JP2002182395A - Plate making method for planographic printing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve releasability of a hydrophilic binder layer such as a silver halide emulsion layer in a means of pressing a release material such as a release sheet on a planographic printing plate after development, releasing the hydrophilic binder layer and transferring it to the top of the release material. SOLUTION: In the photomechanical process in which a planographic printing plate having a silver halide emulsion layer on an anodically oxidized aluminum base and utilizing a silver complex salt diffusion transfer process is developed by applying a developing solution to the plate surface, a release material is pressed on the planographic printing plate and at least the silver halide emulsion layer is released and transferred to the top of the release material, 0.001-0.025 mol/m2 hydroquinone or its derivative is contained in the silver halide emulsion layer and/or a layer having the relation of water permeability with the silver halide emulsion layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method of making an aluminum lithographic printing plate using an aluminum plate as a support and utilizing a silver complex salt diffusion transfer method.

[0002]

2. Description of the Related Art A lithographic printing plate using a silver complex salt diffusion transfer method (DTR method) is described in "Photographic Silver Halide." Some examples are described in "Diffusion Processes", pp. 101-130.

There are two types of lithographic printing plates using the DTR method, a two-sheet type in which a transfer material and an image receiving material are separated, or a mono-sheet type in which they are provided on a single support. For the former, see, for example,
JP-A-158844 discloses the latter, for example, JP-B-48-30562, JP-B-51-15765, and JP-A-5-15765.
It is described in detail in respective gazettes such as 1-1111103 and 52-150105.

A monosheet type lithographic printing plate utilizing an aluminum plate as a support and utilizing a silver complex salt diffusion transfer method (hereinafter referred to as an aluminum lithographic printing plate) is disclosed in
No. 118244, No. 57-158844, No. 63-2
60491, JP-A-3-116151, 4-28
No. 2,295, U.S. Pat. Nos. 4,567,131 and 5,427,889.

The aluminum lithographic printing plate has a basic structure in which a physical development nucleus is supported on a roughened and anodized aluminum support, and a substantially uncured silver halide emulsion layer is provided thereon. Consists of A general plate-making method of this aluminum lithographic printing plate comprises the steps of exposure, development, washing with water (wash-off: removal of the silver halide emulsion layer), and finishing.

More specifically, a metal silver image portion is formed on a physical development nucleus by a development process, and a silver halide emulsion layer is removed by a subsequent washing process to form a metal silver image portion (hereinafter referred to as silver) on an aluminum support. Image portion) is exposed. At the same time, the anodized aluminum surface itself is exposed as a non-image area.

The exposed silver image area and the non-image area are treated with a finishing solution containing a protective colloid such as gum arabic, dextrin, carboxymethylcellulose, polystyrene sulfonic acid, etc. to protect the silver image area and the non-image area. Is applied. This finishing solution is also called a fixing solution or a finishing solution, and generally contains a compound (for example, a nitrogen-containing heterocyclic compound having a mercapto group or a thione group) that renders a silver image portion lipophilic.

In the above plate making method, a large amount of washing liquid is required for washing off the silver halide emulsion layer, and as a result, a large amount of waste liquid is generated. Therefore, a method of peeling and removing a silver halide emulsion layer that does not generate waste liquid is desired.

As one of the peeling and removing methods, Japanese Patent Laid-Open No.
Nos. 116151 and 4-318553 propose that a silver halide emulsion layer is peeled off by closely attaching a peeling sheet. However, it has been difficult to always stably release and transfer a hydrophilic binder layer such as a silver halide emulsion layer to a release sheet.

[0010]

SUMMARY OF THE INVENTION Accordingly, the present invention provides a lithographic printing plate which has been developed by pressing a release material such as a release sheet by pressing a release material such as a release sheet for the purpose of performing a stable plate making process with a small amount of waste liquid. It is an object of the present invention to improve the releasability of the hydrophilic binder layer in a plate-making method in which the hydrophilic binder layer is peeled off and transferred onto a release material.

