JPH0416952A - Reversal development method with electrophotographic liquid - Google Patents

Abstract

PURPOSE:To obtain the a planographic printing plate which obviates the generation of stains in side face parts by developing an original plate for printing by a developing device which is equal to or below the width of the conductor part of the developing electrode of the device with respect to the width of the original plate for printing in the progressing direction under development. CONSTITUTION:The bias voltage impressed to the side face parts 27 decreases if the width size of the conductive part 14a of the developing electrode of the developing device is set equal to or small within the range of not hindering the formation of the desired adequate image in the case of execution of the reversal development of the original plate for electrophotographic planographic printing by the reversal developing device with the electrophotographic liquid. The sticking of the toner 24 to the original plate is, therefore, extremely lessened. The printed matter free from the staining with ink in the side face parts of the printing plate is obtd. in this way.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to an electrophotographic liquid reversal development method that can prevent toner from adhering to the side surface of an electrophotographic lithographic printing original plate in electrophotographic liquid reversal development.

[Prior art and its problems]

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 original plate with a rough image. on the other hand,
Thanks to advances in computer image processing, large-capacity data storage, and data communication technology, in recent years, everything from inputting, correcting, editing, and page layout to page layout can now be controlled by computers, and high-speed communications networks and satellite communications have enabled instant delivery to remote locations. Electronic editing systems that can output to terminal plotters have been put into practical use. In particular, in the field of newspaper printing, which requires immediacy, not only electronic editing systems but also plate-making systems that can directly obtain printing plates from data are being put into practical use. Currently, among such plate-making systems, a system using an electrophotographic process and exposure using a laser light source (semiconductor laser, He-Ne laser, etc.) is considered promising from various aspects. The main plate-making processes in these systems include charging, exposing, developing, fixing, elution, and
The printing plate is made into a printing plate after washing with water, rinsing, gumming, etc. As a method for manufacturing such a printing original plate, generally, a sheet-like or coil-like aluminum plate is coated with, for example,
Various surface treatments such as graining, anodic oxidation, and chemical treatments are performed alone or in appropriate combinations, and then an electrophotographic photosensitive layer is applied, dried, and then cut into a desired size. When printing such an original plate for electrophotographic printing using a printing plate obtained by image exposure and the above-mentioned processing, especially electrophotographic liquid reversal development processing, printing is performed using a normal sheet-fed printing machine. There is no problem when printing on paper smaller than the size of the printing plate, where the side surface of the printing plate does not become the printing surface. When printing continuously on paper, the side surfaces of the printing plate also enter the paper surface, and the toner electrodeposited on the side surfaces during development is ink receptive, so the ink deposited on the side surfaces of the printing plate is is printed on paper and becomes a stain, resulting in a significant loss of commercial value of the printed material. In electrophotographic reversal development, toner is developed on the side surface of the printing original plate because the conductive support is exposed on the side surface due to cutting, and it does not have the ability to hold potential even if it is charged in the charging process. This is because there is no force on the side surface to repel the toner during reversal development, and the bias voltage applied from the developing electrode protruding above the side surface member to hold the electrode induces toner to adhere to the side surface. It is.

[Purpose of the invention]

An object of the present invention is to provide a developing method and an apparatus for the same, which can produce a lithographic printing plate that does not cause stains on the side surfaces even when electrophotographic liquid reversal development processing is performed.

[Means to solve the problem]

As a result of various studies, the present inventors have found that a potential retaining layer capable of retaining potential due to corona charging is provided on the side surface of an electrophotographic printing original plate having at least a conductive substrate and an electrophotographic photosensitive layer. A method of developing a printed printing plate by electrophotographic liquid reversal development processing, in which the width of the conductive portion of the developing electrode of the device is the same as or smaller than the width of the plate to be developed. It has been found that the above objectives are achieved. I will explain in more detail. In electrophotographic liquid reversal development, in order to properly form images, especially in solid areas, it is common to perform electrode development in which a bias voltage of the same polarity as that of the toner used is applied. However, when an original plate for electrophotographic lithography is developed using a conductive electrode with a width larger than the width of the plate, a bias voltage is also applied to the side surface, and the support is exposed on the side surface. Since it has no potential, toner adheres to it. Therefore, it is possible to prevent toner from adhering to the side surfaces by using an electrophotographic original plate whose side surfaces are coated with an insulating resin that can be dissolved in the eluate, as described in Japanese Patent Application Laid-Open No. 178240/1983. However, depending on the various plate-making systems, the bias voltage value that will be applied to the side surface portions may differ, and the amount of insulating resin applied to the side surface portions must be considered accordingly. Furthermore, when a high bias voltage is applied, the thickness of the resin layer will inevitably increase.
