JP2003098618A - Heat-developable photosensitive material and imaging method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat-developable photosensitive material giving an image having good preservability and a good color tone (closer to a pure black tone) even when infrared-sensitized and to provide an imaging method using the material. SOLUTION: In the heat-developable photosensitive material comprising at least photosensitive silver halide, a non-photosensitive organic silver salt, a reducer for silver ions and a binder on one face of a support, the silver behenate content of the non-photosensitive organic silver salt is 53-80 mol.%, at least one of the polyphenol compounds of formula (1) is contained as the reducer and the photosensitive silver halide has been infrared-sensitized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photothermographic material, particularly for medical diagnosis, industrial photography, printing and COM.
As to a photothermographic material suitable for use as an image forming method and an image forming method using the same, in particular, an infrared sensitized photothermographic material and an image using the same which are preferably used for medical images or photolithography. It relates to a forming method.

[0002]

2. Description of the Related Art In recent years, in the fields of medical diagnostic films and photoengraving films, there has been a strong demand for reducing the amount of processing waste liquid from the viewpoint of environmental protection and space saving. Therefore, heat development as a film for medical diagnosis and a film for photoengraving, which can be efficiently exposed by a laser imagesetter or a laser imager and can form a clear black image having high resolution and sharpness. There is a need for technology related to photosensitive materials. According to these photothermographic materials, it is possible to provide the customer with a photothermographic processing system that does not require solution-type processing chemicals and is simpler and does not damage the environment.

Although there are similar demands in the field of general image forming materials, particularly medical diagnostic images require fine depiction, so high image quality excellent in sharpness and graininess is required, and diagnostic images are required. There is a feature that a cold black image is preferred from the viewpoint of easiness. At present, various hard copy systems using pigments and dyes such as inkjet printers and electrophotography are in circulation as general image forming systems, but none are satisfactory as output systems for medical images.

On the other hand, thermal image forming systems utilizing organic silver salts are disclosed in, for example, US Pat. Nos. 3,152,904 and 345.
7075 and D.I. Cross Tabor (Kl
Osterboer, “Thermal Processed Sil.
Ver. System ”(Imaging Processes and Materials (Imaging Pro)
cesses and Materials) Nebl
8th edition, J. et. Sturge, V.I.
Wallworth, A.S. Editing by Shepp, Chapter 9, p. 279, 1989.
Year). 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, organic silver salt), and if necessary, a toning agent for controlling the color tone of silver. , Having a photosensitive layer dispersed in a binder matrix.

The photothermographic material is heated to a high temperature (for example, 80 ° C. or higher) after imagewise exposure, and undergoes a redox reaction between a reducible silver salt (which functions as an oxidizing agent) and a reducing agent.
Form a black silver image. The redox 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 exposed area. It is disclosed in many documents including U.S. Pat. No. 2,910,377 and Japanese Patent Publication No. 43-4924.

In the photothermographic material, it is preferable that the redox reaction between the reducible silver salt and the reducing agent proceeds at a realistic reaction temperature and reaction time so that a sufficient image density can be obtained. At present, there is a demand for further development of a photothermographic material having high development activity, rapid reaction, and low fog.

Further, since the photothermographic material using the organic silver salt does not fix the organic silver salt or the like, a silver image may appear due to light / heat after the silver image is formed by heat. have. In the normal use range, of course, such a thing does not occur, but it is very harsh for the photothermographic material, for example, when the processed film is placed in a car in the summer for the purpose of transportation or the like. When stored under the conditions, there is a problem that discoloration of the entire film or transfer of characters on the bag in which the film is stored onto the film, that is, fog occurs.

Laser light is used as an exposure light source in a thermal image forming system using an organic silver salt which has been used in a medical image output system due to recent technological innovation and digitalization. In addition, the type of laser light used is generally a semiconductor laser having an infrared wavelength because laser power can be obtained at low cost.

By the way, a pure black tone is desired for medical diagnostic images, and it is difficult to produce a pure black tone with a thermal image forming system using this organic silver salt. Although the color tone is adjusted, the color tone control is not sufficient and improvement is desired. Further, in the above infrared-sensitized photothermographic material, a heteroaromatic mercapto compound or a heteroaromatic disulfide compound is used as a strong sensitizer to enhance the sensitization. The disulfide compound increases the sensitivity when the amount added is increased, but there is a problem that it is difficult to obtain a pure black tone because the image tone changes, and improvement is desired.

[0010]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the various problems in the prior art and achieve the following objects. That is, the object of the present invention, even if infrared sensitized,
An object of the present invention is to provide a photothermographic material capable of obtaining an image having good image storability and a good color tone (close to a pure black tone), and an image forming method using the same.

[0011]

Means for Solving the Problems As a result of intensive studies for solving the above problems, the present inventors have found that the following means can be achieved. That is, the present invention relates to <1> one surface of a support, on which at least a photosensitive silver halide, a non-photosensitive organic silver salt, a reducing agent for silver ions,
In a photothermographic material containing a binder, the content of silver behenate in the non-photosensitive organic silver salt is 53 mol% or more and 80 mol% or less, and the reducing agent is represented by the following general formula (1). A photothermographic material containing at least one polyphenol compound according to claim 1, wherein the photosensitive silver halide is infrared-sensitized.

[0012]

[Chemical 3]

(In the general formula (1), R ¹¹ and R ^{11 '}
Each independently represents a substituted or unsubstituted C1-20
Represents an alkyl group. R ¹² and R ^{12 ′} are each independently
It represents a hydrogen atom or a group capable of substituting for a benzene ring. 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. X ¹
And X ^{1 ′} each independently represent a hydrogen atom or a group capable of substituting for a benzene ring. )

<2> In the compound represented by the general formula (1), R ¹¹ and R ^{11 ′} each independently have 3 to 8 carbon atoms.
Is a secondary or tertiary alkyl group of R ¹² and R ^{12 ′}
Are each independently an alkyl group, L is a —CHR ¹³ — group (wherein R ¹³ is a hydrogen atom or an alkyl group having 1 to 12 carbon atoms), and X ¹ and X ^{1 ′} are hydrogen atoms. The photothermographic material according to <1> above.

<3> In the compound represented by the general formula (1), R ¹¹ , R ^{11 ′} , R ¹² and R ^{12 ′} are methyl groups, and L is a —CHR ¹³ — group (here, R ¹³ Has 3 to 1 carbon atoms
2 is a secondary alkyl group. ) And X ¹ and X ^{1 ′} are hydrogen atoms, and the photothermographic material according to <1> above.

<4> At least one hindered phenol compound represented by the following general formula (2) is contained on the same surface of the support containing the photosensitive silver halide, and the following general formula ( The ratio of the amount of the compound represented by 2) to the compound represented by the general formula (1) (general formula (2)
In any one of the above items <1> to <3>, the compound (mole) represented by the formula / the compound (mole) represented by the general formula (1) is 0.001 to 0.2. The photothermographic material described.

[0017]

[Chemical 4]

(In the general formula (2), R ²¹ and R
Each ²² independently represents a hydrogen atom, an alkyl group or an acylamino group. However, R ²¹ and R ²² are each 2
It is neither a -hydroxyphenylmethyl group nor a hydrogen atom at the same time. R ²³ represents a hydrogen atom or an alkyl group. R ²⁴ represents a substituent capable of substituting on the benzene ring. )

<5> The silver behenate content of the non-photosensitive organic silver salt is 55 mol% or more and 75 mol% or less, according to any one of the above items <1> to <4>. Photothermographic material.

<6> The photothermographic material according to any one of <1> to <5>, wherein the non-photosensitive organic silver salt is dried in an atmosphere having an oxygen partial pressure of 15 vol% or less. material.

<7> The photosensitive silver halide, the non-photosensitive organic silver salt, the reducing agent for the silver ions, and the binder are contained in the photosensitive layer. <1> To <6>, which is the photothermographic material.

<8> As the binder, polyvinyl butyral is used in an amount of 5 relative to the total binder composition of the photosensitive layer.
The photothermographic material according to the item <7>, which contains 0% by weight or more and 100% by weight or less.

<9> At least one selected from a heteroaromatic mercapto compound and a heteroaromatic disulfide compound is contained on the same surface of the support containing the photosensitive silver halide as described above. 1> ~
The photothermographic material according to any one of <8>.

<10> An image forming method characterized in that the photothermographic material according to any one of <1> to <9> is exposed to a laser beam having an exposure wavelength of 750 nm to 1400 nm to perform thermal development. Is.

<11> The image forming method according to <10>, wherein the heat development is performed using a heat drum.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a method for carrying out the present invention and an embodiment will be described in detail. The photothermographic material of the present invention comprises, on one surface of a support, at least a photosensitive silver halide, a non-photosensitive organic silver salt, a reducing agent for silver ions, and a binder. The photosensitive organic silver salt has a silver behenate content of 53 mol% to 80 mol%, and contains at least one polyphenol compound represented by the following general formula (1) as the reducing agent, The silver halide is characterized by being infrared sensitized.
The photothermographic material of the present invention having such characteristics is
Even with infrared sensitization, an image having good image storability and good color tone (close to pure black tone) can be obtained.

First, the polyphenol compound represented by the general formula (1) as a reducing agent will be described.

[0028]

[Chemical 5]

In the general formula (1), 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. Preferred examples include an aryl group, a hydroxy group, 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 and a halogen atom. To be

In the general formula (1), R ¹² and R ^{12 ′} each independently represent a hydrogen atom or a substituent capable of substituting on the benzene ring, and X ¹ and X ^{1 ′} also each independently represent a hydrogen atom, Alternatively, it represents a group capable of substituting on the benzene ring. Preferable examples of the group capable of substituting on the benzene ring include an alkyl group, an aryl group, a halogen atom, an alkoxy group, and an acylamino group.

L represents a --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 for 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,
Preferable examples include 2,4,4-trimethylpentyl group and the like. Examples of the substituent of the alkyl group are the same as the substituents of R ¹¹ , and are a halogen atom, an alkoxy group, an alkylthio group, an aryloxy group, an arylthio group, an acylamino group, a sulfonamide group, a sulfonyl group, a phosphoryl group, an oxy group. A carbonyl group, a carbamoyl group, a sulfamoyl group and the like are preferable.

In the general formula (1), R ¹¹ and R ^{11 ′} are preferably a secondary or tertiary alkyl group having 3 to 15 carbon atoms, specifically, isopropyl group, isobutyl group, t
-Butyl group, t-amyl group, t-octyl group, cyclohexyl group, cyclopentyl group, 1-methylcyclohexyl group, 1-methylcyclopropyl group and the like are preferable. As R ¹¹ and R ^{11 ′} , a secondary or tertiary alkyl group having 3 to 8 carbon atoms is more preferable, and among them, a t-butyl group, a t-amyl group and a 1-methylcyclohexyl group are further preferable, and t Most preferred is the -butyl group.

In the general formula (1), R ¹² and R ^{12 ′} are preferably an alkyl group, more preferably an alkyl group having 1 to 20 carbon atoms, specifically, methyl group, ethyl group, propyl group, butyl group. Group, isopropyl group, t-butyl group,
Suitable examples thereof include t-amyl group, cyclohexyl group, 1-methylcyclohexyl group, benzyl group, methoxymethyl group, methoxyethyl group, and the like, and more preferably methyl group, ethyl group, propyl group, isopropyl group, t -Butyl group is mentioned.

In the general formula (1), X ¹ and X ^{1 ′} are
A hydrogen atom, a halogen atom and an alkyl group are preferable, and a hydrogen atom is more preferable.

