JPH10123726A - Image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a polymer image having sufficient mechanical strength by using less energy. SOLUTION: An image forming material successively provided with an image forming layer 12 contg. polymer and a photosensitive layer 13 contg. a silver halide, reducing agent and ethylenic unsatd. polymerizable compd. on a base 11 is first subjected to image exposure. Next, the exposed part 21 of the photosensitive layer 12 is cured by heating the image forming material. Liquid contg. a reactive material which reacts with the polymer is then applied on the image forming material, thereby passing the non-exposed parts 22 of the photosensitive layer 13 and penetrating down to the image forming layer 12. The reactive material and the polymer come into reaction with each other, thereby, the polymer of the non-exposed part 22 is denatured. Next, the non-exposed part (or exposed part) of the image forming layer 12 and the photosensitive layer 13 are eluted by using an eluting liquid.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for forming an image using silver halide as a light sensor.

[0002]

2. Description of the Related Art A photosensitive material which forms a cured image by heat development using silver halide as an optical sensor is disclosed in Japanese Patent Application Laid-Open No. 61-1 / 1986.
83640 and 61-188535. In these photosensitive materials, a photosensitive layer containing a silver halide, a reducing agent and a polymerizable compound is provided on a support. When the photosensitive material is image-exposed and thermally developed,
The silver halide is developed to generate free radicals, which polymerize the polymerizable compound to form a polymer image. JP-A-61-188535 describes that the obtained polymer image can be used as a printing plate. However, the polymer image had insufficient mechanical strength, and had insufficient printing durability as a printing plate. Furthermore, the printing ink receptivity (filling property) of the polymer image is
There is also a problem that it is insufficient. In the above method, the polymerizable compound in the exposed area is polymerized. JP-A-61-260241
In Japanese Patent Application Laid-Open Publication No. H10-209, there is a description of an image forming method in which a polymerizable compound in an unexposed portion is polymerized. In the method described in the publication, the oxidant uses a reducing agent having a polymerization inhibiting action, and while suppressing the polymerization of the polymerizable compound in the exposed part, the polymerizable compound in the unexposed part is controlled using a thermal polymerization initiator. Is polymerized.

A photosensitive material suitable for using an image for a printing plate is disclosed in JP-A-5-249667 and JP-A-4-19185.
No. 6, each publication. These photosensitive materials are
On a support, a curable layer containing a polymerizable compound and a hydrophobic polymer (preferably, a polymer having an acidic group and a crosslinkable group), and a hydrophilic photosensitive layer containing silver halide (and an overcoat layer) Is provided. When these photosensitive materials are exposed to light and thermally developed, the silver halide is developed to generate free radicals, and the polymerizable compound is polymerized or the crosslinkable polymer is crosslinked, whereby the curable layer is cured and the polymer image is cured. Is formed. When a polymer image is used as a printing plate, the uncured curable layer (non-image portion) is coated with a solvent (eg, an alkaline solution).
Use the remaining polymer image after elution removal. This image is hydrophobic and has sufficient inking properties and mechanical strength.
However, in order to obtain a polymer image having sufficient mechanical strength, it is necessary to carry out thermal development at a high temperature for a long time until the curable layer is sufficiently cured.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method capable of forming a polymer image having sufficient mechanical strength with the use of low energy.

[0005]

The object of the present invention has been attained by the following image forming methods (1) and (2). (1) A step of image-exposing an image-forming material in which an image-forming layer containing a polymer and a photosensitive layer containing a silver halide, a reducing agent and an ethylenically unsaturated polymerizable compound are sequentially provided on a support; Heating the forming material to cure the exposed portion of the photosensitive layer; applying a liquid containing a reactive substance that reacts with the polymer to the image forming material, whereby the reactive substance passes through the unexposed portion of the photosensitive layer Permeate to the image forming layer and react with the reactive substance and the polymer, thereby denaturing the unexposed portion of the polymer to be soluble in the eluate; An image forming method, comprising a step of forming an image composed of an unexposed portion and a photosensitive layer, thereby forming an image including a remaining image forming layer.

(2) Image-exposing an image-forming material in which an image forming layer containing a polymer and a photosensitive layer containing a silver halide, a reducing agent and an ethylenically unsaturated polymerizable compound are sequentially provided on a support. Heating the image-forming material to cure the exposed portions of the photosensitive layer; applying a liquid containing a reactive substance that reacts with the polymer to the image-forming material, whereby the reactive substance is exposed to light in the photosensitive layer. And permeating the polymer to the image forming layer by passing through the portion to react with the reactive substance and the polymer, thereby denaturing the polymer in the unexposed portion to insoluble in the eluate; An image forming method comprising the step of eluting an exposed portion of a forming layer and a photosensitive layer, thereby forming an image comprising a remaining image forming layer.

The image forming method of the above (1) includes the following (A)
It is preferable to carry out in the embodiment. (A) An image forming layer containing a water-insoluble polymer having an acidic group and a photosensitive layer containing a silver halide, a reducing agent, an ethylenically unsaturated polymerizable compound and a water-soluble polymer are sequentially provided on a support. Image-exposing the image-forming material; heating the image-forming material to cure the exposed portion of the photosensitive layer; applying an aqueous solution of a basic compound to the image-forming material, whereby the basic substance is removed from the photosensitive layer. By passing through the exposed portion to the image forming layer and reacting with the basic substance and the water-insoluble polymer having the acidic group, the acidic group of the polymer is converted into a salt state, and the unexposed portion of the polymer is dissolved in water. Forming a non-exposed portion of the image forming layer and the photosensitive layer with water, thereby forming an image comprising the remaining image forming layer. Law.

The image forming method of the above (2) includes the following (B)
Or it is preferable to carry out in the mode of (C). (B) An image forming layer containing a water-soluble polymer having an acidic group in a salt state and a photosensitive layer containing a silver halide, a reducing agent, an ethylenically unsaturated polymerizable compound and a water-soluble polymer are formed on a support. Image-exposing a sequentially provided image-forming material; heating the image-forming material to cure the exposed portions of the photosensitive layer; applying an aqueous solution of an acidic compound to the image-forming material, whereby the acidic compound is exposed to light. When the acidic substance and the water-soluble polymer having an acidic group in a salt state react with the water-soluble polymer having an acidic group in a salt state, the acidic group in the salt state of the polymer is passed through the unexposed portion of the layer to the image forming layer. Modifying the polymer in the unexposed area to be insoluble in water as an acid state; and elute the exposed area and the photosensitive layer of the image forming layer with water to form an image comprising the remaining image forming layer. Image forming method characterized by having a.

(C) An image-forming layer containing a water-soluble polymer having an acidic group in the form of a salt with a monovalent cation on a support, silver halide, a reducing agent, and an ethylenically unsaturated polymerizable compound. Image-exposing an image-forming material provided with a photosensitive layer containing a photosensitive layer and a water-soluble polymer in sequence; heating the image-forming material to cure exposed portions of the photosensitive layer; forming an aqueous solution of a salt of a polyvalent metal with an image Applied to the material, whereby the salt of the polyvalent metal penetrates through the unexposed portion of the photosensitive layer to the image forming layer, and is in a state of a salt of the salt of the polyvalent metal and the monovalent cation. Reacting with a water-soluble polymer having an acidic group to crosslink the polymer, thereby modifying the unexposed portion of the polymer to be insoluble in water; and elute the exposed portion and the photosensitive layer of the image forming layer with water. , The remaining image form Image forming method characterized by comprising the step of forming an image comprising a layer. Note that the support preferably has a hydrophilic surface. Further, the image composed of the remaining image forming layer is preferably hydrophobic or ink-receptive.

[0010]

According to the present invention, the present inventors have proposed a cured portion (exposed portion) of the photosensitive layer.
Attention was paid to the fact that there was a difference in the liquid permeability between the uncured portion and the uncured portion (unexposed portion), and the image was successfully formed using the difference. In the method of the present invention, it is sufficient that the photosensitive layer is cured to such an extent that liquid permeation can be inhibited, so that a clear image can be formed. Therefore, unlike the conventional image forming method in which the cured portion is used as an ink receiving area, an image can be formed even by thermal development with a considerably low energy amount (low temperature or short time). That is,
According to the present invention, the energy required for image formation can be greatly reduced. In the preferred embodiments (A), (B) and (C) of the present invention, the non-image portion of the image forming layer and the photosensitive layer can be eluted by washing with water. The aqueous solution of the reactive substance
The non-image portion of the image forming layer hardly elutes in the aqueous solution at the permeation stage because it rapidly permeates into the image forming layer. The polymer in the non-image area is eluted into water mainly during the washing step. In a conventional image forming method, a large amount of a polymer may be dissolved in a processing liquid (eg, an alkaline aqueous solution) to generate a large amount of harmful waste liquid. In the present invention, a waste liquid containing a harmful substance such as an alkali or an acid and a waste liquid (aqueous solution) of a substantially harmless polymer can be separated and disposed.