There is a concern about poor elution in the elution step, that is, the occurrence of ink stains due to the fact that the above-mentioned resins are often lipophilic. Therefore, the width size of the conductor portion of the developing electrode of the developing device used in the present invention is set to be equal to the width size (1a) of the electrophotographic printing original plate used for development, as shown in FIG. 1, or as shown in FIG. By making it as small as possible without interfering with proper image formation (usually to a few centimeters from the side edge of the original printing plate), the bias voltage applied to the side surface is drastically reduced, which reduces toner adhesion. However, as shown in FIG. If the printing original plate provided with the layer 23) is uniformly charged and a developing device having a developing electrode 25 is used, the toner is repelled by the potential of the side surface, and toner adhesion to the side surface can be prevented. The material for the conductor portion of the developing electrode used in the present invention is preferably metal from the viewpoint of strength and durability, such as stainless steels, corrosion-resistant Ni alloys, copper and its alloys,
Examples include aluminum and its alloys. Further, the developing electrode used in the present invention is an insulator except for the conductive portion, and requires a certain degree of strength, and since a liquid developer is used, solvent resistance is required. Suitable plastics include: high-density polyethylene, polypropylene, methylpentene resin, polycarbonate, rigid vinyl chloride resin, methacrylic resin, polystyrene, styrene-acrylonitrile copolymer, ABS resin, acetal resin, nylon 66, silicone resin, fluorine resin. Resins, etc., ceramics; for example, high/low pressure porcelain glass, zircon porcelain, alumina porcelain, mullite porcelain, cordierite base, lithium base, steatite, natural talc, forsterite base, rutile base, etc. Rubbers 1 For example, Examples include ebonite, butyl rubber, neoprene, silicone rubber, glass, resin-impregnated wood, and paper. Furthermore, the materials of the developing device other than the electrode plates may be electrically insulating materials such as those described above. The potential retention ability of the potential retention layer that may be provided in the electrophotographic printing original plate used in the present invention includes charging conditions,
Although it varies depending on the exposure conditions, elution conditions, surface potential retention ability of the printing original plate, electrical and chemical properties of the toner used, image content in plate making, etc., it is sufficient if the voltage is below the applied bias voltage. To form the above-described potential-holding layer, prepare a coating solution for forming a potential-holding layer by dissolving the alkali-soluble resin shown below in the soluble solvent shown below, and apply the electrophotographic lithographic plate as described later. It is necessary to apply it to the original printing plate and dry it. Alkali-soluble resins used in the potential holding layer include:
For example, styrene-maleic anhydride copolymer, maleic ester resin, vinyl acetate-maleic anhydride copolymer, phenol resin, styrene-butyl acrylate-acrylic acid copolymer, butyl metharylate-butyl acrylate-methacrylic Examples include acid copolymers, 2-ethylhexyl acrylate-methacrylic acid copolymers, styrene maleic anhydride half ester copolymers, vinyl acetate-crotonic acid copolymers, and the like. Of course, these may be used alone or in combination of two or more. Furthermore, as with the photoconductive layer, a plasticizer, surfactant, or other additives may be added to the potential-retaining layer-forming coating liquid prepared using these resins, if necessary. Furthermore, it is also possible to contain dyes, pigments, etc. to improve recognition. Examples of solvents for the coating solution include halogenated hydrocarbons such as dichloromethane, dichloroethane, and chloroform, alcohols such as methanol, ethanol, 2-propanol, and 1-butanol, and ketones such as acetone, 2-butanone, and cyclohexanone. , glycol ethers such as ethylene glycol monomethyl ether and 2-methoxyethyl acetate, cyclic ethyls such as oxolane, oxane and dioxane, and esters such as ethyl acetate, propyl acetate and butyl acetate. As a method for installing the potential-holding layer, a potential-holding layer-forming coating liquid is applied to the side surface of the above-mentioned electrophotographic printing original plate and dried so as to have an appropriate film thickness after drying. Application methods include, for example, application with a brush, application with a roller,
Examples include application with a sponge, application with a nonwoven fabric, and spray application. Further, the coating can be performed in a state where a large number of electrophotographic printing plate precursors (for example, 1000 plates) are stacked, or one by one. Alternatively, the resin or the like may be formed into a film of appropriate thickness in advance, and the film may be attached to the side surface. As mentioned above, the appropriate film thickness in these cases is the film thickness that can maintain a potential within the range of the bias voltage applied during development when the printing original plate obtained is charged during the plate-making process. It is. In addition, an intermediate layer containing a water-soluble resin or a hydrophilic compound such as an amino acid is added between the potential holding layer and the side surface portion for the purpose of further improving printing stain resistance or improving the elution property in the elution process. It may be provided. The electrophotographic printing original plate used in the present invention has at least one photoconductive layer on a conductive substrate. The conductive substrate may be a plastic sheet or paper having a conductive surface, or aluminum. A metal plate such as a plate or a zinc plate is used, and its thickness is 0.1 to 3 mm.
