JPS622260A - Improved printing plate material - Google Patents

Abstract

PURPOSE:To enhance water retentivity of an offset printing plate, that is, resistance to ink stains by forming a silver halide emulsion layer and a physical development nucleus layer on a support to form the printing plate, and incorporating a specified solvent in both or either of both layers. CONSTITUTION:The printing plate is prepared by forming the silver halide emulsion layer and the physical development nucleus layer on the support, and the solvents represented by formulae [I] and/or [II] are incorporated in both or either of both layers in an amount of 1-100mg/m<2>, optimally, 30-60mg/m<2>, and if they are used above 100mg/m<2>, trouble occurs in coatability and DTR developability is deteriorated. As the silver halide emulsion layer, any silver halide composed of silver chloride, bromide, chlorobromide, or chloroiodide may be used, and as the physical development nuclei, metals, such as antimony, bismuth, and lead, and their sulfides can be used.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention improves the printing properties of an offset printing plate obtained by applying a silver complex diffusion transfer method, particularly water retention, control of stain generation, and ink receptivity. This article concerns an improved method for achieving this goal.

(B) Prior art and its problems Normally, in planographic printing, both water and ink are supplied to the plate surface, and the image area (consisting of lipophilic areas that easily accept ink) is filled with colored ink. The non-image area (consisting of a hydrophilic area that does not accept ink but receives water) selectively accepts water and metal, and the ink on the image is transferred to a substrate such as paper. done by. Therefore, in order to obtain good printed matter, the difference in oleophilicity and hydrophilicity between the surface of the image area and the background non-image area must be sufficiently large so that when water and ink are applied, the image area will receive a sufficient amount of ink. , it is necessary that the non-image areas do not receive any ink.

In general, it is well known in the industry that the water retention capacity of lithographic printing plates and the occurrence of smudges on printing plates are not caused by a single cause, but are caused by a combination of various factors. . For example, this may be due to the inherent properties of the plate material, or may be due to the printing ink, dampening water, or printing paper, or the condition of the printing press or the temperature at the time of printing. This may be due to the influence of environmental conditions such as humidity. Therefore, it is important to properly maintain these conditions and environment during printing.

However, from a practical point of view, materials are required that can be printed under as wide a range of conditions as possible.

A drawback associated with lithographic printing plates made by the silver complex diffusion transfer method (DTR method) is that they have insufficient resistance to mechanical abrasion, etc., and the hydrophobic areas that carry the ink image gradually lose their ink receptivity. In order to achieve this, the printing durability is reduced. Furthermore, the hydrophilic areas gradually become hydrophobic, so that non-image areas become more likely to be smeared with ink. Furthermore, the uniform greasy ink receptivity in the hydrophobic image area is impaired, which causes a change in ink receptivity in the image area, resulting in the printed area not being able to accept a uniform amount of ink.

Printing plates for the DTRTR method are already known in which metallic silver patterns are applied and used as all-ink receptive devices (for example, U.S. Pat. No. 3,220,337; U.S. Pat. No. 3,721.55).
No. 9, Special Publication No. 48-16725, Special Publication No. 48-30562
, JP-A-46-4422, JP-A-53-21603, etc.) Although some of them have been put into practical use, they still have the above-mentioned drawbacks.

(C1 Purpose of the Invention The purpose of the present invention is to chemically alleviate the loss of hydrophobic and hydrophilic portions caused by mechanical abrasion of a lithographic printing plate, and to improve water retention, that is, to control staining. This is done in consideration of the chemical structure, ie, physical properties, of the organic solvent.The object of the present invention is achieved as follows.

0 Constituent structure of the invention In a lithographic printing plate used as a transfer silver ink receiving part by a silver complex salt diffusion transfer method, the printing plate is...

It has a silver halide emulsion layer and a physical development nucleus layer on a support, and both layers or one layer KCI:] and/or [■
] A solvent having the general formula t-i rr? The printing plate material contains 1 to 100++v per fi.

[:I] R'0-C)12CH2OX (in the formula R1
represents an alkyl group, an aryl group, an aralkyl group, a heterocyclic residue, an alkenyl group; or X represents hydrogen or a lower acyl group. ) (II) 几2y-几3 In the formula, 几 and R may be the same or different and each represents an alkyl group or an aryl group. Y has again. Here, R4 represents a lower alkyl group.

