JPH0579977B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a photographic material in which an image is formed by heat development, and more particularly to improving the shelf life of a heat-developable light-sensitive material containing an acid or an acid precursor. [Background of the Invention] In recent years, heat-developable photosensitive materials whose development process can be performed by heat treatment have attracted attention as photosensitive materials. Such heat-developable photosensitive materials are described in, for example, Japanese Patent Publication No. 43-4921 and No. 43-4924, which disclose photosensitive materials comprising an organic silver salt, silver halide, a reducing agent, and a binder. It is commercialized by 3M as dry silver. Attempts have been made to improve such heat-developable photosensitive materials and obtain color images by various methods. For example, U.S. Pat. Research Disclosure
15108 and 15127, U.S. Pat. No. 4,021,240, etc., a dye image is formed by the reaction of a coupler with an oxidized form of a reducing agent (hereinafter also referred to as a developer or developing agent), which is a sulfonamide phenol or sulfonamide aniline derivative. A method of releasing a dye image on a separately provided image-receiving layer by using an organic imino silver salt having a dye part as disclosed in British Patent No. 1590956, and releasing a dye image on a separately provided image-receiving layer. JP-A-52-105821, No. 52-
105822, 56-50328, and U.S. Pat. No. 4,235,957, etc., methods for obtaining positive dye images by silver dye bleaching methods, as well as U.S. Pat. No. 3,180,731,
Same No. 3985565, Same No. 4022617, Same No. 4452883,
Various methods have been proposed, such as the method of obtaining a dye image using a leuco dye disclosed in Japanese Patent Application Laid-Open No. 59-206831. However, with these proposals regarding the heat-developable color photosensitive materials, it is difficult to bleach and fix the black, white, and silver images formed at the same time, and
It is difficult to obtain clear color images,
Furthermore, it required complicated post-processing, and was not yet satisfactory for practical use. In recent years, as a new type of color image forming method using heat development, Japanese Patent Laid-Open Nos. 57-179840 and 57-
No. 186744, No. 57-198458, No. 57-207250, etc. disclose methods for obtaining color images by transferring diffusible dyes released by heat development. These methods were further improved to produce diffusible dyes by oxidizing non-diffusible reducing dye-donating substances, such as those disclosed in JP-A-58-58453 and JP-A-59-168439. A method of emitting
JP-A No. 58-79247, No. 59-174834, No. 59-
12431, No. 59-159159, No. 60-2950, etc., in which a non-diffusible reducing dye donor substance and an oxidized developing agent are coupled to release a diffusible dye. , Japanese Patent Publication No. 1983-
No. 149046, No. 58-149047, No. 59-124339, No.
No. 59-181345, No. 60-2950, Patent Application No. 1987-181604
No. 59-182506, No. 59-182507, No. 59-
272335, etc., which uses a non-diffusible compound that reacts with the oxidized form of a developing agent to form a diffusible dye;
No. 59-124327, No. 59-154445, No. 59-
166954, etc., non-diffusible reducing dye-donating substances that lose their ability to release diffusible dyes upon oxidation;
Conversely, a method containing a non-diffusible dye-donating substance that releases a diffusible dye upon reduction;
etc. have been proposed. The above-mentioned heat-developable photosensitive material obtains a color image by transferring the released or formed diffusible dye onto the image-receiving layer of an image-receiving element provided on the same support or another independent support. In terms of image sharpness, stability, etc., it has been improved in many respects compared to previous heat-developable color photosensitive materials. The basic composition of a color type heat-developable photosensitive material that produces a color image using these emitted or formed diffusive dyes consists of a light-sensitive element and an image-receiving element. It consists of a silver salt, a reducing agent, a dye-providing substance, and a binder. In the present invention, only the photosensitive element is referred to as a heat-developable photosensitive material in a narrow sense, and the image receiving element is referred to as an image receiving member. It has been proposed to add an acid or an acid precursor to such a photothermographic material to obtain a high contrast image (increase the maximum density and lower the minimum density). For example, JP-A-60-108837, JP-A No. 60-192939,
No. 60-230133, No. 60-230134, etc. disclose heat-developable photosensitive materials using acids or acid precursors. However, since these acid precursors release acid through thermal decomposition during thermal development, it is difficult to store the photothermographic materials containing the acid precursors unused for a long period of time (hereinafter referred to as raw storage). In this case, the acid precursor gradually releases acid, resulting in a blurred image with low contrast. In addition, in heat-developable photosensitive materials using acids,
There was a drawback that the acid diffused in the photosensitive layer during raw storage, resulting in a blurred image with low contrast. [Object of the Invention] Therefore, an object of the present invention is to provide a heat-developable photosensitive material that has excellent shelf life and can provide images with high contrast. [Structure of the Invention] An object of the present invention is to provide a heat-developable photosensitive material having at least a photosensitive silver halide, a dye donor, a reducing agent, a binder, and microcapsules on a support. This was achieved by containing at least one of the following: and an acid precursor. [Specific Structure of the Invention] The acid or acid precursor used by being contained in the core material of the microcapsule of the present invention will be explained. In the present invention, either inorganic or organic acids can be preferably used as the acid. Inorganic acids include sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid,
Boric acid, metaboric acid, etc. can be used. As the organic acid, aliphatic carboxylic acids, aromatic carboxylic acids, aliphatic sulfonic acids, aromatic sulfonic acids, aliphatic monosulfuric esters, and aromatic monosulfuric esters can be used. Further, the organic acid may be a high molecular compound, that is, a polymeric acid. Polymer acids are also preferably used as acids, and examples of such polymer acids include homopolymers of unsaturated organic acid monomers and copolymers of unsaturated organic acid monomers and other vinyl monomers. Examples of unsaturated organic acid monomers include acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, and crotonic acid. Further, phosphonic acid, sulfonic acid, etc. having a vinyl group, and acid anhydrides such as maleic anhydride can also be used. There are no particular restrictions on the vinyl monomers that can be copolymerized with the unsaturated organic acid monomers, but examples include acrylic esters such as methyl acrylate, ethyl acrylate, and butyl acrylate, styrenes,
Examples include acrylonitriles, vinyl chlorides, vinylidene chlorides, divinylbenzenes, and the like. Furthermore, when synthesizing polymer acids, it is not always necessary to use organic acid monomers with vinyl groups as raw materials; for example, it is also possible to react with sulfuric acid to the hydroxyl groups in the polymer to form monosulfate esters. be. Specific examples of the polymer acids used in the present invention are described below, but the present invention is not limited thereto.

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[Formula] Other preferred acids include, but are not limited to, the following low molecular weight organic acids. (A-1) HOOC (CH ₂ ) 〓 COOH where n = 0 (A-2) HOOC (CH ₂ ) 〓 COOH where n = 1 (A-3) HOOC (CH ₂ ) 〓 COOH where n = 2 (A -4) HOOC (CH ₂ ) = COOH where n = 4 (A-5) HOOC (CH ₂ ) = COOH where n = 6 (A-6) HOOC (CH ₂ ) = COOH where n = 8 (A-7 ) HOOC (CH ₂ ) 〓COOH where n=10

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[Formula] (A-26) CH ₃ (CH ₂ )〓COOH where n=8 (A-27) CH ₃ (CH ₂ )〓COOH where n=10 (A-28) CH ₃ (CH ₂ )〓COOH However, n=12 (A-29) CH ₃ (CH ₂ )〓COOH However, n=14 (A-30) CH ₃ (CH ₂ )〓COOH However, n=16 (A-31) CH ₃ (CH ₂ )〓 COOH However, n=18 (A-32) CH ₃ (CH ₂ )〓COOH However, n=22

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[Formula] In the present invention, acid precursors are preferably used among acids and acid precursors. Acid precursors are compounds that release acidic substances when heated. As a preferable acid precursor, JP-A 1987-1999-
No. 108837 and JP-A No. 60-192939, hydroxamic carboxylates that release acid through lotusene rearrangement;
Aldoxime carboxylates which generate nitrile and release acid at the same time as disclosed in JP-A-60-230133 can be used. One of the effective acid precursors is a compound having a partial structure represented by the following general formula []. However, the bonds at both ends of the partial structure [ ] are bonded to carbon atoms.

[Formula] Among the acid precursors having a partial structure represented by the above general formula [], those which can be particularly advantageously used in the present invention are compounds represented by the following general formula [].

[Chemical formula] In the formula, R ₁ is an alkyl group, a cycloalkyl group,
Represents an alkenyl group, an aryl group or a heterocyclic group. _n1 represents an integer from 1 to 3. R ₁ is n ₁ is 1
represents an alkyl group, cycloalkyl group, aryl group or heterocyclic group, and when n ₁ is 2 to 3, each represents 2 to 3 derived from an alkyl group, cycloalkyl group, aryl group or heterocyclic group, respectively.
represents a group having a bond. The alkyl group represented by R ₁ and R ₂ is
Can be straight chain or branched, preferably has 1 to 18 carbon atoms
This alkyl group includes those having substituents. Examples of substituents for alkyl groups include halogen atoms, aryl groups, alkoxy groups, cyano groups, optionally substituted carbamoyl groups, hydroxyl groups, and carboxy groups. _R1 and _R2
Specific examples of the alkyl group represented by include methyl group, ethyl group, propyl group, butyl group,
Examples include hexyl group, decyl group, dodecyl group, and benzyl group. The cycloalkyl group represented by R ₁ and R ₂ is preferably a 5- or 6-membered cycloalkyl group having 5 to 10 carbon atoms, and this cycloalkyl group includes those having a substituent. , and the same groups as those mentioned above for the alkyl group. Examples of the cycloalkyl group represented by R ₁ and R ₂ include a cyclopentyl group and a cyclohexyl group. The alkenyl group represented by R ₁ includes those having a substituent, and examples of the substituent include the same groups as mentioned above for the alkyl group.
Examples of the alkenyl group represented by R ₁ include a vinyl group, an allyl group, and a styryl group. The aryl group represented by R ₁ and R ₂ is
Aryl groups having 6 to 18 carbon atoms are preferred, such as phenyl, naphthyl, anthryl, and the like, including those having substituents. Examples of substituents for aryl groups include alkyl groups, aryl groups, halogen atoms, alkoxy groups,
Aryloxy group, hydroxyl group, mercapto group, amino group, acylamino group, sulfonylamino group, cyano group, nitro group, alkylthio group, arylthio group, alkylsulfonyl group, arylsulfonyl group, alkyloxycarbonyl group, aryloxycarbonyl group, acyloxy substituent groups, sulfamoyl groups, carbamoyl groups, and combinations of these groups, and when there are two or more substituents, these may be the same or different. Examples of the heterocyclic residue represented by R ₁ and R ₂ include a pyridyl group, a furyl group, a thienyl group, a pyrrole group, and an isodoryl group. Also,
This heterocyclic residue may have the same substituents as those mentioned for the aryl group above. R ₁ is preferably an aryl group, a substituted aryl group, or a heterocyclic residue, among which a phenyl group,
More preferred are substituted phenyl groups, naphthyl groups, and substituted naphthyl groups. _R2 is preferably an aryl group, a substituted aryl group, or a heterocyclic residue, among which a phenyl group,
More preferred are substituted phenyl groups, naphthyl groups, and substituted naphthyl groups. These compounds release or form acids at temperatures necessary for thermal development, but the reaction rate is R ₁
and R ₂ can be varied over a wide range. Another example of an effective acid precursor is a compound having a partial structure represented by the following general formula []. However, the bonds at both ends of the partial structure of general formula [ ] are bonded to carbon atoms.

embedded image Among the acid precursors having a partial structure represented by the above general formula [], compounds represented by the following general formula [] can be particularly advantageously used in the present invention.

embedded image In the formula, R ₃ , R ₄ and n ₂ have the same meanings as R ₁ , R ₂ and n ₁ shown in the general formula [], respectively. These compounds also release or form acid at temperatures necessary for thermal development, but the reaction rate can be varied over a wide range by varying R ₃ and R ₄ . Specific examples of acid precursors advantageously used in the present invention are shown below. However, it is not limited to these.

