JPH0624169A - Processing method of protecting gum liquid - Google Patents

Abstract

PURPOSE:To feed and apply a protecting gum liquid uniformly for a long term in a processing device of a lithographic printing plate, by providing a gum liquid feed means and a cleansing liquid feed means at a contact part between a protecting gum liquid applying roll and a liquid measuring roll, and feeding the cleansing liquid to a group of rolls of a protecting gum liquid processing liquid. CONSTITUTION:A protecting gum liquid application zone D is constituted of a protecting gum liquid feed part comprising a protecting gum liquid feed means 45, a liquid measuring roll 43, a protecting gum liquid applying roll 40 and a backup roll 41, and a cleansing liquid feed means 60, a protecting gum liquid storing tank 8, and an excessive protecting gum liquid primary storing tank 6. After a protecting gum liquid is applied, while rolls 40-41 are kept rotating, a cleansing liquid 49 is supplied to clean the zone. The cleansing liquid 49 is supplied to the cleansing liquid feed means 60 via a liquid feed pump 99 and an e1ectro liquid valve 131 from a storing tank 9. The cleansing liquid 49 after cleansing is discharged to a waste liquid secondary storing tank 21 by a valve 107.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method in which a non-image area is dissolved and removed by an alkaline processing solution, and subsequently a protective gum solution is applied while roll-conveying a planographic printing plate whose plate surface is rinsed with a rinse solution. The present invention relates to a method for treating a protective gum solution remaining in a roll after treatment with the protective gum in the treating apparatus.

[0002]

2. Description of the Related Art A non-image area alkali dissolution removing type lithographic printing plate contains an actinic ray-inducing treatment liquid solubilizing substance or an actinic ray curable substance accompanied by a chemical structure change by actinic rays on a hydrophilic support. A photosensitive lithographic printing plate (so-called PS plate) provided with a photosensitive layer is known and is widely used for heavy printing that requires high printing durability. These are printing plates which have a sensitivity capable of forming an image in a light source (for example, a semiconductor laser) of scanning exposure, and which are easy to handle in a bright room, have not been generalized yet, and are pre-recorded with an image-recorded silver. The salt photographic film original plate is exposed by closely contacting it with the photosensitive surface of the printing plate, thereby forming a cured part corresponding to the image part in the final printed matter or a solubilized part of the processing liquid corresponding to the non-image part, thereby forming a non-image. The partial photosensitive layer is dissolved and removed by an alkaline processing liquid.

Further, an electrophotographic lithographic printing plate which forms an image by utilizing an electrophotographic technique is also known, and a printing plate compatible with scanning exposure is also manufactured. A non-image area alkali-removing lithographic printing plate utilizing electrophotographic technology is a support in which an ink-receptive photoconductive layer in which an organic photoconductive substance is dispersed in a resin is provided on a hydrophilic support. If it is strongly adhered to the plate, the ink receiving layer is thicker than the PS plate, so that it has printing durability equal to or higher than that of the PS plate. These are used as printing plates by forming a toner image on the photoconductive layer by an electrophotographic method, and then subjecting a non-image portion to an elution treatment with an eluent containing an alkaline agent.

Usually, in these non-image area alkali dissolution removing type lithographic printing plates, a plate surface protective agent (so-called protective gum solution) is applied as a final step of the plate making process. The purpose is to cover the entire plate surface with a plate surface protective agent so that not only the hydrophilicity of the surface of the non-image part support is retained, but also the plate is preserved for printing after plate making or until reuse, printing machine. It prevents the contamination caused by the adhesion of fingerprints, fats and oils, dust, etc. during handling until it is attached to the product, and improves the scratch resistance. To prevent the occurrence of.

Conventionally, as an apparatus (structure) for applying a protective gum solution to a lithographic printing plate, an excess amount is supplied by directly supplying a liquid from a shower pipe to an upper roll and / or a printing plate. A protective gum solution was intermittently supplied from a device such as a device for measuring the protective gum solution with an unloading roll or a pipe passed at a right angle to the printing plate conveying direction from a velor pump or the like, and a plurality of them were provided in the axial direction of the pipe. There is known a device in which the liquid is dropped from a through hole onto a lithographic printing plate, then spread by a roll, and coating is performed by supplying a smaller amount of liquid.

Further, the upper roll of the pair of conveying rolls of the protective gum solution applying section, which is disclosed in Japanese Utility Model Publication No. 59-30141, is made of a high liquid retaining material and adheres to the lower roll. The above-mentioned liquid is transferred to the upper roll to improve the uniform application of the protective gum liquid on both sides of the printing plate.
As described in Japanese Patent Publication, for a roll pair in which the axial center of the upper roll is shifted to the rear in the transport direction, a protective gum solution is supplied to the wedge portion on the transport roll engagement side (front in the transport direction). Particularly, an apparatus for improving coating defects at the front and rear ends is disclosed in JP-A-63-1673.
Japanese Patent Laid-Open No. 65-65 discloses an apparatus that conveys a plate downward in the horizontal direction and arranges only a pair of squeeze rolls on the downstream side to simplify the structure and make the device compact.

In these conventional protective gum solution coating apparatuses, the protective gum solution circulates and reuses the processing surplus, and the liquid is supplied from the protective gum solution storage tank by a pump to a roll from a shower pipe. And / or the method of discharging onto the printing plate is generally used, and as mentioned above, uniform application of the protective gum solution is achieved by arranging a liquid supply roll that controls transportation, application of the protective gum solution, spreading, and squeezing solution. And materials were devised, and the means and supply conditions for supplying directly to the roll and / or the printing plate, especially the actual processing problems caused by the change in the liquidity mainly due to the aging of the protective gum solution, were taken into consideration. Was not done.

As a result, when the liquid is discharged only when it is necessary for the treatment, the protective gum liquid remaining in the discharge hole of the shower pipe dries and induces clogging, which is a cause of liquid supply failure. Further, in many conventional protective gum solution coating apparatuses, a method of finally controlling the coating amount of the protective gum solution by a roll pair and a press squeezing solution is employed. After the treatment, the protective gum solution remains concentrated even after the treatment, and the rolls adhere to each other, resulting in poor rotation, damage to the roll drive system, deterioration of the roll surface, coating unevenness, and defective drawing. There were many things.

Therefore, in order to prevent the above problems, the pressure applied to the rolls is released after the lithographic printing plate treatment to keep the rolls in a non-contact state, or before the protective gum solution is concentrated, the roll surface is treated. Artificial wiping and cleaning are also performed. However, the protective gum solution remains in the lowest part of both rolls even in the non-contact state, although it is less than in the roll contact state, and since the conventional protective gum solution is reused by circulation, it is often used. As a result, the cleaning liquid, solidified protective gum liquid, or abrasion debris of the wiping and cleaning tool are mixed in the circulating protective gum liquid, resulting in a decrease in the solid gum concentration and a decrease in the protective gum capacity, or a defective circulation of the circulation system or liquid. There was a risk of clogging the supply means.

