JPH06124007A - Correcting agent for electrophotographic planographic printing plate - Google Patents

Abstract

PURPOSE:To provide the correcting agent and a correction processing method capable of rapidly correcting the unnecessary part of an electrophotographic made planographic printing plate. CONSTITUTION:This correcting agent contains (1) an org. solvent swelling or dissolving at least toners and (2) an org. solvent and/or alkaline compd. dissolving or swelling a photoconductive layer and, if necessary, water and thickener at the time of correcting a part of the image part of the planographic printing plate obtd. by a stage for forming at least the toner images, a stage for fixing the toner image and a stage for removing the photoconductive layer exclusive of the toner images on the electrophotographic planographic printing plate formed by providing the surface of a conductive substrate with the photoconductive layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic lithographic printing plate which is used as a printing plate by forming a toner image on a photoconductive layer and then removing non-image areas other than the toner image area (hereinafter referred to as etching). The present invention relates to a printing plate correction processing method and a correction agent.

[0002]

2. Description of the Related Art Today, as a lithographic offset printing plate,
A positive-type photosensitizer containing a diazo compound and a phenol resin as a main component and a PS plate using a negative-type photosensitizer containing an acrylic monomer or a prepolymer as a main component have been put into practical use, but all of them have low sensitivity. A film original plate on which an image is recorded in advance is contact-exposed to perform plate making.
On the other hand, due to the progress of computer image processing, storage of large amount of data, and data communication technology, in recent years, computer operations are consistently performed from manuscript input, correction, editing, layout to page setting, and immediate remote communication is achieved by high-speed communication network and satellite communication. An electronic editing system that can output to the terminal plotter of the ground has been put to practical use. In particular, there is a high demand for electronic editing systems in the field of newspaper printing, where immediacy is required. Also, in the field where the original manuscript is currently stored in the form of a film and the printing plate is reproduced as needed based on this,
With the development of large-capacity recording media such as optical discs, it is considered that the originals will be stored as digital data in these recording media. However, direct type printing plates, which directly produce printing plates from the output of end plotters, have hardly been put to practical use, and even when the electronic editing system is in operation, the output is performed on the silver halide photographic film, and this PS plate is used. The actual situation is that a printing plate is produced by exposing the plate to contact. This is the light source of the output plotter (eg He-Ne laser,
One of the causes is that it is difficult to develop a direct type printing plate having a high sensitivity for producing a printing plate in a practical time by using a semiconductor laser or the like.

An electrophotographic photoreceptor is considered as a photoreceptor having high photosensitivity that can provide a direct printing plate. As a method of making a printing plate using electrophotography, a method of removing a photoconductive layer in a non-image area after forming a toner image is already known. For example, Japanese Examined Patent Publication Nos. 37-17162 and 38-6.
No. 961, No. 38-7758, No. 41-2426,
46-39405, JP-A-50-19509, 50-19510, 52-2437, 54-1.
45538, 54-134632, 55-10.
No. 5254, No. 55-153948, No. 55-161.
No. 250, No. 57-147656, No. 57-1618
The printing original plate for electrophotographic plate making described in JP-A No. 63, etc. may be mentioned. In the above method, a binder resin that dissolves in an alkaline solvent or that swells and releases is used as the binder resin for the electrophotographic photoreceptor, and the hydrophilic surface is exposed by removing the toner image other than the toner image portion as a resist. ,
The planographic printing plate is used.

In manufacturing the printing plate, an image portion that needs to be deleted and corrected may occur. For example, when surface exposure is performed in the same manner as the PS plate, uneven exposure due to stains, scratches, cuts, and sticking marks on the original film, and scratches, dust, etc. on the plate surface even during laser exposure etc. Causes an unnecessary image portion. In the electrophotographic lithographic printing plate, JP-A-1-134468 has been proposed to correct an unnecessary image portion.
In the same publication, it is shown that the unnecessary image portion is erased by removing the unnecessary toner image on the plate surface between the step of forming the toner image and the step of removing the photoconductor layer in the non-image area. Has been done. However, in the case of electrophotographic plate making, the process from charging to etching is often performed in a consistent manner. Therefore, in the above method, the photosensitive material during plate making had to be taken out on the way, and in many cases it could not be practically used. Further, the plate before fixing the toner will be scratched by a slight touch and cannot be used. Further, generally, in electrophotographic plate making, the contrast between the image area and the photoconductor layer is often small, and it was very difficult to find an image to be corrected. Therefore, it is practically desired to correct the image after the completion of plate making, but the present situation is that there is no correction agent useful for electrophotographic lithographic printing plates. The existing lithographic printing plate modifier using a photopolymer is useful for correcting an image composed of a single photosensitive layer, but the image of an electrophotographic lithographic printing plate composed of a toner and a photosensitive layer having different properties is used. Was inappropriate to fix.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide an electrophotographic lithographic printing plate precursor having a photoconductive layer provided on a conductive substrate, at least a step of forming a toner image, a step of fixing the toner image, and a toner image. Another object of the present invention is to provide a method for correcting a part of an image portion of a lithographic printing plate obtained by a step including a step of removing a photoconductive layer other than the above with a correcting agent, and the correcting agent. Another object of the present invention is to provide a correction agent that can quickly correct unnecessary portions without taking out the photosensitive material from the processor during plate making. Still another object of the present invention is to provide an electrophotographic lithographic printing plate having excellent print quality.

