JP2876148B2 - Processing method and processing apparatus for photosensitive lithographic printing plate - Google Patents

Description

The present invention relates to a method for developing a photosensitive lithographic printing plate (hereinafter, referred to as a "PS plate"), and more particularly, to a developing method using an automatic developing machine. Replenish replenisher and use repeatedly
The present invention relates to a replenishing method and a replenishing device for a developer in a method of performing a common development process on a negative PS plate and a positive PS plate with a positive common developer.

[Conventional technology]

When a PS plate is developed using an automatic developing machine, a method of replenishing a developer with a replenisher and repeatedly using the developer or a method of disposing of the developer is known.

In the former method, due to the problem of accuracy and stability of replenishment,
In fact, it has been impossible to process a large number of sheets for a long period of time.
On the other hand, the method of disposing of a new liquid allows processing of a large number of sheets for a long period of time, but has a drawback that a large amount of a developer is used and processing cost is high.

By the way, a negative PS plate using a diazo compound as a photosensitive component and a positive PS plate using a quinonediazide compound as a photosensitive component are repeatedly used in one automatic processor to replenish the replenisher and use the negative PS plate repeatedly. As a replenishment technique of the developer in the developing method in which the common development is performed with the positive common developer,
JP-A-62-73271 discloses a technique for stabilizing developability during repeated use by using a replenisher containing a silicate having a higher alkali strength than the replenished developer, and dividing the replenisher into two solutions. One is an alkali solution containing a silicate and the other is a solution containing an anionic surfactant, a sulfite and an organic solvent.
A technique of changing the ratio of the replenishing amount of the liquid to replenish the liquid is disclosed. Japanese Patent Application Laid-Open No. Sho 62-55658 discloses a method for processing a photosensitive lithographic printing plate in which a developing process is performed by an automatic developing machine using a plurality of different developing solutions, and a different replenisher is replenished for each developing solution. Japanese Patent Application Laid-Open No. 63-100460 discloses a method for processing a photosensitive material using an automatic developing machine having two continuous developing zones, wherein one of the two developing zones is developed with a substantially unused developer. In the other development zone, a processing method of developing with a developer used repeatedly is disclosed.

[Problems to be solved by the invention]

However, even if the developing ability is kept constant by the technique disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 62-73271 and the technique of dividing the developing replenisher into two solutions, the quality such as gradation gradually deteriorates. There is a disadvantage. In addition, JP
The technology disclosed in Japanese Patent Application No. 55658/1988 and Japanese Patent Application Laid-Open No. 63-100460 has a disadvantage that the manufacturing cost of the processing apparatus is increased.

Accordingly, an object of the present invention is to provide a PS plate developing method in which an automatic developing machine is used, and a replenisher is replenished and developed with a negative / positive common developer that is repeatedly used. Another object of the present invention is to provide a processing method and a processing apparatus capable of performing common negative / positive processing at low cost without exchanging liquid.

[Means for solving the problem]

An object of the present invention is a method for processing a negative photosensitive lithographic printing plate and a positive photosensitive lithographic printing plate in one development zone using one kind of a common negative / positive developer which is repeatedly used. Detecting the activity of the developer, which decreases due to processing fatigue, by using different detection means depending on the type of plate, and compensating by adding one type of development replenisher in an amount corresponding to each type. The lithographic printing plate processing method, the means for processing in one development zone using one type of developer, and the plate types of the negative photosensitive lithographic printing plate and the positive photosensitive lithographic printing plate were made to correspond to each. This is achieved by a processing apparatus having different detection means, and having a function of detecting processing fatigue using the detection means and replenishing one type of replenisher in an amount corresponding to each of the detection means.

 Hereinafter, the present invention will be described in detail.

The present invention uses a single type of developing replenisher, and uses a detecting means (for example, a negative type PS plate) in which the activity of the developing solution, which decreases due to processing fatigue, differs depending on the type of plate (for example, a negative type PS plate and a positive type PS plate).
The plate area is detected for the plate, the elution degree of the non-image part is detected as impedance for the positive PS plate, etc.), and the amount is replenished according to each plate type. Appropriate replenishment is possible for each type of plate, and the replenisher is replenished to improve the effect of maintaining appropriate developability for long-term and large-number processing with a repeatedly used negative / positive common developer. It was done.