For example, along with cyanine dyes such as sulfoanion and sulfobetaine sensitizing dyes dissolved in a solvent (water, alcohol, DMF, etc.), hydroxyl groups with a solubility in water of 10% or less at 40°C and high vapor pressure, Solvents with ester groups or keto groups (however, the total number of carbon atoms is n≧
3). The solvent used in the present invention is dissolved in this while taking into consideration the amount of the sensitizing dye that can be completely dissolved at 40° C. or higher, and the solution is added to the silver halide emulsion and adsorbed.

Furthermore, when producing the physical development nucleus layer, it can also be used together with a solvent that dissolves the development nucleus and the developing agent.

The feature of the present invention is that the water retention property of the offset printing plate, that is, the control of ink staining, can be improved by incorporating the organic solvent into the emulsion layer or the development nucleus layer, since it has both hydrophilic and lipophilic properties. be able to. Furthermore, in view of the physical properties, the amount of colloid used can be reduced, and the adsorption of the sensitizing dye to AgX can also be increased. Therefore, it has the advantage that the same sensitivity can be reproduced even if the color cumulation is reduced.

Next, specific examples of the solvent used in the present invention will be shown.

1. Ethylene glycol monoethyl ether 2. Ethylene glycol monoethyl ether 3. Ethylene glycol monophenyl ether 43 Ethylene glycol monophenyl ether 5 Selon lup acetate 6 Ethy lup tilktone 7 Imbutyl acetate 8) Thir phenyl carbinol The optimum use t of the solvent is 30 to 601- C1001
The use of 119/n1 or higher causes problems in coating properties and worsens DT developability. When the emulsion layer contains all of the solvent, it is used by adding it to a typical sensitizing dye solution as shown below. Specific examples of the dye will be shown, but the invention is not limited thereto.

As the silver halide emulsion of the lithographic printing plate of the present invention, any silver halide consisting of silver chloride, silver bromide, silver chlorobromide, silver chloroiodide, or silver chlorobromoiodide can be used, and in particular, Preferably, the silver halide has a silver chloride content of about 50 moles or more. There are no restrictions on the size, crystal habit, distribution, etc. of the silver halide grains, and any method known in the ordinary photographic field may be used for producing the silver halide emulsion. Silver halide emulsions can be sensitized by well-known chemical sensitization techniques, and can also be spectrally sensitized in blue, green, and red. In addition, anti-capri agents, stabilizers, main developing systems, hardeners, matting agents and the like may be added as appropriate. The binder for the silver halide emulsion is preferably gelatin, although some or all of the gelatin may be replaced with other natural and/or synthetic hydrophilic colloids, such as albumin, casein, polyvinyl alcohol, sodium alginate, sodium salt of carboxymethyl cellulose, etc. You can leave it there.

The lithographic printing plate of the present invention has an image-receiving layer containing physical development nuclei. Physical development nuclei include antimony, bismuth,
Known metals such as cadmium, cobalt, palladium, nickel, silver, lead, and zinc and their sulfides can be used. The image-receiving layer does not need to contain hydrophilic colloids, such as gelatin, carboxymethyl cellulose, gum arabic, sodium alginate, hydroxyethyl ill,! Hydrophilic colloids such as kistrin, hydroxyethyl cellulose, polystyrene sulfonic acid, copolymers of vinylimidazole and acrylamide, polyvinyl alcohol, etc. per square meter, preferably 0.1
It can be contained in amounts up to gram.

Hygroscopic substances such as humectants such as sorbitol, glycerol, etc. may be present in the image-receiving layer. Additionally, the image-receiving layer may also contain pigments for anti-scamming such as barium sulfate, titanium dioxide, china clay, and silver, developing agents such as hydroquinone, and hardening agents such as formaldehyde.

The support may be, for example, paper, film such as 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, metal, or metal. It can be a support of synthetic paper or metal/paper laminate. Paper supports coated on one or both sides with an alpha-olefin polymer, such as polyethylene, are also useful. These supports include
Anti-halicin dyes or pigments may also be incorporated.

