JPH0391750A - Processing method for photosensitive planographic plate - Google Patents

Abstract

PURPOSE:To maintain the development quality of a positive PS plate stably by adjusting the content of a surface active agent in supplementary liquid according to the processing rate of a negative photosensitive planographic plate and a positive photosensitive planographic plate. CONSTITUTION:An automatic developing machine is used to develop the negative and positive photosensitive planographic plates with an alkali negative-positive common liquid developer which is used repeatedly and used water as a solvent. When the activity of the liquid developer which deteriorates i the development processing is compensated by adding the supplementary liquid, the content of the surface active agent in the supplementary liquid is adjusted according to the processing rate of the negative and positive photosensitive planographic plates. The content of the surface active agent in the supplementary liquid is adjusted by preparing for the supplementary liquid and a surface active agent solution individually and varying their mixing rate. This method stably maintains the development quality as to both the negative PS late and positive PS plate.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a photosensitive lithographic printing plate (referred to as a "PS plate").
Regarding the processing method, in more detail, the negative-tone PS plate and the positive-tone PS plate are refilled with replenisher using an automatic developing machine and the negative and positive PS plates are processed.
The present invention relates to a processing method of developing with a positive common developer.

[Conventional technology]

Conventionally, in the method of developing a negative PS plate and a positive PS plate by replenishing a replenisher with a common developer for the negative PS plate and positive PS plate using I automatic developing machines, P
It was necessary to include an organic solvent in the developer before developing the S plate, but at the same time there was a problem in that the image area of the positive PS plate was attacked.

It has been known to add a surfactant to the developing solution as a means to solve this problem, but when developing while adding a replenisher, there is a difference between processing a negative PS plate and a positive PS plate. Since the amount of surfactant consumed during processing differs, depending on the processing ratio of the negative PS plate and the positive PS plate, the concentration of surfactant in the developer may decrease, causing the image area of the positive PS plate to decrease. There was a problem that the surfactant was attacked or the concentration of the surfactant became excessive, which inhibited the developability of the positive type PS plate.

[Purpose of the invention]

The purpose of the present invention is to develop a negative PS plate and a positive PS plate by replenishing a replenisher with a common negative/positive developer.
An object of the present invention is to provide a processing method that can stably maintain the development quality of a positive type PS plate.

[Structure of the invention]

The above-mentioned object of the present invention is to produce an alkaline negative film containing water as the main solvent by using an automatic developing machine to process a negative-working photosensitive lithographic printing plate and a positive-working photosensitive lithographic printing plate in the same repeated manner.
In a method for processing a photosensitive lithographic printing plate in which a photosensitive lithographic printing plate is developed with a common developer and a replenisher is added to compensate for the decreased activity of the developer due to the development process, a negative photosensitive lithographic printing plate and a positive photosensitive lithographic printing plate are used. This is achieved by a method for processing a photosensitive lithographic printing plate, which is characterized in that the content of the surfactant in the replenisher is adjusted depending on the processing ratio with the photosensitive lithographic printing plate. In addition, the present invention provides a method for adjusting the surfactant content in the replenisher solution in the above treatment method, in which the replenisher solution and the surfactant solution are prepared separately, and the content is adjusted by changing the mixing ratio of the replenisher solution and the surfactant solution. It is characterized by this.

The present invention will be explained in detail below.

The developer used in the present invention has water as its main solvent (
Specifically, it is an alkaline negative/positive common developer (in which 50% by weight or more of the solvent is water).

The composition contains organic solvents and surfactants in addition to alkaline agents.

The developer of the present invention contains 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 developing solution is preferably in the range of 0.3 to IO% by weight.

In addition, alkali silicate is S10. The concentration is O. l~7,0
A weight percent range is preferred.

Alkali agents other than alkali silicates 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, tribasic potassium phosphate, dibasic potassium phosphate, tribasic ammonium phosphate, dibasic ammonium phosphate, sodium metasilicate, bicarbonate Inorganic alkaline agents such as sodium, 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 pH of the developer is preferably 12 or higher, more preferably 1.
It is in the range of 2.5 to 13.5.