[0010]

DISCLOSURE OF THE INVENTION According to the present invention, a non-image area is dissolved and removed with an alkaline processing liquid, and then a protective gum solution is applied while roll-transporting a lithographic printing plate whose plate surface has been rinsed with a rinse liquid. The method of treating the protective gum solution remaining on the roll after the protective gum treatment in the treating apparatus for treating by means of the time-dependent change in the protective gum solution treatment, more specifically, by the concentration drying of the protective gum solution. -Providing a protective gum solution treatment method which prevents various problems caused by sticking to a roll and adhesion between rolls and enables uniform supply and coating treatment of a stable protective gum solution for a long period of time. . For more details,
It is an object of the present invention to provide a method for treating a protective gum solution which does not substantially discharge a waste solution other than liquid exchange by removing the protective gum solution adhering to the roll with a cleaning solution and supplementing the mixed solution with the rinse solution.

[0011]

[Means for Solving the Problems] As a result of studies for solving the above problems, the non-image area was dissolved and removed by an alkaline processing liquid, and then a lithographic printing plate whose plate surface was rinsed with a rinse liquid was rolled and conveyed. A processing device for applying and processing a protective gum solution, and a protective gum solution coating roll for applying and spreading a protective gum solution on a plate surface while conveying a lithographic printing plate,
A liquid measuring roll, which is in front of the roll in the plate conveying direction and contacts a part of the outer periphery of the roll to limit the amount of the protective gum liquid applied to the planographic printing plate, and a protective gum liquid coating roll. Lithographic printing by a protective gum solution treating device having a protective gum solution supplying means for supplying a protective gum solution to a contact portion with a liquid measuring roll and a cleaning solution supplying means for supplying a cleaning solution to the corresponding contact portion for cleaning. After the plate is treated with a protective gum solution, the cleaning solution is supplied by the cleaning solution supply means.
This was achieved by supplying the cleaning solution to the roll group and removing and discarding the protective gum solution remaining on the roll.

The processing method of the present invention will be described in detail below. The processing apparatus according to the present invention is a protective gum solution in a protective gum solution applying section after a rinsing solution is supplied to the plate surface while rinsing while transporting a lithographic printing plate from which a non-image area is dissolved and removed by an alkaline processing solution. A device for applying a coating,
At least the protective gum solution application section is applied to the planographic printing plate by contacting with a protective gum solution application roll for applying and spreading the protective gum solution and a part of the outer periphery of the roll in front of the roll in the plate conveying direction. A protective gum solution supplying means for supplying a protective gum solution to both roll contact parts, and a cleaning solution to both roll contact parts. It has a cleaning liquid supply means for supplying.

In the present apparatus, the protective gum solution is a protective gum solution reservoir formed by the protective gum solution supplying means and the contact areas of both the protective gum solution application roll and the liquid metering roll. After being supplied to the groove in the roll axial direction (plate width direction) and once stored, it is weighed from the gap between both roll contact portions over the entire width in the axial direction of the roll, and the protective gum solution coating roll is applied. It flows down continuously. The lithographic printing plate carried into the protective gum solution coating section is sandwiched by a protective gum solution coating roll and a backup roll arranged below the protective gum solution coating roll to assist the transportation of the lithographic printing plate. At the same time as being conveyed and conveyed, the protective gum solution that has flowed down from the contact portion is spread and squeezed by the roll pair.

Therefore, except during the passage of the planographic printing plate, the protective gum solution flows from the protective gum solution supply means through the protective gum solution coating roll and the liquid metering roll to flow down from the backup roll. Protective gum solution coating roll / solution metering roll pair and protective gum solution coating roll / backup roll
Some protective gum solution will remain at both contact parts of the pair of coatings even after passing through the lithographic printing plate. Therefore, if each roll is left in contact after the lithographic printing plate treatment, the protective gum solution is dried and concentrated while remaining particularly in the roll contact portion,
The rolls are strongly adhered to each other and are hard to rotate, and abnormal torque is required at the time of start-up, which causes wear and eventually damage of the roll drive system. Therefore, in the present invention, a lithographic printing plate is treated with a protective gum solution while being sandwiched and conveyed by a protective gum solution coating roll / backup roll pair, and is then discharged from the protective gum solution coating section, and then a cleaning liquid supply means is provided. Thus, a cleaning liquid is supplied to these rolls to remove the protective gum liquid component remaining in the rolls.

The cleaning liquid according to the present invention is rapidly mixed with at least the protective gum liquid to be used, particularly the film-forming component when it is in a liquid state to reduce the viscosity and improve the fluidity.
It is desirable to have the property of easily replacing the protective gum solution on the surface to be cleaned such as a roll. The most commonly used solvent for the protective gum solution is water, and since water as a cleaning solution also meets the above conditions, the cleaning solution may be composed of only water, but in order to enhance the cleaning effect, the cleaning solution is protected. It is preferable to include a type of surfactant that does not cause aggregation with the gum liquid component.

The surfactant used in the present invention includes:
For example, polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene polystyrylphenyl ether, polyoxyethylene fatty acid ester, sorbitan fatty acid ester, pentaerythritol fatty acid ester, polyoxy Nonionic surfactants such as ethylene sorbitan fatty acid ester, glycerin fatty acid ester, pentaerythritol fatty acid ester, alkynediol, polyoxyethylene-added alkynediol, fatty acid salts, abietic acid salts, alkane sulfonates, hydroxy Alkane sulfonates, dialkyl sulfosuccinates, alkylbenzene sulfonates, alkylnaphthalene sulfonates, alkylphenoxypolyoxyethylenepropyl sulfonates, Lioxyethylene alkylsulfophenyl ether salts, N-alkylsulfosuccinic acid monoamide salts, petroleum sulfonates, fatty acid alkyl ester sulfate ester salts, alkyl sulfate ester salts, polyoxyethylene alkyl ether sulfate ester salts, poly Oxyethylene alkylphenyl ether sulfate ester salts, fatty acid monoglyceride sulfate ester salts, alkyl phosphate ester salts, polyoxyethylene alkyl ether ester phosphate salts, polyoxyethylene alkylphenyl ether phosphate ester salts, styrene / maleic anhydride Anionic surfactants such as partially saponified acid copolymers, partially saponified olefin / maleic anhydride copolymers, naphthalene sulfonate formalin condensates, aminocarboxylic acids, and sulfur Betaines,
Examples include amphoteric surfactants such as aminosulfates and imidazolines. Among the above-mentioned surfactants, those having polyoxyethylene can be replaced with polyoxyalkylenes such as polyoxymethylene, polyoxypropylene and polyoxybutylene, and those surfactants are also included. . These surfactants may be used alone or in combination of two or more kinds, and 0.001 to 5% by weight, more preferably 0.01% by weight in the cleaning liquid.
It is used by mixing in the range of 1 wt%.

If desired, the cleaning liquid according to the present invention may further contain known water-soluble organic solvents, acidic buffers, preservatives, rust preventives, chelating agents, pH adjusting agents and the like in appropriate amounts. I can. The cleaning liquid used for cleaning may be reused by circulating under a certain condition, or may be mixed with the circulating protective gum solution and used, but it is replenished to the rinse solution to be treated prior to the protective gum solution treatment. Be better. By adding the used cleaning liquid to the rinse liquid, not only the rise in pH of the rinse liquid can be suppressed, but also the decrease in the amount of rinse liquid such as evaporation of the liquid and taking it out to the protective gum liquid application part can be prevented. . In this case, the rinse liquid and the rinse replenishing liquid components may be contained in the cleaning liquid in a range that does not impair the cleaning effect of the protective gum liquid.

