 Organic lithium compounds such as lithium benzoate as described, organometallic surfactants containing Si, Ti, etc. described in JP-A-59-75255, JP-A-59-75255;
Organoboron compound described in JP-A-84241, JP-A-63
Examples include organic carboxylic acids described in JP-A-188142.

In the present invention, the pH of the developer replenisher is preferably higher than that of the developer. The pH of the developer is preferably 12.0 to 13.5, and the pH of the developer replenisher is preferably 12.3 to 13.8.

A preferred embodiment of the present invention is to vary the amount of replenishment depending on the processing ratio of the negative-working photosensitive lithographic printing plate and the positive-working photosensitive lithographic printing plate, as described above. Here, the processing ratio is the ratio of processing amount (specifically, area). The relationship between the processing ratio and the replenishment amount can be easily determined in advance through experiments.

In the present invention, the processing ratio of the positive-working photosensitive lithographic printing plate and the negative-working photosensitive lithographic printing plate may be set in advance throughout the day. That is, the processing rate throughout the day is scheduled in advance, and the average replenishment amount corresponding to this scheduled processing rate is replenished throughout the day, and the negative-working photosensitive lithographic printing plate and the positive-working photosensitive lithographic printing plate are refilled each time. Replenishment may be performed without making any difference in the amount of replenishment.

Further, in the present invention, the amount of replenishment of the developer replenisher may be adjusted depending on the processing area, number, longitudinal length (transport direction), etc. of the photosensitive planographic printing plates to be processed. Also,
Replenishment of the developer may be performed in response to fatigue caused by other than processing of the photosensitive planographic printing plate, such as replenishment over time.

The negative-working photosensitive lithographic printing plate treated by the method of the present invention has a photosensitive layer using a diazo compound as a photosensitive component, and the positive-working photosensitive lithographic printing plate has a photosensitive layer using an o-quinonediazide compound as a photosensitive component. For example, it is a photosensitive lithographic printing plate as described in JP-A-62-175757, page 5, lower left, line 18 to page 7, upper right column, line 11.

[0040]

[Examples] The present invention will be explained below with reference to Examples. Example 1 24 liters of the following developer was put into the developer tank 4 of an automatic processor shown in FIG. 1, and the developer replenisher (A) below was put into the developer replenisher tank 8.

Developer solution phenylpropylene glycol
0.04 parts by weight
Propylene glycol
2.00
〃 p-tert-butylbenzoic acid
0.57 〃 Emulgen 14
7
0.02 〃
(manufactured by Kao Corporation, nonionic surfactant,
polyoxyethylene lauryl ether)
Perex NBL

0.20 (manufactured by Kao Corporation,
Anionic surfactant, sodium alkylnaphthalene sulfonate 31% solution)
potassium hydroxide
1.30
〃 Potassium silicate aqueous solution
2
．． 10 〃 (SiO2
(containing 26% by weight, K2O content 13% by weight)
potassium sulfite
2.50 〃
Gluconic acid solution (50% aqueous solution)
0.50
〃 Triethanolamine
1.0
0 water

89.77 Developer replenisher (A) Phenylpropylene glycol
0.04 parts by weight
Propylene glycol
2.00
〃 p-tert-butylbenzoic acid
1.54 Emulgen 14
7
0.29 〃
potassium hydroxide
3.10 〃
Potassium silicate aqueous solution
(SiO2 content%, K2O content 13% by weight
) 5.58 〃
potassium sulfite
3.20 〃
Glyconic acid solution (50% aqueous solution)
0.41
〃 Triethanolamine
1.5
0 〃 Water

82.34 Next, thickness 0.24m
After degreasing a JIS-1050 aluminum plate in 2% aqueous sodium hydroxide solution, the surface was electrochemically roughened in a dilute nitric acid solution, thoroughly washed, and then immersed in a dilute sulfuric acid solution. 2.5g/m2 after anodizing
An oxide film was formed on the surface of the aluminum plate. After washing and drying the aluminum plate treated in this way, a photosensitive solution having the following composition was applied to give a dry weight of 2.5 g/m 2 and dried to obtain a positive-working photosensitive lithographic printing plate.