[0011]

SUMMARY OF THE INVENTION It is an object of the present invention to develop a lithographic printing plate utilizing a silver complex salt diffusion transfer method having a silver halide emulsion layer on an anodized aluminum support. In a plate-making method wherein at least the silver halide emulsion layer is peeled by pressing a release material against a plate and transferred onto the release material, the silver halide emulsion layer and / or
Or a layer having a water-permeable relationship with the silver halide emulsion layer contains 0.001 to 0.025 mol of hydroquinone or a derivative thereof per square meter, which is solved by a method of making a lithographic printing plate. Was. Furthermore, as a more preferred embodiment of the present invention, a fresh developing solution is always applied to the plate surface of the lithographic printing plate during development and developed, and then the silver halide emulsion layer is peeled off by the above-mentioned method, thereby further reducing the amount of waste liquid. And stable processing could be realized. Hereinafter, the present invention will be described in more detail.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A lithographic printing plate used in the present invention generally has a physical development nucleus layer and at least a silver halide emulsion layer in this order on an aluminum support. However, it is known that DTR development is possible without using a physical development nucleus, and it is not necessary to use it.
The aluminum support is a roughened and anodized aluminum plate, at least 1.0 g per square meter,
Preferably, one having 1.5 g to 5 g of porous aluminum oxide is used.

The physical development nuclei of the physical development nucleus layer preferably used in the present invention may be those used in a known silver complex diffusion transfer method, for example, a colloid of gold, silver or the like, or a water-soluble salt of palladium, zinc or the like. A metal sulfide obtained by mixing sulfide with sulfide can be used. In some cases, it can be carried out without using a physical development nucleus. Various hydrophilic colloids can be used as the binder. These details and the production method are described, for example, in JP-B-48-30562.
JP-A-48-55402 and JP-A-53-21602.
Issue, Focal Press, London New York (19
See, "Photographic Silver Halide Diffusion Processes", published by Andrelot and Edith Weide.

The silver halide emulsion grains used in the present invention can be formed by various methods known so far. That is, any of an acidic method, a neutral method, an ammonia method and the like may be used, and a method of reacting a soluble silver salt with a soluble halide may be any of a single jet method, a double jet method, a combination thereof and the like. . As one type of the double jet method, a method in which pAg in a liquid phase in which silver halide is formed is kept constant, that is, a controlled double jet method can be used. Further, as described in British Patent Nos. 1,535,016, JP-B-48-36890, and JP-B-52-16364, the addition rate of silver nitrate or an aqueous alkali halide solution is changed according to the grain formation rate. How to make
U.S. Pat. No. 4,242,445, JP-A-55-158
No. 124 or the like, a method of changing the concentration of the aqueous solution may be used, and a method of rapidly growing the solution within a range not exceeding the critical supersaturation degree may be used. In addition, multilayer structured particles such as core-shell particles composed of the inside (core portion) and the outside (shell portion) of the particles can also be used.

The silver halide emulsion used in the present invention is:
The silver halide is selected from silver chloride, silver bromide, silver chlorobromide, silver chloroiodobromide, silver iodobromide, etc., which are generally used. Silver chloride is 70 mol% or more, preferably 90 to 100 mol%. Is preferred. The content of silver iodide is preferably from 0 to 2 mol%, more preferably from 0.1 to 1.0 mol%. In particular, it is preferable that after the silver iodide has formed silver chloride grains, a water-soluble iodide is added to convert the surface of the silver chloride grains with silver iodide. It is preferable to use a metal salt such as a rhodium salt or an iridium salt when forming a silver halide crystal.

The shape of the silver halide grains used in the present invention is particularly preferably a regular one such as a cube, but other octahedral, irregular or plate-like. There may be. The average grain size of the silver halide is preferably 0.6 μm or less, more preferably 0.1 to 0.5 μm, and the grain size distribution is 9 μm or less.
Monodisperse silver halide grains in which 5% of the grains fall within ± 30%, preferably ± 20% of the number average grain size are preferred.

Gelatin is used as a binder for the silver halide emulsion layer. For gelatin, acid-treated gelatin,
Various gelatins such as alkali-treated gelatin can be used. Further, those modified gelatins (for example, phthalated gelatin, amidated gelatin, etc.) can also be used. Further, a binder such as polyvinylpyrrolidone, various starches, albumin, polyvinyl alcohol, gum arabic, and hydroxyethyl cellulose can be contained.

