JPH0296773A - Method for processing original plate for electrophotographic planographic printing plate - Google Patents

Abstract

PURPOSE:To make it possible to perform the suitable replenishing of a processing solution by detecting the deterioration of the processing solution used for removing the nonimage part of the subject plate by measuring the conductivity or the impedance of the processing solution. CONSTITUTION:The impedance of the processing solution is measured, and the compensated impedance of the processing solution is obtained by substituting the impedance measured and the substitution ratio of a replenisher into an operation expression previously obtained. The replenishing of the replenisher is performed, in the case that the compensated impedance reaches to a prescribed value. The operation expression is obtained experimentally. Thus, a lot of sheets of the original plates is stably processed for a long period, without deteriorating the processing solution and changing the composition of the processing solution.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a non-image area of a lithographic printing plate precursor having a toner image formed by an electrophotographic process on a photoconductor layer provided on a conductive substrate. The present invention relates to a processing method for removing lithographic printing plates. In particular, in the case of processing a large number of original plates, the activity of the processing liquid during the processing is kept constant by automatically replenishing the replenishing liquid, and the non-image area of the photoconductor layer is removed. It relates to a processing method that always performs perfectly.

[Conventional technology]

Today, as lithographic offset printing plates, PS plates that use positive-working photosensitizers whose main components are diazo compounds and phenolic resins, and negative-working photosensitizers whose main components are acrylic monomers and prepolymers are in practical use. However, all of these have low sensitivity, so plate making is performed by contact exposure of a silver halide photographic film master plate on which an image has been recorded in advance. on the other hand,
In recent years, advances in computer image processing, large-capacity data storage, and data communication technology have meant that everything from inputting, correcting, editing, and layout to page layout has become computer-operated, and high-speed communication networks and satellite communications have enabled instant access to remote locations. Electronic can collection systems that can output to terminal blocks have been put into practical use. The demand for electronic editing systems is particularly high in the newspaper printing field, where immediacy is required, and in fields where originals are stored in the form of original film, and printed versions are reproduced as needed based on this. With the development of ultra-high capacity recording media such as optical discs, it is thought that originals will be stored as digital data on these recording media.

However, direct printing plates that create printing plates directly from the output of terminal plotters have hardly been put into practical use.
Even in places where electronic editing systems are in operation, the current situation is that output is performed on silver halide photographic film, and based on this, printing plates are indirectly created by contact exposure to PS plates. This is the light source of the output plotter (e.g. He-N
This is because it is difficult to develop a direct printing plate with a sensitivity high enough to make a printing plate within a practical time using e-lasers, semiconductor lasers, etc.).

Electrophotographic photoreceptors are considered as photoreceptors with high photosensitivity that can provide direct printing plates.

Conventionally, printing plate materials (printing original plates) using electrophotography include, for example, Japanese Patent Publication No. 47-47610 and Japanese Patent Publication No. 48
-40002, Special Publication No. 18325, Special Publication No. 18325, Special Publication No. 18325
Zinc oxide-resin dispersion offset printing plate materials described in Japanese Patent Publication No. 1-15766, Japanese Patent Publication No. 5125761, etc. are known, and after forming a toner image by electrophotography, the non-image area is made insensitive to oil. for use after wetting with a desensitizing solution (for example, a ferrocyanate or an acidic aqueous solution with a ferricyanate). Offset printing plates treated in this way have a stiffness resistance of about 5,000 to 10,000 sheets, and cannot be used for printing beyond this, and if the composition is made suitable for desensitization, the electrostatic properties will deteriorate. , and has disadvantages such as deterioration of image quality. It also has the disadvantage of using harmful cyanide compounds as desensitizing solutions.

Special Publication No. 37-17162, Special Publication No. 38-7758,
Organic photoconductor resin printing plate materials described in Japanese Patent Publication No. 46-39405, Publication No. 52-2437, etc.
For example, an electrophotographic photoreceptor is used in which a photoconductive insulating layer made of an oxazole or oxadiazole compound fixed with a styrene-maleic anhydride copolymer is provided on a grained aluminum plate. After forming a toner image by electrophotography, a printing plate is formed by dissolving and removing the non-image area with an alkaline organic solvent.

Furthermore, in the above method, a method has been proposed in which an alkaline aqueous solution containing an organic solvent is used as the processing liquid for removing the non-image area.

To process an electrophotographic photoreceptor (lithographic printing plate precursor) having the above-mentioned toner image on the photoconductor layer, apply a treatment solution by spraying or dipping the original in the treatment solution. The photoconductor layer is applied to the surface of the photoconductor layer, and the surface is rubbed with a brush roll or the like to remove the photoconductor layer in non-image areas.

[Problem to be solved by the invention]

When performing such processing on a large number of electrophotographic photoreceptors using the same processing machine, the processing solution deteriorates as processing progresses, and if removal is insufficient, it will adversely affect the image quality of printed matter. The fluid needs to be replenished or replaced. It is troublesome to replenish the processing solution after checking the degree of deterioration of the processing solution, and replenishing the processing solution after it has deteriorated may result in printing plates that are partially inferior. Become.

