JPH11344790A - Silver halide photographic sensitive material for heat development - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a silver halide photographic sensitive material for heat development which does not undergo the lowering of the sensitivity and has improved preservability of an image by incorporating at least one of specified heat responsive microcapsules contg. an oxidizing agent into a recording layer. SOLUTION: The silver halide photographic sensitive material contains at least one of heat responsive microcapsules contg. an oxidizing agent in a recording layer or contains heat responsive microcapsules contg. at least one of compds. represented by the formulae R-SO2 -SM, R-SO2 S-R1 and R-SO2 S-Lm -SSO2 - R2 in the recording layer. Heat responsive microcapsules isolate an included substance at ordinary temp., and when the microcapsules are heated, the walls of the microcapsules are made permeable to the substance without destruction by pressure, heat, etc. In the formula, R, R1 and R2 may be the same or different and are each an aliphatic, arom. or heterocyclic group, M is a cation, L is a divalent combining group and (m) is 0 or 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording material for producing an image by dry processing, and more particularly, to a silver halide photographic light-sensitive material for thermal development having improved storage stability with time.

[0002]

2. Description of the Related Art While maintaining the sensitivity, rich gradation and good image quality of silver halide, the disadvantages of wet processing of silver halide are eliminated, and as a practical dry-processed light-sensitive material, US 3M Dry silver developed by the company is famous. This dry silver contains a colorless or white organic silver salt as a supply source of silver ions. When the reducing agent is heated to 100 ° C. or more in the presence of the exposed silver halide, the oxidation-reduction reaction occurs. Produces a silver image.
As the organic silver salt, silver behenate is preferably used as a practically used compound.

By the way, in such a dry silver photosensitive material, photosensitive silver halide particles and a reducing agent are present in the photosensitive material even after thermal development. For this reason, the heat-developed photosensitive material has disadvantages such as generation of fog and improvement in image density during the storage period.

It is known to add an inhibitor in order to improve the storage stability. However, if the amount of the inhibitor is increased, a significant decrease in sensitivity occurs, which is not practically preferable.

[0005]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a heat-developable light-sensitive material which has no deterioration in sensitivity and has improved storage stability over time.

[0006]

The object of the present invention has been solved by the following constitution.

(1) In a heat-developable silver halide photographic light-sensitive material having a recording layer composed of photosensitive silver halide grains, an organic silver salt and a reducing agent on a support,
A silver halide photographic light-sensitive material for thermal development, comprising at least one kind of heat-responsive microcapsules containing an oxidizing agent.

(2) The recording layer contains heat-responsive microcapsules containing at least one selected from compounds represented by the following general formulas (1) to (3). The silver halide photographic light-sensitive material for thermal development according to (1).

General formula (1) R-SO ₂ SM General formula (2) R-SO ₂ S-R ₁ General formula (3) R-SO ₂ S-Lm-SSO ₂ -R _{2 wherein} R, R ₁ and R ₂ may be the same or different and each represents an aliphatic group, an aromatic group or a heterocyclic group, and M represents a cation. L represents a divalent linking group, and m is 0 or 1.

(3) In a silver halide photographic light-sensitive material for thermal development having a recording layer comprising a photosensitive silver halide particle, an organic silver salt and a reducing agent on a support, the recording layer contains halogen. A silver halide photographic light-sensitive material for thermal development, comprising at least one kind of heat-responsive microcapsules containing a compound capable of releasing a compound.

(4) In a silver halide photographic light-sensitive material for thermal development having a recording layer comprising photosensitive silver halide grains, an organic silver salt and a reducing agent on a support, the recording layer comprises:
A silver halide photographic light-sensitive material for thermal development, comprising at least one kind of heat-responsive microcapsules containing iodine.

(5) In a silver halide photographic light-sensitive material for thermal development having a recording layer comprising a photosensitive silver halide particle, an organic silver salt and a reducing agent on a support, the recording layer comprises:
At least one of thermoresponsive microcapsules containing acid
A silver halide photographic light-sensitive material for thermal development, comprising a seed.

Hereinafter, the present invention will be described in detail.

The heat-responsive microcapsules used in the present invention are capable of isolating substances contained therein at normal temperature, and are not destroyed by pressure or heat during heating.
A microcapsule in which the wall of the microcapsule becomes material permeable.

As a method for producing such microcapsules, any of an interfacial polymerization method, an internal polymerization method, and an external polymerization method can be employed. In particular, an oxidizing agent or an acid is dissolved or dispersed in an organic solvent. It is preferred to employ an interfacial polymerization method in which the core material is emulsified in an aqueous solution in which a water-soluble polymer is dissolved, and then walls of the polymer material are formed around the oil droplets.

Examples of the organic solvent include carboxylic esters such as ethyl acetate and butyl acetate, toluene, xylene, and the like.
It is preferable to use a non-aqueous solvent having a boiling point of 150 ° C. or lower such as a phosphoric ester. It is added inside and / or outside the oil droplets of the reactant oil that forms the polymer substance.

Specific examples of the polymer substance include polyurethane, polyurea, polyamide, polyester, polycarbonate, urea-formaldehyde resin, polyamic acid, polystyrene, styrene methacrylate copolymer,
Styrene-acrylate copolymer and the like can be mentioned. Preferred polymer substances are polyurethane, polyurea, polyamide, polyester, and polycarbonate. Particularly, polyurethane and polyurea are preferable because capsules that are hard to break are obtained. Two or more polymer substances can be used in combination.

Specific examples of the water-soluble polymer include gelatin, polyvinylpyrrolidone, and polyvinyl alcohol. For example, when polyurea or polyurethane is used as the capsule wall material, diisocyanate, triisocyanate, tetraisocyanate, polyisocyanate such as polyisocyanate prepolymer and diamine, triamine, polyamine such as tetraamine, amino A prepolymer containing two or more groups, piperazine or a derivative thereof, a polyhydric alcohol, or water,
By reacting in an aqueous solvent by an interfacial polymerization method, microcapsule walls can be easily formed. Microcapsules in this case are particularly preferred because their walls are dense.

For the composite wall composed of polyurea and polyamide or the composite wall composed of polyurethane and polyamide, for example, the pH of an emulsifying medium as a reaction solution is adjusted by using polyisocyanate and acid chloride or polyamine and polyhydric alcohol. It can be prepared by post-heating. For details of the method for producing a composite wall comprising these polyurea and polyamide, see JP-A-58-1983.
No. 66948. The capsule made of polyamic acid is formed, for example, by an interfacial reaction between a polystyrene-maleic anhydride copolymer and a polyvalent amine.

Further, in order to swell the microcapsule wall when heated, a sensitizer may be added in an emulsified state or a solid state. The sensitizer is a polymer plasticizer used as a microcapsule wall.
Those having a melting point of 50 ° C. or higher, preferably 150 ° C. or lower and solid at ordinary temperature can be selected and used. For example, when the wall material is composed of polyurea or polyurethane, a hydroxy compound, a carbamate compound,
Aromatic alkoxy compounds, organic sulfonamide compounds,
Aliphatic amide compounds, aryl amide compounds and the like are preferably used.

