JP2005195859A - Silver salt photothermographic dry imaging material, and image recording method and image forming method using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a silver salt photothermographic dry imaging material, having low fog, high sensitivity, high density, superior image preservability, improved soil resistance to a thermal developing drum and improved resistance to odor, and to provide an image recording method and an image forming method which uses the same. <P>SOLUTION: The silver salt photothermographic dry imaging material comprises particles of a light-insensitive silver salt of an aliphatic carboxylic acid, light-sensitive silver halide grains; a reducing agent for silver ions; a binder and a dye microcapsule dispersion, wherein the light-sensitive silver halide grains are those which are converted from a surface latent image type to an internal latent image type in a thermal developing process, whereby the surface sensitivity is lowered from that prior to the thermal developing process; and the dye microcapsule dispersion is dye-containing microcapsules whose wall membranes are formed, by dissolving a dye and a binder in a volatile organic solvent, dispersing the resulting solution in a water-soluble resin solution and making the volatile organic solvent evaporated. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a silver salt photothermographic dry imaging material having low fog, high sensitivity, high maximum density, excellent image storability after heat development processing, and improved stain resistance and odor resistance to an imager thermal development drum. The present invention relates to an image recording method and an image forming method using the same.

  In recent years, in the fields of medical treatment and printing plate making, waste liquid resulting from wet processing of image forming materials has become a problem in terms of workability, and reduction of processing waste liquid is strongly desired from the viewpoint of environmental conservation and space saving. Yes. Therefore, there is a need for technology related to photothermographic materials for photographic technology that enables efficient exposure, such as laser imagers and laser imagesetters, and that can form clear black images with high resolution. It is coming. As a technique related to the photothermographic material, for example, a silver salt photothermographic dry imaging material containing an organic silver salt, a photosensitive silver halide and a reducing agent on a support (for example, Patent Documents 1 and 2 and Non-Patent Document 1). See.) Is known. Since this silver salt photothermographic dry imaging material does not use any solution processing chemicals, it has an advantage that it can provide a user with a simpler system that does not impair the environment.

  However, in the silver salt photothermographic dry imaging material, after exposure, usually only by heat development at 80 to 250 ° C., and fixing is not performed. Therefore, after heat development, all of silver halide, organic silver salt, reducing agent, etc. Alternatively, since a part of the metal remains, metal silver is generated by heat or light during a long-term storage process, and there is a problem that the image quality such as the color tone of the silver image is easily changed. Conventionally, as a technique for preventing the fluctuation and deterioration of the silver image due to the influence of the light, a halogen compound that oxidizes silver by light induction has been used, and examples of the halogen compound have been disclosed (for example, (See Patent Documents 3 to 5.) However, these disclosed compounds generally have a tendency to develop an oxidative function even by thermal decomposition, and thus have the effect of preventing fog formation and growth, but they inhibit silver image formation and are sensitive. It has become clear that there are problems that cause adverse effects such as reducing the maximum density and silver coverage (covering power). As one method for solving this problem, a method using a dye that absorbs irradiation light, a so-called antihalation dye, is known. This antihalation dye is most effective when incorporated between the photosensitive layer and the support. However, since it has interlayer diffusibility, it is difficult to immobilize it in a desired layer. When the photosensitive layer is applied simultaneously or successively, the light diffuses into the photosensitive layer, and the light coming into contact with the silver halide is produced, resulting in a decrease in sensitivity. As another method, in a method in which a layer having a pigment that absorbs irradiation light is provided between the photosensitive layer and the support, residual color after heat development becomes a problem. In view of such circumstances, in particular, when applying a coating solution containing an organic solvent, it is desired to develop a technique for stably fixing a dye between a desired layer, particularly a photosensitive layer and a support. It was.

  In order to solve the above problem, a technique intended to prevent halation by laser light using a dye having solubility in an organic solvent has been disclosed (for example, see Patent Documents 6 and 7). It is hard to say that it is.

In order to achieve this immobilization, various methods of microencapsulating dyes have been studied by those skilled in the art, but microcapsules having a particle size that can be stably added and applied to the desired layer to be added are synthesized. However, it is impossible to keep the dye contained in the core stably in the organic solvent in the particle size.
US Pat. No. 3,152,904 (Claims) US Pat. No. 3,487,075 (Claims) JP-A-7-2781 (Claims) JP-A-6-208193 (Claims) JP-A-50-120328 (Claims) JP-A-8-201959 (Claims) JP 2001-83655 A (Claims) D. H. Klosterber; “Dry Silver Photographic Materials” (Handbook of Imaging Materials, Mar. Dekker, Inc.) (p. 48, 1991)

  The present invention has been made in view of the above problems, and its object is to achieve low fogging, high sensitivity, high maximum density, excellent image preservation after heat treatment, and contamination of the heat developing drum of a heat developing machine imager. A silver salt photothermographic dry imaging material having improved resistance and odor resistance, and an image recording method and an image forming method using the same.

  The above object of the present invention is achieved by the following configurations.

(Claim 1)
A silver salt photothermographic dry imaging material comprising a non-photosensitive aliphatic carboxylic acid silver salt particle, a photosensitive silver halide particle, a silver ion reducing agent, a binder and a dye microcapsule dispersion, wherein the photosensitive silver halide The silver halide grains in which the grains are converted from the surface latent image type to the internal latent image type in the thermal development process and the surface sensitivity is lower than before the thermal development process, and the dye microcapsule dispersion is in accordance with the following method A silver salt photothermographic dry imaging material, which is a prepared dye microcapsule dispersion A.

<Dye microcapsule dispersion A>
After a composition in which a dye and a binder are dissolved in a volatile organic solvent capable of dissolving the dye and the binder is dispersed in an aqueous solution of a water-soluble resin, the volatile organic solvent is evaporated to form a wall film (shell). After forming a microcapsule containing a dye, water is evaporated and dried, and then the microcapsule dispersion in which the microcapsule is dispersed in an organic solvent (Claim 2)
A silver salt photothermographic dry imaging material comprising a non-photosensitive aliphatic carboxylic acid silver salt particle, a photosensitive silver halide particle, a silver ion reducing agent, a binder and a dye microcapsule dispersion, wherein the photosensitive silver halide The silver halide grains in which the grains are converted from the surface latent image type to the internal latent image type in the thermal development process and the surface sensitivity is lower than before the thermal development process, and the dye microcapsule dispersion is in accordance with the following method A silver salt photothermographic dry imaging material, which is a prepared dye microcapsule dispersion B.

<Dye microcapsule dispersion B>
After a composition in which a dye and a binder are dissolved in a volatile organic solvent capable of dissolving the dye and the binder is dispersed in an aqueous solution of a water-soluble resin, the volatile organic solvent is evaporated to form a wall film (shell). After forming a microcapsule containing a dye, a colloidal silica is added, water is evaporated and dried, and then the microcapsule is dispersed in an organic solvent (Claim 3)
A silver salt photothermographic dry imaging material comprising a non-photosensitive aliphatic carboxylic acid silver salt particle, a photosensitive silver halide particle, a silver ion reducing agent, a binder and a dye microcapsule dispersion, wherein the photosensitive silver halide The silver halide grains in which the grains are converted from the surface latent image type to the internal latent image type in the thermal development process and the surface sensitivity is lower than before the thermal development process, and the dye microcapsule dispersion is in accordance with the following method A silver salt photothermographic dry imaging material, wherein the dye microcapsule dispersion C is prepared.

<Dye microcapsule dispersion C>
After a composition in which a dye and a binder are dissolved in a volatile organic solvent capable of dissolving the dye and the binder is dispersed in an aqueous solution of a water-soluble resin, the volatile organic solvent is evaporated to form a wall film (shell). Disperse dye microcapsules by forming a microcapsule containing a dye, adding a compound that reacts with the hydrophilic group of the water-soluble resin, evaporating and drying water, and then dispersing the microcapsule in an organic solvent Item (Claim 4)
The silver salt photothermographic dry imaging material according to any one of claims 1 to 3, wherein the water-soluble resin used for the preparation of the dye microcapsule dispersion is gelatin or gum arabic.

(Claim 5)
Expose white light or light in a specific spectral sensitization region through an optical wedge for a fixed exposure time, and heat develop under normal practical heat development conditions, then set the sensitivity obtained based on the characteristic curve to S ₁ Heat treatment is performed under the same conditions as the practical heat development conditions before, and then white light or light in a specific spectral sensitization region is exposed through an optical wedge for a fixed exposure time, and further heat development is performed under the practical heat development conditions. after, when the sensitivity obtained on the basis of the characteristic curve was S _2, silver salt photothermal according to any one of claims 1 to 4, S ₂ / S ₁ is equal to or more than 0.1 Photo dry imaging material.

(Claim 6)
The silver salt photothermographic image according to any one of claims 1 to 5, wherein the photosensitive silver halide grains contain a dopant that functions as an electron trap at least after thermal development in the grains. Dry imaging material.

(Claim 7)
The surface of the photosensitive silver halide grain is spectrally sensitized by adsorbing a spectral sensitizing dye, and the effect of the spectral sensitization substantially disappears after the thermal development process. The silver salt photothermographic dry imaging material according to any one of claims 1 to 6.

(Claim 8)
The surface of the photosensitive silver halide grain is chemically sensitized, and the effect of the chemical sensitization substantially disappears after the thermal development process. 2. A silver salt photothermographic dry imaging material according to item 1.

(Claim 9)
The surface of the photosensitive silver halide grains is subjected to spectral sensitization by adsorbing chemical sensitization and spectral sensitizing dyes, and the effects of the chemical sensitization and spectral sensitization after the thermal development process are substantially realized. The silver salt photothermographic dry imaging material according to any one of claims 1 to 6, wherein the material disappears automatically.

(Claim 10)
A method for recording an image by exposing the silver salt photothermographic dry imaging material according to any one of claims 1 to 9, wherein the exposure is a laser beam scanning exposure apparatus in which the scanning laser beam is a vertical multi-beam. An image recording method comprising:

(Claim 11)
A method for forming an image by subjecting the silver salt photothermographic dry imaging material according to any one of claims 1 to 9 to heat development, wherein the heat development is performed using the silver salt photothermographic dry imaging material. Is carried out in a state containing 40 to 4500 ppm of an organic solvent.

  According to the present invention, a silver salt photothermographic photograph having low fog, high sensitivity, high maximum density, excellent image storage stability after heat treatment, and improved stain resistance and odor resistance to a heat developing drum of a heat developing machine imager. A dry imaging material and an image recording method and an image forming method using the same can be provided.

  Hereinafter, the best mode for carrying out the present invention will be described in detail.

  In the silver salt photothermographic dry imaging material (hereinafter also referred to as imaging material or photosensitive material) of the present invention, non-photosensitive aliphatic carboxylic acid silver salt particles, photosensitive silver halide particles, silver ion reducing agent, binder and dye A silver salt photothermographic dry imaging material containing a microcapsule dispersion, wherein the photosensitive silver halide grains are converted from a surface latent image type to an internal latent image type in a thermal development process, and the surface sensitivity is a thermal development process. Silver halide grains lower than before, and the dye microcapsule dispersion is the dye microcapsule dispersion A, the dye microcapsule dispersion B, or the dye microcapsule dispersion C, By adopting a configuration, low fog, high sensitivity, high maximum density, excellent image storability after heat treatment, and heat developing machine It found that scum resistance and odor resistance can be realized a silver salt photothermographic dry imaging material which has been improved for the thermal development drum imager, a completed the invention.

  Details of the present invention will be described below.

  First, each component of the silver salt photothermographic dry imaging material of the present invention will be described.

[Microcapsules of the present invention]
The microcapsule as used in the present invention means a “micro container”, and is a general term for those having a particle diameter in the nanometer region to the millimeter region (not necessarily referring to the micrometer region container as the word source). . The microcapsule is composed of a core (core) and a wall film (shell) of the container. In addition, both mononuclear and binuclear cores are referred to as microcapsules in the present invention. The core portion of the dye microcapsule contains a dye and a binder. At this time, the ratio of the dye and the binder may be arbitrary, but is 0.1 / 99.9 to 99/1.

  In JP-A-2001-83655, a filter layer is formed on the same side as or opposite to the photosensitive layer in order to control the amount of light transmitted through the photosensitive layer or the wavelength distribution, or a dye is formed on the photosensitive layer. In the present invention, such a dye is added after being microencapsulated in a form that does not dissolve in the coating solvent, but a known dye is used. be able to. That is, known dye compounds that absorb light in various wavelength regions can be used depending on the color sensitivity of the photosensitive material.

  Examples of the dye that can be used in the present invention include dyes represented by the following general formula (I).

In the above general formula (I), Z ¹ and Z ² each represents a nonmetallic atom group necessary for forming a 5- or 6-membered nitrogen-containing heterocyclic ring which may be condensed, and R ¹ and R ² are each Represents an alkyl group, an alkenyl group or an aralkyl group, R ³ and R ⁵ each represent a hydrogen atom or a group of non-metallic atoms necessary to form a 5- or 6-membered ring connected to each other, and R ⁴ represents a hydrogen atom, an alkyl group Group, a halogen atom, an aryl group, —N (R ⁶ ) R ⁷ , —SR ⁸ or —OR ⁹ , R ⁶ represents a hydrogen atom, an alkyl group or an aryl group, R ⁷ represents an alkyl group, an aryl group, A sulfonyl group or an acyl group is represented, R ⁸ and R ⁹ each represents an alkyl group or an aryl group, and R ⁶ and R ⁷ may be linked to each other to form a 5- or 6-membered ring. a and b each represents 0 or 1, and X ⁻ represents an anion.

In the general formula (I), the 5- or 6-membered nitrogen-containing heterocyclic ring represented by Z ¹ or Z ² may be an oxazole ring, an isoxazole ring, a benzoxazole ring, a naphthoxazole ring or a thiazole ring. Benzothiazole ring, naphthothiazole ring, indolenine ring, benzoindolenine ring, imidazole ring, benzimidazole ring, naphthimidazole ring, quinoline ring, pyridine ring, pyrrolopyridine ring, fluropyrrole ring and the like. A 5-membered nitrogen-containing heterocyclic ring condensed with a benzene ring or a naphthalene ring is preferred, and an indolenine ring is most preferred. These rings may be substituted. As a substituent, a lower alkyl group (for example, methyl group, ethyl group), an alkoxy group (for example, methoxy group, ethoxy group), a phenoxy group (for example, unsubstituted phenoxy group, p-chlorophenoxy group), a carboxy group , Halogen atoms (Cl, Br, F), alkoxycarbonyl groups (for example, ethoxycarbonyl group), cyano groups, nitro groups, hydroxyl groups, and the like.

The alkyl group represented by R ¹ , R ² , R ⁴ , R ⁸ and R ⁹ is an alkyl group having 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms (for example, methyl group, ethyl group, propyl group, butyl group). Group, isobutyl group, pentyl group, hexyl group). Further, it may be substituted with a hydroxyl group, a carboxy group, a halogen atom (Cl, Br) or the like. The alkyl group represented by R ⁶ and R ⁷ is an alkyl group or alkoxycarbonylalkyl group represented by R ¹ , R ² , R ⁴ , R ⁸ and R ⁹ (for example, methoxycarbonylmethyl group, ethoxycarbonylmethyl group). Ethoxycarbonylethyl group). Examples of the 5- or 6-membered ring formed by connecting R ³ and R ⁵ to each other include cyclopentene and cyclohexene, and these rings have substituents (for example, a methyl group, a t-butyl group, and a phenyl group). You may have.

Examples of the halogen atom represented by R ⁴ include F, Cl, and Br. The aryl group represented by R ⁴ , R ⁶ , R ⁷ , R ⁸ and R ⁹ preferably has 6 to 12 carbon atoms, and examples thereof include a phenyl group and naphthyl. The aryl group may be substituted with the substituent described in the substituent that the ring of Z ¹ may have. The aralkyl group represented by R ¹ and R ² is preferably an aralkyl group having 7 to 12 carbon atoms (eg, benzyl group, phenylethyl group), and a substituent (eg, methyl group, alkoxy group, chloro atom). You may have. The alkenyl group represented by R ¹ and R ² is preferably an alkenyl group having 2 to 6 carbon atoms, for example, 2-pentenyl group, vinyl group, allyl group, 2-butenyl group, 1-propenyl. The group can be mentioned. The sulfonyl group represented by R ⁷ is preferably a sulfonyl group having 1 to 10 carbon atoms, and examples thereof include a mesyl group, a tosyl group, a benzenesulfonyl group, and an ethanesulfonyl group. The acyl group represented by R ⁷ is preferably an acyl group having 2 to 10 carbon atoms, and examples thereof include an acetyl group, a propionyl group, and a benzoyl group. R ⁶ and R ⁷ may be connected to each other to form a heterocycle. Examples of the heterocycle include piperidine, morpholine, piperazine and the like, and these rings may have a substituent (for example, methyl group, phenyl group, ethoxycarbonyl group). More preferably, R ¹ and R ² are alkyl groups, R ³ and R ⁴ are linked to form a 5- or 6-membered ring, and R ⁴ is —N (R ⁶ ) R ⁷ . More preferably, at least one of R ⁶ or R ⁷ is a phenyl group.

Examples of the anion represented by X ⁻ include halogen ions (Cl ⁻ , Br ⁻ , I ⁻ ), p-toluenesulfonic acid ions, ethyl sulfate ions, PF ₆ ⁻ , BF ₄ ⁻ , ClO ₄ ^{− and the} like.

  In the present invention, the dye represented by the following general formula (II) is more preferable.

In the general formula (II), Z ³ and Z ⁴ each represent a nonmetallic atom group necessary for forming a benzo- or naphtho-fused ring, R ¹⁰ and R ¹¹ each represent an alkyl group, an aralkyl group or an alkenyl group, R ¹² and R ¹⁴ each represent a hydrogen atom or a group of non-metallic atoms necessary to form a 5- or 6-membered ring by bonding to each other, and R ¹³ represents a hydrogen atom, an alkyl group, a halogen atom, an aryl group, —N ( R ¹⁹ ) represents R ²⁰ , —SR ²¹ or —OR ²² , R ¹⁹ , R ²⁰ , R ²¹ and R ²² each represent an alkyl group or an aryl group, and R ¹⁹ and R ²⁰ are linked to each other to form a ring. May be. R ¹⁵ , R ¹⁶ , R ¹⁷ and R ¹⁸ each represent an alkyl group, and R ¹⁵ and R ¹⁶ or R ¹⁷ and R ¹⁸ may be linked to form a ring. X ⁻ represents an anion.

Further, the general formula (II) will be described in detail. The benzo or naphth fused ring formed by Z ³ and Z ⁴ may be substituted with the substituent described for Z ¹ . The alkyl groups represented by R ¹⁰ , R ¹¹ , R ¹³ , R ¹⁵ , R ¹⁶ , R ¹⁷ , R ¹⁸ , R ²¹ and R ²² are the same as R ¹ , R ² , R described in the general formula (I). ^4, the same meaning as the alkyl group for R ⁸ and R ^9. R ¹⁵ and R ¹⁶ , R ¹⁷ and R ¹⁸ may be connected to each other to form a ring (eg, a cyclohexane ring). The alkyl group represented by R ¹⁹ and R ²⁰ has the same meaning as the alkyl group in R ⁶ and R ⁷ described in the general formula (I). The alkenyl group and aralkyl group represented by R ¹⁰ and R ¹¹ are synonymous with the alkenyl group and aralkyl group of R ¹ and R ² . The aryl group represented by R ¹³ , R ¹⁹ , R ²⁰ , R ²¹ and R ²² is synonymous with the aryl group of R ⁴ , R ⁶ , R ⁷ , R ⁸ and R ^{9 in} the general formula (I). . The halogen atom of R ^{13 has} the same meaning as the halogen atom of R ⁴ . The ring formation by R ¹⁹ and R ²⁰ is synonymous with the ring formation of R ⁶ and R ⁷ . X ^- is X in the general Formulas (I) ^- is synonymous. Preferably, R ¹⁰ and R ¹¹ are each an alkyl group, R ¹² and R ¹⁴ are linked to form a 5- or 6-membered ring, and R ¹³ is a compound represented by —N (R ¹⁹ ) R ^20. is there. Particularly preferred is a compound having a phenyl group in at least one of R ^{19 and} R ²⁰ .

  In the present invention, the dye represented by the general formula (III) is particularly preferable.

In the above general formula (III), Z ³ and Z ⁴ each represents a nonmetallic atom necessary for forming a benzo or naphtho fused ring, and R ¹⁰ and R ¹¹ each represents an alkyl group, an aralkyl group or an alkenyl group. , R ²³ and R ²⁴ each represents an alkyl group or an aryl group, R ¹⁵ , R ¹⁶ , R ¹⁷ and R ¹⁸ each represent an alkyl group, and R ¹⁵ and R ¹⁶ or R ¹⁷ and R ¹⁸ are linked to form a ring. May be formed. X ⁻ represents an anion.

Further, the general formula (III) will be described in detail. The benzo or naphth fused ring formed by Z ³ and Z ⁴ may be substituted with the substituent described for Z ¹ . The alkyl groups represented by R ¹⁰ , R ¹¹ , R ¹⁵ , R ¹⁶ , R ¹⁷ and R ¹⁸ are the alkyl groups in R ¹ , R, R ⁴ , R ⁸ and R ⁹ described in the general formula (I). It is synonymous with. R ¹⁵ and R ¹⁶ , R ¹⁷ and R ¹⁸ may be connected to each other to form a ring (eg, a cyclohexane ring). The alkyl group represented by R ²³ and R ²⁴ has the same meaning as the alkyl group in R ⁶ and R ⁷ described in the general formula (I). The alkenyl group and aralkyl group represented by R ¹⁰ and R ¹¹ are synonymous with the alkenyl group and aralkyl group of R ¹ and R ² . The aryl group represented by R ²³ and R ²⁴ has the same meaning as the aryl group of R ⁶ and R ^{7 in} the general formula (I). Ring formation by R ²³ and R ²⁴ is synonymous with the ring formation of R ⁶ and R ⁷ . X ^- is X in the general Formulas (I) ^- is synonymous. More preferably, R ¹⁰ and R ¹¹ are each an alkyl group, and R ²³ and R ²⁴ are each a phenyl group.

  Specific examples of the dye that can be used in the present invention are shown below, but the scope of the present invention is not limited thereto.

  The above dyes can be synthesized with reference to, for example, US Pat. No. 3,671,648 and the following synthesis examples.

<Synthesis Example 1: Synthesis of Exemplified Compound 2>
11.4 g of 1,2,3,3-tetramethyl-5-chloroindolenium-p-toluenesulfonate, 7 of N- (2,5-dianilinomethylenecyclopentylidene) -diphenylaluminum perchlorate 0.2 g, 100 ml of ethyl alcohol, 6 ml of acetic anhydride and 12 ml of triethylamine were stirred at an external temperature of 100 ° C. for 1 hour, and the precipitated crystals were separated by filtration. Subsequently, recrystallization was performed with 100 ml of methyl alcohol to obtain 7.3 g of Compound 2. The melting point measured according to a known measurement method was 270 ° C. or higher, λmax was 800.8 nm, and ε (molar extinction coefficient) was 2.14 × 10 ⁵ (chloroform).

  The other exemplified dyes can also be synthesized according to the same method as described above.

  Examples of the dye used in the present invention include a squarylium dye having a thiopyrylium nucleus, a squarylium dye having a pyrylium nucleus, a thiopyrylium croconium dye similar to a squarylium dye, or a pyrylium croconium dye.

  The compound having a squarylium nucleus is a compound having 1-cyclobuten-2-hydroxy-4-one in the molecular structure, and the compound having a croconium nucleus is 1-cyclopentene-2-hydroxy- in the molecular structure. It is a compound having 4,5-dione. Here, the hydroxyl group may be dissociated. Hereinafter, in the present specification, these pigments are collectively referred to as squarylium dyes for convenience.

  Hereinafter, the squarylium dye represented by the following general formula (1) used in the present invention will be described.

In the general formula (1), R ₁ and R ₂ each represent a monovalent substituent. The monovalent substituent is not particularly limited, but may be an alkyl group (for example, methyl group, ethyl group, isopropyl group, t-butyl group, methoxyethyl group, methoxyethoxyethyl group, 2-ethylhexyl group, 2-hexyldecyl). Group, benzyl group, etc.) and aryl groups (for example, phenyl group, 4-chlorophenyl group, 2,6-dimethylphenyl group, etc.), alkyl groups are more preferred, and t-butyl groups are preferred. It is particularly preferred. R ₁ and R ₂ may form a ring together. m and n each represents an integer of 0 to 4, preferably 2 or less.

  Hereinafter, the squarylium dye used in the present invention is exemplified.

  About these squarylium dyes, it is compoundable by the method described in Unexamined-Japanese-Patent No. 2000-160042.

  The core-forming binder that can be used in the present invention is a colorless and transparent or translucent natural polymer synthetic resin, polymer and copolymer, and other film-forming media such as cellulose acetate, cellulose acetate butyrate, poly (vinyl chloride) , Copoly (styrene-acrylonitrile), copoly (styrene-butadiene), poly (vinyl acetal) s (eg, poly (vinyl formal) and poly (vinyl butyral)), poly (esters), poly (urethanes), phenoxy There are resins, poly (vinylidene chloride), poly (epoxides), poly (carbonates), poly (vinyl acetate), cellulose esters, and poly (amides), and it is preferable to use a hydrophobic transparent binder. Preferable binders include polyvinyl butyral, cellulose acetate, cellulose acetate butyrate, polyester, polycarbonate, polyacrylic acid, polyurethane and the like. Among these, polyvinyl butyral, cellulose acetate, cellulose acetate butyrate, and polyester are particularly preferably used.

  Then, the component which comprises the wall film (shell) part of the microcapsule based on this invention is demonstrated.

  In the dye microcapsule according to the present invention, a water-soluble resin is used as a binder for the shell portion. The water-soluble resin functions as a protective colloid when the core component is dispersed in water and as a barrier so that the core portion does not dissolve in the organic solvent when dispersed in the organic solvent. Therefore, from this point of view, among the water-soluble resins, it is preferable to use polyvinyl alcohol or a derivative thereof, gelatin, or gelatin and / or gum arabic, and albumin, and further use gelatin and / or gum arabic. Is preferred.

  The most preferred water-soluble resin of the present invention includes gelatin and gum arabic, and examples of gelatin include lime-processed gelatin, acid-processed gelatin and Bull Society Science Photography Japan (Bull. Soc. Sci. Phot.Japan), No. 16, 30 (1966), an oxygen-treated gelatin may be used, and a hydrolyzate or oxygen-decomposed product of gelatin can also be used. Furthermore, gelatin derivatives and graft polymers of gelatin and other polymers can also be used. A commercially available gum arabic can be used as it is. Further, when gum arabic and gelatin are used in combination, the gelatin is preferably alkali-treated gelatin.

  Such a water-soluble resin has a hydrophilic group in the molecule, and when dispersed in an organic solvent, the dispersion is hindered by water carried by the hydrophilic group, or when the coating is dried. There is a concern that the film may be brushed. In order to solve the above problems, the dye microcapsule according to the present invention is characterized in that a compound capable of reacting with the hydrophilic group of the water-soluble resin is added after the wall film (shell part) is formed. It is one of.

  Examples of the compound that reacts with the hydrophilic group of the water-soluble resin include chromium salts, aldehydes (formaldehyde, glutaraldehyde, etc.), N-methylol compounds (dimethylol urea, etc.), active vinyl compounds (1, 3). , 5-triacryloyl-hexahydro-s-triazine, bis (vinylsulfonyl) methyl ether, N, N′-methylenebis- [β- (vinylsulfonyl) propionamide], etc.), active halogen compounds (2,4-dichloro- 6-hydroxy-s-triazine, etc.), mucohalogen acids (such as mucochloric acid), N-carbamoylpyridinium salts (such as (1-morpholinocarbonyl-3-pyridinio) methanesulfonate), haloamidinium salts (1- (1-chloro) -1-pyridinomethylene) pyrrolidiniu In particular, the active vinyl compounds described in JP-B-53-41220, JP-A-53-57257, JP-A-59-162546, JP-A-60-80846, and US Pat. No. 3,325. , 287 can be used alone or in combination. In addition, since the pore diameter of the shell can be reduced by this reaction, it is effective for controlling the release of the dye in the core in the organic solvent.

  In microcapsules having a particle size on the order of submicron, a water-soluble resin is used at a concentration (solid content) of 5 to 20% of the microcapsule aqueous dispersion to prevent diffusion of the dye in the core in the organic solvent. It is preferable to add an inorganic or organic compound capable of reacting with. If this concentration is higher than 20%, the compound itself reacting with the water-soluble resin may cause aggregation, or may react and aggregate between microcapsule particles. Conversely, if the concentration is lower than 5%, the barrier property against the solvent may be increased. Deteriorates and affects the dispersion state.

  The dye microcapsule according to the present invention is characterized by having colloidal silica on the surface of the shell, and further preferably has colloidal silica having a salt concentration of 1 ppm or less. Of course, the salt concentration may be zero.

  Colloidal silica usually has an average primary particle size as a stabilizer, which contains inorganic alkali components such as sodium hydroxide, potassium hydroxide, lithium hydroxide and ammonia, and organic alkali components such as tetramethylammonium ions. Refers to an aqueous dispersion of silicon dioxide fine particles of 5 nm to several tens of nm. In the present invention, colloidal silica having an alkali component content of 1 ppm or less is preferable from the viewpoint of effects. Since such colloidal silica is not dispersed by an ionic compound, it can be dispersed in either an aqueous solvent or an organic solvent, so that core-shell particles prepared in an aqueous solvent are redispersed in an organic solvent. Plays an important role. Such colloidal silica is commercially available from Fuso Chemical Industry Co., Ltd. under trade names such as PL-1, PL-2, and PL-3, and is easily available.

  The ratio of the core and shell of the dye microcapsule according to the present invention is preferably 1/99 to 99/1.

  Actually, whether or not the finished dye microcapsule particles have a core-shell structure can be evaluated as follows.

  First, the obtained microcapsule particles are dispersed in an organic solvent in which the dye is dissolved. When this dispersion is applied onto an ITO film and dried, it is observed with an electron microscope. If the particles have a desired core-shell structure, the shape of the particles can be observed, dissolved and dried. Dye (stain-like) is not observed. In addition, since the absorption of the dye in the solid state is shifted to the shorter wavelength side than the absorption in the dissolved state, the desired core-shell particle can be obtained by measuring the spectrophotometer of the above-mentioned microcapsule particle dispersion and the dye solution. Since the dye does not dissolve, it can be determined whether or not the desired core-shell particles are obtained depending on whether or not the absorption shifts to the long wavelength side.

  In the dye microcapsule according to the present invention, in order to suppress as much as possible the soaking of the dye during long-term storage, the shell portion may be designed to be thick, and in order to increase the absorbability of the dye, the shell portion should be What is necessary is just to design so that it may become thin. Considering the absorption of the dye, it is preferable that 1/3 or more of the particle diameter is the core component.

