JPS62229241A - Heat developable photosensitive material having high sensitivity and excellent thermal fogging and reciprocity law failure characteristic - Google Patents

Abstract

PURPOSE:To improve sensitivity by incorporating a specific ratio of iodine into the outermost layer of core/shell type photosensitive silver halide particles and forming a high iodine content phase having the higher iodine content than the iodine content of the outermost layer between the core and the outermost layer. CONSTITUTION:The core/shell type photosensitive silver halide particles formed by coating the inside core with the outside shell are used as a heat developable photosensitive material. The shell is substantially formed of silver bromide or silver iodobromide. The iodine content of the outermost layer of the shell is specified to <=10mol% and the high iodine content phase specified to the iodine content higher by >=6mol% than the iodine content of the outermost layer, more preferably to about 6-40mol% is formed between the outermost layer and the core. The core is substantially formed of silver iodide or silver iodobromide. The iodine content over the entire part of the particles is specified to about 4-40mol. Since the iodine content in the shell is specified, the sensitivity is improved and the thermal fogging specific to heat development is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a heat-developable photosensitive material, and more particularly to a heat-developable photosensitive material that is highly sensitive, has a small thermal capri, and has excellent high-illuminance reciprocity law failure characteristics.

[Background of the Invention Fl] A method in which the development step for obtaining an image is performed by dry heat treatment has many advantages over the conventional wet method in terms of simplicity, processing time, cost, and concerns about pollution. .

Regarding heat-developable photosensitive materials in which the above-mentioned development process can be carried out by dry heat treatment, for example, Japanese Patent Publication No. 43-4921 and No.
This is described in Japanese Patent No. 3-4924, which discloses a black and white type photothermographic material comprising an organic silver salt, silver halide and a reducing agent.

Attempts have also been made to improve such heat-developable photosensitive materials and obtain color images by various methods.

For example, JP-A-57-179840, JP-A No. 57-186
No. 744, No. 57-198458, No. 57-20
No. 7250, No. 58-40551, No. 58-5854
3, No. 58-79247, No. 59-12431, No. 59-22049, No. 59-68730, No. 59-12431, No. 59-22049, No. 59-68730, No.
No. 59-124339, No. 59-124333, No. 5
No. 9-124331, No. 59-159159, No. 59
-181345, 59-159161, 58-
No. 116537, No. 58-123533, No. 58-1
There are No. 49046 and No. 58-149047.

The basic composition of a color type heat-developable photosensitive material for obtaining this color image consists of a photosensitive element and an image receiving element, and the photosensitive element basically consists of photosensitive silver halide, Akebono silver salt, a reducing agent, and a dye-donating substance. , a binder.

In the former black and white type, optical information is given to the photosensitive silver halide through image exposure, and during thermal development,
The photosensitive silver halide in the photosensitive layer and the reducing agent cause an oxidation-reduction reaction due to the catalytic action of the exposed photosensitive silver halide present in the vicinity, producing silver, and the exposed areas of the photosensitive layer become black. A silver image is formed.

In addition, in the color type, optical information is given to the photosensitive silver halide by image exposure, and during thermal development, the optical information is transferred between the organic silver salt and the photosensitive silver halide under the action of a reducing agent. Dissolution physical development was performed and worked,
Alternatively, the dye that forms the image is released or formed by the reaction of the reducing agent that has not acted with the dye-providing substance. The image-forming dye obtained by thermal development is transferred to an image-receiving element to form an image.

In order to take advantage of the characteristics of heat-developable photosensitive materials, which basically do not have the complication of the wet processing described above, shortening of the time required to obtain an image is being studied from various viewpoints.

In addition, in terms of developing applications for heat-developable photosensitive materials, the exposure method is also LE.
Attempts have also been made to use light sources such as D, CRT, FOD, and semiconductor lasers.

Therefore, it is possible to develop a photothermographic material that has high sensitivity, which is effective for shortening image formation time, and also provides stable photographic properties even during high-intensity exposure, which is aimed at shortening exposure time using the various exposure means mentioned above. Development is urgent.

In general, increasing the sensitivity of silver halide photosensitive materials is possible by increasing the content of silver iodide in the photosensitive silver halide used, but compared to silver halide photosensitive materials used in wet methods, In heat-developable photosensitive materials, unexpectedly large amounts of fog occur. This is well known as thermal fog caused by thermal development processing.

On the other hand, it is possible to use a thermal antifoggant that reduces thermal fog, and examples of this thermal antifoggant include:
Mercury compounds of U.S. Pat. No. 3,589.903, N-halogen compounds of U.S. Pat. No. 2,402,161, peroxides of U.S. Pat. No. 2,500,508, and Peroxides of U.S. Pat. No. 2,617.9.
No. 01 Sulfur Compound, U.S. Pat. No. 4,102,312
Palladium compounds of No. 53-28417, sulfinic acids of Japanese Patent Publication No. 53-28417, Research Disclosure No. 1
69077, mercaptotriazole of 169079, 1.2.4-triazole of US Pat. No. 4.137.079, and the like.

However, these thermal antifoggants are either extremely harmful to the human body or have little antifogging effect, and the reality is that no satisfactory thermal antifoggant has yet been found.

In addition, as a heat-developable photosensitive material with high sensitivity and improved thermal fog, a core/shell type photosensitive silver halide silver halide grain consisting of a core containing a high silver iodide content and a shell containing a low silver iodide content is used. The material used was filed in a patent application in 1986 by the present inventors.
Although it has been proposed in Japanese Patent Application No. 215948, it is still insufficient, especially in terms of thermal fog, and further improvements have been desired.

As a result of investigation using the above methods, it was discovered that a heat-developable photosensitive material containing a specific core/shell type photosensitive silver halide grain satisfies the above characteristics, leading to the present invention.

[Object of the Invention] Therefore, an object of the present invention is to provide a photothermographic material which has high sensitivity, particularly low thermal fog, and excellent high-intensity reciprocity law failure characteristics.

[Structure of the Invention] The above object of the present invention is to reduce iodine in the outermost layer of the outer shell of a core/shell type photosensitive silver halide grain consisting of an inner core and an outer shell covering the inner core. A heat developable material containing core/shell type photosensitive silver halide grains having a high iodine content of 10 mol% or less and a phase having a high iodine content in the outer shell, which has a higher iodine content than the outermost layer by 6 mol% or more. This is accomplished using photosensitive materials.

[Specific Structure of the Invention] The core/shell type photosensitive silver halide grains used in the present invention have an iodine content of 4 mol % to 40 mol % in the entire grain.
The iodine content is preferably 4% by mole, more preferably 4% by mole.
It is mol% to 20 mol%.

If the iodine content is less than 4 mol%, the thermal capri will be small, but disadvantages such as low photographic sensitivity will appear, and if the iodine content exceeds 40 mol%, the iodine in the silver halide grains will be reduced. There are disadvantages such as difficulty in obtaining a uniform crystal containing m, large thermal capacitance, and deterioration of high-intensity reciprocity law failure characteristics.

The core, ie, the internal core, of the core/shell type photosensitive silver halide grains used in the present invention preferably consists essentially of silver bromide or silver iodobromide. Here, "substantially silver bromide" means that the silver halide composition of the photosensitive silver halide grains basically consists of only silver bromide, but silver chloride, silver iodide, etc. are usually added in negligible amounts (for example, 2 mol). % or less). Substantially, silver iodobromide means that the silver halide composition of photosensitive silver halide grains basically consists of only iodide and silver bromide, but silver chloride etc. can usually be ignored (for example, 2
(mol% or less) is also included.

In the silver halide composition of the inner core of the core/shell type photosensitive silver halide grains of the present invention, the iodine content is from 0 mol% to
40 mol% is preferable, more preferably 0 mol% to 12
mol%, more preferably 0 mol% to 6 mol%
It is. The particle size of the inner core is preferably 0.05 μm to 0.8 μm, more preferably 0.05 μm to 0.4 μm.

The shell, that is, the outer shell of the core/shell type photosensitive silver halide grains used in the present invention preferably consists essentially of silver bromide or silver iodobromide, and the iodine content of the outermost layer of the outer shell is The outer shell has a high iodine content phase (hereinafter referred to as a high iodine content phase) of 10 mol % or less and a higher iodine content than the outermost layer by 6 mol % or more. Here, "substantially silver bromide" and "substantially silver iodobromide" have the same meanings as defined in the above-mentioned inner core.

The iodine content of the high iodine-containing phase is 6 mol% to 40 mol%.
is preferable, more preferably 10 mol% to 40 mol%
It is.

The volume of the high iodine-containing phase is 10 to 8 of the total silver halide grain.
It is preferably 0%, more preferably 20% to
It is 50%. The volume of the outermost layer is 4% to 70% of the entire particle.
It is preferable that the amount is 10% to 50%.
It is.

