JP2001228575A - Method for producing heat developable photosensitive material, image recording method and image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat developable photosensitive material which ensures low fog and a good silver tone according to conditions in the production of silver halide grains as a photocatalyst and an organic silver salt as a reducible silver salt. SOLUTION: In the production of a heat developable photosensitive material containing at least a non-photosensitive organic silver salt, photosensitive silver halide, a reducing agent capable of reducing the silver ion of the organic silver salt to silver when activated by heat, a binder and a crosslinking agent for the binder, (1) the photosensitive silver halide in uniformly dispersed in the organic silver salt by mixing the photosensitive silver halide during the formation of the organic silver salt, (2) the concentration of silver ions in a silver halide solution to be added is adjusted to 3×10-10-3×10-9 mol/l and (3) the concentration of silver ions in a reactor immediately after the addition of the silver halide solution is adjusted to 3×10-9-3×10-8 mol/l.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photothermographic material which forms an image by thermal development, and has a high sensitivity, little fogging and a good silver tone, and a method for producing the same. And an image forming method.

[0002]

2. Description of the Related Art In recent years, in the field of printing plate making and medical treatment, a waste liquid accompanying wet processing of an image forming material has become a problem in terms of workability. There is a strong demand for weight loss. Therefore, there is a need for a technology relating to photothermographic materials for photographic technology, which enables efficient exposure with a laser imagesetter or laser imager and can form a high-resolution, clear black image. As this technique, for example, US Pat. Nos. 3,152,904 and 3,487,
No. 075 and D.C. Morgan (Dry Silver Pho)
Graphic Materials) ”(Han
dbook of Imaging Material
s, Marcel Dekker, Inc. Page 48,
1991) is well known. Since these photosensitive materials are usually developed at a temperature of 80 ° C. or higher, they are called photothermographic materials.

[0003] Such a photothermographic material is usually prepared by dispersing a reducible silver source (for example, organic silver salt), a catalytically active amount of a photocatalyst (for example, silver halide) and a reducing agent in an organic binder matrix. Contains and is stable at room temperature,
When heated to a high temperature after exposure, silver is generated by a redox reaction between a reducible silver source (acting as an oxidizing agent) and a reducing agent. This oxidation-reduction reaction is promoted by the catalytic action of the latent image generated by the exposure. The silver formed by the reaction of the organic silver salt in the exposed areas provides a black image, which contrasts with the unexposed areas and results in the formation of an image.

An antifogging agent for controlling the fogging of the image is used in the light-sensitive material as required. The most effective method as a conventional antifogging technique has been a method using a mercury compound as an antifogging agent.

The use of mercury compounds as antifoggants in light-sensitive materials is described, for example, in US Pat.
No. 89,903. However, mercury compounds are environmentally unfavorable, and the development of non-mercury antifoggants has been desired. Non-mercury antifoggants include various polyhalogen compounds (for example, US Pat.
Nos. 874,946, 4,756,999 and 5,340,712, and EP 605,981 A1.
No. 622,666A1, No. 631,176A
No. 1, JP-B-54-165, JP-A-7-2781)
Is disclosed. However, these compounds have problems that the effect of preventing fogging is low and the color tone of silver is deteriorated. Further, those having a high fogging prevention effect have problems such as lowering of sensitivity, and thus need to be improved. Further, there is a problem that the fogging in the unexposed area increases when exposed and developed after the photosensitive material has been laminated and aged under the humidifying and heating conditions, and development of an antifogging agent free of these problems is desired. Was rare.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing a photothermographic material, in which fogging is particularly caused by the conditions for producing silver halide grains as a photocatalyst and organic silver salts as a reducible silver salt. An object of the present invention is to provide a photothermographic material having a low silver tone and a good silver tone.

[0007]

The above objects of the present invention have been attained by the following constitutions.

[0008] 1. At least a non-photosensitive organic silver salt, a photosensitive silver halide, a reducing agent capable of reducing silver ions of the organic silver salt to silver when activated by heat, a binder, a cross-linking material for the binder A method for producing a photothermographic material, comprising: satisfying the following conditions (1) to (3).

(1) dispersing the photosensitive silver halide in an organic silver salt by mixing the photosensitive silver halide during the formation of the non-photosensitive organic silver salt; When silver halide is mixed during the formation of the organic silver salt, the silver ion concentration of the silver halide solution to be added is set to 3 × 10 ⁻¹⁰ mol / L or more and 3 × 10 ⁻⁹ mol / L or less; )
Immediately after the silver halide solution was added, the silver ion concentration in the reaction vessel was 3 × 10 ⁻⁹ mol / L or more and 3 × 10 ⁻⁸ mol / L.
L or less.

2. The heat according to the above 1, wherein the silver ratio of the photosensitive silver halide mixed during the formation of the organic silver salt is 3% or more and 7% or less with respect to the non-photosensitive organic silver salt. A method for producing a developed photosensitive material.

3. The entire process of forming silver halide is carried out at pH
3. The method for producing a photothermographic material according to the above item 1 or 2, wherein the method is carried out at 3 or more and 8 or less.

(4) The angle between the exposed surface of the photothermographic material and the scanning laser beam may be substantially perpendicular to the photothermographic material obtained by the method of any one of (1) to (3). An image recording method comprising performing exposure using a laser exposure machine.

5. Exposure is performed by a laser beam scanning exposure device in which a scanning laser beam for recording an image on the photothermographic material obtained by the production method according to any one of the above items 1 to 3, is a vertical multi. An image recording method comprising:

(6) An image forming method, wherein the photothermographic material obtained by the method according to any one of (1) to (3) is developed by heating at a temperature of 80 ° C. or more and 200 ° C. or less.

