JPH0611914A - Method and device for fabrication electrophotographic printed plate - Google Patents

Abstract

PURPOSE:To enable photolithography in which line width reproducibility is not fluctuated with the number of printed matters by removing a toner layer at the peripheral edge of an image during a process for removing photoconductive layers other than a toner image and/or subsequent processes. CONSTITUTION:An electrophotographic printing plate 1 to be carried to an etching portion 2 after toner development and fixation is etched by an alkaline solution at the photoconductive layer of its non-image portion other than its toner image-forming portion. An excess of alkaline solution attached to the electrophotographic printing plate 1 is removed by a squeeze portion 3 and then the prate 1 is washed in water at a water wash portion 4. Next, Desensitization is performed by application of a gum liquid to the plate 1 at a gum liquid applying portion 5 and is dried at a drying portion 6. Some solvent, preferably an organic solvent such as methanol and benzyl alcohol may be employed as the liquid for etching the photoconductive insulating layer of the toner non-image portion, and additives such as surface active agents may be added thereto. Such printing processes provide sharp and clear printed matters without causing degrading of reproducibility of image line width.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an electrophotographic lithographic printing plate which forms a printing image by forming a toner image on a photoconductive layer and then removing non-image areas other than the toner image area. Manufacturing equipment

[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. The plate making is carried out by contact exposure of a film original plate on which an image is recorded in advance. 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 operation is consistently performed from manuscript input, correction, editing, layout to page set, 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 original documents are currently stored in the form of a film and printing plates are duplicated as needed based on this, with the development of large-capacity recording media such as optical disks, Will be stored as digital data on these recording media. However, direct type printing plates, which directly produce printing plates from the output of the end plotter, have hardly been put into practical use, and even when the electronic editing system is operating, the output is performed to 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 because it is difficult to develop a direct type printing plate having a high sensitivity for producing a printing plate within a practical time by using a light source of an output plotter (eg, He-Ne laser, semiconductor laser, etc.). It was the cause.

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 the photoconductive layer in the non-image area after forming a toner image is already known. For example, Japanese Examined Patent Publication Nos. 37-17162 and 38-
6961, 38-7758, 41-2426.
No. 46-39405, JP-A-50-19509.
No. 50, No. 50-19510, No. 52-2437, No. 5
4-145538, 54-134632, 55
-105254, 55-153948, 55-
161250, 57-147656 and 57-1.
The printing original plate for electrophotographic plate making described in JP-A-61863 and the like can be mentioned. In the above method, a binder resin that dissolves in an alkaline solvent or that swells and desorbs is used as a binder resin for the electrophotographic photoreceptor, and a toner image is used as a resist,
A lithographic printing plate is obtained by eluting (etching) parts other than the toner image area to expose the hydrophilic surface.

[0004]

However, the printed matter obtained by the lithographic printing plate thus obtained may have ink stains on the non-image areas, resulting in print stains. If the solubility of the etching liquid is improved to remove this stain, the etching proceeds in the horizontal direction of the image area (side etching). When this printing plate is actually printed, ink adheres to the toner portion in the initial stage of printing, but as the printing progresses, the toner layer on the part where the photoconductive layer is eluted due to side etching is peeled off and the image line width becomes narrow. . Therefore, there is a problem in that the reproducibility of the image line width decreases as the printing is performed. In addition, in order to solve this, binding resin,
Attempts have been made to reduce side etching with etching solutions, substrates, etc., but none of them was satisfactory.

The present invention has been made under the circumstances described above, and an object of the present invention is to have a photoconductive layer on a conductive support, and after forming a toner image on the photoconductive layer, a toner is formed. To provide a method and an apparatus for producing a lithographic printing plate which does not vary in line width reproducibility depending on the number of printed sheets in an electrophotographic plate making plate which is a printing plate by removing non-image parts other than image parts. It is in.

[0006]

As a result of intensive studies to solve the above-mentioned drawbacks, the present invention has revealed that at least the step of charging and exposing in an electrophotographic lithographic printing plate precursor having a photoconductive layer provided on a conductive substrate. In a method for producing an electrophotographic lithographic printing plate by a step including a step, a step of developing with a toner, a step of fixing a toner, and a step of removing a photoconductive layer other than a toner image, a photoconductive layer other than a toner image The above object can be achieved by removing the toner layer at the peripheral edge of the image in the step of removing the toner and / or the subsequent step.