  Next, a method for producing a dye microcapsule dispersion according to the present invention will be described.

  As a first step, the dye and binder are dissolved in an organic solvent. The organic solvent used preferably dissolves the dye and the binder and has a solubility in pure water of 1% or less. Here, the solubility in the organic solvent is that both the dye and the binder have a certain degree of hardness in water, and it is difficult to finely grind, so that it is easy to disperse (emulsify) by dissolving in the solvent, This is because the shell-forming material or the shell-forming pre-material at the time of encapsulation can be easily adsorbed to the interface, and can be selected by selecting an organic solvent regardless of the dye and binder type.

  The organic solvent that can dissolve the dye and the binder that can be used in the present invention preferably has a boiling point of 120 ° C. or lower and can dissolve the core component by 1% of its own weight. If it satisfies this, it can be used if it is a well-known thing, but it is preferable that the solubility with respect to water is 10% or less.

  Specific organic solvents include, for example, esters such as ethyl acetate and butyl acetate, alicyclic groups such as cyclohexane, aliphatic groups such as heptane and hexane, ketones such as cyclohexanone, alcohols, dimethyl ether, diethyl ether and the like. Examples include ethers, aromatics such as benzene, toluene and xylene, halogenated hydrocarbons such as carbon tetrachloride, chloroform and dichloromethane, diethyl sulfoxide methyl cellosolve, and the like. More than seeds can be used.

  At least a dye and a binder are dissolved in such an organic solvent, and then dispersed in an aqueous solution of a water-soluble resin. Examples of the dispersion include a stirring method using a magnetic stirrer, a dispersion method using a high-speed dissolver, a dispersion method using ultrasonic waves, and a dispersion method using high-pressure shearing such as Manton Gorin and Nanomizer. do it. Among these, from the viewpoint of obtaining dispersed droplets of submicron order, a dispersion method using ultrasonic dispersion or nanomizer is preferable. In particular, ultrasonic dispersion, which is said to be able to form a kind of supercritical state, is preferable. The frequency of the ultrasonic wave to be used is preferably 19 to 22 kHz. At higher frequencies, sub-micron order microcapsules are not used. At frequencies lower than this, the output is too large and difficult to handle, and conversely, agglomeration of dispersed droplets occurs. This may increase the particle size. In order to improve the stability, known anionic surfactants, cationic surfactants, betaine surfactants, nonionic surfactants, fluorosurfactants, etc. may be affected as necessary. You may use in the range which does not give.

  The organic solvent is first removed from the dye microcapsule dispersion thus obtained. The method for removing the organic solvent is not particularly limited, but a method that does not require much heat is preferable from the viewpoint of preventing the decomposition of the dye. Specifically, the dye microcapsule dispersion is removed by reducing the pressure with an evaporator or the like. Is preferred. By the operation of removing the organic solvent, the wall film (shell portion) of the particles is formed. In the formation of the dye microcapsule, a method in which the wall film is not formed prior to the subsequent drying operation, for example, a method of forming a wall film simultaneously with drying using a spray drying method or the like, The particle size is also increased, which is not preferable from the point that submicron order microcapsules cannot be obtained. As a method for forming the wall film, a known method of microencapsulation can be used, but it is particularly preferable to use a simple coacervation method or a complex coacervation method. When the coacervation method uses gelatin and gum arabic as a shell material, it is preferable to use composite coacervation.

  Thereafter, colloidal silica or the like is added. At this time, taking into account the removal after drying due to the submicron particles and the deterioration of the handleability, loose sub-micron aggregates of the submicron particles may be formed by pH control or the like.

  Thereafter, drying is performed to take out the dye microcapsule particles. However, drying is preferably performed under conditions that do not apply heat from the viewpoint of preventing the decomposition of the dye, and is preferably dried with a spray dryer. It is made to dry, controlling the temperature of the powder at the time of drying so that it may become 40 degrees C or less.

  When preparing the light-sensitive material of the present invention, the dye microcapsules according to the present invention are added to the constituent layer coating solution by dispersing in the same organic solvent used in the constituent layer coating solution, Use as a liquid. Further, the fine particles provided with colloidal silica on the surface of the microcapsule particles are dispersed in an organic solvent using a known stirrer such as a magnetic stirrer or dispersed with an ultrasonic wave, and then in the constituent layer coating liquid. Added.

  The coating solution containing the dye microcapsule dispersion thus prepared is coated on the support of the photothermographic material of the present invention. The constituent layer containing the dye microcapsule dispersion according to the present invention can be installed at an arbitrary position, but is particularly preferably provided on the layer between the photosensitive layer and the support or on the back surface side.

[Silver halide grains]
The photosensitive silver halide grains (hereinafter also simply referred to as silver halide grains) used in the silver salt photothermographic dry imaging material of the present invention can inherently absorb light as an intrinsic property of silver halide crystals. When visible light or infrared light can be absorbed by an artificial physicochemical method, and light in any region within the light wavelength range from the ultraviolet light region to the infrared light region is absorbed In addition, the silver halide crystal grains are processed and produced so that physicochemical changes can occur in the silver halide crystals or on the crystal surface.

  The silver halide grains themselves used in the present invention are P.I. Chifie et Physique Photographic (published by Paul Montel, 1967) by Glafkides. F. Duffin's Photographic Emission Chemistry (published by The Focal Press, 1966), V.C. L. It can be prepared as a silver halide grain emulsion using the method described in Making and Coating Photographic Emulsion (published by The Focal Press, 1964) by Zelikman et al. That is, any of an acidic method, a neutral method, an ammonia method, etc. may be used, and the formation of reacting a soluble silver salt and a soluble halogen salt may be any one of a one-side mixing method, a simultaneous mixing method, and a combination thereof. Of these methods, the so-called controlled double jet method, in which silver halide grains are prepared while controlling the formation conditions, is preferred.

  The halogen composition is not particularly limited and may be any of silver chloride, silver chlorobromide, silver chloroiodobromide, silver bromide, silver iodobromide, and silver iodide. Silver chloride or silver iodide is particularly preferred.

  In the case of silver iodobromide, the iodine content is preferably in the range of 0.02 to 16 mol% / Ag mol. Even if iodine is contained so as to be distributed throughout the silver halide grains, the iodine concentration in a specific portion of the silver halide grains, for example, the central portion of the grains is increased, and the concentration in the vicinity of the surface is decreased or substantially reduced. It may be a core / shell structure that is zero.

  Grain formation is usually divided into two stages: silver halide seed grain (nuclear grain) generation and grain growth, and these may be performed continuously at one time, or nucleus (seed grain) formation and grain growth are separated. It is also possible to do this. As the particle forming conditions, a controlled double jet method in which particles are formed by controlling pAg, pH and the like is preferable in that the particle shape and size can be controlled. For example, in the case of a method in which nucleation and grain growth are performed separately, first, a soluble silver salt and a soluble halogen salt are uniformly and rapidly mixed in an aqueous gelatin solution to perform nucleation (nucleation step). Silver halide grains are prepared by a grain growth process in which grains are grown while supplying a soluble silver salt and a soluble halogen salt under controlled pAg, pH, and the like.

  The silver halide grains used in the present invention preferably have a smaller grain size and a mean grain size in order to keep the cloudiness and color tone (yellowishness) after image formation low and to obtain good image quality. As a value when particles having a diameter of less than 0.02 μm are excluded from measurement, 0.030 μm or more and 0.055 μm or less are preferable.

  Here, the grain size refers to the length of the edge of the silver halide grain when the silver halide grain is a so-called normal crystal of a cube or octahedron. Further, when the silver halide grain is a tabular grain, it means the diameter when converted into a circular image having the same area as the projected area of the main surface.

  In the present invention, the silver halide grains are preferably monodispersed. The term “monodispersed” as used herein means that the coefficient of variation of the particle diameter obtained by the following formula is 30% or less. Preferably it is 20% or less, More preferably, it is 15% or less.

Coefficient of variation of particle size = standard deviation of particle size / average value of particle size × 100 (%)
Examples of the shape of the silver halide grains include cubes, octahedrons, tetrahedron grains, tabular grains, spherical grains, rod-shaped grains, and potato grains. Among these, cubic, octahedral, Tetrahedral and tabular silver halide grains are preferred.

  The average aspect ratio when using tabular silver halide grains is preferably 1.5 or more and 100 or less, more preferably 2 or more and 50 or less. These are described in US Pat. Nos. 5,264,337, 5,314,798, 5,320,958, etc., and the desired tabular grains can be easily obtained. Further, grains having rounded corners of silver halide grains can be preferably used.

  The crystal habit on the surface of the silver halide grain is not particularly limited, but when a spectral sensitizing dye having crystal habit (plane) selectivity is used in the adsorption reaction of the sensitizing dye on the surface of the silver halide grain. It is preferable to use silver halide grains having a relatively high proportion of crystal habits adapted to the selectivity. For example, when using a sensitizing dye that is selectively adsorbed on the crystal face of the Miller index [100], the proportion of the [100] face on the outer surface of the silver halide grain is preferably high, and this ratio is 50 % Or more, more preferably 70% or more, and particularly preferably 80% or more. Conversely, when using a sensitizing dye that selectively adsorbs on the crystal face of the Miller index [111], it is preferable to increase the proportion of the [111] face on the outer surface of the silver halide grains. The ratio of the Miller index [100] plane is a T.K. based on the adsorption dependency of the [111] plane and the [100] plane in the adsorption of the sensitizing dye. Tani, J .; Imaging Sci. 29, 165 (1985).

  The silver halide grains used in the present invention are preferably prepared using low molecular weight gelatin having an average molecular weight of 50,000 or less at the time of grain formation, and particularly preferably used at the time of nucleation of silver halide grains. The low molecular weight gelatin has an average molecular weight of 50,000 or less, preferably 2000 to 40000, more preferably 5000 to 25000. The average molecular weight of gelatin can be measured by gel filtration chromatography.

  The concentration of the dispersion medium at the time of nucleation is preferably 5% by mass or less, and more effective at a low concentration of 0.05 to 3.0% by mass.

  As the silver halide grains used in the present invention, a polyethylene oxide compound represented by the following general formula can be used at the time of grain formation.

Formula _{YO (CH 2 CH 2 O)} m (CH (CH 3) CH 2 O) p (CH 2 CH 2 O) n Y
In the formula, Y represents a hydrogen atom, —SO ₃ M, or —CO—B—COOM, and M represents an ammonium group substituted with a hydrogen atom, an alkali metal atom, an ammonium group, or an alkyl group having 5 or less carbon atoms. And B represents a chain or cyclic group forming an organic dibasic acid. m and n each represents 0 to 50, and p represents 1 to 100.

  The polyethylene oxide compound represented by the above general formula is used in the production of a light-sensitive material in which a gelatin aqueous solution is produced, a water-soluble halide and a water-soluble silver salt are added to the gelatin solution, and a silver halide emulsion is supported. It has been preferably used as an antifoaming agent for significant foaming when the emulsion raw material is stirred or moved, such as a coating step, and the technology used as the antifoaming agent is, for example, JP-A-44. No. 9497, the polyethylene oxide compound represented by the above general formula also functions as an antifoaming agent during nucleation.

  The polyethylene oxide compound represented by the above general formula is preferably used in an amount of 1% by mass or less, more preferably 0.01 to 0.1% by mass with respect to silver.

  The polyethylene oxide compound represented by the above general formula may be present at the time of nucleation and is preferably added in advance to the dispersion medium before nucleation, but may be added during nucleation, You may add and use for the silver salt aqueous solution and halide aqueous solution which are used at the time of nucleation. Preferably, it is used by adding 0.01 to 2.0% by mass to the aqueous halide solution or both aqueous solutions. Further, it is preferably present for a time of at least 50% of the nucleation step, more preferably for a time of 70% or more. The polyethylene oxide compound represented by the above general formula may be added as a powder or dissolved in a solvent such as methanol.

  The temperature at the time of nucleation is 5 to 60 ° C., preferably 15 to 50 ° C. Even if the temperature is constant, the temperature rising pattern (for example, the temperature at the start of nucleation is 25 ° C. It is preferable to control the temperature within the above temperature range even when the temperature is gradually raised and the temperature at the end of nucleation is 40 ° C.) and vice versa.

The concentration of the silver salt aqueous solution and halide aqueous solution used for nucleation is preferably 3.5 mol / L or less, and more preferably used in a low concentration range of 0.01 to 2.5 mol / L. The addition rate of silver ions during nucleation is preferably 1.5 × 10 ^{−3 to} 3.0 × 10 ⁻¹ mol / min, more preferably 3.0 × 10 ^{−3 to} 8.0, per liter of the reaction solution. × 10 ^-2 mol / min.

  The pH at the time of nucleation can be set in the range of 1.7 to 10, but the pH on the alkali side is preferably 2 to 6 in order to broaden the particle size distribution of nuclei to be formed. Moreover, pBr at the time of nucleation is about 0.05 to 3.0, preferably 1.0 to 2.5, and more preferably 1.5 to 2.0.

[Inner latent type silver halide grains after heat development according to the present invention]
The photosensitive silver halide grain according to the present invention is a silver halide grain whose surface sensitivity is lowered by converting from a surface latent image type to an internal latent image type by thermal development. That is, in the exposure before thermal development, a latent image that can function as a catalyst for a development reaction (reduction reaction of silver ions by a silver ion reducing agent) is formed on the surface of the silver halide grains, and the exposure after the thermal development process has passed. Then, since many latent images are formed inside the surface of the silver halide grains, the silver halide grains are characterized in that the formation of latent images on the surface is suppressed. In addition, it has not been conventionally known that silver halide grains whose latent image forming function greatly changes before and after heat development are used for dry imaging materials.

  In general, when photosensitive silver halide grains are exposed, the silver halide grains themselves or spectral sensitizing dyes adsorbed on the surface of the photosensitive silver halide grains are photoexcited to freely move electrons. Although generated, these electrons are competitively trapped (captured) by an electron trap (photosensitive center) existing on the surface of the silver halide grain or an electron trap inside the silver halide grain. Therefore, when there are more and appropriate numbers of chemical sensitization centers (chemical sensitization nuclei) and dopants effective as electron traps on the surface than inside the silver halide grain, a latent image is preferentially formed on the grain surface, Development is possible. Conversely, if there are more chemical sensitization centers (chemical sensitization nuclei) and dopants that are effective as electron traps in the interior than the surface of the silver halide grains, and there are an appropriate number of them, a latent image is preferentially formed inside. , Surface development becomes difficult. In other words, in the former case, the surface sensitivity is higher than in the interior, and in the latter case, it can be said that the surface sensitivity is lower than in the interior (reference: (1) edited by TH James “The Theory of the Photographic Process”. "4th edition, Macmillan Publishing Co., Ltd. 1977, (2) Revised edition of the Japan Photography Society" Basics of Photographic Engineering (Silver Salt Photography) ", Corona, 1998).

  In the photosensitive silver halide grain according to the present invention, it is preferable in terms of sensitivity and image storage stability to contain a dopant functioning as an electron trapping dopant at least during exposure after heat development. .

  In addition, a dopant that functions as a hole trap during the exposure for image formation before heat development, changes in the heat development process, and functions as an electron trap after heat development, Particularly preferred.

  The electron trapping dopant used here is an element or compound other than silver and halogen constituting silver halide grains, and the dopant itself has a property of trapping (capturing) free electrons, or the dopant is halogen. It is the one in which a site such as an electron trapping lattice defect is generated by being contained in a silver halide grain. For example, metal ions other than silver or salts or complexes thereof, chalcogens (oxygen group elements) such as sulfur, selenium, tellurium, or inorganic compounds or organic compounds containing nitrogen atoms, or metal complexes thereof, rare earth ions or complexes thereof, etc. Can be mentioned.

  Examples of metal ions or salts or complexes thereof include lead ions, bismuth ions, gold ions, etc., or lead bromide, lead nitrate, lead carbonate, lead sulfate, bismuth nitrate, bismuth chloride, bismuth trichloride, bismuth carbonate, sodium bismutate, Examples include chloroauric acid, lead acetate, lead stearate, and bismuth acetate.

  As the compound containing a chalcogen such as sulfur, selenium or tellurium, various chalcogen-releasing compounds generally known as chalcogen sensitizers in the photographic industry can be used. Moreover, as an organic substance containing chalcogen or nitrogen, a heterocyclic compound is preferable. For example, imidazole, pyrazole, pyridine, pyrimidine, pyrazine, pyridazine, triazole, triazine, indazole, purine, thiadiazole, oxadiazole, quinoline, phthalazine, naphthyridine, quinoxaline, quinazoline, cinnoline, pteridine, acridine, phenanthroline, phenazine, Tetrazole, thiazole, oxazole, benzimidazole, benzoxazole, benzthiazole, indolenine, tetrazaindene, preferably imidazole, pyridine, pyrimidine, pyrazine, pyridazine, triazole, triazine, thiadiazole, oxadiazole, quinoline, phthalazine, Naphthyridine, quinoxaline, quinazoline, cinnoline, tetrazole, thiazole, o Sasol, benzimidazole, benzoxazole, benzthiazole, a tetrazaindene.

  The above heterocyclic compound may have a substituent, and the alkyl group, alkenyl group, aryl group, alkoxy group, aryloxy group, acyloxy group, acyl group, alkoxycarbonyl group are preferable as the substituent. Aryloxycarbonyl group, acyloxy group, acylamino group, alkoxycarbonylamino group, aryloxycarbonylamino group, sulfonylamino group, sulfamoyl group, carbamoyl group, sulfonyl group, ureido group, phosphoric acid amide group, halogen atom, cyano group, Sulfo group, carboxyl group, nitro group and heterocyclic group, more preferably alkyl group, aryl group, alkoxy group, aryloxy group, acyl group, acylamino group, alkoxycarbonylamino group, aryloxycarbonylamino group, sulfonyl group Amino group, sulfamoyl group, carbamoyl group, ureido group, phosphoric acid amide group, halogen atom, cyano group, nitro group, heterocyclic group, more preferably alkyl group, aryl group, alkoxy group, aryloxy group, acyl group An acylamino group, a sulfonylamino group, a sulfamoyl group, a carbamoyl group, a halogen atom, a cyano group, a nitro group, or a heterocyclic group.

  The silver halide grains used in the present invention include those from Group 6 of the Periodic Table of Elements so that they function as electron trapping dopants as described above or as hole trapping dopants. Transition metal ions belonging to Group 11 may be contained by chemically adjusting the oxidation state of the metal with a ligand. As the transition metal, W, Fe, Co, Ni, Cu, Ru, Rh, Pd, Re, Os, Ir, and Pt are preferable.

  In the present invention, the above various dopants may be used alone or in combination of two or more of the same or different compounds or complexes. However, at least one kind needs to function as an electron trapping dopant at the time of exposure after thermal development. These dopants may be introduced into the silver halide grains in any chemical form.

  In the present invention, an embodiment in which any one of Ir or Cu complex or salt is used alone is not preferable.

The preferable content of the dopant is preferably in the range of 1 × 10 ⁻⁹ to 10 mol, more preferably in the range of 1 × 10 ⁻⁸ to 1 × 10 ⁻¹ mol, with ^respect to 1 mol of silver. Furthermore, 1 * 10 ^{< -6} > ^-1 * 10 ^<-2> mol is preferable.

  However, since the optimum amount depends on the kind of dopant, the grain size and shape of the silver halide grains, and other environmental conditions, it is preferable to examine optimization of the dopant addition conditions according to these conditions.

  In the present invention, the transition metal complex or complex ion is preferably represented by the following general formula.

General formula [ML ₆ ] ^m
In the formula, M represents a transition metal selected from Group 6 to Group 11 elements of the periodic table, L represents a ligand, and m represents 0,-, 2-, 3-, or 4-. Specific examples of the ligand represented by L include halogen ions (for example, fluorine ion, chlorine ion, bromine ion, iodine ion), cyanide, cyanate, thiocyanate, selenocyanate, tellurocyanate, azide and aquo. Each ligand includes nitrosyl, thionitrosyl, and the like, preferably aco, nitrosyl, thionitrosyl, and the like. When an acoligand is present, it preferably occupies one or two of the ligands. L may be the same or different.

  The compounds providing these metal ions or complex ions are preferably added during silver halide grain formation and incorporated into the silver halide grains. Preparation of silver halide grains, that is, nucleation, growth, physical ripening In addition, it may be added at any stage before or after chemical sensitization, but it is particularly preferably added at the stage of nucleation, growth and physical ripening, and more preferably at the stage of nucleation and growth, Most preferably, it is added at the stage of nucleation. In addition, it may be divided and added several times, and can be uniformly contained in the silver halide grains. For example, JP-A-63-29603, JP-A-2-306236, 3 As described in JP-A Nos. 167545, 4-76534, 6-110146, 5-273683, etc., the particles can be contained with a distribution.

  These metal compounds can be added by dissolving in water or an appropriate organic solvent (for example, alcohols, ethers, glycols, ketones, esters, amides). A method in which an aqueous solution or an aqueous solution in which a metal compound is dissolved together with NaCl and KCl is added to a water-soluble silver salt solution or a water-soluble halide solution during particle formation, or a silver salt solution and a halide solution are mixed simultaneously. When adding a third aqueous solution, a method of preparing silver halide grains by a method of simultaneous mixing of three solutions, a method of adding an aqueous solution of a required amount of a metal compound to a reaction vessel during grain formation, or a preparation of silver halide There is a method of adding and dissolving another silver halide grain which has been previously doped with metal ions or complex ions. In particular, a method of adding an aqueous solution of a metal compound powder or an aqueous solution in which a metal compound and NaCl, KCl are dissolved together is added to the water-soluble halide solution. When added to the particle surface, a required amount of an aqueous solution of a metal compound can be charged into the reaction vessel immediately after the formation of the particle, during or after physical ripening, or at the time of chemical ripening.

  In addition, a nonmetallic dopant can also be introduce | transduced inside a silver halide by the method similar to said metallic dopant.

  In the light-sensitive material of the present invention, whether or not the above dopant has an electron trapping property can be evaluated by a method generally used in the photographic industry as follows. That is, a silver halide emulsion comprising silver halide grains doped with the above-mentioned dopant or a decomposition product thereof in silver halide grains is subjected to a photoconductivity measurement by a microwave photoconductivity measurement method or the like, and the halogenation does not contain a dopant. It can be evaluated by measuring the degree of decrease in photoconduction based on a silver grain emulsion. Alternatively, it can be performed by a comparative experiment of the internal sensitivity and surface sensitivity of the silver halide grains.

  Alternatively, a method for evaluating the effect of the electron trapping dopant according to the present invention after preparing a photothermographic dry imaging material is, for example, heating the imaging material under the same conditions as normal practical thermal development conditions before exposure. After that, for a certain period of time (for example, 30 seconds), white light or light in a specific spectral sensitization region (when spectral sensitization is performed on laser light in a specific wavelength region, For example, when spectral sensitization is applied to infrared light, the vertical axis obtained by exposing the infrared light) through an optical wedge and further thermally developing under the same thermal development conditions is the image density (D). The sensitivity obtained on the basis of a characteristic curve (sensitometry curve) consisting of the exposure dose (E) on the horizontal axis represents the sensitivity of an imaging material using a silver halide grain emulsion not containing the electron trapping dopant. It can be evaluated by comparison. That is, it is necessary to confirm that the sensitivity of the former sample containing the silver halide grain emulsion containing the dopant according to the present invention is lower than the sensitivity of the latter sample not containing the dopant.

In the light-sensitive material of the present invention, white light or light in a specific spectrally sensitized region (for example, infrared light) is exposed through an optical wedge at a constant exposure time (for example, 30 seconds), and normal practical heat development is performed. after the heat development in conditions, the sensitivity obtained on the basis of the characteristic curve and S _1, pre-exposure to heat treatment under the same conditions as said actual for thermal development conditions, then at a certain exposure time, white light or specific spectral sensitizers S ₂ / S ₁ is 0.1 or less when the sensitivity obtained based on the characteristic curve is S ₂ after exposure of light in the sensitive region through an optical wedge and further heat development under the practical heat development conditions. It is preferably 1/10 or less, more preferably 0.05 or less (1/20 or less), and when the silver halide emulsion is further chemically sensitized, more preferably 0.02 or less ( 1/50 or less).

  The silver halide grains according to the present invention may be added to the photosensitive layer by any method, and at this time, the silver halide grains are arranged so as to be close to a reducible silver source (aliphatic carboxylic acid silver salt). This is preferable for obtaining a photosensitive material having high sensitivity and high covering power (CP).

  It is possible to prepare silver halide grains according to the present invention in advance and add them to a solution for preparing aliphatic carboxylic acid silver salt grains to prepare a silver halide grain preparation step and aliphatic carboxylic acid silver salt grains. The preparation process can be handled separately, and is most preferable in terms of production control. However, as described in British Patent No. 1,447,454, when preparing aliphatic carboxylic acid silver salt particles, halide ions, etc. It is also possible to use silver halide grains formed at almost the same time as the formation of the aliphatic carboxylate silver salt grains by injecting silver ions into the aliphatic carboxylate silver salt-forming ingredient. it can. It is also possible to prepare a silver halide grain by converting a halogen-containing silver salt to an aliphatic carboxylic acid silver salt and converting the aliphatic carboxylic acid silver salt, and use the grain together. That is, a silver halide-forming component is allowed to act on a solution or dispersion of an aliphatic carboxylic acid silver salt prepared in advance, or a sheet material containing the aliphatic carboxylic acid silver salt, so that a part of the aliphatic carboxylic acid silver salt is removed. It can also be converted to photosensitive silver halide.

  Examples of the silver halide grain forming component include inorganic halogen compounds, onium halides, halogenated hydrocarbons, N-halogen compounds, and other halogen-containing compounds. Specific examples thereof are US Pat. No. 4,009,039. No. 3,457,075, No. 4,003,749, British Patent No. 1,498,956 and JP-A-53-27027, No. 53-25420.

  You may use together the silver halide grain manufactured by converting a part of aliphatic carboxylic acid silver salt into the silver halide grain separately prepared as mentioned above.

  These silver halide grains are separately prepared silver halide grains, 0.001 to 0.7 mol per 1 mol of aliphatic carboxylic acid silver salt, and silver halide grains obtained by conversion of aliphatic carboxylic acid silver salt. Preferably it is used at 0.03-0.5 mol.

  Separately prepared photosensitive silver halide grains are desalted by a known desalting method such as noodle method, flocculation method, ultrafiltration method, electrodialysis method, etc. However, it can be used without desalting.

[Chemical sensitization]
The photosensitive silver halide grains according to the present invention can be chemically sensitized. For example, use of a compound that releases a chalcogen such as sulfur, selenium, tellurium, or a noble metal ion that releases a noble metal ion such as gold ion by the methods described in JP-A Nos. 2001-249428 and 2001-249426 Thus, it is possible to form and impart a chemical sensitization center (chemical sensitization nucleus) capable of capturing electrons or holes generated by photoexcitation of photosensitive silver halide grains or spectral sensitizing dyes on the grains. In particular, it is preferably chemically sensitized with an organic sensitizer containing a chalcogen atom.

  These organic sensitizers containing chalcogen atoms are preferably compounds having groups capable of adsorbing to silver halide and unstable chalcogen atom sites.

  These organic sensitizers are disclosed in JP-A-60-150046, JP-A-4-109240, JP-A-11-218874, JP-A-11-218875, JP-A-11-218876, JP-A-11-194447, etc. The organic sensitizers having various structures can be used, and among them, the chalcogen atom is at least one kind of compound having a structure in which a carbon atom or a phosphorus atom is bonded with a double bond It is preferable. In particular, a thiourea derivative having a heterocyclic group and a triphenylphosphine sulfide derivative are preferred.

  As a method for chemical sensitization, techniques according to various chemical sensitization techniques conventionally used in the production of conventional silver halide light-sensitive materials for wet processing can be used (reference: (1) T Edited by H. James “The Theory of the Photographic Process” 4th edition, Macmillan Publishing Co., Ltd. 1977, “Photographic Engineering Fundamentals (Silver Salt Photography)”, Corona, 1979 ). In particular, when the silver halide grain emulsion is previously chemically sensitized and then mixed with non-photosensitive organic silver salt grains, it can be chemically sensitized by a conventional method.

The amount of a chalcogen compound added as an organic sensitizer is chalcogen compound to be used, silver halide grains will vary due reaction environment when subjected to chemical sensitization, generally, per mol of silver halide, 1 × 10 ^{- It} is preferably ⁸ to 1 × 10 ⁻² mol, more preferably 1 × 10 ⁻⁷ to 1 × 10 ⁻³ mol. The environmental conditions for chemical sensitization are not particularly limited, but in the presence of a compound capable of annihilating or reducing the size of silver chalcogenide or silver nuclei on the photosensitive silver halide grains, and In particular, it may be preferable to perform chalcogen sensitization using an organic sensitizer containing a chalcogen atom in the presence of an oxidizing agent capable of oxidizing silver nuclei. In this case, the sensitizing condition is preferably 6 to 11 as pAg, more preferably 7 to 10, pH 4 to 10, more preferably 5 to 8, and the temperature is increased at 30 ° C. or less. It is preferable to give a feeling.

  In addition, chemical sensitization using these organic sensitizers is preferably performed in the presence of a heteroatom-containing compound having adsorptivity to spectral sensitizing dyes or silver halide grains. By performing chemical sensitization in the presence of a compound having an adsorptivity to silver halide, dispersion of the chemical sensitization central core can be prevented, and high sensitivity and low fog can be achieved. Although the spectral sensitizing dye will be described later, preferred examples of the heteroatom-containing compound having adsorptivity to silver halide include nitrogen-containing heterocyclic compounds described in JP-A-3-24537. In the nitrogen-containing heterocyclic compound, examples of the heterocyclic ring include pyrazole ring, pyrimidine ring, 1,2,4-triazole ring, 1,2,3-triazole ring, 1,3,4-thiadiazole ring, 1,2 , 3-thiadiazole ring, 1,2,4-thiadiazole ring, 1,2,5-thiadiazole ring, 1,2,3,4-tetrazole ring, pyridazine ring, 1,2,3-triazine ring, these rings Can be mentioned, for example, a triazolotriazole ring, a diazaindene ring, a triazaindene ring, a pentaazaindene ring, and the like. A heterocyclic ring in which a monocyclic heterocyclic ring and an aromatic ring are condensed, for example, a phthalazine ring, a benzimidazole ring, an indazole ring, a benzthiazole ring, or the like can also be applied.

  Of these, an azaindene ring is preferable, and an azaindene compound having a hydroxyl group as a substituent, for example, a hydroxytriazaindene, tetrahydroxyazaindene, hydroxypentaazaindene compound, or the like is more preferable.

  The heterocyclic ring may have a substituent other than the hydroxyl group. Examples of the substituent include an alkyl group, a substituted alkyl group, an alkylthio group, an amino group, a hydroxyamino group, an alkylamino group, a dialkylamino group, an arylamino group, a carboxyl group, an alkoxycarbonyl group, a halogen atom, and a cyano group. You may have.

