JPS59220398A - Treatment of photosensitive planographic printing plate - Google Patents

Abstract

PURPOSE:To inexpensively produce a printing plate through a simplified step, by a method wherein an erasing liquid is applied to a needless image part of a photosensitive planographic printing plate exposed imagewise to light, followed by developing and gumming, without washing the plate with water. CONSTITUTION:Either a mixed solution comprising a base-soluble acidic substance (e.g., phosphoric acid or hydrofluoric acid), a water-soluble solvent (e.g., gamma-butyrolactone) and water or an emulsified or dispersed liquid comprising a base-soluble acidic substance, a water-insoluble solvent (e.g., cyclohexane) and water, is used as an erasing liquid (having a viscoity of not higher than 200cp). Namely, a photosensitive planographic printing plate (e.g., FPD, produced by Fuji Photo Film Co., Ltd.) is exposed imagewise to light, and then the erasing liquid is applied to a needless image part detected by inspecting a printed image. Subsequently, without washing the plate with water, the plate is subjected to a developing treatment and a gumming treatment to make the printing plate (preferably, by using an automatic developing machine having both a developing part and a gumming part).

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a photosensitive planographic printing plate (hereinafter referred to as 28th plate).
It relates to a processing method for the 28th plate, which is characterized in that after the 28th plate is imagewise exposed, unnecessary image areas are coated with an erasing liquid, then developed with a developer, and then gummy treatment is performed. This relates to a processing method.

Conventional) - When processing an 8th plate, especially a positive PS plate, it is exposed by overlapping it with the film original image, and then developed with a developer 1.
Next, after washing with water, apply erasing liquid to unnecessary image areas (such as dust on the film or glass of the printing frame, film edges, register marks, etc.), wash with water, and then apply gum before printing. I was doing it.

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, Japanese Unexamined Patent Application Publication No. 5-II-1r002 discloses a plate-making method in which an fcPs plate that has been imagewise exposed is developed and immediately gummed without washing with water. Furthermore, % Kaisho! J-1/10 Hiroj Publication discloses that an image-exposed PS plate is developed 1/, immediately treated with an aqueous solution containing a surfactant without washing with water, then coated with an erasing solution 7, washed with water, and then A plate-making method in which 4 gums are drawn is disclosed.

However, even with this system, when erasing is required, the steps of applying erasing liquid, washing with water, and gumming are required after the rinsing process. Ta.

Therefore, an object of the present invention is to provide a PS plate processing method that further simplifies the plate-making process and saves cost and labor.

As a result of various studies, the inventor of the present invention found that after the image 'B original 17 was formed on the PS plate, an erasing liquid was applied to unnecessary image areas 7, and after that, development with a developer and gumming process were performed. I7 found that the above objective could be achieved.

Conventionally, the erasing solution was used for the purpose of erasing unnecessary areas after development, and after erasing, washing with water, and then gumming was necessary. However, the present inventor decided to examine the printout image that appears after image exposure, and then treated the eraser with a developer without washing away with water, and then gummed the erased area. It has been discovered that it is possible to perform the pulling and gumming of non-image areas by the image source at the same time.

According to the present invention, especially in a system that eliminates the water washing step after development described above, the plate-making process is completed by immediately performing gumming treatment without washing with water after development, so the effect is very large. be. There is no washing with water or gumming process after removing the pick, and there is no need for a sink, gum caulk, etc.

The PS version processing method according to the present invention will be explained in detail below.

As the PS plate used in the present invention, one commercially available as a normal positive PS plate can be used, but since it is necessary to detect unnecessary image areas after exposure, discoloration or pigmentation due to exposure is necessary. It is advantageous that the concentration changes are significant. In addition, it is particularly suitable for positive type 28 plates, which inevitably have a large number of erased areas.

The 0-quinonediazide compound used as the photosensitive layer in positive type 28 plates originally has a pale yellow color and becomes colorless upon exposure, but this is very weak, so in recent years many positive type 28 plates have been used. If the image is made to show discoloration or color density changes upon exposure, it is possible to immediately detect unwanted image areas upon exposure. Specifically, Fuji Photo Film ■Crack Ps version, FPD, FPD-V, FPSXFPP, etc.
SLPXSMP manufactured by Konishi Roku Kogyo ■, Curry a/) P7S
, P3S1 Hawthorn Algraphy Co., Ltd., Alympic Polychrome Co., Ltd.'s G P j , G P s, and many others.