[0007]

In the step of etching the photoconductive layer as described above and the subsequent steps, by removing the excess toner layer in the side-etched portion, the reproducibility of the image line width varies with printing. It is possible to prevent and always produce a good printed matter in a stable manner. In the present invention, the side-etched toner layer at the peripheral edge of the image can be removed by mechanical friction or the like during the etching step or in the subsequent steps. The step of removing may be any step as long as it is during and / or after the etching step, but it is preferably removed by a squeeze step, a water washing step, a gum solution applying step or the like so that the removed toner is not scattered in the air. The method of removing the toner layer in the side-etched portion of the present invention can be realized by using a roller-shaped brush, molton, sponge or the like. These rollers are removed by abutting in the direction perpendicular to the conveying direction of the electrophotographic printing plate, but by combining rollers having an appropriate angle or sliding the rollers and abutting them, the toner around the image area can be removed. The layer can be removed uniformly, and the present invention can be carried out more effectively. In addition, an adhesive film may be used as a removing means in the space to adhesively peel off the toner layer in the side-etched portion. It is desirable that a roll-shaped tape is used as the adhesive film and that a new surface is always pressure-bonded. In this case, it can be performed in the space between the steps after the etching step,
The removed toner does not contaminate the surroundings.

[0008]

The present invention will be described in detail with reference to the following examples.
FIG. 1 is a schematic sectional view showing an embodiment of the electrophotographic lithographic printing plate manufacturing method of the present invention. The electrophotographic printing plate 1 on which toner has been developed and fixed is transported to the etching processing section 2 by a transporting means (not shown). Etching processing unit 2
Applies an alkaline solution to the electrophotographic printing plate 1 to etch (elute) the photoconductive layer in the non-image portion (that is, the portion other than the portion where the toner image is formed). Next, a squeeze part 3 for removing the excess alkaline solution adhering to the electrophotographic printing plate 1, a water washing part 4 for washing the squeezed electrophotographic printing plate with water to remove the alkaline solution, and a washed electrophotographic printing plate A gum solution applying section 5 for applying a gum solution for desensitizing and a drying section 6 for drying the electrophotographic printing plate coated with the gum solution are arranged. In addition, each part has an electrophotographic printing plate 1
Conveyance rollers 7, 8, 9, 11, 1 for nipping and conveying
2 and 13 are provided, and these transport rollers are driven by a motor (not shown).

An etching tank 23 is provided in the etching section 2, the electrophotographic printing plate 1 is carried by a carrying roller 8 and immersed in the etching tank by a guide roller 14. Further, the alkaline solution filled in the etching tank 23 is circulated by the circulation pump 15 and the injection nozzle 16
Further, the alkaline solution is ejected onto the electrophotographic printing plate 1. The electrophotographic printing plate 1 having the non-image portion etched is conveyed to the squeeze portion 3 and the squeeze roller 10 removes an excessive alkaline solution. A roller 18 is arranged in close contact with the squeeze roller 10 on the receiving portion side of the squeeze roller 10, and the alkaline solution removed by the squeeze roller 10 is removed via the roller 18. The electrophotographic printing plate 1 from which the alkaline solution has been removed is conveyed to the water washing section 4. A pump 19 for circulating water and a jet nozzle 24 for jetting water to the electrophotographic printing plate are arranged in the water washing section. Further, a roller-shaped brush 22 is arranged and rotated by a motor (not shown) in the direction opposite to the transport direction of the electrophotographic printing plate 1. The brush roller 22 removes the excess toner layer that has been side-etched. Next, the electrophotographic printing plate 1 is conveyed to the gum solution application section 5 in which the circulation pump 20 and the spray nozzle 25 are arranged, is desensitized, and is then dried by the drying section 6 in which the dryer 21 is arranged. The electrophotographic printing plate produced by this apparatus was a printing plate that maintained good image quality even when printing proceeded and did not deteriorate image reproducibility.