In general, in an image forming method, it is desirable that a method of forming a negative type image on a document and a method of forming a positive type image can be arbitrarily used as required. In the present invention, the method (1) for forming an image on an exposed portion and the method (2) for forming an image on an unexposed portion basically differ in the constitution of the image forming material, the properties of the components and the solvent (physical properties). Are identical. Therefore, a negative or positive image of substantially the same quality (having the same physical properties, mechanical strength and image quality) can be formed if necessary only by changing a part thereof. In a conventional image forming method, in addition to a method of forming an image on an exposed portion, a method of forming an image on an unexposed portion (described in JP-A-61-260241 described above) has been proposed. The method employs different chemical reactions as the principle of image formation. For this reason, in the prior art, it was difficult to form a homogeneous negative or positive image as in the present invention.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A particularly preferred embodiment of the image forming method of the present invention will be described with reference to FIGS. FIG. 1 is a schematic sectional view of an image forming material used in a preferred embodiment (A) of the image forming method of the present invention. As shown in FIG. 1, an image forming layer (12) containing a water-insoluble polymer having an acidic group, a silver halide, a reducing agent, an ethylenically unsaturated polymerizable compound, and a water-soluble solution are provided on a hydrophilic support (11). A photosensitive layer (13) containing a conductive polymer is sequentially provided. The photosensitive layer (13) is water-soluble and water-permeable. FIG. 2 is a schematic cross-sectional view showing a state of the image forming material after completion of the image exposure and heat development steps. FIG.
As shown in (2), the exposed portion (21) of the photosensitive layer is cured and becomes water-impermeable. On the other hand, the unexposed portion (2
2) has no substantial change and remains water permeable.
FIG. 3 is a schematic sectional view showing a step of applying an aqueous solution of a basic compound to an image forming material. As shown in FIG. 3, when the image forming material is immersed in an aqueous solution of a basic compound, the basic compound (31) penetrates through the unexposed portion (32) of the photosensitive layer to the image forming layer (33). . On the contrary,
The aqueous solution of the basic compound does not penetrate into the exposed portion (34) of the photosensitive layer.

FIG. 4 is a schematic sectional view showing the result of the reaction between the basic compound and the polymer of the image forming layer. As shown in FIG. 4, in the unexposed portion (41) of the image forming layer in which the basic compound has penetrated, the basic compound reacts with the polymer having an acidic group, and the acidic group of the polymer becomes a salt state. .
Thereby, the polymer is modified to be water-soluble. On the other hand, the polymer does not change in the exposed portion (42) of the image forming layer where the basic compound has not penetrated. FIG. 5 is a schematic cross-sectional view showing a water removing step. As shown in FIG. 5, when the image forming material is treated (washed) with water (51),
The unexposed portions and the photosensitive layer of the image forming layer are removed, and the hydrophilic support is exposed. FIG. 6 is a schematic cross-sectional view showing a state in which printing is being performed. As shown in FIG. 6, dampening water (61) adheres to the exposed hydrophilic support, and becomes ink repellent. The exposed portion of the image forming layer is ink-receptive, and the ink (62) adheres thereto. Note that the water washing step shown in FIG. 5 can be omitted, and the image forming material can be mounted on a printing machine to start printing. When printing is started, unexposed portions of the image forming layer and the photosensitive layer remain, but are removed by the action of dampening water or friction with the printing machine in a short time during the printing operation. After that, printing can be performed in the same manner as when the printer is mounted on a printing machine through a washing step.

FIG. 7 is a schematic sectional view of an image forming material used in another preferred embodiment (B) of the image forming method of the present invention. As shown in FIG. 7, on a hydrophilic support (71),
An image forming layer (72) containing a water-soluble polymer having an acidic group in a salt state, and a photosensitive layer (73) containing a silver halide, a reducing agent, an ethylenically unsaturated polymerizable compound and a water-soluble polymer are sequentially provided. Have been. Photosensitive layer (73)
Is water-soluble and water-permeable. FIG. 8 is a schematic cross-sectional view showing the state of the image forming material after the image exposure and heat development steps are completed. As shown in FIG. 8, the exposed portion (81) of the photosensitive layer cures and becomes water impermeable. On the contrary,
The unexposed portions (82) of the photosensitive layer remain substantially unchanged and remain water permeable. FIG. 9 is a schematic cross-sectional view showing a step of applying an aqueous solution of an acidic compound to an image forming material. As shown in FIG. 9, when the image forming material is immersed in an aqueous solution of an acidic compound, the acidic compound (91) permeates through the unexposed portion (92) of the photosensitive layer to the image forming layer (93).
On the other hand, the aqueous solution of the acidic compound does not penetrate into the exposed portion (94) of the photosensitive layer.

FIG. 10 is a schematic sectional view showing the result of the reaction between the acidic compound and the polymer of the image forming layer. As shown in FIG. 10, in the unexposed portion (101) of the image forming layer into which the acidic compound has penetrated, the acidic compound reacts with the polymer having the acidic group in a salt state, and the salt is converted into a free acidic group. State. Thereby, the polymer is modified to be insoluble in water. On the other hand, in the exposed portion (102) of the image forming layer where the acidic compound did not penetrate, the polymer did not change.
FIG. 11 is a schematic cross-sectional view showing a removing step using water.
As shown in FIG. 11, when the image forming material is treated (washed with water) with water (111), the exposed portions of the image forming layer are removed, and the hydrophilic support is exposed. FIG. 12 is a schematic cross-sectional view showing a state in which printing is being performed. As shown in FIG. 12, fountain solution (121) adheres to the exposed hydrophilic support,
It becomes ink repellent. The unexposed portions of the image forming layer are ink-receptive and adhere with the ink (122). Note that the water washing step shown in FIG. 11 may be omitted, and the image forming material may be mounted on a printing machine to start printing. When printing is started, the exposed portion of the image forming layer and the photosensitive layer remain, but are removed by the action of dampening water or friction with the printing machine in a short time during the printing operation. After that, printing can be performed in the same manner as when the printer is mounted on a printing machine through a washing step.

In still another preferred embodiment (C) of the image forming method of the present invention, a printing plate is manufactured and printed in steps similar to the steps shown in FIGS. That is, a material similar to the image forming material shown in FIG. 7 is used, and a salt of a polyvalent metal ion is used instead of the acidic compound shown in FIG. As a result, the polyvalent metal ion salt reacts with the polymer in the unexposed portion of the image forming layer where the salt has penetrated, whereby the polymer is crosslinked. Thereby, the polymer is modified to be insoluble in water. On the other hand, in the exposed portion, there is no change in the polymer. After that, when the treatment is performed in the same manner as the steps shown in FIGS. 10 to 12, the dampening water adheres to the hydrophilic region formed of the exposed portion on the surface of the support, and the ink becomes repellent. The hydrophobic areas are ink-receptive, to which ink adheres.

[Support] As the support, paper, synthetic paper,
Paper laminated with synthetic resin (eg, polyethylene, polypropylene, polystyrene), plastic film (eg, polyethylene terephthalate, polycarbonate, polyimide, nylon, cellulose triacetate), metal plate (eg, aluminum, aluminum alloy,
Zinc, iron, copper), and paper or plastic film on which these metals are laminated or deposited can be used. When the photosensitive material is used for producing a lithographic printing plate, preferred supports are an aluminum plate, a polyethylene terephthalate film, a polycarbonate film, paper and synthetic paper. Further, a composite sheet in which an aluminum sheet is laminated on a polyethylene terephthalate film is also preferable. Aluminum plates are particularly preferred.

The case where an aluminum plate is used as the support will be further described. The aluminum support is subjected to a surface treatment such as a surface roughening treatment (graining treatment) or a surface hydrophilic treatment as necessary. The surface roughening treatment may be performed by an electrochemical sanding method (for example, a method of sanding an aluminum plate by passing an electric current in a hydrochloric acid or nitric acid electrolyte) and / or a mechanical sanding method. (For example, a wire brush grain method in which the aluminum surface is scratched with a metal wire, a ball grain method in which the aluminum surface is sanded with a polishing ball and an abrasive, a brush grain in which the surface is sanded with a nylon brush and an abrasive) Method).

Next, the grained aluminum plate is chemically etched with an acid or an alkali. An industrially advantageous method is etching using an alkali. Examples of the alkaline agent include sodium carbonate, sodium aluminate, sodium metasilicate, sodium phosphate, sodium hydroxide, potassium hydroxide and lithium hydroxide. The concentration of the alkaline solution is preferably in the range of 1 to 50% by weight. The temperature of the alkali treatment is preferably in the range of 20 to 100 ° C. Further, it is preferable to adjust the processing conditions so that the amount of aluminum dissolved is 5 to 20 g / m ² . Usually, after the alkali etching, the aluminum plate is washed with an acid to remove dirt (smut) remaining on the surface.
Preferred acids are nitric, sulfuric, phosphoric, chromic, hydrofluoric and borofluoric acids. The smut removal treatment after the electrochemical surface roughening treatment is performed at 50 to 90 ° C. for 15 minutes.
It can be carried out by a known method such as a method of contacting sulfuric acid with a concentration of about 65% by weight.