is preferable, and particularly preferably 0.1 to 0.5 mm. Among these substrates, an aluminum plate having an anodic oxide film is suitable. The aluminum plate used in the present invention is a plate-shaped body made of pure aluminum whose main component is aluminum or an aluminum alloy containing a trace amount of foreign atoms. This foreign atom is
Silicon, iron, manganese, nickel, copper, magnesium, chromium, zinc, bismuth, titanium, etc. The alloy composition has a content of at most 10% by weight or less. Aluminum suitable for the present invention is pure aluminum, but since completely pure aluminum is difficult to produce due to refining technology, it is preferable to use aluminum with as low a content of foreign atoms as possible. As described above, the composition of the aluminum plate applied to the present invention is not limited; conventionally known and publicly used materials can be used as appropriate. In order to remove rolling oil from the surface of the aluminum plate prior to the graining treatment, degreasing treatment using a surfactant or alkaline aqueous solution can be performed if desired. The aluminum plate described above is then subjected to a graining process. Graining 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, a known method called a ball polishing method, a brush polishing method, a blast polishing method, or a bulk polishing method 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 that combines both methods can also be used, as disclosed in Japanese Patent Laid-Open Publication No. 54-63902. The aluminum plate thus roughened is subjected to alkali etching treatment and neutralization treatment as necessary. The aluminum plate thus treated is subsequently 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 concentration of these electrolytes is determined as appropriate depending on the type of electrolyte. The processing conditions for anodic oxidation vary depending on the electrolyte used, so it cannot be stated further, but - the electrolyte concentration between the shells is a solution of 1 to 80% by weight, the liquid temperature is 5 to 70°C, the current density is 5 to 60 A/drrf, It is appropriate if the voltage is in the range of 1 to 100v and the electrolysis time is in the range of 10 to 3000 seconds. The amount of anodic oxide film is preferably about 0.61 to Log/rrf, and more preferably 1 to 6 g/rrf. A conventionally known electrophotographic photosensitive layer is provided on the conductive substrate thus obtained. As the photoconductive material used in the electrophotographic photosensitive layer, many conventionally known inorganic or organic compounds can be used. for example,
Inorganic photoconductive materials include selenium and selenium alloys, amorphous silicon, Cd, CdSe, Cd5Se
, ZnO1ZnS, etc. In addition, organic photoconductive materials include a) triazole derivatives described in US Pat. No. 3,112,197, etc., b) oxadiazole derivatives described in US Pat. No. 3,189,447, etc., and C) Japanese Patent Publication No. 1983- Imidazole derivatives described in US Pat. No. 16096, etc., d) US Pat. No. 3,542,544, US Pat.
No. 51-10983, JP-A No. 5193224, No. 5
No. 5-108667, No. 55-156953, No. 56
= polyaryl alkane derivatives described in US Pat. No. 36656, e) U.S. Pat.
Specification No. 46, JP-A-55-88064, JP-A No. 55-8
No. 8065, No. 49-105537, No. 55-510
86, No. 56-80051, No. 56-88141, No. 57-45545, No. 54-112637, No. 55-74546, etc., f) U.S. Patent No. 3615404 Specification, Special Publication No. 1971-
No. 10105, No. 46-3712, No. 47-2833
No. 6, JP-A-54-83435, JP-A No. 54-11083
6, No. 54-119925, etc., g) U.S. Pat. No. 3,567,450,
No. 3180703, No. 3240597, No. 3658
No. 520, No. 4232103, No. 4175961,
Specification No. 4012376, West German Patent (DAS) 11
No. 10518, Special Publication No. 49-35702, No. 39-2
No. 7577, JP-A-55-144250, JP-A No. 56-1
Arylamine derivatives described in No. 19132, No. 56-22437, h) U.S. Patent No. 352650'1
i) N as described in US Pat. No. 3,542,546, etc.;
N-bicalbasil derivatives, j) Oxazole derivatives described in US Pat. No. 3,257,203, etc., k) Styryl anthracene derivatives, described in JP-A-56-46234, etc., l) JP-A-54-110837, etc. Fluorenone derivatives described in m) U.S. Pat.
No. 59143 (corresponding to U.S. Pat. No. 4,150,987),
No. 55-52063, No. 55-52064, No. 55
-46760, 55-85495, 57-11
No. 350, No. 57-148749, No. 57-1041
Hydrazone derivatives described in US Pat. No. 44, etc., n) US Pat. No. 4,047,948, US Pat.
Benzidine derivatives described in JP-A-58-190953 and JP-A-59-95540, etc.
