JP2004252439A - Heat developable photosensitive material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat developable photosensitive material with image color tone and image preservability simultaneously improved. <P>SOLUTION: In the heat developable photosensitive material containing a photosensitive silver halide, a non-photosensitive organic silver salt, reducing agents and a binder on the same surface of a support, at least one of the reducing agents is a compound represented by formula 1, wherein R<SP>1</SP>and R<SP>1'</SP>each independently represent a 1-20C alkyl; R<SP>2</SP>and R<SP>2'</SP>each independently represent a hydrogen atom or a substituent substitutable on a benzene ring; R<SP>3</SP>represents a substituent forming a 3- to 7-membered ring consisting of atoms selected from C, O, N, S, and P; and X and X' each independently represent a hydrogen atom or a group substitutable on a benzene ring. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photothermographic material having improved image tone and image storability, and more particularly to a photothermographic material having a small increase in fog and a small change in color tone when exposed to light such as Schaukasten for a long time. Is.

  In recent years, in the medical field, reduction of waste processing liquid has been strongly desired from the viewpoint of environmental protection and space saving. Therefore, photosensitive heat for medical diagnosis and photographic technology that can be efficiently exposed by a laser image setter or laser imager and can form a clear black image having high resolution and sharpness. There is a need for techniques relating to developed photographic materials. These photosensitive photothermographic materials can eliminate the use of solution processing chemicals and supply customers with a simpler heat development processing system that does not damage the environment.

  Although there is a similar requirement in the field of general image forming materials, medical images are required to have high image quality with excellent sharpness and graininess because they are required to be finely drawn, and are cooled from the viewpoint of ease of diagnosis. There is a feature that a black tone image is preferred. At present, various hard copy systems using pigments and dyes such as inkjet printers and electrophotography are distributed as general image forming systems. However, there is no satisfactory output system for medical images.

  On the other hand, thermal image forming systems using organic silver salts are known (see, for example, Patent Documents 1 and 2 and Non-Patent Document 1). In particular, the photothermographic material generally contains a catalytically active amount of a photocatalyst (eg, silver halide), a reducing agent, a reducible silver salt (eg, an organic silver salt), and a color tone that controls the color tone of silver if necessary. And a photosensitive layer dispersed in a binder matrix. The photothermographic material is heated to a high temperature (for example, 80 ° C. or higher) after image exposure, and is blackened by an oxidation-reduction reaction between silver halide or a reducible silver salt (functioning as an oxidizing agent) and a reducing agent. Form a silver image. The oxidation-reduction reaction is promoted by the catalytic action of the latent image of silver halide generated by exposure. Therefore, a black silver image is formed in the exposure area. Fuji Medical Dry Imager FM-DPL is disclosed as a medical image forming system using a photothermographic material disclosed in many documents including Patent Documents 3 and 4.

In manufacturing a thermal image forming system using an organic silver salt, there are a method of manufacturing by solvent coating and a method of manufacturing by coating and drying a coating liquid containing polymer fine particles as a water dispersion as a main binder. Since the latter method does not require a process such as solvent recovery, the production facility is simple and it is advantageous for mass production.
In any of the manufacturing methods, the biggest problem of the photothermographic material is that the fog is increased by the reactive compound remaining in the photosensitive material after development, or the image color tone is changed and the image is deteriorated. Was that. In order to solve this problem, diligent studies have been conducted, and improvements in thermal developers (see, for example, Patent Documents 5, 6, and 7) and image stabilizers (see, for example, Patent Document 8). Development has been done.

Particularly in medical image recording materials, the problem of image color tone is an extremely important quality because it affects the diagnostic ability, which is a major improvement problem required for photothermographic materials.
Many efforts have been made to control the silver tone of a photothermographic material image to a preferred color tone. For example, with respect to a silver carrier that greatly affects the silver color tone, development of a preferable silver carrier (see, for example, Patent Document 9), development of a color tone adjusting agent as a method for controlling the color tone (for example, see Patent Document 10), and other methods. Development of color tone adjustment technology (see, for example, Patent Documents 11 to 14) was performed.

However, even with the above-described technology, there has been a situation in which a satisfactory image has not been obtained from the viewpoint of achieving both image color tone and image storage stability.
U.S. Pat. No. 3,152,904 U.S. Pat. No. 3,457,075 US Patent 2910377 Japanese Patent Publication No.43-4924 JP 2001-188314 A JP 2002-365758 A JP 2001-209145 A JP 2001-281793 A JP-A-9-149249, etc. JP 2002-169249 A JP 2000-241927 A JP 2001-330923 A JP 2001-330925 A JP 2002-49123 A D. H. “Thermally Processed Silver Systems” by Kolsterboer (Imaging Processes and Materials), 8th edition, Sturge (Australia) (Walworth, A. Shepp, Chapter 9, 279, 1989)

  Accordingly, an object of the present invention is to provide a photothermographic material which forms an image having a preferable color tone and at the same time has a small increase in fog and change in image color tone with respect to long-term storage in a dark place.

The object of the present invention has been achieved by the following photothermographic materials.
<1> A photothermographic material containing a photosensitive silver halide, a non-photosensitive organic silver salt, a reducing agent and a binder on the same surface of a support, wherein at least one of the reducing agents is represented by the following general formula ( A photothermographic material characterized by being a compound represented by R1):

Formula (R1)

(In the formula, R ¹ and R ¹ ′ each independently represent an alkyl group having 1 to 20 carbon atoms. R ² and R ² ′ each independently represent a hydrogen atom or a substituent that can be substituted on a benzene ring. R ³ represents a substituent which forms a ring composed of atoms selected from 3 to 7-membered carbon atoms, oxygen atoms, nitrogen atoms, sulfur atoms and phosphorus atoms, X and X ′ are each independently a hydrogen atom or benzene Represents a substitutable group on the ring).
<2> The photothermographic material according to <1>, further comprising a color former capable of developing color by heat development.
<3> The photothermographic material according to <2>, wherein the color former is a compound capable of forming a dye having main absorption in a wavelength region of 350 nm to 500 nm or 600 nm to 700 nm.
<4> The photothermographic material according to <2> or <3>, wherein the color former is a compound that forms a yellow dye having main absorption in a wavelength region of 350 nm to 500 nm.
<5> The photothermographic material according to any one of <2> to <4>, wherein the color former is a compound represented by the following general formula C:

General formula (C)

(General formula (C) in R ₁ and R ₂ are each independently a halogen atom, an alkyl group, an alkoxy group, an amino group, an acylamino group, an acyloxy group, an acyl group, an alkoxycarbonyl group or a carbamoyl group, R ₃ and R ₄ each independently represents a hydrogen atom, a halogen atom, a hydroxyl group, an amino group, an alkoxy group, an acyloxy group, an acylamino group, an aryl group or a heterocyclic group.
<6> In the reducing agent represented by the general formula (R1), wherein at least one of R ¹ or R ^{1 'is} secondary or tertiary alkyl groups <1> to the <5> The photothermographic material according to any one of the above.
<7> The photothermographic material according to any one of <1> to <6>, wherein a hue angle at an image density of 1.0 is in a range of 180 ° to 270 °.
<8>Gin'nuri設量is lies in the range of ^{0.8g / m 2 ~1.9g / m 2} <1> ~ photothermographic material according to any one of <7>.
<9> The photothermographic material according to any one of <1> to <8>, wherein the heat development time is in the range of 6 seconds to 14 seconds.
<10> The photothermographic material according to any one of <1> to <9>, wherein the ratio of developed silver in the highest image density portion is 85% or more based on the total amount of applied silver.

  The present invention provides a photothermographic material having improved image color tone and image storage stability at the same time.

The present invention is described in detail below.
(Description of reducing agent)
The reducing agent of the present invention is a compound represented by the following general formula (R1), which is a compound capable of reducing silver ions to develop silver during thermal development.

The general formula (R1) will be described in detail.
1) R ¹ and R ¹ '
R ¹ and R ¹ ′ are each independently a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, and the substituent of the alkyl group is not particularly limited, but is preferably an aryl group, a hydroxy group , Alkoxy groups, aryloxy groups, alkylthio groups, arylthio groups, acylamino groups, sulfonamido groups, sulfonyl groups, phosphoryl groups, acyl groups, carbamoyl groups, ester groups, ureido groups, urethane groups, halogen atoms and the like.

R ¹ and R ¹ ′ are preferably a secondary or tertiary alkyl group having 3 to 15 carbon atoms, and specifically, an isopropyl group, an isobutyl group, a t-butyl group, a t-amyl group, and a t-octyl group. Cyclohexyl group, cyclopentyl group, 1-methylcyclohexyl group, 1-methylcyclopropyl group and the like. R ¹¹ and R ¹¹ ′ are more preferably a tertiary alkyl group having 4 to 12 carbon atoms, and among them, a t-butyl group, a t-amyl group, and a 1-methylcyclohexyl group are more preferable, and a t-butyl group is most preferable. .

2) R ² and R ² ', X and X'
R ² and R ² ′ each independently represent a hydrogen atom or a substituent that can be substituted on the benzene ring, and X and X ′ each independently represent a hydrogen atom or a group that can be substituted on the benzene ring.
Preferred examples of each group that can be substituted on the benzene ring include an alkyl group, an aryl group, a halogen atom, an alkoxy group, and an acylamino group.

R ² and R ² ′ are preferably an alkyl group having 1 to 20 carbon atoms, specifically, a methyl group, an ethyl group, a propyl group, a butyl group, an isopropyl group, a t-butyl group, a t-amyl group, a cyclohexyl group. Group, 1-methylcyclohexyl group, benzyl group, methoxymethyl group, methoxyethyl group and the like. More preferred are methyl group, ethyl group, propyl group, isopropyl group and t-butyl group.
X and X ′ are preferably a hydrogen atom, a halogen atom or an alkyl group, more preferably a hydrogen atom.

3) R ³
R ³ represents a substituent that forms a ring composed of a 3- to 7-membered carbon atom, oxygen atom, nitrogen atom, sulfur atom, or phosphorus atom. All the rings may be carbon atoms, or may be heterocyclic groups composed of carbon atoms and the above heteroatoms.
R ³ is preferably a group having 3 to 20 carbon atoms forming a 5- to 6-membered carbocyclic or heterocyclic ring, more preferably a group forming a ring consisting of a carbon atom or an oxygen atom.

  These rings may contain an unsaturated bond.

These rings may have a substituent. The range of the carbon number including the substituent is preferably from 2 to 30.
Examples of the substituent represented by R ³ include halogen atoms, alkyl groups, alkenyl groups, alkynyl groups, cycloalkyl groups, aryl groups, alkoxy groups, alkylthio groups, aryloxy groups, arylthio groups, allyloxy groups, Examples include allylthio group, acylamino group, sulfonamido group, sulfonyl group, phosphoryl group, carbonyl group, oxycarbonyl group, carbamoyl group, sulfamoyl group, heterocyclic group, amino group, hydroxy group and the like.

Specific examples of the cyclic group represented by R ³ are cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, 2-norbornyl group, 2- [2,2,2] -bicyclooctyl group, 2 -Adamantyl group, 2-cyclopentenyl group, 2-cyclohexenyl group, 3-cyclohexenyl group, 2-tetrahydrofuranyl group, 2-dihydrofuranyl group, 2-tetrahydropyranyl group, 3-dihydropyranyl group, 2 -Pyrrolidine group, 2-piperidine group, 3-tetrahydrothiopyranyl group, 3-tetrahydrophosphorane group and the like.

More preferred specific examples of the cyclic group represented by R ³ are a cycloalkyl group having 1 to 15 carbon atoms, a cycloalkenyl group, and a heterocyclic group, and the cycloalkyl group is preferably a cyclohexyl group or a cyclopentyl group, The group is preferably a 2-cyclohexenyl group, a 3-cyclohexenyl group, or a 3-cyclopentenyl group. As the heterocyclic group, a 2-tetrahydrofuranyl group, a 2-tetrahydropyranyl group, and a 3-tetrahydropyranyl group are preferable. R ³ is particularly preferably a cyclohexyl group, a 3-cyclohexenyl group or a 3-cyclopentenyl group.

  Although the above reducing agents can be used alone, it is preferable to use two or more kinds in combination for the purpose of adjusting developability and color tone. Moreover, it can be used in combination with a reducing agent other than the present invention. A preferable reducing agent that can be used in combination with the reducing agent of the present invention is a reducing agent represented by the following general formula (R).

  Specific examples of the compound represented by the general formula (R1) of the present invention are shown below, but the present invention is not limited thereto.

The addition amount of the reducing agent is preferably a ^{0.1g / m 2 ~3.0g / m 2} , more preferably ^{0.2g / m 2 ~1.5g / m 2} , more preferably 0 .3 g / m ^{2 to} 1.0 g / m ² . It is preferably contained in an amount of 5 mol% to 50% mol, more preferably 8 mol% to 30 mol%, and more preferably 10 mol% to 20 mol%, based on 1 mol of silver on the surface having the image forming layer. More preferably. The reducing agent is preferably contained in the image forming layer.

The reducing agent may be contained in the coating solution by any method such as a solution form, an emulsified dispersion form, or a solid fine particle dispersion form, and may be contained in the photosensitive material.
Well-known emulsification dispersion methods include dissolving oil using an oil such as dibutyl phthalate, tricresyl phosphate, glyceryl triacetate or diethyl phthalate, or an auxiliary solvent such as ethyl acetate or cyclohexanone, and mechanically emulsifying the dispersion. The method of producing is mentioned.

In addition, as a solid fine particle dispersion method, a reducing agent powder is dispersed in an appropriate solvent such as water by a ball mill, a colloid mill, a vibration ball mill, a sand mill, a jet mill, a roller mill, or an ultrasonic wave to create a solid dispersion. A method is mentioned. In this case, a protective colloid (for example, polyvinyl alcohol) or a surfactant (for example, an anionic surfactant such as sodium triisopropylnaphthalenesulfonate (a mixture of three isopropyl groups having different substitution positions)) may be used. Good. In the mills, beads such as zirconia are usually used as a dispersion medium, and Zr and the like eluted from these beads may be mixed in the dispersion. Although it depends on the dispersion conditions, it is usually in the range of 1 ppm to 1000 ppm. If the Zr content in the light-sensitive material is 0.5 mg or less per 1 g of silver, there is no practical problem.
The aqueous dispersion preferably contains a preservative (for example, benzoisothiazolinone sodium salt).
Particularly preferred is a solid particle dispersion method of a reducing agent, and it is preferable to add fine particles having an average particle size of 0.01 μm to 10 μm, preferably 0.05 μm to 5 μm, more preferably 0.1 μm to 2 μm. In the present application, it is preferable to use other solid dispersions dispersed in a particle size within this range.

(Description of color former that can develop color by heat development)
The color former that can develop color by heat development of the present invention means that when heat development is performed, a dye is not substantially formed in the non-exposed non-image area, and a dye is formed in the image area where developed silver is formed. Refers to the compound. This compound may be a compound that develops color alone, or may form a dye by a coupling reaction, elimination reaction, or other reaction of two or more compounds.
Silver images produced by heat development often have more magenta components than neutral colors, and the dyes formed by the color former of the present invention preferably have absorption in the yellow or cyan region. In terms of the wavelength region of the generated dye, a compound having 70% or more of absorption in a yellow region of 350 nm to 500 nm or a cyan region of 600 nm to 700 nm is preferable. In particular, a compound having 70% or more in the 350 nm to 500 nm region is preferable, and a compound having 70% or more absorption in the 380 nm to 460 nm region is more preferable.

Examples of color formers that form dyes alone include phenols having a methylene group substituted with a methyl group or a hetero atom at the para position, and para-bisphenols having a specific substituent at the ortho position. . Examples of color formers that form dyes by coupling reactions of two or more compounds include paraphenylenediamines or carbamoylhydrazines and compounds well known as color couplers, such as 2-acylaminophenols and naphthols. Pyrrolotriazoles, pyrazolotriazoles, 5-pyrazolones, and acylacetanilides. Preferable examples of these color formers are compounds described in JP-A Nos. 2001-330923, 330925 and 2002-49123.
Particularly preferred color formers in the present invention are compounds represented by the following general formula (C).

General formula (C)

In general formula (C), R ₁ and R ₂ are each independently a halogen atom, alkyl group, alkoxy group, amino group, acylamino group, acyloxy group, acyl group, alkoxycarbonyl group, sulfide group, sulfonyl group, disulfide group, Represents a sulfamoyl group or a carbamoyl group, and R ₃ and R ₄ each independently represents a hydrogen atom, a halogen atom, a hydroxyl group, an amino group, an alkoxy group, an aryloxy group, an acyloxy group, an acylamino group, a sulfide group, a disulfide group, an aryl group Or represents a heterocyclic group.

R ₁ and R ₂ will be described in detail.
When R ₁ and R ₂ represent a halogen atom, it is preferably a chlorine atom or a bromine atom, more preferably a chlorine atom.
When R ₁ and R ₂ are alkyl groups, they are alkyl groups having 1 to 24 carbon atoms, preferably 3 to 12 carbon atoms, and may have a substituent. Moreover, it may be linear or branched and may form a ring. For example, methyl group, ethyl group, n-butyl group, n-dodecyl group, isopropyl group, t-butyl group, t-amyl group, cyclohexyl group, 1-methylcyclohexyl group, benzyl group, 2-hydroxybenzyl group, 3 -T-butyl-5-methyl-2-hydroxybenzyl group, chloromethyl group, hydroxymethyl group and the like can be mentioned. A secondary or tertiary alkyl group or a cycloalkyl group is preferred, and a tertiary alkyl group is more preferred. A benzyl group is also a preferred substituent.

When R ₁ and R ₂ represent an alkoxy group, the alkoxy group preferably has 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, and may have a substituent. Examples thereof include a methoxy group, an ethoxy group, an isopropoxy group, a t-butoxy group, an octyloxy group, a cyclohexyloxy group, a benzyloxy group, and a methoxyethoxy group.

When R ₁ and R ₂ represents an amino group, preferably having 1 to 20 carbon atoms, more preferably 2 to 12 amino groups, which may have a substituent. For example, an amino group, N-methylamino group, N, N-dimethylamino group, N-butylamino group, anilino group, N-methylanilino group, cyclohexylamino group, piperidinyl group, morpholino group and the like can be mentioned.

When R ₁ and R ₂ represent an acylamino group, it is preferably an acylamino group having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, which may have a substituent. Examples include acetylamino group, methylureido group, ethylurethane group, benzoylamino group, propionylamino group, pivaloylamino group and the like.
When R ₁ and R ₂ represent an acyloxy group, it is preferably an acyloxy group having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, which may have a substituent. Examples thereof include an acetoxy group and a benzoyloxy group.

When R ₁ and R ₂ represent an acyl group, the acyl group preferably has 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, and may have a substituent. For example, acetyl group, myristoyl group, benzoyl group and the like can be mentioned.
When R ₁ and R ₂ represent an alkoxycarbonyl group, it is preferably an alkoxycarbonyl group having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, which may have a substituent. Examples thereof include a methoxycarbonyl group, a cyclohexyloxycarbonyl group, an octyloxycarbonyl group, and the like.

When R ₁ and R ₂ represent a carbamoyl group, it is preferably a carbamoyl group having 1 to 20 carbon atoms, more preferably 2 to 12 carbon atoms, which may have a substituent. Examples thereof include an N, N-dimethylcarbamoyl group and an N, N-diethylcarbamoyl group.
R ₁ and R ₂ are preferably alkyl groups, and at least one of them is preferably a secondary or tertiary alkyl group or a benzyl group. Most preferably, R ₁ and R ₂ are either a tertiary alkyl group or a benzyl group.

Next, R ₃ and R ₄ will be described in detail.
When R ₃ and R ₄ are a halogen atom, an alkoxy group, an amino group, an alkoxy group, an acyloxy group, or an acylamino group, the same as in the case of R ₁ and R ₂ .
When R ₃ and R ₄ are aryloxy groups, they are preferably aryloxy groups having 6 to 25 carbon atoms, such as phenoxy group, naphthoxy group, cresyloxy group, xylyloxy group, 4-methoxyphenoxy group, 2,4-dichlorophenoxy group. Group and the like.

When R ₃ and R ₄ are aryl groups, they are preferably aryl groups having 6 to 25 carbon atoms, such as phenyl, naphthyl, cresyl, xylyl, 4-methoxyphenyl, 2,4-dichlorophenyl, 3 , 5-dimethyl-4-hydroxyphenyl group, 3-methyl-5-tert-butyl-4-hydroxyphenyl group, 3,5-di-tert-butyl-4-hydroxyphenyl group, and the like.
When R ₃ and R ₄ are heterocyclic groups, they are preferably heterocyclic groups having 3 to 25 carbon atoms such as pyridinyl group and quinolyl group.

R ₃ and R ₄ are preferably a hydrogen atom, an aryl group, an alkoxy group, a hydroxy group or an amino group, more preferably a hydrogen atom or an aryl group. Either R ₃ or R ₄ is preferably a hydrogen atom.
Specific examples of preferred compounds of the present invention are given below, but the present invention is not limited to these compounds.

  The compound represented by formula (C) can be added to the light-sensitive material in the same manner as the developer of the present invention. The preferred amount used is in the range of 0.1 mol% to 50 mol%, more preferably in the range of 1 mol% to 10 mol% with respect to the developer.

(Description of organic silver salt)
1) Composition The organic silver salt that can be used in the present invention is relatively stable to light, but is heated to 80 ° C. or higher in the presence of exposed photosensitive silver halide and a reducing agent. In this case, the silver salt functions as a silver ion supplier to form a silver image. The organic silver salt may be any organic substance that can supply silver ions that can be reduced by a reducing agent. As for such non-photosensitive organic silver salt, paragraph numbers 0048 to 0049 of JP-A-10-62899, page 18 line 24 to page 19 line 37 of European Patent Publication No. 0803764A1, European Patent Publication. No. 0968212A1, JP-A-11-349591, JP-A-2000-7683, JP-A-2000-72711, and the like. Silver salts of organic acids, particularly silver salts of long-chain aliphatic carboxylic acids (having 10 to 30, preferably 15 to 28 carbon atoms) are preferred. Preferred examples of the fatty acid silver salt include silver lignocerate, silver behenate, silver arachidate, silver stearate, silver oleate, silver laurate, silver caproate, silver myristate, silver palmitate, silver erucate and the like. Including a mixture of In the present invention, among these fatty acid silvers, the silver behenate content is preferably 50 mol% to 100 mol%, more preferably 85 mol% to 100 mol%, still more preferably 95 mol% to 100 mol%. The following fatty acid silver is preferably used. Furthermore, it is preferable to use fatty acid silver having a silver erucate content of 2 mol% or less, more preferably 1 mol% or less, and still more preferably 0.1 mol% or less.

  Moreover, it is preferable that silver stearate content rate is 1 mol% or less. By setting the silver stearate content to 1 mol% or less, a silver salt of an organic acid having a low Dmin, high sensitivity and excellent image storage stability can be obtained. As said silver stearate content rate, 0.5 mol% or less is preferable and it is especially preferable not to contain substantially.

  Furthermore, when silver arachidate is included as the silver salt of the organic acid, the silver arachidate content is 6 mol% or less to obtain a low Dmin and an organic acid silver salt excellent in image storability. It is preferable at a point and it is still more preferable that it is 3 mol% or less.

2) Shape The shape of the organic silver salt that can be used in the present invention is not particularly limited, and may be any of a needle shape, a rod shape, a flat plate shape, and a flake shape.
In the present invention, scaly organic silver salts are preferred. In addition, short needle-shaped, rectangular parallelepiped, cubic or potato-shaped irregular particles having a major axis / uniaxial length ratio of less than 5 are also preferably used. These organic silver particles have a feature that there is less fog at the time of thermal development than long needle-like particles having a ratio of the major axis to the uniaxial length of 5 or more. In particular, particles having a major axis / uniaxial ratio of 3 or less are preferable because the mechanical stability of the coating film is improved. In the present specification, the scaly organic silver salt is defined as follows. The organic acid silver salt was observed with an electron microscope, the shape of the organic acid silver salt particle was approximated to a rectangular parallelepiped, and the sides of the rectangular parallelepiped were designated as a, b, and c from the shortest side (c was the same as b). Then, the shorter numerical values a and b are calculated, and x is obtained as follows.
x = b / a

  In this way, x is obtained for about 200 particles, and when the average value x (average) is obtained, particles satisfying the relationship of x (average) ≧ 1.5 are defined as flakes. Preferably, 30 ≧ x (average) ≧ 1.5, more preferably 15 ≧ x (average) ≧ 1.5. Incidentally, the needle shape is 1 ≦ x (average) <1.5.

  In the flake shaped particle, a can be regarded as a thickness of a tabular particle having a main plane with b and c as sides. The average of a is preferably 0.01 μm or more and 0.3 μm or less, and more preferably 0.1 μm or more and 0.23 μm or less. The average c / b is preferably 1 or more and 9 or less, more preferably 1 or more and 6 or less, still more preferably 1 or more and 4 or less, and most preferably 1 or more and 3 or less.

By setting the equivalent sphere diameter to 0.05 μm or more and 1 μm or less, aggregation is hardly caused in the photosensitive material, and image storability is improved. The sphere equivalent diameter is preferably 0.1 μm or more and 1 μm or less.
In the present invention, the method for measuring the equivalent sphere diameter is obtained by directly photographing a sample using an electron microscope and then image-processing the negative.
In the flake shaped particles, the spherical equivalent diameter / a of the particles is defined as the aspect ratio. The aspect ratio of the flake shaped particles is preferably 1.1 or more and 30 or less, more preferably 1.1 or more and 15 or less, from the viewpoint of preventing aggregation in the photosensitive material and improving the image storage stability. .

  The particle size distribution of the organic silver salt is preferably monodispersed. Monodispersion is preferably 100% or less, more preferably 80% or less, and even more preferably 50% of the value obtained by dividing the standard deviation of the lengths of the short and long axes by the short and long axes. It is as follows. The method for measuring the shape of the organic silver salt can be determined from a transmission electron microscope image of the organic silver salt dispersion. As another method for measuring monodispersity, there is a method for obtaining the standard deviation of the volume weighted average diameter of the organic silver salt, and the percentage (variation coefficient) of the value divided by the volume weighted average diameter is preferably 100% or less, more Preferably it is 80% or less, More preferably, it is 50% or less. As a measuring method, for example, it is obtained from the particle size (volume weighted average diameter) obtained by irradiating an organic silver salt dispersed in a liquid with laser light and obtaining an autocorrelation function with respect to the temporal change of the fluctuation of the scattered light. Can do.