In general, the silver halide emulsion of the present invention is preferably subjected to desalting and then sensitized with various chemical sensitizers, such as sulfur sensitization, reduction sensitization, gold sensitization and selenium sensitization. Sensitization, tellurium sensitization, etc., but gold sensitization using chloroauric acid, trichloroauric acid, thiocyanateauric acid or the like as a sensitizer is preferred. More preferably, chemical sensitization by sulfur plus gold sensitization is most preferable. As a sulfur sensitizer, in addition to sulfur compounds contained in gelatin,
Various sulfur compounds such as thiosulfates, thioureas, thiazoles, rhodanines and the like can be used.

A more preferred embodiment of the present invention is a plate-making method in which a fresh developing solution is always applied to the plate surface of a lithographic printing plate for development, and the applied amount of the developing solution is 100 ml or less, more preferably 80 ml per square meter. The following can be greatly reduced, and the waste liquid of the developing solution is not substantially generated or can be significantly reduced. In the lithographic printing plate used in such a coating and developing method, the silver halide emulsion layer is preferably 70% by weight or less based on silver halide in terms of silver nitrate,
More preferably, a binder of 60 to 20% by weight is used (hereinafter referred to as a high silver density emulsion). When the number of silver halide emulsion layers contributing to photosensitivity is two or more, it is preferable that the total weight ratio of the silver halide emulsion and the binder is adjusted to fall within the above range.

The high silver density emulsion which is more preferable for the coating and developing method of the present invention can greatly reduce the amount of the developing solution to be applied, and as a result, the amount of waste of the developing solution can be greatly reduced. The degree of tolerance to changes in environmental conditions is increased, and development time can be reduced (rapid development). Also, a lithographic printing plate having excellent printing characteristics can be obtained despite the reduced amount of silver halide to be applied.

The hydroquinone or a derivative thereof according to the present invention refers to 1,4-dihydroxybenzene or an alkyl or substituted alkyl, aryl or substituted aryl, halogen, hydroxy at a position other than the 1,4-position of the 1,4-dihydroxybenzene. Group, refers to a compound having at least one substituent selected from alkoxy groups, specifically, 2-chlorohydroquinone, 2-methylhydroquinone, etc., and most preferably unsubstituted 1,4-dihydroxybenzene. is there.

The hydroquinone or a derivative thereof of the present invention is contained in a silver halide emulsion layer and / or a layer having a water-permeable relationship with the silver halide emulsion layer. The layer having a water-permeable relationship with the silver halide emulsion layer is, for example, an intermediate layer provided between the aluminum support and the silver halide emulsion layer, or a layer provided on the silver halide emulsion layer. Protective layer and the like.

The content of hydroquinone or a derivative thereof used in the present invention is in the range of 0.001 to 0.025 mol, preferably 0.0025 to 0.0175 mol per square meter of the lithographic printing plate. is there. When the silver halide emulsion layer is the uppermost layer, it is preferable that the silver halide emulsion layer contains at least 50 mol% of the total content of hydroquinone or a derivative thereof. When a protective layer is provided, the protective layer preferably contains at least 50 mol% of the total content of hydroquinone or a derivative thereof.

As the binder for the protective layer used in the present invention, hydrophilic binders such as various kinds of gelatin, polyvinylpyrrolidone, various kinds of starch, albumin, polyvinyl alcohol, gum arabic, hydroxyethylcellulose and the like as described in the silver halide emulsion are used. One type or a combination of two or more types can be used.

The amount of the binder applied to the protective layer is in the range of 0.1 g to 3 g, preferably 0.3 to 2 g, per square meter of the aluminum lithographic printing plate, and may be two or more layers.

The aluminum lithographic printing plate of the present invention has a coating amount of silver halide in terms of silver nitrate of 0.5 g to 5 g, preferably 1.0 to 3.0 g per square meter.
Is preferably within the range.