[0006]

Means for Solving the Problems As a result of intensive studies of the present invention, at least in the step of forming a toner image and fixing the toner image in an electrophotographic lithographic printing plate precursor having a photoconductive layer provided on a conductive substrate. When a part of the image portion of the lithographic printing plate obtained by the step including the step of removing the photoconductive layer other than the toner image is subjected to a correction treatment with the correction agent, the correction agent (1) swells at least the toner or A method for correcting an electrophotographic lithographic printing plate, which comprises at least one selected from the group consisting of an organic solvent that dissolves and (2) an organic solvent that dissolves or swells a photoconductive layer and an alkaline compound, and The above-mentioned object could be achieved by the correction agent.

The present invention will be described in detail below. The electrophotographic lithographic printing plate of the present invention can be prepared by forming a toner image, fixing, and removing the photoconductive layer in the non-image area by a conventionally known method. That is, it is charged substantially uniformly in a dark place, and an electrostatic latent image is formed by imagewise exposure. As the exposure method, scanning exposure using a semiconductor laser, a He-Ne laser or the like, a xenon lamp, a tungsten lamp,
Reflective image exposure using a fluorescent lamp or the like as a light source, contact exposure through a transparent positive film, and the like can be mentioned. Next, the electrostatic latent image is developed with toner. As the developing method, conventionally known methods, for example, various methods such as escade developing, magnetic brush developing, powder cloud developing, liquid developing and the like can be used. Among them, liquid development is capable of forming a fine image and is suitable for making a printing plate. Further, either a normal image in which toner is attached to the non-exposed portion or a reversal development method in which toner is attached to the exposed portion can be used. The formed toner image can be fixed by a conventionally known fixing method, for example, heat fixing, pressure fixing, solvent fixing or the like. A lithographic printing plate can be prepared by causing the toner image thus formed to act as a resist and removing the electrophotographic photosensitive layer in the non-image area with an etching solution. As a post-etching step, a washing step, a gumming step, a drying step, a pattern recognizing step equipped with a CCD sensor or the like for pattern recognition, a bender and a punch step for processing a printing plate into a predetermined shape, a plate accumulating step, etc. Can be provided.

As the photoconductive material used in the present invention, many conventionally known compounds can be used. For example, triazole derivative, oxadiazole derivative, imidazole derivative, polyarylalkane derivative, pyrazoline derivative, pyrazolone derivative, phenylenediamine derivative, arylamine derivative, amino-substituted chalcone derivative, N, N-bicarbazyl derivative, oxazole derivative, styrylanthracene derivative , Fluorenone derivatives, hydrazone derivatives, benzidine derivatives, stilbene derivatives and the like. In addition to the low molecular weight photoconductive compounds as described above, the following high molecular compounds can also be used. For example, polyvinyl carbazole and its derivatives, polyvinyl pyrene, polyvinyl anthracene, poly-2-vinyl-4- (4'-dimethylaminophenyl) -5-phenyloxazole, poly-3-vinyl-N-ethyl cambazole, and other vinyls. Examples thereof include polymers, polymers such as polyacenaphthylene, polyindene, copolymers of acenaphthylene and styrene, and condensation resins such as pyrene-formaldehyde resin, bromopyrene-formaldehyde resin, and ethylcarbazole-formaldehyde resin.

Various charge generating agents, sensitizing dyes, etc. can be used for the purpose of improving the sensitivity of the photoconductor and providing a desired photosensitive wavelength range. Examples of these include monoazo, bisazo, trisazo pigments, phthalocyanine pigments such as metal phthaloanine or metal-free phthalocyanine, and naphthalocyanine, perylene pigments,
Indigo, thioindigo derivative, quinacridone pigment,
Examples thereof include polycyclic quinone pigments, bisbenzimidazole pigments, squalium salt pigments, and azulenium salt pigments. Further, as the sensitization charge, "sensitizer", page 125, Kodansha (1987), "electronic photography", page 12, page 9
(1973) "Organic Synthetic Chemistry" Vol. 24 No. 11
Known compounds described on page 1010 (1966) can be used. For example, there are pyrylium dyes, triarylmethane dyes, cyanine dyes, styryl dyes and the like. In the photoconductive layer of the present invention, an electron-withdrawing compound such as trinitrofluorenone, chloranil, or tetracyanoethylene can be used for the purpose of improving sensitivity. The above materials can be used alone or in combination of two or more kinds. Further, the charge generating agent is
In the case of having not only charge generating ability but also charge transporting ability, a photoreceptor can be prepared by dispersing and applying the charge generating agent in a binder as a basic material. That is, it is not always necessary to use the organic photoconductive compound known as a charge transport agent together. Further, the photoconductive layer may be formed of a single layer or a plurality of layers, if necessary.