As a pre-process of the etching section, a plate feeding section of the photoconductor, a charging section, a scanning exposure section by a laser, a surface exposure section via a silver salt original document, a toner developing section, a fixing section and the like are provided. For the toner development, conventionally known methods, for example, various methods such as cascade development, magnetic brush development, powder cloud development and liquid development can be used. Among them, liquid development is capable of forming a fine image and is suitable for making a printing plate. At this time, either a positive development or a reversal development method is possible depending on the combination of the charge polarity of the photoconductor and the charge polarity of the toner. As a post-process of the main etching unit, if necessary, a process such as a plate inspection unit equipped with a CCD sensor or the like for pattern recognition, a vendor unit, a plate accumulating unit, and the like can be provided.

FIG. 2 is a schematic sectional view showing another embodiment of the present invention. The etching part 2 for etching the photoconductive layer in the non-image part, the squeeze part 3 for removing the alkaline solution, and the drying part 6 are arranged in the same manner as in FIG. 1, but in FIG. 1, the brush is arranged in the water washing part 4. The roller 22 is arranged in the gum solution applying section 5 for applying the gum solution to desensitize the washed electrophotographic printing plate, and is rotated by a motor (not shown) to remove the toner layer at the peripheral edge of the image. It has become. The electrophotographic printing plate thus prepared was a printing plate that maintained good image quality even when printing proceeded and did not change in image reproducibility.

FIG. 3 is a schematic sectional view showing another embodiment of the method for producing an electrophotographic lithographic printing plate according to the present invention. The electrophotographic printing plate 1 on which the toner has been developed and fixed is conveyed to the etching section 2 by a conveying means (not shown). The etching section 2 applies an alkaline solution to the electrophotographic printing plate 1 to etch (elute) the photoconductive layer in the non-image area (that is, the area other than the area where the toner image is formed). Next, the excess alkaline solution adhering to the electrophotographic printing plate 1 is squeezed off, the squeezed electrophotographic printing plate is washed with water to remove the alkaline solution, and a water-washed electrophotographic printing plate is desensitized. A gum solution application unit 5 for applying a gum solution is provided for the purpose of converting the gum solution. Conveying rollers 27, 28, 30, 31, 3 for nipping and conveying the electrophotographic printing plate 1 in each section.
2 and 33 are provided, and these transport rollers are driven by a motor (not shown).

An etching tank 23 is provided in the etching section, and the electrophotographic printing plate 1 is conveyed by a conveying roller 27 and guided by a guide roller 34. Further, the alkaline solution filled in the etching solution tank 37 is circulated by the circulation pump 35, and the alkaline solution is jetted from the jet nozzle 36 onto the electrophotographic printing plate. Etching part 2
A brush roller 40 is disposed in the sheet feeding roller, and is rotated in a direction opposite to the conveying direction of the electrophotographic printing plate 1 by a motor (not shown). The brush roller 40 removes the side-etched toner layer. The electrophotographic printing plate having the non-image area etched is conveyed by the squeeze roller 29 to remove the alkaline solution. The electrophotographic printing plate 1 from which the alkaline solution has been removed is conveyed to the water washing section 4. A circulation pump 41 for circulating water and a jet nozzle 42 for jetting water to the electrophotographic printing plate are arranged in the water washing section. next,
The electrophotographic printing plate 1 is conveyed to the gum solution application section 5 in which the circulation pump 43 and the spray nozzle 44 are arranged, and is desensitized and then dried. The electrophotographic printing plate produced by this apparatus was a printing plate that maintained good image quality even when printing proceeded and did not deteriorate image reproducibility.

FIG. 4 is a schematic sectional view showing another embodiment of the present invention. This figure shows the same arrangement as that of FIG. 3 except that the brush roller 40 arranged in the etching section 2 in FIG. 3 is arranged in the water washing section 4. The brush roller 40 arranged in the washing section is rotated and slid by a motor (not shown) to remove the toner layer at the peripheral edge of the image. The electrophotographic printing plate thus prepared was a printing plate that maintained good image quality even when printing proceeded and did not deteriorate image reproduction.

FIG. 5 is a schematic sectional view showing another embodiment of the present invention. In FIG. 3, the brush roller 40 arranged in the etching section 2 in FIG. 3 is arranged in the gum solution applying section 5 for applying the gum solution. The brush roller 40 arranged in the gum solution application section 5 is rotated and slid by a motor (not shown) to remove the toner layer at the peripheral edge of the image. The electrophotographic printing plate thus prepared was a printing plate that maintained good image quality even when printing proceeded and did not deteriorate image reproducibility.