The negative-positive developer used in the method of the present invention and the replenisher thereof are mainly composed of water containing at least two selected from alkali silicates, organic solvents, surfactants and reducing inorganic salts ( Specifically, an alkali developing solution having a pH of 12 or more (50% by weight or more of water) is preferable.

Examples of the alkali silicate include potassium silicate, sodium silicate, sodium metasilicate, potassium metasilicate, and ammonium silicate. The content of the alkali silicate in the developer is preferably in the range of 0.3 to 10% by weight. The alkali silicate preferably has a SiO ₂ concentration in the range of 0.1 to 7.0% by weight.

Alkali agents other than alkali silicate can be used in combination in the developing solution and the developing replenisher. For example, potassium hydroxide, sodium hydroxide, lithium hydroxide, tribasic sodium phosphate, dibasic sodium phosphate, Inorganic alkali agents such as potassium phosphate, potassium phosphate dibasic, ammonium phosphate tribasic, ammonium phosphate dibasic, sodium metasilicate, sodium bicarbonate, sodium carbonate, potassium carbonate, ammonium carbonate, etc., mono, di or Organic alkaline agents such as triethanolamine and tetraalkyl hydroxide can be used in combination.

As the organic solvent, those having a solubility in water at 20 ° C. of 10% by weight or less are preferable, and examples thereof include carboxylic acids such as ethyl acetate, propyl acetate, butyl acetate, benzyl acetate, ethylene glycol monobutyl acetate, butyl lactate, and butyl replate. Acid esters; ketones such as ethyl butyl ketone, methyl isobutyl ketone and cyclohexanone; ethylene glycol monobutyl ether, ethylene glycol benzyl ether, ethylene glycol monophenyl ether, benzylasacol, methylphenylcarbinol, n-amyl alcohol, methyl amyl alcohol Alcohols such as xylene; alkyl-substituted aromatic hydrocarbons such as xylene; methylene dichlorite;
Examples include halogenated hydrocarbons such as ethylene dichloride and monochlorobenzene. These organic solvents can be used alone or in combination of two or more.

As the surfactant, at least one of nonionic, anionic, cationic and amphoteric surfactants can be used. Preferably, it is a nonionic surfactant.

Nonionic surfactants can be broadly classified into a polyethylene glycol type and a polyhydric alcohol type, and both can be used. From the viewpoint of developing performance, a polyethylene glycol type nonionic surfactant is preferable, and among them, an ethyleneoxy group is preferable. And the HLB value (HLB is Hydro
Nonionic surfactants having an ophile-Lipophile Balance of 5 or more (more preferably 8 to 20) are more preferred.

Among the nonionic surfactants, those having both an ethyleneoxy group and a propyleneoxy group are particularly preferable, and among them, those having an HLB value of 8 or more are more preferable.

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

In the formulas [1] to [8], R represents a hydrogen atom or a monovalent organic group. Examples of the organic group include a linear or branched alkyl group having 1 to 30 carbon atoms which may have a substituent {for example, an aryl group (such as phenyl)}, and an alkylcarbonyl in which the alkyl moiety is the above-mentioned alkyl group. And a phenyl group which may have a group and a substituent (for example, a hydroxyl group and the above-described alkyl group).
a, b, c, m, n, x and y each represent an integer of 1 to 40.

 The specific example of a nonionic surfactant is 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, polyoxy Ethylene polyoxypropylene behenyl ether,
Polyoxyethylene nonyl phenyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene stearylamine, polyoxyethylene oleylamine, polyoxyethylene stearamide, polyoxyethylene oleamide, polyoxyethylene castor oil, polyoxyethylene aviethyl Ether, polyoxyethylene lanolin ether, polyoxyethylene monolaurate, polyoxyethylene monostearate, polyoxyethylene glyceryl monostearate, polyoxyethylene glycer monostearate, polyoxyethylene propylene glycol monostearate, oxyethylene oxypropylene Block polymer, distyrenated phenol polyethylene oxide adduct, tribenzylphenol Ethylene oxide adducts, octyl phenol polyoxyethylene polyoxypropylene adduct, glycerol monostearate, sorbitan monolaurate, polyoxyethylene sorbitan monolaurate.