The binder resin used in the electrophotographic plate-like printing original plate of the present invention is not particularly limited as long as it can remove the non-image area with an etching solution after toner development. As the etching liquid, the alkaline liquid described below is preferable, and when this is used, the following can be exemplified. For example, containing monomers such as (meth) acrylic acid ester, styrene, vinyl acetate and carboxylic acid such as (meth) acrylic acid, itaconic acid, crotonic acid, maleic acid, maleic anhydride, maleic anhydride monoalkyl ester, fumaric acid Examples thereof include a copolymer with a monomer or an acid anhydride group-containing monomer. More specifically, styrene / maleic anhydride copolymer, styrene / maleic anhydride monoalkyl ester copolymer, (meth) acrylic acid / (meth)
Acrylic ester copolymer, styrene / (meth) acrylic acid / (meth) acrylic acid ester copolymer, vinyl acetate / crotonic acid copolymer, vinyl acetate / crotonic acid /
(Meth) acrylic acid ester copolymer, vinyl acetate / C
Examples thereof include vinyl ester / crotonic acid copolymers of 2 to 18 carboxylic acids. Further, a copolymer containing a monomer having (meth) acrylic acid amide, vinylpyrrolidone, a phenolic hydroxyl group, a sulfonic acid group, a sulfonamide group, a sulfonimide group, phenol, o-cresol, m-cresol or p- A novolak resin obtained by condensing cresol and formaldehyde or acetaldehyde, a partially saponified vinyl acetate resin, a polyvinyl acetal resin such as polyvinyl butyral, and a polyurethane resin having a carboxylic acid can also be preferably used.

More preferably, a copolymer of (meth) acrylic acid ester, styrene, vinyl acetate and the like and a carboxylic acid-containing monomer is excellent in electrophotographic property, etching property and printability and can be preferably used. . More preferably, methyl alcohol, ethyl alcohol, propyl alcohol, isopropyl alcohol, butyl alcohol, isobutyl alcohol, sec-butyl alcohol, tert-butyl alcohol, n-amyl alcohol, isoamyl alcohol, hexyl alcohol, octyl alcohol, benzyl alcohol, phenethyl alcohol. (Meta) of aliphatic or aromatic alcohols such as
Copolymers of acrylic acid esters and (meth) acrylic acid can be used.

Various supports can be used as the electroconductive substrate of the electrophotographic printing original plate of the present invention. For example, a plastic sheet with a conductive surface or especially a solvent-impermeable and conductive paper, an aluminum plate,
Zinc plate, bimetal plate such as copper-aluminum plate, copper-stainless plate, chrome-copper plate, etc., or hydrophilic property such as chrome-copper-aluminum plate, chrome-lead-iron plate, trimetal plate such as chrome-copper-stainless plate, etc. A conductive substrate having a conductive surface is used, and the thickness thereof is preferably 0.1 to 3 mm, particularly preferably 0.1 to 0.5 mm. Among these substrates, the aluminum plate is preferably used. In the present invention, the aluminum plate used for the electrophotographic printing original plate is a plate-like body such as pure aluminum containing aluminum as a main component or an aluminum alloy containing a slight amount of a foreign atom, and its composition is not specified and is conventionally known. , Official materials can be used as appropriate. This aluminum plate can be used after graining and anodizing by a conventionally known method. Prior to the graining treatment, a resin treatment with a surfactant or an alkaline aqueous solution is applied if desired in order to remove rolling fat on the surface of the aluminum plate, and the graining treatment is performed. The graining treatment method includes a method of mechanically roughening the surface, a method of electrochemically melting the surface, and a method of chemically selectively melting the surface. As a method for mechanically roughening the surface, a known method called a ball polishing method, a brush polishing method, a blast polishing method, a buff polishing method or the like can be used. As an electrochemical graining method, there is a method of performing alternating current or direct current in a hydrochloric acid or nitric acid electrolytic solution. Further, as disclosed in Japanese Patent Laid-Open No. 54-63,902, a method in which both are combined can be used.

The roughened aluminum plate is subjected to alkali etching treatment and neutralization treatment, if necessary. The aluminum plate thus treated is anodized. As the electrolyte used for the anodizing treatment, sulfuric acid, phosphoric acid, oxalic acid, chromic acid, or a mixed acid thereof is used, and the electrolyte and the concentration thereof are appropriately determined depending on the kind of the electrolyte. Since the treatment conditions of anodization vary variously depending on the electrolyte used, it cannot be unconditionally specified, but generally, the concentration of the electrolyte is 1 to 80 wt% solution, the liquid temperature, 5 to 70 ° C., and the current density is 5 to 60 A. / Dm ² , voltage 1 to 100 V, and electrolysis time of 10 seconds to 50 minutes are preferable. The amount of anodized film is preferably 0.1 to 10 g / m ^2, but more preferably 1 to 6 g / m ² . The thickness of these aluminum plates is preferably 0.1 to 3 mm, and particularly preferably 0.
1 to 0.5 mm is preferable. Furthermore, Japanese Examined Japanese Patent Publication No. 47-512
It is also preferable to use an aluminum plate as described in Japanese Patent Publication No. 5 which is anodized and then immersed in an aqueous solution of an alkali metal silicate. Also, US Patent No. 3
The silicate electrodeposition as described in the specification of 658662 is also effective. Treatment with polyvinyl sulfonic acid as described in West German Patent No. 16214478 is also suitable.

