JP2000241982A - Production of planographic printing original plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To mass-produce a planographic printing original plate having stable quality used for manufacturing a planographic printing plate by removing a thin silver film by heat-mode laser beam exposure. SOLUTION: A physical developing nucleus layer is disposed on a web-shaped substrate having a hydrophilic surface or provided with a hydrophilic layer. The top of the substrate or a substrate having a surface active to physical development is coated with a silver halide emulsion layer, a diffusion transfer developer is supplied to deposit physically developed silver and a stabilizing solution is supplied to carry out neutralization. A thin silver film is formed on the substrate by washing off the emulsion layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a lithographic printing plate precursor that can be handled in a bright room and that can perform heat mode laser writing.

[0002]

2. Description of the Related Art A lithographic printing plate comprises an oleophilic image portion which receives oil-based ink and an oil-repellent non-image portion which does not receive ink. Generally, the non-image portion comprises a hydrophilic portion which receives water. Have been. In normal lithographic printing,
Both water and ink are supplied to the plate, and the image area
The non-image area selectively receives water, and printing is performed by transferring the ink on the image area to a printing medium such as paper.

At present, a lithographic printing plate is manufactured by providing a lipophilic ink-receiving layer on a base material such as an aluminum plate, a zinc plate, or paper having a hydrophilized surface. Among these, a PS plate, which is made of a photosensitive material such as a diazo compound or a photopolymer on an aluminum base having a hydrophilic surface, or a silver complex salt on a paper or plastic support using silver halide as a photosensitive material. An image forming apparatus using a diffusion transfer method (DTR method) is generally used.

A method of forming an ink receiving layer (hereinafter referred to as an image layer) by using a diazo compound or a photopolymer is as follows. First, a photosensitive material such as a diazo compound or a photopolymer is formed on a substrate such as a metal plate, paper, a laminate, or an insulating substrate. Apply material. Next, the photosensitive material is irradiated with light to cause a chemical change to change the solubility in a developing solution. Photosensitive materials are classified into two types according to the type of chemical change. The light-irradiated part polymerizes and cures, so that the negative type becomes insoluble in the developer, and conversely, the functional group of the light-irradiated part changes to have solubility in the developer. It is a positive type. In either case, the photosensitive material remaining on the base material after processing with the developer and insoluble in the developer becomes an image layer.

On the other hand, a lithographic printing plate using the DTR method, particularly a lithographic printing plate having a physical development nucleus layer on a silver halide emulsion layer, is disclosed, for example, in US Pat. No. 134,769, No. 4,160,670,
Nos. 4,336,321 and 4,501,811
No. 4,510,228 and 4,621,04
No. 1, etc., the exposed silver halide crystal undergoes chemical development by DTR development to become black silver, forming a hydrophilic non-image portion. The crystals are converted into a silver salt complex by the complexing agent in the developing solution and diffuse to the physical development nucleus layer on the surface, and physical development is caused by the presence of the nucleus to form an image portion mainly composed of ink-receptive physical development silver. Form. A lithographic printing plate in which a physical development nucleus layer and a silver halide emulsion layer are sequentially coated on a grained and anodized aluminum-based support is described in, for example, JP-A-63-260491, JP-A-63-26049. −1161
No. 51, No. 4-282295 and the like. After the above lithographic printing plate is image-exposed and DTR-developed, the silver halide emulsion layer is washed with warm water to form an anodized aluminum base. An image portion mainly composed of physically developed silver is formed.

In the plate making process for making these printing plates, conventionally, an intermediate film or an underprint is prepared from characters, images and photographic originals, and these are collected to prepare an exposure film. Next, a contact exposure method using ultraviolet light or white light was mainly used. Further, a method has also been used in which a complete composition is produced by laminating the composition, and photographing is performed with a plate making camera. However, with the advancement of computers, laser direct writing methods that transmit digital signals from computer information to an exposure apparatus (computer-to-plate) and directly expose a photosensitive material using a laser can be performed. It has become The laser direct writing method has advantages such as low cost, high speed, and high productivity in a wide variety of small lot products because a plate-making film used in the middle can be omitted.

In order to cope with the laser direct writing method, a photosensitive material having high optical sensitivity is preferable. Since diazo compounds and photopolymers involve a photochemical reaction, the optical sensitivity is low, and is several to several hundred mJ / cm ² . Therefore, the laser output device must have a high output, and there are problems such as an increase in size of the device and an increase in cost.

On the other hand, in the case of forming an image by the DTR method using silver halide, the sensitivity is several μJ / cm ² and a simple semiconductor laser or the like allows sufficient exposure. Storage and application to a substrate must be performed in the dark or under a safe light, which has the disadvantage of significantly reducing the efficiency of production and plate making operations. Also, the reaction of a diazo compound or a photopolymer proceeds even under room light or sunlight, and the reactivity changes even at a high temperature. In addition, the presence of oxygen becomes an inhibitor of the reaction. Therefore, before exposure and development, dark room treatment and storage in a low oxygen state were similarly required.

Further, in the above-described image forming method, liquid processing such as using a developing solution is generally performed, and there is a disadvantage that processing of waste liquid is an environmental problem. 1
Since 995, the dumping of wastewater into the ocean has been banned, and the need for non-waste liquefaction and dry treatment has become a requirement of the times.