The weight average molecular weight of the nonionic surfactant is preferably in the range of from 300 to 10,000, and particularly preferably in the range of from 500 to 5,000.

As anionic surfactants, higher alcohols (C ₈
To C ₂₂ ) sulfates [eg, sodium salt of lauryl alcohol sulfate, sodium salt of octyl alcohol sulfate, ammonium salt of lauryl alcohol sulfate, “Teepol-81” (trade name, manufactured by Ciel Chemical), secondary sodium alkyl Sulfates], aliphatic alcohol phosphate salts (for example,
Sodium salts of cetyl alcohol phosphate, etc., alkylaryl sulfonates (eg, sodium salt of dodecylbenzenesulfonic acid, sodium salt of isopropylnaphthalenesulfonic acid, sodium salt of dinaphthalenedisulfonate, sodium salt of metanitrobenzenesulfonic acid) ), Sulfonates of alkylamides (eg, C ₁₇ H ₃₃ CON (CH ₃ ) CH ₂ SO ₃ Na, etc.), sulfonates of dibasic fatty acid esters (eg, dioctyl sodium sulfosuccinate, sodium sulfosuccinate) Dihexyl ester). Of these, sulfonates are particularly preferably used.

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

Examples of the amine type include polyoxyethylene alkyl amine, N-alkyl propylene amine, N-alkyl polyethylene polyamine, N-alkyl polyethylene polyamine dimethyl sulfate, alkyl biguanide, long chain amine oxide, alkyl imidazoline, 1-hydroxyethyl- 2-alkylimidazoline, 1-acetylaminoethyl-2-alkylimidazoline, 2-alkyl-
4-methyl-4-hydroxymethyloxazoline and the like.

Examples of the quaternary ammonium salt type include long-chain primary
Amine salt, alkyltrimethylammonium salt, dialkyldimethylethylammonium salt, alkyldimethylammonium salt, alkyldimethylbenzylammonium salt, alkylpyridinium salt, alkylquinolinium salt, alkylisoquinolinium salt, alkylpyridinium sulfate, stearamide methyl Pyridinium salt, acylaminoethyldiethylamine salt, acylaminoethylmethyldiethylammonium salt, alkylamidopropyldimethylbenzylammonium salt, fatty acid polyethylene polyamide, acylaminoethylbiridinium salt, acylcholaminoformylmethylpyridinium salt, stearooxymethylpyridinium Salt, fatty acid triethanolamine, fatty acid triethanolamine formate, trioxyethylene fatty acid triethanolamine Ethanolamine, fatty dibutylaminoethanol, cetyl oxymethyl pyridinium salt,
P-isooctylphenoxyethoxyethyldimethylbenzylammonium salt and the like. ("Alkyl" in the examples of the above compounds refers to straight-chain or partially-substituted alkyl having 6 to 20 carbon atoms. Specifically, straight-chain alkyl such as hexyl, octyl, cetyl, and stearyl is exemplified by "alkyl". Among them, water-soluble quaternary ammonium salt type cationic surfactants are particularly effective, and among them, alkyltrimethylammonium salt, alkyldimethylbenzylammonium salt, ethylene oxide-added ammonium salt and the like are preferable. is there. 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 copolymerization 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.

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

These surfactants can be contained in the range of 0.5 to 10% by weight.

Examples of the inorganic reducing agent include sodium sulfite, potassium sulfite, ammonium sulfite, sodium bisulfite, sulfites such as potassium bisulfite, sodium phosphite, potassium phosphite, sodium hydrogen phosphite,
Phosphates such as potassium hydrogen phosphite, sodium dihydrogen phosphite, and dipotassium hydrogen phosphite, hydrazine, sodium thiosulfate, sodium dithionite, and the like can be given. The agent is a sulfite. These reducing agents are contained in the range of 0.1 to 10% by weight, more preferably 0.5 to 5% by weight.

The developer and its replenisher include other known additives,
For example, a water-soluble or alkali-soluble organic reducing agent, an organic carboxylic acid and a salt thereof can be contained.