For this reason, it is desirable to automatically replenish the processing liquid (replenisher) depending on the processing amount of electrophotographic photoreceptors (for example, the number and length of photoreceptors entering the processing machine) and processing time. It is conceivable to replenish the replenisher, but since the area of the toner image formed on this type of photoconductor differs depending on each photoconductor, and therefore the area of the non-image area to be removed differs, The degree of deterioration of the liquid varies, and in the end, proper replenishment is not performed.

[Means to solve the problem]

The present invention processes a large number of electrophotographic photoreceptors having toner images formed on the photoconductor layer by an electrophotographic process while automatically replenishing the processing solution with an appropriate replenisher depending on the deterioration caused by each process. However, it is an object of the present invention to provide a processing method that can stably and completely remove non-image areas.

The present inventors discovered that the conductivity or impedance of a processing solution such as an alkaline aqueous solution changes depending on the amount of the non-image area of the photoconductor layer eluted by the above-mentioned processing, and the present applicant first The proposed automatic developing device for photosensitive lithographic printing plates (PS plates) was developed using a developing replenisher replenishment method (Patent Application No. 178457/1983).
No. 63-4560 and Japanese Patent Application No. 63-4560) can be applied to the removal of the non-image area of the electrophotographic photoreceptor, the above object can be achieved and the present invention has been achieved.

That is, the present invention provides a processing method for removing non-image areas of a large number of lithographic printing plate precursors, the image areas of which are formed from toner images formed by an electrophotographic process on a photoconductor layer provided on a conductive substrate. , the deterioration of the processing solution for removing non-image areas is detected by measuring the conductivity or impedance of the processing solution, and the replenishment solution is automatically processed according to pre-programmed instructions and/or correction calculation formulas. This is a method for processing an original plate for an electrophotographic lithographic printing plate, which is characterized by adding it to a solution to compensate for the deterioration.

In the present invention, the stability of the processing solution can be further improved by adding water corresponding to the amount of water evaporated from the processing solution over time, either continuously or intermittently, in addition to adding the above-mentioned replenisher.

The present invention will be explained in more detail below.

Conductive substrates used in electrophotographic photoreceptors include plastic sheets with conductive surfaces or papers made particularly solvent-impermeable and conductive, aluminum plates, zinc plates,
Or has a hydrophilic surface such as a bimetallic plate such as a copper-aluminum plate, a copper-stainless steel plate, a chrome-copper plate, or a tri-metallic plate such as a chromium-copper-aluminum plate, a chrome-lead-iron plate, a chromium-copper-stainless steel plate, etc. A conductive substrate is used, and its thickness is preferably 0.1 to 3 mm, particularly preferably 0.1 to 0.5 mm. Among these substrates, aluminum plates are preferably used. The aluminum plate used in the present invention is a plate-shaped body such as pure aluminum whose main component is aluminum or an aluminum alloy containing a small amount of foreign atoms, and its composition is not specified, and publicly known and publicly used materials are used as appropriate. You can.

This aluminum plate can be used after being grained and anodized using a known method. Prior to the graining treatment, in order to remove rolling fat from the surface of the aluminum plate, degreasing treatment with a surfactant or an alkaline aqueous solution is performed, if desired, and then the graining treatment is performed. Graining treatment methods include a method of mechanically roughening the surface, a method of electrochemically dissolving the surface, and a method of selectively dissolving the surface chemically. As a method for mechanically roughening the surface, known methods such as ball polishing, brush polishing, blast polishing, buff polishing, etc. can be used. Further, as an electrochemical surface roughening method, there is a method in which alternating current or direct current is used in a hydrochloric acid or nitric acid electrolyte. Furthermore, a method combining both methods can also be used, as disclosed in Japanese Patent Application Laid-Open No. 54-63,902.

The aluminum plate thus roughened is subjected to alkali etching treatment and neutralization treatment as required.

The aluminum plate thus treated is anodized. As the electrolyte used in the anodizing treatment, sulfuric acid, phosphoric acid, oxalic acid, chromic acid, or a mixed acid thereof is used, and the electrolyte and its concentration are determined as appropriate depending on the type of electrolyte. Since the treatment conditions for anodizing vary depending on the electrolyte used, it cannot be generally specified, but numerically, the electrolyte concentration is 1 to 80% by weight solution, and the solution temperature is 5 to 70% by weight.
°C1 current density 5~60A/dpo, voltage 1~100■,
It is preferable that the electrolysis time is in the range of 10 seconds to 50 minutes. The amount of anodic oxide film is 0. The range is preferably 1 to 1.0 g/rrf, more preferably 1 to 6 g/nr.

A known electrophotographic photosensitive layer (photoconductive layer) is provided on the conductive substrate thus obtained to obtain an electrophotographic photoreceptor.