No. 59-97148, No. 59-195658,
Stilbene derivatives described in Publication No. 62-36674, etc., p) Japanese Patent Publication No. 1973-. Polyvinylcarbazole and its derivatives described in Japanese Patent Publication No. 10966, q) Japanese Patent Publication No. 18674/1986, Japanese Patent Publication No. 43-19192
Vinyl polymers such as polyvinylpyrene, polyvinylanthracene, poly-2-vinyl-4-(4'-dimethylaminophenyl)-5-phenyloxazole, and poly-3-vinyl-N-ethylcarbazole, which are described in the above publication, r ) Polymers such as polyacenaphthylene, polyindene, acenaphthylene/styrene copolymer, etc. described in Japanese Patent Publication No. 19193/1983; S) Pyrene/ as described in Japanese Patent Publication No. 13940/1983
Formaldehyde resin, condensation resin such as ethyl carbazole/formaldehyde resin, t) JP-A-56-90883
U.S. Patent No. 3.397086, U.S. Patent No. 4666802
No., JP-A-51-90827, JP-A No. 52-65564
Examples include metal-free or metal (oxide) phthalocyanine and naphthalocyanine, and derivatives thereof, as described in Japanese Patent Publication No. 3, JP-A-61-2061, and JP-A-644389. The organic photoconductive compounds according to the present invention include a) to U).
The present invention is not limited to the compounds listed above, and conventionally known organic photoconductive compounds can be used. Two or more types of these organic photoconductive compounds can be used in combination, if desired. Furthermore, various pigments, dyes, etc. can be used in combination for the purpose of improving the sensitivity of the photoconductor or imparting sensitivity to a desired wavelength range. Examples of these include: 1) U.S. Pat. No. 4,436,800, U.S. Pat.
No. 41, No. 58-192042, No. 58-21926
No. 3, No. 59-78356, No. 60-179746, No. 61-148453, No. 61-238063,
Monoazo, bisazo, trisazo pigments described in Japanese Patent Publications No. 60-5941, No. 60-45664, etc.; 2) Metal phthalocyanine or metal-free phthalocyanine described in U.S. Pat. No. 3,397,086, No. 4,666,802, etc. Phthalocyanine pigment, 3) U.S. Patent No. 33
4) Indigo and thioindigo derivatives described in British Patent No. 2237680, etc.; 5) Quinacridone pigments described in British Patent No. 2237679, etc.; 6) British Patent No. 2237679, etc.; Patent No. 2237678, JP-A-59-
7) Bisbenzimidazole pigments described in JP-A-47-30331, etc.; 8) U.S. Pat. Nos. 4,396,610 and 4,644,082. Squarium ring-based pigments described in specifications, etc., 9) JP-A-1989-1999
Azurenium salt pigments described in Publications No. 9-53850 and No. 61-212542. In addition, as a sensitization fee, "electronic photography" 129 (1
973), “Organic Synthetic Chemistry” 24 No. 11 1010
(1966) and the like can be used. Examples include: 10) U.S. Patent Nos. 3,141,770 and 4,283,475
specification, Japanese Patent Publication No. 48-25658, Japanese Patent Publication No. 61-7
Pyrylium dye described in 1965 publication etc., 11) Applie+I Optics Suppll
ement 3 '50 (1969), Japanese Patent Application Publication No. 1987-
12) Cyanine dyes described in U.S. Pat. No. 3,597,196, etc.; 13) JP-A-59-1'6'4588, No. 60-16
These include styryl dyes described in No. 3047, No. 60-252517, and the like. These sensitizing dyes may be used alone or in combination of two or more. The photoconductive layer according to the present invention contains compounds such as trinitrofluorenone, chloranil, and tetracyanoethylene in order to improve sensitivity and the like.