Examples of the organic reducing agent include phenol compounds such as hydroquinone, metol and methoxyquinone, and amine compounds such as phenylenediamine and phenylhydrazine.

The organic carboxylic acid includes an aliphatic carboxylic acid having 6 to 20 carbon atoms and an aromatic carboxylic acid having a benzene ring or a naphthalene ring substituted with a carboxyl group.

As the aliphatic carboxylic acid, an alkanoic acid having 6 to 20 carbon atoms is preferable, and specific examples thereof include caproic acid, enantiic acid, caprylic acid, pelargonic acid, capric acid, lauric acid, mystyric acid, palmitic acid, and stearic acid. And particularly preferred are alkanoic acids having 6 to 12 carbon atoms. In addition, fatty acids having a double bond in the carbon chain or branched carbon chains may be used. The 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, o-chlorobenzoic acid, p-chlorobenzoic acid, o-hydroxybenzoic acid, p-hydroxybenzoic acid, p-tert
-Butylbenzoic acid, o-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, 1-hydroxy-2-naphthoic acid, 3-hydroxy-2-naphthoic acid, 2-hydroxy-1-naphthoic acid,
There are 1-naphthoic acid and 2-naphthoic acid.

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

The content of the aliphatic carboxylic acid and the aromatic carboxylic acid is preferably 0.1 to 10% by weight.

Further, the following additives can be added to the developer and the replenisher in the present invention in order to enhance the developing performance. For example, NaCl, KCl, KB described in JP-A-58-75152
neutral salts such as r, EDTA and NTA described in JP-A-59-190952
Chelating agents such as (Co) described in JP-A-59-121336;
(NH ₃ )] ₆ Cl _{3 and} other amphoteric polymer electrolytes such as a copolymer of vinylbenzyltrimethylammonium chloride and sodium acrylate described in JP-A-56-142528, and JP-A-58-59444. Inorganic lithium compounds such as lithium chloride described, organic lithium compounds such as lithium benzoate described in JP-B-50-34442, JP-A-59-7525.
An organic metal surfactant containing Si, Ti, etc. described in JP-A No. 5 (1993) -59, and an organic boron compound described in JP-A-59-84241 are exemplified.

Further, the negative / positive common developer used in the method of the present invention includes JP-A Nos. 62-24263, 62-24264, and 62-2576.
No. 1, 62-35351, 62-75535, 62-89060,
No. 62-125357, No. 62-133460, No. 62-159148, No.
62-168160, 62-175758, 63-200154, 63
And developing solutions as described in JP-A-205658.

PS plates to which the present invention is applied include those in which a layer of the following photosensitive composition is provided on a support having a hydrophilic surface.

1) Photocrosslinkable photosensitive resin composition The photosensitive component in the photocrosslinkable photosensitive resin composition comprises a photosensitive resin having an unsaturated double bond in a molecule. For example, US Pat. No. 3,030,208 describes As described in the specification of 3,435,237 and 3,622,320, etc.,
Examples thereof include a photosensitive resin having —CH ＝ CH—CO— as a photosensitive group in a polymer main chain, and polyvinyl cinnamate having a photosensitive group in a side chain of the polymer.

2) Photopolymerizable photosensitive resin composition A photopolymerizable composition containing an addition-polymerizable unsaturated compound, comprising a monomer having a double bond and a polymer binder, which is a typical example of such a composition. These are described, for example, in U.S. Pat. Nos. 2,760,863 and 2,791,504.

The photopolymerizable photosensitive resin composition includes a photopolymerization initiator (for example, a benzoin derivative such as benzoin methyl ether, a benzophenone derivative such as benzophenone, a thioxanthone derivative, an anthraquinone derivative, and an acridone derivative) which are generally known in this technical field. ) Is added.