The cleaning liquid according to the present invention is supplied by the cleaning liquid supply means arranged in the processing apparatus used in the present invention. As the cleaning liquid supply means, in addition to showers and sprays, conventionally known application means may be used, and since the discharge pressure is not particularly required, the tip of the liquid supply pipe may be placed at the supply position as it is. Similar to the protective gum solution, the cleaning liquid supply position may be only the protective gum solution application roll / liquid metering roll contact portion, but the protective gum solution application roll / backup roll contact portion is in the transport direction front side. The cleaning effect is further improved by supplying it to the side. Further, the protective gum solution supply means and the cleaning solution supply means may be combined. If the amount of the protective gum solution supplied by the protective gum solution supplying means is small, the inside of the protective gum solution supplying means can be washed. The cleaning liquid is supplied by a liquid supply pump with a dedicated storage tank. If the cleaning liquid is water,
The cleaning liquid may be supplied to the cleaning liquid supply means without passing through the liquid storage tank.

Means for carrying out mechanical cleaning by contacting with a roll group such as a brush roll may be provided in advance during cleaning, but contact with the protective gum solution before the protective gum solution becomes sticky. If a cleaning liquid is supplied to the roll group or the like, it can be easily removed from the roll group, so that it is not particularly necessary to provide a mechanical contact cleaning means. However, since the protective gum once dried and fixed is not easily redissolved only by supplying the cleaning liquid, it is necessary to start the cleaning before supplying the cleaning liquid, more preferably before it becomes tacky. The timing of washing is not specified unconditionally because it is defined by the type of evaporating component (solvent) and its concentration in the protective gum solution component, but it is better to start the washing within 30 minutes, and more preferably after carrying out the plate. Within 15 minutes. The most preferable cleaning start time is until the protective gum solution applied to the protective gum solution application roll / liquid metering roll contact portion is completely drained.

The amount of the cleaning liquid to be supplied at one time is preferably as large as possible without considering the waste liquid, but substantially the minimum amount of the cleaning liquid replacing the protective gum liquid on the roll group to which the protective gum liquid adheres is replaced. The amount is sufficient. Specifically, a protective gum solution coating roll
It is sufficient that the liquid metering roll contact portion is filled. If the roll is rotated while the cleaning liquid is full, the cleaning liquid is gradually measured while diluting and replacing the protective gum liquid coating roll and the protective gum liquid on the outer circumference of the liquid measuring roll, and is the backup roll. Can also be washed. In particular, if the cleaning liquid used for cleaning is used as a part of a replenishing liquid such as a circulating rinse liquid, the amount of cleaning liquid may be increased within a desired range. If the protective gum solution is discarded without being circulated and refilled with another processing solution, basically there is no need for fatigue replacement of the protective gum solution,
Substantially no waste liquid is discharged from the protective gum solution coating zone.

In particular, in the case of producing a large number of plates, the pH of the circulating rinse solution gradually increases due to the alkaline processing liquid brought together with the alkali-processed lithographic printing plate. The photoconductive layer in the image area will dissolve and induce image thinning and image peeling. Conversely, if an acidic substance is added carelessly to lower the pH of the circulating rinse solution, it will agglomerate with the contaminated basic substance. However, if the protective gum solution and the washing solution are weakly acidic, they are replenished little by little, so there is almost no possibility of causing aggregation or gelation, and the pH increase of the circulating rinse solution becomes slow. Therefore, it is preferable as the entire processing system.

The protective gum solution according to the present invention contains at least a hydrophilic polymer compound having a self-filming property when dried, and if desired, further includes a lipophilic substance, a pH adjusting agent, a preservative,
It comprises a surfactant, water and the like. Further, the form of the protective gum solution can be produced in any manner such as emulsion type, suspension type, non-emulsion non-suspension type by appropriately selecting the surfactant and lipophilic substance to be contained, etc. The suspension type protective gum solution is preferably used because it not only has good removability at the time of washing but also suppresses deterioration of the oil sensitivity of the image portion of the lithographic printing plate.

Natural polymers in the hydrophilic polymer compound used in the protective gum solution include starches such as potato starch, sweet potato starch, wheat starch, tapioca starch, and cone starch, and the like.
Color Guinan, Laminaran, Seaweed Mannan, Funori,
Algae extracts such as Irish moss, agar, and alginate, grated yam, yam, glucomannan, quince seed, pectin, gum arabic, karaya gum, xanthine gum, carob gum, guar gum, locust bean gum, tamarind. Seed gum, tragacanth gum,
And vegetable mucilage such as benzoin gum, dextran,
Homopolysaccharides such as glucan, xanthan gum, and levan, and succinoglucan, pullulan, cardran,
And microbial mucilage such as heteropolysaccharide such as xanthan gum,
Examples include proteins such as glue, gelatin, casein, and collagen.

As the semi-natural product (semi-synthetic product), in addition to propylene glycol alginate, viscose,
Methyl Cellulose, Ethyl Cellulose, Methyl Ethyl Cellulose, Hydroxyethyl Cellulose, Carboxymethyl Cellulose, Hydroxypropyl Cellulose, Hydroxypropyl Methyl Cellulose, Hydroxypropyl Ethyl Cellulose, Carboxymethyl Hydroxyethyl Cellulose and fibrin derivatives such as hydroxypropylmethylcellulose-phthalate, modified gum, and modified starch are mentioned. Modified gums include carboxymethyl guar gum, hydroxypropyl guar gum, hydroxyethyl guar gum, and the like. Modified starches include white dextrin, yellow dextrin, and culture-baked starch such as bridish gum, enzyme-modified dextrins such as enzyme dextrin and Schardinger dextrin, oxidized starch such as dialdehyde starch, modified and non-modified alpha. −
-Pregelatinized starch such as modified starch, starch phosphate, fatty acid starch, starch sulfate, nitrate starch, starch xanthate, and esterified starch such as carbamic acid starch, hydroxyalkyl starch, carboxyalkyl starch, sulfoalkyl starch, cyanoethyl starch , Allyl starch, benzyl starch, carbamylethyl starch, and etherified starch such as dialkylamino starch, methylol crosslinked starch, hydroxyalkyl crosslinked starch, phosphoric acid crosslinked starch, and dicarboxylic acid crosslinked starch, and the like crosslinked starch, Starch polyacrylamide copolymer, starch polyacrylonitrile copolymer, cationic starch polyacrylic acid ester copolymer, cationic starch vinyl polymer copolymer, starch polystyrene maleic acid copolymer,
And starch graft copolymers such as starch polyethylene oxide copolymers.