The amount of the heterocyclic compound added varies over a wide range depending on the size, composition, and other conditions of the silver halide grains, but the approximate amount is from 1 × 10 ⁻⁶ to 1 × 10 ⁻⁶ to 1 mol of silver halide. The range is 1 mol, and preferably 1 × 10 ⁻⁴ to 1 × 10 ⁻¹ mol.

  The photosensitive silver halide according to the present invention can be subjected to noble metal sensitization using a compound that releases noble metal ions such as gold ions. For example, a chloroaurate or an organic gold compound can be used as a gold sensitizer. The gold sensitization technique disclosed in JP-A-11-194447 is useful as a reference.

  In addition to the above-described sensitization methods, reduction sensitization methods and the like can also be used. Examples of reduction sensitization shell-like compounds include ascorbic acid, thiourea dioxide, stannous chloride, hydrazine derivatives, A borane compound, a silane compound, a polyamine compound, or the like can be used. Further, reduction sensitization can be performed by ripening the emulsion while maintaining the pH at 7 or higher or the pAg at 8.3 or lower.

  In the present invention, the silver halide grains subjected to chemical sensitization may be formed in the presence of an aliphatic carboxylic acid silver salt, or in the absence of the organic silver salt, A mixture of the two may be used.

  In the present invention, when the surface of the photosensitive silver halide grain is chemically sensitized, it is necessary that the chemical sensitization effect substantially disappears after the thermal development process. Here, the fact that the effect of chemical sensitization substantially disappears means that the sensitivity of the photosensitive material obtained by the above-described chemical sensitization technique is 1.1 or less of the sensitivity when chemical sensitization is not performed after the thermal development process. Say to decrease. In order to eliminate the chemical sensitization effect in the heat development process, an oxidant capable of destroying the chemical sensitization center (chemical sensitization nucleus) by an oxidation reaction at the time of heat development, for example, the above-mentioned halogen radical releasing compound, etc. It is necessary to contain an appropriate amount of the above in the photosensitive layer and / or the non-photosensitive layer of the imaging material. The content of the oxidizing agent is preferably adjusted in consideration of the oxidizing power of the oxidizing agent, the reduction range of the chemical sensitization effect, and the like.

[Spectral sensitization]
The photosensitive silver halide in the present invention is preferably subjected to spectral sensitization by adsorbing a spectral sensitizing dye. As spectral sensitizing dyes, cyanine dyes, merocyanine dyes, complex cyanine dyes, complex merocyanine dyes, holopolar cyanine dyes, styryl dyes, hemicyanine dyes, oxonol dyes, hemioxonol dyes and the like can be used. For example, JP-A-63-159841, JP-A-60-140335, JP-A-63-231437, JP-A-63-259651, JP-A-63-304242, JP-A-63-15245, US Pat. No. 4,639,414, No. 4,740,455, No. 4,741,966, No. 4,751,175, No. 4,835,096 can be used.

  Useful sensitizing dyes used in the present invention include, for example, Research Disclosure (hereinafter abbreviated as RD) 17643IV-A (December 1978 p.23), RD18431X (August 1978 p.437). It is described in the literature described or cited. In particular, it is preferable to use a sensitizing dye having a spectral sensitivity suitable for the spectral characteristics of the light sources of various laser imagers and scanners. For example, compounds described in JP-A Nos. 9-34078, 9-54409, and 9-80679 are preferably used.

  Useful cyanine dyes are, for example, cyanine dyes having basic nuclei such as thiazoline nucleus, oxazoline nucleus, pyrroline nucleus, pyridine nucleus, oxazole nucleus, thiazole nucleus, selenazole nucleus and imidazole nucleus. Useful merocyanine dyes are preferably acidic nuclei such as thiohydantoin nucleus, rhodanine nucleus, oxazolidinedione nucleus, thiazolinedione nucleus, barbituric acid nucleus, thiazolinone nucleus, malononitrile nucleus and pyrazolone nucleus in addition to the basic nuclei described above. Including.

  In the present invention, a sensitizing dye having spectral sensitivity particularly in the infrared can also be used. Examples of infrared spectral sensitizing dyes preferably used include infrared spectral sensitization disclosed in US Pat. Nos. 4,536,473, 4,515,888, 4,959,294, and the like. Examples include dyes.

  In the silver salt photothermographic dry imaging material according to the present invention, the sensitizing dye represented by the following general formula (SD-1) as described in Japanese Patent Application No. 2003-102726 and the following general formula (SD-2) It is preferable to contain at least one selected from sensitizing dyes represented by

In the formula, Y ₁ and Y ₂ each represent an oxygen atom, a sulfur atom, a selenium atom, or a —CH═CH— group, and L _{1 to} L ₉ each represent a methine group. R ₁ and R ₂ each represents an aliphatic group. R ₃ , R ₄ , R ₂₃ and R ₂₄ each represent a lower alkyl group, a cycloalkyl group, an alkenyl group, an aralkyl group, an aryl group, or a heterocyclic group. W ₁ , W ₂ , W ₃ , and W ₄ are each a hydrogen atom, a substituent, or a nonmetallic atom necessary for bonding between W ₁ and W ₂ , W ₃ and W ₄ to form a condensed ring. Represents a group. Or R ₃ and W ₁ , R ₃ and W ₂ , R ₂₃ and W ₁ , R ₂₃ and W ₂ , R ₄ and W ₃ , R ₄ and W ₄ , R ₂₄ and W ₃ , R ₂₄ and W ₄ Represents a group of non-metallic atoms necessary to form a 5-membered or 6-membered condensed ring by bonding. X ₁ represents an ion necessary for canceling the charge in the molecule, and k 1 represents the number of ions necessary for canceling the charge in the molecule. m1 represents 0 or 1. n1 and n2 each represents 0, 1 or 2. However, n1 and n2 are not 0 at the same time.

  The above-mentioned infrared sensitizing dyes are described in, for example, The Chemistry of Heterocyclic Compounds, Volume 18 by The FM Hammer, The Cyanine Dies and Related Compounds (A. Weissberger ed. It can be easily synthesized by this method.

  These infrared sensitizing dyes may be added at any time after the silver halide is prepared. For example, silver halide grains or halogens may be added in a so-called solid dispersion state added to a solvent or dispersed in a fine particle form. It can be added to a light-sensitive emulsion containing silver halide grains / aliphatic carboxylic acid silver salt grains. Similarly to the heteroatom-containing compound having adsorptivity to the silver halide grains, chemical sensitization can be performed after being added to and adsorbed to the silver halide grains prior to chemical sensitization. Thus, dispersion of the chemical sensitization central core can be prevented, and high sensitivity and low fog can be achieved.

  In the present invention, one kind of spectral sensitizing dye may be used alone, but as described above, it is preferable to use a combination of plural kinds of spectral sensitizing dyes. The combination is often used for the purpose of supersensitization and enlargement or adjustment of the photosensitive wavelength region.

  The emulsion containing the photosensitive silver halide and the aliphatic carboxylic acid silver salt used in the silver salt photothermographic dry imaging material of the present invention is not only a sensitizing dye but also a dye having no spectral sensitizing action itself or visible light. In the emulsion, a substance that does not substantially absorb the color and expresses a supersensitization effect may be contained in the emulsion, whereby the silver halide grains may be supersensitized.

  Useful sensitizing dyes, combinations of dyes exhibiting supersensitization, and substances exhibiting supersensitization are described in Research Disclosure (hereinafter abbreviated as RD) 17643 (issued in December, 1978), Section J, Item IV. Or JP-B-9-25500, JP-A-43-4933, JP-A-59-19032, JP-A-59-192242, JP-A-5-341432, and the like. A heteroaromatic mercapto compound represented by the following or a mercapto derivative compound is preferred.

Ar-SM
In the formula, M is a hydrogen atom or an alkali metal atom, and Ar is an aromatic ring or condensed aromatic ring having one or more nitrogen, sulfur, oxygen, selenium, or tellurium atoms. Preferably, the heteroaromatic ring is benzimidazole, naphthimidazole, benzthiazole, naphthothiazole, benzoxazole, naphthoxazole, benzselenazole, benztelrazole, imidazole, oxazole, pyrazole, triazole, triazine, pyrimidine, pyridazine, pyrazine, pyridine , Purine, quinoline, or quinazoline. However, other heteroaromatic rings are also included.

  In addition, mercapto derivative compounds that substantially produce the above mercapto compounds when included in a dispersion of an aliphatic carboxylic acid silver salt or silver halide grain emulsion are also included. In particular, mercapto derivative compounds represented below are preferred examples.

Ar-SS-Ar
Ar in the formula has the same meaning as in the case of the mercapto compound represented above.

  The heteroaromatic ring includes, for example, a halogen atom (for example, chlorine, bromine, iodine), a hydroxyl group, an amino group, a carboxyl group, and an alkyl group (for example, one or more carbon atoms, preferably 1 to 4 carbon atoms). It may have a substituent selected from the group consisting of those having a carbon atom) and alkoxy groups (for example, those having 1 or more carbon atoms, preferably 1 to 4 carbon atoms).

  In addition to the above supersensitizers, macrocycles having heteroatoms disclosed in JP-A-2001-330918 can also be used as supersensitizers.

  The supersensitizer according to the present invention is preferably used in an amount of 0.001 to 1.0 mol per mol of silver in a photosensitive layer containing an organic silver salt and silver halide grains. Particularly preferred is an amount of 0.01 to 0.5 mole per mole of silver.

  In the present invention, it is preferable that spectral sensitizing dye is adsorbed on the surface of the photosensitive silver halide grains to perform spectral sensitization, and that the spectral sensitizing effect is substantially lost after the thermal development process. Here, the spectral sensitization effect substantially disappears when the sensitivity of the light-sensitive material obtained with a sensitizing dye, supersensitizer or the like is 1. Say to decrease to 1 times or less.

  In order to eliminate the spectral sensitizing effect in the thermal development process, use a spectral sensitizing dye that is easily detached from the silver halide grains by heat during thermal development or / and destroy the spectral sensitizing dye by an oxidation reaction. It is necessary that an appropriate amount of an oxidizing agent that can be used, for example, the above-mentioned halogen radical releasing compound is contained in the emulsion layer and / or the non-photosensitive layer of the imaging material. The content of the oxidizing agent is preferably adjusted in consideration of the oxidizing power of the oxidizing agent, the reduction range of the spectral sensitization effect, and the like.

[Non-photosensitive aliphatic carboxylic acid silver salt]
The non-photosensitive aliphatic carboxylic acid silver salt according to the present invention is a reducible silver source, and a silver salt of a long-chain aliphatic carboxylic acid having 10 to 30, preferably 15 to 25 carbon atoms is preferable. Examples of suitable silver salts include the following.

  Examples thereof include silver salts such as gallic acid, succinic acid, behenic acid, stearic acid, arachidic acid, palmitic acid and lauric acid, and preferable silver salts include silver behenate, silver arachidate and silver stearate.

  In the present invention, it is preferable that two or more kinds of aliphatic carboxylic acid silver salts are mixed in order to improve developability and form a silver image having a high density and a high contrast. It is preferable to prepare by mixing a silver ion solution with an aromatic carboxylic acid mixture.

  On the other hand, from the viewpoint of the storage stability of the image after development, the melting point of the aliphatic carboxylic acid which is a raw material for the aliphatic carboxylate silver is 50 ° C or higher, preferably 60 ° C or higher. The content ratio is preferably 50% or more, preferably 70% or more, and more preferably 80% or more. From this viewpoint, specifically, it is preferable that the content of silver behenate is high.

  The aliphatic carboxylic acid silver salt is obtained by mixing a water-soluble silver compound and a compound that forms a complex with silver, and is described in Japanese Patent Application Laid-Open No. 9-127643. The controlled double jet method as described above is preferably used. For example, an alkali metal salt (eg, sodium hydroxide, potassium hydroxide, etc.) is added to an organic acid to produce an organic acid alkali metal salt soap (eg, sodium behenate, sodium arachidate), and then a controlled double jet. According to the method, the soap and silver nitrate are mixed to produce an aliphatic carboxylic acid silver salt crystal. At that time, seed crystal grains of silver aliphatic carboxylate, silver halide grains, and the like may be mixed.

  Examples of the alkali metal salt used in the present invention include sodium hydroxide, potassium hydroxide, and lithium hydroxide, but it is preferable to use sodium hydroxide and potassium hydroxide in combination. The combined ratio is preferably such that the molar ratio of both of the above-mentioned hydroxide salts is in the range of 10:90 to 75:25. When used in the above range when reacted with an aliphatic carboxylic acid to form an alkali metal salt of an aliphatic carboxylic acid, the viscosity of the reaction solution can be controlled in a good state.

  In addition, when preparing an aliphatic carboxylate silver salt in the presence of silver halide grains having an average particle diameter of 0.050 μm or less, the alkali metal of the alkali metal salt is preferably a halide having a higher potassium ratio. It is preferable because dissolution of silver particles and Ostwald ripening are prevented. Moreover, the size of fatty acid silver salt particle | grains can be made small, so that the ratio of potassium salt is high. A preferable ratio of the potassium salt is 50 to 100% based on the total alkali metal salt used in the step of producing the aliphatic carboxylate. The concentration of the alkali metal salt is preferably 0.1 to 0.3 mol / 1000 ml.

[Anti-fogging agent and image stabilizer]
As described above, compared to conventional silver halide photographic light-sensitive materials, the biggest difference in the composition of silver salt photothermographic dry imaging materials is that fog and print-out silver (printing) are performed before and after the development process. A large amount of photosensitive silver halide, an organic silver salt and a reducing agent that may cause the occurrence of silver). For this reason, advanced antifogging and image stabilization techniques are essential for silver salt photothermographic dry imaging materials to maintain storage stability not only before development but also after development. In addition to aromatic heterocyclic compounds that suppress development, mercury compounds such as mercury acetate, which have the function of oxidizing and extinguishing fog nuclei, have been used as very effective storage stabilizers. The use of compounds has been a problem in terms of safety and environmental conservation.

  Regarding the technology for preventing fogging and stabilizing the image, basically, the silver ions or metal silver is prevented from being reduced by the silver ions being reduced during storage before and after development. It is also important to consider the fact that the generated silver (metal silver) is oxidized and disappeared, or that metal silver prevents its function as a catalyst for the reaction of reducing silver ions. It is done.

  Hereinafter, the anti-fogging and image stabilizer suitably used for the silver salt photothermographic dry imaging material of the present invention will be described.

  In the silver salt photothermographic dry imaging material of the present invention, it is preferable to mainly use bisphenols as the silver ion reducing agent, as described later, and the storage conditions before development of the silver salt photothermographic dry imaging material And a compound capable of inactivating the reducing agent under storage conditions after heat development. Preferably, a compound that can prevent the generation of a phenoxyl radical from a reducing agent or a compound that can trap the generated phenoxyl radical and stabilize it so as not to function as a silver ion reducing agent is preferable. . Suitable compounds having such functions and functions include non-reducing compounds having a group capable of forming a hydrogen bond with the hydroxyl group of bisphenols, such as phosphoryl group, sulfoxide group, sulfonyl group, carbonyl group, amide And compounds having a group, an ester group, a urethane group, a ureido group, a tertiary amino group, a nitrogen-containing aromatic group, and the like. Particularly preferred are compounds having a sulfonyl group, a sulfoxide group, or a phosphoryl group. Specific examples are disclosed in JP-A-6-208192, JP-A-2001-215648, JP-A-350235, JP-A-2002-6444, JP-A-2002-18264, and the like. Further, specific compounds having a vinyl group are disclosed in JP-T-2000-515995, JP-A-2002-207273, JP-A-2003-140298, and the like.

  Also used in combination with compounds that can oxidize silver (metal silver), for example, compounds that can oxidize silver by releasing an oxidizing halogen radical or interacting with silver to form a charge transfer complex can do. Specific examples of compounds having such functions include JP-A-50-120328, JP-A-59-57234, JP-A-4-232939, JP-A-6-208193, JP-A-10-197989, and the United States. Japanese Patent No. 5,460,938, Japanese Patent Laid-Open No. 7-2781, and the like.

  In particular, in the imaging material according to the present invention, specific examples of preferable compounds include halogen radical releasing compounds that can be represented by the following general formula (OFI).

General formula (OFI)
_{Q 2 -Y-C (X 1} ) (X 3) (X 2)
In the above general formula (OFI), Q ₂ represents an aryl group or a heterocyclic group. X ₁ , X ₂ and X ₃ each represent a hydrogen atom, a halogen atom, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a sulfonyl group or an aryl group, at least one of which is a halogen atom. Y represents —C (═O) —, —SO— or —SO ₂ —.

The aryl group represented by Q ₂ may be monocyclic or condensed, and is preferably a monocyclic or bicyclic aryl group having 6 to 30 carbon atoms (for example, phenyl, naphthyl, etc.), more preferably Is a phenyl group or a naphthyl group, more preferably a phenyl group.

The heterocyclic group represented by Q ₂ is a 3- to 10-membered saturated or unsaturated heterocyclic group containing at least one atom of N, O or S, which may be monocyclic, Furthermore, you may form a condensed ring with another ring.

  The heterocyclic group is preferably a 5- to 6-membered unsaturated heterocyclic group which may have a condensed ring, and more preferably a 5- to 6-membered aromatic heterocyclic ring which may have a condensed ring. It is a group. More preferably, it is a 5- to 6-membered aromatic heterocyclic group optionally having a condensed ring containing a nitrogen atom, and particularly preferably 5 a condensed ring containing 1 to 4 nitrogen atoms. A 6-membered aromatic heterocyclic group. The heterocyclic ring in such a heterocyclic group is preferably imidazole, pyrazole, pyridine, pyrimidine, pyrazine, pyridazine, triazole, triazine, indole, indazole, purine, thiadiazole, oxadiazole, quinoline, phthalazine, naphthyridine, quinoxaline, quinazoline Cinnoline, pteridine, acridine, phenanthroline, phenazine, tetrazole, thiazole, oxazole, benzimidazole, benzoxazole, benzthiazole, indolenine, tetrazaindene, more preferably imidazole, pyridine, pyrimidine, pyrazine, pyridazine, triazole, Triazine, thiadiazole, oxadiazole, quinoline, phthalazine, naphthyridine, quinoxaline, quinoaline Zolin, cinnoline, tetrazole, thiazole, oxazole, benzimidazole, benzoxazole, benzthiazole, tetrazaindene, more preferably imidazole, pyridine, pyrimidine, pyrazine, pyridazine, triazole, triazine, thiadiazole, quinoline, phthalazine, naphthyridine, Quinoxaline, quinazoline, cinnoline, tetrazole, thiazole, benzimidazole, and benzthiazole are preferable, and pyridine, thiadiazole, quinoline, and benzthiazole are particularly preferable.

The aryl group and heterocyclic group represented by Q ₂ may have a substituent in addition to —Y—C (X ₁ ) (X ₂ ) (X ₃ ), and the substituent is preferably an alkyl group, Alkenyl group, aryl group, alkoxy group, aryloxy group, acyloxy group, acyl group, alkoxycarbonyl group, aryloxycarbonyl group, acyloxy group, acylamino group, alkoxycarbonylamino group, aryloxycarbonylamino group, sulfonylamino group, sulfamoyl Group, carbamoyl group, sulfonyl group, ureido group, phosphoric acid amide group, halogen atom, cyano group, sulfo group, carboxyl group, nitro group, heterocyclic group, more preferably alkyl group, aryl group, alkoxy group, aryl Oxy group, acyl group, acylamino group, alkoxycarbonylamino , Aryloxycarbonylamino group, sulfonylamino group, sulfamoyl group, carbamoyl group, ureido group, phosphoric acid amide group, halogen atom, cyano group, nitro group, heterocyclic group, more preferably alkyl group, aryl group, alkoxy group Group, aryloxy group, acyl group, acylamino group, sulfonylamino group, sulfamoyl group, carbamoyl group, halogen atom, cyano group, nitro group, heterocyclic group, particularly preferably alkyl group, aryl group, halogen atom .

X ₁ , X ₂ and X ₃ are preferably a halogen atom, haloalkyl group, acyl group, alkoxycarbonyl group, aryloxycarbonyl group, carbamoyl group, sulfamoyl group, sulfonyl group or heterocyclic group, more preferably a halogen atom , A haloalkyl group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group and a sulfonyl group, more preferably a halogen atom and a trihalomethyl group, and particularly preferably a halogen atom. Of the halogen atoms, preferred are a chlorine atom, a bromine atom and an iodine atom, more preferred are a chlorine atom and a bromine atom, and particularly preferred is a bromine atom.

Y represents —C (═O) —, —SO— or —SO ₂ —, preferably —SO ₂ —.

The amount of these compounds added can be 1 × 10 ⁻⁴ to 1 mol, preferably 1 × 10 ^{−3 to} 5 × 10 ⁻² mol, per mol of silver.

  In the imaging material of the present invention, the polyhalogen compound disclosed in JP-A-2003-5041 can also be used in the same manner as the compound represented by the above general formula (OFI).

  Specific examples of the compound represented by the general formula (OFI) are shown below, but the present invention is not limited thereto.

[Polymer image stabilizer]
In the photothermographic imaging material according to the present invention, it is possible to use, as an image stabilizer, a polymer having at least one repeating unit of a monomer having a halogen radical releasing group as disclosed in JP-A No. 2003-91054. In addition to being able to further stabilize the silver image, it is also preferable from the viewpoint of high sensitivity and high covering power. In particular, unexpectedly good results can be obtained in the silver salt photothermographic imaging material of the present invention.

[Silver ion reducing agent]
In the present invention, silver ion reducing agents (hereinafter also referred to simply as reducing agents) include U.S. Pat. Nos. 3,589,903, 4,021,249, and British Patent 1,486,148. Polyphenol compounds described in each specification and each publication of JP-A Nos. 51-51933, 50-36110, 50-116023, 52-84727, and JP-B 51-35727, for example, 2 , 2'-dihydroxy-1,1'-binaphthyl, 6,6'-dibromo-2,2'-dihydroxy-1,1'-binaphthyl and the like described in US Pat. No. 3,672,904 Bisnaphthols, for example, 4-benzenesulfonamidophenol, 2-benzenesulfonamidophenol, 2,6-dichloro-4-benzenesulfonamidophenol 4 benzenesulfonamide sulfonamidophenol or sulfonamide naphthols as described in U.S. Patent No. 3,801,321 of naphthol or the like can be used.

  However, in the present invention, the silver ion reducing agent is preferably a compound represented by the following general formula (RED).

In the above general formula (RED), X ₁ represents a chalcogen atom or CHR ₁ . The chalcogen atom is sulfur, selenium or tellurium, preferably a sulfur atom. CHR R ₁ in ₁ represents a hydrogen atom, a halogen atom, an alkyl group, an alkenyl group, an aryl group or a heterocyclic group, a halogen atom, a fluorine atom, a chlorine atom, a bromine atom, the alkyl group substituted or An unsubstituted alkyl group having 1 to 20 carbon atoms is preferred. Specific examples include methyl, ethyl, propyl, butyl, hexyl, heptyl, cycloalkyl, etc. Examples of the alkenyl group include vinyl, allyl, butenyl, hexenyl, hexadienyl, ethenyl-2-propenyl, 3-butenyl, 1-methyl- 3-propenyl, 3-pentenyl, 1-methyl-3-butenyl, cyclohexenyl, etc., aryl groups such as benzene ring, naphthalene ring, etc., heterocyclic groups such as thiophene, furan, imidazole, pyrazole, pyrrole, etc. is there. In particular, a cyclic group such as a cycloalkyl group and a cycloalkenyl group is preferable.

  These groups may further have a substituent. Specific examples of the substituent include a halogen atom (for example, fluorine, chlorine, bromine, etc.), an alkyl group (for example, methyl, ethyl, propyl, butyl, pentyl). , I-pentyl, 2-ethylhexyl, octyl, decyl etc.), cycloalkyl group (eg cyclohexyl, cycloheptyl etc.), alkenyl group (eg ethenyl-2-propenyl, 3-butenyl, 1-methyl-3-propenyl) , 3-pentenyl, 1-methyl-3-butenyl, etc.), cycloalkenyl groups (eg 1-cycloalkenyl, 2-cycloalkenyl groups etc.), alkynyl groups (eg ethynyl, 1-propynyl etc.), alkoxy groups ( For example, methoxy, ethoxy, propoxy, etc.), alkylcarbonyloxy group (for example, acetyloxy ), Alkylthio groups (eg, methylthio, trifluoromethylthio, etc.), carboxyl groups, alkylcarbonylamino groups (eg, acetylamino, etc.), ureido groups (eg, methylaminocarbonylamino, etc.), alkylsulfonylamino groups (eg, methane) Sulfonylamino etc.), alkylsulfonyl groups (eg methanesulfonyl, trifluoromethanesulfonyl etc.), carbamoyl groups (eg carbamoyl, N, N-dimethylcarbamoyl, N-morpholinocarbonyl etc.), sulfamoyl groups (eg sulfamoyl, N, N-dimethylsulfamoyl, morpholinosulfamoyl, etc.), trifluoromethyl group, hydroxyl group, nitro group, cyano group, alkylsulfonamide group (for example, methanesulfonamide, butans) Honamide etc.), alkylamino groups (eg amino, N, N-dimethylamino, N, N-diethylamino etc.), sulfo groups, phosphono groups, sulfite groups, sulfino groups, alkylsulfonylaminocarbonyl groups (eg methanesulfonyl) Aminocarbonyl, ethanesulfonylaminocarbonyl, etc.), alkylcarbonylaminosulfonyl groups (eg, acetamidosulfonyl, methoxyacetamidosulfonyl, etc.), alkynylaminocarbonyl groups (eg, acetamidocarbonyl, methoxyacetamidocarbonyl, etc.), alkylsulfinylaminocarbonyl groups (eg, Methanesulfinylaminocarbonyl, ethanesulfinylaminocarbonyl, etc.). Moreover, when there are two or more substituents, they may be the same or different. A particularly preferred substituent is an alkyl group.

R ₂ represents an alkyl group. The alkyl group is preferably a substituted or unsubstituted one having 1 to 20 carbon atoms, specifically, methyl, ethyl, propyl, i-propyl, butyl, i-butyl, t-butyl, t-pentyl, t-octyl. , Cyclohexyl, cyclopentyl, 1-methylcyclohexyl, 1-methylcyclopropyl and the like.

Although the substituent of the alkyl group is not particularly limited, for example, aryl group, hydroxyl group, alkoxy group, aryloxy group, alkylthio group, arylthio group, acylamino group, sulfonamido group, sulfonyl group, phosphoryl group, acyl group, carbamoyl Group, ester group, halogen atom and the like. Further, (R ₄ ) _n and (R ₄ ) _m may form a saturated ring. R ₂ is preferably a secondary or tertiary alkyl group, and preferably has 2 to 20 carbon atoms. A tertiary alkyl group is more preferred, t-butyl, t-pentyl and 1-methylcyclohexyl are more preferred, and t-butyl is most preferred.

R ₃ represents a hydrogen atom or a group that can be substituted on the benzene ring. Examples of groups that can be substituted on the benzene ring include halogen atoms such as fluorine, chlorine, bromine, alkyl groups, aryl groups, cycloalkyl groups, alkenyl groups, cycloalkenyl groups, alkynyl groups, amino groups, acyl groups, and acyloxy groups. , Acylamino group, sulfonylamino group, sulfamoyl group, carbamoyl group, alkylthio group, sulfonyl group, alkylsulfonyl group, sulfinyl group, cyano group, heterocyclic group and the like.

R ₃ is preferably methyl, ethyl, i-propyl, t-butyl, cyclohexyl, 1-methylcyclohexyl, 2-hydroxyethyl and the like. More preferred are methyl and 2-hydroxyethyl.

These groups may further have a substituent, and the substituents exemplified in the above R ₁ can be used as the substituent.

R ₃ is more preferably an alkyl group having 1 to 10 carbon atoms. In particular, a hydroxyl group described in Japanese Patent Application No. 2002-120842, or an alkyl group having a substituent capable of forming a hydroxyl group by being deprotected, such as a 2-hydroxyethyl group, can be mentioned. Such a reducing agent having an alkyl group may be used alone or in order to obtain a silver image density having a high maximum density (Dmax), that is, a high silver coverage (covering power), with a constant applied silver amount. It is preferable to use it together with a seed reducing agent.

The most preferred combination of R ₂ and R ₃ is that R ₂ is a tertiary alkyl group (eg, t-butyl, 1-methylcyclohexyl, etc.), R ₃ is an alkyl group, hydroxyl group, or deprotection Thus, an alkyl group having a group capable of forming a hydroxyl group as a substituent, for example, a 2-hydroxyethyl group. The plurality of R ₂ and R ₃ may be the same or different.

R ₄ represents a substitutable group on the benzene ring, specifically, an alkyl group having 1 to 25 carbon atoms (for example, methyl, ethyl, propyl, i-propyl, t-butyl, pentyl, hexyl, cyclohexyl, etc. ), Halogenated alkyl groups (eg, trifluoromethyl, perfluorooctyl, etc.), cycloalkyl groups (eg, cyclohexyl, cyclopentyl, etc.), alkynyl groups (eg, propargyl, etc.), glycidyl groups, acrylate groups, methacrylate groups, aryl Groups (eg, phenyl, etc.), heterocyclic groups (eg, pyridyl, thiazolyl, oxazolyl, imidazolyl, furyl, pyrrolyl, pyrazinyl, pyrimidinyl, pyridazinyl, selenazolyl, triphoranyl, piperidinyl, pyrazolyl, tetrazolyl, etc.), halogen atoms (eg, chlorine) , Silicon, iodine, fluorine), alkoxy groups (eg, methoxy, ethoxy, propyloxy, pentyloxy, cyclopentyloxy, hexyloxy, cyclohexyloxy, etc.), aryloxy groups (eg, phenoxy, etc.), alkoxycarbonyl groups (eg, methyl) Oxycarbonyl, ethyloxycarbonyl, butyloxycarbonyl etc.), aryloxycarbonyl group (eg phenyloxycarbonyl etc.), sulfonamide group (eg methanesulfonamide, ethanesulfonamide, butanesulfonamide, hexanesulfonamide group, cyclohexane Sulfonamides, benzenesulfonamides, etc.), sulfamoyl groups (for example, aminosulfonyl, methylaminosulfonyl, dimethylaminosulfonyl, butylaminosulfonyl, Hexylaminosulfonyl, cyclohexylaminosulfonyl, phenylaminosulfonyl, 2-pyridylaminosulfonyl, etc.), urethane groups (eg, methylureido, ethylureido, pentylureido, cyclohexylureido, phenylureido, 2-pyridylureido, etc.), acyl groups (eg, Acetyl, propionyl, butanoyl, hexanoyl, cyclohexanoyl, benzoyl, pyridinoyl, etc.), carbamoyl groups (eg, aminocarbonyl, methylaminocarbonyl, dimethylaminocarbonyl, propylaminocarbonyl, pentylaminocarbonyl group, cyclohexylaminocarbonyl, phenylamino) Carbonyl, 2-pyridylaminocarbonyl), amide group (eg, acetamide, propionamide, butane) Amide, hexaneamide, benzamide, etc.), sulfonyl groups (eg, methylsulfonyl, ethylsulfonyl, butylsulfonyl, cyclohexylsulfonyl, phenylsulfonyl, 2-pyridylsulfonyl, etc.), amino groups (eg, amino, ethylamino, dimethylamino, butyl) Amino, cyclopentylamino, anilino, 2-pyridylamino and the like), cyano group, nitro group, sulfo group, carboxyl group, hydroxyl group, oxamoyl group and the like. These groups may be further substituted with these groups. n and m represent an integer of 0 to 2, and most preferably n and m are 0. A plurality of R ₄ may be the same or different.