In order to meet such a demand, a lipophilic metal thin film is provided on a support having a hydrophilic surface, and the lipophilic metal thin film is irradiated with a high-output heat mode laser to remove heat by applying heat. Accordingly, a printing plate of a method of forming an image has been proposed. For example, JP-A-10-1
JP-A No. 80976 describes that a printing original plate having a silver thin film formed thereon by DTR development on a support having a hydrophilic layer can be subjected to heat mode laser exposure to perform plate making without performing development processing. it can. Japanese Patent Application Laid-Open No. 7-1848 discloses that a metallic silver layer and a hydrophobic layer having a thickness of less than 50 nm are formed on a metal silver layer on a support having a hydrophilic surface or provided with a hydrophilic layer. A heat mode recording material is disclosed, in which a printing original plate provided by applying a silver halide emulsion layer and performing DTR development is subjected to heat mode laser exposure.

In order to produce such a printing original plate, a silver salt diffusion transfer method is effective as a method for forming a silver thin film on a support. For such a method, refer to Japanese Patent Application No.
No. 215186. Among them, an effective method is to apply a silver halide emulsion layer as a silver complex salt donor on a support provided with a physical development nucleus layer, perform physical development treatment, and wash off the silver halide emulsion layer. There is a method of forming a silver thin film on a physical development nucleus.

[0012] However, although the methods disclosed therein disclose production in sheet form, they are not suitable for mass production. Further, in batch processing using a processor, there was a problem that the quality of the prepared lithographic printing plate precursor was remarkably varied due to liquid fatigue of the diffusion transfer developing solution, and stable performance was not obtained.

[0013]

SUMMARY OF THE INVENTION An object of the present invention is to provide a lithographic printing plate manufacturing technique which is used to produce a lithographic printing plate by removing a silver thin film by using a heat mode laser exposure. It is an object of the present invention to provide a method for producing a lithographic printing plate precursor capable of obtaining stable quality at a low temperature.

[0014]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, have found the following invention.

The method for producing a lithographic printing plate precursor according to the present invention comprises: 1. A physical development nucleus layer is provided on a web-like support having a hydrophilic surface or a hydrophilic layer, or a support having a surface active for physical development is selected. 2. coating a silver halide emulsion layer on the support; 3. Continuously supply a diffusion transfer developer to precipitate physically developed silver; After supplying the stabilizer and neutralizing, the emulsion layer was washed off; If necessary, a silver thin film is formed on the support by applying an overcoat layer.

According to a second aspect of the present invention, a method of manufacturing a lithographic printing plate precursor is characterized by applying the diffusion transfer developer.

According to a third aspect of the present invention, a method for producing a lithographic printing plate precursor comprises applying the silver halide emulsion layer, drying the silver halide emulsion layer, and then continuously applying a diffusion transfer developer. It is a feature.

In a fourth aspect of the present invention, a method of manufacturing a lithographic printing plate precursor according to the present invention is characterized in that the overcoat layer is a hydrophilic polymer layer having a thickness of 0.01 to 0.5 μm. .

According to a fifth aspect of the present invention, a method for producing a lithographic printing plate precursor is characterized in that the hydrophilic polymer layer contains 1 to 30% by weight of a hydrophobic compound.

[0020] In the sixth aspect of the present invention, the method for producing a lithographic printing plate precursor according to the sixth aspect is characterized in that the hydrophobic compound is a hydrophobic compound having a mercapto group and one or more hydrophobic substituents. Is what you do.

According to a seventh aspect of the present invention, there is provided a method of manufacturing a lithographic printing plate precursor, wherein the silver thin film layer has a particle size of 0.00
It is a layer composed of granular silver particles having a size of 5 to 0.2 microns.

In the eighth aspect of the present invention, the method for producing a lithographic printing plate precursor according to the present invention is characterized in that the diffusion transfer developer contains an amine compound.

According to the present invention, it is possible to mass-produce a lithographic printing plate precursor used for producing a lithographic printing plate by removing a silver thin film using heat mode laser exposure,
The quality can be stabilized. In addition, by using the lithographic printing original plate manufactured according to the present invention, the lithographic printing plate can be made by heating with a laser according to a desired image without using a liquid developer or equipment for processing the lithographic printing plate. Becomes possible. Further, it is possible to work in a bright room until the plate making process from the lithographic printing original plate and the printing process, and also it is possible to store for a long period of time in a bright room or under oxygen.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the form of a lithographic printing original plate manufactured according to the present invention will be described with reference to the drawings.

FIG. 1 is a schematic sectional view showing an example of a lithographic printing plate precursor according to the present invention when aluminum is used as a support.
The lithographic printing plate precursor (a) according to the present invention has an aluminum base 1
Has a roughened and anodized surface layer 2, a silver thin film 3 is provided thereon, and a hydrophilic polymer layer 4 is provided thereon. As a method for making a lithographic printing plate from the lithographic printing plate precursor produced by the present invention into a lithographic printing plate, first, the lithographic printing plate precursor (a) is irradiated with a laser so as to have a desired image (non-image area exposure). Here, the silver thin film 3 is removed by ablation by laser irradiation, or the adhesion to the aluminum surface is weakened, the silver thin film 3 is removed by means such as vacuuming, and a part of the upper hydrophilic polymer layer remains. The plate making is completed when the anodized surface layer 2 appears in this state. After that, if it is mounted on a lithographic printing press, the thin hydrophilic polymer layer in the image area is removed at the start of printing, and ink is applied to the remaining silver thin film 3 portion.
In the non-image area, water is received in the anodized surface layer 2 partially covered with the remaining hydrophilic polymer layer, and lithographic printing becomes possible.

Next, FIG. 2 shows an example of an apparatus for producing a lithographic printing original plate according to the present invention. On a web-like support having a hydrophilic surface or a hydrophilic layer, a physical development nucleus layer is provided in advance, or a web prepared to have a surface active for physical development. The support is unreeled from the unreeler section 11. An emulsion is coated on the support in an emulsion coating unit 12, and if necessary, dried by passing through a drying zone 13, and a diffusion transfer developer is supplied from a coating unit 14 to perform coating and development. next,
After neutralizing the solution by supplying a stabilizing solution in section 15, the emulsion layer was
Wash off and remove in part 6 and, if necessary,
After gumming is performed in the overcoating liquid application unit 17 and squeezed by the roll 18, it is dried through the drying zone 19 and wound up by the reeler unit 20.