The organic solvent contained in the developer according to the present invention is 20
The solubility in water at '0 is preferably IO% by weight or less, such as carboxylic acid esters such as ethyl acetate, probyl acetate, butyl acetate, benzyl acetate, ethylene glycol monobutylacetate, butyl lactate, and butyl levulinate. Ketones such as ethyl butyl ketone, methyl isobutyl ketone, cyclohexanone: ethylene glycol monobutyl ether, ethylene glycol benzyl ether, ethylene glycol monophenyl ether, vecinoreal alcohol, notinol 7-enyl carbinol, n- Alcohols such as amyl alcohol and methylamine alcohol; alkyl-substituted aromatic hydrocarbons such as xylene; halogenated hydrocarbons such as methylene dichloride, ethylene dichloride, and monochlorobenzene. 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 IO% by weight.

The surfactant contained in the developer in the present invention may be nonionic, cationic, anionic, or amphoteric, but is preferably a nonionic surfactant or a cationic surfactant, and more preferably a nonionic surfactant. .

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 them, ethyleneoxy group (-
CH2CH,O-) is 3 or more, and HLB value (
HLB is Hydrophile-Lipopbile
Balance) is 5 or more (more preferably 8 to 2)
0. More preferably, the nonionic surfactants 15 to 20) are more preferred.

Furthermore, among nonionic surfactants, those having both an ethylene group and a propylene oxy group are particularly preferable, and among these, those having an HLB value of 8 or more are more preferable.

As a preferable example of the nonionic surfactant, the following general formula [l
] to [8] are mentioned.

(1) R-0- (CHx01.O)nH[3
] R-0 (CHzCHO)m (C}IzCHzO)nH[6
] Ho(C,H40)a − (C,H.O)b − (
Czl{ao)cHC8) I{O-(α{zcH2
0) nu In the formulas (1) to [8], R represents a hydrogen atom or a l-valent organic group. Examples of the organic group include a linear or branched alkyl group having 1 to 30 carbon atoms that may have a substituent {for example, an aryl group (phenyl, etc.)};
Examples thereof include an alkylcarbonyl group in which the alkyl moiety is the above alkyl group, a phenyl group which may have a substituent (for example, a hydroxyl group, an alkyl group as described above, etc.). a1b, c, m, n, x and y each represent an integer of 1 to 40.

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 oxyethylene polyoxypropylene behenyl ether,
Polyoxyethylene nonyl 7-enyl ether, polyoxyethylene octylphenyl ether, polyoxyethylene stearylamine, polyoxyethylene oleylamine, polyoxyethylene stearic acid amide, polyoxyethylene oleic acid amide, polyoxyethylene castor oil, polyoxyethylene abi Ethyl ether, polyoxyethylene lanolin ether, polyoxyethylene monolaurate, polyoxyethylene monostearate, polyoxyethylene glycol monostearate, polyoxyethylene propylene glycol monostearate, oxyethylene oxybrobylene block polymer
distyrenated phenol polyethylene oxyto 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 300 to 100
The range of 00 is preferred, and the range of 500 to 5000 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 anolekylamine, N-alkylpropylene amine, N-lyethylenebolyamine dimethyl sulfate, alkyl biguanide, long-chain amine oxide, alkylimidazoline, l-hydroxyethyl-2-alkylimidazoline, -acetylaminoethyl-2-alkylimidazoline, 2-alkyl-4-methyl-4-hydroxymethyloxazoline, and the like.