As the photoconductive material used in the photoconductive layer, many conventionally known organic or inorganic compounds can be used. For example, known dispersible photoconductive materials include inorganic photoconductive materials fZ1 such as selenium, selenium-tellurium, cadmium sulfide, and zinc oxide. In addition, as organic photoconductive compounds, I) triazole derivatives described in U.S. Patent No. 3,112,197 etc., 2) U.S. Patent Section 3,1
3) Imidazole derivatives described in Japanese Patent Publication No. 37-16,096, etc., 4) U.S. Patent No. 3,615,402, 3,820.
No. 989, No. 3,542,544, Special Publication No. 45-55
No. 5, No. 51-10,983, JP-A No. 51-93, 2
No. 24, No. 55-108, 667, No. 55-1569
53, U.S. Patent No. 56-36゜656 specification, publications, etc.;
．． No. 746, JP-A-55-88,064, JP-A No. 55-8
No. 8,065, No. 49-105,537, No. 55-5
No. 1,086, No. 56-80゜051, No. 56-88
, No. 141, No. 57-45.545, No. 54-112
, 637, 55-74,546, publications, etc., 6) U.S. Patent Section 3,615,404, Japanese Patent Publication No. 51
-10.105, 46-3,712, 47-2
No. 8,336, JP-A-54-83,435, JP-A No. 54-
No. 110,836, specification No. 54-119.925,
Phenyldiamine derivatives described in publications, etc. 7) U.S. Patent Section 3.5 (i7,450, 3,180)
．． No. 703, No. 3,240,597, No. 3゜6513
．． No. 520-, No. 4,232,103, No. 4.175
, No. 961, No. 4,012,376, West German patent (D
AS) No. 1,110.518, Special Publication No. 1970-35, 70
No. 2, No. 39-27,577, JP-A-55-144,
No. 250, No. 56119.132, No. 56-22,4
8) Amino-substituted chalcone derivatives described in U.S. Patent No. 3,526,501; 9) Arylamine derivatives described in U.S. Patent No. 3,526,501; and 9) Arylamine derivatives described in U.S. Patent No. 3,542,546. N,N-bicarbacil derivatives described in 10) U.S. Patent Section 3,
11) Styryl anthracene derivatives described in JP-A-56-46-234, etc.; 12) Oxazole derivatives described in JP-A-54-110,837, etc. 13) U.S. Pat. No. 3,717,462, JP-A-1973
No. 59,143 (corresponding to U.S. Pat. No. 1.1.50987), No. 55-52.063, No. 55-52,06
No. 4, No. 55-46.760, No. 55-85,495
No. 57-11,350, No. 57-148,749
14) U.S. Pat. No. 4,047,948, U.S. Pat. No. 4,047,047
．． No. 949, No. 4,265,990, No. 4.273,
No. 846, No. 4,299,897, No. 4,306,0
Benzidine derivatives described in 08 specification etc., 15) JP-A-58-190,953, JP-A-59-95.
No. 540, No. 59-97, 148, No. 59-195,
Examples include stilbene derivatives described in Japanese Patent No. 658 and Japanese Patent No. 62-36,674.

Further, in addition to the above-mentioned low-molecular photoconductive compounds, the following high-molecular compounds can also be used.

16) Polyvinylcarbazole and its derivatives described in Japanese Patent Publication No. 10,966, 1972, 17) Japanese Patent Publication No. 1987-1
Polyvinylpyrene, polyvinylanthracene, poly-2-vinyl-4(4'-dimethylaminophenyl)-5-phenyloxazole, poly-3-vinyl-N- described in No. 8,674 and No. 43-19.192 Vinyl polymers such as ethylcarbazole, 18) Polymers such as polyacenaphthylene, polyindene, and copolymers of acenaphthylene and styrene described in Japanese Patent Publication No. 1986-193, 19) Japanese Patent Publication No. 13940-1982 Condensation resins such as pyrene-formaldehyde resin, fromopyrene-formaldehyde resin, and ethyl rubber formaldehyde resin as described in publications, etc.; 20) as described in JP-A-56-90,883 and JP-A-56-E-61.550; In addition, various pigments, dyes, etc. can be used for purposes such as improving the sensitivity of the photoconductor and giving it a desired photosensitive wavelength range. Examples of these include: 1) U.S. Patent No. 4,436,800;
No. 506, JP-A-47-37543, JP-A No. 5B-123
, No. 541, No. 5B-192,042, No. 58-21
9.263, 59-78゜356, 60i79
, No. 14G, No. 61-148.453, No. 61. -2
No. 38,063, Special Publication No. 60-5941, No. 60-4
Monoazo, bisazo, and trisazo pigments described in U.S. Patent Nos. 3,397,086 and 4.666.
Phthalocyanine pigments such as metal phthalocyanine or metal-free phthalocyanine described in US Pat. No. 802, etc. 3) Perylene-based Dn materials described in US Pat. Indigo, thioindigo derivatives 5) British Patent No. 2. Quinacridone pigments described in No. 237.679 etc. 6) British Patent No. 2,237,678, Japanese Unexamined Patent Publication No. 51-1
84,348, 62-28.738, etc. 7) Bisbenzimidazole pigments described in JP-A-47-30,331, etc. 8) U.S. Patent No. 4,396, No. 610, 4,644.
9) The azulenium salt pigment described in JP-A No. 59-53,850, JP-A No. 61-212.542, etc. Also, as a sensitizing agent,
“Sensitizer” 125 Shin (Kodansha 81987), “Electronic Photography” 1, 2, 9 (1973) r Organic Synthetic Chemistry” I Sat Nα1
121010 (1966) and the like can be used. For example, 10) U.S. Patent No. 3,141,770, 4°283
．． No. 475, Special Publication No. 48-25,658, Japanese Patent Publication No. 6
Byrylium dye described in No. 2-71,965 etc. 11) Applied 0ptics 5uppl
ea+ent 3,50 (1969), JP-A-1983-
12) Cyanine dyes described in U.S. Pat.
．． No. 588, No. 60-252.5], No. 7, etc. These organic photoconductive materials may be used alone or in combination of two or more.