The DTR treatment liquid used in the present invention includes an alkaline substance,
For example, hydroxide), potassium hydroxide, lithium hydroxide, tertiary phosphate), sulfites as preservatives, silver halide solvents, such as thiosulfates, thiocyanates, cyclic imides, Thiosalicylic acid, amines, etc.
Thickening agents such as hydroxyethylcellulose, carboxymethylcellulose, anti-fogging agents such as potassium bromide, 1-phenyl-5-mercagutotetrazole, the compound described in JP-A-47-26201, developers such as hydroquinone, 1- Phenyl-3-birasolitone, development modifiers such as polyoxyalkylene compounds, onium compounds, etc. can be included.

In implementing the silver complex diffusion transfer method, for example, British Patent No. 1,000,115, British Patent No. 1,012,476,
No. 1,017,273; is being mixed in. Therefore, for such materials, the processing solution used in the development step is a so-called "alkaline activating solution" that does not contain a developer.

The lithographic printing plate manufactured according to the present invention is, for example,
8-29723, U.S. Pat. No. 3,721,539, etc., the ink receptivity can be changed or enhanced by compounds such as those described in the specification.

The printing method, the desensitizing liquid, the dampening liquid, etc. used can be any commonly known method.

The invention will be explained below with reference to examples, but of course the invention is not limited thereto.

(G) Example A matting layer containing silica particles with an average particle size of 5 μm was provided on one side of a subbed-treated polyester film support, and a matting layer containing carbon black on the opposite side, with a 20. Antihalation undercoat layer (p) i 4 containing 1lfjt% of silica powder with an average particle size of 7 μm
．． A spectrally sensitized high-sensitivity silver chloride emulsion/1i (adjusted to 0) and a spectrally sensitized high-sensitivity silver chloride emulsion/1i (pH 4 , adjusted to 0). Is the gelatin in the undercoat layer 3°0 f/rr? , gelatin in the emulsion layer is 1.0
97 m'', coated in a ratio of 1.0 to 1.0 silver halide to silver nitrate. The basecoat and emulsion layers contained formalin as a hardener, with a ratio of 5.0 to 5.0 to 5.0 to 1.0 to 1.0 to 1.0 to 1.0 to 1.0 to 1.0 to 1.0 by 1.0 to 1.0 by 1.0 to 5.0 to 1.0 to 1.0 to 1.0 to 1.0 to 1.0, by 1.0 to 5.0, to 5.0 to 5.0, to gelatin, of formalin as a hardening agent. After drying and heating at 40°C for 14 days, the emulsion layer was coated with a nuclear solution (the polymer was a combination of A3 acrylamide and imidazole) as described in Example 2 of JP-A-53-21602. Polymer, hydroquinone is 0.8
(containing at a ratio of f/f) is coated and dried, and the entire lithographic printing plate is manufactured. The silver halide is a silver iodochloride emulsion containing 2 mol% of silver iodide (this silver halide has an average grain size of 0.3 μm, and more than 90% of the total grains are within ±30% of the average grain size). After chemically ripening the crystals (distributed cubic crystals) using conventional gold sensitization method and sulfur sensitization method, the emulsion is divided. As shown in Table 1 below, a predetermined amount of the solvent used in the present invention is added to a predetermined amount of a sensitizing dye solution completely dissolved in alcohol or the like.

All 10 kinds of lithographic printing plates were manufactured by the above-mentioned method and divided into samples in order to examine the following quality characteristics (Spectral sensitivity ■ Inkiri characteristics). One was a light wedge exposure using a sensitometer with a light source at a color temperature of [2666°K]. The other one uses a camera processor CP-404-11 (manufactured by Dainippon Screen) for the purpose of investigating the printing characteristics of a printing plate (offset master), and a direct contact screen (manufactured by Dainippon Screen) is placed on the plate. The film was exposed to light in close contact with the film and developed. Development treatment after exposure was performed using the following diffusion transfer developer.

Transfer developer> After the development process, the original plate was completely passed between two squeezing rollers to remove excess developer, and immediately treated with a neutralizing solution having the following composition at 25°C for 20 seconds, and the excess was removed using a squeezing roller. The solution was removed and dried at room temperature.