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[C] In addition to the acids mentioned above, JP-A-49-
Described in No. 58642, JP-A No. 50-57452, etc.
Acidic components that dissolve or release volatile acids above 60°C can be used. The acid or acid precursor-containing microcapsules used in the present invention may be added to any layer of the heat-developable photosensitive material and the image-receiving member, such as the photosensitive layer, undercoat layer, intermediate layer, protective layer, image-receiving layer, etc. Although it can be added to the photosensitive layer, it is preferable to add it to the photosensitive layer. At this time, the photosensitive layer and the image-receiving layer may be on separate supports or on the same support. The amount of microcapsules containing the acid or acid precursor used in the present invention varies depending on the acid or acid precursor used, but is usually 0.01 to 20 g per 1 m ² of the photothermographic material in terms of acid or acid precursor amount. , preferably 0.05 to 10 g. The acid or acid precursor according to the present invention is
They may be used alone or in combination of two or more. Microcapsules containing an acid or an acid precursor in the core material used in the present invention will be explained. In the present invention, the microcapsule containing an acid or an acid precursor in its core material only needs to have the function of releasing the core material when a predetermined amount of heat is applied. That is, these functions are provided by the following method. (a) A method of adding a thermally expandable substance to the core material as described in JP-A-56-119136; (b) A widely known method of adding a thermally expandable substance to the core material as a wall material. (c) A method of coating a porous outer wall with a liquid crystal material and displacing it by heat, as described in Okahata, Huain Chemical, Vol. 13, p. 27 (1984), etc. be. Specific examples of each of (a), (b), and (c) include the following compounds. In the case of (a), cellulose, gelatin, gum arabic, acrylic resin, styrene resin, polyester resin, urethane resin, polyamide resin, epoxy resin, vinyl alcohol resin, etc. are used as the wall material. In addition, thermally expandable substances added to the core material include compounds that decompose with heat and release nitrogen such as azobisisobutyronitrile and azobisisovaleronitrile, nitro-containing compounds such as trinitrotoluene and picric acid, Volatile substances such as isobutylene and butane are used. In the case of (b), a polymeric material that melts at a temperature below the heat development temperature is used as the wall material. For example, styrene resins such as polystyrene and polychlorostyrene, acrylic resins such as polymethyl methacrylate, polymethyl acrylate, polyethyl acrylate, polybutyl methacrylate, thermoplastic resins such as polyester resins, polyethylene, polyoxyethylene, higher fatty acid amides, higher grade fatty acid ester,
Waxes such as carnauba wax and beeswax are used. In the case of (c), examples of the porous outer wall include nylon obtained by interfacial polymerization, and examples of the liquid crystal material include the following bilayer membranes. () [CH ₃ (−CH ₂ )− ₁₁ ] ₂ PO ₄ Na

[Chemical] () [CH ₃ (−CH ₂ ) ₁₃ −−] ₂ −−N(CH ₃ ) ₃ Br

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[ ] Also, in such microcapsules, the particle size is
It is 5 μm or less, preferably 1 μm or less. Various encapsulation methods can be applied as a method for producing microcapsules containing an acid or an acid precursor in the core material used in the present invention. For example, US Patent No. 2800457, US Patent No. 2800458,
Same No. 3287154, No. 3418250, No. 3660304, Same No.
One of the methods shown in No. 3726804, No. 3796669, British Patent No. 990443 and Japanese Patent Application Laid-Open No. 113434/1986 can be used. In the present invention, a method for producing microcapsules having an average particle size of 1 μm or less is particularly desirable, but such production methods can be broadly classified into the following two types. One is interfacial polymerization using emulsification such as electroemulsification, and the other is so-called micelle polymerization, in which polymerization is performed after forming micelles. It is not possible to use both methods for all core materials when encapsulating core materials containing acids or acid precursors. That is, in the interfacial polymerization method, for example, it is impossible to use a core material that easily reacts with acid chlorides, and in the micelle polymerization method, a core material that prevents radical reactions cannot be used. The method for producing microcapsules is described by G. Bielenbach and P.P. Spicer (G.
Birrenback, PPSpeiser), Journal of Pharmaceutical Sciences
of Pharmaceutical Sciences), 65(12) p.1763
~1766 (1976), P. Tulkens, M. Roland, A. Trouet, P. Trouet, P.
Micelle polymerization method by P. Speiser et al., described in FEBS Letters, 84 (2) p. 323 (1977), Watanabe, Higashitsuji, Nishizawa (A. Watanabe, K. .Higashitsuji, K.
Nishizawa), Journal of Colloid and Interface Science (Journal of Colloid and Interface Science)
of Colloid and Interface Science), 64(2)
p.278 (1978), Arakawa, Kondo (M.Arakawa, T.
Canadian Journal of Physiology and Pharmacology
The interfacial polymerization method by electroemulsification described in Pharmacology, 58(2) p. 183 (1980), etc. are advantageously used. When the heat-developable photosensitive material of the present invention is a color type, a dye-providing substance is used. Dye-providing substances that can be used in the present invention will be explained below. The dye-donating substance may be any substance as long as it participates in the reduction reaction of the photosensitive silver halide and/or the organic silver salt used as necessary and can form or release a diffusible dye as a function of the reaction. Depending on its reaction form, negative-acting dye-donors that act in a positive function (i.e.
A positive dye-donor acting on a negative function (i.e., a positive dye image when using a negative-working silver halide) ) can be classified as Negative dye-donating substances are further classified as follows.

[Table] Cut-off ring color Cut-off ring color
Elementary-emitting compounds Elementary-forming compounds
Each dye-providing substance will be further explained. As the reducing dye releasing compound, for example, the general formula
Examples include compounds represented by (2). General formula (2) Car−NHSO ₂ −Dye In the formula, Car is a reducing substrate (so-called carrier) that is oxidized and releases a dye upon reduction of photosensitive silver halide and/or organic silver salt used as necessary. ), and Dye is a diffusible dye residue. Specific examples of the above-mentioned reducing dye-releasing compounds include JP-A-57-179840, JP-A-58-116537, and JP-A-59.
−60434, No. 59-65839, No. 59-71046, No.
No. 59-87450, No. 59-88730, No. 59-123837,
They are described in the specifications of No. 59-165054 and No. 59-165055, and include, for example, the following compounds. Exemplary dye-donor substances

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embedded image Another reducible dye-releasing compound includes, for example, a compound represented by the general formula (3).

[Chemical formula] In the formula, A ₁ and A ₂ each represent a hydrogen atom, a hydroxy group, or an amino group, and Dye is represented by the general formula (2).
Synonymous with dye. Specific examples of the above compounds are given in JP-A-Sho.
No. 59-124329. Examples of the coupling dye-releasing compound include compounds represented by general formula (4). General formula (4) Cp ₁ (-J) _o1 Dye In the formula, Cp ₁ is an organic group (so-called coupler residue) that can react with the oxidized form of the reducing agent to release a diffusible dye, and J is a divalent bonding group, and the bond between Cp ₁ and J is cleaved by reaction with the oxidized form of the reducing agent. n ₁ represents 0 or 1, and Dye has the same meaning as defined in general formula (2). Also
Cp ₁ is preferably substituted with various ballast groups in order to make the coupling dye-releasing compound non-diffusible, and the ballast group has 8 or more carbon atoms (or more) depending on the form of the photosensitive material used. (preferably 12 or more) organic groups or sulfo groups,
Hydrophilic groups such as carboxy groups, or 8 or more (more preferably 12 or more) carbon atoms and sulfo groups,
It is a group that also has a hydrophilic group such as a carboxy group. Another particularly preferred ballast group can include polymer chains. Specific examples of the compound represented by the above general formula (4) include JP-A-57-186744, JP-A-57-122596, and JP-A-57-122596;
No. 57-160698, No. 59-174834, No. 57-224883
No. 59-159159 and No. 59-231540, examples of which include the following compounds. Exemplary dye-donor substances

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[Chemical formula] Examples of the coupling dye-forming compound include compounds represented by the general formula (5). General formula (5) Cp ₂ (-F)-(-B) In the formula, Cp ₂ is an organic group (so-called coupler) that can react with the oxidized form of the reducing agent (coupling reaction) to form a diffusible dye. residue), and F
represents a divalent bonding group, and B represents a ballast group. The coupler residue represented by Cp ₂ preferably has a molecular weight of 700 or less, more preferably 500 or less, in view of the diffusibility of the dye formed. In addition, the ballast group is preferably the same as the ballast group defined in general formula (4), and particularly has 8 or more (more preferably 12 or more) carbon atoms and a hydrophilic group such as a sulfo group or a carboxy group. Groups having both are preferred, and polymer chains are more preferred. The coupling dye-forming compound having a polymer chain is preferably a polymer having a repeating unit derived from a monomer represented by general formula (6). General formula (6) Cp ₂ (-F)-(-Y) _l --(-Z)-(-L) In the formula, Cp ₂ and F have the same meaning as defined in general formula (5). , Y represents an alkylene group, arylene group, or aralkylene group, l represents 0 or 1, Z represents a divalent organic group, and L represents an ethylenically unsaturated group or a group having an ethylenically unsaturated group. . Specific examples of coupling dye-forming compounds represented by general formulas (5) and (6) include JP-A-59-
No. 124339, No. 59-181345, No. 60-2950, Patent Application No. 179-179657, No. 59-181604, No. 59-182506
No. 59-182507, for example, the following compounds are mentioned. Exemplary dye-donor substances

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[C] In the above general formulas (4), (5) and (6), Cp ₁ or
More specifically, the coupler residue defined by Cp ₂ is preferably a group represented by the following general formula.

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[Formula] In the formula, R ⁷ , R ⁸ , R ⁹ and R ¹⁰ are each a hydrogen atom, a halogen atom, an alkyl group, a cycloalkyl group, an aryl group, an acyl group, an alkyloxycarbonyl group, an aryloxycarbonyl group, and an alkylsulfonyl group. group, arylsulfonyl group, carbamoyl group, sulfamoyl group, acyloxy group,
Represents an amino group, an alkoxy group, an aryloxy group, a cyano group, an alkylsulfonyl group, an arylsulfonyl group, a ureido group, an alkylthio group, an arylthio group, a carboxy group, a sulfo group, or a heterocyclic residue, which can further be a hydroxyl group, a carboxy group , a sulfo group, an alkoxy group, a cyano group, a nitro group, an alkyl group, an aryl group, an aryloxy group, an acyloxy group, an acyl group, a sulfamoyl group, a carbamoyl group, an imide group, a halogen atom, or the like. These substituents are selected depending on the purpose of Cp ₁ and Cp ₂ , and as mentioned above, in Cp ₁ , one of the substituents is preferably a ballast group, and in Cp ₂ , it is preferable that one of the substituents is a ballast group. In order to increase the molecular weight, the substituents are preferably selected so that the molecular weight is 700 or less, more preferably 500 or less. Examples of positive dye-donating substances include oxidizable dye-releasing compounds represented by the following general formula (17).

[Chemical formula] In the formula, W ₁ represents a collection of atoms necessary to form a quinone ring (which may have a substituent on this ring), R ¹¹ represents an alkyl group or a hydrogen atom, E is

[Formula] (In the formula, R ¹² represents an alkyl group or a hydrogen atom, and R ¹³ represents an oxygen atom or

Represents [formula]. ) or _-SO2- , r represents 0 or 1, and Dye has the same meaning as defined in general formula (2). Specific examples of this compound are described in the specifications of JP-A-59-166954 and JP-A-59-154445, and include the following compounds. Exemplary dye-donor substances

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[Chemical Formula] Another positive dye-donating substance is a compound represented by the following general formula (18), which loses its dye-releasing ability when oxidized.

[Formula] In the formula, W ₂ represents a group of atoms necessary to form a benzene ring (which may have a substituent on the ring), and R ¹¹ , r, E, and Dye represent the general formula (17 ) has the same meaning as defined in ). Specific examples of this compound are described in the specifications of JP-A-59-124327 and JP-A-59-152440, and include the following compounds. Exemplary dye-donor substances

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[Chemical Formula] Still another positive dye-providing substance includes a compound represented by the following general formula (19).