The aluminum plate subjected to the surface roughening treatment as described above can be subjected to an anodic oxidation treatment or a chemical conversion treatment, if necessary. The anodic oxidation treatment can be performed by a known method. Specifically, in an acid solution,
An anodic oxide film is formed on the aluminum surface by passing a direct current or an alternating current through the aluminum plate. Examples of acids include sulfuric acid, phosphoric acid, chromic acid, oxalic acid, sulfamic acid and benzenesulfonic acid. Anodizing conditions vary depending on the electrolyte used. Generally, the concentration of the electrolyte is 1 to 80% by weight, the temperature of the electrolyte is 5 to 70 ° C., the current density is 0.5 to 60 amps / dm ² , the voltage is 1 to 100 V, and the electrolysis time is 10 to 10%. It is preferably within a range from 100 to 100 seconds. Particularly preferred anodic oxidation methods are a method of performing anodization at a high current density in sulfuric acid and a method of performing anodization using phosphoric acid as an electrolytic bath. After the anodizing treatment, the aluminum plate may be subjected to an alkali metal silicate treatment (for example, a treatment of immersing the aluminum plate in an aqueous solution of sodium silicate). In order to improve the adhesion between the aluminum support and the image-forming layer and the printing characteristics, an undercoat layer may be provided on the support surface.

[Undercoat layer] The undercoat layer is provided as a hydrophilic layer on a support whose surface is not sufficiently hydrophilic (eg, a polymer film) in addition to the aluminum support described above. As a component constituting the undercoat layer, a polymer (eg,
Gelatin, casein, polyvinyl alcohol, ethyl cellulose, phenolic resin, styrene-maleic anhydride resin, polyacrylic acid); amines (eg, monoethanolamine, diethanolamine, triethanolamine,
Tripropanolamine) and their hydrochlorides, oxalates or phosphates; monoaminomonocarboxylic acids (eg, aminoacetic acid, alanine); oxyamino acids (eg,
Serine, threonine, dihydroxyethylglycine);
Sulfur-containing amino acids (eg, cysteine, cystine); monoaminodicarboxylic acids (eg, aspartic acid, glutamic acid); diaminomonocarboxylic acids (eg, lysine); amino acids having an aromatic nucleus (eg, p-hydroxyphenylglycine, phenylalanine) Aliphatic aminosulfonic acid (eg, sulfamic acid, cyclohexylsulfamic acid); and (poly) aminopolyacetic acid (eg, ethylenediaminetetraacetic acid, nitrilotriacetic acid, iminodiacetic acid, hydroxyethyliminodiacetic acid, hydroxyethylethylenediamine) Acetic acid, ethylenediaminediacetic acid, cycloethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, glycol etherdiaminetetraacetic acid). A compound in which some or all of the acid groups of the above compounds have become salts (eg, sodium salt, potassium salt, ammonium salt) can also be used. The above components can be used in combination of two or more. When a polymer film is used as the support, hydrophilic fine particles (eg, silica powder) are preferably added to the hydrophilic undercoat layer instead of the graining treatment of the aluminum support.

[Combination of Polymer, Reactive Substance and Eluate] The combination of polymer, reactive substance and eluate in the image forming layer used in the present invention should satisfy the following relationship (1) or (2). Good. (1) When a reactive substance acts on a polymer that is insoluble in an eluate, the polymer becomes soluble in the eluate. (2) When a reactive substance acts on a polymer that is soluble in the eluate, the polymer becomes insoluble in the eluate. In a general polymer chemical reaction, the solubility in a specific liquid often changes. Accordingly, chemical reactions of various types of polymers can be applied to the present invention. The solubility of a polymer in a particular liquid is determined by the molecular weight and chemistry of the polymer. As the molecular weight of the polymer increases, the solubility decreases, and as the molecular weight of the polymer decreases, the solubility increases. Also, as the affinity of the polymer for the liquid increases, the solubility increases, and as the affinity of the polymer for the liquid decreases, the solubility decreases. Therefore, the reactive substance may change the molecular weight of the polymer or the affinity for the liquid.

It is preferred that the side chains (or functional groups) react more than the main chain of the polymer. In order to change the molecular weight of the polymer by the reaction of the main chain, a polymerization reaction or a decomposition reaction of the polymer is required. Side chain (or functional group)
In this case, the molecular weight of the polymer can be significantly changed by a relatively simple crosslinking reaction (or a reaction for cleaving the crosslinking). Also, it is difficult to change the chemical properties of the main chain of the polymer, but the chemical properties of the functional groups can be easily changed. The reaction of the polymer includes an acid-base reaction (details will be described later), an oxidation-reduction reaction (for example, formation or cleavage of a cross-link between polymers by an -S-S- bond), and a hydrolysis reaction (for example, formation of an ester bond in a side chain) Formation of a hydroxyl group or a carboxylic acid group by decomposition), radical crosslinking reaction (for example, attaching a precursor of a radical and crosslinking the polymer by heating or light irradiation), complex formation reaction or polymerization reaction (for example, to a hydrophilic side chain). (Graft polymerization of hydrophobic substances). The reactive substance used in the present invention includes a substance that functions as a catalyst (or an enzyme) in the reaction, in addition to a substance directly involved in the reaction of the polymer.

The reaction of the polymer may be caused to proceed by a treatment such as heating or exposure.
There is a possibility that the effect of the present invention, which can be implemented with simple processing, may be impaired. Therefore, the reaction preferably proceeds at room temperature without requiring external energy. The liquid used as the eluate is neutral water (or aqueous solvent),
Any of an alkaline aqueous solution, an acidic aqueous solution and an organic solvent may be used. However, neutral water (or aqueous solvent)
Is most preferable because it has no problem of waste liquid treatment. Therefore, when the chemical properties of the polymer are changed by the reaction, it is preferable to change the hydrophilic group of the polymer to hydrophobic (reduced solubility in water) or to change the hydrophobic group to hydrophilic. When a polymer having an acidic group or a salt thereof is used, the solubility of the polymer in water can be easily changed by an acid-base reaction. Hereinafter, the polymer having an acidic group will be described in more detail.

[Polymer having acidic group] The polymer having an acidic group is a polymer having an acidic group (eg, a carboxyl group, an acid anhydride group, a sulfonic acid group, a sulfate group, a phosphate group) in a molecule. is there. The molecular weight is 50
It is preferably in the range of 00 to 500,000. The polymer having an acidic group can be synthesized by addition polymerization of a monomer having an ethylenically unsaturated bond. That is, it can be synthesized by homopolymerizing a monomer having an acidic group or copolymerizing with a monomer having no acidic group.
For example, a homopolymer of a vinyl monomer having an acidic group (eg, acrylic acid, methacrylic acid, maleic anhydride, styrenesulfonic acid), or a vinyl monomer having no acidic group with these vinyl monomers (eg, acrylates, Methacrylates, acrylamides,
Methacrylamides, styrenes, vinyl ethers,
(Vinyl esters, ethylene).

Polyester or polyamide can be used as the polymer having an acidic group. Ordinary polyesters or polyamides are synthesized by polycondensation of a divalent or higher valent organic acid with an equimolar amount of a divalent or higher valent alcohol or amine compound. In the synthesis, by using a trivalent or higher acid as a part of the organic acid, a free acidic group can be introduced into the polymer. The polymer having an acidic group can also be synthesized by introducing an acidic group into a natural or synthetic polymer (eg, carboxymethyl cellulose). As the polymer having an acidic group, a polymer which is insoluble in water when the acidic group is in a free acid state (state in which no salt is formed) is used. The properties of such polymers are influenced by the type of acidic groups, the content of acidic groups in the polymer and the degree of hydrophobicity of the polymer backbone. Generally, if the density of the acidic group in 1 g of the polymer is in the range of 5 × 10 ^{−5 to} 3 × 10 ⁻³ mol, the above property is satisfied. In the image forming material of the above-mentioned embodiment (A), a polymer having such an acidic group is used.

In the image-forming materials of the above-mentioned embodiments (B) and (C), at least a part of the acidic groups of the polymer is neutralized to form a salt, and as a result, the polymer becomes water-soluble. The neutralization ratio (the ratio of the acidic groups to salts) required to make the polymer having an acidic group water-soluble depends on the content of the acidic group in the polymer and the nature of the polymer skeleton. It is preferable to select the neutralization rate after confirming the properties. The neutralization ratio is generally preferably in the range of 50 to 100%, and more preferably in the range of 70 to 100%. Incidentally, the acidic group of the polymer used in the image forming material of the embodiment (A) may be a salt as long as the polymer does not become substantially water-soluble.