In the present invention, it is necessary that the support has a hydrophilic surface or that a hydrophilic layer is provided on the support. This hydrophilic surface or hydrophilic layer functions when the upper layer is removed by ablation and the hydrophilic surface is exposed. That is, the fountain solution receives a dampening solution at the time of lithographic printing and creates a portion where ink is not applied.

As the support used in the lithographic printing plate precursor according to the present invention, paper, various films, plastics, paper coated with a resin-like substance, metal, and those obtained by laminating a polyester film or paper on these can be used.

In the present invention, an aluminum base which has been roughened and anodized is preferred. It has good hydrophilicity and good surface activity,
The silver film thus produced is particularly preferable because it can be removed by laser exposure and is strongly adhered to the aluminum surface to impart surface activity with excellent printing durability.

As the aluminum plate used for the support according to the present invention, pure aluminum and various metals, for example,
An aluminum alloy plate containing a small amount of silicon, magnesium, iron, copper, zinc, manganese, chromium, titanium or the like is suitable. A trace amount of impurity metal contained in aluminum or a small amount of metal added arbitrarily has a large effect on the size, shape and distribution of pits obtained by electrolysis, and also on the strength of the aluminum plate give.

The aluminum plate is preferably subjected to a surface treatment in order to be used as a support for an offset printing plate.
In the surface treatment, generally, degreasing, roughening, desmutting, and anodizing are performed, and the treatment is continuously performed using an aluminum coil. After each treatment, if necessary, washing is performed, and the support is dried to obtain a support.

The aluminum treatment process is described in
The method is described in detail in Japanese Patent Publication No. 244775, and a roughened and anodized aluminum base is manufactured by using the method described therein.

For example, as described in JP-A-10-244775, in the case of an aluminum support for an offset printing plate, the anodic oxide film is exposed to the outermost surface as it is in the final step of anodic oxidation. It is presumed that the denatured layer formed by the treatment immediately before the anodic oxidation is present on the surface of the oxide film. The properties of these modified layers are expected to have a significant effect when forming a silver thin film. However, in existing PS plates and OPC printing plates, the photosensitive layer is usually formed by organic solvent-based coating. Therefore, the influence of these modified layers hardly appears. However, when the adhesion between the silver thin film and the aluminum surface greatly affects the printing durability as in the present invention, the influence of these modified layers appears. The chemical treatment such as desmut treatment immediately before anodization is preferably an acidic treatment solution, and particularly preferably a treatment solution containing nitric acid.

In the present invention, desmutting is an important step in the aluminum-based surface treatment. The aluminum sheet strip subjected to the electrolytic surface roughening treatment is sufficiently washed with water, but the surface thereof is usually covered with smut, and cannot be removed only by washing with water, but closes the pits. In order to remove the smut, a desmutting process is performed. In the desmut treatment, the smut dissolves and a pit surface appears. The amount of dissolution varies depending on the treatment conditions with the electrolytic solution.
1 to 1 g / m ² is appropriate.

In the desmut treatment, an alkali agent such as sodium hydroxide used for the degreasing treatment, or phosphoric acid, sulfuric acid,
Acids such as nitric acid and perchloric acid, or a mixture thereof can be used, but each has a different smut removing ability, and the removing ability is adjusted according to the type of treatment solution, its concentration, or the treatment temperature. If the desmutting treatment is too strong, the unevenness formed in the roughening step is dissolved to make it flat, and if the desmutting treatment is too weak, the smut remains unpreferably. The remaining smut remains even after the anodic oxidation treatment and causes an abnormal point when forming a silver thin film.

The desmut treatment with the acidic processing solution used in the present invention provides a surface activity capable of producing a preferable physically developed silver. In particular, an acid processing solution containing nitric acid is preferable, and the developed image silver has good adhesiveness, so that a printing plate having high printing durability can be produced. When it is difficult to remove the smut with the acid treatment liquid, a desmut treatment in which the influence of the desmut by the alkali does not remain can be achieved by, for example, a two-step treatment in which the desmut is treated with an alkali and then further treated with an acid treatment liquid.

The roughened and desmutted aluminum strip is then anodized. The anodic oxidation treatment is performed by a known method, for example, as described in JP-A-10-244775.

In the present invention, when the surface does not become hydrophilic, a hydrophilic layer can be formed and used. Examples of the hydrophilic polymer for forming such a hydrophilic layer include the following examples. These can be used in combination of two or more types in view of printing performance such as background stain resistance and printing durability.

Examples of natural products include those obtained from algae such as starches, seaweed mannan, agar and sodium alginate; vegetable mucilage such as mannan, pectin, tragacanth gum, karaya gum, xanthin gum, guabing gum, locust bingham, gum arabic; Dextran,
Glucan, xanthan gum, and homopolysaccharides such as levan, succinoglucan, pullulan, curdlan, and microbial mucilage such as heteropolysaccharides such as xanthan gum, glue, gelatin, proteins such as casein and collagen, chitin and its derivatives and the like. No.

Also, as semi-natural products (semi-synthetic products),
Examples include cellulose derivatives, modified gums such as carboxymethyl guar gum, and modified starches such as baked starches such as dextrin, oxidized starches, and esterified starches.