The high iodine content phase in the outer shell is a portion with an iodine content higher than the outermost layer provided between the outermost layer and the inner core by 6 mol% or more, and there is no restriction on the form of the phase. Even if a layer is formed, the iodine content may be gradually increased or decreased, and a portion of the layer may form a high iodine-containing phase.

Further, in the high iodine containing phase in the outer shell, a high iodine containing phase and another layer may be formed between the outermost layer of the outer shell and the high iodine containing phase, or between the inner core and the high iodine containing phase. Alternatively, an intermediate phase having an iodine content intermediate to that of the core may be provided.

The intermediate phase may have a uniform composition, may be a phase in which the composition changes in a stave-like manner, may be a phase in which the composition changes continuously, or may be a combination thereof. .

The volume of the intermediate phase is 5 to 60% of the total silver halide grains.
%, more preferably 10 to 50%.

The grain size distribution of the core/shell type photosensitive silver halide grains used in the present invention is preferably a monodisperse emulsion with a coefficient of variation of 20% or less, more preferably a coefficient of variation of 15%.
The following should be used. Core used in this modified invention/
The average grain size of shell-type photosensitive silver halide grains is 0.01
μm to 3.0 μm is preferable, more preferably 0.05 μm
It is μ11 to 2.0 μm.

In addition, its shape is cubic, spherical, flat plate, octahedron, 1
It may be a dihedral, a tetradecahedron, etc. that has a clear crystal habit, or it may not be a crystal habit.

The inner core of the core/shell type photosensitive silver halide grains of the present invention is formed by Glafkid-es
), Chimé Fitzk Photography (Chim
ie et Physique Photogra
pMque ) (Paul MOnt
el )sha, 1967), C.F. Tuffin (
Photographic Emulsion Chemistry (Photographic Emu)
(The Focal Press)
S) Published, 1966), Uie) Lt-Se')'y
Making and Coating J Photographic Imulsion (V, L, Z-elikman) et al.
Photographic [:mulsion)
(The Focal Press
It can be prepared using the method described in (Press), 1964). That is, any of the acidic method, neutral method, ammonia method, etc. may be used, and the method for reacting the soluble silver salt and soluble halogen salt may be any one-sided mixing method, simultaneous mixing method, or a combination thereof. .

It is also possible to use a method in which particles are formed in an excess of silver ions (so-called back-mixing method). pAg in the liquid phase in which silver halide is produced as a form of simultaneous mixing method.
The method of keeping constant is the so-called chondral
A double jet method can also be used. According to this method, a silver halide emulsion having a regular crystal shape and a nearly uniform grain size can be obtained.

Although two or more types of silver halide emulsions formed separately may be used as a mixture, it is preferable to use the double jet method or the Chondrold double jet method.

IIAII+ when preparing the inner core varies depending on the reaction temperature and the type of silver halide solvent, but is preferably 2 to 11. Further, it is preferable to use a silver halide solvent because the grain formation time can be shortened. For example, commonly known silver halide solvents such as ammonia and thioether can be used.

The shape of the internal core may be plate-like, spherical, twin-crystalline, or octahedral, cubic, dodecahedral, etc.

A tetradecahedron or a mixed system can also be used.

In addition, to make the particle size uniform, British Patent No. 1, 53
No. 5.016, Special Publication No. 48-36890, No. 52-1
As described in No. 6364, there is a method of changing the addition rate of silver nitrate or aqueous alkali halide solution depending on the grain growth rate, and as described in U.S. Pat. It is preferable to use a method of changing the aqueous solution concentration as described above to grow quickly within a range that does not exceed the critical saturation level.

These methods do not cause re-nucleation and each silver halide grain is uniformly coated, and are therefore preferably used when introducing a high iodine-containing phase, intermediate phase, or outermost layer.

In addition, as a method for newly coating the inner core with silver halide that will become the outer shell, for example, a method of simultaneously adding a halide aqueous solution and a silver nitrate aqueous solution, that is, a simultaneous mixing method;
This can be done by the Chondrold double jet method. For details, see Japanese Patent Application Laid-Open No. 53-22408,
Japanese Patent Publication No. 43-13162, Japanese Patent Publication No. 58-1482
No. 9, Journal of Photographic Science
hic5science) 24. 198 (197G
), etc.

The pAg when forming a high iodine-containing phase varies depending on the reaction temperature and the type and m of the silver halide solvent.
For example, when ammonia is used as a solvent, the number is preferably 7 to 11.

As a method for forming a high iodine-containing phase, a simultaneous mixing method or a Chondrald double jet method is more preferable.

The intermediate phase of the core/shell type photosensitive silver halide grains of the present invention is formed on the outside of the grain containing the inner core or on the outside having a high iodine-containing phase on the surface. It can be provided by a method of simultaneously mixing silver halides of different halogen compositions or coating by a Chondrald double jet method.

Regarding these methods, the method of providing a high iodine-containing phase described above is similarly used. The outermost layer of the core/shell type photosensitive silver halide grains of the present invention has a high iodine composition on the outside of the grain including an intermediate phase, a high iodine-containing phase, and an internal core. Silver halide having a halogen composition that is 6 mol % or more lower than the iodine content of the iodine-containing phase can be provided by a simultaneous mixing method or a Chondrald double jet method. For information on these methods,
The method of providing a high iodine-containing phase described above can be similarly used.

Regarding the iodine content m of the outermost layer of the core/shell type photosensitive silver halide grains of the present invention, for example, J.

■, Goldstein, D
,B.

U-1' IJ 7ms (Williams) r
"X-ray analysis in TEM/ATEM" scanning
Electron Microscopy (1977), No. 1
It can also be determined by the method described in Vol. I IT Research Institute, p. 651 (March 1977).

In the present invention, the average grain size of core/shell type photosensitive silver halide grains refers to the diameter in the case of spherical silver halide grains, and the projected image in the case of grains having shapes other than cubic or spherical. It is the average value of the diameter when converted into a circular image of the same area, and when the individual grain size is ri and the number is ni, do is defined by the following formula.

Note that the particle size can be measured by various methods commonly used in the technical field for the above purpose. A typical method is Loveland's [Particle Size Analysis Method JA, S.

T.M., Symposium on Light Microscopy, 1955, pp. 94-122, or Chapter 2 of [Theory of the Photographic Process], by Mies and James, 3rd edition, published by Macmillan (1966). ing.

The particle size can be measured using the projected area or approximate diameter of the particle.

If the particles are of substantially uniform shape, the particle size distribution can be expressed fairly accurately as diameter or projected area.

The silver halide emulsion containing core/shell type photosensitive silver halide grains used in the present invention (hereinafter also simply referred to as the silver halide emulsion of the present invention) can be chemically amplified by any method in the field of photographic technology. I can feel it. Such sensitization methods include, for example, gold sensitization, sulfur sensitization, gold-sulfur sensitization,
Various methods such as reduction sensitization can be used.

The photosensitive silver halide containing the core/shell type photosensitive silver halide grains used in the present invention has 1r of support per layer.
d is preferably 0.001 g to 50 g, more preferably 0.117 to IOg.

The heat-developable photosensitive material of the present invention includes each layer sensitive to blue light, green light, and red light using the silver halide emulsion of the present invention, namely, a heat-developable blue-sensitive layer, a heat-developable green-sensitive layer, and a heat-developable green-sensitive layer. It is also possible to have a multilayer structure as the development red-sensitive layer. In addition, two or more photosensitive layers of the same color (for example, a high-sensitivity layer and a low-sensitivity layer)
It can also be divided into two.

In the above case, the blue-sensitive silver halide emulsion, green-sensitive silver halide emulsion, and red-sensitive silver halide emulsion used, respectively, can be obtained by adding various spectral sensitizing dyes to the silver halide emulsion. I can do it.

Typical spectral sensitizing dyes used in the present invention include, for example, cyanine, merocyanine, complex (trinuclear or tetranuclear) cyanine, holopolar cyanine, styryl, hemicyanine, oxonol, etc. Cyanine dyes Among them, those with basic nuclei such as thiazoline, oxazoline, viroline, pyridine, oxazole 1, thiazole, selenazole, and imidazole are
More preferred. Such a nucleus may contain an alkyl group, an alkylene group, a hydroxyalkyl group, a sulfoalkyl group, a carboxyalkyl group, an aminoalkyl group, or an enamine group capable of forming a fused carbocyclic or heterocyclic ring. good. Further, it may be symmetrical or asymmetrical, and the methine chain or polymethine chain may have an alkyl group, a phenyl group, an enamine group, or a heterocyclic substituent.

In addition to the above-mentioned basic nucleus, merocyanine dyes may have acidic nuclei such as thiohydantoin nucleus, rhodanine nucleus, oxazolidione nucleus, thiazolidinedione nucleus, barbyric acid solution, thiazolinthione nucleus, malononitrile nucleus, and pyrazolone nucleus. good.