Examples of quaternary ammonium salts include long-chain primary amine salts, alkyltrimethylammonium salts, dialkyldimethylethylammonium salts, alkyldimethylammonium salts, alkyldimethylbenzylammonium salts, alkylpyridinium salts, and alkylquinolinium salts. , alkylisoquinolinium salt, alkylpyridinium sulfate, stearamidemethylpyridinium salt, acylaminoethyldiethylamine salt, acylaminoethylmethyldiethylammonium salt, alkylamidoprobyldimethylbenzylammonium salt, fatty acid polyethylene polyamide, Acylaminoethylpyridinium salt, acylcolaminoformylmethylpyridinium salt, stearoxymethylpyridinium salt, fatty acid triethanolamine, fatty acid triethanolamine formate, 1-lyoxyethylene fatty acid triethanolamine, fatty acid dibutylamino Ethanol, cetyloxymethylpyridinium salt,
Examples include p-yneoctylphenoxyethoxyethyldimethylbenzyl ammonium salt. ("Alkyl" in the above compound examples refers to straight chain or partially substituted alkyl having 6 to 20 carbon atoms, specifically hexyl,
Straight chain alkyls such as octyl, cetyl and stearyl are preferably used. ) Among these, water-soluble quaternary ammonium salt type cationic surfactants are particularly effective, and among these, anolequinoletrimethylammonium salts, alkyldimethylbenzyl ammonium salts, ethylene oxide addition ammonium salts, etc. are preferred. In addition, polymers having repeating monotonous monomers are also cationic surfactants in a broad sense, and are included in the cationic surfactants 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 in the range of 500 to 5,000.

These cationic surfactants can be used alone or in combination with
You may use more than one species in combination.

As anionic surfactants, higher alcohols (CS
~C22) Sulfuric ester salts [e.g., sodium salt of lauryl alcohol sulfate, sodium salt of octyl alcohol sulfate, ammonium salt of lauryl alcohol sulfate, r Teepol-81J
(trade name, manufactured by Shell 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 (
For example, the sodium salt of dodecylbenzenesnolephonic acid, the sodium salt of inglovirnaphthalenesulfonic acid,
sodium salt of dinaphthalene disulfonic acid, sodium salt of metanitrobenzenesulfonic acid, etc.), sulfonate salts of alkylamides (for example, C+yH3!CON)
(CHs)Cf{zsOJa, etc.), 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.

As the amphoteric surfactant, for example, a compound such as sodium N-methyl-N-pentadecylaminoacetate can be used.

The surfactant is added to the developer at a concentration of 0. It is preferable to contain it at a concentration in the range of OI to 10% by weight.

The developer according to the present invention can contain a reducing agent. As the reducing agent, 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, ammonium sulfite, and hydrogen sulfite. Sulfites such as sodium and potassium hydrogen sulfite, sodium phosphite, potassium phosphite, sodium hydrogen phosphite,
Examples include phosphates such as potassium hydrogen phosphite, sodium dihydrogen phosphite, and dipotassium hydrogen phosphite, hydrazine, sodium thiosulfate, and sodium dithionite, which are particularly effective in the present invention. The reducing agent used is sulfite.

The reducing agent can be contained in the developer in an amount of 0.1 to 20% by weight.

The developer according to the present invention can contain an organic carboxylic acid.

Organic carboxylic acids include aliphatic carboxylic acids having 6 to 20 carbon atoms, and aromatic carboxylic acids in which a benzene ring or a naphthalene ring is substituted with a carpoxyl group.

The aliphatic carboxylic acid is preferably an alkanoic acid having 6 to 20 carbon atoms, and specific examples include caproic acid, enantylic acid, cabrylic acid, pelargonic acid, cabric acid, lauric acid, mystylic acid, palmitic acid, and stearic acid. etc., and particularly preferred are alkanoic acids having 6 to 12 carbon atoms. Also, fatty acids with double bonds in their carbon chains,
It may also have a branched carbon chain. The above aliphatic carboxylic acid may be used as a sodium or potassium salt or an ammonium salt.

Specific compounds of aromatic carboxylic acids include benzoic acid, 0-chlorobenzoic acid, p-chlorobenzoic acid, 0-hydroxybenzoic acid, p-hydroxybenzoic acid, p-ter
t-Butylbenzoic acid, 0-aminobenzoic acid, p-aminobenzoic acid, 2,4-dihydroxybenzoic acid, 2,5-dihydroxybenzoic acid, 2,3-dihydroxybenzoic acid, 2
, 3-dihydroxybenzoic acid, 3.5-dihydroxybenzoic acid, gallic acid, l-hydroquine-2-naphthoic acid,
3-hydroxy-2-naphthoic acid, 2-hydroxy-1
-naphthoic acid, l-naphthoic acid, 2-naphthoic acid, etc.