As yet another embodiment, FIG. 6 shows an example of removing the toner layer in the side-etched portion using an adhesive film. In the figure, a water washing / drying unit 45 and a toner removing unit 46 are provided between the steps of the water washing unit 4 and the gum solution applying unit 5 after etching. The electrophotographic printing plate 1 sent by the conveyance roller 11 of the washing section 4 is washed by the washing and drying section 4
It is dried by the dryer 21 of No. 5 and sent to the toner removing section 46 through the carrying roller 13. The dried electrophotographic printing plate 1 is pressure-bonded to the pressure-sensitive adhesive film by the pressure-sensitive adhesive roller 47 and the receiving roller 48 in the toner removing section 46, and the excess toner layer is peeled off and sent to the gum solution application section. Here, if a roll-shaped adhesive film is used, it is supplied along the circumferential surface of the adhesive roll, and after being pressed onto the plate surface and wound on a reel, a new surface can always be used.

Next, the structure of the electrophotographic printing original plate which can use the apparatus of the present invention will be described. As the conductive substrate of the electrophotographic printing original plate used in the present invention, various supports can be used. For example, a plastic sheet with an electrically conductive surface or a paper, especially solvent-impervious and electrically conductive, an aluminum plate, a zinc plate, or a copper-
Bimetal plate such as aluminum plate, copper-stainless steel plate, chrome-copper plate, or trimetal plate such as chrome-copper-aluminum plate, chrome-lead-iron plate, chrome-copper-stainless plate, etc. A substrate is used, and its thickness is preferably 0.1 to 3 mm, and particularly preferably 0.
1 to 0.5 mm is preferable. Among these substrates, the aluminum plate is preferably used. The aluminum plate used in the present invention 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. Can be used. This aluminum plate can be used after graining and anodizing by a conventionally known method. Furthermore, Japanese Examined Japanese Patent Publication No. 47-5125
An aluminum plate as described in Japanese Unexamined Patent Application Publication No. 2003-242242, which is anodized and then immersed in an aqueous solution of an alkali metal silicate, is also preferably used. Also, US Pat. No. 3,658
The silicate electrodeposition as described in No. 662 is also effective. Treatment with polyvinyl sulfonic acid as described in West German Patent No. 16214478 is also suitable.

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 Further, low molecular weight photoconductive compounds such as fluorenone derivatives, hydrazone derivatives, benzidine derivatives and stilbene derivatives, and polymer compounds such as polyvinylcarbazole and its derivatives can also be used. Further, various pigments, 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 are monoazo, bisazo, trisazo pigments, phthalocyanine pigments such as metal phthalocyanine or metal-free phthalocyanine, naphthalocyanine pigments, perylene pigments, indigo, thioindigo derivatives, quinacridone pigments, polycyclic quinone pigments, bisbenzimidazole. System pigments, squarylium salt pigments, azurenium salt pigments and the like. As the sensitization charge, "sensitizer", page 125, Kodansha 81987), "electronic photograph", 129 (19)
73) "Organic Synthetic Chemistry" 24 No. 11 1010
Known compounds described in (1966) and the like can be used. For example, there are pyrylium dyes, triarylmethane dyes, cyanine dyes, styryl dyes and the like.
These can be used alone or in combination of two or more. In addition, these charge generating agents have not only charge generating ability but also charge transporting ability, as a basic material,
A photoconductor can be prepared by dispersing and applying the charge generating agent in a binder. That is, it is not always necessary to use the organic photoconductive compound known as a charge transport agent together.