Hereinafter, the present invention will be described in more detail. The photosensitive silver halide used in the photothermographic material of the present invention can be produced by any method known in the field of photographic technology such as a single jet or double jet method, for example, an ammonia method emulsion, a neutral method, an acid method, etc. Can also be prepared. Thus, it can be prepared in advance and then mixed with other components of the present invention and introduced into the composition used in the present invention. In this case, in order to sufficiently contact the photosensitive silver halide with the organic silver salt, for example, US Pat.
No. 06,564, No. 3,706,565, No. 3,
No. 713,833, No. 3,748,143 and British Patent No. 1,362,970. Means using a polymer other than gelatin, such as polyvinyl acetal, described in British Patent No. 1,354. Means for Enzymatically Degrading the Gelatin of a Light-Sensitive Silver Halide Emulsion as described in U.S. Pat. No. 4,076,53.
As described in the specification of JP-A No. 9, various means such as a method of omitting the use of a protective polymer by preparing photosensitive silver halide grains in the presence of a surfactant can be applied.

The silver halide functions as an optical sensor and suppresses white turbidity after image formation.
In order to obtain good image quality, those having a small particle size are preferred. 0.1 μm or less in average particle size, preferably 0.01 μm to 0.1 μm, particularly 0.02 μm to 0.0
8 μm is preferred. The shape of the silver halide is not particularly limited, and may be cubic, octahedral, so-called normal crystals, or non-normal crystals, such as spherical, rod-like, or tabular grains. The silver halide composition is not particularly limited, and may be any of silver chloride, silver chlorobromide, silver chloroiodobromide, silver bromide, silver iodobromide, and silver iodide.

The amount of silver halide is preferably from 3% to 7%, more preferably from 5% to 7% in terms of silver ratio with respect to a non-photosensitive organic silver salt described later.

The present invention is characterized in that a photosensitive silver halide formed beforehand during the formation of a non-photosensitive organic silver salt is mixed under certain conditions. As described in British Patent No. 1,447,454, when preparing an organic silver salt, a halogen component such as a halide ion coexists with an organic silver salt-forming component and silver ions are implanted into the mixture. Can be produced almost simultaneously with the production of the organic silver salt.

As still another method, a silver halide forming component is allowed to act on a solution or dispersion of an organic silver salt prepared in advance or a sheet material containing the organic silver salt, and a part of the organic silver salt is exposed to light. It can also be converted to neutral silver halide.
The silver halide thus formed is in effective contact with the organic silver salt and exhibits a preferable action. A silver halide-forming component is a compound capable of forming a photosensitive silver halide by reacting with an organic silver salt, and which compound is applicable and effective is determined by the following simple test. I can do things. That is, an organic silver salt is mixed with a compound to be tested, and if necessary, after heating, it is examined by an X-ray diffraction method whether there is a peak specific to silver halide. Silver halide-forming components confirmed to be effective by such tests include inorganic halides, onium halides, halogenated hydrocarbons, N-halogen compounds, and other halogen-containing compounds. Are U.S. Pat. Nos. 4,009,039 and 3,45
7,075, 4,003,749, British Patent 1,498,956 and JP-A-53-270.
27 and 53-25420, one example of which is shown below.

[0020] (1) inorganic halide: for example halide (where X is a halogen atom represented by MX _n, M
Represents H, NH ₄ , and a metal atom, and n represents 1 when M is H and NH ₄ , and represents its valence when M is a metal atom. Examples of the metal atom include lithium, sodium, potassium, cesium, magnesium, calcium, strontium, barium, zinc, cadmium, mercury, tin, antimony, chromium, manganese, iron, cobalt, nickel, rhodium, and cerium. ). Further, halogen molecules such as bromine water are also effective.

(2) Onium halides: quaternary ammonium halides such as trimethylphenylammonium bromide, cetylethyldimethylammonium bromide and trimethylbenzylammonium bromide, and quaternary phosphonium halides such as tetraethylphosphonium bromide And tertiary sulfonium halides such as trimethylsulfonium iodide.

(3) Halogenated hydrocarbons: for example, iodoform, bromoform, carbon tetrachloride, 2-bromo-2-methylpropane and the like.

(4) N-halogen compounds: For example, N-chlorosuccinimide, N-bromosuccinimide, N-bromophthalimide, N-bromoacetamide, N-iodosuccinimide, N-bromophthalazone, N-bromo Oxazolinone, N-chlorophthalazone, N-bromoacetanilide, N, N-dibromobenzenesulfonamide,
N-bromo-N-methylbenzenesulfonamide, 1,
3-dibromo-4,4-dimethylhydantoin, N-bromourazole and the like.

(5) Other halogen-containing compounds: for example, triphenylmethyl chloride, triphenylmethyl bromide, 2-bromoacetic acid, 2-bromoethanol, dichlorobenzophenone and the like.

These silver halide forming components are used in a small amount stoichiometrically with respect to the organic silver salt. Usually, the range is from 0.001 mol to 0.7 mol, preferably from 0.03 mol to 0.5 mol, per 1 mol of the organic silver salt. Two or more silver halide forming components may be used in combination within the above range. Various conditions such as a reaction temperature, a reaction time, and a reaction pressure in the step of converting a part of the organic silver salt into silver halide using the above-mentioned silver halide forming component can be appropriately set according to the purpose of production. Usually, the reaction temperature is -20 ° C to 70 ° C, the reaction time is 0.1 second to 72 hours,
The reaction pressure is preferably set at atmospheric pressure. This reaction is also preferably performed in the presence of a polymer used as a binder described below. The amount of the polymer used at this time is 0.01 to 100 parts by mass, preferably 0.1 to 10 parts by mass per 1 part by mass of the organic silver salt.

The photosensitive silver halide prepared by the above-mentioned various methods includes, for example, sulfur-containing compounds, gold compounds,
Platinum compounds, palladium compounds, silver compounds, tin compounds,
Chemical sensitization can be achieved by a chromium compound or a combination thereof. The method and procedure of this chemical sensitization are described in, for example, U.S. Pat. No. 4,036,650, British Patent No. 1,518,850, JP-A-51-224.
No. 30, No. 51-78319, and No. 51-81124. Further, when a part of the organic silver salt is converted into a photosensitive silver halide by a silver halide forming component, as described in US Pat. No. 3,980,482, sensitization is achieved. A low molecular weight amide compound may coexist.