In order to convert the acidic group of the polymer into a salt, the polymer may be synthesized using a monomer in which the acidic group of the monomer having an acidic group is converted into a salt, or a polymer having an acidic group which is not salted may be synthesized. After synthesizing, the acidic group may be neutralized with a basic substance to form a salt. The cation for converting the acidic group into a salt is preferably a monovalent metal ion or ammonium ion. In the image forming material of the embodiment (C), it is necessary to form a salt with a monovalent cation. Also, in the embodiments (A) and (B), it is preferable to use a monovalent cation (or a monovalent basic compound). Specific examples of the basic compound for neutralizing the acidic group to a salt, lithium hydroxide, sodium hydroxide, potassium hydroxide, sodium methoxide, potassium methoxide,
Sodium carbonate, potassium carbonate, sodium acetate, potassium acetate, sodium silicate, potassium silicate, sodium metasilicate, potassium metasilicate, sodium phosphate, potassium phosphate, disodium hydrogen phosphate, dipotassium hydrogen phosphate, hydroxide Ammonium and organic amines can be mentioned.

The polymer having an acidic group (or a salt thereof) is preferably non-crosslinkable, that is, a polymer which does not crosslink or cure by reacting with a free radical. When the polymer of the image forming layer is crosslinkable and is cured by radicals generated in the photosensitive layer, the polymerized image formed on the photosensitive layer in the exposed area and the polymer of the image forming layer are strongly bonded, and the polymerized image is removed by washing with water. It becomes difficult. In the embodiment (A), when the polymerized image of the photosensitive layer remains on the image portion of the image forming layer, it contains a large amount of the hydrophilic polymer, and thus the printing ink is hardly deposited. In the modes (B) and (C), the polymer of the image forming layer in the exposed area is also cured to leave a film on the support, and the non-image area lacks the repellency of the printing ink, thereby causing background fouling.

[Image Forming Layer] The image forming layer is a layer containing the aforementioned polymer as a main component. A colorant can be added to the image forming layer for the purpose of visualizing an image.
Known pigments or dyes can be used as the colorant. A surfactant can be added to the image forming layer. As the surfactant, a known nonionic activator, anionic activator, cationic activator, amphoteric activator or fluorine-containing activator can be used. The image forming layer is
As long as the solubility is not impaired, a polymer having no acidic group can be included in addition to the polymer having an acidic group (or a salt thereof). Examples of polymers having no acidic group include vinyl polymers (eg, polyacrylates, polymethacrylates), synthetic polymers such as polyesters and polyamides, and natural or semi-synthetic polymers such as celluloses. be able to.

When the obtained image is used as a lithographic printing plate, the surface of the image portion must be lipophilic to some extent because the image portion needs to receive (flood) the printing ink. When the lipophilicity of the polymer having an acidic group is insufficient, as long as the solubility is not impaired,
An oily substance can be added to the image forming layer for the purpose of improving the inking property of the image area. Examples of the oily substance include polymer plasticizers (eg, phthalates, phosphates), higher fatty acid esters (eg, linseed oil, poppy oil), paraffins, and waxes. The thickness of the image forming layer is preferably in the range of 0.3 to 30 μm, more preferably in the range of 0.5 to 5 μm.

[Photosensitive layer] The photosensitive layer contains a silver halide, a reducing agent and an ethylenically unsaturated polymerizable compound. The photosensitive layer preferably further contains a water-soluble polymer as a binder. The thickness of the photosensitive layer is preferably in the range of 0.1 to 20 μm, and more preferably in the range of 0.3 to 5 μm.

[Silver halide] As silver halide,
Any grains of silver chloride, silver bromide, silver iodide, or silver chlorobromide, silver chloroiodide, silver iodobromide, silver chloroiodobromide can be used. The shape of the silver halide grains is preferably cubic or tetradecahedral, but is not limited to those having a regular crystal form, and may be those having an irregular crystal form or a complex form thereof. Anomalous crystal forms include potato, spherical, plate and plate crystal forms. In the case of tabular grains, the grain size is generally at least five times the grain thickness. There is no particular limitation on the grain size of the silver halide. Fine particles of 0.01 μm or less can also be used. On the other hand, large particles of about 10 μm can be used. With respect to grain size distribution, monodisperse grains are preferred over polydisperse emulsions. For monodisperse emulsions, see US Pat.
Nos. 628 and 3655394 and British Patent 1413.
No. 748 is described in each specification.

The crystal structure of the silver halide grains may be uniform or may have a different halogen composition between the inside and the outside. It may have a layered structure. Further, silver halides having different compositions may be joined by epitaxial joining. Further, it may be bonded to a compound other than silver halide. Examples of compounds other than silver halide include silver rhodan and lead oxide. The silver halide grains may contain salts of other elements. Examples of other elements include copper, thallium, lead, bismuth, cadmium, zinc, chalcogens (eg, sulfur, selenium, tellurium), gold and Group VIII noble metals (eg, rhodium, iridium, iron, platinum, palladium) Can be mentioned. Salts of these elements can be added during or after the formation of silver halide grains and included in the grains. Specific methods are described in U.S. Patent Nos. 1195432, 1951933, 2448860 and 26281.
Nos. 67, 2950972, 3488709, 3737313, 37372031, 42699
No. 27, and Research Disclosure (RD), Vol. 13452 (June 1975).

By adding an aqueous solution of an iridium compound to the emulsion during the preparation of the silver halide emulsion, iridium ions can be introduced into the silver halide grains. Examples of the water-soluble iridium compound include hexachloroiridium (III) and hexachloroiridium (IV). Similarly, rhodium ions may be introduced into silver halide grains by adding an aqueous solution of a rhodium compound to the emulsion. Examples of the water-soluble rhodium compound include rhodium ammonium chloride, rhodium trichloride and rhodium chloride. An iridium compound or a rhodium compound may be used by dissolving it in an aqueous solution of a halide for forming silver halide grains. Further, the aqueous solution of the iridium compound or the rhodium compound may be added before the particles are formed, or may be added during the formation of the particles. Further, it may be added during the period from grain formation to chemical sensitization treatment. It is particularly preferred to add while the particles are being formed. The iridium ion or the rhodium ion is preferably used in an amount of 10 ^{-8 to} 10 ^-3 mol, more preferably 10 ^{-7 to} 10 ^-5 mol, per 1 mol of silver halide.

Two or more kinds of silver halide grains having different halogen compositions, crystal habits and grain sizes can be used in combination. Silver halide is preferably used as an emulsion. Silver halide emulsions are described in Research Disclosure (RD) Magazine, No. 17643 (December 1978
Mon., pp. 22-23, "I. Emulsion Production (Emulsion prepa
ration and types) "and No. 18716 (19
Nov. 1979), p. 648. The silver halide emulsion is usually subjected to chemical sensitization after physical ripening. It is preferable to use silver halide grains having a relatively low fog value. Additives used in such a process are described in Research Disclosure Magazine, No. No. 17643 and the same No. 18716. Regarding chemical sensitizers, 17643 (23
Page) and No. 18716 (page 648, right column). Known additives other than those described above are also described in the above two Research Disclosures. For example, as for the sensitivity enhancer, 1871
No. 6 (right column on page 648), No. 6 No. 17643 (pages 24 to 25) and no. 1
8716 (from page 649, right column).

The silver halide emulsion is usually used after spectral sensitization. As the sensitizing dye used in the light-sensitive material, a silver halide sensitizing dye known in the photographic art can be used. Examples of sensitizing dyes include cyanine dyes,
Examples include merocyanine dyes, complex merocyanine dyes, holopolar cyanine dyes, hemicyanine dyes, styryl dyes, and hemioxonol dyes. Spectral sensitizing dyes are used to adjust the spectral sensitivity of photosensitive materials to different light source wavelengths such as various lasers (eg, semiconductor laser, helium neon laser, argon ion laser, helium cadmium laser, YAG laser) and light emitting diodes. Can also be used. For example, applying a plurality of spectral sensitizing dyes having different spectral wavelengths to silver halide in the same or different photosensitive layers to enable writing on the same photosensitive material using light sources having different wavelengths. Can also. In addition to the sensitizing dye, a dye which does not itself have a spectral sensitizing effect or a compound which does not substantially absorb visible light and exhibits supersensitization (supersensitizer) can be added to the emulsion. Good. Spectral sensitizing dyes are described in Research Disclosure Magazine, No. 17643 (197
December, 8), pp. 23-24, for supersensitizers
No. 18716 (November 1979), p. 649,
Each is listed. The coating amount of silver halide is preferably 0.01 to 5 g / m ² in terms of silver,
More preferably, it is 0.03 to 1 g / m ² ,
Most preferably, it is 0.05 to 0.3 g / m ² .

