JPH11125880A - Production of thermal image forming material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the state of a coated surface without deteriorating a photographic performance by mixing an org. silver salt and a polymer latex in a coating liq., then, making the resultant coating liq. elapse for a specified time and thereafter, coating the coating liq. on a substrate. SOLUTION: After an org. silver salt and a polymer latex are mixed in a coating liq., the resultant coating liq. is made to elapse for 30 min to 24 hr and a thermal image forming layer is coated by using the coating liq. In this case, since the state of the coated surface is deteriorated when the temperature to be made the coating liq. to elapse is too low after mixing the salt and the latex and there is a problem that fagging increases at an excessively high temp., the coating liq. is preferably made to elapse at 30-65 deg.C, more preferably at 35-60 deg.C, particularly preferably at 35-55 deg.C. A coating liq. preparation tank may be kept warm so as to maintain the temp.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a thermal image forming material.

[0002]

2. Description of the Related Art In recent years, there has been a strong demand in the medical field to reduce the amount of waste liquid from the viewpoint of environmental protection and space saving. Therefore, a photosensitive heat for medical diagnostics and photographic technology can be efficiently exposed by a laser imagesetter or a laser imager and can form a clear black image having high resolution and sharpness. There is a need for technology for developed photographic materials. These photothermographic materials can eliminate the use of solution processing chemicals and provide a simpler and more environmentally friendly thermal development system to customers.

There is a similar demand in the field of general image forming materials. However, medical images require high-quality images with excellent sharpness and granularity due to the need for fine depiction. From the viewpoint, there is a feature that a cool tone image is preferred. At present, various hard copy systems using pigments and dyes such as ink jet printers and electrophotographs are generally distributed as modeling systems, but none of them are satisfactory as medical image output systems.

On the other hand, a thermal image forming system using an organic silver salt is disclosed in many documents including US Pat. No. 2,910,377 and Japanese Patent Publication No. 43-4924. The thermal image forming system using these organic silver salts can achieve image quality and color tone that are satisfactory as medical images. However, in many cases, the surface state is poor due to application of an organic solvent. There is also a coating using an aqueous dispersion of a polymer latex, but this also has a poor surface condition, and improvement is desired.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing a thermal image forming material having an excellent surface condition.

[0006]

This object has been achieved by the following means. (1) In a method for producing a thermal image forming material in which a coating solution for a thermal image forming layer containing an organic silver salt and a polymer latex is coated and dried on a support, an organic silver salt and a polymer latex are mixed with the coating solution. A method for producing a thermal image forming material, characterized in that the coating liquid is applied to a support after 30 minutes to 24 hours.

(2) The method according to claim 1, wherein after the organic silver salt and the polymer latex are mixed in the coating solution, the coating is carried out at 30 ° C. to 65 ° C. for 30 minutes to 24 hours. A method for producing a thermal image forming material.

(3) 50% of the solvent of the coating solution for the thermal image forming layer
The method for producing a thermal image forming material according to claim 1 or 2, wherein water is water.

(4) The polymer latex is an aqueous dispersion, and the polymer has an equilibrium water content at 25 ° C. and 60% RH of 0.01% by weight or more and 2% by weight or less. 4. The method for producing a thermal image forming material according to 2 or 3.

(5) The method for producing a thermal image forming material according to any one of claims 1 to 4, wherein the thermal image forming layer contains a reducing agent for a photosensitive silver halide and an organic silver salt. .

(6) The method according to any one of claims 1 to 5, wherein the organic silver salt is an organic carboxylic acid silver salt.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
The coating of the thermal development layer containing the organic silver salt and the polymer latex in the present invention uses a coating solution that has been mixed for 30 minutes or more and 24 hours or less after mixing the organic silver salt and the polymer latex. Preferably, a coating solution that has been mixed for 60 minutes to 12 hours, and more preferably 120 minutes to 10 hours after mixing is used. Here, "after mixing" means after the organic silver salt and the polymer latex have been added and the added materials have been uniformly dispersed.

Regarding the order of the organic silver salt and the polymer latex, any of them may be added first, or they may be added simultaneously. Preferably, the polymer latex is later. In the present invention, it is preferable that an organic silver salt and further a reducing agent are mixed before the addition of the polymer latex.

In the present invention, after the organic silver salt and the polymer latex are further mixed, if the temperature at which aging is performed is too low, the coated surface state is impaired, and if the temperature is too high, there is a problem that fogging increases. The liquid is preferably aged at 30 ° C. or more and 65 ° C. or less for the above-mentioned time. More than 35 ℃
The aging is preferably performed at a temperature of 60 ° C. or less, particularly preferably at a temperature of 35 ° C. or more and 55 ° C. or less. In order to maintain the temperature in this manner, it is only necessary to keep the temperature of the coating solution preparation tank or the like.

The coating solution for the image forming layer of the thermal image forming material in the present invention may be applied and dried by any method.
Specifically, various coating operations are used, including extrusion coating, slide coating, curtain coating, dip coating, knife coating, flow coating, or extrusion coating using a hopper of the type described in U.S. Patent No. 2,681,294. Stephen F. Kistler, Petert M. Schweizer
By "LIQUID FILM COATING" (published by CHAPMAN & HALL, 199
(7 years) Extrusion coating or slide coating described on pages 399 to 536 is preferably used, and particularly preferably slide coating is used. An example of the shape of a slide coater used for slide coating is shown in FIG. If desired, two or more layers can be simultaneously coated by the method described on pages 399 to 536 of the same book, the method described in US Pat. No. 2,761,791 and British Patent No. 837,095.

The organic silver salt that can be used in the present invention includes:
Relatively stable to light, but in the presence of an exposed photocatalyst (such as a latent image of photosensitive silver halide) and a reducing agent,
A silver salt that forms a silver image when heated to 80 ° C. or higher. The organic silver salt can be any organic substance including a source capable of reducing silver ions. Silver salts of organic acids, especially silver salts of organic carboxylic acids, particularly silver salts of long-chain fatty carboxylic acids (having 10 to 30 carbon atoms, preferably 15 to 28 carbon atoms) are preferred. Complexes of organic or inorganic silver salts whose ligands have a complex stability constant in the range of 4.0 to 10.0 are also preferred. The silver donor material can preferably comprise about 5-70% by weight of the imaging layer. Preferred organic silver salts include silver salts of organic compounds having a carboxyl group. Examples of these include, but are not limited to, silver salts of aliphatic carboxylic acids and silver salts of aromatic carboxylic acids. Preferred examples of the silver salt of an aliphatic carboxylic acid include silver behenate, silver arachidate, silver stearate, silver oleate, silver laurate, silver caproate,
Silver myristate, silver palmitate, silver maleate, silver fumarate, silver tartrate, silver linoleate, silver butyrate and silver camphorate, and mixtures thereof.

Silver salts of compounds containing a mercapto group or a thione group and derivatives thereof can also be used. Preferred examples of these compounds include 3-mercapto-4-
Silver salt of phenyl-1,2,4-triazole, silver salt of 2-mercaptobenzimidazole, silver salt of 2-mercapto-5-aminothiadiazole, silver salt of 2- (ethylglycolamide) benzothiazole, S-alkylthio Silver salts of thioglycolic acid, such as silver salts of glycolic acid (where the alkyl group has 12 to 22 carbon atoms); silver salts of dithiocarboxylic acids, such as silver salts of dithioacetic acid; silver salts of thioamide; Silver salt of carboxyl-1-methyl-2-phenyl-4-thiopyridine, silver salt of mercaptotriazine, silver salt of 2-mercaptobenzoxazole, silver salt described in U.S. Pat.No. 4,123,274,
For example, a silver salt of a 1,2,4-mercaptothiazole derivative such as a silver salt of 3-amino-5-benzylthio-1,2,4-thiazole,
Silver salts of thione compounds such as the silver salt of 3- (3-carboxyethyl) -4-methyl-4-thiazoline-2-thione described in U.S. Pat. No. 3,301,678. Furthermore, compounds containing an imino group can also be used. Preferred examples of these compounds include silver salts of benzotriazole and derivatives thereof, for example, silver salts of benzotriazole such as silver methylbenzotriazole, silver salts of halogen-substituted benzotriazole such as silver 5-chlorobenzotriazole, and US Pat. No. 4,220,709, silver salts of 1,2,4-triazole or 1-H-tetrazole, and silver salts of imidazole and imidazole derivatives. For example, U.S. Pat.
Various silver acetylide compounds as described in 1,361 and 4,775,613 can also be used.

The shape of the organic silver salt which can be used in the present invention is not particularly limited, but a needle crystal having a short axis and a long axis is preferable. In the present invention, the minor axis is 0.01 μm or more.
20 μm or less, major axis 0.10 μm or more and 5.0 μm or less, minor axis 0.01 μm or more and 0.15 μm or less, major axis 0.10 μm or more
It is more preferably 4.0 μm or less. The particle size distribution of the organic silver salt is preferably monodispersed. Monodisperse and the minor axis, the percentage of the value obtained by dividing the standard deviation of the length of each major axis by each minor axis, major axis is preferably 100% or less, more preferably
It is at most 80%, more preferably at most 50%. The shape of the organic silver salt can be measured from a transmission electron microscope image of the organic silver salt dispersion. As another method of measuring monodispersity, there is a method of obtaining a standard deviation of a volume-weighted average diameter of an organic silver salt, and a percentage (coefficient of variation) of a value divided by a volume-weighted average diameter is preferably 100% or less. It is preferably at most 80%, more preferably at most 50%. As a measuring method, for example, the organic silver salt dispersed in a liquid is irradiated with laser light, and the particle size (volume weighted average diameter) obtained by obtaining an autocorrelation function with respect to a time change of the fluctuation of the scattered light is obtained. Can be.

The organic silver salt that can be used in the present invention includes:
Preferably, desalting can be performed. The method for desalting is not particularly limited, and a known method can be used. However, a known filtration method such as centrifugal filtration, suction filtration, ultrafiltration, or floc-forming water washing by a coagulation method can be preferably used.