In the present invention, the term "oxidizing agent" refers to a compound which acts on metallic silver to convert it into silver ions. In particular, compounds that convert fine silver atoms formed in silver halide grains into silver ions are effective.

The oxidizing agent used in the present invention includes hydrogen peroxide (water) and an adduct of hydrogen peroxide (eg, NaBO ₂
・ H ₂ O ₂ .3H ₂ O, 2NaCO ₃ .3H ₂ O ₂ , Na ₄ P _{2
O 7 · 2H 2 O 2,} 2Na 2 SO 4 · 2H 2 O 2 · 2H 2 O),
Peroxy acid salts (for example, K ₂ S ₂ O ₈ , K ₂ C ₂ O ₆ , K ₂ P ₂
O ₈ ), a peroxy complex compound (for example, K ₂ ｛Ti
(O ₂ ) C ₂ O ₄ ｝ · 3H ₂ O, 4K ₂ SO ₄ · Ti (O ₂ )
_{OH · SO 4 · 2H 2 O} , Na 3 {VO (O 2) (C 2 O 4)
₂ · 6H ₂ O}), permanganate (e.g. KMn
O _4), chromates (e.g. K ₂ Cr ₂ O _7), potassium hexacyanoferrate third ferrate, potassium iodate, inorganic oxidizing agents such as oxygen acid salts and halogen elements P- quinones such,
Organic oxidizing agents such as organic peroxides (for example, peracetic acid and perbenzoic acid) can be mentioned. Other oxidizing gases (for example, ozone and oxygen gas), oxidizing compounds that release halogen atoms (for example, sodium hypochlorite, N-bromosuccinimide, chloramine B (sodium benzene sulfone chloramide), chloramine T (sodium para) Oxidizing compounds such as toluenesulfonchloramide) can also be used.

Further, in the present invention, the following general formula (1):
The compounds represented by (2) and (3) can also be used.

General formula (1) R-SO ₂ SM General formula (2) R-SO ₂ S-R ₁ General formula (3) R-SO ₂ S-Lm-SSO ₂ -R _{2 wherein} R, R ₁ and R ₂ may be the same or different and each represents an aliphatic group, an aromatic group or a heterocyclic group, and M represents a cation. L represents a divalent linking group, and m is 0 or 1.

These compounds may be polymers containing, as a repeating unit, a divalent group derived from the structure represented by the general formula. R, R ₁ , R ₂ , and L may combine with each other to form a ring. The general formula (1),
The compounds represented by (2) and (3) will be described in more detail.

When R, R ₁ and R ₂ are an aliphatic group, they are preferably an alkyl group having 1 to 22 carbon atoms, an alkenyl group having 2 to 22 carbon atoms and an alkynyl group. May have. Examples of the alkyl group include methyl, ethyl, propyl, butyl, pentyl, hexyl, octyl, 2-ethylhexyl, decyl, dodecyl, hexadecyl, octadecyl, cyclohexyl, isopropyl,
and groups such as t-butyl. Examples of the alkenyl group include groups such as allyl and butenyl. Alkynyl groups include groups such as propargyl and butynyl.

When R, R ₁ and R ₂ are aromatic groups, they preferably have 6 to 20 carbon atoms and include groups such as phenyl and naphthyl. These may be substituted.

When R, R ₁ and R ₂ are heterocyclic groups, nitrogen,
Oxygen, sulfur, selenium, 3- to 15-membered ring having at least one element selected from tellurium, pyrrolidine, piperidine, pyridine, tetrahydrofuran, thiophene, oxazole, thiazole, imidazole, benzothiazole, benzoxazole, benzimidazole, Selenazole, benzoselenazole, tetrazole, triazole, benzotriazole, oxadiazole, thiadiazole and the like can be mentioned.

Examples of the substituent which R, R ₁ and R ₂ may have include an alkyl group (methyl, ethyl, hexyl, etc.), an alkoxy group (methoxy, ethoxy, octyloxy, etc.),
Aryl group (phenyl, naphthyl, tolyl group), hydroxy group, halogen atom, aryloxy group (phenoxy, etc.), alkylthio group (methylthio, butylthio, etc.),
Arylthio group (phenylthio etc.), acyl group (acetyl, propionyl, butyryl, valeryl etc.), sulfonyl group (methylsulfonyl, phenylsulfonyl etc.), acylamino group (acetylamino, benzamino etc.), sulfonylamino etc. (methanesulfonylamino, benzyl) Sulfonylamino), acyloxy group (acetoxy, benzoxy, etc.), carboxy group, cyano group, sulfo group, amino group and the like.

L is preferably a divalent aliphatic group or 2
Is a valent aromatic group. As the divalent aliphatic group, for example,

[0031]

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Xylylene groups and the like are mentioned, and divalent aromatic groups include phenylene and naphthylene.

These linking groups may be substituted with the aforementioned substituents.

[0034] M is preferably a metal ion or an organic cation. Examples of the metal ion include a lithium ion, a sodium ion, and a potassium ion.
Examples of the organic cation include an ammonium ion (ammonium, tetramethylammonium, tetrabutylammonium), a phosphonium ion (such as tetraphenylphosphonium), and a guanidine group.

Specific examples of the compounds are shown below, but are not limited thereto.

[0036]

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[0037]

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[0038]

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[0039]

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[0040]

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[0041]

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[0042]

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[0043]

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In the present invention, preferred oxidizing agents are compounds represented by the general formulas (1) to (3), halogen releasing compounds and iodine. Examples of the halogen releasing compound include, but are not limited to, the following compounds.

[0045]

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In the present invention, heat-responsive microcapsules containing an acid are used. The acid in the present invention is:
Refers to a compound capable of releasing hydrogen atoms in water,
Commonly known inorganic or organic acids can be used.

Specific examples include inorganic acids such as hydrochloric acid, sulfuric acid, sulfurous acid, nitric acid, nitrous acid, phosphoric acid and phosphorous acid, and compounds having a carboxyl group such as formic acid, acetic acid, propionic acid, butyric acid, phthalic acid, and the like. Benzoic acid, succinic acid, tartaric acid and the like can be mentioned.

In the present invention, the amount of the heat-responsive microcapsules used is from 5 g to 1 mol of the photosensitive silver halide.
It may be 60 g, and more preferably 20 g to 40 g.

In the present invention, the above general formulas (1) to (5)
The amount of the compound (3), the compound capable of releasing a halogen, iodine and the like, and the acid may be used in an amount of 0.05 g to 30 g, more preferably 0.1 g to 1 mol of the photosensitive silver halide.
1 g to 10 g.