[Organic Metal Salt] The photosensitive layer may contain an organic metal salt together with silver halide. Organic silver salts are particularly preferred as the organic metal salts. Examples of the organic compound used to form the organic silver salt include triazoles, tetrazoles, imidazoles, indazoles, thiazoles, thiadiazoles, azaindenes, and aliphatic, aromatic, or aromatic compounds having a mercapto group as a substituent. Heterocyclic compounds can be mentioned. Further, silver salts of carboxylic acids and silver acetylene can also be used as organic silver salts. Two or more organic silver salts may be used in combination. The organic silver salt is used in an amount of 10 ^{-5 to} 10 mol, preferably 10 ^{-4 to} 1 mol, per 1 mol of silver halide.

[Reducing Agent] The reducing agent has a function of reducing silver halide or a function of promoting polymerization of a polymerizable compound (or crosslinking of a crosslinkable polymer). As the reducing agent, hydrazines, hydroquinones, catechols,
p-aminophenols, p-phenylenediamines,
3-pyrazolidones, 3-aminopyrazoles, 4-amino-5-pyrazolones, 5-aminouracils, 4,
5-dihydroxy-6-aminopyrimidines, reductones, aminoreductones, o- or p-sulfonamidophenols, o- or p-sulfonamidonaphthols, o- or p-acylaminophenols,
2-Sulfonamide indanones, 4-sulfonamido-5-pyrazolones, 3-sulfonamidoindoles, sulfonamidopyrazolobenzimidazoles, sulfonamidopyrazolotriazoles and α-sulfonamidoketones are used.

The reducing agent is described in JP-A-61-183640,
Nos. 61-188535, 61-228441, 62-70836, 62-86354 and 62-
No. 86355, No. 62-206540, No. 62-26
No. 4041, No. 62-109437, No. 63-254
442, JP-A-1-267536 and 2-1417
No. 56, No. 2-141775, No. 2-207254
And JP-A-2-262662 and JP-A-2-269352 (including those described as a developing agent or a hydrazine derivative). As for the reducing agent,
"The Theory of the Photographic Proces" by T. James
s "Fourth Edition, pp. 291-334 (1977), Research Disclosure, Vol. 170, No. 17029.
No. 9-15, (June 1978), and the same magazine, Vo
l.176, No.17643, pp.22-31, (1978
December). Further, Japanese Patent Application Laid-Open No. 62-210
As in the light-sensitive material described in Japanese Patent No. 446, a reducing agent precursor that releases the reducing agent under heating conditions or in contact with a base may be used instead of the reducing agent.

The basic reducing agent which forms a salt with an acid can be used in the form of a salt with a suitable acid. Two or more reducing agents may be used in combination. The interaction of two or more reducing agents is, first, to promote the reduction of silver halide (or organic silver salt) by so-called superadditivity, and second, to promote silver halide (or organic silver salt). It is conceivable that the oxidized form of the first reducing agent generated by the reduction of the compound causes a polymerization of the polymerizable compound through an oxidation-reduction reaction with another coexisting reducing agent. The reducing agent is preferably used in an amount of 0.1 to 10 mol per mol of silver halide.
It is more preferable to use 0.25 to 2.5 mol.

[Ethylenically unsaturated polymerizable compound] The polymerizable compound is a compound (monomer or oligomer) having an ethylenically unsaturated group capable of undergoing addition polymerization by free radicals. The ethylenically unsaturated polymerizable compound is described in JP-A-5-249667. Examples of ethylenically unsaturated polymerizable compounds include acrylic acid and salts thereof, acrylic esters, acrylamides, methacrylic acid and salts thereof, methacrylic esters, methacrylamides, maleic anhydride, maleic esters, Examples include itaconic esters, styrenes, vinyl ethers, vinyl esters, N-vinyl heterocycles, allyl ethers and allyl esters. Acrylic esters or methacrylic esters are particularly preferred. Specific examples of (meth) acrylates include pentaerythritol tetra (meth) acrylate, trimethylolpropane tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, polyester (meth) acrylate and polyurethane (meth) acrylate Can be mentioned. Two or more ethylenically unsaturated polymerizable compounds may be used in combination. When the ethylenically unsaturated polymerizable compound is hydrophobic, it is preferable that the compound is emulsified and dispersed in an aqueous solution of a water-soluble polymer described later and added to the photosensitive layer. The water-soluble ethylenically unsaturated polymerizable compound can be uniformly dissolved in an aqueous solution of a water-soluble polymer. The amount of the polymerizable compound is preferably in the range of 0.1 to 5 g, more preferably 0.3 to 2 g, per gram of the water-soluble polymer.

[Anti-fogging agent, silver development accelerator, stabilizer]
To improve the photographic properties, the photosensitive layer can contain an antifoggant, a silver development accelerator or a stabilizer. Examples thereof include a mercapto compound (JP-A-59-1116).
No. 36), azoles and azaindenes (Research Disclosure Magazine No. 17643, 24-
Page 25 (1978)), carboxylic acids and phosphoric acids containing nitrogen (described in JP-A-59-168442), cyclic amides (described in JP-A-61-151841), and thioethers (described in JP-A-62-14841). No. 151842), polyethylene glycol derivatives (Japanese Unexamined Patent Publication No. Sho 62-62).
No. 151843), thiols (JP-A-62-1)
No. 51844), acetylene compounds (Japanese Unexamined Patent Publication No.
2-87957) and sulfonamide (described in JP-A-62-178232). As the silver development accelerator or the antifoggant, an aromatic ring (carbon ring or heterocyclic) mercapto compound (described in JP-A-6-313967) is particularly preferred. Aromatic heterocyclic mercapto compounds, particularly mercaptotriazole derivatives, are more preferred. The mercapto compound may be added to the light-sensitive material as a mercapto silver compound (silver salt). The amount of these compounds used is in the range of 10 ^-7 mol to 1 mol per mol of silver halide.

[Thermal Development Accelerator] In order to accelerate the thermal development and perform the thermal development at a lower temperature or in a shorter time, a thermal development accelerator can be added to the photosensitive layer or the overcoat layer described later. As the thermal development accelerator, a compound having a plasticizing effect at room temperature or upon heating with respect to a binder used in any layer of the photosensitive material, or a compound having no plasticizing effect but capable of melting in the layer by heating is used. Can be used. It is considered that the thermal development accelerator promotes thermal development by promoting the diffusion of the reactant in the photosensitive material or by promoting the reaction itself.
Examples of the compound having a plasticizing effect include “Plastic Additives, 2nd Edition”, “Plastics Additives, 2nd Edition”, Taiseisha, P21-63;
ser Publishers) Polymer plasticizers described in Chapter 5, pages 251-296 can be used. Preferred thermal development accelerators include polyethers (eg, polyethylene glycol, polypropylene glycol), polyhydric alcohols (eg, glycerin, hexanediol), sugars (eg, sorbitol), formate esters, ureas (eg, urea, diethyl) Urea, ethylene urea), amides (eg, acetamide, propionamide, malonamide), sulfamides, sulfonamides, urea resins and phenol resins. Two or more thermal development accelerators can be used in combination. Further, it may be added in two or more layers. The amount of the thermal development accelerator added is 0.0
5 to 2 g / m ² , preferably 0.1 to 1 g / m ^2.
g / m ² is more preferable.

[Development Stopping Agent] Various development stopping agents can be used for the purpose of always obtaining a constant image with respect to the processing temperature and the processing time during thermal development. A development terminator is a compound that immediately neutralizes a base or reacts with a base to reduce the base concentration in a layer and stop development after proper development, or a compound that interacts with silver and a silver salt to suppress development. is there.
Specifically, an acid precursor that releases an acid upon heating,
An electrophilic compound that undergoes a substitution reaction with a coexisting base upon heating, or a nitrogen-containing heterocyclic compound, a mercapto compound, and a precursor thereof can be used. The thermal development terminator is described in JP-A-62-253159 and JP-A-2-2-159.
Nos. 42447 and 2-262661.

[Base and Base Precursor] It is preferable to add a base or a base precursor to the photosensitive layer or the overcoat layer described later. As the base, various inorganic and organic bases are used. As the base precursor, those precursors (decarboxylation type, pyrolysis type,
Reaction type, complex salt forming type or dissociation type) can be used. From the viewpoint of storage stability of the photosensitive material, a base precursor is more preferable than a base. Examples of the decarboxylation type base precursor include salts of organic acids and bases which can be decarboxylated by heating (JP-A-63-316760, JP-A-64-68746, and JP-A-68-74646).
Nos. 9-180537 and 61-313431). Examples of the pyrolytic base precursor include urea compounds (JP-A-63-9663).
159). Examples of the reactive base precursor include transition metal acetylide (described in JP-A-63-25208). Examples of complex salt-forming base precursors include basic metal compounds that are poorly soluble in water (described in JP-A-1-28282). Examples of dissociative base precursors include alkali metal salts of organic acids (eg, sodium acetate, sodium salts of polymers having acidic groups). The base precursor is 50-200
Preferably, the base is formed at a temperature of 80 ° C, more preferably at 80 to 160 ° C. The amount of the base or base precursor to be added is per mole of silver halide.
It is preferably in the range of 0.4 to 20 moles,
More preferably, it is in the range of 1 to 10 mol.