In addition, these photosensitive silver halides may be used in order to prevent illuminance failure and to adjust the gradation.
Metals belonging to group III, such as Rh, Ru, Re, Ir, O
An ion such as s or Fe, a complex thereof, or a complex ion can be contained. It is particularly preferable to add as a complex ion. For example, Ir complex ion such as IrCl ₆ ^2- may be added due to illuminance failure.

In the present invention, when the photosensitive silver halide is mixed during the formation of the organic silver salt, the silver ion concentration of the silver halide solution to be added is 3 × 10 ⁻¹⁰ mol / L to 3 × 1.
0 it is necessary to ^-9 mol / L. Further, the silver ion concentration in the reaction vessel immediately after adding the silver halide solution is 3
× set to be 10 ^-9 mol / L~3 × 10 ^-8 mol / L.

In a preferred embodiment of the present invention, the pH of all the steps of forming the photosensitive silver halide is from 3 to 8,
Preferably, it is performed in 4 to 6.

In the present invention, the organic silver salt is a reducible silver source, and is a silver salt of an organic acid or a heteroorganic acid, especially a long chain (10 to 30 carbon atoms, preferably 15 to 2 carbon atoms).
5) Silver salts of aliphatic carboxylic acids and nitrogen-containing heterocyclic compounds are preferred. Organic or inorganic complexes in which the ligand has a value of 4.0 to 10.0 as the total stability constant for silver ions are also preferred. Examples of these suitable silver salts include Res.
Ear Disclosure No. 17029 and 2
9963, and the following may be mentioned.

Silver salts of organic acids, such as gallic acid, oxalic acid,
Silver salts such as behenic acid, stearic acid, arachidic acid, palmitic acid and lauric acid. Silver carboxyalkylthiourea salts, for example, silver salts such as 1- (3-carboxypropyl) thiourea, 1- (3-carboxypropyl) -3,3-dimethylthiourea, and aldehydes with hydroxy-substituted aromatic carboxylic acids Silver salts or complexes of polymer reaction products, for example, aldehydes (formaldehyde, acetaldehyde, butyraldehyde, etc.), hydroxy-substituted acids (for example, salicylic acid, benzoic acid, 3,5-dihydroxybenzoic acid, 5,5-thiodisalicylic acid) A) a silver salt or complex of the reaction product, or a silver salt or complex of a thione, for example,
Silver salts or complexes such as 3- (2-carboxyethyl) -4-hydroxymethyl-4-thiazoline-2-thione and 3-carboxymethyl-4-thiazoline-2-thione;
Imidazole, pyrazole, urazole, 1,2,4-
Thiazole and 1H-tetrazole, 3-amino-5
Complexes or salts of silver and a nitrogen acid selected from benzylthio-1,2,4-triazole and benzotriazole, silver salts such as saccharin and 5-chlorosalicylaldoxime, and silver salts of mercaptides. Among these, preferred silver salts are silver behenate, silver arachidate or silver stearate.

The organic silver salt compound can be obtained by mixing a water-soluble silver compound and a compound which forms a complex with silver, and includes a normal mixing method, a reverse mixing method, a simultaneous mixing method, and a method disclosed in JP-A-9-12764.
A controlled double jet method as described in No. 3 is preferably used. For example, an organic acid alkali metal salt soap (eg, sodium hydroxide, potassium hydroxide, etc.)
Sodium behenate, sodium arachidate, etc.)
The soap and silver nitrate are added to produce organic silver salt crystals. At that time, silver halide grains may be mixed.

In the present invention, the organic silver salt has an average particle size of 2
It is preferably not more than μm and monodispersed. The average particle size of the organic silver salt means that the particles of the organic silver salt are, for example, spherical,
In the case of rod-shaped or tabular grains, it refers to the diameter of a sphere equivalent to the volume of organic silver salt grains. The average particle size is preferably 0.05 μm to 1.5 μm, particularly 0.05 μm.
m to 1.0 μm is preferred. The monodispersion has the same meaning as that of silver halide, and preferably has a monodispersity of 1 to 3.
0.

In the present invention, tabular grains of the organic silver salt preferably have at least 60% of the total organic silver.
In the present invention, the tabular grains have an aspect ratio (abbreviated as AR) represented by the following formula, which is a ratio of the average particle diameter to the thickness, of 3:
The above is mentioned.

AR = average particle size (μm) / thickness (μm) In order to form organic silver into these shapes, the organic silver crystal is obtained by dispersing and grinding a binder, a surfactant and the like with a ball mill or the like. Can be Within this range, a photosensitive material having a high density and excellent image storability can be obtained.

In the present invention, in order to prevent devitrification of the light-sensitive material, the total amount of silver halide and organic silver salt is preferably 0.5 g or more and 2.2 g or less per m ² in terms of silver. . With this range, a high-contrast image can be obtained. The amount of silver halide based on the total amount of silver is 50% or less by mass, preferably 25% or less, and more preferably 0.1% to 15%.