3) Preparation Known methods and the like can be applied to the production and dispersion method of organic acid silver used in the present invention. For example, the above-mentioned JP-A-10-62899, European Patent Publication No. 0803763A1, European Patent Publication No. 0968212A1, JP-A-11-349591, JP-A-2000-7683, JP-A-2000-72711, JP-A-2001-163889, 2001-163890, 2001-163825, 2001-33907, 2001-188313, 2001-83651, 2002-6442, 2002-49117, 2002-31870, 2002-107868 You can refer to the issue.

  In addition, when the photosensitive silver salt is allowed to coexist at the time of dispersion of the organic silver salt, the fog is increased and the sensitivity is remarkably reduced. Therefore, it is more preferable that the photosensitive silver salt is not substantially contained at the time of dispersion. In the present invention, the amount of the photosensitive silver salt in the aqueous dispersion to be dispersed is preferably 1 mol% or less, more preferably 0.1 mol% relative to 1 mol of the organic acid silver salt in the liquid. The following is more preferable, and positive addition of photosensitive silver salt is not performed.

  In the present invention, it is possible to produce a photosensitive material by mixing an organic silver salt aqueous dispersion and a photosensitive silver salt aqueous dispersion, but the mixing ratio of the organic silver salt and the photosensitive silver salt can be selected according to the purpose, The ratio of the photosensitive silver salt to the organic silver salt is preferably in the range of 1 mol% to 30 mol%, more preferably in the range of 2 mol% to 20 mol%, particularly 3 mol% to 15 mol%. Mixing two or more organic silver salt water dispersions and two or more photosensitive silver salt water dispersions when mixing is a method preferably used for adjusting photographic properties.

4) Addition Amount organic silver salt in the invention can be used in a desired amount, preferably 0.1g / m ² ~5.0g / m ² as the total amount of coated silver halide silver was also included, and more preferably 0 ^{.5g / m 2 ~3.0g / m 2} , more preferably from ^{0.8g / m 2 ~1.9g / m 2} . In particular, in order to improve image storability, the total coated silver amount is preferably 1.7 g / m ² or less, more preferably 1.5 g / m ² or less. If the preferred reducing agent of the present invention is used, it is possible to obtain a sufficient image density even with such a low silver amount.

(Description of reducing agent that can be used in combination with the reducing agent of the present invention)
In the photothermographic material of the invention, as the reducing agent for the organic silver salt, another reducing agent can be used in combination with the compound of the general formula (R1). The reducing agent that can be used in combination may be any substance (preferably an organic substance) that reduces silver ions to metallic silver. Examples of such reducing agents are described in JP-A No. 11-65021, paragraphs 0043 to 0045, and European Patent Publication No. 0803764A1, page 7, line 34 to page 18, line 12.
The reducing agent that can be used in the present invention is preferably a so-called hindered phenol-based reducing agent or bisphenol-based reducing agent having a substituent at the ortho position of the phenolic hydroxyl group, and is a compound represented by the following general formula (R): The combined use is more preferable.

General formula (R)

(In the general formula (R), R ¹¹ and R ¹¹ ′ each independently represents an alkyl group having 1 to 20 carbon atoms. R ¹² and R ¹² ′ are each independently a substituent which can be substituted on a hydrogen atom or a benzene ring. the representative .L -S- group or a -CHR ¹³ - group .R ¹³ is a hydrogen atom or a benzene ring .X ¹ and X ¹ 'each independently represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms Represents a substitutable group.

The general formula (R) will be described in detail.
1) R ¹¹ and R ¹¹ '
R ¹¹ and R ¹¹ ′ are each independently a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, and the substituent of the alkyl group is not particularly limited, but is preferably an aryl group, a hydroxy group, Examples thereof include an alkoxy group, an aryloxy group, an alkylthio group, an arylthio group, an acylamino group, a sulfonamide group, a sulfonyl group, a phosphoryl group, an acyl group, a carbamoyl group, an ester group, a ureido group, a urethane group, and a halogen atom.

2) R ¹² and R ¹² ', X ¹ and X ¹ '
R ¹² and R ¹² ′ each independently represent a hydrogen atom or a substituent capable of substituting for a benzene ring, and X ¹ and X ¹ ′ each independently represent a hydrogen atom or a group capable of substituting for a benzene ring. Preferred examples of each group that can be substituted on the benzene ring include an alkyl group, an aryl group, a halogen atom, an alkoxy group, and an acylamino group.

3) L
L represents an —S— group or a —CHR ¹³ — group. R ¹³ represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, and the alkyl group may have a substituent. Specific examples of the unsubstituted alkyl group represented by R ¹³ include a methyl group, an ethyl group, a propyl group, a butyl group, a heptyl group, an undecyl group, an isopropyl group, a 1-ethylpentyl group, and a 2,4,4-trimethylpentyl group. can give. Examples of the substituent of the alkyl group are the same as the substituent of R ¹¹ , and are a halogen atom, alkoxy group, alkylthio group, aryloxy group, arylthio group, acylamino group, sulfonamido group, sulfonyl group, phosphoryl group, oxycarbonyl group, Examples thereof include a carbamoyl group and a sulfamoyl group.

4) Preferred substituents R ¹¹ and R ¹¹ ′ are preferably secondary or tertiary alkyl groups having 3 to 15 carbon atoms, specifically isopropyl, isobutyl, t-butyl, t-amyl groups. , T-octyl group, cyclohexyl group, cyclopentyl group, 1-methylcyclohexyl group, 1-methylcyclopropyl group and the like. R ¹¹ and R ¹¹ ′ are more preferably a tertiary alkyl group having 4 to 12 carbon atoms, and among them, a t-butyl group, a t-amyl group, and a 1-methylcyclohexyl group are more preferable, and a t-butyl group is most preferable. .

R ¹² and R ¹² ′ are preferably an alkyl group having 1 to 20 carbon atoms, specifically, a methyl group, an ethyl group, a propyl group, a butyl group, an isopropyl group, a t-butyl group, a t-amyl group, a cyclohexyl group. Group, 1-methylcyclohexyl group, benzyl group, methoxymethyl group, methoxyethyl group and the like. More preferred are methyl group, ethyl group, propyl group, isopropyl group and t-butyl group.
X ¹ and X ¹ ′ are preferably a hydrogen atom, a halogen atom, or an alkyl group, and more preferably a hydrogen atom.

L is preferably a —CHR ¹³ — group.
R ¹³ is preferably a hydrogen atom or an alkyl group having 1 to 15 carbon atoms, and the alkyl group is preferably a methyl group, an ethyl group, a propyl group, an isopropyl group, or a 2,4,4-trimethylpentyl group. R ¹³ is particularly preferably a hydrogen atom, a methyl group, an ethyl group, a propyl group or an isopropyl group.

When R ¹³ is a hydrogen atom, R ¹² and R ¹² ′ are preferably an alkyl group having 2 to 5 carbon atoms, more preferably an ethyl group or a propyl group, and most preferably an ethyl group.
When R ¹³ is a primary or secondary alkyl group having 1 to 8 carbon atoms, R ¹² and R ¹² ′ are preferably methyl groups. As the primary or secondary alkyl group having 1 to 8 carbon atoms for R ^13, a methyl group, an ethyl group, a propyl group, or an isopropyl group is more preferable, and a methyl group, an ethyl group, or a propyl group is still more preferable.
When all of R ¹¹ , R ¹¹ ′, R ¹² and R ¹² ′ are methyl groups, R ¹³ is preferably a secondary alkyl group. In this case, the secondary alkyl group of R ¹³ is preferably an isopropyl group, an isobutyl group, or a 1-ethylpentyl group, and more preferably an isopropyl group.
The reducing agent has different heat developability, developed silver color tone, and the like depending on the combination of R ¹¹ , R ¹¹ ′, R ¹² , R ¹² ′ and R ¹³ . Since these can be adjusted by combining two or more kinds of reducing agents, it is preferable to use two or more kinds in combination depending on the purpose.

  Although the specific example of the reducing agent of this invention including the compound represented by general formula (R) of this invention below is shown, this invention is not limited to these.

  Examples of preferable reducing agents of the present invention other than the above are compounds described in JP-A Nos. 2001-188314, 2001-209145, 2001-350235, and 2002-156727.

  The compound of the general formula (R) can be dispersed by the same method as the reducing agent of the present invention and added to the light-sensitive material.

The use ratio (R / R1 mass ratio) of the compound represented by the above general formula (R) and the compound represented by the general formula (R1) of the present invention is 90/10 to 0/100, preferably 70 / It is 30-0 / 100, More preferably, it is 50 / 50-0 / 100.
The total amount of these reducing agents used is preferably in the range of the amount described for the reducing agent of the present invention.

(Description of development accelerator)
In the photothermographic material of the present invention, a sulfonamide phenol compound represented by the general formula (A) described in JP-A-2000-267222, JP-A-2000-330234, or the like as a development accelerator, Hindered phenol compounds represented by general formula (II) described in JP-A-2001-92075, general formula (I) described in JP-A-10-62895, JP-A-11-15116, and the like, A hydrazine-based compound represented by general formula (D) of JP-A No. 2002-156727 or general formula (1) described in JP-A No. 2002-278017, and described in JP-A No. 2001-264929 A phenolic or naphtholic compound represented by the general formula (2) is preferably used. These development accelerators are used in the range of 0.1 mol% to 20 mol% with respect to the reducing agent, preferably in the range of 0.5 to 10 mol%, more preferably 1 mol% to 5 mol%. It is a range. The introduction method to the light-sensitive material includes the same method as the reducing agent, but it is particularly preferable to add as a solid dispersion or an emulsion dispersion. When added as an emulsified dispersion, it is added as an emulsified dispersion dispersed using a high-boiling solvent and a low-boiling auxiliary solvent that are solid at room temperature, or as a so-called oilless emulsified dispersion that does not use a high-boiling solvent. It is preferable to add.
In the present invention, among the development accelerators described above, hydrazine compounds represented by the general formula (D) described in JP-A No. 2002-156727 and those described in JP-A No. 2001-264929 A phenol-based or naphthol-based compound represented by the formula (2) is more preferable.

Particularly preferred development accelerators of the present invention are compounds represented by the following general formulas (A-1) and (A-2).
Formula (A-1)
Q ₁ -NHNH-Q ₂
(Wherein Q ₁ represents an aromatic group or a heterocyclic group bonded to —NHNH—Q ₂ at a carbon atom, and Q ₂ represents a carbamoyl group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a sulfonyl group, Or represents a sulfamoyl group.)

In the general formula (A-1), the aromatic group or heterocyclic group represented by Q ₁ is preferably a 5- to 7-membered unsaturated ring. Preferred examples include benzene ring, pyridine ring, pyrazine ring, pyrimidine ring, pyridazine ring, 1,2,4-triazine ring, 1,3,5-triazine ring, pyrrole ring, imidazole ring, pyrazole ring, 1,2 , 3-triazole ring, 1,2,4-triazole ring, tetrazole ring, 1,3,4-thiadiazole ring, 1,2,4-thiadiazole ring, 1,2,5-thiadiazole ring, 1,3,4 -Oxadiazole ring, 1,2,4-oxadiazole ring, 1,2,5-oxadiazole ring, thiazole ring, oxazole ring, isothiazole ring, isoxazole ring, thiophene ring, etc. are preferable, and these Also preferred are fused rings in which the rings are fused together.

  These rings may have a substituent, and when they have two or more substituents, these substituents may be the same or different. Examples of substituents include halogen atoms, alkyl groups, aryl groups, carbonamido groups, alkylsulfonamido groups, arylsulfonamido groups, alkoxy groups, aryloxy groups, alkylthio groups, arylthio groups, carbamoyl groups, sulfamoyl groups, cyano Groups, alkylsulfonyl groups, arylsulfonyl groups, alkoxycarbonyl groups, aryloxycarbonyl groups, and acyl groups. When these substituents are substitutable groups, they may further have substituents. Examples of preferred substituents include halogen atoms, alkyl groups, aryl groups, carbonamido groups, alkylsulfonamido groups, aryls. A sulfonamide group, alkoxy group, aryloxy group, alkylthio group, arylthio group, acyl group, alkoxycarbonyl group, aryloxycarbonyl group, carbamoyl group, cyano group, sulfamoyl group, alkylsulfonyl group, arylsulfonyl group, and acyloxy group; Can be mentioned.

The carbamoyl group represented by Q ₂ is preferably a carbamoyl group having 1 to 50 carbon atoms, more preferably 6 to 40 carbon atoms. For example, unsubstituted carbamoyl, methylcarbamoyl, N-ethylcarbamoyl, N-propylcarbamoyl N-sec-butylcarbamoyl, N-octylcarbamoyl, N-cyclohexylcarbamoyl, N-tert-butylcarbamoyl, N-dodecylcarbamoyl, N- (3-dodecyloxypropyl) carbamoyl, N-octadecylcarbamoyl, N- {3 -(2,4-tert-pentylphenoxy) propyl} carbamoyl, N- (2-hexyldecyl) carbamoyl, N-phenylcarbamoyl, N- (4-dodecyloxyphenyl) carbamoyl, N- (2-chloro-5 Dodecyloxycarbo Butylphenyl) carbamoyl, N- naphthylcarbamoyl, N-3- pyridylcarbamoyl include N- benzylcarbamoyl.

The acyl group represented by Q ₂ is preferably an acyl group having 1 to 50 carbon atoms, more preferably 6 to 40 carbon atoms, such as formyl, acetyl, 2-methylpropanoyl, cyclohexylcarbonyl, octanoyl, 2 -Hexyldecanoyl, dodecanoyl, chloroacetyl, trifluoroacetyl, benzoyl, 4-dodecyloxybenzoyl, 2-hydroxymethylbenzoyl. The alkoxycarbonyl group represented by Q2 is preferably an alkoxycarbonyl group having 2 to 50 carbon atoms, more preferably 6 to 40 carbon atoms, such as methoxycarbonyl, ethoxycarbonyl, isobutyloxycarbonyl, cyclohexyloxycarbonyl, dodecyl. Examples include oxycarbonyl and benzyloxycarbonyl.

The aryloxycarbonyl group represented by Q ₂ is preferably an aryloxycarbonyl group having 7 to 50 carbon atoms, more preferably 7 to 40 carbon atoms, such as phenoxycarbonyl, 4-octyloxyphenoxycarbonyl, 2-hydroxy Examples thereof include methylphenoxycarbonyl and 4-dodecyloxyphenoxycarbonyl. The sulfonyl group represented by Q2 is preferably a sulfonyl group having 1 to 50 carbon atoms, more preferably 6 to 40 carbon atoms, such as methylsulfonyl, butylsulfonyl, octylsulfonyl, 2-hexadecylsulfonyl, 3-dodecyl. Examples include oxypropylsulfonyl, 2-octyloxy-5-tert-octylphenylsulfonyl, and 4-dodecyloxyphenylsulfonyl.

The sulfamoyl group represented by Q ₂ is preferably a sulfamoyl group having 0 to 50 carbon atoms, more preferably 6 to 40 carbon atoms, such as an unsubstituted sulfamoyl group, an N-ethylsulfamoyl group, N- (2- Ethylhexyl) sulfamoyl, N-decylsulfamoyl, N-hexadecylsulfamoyl, N- {3- (2-ethylhexyloxy) propyl} sulfamoyl, N- (2-chloro-5-dodecyloxycarbonylphenyl) sulfamoyl, N- (2-tetradecyloxyphenyl) sulfamoyl is mentioned. The group represented by Q ₂ may further have the group exemplified as the substituent of the 5- to 7-membered unsaturated ring represented by Q ₁ at a substitutable position. When it has two or more substituents, these substituents may be the same or different.

Next, a preferable range of the compound represented by formula (A-1) is described. Q ₁ is preferably a 5- to 6-membered unsaturated ring, such as a benzene ring, pyrimidine ring, 1,2,3-triazole ring, 1,2,4-triazole ring, tetrazole ring, 1,3,4-thiadiazole ring. 1,2,4-thiadiazole ring, 1,3,4-oxadiazole ring, 1,2,4-oxadiazole ring, thiazole ring, oxazole ring, isothiazole ring, isoxazole ring, and these rings Is more preferably a ring fused with a benzene ring or an unsaturated heterocycle. Q ₂ is preferably a carbamoyl group, particularly preferably a carbamoyl group having a hydrogen atom on a nitrogen atom.

  Formula (A-2)

In the general formula (A-2), R ₁ represents an alkyl group, an acyl group, an acylamino group, a sulfonamide group, an alkoxycarbonyl group, or a carbamoyl group. R ₂ represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an aryloxy group, an alkylthio group, an arylthio group, an acyloxy group, or a carbonate group. R ₃ and R ₄ each represents a group that can be substituted on the benzene ring mentioned in the example of the substituent of formula (A-1). R ₃ and R ₄ may be connected to each other to form a condensed ring.
R ₁ is preferably an alkyl group having 1 to 20 carbon atoms (for example, methyl group, ethyl group, isopropyl group, butyl group, tert-octyl group, cyclohexyl group, etc.), acylamino group (for example, acetylamino group, benzoylamino group, methyl group). Ureido group, 4-cyanophenylureido group, etc.), carbamoyl group (n-butylcarbamoyl group, N, N-diethylcarbamoyl group, phenylcarbamoyl group, 2-chlorophenylcarbamoyl group, 2,4-dichlorophenylcarbamoyl group, etc.) acylamino Groups (including ureido groups and urethane groups) are more preferred. R ₂ is preferably a halogen atom (more preferably a chlorine atom or a bromine atom), an alkoxy group (for example, a methoxy group, a butoxy group, an n-hexyloxy group, an n-decyloxy group, a cyclohexyloxy group, a benzyloxy group, etc.), aryl An oxy group (phenoxy group, naphthoxy group, etc.).
R ₃ is preferably a hydrogen atom, a halogen atom, or an alkyl group having 1 to 20 carbon atoms, and most preferably a halogen atom. R ₄ is preferably a hydrogen atom, an alkyl group, or an acylamino group, and more preferably an alkyl group or an acylamino group. Examples of these preferable substituents are the same as those for R ₁ . When R ₄ is an acylamino group, R ₄ is preferably linked to R ₃ to form a carbostyryl ring.

In the general formula (A-2), when R ₃ and R ₄ are connected to each other to form a condensed ring, a naphthalene ring is particularly preferable as the condensed ring. The same substituent as the example of a substituent quoted by general formula (A-1) may couple | bond with the naphthalene ring. When general formula (A-2) is a naphthol-based compound, R ₁ is preferably a carbamoyl group. Of these, a benzoyl group is particularly preferable. R ₂ is preferably an alkoxy group or an aryloxy group, and particularly preferably an alkoxy group.

  Hereinafter, preferred specific examples of the development accelerator of the present invention will be given. The present invention is not limited to these.

(Description of hydrogen bonding compound)
When the reducing agent in the present invention has an aromatic hydroxyl group (—OH) or an amino group (—NHR, R is a hydrogen atom or an alkyl group), particularly in the case of the aforementioned bisphenols, these groups and hydrogen bonds It is preferable to use together a non-reducing compound having a group capable of forming.
Examples of the group that forms a hydrogen bond with a hydroxyl group or an amino group include a phosphoryl group, a sulfoxide group, a sulfonyl group, a carbonyl group, an amide group, an ester group, a urethane group, a ureido group, a tertiary amino group, and a nitrogen-containing aromatic group. Can be mentioned. Among them, preferred are a phosphoryl group, a sulfoxide group, an amide group (however, it has no> N—H group and is blocked like> N—Ra (Ra is a substituent other than H)), a urethane group. (However, it has no> N—H group and is blocked like> N—Ra (Ra is a substituent other than H)), a ureido group (however, it has no> N—H group,> N-Ra (Ra is a substituent other than H).)
In the present invention, a particularly preferred hydrogen bonding compound is a compound represented by the following general formula (D).
Formula (D)

In the general formula (D), R ²¹ to R ²³ each independently represents an alkyl group, an aryl group, an alkoxy group, an aryloxy group, an amino group or a heterocyclic group, and these groups may be substituted even if they are unsubstituted. You may have.
When R ²¹ to R ²³ have a substituent, examples of the substituent include a halogen atom, an alkyl group, an aryl group, an alkoxy group, an amino group, an acyl group, an acylamino group, an alkylthio group, an arylthio group, a sulfonamide group, an acyloxy group, Examples thereof include an oxycarbonyl group, a carbamoyl group, a sulfamoyl group, a sulfonyl group, and a phosphoryl group. Preferred examples of the substituent include an alkyl group or an aryl group such as a methyl group, an ethyl group, an isopropyl group, a t-butyl group, and a t-octyl group. Group, phenyl group, 4-alkoxyphenyl group, 4-acyloxyphenyl group and the like.
Specific examples of the alkyl group represented by R ²¹ to R ²³ include a methyl group, an ethyl group, a butyl group, an octyl group, a dodecyl group, an isopropyl group, a t-butyl group, a t-amyl group, a t-octyl group, a cyclohexyl group, Examples include 1-methylcyclohexyl group, benzyl group, phenethyl group, 2-phenoxypropyl group and the like.
Examples of the aryl group include phenyl group, cresyl group, xylyl group, naphthyl group, 4-t-butylphenyl group, 4-t-octylphenyl group, 4-anisidyl group, and 3,5-dichlorophenyl group.
Alkoxy groups include methoxy, ethoxy, butoxy, octyloxy, 2-ethylhexyloxy, 3,5,5-trimethylhexyloxy, dodecyloxy, cyclohexyloxy, 4-methylcyclohexyloxy, benzyl An oxy group etc. are mentioned.
Examples of the aryloxy group include a phenoxy group, a cresyloxy group, an isopropylphenoxy group, a 4-t-butylphenoxy group, a naphthoxy group, and a biphenyloxy group.
Examples of the amino group include a dimethylamino group, a diethylamino group, a dibutylamino group, a dioctylamino group, an N-methyl-N-hexylamino group, a dicyclohexylamino group, a diphenylamino group, and an N-methyl-N-phenylamino group. .

R ²¹ to R ²³ are preferably an alkyl group, an aryl group, an alkoxy group, or an aryloxy group. In view of the effect of the present invention, at least one of R ²¹ to R ²³ is preferably an alkyl group or an aryl group, and more preferably two or more are an alkyl group or an aryl group. In addition, it is preferable that R ²¹ to R ²³ are the same group in that they can be obtained at low cost.
Specific examples of the hydrogen bonding compound including the compound of the general formula (D) in the present invention are shown below, but the present invention is not limited thereto.

Specific examples of the hydrogen bonding compound include those described in European Patent No. 1096310, JP-A No. 2002-156727, and JP-A No. 2002-318431 in addition to the above.
The compound of the general formula (D) of the present invention can be used in a light-sensitive material by being incorporated in a coating solution in the form of a solution, an emulsified dispersion, or a solid dispersion fine particle dispersion in the same manner as the reducing agent. It is preferable to use it as a product. The compound of the present invention forms a hydrogen-bonding complex with a compound having a phenolic hydroxyl group or an amino group in a solution state, and depending on the combination of the reducing agent and the compound of the general formula (D) of the present invention, It can be isolated in the crystalline state.
The use of the crystal powder isolated in this way as a solid dispersed fine particle dispersion is particularly preferable for obtaining stable performance. Further, a method in which the reducing agent and the compound of the general formula (D) of the present invention are mixed as a powder and complexed at the time of dispersion with a sand grinder mill or the like using an appropriate dispersant can be preferably used.
The compound of the general formula (D) of the present invention is preferably used in the range of 1 mol% to 200 mol%, more preferably in the range of 10 mol% to 150 mol%, still more preferably relative to the reducing agent. It is in the range of 20 mol% to 100 mol%.

(Description of silver halide)
1) Halogen composition The photosensitive silver halide used in the present invention is not particularly limited as a halogen composition, and is silver chloride, silver chlorobromide, silver bromide, silver iodobromide, silver iodochlorobromide, silver iodide. Can be used. Of these, silver bromide, silver iodobromide and silver iodide are preferred. The distribution of the halogen composition in the grains may be uniform, the halogen composition may be changed stepwise, or may be continuously changed. Further, silver halide grains having a core / shell structure can be preferably used. A preferable structure is a 2- to 5-fold structure, more preferably 2- to 4-fold core / shell particles. A technique for localizing silver bromide or silver iodide on the surface of silver chloride, silver bromide or silver chlorobromide grains can also be preferably used.

2) Grain Forming Methods Methods for forming photosensitive silver halide are well known in the art and are described, for example, in Research Disclosure No. 17029, June 1978, and US Pat. No. 3,700,458. In particular, a photosensitive silver halide is prepared by adding a silver supply compound and a halogen supply compound in gelatin or other polymer solution, and then mixed with an organic silver salt. Use the method. Further, the method described in paragraph Nos. 0217 to 0224 of JP-A No. 11-119374, and the methods described in JP-A Nos. 11-352627 and 2000-347335 are also preferable.

3) Grain size The grain size of the photosensitive silver halide is preferably small for the purpose of keeping the cloudiness after image formation low, specifically 0.20 μm or less, more preferably 0.01 μm or more and 0.15 μm or less. More preferably, it is 0.02 μm or more and 0.12 μm or less. The grain size here means the diameter when converted into a circular image having the same area as the projected area of silver halide grains (in the case of tabular grains, the projected area of the main plane).

4) Grain shape Examples of the shape of the silver halide grains include cubes, octahedrons, tabular grains, spherical grains, rod-like grains, and potato grains. In the present invention, cubic grains are particularly preferred. Grains with rounded corners of silver halide grains can also be preferably used. The surface index (Miller index) of the outer surface of the photosensitive silver halide grain is not particularly limited, but the ratio of the [100] plane having high spectral sensitization efficiency when the spectral sensitizing dye is adsorbed is high. preferable. The ratio is preferably 50% or more, more preferably 65% or more, and still more preferably 80% or more. The ratio of the Miller index [100] plane is determined by T.T. Tani; Imaging Sci. 29, 165 (1985).

5) Heavy metal The photosensitive silver halide grain of the present invention may contain a metal or metal complex of Group 8 to Group 10 of the Periodic Table (showing Groups 1 to 18). As the central metal of the group 8 to group 10 metal or metal complex of the periodic table, rhodium, ruthenium and iridium are preferable. One kind of these metal complexes may be used, or two or more kinds of complexes of the same metal and different metals may be used in combination. The preferred content is in the range of 1 × 10 ⁻⁹ mol to 1 × 10 ⁻³ mol with ^respect to 1 mol of silver. These heavy metals and metal complexes and methods for adding them are described in JP-A-7-225449, JP-A-11-65021, paragraphs 0018 to 0024, and JP-A-11-119374, paragraphs 0227 to 0240.

In the present invention, silver halide grains in which a hexacyano metal complex is present on the outermost surface of the grains are preferred. The hexacyano metal complexes include [Fe (CN) ₆ ] ⁴⁻ , [Fe (CN) ₆ ] ³⁻ , [Ru (CN) ₆ ] ⁴⁻ , [Os (CN) ₆ ] ⁴⁻ , [Co ( CN) ₆ ] ³⁻ , [Rh (CN) ₆ ] ³⁻ , [Ir (CN) ₆ ] ³⁻ , [Cr (CN) ₆ ] ³⁻ , [Re (CN) ₆ ] ^{3− and the} like. .
In the present invention, a hexacyano Fe complex is preferred.

  The hexacyano metal complex is present in the form of ions in aqueous solution, so the counter cation is not important, but it is easy to mix with water and is suitable for precipitation of silver halide emulsions. Sodium ion, potassium ion, rubidium It is preferable to use alkali metal ions such as ions, cesium ions, and lithium ions, ammonium ions, and alkylammonium ions (for example, tetramethylammonium ions, tetraethylammonium ions, tetrapropylammonium ions, tetra (n-butyl) ammonium ions).

  In addition to water, the hexacyano metal complex is miscible with a mixed solvent or gelatin with an appropriate organic solvent miscible with water (for example, alcohols, ethers, glycols, ketones, esters, amides, etc.). Can be added.

The addition amount of the hexacyano metal complex is preferably 1 × 10 ⁻⁵ mol or more and 1 × 10 ⁻² mol or less, more preferably 1 × 10 ⁻⁴ mol or more and 1 × 10 ⁻³ mol or less per mol of silver.

  In order for the hexacyano metal complex to be present on the outermost surface of the silver halide grain, the chalcogen sensitization of sulfur sensitization, selenium sensitization and tellurium sensitization is completed after the addition of the aqueous silver nitrate solution used for grain formation. It is added directly before the completion of the preparation step before the chemical sensitization step for performing noble metal sensitization such as sensitization and gold sensitization, during the washing step, during the dispersion step, or before the chemical sensitization step. In order to prevent the silver halide fine grains from growing, it is preferable to add the hexacyano metal complex immediately after the grain formation, and it is preferable to add it before the completion of the preparation step.

  The addition of the hexacyano metal complex may be started after adding 96% by mass of the total amount of silver nitrate to be added to form grains, more preferably starting after adding 98% by mass, The addition of 99% by mass is particularly preferable.

  When these hexacyanometal complexes are added after the addition of the aqueous silver nitrate solution just before the completion of grain formation, they can be adsorbed on the outermost surface of the silver halide grains, and most of them form slightly soluble salts with silver ions on the grain surface. To do. Since this silver salt of hexacyanoiron (II) is a less soluble salt than AgI, it is possible to prevent re-dissolution by fine particles and to produce silver halide fine particles having a small particle size. .

Further, regarding a metal atom (for example, [Fe (CN) ₆ ] ⁴⁻ ), a silver halide emulsion desalting method and a chemical sensitization method which can be contained in the silver halide grains used in the present invention, JP-A No. 11-101. No. 84574, paragraph numbers 0046 to 0050, JP-A No. 11-65021, paragraph numbers 0025 to 0031, and JP-A No. 11-119374, paragraph numbers 0242 to 0250.

6) Gelatin As the gelatin contained in the photosensitive silver halide emulsion used in the present invention, various gelatins can be used. It is necessary to maintain a good dispersion state of the photosensitive silver halide emulsion in the coating solution containing an organic silver salt, and gelatin having a molecular weight of 10,000 to 1,000,000 is preferably used. It is also preferable to phthalate the gelatin substituent. These gelatins may be used at the time of grain formation or at the time of dispersion after desalting, but are preferably used at the time of grain formation.

7) Sensitizing Dye Sensitizing dyes applicable to the present invention are those that can spectrally sensitize silver halide grains in a desired wavelength region when adsorbed on silver halide grains, and are suitable for the spectral characteristics of the exposure light source. Sensitizing dyes with sensitivity can be advantageously selected. Regarding the sensitizing dye and the addition method, paragraphs 0103 to 0109 of JP-A No. 11-65021, compounds represented by the general formula (II) of JP-A No. 10-186572, and general formulas (I of JP-A No. 11-119374) ) And dyes described in paragraph No. 0106, U.S. Pat. Nos. 5,510,236 and 3,871,887, Example 5, JP-A-2-96131, JP-A-59-48753 No. 19, line 38 to page 20, line 35 of JP-A-0803764A1, JP-A No. 2001-272747, JP-A No. 2001-290238, JP-A No. 2002-23306, etc. It is described in. These sensitizing dyes may be used alone or in combination of two or more.
In the present invention, the time when the sensitizing dye is added to the silver halide emulsion is preferably the time from the desalting step to the coating, and more preferably the time from desalting to the end of chemical ripening.
The addition amount of the sensitizing dye in the present invention can be set to a desired amount in accordance with sensitivity and fogging performance, but is preferably 10 ⁻⁶ to 1 mol, more preferably 1 mol per mol of silver halide in the photosensitive layer. Is 10 ⁻⁴ to 10 ⁻¹ mol.

  In the present invention, a supersensitizer can be used to improve spectral sensitization efficiency. As the supersensitizer used in the present invention, European Patent Publication No. 587,338, US Pat. Nos. 3,877,943, 4,873,184, JP-A-5-341432, 11- 109547, 10-111543, etc. are mentioned.

8) Chemical Sensitization The photosensitive silver halide grain in the invention is preferably chemically sensitized by sulfur sensitizing method, selenium sensitizing method or tellurium sensitizing method. As the compound preferably used in the sulfur sensitization method, selenium sensitization method, and tellurium sensitization method, known compounds such as compounds described in JP-A-7-128768 can be used. In the present invention, tellurium sensitization is particularly preferred, and compounds described in the literature described in paragraph No. 0030 of JP-A-11-65021, general formulas (II), (III), (IV) in JP-A-5-313284 The compound shown by is more preferable.

  The photosensitive silver halide grains in the present invention are preferably chemically sensitized by gold sensitization alone or in combination with the chalcogen sensitization described above. As the gold sensitizer, the valence of gold is preferably +1 or +3, and the gold sensitizer is preferably a gold compound that is usually used. Typical examples include chloroauric acid, bromoauric acid, potassium chloroaurate, potassium bromoaurate, auric trichloride, potassium auric thiocyanate, potassium iodoaurate, tetracyanoauric acid, ammonium aurothiocyanate, pyridyltrichlorogold. Etc. are preferable. Further, gold sensitizers described in US Pat. No. 5,858,637 and JP-A-2002-278016 are also preferably used.

In the present invention, chemical sensitization can be performed at any time after particle formation and before coating. After desalting, (1) before spectral sensitization, (2) simultaneously with spectral sensitization, (3) spectral After sensitization, there may be (4) immediately before application.
The amount of sulfur, selenium and tellurium sensitizers used in the present invention varies depending on the silver halide grains used, chemical ripening conditions, etc., but is preferably 10 ⁻⁸ to 10 ⁻² mol per mol of silver halide, preferably About 10 ⁻⁷ to 10 ⁻³ mol is used.
The amount of the gold sensitizer added varies depending on various conditions, but as a guide, it is 10 ⁻⁷ mol to 10 ⁻³ mol, more preferably 10 ⁻⁶ mol to 5 × 10 ⁻⁴ mol per mol of silver halide. .
The conditions for chemical sensitization in the present invention are not particularly limited, but the pH is 5 to 8, the pAg is 6 to 11, and the temperature is about 40 to 95 ° C.
A thiosulfonic acid compound may be added to the silver halide emulsion used in the present invention by the method described in European Patent Publication No. 293,917.

  A reducing agent is preferably used for the photosensitive silver halide grains in the present invention. As specific compounds for the reduction sensitization, ascorbic acid and thiourea dioxide are preferable, and in addition, stannous chloride, aminoiminomethanesulfinic acid, hydrazine derivatives, borane compounds, silane compounds, polyamine compounds, and the like are preferably used. . The reduction sensitizer may be added at any stage in the photosensitive emulsion production process from crystal growth to the preparation process immediately before coating. Further, reduction sensitization is preferably carried out by ripening while maintaining the pH of the emulsion at 7 or more or pAg at 8.3 or less, and reduction sensitization by introducing a single addition portion of silver ions during grain formation. It is also preferable to do.

9) Compound in which 1-electron oxidant produced by 1-electron oxidation can emit 1 electron or more electrons In the photothermographic material of the present invention, 1-electron oxidant produced by 1-electron oxidation is 1 electron or 1 electron or more. It is preferable to contain a compound capable of emitting more electrons.
The compound can be used alone or in combination with the above-described various chemical sensitizers, and can increase the sensitivity of silver halide.

  The one-electron oxidant produced by one-electron oxidation contained in the photothermographic material of the present invention is a compound selected from the following types 1 to 5 that can emit one or more electrons.

(Type 1)
A compound in which a one-electron oxidant produced by one-electron oxidation can further emit two or more electrons with a subsequent bond cleavage reaction.
(Type 2)
The one-electron oxidant produced by one-electron oxidation is a compound capable of releasing another electron with subsequent bond cleavage reaction, and has two or more adsorptive groups to silver halide in the same molecule. Compound.
(Type 3)
A compound capable of emitting one or more electrons after a one-electron oxidant produced by one-electron oxidation undergoes a subsequent bond formation process.
(Type 4)
A compound capable of emitting one or more electrons after a one-electron oxidant produced by one-electron oxidation undergoes a subsequent intramolecular ring-cleaving reaction.
(Type 5)
In the compound represented by XY, X represents a reducing group, Y represents a leaving group, and a one-electron oxidant formed by one-electron oxidation of the reducing group represented by X is followed by XY A compound capable of releasing Y by releasing Y with a bond cleavage reaction and releasing another electron therefrom.

  Preferred among the compounds of types 1 and 3 to 5 above are “compounds having an adsorptive group to silver halide in the molecule” or “partial structure of spectral sensitizing dye in the molecule”. Compound ". More preferred is a “compound having an adsorptive group to silver halide in the molecule”. The compounds of types 1 to 4 are more preferably “compounds having a nitrogen-containing heterocyclic group substituted with two or more mercapto groups as an adsorptive group”.

The compounds of types 1 to 5 will be described in detail.
In the type 1 compound, “bond cleavage reaction” specifically means cleavage of bonds between carbon-carbon, carbon-silicon, carbon-hydrogen, carbon-boron, carbon-tin, and carbon-germanium elements, These may be further accompanied by carbon-hydrogen bond cleavage. A type 1 compound is a compound capable of emitting two or more (preferably three or more) electrons for the first time after a one-electron oxidation to form a one-electron oxidant, followed by a bond cleavage reaction.

  A preferable compound among the compounds of type 1 is represented by general formula (A), general formula (B), general formula (1), general formula (2), or general formula (3).

In the general formula (A), RED ₁₁ represents a reducing group that can be oxidized by one electron, and L ₁₁ represents a leaving group. R ₁₁₂ represents a hydrogen atom or a substituent. R ₁₁₁ together with carbon atom (C) and RED ₁₁ can form a cyclic structure corresponding to a tetrahydro, hexahydro or octahydro form of a 5- or 6-membered aromatic ring (including aromatic heterocycle). Represents a metal atomic group.

In the general formula (B), RED ₁₂ represents a reducing group that can be oxidized by one electron, and L ₁₂ represents a leaving group. R ₁₂₁ and R ₁₂₂ each represent a hydrogen atom or a substituent. ED ₁₂ represents an electron donating group. In the general formula (B), R ₁₂₁ and RED ₁₂ , R ₁₂₁ and R ₁₂₂ , or ED ₁₂ and RED ₁₂ may be bonded to each other to form a cyclic structure.

These compounds represented by the general formula (A) or the general formula (B) spontaneously bond and cleave L ₁₁ or L ₁₂ after the reducing group represented by RED ₁₁ or RED ₁₂ is oxidized by one electron. It is a compound that can release two or more, preferably three or more electrons in association with separation by reaction.

In the general formula (1), Z ₁ represents an atomic group capable of forming a 6-membered ring together with a nitrogen atom and two carbon atoms of a benzene ring, R ₁ , R ₂ and R _N1 each represents a hydrogen atom or a substituent, X ₁ represents a substituent substitutable on the benzene ring, m ₁ represents an integer of 0 to 3, and L ₁ represents a leaving group. In the general formula (2), ED ₂₁ represents an electron donating group, R ₁₁ , R ₁₂ , R _N21 , R ₁₃ , and R ₁₄ each represents a hydrogen atom or a substituent, and X ₂₁ represents a substituent that can be substituted on the benzene ring. Represents a group, m ₂₁ represents an integer of 0 to 3, and L ₂₁ represents a leaving group. R _N21 , R ₁₃ , R ₁₄ , X ₂₁ and ED ₂₁ may be bonded to each other to form a cyclic structure. In the general formula (3), R ₃₂ , R ₃₃ , R ₃₁ , R _N31 , R _a and R _b each represent a hydrogen atom or a substituent, and L ₃₁ represents a leaving group. However, when R _N31 represents a group other than an aryl group, R _a and R _b are bonded to each other to form an aromatic ring.

After these compounds are oxidized by one electron, L ₁ , L ₂₁ , or L ₃₁ is spontaneously released by a bond cleavage reaction, and accordingly, two or more electrons, preferably three or more, can be emitted. A compound.

Hereinafter, the compound represented by the general formula (A) will be described in detail first.
The reducing group that can be oxidized by one electron represented by RED ₁₁ in the general formula (A) is a group that can form a specific ring by binding to R ₁₁₁ described later. Specifically, the following monovalent group: And a divalent group obtained by removing one hydrogen atom at a suitable position for ring formation. For example, alkylamino group, arylamino group (anilino group, naphthylamino group, etc.), heterocyclic amino group (benzthiazolylamino group, pyrrolylamino group, etc.), alkylthio group, arylthio group (phenylthio group, etc.), heterocyclic thio Group, alkoxy group, aryloxy group (phenoxy group etc.), heterocyclic oxy group, aryl group (phenyl group, naphthyl group, anthranyl group etc.), aromatic or non-aromatic heterocyclic group (5-membered to 7-membered) A monocyclic or condensed heterocyclic ring containing at least one heteroatom among nitrogen atom, sulfur atom, oxygen atom and selenium atom. Specific examples thereof include, for example, a tetrahydroquinoline ring, a tetrahydroisoquinoline ring, and a tetrahydroquinoxaline ring. , Tetrahydroquinazoline ring, indoline ring, indole ring, indazo Ring, carbazole ring, phenoxazine ring, phenothiazine ring, benzothiazoline ring, pyrrole ring, imidazole ring, thiazoline ring, piperidine ring, pyrrolidine ring, morpholine ring, benzimidazole ring, benzimidazoline ring, benzoxazoline ring, methylenedioxyphenyl (Hereinafter, RED ₁₁ will be described as a monovalent group name for convenience). RED ₁₁ may have a substituent.

  In the present invention, the substituent means a substituent selected from the following groups unless otherwise specified. Halogen atoms, alkyl groups (including aralkyl groups, cycloalkyl groups, active methine groups, etc.), alkenyl groups, alkynyl groups, aryl groups, heterocyclic groups (regardless of the position of substitution), quaternized nitrogen atoms Heterocyclic groups (eg pyridinio group, imidazolio group, quinolinio group, isoquinolinio group), acyl group, alkoxycarbonyl group, aryloxycarbonyl group, carbamoyl group, carboxy group or salt thereof, sulfonylcarbamoyl group, acylcarbamoyl group, sulfa Moylcarbamoyl group, carbazoyl group, oxalyl group, oxamoyl group, cyano group, carbonimidoyl group, thiocarbamoyl group, hydroxy group, alkoxy group (including groups containing ethyleneoxy group or propyleneoxy group unit repeatedly), aryloxy group , Telocyclic oxy group, acyloxy group, (alkoxy or aryloxy) carbonyloxy group, carbamoyloxy group, sulfonyloxy group, amino group, (alkyl, aryl, or heterocyclic) amino group, acylamino group, sulfonamide group, ureido group Thioureido group, imide group, (alkoxy or aryloxy) carbonylamino group, sulfamoylamino group, semicarbazide group, thiosemicarbazide group, hydrazino group, ammonio group, oxamoylamino group, (alkyl or aryl) sulfonylureido group, Acylureido group, acylsulfamoylamino group, nitro group, mercapto group, (alkyl, aryl, or heterocyclic) thio group, (alkyl or aryl) sulfonyl group, (alkyl or aryl) Rufiniru group, a sulfo group or a salt thereof, sulfamoyl group, sulfonylsulfamoyl group or a salt thereof, phosphoric acid amide or a group containing a phosphoric acid ester structure and so forth. These substituents may be further substituted with these substituents.

RED ₁₁ is preferably an alkylamino group, an arylamino group, a heterocyclic amino group, an aryl group, an aromatic or non-aromatic heterocyclic group, more preferably an arylamino group (particularly an anilino group), an aryl group ( Especially a phenyl group). When these have a substituent, the substituent is preferably a halogen atom, an alkyl group, an alkoxy group, a carbamoyl group, a sulfamoyl group, an acylamino group, or a sulfonamide group.
However, when RED ₁₁ represents an aryl group, the aryl group preferably has at least one “electron-donating group”. Here, the “electron donating group” means a hydroxy group, an alkoxy group, a mercapto group, a sulfonamide group, an acylamino group, an alkylamino group, an arylamino group, a heterocyclic amino group, an active methine group, and a nitrogen atom in the ring. 5-membered, monocyclic or condensed, electron-rich aromatic heterocyclic group (for example, indolyl group, pyrrolyl group, imidazolyl group, benzimidazolyl group, thiazolyl group, benzthiazolyl group, indazolyl group) containing at least one, nitrogen A non-aromatic nitrogen-containing heterocyclic group (a group that can also be called a cyclic amino group such as a pyrrolidinyl group, an indolinyl group, a piperidinyl group, a piperazinyl group, or a morpholino group) substituted with an atom. Here, the active methine group means a methine group substituted by two “electron-withdrawing groups”, and the “electron-withdrawing group” means an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, It means a carbamoyl group, an alkylsulfonyl group, an arylsulfonyl group, a sulfamoyl group, a trifluoromethyl group, a cyano group, a nitro group, or a carbonimidoyl group. Here, the two electron withdrawing groups may be bonded to each other to form a cyclic structure.

In the general formula (A), L ₁₁ is specifically a carboxy group or a salt thereof, a silyl group, a hydrogen atom, a triarylboron anion, a trialkylstannyl group, a trialkylgermyl group, or —CR _C1 R _C2 R Represents the _C3 group. Here, the silyl group specifically represents a trialkylsilyl group, an aryldialkylsilyl group, a triarylsilyl group, or the like, and may have an arbitrary substituent.

When L ₁₁ represents a salt of a carboxy group, examples of counter ions that form the salt include alkali metal ions, alkaline earth metal ions, heavy metal ions, ammonium ions, phosphonium ions, and preferably alkali metal ions or ammonium ions. Alkali metal ions (particularly Li ⁺ , Na ⁺ , K ⁺ ions) are most preferred.

When L ₁₁ represents a —CR _C1 R _C2 R _C3 group, R _C1 , R _C2 and R _C3 are each independently a hydrogen atom, alkyl group, aryl group, heterocyclic group, alkylthio group, arylthio group, alkyl Represents an amino group, an arylamino group, a heterocyclic amino group, an alkoxy group, an aryloxy group, or a hydroxy group, which may be bonded to each other to form a cyclic structure and further have an optional substituent. Also good. However, when one of R _C1 , R _C2 and R _C3 represents a hydrogen atom or an alkyl group, the remaining two do not represent a hydrogen atom or an alkyl group. R _C1 , R _C2 and R _C3 are preferably each independently an alkyl group, aryl group (particularly phenyl group), alkylthio group, arylthio group, alkylamino group, arylamino group, heterocyclic group, alkoxy group, hydroxy group Specific examples thereof include phenyl group, p-dimethylaminophenyl group, p-methoxyphenyl group, 2,4-dimethoxyphenyl group, p-hydroxyphenyl group, methylthio group, phenylthio group, phenoxy group, Examples include methoxy group, ethoxy group, dimethylamino group, N-methylanilino group, diphenylamino group, morpholino group, thiomorpholino group, hydroxy group and the like. Examples of the case where they are bonded to each other to form a cyclic structure include 1,3-dithiolan-2-yl group, 1,3-dithian-2-yl group, N-methyl-1,3-thiazolidine-2 -Yl group, N-benzyl-benzothiazolidin-2-yl group and the like.
-CR _C1 R _C2 R _C3 group represents the same group as the residue obtained by removing L ₁₁ from general formula (A) as a result of selection within the ranges described above for R _C1 , R _C2 and R _C3 , respectively. Is also preferred.

In the general formula (A), L ₁₁ is preferably a carboxy group or a salt thereof, and a hydrogen atom. More preferably, it is a carboxy group or a salt thereof.

When L ₁₁ represents a hydrogen atom, the compound represented by the general formula (A) preferably has a base moiety inherent in the molecule. By the action of this base moiety, after the compound represented by the general formula (A) is oxidized, the hydrogen atom represented by L ₁₁ is deprotonated and further electrons are emitted therefrom.

Here, the base is specifically a conjugate base of an acid having a pKa of about 1 to about 10. For example, nitrogen-containing heterocycles (pyridines, imidazoles, benzimidazoles, thiazoles, etc.), anilines, trialkylamines, amino groups, carbon acids (active methylene anions, etc.), thioacetic acid anions, carboxylates (- COO ⁻ ), sulfate (—SO ₃ ⁻ ), amine oxide (> N ⁺ (O ⁻ ) —) and the like. Preferably, it is a conjugate base of an acid having a pKa of about 1 to about 8, more preferably carboxylate, sulfate, or amine oxide, and particularly preferably carboxylate. When these bases have anions, they may have counter cations, examples of which include alkali metal ions, alkaline earth metal ions, heavy metal ions, ammonium ions, phosphonium ions and the like. These bases are linked to the compound represented by the general formula (A) at an arbitrary position. The position at which these base sites are bonded may be any of RED ₁₁ , R ₁₁₁ and R _{112 in} the general formula (A), and may be linked to a substituent of these groups.

In the general formula (A), R ₁₁₂ represents a hydrogen atom or a substituent that can be substituted with a carbon atom. However, R ₁₁₂ does not represent the same group as L ₁₁ .
_R112 is preferably a hydrogen atom, an alkyl group, an aryl group (such as a phenyl group), an alkoxy group (such as a methoxy group, an ethoxy group, or a benzyloxy group), a hydroxy group, an alkylthio group (such as a methylthio group or a butylthio group), or an amino group , An alkylamino group, an arylamino group, and a heterocyclic amino group, more preferably a hydrogen atom, an alkyl group, an alkoxy group, a hydroxy group, a phenyl group, and an alkylamino group.

In the general formula (A), the cyclic structure formed by R ₁₁₁ is a ring structure corresponding to a tetrahydro, hexahydro or octahydro form of a 5-membered or 6-membered aromatic ring (including aromatic heterocycle). The hydro form means a ring structure in which a carbon-carbon double bond (or carbon-nitrogen double bond) inherent in an aromatic ring (including an aromatic heterocycle) is partially hydrogenated, The body means two structures, the hexahydro form means three, and the octahydro form means four structures in which carbon-carbon double bonds (or carbon-nitrogen double bonds) are hydrogenated. By being hydrogenated, the aromatic ring becomes a partially hydrogenated non-aromatic ring structure.
Specifically, pyrrolidine ring, imidazolidine ring, thiazolidine ring, pyrazolidine ring and oxazolidine ring, piperidine ring, tetrahydropyridine ring, tetrahydropyrimidine ring, piperazine ring, tetralin ring, tetrahydroquinoline ring, tetrahydroisoquinoline ring, tetrahydroquinazoline ring, And tetrahydroquinoxaline ring, tetrahydrocarbazole ring, octahydrophenanthridine ring and the like. These ring structures may have an arbitrary substituent.

More preferably, the cyclic structure formed by R ₁₁₁ is more preferably a pyrrolidine ring, imidazolidine ring, piperidine ring, tetrahydropyridine ring, tetrahydropyrimidine ring, piperazine ring, tetrahydroquinoline ring, tetrahydroisoquinoline ring, tetrahydroquinazoline ring, tetrahydroquinoxaline ring, tetrahydroquinone ring Carbazole ring, particularly preferably pyrrolidine ring, piperidine ring, piperazine ring, tetrahydropyridine ring, tetrahydroquinoline ring, tetrahydroisoquinoline ring, tetrahydroquinazoline ring, tetrahydroquinoxaline ring, most preferably pyrrolidine ring, piperidine ring, tetrahydro ring A pyridine ring, a tetrahydroquinoline ring, and a tetrahydroisoquinoline ring.

In the general formula (B), RED ₁₂ and L ₁₂ are groups having the same meanings as RED ₁₁ and L ₁₁ in the general formula (A), respectively, and preferred ranges thereof are also the same. However, RED ₁₂ is a monovalent group except for the case where the following cyclic structure is formed, and specific examples include groups having the monovalent group name described in RED ₁₁ . R ₁₂₁ and R ₁₂₂ are groups having the same meaning as R ₁₁₂ in the general formula (A), and preferred ranges thereof are also the same. ED ₁₂ represents an electron donating group. R ₁₂₁ and RED ₁₂ , R ₁₂₁ and R ₁₂₂ , or ED ₁₂ and RED ₁₂ may be bonded to each other to form a cyclic structure.

The electron donating group represented by ED ₁₂ in the general formula (B) is the same as the electron donating group described as a substituent when RED ₁₁ represents an aryl group. ED ₁₂ is preferably a hydroxy group, an alkoxy group, a mercapto group, a sulfonamide group, an alkylamino group, an arylamino group, an active methine group, or a 5-membered monocyclic or condensed ring containing at least one nitrogen atom in the ring. An electron-excess aromatic heterocyclic group, a non-aromatic nitrogen-containing heterocyclic group substituted with a nitrogen atom, and a phenyl group substituted with these electron-donating groups, and further a hydroxy group, a mercapto group, a sulfonamide group, An alkylamino group, an arylamino group, an active methine group, a non-aromatic nitrogen-containing heterocyclic group substituted with a nitrogen atom, and a phenyl group substituted with these electron-donating groups (for example, p-hydroxyphenyl group, p-dialkylamino) A phenyl group, an o, p-dialkoxyphenyl group, and the like).

In the general formula (B), R ₁₂₁ and RED ₁₂ , R ₁₂₂ and R ₁₂₁ , or ED ₁₂ and RED ₁₂ may be bonded to each other to form a cyclic structure. The cyclic structure formed here is a non-aromatic carbocyclic or heterocyclic ring, which is a 5-membered to 7-membered monocyclic or condensed ring, and is a substituted or unsubstituted cyclic structure. When R ₁₂₁ and RED ₁₂ form a ring structure, specific examples thereof include pyrroline ring, imidazoline ring, thiazoline in addition to the examples of the cyclic structure formed by R ₁₁₁ in formula (A). Ring, pyrazoline ring, oxazoline ring, indane ring, morpholine ring, indoline ring, tetrahydro-1,4-oxazine ring, 2,3-dihydrobenzo-1,4-oxazine ring, tetrahydro-1,4-thiazine ring, 2 , 3-dihydrobenzo-1,4-thiazine ring, 2,3-dihydrobenzofuran ring, 2,3-dihydrobenzothiophene ring and the like. When ED ₁₂ and RED ₁₂ form a ring structure, ED ₁₂ preferably represents an amino group, an alkylamino group, or an arylamino group. Specific examples of the formed ring structure include a tetrahydropyrazine ring, a piperazine ring, A tetrahydroquinoxaline ring, a tetrahydroisoquinoline ring, etc. are mentioned. When R ₁₂₂ and R ₁₂₁ form a ring structure, specific examples thereof include a cyclohexane ring and a cyclopentane ring.

Next, general formulas (1) to (3) will be described.
In the general formulas (1) to (3), R ₁ , R ₂ , R ₁₁ , R ₁₂ and R ₃₁ are groups having the same meaning as R _{112 in the} general formula (A), and preferred ranges thereof are also the same. L ₁ , L ₂₁ and L ₃₁ represent the same leaving groups as those exemplified as specific examples in the description of L _{11 in the} general formula (A), and preferred ranges thereof are also the same. The substituents represented by X ₁ and X ₂₁ are the same as the examples of the substituent when RED ₁₁ of the general formula (A) has a substituent, and the preferred range is also the same. m ₁ and m ₂₁ are preferably integers of 0 to 2, more preferably 0 or 1.

When R _N1 , R _N21 , and R _N31 represent a substituent, the substituent is preferably an alkyl group, an aryl group, or a heterocyclic group, and these may further have an arbitrary substituent. R _N1 , R _N21 and R _N31 are preferably a hydrogen atom, an alkyl group or an aryl group, more preferably a hydrogen atom or an alkyl group.

When R ₁₃ , R ₁₄ , R ₃₃ , R _a and R _b represent a substituent, the substituent is preferably an alkyl group, aryl group, acyl group, alkoxycarbonyl group, carbamoyl group, cyano group, alkoxy group, acylamino Group, sulfonamido group, ureido group, thioureido group, alkylthio group, arylthio group, alkylsulfonyl group, arylsulfonyl group, sulfamoyl group and the like.

The 6-membered ring formed by Z ₁ in the general formula (1) is a non-aromatic heterocycle condensed with the benzene ring of the general formula (1). Specifically, as a ring structure including the condensed benzene ring, A tetrahydroquinoline ring, a tetrahydroquinoxaline ring, and a tetrahydroquinazoline ring, preferably a tetrahydroquinoline ring and a tetrahydroquinoxaline ring. These may have a substituent.

In the general formula (2), ED ₂₁ is a group having the same meaning as ED _{12 in the} general formula (B), and the preferred range thereof is also the same.

In the general formula (2), any two of R _N21 , R ₁₃ , R ₁₄ , X ₂₁ and ED ₂₁ may be bonded to each other to form a cyclic structure. Here, the cyclic structure formed by combining R _N21 and X ₂₁ is preferably a 5- to 7-membered non-aromatic carbocyclic or heterocyclic ring condensed with a benzene ring. , Tetrahydroquinoline ring, tetrahydroquinoxaline ring, indoline ring, 2,3-dihydro-5,6-benzo-1,4-thiazine ring and the like. Preferred are a tetrahydroquinoline ring, a tetrahydroquinoxaline ring and an indoline ring.

In the general formula (3), when R _N31 represents a group other than an aryl group, R _a and R _b are bonded to each other to form an aromatic ring. Here, the aromatic ring is an aryl group (for example, a phenyl group or a naphthyl group) and an aromatic heterocyclic group (for example, a pyridine ring group, a pyrrole ring group, a quinoline ring group, or an indole ring group), and an aryl group is preferable. The aromatic ring group may have an arbitrary substituent.
In the general formula (3), R _a and R _b are preferably bonded to each other to form an aromatic ring (particularly a phenyl group).

Formula (3) in R ₃₂ is preferably a hydrogen atom, an alkyl group, an aryl group, hydroxy group, an alkoxy group, a mercapto group, and the like amino group, wherein when R ₃₂ represents a hydroxy group, R ₃₃ at the same time A case of representing an “electron withdrawing group” is also a preferred example. Here, the “electron withdrawing group” is the same as described above, and an acyl group, an alkoxycarbonyl group, a carbamoyl group, and a cyano group are preferable.

Next, the type 2 compound will be described.
In the type 2 compound, “bond cleavage reaction” means carbon-carbon, carbon-silicon, carbon-hydrogen, carbon-boron, carbon-tin, carbon-germanium bond cleavage, and carbon-hydrogen. This may be accompanied by cleavage of the bond.

  The type 2 compound is a compound having two or more (preferably 2 to 6, more preferably 2 to 4) adsorptive groups to silver halide in the molecule. More preferred is a compound having a nitrogen-containing heterocyclic group substituted with two or more mercapto groups as an adsorptive group. The number of adsorptive groups is preferably 2-6, more preferably 2-4. The adsorptive group will be described later.

  A preferable compound among the compounds of type 2 is represented by the general formula (C).

Here, the compound represented by the general formula (C) has a structure in which, after the reducing group represented by RED ₂ is oxidized by one electron, L ₂ is spontaneously released by a bond cleavage reaction. It is a compound that can emit one electron.

In the general formula (C), RED ₂ represents a group having the same meaning as RED _{12 in the} general formula (B), and its preferred range is also the same. L ₂ represents a group having the same meaning as described for L ₁₁ in the general formula (A), and its preferred range is also the same. When L ₂ represents a silyl group, the compound is a compound having, as an adsorptive group, a nitrogen-containing heterocyclic group substituted with two or more mercapto groups in the molecule. R ₂₁ and R ₂₂ represent a hydrogen atom or a substituent, and these are groups having the same meaning as R _{112 in} formula (A), and their preferred ranges are also the same. RED ₂ and R ₂₁ may be bonded to each other to form a ring structure.

  The ring structure formed here is a 5-membered to 7-membered monocyclic or condensed, non-aromatic carbocycle or heterocycle, which may have a substituent. However, the ring structure is not a ring structure corresponding to a tetrahydro, hexahydro or octahydro form of an aromatic ring or an aromatic heterocycle. The ring structure is preferably a ring structure corresponding to a dihydro form of an aromatic ring or an aromatic heterocycle, and specific examples thereof include, for example, a 2-pyrroline ring, a 2-imidazoline ring, a 2-thiazoline ring, 1,2- Dihydropyridine ring, 1,4-dihydropyridine ring, indoline ring, benzimidazoline ring, benzothiazoline ring, benzoxazoline ring, 2,3-dihydrobenzothiophene ring, 2,3-dihydrobenzofuran ring, benzo-α-pyran ring, 1 , 2-dihydroquinoline ring, 1,2-dihydroquinazoline ring, 1,2-dihydroquinoxaline ring and the like, preferably 2-imidazoline ring, 2-thiazoline ring, indoline ring, benzoimidazoline ring, benzothiazoline ring, Benzoxazoline ring, 1,2-dihydropyridine ring, 1,2-dihydroquino Down ring, 1,2-dihydro-quinazoline ring, and the like 1,2-dihydro-quinoxaline ring, indoline ring, benzimidazoline ring, a benzothiazoline ring, 1,2-dihydroquinoline ring is more preferable, indoline ring is particularly preferred.

Next, the compound of type 3 will be described.
In the type 3 compound, “bond formation process” means formation of an interatomic bond such as carbon-carbon, carbon-nitrogen, carbon-sulfur, carbon-oxygen and the like.

  The compound of type 3 is preferably a reactive group site (carbon-carbon double bond site, carbon-carbon triple bond site, fragrance) in which a one-electron oxidant formed by one-electron oxidation coexists in the molecule. And a non-aromatic heterocyclic group part of a benzo-condensed ring) to form a bond and then emit one electron or more electrons.

More specifically, a type 3 compound has a one-electron oxidant formed by one-electron oxidation (a cation radical species or a neutral radical species produced by elimination of a proton therefrom) in the same molecule. It reacts with the coexisting reactive group, forms a bond, and generates a radical species having a new ring structure in the molecule. This radical species has a feature that electrons of the second electron are emitted directly or with elimination of protons.
And in some of the type 3 compounds, the two-electron oxidant thus produced is then subjected to a hydrolysis reaction in some cases, and in some cases tautomerization with direct proton transfer. There is a case in which one or more electrons, usually two or more electrons are emitted from the oxidization reaction. Alternatively, those having the ability to emit one or more electrons, usually two or more electrons, directly from a two-electron oxidant without going through such a tautomerization reaction are also included.

  The compound of type 3 is preferably represented by the general formula (D).

In the general formula (D), RED ₃ represents a reducing group that can be oxidized by one electron, Y ₃ represents a reactive group site that reacts after RED ₃ is oxidized by one electron, and specifically, a carbon-carbon double layer. It represents an organic group containing a binding site, a carbon-carbon triple bond site, an aromatic group site, or a non-aromatic heterocyclic group site of a benzo-fused ring. L ₃ represents a linking group that links RED ₃ and Y ₃ .

RED ₃ represents a group having the same meaning as RED _{12 in} formula (B), and preferably an arylamino group, a heterocyclic amino group, an aryloxy group, an arylthio group, an aryl group, an aromatic or non-aromatic heterocyclic group ( Particularly preferred is a nitrogen-containing heterocyclic group), more preferably an arylamino group, a heterocyclic amino group, an aryl group, or an aromatic or non-aromatic heterocyclic group, and among these heterocyclic groups, tetrahydroquinoline is preferred. Ring group, tetrahydroquinoxaline ring group, tetrahydroquinazoline ring group, indoline ring group, indole ring group, carbazole ring group, phenoxazine ring group, phenothiazine ring group, benzothiazoline ring group, pyrrole ring group, imidazole ring group, thiazole ring group , Benzimidazole ring group, benzimidazoline ring group, benzothiazoline ring group, 3 And 4-methylenedioxyphenyl-1-yl group are preferable.
RED ₃ is particularly preferably an arylamino group (particularly anilino group), an aryl group (particularly phenyl group), or an aromatic or non-aromatic heterocyclic group.

Here, when RED ₃ represents an aryl group, the aryl group preferably has at least one “electron-donating group”. The “electron donating group” is the same as described above.

When RED ₃ represents an aryl group, the substituent of the aryl group is more preferably an alkylamino group, a hydroxy group, an alkoxy group, a mercapto group, a sulfonamide group, an active methine group, or a non-aromatic nitrogen-containing group substituted with a nitrogen atom A heterocyclic group, more preferably an alkylamino group, a hydroxy group, an active methine group, and a non-aromatic nitrogen-containing heterocyclic group substituted with a nitrogen atom, most preferably an alkylamino group and a non-aromatic group substituted with a nitrogen atom Group nitrogen-containing heterocyclic group.

When the organic group (for example, vinyl group) containing a carbon-carbon double bond site represented by Y ₃ has a substituent, the substituent is preferably an alkyl group, phenyl group, acyl group, cyano group, alkoxycarbonyl. A group, a carbamoyl group, an electron donating group, etc., and an electron donating group is preferably an alkoxy group, a hydroxy group (which may be protected with a silyl group, for example, a trimethylsilyloxy group, a t-butyldimethylsilyloxy group). , Triphenylsilyloxy group, triethylsilyloxy group, phenyldimethylsilyloxy group, etc.), amino group, alkylamino group, arylamino group, sulfonamide group, active methine group, mercapto group, alkylthio group, and these It is a phenyl group having an electron donating group as a substituent.

Note here carbon - when the organic group having a hydroxy group as a substituent containing a carbon double bond moiety, Y ₃ is right partial _{structure:> C 1 = C 2 (} -OH) - but it will include this May be tautomerized to form the partial structure shown on the right:> C ₁ H—C ₂ (═O) —. Furthermore, in this case, it is also preferable that the substituent substituted on the C ₁ carbon is an electron withdrawing group. In this case, Y ₃ has a partial structure of “active methylene group” or “active methine group”. Become. The electron withdrawing group that can give such a partial structure of the active methylene group or active methine group is the same as that described in the description of the above-mentioned “active methine group”.

When the organic group (for example, ethynyl group) containing a carbon-carbon triple bond site represented by Y ₃ has a substituent, the substituent includes an alkyl group, a phenyl group, an alkoxycarbonyl group, a carbamoyl group, and an electron donating group. Etc. are preferable.

When Y ₃ represents an organic group containing an aromatic group, it is preferably an aryl group having an electron donating group as a substituent (particularly a phenyl group) or an indole ring group as an aromatic group, and an electron donating group here. The group is preferably a hydroxy group (which may be protected with a silyl group), an alkoxy group, an amino group, an alkylamino group, an active methine group, a sulfonamide group or a mercapto group.

When Y ₃ represents an organic group containing a non-aromatic heterocyclic group part of a benzo-fused ring, the non-aromatic heterocyclic group of the benzo-fused ring preferably contains an aniline structure as a partial structure, for example, an indoline ring Group, 1,2,3,4-tetrahydroquinoline ring group, 1,2,3,4-tetrahydroquinoxaline ring group, 4-quinolone ring group and the like.

The reactive group represented by Y ₃ is more preferably an organic group containing a carbon-carbon double bond site, an aromatic group site, or a benzo-fused non-aromatic heterocyclic group. More preferred are a carbon-carbon double bond site, a phenyl group having an electron donating group as a substituent, an indole ring group, and a benzo-fused non-aromatic heterocyclic group having an aniline structure as a partial structure. Here, the carbon-carbon double bond site preferably has at least one electron donating group as a substituent.

When the reactive group represented by Y ₃ has the same partial structure as the reducing group represented by RED ₃ as a result of selection from the range described so far, it is also represented by the general formula (D). Is a preferred example of the compound.

L ₃ represents a linking group that links RED ₃ and Y ₃ , specifically, a single bond, an alkylene group, an arylene group, a heterocyclic group, —O—, —S—, —NR _N —, —C (= O) -, - SO 2 -, - SO -, - it represents a single of the groups or a combination consisting of these groups, - P (= O). Here, _RN represents a hydrogen atom, an alkyl group, an aryl group, or a heterocyclic group. The linking group represented by L ₃ may have an arbitrary substituent. The linking group represented by L ₃ can be linked at any position of the groups represented by RED ₃ and Y ₃ in such a way as to substitute for any one hydrogen atom.
Preferred examples of L ₃ include a single bond, an alkylene group (particularly a methylene group, an ethylene group, a propylene group), an arylene group (particularly a phenylene group), a —C (═O) — group, an —O— group, —NH—. And a divalent linking group comprising a group, -N (alkyl group)-group, and a combination of these groups.

Group represented by L _3, a cation radical species RED ₃ generated by oxidation (X ⁺ ·), or from which a radical species generated with elimination of protons (X ·), tables in Y ₃ When a reactive group reacts to form a bond, it is preferable that an atomic group related to this can form a _3- to 7-membered cyclic structure including L ₃ . For this purpose, it is preferable that the radical species (X ^+. Or X.), the reactive group represented by Y, and L are connected by 3 to 7 atomic groups.

Next, the type 4 compound will be described.
A compound of type 4 is a compound having a ring structure substituted with a reducing group, and after the reducing group is oxidized by one electron, one or more electrons are emitted along with the ring structure cleavage reaction. Compound. The ring structure cleavage reaction referred to here means one having the following form.

  In the formula, compound a represents a type 4 compound. In compound a, D represents a reducing group, and X and Y represent atoms forming a bond that is cleaved after one-electron oxidation in the ring structure. First, the compound a is one-electron oxidized to produce a one-electron oxidant b. From this, the single bond of XX becomes a double bond, and at the same time, the bond of XY is cleaved to produce a ring-opened product c. Alternatively, a radical intermediate d may be generated from the one-electron oxidant b with proton desorption, and a ring-opening body e may be similarly generated therefrom. The compound of the present invention is characterized in that one or more electrons are subsequently released from the ring-opened product c or e thus produced.

  The ring structure possessed by the type 4 compound is a 3- to 7-membered carbocyclic or heterocyclic ring, and represents a monocyclic or condensed, saturated or unsaturated non-aromatic ring. A saturated ring structure is preferable, and a 3-membered ring or 4-membered ring is more preferable. Preferred examples of the ring structure include a cyclopropane ring, a cyclobutane ring, an oxirane ring, an oxetane ring, an aziridine ring, an azetidine ring, an episulfide ring, and a thietane ring. More preferred are cyclopropane ring, cyclobutane ring, oxirane ring, oxetane ring and azetidine ring, and particularly preferred are cyclopropane ring, cyclobutane ring and azetidine ring. The ring structure may have an arbitrary substituent.

  The compound of type 4 is preferably represented by the general formula (E) or (F).

In the general formula (E) and the general formula (F), RED ₄₁ and RED ₄₂ each represent a group having the same meaning as the RED _{12 in the} general formula (B), and the preferred ranges thereof are also the same. R _{40 to} R ₄₄ and R _{45 to} R ₄₉ each represent a hydrogen atom or a substituent. Z ₄₂ in formula (F) _{is, -CR 420 R 421 -, -} NR 423 -, or an -O-. Here, R ₄₂₀ and R ₄₂₁ each represent a hydrogen atom or a substituent, and R ₄₂₃ represents a hydrogen atom, an alkyl group, an aryl group or a heterocyclic group.

In general formula (E) and general formula (F), R ₄₀ and R ₄₅ preferably represent a hydrogen atom, an alkyl group, an aryl group, or a heterocyclic group, and more preferably a hydrogen atom, an alkyl group, or an aryl group. R _{41 to} R ₄₄ and R _{46 to} R ₄₉ are preferably a hydrogen atom, an alkyl group, an alkenyl group, an aryl group, a heterocyclic group, an arylthio group, an alkylthio group, an acylamino group, or a sulfonamide group, more preferably a hydrogen atom. , An alkyl group, an aryl group, and a heterocyclic group.

R _{41 to} R ₄₄ are preferably a case where at least one of them is a donor group and a case where R ₄₁ and R ₄₂ , or R ₄₃ and R ₄₄ are both electron withdrawing groups. More preferably, at least one of R _{41 to} R ₄₄ is a donor group. More preferably, at least one of R _{41 to} R ₄₄ is a donor group, and a group that is not a donor group among R _{41 to} R ₄₄ is a hydrogen atom or an alkyl group.

  The donor group mentioned here is an “electron-donating group” or an aryl group substituted with at least one “electron-donating group”. The donor group is preferably an alkylamino group, an arylamino group, a heterocyclic amino group, a 5-membered monocyclic or condensed ring electron-rich aromatic heterocyclic group containing at least one nitrogen atom in the ring, nitrogen A non-aromatic nitrogen-containing heterocyclic group substituted with an atom or a phenyl group substituted with at least one electron-donating group is used. More preferably, an alkylamino group, an arylamino group, a 5-membered monocyclic or condensed ring-excessive aromatic heterocyclic group containing at least one nitrogen atom in the ring (an indole ring, a pyrrole ring, a carbazole ring, etc.) ), A phenyl group substituted with an electron-donating group (such as a phenyl group substituted with three or more alkoxy groups, a phenyl group substituted with a hydroxy group, an alkylamino group, or an arylamino group). Particularly preferably, an arylamino group, a 5-membered monocyclic or condensed ring-containing electron-rich aromatic heterocyclic group (particularly a 3-indolyl group) or an electron-donating group containing at least one nitrogen atom in the ring is substituted. Used phenyl groups (particularly phenyl groups substituted with trialkoxyphenyl groups, alkylamino groups or arylamino groups).

Z ₄₂ is preferably —CR ₄₂₀ R ₄₂₁ — or —NR ₄₂₃ —, more preferably —NR ₄₂₃ —. R ₄₂₀ and R ₄₂₁ are preferably a hydrogen atom, an alkyl group, an aryl group, a heterocyclic group, an acylamino group, or a sulfoneamino group, and more preferably a hydrogen atom, an alkyl group, an aryl group, or a heterocyclic group. R ₄₂₃ preferably represents a hydrogen atom, an alkyl group, an aryl group or an aromatic heterocyclic group, more preferably a hydrogen atom, an alkyl group or an aryl group.

When each of R _{40 to} R ₄₉ and R ₄₂₀ , R ₄₂₁ and R ₄₂₃ is a substituent, the total number of carbon atoms is preferably 40 or less, more preferably 30 or less, and particularly preferably The total carbon number is 15 or less. In addition, these substituents may be bonded to each other or may be bonded to other sites in the molecule (RED ₄₁ , RED ₄₂ or Z ₄₂ ) to form a ring.

  In the compounds of types 1 to 4 of the present invention, the adsorptive group to silver halide is a group that directly adsorbs to silver halide or a group that promotes adsorption to silver halide. Specifically, mercapto A heterocyclic group containing at least one atom selected from a group (or a salt thereof), a thione group (—C (═S) —), a nitrogen atom, a sulfur atom, a selenium atom and a tellurium atom, a sulfide group, a cationic group, Or an ethynyl group. However, the type 2 compound of the present invention does not contain a sulfide group as an adsorptive group.

The mercapto group (or salt thereof) as the adsorptive group means the mercapto group (or salt thereof) itself, and more preferably a heterocyclic group or aryl group substituted with at least one mercapto group (or salt thereof). Or represents an alkyl group. Here, the heterocyclic group is a 5-membered to 7-membered monocyclic or condensed aromatic or non-aromatic heterocyclic group such as an imidazole ring group, a thiazole ring group, an oxazole ring group, or a benzimidazole ring group. , Benzthiazole ring group, benzoxazole ring group, triazole ring group, thiadiazole ring group, oxadiazole ring group, tetrazole ring group, purine ring group, pyridine ring group, quinoline ring group, isoquinoline ring group, pyrimidine ring group, triazine A cyclic group etc. are mentioned. Further, it may be a heterocyclic group containing a quaternized nitrogen atom. In this case, the substituted mercapto group may be dissociated into a meso ion. Examples of such a heterocyclic group include an imidazolium ring group, Examples include a pyrazolium ring group, a thiazolium ring group, a triazolium ring group, a tetrazolium ring group, a thiadiazolium ring group, a pyridinium ring group, a pyrimidinium ring group, and a triazinium ring group. Among them, a triazolium ring group (for example, 1,2,4- Triazolium-3-thiolate ring group) is preferable. Examples of the aryl group include a phenyl group and a naphthyl group. Examples of the alkyl group include linear, branched or cyclic alkyl groups having 1 to 30 carbon atoms. When the mercapto group forms a salt, the counter ion is a cation such as an alkali metal, alkaline earth metal or heavy metal (Li ⁺ , Na ⁺ , K ⁺ , Mg ²⁺ , Ag ⁺ , Zn ²⁺ etc.), ammonium ion Examples thereof include a heterocyclic group containing a quaternized nitrogen atom, a phosphonium ion, and the like.

  Further, the mercapto group as the adsorptive group may be tautomerized into a thione group, specifically, a thioamide group (here, —C (═S) —NH— group) and the thioamide group. A group having a partial structure of, ie, a chain or cyclic thioamide group, a thioureido group, a thiourethane group, or a dithiocarbamate group. Examples of cyclic groups include thiazolidine-2-thione group, oxazolidine-2-thione group, 2-thiohydantoin group, rhodanine group, isorhodanine group, thiobarbituric acid group, 2-thioxo-oxazolidine-4-one group Is mentioned.

  The thione group as an adsorptive group cannot be tautomerized to a mercapto group (including a hydrogen atom at the α-position of the thione group), including the case where the mercapto group described above is tautomerized into a thione group. A chain or cyclic thioamide group, thioureido group, thiourethane group, or dithiocarbamate group is also included.

  A heterocyclic group containing at least one atom selected from a nitrogen atom, a sulfur atom, a selenium atom and a tellurium atom as the adsorptive group is a -NH- group capable of forming imino silver (> NAg) and a partial structure of the heterocyclic ring A nitrogen-containing heterocyclic group, or a "-S-" group, a "-Se-" group, a "-Te-" group, or a "= N-" group that can coordinate to a silver ion through a coordination bond A heterocyclic group having a ring partial structure. Examples of the former include benzotriazole group, triazole group, indazole group, pyrazole group, tetrazole group, benzimidazole group, imidazole group, and purine group, and examples of the latter include thiophene. Group, thiazole group, oxazole group, benzothiazole group, benzoxazole group, thiadiazole group, oxadiazole group, triazine group, selenoa Lumpur group, benz seleno azole group, tellurium azole group, such as benz tellurium azole group. The former is preferred.

  The sulfide group as the adsorptive group includes all groups having a partial structure of “—S—”, preferably alkyl (or alkylene) -S-alkyl (or alkylene), aryl (or arylene) -S—. A group having a partial structure of alkyl (or alkylene), aryl (or arylene) -S-aryl (or arylene). Furthermore, these sulfide groups may form a cyclic structure or may be an -S-S- group. Specific examples in the case of forming a cyclic structure include a thiolane ring, a 1,3-dithiolane ring or a 1,2-dithiolane ring, a thiane ring, a dithiane ring, a tetrahydro-1,4-thiazine ring (thiomorpholine ring) and the like. Groups. Particularly preferred as the sulfide group is a group having a partial structure of alkyl (or alkylene) -S-alkyl (or alkylene).

  The cationic group as the adsorptive group means a group containing a quaternized nitrogen atom, specifically, an ammonio group or a group containing a nitrogen-containing heterocyclic group containing a quaternized nitrogen atom. . However, the cationic group does not become a part of an atomic group forming a dye structure (for example, a cyanine chromophore). Here, the ammonio group is a trialkylammonio group, a dialkylarylammonio group, an alkyldiarylammonio group or the like, and examples thereof include a benzyldimethylammonio group, a trihexylammonio group, and a phenyldiethylammonio group. Examples of the nitrogen-containing heterocyclic group containing a quaternized nitrogen atom include a pyridinio group, a quinolinio group, an isoquinolinio group, an imidazolio group, and the like. A pyridinio group and an imidazolio group are preferable, and a pyridinio group is particularly preferable. These nitrogen-containing heterocyclic groups containing a quaternized nitrogen atom may have an arbitrary substituent, but in the case of a pyridinio group and an imidazolio group, the substituent is preferably an alkyl group, an aryl group, an acylamino group , A chloro atom, an alkoxycarbonyl group, a carbamoyl group, and the like. In the case of a pyridinio group, a phenyl group is particularly preferable as a substituent.

An ethynyl group as an adsorptive group means a —C≡CH group, and a hydrogen atom may be substituted.
The adsorptive group may have an arbitrary substituent.

  Specific examples of the adsorptive group further include those described in pages 4 to 7 of JP-A No. 11-95355.

  In the present invention, preferred adsorptive groups are mercapto-substituted nitrogen-containing heterocyclic groups (for example, 2-mercaptothiadiazole group, 3-mercapto-1,2,4-triazole group, 5-mercaptotetrazole group, 2-mercapto-1). , 3,4-oxadiazole group, 2-mercaptobenzoxazole group, 2-mercaptobenzthiazole group, 1,5-dimethyl-1,2,4-triazolium-3-thiolate group), or imino silver (> A nitrogen-containing heterocyclic group (for example, a benzotriazole group, a benzimidazole group, an indazole group, etc.) having a —NH— group that can form NAg) as a partial structure of the heterocyclic ring. Particularly preferred are 5-mercaptotetrazole group, 3-mercapto-1,2,4-triazole group, and benzotriazole group, most preferred are 3-mercapto-1,2,4-triazole group, and 5 -Mercaptotetrazole group.

  Among the compounds of the present invention, compounds having two or more mercapto groups in the molecule as partial structures are also particularly preferred compounds. Here, the mercapto group (—SH) may be a thione group if it can be tautomerized. Examples of such compounds include adsorbable groups having a partial structure of a mercapto group or thione group described above (for example, a ring-forming thioamide group, an alkyl mercapto group, an aryl mercapto group, a heterocyclic mercapto group, etc.) Or a compound having two or more mercapto groups or thione groups as a partial structure (for example, a dimercapto-substituted nitrogen-containing heterocyclic group). You may have one or more.

  Examples of the adsorptive group having two or more mercapto groups as a partial structure (such as a dimercapto-substituted nitrogen-containing heterocyclic group) include 2,4-dimercaptopyrimidine group, 2,4-dimercaptotriazine group, 3, 5-dimercapto-1,2,4-triazole group, 2,5-dimercapto-1,3-thiazole group, 2,5-dimercapto-1,3-oxazole group, 2,7-dimercapto-5-methyl-s -Triazolo (1,5-A) -pyrimidine, 2,6,8-trimercaptopurine, 6,8-dimercaptopurine, 3,5,7-trimercapto-s-triazolotriazine, 4,6-di And mercaptopyrazolopyrimidine, 2,5-dimercaptoimidazole, etc., 2,4-dimercaptopyrimidine group, 2,4-dimercaptotriazine group, 3, - dimercapto-1,2,4-triazole group are particularly preferred.

The adsorptive group may be substituted anywhere in the general formulas (A) to (F) and the general formulas (1) to (3). In the general formulas (A) to (D), RED ₁₁ , RED ₁₂ , RED ₂ and RED ₃ are represented by RED ₄₁ , R ₄₁ , RED ₄₂ and R _{46 to} R ₄₈ in the general formulas (E) and (F), and R ₁ and R ₂ in the general formulas (1) to (3). , R ₁₁ , R ₁₂ , R ₃₁ , L ₁ , L ₂₁ , and L ₃₁ are preferably substituted at any position, and in all of the general formulas (A) to (F), RED _{11 to} RED ₄₂ are substituted. More preferably it is substituted.

The partial structure of the spectral sensitizing dye is a group containing a chromophore of the spectral sensitizing dye, and is a residue obtained by removing any hydrogen atom or substituent from the spectral sensitizing dye compound. The partial structure of the spectral sensitizing dye may be substituted anywhere in the general formulas (A) to (F) and the general formulas (1) to (3), but in the general formulas (A) to (D), RED ₁₁ , RED ₁₂ , RED ₂ , RED ₃ , RED ₄₁ , R ₄₁ , RED ₄₂ , R _{46 to} R ₄₈ in general formulas (E) and (F), and R in general formulas (1) to (3) ₁ , R ₂ , R ₁₁ , R ₁₂ , R ₃₁ , L ₁ , L ₂₁ , and L ₃₁ are preferably substituted at any position except RED _{11 in} all of the general formulas (A) to (F). it is more preferably substituted in ~RED _42. Preferred spectral sensitizing dyes are spectral sensitizing dyes typically used in color sensitization techniques such as cyanine dyes, complex cyanine dyes, merocyanine dyes, complex merocyanine dyes, homopolar cyanine dyes, Includes styryl dyes and hemicyanine dyes. Exemplary spectral sensitizing dyes are disclosed in Research Disclosure, Item 36544, September 1994. Research Disclosure or F.I. M.M. One of ordinary skill in the art can synthesize these dyes by the procedure described in Hammer's The Cyanines and Related Compounds (Interscience Publishers, New yprk, 1964). Further, all the dyes described in JP-A-11-95355 (US Pat. No. 6,054,260), pages 7 to 14 are applied as they are.

  The compounds of types 1 to 4 of the present invention preferably have a total carbon number of 10 to 60. More preferably, it is 15-50, More preferably, it is 18-40, Most preferably, it is 18-30.

  The compounds of types 1 to 4 of the present invention are subjected to 1-electron oxidation triggered by exposure of the silver halide photographic light-sensitive material using the compound, and after the subsequent reaction, further 1 electron, or 2 electrons or more depending on the type. Electrons are emitted and oxidized, and the oxidation potential of the first electron is preferably about 1.4 V or less, and more preferably 1.0 V or less. This oxidation potential is preferably higher than 0V, more preferably higher than 0.3V. Accordingly, the oxidation potential is preferably in the range of about 0V to about 1.4V, more preferably about 0.3V to about 1.0V.

  Here, the oxidation potential can be measured by a cyclic voltammetry technique. Specifically, a sample is dissolved in a solution of acetonitrile: water (including 0.1 M lithium perchlorate) = 80%: 20% (volume%). After bubbling nitrogen gas for 10 minutes, a glassy carbon disk was used as the working electrode, a platinum wire was used as the counter electrode, and a calomel electrode (SCE) was used as the reference electrode at 25 ° C. and 0.1 V / Measured at a potential scanning speed of seconds. The oxidation potential versus SCE is taken at the peak potential of the cyclic voltammetry wave.

  In the case where the compounds of types 1 to 4 of the present invention are one-electron oxidized and further emit one electron after the subsequent reaction, the subsequent oxidation potential is preferably −0.5 V to −2 V. More preferably, it is -0.7V--2V, More preferably, it is -0.9V--1.6V.

  In the case where the compound of types 1 to 4 of the present invention is a compound that is oxidized by one electron and emits two or more electrons after the subsequent reaction and is oxidized, there is no particular limitation on the oxidation potential of this latter stage. Absent. This is because the oxidation potential of the second electron and the oxidation potential of the third and subsequent electrons cannot be clearly distinguished, and it is often difficult to accurately measure and distinguish these actually.

Next, the compound of type 5 will be described.
A compound of type 5 is represented by XY, where X represents a reducing group, Y represents a leaving group, and a one-electron oxidant produced by one-electron oxidation of the reducing group represented by X is This is a compound capable of releasing X by further elimination of Y with subsequent XY bond cleavage reaction to generate an X radical, from which another electron is emitted. The reaction when such a type 5 compound is oxidized can be represented by the following formula.

  The compound of type 5 preferably has an oxidation potential of 0V to 1.4V, more preferably 0.3V to 1.0V. The oxidation potential of the radical X · generated in the above reaction formula is preferably −0.7 V to −2.0 V, more preferably −0.9 V to −1.6 V.

  The compound of type 5 is preferably represented by the general formula (G).

In General Formula (G), RED ₀ represents a reducing group, L ₀ represents a leaving group, and R ₀ and R ₀₀ represent a hydrogen atom or a substituent. RED ₀ and R ₀ , and R ₀ and R ₀₀ may be bonded to each other to form a ring structure. RED ₀ represents a group having the same meaning as RED _{2 in} formula (C), and its preferred range is also the same. R ₀ and R ₀₀ are groups having the same meanings as R ₂₁ and R _{22 in} formula (C), and their preferred ranges are also the same. However, R ₀ and R ₀₀ do not represent the same group as L ₀ except for a hydrogen atom. RED ₀ and R ₀ may be bonded to each other to form a ring structure. As an example of the ring structure, RED ₂ and R _{21 in} formula (C) are linked to form a ring structure. The same example as the case is mentioned, The preferable range is also the same. Examples of the ring structure formed by combining R ₀ and R ₀₀ with each other include a cyclopentane ring and a tetrahydrofuran ring. In the general formula (G), L ₀ is a group having the same meaning as L _{2 in the} general formula (C), and the preferred range thereof is also the same.

The compound represented by the general formula (G) preferably has an adsorbing group for silver halide or a partial structure of a spectral sensitizing dye in the molecule, but L ₀ is a group other than a silyl group. When expressed, it does not have two or more adsorptive groups in the molecule at the same time. However, here, the sulfide group as the adsorptive group does not depend on L ₀ and may have two or more thereof.

Examples of the adsorptive group to the silver halide of the compound represented by the general formula (G) include the same adsorptive groups that the compounds of types 1 to 4 of the present invention may have. In addition, all those described as “silver halide adsorbing groups” on pages 4 to 7 of JP-A No. 11-95355 can be mentioned, and preferred ranges are also the same.
The partial structure of the spectral sensitizing dye that the compound represented by the general formula (G) may have is the partial structure of the spectral sensitizing dye that the compounds of types 1 to 4 of the present invention may have. However, at the same time, all those described as “light-absorbing groups” on pages 7 to 14 of JP-A No. 11-95355 can be mentioned, and preferred ranges are also the same.

  Specific examples of the compounds of types 1 to 5 of the present invention are listed below, but the present invention is not limited thereto.

  The compounds of types 1 to 4 of the present invention are described in detail in Japanese Patent Application No. 2002-192373, Japanese Patent Application No. 2002-188537, Japanese Patent Application No. 2002-188536, Japanese Patent Application No. 2001-272137, and Japanese Patent Application No. 2002-192374, respectively. Same as described compound. Specific compound examples described in these patent application specifications can also be given as specific examples of the compounds of types 1 to 4 of the present invention. The synthesis examples of the compounds of types 1 to 4 of the present invention are also the same as those described in these patents.

  Specific examples of the compound of type 5 of the present invention are further described in JP-A-9-211769 (compounds PMT-1 to S-37 described in Table E and Table F on pages 28-32), JP-A-9-21774. JP-A-11-95355 (compounds INV1-36), JP-T-2001-99696 (compounds 1-74, 80-87, 92-122), US Pat. No. 5,747,235, US Pat. No. 5,747, No. 236, European Patent No. 786692A1 (compounds INV1 to 35), European Patent No. 893732A1, US Pat. No. 6,054,260, US Pat. No. 5,994,051, etc. Examples of compounds referred to as “deprotonated electron donating sensitizers” are mentioned as they are.

  The compounds of types 1 to 5 of the present invention may be used at any time during the process of producing a photothermographic material when preparing a photosensitive silver halide emulsion. For example, at the time of photosensitive silver halide grain formation, desalting step, chemical sensitization, before coating. Moreover, it can also add in several steps in these processes. The addition position is preferably from the end of formation of the photosensitive silver halide grains to before the desalting step, at the time of chemical sensitization (immediately after the start of chemical sensitization to immediately after completion), and before coating, more preferably from the time of chemical sensitization Until before mixing with the non-photosensitive organic silver salt.

  The compounds of types 1 to 5 of the present invention are preferably added after being dissolved in water, a water-soluble solvent such as methanol or ethanol, or a mixed solvent thereof. When the compound is dissolved in water, the compound having higher solubility when the pH is increased or decreased may be dissolved at a higher or lower pH and added.

The compounds of types 1 to 5 of the present invention are preferably used in emulsion layers containing photosensitive silver halide and non-photosensitive organic silver salt, but contain photosensitive silver halide and non-photosensitive organic silver salt. It may be added to the protective layer or intermediate layer together with the emulsion layer to be diffused during coating. The timing of addition of the compound of the present invention is preferably before or after the sensitizing dye, and is preferably 1 × 10 ^{−9 to} 5 × 10 ⁻¹ mol, more preferably 1 × 10 ^{−8 to} 5 per mol of silver halide. X10 ^-2 mol in a silver halide emulsion layer.

10) Two or more silver halides in combination The photosensitive silver halide emulsion in the light-sensitive material used in the present invention may be one kind or two or more kinds (for example, those having different average grain sizes, those having different halogen compositions, Those having different crystal habits and different chemical sensitization conditions may be used in combination. The gradation can be adjusted by using a plurality of types of photosensitive silver halides having different sensitivities. Examples of these technologies include JP-A-57-119341, 53-106125, 47-3929, 48-55730, 46-5187, 50-73627, 57-150841 and the like. Can be mentioned. The sensitivity difference is preferably 0.2 log E or more for each emulsion.

11) Coating Amount The addition amount of the photosensitive silver halide is preferably indicated by the amount of coated silver per photosensitive material 1 m ^2, is ^{0.03g / m 2 ~0.6g / m 2} , 0.05g / further preferably m ² ~0.4g / m ^2, and most preferably from ^{0.07g / m 2 ~0.3g / m 2} , relative to the organic silver salt to 1 mole, photosensitive halide Silver is preferably 0.01 mol or more and 0.5 mol or less, more preferably 0.02 mol or more and 0.3 mol or less, and further preferably 0.03 mol or more and 0.2 mol or less.

12) Mixing of photosensitive silver halide and organic silver salt Regarding the mixing method and mixing conditions of separately prepared photosensitive silver halide and organic silver salt, the prepared silver halide grains and organic silver salt were stirred at high speed, respectively. Prepare an organic silver salt by mixing with a machine, ball mill, sand mill, colloid mill, vibration mill, homogenizer, etc., or by mixing photosensitive silver halide that has been prepared at any time during the preparation of the organic silver salt However, there is no particular limitation as long as the effects of the present invention are sufficiently exhibited. Moreover, mixing two or more organic silver salt aqueous dispersions and two or more photosensitive silver salt aqueous dispersions when mixing is a preferred method for adjusting photographic characteristics.

13) Mixing the silver halide into the coating solution The preferred addition time of the silver halide of the present invention to the image forming layer coating solution is from 180 minutes before application, preferably from 60 minutes to 10 seconds before application. However, the mixing method and mixing conditions are not particularly limited as long as the effects of the present invention are sufficiently exhibited. Specific mixing methods include mixing in a tank in which the average residence time calculated from the addition flow rate and the amount of liquid fed to the coater is a desired time, and N.I. Harnby, M.M. F. Edwards, A.D. W. There is a method using a static mixer described in Chapter 8 of Nienow's Koji Takahashi "Liquid Mixing Technology" (published by Nikkan Kogyo Shimbun, 1989).

(Description of binder)
Any polymer may be used as the binder of the organic silver salt-containing layer of the present invention, and suitable binders are transparent or translucent and generally colorless, natural resins and polymers and copolymers, synthetic resins and polymers and copolymers, etc. Film forming media such as gelatins, rubbers, poly (vinyl alcohol) s, hydroxyethyl celluloses, cellulose acetates, cellulose acetate butyrates, poly (vinyl pyrrolidone) s, casein, starch, poly (acrylic acid) ), Poly (methyl methacrylic acid), poly (vinyl chloride), poly (methacrylic acid), styrene-maleic anhydride copolymers, styrene-acrylonitrile copolymers, styrene-butadiene copolymers , Poly (vinyl acetal) s (eg, poly (vinyl Lumar) and poly (vinyl butyral)), poly (esters), poly (urethane) s, phenoxy resins, poly (vinylidene chloride) s, poly (epoxides), poly (carbonates), poly (vinyl acetate) s , Poly (olefin) s, cellulose esters, and poly (amides). The binder may be coated from water or an organic solvent or emulsion.

  In the present invention, the glass transition temperature of the binder that can be used in combination with the layer containing the organic silver salt is preferably 0 ° C. or higher and 80 ° C. or lower (hereinafter sometimes referred to as a high Tg binder), and preferably 10 ° C. to 70 ° C. Is more preferable, and it is still more preferable that it is 15 to 60 degreeC.

In this specification, Tg was calculated by the following formula.
1 / Tg = Σ (Xi / Tgi)
Here, it is assumed that n monomer components from i = 1 to n are copolymerized in the polymer. Xi is the weight fraction of the i-th monomer (ΣXi = 1), and Tgi is the glass transition temperature (absolute temperature) of the homopolymer of the i-th monomer. However, Σ is the sum from i = 1 to n. The homopolymer glass transition temperature (Tgi) of each monomer was the value of Polymer Handbook (3rd Edition) (by J. Brandrup, EH Immergut (Wiley-Interscience, 1989)).

  Two or more binders may be used in combination as required. Further, a glass transition temperature of 20 ° C. or higher and a glass transition temperature of less than 20 ° C. may be used in combination. When two or more kinds of polymers having different Tg are blended, the weight average Tg is preferably within the above range.

In the present invention, the organic silver salt-containing layer is preferably applied and dried using a coating solution in which 30% by mass or more of the solvent is water to form a film.
In the present invention, when the organic silver salt-containing layer is formed using a coating solution in which 30% by mass or more of the solvent is water and dried, the binder of the organic silver salt-containing layer is further added to an aqueous solvent ( When it is soluble or dispersible in an aqueous solvent), the performance is improved particularly when it is made of a latex of a polymer having an equilibrium water content of 2% by mass or less at 25 ° C. and 60% RH. The most preferable form is one prepared so that the ionic conductivity is 2.5 mS / cm or less, and as such a preparation method, there is a method of performing purification treatment using a separation functional membrane after polymer synthesis.

  The aqueous solvent in which the polymer is soluble or dispersible here is a mixture of water or water and 70% by mass or less of a water-miscible organic solvent. Examples of the water-miscible organic solvent include alcohols such as methyl alcohol, ethyl alcohol, and propyl alcohol, cellosolvs such as methyl cellosolve, ethyl cellosolve, and butyl cellosolve, ethyl acetate, and dimethylformamide.

  In the case of a system in which the polymer is not dissolved thermodynamically and exists in a so-called dispersed state, the term aqueous solvent is used here.

The “equilibrium moisture content at 25 ° C. and 60% RH” is the following using the weight W1 of the polymer in the humidity-controlled equilibrium under the atmosphere of 25 ° C. and 60% RH and the weight W0 of the polymer in the absolutely dry state at 25 ° C. It can be expressed as
Equilibrium water content at 25 ° C. and 60% RH = [(W1-W0) / W0] × 100 (mass%)

  For the definition and measurement method of moisture content, for example, Polymer Engineering Course 14, Polymer Material Testing Method (Edited by Society of Polymer Sciences, Jinshokan) can be referred to.

  The equilibrium moisture content at 25 ° C. and 60% RH of the binder polymer of the present invention is preferably 2% by mass or less, more preferably 0.01% by mass or more and 1.5% by mass or less, and further preferably 0.02% by mass. % To 1% by mass is desirable.

  In the present invention, a polymer dispersible in an aqueous solvent is particularly preferred. Examples of the dispersed state may be either latex in which fine particles of a water-insoluble hydrophobic polymer are dispersed or polymer molecules dispersed in a molecular state or a micelle form. preferable. The average particle size of the dispersed particles is 1 to 50000 nm, preferably 5 to 1000 nm, more preferably 10 to 500 nm, and still more preferably 50 to 200 nm. The particle size distribution of the dispersed particles is not particularly limited, and may have a wide particle size distribution or a monodispersed particle size distribution. Mixing two or more types having a monodispersed particle size distribution is also a preferable method for controlling the physical properties of the coating solution.

  In the present invention, preferred embodiments of the polymer that can be dispersed in an aqueous solvent include acrylic polymers, poly (esters), rubbers (eg, SBR resin), poly (urethanes), poly (vinyl chloride) s, poly (acetic acid). Hydrophobic polymers such as vinyl), poly (vinylidene chloride) and poly (olefin) can be preferably used. These polymers may be linear polymers, branched polymers, crosslinked polymers, so-called homopolymers obtained by polymerizing a single monomer, or copolymers obtained by polymerizing two or more types of monomers. In the case of a copolymer, it may be a random copolymer or a block copolymer. These polymers have a number average molecular weight of 5,000 to 1,000,000, preferably 10,000 to 200,000. When the molecular weight is too small, the mechanical strength of the image forming layer is insufficient, and when the molecular weight is too large, the film formability is poor, which is not preferable. A crosslinkable polymer latex is particularly preferably used.

(Specific examples of latex)
Specific examples of preferable polymer latex include the following. Below, it represents using a raw material monomer, the numerical value in a parenthesis is the mass%, and molecular weight is a number average molecular weight. When a polyfunctional monomer was used, the concept of molecular weight was not applicable because a crosslinked structure was formed, so it was described as crosslinkability, and the description of molecular weight was omitted. Tg represents the glass transition temperature.

Latex of P-1; -MMA (70) -EA (27) -MAA (3)-(molecular weight 37000, Tg 61 ° C.)
Latex of P-2; -MMA (70) -2EHA (20) -St (5) -AA (5)-(molecular weight 40000, Tg 59 ° C.)
P-3; latex of -St (50) -Bu (47) -MAA (3)-(crosslinkability, Tg-17 ° C)
Latex of P-4; -St (68) -Bu (29) -AA (3)-(crosslinkability, Tg 17 ° C.)
Latex of P-5; -St (71) -Bu (26) -AA (3)-(crosslinkability, Tg 24 ° C.)
Latex of P-6; -St (70) -Bu (27) -IA (3)-(crosslinkability)
Latex of P-7; -St (75) -Bu (24) -AA (1)-(crosslinkability, Tg 29 ° C.)
P-8; Latex (crosslinkable) of -St (60) -Bu (35) -DVB (3) -MAA (2)-
Latex (crosslinkability) of P-9; -St (70) -Bu (25) -DVB (2) -AA (3)-
P-10; latex of VC (50) -MMA (20) -EA (20) -AN (5) -AA (5)-(molecular weight 80000)
P-11; latex of VDC (85) -MMA (5) -EA (5) -MAA (5)-(molecular weight 67000)
Latex of P-12; -Et (90) -MAA (10)-(molecular weight 12000)
P-13; Latex of -St (70) -2EHA (27) -AA (3) (molecular weight 130000, Tg 43 ° C)
P-14; latex of MMA (63) -EA (35) -AA (2) (molecular weight 33,000, Tg 47 ° C.)
Latex of P-15; -St (70.5) -Bu (26.5) -AA (3)-(crosslinkability, Tg 23 ° C.)
Latex of P-16; -St (69.5) -Bu (27.5) -AA (3)-(crosslinkability, Tg 20.5 ° C)

  The abbreviations for the above structures represent the following monomers. MMA; methyl methacrylate, EA; ethyl acrylate, MAA; methacrylic acid, 2EHA; 2-ethylhexyl acrylate, St; styrene, Bu; butadiene, AA; acrylic acid, DVB; divinylbenzene, VC; vinyl chloride, AN; Vinylidene chloride, Et; ethylene, IA; itaconic acid.

  The polymer latex described above is also commercially available, and the following polymers can be used. Examples of the acrylic polymer include Sebian A-4635, 4718, 4601 (manufactured by Daicel Chemical Industries, Ltd.), Nipol Lx811, 814, 821, 820, 857 (manufactured by Nippon Zeon Co., Ltd.), poly ( Examples of esters) include, for example, poly (urethanes) such as FINITEX ES650, 611, 675, 850 (above Dainippon Ink and Chemicals), WD-size, WMS (Eastman Chemical). Examples of rubbers such as HYDRAN AP10, 20, 30, 40 (above made by Dainippon Ink Chemical Co., Ltd.) include LACSTAR 7310K, 3307B, 4700H, 7132C (made by Dainippon Ink Chemical Co., Ltd.) , Nipol Lx416, 410, 438C, 2507 (all manufactured by Nippon Zeon Co., Ltd.) However, examples of poly (vinyl chloride) include G351 and G576 (manufactured by Nippon Zeon Co., Ltd.), and examples of poly (vinylidene chloride) include L502 and L513 (manufactured by Asahi Kasei Kogyo Co., Ltd.). Examples of poly (olefin) s include Chemipearl S120, SA100 (manufactured by Mitsui Petrochemical Co., Ltd.).

  These polymer latexes may be used alone or in combination of two or more as required.

(Preferred latex)
As the polymer latex used in the present invention, a styrene-butadiene copolymer latex is particularly preferable. The weight ratio of the styrene monomer unit to the butadiene monomer unit in the styrene-butadiene copolymer is preferably 40:60 to 95: 5. The proportion of the styrene monomer unit and the butadiene monomer unit in the copolymer is preferably 60 to 99% by mass.
Moreover, it is preferable that the polymer latex of this invention contains 1-6 mass% of acrylic acid or methacrylic acid with respect to the sum of styrene and butadiene, More preferably, it contains 2-5 mass%. The polymer latex of the present invention preferably contains acrylic acid. The preferred molecular weight range is the same as described above.

  Examples of latexes of styrene-butadiene acid copolymer that are preferably used in the present invention include the aforementioned P-3 to P-8,15, commercially available LACSTAR-3307B, 7132C, Nipol Lx416, and the like.

  If necessary, a hydrophilic polymer such as gelatin, polyvinyl alcohol, methylcellulose, hydroxypropylcellulose, carboxymethylcellulose may be added to the organic silver salt-containing layer of the light-sensitive material of the present invention. The amount of these hydrophilic polymers added is preferably 30% by mass or less, more preferably 20% by mass or less, based on the total binder of the organic silver salt-containing layer.

  The organic silver salt-containing layer (that is, the image forming layer) of the present invention is preferably formed using a polymer latex. The amount of binder in the organic silver salt-containing layer is such that the weight ratio of total binder / organic silver salt is 1/10 to 10/1, more preferably 1/3 to 5/1, and still more preferably 1/1 to 3/1. / 1 range.

  In addition, such an organic silver salt-containing layer is usually a photosensitive layer (emulsion layer) containing a photosensitive silver halide which is a photosensitive silver salt. The weight ratio of silver is 400-5, more preferably 200-10.

The total binder amount of the image forming layer of the present invention is preferably 0.2 g / m ^{2 to} 30 g / m ² , more preferably 1 g / m ^{2 to} 15 g / m ² , and still more preferably 2 g / m ^{2 to} 10 g / m ^2. Range. The image forming layer of the present invention may contain a crosslinking agent for crosslinking, a surfactant for improving coating properties, and the like.
(Preferable solvent for coating solution)

  In the present invention, the solvent of the organic silver salt-containing layer coating solution of the light-sensitive material (here, for simplicity, the solvent and the dispersion medium are collectively referred to as a solvent) is preferably an aqueous solvent containing 30% by mass or more of water. As a component other than water, any water-miscible organic solvent such as methyl alcohol, ethyl alcohol, isopropyl alcohol, methyl cellosolve, ethyl cellosolve, dimethylformamide, and ethyl acetate may be used. The water content of the solvent of the coating solution is preferably 50% by mass or more, more preferably 70% by mass or more. Examples of preferred solvent compositions include water, water / methyl alcohol = 90/10, water / methyl alcohol = 70/30, water / methyl alcohol / dimethylformamide = 80/15/5, water / methyl alcohol / Ethyl cellosolve = 85/10/5, water / methyl alcohol / isopropyl alcohol = 85/10/5, etc. (numerical values are mass%).

(Description of antifogging agent)
Antifoggants, stabilizers and stabilizer precursors which can be used in the present invention are disclosed in paragraph No. 0070 of JP-A No. 10-62899, page 20, line 57 to page 21, line 7 of European Patent Publication No. 0803764A1. Compounds described in JP-A-9-281737 and JP-A-9-329864, compounds described in US Pat. Nos. 6,083,681, 6,083,681, and European Patent 1048875 It is done.
The antifoggant preferably used in the present invention is an organic halide, and examples thereof include those disclosed in the patents described in paragraph Nos. 0111 to 0112 of JP-A No. 11-65021. In particular, an organic halogen compound represented by formula (P) in JP-A No. 2000-284399, an organic polyhalogen compound represented by formula (II) in JP-A No. 10-339934, JP-A No. 2001-31644 and JP-A No. 2001-31644 are disclosed. The organic polyhalogen compounds described in 2001-33911 are preferred.

1) Polyhalogen Compound Hereinafter, preferred organic polyhalogen compounds in the present invention will be described in detail.
A preferred polyhalogen compound of the present invention is a compound represented by the following general formula (H).
General formula (H)
Q- (Y) n-C (Z ₁ ) (Z ₂ ) X
In the general formula (H), Q represents an alkyl group, an aryl group or a heterocyclic group, Y represents a divalent linking group, n represents 0 or 1, Z ₁ and Z ₂ represent a halogen atom, X represents a hydrogen atom or an electron withdrawing group.
In general formula (H), Q is preferably an aryl group or a heterocyclic group.
In the general formula (H), when Q is a heterocyclic group, a nitrogen-containing heterocyclic group containing 1 to 2 nitrogen atoms is preferable, and a 2-pyridyl group and a 2-quinolyl group are particularly preferable.
In the general formula (H), when Q is an aryl group, Q preferably represents a phenyl group substituted with an electron-attracting group having a positive Hammett's substituent constant σp. For Hammett's substituent constants, see Journal of Medicinal Chemistry, 1973, Vol. 16, no. 11, 1207-1216 etc. can be referred to. Examples of such an electron withdrawing group include a halogen atom (fluorine atom (σp value: 0.06), chlorine atom (σp value: 0.23), bromine atom (σp value: 0.23), iodine atom. (Σp value: 0.18)), trihalomethyl group (tribromomethyl (σp value: 0.29), trichloromethyl (σp value: 0.33), trifluoromethyl (σp value: 0.54)), Cyano group (σp value: 0.66), nitro group (σp value: 0.78), aliphatic aryl, or heterocyclic sulfonyl group (for example, methanesulfonyl (σp value: 0.72)), aliphatic aryl Or a heterocyclic acyl group (for example, acetyl (σp value: 0.50), benzoyl (σp value: 0.43)), alkynyl group (for example, C≡CH (σp value: 0.23)), aliphatic Aryl or heterocyclic oxycarbo Group (for example, methoxycarbonyl (σp value: 0.45), phenoxycarbonyl (σp value: 0.44)), carbamoyl group (σp value: 0.36), sulfamoyl group (σp value: 0.57), Examples thereof include a sulfoxide group, a heterocyclic group, and a phosphoryl group. The σp value is preferably in the range of 0.2 to 2.0, more preferably in the range of 0.4 to 1.0. Particularly preferred as the electron withdrawing group is a carbamoyl group, an alkoxycarbonyl group, an alkylsulfonyl group or an alkylphosphoryl group, and among them, a carbamoyl group is most preferred.
X is preferably an electron-withdrawing group, more preferably a halogen atom, aliphatic / aryl or heterocyclic sulfonyl group, aliphatic / aryl or heterocyclic acyl group, aliphatic / aryl or heterocyclic oxycarbonyl group, A carbamoyl group and a sulfamoyl group, particularly preferably a halogen atom. Among the halogen atoms, a chlorine atom, a bromine atom and an iodine atom are preferable, a chlorine atom and a bromine atom are more preferable, and a bromine atom is particularly preferable.
Y preferably represents —C (═O) —, —SO— or —SO ₂ —, more preferably —C (═O) — or —SO ₂ —, and particularly preferably —SO ₂ —. . n represents 0 or 1, and is preferably 1.

  Specific examples of the compound of the general formula (H) of the present invention are shown below.

Other preferred polyhalogen compounds of the present invention include compounds described in JP-A Nos. 2001-31644, 2001-56526, and 2001-209145.
The compound represented by the general formula (H) of the present invention is preferably used in the range of 10 ⁻⁴ to 1 mol, more preferably 10 ^{−3 to} 0 per mol of the non-photosensitive silver salt of the image forming layer. It is preferably used in the range of 0.5 mol, more preferably in the range of 1 × 10 ^{-2 to} 0.2 mol.
In the present invention, the antifoggant is added to the light-sensitive material by the method described in the method for containing a reducing agent, and the organic polyhalogen compound is also preferably added as a solid fine particle dispersion.

2) Other antifoggants Other antifoggants include mercury (II) salts described in paragraph No. 0113 of JP-A No. 11-65021, benzoic acids described in paragraph No. 0114 of the same, salicylic acid derivatives disclosed in JP-A No. 2000-206642, A formalin scavenger compound represented by the formula (S) in JP-A-2000-221634, a triazine compound according to claim 9 in JP-A-11-352624, and a compound represented by the general formula (III) in JP-A-6-11791 4-hydroxy-6-methyl-1,3,3a, 7-tetrazaindene and the like.

The photothermographic material in the invention may contain an azolium salt for the purpose of fog prevention. Examples of the azolium salt include compounds represented by general formula (XI) described in JP-A-59-193447, compounds described in JP-B-55-12581, and general formula (II) described in JP-A-60-153039. And the compounds represented. The azolium salt may be added to any part of the photosensitive material, but the addition layer is preferably added to the layer having the photosensitive layer, and more preferably to the organic silver salt-containing layer. The azolium salt may be added at any step in the coating solution preparation. When added to the organic silver salt-containing layer, any step from the preparation of the organic silver salt to the preparation of the coating solution may be used. To immediately before coating. The azolium salt may be added by any method such as powder, solution, fine particle dispersion.
Moreover, you may add as a solution mixed with other additives, such as a sensitizing dye, a reducing agent, and a color toning agent.
In the present invention, the azolium salt may be added in any amount, but it is preferably 1 × 10 ⁻⁶ mol or more and 2 mol or less, more preferably 1 × 10 ⁻³ mol or more and 0.5 mol or less per 1 mol of silver.

(Other additives)
1) Mercapto, disulfide, and thiones In the present invention, mercapto compounds and disulfide compounds are used to control development by suppressing or accelerating development, to improve spectral sensitization efficiency, and to improve storage stability before and after development. And thione compounds, paragraphs 0067 to 0069 of JP-A-10-62899, compounds represented by formula (I) of JP-A-10-186572, and specific examples thereof include paragraph numbers 0033 to 0052. , European Patent Publication No. 0803764A1, page 20, lines 36-56. Of these, mercapto-substituted heteroaromatic compounds described in JP-A-9-297367, JP-A-9-304875, JP-A-2001-100388, JP-A-2002-303955, JP-A-2002-303951, and the like are preferable.

2) Toning Agent In the photothermographic material of the present invention, it is preferable to add a toning agent. For the toning agent, paragraph Nos. 0054 to 0055 of JP-A No. 10-62899, page 21 to No. 23 of European Patent Publication No. 0803764A1. Line 48, described in JP-A No. 2000-356317 and JP-A No. 2000-187298, and in particular, phthalazinones (phthalazinone, phthalazinone derivatives or metal salts; for example, 4- (1-naphthyl) phthalazinone, 6-chlorophthalazinone. 5,7-dimethoxyphthalazinone and 2,3-dihydro-1,4-phthalazinedione); phthalazinones and phthalic acids (eg, phthalic acid, 4-methylphthalic acid, 4-nitrophthalic acid, diammonium phthalate) , Sodium phthalate, potassium phthalate and tetrachlorophthalic anhydride) Phthalazines (phthalazine, phthalazine derivatives or metal salts; for example, 4- (1-naphthyl) phthalazine, 6-isopropylphthalazine, 6-t-butylphthalazine, 6-chlorophthalazine, 5,7-dimethoxy Phthalazine and 2,3-dihydrophthalazine); a combination of phthalazines and phthalic acids is preferred, and a combination of phthalazines and phthalic acids is particularly preferred. Of these, a particularly preferred combination is a combination of 6-isopropylphthalazine and phthalic acid or 4-methylphthalic acid.

3) Plasticizers and lubricants Plasticizers and lubricants that can be used in the photosensitive layer of the present invention are described in paragraph No. 0117 of JP-A No. 11-65021. The slip agent is described in JP-A No. 11-84573, paragraph numbers 0061 to 0064 and Japanese Patent Application No. 11-106881, paragraph numbers 0049 to 0062.

4) Dye and Pigment The photosensitive layer of the present invention has various dyes and pigments (for example, CI Pigment Blue 60, CI Pigment, etc.) from the viewpoints of color tone improvement, prevention of interference fringes during laser exposure, and prevention of irradiation. Blue 64, CI Pigment Blue 15: 6) can be used. These are described in detail in WO98 / 36322, JP-A-10-268465, JP-A-11-338098 and the like.

5) Super-high contrast agent For the formation of a super-high contrast image suitable for printing plate making, it is preferable to add a super-high contrast agent to the image forming layer. As for the ultra-high contrast agent and its addition method and addition amount, the formulas of JP-A No. 11-65021, paragraph No. 0118, JP-A No. 11-223898, paragraph Nos. 0136 to 0193, and Japanese Patent Application No. 11-87297 are disclosed. (H), compounds of formulas (1) to (3), compounds of formulas (A) and (B), compounds of general formulas (III) to (V) described in Japanese Patent Application No. 11-91652 (specific compounds) : Chemical Formula 21 to Chemical Formula 24), and the high contrast accelerator are described in paragraph No. 0102 of JP-A No. 11-65021 and paragraph Nos. 0194 to 0195 of JP-A No. 11-223898.

In order to use formic acid or formate as a strong fogging substance, it is preferably contained at 5 mmol or less, more preferably 1 mmol or less, per mol of silver on the side having the image forming layer containing photosensitive silver halide.
When the ultrahigh contrast agent is used in the photothermographic material of the present invention, it is preferable to use an acid formed by hydrating diphosphorus pentoxide or a salt thereof in combination. Acids or salts thereof formed by hydration of diphosphorus pentoxide include metaphosphoric acid (salt), pyrophosphoric acid (salt), orthophosphoric acid (salt), triphosphoric acid (salt), tetraphosphoric acid (salt), hexametalin An acid (salt) etc. can be mentioned. Examples of the acid or salt thereof formed by hydrating diphosphorus pentoxide particularly preferably include orthophosphoric acid (salt) and hexametaphosphoric acid (salt). Specific examples of the salt include sodium orthophosphate, sodium dihydrogen orthophosphate, sodium hexametaphosphate, ammonium hexametaphosphate and the like.
The amount of acid or salt thereof formed by hydration of diphosphorus pentoxide (the coating amount per 1 m ^{2 of} photosensitive material) may be a desired amount according to the performance such as sensitivity and fog, but is 0.1 mg / m ^2. ˜500 mg / m ² is preferable, and 0.5 mg / m ^{2 to} 100 mg / m ² is more preferable.

(Preparation and application of coating solution)
The preparation temperature of the image forming layer coating solution of the present invention is preferably from 30 ° C. to 65 ° C., more preferably from 35 ° C. to less than 60 ° C., and more preferably from 35 ° C. to 55 ° C.
Moreover, it is preferable that the temperature of the image forming layer coating liquid immediately after the addition of the polymer latex is maintained at 30 ° C. or higher and 65 ° C. or lower.

(Layer structure and components)
The image forming layer of the present invention is composed of one or more layers on a support. In the case of a single layer, it consists of an organic silver salt, a photosensitive silver halide, a reducing agent and a binder, and optionally contains additional materials such as toning agents, coating aids and other auxiliary agents. In the case of two or more layers, an organic silver salt and a light-sensitive silver halide are contained in the first image forming layer (usually a layer adjacent to the support), and some in the second image forming layer or both layers. Must contain other ingredients. The construction of a multicolor photosensitive photothermographic material may include a combination of these two layers for each color and all components in a single layer as described in US Pat. No. 4,708,928. May be included. In the case of multi-dye multicolor photosensitive photothermographic materials, each emulsion layer is generally functional or non-functional between each photosensitive layer as described in US Pat. No. 4,460,681. By using different barrier layers, they are distinguished from each other and held.
The photothermographic material of the present invention can have a non-photosensitive layer in addition to the image forming layer. The non-photosensitive layer includes (a) a surface protective layer provided on the image forming layer (on the side farther than the support), (b) between the plurality of image forming layers and between the image forming layer and the protective layer. It can be classified into an intermediate layer provided therebetween, (c) an undercoat layer provided between the image forming layer and the support, and (d) a back layer provided on the opposite side of the image forming layer.

  In addition, although a layer acting as an optical filter can be provided, it is provided as the layer (a) or (b). The antihalation layer is provided on the photosensitive material as the layer (c) or (d).

1) Surface protective layer The photothermographic material according to the invention may be provided with a surface protective layer for the purpose of preventing adhesion of the image forming layer. The surface protective layer may be a single layer or a plurality of layers.
The surface protective layer is described in JP-A No. 11-65021, paragraph numbers 0119 to 0120 and JP-A No. 2000-171936.
As the binder for the surface protective layer of the present invention, gelatin is preferable, but it is also preferable to use polyvinyl alcohol (PVA) or a combination thereof. As gelatin, inert gelatin (for example, Nitta gelatin 750), phthalated gelatin (for example, Nitta gelatin 801), and the like can be used. Examples of PVA include those described in paragraph Nos. 0009 to 0020 of JP-A No. 2000-171936. Completely saponified PVA-105, partially saponified PVA-205, PVA-335, and modified polyvinyl alcohol MP- Preferred is 203 (trade name, manufactured by Kuraray Co., Ltd.). Preferably 0.3g / m ² ~4.0g / m ² as a polyvinyl alcohol coating amount (per support 1 m ²⁾ of the protective layer (per one ^{layer), 0.3g / m 2 ~2.0g /} m 2 Is more preferable.

All (including water-soluble polymer and latex polymer) binder preferably 0.3g / m ² ~5.0g / m ² as a coating amount (per support 1 m ²⁾ of the surface protective layer (per one layer), 0. 3g / m ² ~2.0g / m ² is more preferable.

2) Antihalation layer In the photothermographic material of the invention, the antihalation layer can be provided on the side farther from the light source than the photosensitive layer.

As for the antihalation layer, paragraphs 0123 to 0124 of JP-A-11-65021, JP-A-11-223898, 9-230531, 10-36695, 10-104779, 11-231457, 11 -352625, 11-352626 and the like.
The antihalation layer contains an antihalation dye having absorption at the exposure wavelength. When the exposure wavelength is in the infrared region, an infrared absorbing dye may be used, and in that case, a dye having no absorption in the visible region is preferable.
When antihalation is performed using a dye having absorption in the visible range, it is preferable that substantially no dye color remains after image formation, and a means for decoloring by the heat of heat development is used. In particular, it is preferable to add a thermally decolorable dye and a base precursor to the non-photosensitive layer to function as an antihalation layer. These techniques are described in JP-A-11-231457 and the like.

The amount of decoloring dye added is determined by the use of the dye. In general, the optical density (absorbance) measured at the target wavelength is used in an amount exceeding 0.1. The optical density is preferably 0.15 to 2, and more preferably 0.2 to 1. The amount of the dye for obtaining such an optical density is generally 0.001g / m ² ~1g / m ² approximately.

When the dye is decolored in this way, the optical density after heat development can be reduced to 0.1 or less. Two or more kinds of decoloring dyes may be used in combination in a heat decoloring type recording material or a photothermographic material. Similarly, two or more kinds of base precursors may be used in combination.
In the thermal decoloration using such decoloring dye and base precursor, a substance (for example, diphenylsulfone, which lowers the melting point by 3 ° C. (deg) or more when mixed with a base precursor as described in JP-A No. 11-352626). 4-Chlorophenyl (phenyl) sulfone), 2-naphthyl benzoate and the like are preferably used in view of thermal decoloring properties.

3) Back Layer Back layers that can be applied to the present invention are described in paragraph Nos. 0128 to 0130 of JP-A No. 11-65021.

In the present invention, a colorant having an absorption maximum at 300 nm to 450 nm can be added for the purpose of improving the silver tone and the temporal change of the image. Such colorants are disclosed in JP-A-62-210458, JP-A-63-104046, JP-A-63-103235, JP-A-63-208846, JP-A-63-306436, JP-A-63-141435, and JP-A-01-61745. No. 1, Japanese Patent Laid-Open No. 2001-100363, and the like.
Such a colorant is usually added in the range of 0.1 mg / m ^{2 to 1} g / m ² , and the back layer provided on the opposite side of the photosensitive layer is preferable as the layer to be added.
In order to adjust the base color tone, it is preferable to use a dye having an absorption peak at 580 to 680 nm. As the dye for this purpose, azomethine oil-soluble dyes described in JP-A-4-359967 and JP-A-4-359968, which have a small absorption intensity on the short wavelength side, and phthalocyanine water-soluble dyes described in Japanese Patent Application No. 2002-96797 are preferable. The dye for this purpose may be added to any layer, but is more preferably added to the non-photosensitive layer on the emulsion surface side or the back surface side.

  The photothermographic material in the invention is a so-called single-sided photosensitive material having a photosensitive layer containing at least one silver halide emulsion on one side of a support and a back layer on the other side. preferable.

4) Matting Agent In the present invention, it is preferable to add a matting agent for improving transportability, and the matting agent is described in paragraph Nos. 0126 to 0127 of JP-A No. 11-65021. When the matting agent is indicated by the coating amount per the photosensitive material 1 m ^2, preferably from ^{1mg / m 2 ~400mg / m 2} , more preferably ^{5mg / m 2 ~300mg / m 2} .
In the present invention, the shape of the matting agent may be either a regular shape or an irregular shape, but is preferably a regular shape, and a spherical shape is preferably used. The average particle size is preferably 0.5 to 10 μm, more preferably 1.0 μm to 8.0 μm, and still more preferably 2.0 μm to 6.0 μm.
The variation coefficient of the size distribution is preferably 50% or less, more preferably 40% or less, and still more preferably 30% or less. Here, the coefficient of variation is a value represented by (standard deviation of particle size) / (average value of particle size) × 100. It is also preferable to use two types of matting agents having a small variation coefficient and having an average particle size ratio larger than 3.
The emulsion surface may have any matte degree as long as no stardust failure occurs, but the Beck smoothness is preferably 30 seconds or more and 2000 seconds or less, and particularly preferably 40 seconds or more and 1500 seconds or less. The Beck smoothness can be easily determined by Japanese Industrial Standard (JIS) P8119 "Smoothness test method using Beck tester for paper and paperboard" and TAPPI standard method T479.

  In the present invention, the matte degree of the back layer is preferably a Beck smoothness of 1200 seconds or less and 10 seconds or more, preferably 800 seconds or less and 20 seconds or more, and more preferably 500 seconds or less and 40 seconds or more.

  In the present invention, the matting agent is preferably contained in the outermost surface layer of the photosensitive material, the layer functioning as the outermost surface layer, or a layer close to the outer surface, and is contained in a layer acting as a so-called protective layer. It is preferable.

5) Polymer Latex When the photothermographic material of the present invention is used for printing applications in which dimensional change is a problem, it is preferable to use a polymer latex for the surface protective layer or the back layer. For such polymer latex, “Synthetic resin emulsion (Hiraku Okuda, Hiroshi Inagaki, published by Kobunshi Publishing (1978))”, “Application of synthetic latex (Takaaki Sugimura, Ikuo Kataoka, Junichi Suzuki, Keiji Kasahara, Takashi "Molecular Publications (1993))" and "Synthetic Latex Chemistry (Muroichi Muroi, published by High Polymers Publication (1970))", specifically, methyl methacrylate (33.5% by mass) / Ethyl acrylate (50 wt%) / methacrylic acid (16.5 wt%) copolymer latex, methyl methacrylate (47.5 wt%) / butadiene (47.5 wt%) / itaconic acid (5 wt%) copolymer Latex, latex of ethyl acrylate / methacrylic acid copolymer, methyl methacrylate (58.9% by mass) / 2-ethyl Latex of xyl acrylate (25.4 mass%) / styrene (8.6 mass%) / 2-hydroxyethyl methacrylate (5.1 mass%) / acrylic acid (2.0 mass%) copolymer, methyl methacrylate (64. 0 mass%) / styrene (9.0 mass%) / butyl acrylate (20.0 mass%) / 2-hydroxyethyl methacrylate (5.0 mass%) / acrylic acid (2.0 mass%) copolymer latex, etc. Is mentioned.
Furthermore, as a binder for the surface protective layer, a combination of polymer latex described in Japanese Patent Application No. 11-6872 and a technique described in Paragraph Nos. 0021 to 0025 of Japanese Patent Application Laid-Open No. 2000-267226, Japanese Patent Application No. 11-6872 The technology described in paragraph numbers 0027 to 0028 of the specification and the technology described in paragraph numbers 0023 to 0041 of JP 2000-19678 may be applied. The ratio of the polymer latex in the surface protective layer is preferably 10% by mass or more and 90% by mass or less, and particularly preferably 20% by mass or more and 80% by mass or less of the total binder.

6) Membrane pH
The photothermographic material of the present invention preferably has a film surface pH of 7.0 or less, more preferably 6.6 or less before heat development. The lower limit is not particularly limited, but is about 3. The most preferred pH range is in the range of 4 to 6.2. For the adjustment of the film surface pH, it is preferable to use an organic acid such as a phthalic acid derivative, a non-volatile acid such as sulfuric acid, and a volatile base such as ammonia from the viewpoint of reducing the film surface pH. In particular, ammonia is volatile and is preferable for achieving a low film surface pH because it can be removed before the coating process or heat development.
In addition, it is also preferable to use ammonia in combination with a nonvolatile base such as sodium hydroxide, potassium hydroxide, or lithium hydroxide. In addition, the measuring method of film surface pH is described in paragraph number 0123 of Unexamined-Japanese-Patent No. 2000-284399.

7) Hardener A hardener may be used for each layer such as the photosensitive layer, protective layer, and back layer of the present invention. Examples of hardeners include T.W. H. There are various methods described in "THE THEORY OF THE PHOTOGRAPHIC PROCESS FOURTH EDITION" by James (published by Macmillan Publishing Co., Inc., published in 1977), pages 77 to 87. -S-triazine sodium salt, N, N-ethylenebis (vinylsulfoneacetamide), N, N-propylenebis (vinylsulfoneacetamide), polyvalent metal ions described on page 78 thereof, U.S. Pat. No. 4,281, Polyisocyanates such as 060 and JP-A-6-208193, epoxy compounds such as US Pat. No. 4,791,042, and vinyl sulfone compounds such as JP-A 62-89048 are preferably used.

  The hardening agent is added as a solution, and the addition time of this solution into the protective layer coating solution is from 180 minutes before to immediately before application, preferably from 60 minutes to 10 seconds before application. As long as the effects of the present invention are sufficiently exhibited, there is no particular limitation. Specific mixing methods include mixing in a tank in which the average residence time calculated from the addition flow rate and the amount of liquid fed to the coater is a desired time, and N.I. Harnby, M.M. F. Edwards, A.D. W. There is a method using a static mixer described in Chapter 8 of Nienow's Koji Takahashi "Liquid Mixing Technology" (published by Nikkan Kogyo Shimbun, 1989).

8) Surfactant As for the surfactant applicable to the present invention, paragraph No. 0132 of JP-A No. 11-65021, paragraph No. 0133 of the solvent, paragraph No. 0134 of the support, antistatic or conductive layer Paragraph No. 0135 for the method of obtaining a color image, paragraph No. 0136 for JP-A No. 11-84573 and paragraph Nos. 0049 to 0062 of Japanese Patent Application No. 11-106881 for the slip agent. Has been.
In the present invention, it is preferable to use a fluorosurfactant. Specific examples of the fluorosurfactant include compounds described in JP-A Nos. 10-197985, 2000-19680, 2000-214554 and the like. Further, a polymeric fluorine-based surfactant described in JP-A-9-281636 is also preferably used.
In the photothermographic material of the present invention, it is preferable to use a fluorosurfactant described in JP-A No. 2002-82411, Japanese Patent Application Nos. 2001-242357 and 2001-264110. In particular, the fluorosurfactants described in Japanese Patent Application Nos. 2001-242357 and 2001-264110 are preferable in terms of charge adjustment ability, stability of the coated surface, and smoothness when coating and manufacturing with an aqueous coating solution. The fluorine-containing surfactant described in Japanese Patent Application No. 2001-264110 is most preferable in that it has a high charge adjustment capability and requires a small amount of use.
In the present invention, the fluorosurfactant can be used on either the emulsion surface or the back surface, and is preferably used on both surfaces. Further, it is particularly preferable to use in combination with a conductive layer containing the above-described metal oxide. In this case, sufficient performance can be obtained even if the amount of the fluorosurfactant used on the surface having the conductive layer is reduced or removed.
The preferred amount of the fluorocarbon surfactant is emulsion surface, ranging back surface each ^{0.1mg / m 2 ~100mg / m 2} , more preferably 0.3mg / m ² ~30mg / m ² range, further preferably in the range of ^{1mg / m 2 ~10mg / m 2} . Especially, the fluorocarbon surfactant described in Japanese Patent Application No. 2001-264110 is effective, and preferably in the range of ^{0.01mg / m 2 ~10mg / m 2} , more in the range of 0.1mg / m ² ~5mg / m ² preferable.

9) Antistatic agent In this invention, it is preferable to have a conductive layer containing a metal oxide or a conductive polymer. The antistatic layer may serve as an undercoat layer, a back layer surface protective layer, or the like, or may be provided separately. As the conductive material for the antistatic layer, a metal oxide in which conductivity is improved by introducing oxygen defects or different metal atoms into the metal oxide is preferably used. Examples of metal oxides are preferably ZnO, TiO ₂ and SnO _2. Addition of Al and In to ZnO, addition of Sb, Nb, P and halogen elements to SnO ₂ , and addition to TiO _2. For example, addition of Nb, Ta or the like is preferable. In particular, SnO ₂ added with Sb is preferable. The amount of different atoms added is preferably in the range of 0.01 to 30 mol%, more preferably in the range of 0.1 to 10 mol%. The shape of the metal oxide may be spherical, needle-like, or plate-like, but the long axis / uniaxial ratio is 2.0 or more, preferably 3.0 to 50 in terms of the effect of imparting conductivity. Good. Range amount preferably of 1mg / m ² ~1000mg / m ² of metal oxide, more preferably 10mg / m ² ~500mg / m ² range, more preferably at 20mg / m ² ~200mg / m ² It is a range.
The antistatic layer of the present invention may be disposed on either the emulsion surface side or the back surface side, but is preferably disposed between the support and the back layer. Specific examples of the antistatic layer of the present invention include paragraph No. 0135 of JP-A No. 11-65021, JP-A Nos. 56-143430, 56-143431, 58-62646, No. 56-120519, JP-A No. 11-120. No. 84573, paragraph numbers 0040 to 0051, US Pat. No. 5,575,957, and JP-A No. 11-223898, paragraph numbers 0078 to 0084.

10) Support The transparent support was subjected to a heat treatment in a temperature range of 130 to 185 ° C. in order to relieve internal strain remaining in the film during biaxial stretching and to eliminate heat shrinkage strain generated during heat development processing. Polyester, particularly polyethylene terephthalate is preferably used. In the case of a photothermographic material for medical use, the transparent support may be colored with a blue dye (for example, dye-1 described in Examples of JP-A-8-240877) or may be uncolored. Examples of the support include water-soluble polyesters disclosed in JP-A-11-84574, styrene-butadiene copolymers described in JP-A-10-186565, and vinylidene chloride described in JP-A-2000-39684 and Japanese Patent Application No. 11-106881, paragraphs 0063-0080. It is preferable to apply an undercoating technique such as a copolymer. When the emulsion layer or the back layer is coated on the support, the water content of the support is preferably 0.5% by mass or less.

11) Other additives An antioxidant, a stabilizer, a plasticizer, an ultraviolet absorber or a coating aid may be further added to the photothermographic material. Various additives are added to either the photosensitive layer or the non-photosensitive layer. With respect to these, WO 98/36322, EP 803764A1, JP-A-10-186567, 10-18568 and the like can be referred to.

12) Coating method The photothermographic material in the invention may be coated by any method. Specifically, various coating operations including extrusion coating, slide coating, curtain coating, dip coating, knife coating, flow coating, or extrusion coating using a hopper of the type described in US Pat. No. 2,681,294. And Stephen F. Kistler, Peter M. et al. Extrusion coating or slide coating described in pages 399 to 536 of "LIQUID FILM COATING" (CHAPMAN & HALL, 1997) by Schweizer is preferably used, and slide coating is particularly preferably used. An example of the shape of a slide coater used for slide coating is shown in FIG. 11b. 1 If desired, two or more layers can be simultaneously coated by the method described on pages 399 to 536 of the same document, the method described in US Pat. No. 2,761,791 and British Patent No. 837,095. .
In the present invention, particularly preferred coating methods are those described in JP-A Nos. 2001-194748, 2002-153808, 2002-153803, and 2002-182333.

The organic silver salt-containing layer coating solution in the present invention is preferably a so-called thixotropic fluid. Regarding this technique, JP-A-11-52509 can be referred to. The organic silver salt-containing layer coating solution in the present invention preferably has a viscosity at a shear rate of 0.1 S ⁻¹ of 400 mPa · s to 100,000 mPa · s, more preferably 500 mPa · s to 20,000 mPa · s. is there. Further, at a shear rate of 1000 S ^−1, it is preferably 1 mPa · s or more and 200 mPa · s or less, and more preferably 5 mPa · s or more and 80 mPa · s or less.

In the case of preparing the coating liquid of the present invention, a known in-line mixer or implant mixer is preferably used when mixing two kinds of liquids.
A preferred in-line mixer of the present invention is described in JP-A No. 2002-85948, and an implant mixer is described in JP-A No. 2002-90940.
The coating solution in the present invention is preferably subjected to defoaming treatment in order to keep the coated surface state good. A preferable defoaming treatment method of the present invention is the method described in JP-A No. 2002-66431.
When applying the coating solution of the present invention, it is preferable to perform static elimination in order to prevent adhesion of dust, dust, and the like due to electric resistance of the support.
An example of a preferable static elimination method in the present invention is described in JP-A No. 2002-143747.
In the present invention, it is important to precisely control the drying air and the drying temperature in order to dry the non-setting image forming layer coating solution. The preferred drying method of the present invention is described in detail in JP-A Nos. 2001-194749 and 2002-139814.
The photothermographic material of the present invention is preferably subjected to a heat treatment immediately after coating and drying in order to improve film formability. The temperature of the heat treatment is preferably in the range of 60 ° C. to 100 ° C. as the film surface temperature, and the heating time is preferably in the range of 1 second to 60 seconds. A more preferable range is a film surface temperature of 70 to 90 ° C. and a heating time of 2 seconds to 10 seconds.
A preferable heat treatment method of the present invention is described in JP-A No. 2002-107872.
In order to stably and continuously produce the photothermographic material of the present invention, the production methods described in JP-A Nos. 2002-156728 and 2002-182333 are preferably used.

  The photothermographic material is preferably a mono-sheet type (a type capable of forming an image on the photothermographic material without using another sheet such as an image receiving material).

13) Packaging material The photosensitive material of the present invention is packaged with a packaging material having a low oxygen permeability and / or moisture permeability in order to suppress fluctuations in photographic performance during raw storage or to improve curling, curling, etc. It is preferable. The oxygen permeability is preferably 50 ml / atm · m ² · day or less at 25 ° C., more preferably 10 ml / atm · m ² · day or less, more preferably 1.0 ml / atm · m ² · day or less. is there. The moisture permeability is preferably 10 g / atm · m ² · day or less, more preferably 5 g / atm · m ² · day or less, and still more preferably 1 g / atm · m ² · day or less.
Specific examples of the packaging material having a low oxygen permeability and / or moisture permeability are disclosed in, for example, JP-A-8-254793. This is a packaging material described in JP-A-2000-206653.
14) Other available technologies

  Techniques that can be used for the photothermographic material of the present invention include EP80364A1, EP883022A1, WO98 / 36322, JP56-62648, 58-62644, JP9-43766, and 9-. 281637, 9-297367, 9-304869, 9-311405, 9-329865, 10-10669, 10-62899, 10-69023, 10-186568, 10-90823, 10-171106, 10-186565, 10-186567, 10-186567 to 10-186572, 10-197974, 10-197982, 10 -197983, 10-197985 to 10-197987, 10- 07001, 10-207004, 10-221807, 10-282601, 10-288823, 10-288824, 10-307365, 10-312038, 10-339934 11-7100, 11-15105, 11-24200, 11-24201, 11-30201, 11-30832, 11-84574, 11-65021, 11-109547, 11-125880, 11-129629, 11-133536 to 11-133539, 11-133542, 11-133543, 11-223898, 11-352627, 11- 305377, 11-305378, 11-305384, 11-30538 11-316435, 11-327076, 11-338096, 11-338098, 11-338099, 11-343420, JP 2000-187298, 2000-10229 2000-47345, 2000-206642, 2000-98530, 2000-98531, 2000-112059, 2000-112060, 2000-112104, 2000-112604, No. 2000-171936 is also mentioned.

In the case of a multicolor color photothermographic material, each emulsion layer is generally a functional or non-functional barrier layer between each photosensitive layer as described in U.S. Pat. No. 4,460,681. Are used to keep them distinguished from each other.
The construction in the case of a multicolor color photothermographic material may include a combination of these two layers for each color and all within a single layer as described in US Pat. No. 4,708,928. Ingredients may be included.

(Image forming method)
1) Exposure Red to infrared emission He—Ne laser, red semiconductor laser, blue to green emission Ar ⁺ , He—Ne, He—Cd laser, blue semiconductor laser. Preferred is a red to infrared semiconductor laser, and the peak wavelength of the laser light is 600 nm to 900 nm, preferably 620 nm to 850 nm. On the other hand, in recent years, in particular, a module in which an SHG (Second Harmonic Generator) element and a semiconductor laser are integrated and a blue semiconductor laser have been developed, and a laser output device in a short wavelength region has been closed up. The blue semiconductor laser is expected to increase in demand in the future because high-definition image recording is possible, the recording density is increased, and a stable output is obtained with a long lifetime. The peak wavelength of the blue laser light is preferably 300 nm to 500 nm, particularly preferably 400 nm to 500 nm.
It is also preferable that the laser light is oscillated in a vertical multi by a method such as high frequency superposition.

2) Photothermographic development The photothermographic material of the present invention may be developed by any method, but is usually developed by raising the temperature of the photothermographic material exposed imagewise. The preferred development temperature is 80 to 250 ° C, preferably 100 to 140 ° C, more preferably 110 to 130 ° C. The development time is preferably 1 second to 60 seconds, more preferably 3 seconds to 30 seconds, and even more preferably 5 seconds to 25 seconds.

  Either a drum type heater or a plate type heater may be used as the thermal development method, but the plate type heater method is more preferable. The heat development method using the plate type heater method is preferably a method described in JP-A-11-133572, and a visible image is obtained by bringing a photothermographic material having a latent image formed thereon into contact with a heating means in a heat developing unit. In the heat development apparatus, the heating unit includes a plate heater, and a plurality of press rollers are disposed to face each other along one surface of the plate heater, and the press roller is disposed between the press roller and the plate heater. A heat development apparatus characterized in that heat development is performed by passing a photothermographic material. It is preferable to divide the plate heater into 2 to 6 stages and lower the temperature about 1 to 10 ° C. at the tip. For example, there are examples in which four sets of plate heaters that can be independently controlled are used and controlled so as to be 112 ° C., 119 ° C., 121 ° C., and 120 ° C. Such a method is also described in JP-A-54-30032, which can exclude moisture and organic solvents contained in the photothermographic material out of the system, and rapidly develop the photothermographic material. It is also possible to suppress a change in the shape of the support of the photothermographic material due to the heating.

In order to reduce the size of the heat developing machine and shorten the heat development time, it is preferable to be able to control the heater more stably. In addition, the exposure of one sheet of photosensitive material is started from the top and the exposure is finished to the rear end. It is desirable to start the heat development before the time.
Imagers capable of rapid processing preferable for the present invention are described in, for example, JP-A Nos. 2002-289804 and 2002-287668.

3) System As a medical laser imager provided with an exposure part and a heat development part, Fuji Medical Dry Laser Imager FM-DPL and DRYPIX7000 can be exemplified. Regarding FM-DPL, Fuji Medical Review No. 8, pages 39 to 55, and it goes without saying that those techniques are applied as a laser imager of the photothermographic material of the present invention. Further, it can also be applied as a photothermographic material for a laser imager in “AD network” proposed by Fuji Film Medical Co., Ltd. as a network system adapted to the DICOM standard.

(Use of the present invention)
The photothermographic material of the present invention forms a black and white image by a silver image, and is used as a photothermographic material for medical diagnosis, a photothermographic material for industrial photography, a photothermographic material for printing, and a photothermographic material for COM. It is preferably used.

EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples.
Example 1

(Preparation of PET support)
1) Film formation)
Using terephthalic acid and ethylene glycol, PET having an intrinsic viscosity of IV = 0.66 (measured at 25 ° C. in phenol / tetrachloroethane = 6/4 (weight ratio)) was obtained according to a conventional method. This was pelletized, dried at 130 ° C. for 4 hours, melted at 300 ° C., extruded from a T-die and quenched, and an unstretched film having a thickness of 175 μm after heat setting was prepared.

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

2) Surface corona treatment Both surfaces of the support were treated at room temperature at 20 m / min using a solid state corona treatment machine 6KVA model manufactured by Pillar. From the current and voltage readings at this time, it was found that the support was processed at 0.375 kV · A · min / m ² . The treatment frequency at this time was 9.6 kHz, and the gap clearance between the electrode and the dielectric roll was 1.6 mm.

3) Undercoat 1) Preparation formulation of undercoat layer coating solution (1) (for photosensitive layer side undercoat layer)
59 g of pesresin A-520 (30% by mass solution) manufactured by Takamatsu Yushi Co., Ltd.
Polyethylene glycol monononyl phenyl ether (average number of ethylene oxides = 8.5) 10% by mass solution 5.4 g
MP-1000 (polymer fine particles, average particle size 0.4 μm) manufactured by Soken Chemical Co., Ltd.
0.91g
935 ml of distilled water

Formula (2) (for back layer 1st layer)
Styrene-butadiene copolymer latex 158g
(Solid content 40% by mass, styrene / butadiene weight ratio = 68/32)
2,4-dichloro-6-hydroxy-S-triazine sodium salt (8% by mass aqueous solution)
20g
10% 1% by weight aqueous solution of sodium laurylbenzenesulfonate
854 ml of distilled water

Formula (3) (for back side second layer)
SnO ₂ / SbO (9/1 mass ratio, average particle size 0.038 μm, 17 mass% dispersion)
84g
Gelatin (10 mass% aqueous solution) 89.2g
8.6 g, manufactured by Shin-Etsu Chemical Co., Ltd.
MP-1000 0.01g by Soken Chemical Co., Ltd.
10% 1% by weight aqueous solution of sodium dodecylbenzenesulfonate
NaOH (1% by mass) 6 ml
Proxel (ICI) 1ml
805 ml of distilled water

2) Undercoat After the corona discharge treatment is performed on both surfaces of the biaxially stretched polyethylene terephthalate support having a thickness of 175 μm, the undercoat coating solution formulation (1) is wet coated with a wire bar on one surface (photosensitive layer surface). Apply to a volume of 6.6 ml / m ² (per side) and dry at 180 ° C. for 5 minutes, and then wet coat the above-mentioned undercoat coating liquid formulation (2) on the back side (back side) with a wire bar. Was applied at a temperature of 5.7 ml / m ² , dried at 180 ° C. for 5 minutes, and the wet coating amount of the undercoat coating liquid formulation (3) on the back surface (back surface) was 7.7 ml / m with a wire bar. ² was applied and dried at 180 ° C. for 6 minutes to prepare an undercoat support.

(Back layer)
1) Preparation of back layer coating solution (Preparation of solid fine particle dispersion (a) of base precursor)
2.5 kg of the base precursor compound 1 and 300 g of a surfactant (trade name: Demol N, manufactured by Kao Corporation), 800 g of diphenylsulfone, 1.0 g of benzoisothiazolinone sodium salt and distilled water were added to make a total amount of 8 Then, the mixture was dispersed with beads using a horizontal sand mill (UVM-2: manufactured by Imex Co., Ltd.). In the dispersion method, the mixed solution was fed to UVM-2 filled with zirconia beads having an average diameter of 0.5 mm by a diaphragm pump, and dispersed at an internal pressure of 50 hPa or more until a desired average particle size was obtained.
The dispersion was subjected to spectral absorption measurement, and the ratio of the absorbance at 450 nm to the absorbance at 650 nm (D ₄₅₀ / D ₆₅₀ ) in the spectral absorption of the dispersion was dispersed to 3.0. The obtained dispersion was diluted with distilled water so that the concentration of the base precursor was 25% by mass, and was filtered for removal of dust (polypropylene filter having an average pore size of 3 μm) for practical use.

2) Preparation of Dye Solid Fine Particle Dispersion 6.0 kg of cyanine dye compound-1 and 3.0 kg of sodium p-dodecylbenzenesulfonate, 0.6 kg of surfactant Demol SNB manufactured by Kao Corporation, and antifoaming agent (trade name) : Surfynol 104E, manufactured by Nissin Chemical Co., Ltd.) 0.15 kg was mixed with distilled water to make a total liquid volume of 60 kg. The mixed solution was dispersed with 0.5 mm zirconia beads using a horizontal sand mill (UVM-2: manufactured by Imex Corporation).
The dispersion was dispersed until the ratio of the absorbance at 650 nm to the absorbance at 750 nm (D ₆₅₀ / D ₇₅₀ ) in the spectral absorption of the dispersion was 5.0 or more. The obtained dispersion was diluted with distilled water so that the concentration of the cyanine dye was 6% by mass, and subjected to filter filtration (average pore size: 1 μm) for removing dust.

3) Preparation of antihalation layer coating solution Keep container at 40 ° C., gelatin 40 g, monodisperse polymethyl methacrylate fine particles (average particle size 8 μm, particle size standard deviation 0.4) 20 g, benzoisothiazolinone 0.1 g, 490 ml of water was added to dissolve the gelatin. Furthermore, 2.3 ml of 1 mol / l sodium hydroxide aqueous solution, 40 g of the dye solid fine particle dispersion, 90 g of the solid fine particle dispersion (a) of the base precursor, 12 ml of 3% by weight aqueous sodium polystyrenesulfonate solution, 10% by weight of SBR latex The liquid 180g was mixed. Immediately before coating, 80 ml of a 4% by weight aqueous solution of N, N-ethylenebis (vinylsulfonacetamide) was mixed to prepare a coating solution for preventing halation.

4) Preparation of back surface protective layer coating solution The container was kept at 40 ° C., and gelatin was dissolved by adding 40 g of gelatin, 35 mg of benzoisothiazolinone and 840 ml of water. Further, 5.8 ml of 1 mol / l sodium hydroxide aqueous solution, 1.5 g of liquid paraffin emulsion as liquid paraffin, 10 ml of 5% by weight aqueous solution of di (2-ethylhexyl) sodium sulfosuccinate, 20 ml of 3% by weight aqueous sodium polystyrene sulfonate solution , 2.4 ml of a fluorine-based surfactant (F-1) 2% by weight solution, 2.4 ml of a fluorine-based surfactant (F-2) 2% by weight solution, methyl methacrylate / styrene / butyl acrylate / hydroxyethyl methacrylate / Acrylic acid copolymer (copolymerization weight ratio 57/8/28/5/2) Latex 19% by mass solution 32 g was mixed. Immediately before coating, 25 ml of a 4% by weight aqueous solution of N, N-ethylenebis (vinylsulfonacetamide) was mixed to prepare a coating solution for the back surface protective layer.

4) Application of back layer On the back surface side of the undercoat support, an antihalation layer coating solution was applied so that the gelatin coating amount was 0.52 g / m ^2, and a back surface protective layer coating solution was applied with a gelatin coating amount of 1 A simultaneous multi-layer coating was applied so as to be 7 g / m ² , followed by drying to form a back layer.

(Image forming layer, intermediate layer, and surface protective layer)
1. Preparation of coating materials 1) Silver halide emulsion (Preparation of silver halide emulsion 1)
A solution prepared by adding 3.1 ml of 1% by mass potassium bromide solution to 1421 ml of distilled water and further adding 3.5 ml of 0.5 mol / L sulfuric acid and 31.7 g of phthalated gelatin was stirred in a stainless steel reaction vessel. While maintaining the liquid temperature at 30 ° C., the solution A diluted with 92.2 ml of distilled water added to 22.22 g of silver nitrate, 15.3 g of potassium bromide and 0.8 g of potassium iodide in a distilled water volume of 97.4 ml. Solution B diluted in a total amount was added at a constant flow rate over 45 seconds. Thereafter, 10 ml of a 3.5% by mass aqueous hydrogen peroxide solution was added, and 10.8 ml of a 10% by mass aqueous solution of benzimidazole was further added. Further, a solution C in which distilled water was added to 51.86 g of silver nitrate to be diluted to 317.5 ml, a solution D in which 44.2 g of potassium bromide and 2.2 g of potassium iodide were diluted with distilled water to a volume of 400 ml was added to solution C. Was added at a constant flow rate over 20 minutes, and solution D was added by the controlled double jet method while maintaining pAg at 8.1. The total amount of potassium hexachloroiridium (III) was added 10 minutes after the start of the addition of Solution C and Solution D so that it would be 1 × 10 ⁻⁴ mole per mole of silver. Further, 5 seconds after the completion of the addition of the solution C, an aqueous solution of potassium iron (II) hexacyanide was added in an amount of 3 × 10 ⁻⁴ mol per mol of silver. The pH was adjusted to 3.8 using 0.5 mol / L sulfuric acid, stirring was stopped, and a precipitation / desalting / water washing step was performed. The pH was adjusted to 5.9 with 1 mol / L sodium hydroxide to prepare a silver halide dispersion having a pAg of 8.0.

The silver halide dispersion was maintained at 38 ° C. with stirring, 5 ml of a 0.34 mass% 1,2-benzisothiazolin-3-one methanol solution was added, and the temperature was raised to 47 ° C. after 40 minutes. 20 minutes after the temperature increase, sodium benzenethiosulfonate was added in a methanol solution to 7.6 × 10 ⁻⁵ moles per 1 mole of silver, and 5 minutes later, tellurium sensitizer C was added in a methanol solution at a rate of 2. per mol of silver. 9 × 10 ⁻⁴ mol was added and aged for 91 minutes. Thereafter, a methanol solution having a molar ratio of the spectral sensitizing dye A and the sensitizing dye B of 3: 1 was added in a total amount of 1.2 × 10 ⁻³ moles of the sensitizing dyes A and B per mole of silver. , N'-dihydroxy-N "-diethylmelamine in 1.3 ml of a 0.8 wt% methanol solution was added, and after another 4 minutes, 5-methyl-2-mercaptobenzimidazole was added to the methanol solution at a rate of 4.8 per mole of silver. × 10 ^-3 mol, 1-phenyl-2-heptyl-5-mercapto-1,3,4-triazole in methanol solution with 5.4 × 10 ^-3 mol and 1- (3-methyl with respect to 1 mol of silver A silver halide emulsion 1 was prepared by adding 8.5 × 10 ⁻³ mol of ureidophenyl) -5-mercaptotetrazole in an aqueous solution to 1 mol of silver.

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

(Preparation of silver halide emulsion 2)
In the preparation of silver halide emulsion 1, the liquid temperature at the time of grain formation was changed from 30 ° C. to 47 ° C., and solution B was changed to diluting 15.9 g of potassium bromide with distilled water to a volume of 97.4 ml, Solution D was changed to diluting 45.8 g of potassium bromide with distilled water to a volume of 400 ml, and the addition time of solution C was changed to 30 minutes to remove potassium hexacyanoiron (II) in the same manner. A silver halide emulsion 2 was prepared. Precipitation / desalting / washing / dispersion was carried out in the same manner as silver halide emulsion 1. Further, the addition amount of tellurium sensitizer C is 1.1 × 10 ⁻⁴ mol per mol of silver, and the addition amount of methanol solution of 3: 1 in the molar ratio of spectral sensitizing dye A and spectral sensitizing dye B is silver The total of sensitizing dye A and sensitizing dye B per mole is 7.0 × 10 ⁻⁴ mole, and 1-phenyl-2-heptyl-5-mercapto-1,3,4-triazole is added to 1 mole of silver. Same as Emulsion 1 except that 3.3 × 10 ⁻³ mol and 1- (3-methylureidophenyl) -5-mercaptotetrazole were changed to 4.7 × 10 ⁻³ mol added to 1 mol of silver. Spectral sensitization, chemical sensitization, and addition of 5-methyl-2-mercaptobenzimidazole and 1-phenyl-2-heptyl-5-mercapto-1,3,4-triazole were carried out to obtain silver halide emulsion 2. . The emulsion grains of the silver halide emulsion 2 were pure silver bromide cubic grains having an average sphere equivalent diameter of 0.080 μm and a sphere equivalent diameter variation coefficient of 20%.

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

(Preparation of mixed emulsion A for coating solution)
70% by weight of silver halide emulsion 1, 15% by weight of silver halide emulsion 2 and 15% by weight of silver halide emulsion 3 were dissolved, and benzothiazolium iodide was dissolved in a 1% by weight aqueous solution of 7% per mole of silver. × 10 ^-3 mol was added. Further, water is added so that the content of silver halide per 1 kg of the mixed emulsion for coating solution is 38.2 g as silver, and 1- (3-methylureidophenyl) is adjusted to 0.34 g per 1 kg of the mixed emulsion for coating solution. -5-mercaptotetrazole was added.
Further, as “a compound in which a one-electron oxidant produced by one-electron oxidation can emit one electron or more”, compounds 1 and 20 and 26 are each 2 × 10 ⁻³ per mole of silver halide. Molar amounts were added.

2) Preparation of fatty acid silver dispersion A 87.6 kg of behenic acid manufactured by Henkel (product name Edenor C22-85R), distilled water 423 L, 5 mol / L NaOH aqueous solution 49.2 L, t-butyl alcohol 120 L were mixed, The mixture was stirred and reacted at 75 ° C. for 1 hour to obtain a sodium behenate solution A. Separately, 206.2 L (pH 4.0) of an aqueous solution containing 40.4 kg of silver nitrate was prepared and kept warm at 10 ° C. A reaction vessel containing 635 L of distilled water and 30 L of t-butyl alcohol was kept at 30 ° C., and with sufficient stirring, the total amount of the previous sodium behenate solution A and the total amount of silver nitrate aqueous solution were kept at a constant flow rate for 93 minutes 15 Added over seconds and 90 minutes. At this time, only the aqueous silver nitrate solution is added for 11 minutes after the start of the addition of the aqueous silver nitrate solution, and then the addition of the sodium behenate solution A is started. After the addition of the aqueous silver nitrate solution is completed, only the sodium behenate solution A is added for 14 minutes and 15 seconds. Was added. At this time, the temperature in the reaction vessel was 30 ° C., and the external temperature was controlled so that the liquid temperature was constant. The pipe of the addition system of the sodium behenate solution A was prepared by keeping warm water by circulating hot water outside the double pipe so that the liquid temperature at the outlet of the addition nozzle tip was 75 ° C. Moreover, the piping of the addition system of the silver nitrate aqueous solution was kept warm by circulating cold water outside the double pipe. The addition position of the sodium behenate solution A and the addition position of the aqueous silver nitrate solution were arranged symmetrically around the stirring axis, and were adjusted so as not to contact the reaction solution.

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

  When the morphology of the obtained silver behenate particles was evaluated by electron microscope photography, the average values were a = 0.14 μm, b = 0.4 μm, c = 0.6 μm, average aspect ratio 5.2, average sphere equivalent diameter. It was a flake-like crystal having a variation coefficient of 15% for a sphere equivalent diameter of 0.52 μm. (A, b, and c are the text provisions)

  19.3 kg of polyvinyl alcohol (trade name: PVA-217) and water are added to a wet cake corresponding to a dry solid content of 260 kg to make a total amount of 1000 kg, and then slurried with a dissolver blade. : PM-10 type).

Next, the pre-dispersed stock solution is adjusted to 1260 kg / cm ² by adjusting the pressure of the disperser (trade name: Microfluidizer M-610, manufactured by Microfluidics International Corporation, using Z-type interaction chamber) three times. Treatment gave a silver behenate dispersion. The cooling operation was carried out by installing a serpentine heat exchanger before and after the interaction chamber, and adjusting the temperature of the refrigerant to a dispersion temperature of 18 ° C.

3) Preparation of reducing agent dispersion (Preparation of comparative reducing agent S-1 dispersion)
10 kg of water was added to 10 kg of a comparative reducing agent S-1 and 16 kg of a 10% by weight aqueous solution of modified polyvinyl alcohol (Kuraray Co., Ltd., Poval MP203) and mixed well to obtain a slurry. This slurry was fed with a diaphragm pump, dispersed for 3 hours in a horizontal sand mill (UVM-2: manufactured by Imex Co., Ltd.) filled with zirconia beads having an average diameter of 0.5 mm, and then benzoisothiazolinone sodium salt 0. 2 g and water were added to prepare a reducing agent concentration of 25% by mass. This dispersion was heat-treated at 60 ° C. for 5 hours to obtain a reducing agent-1 dispersion. The reducing agent particles contained in the reducing agent dispersion thus obtained had a median diameter of 0.40 μm and a maximum particle diameter of 1.4 μm or less. The obtained reducing agent dispersion was filtered through a polypropylene filter having a pore size of 3.0 μm to remove foreign substances such as dust and stored.

(Comparison of the reducing agent S-2 and the dispersion of the reducing agent of the present invention)
In the same manner as the dispersion preparation of the comparative reducing agent S-1, the comparative reducing agent S-2 is used instead of the comparative reducing agent S-1, and the reducing agent of the present invention is used as a comparative reducing agent S-. 2, and a dispersion of the reducing agent of the present invention was prepared. The reducing agent of the present invention used is shown in Table 1. The reducing agent particles contained in the obtained reducing agent dispersion were in the range of median diameter of 0.30 μm to 0.60 μm and the maximum particle diameter was 1.6 μm or less.

4) Preparation of color former dispersion of the present invention The color former dispersion of the present invention was prepared in the same manner as the above reducing agent dispersion. The color formers used are shown in Table 1. The color former particles contained in the obtained color former dispersion were in the median diameter range of 0.30 μm to 0.60 μm and the maximum particle diameter was 1.6 μm or less.

5) Preparation of Hydrogen Bonding Compound-1 Dispersion 10 kg of hydrogen bonding compound-1 (tri (4-t-butylphenyl) phosphine oxide) and modified polyvinyl alcohol (Kuraray Co., Ltd., Poval MP203) 10 kg of water was added to 16 kg of the aqueous solution and mixed well to obtain a slurry. This slurry was fed with a diaphragm pump, and dispersed for 4 hours in a horizontal sand mill (UVM-2: manufactured by Imex Co., Ltd.) filled with zirconia beads having an average diameter of 0.5 mm. 2 g and water were added to prepare a hydrogen bonding compound concentration of 25% by mass. This dispersion was heated at 40 ° C. for 1 hour and then further heated at 80 ° C. for 1 hour to obtain a hydrogen bonding compound-1 dispersion. The hydrogen bonding compound particles contained in the hydrogen bonding compound dispersion thus obtained had a median diameter of 0.45 μm and a maximum particle diameter of 1.3 μm or less. The obtained hydrogen bonding compound dispersion was filtered through a polypropylene filter having a pore size of 3.0 μm to remove foreign substances such as dust and stored.

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

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

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

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

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

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

11) Preparation of Pigment-1 Dispersion C.I. I. Pigment Blue 60 (64 g) and Kao Corp. Demol N (6.4 g) were added to 250 g of water and mixed well to obtain a slurry. Prepare 800 g of zirconia beads having an average diameter of 0.5 mm, put them in a vessel together with the slurry, and disperse with a disperser (1/4 G sand grinder mill: manufactured by IMEX Co., Ltd.) for 25 hours. A pigment-1 dispersion was obtained by adjusting the concentration to 5% by mass. The pigment particles contained in the pigment dispersion thus obtained had an average particle size of 0.21 μm.

12) Preparation of SBR latex solution SBR latex was prepared as follows.
In a polymerization kettle of a gas monomer reactor (TAS-2J type manufactured by Pressure Glass Industrial Co., Ltd.), 287 g of distilled water and a surfactant (Pionin A-43-S (manufactured by Takemoto Yushi Co., Ltd.)): solid content 48.5 (Mass%) 7.73 g, 1 mol / liter NaOH 14.06 ml, ethylenediaminetetraacetic acid tetrasodium salt 0.15 g, styrene 255 g, acrylic acid 11.25 g, tert-dodecyl mercaptan 3.0 g were put, the reaction vessel was sealed and the stirring speed was Stir at 200 rpm. After degassing with a vacuum pump and repeating nitrogen gas replacement several times, 108.75 g of 1,3-butadiene was injected and the internal temperature was raised to 60 ° C. A solution obtained by dissolving 1.875 g of ammonium persulfate in 50 ml of water was added thereto, and the mixture was stirred as it was for 5 hours.
The temperature was further raised to 90 ° C. and stirred for 3 hours. After the reaction was completed, the internal temperature was lowered to room temperature, and then Na ⁺ ion: NH ₄ ⁺ ion = 1: 1 using 1 mol / liter NaOH and NH ₄ OH. Addition treatment was performed so that the molar ratio was 5.3 (molar ratio), and the pH was adjusted to 8.4. Thereafter, the mixture was filtered through a polypropylene filter having a pore size of 1.0 μm to remove foreign substances such as dust and stored to obtain 774.7 g of SBR latex. When the halogen ions were measured by ion chromatography, the chloride ion concentration was 3 ppm. As a result of measuring the concentration of the chelating agent by high performance liquid chromatography, it was 145 ppm.

  The latex has an average particle size of 90 nm, Tg = 17 ° C., solid content concentration of 44 mass%, equilibrium moisture content at 25 ° C. and 60% RH, 0.6 mass%, ion conductivity of 4.80 mS / cm (measurement of ion conductivity is A latex stock solution (44 mass%) was measured at 25 ° C. using a conductivity meter CM-30S manufactured by Toa Denpa Kogyo Co., Ltd.).

2. Preparation of coating solution 1) Preparation of coating solution for image forming layer 1000 g of fatty acid silver dispersion obtained above, water, pigment-1 dispersion, organic polyhalogen compound-1 dispersion, organic polyhalogen compound-2 dispersion, phthalazine Compound-1 solution, SBR latex (Tg: 17 ° C.) liquid, present invention and comparative reducing agent dispersion (type and addition amount are shown in Table 1), hydrogen bonding compound-1 dispersion, development accelerator 1 Dispersion, Development Accelerator-2 Dispersion, Coloring Agent Dispersion (type and addition amount are shown in Table 1. Addition amount is mol% with respect to the reducing agent), and mercapto compound-2 aqueous solution are added in order. Immediately before coating, the silver halide mixed emulsion A was added and mixed well, and the image forming layer coating solution was directly fed to the coating die for coating. The amounts of these materials added were adjusted to the amounts shown in Table 1 and described later.

The viscosity of the image forming layer coating solution 101 was 40 [mPa · s] at 40 ° C. (No. 1 rotor, 60 rpm) as measured with a B-type viscometer of Tokyo Keiki.
The viscosity of the coating solution at 38 ° C. using a Haake RheoStress RS150 is 30, 43, 41, 28, 20 [mPa · s] at shear rates of 0.1, 1, 10, 100, 1000 [1 / second], respectively. s].

  The amount of zirconium in the coating solution was 0.30 mg per 1 g of silver.

3) Preparation of intermediate layer coating solution 1000 g of polyvinyl alcohol PVA-205 (manufactured by Kuraray Co., Ltd.), 163 g of pigment-1 dispersion, blue dye compound-1 (manufactured by Nippon Kayaku Co., Ltd .: Kayafect Turquoise RN Liquid 150 ) 33 g of aqueous solution, 27 ml of 5% aqueous solution of di (2-ethylhexyl) sodium sulfosuccinate, methyl methacrylate / styrene / butyl acrylate / hydroxyethyl methacrylate / acrylic acid copolymer (copolymer weight ratio 57/8/28/5/2) ) 27 ml of a 5% by weight aqueous solution of aerosol OT (manufactured by American Cyanamid Co., Ltd.) was added to 4200 ml of a 19% by weight latex, 135 ml of a 20% by weight aqueous solution of diammonium phthalate, and water was added to a total amount of 10,000 g. Adjust to pH 7.5 with NaOH The layer coating solution was fed to the coating die so as to be 8.9 ml / m ² .
The viscosity of the coating solution was 58 [mPa · s] at a B-type viscometer of 40 ° C. (No. 1 rotor, 60 rpm).

4) Preparation of surface protective layer first layer coating solution 100 g of inert gelatin and 10 mg of benzoisothiazolinone were dissolved in 840 ml of water, and a methyl methacrylate / styrene / butyl acrylate / hydroxyethyl methacrylate / acrylic acid copolymer (copolymerization weight ratio). 57/8/28/5/2) Latex 19% by weight solution 180g, phthalic acid 15% by weight methanol solution 46ml, sulfosuccinic acid di (2-ethylhexyl) sodium salt 5% by weight aqueous solution 5.4ml was added. The mixture was mixed, and immediately before coating, 40 ml of 4% by weight chromium alum was mixed with a static mixer and fed to the coating die so that the amount of the coating solution was 26.1 ml / m ² .
The viscosity of the coating solution was 20 [mPa · s] at a B-type viscometer of 40 ° C. (No. 1 rotor, 60 rpm).

5) Preparation of surface protective layer second layer coating solution 100 g of inert gelatin and 10 mg of benzoisothiazolinone are dissolved in 800 ml of water and 8.0 g of liquid paraffin emulsion as liquid paraffin, methyl methacrylate / styrene / butyl acrylate / hydroxyethyl Methacrylate / acrylic acid copolymer (copolymerization weight ratio 57/8/28/5/2) Latex 19% by weight solution 180g, phthalic acid 15% by weight methanol solution 40ml, Fluorosurfactant (F-1) 1 5.5 ml of mass% solution, 5.5 ml of 1 mass% aqueous solution of fluorosurfactant (F-2), 28 ml of 5 mass% aqueous solution of di (2-ethylhexyl) sodium sulfosuccinate, polymethyl methacrylate fine particles (Average particle size 0.7 μm) 4 g, polymethyl methacrylate fine particles (average particle size) A mixture of 4.5 [mu] m) 21g and the surface protective layer coating solution was fed to a coating die so that 8.3 ml / m ^2.
The viscosity of the coating solution was 19 [mPa · s] at a B-type viscometer of 40 ° C. (No. 1 rotor, 60 rpm).

3. Preparation of photothermographic material Simultaneously multilayer coating by slide bead coating method in the order of image forming layer, intermediate layer, surface protective layer first layer, surface protective layer second layer from the undercoat surface to the surface opposite to the back surface, A sample of the photothermographic material was prepared. At this time, the coating solution for the image forming layer and the intermediate layer was adjusted to 31 ° C., the coating solution for the first surface protective layer was adjusted to 36 ° C., and the coating solution for the second surface protective layer was adjusted to 37 ° C.
The coating amount (g / m ² ) of each compound in the image forming layer is as follows.

Silver behenate 5.42
Pigment (C.I. Pigment Blue 60) 0.036
Polyhalogen compound-1 0.10
Polyhalogen compound-2 0.20
Phthalazine Compound-1 0.18
SBR latex 9.70
Comparative reducing agent or reducing agent of the present invention (described in Table 1)
Color former (described in Table 1)
Hydrogen bonding compound-1 0.58
Development accelerator-2 0.01
Mercapto Compound-1 0.002
Mercapto compound-2 0.012
Silver halide (as Ag) 0.10

The coating and drying conditions are as follows.
The coating was performed at a speed of 160 m / min, the gap between the coating die tip and the support was set to 0.10 mm to 0.30 mm, and the pressure in the decompression chamber was set to be 196 Pa to 882 Pa lower than the atmospheric pressure. The support was neutralized with an ion wind before coating.
In the subsequent chilling zone, after cooling the coating solution with a wind at a dry bulb temperature of 10 to 20 ° C., it is transported in a non-contact type, and is dried at a dry bulb temperature of 23 to 45 ° C. It dried with the dry wind of the wet bulb temperature 15-21 degreeC.
After drying, the humidity was adjusted at 25 ° C. and humidity of 40 to 60% RH, and then the film surface was heated to 70 to 90 ° C. After heating, the film surface was cooled to 25 ° C.
The photothermographic material thus prepared had a Beck smoothness of 550 seconds on the photosensitive layer surface side and 130 seconds on the back surface. Further, the pH of the film surface on the photosensitive layer surface side was measured and found to be 6.0.

  The chemical structures of the compounds used in the examples of the present invention are shown below.

4). Evaluation of photographic performance 1) Preparation The obtained samples were cut into half-cut sizes, packaged in the following packaging materials in an environment of 25 ° C. and 50% RH, stored at room temperature for 2 weeks, and then evaluated as follows. .
(Packaging material)
PET 10 μm / PE 12 μm / aluminum foil 9 μm / Ny 15 μm / polyethylene 50 μm containing 3% by mass of carbon:
Oxygen permeability: 0.02 ml / atm · m ² · 25 ° C · day;
Moisture permeability: 0.10 g / atm · m ² · 25 ° C · day.

2) Exposure / development of photosensitive material Each sample was exposed with Fuji Medical Dry Laser Imager FM-DPL (mounted with a 660 nm semiconductor laser with a maximum output of 60 mW (IIIB)) and thermally developed (112 ° C.-119 ° C.-121 ° C.). 4 panel heaters set at −121 ° C. for a total of 24 seconds).
The obtained image was evaluated with a densitometer.

3) Evaluation of photographic performance (Sensitivity) The sensitivity is the logarithm of the reciprocal of the exposure amount giving a density of 1.0, and the difference is shown when the sample 101 is used as a reference.
(Image storability) The sample after processing was shown as an increase in fog density (ΔDmin) when irradiated with light for 24 hours with a Shakasten (about 4000 Lux) placed in an environment of 30 ° C.-65% RH.
(Silver tone) Sensory evaluation was made visually.
The obtained results are shown in Table 1.

  The samples of the present invention showed good image storage stability, and in particular, Samples 112 to 120 showed high sensitivity and favorable silver tone. Among them, the color formers used for Samples 115, 116, 119, and 120 were preferable because they could provide a good color tone with a small addition amount.

Example 2
1. Preparation of photothermographic material (Preparation of image forming layer coating solution)
1000 g of fatty acid silver dispersion B (the preparation method is shown below), water 1, pigment-1 dispersion, organic polyhalogen compound-1 dispersion, organic polyhalogen compound-2 dispersion, phthalazine compound-1 solution, SBR latex (Tg: 17 ° C.) liquid, the present invention and comparative reducing agent dispersion (type and amount added are shown in Table 2), color former dispersion (type and amount added are shown in Table 2. The added amount is reduced. The hydrogen bonding compound-1 dispersion, the development accelerator-1 dispersion, the development accelerator-2 dispersion, and the mercapto compound-2 aqueous solution were sequentially added, and the silver halide was applied just before coating. The image forming layer coating solution, to which the mixed emulsion A was added and well mixed, was fed to the coating die as it was and coated. The amounts of these materials added were adjusted to the amounts shown in Table 2 and described later.
The viscosity of the image forming layer coating solution 201 was 40 [mPa · s] at 40 ° C. (No. 1 rotor, 60 rpm) as measured with a B-type viscometer of Tokyo Keiki.
The viscosity of the coating solution at 38 ° C. using a Haake RheoStress RS150 is 30, 43, 41, 28, 20 [mPa · s] at shear rates of 0.1, 1, 10, 100, 1000 [1 / second], respectively. s].

  The amount of zirconium in the coating solution was 0.30 mg per 1 g of silver.

(Preparation of fatty acid silver dispersion B)
1) Preparation of recrystallized behenic acid 100 kg of Henkel behenic acid (product name Edenor C22-85R) was mixed in 1200 kg of isopropyl alcohol, dissolved at 50 ° C., filtered through a 10 μm filter, and then cooled to 30 ° C. And recrystallized. The cooling speed during recrystallization was controlled at 3 ° C./hour. The obtained crystals were centrifugally filtered, washed with 100 kg of isopropyl alcohol, and then dried. When the obtained crystals were esterified and subjected to GC-FID measurement, the behenic acid content was 96 mol%, and in addition, lignoceric acid was 2 mol%, arachidic acid was 2 mol%, and erucic acid was 0.001 mol%. It was.

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

After completion of the addition of the sodium behenate solution B, the mixture was left stirring for 20 minutes at the same temperature, heated to 35 ° C. over 30 minutes, and then aged for 210 minutes. Immediately after completion of aging, the solid content was separated by centrifugal filtration, and the solid content was washed with water until the conductivity of filtered water reached 30 μS / cm. Thus, a fatty acid silver salt was obtained. The obtained solid content was stored as a wet cake without drying.
When the morphology of the obtained silver behenate particles was evaluated by electron microscope photography, the average values were a = 0.21 μm, b = 0.4 μm, c = 0.4 μm, average aspect ratio 2.1, and equivalent sphere diameter. The crystal had a coefficient of variation of 11%. (A, b, and c are the text provisions)

  19.3 kg of polyvinyl alcohol (trade name: PVA-217) and water are added to a wet cake corresponding to a dry solid content of 260 kg to make a total amount of 1000 kg, and then slurried with a dissolver blade. : PM-10 type).

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

(Application)
In the same manner as in Example 1, only the image forming layer coating solution was changed and applied.
The coating amount (g / m ² ) of each compound in the image forming layer is as follows.

Silver behenate 5.27
Pigment (C.I. Pigment Blue 60) 0.036
Polyhalogen compound-1 0.12
Polyhalogen compound-2 0.25
Phthalazine Compound-1 0.18
SBR latex 9.43
Comparative reducing agent or reducing agent of the present invention (described in Table 2)
Color former (described in Table 2)
Hydrogen bonding compound-1 0.28
Development accelerator-1 0.015
Development accelerator-2 0.020
Mercapto compound-2 0.003
Silver halide (as Ag) 0.13

2. Performance evaluation (exposure, heat development)
Each panel was exposed with Fuji Medical Co., Ltd. dry laser imager DRYPIX7000 (mounted with a 660 nm semiconductor laser with a maximum output of 50 mW (IIIB)) and heat developed (three panel heaters set at 107 ° C-121 ° C-121 ° C) For a total of 14 seconds).
In addition to the evaluation of the evaluation items similar to those in Example 1, the following evaluation was added.
(Hue angle) This is an angle obtained from the a ^* b ^* coordinates of the CIE standard defined in the JIS Z8729 standard at a density of 1.0.
The medical sensitive material is preferably in the range of 180 ° to 270 °, more preferably in the range of 210 ° to 260 °.
(Hue change) Each developed sample was visually sensory evaluated for silver tone change immediately after thermal development when left for 1 day in a Schaukasten (about 4000 Lux) placed in an environment of 30 ° C. and 65% RH. ○ indicates that the change is hardly understood, Δ indicates a slight change that is within the allowable range, and × indicates that the change is clearly recognized and cannot be allowed.

The obtained results are shown in Table 2.
All of the samples of the present invention showed good performance, but particularly the sample using the color former showed more favorable hue angle and little change in color tone, and showed good results.

Claims (10)

A photothermographic material containing a photosensitive silver halide, a non-photosensitive organic silver salt, a reducing agent and a binder on the same surface of a support, wherein at least one of the reducing agents is represented by the following general formula (R1): A photothermographic material characterized in that it is a compound represented by:
Formula (R1)

@ 0048

(In the formula, R ¹ and R ¹ ′ each independently represent an alkyl group having 1 to 20 carbon atoms. R ² and R ² ′ each independently represent a hydrogen atom or a substituent that can be substituted on a benzene ring. R ³ represents a substituent which forms a ring composed of atoms selected from 3 to 7-membered carbon atoms, oxygen atoms, nitrogen atoms, sulfur atoms and phosphorus atoms, X and X ′ are each independently a hydrogen atom or benzene Represents a substitutable group on the ring).   2. The photothermographic material according to claim 1, further comprising a color former capable of developing color by heat development.   3. The photothermographic material according to claim 2, wherein the color former is a compound capable of forming a dye having main absorption in a wavelength region of 350 nm to 500 nm or 600 nm to 700 nm.   4. The photothermographic material according to claim 2, wherein the color former is a compound that forms a yellow dye having main absorption in a wavelength region of 350 nm to 500 nm. The photothermographic material according to claim 2, wherein the color former is a compound represented by the following general formula C:
General formula (C)

@ 0049

(General formula (C) in R ₁ and R ₂ are each independently a halogen atom, an alkyl group, an alkoxy group, an amino group, an acylamino group, an acyloxy group, an acyl group, an alkoxycarbonyl group or a carbamoyl group, R ₃ and R ₄ each independently represents a hydrogen atom, a halogen atom, a hydroxyl group, an amino group, an alkoxy group, an acyloxy group, an acylamino group, an aryl group or a heterocyclic group. In the reducing agent represented by the general formula (R1), to one of the claims 1 to 5, wherein at least one of R ¹ or R ^{1 'is} secondary or tertiary alkyl group The photothermographic material according to the description.   7. The photothermographic material according to claim 1, wherein a hue angle at an image density of 1.0 is in a range of 180 [deg.] To 270 [deg.]. The photothermographic material according to any one of claims 1 to 7, Gin'nuri設量is characterized in that in the range of ^{0.8g / m 2 ~1.9g / m 2} .   9. The photothermographic material according to claim 1, wherein the heat development time is in the range of 6 seconds to 14 seconds.   10. The photothermographic material according to claim 1, wherein the ratio of developed silver in the highest image density portion is 85% or more based on the total coated silver amount.