For the purpose of obtaining fine particles having a small particle size and no aggregation, a method of preparing a solid fine particle dispersion using a dispersant is used for the organic silver salt which can be used in the present invention. The method of dispersing the organic silver salt into solid fine particles can be performed by a known method for making fine particles in the presence of a dispersing aid (for example, a ball mill, a vibration ball mill, a planetary ball mill, a sand mill, a colloid mill, a jet mill, a roller mill, a microfluidizer, It can be mechanically dispersed using a nanomizer, a Gaurin homogenizer), and a microfluidizer, a Nanomizer, and a Gaurin homogenizer are preferably used.

When the organic silver salt is formed into solid fine particles using a dispersant, for example, polyacrylic acid, a copolymer of acrylic acid, a maleic acid copolymer, a maleic acid monoester copolymer, and acryloylmethyl Synthetic anionic polymers such as propanesulfonic acid copolymers, semi-synthetic anionic polymers such as carboxymethyl starch and carboxymethyl cellulose, anionic polymers such as alginic acid and pectic acid, and JP-A-52-92716, WO88 / 04794, etc. Anionic surfactant described, the compound described in Japanese Patent Application No. 7-350753, or known anionic, nonionic,
Cationic surfactants and other known polymers such as polyvinyl alcohol, polyvinylpyrrolidone, carboxymethylcellulose, hydroxypropylcellulose, and hydroxypropylmethylcellulose, or naturally occurring polymer compounds such as gelatin can be appropriately selected and used. .

It is a common method to mix a dispersion aid with an organic silver salt powder or an organic silver salt in a wet cake state before dispersion, and to send it as a slurry to a dispersing machine. Heat treatment or treatment with a solvent may be performed in the combined state to obtain an organic silver salt powder or a wet cake. The pH may be controlled by a suitable pH adjuster before, during or after dispersion.

In addition to mechanical dispersion, the particles may be coarsely dispersed in a solvent by controlling the pH, and then finely divided by changing the pH in the presence of a dispersing agent. At this time, an organic solvent may be used as a solvent used for the coarse dispersion, and the organic solvent is usually removed after the completion of the fine particle formation.

The prepared dispersion is stored with stirring for the purpose of suppressing sedimentation of fine particles during storage, or stored in a highly viscous state (for example, in a jelly state using gelatin) by a hydrophilic colloid. You can also do.
Further, a preservative can be added for the purpose of preventing the propagation of various bacteria during storage.

The organic silver salt of the present invention can be used in a desired amount, preferably from 0.1 to 5 g / m ² as silver amount, more preferably from 1 to 3 g / m ^2.

In the present invention, in combination with the organic silver salt,
It is preferable to use a reducing agent for the organic silver salt. The reducing agent for the organic silver salt may be any substance that reduces silver ions to metallic silver, preferably an organic substance. Conventional photographic developers such as phenidone, hydroquinone and catechol are useful, but hindered phenol reducing agents are preferred. The reducing agent is preferably contained in an amount of 5 to 50% by mole, based on 1 mole of silver on the surface having the image forming layer, and 10 to 40% by mole.
More preferably, it is contained in mole%. Further, the reducing agent may be a so-called precursor which is derivatized so as to have a function effectively only during development.

In a photothermographic material utilizing an organic silver salt, a wide range of reducing agents are disclosed in JP-A-46-6074 and JP-A-47-1238.
No. 47-33621, No. 49-46427, No. 49-115540, No.
50-14334, 50-36110, 50-147711, 51-326
No. 32, No. 51-1023721, No. 51-32324, No. 51-51933,
52-84727, 55-108654, 56-146133, 57
-82828, 57-82829, JP-A-6-3793, U.S. Pat.
667,9586, 3,679,426, 3,751,252, 3,75
No. 1,255, No. 3,761,270, No. 3,782,949, No. 3,839,
No. 048, 3,928,686, 5,464,738, German patent 23
No. 21328 and European Patent No. 692732. For example, amide oximes such as phenylamidooxime, 2-thienylamidooxime and p-phenoxyphenylamidooxime; azines such as 4-hydroxy-3,5-dimethoxybenzaldehydeazine; 2,2-bis (hydroxymethyl) propionyl- a combination of an aliphatic carboxylic acid arylhydrazide such as a combination of β-phenylhydrazine and ascorbic acid and ascorbic acid; a combination of polyhydroxybenzene and hydroxylamine, reductone and / or hydrazine (for example, hydroquinone and bis (ethoxyethyl) ) Hydroxylamine, piperidinohexose reductone or formyl-4
A combination of azine and sulfonamidophenol (eg, phenothiazine and 2,6-dichloro-); hydroxamic acids such as phenylhydroxamic acid, p-hydroxyphenylhydroxamic acid and β-alinine hydroxamic acid; 4-benzenesulfonamidophenol); ethyl-α-cyano-2-
Α-cyanophenylacetic acid derivatives such as methylphenyl acetate, ethyl-α-cyanophenyl acetate; 2,
2-dihydroxy-1,1-binaphthyl, 6,6-dibromo-2,2-
Bis-β- as exemplified by dihydroxy-1,1-binaphthyl and bis (2-hydroxy-1-naphthyl) methane
Naphthol; a combination of bis-β-naphthol and a 1,3-dihydroxybenzene derivative (such as 2,4-dihydroxybenzophenone or 2,4-dihydroxyacetophenone); 3-methyl-1-phenyl-5-pyrazolone, Five-
Pyrazolones; reductones as exemplified by dimethylaminohexose reductone, anhydrodihydroaminohexose reductone and anhydrodihydropiperidone hexose reductone; 2,6-dichloro-4-benzenesulfonamidophenol and p- Sulfonamidophenol reducing agents such as benzenesulfonamidophenol; 2-phenylindan-1,3-dione and the like; chromanes such as 2,2-dimethyl-7-t-butyl-6-hydroxychroman; 2,6-dimethoxy- 1,4-dihydropyridines such as 3,5-dicarbethoxy-1,4-dihydropyridine; bisphenols (eg, bis (2-hydroxy-3-t-butyl-5-methylphenyl) methane, 2,2-bis ( 4-hydroxy-3-methylphenyl) propane, 4,4-ethylidene-bis (2-t-
Butyl-6-methylphenol), 1,1, -bis (2-hydroxy-3,5-dimethylphenyl) -3,5,5-trimethylhexane and 2,2-bis (3,5-dimethyl-4- Hydroxyphenyl) propane, etc.); ascorbic acid derivatives (eg,
And aldehydes and ketones such as benzyl and biacetyl; 3-pyrazolidone and certain indan-1,3-diones; chromanol (such as tocopherol). Particularly preferred reducing agents are bisphenol and chromanol.

The reducing agent of the present invention may be added by any method such as a solution, a powder, and a solid fine particle dispersion. The dispersion of the solid fine particles is carried out by a known fine means (for example, a ball mill, a vibrating ball mill, a sand mill, a colloid mill, a jet mill, a roller mill, a microfluidizer, a nanomizer, a Gaulin homogenizer, etc.). When dispersing the solid fine particles, a dispersing aid may be used.

At least one of the image forming layers of the present invention contains a polymer latex described below. Or later,
This image forming layer is referred to as “the image forming layer of the invention”. The polymer latex preferably contains at least 50% by weight of the total binder. The "polymer latex" referred to in the present invention is a water-insoluble hydrophobic polymer dispersed as fine particles in a water-soluble dispersion medium. The dispersion state is such that the polymer is emulsified in a dispersion medium, emulsion-polymerized, micelle-dispersed, or partially dispersed in polymer molecules and molecular chains themselves are molecularly dispersed. Any of them may be used. As for the polymer latex of the present invention, "Synthetic resin emulsion (Taira Okuda,
"Edited by Hiroshi Inagaki, published by the Society of Polymer Publishing (1978)", "Applications of Synthetic Latex (Takaaki Sugimura, Yasuo Kataoka, Soichi Suzuki, Keiji Kasahara, Published by the Society of Polymer Publishing (1993))", "Chemistry of Synthetic Latex" (Souichi Muroi, published by Kobunshi Kankokai (1970)). The average particle size of the dispersed particles is 1 to 50,000n
m, more preferably in the range of about 5 to 1000 nm.
There is no particular limitation on the particle size distribution of the dispersed particles, and those having a wide particle size distribution or those having a monodispersed particle size distribution may be used.

As the polymer latex of the present invention, other than a polymer latex having a normal uniform structure, a so-called core / polymer latex may be used.
Shell type latex may be used. In this case, it may be preferable to change the glass transition temperature of the core and the shell. The minimum film formation temperature (MFT) of the polymer latex of the present invention is -30 ° C.
To 90 ° C, more preferably about 0 ° C to 70 ° C. A film-forming auxiliary may be added to control the minimum film-forming temperature. The film-forming aid is also called a plasticizer and is an organic compound (usually an organic solvent) that lowers the minimum film-forming temperature of the polymer latex. )"It is described in.

Examples of the polymer used in the polymer latex of the present invention include acrylic resins, vinyl acetate resins, polyester resins, polyurethane resins, rubber resins, vinyl chloride resins, vinylidene chloride resins, polyolefin resins, and copolymers thereof. There is. The polymer may be a linear polymer, a branched polymer, or a crosslinked polymer. The polymer may be a so-called homopolymer in which a single monomer is polymerized, or a copolymer in which two or more monomers are polymerized. In the case of a copolymer, it may be a random copolymer or a block copolymer. The molecular weight of the polymer is preferably in the range of 5000 to 100000, more preferably about 10,000 to 100,000 in terms of number average molecular weight. If the molecular weight is too small, the mechanical strength of the image forming layer is insufficient, and if it is too large, the film-forming properties are poor, which is not preferable.

The polymer of the polymer latex used in the present invention has an equilibrium water content at 25 ° C. and 60% RH of 0.01 wt% or more and 2 watts.
t% or less, more preferably 0.01 wt% or more and 1 wt% or less. For the definition and measurement method of the equilibrium water content, for example, “Polymer Engineering Course 14, Polymer Material Testing Method (edited by the Society of Polymer Science, Jinjinshokan)” can be referred to.