For the purpose of improving sensitivity, the photoconductive layer of the present invention may contain electron-withdrawing compounds such as trinitrofluorenone, chloranil, tetracyanoethylene, etc.
, No. 439, No. 5B-102, 239, No. 513-1
．． Examples include compounds described in No. 29,439 and No. 62-71,965.

In a photoreceptor for electrophotographic engraving, the photoconductive compound itself may have film properties, but if the photoconductive compound does not have film properties, a binding resin can be used. As the binding resin, resins known in the field of electrophotography can be used. In order to create a printing plate using a photoreceptor for electrophotographic engraving, it is necessary to finally remove the photoconductive layer in the non-image area, but this process is difficult due to the solubility of the photoconductive layer in the etching solution or the It is impossible to make general statements because it depends on the relative relationship between the image and the etching solution, such as its resistivity. The binding resin is preferably a polymer compound that is soluble or dispersible in the etching solution described below.

Specifically, for example, a copolymer of styrene and maleic anhydride, a copolymer of styrene and monoalkyl maleic anhydride, a methacrylic acid/methacrylic ester copolymer, a styrene/methacrylic acid/methacrylic ester copolymer combination, acrylic acid methacrylic ester copolymer,
Acrylic esters such as styrene/acrylic acid/methacrylic ester copolymers, vinyl acetate/crotonic acid ester copolymers, vinyl acetate/crotonic acid/methacrylic ester copolymers, methacrylic esters, styrene, vinyl acetate, etc. Acids, copolymers with carboxylic acid-containing monomers such as methacrylic acid, itaconic acid, crotonic acid, maleic acid, maleic anhydride, fumaric acid, or monomers containing acid anhydride groups, methacrylic acid amide, vinylpyrrolidone, phenolic Examples include copolymers containing monomers having hydroxyl groups, sulfonic acid groups, sulfonamide groups, and sulfonimide groups, phenol resins, partially saponified vinyl acetate resins, xylene resins, and vinyl acetal resins such as polyvinyl butyral. . A copolymer containing a heptamer having an acid anhydride group or a carboxylic acid group as a copolymerization component, and a phenol resin have a high charge retention ability of the photoconductive layer when used as a photoreceptor for electrophotographic engraving. It can be used with good results.

As the copolymer containing a monomer having an acid anhydride group as a copolymerization component, a copolymer of styrene and maleic anhydride is preferable. Half esters of this copolymer can also be used.

Copolymers containing a heptamer having a carboxylic acid group as a copolymerization component include two or more copolymers of acrylic acid or methacrylic acid and an alkyl ester, aryl ester, or aralkyl ester of acrylic acid or methacrylic acid. Combination is preferred. Further, preferable examples include a copolymer of vinyl acetate and crotonic acid, and a terpolymer of vinyl acetate, a vinyl ester of a carboxylic acid having 2 to 18 carbon atoms, and crotonic acid. Among the phenolic resins, phenol, 0-cresol, m-
Examples include novolanc resins obtained by condensing cresol or p~cresol with formaldehyde or acetaldehyde under acidic conditions. The binding resin may be used alone or in combination of two or more.

When using a photoconductive compound and a binding resin, the sensitivity decreases if the content of the photoconductive compound is small, so the amount of the photoconductive compound should be 0.05 part by weight or more per 1 part by weight of the binding resin. Preferably, it can be used in an amount of 0.1 part by weight or more. In addition, if the photoconductive layer is too thin, it will not be able to charge the charge necessary for development, and if it is too thick, etching will occur in the plane direction called side etching, making it impossible to obtain a good image. 0.1-30μ, more preferably 0. Can be used at 5-10μ.

The electrophotographic printing plate of the present invention can be obtained by coating a photoconductive layer on a conductive substrate according to a conventional method. When creating a photoconductive layer, the components constituting the photoconductive layer can be contained in the same layer, or they can be contained separately in two or more layers, for example, by using different charge carrier generating substances and charge carrier transporting substances. There are known methods for separating the layer into layers, and it can be produced by any of these methods. The coating solution is prepared by dissolving each component constituting the photoconductive layer in an appropriate solvent, but when using components that are insoluble in solvents such as pigments, use a dispersion machine such as a ball mill, paint shaker, dyno mill, or attritor. It is used after being dispersed to a particle size of 5 μm to 0.1 μm. The binding resin and other additives used in the photoconductive layer can be added during or after dispersing the pigment. The coating liquid prepared in this way can be applied by spin coating, blade coating, knife coating, reverse roll coating,
A printing plate for electrophotolithography can be obtained by coating and drying on a substrate by a known method such as dip coating, rod bar coating, or spray coating. As a solvent for creating a coating solution,
Halogenated hydrocarbons such as dichloromethane, dichloroethane, and chloroform, alcohols such as methanol and ethanol, ketones such as acetone, methyl ethyl ketone, and cyclohexanone, glycol ethers such as ethylene glycol monomethyl ether and 2-methoxyethyl acetate, tetrahydrofuran, and dioxane. and esters such as ethyl acetate and butyl acetate.