In the general formula (1), L is --CHR ¹³
-Groups are preferred. R ¹³ is a hydrogen atom or 1 carbon atom
The alkyl group having 15 to 15 carbon atoms is preferable, and the secondary alkyl group having 1 to 12 carbon atoms is more preferable. As the alkyl group,
Methyl group, ethyl group, propyl group, isopropyl group,
A 2,4,4-trimethylpentyl group is preferred. Particularly preferable R ¹³ is a hydrogen atom, a methyl group,
A propyl group or an isopropyl group.

In the general formula (1), 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 an ethyl group. Most preferred are groups. When R ¹³ is a primary or secondary alkyl group having 1 to 12 carbon atoms, R ¹² and R
^{12 '} is preferably a methyl group. R ¹³ has 1 to 1 carbon atoms
As the primary or secondary alkyl group of 2, a methyl group, an ethyl group, a propyl group or an isopropyl group is more preferable,
A methyl group, an ethyl group and a propyl group are more preferable. R
^11, when R ^{11 'R 12} and R ^12' are both methyl groups, as the R ^13, secondary alkyl groups, and more preferably secondary alkyl group having 3 to 12 carbon atoms. In this case, the secondary alkyl group for R ¹³ is preferably an isopropyl group, an isobutyl group or a 1-ethylpentyl group, and particularly preferably an isopropyl group.

As the compound represented by the general formula (1),
R ¹¹ and R ^{11 ′} are each independently a secondary or tertiary alkyl group having 3 to 8 carbon atoms, R ¹² and R ^{12 ′} are each independently an alkyl group, and L is a —CHR ¹³ — group. (R ¹³ is a hydrogen atom or an alkyl group having 1 to 12 carbon atoms (preferably 1 to 7 carbon atoms)), and X ¹ and X ^{1 ′} are hydrogen atoms, and R ¹¹ and R ^{11 ′} , R ¹² and R ^{12 ′} are methyl groups, L is a —CHR ¹³ — group, R ¹³ is a secondary alkyl group having 3 to 12 carbon atoms, and X ¹ and X ^{1 ′} are hydrogen. Those that are atoms are particularly preferred.

Specific examples of the polyphenol compounds represented by the general formula (1) which are reducing agents (exemplary compounds 1-1 to 1-1)
20), but the present invention is not limited thereto.

[0039]

[Chemical 6]

[0040]

[Chemical 7]

[0041]

[Chemical 8]

The addition amount of the polyphenol compound represented by the general formula (1) may be preferably a 0.01~5.0g / m ^2, is 0.1 to 3.0 g / m ² More preferably, it is 5 to 50 mol%, and more preferably 10 to 40 mol% with respect to 1 mol of silver on the side of the support having the photosensitive layer (image forming layer). The polyphenol compound represented by the general formula (1) as the reducing agent is preferably contained in the photosensitive layer (image forming layer).

The heat-developable recording material of the present invention preferably contains a compound (hindered phenol compound) represented by the general formula (2) on the same surface of the support containing the photosensitive silver halide. Hereinafter, the compound represented by formula (2) will be described.

[0044]

[Chemical 9]

In the general formula (2), R ²¹ and R ²² each independently represent a hydrogen atom, an alkyl group or an acylamino group. However, R ²¹ and R ²² are not a 2-hydroxyphenylmethyl group, and are not hydrogen atoms at the same time. R ²³ represents a hydrogen atom or an alkyl group. R ²⁴ represents a substituent capable of substituting on the benzene ring.

In the general formula (2), when R ²¹ is an alkyl group, an alkyl group having 1 to 30 carbon atoms is preferable, and an alkyl group having 1 to 10 carbon atoms is more preferable. The alkyl group is
It may have a substituent. Specific examples of the unsubstituted alkyl group include methyl, ethyl, butyl, octyl, isopropyl, t-butyl, t-octyl, t-amyl,
A sec-butyl group, a cyclohexyl group, a 1-methyl-cyclohexyl group and the like are preferable, and a group that is sterically larger than an isopropyl group (for example, isopropyl group, isononyl group, t-butyl group, t-amyl group, t-octyl group, cyclohexyl group). Group, 1-methyl-cyclohexyl group, adamantyl group, etc.), among which tertiary alkyl groups t-butyl, t-octyl, t
-Amyl group and the like are particularly preferable. Further, when the alkyl group has a substituent, the substituent is a halogen atom, an aryl group, an alkoxy group, an amino group, an acyl group,
Examples thereof include an acylamino group, an alkylthio group, an arylthio group, a sulfonamide group, an acyloxy group, an oxycarbonyl group, a carbamoyl group, a sulfamoyl group, a sulfonyl group and a phosphoryl group.

In the general formula (2), when R ²² is an alkyl group, an alkyl group having 1 to 30 carbon atoms is preferable, and an unsubstituted alkyl group having 1 to 24 carbon atoms is more preferable. The alkyl group may have a substituent. Specific examples of the unsubstituted alkyl group are methyl, ethyl, butyl, octyl, isopropyl, t-butyl, t-octyl, t-amyl, sec-butyl, cyclohexyl and 1-methyl-cyclohexyl groups. Examples of substituents are
Same as R ²¹ .

In the general formula (2), when R ²¹ and R ²² are acylamino groups, an acylamino group having 1 to 30 carbon atoms is preferable, and an acylamino group having 1 to 10 carbon atoms is more preferable. The acylamino group may be unsubstituted or may have a substituent. Specific examples include an acetylamino group, an alkoxyacetylamino group, an aryloxyacetylamino group and the like.

In the general formula (2), R ²¹ is preferably a hydrogen atom, an alkyl group or an acylamino group, and an alkyl group. On the other hand, R ²² is preferably a hydrogen atom or an unsubstituted alkyl group having 1 to 24 carbon atoms among a hydrogen atom, an alkyl group or an acylamino group, and specifically, a methyl group, an isopropyl group, a t-butyl group. In addition,
R ²¹ and R ²² are neither a 2-hydroxyphenylmethyl group nor a hydrogen atom at the same time.

In the general formula (2), R ²³ represents a hydrogen atom or an alkyl group, and among them, a hydrogen atom or an alkyl group having 1 to 30 carbon atoms is preferable, and a hydrogen atom or an unsubstituted C 1 to 24 carbon atom. Is more preferred. The description of the alkyl group is the same as that of R ²² . Specific examples thereof include a methyl group, an isopropyl group, and a t-butyl group.
Either one of R ²² and R ²³ is preferably a hydrogen atom.

In the general formula (2), R ²⁴ represents a group capable of substituting on the benzene ring, and R ¹² and R in the compound of the general formula (1) are represented.
It is the same group as explained in ^{12 '} . As R ²⁴ , a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms and an oxycarbonyl group having 2 to 30 carbon atoms are preferable, and an alkyl group having 1 to 24 carbon atoms is more preferable. As the substituent of the alkyl group, an aryl group, an amino group, an alkoxy group,
Examples thereof include an oxycarbonyl group, an acylamino group, an acyloxy group, an imide group and a ureido group, and an aryl group, an amino group, an oxycarbonyl group and an alkoxy group are more preferable.

A more preferable structure of the compound of the general formula (2) is represented by the following general formula (3).

[0053]

[Chemical 10]

In the general formula (3), R ³¹ , R ³² , R ³³ and R ³⁴ each independently represent a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, and an alkyl group having 1 to 10 carbon atoms. Preferably there is. The substituent of the alkyl group is not particularly limited, but preferably an aryl group, a hydroxy group, an alkoxy group, an aryloxy group, an alkylthio group, an arylthio group, an acylamino group, a sulfonamide group, a sulfonyl group, a phosphoryl group, Examples thereof include an acyl group, a carbamoyl group, an ester group and a halogen atom. Among these, a group that is sterically larger than an isopropyl group (eg, isopropyl group, isononyl group, t-butyl group, t
-Amyl group, t-octyl group, cyclohexyl group, 1-
At least one methyl-cyclohexyl group, adamantyl group, etc.) is preferable, and two or more groups are more preferable. Particularly preferred are tertiary alkyl groups that are sterically larger than isopropyl groups, such as t-butyl, t-octyl, and t-amyl groups. L is the same as L in the compound of general formula (1).

Specific examples of the compound represented by the general formula (2) (including the compound represented by the general formula (3)) in the present invention are shown below, but the invention is not limited thereto.

[0056]

[Chemical 11]

[0057]

[Chemical 12]

[0058]

[Chemical 13]

[0059]

[Chemical 14]

[0060]

[Chemical 15]

[0061]

[Chemical 16]

The compounds represented by the general formulas (1) to (3) may be incorporated into the coating solution by any method such as solution form, emulsified dispersion form and solid fine particle dispersion form, and may be incorporated into the light-sensitive material. . Examples of the emulsification dispersion method include a method in which an oil such as dibutyl phthalate, tricresyl phosphate, glyceryl triacetate or diethyl phthalate, or an auxiliary solvent such as ethyl acetate or cyclohexanone is dissolved to mechanically prepare an emulsion dispersion. To be As the solid fine particle dispersion method, general formulas (1) to (3) are used.
A method of preparing a solid dispersion by dispersing the powder of the compound represented by the above in a suitable solvent such as water by a ball mill, a colloid mill, a vibrating ball mill, a sand mill, a jet mill, a roller mill, or ultrasonic waves. At that time, a protective colloid (for example, polyvinyl alcohol),
A surfactant (for example, an anionic surfactant such as sodium triisopropylnaphthalenesulfonate (a mixture of three different isopropyl group substitution positions)) may be used. The water dispersion may contain a preservative (for example, benzoisothiazolinone sodium salt).

The compounds represented by the general formulas (1) to (3) are preferably contained in an image forming layer containing an organic silver salt, but one of them is an image forming layer and the other is a non-image forming layer. It may be contained in the forming layer, or both may be contained in the non-image forming layer. When the image forming layer is composed of a plurality of layers, they may be contained in separate layers.

Addition ratio of the compound represented by the general formula (1) (polyphenol linked to the o-position) and the compound represented by the general formula (2) (hindered phenol compound) ((in the general formula (2) (Compound represented) (mol) / compound represented by general formula (1) (mol)) is preferably in the range of 0.001 to 0.2, and more preferably in the range of 0.005 to 0.1. It is more preferable that the amount is in the range of 0.008 to 0.05. The same applies to the addition ratio of the compound represented by the general formula (1) and the compound represented by the general formula (3).

Next, a non-photosensitive organic silver salt (hereinafter, simply referred to as an organic silver salt) will be described. Organic silver salts are relatively stable to light, but when heated to 80 ° C. or higher in the presence of an exposed photocatalyst (such as a latent image of photosensitive silver halide) and a reducing agent. It is preferably a silver salt that forms a silver image. The organic silver salt may be any organic substance containing a source capable of reducing silver ions, but the silver behenate may be 53
It is characterized by containing mol% to 80 mol%, and 55 mol% to 7
5 mol% is preferable, 60 mol% to 75 mol%
It is particularly preferable to include. As the silver salt of an organic acid other than that, particularly (having 10 to 30 carbon atoms, preferably 15 to 2 carbon atoms)
Silver salts of 8 long chain fatty carboxylic acids are preferred. The ligand is 4.
Complexes of organic or inorganic silver salts having complex stability constants in the range 0 to 10.0 are also preferred. Regarding such a non-photosensitive organic silver salt, paragraph 0 of JP-A-10-62899 is used.
048-0049, European Patent Publication No. 0803764A1
No. 18, page 24 to page 19, line 37, European Patent Publication No. 0962812A1, JP-A-11-34.
No. 9591, JP-A Nos. 2000-7683, 2000-
No. 72711 and the like. Preferred organic silver salts include silver salts of organic compounds having a carboxyl group. Examples of these include, but are not limited to, silver salts of aliphatic carboxylic acids and silver salts of aromatic carboxylic acids. Preferred examples of the silver salt of an aliphatic carboxylic acid include, in addition to the above-mentioned silver behenate, silver arachidate, silver stearate, silver oleate, silver laurate, silver caproate, silver myristate, and silver palmitate. , Silver maleate, silver fumarate, silver tartrate, silver linoleate, silver butyrate and silver camphorate, mixtures thereof and the like. The organic silver salt as the silver supplying substance can preferably constitute about 5 to 30% by mass of the image forming layer.