As the synthetic product, polyvinyl alcohol other partially acetalized polyvinyl alcohol, allyl-modified polyvinyl alcohol, polyvinyl methyl ether, polyvinyl ethyl ether, polyvinyl isobutyl ether, etc. Modified polyvinyl alcohol, polyacrylate,
Partially saponified polyacrylic acid ester, polymethacrylic acid salt, and polyacrylic acid and polymethacrylic acid derivatives such as polyacrylic amide, polyethylene glycol,
Examples thereof include polyethylene oxide, polyvinylpyrrolidone, vinylpyrrolidone / vinyl acetate copolymer, carboxyvinyl polymer, styrene / maleic acid copolymer, and styrene / crotonic acid copolymer. Among these, those obtained from algae, vegetable mucilages, fibrin derivatives, modified starches, propylene glycol alginate esters, and synthetic products are preferably used because they have good film forming properties on printing plates.

Examples of the lipophilic substance used in the protective gum solution include a plasticizer, a fatty acid, a fatty oil, a monovalent alcohol and a wax, as well as a lipophilic resin used as a vehicle for a printing ink. Examples of the lipophilic resin include phenol formaldehyde resin, novolac type phenol resin such as t-butylphenol formaldehyde resin, xylene resin obtained by condensing phenol and xylene with formaldehyde, phenol and mesitylene. Formaldehyde condensed resin, polyhydroxystyrene, brominated polyhydroxystyrene, cash-resin, partially esterified product of styrene / maleic anhydride copolymer, melamine resin,
Examples thereof include alkyd resins, polyester resins, epoxy resins, rosins, hydrogenated rosins, modified rosins such as rosin esters, and petroleum resins such as gilsonite.

Examples of the plasticizer include dibutyl phthalate, dioctyl phthalate, di- (2-ethylhexyl) phthalate, dinonyl phthalate, didecyl phthalate, dilauryl phthalate, butyl benzyl phthalate and the like. Acid diesters, dioctyl azelate, dioctyl adipate, dibutyl sebacate, di- (2-ethylhexyl) sebacate, dioctyl sebacate and other aliphatic dibasic acid esters, epoxidized soybean oil Such as epoxidized triglycerides, tricresyl phosphate, trischloroethyl phosphate, and other phosphoric acid esters, benzyl benzoate, and other benzoic acid esters, and the like, and the freezing point is 15 ° C.
In the following, compounds having a boiling point (normal pressure) of 300 ° C. or higher are mentioned.

Examples of the fatty acid include caproic acid, enanthic acid, caprylic acid, undecyl acid, lauric acid, tridecyl acid, myristic acid, pentadecyl acid, palmitic acid,
Saturated fatty acids such as heptadecyl acid, stearic acid, nonadecanoic acid, arachidic acid, behenic acid, lignoceric acid, cerotic acid, heptacosanoic acid, montanic acid, melissic acid, laxeric acid, isovaleric acid, and acrylic acid, methacrylic acid, crotonic acid. , Isocrotonic acid, undecylenic acid, oleic acid, elaidic acid, cetoleic acid, sorbic acid,
Unsaturated fatty acids such as erucic acid, brassic acid, linoleic acid, linolenic acid, arachidonic acid, propioic acid, stearolic acid, sardine acid, tariline acid and licanoic acid can be mentioned. These are preferably liquid at 50 ° C. and have 5 to 25 carbon atoms, more preferably 8 to 2 carbon atoms.
It is 1.

In order to adjust the pH of the protective gum solution,
Various pH adjusting agents can be added to the protective gum solution. In particular,
In order to circulate and reuse the squeezed excess protective gum solution for more stable processing of a large number of lithographic printing plates, it is desirable that the solution pH does not change. It is desirable to contain at least one of the salts. Suitable acids and water-soluble salts include hydrochloric acid, nitric acid,
Inorganic acids such as sulfuric acid, phosphoric acid, and polyphosphoric acid, acetic acid, benzoic acid, glycolic acid, lactic acid, propionic acid, oxalic acid,
Tartaric acid, succinic acid, maleic acid, fumaric acid, malonic acid,
Examples thereof include water-soluble organic acids such as phthalic acid, malic acid, glutaric acid, pimelic acid, adipic acid, citric acid, trimellitic acid, trimesic acid, p-toluenesulfonic acid, and the like, and salts thereof. In the salt form, water-soluble alkali metal salts and ammonium salts are preferred. Of these, more preferred acids and / or water-soluble salts are phosphoric acid, polyphosphoric acid, oxalic acid, tartaric acid, succinic acid, maleic acid, fumaric acid, malonic acid, phthalic acid, malic acid, glutaric acid, pimelic acid, A polybasic acid such as adipic acid and citric acid and an alkali metal or ammonium salt thereof, more preferably one having an acid dissociation constant (pKa) of at least 4.5 to 6.0 among the above acids, are concerned with the present invention. It can be suitably used as a protective gum solution. Examples of polybasic acids having an acid dissociation constant of at least 4.5 to 6.0 include adipic acid, citric acid, glutaric acid, succinic acid, pimelic acid, maleic acid, malonic acid, malic acid and the like. Such acids and / or water-soluble salts can be used alone or in combination of two or more, and if desired, a suitable acid or alkaline agent can be added to adjust the liquid pH.

If the protective gum solution propagates due to the inclusion of bacteria in the air over time, the protective gum solution not only deteriorates the protective gum effect, but also produces an offensive odor, which is not preferable. Therefore, it is desirable that the protective gum solution according to the present invention further contains a preservative and / or a bactericide. Preservatives and fungicides include phenol, cresol, o-phenylphenol, p-chloro-m.
-Phenolic compounds such as xylenol, 2 ', 4', 5-trichloro-2-phenoxyphenol, alkylbis (aminoethyl) glycine, bis (alkylaminoethyl)
Glycine-based compounds such as glycine, guanidine-based compounds such as polyhexamethylene biguanidine, carboxylic acids such as dehydroacetic acid and benzoic acid esters, esters, and salts thereof, hexahydro-1,3,5-tris (2-hydroxyethyl) -S-triazine, hexahydro-1,3,5-triethyl-S-triazine and other triazine compounds, benzisothiazolone, isothiazolone and its isothiazolone compounds such as derivatives thereof, 2- (thiocyanomethylthio) benzimidazole 4,5,6,7-tetrachloro-
Imidazole compounds such as 2-trifluoromethylbenzimidazole and perbentazole, pyridine compounds such as 2,3,5,6-tetrachloro-4-methylsulfonylpyridine and dithiobis (benzmethylamide) ) And other amide compounds, and other N, N-dimethyl-N'-phenyl-N'-
(Fluorodichloromethylthio) -sulfamide and the like. Particularly, isothiazolone compounds, acid ester compounds, and phenol compounds are preferable. These antiseptic / bactericidal agents may be used alone or in combination of two or more kinds. Before adding to the washing solution, it is preferable to dissolve it in water and a suitable organic solvent in advance. The amount added to the washing solution is
It is necessary to adjust depending on the type of compound used (bactericidal activity), the bacterial species mixed in the protective gum solution and the amount thereof, but usually 1
In the range of 0 to 30,000 ppm, more preferably 50 to
It is preferable to use it in the range of 10000 ppm.

In addition, the protective gum solution according to the present invention further comprises a wetting agent such as lower glycol such as ethylene glycol, glycerin, and triethylene glycol, and a colloidal water containing colloidal alumina and colloidal silica. Natural and synthetic clay minerals such as metal oxides, laponite, smectite, and mica, nitrilotriacetic acid, ethylenediaminetetraacetic acid, 1-hydroxyethane-1,1-diphosphonic acid,
Also, chelating agents such as trimethylenetetraminehexa (methylenephosphonic acid) and salts thereof, and surfactants used in the detergent according to the present invention may be added.

As the protective gum solution supplying means, a method of supplying directly to the plate surface by a shower pipe which has been most commonly used in the past, or a method of supplying it through a roll or a rectifying means, or Japanese Patent Application No. 4-35223. It is possible to use a desired supply means such as a liquid supply system using a protective gum liquid supply tool for controlling the closing and opening of the liquid discharge hole by compressed air as described in No. The latter is more preferable because the risk of liquid supply failure due to clogging of the liquid supply hole can be reduced in the case of intermittent supply.
The discharge amount of the protective gum liquid may be supplied to the plate surface in an excessive amount, or may be measured by the liquid supply means in advance at the time of supplying the contact portion and then supplied. As long as the liquid is supplied by the liquid supply means measuring method, the protective gum liquid may be discarded without being recycled. The liquid supply amount of the protective gum liquid according to the present invention to the printing plate depends on the surface roughness of both the protective gum liquid coating roll and the liquid measuring roll in the processing apparatus used in the present invention. It can be controlled by the average gap between the rolls, which is predominantly defined. By this method, a certain amount of protective gum solution can be supplied almost uniformly in the width direction of the printing plate, and the protective gum solution coating roll further spreads the protective gum solution on the printing plate, so that the printing plate surface is more evenly distributed. Applied to.

The substantial amount of liquid applied to the printing plate is the surface roughness of the protective gum liquid coating roll and the backup roll which is below the protective gum liquid coating roll and assists the transportation of the printing plate. It is specified by the pressing pressure of the protective gum solution coating roll of the above. The solid coating amount is expressed by the non-volatile concentration of the protective gum solution and the liquid coating amount, which is preferably the minimum amount within the range defined by the characteristics of the coated protective gum film. The smaller the volatile matter application amount from the burden of drying, the better, and the nonvolatile content concentration of the protective gum solution is the form of the protective gum solution (emulsion type,
Although it depends on the suspension type, non-emulsion non-suspension type) and dynamic viscosity, the lower the cleaning efficiency is, the better. Therefore, it is desirable to set at least on the side of the apparatus so that the liquid application amount is small.

The protective gum solution according to the present invention can be used for various lithographic printing plates. In particular, an aluminum substrate having a surface hydrophilic treatment is used as a support, and a photosensitive layer having a photosensitive layer on the surface-treated surface thereof is used. Image exposure, toner development, and elution treatment of a lithographic printing plate obtained by subjecting a lithographic printing plate (PS plate) to image exposure and alkali development, and an electrophotographic lithographic printing plate having a photoconductive layer on the same support. The lithographic printing plate thus obtained can be preferably used.

The PS plate that can be used in the present invention is a diazo resin (salt of a condensate of p-diazophenylamine and paraformaldehyde) as described in British Patent 1,350,521. And a shellac and a photosensitive layer comprising a mixture of shellac and a diazo resin and a hydroxyethyl methacrylate unit or hydroxyethyl acrylate described in British Patent Nos. 1,460,978 and 1,505,739. Negative PS having a photosensitive layer composed of a mixture with a polymer having a repeating unit as a main repeating unit
Plates, and o-quinonediazide photosensitive substances and novolac-type phenols as described in JP-A-50-125806.
A positive PS plate having a photosensitive layer made of a mixture with a resin is included.

Further, a PS plate having a photosensitive layer composed of a photocrosslinkable photopolymer as described in US Pat. No. 3,860,426, US Pat. Nos. 4,072,527 and 4 are used. PS plates having a photosensitive layer composed of a photopolymerizable photopolymer as described in JP-B No. 1,072,528, described in British Patent Nos. 1,235,281 and 1,495,861. PS plates having a photosensitive layer made of a mixture of such an azide and a water-soluble polymer are also known and can be used for these.

As an electrophotographic lithographic printing plate, a printing plate having a photoconductive layer composed of an organic photoconductor described in JP-B-37-17162 and a polymer substance containing an alkali-soluble group (acid or acid anhydride group) is disclosed. A printing plate having a photoconductive layer containing a low-molecular-weight alkali-soluble organic photoconductor described in JP-B-38-6961, and a vinyl acetate described in JP-B-41-2426 and a vinyl compound containing an alkali-soluble group. A printing plate having a photoconductive layer containing a copolymer, a printing plate having a photoconductive layer containing a photopolymerizable photoconductive compound described in JP-B-41-39405, JP-B-47-3.
A printing plate having a photoconductive layer containing a quinacridone pigment described in 6778 and an organic resin binder such as a phenol resin, and a phthalocyanine pigment described in JP-A-54-89801 and a hydrophilic resin. A printing plate having a photoconductive layer, a printing plate having a photoconductive layer containing a specific ratio copolymer of a vinyl group-containing carboxylic acid and a (meth) acrylic acid ester described in JP-B-2-43181, 2-
There is a printing plate having a photoconductive layer containing a styrene / maleic acid monoester copolymer described in JP-A-44065.

These photosensitive lithographic printing plates and electrophotographic lithographic printing plates were prepared before the treatment with the protective gum solution according to the present invention.
An image can be formed by a known operation. That is, the former develops the non-image area with alkali after exposure, and the latter elutes the non-image area after charging, exposure and toner development. As an exposure method, a reflection image exposure using a xenon lamp, a tungsten lamp, a fluorescent lamp or the like as a light source, a contact exposure through a transparent positive film, or a lithographic printing plate having a highly sensitive photosensitive layer or photoconductive layer Scanning exposure using laser light, a light emitting diode, or the like. 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 exposure such as laser, semiconductor laser such as GaAs / GaAlAs, InGaAsP, alexandrite laser, laser vapor source such as copper vapor laser, or light emitting diode.
It is possible to perform exposure by scanning exposure using a liquid crystal shutter and a liquid crystal shutter (including a line printer type light source using a light emitting diode array, a liquid crystal shutter array, etc.).

In the case of an electrophotographic planographic printing plate, the toner
develop. The toner developing method includes a dry developing method (cascade
The known methods include developing, magnetic brush developing, powder cloud developing) and liquid developing methods, and any of them can be used. In particular, the liquid developing method can form a toner fine image and is suitable for producing a printing plate having good reproducibility. Further, positive / positive development by positive development and negative / positive development by reversal development under application of an appropriate bias voltage are also possible. Formed toner
The image can be fixed by a known fixing method such as heat fixing, pressure fixing, solvent fixing and the like. As the toner component, a known composition having a resist property in the following alkaline processing liquid can be used.

The printing plate on which an image has been formed is treated with an alkaline processing liquid to remove non-image areas. The alkaline processing liquid that can be used in the present invention preferably contains an alkaline agent and has a buffering capacity. Conventionally, as an alkaline agent used in a photosensitive lithographic printing plate developer and an electrophotographic lithographic printing plate eluent, a general formula Si0 ₂ / M ₂ 0 (M = Li, N
a, K) represented by silicate, alkali metal hydroxide,
Examples thereof include inorganic alkali agents such as alkali metal and ammonium salts of phosphoric acid and carbonic acid, organic alkali agents such as ethanolamines, ethylenediamine, propanediamines, triethylenetetramine and morpholine, and mixtures thereof. Also, in order to promote the penetration of the alkaline agent into the non-image area and shorten the alkaline treatment time,
1, 2-propanol, benzyl alcohol, and an organic solvent such as alkyl cellosolve, a sulfite, or the like may be used in combination.

The alkaline treatment liquid is further described in JP-A-55-55.
Ionic compounds described in Japanese Patent No. 25100, JP-A-55-
Water-soluble cationic polymers described in JP-A-95946, water-soluble amphoteric polymer electrolytes described in JP-A-56-142528, neutral salts described in JP-A-58-75152,
Chelating agents described in JP-A-58-190952, liquid viscosity modifiers described in JP-A-1-177541, preservatives and bactericides described in JP-A-63-226657, and various surfactants. Well-known components such as natural and synthetic water-soluble polymers can be contained as necessary.

As a method for treating the printing plate on which an image is formed with the above alkaline treatment liquid, various conventionally known methods can be adopted. Specifically, a method of immersing the printing plate in the alkaline processing liquid, a method of discharging and supplying the alkaline processing liquid to the printing plate surface from a number of nozzles, and wiping the printing plate surface with a sponge or tampon containing the alkaline processing liquid, etc. Examples of the method include a method in which an alkaline treatment liquid is supplied to the printing plate surface and then spread-coated with a roll. In order to suppress the fluctuation of each printing plate to be processed, it is preferable that the process is carried out by an automatic machine while maintaining a constant liquid temperature in any method.

The printing plate thus treated on the non-image area is then rinsed with a rinse liquid. As the rinsing liquid, it is sufficient that at least it does not form insoluble matter with the dissolved components remaining in the non-image area and can be quickly removed from the printing plate surface, and a liquid having a known composition can be used. You may use it as a liquid. The printing plate that has been rinsed is coated with a protective gum solution by the processing apparatus according to the present invention while being rolled, and then dried by hot air or the like, if necessary, for printing.

[0044]

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 as long as the gist thereof is not exceeded.

Example 1 The surface of JIS 1050 aluminum sheet was grained with a rotating nylon brush using a pumice / water suspension as an abrasive. After washing with water, it was immersed in a 10% sodium hydroxide aqueous solution at 60 ° C. and etched so that the amount of aluminum dissolved was 6 g / m ² . After washing with water, it was immersed in a 30% aqueous nitric acid solution for 1 minute for neutralization, and then thoroughly washed with water. Subsequently, electrolytic surface roughening was performed in a 3% hydrochloric acid aqueous solution, and the surface was washed by immersing in a 20% sulfuric acid aqueous solution at 50 ° C. and then washed with water. Furthermore, anodizing treatment was performed in a 20% aqueous solution of sulfuric acid to form an aluminum oxide film on the surface, washed with water and dried to obtain a support. On the surface-treated surface of the support, the coating liquid for forming a photoconductive layer shown in Table 1 dispersed for 1 hour with Dynomill was applied at a solid content of 4.
After coating so as to be 4 g / m ² , it was dried at 90 ° C. for 30 seconds to obtain an electrophotographic lithographic printing plate.

[0046]

[Table 1]

The electrophotographic lithographic printing plate (printing plate No. 1) which was left at room temperature after being shielded from light and heated at 50 ° C. for 2 hours was charged in a dark place so that the surface potential of the photoconductive layer became about + 280V. After that, a semiconductor laser (780 nm) was used for scanning image exposure, and a positive charge toner (manufactured by Mitsubishi Paper Mills Ltd., LO
Inversion development (bias voltage: +12) using M-ED III
0 V), dried with cold air to remove the toner dispersion medium,
Further, it was heat-fixed to form a toner image on the photoconductive layer.
The obtained toner-developed printing plate was subjected to plate making using a planographic printing plate processing apparatus as shown below.

FIG. 1 shows a planographic printing plate processing apparatus equipped with a protective gum solution processing apparatus used in this embodiment. The basic configuration of the present processing apparatus includes an alkaline processing liquid application zone A, a solubilized non-image area removal waste zone B, a rinse processing zone C, and a cleaning solution supply means for cleaning the protective gum solution supply section. The protective gum solution coating zone D consists of four zones. The planographic printing plate is inserted into the printing plate transport line 1 in the direction of the arrow so that it is nipped by the roll and automatically transported. .

The alkaline processing liquid coating zone A is further provided with an alkaline processing liquid supply pipe 27, a straightening plate 28, and a liquid supply roller.
It is composed of an alkaline processing liquid supply unit composed of the roll 11a and an alkaline processing liquid measuring unit composed of the liquid measuring tool 47 and its guide roll 13. The planographic printing plate carried in is supplied with the alkaline processing liquid in the alkaline processing liquid supply unit, and is constantly metered in the alkaline processing liquid measuring unit. The measured alkaline treatment liquid flows on the liquid guide plate 75 installed above the circulating alkaline treatment liquid storage tank 3 and is circulated through the liquid drop hole 78 into the circulating alkaline treatment liquid storage tank 3.
Will be collected. In addition, the amount equivalent to the amount of the alkaline treatment liquid brought out in the liquid measuring unit is obtained by replenishing the replenishment liquid 19 stored in the replenishment liquid storage tank 7 through the replenishment pump 94, the pipe 122, and the replenishment liquid supply pipe 54. It is replenished from above the measuring tool 47 to wet and wash the liquid measuring tool 47, and at the same time, it is mixed in the circulating alkaline treatment liquid.

The solubilized non-image part removal waste zone B is
A solubilized non-image area removing section including a scraping blade 22, a guide roller 20, and a guide roller cleaning blade 23,
A cleaning / removal liquid supply unit including a liquid supply nozzle 52 and a nozzle scanning unit 55, which supplies the circulating rinse liquid 36 in use while scanning along the scraping portion of the scraping blade 22, and a removal waste liquid primary storage tank 4 Composed of. Scraping blade 2
The circulating rinse liquid 36 is supplied to the nozzle 2 by operating the liquid feed pump 95 by the cleaning / removing liquid supply control means (not shown) and opening the electromagnetic valve 101, and at the same time the nozzle scanning means 55 is operated. The liquid material scraped off by the scraping blade 22 and the cleaning waste liquid used for cleaning the scraping blade 22 are temporarily stored in the removal waste liquid primary storage tank 4 and then removed via the pipe 114. Waste liquid secondary storage tank 21
It is supposed to be discarded at.

The rinse treatment zone C is used for the rinse liquid storage tank 5
The circulating rinse liquid 36 stored in the pump is independently pumped up to the two rinse liquid supply pipes 37 and 38 to directly supply the circulating rinse liquid 36 to the printing plate surface, and the carrier roll pair 3
1 and 32 are arranged in parallel with each other, and are composed of an unused rinse liquid supply section for supplying an unused rinse liquid (not shown) together with compressed air from a high pressure spray gun 33. Circulating rinse 36
Is supplied during the rotation of the roll, and the unused rinsing liquid is held by the unused rinsing liquid supply control means (not shown) so that the leading portion of the planographic printing plate is sandwiched between the pair of conveying rolls 31. The rear end portion of the planographic printing plate is supplied only while being carried out from the pair of carrying rolls 32.

The protective gum solution coating zone D comprises a protective gum solution supply means 45, a liquid metering roll 43, a protective gum solution coating roll 40, and a backup roll 41. Cleaning liquid supply means 6 for cleaning the protective gum liquid supply section
0, a protective gum solution storage tank 8 for storing the protective gum solution 46,
It comprises a protective gum solution primary storage tank 6 for receiving an excessive protective gum solution. The cleaning liquid 49 stored in the cleaning liquid storage tank 9 is
The cleaning liquid supply control means (not shown) operates the liquid feed pump 99 and opens the electromagnetic valve 131, and the liquid is supplied to the protective gum liquid supply unit through the pipe 130. Used protective gum liquid and cleaning liquid 49 stored in the protective gum liquid primary storage tank 6
Is discharged to the secondary waste storage tank 21 by opening and closing the valves 107 and 108, supplied to the rinse solution storage tank 5 via the check valve 126, and to the protective gum solution storage tank 8. It can also be circulated.

Further, in the plate making process by the above planographic printing plate processing apparatus, the following processing liquids (processing liquids Nos. 1 to 4) were used.

[0054]

[Table 2]

[0055]

[Table 3]

[0056]

[Table 4]

[0057]

[Table 5]

In addition to the above treatment liquid, an unused alkaline treatment liquid is used as the replenishing liquid 19 for the circulating alkaline treatment liquid storage tank 3, and an unused circulating rinse liquid is used as the unused rinse liquid. Protective gum solution coating roll / liquid metering roll After the protective gum solution 46 is filled in the abutting portion, the plate speed is 1 minute /
The plate was continuously made for 50 plates. Further, the valve 108 is closed and the valve 107 is opened so that the excess protective gum solution is discharged to the removed waste liquid secondary storage tank 21 without being recycled and reused.

Protective gum solution treating device For cleaning the protective gum solution coating zone D, after the final plate has passed through the protective gum solution coating roll 40 / backup roll 41 pair, supply of each processing liquid is stopped,
After 5 minutes while rotating the roll group, the cleaning solution 49 was supplied at 8 ml / sec for 5 seconds, and further 1 minute later, the cleaning solution was supplied again. Further, the cleaning of the scraping blade 22 to which the solubilized photoconductive layer component is adhered is performed by stopping the supply of each processing liquid and simultaneously supplying the circulating rinse liquid 36 while scanning for 15 seconds. Was washed.

After stopping the continuous plate-making and cleaning liquid cleaning after-treatment device, the protective gum liquid coating roll, liquid measuring roll, and backup roll were waited for three rolls to dry, and then the roll surface was rolled. As a result, the protective gum solution was not fixed, and the protective gum solution was restarted, but the roll rotated without any problem, and the smooth processing of the protective gum solution could be performed. Further, the plate was washed continuously for 1 month under the above-mentioned conditions, but the rotation of the protective gum liquid component adhered to the rolls at one time caused a poor rotation, and of course the gap between the rolls of the protective gum liquid component dried and fixed to the liquid measuring roll. Insufficient feeding of the protective gum solution caused by the disproportionation did not occur.

On the first day, the fifth day, the tenth day, the twenty-third day, and the thirtieth day, the first edition after the start-up (if solid matter is attached to the roll, the most adverse effect is exhibited. Expected)
The plate-making protective gum solution-coated lithographic printing plate of No. 3 was printed on an offset printing machine (Ryobi 3200MCD). There is no difference in the number of defective prints, which is about 10 in any plate, until the printed ink is removed and clear prints are obtained, and the protective gum solution covers the entire surface of the lithographic printing plate even when making a large number of plates. It was possible to coat uniformly, to give excellent oil sensitivity in the image area and insensitivity to the non-image area, and it was possible to carry out plate making with substantially no process variation.

Comparative Example 1 Using the same lithographic printing plate processing apparatus and processing solution as in Example 1, after continuously making 50 plates, the protective gum solution coating zone D was used in Example 1 without supplying the cleaning solution 49. -The machine was stopped after rotating the roll for the time required for cleaning the roll. When it was started again after 1 hour, the roll immediately rotated, but the protective gum solution component adhered to all the rolls of the protective gum solution coating zone in a streak shape before returning to smooth rotation. It took several minutes after supplying the protective gum solution. When the rolls were left overnight and started the next day, the rolls stuck to each other and the rolls did not rotate immediately after the start. Further, a protective gum solution coating roll is formed by the protective gum solution components which are non-uniformly adhered to the liquid measuring roll.
The gap between the roll and the liquid metering roll changes, the measured amount of the protective gum liquid fluctuates with the rotation cycle, and the planographic printing plate width direction (direction perpendicular to the transport direction) also shakes. The protective gum film was uneven on the plate surface.

When the lithographic printing plate prepared as described above was extracted every other day and printed in the same manner as in Example 1, the lithographic printing plate which had been plate-formed after at least the fifth day was printed due to defective coverage with the protective gum solution. Ground stains have occurred. On the contrary, since the protective gum covers a considerable thickness in some parts, the number of defective prints is 100 before the printing ink attached to the non-image area is completely removed and a clear printed matter is obtained in the initial stage of printing.
In some cases, the number of sheets was exceeded, and the oil sensitivity in the image area and the oil insensitivity in the non-image area were poor, and the processing variation was too large to be suitable for multi-plate making.

Example 2 Only the cleaning solution in the processing solution (processing solution No. 4) used in Example 1 was replaced with the solution shown in Table 6 (processing solution No. 5), and further, Example 1
The valve 107 was closed in the planographic printing plate processing apparatus used in (1). (Thus, the excess protective gum solution and cleaning solution are temporarily stored in the protective gum solution primary storage tank 6, but the pipe 124
And, a plate-making process was carried out in the same manner as in Example 1 except that a fixed amount of the solution came to flow into the circulating rinse solution via the check valve 126.

[0065]

[Table 6]

As a result, similar to the first embodiment, the rotation failure at the time of start-up due to the sticking of the rolls did not cause the defective supply of the protective gum solution, and the protection of the planographic printing plate was prevented. Not only printing ground stains due to defective coating with gum solution, but about 10 defective print sheets until clear printed matter is obtained, and even in the case of making a large number of plates, the protective gum solution can uniformly cover the entire surface of the lithographic printing plate, which is excellent. Further, by imparting the oil-sensitive property of the image area and the oil-insensitive property of the non-image area, it was possible to carry out plate making with substantially no process variation.
Further, since the protective gum solution and the cleaning solution are weakly acidic, the pH rise of the circulating rinse solution mixed with them becomes slow,
The waste liquid from the protective gum solution coating zone could be effectively used.

Example 3 The surface of JIS 1050 aluminum sheet was grained with a rotating nylon brush using a pumice / water suspension as an abrasive. After washing with water, it was immersed in a 10% sodium hydroxide aqueous solution at 60 ° C. and etched so that the amount of aluminum dissolved was 6 g / m ² . After washing with water, it was immersed in a 30% aqueous nitric acid solution for 1 minute for neutralization, and then thoroughly washed with water. Subsequently, electrolytic surface roughening was performed in a 1% nitric acid aqueous solution, and the surface was washed by immersing it in a 30% sulfuric acid aqueous solution at 50 ° C. and then washed with water. Furthermore, anodizing treatment is performed in a 7% sulfuric acid aqueous solution to form an aluminum oxide film on the surface, and after washing with water, 70 ° C. and 3% sodium silicate 3%.
No. 1 aqueous solution for 1 minute for hydrophilic treatment, washing with water and drying to obtain a support. The surface-treated surface of the support was coated with the coating liquid for forming a photosensitive layer shown in Table 7 so that the solid coating amount was 1.7 g / m ^2, and then dried at 90 ° C. for 30 seconds to obtain a photosensitive lithographic printing plate. Obtained.

[0068]

[Table 7]

This planographic printing plate was used as NuArc FT 26V.
UDNS ULTRA-PLUS FLIP-TOP PL
Image exposure was carried out using ATE MAKER, and then plate making was carried out using the planographic printing plate processing apparatus used in Example 1 and the processing solutions (processing solutions No. 6 to 9) described below. From the suitability of the plate making process, the liquid measuring tool 47 arranged on the alkaline processing liquid coating zone A guide roll 13 of the lithographic printing plate processing device was moved to the conveying roll 17 to make the plate.

[0070]

[Table 8]

[0071]

[Table 9]

[0072]

[Table 10]

[0073]

[Table 11]

In addition to the above treatment liquid, an unused alkaline treatment liquid was used as the replenisher 19 for the circulating alkaline treatment liquid storage tank 3, and ion-exchanged water was used as the unused rinse liquid. Plate making was carried out under the same conditions as in Example 1 (excessive protective gum solution was not circulated and reused, but was discharged to the cleaning removal waste liquid secondary storage tank 21 together with the cleaned cleaning liquid).

Protective gum solution treating device For cleaning the protective gum solution coating zone D, after the final plate has passed through the protective gum solution coating roll 40 / backup roll 41 pair, the supply of each processing liquid is stopped,
The roll group was supplied with the cleaning liquid 49 at 8 ml / sec for 5 seconds after 2 minutes while being rotated, and again after 1 minute. Further, the cleaning of the scraping blade 22 to which the solubilized photosensitive layer component is adhered is performed by stopping the supply of each processing liquid and simultaneously supplying the circulating rinse liquid 36 while scanning for 10 seconds to remove the scraping blade. Washed.

After stopping the continuous plate-making and cleaning liquid cleaning post-treatment device, the protective gum liquid coating roll, liquid measuring roll, and backup roll were waited for drying, and the roll surface As a result, the protective gum solution was not fixed, and the protective gum solution was restarted, but the roll rotated without any problem, and the smooth processing of the protective gum solution could be performed. Further, the plate was washed continuously for 1 month under the same conditions, but like Example 1, the rotation failure at the time of start-up due to the sticking of the rolls to each other and of course the roll of the protective gum liquid component dried and stuck to the liquid measuring roll. The protective gum solution feeding failure caused by the disproportionation of the gap did not occur.

Further, when the planographic printing plate coated with the plate-making protective gum solution of the first plate after starting on the 1st, 5th, 10th, 20th, and 30th days was printed, 5 plates were obtained. Co-protective gum solution Not only printing stains due to defective coating, but the number of defective prints is about 15 regardless of which plate is used to get clear printed matter by removing the printing ink attached to the non-image area at the beginning of printing. Even when a large number of plates are not seen, the protective gum solution can evenly cover the entire surface of the lithographic printing plate, giving excellent image-sensitive and non-image-sensitive oil-sensing properties and substantially no process variation. Was able to do.

Comparative Example 2 In the planographic printing plate processing apparatus used in Example 1, the valve 10 was used.
7 is closed and the valve 108 is opened so that the excess protective gum solution and the washed cleaning solution are allowed to flow into the protective gum solution storage tank 8 for circulation and reuse, and not to be discharged to the removal waste liquid secondary storage tank 21. Other than that, plate making was carried out under the same conditions as in Example 1.

As a result, similar to the first embodiment, the rotation failure at the time of starting due to the sticking of the rolls to each other and, of course, the disproportionation of the gap between the rolls of the protective gum liquid component dried and stuck to the liquid measuring roll is caused. Although no defective supply of the protective gum solution did not occur, when a lithographic printing plate coated with the plate-making protective gum solution was printed at least on the 20th day or later, the printing ink adhering to the non-image area was removed at the initial stage of printing and a clear printed matter was obtained. The number of defective prints before obtaining the value was about 10 in any plate, and the protective gum solution could evenly cover the entire surface of the planographic printing plate even in the case of making a large number of plates, and showed excellent oil sensitivity in the image area. However, the protective gum solution for circulation was mixed with the washing solution and diluted, and the print background stain was generated in the non-image area, and the protective gum solution had to be replaced.

[0080]

As described above, according to the method for treating a protective gum solution of the present invention, various kinds of sticking to rolls and adhesion between rolls due to changes over time such as concentration and drying of the protective gum solution are brought about. It becomes possible to uniformly supply the protective gum solution for a long period of time and to perform the coating process by preventing the above problem. Also, by supplementing the rinse liquid with the excess protective gum solution and the cleaning liquid, practically no waste liquid is produced in the protective gum solution treatment step, and not only these solutions can be reused but also the effect of the rinse solution is prolonged. Excellent effect can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic vertical cross-sectional configuration diagram showing a planographic printing plate processing apparatus including a protective gum solution coating processing apparatus to which the present invention is applied.

[Explanation of symbols]

 A Alkaline treatment liquid coating zone B Solubilized non-image area removal waste zone C Rinsing treatment zone D Protective gum solution coating zone 1 Lithographic printing plate 8 Protective gum solution storage tank 9 Cleaning solution storage tank 40 Protective gum solution coating roll 41 Backup roll 43 Liquid measuring roll 45 Protective gum solution supply means 46 Protective gum solution 49 Cleaning solution 60 Cleaning solution supply means

Claims (2)

[Claims] 1. A processing apparatus for applying a protective gum solution while roll-conveying a planographic printing plate, in which a non-image area is dissolved and removed with an alkaline processing solution, and then a plate surface is rinsed with a rinse solution. , A protective gum solution coating roll for transporting the planographic printing plate and applying and spreading the protective gum solution on the plate surface,
A liquid measuring roll, which is in front of the roll in the plate conveying direction and contacts a part of the outer periphery of the roll to limit the amount of the protective gum liquid applied to the planographic printing plate, and a protective gum liquid coating roll. Lithographic printing by a protective gum solution treating device having a protective gum solution supplying means for supplying a protective gum solution to a contact portion with a liquid measuring roll and a cleaning solution supplying means for supplying a cleaning solution to the corresponding contact portion for cleaning. After the plate is treated with a protective gum solution, the cleaning solution is supplied by the cleaning solution supply means.
A method for treating a protective gum solution, which comprises supplying a cleaning solution to a roll group and removing and discarding the protective gum solution remaining on the roll. 2. The method for treating a protective gum solution according to claim 1, wherein the rinse solution is replenished with a cleaning solution containing a protective gum solution discarded by roll cleaning.