JPH02207257A - lithographic printing plate - Google Patents

Abstract

PURPOSE:To obtain the planographic printing plate which is improved in plate wear and for which a silver salt diffusion transfer method is used by incorporating a specific compd. into at least one constituting layer of the printing plate having silver halide emulsion layers and physical development nucleus layers. CONSTITUTION:This printing plate has at least the silver halide emulsion layer and the physical development nucleus layer on the substrate and the compd. expressed by the formula I is incorporated into at least one constituting layer. In the formula I, A denotes a hydroxyl group, amino group, etc.; R1, R2 form a ring together with a C atom to be combined or one thereof is a hydrogen atom and the other is a hydrogen atom, alkyl group, etc.; ; n denotes 0 to 8 integer; Q denotes -SO3M, -SO2M; M denotes a hydrogen atom or cation. The planographic printing plate which has the high plate wear and for which the silver salt diffusion method is used is obtd. in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of the Invention] The present invention relates to a lithographic printing material to which a silver salt diffusion transfer method is applied.

[Prior art]

A lithographic printing plate consists of an oleophilic image area that accepts oil-based ink and an oil-repellent non-image area that does not accept ink. Generally, the non-image area is a hydrophilic area that receives water. It consists of In normal planographic printing, both water and ink are supplied to the plate surface, and colored ink is selectively received in the image area and water is selectively received in the non-image area, and the ink on the image line is
For example, printing is performed by transferring the image onto a printing medium such as paper.

Therefore, in order to obtain good printed matter, the difference in lipophilicity and hydrophilicity between the printed area and the non-printed area must be large enough so that when water and ink are supplied to the printing plate, a sufficient amount of ink is applied to the printed area. It is necessary to apply a receiver, but not to apply any ink to the non-image areas.

In lithographic printing plates using the silver salt diffusion transfer method, especially in lithographic printing plates that have a nucleus layer on the emulsion layer, the silver salt crystals that have formed photosensitive nuclei upon exposure to light undergo chemical development and become black silver, becoming hydrophilic. On the other hand, the unexposed silver salt crystals become silver salt complexes due to the silver salt complexing agent in the developer and diffuse to the surface nuclear layer, and the presence of the nuclei prevents physical development. This forms an ink-receptive image mainly composed of silver.

In this way, in this lithographic printing plate, the silver layer deposited on the gelatin is used as an ink-receptive image area, so compared to a general lithographic printing plate (for example, a PS plate, etc.), the machine in the image area is It has the disadvantage that it has insufficient resistance to surface abrasion, and that the image area may be missing or the ink receptivity of the image area may gradually be lost.

If the degree of hardness of gelatin is increased or the amount of physical development nuclei is increased in order to overcome this drawback, scumming occurs and the printing durability of the lithographic printing plate is significantly reduced.

Therefore, there is a demand for a lithographic printing plate with higher printing durability.

Further, there are drawbacks such as background smearing and deterioration of ink receptivity when a lithographic printing plate is stored for a long period of time from manufacture to plate making.

[Purpose of the invention]

An object of the present invention is to provide a lithographic printing plate using a silver salt diffusion transfer method, which has improved printing durability.

Another object of the present invention is to provide a lithographic printing plate using the silver salt diffusion transfer method that has excellent printing performance and does not deteriorate on storage.

[Structure of the invention]

The above object of the present invention is to provide a lithographic printing plate having at least a silver halide emulsion layer and a physical development nucleus layer on a support, in which at least one constituent layer contains a compound represented by the following general formula (I). This was achieved by a lithographic printing plate featuring

General formula (1) represents R1 % formula %, R1 and R2 form a ring together with the cH atom to which they are bonded, or one is a hydrogen atom and the other is a hydrogen atom,
Represents an alkyl group, aryl group, hydroxyl group, n
is O or an integer from 1 to 8, Q is -8o5M or -802
M represents a hydrogen atom or a cation such as an alkali metal. ) Representative examples of the compound represented by the general formula (1) used in the present invention are shown below.

(1-1) HO-C)(2-8OsNa(I-
6) HO-(CH2)6-8OsNH4 HO-CH-8O5Na 2H5 03Na 03Na H Cl-4) HO-(CH2)2-8OsK (I-5) HO-CH-8O3Na CH3 (I-12) H2N-CH2 -80sNa 5O3Na (l-15) HO-CH2-8OxNa (I-16) HO-(CH2)2-8O2Na CI-18) H2N-CH2-8O2Na The compound of general formula (1) used in the present invention is: It may be contained in any of the constituent layers of the lithographic printing plate, or may be contained in two or more layers. Further, the compounds of general formula (I) may be used alone or in combination of two or more.

The content of the compound of general formula (I) is 0.1 to 5 per stingray.
00■, preferably in the range of 1 to 300■.

There is no particular restriction on the method of incorporating the compound of general formula CI) into the constituent layers, and it can be incorporated during the production of the coating solution, immediately before coating, or in-line during coating.

There are no particular restrictions on the method of coating the constituent layers; simultaneous multilayer coating,
Coating can be performed by a single layer coating method or a combination thereof.