No. 2239, No. 58-129439, No. 60-719
Compounds described in Publication No. 65 and the like can be used in combination. In photoreceptors for electrophotographic printing plates, the photoconductive compound itself may have film properties, but if the photoconductive compound alone does not have film properties, a binder resin may be used in combination. I can do it. In the electrophotographic photoconductive layer according to the present invention, it is necessary to finally remove the non-image area photoconductive layer, but this step depends on the solubility of the photoconductive layer to the eluent and the resistivity of the toner image to the eluate. determined by the relative relationship of
- Although it cannot be expressed generally, at least as a binder resin,
A polymer compound that is soluble or dispersible in the above-mentioned eluent is preferred. Specific examples include styrene/maleic anhydride copolymer,
Styrene/maleic acid monoester copolymer, methacrylic acid/methacrylic acid ester copolymer, styrene/'methacrylic acid/methacrylic acid ester copolymer, acrylic acid/methacrylic acid ester copolymer, styrene/'acrylic acid/methacrylic acid ester copolymer Acid ester copolymer, vinyl acetate/
Styrene such as crotonic acid copolymer, vinyl acetate/crotonic acid/methacrylic acid ester copolymer, methacrylic ester, acrylic ester, vinyl acetate, vinyl benzoate, etc. and acrylic acid, methacrylic acid, itaconic acid, crotonic acid, Copolymers with carboxylic acid-containing monomers such as maleic acid, maleic anhydride, and fumaric acid or acid anhydride group-containing monomers, methacrylic acid amide, vinylpyrrolidone, phenolic hydroxyl groups, sulfonic acid groups, sulfonamide groups,
Examples include copolymers containing monomers having sulfonimide groups, phenol resins, partially saponified vinyl acetate resins, xylene resins, and vinyl acetal resins such as polyvinyl butyral. Copolymers containing monomers having acid anhydride groups or carboxylic acid groups and phenol resins have high charge retention ability when used as photoreceptors for electrophotographic printing plates, and therefore can be advantageously used. As the monomer-containing copolymer having an acid anhydride group, a copolymer of styrene and maleic anhydride is preferred. Examples of copolymers containing monomers having carboxylic acid groups include copolymers of styrene and maleic acid monoester, and copolymers of two or more of acrylic acid or methacrylic acid and their alkyl esters, aryl esters, or aralkyl esters. Combination is preferred. A copolymer of vinyl acetate and crotonic acid is also good. Among the phenol resins, particularly preferred are novolac resins obtained by condensing phenol, 0-cresol, m-cresol, or p-cresol with methanal or ethanal under acidic conditions. The binder resin may be used alone or in combination of two or more types. When using a photoconductive compound and a binder resin, if the content of the photoconductive compound is small, the sensitivity will be low. It is preferable to use a mixture of 15 parts by weight or more. In addition, if the photoconductive layer is thin, the charge necessary for toner development cannot be charged, and if it is thick, it not only accelerates the deterioration of the eluate but also induces side etching during elution, making it difficult to obtain a good image. Therefore, it is preferably 0.10 to 30 μm, more preferably 0.50 to 10 μm. The electrophotographic lithographic printing plate according to the present invention is obtained by coating a photoconductive layer on a conductive support according to a conventional method. In producing the photoconductive layer, the components constituting the photoconductive layer may be contained in the same layer, or separately contained in two or more layers, for example, a charge carrier generating substance and a charge carrier transporting substance may be contained. Methods of separating and using different layers are known,
It can be created using any method. 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, it can be prepared using a ball mill, paint shaker, dyno mill, attritor, etc. It is used after being dispersed to an average particle size of 0.01 to 5 μm using a dispersing machine. The binder resin and other additives used in the photoconductive layer can be added during or after dispersing the pigment. The coating solution prepared in this manner is coated onto a support by a known method such as spin coating, blade coating, knife coating, reverse roll coating, dip coating, rod bar coating, or spray coating and is dried to form an electrophotographic printing plate. can be obtained. Solvents for the coating solution include halogenated hydrocarbons such as dichloromethane, dichloroethane, and chloroform, alcohols such as methanol, ethanol, 2-propanol, and 1-butanol, ketones such as acetone, 2-butanone, and cyclohexanone, and ethylene. Examples include glycol ethers such as glycol monomethyl ether and 2-methoxyethyl acetate, cyclic ethers such as oxolane, oxane, and dioxane, and esters such as ethyl acetate, propyl acetate, and butyl acetate. In addition to the photoconductive compound and the binder resin, plasticizers, surfactants, and other additives may be added to the photoconductive layer as necessary to improve the physical properties of the photoconductive layer, such as its flexibility and coating surface condition. You can add things. 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. Casein, polyvinyl alcohol, ethyl cellulose, phenol resin, styrene/maleic anhydride copolymer, maleic acid, etc. may be added between the conductive support and the photoconductive layer as necessary to improve adhesion and electrophotographic properties. acid/acrylic acid copolymers, acrylic acid/methacrylic acid copolymers, polyacrylic acid, polymaleic acid, poly-α-hydroxyacrylic acid, polyitaconic acid, and alkali metal and/or ammonium salts of these polymer electrolytes, Amino alcohols such as ethanolamine and ethylenediamine,
