JP2006003699A - Silver salt photothermal photographic imaging material and image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a silver salt photographic imaging material which is extremely stable in the cold black tone in silver color tone and the sensitivity and maximum density of the output image with respect to a fluctuation in the oscillation wavelength in exposure with a laser scanning exposure machine and hardly deteriorates the color, density, fogging and density of the image, and to provide an image recording method using the silver salt photographic imaging material. <P>SOLUTION: In the silver salt photographic imaging material having an image forming layer containing a non-photosensitive organic silver salt, silver halide, silver ion reducing agent, and a binder, at least one kind of the silver ion reducing agent is a compound (α) expressed by general formula (1) and contains a yellow chromophoric leuco dye (β) and cyan chromophoric leuco dye (γ) on the surface side having the image forming layer, and the ratio of amounts of addition of (β) and (α) (the number of moles (β)/the number of moles (α)) is 0.01 to 0.2 and ratio of the amounts of addition of (γ) and (α) (the number of moles (γ)/the number of moles (α)) is 0.01 to 0.5. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a silver salt photothermographic imaging material and an image recording method using the imaging material.

  In recent years, in the field of medical and printing plate making, there has been a need for techniques relating to photothermographic materials that can be used for efficient exposure, such as laser imagers and laser imagesetters, and that can form clear black images with high resolution. Has been.

  Thermal imaging systems using organic silver salts as such techniques are described, for example, in U.S. Pat. Nos. 3,152,904 and 3,457,075 and D.C. Klosterboer, “Thermally Processed Silver Systems” (Imaging Processes and Materials), 8th edition, J. Sturge. (Walworth, A. Shepp, Chapter 9, 279, 1989). In particular, silver salt photothermographic dry imaging materials generally control a catalytically active amount of a photocatalyst (eg, silver halide), a reducing agent, a reducible silver salt (eg, an organic silver salt), and optionally control the color of silver. It has a photosensitive layer in which a toning agent is dispersed in a binder matrix. The silver salt photothermographic dry imaging material is heated to a high temperature (for example, 80 ° C. or more) after image exposure, and a black-and-white film is formed by a redox reaction between a reducible silver salt (functioning as an oxidizing agent) and a reducing agent Form a silver image. The oxidation-reduction reaction is promoted by the catalytic action of the latent image of silver halide generated by exposure. Therefore, a black silver image is formed in the exposure area. It is disclosed in many documents including US Pat. No. 2,910,377 and Japanese Patent Publication No. 43-4924.

Silver salt photothermographic dry imaging materials have come to be frequently used especially for medical diagnostic applications because of their convenience. Medical diagnostic images are required to have fine picture quality, and therefore require high image quality with excellent sharpness and graininess. In addition, cold-black images are preferred from the viewpoint of ease of diagnosis. Although it is difficult to produce a pure black color tone with this photothermal image forming system using organic silver salt, the color tone is adjusted with the above-mentioned colorant or the like, but the color tone control is not sufficient, and improvement is desired. Although a combination of a specific reducing agent and a specific compound has been disclosed as a technique for improving this defect (see Patent Documents 1 and 2), the improvement effect is not sufficient, and the color and density of an image during storage are not satisfactory. In addition, the fog is increased and the sensitivity is decreased. In addition, when exposed using a laser scanning exposure machine, the density of the output image tends to fluctuate due to slight fluctuations in oscillation wavelength and temperature. However, it has serious problems and further improvement has been demanded.
JP 2002-169249 A JP 2002-236334 A

  The present invention has been made in view of the above-mentioned problems, and an object of the present invention is a cool black tone with a good silver tone and an output with respect to fluctuations in oscillation wavelength when exposed using a laser scanning exposure machine. A silver salt photothermographic imaging material in which the sensitivity and maximum density of an image are extremely stable and the color, density, fog and sensitivity of the image are hardly deteriorated by the action of light or heat during storage, and the imaging material are used An image recording method is provided.

  The above object of the present invention can be achieved by the following constitution.

(Claim 1)
In a silver salt photothermographic imaging material having an image forming layer containing a non-photosensitive organic silver salt, silver halide, a silver ion reducing agent and a binder on a support, at least one kind of the silver ion reducing agent is represented by the following general formula: A compound represented by the formula (1), comprising a yellow color-forming leuco dye and a cyan color-forming leuco dye on the side having the image forming layer, and the yellow color-forming leuco dye and the general formula (1) The addition ratio of the compounds represented (number of moles of the yellow color-forming leuco dye / number of moles of the compound represented by formula (1)) is 0.001 to 0.2, and the cyan color-forming leuco dye And the addition ratio of the compound represented by the general formula (1) (number of moles of the cyan color-forming leuco dye / number of moles of the compound represented by the general formula (1)) is 0.001 to 0.5. Silver salt photothermography Imaging material.

(Wherein R ₁₁ and R ₁₂ each independently represents a hydrogen atom, an aliphatic group or an aromatic group. R ₁₃ and R ₁₄ each independently represent a hydrogen atom, an aliphatic group, an aromatic group or a heterocyclic ring) Q represents a substitutable group on the benzene ring, and n represents an integer of 0 to 2. When Q is plural, each Q may be the same or different.
(Claim 2)
The addition ratio of the yellow color-forming leuco dye and the compound represented by the general formula (1) (the number of moles of the yellow color-forming leuco dye / the number of moles of the compound represented by the general formula (1)) is 0.001. The silver salt photothermographic imaging material according to claim 1, wherein the silver salt photothermographic imaging material is .about.0.1.

(Claim 3)
The addition ratio of the cyan color-forming leuco dye and the compound represented by the general formula (1) (the number of moles of the cyan color-forming leuco dye / the number of moles of the compound represented by the general formula (1)) is 0.001. The silver salt photothermographic imaging material according to claim 1, wherein the silver salt photothermographic imaging material is .about.0.3.

(Claim 4)
The silver salt photothermographic imaging material according to any one of claims 1 to 3, wherein the yellow color-forming leuco dye is a compound represented by the following general formula (2).

(In the formula, R ₁ represents an alkyl group or a cycloalkyl group, R ₂ represents a hydrogen atom, an alkyl group, a cycloalkyl group, or an acylamino group, provided that R ₁ and R ₂ are 2-hydroxyphenylmethyl groups. R ₃ represents a hydrogen atom, an alkyl group or a cycloalkyl group, and R ₄ represents a substituent which can be substituted on the benzene ring.
(Claim 5)
The silver salt photothermographic imaging material according to any one of claims 1 to 3, wherein the yellow color-forming leuco dye is a compound represented by the following general formula (3).

(In the formula, R ₃₁ , R ₃₂ , R ₃₃ and R ₃₄ each independently represents an alkyl group or cycloalkyl group having 1 to 20 carbon atoms. R ₃₅ represents a hydrogen atom, an aliphatic group, an aromatic group or a hetero group. Represents a cyclic group.)
(Claim 6)
The silver salt photothermographic imaging material according to any one of claims 1 to 3, wherein the cyan color-forming leuco dye is a compound represented by the following general formula (CL).

(Wherein R _c1 and R _c2 are a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, alkenyl group, alkoxy group, —NHCO—R _c6 group (R _c6 is an alkyl group, aryl group, heterocyclic group) Or R _c1 and R _c2 represent a group which is bonded to each other to form an aliphatic hydrocarbon ring, an aromatic hydrocarbon ring or a heterocyclic ring, and A _c represents a —NHCO— group, —CONH -. a group or a -NHCONH- group, a where R _c3 substituted or unsubstituted, alkyl group, aryl group or heterocyclic group also, -A _c -R _c3 may be of a hydrogen atom .W _c Is a hydrogen atom or —CONH—R _c5 group, —CO—R _c7 group or —CO—O—R _c7 group (R _c7 represents a substituted or unsubstituted alkyl group, aryl group or heterocyclic group). represents, R _c4 is a hydrogen atom, a halogen atom, a substituted or unsubstituted , Alkyl group, alkenyl group, alkoxy group, a carbamoyl group or a nitrile group,, R _c5 is -CONH-R _c8 group, -CO-R _c8 group or -CO-O-R _c8 group (R _c8 is a substituted or Represents an unsubstituted alkyl group, aryl group, or heterocyclic group.), And X _c represents a substituted or unsubstituted aryl group or heterocyclic group.)
(Claim 7)
The silver salt photothermographic imaging material according to claim 1, wherein the silver halide is infrared sensitized.

(Claim 8)
The silver salt photothermographic imaging material according to any one of claims 1 to 7, further comprising at least one selected from a heteroaromatic mercapto compound and a heteroaromatic disulfide compound.

(Claim 9)
The hue angle hab of the silver salt photothermographic imaging material after thermally developing the silver salt photothermographic imaging material according to any one of claims 1 to 8, wherein 180 ° <hab <270 °. An image forming method.

  According to the present invention, the silver tone is a cool black tone, and when exposed using a laser scanning exposure machine, the sensitivity of the output image and the maximum density are extremely stable against fluctuations in the oscillation wavelength, In addition, it is possible to provide a silver salt photothermographic imaging material in which the color, density, fog and sensitivity of an image are hardly deteriorated by the action of light and heat during storage, and an image recording method using the imaging material.

  The present invention is described in detail below.

  The silver salt photothermographic imaging material of the present invention is a silver salt photothermographic imaging material having an image forming layer containing a non-photosensitive organic silver salt, a silver halide, a silver ion reducing agent and a binder on a support. At least one silver ion reducing agent is a compound represented by the general formula (1), and contains a yellow color developing leuco dye and a cyan color developing leuco dye on the side having the image forming layer, and the yellow Addition ratio of the chromogenic leuco dye and the compound represented by the general formula (1) (number of moles of the yellow chromophoric leuco dye / number of moles of the compound represented by the general formula (1)) is 0.001 to 0 2 and the addition ratio of the cyan color-forming leuco dye and the compound represented by the general formula (1) (number of moles of the cyan color-forming leuco dye / number of moles of the compound represented by the general formula (1)) ) Is 0.001 And one of the features that it is 0.5.

  First, the compound (silver ion reducing agent) represented by the general formula (1) according to the present invention will be described.

In the general formula (1), R ₁₁ and R ₁₂ each independently represents a hydrogen atom, an aliphatic group or an aromatic group.

  As used herein, the term “aliphatic group” means an alkyl group, a cycloalkyl group, an alkenyl group, a cycloalkenyl group, an alkynyl group, or an aralkyl group, each of which is substituted or unsubstituted.

Specific examples of the aliphatic group represented by R ₁₁ and R ₁₂ include methyl group, ethyl group, propyl group, isopropyl group, normal butyl group, tert-butyl group, pentyl group, hexyl group, decyl group, dodecyl group. , Pentadecyl group, vinyl group, allyl group, ethynyl group, propargyl group, cyclopropyl group, cyclobutyl group, cyclobutenyl group, cyclopentyl group, cyclopentenyl group, cyclopentadienyl group, cyclohexyl group, cyclohexenyl group, cyclohexadienyl group , Cycloheptyl, cycloheptynyl, cycloheptadienyl, cyclooctanyl, cyclooctenyl, cyclooctadienyl, cyclooctatrienyl, cyclononanyl, cyclononenyl, cyclononadienyl, cyclononatrienyl Group, cyclodeca Group, Shikurodekeniru group, a cycloalkyl decadienyl group, and a cyclo tetradecatrienyl group.

  These groups may have a substituent at any position. Specific examples of the substituent include an alkyl group, a halogenated alkyl group, a halogen atom, a cyano group, an alkoxy group, a hydroxy group, an amino group, and a carboxyl group. Group, carbooxy group, aryl group, heterocyclic group, aryloxy group, acyloxy group, carbamoyloxy group, alkoxycarbonyloxy group, aryloxycarbonyloxy group, and the like.

The aromatic group represented by R ₁₁ and R ₁₂ may be a single ring or a condensed ring, and examples thereof include phenyl, naphthyl, anthracenyl, phenanthrenyl, naphthacenyl, triphenylenyl and the like. These rings may have various substituents at arbitrary positions, and preferred substituents include, for example, linear and branched alkyl groups (preferably having 1 to 20 carbon atoms such as methyl group, ethyl group, etc. Group, propyl group, isopropyl group, dodecyl group, etc.), alkoxy group (preferably having 1 to 20 carbon atoms, such as methoxy group, ethoxy group, propoxy group, isopropoxy group, dodecyloxy group, etc.), aliphatic acylamino group ( Preferred are those having an alkyl group having 1 to 21 carbon atoms, such as acetylamino group and heptylamino group, and aromatic acylamino groups.

R ₁₁ is preferably a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, more preferably a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, still more preferably a methyl group, an ethyl group, an isopropyl group, or a cyclohexyl group. .

R ₁₂ is preferably a hydrogen atom.

R ₁₃ and R ₁₄ represent a hydrogen atom, an aliphatic group, an aromatic group, or a heterocyclic group. Specific examples of the aliphatic group and the aromatic group represented by R ₁₃ and R ₁₄ include the above R ₁₁ and R ₁₄ Examples thereof include the same groups as the examples of the aliphatic group and aromatic group represented by R ₁₂ .

Specific examples of the heterocyclic group represented by R ₁₃ and R ₁₄ include a pyridyl group, a quinolyl group, an isoquinolyl group, an imidazolyl group, a pyrazolyl group, a triazolyl group, an oxazolyl group, a thiazolyl group, an oxadiazolyl group, a thiadiazolyl group, Aromatic heterocyclic groups such as tetrazolyl groups and non-aromatic heterocyclic groups such as piperidino groups, morpholino groups, tetrahydrofuryl groups, tetrahydrothienyl groups and tetrahydropyranyl groups can be mentioned. These groups may further have a substituent, and examples of the substituent include the same substituents as the substituents on the ring of the aromatic group described above.

In the most preferred combination of R ₁₃ and R ₁₄ , R ₁₃ is a primary alkyl group (for example, methyl group, ethyl group, etc.) or a tertiary alkyl group (for example, tert-butyl group, 1-methylcyclohexyl group, etc.). And R ₁₄ is a primary alkyl group (eg, a methyl group, an ethyl group, etc.).

  Q represents a substitutable group on the benzene ring, specifically, an alkyl group having 1 to 25 carbon atoms (methyl group, ethyl group, propyl group, isopropyl group, tert-butyl group, pentyl group, hexyl group, Cyclohexyl group, etc.), halogenated alkyl group (trifluoromethyl group, perfluorooctyl group, etc.), cycloalkyl group (cyclohexyl group, cyclopentyl group, etc.), alkynyl group (propargyl group, etc.), glycidyl group, acrylate group, methacrylate group , Aryl groups (phenyl group, etc.), heterocyclic groups (pyridyl group, thiazolyl group, oxazolyl group, imidazolyl group, furyl group, pyrrolyl group, pyrazinyl group, pyrimidinyl group, pyridazinyl group, selenazolyl group, sriphoranyl group, piperidinyl group, pyrazolyl Group, tetrazolyl group, etc.), halogen atom (salt Atom, bromine atom, iodine atom, fluorine atom, etc.), alkoxy group (methoxy group, ethoxy group, propyloxy group, pentyloxy group, cyclopentyloxy group, hexyloxy group, cyclohexyloxy group, etc.), aryloxy group (phenoxy group) Etc.), alkoxycarbonyl group (methyloxycarbonyl group, ethyloxycarbonyl group, butyloxycarbonyl group etc.), aryloxycarbonyl group (phenyloxycarbonyl group etc.), sulfonamide group (methanesulfonamide group, ethanesulfonamide group, Butanesulfonamide group, hexanesulfonamide group, cyclohexanesulfonamide group, benzenesulfonamide group, etc.), sulfamoyl group (aminosulfonyl group, methylaminosulfonyl group, dimethylaminosulfonyl group, butyrate) Aminosulfonyl group, hexylaminosulfonyl group, cyclohexylaminosulfonyl group, phenylaminosulfonyl group, 2-pyridylaminosulfonyl group, etc.), urethane group (methylureido group, ethylureido group, pentylureido group, cyclohexylureido group, phenylureido group, 2-pyridylureido group, etc.), acyl group (acetyl group, propionyl group, butanoyl group, hexanoyl group, cyclohexanoyl group, benzoyl group, pyridinoyl group, etc.), carbamoyl group (aminocarbonyl group, methylaminocarbonyl group, dimethylamino) Carbonyl group, propylaminocarbonyl group, pentylaminocarbonyl group, cyclohexylaminocarbonyl group, phenylaminocarbonyl group, 2-pyridylaminocarbonyl group, etc.), amide group ( Acetamide group, propionamide group, butanamide group, hexaneamide group, benzamide group, etc.), sulfonyl group (methylsulfonyl group, ethylsulfonyl group, butylsulfonyl group, cyclohexylsulfonyl group, phenylsulfonyl group, 2-pyridylsulfonyl group, etc.), Amino group (amino group, ethylamino group, dimethylamino group, butylamino group, cyclopentylamino group, anilino group, 2-pyridylamino group, etc.), cyano group, nitro group, sulfo group, carboxyl group, hydroxyl group, oxamoyl group, etc. Can be mentioned. Further, these groups may be further substituted with these groups.

  n represents an integer of 0 to 2, and most preferably n is 0. When Q is plural, each Q may be the same or different.