The silver halide emulsion of the present invention can be spectrally sensitized using a dye known as a sensitizing dye in the photographic industry. In particular, 600 for scanning exposure of a red light source (helium / neon laser, red LED, etc.)
It is preferable to use a sensitizing dye having a spectral absorption at about 700 nm. These dyes include cyanine dyes, merocyanine dyes, composite cyanine dyes, composite merocyanine dyes,
Examples include holo-holer cyanine dyes, hemicyanine dyes, styryl dyes, and hemioxanol dyes. These sensitizing dyes may be used alone or in combination. Combinations of sensitizing dyes are often used, especially for supersensitization. Along with the sensitizing dye, the emulsion may contain a dye which does not itself have a spectral sensitizing effect or a substance which does not substantially absorb visible light and exhibits supersensitization.

In the silver halide emulsion layer, if necessary, various surfactants such as anions, cations, betaines and nonionics, quaternary ammonium salts, thioether compounds, polyethylene oxide derivatives, antifoggants such as mercaptotetrazole, A chelating agent such as ethylenediaminetetraacetate may be contained.

Further, in the present invention, the method described in JP-A-3-116151 is used between the aluminum support and the silver halide emulsion layer.
And the intermediate layer described in JP-A-4-282295.

The developer used in the present invention includes developing agents such as polyhydroxybenzenes such as hydroquinone, 3-pyrazolidinones such as 1-phenyl-3-pyrazolidinone and derivatives thereof, alkaline substances such as potassium hydroxide and water. Sodium oxide, lithium hydroxide, tertiary
Sodium phosphate or amine compounds, preservatives such as sodium sulfite, thickeners such as carboxymethylcellulose, antifoggants such as potassium bromide, development modifiers such as polyoxyalkylene compounds, chelating agents such as ethylenediaminetetraacetic acid, Silver halide solvents, for example, thiosulfates such as sodium thiosulfate and potassium thiosulfate, 2-mercaptobenzoic acid and derivatives thereof,
Cyclic imides such as uracil, alkanolamines,
Diamines, mesoionic compounds, thioethers and the like can be mentioned. The pH of the developer is 11 to 14, especially pH 1
It is preferably 1.5 to 13.5.

The total amount of the developing agent in the developing solution of the present invention is an amount that can theoretically reduce at least 50% of the silver halide of the lithographic printing plate, and preferably reduces at least 75%. In large amounts.

The developing solution preferably further contains a compound (lipophilic agent) for making the silver image area lipophilic. Examples of lipophilic agents include Focal Press, London New York (1972), by Andrelot and Edith Weide, Photographic Silver Halide Diffusion Processes, 105, 10
Compounds described on page 6 can be mentioned. For example, there are a compound having a mercapto group or a thione group and a quaternary ammonium compound. In the present invention, a compound having a mercapto group or a thione group is preferably used. Particularly preferred are nitrogen-containing heterocyclic compounds having a mercapto group or a thione group, and JP-B-48-2972.
No. 3, JP-A-58-127928 and the like.

The development of the present invention can be carried out by a so-called immersion developing system, but from the viewpoint of reducing the amount of waste liquid, it is preferable to use a coating and developing system which is a more preferred embodiment of the present invention. Coating of a developer is described in, for example, JP-A-48-76603, JP-A-5-289343,
No. 6-27680, No. 6-27682, No. 1
No. 0-62952, No. 10-62951, Japanese Patent Application No. 1
A developer coating apparatus such as that described in JP-A-1-361027 can be used.

The temperature of the developer is preferably in the range of about 15 ° C. to about 30 ° C., and the development time can vary up to 30 seconds.
These conditions can be appropriately determined depending on the developing device, the structure of the aluminum lithographic printing plate, the composition of the developer, and the like.

When the development is completed, the plate surface of the lithographic printing plate is replaced with, for example, JP-A-3-116151 and JP-A-4-3151.
Release material (release sheet) as described in Japanese Patent No. 18553 and below
To peel off the hydrophilic binder layer such as the silver halide emulsion layer and transfer it onto the release sheet. The release material may be a release roller other than the release sheet described above.