Amines such as propanediamine and triethylenetetramine, organic ammonium salts such as their hydrochlorides, phosphates, and oxalates, phosphoric acid esters and their salts such as inozite hexaphosphate, malic acid, citric acid, and hydroxycarboxylic acids such as tartaric acid, and salts thereof, monoaminocarboxylic acids such as glycine and alanine, oxyamino acids such as serine, threonine, and dihydroxyethylglycine, S-containing amino acids such as cysteine and cystine, aspartic acid, Monoamino dicarboxylic acids such as glutamic acid, diamino monocarboxylic acids such as lysine, aromatic amino acids such as p-hydroxyphenylglycine, phenylalanin, anthranilic acid, amino acids with heterocycles such as tryptophan and proline, sulfamic acid, cyclo Aliphatic aminosulfonic acids such as xylsulfamic acid, ethylenediaminetetraacetic acid, nitrilotriacetic acid, iminodiacetic acid, hydroxyethylethylenediaminetriacetic acid, di(
(Poly)aminopolyacetic acid such as hydroxyethyl)ethylenediaminediacetic acid, ethylenediaminediacetic acid, diethylenetriaminepentaacetic acid, triethylenetetraminehexaacetic acid, aminotri(methylenephosphonic) acid, 1-hydroxyethylidene-1,1-diphosphonic acid, ethylenediaminetetra (poly)aminopoly(methylenephosphonic acid) such as (methylenephosphonic acid), hexamethylenediaminetetra (methylenephosphonic acid), diethylenetriaminepenta(methylenephosphonic acid), and their analogues, and at least a portion of the acid groups of these compounds. An intermediate layer made of an alkali metal salt, an ammonium salt, or the like may be provided. The electrophotographic lithographic printing plate used in the present invention can be produced by known operations using the aforementioned electrophotographic printing original plate. That is, it is charged substantially uniformly in a dark place, and an electrostatic latent image is formed by imagewise exposure. Exposure methods include reflective image exposure using a xenon lamp, tungsten lamp, fluorescent lamp, etc. as a light source, contact exposure through a transparent positive film, and scanning exposure using a laser beam, a light emitting diode, etc. When performing scanning exposure, He-Ne
Laser, He-Cd laser, argon ion laser, krypton ion laser, ruby laser, YAG
Laser, nitrogen laser, dye laser, excimer laser, GaAs/GaAlAs, InG
Scanning exposure using a laser light source such as a semiconductor laser such as aAsP, alexandrite laser, or copper vapor laser, or scanning exposure using a light emitting diode or liquid crystal shutter (line printer type using a light emitting diode array, liquid crystal shutter array, etc.) light source (including books). Next, the electrostatic latent image is developed by the liquid reversal development method of the present invention, which is suitable for forming a fine image and creating a printing plate with good reproducibility. The range of the bias voltage to be applied cannot be specified because it varies depending on the surface potential of the non-image area of the printing master plate and the electrical properties of the toner used, but it is usually from 5V to several 100V, and it is within this range. It is preferable if there is one. In the case of reversal development, as long as the polarity of the toner used is the same as the polarity with which the original printing plate used is charged, and the polarity of the applied bias voltage is also the same, either 10 or - can be used without problems. . The toner image can be fixed by known fixing methods, such as heat fixing, pressure fixing, and the like. Using the toner image thus formed as a resist, the photoconductive layer in the non-image area and the potential holding layer on the side surfaces that prevented adhesion of toner are removed with an eluent, and a printing plate can be prepared by processing such as gumming. The toner according to the present invention needs to contain a resin component that has resistivity to the eluate described later. Examples of resin components include acrylic resins consisting of methacrylic acid and methacrylic esters, vinyl acetate resins,
Copolymers of vinyl acetate and ethylene or vinyl chloride, vinyl chloride resins, vinylidene chloride resins, vinyl acetal resins such as polyvinyl butyral, polystyrene, copolymers of styrene and butadiene, methacrylic esters, etc., polyethylene, polypropylene and its chloride,
Polyester resins such as polyethylene terephthalate and polyethylene isophthalate, polyamide resins such as polycapramide and polyhexamethylene aziboamide, phenolic resins, xylene resins, alkyd resins, vinyl-modified alkyd resins, gelatin, cellulose ester derivatives such as carboxymethylcellulose, etc. Examples include wax and wax. Further, the toner may contain a dye or a charge control agent within a range that does not adversely affect development, fixing, etc. The eluent according to the present invention preferably contains an alkaline agent and has a buffering capacity. Conventionally, the alkaline agents used in developing solutions for photosensitive planographic printing plates (28th plate) include:
Silicates expressed by the general formula S i 02 /M20 (M=Na, K), alkali metal hydroxides, phosphoric acid, alkali metal carbonates, inorganic alkaline agents such as ammonium salts, ethanolamines, ethylenediamine, propanediamine organic alkaline agents such as triethylenetetramine, morpholine, etc., and mixtures thereof; however, since the above-mentioned silicate exhibits a particularly strong buffering capacity, the eluate according to the present invention contains at least one silicate. Preferably, it is further added with another alkali agent such as an alkali metal hydroxide. The eluate according to the present invention further includes the ionic compound described in JP-A-55-25100, the water-soluble cationic polymer described in JP-A-55-95946, and the water-soluble cationic polymer described in JP-A-56-142528. Water-soluble amphoteric polymer electrolyte, neutral salt described in JP-A-5875152, chelating agent described in JP-A-58-190952, liquid viscosity modifier described in JP-A-1177541, JP-A-63-226657 Known ingredients such as preservatives and bactericidal agents described in the above publication, various surfactants, natural and synthetic water-soluble polymers, etc. can be included as necessary. The solvent in the eluate is not particularly limited as long as it can stably disperse and dissolve the above components, but water is more preferably used, and ion-exchanged water is advantageously used. In addition, in order to more stably mix and disperse the above components in an amount that does not substantially cause elution in a solution containing the eluate composition excluding the alkaline agent mentioned above, a minimum amount of organic A solvent may also be added.

