JPH04318553A - Processing method for planographic printing plate - Google Patents

Abstract

PURPOSE:To provide the processing method which does not stain the washing hot water for removing residual emulsion films and does not entail the putrefaction thereof in the processing method for a mono sheet type planographic printing plate of a DTR system using aluminum as a base. CONSTITUTION:A release sheet, such as paper or film, is brought into tight contact with the surface of an emulsion film during or after diffusion transfer development and thereafter, the emulsion film 3 is removed together with the release sheet 2, by which the planographic printing plate is produced. The processing method which eliminates need for using the washing hot water in removing the residual emulsion films, is simplified in processing and has no possibility of polluting the environment is thus established.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for processing lithographic printing plates using a silver complex diffusion transfer method.

0002

[Prior Art] Lithographic printing plates using the silver complex diffusion transfer method (DTR method) are described in "Photographic Silver" by Andre Lott and Edith Weide, published by Focal Press, London and New York (1972). Some examples are described in "Halide Diffusion Processes", pages 101 to 130.

As stated therein, lithographic printing plates using the DTR method include a two-sheet type in which the transfer material and image-receiving material are separate, or a two-sheet type in which the transfer material and image-receiving material are separate, or a plate in which they are provided on a single support. Two sheet types are known. Regarding the two-sheet type lithographic printing plate, JP-A-57
It is described in detail in the publication No.-158844. Further, the monosheet type is described in detail in Japanese Patent Publications Nos. 48-30562, 51-15765, 51-111103, and 52-150105.

On the other hand, paper, film, or metal such as aluminum is used as a support for lithographic printing plates. As the paper support, a paper support coated on one or both sides with an α-olefin polymer, such as polyethylene, can be used.

[0005] With lithographic printing plates using paper as a support, it is difficult to print with high quality, including printing durability, due to plate elongation and water penetration during printing. Film supports are used to overcome these problems and improve printing performance. For example, cellulose acetate film, polyvinyl acetal film, polystyrene film, polypropylene film, polyethylene terephthalate film, or a composite film in which polyester, polypropylene, or polystyrene film is coated with polyethylene film, etc. can be used as the support.

However, although lithographic printing plates using film as a support have been improved in terms of plate elongation and water absorption compared to paper-based printing plates, printing durability, water retention, and even printing Problems remain in terms of ease of applying the plate to the machine, etc.

In order to solve the various problems of the above-mentioned lithographic printing plates using paper or film as a support, a silver salt type lithographic printing plate using a metal, especially aluminum, as a support is known. JP-A No. 57-118244, No. 5
It is described in detail in various publications such as No. 7-158844 and No. 63-260491.

JP-A No. 63-260491 discloses a monosheet type DTR method in which aluminum is used as a support, a physical development nucleus layer is provided thereon, and a photosensitive silver halide emulsion layer is further provided thereon. A lithographic printing plate using the lithographic printing plate is described in detail. According to this, after the lithographic printing plate is imagewise exposed and subjected to diffusion transfer development, the residual emulsion coating is removed by washing in warm water to produce a printing plate.

[0009]

[Problems to be Solved by the Invention] The present inventors have investigated various processing methods for the mono-sheet type DTR type lithographic printing plate using aluminum as a support described in the above patent, and have found the following problems. I found it. That is, when the residual emulsion coating is removed by washing in hot water, the washing hot water becomes very contaminated with the removed emulsion, and sometimes the gelatin contained in the emulsion may rot the film. The large amount of dirt and putrefaction in the hot washing water is a major problem that makes it difficult to treat waste liquid and leads to environmental pollution.

An object of the present invention is to solve the above-mentioned problems, simplify the processing after diffusion transfer development, and provide a processing method that does not involve the risk of environmental pollution.

[0011]

[Means for Solving the Problems] The above object of the present invention is to use a roughened and/or anodized aluminum substrate as a support, provide a physical development nucleus layer thereon, and further provide a photosensitive halogen layer thereon. This is achieved by removing the emulsion layer using a release sheet after silver complex diffusion transfer development in a monosheet type lithographic printing plate provided with a silveride emulsion layer.

A method for removing an emulsion layer using a release sheet will be explained with reference to the drawings. After the lithographic printing plate is imagewise exposed as shown in FIG. 1, a release sheet 2 is brought into close contact with the emulsion layer 3 during or after development. Thereafter, as shown in FIG. 2, the emulsion layer 3 is removed along with the release sheet 2 to produce a lithographic printing plate on which a diffusion-transferred silver image is formed. Therefore, if this processing method is used, there is no need to use hot water to remove the emulsion layer 3, and the above object is achieved.