3) Photosensitive composition containing diazo compound The diazo compound in the photosensitive composition is, for example, preferably a diazo resin represented by a condensate of an aromatic diazonium salt with formaldehyde or acetaldehyde. Particularly preferably, a salt of a condensate of p-diazodiphenylamine with formaldehyde or acetaldehyde,
For example, hexafluoroborate, tetrafluoroborate, a diazo resin inorganic salt which is a reaction product of a perchlorate or a periodate and the condensate, and US Patent 3,300,30
Examples thereof include an organic salt of a diazo resin, which is a reaction product of the condensate and a sulfonic acid, as described in the specification of JP-A No. 9-1990. Furthermore, diazo resins are preferably used with binders. As such a binder, various polymer compounds can be used, and preferably, Japanese Patent Application Laid-Open No. 54-98
No. 613, a monomer having an aromatic hydroxyl group, for example, N- (4-hydroxyphenyl)
A copolymer of acrylamide, N- (4-hydroxyphenyl) methacrylamide, o-, m-, or p-hydroxystyrene, o-, m-, or p-hydroxyphenyl methacrylate with another monomer; U.S. Patent 4,123,27
Polymer containing a hydroxyethyl acrylate unit or hydroxyethyl methacrylate unit as a main repeating unit, a natural resin such as shellac, rosin, polyvinyl alcohol, and the like described in US Pat. No. 3,751,257 described in US Pat. Polyamide resin as described in U.S. Pat. Cellulose derivatives such as phthalate are included.

4) Photosensitive composition containing o-quinonediazide compound In the photosensitive composition containing o-quinonediazide compound, it is preferable to use the o-quinonediazide compound and an alkali-soluble resin in combination.

Examples of the o-quinonediazide compound include an ester compound of o-naphthoquinonediazidesulfonic acid and a polycondensation resin of phenols and aldehydes or ketones.

Examples of the phenols include phenol, o
-Cresol, m-cresol, p-cresol, 3,5
Monohydric phenols such as xylenol, carvacrol, and thymol; dihydric phenols such as catechol, resorcin and hydroquinone; and trihydric phenols such as pyrogallol and phlorogruncin. Examples of the aldehyde include formaldehyde, benzaldehyde, acetaldehyde, crotonaldehyde, and furfural. Preferred among these are formaldehyde and benzaldehyde. Examples of the ketone include acetone and methyl ethyl ketone.

Specific examples of the polycondensation resin include phenol
Formaldehyde resin, m-cresol-formaldehyde resin, m-, p-mixed cresol-formaldehyde resin, resorcin-benzaldehyde resin, pyrogallol-acetone resin and the like.

The condensation rate of o-naphthoquinonediazidesulfonic acid with respect to the OH groups of phenols of the o-naphthoquinonediazide compound (reaction rate per OH group) is preferably 15 to 80%, more preferably 20 to 45%.

As the o-quinonediazide compound, JP-A-58-43451
The following compounds described in Japanese Patent Application Laid-Open Publication No. H10-260 can also be used.

Also, Japanese Patent Publication Nos. 37-1953, 37-3627 and 37-13109
Nos. 40-26126, 40-3801, 45-5604, 4
Nos. 5-27345, 51-13013, JP-A-48-96575, 48
And 1,2-quinonediazide compounds described in JP-A-63802 and JP-A-48-63803.

Examples of the support used for the PS plate include paper, plastic (eg, polyethylene, polypropylene, and polystyrene) laminated paper, metal plates such as aluminum (including aluminum alloys), zinc, and copper; and cellulose diacetate. , Cellulose triacetate, cellulose propionate, polyethylene terephthalate, polyethylene, polypropylene, polycarbonate, plastic films such as polyvinyl acetal, etc. Of these, aluminum and a composite support coated with aluminum are particularly preferred.

The surface of the aluminum material is desirably subjected to a surface roughening treatment for the purpose of increasing water retention and improving adhesion to the photosensitive layer.

Examples of the surface roughening method include generally known brush polishing methods, pole polishing methods, electrolytic etching, chemical etching, liquid honing, sand blasting, and the like, and combinations thereof. Preferably, brush polishing, electrolytic etching, and chemical polishing are used. Etching and liquid honing,
Of these, a surface roughening method including the use of electrolytic etching is particularly preferred. As the electrolytic bath used in the electrolytic etching, an aqueous solution containing an acid, an alkali or a salt thereof or an aqueous solution containing an organic solvent is used, and among these, an electrolytic solution containing hydrochloric acid, nitric acid or a salt thereof is used. Liquids are preferred. Further, the aluminum plate subjected to the surface roughening treatment is desmutted with an acid or alkali aqueous solution as required.