These acidic nuclei may be further substituted with an alkyl group, an alkylene group, a phenyl group, a carboxyalkyl group, a sulfoalkyl group, a hydroxyalkyl group, an alkoxyalkyl group, an alkylamine group or a heterocyclic nucleus. If necessary, these dyes may be used in combination.

Furthermore, ascorbic derivatives, azaindene cadmium salts, organic sulfonic acids, etc., such as U.S. Pat. No. 2,933,3
A supersensitizing additive that does not absorb visible light, such as those described in the specifications of No. 90 and No. 2.937.089, can be used in combination.

The amount of these sensitizing dyes to be added is 1 x 10-4 mol to 1 mol per mol of photosensitive silver halide in the silver halide emulsion of the present invention.
molar is preferred, more preferably i x i O-4
moles -1×10” moles.

The heat-developable photosensitive material of the present invention can be applied to any photosensitive material that forms an image by heat development.

For example, there are black and white types that form a silver image by heat development, and color types that include a dye-providing substance. In this latter color type, further monochromatic, e.g., monochromatic, with a black dye-donor or any other monochromatic dye-donor; polychromatic, e.g.
Examples include heat-developable color photosensitive materials that develop yellow, cyan, and magenta colors. In the color type, a method is usually used in which only the developed dye is transferred to the image receiving member.

The present invention exhibits particularly favorable effects when applied to the latter color type.

When the photothermographic material of the present invention is a black-and-white type in which a silver image is formed, (4) an organic silver salt is basically contained in the photosensitive material on the support as required.

In addition, in a color type that forms a dye image, basically one photosensitive layer on a support contains (1) the core/shell type photosensitive silver halide of the present invention, (2) a reducing agent, (3)
) a binder and (5) a dye-providing substance, and optionally (4) an organic silver salt. However, these do not necessarily need to be contained in a single photographic constituent layer; for example, the heat-developable photosensitive layer may be divided into two layers, and the components (1), (2), (3), and (4) may be added to the photothermographic layer. The dye-providing substance (5) is contained in the heat-developable photosensitive layer on one side, and the dye-providing substance (5) is contained in the layer on the other side adjacent to this photosensitive layer.

If they are in a state where they can react with each other, they may be contained separately in two or more constituent layers.

Further, the heat-developable photosensitive layer may be divided into two or more layers: a high-sensitivity layer and a low-sensitivity layer, a high-density layer and a low-density layer, or more.

The photothermographic material of the present invention has one or more photothermographic layers on a support. In the case of color, it generally has three heat-developable photosensitive layers with different color sensitivities, and in each photosensitive layer, dyes with different hues are formed or released by heat development.

Usually, a yellow dye is used in the blue-sensitive layer, a magenta dye is used in the green-sensitive layer, and a cyan dye is used in the red-sensitive layer, but the combination is not limited to these. It is also possible to combine a near-infrared sensitive layer.

The structure of each layer can be arbitrarily selected depending on the purpose. For example, a structure in which a red-sensitive layer, a green-sensitive layer, and a blue-sensitive layer are sequentially formed on the support, or a structure in which a blue-sensitive layer is sequentially formed on the support. There is a structure in which a photosensitive layer, a green photosensitive layer, and a red photosensitive layer are formed, or a structure in which a green photosensitive layer, a red photosensitive layer, and a blue photosensitive layer are sequentially formed on the support.

In addition to the heat-developable photosensitive layer, the heat-developable photosensitive material of the present invention can be provided with non-photosensitive layers such as an undercoat layer, an intermediate layer, a protective layer, a filter layer, a backing layer, and a release layer. To coat the heat-developable photosensitive layer and these non-photosensitive layers on the support, a method similar to that used for coating and preparing general silver halide photosensitive materials can be applied.

Namely, dip method, roller method, reverse roll method, air knife method, doctor blade method, spray method,
There are methods and equipment such as the bead method, extrusion method, stretch flow method, and curtain method.

In the heat-developable photosensitive material of the present invention, various silver salts can be used, if necessary, for the purpose of increasing sensitivity and improving developability.

The organic silver salts used in the heat-developable photosensitive material of the present invention include Japanese Patent Publication Nos. 43-4921 and 49-521326.
No. 52-141222, No. 53-36224, and No. 53-37610, as well as U.S. Patent No. 3.330.633, U.S. Patent No. 3,794,496,
Silver salts of long-chain aliphatic carboxylic acids and silver salts of carboxylic acids having heterocycles, such as silver laurate and silver myristate, as described in the specifications of No. 4,105.451, etc. , silver balmitate, silver stearate, silver arachidonate, silver behenate, silver α-(1-phenyltetrazolthio)acetate, etc., silver aromatic carboxylates, such as silver benzoate, silver phthalate, etc. No. 26582, No. 45-12700, No. 45-18416, No. 45-
No. 22185, JP-A-52-137321, JP-A-5
There are silver salts of imino groups described in publications such as No. 8-118638, No. 58-118639, and U.S. Pat. No. 4.123.274.

Examples of silver salts of imino groups include benztriazole silver. The penztriazole silver may be substituted or unsubstituted. Representative examples of substituted benztriazole silver include, for example, alkyl-substituted benztriazole silver (preferably an alkyl group of 022 or less,
More preferably those substituted with an alkyl group of C+ or less, such as methylbenztriazole silver, ethylbenztriazole silver, n-octylbenztriazole silver, etc.), alkylamidobenztriazole silver (preferably substituted with an alkylamide group of 022 or less) silver acetamidobenztriazole, silver propionamidebenztriazole, silver 1so-butylamidebenztriazole, silver laurylamidebenztriazole, etc.), silver alkylsulfamoylbenztriazole (preferably alkylsulfamoyl of 022 or less) those substituted with groups, such as 4-(N,N-diethyls,
rufamoyl)penztriazole silver, 4-(N-propylsulfamoyl)penztriazole silver, 4-(N
-octylsulfamoyl)penztriazole silver, 4
-(N-decylsulfamoyl)penztriazole silver, 5-(N-octylsulfamoyl)penztriazole silver, etc.), silver salts of halogen-substituted benztriazoles (such as 5-chlorobenztriazole silver, 5-bromobenztriazole silver), triazole silver, etc.), alkoxybenztriazole silver (preferably substituted with a C22 or less alkoxy group, more preferably a C22 or less alkoxy group, such as 5-methoxybenztriazole silver, 5-ethoxybenztriazole silver, etc.), 5 -Silver nitrobenztriazole, silver 5-aminobenztriazole, silver 4-hydroxybenztriazole, silver 5-carboxybenztriazole, silver 4-sulfobenztriazole, 5
-silver sulfobenztriazole, and the like.

Examples of other silver salts having an imino group include imidazole silver, benzimidazole silver, 6-nidropenzimidazole silver, pyrazole silver, urazole silver, 1.2
．． Silver 4-triazole, silver 1-tetrazole, silver 3-amino-5-benzylthio-1,2,4-triazole, silver saccharin, silver phthalazinone, silver phthalimide, and other silver salts of mercapto compounds, such as 2-mercapto. Silver benzoxazole, silver mercaptooxadiazole, silver 2-mercaptobenzothiazole, silver 2-mercaptobenzimidazole, silver 3-mercapto-4-phenyl-1,2,4-triazole, 4-hydroxy-6
-Methyl-1,3゜3a, 7-chitrazaindene silver and 5-methyl-7-hydroxy-1,2,3,4,6-
Examples include silver pentazaindene.

Other silver complex compounds with a stability constant of 4.5-10.0 as described in JP-A No. 52-31728, and imidase as described in U.S. Pat. No. 4,168,980. A silver salt of lynchion or the like is used.

Among the above organic silver salts, imino group silver salts are preferred;
Particularly preferred are silver salts of benzotriazole derivatives, more preferably 5-methylbenzotriazole and its derivatives, sulfobenzotriazole and its derivatives, and N-alkylsulfamoylbenzotriazole and its derivatives.

The organic silver salts used in the present invention may be used alone or in combination of two or more. Further, a silver salt may be prepared as vA in a suitable binder and used as it is without isolation, or the isolated product may be dispersed in a binder by an appropriate means and used. Dispersion methods include, but are not limited to, ball mills, sand mills, colloid mills, vibration mills, and the like.

In addition, the method for preparing organic silver salts is generally to dissolve silver nitrate and raw organic compounds in water or an organic solvent and mix them, but if necessary, a binder may be added or a solution such as sodium hydroxide may be added. It is also effective to add an alkali to promote dissolution of organic compounds, or to use an ammoniacal silver nitrate solution.

The amount of the organic silver salt used is generally preferably 0.01 to 500 mol, more preferably 0.1 to 100 mol, per 1 mol of photosensitive silver halide. More preferably 0
．． It is 3 to 30 moles.

As the reducing agent used in the photothermographic material of the present invention, those commonly used in the field of photothermographic materials can be used.