These plate materials are first brought into complete contact with the film and then exposed to an ultraviolet light source.

ji Unnecessary image parts (parts with dust,
Apply erasing liquid to the edges (film edges, register marks, etc.) to erase them. After erasing, development is carried out with a developer without removing the erasing solution or after washing with water if necessary.

The developer is usually a developer commercially available as a developer for positive PS plates, or sodium silicate, potassium silicate, sodium hydroxide, potassium hydroxide, lithium hydroxide, tribasic sodium phosphate, dibasic sodium phosphate, Aqueous solutions of inorganic alkaline agents such as tertiary ammonium phosphate, ammonium diphosphate, sodium metasilicate, sodium bicarbonate, aqueous ammonia, and organic alkaline agents such as monoethanolamine or jetanolamine can be used.

The developing method may be an ordinary automatic developing machine having both a developing and gum section and a water washing section, a dish developing method, or a manual developing method.
In order to fully utilize the effects of the present invention, the best method is to perform direct development without removing the erasing liquid using an automatic developing machine, especially a developing machine that has both a developing and a gum section, and to remove the erasing liquid using the developing solution. .

It has been found that when a commercially available erasing fluid is used as a correction fluid for normal positive Ps plates, it has the following drawbacks.

That is, when the erasing liquid is passed through an automatic developing machine without being removed, the erasing liquid is compressed and spread by the first roller of the automatic developing machine, 5J4. It has been found that poor development occurs especially at the rear of the erased portion in the image direction.

Therefore, when a commercially available eraser is used, it is necessary to wash and remove the eraser with water before development.

As a result of studies, the present inventors were able to solve the problem by using an erasing liquid with a viscosity of 2000p or less. In other words, if the viscosity is 200 cp or less, the spread eraser can be easily removed with a developer, whereas if the viscosity is 200 cp or less,
Since it is difficult to remove the particles above 00 cp, it is necessary to wash them off with water before development.

One of the erasing fluids in the present invention contains an alkali-soluble acidic substance and is composed of a water-soluble solvent, and the other one contains an alkali-soluble acidic substance and is composed of a water-soluble A material obtained by emulsifying or dispersing an insoluble solvent in water or solubilizing it can be used.

When erasing according to the present invention, it is sufficient to dissolve the unnecessary image with a solvent and then replace it with a developer.1. If it is difficult to replace, that is, if it is made of a water-insoluble solvent, the area where the roller spreads the solvent will delay the development, resulting in poor development.Furthermore, even in the erased area, the developer-insoluble components that have been completely dissolved will be re-dissolved. Since it is easily adsorbed onto the surface of the aluminum support, it is easy to cause defective erasing. Therefore, one way to make it easier to replace the developer is to use a water-soluble solvent, and there are other methods:
) is to use an emulsified dispersion or solubilization of a water-insoluble solvent in water.

As water-soluble solvents, those that dissolve the photosensitive layer can be used, including alcohols, ketones, glycols, lactones,
Esters and others include methanol, ethanol, acetone, methyl ethyl ketone, ethylene glycol monomethyl ether, γ-butyrolactone, dimethyl formamide, and the like. It is also necessary to use water-insoluble solvents to dissolve the photosensitive layer, such as cyclohexanone, butyl acetate, and benzyl alcohol. Specifically, higher fatty acid salts, second-class higher fatty acid salts, higher alkyl dicarboxylic acid salts, primary higher alcohol sulfate ester salts, λ-class higher alcohol sulfate ester salts, primary alkyl sulfonates, and second-class higher alcohol sulfate salts. Alkyl sulfonates, higher alkyl disulfonates, sulfated fats and fatty acid salts, sulfonated higher fatty acid salts, higher alkyl phosphate ester salts, glycerin esters of higher fatty acids, glycol esters of higher fatty acids, pentaeryths of higher fatty acids It can be emulsified and dispersed or solubilized with an aqueous solution of liter ester, sucrose ester of higher fatty acid, sorbitan and mannitan ester fxE of higher fatty acid. Solvents insoluble in water include water/surfactant/
It is preferable that the total weight of the solvent is 7% by weight, and the surfactant is 50% by weight.