Specific examples of the polymer latex used as a binder in the image forming layer of the photothermographic material of the present invention include methyl methacrylate / ethyl acrylate / methacrylic acid copolymer latex, methyl methacrylate / 2 ethylhexyl acrylate / styrene /
Latex of acrylic acid copolymer, latex of styrene / butadiene / acrylic acid copolymer, styrene /
Latex of butadiene / divinylbenzene / methacrylic acid copolymer, methyl methacrylate / vinyl chloride /
Latex of acrylic acid copolymer, vinylidene chloride /
Latex of ethyl acrylate / acrylonitrile / methacrylic acid copolymer and the like. Such polymers are also commercially available, and the following polymers can be used. Examples of acrylic resins include polyester resins such as Sebian A-4635,46583,4601 (manufactured by Daicel Chemical Industries, Ltd.) and Nipol Lx811,814,821,820,857 (manufactured by Zeon Corporation). HYDRAN AP1 is a polyurethane resin such as FINETEX ES650, 611, 675, 850 (all manufactured by Dainippon Ink and Chemicals, Inc.), WD-size, WMS (all manufactured by Eastman Chemical)
Rubber-based resins such as 0, 20, 30, 40 (all manufactured by Dainippon Ink and Chemicals, Inc.)
H, 7132C (from Dainippon Ink and Chemicals, Inc.), Nipol Lx
416, 410, 438C, 2507, (Nippon Zeon Co., Ltd.)
G351 and G576 (made by Nippon Zeon Co., Ltd.) as vinyl chloride resins, and L50 as vinylidene chloride resin
2. Examples of olefin resins include L-513 (all manufactured by Asahi Kasei Kogyo Co., Ltd.) and Chemipearl S120 and SA100 (all manufactured by Mitsui Petrochemical Co., Ltd.). These polymers may be used alone or as a blend of two or more as necessary. The polymer latex preferably contains a carboxylic acid component such as an acrylate or methacrylate component in an amount of about 0.1 to 10% by weight.

The image forming layer of the present invention comprises 50 wt.
% Or more is preferably the polymer latex, and more preferably 70 wt% or more is the polymer latex. A hydrophilic polymer such as gelatin, polyvinyl alcohol, methylcellulose, hydroxypropylcellulose, carboxymethylcellulose, or hydroxypropylmethylcellulose may be added to the image forming layer of the present invention, if necessary, in a range of 50% by weight or less of the total binder. The amount of the hydrophilic polymer to be added is preferably 30% by weight or less of the total binder in the image forming layer.

The image forming layer of the present invention is preferably prepared by applying an aqueous coating solution and then drying it. However, the term "aqueous" as used herein means that 50% by weight or more of the solvent (dispersion medium) of the coating liquid is water, and preferably 65% by weight or more of the solvent is water. As components other than water of the coating solution, water-miscible organic solvents such as methyl alcohol, ethyl alcohol, isopropyl alcohol, methyl cellosolve, ethyl cellosolve, dimethylformamide, and ethyl acetate can be used. Specific examples of the solvent composition include the following. Water / methanol = 90/10, water / methanol = 70 /
30, water / ethanol = 90/10, water / isopropanol = 9
0/10, water / dimethylformamide = 95/5, water / methanol / dimethylformamide = 80/15/5, water / methanol / dimethylformamide = 90/5/5. (However, numbers represent wt%.)

The image forming layer of the present invention has a total binder amount of 0.1.
² ~30g / m 2, more preferably in the range of 1 to 15 g / m ^2. In the image forming layer of the present invention, a crosslinking agent for crosslinking,
A surfactant or the like for improving coatability may be added.

In the present invention, the organic silver salt-containing fluid or
The thermal image forming layer coating solution is a so-called thixotropic fluid.
Preferably, there is. Thixotropy is the shear rate
It refers to the property of decreasing viscosity with increase. The viscosity of the present invention
Any instrument can be used for measurement, but rheometry
XS Far East Co., Ltd. RFS Fluid Spect
It is preferably used at 25 ° C. Departure
Organic silver salt containing fluid or thermal image forming layer coating in light
The liquid has a shear rate of 0.1S ^-1The viscosity at 400 mPas or more is 100,
000mPas or less, more preferably 500mPas
s or more and 20,000 mPa · s or less. Also, the shear rate 1000
S^-1In the range of 1 mPa · s to 200 mPa · s
And more preferably 5 mPas or more and 80 mPas or less.
You.

Various systems expressing thixotropy are known, and are described in “Lecture / Rheology”, edited by Polymer Publishing Association, Muroi,
It is described in Morino co-authored "Polymer Latex" (published by the Society of Polymer Publishing). In order for a fluid to exhibit thixotropic properties, it is necessary to contain a large amount of solid fine particles.
In order to enhance the thixotropic property, it is effective to include a thickened linear polymer, to increase the aspect ratio of the contained solid fine particles in an anisotropic shape, to increase the alkali thickening, and to use a surfactant.

When the present invention is used as a light-sensitive material, a light-sensitive silver halide is added. The silver halide may be added at any time during the preparation of the coating solution, but preferably immediately before coating.
The method of forming photosensitive silver halide in the present invention is well known in the art, for example, Research Disclosure No. 17029, June 1978, and U.S. Pat.
The method described in No. 458 can be used. Specific methods that can be used in the present invention include a method of converting a part of the silver of the organic silver salt to a photosensitive silver halide by adding a halogen-containing compound to the prepared organic silver salt, gelatin. Alternatively, a method of preparing a photosensitive silver halide grain by adding a silver supply compound and a halogen supply compound to another polymer solution and mixing the silver halide compound with an organic silver salt can be used. In the present invention, the latter method can be preferably used. The grain size of the photosensitive silver halide is preferably small for the purpose of suppressing white turbidity after image formation, specifically, 0.20 μm or less,
More preferably, it is 0.01 μm or more and 0.15 μm or less, and still more preferably 0.02 μm or more and 0.12 μm or less. Here, the grain size means the length of the edge of the silver halide grain when the silver halide grain is a cubic or octahedral so-called normal crystal. In the case where the silver halide grains are tabular grains, the diameter refers to a diameter when converted into a circular image having the same area as the projected area of the main surface. In the case of other than normal crystals, for example, in the case of spherical grains, rod-shaped grains, etc., it refers to the diameter of a sphere equivalent to the volume of silver halide grains.

The shape of the silver halide grains is cubic,
Octahedral, tabular particles, spherical particles, rod-like particles, potato-like particles and the like can be mentioned. In the present invention, cubic particles and tabular particles are particularly preferable. When tabular silver halide grains are used, the average aspect ratio is preferably from 100: 1 to 2: 1, more preferably from 50: 1 to 3: 1. Further, grains having rounded corners of silver halide grains can also be preferably used. The surface index (mirror index) of the outer surface of the photosensitive silver halide grains is not particularly limited, but the ratio of the [100] plane, which has high spectral sensitization efficiency when a spectral sensitizing dye is adsorbed, is high. preferable. The ratio is preferably at least 50%, more preferably at least 65%, even more preferably at least 80%. The ratio of the Miller index (100) plane is determined by T. Tani; J. Imaging Sci., 29, which utilizes the dependence of the adsorption of the sensitizing dye on the (111) plane and the (100) plane.
165 (1985).
The halogen composition of the photosensitive silver halide is not particularly limited, and may be any of silver chloride, silver chlorobromide, silver bromide, silver iodobromide, silver iodochlorobromide, and silver iodide. In the present invention, silver bromide or silver iodobromide can be preferably used. Particularly preferred is silver iodobromide, and the silver iodide content is preferably from 0.1 mol% to 40 mol%,
The content is more preferably from 0.1 mol% to 20 mol%. The distribution of the halogen composition in the grains may be uniform, the halogen composition may be changed stepwise, or may be changed continuously, but as a preferable example, the silver iodide content inside the grains is High silver iodobromide grains can be used. Preferably, silver halide grains having a core / shell structure can be used. The structure is preferably a two- to five-fold structure, more preferably a two to four-fold structure.
Heavy core / shell particles can be used.

The photosensitive silver halide grains of the present invention preferably contain at least one complex of a metal selected from rhodium, rhenium, ruthenium, osmium, iridium, cobalt, mercury or iron. One kind of these metal complexes may be used, or two or more kinds of complexes of the same metal and different metals may be used in combination. The preferable content is in the range of 1 nmol to 10 mmol, and more preferably in the range of 10 nmol to 100 μmol per 1 mol of silver. As a specific structure of the metal complex, a metal complex having a structure described in JP-A-7-225449 or the like can be used. As the compound of cobalt and iron, a hexacyano metal complex can be preferably used. Specific examples include ferricyanate ion, ferrocyanate ion, hexacyanocobaltate ion, and the like, but are not limited thereto. The phase containing the metal complex in the silver halide may be uniform, may be contained at a high concentration in the core portion, or may be contained at a high concentration in the shell portion, and there is no particular limitation.

The photosensitive silver halide grains can be desalted by washing with a method known in the art such as a noodle method or a flocculation method, but may or may not be desalted in the present invention. .

The photosensitive silver halide grains in the present invention are preferably chemically sensitized. As a preferred chemical sensitization method, a sulfur sensitization method, a selenium sensitization method, and a tellurium sensitization method are well known in the art. Further, a noble metal sensitization method or a reduction sensitization method of a gold compound, platinum, palladium, an iridium compound or the like can be used. As the compound preferably used in the sulfur sensitization method, the selenium sensitization method, and the tellurium sensitization method, known compounds can be used, and the compounds described in JP-A-7-128768 can be used. Examples of tellurium sensitizers include diacyl tellurides, bis (oxycarbonyl) tellurides,
Bis (carbamoyl) tellurides, diacyltellurides, bis (oxycarbonyl) ditellurides, bis (carbamoyl) ditellurides, compounds having a P = Te bond,
Tellurocarboxylates, Te-organyltellurocarboxylates, di (poly) tellurides, tellurides,
Tellurols, telluroacetals, tellursulfonates, compounds having a P-Te bond, Te-containing heterocycles, tellurocarbonyl compounds, inorganic tellurium compounds, colloidal tellurium, and the like can be used. Compounds preferably used in the noble metal sensitization method include, for example, chloroauric acid, potassium chloroaurate, potassium aurithiocyanate,
Gold sulfide, gold selenide, or US Patent 2,448,060
And the compounds described in British Patent No. 618,061 can be preferably used. Specific compounds of the reduction sensitization method include, as well as ascorbic acid, thiourea dioxide, for example, stannous chloride, aminoiminomethanesulfinic acid, hydrazine derivatives, borane compounds, silane compounds,
A polyamine compound or the like can be used. Reduction sensitization can be achieved by ripening the emulsion while maintaining the pH of the emulsion at 7 or more or the pAg at 8.3 or less. Further, reduction sensitization can be achieved by introducing a single addition portion of silver ion during grain formation.