The dye-providing substance used in the heat-developable photosensitive material of the present invention is, for example, JP-A-57-186744;
-79247, 58-149046, 58
-149047, 59-124339, 5
In the case of a dye-donating substance that releases or forms a diffusible dye by coupling with an oxidized form of a reducing agent as disclosed in No. 9-181345, Go-2950, etc., the present invention applies. Examples of reducing agents used in this process include, for example, US Pat.
, No. 270 and No. 3,764,328, as well as RD No. 12146 and No. 3,764,328.

15108, same No. 15127 and JP-A-1983-
Using p-phenylenediamine type and p-, aminophenol type developing agents, phosphoramide phenol type, sulfonamide phenol type developing agents, sulfonamide aniline type developing agents, hydrazone type color developing agents, etc. described in Japanese Patent No. 27132. I can do things. Also, U.S. Patent No. 3,342,599, U.S. Patent No. 3,719/,
No. 492, JP-A-53-135628, JP-A No. 57-79
Color developing agent precursors described in No. 035 and the like can also be advantageously used.

As a particularly preferable reducing agent, JP-A-56-146133
Examples include reducing agents represented by the following general formula (1) described in the No.

General formula (1) In the formula, R1 and R2 represent a hydrogen atom or an alkyl group having 1 to 30 carbon atoms (preferably 1 to 4) that may have a substituent, and R1 and R2 are ring-closed. May form a heterocycle. R3, R+.

R5 and R6 each have a hydrogen atom, a halogen atom, a hydroxy group, an amino group, an alkoxy group, an acylamido group, a sulfonamide group, an alkylsulfonamide group, or a carbon atom number of 1 to 30 (preferably 1 to 30) that may have a substituent. 4)
represents an alkyl group, and R3 and R1 and R5 and R2 may each be closed to form a heterocycle. M represents an alkali metal atom, an ammonium group, a nitrogen-containing organic base, or a compound containing a quaternary nitrogen atom.

The nitrogen-containing organic base in the above general formula (1) is an organic compound containing a basic nitrogen atom capable of forming a salt and a salt, and particularly important organic bases include amine compounds. Chain amine compounds include primary amines, secondary amines, tertiary amines, etc., and cyclic amine compounds include lysine, quinoline, piperidine, etc., which are well-known examples of typical heterocyclic organic bases. , imidazole and the like. In addition, compounds such as hydroxylamine, hydrazine, and amidine are also useful as quenching amines. In addition, as the salt of the nitrogen-containing organic base, inorganic acid salts of the organic base (eg, hydrochloride, sulfate, nitrate, etc.) as described above are preferably used.

On the other hand, examples of the compound containing quaternary nitrogen in the above general formula include salts or hydroxide compounds of nitrogen compounds having a 4rfJ covalent bond.

Below is a margin.Next, preferred specific examples of the reducing agent represented by the general formula (1) are shown below.

(R-5) H3 Ck'3 (R-20) (R-21) (R-23) (R-2r) (J-2 O) Cn-z'7) (R-2g') C';2-x'r) CR-30) The reducing agent represented by the above general formula (1) can be prepared by a known method,
For example, Houben Peil, Mesosden der Organitsien Hemi, Band XI/2 (Houben
-Weyl, Methoden der Oraan
ischen Chemie, Band X I
/2) It can be synthesized according to the method described on pages 645-703.

Furthermore, it is also possible to use two or more of the above-mentioned reducing agents at the same time, or to use a black and white developing agent described below in combination for the purpose of increasing developability.

Further, the dye-donating substance used in the present invention is JP-A No. 57-179840, No. 58-58543, No. 5
In the case of compounds that release dyes upon oxidation, compounds that lose their ability to release dyes when oxidized, compounds that release dyes when reduced, etc. as shown in Nos. 9-152440 and 59-154445, etc. Alternatively, in the case where only a silver image is simply obtained, a developing agent as described below can also be used.

For example, phenols (e.g. p-phenylphenol, p-methoxyphenol, 2,6-tert-
butyl-p-cresol, N-methyl-p-aminophenol, etc.), sulfonamidophenols [e.g. 4-
Benzenesulfonamidophenol, 2-benzenesulfonamidophenol, 2,6-dichloro-4-benzenesulfonamidophenol, 2,6-dipromo 4-
(+1-toluenesulfonamide)phenol, etc.], or polyhuman mixybenzenes (e.g., hydroquinone, tert-butylhydroquinone, 2,6-dimethylhydroquinone, chlorohydroquinone, carboxyhydroquinone, catechol, 3-carboxycatechol, etc.), naphthol (e.g. α-naphthol, β-naphthol, 4-aminonaphthol, 4-methoxynaphthol, etc.), hydroxybinaphthyls and methylene bisnaphthols [e.g. 1,1'-dihydroxy-2,2'
-binaphthyl, 6,6'-dibromo-2,2'-dihydroxy-1,1'-binaphthyl, 6,6-sinitro2,2'-dihydroxy-1,1'-binaphthyl, 4,
4'Fujimethoxy-1,1'-dihydroxy-2,2'
-binaphthyl, bis(2-hydroxy-1-naphthyl)
methane, etc.], methylene bisphenols [e.g. 1.1
-bis(2-hydroxy-3,5-dimethylphenyl)
-3゜5.5-trimethylhexane, 1.1-bis(2
-hydroxy-3-tert-butyl-5-methylphenyl)methane, 1,1-bis(2-hydroxy-3,5
-di-tert-butylphenyl)methane, 2,6-methylenebis(2-hydroxy-3-tert-butyl-
5-methylphenyl)-4-methylphenol, α-phenyl-α, α-bis(2-hydroxy-3-tert
-butyl-5-methylphenyl)methane, 1,1-bis(2-hydroxy-3,5-dimethylphenyl)-2-
Methylpropane, 1,1,5,5-tetrakis(2-hydroxy-3,5-dimethylphenyl)-2,4-ethylpentane, 2,2-bis(4-hydroxy-3,5-
dimethylphenyl)propane, 2,2-bis(4-hydroxy-3-methyl-5-tert-butylphenyl)
propane, 2,2-bis(4-hydroxy-3,5-di-tert-butylphenyl)propane, etc.], ascorbic acids, 3-pyrazolidones, pyrazolones, hydrazones, and paraphenylenediamines.

These developing agents mentioned above can also be used alone or in combination of two or more.

The amount of the reducing agent used in the heat-developable photosensitive material of the present invention depends on the type of photosensitive silver halide, the type of organic acid silver salt, and the type of other additives used, but usually is 0.01 per mole of photosensitive silver halide
-1500 mol, preferably 0.1-20
It is 0 mole.

The binders used in the heat-developable photosensitive material of the present invention include synthetic or natural binders such as polyvinyl butyral, polyvinyl acetate, ethyl cellulose, polymethyl methacrylate, cellulose acetate butyrate, polyvinyl alcohol, polyvinyl pyrrolidone, gelatin, and phthalated gelatin. One or more of these polymeric substances can be used in combination. In particular, it is preferable to use gelatin or a derivative thereof together with a hydrophilic polymer such as polyvinylpyrrolidone or polyvinyl alcohol, and more preferably the following binder described in JP-A-59-229556.

This binder includes gelatin and vinylpyrrolidone polymer. The vinyl pyrrolidone polymer may be polyvinyl pyrrolidone, which is a homopolymer of vinyl pyrrolidone, or a copolymer of vinyl pyrrolidone with one or more other monomers copolymerizable (including graft copolymers). ). These polymers can be used regardless of their degree of polymerization. Polyvinylpyrrolidone may be substituted polyvinylpyrrolidone, and preferred polyvinylpyrrolidone has a molecular weight of 1,000 to 4.
00,000. Other polymers that can be copolymerized with vinylpyrrolidone include (meth)acrylic acid esters such as acrylic acid, methacrylic acid and alkyl esters thereof, vinyl alcohols, vinyl acetates, vinyl imidazoles, and (meth)acrylamides. kind,
Examples include vinyl monomers such as vinyl carbinols and vinyl alkyl ethers, but it is preferable that polyvinylpyrrolidone accounts for at least 20% (weight %, same hereinafter) of the composition ratio. Preferred examples of such copolymers are those in which the molecule m is from s,ooo to 400,000.

The gelatin may be lime-treated or acid-treated, and may be ossein gelatin, big skin gelatin, hydrogelatin, or modified gelatin obtained by esterifying or phenylcarbamoylating these gelatins.

In the above binder, gelatin preferably accounts for 10 to 90% of the total binder amount, more preferably 20 to 60%, and vinylpyrrolidone accounts for 5 to 90%.
It is preferably 10 to 80%, more preferably 10 to 80%.