Synthetic products include polyvinyl alcohol, partially acetalized polyvinyl alcohol, allyl-modified polyvinyl alcohol, modified polyvinyl alcohol such as polyvinyl methyl ether, polyvinyl ethyl ether and polyvinyl isobutyl ether, polyacrylate, and polyacrylate. Compound, polymethacrylate,
And polyacrylic acid derivatives such as polyacrylamide and polymethacrylic acid derivatives, polyethylene glycol,
Examples include polyethylene oxide, polyvinylpyrrolidone, vinylpyrrolidone / vinyl acetate copolymer, carboxyvinyl polymer, styrene / maleic acid copolymer, and styrene / crotonic acid copolymer.

When gelatin is used for the hydrophilic layer, it can be cured with a gelatin hardener. Gelatin hardeners include, for example, inorganic compounds such as chrome alum,
Aldehydes such as formalin, glyoxal, malealdehyde and glutaraldehyde, N-methylal compounds such as urea and ethylene urea, mucochloric acid, 2,3-
Aldehyde analogs such as dihydroxy-1,4-dioxane, 2,4-dichloro-6-hydroxy-S-
Triazine salts, 2,4-dihydroxy-6-chloro-
Compounds having an active halogen such as S-triazine salt, divinyl sulfone, divinyl ketone, N, N, N-
One or two of various compounds such as triacryloylhexahydrotriazine, compounds having two or more active three-membered ethyleneimino groups or epoxy groups in a molecule, and dialdehyde starch as a polymer hardener. More than one species can be used.

The hydrophilic layer of the lithographic printing plate according to the present invention may contain an inorganic sol such as titania, colloidal silica, alumina sol, zirconia sol and the like for the purpose of preventing the printing background stain. Can also be contained. The proportion to be contained is appropriately determined in a desired range depending on various conditions such as printing ink and fountain solution used for printing, printing speed and printing pressure.

In order to coat the hydrophilic layer of the lithographic printing plate according to the present invention, some of anionic, cationic or nonionic surfactants may be used as an auxiliary, and a matting agent, Thickeners, antistatic agents and the like can also be used.

In the present invention, a physical development nucleus layer is provided on a web-like support having a hydrophilic surface or a hydrophilic layer, or a support having a surface active for physical development. It is necessary to choose a body.

In the present invention, the physical development nucleus layer is provided by applying a coating solution containing physical development nuclei. The coating solution contains a physical development nucleus and, if necessary, a hydrophilic polymer. As physical development nuclei, silver, antimony, bismuth, cadmium, cobalt, lead, nickel, palladium, rhodium, gold, platinum and other metal colloid fine particles, and sulfides, polysulfides, selenides of these metals, or those It may be a mixture or a mixed crystal. The physical development nucleus may or may not contain a hydrophilic polymer. Examples of the hydrophilic polymer include gelatin, starch, dialdehyde starch, carboxymethylcellulose, gum arabic, sodium alginate, hydroxyethylcellulose, and polystyrenesulfonic acid. , Poly (sodium acrylate), copolymer of vinylimidazole and acrylamide,
There is a copolymer of acrylic acid and acrylamide, hydrophilic polymers such as polyvinyl alcohol or oligomers thereof,
Its content is preferably 0.5 g / m ² or less. Further, the physical development nucleus layer may contain a developing agent such as hydroquinone, methylhydroquinone, or catechol, or a known hardener such as formalin or dichloro-s-triazine.

In the present invention, the physical development nucleus layer is provided between the support and the silver halide emulsion layer.

In the present invention, instead of providing a physical development nucleus layer, a support having a surface active for physical development can be selected. A preferred support used for such a purpose is a roughened and anodized aluminum base having good surface activity described in Japanese Patent Application No. 9-304390, The surface activity is determined by using the following physical developer 1 at 23.degree.
It is capable of producing 0.5 g / m ² or more of physically developed silver by subjecting to separate processing.

[0049]

The aluminum base having such an active surface can be obtained by an aluminum surface treatment, and an important step for obtaining the aluminum base is the desmut treatment with the above-mentioned acidic treatment solution. In particular, an acidic processing solution containing nitric acid is preferable because of its high surface activity, and can produce preferable physical developed silver without providing a physical development nucleus layer.

In the present invention, a physical development nucleus layer is provided on a web-like support having a hydrophilic surface or a hydrophilic layer, or a support having a surface active for physical development. It is necessary to select a body and coat the silver halide emulsion layer on the support.

As the silver halide used in the present invention, known silver halides are used, and examples thereof include silver chloride, silver bromide, silver chlorobromide, and silver iodide. Used in Silver halide crystals are rhodium salts, iridium salts, palladium salts, ruthenium salts,
It may contain heavy metal salts such as nickel salts and platinum salts,
The addition amount is from 10 ^-8 to 10 ^-3 mol per mol of silver halide. The crystal form of the silver halide is not particularly limited, and may be cubic to tetradecahedral grains, or core-shell or tabular grains. The silver halide crystal may be a monodisperse or polydisperse crystal, and the average grain size is 0.2 to 0.8 μm.
Range. One preferred example is a monodispersed or polydispersed crystal containing 80 mol% or more of silver chloride, which contains a rhodium salt or an iridium salt. Further, additives such as an antifoggant, a stabilizer and a surfactant may be contained by a known method. For details of the photosensitive silver halide emulsion and a method for producing the same, reference can be made to the items described in JP-A-49-55402.

In the present invention, following the emulsion coating,
It is necessary to supply a diffusion transfer developer to precipitate physically developed silver, supply a stabilizer, neutralize the emulsion, and then wash off the emulsion layer to form a silver thin film on the support. The term “continuous” as used in the present invention means that the application of the diffusion transfer developer continues without winding the web after the emulsion is applied.