R ₄ may form a saturated ring with R ₂ and R ₃ . R ₄ is preferably a hydrogen atom, a halogen atom or an alkyl group, more preferably a hydrogen atom.

  Specific examples of the compound represented by the general formula (RED) are given below, but the present invention is not limited thereto.

  These compounds (bisphenol compounds) represented by the general formula (RED) can be easily synthesized by a conventionally known method (for example, see Reference: Japanese Patent Application No. 2002-147562).

  The amount of the silver ion reducing agent used in the photothermographic dry imaging material of the present invention varies depending on the type of organic silver salt, the reducing agent, and other additives. A suitable amount is from 05 mol to 10 mol, preferably from 0.1 mol to 3 mol. Within this range, two or more silver ion reducing agents of the present invention may be used in combination. That is, it is preferable from the viewpoints of obtaining a high-quality and high-CP image that the use of reducing agents having different reactivity due to having different chemical structures is excellent in storage stability.

  In the present invention, the method in which the reducing agent is added to and mixed with a photosensitive emulsion solution composed of photosensitive silver halide and organic silver salt grains and a solvent immediately before coating is preferable because the photographic performance fluctuation due to the stagnation time is small. is there.

  In the imaging material of the present invention, as development accelerators used in combination with the reducing agent, the general formulas (1) to (4) described in JP-A No. 2003-43614 and JP-A No. 2003-66559 are described. Hydrazine derivatives and phenol derivatives represented by the general formulas (1) to (3) are preferably used.

  The oxidation potential by polarographic measurement of the development accelerator used in the imaging material of the present invention is preferably 0.01 V to 0.4 V lower than the compound represented by the general formula (RED). More preferably, it is 0.01 V to 0.3 V lower than the compound represented by (RED). The development accelerator had an oxidation potential of 0.2 V or more by polarography measurement at the SCE counter electrode in a tetrahydrofuran: Britton / Robinson buffer solution adjusted to pH 6.0 = 3: 2 mixed solvent. .6V or less is preferable, and 0.3V or more and 0.55V or less is more preferable. The pKa value in a 3: 2 mixed solvent of tetrahydrofuran: water is preferably 3 or more and 12 or less, more preferably 5 or more and 10 or less. Tetrahydrofuran with pH adjusted to 6.0: Britton-Robinson buffer solution = 3: 2 In a mixed solvent, the oxidation potential by polarography measurement at the SCE counter electrode is 0.3 V or more and 0.55 V or less. : The pKa value in a 3: 2 mixed solvent of water is particularly preferably 5 or more and 10 or less.

  As the silver ion reducing agent according to the present invention, various reducing agents disclosed in European Patent No. 1,278,101 and Japanese Patent Application Laid-Open No. 2003-15252 can also be used.

  The amount of the silver ion reducing agent used in the silver salt photothermographic dry imaging material of the present invention varies depending on the type of organic silver salt, reducing agent, and other additives, but in general, per mole of organic silver salt. 0.05 mol to 10 mol, preferably 0.1 mol to 3 mol is appropriate. Within this range, two or more silver ion reducing agents according to the present invention may be used in combination. That is, it is preferable from the viewpoints of obtaining a high-quality and high-CP image that the use of reducing agents having different reactivity due to having different chemical structures is excellent in storage stability.

[Inhibitors of thiosulfonic acids]
The imaging material of the present invention preferably contains a compound represented by the following general formula (ST).

General formula (ST)
Z-SO ₂ / SM
In the above general formula (ST), Z represents a substituted or unsubstituted alkyl group, aryl group, heterocyclic group or aromatic ring group, and M represents a metal atom or an organic cation.

  The alkyl group, aryl group, heterocyclic group, aromatic ring and heterocyclic ring represented by Z may be substituted. Examples of the substituent include a lower alkyl group such as a methyl group and an ethyl group, an aryl group such as a phenyl group, an alkoxyl group having 1 to 8 carbon atoms, a halogen atom such as chlorine, a nitro group, an amino group, and a carboxyl group. Can be mentioned. Examples of the heterocycle represented by Z include thiazole, benzthiazole, imidazole, benzimidazole, and oxazole ring. The metal atom represented by M is preferably an alkali metal atom such as sodium ion or potassium ion, and the organic cation is preferably an ammonium ion or a guanidine group.

[Vinyl type inhibitor having electron withdrawing group]
In the present invention, it is preferable to use a fog inhibitor represented by the following general formula (CV) described in Japanese Patent Application No. 2003-199555.

In the general formula (CV), X represents an electron withdrawing group, and W represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a heterocyclic group, a halogen atom, a cyano group, an acyl group, a thioacyl group, or an oxalyl group. Group, oxyoxalyl group, -S-oxalyl group, oxamoyl group, oxycarbonyl group, -S-carbonyl group, carbamoyl group, thiocarbamoyl group, sulfonyl group, sulfinyl group, oxysulfonyl group, -S-sulfonyl group, sulfamoyl group Oxysulfinyl group, -S-sulfinyl group, sulfinamoyl group, phosphoryl group, nitro group, imino group, N-carbonylimino group, N-sulfonylimino group, ammonium group, sulfonium group, phosphonium group, pyrylium group, or immonium represents a group, R ₁ is a hydroxyl group Other represents the salt of hydroxyl group, R ₂ represents an alkyl group, an alkenyl group, an alkynyl group, an aryl group or a heterocyclic group. X and W may combine with each other to form a cyclic structure. X and R ₁ are shown in cis form, but X and R ₁ include transformer form.

  The electron withdrawing group represented by X is a substituent whose Hammett's substituent constant σp can take a positive value. Specifically, a substituted alkyl group (such as halogen-substituted alkyl), a substituted alkenyl group (such as cyanovinyl), a substituted or unsubstituted alkynyl group (such as trifluoromethylacetylenyl, cyanoacetylenyl, formylacetylenyl), Substituted aryl groups (such as cyanophenyl), substituted and unsubstituted heterocyclic groups (such as pyridyl, triazinyl, benzoxazolyl), halogen atoms, cyano groups, acyl groups (such as acetyl and trifluoroacetyl), thioacyl groups (such as thioformyl) , Thioacetyl etc.), oxalyl group (methyl oxalyl etc.), oxyoxalyl group (ethoxalyl etc.), -S-oxalyl group (ethyl thiooxalyl etc.), oxamoyl group (methyl oxamoyl etc.), oxycarbonyl group (ethoxycarbonyl, carboxyl) Etc.), -S-carbonyl group (ethyl) Ocarbonyl), carbamoyl group, thiocarbamoyl group, sulfonyl group, sulfinyl group, oxysulfonyl group (ethoxysulfonyl etc.), -S-sulfonyl group (ethylthiosulfonyl etc.), sulfamoyl group, oxysulfinyl group (methoxysulfinyl etc.) , -S-sulfinyl group (such as methylthiosulfinyl group), sulfinamoyl group, phosphoryl group, nitro group, imino group (imino, N-methylimino, N-phenylimino, N-pyridylimino, N-cyanoimino, N-nitroimino, etc.), N -Carbonylimino group (N-acetylimino, N-ethoxycarbonylimino, N-ethoxalylimino, N-formylimino, N-trifluoroacetylimino, N-carbamoylimino, etc.), N-sulfonylimino group (N-methanes) Phonylimino, N-trifluoromethanesulfonylimino, N-methoxysulfonylimino, N-sulfamoylimino, etc.), ammonium group, sulfonium group, phosphonium group, pyrylium group, immonium group, etc., ammonium group, sulfonium group In addition, a heterocyclic group in which a phosphonium group, an immonium group or the like forms a ring is also included. However, X excludes a formyl group. The σp value is preferably 0.2 or more, and more preferably 0.3 or more.

  W includes a hydrogen atom, an alkyl group (methyl, ethyl, trifluoromethyl, etc.), an alkenyl group (vinyl, halogen-substituted vinyl, cyanovinyl, etc.), an alkynyl group (acetylenyl, cyanoacetylenyl, etc.), an aryl group (phenyl, chlorophenyl). , Nitrophenyl, cyanophenyl, pentafluorophenyl, etc.), heterocyclic groups (pyridyl, pyrimidyl, pyrazinyl, quinoxalinyl, triazinyl, succinimide, tetrazolyl, triazolyl, imidazolyl, benzoxazolyl, etc.) Halogen atom, cyano group, acyl group, thioacyl group, oxalyl group, oxyoxalyl group, -S-oxalyl group, oxamoyl group, oxycarbonyl group, -S-carbonyl group, carbamoyl group, thiocarbamoyl group, sulfonyl , Sulfinyl group, oxysulfonyl group, -S-sulfonyl group, sulfamoyl group, oxysulfinyl group, -S-sulfinyl group, sulfinamoyl group, phosphoryl group, nitro group, imino group, N-carbonylimino group, N-sulfonylimino group , Ammonium group, sulfonium group, phosphonium group, pyrylium group, immonium group and the like. However, the formyl group is excluded as W.

  W is preferably an electron withdrawing group other than a formyl group in which Hammett's substituent constant σp can take a positive value, as well as an aryl group and a heterocyclic group as described above.

  X and W may be bonded to each other to form a cyclic structure. Examples of the ring formed by X and W include a saturated or unsaturated carbocycle or heterocycle which may have a condensed ring, and may be a cyclic ketone. As the heterocyclic ring, those containing at least one atom, more preferably 1-2, of N, O and S are preferable.

R ₁ includes a hydroxyl group or an organic or inorganic salt of a hydroxyl group. Specific examples of the alkyl group, alkenyl group, alkynyl group, aryl group and heterocyclic group represented by R ₂ include the examples of the alkyl group, alkenyl group, alkynyl group, aryl group and heterocyclic group exemplified as W. It is done.

In the present invention, X, W and R ₂ may all contain a diffusion-resistant group. The anti-diffusion group is called a ballast group in a photographic coupler or the like, and has a bulky molecular weight such that the added compound does not move in the film of the photosensitive material.

In the present invention, X, W and R ₂ may contain an adsorption promoting group for silver salt. Adsorption promoting groups for silver salts include thioamide groups, aliphatic mercapto groups, aromatic mercapto groups, heterocyclic mercapto groups and benzotriazoles, triazoles, tetrazoles, indazoles, benzimidazoles, imidazoles, benzothiazoles, thiazoles, benzoxazoles, Examples include groups represented by 5- to 6-membered nitrogen-containing heterocycles such as oxazole, thiadiazole, oxadiazole, and triazine.

  In the present invention, it is preferable that at least one of X and W represents a cyano group, or X and W are bonded to each other to form a cyclic structure.

In the present invention, a compound containing a thioether group (—S—) in the substituents represented by X, W and R ₂ is preferred.

  Further, among X and W, those having at least one alkene group represented by the following general formula (CV1) are particularly preferred.

General formula (CV1)
-C (R) = C (Y) (Z)
In the above formula, R represents a hydrogen atom or a substituent, and Y and Z each represent a hydrogen atom or a substituent, and at least one of Y and Z represents an electron-withdrawing group.

  Examples of the electron-withdrawing group among the substituents represented by Y and Z include those mentioned above as the electron-withdrawing group for X and W, the formyl group, and the like.

  Examples of X and W represented by the general formula (CV1) include the following groups.

  Further, it is also preferable that at least one of X and W has the following alkyne group.

R ₅ represents a hydrogen atom or a substituent, and the substituent is preferably an electron-withdrawing group as exemplified in X and W described above. Examples of X and W represented by the general formula (CV1) include the following groups.

  In addition, among X and W, those having at least one acyl group selected from a substituted alkylcarbonyl group, an alkenylcarbonyl group, and an alkynylcarbonyl group are also preferred. Examples of X and W include the following groups.

  Moreover, what has at least one oxalyl group among X and W is also preferable, and the following groups are mentioned as X and W which have an oxalyl group, for example.

_{And, -COCOCH 3, -COCOOC 2 H 5} , -COCONHCH 3, -COCOSC 2 H 5, -COCOOC 2 H 4 SCH 3, -COCONHC 2 H 4 SCH 3.

  In addition, it is preferable that at least one of X and W has an aryl group substituted with an electron-withdrawing group or a nitrogen-containing heterocyclic group. Examples of such X and W include the following groups.

In the present invention, the alkene compound represented by the general formula (CV) includes all isomers when it can take an isomer structure with respect to the double bond substituted by X, W, R ₁ and R ₂ . In addition, all isomers are included when a tautomeric structure such as keto-enol can be taken.

The compound represented by the general formula (CV) may be contained in at least one of the photosensitive layer of the photothermographic material or the non-photosensitive layer on the photosensitive layer side, but preferably in at least the photosensitive layer. It is to contain. The amount of the compound represented by the general formula (1) is preferably 1 × 10 ⁻⁸ to 1 mol, more preferably 1 × 10 ⁻⁶ to 1 × 10 ⁻¹ mol, relative to 1 mol of silver, 1 ×. 10 ⁻⁴ to 1 × 10 ⁻² mol is most preferred.

  The compound represented by the general formula (CV) can be added to the photosensitive layer and the non-photosensitive layer according to a known method. That is, it can be dissolved in alcohols such as methanol and ethanol, ketones such as methyl ethyl ketone and acetone, polar solvents such as dimethyl sulfoxide and dimethylformamide, and added to the coating solution for the photosensitive layer and the non-photosensitive layer. . Further, fine particles of 1 μm or less can be dispersed and added in water or an organic solvent. Many techniques for fine particle dispersion are disclosed, but they can be dispersed according to these techniques.

[Silver saving agent]
In the imaging material of the present invention, the photosensitive layer or the non-photosensitive layer can contain a silver saving agent.

  The silver saving agent used in the present invention refers to a compound that can reduce the amount of silver necessary to obtain a certain silver image density. Various action mechanisms of the function of decreasing can be considered, but a compound having a function of improving the covering power (covering power) of developed silver is preferable. Here, the covering power of developed silver refers to the optical density per unit amount of silver. This silver saving agent can be present in the photosensitive layer, the non-photosensitive layer, or both.

  Preferred examples of the silver saving agent include hydrazine derivatives represented by the following general formula (H), vinyl compounds represented by the following general formula (G), quaternary onium compounds represented by the following general formula (P), and the like. As mentioned.

In the general formula (H), A ₀ represents an aliphatic group, an aromatic group, a heterocyclic group, or a —G ₀ -D ₀ group that may have a substituent, and B ₀ represents a blocking group. ₁ and A ₂ both represent a hydrogen atom, or one represents a hydrogen atom and the other represents an acyl group, a sulfonyl group or an oxalyl group. Here, G ₀ is —CO— group, —COCO— group, —CS— group, —C (═NG ₁ D ₁ ) — group, —SO— group, —SO ₂ — group or —P (O) ( G ₁ D ₁ ) — group, G ₁ represents a simple bond, —O— group, —S— group or —N (D ₁ ) — group, D ₁ represents an aliphatic group, aromatic group, complex When a ring group or a hydrogen atom is represented and a plurality of D ₁ are present in the molecule, they may be the same or different. D ₀ represents a hydrogen atom, an aliphatic group, an aromatic group, a heterocyclic group, an amino group, an alkoxy group, an aryloxy group, an alkylthio group, or an arylthio group. Preferred D ₀ includes a hydrogen atom, an alkyl group, an alkoxy group, an amino group and the like.

In the general formula (H), the aliphatic group represented by A ₀ is preferably one having 1 to 30 carbon atoms, particularly preferably a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms. Examples thereof include a methyl group, an ethyl group, a t-butyl group, an octyl group, a cyclohexyl group, and a benzyl group. These are further suitable substituents (for example, an aryl group, an alkoxy group, an aryloxy group, an alkylthio group, an arylthio group, a sulfoxy group). Group, sulfonamido group, sulfamoyl group, acylamino group, ureido group, etc.).

In the general formula (H), the aromatic group represented by A ₀ is preferably a monocyclic or condensed aryl group, and examples thereof include a benzene ring or a naphthalene ring, and examples of the heterocyclic group represented by A ₀ include A heterocyclic ring containing at least one heteroatom selected from nitrogen, sulfur and oxygen atoms in a single ring or a condensed ring is preferred, such as a pyrrolidine ring, an imidazole ring, a tetrahydrofuran ring, a morpholine ring, a pyridine ring, a pyrimidine ring, a quinoline ring, Examples include a thiazole ring, a benzothiazole ring, a thiophene ring, and a furan ring. Aromatic groups A _0, heterocyclic group or -G ₀ -D ₀ group may have a substituent. Particularly preferred as A ₀ are an aryl group and a —G ₀ -D ₀ group.

In the general formula (H), A ₀ preferably contains at least one anti-diffusion group or silver halide adsorption group. As the anti-diffusion group, a ballast group commonly used in an immobile photographic additive such as a coupler is preferable. As the ballast group, an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, phenyl, which are photographically inactive, are preferable. Group, phenoxy group, alkylphenoxy group and the like, and the total number of carbon atoms in the substituent portion is preferably 8 or more.

  In the general formula (H), examples of the silver halide adsorption promoting group include thiourea, thiourethane group, mercapto group, thioether group, thione group, heterocyclic group, thioamide heterocyclic group, mercapto heterocyclic group, and JP-A-64. And the adsorbing group described in -90439.

In the general formula (H), B ₀ represents a blocking group, preferably a -G ₀ -D ₀ group, and G ₀ is a -CO- group, a -COCO- group, a -CS- group, -C (= NG ₁ D ₁ ) — group, —SO— group, —SO ₂ — group or —P (O) (G ₁ D ₁ ) — group. Preferred examples of G ₀ include —CO— group and —COCO— group, G ₁ represents a simple bond, —O— group, —S— group or —N (D ₁ ) — group, and D ₁ represents fatty acid. Represents a group, an aromatic group, a heterocyclic group or a hydrogen atom, and when a plurality of D ₁ are present in the molecule, they may be the same or different. D ₀ represents a hydrogen atom, an aliphatic group, an aromatic group, a heterocyclic group, an amino group, an alkoxy group, an aryloxy group, an alkylthio group, or an arylthio group, and preferred D ₀ is a hydrogen atom, an alkyl group, an alkoxy group, An amino group etc. are mentioned. A ₁ and A ₂ are both hydrogen atoms, or one is a hydrogen atom and the other is an acyl group (acetyl group, trifluoroacetyl group, benzoyl group, etc.), sulfonyl group (methanesulfonyl group, toluenesulfonyl group, etc.), or oxalyl group (Etoxalyl group, etc.).

  These compounds represented by the general formula (H) can be easily synthesized by known methods. For example, it can be synthesized with reference to US Pat. Nos. 5,464,738 and 5,496,695.

  Other hydrazine derivatives that can be preferably used include compounds H-1 to H-29 described in U.S. Pat. No. 5,545,505 columns 11 to 20, and U.S. Pat. No. 5,464,738 columns 9 to 11. Compounds 1 to 12 described. These hydrazine derivatives can be synthesized by a known method.

  In the general formula (G), X and R are represented in the form of cis, but the form in which X and R are trans is also included in the general formula (G). The same applies to the structure display of a specific compound.

  In General Formula (G), X represents an electron-withdrawing group, and W represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a heterocyclic group, a halogen atom, an acyl group, a thioacyl group, an oxalyl group, an oxy group. Oxalyl, thiooxalyl, oxamoyl, oxycarbonyl, thiocarbonyl, carbamoyl, thiocarbamoyl, sulfonyl, sulfinyl, oxysulfinyl, thiosulfinyl, sulfamoyl, oxysulfinyl, thiosulfinyl, Sulfinamoyl group, phosphoryl group, nitro group, imino group, N-carbonylimino group, N-sulfonylimino group, dicyanoethylene group, ammonium group, sulfonium group, phosphonium group, pyrylium group, immonium group are represented.

  R is a halogen atom, hydroxyl group, alkoxy group, aryloxy group, heterocyclic oxy group, alkenyloxy group, acyloxy group, alkoxycarbonyloxy group, aminocarbonyloxy group, mercapto group, alkylthio group, arylthio group, heterocyclic thio group , An alkenylthio group, an acylthio group, an alkoxycarbonylthio group, an aminocarbonylthio group, an organic or inorganic salt of a hydroxyl group or a mercapto group (for example, sodium salt, potassium salt, silver salt, etc.), amino group, alkylamino group, Cyclic amino group (for example, pyrrolidino group), acylamino group, oxycarbonylamino group, heterocyclic group (5-6 membered nitrogen-containing heterocycle such as benztriazolyl group, imidazolyl group, triazolyl group, tetrazolyl group, etc.), Ureido group, sulfone It represents a bromide group. X and W, X and R may be bonded to each other to form a cyclic structure. Examples of the ring formed by X and W include pyrazolone, pyrazolidinone, cyclopentanedione, β-ketolactone, β-ketolactam and the like.

  The general formula (G) will be further described. The electron-withdrawing group represented by X is a substituent whose substituent constant σp can take a positive value. Specifically, a substituted alkyl group (such as halogen-substituted alkyl), a substituted alkenyl group (such as cyanovinyl), a substituted / unsubstituted alkynyl group (such as trifluoromethylacetylenyl, cyanoacetylenyl), a substituted aryl group (such as cyano) Phenyl, etc.), substituted / unsubstituted heterocyclic groups (pyridyl, triazinyl, benzoxazolyl, etc.), halogen atoms, cyano groups, acyl groups (acetyl, trifluoroacetyl, formyl, etc.), thioacetyl groups (thioacetyl, thioformyl, etc.) ), Oxalyl group (such as methyloxalyl), oxyoxalyl group (such as etoxalyl), thiooxalyl group (such as ethylthiooxalyl), oxamoyl group (such as methyloxamoyl), oxycarbonyl group (such as ethoxycarbonyl), carboxyl group, thiol Carbonyl group (ethylthiocarboni ), Carbamoyl group, thiocarbamoyl group, sulfonyl group, sulfinyl group, oxysulfonyl group (ethoxysulfonyl etc.), thiosulfonyl group (ethylthiosulfonyl etc.), sulfamoyl group, oxysulfinyl group (methoxysulfinyl etc.), thiosulfinyl group (Such as methylthiosulfinyl), sulfinamoyl group, phosphoryl group, nitro group, imino group, N-carbonylimino group (N-acetylimino etc.), N-sulfonylimino group (N-methanesulfonylimino etc.), dicyanoethylene group, ammonium Group, sulfonium group, phosphonium group, pyrylium group, immonium group, and the like include a heterocyclic group in which an ammonium group, sulfonium group, phosphonium group, immonium group and the like form a ring. A substituent having a σp value of 0.30 or more is particularly preferable.

  Examples of the alkyl group represented by W include methyl, ethyl, trifluoromethyl, etc., examples of the alkenyl group include vinyl, halogen-substituted vinyl, cyanovinyl, etc., examples of the alkynyl group include acetylenyl, cyanoacetylenyl, and the like as the aryl group. Nitrophenyl, cyanophenyl, pentafluorophenyl and the like, and examples of the heterocyclic group include pyridyl, pyrimidyl, triazinyl, succinimide, tetrazolyl, triazolyl, imidazolyl and benzoxazolyl. W is preferably an electron-withdrawing group having a positive σp value, and more preferably 0.30 or more.

  Among the substituents of R, a hydroxyl group, a mercapto group, an alkoxy group, an alkylthio group, a halogen atom, an organic or inorganic salt of a hydroxyl group or a mercapto group, and a heterocyclic group are preferable, and a hydroxyl group, more preferably An organic or inorganic salt of an alkoxy group, a hydroxyl group or a mercapto group, or a heterocyclic group is exemplified, and an organic or inorganic salt of a hydroxyl group, a hydroxyl group or a mercapto group is particularly preferred.

  Of the substituents X and W, those having a thioether bond in the substituent are preferred.

In the general formula (P), Q ₃ represents a nitrogen atom or a phosphorus atom, R ₁ , R ₂ , R ₃ and R ₄ each represent a hydrogen atom or a substituent, and X ⁻ represents an anion. R _{1 to} R ₄ may be connected to each other to form a ring.

Examples of the substituent represented by R _{1 to} R ₄ include an alkyl group (for example, a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group, a cyclohexyl group), an alkenyl group (for example, an allyl group, a butenyl group). Group), alkynyl group (eg, propargyl group, butynyl group, etc.), aryl group (eg, phenyl group, naphthyl group, etc.), heterocyclic group (eg, piperidinyl group, piperazinyl group, morpholinyl group, pyridyl group, furyl group) , Thienyl group, tetrahydrofuryl group, tetrahydrothienyl group, sulfolanyl group, etc.), amino group and the like.

Examples of the ring that R _{1 to} R ₄ can be formed by connecting to each other include a piperidine ring, a morpholine ring, a piperazine ring, a quinuclidine ring, a pyridine ring, a pyrrole ring, an imidazole ring, a triazole ring, and a tetrazole ring.

The group represented by R _{1 to} R ₄ may have a substituent such as a hydroxyl group, an alkoxy group, an aryloxy group, a carboxyl group, a sulfo group, an alkyl group, and an aryl group. R ₁ , R ₂ , R ₃ and R ₄ are preferably a hydrogen atom and an alkyl group.

Examples of the anion represented by X ⁻ include inorganic and organic anions such as halogen ions, sulfate ions, nitrate ions, acetate ions, and p-toluenesulfonate ions.

The quaternary onium compound can be easily synthesized in accordance with a known method. For example, the tetrazolium compound can be synthesized by referring to Chemical Reviews vol. 55 p. The method described in 335-483 can be referred to. The amount of the silver saving agent added is in the range of 1 × 10 ⁻⁵ to 1 mol, preferably 1 × 10 ^{−4 to} 5 × 10 ⁻¹ mol, per mol of the aliphatic carboxylic acid silver salt.

  In the present invention, it is also preferred that at least one silver saving agent is a silane compound. In the present invention, the silane compound used as a silver saving agent is preferably an alkoxysilane compound having two or more primary or secondary amino groups as disclosed in JP-A No. 2003-5324 or a salt thereof. .

  As a silver saving agent, when an alkoxysilane compound or a salt thereof, or a Schiff base is added to the image forming layer, it is preferably added in a range of usually 0.00001 to 0.05 mol with respect to 1 mol of silver. . The same category applies when both an alkoxysilane compound or a salt thereof and a Schiff base are added to the image forming layer.

〔binder〕
Binders suitable for the silver salt photothermographic dry imaging materials of the present invention are transparent or translucent and generally colorless and are natural polymer synthetic resins, polymers and copolymers, and other media forming films such as: gelatin, gum arabic, Poly (vinyl alcohol), hydroxyethyl cellulose, cellulose acetate, cellulose acetate butyrate, poly (vinyl pyrrolidone), casein, starch, poly (acrylic acid), poly (methyl methacrylic acid), poly (vinyl chloride), poly (methacrylic acid) ), Copoly (styrene-maleic anhydride), copoly (styrene-acrylonitrile), copoly (styrene-butadiene), poly (vinyl acetal) s (eg, poly (vinyl formal) and poly (vinyl butyral)), poly (esters) Polyesters, polyurethanes, phenoxy resins, poly (vinylidene chloride), poly (epoxides), poly (carbonates), poly (vinyl acetate), cellulose esters, and polyamides. It may be hydrophilic or non-hydrophilic.

  Preferred binders for the photosensitive layer of the silver salt photothermographic dry imaging material of the present invention are polyvinyl acetals, and a particularly preferred binder is polyvinyl butyral. Details will be described later. In addition, for non-photosensitive layers such as overcoat layers and undercoat layers, especially protective layers and backcoat layers, cellulose esters which are polymers having a higher softening temperature, particularly polymers such as triacetyl cellulose and cellulose acetate butyrate Is preferred. In addition, as needed, said binder can be used in combination of 2 or more type.

Such a binder is used in an effective range to function as a binder. The effective range can be easily determined by one skilled in the art. For example, as an index for holding at least an aliphatic carboxylic acid silver salt in the photosensitive layer, the ratio of the binder to the aliphatic carboxylic acid silver salt is 15: 1 to 1: 2, particularly 8: 1 to 1: 1. The range of is preferable. That is, it is preferable amount of the binder in the photosensitive layer is 1.5~6g / m ^2. More preferably, it is 1.7-5 g / m < ² >. If it is less than 1.5 g / m ² , the density of the unexposed area is significantly increased and may not be used.

  In the present invention, the heat transition temperature after development at a temperature of 100 ° C. or higher is preferably 46 ° C. or higher and 200 ° C. or lower, more preferably 70 ° C. or higher and 105 ° C. or lower. The heat transition temperature referred to in the present invention is a value indicated by the VICAT softening point or ring-and-ball method, and is a differential scanning calorimeter (DSC), for example, EXSTAR 6000 (manufactured by Seiko Electronics), DSC220C (manufactured by Seiko Electronics Industry). DSC-7 (manufactured by Perkin Elmer) or the like is used to indicate the endothermic peak when the thermally developed photosensitive layer is isolated and measured. Generally, a polymer compound has a glass transition point Tg, but in a silver salt photothermographic dry imaging material, a large endothermic peak is present at a position lower than the Tg value of the binder resin used in the photosensitive layer. Appear. As a result of diligent investigation focusing on this thermal transition point temperature, by setting the thermal transition point temperature to 46 ° C. or higher and 200 ° C. or lower, not only the fastness of the formed coating film is increased, but also the sensitivity, maximum It is preferable from the viewpoint of greatly improving photographic performance such as density and image storage stability.

  The glass transition temperature (Tg) was obtained by the method described in “Polymer Handbook” pages III-139 to III-179 (1966, Wiley and Sun, Inc.) by Brandrup et al. Tg in the case of a polymer resin is obtained by the following formula.

Tg (copolymer) (° C.) = V ₁ Tg ₁ + v ₂ Tg ₂ +... + V _n Tg _{n
Wherein, v 1, v 2 ··· v} n represents the mass fraction of the monomer in the _{copolymer, Tg 1, Tg 2 ··· Tg} n are each monomer in the copolymer Tg (° C.) of a single polymer obtained from the body. ]
The accuracy of Tg calculated according to the above equation is ± 5 ° C.