The aluminum plate thus obtained is desirably subjected to anodic oxidation treatment, and particularly preferably a method of treating the aluminum plate in a bath containing sulfuric acid or phosphoric acid. Further, if necessary, a surface treatment such as a sealing treatment or other immersion in an aqueous solution of potassium fluorozirconate can be performed.

In the method of the present invention, the developer and the development replenisher are preferably selected from (A) alkali silicate, (B) surfactant, (C) organic solvent, and (D) reducing inorganic salt as described above. In the developer, the preferred ranges of the concentrations (A) to (D) are (A) 0.3 to 10% by weight, (B) 0.0110% by weight,
(C) is 0.1 to 10% by weight, (D) is 0.1 to 20% by weight, and the preferred concentration range in the developing replenisher is (A) 0.5 to 0.5% by weight.
-10% by weight, (B) 0.05-15% by weight, (C) 0.1-1%
0% by weight and (D) 0.5 to 30% by weight.

In the method of the present invention, it is preferable to make the concentrations of the above components different between the developer and the developer replenisher. Specifically, there is an embodiment in which the concentration of the surfactant and / or the reducing inorganic salt is larger in the developing replenisher than in the developing solution.

In the method of the present invention, the pH of the developer replenisher is preferably higher than the pH of the developer. The pH of the developer is preferably 12.5
And the pH of the developing replenisher is preferably 12.8 to 13.8.
It is.

In the present invention, one kind of development replenisher is used. However, the present invention also includes a form in which a concentrated solution is used as the development replenisher and diluted with dilution water.

In the present invention, as a means for detecting a decrease in the activity of the developer, various conventionally known methods, for example, a method for measuring the fatigue of the developer, a method for measuring the throughput of the PS plate, and the like can be applied. .

To measure the degree of fatigue of the developer, the pH of the developer
, The method of measuring the elution degree of the PS plate electrically or optically, the method of measuring the developer temperature, the outside air temperature or the shower flow rate and integrating over time, and the like. , A method of measuring the plate area of the PS plate to be processed, a method of measuring the non-image area of the plate after development,
A method of measuring the non-image area of the PS plate that is processed using the integrated value of the image scanning signal by the scanner or the integrated value of the modulation input signal of the laser beam used for exposure, and processing by reading the visible image after exposure To measure the non-image area of the PS plate. It is also possible to use some of the above methods in combination.

Among the above-mentioned various methods, a preferable one is PS
A method for measuring the number of plates, the length in the transport direction, or the area; a method for measuring the elution degree of the photosensitive layer of the PS plate in the developing step by impedance; and a method for measuring the conductivity or pH of the developer.

Examples of preferable combinations of the plate type and the detection means include the following (1) to (3).

(1) Plate area for negative PS plate and conductivity of developer for positive PS plate.

(2) Plate area for negative PS plate and plate surface impedance during development process for positive PS plate.

(3) The length of the PS plate in the transport direction compared to the negative PS plate, positive type
The conductivity of the developer relative to the PS plate.

In the present invention, the plate type is detected by different means, and the replenishment amount corresponding to each is performed. The replenishment amount corresponding to the plate type and the detection means can be easily obtained in advance by an experiment, Will be described later.

In the present invention, the development replenishment is preferably replenished separately for processing fatigue and aging fatigue, and replenishment for processing fatigue is preferably performed according to the present invention.

In the present invention, the detection of the plate type and the switching of the control method based on the detection result may be performed manually or automatically.

Next, the processing apparatus of the present invention will be described with reference to the drawings.

FIG. 1 is a configuration diagram of a processing apparatus according to the present invention. In the figure, 1 is a conveying roller, 2 is a squeezing roller, 3 is a skewer roller, 4 is a receiving roller, 5 is a brush roller, 6 is a developer tank, 7 is a pump, 8 is a shower pipe, and 9 is a developer replenisher tank. , P are PS plate transport paths.