[Polymerization Inhibitor] In order to prevent polymerization of the polymerizable compound during storage of the photosensitive material, the photosensitive layer may contain a polymerization inhibitor. Conventionally known polymerization inhibitors (eg,
Nitrosamines, ureas, thioureas, thioamides, phenols, amines) can be used.

[Water-soluble polymer] Examples of the water-soluble polymer include polyvinyl alcohol (including modified polyvinyl alcohol), polyvinyl pyrrolidone, poly (meth) acrylate (eg, sodium salt), poly (meth) acrylamide, and polystyrene sulfone. Acid salts (eg, sodium salt), cellulose ethers (methyl cellulose, hydroxypropyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose sodium salt), gelatin, and gum arabic can be exemplified. Polyvinyl alcohol is particularly preferred. Polyvinyl alcohol has a saponification degree of 70 in order to reduce oxygen permeability.
% Or more, more preferably 80% or more, most preferably 90% or more. However, as described later, when an overcoat layer containing polyvinyl alcohol having a saponification degree of 90% or more is provided, the water-soluble polymer of the photosensitive layer may be an oxygen-permeable polymer. The molecular weight of the water-soluble polymer is 3000 to 500
000 is preferred. The coating amount of the water-soluble polymer is preferably in the range of 0.1 to 10 g / m ² , and more preferably in the range of 0.2 to 3 g / m ² .

[Overcoat layer] An overcoat layer can be provided on the photosensitive layer. The overcoat layer has a function of protecting the photosensitive layer and preventing oxygen in the air from penetrating into the photosensitive layer during image formation and inhibiting polymerization of the polymerizable compound. The overcoat layer contains a water-soluble polymer. As the water-soluble polymer, the polymer used for the photosensitive layer described above is used. Polymers with low oxygen permeability are preferred. Polyvinyl alcohol having a saponification degree of 90% or more is particularly preferably used. The thickness of the overcoat layer is preferably in the range of 0.3 to 20 μm, more preferably in the range of 0.5 to 7 μm.

[Colorant] A colorant can be added to a printing original plate for the purpose of preventing halation and irradiation, and adjusting the coloring or sensitivity (absolute sensitivity and spectral sensitivity) of an image. As the colorant, known pigments and dyes can be used as long as they do not significantly impair the photosensitivity and polymerizability of the photosensitive layer. When a colorant is used for the purpose of preventing halation or irradiation, the colorant is preferably added to the image forming layer or the photosensitive layer. When used for the purpose of coloring an image, a colorant is preferably added to the image forming layer. It is preferable that the coloring agent for preventing halation and irradiation absorbs light in the photosensitive wavelength range of the optical sensor. When used for the purpose of adjusting the sensitivity, the colorant is preferably added to the overcoat layer or the photosensitive layer. The coloring agent can be added to the intermediate layer described below. As a coloring agent, see
Pigment, dye or colloidal silver described in JP-A-249669, Color Index Handbook and Dye Handbook (edited by The Society of Synthetic Organic Chemistry, 1970) can be used. Dyes for preventing irradiation which have little influence on the sensitivity of silver halide are disclosed in JP-B-41-20389 and JP-B-43-3.
Nos. 504, 43-13168 and JP-A-2-39.
No. 042, and US Pat. No. 3697037;
No. 3,423,207, British Patent Nos. 1,030,392 and 1,100,546. The amount of the colorant added is preferably in the range of 0.01 to 2 g / m ² ,
The range is more preferably from 0.05 to 1 g / m ² .

[Surfactant] A known surfactant may be added to any of the layers. Any of a nonionic activator, an anionic activator, a cationic activator and a fluorine activator can be used. For the surfactant, see JP-A-2-195356.
There is a description in the publication. Sorbitans, polyoxyethylenes and fluorinated surfactants are particularly preferred.

[Matting Agent] A matting agent is added to the back layer or overcoat layer of the image forming material for the purpose of reducing the tackiness of the front or back surface of the image forming material and preventing adhesion when the image forming material is overlaid. Can be added. As the matting agent, inorganic or organic solid particles that can be dispersed in a hydrophilic polymer are used. Examples of matting agent materials include oxides (eg, silicon dioxide), alkaline earth metal salts, and natural polymers (eg, starch, cellulose)
And synthetic polymers. The particle size of the matting agent is preferably in the range of 0.5 to 50 μm. The coating amount of the matting agent is preferably in the range of 0.1 to 1 g / m ² .

[Intermediate layer] An intermediate layer can be provided between the respective layers. The intermediate layer functions as an adhesive layer between layers, an antihalation layer containing a coloring agent, or an optical filter layer. The intermediate layer preferably contains the above water-soluble polymer. The thickness of the intermediate layer is preferably 5 μm or less.

[Image Exposure] Image exposure is performed using light having a wavelength corresponding to the spectral sensitivity of silver halide. The wavelength is generally visible light, near ultraviolet light, or near infrared light, but X-rays or electron beams may be used. Examples of the light source include a tungsten lamp, a halogen lamp, a xenon lamp, a xenon flash lamp, a mercury lamp, various lasers (eg, a semiconductor laser, a helium neon laser, a helium cadmium laser, a YAG laser, an argon laser), a light emitting diode. And a cathode ray tube. The exposure amount is preferably in the range of 0.001 to 1000 μJ / cm ² , and 0.01 to 100 μJ / cm ^2.
More preferably, it is within the range. When the support is transparent, image exposure can also be performed through the support from the back side of the support.

[Thermal Development] The thermal development can be performed by a method of bringing the image forming material into close contact with a heated object (eg, a metal plate or a metal roller), a method of immersing the material in a heated liquid, a method of irradiating infrared rays, or the like. it can. The surface of the image forming material may be opened to the air and heated from the support side, or the surface may be brought into close contact with a heated object and heated in a state where the air is shut off. If you open the surface into the air and heat it,
Since oxygen in the air may penetrate into the image forming material and inhibit the polymerization reaction, it is preferable to use the above-described polymer having a low oxygen transmittance for the photosensitive layer or the overcoat layer. The heating temperature is in the range of 60 to 200 ° C, preferably 100 to 160 ° C. Heating time is 1 to 1
It is in the range of 80 seconds, preferably 5 to 60 seconds.

[Application of Reactive Substance Solution] After thermal development, a reactive substance solution is applied to the image forming material. Specifically, the method of immersing the image forming material in a solution of a reactive substance is the simplest and preferable. The immersion time is preferably in the range of 1 to 60 seconds, more preferably in the range of 5 to 30 seconds. Instead of immersing the image forming material in the solution, the solution may be spread on the image forming material.

In the image forming method of the embodiment (A),
A solution of a basic compound is used. The basic compound is preferably monovalent. As specific examples of the basic compound,
Lithium hydroxide, sodium hydroxide, potassium hydroxide,
Sodium methoxide, potassium methoxide, sodium carbonate, potassium carbonate, sodium acetate, potassium acetate, sodium silicate, potassium silicate, sodium metasilicate, potassium metasilicate, sodium phosphate,
Potassium phosphate, disodium hydrogen phosphate, dipotassium hydrogen phosphate, ammonium hydroxide and organic amines can be mentioned. The concentration of the basic compound in the solution is
It is preferably in the range of 0.03 to 5 mol / l, more preferably in the range of 0.1 to 2 mol / l.

In the image forming method of the embodiment (B),
A solution of the acidic compound is used. As the acidic compound, any of inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid and phosphoric acid and organic acids such as acetic acid, oxalic acid, citric acid and benzenesulfonic acid can be used. The concentration of the acidic compound in the solution is preferably in the range of 0.03 to 5 mol / l, and more preferably in the range of 0.1 to 2 mol / l.

In the image forming method of the embodiment (C),
A solution of a polyvalent metal ion salt is used. Examples of polyvalent metal ion salts include magnesium, calcium, strontium, barium, aluminum, chromium, manganese,
Examples thereof include salts (including complex salts) of divalent or higher cations of metals such as iron, cobalt, nickel, copper, zinc, and tin (preferably alkaline earth metals). Although any counter anion may be used, it is preferable to select an anion having good solubility of the metal salt. Specific examples of the polyvalent metal ion salt include magnesium chloride, magnesium sulfate, magnesium nitrate, magnesium acetate, calcium chloride, calcium sulfate, calcium nitrate, and calcium acetate. The concentration of the polyvalent metal ion salt in the solution is 0.0
It is preferably in the range of 3 to 5 mol / l,
More preferably, it is in the range of 0.1 to 2 mol / l.