  In the silver salt photothermographic dry imaging material of the present invention, as the binder contained in the photosensitive layer containing aliphatic carboxylic acid silver salt, photosensitive silver halide grains, reducing agent, etc. on the support, specifically, Conventionally known polymer compounds can be used, such as vinyl chloride, vinyl acetate, vinyl alcohol, maleic acid, acrylic acid, acrylic acid ester, vinylidene chloride, acrylonitrile, methacrylic acid, methacrylic acid ester, styrene, butadiene, There are compounds made of polymers or copolymers containing ethylenically unsaturated monomers such as ethylene, vinyl butyral, vinyl acetal and vinyl ether as constituent units, polyurethane resins, and various rubber resins.

  Moreover, phenol resin, epoxy resin, polyurethane curable resin, urea resin, melamine resin, alkyd resin, formaldehyde resin, silicone resin, epoxy-polyamide resin, polyester resin, and the like can be given. These resins are described in detail in “Plastic Handbook” issued by Asakura Shoten.

  Polymers or copolymers containing such ethylenically unsaturated monomers as structural units include acrylic acid alkyl esters, acrylic acid aryl esters, methacrylic acid alkyl esters, methacrylic acid aryl esters, alkyl cyanoacrylates. Ester, cyanoacrylic acid aryl ester and the like, and the alkyl group and aryl group thereof may or may not be substituted. Specifically, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, amyl, hexyl, cyclohexyl, benzyl, chlorobenzyl, octyl, stearyl, sulfopropyl, N-ethyl-phenylaminoethyl, 2- (3-phenylpropyloxy) ethyl , Dimethyl Minophenoxyethyl, furfuryl, tetrahydrofurfuryl, phenyl, cresyl, naphthyl, 2-hydroxyethyl, 4-hydroxybutyl, triethylene glycol, dipropylene glycol, 2-methoxyethyl, 3-methoxybutyl, 2-acetoxyethyl, 2 -Acetoacetoxyethyl, 2-ethoxyethyl, 2-iso-propoxyethyl, 2-butoxyethyl, 2- (2-methoxyethoxy) ethyl, 2- (2-ethoxyethoxy) ethyl, 2- (2-butoxyethoxy) Examples thereof include ethyl, 2-diphenylphosphorylethyl, ω-methoxypolyethylene glycol (addition mole number n = 6), allyl, dimethylaminoethylmethyl chloride salt and the like.

  In addition, the following monomers can be used. Specific examples of vinyl esters include vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl caproate, vinyl chloroacetate, vinyl methoxyacetate, vinyl phenyl acetate, vinyl benzoate, vinyl salicylate. N-substituted acrylamides, N-substituted methacrylamides and acrylamides, methacrylamides: N-substituents include methyl, ethyl, propyl, butyl, tert-butyl, cyclohexyl, benzyl, hydroxymethyl, methoxyethyl, dimethyl Aminoethyl, phenyl, dimethyl, diethyl, β-cyanoethyl, N- (2-acetoacetoxyethyl), diacetone and the like; olefins: for example, dicyclopentadiene, ethylene, propylene, 1- Ten, 1-pentene, vinyl chloride, vinylidene chloride, isoprene, chloroprene, butadiene, 2,3-dimethylbutadiene, etc .; styrenes: for example, methylstyrene, dimethylstyrene, trimethylstyrene, ethylstyrene, isopropylstyrene, tert-butylstyrene , Chloromethyl styrene, methoxy styrene, acetoxy styrene, chloro styrene, dichloro styrene, bromo styrene, vinyl benzoic acid methyl ester, etc .; vinyl ethers: for example, methyl vinyl ether, butyl vinyl ether, hexyl vinyl ether, methoxyethyl vinyl ether, dimethylaminoethyl vinyl ether N-substituted maleimides: As N-substituent, methyl, ethyl, propyl, butyl, tert-butyl, cyclohexyl , Benzyl, n-dodecyl, phenyl, 2-methylphenyl, 2,6-diethylphenyl, 2-chlorophenyl, etc .; others include butyl crotonate, hexyl crotonate, dimethyl itaconate, dibutyl itaconate , Diethyl maleate, dimethyl maleate, dibutyl maleate, diethyl fumarate, dimethyl fumarate, dibutyl fumarate, methyl vinyl ketone, phenyl vinyl ketone, methoxyethyl vinyl ketone, glycidyl acrylate, glycidyl methacrylate, N-vinyl oxazolidone, N -Vinylpyrrolidone, acrylonitrile, methacrylonitrile, methylenemalonnitrile, vinylidene chloride and the like can be mentioned.

  Among these, particularly preferred examples include methacrylic acid alkyl esters, methacrylic acid aryl esters, styrenes, and the like. Among such polymer compounds, it is preferable to use a polymer compound having an acetal group. The polymer compound having an acetal group is preferable because it is excellent in compatibility with the aliphatic carboxylic acid to be produced and has a great effect of preventing the film from being softened.

  As the polymer compound having an acetal group, a compound represented by the following general formula (V) is particularly preferable.

In the general formula (V), R ₁ represents an alkyl group, a substituted alkyl group, an aryl group or a substituted aryl group, but is preferably a group other than an aryl group. R ₂ represents an unsubstituted alkyl group, a substituted alkyl group, an unsubstituted aryl group, a substituted aryl group, —COR ₃ or —CONHR ₃ . R ₃ has the same meaning as R ₁ .

The unsubstituted alkyl group represented by R ₁ , R ₂ , or R ₃ is preferably an alkyl group having 1 to 20 carbon atoms, particularly preferably 1 to 6 carbon atoms. These may be linear or branched, and preferably a linear alkyl group. Examples of such unsubstituted alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, n-amyl, t-amyl, n -Hexyl group, cyclohexyl group, n-heptyl group, n-octyl group, t-octyl group, 2-ethylhexyl group, n-nonyl group, n-decyl group, n-dodecyl group, n-octadecyl group, etc. Is particularly preferably a methyl group or a propyl group.

  As an unsubstituted aryl group, a C6-C20 thing is preferable, for example, a phenyl group, a naphthyl group, etc. are mentioned. Examples of the group that can be substituted with the above alkyl group or aryl group include an alkyl group (for example, a methyl group, an n-propyl group, a t-amyl group, a t-octyl group, an n-nonyl group, a dodecyl group), an aryl group. (For example, phenyl group), nitro group, hydroxyl group, cyano group, sulfo group, alkoxy group (for example, methoxy group), aryloxy group (for example, phenoxy group), acyloxy group (for example, acetoxy group), Acylamino group (for example, acetylamino group), sulfonamide group (for example, methanesulfonamide group), sulfamoyl group (for example, methylsulfamoyl group), halogen atom (for example, fluorine atom, chlorine atom, bromine atom) ), Carboxy group, carbamoyl group (for example, methylcarbamoyl group, etc.), alkoxycarbonyl group (for example, metho Shiruboniru group), a sulfonyl group (e.g., methyl sulfonyl group). When there are two or more substituents, they may be the same or different. The total carbon number of the substituted alkyl group is preferably 1-20, and the total carbon number of the substituted aryl group is preferably 6-20.

The R _2, -COR ₃ (R ₃ is an alkyl group or an aryl group), - CONHR ₃ (R ₃ is an aryl group). a, b, and c are values representing the mass of each repeating unit in mol%, a is 40 to 86 mol%, b is 0 to 30 mol%, c is in the range of 0 to 60 mol%, and a + b + c = The number is 100 mol%, and particularly preferably, a is in the range of 50 to 86 mol%, b is in the range of 5 to 25 mol%, and c is in the range of 0 to 40 mol%. Each repeating unit having each composition ratio of a, b, and c may be composed of only the same one or may be composed of different ones.

As the polyurethane resin that can be used in the present invention, known resins such as polyester polyurethane, polyether polyurethane, polyether polyester polyurethane, polycarbonate polyurethane, polyester polycarbonate polyurethane, and polycaprolactone polyurethane can be used. For all of the polyurethane shown here, if _{necessary, -COOM, -SO 3 M, -OSO} 3 M, -P = O (OM) 2, -O-P = O (OM) 2, (M is hydrogen An atom or an alkali metal base), —N (R ₄ ) ₂ , —N + (R ₄ ) ₃ (R ₄ represents a hydrocarbon group, and a plurality of R ₄ may be the same or different), epoxy It is preferable to use one in which at least one polar group selected from a group, —SH, —CN and the like is introduced by copolymerization or addition reaction. The amount of such a polar group is 10 ⁻¹ to 10 ⁻⁸ mol / g, preferably 10 ⁻² to 10 ⁻⁶ mol / g. In addition to these polar groups, it is preferable to have at least one OH group in total, at least one at the end of the polyurethane molecule. Since OH groups are cross-linked with polyisocyanate which is a curing agent to form a three-dimensional network structure, it is more preferable that the OH groups are contained in the molecule. In particular, it is preferable that the OH group is at the molecular end because the reactivity with the curing agent is high. The polyurethane preferably has 3 or more OH groups at the molecular terminals, and particularly preferably 4 or more. When polyurethane is used, the glass transition temperature is preferably 70 to 105 ° C., the elongation at break is 100 to 2000%, and the stress at break is preferably 0.5 to 100 N / mm ² .

  In the present invention, the polymer compound represented by the general formula (V) is synthesized by a general synthesis method described in “vinyl acetate resin” edited by Ichiro Sakurada (Polymer Chemistry Publishing Society, 1962) and the like. Can do.

[Crosslinking agent]
In the present invention, it is known that the use of a crosslinking agent for the binder improves the film formation between the constituent layer and the support, or between the constituent layers, and reduces development unevenness. It also has the effect of suppressing the generation of printout silver after development.

  Examples of the crosslinking agent used in the present invention include various crosslinking agents conventionally used for silver halide photographic light-sensitive materials, such as aldehyde-based, epoxy-based, and ethyleneimine described in JP-A-50-96216. , Vinyl sulfone, sulfonic acid ester, acryloyl, carbodiimide, and silane compound crosslinking agents may be used.

(Color adjustment)
Next, the color tone of an image obtained by heat developing the imaging material will be described.

  Regarding the color tone of an output image for medical diagnosis such as a conventional X-ray photographic film, it is said that a cold tone image tone is easier for a reader to obtain a more accurate diagnostic observation result of a recorded image. Here, a cool image tone is a pure black tone or a bluish black tone with a black image, and a warm image tone is a black tone with a brown tone. However, in order to allow a more precise quantitative discussion, the following explanation is based on the expression recommended by the International Commission on Illumination (CIE).

Terminology of color "more Hiyacho" and "more temperature control" can be represented by the hue angle h _ab at the lowest density Dmin and optical density D = 1.0. That is, the hue angle h _ab represents the color coordinates a ^* and b ^* of the color space L ^* a ^* b ^* color space, which is a color space having a perceptually uniform rate recommended by the International Commission on Illumination (CIE) in 1976. Using the following formula.

h _ab = tan ⁻¹ (b ^* / a ^* )
As a result of the examination based on the expression method based on the hue angle, the color tone after development of the silver salt photothermographic imaging material according to the present invention preferably has a hue angle _hab range of 180 degrees < _hab <270 degrees. More preferably, it was found that 200 degrees < _hab <270 degrees, and most preferably 220 degrees < _hab <260 degrees. This is disclosed in Japanese Patent Application Laid-Open No. 2002-6463.

Conventionally, the CIE 1976 (L ^* u ^* v ^* ) color space or the (L ^* a ^* b ^* ) color space near the optical density of 1.0 is specified as u ^* , v ^* or a ^* , b ^* . It is known that a diagnostic image with a favorable visual color tone can be obtained by adjusting to a numerical value, and is described in, for example, Japanese Patent Application Laid-Open No. 2000-29164.

Furthermore, in the CIE 1976 (L ^* u ^* v ^* ) color space or (L ^* a ^* b ^* ) color space, various values are displayed on the graph with the horizontal axis u ^* or a ^* and the vertical axis v ^* or b ^*. When plotting u ^* , v ^* or a ^* , b ^* at various photographic densities to create a linear regression line, the linear regression line is adjusted to a specific range so that it is equivalent to or higher than a wet silver salt photosensitive material. It is possible to have a diagnostic property of Hereinafter, preferable range of conditions will be described.

1) The silver salt photothermographic dry imaging material was measured for the optical density 0.5, 1.0, 1.5 and the lowest optical density of the silver image obtained after the heat development processing, and CIE 1976 (L ^* u). ^* v ^* ) The linear regression line coefficient of determination (multiple determination) created by arranging u ^* and v ^* at the above optical densities on two-dimensional coordinates where the horizontal axis of the color space is u ^* and the vertical axis is v ^*. ) R ² is preferably 0.998 or more and 1.000 or less.

Furthermore, the v ^* value of the intersection with the vertical axis of the linear regression line is −5 or more and 5 or less, and the slope (v ^* / u ^* ) is 0.7 or more and 2.5 or less. preferable.

2) In addition, the optical density of the silver salt photothermographic dry imaging material of 0.5, 1.0, 1.5 and the lowest optical density were measured, and the side of the CIE 1976 (L ^* a ^* b ^* ) color space was measured. The coefficient of determination (multiple determination) R ^{2 of} the linear regression line created by arranging a ^* and b ^* at the above optical densities on two-dimensional coordinates with the axis a ^* and the vertical axis b ^* is 0.998. As mentioned above, it is preferable that it is 1.000 or less.

Furthermore, it is preferable that the b ^* value of the intersection with the vertical axis of the linear regression line is −5 or more and 5 or less, and the slope (b ^* / a ^* ) is 0.7 or more and 2.5 or less. .

An example of a method for creating the above-described linear regression line, that is, a method for measuring u ^* , v ^* and a ^* , b ^{* in} the CIE 1976 color space will be described next.

A four-stage wedge sample including an unexposed portion and optical densities of 0.5, 1.0, and 1.5 is prepared using a heat development apparatus. Each wedge density part thus produced is measured with a spectrocolorimeter (eg, CM-3600d; manufactured by Konica Minolta Sensing Co., Ltd.) to calculate u ^* , v ^* or a ^* , b ^* . The measurement conditions at that time are F7 light source as the light source, the viewing angle is 10 °, and the measurement is performed in the transmission measurement mode. Plot u ^* , v ^*, a ^* , b ^* measured on a graph with u ^* or a ^{* on} the horizontal axis and v ^* or b ^{* on the} vertical axis to obtain a linear regression line and determine coefficient (multiple determination) R ² Find the intercept and slope.

  Next, a specific method for obtaining a linear regression line having the above characteristics will be described.

  In the present invention, the developed silver shape is adjusted by adjusting the addition amount of the above-described toning agent, developer, silver halide grains, and compounds such as aliphatic carboxylic acid silver which are directly and indirectly involved in the development reaction process. Optimized and preferred color tone. For example, when the developed silver shape is dendritic, it becomes a bluish direction, and when it is a filament shape, it becomes a yellowish direction. That is, it can be adjusted in consideration of the tendency of the developed silver shape.

  Conventionally, phthalazinone or phthalazine and phthalic acids and phthalic anhydrides are generally used as toning agents. Examples of suitable toning agents are RD17029, U.S. Pat. Nos. 4,123,282, 3,994,732, 3,846,136, and 4,021,249. Is disclosed.

  In addition to such a toning agent, it is preferable to adjust the color tone by using a coupler disclosed in JP-A-11-288057, EP11334611A2 and the like and a leuco dye described in detail below.

  Further, by using silver halide grains that are converted into the internal latent image type after heat development according to the present invention, it is possible to unexpectedly prevent color tone fluctuations during storage of silver images.

[Leuco dye]
A leuco dye can be used in the silver salt photothermographic dry imaging material of the present invention.

  The leuco dye is preferably any colorless or slightly colored compound that is oxidized to a colored form when heated at a temperature of about 80-200 ° C. for about 0.5-30 seconds and is oxidized by silver ions. Any leuco dye that forms a pigment can be used. Compounds that are pH sensitive and can be oxidized to a colored state are useful.

  Representative leuco dyes suitable for use in the present invention are not particularly limited. For example, biphenol leuco dyes, phenol leuco dyes, indoanilin leuco dyes, acrylated azine leuco dyes, phenoxazine leuco dyes, phenodiazine leuco dyes. And dyes and phenothiazine leuco dyes. Also useful are U.S. Pat. Nos. 3,445,234, 3,846,136, 3,994,732, 4,021,249, 4,021, No. 250, No. 4,022,617, No. 4,123,282, No. 4,368,247, No. 4,461,681, and JP-A Nos. 50-36110 and 59. Leuco dyes disclosed in JP-A-206831, JP-A-5-204087, JP-A-11-231460, JP-A-2002-169249, JP-A-2002-236334, and the like.

  In order to adjust to a predetermined color tone, it is preferable to use leuco dyes of various colors singly or in combination of a plurality of types. In the present invention, the color tone is excessively yellowish with the use of a highly active reducing agent, or the image is excessively high at a high density portion of 2.0 or more by using fine silver halide. It is preferable to use a leuco dye that develops in cyan to prevent redness, but a yellow leuco dye and other leuco dyes that develop in cyan are also used for fine-tuning the color tone. It is preferable to do this.

  The color density is preferably adjusted appropriately in relation to the color tone of the developed silver itself. In the present invention, the sum of the maximum densities at the absorption maximum wavelength of the dye image formed with the leuco dye is usually 0.01 or more and 0.30 or less, preferably 0.02 or more and 0.20 or less, particularly preferably 0.8. It is preferable to adjust the color tone so that the color is developed so as to have a value of 02 or more and 0.10 or less and an image having a preferable color tone range described later is obtained.

(Yellow coloring leuco dye)
In the present invention, a color image forming agent represented by the following general formula (YL), which increases the absorbance at 360 to 450 nm when oxidized, is particularly preferably used as a yellow coloring leuco dye.

  Hereinafter, the compound represented by formula (YL) will be described in detail.

In the general formula (YL), the alkyl group represented by R ₁ is preferably an alkyl group having 1 to 30 carbon atoms, and may have a substituent. Specifically, methyl, ethyl, butyl, octyl, i-propyl, t-butyl, t-octyl, t-pentyl, sec-butyl, cyclohexyl, 1-methyl-cyclohexyl and the like are preferable, and steric rather than i-propyl. And a large group (for example, each group such as i-propyl, i-nonyl, t-butyl, t-amyl, t-octyl, cyclohexyl, 1-methyl-cyclohexyl, adamantyl, etc.), among them secondary A tertiary alkyl group is preferable, and tertiary alkyl groups such as t-butyl, t-octyl, and t-pentyl are particularly preferable. Examples of the substituent that R ₁ may have include a halogen atom, an aryl group, an alkoxy group, an amino group, an acyl group, an acylamino group, an alkylthio group, an arylthio group, a sulfonamide group, an acyloxy group, an oxycarbonyl group, and a carbamoyl group. , Sulfamoyl group, sulfonyl group, phosphoryl group and the like.

R ₂ represents a hydrogen atom, a substituted or unsubstituted alkyl group or an acylamino group, respectively. The alkyl group represented by R ₂ is preferably an alkyl group having 1 to 30 carbon atoms, and the acylamino group is preferably an acylamino group having 1 to 30 carbon atoms. Among these, the description of the alkyl group is the same as that for R ₁ .

The acylamino group represented by R ₂ may be unsubstituted or substituted, and specific examples include an acetylamino group, an alkoxyacetylamino group, and an aryloxyacetylamino group. R ₂ is preferably a hydrogen atom or an unsubstituted alkyl group having 1 to 24 carbon atoms, and specific examples include methyl, i-propyl, and t-butyl. R ₁ and R ₂ are not a 2-hydroxyphenylmethyl group.

R ₃ represents a hydrogen atom or a substituted or unsubstituted alkyl group. The alkyl group is preferably an alkyl group having 1 to 30 carbon atoms, and the description of the alkyl group is the same as that for R ₁ . R ₃ is preferably a hydrogen atom or an unsubstituted alkyl group having 1 to 24 carbon atoms, and specific examples include methyl, i-propyl, t-butyl and the like. Moreover, it is preferable that any one of R < ₁₂ >, R < ₁₃ > is a hydrogen atom.

R ₄ represents a group capable of substituting on the benzene ring and is, for example, the same group as described for the substituent R ₄ in the general formula (RED). R ₄ is preferably a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms or an oxycarbonyl group having 2 to 30 carbon atoms, more preferably an alkyl group having 1 to 24 carbon atoms. Examples of the substituent of the alkyl group include an aryl group, an amino group, an alkoxy group, an oxycarbonyl group, an acylamino group, an acyloxy group, an imide group, and a ureido group, and more preferable examples include an aryl group, an amino group, an oxycarbonyl group, and an alkoxy group. preferable. These alkyl group substituents may be further substituted with these substituents.

  Next, among the compounds represented by the general formula (YL), a compound (bisphenol compound) preferably used in the present invention is represented by the following general formula (YL ′).

In the general formula (YL ′), Z represents —S— or —C (R ₁ ) (R ₁ ′) —, and R ₁ and R ₁ ′ each represents a hydrogen atom or a substituent. Examples of the substituent represented by R ₁ and R ₁ ′ include the same groups as the substituents exemplified in the description of R _{1 in} the general formula (RED). R ₁ and R ₁ ′ are preferably a hydrogen atom or an alkyl group.

R ₂ , R ₃ , R ₂ ′ and R ₃ ′ each represent a substituent, and examples of the substituent include the same groups as those described for R ₂ and R ₃ in the general formula (RED).

R ₂ , R ₃ , R ₂ ′ and R ₃ ′ are preferably an alkyl group, alkenyl group, alkynyl group, aryl group or heterocyclic group, with an alkyl group being more preferred. Examples of the substituent on the alkyl group include the same groups as those described in the description of the substituent in the general formula (RED).

R ₂ , R ₃ , R ₂ ′ and R ₃ ′ are more preferably tertiary alkyl groups such as t-butyl, t-pentyl, t-octyl and 1-methyl-cyclohexyl.

R ₄ and R ₄ ′ each represent a hydrogen atom or a substituent, and examples of the substituent include the same groups as those described in the description of R ₄ in the general formula (RED).

  Examples of the compound (bisphenol compound) represented by the general formula (YL) include compounds (II-1) to (II-40) described in paragraphs “0032” to “0038” of JP-A No. 2002-169249, European Examples thereof include compounds (ITS-1) to (ITS-12) described in paragraph “0026” of Japanese Patent No. 1,211,093.

  Although the specific example of a compound represented by general formula (YL) below is shown, this invention is not limited to these.

  The addition amount of the compound represented by the general formula (YL) is usually 0.00001 to 0.01 mol, preferably 0.0005 to 0.01 mol, more preferably 0.001 to 1 mol per 1 mol of silver. 0.008 mol.

(Cyan coloring leuco dye)
Next, the cyan color-forming leuco dye will be described. In the present invention, a color image forming agent that increases its absorbance at 600 to 700 nm when oxidized is particularly preferably used as a cyan color developing dye. JP-A-59-206831 (in particular, λmax is 600 to 600 nm). Compounds within the range of 700 nm), compounds of general formula (I) to general formula (IV) of JP-A-5-204087 (specifically, (1) to (1) described in paragraphs “0032” to “0037”) 18) and compounds of general formula 4 to general formula 7 of JP-A No. 11-231460 (specifically, compounds of No. 1 to No. 79 described in paragraph “0105”).

  The cyan color-forming leuco dye particularly preferably used in the present invention is represented by the following general formula (CL).

In the general formula (CL), R ₁ and R ₂ are each a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, an alkenyl group, an alkoxy group, and R ₁₀ is an alkyl group, an aryl group, or a heterocyclic group. It may be an NHCO-R ₁₀ group, or R ₁ and R ₂ may be linked to each other to form an aliphatic hydrocarbon ring, an aromatic hydrocarbon ring or a heterocyclic ring. A is a —NHCO— group, —CONH— group or —NHCONH— group, R ₃ is a substituted or unsubstituted alkyl group, aryl group or heterocyclic group, or —A—R ₃ is a hydrogen atom. And W is a hydrogen atom or a —CONH—R ₅ group, a —CO—R ₅ group or a —CO—O—R ₅ group, wherein R ₅ is a substituted or unsubstituted alkyl group, aryl group or heterocyclic group. , R ₄ represents a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, an alkoxy group, a carbamoyl group, or a nitrile group. R ₆ is a —CONH—R ₇ group, a —CO—R ₇ group or a —CO—O—R ₇ group, wherein R ₇ is a substituted or unsubstituted alkyl group, aryl group or heterocyclic group. X represents a substituted or unsubstituted aryl group or heterocyclic group.

In the general formula (CL), the halogen atom is fluorine, bromine, chlorine or the like, the alkyl group is an alkyl group having up to 20 carbon atoms (for example, each group such as methyl, ethyl, butyl, dodecyl, etc.), and the alkenyl group Is an alkenyl group having up to 20 carbon atoms (eg, vinyl, allyl, butenyl, hexenyl, hexadienyl, ethenyl-2-propenyl, 3-butenyl, 1-methyl-3-propenyl, 3-pentenyl, 1-methyl-3 -Each group such as butenyl), an alkoxy group is an alkoxy group having up to 20 carbon atoms (for example, each group such as methoxy and ethoxy), and an aryl group is 6 carbon atoms such as phenyl, naphthyl and thienyl. -20 groups and heterocyclic groups are groups such as thiophene, furan, imidazole, pyrazole, pyrrole, etc. . A is a —NHCO— group, —CONH— group or —NHCONH— group, and R ₃ is a substituted or unsubstituted alkyl group (preferably up to 20 carbon atoms such as methyl, ethyl, butyl, dodecyl), an aryl group (preferably Is a phenyl group, naphthyl group, thienyl group, etc. having 6 to 20 carbon atoms) or a heterocyclic group (for example, each group such as thiophene, furan, imidazole, pyrazole, pyrrole, etc.), or -A-R ₃ is a hydrogen atom. , W is a hydrogen atom or an alkyl group in which R ₅ is substituted or unsubstituted (preferably up to 20 carbon atoms such as methyl, ethyl, butyl, dodecyl), aryl group (preferably having 6 to 20 carbon atoms, phenyl, naphthyl, thienyl) etc.) or a Hajime Tamaki (e.g., thiophene, furan, -CONH-R ₅ is an imidazole, pyrazole, each group of pyrrole, etc.) A -CO-R ₅ group or -CO-O-R ₅ group, R ₄ is a hydrogen atom, a halogen atom (e.g., fluorine, chlorine, bromine, iodine), chain or cyclic alkyl group (e.g., methyl Group, butyl group, dodecyl group, cyclohexyl group, etc.), alkoxy group (eg, methoxy group, butoxy group, tetradecyloxy group, etc.), carbamoyl group (eg, diethylcarbamoyl group, phenylcarbamoyl group, etc.), or nitrile group Among these, a hydrogen atom and an alkyl group are more preferable. R ₁ and R ₂ , R ₃ and R ₄ may be linked to each other to form a ring structure. The above groups may further have a single substituent or a plurality of substituents. For example, typical substituents that can be introduced into an aryl group include halogen atoms (fluorine, chlorine, bromine, etc.), alkyl groups ( Methyl, ethyl, propyl, butyl, dodecyl, etc.), hydroxyl group, cyano group, nitro group, alkoxy group (methoxy, ethoxy, etc.), alkylsulfonamide group (methylsulfonamide, octylsulfonamide, etc.), arylsulfonamide group (phenyl) Sulfonamides, naphthylsulfonamides, etc.), alkylsulfamoyl groups (butylsulfamoyl etc.), arylsulfamoyls (phenylsulfamoyl etc.), alkyloxycarbonyl groups (methoxycarbonyl etc.), aryloxycarbonyl groups (phenyl) Oxycarbonyl, etc.), aminosulfone Bromide group, an acylamino group, a carbamoyl group, a sulfonyl group, a sulfinyl group, a sulfoxy group, a sulfo group, an aryloxy group, an alkoxy group, an alkylcarbonyl group, an arylcarbonyl group include an amino group. Two different groups of these groups can be introduced into the aryl group. R ₁₀ or R ₈₅ is preferably a phenyl group, more preferably a phenyl group having a plurality of substituents including a halogen atom and a cyano group.

R ₆ is (methyl up to several preferably 20 carbon atoms, ethyl, butyl, dodecyl, etc.) R ₇ is a substituted or unsubstituted alkyl group, (phenyl preferably 6 to 20 carbon atoms, naphthyl, thienyl, etc.) an aryl group or A —CONH—R ₇ group, a —CO—R ₇ group or a —CO—O—R ₇ group which is a heterocyclic group (thiophene, furan, imidazole, pyrazole, pyrrole, etc.). As the substituent for the alkyl group represented by R _7, the same substituents as those for R _{1 to} R ₄ can be used. X ₈ represents a substituted or unsubstituted aryl group or heterocyclic group. Examples of the aryl group include groups having 6 to 20 carbon atoms such as phenyl, naphthyl, and thienyl, and examples of the heterocyclic group include thiophene, furan, imidazole, pyrazole, and pyrrole. As the substituent that the group represented by X can have, the same substituents as those in R _{1 to} R ₄ can be used. The group represented by X is preferably an aryl group or a heterocyclic group substituted with an alkylamino group (such as a diethylamino group) at the para position. These may contain photographically useful groups.

  Specific examples of the cyan chromogenic leuco dye (CL) are shown below, but are not limited thereto.

  The addition amount of the cyan coloring leuco dye is usually 0.00001 to 0.05 mol / Ag1 mol, preferably 0.0005 to 0.02 mol / Ag1 mol, more preferably 0.001 to 0.01 mol. / Ag1 mol.

  As a method for adding the compound represented by the general formula (YL) and the cyan color-forming leuco dye, it can be added in the same manner as the method for adding the reducing agent represented by the general formula (RED), You may make it contain in a coating liquid by arbitrary methods, such as an emulsified dispersion form and a solid fine particle dispersion form, and may make it contain in a photosensitive material.

  The compound of the general formula (YL) and the cyan color-forming leuco dye are preferably contained in an image forming layer containing an organic silver salt, but one is in the image forming layer and the other is adjacent to the image forming layer. You may make it contain in a forming layer, and may make both contain in a non-image forming layer. Further, when the image forming layer is composed of a plurality of layers, they may be contained in separate layers.

[Coating aids, etc.]
In the present invention, the surface layer of the silver salt photothermographic dry imaging material (when the photosensitive layer side or the non-photosensitive layer is provided on the opposite side of the photosensitive layer with the support sandwiched) is handled before development. It is preferable to contain a matting agent in order to prevent scratches on the image after heat development, and 0.1 to 30% by mass with respect to the binder.