The shape of the organic silver salt is not particularly limited,
It may be cubic, rectangular parallelepiped, rod-shaped, needle-shaped, flat-plate-shaped or flaky, but among them, cubic-shaped, rectangular parallelepiped-shaped, rod-shaped or needle-shaped is relatively preferable. Cubic, rectangular parallelepiped, rod-shaped, and needle-shaped organic silver salts are defined as follows. The organic acid silver salt is observed with an electron microscope, the shape of the organic silver salt particles is approximated to a rectangular parallelepiped, and the sides of the rectangular parallelepiped are defined as a, b, and c from the shortest side (a ≦ b).
≤c). Cubic particles mean particles in the range of 0.9 ≦ a / c ≦ 1.0. Rectangular particles mean 0.2 ≦ a / c
Particles in the range of <0.9 and 0.2 ≦ b / c <1.0. Rod-shaped particles mean 0.1 ≦ a / c <0.2 and 0.1
Particles in the range of ≦ b / c <0.3. The acicular particles are particles having a / c <0.1 and b / c <0.1.
The shape of the organic silver salt more preferable in the present invention is acicular or rod-shaped particles, and acicular particles are most preferable.

It is preferable that the particle size of the organic silver salt is small. This is well known in the field of silver halide photographic light-sensitive materials, which is an inversely proportional relationship between the size of silver salt crystal grains and their covering power, and this relationship holds true for the photothermographic material of the present invention. This is because when the organic silver salt particles that are the image forming portion of the photothermographic material are large, the covering power is low and the image density is low. Specifically, the particle size of the organic silver salt has a minor axis of 0.01 μm or more and a value of 0.
20 μm or less, long axis 0.10 μm or more and 5.0 μm or less, short axis 0.01 μm or more and 0.15 μm
More preferably, the length is m or less and the major axis is 0.10 μm or more and 4.0 μm or less. The particle size distribution of the organic silver salt is preferably monodisperse. Monodisperse is 1 of the value obtained by dividing the standard deviation of the lengths of the short axis and long axis by the short axis and long axis respectively.
The 00 fraction is preferably 100% or less, more preferably 8%.
It is 0% or less, more preferably 50% or less.

The shape of the organic silver salt can be measured by a transmission electron microscope image of the organic silver salt dispersion. As another method of measuring the monodispersity, there is a method of obtaining the standard deviation of the volume-weighted average diameter of the organic silver salt, and the 100 fraction (variation coefficient) of the value divided by the volume-loaded average diameter is preferably 100% or less. , More preferably 80% or less, further preferably 50% or less. As a measuring method, for example, the particle size (volume-weighted average diameter) obtained by irradiating an organic silver salt dispersed in a liquid with a laser beam and obtaining an autocorrelation function with respect to the time change of the scattered light fluctuation You can

The organic silver salt is prepared by forming particles in a water solvent, followed by drying and dispersing in a solvent such as MEK. Drying is preferably performed in an air flow type flash jet dryer at an oxygen partial pressure of 15 vol% or less, more preferably 15 vol% or less and 0.01 vol% or more, and further preferably 10 vol% or less and 0.01 vol% or more.

[0070] While the organic silver salt can be used in a desired amount, preferably 0.1-5 g / m ² of silver coating amount, more preferably from 1 to 3 g / m ^2.

Next, the photosensitive silver halide will be described. Methods of forming photosensitive silver halide are well known in the art, eg Research Disclosure 19
No. 17029, June 1978, and U.S. Pat. No. 3,7.
The method described in the specification of No. 00,458 can be used. As a specific method which can be used in the present invention, a method of converting a part of silver of the organic silver salt into a photosensitive silver halide by adding a halogen-containing compound to the prepared organic silver salt, gelatin, Alternatively, a method can be used in which a photosensitive silver halide grain is prepared by adding a silver-providing compound and a halogen-providing compound into another polymer solution and then mixed with an organic silver salt. In the present invention, the latter method can be preferably used.

The grain size of the photosensitive silver halide is preferably small for the purpose of suppressing white turbidity after image formation, and specifically, it is 0.0001 μm or more and 0.15 μm.
Or less, more preferably 0.02 μm or more and 0.10 μm
The following is good. If the size of the photosensitive silver halide grains is too small, the sensitivity may be insufficient, and if the size is too large, the haze of the light-sensitive material may increase. The term "grain size" as used herein means the length of the edges of silver halide grains when the silver halide grains are cubic or octahedral so-called normal crystals. Further, when the silver halide grains are tabular grains, it means the diameter when converted into a circular image having the same area as the projected area of the main surface. In the case of other non-normal crystals, for example, in the case of spherical grains, rod-shaped grains, etc., it means the diameter when considering a sphere equivalent to the volume of silver halide grains.

Examples of the shape of the photosensitive silver halide grains include cubic, octahedral, tabular grains, spherical grains, rod-shaped grains and potato-shaped grains. In the present invention, cubic grains and tabular grains are particularly preferable. Particles are preferred. When tabular silver halide grains are used, the average aspect ratio is preferably 100: 1 to 2: 1, more preferably 50: 1.
~ 3: 1 is good. Further, grains having 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 {100} plane, which has high spectral sensitization efficiency when a spectral sensitizing dye is adsorbed, may be high. preferable. The ratio is preferably 50% or more, more preferably 65% or more, still more preferably 80% or more. The ratio of the Miller index {100} plane is measured by T.M., which utilizes the adsorption dependence of the {111} plane and the {100} plane in the adsorption of the sensitizing dye. Tani; J. Imaging Sc
i. , 29, 165 (1985). The halogen composition of the photosensitive silver halide is not particularly limited, and may be any of silver chloride, silver chlorobromide, silver bromide, silver iodobromide, silver iodochlorobromide, and silver iodide, In the present invention, silver bromide or silver iodobromide can be preferably used. Silver iodobromide is particularly preferred, and the silver iodide content is preferably 0.1 mol% or more and 40 mol% or less, more preferably 0.1 mol% or more and 20 mol% or less. The distribution of the halogen composition in the grain may be uniform, the halogen composition may be changed stepwise, or the halogen composition may be continuously changed, but a preferable example is the silver iodide content in the grain. High silver iodobromide grains can be used. Further, preferably, silver halide grains having a core / shell structure can be used. The structure is preferably 2
Core / shell particles having a .about.5-fold structure, more preferably a 2-fold to 4-fold structure, can be used.

The photosensitive silver halide grains preferably contain at least one metal complex selected from rhodium, rhenium, ruthenium, osmium, iridium, cobalt, mercury or iron. One kind of these metal complexes may be used, or two or more kinds of the same metal complex and different metal complexes may be used in combination. The preferred content is in the range of 1 nanomol (nmol) to 10 mmol (mmol), and more preferably in the range of 10 nanomol (nmol) to 100 micromol (μmol), relative to 1 mol of silver. As a specific structure of the metal complex, a metal complex having a structure described in JP-A-7-225449 can be used.
A hexacyano metal complex can be preferably used as the compound of cobalt or iron. Specific examples thereof include, but are not limited to, ferricyanate ion, ferrocyanate ion, and hexacyanocobaltate ion. The metal complex-containing phase in the silver halide may be uniform, may be contained in the core portion at a high concentration, or may be contained in the shell portion at a high concentration, and is not particularly limited.

The photosensitive silver halide grains can be desalted by washing with a method known in the art such as a noodle method and a flocculation method. In the present invention, it may or may not be desalted. Good

The photosensitive silver halide grains are preferably chemically sensitized. As a preferable chemical sensitization method, a sulfur sensitization method, a selenium sensitization method, or a tellurium sensitization method can be used as well known in the art. Further, a noble metal sensitization method such as a gold compound, platinum, palladium, or iridium compound or a reduction sensitization method can be used. Known compounds can be used as the compounds preferably used in the sulfur sensitization method, the selenium sensitization method, and the tellurium sensitization method, and the compounds described in JP-A No. 7-128768 can be used.

The amount of the photosensitive silver halide used 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 with respect to 1 mol of the organic silver salt.
It is more preferably not more than mol, particularly preferably not less than 0.03 mol and not more than 0.25 mol. Regarding the mixing method and mixing conditions of the separately prepared photosensitive silver halide and the organic silver salt, the prepared silver halide grains and the organic silver salt are mixed with a high-speed stirrer, a ball mill, a sand mill, a colloid mill, a vibration mill, a homogenizer, etc. Or a method of preparing an organic silver salt by mixing the photosensitive silver halide prepared at any timing during the preparation of the organic silver salt, but the effect of the present invention is sufficient. There is no particular limitation as long as it appears.

As a method for preparing silver halide, a so-called halide method in which a part of silver of an organic silver salt is halogenated with an organic or inorganic halide is also preferably used. The organic halide used here may be any compound as long as it is a compound that reacts with an organic silver salt to form a silver halide, and may be N-halogenoimide (N-bromosuccinimide or the like), halogenated quaternary nitrogen compound (odorous). And tetrabutylammonium bromide), an association of a halogenated quaternary nitrogen salt with a halogen molecule (pyridinium bromide bromide), and the like. The inorganic halogen compound may be any compound as long as it is a compound capable of reacting with an organic silver salt to produce a silver halide, and an alkali metal halide or ammonium (sodium chloride, lithium bromide, potassium iodide, ammonium bromide, etc.). ), An alkaline earth metal halide (calcium bromide, magnesium chloride, etc.), a transition metal halide (ferric chloride, cupric bromide, etc.), a metal complex having a halogen ligand (sodium iridate bromide). , Ammonium rhodate, etc.),
There are halogen molecules (bromine, chlorine, iodine). Further, a desired organic / inorganic halide may be used in combination. When the halide is added, the amount of the halide added is 1 mmol as a halogen atom per mol of the organic silver salt.
500 millimole is preferable, and 10 millimole to 250 millimole is more preferable.

The photosensitive silver halide is infrared-sensitized. This is because the photosensitive silver halide is sensitized with a sensitizing dye.
That is, it is spectrally sensitized in the wavelength region of 50 to 1400 nm. The sensitizing dye used may be a known compound, for example, cyanine, merocyanine,
A variety of known dyes, including styryl, hemicyanine, oxonol, hemioxonol and xanthene dyes, can be spectrally advantageously sensitized. Useful cyanine dyes are, for example, cyanine dyes having a basic nucleus such as thiazoline nucleus, oxazoline nucleus, pyrroline nucleus, pyridine nucleus, oxazole nucleus, thiazole nucleus, selenazole nucleus and imidazole nucleus. Preferred useful merocyanine dyes are, in addition to the basic nucleus described above, a thiohydantoin nucleus, a rhodanine nucleus, an oxazolidinedione nucleus, a thiazolinedione nucleus, a barbituric acid nucleus,
It also includes acidic nuclei such as thiazolinone nuclei, malononitrile nuclei and pyrazolone nuclei. Among the above cyanine and merocyanine dyes, those having an imino group or a carboxyl group are particularly effective. For example, US Pat.
1,279, 3,719,495, 3,87
7,943, 5,541,054, British Patent 1,
466, 201, 1,469,117, 1,4
No. 22,057, Japanese Examined Patent Publication No. 3-10391, No. 6-52
387, JP-A-5-341432, 6-1947.
No. 81, No. 6-301141, No. 9-166844.
No. 2000-95958, 2000-171.
938, 2000-227642, 2000-
250166, 2000-258870, 200
It may be appropriately selected from known dyes such as those described in JP-A No. 1-83655 and JP-A No. 11-316437.