In addition to the photoconductive compound and the binding resin, the photoconductive layer may contain plasticizers, surfactants, and other additives as necessary to improve the film properties such as flexibility and coating surface condition of the photoconductive layer. agent can be added. Examples of the plasticizer include biphenyl, chlorinated biphenyl, 0-terphenyl, p-terphenyl, dibutyl phthalate, dimethyl glycol phthalate, dioctyl phthalate, triphenyl phosphoric acid, and the like.

The electrophotographic printing plate used in the present invention can be produced by a known process using the above-mentioned electrophotographic photoreceptor. That is, it is charged substantially uniformly in a dark place, and an electrostatic latent image is formed by imagewise exposure. As for the exposure method,
Examples include scanning exposure using a semiconductor laser, He--Ne laser, etc., reflection image exposure using a xenon lamp, tungsten lamp, fluorescent lamp, etc. as a light source, and contact exposure using a transparent positive film. Next, the electrostatic latent image is developed with toner. As the developing method, various conventionally known methods such as cascade development, magnetic brush development, powder cloud development, and liquid development can be used. Among these, liquid development is capable of forming fine images and is suitable for creating printing plates. The formed toner image can be fixed by a known fixing method, such as heat fixing, pressure fixing, solvent fixing, or the like.

A printing plate can be prepared by allowing the toner image thus formed to act as a resist and removing the photoconductive layer in non-image areas using a processing liquid.

As the processing liquid for removing the photoconductive insulating layer in the non-image area after toner image formation, any solvent can be used as long as it can remove the photoconductive insulating layer and has conductivity, preferably a solvent with conductivity. An alkaline solvent is used. The conductive alkaline solvent mentioned here is an aqueous solution containing an alkaline compound or a mixture of an aqueous solution containing an alkaline compound and an organic solvent. Alkaline compounds include sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, potassium silicate, sodium metasilicate, potassium metasilicate, sodium phosphate, potassium phosphate, ammonia, and monoethanolamine and jetanolamine. , amino alcohols such as triethanolamine, and any organic and inorganic alkaline compounds.

As described above, water or a mixture of many organic solvents and water can be used as the solvent for the treatment liquid, but from the viewpoint of odor and pollution, a treatment liquid mainly composed of water is preferably used. If necessary, various organic solvents can be added to the treatment liquid mainly composed of water. Preferred organic solvents include methanol, ethanol, propatool,
Lower alcohols such as butanol, benzyl alcohol, phenethyl alcohol, aromatic alcohols, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, cellosolves, and amino alcohols such as monoethanolamine, jetanolamine, triethanolamine, etc. I can list them. Further, the etching solution used contains a surfactant, an antifoaming agent, and various other additives as necessary.

It is preferable that the toner forming the image area contains a resin component having resistivity to the processing liquid. Examples of resin components include acrylic resins using methacrylic acid, methacrylic acid esters, etc., vinyl acetate resins, copolymers of vinyl acetate and ethylene or vinyl chloride, vinyl chloride resins, vinylidene chloride resins, and vinyls such as polyvinyl butyral. Acetal resin, polystyrene, copolymers of styrene and butadiene, methacrylic esters, etc., polyethylene, polypropylene and its chlorinated products, polyester resins (e.g., polyethylene terephthalate, polyethylene isophthalate, polycarbonate of bisphenol A, polyamide resins (e.g., polycabramide) , poly, xamethylene aziboamide, polyhexamethylene sebamide), phenolic resin, xylene resin, alkyd resin, vinyl modified alkyd resin, gelatin,
Examples include cellulose ester derivatives such as carboxymethylcellulose, waxes, polyolefins, and waxes.

In the electrophotographic photoreceptor used in the present invention, if necessary, casein, polyvinyl alcohol, ethyl cellulose, phenol resin, styrene-maleic anhydride copolymer, polyacrylic acid, Monoaminomonocarboxylic acids such as monoethanolamine, jetanolamine, trimethanolamine, tripropaturamine, triethanolamine and their hydrochlorides, oxalates, phosphates, aminoacetic acid, alanine; for example, saison, threonine, dihydroxy Oxyamino acids such as ethylglycine; Sulfur-containing amino acids such as cysteine and cystine; Monoamino dicarboxylic acids such as aspartic acid and glutamic acid; Diaminomonocarboxylic acids such as lysine; such as P-hydroxyphenylglycine, phenylalanine, anthrani Amino acids with an aromatic nucleus such as acids: Amino acids with a heterocycle such as tryptophan and proline: Aliphatic aminosulfonic acids such as sulfamic acid and cyclohexylsulfamic acid: For example, ethylenediaminetetraacetic acid, nitrilotriacetic acid,
(Poly)aminopolyacetic acids such as iminodiacetic acid, hydroxyethyliminodiacetic acid, hydroxyethylethylenediaminetriacetic acid, ethylenediaminediacetic acid, cyclohexanediaminetetraacetic acid, diethylenetriaminepentaacetic acid, glycol etherdiaminetetraacetic acid; and one of the acid groups of these compounds An intermediate layer partially or entirely composed of a sodium salt, a kawaram salt, an ammonium salt, etc. is provided for the purpose of improving the adhesion between the substrate and the photoconductive layer, the electrostatic properties, dissolution properties, and/or printing properties of the photoconductive layer. be able to.