The electrophotographic printing plate of the present invention can be obtained by coating a photoconductive layer on an aluminum substrate according to a conventional method. In producing the photoconductive layer, a method of incorporating the components constituting the photoconductive layer in the same layer, a method of separating the charge carrier generating substance and the charge carrier transporting substance into different layers, and the like are known. You can also create by the method of. The coating liquid is prepared by dissolving each component constituting the photoconductive layer in a suitable solvent. When a component such as a pigment that is insoluble in a solvent is used, it is dispersed in a particle size of 5 μm or less by a dispersing machine such as a ball mill, a paint shaker, a dyno mill, or an attritor. The binder resin and other additives used in the photoconductive layer can be added during or after the dispersion of the pigment or the like. The coating solution thus prepared is coated on a substrate by a known method such as spin coating, blade coating, knife coating, reverse roll coating, dip coating, rod bar coating, spray coating, and dried to prepare an electrophotographic printing plate precursor. Can be obtained. As a solvent for forming the coating liquid, dichloromethane, dichloroethane, halogenated hydrocarbons such as chloroform, methanol,
Alcohols such as ethanol, ketones such as acetone, methyl ethyl ketone and cyclohexanone, glycol ethers such as ethylene glycol monomethyl ether and 2-methoxyethyl acetate, tetrahydrofuran,
Examples thereof include ethers such as dioxane, esters such as ethyl acetate and butyl acetate, and the like. In the photoconductive layer of the present invention, in addition to the photoconductive compound and the binder resin, a plasticizer, a surfactant, a matting agent and other various kinds of additives may be added as necessary in order to improve the flexibility of the photoconductive layer and the surface condition of the coating. Additives can be added. These additives can be contained within a range that does not deteriorate the electrostatic characteristics and etching properties of the photoconductive layer. If the film thickness of the photoconductive layer of the present invention is too thin, the surface potential required for development cannot be charged, and conversely, if it is too thick, side etching easily occurs and a good printing plate cannot be obtained. . The film thickness of the photoconductive layer is 0.1 to 30 μm, preferably 0.5 to 10 μm. Regarding the contents of the binder resin and the photoconductive compound in the photoconductive layer of the present invention, the sensitivity is lowered when the content of the photoconductive compound is small, so that the photoconductive compound is 0.02 per 1 part by weight of the binder resin. 1.2 parts by weight
It is preferable to use it in a range of 0.05 part by weight, more preferably 0.05 part by weight to 1.0 part by weight.

In the electrophotographic printing plate precursor of the present invention, an intermediate layer may be provided, if necessary, for the purpose of improving the adhesion between the aluminum substrate and the photoconductive layer, the electrical characteristics of the photoconductive layer, the etching property, the printing characteristics and the like. Can be provided. Also,
If necessary, an overcoat layer that can be removed during etching of the photoconductive layer can be provided on the photoconductive layer for the purpose of improving the electrical characteristics of the photoconductive layer, the image characteristics during toner development, the adhesion with toner, and the like. The overcoat layer may be a mechanically matted layer or a resin layer containing a matting agent. Specifically, Japanese Patent Application No. 3-9266
Various materials described in Japanese Patent Publication No. 1 and the like can be used.

In the present invention, the resin component of the toner forming the image portion is not particularly limited as long as it has a resist property with respect to the etching liquid described later, but the following resins are exemplified. You can For example, acrylic resins using methacrylic acid, acrylic acid and their esters, vinyl acetate resins, copolymer resins of vinyl acetate and ethylene or vinyl chloride, vinyl chloride resins, vinylidene chloride resins, vinyl acetal resins such as polyvinyl butyral. , Polystyrene, copolymer resins such as styrene and butadiene and methacrylic acid esters, polyethylene, polypropylene and chlorinated products thereof, polyester resins (for example, polyethylene terephthalate, polyethylene isophthalate, bisphenol A polyebonates, etc.), phenol resins, xylene resins. , Alkyd resins, vinyl-modified alkyd resins, gelatin, cellulose ester derivatives such as carboxymethyl cellulose, wax, polyolefin, wax and the like. More preferably, especially from the viewpoint of dispersibility or etching resistance, acrylic resins using various esters of methacrylic acid and acrylic acid, copolymer resins of methacrylic acid and various esters of acrylic acid with styrene, styrene resins, vinyl acetate. Resins and the like can be used.

As the etching liquid for removing the photoconductive insulating layer in the non-image portion of the toner after the toner image is formed, any solvent can be used as long as it can remove the photoconductive insulating layer, and is not particularly limited. However, preferably an alkaline solvent is used. The alkaline solvent mentioned here is an aqueous solution containing an alkaline compound, an organic solvent containing an alkaline compound, or a mixture of an aqueous solution containing an alkaline compound and an organic solvent. As the alkaline compound, sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, potassium silicate, lithium silicate, sodium metasilicate, potassium metasilicate, sodium phosphate, potassium phosphate, ammonia and monoethanolamine, The organic and inorganic arbitrary alkaline compounds such as diethanolamine, triethanolamine, monoisopropanolamine, triisopropanolamine, diethylaminoethanol, and 2-amino-2-methylpropanol can be mentioned. Among them, especially, the general formula mSiO ₂ / nM ₂ O
By including the silicate represented by (M: alkali metal atom, m / n = 0.5 to 8.5) in the etching solution, better etching properties and printing characteristics can be obtained. If necessary, various organic solvents can be added to the etching solution mainly containing water. Preferred organic solvents include methanol, ethanol, propanol, butanol, benzyl alcohol, lower alcohols such as phenethyl alcohol and aromatic alcohols and polyhydric alcohols such as ethylene glycol, diethylene glycol, triethylene glycol and polyethylene glycol, ether alcohols, Organic solvents such as ether esters, ethers, ketones, and esters, surfactants, defoaming agents, and various other additives can be contained.