Photosensitive materials for forming photographic images by using a heat development processing method are described in, for example, US Pat. Nos. 3,152,904 and 3,457,075; Morgan
n) and B. "Thermal Proc Silver System" by Shelly
essed Silver Systems), Sturge, V.E. Wallworth
or)). "Imaging Processes and Materials" edited by Shepp
materials, 8th edition, page 2. Neblett
e 1969).

Such a light-sensitive material includes a reducible non-photosensitive silver source (for example, an organic silver salt), a catalytically active amount of a photocatalyst (for example, silver halide), a color tone controlling agent for controlling the color tone of silver, and a reducing agent. Is usually dispersed in an (organic) binder matrix. The photosensitive material is stable at room temperature, but is exposed to high temperature (for example, 80 ° C. or higher, usually 80 ° C. to 3
(00 ° C.), silver is produced through a redox reaction between a reducible silver source (which functions 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. Silver produced by the reaction of the reducible silver salt in the exposed area provides a black image;
This is in contrast to the unexposed areas, where the image is formed.

As a method of causing a heat phenomenon, a method in which the heat drum is heated to a high temperature and the photosensitive material is brought into contact is preferable. Further, the heat development time is preferably from 1 second to 120 seconds.

The method for preparing the photosensitive silver halide grains in the present invention may be a method well known in the art, for example, Research Disclosure (RD) 17029.
(June 1978), and U.S. Patent 3,700,458.
Can be used.

As a specific method that can be used in the present invention, a part of the silver of the organic silver salt is converted into photosensitive silver halide by adding a halogen-containing compound to the prepared organic silver salt. A method in which a silver-supplying compound and a halogen-supplying compound are added to a solution of gelatin or another polymer to prepare photosensitive silver halide grains and mixed with an organic silver salt can be used. In the present invention, the latter method can be preferably used.

The particle size of the photosensitive silver halide is preferably small for the purpose of suppressing white turbidity in image formation.
Specifically, the average particle size is 0.01 μm to 0.4 μm, preferably 0.01 μm to 0.1 μm, and more preferably 0.01 μm to 0.08 μm. Here, the grain size refers to 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, and 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 100: 1 to 2: 1, more preferably 50: 1 to 3:
1 is good. 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. However, the spectral sensitization efficiency when the spectral sensitizing dye is adsorbed is high. preferable. The ratio is preferably 50% or more.
% Or more, more preferably 80% or more. The ratio of the {100} plane of the Miller index is determined by the T.I. Tani: J. et al. Imaging Sci. , 2
9, 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%, 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,
As a preferred example, silver iodobromide grains having a high silver iodide content inside the grains can be used. Preferably, silver halide grains having a core / shell structure can be used. As the structure, core / shell particles having preferably a 2- to 5-layer structure, more preferably a 2- to 4-layer structure, 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 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 preferred content is 1 × per mole of silver.
The range is preferably from 10 ^-9 mol to 1 × 10 ^-2 mol,
The range is more preferably from 10 ^-8 mol to 1 × 10 ^-4 . 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 are shown below.

[Fe (CN) ₆ ] ^4- [Fe (CN) ₆ ] ^3- [Co (CN) ₆ ] ³ Even if the phase containing the metal complex in silver halide is uniform, the core portion has a high concentration. It may be contained, or may be contained in the shell portion at a high concentration, 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 and a flocculation method, but in the present invention, they may or may not be desalted. Good.

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. In addition, a noble metal sensitization method or a reduction sensitization method of a gold compound, platinum, palladium, 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, diacyl tellurides, bis (oxycarbonyl) ditellurides, bis (carbamoyl) ditellurides, Compounds having a P = Te bond, tellurocarboxylates, Te-organyltellurocarboxylates, di (poly) tellurides, tellurides, tellurols, telluroacetals, tellurosulfonates, having a P-Te bond Compounds, 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, and US Pat.
No. 8,060 and British Patent No. 618061 can be preferably used. As specific compounds for the reduction sensitization method, in addition to ascorbic acid and thiourea dioxide, for example, stannous chloride, aminoiminomethanesulfinic acid, hydrazine derivatives, borane compounds, silane compounds, polyamine compounds and the like can be used. .
Further, 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 coated silver of the photosensitive silver halide of the present invention is as follows: the coated amount per 1 m ² of the support (photosensitive material).
From the viewpoint of haze, 0.5 g / m ² or less, further 0.1
Is preferably to 0.5 g / m ^2. The amount of the photosensitive silver halide used in the invention is preferably from 0.01 mol to 0.5 mol, more preferably from 0.02 mol to 0.3 mol, per 1 mol of the organic silver salt. Is more preferable, and 0.03 mol or more and 0.25 mol or less are particularly preferable. 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 the organic silver salt are respectively mixed with a high-speed stirrer, a ball mill, a sand mill, a colloid mill, a vibration mill, There is a method of mixing with a homogenizer or the like, 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 appear sufficiently.

The organic silver salt that can be used in the present invention is
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 may be any organic substance having the ability to reduce silver ions. Silver salts of organic acids,
Particularly (having 10 to 30 carbon atoms, preferably 15 to 28 carbon atoms)
Silver salts of long chain fatty carboxylic acids are preferred. The ligand is 4.0
Complexes of organic or inorganic silver salts having a complex stability constant in the range of １10.0 are also preferred. The silver donor can preferably comprise about 5 to 30% by weight of the imaging layer. Preferred organic silver salts include silver salts of organic compounds having a carboxy 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 stearate, silver oleate, silver laurate, silver caproate, silver myristate, silver palmitate, silver maleate, silver fumarate, and tartaric acid. Silver, 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, 2-mercapto-
5-aminothiadiazole silver salt, 2- (ethylglycolamide) benzothiazole silver salt, S-alkylthioglycolic acid (where the alkyl group has 12 to 2 carbon atoms)
2), a silver salt of dithiocarboxylic acid such as a silver salt of dithioacetic acid, a silver salt of thioamide, 5-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, 3-amino-5-benzylthio-1,2,4-thiazole Silver salts of 1,2,4-mercaptothiazole derivatives such as silver salts, and 3- (3-
(Carboxyethyl) -4-methyl-4-thiazoline-2
-Silver salts of thione compounds such as silver salts of thione.

Further, a compound containing an imino group can 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. 4,220,
No. 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 Nos. 761,361 and 4,775,613 can also be used.

The shape of the organic silver salt that 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. As is well known in photosensitive silver halide photosensitive materials, the inverse relationship between the size of silver salt crystal grains and their covering power also holds in the photothermographic material of the present invention. When the size of the organic silver salt particles as the image forming portion is large, it means that the covering power is small and the image density is low. Therefore, it is necessary to reduce the size of the organic silver salt.

In the present invention, the minor axis is from 0.01 μm to
0.20 μm, the major axis is preferably 0.10 μm to 5.0 μm, the minor axis is 0.01 μm to 0.15 μm, and the major axis is 0.10 μm.
μm to 4.0 μm is more preferred.