Further, an overcoat layer that can be dissolved when the photoconductive layer is removed can be provided on the photoconductive layer, if necessary, for the purpose of improving the electrostatic properties of the photoconductive layer, the development properties during toner development, or the image properties. This overcoat layer may be mechanically matted or a resin layer containing a matting agent. As matting agents, silicon dioxide, zinc oxide, titanium oxide, zirconium oxide, glass particles,
Alumina, starch, polymer particles (e.g. particles of polymethyl methacrylate, polystyrene, phenolic resins, etc.) and those described in U.S. Pat. No. 2,710,245 and U.S. Pat. No. 2,992,101 Contains matting agents. Two or more of these can be used in combination. The resin used in the resin layer containing the matting agent is appropriately selected depending on the combination with the etching solution used. Specifically, for example, gum arabic, glue, gelatin, casein, cellulose (such as viscose,
Methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl methyl cellulose,
carboxymethyl cellulose, etc.), starches (e.g. soluble starch, modified starch, etc.), polyvinyl alcohol, polyethylene oxide, polyacrylic acid, polyacrylamide, polyvinyl methyl ether, epoxy resin, phenolic resin (especially preferred is novolac type phenolic resin)
, polyamide, polyvinyl butyral, etc.

In the present invention, when processing a large number of electrophotographic photoreceptors (lithographic printing plate precursors) on which toner images are formed on photoconductive layers by the electrophotographic process described above, each master plate is processed in the following manner. Measure the AC impedance of the treatment liquid. For this reason, the treatment liquid used in the present invention needs to have conductivity to the extent that its AC impedance can be measured, but any alkaline aqueous solution mentioned above or an alkaline aqueous solution containing an organic solvent can be used effectively. Can be done.

In the present invention, as a method for measuring the AC impedance value of the processing liquid, known means such as an AC impedance meter, an AC bridge meter, or other impedance meter can be used.

In addition, the optimum conditions for the measurement current value and oscillation frequency of the measuring device vary depending on the composition of the processing solution, etc., but the current value should be kept low to some extent for the sake of the device and to prevent electrolysis of the aqueous processing solution. Preferably, the range is from several 100 milliamps to several microamps.

In addition, the frequency is determined from the relationship with the capacitance component in the processing liquid.
Several 1001 tz to several 100 Kl (Z is preferred.

The impedance value of a processing solution containing an electrolyte such as an alkaline compound depends on the temperature of the processing solution, and as the solution temperature rises, the impedance value decreases. Therefore, it is more preferable to use a measuring device equipped with a temperature sensor and a temperature guarantee circuit.

The sensor installation position of the AC impedance meter, AC bridge meter, or other impedance meter may be any place where it is immersed in the developing solution during measurement and can measure the AC impedance value of the processing solution, for example, in the processing solution m of an automatic processing machine. A preferred location is in a ring system, especially in a processing tank or in a circulation vibrator.

Further, as the detection section, a known cell having electrodes made of platinum, stainless steel, etc. can be used.

Generally, the impedance value of the processing solution increases due to processing fatigue caused by processing the original plate and carbon dioxide fatigue over time, but during running, the pH of the processing solution remains constant due to repeated recovery of processing solution activity by replenishing the replenisher. Although the impedance value of commonly used replenisher is low, the initial (preparation)
As the replacement rate for the processing liquid increases, the impedance value of the processing liquid tends to decrease, and eventually reaches the impedance value when it is completely replaced by the developer replenisher. A feature of the present invention is that the measured impedance value and
A correction impedance value is obtained by substituting the replenishment liquid replacement rate into a predetermined arithmetic expression, and the replenishment liquid is refilled when the correction impedance value reaches a certain value.

In other words, the measured impedance value is corrected according to a predetermined calculation formula based on the amount of replenishment liquid, and replenishment begins when the corrected impedance value reaches a predetermined value due to exhaustion of the processing liquid. . This arithmetic expression can be obtained experimentally.

In other words, when a large number of toner-developed electrophotographic photoreceptors are printed with a gray scale after being charged and exposed, a replenisher is added so that the resulting printing plate always prints the same number of peta plates or clear plates. What is necessary is to plot the relationship between the replenisher replacement rate and the AC impedance value when replenishing the replenisher. For example, when an aqueous solution of sodium silicate or potassium silicate, potassium hydroxide, and ethanol is used as the treatment liquid, the calculation formula is as follows.