The sensitizing dyes for spectrally sensitizing the photosensitive silver halide may be used alone or in combination of two or more kinds. In the present invention, the sensitizing dye is added to the silver halide emulsion preferably after the desalting step and before coating, more preferably after the desalting step and before the start of chemical ripening. The addition amount of the sensitizing dye, can be the desired amount performance combined with the sensitivity and fog, it is preferred per mol of silver halide 10 ^-6 to 1 mol of the photosensitive layer, more preferably 10 ^{- It is 4} to 10 ^-1 mol.

A supersensitizer can be used in the photosensitive silver halide in order to improve the spectral sensitization efficiency. Examples of the supersensitizer include European Patent Publication No. 587,338, U.S. Pat. No. 3,877,943, and No. 4,873,18.
4, JP-A-5-341432 and 11-10954.
The compounds described in No. 7, No. 10-111543 and the like can be mentioned.

Specific examples of infrared sensitizing dyes for infrared sensitizing a photosensitive silver halide are shown below, but the present invention is not limited to these specific examples. However, in the specific example, T,
“P-Ts ⁻ ” indicates paratoluenesulfonate ion.

[0083]

[Chemical 17]

[0084]

[Chemical 18]

[0085]

[Chemical 19]

[0086]

[Chemical 20]

[0087]

[Chemical 21]

Next, the binder will be described. The binder is a natural or synthetic resin, for example, gelatin, polypininorebutyral, polyvinyl acetal, polyvinyl chloride, polyvinyl acetate, cellulose acetate, polyolefin, polyester, polystyrene, polyacrylonitrile, polycarbonate, polyvinyl butyral, butyl ethyl cellulose, methacrylate copolymer, anhydrous. Maleic acid ester copolymer,
Any of polystyrene and butadiene-styrene copolymer can be used. In particular, the photosensitive layer preferably contains polyvinyl butyral as a binder. Specifically, polyvinyl butyral is used as a binder in an amount of 5 relative to the total binder content of the photosensitive layer.
It is to use 0% by weight or more. Of course, copolymers and terpolymers are also included. The preferred total amount of polyvinyl butyral is 50% by weight or more and 100% by weight or less, more preferably 70% by weight or more and 100% by weight or less, based on the total binder composition of the photosensitive layer. The Tg of the binder is preferably in the range of 40 to 90 ° C, more preferably 50 to 80 ° C. Here, Tg is a glass transition humidity.

The total amount of binder is used, for example, in an amount sufficient to hold the components of the photosensitive layer in the layer. That is, it is used within a range effective to function as a binder. The effective range can be appropriately determined by those skilled in the art. As a standard for holding at least the organic silver salt, the ratio of the binder to the organic silver salt is 1 by mass.
A range of 5: 1 to 1: 3, particularly 8: 1 to 1: 2 is preferable.

Next, the support will be described. As the support, a polyester film, an undercoated polyester film, a poly (ethylene terephthalate) film, a polyethylene naphthalate film, a cellulose nitrate film, a cellulose ester film, a poly (vinyl acetal) film, a polycarbonate film and a related or resinous material. , And glass, paper, metal and the like. Also, flexible substrates, especially partially acetylated, or baryta and / or α-olefin polymers, especially polyethylene, polypropylene (C2-C10 α-olefin polymers such as ethylene-butene copolymers. It is also possible to use a paper support coated with the support, which may be transparent or opaque, but is preferably transparent.

Other suitable additives and the layer structure of the photosensitive material will be described below. In the photothermographic material of the present invention, a phenol derivative represented by the formula (A) described in Japanese Patent Application No. 11-73951 is preferably used as a development accelerator.

In the photothermographic material of the present invention, when the reducing agent has an aromatic hydroxyl group (—OH), particularly in the case of bisphenols, a group capable of forming a hydrogen bond with these groups. It is preferable to use a non-reducing compound having In the present invention, since the polyphenol compound represented by the general formula (1) is contained as the reducing agent, it is particularly preferable to use a non-reducing compound together. The group forming a hydrogen bond with a hydroxyl group (or an amino group) includes a phosphoryl group, a sulfoxide group, a sulfonyl group, a carbonyl group, an amide group, an ester group, a urethane group, a ureido group,
Examples thereof include tertiary amino groups and nitrogen-containing aromatic groups. Among them, preferred are a phosphoryl group, a sulfoxide group and an amide group (however,> N-Ra (Ra does not have a> N-H group,
Is a substituent other than H). ),
Urethane group (however,> N-H group is not included,> N-Ra
(Ra is a substituent other than H) is blocked. ), Ureido group (provided that> N-H group is not included, and> N
-Ra (wherein Ra is a substituent other than H) is blocked. ). In the present invention, a particularly preferred hydrogen-bonding compound is a compound represented by the following general formula (4).

[0093]

[Chemical formula 22]

In formula (4), R ⁴¹ to R ⁴³ 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 are unsubstituted. May have a substituent. R ⁴¹
When R ⁴³ has a substituent, the substituent is a halogen atom, an alkyl group, an aryl group, an alkoxy group, an amino group, an acyl group, an acylamino group, an alkylthio group,
Arylthio group, sulfonamide group, acyloxy group,
Examples thereof include an oxycarbonyl group, a carbamoyl group, a sulfamoyl group, a sulfonyl group and a phosphoryl group, and an alkyl group and an aryl group are preferable. Specifically, methyl group, ethyl group, isopropyl group, t-butyl group, t-octyl group, phenyl group, 4-alkoxyphenyl group, 4
-Acyloxyphenyl groups and the like.

In the general formula (4), the alkyl group represented by R ⁴¹ to R ⁴³ is specifically a methyl group, an ethyl group, a butyl group, an octyl group, a dodecyl group, an isopropyl group, a t-butyl group or a t-amyl group. Group, t-octyl group, cyclohexyl group, 1-methylcyclohexyl group, benzyl group, phenethyl group, 2-phenoxypropyl group and the like.

In the general formula (4), the aryl group of R ⁴¹ to R ⁴³ is a phenyl group, a cresyl group, a xylyl group, a naphthyl group, a 4-t-butylphenyl group, a 4-t-octylphenyl group, a 4- Examples thereof include anisidyl group and 3,5-dichlorophenyl group. Phenyl group and 4-t-butylphenyl group are preferable, and 4-t-butylphenyl group is particularly preferable.

In formula (4), the alkoxy group for R ⁴¹ to R ⁴³ is a methoxy group, an ethoxy group, a butoxy group,
Octyloxy group, 2-ethylhexyloxy group, 3,
Examples thereof include a 5,5-trimethylhexyloxy group, a dodecyloxy group, a cyclohexyloxy group, a 4-methylcyclohexyloxy group and a benzyloxy group.

In the general formula (4), the aryloxy group of R ⁴¹ to R ⁴³ is a phenoxy group, a cresyloxy group,
Examples thereof include an isopropylphenoxy group, a 4-t-butylphenoxy group, a naphthoxy group and a biphenyloxy group.

In the general formula (4), the amino group of R ⁴¹ to R ⁴³ is dimethylamino group, diethylamino group, dibutylamino group, dioctylamino group, N-methyl-N-
Hexylamino group, dicyclohexylamino group, diphenylamino group, N-methyl-N-phenylamino group and the like can be mentioned.

In the general formula (4), examples of the heterocyclic group represented by R ⁴¹ to R ⁴³ include a pyridyl group, a pyrimidyl group and a triaridyl group.

In formula (4), R ⁴¹ to R ⁴³ are preferably an alkyl group, an aryl group, an alkoxy group or an aryloxy group. In view of the effect of the present invention, R ⁴¹ to R ⁴³
It is preferable that at least one of them is an alkyl group or an aryl group, and it is more preferable that two or more are an alkyl group or an aryl group. Further, it is preferable that R ⁴¹ to R ⁴³ are the same group in that they can be obtained at low cost.

Specific examples of the hydrogen-bonding compound including the compound represented by the general formula (4) are shown below, but the invention is not limited thereto.

[0103]

[Chemical formula 23]

[0104]

[Chemical formula 24]

Specific examples of the hydrogen-bonding compound include, in addition to the above, Japanese Patent Application Nos. 2000-192191 and 2000-19481.
The items described in No. 1 are listed.

The hydrogen-bonding compound (the compound represented by the general formula (4)) can be contained in the coating liquid in the form of a solution, an emulsion dispersion, or a solid dispersion fine particle dispersion, similar to the reducing agent. It can be used in a light-sensitive material. The hydrogen-bonding compound forms a hydrogen-bonding complex with a compound having a phenolic hydroxyl group or an amino group in a solution state, and is isolated in a crystalline state as a complex depending on the combination of the reducing agent and the hydrogen-bonding compound. be able to. It is particularly preferable to use the crystal powder thus isolated as a solid fine particle dispersion in order to obtain stable performance. In addition, a reducing agent and a hydrogen-bonding compound are mixed in a powder,
A method of forming a complex at the time of dispersion with a sand grinder mill using an appropriate dispersant can also be preferably used.

The hydrogen-bonding compound (compound represented by the general formula (4)) is preferably used in the range of 1 to 200 mol% with respect to the reducing agent, more preferably 10 to 15%.
It is in the range of 0 mol%, and more preferably in the range of 30 to 100 mol%.

In the photothermographic material of the present invention, it is preferable that at least one selected from a heteroaromatic mercapto compound and a heteroaromatic disulfide is contained on the same surface of the support as the photosensitive silver halide-containing surface. It is preferable from the viewpoint that the development can be controlled by suppressing or accelerating the development. Hereinafter, the heteroaromatic mercapto compound and the heteroaromatic disulfide will be described.

Heteroaromatic mercapto compounds are Ar--S
Those represented by M are preferred. In the formula, M is a hydrogen atom or an alkali metal atom, and Ar is an aromatic ring or a condensed aromatic ring having one or more nitrogen, sulfur, oxygen, selenium or tellurium atoms. The heteroaromatic ring is benzimidazole, naphthuimidazole, benzothiazole, naphthothiazole, benzoxazole, naphthoxazole, benzoselenazole, benzotelrazole, imidazole, oxazole, pyrazole, triazole, thiadiazole, tetrazole, triazine,
Pyrimidine, pyridazine, pyrazine, pyridine, purine, quinoline or quinazolinone are preferred, and benzimidazole, benzothiazole, benzoxazole,
Benzotetrazole is more preferred. Further, the heteroaromatic ring is, for example, halogen (for example, Br and Cl),
Hydroxy, amino, carboxy, alkyl (eg,
One or more carbon atoms, preferably having 1 to 4 carbon atoms), alkoxy (for example having 1 or more carbon atoms, preferably 1 to 4 carbon atoms) and aryl (substituents) May be included).