The particle size distribution of the organic silver salt is preferably monodispersed. Monodispersion means the percentage of the value obtained by dividing the standard deviation of the length of each of the minor axis and major axis by the minor axis and major axis, preferably 100% or less, more preferably 80% or less, and still more preferably 50% or less. It is. 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 for measuring the monodispersity, there is a method of obtaining the standard deviation of the volume-weighted average diameter of the organic silver salt, and the percentage variation coefficient of the value divided by the volume-weighted average diameter is preferably 100% or less, more preferably 8
0% or less, more preferably 50% or less. As a measuring method, for example, an organic silver salt dispersed in a liquid is irradiated with a laser beam, and the autocorrelation coefficient with respect to the time change of the fluctuation of the scattered light is obtained from the particle size (volume weight average diameter) obtained. be able to.

The light-sensitive silver halide emulsions and / or organic silver salts according to the invention are protected against the formation of additional fog by antifoggants, stabilizers and stabilizer precursors, and are sensitive during storage in stock. Can be stabilized. Suitable antifoggants, stabilizers and stabilizer precursors that can be used alone or in combination are
U.S. Pat. Nos. 2,131,038 and 2,694,71
Thiazonium salt described in US Pat. No. 6,886,4
Nos. 37 and 2,444,605; azaindene; U.S. Pat. No. 2,728,663; mercury salts; U.S. Pat. No. 3,287,135; urazole; U.S. Pat. No. 3,235,652. Sulfocatechol according to,
Oximes and nitroindazoles described in British Patent 623,448, polyvalent metal salts described in U.S. Patent 2,839,405, thyuronium salts described in U.S. Patent 3,220,839, and U.S. Patent 2,566 , 263 and 2,597,915, palladium, platinum and gold salts, U.S. Pat. Nos. 4,108,665 and 4,44.
No. 2,202, the halogen-substituted organic compounds described in U.S. Pat. Nos. 4,128,557 and 4,137,079;
Triazines described in U.S. Pat. Nos. 4,138,365 and 4,459,350 and U.S. Pat. No. 4,411,985
And the like.

Among them, preferred is JP-A-49-10
Nos. 724, 48-2842 and 48-8194, N-halogenosuccinimides,
-Halogenoacetamide, N-halogenoxazoline,
It is preferable to use an N-halogeno compound such as N-halogenobenzoazole or N-halogenobenzimidazole.

In the photosensitive emulsion layer of the present invention, a polyhydric alcohol (for example, glycerin and diol of the type described in US Pat. No. 2,960,404) as a plasticizer and a lubricant, and US Pat. Fatty acids or esters described in U.S. Pat. Nos. 765 and 3,121,060 and silicone resins described in British Patent No. 955,061 can be used.

A hardener may be used for each layer such as the photosensitive layer, protective layer and bag layer of the present invention. Examples of hardeners include:
U.S. Pat. No. 4,281,060, JP-A-6-20819
No. 3, polyisocyanates, epoxy compounds described in U.S. Pat. No. 4,791,042, vinyl sulfone compounds described in JP-A-62-89048, and the like. 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, JP-A-6
No. 2-170950, U.S. Pat. No. 5,382,504, and the like.
No. 44945, JP-A-63-188135, etc .; fluorinated surfactants described in U.S. Pat. No. 3,885,965;
Examples thereof include polyalkylene oxides and anionic surfactants described in No. 301140.

As the sensitizing dye in 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, holopolar cyanine dyes, styryl dyes, hemicyanine dyes, oxonol dyes, hemioxonol dyes and the like can be used.

Useful sensitizing dyes for use in the present invention include, for example, (RD) 17643, Section IV-A (Jan.
(Feb.), 1831, Section X (August 1979), or those described in the references cited.

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-
For the Ne laser light source, see Japanese Patent Application Laid-Open No.
Compounds I-1 to I-38 described in JP-A No.
Compounds I-1 to I-35 described in JP-A-5322 and compounds I-1 to I-34 described in JP-A-7-287338 and LED light sources are disclosed in JP-B-55-39818.
Dyes 1 to 20 described in JP-A-62-284343
Nos. I-1 to I-37 described in JP-A No.
The compounds of I-1 to I-34 described in -287338 are advantageously selected.

In particular, the silver halide grains are spectrally sensitized in any wavelength range from 750 to 1400 nm. Specifically, the photosensitive silver halide can be spectrally sensitized with various known dyes, including cyanine, merocyanine, styryl, hemicyanine, oxonol, hemioxonol, and xanthene dyes.
Useful cyanine dyes include, for example, thiazoline nuclei, oxazoline nuclei, pyrroline nuclei, pyridine nuclei, oxazole nuclei,
It is a cyanine dye having a basic nucleus such as a thiazole nucleus, a selenazole nucleus and an imidazole nucleus. 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-mentioned cyanine and merocyanine dyes, those having an imino group or a carboxyl group are particularly effective. For example, US Pat. No. 3,761,279,
3,719,495 and 3,877,943, British Patent 1,466,201, and 1,469,117
No. 1, 422, 057, Tokuhei 3-10391
No. 6-52387, JP-A-5-341432
JP-A-6-194781, JP-A-6-30114
The dye may be appropriately selected from known dyes as described in No. 1. A particularly preferred structure of the dye is a cyanine dye having a thioether bond, and examples thereof include JP-A Nos. 62-58239, 3-13838, and 3-1.
No. 38642, No. 4-255840, No. 5-7265
Nos. 9, 5-72661, 6-222491, 2-230506, 6-258775, 6-3
No. 17868, No. 6-324425, Tokiohei 7-50
No. 0926.

These sensitizing dyes may be used alone or in combination, and the 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.

Useful sensitizing dyes, combinations of dyes exhibiting supersensitization and substances exhibiting supersensitization are (RD) 17643.
IV, Section J (December 1978) or JP-B-49-25
No. 500, No. 43-4933, JP-A-59-1903.
2, No. 59-192242, and the like.

The sensitizing dyes used in the present invention may be used in combination of two or more. To add sensitizing dyes to a silver halide emulsion, they may be directly dispersed in the emulsion,
Alternatively, water, methanol, ethanol, propanol, acetone, methyl cellosolve, 2,2,3,3-tetrafluoropropanol, 2,2,2-trifluoroethanol, 3-methoxy-1-propanol, 3-methoxy-1- Butanol, 1-methoxy-2-propanol,
It may be dissolved in a solvent such as N, N-dimethylformamide alone or in a mixed solvent and added to the emulsion.