The amount of the photosensitive silver halide used in the present invention is preferably 0.01 mol to 0.5 mol, more preferably 0.02 mol to 0.3 mol, and more preferably 0.03 mol to 1 mol of the organic silver salt. It is particularly preferably at least 0.25 mol and not more than 0.25 mol. Regarding the mixing method and the mixing conditions of the separately prepared photosensitive silver halide and organic silver salt, the prepared silver halide particles and organic silver salt are mixed with a high-speed stirrer, ball mill, sand mill, colloid mill, vibration mill, homogenizer, etc. There is a method of mixing, or a method of preparing an organic silver salt by mixing photosensitive silver halide prepared at any timing during the preparation of the organic silver salt,
There is no particular limitation as long as the effects of the present invention are sufficiently exhibited.

As the silver halide preparation method of the present invention, a so-called halation method in which a part of silver of an organic silver salt is halogenated with an organic or inorganic halide is also preferably used. The organic halide used here may be any compound as long as it is a compound that reacts with an organic silver salt to form a silver halide. Tetrabutylammonium bromide), an association of a quaternary nitrogen halide and a halogen molecule (pyridinium perbromide), and the like. As the inorganic halogen compound, any compound may be used as long as it reacts with an organic silver salt to generate a silver halide. ), Alkaline earth metal halides (such as calcium bromide and magnesium chloride), transition metal halides (such as ferric chloride and cupric bromide), and metal complexes having a halogen ligand (sodium iridium bromide) , Ammonium rhodate, etc.), and halogen molecules (bromine, chlorine, iodine). Further, a desired organic / inorganic halide may be used in combination. In the present invention, the amount of the halide to be added is preferably from 1 mmol to 500 mmol, more preferably from 10 mmol to 250 mmol, as a halogen atom per 1 mol of the organic silver salt.

The photosensitive silver halide in the present invention may be spectrally sensitized with a sensitizing dye. As the sensitizing dye of the present invention, any dye can be used as long as it can spectrally sensitize the silver halide grains in a desired wavelength region when adsorbed on the silver halide grains. As sensitizing dyes, cyanine dyes, merocyanine dyes, complex cyanine dyes, complex merocyanine dyes, holo-holer cyanine dyes,
Styryl dye, hemicyanine dye, oxonol dye,
Hemioxonol dyes and the like can be used. Useful sensitizing dyes for use in the present invention include, for example, RESEARCH DISCLOS
URE Item17643IV-A (p.23, December 1978), Item1831
It is described in the literature cited or cited in section X (p. 437, August 1979). In particular, a sensitizing dye having a spectral sensitivity suitable for the spectral characteristics of the light source of various laser imagers, scanners, imagesetters and plate making cameras can be advantageously selected.

As an example of spectral sensitization to red light, He-Ne
For so-called red light sources such as lasers, red semiconductor lasers and LEDs, compounds of I-1 to I-38 described in JP-A-54-18726, and compounds of I-1 described in JP-A-6-75322 are disclosed. I
-35 and the compounds I-1 to I-34 described in JP-A-7-287338, and the dye 1 described in JP-B-55-39818.
20, compounds of I-1 to I-37 described in JP-A-62-284343 and compounds of I-1 to I-34 described in JP-A-7-287338 are advantageously selected.

For semiconductor laser light sources in the wavelength range of 750 to 1400 nm, various known dyes, including cyanine, merocyanine, styryl, hemicyanine, oxonol, hemioxonol and xanthene dyes, advantageously spectrally sensitize. Can be done. Useful cyanine dyes are, for example, cyanine dyes having basic nuclei such as thiazoline nuclei, oxazoline nuclei, pyrroline nuclei, pyridine nuclei, oxazole nuclei, thiazole nuclei, selenazole nuclei and imidazole nuclei. Preferred useful merocyanine dyes include, in addition to the above basic nuclei, acidic nuclei such as thiohydantoin nucleus, rhodanine nucleus, oxazolidinedione nucleus, thiazolinedione nucleus, barbituric acid nucleus, thiazolinone nucleus, malononitrile nucleus and pyrazolone nucleus. Including. Among the above cyanine and merocyanine dyes, those having an imino group or a carboxyl group are particularly effective. For example, U.S. Pat.
3,719,495 and 3,877,943, UK Patent 1,466,201
No. 1,469,117, No. 1,422,057, Tokuhei 3-10391
No., 6-52387, JP-A-5-341432, 6-94781,
It may be appropriately selected from known dyes as described in JP-A-6-301141.

Particularly preferred as the structure of the dye used in the present invention is a cyanine dye having a thioether bond-containing substituent (for example, JP-A Nos. 62-58239 and 3-1386).
No.38, No.3-138642, No.4-255840, No.5-72659, No.
5-72661, 6-222491, 2-230506, 6-258757
No., 6-317868, 6-324425, Tokuyohei 7-500926,
Dyes described in U.S. Pat. No. 5,541,054), dyes having a carboxylic acid group (for example, JP-A-3-163440, 6-3011
No. 41, U.S. Pat. No. 5,441,899), merocyanine dyes, polynuclear merocyanine dyes and polynuclear cyanine dyes (JP-A-47-6329, JP-A-49-105524, JP-A-51-127719).
No. 52-80829, No. 54-61517, No. 59-214846, No.
60-6750, 63-159841, JP-A-6-35109, 6-
No.59381, No.7-146537, No.7-146537, Tokiohei 55-501
No. 11, British Patent 1,467,638 and U.S. Pat. No. 5,281,515). Further, as the dye forming a J-band, the dyes described in Example 5 of U.S. Pat. Nos. 5,510,236 and 3,871,887, JP-A-2-96131, JP-A-59-487
No. 53 is disclosed and can be preferably used in the present invention.

These sensitizing dyes may be used alone.
Two or more kinds may be used in combination. Combinations of sensitizing dyes are often used, especially for supersensitization. Along with the sensitizing dye, the emulsion may contain a dye which does not itself have a spectral sensitizing effect or a substance which does not substantially absorb visible light and exhibits supersensitization. Useful sensitizing dyes, combinations of dyes exhibiting supersensitization and substances exhibiting supersensitization are Re.
search Disclosure Volume 176 Volume 17643 (Issued December 1978) No. 23
Paragraph J on page IV, or JP-B-49-25500, 43-4933
And JP-A-59-19032 and JP-A-59-192242.

The sensitizing dyes used in the present invention may be used in combination of two or more. The sensitizing dyes may be added to the silver halide emulsion by dispersing them directly in the emulsion or by adding water, methanol, ethanol, propanol, acetone, methylcellosolve, 2,2,3,3 -Tetrafluoropropanol, 2,2,2-trifluoroethanol, 3-
A solvent such as methoxy-1-propanol, 3-methoxy-1-butanol, 1-methoxy-2-propanol, N, N-dimethylformamide or the like may be dissolved alone or in a mixed solvent and added to the emulsion. Further, as disclosed in U.S. Pat. No. 3,469,987, a dye is dissolved in a volatile organic solvent, and the solution is dispersed in water or a hydrophilic colloid.
A method of adding this dispersion to an emulsion, JP-B-44-23389
As disclosed in Nos. 44-27555 and 57-22091, a dye is dissolved in an acid and the solution is added to the emulsion, or an acid or base is allowed to coexist to form an aqueous solution in the emulsion. A method of adding an aqueous solution or a colloidal dispersion in the presence of a surfactant as disclosed in U.S. Pat. Nos. 3,822,135 and 4,006,025, and the like; JP-A-51-733 and JP-A-58-105141, a method in which a dye is directly dispersed in a hydrophilic colloid and the dispersion is added to an emulsion.
As disclosed in Japanese Patent No. 4624, a method of dissolving a dye using a compound that causes a red shift and adding the solution to an emulsion can also be used. Also, ultrasonic waves can be used for the solution.

The sensitizing dye used in the present invention may be added to the silver halide emulsion of the present invention at any stage of the emulsion preparation which has been found to be useful. For example, U.S. Pat.Nos. 2,735,766 and 3,628,960
No. 4,183,756, No. 4,225,666, JP-A-58-18414
As disclosed in the specifications of JP-A Nos. 2 and 60-196749, chemical ripening is carried out during the step of forming silver halide grains and / or before desalting, during and / or after desalting. Before the start of the emulsion, as disclosed in the specification of JP-A-58-113920, etc., immediately before or during the process of chemical ripening, after the chemical ripening, and before the application of the emulsion before the coating. If so, it may be added at any time in the process. Further, as disclosed in the specification of U.S. Pat. No. 4,225,666, Japanese Patent Application Laid-Open No. 58-7629, etc., the same compound may be used alone or in combination with a compound having a heterogeneous structure, for example, during the particle forming step. The compound may be divided and added during the ripening step or after the completion of the chemical ripening, or may be added separately before or during the chemical ripening or after the completion of the chemical ripening. May be added.

The amount of the sensitizing dye used in the present invention may be a desired amount according to the performance such as sensitivity and fog.
The amount is preferably from 10 ^-6 to 1 mol, more preferably from 10 ^-4 to 10 ^-1 mol, per mol of silver halide in the photosensitive layer.

In the present invention, the photosensitive silver halide may be added to the coating solution for the image forming layer before, after or simultaneously with the mixing of the polymer latex, but preferably at the same time or after the mixing of the polymer latex. And
After mixing of the polymer latex is particularly preferred.