Examples of the heteroaromatic mercapto compound include 2
-Mercaptobenzimidazole, 2-mercaptobenzoxazole, 2-mercaptobenzothiazole, 2
-Mercapto-5-methylbenzimidazole, 6-ethoxy-2-mercaptobenzothiazole, 2,2'-
Dithiobis- (benzothiazole, 3-mercapto-
1,2,4-triazole, 4,5-diphenyl-2-
Imidazole thiol, 2-mercapto imidazole,
1-ethyl-2-mercaptobenzimidazole, 2-
Mercaptoquinoline, 8-mercaptopurine, 2-mercapto-4 (3H) -quinazolinone, 7-trifluoromethyl-4-quinolinethiol, 2,3,5,6-tetrachloro-4-pyridinethiol, 4-amino- 6-hydroxy-2-mercaptopyrimidine monohydrate,
2-amino-5-mercapto-1,3,4-thiadiazole, 3-amino-5-mercapto-1,2,4-triazole, 4-hydroxy-2-mercaptopyrimidine, 2-mercaptopyrimidine, 4,6- Diamino-2
-Mercaptopyrimidine, 2-mercapto-4-methylpyrimidine hydrochloride, 3-mercapto-5-phenyl-1,2,4-triazole, 1-phenyl-5-
Examples include mercaptotetrazole, sodium 3- (5-mercaptotetrazole) -benzenesulfonate, N-methyl-N ′-[3- (5-mercaptotetrazolyl) phenyl] urea, and 2-mercapto-4-phenyloxazole. However, the present invention is not limited to these.

The addition amount of the heteroaromatic mercapto compound is preferably in the range of 0.001 to 1 mol per mol of silver in the emulsion layer, and more preferably in the range of 0.003 to 0.1 mol per mol of silver. . The term "1 mol of silver" as used herein means 1 mol of silver halide.

The heteroaromatic disulfide compound is Ar-
Those represented by S-S-Ar are preferable. Wherein Ar is an aromatic ring or fused aromatic ring having one or more nitrogen, sulfur, oxygen, selenium or tellurium atoms. Examples of the heteroaromatic ring include benzimidazole, naphthoimidazole, benzothiazole, naphthothiazole, benzoxazole, naphsoxazole, benzoselenazole, benzotelrazole, imidazole, oxazole, pyrazole, triazole, thiadiazole, tetrazole, triazine, pyrimidine, pyridazine and pyrazine. , Pyridine, purine, quinoline or quinazolinone are preferred, benzimidazole, benzothiazole,
Benzoxazole and benzotetrazole are more preferable. As the heteroaromatic ring, for example, halogen (for example,
Br and Cl), hydroxy, amino, carboxy,
Alkyl (eg, one or more carbon atoms, preferably 1
~ Having 4 carbon atoms), alkoxy (for example having 1 or more carbon atoms, preferably having 1 to 4 carbon atoms) and aryl (which may have a substituent). It may have one selected from the group of substituents.

The amount of the heteroaromatic disulfide compound added is preferably in the range of 0.001 to 1 mol per mol of silver in the emulsion layer, and 0.003 to 0.1 per mol of silver.
A molar range is more preferred. The term "1 mol of silver" as used herein means 1 mol of silver halide.

The photothermographic material of the present invention preferably contains a toning agent. Regarding the color toning agent, JP-A-10-62
899 paragraphs 0054-0055, European Patent Publication No. 0803764 Al, page 1, lines 23-48,
It is described in Japanese Patent Application No. 10-213487, and in particular,
Phthalazinones, phthalazine, phthalazinone derivatives or metal salts; for example, 4- (1-naphthylphthalazinone, 6-chlorophthalazinone 5,7-dimethoxyphthalazinone and 2,3-dihydro-1,4-phthalazinedione ); A combination of phthalazinones and phthalic acids (eg, phthalic acid, 4-methylphthalic acid, 4-nitrophthalic acid and tetrachlorophthalic anhydride); phthalazines (phthalazine, phthalazine derivatives or metal salts; eg 4
-(1-naphthyl) phthalazine, 6-isopropylphthalazine, 6-t-butylflatazine, 6-chlorophthalazine, 5,7-dimethoxyphthalazine and 2,3-dihydrophthalazine); phthalazines and phthalic acids Is preferred, and a combination of phthalazines and phthalic acids is particularly preferred. The toning agent is preferably contained in an amount of 0.1 to 50% mol, and more preferably 0.5 to 20% mol, per mol of silver on the surface having the image forming layer.

In the photothermographic material of the present invention, the silver halide emulsion and / or the organic silver salt is further protected against the formation of additional fog by the antifoggant, the stabilizer and the stabilizer precursor, It can be stabilized against a decrease in sensitivity during stock storage. Suitable antifoggants, stabilizers and stabilizer precursors that can be used alone or in combination are the thiazoniums described in US Pat. Nos. 2,131,038 and 2,694,716. Salts, azaindenes described in US Pat. Nos. 2,886,487 and 2,444,605, JP-A-9-329865 and US Pat.
Compounds described in US Pat. No. 3,681, US Pat. No. 2,7
No. 28,663, the mercury salt described in US Pat.
Urazole described in US Pat. No. 287,135, sulfocatechol described in US Pat. No. 3,235,652, oxime, nitrone, nitroindazole described in British Patent No. 623,448, US Pat. 2,8
39,405, polyvalent metal salts, US Pat. No. 3,220,839, thiuronium salts,
U.S. Pat. Nos. 2,566,263 and 2,5
97,915, palladium, platinum and gold salts, halogen-substituted organic compounds described in US Pat. Nos. 4,108,665 and 4,442,202, US Pat. , 128,557, 4,137,079, 4,138,365, and 4,459,350, and the triazines described in U.S. Pat. No. 4,411. , 985, and the like.

Organic halides are preferable as the antifoggant, and polyhalomethyl compounds, especially trihalomethylsulfone compounds are particularly preferable. Organic halides are described in, for example, Japanese Patent Publication No. 50-119624 and No. 50-196624.
No. 120328, No. 51-121332, No. 54-58022, No. 56-70543,
56-99335, 59-90842, 61-129642 and 62-12984.
No. 5, JP-A-6-208191, and JP-A 7-56.
21 gazette, the same 7-2781 gazette, the same 8-15809.
No. 9-160167 and No. 9-24417.
7 gazette, 9-244178 gazette, and 9-2583 gazette.
67 publication, 9-265150 publication, 9-319 publication.
No. 022, No. 10-171063, No. 11-
No. 21221, No. 11-231460, No. 11-242304, and US Pat. No. 5,340,7.
No. 12, No. 5,369,000, and No. 5,464,737, and compounds such as 2- (tribromomethyl sulfone ) Quinoline, 2- (tribromomethylsulfone) pyridine, tribromomethylphenyl sulfone, tribromomethylnaphthal sulfone and the like.

In the photothermographic material of the present invention, it may be advantageous to add a mercury (II) salt as an antifoggant to the photosensitive layer. Preferred mercury (II) salts for this purpose are mercury acetate and mercury bromide. The addition amount of mercury used in the present invention is preferably 1 nanomol (nmol) to 1 mmol (mmo) per 1 mol of coated silver.
l), more preferably 10 nanomolar (nmol) to 1
It is in the range of 00 micromol (μmol).

The photothermographic material of the present invention may contain benzoic acids for the purpose of increasing sensitivity and preventing fog. As the benzoic acids, any benzoic acid derivative can be used, but as an example of a preferable structure, US Pat.
84,939, 4,152,160, JP-A-9-281687, and 9-32986.
Examples thereof include compounds described in JP-A No. 4 and JP-A No. 9-329865. The benzoic acid used in the present invention may be added to any part of the light-sensitive material, but as an addition layer, it is preferable to add it to the layer having the photosensitive layer, and further to the organic silver salt-containing layer. preferable. The benzoic acid may be added at any step of the coating solution preparation, and when it is added to the organic silver salt-containing layer, it may be any step from the organic silver salt preparation to the coating solution preparation, but after the organic silver salt preparation. Therefore, immediately before coating is preferable. The benzoic acid may be added by any method such as powder, solution and fine particle dispersion. Also, it may be added as a solution mixed with other additives such as a sensitizing dye, a reducing agent, and a toning agent. The amount of the benzoic acid added may be any amount, but 1 micromol (μmol) or more and 2 mol (mo) per 1 mol of silver.
l) or less is preferable and 1 mmol or more and 0.1.
It is more preferably 5 mol or less.

The photothermographic material of the present invention may contain a plasticizer and a lubricant, and the plasticizer and the lubricant which can be used in the photosensitive layer are described in JP-A No. 11-65021, paragraph No. 0117, ultrahigh contrast. Regarding the ultra-high contrast agent for image formation and the addition method and amount thereof, paragraph No. 011 of the same item
8, JP-A No. 11-223898, paragraph numbers 0136 to 0
193, compounds of formula (H), formulas (1) to (3), formulas (A) and (B) of Japanese Patent Application No. 11-87297, Japanese Patent Application No.
Regarding compounds of the general formulas (III) to (V) (specific compounds: chemical formulas 21 to 24) described in JP-A No. 1-91652 and a contrast enhancing accelerator, paragraph No. 0102 of JP-A No. 11-65021.
JP-A No. 11-223898, paragraph numbers 0194 to 019
5 are described.

In the photothermographic material of the present invention, the photosensitive silver halide grain-containing layer preferably has an absorption at an exposure wavelength of 0.1 or more and 0.6 or less, and 0.2 or more and 0.5 or less.
The following is more preferable. Dm when absorption is large
If the absorption is low, the sharpness may be impaired because the in increases and the image becomes difficult to discriminate. Any method may be used to impart absorption to the photosensitive silver halide layer in the present invention, but it is preferable to use a dye. As the dye, any dye may be used as long as it satisfies the above-mentioned absorption condition,
For example, pyrazoloazole dye, anthraquinone dye, azo dye, azomethine dye, oxonol dye, carbocyanine dye, styryl dye, triphenylmethane dye,
Examples include indoaniline dye, indophenol dye, squarylium dye and the like. Preferred dyes used in the present invention are anthraquinone dyes (see, for example, JP-A No.
Compounds 1 to 9 described in JP-A-341441, JP-A-5-
Compounds 3-6 to 18 and 8-described in Japanese Patent No. 165147
23-38), azomethine dyes (JP-A-5-341)
Compounds 17 to 47 and the like described in JP 441), indoaniline dyes (for example, compounds 11 to 19 described in JP-A-5-289227, compound 47 described in JP-B-5-341441, and JP-A-5-165147). Compounds 2-10 to 11 described in the official gazette), azo dyes (JP-A-5-3
The compounds 10 to 16 described in JP-A-41441 and the squarylium dyes (compounds 1 to 20 described in JP-A-10-104779 and compounds la to 3d described in US Pat. No. 5,380,635). As a method for adding these dyes, any method such as a solution, an emulsion, a dispersion of group fine particles, and a state of being mordanted with a polymer mordant may be used. The amount of these compounds used is determined depending on the intended amount of absorption, but it is generally preferable to use in the range of 1 μg or more and 1 g or less per 1 m ² .