The binder may contain other polymeric substances,
Gelatin and a mixture of polyvinylpyrrolidone with a molecular weight of 1,000 to 400.000 and one or more other polymeric substances, gelatin and molecules m s, ooo to 400.0
A mixture of the vinylpyrrolidone copolymer No. 00 and one or more other polymeric substances is preferred. Other polymeric substances that can be used include polyvinyl alcohol, polyacrylamide, polymethacrylamide, polyvinyl butyral, polyethylene glycol, polyethylene glycol ester, or proteins such as cellulose derivatives,
Natural substances such as starch, polysaccharides such as gum arabic and the like can be mentioned. These range from 0 to 85%, preferably from 0 to 70%
% may be contained.

Note that the vinyl pyrrolidone polymer may be a crosslinked polymer, but in this case, it is preferable to crosslink it after coating it on the support (including the case where the crosslinking reaction progresses by leaving it to stand).

The amount of binder used is usually o, osg to 50 g per layer per 1vt of support, preferably 0.1g.
~10g.

In addition, the binder is 0.1% per 1g of the dye-providing substance.
It is preferable to use ~10g, more preferably 0.2
It is 5 to 4 g.

The support used in the heat-developable photosensitive material of the present invention is as follows:
For example, polyethylene film, cellulose acetate film and polyethylene terephthalate film, synthetic plastic films such as polyvinyl chloride, paper supports such as photographic base paper, printing paper, baryta paper and resin-coated paper, and electronic coatings on these supports. Examples include a support coated with a line-curable resin composition and cured.

Margins Below When the heat-developable photosensitive material of the present invention is used as a transfer type image-receiving member, various heat solvents are preferably added to the heat-developable photo-sensitive material and/or the image-receiving member. The thermal solvent used in the present invention is a compound that promotes thermal development and/or thermal transfer. Regarding these compounds, for example, U.S. Patent No. 3.347.675, U.S. Pat.
56, Japanese Patent Application No. 59-47787, etc., and those particularly useful in the present invention include urea derivatives (e.g., dimethylurea, diethylurea, phenylurea, etc.). ), amide derivatives (e.g. acetamide, benzamide, etc.),
Polyhydric alcohols (for example, 1,5-bentanediol, 1,6-bentanediol, 1,2-cyclohexanediol, pentaerythritol, trimethylolethane, etc.) or polyethylene glycols can be mentioned.

Among the above thermal solvents, water-insoluble solid thermal solvents described below are more preferably used.

A water-insoluble solid thermal solvent is a compound that is solid at room temperature but becomes liquid at high temperatures (60°C or higher, preferably 100°C or higher, particularly preferably 130°C or higher and 250°C or lower), and is an inorganic/organic compound. ratio (“Organic Conceptual Diagram” by Yoshio Koda,
Sankyo Shuppan ■, 1984) is in the range of 0.5 to 3.0, preferably 0.7 to 2.5, particularly preferably 1.0 to 2.0, and the solubility in water at room temperature is Refers to compounds smaller than 1.

Specific examples of water-insoluble solid thermal solvents are shown below, but the invention is not limited thereto.

Below are examples of water-insoluble solid thermal solvents C (CJ!,)3C0NH2141° 1.441
Many of the compounds used as the 68° water-insoluble solid heat solvent are commercially available, and can be easily synthesized by those skilled in the art.

The method of adding the water-insoluble hot solvent is not particularly limited, but it may be added by grinding and dispersing it using a ball mill, sand mill, etc.
There are methods such as adding it by dissolving it in an appropriate solvent, and adding it as an oil-in-water dispersion by dissolving it in a high boiling point solvent.
It is preferable to pulverize and disperse the solid particles using a ball mill, sand mill, etc. and add them while maintaining the solid particle shape.

Layers to which the water-insoluble solid thermal solvent is added include a photosensitive silver halide emulsion layer, an intermediate layer, a retention layer, an image receiving layer of an image receiving member, etc., and are added so as to obtain the respective effects.

The amount of the water-insoluble heat solvent added is usually 10% to 500% by weight, preferably 50% to 300% by weight of the binder amount.

Note that even when the melting point of the water-insoluble solid thermal solvent of the present invention is higher than the thermal development temperature, the melting point is lowered by being added to the binder, so that it can be effectively used as a thermal solvent.

The heat-developable photosensitive material of the present invention may contain various additives as required in addition to the above-mentioned components.

For example, melt formers such as acetamide and succinimide described in U.S. Pat. No. 3,438,776; compounds such as polyalkylene glycols described in U.S. Pat. No. 3,666,477 and JP-A-51-19525; , -C〇-1-3O2- described in U.S. Pat. No. 3,667,959
There are non-aqueous polar compounds having a melting point of 20° C. or higher, such as lactones having 1-80- groups.

Furthermore, benzophenone derivatives described in JP-A-49-115540, JP-A-53-24829 and JP-A-53-24829;
Phenol derivatives described in No. 60223, JP-A-5
Carboxylic acids described in No. 8-118640, polyhydric alcohols described in JP-A-58-198038,
Also included are sulfamoylamide compounds described in JP-A-59-84236.

Further, a color toning agent known in heat-developable photosensitive materials may be added as a development accelerator to the photothermographic material of the present invention. As a color toning agent, for example, JP-A-46-4
No. 928, No. 46-6077, No. 49-5019,
49-5020, 49-91215, 4
No. 9-101727, No. 50-2524, No. 50-
No. 67132, No. 50-67641, No. 50-11
No. 4217, No. 52-33722, No. 52-9981
No. 3, No. 53-1020, No. 53-55115, No. 53-76020, No. 53-125014, No. 54
-156523, 54-156524, 54
-156525, 54-156526, 55
-4060, 55-4061, 55-3201
No. 5, as well as West German Patent No. 2.140,406, West German Patent No. 2,141°063, West German Patent No. 2.220.618, US Patent No. 3.847.612, West German Patent No. 3,782,
No. 941, No. 4,201,582 and JP-A-57
-207244, 57-207245, 58-
Phthalazinone, phthalimide, pyrazolone, quinazolinone, N-hydroxynaphthalimide, benzoxazine, naphthoxazinedione, 2,3-dihydro-7-thalazinedione, which are compounds described in specifications such as No. 189628 and No. 58-193541. , 2,3-dihydro-1,3-oxazine-2,4-dione, oxypyridine, aminopyridine, hydroxyquinoline, aminoquinoline, isocarbostyryl, sulfonamide, 2
H-1,3-benzothiazine-2,4-(3H) dione, benzotriazine, mercaptotriazole, dimerkabutotetrazabentalene, aminomercaptotriazole, acylaminomercaptotriazoles, phthalic acid, naphthalic acid, phthalamic acid, etc. There is one of these
a mixture of one or more with an imidazole compound,
Also, mixtures of at least one acid or acid anhydride such as phthalic acid and naphthalic acid and a phthalazine compound, furthermore, phthalazine and maleic acid, itaconic acid, quinolinic acid,
Examples include combinations of gentisic acid and the like.

Examples of antifoggants include those described in US Pat. No. 3,645.
Higher aliphatic compounds (e.g. behenic acid, stearic acid, etc.) described in No. 739, mercuric salts described in Japanese Patent Publication No. 11113/1983, and N-
Halogen compounds (e.g. N-halogenoacetamide, N
-halogenosuccinimide, etc.), U.S. Patent No. 3,700
, 457, mercapto compound-releasing compounds described in JP-A No. 51-50725, arylsulfone M (e.g. benzenesulfonic acid, etc.) described in JP-A No. 49-125016, lithium carboxylate described in JP-A No. 51-47419. salts (e.g. lithium laurate), British Patent No. 1,45
5,271, oxidizing agents (e.g. perchlorates, inorganic peroxides, persulfates, etc.) described in JP-A-50-101,019, sulfinic acids or thiosulfonic acids described in JP-A-53-19825. , 2 described in No. 51-3223
-Thiouracils, simple sulfur described in No. 51-26019, disulfide and polysulfide compounds described in No. 51-42529, No. 51-81124, and No. 55-93149, rosin described in No. 51-57435, or Diterpenes (e.g. abietic acid, pimaric acid, etc.), polymeric acids having free carboxy or sulfonic acid groups as described in US Pat. No. 51-104338, thiazolinthione as described in US Pat. No. 54-51821, U.S. Patent No. 4,137,
1,2,4-triazole or 5 described in No. 079
-Mercapto-1,2,4-triazole, 55-1
Thiosulfinate esters described in No. 40833, 1.2.3.4-thiatriazoles described in No. 55-142331, No. 59-46641, No. 59-572
33, the dihalogen compounds or trihalogen compounds described in No. 59-57234, and furthermore, No. 59-111.
Examples include thiol compounds described in No. 636.

In addition, as other antifoggants, Japanese Patent Application No. 59-565
Hydroquinone derivatives described in No. 06 (for example, di-
t-octylhydroquinone, doorlyhydroquinone, etc.) and hydroquinone derivatives and benzotriazole derivatives (e.g., 4-
Sulfobenzotriazole, 5-carboxybenzotriazole, etc.) can be preferably used in combination.