Composition of photosensitive coating liquid Ester compound of naphthoquinone-(1,2)-diazide-(2)-5-sulfonic acid chloride and pyrogallol acetone resin (described in Synthesis Example 2 of JP-A-60-143345) A copolycondensation resin of 2 parts by weight of phenol, m-, p-mixed cresol, and formaldehyde (the molar ratio of each of phenol, m-cresol, and p-cresol during synthesis was 20
:48:32, weight average molecular weight Mw = 7400, number average molecular weight Mn = 1400) 6.5 parts by weight Novolak resin synthesized from p-tert-octylphenol and formaldehyde and naphthoquinone-(1,2)-diazide-(2 )-ester compound with 5-sulfonic acid chloride (condensation rate: 50 mol%, M
w=1700) 0.1 parts by weight Victoria Pure Blue BOH (manufactured by Hodogaya Chemical Co., Ltd.) 0.08 parts by weight ethyl cellosolve

80 parts by weight methyl cellosolve

20 parts by weight A large number of positive photosensitive lithographic printing plates thus obtained were prepared, and a transparent positive film and a step tablet for sensitivity measurement (No. 2 manufactured by Eastman Kodak Company, 21 gray levels with a density difference of 0.15 each) were prepared. scale) and place a 2kW metal halide lamp (
Exposure was carried out for 60 seconds from a distance of 70 cm under conditions of 8.0 mW/cm 2 using an Idol Fin 2000 (manufactured by Iwasaki Electric Co., Ltd.) as a light source.

Furthermore, JIS-105 with a thickness of 0.24 mm
0 aluminum plate was immersed in a 20% sodium phosphate aqueous solution to degrease it, and then electrochemically roughened in a dilute hydrochloric acid solution.
After thorough washing, anodization treatment was performed in a dilute sulfuric acid solution to form an oxide film of 1.5 g/m2 on the surface of the aluminum plate. The aluminum plate thus treated was further immersed in an aqueous solution of sodium metasilicate for pore sealing, washed with water, and dried, after which a photosensitive solution having the following composition was applied to a dry weight of 2.0 g/m2. , and dried to obtain a negative photosensitive lithographic printing plate.

Photosensitive liquid composition Hexafluorophosphate of a condensate of p-diazizodiphenylamine and paraformaldehyde

1 part by weight N-(
4-Hydroxyphenylmethacrylamide copolymer (described in Example 1 of Japanese Patent Publication No. 57-43890)

10 parts by weight Victoria Pure Blue BOH (manufactured by Hodogaya Chemical Industry Co., Ltd., dye)

0.2 parts by weight
ethylene glycol monomethyl ether


100 parts by weight A large number of negative photosensitive lithographic printing plates thus obtained were prepared, and a transparent negative film and a step tablet for sensitivity measurement (No. 2 manufactured by Eastman Kodak Company, 21 gray levels with a density difference of 0.15 each) were prepared. 2kW metal halide lamp (idle fin 2000 manufactured by Iwasaki Electric Co., Ltd.)
) as a light source at 8.0 mW/cm2, 70 cm
Exposure was carried out for 30 seconds from a distance of .

Fifty positive photosensitive lithographic printing plates and 50 negative photosensitive lithographic printing plates thus obtained were randomly processed at 27° C. for 20 seconds using a prepared automatic processor. At this time, 50 ml of developer replenisher was added for every 1 m2 of photosensitive planographic printing plate processed. A total of 100 positive-working photosensitive planographic printing plates and negative-working photosensitive planographic printing plates were processed, and no difference was observed in the development quality between the first sheet and the last 100th sheet.

In FIG. 1, 1 is a developing section for performing development processing, 2 is a water washing section, 3 is a rinse/gum section for processing with a rinsing liquid or desensitizing liquid, 4 is a developing solution tank, and 5
7 to 7 are processing liquid supply nozzles, 8 is a developer replenisher tank, 9 to 12 are pumps, and S is a photosensitive lithographic printing plate or its transport path.

Example 2 10 positive-working photosensitive planographic printing plates and 90 negative-working photosensitive planographic printing plates were used, except that 45 ml of developer replenisher was added for every 1 m2 of photosensitive planographic printing plates processed. When an experiment similar to Example 1 was conducted, no difference was observed in the development quality between the first sheet and the last 100 sheets.

Experiment 1 Example except that 90 positive-working photosensitive planographic printing plates and 10 negative-working photosensitive planographic printing plates were used, and 55 ml of developer replenisher was added for every 1 m2 of photosensitive planographic printing plates processed. When the process was carried out in the same manner as in step 1, there was a difference in development quality between the first 1st sheet and the last 100th sheet.