In the present invention, it is preferable to apply a diffusion transfer developer. For application, the viscosity and surface tension of the diffusion transfer developer need to be set in appropriate ranges, and known coating techniques can be applied. It has been found that the method of applying the diffusion transfer developer is superior in the efficiency of removing the silver thin film (hereinafter, referred to as ablation suitability) as compared with the method of dipping in a tank, which is used in a normal processor. The preferred coating amount of the diffusion transfer developer is
Although it varies depending on its concentration, etc., it is usually 50 ml / m
^Two or more are preferred.

Further, it is preferable that after the emulsion coating, the emulsion layer is once dried and then a diffusion transfer developer is applied. It was found that drying once was superior in ablation suitability as compared with the case where the diffusion transfer developer was applied without drying the emulsion layer.

The developing solution for preparing a silver thin film used in the present invention includes an alkaline substance for adjusting pH, for example, an acidic substance such as sodium hydroxide, potassium hydroxide, lithium hydroxide and sodium tertiary phosphate. Substances such as sulfuric acid, nitric acid, phosphoric acid, etc., sulfites as preservatives, silver halide solvents such as thiosulfate, thiocyanate, cyclic imide, 2-mercaptobenzoic acid, amines, etc., thickeners such as hydroxy Ethyl cellulose, carboxymethyl cellulose, etc., antifoggants such as potassium bromide, development modifiers such as polyoxyalkylene compounds,
Onium compounds and the like can be included. Further, as the developing solution, a compound or the like which improves the ink running of the silver thin film on the surface as described in US Pat. No. 3,776,728 can be used. Furthermore, to neutralize the gelatin at the time of wash-off after neutralization with the stabilizer,
As the precipitant, a known hydrophilic polymer, for example, a polystyrene sulfonate polymer or the like can be used.

As the stabilizing solution used in the present invention, generally used buffers, preservatives, preservatives, wetting agents, ink riding accelerators, surfactants and the like can be mixed. For example, as a buffer, an inorganic acid such as phosphoric acid or sulfuric acid, or an organic acid such as succinic acid or propionic acid is used to adjust the pH to 5-7.
To keep it. Further, complexing agents such as iminodiacetic acid and ethylenediaminetetraacetic acid can be mixed. As the ink riding accelerator, the above-mentioned U.S. Pat.
There are compounds described in the specification of US Pat. Also, inorganic fine particles such as colloidal silica can be mixed in a range that does not inhibit the action of the compound having a mercapto group or the like.

The overcoat layer provided as necessary in the present invention is an overcoat layer containing a hydrophilic polymer as a main component, as described in Japanese Patent Application No. 10-2115186. The hydrophilic polymer layer that is installed has light transmittance in the infrared spectral region, and when exposed with a heat mode laser,
It does not lower the sensitivity, and also serves to prevent the laser irradiation part from being hydrophobized. The hydrophilic polymer used in the present invention may be a natural product such as mannan, pectin, tragacanth gum, karaya gum, xanthin gum, guar gum, locust bingham, gum arabic or other plant mucilage, dextran, glucan, xanthan gum, or levan. Microbial mucus such as polysaccharides, heteropolysaccharides such as succinoglucan, pullulan, curdlan, and xanthan gum, and the like.

Also, as semi-natural products (semi-synthetic products),
Examples include cellulose derivatives, modified gums such as carboxymethyl guar gum, and baked starches such as dextrin.

Synthetic products include polyvinyl alcohol, partially acetalized polyvinyl alcohol, allyl-modified polyvinyl alcohol, modified polyvinyl alcohol such as polyvinyl methyl ether, polyvinyl ethyl ether and polyvinyl isobutyl ether, polyacrylate, and polyacrylate. And polyacrylic acid derivatives, polyethylene glycol, polyethylene oxide, polyvinylpyrrolidone, vinylpyrrolidone / vinyl acetate copolymer and the like.

The thickness of the hydrophilic polymer layer to be set is 0.1 mm.
01-0.5 microns is preferred. Its thickness is 0.
If less than 01 micron, there is little effect on dirt,
If it exceeds 0.5 micron, there is a disadvantage that the ink application of the image area is delayed.

In the present invention, the hydrophilic polymer layer preferably contains 1 to 30% by weight of a hydrophobic compound. The silver particles of the present invention are ink-receptive and have the property that ink can be applied alone. However, by including a hydrophobic compound in the hydrophilic polymer layer, the ink application can be stabilized.

Examples of the hydrophobic compound used in the present invention include known oils such as phthalate esters such as diethyl phthalate and dibutyl phthalate, and phosphate esters such as tricresyl phosphate, and various animal oils and vegetable oils. Can be done. Mercaptotetrazole derivatives having a hydrophobic group such as phenylmercaptotetrazole are also effective.

Among the hydrophobic compounds used in the present invention, those having a mercapto group and one or more hydrophobic substituents are preferred. Examples of such a hydrophobic compound include a mercaptotetrazole derivative such as phenylmercaptotetrazole, a mercaptotriazole derivative represented by the following general formula 1, a mercaptooxadiazole derivative represented by the following general formula 2, and the like. .

[0065]

Embedded image

[0066]

Embedded image

In the formula, R ₆ is an alkyl group, an aryl group or an aralkyl group, and R ₇ is a hydrogen or an acyl group.
Preferably, R ₆ is an alkyl group containing 3 to 16 carbon atoms.

Further, such hydrophobic compounds include:
Compounds that impart ink receptivity are also preferred, for example, JP-B-48-29723, U.S. Pat. No. 3,721,5.
No. 59, etc.