As disclosed in US Pat. No. 3,469,987, a dye is dissolved in a volatile organic solvent, and this solution is dispersed in water or a hydrophilic colloid. Method of adding to the inside, Japanese Patent Publication No. 44-2338
No. 9, No. 44-27555, No. 57-22091, etc., the dye is dissolved in an acid, and this solution is added to the emulsion, or the emulsion is prepared as an aqueous solution by co-existing an acid or a base. US Pat. No. 3,822,1
No. 35, 4,006,025, etc., a method of adding an aqueous solution or a colloidal dispersion in the presence of a surfactant to an emulsion as disclosed in JP-A-53-1
JP-A-51-7462, a method of directly dispersing a dye in a hydrophilic colloid and adding the dispersion to an emulsion as disclosed in JP-A Nos. 02733 and 58-105141.
As disclosed in No. 4, a method in which a dye is dissolved using a compound that causes a red shift, and this solution is added 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.
628,960, 4,183,756, 4,2
25,666; JP-A-58-184142;
As disclosed in, for example, JP-A-1966749, the stage before silver halide grain formation and / or desalting, the period during and / or after desalting and before the start of chemical ripening,
As disclosed in JP-A-58-113920,
It may be added at any time during the process just before or during the process of chemical ripening, or at any time after the chemical ripening and before coating, before the emulsion is coated.

Further, as disclosed in US Pat. No. 4,225,666, JP-A-58-7629, etc., the same compound may be used alone or in combination with a compound having a different structure, for example, during the particle forming step. Or during the chemical ripening step or after the completion of the chemical ripening, or may be added separately such as before or during the chemical ripening or after the completion of the chemical ripening. You may change and add it.

The reducing agent for the organic silver salt may be any substance that reduces silver ions to metal, 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 used in the image forming layer.
It should be present as 0% by weight. In a multi-layer configuration,
If the reducing agent is added to a layer other than the emulsion layer, a slightly higher proportion, about 2 to 15% by weight, tends to be more desirable.

A wide range of reducing agents have been disclosed for photothermographic materials utilizing organic silver salts. For example, phenylamide oxime, 2-thienylamide oxime and p
Amide oximes such as phenoxyphenylamide oxime; azines such as 4-hydroxy-3,5-dimethoxybenzaldehyde azine; such as the combination of 2,2'-bis (hydroxymethyl) propionyl-β-phenylhydrazine with ascorbic acid. A combination of a novel aliphatic carboxylic acid aryl hydroazide and ascorbic acid;
Combinations of polyhydroxybenzene and hydroxylamine, reductone and / or hydrazine (e.g. hydroquinone and bis (ethoxyethyl) hydroxylamine, piperidinohexose reductone or formyl-4
A combination of azine and sulfonamidophenol (eg, phenothiazine and 2,6-dichloro-4); hydroxamic acids such as phenylhydroxamic acid, p-hydroxyphenylhydroxamic acid and β-aniline hydroxamic acid; Α-cyanophenylacetic acid derivatives such as ethyl-α-cyano-2-methylphenylacetate and ethyl-α-cyanophenylacetate; 2,2′-dihydroxy-1,1′-binaphthyl; 6,6'-dibromo-2,2'-dihydroxy-
Bis-β-naphthol as exemplified by 1,1′-binaphthyl and bis (2-hydroxy-1-naphthyl) methane; bis-β-naphthol and 1,3-dihydroxybenzene derivatives (for example, 2,4- A combination of dihydroxybenzophenone or 2 ', 4'-dihydroxyacetophenone); 5-pyrazolone, such as 3-methyl-1-phenyl-5-pyrazolone; dimethylaminohexose reductone, anhydrodihydroaminohexose reductone And reductones as exemplified by anhydrodihydropiperidone hexose reductone; 2,6-
Sulfonamide phenol reducing agents such as dichloro-4-benzenesulfonamidophenol and p-benzenesulfonamidophenol; 2-phenylindane-1,
3-dione and the like; 2,2-dimethyl-7-t-butyl-
Chromans such as 6-hydroxychroman; 1,4-dihydropyridines such as 2,6-dimethoxy-3,5-dicarbethoxy-1,4-dihydropyridine; bisphenols (for example, bis (2-hydroxy-3-t-butyl) -5-methylphenyl) methane, 2,2-bis (4-hydroxy-3-3methylphenyl) 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, 1-ascorbyl palmitate, ascorbyl stearate, etc.); and aldehydes and ketones such as benzyl and biacetyl; 3-pyrazolidone and certain And indane-1,3-dione.

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.

In the present invention, a mercapto compound, a disulfide compound, and a thione compound are contained in order to suppress or accelerate development to control development, to improve spectral sensitization efficiency, to improve storage stability before and after development, and the like. be able to.

When a mercapto compound is used in the present invention, it may be of any structure,
Those represented by -SS-Ar 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 having one or more nitrogen, sulfur, oxygen, selenium or tellurium atoms. Preferably, the heteroaromatic ring is benzimidazole, naphthymidazole, benzothiazole, naphthothiazole, benzoxazole, naphthoxazole,
Benzoselenazole, benzoterzole, imidazole, oxazole, pyrazole, triazole, thiadiazole, tetrazole, triazine, pyrimidine, pyridazine, pyrazine, pyridine, purine, quinoline or quinazolinone. The heteroaromatic ring includes, for example, halogens (eg, Br and Cl), hydroxy, amino,
Carboxy, alkyl (eg, one or more carbon atoms,
Preferably those having 1 to 4 carbon atoms and alkoxy (e.g. one or more carbon atoms, preferably 1 to 4 carbon atoms).
Which have four carbon atoms). Examples of the mercapto-substituted heteroaromatic compound include 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-quinoline thiol,
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-hydroxy-2
-Mercaptopyrimidine, 2-mercaptopyrimidine,
4,6-diamino-2-mercaptopyrimidine, 2-mercapto-4-methylpyrimidine hydrochloride, 3-
Examples include mercapto-5-phenyl-1,2,4-triazole, 2-mercapto-4-phenyloxazole, and the like, but the invention is not limited thereto.

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 0.1 to 1.0 mol per mol of silver.
It is in an amount of from 0.01 to 0.3 mol.

The photothermographic material of the present invention may contain a soluble salt (for example, chloride or nitrate), a vapor-deposited metal layer, US Pat. Nos. 2,861,056 and 3,206 for the purpose of preventing static electricity or imparting conductivity. , 312 or a layer containing an insoluble inorganic salt as described in U.S. Pat. No. 3,428,451.

The photographic emulsions for thermal development in the present invention are coated by various coating operations including dip coating, air knife coating, flow coating or extrusion coating using a hopper of the type described in US Pat. No. 2,681,294. be able to. U.S. Pat. No. 2,761,791 and British Patent 837,
No. 095, two or more layers can be coated simultaneously.

Additional layers in the photothermographic material of the present invention,
For example, it may include a dye-receiving layer for receiving a mobile dye image, an opacifying layer if reflective printing is desired, a protective topcoat layer, and a primer layer known in the photothermographic art. 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 required for image formation such as an image receiving layer does not become another member.