Examples of the reducing agent used in the photothermographic material of the present invention include generally known reducing agents, such as phenols, polyphenols having two or more phenol groups, naphthols, and bisnaphthols. , 2
Polyhydroxybenzenes having at least two hydroxyl groups, 2
Polyhydroxynaphthalenes having at least two hydroxyl groups,
Ascorbic acids, 3-pyrazolidones, pyrazoline-
5-ones, pyrazolines, phenylenediamines, hydroxylamines, hydroquinone monoethers,
Hydroxamic acids, hydrazides, amide oximes, N-hydroxyureas, and the like. More specifically, for example, U.S. Patent Nos. 3,615,533 and 3,67.
9,426, 3,672,904, 3,7
No. 51,252, No. 3,782,949, No. 3,
Nos. 801,321, 3,794,488, 3,893,863, 3,887,376, 3,770,448, 3,819,382,
No. 3,773,512 and No. 3,839,048
No. 3,887,378, No. 4,009,03
9, No. 4,021,240, British Patent No. 1,48
No. 6,148 or Belgian Patent No. 786,086 and JP-A-50-36143, 50-36.
No. 110, No. 50-116023, No. 50-9971
No. 9, No. 50-140113, No. 51-51933
Nos. 51-23721, 52-84727 and JP-B-51-35851, and the present invention is appropriately selected from such known reducing agents. Can be used. As a selection method, the simplest method is to actually prepare a photothermographic material and evaluate the photographic performance of the photothermographic material to determine the superiority of the reducing agent used.

Among the above reducing agents, when an aliphatic silver carboxylate is used as an organic silver salt, preferred reducing agents include polyphenols in which two or more phenol groups are linked by an alkylene group or sulfur. In particular, an alkyl group (eg, methyl group, ethyl group, propyl group, t-butyl group, cyclohexyl group, etc.) or an acyl group (eg, acetyl group, propionyl group, etc.) is provided at at least one of the positions adjacent to the hydroxy substitution position of the phenol group. Are polyphenols in which two or more of the phenol groups substituted by an alkylene group or sulfur, for example, 1,1-bis (2
-Hydroxy-3,5-dimethylphenyl) -3,5
5-trimethylhexane, 1,1-bis (2-hydroxy-3-t-butyl-5-methylphenyl) methane,
1,1-bis (2-hydroxy-3,5-di-t-butylphenyl) methane, (2-hydroxy-3-t-butyl-5-methylphenyl)-(2-hydroxy-5-methylphenyl) Methane, 6,6'-benzylidene-bis (2,4-di-t-butylphenol), 6,6'-benzylidene-bis (2-t-butyl-4-methylphenol), 6,6'-benzylidene- Bis (2,4-dimethylphenol), 1,1-bis (2-hydroxy-
3,5-dimethylphenyl) -2-methylpropane,
1,1,5,5-tetrakis (2-hydroxy-3,5
-Dimethylphenyl) -2,4-ethylpentane, 2,
2-bis (4-hydroxy-3,5-dimethylphenyl) propane, 2,2-bis (4-hydroxy-3,5
U.S. Pat. Nos. 3,589,903 and 4,021,249 or British Patent 1,486,148 and JP-A-51-51933. No. 50-36110, No. 50
Polyphenol compounds described in JP-A-116023, JP-A-52-84727 or JP-B-51-35727, bisnaphthols described in U.S. Pat. No. 3,672,904, for example, 2,2'- Dihydroxy-1,1'-binaphthyl, 6,6'-dibromo-
2,2'-dihydroxy-1,1'-binaphthyl, 6,
6'-dinitro-2,2'-dihydroxy-1,1'-
Binaphthyl, bis (2-hydroxy-1-naphthyl) methane, 4,4'-dimethoxy-1,1'-dihydroxy-2,2'-binaphthyl and the like, and further US Pat. No. 3,80
Sulfonamidophenols or sulfonamidonaphthols as described in US Pat. No. 1,321, for example, 4-benzenesulfonamidophenol, 2-benzenesulfonamidophenol, 2,6-dichloro-4
-Benzenesulfonamidophenol, 4-benzenesulfonamidonaphthol and the like.

The amount of the reducing agent used in the photothermographic material of the present invention varies depending on the type of the organic silver salt, the reducing agent, and other additives. The suitable amount is from 05 mol to 10 mol, preferably from 0.1 mol to 3 mol. Further, within this range, two or more of the above-mentioned reducing agents may be used in combination.

In the photothermographic material of the present invention, it is desirable to use an additive called a color tone agent, a color tone imparting agent or an activator toner (hereinafter referred to as a color tone agent) together with the above-mentioned components. The color tone agent has a function of participating in the oxidation-reduction reaction between the organic silver salt and the reducing agent to make the resulting silver image dark, particularly black. Examples of suitable toning agents for use in the present invention are Research Disclosure No. 1702
No. 9 and the following.

Imides (eg phthalimide); cyclic imides, pyrazolin-5-ones, and quinazolinones (eg succinimide, 3-phenyl-2-pyrazolin-5-one, 1-phenylurazole, quinazoline and 2 , 4-thiazolidinedione); naphthalimides (eg, N-hydroxy-1,8-naphthalimide); cobalt complexes (eg, hexamine trifluoroacetate of cobalt), mercaptans (eg, 3
-Mercapto-1,2,4-triazole); N- (aminomethyl) aryldicarboximides (for example,
N- (dimethylaminomethyl) phthalimide); blocked pyrazoles, isothiuronium (isoth
uronium) derivatives and certain photobleaches (eg, N, N'-hexamethylene (1-carbamoyl-3,5-dimethylpyrazole), 1,8-
A combination of (3,6-dioxaoctane) bis (isothiuronium trifluoroacetate) and 2- (tribromomethylsulfonyl) benzothiazole; a merocyanine dye (e.g., 3-ethyl-5-((3-ethyl -2-benzothiazolinylidene (benzothiazolinylidene))-1-methylethylidene) -2-thio-2,4
Oxazolidinedione); phthalazinone, a phthalazinone derivative or a metal salt of these derivatives (for example, 4-
(1-naphthyl) phthalazinone, 6-chlorophthalazinone, 5,7-dimethyloxyphthalazinone, and 2,3
-Dihydro-1,4-phthalazinedione); a combination of phthalazinone and a sulfinic acid derivative (for example, 6-chlorophthalazinone + sodium benzenesulfinate or 8-methylphthalazinone + sodium p-trisulfonate); phthalazine + phthalate Acid combinations; phthalazine (including phthalazine adducts) and maleic anhydride,
And phthalic acid, 2,3-naphthalenedicarboxylic acid or o
At least one selected from phenylene acid derivatives and anhydrides thereof (for example, phthalic acid, 4-methylphthalic acid, 4-nitrophthalic acid and tetrachlorophthalic anhydride);
Quinazolinediones, benzoxazines, naphthoxazine derivatives; benzoxazine-2,4-diones (eg, 1,3-benzoxazine-2,4-dione); pyrimidines and asymmetric triazines (Eg, 2,4-dihydroxypyrimidine) and tetraazapentalene derivatives (eg, 3,
6-dimercapto-1,4-diphenyl-1H, 4H-
2,3a, 5,6a-tetraazapentalene). Preferred toning agents are phthalazone or phthalazine.