As a silver image stabilizer, U.S. Pat. No. 3,707,37
Polyhalogenated MS-forming agents (e.g., tetrabromobutane, tribromoquinaridine, etc.) described in No. 7 Mei aS, 5-methoxycarbonylthio-1-phenyltetrazole described in Belgian Patent No. 768.071 , monohalo compounds described in JP-A-50-119624 (e.g., 2-proT-2-tolylsulfonylacetamide, etc.), bromine compounds described in JP-A-50-120328 (e.g., 2-bromomethylsulfonylbenzo thiazole, 2,4-bis(tribromomethyl)-6-methyltriazine, etc.), and tribromoethanol described in JP-A-53-46020. Also special IF [5
Various monohalogenated organic antifoggants for silver halide emulsions such as those described in No. 1-119624 can be used.

Other image stabilizers include US Pat. No. 3,220.
No. 846, No. 4,082,555, No. 4.088
．． 496, Japanese Unexamined Patent Publication No. 50-22625, Research Disclosure (RD) No. 12021, Research Disclosure (RD) No. 15168, No. 15567, No. 15732, No. 15733, No. 15734, No. 15776, etc. Compounds that release basic substances by heat, such as compounds such as guanidinium trichloroacetate that release basic substances by decarboxylation with heat, aldnamide compounds such as galactonamide, amine imides, and compounds such as 2-carboxycarboxamide; , JP-A-56-130745, JP-A No. 56-13
Sodium phosphate base generator described in No. 2332, compound generating amine by intramolecular nucleophilic reaction described in British Patent No. 2,079,480, JP-A-59-15
0 aldoxime carbamates described in No. 763γ, hydroxamic acid carbamates etc. described in No. 59-166943, and No. 59-180537, No. 59-1
Examples include base releasing agents described in No. 74830 and No. 59-195237.

Furthermore, U.S. Patent Nos. 3,301,678 and 3,506
, No. 444, No. 3.824.103, No. 3,844
．． Illithiuronium compounds, 3-rubamoyl derivatives of mercapto-containing compounds, and nitrogen-containing heterocyclic compounds described in RD No. 788, RD 12035, and RD 18016 may be used for the purpose of stabilizing images. Patent No. 3.669.670, Patent No. 4,012,260@,
No. 4,060,420, No. 4,207,392,
The activator stabilizer and activator stabilizer precursor described in RD 15109 and RD 17711, etc., are developed using a nitrogen-containing organic base such as the α-sulfonylacetic acid group of 2-aminothiazoline or trichloroacetate, and an acylhydrazine compound, respectively. It can be used for the purpose of promoting or for stabilizing the image.

Also, for example, JP-A-56-130745 and JP-A-59-2
Development may be carried out in the presence of a small amount of water as described in No. 18443, or water may be supplied by spraying a small amount of water or applying a certain amount of water before heating. 3.
312,550 and the like, development may be carried out using hot steam, hot air containing moisture, or the like. Compounds that release water into heat-developable photosensitive materials, such as Japanese Patent Publication No. 44-265
Compounds containing water of crystallization as described in No. 82, such as sodium phosphate dodecahydrate and ammonium alum ditetrahydrate, may be incorporated into the photothermographic material.

In addition, various additives such as antihalation dyes, optical brighteners, hardeners, antistatic agents, plasticizers, and spreading agents, coating aids, and the like may be used.

The heat-developable photosensitive material of the present invention includes a heat-developable photosensitive layer and/or a non-photosensitive layer (for example,
Colloidal silica can be used for the undercoat layer, intermediate layer, protective layer, etc.).

The colloidal silica used in the present invention is a colloidal solution of silicic anhydride with an average particle size of 3 to 120 mμ mainly using water as a dispersion medium, and the main component is 5iO2 (silicon dioxide).
It is. Regarding colloidal silica, for example, JP-A-56-109336, JP-A-53-123916, JP-A-5
It is described in No. 3-112732, No. 53-100226, etc. The amount of colloidal silica used is 0.05 to 0.05 to the binder of the layer to be mixed and coated in terms of dry weight ratio.
A range of 2.0 is preferred.

The heat-developable photosensitive material of the present invention includes a heat-developable photosensitive layer and/or a non-photosensitive layer (for example,
An organic fluoro compound can be used for the undercoat layer, intermediate layer, protective layer, etc.).

Regarding the organic fluoro compounds used in the present invention, US Pat.
No. 3,754,924, No. 3.775.126, No. 3,850,640, West German Patent Publication No. 1,942
, No. 665, No. 1, No. 961, No. 638, No. 2, 12
No. 4,262, British Patent No. 1.330.356, Belgian Patent No. 742,680 and JP-A-46-778
No. 1, No. 48-9715, No. 49-46733, No. 49-133023, No. 50-99529, No. 50
-11322, 50-160034, 51-4
No. 3131, No. 51-129229, No. 51-106
No. 419, No. 53-84712, No. 54-1113
No. 30, No. 56-109336, No. 59-3053
No. 6, No. 59-45441 and Special Publication No. 47-930
No. 3, No. 48-43130, No. 59-5887, etc., and these compounds can be preferably used.

The heat-developable photosensitive material of the present invention includes a heat-developable photosensitive layer and/or
Alternatively, an antistatic agent can be used in a non-photosensitive layer (for example, an undercoat layer, an intermediate layer, a protective layer, etc.).

As the antistatic agent used in the present invention, British Patent No. 1
, No. 466.600, Research Disclosure t-
(Research [)isclosure)
15840, 16258, 16630, U.S. Patent Nos. 2,327,828, 2,861,056, 3,206,312, 3.245.833,
No. 3,428,451, No. 3.775.126, No. 3.963.498, No. 4,025,342, No. 4,025,463, No. 4.025,691, No. 4 , No. 025,704, etc., and these can be preferably used.

The heat-developable photosensitive material of the present invention includes a heat-developable photosensitive layer and/or
Alternatively, an ultraviolet absorber can be used in the non-photosensitive FJ (eg, undercoat layer, intermediate layer, protective layer, etc.).

As the ultraviolet absorber used in the present invention, benzophenone compounds (for example, those described in JP-A-46-2784, U.S. Pat. No. 3,215,530, and U.S. Pat. No. 3,698,907), butadiene compounds (for example, , U.S. Patent No. 4
．． 045.229), 4-thiazolidone compounds (e.g., those described in U.S. Pat. No. 3,314,794 and U.S. Pat. No. 3,352,681), benzotriazole compounds substituted with an aryl group [ For example,
-10466, 41-1687, 42-26
No. 187, No. 44-29620, No. 48-41572
No., JP-A-54-95233, JP-A No. 57-142975
No. 3,253,921, U.S. Patent No. 3,533,
No. 794, No. 3,754,919, No. 3,794
, No. 493, No. 4.009,038, No. 4,220
, No. 711, No. 4,323,633, Research Disclosure
re ) 22519, benzoxidol compounds (e.g., U.S. Pat. No. 3,700.45
5), cinnamate ester compounds (e.g., U.S. Pat. No. 3,705,805, U.S. Pat. No. 3,707,3)
No. 15 and JP-A No. 52-49029). Additionally, U.S. Patent No. 3,499.7
62 and JP-A-54-48535 can also be used. UV-absorbing couplers (e.g. α
- Naphthol-based cyan dye-forming couplers) and ultraviolet-absorbing polymers (e.g., JP-A-58-111942
No. 178351, No. 181041, No. 59-1
No. 9945, No. 23344, and those described in the official gazette).

The heat-developable photosensitive material of the present invention includes a heat-developable photosensitive layer and/or
Alternatively, a hardening agent can be used in a non-photosensitive layer (for example, an undercoat layer, an intermediate protective layer, etc.).