Preferably, the erasing liquid further contains an alkali-soluble acidic substance. In other words, even if water-soluble solvents such as ethylene glycol monomethyl ether and r-butyrolactone are used alone, the ink will be erased in some cases, but sometimes the ink will come up during printing even if it appears to have been erased. A situation arises. This is because the solvent alone is not yet able to prevent re-adsorption onto the aluminum support. We have discovered that by dissolving an alkali-soluble acidic substance in this material, re-adsorption onto the surface of the aluminum support can be prevented and complete erasure can be achieved. Examples of alkali-soluble acidic substances include inorganic acids such as phosphoric acid, sulfuric acid, nitric acid, and hydrofluoric acid, p) organic acids such as luenesulfonic acid, acetic acid, trichloroacetic acid, and organic phosphonic acids, and carboxylic acids, sulfonic acids, and phosphonic acids. Organic polymers containing acids, such as polyacrylic acid, phosphoric acid, and hydrofluoric acid are particularly preferred.

These solvents, surfactants, and acidic substances may be used alone or in combination.
It can be used in combination with aI or more, and if necessary, various compounds and dispersants can be added, dissolved, and dispersed. Examples include dyes and pigments for coloring purposes, surfactants for coatability on plates and prevention of spreading, polymeric compounds, fine particles such as silicon dioxide, and the like.

Such an erasing liquid can be applied onto the plate with a brush or brush, or with an erasing pen or the like. Further, it may be removed by washing with water before development, or may be removed at the same time as development without being removed.

The plate material developed as described above can be made into a printing plate by camming after washing with water or by gumming immediately after development. Commercially available gum liquid can be used, but as the gum liquid after washing with water, for example, GPS manufactured by Fuji Photo Film ■ can be used.
It can be coated with GU, GU-co, etc., and can be gummed with a gum coater or by hand coating. Further, the gum used in the method of gumming immediately after development can be processed using the company's FP Kaashi, an automatic developing machine that does not require a water washing step.

Next, the present invention will be explained in more detail with reference to Examples.

Example 1 FPD'lr film manufactured by Fuji Photo Film 70 (
Exposure was made from a distance of ylH. Discoloration occurred in the non-image areas that were exposed to light, and the difference in image density was o, ij. The unnecessary image area of this plate was erased with the following erasing liquid, and without washing with water, the unnecessary image area was erased using the same company's tooEyc developer
A developing and camming process was carried out by adding Gum FP (diluted to 6 parts with water) and Gum FP (diluted to 1 part with water).

1) γ-Butyrolactone TA10I water
6I phosphoric acid (5%) Polyester II)/tyrene glycol monomethyl ether yog water
6! ? Phosphoric acid (fj%
) gIIf) r-butyrolactone ioogshiIV) f-tylene glycol monomethyl ether / 00ji □V
) Cyclohexanone / 00gVl)R
P-/ (manufactured by Fuji Photo Film ■) Viscosity: approx. 30.0θOCp ■) RP-2 (manufactured by Fuji Photo Film ■) Viscosity: approximately -'4,000 cp ■) γ-Butyrolactone 6gg Metrose) Is-2/g (Shin-Etsu Chemical) (Hydroxypropylated methylcellulose manufactured by ■) Zorulonic, B'-toe isg (nonionic surfactant manufactured by Kakika ■) Water sg phosphoric acid 611 Aerosil #3zaQ Ig (silicon dioxide fine powder manufactured by Nippon Aerosil ■) Viscosity approx. The viscosity was 6 sills m as measured by a B-type viscometer at 2J0C, and I) to ■) had a very low viscosity.

When these plates were printed and evaluated using a printing machine, the following results were obtained.

Note that the erasability of unnecessary image areas in the table is the number of areas that are defective in erasing when 10 areas are erased.

Both of the erasing liquids/l1lJ and B) in the present invention gave excellent results in terms of erasing properties and developability.