Binders suitable for the photothermographic material of the present invention are transparent or translucent and generally colorless, and include natural polymers, synthetic polymers and copolymers, and other film-forming media such as gelatin, gum arabic and polyvinyl alcohol. , Hydroxyethyl cellulose, cellulose acetate, cellulose acetate butyrate, polyvinylpyrrolidone, casein, starch, polyacrylic acid, polymethyl methacrylate, polymethacrylic acid, polyvinyl chloride, copoly (styrene-maleic anhydride),
Copoly (styrene-acrylonitrile), copoly (styrene-butadiene), polyvinylacetals such as polyvinylformal, polyvinylbutyral, polyesters, polyurethanes, phenoxy resins, polyvinylidene chloride, polyepoxides, polycarbonates, polyvinyl acetates, cellulose Esters,
There are polyamides and the like, which may be hydrophilic or non-hydrophilic. However, among these binders, particularly preferred are water-insoluble polymers such as cellulose acetate, cellulose acetate butyrate and polyvinyl butyral, and among them, polyvinyl butyral is particularly preferred.

In the present invention, the binder amount of the photosensitive layer is preferably 1.5 to 6 g / m ² . More preferably, it is 1.7 to 5 g / m ² . If it is less than 1.5 g / m ² , the density of the unexposed portion will increase significantly and may not be usable.

In the present invention, a matting agent is preferably contained on the photosensitive layer side, and a matting agent is preferably provided on the surface of the photosensitive material in order to prevent damage to the image after thermal development. It is preferable that the composition contains the agent in an amount of 0.5 to 30% by mass based on all binders on the photosensitive layer side.

When a non-photosensitive layer is provided on the opposite side of the photosensitive layer with the support interposed therebetween, it is preferable that at least one layer on the non-photosensitive layer side contains a matting agent, so that the light-sensitive material has slipperiness and fingerprint adhesion. For prevention, it is preferable to provide a matting agent on the surface of the photosensitive material, and the matting agent is added in a mass ratio of 0.5 to 4 with respect to all binders of the layer on the side opposite to the photosensitive layer side.
It is preferable to contain 0%.

The material of the matting agent used in the present invention may be either an organic substance or an inorganic substance. For example, inorganic substances include silica described in Swiss Patent No. 330,158, glass powder described in French Patent No. 1,296,995, etc., and alkali described in British Patent No. 1,173,181 and the like. An earth metal or a carbonate such as cadmium or zinc can be used as a matting agent. As organic matter,
Starch described in U.S. Pat. No. 2,322,037, Belgian Patent 625,451 and British Patent 981,19
No. 8 and the like, and starch derivatives described in JP-B-44-3643.
No. 33, Swiss Patent No. 33
No. 0,158, polystyrene or polymethacrylate; U.S. Pat. No. 3,079,257; polyacrylonitrile; U.S. Pat. No. 3,022,16.
An organic matting agent such as polycarbonate described in No. 9 or the like can be used.

The shape of the matting agent may be either regular or irregular, but is preferably regular and spherical. The size of the matting agent is represented by a diameter when the volume of the matting agent is converted into a sphere. In the present invention, the particle diameter of the matting agent indicates the diameter converted into a sphere.

The matting agent used in the present invention preferably has an average particle size of 0.5 μm to 10 μm, more preferably 1.0 μm to 8.0 μm. The matting agent preferably has a variation coefficient of the particle size distribution of 50% or less, more preferably 40% or less, and particularly preferably 30% or less.

Here, the variation coefficient of the particle size distribution is a value represented by the following equation. (Standard deviation of particle size) / (average value of particle size) × 100 The matting agent according to the present invention can be contained in any constituent layer, but is preferably photosensitive in order to achieve the object of the present invention. It is a constituent layer other than the layer, more preferably the outermost layer as viewed from the support.

The method for adding the matting agent according to the present invention may be a method in which the matting agent is dispersed in a coating solution in advance and applied.
A method of spraying a matting agent after the application liquid is applied and before the drying is completed may be used. When a plurality of types of matting agents are added, both methods may be used in combination.

The photothermographic materials of the present invention include, for example, JP-A-63-159814, JP-A-60-140335 and JP-A-6-140335.
Nos. 3-231437, 63-259651 and 63
-304242, 63-15245, U.S. Patent Nos. 4,639,414, 4,740,455, 4,741,966, 4,751,175,
Sensitizing dyes described in the above-mentioned 4,835,096 can be used. Useful sensitizing dyes for use in the present invention include, for example, R
search Disclosure Item 1
7643 IV-A (December 1978, p. 23). In particular, a sensitizing dye having a spectral sensitivity suitable for the spectral characteristics of various scanner light sources can be advantageously selected. For example, for an argon ion laser light source, see JP-A-60-162247.
No. 2,486,635, U.S. Pat.
No. 331, West German Patent No. 936,071, JP-A-5-1
JP-A-50-624 describes simple merocyanines and helium neon laser light sources described in US Pat.
No. 25, No. 54-18726, No. 59-102229
Trinuclear cyanine dyes disclosed in JP-A-7-2873
JP-B-48-4217 discloses merocyanines, LED light sources and infrared semiconductor laser light sources described in JP-A-38.
No. 2, No. 51-9609, No. 55-39818, JP-A Nos. 62-284343 and 2-105135, and JP-A No. 2-105135 discloses a thiacarbocyanine and infrared semiconductor laser light source. Tricarbocyanines described in JP-A-59-191032 and JP-A-60-80841; JP-A-59-192242; JP-A-3-6724.
Dicarbocyanines containing a 4-quinoline nucleus described in No. 2 in the general formulas (IIIa) and (IIIb) are advantageously selected. Further, when the wavelength of the infrared laser light source is 750 nm or more, more preferably 800 nm or more.
No. 39, No. 5-341432, Tokuhei 6-52387
No. 3-10931, U.S. Pat. No. 5,441,86
No. 6, sensitizing dyes described in JP-A-7-13295 and the like are preferably used. These sensitizing dyes may be used alone, and a combination of sensitizing dyes is often used particularly for supersensitization. Along with the sensitizing dye, the emulsion may contain a dye which does not itself have a spectral sensitizing effect or a substance which does not substantially absorb visible light and exhibits supersensitization.