The above-mentioned aromatic carboxylic acid may be used as a sodium or potassium salt or an ammonium salt.

There are no particular restrictions on the content of aliphatic carboxylic acid and aromatic carboxylic acid, but the content is 0. If it is less than 1% by weight, the effect will not be sufficient, and if it is more than 30% by weight, not only will the effect not be improved any further, but it may also hinder dissolution when other additives are used together. Therefore, the amount added is preferably (Ll-10% by weight), more preferably 0.5 to 4% by weight.

In addition to the above, the following additives can be added to the developer used in the present invention in order to improve the development performance. For example, NaC (2,
Neutral salts such as KCQ, KBr, etc., JP-A-59-19095
Chelating agents such as EDTA and NTA described in Publication No. 2, (Co(NHx) described in JP-A-59-121336)
) complexes such as ecl2s, amphoteric polymer electrolytes such as the copolymer of vinylbenzyltrimethylammonium chloride and sodium acrylate described in JP-A-56-142528, lithium chloride as described in JP-A-58-59444, etc. Inorganic lithium compound, Special Publication No. 50-34442
Organolithium compounds such as lithium benzoate described in JP-A-59-75255, Si. Organometallic surfactants containing Ti etc., organoboron compounds described in JP-A-59-84241, JP-A-63-188142
Examples include organic carboxylic acids described in the above publication.

The replenisher of the present invention has a structure that compensates for the activity (development performance) of the developer that decreases due to development processing by adding it to the developer (development mother solution) to be refilled. It is fine as long as you have it. A preferred embodiment is one in which the alkaline activity (pH) of the replenisher is equal to or higher than that of the developing mother solution. Specifically, it is preferable that the pH of the developer replenisher is 0.0 to 1.0 higher than the pH of the developer. Further, it is preferable that the method for replenishing the developer in the present invention compensates for both fatigue due to development processing and fatigue due to aging.

In the present invention, the means for adjusting the concentration of surfactant in the replenisher is optional. For example, the replenisher can be divided into two solutions having different surfactant concentrations (for example, one solution is suitable for negative-tone PS plates). A method can be used in which the concentration of the liquid is divided into two liquids (one liquid has a concentration suitable for a positive type PS plate, the other liquid has a concentration suitable for a positive type PS plate, etc.), and the mixing ratio is used. A preferred method is to prepare a surfactant solution separately from the replenisher and adjust the concentration of surfactant in the replenisher by changing the mixing ratio of this surfactant solution and the replenisher. Can be mentioned. In this case, the surfactant solution is preferably an aqueous solution.

The replenisher in the present invention is preferably prepared as a concentrated solution and diluted with water before use from the viewpoint of preparation efficiency and transport efficiency of the replenisher.

In the present invention, as mentioned above, the concentration of surfactant in the replenisher is changed depending on the processing ratio of the negative PS plate and the positive PS plate. (specifically, the area). The relationship between the treatment ratio and the concentration of surfactant in the replenisher can be easily determined in advance through experiments.

The timing for adjusting the concentration of surfactant in the replenisher is determined by planning in advance the processing ratio of positive PS plate and negative PS plate throughout the day, and replenishing the average concentration of surfactant corresponding to this planned processing ratio. You can replenish it with liquid throughout the day.

In the present invention, the amount of replenisher to be refilled depends on the processing area, number of PS plates to be processed, length (transfer direction), etc.
It may be divided into sections.

PS plates suitable for processing in the method of the invention include negative-tone P
The S plate has a photosensitive layer using a diazo compound as a photosensitive component, and the positive PS plate has a photosensitive layer using an 0-quinonediazide compound as a photosensitive component, for example, JP-A-62-175757. Includes PS versions as described in page 5, lower left column, line 18 to page 7, upper right column, line 11.