Y=X-(-axll+b-c) Slope of impedance value (b-
c) b = initial impedance value c = ffk Final impedance value (impedance value when the processing solution charged in the developing tank is completely replaced with replenisher) A: Initial processing solution amount B: One replenishment Amount n: Number of times of replenishment Note that the type of processing liquid: Variables i and c are preferably changed automatically or manually depending on changes in the atmosphere (cozy degree, water evaporation, etc.).

In the present invention, the electrical conductivity may be measured instead of the impedance of the processing solution as described above, and when measuring the electrical conductivity of the processing solution, the replenishment solution can be automatically replenished by performing almost the same operation as above. can.

In addition, when the above-mentioned processing is carried out for a long time, the water in the processing liquid evaporates and the processing liquid gradually becomes concentrated.
When performing stable processing using a more stable processing composition than when processing a multi-plate electrophotographic photoreceptor, it is preferable to replenish the above-mentioned replenisher as well as water equivalent to the amount of water evaporated from the processing solution.

In this aspect of the present invention, the method of replenishing the evaporated water content of the processing liquid is to preliminarily calculate the amount of water evaporation of the processing liquid charged into the automatic processing machine by running it in an environment where the automatic processing machine is installed. This is a method of determining the amount of water experimentally and replenishing it continuously or intermittently, automatically or manually, to match the amount of water evaporated.

-S-wise, the amount of water evaporated from the processing liquid is determined by the type of automatic processing machine, the environment in which the automatic processing machine is installed (e.g., temperature, humidity, air volume, etc.), and the operating conditions of the automatic processing machine (e.g., the temperature of the processing liquid, It varies depending on the conveyance speed of the original plate, etc.).

Therefore, if the amount of water evaporation corresponding to each of these conditions is determined experimentally in advance, the amount of water evaporation over time can be automatically calculated, and water corresponding to the amount of water evaporation can be calculated at an appropriate time, e.g. Water may be added at fixed time intervals or every time a specified amount of evaporation is reached. The above-mentioned integration of the amount of moisture evaporation can be automatically performed by detecting the temperature and humidity, for example, by inputting factors such as temperature and humidity conditions, amount of moisture evaporation, and time into a microcomputer.

The amount of water evaporated from the treatment liquid can also be measured using a physicochemical detector such as a hydrometer, liquid level meter, translucency needle, or spectrophotometer. By experimentally determining the relationship with the value detected by the detector, it is possible to automatically or manually replenish water in an amount commensurate with the amount of water evaporated. For example, when using a hydrometer, the relationship between the specific gravity of the treatment liquid and the amount of water evaporated is experimentally determined in advance, and a certain amount of water is added when the specific gravity rises to a predetermined value. .

In this case, if the specific gravity of the replenisher is higher than the specific gravity of the processing solution, it will be impossible to distinguish between the increase in specific gravity due to the addition of the replenisher and the increase in specific gravity due to water evaporation from the developer. By inputting the increase in the specific gravity of the developer due to the addition of the developer replenisher, the amount of water evaporation can be calculated.

Similarly, even when the specific gravity of the processing liquid changes, by inputting the change in specific gravity according to the plate processing amount into a microcomputer or the like, only the amount of water evaporation can be calculated. Addition of water corresponding to the amount of water evaporated thus measured may be carried out in the same manner as described above.

Furthermore, the same method can be used when using other physicochemical detectors.

The automatic processing device used in the present invention is of a type that transports the original, and the processing zone is a normal horizontal transport type equipped with processing liquid spray, brushes, etc., but in particular, it has a dip processing zone. Preferably. Furthermore, a washing zone (including reservoir water circulation), a rinsing zone, a desensitization zone, and a drying zone can be provided as necessary. The replenisher replenishment device includes a replenisher tank and a liquid pump incorporating a timer, or a replenisher that incorporates various programs corresponding to the plate to be processed, the processing liquid, and the replenisher.
Preferably, it consists of a microcomputer, a D/A converter, etc.

〔Example〕

EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited thereto.

Example 1 The surface of a JIS1050 aluminum sheet was grained using a rotating nylon brush using a bamisu water suspension as an abrasive. The surface roughness (center line average roughness) at this time is 0. 5
It was μ. After washing with water, it was immersed in a 10% caustic soda aqueous solution at 70''C and etched so that the amount of aluminum dissolved was 6 g/rd.

After washing with water, it was neutralized by immersing it in a 30% nitric acid aqueous solution for 1 minute, and was thoroughly washed with water. Thereafter, electrolytic electrolysis was carried out for 20 seconds in a 0.7% nitric acid aqueous solution using a rectangular alternating waveform with an anode special voltage of 13 volts and a cathode special voltage of 6 volts (as described in Japanese Patent Publication No. 55-19191). , 50°C in 20% sulfuric acid
After washing the surface by immersing it in a solution, it was washed with water. Furthermore,
Anodized film weight in 20% sulfuric acid aqueous solution is 3.0g/r
A substrate was prepared by performing anodization treatment to achieve RF, washing with water, and drying.