The photothermographic material of the present invention has at least one photosensitive layer on a support. Although only the photosensitive layer may be formed on the support, it is preferable to form at least one non-photosensitive layer on the photosensitive layer. A filter layer may be formed on the same side as the photosensitive layer or on the opposite side to control the amount or wavelength distribution of light transmitted to the photosensitive layer, or the photosensitive layer may contain a dye or pigment. Good. As the dye, compounds described in JP-A-8-201959 are preferred. The photosensitive layer may be composed of a plurality of layers, or a high-sensitivity layer and a low-sensitivity layer may be provided for adjusting the gradation, and these layers may be combined. Various additives may be added to any of the photosensitive layer, the non-photosensitive layer, and other forming layers. The photothermographic material of the present invention may contain, for example, a surfactant, an antioxidant, a stabilizer, a plasticizer, an ultraviolet absorber, and a coating aid.

Exposure of the photothermographic material of the present invention is performed by using an argon ion laser (488 nm), a He—Ne laser (633 nm), a red semiconductor laser (670 nm),
An infrared semiconductor laser (780 nm, 820 nm) or the like is preferably used, but an infrared semiconductor laser is more preferably used from the viewpoint that the laser power is high and the photosensitive material can be made transparent.

In the present invention, it is preferable to use a laser scanning exposure machine in which the angle between the exposure surface of the photosensitive material and the scanning laser beam does not become substantially perpendicular.

Here, "not substantially vertical" means that the angle is most vertical during laser scanning, preferably 55 to 88 degrees, more preferably 60 to 86 degrees, and still more preferably. Means 65 ° to 84 °, most preferably 70 ° to 82 °.

The beam spot diameter on the exposed surface of the photosensitive material when the laser light is scanned on the photosensitive material is preferably 200 μm or less, more preferably 100 μm or less. It is preferable that the spot diameter is small in that the shift angle of the laser incident angle from the perpendicular can be reduced.

The lower limit of the beam spot diameter is 10 μm.
m. By performing such laser scanning exposure, it is possible to reduce image quality deterioration related to reflected light such as occurrence of unevenness like interference fringes.

It is also preferable that the exposure in the present invention is performed using a laser scanning exposure machine that emits a scanning laser beam which is a vertical multi. Image quality deterioration such as generation of interference fringe-like unevenness is reduced as compared with the scanning laser beam in the longitudinal single mode.

For the vertical multiplication, a method of combining, using return light, or superimposing a high frequency is preferable.
In addition, the vertical multi means that the exposure wavelength is not single, and the distribution of the exposure wavelength is usually 5 nm or more, preferably 10 nm or more.
nm or more. The upper limit of the exposure wavelength distribution is not particularly limited, but is usually about 60 nm.

The photothermographic material of the present invention is stable at room temperature, but is developed by heating to high temperature after exposure. The heating temperature is preferably from 80 ° C. to 200 ° C., and more preferably from 100 ° C. to 150 ° C. If the heating temperature is lower than 80 ° C., a sufficient image density cannot be obtained in a short time, and if the heating temperature is higher than 200 ° C., the binder is melted and adversely affects not only the image itself but also transportability such as transfer to a roller and a developing machine. Effect. By heating, a silver image is generated by an oxidation-reduction reaction between an organic silver salt (functioning as an oxidizing agent) and a reducing agent. This reaction process proceeds without supply of a processing liquid such as water from the outside.

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EXAMPLES Example 1 Preparation of Photosensitive Silver Halide Emulsion 1 A1 Phenylcarbamoyl gelatin 88.3 g Compound (A) (10% methanol solution) 10 ml Potassium bromide 0.32 g Finished to 5429 ml with water B1 0.67 N silver nitrate Aqueous solution 2635 ml C1 Potassium bromide 51.55 g Potassium iodide 1.47 g Make up to 660 ml with water D1 Potassium bromide 154.9 g Potassium iodide 4.41 g Iridium chloride (1% solution) 0.93 ml E1 0.4N potassium bromide Aqueous solution The following silver potential control amount F1 56% acetic acid aqueous solution 16.0 ml G1 1.72 g of anhydrous sodium carbonate Finish up to 151 ml with water Compound (A): HO (CH ₂ CH ₂ O) _n- [CH (CH ₃ ) CH ₂ O ] <sub>17
- (CH 2 CH 2 O)</sub> m Hm + n = 5~7 B No. 58-58288, a solution (A1) with a mixing and stirring machine shown in Nos. 58-58289 solution (B1)
Of the solution (C1) at 45 ° C. and pAg8.
While controlling to 09, the addition was carried out by the simultaneous mixing method in 4 minutes and 45 seconds to form nuclei.

After a lapse of 7 minutes, the remaining amount of the solution (B1) and the total amount of the solution (D1) were controlled to 45.degree.
It was added over 4 minutes and 15 seconds. During the mixing, the pH of the reaction solution was 5.6.