The correction agent of the present invention (hereinafter sometimes referred to as a correction liquid) is (1) at least an organic solvent capable of swelling or dissolving a toner and (2) an organic solvent capable of dissolving or swelling a photoconductive layer and / or an alkaline compound, If necessary, it is composed of water and a thickener. The organic solvent that swells or dissolves the toner allows the component that removes the photoconductive layer to quickly permeate and allows the correction to be quickly performed. The organic solvent is appropriately selected depending on the toner component, but as the toner, acrylic resin using various esters of methacrylic acid and acrylic acid, copolymer resin of styrene with various esters of methacrylic acid and acrylic acid, styrene resin, vinyl acetate When a resin based resin is used, examples thereof include lactones, ethers, ketones, alcohols and hydrocarbon solvents. The lactones include butyrolactone, valerolactone, hexanolactone, and the like, and the ethers include glycol ethers. For example, 2-methoxyethanol, 2-ethoxyethanol, 2-isopropoxyethanol, glycol monoalkyl ethers such as 2-butyl glycol, for example, glycol monoaryl ethers such as 2-phenylethanol, for example,
Diethylene glycol monoalkyl ethers such as diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monoisopropyl ether, diethylene glycol monobutyl ether, diethylene glycol monoisobutyl ether, for example, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monobutyl ether And triethylene glycol monoalkyl ethers such as ethylene glycol dialkyl ethers such as ethylene glycol dimethyl ether, and diethylene glycol dialkyl ethers such as diethylene glycol dimethyl ether and diethylene glycol diethyl ether.

Examples of the ketones include methyl ethyl ketone, methyl propyl ketone, diethyl ketone, methyl butyl ketone, methyl isobutyl ketone, ethyl butyl ketone, butyrone, methyl amyl ketone, methylhexyl ketone, valerone, mesityl oxide, diacetone alcohol, Cyclohexanone, methylcyclohexanone,
Acetophenone, isophorone, acetylacetone, acetonylacetone, etc. are included. Examples of alcohols include ethanol, butanol, octyl alcohol, and benzyl alcohol. Examples of the hydrocarbon solvent include petroleum fractions such as toluene, xylene, turpentine oil, n-heptane, solvent naphtha, kerosene, and mineral spirits having a boiling point of 120 to 250 ° C. In addition to these, N, N-dimethylformamide, tetrahydrofuran, dioxane, N
-Methylpyrrolidone, dimethyl sulfoxide and the like can also be mentioned. The above solvents may be used alone or in combination of two or more.

As the organic solvent and / or alkaline compound that dissolves or swells the photoconductive layer of the present invention, in addition to the above organic solvent, alkaline compounds such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, and silicic acid can be used. Potassium, lithium silicate, sodium metasilicate, potassium metasilicate, sodium phosphate, potassium phosphate, ammonia and monoethanolamine,
The organic and inorganic arbitrary alkaline compounds such as diethanolamine, triethanolamine, monoisopropanolamine, triisopropanolamine, diethylaminoethanol, and 2-amino-2-methylpropanol can be mentioned. Of these, monoethanolamine, triethanolamine, diethylaminoethanol, and silicates represented by the general formula mSiO ₂ / nM ₂ O (M: alkali metal atom, m / n = 0.5 to 8.5) are particularly preferable. Can be used for

In the present invention, a thickener is used as necessary to prevent the correction liquid from eroding the uncorrected portion and to prevent the correction brush from dripping. Examples of the thickener include inorganic thickeners such as silicic acid fine powder, for example, modified cellulose such as methyl cellulose, hydroxymethyl cellulose, hydroxypropyl methyl cellulose and carboxymethyl cellulose, gum arabic, polyvinylpyrrolidone, polyvinyl methyl ether, polyethylene glycol, polypropylene. Polymer compounds such as glycol, vinyl methyl ether / maleic anhydride copolymer, vinyl acetate / maleic anhydride copolymer and the like can be mentioned. Among these, fine powder of silicic acid, modified cellulose such as hydroxymethyl cellulose and hydroxypropyl methyl cellulose, and polyvinylpyrrolidone can be preferably used. These thickeners can be used alone or in combination of two or more.

A surfactant may be added to the correction fluid of the present invention, if necessary. The surfactant is effective for promoting better penetration into the image area and further for mixing well the respective components contained in the correction agent to form a stable solution or dispersion. Although various kinds of surfactants can be mentioned, nonionic surfactants include polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene polystyryl phenyl ethers, polyoxyethylene polyoxypropylene alkyls. Ether, glycerin fatty acid partial ester, sorbitan fatty acid partial ester, pentaerythritol fatty acid partial ester, propylene glycol monoglycerin fatty acid partial ester, sucrose fatty acid partial ester, oxyethyleneoxypropylene block copolymer, polyoxyethylene sorbitan fatty acid partial ester , Polyoxyethylene sorbitol fatty acid partial esters, polyethylene glycol fatty acid partial esters, polyglycerin fatty acid Ester, polyoxyethylenated castor oil, polyoxyethylene glycerin fatty acid partial ester, fatty acid diethanolamide, N, N-bis-2-hydroxyalkylamines, polyoxyethylene alkylamine, triethanolamine fatty acid partial ester , Trialkylamine oxide and the like.