Even if the acidic group of the polymer having an acidic group is in the form of a salt, the cation is replaced with the above-mentioned polyvalent metal ion, and the polymer can be crosslinked to be modified to be water-insoluble. The solvent used in the above solution is the same as that of the embodiment (A)
In any of the cases (C) to (C), it is preferable to use water as a main component. A surfactant may be added to the solution of the reactive substance. The solution of the reactive substance may be colored with a coloring agent.

[Elution Treatment] The elution treatment is carried out using a polymer in the non-image portion of the image forming layer and a liquid capable of eluting the photosensitive layer. In preferred embodiments (A) to (C),
The elution treatment (water washing treatment) can be performed using water. The temperature of the water used in the water washing step is preferably 10 to 100 ° C, more preferably 20 to 70 ° C. The washing step is preferably performed by rubbing the image forming material with a brush or sponge in water. The time for immersing the image forming material in water is preferably from 10 to 120 seconds, and more preferably from 30 to 60 seconds. To the water used in the water washing step, a surfactant or an organic solvent miscible with water (however, the amount used may be 30% by weight or less of the total amount with water) may be added.

[Post-heating treatment] The mechanical strength of the image is increased,
In particular, when the image is used as a printing plate, the obtained image can be heated after the dissolution treatment for the purpose of improving the printing durability. Heating can be performed by a method of closely contacting a heated object, a method of irradiating infrared rays, or the like. The heating temperature is preferably in the range of 80 to 300 ° C.,
The temperature is more preferably in the range of 100 to 200 ° C. The heating time is preferably from 10 seconds to 10 minutes, more preferably from 20 seconds to 3 minutes.

[0063]

【Example】

[Example 1] (Preparation of image forming material) "Preparation of aluminum support" JI having a thickness of 0.24 mm
The surface of the aluminum plate according to SA-1050 was grained with a nylon brush and an aqueous suspension of pamistone (400 mesh), and then thoroughly washed with water. Next, the substrate was immersed in a 10% by weight aqueous solution of sodium hydroxide at 70 ° C. for 60 seconds for etching, washed with running water, neutralized and washed with a 20% by weight aqueous solution of nitric acid, and then washed with water. The obtained aluminum plate was subjected to a square wave alternating waveform current (condition: voltage at anode: 12.7 v, ratio of electricity at cathode to electricity at anode: 0.9, electricity at anode: 160 coulombs / dm ² ).
Was subjected to electrolytic surface roughening treatment in a 1% by weight aqueous nitric acid solution containing 0.5% by weight of aluminum nitrate. The surface roughness of the obtained plate was 0.6 μm (Ra indication).
Subsequent to this treatment, the substrate was immersed in a 1% by weight aqueous sodium hydroxide solution at 40 ° C. for 30 minutes, and then treated in a 30% by weight aqueous sulfuric acid solution at 55 ° C. for 1 minute. Next, in a 20% by weight aqueous sulfuric acid solution, anodizing treatment is performed using a DC current under a condition of a current density of 2 A / dm ² so that the thickness becomes 2.5 g / dm ² , After drying, an aluminum support was produced.

[Formation of Image Forming Layer] A coating solution having the following composition was coated on the above aluminum support and dried to form an image forming layer having a thickness of about 2.0 μm.

────────────────────────────────────Coating solution for image forming layer────── ────────────────────────────── Methyl methacrylate / methacrylic acid copolymer (copolymerization ratio = 70/30) 0.6 g propylene glycol Monomethyl ether 3.0 g Methyl ethyl ketone 3.0 g Copper phthalocyanine 0.1 g

"Preparation of silver halide emulsion" A solution containing gelatin, potassium bromide and water, and adding sodium hydroxide to adjust the pH at room temperature to 9.5 was heated to 55 ° C. After adding the thioether compound in an amount equivalent to 2.0 × 10 ⁻³ mol with respect to the total amount of silver nitrate, while maintaining the pAg in the reaction vessel at 9.0, the aqueous solution of silver nitrate and the total amount of potassium iodide and silver nitrate were added. An aqueous solution of potassium bromide containing rhodium ammonium chloride was added to pAg so that the molar ratio of rhodium to the amount added was 2 × 10 ⁻⁷ mol.
Silver iodobromide particles were formed by the control double jet method. Subsequently, sulfuric acid was added to adjust the pH to 66.0, and subsequently, at 55 ° C. and pAg = 8.6, an aqueous silver nitrate solution and a molar ratio of iridium to silver of 5 × 10 ^{−7 were used.}
An aqueous solution of potassium bromide to which hexachloroiridate (III) was added in a molar amount was added in two stages by a double jet method to prepare core / shell type silver iodobromide emulsion particles having the following composition.

Core: silver iodobromide (silver iodide content: 8.5 mol%) Shell: pure silver bromide Core / shell ratio: 3/7 (silver molar ratio) Average silver iodide content: 2. 55 mol% average particle size: 0.30 μm

These emulsion grains were monodispersed, and 98% of the total grains were present within ± 40% of the average grain size. Next, the emulsion was desalted, and the pH was adjusted to 6.5 and p
After the Ag was adjusted to 9.0, a methanol solution of the following two types of spectral sensitizing dyes A and B mixed at a 2: 1 molar ratio was added to the dye at 8 × 10 ⁻⁴ while keeping the temperature at 50 ° C. and stirring. It was added in an amount equivalent to mol / mol Ag to obtain a spectrally sensitized emulsion.

[0069]

Embedded image

[0070]

Embedded image

[0071]

Embedded image

[Preparation of Reducing Agent Dispersion] 10 g of the following reducing agent powder was dispersed in 90 g of a 10% by weight aqueous solution of polyvinyl alcohol using a Dynomill disperser.

[0073]

Embedded image

"Preparation of polymerizable compound emulsion" A mixture having the following composition was dispersed with a homogenizer to prepare a polymerizable compound emulsion.

<< Polymerizable Compound Emulsion >> ────────────────────────────── Trimethylolpropane triacrylate (polymerizable compound) 20 g polyvinyl alcohol (degree of saponification 80%) 100 g of a 10% by weight aqueous solution of 2 g of a 5% by weight aqueous solution of the following surfactant ───

[0076]

Embedded image

[Formation of photosensitive layer] A coating solution having the following composition was
Coating and drying on the image forming layer, the film thickness is about 2.
A photosensitive layer of 0 μm was provided.

<< Coating solution for photosensitive layer >> ───────────────────────────── Water 41.0 g 5% by weight aqueous solution of the above surfactant 6.0 g Polyvinyl alcohol (Ken) 47.0 g of a 10% by weight aqueous solution having a degree of conversion of 80%) 58.0 g of the above-mentioned polymerizable compound emulsion 50.0 g of the above-mentioned reducing agent dispersion 20.0 g 33.0 g of a mixture of 10 g of silver halide emulsion and 43 g of water

[0079]

Embedded image

[Preparation of Base Precursor Dispersion] 250 g of the base precursor powder described below was dispersed in 750 g of a 3% by weight aqueous solution of polyvinyl alcohol (80% saponification) using a Dynomill disperser.

[0081]

Embedded image

[Formation of Overcoat Layer] A coating solution having the following composition is applied on the above-mentioned photosensitive layer and dried to form an overcoat layer having a thickness of about 3.5 μm to prepare an image forming material. did.

酸 Acid-modified polyvinyl alcohol (degree of saponification 98%) 100.0 g of a 10 wt% aqueous solution of the above base precursor dispersion 6.0 g 2.0 g of a 5 wt% aqueous solution of the above surfactant ────────────────

(Image Formation) A document (a halftone image for printing: 200 lpi, step wedge) and a band-pass filter (transmitting light having a wavelength of about 670 nm) are adhered to the image forming material, and a xenon flash lamp is used. An image was exposed with an energy amount of ² μJ / cm ² at an exposure time of 10 ⁻⁴ sec. Next, when heat development was performed for 20 seconds on a hot plate heated to 140 ° C. while the support side of the image forming material was in close contact with the hot plate, a silver image was developed on the exposed portions. Next, the image forming material was immersed in a 0.4N aqueous sodium hydroxide solution at room temperature for 10 seconds, and then rubbed with a brush and washed with water. The unexposed portion of the image forming layer was eluted and removed from the support, and the image of the exposed portion was removed. The formation layer remained on the support and a blue image was formed. When printing was performed using this image (printing plate), a good printed matter was obtained.

Example 2 (Preparation of Image Forming Material) "Formation of Image Forming Layer" A 4% by weight methanol solution of sodium hydroxide 1.7 was stirred while a mixed solution having the following composition was stirred.
g was added. This solution was applied on the aluminum support of Example 1 and dried to form an image forming layer having a thickness of about 2.0 μm.