Example 3 70 positive-working photosensitive planographic printing plates and 30 negative-working photosensitive planographic printing plates were used, except that 55 ml of developer replenisher was added for every 1 m2 of photosensitive planographic printing plates processed. When the same procedure as in Example 1 was carried out, no difference was observed in the development quality between the first sheet and the last 100th sheet.

Experiment 2 Example except that 30 positive-working photosensitive planographic printing plates and 70 negative-working photosensitive planographic printing plates were used, and 50 ml of developer replenisher was added for every 1 m2 of photosensitive planographic printing plates processed. When the process was carried out in the same manner as in step 1, there was a difference in development quality between the first 1st sheet and the last 100th sheet. Examples 1-3 and Experiment 1
FIG. 2 (graph) shows the relationship between the number of processed sheets of the positive-working SP plate and the negative-working photosensitive lithographic printing plate of No. 2 and the relationship between the amount of developer replenisher and the development quality. This graph shows that the development quality can be kept stable by changing the development replenishment amount at a constant rate depending on the processing ratio of the positive-working photosensitive lithographic printing plate and the negative-working photosensitive lithographic printing plate.

Comparative Example 1 Developer replenisher (B) Phenylpropylene glycol
0.04 parts by weight
Propylene glycol
2.0
〃 p-tert-butylbenzoic acid

0.57 〃 Emulgen 147

0.02 〃 Potassium hydroxide
7.80 〃
Potassium silicate aqueous solution
2.10 〃
(SiO2 content 26% by weight, K2
O content 13% by weight) Potassium sulfite

2.20 Glyconic acid solution (50% aqueous solution)
0.50 Triethanolamine
1.00 〃
water
89
．． 67 Same as Example 1, using the developer replenisher (B) above, using the same developer, automatic processor, positive photosensitive lithographic printing plate, and negative photosensitive lithographic printing plate as in Example 1. was processed. In Example 1, stable development quality was obtained by adding 50 ml of replenisher (A) for every 1 m2 of photosensitive lithographic printing plate processed, but it was not possible to obtain stable development quality with replenisher (B). I could not find the amount of replenisher that could be added. Example 4 The same experiment as in Example 1 was conducted except that the automatic developing machine shown in FIG. 3 was used, and as a result, the development quality could be stably maintained.

In FIG. 3, 31 is a developing section for performing development processing, 32 is a washing section, 33 is a rinse/gum section for processing with a rinsing liquid or desensitizing solution, 34 is a developing tank, and 35 is a developing replenisher. A tank, 36 to 39 are pumps, 40 and 41 are shower nozzles, and S is a photosensitive lithographic printing plate or its transport path.

[0053]

According to the present invention, in a processing method in which a negative-working photosensitive lithographic printing plate and a positive-working photosensitive lithographic printing plate are developed with a common developer that is repeatedly used after replenishing a replenisher,
The development quality can be stably maintained, and the development replenishment method and the apparatus used therein can be simplified.

[Brief explanation of the drawing]

Figures 1 and 3 are cross-sectional views showing an example of the apparatus used in the examples, and Figure 2 is the processing ratio and development replenishment amount of the negative photosensitive lithographic printing plate and the positive photosensitive lithographic printing plate in the example. It is a graph showing the relationship between

[Explanation of symbols]

1, 31...Developing section 2, 32...
・Water washing section 3, 33... Rinse gum section 4...
Developer tank 8, 35...Developer replenisher tank 34...Developer tank

Claims (2)

[Claims] Claim 1: A development process in which a negative-working photosensitive lithographic printing plate and a positive-working photosensitive lithographic printing plate are developed using an automatic developing machine with a developing solution that can be used repeatedly for negatives and positives by replenishing a developer replenisher. In the method, the developer and the developer replenisher contain an alkali silicate, a surfactant, an organic solvent, a reducing agent, and a chelating agent, the alkali silicate, the surfactant,
A method for processing a photosensitive lithographic printing plate, characterized in that the developer replenisher is different from the developer in the concentration ratio of an organic solvent, a reducing agent, and a chelating agent, and the developer replenisher is composed of one type of solution. 2. The processing method according to claim 1, wherein the method for replenishing the developer replenisher changes the amount of replenishment depending on the processing ratio of the negative-working photosensitive lithographic printing plate and the positive-working photosensitive lithographic printing plate.