Examples of the anionic surfactant include fatty acid salts, abietic acid salts, hydroxyalkane sulfonates, alkane sulfonates, dialkylsulfosuccinates, linear alkylbenzene sulfonates, branched chain alkylbenzene sulfonates, and alkylnaphthalenes. Sulfonates, alkylphenoxy polyoxyethylene propylene sulfonates, polyoxyethylene alkylsulfophenyl ether salts, N-methyl-N
-Sodium oleyl taurine, N-sulfosuccinic acid monoamide disodium salt, petroleum sulfonate, sulfated castor oil, sulfated cattle foot oil, sulfate ester salt of fatty acid alkyl ester, alkyl sulfate ester salt, polyoxyethylene alkyl ether sulfate Ester salts, fatty acid monoglyceride sulfuric acid ester salts, polyoxyethylene styryl phenyl ether sulfuric acid ester salts, polyoxyethylene alkylphenyl sulfuric acid ester salts, alkyl phosphoric acid ester salts, polyoxyethylene alkyl ether phosphoric acid ester salts, polyoxyethylene alkylphenyl ether phosphoric acid ester Examples thereof include salts, partially saponified styrene-maleic anhydride copolymers, and naphthalene sulfonate formalin condensates.

Further, alkylamine salts, quaternary ammonium salts, polyoxyethylene alkylamine salts,
A cationic surfactant such as a polyoxyethylene polyamine derivative, a double-sided surfactant such as carboxybetaines, aminocarboxylic acids, sulfobetaines, aminosulfates, and imidazolines can also be used. Among the surfactants mentioned above, some of polyoxyethylene can be replaced with polyoxyalkylenes such as polyoxymethylene, polyoxypropylene, and polyoxybutylene. Among these, nonionic surfactants and anionic surfactants are preferable, and surfactants having a high wettability of 8 or more HLB are advantageous. These surfactants may be used alone or in combination of two or more.

The correction fluid of the present invention may contain various colorants, if desired. Inclusion of a colorant provides visual contrast and makes correction easier. The correction agent of the present invention may contain a hydrophilic polymer, if necessary. The hydrophilic polymer is effective in making the amyl surface hydrophilic and preventing dirt from redepositing. Although various kinds of hydrophilic polymers can be used, the polymers described in US Pat. No. 5,051,327 can be preferably used.

The content of each component in the correction liquid of the present invention is 5% to 85% by weight, preferably 10% to 7% by weight of the organic solvent which swells or dissolves the toner based on the composition of the correction liquid.
0 wt%, 5% organic solvent that dissolves or swells the photoconductive layer
Wt% to 85 wt%, preferably 10 wt% to 70 wt%, alkaline compound 0.1 wt% to 10 wt%
Preferably from 0.3% to 5% by weight, from 1% to 30% by weight of water, preferably from 3% to 20% by weight, from 0.5% to 25% by weight of thickener, preferably from 1% by weight. 5 wt%, 1 wt% to 40 wt% surfactant, preferably 3 wt% to 25 wt%, 0.0001 colorant
Wt% to 0.005 wt%, preferably 0.001 wt% to 0.01 wt%, hydrophilic polymer 0.5 wt%
To 10% by weight, preferably 1% to 5% by weight.

In the plate making of electrophotographic lithographic printing plates, usually, the processes from charging to etching are often carried out in a consistent manner. Therefore, it is best to correct after elution of the photoconductive layer or after gumming, but it is also possible to correct in the steps from toner development to etching. For correction, an appropriate amount of the correction liquid of the present invention may be applied to a brush or the like and applied to the correction portion for correction. Further, it can be corrected more quickly by taking it on a rod-shaped stone, bamboo, water, plastic or the like and mechanically rubbing the toner surface to partially scratch it. After correction, you can use it as it is,
Good results can be obtained by washing with water, hydrophilization, gumming, etc., if necessary.

[0028]

EXAMPLES The present invention will be described in more detail by way of examples, but the present invention is not limited to the following examples unless it exceeds the gist thereof. Example 1 The surface of a JIS 1050 aluminum sheet was grained with a rotating nylon brush using a Bamis-water suspension as an abrasive. The surface roughness (centerline average roughness) at this time is 0.5μ
It was m. After washing with water, it was immersed in a 10% aqueous sodium hydroxide solution at 70 ° C. and etched so that the amount of aluminum dissolved was 6 g / m ² . After washing with water, it was neutralized by immersing in a 30% nitric acid aqueous solution for 1 minute, and thoroughly washed with water. afterwards,
In a 0.7% nitric acid aqueous solution, an alternating rectangular waveform with a voltage of 13 V for the anode and a voltage of 6 V for the cathode was used.
Electrolytic surface roughening was performed for 20 seconds, the surface was washed by immersing it in a solution of 20% sulfuric acid at 50 ° C., and then washed with water. Furthermore, a substrate was prepared by anodizing treatment in a 20% aqueous solution of sulfuric acid so that the weight of the anodized film would be 3.0 g / m ² , washing with water, and drying.
Next, x-type metal-free phthalocyanine Fastogen B
lue 8120 (trade name, manufactured by Dainippon Ink and Chemicals, Inc.)
1.0 g, butyl methacrylate / butyl acrylate / acrylic acid copolymer (35/35/30 mol%)
5.0 g, 1,4-dioxane 76 g, and 2-propanol 18 g were dispersed by a paint shaker (Toyo Seiki Seisakusho Co., Ltd.) for 60 minutes to prepare a photoconductive layer dispersion liquid. The coating liquid for the photoconductive layer was applied onto the substrate with a bar coater and dried at 120 ° C. for 10 minutes to prepare an electrophotographic printing plate having a dry film thickness of 4 μm.