【Example】

Hereinafter, the present invention will be explained in more detail with reference to Examples. Note that "%" and "parts" indicate weight % and parts by weight, respectively, unless otherwise specified. Example I JIS1050 aluminum sheet at 60°C 110%
Immersed in NaOH aqueous solution, the amount of aluminum dissolved is 6 g
I etched it so that it read /rrf. After washing with water, it was immersed in a 30% nitric acid aqueous solution for 1 minute to neutralize it, and then thoroughly washed with water. Thereafter, electrolytic surface treatment was performed for 20 seconds in a 0.7% nitric acid aqueous solution, and the surface was washed by immersion in a 20% sulfuric acid aqueous solution at 50° C., followed by water washing. Furthermore, a support for a printing plate was prepared by performing anodization treatment in a 20% aqueous sulfuric acid solution, washing with water, and drying. On the surface-treated surface of this support, the following photoconductive layer composition was dispersed in a paint shaker for 1 hour, applied with a vacuum coater, and dried at 90° C. for 5 minutes to prepare an electrophotographic lithographic printing plate. At this time, the coating amount of the photoconductive layer was 4. ．． 5 g/r+ (photoconductive layer coating composition: butyl methacrylate/methacrylic acid copolymer (methacrylic acid 40%) 18 parts fused metal phthalocyanine 4 parts butyl acetate
60 Part 2-Proper Tools
The printing master plate obtained in 18 copies was mixed with a basis weight of 50 g/
Stack 50 sheets of 'rrf paper laminated with 10 μm thick polyethylene on one side so that the polyethylene side of the backing paper is in contact with the photoconductive layer, and use a guillotine cutter to remove 40 sheets.
It was cut into a size of 0mm x 295rrB71, and the following intermediate layer composition was applied to all sides of the cut using a sponge. After drying at room temperature, the coverage is 1g/11? Met. Intermediate layer composition 30% gum arabic aqueous solution 70 parts 85%
Phosphoric acid 5.6 parts Sodium nitrate 1.4 parts Magnesium sulfate
1 part pure water
22 parts The following potential-retaining layer composition was applied with a sponge onto the intermediate layer of the printing original plate that had undergone the above treatment.
The photosensitive layer was coated and dried so that when the surface potential of the photosensitive layer was charged to about 300 V, the potential held at the side surface (holding potential) was 30 V. Potential-holding layer composition Lauryl methacrylate-methacrylic acid copolymer (average molecular weight: 15,000) 10 parts Methanol 90 parts The printing original plate thus prepared was subjected to corona discharge in a dark place to increase the surface potential (VO). After charging to approximately +300V, scanning image exposure was performed using a semiconductor laser (780 parts m), and immediately a positively charged toner (manufactured by Mitsubishi Paper Industries, LOM-EDI) was applied.
T), 295 was added to the developing device having the developing electrode shown below.
Liquid reversal development (developing bias voltage: 90 V) was performed with the mm-wide side portions as the front and rear of the plate, and the toner was thermally fixed to obtain a toner image on the photoconductive layer. Development electrode The development electrode is 294mm x 150m as shown in Figure 3.