  The material of the matting agent may be either organic or inorganic. Examples of inorganic substances include silica described in Swiss Patent No. 330,158 and the like, glass powder described in French Patent No. 1,296,995 and the like, and alkali described in British Patent No. 1,173,181 and the like. Earth metals or carbonates such as cadmium and zinc can be used as the matting agent. Examples of organic substances include starch described in U.S. Pat. No. 2,322,037 and the like, starch derivatives described in Belgian Patent 625,451 and British Patent 981,198, and Japanese Patent Publication No. 44-3643. Polyvinyl alcohol described, polystyrene or polymethacrylate described in Swiss Patent No. 330,158, polyacrylonitrile described in US Pat. No. 3,079,257, US Pat. No. 3,022,169 etc. An organic matting agent such as a polycarbonate can be used.

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

  Here, the variation coefficient of the particle size distribution is a value represented by the following equation.

(Standard deviation of particle size) / (Average value of particle size) × 100
The method for adding the matting agent according to the present invention may be a method in which the matting agent is dispersed and applied in advance in the coating solution, or a method in which the matting agent is sprayed after the coating solution is applied and before drying is completed. May be. When a plurality of types of matting agents are added, both methods may be used in combination.

[Fluorosurfactant]
In the imaging material of this invention, it is preferable to use the fluorine-type surfactant represented by the following general formula (SA-1)-(SA-3).

General formula (SA-1)
(Rf-L) _p -Y- (A) _q
General formula (SA-2)
LiO ₃ S— (CF ₂ ) _n —SO ₃ Li
General formula (SA-3)
_{MO 3 S- (CF 2) n} -SO 3 M
In the formula, M represents a hydrogen atom, a sodium atom, a potassium atom or an ammonium group, and n represents a positive integer, but when M = H, n = 1 to 6 and 8, and when M = Na, n = 4, n = 1 to 6 when M = K, and n = 1 to 8 when M = ammonium group.

  In the general formula (SA-1), Rf represents a substituent containing a fluorine atom. Examples of the substituent containing a fluorine atom include an alkyl group having 1 to 25 carbon atoms (for example, a methyl group, an ethyl group, and the like). Group, butyl group, octyl group, dodecyl group, octadecyl group and the like) or alkenyl group (for example, propenyl group, butenyl group, nonenyl group, dodecenyl group, etc.) and the like.

  L represents a divalent linking group having no fluorine atom. Examples of the divalent linking group having no fluorine atom include an alkylene group (for example, methylene group, ethylene group, butylene group, etc.), alkylene Oxy group (methyleneoxy group, ethyleneoxy group, butyleneoxy group, etc.), oxyalkylene group (for example, oxymethylene group, oxyethylene group, oxybutylene group, etc.), oxyalkyleneoxy group (for example, oxymethyleneoxy group, oxy Ethyleneoxy group, oxyethyleneoxyethyleneoxy group, etc.), phenylene group, oxyphenylene group, phenyloxy group, oxyphenyloxy group, or a combination of these groups.

  A represents an anionic group or a base thereof, for example, a carboxylic acid group or a base thereof (sodium salt, potassium salt and lithium salt), a sulfonic acid group or a base thereof (sodium salt, potassium salt and lithium salt) and a phosphoric acid group or Examples thereof include sodium base and potassium salt.

  Y represents a trivalent or tetravalent linking group having no fluorine atom. For example, an atom composed of a trivalent or tetravalent linking group having no fluorine atom and centering on a carbon atom or a nitrogen atom. Groups. p represents an integer of 1 to 3, and q represents an integer of 2 to 3.

  The fluorine-based surfactant represented by the general formula (SA-1) is an alkyl compound having 1 to 25 carbon atoms into which a fluorine atom has been introduced (for example, trifluoromethyl group, pentafluoroethyl group, perfluorobutyl group, perfluorobutyl group, A compound having a fluorooctyl group and a perfluorooctadecyl group) and an alkenyl compound (for example, a perfluorohexenyl group and a perfluorononenyl group), and a trivalent to hexavalent alkanol compound in which no fluorine atom is introduced, An anionic group (A) is further added to a compound (partially Rf-modified alkanol compound) obtained by addition reaction or condensation reaction with an aromatic compound or hetero compound having 3 to 4 hydroxyl groups, for example by sulfate esterification. It can be obtained by introduction.

  Examples of the trivalent to hexavalent alkanol compound include glycerin, pentaerythritol, 2-methyl-2-hydroxymethyl 1,3-propanediol, 2,4-dihydroxy-3-hydroxymethylpentene, and 1,2,6-hexane. Examples include triol, 1,1,1-tris (hydroxymethyl) propane, 2,2-bis (butanol) -3, aliphatic triol, tetramethylolmethane, D-sorbitol, xylitol, D-mannitol and the like.

  Examples of the aromatic compound and hetero compound having 3 to 4 hydroxyl groups include 1,3,5-trihydroxybenzene and 2,4,6-trihydroxypyridine.

  N in general formula (SA-2) represents the integer of 1-4.

  In general formula (SA-3), M represents a hydrogen atom, a sodium atom, a potassium atom, or an ammonium group, n represents a positive integer, and when M = H, n = 1 to 6 and 8; When n = Na, n = 4, when M = K, n = 1-6, and when M = ammonium group, n = 1-8.

  As a method of adding the fluorine-based surfactant represented by the general formulas (SA1) to (SA-3) to the coating solution, it can be added according to a known addition method. That is, it can be dissolved and added in alcohols such as methanol and ethanol, ketones such as methyl ethyl ketone and acetone, polar solvents such as dimethyl sulfoxide and dimethylformamide. Further, fine particles of 1 μm or less can be dispersed in water or an organic solvent by sand mill dispersion, jet mill dispersion, ultrasonic dispersion or homogenizer dispersion, and added. Many techniques for fine particle dispersion are disclosed, but they can be dispersed according to these techniques. The fluorosurfactant is preferably added to the outermost protective layer.

The amount of the fluorosurfactant added is preferably 1 × 10 ⁻⁸ to 1 × 10 ⁻¹ mol per 1 m ^2, particularly preferably 1 × 10 ⁻⁵ to 1 × 10 ⁻² mol. If it is less than the former range, charging characteristics cannot be obtained, and if it exceeds the former range, the humidity dependence is large and the storage stability under high humidity deteriorates.

  Note that surfactants represented by the general formula (SA-1), the general formula (SA-2), and the general formula (SA-3) are disclosed in JP-A-2003-57786, Japanese Patent Application No. 2002-178386, and JP-A-2002-237882, respectively. Is disclosed.

  Examples of the support material used in the silver salt photothermographic dry imaging material of the present invention include various polymer materials, glass, wool cloth, cotton cloth, paper, metal (for example, aluminum), etc. In terms of handling, a material that can be processed into a flexible sheet or roll is suitable. Therefore, as a support in the silver salt photothermographic dry imaging material of the present invention, a plastic film (for example, cellulose acetate film, polyester film, polyethylene terephthalate film, polyethylene naphthalate film, polyamide film, polyimide film, cellulose triacetate film or polycarbonate film). Etc.) is preferred, and in the present invention, a biaxially stretched polyethylene terephthalate film is particularly preferred. The thickness of the support is about 50 to 300 μm, preferably 70 to 180 μm.

  In the present invention, a conductive compound such as a metal oxide and / or a conductive polymer can be included in the constituent layers in order to improve the chargeability. These may be contained in any layer, but are preferably contained in an undercoat layer, a backing layer, a layer between the photosensitive layer and the undercoat, and the like. In the present invention, the conductive compounds described in US Pat. No. 5,244,773, columns 14 to 20 are preferably used.

  The silver salt photothermographic dry imaging material of the present invention has at least one photosensitive layer on a support. Although only the photosensitive layer may be formed on the support, it is preferable to form at least one non-photosensitive layer on the photosensitive layer. For example, a protective layer is provided on the photosensitive layer for the purpose of protecting the photosensitive layer, and on the opposite side of the support, to prevent sticking between the photosensitive materials or in the photosensitive material roll. A layer is preferably provided. Binders used in these protective layers and backcoat layers have a glass transition point higher than that of the heat-developable layer, and polymers such as scratches and deformations, such as cellulose acetate and cellulose acetate butyrate, are the above-mentioned binders. It is chosen from among them. For gradation adjustment and the like, in the present invention, the photosensitive layer is preferably composed of two or more layers. For example, two or more photosensitive layers may be provided on one side of the support, or the support. One or more layers may be installed on both sides.

  In the silver salt photothermographic dry imaging material of the present invention, a filter layer is formed on the same side as or opposite to the photosensitive layer in order to control the amount of light transmitted through the photosensitive layer or the wavelength distribution. It is preferable to contain a dye or pigment in the layer.

  For example, when the silver salt photothermographic dry imaging material of the present invention is used as an image recording material by infrared light, a squarylium dye having a thiopyrylium nucleus and a pyrylium nucleus as disclosed in Japanese Patent Application No. 11-255557 are used. It is preferable to use a squarylium dye having a thiopyrylium croconium dye or a pyrylium croconium dye similar to the squarylium dye.

  The compound having a squarylium nucleus is a compound having 1-cyclobutene-2-hydroxy-4-one in the molecular structure, and the compound having a croconium nucleus is 1-cyclopentene-2-hydroxy- in the molecular structure. It is a compound having 4,5-dione. Here, the hydroxyl group may be dissociated. Hereinafter, in the present specification, these pigments are collectively referred to as squarylium dyes for convenience.

  As the dye, a compound described in JP-A-8-201959 is also preferable.

[Layer structure and coating conditions]
The silver salt photothermographic dry imaging material of the present invention is formed by preparing a coating solution in which the above-described constituent layers are dissolved or dispersed in a solvent, and applying a plurality of these coating solutions simultaneously, followed by heat treatment. It is preferable. Here, "multiple simultaneous multi-layer coating" means that a coating solution for each constituent layer (for example, a photosensitive layer and a protective layer) is prepared, and each layer is repeatedly coated and dried when it is coated on a support. Rather, it means that each constituent layer can be formed in such a state that a multilayer coating and drying process can be performed simultaneously.

  There are no particular restrictions on the method of applying multiple layers of each constituent layer simultaneously, and for example, a known method such as a bar coater method, curtain coating method, dipping method, air knife method, hopper coating method, or extrusion coating method may be used. Can do. Of these, a pre-weighing type coating method called an extrusion coating method is more preferable. Since the extrusion coating method does not volatilize on the slide surface unlike the slide coating method, it is suitable for precision coating and organic solvent coating. Although this coating method has been described on the side having the photosensitive layer, the same applies to the case of coating with undercoating when providing the backcoat layer.

In the present invention, the silver coating amount is preferably 0.5 g / m ² or more and 2.0 g / m ² or less, more preferably 1.0 g / m ² or more and 1.5 g / m ² or less.

In the present invention, the silver equivalent of silver halide grains having a grain size of 0.030 μm or more and 0.055 μm or less in the silver halide grain emulsion has a silver coating amount of 0.5 g / m ² or more and 1.5 g. It is preferably 3% or more and 15% or less in the range of / m ² or less.

  Among the applied silver amount, those derived from silver halide preferably occupy 2 to 18%, more preferably 3 to 15%, based on the total silver amount.

In the present invention, the coating density of silver halide grains of 0.01 μm or more (equivalent particle diameter equivalent to sphere) is preferably 1 × 10 ¹⁴ particles / m ² or more and 1 × 10 ¹⁸ particles / m ² or less. Furthermore, 1 × 10 ¹⁵ pieces / m ² or more and 1 × 10 ¹⁷ pieces / m ² or less are preferable.

Further, the coating density of the aliphatic carboxylic acid silver salt of the present invention is 1 × 10 ⁻¹⁷ g or more and 1 × 10 ⁻¹⁵ g or less per silver halide grain of 0.01 μm or more (equivalent particle diameter equivalent to sphere). Furthermore, it is preferably 1 × 10 ⁻¹⁶ g or more and 1 × 10 ⁻¹⁴ g or less.

  When coated under the conditions within the above range, it is preferable from the viewpoint of the optical maximum density of the silver image per fixed coated silver amount, that is, the silver coating amount (covering power) and the color tone of the silver image. Results are obtained.

[Exposure conditions]
In the exposure of the silver salt photothermographic dry imaging material of the present invention, it is desirable to use an appropriate light source for the color sensitivity imparted to the photosensitive material. For example, when the photosensitive material is sensitive to infrared light, it can be applied to any light source as long as it is in the infrared light range. However, the laser power is high and the photosensitive material can be transparent. In view of the above, an infrared semiconductor laser (780 nm, 820 nm) is more preferably used.

  In the present invention, the exposure is preferably performed by laser scanning exposure, but various methods can be adopted as the exposure method. For example, as a first preferred method, there is a method using a laser scanning exposure machine in which the angle formed by the exposure surface of the photosensitive material and the scanning laser beam is not substantially perpendicular.

  Here, “substantially not perpendicular” means that the angle closest to the vertical during laser scanning is preferably 55 degrees or more and 88 degrees or less, more preferably 60 degrees or more and 86 degrees or less, and further Preferably it is 65 degrees or more and 84 degrees or less, Most preferably, it is 70 degrees or more and 82 degrees or less.

  The beam spot diameter on the photosensitive material exposure surface when the laser beam is scanned onto the photosensitive material is preferably 200 μm or less, more preferably 100 μm or less. This is preferable in that the smaller the spot diameter, the smaller the angle of deviation of the laser incident angle from the vertical. The lower limit of the beam spot diameter is 10 μm. By performing such laser scanning exposure, it is possible to reduce image quality deterioration related to reflected light such as generation of interference fringe-like unevenness.

  As a second method, it is preferable to perform exposure using a laser scanning exposure machine that emits scanning laser light that is a vertical multi. Compared with a longitudinal single mode scanning laser beam, image quality degradation such as occurrence of interference fringe-like unevenness is reduced.

  In order to make it vertically multi-ply, methods such as using return light by multiplexing and applying high-frequency superposition are preferable. The vertical multi means that the exposure wavelength is not single, and the distribution of the exposure wavelength is usually 5 nm or more, preferably 10 nm or more. The upper limit of the exposure wavelength distribution is not particularly limited, but is usually about 60 nm.

In the image recording methods of the first and second aspects described above, the laser used for the scanning exposure is generally well-known solid laser such as ruby laser, YAG laser, glass laser; HeNe laser, Ar ion. Gas laser such as laser, Kr ion laser, CO ₂ laser, CO laser, HeCd laser, N ₂ laser, excimer laser; InGaP laser, AlGaAs laser, GaAsP laser, InGaAs laser, InAsP laser, CdSnP ₂ laser, GaSb laser, etc. Semiconductor lasers; chemical lasers, dye lasers, and the like can be selected and used in a timely manner, but among these, it is preferable to use a semiconductor laser having a wavelength of 600 to 1200 nm from the viewpoint of maintenance and the size of the light source. However, a semiconductor laser having an emission peak intensity in the range of 390 nm to 430 nm can also be used when the present invention is applied to a photosensitive material that utilizes the inherent photosensitive characteristics of silver halide grains.

  In addition, in a laser used in a laser imager or a laser image setter, the beam spot diameter on the material exposure surface when scanned with a silver salt photothermographic dry imaging material is generally 5 to 75 μm as a minor axis diameter, The major axis diameter is in the range of 5 to 100 μm, and the laser beam scanning speed can be set to an optimum value for each photosensitive material depending on the sensitivity and laser power at the laser oscillation wavelength unique to the silver salt photothermographic dry imaging material.

[Development conditions]
In the present invention, development conditions vary depending on the equipment, equipment, or means used, but typically involve heating the imagewise exposed silver salt photothermographic dry imaging material at a suitable high temperature. . The latent image obtained after exposure is obtained by heating the silver salt photothermographic dry imaging material at a moderately high temperature (eg, about 100-200 ° C.) for a sufficient time (generally about 1 second to about 2 minutes). It can be developed. When the heating temperature is 100 ° C. or lower, sufficient image density cannot be obtained in a short time, and when the heating temperature is 200 ° C. or higher, the binder melts, and not only the image itself but also the transportability and the developing machine are adversely affected, such as transfer to a roller. Effect. By heating, a silver image is generated by an oxidation-reduction reaction between silver ions (which function as an oxidizing agent) supplied from an aliphatic carboxylic acid silver salt or the like and a reducing agent. This reaction process proceeds without any supply of treatment liquid such as water from the outside.

  The heating device, apparatus, and means may be a heating means typical as a heat generator using a hot plate, iron, hot roller, carbon, white titanium, or the like. More preferably, in the silver salt photothermographic dry imaging material provided with the protective layer of the present invention, the surface having the protective layer is brought into contact with the heating means and the heat treatment is performed for uniform heating and thermal efficiency. From the viewpoint of workability and the like, it is preferable that the surface is conveyed while being brought into contact with a heat roller, heated and developed.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto.

Example 1
<< Production of Photosensitive Material 101 >>
[Preparation of underdrawn support]
Corona discharge of 8 W · min / m ² on both sides of a biaxially stretched heat-fixed polyethylene terephthalate film with an optical density of 0.170 (measured with a Densitometer PDA-65 manufactured by Konica Minolta Photo Imaging Co., Ltd.). The processed photographic support was subjected to a subbing process according to the following method.

On one surface of the photographic support, the undercoat coating solution a-1 was applied at 22 ° C. and 100 m / min so that the dry film thickness was 0.2 μm, and dried at 140 ° C. to form an image forming layer. A side undercoat layer was formed (hereinafter referred to as undercoat underlayer A-1). Also, as the backing layer undercoat layer on the opposite side, the following undercoat coating solution b-1 was applied at 22 ° C. and 100 m / min so that the dry film thickness was 0.12 μm, and dried at 140 ° C. Then, an undercoat conductive layer having an antistatic function (hereinafter referred to as undercoat lower layer B-1) was applied to the backing layer side. After the corona discharge of 8 W · min / m ² is applied to each surface of the undercoat lower layer A-1 and the undercoat lower layer B-1, the following undercoat coating solution a-2 is applied on the undercoat lower layer A-1. Is coated at 33 ° C. and 100 m / min so as to have a dry film thickness of 0.03 μm, and dried at 140 ° C. to form an undercoat upper layer A-2. The undercoating liquid b-2 was applied at 33 ° C. and 100 m / min so as to have a dry film thickness of 0.2 μm, dried at 140 ° C. to form an undercoating upper layer B-2, and further supported at 123 ° C. for 2 minutes. The body was heat-treated and wound up under conditions of 25 ° C. and 50% RH to prepare a substrate with an underdrawn.

(Preparation of undercoat coating liquid a-1: image forming layer side undercoat A-1)
Acrylic polymer latex C-3 (solid content 30%) 70.0 g
5.0 g aqueous dispersion of ethoxylated alcohol and ethylene homopolymer (solid content 10%)
Surfactant (A) 0.1g
Distilled water was added to make 1000 ml, and a coating solution was obtained.

(Preparation of undercoating liquid a-2: Image forming layer side undercoating upper layer A-2)
Modified aqueous polyester B-2 (18% by mass) 30.0 g
Surfactant (A) 0.1g
True spherical silica matting agent (Nippon Shokubai Co., Ltd. Sea Hoster KE-P50) 0.04g
Distilled water was added to make 1000 ml, and a coating solution was obtained.

(Preparation of undercoat coating solution b-1: backing layer side undercoat layer B-1)
Acrylic polymer latex C-1 (solid content 30%) 30.0 g
Acrylic polymer latex C-2 (solid content 30%) 7.6 g
SnO ₂ sol (* 1) 180g
Surfactant (A) 0.5g
PVA-613 (PVA manufactured by Kuraray Co., Ltd.) 5% by weight aqueous solution 0.4 g
Distilled water was added to make 1000 ml, and a coating solution was obtained.

* 1: The SnO ₂ sol synthesized by the method described in Example 1 of Japanese Examined Patent Publication No. 35-6616 was heated and concentrated to a solid content concentration of 10% by mass, and then adjusted to pH = 10 with aqueous ammonia. (Preparation of subbing coating solution b-2: backing layer side subbing upper layer B-2)
Modified aqueous polyester B-1 (18% by mass) 145.0 g
True spherical silica matting agent (Nippon Shokubai Co., Ltd. Sea Hoster KE-P50) 0.2g
Surfactant (A) 0.1g
Distilled water was added to make 1000 ml, and a coating solution was obtained.

  The modified aqueous polyester B-1 and B-2 solutions and acrylic polymer latexes C-1 to C-3 used for the preparation of the above undercoat coating solution were prepared according to the following method.

<Preparation of aqueous polyester A-1 solution>
35.4 parts by weight of dimethyl terephthalate, 33.63 parts by weight of dimethyl isophthalate, 17.92 parts by weight of dimethyl sodium 5-sulfoisophthalate, 62 parts by weight of ethylene glycol, 0 of calcium acetate monohydrate 0.06 parts by mass, 0.022 parts by mass of manganese acetate tetrahydrate was subjected to a transesterification reaction while distilling off methanol at 170 to 220 ° C. in a nitrogen stream, and then 0.04 mass of trimethyl phosphate. Part, 0.04 parts by weight of antimony trioxide as a polycondensation catalyst and 6.8 parts by weight of 1,4-cyclohexanedicarboxylic acid were added, and a theoretical amount of water was distilled off at a reaction temperature of 220 to 235 ° C. Esterification was performed.

  Thereafter, the inside of the reaction system was further depressurized and heated over about 1 hour, and finally subjected to polycondensation at 280 ° C. and 133 Pa or less for about 1 hour to synthesize aqueous polyester A-1. The obtained aqueous polyester A-1 had an intrinsic viscosity of 0.33, an average particle size of 40 nm, and Mw = 80000 to 100,000.

  Next, 850 ml of pure water was put into a 2 L three-necked flask equipped with a stirring blade, a reflux condenser, and a thermometer, and 150 g of aqueous polyester A-1 was gradually added while rotating the stirring blade. After stirring for 30 minutes at room temperature, the mixture was heated to an internal temperature of 98 ° C. over 1.5 hours and dissolved at this temperature for 3 hours. After completion of the heating, the mixture was cooled to room temperature over 1 hour and allowed to stand overnight to prepare a 15% by mass aqueous polyester A-1 solution.

<Preparation of modified aqueous polyester B-1 and B-2 solutions>
Into a 3 L four-necked flask equipped with a stirring blade, a reflux condenser, a thermometer and a dropping funnel, 1900 ml of the 15% by mass aqueous polyester A-1 solution was placed, and the internal temperature was adjusted to 80 ° C. while rotating the stirring blade. Until heated. Into this, 6.52 ml of a 24% aqueous solution of ammonium peroxide was added, and a monomer mixture (28.5 g of glycidyl methacrylate, 21.4 g of ethyl acrylate, 21.4 g of methyl methacrylate) was dropped over 30 minutes, The reaction is continued for another 3 hours. Then, it cooled and filtered to 30 degrees C or less, and prepared the modified aqueous polyester B-1 solution (vinyl-type component modification | denaturation ratio 20 mass%) whose solid content concentration is 18 mass%.

  Next, the modified aqueous polyester B- was used except that the vinyl modification ratio was 36% by mass, and the modified components were styrene: glycidyl methacrylate: acetoacetoxyethyl methacrylate: n-butyl acrylate = 39.5: 40: 20: 0.5. In the same manner as in Preparation 1, a modified aqueous polyester B-2 solution (vinyl component modification ratio 20 mass%) having a solid content concentration of 18 mass% was prepared.

<Preparation of acrylic polymer latex C-1 to C-3>
Acrylic polymer latexes C-1 to C-3 having the monomer composition shown in Table 1 were synthesized by emulsion polymerization. The solid content concentration was 30% by mass.

[Formation of antihalation layer]
The antihalation layer was coated by applying an antihalation layer coating solution having the following composition onto the undercoating upper layer A-2 of the undercoated support prepared above and drying.

<Anti-halation layer coating solution>
Binder: PVB-1 (* 2) 0.8 g / m ²
Dye: C1 1.2 × 10 ⁻⁵ mol / m ²
* 2: The binder used was polyvinyl butyral (PVB-1) dissolved in methyl ethyl ketone (MEK). PVB-1 was obtained by saponifying 98% polyvinyl acetate having a polymerization degree of 500 and then butylating 86% of the remaining hydroxyl groups.

[Formation of backing layer and protective layer]
On the other hand, a backing layer prepared by applying a backing layer coating liquid having the following composition onto the undercoating upper layer B-2 of the prepared undercoated support so that the applied amount (per 1 m ² ) satisfies the following conditions. And each coating liquid for the protective layer is sequentially applied and dried to form a backing layer and a protective layer.

<Backing layer coating solution>
Binder: PVB-1 (supra) 1.8g
Dye: C1 1.2 × 10 ⁻⁵ mol <Protective layer coating solution>
Cellulose acetate butyrate 1.1g
Matting agent (polymethyl methacrylate: average particle size 5 μm) 0.12 g
Antistatic agent: F-EO 250mg
Antistatic agent: F-DS1 30mg

(Formation of image forming layer)
[Preparation of photosensitive silver halide emulsion]
(Preparation of photosensitive silver halide emulsion 1)
<Solution A1>
Phenylcarbamoylated gelatin 88.3g
Compound A (* 3) (10% methanol aqueous solution) 10 ml
Potassium bromide 0.32g
Finish to 5429 ml with water <Solution B1>
0.67 mol / L silver nitrate aqueous solution 2635 ml
<Solution C1>
Potassium bromide 51.55g
Potassium iodide 1.47g
Finish to 660 ml with water <Solution D1>
Potassium bromide 154.9g
4.41 g of potassium iodide
K ₃ IrCl ₆ (equivalent to 4 × 10 ⁻⁵ mol / Ag) 50.0 ml
Finish to 1982 ml with water <Solution E1>
0.4 mol / L potassium bromide aqueous solution The following silver potential control amount <Solution F1>
Potassium hydroxide 0.71g
Finish to 20 ml with water <Solution G1>
56% acetic acid aqueous solution 18.0 ml
<Solution H1>
Anhydrous sodium carbonate 1.72 g
Finish to 151 ml with water (* 3) Compound A:
_{HO (CH 2 CH 2 O)} n (CH (CH 3) CH 2 O) 17 (CH 2 CH 2 O) m H
(M + n = 5-7)
Using a mixing stirrer described in Japanese Patent Publication No. 58-58288, the solution A1 was adjusted to 4 by simultaneous mixing while controlling the 1/4 amount of the solution B1 and the total amount of the solution C1 to 32 ° C. and pAg 8.09. Addition took 45 minutes to nucleate. After 1 minute, the entire amount of solution F1 was added. During this time, the pAg was adjusted as appropriate using the solution E1. After 6 minutes, 3/4 amount of the solution B1 and the total amount of the solution D1 were added over 14 minutes and 15 seconds by the simultaneous mixing method while controlling the temperature at 32 ° C. and pAg 8.09. After stirring for 5 minutes, the temperature was raised to 40 ° C., and the entire amount of the solution G1 was added to precipitate the silver halide emulsion. The supernatant was removed leaving 2000 ml of the sedimented portion, 10 L of water was added, and after stirring, the silver halide emulsion was sedimented again. The remaining portion of 1500 ml was left, the supernatant was removed, 10 L of water was further added, and after stirring, the silver halide emulsion was allowed to settle. After leaving 1500 ml of the sedimented portion and removing the supernatant, the solution H1 was added, the temperature was raised to 60 ° C., and the mixture was further stirred for 120 minutes. Finally, the pH was adjusted to 5.8, and water was added so that the amount was 1161 g per mole of silver to obtain an emulsion.

  This emulsion was monodispersed cubic silver iodobromide grains having an average grain size of 0.040 μm, a grain size variation coefficient of 12%, and a [100] face ratio of 92%.

[Preparation of photosensitive layer coating solution]
(Preparation of powdered aliphatic carboxylic acid silver salt A)
In 4720 ml of pure water, 117.7 g of behenic acid, 60.9 g of arachidic acid, 39.2 g of stearic acid and 2.1 g of palmitic acid were dissolved at 80 ° C. Next, 486.2 ml of a 1.5 mol / L potassium hydroxide aqueous solution was added, and 6.2 ml of concentrated nitric acid was added, followed by cooling to 55 ° C. to obtain a fatty acid potassium solution. While maintaining the temperature of the fatty acid potassium solution at 55 ° C., 347 ml of t-butyl alcohol was added and stirred for 20 minutes, and then 45.3 g of the above photosensitive silver halide emulsion 1 and 450 ml of pure water were added, Stir for 5 minutes.

  Next, 702.6 ml of a 1 mol / L silver nitrate solution was added over 2 minutes and stirred for 10 minutes to obtain an aliphatic carboxylic acid silver salt dispersion. Thereafter, the obtained aliphatic carboxylic acid silver salt dispersion was transferred to a water-washing vessel, deionized water was added and stirred, and then allowed to stand to float and separate the aliphatic carboxylic acid silver salt dispersion. Was removed. Thereafter, washing with deionized water and drainage were repeated until the electrical conductivity of the drainage reached 50 μS / cm, and centrifugal dehydration was carried out. Using a dryer (manufactured by Seishin Enterprise Co., Ltd.), drying is performed until the water content becomes 0.1% according to the operating conditions of the nitrogen gas atmosphere and the hot air temperature at the dryer entrance, to obtain a powdered aliphatic carboxylic acid silver salt A It was. An infrared moisture meter was used to measure the water content of the aliphatic carboxylic acid silver salt composition. The silveration rate of the aliphatic carboxylic acid silver was confirmed to be about 95% by the method described above.

(Preparation of preliminary dispersion A)
14.57 g of polyvinyl butyral resin is dissolved in 1457 g of methyl ethyl ketone (hereinafter abbreviated as MEK), and the powdered aliphatic carboxylic acid silver salt A is stirred with a dissolver DISPERMAT CA-40M manufactured by VMA-GETZMANN. Was added gradually and mixed well to prepare a preliminary dispersion A.

(Preparation of photosensitive emulsion dispersion A)
Media type dispersion filled with 80% of the internal volume of 0.5 mm diameter zirconia beads (Toreceram manufactured by Toray Industries, Inc.) using the prepared preliminary dispersion A so that the residence time in the mill is 1.5 minutes using a pump. A photosensitive emulsion dispersion A was prepared by supplying to a machine DISPERMAT SL-C12EX type (manufactured by VMA-GETZMANN) and dispersing at a mill peripheral speed of 8 m / s.

(Preparation of stabilizer solution)
A stabilizer solution was prepared by dissolving 1.0 g of Stabilizer 1 and 0.31 g of potassium acetate in 4.97 g of methanol.

(Preparation of infrared sensitizing dye liquid A)
19.2 mg of infrared sensitizing dye 1, 10 mg of infrared sensitizing dye 2, 1.48 g of 2-chloro-benzoic acid, 2.78 g of stabilizer 2 and 365 mg of 5-methyl-2-mercaptobenzimidazole Was dissolved in 31.3 ml of MEK in the dark to prepare an infrared sensitizing dye solution A.

(Preparation of additive solution a)
27.98 g and 1.54 g of 4-methylphthalic acid as 1,1-bis (2-hydroxy-3,5-dimethylphenyl) -3,5,5-trimethylhexane (developer A) as a developer, 0 20 g of infrared dye 1 was dissolved in 110 g of MEK to obtain additive solution a.