The lithographic printing plate that is the object of the present invention contains gelatin, and the layer containing gelatin can be a subbing layer, an emulsion layer, or a catalyst layer. These gelatin-containing layers are usually hardened with gelatin hardeners.

Examples of gelatin hardeners include inorganic compounds such as chromium alum, aldehydes such as formalin, glyoxal, malealdehyde, and glutaraldehyde, N-methylol compounds such as urea and ethylene urea, and mucochlor i.
, aldehyde analogs such as 2,3-dihydroxy-1,4-dioxane, 2,4-dichloro-6-hydroxy-8-triasif salts, 2,4-dihydroxy-6-
Nitrogen-containing 6-membered ring compounds with active/logen such as chloro-8-triazine salts, divinyl sulfone, divinyl ketone and MMM-)lyacroylhexahydrotriazine with active vinyl groups, active 3-membered rings Compounds having two or more ethyleneimino groups or epoxy groups in the molecule, dialdehyde starch as a polymer hardening agent, etc. can be used alone or in combination of two or more.

Hardeners can be added to all layers, or only to some or several layers.

Of course, in the case of simultaneous coating of two layers, the diffusible hardener can be added to only one layer. It can be added during emulsion production or in-line during coating.

The gelatin in the gelatin-containing layer of the present invention is partially composed of water-soluble gelatin, station powder, dextrin, albumin, sodium alginate, hydroxyethylcellulose, gum arabic, polyvinyl alcohol, polyvinylpyrrolidone, carboxymethylcellulose, polyacrylamide, styrene. It can also be replaced with one or more hydrophilic polymers such as maleic anhydride copolymer, polyvinyl methyl ether-maleic anhydride copolymer, and the like.

Additionally, an aqueous vinyl polymer dispersion (latex) can be added to the gelatin layer.

The polymer binder in the undercoat layer is generally 0.5 to 10 t/r.
r? , preferably 1 to 62β. The undercoat layer may contain pigments, dyes, carbon black, etc. for the purpose of preventing halation, and may also contain an average particle size of 2 to 10 to improve printing durability.
May contain micron solid powders. Furthermore, photographic additives such as developing agents can also be included.

The undercoat layer is JP-A-48-5503 and JP-A-48-10.
0203, 16507 of 1972.

The silver halide emulsion layer is made of, for example, silver chloride, silver bromide, silver chlorobromide, and silver iodide in addition to these. The silver halide crystal may contain heavy metals such as rhodium salts, iridium salts, palladium salts, ruthenium salts, and copper salts. There is no particular restriction on the crystal form, and it may be monodisperse or polydisperse crystal, core-shell type crystal, or tabular crystal. One preferred example is monodisperse or polydisperse crystals containing 80% or more silver chloride and containing rhodium or iridium salts.

Silver halide can be sensitized in a variety of ways when it is manufactured or coated.

It can be chemically sensitized by methods well known in the art, such as with sodium thiosulfate, alkylthioureas, or with gold compounds such as gold rhodan, gold chloride, or a combination of both.

Silver halides can also be sensitized or desensitized, either positively or negatively, by organic sensitizing dyes such as cyanine, hemicyanine, and the like. There is no particular restriction on the wavelength range that can be sensitized or desensitized. Therefore, Orn sensitization, panchromatic sensitization,
Sensitization for helium-neon lasers, sensitization for argon lasers, sensitization for LEDs, sensitization for semiconductor lasers, and UV sensitization and visible light desensitization for bright rooms can be performed. The sensitized silver halide emulsions may also be suitable for high intensity short exposures.

The catalyst layer present above the emulsion layer contains physical development nuclei.

Physical development nuclei include fine particles of metals such as silver, antimony, bismuth, cadmium, cobalt, lead, nickel, palladium, rhodium, gold, platinum, iron, and sulfides, polysulfides, and selenides of these metals. It may be a mixture or a mixed crystal.

The catalyst layer may or may not contain a hydrophilic binder, but may include gelatin, starch, dialdehyde starch, carboxymethyl cellulose, gum arabic, sodium alginate, hydroxyethyl cellulose, polystyrene sulfonic acid, a copolymer of vinyl imidazole and acrylamide. Hydrophilic polymers such as polyvinyl alcohol or oligomers thereof can be included.

Furthermore, the catalyst core layer may contain a developing agent such as hydroquinone, methylhydroquinone, and catechol, and a known hardening agent such as formalin and succinic aldehyde.

Each coating layer, such as the undercoat layer, silver halide emulsion layer, and catalyst core layer, may contain some of anionic, cationic, or neutral surfactants as coating aids, and thickeners. It can also contain antistatic agents.

As a support for the lithographic printing plate, paper, a synthetic or semi-synthetic polymer film, a metal plate such as aluminum or iron, etc., can be used as long as it can withstand lithographic printing. The surface of the support can also be coated on one or both sides with one or more polymeric films or thin metal films. It is also possible to surface-treat the surface of these supports in order to improve adhesion with the coating layer.