[Formula] In the above formula, W ₂ , R ¹¹ and Dye are general formula (18)
It has the same meaning as defined in . Specific examples of this compound are described in JP-A-59-154445, etc., and include the following compounds. Exemplary dye-donor substances

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[Image Omitted] The residues of the diffusible dyes represented by Dye in the above general formulas (2), (3), (4), (17), (18) and (19) will be described in further detail. Due to the diffusivity of the dye, the residue of the diffusible dye has a molecular weight of 800 or less,
More preferably, it is 600 or less,
Examples include residues of azo dyes, azomethine dyes, anthraquinone dyes, naphthoquinone dyes, styryl dyes, nitro dyes, quinoline dyes, carbonyl dyes, phthalocyanine dyes, and the like. These dye residues may be in a temporary short-waveform form that allows multiple colors during thermal development or transfer. In addition, these dye residues are used for the purpose of increasing the light resistance of images, for example, in
The chelatable dye residues described in No. 48765 and No. 59-124337 are also preferred. These dye-providing substances may be used alone or in combination of two or more. The amount used is not limited, and depends on the type of dye-providing substance, whether it is used alone or in combination, or whether the photographic constituent layer of the light-sensitive material of the present invention is a single layer or a multilayer of two or more types. You can decide accordingly, but for example, the usage amount is 1 m ²
It can be used in an amount of 0.005g to 50g, preferably 0.1g to 10g. Any method can be used to incorporate the dye-providing substance used in the present invention into the photographic constituent layer of the heat-developable photosensitive material.
For example, after dissolving in a low boiling point solvent (methanol, ethanol, ethyl acetate, etc.) or a high boiling point solvent (dibutyl phthalate, dioctyl phthalate, tricresyl phosphate, etc.), ultrasonic dispersion,
Alternatively, after dissolving in an alkaline aqueous solution (e.g., 10% aqueous sodium hydroxide solution, etc.), it can be used by neutralizing it with a mineral acid (e.g., hydrochloric acid or nitric acid, etc.);
Alternatively, it can be used after being dispersed with a suitable polymer aqueous solution (eg, gelatin, polyvinyl butyral, polyvinyl pyrrolidone, etc.) using a ball mill. Examples of the photosensitive silver halide used in the present invention include silver chloride, silver bromide, silver iodide, silver chlorobromide, silver chloroiodide, silver iodobromide, and silver chloroiodobromide. The photosensitive silver halide can be prepared by any method used in the photographic field, such as a single jet method or a double jet method. For example, JP-A-54-48521
By applying the method described in the above publication, monodisperse silver halide grains can be obtained by a double jet method while keeping pAg constant. At that time, a highly monodisperse silver halide emulsion can be obtained by appropriately selecting the time function of addition rate, PH, pAg, temperature, etc. According to a further preferred embodiment, silver halide emulsions having silver halide grains with shells can be used. Silver halide grains having shells can be obtained by sequentially growing shells on a core of silver halide grains having good monodispersity using the method described above. The monodisperse silver halide emulsion referred to in the present invention is
An emulsion having a particle size distribution in which the variation in size of silver halide grains contained in the emulsion is not more than a certain ratio with respect to the average grain size as shown below.
Since the grain size distribution of an emulsion (hereinafter referred to as a monodisperse emulsion) consisting of a group of photosensitive silver halide grains with a uniform grain morphology and small variation in grain size is almost a normal distribution, the standard deviation can be easily determined. When the width of the distribution is defined by the relational expression standard deviation/average particle size x 100 = width of distribution (%), the width of the distribution of the silver halide grains used in the present invention is 15% or less. is preferable, and more preferably has a monodispersity of 10% or less. Also, for example, JP-A-58-111933, JP-A No. 58-111933;
As described in No. 111934, No. 58-108526, Research Disclosure No. 22534, etc.
A particle that has two parallel crystal planes, and each of these crystal planes has a larger area than other single crystals of this particle, and its aspect ratio, that is,
Silver halide emulsions comprising tabular silver halide grains having a grain diameter to thickness ratio of 5:1 or more can also be used. Further, in the present invention, a silver halide emulsion containing internal latent image type silver halide grains whose surfaces have not been fogged in advance can be used. Regarding internal latent image type silver halide whose surface is not fogged in advance, for example, US Pat. No. 2,592,250, US Pat.
No. 3317322, No. 3511662, No. 3447927,
As described in No. 3761266, No. 3703584, No. 3736140, etc., it is a silver halide grain in which the sensitivity inside the grain is higher than the sensitivity on the surface of the grain. The method for producing silver halide emulsions containing these internal latent image type silver halides is as described in the above-mentioned patent, for example, by first preparing AgCl grains and then adding bromide or a small amount of iodide thereto. A method in which a central core of chemically sensitized silver halide is coated with non-chemically sensitized silver halide, or a chemically sensitized coarse grain emulsion and a chemically sensitized coarse grain emulsion are used. Alternatively, many methods are known, such as a method in which a fine grain emulsion that is not chemically sensitized is mixed and the fine grain emulsion is deposited on a coarse grain emulsion. Also, U.S. Patent No. 3,271,157,
Silver halide emulsions having silver halide grains containing multivalent metal ions as described in U.S. Pat. No. 3,447,927 and U.S. Pat. Silver halide emulsions in which the grain surfaces of silver halide grains are weakly chemically sensitized, or silver halide emulsions consisting of grains having a layered structure as described in JP-A-50-8524 and JP-A-50-38525, etc. Other examples include silver halide emulsions described in JP-A-52-156614 and JP-A-55-127,549. The light-sensitive silver halide emulsion may be chemically sensitized by any method known in the photographic art. Such sensitization methods include various methods such as gold sensitization, sulfur sensitization, gold-sulfur sensitization, and reduction sensitization. The silver halide in the above-mentioned photosensitive emulsion may be coarse grains or fine grains, but the preferred grain size is about 0.001 μm to about 1.5 μm,
More preferably, it is about 0.01 μm to about 0.5 μm. The photosensitive silver halide emulsion prepared as described above can most preferably be applied to the heat-developable photosensitive layer which is a constituent layer of the photosensitive material of the present invention. In the present invention, as another method for preparing photosensitive silver halide, it is also possible to allow a photosensitive silver salt-forming component to coexist with an organic silver salt described below to form photosensitive silver halide in a part of the organic silver salt. . The photosensitive silver salt-forming component used in this preparation method is an inorganic halide, for example, a halide represented by MXn (where M represents an H atom, an _NH4 group, or a metal atom, and X represents Cl, Br). or represents I,
n indicates 1 when M is an H atom or an NH ₄ group, and indicates the valence when M is a metal atom. As a metal atom,
Lithium, sodium, potassium, rubidium,
cesium, copper, gold, beryllium, magnesium,
Calcium, strontium, barium, zinc,
cadmium, mercury, aluminum, indium,
Lanthanum, ruthenium, thallium, germanium, tin, lead, antimony, bismuth, chromium, molybdenum, tungsten, manganese, rhenium,
Examples include iron, cobalt, nickel, rhodium, palladium, sumium, iridium, platinum, and cerium. ), halogen-containing metal complexes (e.g.
K ₂ PtCl ₆ , K ₂ PtBr ₆ , HAuCl ₄ , (NH ₄ ) ₂ IrCl ₆ ,
(NH ₄ ) ₃ IrCl ₆ , (NH ₄ ) ₂ RuCl ₆ , (NH ₄ ) ₃ RuCl ₆ ,
(NH ₄ ) ₂ RhCl ₆ , (NH ₄ ) ₃ RhBr ₆ , etc.), onium halides (e.g., tetramethylammonium bromide, trimethylphenylammonium bromide, cetylethyldimethylammonium bromide, 3-methylthiazolium bromide, trimethylbenzyl quaternary ammonium halides such as ammonium bromide, quaternary phosphonium halides such as tetraethyl phosphonium bromide, tertiary sulfonium halides such as benzylethylmethylsulfonium bromide, 1-ethylthiazolium bromide, etc.), halogenation Hydrocarbons (e.g. iodoform, bromoform, carbon tetrabromide, 2-bromo-2-methylpropane, etc.), N-halogen compounds (N-chlorosuccinimide, N-bromosuccinimide, N-
Bromophthalic acid imide, N-bromoacetamide, N-iodosuccinimide, N-bromophthalazinone, N-chlorophthalazinone, N-bromoacetanilide, N,N-dibromobenzenesulfonamide, N-bromo-N-methylbenzene sulfonamide, 1,3-dibromo-4,4-dimethylhydantoin, etc.), and other halogen-containing compounds (e.g., triphenylmethyl chloride, triphenylmethyl bromide, 2-bromobutyric acid, 2-bromoethanol, etc.). be able to. These photosensitive silver halides and photosensitive silver salt-forming components can be used in combination in various methods, and the amounts used are as ^follows :
The amount is preferably 0.001 g to 50 g, more preferably 0.1 g to 10 g. The heat-developable photosensitive material of the present invention has blue light, green light,
It is also possible to have a multilayer structure including each layer having sensitivity to red light, that is, a heat-developable blue-sensitive layer, a heat-developable green-sensitive layer, and a heat-developable red-sensitive layer. In addition, two or more photosensitive layers of the same color (for example, a high-sensitivity layer and a low-sensitivity layer)
It can also be divided into two parts. In the above cases, the blue-sensitive silver halide emulsion, green-sensitive silver halide emulsion, and red-sensitive silver halide emulsion used, respectively, are prepared by adding various spectral sensitizing dyes to the silver halide emulsion. Obtainable. Typical spectral sensitizing dyes used in the present invention include, for example, cyanine, merocyanine, complex (trinuclear or tetranuclear) cyanine, holopolar cyanine, styryl, hemicyanine, oxonol, and the like. Among the cyanine pigments, thiazoline, oxazoline, pyrroline, pyridine, oxazole, thiazole, selenazole,
Those having a basic core such as imidazole are more preferred. Such a nucleus may contain an alkyl group, an alkylene group, a hydroxyalkyl group, a sulfoalkyl group, a carboxyalkyl group, an aminoalkyl group, or an enamine group capable of forming a fused carbocyclic or heterocyclic ring. good. Further, it may be symmetrical or asymmetrical, and the methine chain or polymethine chain may have an alkyl group, phenyl group, enamine group, or heterocyclic substituent. In addition to the above-mentioned basic nucleus, merocyanine dyes have acidic nuclei such as thiohydantoin nucleus, rhodanine nucleus, oxazolidione nucleus, thiazolidinedione nucleus, barbituric acid nucleus, thiazolinthione nucleus, malononitrile nucleus, and pyrazolone nucleus. Good too. These acidic nuclei may be further substituted with an alkyl group, an alkylene group, a phenyl group, a carboxyalkyl group, a sulfoalkyl group, a hydroxyalkyl group, an alkoxyalkyl group, an alkylamine group or a heterocyclic nucleus. If necessary, these dyes may be used in combination. Furthermore, ascorbic acid derivatives, azaindene cadmium salts, organic sulfonic acids, etc., such as US Pat. No. 2,933,390,
A supersensitizing additive that does not absorb visible light, such as those described in the specification of No. 2937089, can be used in combination. The amount of these sensitizing dyes added is 1×10 ^-4 per mole of photosensitive silver halide or silver halide forming component.
mol to 1 mol. More preferably, 1×10 ⁻⁴
mole to 1×10 ⁻¹ mole. In the heat-developable photosensitive material of the present invention, various organic silver salts can be used, if necessary, for the purpose of increasing sensitivity and improving developability. Examples of organic silver salts used in the heat-developable photosensitive material of the present invention include Japanese Patent Publication No. 43-4921 and Japanese Patent Application Laid-Open No. 49-52626.
No. 52-141222, No. 53-36224 and No. 53
Publications such as −37610 and U.S. Patent No. 3330633
Silver salts of long-chain aliphatic carboxylic acids and silver salts of carboxylic acids having a heterocycle as described in the specifications of No. 3794496, No. 4105451, etc.
For example, silver laurate, silver myristate, silver palmitate, silver stearate, silver arachidonate, silver behenate, α-(1-phenyltetrazolthio)
Silver aromatic carboxylates such as silver acetate, such as silver benzoate, silver phthalate, etc.,
No. 45-12700, No. 45-18416, No. 45-22185,
JP-A-52-137321, JP-A-58-118638, JP-A-58
There are silver salts of imino groups described in publications such as No. 118639 and US Pat. No. 4,123,274. Examples of silver salts of imino groups include benztriazole silver. The benztriazole silver may be substituted or unsubstituted. Representative examples of silver substituted benztriazoles include:
For example, alkyl-substituted benztriazole silver (preferably substituted with a _C22 or less alkyl group, more preferably a _C4 or less alkyl group, such as methylbenztriazole silver, ethylbenztriazole silver, n-octylbenztriazole silver, etc.) ), silver alkylamidobenztriazole (preferably substituted with an alkylamide group of up to _C22 , e.g. silver acetamidobenztriazole, silver propionamidobenztriazole, silver iso-butylamidobenztriazole,
silver laurylamide benztriazole, etc.), silver alkylsulfamoylbenztriazole (preferably substituted with an alkylsulfamoyl group of C ₂₂ or less, for example, silver 4-(N,N-diethylsulfamoyl)benztriazole) , 4-
(N-propylsulfamoyl)benztriazole silver, 4-(N-octylsulfamoyl)benztriazole silver, 4-(N-decylsulfamoyl)benztriazole silver, 5-(N-octylsulfamoyl) benztriazole silver, etc.),
Silver salts of halogen-substituted benztriazoles (for example, silver 5-chlorobenztriazole, silver 5-bromobenztriazole, etc.), silver alkoxybenztriazole (preferably an alkoxy group of C ₂₂ or less, more preferably an alkoxy group of C ₄ or less) silver 5-methoxybenztriazole, silver 5-ethoxybenztriazole, etc.), silver 5-nitrobenztriazole, silver 5-aminobenztriazole, silver 4-hydroxybenztriazole, silver 5-carboxybenztriazole, 4-Sulfobenztriazole silver, 5
-silver sulfobenztriazole, and the like. Examples of other imino group-containing silver salts include imidazole silver, benzimidazole silver, 6
- nitrobenzimidazole silver, pyrazole silver,
urazole silver, 1,2,4-triazole silver,
Silver salts of other mercapto compounds such as 1H-tetrazole silver, 3-amino-5-benzylthio-1,2,4-triazole silver, satucalin silver, phthalazinone silver, phthalimide silver, etc., such as 2-mercaptobenzoxazole silver, mercaptooxadi Azole silver, 2-mercaptobenzothiazole silver, 2-mercaptobenzimidazole silver, 3-
Mercapto-4-phenyl-1,2,4-triazole silver, 4-hydroxy-6-methyl-1,
Examples include 3,3a,7-tetrazaindene silver and 5-methyl-7-hydroxy-1,2,3,4,6-pentazaindene silver. In addition, a silver complex compound having a stability constant of 4.5 to 10.0 as described in JP-A-52-31728, a silver salt of imidazolinthion as described in US Pat. No. 4,168,980, and the like can be used. Among the above organic silver salts, imino group silver salts are preferable, particularly silver salts of benzotriazole derivatives,
More preferred are 5-methylbenzotriazole and its derivatives, sulfobenzotriazole and its derivatives, and N-alkylsulfamoylbenzotriazole and its derivatives. The organic silver salts used in the present invention may be used alone or in combination of two or more. Further, a silver salt may be prepared in a suitable binder and used as it is without isolation, or the isolated salt may be dispersed in a binder by an appropriate means and used. Dispersion methods include, but are not limited to, ball mills, sand mills, colloid mills, vibration mills, and the like. In addition, the method for preparing organic silver salts is generally to dissolve silver nitrate and raw organic compounds in water or an organic solvent and mix them, but if necessary, a binder may be added or a solution such as sodium hydroxide may be added. Adding alkali to promote the dissolution of organic compounds,
It is also effective to use an ammoniacal silver nitrate solution. The amount of the organic silver salt used is generally preferably 0.01 to 500 mol, more preferably 0.1 to 100 mol, per 1 mol of photosensitive silver halide. More preferably, it is 0.3 to 30 mol. As the reducing agent used in the photothermographic material of the present invention, those commonly used in the field of photothermographic materials can be used. The dye-providing substance used in the heat-developable photosensitive material of the present invention is, for example, JP-A-57-186744;
No. 58-79247, No. 58-149046, No. 58-149047
No. 59-124339, No. 59-181345, No. 60-
In the case of a dye-donating substance that releases or forms a diffusible dye by coupling with an oxidized form of a reducing agent such as that disclosed in No. 2950, it may be used as a reducing agent in the present invention. For example, US Pat. No. 3,531,286, US Pat. No. 3,761,270,
3764328 specifications, RD No. 12146, and the same No.
15108, No. 15127 and JP-A-56-27132, p-phenylenediamine type and p-aminophenol type developing agents, phosfluoramide phenol type, sulfonamide phenol type developing agents, sulfonamide aniline type developing agents A developing agent, a hydrazone color developing agent, etc. can be used. Also, U.S. Patent No. 3342599, U.S. Patent No. 3719492
Color developing agent precursors described in Japanese Patent Application Laid-open Nos. 53-135628 and 57-79035 can also be advantageously used. As a particularly preferable reducing agent, JP-A-56-146133
Examples include reducing agents represented by the following general formula (1) described in No.