After stirring for 5 minutes, the temperature was lowered to 40 ° C., the whole amount of the solution (F1) was added, and the silver halide emulsion was precipitated. The supernatant was removed, leaving 2000 ml of sedimentation,
After adding 10 L of water and stirring, the silver halide was precipitated again. The supernatant was removed, leaving 1500 ml of the sedimented portion, and 10 L of water was further added. After stirring, the silver halide was sedimented. After removing the supernatant liquid leaving 1500 ml of the sedimented portion, the solution (G1) was added, the temperature was raised to 60 ° C., and the mixture was further stirred for 120 minutes. Finally, the pH was adjusted to 5.8, and water was added so as to be 1161 g per mol of silver.

This emulsion had an average grain size of 0.058 μm.
m, coefficient of variation of particle size 12%, [100] face ratio 9
It was 2% cubic silver iodobromide grains.

Preparation of Powdered Organic Silver Salt 130.8 g of behenic acid, 67.7 g of arachidic acid, 43.6 g of stearic acid and 2.3 g of palmitic acid were dissolved in 4720 ml of pure water at 80 ° C. Next, while stirring at a high speed, 540.2 ml of a 1.5 M aqueous sodium hydroxide solution was added, 6.9 ml of concentrated nitric acid was added, and the mixture was cooled to 55 ° C. to obtain a sodium organic acid solution.

The temperature of the above-mentioned organic acid sodium salt solution was 55
While maintaining the temperature at ° C, an emulsion solution having the silver ion concentration shown in Table 1 by adding KBr to the photosensitive silver halide emulsion 1 and 450 ml of pure water was added and stirred for 5 minutes.
At this time, the photosensitive silver halide emulsion 1 was added so that the silver amount was 5% with respect to the finally formed organic silver salt.
Further, the silver ion concentration in the reaction vessel after the addition of the silver halide emulsion was adjusted to the value shown in Table 1.

Next, 760.6 ml of a 1 M silver nitrate solution was added to 2
The mixture was added over a period of 20 minutes, stirred for another 20 minutes, and the water-soluble salts were removed by filtration. Then, the conductivity of the filtrate is 20 μS
/ Cm was repeated by washing with deionized water and filtration, centrifugal dehydration was performed, and then hot air drying was performed at 37 ° C. until there was no loss in mass to obtain a powdered organic silver salt.

Further, in the above step, after the silver halide emulsion solution was formed into an organic silver salt, a powdered organic silver salt added before removing the water-soluble salts was simultaneously prepared.

Preparation of Preliminary Dispersion Polyvinyl butyral powder (manufactured by Monsanto, B
utvar B-79) was dissolved in 1457 g of methyl ethyl ketone, and 500 g of each of the obtained powdered organic silver salts was gradually added and mixed well while stirring with a dissolver DISPERMAT CA-40M manufactured by VMA-GETZMANN. Thus, a preliminary dispersion was prepared.

Preparation of Photosensitive Emulsion Dispersion Each of the pre-dispersions was pumped using a pump so that 0.5 mm-diameter zirconia beads (Treceram, manufactured by Toray Industries Co., Ltd.) accounted for 80% of the internal volume so that the stagnation time in the mill was 10 minutes. Filled media type disperser DISPERMAT SL-CI2EX type (VM
A-GETZMANN), mill peripheral speed 13m
/ Sec to prepare a photosensitive emulsion dispersion.

Preparation of Stabilizer Solution 1.0 g of Stabilizer 1 and 0.31 g of potassium acetate were dissolved in 4.97 g of methanol to prepare a stabilizer solution.

Preparation of Infrared Sensitizing Dye Solution 19.2 mg of infrared sensitizing dye 1, 1.488 g of 2-chloro-benzoic acid, 2.779 g of stabilizer 2 and 365
mg of 5-methyl-2-mercaptobenzimidazole was dissolved in 31.3 ml of MEK in a dark place to prepare an infrared sensitizing dye solution.

Preparation of Additive Solution a 27.98 g of Developer A-3, 1.54 g of 4-methylphthalic acid, and 0.48 g of Infrared Dye 1 were dissolved in 110 g of MEK to obtain Additive Solution a.

Preparation of Additive Solution b 3.56 g of the antifoggant 2, 3.43 g of phthalazine were dissolved in 40.9 g of MEK to obtain an additive solution b.

Preparation of Photosensitive Layer Coating Solution Each photosensitive emulsion dispersion (50 g) and MEK 15.11
g was kept at 21 ° C. while stirring, and the antifoggant 1 (1
(0% methanol solution) (390 μl) was added and stirred for 1 hour. Calcium bromide (10% methanol solution) 4
94 μl was added and stirred for 20 minutes. Then, after adding 167 mg of stabilizer liquids and stirring for 10 minutes, 2.622
g of the infrared sensitizing dye solution was added and stirred for 1 hour. Thereafter, the temperature was lowered to 13 ° C., and the mixture was further stirred for 30 minutes.
While keeping the temperature at 13 ° C, polyvinyl butyral (Mon
Santo Butvar B-79) 13.31 g
After stirring for 30 minutes, 1.084 g of tetrachlorophthalic acid (9.4 mass% MEK solution) was added,
Stir for another 15 minutes. While continuing stirring, 1
2.43 g of additive solution a, 1.6 ml of Desmodur
N3300 / Mobay's aliphatic isocyanate (1
(0% MEK solution), 4.37 g of the additive solution b was sequentially added and stirred to obtain a photosensitive layer coating solution.

Preparation of Matting Agent Dispersion Cellulose acetate butyrate (Eastman C)
Chemical Corporation, 7.5 g of CAB171-15) was dissolved in 42.5 g of MEK, and calcium carbonate (Specialty Minerals, Sup.) was dissolved therein.
er-Pflex 200) was added thereto, and dispersed by a dissolver-type homogenizer at 8,000 rpm for 30 minutes to prepare a matting agent dispersion.