Reference numeral 10 denotes a glass cell for measuring conductivity, which measures the conductivity of the developer in the developing tank 6. A signal sent from the cell controls a replenishing device 12 by a conductivity meter main body (not shown) and a control device 11 connected thereto.

Reference numeral 13 denotes an optical sensor.Optical sensors are arranged at positions close to the corners and the center of one side of the insertion area of the smallest standard size PS plate, and optical sensors are respectively arranged in the gradually increasing size PS plate insertion area. A sensor is arranged so that a PS plate size can be detected based on PS plate detection signals from two optical sensors. Alternatively, the length of the PS plate in the transport direction may be detected based on the passage time under the optical sensor 13 by detecting the presence of the PS plate. Further, the leading end of the PS plate may be detected by an optical sensor or the like to detect the number of PS plates.

The relationship between the detection result regarding the decrease in developer activity and the replenishment amount is based on the amount of decrease in conductivity when processing a large number of positive PS plates using the new solution and fatigued to the permissible limit of sensitivity fluctuation. (C) and the replenishment amount (appropriate replenishment amount) (p ₁ ) required to return the sensitivity of the solution to the sensitivity of the new solution at this time are experimentally obtained. Separately, an appropriate replenishment amount (p ₂ ) with respect to the area (a) of the PS plate processed and processed in a similar manner by using a negative PS plate in multiple sheets is experimentally obtained.

The relationship between the detection result and the replenishment amount can be similarly obtained for other measured amounts.

Further, the developing method and apparatus of the present invention can be provided with a washing step, a rinsing step, a gum processing step, a drying step, and the like as necessary as the post-development processing step.

〔Example〕

 Hereinafter, the present invention will be described more specifically with reference to examples.

Example 1 Esterified product of naphthoquinone 1,2-diazido-5-sulfonyl chloride and resorcin-benzaldehyde resin (described in Example 1 of JP-A-56-1044)
A photosensitive solution was prepared by dissolving 9 parts by weight of cresol novolak resin and 0.12 part by weight of Victoria Pure Blue BOH (manufactured by Hodogaya Chemical Co., Ltd., dye) in 100 parts by weight of methylcellsorb. Aluminum plate was grained with a thickness of 0.3mm was anodized in sulfuric acid, making the oxide film of 2.7 g / m ^2, and dried thoroughly washed, the photosensitive solution was coated and dried thereon, about 2.4g A PS plate having a / m ² photosensitive layer was obtained. The positive PS plate obtained in this way is 1003 mm x
A large number of pieces cut to a size of 800 ml were prepared, and these were exposed through a transparent positive for 60 seconds from a distance of 80 cm using a 2 kW metal halide lamp.

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

Aluminum plate was grained with a thickness of 0.24mm was anodized in sulfuric acid, making the oxide film of about 1.5 g / m ^2, washed well, and immersed in an aqueous sodium silicate solution, after sufficiently washing with water,
After drying, a photosensitive solution having the following composition was applied.

Copolymer of p-hydroxyphenyl methacrylamide, acrylonitrile, ethyl acrylate, and methacrylic acid (molar ratio: 8.5: 24: 60.5: 7 in the order given above) 5.0 parts by weight Hexacondensate of p-diazodiphenylamine and valaformaldehyde Fluorophosphate 0.5 part by weight Victoria Pure Blue BOH (manufactured by Hodogaya Chemical Industry Co., Ltd.) 0.1 part by weight Ethylene glycol monomethyl ether 100 parts by weight The coating amount after drying was 1.8 g / m ² .

The negative PS plate obtained in this way is 800 mm × 1003 mm
A large number of pieces cut to the size were prepared and exposed to a transparent negative through a metal halide lamp of 2 kW from a distance of 80 cm for 50 seconds.

 Next, a concentrated developing solution having the following composition was prepared.

Benzyl alcohol 75.0 g 2-Naphthoic acid 150.0 g Benzoic acid 300.0 g 50% aqueous solution of potassium hydroxide 770.0 g Emulgen 147 (Kao Corporation, nonionic surfactant) 8.0 g Potassium silicate aqueous solution 540.0 g (SiO ₂ content 26% by weight) , K ₂ O-containing 13% by weight) 40% aqueous solution of potassium sulfite 450.0 g water 1300.0 g A developing solution obtained by mixing the above-mentioned developing concentrated solution and water at a ratio of 1: 7 in the developing solution tank 6 of the automatic developing machine shown in FIG. 24 and the temperature of the developer was adjusted to 27 ° C. Further, a developing replenisher having the following composition was charged into the developing replenisher tank 9.