When an additive known as a "toning agent" for improving an image is contained, the optical density may be increased. The toning agent may also be advantageous in forming a black silver image. The color-toning agent is preferably contained in an amount of 0.1 to 50% mol, more preferably 0.5 to 20% mol, per mol of silver on the surface having the image forming layer. Further, the toning agent may be a so-called precursor which is derivatized so as to have a function effectively only during development.

In a photothermographic material utilizing an organic silver salt, a wide range of color toning agents are disclosed in JP-A-46-6077 and JP-A-47-10282.
Nos. 49-5019, 49-5020, 49-91215, 49
-91215, 50-5024, 50-32927, 50-67132
No. 50-67641, No. 50-114217, No. 51-3223, No. 5
1-27923, 52-14788, 52-99813, 53-1020
No. 53-76020, No. 54-156524, No. 54-156525,
No. 61-183642, JP-A-4-56848, JP-B-49-10727
No. 54-20333, U.S. Pat.Nos. 3,080,254, 3,446,64
No. 8, 3,782,941, 4,123,282, 4,510,236
And British Patent 1380795 and Belgian Patent 841910. Examples of toning agents are phthalimide and N-
Hydroxyphthalimide; succinimide, pyrazoline
And cyclic imides such as quinazolinone, 3-phenyl-2-pyrazolin-5-one, 1-phenylurazole, quinazoline and 2,4-thiazolidinedione; naphthalimides (eg, N-hydroxy-1 , 8-naphthalimide); cobalt complex (eg, cobalt hexamine trifluoroacetate); 3-mercapto-1,2,4-triazole, 2,4-dimercaptopyrimidine, 3-mercapto-4,5
Mercaptans exemplified by -diphenyl-1,2,4-triazole and 2,5-dimercapto-1,3,4-thiadiazole;
N- (aminomethyl) aryldicarboximides (eg, (N, N-dimethylaminomethyl) phthalimide and N, N- (dimethylaminomethyl) -naphthalene-2,3-dicarboximide); and blocked pyrazoles , Isothiuronium derivatives and certain photobleaching agents such as N, N'-hexamethylenebis (1-carbamoyl-3,5-
Dimethylpyrazole), 1,8- (3,6-diazaoctane) bis (isothiuronium trifluoroacetate) and
2-tribromomethylsulfonyl)-(benzothiazole)); and 3-ethyl-5 (3-ethyl-2-benzothiazolinylidene) -1-methylethylidene-2-thio-2,4-oxazolidinedione; Phthalazinone, a phthalazinone derivative or metal salt, or 4- (1-naphthyl) phthalazinone,
Derivatives such as 6-chlorophthalazinone, 5,7-dimethoxyphthalazinone and 2,3-dihydro-1,4-phthalazinedione; phthalazinone and phthalic acid derivatives (for example, phthalic acid, 4-methylphthalic acid, Phthalazine, phthalazine derivatives or metal salts, or 4- (1-naphthyl) phthalazine, 6-chlorophthalazine, 5,7-dimethoxyphthalazine and 2,3- Derivatives such as dihydrophthalazine; phthalazine and phthalic acid derivatives (for example, phthalic acid,
Quinazolinedione, such as 4-methylphthalic acid, 4-nitrophthalic acid and tetrachlorophthalic anhydride;
Benzoxazine or naphthoxazine derivatives; rhodium complexes that function not only as color tone regulators but also in-situ as sources of halide ions for silver halide formation, such as ammonium hexachlororhodate (III), rhodium bromide, rhodium nitrate And potassium hexachlororhodate (III); inorganic peroxides and persulfates such as ammonium disulfide and hydrogen peroxide; 1,3-benzoxazine-2,4-dione, 8-methyl
-1,3-benzoxazine-2,4-dione and 6-nitro-
Benzoxazine-2,4-dione such as 1,3-benzoxazine-2,4-dione; pyrimidine and asymmetric-triazine (eg, 2,4-dihydroxypyrimidine, 2-hydroxy-4-aminopyrimidine and the like), Azauracil and tetraazapentalene derivatives (for example, 3,6-dimercapto-1,4-diphenyl-1H, 4H-2,3a, 5,6a-tetraazapentalene, and 1,4-di (o-chlorophenyl ) -3,6-dimercapto-1H, 4H-2,3a, 5,6a-tetraazapentalene).

The color-toning agent of the present invention may be added by any method such as a solution, a powder, and a dispersion of solid fine particles. The dispersion of the solid fine particles is carried out by a known means for making fine (for example, a ball mill, a vibration ball mill, a sand mill, a colloid mill, a jet mill, a roller mill, etc.). When dispersing the solid fine particles, a dispersing aid may be used.

The silver halide emulsion according to the present invention or /
And the organic silver salts can be further protected against the formation of additional fog by antifoggants, stabilizers and stabilizer precursors, and can be stabilized against reduced sensitivity during stock storage. Suitable antifoggants, stabilizers and stabilizer precursors that can be used alone or in combination are the thiazonium salts described in U.S. Pat.Nos. 2,131,038 and 2,694,716; U.S. Pat.Nos. 2,886,437 and 2,444,605. Azaindene, U.S. Pat.
No. 728,663, mercury salts described in U.S. Pat.
No. 405, the polyvalent metal salts described in U.S. Pat.
Palladium, platinum and gold salts described in U.S. Patent Nos. 4,108,665 and 4,442,20
Halogen-substituted organic compounds described in No. 2, U.S. Pat.
Nos. 8,557 and 4,137,079, 4,138,365 and 4,459,350, and the phosphorus compounds described in U.S. Pat. No. 4,411,985.

The antifoggant preferably used in the present invention is an organic halide, for example, as described in JP-A-50-119624.
No. 50-120328, No. 51-121332, No. 54-58022,
56-70543, 56-99335, 59-90842, 61-129
No. 642, No. 62-129845, JP-A-6-208191, No. 7-5621
No. 7-2781, No. 8-15809, U.S. Pat.
And compounds disclosed in JP-A Nos. 5369000/5464737.

The antifoggant of the present invention may be added by any method such as a solution, a powder, and a solid fine particle dispersion. The dispersion of the solid fine particles is carried out by a known means for making fine (for example, a ball mill, a vibration ball mill, a sand mill, a colloid mill, a jet mill, a roller mill, etc.). When dispersing the solid fine particles, a dispersing aid may be used.

Although not required to practice the present invention,
It may be advantageous to add a mercury (II) salt as an antifoggant to the emulsion layer. Preferred mercury (II) salts for this purpose are
Mercury acetate and mercury bromide. The addition amount of mercury used in the present invention is preferably 1 nmol to 1 mmol, more preferably 10 nmol to 100 μm per 1 mol of coated silver.
Range of moles.

The photothermographic material of the present invention may contain benzoic acids for the purpose of increasing the sensitivity and preventing fog. The benzoic acids of the present invention may be any benzoic acid derivative, but examples of preferred structures include those described in U.S. Pat.
No. 9, No. 4, 152, 160, Japanese Patent Application No. 8-151242, No. 8-151241
And the compounds described in JP-A-8-98051. The benzoic acids of the present invention may be added to any part of the light-sensitive material. However, the added layer is preferably added to the layer having the photosensitive layer, and more preferably added to the organic silver salt-containing layer. . The benzoic acid of the present invention may be added at any time during the preparation of the coating solution, and when it is added to the organic silver salt-containing layer, it may be added at any time from the preparation of the organic silver salt to the preparation of the coating solution. It is preferable after salt preparation and immediately before application. The benzoic acid of the present invention may be added by any method such as powder, solution, and fine particle dispersion. Further, it may be added as a solution mixed with other additives such as a sensitizing dye, a reducing agent and a color tone agent. The benzoic acid of the present invention may be added in any amount, but preferably 1 μmol or more and 2 mol or less, more preferably 1 mmol or more per 1 mol of silver.
0.5 mol or less is more preferred.

In the present invention, a mercapto compound, a disulfide compound, and a thione compound are contained to control development by suppressing or accelerating development, to improve spectral sensitization efficiency, and to improve storage stability before and after development. be able to. When using a mercapto compound in the present invention, any structure may be used, but Ar-SM, Ar-SSA
Those represented by r are preferred. In the formula, M is a hydrogen atom or an alkali metal atom, and Ar is an aromatic ring or a condensed aromatic ring group having one or more nitrogen, sulfur, oxygen, selenium or tellurium atoms. Preferred heteroaromatic rings are benzimidazole, naphthimidazole, benzothiazole, naphthothiazole, benzoxazole, naphthoxazole, benzoselenazole, benzotellurazole, imidazole, oxazole, pyrazole, triazole, thiadiazole, tetrazole, triazine, pyrimidine, pyridazine, pyrazine , Pyridine, purines, quinolines or quinazolinones. The heteroaromatic group includes, for example, halogen (eg, Br and Cl),
Hydroxy, amino, carboxy, alkyl (eg,
One or more carbon atoms, preferably having 1 to 4 carbon atoms) and alkoxy (for example, having one or more carbon atoms, preferably having 1 to 4 carbon atoms)
And a substituent selected from the group consisting of:
As mercapto-substituted heteroaromatic compounds, 2-mercaptobenzimidazole, 2-mercaptobenzoxazole, 2-mercaptobenzothiazole, 2-mercapto-5
-Methylbenzimidazole, 6-ethoxy-2-mercaptobenzothiazole, 2,2'-dithiobis-benzothiazole, 3-mercapto-1,2,4-triazole, 4,5-diphenyl-2-imidazolethiol, 2- Mercaptoimidazole, 1-ethyl-2-mercaptobenzimidazole, 2-
Mercaptoquinoline, 8-mercaptopurine, 2-mercapto-4 (3H) -quinazolinone, 7-trifluoromethyl-4-quinolinethiol, 2,3,5,6-tetrachloro-4-pyridinethiol, 4-amino- 6-hydroxy-2-mercaptopyrimidine monohydrate, 2-amino-5-mercapto-1,3,4-
Thiadiazole, 3-amino-5-mercapto-1,2,4-triazole, 4-hydrokilos-2-mercaptopyrimidine, 2-
Mercaptopyrimidine, 4,6-diamino-2-mercaptopyrimidine, 2-mercapto-4-methylpyrimidine hydrochloride, 3-mercapto-5-phenyl-1,2,4-triazole, 2-mercapto-4-phenyloxazole, etc. However, the present invention is not limited to these.