Preparation of Coating Solution for Surface Protective Layer While stirring 865 g of MEK, cellulose acetate butyrate (Eastman Chemical Co., CA)
B171-15): 96 g, polymethylmethacrylic acid (Rohm & Haas Co., Paraloid A-21): 4.5
g, vinyl sulfone compound (HD-1): 1.5 g, benzotriazole: 1.0 g, F-based activator (Asahi Glass Co., Ltd.
Surflon KH40): 1.0 g was added and dissolved.
Next, 30 g of a matting agent dispersion was added and stirred to prepare a surface protective layer coating solution.

Coating on the photosensitive layer surface side Each of the above-mentioned photosensitive layer coating solution and surface protective layer coating solution was extruded and simultaneously subjected to multilayer coating using a coater. The coating was performed so that the photosensitive layer had a coated silver amount of 1.9 g / m ² and the surface protective layer had a dry film thickness of 2.5 μm. Thereafter, drying was performed for 10 minutes using a drying air having a drying temperature of 75 ° C. and a dew point temperature of 10 ° C.

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Exposure and development treatment From the emulsion side of the photosensitive material prepared as described above, exposure by laser scanning was performed with an exposure machine using a semiconductor laser which was made a vertical multi-mode with a wavelength of 800 nm to 820 nm by a high frequency superimposition as a light emitting source. Gave. At this time, an image was formed with the angle between the exposure surface of the photosensitive material and the exposure laser beam being 75 degrees. (Note that an image having less unevenness and unexpectedly good sharpness was obtained compared to the case where the angle was set to 90 degrees.) Thereafter, the protective layer of the photosensitive material was formed using an automatic developing machine having a heat drum. The film was subjected to a heat development treatment at 110 ° C. for 15 seconds so that the drum and the drum surface were in contact with each other. At that time, exposure and development were performed in a room conditioned at 23 ° C. and 50% RH.
The obtained image was evaluated using a densitometer. The results of the measurement were evaluated in terms of sensitivity (the reciprocal of the ratio of the exposure amount giving a density higher than that of the unexposed portion by 1.0) and fog, and are shown in Table 1 as relative values with the sensitivity of the photosensitive material 1 being 100.

Evaluation of Silver Tone For evaluation of silver tone, the density after development was 1.1 ± 0.0
A sample which was exposed and developed so as to obtain No. 5 was prepared. This sample was irradiated for 10 hours, 100 hours, and 1000 hours with a light source having a color temperature of 7,700 Kelvin and an illuminance of 1,1600 lux, and the silver color tone was evaluated based on the following criteria. The number of ranks that has no problem in quality assurance is 4 or more.

Evaluation criteria 5: Pure black tone and no yellowness felt 4: Not pure black but almost no yellowness 3: Partially slightly yellowish 2: Slightly yellowish over the entire surface Feel 1: At first glance, yellow is felt. Table 1 shows the results.

[0084]

[Table 1]

From Table 1, it can be seen that the sample according to claim 1 of the present invention is a photothermographic material having low fog and good silver tone.

Example 2 A photosensitive material was prepared and evaluated in exactly the same manner as in Example 1 except that the amount of the silver halide emulsion was changed to the amount shown in Table 2 in the preparation process of the powdered organic silver salt. Table 2 shows the results.

[0087]

[Table 2]

From Table 2, it can be seen that the sample according to claim 2 of the present invention is a photothermographic material having low fog and good silver tone.

Example 3 A photosensitive material was prepared and evaluated in exactly the same manner as in Example 1 except that, after the nucleation was completed, the pH was adjusted as shown in Table 3 in the preparation step of the photosensitive silver halide. A potassium hydroxide solution or an acetic acid solution was used for pH adjustment during the preparation of silver halide. Table 3 shows the results.

[0090]

[Table 3]

Table 3 shows that the sample according to claim 3 of the present invention is a photothermographic material having low fog and good silver tone.

[0092]

According to the present invention, it is possible to provide a photothermographic material having a low fog and a good silver tone by the production conditions of silver halide grains as a photocatalyst and organic silver salts as a reducible silver salt. did it.

Claims (6)

[Claims] At least a non-photosensitive organic silver salt, a photosensitive silver halide, a reducing agent capable of reducing silver ions of the organic silver salt to silver when activated by heat, a binder, and crosslinking of the binder A method for producing a photothermographic material comprising a material, wherein the following conditions (1) to (3) are satisfied. (1) dispersing the photosensitive silver halide in the organic silver salt by mixing the photosensitive silver halide during the formation of the non-photosensitive organic silver salt; When mixing during the formation of the organic silver salt, the silver ion concentration of the added silver halide solution is adjusted to 3
× 10 ^-10 mol / L or more, 3 × 10 ^-9 mol / L to below, (3) the silver halide solution of silver ion concentration in the reaction vessel immediately after the addition of 3 × 10 ^-9 mol / L or more, 3 × 10 ^-8
Mol / L or less. 2. The photosensitive silver halide mixed during the formation of the organic silver salt has a silver ratio of 3% or more and 7% or less with respect to the non-photosensitive organic silver salt. Production method of photothermographic material. 3. The process for forming silver halide is carried out at pH 3
3. The method for producing a photothermographic material according to claim 1, wherein the process is carried out at 8 or less. 4. An angle between an exposed surface of the photothermographic material and the scanning laser beam is substantially perpendicular to the photothermographic material obtained by the method according to claim 1. An image recording method comprising performing exposure using a laser exposure machine that does not cause a problem. 5. A method for recording an image on a photothermographic material obtained by the method according to claim 1, wherein the laser beam is exposed by a laser beam scanning exposure device having a vertical multi-scan laser beam. An image recording method characterized by performing. 6. An image forming method, wherein the photothermographic material obtained by the production method according to claim 1 is developed by heating at a temperature of 80 ° C. or more and 200 ° C. or less. Method.