In the present invention, the hydrophilic polymer layer containing the hydrophobic compound is formed by forming a silver thin film and then applying it. The hydrophobic compound may be added to the hydrophilic polymer aqueous solution using a known oil dispersion technique, or may be added to the hydrophilic polymer aqueous solution after being dissolved in an appropriate solvent. Compounds having a mercapto group and one or more hydrophobic substituents are described in JP-A-6-79982 and JP-A-7-2486.
It can also be dissolved using the amine compound described in JP-A No. 30 and added to the hydrophilic polymer.

In the present invention, the average particle size is 0.1.
Silver thin films consisting of silver particles of 005 to 0.2 microns are preferred. Such a silver thin film composed of silver particles is easily removed by heat mode laser exposure, and has excellent printability. A silver thin film composed of silver particles having an average particle size of more than 0.2 micron or a vacuum thinned silver thin film having a particle size of less than 0.005 micron is hard to get ink on.
The image quality of printed matter deteriorates.

In order to prepare a silver thin film composed of such granular silver particles, the developing method using the diffusion transfer developer of the present invention is effective. The average grain size of the silver grains formed by this method is determined by the layer composition of the plate, the halogen composition of the silver halide emulsion, the average grain size of the emulsion grains, plate components such as a development inhibitor, a developing agent, and a silver halide. It depends on the components of the diffusion transfer developing solution such as a solvent and a development inhibitor, and the conditions of the diffusion transfer development processing. These factors are described, for example, in US Pat. No. 3,728,11.
No. 4, No. 4,134,769, No. 4,160, 6
No. 70, No. 4,336,321, No. 4,501
Nos. 811 and 4,510,228 and 4,62
No. 1,041, JP-A-63-260491, JP-A-3-116151 and JP-A-4-282295. 0.00 of silver particles constituting the silver thin film
Controlling between 5 and 0.2 microns is achieved by optimizing these known techniques.

As a method for measuring the particle size of the silver particles constituting the silver thin film, a photograph is taken with an electron microscope, the size of each silver particle is measured from the photograph, and the average value is calculated. . As a simple method, an average particle may be picked up and its particle size may be measured.

In the method of making a lithographic printing plate precursor according to the present invention, ablation suitability (that is, the sensitivity of the lithographic printing plate precursor in the method of the present invention) depends on the thickness of a silver thin film. I do. Therefore, it is preferable to determine the thickness of the silver thin film based on the laser output used for drawing. If the output is 1 W or more, the thickness can be set thicker. If the output is less than 1 W, it is preferable to set the thickness in the range of 0.05 μm to 5 μm.

In the present invention, by including an amine compound in the diffusion transfer developer, a silver film having more excellent ablation suitability can be formed. The silver thin film produced in this way exhibits further excellent ink receptivity. The amine compound used in the present invention is a compound substituted with ammonia, a substituted or unsubstituted saturated or unsaturated alkyl group, cycloalkyl group, alkoxy group, aryl group, alkanoyl group, aroyl group, or heterocyclic group. And these substituents may be bonded to each other to form a ring.

Specific examples are shown below, but the present invention is not limited to these examples.

[0076]

Embedded image

These amine compounds are used in an amount of 0.1 to 100 times, more preferably 1 to 50 times, the molar number of silver ions.

As the light absorber, generally, any dye or pigment may be used, and examples thereof include carbon black, cyanine, metal-free or metal phthalocyanine, metal dithiolene, and anthraquinone.

When a light absorbing agent is contained in the roughened and anodized aluminum base, a chemical or electrochemical metal coloring method, which is generally called black dyeing, can be used. By dyeing an organic or inorganic dye by immersion dyeing, the dye can be introduced into the fine pores of the anodic oxide film, followed by sealing treatment to dye.

Further, on the back surface of the support, a layer containing a matting agent or an antistatic agent may be provided in consideration of transportability in a drawing apparatus or the like.

In the method of making a lithographic printing original plate according to the present invention, the laser used for exposing the anodized surface includes a carbon dioxide laser, a nitrogen laser, an Ar laser, a He / Ne laser, a He / Cd laser, and a Kr laser. Gas laser such as laser, liquid (dye) laser, ruby laser, solid laser such as Nd / YAG laser, GaAs / G
aAlAs, semiconductor laser such as InGaAs laser, K
An excimer laser such as an rF laser, a XeCl laser, a XeF laser, and Ar ₂ can be used.

[0082]

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist of the invention.

Example 1 An A1050 type aluminum plate strip having a width of 300 mm and a thickness of 0.2 mm was moved at a processing speed of 1.3 m / min, immersed in a 4% aqueous sodium hydroxide solution at 50 ° C. for 30 seconds, and washed with water. , The electrolytic cell of the indirect power supply system is filled with 1.5% hydrochloric acid at 20 ° C., and the power supply is set to 20 A / dm ² , 50
Hz, a single-phase alternating current of 60 Hz is applied for 60 seconds to roughen the AC electrolytic surface, rinse with water, then immersed in a 6% nitric acid aqueous solution at 60 ° C. for 30 seconds, desmutted, washed with water, and then 25 ° C., 20%
It was passed through sulfuric acid for 60 seconds, anodized with a direct current of 5 A / dm ² , washed with water, and then dried to obtain a web-shaped aluminum base for offset printing plates (aluminum base 1).

The nucleus coating solution described in Example 2 of JP-A-53-21602 (a hydrophilic polymer No. 1) was prepared on the web-like aluminum base thus produced.
4 mg of copolymer of acrylamide and imidazole
/ M ² ), dried and wound up.