The addition amount of these mercapto compounds is preferably in the range of 0.001 to 1.0 mol per mol of silver in the emulsion layer, more preferably 0.01 to 1.0 mol per mol of silver.
The amount is 0.3 mol.

In the photosensitive layer according to the present invention, a polyhydric alcohol (for example, US Pat.
Glycerin and diols of the type described in U.S. Pat. No. 960,404), fatty acids or esters described in U.S. Pat. Nos. 2,588,765 and 3,121,060, and silicone resins described in British Patent No. 955,061.

In the present invention, a super-high contrast agent can be used for forming a super-high contrast image. For example, U.S. Patent No. 5,464,73
No. 8, No. 5,496,695, No. 6,512,411, No. 5,536,622
No., Patent Application No. 7-228627, No. 8-215822, No. 8-130842
Nos. 8-148113, 8-156378, 8-148111, 8-
The hydrazine derivative described in 148116, the compound having a quaternary nitrogen atom described in Japanese Patent Application No. 8-83566, and the acrylonitrile compound described in US Pat. No. 5,545,515 can be used. Specific examples of the compound include compounds 1 to 10 and 5,496,69 of the aforementioned U.S. Patent No. 5,464,738.
H-1 to H-28 of No. 5, I-1 to I-86 of Japanese Patent Application No. 8-215822,
H-1 to H-62 of 8-130842, 1-1 to 1-2 of 8-148113
1, 1 to 50 of 8-148111, 1 to 40 of 8-148116, 8
-83566, P-1 to P-26, and T-1 to T-18; and US Pat. No. 5,545,515, CN-1 to CN-13.

Further, the present invention provides a method for forming a super-high contrast image.
A high contrast accelerator can be used in combination with the above-mentioned super-high contrast agent. For example, amine compounds described in U.S. Pat.No. 5,545,505, specifically AM-1 to AM-5, and hydroxamic acids described in 5,545,507, specifically HA-1 to HA-11,
Acrylonitrile described in 5,545,507, specifically
CN-1 to CN-13, hydrazine compounds described in US Pat. No. 5,558,983, specifically CA-1 to CA-6, onium salts described in Japanese Patent Application No. 8-132836, specifically A -1 to A-42, B-1 to B-
27, C-1 to C-14 and the like can be used. These ultra-high contrast agents, and a method of synthesizing a high contrast enhancement agent, an addition method
The addition amount and the like can be determined as described in each of the cited patents.

The image forming material of the present invention may be provided with a surface protective layer for the purpose of preventing adhesion of the image forming layer. Although any polymer may be used as the binder for the surface protective layer of the present invention, it is preferable that the polymer having a carboxylic acid residue is contained in an amount of 100 mg / m ^{2 to} 5 g / m ² . Examples of the polymer having a carboxyl residue include natural polymers (such as gelatin and alginic acid), modified natural polymers (such as carboxymethylcellulose and phthalated gelatin), and synthetic polymers (polymethacrylate, polyacrylate, polyalkylmethacrylate / acrylate). Copolymer, polystyrene / polymethacrylate copolymer, etc.). The content of carboxy residues in the polymer is preferably from 10 mmol to 1.4 mol per 100 g of the polymer. Further, the carboxylic acid residue may form a salt with an alkali metal ion, an alkaline earth metal ion, an organic cation, or the like.

As the surface protective layer of the present invention, any anti-adhesion material may be used. Examples of anti-adhesion materials include wax, silica particles, styrene-containing elastomeric block copolymers (eg, styrene-butadiene-styrene, styrene-isoprene-styrene), cellulose acetate, cellulose acetate butyrate, cellulose propionate, and the like. And mixtures. Further, a crosslinking agent for crosslinking and a surfactant for improving coating properties may be added to the surface protective layer.

In the image forming layer or the protective layer of the image forming layer in the present invention, US Pat. Nos. 3,253,921 and 2,27
It can be used in photographic elements containing light absorbing materials and filter dyes as described in 4,782, 2,527,583 and 2,956,879. Also,
Dyes can be mordanted, for example, as described in U.S. Pat. No. 3,282,699. The amount of the filter dye used is preferably such that the absorbance at the exposure wavelength is 0.1 to 3, and 0.2 to 1.5.
Is particularly preferred. The image forming layer or emulsion layer of the present invention comprises a matting agent such as starch, titanium dioxide, zinc oxide, silica, beads of the type described in U.S. Pat. Nos. 2,992,101 and 2,701,245. It may contain polymer beads and the like. Also,
The matte degree of the emulsion surface may be any value as long as no star dust failure occurs, but the Beck smoothness is preferably from 200 seconds to 10,000 seconds, and particularly preferably from 300 seconds to 10,000 seconds.

The photothermographic emulsion of the present invention comprises one or more layers on a support. One layer construction must include optional additional materials such as organic silver salts, silver halides, developers and binders, and toning agents, coating aids and other auxiliaries. The two-layer construction is such that the first emulsion layer (usually the layer adjacent to the base) contains an organic silver salt and silver halide, and the second layer or both layers do not contain some other components. No. However, a two-layer construction comprising a single emulsion layer containing all components and a protective topcoat is also contemplated. The construction of a multicolor photothermographic material may include a combination of these two layers for each color, or may include all components in a single layer as described in U.S. Pat.No. 4,708,928. Is also good. In the case of a multi-dye, multi-color photosensitive heat-developable photographic material, each emulsion layer is generally prepared as described in U.S. Pat.No. 4,460,681.
The use of a functional or non-functional barrier layer between each photosensitive layer keeps it distinct from each other.

Various dyes and pigments can be used in the photosensitive layer of the present invention from the viewpoint of improving color tone and preventing irradiation. Dyes and pigments used in the photosensitive layer of the present invention may be any, for example, there are pigments and dyes described in the color index, specifically, pyrazoloazole dye, anthraquinone dye, azo dye, azomethine dye,
Oxonol dyes, carbocyanine dyes, styryl dyes, triphenylmethane dyes, indoaniline dyes, indophenol dyes, organic pigments including phthalocyanine, and inorganic pigments. Preferred dyes used in the present invention include anthraquinone dyes (for example, compounds 1 to 9 described in JP-A-5-341441, compounds 3-6 to 18 and 3-23 to 38 described in JP-A-5-165147), azomethine Dyes (such as compounds 17 to 47 described in JP-A-5-341441),
Indoaniline dyes (for example, compounds 11 to 19 described in JP-A-5-289227, compound 47 described in JP-A-5-341441,
And azo dyes (compounds 10 to 16 described in JP-A-5-341441). As a method for adding these dyes, any method such as a solution, an emulsion, a solid fine particle dispersion, and a state in which the dye is mordanted with a polymer mordant may be used. The amount of these compounds used is determined depending on the target absorption amount, but is generally 1 μm / m ^2.
It is preferable to use in the range of g or more and 1 g or less.

In the present invention, the antihalation layer can be provided on the side farther from the light source than the photosensitive layer. The antihalation layer preferably has a maximum absorption in a desired wavelength range of 0.3 or more and 2 or less, more preferably an absorption of an exposure wavelength of 0.5 or more and 2 or less, and an absorption in a visible region after processing of 0.001 or more. It is preferably less than 0.5, more preferably 0.001 or more and 0.3
It is preferable that the layer has an optical density of less than.

When an antihalation dye is used in the present invention, the dye has a desired absorption in the wavelength range, has a sufficiently low absorption in the visible region after treatment, and has a desirable absorbance spectrum shape of the antihalation layer. Any compound can be used as long as it is possible. For example, the following are disclosed, but the present invention is not limited thereto.
As a single dye, JP-A-59-56458, JP-A-2-216140
No. 7-13295, No. 7-11432, U.S. Patent 5,380,635
JP-A-2-68539, page 13, lower left column, line 1 to page 14, lower left column, line 9; JP-A-3-24539, page 14, lower left column, page 16, lower right column There are compounds, and as dyes that can be decolorized by treatment, JP-A-52-139136, JP-A-53-132334,
56-501480, 57-16060, 57-68831, 57-1
01835, 59-182436, JP-A-7-36145, 7-19
9409, JP-B-48-33692, JP-B50-16648, JP-B2-41
No. 734, U.S. Pat.Nos. 4,088,497, 4,283,487,
There are 548,896 and 5,187,049.

The photothermographic material of the present invention comprises:
Having a light-sensitive layer containing at least one silver halide emulsion on one side of the support and a back layer on the other side;
It is preferably a so-called one-sided photosensitive material.

In the present invention, a matting agent may be added to the single-sided photosensitive material in order to improve transportability. The matting agent is generally fine particles of an organic or inorganic compound insoluble in water. Any matting agent can be used, for example, U.S. Patent Nos. 1,939,213, 2,701,245, and 2,32
2,037, 3,262,782, 3,539,344, 3,767,
Organic matting agents described in each specification such as No. 448, 1,260,77
No. 2, 2,192,241, 3,257,206, 3,370,951
Nos. 3,523,022, 3,769,020, etc., and those well known in the art such as inorganic matting agents described in each specification can be used. For example, specifically, examples of organic compounds that can be used as a matting agent include, as examples of water-dispersible vinyl polymers, polymethyl acrylate, polymethyl methacrylate, polyacrylonitrile, acrylonitrile-α-methylstyrene copolymer, and polystyrene. ,
Styrene-divinylbenzene copolymer, polyvinyl acetate, polyethylene carbonate, polytetrafluoroethylene, etc., examples of cellulose derivatives such as methylcellulose, cellulose acetate, cellulose acetate propionate, etc., and starch derivatives such as carboxy starch and carboxynitrophenyl starch , Urea-formaldehyde-starch reactant, and the like, and gelatin hardened with a known hardener and hardened gelatin that has been coacervated and hardened into microcapsule hollow particles can be preferably used. As examples of the inorganic compound, silicon dioxide, titanium dioxide, magnesium dioxide, aluminum oxide, barium sulfate, calcium carbonate, silver chloride desensitized by a known method, silver bromide, glass, and diatomaceous earth can be preferably used. The above matting agents can be used by mixing different types of substances as necessary. The size and shape of the matting agent are not particularly limited, and those having an arbitrary particle size can be used. 0.1 μm to 3 μm
It is preferable to use one having a particle size of 0 μm. Further, the particle size distribution of the matting agent may be narrow or wide. On the other hand, since the matting agent greatly affects the haze and surface gloss of the light-sensitive material, the particle size, shape, and particle size distribution can be changed as necessary during the preparation of the matting agent or by mixing a plurality of matting agents. preferable.