〔Example〕

The present invention will be explained below with reference to Examples.

3 parts by weight of esterified product of na7toquinone-1,2-diazido-5-sulfonyl chloride and resorcinol-benzaldehyde resin (described in Example 1 of JP-A-56-1044), 91 tons of cresol nopolac resin A photosensitive solution was prepared by dissolving 0.12 parts by weight of Victoria Pure Blue BOH (manufactured by Hodogaya Chemical Industry Co., Ltd., dye) in 100 parts by weight of methyl cellosol. Thickness 0
．． A grained aluminum plate of 3r++i was anodized in sulfuric acid to form an oxide film of 2.7 g/m'', washed thoroughly and dried, and the above photosensitive solution was applied on it and dried.
A PS plate having a photosensitive layer of approximately 2.4 g/m" was obtained. The positive type PS plate thus obtained was 1003 mm x 8
A large number of sheets cut to a size of 0.00 mm were prepared and exposed through a transparent positive for 60 seconds from a distance of 80 cm using a 2 kW methyl halide lamp.

On the other hand, a negative PS plate was produced as follows.

A grained aluminum plate with a thickness of O - 24 mm was anodized in sulfuric acid to form an oxide film of approximately 1.5 g/m'', and after being thoroughly washed, it was immersed in a sodium silicate aqueous solution, thoroughly rinsed with water, and then dried. A photosensitive solution having the following composition was applied.

Photosensitive liquid A copolymer of p-hydroxy 7enylmethacrylamide, acrylonitrile, ethyl acrylate, and methacrylic acid (molar ratio in the above order: 8.5: 24: 60.5:
7) 5.0 parts by weight Hexafluorophosphate, a condensate of p-diazodiphenylamine and paraformaldehyde 0.5 parts by weight Victoria Pure Blue BOH (manufactured by Hodogaya Chemical Co., Ltd., dye) O, The coating amount after drying was 1.8 g/m'' after drying 100 parts by weight of ethylene glycol monomethyl ether.

The negative PS plate obtained in this way was
Prepare a large number of pieces cut to a size of 1003mm,
These were exposed through a transparent negative for 50 seconds from a distance of 80 cm using a 2 kW metal halide lamp.

Next, the following composition developer concentrate was prepared.

Development concentrate Ethylene glycol mono-7enyl ether 3 parts by weight Benzoic acid 65 parts by weight 50%
Sodium hydroxide aqueous solution 150 parts by weight Emulgen 130K 2 parts by weight (manufactured by Kao Corporation, nonionic surfactant) Sodium silicate aqueous solution 140 parts by weight (JIS standard sodium silicate No. 3) 40% sodium sulfite aqueous solution 260 parts by weight Water
550 parts by weight 1st
A developer solution 24Q, which is a mixture of the developer concentrate and water at a ratio of 1:5, is charged into the developer tank 5 of the automatic developing machine shown in the figure.
The developer temperature was adjusted to 27°C. In addition, a concentrated developer replenisher of the following composition was prepared as F4.

Concentrated developer replenisher A Ethylene glycol monophenyl ether lO parts by weight Benzoic acid 90 parts by weight 50% aqueous sodium hydroxide solution 300 parts by weight Emulgen 1
30K 1.3 parts by weight (Kao Corporation)
(nonionic surfactant) sodium silicate aqueous solution
240 parts by weight (JIS standard sodium silicate No. 3) 40% aqueous sodium sulfite solution 150 parts by weight Water
320 parts by weight Concentrated developer replenisher B Emulgen 130K 13.7 parts by weight (manufactured by Kao Corporation, nonionic surfactant) Water
The conveyance speed of the 100 parts by weight automatic developing machine was set so that the developing time was 20 seconds,
The amount of developer replenisher to be refilled is 50 m per negative PS plate 1 process.
Q, 70 ra for each positive PS plate 1 treatment (1, 1 Q + Q per minute for the shower operating time, 1 Q @ 12 per hour for replenishment over time when the shower is stopped). The developer replenisher is a mixture of concentrated developer replenisher and water at a ratio of 1=3 in the developer tank 5.
I decided to replenish it. Next, add water 1 to the flush water tank 6.
A mixture of SGW-2 (gum liquid manufactured by Konica Corp.) and water at a ratio of 1:1 was added to Gum Liquid Sampler 7.