Particularly preferably used supports include paper coated on both or one side with a polyolefin polymer, a polyester film, a polyester film whose surface has been treated to make it hydrophilic, and a surface-treated aluminum plate.

These supports contain pigments to prevent halation,
It may contain solid fine particles to improve surface properties. Further, the support may be light-transmissive so that back side exposure is possible.

The developing solution used in the present invention contains alkaline substances such as sodium hydroxide, potassium hydroxide, lithium hydroxide, trisodium phosphate, sulfite as a preservative, and silver halide solvents such as thiol, etc. Sulfates, thiocyanates, cyclic imides, 2-mercaptobenzoic acid, amines, etc., thickeners, -C1, hydroxyethyl cellulose, carboxymethyl cellulose, etc., anti-capri agents such as potassium bromide, Japanese Unexamined Patent Publication 1973-
As a developer, for example, the compound described in 26201,
Hydroquinones, catechol, 1-7enyl-3-pyrazolidone, etc., and as development modifiers, for example, polyoxyalkylene compounds, onium compounds, etc. can be included.

Furthermore, a second solution containing a compound that neutralizes alkalinity and improves the ink adhesion of the surface silver layer can also be used as the development processing solution.

The developed surface silver layer of the lithographic printing plate produced according to the present invention can be converted into ink receptivity or enhanced with any known surface treatment agent.

As such a treatment liquid, for example, Japanese Patent Publication No. 482972
3, as described in U.S. Pat. No. 3,721,559, etc.

The printing method, the desensitizing liquid, the dampening liquid, etc. used can be generally well-known methods.

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

Example 1 135 tA? ? A matting layer containing silica particles with an average particle size of 5μ is provided on one side of double-sided polyethylene-coated paper, and the other side is coated with carbon black after corona discharge machining and an undercoat layer (gelatin) containing silica powder with an average particle size of 7μ. 3.5 f/m') and an ortho-sensitized high-sensitivity silver chloride emulsion containing 0.1 t/l of 1-phenyl-3-pyrazolidone (containing 0.8 t/lr of gelatin). Two layers were simultaneously coated using silver nitrate at a thickness of 1.0 υ. As a hardening agent, 2,4-dichloro-6-hydroxy-8-) riazine sodium was added to the undercoat layer at 170η.
β was added in-line, and N-methylolethylene urea was added to the emulsion layer at a rate of 80 Tl1f/rrl. After drying,
Nucleus coating solution described in Example 2 of JP-A-58-21602 (
A lithographic printing plate serving as Comparative Example A of the present invention was prepared by coating a polymer containing a copolymer of acrylamide and imidazole with a jI of 6.3 and containing hydroquinone as a developing agent at a ratio of 0.81β) and drying.

The lithographic printing plate which is an example of the present invention has the above lithographic printing plate (comparative example A), and further contains an exemplified compound (1-
Four types of lithographic printing plates were prepared by containing 1), Cl-9), (I-11), and (I-15) in amounts of 2 to 50% each.

Immediately after production, these five types of lithographic printing plates were stored at 50°C and 80% relative humidity for 5 days, and then subjected to image exposure using a plate-making camera with an image reversal mechanism, followed by silver salt diffusion transfer development as described below. Developing treatment was performed using a solution at 30° C. for 1 minute.

<Transfer developer> Printing was performed using the following dampening liquid.

After the development process, the original plate is 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 is removed using a squeezing roller. The liquid was removed and dried at room temperature.

Neutralizing liquid〉 Humidifying liquid〉 The lithographic printing plate prepared by the above procedure was installed in an offset printing machine, and the following desensitizing liquid was applied to the plate surface.

The following evaluation criteria were used to determine the number of sheets printed when the image became unusable due to background smudges in non-print areas and missing silver images using a Dick offset printing machine (trademark). .

◎More than 20,000 sheets ○　10. ooo~20,000 pieces △　5. o o o ~ 10,000 pieces x 2. ooo~ 5,000 pieces The printing results are shown in Table 1.

Stability did not deteriorate.

〔Effect of the invention〕

According to the present invention, it is possible to improve the printing durability of a lithographic printing plate to which the silver salt diffusion transfer method is applied, and to improve the deterioration of its printing performance due to storage.

Example 2 Example 1 was followed except that the exemplified compound of Example 1 was contained in the silver halide emulsion layer. Similar results were obtained.

Example 3

Claims (1)

[Scope of Claims] 1. In a lithographic printing plate having at least a silver halide emulsion layer and a physical development nucleus layer on a support, at least one constituent layer contains a compound represented by the following general formula (I). A lithographic printing plate characterized by: General formula (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, A represents a hydroxyl group, an amino group, ▲There are mathematical formulas, chemical formulas, tables, etc.▼, and R_1 and R_2 are the rings together with the bonded C atoms. or one is a hydrogen atom and the other is a hydrogen atom, an alkyl group,
Represents an aryl group or a hydroxyl group, and n is 0 or 1 to
An integer of 8, Q represents -SO_3M or -SO_2M, and M represents a hydrogen atom or a cation. )