In the present invention, the matte degree of the back layer is preferably such that the Bekk smoothness is 250 seconds or less and 10 seconds or more, and more preferably 180 seconds or less and 50 seconds or more. In the present invention, the matting agent is preferably contained in the layer functioning as the outermost surface layer or the outermost surface layer of the light-sensitive material, or in a layer close to the outer surface, and is contained in a layer acting as a so-called protective layer. Is preferred.

In the present invention, suitable binders for the back layer are transparent or translucent, generally colorless, and include natural polymer synthetic resins, polymers and copolymers, and other film-forming media such as: gelatin, gum arabic, and poly (vinyl). Alcohol), hydroxyethylcellulose, cellulose acetate, cellulose acetate butyrate, poly (vinylpyrrolidone), casein, starch, poly (acrylic acid), poly (methylmethacrylic acid), poly (vinyl chloride), poly (methacrylic acid), copoly (Styrene-maleic anhydride), copoly (styrene-acrylonitrile), copoly (styrene-butadiene), poly (vinyl acetal) s (eg, poly (vinyl formal) and poly (vinyl butyral)), poly (ester) s, Poly (C Tan), phenoxy resins, poly (vinylidene chloride), poly (epoxides),
Poly (carbonate) s, poly (vinyl acetate),
There are cellulose esters and poly (amides). The binder may be coated from water or an organic solvent or emulsion.

In the present invention, the back layer preferably has a maximum absorption in a desired wavelength range of 0.3 or more and 2 or less, more preferably an absorption of 0.5 or more and 2 or less, and an absorption in a visible region after the treatment. Is preferably 0.001 or more and less than 0.5, more preferably 0.001 or more
Preferably, the layer has an optical density of less than 0.3.
Examples of the antihalation dye used in the back layer are the same as those of the antihalation layer described above.

US Pat. Nos. 4,460,681 and 4,374,
The backside resistive heating layer (backside re
A sistive heating layer) can also be used in a photothermographic image system.

A hardener may be used for each layer such as the photosensitive layer, the protective layer and the back layer of the present invention. Examples of hardeners include T.
"THE THEORY OF THE PHOTOGRAPHIC PROCESS" by H. James
FOURTH EDITION (Macmillan Publishing Co., Inc.
Published in 1977) There are various methods described on pages 77 to 87, polyvalent metal ions described on page 78 of the same book, U.S. Patent 4,281,060
Polyisocyanates such as JP-A-6-208193, epoxy compounds such as U.S. Pat.
-89048 and the like are preferably used.

In the present invention, a surfactant may be used for the purpose of improving coating properties and charging. As the surfactant, any surfactant such as nonionic, anionic, cationic, and fluorine can be used as appropriate. Specifically,
No. 62-170950, U.S. Pat.No.5,380,644, etc.
No. 188135, U.S. Patent
No. 3,885,965, etc.
Examples thereof include polyalkylene oxides and anionic surfactants described in JP-A-6-301140.

Examples of the solvent used in the present invention include a new edition solvent pocket book (Ohm Co., 1994), but the present invention is not limited thereto. The solvent used in the present invention has a boiling point of 40 ° C or more and 180 ° C or more.
C. or lower is preferred. Examples of the solvent of the present invention include hexane, cyclohexane, toluene, methanol, ethanol, isopropanol, acetone, methyl ethyl ketone, ethyl acetate, 1,1,1-trichloroethane, tetrahydrofuran, triethylamine, thiophene, trifluoroethanol, perfluoropentane, xylene , N-
Butanol, phenol, methyl isobutyl ketone, cyclohexanone, butyl acetate, diethyl carbonate, chlorobenzene, dibutyl ether, anisole, ethylene glycol diethyl ether, N, N-dimethylformamide,
Examples include morpholine, propane sultone, perfluorotributylamine, water and the like.

The photographic emulsion for heat development in the present invention can be coated on various supports. Typical supports include polyester films, primed polyester films, poly (ethylene terephthalate) films, polyethylene naphthalate films, cellulose nitrate films, cellulose ester films, poly (vinyl acetal) films, polycarbonate films and related or resinous Including materials, as well as glass, paper, metal and the like. Flexible substrates, especially coated with baryta paper or partially acetylated α-olefin polymers, especially polymers of C 2-10 α-olefins such as polyethylene, polypropylene, ethylene-butene copolymer A paper support is typically used. The support may be transparent or opaque, but is preferably transparent.

The photothermographic material of the present invention may contain an antistatic or conductive layer such as a soluble salt (eg, chloride,
Nitrate, etc.), a vapor-deposited metal layer, a layer containing an ionic polymer as described in U.S. Pat. Good.

As a method for obtaining a color image using the heat-developable photosensitive material of the present invention, there is a method described in JP-A-7-13295, page 10, left column, line 43 to 11 left column, line 40. Examples of color dye image stabilizers include British Patent No. 1,326,889, U.S. Patent Nos. 3,432,300, 3,698,909, and 3,574,
Nos. 627, 3,573,050, 3,764,337 and 4,042,394.

In the heat-developable photographic material of the present invention, additional layers such as a dye-receiving layer for receiving a moving dye image, an opaque layer if reflective printing is desired, a protective topcoat layer and photothermographic techniques It may include a known primer layer and the like. The light-sensitive material of the present invention is preferably capable of forming an image with only one light-sensitive material, and it is preferable that a functional layer necessary for image formation such as an image receiving layer does not become another light-sensitive material.

The light-sensitive material of the present invention may be developed by any method, but is usually developed by raising the temperature of the light-sensitive material exposed imagewise. The preferred development temperature is 80 to
The temperature is 250 ° C, more preferably 100 to 140 ° C.
The development time is preferably from 1 to 180 seconds, more preferably from 10 to 90 seconds.

The photosensitive material of the present invention may be exposed by any method, but a laser beam is preferred as an exposure light source.
As the laser beam according to the present invention, gas laser, YAG
Lasers, dye lasers, semiconductor lasers and the like are preferred. Further, a semiconductor laser and a second harmonic generation element can be used. The light-sensitive material of the present invention has a low haze at the time of exposure and tends to generate interference fringes. As the interference fringe generation prevention technology, a technology disclosed in Japanese Patent Application Laid-Open No. 5-113548 or the like that obliquely enters a laser beam into a photosensitive material or a multi-mode laser disclosed in WO95 / 31754 or the like is used. There are known methods for performing these methods, and it is preferable to use these techniques. To expose the photosensitive material of the present invention, SPIE vol.169 Laser Printing pages 116-128 (197
9), it is preferable to expose the laser beams so as to overlap each other so as to make the scanning lines invisible, as disclosed in JP-A-4-51043 and WO95 / 31754.

[0090]

【Example】

Example 1 << Preparation of Silver Dispersion of Organic Acid >> 7 g of stearic acid, 4 g of arachidic acid, 36 g of behenic acid, and 850 ml of distilled water were added with vigorous stirring at 90 ° C. while adding 187 ml of 1N-NaOH aqueous solution, and reacted for 120 minutes. After adding 71 ml of nitric acid, the temperature was lowered to 50 ° C. Then, while stirring more vigorously, 125 ml of an aqueous solution of 21 g of silver nitrate
Was added over 100 seconds and allowed to stand for 20 minutes. Thereafter, the solid content was separated by suction filtration, and the solid content was washed with water until the conductivity of the filtrate became 30 μS / cm. The solid content thus obtained
PVA205 (Kuraray Co., Ltd. polyvinyl alcohol) 10w
100 g of a t% aqueous solution was added, and water was further added to a total weight of 270 g, followed by elementary dispersion in an automatic mortar to obtain a silver organic acid dispersion. This silver organic acid dispersion was dispersed at a pressure of 1000 kg / cm ³ at the time of collision using a Nanomizer (manufactured by Nanomizer) to obtain a silver organic acid dispersion. The organic acid silver particles contained in the organic acid silver dispersion thus obtained have an average minor axis of 0.04 μm and an average major axis of
The particles were needle-shaped particles having a size of 0.8 μm and a variation coefficient of 30%.

<< Preparation of Reducing Agent Dispersion >> 100 g of 1,1-bis (2-hydroxy-3,5-dimethylphenyl) -3,5,5-trimethylhexane and 850 g of water in 50 g of hydroxypropylcellulose
Was added and mixed well to obtain a slurry. Average diameter 0.5 mm
840 g of zirconia beads were prepared and placed in a vessel together with the slurry, and dispersed with a dispersing machine (1 / 4G sand grinder mill: manufactured by IMEX Co., Ltd.) for 5 hours to obtain a reducing agent dispersion.

<< Preparation of Organic Polyhalide Dispersion >> 940 g of water was added to 50 g of tribromomethylphenylsulfone and 10 g of hydroxypropylcellulose and mixed well to form a slurry. 840 g of zirconia beads with an average diameter of 0.5 mm
Prepare and put it in the vessel together with the slurry.
/ 4G Sand Grinder Mill: IMEX Co., Ltd.
For 5 hours to obtain an organic polyhalide dispersion.