(Preparation of additive liquid b)
3.56 g of antifoggant 2 and 3.43 g of phthalazine were dissolved in 40.9 g of MEK to obtain additive solution b.

(Preparation of photosensitive layer coating liquid A)
In an inert gas atmosphere (nitrogen 97%), the photosensitive emulsion dispersion A (50 g) and 15.11 g of MEK were kept at 21 ° C. with stirring, and 390 μl of antifoggant 1 (10% methanol solution) was added. Added and stirred for 1 hour. Further, 494 μl of calcium bromide (10% methanol solution) was added and stirred for 20 minutes. Subsequently, 167 ml of the stabilizer solution was added and stirred for 10 minutes, and then 1.32 g of the infrared sensitizing dye solution A was added and stirred for 1 hour. Thereafter, the temperature was lowered to 13 ° C. and further stirred for 30 minutes. While keeping the temperature at 13 ° C., 13.31 g of polyvinyl acetal resin as a binder resin was added and stirred for 30 minutes, and then 1.084 g of tetrachlorophthalic acid (9.4 mass% MEK solution) was added and stirred for 15 minutes. . Further, while continuing stirring, 12.43 g of additive solution a, 1.6 ml of Desmodur N3300 / Mobey aliphatic isocyanate (10% MEK solution), and 4.27 g of additive solution b were sequentially added and stirred for photosensitivity. An aqueous layer coating solution A was obtained.

[Preparation of surface protective layer]
A surface protective layer coating solution was prepared so that each composition had the following weight (per 1 m ² ).

Cellulose acetate propionate 2.0g
4-methylphthalic acid 0.7g
Tetrachlorophthalic acid 0.2g
Tetrachlorophthalic anhydride 0.5g
Silica matting agent (average particle size 5μm) 0.5g
1,3-bis (vinylsulfonyl) -2-propanol 50mg
Benzotriazole 30mg
Antistatic agent: F-EO 20mg
Antistatic agent: F-DS1 3mg
[Preparation of non-photosensitive layer coating solution]
While stirring 955 g of methyl ethyl ketone (MEK), 88.7 g of butyral resin was added and sufficiently dissolved by stirring to prepare a non-photosensitive coating solution provided between the photosensitive layer and the support.

[Coating of non-photosensitive layer, photosensitive layer and surface protective layer]
The prepared non-photosensitive layer, photosensitive layer coating solution A, and surface protective layer coating solution were simultaneously coated on the antihalation layer of the prepared support using a known extrusion coater. The coating was carried out so that the non-photosensitive layer was 3.7 μm, the photosensitive layer was coated with a silver amount of 1.5 g / m ² , and the surface protective layer was 2.5 μm in dry film thickness. Thereafter, drying was performed for 10 minutes using a drying air having a drying temperature of 75 ° C. and a dew point temperature of 10 ° C., and a sample 101 was manufactured.

<< Production of photosensitive materials 102 to 119 >>
In the preparation of the photosensitive material 101, instead of the photosensitive silver halide emulsion 1 used in the photosensitive layer, each photosensitive silver halide emulsion prepared according to the following method was changed as shown in Table 3, and Photosensitive materials 102 to 119 were produced in the same manner except that each dye microcapsule prepared according to the following method was added to the non-photosensitive layer in the combination shown in Table 3.

  In addition, in the photosensitive material which added the dye microcapsule to the non-photosensitive layer, it prepared by remove | excluding a dye from the solution a added to the photosensitive layer coating liquid.

The non-photosensitive layer coating solution containing each dye microcapsule was prepared by adding 88.7 g of butyral resin while stirring 955 g of methyl ethyl ketone (MEK), and then dissolving each dye microcapsule in the dissolved solution. Capsule powder was added so that the dye content was 6.0 g / m ^2, and the mixture was sufficiently stirred to prepare each non-photosensitive coating solution.

[Preparation of photosensitive silver halide emulsion]
(Preparation of photosensitive silver halide emulsion 2)
Photosensitive silver halide emulsion 2 was prepared in the same manner as in the preparation of photosensitive silver halide emulsion 1 except that 5 ml of a 0.4% aqueous solution of lead bromide was added to solution D1.

  This emulsion was monodisperse cubic silver iodobromide grains having an average grain size of 0.042 μm, a grain size variation coefficient of 13%, and a [100] face ratio of 94%.

(Preparation of photosensitive silver halide emulsion 3)
In the preparation of the photosensitive silver halide emulsion 1, after addition of the entire amount of the solution F1 after nucleation, 40 ml of a 5% aqueous solution of 4-hydroxy-6-methyl-1,3,3a, 7-tetraazaindene was added. A photosensitive silver halide emulsion 3 was prepared in the same manner as described above.

  This emulsion was monodisperse cubic silver iodobromide grains having an average grain size of 0.041 μm, a grain size variation coefficient of 14%, and a [100] face ratio of 93%.

(Preparation of photosensitive silver halide emulsion 4)
In preparing the above photosensitive silver halide emulsion 1, the same procedure was followed except that 4 ml of a 0.1% ethanol solution of the compound (ETTU) was added after addition of the entire amount of solution F1 after nucleation. 4 was prepared.

  This emulsion was monodisperse cubic silver iodobromide grains having an average grain size of 0.042 μm, a grain size variation coefficient of 10%, and a [100] face ratio of 94%.

(Preparation of photosensitive silver halide emulsion 5)
In the preparation of the above photosensitive silver halide emulsion 1, the same procedure was followed except that 4 ml of a 0.1% ethanol solution of 1,2-benzisothiazolin-3-one was added after addition of the entire amount of solution F1 after nucleation. Photosensitive silver halide emulsion 5 was prepared.

  This emulsion was monodisperse cubic silver iodobromide grains having an average grain size of 0.041 μm, a grain size variation coefficient of 11%, and a [100] face ratio of 93%.

(Preparation of photosensitive silver halide emulsion 6)
In the preparation of the photosensitive silver halide emulsion 1, the temperature before the addition of the solution (G1) was set to 60 ° C., and the total amount of the solution F1 was added after the nucleation. Photosensitive silver halide emulsion 6 was prepared in the same manner except that 4 ml of 1% ethanol solution was added.

  This emulsion was monodisperse cubic silver iodobromide grains having an average grain size of 0.080 μm, a grain size variation coefficient of 12%, and a [100] face ratio of 93%.

(Preparation of photosensitive silver halide emulsion 7)
In the preparation of the photosensitive silver halide emulsion 8, the photosensitive silver halide emulsion 7 was prepared in the same manner except that the compound (ETTU) was not added after adding the whole amount of the solution F1 after nucleation.

  This emulsion was monodisperse cubic silver iodobromide grains having an average grain size of 0.082 μm, a grain size variation coefficient of 14%, and a [100] face ratio of 91%.

[Preparation of dye microcapsules]
(Preparation of dye microcapsule 1)
0.13 g of Exemplified dye compound 1-1 was added to 23.88 g of ethyl acetate with stirring, and it was confirmed that the precipitate disappeared even when the stirring was stopped. Thereafter, 1.01 g of butyral resin (Butbar B-79) was added to completely dissolve the butyral resin.

On the other hand, 1.25 g of gelatin (Miyagi gelatin: 09YR-30) was dissolved in 47.5 g of pure water, and 1.25 g of a 10% solution of a surfactant (Sanyo Kasei: Sanmorin OT-70) was added, followed by dyeing. And an ethyl acetate solution of butyral resin were slowly added, and dispersion was continued for 10 minutes with an ultrasonic disperser to obtain a slightly turbid dispersion. To this, 50 g of a 2.5% aqueous solution of gum arabic is added and stirred for 2 minutes. The obtained dispersion was filtered with a rotary evaporator under reduced pressure until it did not smell of ethyl acetate, and a clear aqueous dispersion was obtained. It was 200 nm when the particle size of the obtained water dispersion was measured. After this, 5% acetic acid is added to the aqueous dispersion,
The pH was adjusted to 3.5 to cause coacervation and microencapsulation. While further stirring well, a reactive compound (glutaraldehyde) for gelatin was added so as to be 10% (solid content) of the whole, and reacted at 50 ° C. for 4 hours. Thereafter, decantation and washing with water were performed three times, and 10 g of colloidal silica (PL-2 manufactured by Fuso Chemical Industry Co., Ltd.) having a salt concentration of 1 ppm or less was added and stirred well, followed by drying with a spray dryer. A powder of microcapsule 1 was obtained.

(Preparation of dye microcapsules 2 to 10)
In the preparation of the dye microcapsule 1, the type of dye, the type of water-soluble resin, the type of reactive compound, the presence or absence of colloidal silica, and the dispersion conditions were changed as shown in Table 2, and the average particle size shown in Table 2 was changed. Powders of dye microcapsules 2 to 10 having a diameter were obtained.

(Preparation of dye microcapsule 11)
0.13 g of Exemplified dye compound 1-1 was added to 23.88 g of ethyl acetate with stirring, and it was confirmed that the precipitate disappeared even when the stirring was stopped. Thereafter, 1.01 g of butyral resin (Butbar B-79) was added to completely dissolve the butyral resin.

  On the other hand, 1.25 g of gelatin (Miyagi gelatin: 09YR-30) was dissolved in 47.5 g of pure water, and further 1.25 g of a 10% solution of a surfactant (Sanyo Kasei: Sanmorin OT-70) was added. And an ethyl acetate solution of butyral resin were slowly added, and dispersion was continued for 10 minutes with an ultrasonic disperser to obtain a slightly turbid dispersion. To this, 50 g of a 2.5% aqueous solution of gum arabic is added and stirred for 2 minutes. The obtained dispersion was filtered under reduced pressure with a rotary evaporator until no ethyl acetate odor was produced, and a clear aqueous dispersion was obtained. The particle size of the obtained aqueous dispersion was measured and found to be 5000 nm. Thereafter, 10 g of colloidal silica (PL-2 manufactured by Fuso Chemical Industry Co., Ltd.) having a salt concentration of 1 ppm or less was added and stirred well, followed by drying with a spray dryer to obtain a powder of dye microcapsule 11. .

<Evaluation of dispersibility of dye microcapsules>
The powder of each dye microcapsule prepared above was dispersed in MEK at a concentration of 1%, and the dispersibility was visually evaluated according to the following criteria. In addition, since the absorption of the dye is shifted to the longer wavelength side in the solid state than the dissolved state, the dye whose absorption is shifted to the longer wavelength side is dispersed and not changed compared to the spectral absorption of the raw material dye. Judged to be dissolved.

5: Dispersed easily by stirring with a magnetic stirrer 4: Dispersed by irradiating ultrasonic waves for 1 minute with an ultrasonic disperser 3: Dispersed by irradiating ultrasonic waves for 3 minutes with an ultrasonic disperser 2: Can be dispersed with an ultrasonic disperser requiring 30 minutes or more of ultrasonic irradiation time 1: Dissolved by stirring with a magnetic stirrer Main composition of each dye microcapsule prepared above, average particle size and The evaluation results of dispersibility are shown in Table 2.

  As can be seen from Table 2, the dispersion of the dye microcapsules of the present invention has good dispersibility.

<< Evaluation of photosensitive material >>
(Exposure and development processing)
From the photosensitive layer coating surface side of each sample produced as described above, exposure by laser scanning is given by an exposure machine using a semiconductor laser having a longitudinal multimode wavelength of 800 to 820 nm by high frequency superposition as an exposure source. It was. At this time, an image was formed by setting the angle of the exposure surface of the sample and the exposure laser beam to 75 degrees. In this method, an image with less unevenness and unexpectedly good sharpness or the like was obtained compared to the case where the angle was 90 degrees.

  Thereafter, using an automatic developing machine having a heat drum, the surface protective layer of the sample and the drum surface were in contact with each other, and heat development was performed at 123 ° C. for 15 seconds. At that time, exposure and development were performed in a room adjusted to 23 ° C. and 50% RH.

(Measurement of sensitivity, fog density and maximum density)
The visual transmission density of the silver image obtained as described above was measured using a transmission densitometer (Densitometer PDA-65 manufactured by Konica Minolta Photo Imaging). The vertical axis represents the image density (D) and the horizontal axis. The characteristic curve which consists of exposure amount (E) was created. In the characteristic curve, the sensitivity is defined as the reciprocal of the logarithm of the exposure amount giving a density 1.0 higher than that of the unexposed area, and the minimum density fog density (minimum density) and the maximum density were measured. Note that the sensitivity and the maximum density are expressed as relative values with each of the samples 101 as 100.

(Evaluation of image storage stability after development)
<Measurement of minimum density change rate (ΔDmin)>
For each of the heat-developed samples prepared by the same method as the sensitivity measurement, a commercially available white fluorescent lamp is placed in an environment of 45 ° C. and 55% RH so that the illuminance on the sample surface is 500 lux for 3 days. Continuous irradiation was applied. The minimum concentration (D2) of the sample irradiated with the fluorescent lamp and the minimum concentration (D1) of the sample not irradiated with the fluorescent lamp were measured, respectively, and the minimum concentration change rate (%) was calculated from the following equation.

Minimum density change rate (ΔDmin) = D2 / D1 × 100 (%)
<Measurement of maximum density change rate (ΔDmax)>
Each heat-developed sample prepared by the same method as the measurement of the minimum density change rate is allowed to stand for 3 days in an environment of 25 ° C. and 45 ° C., and then the maximum density of each sample is measured. The rate of change was measured and used as a measure of image preservation.

Maximum concentration change rate (ΔDmax) = maximum concentration of sample stored at 45 ° C./maximum concentration of sample stored at 25 ° C. × 100 (%)
The results obtained as described above are shown in Table 3.

  As is apparent from Table 3, the silver salt photothermographic dry imaging material of the present invention containing dye microcapsules in the non-photosensitive layer has a reduced fog (minimum density) and the same sensitivity and maximum density compared to the comparative example. It can be seen that the image storability after the development processing is excellent.

Further, as a result of the color tone evaluation of the photosensitive material of the present invention according to the above-described method, the linear regression line determination coefficient (multiple determination) R ² is 0.998 or more and 1.000 or less, and the vertical direction of the linear regression line is Check that the b ^* value at the intersection with the axis is -5 or more and 5 or less and the slope (b ^* / a ^* ) is 0.7 or more and 2.5 or less, and that the color tone is good. I was able to.

Example 2
<< Preparation of photosensitive materials 201-207 >>
In the production of the photosensitive materials 101 to 107 described in Example 1, the same procedure was performed except that the silver halide emulsion used for preparing the photosensitive layer coating solution was chemically sensitized according to the following method. 201-207 were produced.

(Preparation of photosensitive layer coating solution)
In an inert gas atmosphere (nitrogen 97%), the photosensitive emulsion dispersion (50 g) described in Example 1 and 15.11 g of MEK were kept at 21 ° C. with stirring to prevent fogging 1 (10% methanol solution). 390 μl was added and stirred for 1 hour. Next, 240 ml of sulfur sensitizer S-5 (0.5% methanol solution) was added and stirred at 21 ° C. for 1 hour for chemical sensitization. Further, 494 μl of calcium bromide (10% methanol solution) was added and stirred for 20 minutes. Subsequently, 167 ml of the stabilizer solution was added and stirred for 10 minutes, and then 1.32 g of the infrared sensitizing dye solution A was added and stirred for 1 hour. Thereafter, the temperature was lowered to 13 ° C. and further stirred for 30 minutes. While keeping the temperature at 13 ° C., 13.31 g of polyvinyl acetal resin as a binder resin was added and stirred for 30 minutes, and then 1.084 g of tetrachlorophthalic acid (9.4 mass% MEK solution) was added and stirred for 15 minutes. . While further stirring, 12.43 g of additive liquid a, 1.6 ml of Desmodur N3300 / Movey aliphatic isocyanate (10% MEK solution), and 4.27 g of additive liquid b were sequentially added and stirred. A photosensitive layer coating solution was prepared.

<< Evaluation of photosensitive material >>
After performing exposure and development according to the method described in Example 1, the sensitivity, fog density and maximum density were measured and the image storage stability after development was evaluated in the same manner as in Example 1. Table 4 shows the obtained results. The relative sensitivity and the relative maximum density shown in Table 4 are expressed as relative values with each of the photosensitive materials 201 as 100.

  As is clear from Table 4, the silver salt photothermographic dry imaging material of the present invention containing dye microcapsules in the non-photosensitive layer even under the condition of chemically sensitizing the silver halide emulsion, It can be seen that the fog (minimum density) is reduced, the sensitivity and the maximum density are equal to or higher, and the image storability after development processing is excellent.

In each of the above light-sensitive materials, the sulfur sensitizer S-5 (0.5% methanol solution) was used after chemical sensitization to the silver halide emulsion after completion of the final stage (hydrolysis) of the silver halide emulsion preparation process. The photosensitive material prepared by adding 240 ml, chemically agitating by stirring at 55 ° C. for 120 minutes, and adding to a separately prepared coating solution containing an aliphatic carboxylic acid silver salt,
As a result of performing the same evaluation as in the above method, it was confirmed that the result was similar to the above.

Further, as a result of the color tone evaluation of the photosensitive material of the present invention according to the above-described method, the linear regression line determination coefficient (multiple determination) R ² is 0.998 or more and 1.000 or less, and the vertical direction of the linear regression line is Check that the b ^* value at the intersection with the axis is -5 or more and 5 or less and the slope (b ^* / a ^* ) is 0.7 or more and 2.5 or less, and that the color tone is good. I was able to.

Example 3
<Production of support>
Using terephthalic acid and ethylene glycol, polyethylene terephthalate having an intrinsic viscosity of IV = 0.66 (measured in phenol / tetrachloroethane = 6/4 (mass ratio) at 25 ° C.) was obtained according to a conventional method. After pelletizing this, it was dried at 130 ° C. for 4 hours, melted at 300 ° C., extruded from a T-type die, and rapidly cooled to produce an unstretched film having a thickness such that the film thickness after heat setting was 175 μm.

This was longitudinally stretched 3.3 times using rolls having different peripheral speeds and then stretched 4.5 times with a tenter. The temperatures at this time were 110 ° C. and 130 ° C., respectively. Thereafter, the film was heat-fixed at 240 ° C. for 20 seconds and relaxed by 4% in the lateral direction at the same temperature. Thereafter, the chuck portion of the tenter was slit and then knurled at both ends and wound up at 4 kg / cm ² to obtain a roll-shaped support having a thickness of 175 μm.

<Corona discharge treatment of support surface>
Using a solid state corona treatment machine 6KVA model manufactured by Pillar, both surfaces of the produced support were treated at 20 m / min at room temperature. From the current and voltage readings at this time, it was found that the support was subjected to a corona discharge treatment of 0.375 kV · A · min / m ² . The treatment frequency at this time was 9.6 kHz, and the gap clearance between the electrode and the dielectric roll was 1.6 mm.

《Preparation of underdrawn support》
[Photosensitive layer side undercoat coating solution]
59 g of pesresin A-520 (30% by mass solution) manufactured by Takamatsu Yushi Co., Ltd.
Polyethylene glycol monononyl phenyl ether (average ethylene oxide number = 8.5) 10% by mass solution 5.4 g
MP-1000 manufactured by Soken Chemical Co., Ltd. (polymer fine particles, average particle size 0.4 μm)
0.91g
935 ml of distilled water
[Back layer side first layer undercoat coating solution]
Styrene-butadiene copolymer latex (solid content 40% by mass, styrene / butadiene mass ratio = 68/32) 158 g
8 mass% aqueous solution of 2,4-dichloro-6-hydroxy-S-triazine sodium salt
20g
10% 1% by weight aqueous solution of sodium laurylbenzenesulfonate
854 ml of distilled water
[Back layer surface side second layer undercoat layer coating solution]
SnO ₂ / SbO (9/1 mass ratio, average particle size 0.038 μm, 17 mass% dispersion)
84g
Gelatin (10 mass% aqueous solution) 89.2g
8.6 g of Metroise TC-5 (2% by mass aqueous solution) manufactured by Shin-Etsu Chemical Co., Ltd.
MP-1000 0.01g manufactured by Soken Chemical Co., Ltd.
10% 1% by weight aqueous solution of sodium dodecylbenzenesulfonate
NaOH (1% by mass) 6 ml
Proxel (ICI) 1ml
805 ml of distilled water
After the corona discharge treatment is applied to each of both surfaces of the prepared support, the wet coating amount of the photosensitive layer side undercoat layer coating solution is 6.6 ml / m with a wire bar on one side (photosensitive layer surface). ² (per side) and dried at 180 ° C. for 5 minutes, and then the back layer surface side first undercoat layer coating solution is applied to the back surface (back surface) with a wire bar at a wet coating amount of 5. It was applied to 7 ml / m ² and dried at 180 ° C. for 5 minutes. Further, the back layer surface side second layer undercoat layer coating solution was applied to the back surface (back surface) with a wire bar at a wet coating amount of 7.7 ml / m ^2. It was applied to m ² and dried at 180 ° C. for 6 minutes to prepare a sublimed support.

<< Preparation of back surface side coating liquid >>
(Preparation of solid fine particle dispersion (a) of base precursor)
1.5 kg of base precursor compound-1 and 225 g of a surfactant (trade name: Demol N, manufactured by Kao Corporation), 937.5 g of diphenyl sulfone, butyl ester of parahydroxybenzoate (trade name: Plating: Ueno Pharmaceutical Co., Ltd.) 15 g and distilled water were added and the total amount was adjusted to 5.0 kg and mixed, and the mixture was dispersed with beads using a horizontal sand mill (UVM-2: manufactured by Imex Corporation). In the dispersion method, the mixed solution was fed to UVM-2 filled with zirconia beads having an average diameter of 0.5 mm by a diaphragm pump, and dispersed in a state where the internal pressure was 50 hPa or more until a desired average particle size was obtained.

  The dispersion was subjected to spectral absorption measurement and dispersed until the ratio of the absorbance at 450 nm to the absorbance at 650 nm (D450 / D650) in the spectral absorption of the dispersion was 2.2 or more. The obtained dispersion was diluted with distilled water so that the concentration of the base precursor was 20% by mass, and filtered for removing dust (filter made of polypropylene having an average pore size of 3 μm) for practical use.

(Preparation of dye solid fine particle dispersion)
6.0 kg of cyanine dye compound-1 and 3.0 kg of sodium p-dodecylbenzenesulfonate, 0.6 kg of surfactant Demol SNB manufactured by Kao Corporation, and antifoaming agent (trade name: Surfynol 104E, Nissin) 0.15 kg of Chemical Co., Ltd. was mixed with distilled water to make a total liquid volume of 60 kg.

  The mixed solution was dispersed with 0.5 mm zirconia beads using a horizontal sand mill (UVM-2: manufactured by Imex Corporation). The dispersion was subjected to spectral absorption measurement and dispersed until the ratio of the absorbance at 650 nm to the absorbance at 750 nm (D650 / D750) in the spectral absorption of the dispersion was 5.0 or more. The obtained dispersion was diluted with distilled water so that the concentration of the cyanine dye was 6% by mass, and subjected to filter filtration (average pore size: 1 μm) for removing dust.

(Preparation of antihalation layer coating solution)
30 g of gelatin, 24.5 g of polyacrylamide, 2.2 g of 1 mol / L caustic, 2.4 g of monodisperse polymethyl methacrylate fine particles (average particle size 8 μm, particle size standard deviation 0.4), benzoisothiazolinone 0.08 g, 35.9 g of the dye solid fine particle dispersion, 74.2 g of the solid fine particle dispersion (a) of the base precursor, 0.6 g of sodium polyethylene sulfonate, 0.21 g of blue dye compound-1, and acrylic acid / ethyl acrylate Polymerization latex (copolymerization ratio 5/95) 8.3 g was mixed, and the whole was made up to 8183 ml with water to prepare an antihalation layer coating solution.

(Preparation of back surface protective layer coating solution)
The container was kept at 40 ° C., gelatin 40 g, liquid paraffin emulsion 1.5 g as liquid paraffin, benzoisothiazolinone 35 mg, 1 mol / L caustic 6.8 g, t-octylphenoxyethoxyethane sulfonate 0.5 g , 0.27 g of sodium polystyrene sulfonate, 37 mg of fluorosurfactant (F-1), 150 mg of fluorosurfactant (F-2), 64 mg of fluorosurfactant (F-3), fluorosurfactant (F-4) 32 mg, acrylic acid / ethyl acrylate copolymer (copolymerization mass ratio 5/95) 6.0 g, N, N-ethylenebis (vinylsulfoneacetamide) 2.0 g were mixed, and 10 liters with water As a back surface protective layer coating solution.

<Preparation of photosensitive layer surface coating solution>
[Preparation of each additive]
(Preparation of silver halide emulsion)
(Preparation of silver halide emulsion 3-1)
A solution containing 3.1 ml of 1% by weight potassium bromide solution in 1421 ml of distilled water, 3.5 ml of 0.5 mol / L sulfuric acid, and 31.7 g of phthalated gelatin was stirred in a stainless steel reaction vessel. While maintaining the liquid temperature at 30 ° C., the solution A diluted with 95.4 ml of distilled water added to 22.22 g of silver nitrate, 15.3 g of potassium bromide and 0.8 g of potassium iodide in a distilled water volume of 97.4 ml. The whole amount of the solution B diluted to 1 was added at a constant flow rate over 45 seconds. Thereafter, 10 ml of a 3.5% by mass aqueous hydrogen peroxide solution was added, and 4 ml of a 0.1% ethanol solution of the compound (ETTU) was further added. Further, a solution C in which distilled water was added to 51.86 g of silver nitrate to be diluted to 317.5 ml, a solution D in which 44.2 g of potassium bromide and 2.2 g of potassium iodide were diluted with distilled water to a volume of 400 ml was added to solution C. Was added at a constant flow rate over 20 minutes, and solution D was added by the controlled double jet method while maintaining pAg at 8.1. The total amount of potassium hexachloroiridium (III) was added 10 minutes after the start of the addition of Solution C and Solution D so that it would be 1 × 10 ⁻⁴ mole per mole of silver. Further, 5 seconds after the completion of the addition of the solution C, an aqueous solution of potassium iron (II) hexacyanide was added in an amount of 3 × 10 ⁻⁴ mol per mol of silver. The pH was adjusted to 3.8 using 0.5 mol / L sulfuric acid, stirring was stopped, and precipitation / desalting / water washing steps were performed. The pH was adjusted to 5.9 with 1 mol / L sodium hydroxide to prepare a silver halide dispersion having a pAg of 8.0.

While maintaining the silver halide dispersion at 38 ° C. with stirring, 5 ml of a methanol solution of 0.34% by mass of 1,2-benzisothiazolin-3-one was added, and after 40 minutes, the sensitizing dye A and the sensitizing dye A were increased. A methanol solution of 1: 1 in the molar ratio of dye B was added 1.2 × 10 ⁻³ mol of sensitizing dyes A and B per mol of silver, and the temperature was raised to 47 ° C. after 1 minute. 20 minutes after the temperature increase, sodium benzenethiosulfonate was added in a methanol solution to 7.6 × 10 ⁻⁵ moles per 1 mole of silver, and 5 minutes later, tellurium sensitizer C was added in a methanol solution at a rate of 2. per mol of silver. 9 × 10 ⁻⁴ mol was added and aged for 91 minutes. 1.3 ml of a 0.8 mass% methanol solution of N, N′-dihydroxy-N ″ -diethylmelamine was added, and after 4 minutes, 5-methyl-2-mercaptobenzimidazole was added in methanol solution at a rate of 4. Halogenation by adding 5.4 × 10 ⁻³ mol of 8 × 10 ⁻³ mol and 1-phenyl-2-heptyl-5-mercapto-1,3,4-triazole to 1 mol of silver with methanol solution Silver emulsion 3-1 was prepared.

  The grains in the prepared silver halide emulsion 3-1 were silver iodobromide grains uniformly containing 3.5 mol% of iodine having an average sphere equivalent diameter of 0.042 μm and a sphere equivalent diameter variation coefficient of 20%. The particle size and the like were determined from an average of 1000 particles using an electron microscope. The [100] face ratio of the particles was determined to be 80% using the Kubelka-Munk method.

(Preparation of silver halide emulsion 3-2)
In the preparation of the silver halide emulsion 3-1, the liquid temperature at the time of grain formation was changed from 30 ° C. to 47 ° C., and the solution B was diluted with 15.9 g of potassium bromide to a volume of 97.4 ml with distilled water. The solution D was changed to diluting 45.8 g of potassium bromide to a volume of 400 ml with distilled water, and the addition time of the solution C was changed to 30 minutes to remove potassium hexacyanoiron (II). Similarly, silver halide emulsion 3-2 was prepared. Precipitation / desalting / washing / dispersion was carried out in the same manner as silver halide emulsion 3-1. Further, the addition amount of a methanol solution of 1: 1 in the molar ratio of the spectral sensitizing dye A and the spectral sensitizing dye B is 7.5 × 10 ⁻ as the total of the spectral sensitizing dye A and the spectral sensitizing dye B per mole of silver. ⁴ mol, the addition amount of tellurium sensitizer C is 1.1 × 10 ⁻⁴ mol per mol of silver, and 1-phenyl-2-heptyl-5-mercapto-1,3,4-triazole is added to 1 mol of silver. In the same manner as silver halide emulsion 3-1, except that the amount was changed to 3.3 × 10 ⁻³ mol, spectral sensitization, chemical sensitization and 5-methyl-2-mercaptobenzimidazole, 1-phenyl-2-heptyl were performed. -5-Mercapto-1,3,4-triazole was added to obtain a silver halide emulsion 3-2. The grains of silver halide emulsion 3-2 were pure silver bromide cubic grains having an average sphere equivalent diameter of 0.080 μm and a sphere equivalent diameter variation coefficient of 20%.

(Preparation of silver halide emulsion 3-3)
A silver halide emulsion 3-3 was prepared in the same manner as in the preparation of the silver halide emulsion 3-1, except that the liquid temperature 30 ° C. during grain formation was changed to 27 ° C. Further, precipitation / desalting / washing / dispersion was carried out in the same manner as silver halide emulsion 3-1. The molar ratio of spectral sensitizing dye A and spectral sensitizing dye B is 1: 1 as a solid dispersion (gelatin aqueous solution), and the addition amount is 6 × 10 ⁻ as the total of sensitizing dye A and sensitizing dye B per mole of silver. ³ mol, the amount of tellurium sensitizer C changed to 1 mole of silver per 5.2 × 10 ^-4 mol, silver bromide aurate after addition thirds of tellurium sensitizer C mole per 5 × 10 ^{- A} silver halide emulsion 3-3 was obtained in the same manner as silver halide emulsion 3-1, except that ⁴ mol and 2 × 10 ⁻³ mol of potassium thiocyanate were added per mol of silver. The grains of the silver halide emulsion 3-3 were silver iodobromide grains uniformly containing 3.5 mol% of iodine having an average sphere equivalent diameter of 0.034 μm and a sphere equivalent diameter variation coefficient of 20%.