[Chemical formula] In the formula, R ¹ and R ² are hydrogen atoms, or carbon atoms having 1 to 30 carbon atoms (preferably 1 to 30), which may have a substituent.
-4) represents an alkyl group, and R ¹ and R ² may be ring-closed to form a heterocycle. R ³ , R ⁴ , R ⁵ and R ⁶ are hydrogen atoms, halogen atoms, hydroxy groups,
Represents an amino group, an alkoxy group, an acylamido group, a sulfonamide group, an alkylsulfonamide group, or an alkyl group having 1 to 30 carbon atoms (preferably 1 to 4) that may have a substituent, and R ³ and R ¹ And R ⁵ and R ² may each be ring-closed to form a heterocycle. M represents an alkali metal atom, an ammonium group, a nitrogen-containing organic base, or a compound containing a quaternary nitrogen atom. The nitrogen-containing organic base in the above general formula (1) is an organic compound containing a nitrogen atom that exhibits basicity capable of forming an inorganic salt and a salt, and particularly important organic bases include amine compounds. Examples of chain amine compounds include primary amines, secondary amines, and tertiary amines, and examples of cyclic amine compounds include pyridine, quinoline, and piperidine, which are well-known examples of typical heterocyclic organic bases. , imidazole and the like. In addition, hydroxylamine,
Compounds such as hydrazine and amidine are also useful as chain amines. In addition, as the salt of the nitrogen-containing organic base, inorganic acid salts of the organic base (eg, hydrochloride, sulfate, nitrate, etc.) as described above are preferably used. On the other hand, examples of the compound containing quaternary nitrogen in the above general formula include salts or hydroxide compounds of nitrogen compounds having a tetravalent covalent bond. Next, preferred specific examples of the reducing agent represented by the general formula (1) are shown below.

[ka]

[ka]

[ka]

[ka]

[ka]

[ka]

[ka]

[ka]

[ka]

[ka]

[ka]

[ka]

[ka]

[ka]

[ka]

[ka]

[ka]

[ka]

[ka]

[ka]

[ka]

[ka]

[ka]

[ka]

[ka]

[ka]

[ka]

[ka]

[ka]

[Chemical formula] The reducing agent represented by the above general formula (1) can be prepared by a known method such as Heuben-Beil, Methods der Organizien Chemie, Band XI/2.
(Houben-Weyl, Methoden der Organischen
Chemie, Band XI/2) pages 645-703. Furthermore, it is also possible to use two or more of the above-mentioned reducing agents at the same time, or to use a black and white developing agent described below in combination for the purpose of increasing developability. Moreover, the dye-donating substance used in the present invention is
-152440, 59-154445, etc., compounds that release dyes upon oxidation, compounds that lose their ability to release dyes when oxidized, compounds that release dyes when reduced, etc. (or In the case where only a silver image is simply obtained, a developing agent as described below can also be used. For example, phenols (e.g. p-phenylphenol, p-methoxyphenol, 2,6-di-tert-butyl-p-cresol, N-methyl-
p-aminophenol, etc.), sulfonamidophenols [e.g. 4-benzenesulfonamidophenol, 2-benzenesulfonamidophenol, 2,6-dichloro-4-benzenesulfonamidophenol, 2,6-dibromo-4-(p-aminophenol, etc.) −
toluenesulfonamide) phenol, etc.], or polyhydroxybenzenes (e.g. hydroquinone, tert-butylhydroquinone, 2,6-dimethylhydroquinone, chlorohydroquinone,
carboxyhydroquinone, catechol, 3-carboxycatechol, etc.), naphthols (e.g. α-naphthol, β-naphthol, 4-aminonaphthol, 4-methoxynaphthol, etc.), hydroxybinaphthyls and methylene bisnaphthols [e.g. 1,1′ -dihydroxy-2,2'-binaphthyl, 6,6'-dibromo-2,2'-dihydroxy-1,1'-binaphthyl, 6,6-dinitro-
2,2'-dihydroxy-1,1'-binaphthyl,
4,4'-dimethoxy-1,1'-dihydroxy-
2,2'-binaphthyl, bis(2-hydroxy-1
-naphthyl)methane, etc.], methylenebisphenols [e.g. 1,1-bis(2-hydroxy-
3,5-dimethylphenyl)-3,5,5-trimethylhexane, 1,1-bis(2-hydroxy-3-tert-butyl-5-methylphenyl)methane, 1,1-bis(2-hydroxy- 3,5-di-tert-butylphenyl)methane, 2,6-methylenebis(2-hydroxy-3-tert-butyl-
5-methylphenyl)-4-methylphenol,
α-phenyl-α,α-bis(2-hydroxy-
3-tert-butyl-5-methylphenyl)methane, 1,1-bis(2-hydroxy-3,5-dimethylphenyl)-2-methylpropane, 1,1,
5,5-tetrakis(2-hydroxy-3,5-
dimethylphenyl)-2,4-ethylpentane,
2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane, 2,2-bis(4-hydroxy-3-methyl-5-tert-butylphenyl)propane, 2,2-bis(4- Hydroxy-
3,5-di-tert-butylphenyl)propane, etc.], ascorbic acids, 3-pyrazolidones,
Mention may be made of pyrazolones, hydrazones and paraphenylenediamines. These developing agents mentioned above can also be used alone or in combination of two or more. The amount of the reducing agent used in the heat-developable photosensitive material of the present invention depends on the type of photosensitive silver halide, the type of organic acid silver salt, and the type of other additives used, but usually is in the range of 0.01 to 1500 mol, preferably 0.1 to 200 mol, per 1 mol of photosensitive silver halide. Examples of the binder used in the heat-developable photosensitive material of the present invention include synthetic or natural polymers such as polyvinyl butyral, polyvinyl acetate, ethyl cellulose, polymethyl methacrylate, cellulose acetate butyrate, polyvinyl alcohol, polyvinylpyrrolidone, gelatin, and phthalated gelatin. One or more molecular substances can be used in combination. In particular, it is preferable to use gelatin or a derivative thereof in combination with a hydrophilic polymer such as polyvinylpyrrolidone or polyvinyl alcohol, and more preferably the following binder described in JP-A-59-229556. This binder includes gelatin and vinylpyrrolidone polymer. The vinylpyrrolidone polymer may be polyvinylpyrrolidone, which is a homopolymer of vinylpyrrolidone, or one or two of other monomers copolymerizable with vinylpyrrolidone.
Copolymers with the above (including graft copolymers)
It may be. These polymers can be used regardless of their degree of polymerization. The polyvinylpyrrolidone may be a substituted polyvinylpyrrolidone, with preferred polyvinylpyrrolidone having a molecular weight of 1000
~400,000. Other monomers copolymerizable with vinylpyrrolidone include (meth)acrylic acid esters such as acrylic acid, methacrylic acid and alkyl esters thereof, vinyl alcohols, vinyl acetates, vinyl imidazoles, (meth)acrylamides, Examples include vinyl monomers such as vinyl carbinols and vinyl alkyl ethers, but at least
Preferably, 20% (weight %, the same applies hereinafter) is polyvinylpyrrolidone. Preferred examples of such copolymers have a molecular weight of 5,000 to 400,000. Gelatin may be treated with lime or acid, and may be ossein gelatin, pitgskin gelatin, hydrogelatin, or modified gelatin obtained by esterifying or phenylcarbamoylating these gelatins. In the above binder, gelatin preferably accounts for 10 to 90%, more preferably 20 to 60%, and vinylpyrrolidone accounts for 5 to 90%, more preferably 10 to 80% of the total binder amount. %. The binder may contain other polymeric substances, such as gelatin and a mixture of polyvinylpyrrolidone with a molecular weight of 1,000 to 400,000 and one or more other polymeric substances, gelatin and a polymer with a molecular weight of 5,000 to 400,000.
A mixture of the vinylpyrrolidone copolymer and one or more other polymeric substances is preferred. Other polymeric substances that can be used include polyvinyl alcohol, polyacrylamide, polymethacrylamide, polyvinyl butyral, polyethylene glycol, polyethylene glycol ester, or proteins such as cellulose derivatives, and polysaccharides such as starch and gum arabic. Examples include natural substances. These range from 0 to 85%, preferably from 0 to 85%.
It may contain 70%. Note that the vinyl pyrrolidone polymer may be a crosslinked polymer, but in this case, it is preferable to crosslink it after coating it on the support (including the case where the crosslinking reaction progresses by leaving it naturally). The amount of binder used is usually 0.05 g to 50 g per layer per m ² of support, preferably
It is 0.1g to 10g. Further, the binder is preferably used in an amount of 0.1 to 10 g, more preferably 0.25 to 4 g, per 1 g of the dye-providing substance. Examples of the support used in the heat-developable photosensitive material of the present invention include polyethylene film, cellulose acetate film, polyethylene terephthalate film, synthetic plastic film such as polyvinyl chloride, photographic base paper, printing paper, baryta paper, and resin coated paper. Examples include paper supports, and supports obtained by coating and curing an electron beam curable resin composition on these supports. In the heat-developable photosensitive material of the present invention, and when the photosensitive material is of a transfer type and uses an image-receiving member, at least one of the heat-developable photo-sensitive material and the image-receiving member includes:
It is preferable to add various heat solvents. The thermal solvent used in the present invention is a compound that promotes at least one of thermal development and thermal transfer. Regarding these compounds, for example, U.S. Patent No. 3,347,675, U.S. Pat.
Examples include polar organic compounds as described in Japanese Patent Application No. 59-47787, etc. Particularly useful in the present invention include, for example, urea derivatives (e.g.
dimethylurea, diethylurea, phenylurea, etc.), amide derivatives (e.g. acetamide,
benzamide, etc.), polyhydric alcohols (e.g.
1,5-pentanediol, 1,6-pentanediol, 1,2-cyclohexanediol, pentaerythritol, trimethylolethane, etc.),
Or polyethylene glycols can be mentioned. Among the above thermal solvents, water-insoluble solid thermal solvents described below are more preferably used. A water-insoluble solid thermal solvent is a compound that is solid at room temperature but becomes liquid at high temperatures (60°C or higher, preferably 100°C or higher, particularly preferably 130°C or higher and 250°C or lower), and is an inorganic/organic compound. The ratio of
3.0, preferably 0.7 to 2.5, particularly preferably 1.0 to
It is a compound in the range of 2.0, and the solubility in water at room temperature is less than 1. Specific examples of water-insoluble solid thermal solvents are shown below.
Not limited to these.