[0013] The release sheet 2 may be adhered to and peeled off by any method; for example, a roll-to-roll type release sheet 2 is used.

As the material for the release sheet 2, paper, film, etc. can be used, and of course synthetic paper etc. can also be used. Regarding the types of paper and film, the various materials described above for the support of the lithographic printing plate can be used. Further, in order to improve the adhesion and adhesion between the release sheet 2 and the emulsion layer 3, an adhesive layer such as gelatin can be provided on the release sheet 2.

[0015] The surface of the aluminum support 1 used in the lithographic printing plate of the present invention may be roughened in order to improve adhesion with the photosensitive layer provided thereon and to improve water retention. It will be done. This surface roughening treatment (so-called graining) is performed by mechanical roughening treatment such as ball graining, wire graining, brush graining, etc., or by chemically dissolving aluminum with chloride, fluoride, etc. There are chemical surface roughening treatments and electrolytic surface roughening treatments performed by electrochemically dissolving aluminum.

Although it can be used as a support for lithographic printing plates only by surface roughening treatment, it is preferable to further perform treatments such as desmutting treatment, anodizing treatment, and post-treatment as described below.

That is, by treating the roughened aluminum substrate with 10-50% hot sulfuric acid (40-60°C) or dilute alkali (sodium hydroxide, etc.), the smut attached to the surface is removed. Ru.

After the surface has been de-smutted, an anodic oxide coating is applied. Although conventionally well-known methods can be used for the anodizing treatment, sulfuric acid is used as the most useful electrolyte. Next, phosphoric acid, nitric acid, etc. are also useful electrolytes. Furthermore, JP-A-55-28
The mixture of sulfuric acid and phosphoric acid disclosed in the '400 publication is also useful.

[0019] In the sulfuric acid method, treatment is usually performed using direct current, but alternating current can also be used. The concentration of sulfuric acid is 5~
Used at 30% and 5-25 in the temperature range of 20-60℃
Electrolytic treatment is performed for 0 seconds to provide an oxide film of 1 to 10 g/m2 on the surface. Furthermore, the current density at this time is 1 to 2
0 A/dm2 is preferred. In the case of phosphoric acid method, 5 to 5
It is treated with a current density of 1-15 A/dm2 for 10-300 seconds at a concentration of 0% and a temperature of 30-60°C.

[0020] After providing the anodic oxide film in this manner, post-treatment can be performed as necessary. For example, a method of immersion treatment in an aqueous solution of polyvinylphosphonic acid disclosed in British Patent No. 1,230,447 is used. It is also possible to provide a hydrophilic polymer undercoat layer if necessary, but the choice is made depending on the properties of the photosensitive layer provided thereon.

The physical development nuclei of the physical development nucleus layer provided on the aluminum support may be known ones commonly used in the silver complex diffusion transfer method, such as colloids of gold, silver, etc., and palladium, zinc, etc. A metal sulfide obtained by mixing a water-soluble salt such as sulfide with a sulfide can be used. For details of these and their manufacturing method, techniques described in Japanese Patent Publications No. 48-30562, Japanese Patent Application Laid-open No. 49-55402, Japanese Patent Application Laid-open No. 53-21602, etc. can be used.

The photosensitive silver halide emulsion provided on the physical development nucleus layer is made of silver chloride, silver bromide, silver chlorobromide, silver iodobromide, silver chloroiodobromide, etc. produced by a conventional method. Either is fine. The silver halide emulsion is noble metal sensitized, sulfur sensitized,
Various chemical sensitizations such as reduction sensitization and sensitization that combines these can be performed, and if necessary, sensitizing dyes,
For example, spectral sensitization can be performed using dyes such as cyanine and merocyanine. Furthermore, additives such as stabilizers and surfactants may be added by known methods. For details of the photosensitive silver halide emulsion and its manufacturing method, reference may be made to the descriptions in JP-A-49-55402 and the like.

As the protective colloid for the photosensitive silver halide emulsion, various gelatins such as acid-treated gelatin, alkali-treated gelatin, gelatin derivatives, and grafted gelatin can be used, as well as polyvinylpyrrolidone, various starches, albumin, polyvinyl alcohol, It can contain hydrophilic polymer compounds such as gum arabic and hydroxyethyl cellulose.