The photosensitive material was charged to a surface potential of +300 V by a corona charger in a dark place, a negative image was exposed with tungsten light, and an electrostatic charge toner (ELP toner manufactured by Fuji Photo Film Co., Ltd.) was used. By applying a bias voltage of +200 V to the counter electrode, a clear positive toner image could be obtained. The printing original plate thus prepared was heat-fixed at 100 ° C., and then 28.0 g of sodium silicate solution (SiO ₂ content 30% by weight, SiO ₂ / Na ₂ O molar ratio 3.0), potassium hydroxide 1. 5g, water 7
The non-image area was removed with an etching solution of 0.5 g. This is washed with water and gummed (water / GU-7 (1/1)
Fuji Photo Film Co., Ltd., a dry offset printing plate was prepared. A correction liquid having the following composition was applied to a part of this image with a brush, and after 10 seconds, it was washed with water and gummed. When this was printed by an offset printing machine, it was possible to obtain a very good printed matter without stains on the corrected portion as well as stains on the peripheral portion to which the correction liquid was attached.

Correction Liquid (1) γ-Butyl Lactone 50.0 g Hydroxypropyl Methyl Cellulose (Metroses 1.5 g 65SH50-Product Name-Shin-Etsu Chemical Co., Ltd.) Oxyethyleneoxypropylene Block Polymer 5.0 g (Bluronic P-85-Product Name-Asahi Denka Kogyo Co., Ltd. Water 10.0 g Benzyl Alcohol 22.0 g Organic Phosphonic Acid (Ferriox 115-Brand Name-) 7.0 g Crystal Violet 0.003 g Powdered Silicon Dioxide (Aerosil # 380-Brand Name-) 4.0 g Nippon Aerosil Co., Ltd. Sodium alkylbenzene sulfonate 0.5 g

Examples 2 and 3 An offset printing plate was prepared by the same procedure except that the following correction liquid was used instead of the correction liquid of Example 1. When this was printed by an offset printing machine, it was possible to obtain a very good printed matter without stains on the corrected portion as well as stains on the peripheral portion on which the correction liquid was adhered, as in Example 1.

Correction Solution (2) A correction solution was prepared in the same manner except that phenethyl alcohol was used instead of benzyl alcohol in the correction solution (1).

Correction Solution (3) A correction solution was prepared in exactly the same manner except that valerolactone was used instead of γ-butyl lactone in the correction solution (1).

Example 4 On the aluminum substrate of Example 1, 1.0 g of ε-type copper phthalocyanine Liophon-ERPC (trade name, manufactured by Toyo Ink Co., Ltd.), a vinyl acetate / crotonic acid copolymer (RESYN 28-2930-) were used. Product name-Kanebo NSC Co., Ltd.) 10.0 g, tetrahydrofuran 60 g, cyclohexanone 40 g are put in a 500 ml glass container together with glass beads, and dispersed for 60 minutes with a paint shaker (Toyo Seiki Seisakusho Co., Ltd.) A conductive layer dispersion liquid was prepared. This photoconductive layer coating liquid was applied onto the substrate with a bar coater and dried at 100 ° C. for 10 minutes to prepare an electrophotographic printing plate precursor having a dry film thickness of 4 μm. The printing plate thus prepared was charged to a surface potential of +300 V by corona charging, and then a printing plate was prepared by a series of steps such as drawing an image area with a semiconductor laser, toner development, fixing, etching, washing with water, gumming, etc. .

Isobar H (trade name of isoparaffin solvent, Esso Standard Co.) 100 is used in the toner developing section.
Polyvinyl acetate particles (particle size 0.2 μm in 0 ml)
m) 6 g was dispersed as toner particles, and a liquid developer prepared by adding 0.01 g of zirconium naphthenate as a charge control agent was charged, and a bias voltage of +200 V was applied to the counter electrode for reverse development. Fuji Photo Film Co., Ltd. PS plate developer DP-4 (trade name) is used in the etching section.
Was diluted 1:20, tap water was used for the washing part, and gum solution GU-7 (trade name) manufactured by Fuji Photo Film Co., Ltd. was diluted 1: 1 with water for the gum part. .

A correction liquid having the following composition was applied to a part of this image with a brush, and after 10 seconds, it was washed with water and gummed. When this was printed by an offset printing machine, it was possible to obtain a very good printed matter without stains on the corrected portion as well as stains on the peripheral portion to which the correction liquid was attached.

Correction Solution (4) γ-Butyl Lactone 50.0 g 3-Propiolactone 15.0 g Hydroxypropyl Methyl Cellulose (Metroses 1.5 g 65SH50-Brand Name-Shin-Etsu Chemical Co., Ltd.) Oxyethyleneoxypropylene Block Polymer 5. 0 g (Bluronic P-85-trade name-Asahi Denka Kogyo KK) Water 10.0 g Benzyl alcohol 22.0 g Ferriox 115 5.0 g Crystal Violet 0.003 g Powdered silicon dioxide (Aerosil # 380-trade name-3. 5g Nippon Aerosil Co., Ltd.

Example 5 An offset printing plate was prepared in the same manner as in Example 4 except that the following correction liquid was used. When this was printed by an offset printing machine, it was possible to obtain a very good printed matter without stains on the corrected portion as well as stains on the peripheral portion to which the correction liquid was adhered, as in Example 4.

Correction Liquid (5) 4-Butyllactone 50.0 g 6-Hexanolactone 15.0 g Hydroxypropylmethylcellulose (Metroses 1.5 g 65SH50-trade name-Shin-Etsu Chemical Co., Ltd.) Oxyethyleneoxypropylene block polymer 5. 0 g (Bluronic P-85-trade name-Asahi Denka Kogyo KK) Water 10.0 g Benzyl alcohol 10.0 g Ferriox 115 5.0 g Crystal violet 0.003 g Powdered silicon dioxide (Aerosil # 380-trade name-3. 5g Nippon Aerosil Co., Ltd.