In the photothermographic material of the present invention, it is preferable that any portion other than the photosensitive silver halide grain-containing layer has an absorption at an exposure wavelength of 0.1 to 3.0,
It is more preferably 0.3 or more and 2.0 or less from the viewpoint of halation prevention. As the portion having absorption at the exposure wavelength, a layer of the photosensitive silver halide grain-containing layer on the opposite side of the support (back layer, back surface undercoat or undercoat layer, back layer protective layer) or photosensitive layer Between the layer containing the functional silver halide grains and the support (undercoat or undercoat layer) is preferred. Although the photosensitive silver halide grains are spectrally sensitized in the infrared region in the present invention, any method may be used in order to make the portion other than the layer containing the photosensitive silver halide grains have absorption. The absorption maximum in the region is preferably 0.3 or less. The dye used for coloring may be the same as the dye used for absorbing the light-sensitive silver halide layer, and may be the same as or different from the dye used for the light-sensitive silver halide layer. . When the photosensitive silver halide grains are spectrally sensitized in the visible region, any method may be used to make the portion other than the photosensitive silver halide grain-containing layer absorb, but a dye or a dye which is decolorized by heat treatment or It is preferable to use a combination of a compound which is decolorized by heat treatment and a dye which is decolorized. Examples of the colored layer that is erased include the following, but the present invention is not limited thereto. JP-A-52-139
No. 136, No. 53-132334, No. 56-
No. 501480, No. 57-16060, No. 5
7-68831, 57-101835,
No. 59-182436, JP-A No. 7-36145, No. 7-199409, and Japanese Patent Publication No. 48-386.
No. 92, No. 50-16648, Japanese Patent Publication No. 2-4
1734, U.S. Pat. Nos. 4,088,497, 4,283,487, and 4,54.
Nos. 8,896 and 5,187,049 are disclosed. The amount of these compounds used is determined by the amount of absorption desired, but is generally 1 μm / m ² .
It is preferably used in the range of g or more and 1 g or less.

In the photothermographic material of the present invention, various dyes and pigments (for example, CI Pigment Blue 60, C, etc.) are used for the photosensitive layer from the viewpoints of color tone improvement, prevention of interference fringes during laser exposure, and prevention of irradiation. .IP
igment Blue 64, C.I. I. Pigmen
t Blue 15: 6) can be used. Regarding these, WO98 / 36322, JP-A-10-2
68465, 11-338098 and the like.

The photothermographic material of the invention has a non-photosensitive layer (non-image forming layer) in addition to the photosensitive layer (image forming layer). The non-photosensitive layer is (1) a protective layer provided on the photosensitive layer (the side farther than the support) from the arrangement, (2)
An intermediate layer provided between a plurality of photosensitive layers or between a photosensitive layer and a protective layer, (3) an undercoat layer provided between the photosensitive layer and a support, and (4) on the opposite side of the photosensitive layer. It can be classified into a back layer provided. The filter layer is (1) or (2)
Is provided as a layer on the photosensitive material. The antihalation layer is provided on the photosensitive material as the layer (3) or (4). It is preferable to provide the antihalation layer on the side far from the light source with respect to the photosensitive layer.

The antihalation layer is described in JP-A-1.
No. 1-65021, paragraph numbers 0123 to 0124, JP-A Nos. 11-223898, 9-230531, and 10
-36695, 10-104779, 11-2.
31457, 11-352625, 11-35.
No. 2626 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 using a dye having absorption in the visible region to prevent halation, it is preferable that the color of the dye does not substantially remain after image formation, and a means for erasing by heat of heat development is used. It is particularly preferable to add a heat-decolorizable dye and a base precursor to the non-photosensitive layer so that the non-photosensitive layer functions as an antihalation layer. Regarding these techniques, JP-A-11-2
No. 31457 and the like.

The addition amount of the decolorizing dye is determined depending on the use of the dye. Generally, it is used in such an amount that the optical density (absorbance) measured at a target wavelength exceeds 0.1. The optical density is preferably 0.2 to 2. The amount of dye used to obtain such an optical density is generally 0.00
It is about 1 to 1 g / m ² .

By decoloring the dye in this way, the optical density after thermal development can be lowered to 0.1 or less. Two or more kinds of decolorizable dyes may be used together in the thermally decolorizable recording material or the photothermographic material. Similarly, two or more kinds of base precursors may be used in combination. In thermal erasing using such an erasing dye and a base precursor,
It is preferable to use in combination with a substance (for example, diphenyl sulfone, 4-chlorophenyl (phenyl) sulfone) that lowers the melting point by 3 ° C. (deg) or more when mixed with a base precursor as described in JP-A-11-352626. Etc. are preferable.

In the photothermographic material of the invention, a colorant having an absorption maximum at 300 to 450 nm can be added for the purpose of improving the silver tone and the change of the image with time. Such colorants are disclosed in JP-A-62-210458 and 63-
104046, 63-103235, 63-2
08846, 63-306436, 63-31
No. 4535, JP-A No. 01-61745, Japanese Patent Application No. 11-
No. 276751. Such a colorant is usually added in the range of 0.1 mg / m ^{2 to 1} g / m ² , and the layer to be added is preferably a back layer provided on the opposite side of the photosensitive layer.

In the photothermographic material of the present invention, a surface protective layer can be provided for the purpose of preventing adhesion of the photosensitive layer (image forming layer). Any polymer may be used as the binder of the surface protective layer. Examples of this binder include polyester, gelatin, polyvinyl alcohol, and cellulose derivatives, with cellulose derivatives being preferred. Examples of the cellulose derivative are shown below, but the invention is not limited thereto. Examples of the cellulose derivative include cellulose acetate, cellulose acetate butyrate, cellulose propionate, hydroxypropyl cellulose, hydroxypropylmethyl cellulose, methyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, and mixtures thereof. The thickness of the surface protective layer is 0.1 to 10 μm
Is preferable, and 1-5 micrometers is especially preferable.

Any anti-adhesion material may be used for the surface protective layer. Examples of anti-adhesion materials are waxes, liquid paraffin, silica particles, styrene-containing elastomeric block copolymers (eg styrene-butadiene-styrene, styrene-isoprene-styrene), cellulose acetate, cellulose acetate butyrate, cellulose propionate. And mixtures of these.

In the photothermographic material of the present invention, the photosensitive layer or the protective layer (surface protective layer) of the photosensitive layer is described in US Pat. Nos. 3,253,921 and 2,274.
Light absorbing materials and filter dyes such as those described in US Pat. Nos. 782, 2,527,583 and 2,956,879 may be included.
Further, a dye can be mordanted as described in, for example, US Pat. No. 3,282,699. The amount of the filter dye used is 0.1 as the absorbance at the exposure wavelength.
-3 are preferable and 0.2-1.5 are especially preferable.

In the photothermographic material of the present invention, the photosensitive layer or the protective layer (surface protective layer) of the photosensitive layer includes a matting agent such as starch, titanium dioxide, zinc oxide, silica, US Pat. Polymeric beads, including beads of the type described in 992,101 and 2,701,245 may be included. Also, the matteness of the emulsion surface may be anything as long as stardust failure does not occur, but the Beck smoothness is 200 seconds or more 100
00 seconds or less is preferable, and 300 seconds or more and 10,000 seconds or less is particularly preferable.

In the photothermographic material of the present invention, the photosensitive layer is composed of one or more layers on the support.
The one-layer constitution may contain organic silver salt, silver halide, reducing agent and binder, and optional additional materials such as other auxiliary agents mentioned above. The two-layer structure is the first
Organic silver salts and silver halide are included in the photosensitive layer (usually the layer adjacent to the substrate) and some other components can be included in the second layer or both layers. A two layer construction comprising a single photosensitive layer containing all components and a protective topcoat (surface protective layer) is also contemplated. The construction of a multicolor light-sensitive photothermographic material may include combinations of these two layers for each color, and all in a single layer as described in US Pat. No. 4,708,928. May be included. In the case of multi-dye multicolor light-sensitive photothermographic materials, each light-sensitive layer generally contains a functional or functional layer between each light-sensitive layer as described in U.S. Pat. No. 4,460,681. The use of non-functional barrier layers keeps them distinct from each other.

The photothermographic material of the present 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.

A matting agent may be added to the photothermographic material of the present invention in order to improve transportability. Matting agents are generally fine particles of water-insoluble organic or inorganic compounds.
Any matting agent can be used, for example, US Pat. Nos. 1,939,213 and 2,701,24.
5, No. 2,322,037, No. 3,2
62,782, 3,539,344, 3,767,448 and the like, organic matting agents described in the respective specifications, 1,260,772 and 2 No. 192,241, No. 3,257,206, No. 3,370,951 and No. 3,52.
Those well known in the art such as the inorganic matting agents described in the respective specifications such as the specifications of Nos. 3,022 and 3,769,020 can be used. For example, specifically as an example of an organic compound that can be used as a matting agent, as an example of a water-dispersible vinyl polymer, polymethyl acrylate, polymethyl methacrylate, polyacrylonitrile, acrylonitrile-α-methylstyrene copolymer, polystyrene , Styrene-divinylbenzene copolymer, polyvinyl acetate, polyethylene carbonate, polytetrafluoroethylene, etc. Examples of cellulose derivatives are methyl cellulose, cellulose acetate, cellulose acetate propionate, etc. Examples of starch derivatives are carboxy starch, carboxynitrophenyl Starch, urea-formaldehyde-starch reaction product, etc.
Gelatin which has been hardened with a known hardening agent and hard gelatin which has been made into microcapsule hollow particles by hardening coacervate can be preferably used. Preferred examples of the inorganic compound include silicon dioxide, titanium dioxide, magnesium dioxide, aluminum oxide, barium sulfate, calcium carbonate, silver chloride desensitized by a known method, and silver bromide (glass, diatomaceous earth, etc.). The above-mentioned matting agent can be used by mixing different kinds of substances as necessary.The size and shape of the matting agent are not particularly limited, and those having an arbitrary particle size can be used. In practice, it is preferable to use particles having a particle diameter of 0.1 μm to 30 μm, and the particle size distribution of the matting agent may be narrow or wide. Since it has a great influence, it is preferable to make the particle size, shape and particle size distribution as necessary during the preparation of the matting agent or by mixing a plurality of matting agents.

Examples of the layer that can contain a matting agent include the outermost layer (which may be a photosensitive layer or a back layer) on the photosensitive layer surface and the back surface, a protective layer, an undercoat layer, and the like.
It is preferably contained in the outermost surface layer, a layer functioning as the outermost surface layer, or a layer close to the outer surface, and preferably contained in a layer acting as a so-called protective layer. The matteness of the back side is Beck's smoothness of 250
Seconds or less, 10 seconds or more is preferable, and 180 is more preferable.
Seconds or less and 50 seconds or more.

Suitable binders for the backing layer are transparent or translucent, generally colorless, and include natural polymeric synthetic resins, polymers and copolymers, and other film-forming media such as gelatin, gum arabic, poly (vinyl alcohol), Hydroxyethyl cellulose, cellulose acetate, cellulose acetate butyrate, poly (vinylpyrrolidone), casein, starch, poly (acrylic acid), poly (methylmethacrylic acid), poly (vinyl chloride), poly (methacrylic acid), copoly (styrene-
Maleic anhydride), copoly (styrene-acrylonitrile), copoly (styrene-butadiene), poly (vinyl acetal) s (for example, poly (vinyl formal) and poly (vinyl butyral)), poly (ester) s,
There are poly (urethane) s, phenoxy resins, poly (vinylidene chloride), poly (epoxides), poly (carbonates), poly (vinyl acetate), cellulose esters, poly (amides). The binder may be formed by coating with water, an organic solvent or an emulsion.

The photothermographic material of the present invention is described in US Pat. Nos. 4,460,681 and 4,374,92.
No. 1 backside resistive heating layer (bac)
kside resistive heating l
ayer) can also be used.