The photosensitive silver halide emulsion layer can be directly coated on the physical development nucleus layer, but an intermediate layer such as gelatin may be provided to facilitate peelability.

The lithographic printing plate of the present invention is generally subjected to a diffusion transfer development treatment with an alkaline developer after imagewise exposure to remove the residual emulsion film, and then, if necessary, a neutralizing solution, a fixing solution, and a sensitizing solution. , plate making and printing processes such as dampening liquid are performed. The developer may be a normal photographic alkaline developer containing a developing agent such as hydroquinone, or a so-called alkaline activated developer in which the developer is contained in the material and the developer does not substantially contain a developing agent. You can use anything. In addition, some of these developers are used according to various purposes.
Compounds described in No. 486, JP-A-52-150105, etc. are added.

The compositions of the neutralizing liquid, fixing liquid, sensitizing liquid, moisturizing liquid, etc. used in the present invention may be those known to those skilled in the art depending on the purpose.

[0027]

[Examples] The present invention will be explained below with reference to Examples.
Of course, the present invention is not limited to this.

Example 1 An aluminum substrate with a thickness of 0.29 mm was roughened in a 2.5% hydrochloric acid bath by passing an alternating current of 20 A/dm2 for 1 minute, and then roughened in a 20% sulfuric acid bath. Then, anodic oxidation treatment was performed for 5 minutes with a direct current of 2 A/dm2.

A silver sol prepared by the Carey Lea method was coated onto the pretreated aluminum support so that the amount of silver was 10 mg/m 2 .

Furthermore, an ortho-sensitized silver chloride emulsion was added in an amount of silver of 1.5 g/m2 and an amount of gelatin of 1.0 g/m2.
It was coated so that it was m2.

[0031] The lithographic printing plate (3
0 cm
Diffusion transfer development was performed at ℃ for 30 seconds. Developer: Sodium sulfite 50g/l Hydroquinone 12g/l Phenidone B
6g/l Sodium hydroxide 12g/
l Sodium thiosulfate 10g/l Potassium bromide 1g/lpH 1
3.0 Phenidone B = 4-methyl-1-phenyl-3-pyrazolidone

The lithographic printing plate thus obtained was immediately coated with polyethylene terephthalate (PET) with a thickness of 150 μm and a gelatin layer of 1 g/m2 was provided as a release sheet.
) The film was brought into close contact with the emulsion layer and laminated via pinch rolls. Thereafter, when the PET film sheet was gradually peeled off, the emulsion layer was also peeled off cleanly, and a lithographic printing plate on which a diffusion-transferred silver image was formed was prepared.

Example 2 A similar lithographic printing plate was obtained by following exactly the same procedure as in Example 1, except for using polyethylene coated paper (RC paper) coated with a gelatin layer of 1 g/m2 as a release sheet. was completed.

Example 3 The lithographic printing plate prepared in Example 1 was treated with Agfa (Agfa).
) Copy Rapid Fixer (Fixer) was used to process the plate, and then printed using an offset printing machine.
It showed good ink receptivity and printing durability.

Comparative Example 1 An image formed and developed in the same manner as in Example 1 was washed in 20 liters of warm water to remove the residual emulsion film and dried at room temperature. When the hot washing water was observed, it was found that it was considerably contaminated by the removed emulsion.

Comparative Example 2 When the development and emulsion removal treatments in Comparative Example 1 were carried out on 20 lithographic printing plates (30 cm x 40 cm) using the same hot water, the hot washing water showed significant staining. When the hot washing water was left at room temperature for 10 days, rot occurred.

[0037]

According to the present invention, it is no longer necessary to use hot water to remove the residual emulsion film after diffusion transfer development, simplifying the processing, and establishing a processing method that does not involve the risk of environmental pollution.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a release sheet in close contact with an emulsion layer.

FIG. 2 is a schematic diagram showing the state of peeling of an emulsion layer.

[Explanation of symbols]

1 Aluminum support 2 Release sheet 3 Silver halide emulsion layer 4 Physical development nucleus layer

Claims (1)

[Claims] Claim 1: A mono-sheet type film using a roughened and/or anodized aluminum substrate as a support, on which a physical development nucleus layer is provided, and further on which a photosensitive silver halide emulsion layer is provided. A processing method in which the emulsion layer of a lithographic printing plate is removed using a release sheet after silver complex diffusion transfer development.