Benzyl alcohol 60.0 g 2-Naphthoic acid 120.0 g Benzoic acid 300.0 g 50% potassium hydroxide aqueous solution 1400.0 g Emulgen 147 80.0 g (Kao Corporation, nonionic surfactant) Potassium silicate aqueous solution 1200.0 g (SiO ₂ content 26% by weight , K ₂ O-containing 13% by weight) 40% aqueous solution of potassium sulfite 400.0 g water 2300.0 g Next, the exposed PS plate was treated using an automatic developing machine shown in FIG.

A negative / positive switch (not shown) is provided on the insertion table of the automatic processor, and the optical sensor 13 is used when processing a negative PS plate.
The area of the PS plate is detected and replenished according to the area (40 mltr /
m ² ), during the processing of the positive PS plate, the conductivity after development was detected, and when 3 mS from the new solution, the development replenisher of 1200 mltr was replenished. CG-20 as glass cell 10 for conductivity measurement
1PL (manufactured by Toa Denpa) was used, and the conductivity meter body used was CM-30ET manufactured by Toa Denpa. During the operation of the processor, 200 mltr of the replenisher was replenished every hour irrespective of the processing of the PS plate, and when the operation was stopped, the replenisher of 50 mltr was replenished per hour. The developed PS plate was washed with water, hand-coated with a commercially available gum, and dried.

With this setting, the exposed positive PS plate can be used in one day.
When the 60 plates and the negative PS plates were processed into 40 plates and processed in a total of 1200 plates in 12 days, a lithographic printing plate having almost the same sensitivity as that obtained by processing with a newly prepared developer was obtained.

Example 2 For the positive PS plate, see Example 2 of JP-A-61-162049.
Impedance is detected by the mechanism of the automatic developing machine (Fig. 2 of JP-A-61-162049) used in the above, and when the load drops by 2.5Ω from the new solution, 200 mltr of the developing replenisher is replenished. When the positive PS plate was processed to 70 plates and the negative PS plate was processed to 30 plates, and a total of 1,000 plates were processed in 10 days, all showed almost the same sensitivity as those processed with the newly prepared developer. A lithographic printing plate having stable dot reproducibility was obtained.

〔The invention's effect〕

According to the present invention, the development finish when the negative PS plate and the positive PS plate are commonly developed with the common developer of the negative PS plate and the positive PS plate which is repeatedly used by replenishing the replenisher is used. Stability is improved. In addition, using one kind of development replenisher,
By simply changing the replenishment amount, negative-positive common development can be stably performed over a long period of time, and thereby the cost of the processing apparatus can be reduced.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an example of a processing apparatus according to the present invention. 6 ... Development tank 9 ... Development replenisher tank 10 ... Glass cell for conductivity measurement 11 ... Control device 12 ... Replenishment device 13 ... Optical sensor

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-62-55658 (JP, A) JP-A-63-100460 (JP, A) JP-A-62-73271 (JP, A) (58) Field (Int. Cl. ⁶ , DB name) G03F 7/00, 7/30

Claims (2)

(57) [Claims] 1. A method for processing a negative photosensitive lithographic printing plate and a positive photosensitive lithographic printing plate in one development zone using one kind of a common negative / positive developer which is repeatedly used, Photosensitive lithographic printing wherein the activity of a developer, which is reduced by processing fatigue, is detected using different detection means depending on the type of plate, and compensated by adding one type of development replenisher in an amount corresponding to each type. Plate processing method. 2. A means for processing in one developing zone using one kind of developing solution, and different detecting means corresponding to plate types of a negative photosensitive lithographic printing plate and a positive photosensitive lithographic printing plate, respectively. A processing apparatus having a function of detecting processing fatigue by using the same and replenishing one type of replenisher in an amount corresponding to each.