The binder resin used in the electrophotographic printing plate precursor used in the present invention is not particularly specified as long as it can elute and remove the non-image area after toner development, but it is not specified, but it is etched from the viewpoint of pollution or handling. As the liquid, an etching liquid mainly composed of an alkaline aqueous solution is preferably used. Therefore, a compound that can be removed by an alkaline aqueous solution is also preferable as the binding resin. For example, styrene / maleic anhydride copolymer, styrene / maleic anhydride monoalkyl ester copolymer, (meth)
Acrylic acid / (meth) acrylic acid ester copolymer, styrene / (meth) acrylic acid / (meth) acrylic acid ester copolymer, vinyl acetate / crotonic acid copolymer, vinyl acetate / crotonic acid copolymer / ( (Meth) acrylic acid ester copolymer, vinyl acetate / vinyl ester of C2-18 carboxylic acid / (meth) acrylic acid ester such as crotonic acid, styrene, vinyl acetate and the like and (meth) acrylic acid, itaconic acid, crotonic acid , Maleic acid, maleic anhydride, maleic anhydride monoalkyl ester, copolymers with carboxylic acid-containing monomers such as fumaric acid or acid anhydride group-containing monomers, (meth) acrylic acid amide, vinylpyrrolidone, phenolic hydroxyl group, Sulfonic acid group,
Copolymer containing a monomer having a sulfonamide group, a sulfonimide group, etc., a novolak resin obtained by condensing phenol, o-cresol, m-cresol or p-cresol with formaldehyde or acetaldehyde, partially saponified vinyl acetate Examples thereof include resins, polyvinyl acetal resins such as polyvinyl butyral, urethane resins having a carboxylic acid, and the like.

Among these, (meth) acrylic acid ester, styrene, vinyl acetate and the like and carboxylic acid-containing monomers or copolymers such as (meth) acrylic acid are excellent in electrophotographic property, etching property and printability. Therefore, it 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, actyl alcohol, benzyl alcohol, phenethyl. A copolymer of an aliphatic or aromatic alcohol such as alcohol, a (meth) acrylic acid ester and a (meth) acrylic acid can be used.

The electrophotographic printing plate precursor used in the present invention can be obtained by coating a photoconductive layer on a conductive substrate according to a conventional method. In the production of the photoconductive layer, a method of containing components constituting the photoconductive layer in the same layer, or a method of separating the charge carrier generating substance and the charge carrier transporting substance into different layers and the like are known, It can be created by either method. In the photoconductive layer, in addition to the photoconductive compound and the binder resin, various additives such as a plasticizer, a surfactant, a matting agent and the like may be added as necessary to improve the flexibility of the photoconductive layer and the properties of the coated surface. 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.

In the electrophotographic printing plate precursor used in the present invention, if necessary, an intermediate layer may be formed for the purpose of improving the adhesion between the conductive substrate and the photoconductive layer, the electrical characteristics of the photoconductive layer, the etching property, the printing property, and the like. Layers can be provided. Examples of the intermediate layer include casein, polyvinyl alcohol,
Various amino acids such as ethyl cellulose, polyacrylic acid, monoethanolamine, diethanolamine, triethanolamine, tripropanolamine, triethanolamine and their hydrochlorides, oxalates, phosphates, monoaminomonocarboxylic acids such as alanine, etc. Further, if necessary, an overcoat layer that can be removed during etching of the photoconductive layer can be provided on the photoelectric layer for the purpose of improving the electrical characteristics of the photoconductive layer, image characteristics during toner development, adhesion to toner, and the like. The overcode layer may be a mechanically matted layer or a resin layer containing a matting agent.

If the photoconductive layer is too thin, the surface potential required for development cannot be charged. On the contrary, if the photoconductive layer is too thick, side etching is likely to occur and a good printing plate cannot be obtained. . The film thickness of the photoconductive layer is 0.1 to 30 μ, preferably 0.5 to 10 μ. Regarding the content of the binder resin and the photoconductive compound in the photoconductive layer, if the content of the photoconductive compound is low, the sensitivity decreases. Therefore, the content of the photoconductive compound per 1 part by weight of the binder resin is 0.05 parts by weight or less. 1.2 parts by weight,
More preferably, it is used in the range of 0.1 part by weight to 1.0 part by weight.

In the present invention, the toner forming the image portion is not particularly limited as long as it has a resisting property with respect to the etching solution described later, but contains a resin component resisting the etching solution. It is preferable that As the resin component, for example, methacrylic acid, acrylic resin using acrylic acid and esters thereof, vinyl acetate resin, copolymer resin such as vinyl acetate and ethylene or vinyl chloride, vinyl chloride resin, vinylidene chloride resin,
Vinyl acetal resin such as polyvinyl butyral, polystyrene, copolymer resin such as styrene and butadiene, methacrylic acid ester, polyethylene, polypropylene and chlorinated products thereof, polyester resin (for example, polyethylene terephthalate, polyethylene isophthalate,
Bisphenol A polycarbonate), phenol resin, xylene resin, alkyd resin, vinyl-modified alkyd resin, gelatin, cellulose ester derivative such as carboxymethyl cellulose, wax, polyolefin, wax and the like.