This mechanical peeling step is extremely important for the printing performance of an aluminum lithographic printing plate, because if a hydrophilic binder such as gelatin remains on the aluminum plate, the ink receptivity and printing durability deteriorate. Process.
It was found that when a very large amount of the developing solution was accumulated on the plate surface, even if the release sheet was brought into close contact with the emulsion layer, it did not adhere well to the emulsion layer. Therefore, in the coating and developing method in which only a relatively small amount of the developer is supplied to the plate surface, relatively good peeling can be realized. It is preferable to prevent excess developer from remaining on the surface by scraping off excess developer or squeezing it with a squeegee means (a squeeze roller). Even when using coating and developing, depending on the composition of the lithographic printing plate or the composition of the developing solution, before the peeling step, some developer present on the plate surface is squeezed with a squeegee means and then adhered to the peeling sheet. May be.

In this peeling step, the contact time between the lithographic printing plate and the peeling material is preferably within 5 seconds, more preferably within 3 seconds.
More preferably, it is within 2 seconds. The environmental temperature at the time of close contact between the lithographic printing plate and the release material is preferably in the range of about 10 ° C to about 30 ° C, and more preferably in the range of about 10 ° C to about 25 ° C. More stable peeling without deterioration of printing quality such as printing durability can be performed.

The release sheet preferably used in the present invention is a material having a void layer in which fine particles are dispersed with a binder on a support, and has a liquid absorption of 0.1 second after contact with a liquid. It is a material having a characteristic of having a high liquid absorption rate such as 60% or more of the liquid absorption amount after 0.2 seconds, and particularly preferably a material having a ratio of 70% to 100%. Furthermore, a material having a liquid absorption of 0.1 ml or more, preferably 15 ml or more, and particularly preferably 20 ml or more (up to about 80 ml although there is no upper limit) per 0.1 m 2 after contact with the liquid. is there. Such a liquid absorption amount can be measured by, for example, a measuring device by the Bristow method (for example, a dynamic scanning liquid absorption meter).

A particularly preferred specific example of the release sheet of the present invention is a material having a void layer in which fine particles are dispersed with a binder on a support. As the fine particles, inorganic and organic fine particles can be used, for example, soft calcium carbonate, heavy calcium carbonate, kaolin, talc, calcium sulfate,
Barium sulfate, titanium dioxide, zinc oxide, zinc sulfide, zinc carbonate, satin white, aluminum silicate, diatomaceous earth, calcium silicate, magnesium silicate, synthetic amorphous silica, colloidal silica, colloidal alumina, pseudoboehmite, aluminum hydroxide, alumina , Lithopone, zeolite, hydrohalosite, magnesium carbonate, inorganic fine particles such as magnesium hydroxide, and further polystyrene,
Organic fine particles such as polymethyl methacrylate are exemplified.

The average particle diameter of the fine particles is 10 μm
The following is general, and the lower limit can be a primary particle diameter of several nm.

The coating amount of the fine particles is preferably 3 g or more, particularly preferably 5 g or more per square meter, and the upper limit is about 30 g.

As the binder for dispersing the fine particles, various known hydrophilic binders can be used. For example, gelatin and its derivatives, polyvinylpyrrolidone,
Pullulan, polyvinyl alcohol and its derivatives, polyethylene glycol, carboxymethylcellulose, hydroxyethylcellulose, dextran, dextrin, polyacrylic acid and its salts, agar, carrageenan,
Xanthen gum, locust bean gum, alginic acid,
Examples thereof include gum arabic, polyalkylene oxide copolymers, water-soluble polyvinyl butyral, and homo- or copolymers of vinyl monomers having a sulfonic acid group.

It is preferable to use the above-mentioned binder in a small ratio with respect to the fine particles in that a void layer having a high liquid absorption rate can be obtained. The weight ratio between the fine particles and the binder is usually 1
The range of 00:90 to 100: 0.5 is preferred.

It is preferable to use a crosslinking agent (hardener) together with the binder. Specific examples of the crosslinking agent include:
Aldehyde compounds such as formaldehyde and glutaraldehyde, ketone compounds such as diacetyl and chloropentanedione, 2-hydroxy-4,6-dichloro-
1,3,5 triazine, U.S. Pat. No. 3,288,775
Compounds having a reactive halogen as described in US Pat. No. 3,635,718, compounds having a reactive olefin as described in US Pat. No. 3,635,718, US Pat.
N-methylol compounds as described in U.S. Pat. Nos. 32,316; isocyanates as described in U.S. Pat. No. 3,103,437; U.S. Pat. Nos. 3,017,280 and 2,983;
611, carbodiimide compounds as described in U.S. Pat. No. 3,100,704, epoxy compounds as described in U.S. Pat. No. 3,091,537, halogen carboxaldehydes such as mucochloric acid, There are dioxane derivatives such as dihydroxydioxane, and inorganic crosslinking agents such as chromium alum, zirconium sulfate, boric acid and borate, and these can be used alone or in combination of two or more.