The aqueous solution of inert gelatin was kept at 60 ° C.
By adding a mixed aqueous solution of sodium chloride and potassium bromide (29.5 mol% of potassium bromide) and an aqueous solution of silver nitrate at the same time with vigorous stirring, an average particle size of 0.2
An 8 μm silver chlorobromide emulsion was prepared, and potassium iodide corresponding to 0.5 mol% / 1 mol Ag was added to replace the surface. The silver halide emulsion was composed of 70% silver chloride and 29% silver bromide.
90% of all grains consisting of 5% and 0.5% silver iodide.
Emulsion coating liquid 1 having a gelatin concentration of 7% was prepared using a monodispersed silver chloroiodobromide emulsion having a weight% within ± 30% of the average grain size, and kept at 35 ° C.

Next, the following diffusion transfer developer 1 was prepared,
It was kept at 23 ° C.

<Diffusion Transfer Developer 1> Sodium hydroxide 25 g Sodium sulfite 100 g Hydroquinone 25 g 4-Hydroxymethyl-4-methyl-1-phenyl-3-pyrazolidone 4 g Sodium ethylenediaminetetraacetate 8 g Sodium thiosulfate 8 g N-methylethanolamine 50g Carboxymethylcellulose 5g Glycerin 40g Add water 1,000ml

Further, the following Stabilizing Solution 1 was prepared and kept at 35 ° C.

<Stabilizing Solution 1> Potassium phosphate 40 g 5 g Sodium ethylenediaminetetraacetate 5 g

Further, the following overcoat liquid was prepared and kept at 23 ° C.

<Overcoat Liquid 1> Sodium ethylenediaminetetraacetate 5 g 2-mercapto-5-n. Heptyl-oxa-3,4-diazole 0.2 g Triethanolamine 2 g Gum arabic 5 g 85% phosphoric acid 1 g Add water 1,000 ml

A silver thin film was prepared using the apparatus shown in FIG. The web-form aluminum base coated with the physical development nucleus layer was unreeled from 11, and the emulsion coating solution 1 was applied from 12 to 3 g / g in terms of silver nitrate.
m ² , gelatin 3 g / m ² , wet coating amount 43 g /
m ² ), once dried through the drying zone 13,
In step 14, the diffusion transfer developer 1 is applied at a coating amount of 100 ml / m ² , and after transporting for 45 seconds, the stabilizer 1 is dropped in a shower form from 15 and the emulsion layer is washed with 16 rolls wrapped with a Molton cloth. It was turned off, the topcoat liquid was applied at 17, squeezed at 18, and dried at a coating amount of 15 g / m ² through the short drying zone 19 and wound up at 20. When the silver thin film thus produced was photographed with a scanning electron microscope, it was found that the silver thin film was composed of granular silver particles, and the average particle size was measured. It was in the range of 0.2 microns.

The lithographic printing original plate 1 of the present invention thus produced had a uniform silver thin film with almost no development unevenness. The lithographic printing original plate 1 was exposed to an 8W YAG laser having a wavelength of 1064 nm to ablate granular silver particles to obtain a lithographic printing plate 1.

For comparison, the emulsion was coated, dried and wound up.
The sheet was cut, and the above-mentioned diffusion developer 1 was mixed with Agfa silver squirrel processor SLT-85N for 2 seconds.
Treatment was performed at 3 ° C. for 25 seconds at 33 ° C. using the above Stabilizing Solution 1, washed off, and gummed using the above Overcoating Solution 1. When the silver thin film thus produced was photographed with a scanning electron microscope, it was found that the silver thin film was composed of granular silver particles, and the average particle size was measured. It was in the range of 0.2 microns.

The comparative lithographic printing plate precursor a produced in this manner had uneven development and uneven gum application. The lithographic printing plate precursor a was exposed to an 8 W YAG laser having a wavelength of 1064 nm to ablate granular silver particles to obtain a lithographic printing plate a.

The lithographic printing plates 1 and a thus obtained were mounted on an offset printing machine (diamond 3H manufactured by Mitsubishi Heavy Industries, Ltd.), and a plate surface water supply system (AD mode) was used.
Printing was performed using a dampening solution obtained by adding 2% of isopropyl alcohol to Astromark III 2% manufactured by Niken, and using N type GEOS-G black manufactured by Dainippon Ink Co., Ltd. as the ink. The lithographic printing plate a was found to have a light, uneven stain. Therefore, after removing the ink using a plate cleaner, applying a gum solution and restarting the printing plate a, a printed matter free of dirt was obtained. On the other hand, for the lithographic printing plate 1, a printed matter free of stains was obtained from the start. Also,
Lithographic printing plate 1 was also excellent in uniformity of ink application at the start, and stable quality was obtained. In addition, 30
It was confirmed that a uniform silver thin film was obtained also in the flow direction of the coated product of m.

Example 2 A lithographic printing original plate 2 was prepared in the same manner as in Example 1 except that the air was passed through the drying zone 13 without sending air without drying. When the silver thin film thus produced was photographed with a scanning electron microscope, it was found that the silver thin film was composed of granular silver particles, and the average particle size was measured. It was in the range of 0.2 microns.

The lithographic printing original plate 2 was exposed to an 8 W YAG laser having a wavelength of 1064 nm to ablate granular silver particles to obtain a lithographic printing plate 2. The lithographic printing plate 2 showed yellow stain in the non-image area as compared with the lithographic printing plate 1, and the same printing test as in Example 1 was performed. Although there was
It was recognized that the water width was rather narrow and the soil tended to be dirty.

Example 3 A lithographic printing original plate 3 was prepared in the same manner as in Example 1 except that the overcoat liquid 1 was not applied. When the silver thin film thus produced was photographed with a scanning electron microscope, it was found that the silver thin film was composed of granular silver particles, and the average particle size was measured.
It was in the range of 0.2 microns.