Hardening agents used in the present invention include aldehyde-based and aziridine-based hardeners (for example, Pa Report 19,921, U.S. Patent No. 2,950.197, U.S. Patent No. 2.964.404).
No. 2,983,611, No. 3,271,17
Specifications of No. 5, Japanese Patent Publication No. 46-40898, Japanese Patent Application Publication No. 1973
No. 0-91315), isoxazole-based (e.g., those described in U.S. Pat. No. 331.609), epoxy-based (e.g., U.S. Pat. No. 3,0-91315),
47,394, West German Patent No. 1,085,663, British Patent No. 1,033,518, Japanese Patent Publication No. 1973
-35495), vinyl sulfone type (e.g. PB Report 19,920, West German Patent No. 1)
, No. 100,942, No. 2,337,412, No. 2,
No. 545,722, No. 2,635,518, No. 2,1
No. 42,308, No. 2,749,260, British Patent No. 1,251,091, Japanese Patent Application No. 45-54236, No. 48-110996, U.S. Patent No. 3,539,644
No. 3,490,911), acryloyl type (e.g., Japanese Patent Application No. 1983-27949)
No. 2, US Pat. No. 3,640,720), carbodiimides (e.g., US Pat.
No. 938,892, No. 4,043,818, No. 4,0
Specifications of No. 61.499, Japanese Patent Publication No. 46-38715, and Japanese Patent Application No. 15095-1983! 2,410), triazine series (for example, those described in West German Patent No. 2,410,
No. 973, No. 2,553.915, U.S. Patent No. 3゜3
No. 25,287, 1llll book of each name, JP-A-52-127
22), maleimide-based, acetylene-based, methanesulfonic acid ester-based, and N-methylol-based hardeners can be used alone or in combination. As a useful combination technique, for example, West German Patent No. 2,447
, No. 587, No. 2,505.746, No. 2,514,
No. 245, U.S. Patent No. 4,047,957, U.S. Patent No. 3,8
32,181, 3,840,370, each Mei 1B book, JP-A No. 48-43319, JP-A No. 50-63062,
Examples include combinations described in Japanese Patent Publication No. 52-127329 and Japanese Patent Publication No. 48-32364.

The heat-developable photosensitive material of the present invention includes a heat-developable photosensitive layer and/or
Alternatively, a polymer hardener can be used in a non-photosensitive layer (for example, an undercoat layer, an intermediate layer, a protective layer, etc.).

Examples of the polymeric hardening agent used in the present invention include polymers having aldehyde groups (e.g., acrolein copolymers, etc.) described in U.S. Pat. No. 3,396,029.
, U.S. Pat. No. 3,362,827, Research Disclosure No. 17333 (1978), etc., polymers having a dichlorotriazine group, and U.S. Pat. No. 3,623.
, 878, Research Disclosure No. 16725 (1978),
U.S. Patent No. 4,161,407, JP 54-650
Examples thereof include polymers having an active vinyl group or a group that can be a precursor thereof, as described in Japanese Patent Application Laid-Open No. 56-66841, and polymers having an active ester group as described in Japanese Patent Application Laid-open No. 56-66841.

In the heat-developable photosensitive material of the present invention, a polymer latex is used in the heat-developable photosensitive layer and/or the non-photosensitive layer (e.g., undercoat layer, intermediate layer, protective layer, etc.) for the purpose of improving the physical properties of the film. be able to.

Preferred specific examples of the polymer latex used in the present invention include polymethyl acrylate, polyethyl acrylate, polylobyl acrylate, a copolymer of ethyl acrylate and acrylic acid, a copolymer of vinylidene chloride and butyl acrylate, a copolymer of butyl acrylate and acrylic acid, Examples include copolymers of vinyl acetate and butyl acrylate, copolymers of vinyl acetate and ethyl acrylate, copolymers of ethyl acrylate and 2-acrylamide, and the like.

The preferred average particle size of polymer latex is 0.02 μ■
~0.2 μm. Polymer latex is used in a dry weight ratio of 0.0 to the binder of the layer to which it is added.
3 to 0.5 is preferred.

In the heat-developable photosensitive material of the present invention, various interfaces are added to the heat-developable photosensitive layer and/or the non-photosensitive layer (e.g., undercoat layer, intermediate layer, RI1 layer, etc.) for the purpose of improving coating properties. Activators can be used.

The surfactant used in the present invention may be any of anionic, cationic, amphoteric and nonionic surfactants.

Examples of anionic surfactants include alkylcarboxylic MHA, alkylsulfonekylbenzenesulfonates, alkylnaphthalenesulfonates, alkylsulfates, alkylphosphates, N-acyl-N-alkyltaurines, and sulfosuccinic acid. Those containing acidic groups such as carboxy groups, sulfo groups, phospho groups, sulfate ester groups, and phosphate ester groups, such as esters, sulfoalkyl polyoxyethylene alkylphenyl ethers, and polyoxyethylene alkyl phosphate esters. preferable.

Examples of cationic surfactants include alkylamine salts, aliphatic or aromatic quaternary ammonium salts,
Heterocyclic quaternary ammonium salts such as pyridinium and imidazolium, and phosphonium or sulfonium salts containing aliphatic or heterocyclic rings are preferred.

Preferred examples of the amphoteric surfactant include amino acids, aminoalkyl sulfonic acids, aminoalkyl sulfates or phosphoric esters, alkyl betaines, and amine oxides.

Examples of nonionic surfactants include saponin (steroid type), alkylene oxide derivatives (e.g. polyethylene glycol, polyethylene glycol/polypropylene glycol condensates, polyethylene glycol alkyl ethers or polyethylene glycol alkyl aryl ethers, polyethylene glycol esters). , polyethylene glycol sorbitan esters,
polyalkylene glycol alkylamines or amides, polyethylene oxide adducts of silicone),
Preferred are glycidol derivatives (eg, alkenylsuccinic acid polyglycerides, alkylphenol polyglycerides), fatty acid esters of polyhydric alcohols, alkyl esters of sugars, and the like.

The heat-developable photosensitive material of the present invention includes a heat-developable photosensitive layer and/or a non-photosensitive layer (for example, an undercoat layer, an intermediate layer, etc.) for the purpose of improving developability, improving image dye transferability, improving optical properties, etc. ,
(protective layer, etc.) may contain non-photosensitive silver halide grains.

The non-photosensitive silver halide grains used in the present invention include those having any silver halide composition such as silver chloride, silver bromide, silver iodide, silver iodobromide, silver chlorobromide, and silver chloroiodobromide. can be used. The preferred particle size of the non-photosensitive silver halide grains is about 0.3 μm or less.

In addition, the addition level is 0 in terms of silver amount relative to the added layer.
．． A range of 02 to 3 a/f is preferred.

The heat-developable photosensitive material of the present invention includes a heat-developable photosensitive layer and/or a non-photosensitive layer (undercoat layer,
(intermediate layer, protective layer, etc.), for example, JP-A-51-10433.
Vinyl polymers having carboxyl groups or sulfo groups as described in No. 8 can be included.

The amount of the vinyl polymer used is preferably in the range of 0.05 to 2.0 in terms of dry weight ratio to the binder of the layer to which it is added.

Margins Below When the heat-developable photosensitive material of the present invention is a color type, a dye-providing substance is used.

Dye-providing substances that can be used in the present invention will be explained below. The dye-donating substance may be any substance as long as it participates in the reduction reaction of the photosensitive silver halide and/or the organic silver salt used as necessary and can form or release a diffusible dye as a function of the reaction. Depending on their reaction form, negative-acting dye-donors act on a positive function (i.e., form a negative dye image when negative-working silver halide is used) and positive-acting substances act on a negative function. It can be classified as a dye-providing substance (that is, it forms a positive dye image when negative-working silver halide is used). Negative dye-donating substances are further classified as follows.

Margin below Releases a diffusible dye when oxidized Release type compound　　　Formation type compound Each dye-providing substance will be further explained.

Examples of the reducible dye-releasing compound include compounds represented by general formula (2).

General formula (2) % formula % In the formula, Car is a reducing substrate (so-called carrier) that is oxidized and releases a dye upon reduction of the photosensitive silver halide and/or the organic silver salt used as necessary. , Dy
e is a diffusible dye residue.

Specific examples of the above-mentioned reducing dye-releasing compounds include JP-A-57-179840, JP-A-58-116537, and JP-A No. 58-116537.
No. 9-60434, No. 59-65839, No. 59-7
No. 1046, No. 59-87450, No. 59-8873
No. 0, No. 59-123837, No. 59-165054
No., No. 59-165054, each memorandum, etc., and include, for example, the following compounds.

The following margins illustrate dye-donor substances OCr6Hs3(n) OCI6H33(n) OC16H33 QC,, H33 0C16H33 I C(CH3)! Q2 Below, as a reducing dye releasing compound according to the margin, for example, general formula (3)
Examples include compounds represented by: .

group or an amino group, and DVe has the same meaning as Dye shown in general formula (2). Specific examples of the above compounds are given in JP-A No. 5
No. 9-124329.

As a coupled dye-releasing compound, general formula (4) is used.
Examples include compounds represented by:

General formula (4) % formula % In the formula, CI) 1 is an organic group (so-called coupler residue) that can react with the oxidized form of the reducing agent to release a diffusible dye, and J is a divalent It is a bonding group, and the bond between C1ot and J is cleaved by reaction with the oxidized form of the reducing agent. n
l represents 0 or 1, and Dye has the same meaning as defined in general formula (2). In addition, CD+ is preferably substituted with various ballast groups in order to make the coupled dye-releasing compound non-diffusible, and the ballast group has 8 or more carbon atoms ( more preferably 12 or more) organic groups, or hydrophilic groups such as sulfo groups and carboxy groups, or 8 or more (more preferably 12 or more) carbon atoms and hydrophilic groups such as sulfo groups and carboxy groups. It is a group that both have. Another particularly preferred ballast group can include polymer chains.