The light-sensitive material of the present invention can be provided with a surface protective layer for the purpose of preventing adhesion of the image forming layer.
Any anti-adhesion material may be used as the surface protective layer. 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.

In the emulsion layer or the protective layer of the emulsion layer in the present invention, US Pat. No. 3,253,921, US Pat.
4,782, 2,527,583 and 2,95
It can be used in photographic elements containing light absorbing materials and filter dyes as described in US Pat. Further, a dye can be mordanted as described in U.S. Pat. No. 3,282,699.

In the emulsion layer or the protective layer of the emulsion layer in the present invention, a matting agent such as starch, titanium dioxide, zinc oxide, silica, described in US Pat. Nos. 2,992,101 and 2,701,245. Polymer beads, including the types of beads described, can be included. The matt degree of the emulsion surface may be any value as long as no stardust failure occurs, but the Beck smoothness is preferably 500 seconds or more and 10,000 seconds or less, and particularly preferably 1000 seconds or more and 10,000 seconds or less.

As the binder for the emulsion layer in the present invention, well-known natural or synthetic resins such as gelatin, polyvinyl acetal, polyvinyl chloride, polyvinyl acetate, cellulose acetate, polyolefin, polyester, polystyrene, polyacrylonitrile, polycarbonate, etc. You can select any from Of course, copolymers and terpolymers are also included. Preferred polymers are polyvinyl butyral, butylethyl cellulose, methacrylate copolymer, maleic anhydride copolymer, polystyrene and butadiene copolymer. If necessary, two or more of these polymers can be used in combination. Such a polymer is used in an amount sufficient to hold the components therein. That is, it is used in a range effective to function as a binder. The effective range can be appropriately determined by those skilled in the art. As a guideline for holding at least the organic silver salt, the ratio of the binder to the organic silver salt is 15:
The range of 1-1: 2, particularly 8: 1 to 1: 1 is preferred.

In some cases it may be advantageous to include, in addition to the above components, additives known as "toning agents", which enhance the image. For example, the toning material is 0.1% of the total silver holding component.
It may be present in an amount of from 10 to 10% by weight. Toning agents are materials well known in the photographic art, as shown in U.S. Patents 3,080,254, 3,847,612 and 4,123,282.

Examples of toning agents include phthalimide and N-hydroxyphthalimide; succinimide, pyrazoline-5
And cyclic imides such as quinazolinone, 3-phenyl-2-pyrazolin-5-one, 1-phenylurazole, quinazoline and 2,4-thiazolidinedione; naphthalimides (e.g. N-hydroxy-1,8
-Naphthalimide); cobalt complex (e.g., cobalt hexamine trifluoroacetate); 3-mercapto-1,2,4-triazole, 2,4-dimercaptopyrimidine, 3-mercapto-4,5-diphenyl-1,
2,4-triazole and 2,5-dimercapto-1,
Mercaptans exemplified by 3,4-thiadiazole; N
-(Aminomethyl) aryldicarboximide [for example, (N, N-dimethylaminomethyl) phthalimide and N, N- (dimethylaminomethyl) -naphthalene-
2,3-dicarboximide); and blocked pyrazoles, isothiuronium derivatives and certain photobleaching agents (eg, 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, phthalazinone derivative or metal salt, or 4- (1-naphthyl) phthalazinone, 6-chlorophthalazinone, 5,7-dimethoxyphthalazinone And a derivative such as 2,3-dihydro-1,4-phthalazinedione; a combination of phthalazinone and a phthalic acid derivative (for example, phthalic acid, 4-methylphthalic acid, 4-nitrophthalic acid and tetrachlorophthalic anhydride) Phthalazine, phthalazine derivatives or metal salts, or derivatives such as 4- (1-naphthyl) phthalazine, 6-chlorophthalazine, 5,7-dimethoxyphthalazine and 2,3-dihydrophthalazine; phthalazine and phthalic acid derivatives ( For example, phthalic acid, 4-methylphthalic acid, 4-nitrophthalic acid and tet Quinazolinedione, benzoxazine or naphthoxazine derivatives; rhodium complexes, such as hexachloro, which function not only as color tone regulators but also in-situ as sources of halide ions for silver halide formation Ammonium rhodate (III), rhodium bromide, rhodium nitrate and potassium hexachlororhodate (III);
Inorganic peroxides and persulfates, for example ammonium disulfide and hydrogen peroxide; 1,3-benzoxazine-
Benzoxazines such as 2,4-dione, 8-methyl-1,3-benzoxazine-2,4-dione and 6-nitro-1,3-benzoxazine-2,4-dione
2,4-dione; pyrimidine and asymmetric triazine (eg, 2,4-dihydroxypyrimidine, 2-hydroxy-4-aminopyrimidine, etc.), azauracil, and tetraazapentalene derivatives (eg, 3,6-dimercapto- 1,4-diphenyl-1H, 4H-2,3a,
5,6a-tetraazapentalene and 1,4-di (o
-Chlorophenyl) -3,6-dimercapto-1H, 4
H-2,3a, 5,6a-tetraazapentalene) and the like.

The photothermographic material of the present invention has at least one photosensitive layer containing a silver halide emulsion on one side of a support, and a back layer (backing layer) on the other side.
It is preferable that the material is a so-called single-sided photosensitive material.

The absorbance at the exposure wavelength of the back layer is preferably 0.1 or more and 2.0 or less in order to obtain the effect of the present invention.

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. Pat. Nos. 1,939,213, 2,701,245, 2,322,037, 3,2626,782, and 3,539, Organic matting agents described in JP-A-344, JP-A-3,767,448 and the like; JP-A-1,260,772, JP-A-2,1
Nos. 92,241, 3,257,206, 3,37
0,951, 3,523,022, 3,76
Inorganic matting agents such as those described in JP-A-9,020 and the like can be used. For example, specifically, examples of organic compounds that can be used as a matting agent include polymethyl acrylate, polymethyl methacrylate, polyacrylonitrile, acrylonitrile-α-methylstyrene copolymer, and polystyrene as examples of a water-dispersible vinyl polymer. , Styrene-divinylbenzene copolymer, polyvinyl acetate, polyethylene carbonate, polytetrafluoroethylene, etc., examples of cellulose derivatives such as methylcellulose, cellulose acetate, cellulose acetate propionate, and starch derivatives such as carboxy starch, carboxynitrophenyl Starch, urea-formaldehyde-starch reactants, etc.
Gelatin hardened with a known hardener, hardened gelatin coacervated into microcapsule hollow particles, and the like can be preferably used.

Examples of inorganic compounds include silicon dioxide, titanium dioxide, magnesium dioxide, aluminum oxide,
Barium sulfate, calcium carbonate, silver chloride desensitized by a known method, silver bromide, glass, diatomaceous earth and the like 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. In implementing the present invention, 0.1
It is preferable to use one having a particle size of from μm to 30 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 photosensitive material, the particle size, shape, and particle size distribution can be adjusted as necessary during the preparation of the matting agent or by mixing a plurality of matting agents. preferable.