In the photothermographic material of the present invention, a hardener may be used for each layer such as the photosensitive layer, the protective layer and the back layer. Examples of hardeners include US Pat. No. 4,281,0
No. 60, JP-A-6-208193, and other polyisocyanates described in US Pat.
For example, epoxy compounds described in Japanese Patent No. 91,042, vinyl sulfone compounds described in Japanese Patent Application Laid-Open No. 62-89048 and the like are used.

In the photothermographic material of the present invention, a surfactant may be used for the purpose of improving coatability and charging. As an example of the surfactant, any of nonionic, anionic, cationic, and fluorine-based can be appropriately used.
Specifically, fluorine-containing polymer surfactants described in JP-A-62-170950, US Pat. No. 5,380,644, JP-A-60-244945, and the like.
Fluorine-based surfactants described in JP-A-63-188135 and the like, polysiloxy acid-based surfactants described in US Pat. No. 3,885,965, and JP-A-6-30.
Examples thereof include polyalkylene oxides and anionic surfactants described in JP-A-1140.

Examples of the solvent include New Solvent Pocket Book (Ohm Co., 1994), but the present invention is not limited thereto. The boiling point of the solvent used in the present invention is preferably 40 ° C or higher and 180 ° C or lower. Specifically as an example of the solvent, hexane,
Cyclohexane, toluene, methanol, ethanol,
Isopropanol, acetone, methyl ethyl ketone, ethyl acetate, 1,1,1-trichloroethane, tetrahydrofuran, triethylamine, thiophene, trifluoroethanol, perfluoropentane, xylene, n-
Butanol, phenol, methyl isobutyl ketone, cyclohexanone, butyl acetate, diethyl carbonate, chlorobenzene, dibutyl ether, anisole, ethylene glycol diethyl ether, N, N-dimethylformamide, morpholine, propane sultone, perfluorotributylamine, water and the like. .

The photothermographic material of the present invention comprises an antistatic or conductive layer such as a soluble salt (eg chloride, nitrate, etc.), a vapor-deposited metal layer, US Pat. No. 2,861,056 and the same. Ionic polymers as described in US Pat. No. 3,206,312 or US Pat. No. 3,428,4.
It may have a layer containing an insoluble inorganic salt or the like as described in Japanese Patent No. 51.

A method for obtaining a color image using the photothermographic material of the present invention is described in JP-A No. 7-13295, No. 1
There is a method described on page 48, left column, line 48 to 11 left column, line 40. Further, examples of stabilizers for color dye images include British Patent No. 1,326,889 and US Pat. No. 3,43.
No. 2,300, No. 3,698,909, No. 3,574,627, No. 3,57.
Those exemplified in 3,050, 3,764,337 and 4,042,394 can be used.

In the heat-developable light-sensitive material of the present invention, the heat-developable photographic emulsion may be dip coated, air knife coated, flow coated or US Pat. No. 2,38.
It can be coated by various coating operations including extrusion coating using hoppers of the type described in 1,294. If desired, US Pat.
Two or more layers can be coated simultaneously by the methods described in 1,791 and GB 837,095.

An additional layer in the photothermographic material of the invention,
For example, it may include a dye receiving layer for receiving a transfer dye image, an opacifying layer when reflective printing is desired, a protective topcoat layer and primer layers known in the photothermographic art. It is preferable that the photothermographic material of the present invention can form an image with only one light-sensitive material, and it is preferable that a functional layer necessary for image formation such as an image receiving layer does not become another light-sensitive material.

The photothermographic material of the present invention may be developed by any method, but it is usually developed by raising the temperature of the imagewise exposed photosensitive material. The preferred developing temperature is 80 to 250 ° C., more preferably 100 to 250 ° C.
It is 140 ° C. The developing time is preferably 1 to 180 seconds, more preferably 10 to 90 seconds. Also as a developing method, it is preferable to perform development using a heat drum.
The light-sensitive material of the present invention may be exposed by any method, but a laser beam is preferable as an exposure light source. The laser light according to the present invention includes a gas laser, a dye laser,
A semiconductor laser or the like is preferable. Further, a semiconductor laser, a YAG laser, a second harmonic generating element or the like can be used. In the present invention, 750 to 1400 nm
It is preferable to use a laser beam having an exposure wavelength.

[0146]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto.
[Example 1]

<Preparation of PET support> Using terephthalic acid and ethylene glycol, an intrinsic viscosity IV =
0.66 (phenol / tetrachloroethane = 6/4
(Measured at 25 ° C. in (weight ratio)) PET was obtained. This was pelletized, dried at 130 ° C. for 4 hours, melted at 300 ° C., extruded from a T-die and rapidly cooled to prepare an unstretched film having a thickness of 175 μm after heat setting. This was longitudinally stretched 3.3 times using rolls having different peripheral speeds, and then horizontally stretched 4.5 times with a tenter. The temperatures at this time were 110 ° C. and 130 ° C., respectively.
After that, after heat setting at 240 ° C. for 20 seconds, 4% relaxation was carried out in the lateral direction at the same temperature. After slitting the chuck part of the tenter, both ends are knurled and 4 kg
/ Cm ² (4 × 10 ⁴ Pa) and wound up, thickness 175 μm
Got a roll of. Both sides of the support were treated at room temperature at 20 m / min using a solid state corona processor 6KVA model manufactured by Pillar Co. From the readings of current and voltage at this time, 0.375 kV · A · min / m ² was applied to the support.
It was found that the process of. The processing frequency at this time was 9.6 kHz, and the gap clearance between the electrode and the dielectric roll was 1.6 mm.

<Preparation of photosensitive silver halide emulsion> Water 54
Phenylcarbamoyl gelatin 88.3 is added to 29 ml.
g, PAO compound _{(HO (CH 2 CH 2 O} ) n- (CH
_{(CH 3) CH 2 O)} 17 - (CH 2 CH 2 O) m-H; m +
n = 5-7) 10% aqueous methanol solution (10 ml) and potassium bromide (0.32 g) were added and dissolved, and the mixture was kept at 45 ° C.
659 ml of a 0.67 mol / l silver nitrate aqueous solution and 0.703 mol of KBr and 0.013 per liter
A solution containing mol of KI dissolved in JP-B-58-58288
No. 58-58289, the mixing stirrer was used to control the pAg of 8.09 while controlling the simultaneous mixing method.
It took 45 minutes to add and perform nucleation. After 1 minute, 0.
20 ml of 63N potassium hydroxide solution was added. After 6 minutes, 0.67 mol / l silver nitrate aqueous solution 1976 m
1 and 0.657 mol KBr per liter, 0.
A solution in which 013 mol of potassium iodide and 30 μmol of dipotassium hexachloroiridate were dissolved was added at a temperature of 45.
The temperature was controlled at 0 ° C. and pAg 8.09, and the mixture was added by the simultaneous mixing method over 14 minutes and 15 seconds. After stirring for 5 minutes, 40
The temperature was lowered to ℃. To this, 18 ml of a 56% aqueous solution of acetic acid was added to precipitate a silver halide emulsion. The supernatant was removed, leaving 2 liters of the sedimented portion, 10 liters of water was added, and after stirring, the silver halide emulsion was precipitated again. Further, the supernatant was removed, leaving 1.5 liters of the sedimented portion, 10 liters were added, and after stirring, the silver halide emulsion was allowed to settle. After removing the supernatant liquid, leaving 1.5 l of the sedimented portion, a solution of 1.72 g of anhydrous sodium carbonate dissolved in 151 ml of water was added, and the temperature was raised to 60 ° C. It was stirred for another 120 minutes. Finally, the pH was adjusted to 5.0, and water was added so that the amount was 1161 g per mol of silver. This emulsion has an average grain size of 0.058μ.
m, variation coefficient of particle size 12%, [100] plane ratio 9
It was 2% of monodisperse cubic silver iodobromide grains.

<Preparation of powdered organic silver salts A to C> 4720 m
0.7552 mol of behenic acid, arachidic acid, and stearic acid were added in a ratio according to Table 1 to 1 l of pure water and dissolved at 80 ° C., and then 1.5N sodium hydroxide aqueous solution 540. After adding 2 ml and adding 6.9 ml of concentrated nitric acid, it cooled at 55 degreeC and obtained the organic acid sodium solution. While maintaining the temperature of the above-mentioned sodium salt of organic acid at 55 ° C., 45.3 g of the above silver halide emulsion and 450 of pure water.
13 ml was added using a homogenizer (ULTRA-TURRAXT-25) manufactured by IKA JAPAN.
The mixture was stirred at 0 rpm (21.1 KHz as mechanical vibration frequency) for 5 minutes. Next, 1 mol / l silver nitrate solution 70
2.6 ml was added over 2 minutes and stirred for 10 minutes to obtain an organic silver salt dispersion. After that, the obtained organic silver salt dispersion was transferred to a water washing container, deionized water was added thereto, and the mixture was stirred and then allowed to stand to separate the organic silver salt dispersion by flotation to remove the water-soluble salts below. Then, after washing with deionized water and drainage were repeated until the conductivity of the drainage reached 2 μS / cm and centrifugal dehydration was carried out, the weight loss at 40 ° C. disappeared.
Dry with a circulation dryer with warm air with oxygen partial pressure according to
Powdered organic silver salts A to C were obtained.

[0150]

[Table 1]

<Preparation of Photosensitive Emulsion Dispersion> Polyvinyl butyral powder (Butvar B-, manufactured by Monsant Co.)
79) 14.57 g of methyl ethyl ketone (MEK) 1
It was dissolved in 457 g, and 500 g of the powdered organic silver salt was gradually added while stirring with a dissolver DISPERMAT CA-40M type manufactured by VMA-GETZMANN, and sufficiently mixed to form a slurry. A photosensitive emulsion dispersion was prepared by dispersing the above slurry for 2 passes with a GM-2 pressure homogenizer manufactured by SMT. At this time, 1
The processing pressure during the pass was 280 kg / cm ² , and the processing pressure during the two passes was 560 kg / cm ² .

<Preparation of Photosensitive Layer Coating Liquids 1 to 24> MEK was added to a photosensitive emulsion dispersion (50 g) containing an organic silver salt according to Table 2.
Add 15.1 g and add 1 with a dissolver type homogenizer.
Keeping the temperature at 21 ℃ while stirring at 000 rpm,
-390 μl of a 10 wt% methanol solution of an association of 2 molecules of dimethylacetamide / 1 molecule of bromic acid / 1 molecule of bromine was added, and the mixture was stirred for 1 hour. Further, 494 μl of a 10 wt% methanol solution of calcium bromide was added and stirred for 20 minutes. Subsequently, 167 mg of a methanol solution containing 15.9% by weight of dibenzo-18-crown-6 and 4.9% by weight of potassium acetate was added, and the mixture was stirred for 10 minutes.
12 wt% infrared sensitizing dye A and 0.12 wt% infrared sensitizing dye B, 18.3 wt% 2-chlorobenzoic acid, 3
2.6 g of MEK solution of 4.2 wt% salicylic acid-p-toluenesulfonate and 4.5 wt% of 5-methyl-2-mercaptobenzimidazole were added and stirred for 1 hour. After that, the temperature is lowered to 13 ° C and further 30
Stir for minutes. While keeping the temperature at 13 ° C, polyvinyl butyral (Butvar B-79, Monsant)
After adding 13.31 g and stirring for 30 minutes, 1.08 g of a 9.4 wt% tetrachlorophthalic acid solution was added and stirred for 15 minutes. While continuing stirring, the compound of the general formula (1), the general formula (2) or the general formula (3) according to Table 2
And the heteroaromatic mercapto compound were added.
1.1 wt% 4-methylphthalic acid and ME of Dye 1
12.4 g of K solution was added, and 10% by weight of Desmod
ur N3300 (Morvey's Aliphatic Isocyanate)
1.5 g were continuously added, and further 4.27 g of MEK solution of 7.4% by weight of tribromomethyl-2-azaphenylsulfone and 7.2% by weight of phthalazine was added to the photosensitive layer coating solutions 1 to 3. I got 24.