【table】

【table】

【table】

[Table] Many compounds used as water-insoluble solid heat solvents are commercially available, and can be easily synthesized by those skilled in the art. The method of adding the water-insoluble heat solvent is not particularly limited, but
There are methods such as adding by pulverizing and dispersing using a ball mill, sand mill, etc., adding by dissolving in a suitable solvent, and adding by dissolving in a high boiling point solvent and adding as an oil-in-water dispersion. It is preferable to pulverize and disperse the solid particles using a sand mill or the like and add them while maintaining the solid particle shape. Layers to which the water-insoluble solid thermal solvent is added include a photosensitive silver halide emulsion layer, an intermediate layer, a protective layer, an image-receiving layer of an image-receiving member, and the like, so that the respective effects can be obtained. The amount of water-insoluble heat solvent added is usually 10% to 500% by weight, preferably 50% to 50% by weight of the binder amount.
It is 300% by weight. In addition, even if the melting point of the water-insoluble solid thermal solvent of the present invention is higher than the heat development temperature, the melting point will be lowered by being added to the binder.
It can be effectively used as a thermal solvent. The photothermographic material of the present invention may contain various additives in addition to the above-mentioned components, if necessary. For example, melt formers such as acetamide and succinimide described in U.S. Patent No. 3,438,776, compounds such as polyalkylene glycols described in U.S. Pat. There are non-aqueous polar organic compounds having a melting point of 20°C or higher, such as lactones having -CO-, _-SO2- , and -SO- groups. Furthermore, benzophenone derivatives described in JP-A-49-115540, JP-A-53-24829, JP-A-53-
Phenol derivatives described in No. 60223, JP-A-Sho
Carboxylic acids described in No. 58-118640, JP-A-Sho
Examples include polyhydric alcohols described in No. 58-198038 and sulfamoylamide compounds described in JP-A No. 59-84236. Further, a color toning agent known in heat-developable photosensitive materials may be added as a development accelerator to the photothermographic material of the present invention. As a coloring agent,
For example, JP-A No. 46-4928, No. 46-6077, No. 49-
No. 5019, No. 49-5020, No. 49-91215, No. 49-
No. 107727, No. 50-2524, No. 50-67132, No. 50
−67641, No. 50-114217, No. 52-33722, No.
No. 52-99813, No. 53-1020, No. 53-55115, No. 53-55115, No.
No. 53-76020, No. 53-125014, No. 54-156523,
No. 54-156524, No. 54-156525, No. 54-156526
No. 55-4060, No. 55-4061, No. 55-32015
Publications such as No. 2140406 and West German Patent No. 2140406,
No. 2141063, No. 2220618, U.S. Patent No. 3847612,
No. 3782941, No. 4201582 and JP-A-57-
No. 207244, No. 57-207245, No. 58-189628, No. 58-189628, No.
Phthalazinone, phthalimide, pyrazolone, quinazolinone, N-hydroxynaphthalimide, benzoxazine, naphthoxazinedione, 2,3-dihydro-phthalazinedione, 2,
3-dihydro-1,3-oxazine-2,4-dione, oxypyridine, aminopyridine, hydroxyquinoline, aminoquinoline, isocarbostyryl, sulfonamide, 2H-1,3-benzothiazine-2,4-(3H) dione, benzotriazine, mercaptotriazole, dimercaptotetrazapentalene, aminomercaptotriazole, acylaminomercaptotriazole, phthalic acid, naphthalic acid, phthalamic acid, etc.
A mixture of one or more of these and an imidazole compound, a mixture of at least one acid or acid anhydride such as phthalic acid or naphthalic acid, or a phthalazine compound, furthermore, a mixture of phthalazine and maleic acid, itaconic acid, or quinoline. Examples include combinations of acids, gentisic acid, and the like. As an antifoggant, for example, US Pat.
Higher aliphatic compounds (e.g., behenic acid, stearic acid, etc.) described in No. 3645739, mercury salts described in Japanese Patent Publication No. 11113/1982, and N-halogen compounds described in Japanese Patent Publication No. 47419/1983 (e.g. N-halogenoacetamide, N-halogenosuccinimide, etc.), mercapto compound-releasing compounds described in U.S. Pat. sulfonic acids, etc.), carboxylic acid lithium salts (e.g. lithium laurate) described in No. 51-47419, oxidizing agents (e.g. perchlorates, inorganic peroxides, persulfates, etc.), sulfinic acids or thiosulfonic acids described in No. 53-19825, 2-thiouracils described in No. 51-3223, simple sulfur described in No. 51-26019, No. 51 -42529, 51-81124, same
Disulfide and polysulfide compounds described in No. 55-93149, rosins or diterpenes (e.g. abietic acid, pimaric acid, etc.) described in No. 51-57435, free carboxy groups or sulfonic acid groups described in No. 51-104338. 1,2,4-triazole or 5-triazole as described in JP-A-54-51821 and U.S. Pat. No. 4,137,079;
Mercapto-1',2,4-triazole, 55-
Thiosulfinate esters described in No. 140833,
1,2,3,4-thiatriazoles described in No. 55-142331, No. 59-46641, No. 59-57233,
Examples include dihalogen compounds or trihalogen compounds described in No. 59-57234, and thiol compounds described in No. 59-111636. In addition, as other anti-fogging agents,
Hydroquinone derivatives described in No. 56506 (e.g.
di-t-octylhydroquinone, dodecanylhydroquinone, etc.), hydroquinone derivatives and benzotriazole derivatives (e.g., 4-sulfobenzotriazole,
-carboxybenzotriazole, etc.) can be preferably used in combination. As a silver image stabilizer, U.S. Patent No. 3707377
5-methoxycarbonylthio-1-phenyltetrazole described in Belgian Patent No. 768071, JP-A No. 768071; Monohalo compounds (e.g., 2-bromo-2-tolylsulfonylacetamide, etc.) described in JP-A-50-119624, bromine compounds described in JP-A-50-120328 (e.g., 2-bromomethylsulfonylbenzothiazole, 2, 4-bis(tribromomethyl)-6-methyltriazine, etc.), and tribromoethanol described in JP-A-53-46020. Also, various monohalogenated organic antifoggants for silver halide emulsions described in JP-A-50-119624 can be used. Other image stabilizers include U.S. Pat.
No. 3220846, No. 4082555, No. 4088496, JP-A-Sho
50-22625, Research Disclosure (RD) No. 12021, RD No. 15168, RD No. 15567, RD No.
Compounds called activator precursors that release basic substances by heat, such as guanidinium, which releases a base by decarboxylation with heat, described in No. 15732, No. 15733, No. 15734, No. 15776, etc. Compounds such as trichloroacetate, aldnamide compounds such as galactonamide, amine imides, 2-carboxycarboxamide, etc.
In addition, sodium phosphate base generators described in JP-A-56-130745 and JP-A-56-132332, compounds that generate amines through intramolecular nucleophilic reactions described in British Patent No. 2079480, JP-A-56-130745 and JP-A-56-132332; Aldoxime carbamates described in No. 59-157637, No. 59-
Hydroxamic acid carbamates etc. described in No. 166943, No. 59-180537, No. 59-174830, No. 59-174830,
Examples include base releasing agents described in No. 59-195237 and the like. Furthermore, U.S. Patent No. 3301678, U.S. Patent No. 3506444, U.S. Patent No.
No. 3824103, No. 3844788, No. RD12035, No. 3824103, No. 3844788, No. RD12035, No.
Illithiuronium compounds, s-carbamoyl derivatives of mercapto-containing compounds, and nitrogen-containing heterocyclic compounds described in US Pat.
No. 4012260, No. 4060420, No. 4207392,
The activator stabilizer and activator stabilizer precursor described in RD15109 and RD17711, etc., are developed with a nitrogen-containing organic base such as the α-sulfonylacetic acid group of 2-aminothiazoline or trichloroacetate, and an acylhydrazine compound, respectively. It can be used for the purpose of promoting the image, or for the purpose of stabilizing the image. Also, for example, JP-A-56-130745, JP-A No. 59-
Development may be carried out in the presence of a small amount of water as described in No. 218443, or water may be supplied by spraying a small amount of water or applying a certain amount of water before heating.
As described in US Pat. No. 3,312,550 and the like, development may be performed using hot steam, hot air containing moisture, or the like.
In addition, compounds that release water into the heat-developable photosensitive material, such as compounds containing water of crystallization such as those described in Japanese Patent Publication No. 44-26582, such as sodium phosphate dodecahydrate, ammonium alum diquadrate, etc., may be added to the heat-developable photosensitive material. It may be included in the material. In addition, various additives such as antihalation dyes, optical brighteners, hardeners, antistatic agents, plasticizers, and spreading agents, coating aids, and the like may be used. In the heat-developable photosensitive material of the present invention, colloidal silica is added to at least one of the heat-developable photosensitive layer and the non-photosensitive layer (e.g., undercoat layer, intermediate layer, protective layer, etc.) for the purpose of improving film properties. Can be used. The colloidal silica used in the present invention is a colloidal solution of silicic anhydride with an average particle size of 3 to 120 mμ mainly using water as a dispersion medium, and the main components are:
It is SiO ₂ (silicon dioxide). Regarding colloidal silica, for example, JP-A-56-109336, JP-A No. 53-
It is described in No. 123916, No. 53-112732, No. 53-100226, etc. The amount of colloidal silica used is
The dry weight ratio to the binder of the layer to be mixed and coated is preferably in the range of 0.05 to 2.0. The heat-developable photosensitive material of the present invention contains an organic fluoro compound in at least one of the heat-developable photosensitive layer and the non-photosensitive layer (for example, an undercoat layer, an intermediate layer, a protective layer, etc.) for the purpose of improving film properties. can be used. Regarding the organic fluoro compounds used in the present invention, US Pat.
3754924, 3775126, 3850640, West German Patent Publication No. 1942665, 1961638, 2124262,
British Patent No. 1330356, Belgian Patent No. 742680, and Japanese Patent Application Laid-open Nos. 46-7781, 48-9715, and 49-
No. 46733, No. 49-133023, No. 50-99529, No. 50
−11322, No. 50-160034, No. 51-43131, No.
No. 51-129229, No. 51-106419, No. 53-84712,
No. 54-111330, No. 56-109336, No. 59-30536
No. 59-45441 and Special Publication No. 47-9303, same.
Examples include compounds described in No. 48-43130 and No. 59-5887, and these compounds can be preferably used. In the heat-developable photosensitive material of the present invention, an antistatic agent can be used in at least one of the heat-developable photosensitive layer and the non-photosensitive layer (eg, undercoat layer, intermediate layer, protective layer, etc.). Antistatic agents used in the present invention include British Patent No. 1466600, Research Disclosure No. 15840, British Patent No. 16258
No. 16630, U.S. Patent No. 2327828, U.S. Pat.
No. 2861056, No. 3206312, No. 3245833, No.
No. 3428451, No. 3775126, No. 3963498, No.
No. 4025342, No. 4025463, No. 4025691, No. 4025342, No. 4025463, No. 4025691, No.
Examples include compounds described in No. 4025704 and the like, and these can be preferably used. In the heat-developable photosensitive material of the present invention, an ultraviolet absorber can be used in at least one of the heat-developable photosensitive layer and the non-photosensitive layer (eg, undercoat layer, intermediate layer, protective layer, etc.). As the ultraviolet absorber used in the present invention, benzophenone compounds (for example, JP-A No. 46-2784,
U.S. Pat. Nos. 3,215,530 and 3,698,907), butadiene compounds (e.g., U.S. Pat.
4045229), 4-thiazolidone compounds (e.g., those described in U.S. Pat. No. 3,314,794 and U.S. Pat. No. 3,352,681), benzotriazole compounds substituted with aryl groups (e.g., Japanese Patent Publication No. 36-10466,
No. 41-1687, No. 42-26187, No. 44-29620,
48-41572, JP-A No. 54-95233, JP-A No. 57-
142975, U.S. Patent No. 3253921, U.S. Patent No. 3533794,
Same No. 3754919, No. 3794493, No. 4009038, Same No.
4220711, 4323633, Research Disclosure 22519), benzoxide compounds (e.g.
U.S. Pat. No. 3,700,455), cinnamate ester compounds (e.g., U.S. Pat. No. 3,705,805;
No. 3707375, as described in JP-A-52-49029)
can be mentioned. In addition, U.S. Patent No.
Those described in No. 3499762 and JP-A-54-48535 can also be used. Ultraviolet absorbing couplers (e.g., α-naphthol cyan dye-forming couplers) and ultraviolet absorbing polymers (e.g., JP-A-58-111942, JP-A No. 178-351, JP-A-181041, JP-A-59-59)
-19945, No. 23344, and those described in publications). In the heat-developable photosensitive material of the present invention, a hardening agent can be used in at least one of the heat-developable photosensitive layer and the non-photosensitive layer (eg, undercoat layer, intermediate layer, protective layer, etc.). Hardeners used in the present invention include aldehyde-based and aziridine-based hardeners (for example, PB Report
19921, U.S. Patent No. 2950197, U.S. Patent No. 2964404,
2983611, 3271175, Japanese Patent Publication No. 46-40898, and JP-A-50-91315), isoxazole type (for example, US Pat. No. 331609) ), epoxy systems (e.g. U.S. Patent No. 3047394, West German Patent No.
1085663, the specifications of British Patent No. 1033518, those described in Japanese Patent Publication No. 1983-35495), vinyl sulfones (for example, PB Report 19920, West German Patent No. 1100942, West German Patent No. 2337412, West German Patent No. 2545722, same
No. 2635518, No. 2742308, No. 2749260, British Patent No. 1251091, Patent Application No. 1974-54236, No. 48-
110996, U.S. Patent No. 3539644, and U.S. Patent No. 3490911), acryloyl type (e.g., those described in Japanese Patent Application No. 1983-27949 and U.S. Patent No. 3640720) , carbodiimide type (e.g., U.S. Pat. No. 2,938,892, U.S. Pat. No. 4,043,818,
4061499, those described in Japanese Patent Publication No. 46-38715, and Japanese Patent Application No. 15095/1983), triazine type (for example, West German Patent No. 2410973,
2553915, U.S. Patent No. 3325287, and JP-A-12722), other maleimide-based, acetylene-based, methanesulfonic acid ester-based, and N-methylol-based hardeners are used alone. Or they can be used in combination. As a useful combination technique, for example, West German Patent Nos. 2447587 and 2505746
No. 2514245, U.S. Patent No. 4047957, U.S. Pat.
Specifications of No. 3832181 and No. 3840370, Japanese Unexamined Patent Application Publication No. 1973-
Examples include combinations described in Japanese Patent Publications No. 43319, No. 50-63062, No. 52-127329, and Japanese Patent Publication No. 32364-1983. In the heat-developable photosensitive material of the present invention, a polymer hardener can be used in at least one of the heat-developable photosensitive layer and the non-photosensitive layer (for example, undercoat layer, intermediate layer, protective layer, etc.). . Examples of the polymeric hardening agent used in the present invention include polymers having aldehyde groups (e.g., acrolein copolymers) described in US Pat. No. 3,396,029, US Pat. No. 3,362,827, and Research Disclosure No. 17333. (1978), etc., polymers having dichlorotriazine groups, U.S. Patent No.