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 it is 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. Examples of the alkaline compound include sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, potassium silicate, sodium metasilicate, potassium metasilicate, sodium phosphate, potassium phosphate, ammonia, and monoethanolamine, diethanolamine, and triethanolamine. Mention may be made of any organic and inorganic alkaline compounds such as amino alcohols such as ethanolamine. As described above, water or many organic solvents can be used as the solvent of the etching solution, but an etching solution mainly containing water is preferably used from the viewpoint of odor and pollution. If necessary, various organic solvents can be added to the etching solution mainly containing water. Examples of preferred organic solvents include lower alcohols such as methanol, ethanol, propanol, butanol, benzyl alcohol, and phenethyl alcohol, aromatic alcohols, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, and cellosolves. Further, as the etching liquid, a liquid containing a surfactant, a defoaming agent, and other various additives as needed is used.

The desensitizing liquid used in the present invention can be effectively used as a liquid containing an aqueous solution containing a hydrophilic polymer compound. As a specific hydrophilic polymer, for example,
Among natural macromolecules, starches such as cane starch, potato starch, tapioca starch, wheat starch and corn starch, carrageenan, laminaran, seaweed mannan, fungus, Irish moss, agar and those obtained from algae such as sodium alginate, Trolooi, Mannan, quince seed, pectin, tragacanth gum, karaya gum,
Plant mucilages such as xanthine gum, guar ingham, locust bingham, gum arabic, carop gum and benzoin gum, dextran, homopolysaccharides such as glucan and levan, and fermentation of microorganisms such as heteropolysaccharides such as succinoglucan and suntan gum. Examples include mucilages used, glue, gelatin, and collagen sugar proteins.

As semi-natural products (semi-synthetic products), in addition to propylene glycol alginate, biscodes, methyl cellulose, ethyl cellulose, methyl ethyl cellulose, carboxymethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose,
Examples thereof include fibrin derivatives such as hydroxypropyl ethyl cellulose and hydroxypropyl methyl cellulose phthalate, and modified starch. Processed starches include roasted starch such as white dextrin, yellow dextrin and british gum, fermented modified dextrin such as fermented dextrin and Schardinger dextrin, acid decomposed starch shown in solubilized starch, oxidized starch shown in dialdehyde starch, modified Pregelatinized starch such as pregelatinized starch and non-modified pregelatinized starch, phosphate starch, fatty starch, starch starch sulfate, nitrate nitrate, starch xanthate and esterified starch such as carbamate starch, carboxyalkyl starch, hydroxyalkyl starch, sulphate Faalkyl starch,
Etherified starch such as cyanoethyl starch, allyl starch, benzyl starch, carbamylethyl starch and dialkylamino starch, crosslinked starch such as methylol crosslinked starch, hydroxyalkyl crosslinked starch, phosphoric acid crosslinked starch and dicarboxylic acid crosslinked starch, starch / polyacrylamide Copolymers, starch / polyacrylic acid copolymers, starch / polyvinyl acetate copolymers, starch / polyacrylonitrile copolymers, cationic starch / polyacrylic acid ester copolymers, cationic starch / vinyl polymer copolymers Examples thereof include coalesce, starch / polystyrene maleic acid copolymer, and starch / polyethylene oxide copolymer and other starch graft copolymers.

In addition to polyvinyl alcohol, synthetic products include partially acetalized polyvinyl alcohol, allyl-modified polyvinyl alcohol, polyvinyl methyl ether, polyvinyl ethyl ether, polyvinyl isobutyl ether, and other modified polyvinyl alcohol, sodium polyacrylate, and polyacrylate ester moieties. Saponification products, polyacrylic acid ester copolymer partial saponification products, polyacrylic acid derivatives and polymethacrylic acid derivatives such as polymethacrylic acid salts and polyacrylic amides, polyethylene glycol, polyethylene oxide, polyvinylpyrrolidone, polyvinylpyrrolidone / vinyl acetate copolymerization And carboxyvinyl polymer, styrene / maleic acid copolymer, styrene / crotonic acid copolymer and the like.