[0153]

[Table 2]

<Preparation of coating liquid for surface protective layer> MEK865
g of cellulose acetate butyrate (Eastman Chemical Co., CAB171)
-15) 96 g, polymethylmethacrylic acid (Rohm & Haas Company, Paraloid A-21) 4.5 g, 1,3-di (vinylsulfonyl) -2-propanol 1.5 g,
1.0 g of benzotriazole and 1.0 g of a fluorine-based activator (Asahi Glass Co., Ltd., Surflon KH40) were added and dissolved, and then 13.6% by weight of cellulose acetate butyrate (Eastman Chemical Co., CAB171).
-15) and 9% by weight of calcium carbonate (Special)
itty Minerals, Super-Pflex
(200) was dispersed in MEK with a dissolver type homogenizer at 8000 rpm for 30 minutes, and 30 g was added and stirred to prepare a surface protective layer coating solution.

<Preparation and Application of Back Surface Side Protective Layer Coating Liquid> While stirring 830 g of MEK, cellulose acetate butyrate (Eastman Chemical) was prepared.
Company, CAB381-20) 84.2 g and polyester resin (Bostic, VitelPE2200B).
4.5 g was added and dissolved. Dye B is added to this dissolved liquid.
Of 0.30 g, and a fluorine-based activator dissolved in 43.2 g of methanol (Surflon KH4, Asahi Glass Co., Ltd.
0) 4.5 g and 2.3 g of a fluorine-based activator (Megafuck F120K, Dainippon Ink and Chemicals, Inc.) were added and sufficiently stirred until they were dissolved. Finally, silica dispersed in a methyl ethyl ketone at a concentration of 1% by a dissolver type homogenizer (WR Grace, Syroid 64X).
6000) 75 g was added and stirred to prepare a coating solution for the back surface. The back surface protective layer coating solution thus prepared was applied and dried on a support by an extrusion coater so that the dry film thickness was 3.5 μm. Drying temperature 100
Drying was carried out for 5 minutes using a drying air having an open-air temperature of 10 ° C.

<Preparation of Photosensitive Material> According to Table 3, the coating solution for photosensitive layers 1 to 24 and the coating solution for surface protective layer were extruded by a coater and a support coated with a back surface protective layer (a surface opposite to the back surface protective layer). Photosensitive materials 1 to 24 were prepared by simultaneously applying multiple layers to the above. For the coating, the photosensitive layer has a silver coating amount of 1.
9 g / m ² , and the surface protective layer was formed so that the dry film thickness was 2.5 μm. Then, it was dried for 10 minutes using a drying air having a drying temperature of 75 ° C. and a dew point temperature of 10 ° C.

The solvent content was defined as the sum of MEK and methanol content of the light-sensitive material thus obtained under the following conditions. Cut out a film area of 46.3 cm ² and cut it into 5
Finely chopped to about mm, store in a dedicated vial, seal with a septum and an aluminum cap, and then use Hewlett-Packard Gas Chromatography (GC) 5971.
The headspace sampler HP7694 type was set. The GC detector is a hydrogen flame ionization detector (F
ID) and the column used DB-624 by J & W.
As the main measurement conditions, the head space sampler heating conditions are 120 ° C. and 20 minutes, and the GC introduction temperature is 150.
The temperature was raised from 45 ° C for 3 minutes to 100 ° C at 8 ° C / minute. The calibration curve was prepared by using a peak area of a chromatogram obtained by storing a fixed amount of the butanol diluted solution of each solvent in a dedicated vial and measuring the same as above. The solvent content of the light-sensitive material was 40 mg / m ² .

A photosensitive material (100 cm ²⁾ was cut out and the photosensitive layer was peeled off in MEK. Pro-Lab Micro Digest A300 type microwave wet decomposition equipment decomposed with sulfuric acid and nitric acid, VG Elemental PQ-Ω type ICP-
Analysis by a calibration curve method using MS (inductively coupled plasma mass spectrometer) revealed that the Zr content in the photosensitive material was A
It was 10 μg or less per 1 mg of g. The compounds used in the examples are shown below.

[0159]

[Chemical 25]

(Evaluation) The obtained photosensitive materials were evaluated as follows. The results are shown in Table 3. (Exposure and development process) Wavelength 800nm-
An exposure machine using a semiconductor laser having a vertical multimode of 820 nm as an exposure source was prototyped, and an exposure by laser scanning was applied from the emulsion side of the light-sensitive material produced as described above. At this time, an image was recorded with the incident angle of the scanning laser light on the exposed surface of the photosensitive material being 75 degrees. After that, using an automatic developing machine having a heat drum, the protective layer of the photosensitive material and the drum surface are brought into contact with each other,
Thermal development was carried out at 124 ° C. for 15 seconds, and the obtained image was evaluated with a densitometer. At that time, the exposed and developed room was 23 ° C,
It was 50% RH. Compared to the case where an image is recorded using a normal scanning laser beam with the incident angle of the scanning laser beam on the exposed surface of the photosensitive material being 90 degrees, the image quality is less likely to be deteriorated due to uneven interference, and unexpectedly. An image with good sharpness and contrast was obtained.

(Evaluation of Photographic Performance) Fog: Laser exposure and thermal development were carried out by the above method, and the fog density in the non-image area was measured by a Macbeth densitometer. -Relative Sensitivity-Relative values are shown by setting the reciprocal of the exposure amount that gives a blackening density of fog plus 1.0 in the light-sensitive material 5 by performing laser exposure and heat development by the above method as 100. -Image color tone-The color tone of an image formed by laser exposure and thermal development according to the above method was evaluated by sensory evaluation. The most preferable color tone is pure black tone, and this is set as 0 point. The case where the magenta taste was the strongest was set to -3 points, and -1, -2, and -3 points were set as the magenta taste became stronger from the pure black tone. Conversely,
When the yellowish color is strongest, it is set to +3 points, and as the yellowish color becomes stronger from pure black tone, it is set to +1, +2, and +3 points.
Practically, it is preferable to be in the range of -1, 0, +1 point. -Image storability-After laser exposure and thermal development by the above method, light is sufficiently applied, the humidity is adjusted at 70% RH for 3 hours, the bag is sealed in a light-shielding bag, and left in an environment of 60 ° C for 72 hours. did. At this time, the change ratio of the minimum density (Dmin) is shown.

[0162]

[Table 3]

From the results of Table 3, in the Examples, the relative sensitivity is in the range of 100 to 110, which is considered to be desirable from a practical viewpoint, even if infrared sensitization is carried out, and the practical viewpoint is also obtained in image color tone evaluation. It can be seen from the above that it is in the preferable range of -1, 0, +1. Further, it can be seen that also in the image storability, the change rate of Dmin is small and a good result is shown. On the other hand, Comparative Examples also show that the evaluation is out of the range that is preferable from the practical point of view in evaluation of photographic performance, evaluation of image color tone, or evaluation of image storability.

[0164]

As described above, according to the present invention, a photothermographic material capable of obtaining an image having a good image storability and a good color tone (close to a pure black tone) even if it is subjected to infrared sensitization, and these An image forming method used can be provided.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Eiichi Okuzu             Fuji Photo, 210 Nakanuma, Minamiashigara City, Kanagawa Prefecture             Within Film Co., Ltd. F-term (reference) 2H123 AB00 AB01 AB03 AB23 AB25                       BA00 BA14 BB00 BB13 BB33                       BB39 CA22 CB00 CB03

Claims (11)

[Claims] 1. A photothermographic material comprising, on one surface of a support, at least a photosensitive silver halide, a non-photosensitive organic silver salt, a reducing agent for silver ions, and a binder. Behenate content of organic silver salt is 53 mol%
It is 80 mol% or more and at least one polyphenol compound represented by the following general formula (1) is contained as the reducing agent, and the photosensitive silver halide is infrared-sensitized. Characterized photothermographic material. [Chemical 1] (In General Formula (1), R ¹¹ and R ^{11 ′} each independently represent a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms. R ¹² and R ^{12 ′} are each independently a hydrogen atom. or .L representing a group substitutable on the benzene ring, -S- group or -CHR ¹³ - .R ¹³ representing the group, .X ¹ and X ¹ represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms ^' Represents each independently a hydrogen atom or a group capable of substituting on the benzene ring.) 2. In the compound represented by the general formula (1), R ¹¹ and R ^{11 ′} each independently have 2 to 3 carbon atoms.
Is a tertiary or tertiary alkyl group, and R ¹² and R ^{12 ′} are
Each independently an alkyl group, L is -CHR ¹³ - a group (. Wherein R ¹³ is hydrogen atom or an alkyl group having 1 to 12 carbon atoms), X ¹ and X ^{1 'is} a hydrogen atom The photothermographic material according to claim 1, wherein 3. In the compound represented by the general formula (1), R ¹¹ , R ^{11 ′} , R ¹² and R ^{12 ′} are methyl groups,
L is -CHR ¹³ - group (. Wherein R ¹³ is a secondary alkyl group having 3 to 12 carbon atoms), and claim 1 in which X ¹ and X ^{1 'is} characterized in that it is a hydrogen atom The photothermographic material described in 1. 4. At least one hindered phenol compound represented by the following general formula (2) is contained on the same surface of the support containing the photosensitive silver halide,
Further, the addition ratio of the compound represented by the following general formula (2) and the compound represented by the above general formula (1) (compound represented by the general formula (2) (mol) / general formula (1) 4. The photothermographic material according to claim 1, wherein the compound (mole) represented is 0.001 to 0.2. [Chemical 2] (In the general formula (2), R ²¹ and R ²² each independently represent a hydrogen atom, an alkyl group or an acylamino group. Provided that each of R ²¹ and R ²² is a 2-hydroxyphenylmethyl group. R ²³ represents a hydrogen atom or an alkyl group, and R ²⁴ represents a substituent capable of substituting on the benzene ring.) 5. The photothermographic material according to claim 1, wherein the content of silver behenate in the non-photosensitive organic silver salt is 55 mol% or more and 75 mol% or less. . 6. The non-photosensitive organic silver salt has an oxygen partial pressure of 15
The photothermographic material according to claim 1, wherein the photothermographic material is dried in an atmosphere of vol% or less. 7. The photosensitive layer contains the photosensitive silver halide, the non-photosensitive organic silver salt, a reducing agent for the silver ions, and the binder. The photothermographic material according to any one of 1. 8. The photothermographic material according to claim 7, wherein the binder contains polyvinyl butyral in an amount of 50% by weight or more and 100% by weight or less based on the total binder content of the photosensitive layer. 9. The support containing at least one selected from a heteroaromatic mercapto compound and a heteroaromatic disulfide compound on the same surface of the support containing the photosensitive silver halide. 9. The photothermographic material according to any one of to 8. 10. An image forming method, which comprises exposing the photothermographic material according to claim 1 to a laser beam having an exposure wavelength of 750 nm to 1400 nm to perform thermal development. 11. The image forming method according to claim 10, wherein heat development is performed using a heat drum.