Neutralizing Solution> Regarding the spectral sensitivity, the reflection density was measured using a densitometer manufactured by Macbeth, and the total sensitivity (white) and rt are shown in Table 1.

Table 2 shows the ink receptivity, stain evaluation (water retention), and image reproducibility (sharpness and resolution) of the valley sample as a printing plate.
, showed the results of printing durability.

However, the characteristics of the sample were evaluated as follows.

b) Ink receptivity characteristics: As soon as the inked roller comes into contact with the printing plate, the paper begins to be fed, until a print with a good image is obtained.
000 sheets were printed, and the degree of staining of the printed matter was evaluated on the following three scales.

1. Complete damage and stains occur.

2. Partial or light stains occur.

3. No stains occur at all.

c) Image reproducibility (sharpness and resolution) - Tsuka reproducibility is 100,13 for gray contact screen.
3. Using 150.175 and 200i/inch, the screen was rated from 1 (100 lines/inch) to 5 (200 lines/inch) based on the number of screen lines at which fine halftone dots (5% dots) could be clearly reproduced. It is expressed in 5 steps (inches).

2) Printing durability: After printing 4,000 or more sheets, the paulownia durability is evaluated based on the number of sheets that cannot be printed due to staining or rusting of the iron, based on the following criteria.

1. 4,000 sheets or less 2. 4,000 to 6,000 sheets 3, 6,000 to 500 sheets 4, 8,000 to 10,000 sheets 5- 10,000 sheets or more (hereinafter referred to as margin) As understood from Tables 1 and 2 above, the present invention Compared to the comparative sample, the sample exhibits extremely superior properties in controlling stain generation and reproducing the same sensitivity with a smaller amount of dye. The printing plates containing only the dyes (■, ■, ■) used in the comparison were significantly inferior in terms of control of printing stains compared to the printing plates containing the dyes to which the solvent used in the present invention was added. I found out that there is.

Example 2 When preparing a lithographic printing plate similar to Example 1, the solvent used in the present invention was not contained in the emulsion layer, but the following liquid was drained, and palladium sulfide was coated on the pickled emulsion layer. The solvent was contained in the liquid contact layer.

Preparation of palladium sulfide sol Mix solutions A and B with stirring, and after 30 minutes, purify them through a column containing an ion exchange resin for producing pure water.
The following solution C was added to prepare a room solution.

However, the solvent used in the present invention was added to Solution C.

Table 3 shows the lithographic printing plate samples thus obtained, the predetermined amount of solvent contained therein, and the printing characteristics.

From the results in Table 3, it can be seen that the samples according to the present invention have extremely well controlled occurrence of printing stains compared to the comparative samples.

Further, Table 4 shows the printing test results for representative samples obtained in Examples 1 and 2 when the printing plates of the present invention were completely stored under high temperature and high humidity conditions and when they were left to stand naturally.

As is clear from Table 4, it is understood that the printing plate has very good printing characteristics, especially control of stain generation, and furthermore, has high sharpness, high resolution, and high printing durability. . Furthermore, it is understood that even when the samples according to the present invention are stored under severe conditions, there is no deterioration in the X-ray characteristics and the 611% accuracy.

(Margin below)

Claims (1)

[Scope of Claims] A lithographic printing plate using transferred silver by a silver complex diffusion transfer method as an ink receiving part, the printing plate having a silver halide emulsion layer and a physical development nucleus layer on a support, and A printing plate material containing 1 to 100 mg/m^2 of a solvent having the general formula described in [I] and/or [II] in both layers or in one layer. [I]R^1O-CH_2CH_2OX (In the formula, R^1 represents an alkyl group, an aryl group, an aralkyl group, a heterocyclic residue, or an alkenyl group; and X represents hydrogen or a lower acyl group.) [II] R^ 2-Y-R^3 (In the formula, R^2 and R^3 may be the same or different,
Each represents an alkyl group or an aryl group. In addition, Y is a divalent group, and indicates ▲There are mathematical formulas, chemical formulas, tables, etc.▼, ▲There are mathematical formulas, chemical formulas, tables, etc.▼, ▲There are mathematical formulas, chemical formulas, tables, etc.▼. Here, R^4 represents a lower alkyl group. )