In the present invention, the matting degree of the backing layer is preferably such that the Beck smoothness is 10 to 250 seconds, more preferably 50 to 180 seconds.

In the present invention, the matting agent is preferably contained in the outermost surface layer of the light-sensitive material, a layer functioning as the outermost surface layer, or a layer close to the outer surface. It is preferable to be contained.

In the present invention, suitable binders for the back layer are transparent or translucent, generally colorless, and natural polymer synthetic resins, polymers and copolymers, and other film-forming media such as: gelatin, gum arabic, poly (vinyl) Alcohol), hydroxyethylcellulose, cellulose acetate, cellulose acetate butyrate, poly (vinylpyrrolidone), casein, starch, poly (acrylic acid), poly (methyl methacrylic 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 (esters), Poly ( Urethane), phenoxy resin, 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.

When an antihalation dye is used in the present invention, the dye may be any compound as long as it has the desired absorption, the absorption in the visible region is sufficiently small, and the desired absorbance spectrum of the back layer is obtained. . For example,
JP-A-7-13295, U.S. Pat. No. 5,380,635
And the compounds described in JP-A-2-68539, page 13, lower left column, line 1 to lower left column, line 9, and JP-A-3-24539, page 14, lower left column to page 16, lower right column. However, the present invention is not limited to these.

US Pat. No. 4,460,681 and US Pat.
No. 374,921 discloses a backside resistive heating layer.
nglayer) can also be used in the photothermographic imaging system.

[0112]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

Example 1 <Preparation of silver halide grains> In 700 ml of water, 2.2 g of phthalated gelatin and 30 g of potassium bromide were dissolved, and the temperature was adjusted to 3
After adjusting the pH to 5.0 at 5 ° C., 18.6 g of silver nitrate was used.
And an aqueous solution containing potassium bromide and potassium iodide at a molar ratio of 92: 8 were added over 10 minutes by a control double jet method while maintaining the pAg at 7.7.

Next, an aqueous solution 4 containing 55.4 g of silver nitrate was used.
76 ml and an aqueous solution containing 10 μmol / l of dipotassium hexachloridate and 1 mol / l of potassium bromide were added over 30 minutes by the control double jet method while maintaining the pAg at 7.7. Thereafter, the pH was lowered to perform coagulation sedimentation and desalting treatment, and phenoxyethanol was added to a pH of 0.1.
15 g, pH 5.9 and pAg 8.2 were adjusted, and silver iodobromide grains (iodine content core 8 mol%, average 2 mol%, average grain size 0.05 μm, projection area variation coefficient 8%, (1
00) cubic particles having an area ratio of 88%).

The obtained silver halide emulsion was heated to 60 ° C., and 85 μmol of sodium thiosulfate and 11 μmol of 2,3,4,5,6-pentafluorophenyldiphenylphosphine selenide per mol of silver were added. Tellurium compound 1
15 μmol, chloroauric acid 3.0 μmol, thiocyanic acid 2
After adding 60 μmol and ripening for 120 minutes, the mixture was rapidly cooled to 30 ° C. to obtain a silver halide emulsion.

<Preparation of Organic Acid Silver Emulsion> Stearic acid
3 g, 0.5 g of arachidic acid, 8.5 g of behenic acid, and 300 ml of distilled water were mixed at 90 ° C. for 15 minutes, and 31.1 ml of a 1N aqueous NaOH solution was added over 15 minutes while stirring vigorously, and then the temperature was lowered to 30 ° C. did.

Then, 7 ml of a 1N phosphoric acid aqueous solution was added,
N-bromosuccinimide 0.
After the addition of 02 g, silver halide grains prepared in advance were added so that the amount of silver halide was 2.5 mmol. Further, 25 ml of a 1N aqueous solution of silver nitrate was added over 2 minutes, and stirring was continued for 90 minutes. Thereafter, the solid content was separated by suction filtration, and the conductivity of the solid content was 30 μm.
It was washed with water until it reached S / cm. In the solid content thus obtained,
37 g of a 1.2% by weight butyl acetate solution of polyvinyl acetate
Was added and stirred.

Then, the stirring was stopped and the mixture was allowed to stand. Then, the mixture was separated into an oil layer and an aqueous layer, and the aqueous layer was removed together with the contained salt to obtain an oil layer.
Next, 2.5 w of polyvinyl butyral (Denka Butyral # 3000-K manufactured by Denki Kagaku Kogyo Co., Ltd.) was added to this oil layer.
20 g of t% 2-butanone solution was added and stirred. Further, after 0.1 mmol of pyridinium perbromide and 0.15 mmol of calcium bromide dihydrate were added together with 0.7 g of methanol, 40 g of 2-butanone and 7 g of polyvinyl butyral (PVB.B-76 manufactured by Monsanto) were added. 0.8 g was added and dispersed with a homogenizer to form an organic acid silver emulsion (having an average particle size of 0.8).
Acicular particles having an average major axis of 1 μm and a variation coefficient of 30%) were obtained.

<Preparation of Microcapsule Solution Encapsulating Oxidizing Agent or Acid> The compound of the present invention encapsulated in capsules in the amounts shown in Table 1, 20.0 g of n-butyl acetate, 5.0 g of isopropyl alcohol and polyvinyl butyral 2 0.0g
, And mix with a homogenizer at 10,000 rpm.
For 2 hours. Takenate D- was added to the resulting dispersion.
8.0 g of 110N (capsule wall material) was added.

The obtained dispersion was treated with a 6% aqueous solution 4 of polyvinyl alcohol (PVA217E: manufactured by Kuraray Co., Ltd.).
0 g and 0.3 g of a 2% aqueous solution of dioctyl sodium sulfosuccinate were added to a mixed solution (aqueous phase), and emulsified and dispersed at 8,000 rpm for 10 minutes with a homogenizer.
15 g of water is added to the obtained emulsified dispersion and mixed uniformly,
The mixture was heated to 40 ° C. with stirring, and an encapsulation reaction was performed for 3 hours so that the average particle size of the capsules became 10 μm, to obtain a capsule liquid containing an oxidizing agent or an acid.

<Preparation of Emulsion Layer Coating Solution> Each of the chemicals was added to the above-obtained organic acid silver emulsion in the following amount per mole of silver halide. At 25 ° C., 30 g of the above capsule solution, 10 mg of sodium phenylthiosulfonate,
The following dye 1 (70 mg), dye 2 (30 mg), 2-mercapto-5-methylbenzimidazole (2 g), 4-chlorobenzophenone-2-carboxylic acid (21.5 g), 2-butanone (580 g), and dimethylformamide (220 g) were added with stirring. And left for 3 hours.