  Although the specific example of a compound of General formula (1) is shown below, this invention is not limited to these.

  Next, the yellow color-forming leuco dye used in the present invention will be described.

  In the present invention, known yellow color-forming leuco dyes can be used. In particular, leuco dyes preferably used as yellow color-forming leuco dyes are represented by the general formula (2) in which the absorbance at 360 to 450 nm increases when oxidized. Color image forming agent. The compound of the general formula (2) that is preferably used will be described in detail.

In the general formula (2), R ₁ represents an alkyl group or a cycloalkyl group.

The alkyl group or cycloalkyl group represented by R ₁ is preferably an alkyl group or cycloalkyl group having 1 to 30 carbon atoms, and the alkyl group or cycloalkyl group may be unsubstituted or may have a substituent. Specific examples of the unsubstituted alkyl group or cycloalkyl group include methyl group, ethyl group, butyl group, octyl group, isopropyl group, tert-butyl group, tert-octyl group, tert-amyl group, sec-butyl group, A cyclohexyl group, 1-methyl-cyclohexyl group and the like are preferable, and a group sterically larger than the isopropyl group (for example, isopropyl group, isononyl group, tert-butyl group, tert-amyl group, tert-octyl group, cyclohexyl group, 1 -Methyl-cyclohexyl group, adamantyl group and the like are more preferable, and among them, tertiary alkyl groups such as tert-butyl group, tert-octyl group, and tert-amyl group are particularly preferable. When R ₁ has a substituent, the substituent is a halogen atom, aryl group, alkoxy group, amino group, acyl group, acylamino group, alkylthio group, arylthio group, sulfonamido group, acyloxy group, oxycarbonyl group, carbamoyl group , Sulfamoyl group, sulfonyl group, phosphoryl group and the like.

R ₂ represents a hydrogen atom, an alkyl group, a cycloalkyl group or an acylamino group.

Alkyl or cycloalkyl group R ₂ represents preferably an alkyl group or a cycloalkyl group having 1 to 30 carbon atoms, an acylamino group represented by R ₂ is preferably an acylamino group having 1 to 30 carbon atoms.

The description of the alkyl group or cycloalkyl group is the same as that for R ₁ . A hydrogen atom or an unsubstituted alkyl group having 1 to 24 carbon atoms is preferable, and specific examples include a methyl group, an isopropyl group, and a tert-butyl group.

  The acylamino group may be unsubstituted or substituted, and specific examples include an acetylamino group, an alkoxyacetylamino group, and an aryloxyacetylamino group. Preferably, it is an acetylamino group.

R ₁ and R ₂ are not a 2-hydroxyphenylmethyl group.

R ₃ represents a hydrogen atom, an alkyl group or a cycloalkyl group. The alkyl group or cycloalkyl group represented by R ₃ is preferably an alkyl group having 1 to 30 carbon atoms, and the description of the alkyl group is the same as in the case of R ₁ .

R ₃ is preferably a hydrogen atom, an unsubstituted alkyl group having 1 to 24 carbon atoms or a cycloalkyl group, and specific examples include a methyl group, an isopropyl group, a tert-butyl group, and a cyclohexyl group. Moreover, it is preferable that either one of R ₂ and R ₃ is a hydrogen atom.

R ₄ represents a group substitutable on the benzene ring, and is, for example, the same group as the group described for Q in the general formula (1).

Preferred groups as R ₄ are an alkyl group having 1 to 30 carbon atoms and an oxycarbonyl group having 2 to 30 carbon atoms, and an alkyl group having 1 to 24 carbon atoms is more preferred. 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 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.

  Among the compounds represented by the general formula (2), a more preferable structure is represented by the general formula (3). Next, the compound represented by the general formula (3) will be described in detail.

In the general formula (3), R ₃₁ , R ₃₂ , R ₃₃ and R ₃₄ are each independently an alkyl group or a cycloalkyl group having 1 to 20 carbon atoms. The substituent on the alkyl group or cycloalkyl group is not particularly limited, but preferably an aryl group, hydroxy group, alkoxy group, aryloxy group, alkylthio group, arylthio group, acylamino group, sulfonamide group, sulfonyl group Group, phosphoryl group, acyl group, carbamoyl group, ester group, halogen atom and the like.

In R ₃₁ , R ₃₂ , R ₃₃ and R ₃₄ , a group sterically larger than the isopropyl group (for example, isopropyl group, isononyl group, tert-butyl group, tert-amyl group, tert-octyl group, cyclohexyl group, 1-methyl-cyclohexyl group, adamantyl group, etc.) are preferably present, more preferably two or more. Tertiary alkyl groups such as tert-butyl, tert-octyl, and tert-amyl groups are particularly preferred as being sterically larger than the isopropyl group.

R ₃₅ in the general formula (3) represents a hydrogen atom, an aliphatic group, an aromatic group or a heterocyclic group. The explanation of the aliphatic group, aromatic group or heterocyclic group represented by R ₃₅ is the explanation of the aliphatic group, aromatic group or heterocyclic group represented by R ₁₃ and R ₁₄ in the general formula (1). It is the same.

R ₃₅ is preferably a hydrogen atom or an alkyl group having 1 to 15 carbon atoms, and the alkyl group is preferably a methyl group, an ethyl group, a propyl group, an isopropyl group, or a 2,4,4-trimethylpentyl group. R ₃₅ is particularly preferably a hydrogen atom.

  Specific examples of the yellow color-forming leuco dyes represented by the general formula (2) and the general formula (3) are shown below, but the present invention is not limited thereto.

  The ratio of the yellow color-forming leuco dye added to the developer in the present invention (number of moles of the yellow color-forming leuco dye / number of moles of the compound represented by the general formula (1)) is 0.001 to 0.2. , Preferably 0.001 to 0.1.

  In the present invention, the sum of the maximum densities at the maximum absorption wavelength of a dye image formed with a yellow color-forming leuco dye is preferably 0.01 or more and 0.50 or less, more preferably 0.01 or more and 0.30. Hereinafter, it is particularly preferable that the color is developed so as to have 0.02 or more and 0.10 or less.

  Next, the cyan color-forming leuco dye used in the present invention will be described.

  In the present invention, a known cyan coloring dye is used as the cyan coloring dye. Preferably, it is a color image forming agent that increases its absorbance at 600 to 700 nm when oxidized, and disclosed in JP 59-206831 (particularly a compound having a λmax in the range of 600 to 700 nm), JP Compounds of general formula (I) to general formula (IV) in Japanese Patent No. 204087 (specifically, compounds of (1) to (18) described in “0032” to “0037”) and JP-A No. 11-231460 In general formula 4 to general formula 7 (specifically, compounds No. 1 to No. 79 described in “0105”).

  Examples of the cyan color-forming leuco dye used in the present invention include compounds represented by the general formula (CL).

In general formula (CL), R _c1 and R _c2 are a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, alkenyl group, alkoxy group, —NHCO—R _c6 group (R _c6 is an alkyl group, aryl group, Represents a heterocyclic group), or R _c1 and R _c2 are bonded to each other to form an aliphatic hydrocarbon ring, an aromatic hydrocarbon ring or a heterocyclic ring. A _c represents a —NHCO— group, a —CONH— group or a —NHCONH— group, and R _c3 represents a substituted or unsubstituted alkyl group, aryl group or heterocyclic group. Further, -A _c -R _c3 may be a hydrogen atom. W _c represents a hydrogen atom, a —CONH—R _c5 group, a —CO—R _c7 group, or a —CO—O—R _c7 group (R _c7 represents a substituted or unsubstituted alkyl group, aryl group, or heterocyclic group. R _c4 represents a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, alkenyl group, alkoxy group, carbamoyl group, or nitrile group. R _c5 represents a —CONH—R _c8 group, a —CO—R _c8 group or a —CO—O—R _c8 group (R _c8 represents a substituted or unsubstituted alkyl group, aryl group or heterocyclic group). . X _c represents a substituted or unsubstituted aryl group or heterocyclic group.

In the general formula (CL), examples of the halogen atom represented by R _c1 and R _c2 include a fluorine atom, a bromine atom, and a chlorine atom, and the alkyl group is an alkyl group having up to 20 carbon atoms ( For example, a methyl group, an ethyl group, a butyl group, a dodecyl group, etc. are mentioned. As the alkenyl group, an alkenyl group having up to 20 carbon atoms (for example, a vinyl group, an allyl group, a butenyl group, a hexenyl group, a hexadienyl group, an ethenyl group). 2-propenyl group, 3-butenyl group, 1-methyl-3-propenyl group, 3-pentenyl group, 1-methyl-3-butenyl, etc.), and the alkoxy group is an alkoxy group having up to 20 carbon atoms. (For example, methoxy group, ethoxy and the like). Examples of the alkyl group represented by R _c6 in the —NHCO—R _c6 group include alkyl groups having up to 20 carbon atoms (for example, a methyl group, an ethyl group, a butyl group, a dodecyl group, etc.), and an aryl group Examples of the group include groups having 6 to 20 carbon atoms such as a phenyl group, a naphthyl group, and a thienyl group. Examples of the heterocyclic group include a thiophenyl group, a furyl group, an imidazolyl group, a pyrazolyl group, and a pyrrolyl group. Can be mentioned.

The alkyl group represented by R _c3 is preferably an alkyl group having up to 20 carbon atoms, and examples thereof include a methyl group, an ethyl group, a butyl group, and a dodecyl group, and the aryl group preferably has 6 to 6 carbon atoms. 20 aryl groups such as a phenyl group, a naphthyl group, and a thienyl group. Examples of the heterocyclic group include a thiophene group, a furan group, an imidazole group, a pyrazole group, and a pyrrole group.

In the —CONH—R _c7 group, —CO—R _c7 group or —CO—O—R _c7 group represented by W _c , the alkyl group represented by R _c7 is preferably an alkyl group having up to 20 carbon atoms. Examples thereof include a methyl group, an ethyl group, a butyl group, and a dodecyl group, and an aryl group is preferably an aryl group having 6 to 20 carbon atoms, such as a phenyl group, a naphthyl group, and a thienyl group. Examples of the heterocyclic group include a thiophenyl group, a furyl group, an imidazolyl group, a pyrazolyl group, and a pyrrolyl group. R _c7 is preferably a phenyl group, more preferably a phenyl group having a plurality of halogen atoms and cyano groups as substituents.

Examples of the halogen atom represented by R _c4 include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. Examples of the alkyl group include a chain or cyclic alkyl group such as a methyl group, a butyl group, and dodecyl. Group, cyclohexyl group, etc., and examples of the alkoxy group include methoxy group, butoxy group, tetradecyloxy group, and the like, and examples of the carbamoyl group include diethylcarbamoyl group, phenylcarbamoyl group, and the like. Nitrile groups are also preferred. Among these, a hydrogen atom and an alkyl group are more preferable. R _c3 and R _c4 may be connected to each other to form a ring structure.

  The above group may further have a substituent, and specific examples thereof include an alkyl group (methyl group, ethyl group, propyl group, isopropyl group, tert-butyl group, pentyl group, hexyl group, cyclohexyl group, etc.) , Halogenated alkyl groups (trifluoromethyl group, perfluorooctyl group, etc.), cycloalkyl groups (cyclohexyl group, cyclopentyl group, etc.), aromatic groups (phenyl group, etc.), heterocyclic groups (pyridyl group, thiazolyl group, oxazolyl) Group, imidazolyl group, furyl group, pyrrolyl group, pyrazinyl group, pyrimidinyl group, pyridazinyl group, selenazolyl group, sriphoranyl group, piperidinyl group, pyrazolyl group, tetrazolyl group, etc.), halogen atom (chlorine atom, bromine atom, iodine atom, fluorine) Atom), alkoxy group (methoxy group, ethoxy group, propyl) Xy group, pentyloxy group, cyclopentyloxy group, hexyloxy group, cyclohexyloxy group, etc.), aryloxy group (phenoxy group, etc.), alkoxycarbonyl group (methyloxycarbonyl group, ethyloxycarbonyl group, butyloxycarbonyl group, etc.) , Aryloxycarbonyl group (phenyloxycarbonyl group, etc.), sulfonamide group (methanesulfonamide group, ethanesulfonamide group, butanesulfonamide group, hexanesulfonamide group, cyclohexanesulfonamide group, benzenesulfonamide group, etc.), sulfamoyl Group (aminosulfonyl group, methylaminosulfonyl group, dimethylaminosulfonyl group, butylaminosulfonyl group, hexylaminosulfonyl group, cyclohexylaminosulfonyl group, phenyl Minosulfonyl group, 2-pyridylaminosulfonyl group, etc.), urethane group (methylureido group, ethylureido group, pentylureido group, cyclohexylureido group, phenylureido group, 2-pyridylureido group, etc.), acyl group (acetyl group, propionyl) Group, butanoyl group, hexanoyl group, cyclohexanoyl group, benzoyl group, pyridinoyl group, etc.), carbamoyl group (aminocarbonyl group, methylaminocarbonyl group, dimethylaminocarbonyl group, propylaminocarbonyl group, pentylaminocarbonyl group, cyclohexylamino) Carbonyl group, phenylaminocarbonyl group, 2-pyridylaminocarbonyl group, etc.), amide group (acetamide group, propionamide group, butanamide group, hexaneamide group, benzamide group, etc.), Sulfonyl group (methylsulfonyl group, ethylsulfonyl group, butylsulfonyl group, cyclohexylsulfonyl group, phenylsulfonyl group, 2-pyridylsulfonyl group, etc.), amino group (amino group, ethylamino group, dimethylamino group, butylamino group, cyclopentyl) Amino group, anilino group, 2-pyridylamino group, etc.), cyano group, nitro group, sulfo group, carboxyl group, hydroxyl group, oxamoyl group and the like.

In the —CONH—R _c8 group, —CO—R _c8 group or —CO—O—R _c8 group represented by R _c5 , the alkyl group represented by R _c8 is preferably an alkyl group having up to 20 carbon atoms. Yes, for example, a methyl group, an ethyl group, a butyl group, a dodecyl group, and the like. The aryl group is preferably an aryl group having 6 to 20 carbon atoms, and examples thereof include a phenyl group, a naphthyl group, and a thienyl group. Examples of the heterocyclic group include a thiophenyl group, a furyl group, an imidazolyl group, a pyrazolyl group, and a pyrrolyl group.

As the substituent that the group represented by R _c8 can have, the same substituents as those in R _{c1 to} R _c4 can be used.

Examples of the aryl group represented by X _c include aryl groups having 6 to 20 carbon atoms such as a phenyl group, a naphthyl group, and a thienyl group. Examples of the heterocyclic group include a thiophenyl group, a furyl group, and imidazolyl. Group, pyrazolyl group, pyrrolyl group and the like. _Examples of the substituent that the group represented by X _c can have include the substituents _{exemplified in} the description of R _{c1 to} R _c4 .

The group represented by _Xc is preferably an aryl group or heterocyclic group having an alkylamino group (such as a diethylamino group) at the para position. These groups may include photographically useful groups.

  Specific examples of the cyan coloring leuco dye (CL) are shown below, but the cyan coloring leuco dye used in the present invention is not limited thereto.

  The addition ratio of the cyan coloring leuco dye (number of moles of the cyan coloring leuco dye / number of moles of the compound represented by the general formula (1)) is 0.001 to 0.5, preferably 0.001. ~ 0.3.

  In the present invention, the sum of the highest densities at the maximum absorption wavelength of a dye image formed with a cyan leuco dye is preferably 0.01 or more and 0.50 or less, more preferably 0.01 or more and 0.30. Hereinafter, it is particularly preferable that the color is developed so as to have 0.02 or more and 0.10 or less.

  Photosensitive silver halide grains (also referred to simply as silver halide grains) used in the silver salt photothermographic dry imaging material of the present invention (also referred to simply as the light-sensitive material of the present invention) will be described. The photosensitive silver halide grains in the present invention can inherently absorb light as an intrinsic property of silver halide crystals, or artificially generate visible light or infrared light by a physicochemical method. Physicochemical changes in the silver halide crystal and / or on the crystal surface when absorbing light in any region within the light wavelength range from the ultraviolet light region to the infrared light region. Refers to silver halide crystal grains that have been processed and produced so that can occur.

(Photosensitive silver halide grains)
The photosensitive silver halide grains themselves according to 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 method such as an acidic method, a neutral method, and an ammonia method 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, a combination thereof, and the like. 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.

  Grain formation is usually divided into two stages: silver halide seed grain (nucleus) generation and grain growth, and these may be performed continuously at one time. Alternatively, the nucleus (seed grain) formation and grain growth may be separated. The method of performing may be used. The controlled double jet method, in which particles are formed by controlling pAg, pH, etc., which are particle forming conditions, is preferable because the particle shape and size can be controlled. For example, when performing a method of separating nucleation and grain growth, first, soluble silver salt and soluble halogen salt are uniformly and rapidly mixed in an aqueous gelatin solution to produce nuclei (seed grains) (nucleation process). Thereafter, 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. After the formation of the grains, the desired salt halide emulsion can be obtained by removing unnecessary salts by a desalting step by a known desalting method such as a noodle method, a flocculation method, an ultrafiltration method, or an electrodialysis method. I can do it.

  The photosensitive silver halide grains according to the present invention preferably have a small average particle diameter in order to keep the white turbidity and color tone (yellowishness) after image formation low and to obtain good image quality. As a value when particles less than 0.02 μm are excluded from measurement, 0.035 μm or more and 0.055 μm or less are preferable. The grain size here means 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.

Variation coefficient 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, tetradecahedral grains, tabular grains, spherical grains, rod-like grains, and potato-like grains. Among these, cubic, octahedral, and tetrahedral Tabular silver halide grains are preferred.

  When tabular silver halide grains are used, the average aspect ratio 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.

  There is no particular limitation on the crystal habit on the outer surface of the silver halide grain, but when using a spectral sensitizing dye having crystal habit (plane) selectivity in the adsorption reaction of the silver 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. 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 forming the grains, 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. Low molecular weight gelatin can be hydrolyzed by adding gelatin-degrading enzyme to a commonly used gelatin aqueous solution with an average molecular weight of about 100,000, heating by adding acid or alkali, and heating under atmospheric pressure or pressure. Can be obtained by thermal decomposition, decomposition by ultrasonic irradiation, or a combination of these methods.

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

  For the silver halide grains used in the present invention, it is preferable to use a polyethylene oxide compound represented by the following general formula when the grains are formed.

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 a hydrogen atom, an alkali metal atom, an ammonium group, or an ammonium group substituted with an alkyl group having 5 or less carbon atoms, 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 comprises a step of producing a gelatin aqueous solution, a step of adding a water-soluble halide and a water-soluble silver salt to the gelatin solution, and an emulsion. It has been preferably used as an antifoaming agent for significant foaming when the emulsion raw material is stirred or moved, such as a step of coating on a support. 44-9497. 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% by mass 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 or You may add and use for the silver salt aqueous solution and halide aqueous solution which are used at the time of formation. Preferably, it is used by adding 0.01% to 2.0% by weight to the aqueous halide solution or both aqueous solutions. Further, it is preferable to exist for at least 50% of the nucleation step, and more preferably for 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 ° C. to 60 ° C., preferably 15 ° C. 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. The temperature is gradually raised during the formation, and the temperature at the end of nucleation is preferably 40 ° C.) and vice versa, it is preferable to control within the above temperature range.

The concentration of the silver salt aqueous solution and halide aqueous solution used for nucleation is preferably 3.5 mol / liter or less, and more preferably used in a low concentration range of 0.01 mol / liter to 2.5 mol / liter. 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 pH 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.

  The silver halide grains according to the present invention may be added to the photosensitive layer (also simply referred to as a photosensitive layer) by any method. At this time, the silver halide grains are added to a reducible silver source (aliphatic carboxylic acid silver salt). It is preferable to arrange them close to each other.

  The silver halide according to the present invention is prepared in advance, and this is added to a solution for preparing the aliphatic carboxylate silver salt grains. The silver halide preparation step and the aliphatic carboxylate silver salt grain preparation step However, as described in British Patent No. 1,447,454, when preparing aliphatic carboxylic acid silver salt particles, halogen components such as halide ions are added to the fatty acid. By coexisting with an aliphatic carboxylate silver salt-forming component and injecting silver ions therein, the aliphatic carboxylate silver salt particles can be produced almost simultaneously. It is also possible to prepare silver halide grains by converting a halogen-containing silver salt into an aliphatic carboxylic acid silver salt and converting the aliphatic carboxylic acid silver salt. 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 silver halide grain forming components include inorganic halogen compounds, onium halides, halogenated hydrocarbons, N-halogen compounds, and other halogen-containing compounds. Specific examples thereof are described in US Pat. No. 4,009,039. No. 3,457,075, No. 4,003,749, British Patent No. 1,498,956 and JP-A Nos. 53-27027 and 53-25420. Inorganic halides such as ammonium halides, for example, onium halides such as trimethylphenylammonium bromide, cetylethyldimethylammonium bromide, trimethylbenzylammonium bromide, such as iodoform, bromoform, carbon tetrachloride, 2-bromo-2-methyl Halogenated hydrocarbons such as propane N-halogen compounds such as N-bromosuccinimide, N-bromophthalimide, N-bromoacetamide, and others, such as triphenylmethyl chloride, triphenylmethyl bromide, 2-bromoacetic acid, 2-bromoethanol, dichlorobenzophenone Etc. Thus, silver halide can also be prepared by converting a part or all of silver in the organic acid silver salt into silver halide by the reaction between the organic acid silver and the halogen ion. Moreover, you may use together the silver halide grain manufactured by converting a part of aliphatic carboxylic acid silver salt into the silver halide prepared separately.

  These silver halide grains are 0.001 mol to 0.7 mol with respect to 1 mol of aliphatic carboxylic acid silver salt, both separately prepared silver halide particles and silver halide particles obtained by conversion of aliphatic carboxylic acid silver salt. Preferably, 0.03 mol to 0.5 mol is used.

  The silver halide grains according to the present invention preferably contain ions of transition metals belonging to Groups 6 to 11 of the periodic table. As the metal, W, Fe, Co, Ni, Cu, Ru, Rh, Pd, Re, Os, Ir, Pt, and Au are preferable. These may be used alone or in combination of two or more of the same or different metal complexes.

For these metal ions, a metal salt may be introduced as it is into silver halide, but can be introduced into silver halide in the form of a metal complex or complex ion. The preferred content is in the range of 1 × 10 ⁻⁹ mol to 1 × 10 ⁻² mol, and more preferably in the range of 1 × 10 ⁻⁸ to 1 × 10 ⁻⁴ with ^respect to 1 mol of silver. 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 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 halides (fluoride, chloride, bromide and iodide), cyanide, cyanate, thiocyanate, selenocyanate, tellurocyanate, azide and aco. A ligand, nitrosyl, thionitrosyl and the like can be mentioned, and ako, nitrosyl, thionitrosyl and the like are preferable. 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 , May be added at any stage before or after chemical sensitization, but is preferably added at the stage of nucleation, growth and physical ripening, more preferably at the stage of nucleation and growth, most preferably Preferably, it is added at the stage of nucleation. In addition, it may be divided and added several times, or it can be uniformly contained in the silver halide grains. 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 and NaCl, KCl are dissolved together is added to the water-soluble silver salt solution or water-soluble halide solution during particle formation, or the silver salt solution and the 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 liquids, a method of introducing an aqueous solution of a required amount of a metal compound into a reaction vessel during grain formation, or a silver halide preparation 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 necessary 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.

  Separately prepared photosensitive silver halide grains can be desalted by known desalting methods such as noodle method, flocculation method, ultrafiltration method, electrodialysis method, etc., but can also be used without desalting. .

(Non-photosensitive organic silver salt)
The non-photosensitive organic silver salt according to the present invention is a reducible silver source, is a salt of an organic acid containing silver ions, and is non-photosensitive. As the organic acid used in the present invention, aliphatic carboxylic acid, carbocyclic carboxylic acid, heterocyclic carboxylic acid, heterocyclic compound and the like are used.

  Examples of non-photosensitive organic acid silver salts according to the present invention are described in Research Disclosure Nos. 17029 and 29963, and silver salts of aliphatic carboxylic acids (for example, gallic acid, oxalic acid, behenic acid, arachidic acid, Silver salts of stearic acid, palmitic acid, lauric acid, etc.); silver carboxyalkylthiourea salts (for example, 1- (3-carboxypropyl) thiourea, 1- (3-carboxypropyl) -3,3-dimethylthiourea, etc. ); A silver complex of a polymerization reaction product of an aldehyde and a hydroxy-substituted aromatic carboxylic acid (for example, aldehydes (formaldehyde, acetaldehyde, butyraldehyde, etc.) and hydroxy-substituted aromatic carboxylic acids (for example, salicylic acid, benzoic acid, 3, 5-dihydroxybenzoic acid, 5,5-thiodisalicylic acid, etc. A silver complex of a polymerization reaction product with thione, a silver salt or a complex of thiones (for example, 3- (2-carboxyethyl) -4-hydroxymethyl-4-thiazoline-2-thione, and 3-carboxymethyl- 4-thiazoline-2-thione), imidazole, pyrazole, urazole, 1,2,4-thiazole and 1H-tetrazole, nitrogen selected from 3-amino-5-benzylthio-1,2,4-triazole and benzotriazole Examples include acid and silver complexes or salts; silver salts such as saccharin and 5-chlorosalicylaldoxime; and silver salts of mercaptides.

  Among the organic silver salts described above, a silver salt of an aliphatic carboxylic acid is preferably used, and a silver salt of an aliphatic carboxylic acid having 10 to 30 carbon atoms, more preferably 15 to 25 carbon atoms. Examples of suitable silver salts include the following.

  Silver salts such as gallic acid, succinic acid, behenic acid, stearic acid, arachidic acid, palmitic acid and lauric acid. Among these, preferable silver salts include silver behenate, silver arachidate, and silver stearate. In the present invention, it is preferable that two or more types 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. For example, two or more types of aliphatic carboxylic acid salts are used. It is preferable to prepare by mixing a silver ion solution with an acid mixture.

  The aliphatic carboxylic acid silver salt compound can be 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, silver halide grains may be mixed.

  In the aliphatic carboxylic acid silver salt according to the present invention, the average equivalent circle diameter can be adjusted in the range of 0.05 μm to 0.8 μm from the viewpoint of improving the transparency of the image after heat development and improving the image storage stability. Preferably, silver ions are appropriately supplied during heat development, and the average thickness is preferably adjusted to 0.005 μm to 0.07 μm, particularly preferably from the viewpoint of improving the storage stability of the obtained image. The average equivalent circle diameter is 0.2 μm to 0.5 μm, and the average thickness is adjusted to a range of 0.01 μm to 0.05 μm.

  To obtain the average equivalent circle diameter, the dispersed aliphatic carboxylic acid silver salt is diluted and dispersed on a grid with a carbon support film, and the transmission electron microscope (manufactured by JEOL Ltd., 2000FX type) is directly increased to 5000 times magnification. I took a picture. The negative is captured as a digital image with a scanner, and 300 or more particle sizes (equivalent circle diameter) are measured using appropriate image processing software, and the average particle size is calculated.

  The average thickness is calculated by a method using a TEM (transmission electron microscope) as shown below.

  First, the photosensitive layer coated on the support is attached to an appropriate holder with an adhesive, and an ultrathin slice having a thickness of 0.1 to 0.2 μm is produced using a diamond knife in a direction perpendicular to the support surface. . The prepared ultra-thin slice is supported on a copper mesh, transferred onto a carbon film that has been hydrophilized by glow discharge, and cooled with liquid nitrogen to −130 ° C. or lower using a transmission electron microscope (hereinafter referred to as TEM). The bright field image is observed at a magnification of 5,000 to 40,000, and the image is quickly recorded on a film, an imaging plate, a CCD camera or the like. At this time, it is preferable to appropriately select a portion where the section is not torn or slack as the field of view to be observed.

  As the carbon film, it is preferable to use a very thin collodion, formbar, or the like supported by an organic film. More preferably, the carbon film is formed on a rock salt substrate and dissolved and removed. It is a carbon-only film obtained by solvent and ion etching. The acceleration voltage of TEM is preferably 80 to 400 kV, particularly preferably 80 to 200 kV.

  In addition, for details of electron microscope observation techniques and sample preparation techniques, see “The Japan Electron Microscopy Society Kanto Branch / Medical and Biological Electron Microscopy” (Maruzen), “The Japan Electron Microscopy Society Kanto Branch / Electron Microscope Biological Samples” "Manufacturing method" (Maruzen) can be referred to respectively.

  A TEM image recorded on an appropriate medium is preferably decomposed into at least 1024 pixels × 1024 pixels, preferably 2048 pixels × 2048 pixels or more, and image processing by a computer is performed. In order to perform image processing, it is preferable that an analog image recorded on a film is converted into a digital image by a scanner or the like, and shading correction, contrast / edge enhancement, and the like are performed as necessary. Thereafter, a histogram is prepared, and a portion corresponding to the aliphatic carboxylate silver is extracted by binarization processing.

  300 or more of the extracted aliphatic carboxylic acid silver salt particles are manually measured with appropriate software to obtain an average value.

  The method for obtaining the aliphatic carboxylic acid silver salt particles having the above-mentioned shape is not particularly limited, but the mixed state at the time of forming the organic acid alkali metal salt soap and / or the mixed state at the time of adding silver nitrate to the soap, etc. It is effective to maintain a good balance, optimize the ratio of organic acid to soap, and the ratio of silver nitrate that reacts with soap.

  Tabular aliphatic carboxylic acid silver salt particles used in the present invention (aliphatic carboxyl having an average equivalent circle diameter of 0.05 μm or more and 0.8 μm or less and an average thickness of 0.005 μm or more and 0.07 μm or less The acid silver salt particles) are preferably preliminarily dispersed together with a binder, a surfactant or the like, if necessary, and then dispersed and ground with a media disperser or a high-pressure homogenizer. For the preliminary dispersion, a general stirrer such as an anchor type or a propeller type, a high-speed rotating centrifugal radiation type stirrer (dissolver), or a high-speed rotating shear type stirrer (homomixer) can be used.

In addition, as the media dispersing machine, a rolling mill such as a ball mill, a planetary ball mill, and a vibrating ball mill, a bead mill that is a medium agitation mill, an attritor, and other basket mills can be used, and a wall as a high-pressure homogenizer. Various types can be used, such as a type that collides with a plug or the like, a type in which liquids are collided at a high speed after dividing the liquid, and a type in which a thin orifice is passed.

Examples of ceramics used for the ceramic beads used when dispersing the media include Al ₂ O ₃ , BaTiO ₃ , SrTiO ₃ , MgO, ZrO, BeO, Cr ₂ O ₃ , SiO ₂ , SiO ₂ —Al ₂ O ₃ , Cr. ₂ O ₃ —MgO, MgO—CaO, MgO—C, MgO—Al ₂ O ₃ (spinel), SiC, TiO ₂ , K ₂ O, Na ₂ O, BaO, PbO, B ₂ O ₃ , SrTiO ₃ (titanium) _{strontium), BeAl 2 O 4, Y} 3 Al 5 O 12, ZrO 2 -Y 2 O 3 ( cubic _{zirconia), 3BeO-Al 2 O 3} -6SiO 2 ( synthesis emerald), C (diamond), Si ₂ O—nH ₂ O, ticker silicon, yttrium-stabilized zirconia, zirconia-reinforced alumina, and the like are preferable. Yttrium-stabilized zirconia and zirconia-reinforced alumina (ceramics containing these zirconia are hereinafter abbreviated as zirconia) are particularly preferably used because of the low generation of impurities due to friction with beads and dispersers during dispersion.

  In the apparatus used for dispersing the tabular aliphatic carboxylic acid silver salt particles used in the present invention, zirconia, alumina, silicon nitride, boron nitride, etc. are used as the material of the member in contact with the aliphatic carboxylic acid silver salt particles. These ceramics or diamond are preferably used, and zirconia is particularly preferable. When the above dispersion is performed, the binder concentration is preferably added in an amount of 0.1 to 10% of the mass of the aliphatic silver carboxylate, and it is preferable that the liquid temperature does not exceed 45 ° C. from the preliminary dispersion to the main dispersion. As preferable operating conditions for the present dispersion, for example, when a high-pressure homogenizer is used as the dispersing means, the preferable operating conditions are 29.42 to 98.06 MPa, and the number of operations is preferably 2 times or more. Further, when the media disperser is used as the dispersing means, the peripheral speed is preferably 6 m / sec to 13 m / sec.

  In the present invention, the compound that functions as a crystal growth inhibitor or dispersant for the aliphatic carboxylate silver particles refers to a silver aliphatic carboxylate under the conditions in which the compound coexists in the production process of the aliphatic carboxylate particles. A compound having a function and an effect of reducing the particle size or monodispersing than when it is produced under conditions that do not coexist. Specific examples include monohydric alcohols having 10 or less carbon atoms, preferably secondary alcohols, tertiary alcohols, glycols such as ethylene glycol and propylene glycol, polyethers such as polyethylene glycol, and glycerin. A preferable addition amount is 10% by mass to 200% by mass with respect to the aliphatic carboxylate silver.

  On the other hand, branched aliphatic carboxylic acids containing isomers such as isoheptanoic acid, isodecanoic acid, isotridecanoic acid, isomyristic acid, isopalmitic acid, isostearic acid, isoarachidic acid, isobehenic acid and isohexaconic acid are also preferred. In this case, a preferable side chain includes an alkyl group or an alkenyl group having 4 or less carbon atoms. In addition, aliphatic unsaturated carboxylic acids such as palmitoleic acid, oleic acid, linoleic acid, linolenic acid, moloctic acid, eicosenoic acid, arachidonic acid, eicosapentaenoic acid, erucic acid, docosapentaenoic acid, docosahexaenoic acid, and ceracolonic acid It is done. A preferable addition amount is 0.5 mol% to 10 mol% of silver aliphatic carboxylate.

  Glycosides such as glucoside, galactoside, fructoside, trehalose type disaccharides such as trehalose and sucrose, polysaccharides such as glycogen, dextrin, dextran and alginic acid, cellosolves such as methyl cellosolve and ethyl cellosolve, sorbitan, sorbit, ethyl acetate, acetic acid Water-soluble organic solvents such as methyl and dimethylformamide, water-soluble polymers such as polyvinyl alcohol, polyacrylic acid, acrylic acid copolymer, maleic acid copolymer, carboxymethylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, polyvinylpyrrolidone and gelatin Are also preferred compounds. A preferable addition amount is 0.1% by mass to 20% by mass with respect to aliphatic silver carboxylate.

  Alcohols having 10 or less carbon atoms, preferably secondary alcohols and tertiary alcohols are monodispersed and small in viscosity by increasing the solubility of sodium aliphatic carboxylate in the charging step and increasing the stirring efficiency. Grain size. Branched aliphatic carboxylic acids and aliphatic unsaturated carboxylic acids have higher steric hindrance than the main component linear aliphatic carboxylic acid silver when crystallization of the aliphatic carboxylic acid silver, and the disorder of the crystal lattice is large. Therefore, large crystals are not generated, and as a result, the particle size is reduced.

  As described above, compared with the conventional silver halide photographic light-sensitive material, the biggest difference in the structure of the silver salt photothermographic dry imaging material is that the latter material, before and after the development processing, That is, it contains a large amount of photosensitive silver halide, organic silver salt and reducing agent that may cause fogging and printout silver (baked-out silver). For this reason, silver salt photothermographic dry imaging materials require advanced antifogging and image stabilization techniques in order to maintain storage stability not only before development but also after development. In addition to aromatic heterocyclic compounds that inhibit growth and 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 mercury compounds has been a problem in terms of safety and environmental conservation.

(Anti-fogging agent, image stabilizer)
The antifogging and image stabilizer used in the silver salt photothermographic dry imaging material of the present invention will be described below.

  In the silver salt photothermographic dry imaging material of the present invention, as will be described later, a reducing agent of bisphenols is mainly used as the reducing agent, so that active species capable of extracting these hydrogens are generated. It is preferable that the compound which can inactivate a reducing agent by this is contained. A colorless photo-oxidizable substance is preferably a compound capable of generating free radicals as reactive active species during exposure.

  Accordingly, any compound having these functions may be used, but an organic free radical composed of a plurality of atoms is preferred. A compound having any structure may be used as long as it has such a function and does not cause any particular adverse effects on the silver salt photothermographic dry imaging material.

  In addition, these free radical-generating compounds are carbocyclic or heterocyclic in order to give the generated free radicals stable enough to be in contact with a reducing agent for a time sufficient to inactivate them. Those having the following aromatic group are preferred.

  Representative examples of these compounds include biimidazolyl compounds and iodonium compounds listed below.

  As the biimidazolyl compound, a compound represented by the following general formula [1] is preferably used.

In the formula, each of R ₁ , R ₂ and R ₃ (same or different) is an alkyl group (eg, methyl group, ethyl group, hexyl group, etc.), alkenyl group (eg, vinyl group, allyl group), alkoxy Group (for example, methoxy group, ethoxy group, octyloxy group), aryl group (for example, phenyl group, naphthyl group, tolyl group), hydroxyl group, halogen atom, aryloxy group (for example, phenoxy group), alkylthio group (for example, , Methylthio group, butylthio group), arylthio group (for example, phenylthio group), acyl group (for example, acetyl group, propionyl group, butyryl group, valeryl group), sulfonyl group (for example, methylsulfonyl group, phenylsulfonyl group, etc.), An acylamino group, a sulfonylamino group, an acyloxy group (for example, an acetoxy group, Nzokishi group), showing a carboxyl group, a cyano group, a sulfo group or an amino group. Among these, more preferred substituents are an aryl group, an alkenyl group, a cyano group, and the like.

  The above-mentioned biimidazolyl compound can be produced by the production methods described in US Pat. No. 3,734,733 and British Patent No. 1,271,177 and methods according thereto. As a preferable specific example, the compound example described in Unexamined-Japanese-Patent No. 2000-321711 can be mentioned, for example.

  Similarly, a suitable compound includes an iodonium compound represented by the following general formula [2].

Wherein Q ¹ includes the atoms necessary to complete a 5, 6 or 7 membered ring, and the required atoms are selected from carbon atoms, nitrogen atoms, oxygen atoms and sulfur atoms. Each of R ¹ , R ² and R ³ (same or different) is a hydrogen atom, an alkyl group (for example, methyl group, ethyl group, hexyl group, etc.), an alkenyl group (for example, vinyl group, allyl group, etc.), alkoxy Group (for example, methoxy group, ethoxy group, octyloxy group, etc.), aryl group (for example, phenyl group, naphthyl group, tolyl group, etc.), hydroxyl group, halogen atom, aryloxy group (for example, phenoxy group), alkylthio group (For example, methylthio group, butylthio group), arylthio group (for example, phenylthio group), acyl group (for example, acetyl group, propionyl group, butyryl group, valeryl group, etc.), sulfonyl group (for example, methylsulfonyl group, phenylsulfonyl group) Etc.), acylamino group, sulfonylamino group, acyloxy group (for example, ace Alkoxy group, benzoxy group), showing a carboxyl group, a cyano group, a sulfo group and an amino group. Among these, more preferred substituents are an aryl group, an alkenyl group, and a cyano group.

R ⁴ represents a carboxylate group such as acetate, benzoate or trifluoroacetate and O 2 ⁻ . W represents 0 or 1.

X ⁻ is an anionic counter ion, and preferred examples are CH ₃ CO ₂ ⁻ , CH ₃ SO ₃ ⁻ and PF ₆ ⁻ .

When R ³ is a sulfo group or a carboxyl group, W is 0 and R ⁴ is O ⁻ .

In addition, any of R ¹ , R ² and R ³ may be bonded to each other to form a ring.

  Among these, a particularly preferable compound is represented by the following general formula [3].

^{Wherein, R 1, R 2, R} 3, R 4, X - and W and the like are the same meaning as the general formula (2), Y is a carbon atom; or represents (-CH = benzene ring), or Represents a nitrogen atom (-N =; pyridine ring).

  The above iodonium compounds are described in Org. Syn. , 1961 and "Advanced Organic Chemistry by Fieser" (Reinhold, NY, 1961) and a method analogous thereto.

  As a preferable specific example, the compound example described in Unexamined-Japanese-Patent No. 2000-321711 can be mentioned, for example.

The amount of the compound represented by the general formulas [1] and [2] is 10 ⁻³ to 10 ⁻¹ mol / m ² , preferably 5 × 10 ^{−3 to} 5 × 10 ⁻² mol / m ^2. It is. The compound can be contained in any constituent layer in the light-sensitive material of the present invention, but is preferably contained in the vicinity of the reducing agent.

  Further, as a compound that inactivates the reducing agent and prevents the reducing agent from reducing the aliphatic carboxylic acid silver salt to silver, a compound in which the reactive species is not a halogen atom is preferable, but a compound that releases a halogen atom as an active species is also available. Can be used in combination with a compound that releases an active species that is not a halogen atom. Many compounds capable of releasing a halogen atom as an active species are known, and a good effect can be obtained by the combined use.

  Specific examples of the compound that generates these active halogen atoms include compounds represented by the following general formula [4].

In the general formula [4], 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, a phenyl group, a naphthyl group, etc.) More preferred are a phenyl group and a naphthyl group, and even more preferred is 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. As the heterocyclic ring in such a heterocyclic group, 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, benzothiazole, 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, benzothiazole, tetrazaindene, more preferably imidazole, pyridine, pyrimidine, pyrazine, pyridazine, triazole, triazine, thiadiazole, quinoline, phthalazine, naphthyridine, Quinoxaline, quinazoline, cinnoline, tetrazole, thiazole, benzimidazole, and benzothiazole are preferable, and pyridine, thiadiazole, quinoline, and benzothiazole 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 .

The substituents represented by X ₁ , X ₂ and X ₃ are each preferably a halogen atom, a haloalkyl group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a carbamoyl group, a sulfamoyl group, a sulfonyl group or a heterocyclic group. Is more preferably a halogen atom, a haloalkyl group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a sulfonyl group (alkylsulfonyl group, arylsulfonyl group), more preferably a halogen atom or a trihalomethyl group, Particularly preferred is 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 is, -C (= O) -, - SO- or, -SO ₂ - represents a, among them preferably used is, -SO ₂ - is.

  The amount of these compounds added is preferably within a range in which the increase in printout silver due to the formation of silver halide does not become a problem, and the ratio to the compound that does not generate active halogen radicals is 150% or less, more preferably It is preferable that it is 100% or less.

  In addition to the above compounds, the silver salt photothermographic dry imaging material of the present invention may contain a compound conventionally known as an antifoggant, but has the same reaction activity as the above compound. Even if it is a compound which can produce | generate a seed | species, the compound from which an antifogging mechanism differs may be sufficient. For example, U.S. Pat. Nos. 3,589,903, 4,546,075, 4,452,885, JP-A-59-57234, U.S. Pat. No. 3,874,946, No. 4,756,999, JP-A-9-288328 and JP-A-9-90550. Further, other antifoggants include compounds disclosed in US Pat. No. 5,028,523 and European Patents 600,587, 605,981, and 631,176. .

  In the present invention, the silver ion reducing agent is preferably a bisphenol derivative represented by the general formula (1). 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. In the present invention, it may be preferable that 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, because photographic performance fluctuation due to stagnation time is small. is there.

  The photosensitive silver halide according to the present invention can be chemically sensitized. For example, a chemical sensitization center can be obtained by using a compound that releases chalcogen such as sulfur or a noble metal compound that releases noble metal ions such as gold ions by the method described in Japanese Patent Application No. 2000-57004 and Japanese Patent Application Laid-Open No. 2001-249426. (Chemically sensitized nuclei) can be formed and imparted. It is preferably chemically sensitized with an organic sensitizer containing chalcogen atoms shown below.

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

  As these organic sensitizers, organic sensitizers having various structures disclosed in JP-A-60-150046, JP-A-4-109240, JP-A-11-218874, and the like can be used. Of these, at least one compound having a structure in which a chalcogen atom is bonded to a carbon atom or a phosphorus atom by a double bond is preferable.

The amount of the chalcogen compound used as the organic sensitizer varies depending on the chalcogen compound used, silver halide grains, reaction environment for chemical sensitization, etc., but is 10 ⁻⁸ to 10 ⁻ per mol of silver halide. ² mol is preferred, more preferably 10 ⁻⁷ to 10 ⁻³ mol. The chemical sensitization environment is not particularly limited, but in the presence of a compound capable of annihilating or reducing the size of silver chalcogenide or silver nuclei on photosensitive silver halide grains, and in particular oxidizing silver nuclei. It is preferable to perform chalcogen sensitization using an organic sensitizer containing a chalcogen atom in the presence of an oxidant that can be used. As the sensitization condition, pAg is preferably 6 to 11, more preferably 7 to The pH is preferably 4 to 10, more preferably 5 to 8, and the temperature is preferably 30 ° C. or lower for sensitization.

  Therefore, in the silver salt photothermographic dry imaging material of the present invention, the photosensitive silver halide uses an organic sensitizer containing a chalcogen atom in the presence of an oxidizing agent capable of oxidizing silver nuclei on the grain. It is preferable to use a photosensitive emulsion which has been chemically sensitized at a temperature of 30 ° C. or lower, mixed with an aliphatic carboxylic acid silver salt, dispersed, dehydrated and dried.

  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, the heterocyclic ring includes 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, Examples thereof include three bonded rings such as a triazolotriazole ring, a diazaindene ring, a triazaindene ring, and a pentaazaindene ring. 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 benzothiazole 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, a tetrahydroxyazaindene, a 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. May be.

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 10 ^-6 per mole of silver halide. The range is from mol to ¹ mol, preferably from 10 ⁻⁴ mol to 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.

  In addition to the above sensitization methods, reduction sensitization methods and the like can also be used. Examples of reduction sensitization compounds include ascorbic acid, thiourea dioxide, stannous chloride, hydrazine derivatives, and borane. A 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.

  The silver halide subjected to chemical sensitization may be formed in the presence of an organic silver salt, formed in the absence of an organic silver salt, or a mixture of both. .

  The photosensitive silver halide according to 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 are described in, for example, the literature described or cited in Section RD17643IV-A (December 1978, p.23), Section 18431X (August 1978, p.437). ing. 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 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 above basic nucleus. 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.

  As the infrared spectral sensitizing dye, a long-chain polymethine dye characterized in that a sulfinyl group is substituted on the benzene ring of the benzoazole ring is particularly preferable.

  The above-mentioned infrared sensitizing dyes are described in, for example, HM Hammer, The Chemistry of Heterocyclic Compounds, Vol. 18, The Cyanine Dies and Related Compounds, published by A. Weissberger ed. It can be synthesized with reference to the method.

  These infrared sensitizing dyes may be added at any time after the preparation of the silver halide. For example, the silver halide grains or the silver halide grains / in a so-called solid dispersion state added to a solvent or dispersed in the form of fine particles. It can be added to a photosensitive emulsion containing 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 adding and adsorbing 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, the above-mentioned spectral sensitizing dyes may be used alone or in combination, and the combination of sensitizing dyes is often used for the purpose of supersensitization.

  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 RD17643 (issued in December, 1978), page 23, Section J, or Japanese Patent Publication No. 9-25500, 43-4933, JP-A-59-19032, JP-A-59-192242, JP-A-5-341432, and the like. Examples of supersensitizers include heteroaromatic mercapto represented by the following. A compound 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, benzothiazole, naphthothiazole, benzoxazole, naphthoxazole, benzoselenazole, benzotelrazole, imidazole, oxazole, pyrazole, triazole, triazine, pyrimidine, pyridazine, pyrazine, pyridine , Purine, quinoline, or quinazoline. However, other heteroaromatic rings are also included.

  In addition, a mercapto derivative compound which substantially forms the above mercapto compound when contained in a dispersion of an aliphatic carboxylic acid silver salt and / or a silver halide grain emulsion is 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 is, for example, a halogen atom (for example, Cl, Br, I), a hydroxyl group, an amino group, a carboxyl group, an alkyl group (for example, one or more carbon atoms, preferably 1 to 4 carbon atoms). And a substituent selected from the group consisting of an alkoxy group (for example, one having one or more carbon atoms, preferably 1 to 4 carbon atoms).

  In addition to the supersensitizer described above, compounds represented by the following general formula [5] described in Japanese Patent Application No. 2000-70296 and macrocyclic compounds can be used as the supersensitizer.

In the formula, H ₃₁ Ar represents an aromatic hydrocarbon group or an aromatic heterocyclic group, T ₃₁ represents a divalent linking group or linking group composed of an aliphatic hydrocarbon group, and J ₃₁ represents an oxygen atom or a sulfur atom. Alternatively, it represents a divalent linking group or linking group containing one or more nitrogen atoms. Ra, Rb, Rc and Rd each represent a hydrogen atom, an acyl group, an aliphatic hydrocarbon group, an aryl group or a heterocyclic group, or between Ra and Rb, Rc and Rd, Ra and Rc, or Rb and Rd. It can combine to form a nitrogen-containing heterocyclic group. M31 represents an ion necessary to cancel the charge in the molecule, and k31 represents the number of ions required to cancel the charge in the molecule.

In the general formula [5], the divalent linking group composed of the aliphatic hydrocarbon group represented by T ₃₁ is a linear, branched or cyclic alkylene group (preferably having 1 to 20 carbon atoms, more preferably 1). -16, more preferably 1-12), an alkenyl group (preferably 2-20 carbons, more preferably 2-16, still more preferably 2-12), an alkynyl group (preferably 2-20 carbons, more preferably). 2 to 16 and more preferably 2 to 12), which may have a substituent, for example, as an aliphatic hydrocarbon group, a linear, branched or cyclic alkyl group (preferably having a carbon number of 1 to 20, more preferably 1-16, still more preferably 1-12, alkenyl group (preferably 2-20 carbon atoms, more preferably 2-16, still more preferably 2-12), alkynyl group (preferably carbon number). 2 20, more preferably 2-16, and still more preferably 2-12), and examples of the aryl group include monocyclic or condensed ring aryl groups having 6 to 20 carbon atoms (for example, phenyl, naphthyl, etc.). Is a phenyl group, and the heterocyclic group is a 3- to 10-membered saturated or unsaturated heterocyclic group (for example, 2-thiazolyl, 1-piperazinyl, 2-pyridyl, 3-pyridyl, 2-furyl, 2-furyl, Thienyl group, 2-benzimidazolyl group, carbazolyl group, etc.), and the heterocycle in these groups may be a single ring or may form a condensed ring with another ring. Each of these groups may have a substituent at an arbitrary position, for example, an alkyl group (including a cycloalkyl group and an aralkyl group, preferably having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, Particularly preferred are those having 1 to 8 carbon atoms, for example, methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, tert-butyl group, n-heptyl group, n-octyl group, n -Decyl group, n-undecyl group, n-hexadecyl group, cyclopropyl group, cyclopentyl group, cyclohexyl group, benzyl group, phenethyl group, etc.), alkenyl group (preferably having 2 to 20 carbon atoms, more preferably). 2 to 12 carbon atoms, particularly preferably 2 to 8 carbon atoms, and examples thereof include a vinyl group, an allyl group, a 2-butenyl group, and a 3-pentenyl group. Nyl group (preferably having 2 to 20 carbon atoms, more preferably 2 to 12 carbon atoms, and particularly preferably 2 to 8 carbon atoms, such as propargyl group and 3-pentynyl group), aryl group ( Preferably it has 6 to 30 carbon atoms, more preferably 6 to 20 carbon atoms, particularly preferably 6 to 12 carbon atoms, and examples thereof include a phenyl group, a p-tolyl group, an O-aminophenyl group, and a naphthyl group. .), An amino group (preferably having a carbon number of 0 to 20, more preferably a carbon number of 0 to 10, particularly preferably a carbon number of 0 to 6, such as an amino group, a methylamino group, an ethylamino group, a dimethylamino group. , Diethylamino group, diphenylamino group, dibenzylamino group, etc.), imino group (preferably having 1 to 20 carbon atoms, more preferably having 1 to 18 carbon atoms, particularly preferably Or an alkoxy group (preferably having a carbon number of 1 to 20, more preferably a carbon number of 1 to 12, particularly preferably a carbon atom), for example, a methylimino group, an ethylimino group, a propylimino group, or a phenylimino group. For example, a methoxy group, an ethoxy group, a butoxy group, etc.), an aryloxy group (preferably having 6-20 carbon atoms, more preferably 6-16 carbon atoms, and particularly preferably 6-12 carbon atoms). Yes, for example, phenyloxy group, 2-naphthyloxy group and the like, acyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, Acetyl group, benzoyl group, formyl group, pivaloyl group, etc.), alkoxycarbonyl group (preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, Particularly preferably, it has 2 to 12 carbon atoms, for example, a methoxycarbonyl group, an ethoxycarbonyl group, etc., an aryloxycarbonyl group (preferably 7 to 20 carbon atoms, more preferably 7 to 16 carbon atoms, particularly preferably carbon numbers). 7-10, for example, phenyloxycarbonyl group, etc., acyloxy group (preferably having 1-20 carbon atoms, more preferably having 1-16 carbon atoms, particularly preferably having 1-10 carbon atoms, such as acetoxy group, benzoyl Oxy group, etc.), acylamino group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 10 carbon atoms such as acetylamino group, benzoylamino group), alkoxycarbonylamino group (Preferably 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 2 carbon atoms. 2 and, for example, methoxycarbonylamino, etc., aryloxycarbonylamino group (preferably having 7 to 20 carbon atoms, more preferably 7 to 16 carbon atoms, particularly preferably 7 to 12 carbon atoms, such as phenyloxycarbonylamino ), Sulfonylamino groups (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as methanesulfonylamino group, benzenesulfonylamino group, etc.), sulfamoyl groups (Preferably has 0 to 20 carbon atoms, more preferably has 0 to 16 carbon atoms, and particularly preferably has 0 to 12 carbon atoms. For example, sulfamoyl group, methylsulfamoyl group, dimethylsulfamoyl group, phenylsulfamoyl group, etc. ), A carbamoyl group (preferably having 1 to 20 carbon atoms, more preferably 1 carbon atom) 16, particularly preferably 1 to 12 carbon atoms, for example, carbamoyl group, methylcarbamoyl group, diethylcarbamoyl group, phenylcarbamoyl group, etc., alkylthio group (preferably 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms). Particularly preferably, it has 1 to 12 carbon atoms, such as a methylthio group, an ethylthio group, etc., an arylthio group (preferably 6 to 20, more preferably 6 to 16 carbon atoms, particularly preferably 6 to 12 carbon atoms). , For example, phenylthio group), sulfonyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as methanesulfonyl group and tosyl group), sulfinyl group (Preferably 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms. Examples thereof include a methanesulfinyl group and a benzenesulfinyl group. ), Ureido groups (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as ureido group, methylureido group, phenylureido group), phosphoric acid amide Group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as diethyl phosphoric acid amide, phenyl phosphoric acid amide), hydroxyl group, mercapto group, halogen Atom (for example, fluorine atom, chlorine atom, bromine atom, iodine atom), cyano group, sulfo group, sulfino group, carboxyl group, phosphono group, phosphino group, nitro group, hydroxamic acid group, hydrazino group, heterocyclic group (for example, , Imidazolyl, benzimidazolyl, thiazolyl, benzothiazolyl, carbazolyl, pyridyl, furyl, pipette Jill, like morpholino, etc.) and the like.

  Among the above groups, a salt-forming group such as a hydroxyl group, a mercapto group, a sulfo group, a sulfino group, a carboxyl group, a phosphono group, or a phosphino group may be a salt. These substituents may be further substituted. Moreover, when there are two or more substituents, they may be the same or different. The substituent is preferably an alkyl group, aralkyl group, alkoxy group, aryl group, alkylthio group, acyl group, acylamino group, imino group, sulfamoyl group, sulfonyl group, sulfonylamino group, ureido group, amino group, halogen atom, nitro Group, heterocyclic group, alkoxycarbonyl group, hydroxyl group, sulfo group, carbamoyl group, carboxyl group, more preferably alkyl group, alkoxy group, aryl group, alkylthio group, acyl group, acylamino group, imino group, sulfonylamino Group, ureido group, amino group, halogen atom, nitro group, heterocyclic group, alkoxycarbonyl group, hydroxyl group, sulfo group, carbamoyl group, carboxyl group, more preferably alkyl group, alkoxy group, aryl group, alkylthio group A Arylamino group, an imino group, a ureido group, an amino group, a heterocyclic group, an alkoxycarbonyl group, a hydroxyl group, a sulfo group, a carbamoyl group, a carboxyl group. Examples of the amidino group include those having a substituent. Examples of the substituent include an alkyl group (for example, each group such as methyl, ethyl, pyridylmethyl, benzyl, phenethyl, carboxybenzyl, and aminophenylmethyl), an aryl group. (For example, phenyl, p-tolyl, naphthyl, o-aminophenyl, o-methoxyphenyl, etc.), a heterocyclic group (for example, 2-thiazolyl, 2-pyridyl, 3-pyridyl, 2-furyl, 3- Furyl, 2-thieno, 2-imidazolyl, benzothiazolyl, carbazolyl and the like) and the like.

Examples of the divalent linking group containing at least one oxygen atom, sulfur atom or nitrogen atom represented by J ₃₁ include the following. Moreover, these combinations may be sufficient.

  Here, Re and Rf are respectively synonymous with the contents defined in Ra to Rd described above.

The aromatic hydrocarbon group represented by H ₃₁ Ar is preferably one having 6 to 30 carbon atoms, more preferably a monocyclic or condensed ring aryl group having 6 to 20 carbon atoms, such as phenyl Group, a naphthyl group, etc. are mentioned, Especially preferably, it is a phenyl group. The aromatic heterocyclic group represented by H ₃₁ Ar is a 5- to 10-membered unsaturated heterocyclic group containing at least one atom of N, O and S, and the heterocyclic ring in these groups is It may be a single ring or may form a condensed ring with another ring. The heterocyclic ring in such a heterocyclic group is preferably a 5- to 6-membered aromatic heterocyclic ring and a benzo-fused ring thereof, more preferably a 5- to 6-membered aromatic heterocyclic ring containing a nitrogen atom, and The benzo-fused ring is more preferably a 5- to 6-membered aromatic heterocycle containing 1 to 2 nitrogen atoms and the benzo-fused ring.

  Specific examples of the heterocyclic group include, for example, thiophene, furan, pyrrole, imidazole, pyrazole, pyridine, pyrazine, pyridazine, triazole, triazine, indole, indazole, purine, thiadiazole, oxadiazole, quinoline, phthalazine, naphthyridine, quinoxaline. , Quinazoline, cinnoline, pteridine, acridine, phenanthroline, phenazine, tetrazole, thiazole, oxazole, benzimidazole, benzoxazole, benzothiazole, benzothiazoline, benzotriazole, tetrazaindene, carbazole, etc. . The heterocyclic group is preferably imidazole, pyrazole, pyridine, pyrazine, indole, indazole, thiadiazole, oxadiazole, quinoline, phenazine, tetrazole, thiazole, oxazole, benzimidazole, benzoxazole, benzothiazole, benzothiazoline, benzotriazole, Each group consisting of tetrazaindene and carbazole, more preferably derived from imidazole, pyridine, pyrazine, quinoline, phenazine, tetrazole, thiazole, benzoxazole, benzimidazole, benzothiazole, benzothiazoline, benzotriazole, carbazole Each group is mentioned.

The aromatic hydrocarbon group and aromatic heterocyclic group represented by H ₃₁ Ar may have a substituent, and examples of the substituent include the same groups as those exemplified as the substituent for T _31. The preferred ranges are also the same. These substituents may be further substituted, and when there are two or more substituents, each may be the same or different. The group represented by H ₃₁ Ar is preferably an aromatic heterocyclic group.

The aliphatic hydrocarbon group, aryl group and heterocyclic group represented by Ra, Rb, Rc and Rd are the same as those mentioned as examples of the aliphatic hydrocarbon group, aryl group and heterocyclic group in T ₃₁ . The preferred ranges are also the same. The acyl group represented by Ra, Rb, Rc, and Rd is an aliphatic or aromatic group having 1 to 12 carbon atoms, and specifically includes groups such as acetyl, benzoyl, formyl, and pivaloyl. The nitrogen-containing heterocyclic group formed by bonding between Ra and Rb, Rc and Rd, Ra and Rc, or Rb and Rd is a 3 to 10-membered saturated or unsaturated heterocyclic group (for example, piperidine ring, piperazine Ring, acridine ring, pyrrolidine ring, pyrrole ring, morpholine ring, etc.).

Specific examples of acid anions as ions necessary for canceling out the charge in the molecule represented by M ₃₁ include, for example, halogen ions (eg, chlorine ions, bromine ions, iodine ions, etc.), p-toluenesulfonic acid. Ions, perchlorate ions, boron tetrafluoride ions, sulfate ions, methyl sulfate ions, ethyl sulfate ions, methanesulfonate ions, trifluoromethanesulfonate ions, and the like.

  The supersensitizer used in 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.

  Binders suitable for the silver salt photothermographic dry imaging material 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) ) , Poly (urethanes), 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. For non-photosensitive layers such as overcoat layers and undercoat layers, especially protective layers and backcoat layers, cellulose esters which are polymers with higher softening temperatures, especially polymers such as triacetyl cellulose and cellulose acetate butyrate preferable. If necessary, the above binders can be used in combination of two or more.

  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. A range is preferred. That is, the binder amount of the photosensitive layer is preferably 1.5 to 6 g / m2. More preferably, it is 1.7-5 g / m2. 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 this invention, it is preferable that the heat transition point temperature after developing at the temperature of 100 degreeC or more is 46 degreeC or more and 200 degrees C or less. 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 Denshi), DSC220C (manufactured by Seiko Denshi Kogyo). DSC-7 (manufactured by Perkin Elmer Co., Ltd.) or the like is used to indicate the endothermic peak when the thermally developed photosensitive layer is isolated and measured. In general, polymer compounds have a glass transition point Tg, but in silver salt photothermographic dry imaging materials, a large endothermic peak appears below the Tg value of the binder resin used in the photosensitive layer. To do. The glass transition temperature (Tg) was determined 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 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 a binder contained in a photosensitive layer containing an aliphatic carboxylic acid silver salt, photosensitive silver halide particles, a reducing agent on a support, a conventionally known polymer is used. Compounds can be used. The Tg is 70 to 105 ° C., the number average molecular weight is 1,000 to 1,000,000, preferably 10,000 to 500,000, and the degree of polymerization is about 50 to 1,000. Examples of such include vinyl chloride, vinyl acetate, vinyl alcohol, maleic acid, acrylic acid, acrylic ester, vinylidene chloride, acrylonitrile, methacrylic acid, methacrylic ester, styrene, butadiene, ethylene, vinyl butyral, vinyl acetal, There are compounds made of a polymer or copolymer containing an ethylenically unsaturated monomer such as vinyl ether as a constituent unit, 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. There is no restriction | limiting in particular in these high molecular compounds, A homopolymer or a copolymer may be sufficient if the glass transition temperature (Tg) of the induced | guided | derived polymer exists in the range of 70-105 degreeC.

  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 [6] is particularly preferable.

In the formula, R ₅₁ 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 ₅₂ represents an unsubstituted alkyl group, a substituted alkyl group, an unsubstituted aryl group, a substituted aryl group, —COR ₅₃ or —CONHR ₅₃ . R ₅₃ has the same meaning as R ₅₁ .

The unsubstituted alkyl group represented by R ₅₁ , R ₅₂ , and R ₅₃ 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, tert-butyl, n-amyl, tert-amyl, n -Hexyl group, cyclohexyl group, n-heptyl group, n-octyl group, tert-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 and aryl group include an alkyl group (for example, methyl group, n-propyl group, tert-amyl group, tert-octyl group, n-nonyl group, dodecyl group, etc.), 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), alkoxycarbonyl group ( Eg to Metokishiruboniru 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.

As R ₅₂ , —COR ₅₃ (R ₅₃ is an alkyl group or aryl group) and —CONHR ₅₃ (R ₅₃ is an aryl group) are preferable. a, b, and c are values representing the mass of each repeating unit in mol (mol)%, a is 40 to 86 mol%, b is 0 to 30 mol%, and c is in the range of 0 to 60 mol%. A + b + c = 100 mol%, particularly preferably a is in the range of 50 to 86 mol%, b is 5 to 25 mol%, and c is 0 to 40 mol%. Each repeating unit having a composition ratio of a, b, and c may be composed of only the same one or 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 Represents an atom or an alkali metal base), —N (R ₅₄ ) ₂ , —N ⁺ (R ₅₄ ) ₃ (R ₅₄ represents a hydrocarbon group, and a plurality of R ₅₄ may be the same or different); It is preferable to use one in which at least one polar group selected from an epoxy group, —SH, —CN and the like is introduced by copolymerization or addition reaction. The amount of such a polar group is 1 × 10 ⁻¹ to 1 × 10 ⁻⁸ mol / g, preferably 1 × 10 ⁻² to 1 × 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 polyurethane molecule end. 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 .

  The polymer compound represented by the above general formula [6] according to the present invention is synthesized by a general synthesis method described in “vinyl acetate resin” edited by Ichiro Sakurada (Polymer Chemistry Publishing Society, 1962). Can do.

  These polymer compounds may be used alone as a binder, or two or more kinds may be blended and used. In the photosensitive silver salt-containing layer (preferably photosensitive layer) according to the present invention, the above polymer is used as a main binder. The main binder as used herein refers to “a state in which the polymer occupies 50% by mass or more of the total binder of the photosensitive silver salt-containing layer”. Therefore, other polymers may be blended and used within a range of less than 50% by mass of the total binder. These polymers are not particularly limited as long as the polymers according to the present invention are soluble. More preferably, polyvinyl acetate, a polyacrylic resin, a urethane resin, etc. are mentioned.

  In the present invention, it is known that the use of a crosslinking agent for the binder improves the film formation and reduces development unevenness. However, it prevents fogging during storage and produces printed silver after development. There is also an inhibitory effect.

  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-based compounds described in JP-A-50-96216. , Vinylsulfone-based, sulfonic acid ester-based, acryloyl-based, carbodiimide-based, and silane compound-based crosslinking agents can be used, but the following isocyanate-based compounds, silane compounds, epoxy compounds, or acid anhydrides are preferable.

  An isocyanate-based and thioisocyanate-based crosslinking agent represented by the following general formula [7], which is one of the preferred ones, will be described.

General formula [7]
X ₂ = C = N−L− (N = C = X ₂ ) _v
In the formula, v is 1 or 2, L is an alkyl group, alkenyl group, aryl group or alkylaryl group, a (v + 1) -valent linking group, and X ₂ is an oxygen or sulfur atom.

  In the compound represented by the general formula [7], the aryl ring of the aryl group may have a substituent. Examples of preferred substituents are selected from halogen atoms (for example, bromine atoms or chlorine atoms), hydroxyl groups, amino groups, carboxyl groups, alkyl groups and alkoxy groups.

  The isocyanate-based crosslinking agent includes isocyanates having at least two isocyanate groups and adducts thereof (adducts), and more specifically, aliphatic diisocyanates and aliphatic diisocyanates having a cyclic group. Benzene diisocyanates, naphthalene diisocyanates, biphenyl isocyanates, diphenylmethane diisocyanates, triphenylmethane diisocyanates, triisocyanates, tetraisocyanates, adducts of these isocyanates and divalent or trivalent with these isocyanates Examples include adducts with polyalcohols.

  As specific examples, isocyanate compounds described on pages 10 to 12 of JP-A-56-5535 can be used.

  Note that the adduct body of isocyanate and polyalcohol has particularly high ability to improve interlayer adhesion, and prevent layer peeling, image shift, and bubble generation. Such isocyanates may be placed in any part of the silver salt photothermographic dry imaging material. For example, in the support (especially when the support is paper, it can be included in the size composition), photosensitive layer, surface protective layer, intermediate layer, antihalation layer, subbing layer, etc. It can be added to any one of these layers, and can be added to one or more of these layers.

  As the thioisocyanate-based crosslinking agent that can be used in the present invention, compounds having a thioisocyanate structure corresponding to the above-mentioned isocyanates are also useful.

  The amount of the crosslinking agent used in the present invention is in the range of 0.001 to 2 mol, preferably 0.005 to 0.5 mol, with respect to 1 mol of silver.

  The isocyanate compound and thioisocyanate compound that can be contained in the present invention are preferably compounds that function as the above-mentioned crosslinking agent. However, in the above general formula, v is zero (0), that is, the functional group is one. Even if it is a compound which has only, a good result is obtained.

  Examples of the silane compound that can be used as a crosslinking agent in the present invention include compounds represented by general formula (1) or general formula (2) described in Japanese Patent Application No. 2000-77904.

  In these general formulas, R1, R2, R3, R4, R5, R6, R7 and R8 are each a linear, branched or cyclic alkyl group having 1 to 30 carbon atoms (methyl group, ethyl group). Butyl, octyl, dodecyl, cycloalkyl, etc.), alkenyl (propenyl, butenyl, nonenyl, etc.), alkynyl (acetylene, bisacetylene, phenylacetylene, etc.), aryl or hetero Represents a cyclic group (phenyl group, naphthyl group, tetrahydropyran group, pyridyl group, furyl group, thiophenyl group, imidazole group, thiazole group, thiadiazole group, oxadiazole group, etc.), and the substituent is an electron-withdrawing substituent. Alternatively, it can have any electron-donating substituent.

  It is preferable that at least one of the substituents selected from R1, R2, R3, R4, R5, R6, R7 and R8 is a non-diffusible group or an adsorptive group, and particularly R2 is a non-diffusible group or an adsorptive group. Preferably there is.

  The non-diffusible group is also called a ballast group, and is preferably an aliphatic group having 6 or more carbon atoms or an aryl group into which an alkyl group having 3 or more carbon atoms is introduced. Diffusion resistance varies depending on the amount of binder and cross-linking agent used. By introducing a diffusion-resistant group, the intramolecular movement distance at room temperature is suppressed, and the reaction over time can be suppressed.

  The epoxy compound that can be used as the crosslinking agent is not particularly limited as long as it has one or more epoxy groups and the number of epoxy groups, molecular weight, and the like. The epoxy group is preferably contained in the molecule as a glycidyl group via an ether bond or an imino bond. Moreover, any of a monomer, an oligomer, a polymer, etc. may be sufficient as an epoxy compound, and the number of the epoxy groups which exist in a molecule | numerator is about 1-10 normally, Preferably it is 2-4. When the epoxy compound is a polymer, it may be a homopolymer or a copolymer, and the particularly preferred range of the number average molecular weight Mn is about 2000 to 20000.

  As the epoxy compound, a compound represented by the following general formula [8] is preferable.

In the general formula [8], the substituent of the alkylene group represented by R ₉₀ is preferably a group selected from a halogen atom, a hydroxyl group, a hydroxyalkyl group, or an amino group. The linking group represented by R ₉₀ preferably has an amide linking moiety, an ether linking moiety, or a thioether linking moiety. -SO ₂ As the divalent linking group represented by _{X 9 -, - SO 2 NH} -, - S -, - O-, or -NR ₉₁ - are preferred. Here, R ₉₁ is a monovalent group and is preferably an electron withdrawing group.

These epoxy compounds may be used alone or in combination of two or more. The addition amount is not particularly limited, but is preferably in the range of 1 × 10 ⁻⁶ to 1 × 10 ⁻² mol / m ² , more preferably in the range of 1 × 10 ⁻⁵ to 1 × 10 ⁻³ mol / m ² . It is.

  The epoxy compound can be added to any layer on the photosensitive layer side of the support, such as a photosensitive layer, a surface protective layer, an intermediate layer, an antihalation layer, and an undercoat layer, and one or more of these layers can be added. Can be added. Further, it can be added to any layer on the opposite side of the support from the photosensitive layer. In addition, any layer may be sufficient in the type of photosensitive material in which a photosensitive layer exists on both surfaces.

  An acid anhydride is a compound having at least one acid anhydride group represented by the following structural formula.

-CO-O-CO-
The acid anhydride is not particularly limited as long as it has at least one such acid anhydride group, and the number, molecular weight, and the like of the acid anhydride group are not limited, but a compound represented by the general formula [9] is preferable.

  In the general formula [9], Z represents an atomic group necessary for forming a monocyclic or polycyclic system. These ring systems may be unsubstituted or substituted. Examples of substituents include alkyl groups (eg, methyl, ethyl, hexyl), alkoxy groups (eg, methoxy, ethoxy, octyloxy), aryl groups (eg, phenyl, naphthyl, tolyl), hydroxyl groups, aryloxy groups (Eg, phenoxy), alkylthio group (eg, methylthio, butylthio), arylthio group (eg, phenylthio), acyl group (eg, acetyl, propionyl, butyryl), sulfonyl group (eg, methylsulfonyl, phenylsulfonyl), acylamino group Sulfonylamino group, acyloxy group (for example, acetoxy, benzoxy), carboxyl group, cyano group, sulfo group, and amino group. As the substituent, those not containing a halogen atom are preferable.

These acid anhydrides may be used alone or in combination of two or more. The addition amount is not particularly limited, but is preferably in the range of 1 × 10 ⁻⁶ to 1 × 10 ⁻² mol / m ² , more preferably in the range of 1 × 10 ⁻⁵ to 1 × 10 ⁻³ mol / m ² . It is.

  In the present invention, the acid anhydride can be added to any layer on the photosensitive layer side of the support, such as a photosensitive layer, a surface protective layer, an intermediate layer, an antihalation layer, and an undercoat layer. It can be added to two or more layers. Moreover, you may add to the same layer as the said epoxy compound.

  The silver salt photothermographic dry imaging material of the present invention forms a photographic image by heat development processing, and is a reducible silver source (aliphatic carboxylic acid silver salt), photosensitive silver halide grains, reducing agent and necessary Accordingly, it is preferable that a toning agent for adjusting the color tone of silver is contained in a dispersed state in a normal (organic) binder matrix.

  Examples of suitable toning agents are disclosed in RD 17029, U.S. Pat. Nos. 4,123,282, 3,994,732, 3,846,136 and 4,021,249. ing. A particularly preferred colorant is a combination of phthalazinone or phthalazine with phthalic acids and phthalic anhydrides.

  In addition to the cyan color-forming leuco dye and the yellow color-forming leuco dye of the present invention, a magenta color-forming leuco dye may be further added. Examples of magenta color-forming leuco dyes that can be added include, for example, JP-A-8-507785, European Patent 339,869, US Pat. No. 3,985,565, US Pat. No. 4,022,617. And magenta color-forming leuco dyes described in the specification, and other known magenta color-forming leuco dyes. As the addition amount, an addition amount ratio (number of moles of the magenta color-forming leuco dye / number of moles of the compound represented by the general formula (1)) is preferably 0.001 to 0.5.

  Note that, regarding the color tone of an output image for medical diagnosis in the past, it is said that a cold tone image tone makes it easier for an X-ray photograph reader to obtain a more accurate diagnostic observation result of a recorded image. Here, the cool image tone is a pure black tone or a bluish black tone of a black image, and the warm image tone is a black tone of a black image having a brownish tone. To tell.

The terms “more cold” and “more warm” regarding the color tone are determined by the hue angle hab at the minimum density Dmin and the optical density D = 1.0. The hue angle hab is calculated using the color coordinates a ^* and b ^* of the 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. It is calculated by the following formula.

h _ab = tan −1 (b ^* / a ^* )
In the present invention, the preferred range of hab is 180 ° <hab <270 °, more preferably _{200 ° <h ab <270 °} , and most preferably 220 ° <hab <260 °.

  In the present invention, the surface layer of the silver salt photothermographic dry imaging material (even 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 or thermal development. It is preferable to contain a matting agent in order to prevent the subsequent image from being damaged, and it is preferable to contain 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.

  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, polycarbonate film, etc.) In the present invention, a biaxially stretched polyethylene terephthalate film is particularly preferable. The thickness of the support is about 50 μm to 300 μm, preferably 70 μm 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 the undercoat layer, the backing layer, the 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, and a back coat layer is provided on the opposite side of the support to prevent sticking between the photosensitive materials or in the photosensitive material roll. Preferably it is 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, It is chosen from among them. In order to widen the latitude, it is one of preferred embodiments of the present invention to provide two or more photosensitive layers on one side of the support or one or more layers on both sides of the support.

  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, or a dye is formed on the photosensitive layer. Or it is preferable to contain a pigment.

  As the dye used, known compounds that absorb light in various wavelength regions can be used depending on the color sensitivity of the photosensitive material.

  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 as disclosed in JP-A-2001-83655 (in this specification, a thiolium dye). Use a pyraryllium squarylium dye (referred to herein as a pyrylium squarylium dye), a thiopyrylium croconium dye similar to a squarylium dye, or a pyrylium croconium dye. Is preferred.

  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.

  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 when coating this onto a support, each layer is individually coated and dried repeatedly. In other words, it means that each constituent layer can be formed in such a state that the multilayer coating and drying can be performed simultaneously. That is, the upper layer is provided before the remaining amount of the total solvent in the lower layer reaches 70% by mass or less.

  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 coated silver amount is preferably selected in accordance with the purpose of the silver salt photothermographic imaging material, but for medical images, it is 0.1 g / m ² or more. 5 g / m ² or less is preferable. Furthermore, 0.5 g / m ² or more and 1.5 g / m ² or less are preferable. 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.

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

  In the present invention, the 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 to heat the silver salt photothermographic dry imaging material at a moderately high temperature (eg, about 100 ° C. to 200 ° C.) for a sufficient time (generally about 1 second to about 2 minutes). 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 a redox reaction between the aliphatic carboxylic acid silver salt (which functions as an oxidizing agent) and the 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 on the side 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.

  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, but 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, the exposure in the present invention is preferably performed using a laser scanning exposure machine that emits a scanning laser beam 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. A semiconductor laser; a chemical laser, a dye laser, or the like can be selected and used in a timely manner. Among these, it is preferable to use a semiconductor laser having a wavelength of 600 nm to 1200 nm in view of maintenance and the size of the light source. 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 μm to 75 μm as a minor axis diameter, The major axis diameter is in the range of 5 μm 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.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, this invention is not limited to these.

Example 1
<Production of support>
One side of a polyethylene terephthalate film base (thickness: 175 μm) colored blue with a concentration of 0.170 was subjected to a corona discharge treatment of 0.5 kV · A · min / m ² , and then the following undercoat coating solution was applied thereon. Using A, the undercoat layer a was applied so that the dry film thickness was 0.2 μm. Further, after the other surface was similarly subjected to a corona discharge treatment of 0.5 kV · A · min / m ² , the following undercoat coating solution B was used thereon to form an undercoat layer b with a dry film thickness. Was coated to be 0.1 μm.

  Thereafter, heat treatment was performed at 130 ° C. for 15 minutes in a heat treatment type oven having a film transport device composed of a plurality of roll groups.

(Undercoating liquid A)
270 g of copolymer latex liquid (solid content 30%) of 30% by mass of n-butyl acrylate, 20% by mass of tert-butyl acrylate, 25% by mass of styrene and 25% by mass of 2-hydroxyethyl acrylate, surfactant (UL-1 ) 0.6 g and methylcellulose 0.5 g were mixed. Further, 1.3 g of silica particles (Syloid 350, manufactured by Fuji Silysia) was added to 100 g of water, and dispersion treatment was performed for 30 minutes with an ultrasonic disperser (manufactured by ALEX Corporation, Ultrasonic Generator, frequency 25 kHz, 600 W). The dispersion liquid was added, and finally it was made up to 1000 ml with water to obtain an undercoat coating liquid A.

<Preparation of colloidal tin oxide dispersion>
A homogeneous solution was prepared by dissolving 65 g of stannic chloride hydrate in 2000 ml of a water / ethanol mixed solution. Subsequently, this was boiled and the coprecipitate was obtained. The generated precipitate was taken out by decantation and washed several times with distilled water. Silver nitrate is dropped into distilled water from which the precipitate has been washed, and after confirming that there is no reaction of chlorine ions, distilled water is added to the washed precipitate to make a total volume of 2000 ml. Furthermore, 40 ml of 30% aqueous ammonia was added, the aqueous solution was heated, and concentrated to a volume of 470 ml to prepare a colloidal tin oxide dispersion.

(Undercoating liquid B)
Copolymer latex liquid (solid content 30) of 37.5 g of the colloidal tin oxide dispersion, 20% by mass of n-butyl acrylate, 30% by mass of tert-butyl acrylate, 27% by mass of styrene and 28% by mass of 2-hydroxyethyl acrylate. %) 3.7 g, n-butyl acrylate 40 mass%, styrene 20 mass%, glycidyl methacrylate 40 mass% copolymer latex liquid (solid content 30%) 14.8 g and 0.1 g surfactant UL-1 Were mixed and finished to 1000 ml with water to obtain an undercoat coating solution B.

<Back side application>
While stirring 830 g of methyl ethyl ketone (hereinafter abbreviated as MEK), 84.2 g of cellulose acetate butyrate (Eastman Chemical, CAB381-20) and 4.5 g of a polyester resin (Bostic, VitelPE2200B) were added and dissolved. Next, 0.30 g of infrared dye 1 was added to the dissolved solution, and 4.5 g of F-type active agent (Asahi Glass Co., Surflon KH40) dissolved in 43.2 g of methanol and F-type active agent (Dainippon Ink, Inc.) Co., MegaFag F120K) 2.3 g was added and stirred well until dissolved. Finally, 75 g of silica (WR Grace Co., Syloid 64X6000) dispersed in methyl ethyl ketone at a concentration of 1% by mass with a dissolver type homogenizer was added and stirred to prepare a coating solution for the back surface side.

  The back surface coating solution thus prepared was applied and dried by an extrusion coater on the undercoat layer b described above so that the dry film thickness was 3.5 μm. It dried for 5 minutes using the drying air with a drying temperature of 100 degreeC, and dew point temperature of 10 degreeC.

<< Preparation of photosensitive silver halide emulsion A >>
Solution (A1)
Phenylcarbamoylated gelatin 88.3g
Compound (A) (10% methanol aqueous solution) 10 ml
Potassium bromide 0.32g
Solution finished to 5429 ml with water (B1)
0.67 mol / L silver nitrate aqueous solution 2635 ml
Solution (C1)
Potassium bromide 51.55g
Potassium iodide 1.47g
Solution to make up to 660 ml with water (D1)
Potassium bromide 154.9g
4.41 g of potassium iodide
Iridium chloride (1% solution) 0.93ml
Solution to make up to 1982ml with water (E1)
0.4 mol / L potassium bromide aqueous solution The following silver potential control amount solution (F1)
Potassium hydroxide 0.71g
Solution finished to 20 ml with water (G1)
56% acetic acid aqueous solution 18.0 ml
Solution (H1)
Anhydrous sodium carbonate 1.72 g
Finish to 151 ml with water 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 the mixing stirrer shown in Japanese Patent Publication Nos. 58-58288 and 58-58289, ¼ amount of the solution (B1) and the whole amount of the solution (C1) were adjusted to a temperature of 30 ° C. and a pAg of 8.09. While being controlled, the nucleation was performed by adding 4 minutes 45 seconds by the simultaneous mixing method. After 1 minute, the entire amount of solution (F1) was added. During this time, the pAg was adjusted as appropriate using the aqueous solution (E1). After 6 minutes, 3/4 amount of the solution (B1) and the whole amount of the solution (D1) were added over 14 minutes and 15 seconds by the simultaneous mixing method while controlling the temperature at 30 ° C. and pAg 8.09. After stirring for 5 minutes, the temperature was lowered to 40 ° C., the whole amount of the solution (G1) was added, and the silver halide emulsion was allowed to settle. 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 precipitated. 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 mol 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%.

  Next, 240 ml of sulfur sensitizer S-5 (0.5% methanol solution) was added to the above emulsion, and gold sensitizer Au-5 corresponding to 1/20 mol of this sensitizer was added, and the mixture was heated to 55 ° C. The mixture was stirred for 120 minutes for chemical sensitization. This is designated as photosensitive silver halide emulsion A.

<< Preparation of powdered aliphatic carboxylic acid silver salt A >>
130.8 g of behenic acid, 67.7 g of arachidic acid, 43.6 g of stearic acid, and 2.3 g of palmitic acid were dissolved in 4720 ml of pure water at 80 ° C. Next, 540.2 ml of 1.5M sodium hydroxide aqueous solution was added, 6.9 ml of concentrated nitric acid was added, and then cooled to 55 ° C. to obtain a fatty acid sodium solution. While maintaining the temperature of the fatty acid sodium solution at 55 ° C., 45.3 g of the above photosensitive silver halide emulsion A and 450 ml of pure water were added and stirred for 5 minutes.

  Next, 702.6 ml of a 1 mol / liter 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. Then, the cake-like aliphatic carboxylic acid silver salt thus obtained was added to the airflow dryer flash jet. Using a drier (manufactured by Seishin Enterprise Co., Ltd.), a powdered aliphatic carboxylic acid silver salt A was obtained by drying until the moisture content became 0.1% under the operating conditions of nitrogen gas atmosphere and dryer inlet hot air temperature. . An infrared moisture meter was used to measure the water content of the aliphatic carboxylic acid silver salt composition.

<< Preparation of Preliminary Dispersion A >>
While dissolving 1.57 g of polyvinyl butyral resin B-79 manufactured by Solusia in 1457 g of methyl ethyl ketone and stirring with dissolver DISPERMAT CA-40M manufactured by VMA-GETZMANN, 500 g of powdered aliphatic carboxylic acid silver salt A was gradually added. Preliminary dispersion A was prepared by adding and mixing well.

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

<< Preparation of stabilizer liquid >>
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, 1.488 g of 2-chloro-benzoic acid, 2.7779 g of stabilizer 2 and 365 mg of 5-methyl-2-mercaptobenzimidazole are darkened in 31.3 ml of MEK. The solution was dissolved at a place to prepare an infrared sensitizing dye liquid A.

<< Preparation of Additive Liquid a >>
Silver ion reducing agent (compound and amount described in Table 1), yellow chromophoric leuco dye (compound and amount described in Table 1) and cyan chromogenic leuco dye (compound and amount described in Table 1), 1.54 g 4-methylphthalic acid and 0.48 g of infrared dye 1 were dissolved in 110 g of MEK to obtain additive solution a.

<< Preparation of additive 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 solution A >>
In an inert gas atmosphere (97% nitrogen), the photosensitive emulsion dispersion A (50 g) and 15.11 g of MEK were kept at 21 ° C. with stirring, 390 μl of antifoggant 1 (10% methanol solution) was added, Stir for 1 hour. Further, 494 μl of calcium bromide (10% methanol solution) was added and stirred for 20 minutes. Subsequently, 167 ml of a 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 butyral resin B-79 manufactured by Solusia Co. was added as a binder resin 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 continuing to stir, the additive solution a (weighed so that the silver ion reducing agent, the yellow color developing leuco dye and the cyan color developing leuco dye are added in the amounts shown in Table 1), 1.6 ml of Desmodur N3300 / Mobaye The photosensitive layer coating solution A was obtained by sequentially adding and stirring the aliphatic isocyanate (10% MEK solution) of 4.27 g and the additive solution b.

<Preparation of matting agent dispersion>
Cellulose acetate butyrate (Eastman Chemical Co., 7.5 g CAB171-15) was dissolved in 42.5 g of MEK, and 5 g of calcium carbonate (Speciality Minerals, Super-Pflex 200) was added thereto, and a dissolver type homogenizer was used. The matting agent dispersion was prepared by dispersing at 8000 rpm for 30 minutes.

<< Preparation of surface protective layer coating liquid >>
While stirring 865 g of MEK (methyl ethyl ketone), 96 g of cellulose acetate butyrate (Eastman Chemical Co., CAB171-15), 4.5 g of polymethylmethacrylic acid (Rohm & Haas Co., Paraloid A-21), vinyl sulfone compound ( 1.5 g of VSC), 1.0 g of benzotriazole, and 1.0 g of F-based activator (Asahi Glass Co., Surflon KH40) were added and dissolved. Next, 30 g of the above matting agent dispersion was added and stirred to prepare a surface protective layer coating solution.

<< Preparation of Silver Salt Photothermographic Dry Imaging Material Samples 101-125 >>
Each sample was produced by simultaneously applying the photosensitive layer coating solution A and the surface protective layer coating solution on the undercoat layer a using a known extrusion coater. The coating was carried out so that the photosensitive layer had a coating silver amount of 1.5 g / m ² and the surface protective layer had a dry film thickness of 2.5 μm. Then, each sample was produced by drying for 10 minutes using a drying air having a drying temperature of 75 ° C. and a dew point temperature of 10 ° C.

<< Exposure and development process >>
From the emulsion surface side of the sample prepared as described above, exposure by laser scanning was given by an exposure machine using a semiconductor laser which was converted into a longitudinal multimode with wavelengths of 810 nm and 814 nm by high frequency superposition as an exposure source. 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. (Note that 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 sample was thermally developed at 123 ° C. for 13.5 seconds so that the protective layer of the sample was in contact with the drum surface. At that time, exposure and development were performed in a room adjusted to 23 ° C. and 50% RH. The following evaluation was performed on each image obtained as described above.

<Measurement of sensitivity, fog, and maximum concentration>
For each image obtained by exposure at each wavelength, density measurement is performed with a Macbeth densitometer (TD-904), and a characteristic curve composed of the horizontal axis; exposure amount, vertical axis: image density is created, and more than the unexposed portion. The reciprocal of the exposure ratio required to give 1.0 high density was defined as sensitivity, and minimum density (fogging) and maximum density were measured. The sensitivity of the sample 101 exposed with a 810 nm semiconductor laser was expressed as a relative value with 100 as the sensitivity.

<Measurement of hue angle hab>
The hue angle hab is measured with a spectrocolorimeter CM− in a 2 ° field of view using the minimum light density portion and the optical density 1.0 portion of the developed sample as the light source for color measurement defined by the CIE. It was determined by measurement using 508d (Minolta).

<Evaluation of image preservation>
For each image obtained by exposure with a semiconductor laser at 810 nm, the image storage stability was evaluated by measuring the image density change rate in the minimum density portion and the maximum density portion according to the following method.

(Evaluation of image storability of minimum density part)
Each of the heat-developed samples prepared in the same manner as the above-described sensitivity, fog, and maximum density measurement methods was subjected to a commercially available white fluorescent lamp with an illuminance of 500 lux on the sample surface in an environment of 45 ° C. and 55% RH. And then irradiated continuously for 3 days. Measure the minimum concentration (D ₂ ) of the sample irradiated with the fluorescent lamp and the minimum concentration (D ₁ ) of the sample not irradiated with the fluorescent lamp, and calculate the minimum density change rate (%) from the following formula. A measure of image preservation. The closer the value is to 100, the better.

Minimum density change rate = D ₂ / D ₁ × 100 (%)
(Evaluation of image storage stability at the highest density area)
Each 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 change in the maximum density is measured. It was measured and used as a measure of image preservation at the highest density part. The closer the value is to 100, the better.

Image density change rate = maximum density of sample stored at 45 ° C./maximum density of sample stored at 25 ° C. × 100 (%)
<Measurement of hue angle hab after image storage>
A sample obtained by exposure with an 810 nm semiconductor laser was irradiated continuously for 3 days in a 45 ° C. and 55% RH environment with a commercially available white fluorescent lamp arranged so that the illuminance on the sample surface was 500 lux. Thereafter, the minimum density portion and the optical density 1.0 portion were measured using a spectrophotometer CM-508d (manufactured by Minolta Co., Ltd.) with a 2 ° field of view using a regular light source D65 defined by CIE as a light source for color measurement. And asked.

  The results are shown in Table 2.

  From Table 2, the silver salt photothermographic dry imaging material of the present invention has not only good color tone but also good sensitivity, maximum density and fog as compared with comparison, and was further exposed using a laser scanning exposure machine. It can be seen that the sensitivity and maximum density of the output image are extremely stable with respect to fluctuations in the oscillation wavelength.

Example 2
(Preparation of PET support)
Using terephthalic acid and ethylene glycol, PET 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. This was pelletized, dried at 130 ° C. for 4 hours, melted at 300 ° C., extruded from a T-die, and rapidly cooled to produce an unstretched film having a thickness of 175 μm after heat setting. 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 at 4 kg / cm 2 to obtain a roll having a thickness of 175 μm.

(Surface corona treatment)
Using a pisolid state corona treatment machine (manufactured by Pillar, 6KVA model), both sides of the support were treated at room temperature at 20 m / min. From the current and voltage readings at this time, it was found that the support was processed at 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 undercoat support)
(1) Preparation of undercoat layer coating solution Formulation (for photosensitive layer side undercoat layer)
Manufactured by Takamatsu Yushi Co., Ltd., pesresin A-515GB (30% by mass solution) 234 g
Polyethylene glycol monononyl phenyl ether (average ethylene oxide number = 8.5, 10% by mass solution) 21.5 g
Polymer fine particles (manufactured by Soken Chemical Co., Ltd., MP-1000, average particle size 0.4 μm)
0.91g
744 ml of distilled water
Formula (for back layer 1st layer)
Styrene-butadiene copolymer latex (solid content 40% by mass,
Styrene / butadiene mass ratio = 68/32) 158 g
2,4-dichloro-6-hydroxy-S-
Triazine sodium salt (8 mass% aqueous solution) 20g
Sodium laurylbenzenesulfonate (1% by weight aqueous solution) 10 ml
854 ml of distilled water
Formula (for back layer 2nd layer)
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, manufactured by Shin-Etsu Chemical Co., Ltd., Metroz TC-5 (2% by weight aqueous solution)
0.01 g of polymer fine particles (MP-1000, manufactured by Soken Chemical Co., Ltd.)
Sodium dodecylbenzenesulfonate (1% by weight aqueous solution) 10 ml
NaOH (1% by mass) 6 ml
Proxel (ICI) 1ml
805 ml of distilled water
(Preparation of undercoat support)
After both surfaces of the biaxially stretched polyethylene terephthalate support having a thickness of 175 μm were subjected to the corona discharge treatment, the undercoat coating solution formulation was applied to one surface (photosensitive layer surface) with a wire bar at a wet coating amount of 6.6 ml / Apply to m ² (per one side) and dry at 180 ° C. for 5 minutes, and then apply the above-mentioned undercoat coating liquid formulation to the back side (back side) with a wire bar to a wet coating amount of 5.7 ml / m ² . Then, it was dried at 180 ° C. for 5 minutes, and the above undercoat coating liquid formulation was applied to the back surface (back surface) with a wire bar so that the wet coating amount was 7.7 ml / m ^2. An undercoat support was prepared by drying for a minute.

(Preparation of back surface coating solution)
(Preparation of solid fine particle dispersion (a) of base precursor)
64 g of the base precursor compound 11, 28 g of diphenylsulfone and 10 g of surfactant demole N10 manufactured by Kao Corporation were mixed with 220 ml of distilled water, and the mixture was used with a sand mill (1/4 Gallon Sand Grinder Mill, manufactured by Imex Corporation). The beads were dispersed to obtain a solid fine particle dispersion (a) of a base precursor compound having an average particle size of 0.2 μm.

(Preparation of dye solid fine particle dispersion)
9.6 g of cyanine dye compound 13 and 5.8 g of sodium p-dodecylbenzenesulfonate were mixed with 305 ml of distilled water, and the mixture was dispersed in beads using a sand mill (1/4 Gallon sand grinder mill, manufactured by IMEX Co., Ltd.). Thus, a dye solid fine particle dispersion having an average particle size of 0.2 μm was obtained.

(Preparation of antihalation layer coating solution)
Gelatin 17 g, polyacrylamide 9.6 g, solid fine particle dispersion (a) 70 g of the above-mentioned precursor precursor, 56 g of the above dye solid fine particle dispersion, monodisperse polymethyl methacrylate fine particles (average particle size 8 μm, particle size standard deviation 0.4) 1.5 g, benzoisothiazolinone 0.03 g, polyethylene sulfonate 2.2 g, blue dye compound 14 0.2 g, yellow dye compound 15 3.9 g, and water 844 ml were mixed to form an antihalation layer coating solution. Prepared.

(Preparation of back surface protective layer coating solution)
The container was kept at 40 ° C., 50 g of gelatin, 0.2 g of sodium polystyrenesulfonate, 2.4 g of N, N-ethylenebis (vinylsulfoneacetamide), 1 g of sodium tert-octylphenoxyethoxyethanesulfonate, 30 mg of benzoisothiazolinone , Fluorine-based surfactant (F-1: N-perfluorooctylsulfonyl-N-propylalanine potassium salt) 37 mg, fluorine-based surfactant (F-2: polyethylene glycol mono (N-perfluorooctylsulfonyl-N-) Propyl-2-aminoethyl) ether [ethylene oxide average polymerization degree 15]) 0.15 g, fluorosurfactant (F-3) 64 mg, fluorosurfactant (F-4) 32 mg, acrylic acid / ethyl acrylate Copolymer (copolymerization mass ratio 5/95) .8G, Aerosol OT (manufactured by American Cyanamid Co.) 0.6 g, and the back surface protective layer coating liquid was 950ml mixing 1.8g, water and liquid paraffin emulsion as liquid paraffin.

<< Preparation of silver halide emulsion 1 >>
To a solution of 1421 ml of distilled water, 3.1 ml of a 1% by mass potassium bromide solution was added, and a solution containing 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 10.8 ml of a 10% by mass aqueous solution of benzimidazole 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 a precipitation / desalting / water washing step was 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 mol per mol of silver, and further 5 minutes later, tellurium sensitizer B was added in a methanol solution to a ratio of 2. 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 1 was prepared.

  The grains in the prepared silver halide emulsion were silver iodobromide grains 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 2 >>
In the preparation of silver halide emulsion 1, the liquid temperature at the time of grain formation was changed from 30 ° C. to 47 ° C., and solution B was changed to diluting 15.9 g of potassium bromide with distilled water to a volume of 97.4 ml, Solution D was changed to diluting 45.8 g of potassium bromide with distilled water to a volume of 400 ml, and the addition time of solution C was changed to 30 minutes to remove potassium hexacyanoiron (II) in the same manner. A silver halide emulsion 2 was prepared. Precipitation / desalting / washing / dispersion was carried out in the same manner as silver halide emulsion 1. Furthermore, the addition amount of the 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 ⁻⁴ mol as the total of the sensitizing dye A and the sensitizing dye B per mol of silver. The amount of tellurium sensitizer B added is 1.1 × 10 ⁻⁴ mol per mol of silver, and 1-phenyl-2-heptyl-5-mercapto-1,3,4-triazole is added to 3 mol per mol of silver. Spectral sensitization, chemical sensitization, 5-methyl-2-mercaptobenzimidazole, and 1-phenyl-2-heptyl-5-mercapto in the same manner as silver halide emulsion 1 except that the amount was changed to 3 × 10 ⁻³ mol. -1,3,4-Triazole was added to obtain a silver halide emulsion 2. The emulsion grains of the silver halide emulsion 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 >>
In the preparation of silver halide emulsion 1, silver halide emulsion 3 was prepared in the same manner except that the liquid temperature at the time of grain formation was changed from 30 ° C. to 27 ° C. Further, precipitation / desalting / washing / dispersion was performed in the same manner as silver halide emulsion 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. ^A silver halide emulsion 3 was obtained in the same manner as silver halide emulsion 1 except that ³ mol and the addition amount of tellurium sensitizer B were changed to 5.2 × 10 ⁻⁴ mol per mol of silver. The emulsion grains of the silver halide emulsion 3 were silver iodobromide grains 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 mixed emulsion A for coating solution >>
70% by weight of silver halide emulsion 1, 15% by weight of silver halide emulsion 2 and 15% by weight of silver halide emulsion 3 were dissolved, and 7% by mole of silver in a 1% by weight aqueous solution of benzothiazolium iodide. × 10 ^-3 mol was added. Further, water was added so that the content of silver halide per 1 kg of the mixed emulsion for coating solution was 38.2 g as silver. This is designated as mixed emulsion A for coating solution.

<< Preparation of fatty acid silver dispersion >>
Henkel behenic acid (product name Edenor C22-85R) 87.6 kg, distilled water 423 L, 5 mol / L NaOH aqueous solution 49.2 L, tert-butanol 120 L were mixed and stirred at 75 ° C. for 1 hour to react. A sodium behenate solution was obtained. 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 tert-butanol was kept at 30 ° C., and with sufficient stirring, the total amount of the previous sodium behenate solution and the total amount of silver nitrate aqueous solution were 93 minutes and 15 seconds at a constant flow rate, respectively. 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 aqueous silver nitrate solution, and then the addition of the sodium behenate solution is started. After the addition of the aqueous silver nitrate solution, only the sodium behenate solution is added for 14 minutes and 15 seconds. It was made to be. 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 aging, the solid content was separated by centrifugal filtration, and the solid content was washed with water until the conductivity of filtered 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 microscopic photography, it was a scaly crystal having an average aspect ratio of 5.2, an average sphere equivalent diameter of 0.52 μm, and a sphere equivalent diameter variation coefficient of 15%. .