The desensitizing solution used in the present invention preferably further contains a metal salt of a strong acid, whereby the desensitizing action can be further enhanced. Specific examples of the metal salt of a strong acid include sodium, potassium, magnesium, calcium and zinc salts of nitric acid, sulfuric acid, chromic acid and the like, sodium fluoride, potassium fluoride and the like. When a metal salt of a strong acid is used, it is preferably used at a pH of 1 to 5, more preferably 2 to 4.5. Further, instead of the metal salt of the strong acid, the general formula m
SiO ₂ / nM ₂ O (M: alkali metal atom, m / n =
The desensitizing action can be enhanced even when the silicate represented by 0.5 to 8.5) is contained in the desensitizing solution. As a specific liquid silicate, sodium silicate, potassium silicate, lithium silicate or the like can be used. The silicate used in the present invention is preferably used in an amount of about 0.4% by weight to about 40% by weight, and preferably about 0.8% by weight to about 25% by weight in the total desensitizing solution. When a silicate is used in the desensitizing solution used in the present invention, it is preferably used in a pH range of 8 to 14, more preferably 9 to 13. In the present invention, various additives such as a surfactant and a wetting agent may be used in the desensitizing solution, if necessary. The desensitizing solution used in the present invention comprises an aqueous solution of the hydrophilic polymer compound as described above. For example, US Pat. No. 425399.
The emulsion-type desensitizing solutions described in the specifications of No. 9, No. 4268613, No. 4348954 and the like can also be used.

[0030]

As described above, at least in the electrophotographic lithographic printing plate precursor having the photoconductive layer provided on the conductive substrate, at least the step of charging, the step of exposing, the step of developing with toner, the toner In a method for producing an electrophotographic lithographic printing plate by a step including a fixing step and a step of removing a photoconductive layer other than a toner image, an image is formed in the step of removing the photoconductive layer other than a toner image and / or the subsequent step. By removing the toner layer at the peripheral edge portion, it was possible to obtain a clear printed matter without causing reproducibility of the image line width due to printing.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing an embodiment of the present invention.

FIG. 2 is a schematic sectional view showing another embodiment of the present invention.

FIG. 3 is a schematic sectional view showing another embodiment of the present invention.

FIG. 4 is a schematic sectional view showing another embodiment of the present invention.

FIG. 5 is a schematic sectional view showing another embodiment of the present invention.

FIG. 6 is a schematic sectional view showing another embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Electrophotographic printing plate 2 Etching process part 3 Squeeze part 4 Water washing part 5 Gum liquid application part 6 Drying part 7, 8, 9 Conveying roller for nipping and conveying the electrophotographic printing plate 10 Squeeze roller 11, 12, 13 Electrophotography Conveying rollers for nipping and conveying the printing plate 14 Guide rollers 15 Circulation pump 16 Injection nozzle 17 Drain pipe 18 Roller 19, 20 Circulation pump 21 Dryer 22 Brush roller 23 Etching tank 24 Injection nozzle 25 Spray nozzle 27, 28 Electrophotographic printing plate Conveying roller for nipping and conveying 29 Squeeze roller 30, 31, 32, 33 Conveying roller for nipping and conveying electrophotographic printing plate 34 Guide roller 35 Circulating pump 36 Injection nozzle 37 Etching liquid tank 38 Water tank 39 Gum liquid tank 40 brush roller 41 circulation pump 42 Injection nozzle 43 Circulation pump 44 Sreep nozzle 45 Washing / drying unit 46 Toner removing unit 47 Adhesive roller 48 Receiving roller

Claims (2)

[Claims] 1. A step of at least charging using an electrophotographic lithographic printing plate precursor having a photoconductive layer provided on a conductive substrate, a step of exposing, a step of developing with toner, a step of fixing toner, a toner image. In a method for producing an electrophotographic lithographic printing plate by a step including a step of removing a photoconductive layer other than a toner image, a step of removing a photoconductive layer other than a toner image and / or a toner layer at an image peripheral edge portion in the subsequent step A method for producing an electrophotographic lithographic printing plate, which comprises removing 2. An electrophotographic lithographic printing plate manufacturing apparatus including at least the charging step, the exposing step, the toner developing step, the fixing step, and the photoconductive layer eluting step, An apparatus for producing an electrophotographic lithographic printing plate, characterized in that means for removing the toner layer at the peripheral edge of the image is provided in the post-process section.