JP2004102263A - Silver salt photothermographic dry imaging material and its image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a silver salt photothermographic dry imaging material which has high density, which is little decreased in the density with time and no fog in any time before and after heat development, which is free from irregular density when the material is processed in a heat developing device, and which is improved in the carrying property, and to provide an image forming apparatus using the above silver salt photothermographic dry imaging material. <P>SOLUTION: The silver salt photothermographic dry imaging material has at least one layer of a photosensitive layer containing a photosensitive emulsion containing non photosensitive organic silver salt particles and photosensitive silver halide particles, a reducing agent for silver ion, and a binder on a support. The dry imaging material contains at least one kind of compound expressed by general formula (A-1) and at least one kind of compound expressed by general formula (A-2). <P>COPYRIGHT: (C)2004,JPO

Description

The present invention relates to a silver salt photothermographic dry imaging material and an image forming apparatus using the silver salt photothermographic dry imaging material. A silver salt photothermographic dry imaging material which has a small decrease in density over time, has no fog, and has an improved density unevenness when processed by a heat development processing apparatus; and The present invention relates to an image forming apparatus.

Conventionally, in the fields of medical treatment and printing plate making, waste liquids caused by wet processing of image forming materials have been a problem in terms of workability.In recent years, it has been strongly desired to reduce the amount of treated waste liquids from the viewpoint of environmental conservation and space saving. It is rare. Therefore, a silver salt photothermographic dry imaging material capable of forming an image only by applying heat has been put to practical use, and is rapidly spreading in the above-mentioned fields.

Silver salt photothermographic dry imaging materials (hereinafter, also simply referred to as thermal developing materials or photosensitive materials) themselves have been proposed for a long time, and are described, for example, in US Pat. Nos. 3,152,904 and 3,457,075. , D. "Dry Silver Photographic Material" by Morgan, or D.M. H. "Thermally Processed Silver Systems" by Klosterboer, Imaging Processes and Materials (Nebulette), 8th Edition, St. Georg, 8th Edition, Imaging Processes and Materials. Walworth, edited by A. Shepp, p. 279, 1989).

This heat development material is processed by a heat development processing apparatus which forms an image by applying stable heat to a heat development material usually called a heat development processor. As described above, with the rapid spread in recent years, a large amount of this thermal development processing apparatus has been supplied to the market.

近年 Furthermore, in recent years, there has been a demand for a compact laser imager and quick processing. For this purpose, the heat developing section is rotated and conveyed while being in close contact with the surface of the heat drum, a method in which a recording material is conveyed while being pressed against the surface of a plate heater by a pressing roller or the like, and heat development is performed. Various methods have been proposed, such as a method in which a plurality of pairs of rollers are arranged, and the pair of rollers is rotated to pinch and convey the heat development material therebetween to process the heat development material. However, all of them have a problem that they are easily affected by the temperature variation of the heat developing section, and the development is likely to be uneven or the conveyance failure is apt to occur.

Also, since thermal development is performed at a temperature of 100 ° C. or higher, the temperature of the thermal development material immediately after thermal development is also high, and cooling at high speed is important for speeding up. To cope with such a problem, a cooling method is disclosed in Patent Document 1 (Japanese Patent Laid-Open No. 3-208048). However, in this method, the density unevenness becomes severe, and a conveyance failure occurs. There was a problem that value was significantly impaired. Further, it became clear that the difference in the cooling process after the development caused a large change in density over time after the heat development.
JP-A-3-208048

The present invention has been made in view of the above problems, and has an object to provide a high-density silver halide photothermographic dry imaging material whose density decreases with time both before and after thermal development. A small silver halide photothermographic dry imaging material with improved transportability, no fogging, no density unevenness when processed by a thermal development processor, and an image forming apparatus using the silver salt photothermographic dry imaging material. To provide.

Another object of the present invention is to provide a high-quality silver salt photothermographic dry imaging material having excellent silver image stability after thermal development even when processed rapidly, and an image forming apparatus using the same.

The present inventors have conducted intensive studies and found that silver halide photothermographic dry imaging materials that can respond to rapid processing, have good storage stability before thermal development, have excellent silver image stability after thermal development, and have high image quality Have been developed, which has led to the present invention.

That is, the object of the present invention is achieved by adopting any of the following configurations.
(Claim 1)
Silver salt photothermographic dry imaging material having at least one photosensitive layer containing a photosensitive emulsion containing non-photosensitive organic silver salt particles and photosensitive silver halide particles, a silver ion reducing agent, and a binder on a support Wherein the silver salt photothermographic dry imaging material comprises at least one compound represented by the following general formula (A-1) and at least one compound represented by the following general formula (A-2).

(In the formula, X ₁ and X ₂ each represent a hydrogen atom, a halogen atom, an alkyl group, a cycloalkyl group, an alkenyl group, a cycloalkenyl group, an aryl group, a heterocyclic group, or a divalent linking group and a bond via this; And a group represented by —COO [1 / K (M)], wherein M represents a hydrogen atom or a K-valent cation, and X ₁ and X ₂ at least one is a group represented by -COO [1 / K (M)] .R ^1, R ^2, R ³ are each a hydrogen atom, a halogen atom, an alkyl group, a cycloalkyl group, an alkenyl group, a cycloalkenyl Group, an aryl group, a heterocyclic group, or a divalent linking group, and a group consisting of an aryl group and a heterocyclic group bonded via the divalent linking group. May be formed.)

(Wherein, Z represents a —S— group or —C (R ₃₃ ) (R ₃₃ ′) —, and R ₃₃ and R ₃₃ ′ represent a hydrogen atom or a substituent. R ₃₁ , R ₃₂ , and R ₃₁ 'And R ₃₂ ' represent a substituent, and X ₃₁ and X ₃₁ 'represent a hydrogen atom or a substituent.)
(Claim 2)
2. The silver salt photothermographic dry imaging material according to claim 1, wherein the heat-transition temperature of the photosensitive layer after development processing at a temperature of 100 to 200 ° C. is 46 to 200 ° C.
(Claim 3)
The silver salt photothermographic dry imaging material according to claim 1 or 2, wherein the non-photosensitive organic silver salt particles contain 70 to 99% by mass of silver behenate.
(Claim 4)
4. The photosensitive layer according to claim 1, wherein at least one of the photosensitive layer and the layer provided adjacent to the photosensitive layer contains at least one compound containing a vinyl sulfone group. Item 13. The silver salt photothermographic dry imaging material according to item 1.
(Claim 5)
The compound according to any one of claims 1 to 4, wherein at least one of the photosensitive layer and a layer provided adjacent to the photosensitive layer contains a compound represented by Formula (A-3). 4. The silver salt photothermographic dry imaging material according to claim 1.

General formula (A-3)
Z-SO ₂ -SM
(In the formula, Z represents a substituted or unsubstituted alkyl group, aryl group or heterocyclic group, and M represents a metal atom or an organic cation.)
(Claim 6)
The silver salt photothermographic dry imaging material according to any one of claims 1 to 5, wherein the silver ion reducing agent is represented by a compound represented by the following general formula (A-4).

(Wherein, R ₁₁ and R ₁₂ each independently represent a hydrogen atom, a 3- to 10-membered non-aromatic cyclic group, or a 5- to 6-membered aromatic cyclic group, provided that R ₁₁ and R ₁₂ are simultaneously a hydrogen atom R ₁₃ and R ₁₄ each independently represent a hydrogen atom, an alkyl group, a cycloalkyl group, an alkenyl group, a cycloalkenyl group, an aryl group or a heterocyclic group, and Q represents a substituent on a benzene ring. Represents a group, and n represents an integer of 0 to 2. When Q is plural, each Q may be the same or different.)
(Claim 7)
An image forming apparatus for subjecting the silver salt photothermographic dry imaging material according to any one of claims 1 to 6 to image exposure and heat development processing, wherein a portion between a supply part of the silver salt photothermographic dry imaging material and an image exposure part is provided. An image forming apparatus, wherein the conveying speed of the image forming apparatus is set to 20 to 200 mm / sec.

According to the present invention, the silver halide photothermographic dry imaging material having a high density has a small density decrease over time before and after thermal development of the silver salt photothermographic dry imaging material, and does not cause fogging. The present invention can provide a silver salt photothermographic dry imaging material having improved transportability, and an image forming apparatus using the silver salt photothermographic dry imaging material.

Hereinafter, the present invention will be described in detail.

<< The compound of the general formula (A-1) of the present invention will be described.

The group represented by X ₁ and X ₂ in the compound of the general formula (A-1) is a hydrogen atom, a halogen atom, an alkyl group, a cycloalkyl group, an alkenyl group, a cycloalkenyl group, an aryl group or a heterocyclic group, A group consisting of a valent linking group, an aryl group and a heterocyclic group bonded through the valence linking group, and a group represented by —COO [1 / K (M)], wherein M is a hydrogen atom or K It represents a valent cation, and at least one of the groups represented by X ₁ and X ₂ is the carboxyl group represented by —COO [1 / K (M)]. R ¹ , R ² , and R ^{3 each} include a hydrogen atom, a halogen atom, an alkyl group (including alkenyl group), an aryl group or a heterocyclic group, a divalent linking group, and an aryl group or a heterocyclic group bonded thereto. Represents a group, which may be different or the same. In particular, it is preferable that any one of R ^{1 to} R ³ is bonded to an aryl group or a heterocyclic group via a divalent linking group.

Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.

The alkyl group may be linear, branched or cyclic, and preferably has 1 to 30 carbon atoms.For example, as a methyl group, an ethyl group, a propyl group, a butyl group, an octyl group, a dodecyl group, and a cycloalkyl group, And cyclohexyl group.

The alkenyl group is preferably straight-chain, branched or cyclic and has 2 to 30 carbon atoms, and examples thereof include a propenyl group, a butenyl group and a nonenyl group.

Examples of the aryl group include a phenyl group and a naphthyl group, which may have a substituent.Examples of the substituent include groups such as a halogen atom, an alkyl group, a sulfonyl group, an amide group, and a carboxyl group. can give.

Examples of the heterocyclic group include a tetrahydropyranyl group, a pyridyl group, a furyl group, a thienyl group, an imidazolyl group, a thiazolyl group, a thiadiazolyl group, and an oxadiazolyl group. The heterocyclic group may have a substituent, and the substituent preferably contains at least one electron-withdrawing group.

化合物 The amount of the compound represented by formula (A-1) is preferably 0.001 mol to 1 mol, particularly preferably 0.001 mol to 0.25 mol, per 1 mol of silver.

The following are typical examples of typical compounds.

Next, the compound represented by formula (A-2) of the present invention will be described.

In bisphenol compound represented by the general formula (A-2), Z is -S- group or _{-C (R 33) (R 33} ') - represents a group, R _33, R _33' is hydrogen atom or a substituent Represents Examples of the substituent represented by R ₃₃ and R ₃₃ ′ include an alkyl group, (each group such as methyl, ethyl, propyl, isopropyl, cyclopropyl, butyl, isobutyl, sec-butyl, t-butyl), cycloalkyl Alkyl group (each group such as cyclohexyl, 1-methyl-cyclohexyl), alkenyl group (each group such as vinyl, propenyl, butenyl, pentenyl, isohexenyl, butenylidene, isopentylidene), cycloalkenyl group (group such as cyclohexenyl) ), An alkynyl group (each group such as ethynyl, propynylidene, etc.), an aryl group (each group such as phenyl and naphthyl), a heterocyclic group (each group such as furyl, thienyl, pyridyl, tetrahydrofuranyl), halogen, hydroxyl , Alkoxy, aryloxy, acyloxy, sulfonyloxy, nitro , Amino, acylamino, sulfonylamino, sulfonyl, carboxy, alkoxycarbonyl, aryloxycarbonyl, carbamoyl, sulfamoyl, cyano, each group sulfo and the like. R ₃₃ and R ₃₃ ′ are preferably a hydrogen atom or an alkyl group.

R ₃₁ , R ₃₂ , R ₃₁ ′, and R ₃₂ ′ each represent a substituent, and examples of the substituent include the same groups as those described above for R ₃₃ and R ₃₃ ′.

R ₃₁ , R ₃₂ , R ₃₁ ′, and R ₃₂ ′ are preferably an alkyl group, a cycloalkyl group, an alkenyl group, a cycloalkenyl group, an alkynyl group, an aryl group, a heterocyclic group, etc., and an alkyl group is more preferable. .

Examples of the substituent on the alkyl group include the same groups as those described above for R ₃₃ and R ₃₃ ′.

R ₃₁ , R ₃₂ , R ₃₁ ′ and R ₃₂ ′ are more preferably tertiary alkyl groups such as t-butyl, t-amyl, t-octyl and 1-methylcyclohexyl.

X ₃₁ and X ₃₁ ′ represent a hydrogen atom or a substituent, and examples of the substituent include the same groups as those described in the description of R ₃₃ and R ₃₃ ′.

具体 Specific examples of the bisphenol compound represented by the general formula (A-2) are shown below, but the present invention is not limited thereto.

As a method for adding the compounds represented by the general formulas (A-1) and (A-2), the compound is dispersed in water or dissolved in an organic solvent to prepare a coating solution for a photosensitive layer or a coating solution for an adjacent layer. It can be contained in these layers. As the organic solvent, alcohols such as methanol and ethanol, ketones such as acetone and methyl ethyl ketone, and aromatic solvents such as toluene and xylene can be arbitrarily selected.

The amount of the compound represented by the general formula (A-2) is suitably in the range of 1 × 10 ^-2 to 10 mol, preferably 1 × 10 ^{-2 to} 1.5 mol per mol of silver. .

The addition molar ratio of the compound represented by the general formula (A-1) to the compound represented by the general formula (A-2) (general formula (A-1) / general formula (A-2)) is , 0.001 to 1.0, and preferably 0.005 to 0.5.

Next, the compound containing a vinyl sulfone group of the present invention will be described.

ビ ニ ル As the compound containing a vinyl sulfone group used in the present invention, a compound represented by the following general formula (A-5) is preferable.

General formula (A-5)
(R ₁ R ₂ C = CR ₃ -SO ₂ ) n- [L]
In the formula, R ₁ , R ₂ , and R ₃ represent a hydrogen atom, an alkyl group, or an aryl group, and in these substituents, adjacent groups may form a ring. n represents 1, 2, 3, or 4, and L represents an n-valent group. As the n-valent group, for example, a monovalent, divalent or higher valent linking group composed of a residue having a bond at an arbitrary position of a compound such as an alkane, alkene, or aromatic hydrocarbon ring having 20 or less carbon atoms Further, for example, a divalent or higher valent linking group having a plurality of bonds at arbitrary positions of an alkyl-substituted aromatic hydrocarbon ring known variously in this field may be used.

The aromatic hydrocarbon ring may have a substituent selected from the group consisting of halogen (eg, Br, Cl), hydroxy, amino, carboxy, alkyl, and alkoxy. Examples of the compound containing a vinyl sulfone group according to the present invention are listed below, but the present invention is not limited thereto.

Compounds containing a vinyl sulfone group are described in the literature, for example, U.S. Pat. Nos. 2,994,611, 3,061,436, 3,132,945, 3,490,911 and 3,490,911. No. 3,527,807, No. 3,593,644, No. 3,642,486, No. 3,642,908, No. 3,839,042, No. 3,841, Nos. 872, 3,957,882, 4,088,495, 4,108,848, 4,137,082, and 4,142,897. It is. These are also described in Belgian Patent 819,015 and U.S. Pat. No. 4,173,481.

The compound containing a vinyl sulfone group is generally used in an amount of at least 0.001 mol per mol of silver. Usually, the range is from 0.01 to 5 mol per mol of silver, preferably from 0.02 to 0.6 mol per mol of silver.

化合物 The compound of the formula (A-3) used in the present invention will be described.

General formula (A-3)
Z-SO ₂ -SM
In the general formula (A-3), Z represents an aliphatic hydrocarbon group, an aryl group, or a heterocyclic group, and M represents a cation.

The aliphatic hydrocarbon group represented by Z in the formula (A-3) is a linear, branched or cyclic alkyl group (preferably having 1 to 20, more preferably 1 to 12, and particularly preferably 1 to 8 carbon atoms). And, for example, methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, sec-butyl, tert-butyl, n-octyl, iso-amyl, tert-amyl, hexyl, dodecyl, octadecyl , Cyclohexyl, etc.), an alkenyl group (preferably having 2 to 20, more preferably 2 to 12, particularly preferably 2 to 8, for example, vinyl, allyl, 2-butenyl, 3-pentel, etc.) Alkynyl group (preferably having 2 to 20 carbon atoms, more preferably 2 to 12 carbon atoms, and particularly preferably 2 to 8 carbon atoms. Roparugiru group, 3-pentynyl group.), Etc. can be applied, which may have a substituent. As the substituent, for example, an aryl group (preferably having 6 to 30 carbon atoms, more preferably 6 to 20, and particularly preferably 6 to 12, and examples include phenyl, p-methylphenyl, and naphthyl) An amino group (preferably having 0 to 20 carbon atoms, more preferably 0 to 10, and still more preferably 0 to 6, and examples thereof include amino, methylamino, dimethylamino, diethylamino, and dibenzylamino); An alkoxy group (preferably having 1 to 20, more preferably 1 to 12, and particularly preferably 1 to 8; examples thereof include methoxy, ethoxy, and butoxy), and an aryloxy group (preferably having 6 carbon atoms). -20, more preferably 6-16, particularly preferably 6-12, for example, phenyloxy, 2-naphthyloxy and the like. An acyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as acetyl, benzoyl, formyl, pivaloyl, etc.), and alkoxycarbonyl. A group (preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 12 carbon atoms, for example, methoxycarbonyl, ethoxycarbonyl and the like), an aryloxycarbonyl group (preferably 7 carbon atoms) -20, more preferably 7-16, particularly preferably 7-10, for example, phenoxycarbonyl and the like.), Acyloxy group (preferably 1-20 carbon atoms, more preferably 2-16, particularly preferred) Is 2 to 10, and examples thereof include acetoxy and benzoyloxy. Amino group (preferably having 1 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 10 carbon atoms, for example, acetylamino, valerylamino, benzoylamino and the like), and alkoxycarbonylamino group (preferably It has 2 to 20, more preferably 2 to 16, particularly preferably 2 to 12 carbon atoms, for example, methoxycarbonylamino and the like.), Aryloxycarbonylamino group (preferably 7 to 20 carbon atoms, more preferably Is from 7 to 16, particularly preferably from 7 to 12, such as phenyloxycarbonylamino, etc.), a sulfonylamino group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 16 carbon atoms). To 12, for example, methanesulfonylamino, benzenesulfonylamino, etc. And so on. ), A sulfamoyl group (preferably having 0 to 20, more preferably 0 to 16, and particularly preferably 0 to 12 carbon atoms, for example, sulfamoyl, methylsulfamoyl, dimethylsulfamoyl, phenylsulfamoyl, etc.) ), A carbamoyl group (preferably having 0 to 20, more preferably 0 to 16, and particularly preferably 0 to 12 carbon atoms such as carbamoyl, diethylcarbamoyl, and phenylcarbamoyl), and a ureido group ( It preferably has 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, and particularly preferably 1 to 12 carbon atoms. Examples thereof include ureido, methylureide, and phenylurey), and an alkylthio group (preferably 1 to 20 carbon atoms). , More preferably 1 to 16, particularly preferably 1 to 12, for example, Luthio, ethylthio, etc.), an arylthio group (preferably having 6 to 20, more preferably 6 to 16, particularly preferably 6 to 12, and for example, phenylthio etc.), a sulfonyl group ( It preferably has 1 to 20 carbon atoms, more preferably 1 to 16, particularly preferably 1 to 12, and includes, for example, mesyl, tosyl and the like.), A sulfinyl group (preferably 1 to 20 carbon atoms, more preferably 1-16, particularly preferably 1-12, for example, methanesulfinyl, benzenesulfinyl and the like.), Phosphoric amide group (preferably 1-20 carbon atoms, more preferably 1-16, particularly preferably 1 carbon atom). To 12, for example, diethylphosphoramide, phenylphosphoramide, etc.), hydroxy group, merca Group, halogen atom (for example, fluorine atom, chlorine atom, bromine atom, iodine atom), cyano group, sulfo group, carboxy group, nitro group, hydroxam group, sulfino group, hydrazino group, sulfonylthio group, thiosulfonyl group, Examples include a heterocyclic group (for example, imidazolyl, pyridyl, furyl, piperidyl, morpholinyl, morpholino, and the like), a disulfide group, and the like.

塩 Of these groups, those capable of forming a salt may form a salt. These substituents may be further substituted. When there are two or more substituents, they may be the same or different. The substituent of the aliphatic hydrocarbon group represented by Z is preferably an aryl group, an alkoxy group, a heterocyclic group, a cyano group, an acyl group, an alkoxycarbonyl group, a sulfamoyl group, a carbamoyl group, a sulfonyl group, a nitro group, or a halogen. It is an atom, a carboxy group, or an amino group, and more preferably, an aryl group, a heterocyclic group, a cyano group, an alkoxy group, or a sulfonyl group. The aliphatic hydrocarbon group represented by Z is preferably an alkyl group, and more preferably a chain alkyl group.

The aryl group represented by Z is preferably a monocyclic or condensed aryl group having 6 to 30 carbon atoms, more preferably a monocyclic or condensed aryl group having 6 to 20 carbon atoms, for example, phenyl , Naphthyl, etc., and particularly preferably a phenyl group.

The aryl group represented by Z may have a substituent. Examples of the substituent include, in addition to the substituents listed for the aliphatic hydrocarbon group represented by Z, an alkyl group (preferably having carbon atoms). 1-20, more preferably 1-12, particularly preferably 1-8, for example, methyl, ethyl, isopropyl, n-butyl, tert-butyl, n-octyl, tert-amyl, cyclohexyl and the like. Alkenyl group (preferably having 2 to 20 carbon atoms, more preferably 2 to 12, particularly preferably 2 to 8, and examples thereof include vinyl, allyl, 2-butenyl, and 3-pentenyl.) An alkynyl group (preferably having 2 to 20 carbon atoms, more preferably 2 to 12 carbon atoms, particularly preferably 2 to 8 carbon atoms, for example, a propargyl group, a 3-pentynyl group, etc. It is below.), And the like can be applied.

As the substituent of the aryl group represented by Z, preferably an alkyl group, an aryl group, an alkoxy group, an aryloxy group, an acyl group, an alkoxycarbonyl group, an acyloxy group, an acylamino group, an alkoxycarbonylamino group, an aryloxycarbonylamino group , Sulfonylamino group, sulfamoylamino group, carbamoylamino group, ureido group, alkylthio group, arylthio group, sulfonyl group, sulfinyl group, sulfonylthio group, thiosulfonyl group, phosphoramide group, halogen atom, cyano group, carboxy group , A heterocyclic group, more preferably an alkyl group, an alkoxy group, an aryloxy group, an acyl group, an alkoxycarbonyl group, an acyloxy group, an acylamino group, an alkoxycarbonylamino group, an aryloxycarbonylamido. Group, sulfonylamino group, carbamoyl group, ureido group, alkylthio group, arylthio group, sulfonyl group, sulfinyl group, phosphoramide group, heterocyclic group, more preferably alkyl group, alkoxy group, aryloxy group, acylamino group , A sulfonylamino group, a sulfamoyl group, a carbamoyl group, a ureido group, a phosphoramide group, a carboxy group, and a heterocyclic group, and particularly preferably an alkyl group, an alkoxy group, an aryloxy group, an acylamino group, a sulfonylamino group, and a sulfamoyl group. Carbamoyl, ureido, and carboxy groups.

The heterocyclic group represented by Z is a 3- to 10-membered saturated or unsaturated heterocyclic ring containing at least one N, O or S atom, which may be a monocyclic ring, And a condensed ring may be formed. Specific examples of the heterocyclic group include, for example, thienyl, furyl, pyranyl, 2H-pyrrolyl, pyrrolyl, imidazolyl, pyrazolyl, isothiazolyl, isoxazolyl, thiazolyl, oxazolyl, 1,2,3-triazolyl, 1,2,4-triazolyl 1,3,4-oxadiazolyl, 1,3,4-thiadiazolyl, pyridyl, pyrazinyl, pyrimidinyl, pyridazinyl, indolinidyl, isoindolinidyl, 3H-indolyl, indolyl, 1H-indazolyl, purinyl, 4H-quinolizinyl, isoquinolyl, Quinolyl, phthalazinyl, naphthyridinyl, quinoxalinyl, quinazolinyl, cinnolinyl, pteridinyl, carbazolyl, β-carbonilyl, phenanthridinyl, acridinyl, perimidinyl, phenanthrolinyl, Nadinyl, fenaldazinyl, phenothiazinyl, flazanil, phenoxazinyl, isochromanyl, chromanil, pyrrolidinyl, pyrrolinyl, imidazolidinyl, imidazolinyl, pyrazolidinyl, pyrazolinyl, piperidyl, piperazinyl, indolinyl, isoindolinyl, benzonuridyl, benzoyl, benzoyl, benzoyl, benzoyl, benzoyl, benzoylamine , Benztriazolyl, triazinyl, uracil, triazopyrimidinyl and the like.

Preferably, pyrrolyl, imidazolyl, pyrazolyl, thiazolyl, oxazolyl, 1,2,3-triazolyl, 1,2,4-triazolyl, 1,3,4-oxadiazolyl, 1,3,4-thiadiazolyl, pyridyl, pyrazinyl, pyrimidinyl , Pyridazinyl, indolyl, 1H-indazolyl, purinyl, 4H-quinolizinyl, isoquinolyl, quinolyl, phthalazinyl, naphthyridinyl, quinoxalinyl, quinazolinyl, cinnolinyl, pteridinyl, tetrazolyl, benzimidazolyl, benzoxazolyl, benzotriazolyl, benztriazolyl, trizazolyl Uracil and triazopyrimidinyl.

More preferably, imidazolyl, pyrazolyl, thiazolyl, oxazolyl, 1,2,3-triazolyl, 1,2,4-triazolyl, 1,3,4-oxadiazolyl, 1,3,4-thiadiazolyl, pyridyl, pyrazinyl, pyrimidinyl, Pyridazinyl, indolyl, 1H-indazolyl, purinyl, quinolyl, phthalazinyl, naphthyridinyl, quinoxalinyl, quinazolinyl, cinnolinyl, pteridinyl, tetrazolyl, benzimidazolyl, benzoxazolyl, benzothiazolyl, benzotriazolyl, triazinyl, triazopyrimidinyl.

The heterocyclic group represented by Z may have a substituent. Examples of the substituent include, in addition to the substituents of the aliphatic hydrocarbon group represented by Z, an alkyl group ( It preferably has 1 to 20 carbon atoms, more preferably 1 to 12, particularly preferably 1 to 8, and includes, for example, methyl, ethyl, iso-propyl, tert-butyl, n-octyl, tert-amyl, cyclohexyl and the like. Alkenyl group (preferably having 2 to 20 carbon atoms, more preferably 2 to 12, particularly preferably 2 to 8, and examples thereof include vinyl, allyl, 2-butenyl, and 3-pentenyl.) An alkynyl 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 a propargyl group and a 3-pentynyl group. That.), And the like can be applied.

As the substituent of the heterocyclic group represented by Z, preferably an alkyl group, an aryl group, an alkoxy group, an aryloxy group, an acyl group, an alkoxycarbonyl group, an acyloxy group, an acylamino group, a sulfonylamino group, a sulfamoylamino group Carbamoyl group, ureido group, phosphoramide group, alkylthio group, arylthio group, sulfonyl group, sulfinyl group, sulfonylthio group, halogen atom, cyano group, nitro group, heterocyclic group, more preferably alkyl group, aryl Group, alkoxy group, acyl group, alkoxycarbonyl group, acyloxy group, acylamino group, sulfonylamino group, sulfamoyl group, sulfonylthio group, carbamoyl group, ureido group, heterocyclic group, more preferably an alkyl group, an aryl group , An alkoxy group, A sil group, an aryloxy group, an acylamino group, a sulfonylamino group, a sulfamoyl group, a carbamoyl group, a ureido group, a phosphoramide group, and a heterocyclic group, particularly preferably an alkyl group, an alkoxy group, an aryloxy group, an acylamino group, A sulfonylamino group, a sulfamoyl group, a sulfonylthio group, a carbamoyl group, a ureido group, and a heterocyclic group.

As Z, a chain alkyl group or an aryl group (for example, a phenyl group) is preferable.

M represents a cation, for example, a hydrogen ion, an alkali metal (Na, K or the like) ion, a substituted or unsubstituted ammonium ion, or the like.

Next, specific examples of the compound represented by the formula (A-3) are shown, but the invention is not limited thereto.

化合物 The compound represented by the formula (A-3) of the present invention may be a commercially available compound, or may be synthesized by a known method. For example, it can be synthesized by a reaction between a sulfonyl halide and an alkali sulfide or a reaction between a sulfinate and sulfur.

The compound of the formula (A-3) of the present invention can be prepared from water or a suitable organic solvent such as alcohols (methanol, ethanol, propanol, fluorinated alcohol), ketones (acetone, methyl ethyl ketone), dimethylformamide, dimethyl sulfoxide, methyl It can be used by dissolving it in Cellsolve or the like.

Also, by an already well-known emulsification dispersion method, it is dissolved by using an oil such as dibutyl phthalate, tricresyl phosphate, glyceryl triacetate or diethyl phthalate, and an auxiliary solvent such as ethyl acetate or cyclohexanone, and mechanically emulsified and dispersed. A product can be prepared and used. Alternatively, the powder can be dispersed and used in water by a ball mill, a colloid mill, a sand grinder mill, a Manton-Gaulin, a microfluidizer, or an ultrasonic wave by a method known as a solid dispersion method.

The compound of the formula (A-3) may be added to a layer on the side of the silver halide emulsion layer which is an image forming layer with respect to the support, that is, a silver halide emulsion layer or any other layer. It is preferably added to the silver emulsion layer or a layer adjacent thereto. The addition amount of the formula (A-3) of the present invention is in the range of 0.2 to 200 mmol, preferably 0.3 to 100 mmol, more preferably 0.5 to 30 mmol, per mol of silver. It is. These may be used alone or in combination of two or more.

Hereinafter, the compounds and constituent elements according to the present invention will be further described.

(1) Photosensitive silver halide particles The photosensitive silver halide particles (also simply referred to as silver halide particles) used in the photothermographic material of the present invention will be described.

Incidentally, the photosensitive silver halide grains in the present invention can inherently absorb light as an intrinsic property of silver halide crystals, or emit visible light or infrared light by an artificial physicochemical method. When it can be absorbed and absorbs light in any region within the light wavelength range from the ultraviolet region to the infrared region, a physicochemical change occurs in the silver halide crystal and / or on the crystal surface. Refers to silver halide crystal grains that have been processed as possible.

銀 The silver halide grains used in the present invention are themselves P.I. Glafkids: Chimie et Physique Photographique (published by Paul Montel, 1967); F. Duffin: Photographic Emulsion Chemistry (published by The Focal Press, 1966); L. It can be prepared as a silver halide grain emulsion using a method described in Zelikman et al: Making and Coating Photographic Emulsion (published by The Focal Press, 1964). That is, any of an acidic method, a neutral method, an ammonia method, and the like may be used, and a method of reacting a soluble silver salt and a soluble halide salt may be any one of a one-side mixing method, a double-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 preferable among the above methods. 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 of silver halide seed grain (nucleus) generation and grain growth, and these methods may be performed continuously at one time. Alternatively, nucleus (seed grain) formation and grain growth may be separated. It is also possible to use a method of performing this. The controlled double jet method of forming particles by controlling the particle formation conditions such as pAg and pH is preferable because the shape and size of the particles can be controlled. For example, when performing a method in which nucleation and grain growth are performed separately, first, a soluble silver salt and a soluble halogen salt are uniformly and rapidly mixed in an aqueous gelatin solution to form nuclei (seed particles) (nucleation step). Thereafter, silver halide grains are prepared by a grain growth step of growing grains while supplying a soluble silver salt and a soluble halide salt under controlled pAg, pH and the like. After grain formation, a desired silver halide emulsion can be obtained by removing unnecessary salts and the like by a desalting step by a known desalting method such as a noodle method, flocculation method, ultrafiltration method, and electrodialysis method. I can do it.

The silver halide grains preferably have a small average particle size in order to suppress white turbidity and color tone (yellow tint) after image formation and obtain good image quality, and the average particle size is less than 0.02 μm. As a value when particles are excluded from measurement, 0.035 to 0.055 μm is preferable. When the silver halide grains are cubic or octahedral so-called normal crystals, the grain size refers to the length of the edge of the silver halide grains. In the case where the silver halide grains are tabular grains, the diameter refers to a diameter when converted into a circular image having the same area as the projected area of the main surface.

銀 The silver halide grains are preferably monodispersed. The term “monodisperse” as used herein means that the coefficient of variation of the particle diameter determined by the following equation is 30% or less. It is preferably at most 20%, more preferably at most 15%.

Coefficient of variation (%) of particle size = (standard deviation of particle size / average value of particle size) × 100
Examples of the shape of the silver halide grains include cubic, octahedral, tetrahedral grains, tabular grains, spherical grains, rod-like grains, potato-like grains and the like. It is preferable to use a tabular or tabular silver particle.

場合 When tabular grains are used, the average aspect ratio is preferably 1.5 to 100, and more preferably 2 to 50. These are described in U.S. Pat. Nos. 5,264,337, 5,314,798, and 5,320,958, and can easily obtain target tabular grains. Further, grains having rounded corners of silver halide grains can also be preferably used.

There is no particular limitation on the crystal habit on the outer surface of the silver halide grains, but when a spectral sensitizing dye having crystal habit (plane) selectivity is used in the adsorption reaction of the silver sensitizing dye on the surface of the silver halide grains. It is preferable to use silver halide grains having a relatively high proportion of crystal habit adapted to the selectivity. For example, when a sensitizing dye that selectively adsorbs to a crystal plane having a Miller index of [100] is used, the ratio of the [100] plane to the outer surface of the silver halide grain is preferably high, and this ratio is preferably 50%. %, More preferably 70% or more, particularly preferably 80% or more. Incidentally, the ratio of the Miller index [100] plane is determined by the T.V. method using the adsorption dependency between the [111] plane and the [100] plane in the adsorption of the sensitizing dye. Tani: J. et al. Imaging @ Sci. , 29, 165 (1985).

The silver halide grains used in the present invention are preferably prepared by 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 at the time of forming nuclei of the silver halide grains. The low molecular weight gelatin has an average molecular weight of 50,000 or less, preferably 2000 to 40000, and more preferably 5000 to 25,000. The average molecular weight of gelatin can be measured by gel filtration chromatography. Low-molecular-weight gelatin is generally used for enzymatic degradation by adding a gelatin-degrading enzyme to an aqueous gelatin solution having an average molecular weight of about 100,000, hydrolyzing by adding an acid or alkali, and heating under atmospheric pressure or under pressure. By thermal decomposition, decomposition by irradiation with ultrasonic waves, or a combination of these methods.

濃度 The concentration of the dispersion medium (gelatin or the like) 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.

銀 As the silver halide grains, it is preferable to use a polyethylene oxide compound represented by the following general formula at the time of forming the grains.

General formula YO (CH ₂ CH ₂ O) _m [CH (CH ₃ ) CH ₂ O] _p (CH ₂ CH ₂ O) _n Y
Wherein, Y is a hydrogen atom, a -SO ₃ M, or -CO-B-COOM, M is a hydrogen atom, an alkali metal atom, ammonium group or substituted ammonium group having carbon atoms of not more than 5 alkyl group And B represents a chain or cyclic group forming an organic dibasic acid. m and n each represent 0 to 50, and p represents 1 to 100.

The above-mentioned polyethylene oxide compound is used for producing a silver halide photographic light-sensitive material, a step of producing an aqueous gelatin solution, a step of adding a water-soluble halide and a water-soluble silver salt to the gelatin solution, and coating the emulsion on a support. It has been preferably used as an antifoaming agent against remarkable foaming when the emulsion raw materials are stirred or moved, such as in the process, and the technology used as the antifoaming agent is described in, for example, JP-A-44-9497. Has been described. The polyethylene oxide compound also functions as a defoaming agent during nucleation.

ポ リ エ チ レ ン The polyethylene oxide compound represented by the above general formula is preferably used in an amount of 1% by mass or less based on silver, more preferably 0.01 to 0.1% by mass.

The above polyethylene oxide compound may be present at the time of nucleation, and is preferably added in advance to the dispersion medium before nucleation. However, it may be added during nucleation or silver used at the time of nucleation. It may be used by being added to an aqueous salt solution or an aqueous halide solution. Preferably, it is used by adding to the aqueous halide solution or both aqueous solutions at 0.01 to 2.0% by mass. Also, it is preferable that it is present for at least 50% of the time of the nucleation step, and more preferably for 70% or more. This polyethylene oxide compound may be added in the form of a powder or dissolved in a solvent such as methanol.

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

The concentrations of the silver salt aqueous solution and the halide aqueous solution used for nucleation are preferably 3.5 mol / L or less, and more preferably used in a low concentration range of 0.01 to 2.5 mol / L. The addition rate of silver ions at the time of nucleation is preferably 1.5 × 10 ^{−3 to} 3.0 × 10 ⁻¹ mol / min, more preferably 3.0 × 10 ⁻³ to 8. It is 0 × 10 ^-2 mol / min.

ＰＨ The pH at the time of nucleation can be set in the range of 1.7 to 10, but is preferably pH 2 to 6 at the alkaline pH in order to broaden the particle size distribution of nuclei to be formed. Further, 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 may be added to the light-sensitive layer by any method. At this time, the silver halide grains are preferably arranged so as to be close to a reducible silver source (silver aliphatic carboxylate).

The silver halide of the present invention is prepared in advance, and then added to a solution for preparing silver aliphatic carboxylate particles, a silver halide preparing step and an aliphatic silver carboxylate particle preparing step. Is preferred from the viewpoint of production control because it can be handled separately. However, as described in British Patent No. 1,447,454, when preparing aliphatic carboxylic acid silver salt particles, a halogen component such as a halide ion is replaced with an aliphatic carboxylic acid. By coexisting with a silver salt-forming component and injecting silver ions into the silver salt, silver aliphatic carboxylate particles can be produced almost simultaneously with the production. It is also possible to prepare a silver halide grain by converting a silver salt of an aliphatic carboxylic acid with a halogen-containing compound by reacting the compound with a halogen. That is, a silver halide-forming component is allowed to act on a previously prepared solution or dispersion of a silver salt of an aliphatic carboxylic acid, or a sheet material containing the silver salt of an aliphatic carboxylic acid, to thereby form a part of the silver salt of an aliphatic carboxylic acid. 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, and 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, metal halides, ammonium halides and the like. Onium halides such as trimethylphenylammonium bromide, cetylethyldimethylammonium bromide and trimethylbenzylammonium bromide, for example, halogens such as iodoform, bromoform, carbon tetrachloride and 2-bromo-2-methylpropane Hydrocarbons, N N-halogen compounds such as bromosuccinimide, N-bromophthalimide, N-bromoacetamide, and others such as triphenylmethyl chloride, triphenylmethyl bromide, 2-bromoacetic acid, 2-bromoethanol, dichlorobenzophenone, and the like. . In this manner, the silver halide can also be prepared by converting a part or all of the silver in the organic acid silver salt to silver halide by reacting the organic acid silver with the halide ion. Further, silver halide grains produced by converting a part of the aliphatic carboxylic acid silver salt to separately prepared silver halide may be used in combination.

These silver halide grains, separately prepared silver halide grains, silver halide grains obtained by conversion of aliphatic carboxylic acid silver salt, 0.001 to 0.7 mole per mole of aliphatic carboxylic acid silver salt, Preferably, 0.03 to 0.5 mol is used.

The silver halide grains preferably contain transition metal ions 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. These metal ions may be directly introduced into silver halide as a metal salt, 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 to 1 × 10 ⁻² mol, preferably 1 × 10 ⁻⁸ to 1 × 10 ⁻⁴ mol, per 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 elements of Groups 6 to 11 of the periodic table, L represents a ligand, and m represents 0,-, 2-, 3- or 4-. Specific examples of the ligand represented by L include halogen ions (fluorine, chlorine, bromine, and iodine ions), cyanide, cyanate, thiocyanate, selenocyanate, tellurocyanate, azide, and aquo. And nitrosyl, thionitrosyl and the like, preferably aquo, nitrosyl and thionitrosyl. If an aquo ligand is present, it preferably occupies one or two of the ligands. L may be the same or different.

The compound which provides the ion or complex ion of these metals is preferably added during silver halide grain formation and incorporated into silver halide grains. Preparation of silver halide grains, that is, nucleation, growth, and physical ripening It may be added at any stage before and after chemical sensitization, but is particularly preferably added at the stage of nucleation, growth, and physical ripening, more preferably at the stage of nucleation and growth. Preferably, it is added at the stage of nucleation. In the addition, it may be added in several divided portions, may be added uniformly in the silver halide grains, or may be added uniformly to the silver halide grains, as disclosed in JP-A-63-29603, JP-A-2-306236 and JP-A-2-306236. As described in JP-A-167545, JP-A-4-76534, JP-A-6-110146, JP-A-5-273683 and the like, the particles can be contained in the particles with a distribution.

These metal compounds can be added by dissolving in water or a suitable organic solvent (alcohols, ethers, glycols, ketones, esters, amides, etc.). Alternatively, an aqueous solution in which a metal compound and sodium chloride and potassium chloride are dissolved together is added to a water-soluble silver salt solution or a water-soluble halide solution during grain formation, or a silver salt solution and a halide solution are simultaneously mixed. In this case, a method of preparing silver halide grains by a method of simultaneous mixing of three liquids, adding a required amount of an aqueous solution of a metal compound into a reaction vessel during grain formation, There is a method in which another silver halide grain doped with a metal ion or complex ion in advance during silver preparation is added and dissolved. In particular, a method of adding an aqueous solution of a powder of a metal compound or an aqueous solution in which a metal compound is dissolved together with sodium chloride and potassium chloride to a water-soluble halide solution is preferable. When adding to the surface of the particles, a required amount of an aqueous solution of a metal compound can be charged into the reaction vessel immediately after the formation of the particles, during or at the end of physical ripening, or at the time of chemical ripening.

The separately prepared photosensitive silver halide grains can be desalted by a known desalting method such as a noodle method, flocculation method, ultrafiltration method, or electrodialysis method, but can also be used without desalting. .

The aliphatic carboxylic acid silver salt of the present invention is a reducible silver source, and is preferably a silver salt of an aliphatic carboxylic acid having 10 to 30 carbon atoms, preferably 15 to 25 carbon atoms. Examples of suitable silver salts include the following.

(2) Non-photosensitive organic silver salt particles The organic silver salt that can be used in the present invention is relatively stable to light, but is exposed to a photocatalyst (such as a latent image of a photosensitive silver halide) and a reducing agent. It is a silver source that can release silver ions when heated to 80C to 250C in the presence. Examples of the organic silver salt include a silver salt of a long-chain aliphatic carboxylic acid, a silver salt of a compound containing a mercapto group or a thione group and a derivative thereof, a silver salt of a nitrogen-containing heterocyclic compound, or a ligand whose total ligand is relative to silver ion. Organic or inorganic complexes described in Research Disclosure (hereinafter abbreviated as RD) 17029 and 29963 having a stability constant of 4.0 to 10.0 can be given.

に お い て In the present invention, a long-chain aliphatic carboxylic acid is preferable as the organic acid of the organic silver salt. Examples of the long-chain aliphatic carboxylic acid useful in the present invention have 10 to 30 carbon atoms, for example, cellotic acid (25 carbon atoms), behenic acid (22), arachidic acid (20), stearic acid ( 18), palmitic acid (16), myristic acid (14), lauric acid (12) and the like, and aliphatic carboxylic acids having 12 to 25 carbon atoms are preferable. Of these, those particularly useful in the present invention are behenic acid, arachidic acid, stearic acid and palmitic acid.

In the present invention, examples of the organic silver other than the long-chain aliphatic carboxylic acid include carboxyalkylthioureas such as 1- (3-carboxypropyl) thiourea and 1- (3-carboxypropyl) -3,3-dimethylthiourea. A polymer of an aldehyde and a hydroxy-substituted aromatic carboxylic acid, such as a reaction product of an aldehyde (formaldehyde, acetaldehyde, butyraldehyde, etc.) and a hydroxy-substituted acid (eg, salicylic acid, benzoic acid, 3,5-dihydroxybenzoic acid); Reaction products; thiones such as 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, - amino-5-benzylthio-1,2,4-triazole, and nitrogen-containing heterocyclic compounds such as benzotriazole; saccharin, 5-chloro salicylaldoxime like, and mercaptides the like. The silver compounds of these organic acids are in the form of silver salts or complexes.

好 ま し い In the present invention, a preferable organic silver salt is a long-chain aliphatic carboxylic acid silver salt, which easily releases silver during thermal development and is easy to use. Among them, silver behenate is the most easily used aliphatic carboxylic acid.

In the silver salt photothermographic dry imaging material of the present invention, the exact content of silver behenate is preferably from 70 to 99% by mass, particularly preferably from 78.0 to 99% by mass, based on the organic silver salt used. %. The organic acid of the organic silver salt used may be a long-chain carboxylic acid alone, or may be mixed with an organic acid such as the nitrogen-containing heterocyclic compound or thio compound. It is at most 5% by mass, preferably at most 1% by mass, more preferably at most 0.1% by mass.

The organic silver salt can be obtained by mixing a water-soluble silver compound and an organic acid metal salt compound which forms a complex with silver, and is described in Japanese Patent Application Laid-Open No. 9-127463, which describes a forward mixing method, a reverse mixing method, a simultaneous mixing method, and the like. A controlled double jet method or the like as described can be preferably used. For example, an alkali metal salt (eg, sodium hydroxide, potassium hydroxide, etc.) is added to an organic acid and neutralized with nitric acid to prepare an organic acid alkali metal salt soap (eg, sodium behenate, sodium arachidate, etc.). Thereafter, the metal salt soap and the aqueous silver nitrate solution are mixed by a controlled double jet method to produce crystal grains of an organic silver salt. At that time, silver halide grains may be mixed.

The organic silver salt particles according to the present invention preferably have an average thickness of 0.005 to 0.05 μm and an average particle size of 0.05 to 0.5 μm, and particularly preferably have an average thickness of 0.005 to 0 μm. 0.03 μm. Regarding the average particle diameter, the organic silver salt after dispersion is diluted and dispersed on a grid with a carbon support film, photographed directly with a transmission electron microscope (2000FX, manufactured by JEOL Ltd.) at 5,000 times magnification, and then scanned with a scanner. The negative is captured as a digital image, and the particle diameter (equivalent circle diameter) of at least 300 particles on the screen is measured using image processing software to calculate the average particle diameter.

The above average thickness is calculated by a method using a TEM (transmission electron microscope) as shown below. First, the photosensitive layer applied on the support is attached to an appropriate holder with an adhesive, and an ultra-thin section having a thickness of 0.1 to 0.2 μm is prepared using a diamond knife in a direction perpendicular to the surface of the support. I do. The prepared ultrathin section 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 a TEM). A 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, as the visual field to be observed, it is preferable to appropriately select a portion where there is no break or looseness in the section. It is preferable to use a carbon film supported by an organic film such as ultra-thin collodion or formvar, and more preferably, the carbon film is formed on a rock salt substrate and obtained by dissolving and removing the substrate. This is a film of carbon alone obtained by removing the solvent and ion etching. The acceleration voltage of the TEM is preferably from 80 to 400 kV, particularly preferably from 80 to 200 kV.

For more information on electron microscopy techniques and sample preparation techniques, see "The Japanese Society of Electron Microscopy, Kanto Chapter / Medical and Biological Electron Microscopy" (Maruzen), "Japan Electron Microscopy Society, Kanto Section", Electron Microscopy Biological Specimens Production method ”(Maruzen) can be referred to.

は As for the TEM image recorded on an appropriate medium, it is preferable that one image is decomposed into at least 1024 pixels × 1024 pixels, preferably 2048 pixels × 2048 pixels or more and subjected to image processing by a computer. 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 created, and a portion corresponding to organic silver is extracted by a binarization process.

３００ The thickness of the extracted organic silver salt particles is measured using 300 or more image processing software, and the average value is determined.

The method for obtaining organic silver salt particles having a shape having an average thickness of 0.005 to 0.05 μm and an average particle size of 0.05 to 0.5 μm is not particularly limited. It is effective to keep good the state and / or the mixed state when adding silver nitrate to the organic acid alkali metal salt soap, and to optimize the ratio of silver nitrate that reacts with the organic acid alkali metal salt soap. is there.

The shape of the organic silver salt particles according to the present invention is various, such as tabular, rod-like, needle-like, and spherical, and is not particularly limited. Is large and the silver supply amount is large.

に お い て In the present invention, it is not preferable to mechanically disperse and pulverize the organic silver salt particles after the formation, and it is not particularly preferable in the method of forming the silver halide particles during the production of the organic silver salt. However, when re-dispersing a dry cake having organic silver salt particles and silver halide particles, a disperser suitable for the re-dispersion may be used. In the case of a short time, a strong one such as a high-pressure homogenizer may be used.

Examples of a disperser that can be used for pre-dispersing the cake include a media disperser, a high-pressure homogenizer, a general stirrer such as an anchor type and a propeller type, a high-speed rotary centrifugal radiation type agitator (dissolver), and a high-speed rotary shear type agitator (homomixer). ) Can be used. Further, as the media disperser, a ball mill, a planetary ball mill, a rolling mill such as a vibrating ball mill, a bead mill as a medium stirring mill, an attritor, and other basket mills can be used. Various types can be used, such as a type that collides with a plug or the like, a type that divides a liquid into a plurality of liquids and then collides the liquids at a high speed, and a type that passes a thin orifice.

Examples of ceramics used for ceramic beads used at the time of media dispersion 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), SiO ₂ -nH ₂ O, silicon nitride, yttrium-stabilized zirconia, zirconia toughened alumina, and the like are preferable. Yttrium-stabilized zirconia and zirconia reinforced alumina (these ceramics containing zirconia are hereinafter abbreviated as zirconia) are particularly preferably used because, for example, the generation of impurities due to friction between the beads and the disperser during dispersion is small.

In devices used for dispersing the aliphatic carboxylic acid silver salt particles, ceramics such as zirconia, alumina, silicon nitride, and boron nitride or diamond are used as a material of a member with which the aliphatic carboxylic acid silver salt particles are in contact. It is preferable to use zirconia. When performing the above dispersion, the binder concentration is preferably 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. Preferred operating conditions for the main dispersion include, for example, when a high-pressure homogenizer is used as the dispersing means, 29.42 to 98.06 MPa, and the number of operations is preferably two or more. When a media dispersing machine is used as the dispersing means, a preferable condition is a peripheral speed of 6 to 13 m / sec.

In the present invention, the compound functioning as a crystal growth inhibitor or dispersant for the aliphatic silver carboxylate particles refers to a silver aliphatic carboxylate under the condition in which the compound is present in the step of producing the silver aliphatic carboxylate particles. Refers to a compound having a function and an effect of reducing the particle size and monodispersing when produced under the condition where coexistence is not caused. 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. The preferable addition amount is 10 to 200% by mass based on the aliphatic silver carboxylate.

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 isohexanoic acid are also preferable. In this case, a preferable side chain is an alkyl group or alkenyl group having 4 or less carbon atoms. Also, 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 seracolenic acid. Can be The preferred addition amount is 0.5 to 10 mol% of the silver aliphatic carboxylate.

Glycosides such as glucoside, galactoside, and 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; 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. The preferable addition amount is 0.1 to 20% by mass based on the aliphatic silver carboxylate.

Alcohols having 10 or less carbon atoms, preferably secondary alcohols and tertiary alcohols, are reduced in viscosity by increasing the solubility of sodium aliphatic carboxylate in the charging step, and are monodispersed and reduced by increasing the stirring efficiency. Particle size. Branched aliphatic carboxylic acids and aliphatic unsaturated carboxylic acids have higher steric hindrance than silver aliphatic carboxylate, which is the main component when silver aliphatic carboxylate is crystallized, and 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, the biggest difference in the composition of the photothermographic material compared to the conventional silver halide photographic material is that the latter material has fog and printout silver before and after development processing. That is, a large amount of photosensitive silver halide, an organic silver salt and a reducing agent which may cause generation of (printed silver). For this reason, a high degree of fogging prevention and image stabilization technology is essential for photothermographic materials in order to maintain storage stability not only before development but also after development. Conventionally, in addition to the aromatic heterocyclic compound which suppresses the growth and development of the fog nucleus, a mercury compound such as mercury acetate having a function of oxidizing and eliminating the fog nucleus has been used as a very effective storage stabilizer. However, the use of this mercury compound was problematic in terms of safety and environmental conservation.

(3) Antifoggant and image stabilizer The antifoggant and image stabilizer used in the photothermographic material of the present invention are described below.

In the photothermographic material of the present invention, since a reducing agent such as a bisphenol is mainly used as a reducing agent, a compound capable of inactivating the reducing agent by generating active species capable of extracting hydrogen is contained. Is preferred. It is preferably a compound capable of generating free radicals as a reactive species at the time of exposure as a colorless photo-oxidizable substance.

Accordingly, any compound having these functions may be used, but an organic free radical comprising a plurality of atoms is preferable. A compound having any structure may be used as long as it has such a function and does not cause any particular adverse effect on the photothermographic material.

Compounds that generate these free radicals may be carbocyclic or heterocyclic in order to have stability such that the generated free radicals can be contacted for a sufficient time to react with and inactivate the reducing agent. Those having an aromatic group of the formula are preferred.

ビ Representative examples of these compounds include the following biimidazolyl compounds and iodonium compounds.

@Bimidazolyl compounds include those represented by the following general formula [1].

In the formula, R ¹ , R ² and R ³ (which may be the same or different) each represent an alkyl group, an alkenyl group, an alkoxy group, an aryl group, a hydroxyl group, a halogen atom, an aryloxy group, an alkylthio group, an arylthio group, It represents an acyl group, a sulfonyl group, an acylamino group, a sulfonylamino group, an acyloxy group, 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 and a cyano group.

ビ The above biimidazolyl compound can be produced by the production method described in US Pat. No. 3,734,733 and British Patent 1,271,177 and a method analogous thereto. Details and preferred specific examples of the substituent are described in, for example, JP-A-2000-321711.

ヨ ー Also, similarly suitable compounds include iodonium compounds represented by the following general formula [2].

Wherein Q ₁ includes the atoms necessary to complete a 5- to 7-membered ring, and the necessary atoms are selected from carbon, nitrogen, oxygen and sulfur. R ¹¹ , R ¹² and R ¹³ (which may be the same or different) each represent a hydrogen atom, an alkyl group, an alkenyl group, an alkoxy group, an aryl group, a hydroxyl group, a halogen atom, an aryloxy group, an alkylthio group, an arylthio group, It represents an acyl group, a sulfonyl group, an acylamino group, a sulfonylamino group, an acyloxy group, 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 and a cyano group. Any two of R ¹¹ , R ¹² and R ¹³ may be bonded to each other to form a ring.

R ¹⁴ represents a carboxylate group or O ⁻ . m represents 0 or 1.

When R ¹³ is a sulfo group or a carboxyl group, m is 0, and R ¹⁴ is O ^-.

X ^- is an anionic counterion, as suitable examples _{^{CH 3 COO -, CH 3 SO}} 3 - and PF ₆ ^- is.

特 に Of these, particularly preferred compounds are represented by the following general formula [3].

Here, R ¹¹ , R ¹² , R ¹³ , R ¹⁴ , X ⁻ and m have the same meanings as in the general formula [2], and Y represents a carbon atom (—CH ＝; benzene ring) or a nitrogen atom (—N =; Pyridine ring).

{The above iodonium compounds are available from Org. Syn. , 1961 and by Fieser: Advanced @ Organic @ Chemistry (Reinhold, NY, 1961) and a method analogous thereto. Details and preferred specific examples of the substituent are described in, for example, JP-A-2000-321711 (supra).

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 of the constituent layers of the light-sensitive material of the present invention, but is preferably contained near the reducing agent.

As the compound that inactivates the reducing agent and prevents the reducing agent from reducing the silver salt of the aliphatic carboxylic acid to silver, it is preferable that the reactive species is not a halogen atom, but the halogen atom is released as an active species. Compounds can also be used in combination with compounds that release active species that are not halogen atoms. Many compounds that can release a halogen atom as an active species are known, and a good effect can be obtained by using them in combination.

具体 Specific examples of the compounds that generate 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 is -C (= O) -, - SO- or -SO ₂ - represents a.

The aryl group represented by Q ₂ may be monocyclic or condensed, preferably a monocyclic or bicyclic aryl group having 6 to 30 carbon atoms, more preferably a phenyl group or a naphthyl group, More preferably, it 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 a single ring, Further, a condensed ring may be formed with another ring.

詳細 The details of the substituent are described in paragraphs “0100” to “0103” of JP-A-2001-263350.

The addition amount of these compounds is preferably within a range in which the increase in printout silver due to the formation of silver halide does not cause a problem, and is preferably at most 150% or less, more preferably 100% or less, based on the compound that does not generate active halogen radicals. % Is preferable.

The photothermographic material may contain, in addition to the above compounds, compounds conventionally known as antifoggants, but compounds capable of generating the same reactive species as the above compounds. Or a compound having a different antifogging mechanism. For example, U.S. Pat. Nos. 3,589,903, 3,874,946, 4,546,075, 4,452,885, 4,756,999, JP-A-59-57234, Compounds described in JP-A-9-288328 and JP-A-9-90550 are exemplified. Further, other antifoggants include the compounds disclosed in U.S. Pat. No. 5,028,523 and European Patents 600,587, 605,981 and 631,176.

(4) Silver ion reducing agent In the present invention, as a silver ion reducing agent (sometimes simply referred to as a reducing agent), US Pat. Nos. 3,589,903 and 4,021,249 or British Patent 1, 486,148 and JP-A-51-51933, 50-36110, 50-16023, 52-84727 or JP-B-51-35727, for example, U.S. Pat. Nos. 3,672,904, such as 2,2'-dihydroxy-1,1'-binaphthyl and 6,6'-dibromo-2,2'-dihydroxy-1,1'-binaphthyl. Bisnaphthols, for example, 4-benzenesulfonamidophenol, 2-benzenesulfonamidophenol, 2,6-dichloro-4-benzenes Sulfonamidophenol or sulfonamidonaphthols as described in U.S. Pat. No. 3,801,321 such as rufonamide phenol and 4-benzenesulfonaminaphthol can be used.

However, in the present invention, as the silver ion reducing agent, a compound represented by formula (A-4) is preferable. The general formula (A-4) will be described in detail below.

In Formula (A-4), R ₁₁ and R ₁₂ each independently represent a hydrogen atom, a 3 to 10-membered non-aromatic cyclic group, or a 5 to 6 aromatic cyclic group. However, R ₁₁ and R ₁₂ are not simultaneously hydrogen atoms. R ₁₃ and R ₁₄ each independently represent a hydrogen atom, an alkyl group, a cycloalkyl group, an alkenyl group, a cycloalkenyl group, an aryl group or a heterocyclic group; Q represents a group that can be substituted on a benzene ring; Represents an integer of 0 to 2. When there are a plurality of Qs, each Q may be the same or different.

In the general formula (A-4), R ₁₁ and R ₁₂ each independently represent a hydrogen atom, a 3- to 10-membered non-aromatic cyclic group or a 5- to 6-membered aromatic cyclic group, Specific examples of the non-aromatic cyclic group include cyclopropyl, aziridyl, oxiranyl as the 3-membered ring, cyclobutyl, cyclobutenyl, oxetanyl, azetidinyl as the 4-membered ring, and cyclopentyl, cyclopentenyl, cyclopentadienyl, and tetrahydrofuran as the 5-membered ring. Nil, pyrrolidinyl, tetrahydrothienyl, 6-membered ring is cyclohexyl, cyclohexenyl, cyclohexadienyl, tetrahydropyranyl, pyranyl, piperidinyl, dioxanyl, tetrahydrothiopyranyl, norcalanyl, norpinanyl, norbornyl, 7-membered ring is cycloheptyl, Cycloheptynyl, shik Heptadienyl, 8-membered ring is cyclooctanyl, cyclooctenyl, cyclooctadienyl, cyclooctatrienyl, 9-membered ring is cyclononanyl, cyclononenyl, cyclononadienyl, cyclononatrienyl, 10-membered ring is cyclodecanyl, cyclodecenyl , Cyclodecadienyl, cyclodecatrienyl and the like.

Preferably it is a 3- to 6-membered ring, more preferably a 5- to 6-membered ring, most preferably a 6-membered ring, and among them, a hydrocarbon ring containing no hetero atom is preferable. The ring may form a spiro bond with another ring through a spiro atom, or may be condensed in any way with another ring including an aromatic ring. The ring may have any substituent. Specific examples of the substituent include a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom, etc.), an alkyl group (e.g., a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, an iso-pentyl group, 2-ethyl-hexyl group, octyl group, decyl group, etc., cycloalkyl group (eg, cyclohexyl group, cycloheptyl group, etc.), alkenyl group (eg, ethenyl-2-propenyl group, 3-butenyl group, 1-methyl) -3-propenyl group, 3-pentenyl group, 1-methyl-3-butenyl group, etc.), cycloalkenyl group (eg, 1-cycloalkenyl group, 2-cycloalkenyl group, etc.), alkynyl group (eg, ethynyl group, 1-propynyl group, etc.), alkoxy group (for example, methoxy group, ethoxy group, propoxy group, etc.), alkylcarbonyloxy group For example, acetyloxy group and the like, alkylthio group (for example, methylthio group, trifluoromethylthio group and the like), carboxyl group, alkylcarbonylamino group (for example, acetylamino group and the like), ureido group (for example, methylaminocarbonylamino group and the like) ), An alkylsulfonylamino group (eg, methanesulfonylamino group), an alkylsulfonyl group (eg, methanesulfonyl group, trifluoromethanesulfonyl group, etc.), a carbamoyl group (eg, carbamoyl group, N, N-dimethylcarbamoyl group, N -Morpholinocarbonyl group, etc.), sulfamoyl group (sulfamoyl group, N, N-dimethylsulfamoyl group, morpholinosulfamoyl group, etc.), trifluoromethyl group, hydroxyl group, nitro group, cyano group, alkyl sulfone (E.g., methanesulfonamide group, butanesulfonamide group, etc.), alkylamino group (e.g., amino group, N, N-dimethylamino group, N, N-diethylamino group, etc.), sulfo group, phosphono group, sulfite Group, sulfino group, alkylsulfonylaminocarbonyl group (eg, methanesulfonylaminocarbonyl group, ethanesulfonylaminocarbonyl group, etc.), alkylcarbonylaminosulfonyl group (eg, acetamidosulfonyl group, methoxyacetamidosulfonyl group, etc.), alkynylaminocarbonyl group (Eg, acetamidocarbonyl group, methoxyacetamidocarbonyl group, etc.), alkylsulfinylaminocarbonyl group (eg, methanesulfinylaminocarbonyl group, ethanesulfinylaminocarbonyl group) Etc.). When there are two or more substituents, they may be the same or different. Particularly preferred substituents are alkyl groups.

Next, with respect to the 5- to 6-membered aromatic cyclic group represented by R ₁₁ and R ₁₂ , the aromatic carbocycle may be a single ring or a condensed ring, preferably a monocyclic group having 6 to 30 carbon atoms. A ring or bicyclic aromatic carbocycle (for example, a benzene ring, a naphthalene ring, etc.) may be mentioned, but a benzene ring is preferably used. The aromatic hetero ring is preferably a 5- to 6-membered aromatic hetero ring optionally having a condensed ring. More preferably, it is a 5-membered aromatic hetero ring optionally having a condensed ring. As such a hetero ring, preferably imidazole, pyrazole, thiophene, furan, pyrrole, 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, pyrazole, thiophene, furan, pyrrole, Triazole, thiadiazole, tetrazole, thiazole, benzimidazole, benzothiazole, In is preferably a thiophene, furan, thiazole. The ring may be condensed in any manner with other rings, including aromatic rings. Further, the ring may have any substituent. Examples of the substituent include the same substituents as described above on the 3- to 10-membered non-aromatic cyclic group.

The most preferred combination of R ₁₁ and R ₁₂ is that R ₁₁ is a 5-membered aromatic heterocyclic group and R ₁₂ is a hydrogen atom.

R ₁₃ and R _{14 each} represent a hydrogen atom, an alkyl group, a cycloalkyl group, an alkenyl group, a cycloalkenyl group, an aryl group, or a heterocyclic group. Specifically, the alkyl group is an alkyl group having 1 to 10 carbon atoms. Preferably, there is. Specific examples of the alkyl group, cycloalkyl group, alkenyl group, and cycloalkenyl group represented by R ₁₃ and R ₁₄ include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a t-butyl group, a pentyl group, iso-pentyl group, 2-ethyl-hexyl group, octyl group, decyl group, cyclohexyl group, cycloheptyl group, 1-methylcyclohexyl group, ethenyl-2-propenyl group, 3-butenyl group, 1-methyl-3-propenyl Group, 3-pentenyl group, 1-methyl-3-butenyl group, 1-cycloalkenyl group, 2-cycloalkenyl group, ethynyl group, 1-propynyl group and the like. R ₁₃ is preferably a methyl group, an ethyl group, an isopropyl group, a t-butyl group, a cyclohexyl group, a 1-methylcyclohexyl group, or the like. More preferred are a methyl group, a t-butyl group and a 1-methylcyclohexyl group, and most preferred are a t-butyl group and a 1-methylcyclohexyl group. R ₁₄ is preferably a methyl group, an ethyl group, an isopropyl group, a t-butyl group, a cyclohexyl group, a 1-methylcyclohexyl group, a 2-hydroxyethyl group, or the like. More preferably, they are a methyl group and a 2-hydroxyethyl group. Specific examples of the aryl group represented by R ₁₃ and R ₁₄ include a phenyl group, a naphthyl group, and an anthranyl group. Specific examples of the heterocyclic groups represented by R ₁₃ and R ₁₄ include pyridine, quinoline, isoquinoline, imidazole, pyrazole, triazole, oxazole, thiazole, oxadiazole, thiadiazole, and tetrazole. And a non-aromatic heterocyclic group such as a piperidino group, a morpholino group, a tetrahydrofuryl group, a tetrahydrothienyl group, and a tetrahydropyranyl group. These groups may further have a substituent, and examples of the substituent include the aforementioned substituents on the ring.

The most preferred combination of R ₁₃ and R ₁₄ is that R ₁₃ is a tertiary alkyl group (eg, t-butyl group, 1-methylcyclohexyl group, etc.) and R ₁₄ is a primary alkyl group (eg, methyl group, 2- Hydroxyethyl group).

Q represents a group that can be substituted on the benzene ring, and specifically, an alkyl group having 1 to 25 carbon atoms (a methyl group, an ethyl group, a propyl group, an isopropyl group, a t-butyl group, a pentyl group, a hexyl group, Cyclohexyl group), 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 , An aryl group (such as a phenyl group), a heterocyclic group (a pyridyl group, a thiazolyl group, an oxazolyl group, an imidazolyl group, a furyl group, a pyrrolyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a selenazolyl group, a slipholanyl group, a piperidinyl group, a pyrazolyl group) Group, tetrazolyl group, etc.), halogen atom (chlorine 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, butane Sulfonamide group, hexanesulfonamide group, cyclohexanesulfonamide group, benzenesulfonamide group, etc., sulfamoyl group (aminosulfonyl group, methylaminosulfonyl group, dimethylaminosulfonyl group, butylamine A nosulfonyl group, a hexylaminosulfonyl group, a cyclohexylaminosulfonyl group, a phenylaminosulfonyl group, a 2-pyridylaminosulfonyl group, etc., a urethane group (methylureido group, ethylureido group, pentylureido group, cyclohexylureide group, phenylureide 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 (acetone) Toamide 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. These groups may be further substituted with these groups. n represents an integer of 0 to 2, and most preferably, n is 0. When there are a plurality of Qs, each Q may be the same or different.

{Examples of the compound represented by formula (A-4) are shown below.

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 the organic silver salt, the reducing agent, and other additives. The suitable amount is from 05 mol to 10 mol, preferably from 0.1 mol to 3 mol. Further, within this range, two or more of the silver ion reducing agents of the present invention may be used in combination. Further, it can be used in combination with the above-mentioned reducing agents having different chemical structures. In the present invention, it is preferable that the reducing agent be added to and mixed with a photosensitive emulsion solution composed of photosensitive silver halide and organic silver salt particles and a solvent immediately before coating, and the photographic performance fluctuation due to the stagnation time is small, which is preferable. is there.

(5) Chemical sensitization and spectral sensitization of photosensitive silver halide The photosensitive silver halide can be subjected to chemical sensitization. For example, according to the methods described in Japanese Patent Application Nos. 2000-57004 and 2000-61942, the use of a compound that releases a chalcogen such as sulfur, selenium, or tellurium, or a noble metal compound that releases a noble metal ion such as a gold ion allows chemical reaction. A sensitizing center (chemical sensitizing nucleus) can be formed and provided. In particular, it is preferable to chemically sensitize with an organic sensitizer containing a chalcogen atom. The organic sensitizer containing a chalcogen atom is preferably a compound having a group capable of being adsorbed to silver halide and a site of an unstable chalcogen atom.

As these organic sensitizers, organic sensitizers having various structures disclosed in JP-A-60-150046, JP-A-4-109240, and JP-A-11-218874 can be used. It is preferable that at least one of these compounds has a structure in which a chalcogen atom is connected to a carbon atom or a phosphorus atom by a double bond.

The amount of the chalcogen compound used as the organic sensitizer varies depending on the chalcogen compound to be used, silver halide grains, the reaction environment when performing chemical sensitization, and the like, but is 10 ^-8 to 10 ^-2 per mol of silver halide. Mole is preferable, and more preferably 10 ^-7 to 10 ^-3 mole is used. The chemical sensitization environment is not particularly limited, but in the presence of a compound capable of eliminating or reducing the size of chalcogenide or silver nuclei on the photosensitive silver halide grains, and particularly, in the presence of silver nuclei. In the presence of an oxidizable oxidizing agent, chalcogen sensitization is preferably performed using an organic sensitizer containing a chalcogen atom. As the sensitizing condition, the pAg is preferably 6 to 11, more preferably 7 to 11. -10, and the pH is preferably 4-10, more preferably 5-8, and the sensitization is preferably performed at a temperature of 30 ° C. or less.

Therefore, in the photothermographic material of the present invention, the photosensitive silver halide is treated with an organic sensitizer containing a chalcogen atom at a temperature of 30 ° C in the presence of an oxidizing agent capable of oxidizing silver nuclei on the grains. It is preferable to use a photosensitive emulsion which has been subjected to chemical sensitization at a temperature of not more than ℃, mixed with a silver salt of an aliphatic carboxylic acid, dispersed, dehydrated and dried.

The chemical sensitization using these organic sensitizers is preferably performed in the presence of a spectral sensitizing dye or a heteroatom-containing compound having adsorptivity to silver halide grains. By performing chemical sensitization in the presence of a compound having an adsorptive property to silver halide, dispersion of the central core of the chemical sensitization can be prevented, and high sensitivity and low fog can be achieved. Although the spectral sensitizing dye will be described later, the heteroatom-containing compound having adsorptivity to silver halide is preferably a nitrogen-containing heterocyclic compound described in JP-A-3-24537. In the nitrogen-containing heterocyclic compound, the heterocycle may be pyrazole, pyrimidine, 1,2,4-triazole, 1,2,3-triazole, 1,3,4-thiadiazole, 1,2,3-thiadiazole, 1,2 , 4-thiadiazole, 1,2,5-thiadiazole, 1,2,3,4-tetrazole, pyridazine, 1,2,3-triazine, etc., and a ring in which two or three of these rings are bonded, for example, Each ring such as triazolotriazole, diazaindene, triazaindene, and pentaazaindene can be exemplified. A heterocyclic ring in which a monocyclic heterocycle and an aromatic ring are condensed, for example, phthalazine, benzozomidazole, indazole, benzothiazole and the like can also be applied.

Of these, azaindene rings are preferred, and azaindene compounds having a hydroxyl group as a substituent, such as hydroxytriazaindene, tetrahydroxyazaindene, and hydroxypentaazaindene derivatives, are more preferred.

The heterocyclic ring may have a substituent other than a 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. Can be

The addition amount of these heterocyclic compounds varies over a wide range depending on the size, composition, and other conditions of the silver halide grains, but the approximate amount is from 10 ^-6 mol to 1 mol per mol of silver halide. And preferably in the range of 10 ^-4 mol to 10 ^-1 mol.

Noble metal sensitization can be applied to the photosensitive silver halide using a compound that releases a noble metal ion such as a gold ion. For example, chloroaurate or an organic gold compound can be used as a gold sensitizer.

In addition to the above-described sensitization methods, reduction sensitization methods and the like can also be used. Examples of shell-like compounds for reduction sensitization include ascorbic acid, thiourea dioxide, stannous chloride, hydrazine derivatives, and borane. Compounds, silane compounds, polyamine compounds and the like can be used. Reduction sensitization can be achieved by ripening the emulsion while maintaining the pH of the emulsion at 7 or more or the pAg at 8.3 or less.

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

It is preferable that the photosensitive silver halide is subjected to spectral sensitization by adsorbing a spectral sensitizing dye. As the spectral sensitizing dye, a cyanine dye, a merocyanine dye, a complex cyanine dye, a complex merocyanine dye, a holopolar cyanine dye, a styryl dye, a hemicyanine dye, an oxonol dye, a hemioxonol dye, and the like can be used. For example, JP-A-63-159814, JP-A-60-140335, JP-A-63-231437, JP-A-63-259651, JP-A-63-304242, JP-A-63-15245, U.S. Pat. , 740,455, 4,741,966, 4,751,175, and 4,835,096.

Useful sensitizing dyes are described, for example, in the documents described or cited in RD17643, page 23, section IV-A (December 1978) and 184311, 437, section X (August 1978). In particular, it is preferable to use a sensitizing dye having a spectral sensitivity suitable for the spectral characteristics of the light source of various laser imagers and scanners. For example, compounds described in JP-A-9-34078, JP-A-9-54409 and JP-A-9-80679 are preferably used.

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

に お い て In the present invention, a sensitizing dye having a spectral sensitivity particularly in the infrared can be used. Preferred examples of the infrared spectral sensitizing dye include infrared spectral sensitizing dyes disclosed in U.S. Pat. Nos. 4,536,473, 4,515,888, and 4,959,294. Can be

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

The above infrared sensitizing dyes are described, for example, in FM Hammer: The Chemistry of Heterocyclic Compounds, Vol. 18, The Cyanine Dyes and Related Documents (A. Weißberger, Germany, ed., 1964). It can be easily synthesized by the method.

These infrared sensitizing dyes may be added at any time after the preparation of the silver halide, for example, by adding them to a solvent or dispersing them into fine particles in a so-called solid dispersion state of silver halide grains or silver halide grains. / A photosensitive emulsion containing silver aliphatic carboxylate particles. Also, like the heteroatom-containing compound having an adsorptivity to the silver halide grains, the chemical sensitization can be performed after adding and adsorbing the silver halide grains prior to the chemical sensitization. Thereby, the dispersion of the chemical sensitization center nucleus can be prevented, and high sensitivity and low fog can be achieved.

分光 The above-mentioned spectral sensitizing dyes may be used alone, or a combination thereof may be used, and a combination of sensitizing dyes is often used particularly for supersensitization.

Emulsions containing photosensitive silver halide and silver aliphatic carboxylate used in photothermographic materials are dyes having no spectral sensitizing effect or substances which do not substantially absorb visible light, together with sensitizing dyes. In this case, a substance exhibiting a supersensitizing 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, IV, J, JP-B 9-25500, JP-B No. 43-4933, JP-A-59-19032, JP-A-59-192242, JP-A-5-341432, and the like. As the supersensitizer, a heteroaromatic mercapto represented by the following is used. Compounds or mercapto derivative compounds are preferred.

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

メ ル In addition, a mercapto derivative compound which substantially forms the above-mentioned mercapto compound when contained in a dispersion of a silver aliphatic carboxylate and / or silver halide grain emulsion is also included. Particularly preferred are the mercapto derivative compounds shown below.

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

The heteroaromatic ring includes, for example, a halogen atom, a hydroxyl group, an amino group, a carboxyl group, an alkyl group (preferably having 1 to 4 carbon atoms) and an alkoxy group (preferably having 1 to 4 carbon atoms). Having an atom).

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

In the formula, H ₃₁ Ar represents an aromatic hydrocarbon group or an aromatic heterocyclic group, T ₃₁ represents a divalent linking group or a linking group consisting of an aliphatic hydrocarbon group, and J ₃₁ represents an oxygen atom or a sulfur atom. Or a divalent linking group or linking group containing at least one nitrogen atom. 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 Ra and Rb, Rc and Rd, Ra and Rc or Rb and Rd, Can combine to form a nitrogen-containing heterocyclic group. M ₃₁ represents an ion necessary to compensate for intramolecular charge, k ₃₁ represents the number of ions necessary to compensate for an intramolecular charge.

Detailed descriptions of the substituents in the general formula [5] can be found in paragraphs “0023” to “0032” of Japanese Patent Application No. 2000-70296, and compound examples in paragraphs “0033” to “0039” are 1-1 to 1-1. -31.

(4) The supersensitizer is preferably used in the photosensitive layer containing the organic silver salt and silver halide grains in an amount of 0.001 to 1.0 mol per mol of silver. Particularly preferably, the amount is 0.01 to 0.5 mol per mol of silver.

に お い て In the present invention, it is preferable to use a silver saving agent. A silver saving agent is a compound that can reduce the amount of silver required to obtain a certain silver image density. Although there are various possible mechanisms for the function of reducing the function, a compound having a function of improving the covering power (covering power) of the developed silver is preferable. Here, the covering power of the developed silver means an optical density per unit amount of silver. This silver saving agent can be present in the photosensitive layer or the non-photosensitive layer, or in both of them.

Preferred examples of the silver saving agent include hydrazine derivatives represented by the following general formula [H], vinyl compounds represented by the general formula [G], and quaternary onium compounds represented by the general formula [P]. .

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

The aliphatic group represented by A ₀ preferably has 1 to 30 carbon atoms, and particularly preferably a straight-chain, branched or cyclic alkyl group having 1 to 20 carbon atoms. The aromatic group represented by A ₀ is preferably a monocyclic or condensed-ring aryl group, and the heterocyclic group includes at least one heteroatom selected from nitrogen, sulfur, and oxygen in a monocyclic or condensed ring. Heterocyclic groups are preferred. Aromatic groups A _0, heterocyclic group or -G ₀ -D ₀ group may have a substituent. Particularly preferred as A ₀ are an aryl group and a —G ₀ -D ₀ group.

A ₀ preferably contains at least one diffusion-resistant group or silver halide-adsorbing group. As the diffusion resistant group, a ballast group commonly used in immobile photographic additives such as couplers is preferable. Examples of the silver halide adsorption accelerating group include thiourea, thiourethane group, mercapto group, thioether group, thione group, heterocyclic group, thioamide heterocyclic group, mercapto heterocyclic group and the adsorption described in JP-A-64-90439. And the like.

The blocking group represented by B ₀ is preferably a -G ₀ -D ₀ group.

<< Details of these substituents are described in paragraphs "0165" to "0170" of Japanese Patent Application No. 2001-263350.

化合物 The compound represented by the general formula [H] can be easily synthesized by a known method. For example, it can be synthesized with reference to U.S. Patent Nos. 5,464,738 and 5,496,695.

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

In the general formula [G], X and R ₄₀ are represented in the form of cis. However, the general formula [G] includes X and R ₄₀ in the form of a trans.

In the general formula [G], X represents an electron-withdrawing group, W represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a heterocyclic group, a halogen atom, an acyl group, a thioacyl group, an oxalyl group, an oxy group. Oxalyl group, thiooxalyl group, oxamoyl group, oxycarbonyl group, thiocarbonyl group, carbamoyl group, thiocarbamoyl group, sulfonyl group, sulfinyl group, oxysulfinyl group, thiosulfinyl group, sulfamoyl group, oxysulfinyl group, thiosulfinyl group, Represents a sulfinamoyl group, a phosphoryl group, a nitro group, an imino group, an N-carbonylimino group, an N-sulfonylimino group, a dicyanoethylene group, an ammonium group, a sulfonium group, a phosphonium group, a pyrylium group or an immonium group.

R ₄₀ represents a halogen atom, a hydroxyl group, an alkoxy group, an aryloxy group, a heterocyclic oxy group, an alkenyloxy group, an acyloxy group, an alkoxycarbonyloxy group, an aminocarbonyloxy group, a mercapto group, an alkylthio group, an arylthio group, or a heterocyclic thio group. Group, alkenylthio group, acylthio group, alkoxycarbonylthio group, aminocarbonylthio group, organic or inorganic salt of hydroxyl group or mercapto group, amino group, alkylamino group, cyclic amino group, acylamino group, oxycarbonylamino group, Represents a 5- to 6-membered heterocyclic group, ureido group or sulfonamide group. X and W, and X and R ₄₀ may be bonded to each other to form a cyclic structure.

す る と To explain further, the electron-withdrawing group represented by X is a substituent whose substituent constant σp can take a positive value.

The details of these substituents are described in paragraphs “0175” to “0178” of Japanese Patent Application No. 2001-263350.

In the general formula [P], Q ₃ represents a nitrogen atom or a phosphorus atom, R ₄₁ , R ₄₂ , R ₄₃ and R ₄₄ each represent a hydrogen atom or a substituent, and X ⁻ represents an anion. Incidentally, R _{41 to} R ₄₄ may be connected to each other to form a ring.

The substituents represented by R _{41 to} R ₄₄ and the ring which R _{41 to} R ₄₄ can form by linking each other are described in paragraphs “0180” to “0183” of Japanese Patent Application No. 2001-263350.

The quaternary onium compound can be easily synthesized according to a known method. For example, the tetrazolium compound can be obtained from Chemical Reviews vol. The method described on pages 55, 335-483 can be referred to. The addition amount of the above silver saving agent is in the range of 10 ^-5 to 1 mol, preferably 10 ^{-4 to} 5 × 10 ^-1 mol, per 1 mol of the silver aliphatic carboxylate.

[6] Binders and Crosslinking Agents Binders suitable for the photothermographic material of the present invention are transparent or translucent and generally colorless, and include natural polymer synthetic resins, polymers and copolymers, and other film-forming media, for example: gelatin, Arabic Rubber, poly (vinyl alcohol), hydroxyethyl cellulose, cellulose acetate, cellulose acetate butyrate, poly (vinyl pyrrolidone), casein, starch, polyacrylic acid, polymethyl methacrylic acid, polyvinyl chloride, polymethacrylic acid, copoly (styrene- Maleic anhydride), copoly (styrene-acrylonitrile), copoly (styrene-butadiene), polyvinylacetals (such as polyvinylformal and polyvinylbutyral), polyesters, polyurethanes, phenoxy resins, and polysalts Examples include vinylidene chloride, polyepoxides, polycarbonates, polyvinyl acetate, cellulose esters, polyamides, and the like. The binder may be hydrophilic or non-hydrophilic.

好 ま し い The preferred binder for the photosensitive layer of the photothermographic material is polyvinyl acetal, and the particularly preferred binder is polyvinyl butyral. Details will be described later. Also, for non-photosensitive layers such as an overcoat layer and an undercoat layer, particularly a protective layer and a back coat layer, a polymer having a higher softening temperature, such as cellulose esters, particularly triacetyl cellulose, and a polymer such as cellulose acetate butyrate. preferable. In addition, if necessary, the above binders may be used in combination of two or more.

Such a binder is used in a range effective to function as a binder. Effective ranges can be readily determined by those skilled in the art. For example, as an index when at least a silver aliphatic carboxylate is retained in the photosensitive layer, the ratio of the binder to the silver aliphatic carboxylate is preferably in the range of 15: 1 to 1: 2. That is, the binder amount of the photosensitive layer is preferably from 1.0 to 10.0 g / m ² . If it is less than 1.0 g / m ² , the density of the unexposed portion will increase significantly and may not be usable.

(4) The binder for the photosensitive layer preferably has a heat transition point of 46 to 200 ° C. after development at a temperature of 100 ° C. or more and 200 ° C. or less. Here, the thermal transition point temperature is determined by using a differential scanning calorimeter (DSC), for example, EXSTAR 6000 (manufactured by Seiko Instruments Inc.), DSC220C (manufactured by Seiko Instruments Inc.), DSC-7 (manufactured by PerkinElmer), or the like. It refers to an endothermic peak when a thermally developed photosensitive layer is isolated and measured. Generally, a polymer compound has a glass transition temperature (Tg), but in a photothermographic material, a large endothermic peak appears at a place lower than the Tg value of a binder resin used for a photosensitive layer. Focusing attention on this heat transition temperature, as a result of intensive studies, it has been found that setting this heat transition temperature to 46 to 200 ° C. not only increases the robustness of the formed coating film, but also increases sensitivity, maximum density, and image quality. Photographic performance such as storage stability is greatly improved.

Tg was determined by the method described in Brand Wrap et al., "Polymer Handbook", pages III-139 to 179 (1966, Wiley & Son, Inc.), and was determined when the binder was a copolymer resin. Tg is obtained by the following equation.

Tg _{(copolymer) (℃) = 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 Represents the Tg (° C.) of the homopolymer obtained from The accuracy of the Tg calculated according to the above equation is ± 5 ° C.

In the photothermographic material of the present invention, a conventionally known polymer compound may be used as a binder contained in a photosensitive layer containing a silver salt of an aliphatic carboxylic acid, photosensitive silver halide particles, a reducing agent, and the like on a support. Can be. It has a Tg of 70 to 105 ° C, a number average molecular weight of 1,000 to 1,000,000, preferably 10,000 to 500,000, and a degree of polymerization of about 50 to 1,000. Specific examples of such a material include vinyl chloride, vinyl acetate, vinyl alcohol, maleic acid, acrylic acid, acrylate, vinylidene chloride, acrylonitrile, methacrylic acid, methacrylate, styrene, butadiene, ethylene, vinyl butyral, There are compounds made of polymers or copolymers containing ethylenically unsaturated monomers such as vinyl acetal and vinyl ether as constituent units, polyurethane resins, and various rubber resins. Further, phenol resins, epoxy resins, polyurethane-curable resins, urea resins, melamine resins, alkyd resins, formaldehyde resins, silicone resins, epoxy-polyamide resins, polyester resins and the like can be mentioned.

樹脂 These resins are described in detail in the Plastic Handbook published by Asakura Shoten. These polymer compounds are not particularly limited, and may be a homopolymer or a copolymer as long as the glass transition temperature (Tg) of the derived polymer is in the range of 70 to 105 ° C.

Examples of the polymer or copolymer containing such an ethylenically unsaturated monomer as a constituent unit include alkyl acrylates, aryl acrylates, alkyl methacrylates, aryl methacrylates, alkyl cyanoacrylates. Esters, aryl cyanoacrylates and the like, and their alkyl groups and aryl groups may be substituted or unsubstituted, and specifically, methyl, ethyl, propyl, i-propyl, butyl, i-butyl, sec-butyl, t-butyl, amyl, hexyl, cyclohexyl, benzyl, chlorobenzyl, octyl, stearyl, sulfopropyl, N-ethyl-phenylaminoethyl, 2- (3-phenylpropyloxy) ethyl, dimethyl Aminophenoxyethyl Furfuryl, tetrahydrofurfuryl, phenyl, cresyl, naphthyl, 2-hydroxyethyl, 4-hydroxybutyl, triethylene glycol, dipropylene glycol, 2-methoxyethyl, 3-methoxybutyl, 2-acetoxyethyl, 2-acetoacetoxyethyl , 2-ethoxyethyl, 2-i-propoxyethyl, 2-butoxyethyl, 2- (2-methoxyethoxy) ethyl, 2- (2-ethoxyethoxy) ethyl, 2- (2-butoxyethoxy) ethyl, 2- Examples thereof include diphenylphosphorylethyl, ω-methoxypolyethylene glycol (additional mole number n = 6), allyl, dimethylaminoethylmethyl chloride salt and the like.

In addition, the following monomers can be used. Vinyl esters: vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl caproate, vinyl chloroacetate, vinyl methoxy acetate, vinyl phenyl acetate, vinyl benzoate, vinyl salicylate, etc .; N-substituted acrylamide , N-substituted methacrylamides and acrylamide, methacrylamide: N-substituents include methyl, ethyl, propyl, butyl, tert-butyl, cyclohexyl, benzyl, hydroxymethyl, methoxyethyl, dimethylaminoethyl, phenyl, dimethyl , Diethyl, β-cyanoethyl, N- (2-acetoacetoxyethyl), diacetone, etc .; olefins: dicyclopentadiene, ethylene, propylene, 1-butene, 1-pentene, vinyl chloride Vinylidene chloride, isoprene, chloroprene, butadiene, 2,3-dimethylbutadiene and the like; styrenes: methylstyrene, dimethylstyrene, trimethylstyrene, ethylstyrene, isopropylstyrene, t-butylstyrene, chloromethylstyrene, methoxystyrene, acetoxystyrene, Chlorostyrene, dichlorostyrene, bromostyrene, methyl vinyl benzoate, etc .; vinyl ethers: methyl vinyl ether, butyl vinyl ether, hexyl vinyl ether, methoxyethyl vinyl ether, dimethylaminoethyl vinyl ether, etc .; N-substituted maleimides: as N-substituents , Methyl, ethyl, propyl, butyl, t-butyl, cyclohexyl, benzyl, dodecyl, phenyl, 2-methylphenyl, 2,6- Those having diethylphenyl, 2-chlorophenyl, and the like; and others, butyl crotonate, hexyl crotonate, dimethyl itaconate, dibutyl itaconate, diethyl maleate, dimethyl maleate, dibutyl maleate, diethyl fumarate, fumaric acid, and the like. Dimethyl, dibutyl fumarate, methyl vinyl ketone, phenyl vinyl ketone, methoxyethyl vinyl ketone, glycidyl acrylate, glycidyl methacrylate, N-vinyloxazolidone, N-vinylpyrrolidone, acrylonitrile, methacrylonitrile, methylenemalononitrile, vinylidene chloride, and the like. Can be.

Of these, particularly preferred examples include alkyl methacrylates, aryl methacrylates, and styrenes. Among such polymer compounds, it is preferable to use a polymer compound having an acetal group. A polymer compound having an acetal group has excellent compatibility with the aliphatic carboxylic acid to be generated, and therefore has a large effect of preventing the film from being softened, and thus is preferable.

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

In the formula, R ₅₁ represents an alkyl group, a substituted alkyl group, an aryl group or a substituted aryl group, and is preferably a group other than the 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 . a, b, and c are values in which the mass of each repeating unit is represented by mol (mol)%, a is 40 to 86 mol%, b is 0 to 30 mol%, and c is 0 to 60 mol%. Represents a number that satisfies a + b + c = 100 mol%.

<< Details of these substituents are described in paragraphs "0199" to "0201" of Japanese Patent Application No. 2001-263350.

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 polyurethane shown here, if _{necessary, -COOM, -SO 3 M, -OSO} 3 M, -P = O (OM) 2, -O-P = O (OM) 2 (M is a hydrogen atom or an alkali metal _{base), - N (R 54)} 2, -N + (R 54) 3 (R 54 represents a hydrocarbon group, the plurality of R ₅₄ may be the same or different), an epoxy group, It is preferable to use one obtained by introducing at least one or more polar groups selected from -SH, -CN and the like by copolymerization or addition reaction. The amount of such a polar group is from 10 ^-1 to 10 ^-8 mol / g, preferably from 10 ^-2 to 10 ^-6 mol / g. In addition to these polar groups, it is preferable to have at least one hydroxyl group at the terminal of the polyurethane molecule, that is, a total of two or more hydroxyl groups. Since a hydroxyl group crosslinks with a polyisocyanate as a curing agent to form a three-dimensional network structure, it is preferable to include a large number of hydroxyl groups in a molecule. In particular, it is preferable that the hydroxyl group be located at the molecular terminal because the reactivity with the curing agent is high. The polyurethane preferably has three or more hydroxyl groups at the molecular terminals, and particularly preferably four or more hydroxyl groups. 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 [V] can be synthesized by a general synthesis method described in "Vinyl acetate resin" edited by Ichiro Sakurada (Polymer Chemistry Publishing Association, 1962).

These polymer compounds may be used alone as a binder, or two or more of them may be used as a blend. The above polymer is used as a main binder in the photosensitive silver salt-containing layer (preferably the photosensitive layer) of the present invention. The main binder as used herein means "the state in which the polymer accounts for 50% by mass or more of the total binder in the photosensitive silver salt-containing layer". Therefore, other polymers may be blended and used in a range of less than 50% by mass of the total binder. These polymers are not particularly limited as long as they are solvents in which the polymer of the present invention is soluble. More preferably, polyvinyl acetate, polyacrylic resin, urethane resin and the like can be mentioned.

Table 1 below shows the constitution of the polymer compound preferably used in the present invention. Tg in the table is a value measured by a differential scanning calorimeter (DSC) manufactured by Seiko Instruments Inc. In addition, P-9 is a polyvinyl butyral resin B-79 manufactured by Sorcia.

は It is known that the use of a cross-linking agent with respect to the binder improves the film formation and reduces development unevenness.

Examples of the crosslinking agent used include various crosslinking agents conventionally used for silver halide photographic light-sensitive materials, for example, aldehyde-based, epoxy-based, ethyleneimine-based and isocyanate-based compounds described in JP-A-50-96216. <Vinyl sulfone type, sulfonate type, acryloyl type, carbodiimide type, silane compound type cross-linking agent may be used, but in the present invention, at least one of the cross-linking agents is preferably a polyfunctional carbodiimide type compound.

The carbodiimide-based crosslinking agent is a compound having at least two carbodiimide groups and an adduct thereof (adduct). More specifically, aliphatic dicarbodiimides and aliphatic dicarbodiimides having a cyclic group , Benzenedicarbodiimides, naphthalenedicarbodiimides, biphenylcarbodiimides, diphenylmethanedicarbodiimides, triphenylmethanedicarbodiimides, tricarbodiimides, tetracarbodiimides, and adducts of these carbodiimides and these carbodiimides Adducts with dihydric or trihydric polyalcohols may be mentioned. Such carbodiimides can be produced by reacting the corresponding isocyanates with a primary amine in the presence of a phosphorus catalyst, for example, a phosphorene compound.

The polyfunctional carbodiimide compound is a compound having two or more carbodiimide groups or carbodithioimide groups in the molecular structure. More preferably, it is a polyfunctional aromatic carbodiimide compound, which is a compound having a carbodiimide group and an aromatic group in the molecular structure.

General formula (CI)
R ₁ −J ₁ −N = C = N−J ₂ − (L) _n − (J ₃ −N = C = N−J ₄ −R ₂ ) _v
As the polyfunctional carbodiimide compound, any compound having a bifunctional or more carbodiimide group can be preferably used, and particularly preferably a compound having the structure of the general formula (CI).

In the general formula (CI), examples of the alkyl group and aryl group represented by R ₁ and R ₂ include, for example, methyl, ethyl, propyl, butyl, and pentyl groups as the alkyl group, and benzene as the aryl group. , Naphthalene, toluene, xylene, etc., and the heterocyclic group is a residue of furan, thiophene, dioxane, pyridine, piperazine, morpholine, etc., and these groups are groups linked by a linking group. You may.

The linking group represented by J ₁ or J ₄ represents a linking group formed from an oxygen atom, a nitrogen atom, a sulfur atom, a phosphorus atom, or the like, which may be a simple bond or may include a carbon atom. S, NH, CO, COO, SO, SO ₂ , NHCO, NHCONH, PO, PS and the like. Examples of the alkylene group or arylene group represented by J ₂ and J ₃ include an alkylene group such as methylene, ethylene, trimethylene, tetramethylene, and hexamethylene; and an arylene group such as phenylene, tolylene, and naphthalene.

The (v + 1) -valent alkyl group represented by L includes methyl, ethyl, propyl, butyl, pentyl and the like, the alkenyl group includes ethenyl, propenyl, butadiene, pentadiene and the like, and the aryl group includes benzene , Naphthalene, toluene, xylene and the like, and the heterocyclic group is a residue of furan, thiophene, dioxane, pyridine, piperazine, morpholine and the like, and these groups may be a group bonded by a linking group. . The linking group represents a linking group formed from an oxygen atom, a nitrogen atom, a sulfur atom, a phosphorus atom, or the like, which may be a simple bond or may include a carbon atom, for example, O, S, NH, CO, SO, SO ₂ , NHCO, NHCONH, PO, PS and the like. The integer of 1 or more represented by v is preferably an integer of 1 to 6, and more preferably 1, 2 or 3.

具体 Specific examples of the crosslinking agent of the present invention represented by the general formula (CI) are shown below.

The polyfunctional carbodiimide crosslinking agent may be added to any part of the photothermographic material. For example, the support (especially when the support is paper, can be included in the size composition), 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. Can be added to any of these layers, and can be added to one or more of these layers.

The amount of the crosslinking agent is 0.001 to 2 mol, preferably 0.005 to 1 mol, per 1 mol of silver. Two or more kinds may be used in combination within this range.

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

エ ポ キ シ Epoxy compounds that can be used as a crosslinking agent may be compounds having at least one epoxy group, and there is no limitation on the number, molecular weight, and the like of epoxy groups. The epoxy group is preferably contained in the molecule as a glycidyl group via an ether bond or an imino bond. The epoxy compound may be any of a monomer, oligomer, polymer and the like, and the number of epoxy groups present in the molecule is usually about 1 to 10, preferably 2 to 4. When the epoxy compound is a polymer, it may be either a homopolymer or a copolymer, and a particularly preferred range of the number average molecular weight Mn is about 2,000 to 20,000.

As the epoxy compound, a compound represented by the general formula [9] described in Japanese Patent Application No. 2001-263350 is preferable.

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 may be one having at least one such acid anhydride group, and there is no limitation on the number, molecular weight, and the like of the acid anhydride group, but the general formula [B] described in Japanese Patent Application No. 2001-263350. The compounds represented are preferred.

(7) Other Additives The photothermographic material of the present invention forms a photographic image by thermal development, and includes a reducible silver source (silver aliphatic carboxylate), photosensitive silver halide particles, It is usually preferable that the composition contains an agent and, if necessary, a color tone agent for adjusting the color tone of silver in a state of being dispersed in an (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. Particularly preferred toning agents are phthalazinone or a combination of phthalazine with phthalic acid or phthalic anhydride.

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

Terminology of color "more Hiyacho" and "more temperature control" is determined by the hue angle h _ab defined by JIS Z 8729 in the minimum density Dmin and optical density D = 1.0. Hue angle h _ab is JIS Z 8701 to regulatory XYZ color system or tristimulus values X, Y, Z or X _10, Y _10, L is defined from the Z ₁₀ in JIS Z 8729 ^* a ^* b ^* color system Can be represented by _hab = tan ^- 1 (b ^* / a ^* ) using the color coordinates a ^* and b ^* .

The terms "cooler tone" and "hoter tone" in terms of color tone refer to the horizontal axis u ^* or a ^{* in the} CIE 1976 (L ^* u ^* v ^* ) or (L ^* a ^* b ^* ) color space ^. When plotting u ^* , v ^* or a ^* , b ^* at various photographic densities on a graph with the vertical axis representing v ^* or b ^* to create a linear regression line (y = ax + b), The slope (a) of the linear regression line is 0.5 to 1.5, preferably 0.75 to 1.25, the intercept b is -3 or more and 3 or less, more preferably -1 or more and 1 or less. R2) is adjusted to be in the range of 0.8000 or more and 1.0000 or less, preferably 0.9000 or more and 1.000 or less, in the low-density part to the medium-density part of the diagnostic photograph, especially in the lung field part mediastinum part. It has excellent recognizability and has a diagnostic performance equal to or better than that of conventional wet silver halide photosensitive materials. .

こ と By doing so, the recognizability of the low-density part of the diagnostic photograph, particularly the lung mediastinal part, is improved.

In the present invention, in the surface layer of the photothermographic material (even in the case where a non-photosensitive layer is provided on the photosensitive layer side or on the side opposite to the photosensitive layer with the support interposed therebetween), handling before development and image formation after thermal development are performed. It is preferable to contain a matting agent in order to prevent damage to the binder, and the content is 0.1 to 30% by mass relative to the binder.

The material of the matting agent may be either an organic substance or an inorganic substance. For example, inorganic substances include silica described in Swiss Patent No. 330,158, glass powder described in French Patent No. 1,296,995, etc., and alkaline earth metal described in British Patent No. 1,173,181 and the like. Alternatively, carbonates such as cadmium and zinc can be used as a matting agent. Examples of organic substances include starch described in U.S. Pat. No. 2,322,037, starch derivatives described in Belgian Patent 625,451 and British Patent 981,198, etc., and polyvinyl described in Japanese Patent Publication No. 44-3643. Alcohols, such as polystyrene or polymethacrylate described in Swiss Patent No. 330,158, polyacrylonitrile described in U.S. Pat. No. 3,079,257, and polycarbonate described in U.S. Pat. No. 3,022,169. Organic matting agents 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 matting agent preferably has a variation coefficient of the particle size distribution of 50% or less, more preferably 40% or less, 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 in a coating liquid in advance, or a method in which the matting agent is sprayed before the drying is completed after applying the coating liquid. You may. When a plurality of types of matting agents are added, both methods may be used in combination.

(8) Support Materials for the support material used for the photothermographic material include various polymer materials, glass, wool cloth, cotton cloth, paper, metal (aluminum, etc.), and the like. Is preferably a material that can be processed into a flexible sheet or roll. Accordingly, the support in the photothermographic material of the present invention is preferably a plastic film (cellulose acetate, polyester, polyethylene terephthalate, polyethylene naphthalate, polyamide, polyimide, cellulose triacetate or polycarbonate film, etc.). Particularly preferred is a polyethylene terephthalate (PET) film. The thickness of the support is about 50 to 300 μm, preferably 70 to 180 μm.

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

(9) Layer Structure and Production Method of Photothermographic Material The photothermographic material of the present invention has at least one photosensitive layer on a support. Although only the photosensitive layer may be formed on the support, it is preferable to form at least one non-photosensitive layer on the photosensitive layer. For example, a protective layer is provided on the photosensitive layer for the purpose of protecting the photosensitive layer, and on the opposite side of the support, to prevent sticking between photosensitive materials or in a photosensitive material roll, Preferably, a layer is provided.

As a binder used for these protective layer and back coat layer, a glass transition point is higher than that of the heat-developing layer, and abrasion or a polymer that hardly deforms, for example, a polymer such as cellulose acetate or cellulose acetate butyrate, is used as the binder. Selected from In addition, two or more photosensitive layers may be provided on one side of the support, or one or more layers may be provided on both sides of the support, for gradation adjustment or the like.

In photothermographic materials, it is possible to form a filter layer on the same side as the photosensitive layer or on the opposite side to control the amount or wavelength distribution of light transmitted through the photosensitive layer, or to include a dye or pigment in the photosensitive layer. preferable. As the dye to be used, known compounds that absorb light in various wavelength ranges according to the color sensitivity of the photosensitive material can be used. For example, when the photothermographic material of the present invention is used as an image recording material by infrared light, a squarylium dye having a thiopyrylium nucleus and a squarylium dye having a pyrylium nucleus as disclosed in Japanese Patent Application No. 11-255557, It is also preferable to use a thiopyrylium croconium dye similar to a squarylium dye or a pyrylium croconium dye.

The compound having a squarylium nucleus is a compound having 1-cyclobuten-2-hydroxy-4-one in a molecular structure, and the compound having a croconium nucleus is a compound having 1-cyclopenten-2-hydroxy-one in a molecular structure. It is a compound having 4,5-dione. Here, the hydroxyl group may be dissociated.

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

(4) The photothermographic material is preferably formed by preparing a coating solution in which the above-described constituent layer materials are dissolved or dispersed in a solvent, applying a plurality of these coating solutions at the same time, and then performing a heat treatment. Here, “multi-layer coating at the same time” means that a coating solution for each constituent layer (for example, a photosensitive layer and a protective layer) is prepared, and when the coating solution is applied to a support, coating and drying are repeated for each layer individually. In other words, it means that each constituent layer can be formed in a state where the steps of simultaneously performing multi-layer coating and drying can be performed at the same time. That is, the upper layer is provided before the remaining amount of all the solvents in the lower layer becomes 70% by mass or less.

There is no particular limitation on the method of simultaneously applying multiple layers of each constituent layer, for example, using a known method such as a bar coater method, a curtain coat method, an immersion method, an air knife method, a hopper application method, or an extrusion application method. Can be. Among these, a pre-metering type coating method called an extrusion coating method is more preferable. The extrusion coating method is suitable for precision coating and organic solvent coating because there is no volatilization on the slide surface unlike the slide coating method. Although this coating method has been described on the side having the photosensitive layer, the same applies to the case where the backcoat layer is provided and the coating is performed together with the undercoating.

It is preferable to select an appropriate amount of the applied silver according to the purpose of the photothermographic material. In the present invention, the amount is preferably 0.5 to 1.5 g / m ² . It is more preferably from 0.6 to 1.4 g / m ² , and particularly preferably from 1.0 to 1.3 g / m ² . Of the coated silver amount, the amount derived from silver halide preferably accounts for 2 to 18% of the total silver mass, and more preferably 3 to 15%.

In the present invention, the coating density of silver halide grains having a particle size of 0.01 μm or more (equivalent sphere equivalent diameter) is preferably 1 × 10 ¹⁴ to 1 × 10 ¹⁸ grains / m ² . Further, the density is preferably 1 × 10 ¹⁵ to 1 × 10 ¹⁷ pieces / m ² .

Furthermore, the coating density of the aliphatic carboxylic acid silver salt is 10 ^-17 to 10 ^-15 g, and more preferably 10 ^-16 to 10 ^-14 g per silver halide grain having a particle size of 0.01 μm or more (equivalent sphere size). Is preferred. When the coating is performed under the conditions within such a range, a preferable result is obtained from the viewpoints of the optical maximum density of the silver image per a fixed amount of silver applied, that is, the silver coating amount (covering power) and the color tone of the silver image. Is obtained.

(10) Image Forming Apparatus In the present invention, the developing conditions vary depending on the equipment, apparatus, or means used, but typically, heating the photothermographic material imagewise exposed at a suitable high temperature. Accompanied by The latent image obtained after exposure can be developed by heating the photothermographic material at moderately elevated temperatures (80-200 ° C, preferably 100-200 ° C) for a sufficient time (typically 1 second to 2 minutes). If the heating temperature is lower than 80 ° C, a sufficient image density cannot be obtained in a short time, and if the heating temperature exceeds 200 ° C, the binder is melted and transferred not only to the image itself such as transfer to a roller, but also to transportability and a developing machine. Also have an adverse effect. By heating, a silver image is generated by an oxidation-reduction reaction between a silver aliphatic carboxylate (functioning as an oxidizing agent) and a reducing agent. This reaction process proceeds without any supply of a processing liquid such as water from the outside.

機器 The equipment, apparatus and means for heating may be performed by a typical heating means such as a hot plate, an iron, a hot roller, a heat generator using carbon or white titanium or the like. More preferably, the photothermographic material provided with the protective layer according to the present invention, the heat treatment by contacting the surface on the side having the protective layer with a heating means, in order to perform uniform heating, thermal efficiency, It is preferable from the viewpoint of workability and the like, and it is preferable that the surface is conveyed while being in contact with a heat roller, heated, and developed.

It is desirable to use a light source appropriate for the exposure of the photothermographic material to the color sensitivity imparted to the photosensitive material. For example, when the photosensitive material can be sensed by infrared light, the light-sensitive material can be applied to any light source in the infrared light region, but the laser power can be high or the photosensitive material can be made transparent. From these points, 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.

{Circle around (1)} As a first preferred method, there is a method using a laser scanning exposure machine in which the angle between the exposure surface of the photosensitive material and the scanning laser beam does not become substantially perpendicular. Here, “not substantially perpendicular” means that the angle is most perpendicular during laser scanning, preferably 55 to 88 °, more preferably 60 to 86 °, and still more preferably 65 to 84 °. , Most preferably 70-82 °.

ビ ー ム The beam spot diameter on the exposed surface of the photosensitive material when the laser light is scanned on the photosensitive material is preferably 200 µm or less, more preferably 100 µm or less. It is preferable that the spot diameter is small in that the shift angle of the laser incident angle from the perpendicular can be reduced. Note that 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 due to reflected light such as the occurrence of interference fringe-like unevenness.

As a second method, it is preferable that the exposure in the present invention is performed using a laser scanning exposure machine that emits a scanning laser beam that is a vertical multi. Image quality deterioration such as generation of interference fringe-like unevenness is reduced as compared with the scanning laser beam in the longitudinal single mode.

To achieve vertical multiplication, it is preferable to use return light due to multiplexing or to apply high frequency superposition. In addition, 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, as a laser used for scanning exposure, a well-known solid laser such as a ruby laser, a YAG laser, or a glass laser; a He / Ne laser; Gas lasers such as Ar ion laser, Kr ion laser, CO ₂ laser, CO laser, He · Cd laser, N ₂ laser, excimer laser; In · Ga · P laser, Al · Ga · As laser, Ga · As · P can be used by appropriately selected in conjunction chemical laser, a dye laser or the like on the application; laser, in · Ga · As laser, in · As · P laser, Cd · Sn · P ₂ laser, a semiconductor laser of Ga · Sb laser, However, among these, it is preferable to use a semiconductor laser having a wavelength of 600 to 1200 nm from the viewpoint of maintenance and the size of the light source. Incidentally, in a laser used in a laser imager or a laser imagesetter, the beam spot diameter on the exposed surface of a photothermographic material when it is scanned is generally 5 to 75 μm as a short axis diameter, and a long axis diameter. The scanning speed of the laser beam can be set to an optimum value for each photosensitive material by the sensitivity and laser power at the laser oscillation wavelength inherent to the photothermographic material.

The heat development apparatus according to the present invention includes a film supply unit represented by a film tray, a laser image recording unit, a heat development unit that supplies uniform and stable heat to the entire surface of the photothermographic material, and a film supply unit. From the laser recording to the heat development photosensitive material on which an image has been formed by heat development until it is discharged out of the apparatus. FIG. 1 shows a cross-sectional configuration diagram illustrating an example of the thermal development processing apparatus of this embodiment.

The thermal developing device 100 includes a feeding unit 110 that feeds a sheet-like photothermographic material (also simply referred to as a film) one by one, an exposing unit 120 that exposes the fed film F, The developing unit 130 includes a developing unit 130 for developing, a cooling unit 150 for stopping the development, and a stacking unit 160. 151 is a pair of cooling rollers, and 152 is a cooling fan. A pair of supply rollers 140 for supplying the film F from the supply unit, a pair of supply rollers 144 for feeding the film to the developing unit, and a pair of transport rollers 141, 142, 143 for smoothly transferring the film F between the respective units. It consists of multiple roller pairs. The heat developing section is a heating means for developing the film F. The heat drum 1 having a plurality of opposed rollers 2 which can be heated while being held almost in close contact with the outer periphery, and the peeling for peeling the developed film F and sending it to the cooling section. It consists of nails 6 and the like.

The transport speed of the photothermographic material is preferably in the range of 20 to 200 mm / sec. The cooling rate in the cooling section is preferably 3 to 20 ° C.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited thereto. Unless otherwise specified, “%” in the examples indicates “% by mass”.

Example 1
<< Preparation of support >>
One side of a 175 μm-thick polyethylene terephthalate (PET) film base, which is colored blue and has a concentration of 0.170, is subjected to a corona discharge treatment of 0.5 kV · A · min / m ² , and then the following undercoating is performed. Using the coating liquid A, the undercoat layer a was applied so that the dry film thickness was 0.2 μm. Further, the other surface is similarly subjected to a corona discharge treatment of 0.5 kV · A · min / m ² , and then a subbing layer b is formed thereon using a subbing coating solution B described below to form a dry film. The coating was performed so that the thickness became 0.1 μm. Thereafter, heat treatment was performed at 130 ° C. for 15 minutes in a heat treatment oven having a film transport device including a plurality of roll groups.

(Undercoating liquid A)
270 g of a copolymer latex liquid (solid content 30%) of butyl acrylate / t-butyl acrylate / styrene / 2-hydroxyethyl acrylate (30/20/25/25%), 0.6 g of surfactant (UL-1) And 0.5 g of methylcellulose. Further, 1.3 g of silica particles (Syloid 350: manufactured by Fuji Silysia Ltd.) was added to 100 g of water, and dispersion treatment was performed for 30 minutes with an ultrasonic dispersing machine (manufactured by ALEX Corporation: Ultrasonic Generator, frequency 25 kHz, 600 W). , And finally finished to 1000 ml with water to obtain a subbing coating solution A.

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

(Undercoating solution B)
2. 37.5 g of the above colloidal tin oxide dispersion, a copolymer latex liquid (solid content: 30%) of butyl acrylate / t-butyl acrylate / styrene / 2-hydroxyethyl acrylate (20/30/25/25%). 7 g, 14.8 g of a copolymer latex liquid (solid content 30%) of butyl acrylate / styrene / glycidyl methacrylate (40/20/40%) and 0.1 g of a surfactant (UL-1) were mixed, and mixed with water. It was finished to 1000 ml to give a subbing coating solution B.

<< Back side coating >>
While stirring 830 g of methyl ethyl ketone (MEK), 84.2 g of cellulose acetate butyrate (CAB381-20 manufactured by Eastman Chemical) and 4.5 g of a polyester resin (Vitel PE2200B manufactured by Bostic) were added and dissolved. Next, 0.30 g of infrared dye 1, 4.5 g of fluorine-based activator-1 and 1.5 g of fluorine-based activator (manufactured by JEMCO: F-Top EF-105) were added to the dissolved solution, and further, 43.2 g of methanol was added and sufficiently stirred until dissolved. Finally, 75 g of silica particles (Fuji Silysia Co., Ltd .: Sylysia 450) dispersed in MEK at a concentration of 1% with a dissolver type homogenizer were added and stirred to prepare a coating liquid for the back surface side.

Fluorinated activator-1: C ₉ F ₁₇ O (CH ₂ CH ₂ O) ₂₂ C ₉ F ₁₇
The coating solution for the back surface thus prepared was applied and dried on the surface on which the undercoat layer b was applied by an extrusion coater so that the dry film thickness became 3.5 μm. Drying was performed for 5 minutes using a drying air having a drying temperature of 100 ° C. and a dew point temperature of 10 ° C.

<< Preparation of photosensitive silver halide emulsion A >>
Solution (A1)
88.3 g of phenylcarbamoylated gelatin
Activator A (10% methanol aqueous solution) 10 ml
Potassium bromide 0.32g
Solution to be finished to 5429 ml with water (B1)
0.67mol / L silver nitrate aqueous solution 2635ml
Solution (C1)
Potassium bromide 51.55 g
1.47 g of potassium iodide
Solution to be finished to 660 ml with water (D1)
Potassium bromide 154.9g
4.41 g of potassium iodide
Solution (E1) to make up to 1982 ml with water
0.4 mol / L aqueous solution of potassium bromide Solution of the following silver potential control amount (F1)
Potassium hydroxide 0.71g
Solution to be finished to 20 ml with water (G1)
56% acetic acid aqueous solution 18.0ml
Solution (H1)
1.72 g of anhydrous sodium carbonate
Finishing with water to 151 ml A: HO (CH ₂ CH ₂ O) _n [CH (CH ₃ ) CH ₂ O] ₁₇ (CH ₂ CH ₂ O) _m H
(M + n = 5-7)
Using a mixing stirrer described in JP-B-58-58288 and JP-B-58-58289, 1/4 of the solution (B1) and the entire amount of the solution (C1) were added to the solution (A1) at a temperature of 30 ° C. and a pAg of 8.09. The mixture was added by a simultaneous mixing method over 4 minutes and 45 seconds to form nuclei. One minute later, the entire amount of the solution (F1) was added. During this time, the pAg was appropriately adjusted using the aqueous solution (E1). After a lapse of 6 minutes, 3/4 of the solution (B1) and the entire amount of the solution (D1) were added over 14 minutes and 15 seconds by a double jet method while controlling the temperature to 30 ° C. and the pAg to 8.09. After stirring for 5 minutes, the temperature was lowered to 40 ° C., and the whole amount of the solution (G1) was added to precipitate a silver halide emulsion. The supernatant was removed except for 2000 ml of the sedimented portion, 10 L of water was added, and after stirring, the silver halide emulsion was sedimented again. The supernatant was removed, leaving 1500 ml of the sedimented portion, 10 L of water was further added and the mixture was stirred, and the silver halide emulsion was sedimented. After removing the supernatant liquid leaving 1500 ml of the sedimented portion, 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 as to be 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 variation coefficient of grain size 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 a gold sensitizer Au-5 equivalent to 1/20 mol of the sensitizer was further added. For 120 minutes for chemical sensitization. This is designated as photosensitive silver halide emulsion A.

<Organic silver analysis method>
The silver behenate content is determined as follows. Approximately 10 mg of the organic silver salt is accurately weighed and placed in a 200 ml eggplant-type Kolben. 15 ml of methanol and 3 ml of 4 mol / l hydrochloric acid are added and ultrasonically dispersed for 1 minute. Add Teflon (R) zeolite and reflux for 60 minutes. After cooling, 5 ml of methanol is added from above the cooled product, and the substance adhering to the cooling tube is washed into an eggplant-type Kolben (twice). The obtained reaction solution is extracted with ethyl acetate (liquid separation is performed twice by adding 100 ml of ethyl acetate and 70 ml of water). Vacuum dry for 30 minutes. 1 ml of benzanthrone solution (internal standard) is placed in a 10 ml measuring flask. Dissolve the sample in toluene, put it in a volumetric flask and make up with toluene. This is measured by GC, the mol% from the peak area of each organic acid is determined, and the composition of all the organic acids can be known by determining the mass%.

定量 Continue to determine the amount of free organic acids that are not converted to organic silver salts. About 20 mg of the organic silver salt sample is accurately weighed, and 10 ml of methanol is added thereto, followed by ultrasonic dispersion for 1 minute. It is filtered and the filtrate is dried to extract free organic acids. Hereinafter, the composition of the free organic acid and the ratio to the total organic acid can be known by measuring with GC in the same manner as in the case of the whole organic acid. The amount obtained by subtracting the free organic acid from the total organic acid was defined as the composition of the organic acid present as an organic silver salt.

<Preparation of powdered organic silver salt A containing silver halide particles>
Organic silver salt particles were prepared using a commercially available reagent of unpurified behenic acid. When this behenic acid was analyzed by the aforementioned analysis method, the behenic acid content was 80% by mass. Since the rest contained arachidic acid and stearic acid, 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 prepared using the reagents of arachidic acid, stearic acid and palmitic acid. Each of the organic acid reagents was mixed, and poured into 4720 ml of pure water and dissolved at 80 ° C. Next, 540.2 ml of a 1.5 mol / l sodium hydroxide aqueous solution was added, 6.9 ml of concentrated nitric acid was added, and the mixture was cooled to 55 ° C. to obtain a mixed fatty acid sodium solution. While keeping the temperature of the mixed fatty acid sodium solution at 55 ° C. in a state where the light is blocked (hereinafter, the state where the light is blocked), 45.3 g of the silver halide emulsion A and 450 ml of pure water are added. Stirred for minutes. Next, 702.6 ml of a 1 mol / l silver nitrate aqueous solution was added over 2 minutes, and the mixture was stirred for 10 minutes to obtain a silver halide particle-containing organic silver salt particle dispersion A. Thereafter, the obtained silver halide particle-containing organic silver salt particle dispersion A is transferred to a washing vessel, deionized water is added thereto, and the mixture is stirred and allowed to stand to float the silver halide particle-containing organic silver salt particle dispersion A. Separate and remove the lower water-soluble salts. Thereafter, washing with deionized water and draining were repeated until the conductivity of the waste water reached 2 μS / cm, and centrifugal dehydration was performed to obtain cake-like organic silver salt particles A containing silver halide particles. The organic silver salt particles A containing the silver halide particles in the form of cake were dried at a water content of 0 using an air-flow drier flash jet drier (manufactured by Seishin Enterprise Co., Ltd.) according to the operating conditions of the nitrogen gas atmosphere and the hot air temperature at the dryer entrance. Drying was carried out to 0.1% to obtain a powdered organic silver salt A containing silver halide particles. An infrared moisture meter was used to measure the water content of the organic silver salt A containing the silver halide particles. The amount of behenic acid in the powdered organic silver salt A containing silver halide particles was quantified by the above-mentioned analysis method, and the ratio of silver behenate contained in the organic silver salt particles A was 54% by mass. The results of analysis of the mixed organic acids were as follows: the heavy metal content was 5 ppm, and the iodine value was 1.5.

<< Preparation of Preliminary Dispersion A >>
Dissolve 14.57 g of polymer P-9 in 1457 g of MEK, and slowly add 500 g of the above-mentioned powdered organic silver salt A while stirring with a dissolver DISPERMAT CA-40M manufactured by VMA-GETZMANN, and mix well. Thus, a preliminary dispersion A was prepared.

<< Preparation of photosensitive emulsion dispersion A >>
A media type disperser DISPERMAT filled with 0.5 mm diameter zirconia beads (Toray Co., Ltd .: Treceram) so that the pre-dispersion liquid A has a residence time in the mill of 1.5 minutes using a pump so as to have an inner volume of 80%. It was supplied to SL-C12EX type (manufactured by VMA-GETZMANN) and dispersed at a mill peripheral speed of 8 m / sec to prepare a photosensitive emulsion dispersion A.

<< Preparation of stabilizer solution >>
1.0 g of Stabilizer-1 and 0.31 g of potassium acetate were dissolved in 4.97 g of methanol to prepare a stabilizer solution.

<< Preparation of infrared sensitizing dye solution A >>
19.2 mg of infrared sensitizing dye-1, 1.488 g of 2-chloro-benzoic acid, 2.779 g of stabilizer-2 and 365 mg of 5-methyl-2-mercaptobenzimidazole were added to 31.3 ml of MEK Was dissolved in a dark place to prepare an infrared sensitizing dye solution A.

<< Preparation of additive liquid a >>
As a developer, 27.98 g of 1,1-bis (2-hydroxy-3,5-dimethylphenyl) -3,5,5-trimethylhexane (Comparative-1), 1.54 g of 4-methylphthalic acid, and 0.1. 48 g of the infrared dye 1 was dissolved in 110 g of MEK to prepare an additive liquid 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 prepare an additive liquid b.

<< Preparation of photosensitive layer coating solution A >>
In an inert gas atmosphere (nitrogen 97%), the photosensitive emulsion dispersion A (50 g) and 15.11 g of MEK were kept at 21 ° C. while stirring, and 390 μl of antifoggant-1 (10% methanol solution) was added. And stirred for 1 hour. Further, 494 μl of calcium bromide (10% methanol solution) was added, and the mixture was stirred for 20 minutes. Then, after adding 167 ml of stabilizer liquids and stirring for 10 minutes, 1.32 g of the said infrared sensitizing dye liquid A was added and stirred for 1 hour. Thereafter, the temperature was lowered to 13 ° C., and the mixture was further stirred for 30 minutes. While keeping the temperature at 13 ° C., 13.31 g of polymer P-9 was added as a binder resin and stirred for 30 minutes. Then, 1.084 g of tetrachlorophthalic acid (9.4 mass% MEK solution) was added and stirred for 15 minutes. did. While further stirring, 12.43 g of the additive solution a, 1.6 ml of Desmodur N3300 / Mobay's aliphatic isocyanate (10% MEK solution), and 4.27 g of the additive solution b were sequentially added and stirred, followed by exposure. A layer coating solution A was obtained.

<< Preparation of matting agent dispersion >>
7.5 g of cellulose acetate butyrate (CAB171-15, manufactured by Eastman Chemical Company) is dissolved in 42.5 g of MEK, and 5 g of silica particles (Thyricia 320, manufactured by Fuji Silysia Ltd.) are added thereto. The mixture was dispersed at 8000 rpm for 30 minutes to prepare a matting agent dispersion.

構造 The structure of the material used to prepare each additive solution is shown.

<< Preparation of coating solution for surface protective layer >>
While stirring 865 g of MEK, 96 g of cellulose acetate butyrate (CAB171-15: supra), 4.5 g of polymethyl methacrylic acid (Rohm & Haas: Paraloid A-21), 1.0 g of benzotriazole, fluorine 1.0 g of a surfactant (manufactured by GEMCO: F-Top EF-105) was added and dissolved. Next, 30 g of the matting agent dispersion was added and stirred to prepare a surface protective layer coating solution.

<< Preparation of Photothermographic Material Sample 101 >>
The photosensitive layer coating solution A and the surface protective layer coating solution were simultaneously layer-coated using a known extrusion type coater. Coating was performed so that the photosensitive layer had a coated silver amount of 1.7 g / m ² and the surface protective layer had a dry film thickness of 2.5 μm. Thereafter, drying was performed for 10 minutes using a drying air having a drying temperature of 75 ° C. and a dew point temperature of 10 ° C., thereby obtaining a sample 101.

In addition solution a to be added to the photosensitive layer coating solution A, the amount of the compound of the compounds and of the general formula of the present invention (A-1) (A- 2), the respective ^{100mg / m 2, 30mg / m} 2 And added as shown in Table 2. The polymer P-9 was changed to the same amount of the polymer shown in Table 2. Further 25 mg / m ² to become so general formula (A-5) compound represented by (vinylsulfone group-containing compound), it is represented by way Formula Amount of ^{25mg / m 2 (A-3} ) The silver salt photothermal dry imaging material No. 1 was prepared in the same manner as in the photosensitive layer coating solution A except that the compounds were added to the photosensitive layer coating solution as shown in Table 2, respectively. 102 to 120 were produced.

《Exposure and development processing》
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 had been subjected to high frequency superimposition and had a wavelength of 800 to 820 nm and a multi-mode semiconductor laser as an exposure source. At this time, an image was formed by setting the angle between the exposure surface of the sample and the exposure laser beam to 75 ° (an image having less unevenness and unexpectedly good sharpness and the like as compared with the case where the angle was set to 90 °). Obtained).

Thereafter, using the above-described automatic developing machine having a heat drum and a cooling zone, the protective layer of the sample was brought into contact with the drum surface, and the developing temperature and the transport speed (linear speed) were also as shown in Table 2. The development was carried out with the change. At that time, exposure and development were performed in a room conditioned at 23 ° C. and 50% RH. The obtained image was evaluated using a densitometer. The measurement results are evaluated based on the sensitivity (reciprocal of the ratio of the exposure amount giving a density higher than that of the unexposed portion by 1.0), fog and the highest density. 2 is shown.

Table 2 also shows the thermal transition temperature after thermal development measured as follows.

評 価 Each evaluation item was measured by the following procedure.

<Measurement of thermal transition point temperature>
On a Teflon (R) plate, a photosensitive layer coating solution having the same composition as that described above was applied using a wire bar under the same conditions and dried, and then exposed and developed in the same manner under the condition that the highest density was obtained. Thereafter, the constituent layer applied from the Teflon (R) plate was peeled off. About 10 mg of the peeled sample was placed in an aluminum pan, and the thermal transition point temperature of each sample was measured using a differential scanning calorimeter (EXSTAR6000 manufactured by Seiko Instruments Inc.) in accordance with JIS K7121. The temperature was raised at a rate of 10 ° C./min from 0 to 200 ° C., cooled to 20 ° C./min at a rate of 20 ° C./min. I asked.

<Evaluation of image storability after development>
The minimum density and the maximum density change rate under certain conditions were measured as described below, and the image storability after development was evaluated.

(1) Measurement of minimum density (Dmin) change rate Each of the heat-developed samples prepared in the same manner as in the sensitivity measurement described above was placed under a 45 ° C./55% RH environment using a commercially available white fluorescent lamp on the sample surface. It was arranged so that the illuminance was 500 lux, and was irradiated continuously for three days. 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 were measured, and the minimum density change rate (%) was calculated by the following equation.

Minimum density variation ratio _{= D 2 / D 1 × 100} (%)
(2) Measurement of Maximum Density (Dmax) Change Rate Each heat-developed sample prepared by the same method as the above-described minimum density change rate measurement was left for 3 days in an environment of 25 ° C. and 45 ° C. The change in maximum density was measured, and the rate of change in image density was measured as described below, and this was used as a measure of image storability.

Image density change rate = (maximum density of sample stored at 45 ° C./maximum density of sample stored at 25 ° C.) × 100 (%)
<Evaluation of image tone of developed sample>
The wedge density portions of the fog, the highest density, and the sample subjected to the angular heat development which were measured for the relative sensitivity were measured with a CM-3600d (manufactured by Minolta Co., Ltd.) to determine u ^* , v ^* or a ^* , b ^* . Calculated. The measurement was performed in a transmission measurement mode with an F7 light source as a light source and a viewing angle of 10 °. The horizontal axis u ^* or a ^*, vertical axis v ^* or b ^* are plotted on the graph u ^*, v ^* or a ^*, b ^* were plotted obtains a linear regression line of determination R2, intercept and slope I asked.

<Evaluation of density unevenness>
Under the same exposure conditions as in the above-described exposure and development processing, exposure was performed so that the density became 1.5, and development processing was performed by changing the development temperature and speed. At that time, the cooling fan 152 was adjusted so that the surface temperature of the sample when it came out to the collecting section 160 by the developing machine shown in FIG.

(4) The prepared samples were visually evaluated for density unevenness in five steps based on the following criteria. If the level is B or higher, there is no major problem in actual products.

A: No unevenness is observed B: Slightly uneven unevenness is observed C: Weak unevenness is observed D: Slightly strong unevenness is observed E: Strong unevenness is observed The results are shown in Table 2.

As is clear from Table 2, the photothermographic material sample of the present invention has lower fog and higher preservability of the image after the development process than the comparative sample, while having the same sensitivity or higher. It was also found that the occurrence of density unevenness due to the development processing was small.

Example 2
A photothermographic dry imaging material was prepared in the same manner as in Example 1 except for the following.

<< Preparation of powdered aliphatic carboxylic acid silver salt B >>
<Preparation of powdered organic silver salt B containing silver halide particles>
Halogenation was carried out in exactly the same manner as in the case of the powdery silver halide-containing organic silver salt A, except that 150.0 g of behenic acid, 78.0 g of arachidic acid and 20.7 g of stearic acid were mixed and the dissolution temperature was 90 ° C. A powdery organic silver salt B containing silver particles was prepared. The amount of silver behenate in the powdered organic silver salt B containing silver halide particles was quantified by the above-mentioned analysis method, and the ratio of silver behenate contained in the organic silver salt particles B was 60% by mass.

<Preparation of powdered organic silver salt C containing silver halide particles>
A commercially available high-concentration behenic acid was used, and 217.0 g of behenic acid, 20.0 g of arachidic acid, and 17.3 g of stearic acid were used. Powdered organic silver salt C containing silver halide grains was prepared in exactly the same manner. The amount of silver behenate in the powdered organic silver salt C containing silver halide particles was quantified by the above-described analysis method, and the ratio of silver behenate contained in the organic silver salt particles C was 85% by mass. The heavy metal content was 3.5 ppm and the iodine value was 0.8.

<Preparation of powdered organic silver salt D containing silver halide particles>
The unpurified behenic acid reagent was recrystallized once with toluene, and as a result of analysis, 258.0 g of behenic acid whose content was increased to 92% by mass (of which 8% by mass contained arachidic acid) was used. , Behenic acid, 217.0 g of arachidic acid, 17.3 g of stearic acid, and a silver halide particle-containing powdered organic silver salt A except that the dissolution temperature was 90 ° C. In the same manner as described above, a powdered organic silver salt D containing silver halide particles was prepared. The amount of silver behenate in the powdered organic silver salt D containing silver halide particles was quantified by the above-mentioned analysis method, and the ratio of silver behenate contained in the organic silver salt particles D was 85% by mass. The heavy metal content was 2 ppm and the iodine value was 0.5.

<Preparation of powdered organic silver salt E containing silver halide particles>
The crude behenic acid reagent was recrystallized three times with toluene, and as a result of analysis, 259.3 g of behenic acid whose content was increased to 98% by mass (2% by mass contained arachidic acid) was used. Further, a powdered organic silver salt E containing silver halide particles was prepared in the same manner as in the case of the organic silver salt A containing silver halide particles except that the melting temperature was 90 ° C. The amount of silver behenate in the powdered organic silver salt E containing silver halide particles was quantified by the above-mentioned analysis method, and the ratio of silver behenate contained in the organic silver salt particles E was 98% by mass. The heavy metal content was 2 ppm or less, and the iodine value was 0.3.

<< Preparation of Preliminary Dispersions B to E >>
It was prepared in the same manner as in Example 1, except that the powdery non-photosensitive silver salts B to E were used.

<< Preparation of photosensitive emulsion dispersions B to E >>
The preparation was carried out in the same manner as in Example 1 except that the liquid dispersions were changed to the preliminary dispersions B to E.

<< Preparation of photosensitive layer coating solution B >>
A photosensitive layer coating liquid B was prepared using a photosensitive emulsion dispersion liquid B in the same manner as in the photosensitive layer coating liquid A of Example 1.

<< Preparation of silver salt photothermographic dry imaging material sample 201 >>
A silver salt photothermographic dry imaging material sample 101 in Example 1 was prepared using the photosensitive layer coating solution B and the surface protective layer coating solution in Example 1.

Samples 202 to 214 were prepared in the same manner as Sample 201 except that the photosensitive emulsion dispersion in the photosensitive layer coating solution and the compound of the present invention were changed to those shown in Table 3.

In each sample, the polymer P-1 was used as the binder resin in the photosensitive layer coating solution, and the thermal transition temperature of the photosensitive layer was adjusted to about 55 ° C.

Exposure, development, and various evaluations were performed in the same manner as in Example 1. Table 3 shows the results.

As is evident from Table 3, the photothermographic material sample of the present invention has high sensitivity as compared with the comparative sample, low fog, excellent storage stability before development and image storage after development, and It can be seen that the occurrence of density unevenness during development processing is small.

Example 3
The silver salt photothermography in Example 1 was repeated using the photosensitive layer coating solution A of Example 1 and the surface protective layer coating solution of Example 1 except that only the developer was replaced with the same amount of the developer shown in Table 4. 301 to 320 were produced in the same manner as the dry imaging material samples 101 to 120. In each sample, the polymer P-1 was used as a binder resin in the photosensitive layer coating solution, and the heat transition temperature of the photosensitive layer was adjusted to about 55 ° C. All evaluations were made at a developing speed of 125 ° C./20 mm / sec.

Comparative-2: 2,2'-methylenebis (4-ethyl-6-t-butylphenol)

FIG. 1 is a cross-sectional configuration diagram of a heat development processing apparatus according to the present invention.

Explanation of reference numerals

REFERENCE SIGNS LIST 1 heat drum 2 opposing roller 6 peeling claw 100 thermal developing device 110 feeding unit 120 exposing unit 130 developing unit 140, 144 supply roller pair 141, 142, 143 transport roller pair 150 cooling unit 151 cooling roller pair 152 cooling fan 160 accumulation unit F film

Claims (7)

Silver salt photothermographic dry imaging material having at least one photosensitive layer containing a photosensitive emulsion containing non-photosensitive organic silver salt particles and photosensitive silver halide particles, a silver ion reducing agent, and a binder on a support Wherein the silver salt photothermographic dry imaging material comprises at least one compound represented by the following general formula (A-1) and at least one compound represented by the following general formula (A-2).

(In the formula, X ₁ and X ₂ each represent a hydrogen atom, a halogen atom, an alkyl group, a cycloalkyl group, an alkenyl group, a cycloalkenyl group, an aryl group, a heterocyclic group, or a divalent linking group and a bond via this; And a group represented by —COO [1 / K (M)], wherein M represents a hydrogen atom or a K-valent cation, and X ₁ and X ₂ at least one is a group represented by -COO [1 / K (M)] .R ^1, R ^2, R ³ are each a hydrogen atom, a halogen atom, an alkyl group, a cycloalkyl group, an alkenyl group, a cycloalkenyl Group, an aryl group, a heterocyclic group, or a divalent linking group, and a group consisting of an aryl group and a heterocyclic group bonded via the divalent linking group. May be formed.)

(Wherein, Z represents a —S— group or —C (R ₃₃ ) (R ₃₃ ′) —, and R ₃₃ and R ₃₃ ′ represent a hydrogen atom or a substituent. R ₃₁ , R ₃₂ , and R ₃₁ 'And R ₃₂ ' represent a substituent, and X ₃₁ and X ₃₁ 'represent a hydrogen atom or a substituent.) 2. The silver salt photothermographic dry imaging material according to claim 1, wherein the heat-transition temperature of the photosensitive layer after development processing at a temperature of 100 to 200 ° C. is 46 to 200 ° C. The silver salt photothermographic dry imaging material according to claim 1 or 2, wherein the non-photosensitive organic silver salt particles contain 70 to 99% by mass of silver behenate. 4. The photosensitive layer according to claim 1, wherein at least one of the photosensitive layer and the layer provided adjacent to the photosensitive layer contains at least one compound containing a vinyl sulfone group. Item 13. The silver salt photothermographic dry imaging material according to item 1. The compound according to any one of claims 1 to 4, wherein at least one of the photosensitive layer and a layer provided adjacent to the photosensitive layer contains a compound represented by Formula (A-3). 4. The silver salt photothermographic dry imaging material according to claim 1.
General formula (A-3)
Z-SO ₂ -SM
(In the formula, Z represents a substituted or unsubstituted alkyl group, aryl group or heterocyclic group, and M represents a metal atom or an organic cation.) The silver salt photothermographic dry imaging material according to any one of claims 1 to 5, wherein the silver ion reducing agent is represented by a compound represented by the following general formula (A-4).

(Wherein, R ₁₁ and R ₁₂ each independently represent a hydrogen atom, a 3- to 10-membered non-aromatic cyclic group, or a 5- to 6-membered aromatic cyclic group, provided that R ₁₁ and R ₁₂ are simultaneously a hydrogen atom R ₁₃ and R ₁₄ each independently represent a hydrogen atom, an alkyl group, a cycloalkyl group, an alkenyl group, a cycloalkenyl group, an aryl group or a heterocyclic group, and Q represents a substituent on a benzene ring. Represents a group, and n represents an integer of 0 to 2. When Q is plural, each Q may be the same or different.) An image forming apparatus for subjecting the silver salt photothermographic dry imaging material according to any one of claims 1 to 6 to image exposure and heat development processing, wherein a portion between a supply part of the silver salt photothermographic dry imaging material and an image exposure part is provided. An image forming apparatus, wherein the conveying speed of the image forming apparatus is set to 20 to 200 mm / sec.

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