19.3 kg of polyvinyl alcohol (PVA-217, manufactured by Kuraray Co., Ltd.) and water are added to a wet cake corresponding to a dry solid content of 260 kg, and the whole amount is made 1000 kg, and then slurried with a dissolver blade. Pre-dispersed by Mizuho Kogyo, PM-10 type). Next, the pre-dispersed stock solution is adjusted to 1260 kg / cm ² by adjusting the pressure of the disperser (trade name: Microfluidizer M-610, manufactured by Microfluidics International Corporation, using Z-type interaction chamber) three times. Treatment gave 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 >>
16 kg of water was added to 10 kg of a 20% by mass aqueous solution of a silver ion reducing agent (compounds and amounts shown in Table 3) and 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 in a horizontal bead mill (IMM Co., Ltd., UVM-2) 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-1 dispersion. The reducing agent particles contained in the reducing agent dispersion thus obtained had a median diameter of 0.42 μm and a maximum particle diameter of 2.0 μm or less. The obtained reducing agent 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 dispersion of yellow color developing leuco dye and cyan color developing leuco dye >>
Yellow chromogenic leuco dye (compounds and amounts shown in Table 3) and cyan chromogenic leuco dye (compounds and amounts shown in Table 3) and modified polyvinyl alcohol (Kuraray Co., Ltd., 10% by weight of Poval MP-203) 75 g of water was added to 150 g of an aqueous solution and mixed well to obtain a slurry. This slurry was dispersed with a 0.5 mm zirconia bead and a sand mill (1/4 Gallon sand grinder mill, manufactured by IMEX Co., Ltd.) for 10 hours at a rotation speed of 1500 rpm to obtain a solid fine particle dispersion having a median diameter of 0.4 μm. Obtained. The obtained 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 dispersion of development accelerator-1 >>
75 g of water was added to 75 g of a development accelerator-1 and 150 g of a 10% by weight aqueous solution of modified polyvinyl alcohol (Kuraray Co., Ltd., Poval MP-203) and mixed well to obtain a slurry. Using a 0.5 mm zirconia bead and a sand mill (1/4 Gallon sand grinder mill, manufactured by AIMEX Co., Ltd.), this slurry was dispersed with beads at a rotation speed of 1500 rpm for 10 hours to obtain a solid fine particle dispersion having a median diameter of 0.35 μm. Obtained. The obtained 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-2 dispersion >>
10 kg of water was added to 10 kg of a 10 wt% aqueous solution of hydrogen bonding compound-2 (tri (4-tert-butylphenyl) phosphine oxide) and denatured polyvinyl alcohol (Kuraray Co., Ltd., Poval MP203). Mix to make a slurry. This slurry was fed with a diaphragm pump and dispersed in a horizontal bead mill (IMM Co., Ltd., UVM-2) 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 22% by mass to obtain a hydrogen bonding compound-2 dispersion. The reducing agent particles contained in the reducing agent 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 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 organic polyhalogen compound-1 dispersion >>
10 kg of an organic polyhalogen compound-1 (2-tribromomethanesulfonyl naphthalene), 10 kg of a 20 wt% aqueous solution of modified polyvinyl alcohol (Kuraray Co., Ltd., Poval MP203), and a 20 wt% aqueous solution of sodium triisopropyl naphthalenesulfonate 0 4 kg and 16 kg of water were added and mixed well to obtain a slurry. This slurry was fed with a diaphragm pump and dispersed for 5 hours in a horizontal bead mill filled with zirconia beads having an average diameter of 0.5 mm (manufactured by Imex Co., Ltd., UVM-2), and then benzoisothiazolinone sodium salt 0. 2 g and water were added to prepare an organic polyhalogen compound concentration of 23.5% by mass to obtain an organic polyhalogen compound-1 dispersion. The organic polyhalogen compound particles contained in the polyhalogen compound dispersion thus obtained had a median diameter of 0.36 μm and a maximum particle diameter of 2.0 μm or less. The obtained organic polyhalogen compound 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 organic polyhalogen compound-2 (tribromomethanesulfonylbenzene), 10 kg of 20 wt% aqueous solution of modified polyvinyl alcohol (Kuraray Co., Ltd., Poval MP203), 0.4 kg of 20 wt% 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 bead mill filled with zirconia beads having an average diameter of 0.5 mm (manufactured by Imex Co., Ltd., UVM-2), and then benzoisothiazolinone sodium salt 0. 2 g and water were added to prepare an organic polyhalogen compound concentration of 26% by mass to obtain an organic polyhalogen compound-2 dispersion. The organic polyhalogen compound particles contained in the polyhalogen compound dispersion thus obtained had a median diameter of 0.41 μm and a maximum particle diameter of 2.0 μm or less. The obtained organic polyhalogen compound 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 Phthalazine Compound-1 Solution >>
8 kg of modified polyvinyl alcohol (manufactured by Kuraray Co., Ltd., MP203) was dissolved in 174.57 kg of water, and then 3.15 kg of a 20 mass% aqueous solution of sodium triisopropylnaphthalenesulfonate and phthalazine compound-1 (6-isopropylphthalazine) Was added to prepare a 5% by mass solution of phthalazine compound-1.

<< 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% by mass aqueous solution.

<< Preparation of Pigment-1 Dispersion >>
C. I. Pigment Blue 60 (64 g) and Kao Corp. demole N (6.4 g) were added to 250 g of water 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 dispersion thus obtained had an average particle size of 0.21 μm.

<< Preparation of SBR Latex Liquid >>
An SBR latex having a Tg of 23 ° C. was prepared as follows.

Ammonium persulfate is used as a polymerization initiator, an anionic surfactant is used as an emulsifier, 70.5 parts by mass of styrene, 26.5 parts by mass of butadiene and 3 parts by mass of acrylic acid are subjected to emulsion polymerization, and then aging is performed at 80 ° C. for 8 hours. went. 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.

(SBR latex: -St (70.5) -Bu (26.5) -AA (3) -latex) Tg23 ° C
Average particle size 0.1 μm, concentration 43% by mass, equilibrium moisture content 0.6% by mass at 25 ° C. and relative humidity 60%, ion conductivity 4.2 mS / cm (measurement of ion conductivity is made by Toa Denpa Kogyo Co., Ltd.) Conductivity meter CM-30S was used, latex stock solution (43% by mass) measured at 25 ° C.), pH 8.4
SBR latexes having different Tg were prepared in the same manner by appropriately changing the ratio of styrene and butadiene.

<< Preparation of emulsion layer (photosensitive layer) coating solution >>
1000 g of the fatty acid silver dispersion obtained above, 125 ml of water, 204 g of the reducing agent dispersion, a dispersion of yellow chromophoric leuco dye and cyan chromophoric leuco dye (type and amount are listed in Table 3), 27 g of pigment-1 dispersion , 82 g of organic polyhalogen compound-1 dispersion, 40 g of organic polyhalogen compound-2 dispersion, 173 g of phthalazine compound-1 solution, 1082 g of SBR latex (Tg: 20.5 ° C.) solution, and 9 g of mercapto compound-1 aqueous solution are sequentially added. Immediately before coating, 158 g of mixed emulsion A for coating solution was added and mixed well, and the emulsion layer coating solution was directly fed to the coating die and coated. The viscosity of the emulsion layer coating solution was 40 [mPa · s] at 40 ° C. (No. 1 rotor, 60 rpm) as measured with a B-type viscometer of Tokyo Keiki. The viscosity of the coating solution at 25 ° C. using an RFS fluid spectrometer manufactured by Rheometrics Far East Co., Ltd. is 1500, 220, 70 at shear rates of 0.1, 1, 10, 100, and 1000 [1 / second], respectively. 40 and 20 [mPa · s].

<Preparation of emulsion surface intermediate layer coating solution>
772 g of 10% by weight aqueous solution of polyvinyl alcohol PVA-205 (manufactured by Kuraray Co., Ltd.), 5.3 g of 20% by weight dispersion of pigment, methyl methacrylate / styrene / butyl acrylate / hydroxyethyl methacrylate / acrylic acid copolymer (copolymerization) Mass ratio 64/9/20/5/2) 2 ml of aerosol OT (manufactured by American Cyanamid Co., Ltd.) 226 g of 27.5 mass% latex 2 ml, 20 mass% aqueous solution of diammonium phthalate 10.5 ml, water was added to a total amount of 880 g, and the pH was adjusted to 7.5 with NaOH to prepare an intermediate layer coating solution, which was fed to the coating die so as to be 10 ml / m 2. The viscosity of the coating solution was 21 [mPa · s] at a B-type viscometer of 40 ° C. (No. 1 rotor, 60 rpm).

<< Preparation of emulsion surface protective layer first layer coating solution >>
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 17 [mPa · s] at 40 ° C. (No. 1 rotor, 60 rpm) B-type viscometer.

<< Preparation of photothermographic material >>
On the back surface side of the undercoat support, the antihalation layer coating solution is applied so that the solid 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 1. A simultaneous multilayer coating was applied so as to be 7 g / m ² , followed by drying to produce a back layer. A photothermographic material sample was prepared on the surface opposite to the back surface by simultaneous multi-layer coating using the slide bead coating method in the order of the emulsion layer, intermediate layer, protective layer first layer, and protective layer second layer from the undercoat surface. . At this time, the emulsion layer and the intermediate layer were adjusted to 31 ° C., and the protective layer first layer was adjusted to 36 ° C. The coating amount (g / m ² ) of each compound in the emulsion layer is as follows.

Silver behenate 6.19
Reducing agent Types and amounts are listed in Table 3. Yellow color forming leuco dyes and cyan color forming leuco dyes Types and amounts are listed in Table 3. Pigment (CI Pigment Blue 60) 0.032
Polyhalogen compound-1 0.46
Polyhalogen compound-2 0.25
Phthalazine Compound-1 0.21
SBR latex 11.1
Mercapto Compound-1 0.002
Silver halide (as Ag) 0.145
The coating and drying conditions 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 a wind at a dry bulb temperature of 10 to 20 ° C., it is transported in a non-contact type, and is 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 a relative humidity of 40 to 60%, and then the film surface was heated to 70 to 90 ° C. After heating, the film surface was cooled to 25 ° C. The photothermographic material thus prepared had a Beck smoothness of 550 seconds on the photosensitive layer surface side and 130 seconds on the back surface. Further, the pH of the film surface on the photosensitive layer surface side was measured and found to be 6.0.

(Evaluation of photographic performance)
Photographic materials were exposed with a Fuji Medical Dry Laser Imager FM-DP L (with a 660 nm semiconductor laser with a maximum output of 60 mW (IIIB)). After exposure, the FM-DPL thermal development unit is remodeled and thermally developed (total of 24 seconds with 4 panel heaters set at 112 ° C-119 ° C-121 ° C-121 ° C = standard development time is 24 seconds) did. For each image obtained by exposure at each wavelength, density measurement is performed with a Macbeth densitometer (TD-904), and a characteristic curve composed of the horizontal axis; exposure amount, vertical axis: image density is created, and more than the unexposed portion. The reciprocal of the exposure ratio required to give 1.0 high density was defined as sensitivity, and the minimum density (fogging) was further measured. The sensitivity is expressed as a relative value with the sensitivity of the sample 201 in Table 3 as 100.

<Measurement of hue angle hab>
The hue angle hab is measured with a spectrocolorimeter CM− in a 2 ° field of view using the minimum light density portion and the optical density 1.0 portion of the developed sample as the light source for color measurement defined by the CIE. It was determined by measurement using 508d (Minolta).

<Image preservation>
(Evaluation of image storability of minimum density area)
Each of the heat-developed samples prepared in the same manner as the above-described sensitivity, fog, and maximum density measurement methods was subjected to a commercially available white fluorescent lamp with an illuminance of 500 lux on the sample surface in an environment of 45 ° C. and 55% RH. And then irradiated continuously for 3 days. Measure the minimum concentration (D ₂ ) of the sample irradiated with the fluorescent lamp and the minimum concentration (D ₁ ) of the sample not irradiated with the fluorescent lamp, and calculate the minimum density change rate (%) from the following formula. A measure of image preservation. The closer the value is to 100, the better.

Minimum density change rate = D ₂ / D ₁ × 100 (%)
(Evaluation of image storage stability at the highest density area)
Each 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 change in the maximum density is measured. It was measured and used as a measure of image preservation at the highest density part. The closer the value is to 100, the better.

Image density change rate = maximum density of sample stored at 45 ° C./maximum density of sample stored at 25 ° C. × 100 (%)
<Measurement of hue angle hab after image storage>
Each sample was placed in a 45 ° C., 55% RH environment with a commercially available white fluorescent lamp so that the illuminance on the sample surface was 500 lux, and irradiated continuously for 3 days. The .0 portion was determined by measuring with a spectrocolorimeter CM-508d (manufactured by Minolta Co., Ltd.) in a 2 ° field of view using the common light source D65 defined by CIE as the light source for colorimetry.

  The results are shown in Table 4.

  From the results shown in Table 4, it can be seen that the photothermographic material of the present invention has higher sensitivity, lower fog and good color tone than the comparative sample. Further, it can be seen that the image storage stability is much superior to that of the comparative example.

  In the sample of the present invention, the highest image density and fog deterioration due to the action of light and heat during storage are very small, and the hue angle hab defined by CIE still exceeds 180 ° after image storage and It was found that the angle was less than 270 °, had a cool image tone, the image color tone deteriorated significantly with respect to light and heat, and an appropriate output image was obtained as a diagnostic image.

Claims (9)

In a silver salt photothermographic imaging material having an image forming layer containing a non-photosensitive organic silver salt, silver halide, a silver ion reducing agent and a binder on a support, at least one kind of the silver ion reducing agent is represented by the following general formula: A compound represented by the formula (1), comprising a yellow color-forming leuco dye and a cyan color-forming leuco dye on the side having the image forming layer, and the yellow color-forming leuco dye and the general formula (1) The addition ratio of the compounds represented (number of moles of the yellow color-forming leuco dye / number of moles of the compound represented by formula (1)) is 0.001 to 0.2, and the cyan color-forming leuco dye And the addition ratio of the compound represented by the general formula (1) (number of moles of the cyan color-forming leuco dye / number of moles of the compound represented by the general formula (1)) is 0.001 to 0.5. Silver salt photothermography Imaging material.

(Wherein R ₁₁ and R ₁₂ each independently represents a hydrogen atom, an aliphatic group or an aromatic group. R ₁₃ and R ₁₄ each independently represent a hydrogen atom, an aliphatic group, an aromatic group or a heterocyclic ring) Q represents a substitutable group on the benzene ring, and n represents an integer of 0 to 2. When Q is plural, each Q may be the same or different. The addition ratio of the yellow color-forming leuco dye and the compound represented by the general formula (1) (the number of moles of the yellow color-forming leuco dye / the number of moles of the compound represented by the general formula (1)) is 0.001. The silver salt photothermographic imaging material according to claim 1, wherein the silver salt photothermographic imaging material is .about.0.1. The addition ratio of the cyan color-forming leuco dye and the compound represented by the general formula (1) (the number of moles of the cyan color-forming leuco dye / the number of moles of the compound represented by the general formula (1)) is 0.001. The silver salt photothermographic imaging material according to claim 1, wherein the silver salt photothermographic imaging material is .about.0.3. The silver salt photothermographic imaging material according to any one of claims 1 to 3, wherein the yellow color-forming leuco dye is a compound represented by the following general formula (2).

(In the formula, R ₁ represents an alkyl group or a cycloalkyl group, R ₂ represents a hydrogen atom, an alkyl group, a cycloalkyl group, or an acylamino group, provided that R ₁ and R ₂ are 2-hydroxyphenylmethyl groups. R ₃ represents a hydrogen atom, an alkyl group or a cycloalkyl group, and R ₄ represents a substituent which can be substituted on the benzene ring. The silver salt photothermographic imaging material according to any one of claims 1 to 3, wherein the yellow color-forming leuco dye is a compound represented by the following general formula (3).

(In the formula, R ₃₁ , R ₃₂ , R ₃₃ and R ₃₄ each independently represents an alkyl group or cycloalkyl group having 1 to 20 carbon atoms. R ₃₅ represents a hydrogen atom, an aliphatic group, an aromatic group or a hetero group. Represents a cyclic group.) The silver salt photothermographic imaging material according to any one of claims 1 to 3, wherein the cyan color-forming leuco dye is a compound represented by the following general formula (CL).

(Wherein R _c1 and R _c2 are a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, alkenyl group, alkoxy group, —NHCO—R _c6 group (R _c6 is an alkyl group, aryl group, heterocyclic group) Or R _c1 and R _c2 represent a group which is bonded to each other to form an aliphatic hydrocarbon ring, an aromatic hydrocarbon ring or a heterocyclic ring, and A _c represents a —NHCO— group, —CONH -. a group or a -NHCONH- group, a where R _c3 substituted or unsubstituted, alkyl group, aryl group or heterocyclic group also, -A _c -R _c3 may be of a hydrogen atom .W _c Is a hydrogen atom or —CONH—R _c5 group, —CO—R _c7 group or —CO—O—R _c7 group (R _c7 represents a substituted or unsubstituted alkyl group, aryl group or heterocyclic group). represents, R _c4 is a hydrogen atom, a halogen atom, a substituted or unsubstituted , Alkyl group, alkenyl group, alkoxy group, a carbamoyl group or a nitrile group,, R _c5 is -CONH-R _c8 group, -CO-R _c8 group or -CO-O-R _c8 group (R _c8 is a substituted or Represents an unsubstituted alkyl group, aryl group, or heterocyclic group.), And X _c represents a substituted or unsubstituted aryl group or heterocyclic group.) The silver salt photothermographic imaging material according to claim 1, wherein the silver halide is infrared sensitized. The silver salt photothermographic imaging material according to any one of claims 1 to 7, further comprising at least one selected from a heteroaromatic mercapto compound and a heteroaromatic disulfide compound. The hue angle hab of the silver salt photothermographic imaging material after thermally developing the silver salt photothermographic imaging material according to any one of claims 1 to 8, wherein 180 ° <hab <270 °. An image forming method.