<< Mixed Liquid for Image Forming Layer >> ─────────────────────────────── Methyl methacrylate / methacrylic acid copolymer (copolymerization ratio = 70/30) 0.6 g propylene Glycol monomethyl ether 3.0 g Methyl ethyl ketone 3.0 g Copper phthalocyanine 0.1 g ─

A photosensitive layer and an overcoat layer were provided on the image forming layer in the same manner as in Example 1 to produce an image forming material.

(Image formation) The image forming material was subjected to image exposure and heat development in the same manner as in Example 1. Next, the image forming material was immersed in 0.4N hydrochloric acid at room temperature for 10 seconds, and then rubbed with a brush and washed with water. The image forming layer in the exposed portion was eluted and removed from the support, and the image forming layer in the unexposed portion was removed. A blue image was formed, remaining on the support. When printing was performed using this image (printing plate), a good printed matter was obtained.

Example 3 The image forming material of Example 2 was
Image exposure and heat development were carried out in the same manner as in Example 2. Next, the image-forming material was immersed in a 4.4% by weight aqueous solution of calcium chloride at room temperature for 10 seconds, and then rubbed with a brush and washed with water. Image forming layer remained on the support, and a blue image was formed. When printing was performed using this image (printing plate), a good printed matter was obtained.

Example 4 In the same manner as in Example 1, an image forming layer was provided on a support, and the following coating solution was applied thereon and dried to form a photosensitive layer having a thickness of about 2.3 μm. With
An image forming material was prepared (the overcoat layer was not provided).

<< Coating solution for photosensitive layer >> ───────────────────────────── Water 36.0 g 5% by weight aqueous solution of surfactant of Example 1 6.0 g Polyvinyl alcohol 47.0 g of a 10% by weight aqueous solution (80% saponification degree) 48.0 g of a polymerizable compound emulsion of Example 1 20.0 g of a reducing agent dispersion of Example 1 20.0 g 0.5% by weight of the mercapto compound of Example 1 2.7 g of methanol solution 5.0 g of the base precursor dispersion of Example 1 A mixture of 10 g of the silver halide emulsion of Example 1 and 43 g of water 33.0 g ────────────────────

The image-forming material was exposed to an image in the same manner as in Example 1, and then heat-developed for 20 seconds while the photosensitive layer side of the image-forming material was kept in contact with a hot plate heated to 140 ° C.
Next, when immersed in an aqueous sodium hydroxide solution and washed with water in the same manner as in Example 1, an image similar to that in Example 1 was formed. When printing was performed using this image, a good printed matter was obtained.

Example 5 The image forming material of Example 1 was replaced with
Image exposure, heat development, and immersion in an aqueous sodium hydroxide solution were performed in the same manner as in Example 1. At this stage, most of the image forming layer and the photosensitive layer remained. This was directly mounted on a printing machine without washing, and printing was started. Although the printing ink hardly adhered to the first few sheets, the ink began to adhere rapidly thereafter, and after 20 sheets, as good as in the case of Example 1 (attached to the printing machine after the water washing process), the ink was good. A printed matter was obtained.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of an image forming material used in a preferred embodiment (A) of the image forming method of the present invention.

FIG. 2 is a schematic cross-sectional view showing a state of the image forming material shown in FIG. 1 after completion of image exposure and heat development steps.

FIG. 3 is a schematic cross-sectional view showing a step of applying an aqueous solution of a basic compound to the image forming material for the image forming material shown in FIG.

FIG. 4 is a schematic cross-sectional view showing a result of a reaction between a basic compound and a polymer of an image forming layer in the image forming material shown in FIG.

FIG. 5 is a schematic sectional view showing a step of removing the image forming material shown in FIG. 1 with water.

FIG. 6 is a schematic cross-sectional view showing a state where printing is performed on the image forming material shown in FIG.

FIG. 7 is a schematic cross-sectional view of an image forming material used in another preferred embodiment (B) of the image forming method of the present invention.

FIG. 8 is a schematic cross-sectional view showing a state of the image forming material shown in FIG. 7 after image exposure and heat development steps are completed.

9 is a schematic cross-sectional view showing a step of applying an aqueous solution of an acidic compound to the image forming material shown in FIG. 7;

10 is a schematic cross-sectional view showing a result of a reaction between an acidic compound and a polymer of an image forming layer in the image forming material shown in FIG.

11 is a schematic cross-sectional view showing a step of removing the image forming material shown in FIG. 7 with water.

FIG. 12 is a schematic cross-sectional view showing a state where printing is performed on the image forming material shown in FIG. 7;

[Explanation of symbols]

 11, 71 hydrophilic support 12, 33, 72, 93 image forming layer 13, 73 photosensitive layer 21, 34, 81, 94 exposed part of photosensitive layer 22, 32, 82, 92 unexposed part of photosensitive layer 31 basic Compound 41, 101 Unexposed portion of image forming layer 42, 102 Exposure portion of image forming layer 51, 111 Water 61, 121 Dampening solution 62, 122 Ink 91 Acidic compound

Claims (5)

[Claims] An image-exposing step of exposing an image-forming material in which an image-forming layer containing a polymer and a photosensitive layer containing a silver halide, a reducing agent and an ethylenically unsaturated polymerizable compound are sequentially provided on a support. Heating the image-forming material to cure the exposed portions of the photosensitive layer; applying a liquid containing a reactive substance that reacts with the polymer to the image-forming material, whereby the reactive substance is exposed to unexposed portions of the photosensitive layer; Passing through the polymer to the image forming layer to cause the reactive substance and the polymer to react, thereby denaturing the unexposed portion of the polymer so as to be soluble in the eluate; and forming an image using the eluate. An image forming method, comprising a step of eluting an unexposed portion of the layer and the photosensitive layer, thereby forming an image comprising the remaining image forming layer. 2. An image forming layer containing a water-insoluble polymer having an acidic group and a photosensitive layer containing a silver halide, a reducing agent, an ethylenically unsaturated polymerizable compound and a water-soluble polymer are sequentially provided on a support. Exposing the image forming material to an image; heating the image forming material to cure the exposed portions of the photosensitive layer; applying an aqueous solution of a basic compound to the image forming material, whereby the basic substance is removed from the photosensitive layer. Penetrates through the unexposed portion to the image forming layer, and reacts with the basic substance and the water-insoluble polymer having the acidic group, thereby converting the acidic group of the polymer into a salt state, thereby forming a polymer in the unexposed portion. A step of denaturing the image-forming layer with water; and a step of eluting the unexposed portions and the photosensitive layer of the image-forming layer with water to form an image comprising the remaining image-forming layer. Image forming method. 3. An image-forming step of exposing an image-forming material in which an image-forming layer containing a polymer and a photosensitive layer containing a silver halide, a reducing agent and an ethylenically unsaturated polymerizable compound are sequentially provided on a support. Heating the image-forming material to cure the exposed portion of the photosensitive layer; applying a liquid containing a reactive substance that reacts with the polymer to the image-forming material, whereby the reactive substance is exposed to the unexposed portion of the photosensitive layer; Passing through to the image forming layer to cause the reactive substance and the polymer to react, thereby denaturing the unexposed portion of the polymer to be insoluble in the eluate; and forming an image using the eluate. An image forming method, comprising a step of forming an image comprising a residual image forming layer by dissolving an exposed portion of the layer and the photosensitive layer. 4. An image forming layer comprising a water-soluble polymer having an acidic group in a salt state on a support, and a photosensitive material comprising a silver halide, a reducing agent, an ethylenically unsaturated polymerizable compound and a water-soluble polymer. Image-exposing the image-forming material provided with the layers in sequence; heating the image-forming material to cure the exposed portions of the photosensitive layer; applying an aqueous solution of an acidic compound to the image-forming material, Penetrates through the unexposed portion of the photosensitive layer to the image forming layer, and reacts with the acidic substance and the water-soluble polymer having an acidic group in the form of a salt, whereby the acid in the form of a polymer salt is formed. Denaturing the polymer in the unexposed area to water-insoluble with the group in an acid state; and elute the exposed area and the photosensitive layer of the image forming layer with water to form an image comprising the remaining image forming layer An image forming method, comprising: 5. An image forming layer comprising a water-soluble polymer having an acidic group in the form of a salt with a monovalent cation, a silver halide, a reducing agent, an ethylenically unsaturated polymerizable compound, Image-exposing an image-forming material provided with a photosensitive layer containing a water-soluble polymer in sequence; heating the image-forming material to cure an exposed portion of the photosensitive layer; applying an aqueous solution of a polyvalent metal salt to the image-forming material Whereby the salt of the polyvalent metal passes through the unexposed portion of the photosensitive layer and penetrates to the image forming layer, and the acid in the salt state of the salt of the polyvalent metal and the monovalent cation Reacting with a water-soluble polymer having a group, whereby the polymer is cross-linked to modify the unexposed portion of the polymer to be insoluble in water; and using water to elute the exposed portion and the photosensitive layer of the image forming layer, The remaining image forming layer An image forming method, comprising the step of forming an image comprising: