JPH0526678B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a plate-making method using a photosensitive lithographic printing plate (hereinafter referred to as PS plate),
More specifically, it relates to a plate-making method in which a PS plate is sequentially image-exposed, developed, and gummed, then unnecessary image areas are erased with an erasing liquid, and after washing with water, it can be used for printing without gumming. be. Conventionally, when creating a lithographic printing plate using a PS plate, especially a positive PS plate, the transparent original image and the photosensitive layer of the PS plate were brought into close contact with a vacuum printing frame, and after exposure, they were developed with a developer and washed with water. Afterwards, unnecessary image parts (those due to dust on the film, film edges, register marks, etc.) are erased with an erasing liquid, washed with water, and then gummed and printed. Incidentally, in recent years, systems that omit the post-development washing step have been developed for the purpose of low cost and low pollution. For example, JP-A-54-8002 discloses a plate-making method in which an image-exposed PS plate is developed and gummed immediately without washing with water. Furthermore, JP-A No. 55-115045 discloses that the image-exposed PS plate is developed, immediately treated with an aqueous solution containing a surfactant without washing with water, and then an erasing solution is applied and washed with water.
A plate-making method is disclosed in which the paper is then gummed. However, in all of these plate-making methods, gumming must be performed as a pre-process for printing, and this has been a major obstacle to lowering the cost and reducing the performance of the plate-making process. SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a low-cost and labor-saving plate-making method that does not require gumming after erasing and washing. As a result of various studies, the present invention and others have found that after image exposure, development and gumming are performed on the PS plate, after which an erasing liquid is applied to unnecessary image areas, and then washing with water is performed. We discovered that it is possible to print without any additional steps. The plate making method according to the present invention will be explained in detail below. The PS plate used in the present invention is formed by providing a photosensitive layer on a support having a hydrophilic surface. Preferably, an aluminum plate is anodized, and then a photosensitive layer is provided on the hydrophilic support. In particular, a photosensitive layer having a positive type photosensitive layer, which inevitably has a large number of erased areas, is suitable. The aluminum plates used include pure aluminum and aluminum alloy plates. Various aluminum alloys can be used; for example, alloys of aluminum and metals such as silicon, copper, manganese, magnesium, chromium, zinc, lead, bismuth, and nickel are used. These compositions are
In addition to some iron and titanium, it also contains negligible amounts of other impurities. The aluminum plate is preferably grained, but before that, if necessary, the surface is pretreated to remove rolling oil from the surface and expose a clean aluminum surface. For the former, solvents such as trichlene, surfactants, etc. are used. For the latter, alkalis such as sodium hydroxide and potassium hydroxide can be used.
A method using an etching agent is widely used. The graining method is mechanical graining method,
Chemical graining methods and electrochemical graining methods (so-called electrolytic etching methods) are used. The grained aluminum plate is washed with water if necessary, and then chemically etched if necessary. The etching solution used is usually selected from a base or acid hydroxide solution that dissolves aluminum. In this case, the etched surface must not be coated with aluminum or a film different from aluminum derived from the etching solution components. Examples of preferred etching agents include basic substances such as sodium hydroxide, potassium hydroxide, trisodium phosphate, disodium phosphate, tripotassium phosphate, and dipotassium phosphate; acidic substances such as sulfuric acid and persulfuric acid. , phosphoric acid, hydrochloric acid and their salts. Etching is carried out by immersing the aluminum plate in the above-mentioned etching solution or applying the etching solution to the aluminum plate, and the etching amount is preferably in the range of 0.5 to 10 g/m ² . For the above-mentioned etching, it is desirable to use an aqueous base solution because of its high etching speed. In this case, since smut is generated, desmut processing is normally performed. The acids used in the desmut treatment include nitric acid, sulfuric acid, phosphoric acid, chromic acid, hydrofluoric acid, and hydrofluoric acid. The etched aluminum plate is washed with water if necessary, and then anodized. Anodic oxidation can be performed by methods conventionally practiced in this field. Specifically, when a direct or alternating current is passed through aluminum in an aqueous or non-aqueous solution containing sulfuric acid, phosphoric acid, chromic acid, oxalic acid, sulfamic acid, benzenesulfonic acid, etc. or a combination of two or more of these, aluminum supports An anodic oxide film can be formed on the body surface. The processing conditions for anodic oxidation vary depending on the electrolyte used, so they cannot be determined unconditionally, but in general, the concentration of the electrolyte is 1 to 80% by weight, and the temperature of the solution is 5 to 80%.
70℃, current density 0.5 to 60 ampere/dm ² , voltage 1
A range of ~100V and electrolysis time of 30 seconds to 50 minutes is appropriate. Among these anodizing processes, in particular, the method of anodizing at high current density in sulfuric acid used in the invention described in British Patent No. 1,412,768 and the method described in US Pat. No. 3,511,661 Preferred is the method of anodic oxidation using phosphoric acid as an electrolytic bath. The aluminum support subjected to such treatment is treated to make it hydrophilic. One preferred hydrophilic treatment is treatment with an aqueous solution containing at least one group of carboxylic acid, sulfonic acid, phosphonic acid and/or salts thereof. Specific compounds include gum arabic, carboxymethylcellulose, carboxyethylcellulose, carboxymethylhydroxyethylcellulose, alginic acid, polyacrylic acid and acrylic acid derivatives, copolymers of vinyl methyl ether and maleic anhydride, vinyl acetate and maleic anhydride, and copolymer of
Polyvinylsulfonic acid and salts thereof.
These compounds may be used in combination of two or more, and if necessary, other compounds such as water-soluble metal salts (e.g. zinc acetate) as described in US Pat. No. 3,860,426, or silica,
It may contain fine particles such as titanium dioxide or a dye for the purpose of preventing halation. After these compounds are dissolved in water, an organic solvent is added if necessary, and this is applied onto the anodic oxide film of an aluminum plate by a known method such as a dip method, a roll coating method, a bar coating method, etc., and then dried. Thereafter, if necessary, an excess amount is removed by washing with water, or by immersion in a heated aqueous solution followed by washing and drying, a thin layer composed of the above-mentioned compound is formed. The coating solution concentration is preferably about 0.001 to 1% by weight, and the coating weight after drying is about 1 to 1000 mg/m ² . Yet another preferred hydrophilic treatment is treatment with an aqueous solution of an inorganic salt. Inorganic salts include US Pat. No. 2,714,066 and US Pat.
As described in the specifications of No. 3181461, in addition to alkali metal silicates, such as sodium silicate,
Examples include fluorinated zirconate, and the weight after treatment is preferably about 1 to 100 mg/m ² . A photosensitive layer is provided on the lithographic printing plate support treated in this way, and in particular, in the practice of the present invention, a conventionally known photosensitive layer is provided as a photosensitive layer for a positive-working PS plate. It is suitable for The positive photosensitive layer is preferably made of an o-quinonediazide compound and a phenolic resin. The o-quinonediazide compound used in the present invention is a compound having at least one o-quinonediazide group, which increases its alkali solubility by irradiation with actinic light, and compounds having a wide variety of structures can be used. Regarding such o-quinonediazide compounds, see "Light-Sensitive Systems" by J. Koser, John Wiley & Sons,
Inc.) pages 339-352, which can be used in the present invention. In particular, sulfonic acid esters or sulfonamides of o-quinonediazide reacted with various aromatic polyhydroxy compounds or amines are suitable. Among the o-quinonediazide compounds used in the present invention, esters of benzoquinone (1,2)-diazide sulfonic acid chloride and polyhydroxyphenyl, such as those described in Japanese Patent Publication No. 43-28403, or naphthoquinone Most preferred are esters of -(1,2)-diazidosulfonic acid chloride and pyrogallol-acetone resin. Other suitable o-quinonediazide compounds include benzoquinone-(1,2)-diazide sulfonic acid chloride or naphthoquinone-
There are esters of (1,2)-diazide sulfonic acid chloride and phenol-formaldehyde resins. Other useful o-quinonediazide compounds are known and reported in numerous patents.
For example, JP-A-47-5303, JP-A-48-63802,
No. 63803, No. 96575, No. 96575, No. 49-
No. 38701, No. 13354, Special Publication No. 11222, No. 41-1973,
US Patent No. 45-9610, US Patent No. 17481, US Patent No. 2797213, US Patent No. 3454400, US Patent No. 3544323,
Same No. 3573917, Same No. 3674495, Same No. 3785825,
British Patent No. 1227602, British Patent No. 1251345, British Patent No.
Examples include those described in specifications such as German Patent No. 1267005, German Patent No. 1329888, German Patent No. 1330932, and German Patent No. 854890. The phenolic resin used in the present invention refers to a novolac resin and a polyvinyl compound having a phenolic hydroxyl group, and the novolac resin is one obtained by condensing phenols and formaldehyde in the presence of an acidic catalyst. Also includes those modified with xylene or mesitylene. Such novolak resins include phenol-
Representative examples include formaldehyde resin, cresol-formaldehyde resin, p-tert-butylphenol-formaldehyde resin, and phenol-modified xylene resin. Examples of the polyvinyl compound having a phenolic hydroxyl group include polyhydroxystyrene polymers and copolymers thereof, and halogenated polyhydroxystyrene polymers and copolymers. The amount of o-quinonediazide compound in the total composition is
It is 10 to 50% by weight, more preferably 20 to 40% by weight. The amount of phenolic resin blended is 45 to 79% by weight, preferably 50 to 70% by weight of the total composition.
It is. The composition of the present invention is applied onto a support after being dissolved in a solvent that dissolves each of the above components. Examples of the solvent used here include ethylene dichloride, cyclohexanone, methyl ethyl ketone, methyl cellosolve acetate, toluene, and ethyl acetate, and these solvents may be used alone or in combination. The concentration of solid content in the coating solution is 2-
50% by weight is suitable. In addition, in the case of photosensitive planographic printing plates, the coating amount is generally
A suitable amount is 0.5-3.0g/ ^m2 . The positive PS plate thus prepared is used to produce a lithographic printing plate through the following process. After the photosensitive layer of the PS plate is brought into complete contact with the original film, exposure is performed using an ultraviolet light source. The exposed positive PS plate is usually prepared using a commercially available developer for positive PS plates, or sodium silicate, potassium silicate, sodium hydroxide, potassium hydroxide, lithium hydroxide, or triphosphoric acid. Inorganic alkaline agents such as sodium, dibasic sodium phosphate, tertiary ammonium phosphate, diammonium phosphate, sodium metasilicate, sodium bicarbonate, aqueous ammonia, etc. and organic agents such as monoethanolamine or diethalamine, etc. Develop with an aqueous alkaline solution. The development may be carried out by an automatic developing machine having both a developing and gum section, a conventional automatic developing machine having a water washing section, a dish developing machine, or a manual developing machine. The developed plate material is gummed. As the gum, a commercially available gum liquid or an aqueous solution containing an organic substance having a desensitizing effect such as gum arabic, dextrinized edemarch, water-soluble cellulose, phosphoric acid, etc. can be used. Gumming can be carried out by an automatic developing machine having both a developing and a gum section, a gum coater, or manual coating using a sponge or the like. On the gummed plate material, unnecessary images such as dust, film edges, register marks, etc. are erased with an erasing liquid. As the erasing liquid, a commercially available erasing liquid can be used, and an erasing liquid containing a solvent that dissolves the image, phosphoric acid, hydrofluoric acid, or the like can be used. As for the erasing method, an erasing liquid is applied onto the unnecessary image with a brush or similarly applied with an erasing pen, and after erasing is completed, the image is washed with water. Washing can be done by showering or wiping with a damp sponge or cloth. The entire plate surface may be washed with water, or the eraser may be simply wiped off from the erased areas. A lithographic printing plate treated in this way can be printed without subsequent gumming,
Similar to the conventional method, good printed matter can be obtained without staining. Next, the present invention will be explained in more detail by giving Examples. In addition, all "%" in the following examples are weight % unless otherwise specified. Example 1 An aluminum plate (material: 1050) having a thickness of 0.3 mm was degreased by washing with Triclean, and then the surface was grained using a nylon brush and a 400 mesh pumice-water suspension, and the plate was thoroughly washed with water.
This plate was etched by immersing it in a 25% sodium hydroxide aqueous solution at 45℃ for 9 seconds, and after washing with water, it was further etched.
It was immersed in 20% nitric acid for 20 seconds and washed with water. The amount of etching on the grained surface at this time was approximately 3 g/m ² .
Next, this plate was heated at a current density of 7% sulfuric acid as an electrolyte.
After providing a DC anodic oxide film of 3 g/m ² at 15 A/dm ² , it was washed with water and dried. Next, the aluminum plate was coated with a 0.35% aqueous solution of the following hydrophilic compound using a roll coater, and then air-dried. The solid content after dry application was approximately 15 mg/m ² in each case. ) Gum arabic) Celogen 7A (carboxymethyl cellulose manufactured by Daiichi Kogyo Co., Ltd.) ) Sodium alginate) Comparative example No intermediate layer The following photosensitive solution was applied to the aluminum plate provided with these intermediate layers and dried at 100°C for 2 minutes. positive type
PS versions) to ) (Example) and ) (Comparative Example) were obtained. The coating amount after drying was 2.4 to 2.5 g/m ² in all cases. Photosensitive liquid Ester compound of naphthoquinone-1,2-diazide-5-sulfonyl chloride and pyrogallol-acetate resin (Note)...0.90g Cresol-formaldehyde resin...2.00g t-Butylphenol-formaldehyde resin (Note)...0.05g Naphthoquinone -1,2-diazide-4-sulfonic acid chloride...0.03g Oil Blue #603 (manufactured by Orient Chemical Industry Co., Ltd.)...0.03g Methyl ethyl ketone...8g 2-methoxyethyl acetate...15g Note In the specification of U.S. Patent No. 3635709, What is described in Example 1 Note: What is described in US Patent No. 4,123,279 These positive PS plates were placed in close contact with the film original for 70 cm using a 30 ampere carbon arc lamp.
exposed from a distance of Post-processing A) Example Using an automatic processor 800E manufactured by Fuji Photo Co., Ltd., the company's positive developer DP-3 was diluted with water at a ratio of 1:6 and heated at 25°C.
It was developed for 40 seconds. Further, the company's gum liquid FP was diluted 1:1 with water in the gum area, and immediately after development, gumming and drying were performed. After that, unnecessary images such as dust and film edge marks were erased by applying the same company's erasing liquid RP-1 with a brush, and then the plate was wetted with water using a tap shower. The eraser was removed by washing the plate surface with water using a sponge. Processing B) Comparative example Developed with Fuji Photo Co., Ltd.'s automatic processor 800U using the company's developer solution DP-3 (1:6) at 25°C for 40 seconds and washed with water, then removed unnecessary images with RP-1. After erasing and washing with water, gumming was performed using Gum Coater G800 manufactured by the same company by diluting Gum GP for positive plates with water at a ratio of 1:1. Treatment C) Comparative Example In treatment A), instead of FP, a rinsing liquid FR made by the same company diluted with water at a ratio of 1:7 was added to the gum part, and gumming was performed in the same manner as in post-erasing treatment B). Treatment D) Comparative Example Treatment B) or Treatment C) without gumming after erasing and washing with water. When the printing plate obtained by the above treatment was plate-made and printed several days later, the following results were obtained.

[Table] ○... Good printed matter with no stains was obtained. ×... Poor erasing in the erased area and/or stains such as fingerprints in the non-image area. In the embodiment of the present invention, the plate material))) is processed by processing A) A printing plate was obtained by carrying out this process, and a good printed matter without staining was obtained, similar to that obtained by treating the conventional plate material) with treatment B) or C). In comparison, those that were washed with water or rinsed after development required degassing after erasing. In addition, in the case (iv) without an intermediate layer, stains occurred even in the case of treatment A). Example 2 After an aluminum support was treated in the same manner as in Example 1, an aqueous solution containing 0.2% of 7A cerogen and 0.2% of zinc acetate was coated with a roll coater and dried to form an intermediate layer. The solid content after drying was approximately 20 mg/m ² . The aluminum support provided with this intermediate layer was coated with a photosensitive layer similar to that in Example 1, and then subjected to the same treatment as in Example 1 (A) and then printed, resulting in good prints without stains. Ta. Example 3 The plate material obtained in Example 2 was plate developed with DP-3 (1:6) (25°C for 1 minute), washed with water, and Gum GU manufactured by Fujifilm Corporation was diluted with water to a ratio of 1:1. After applying it to the entire surface with a sponge, I buff-dried it. After erasing this, I wiped off only the erased area with a wet cloth to wipe off the erasing liquid, and then printed, and a good result was obtained. Example 4 An aluminum support treated in the same manner as in Example 1 was immersed in a 0.2% polyvinylphosphonic acid aqueous solution at 60° C. for 4 minutes. The molecular weight of polyvinylphosphonic acid is approximately 100,000. Next, the plate was washed with water, dried, and then coated with the same photosensitive layer as in Example 1. When the same treatment as A) was carried out, good results were obtained in printing. Example 5 The surface of a JIS1050 aluminum sheet having a thickness of 0.24 mm was roughened using a rotating nylon brush using a pumice water suspension as an abrasive. The surface roughness (center line average roughness) was 0.5μ. After washing with water, it was immersed in a 10% aqueous solution of caustic soda heated to 70°C to etch the aluminum surface so that the amount of dissolved aluminum was 6 g/m ² . After washing with water, immerse in a 30% nitric acid aqueous solution for 1 minute, and use a rectangular wave alternating waveform with an anode voltage of 13 volts and a cathode voltage of 6 volts in a 0.7% nitric acid aqueous solution. Power supply waveform described in the example) Perform electrolytic roughening for 20 seconds,
After cleaning the surface by immersing it in a 50°C solution of sulfuric acid, it was washed with water. Furthermore, anodization treatment was performed using direct current in a 20% sulfuric acid aqueous solution so that the weight of the anodic oxide film was 3.0 g/m ^{2 ,} washed with water, and after drying, JIS standard No. 3 sodium silicate (SiO ₂ /Na ₂ It was immersed for 15 seconds in a 4% aqueous solution (liquid temperature: 70°C) of O = 3.1 to 3.3 (molar ratio). After washing with water and drying, the same photosensitive layer as in Example 1 was subjected to the same treatment as post-coating treatment A), and good results were obtained in printing.

Claims (1)

[Scope of Claims] 1. A photosensitive lithographic printing plate having a photosensitive layer on a support having a hydrophilic surface is sequentially imagewise exposed and developed to remove the non-image area of the photosensitive layer. A plate-making method in which a lithographic printing plate is obtained by exposing the hydrophilic surface, gumming it, applying an erasing liquid to unnecessary image areas, and finally washing with water, in which gumming is performed in the step after washing with water. A plate-making method characterized in that it does not contain 2. The plate-making method according to claim 1, wherein the support having a hydrophilic surface is an aluminum plate that is anodized and then subjected to hydrophilic treatment. 3. Plate making according to claim 2, wherein the hydrophilic treatment is treatment with an aqueous solution of a compound or inorganic salt containing a carboxylic acid group, a sulfonic acid group, a phosphonic acid group, or a salt group thereof. Method.