Plate stainless steel (SUS30) with a size of mX1mrn
4) was used, which was 335 mm x 150 mm x 10 mm. Duracone (registered trademark of Polyplastics) was used for the plate-like parts other than stainless steel. No toner development was observed on the treated side surface of the printing original plate on which the toner image was formed in this manner. Next, using the automatic elution machine shown below, eluate, washing solution,
A plate-making process was performed using a rinsing liquid and a rinsing liquid. Automatic elution machine elution tank followed by washing tank and rinsing tank (capacity of multiple tanks is 2
0L), a drive device that transports the toner-developed electrophotographic printing plate, a device that circulates the processing liquid in each processing tank in a cycle of storage tank → pump → spray nozzle → storage tank, and each processing An automatic machine with a tank refilling device was used. Eluent composition Sodium silicate aqueous solution (Si03 min 30% by weight, 5j0
2/N820 molar ratio 2.5) 20 parts potassium hydroxide 1 part pure water
79 parts Washing liquid composition Sodium dioctyl sulfosuccinate 0.1 part Pure water
99.9 parts Rinse liquid composition Citric acid 0.8 parts Phosphoric acid (85% aqueous solution) 0.5 parts Decaglyceryl monolaurate 0.05 parts Pure water
100 copies were then gummed using the inter-shell method and then printed on an offset form rotary printing press (
Using printing paper (0W-200ER manufactured by Ukita Kogyo ■),
Diaform 45 made by Mitsubishi Paper Mills, basis weight 52゜3g/
d paper width 470 mm) using a conventional method under the printing conditions shown in FIG. 4, no ink stains corresponding to the sides of the printing plate were observed in the printed matter after 100,000 copies were printed. Comparative Example 1 The plate-shaped part of the developing electrode of the developing device was made entirely of metal (SUS
When the same process as in Example 1 was carried out except that development was performed using 304), toner adhesion was observed on the side surfaces. When this printing plate was printed in the same manner as in Example 1, ink stains corresponding to the side surfaces appeared on the printed matter immediately after printing began. Comparative Example 2 Using the same developing device as in Comparative Example 1, an electrophotographic printing original plate without any layer on the side surface was subjected to the platemaking process in the same manner as in Example 1. Adhesion of toner was observed. When printing was performed using this printing plate in the same manner as in Example 1,
Immediately after printing began, ink stains corresponding to the side surfaces of the printed matter occurred.

【Effect of the invention】

According to the present invention, even when an original plate for electrophotographic lithography is subjected to electrophotographic reversal development processing to produce a printing plate, and printing is performed on a substrate larger than the size of the printing plate, the ink corresponding to the side surface of the printing plate is Printed matter without stains can be obtained.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing a developing electrode of a developing device according to the present invention, with A being a side view and B being a top view. FIG. 2 is a conceptual partial cross-sectional view of a developing device according to the present invention in which development is performed using a developing electrode. FIG. 3 is a schematic partial perspective view of a printing plate according to the present invention being attached to an offset form rotary printing machine and printing is being carried out. FIG. 4 is a diagram showing a developing electrode of a developing device according to the present invention, in which A is a front view, B is a bottom view, and C is a side view. 11... Original plate for electrophotographic lithography (lla; width size) 12... Entrance side squeezing roll 13... Toner rectification chamber 14a... Developing electrode (conductor part) 14b... Developing electrode (insulated) Body part) 15...Lower guide plate 16...Outlet side squeeze roll 21...Support 22...Photoconductive layer 23...Potential holding layer 24...Toner 25a...Developing electrode ( Conductor part) 25b... Developing electrode (insulator part) 26... Bias power supply 27... Side part 31... Toner rectification chamber 32... Toner discharge slit 33... Conductor part 34 ... Insulator section 41 ... Plate cylinder 42 ... Blanket cylinder 43 ... Impression cylinder 44 ... Original plate for electrophotographic printing 45 ... Side part of original plate for electrophotographic printing 46... Plate installation is part 47. Printing paper record 1 11- is the child photolithographic printing original plate (Ila: radius size) 2... Population concern 1 Squeezing roll 3... Toner rectification chamber 4a Developing electrode (conductor part) ) 4b-Developing electrode (insulator part) 5 Lower guide plate 6...Exit side squeezing roll melting glue 21...Support 22...Photoconductive layer 23...Potential holding layer 24,... - Toner 25a...Developing electrode (conductor 8B') 25b...
Developing electrode (insulator! 16) 26...Bias 1! 0 2 7 - Ikai 11 ゐ (F 入 Ｇ D Prison 4 Procedural amendment (voluntary) Case description 1990 Patent Application No. 121748 Name of the invention Electrophotographic liquid reversal developing method 1 Person who corrects the case Relationship with the case Patent applicant...Plate 1lIil...Plunket assembly...Impression cylinder...Original plate for electrophotographic printing...Wound surface B6 of the original plate for electrophotographic printing...1t section of plate removal...Printing Sheet 4, ￥5゜h 廿(600) 248] (1) Page 39 of the specification, lines 5 to 15 are corrected as follows: ``Figure 1 shows the developing device of the present invention. 2 is a schematic diagram showing an electrode, and A is a side view and B is a top view. FIG. 2 is a partial conceptual cross-sectional view of a developing device according to the present invention in which development is performed using a developing electrode.

Claims (1)

[Scope of Claims] 1. In a method of reversing developing an electrophotographic lithographic printing original plate using an electrophotographic liquid reversal developing device, the conductivity of the developing electrode of the device is determined with respect to the width of the printing original plate in the direction of movement during development. An electrophotographic liquid reversal developing method characterized in that development is carried out using a developing device whose body width is equal to or smaller than that. 2. The electrophotographic liquid reversal development method according to claim 1, wherein the printing original plate has a potential holding layer on its side surface that can hold at least a potential due to corona charging.