Next, the amount of 5-tribromomethylsulfonyl-2-methylthiadiazole shown in Table 1 was added, and 6 g of 2-tribromomethylsulfonylpentazothiazole and 4,6-ditrichloromethyl-2-phenyl were further added. 5 g of triazine and 2 of the following disulfide compound 1
g, 1,1-bis (2-hydroxy-3,5-dimethylphenyl) -3,5,5-trimethylhexane 155
g, 4.5 g of tetrachlorophthalic acid, Megafac F-
176P (Fluorine-based surfactant manufactured by Dainippon Ink and Chemicals, Inc.)
1.1 g, 590 g of 2-butanone, and 10 g of methyl isobutyl ketone were added with stirring. Byron 20
0 (polyester manufactured by Toyobo Co., Ltd.) was added in an amount of 31 g.

<Emulsion protective layer coating solution> CAB171-15
S (manufactured by Eastman Chemical Co., Ltd., cellulose acetate butyrate) 75 g, 4-methylphthalic acid 5.7 g, tetrachlorophthalic anhydride 1.5 g, phthalazine 12.5 g, Megafac F-176P 0.3 g, sill Decks H3
1 (average size of true spherical silica 3 μm manufactured by Dokai Chemical Co., Ltd.) 2
g, smidur N3500 (polyisocyanate manufactured by Sumitomo Bayer Urethane Co., Ltd.) 6 g to 2-butanone 3070
g and 30 g of ethyl acetate were prepared as a coating solution.

<Back Surface Coating Solution> Calcium Compound 1 was synthesized as follows.

An aqueous solution containing 0.019 mol of calcium chloride in 1 liter of an ethanol solution containing 0.08 mol of 3,5-di-tert-butylcatechol
7 ml and 125 ml of 25% aqueous ammonia were added, and air was blown at room temperature for 3 hours to obtain bis [2- (3,5-di-
tert-butyl-o-benzoquinonemonoimine)-
4,6-di-tert-butylphenolate] calcium (II) crystals (calcium compound 1) were precipitated.

Polyvinyl butyral (described above) 12 g, C
AB381-20 (supra) 12 g, dye 1 120 m
g, 350 mg of Dye 2, 5 mg of Dye 3, 300 mg of Calcium Compound 1, 0.4 g of Sildex H121 (manufactured by Dokai Chemical Co., average spherical silica 12 μm),
While stirring 0.4 g of Sildex H51 (manufactured by Dokai Chemical Co., Ltd., average spherical particle size 5 μm), 0.1 g of Megafac F-176P, and 2 g of sumidur-N3500, 500 g of 2-butanone and 500 g of 2-propanol were stirred. Added, dissolved and mixed.

The emulsion layer coating solution prepared as described above was coated on a 175 μm thick polyethylene terephthalate support which was tinted with Dye 2 to give a coating amount of 2.3 g / m ^2.
(0.23 g / m ² as silver halide), and then a backside coating solution was applied on the surface opposite to the emulsion layer to a dry thickness of 3 μm. Further, an emulsion protective layer coating solution was coated on the emulsion surface to a dry thickness of 2 μm.

The smoothness of the thus obtained light-sensitive material (J.
TAPPI paper pulp test method No. The Beck smoothness was determined using the Oken-type smoothness measurement described in Example 5).
Seconds and the back surface was 80 seconds. The additive compounds used above are shown below.

[0129]

Embedded image

[0130]

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<Evaluation of Sensitometry> The photothermographic material prepared as described above was exposed in a wedge shape using an exposure apparatus using a semiconductor laser of 810 nm as a light source.
A heat development treatment was performed at 115 ° C. for 15 seconds using a heat drum. In sensitometry, the reciprocal of the exposure energy that gives a density of 3.0 was used as the sensitivity, and the sample no. Sensitivity of 1 to 1
The relative sensitivity when the value was set to 00 was shown.

<Evaluation of Image Preservation> Two samples were prepared in the same manner as in sensitometry, and one of them was prepared.
The sheets were stored at 25 ° C. and 55% RH for 7 days under light shielding. Another one
The sheets were exposed to natural light at 25 ° C. and RH 55% for 7 days. Next, the density of the fogged portion was measured, and the fog value was determined by the following formula, and the image storability was evaluated.

Fog = (fog when exposed to natural light)
-(Fog when stored under light shielding) The results obtained are shown in Table 1 below.

[0134]

[Table 1]

* 1: Sample No. Sample No. 3 except that Compound 4-1 contained in Sample No. 3 was not included in the microcapsules but was added directly when preparing the coating solution. Those coated in the same manner as 3.

* 2: Sample No. Sample No. 6 was prepared except that Compound 1-1 contained in Sample No. 6 was not included in microcapsules, but was added directly when preparing a coating solution. Those coated in the same manner as 3.

As is clear from Table 1 above, it is found that the sample containing the compound of the present invention encapsulated in microcapsules maintains high sensitivity and has excellent image storability.

[0138]

As demonstrated in the Examples, according to the present invention, a heat-developable light-sensitive material having no sensitivity reduction and having a small fog increase value after storage of an image over time was obtained.

Claims (5)

[Claims] 1. A heat-sensitive silver halide photographic material having a recording layer comprising photosensitive silver halide grains, an organic silver salt and a reducing agent on a support, wherein an oxidizing agent is contained in the recording layer. A silver halide photographic light-sensitive material for thermal development, comprising at least one kind of heat-responsive microcapsules containing 2. The method according to claim 1, wherein the recording layer has the following general formula (1):
2. The silver halide photographic light-sensitive material for thermal development according to claim 1, further comprising thermoresponsive microcapsules containing at least one selected from the compounds represented by (3). Formula (1) R-SO ₂ SM Formula _{(2) R-SO 2 S} -R 1 in Formula (3) _{R-SO 2 S-Lm-} SSO 2 -R 2 Formula, R, R _1, R ₂ may be the same or different and represents an aliphatic group, an aromatic group or a heterocyclic group, and M represents a cation. L represents a divalent linking group, and m is 0 or 1. 3. A heat-developable silver halide photographic material having a recording layer comprising a photosensitive silver halide particle, an organic silver salt and a reducing agent on a support, wherein a halogen is contained in the recording layer. A silver halide photographic light-sensitive material for thermal development, comprising at least one kind of heat-responsive microcapsules containing a compound to be released. 4. In a silver halide photographic light-sensitive material for thermal development having a recording layer comprising photosensitive silver halide grains, an organic silver salt and a reducing agent on a support, iodine is added to the recording layer. A silver halide photographic light-sensitive material for thermal development, comprising at least one kind of thermoresponsive microcapsules. 5. In a silver halide photographic light-sensitive material for thermal development having a recording layer comprising photosensitive silver halide grains, an organic silver salt and a reducing agent on a support, an acid is added to the recording layer. A silver halide photographic light-sensitive material for thermal development, comprising at least one kind of thermoresponsive microcapsules.