However, when using only water-soluble solvents l) and IV) and water-insoluble solvent V), poor erasure occurs, and even though it appears to have disappeared, the ink comes up during printing. In addition, the conventional erasing liquid VIA (2) and the one with a viscosity of 200 cp or more (2) had good erasability, but the developability deteriorated and stains were generated at the rear of the erased area (2).

Example 2 An erasing solution (2) was prepared by emulsifying and dispersing the following composition and was processed in the same manner as in Example 1, and both erasability and developability were good.

■ Cyclohexanone 56g Perex NBL 3og (Kao Atlas ■
aqueous solution of sodium alkylnaphthalene sulfonate) water iogrin e (rs %) μI Example 3 Development was carried out using plate development using the erasing solution I) of Example 1, followed by washing with water and gum arabic subtraction, followed by printing. Good results were obtained for C.

Example 4 After erasing using the erasing solution II) of Example 1 and washing with water, it was developed using Fuji Photo Film's developer DP-J diluted 7 times with water using Fuji Photo Film's OOU. After rinsing with water, a cam solution prepared by diluting the company's positive gum GP with 1:1 water was applied using a cam coater = 0100 made by the same company, and after drying, printing was performed, and very good results were obtained.

Example 5 Good results were obtained when processing was carried out in the same manner as in Example 1 using erasing liquid X) or M) having the following composition.

Engineering X)? tyrene glycol monomethyl ether tO9 water itrg hydrofluoric acid (170%) 29XI) γ
-butyrolactone trsg water
/39 Hydrofluoric acid (gO
%) 29 Patent Applicant Fuji Photo Film Co., Ltd. Procedural Amendments Dear Commissioner of the Patent Office 1, Case Description Showa SR Year Patent Application No. 21271
No. 2, Title of the invention Processing method for photosensitive lithographic printing plate 3,
Relationship with the case of the person making the amendment Patent applicant Location 210-4 Nakanuma, Minamiashigara City, Kanagawa Prefecture Number of inventions increased by the amendment 1 5. Subject of the amendment The “Scope of Claims” column of the specification and “Details of the Invention” "Explanation" column 6, Contents of amendment (1) The scope of claims column is amended as shown in the attached sheet.

(2) Page 2, line j After “next” “More if necessary.” Insert.

(3) 3rd Sada lμ line Delete "-gum pull".

(4) 3rd line on page 3 After “next” "As necessary" Insert.

Attachment 2, Claims 1 A photosensitive method characterized in that after imagewise exposing a photosensitive lithographic printing plate, an erasing liquid is applied to unnecessary areas, followed by development with a developer, and then gumming. How to process lithographic printing plates.

(e) The processing method according to claim 1, wherein the photosensitive lithographic printing plate is a positive-working photosensitive lithographic printing plate.

3. The processing method according to claim 1, wherein the erasing liquid has a viscosity of 00 cp or less.

μ Claim 3, characterized in that the erasing liquid contains an alkaline acidic substance and is composed of a water-soluble solvent.
Treatment method described in section.

j. The processing method according to claim 3, wherein the erasing liquid contains an alkali-soluble acidic substance and is made by emulsifying or dispersing or solubilizing a water-insoluble solvent in water.

Apply erasing liquid to the important image areas, then use the buoyancy method with eraser.

Claims (1)

[Scope of Claims] l A photosensitive lithographic printing plate characterized in that after imagewise exposing a photosensitive lithographic printing plate, unnecessary image areas are coated with an erasing solution, then developed with a developer, and then gummed. How printing plates are processed. (e) The processing method according to claim 7, wherein the photosensitive lithographic printing plate is a positive-working photosensitive lithographic printing plate. J. The processing method according to claim 1, wherein the viscosity of the erasing liquid is 2θθcp or less. ≠ The erasing liquid contains an alkali-soluble acidic substance and is a water-soluble solvent! 7. The processing method according to claim 3, wherein the tW characteristic is 7. j. The processing method according to claim 3, wherein the erasing liquid contains an alkali-soluble acidic substance and is made by emulsifying or dispersing or solubilizing a water-insoluble solvent in water.