Polymers having epoxy groups as described in No. 3623878,
Research Disclosure No. 16725 (1978),
U.S. Patent No. 4161407, Japanese Patent Application Publication No. 54-65033, No. 56
Examples include a polymer having an active vinyl group or a group that can be a precursor thereof, as described in Japanese Patent Application Laid-open No. 142524, and a polymer having an active ester group, as described in JP-A-56-66841. In the heat-developable photosensitive material of the present invention, a polymer is added to at least one of the heat-developable photosensitive layer and the non-photosensitive layer (for example, an undercoat layer, an intermediate layer, a protective layer, etc.) for the purpose of improving the physical properties of the film. Latex can be used. Preferred specific examples of the polymer latex used in the present invention include polymethyl acrylate, polyethyl acrylate, poly-n-butyl acrylate, a copolymer of ethyl acrylate and acrylic acid, a copolymer of vinylidene chloride and butyl acrylate, and a copolymer of butyl acrylate and acrylic acid. copolymers of vinyl acetate and butyl acrylate, copolymers of vinyl acetate and ethyl acrylate, copolymers of ethyl acrylate and 2-acrylamide, and the like. The preferred average particle size of the polymer latex is
It is 0.02 μm to 0.2 μm. The amount of polymer latex used is preferably 0.03 to 0.5 in dry weight ratio to the binder of the layer to which it is added. In the heat-developable photosensitive material of the present invention, various materials may be added to at least one of the heat-developable photosensitive layer and the non-photosensitive layer (for example, an undercoat layer, an intermediate layer, a protective layer, etc.) for the purpose of improving coating properties. surfactants can be used. The surfactant used in the present invention may be any of anionic, cationic, amphoteric and nonionic surfactants. Examples of anionic surfactants include alkyl carboxylates, alkyl sulfonates, alkylbenzenesulfonates, alkylnaphthalenesulfonates, alkyl sulfates, alkyl phosphates, N-acyl-N- Carboxy groups, sulfo groups, phospho groups, sulfate ester groups, phosphate ester groups, etc. such as alkyl taurines, sulfosuccinates, sulfoalkyl polyoxyethylene alkyl phenyl ethers, polyoxyethylene alkyl phosphates, etc. Those containing an acidic group are preferred. Examples of cationic surfactants include alkylamine salts, aliphatic or aromatic quaternary ammonium salts, heterocyclic quaternary ammonium salts such as pyridinium and imidazolium, and aliphatic or heterocyclic phosphonium or sulfonium salts. etc. are preferred. Examples of amphoteric surfactants include amino acids,
Aminoalkyl sulfonic acids, aminoalkyl sulfates or phosphoric esters, alkyl betaines,
Amine oxides and the like are preferred. Examples of nonionic surfactants include saponin (steroid type), alkylene oxide derivatives (such as polyethylene glycol, polyethylene glycol/polypropylene glycol condensates, polyethylene glycol alkyl ethers or polyethylene glycol alkylaryl ethers, polyethylene glycol esters, polyethylene glycol sorbitan esters, polyalkylene glycol alkylamines or amides, polyethylene oxide adducts of silicones), glycidol derivatives (e.g. alkenylsuccinic acid polyglycerides, alkylphenol polyglycerides), fatty acid esters of polyhydric alcohols, alkyl sugars Esters and the like are preferred. The heat-developable photosensitive material of the present invention includes, for the purpose of improving developability, improving image dye transferability, improving optical properties, etc.
Non-photosensitive silver halide grains can be contained in at least one of the heat-developable photosensitive layer and the non-photosensitive layer (eg, undercoat layer, intermediate layer, protective layer, etc.). The non-photosensitive silver halide grains used in the present invention may have any silver halide composition such as silver chloride, silver bromide, silver iodide, silver iodobromide, silver chlorobromide, silver chloroiodobromide, etc. Can be used. The preferred particle size of the non-photosensitive silver halide grains is about 0.3 μm or less. In addition, the amount added is calculated in terms of silver amount for the layer to be added.
A range of 0.02 to 3 g/m ² is preferred. In the heat-developable photosensitive material of the present invention, for the purpose of improving film properties, at least one of the heat-developable photosensitive layer and the non-photosensitive layer (e.g., undercoat layer, intermediate layer, protective layer, etc.) may contain, for example, a special layer. A vinyl polymer having a carboxyl group or a sulfo group as described in Japanese Patent Publication No. 104338/1986 can be included. The amount of the vinyl polymer used is preferably in the range of 0.05 to 2.0 in terms of dry weight ratio to the binder of the layer to which it is added. The heat-developable photosensitive material of the present invention basically includes (1) photosensitive silver halide, (2) in one heat-developable photosensitive layer.
It is preferable to contain a reducing agent, (3) a dye-providing substance, (4) a binder, and further contain (5) an organic silver salt if necessary. However, these do not necessarily need to be contained in a single photographic constituent layer; for example,
The heat-developable photosensitive layer is divided into two layers, and the above (1), (2), (4),
The component (5) is contained in the heat-developable photosensitive layer on one side,
The dye-providing substance (3) may be contained in two or more constituent layers as long as they can react with each other, such as by containing the dye-providing substance (3) in the layer on the other side adjacent to this photosensitive layer. In addition, the heat-developable photosensitive layer is divided into a high-sensitivity layer and a low-sensitivity layer.
It may be divided into two or more layers such as a high concentration layer and a low concentration layer. The heat-developable photosensitive material of the present invention has one or more heat-developable photosensitive layers on a support. In the case of color, it generally has three heat-developable photosensitive layers with different color sensitivities, and each photosensitive layer forms or releases dyes with different hues upon heat development.
Typically, a yellow dye is used in the blue-sensitive layer, a magenta dye is used in the green-sensitive layer, and a cyan dye is used in the red-sensitive layer, but the invention is not limited to this. It is also possible to combine a near-infrared sensitive layer. The structure of each layer can be arbitrarily selected depending on the purpose. For example, a structure in which a red-sensitive layer, a green-sensitive layer, and a red-sensitive layer are sequentially formed on the support, or a structure in which a blue-sensitive layer is sequentially formed on the support. There are configurations such as a structure in which a green-sensitive layer, a red-sensitive layer is formed, or a structure in which a green-sensitive layer, a red-sensitive layer, and a blue-sensitive layer are sequentially formed on a support. In addition to the heat-developable photosensitive layer, the heat-developable photosensitive material of the present invention can be provided with non-photosensitive layers such as an undercoat layer, an intermediate layer, a protective layer, a filter layer, a backing layer, and a release layer. To coat the heat-developable photosensitive layer and these non-photosensitive layers on the support, a method similar to that used for coating and preparing general silver halide photosensitive materials can be applied. That is, there are methods and apparatuses for the dip method, roller method, reverse roll method, air knife method, doctor blade method, spray method, bead method, extrusion method, stretch flow method, curtain method, and the like. The heat-developable photosensitive material of the present invention is preferably provided with a protective layer. Hereinafter, this will be referred to as the protective layer of the present invention. Various additives used in the photographic field can be used in the protective layer of the present invention. The additives include various matting agents, colloidal silica, slipping agents, organic fluoro compounds (especially fluorosurfactants), antistatic agents, ultraviolet absorbers, high-boiling organic solvents, antioxidants, hydroquinone derivatives, Examples include polymer latexes, surfactants (including polymeric surfactants), hardeners (including polymeric hardeners), organic silver salt particles, and non-photosensitive silver halide particles. The matting agent used in the protective layer of the present invention is fine particles of inorganic or organic substances that are incorporated into a heat-developable photosensitive material to increase the roughness of the surface of the photosensitive material and make it matte. be. A method of using a matting agent to prevent adhesion that occurs during the production, storage, and use of photosensitive materials, and to prevent charging that occurs due to contact, friction, and peeling between materials of the same or different types is as follows: Well known in the industry. As a specific example of a matte agent, JP-A-Sho
Silicon dioxide described in No. 50-46316, JP-A-53-
Alkali-soluble matting agents such as alkyl methacrylate/methacrylic acid copolymers described in No. 7231, No. 58-66937, and No. 60-8894; alkalis having anionic groups described in JP-A-58-166341; Soluble polymer, combination of two or more types of fine particle powders with different Mohs hardnesses, described in JP-A-58-145935, JP-A-58-145935
Combination of oil droplets and fine particle powder described in No. 147734, JP-A-Sho
59-149356, a combination of two or more spherical matting agents with different average particle diameters, a combination of a fluorinated surfactant and a matting agent described in JP-A-56-44411, and British Patent No. 1055713, U.S. Patent No. 1939213, same
No. 2221873, No. 2268662, No. 2322037, No. 2221873, No. 2268662, No. 2322037, No.
No. 2376005, No. 2391181, No. 2701245, No. 2376005, No. 2391181, No. 2701245, No.
No. 2992101, No. 3079257, No. 3262782, No.
No. 3443946, No. 3516832, No. 3539344, No.
No. 3591379, No. 3754924, No. 3767448, JP-A-Sho
Organic matting agents described in No. 49-106821, No. 57-14835, etc., West German Patent No. 2529321, British Patent No. 760775, No. 1260772, U.S. Patent No. 1201905
No. 2192241, No. 3053662, No. 3062649,
3257206, 3322555, 3353958, 3353958, 3322555, 3353958,
No. 3370951, No. 3411907, No. 3437484, No.
No. 3523022, No. 3615554, No. 3635714, No.
Inorganic matting agents described in No. 3769020, No. 4021245, No. 4029504, etc., or JP-A-46-
No. 7781, No. 49-106821, No. 51-6017, No. 53-
No. 116143, No. 53-100226, No. 57-14835, No.
No. 57-82832, No. 53-70426, No. 59-149357,
Matting agents having physical properties as described in Japanese Patent Publication No. 57-9053 and EP-107378 are preferably used. In the protective layer of the present invention, the amount of the matting agent added is preferably 10 mg/2.0 g per m ² , more preferably 20 mg to 1.0 g. The particle size of the matte agent is 0.5~
The thickness is preferably 10 μm, more preferably 1.0 to 6 μm. The matting agent may be used in combination of two or more types. Examples of the slipping agent used in the protective layer of the present invention include solid paraffin, oils and fats, surfactants, natural waxes, synthetic waxes, etc. Specifically, examples include French Patent No. 2180465 and British Patent No.
No.955061, No.1143118, No.1270578, No.955061, No.1143118, No.1270578, No.
No. 1320564, No. 1320757, JP-A-49-5017, No.
No. 51-141623, No. 54-159221, No. 56-81841,
Research Disclosure
Disclosure) No. 13969, U.S. Patent No. 1263722,
No. 2588765, No. 2739891, No. 3018178, No. 2588765, No. 2739891, No. 3018178, No.
No. 3042522, No. 3080317, No. 3082087, No.
No. 3121060, No. 3222178, No. 3295979, No. 3295979, No.
No. 3489567, No. 3516832, No. 3658573, No.
Those described in No. 3679411, No. 3870521, etc. can be preferably used. The protective layer of the present invention contains a high boiling point organic solvent (for example, US Pat.
No. 2322027, No. 2533514, No. 2882157, Tokko Akira
46-23233, British Patent No. 958441, British Patent No. 1222753
No. 2,353,262, U.S. Pat. No. 3,676,142, U.S. Pat.
No. 3700454, Japanese Patent Publication No. 50-82078, No. 51-27921,
51-141623 etc., esters (e.g. phthalate esters, phosphate esters, fatty acid esters, etc.), amides (e.g. fatty acid amides,
(sulfonic acid amide, etc.), ethers, alcohols, paraffins, etc. ) may contain oil droplets in which a water-insoluble oil compound is emulsified and dispersed. Furthermore, these oil droplets may contain photographic additives for various purposes. Binders used in the protective layer of the present invention include polyvinyl butyral, polyvinyl acetate, ethyl cellulose, polymethyl methacrylate,
One or a combination of two or more synthetic or natural polymeric substances such as cellulose acetate butyrate, polyvinyl alcohol, polyvinylpyrrolidone, polyethyloxazoline, polyacrylamide, gelatin, and phthalated gelatin can be used. In particular, gelatin (including gelatin derivatives), polyvinylpyrrolidone (preferably molecular weight 1000-400000), polyvinyl alcohol (molecular weight 1000-400000),
100,000) and polyoxazoline (molecular weight is preferably 1,000 to 800,000) alone or in combination of two or more of these binders are preferred, and gelatin alone or gelatin is compatible with gelatin such as polyvinylpyrrolidone, polyvinyl alcohol, and polyoxazoline. Particularly preferred is a binder in which a hydrophilic polymer with good properties is used. Gelatin may be treated with lime, acid, or ion exchange, and may be ossein gelatin, pitguskin gelatin, hydrogelatin, or modified gelatin obtained by esterifying or phenylcarbamoylating these gelatins. good. The thickness of the protective layer of the present invention is preferably 0.05 to 5 μm, more preferably 0.1 to 1.0 μm. The protective layer may be a single layer or may be composed of two or more layers. Further, in order to increase film strength and prevent film destruction, it is also preferable that the hardness of the protective layer is greater than that of the photosensitive layer. One way to make the hardness of the protective layer higher than that of the photosensitive layer, that is, to control the hardness of each layer, is to use a diffusion-resistant hardener. By using it in the protective layer, only the degree of hardness of the protective layer can be made greater than that of the photosensitive layer. Polymer hardeners are known as diffusion-resistant hardeners, such as those disclosed in US Pat. Nos. 3057723 and 3396029.