To apply the fine particle void layer, it is preferable to add at least one surfactant of an anionic, cationic, nonionic or betaine type.

The void layer may be a single layer or two or more layers. Alternatively, a non-void polymer layer may be provided below the void layer.

The support for the release sheet may be either a transparent or opaque support. For example, high quality paper, medium quality paper, super calendered paper, single gloss base paper,
Non-coated paper such as tracing paper, art paper, coated paper, measurement coated paper, finely coated paper, coated paper such as cast coated paper, paper coated with resin such as polyethylene, non-woven fabric,
Any material such as a cloth, further, a polyester resin, a polycarbonate resin, a cellulose acetate resin, an acrylic resin, cellophane, an aluminum foil, and a composite support thereof can be used.

There is no limitation on the thickness of the support.
Micron, preferably in the range of 30-300 microns.

The release sheet may be in the form of a sheet having substantially the same size as the lithographic printing plate, but in order to perform continuous processing in the plate making apparatus, a long roll-shaped sheet as shown in FIG. Is preferred. The long roll of the release sheet (4) is fed from the original winding roller (6), comes into contact with and adheres to the plate surface, and is wound by the winding roller (7).

After the stripping step, a neutralization stabilization treatment for stopping the progress of development may be performed, and the neutralizing solution may contain the lipophilic agent described above. When a neutralizing solution is used, it is desirable to apply a required amount with a coating device and to generate as little waste liquid as possible.

The silver image portion and the non-image portion exposed on the aluminum lithographic printing plate surface are treated with a finishing liquid in order to increase their lipophilicity and hydrophilicity and to protect the plate surface. In the present invention, it is preferable that the finishing liquid is also applied using a coating device. The finishing liquid contains arabic gum, dextrin, sodium alginate, propylene glycol ester of alginic acid, hydroxyethyl starch, carboxymethylcellulose, hydroxyethylcellulose, polyvinylpyrrolidone, and polystyrene sulfone to protect the anodized layer in the non-image area and improve hydrophilicity. It is preferable to contain a protective colloid such as an acid and polyvinyl alcohol. Further, in order to further improve the lipophilicity of the image area, it is preferable to contain the above-mentioned lipophilic agent or enzyme.

[0052]

EXAMPLES The present invention will be described below with reference to examples. Example 1 The electrolytic surface roughening treatment and anodizing of an aluminum support were carried out according to the method described in U.S. Pat. No. 5,427,889 on a plate having an average diameter of about 5 [mu] m.
0.30 μm pits of about 2,70 per 100 μm 2
0 pits and the average diameter of these pits is 0.13μ
m of an aluminum plate having a thickness of 0.30 mm was obtained. This aluminum plate is anodized after roughening treatment.
It had 2.0 g of porous aluminum oxide per square meter and the average roughness (Ra) was 0.4-0.5 μm.

A palladium sulfide nucleus solution was applied to the aluminum support and then dried. The amount of nuclei contained in the physical development nucleus layer was 3 mg / m ² .

A silver halide emulsion was prepared by using alkali-treated gelatin as a binder, and adding potassium hexachloroiridate (IV) having an average particle size of 0.3 μm to the mixture by a control double jet method in an amount of 0.006 per mol of silver.
A silver chlorobromide emulsion containing 1.5 mol% of silver bromide doped with millimoles was prepared, and at the end of physical ripening, converted with a KI equivalent to 0.3 mol% of silver iodide to prepare a silver chloroiodobromide emulsion. did. Thereafter, the emulsion was flocculated and washed. Further, gelatin was added to this emulsion, subjected to sulfur gold sensitization, a stabilizer was added, and spectral sensitization was performed using 3 mg of a red-sensitive sensitizing dye per 1 g of silver. In this emulsion, the ratio of silver halide to gelatin in terms of silver nitrate was 8: 3 by weight.