The following photoconductive layer coating solution was applied onto this substrate using a bar coater and dried at 120°C for io minutes to prepare a photoreceptor for electrophotographic engraving.

Coating liquid for photoconductive layer Hydrazone compound shown below 25 parts Copolymer of benzyl memetharylate and methacrylic acid (30 mol% methacrylic acid) 75 parts Thiopyrylium salt compound shown below 1.18 parts Methylene chloride
51.0 parts Methylcellosolve acetate 15
0 parts The dry film thickness of the photoreceptor for electrophotographic engraving thus prepared was 4 μm. A large number of such photoreceptors were produced.

Next, this sample was charged with a surface potential of ++ using a corona charger in a dark place.
After being charged to 400 μm, a clear positive image could be obtained by exposing it to tungsten light and developing it with a liquid developer Ricoh MRP (Ricoh Co., Ltd.). Furthermore, the created image was heated at 120'C for 2 minutes to fix the toner image.

A large number of electrophotographic photoreceptors (lithographic printing plate precursors) on which toner images were formed in this manner were processed using a processing apparatus as illustrated in FIG.

Potassium silicate (Stow/20=
1.24) A treatment liquid consisting of a 3.0% by weight aqueous solution was
I prepared it. Due to the water in the replenishment tank 16, the treatment replenishment liquid in the replenishment tank 17 is potassium silicate (Sioz/KzO=1.24), which has a lower impedance value than the above treatment liquid6.
The discharge amount of pumps 12 and 13 was adjusted so that a 5% by weight aqueous solution was obtained. A detection sensor 14 is set in the circulation system in which the processing liquid in the processing tank 11 is sprayed and circulated from the spray pipe 8 by the pump 10, and the AC impedance value X measured here is substituted into the following calculation formula by the controller 15 to calculate the correction impedance. The value Y is calculated, and when this corrected impedance value Y reaches the replenishment setting level 1Ωcm or more, the developer replenisher and water are pumped by the pump 12.13 to a total of 50%
0cc is now replenished.

Y=-X-(-a x11+b-c)=X (6x
a+6) Ib 10, υ b - 50 Ωcm c = 25 Ωcm a = 50 - 25 = 25 Ωcm A plate of 1003 mm x 800 mm was treated in the above manner for about 1 month. A printing plate with stable halftone dot reproducibility was obtained even after processing 2000 sheets.

Comparative Example 1 The same process as in Example 1 was carried out using the same device as in Example 1, except that the AC impedance value was not corrected, that is, the impedance value for issuing a command to add replenisher was fixed at the initial impedance value. Ta. 1003mmX810O
Although 100 plates of No. 3 were processed, halftone dot reproducibility was poor and only printed matter with stains was obtained.

Example 2 The same operation as in Example 1 was carried out while replenishing water to the treatment liquid as follows.

Since the temperature and relative humidity of the room where the treatment machine was installed were 25°C and 50%, water was replenished at 50 m1/hour while the treatment machine was in operation, based on the amount of water evaporation determined experimentally in advance. When the treatment machine is stopped, the controller 15 is manually refilled so that water is replenished at a rate of 10ml/hour, and 200ml of water is supplied every 4 hours while the treatment machine is in operation, and
0m! ! of water was added by operating pump 12.

A plate measuring 1003 mm x 800 mm was treated as described above for about 6 months. A printing plate with stable halftone dot reproducibility was obtained even after processing 12,000 sheets.

〔Effect of the invention〕

According to the present invention, it is possible to stably process a large number of electrophotographic printing plate precursors for a long period of time without deterioration of the processing solution or change in composition, and to provide excellent planographic printing plates. Can be done.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view showing one example of a processing apparatus used in the method of the present invention. L 3.4.5.6... Conveyance roll 2.7...
... Guide roll 8.9 ... Spray 10.21 ... Circulation pump 14 ... Processing liquid impedance value detection sensor 15 ... Impedance controller 18・
... Filter 12.13 ... Replenishment pump 16 ... Water 17 ... Processing replenisher 11 ... Processing liquid 23 ...・Floating fish A...Processing zone B...Rinse zone procedure amendment March 7, 1999

Claims (2)

[Claims] (1) In a processing method for removing a non-image area of a lithographic printing plate precursor, the image area is a toner image formed by an electrophotographic process on a photoconductor layer provided on a conductive substrate. The deterioration of the processing solution for removing the water is detected by measuring the conductivity or impedance of the processing solution, and the replenishing solution is automatically added to the processing solution according to pre-programmed instructions and/or correction calculation formulas. A method for processing an original plate for an electrophotographic lithographic printing plate, the method comprising: compensating for the deterioration. (2) In a processing method for removing a non-image area of a lithographic printing plate precursor, the image area is a toner image formed by an electrophotographic process on a photoconductor layer provided on a conductive substrate. The deterioration of the processing solution for removing the water is detected by measuring the conductivity or impedance of the processing solution, and the replenishing solution is automatically added to the processing solution according to pre-programmed instructions and/or correction calculation formulas. A method for processing an electrophotographic printing plate precursor, comprising: compensating for the deterioration by continuously or intermittently adding water corresponding to the amount of water evaporated from the processing solution over time.