Hardeners described in JP-A No. 4161407, JP-A No. 58-50528, etc. can be used. Another way to control the degree of hardening for each layer is to include a diffusible hardener (for example, a vinyl sulfone hardener) only in the protective layer, or to make the content of the protective layer higher than that of the photosensitive layer. The hardness of the protective layer can be made higher than that of the photosensitive layer by quickly drying the protective layer after simultaneous multi-layer coating. The heat-developable photosensitive material of the present invention usually has a temperature of 80°C after imagewise exposure.
In the temperature range ~200℃, preferably 100℃~170℃,
Developing is accomplished by simply heating for 1 second to 180°C, preferably 1.5 seconds to 120 seconds. Transfer of the diffusible dye to the image-receiving layer may be carried out simultaneously with heat development by bringing the image-receiving member into close contact with the photosensitive surface of the photosensitive material and the image-receiving layer during heat development, or by bringing the image-receiving member into close contact with the image-receiving member after heat development and heating. Alternatively, the transfer may be performed by supplying water and then applying heat if necessary. Further, preheating may be performed in a temperature range of 70° C. to 180° C. before exposure. Also, JP-A-60-143338
As described in Japanese Patent Application No. 60-3644, the photosensitive material and the image-receiving member may be preheated at a temperature of 80°C to 250°C immediately before thermal development transfer in order to improve their mutual adhesion. . Various exposure means can be used for the photothermographic material according to the present invention. The latent image is obtained by imagewise exposure to radiation, including visible light. Light sources commonly used for regular color printing, such as tungsten lamps, mercury lamps, xenon lamps,
Laser beams, CRT beams, etc. can be used as light sources. As the heating means, all methods applicable to ordinary photothermographic materials can be used, such as contacting with a heated block or plate, contacting with a heated roller or drum, passing through a high-temperature atmosphere, etc. Alternatively, high-frequency heating may be used, or furthermore, a conductive layer containing a conductive substance such as carbon black may be provided on the back surface of the photosensitive material of the present invention or on the back surface of the image receiving member for thermal transfer to remove the Joule heat generated by energization. You can also use it. There are no particular restrictions on the heating pattern, including preheating and then reheating, heating at a high temperature for a short time, or at a low temperature for a long time.
Although it is possible to continuously raise, lower, repeat, or even heat discontinuously, a simple pattern is preferable. Alternatively, a method in which exposure and heating proceed simultaneously may be used. The image-receiving layer of the image-receiving member effectively used in the present invention may have the function of receiving the dye in the heat-developable photosensitive layer released or formed by heat development, such as a tertiary amine or quaternary ammonium salt. Among the polymers described in US Pat. No. 3,709,690 are preferably used. For example, as a polymer containing an ammonium salt, polystyrene-co-N,N,N-tri-n-hexyl-N-
The vinyl-benzylammonium chloride ratio is from 1:4 to 4:1, preferably 1:1. Examples of polymers containing tertiary amines include polyvinylpyridine. A typical image-receiving layer for diffusion transfer is obtained by mixing a polymer containing ammonium salt, tertiary amine, etc. with gelatin, polyvinyl alcohol, etc., and coating the mixture on a support. Another useful dye-receiving material is JP-A-57
-The glass transition temperature described in No. 207250, etc. is 40℃
The above examples include those formed of heat-resistant organic polymeric substances of 250°C or less. These polymers may be supported on a support as an image-receiving layer, or may themselves be used as a support. Examples of the heat-resistant organic polymer substances include polystyrene, polystyrene derivatives having a substituent having 4 or less carbon atoms, polyvinylcyclohexane, polydivinylbenzene, polyvinylpyrrolidone, polyvinylcarbazole, polyallylbenzene, polyvinyl alcohol, polyvinyl formal, and Polyacetals such as polyvinyl butyral, polyvinyl chloride, chlorinated polyethylene, polytrichloride fluoroethylene, polyacrylonitrile,
Poly-N,N-dimethylallylamide, polyacrylate with p-cyanophenyl group, pentachlorophenyl group and 2,4-dichlorophenyl group, polyacrylchloroacrylate, polymethyl methacrylate, polyethyl methacrylate, polypropyl methacrylate, Polyisopropyl methacrylate, polyisobutyl methacrylate, poly-tert-butyl methacrylate, polycyclohexyl methacrylate, polyethylene glycol dimethacrylate, poly-2-cyano-
Examples include polyesters such as ethyl methacrylate and polyethylene terephthalate, polycarbonates such as polysulfone and bisphenol A polycarbonate, polyanhydrides, polyamides, and cellulose acetates. Also,
Polymer Handbook 2nd ed.
Synthetic polymers with a glass transition temperature of 40°C or lower, described in EHImmergut (ed.) John Wiley & Sons, are also useful. Generally, it is useful for the molecular weight of the polymer substance to be 2,000 to 200,000. These polymeric substances may be used alone or in a blend of two or more types, or may be used in combination of two or more types as a copolymer. Useful polymers include cellulose acetates such as triacetate and diacetate; polyamides made from combinations such as heptamethylene diamine and terephthalic acid; fluorene dipropylamine and adipic acid; hexamethylene diamine and diphenic acid; hexamethylene diamine and isophthalic acid;
diethylene glycol and diphenylcarboxylic acid,
Examples include polyester, polyethylene terephthalate, and polycarbonate made of a combination of bis-p-carboxyphenoxybutane and ethylene glycol. These polymers may be modified. For example, polyethylene terephthalate using cyclohexanedimethanol, isophthalic acid, methoxypolyethylene glycol, 1,2-dicarbomethoxy-4-benzenesulfonic acid, etc. as a modifier is also effective. A particularly preferred image-receiving layer is JP-A-59-
Examples include a layer made of polyvinyl chloride described in No. 223425 and a layer made of polycarbonate and a plasticizer described in JP-A-60-19138. These polymers can also be used as a support and an image-receiving layer (image-receiving member), in which case the support may be formed from a single layer or from multiple layers. good. As the support for the image-receiving member, any material such as a transparent support or an opaque support may be used. Titanium oxide, barium sulfate, calcium carbonate,
Supports containing pigments such as talc, baryta paper, RC paper laminated with thermoplastic resin containing pigments on paper, cloth, glass, metals such as aluminum, etc., and on these supports Examples include a support coated with an electron beam curable resin composition containing a pigment and cured, and a support coated with a coating layer containing a pigment on these supports. In particular, a support that is coated with an electron beam curable resin composition containing a pigment on paper and cured, or a support that has a pigment coating layer directly on the paper or an electron beam curable resin composition on the pigment coating layer. The support coated with the composition and cured can be used as an image-receiving member as it is because the resin layer itself can be used as an image-receiving layer. When the present invention is applied to a heat-developable color light-sensitive material, the various polymers mentioned above can be used as a mordant for a dye image and as an image-receiving layer. It may be an image-receiving element or the image-receiving layer may be a single layer that is part of a heat-developable color photographic material. If necessary, an opacifying layer (reflection layer) is provided in the photosensitive material.
can also be included, and such layers are used to reflect the desired amount of radiation, such as visible light, that can be used to view the dye image in the image-receiving layer. The opacifying layer (reflective layer) can contain various reagents that provide the necessary reflection, such as titanium dioxide. The image-receiving layer of the image-receiving member can also be formed into a type that can be peeled off from the heat-developable photosensitive layer. For example, after imagewise exposure of a heat-developable color photosensitive material, an image-receiving layer can be superimposed on the heat-developable photosensitive layer and uniformly heat-developed. Further, after imagewise exposure and uniform heat development of the heat-developable color light-sensitive material, an image-receiving layer may be superimposed and heated at a temperature lower than the development temperature to transfer the dye image released or formed from the dye-providing substance. The present invention is characterized in that the acid or acid precursor is contained in the core material of the microcapsule.
If it is less than % by weight, it may be added and used in combination without being included in the microcapsules. Further, in order to control thermal development, a base or a base precursor may be used in combination without being included in the microcapsules. [Effects of the Invention] A heat-developable photosensitive material with high image contrast was obtained by incorporating an acid or an acid precursor into the core material of microcapsules. Further, even if the heat-developable photosensitive material of the present invention is stored unused for a long period of time, the contrast of the image obtained therefrom does not deteriorate, that is, it can be obtained with excellent shelf life. [Examples] Specific examples of the present invention will be described in detail below, but the aspects of the present invention are not limited thereto. Example 1 <Preparation of Microcapsule 1> 12.0 g of sulfosuccinic acid bis-2-ethylhexyl ester sodium salt and 6.0 g of polyoxyethylene-4-lauryl ether were mixed into 80 ml of n-
Dissolve in hexane. Then, slowly add a solution of 5 g of boric acid dissolved in 80 ml of distilled water and stir thoroughly. The mixed solution is transferred to a cylindrical double-walled reaction vessel. Then, with thorough stirring, 0.05 g of ethylene glycol dimethacrylate and 5 g of methyl methacrylate were added, followed by 1 mg of sodium riboflavin-5'-phosphate and potassium persulfate, and dissolved. Thereafter, the mixture is irradiated with light under a nitrogen atmosphere at a temperature of 35±5° C. for 7 to 10 hours while stirring gently until the monomer disappears. N-hexane was distilled off from the resulting microcapsule suspension under reduced pressure.
Next, water is added, the surfactant is removed by ultrafiltration, and the microcapsules are isolated by centrifugation. The size of the obtained microcapsule particles is
It was 100 to 300 nm. This microcapsule will be referred to as microcapsule 1. <Preparation of Microcapsule 2> Microcapsules were obtained in the same manner as in the preparation of Microcapsule 1 except that citric acid was used instead of boric acid. This will be referred to as microcapsule 2. <Preparation of microcapsule 3> 5 g of exemplified compound AP-2 to 80 ml of distilled water
In addition, after adding 80g of glass beads, they were dispersed with a sand grinder at 200 rpm for about 4 hours.
The resulting dispersion was then dispersed using ultrasonic waves for about 10 minutes. Microcapsules were obtained in the same manner as in the preparation of Microcapsule 1, except that this dispersion was used instead of the aqueous solution of boric acid. The particle size of the obtained microcapsules was 300 to 600 nm. This will be referred to as microcapsule 3. <Preparation of Microcapsules 4> Microcapsules were obtained in the same manner as in the preparation of Microcapsules 3 except that AP-51 was used instead of the exemplary compound AP-2. This will be referred to as microcapsule 4. <Preparation of Microcapsules 5> Microcapsules were obtained in the same manner as in the preparation of Microcapsules 3 except that AP-6 was used instead of the exemplary compound AP-2. This will be referred to as microcapsule 5. Example 2 [Preparation of organic silver salt dispersion] 5 obtained by reacting 5-methylbenzotriazole and silver nitrate in a water-alcohol mixed solvent
-Methylbenzotriazole silver 144g, 5-
0.4 g of methylbenzotriazole, 200 ml of a 20 wt% aqueous solution of polyvinylpyrrolidone (K-30), and 540 ml of water were dispersed in an alumina ball mill, and 200 ml of the above aqueous polyvinylpyrrolidone solution was added to make 1000 ml. [Preparation of photosensitive silver halide emulsion] Preparation of silver iodobromide emulsion At 50°C, JP-A No. 57-92523, No. 57-
Using the mixing and stirring method described in Specification No. 92524, 500 ml of an aqueous solution B containing 11.6 g of potassium iodide and 130 g of potassium bromide was prepared in A solution prepared by dissolving 20 g of ossein gelatin, 1000 ml of distilled water, and ammonia. and 500 ml of an aqueous solution C containing 1 mol of silver nitrate and ammonia were simultaneously added while keeping the pAg and PH constant. Furthermore, by controlling the addition speed of liquid B and liquid C, the silver iodide content was 7 mol%, positive 6
A core emulsion with a face shape and an average grain size of 0.25 μm was prepared.
Next, by coating a silver halide shell with a silver iodide content of 1 mol % in the same manner as above,
Regular hexahedron, average grain size 0.3μm (shell thickness 0.05μm)
A core/shell type silver halide emulsion was prepared.
(The monodispersity was 8%.) Each of the above emulsions was washed with water and desalted to obtain a yield of 700 ml. Furthermore, a photosensitive silver halide emulsion was prepared using the silver halide prepared above in the following manner. Preparation of red-sensitive silver iodobromide emulsion Said silver iodobromide emulsion 700ml 4-hydroxy-6-methyl-1,3,3a-7
Tetrazaindene 0.4g Gelatin 32g Sodium thiosulfate 10mg 1% methanol solution of the following sensitizing dye 80ml Distilled water 1200ml