Example 1 The concentrated developer replenisher A was charged into the concentrated developer replenisher tank 8, and after 100 plates of the negative PS plate were continuously processed under the above processing conditions, the positive PS plate was processed. The lithographic printing plate thus obtained (obtained by developing a positive PS plate) was inked using SPO-1 (development ink manufactured by Konica Corporation), but the non-image areas were filled with ink. No staining occurred, and no defective inking occurred in the image area.

Example 2 A mixture of the concentrated developer replenishers A and B at a ratio of 10:1 was charged into the concentrated developer replenisher tank 8, and after 100 positive PS plates were continuously processed under the above processing conditions. ,
The positive PS plate was processed. The lithographic printing plate thus obtained (the 101st plate) was inked using SP011, but no background staining occurred in the non-image area.
There were no defects in inkling in the image area.

Example 3 A concentrated developer replenisher tank 8 was charged with a mixture of the concentrated developer replenishers A and B at a ratio of 10:0.5, and the positive PS plate and the negative PS plate were processed under the above processing conditions. l
After a total of 100 plates were processed alternately at a ratio of :1, the positive PS plate was processed. The lithographic printing plate thus obtained (1
When inking was applied to the 01st edition) using SPO-1, no scumming occurred in the non-image areas, and no defective inking occurred in the image areas.

Example 4 The same process as in Example 3 was performed except that after 50 plates of the negative PS plate were continuously processed, 50 plates of the positive PS plate were processed continuously. Of the lithographic printing plates thus obtained, all of the plates obtained from the above-mentioned positive type PS plate were inked using SPO-1, but no scumming occurred in the non-image areas, and no staining occurred in the image areas. No defective fleshing occurred.

Comparative Example 1 The same process as in Example 1 was performed except that the positive PS plate and the negative PS plate were alternately treated at a ratio of 1:1 for a total of 100 plates, and then the positive PS plate was treated. .

The lithographic printing plate thus obtained (101st edition) has S
When inking was performed using PO-1, poor inking occurred in the image area.

Comparative Example 2 The positive PS plate and the negative PS plate were alternately treated at a ratio of 1:1 for a total of 100 plates, and then the same process as in Example 2 was performed except that the positive PS plate was treated. .

The lithographic printing plate (lot number) obtained in this way has S
When ink was applied using PO-1, scumming occurred in non-image areas.

〔Effect of the invention〕

According to the present invention, in a processing method in which a negative PS plate and a positive PS plate are developed with a common developer that is repeatedly used by replenishing a replenisher, the development quality of both the negative PS plate and the positive PS plate is improved. can be maintained stably.

[Brief explanation of drawings]

The vgl diagram is a sectional view of the automatic developing machine used in the example. ■...Developing section 2...Water washing section 3... Gum pulling part 8...Developer replenisher tank 9... Dilution water tank

Claims (2)

[Claims] (1) Using an automatic developing machine, develop the negative-working photosensitive lithographic printing plate and the positive-working photosensitive lithographic printing plate with the same alkaline negative/positive common developer containing water as the main solvent, which is used repeatedly; In a method for processing a photosensitive lithographic printing plate in which the activity of the developer that decreases due to the development process is compensated for by adding a replenisher, the processing ratio of the negative-working photosensitive lithographic printing plate and the positive-working photosensitive lithographic printing plate is A method for processing a photosensitive lithographic printing plate, which comprises adjusting the content of a surfactant in the replenisher. (2) Claim (1) characterized in that a replenisher solution and a surfactant solution are prepared separately, and the content of surfactant in the replenisher solution is adjusted by changing the mixing ratio. processing method.