The lithographic printing plate precursor 3 was exposed to an 8 W YAG laser having a wavelength of 1064 nm to ablate granular silver particles to obtain a lithographic printing plate 3. When a printing test similar to that of Example 1 was performed, the ink application was slower than that of the lithographic printing plate 1, and although 50 pieces of waste paper were output, a good printed matter was obtained thereafter.

Example 4 Thickness 17 having 0.04 g / m ² gelatin subbing layer
On one side of 5μm of PET (polyethylene terephthalate) film to form a coated hydrophilic layer so that the zirconia sol 0.5 g / m ² and polyvinyl alcohol 0.1 g / m ^2, and heated, firmly the coating did.

On the web-like PET base having a hydrophilic layer thus produced, JP-A-53-2160 was used.
The nucleus coating solution described in Example 2 of Japanese Patent Publication No. 2 (containing 4 mg / m ² of a copolymer of acrylamide and imidazole of No. 3 as a hydrophilic polymer) was applied, dried and wound up.

Thereafter, in the same manner as in Example 1, a silver thin film was produced using the apparatus shown in FIG. The web-form PET base coated with the physical development nucleus layer was unreeled from 11, and the emulsion coating solution 1 was applied from 12 (3 g / m ² in terms of silver nitrate, gelatin 3 g / m ² ,
The wet transfer amount is 43 g / m ² ), and once dried through the drying zone 13.
After applying at a coating amount of 00 ml / m ^{2 and} transporting for 45 seconds,
The stabilizing solution 1 was dropped from 5 into a shower, and the emulsion layer was washed off with 16 rolls wrapped with a Molton cloth.
Apply the top coat liquid at 7, squeeze at 18, and apply 15 g / m
The coating amount of ² was dried through a short drying zone 19 and wound up at 20. When the silver thin film thus produced was photographed with a scanning electron microscope and photographed of the silver thin film, it was found that the silver thin film was composed of granular silver particles, and the average particle size was measured. It was in the range of 0.2 microns.

The lithographic printing original plate 4 of the present invention produced in this manner had a uniform silver thin film with almost no development unevenness. The lithographic printing original plate 4 was exposed to an 8 W YAG laser having a wavelength of 1064 nm to ablate granular silver particles to obtain a lithographic printing plate 4.

This lithographic printing plate 4 was mounted on an offset printing machine (Ryobi Magics Co., Ltd., 3200MCD), and an etchant (SLM-OH, manufactured by Mitsubishi Paper Mills) was applied thereto. When printing was performed using the new champion ink N manufactured by Ink Company,
No stain occurred even on the 00 sheets, and a printed matter having excellent print quality was obtained.

[0106]

As described above, by using the method for producing a lithographic printing plate precursor of the present invention, a lithographic printing plate precursor used for producing a lithographic printing plate by removing a silver thin film using laser exposure in a heat mode. Has the effect that mass production is possible and stable quality can be obtained. The plate making of the lithographic printing plate precursor manufactured according to the present invention can be performed even in a bright room, and the working environment is very good because no developing solution is used. In addition, it is possible to cope with a direct drawing method using a laser, to obtain an image having high resolution at low cost, and to provide an excellent effect of having excellent printability.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram illustrating an example of a lithographic printing original plate manufactured using the present invention.

FIG. 2 is a conceptual diagram illustrating an example of a manufacturing apparatus for implementing the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Aluminum base 2 Surface layer roughened and anodized 3 Silver thin film 4 Hydrophilic polymer layer 11 Unreeler part 12 Emulsion coating part 13 Drying zone 14 Diffusion transfer developer coating part 15 Stabilizing solution supply part 16 Emulsion wash off For roller 17 Top coat liquid application section 18 Squeeze roller 19 Drying zone 20 Reeler section

Continued on the front page (72) Inventor Takayuki Nakamura 3-4-2 Marunouchi, Chiyoda-ku, Tokyo F-term in Mitsubishi Paper Mills Co., Ltd. (Reference) 2H096 AA06 AA09 BA09 BA20 CA20 EA04 EA23 GA43 2H114 AA04 AA14 BA01 BA05 DA05 DA06 DA31 DA32 DA75 GA27 GA28 GA34 GA38

Claims (8)

[Claims] 1. A method for producing a lithographic printing plate precursor for producing a lithographic printing plate by removing a silver thin film using laser exposure in a heat mode, comprising: 1. A physical development nucleus layer is provided on a web-like support having a hydrophilic surface or a hydrophilic layer, or a support having a surface active for physical development is selected. 2. coating a silver halide emulsion layer on the support; 3. Continuously supply a diffusion transfer developer to precipitate physically developed silver; After supplying the stabilizer and neutralizing, the emulsion layer was washed off; A method for producing a lithographic printing original plate, comprising forming a silver thin film on the support by applying an overcoat layer as needed. 2. The method for producing a lithographic printing original plate according to claim 1, wherein the diffusion transfer developer is applied. 3. The lithographic printing plate precursor according to claim 1, wherein the silver halide emulsion layer is coated and dried, and then a diffusion transfer developer is continuously applied. Production method. 4. The method according to claim 1, wherein the overcoat layer is a hydrophilic polymer layer having a thickness of 0.01 to 0.5 μm. 5. The method according to claim 4, wherein the hydrophilic polymer layer contains 1 to 30% by weight of a hydrophobic compound. 6. The method for producing a lithographic printing original plate according to claim 5, wherein the hydrophobic compound is a hydrophobic compound having a mercapto group and one or more hydrophobic substituents. 7. The silver thin film layer has a particle size of 0.005.
5. The method for producing a lithographic printing original plate according to claim 1, wherein the layer is composed of granular silver particles having a particle size of 0.2 to 0.2 microns. 8. The method according to claim 1, wherein the diffusion transfer developer contains an amine compound.
A method for producing a lithographic printing original plate according to claim 7.