[Chemical] [Preparation of reducing agent solution] 93.2 g of reducing agent R-11, 207 ml of a 20 wt% aqueous solution of polyvinylpyrrolidone (K-30), 40 ml of a 5 wt% aqueous solution of the following surfactant, water, and a citric acid aqueous solution to pH 7. .0, 600ml. (surfactant)

[Preparation of hot solvent dispersion] 430 g of p-toluamide and 1410 ml of a 1.0 wt% aqueous solution of polyvinylpyrrolidone (K-90) were dispersed in a ball mill to obtain a hot solvent dispersion. [Preparation of dye-donor polymer dispersion] 105 g of dye-donor polymer PM-5, 4.0 g of the following hydroquinone compound, and 300 ml of ethyl acetate were mixed and dissolved by heating, and 248 ml of Alkanol XC (manufactured by DuPont) 5 wt% aqueous solution was prepared. , 26.4g of photographic gelatin,
Phenylcarbamoylated gelatin (type
The mixture was mixed with 1440 ml of an aqueous gelatin solution containing 34.6 g of 17819PC (manufactured by Rousslow) and dispersed using an ultrasonic homogenizer. After distilling off the ethyl acetate, water was added to make a total volume of 1590 ml to obtain a dispersion.

[Formula] [Preparation of microcapsule dispersion] Prepared in Example 1 (microcapsules 1 to 1)
5) 15g each in 200ml of 3.9wt% gelatin aqueous solution
A microcapsule dispersion was prepared by adding it to the solution and dispersing it with an ultrasonic homogenizer. [Preparation of heat-developable photosensitive material] The following coating solution was applied to a wet film thickness of 114.3 μm on a 180 μm thick photographic transparent polyethylene terephthalate film having a subbing layer, dried, and the photosensitive material (sample No. 1) was prepared. Created. (Coating liquid composition) Organic silver salt dispersion 80.0ml Red-sensitive silver halide emulsion 38.4ml Reducing agent solution 48.0ml Heat solvent dispersion 94.8g Dye-donor polymer dispersion 127ml Microcapsule 1 dispersion 45ml Photographic gelatin 10wt% Aqueous solution 30.9ml Phenylcarbamoylated gelatin 10wt% aqueous solution
27.7ml Correction water 22.0ml Hardener solution (2.5wt% aqueous solution of sodium 2,4-dichloro-6-hydroxy-S-triazine)
13.3ml Total 512ml (However, the pH of the coating solution was 6.3.) Also, microcapsule 1 was mixed with microcapsule 2.
Sample No. 1 was prepared in the same manner as Sample No. 1 except that ~5 was changed.
2 to 5 were created. Comparative samples were prepared that did not contain a microcapsule dispersion (Sample No. 7) and in which the same amount of acid precursor was added as a methanol solution instead of the microcapsule dispersion (Sample No. 6). However, the amount of gelatin applied per unit area of samples 6 and 7 was made to be the same as that of sample No. 1. [Preparation of image-receiving member] On the other hand, an ethylene chloride solution of polycarbonate (average molecular weight 25,000, L-1250, Teijin Kasei) was coated on photographic baryta paper and dried so that the polycarbonate amount was 15.0 g/m ² to receive an image. I made the parts. [Evaluation of photographic properties] The photothermographic material was exposed to light through a step wedge, and the photothermographic material was exposed to light through a step wedge.
Heat development was performed at 150° C. for 90 seconds, and the film was immediately peeled off to obtain a cyan-colored transferred image on the image-receiving member. In order to evaluate raw storage stability, the same heat-developable photosensitive material as described above was stored at 50°C in an atmosphere of 80% relative humidity for 48 hours.
After being left for a certain period of time, exposure and heat development were carried out in the same manner. (Forced Deterioration Test) The maximum density and minimum density of the obtained transferred image and the minimum density of the forced deterioration test sample were measured as reflection densities using a Sakura densitometer (PDA-65, manufactured by Roku Konishi). The results are shown in Table-1.

[Table] As is clear from Table 1, sample No. 7 to which no acid or acid precursor was added could not obtain a sufficient maximum concentration. Sample No. 6, in which the acid precursor was added without being contained in the microcapsules, was able to obtain a sufficient maximum concentration, but the acid precursor gradually decomposed during raw storage, so the concentration increased to the minimum concentration. On the other hand, samples Nos. 1 to 5 of the present invention, in which acids or acid precursors were added in microcapsules, had high stability during raw storage, and the acids or acid precursors were effectively and quickly released during thermal development. released and can only increase the maximum concentration. Example 3 The dye-donating substance PM-5 in Example-2 was
The same operation as in Example 2 was performed except that the sample No. 1 was changed to PM-4 and the microcapsules and acid precursors in Sample No. 1 were changed as shown in Table 2. The results obtained are shown in Table-2.

[Table] As is clear from Table 2, similar to Example 2, only the sample of the present invention has excellent characteristics such as a sufficiently high maximum density and low fog even after raw storage. Example 4 [Preparation of dye-donating substance dispersion] 14 g of a dye-donating substance, 22 g of tricresyl phosphate, and 0.6 g of sodium 2-ethylhexyl succinate sulfonate were added to ethyl acetate.
Dissolve in 40ml and mix with 7.5wt% gelatin aqueous solution,
Ultra-high speed homogenizer (Biotron, BT-
10S) for 15 minutes at 15,000 R.PM, ethyl acetate was distilled off and 240ml of the dye-providing compound dispersion was obtained.
I got it. [Preparation of thermal solvent dispersion] A thermal solvent dispersion was prepared in the same manner as in Example-2 except that p-toluamide in Example-2 was changed to α-toluenesulfonamide. [Preparation of green-sensitive silver iodobromide emulsion] Silver iodobromide emulsion used in Example-2 700ml 4-hydroxy-6-methyl-1,3,3a-7
Tetrazaindene 0.4g Gelatin 32g Sodium thiosulfate 10mg 1% methanol solution of the following sensitizing dye 80ml Distilled water 1200ml

[Creation of heat-developable photosensitive material] (Coating solution composition) Green-sensitive silver halide emulsion 120ml Heat solvent dispersion 36g Dye-providing substance dispersion 115ml Microcapsule 5 dispersion prepared in Example-2
32ml Photographic gelatin 10wt% aqueous solution 40ml Guanidine trichloroacetic acid 10wt% ethanol solution
65ml Decaglyceryl monolaurate 5wt% aqueous solution 20ml 4,4-dimethyl-1-p-tolyl-3-pyrazolidinone 1wt% methanol solution 18ml Correction water 23ml Hardener solution (tetravinylsulfonylmethylmethane
2 wt% methanol solution) 17 ml, total 480 ml (however, the pH of the coating solution was 6.5) The above coating solution composition was coated on the same support as in Example-2 to a wet film thickness of 45.7 μm, dried, and heat developed. Created photosensitive materials. (Sample No. 12) Comparative samples include one that does not contain a microcapsule dispersion (sample No. 13), and one that contains the same amount of acid precursor as a methanol solution instead of the microcapsule dispersion (sample No. 14). I made it. However, the amount of gelatin applied per unit area of Samples 13 and 14 was made to be the same. [Preparation of Image Receiving Member] The following layers were sequentially coated on a 100 μm thick transparent polyethylene terephthalate film. (1) A layer made of polyacrylic acid. (7.00g/m ² ) (2) A layer made of cellulose acetate. (4.00 g/m ² ) (3) A layer consisting of a 1:1 copolymer of styrene and N-benzyl-N,N-dimethyl-N-(3-maleimidopropyl)ammonium chloride and gelatin. (Copolymer 3.00g/m ² ) (Gelatin 3.00g/m ² ) (4) Urea and polyvinyl alcohol (saponification degree
98%). Urea 4.0 g/m ² Polyvinyl alcohol 3.0 g/m ² [Evaluation of photographic properties] The heat-developable photosensitive material was exposed to light through a step wedge, and combined with the image receiving member.
While performing thermal development at 150° C. for 1 minute, the film was immediately peeled off to obtain a magenta transferred image on the image receiving member. In addition, a forced deterioration test was conducted in the same manner as in Example-2. Note that the maximum density and minimum density were measured as permeation density. The results obtained are shown in Table 3.

[Table] As is clear from Table 3, sample No. 13 to which no acid precursor was added had a large amount of fogging.
In the case of reducing dye-donor substances, acid has the effect of inhibiting development, so in sample No. 14, in which acid precursor was added without being contained in the microcapsules, acid was released in the latter half of development; However, during raw storage, acid is gradually released, which inhibits development and reduces the maximum density. Sample No. 12 of the present invention, in which the acid precursor was contained in microcapsules and was added, was excellent in that a high maximum concentration could be obtained even after long-term storage, and fogging could be prevented. Example 5 The following layers were coated in sequence on a 100 μm thick transparent polyethylene terephthalate film support. (1) A layer consisting of a 1:1 copolymer of styrene and N-benzyl-N,N-dimethyl-N-(3-maleimidopropyl)ammonium chloride, gelatin, and an acid precursor. (Image receiving layer) Copolymer 3.00g/m ² Gelatin 3.00g/m ² Acid precursor (AP-6) 0.3g/m ² (Added as methanol solution) (2) Layer consisting of titanium oxide and gelatin. Titanium oxide 13.0g/m ² Gelatin 3.0g/m ² (3) Urea and polyvinyl alcohol (saponification degree
98%). Urea: 4.0 g/m ² Polyvinyl alcohol: 3.0 g/m ² (4) The same heat-developable photosensitive layer as Sample No. 13 of Example-4 The above-mentioned heat-developable photo-sensitive material is designated as Sample No. 15, and the sample No.
Except that the microcapsule dispersion of Example-4 was added instead of the acid precursor in layer (1) of No. 15 so that the acid precursor was 0.3 g/m ² and the gelatin was 3.0 g/m ² . , Sample No. 15
I made No.16. Samples Nos. 15 and 16 were exposed to light from the heat-developable photosensitive layer side, the same film as the support was superimposed on the surface of the heat-developable photosensitive layer, and heat development was performed at 150° C. for 1 minute. In addition, a forced deterioration test was conducted in the same manner as in Example 2, and the obtained results are shown in Table 4.

[Table] As is clear from Table 4, in sample No. 15 in which the acid precursor was added to the image-receiving layer without being contained in the microcapsules, the maximum concentration decreased. On the other hand, sample No. 16, in which the acid precursor was contained in microcapsules and added to the image-receiving layer, had the same effect as Example 4 in that it prevented the maximum concentration from decreasing and further prevented the maximum concentration from decreasing during raw storage. be.

Claims (1)

[Claims] 1 At least photosensitive silver halide on the support,
1. A photothermographic material comprising a dye-providing substance, a reducing agent, a binder, and microcapsules, wherein the core material of the microcapsules contains at least one of an acid and an acid precursor.