A surfactant was added to the silver halide emulsion thus prepared to prepare a coating solution. The emulsion layer coating solution was applied on the aluminum support coated with the physical development nuclei and dried so that the amounts of silver and gelatin in terms of silver nitrate were 2 g and 0.75 g per square meter to obtain a lithographic printing material. (Sample A). Also, 0.0005 per square meter in the silver halide emulsion,
0.0015, 0.003, 0.0075, 0.01
A lithographic printing material sample B was prepared in the same manner as sample A except that it contained 5, 0.02 and 0.03 mol of hydroquinone.
C, D, E, F, G, H.

0.0% per square meter on sample A
005, 0.0015, 0.0075, 0.02,.
Samples I, J, K, L, and M were prepared with a gelatin protective layer (coating amount: 0.5 g / m ² of gelatin) containing 03 mol of hydroquinone.

The sample (half size of chrysanthemum) was 633 n
An image was output by an output device using a red LD laser of m as a light source, and then a plate was made by a plate making processor shown in FIG. 1 to prepare a lithographic printing plate.

After the printing plate (P) is immersed in the developing tank (2) and developed, the excess developing solution is squeezed by the squeegee roller pair (3), and then the release sheet and the pressure roller pair (5). And the silver halide emulsion layer on the printing plate (P) is transferred to the release sheet (4) and removed. The temperature of the developer is 23 ° C, and the printing plate (P) is transported by the pair of transport rollers (1).
Is about 12 seconds until it reaches the squeegee roller pair (3), and the contact time of the release sheet is about 0.2 seconds. Each sample was subjected to plate making for 10 plates, and the environmental temperature at the time of peeling was in the range of about 25 ° C. to about 30 ° C.

The release sheet was made of silica 1 having an average particle size of 7 nm.
A material having a void layer was used in which an aqueous solution dispersed in a ratio of 00 parts by weight to 30 parts by weight of polyvinyl alcohol was applied to a normal high-quality paper weighing 70 g / m ² so as to have an amount of 6 g / m ² of polyvinyl alcohol. .

The lithographic printing plate from which the emulsion film has been peeled off using a release sheet is immersed in a neutralizing solution and a finishing solution sequentially, and then dried.

The compositions of the developing solution, neutralizing solution and finishing solution are shown below. <Developer> Sodium hydroxide 25 g Polystyrene sulfonic acid and maleic anhydride copolymer (average molecular weight 500,000) 10 g Sodium ethylenediaminetetraacetate 2 g Sodium sulfite 100 g Monomethylethanolamine 25 g 2-Mercapto-5-nheptyl-oxadi Azole 0.5 g Sodium thiosulfate (pentahydrate) 8 g Hydroquinone 18 g 1-Phenyl-3 pyrazolidinone 3 g The total amount is made 1000 ml. pH (25 ° C.) = 13.1

<Neutralized Solution> 2-mercapto-5-n-heptyl-oxadiazole 0.5 g monoethanolamine 13 g sodium bisulfite 10 g potassium monophosphate 40 g The total amount is made 1000 ml. pH = 6.0

<Finishing Solution> Phosphoric Acid 0.5 g Monoethanolamine 5.0 g 2-Mercapto-5-n-heptyloxasiasol 0.5 g Polyglycerol (hexamer) 50 g The total amount is made 1000 ml. pH = 7.2

With respect to the lithographic printing plate thus prepared, a printing press Heidelberg TOK (trademark of an offset printing press manufactured by Heidelberg), an ink (New Champion Ink H manufactured by Dainippon Ink Co., Ltd.) and a commercially available PS printing plate were used. Printing was performed using the wet liquid. The results of the peeling state of the emulsion layer, the printing of the ink on printing, and the printing durability test are shown below. The peeled state is ○;
Visually, the emulsion layer was peeled without leaving any residue, and Δ: the emulsion layer was not partially peeled, which was represented by a two-step evaluation. The ink run was evaluated by the number of printed sheets until a sufficient ink density was obtained.
Evaluation was made in three stages of exceeding the number of sheets. The printing durability was evaluated by the number of prints when the silver image was lost and printing became impossible. All evaluations were represented by average values of 10 plates having different environmental temperatures at the time of peeling. Table 1 shows the results.