<< Preparation of Silver Halide Particles >> After dissolving 22 g of phthalated gelatin and 30 mg of potassium bromide in 1000 ml of water and adjusting the pH to 5.0 at a temperature of 35 ° C., an aqueous solution containing 18.6 g of silver nitrate and 0.9 g of ammonium nitrate 159 ml of an aqueous solution containing potassium bromide and potassium iodide in a molar ratio of 92: 8
Control Double jet method while keeping pAg 7.7
It was added over a minute. Then, while maintaining at 476 ml of an aqueous solution containing 55.4 g of silver nitrate and 2 g of ammonium nitrate and an aqueous solution containing 10 μmol / l of dipotassium hexachloroiridate and 1 mol / l of potassium bromide at pAg7.7, a control double jet method was applied for 30 minutes. After the addition, 1 g of 4-hydroxy-6-methyl-1,3,3a, 7-tetrazaindene was added, and the pH was further lowered to cause coagulation and sedimentation for desalination. Then, 0.1 g of phenoxyethanol was added, and the pH was adjusted.
5.9, adjusted to pAg8.2, silver iodobromide grains (iodine content core 8
Preparation of a cubic grain (mol%, average 2 mol%, average size 0.05 μm, projection area variation coefficient 8%, (100) face ratio 85%).

The silver halide grains thus obtained were heated to 60 ° C., and 85 μmol of sodium thiosulfate and 2,2
11 μmol of 3,4,5,6-pentafluorophenyldiphenylphosphine selenide, 15 μmol of a tellurium compound, 3 μmol of chloroauric acid, and 270 μmol of thiocyanic acid were added, and 120
After ripening for 40 minutes, the mixture was rapidly cooled to 40 ° C., and 100 μmol of the dye and 500 μmol of 2-mercapto-5-methylbenzimidazole were added, and the mixture was rapidly cooled to 30 ° C. to obtain a silver halide emulsion.

<< Preparation of Emulsion Layer Coating Solution >> Organic Acid Silver Dispersion 13
50g, PVA205 20wt% aqueous solution 140cc, phthalazine 10wt
% Aqueous solution 37 cc, reducing agent dispersion 220 g, and the above organic polyhalide dispersion 61 g were added. Then, LACSTAR 3307B (manufactured by Dainippon Ink and Chemicals, Inc .; styrene and butadiene as main copolymerization components) SBR latex containing; average particle size of dispersed particles 0.1 to 0.15 μm, 25 ° C 60
An emulsion layer coating solution was prepared by mixing 1100 g of the polymer under equilibrium water content of 0.6 wt% under the condition of% RH, and then mixing 120 g of the above silver halide emulsion. (Table 1 shows the temperature and time after mixing Luck Star 3307B)

<< Preparation of Emulsion Surface Intermediate Layer Coating Solution >> 100 g of MP203 (modified polyvinyl alcohol manufactured by Kuraray Co., Ltd.)
Then, 2 cc of a 5 wt% aqueous solution of sodium sulfosuccinate di (2-ethylhexyl) ester was added.

<< Preparation of Coating Solution for Emulsion Surface Protective Layer >> In a solution prepared by dissolving 145 g of inert gelatin in 1110 cc of warm water, 20 wt% was added.
400 g of polyethyl acrylate latex, 1N-sulfuric acid 57
Then, 10 cc of a 5 wt% aqueous solution of sodium sulfosuccinate di (2-ethylhexyl) ester and 280 cc of a 10 wt% methanol solution of phthalic acid were added to obtain a coating solution for the protective layer.

<< Preparation of Coating Solution for Emulsion Surface Overcoat Layer >>
In a solution of 129 g of inert gelatin in 1650 cc of warm water, fine particles of polymethyl methacrylate (average particle size
130 g of a gelatin dispersion containing 2.5 wt.
Flow rate ratio of 2 wt% aqueous solution of potassium chromium (III) sulfate (hardening agent) 0.3 to liquid 1 containing 65 cc of sulfuric acid and 20 cc of 5 wt% aqueous solution of sodium di (2-ethylhexyl) sulfosuccinate ester sodium salt Thus, an overcoat layer coating solution was continuously prepared.

<< Back Layer Coating Solution >> A solid base such as N, N ',
10 g of a salt of N ", N"'-tetraethylguanidine and 4-carboxysulfonyl-phenylsulfone in a molar ratio of 1: 2 was dispersed in 10 g of polyvinyl alcohol, 88 g of water and a 1 / 16G sand grinder mill (manufactured by Imex Co., Ltd.). A base solution was obtained. Basic dye precursor 2.1 g, acidic substance 7.9 g, dye 0.
An organic solvent phase obtained by mixing and dissolving 1 g and 10 g of ethyl acetate was mixed with an aqueous phase composed of 10 g of polyvinyl alcohol and 80 g of water, and emulsified and dispersed at room temperature to obtain a dye solution (average particle size of 2.5 μm).
m). 39 g of the base solution thus obtained, 26 g of the dye solution, and 36 g of a 10 wt% aqueous solution of polyvinyl alcohol were mixed to obtain a back surface coating solution.

<< Coating solution for back surface protective layer >> 20 g of gelatin,
0.6 g of polymethyl methacrylate (average particle size: 7 μm), 0.4 g of sodium dodecylbenzenesulfonate, and 1 g of X-22-2809 (silicone compound manufactured by Shin-Etsu Silicone Co., Ltd.) are dissolved in 480 g of water to obtain a coating solution for the back surface protective layer. Was.

<< Preparation of Undercoating Coating Liquid A >> Polystyrene fine particles (average particle size: 0.2
μm) 50 g and surfactant A (1% by weight) 20 ml were added.
Distilled water was added to this to make 1000 ml, thereby obtaining an undercoating coating solution A.

[0102]

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<< Preparation of Undercoat Coating Solution B >> 200 ml of an aqueous dispersion of a styrene-butadiene copolymer (styrene / butadiene / itaconic acid = 47/50/3 (weight ratio), concentration: 30% by weight) in 680 ml of distilled water, polystyrene Fine particles (average particle size 2.5 μm)
0.1 g was further added, and distilled water was further added to make 1000 ml, thereby obtaining an undercoating coating solution B.

<< Preparation of Undercoating Coating Solution C >> 10 g of inert gelatin was dissolved in 500 ml of distilled water.
40 g of an aqueous dispersion (40% by weight) of the tin oxide-antimony oxide composite fine particles described in (1) above was added, and distilled water was added thereto to make 1000 ml, thereby obtaining an undercoating coating solution C.

<< Preparation of Undercoating Support >> One surface (photosensitive surface) of a biaxially stretched polyethylene terephthalate support having a thickness of 175 μm and colored with the following blue dye was subjected to a corona discharge treatment. Use a bar coater so that the wet coating amount is 5 cc / m ² ,
Dried for minutes. The dry film thickness was about 0.3 μm. Next, after applying a corona discharge treatment to the back surface (back surface), the undercoating coating solution B was applied using a bar coater so that the wet coating amount was 5 cc / m ² and the dry film thickness was about 0.3 μm. After drying at 180 ° C. for 5 minutes, the undercoating solution C was further coated thereon with a bar coater at a wet application amount of 3 cc / cm.
m ² , applied to a dry film thickness of about 0.03μm, 180 ℃
For 5 minutes to prepare an undercoat support.

[0106]

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<< Preparation of Thermal Image Forming Material >> The undercoating support was coated with the back layer coating solution at 50 g / m ² at a flow rate at which the optical density of 647 nm was 0.7, and the pressure was 0.7 g / m ^2.
tler, Petert M. Schweizer “LIQUID FILM COATING
Figure 11b on page 427 (published by CHAPMAN & HALL, 1997).
After simultaneously coated in the same coater as 1, the emulsion layer coating solution 82cc / m ² from the support side to the opposite surface and the back surface, the intermediate layer coating solution 6.5 cc / m ^2, the protective layer coating solution 12.5 cc / m ² , Overcoat layer coating solution 12 cc / m ²
After passing through a chilled zone with a dew point of 0 ° C or less, 30 ° C40
% RH Air was dried at a wind speed of 20 m / sec. The smoothness of the light-sensitive material thus obtained (the Beck smoothness was determined using Oken-type smoothness measurement described in J. TAPPI paper pulp test method No. 5) was determined on emulsion surface 60.
It was 0 seconds and the back surface was 85 seconds.

[0108]

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[0109]

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(Evaluation of Planar State) The state of the streaks generated per 10 cm of the coating width of the obtained coated product was visually evaluated. (Evaluation of photographic performance) 660nm semiconductor laser (maximum output 30
After exposing the photographic material to an inclination of 30 degrees with respect to the normal line (mW), the photographic material was processed (developed) at 120 ° C. for 15 seconds, and it was confirmed that all the samples formed thermal images.

[0111]

[Table 1]

It can be seen that the sample of the present invention is excellent.

Example 2 In the preparation of the emulsion layer coating solution of the light-sensitive material of Example 1, silver halide was added and mixed with a static mixer, and the same results as in Example 1 were obtained.

[0114]

According to the present invention, a thermal image forming material having a good surface condition and excellent image forming ability can be obtained.

Claims (6)

[Claims] In a method for producing a thermal image forming material, a coating solution for a thermal image forming layer containing an organic silver salt and a polymer latex is coated and dried on a support. A method for producing a thermal image forming material, characterized in that, after mixing, 30 minutes or more and 24 hours or less elapse, and then the coating solution is applied on a support. 2. The method according to claim 1, wherein after the organic silver salt and the polymer latex are mixed in the coating solution, the coating is carried out at 30 ° C. to 65 ° C. for 30 minutes to 24 hours.
3. The method for producing a thermal image forming material according to item 1. 3. The method for producing a thermal image forming material according to claim 1, wherein 50% or more of the solvent of the coating solution for the thermal image forming layer is water. 4. The method according to claim 1, wherein the polymer latex is an aqueous dispersion and the polymer has an equilibrium water content at 25 ° C. and 60% RH of 0.01% by weight or more and 2% by weight or less. Or a method for producing a thermal image forming material according to item 3. 5. The method according to claim 1, wherein the thermal image forming layer contains a reducing agent for a photosensitive silver halide and an organic silver salt. 6. The method for producing a thermal image forming material according to claim 1, wherein the organic silver salt is an organic silver carboxylate.