Example 6 1.0 g of a trisazo compound represented by the following formula 1 and an oxazole compound represented by the following formula 2 on an aluminum plate obtained by eluting the photosensitive layer of PS plate FNN manufactured by Fuji Photo Film Co., Ltd. with methyl ethyl ketone 2.5 g, benzyl methacrylate and methacrylic acid (methacrylic acid 35 mol%) 1
0.0 g, 60 g of tetrahydrofuran, and 40 g of cyclohexanone were put in a 500 ml glass container together with glass beads and dispersed with a paint shaker (Toyo Seiki Seisakusho Co., Ltd.) for 60 minutes to prepare a photoconductive layer dispersion liquid. This photoconductive layer coating liquid was applied onto the substrate with a bar coater and dried at 100 ° C. for 10 minutes to prepare an electrophotographic printing plate precursor having a dry film thickness of 4 μm. The printing plate thus prepared was charged to a surface potential of +300 V by corona charging, and then a printing plate was prepared by a series of steps such as drawing an image area with a semiconductor laser, toner development, fixing, etching, washing with water, gumming, etc. .

[0041]

[Chemical 1]

[0042]

[Chemical 2]

As a toner, 5 g of polymethylmethacrylate particles (particle size: 0.3 μm) are dispersed as toner particles in 1000 ml of Isobar H (Esso Standard Co., Ltd.), and zirconium naphthenate is used as a charge control agent in an amount of 0.
By adding and using 01 g of the bias voltage of +200 V to the counter electrode, a clear positive toner image could be obtained. Further, 35 g of potassium silicate, 15 g of potassium hydroxide and 10 g of monoethanolamine were diluted in 690 ml of water in the etching part, water in the washing part, and gum solution GU- manufactured by Fuji Photo Film Co., Ltd. in the gum coater part. A solution of 7 diluted 1: 1 with water was used.

A correction solution having the following composition was applied to a part of this image with a brush, and after 10 seconds, it was washed with water and gummed. When this was printed by an offset printing machine, it was possible to obtain a very good printed matter without stains on the corrected portion as well as stains on the peripheral portion to which the correction liquid was attached. Correction liquid (6) Monoethanolamine 25.0 g Hydroxypropyl methylcellulose (Metroze 1.5 g 65SH50-Product name-Shin-Etsu Chemical Co., Ltd.) Oxyethyleneoxypropylene block polymer 5.0 g (Bluronic P-85-Product name-Asahi Denka Co., Ltd.) Industrial Co., Ltd. Water 10.0 g Benzyl alcohol 25.0 g Ferriox 115 5.0 g Crystal Violet 0.003 g Powdered silicon dioxide (Aerosil # 380-Brand name-6.0 g Nippon Aerosil Co., Ltd.)

Examples 7 and 8 An offset printing plate was prepared in the same manner except that the following correction liquid was used instead of the correction liquid of Example 6. When this was printed by an offset printing machine, it was possible to obtain a very good printed matter without stains on the corrected portion as well as stains on the peripheral portion to which the correction liquid was adhered, as in Example 6.

Correction Solution (7) A correction solution was prepared in the same manner except that dimethylaminoethanol was used in place of the monoethanolamine of the correction solution (6).

Correction Solution (8) A correction solution was prepared in the same manner except that phenethyl alcohol was used instead of benzyl alcohol in the correction solution (6).

Example 9 An offset printing plate was prepared in the same manner as in Example 6 except that the following correction liquid was used. When this was printed by an offset printing machine, it was possible to obtain a very good printed matter without stains on the corrected portion as well as stains on the peripheral portion to which the correction liquid was adhered, as in Example 6.

Correction Solution (9) A correction solution was prepared in exactly the same manner except that 10 g of methyl cellosolve was further added to the correction solution (6).

[0050]

INDUSTRIAL APPLICABILITY As described above, in the electrophotographic plate making, when a part of the image portion of the printing plate is modified, the photoconductive layer is dissolved or swelled in addition to at least the organic solvent swelling or dissolving the toner. By using a correction agent containing an organic solvent and / or an alkaline compound, water if necessary, and a thickener, the insoluble portion can be corrected quickly and reliably.

Claims (3)

[Claims] 1. At least one selected from the group consisting of (1) an organic solvent that swells or dissolves a toner, (2) an organic solvent that dissolves or swells a photoconductive layer, and an alkaline compound. A correction agent for electrophotographic lithographic printing plates. 2. The electrophotographic lithographic printing plate correction agent according to claim 1, further comprising water, a thickener, a surfactant and / or a colorant. 3. An electrophotographic lithographic printing plate precursor having a photoconductive layer provided on a conductive substrate, at least a step of forming a toner image, a step of fixing the toner image, and a step of removing the photoconductive layer other than the toner image. When a part of the image area of the lithographic printing plate obtained by the step including the step (a) is modified with a modifying agent, the modifying agent dissolves (1) at least an organic solvent capable of swelling or dissolving the toner and (2) a photoconductive layer. Alternatively, a method for correcting electrophotographic lithographic printing plate comprising at least one selected from the group consisting of a swelling organic solvent and an alkaline compound.