[0065]

[Table 1] ────────────────────────────────── Releasability Ink riding Printing durability Remarks ───── ───────────────────────────── Sample A △ × About 30,000 sheets Comparison Sample B △ △ About 50,000 sheets Comparison Sample C ○ ○ 100,000 sheets or more of the present invention Sample D ○ ○ 150,000 sheets or more of the present invention Sample E ○ ○ 150,000 sheets or more of the present invention Sample F ○ ○ 150,000 sheets or more of the present invention Sample G ○ ○ 100,000 sheets or more of the present invention Sample H △ △ About 60,000 sheets Comparative Sample I △ △ About 40,000 sheets Comparative Sample J ○ ○ 100,000 sheets or more of the present invention Sample K ○ ○ 150,000 sheets or more of the present invention Sample L ○ ○ 100,000 sheets or more of the present invention Sample M △ △ about 70,000 sheets comparison ──────────────────────────────────

Example 2 Next, instead of the developing tank (2) shown in FIG. 1 of Example 1, a coating and developing process is performed by using a developing device using a slot die shown in Japanese Patent Application No. 11-361027 to perform lithographic printing. Create a plate,
It was evaluated similarly. The developer was applied at 80 ml per square meter of the lithographic printing material. The development temperature was 21 ° C. and the development time was 15 seconds. Table 2 shows the results.

[0067]

[Table 2] ──────────────────────────────────── Releasability Ink-riding Printing durability Remarks ───試 料 Sample A △ × about 25,000 sheets Comparison Sample B △ △ about 6 100,000 sheets Comparison sample C ○ ○ 150,000 sheets or more Invention sample D ○ ○ 200,000 sheets or more Invention sample E ○ ○ 200,000 sheets or more Invention sample D ○ ○ 200,000 sheets or more Invention sample G ○ ○ 150,000 sheets More than the present invention Sample H △ △ About 60,000 comparison Sample I △ △ About 30,000 comparison Sample J ○ ○ 150,000 or more The invention Sample K ○ ○ 200,000 or more The invention Sample L ○ ○ 150,000 or more Invention Sample M ○ △ About 80,000 sheets Comparison ────────────────────────────────────

From Tables 1 and 2, it can be seen that a lithographic printing plate containing hydroquinone in the silver halide emulsion layer and / or in a layer having a water-permeable relationship with the silver halide emulsion layer shows good releasability. It can be seen that more stable peeling can be performed without deterioration of print quality such as riding and printing durability. It can also be seen that providing a protective layer containing hydroquinone is particularly effective.

[0069]

According to the method for making a lithographic printing plate of the present invention,
Demonstrate good releasability on the release material without deteriorating its release performance, and reduce the load on the processing solution of the next process such as a neutralized solution of a waste solution containing a silver halide emulsion layer after development processing. As a result, the amount of waste liquid can be reduced and stable plate making can be achieved. In a more preferred embodiment of the present invention, by applying and developing a developer, stable plate making with a smaller total waste liquid amount can be achieved.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view showing one example of a plate making apparatus used in a plate making method of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 conveyance roller pair 2 developing tank 3 squeegee roller pair 4 release sheet 5 pressure roller pair 6 (release sheet) original winding roller 7 (release sheet) winding roller

Claims (2)

[Claims] After developing a lithographic printing plate using a silver complex salt diffusion transfer method having a silver halide emulsion layer on an anodized aluminum support, the lithographic printing plate is pressed against a release material to at least In a plate-making method in which the silver halide emulsion layer is peeled off and transferred onto the release material, the silver halide emulsion layer and / or the layer having a water-permeable relationship with the silver halide emulsion layer may have a water permeability of 0.2 mm / sq.m. 001-001
A method for making a lithographic printing plate, comprising 0.025 mol of hydroquinone or a derivative thereof. 2. The method for making a lithographic printing plate according to claim 1, wherein a fresh developing solution is always applied onto the plate surface of the lithographic printing plate for development.