(Preparation of silver halide emulsion 3-4)
In the preparation of silver halide emulsion 3-1, silver halide emulsion 3-4 was prepared in the same manner except that the compound (ETTU) was not added at the time of grain formation. The grains in the prepared silver halide emulsion 3-4 were silver iodobromide grains uniformly containing 3.5 mol% of iodine having an average sphere equivalent diameter of 0.044 μm and a sphere equivalent diameter variation coefficient of 19%. It was. The [100] face ratio of the particles was determined to be 82%.

(Preparation of silver halide emulsion 3-5)
A silver halide emulsion 3-5 was prepared in the same manner as in the preparation of the silver halide emulsion 3-2 except that the compound (ETTU) was not added during grain formation. The grains of the silver halide emulsion 3-5 were pure silver bromide cubic grains having an average sphere equivalent diameter of 0.081 μm and a sphere equivalent diameter variation coefficient of 17%.

(Preparation of silver halide emulsion 3-6)
A silver halide emulsion 3-6 was prepared in the same manner as in the preparation of the silver halide emulsion 3-3 except that the compound (ETTU) was not added during grain formation. The grains of silver halide emulsion 3-6 were silver iodobromide grains uniformly containing 3.5 mol% of iodine having an average sphere equivalent diameter of 0.032 μm and a sphere equivalent diameter variation coefficient of 18%.

[Preparation of mixed emulsion for photosensitive layer]
(Preparation of mixed emulsion A for photosensitive layer)
70% by mass of silver halide emulsion 3-1, 15% by mass of silver halide emulsion 3-2 and 15% by mass of silver halide emulsion 3-3 are dissolved, and 1% by mass of benzothiazolium iodide. 7 × 10 ⁻³ mol per mol of silver was added in an aqueous solution. Further, the mixed emulsion A for photosensitive layer was prepared by adding water so that the content of silver halide per 1 kg of the above mixed emulsion for photosensitive layer was 38.2 g as silver.

(Preparation of mixed emulsion B for photosensitive layer)
70% by weight of silver halide emulsion 3-4, 15% by weight of silver halide emulsion 3-5 and 15% by weight of silver halide emulsion 3-6 are dissolved, and 1% by weight of benzothiazolium iodide. 7 × 10 ⁻³ mol per mol of silver was added in an aqueous solution. Further, the mixed emulsion B for photosensitive layer was prepared by adding water so that the content of silver halide per 1 kg of the above mixed emulsion for photosensitive layer was 38.2 g as silver.

(Preparation of silver behenate dispersion)
100 kg of Henkel behenic acid (product name Edenor C22-85R) was mixed in 1200 kg of isopropyl alcohol, dissolved at 50 ° C., filtered through a 10 μm filter, cooled to 30 ° C., and recrystallized. The cooling speed during recrystallization was controlled at 3 ° C./hour. The obtained crystals were centrifugally filtered, washed with 100 kg of isopropyl alcohol, and then dried. When the obtained crystals were esterified and subjected to GC-FID measurement, the silver behenate content was 99%, and in addition, 0.5% lignoceric acid and 0.5% arachidic acid were contained.

  Next, 88 kg of the above recrystallized behenic acid, 422 L of distilled water, 49.2 L of NaOH aqueous solution having a concentration of 5 mol / L, and 120 L of t-butyl alcohol are mixed and stirred at 75 ° C. for 1 hour to react to obtain a sodium behenate solution. It was. Separately, 206.2 L (pH 4.0) of an aqueous solution containing 40.4 kg of silver nitrate was prepared and kept warm at 10 ° C. A reaction vessel containing 635 L of distilled water and 30 L of t-butyl alcohol was kept at 30 ° C., and with sufficient agitation, the total amount of the previous sodium behenate solution and the total amount of silver nitrate aqueous solution were kept at a constant flow rate of 93 minutes and 15 seconds, respectively. And added over 90 minutes. At this time, only the silver nitrate aqueous solution is added for 11 minutes after the start of the addition of the silver nitrate aqueous solution, and then the addition of the sodium behenate solution B is started. After the addition of the silver nitrate aqueous solution, only the sodium behenate solution B is added for 14 minutes and 15 seconds Was added. At this time, the temperature in the reaction vessel was 30 ° C., and the external temperature was controlled so that the liquid temperature was constant. The pipe of the addition system for the sodium behenate solution was kept warm by circulating hot water outside the double pipe so that the liquid temperature at the outlet at the tip of the addition nozzle was 75 ° C. Moreover, the piping of the addition system of the silver nitrate aqueous solution was kept warm by circulating cold water outside the double pipe. The addition position of the sodium behenate solution and the addition position of the aqueous silver nitrate solution were arranged symmetrically around the stirring axis, and were adjusted so as not to contact the reaction solution.

  After completion of the addition of the sodium behenate solution, the mixture was left stirring for 20 minutes at the same temperature, heated to 35 ° C. over 30 minutes, and then aged for 210 minutes. Immediately after completion of the aging, the solid content was separated by centrifugal filtration, and the solid content was washed with water until the conductivity of the filtrate water reached 30 μS / cm. Thus, a fatty acid silver salt was obtained. The obtained solid content was stored as a wet cake without drying.

  When the morphology of the obtained silver behenate particles was evaluated by electron microscope photography, it was a crystal having an average aspect ratio of 2.1, an average sphere equivalent diameter of 0.51 μm, and a sphere equivalent diameter variation coefficient of 11%.

  19.3 kg of polyvinyl alcohol (trade name: PVA-217) and water are added to a wet cake corresponding to a dry solid content of 260 kg. Co., Ltd .: PM-10 type).

Next, the pre-dispersed stock solution was subjected to a pressure of 1.13 × 10 ⁵ kPa (1150 kg / cm) using a disperser (trade name: Microfluidizer M-610, manufactured by Microfluidics International Corporation, using a Z-type interaction chamber). ^The mixture was adjusted to ² ) and processed three times to obtain a silver behenate dispersion. The cooling operation was carried out by installing a serpentine heat exchanger before and after the interaction chamber, and adjusting the temperature of the refrigerant to a dispersion temperature of 18 ° C.

(Preparation of reducing agent dispersion)
(Preparation of reducing agent-1 dispersion)
10 kg of 1: 1 complex of reducing agent-1 (6,6'-di-t-butyl-4,4'-dimethyl-2,2'-butylidenediphenol) and triphenylphosphine oxide; 10 kg of water was added to 12 kg and 16 kg of a 10 wt% aqueous solution of modified polyvinyl alcohol (Kuraray Co., Ltd., Poval MP203) and mixed well to obtain a slurry. This slurry was fed with a diaphragm pump and dispersed for 4 hours 30 minutes in a horizontal sand mill (UVM-2: manufactured by Imex Co., Ltd.) filled with zirconia beads having an average diameter of 0.5 mm, and then benzoisothiazolinone sodium salt 0.2 g and water were added to prepare a reducing agent complex concentration of 22% by mass to obtain a reducing agent-1 dispersion. The reducing agent complex particles contained in the thus obtained reducing agent-1 dispersion had a median diameter of 0.45 μm and a maximum particle diameter of 1.4 μm or less. The obtained reducing agent-1 dispersion was filtered through a polypropylene filter having a pore size of 3.0 μm to remove foreign substances such as dust and stored.

(Preparation of reducing agent-2 dispersion)
10 mass of reducing agent-2 (6,6'-di-t-butyl-4,4'-dimethyl-2,2'-butylidene diphenol) and modified polyvinyl alcohol (Kuraray Co., Ltd., Poval MP203) 10 kg of water was added to 16 kg of% aqueous solution and mixed well to obtain a slurry. This slurry was fed with a diaphragm pump, dispersed in a horizontal sand mill (UVM-2: manufactured by Imex Co., Ltd.) filled with zirconia beads having an average diameter of 0.5 mm for 3 hours 30 minutes, and then benzoisothiazolinone sodium salt 0.2 g and water were added to prepare a reducing agent concentration of 25% by mass to obtain a reducing agent-2 dispersion. The reducing agent particles contained in the thus obtained reducing agent-2 dispersion had a median diameter of 0.40 μm and a maximum particle diameter of 1.5 μm or less. The obtained reducing agent-2 dispersion was filtered through a polypropylene filter having a pore size of 3.0 μm to remove foreign substances such as dust and stored.

(Preparation of hydrogen bonding compound-1 dispersion)
Add 10 kg of water to 10 kg of 10% aqueous solution of hydrogen bonding compound-1 (tri (4-t-butylphenyl) phosphine oxide) and modified polyvinyl alcohol (Kuraray Co., Ltd., Poval MP203). Mix to make a slurry. This slurry was fed with a diaphragm pump and dispersed for 3 hours 30 minutes in a horizontal sand mill (UVM-2: manufactured by Imex Co., Ltd.) filled with zirconia beads having an average diameter of 0.5 mm, and then benzoisothiazolinone sodium salt 0.2 g and water were added to prepare a hydrogen bonding compound concentration of 25% by mass to obtain a hydrogen bonding compound-1 dispersion. The hydrogen bonding compound particles contained in the hydrogen bonding compound-1 dispersion thus obtained had a median diameter of 0.35 μm and a maximum particle diameter of 1.5 μm or less. The obtained hydrogen bonding compound-1 dispersion was filtered through a polypropylene filter having a pore size of 3.0 μm to remove foreign substances such as dust and stored.

(Preparation of Development Accelerator-1 Dispersion)
10 kg of development accelerator-1 and 20 kg of 10% by weight aqueous solution of modified polyvinyl alcohol (Kuraray Co., Ltd., Poval MP203) were added to 10 kg of water and mixed well to obtain a slurry. This slurry was fed with a diaphragm pump and dispersed for 3 hours 30 minutes in a horizontal sand mill (UVM-2: manufactured by Imex Co., Ltd.) filled with zirconia beads having an average diameter of 0.5 mm, and then benzoisothiazolinone sodium salt 0.2 g and water were added to adjust the concentration of the development accelerator to 20% by mass to obtain a development accelerator-1 dispersion. The development accelerator particles contained in the thus obtained development accelerator-1 dispersion had a median diameter of 0.48 μm and a maximum particle diameter of 1.4 μm or less. The obtained development accelerator-1 dispersion was filtered through a polypropylene filter having a pore size of 3.0 μm to remove foreign substances such as dust, and stored.

(Preparation of Development Accelerator-2, 3 Dispersion and Color Adjuster-1 Dispersion)
In the same manner as in the preparation of the above development accelerator-1 dispersion, the development accelerator-2 dispersion, the development accelerator-3 dispersion are prepared using the development accelerator-2, the development accelerator-3, and the color tone adjusting agent-1. And a 20% by weight dispersion of the color tone modifier-1 dispersion were obtained.

[Preparation of polyhalogen compound]
(Preparation of organic polyhalogen compound-1 dispersion)
10 kg of organic polyhalogen compound-1 (tribromomethanesulfonylbenzene), 10 kg of a 20% by weight aqueous solution of modified polyvinyl alcohol (Poval MP203 manufactured by Kuraray Co., Ltd.), 0.4 kg of a 20% by weight aqueous solution of sodium triisopropylnaphthalenesulfonate, Then, 14 kg of water was added and mixed well to obtain a slurry. This slurry was fed with a diaphragm pump and dispersed for 5 hours in a horizontal sand mill (UVM-2: manufactured by Imex Co., Ltd.) filled with zirconia beads having an average diameter of 0.5 mm. 2 g and water were added to prepare an organic polyhalogen compound concentration of 26% by mass to obtain an organic polyhalogen compound-1 dispersion. The organic polyhalogen compound particles contained in the thus obtained polyhalogen compound-1 dispersion had a median diameter of 0.41 μm and a maximum particle diameter of 2.0 μm or less. The obtained organic polyhalogen compound-1 dispersion was filtered through a polypropylene filter having a pore size of 10.0 μm to remove foreign substances such as dust and stored.

(Preparation of organic polyhalogen compound-2 dispersion)
10 kg of an organic polyhalogen compound-2 (N-butyl-3-tribromomethanesulfonylbenzoamide), 20 kg of a 10% by weight aqueous solution of modified polyvinyl alcohol (Poval MP203 manufactured by Kuraray Co., Ltd.), and 20 of sodium triisopropylnaphthalenesulfonate 0.4 kg of a mass% aqueous solution was added and mixed well to obtain a slurry. This slurry was fed with a diaphragm pump and dispersed for 5 hours in a horizontal sand mill (UVM-2: manufactured by Imex Co., Ltd.) filled with zirconia beads having an average diameter of 0.5 mm. 2 g and water were added to prepare an organic polyhalogen compound concentration of 30% by mass. This dispersion was heated at 40 ° C. for 5 hours to obtain an organic polyhalogen compound-2 dispersion. The organic polyhalogen compound particles contained in the thus obtained polyhalogen compound-2 dispersion had a median diameter of 0.40 μm and a maximum particle diameter of 1.3 μm or less. The obtained organic polyhalogen compound-2 dispersion was filtered through a polypropylene filter having a pore size of 3.0 μm to remove foreign substances such as dust and stored.

(Preparation of phthalazine compound-1 solution)
8 kg of modified polyvinyl alcohol MP203 manufactured by Kuraray Co., Ltd. was dissolved in 174.57 kg of water, then 3.15 kg of a 20% by weight aqueous solution of sodium triisopropylnaphthalenesulfonate and 70 of phthalazine compound-1 (6-isopropylphthalazine). 14.28 kg of a mass% aqueous solution was added to prepare a 5 mass% solution of phthalazine compound-1.

(Preparation of mercapto compound)
(Preparation of mercapto compound-1 aqueous solution)
7 g of mercapto compound-1 [1- (3-sulfophenyl) -5-mercaptotetrazole sodium salt] was dissolved in 993 g of water to obtain a 0.7 mass% mercapto compound-1 aqueous solution.

(Preparation of mercapto compound-2 aqueous solution)
20 g of mercapto compound-2 [1- (3-methylureido) -5-mercaptotetrazole sodium salt] was dissolved in 980 g of water to obtain a 2.0 mass% mercapto compound-2 aqueous solution.

[Preparation of Pigment-1 Dispersion]
C. I. 250 g of water was added to 64 g of Pigment Blue 60 and 6.4 g of DEMOL N manufactured by Kao Co., Ltd., and mixed well to prepare a slurry. Prepare 800 g of zirconia beads having an average diameter of 0.5 mm, put them in a vessel together with the slurry, and disperse with a disperser (1/4 G sand grinder mill: manufactured by IMEX Co., Ltd.) for 25 hours. Obtained. The pigment particles contained in the pigment-1 dispersion thus obtained had an average particle size of 0.21 μm.

[Preparation of SBR latex solution]
An SBR latex having a Tg of 22 ° C. was prepared as follows.

Ammonium persulfate is used as a polymerization initiator, an anionic surfactant is used as an emulsifier, 70.0 mass of styrene, 27.0 mass of butadiene and 3.0 mass of acrylic acid are emulsion-polymerized, and then aging is performed at 80 ° C. for 8 hours. It was. Thereafter, the mixture was cooled to 40 ° C., adjusted to pH 7.0 with aqueous ammonia, and Sandet BL manufactured by Sanyo Chemical Co., Ltd. was further added to 0.22%. Next, 5% aqueous sodium hydroxide solution was added to adjust the pH to 8.3, and further adjusted to pH 8.4 with aqueous ammonia. The molar ratio of Na ⁺ ions and NH ₄ ⁺ ions used at this time was 1: 2.3. Further, 0.15 ml of a 7% aqueous solution of benzoisothiazoline non sodium salt was added to 1 kg of this liquid to prepare an SBR latex liquid.

  The SBR latex is a latex of -St (70.0) -Bu (27.0) -AA (3.0)-, Tg 22 ° C., average particle size 0.1 μm, concentration 43% by mass, 25 ° C. 60% RH. Equilibrium water content of 0.6% by mass, ion conductivity of 4.2 mS / cm (Ion conductivity was measured using a conductivity meter CM-30S manufactured by Toa Denpa Kogyo Co., Ltd.), and latex stock solution (43% by mass) was 25 PH measured at ℃), pH 8.4.

[Preparation of photosensitive layer 1 coating solution]
1000 g of the fatty acid silver dispersion obtained above, 276 ml of water, 33.2 g of pigment-1 dispersion, 21 g of organic polyhalogen compound-1 dispersion, 58 g of organic polyhalogen compound-2 dispersion, 173 g of phthalazine compound-1 solution, SBR 1082 g of latex (Tg: 22 ° C.) liquid, 299 g of reducing agent complex-1 dispersion, 6 g of development accelerator-1 dispersion, 9 ml of mercapto compound-1 aqueous solution, and 27 ml of mercapto compound-2 aqueous solution were sequentially added. 117 g of silver halide mixed emulsion A was added and mixed well to prepare photosensitive layer 1 coating solution.

[Preparation of photosensitive layer 2 coating solution]
1000 g of the fatty acid silver dispersion obtained above, 276 ml of water, 32.8 g of pigment-1 dispersion, 21 g of organic polyhalogen compound-1 dispersion, 58 g of organic polyhalogen compound-2 dispersion, 173 g of phthalazine compound-1 solution, SBR 1082 g of latex (Tg: 20 ° C.) liquid, 155 g of reducing agent-2 dispersion, 55 g of hydrogen bonding compound-1 dispersion, 6 g of development accelerator-1 dispersion, 2 g of development accelerator-2 dispersion, development accelerator- 3 g of 3 dispersion, 2 g of color adjusting agent-1 dispersion, and 6 ml of mercapto compound-2 aqueous solution were added in order, and 117 g of silver halide mixed emulsion A was added just before coating and mixed well to prepare photosensitive layer 2 coating solution. did.

[Preparation of intermediate layer coating solution]
1000 g of polyvinyl alcohol PVA-205 (manufactured by Kuraray Co., Ltd.), 272 g of 5% by weight dispersion of pigment-1, methyl methacrylate / styrene / butyl acrylate / hydroxyethyl methacrylate / acrylic acid copolymer (copolymer mass ratio 64/9) / 20/5/2) 27% of 5% aqueous solution of aerosol OT (manufactured by American Cyanamid Co., Ltd.) in 4200 ml of 19% by weight latex, 135 ml of 20% by weight aqueous solution of diammonium phthalate, totaling 10,000 g Water was added as described above, and the intermediate layer coating solution was prepared by adjusting with NaOH so that the pH was 7.5, and the solution was fed to the coating die so as to be 9.1 ml / m ² . The viscosity of the coating solution was 58 (mPa · s) at 40 ° C. (No. 1 rotor, 60 rpm) with a B-type viscometer.

[Preparation of coating solution for protective layer first layer]
Inert gelatin (64 g) is dissolved in water, and methyl methacrylate / styrene / butyl acrylate / hydroxyethyl methacrylate / acrylic acid copolymer (copolymerization mass ratio 64/9/20/5/2) 27.5% by weight latex 80 g, 23 ml of a 10% by weight methanol solution of phthalic acid, 23 ml of a 10% by weight aqueous solution of 4-methylphthalic acid, 28 ml of sulfuric acid having a concentration of 0.5 mol / L, and a 5% by weight aqueous solution of Aerosol OT (American Cyanamid Co., Ltd.) Add 5 ml, 0.5 g phenoxyethanol, 0.1 g benzoisothiazolinone, add water to make a total amount of 750 g, and use 26 ml of 4% by weight chromium alum mixed with a static mixer just before coating. The solution was fed to the coating die so as to be 18.6 ml / m ² . The viscosity of the coating solution was 20 (mPa · s) at a B-type viscometer of 40 ° C. (No. 1 rotor, 60 rpm).

[Preparation of coating solution for surface protective layer second layer]
80 g of inert gelatin is dissolved in water, and a methyl methacrylate / styrene / butyl acrylate / hydroxyethyl methacrylate / acrylic acid copolymer (copolymerization mass ratio 64/9/20/5/2) latex 27.5% by mass solution 102 g, 3.2 ml of a 5% by mass solution of a fluorosurfactant (F-1: N-perfluorooctylsulfonyl-N-propylalanine potassium salt), a fluorosurfactant (F-2: polyethylene glycol mono (N- Perfluorooctylsulfonyl-N-propyl-2-aminoethyl) ether [ethylene oxide average polymerization degree = 15]) 2 mass% aqueous solution 32 ml, aerosol OT (manufactured by American Cyanamid Co., Ltd.) 5 mass% solution 23 ml , 4 g of polymethyl methacrylate fine particles (average particle size 0.7 μm), Water so that the total amount is 650 g in 21 g of dimethyl methacrylate fine particles (average particle size: 4.5 μm), 1.6 g of 4-methylphthalic acid, 4.8 g of phthalic acid, 44 ml of 0.5 mol / L sulfuric acid, and 10 mg of benzoisothiazolinone. Was added with 445 ml of an aqueous solution containing 4% by weight of chrome alum and 0.67% by weight of phthalic acid using a static mixer immediately before coating to obtain a surface protective layer second layer coating solution, 8.3 ml The solution was fed to the coating die so as to be / m ² . The viscosity of the coating solution was 19 (mPa · s) at 40 ° C. (No. 1 rotor, 60 rpm) B-type viscometer.

<< Production of Photosensitive Material 301 >>
On the back surface side of the undercoat support, the antihalation layer coating solution is applied so that the solid content coating amount of the solid fine particle dye is 0.04 g / m ^2, and the back surface protective layer coating solution is prepared with a gelatin coating amount of A simultaneous multilayer coating was applied so as to be 0.7 g / m ² , followed by drying to form a back layer surface side.

  On the surface opposite to the back surface side, the photosensitive layer 301 is coated simultaneously by the slide bead coating method in the order of the photosensitive layer 1, the intermediate layer, the protective layer first layer, and the surface protective layer second layer from the undercoat surface. Was made. At this time, the photosensitive layer and the intermediate layer were adjusted to 31 ° C., the protective layer first layer was adjusted to 36 ° C., and the surface protective layer second layer was adjusted to 37 ° C.

The coating amount (g / m ² ) of each compound of the photosensitive layer 1 used for the production is as follows.

  Silver behenate: 5.55, pigment (CI Pigment Blue 60): 0.036, organic polyhalogen compound-1: 0.12, organic polyhalogen compound-2: 0.37, phthalazine compound-1: 0.19, SBR latex: 9.67, reducing agent-2: 0.81, hydrogen bonding compound-1: 0.30, development accelerator-1: 0.024, development accelerator-2: 0.010 , Development accelerator-3: 0.015, color tone adjuster-1: 0.010, mercapto compound-2: 0.002 silver halide (as Ag): 0.091.

  The application and drying conditions in the production of the photosensitive material 301 are as follows. The coating was performed at a speed of 160 m / min, the gap between the coating die tip and the support was set to 0.10 to 0.30 mm, and the pressure in the decompression chamber was set to be 196 to 882 Pa lower than the atmospheric pressure. The support was neutralized with an ion wind before coating. In the subsequent chilling zone, after cooling the coating solution with wind at a dry bulb temperature of 10 to 20 ° C., the coating solution is transported in a non-contact manner, and dried at a dry bulb temperature of 23 to 45 ° C. It dried with the dry wind of the wet bulb temperature 15-21 degreeC. After drying, the humidity was adjusted at 25 ° C. and humidity of 40 to 60% RH, and then the film surface was heated to 70 to 90 ° C. After heating, the film surface was cooled to 25 ° C.

<< Production of Photosensitive Material 302 >>
A photosensitive material 302 was prepared in the same manner as in the preparation of the photosensitive material 301 except that the photosensitive layer 2 coating solution was used instead of the photosensitive layer 1 coating solution.

<< Production of photosensitive materials 303 and 304 >>
In the preparation of the photosensitive materials 301 and 302, the basic precursor solid fine particle dispersion and the dye solid fine particle dispersion were removed from the antihalation layer coating solution, and the photosensitive layer and the support were further treated in the same manner as described in Example 1. Photosensitive materials 303 and 304 were prepared in the same manner except that a non-photosensitive layer containing the dye microcapsule 1 prepared in Example 1 was provided between the bodies with a dry film thickness of 3.7 μm.

<< Evaluation of photosensitive material >>
(Exposure and development processing)
Each sample prepared as described above was exposed and thermally developed (112 ° C / 119 ° C / 121 ° C / 121 ° C) using a medical dry laser imager (mounted with a 660 nm semiconductor laser with a maximum output of 60 mW (IIIB)). For a total of 14 seconds).

(Measurement of each characteristic value)
Similar to the method described in Example 1, the sensitivity, fog density and maximum density were measured, the image storage stability after development was evaluated, and the stain and odor of the heat developing drum were evaluated according to the following method. The results are shown in Table 5. The relative sensitivity and the relative maximum density shown in Table 5 are expressed as relative values with each of the photosensitive materials 301 as 100.

<Evaluation of stain resistance and odor resistance of heat developing drum>
After the above heat development processing is continuously performed for 1 hour, the odor of the heat development environment is confirmed, and the surface of the heat development drum in the imager is visually observed. Evaluation was performed.

○: No odor is felt even after continuous heat development, and no foreign matter is adhered to the heat development and ram surface. ×: Offensive odor is felt by continuous heat development, and heat development and ram surface. Foreign matter is also observed in

  As is apparent from Table 5, the silver salt photothermographic dry imaging material of the present invention containing dye microcapsules in the non-photosensitive layer has a reduced fog (minimum density) and the same sensitivity and maximum density compared to the comparative example. As described above, the image storage property after the development processing is excellent, and it is understood that the stain resistance and the odor resistance of the heat developing drum of the imager are improved.

Further, as a result of the color tone evaluation of the photosensitive material of the present invention according to the above-described method, the linear regression line determination coefficient (multiple determination) R ² is 0.998 or more and 1.000 or less, and the vertical direction of the linear regression line is Check that the b ^* value at the intersection with the axis is -5 or more and 5 or less and the slope (b ^* / a ^* ) is 0.7 or more and 2.5 or less, and that the color tone is good. I was able to.

Claims (11)

A silver salt photothermographic dry imaging material comprising a non-photosensitive aliphatic carboxylic acid silver salt particle, a photosensitive silver halide particle, a silver ion reducing agent, a binder and a dye microcapsule dispersion, wherein the photosensitive silver halide The silver halide grains in which the grains are converted from the surface latent image type to the internal latent image type in the thermal development process and the surface sensitivity is lower than before the thermal development process, and the dye microcapsule dispersion is in accordance with the following method A silver salt photothermographic dry imaging material, which is a prepared dye microcapsule dispersion A.
<Dye microcapsule dispersion A>
After a composition in which a dye and a binder are dissolved in a volatile organic solvent capable of dissolving the dye and the binder is dispersed in an aqueous solution of a water-soluble resin, the volatile organic solvent is evaporated to form a wall film (shell). After forming a microcapsule containing a dye, water is evaporated and dried, and then the microcapsule dispersion is dispersed in an organic solvent A silver salt photothermographic dry imaging material comprising a non-photosensitive aliphatic carboxylic acid silver salt particle, a photosensitive silver halide particle, a silver ion reducing agent, a binder and a dye microcapsule dispersion, wherein the photosensitive silver halide The silver halide grains in which the grains are converted from the surface latent image type to the internal latent image type in the thermal development process and the surface sensitivity is lower than before the thermal development process, and the dye microcapsule dispersion is in accordance with the following method A silver salt photothermographic dry imaging material, which is a prepared dye microcapsule dispersion B.
<Dye microcapsule dispersion B>
After a composition in which a dye and a binder are dissolved in a volatile organic solvent capable of dissolving the dye and the binder is dispersed in an aqueous solution of a water-soluble resin, the volatile organic solvent is evaporated to form a wall film (shell). After forming a microcapsule containing a dye, colloidal silica is added, water is evaporated and dried, and then the microcapsule dispersion is dispersed in an organic solvent A silver salt photothermographic dry imaging material comprising a non-photosensitive aliphatic carboxylic acid silver salt particle, a photosensitive silver halide particle, a silver ion reducing agent, a binder and a dye microcapsule dispersion, wherein the photosensitive silver halide The silver halide grains in which the grains are converted from the surface latent image type to the internal latent image type in the thermal development process and the surface sensitivity is lower than before the thermal development process, and the dye microcapsule dispersion is in accordance with the following method A silver salt photothermographic dry imaging material, wherein the dye microcapsule dispersion C is prepared.
<Dye microcapsule dispersion C>
After a composition in which a dye and a binder are dissolved in a volatile organic solvent capable of dissolving the dye and the binder is dispersed in an aqueous solution of a water-soluble resin, the volatile organic solvent is evaporated to form a wall film (shell). Disperse dye microcapsules by forming a microcapsule containing a dye, adding a compound that reacts with the hydrophilic group of the water-soluble resin, evaporating and drying water, and then dispersing the microcapsule in an organic solvent Stuff The silver salt photothermographic dry imaging material according to any one of claims 1 to 3, wherein the water-soluble resin used for preparing the dye microcapsule dispersion is gelatin or gum arabic. Expose white light or light in a specific spectral sensitization region through an optical wedge for a fixed exposure time, and heat develop under normal practical heat development conditions, then set the sensitivity obtained based on the characteristic curve to S ₁ Heat treatment is performed under the same conditions as the practical heat development conditions before, and then white light or light in a specific spectral sensitization region is exposed through an optical wedge for a fixed exposure time, and further heat development is performed under the practical heat development conditions. after, when the sensitivity obtained on the basis of the characteristic curve was S _2, silver salt photothermal according to any one of claims 1 to 4, S ₂ / S ₁ is equal to or more than 0.1 Photo dry imaging material. The silver salt photothermographic image according to any one of claims 1 to 5, wherein the photosensitive silver halide grains contain a dopant that functions as an electron trap at least after thermal development in the grains. Dry imaging material. The surface of the photosensitive silver halide grain is spectrally sensitized by adsorbing a spectral sensitizing dye, and the effect of the spectral sensitization substantially disappears after the thermal development process. The silver salt photothermographic dry imaging material according to any one of claims 1 to 6. The surface of the photosensitive silver halide grain is chemically sensitized, and the effect of the chemical sensitization substantially disappears after the thermal development process. 2. A silver salt photothermographic dry imaging material according to item 1. The surface of the photosensitive silver halide grains is subjected to spectral sensitization by adsorbing chemical sensitization and spectral sensitizing dyes, and the effects of the chemical sensitization and spectral sensitization after the thermal development process are substantially realized. The silver salt photothermographic dry imaging material according to any one of claims 1 to 6, wherein the material disappears automatically. A laser beam scanning exposure apparatus, wherein the silver salt photothermographic dry imaging material according to any one of claims 1 to 9 is exposed to light to record an image, wherein the scanning laser beam is a vertical multi-beam. An image recording method comprising: A method for forming an image by subjecting the silver salt photothermographic dry imaging material according to any one of claims 1 to 9 to heat development, wherein the heat development is performed using the silver salt photothermographic dry imaging material. Is carried out in a state containing 40 to 4500 ppm of an organic solvent.