Specific examples of the compound represented by the above general formula (4) include JP-A-57-186744 and JP-A-57-122596.
No. 57-160698, No. 59-174834, No. 57-224883, No. 59-159159,
It is described in the specification of No. 59-231540, and includes, for example, the following compounds.

As the coupling dye-forming compound, general formula (5) is used.
Examples include compounds represented by:

General formula (5) % formula %) In the formula, CI)2 is an organic group (so-called coupler residue) that can react with the oxidized form of the reducing agent (coupling reaction) to form a diffusive dye. , F represents a divalent bonding group, and B represents a ballast group.

The coupler residue represented by CD2 preferably has a molecular number of 100 or less for the sake of diffusivity of the dye formed.
More preferably it is 500 or less.

In addition, the ballast group is preferably the same as the ballast group defined in general formula (4), and especially has 8 or more (more preferably 12 or more) carbon atoms and a hydrophilic group such as a sulfo group or a carboxy group. A group having both groups is preferable, and a polymer chain is more preferable.

Coupling dye formation with this polymer chain.

As the type compound, a polymer having a repeating unit derived from a monomer represented by the general formula (6) is preferable.

General formula (6) CI)2→F-)-+Ymonme-1→Z±-Moshi) In the formula, CD2 and F are the same as those defined in general formula (5), and Y is alkylene 2 represents 0 or 1, 2 represents a divalent organic group, and L represents an ethylenically unsaturated group or a group having an ethylenically unsaturated group.

Specific examples of the coupled dye-forming compounds represented by general formulas (5) and (6) include
3394, No. 59-181345, No. 60-2950
No., Japanese Patent Application No. 59-179657, No. 59181604
No. 59-182506, No. 59-182507 @
It is described in each specification etc., and the following compounds are mentioned, for example.

Below margin OOH ■ Polymer M-1 X: 80 weight 1% y: 20 weight % M-2 Heavy'j & Chi M-5 C city H 8 NHCOCHz ■ H
More specifically, the coupler residue defined by I or CR2 is preferably a group represented by the following general formula.

General formula (7) General formula (8 General formula (9)
) General formula (10) General formula (11)
General formula (12) General formula (13)
General formula (14) General formula (15)
General formula (16) In the blank formula below, R7, R[l, R9 and R10 are each a hydrogen atom, a halogen atom, an alkyl group, a cycloalkyl group,
Aryl group, acyl group, alkyloxycarbonyl group,
Aryloxycarbonyl group, alkylsulfonyl group,
Arylsulfonyl group, carbamoyl group, sulfamoyl group, acyloxy group, amino group, alkoxy group, aryloxy group, cyano group, alkylsulfonyl group, arylsulfonyl group, ureido group, alkylthio group, arylthio group, carboxy group, sulfo group or hetero Represents a ring residue, which further includes a hydroxyl group, a carboxy group, a sulfo group, an alkoxy group, a cyan group, a nitro group, an alkyl group,
Aryl group, aryloxy group, acyloxy group, acyl group, sulfamoyl group, carbamoyl group, imide group,
It may be substituted with a halogen atom or the like.

These substituents are selected depending on the purpose of CI) 1 and CD2, and as mentioned above, in <Cp+, one of the substituents is preferably a ballast group, and in CD2, it is preferable to improve the diffusibility of the dye formed. In order to increase the molecular weight, it is preferable to select substituents so that the number of molecules is 700 or less, more preferably 500 or less.

As a positive dye-donating substance, for example, the following general formula (1
There is an oxidizable dye-releasing compound represented by 7).

General formula (17) In the formula, Wl represents a collection of atoms necessary to form a quinone ring (which may have a substituent on this ring),
R11 represents an alkyl group or a hydrogen atom, R13 represents an oxygen atom or r represents O or 1,
Dye has the same meaning as defined in general formula (2).

Specific examples of this compound are described in the specifications of JP-A-59-166954 and JP-A-59-154445, and include the following compounds.

The following general formula (18) is used as a positive dye-providing substance according to the margin below.
There are compounds that lose their dye-releasing ability when oxidized, such as the compound represented by:

General formula (18) In the formula, W2 represents a group +1 of atoms necessary to form a benzene ring (which may have a substituent on the ring), and R, r, E, and Dye are represented by the general formula ( It has the same meaning as defined in 17). Specific examples of this compound are described in the specifications of JP-A-59-124327 and JP-A-59-152440, and include the following compounds.

Margin below Exemplary dye-donor substances ■ OCH.

＠ In the margin below, as another positive dye-donor substance, the following general formula (
Examples include compounds represented by 19).

General formula (19) In the above formula, W2 % R'' and Dye are general formula (1
It has the same meaning as that established in 8).

Specific examples of this compound are described in JP-A-59-154445, etc., and include the following compounds.

In the margin below, exemplified dye-providing substances having general formulas (2), (3), (4), (17) (18)
) and (19), the residue of the diffusible dye represented by Dye will be explained in further detail. The residue of the diffusible dye preferably has a molecular weight of 800 or less, more preferably 600 or less, for the sake of the diffusibility of the dye;
Examples include residues such as azomethine dyes, anthraquinone dyes, naphthoquinone dyes, styryl dyes, nitro dyes, quinoline dyes, carbonyl dyes, and phthalocyanine dyes.

These residual dye bases may be in a temporary short-waveform form that can be multicolored during thermal development or transfer. In addition, these dye residues are used for the purpose of increasing the light resistance of images, for example, in JP-A [Li
? Chelatable dye residues described in No. 59-48765 and No. 59-124337 are also preferred.

These dye-providing substances may be used alone or in combination of two or more. The amount used is not limited, and depends on the type of dye-providing substance, whether it is used alone or in combination, or whether the photographic constituent layer of the light-sensitive material of the present invention is a single layer or a multilayer of two or more types. Although it may be determined accordingly, the amount used can be, for example, o, oosa to 50 g per 1f, preferably o, ig to l0CI.

The dye-providing substance used in the present invention can be incorporated into the photographic constituent layer of the heat-developable light-sensitive material using any method. tricresyl phosphate, etc.), and then subjected to ultrasonic dispersion, or dissolved in alkaline water or solution (e.g., 10% aqueous sodium hydroxide solution, etc.), and then treated with a mineral acid (e.g., hydrochloric acid or nitric acid, etc.). It can be used after being neutralized, or after being dispersed in a ball mill with an aqueous solution of an appropriate polymer (eg, gelatin, polyvinyl butyral, polyvinylpyrrolidone, etc.).

Margins Below The heat-developable photosensitive material of the present invention is preferably provided with a protective layer. Hereinafter, this will be referred to as the protective layer of the present invention.

Various additives used in the photographic field can be used in the protective layer of the present invention. The additives include various matting agents, colloidal silica, slipping agents, organic fluoro compounds (especially fluorosurfactants), antistatic agents, ultraviolet absorbers, high boiling point solvents, antioxidants, hydroquinone derivatives, Examples include polymer latex, surfactants (including polymeric surfactants), hardeners (including polymeric hardeners), organic silver salt particles, non-photosensitive silver halide particles, and the like.

The matting agent used in the protective layer 1[1i1 of the present invention is as follows:
They are fine particles of inorganic or organic substances that are incorporated into a heat-developable photosensitive material to increase the surface roughness of the photosensitive material and make it matte.

Methods of using matting agents to prevent adhesion that occurs during manufacturing, storage, and use of photosensitive materials, and to prevent static electricity caused by contact, friction, and peeling between materials of the same or different types are known in the art. It is well known. Specific examples of matting agents include silicon dioxide described in JP-A-50-46316, JP-A-53-7231, JP-A-58-66937,
Alkali-soluble matting agents such as alkyl methacrylate/methacrylic acid copolymers described in JP-A No. 60-8894, alkali-soluble polymers having anionic groups described in JP-A-58-166341, JP-A-58-145935 A combination of two or more types of fine particle powders with different Mohs hardnesses, a combination of oil droplets and fine particle powders as described in JP-A-58-147734, two types with different average particle sizes as described in JP-A-59-149356 Combination of the above spherical matting agents, JP-A-56-4
The combination of a fluorinated surfactant and a matting agent described in No. 4411, British Patent No. 1.055.713, U.S. Patent No. 1,939,213, U.S. Patent No. 2,221,873,
No. 2,268,662, No. 2,322,037, No. 2,376,005, No. 2,391,181, No. 2,701,245, No. 2,992,101, No. 3, No. 079,257, No. 3.262.782, No. 3,443,946, No. 3,516,832, No. 3
．． No. 539.344, No. 3,591,379, No. 539.344, No. 3,591,379, No.
Organic matting agents described in JP-A-49-106821 and JP-A-57-14835, etc.; West German Patent No. 2.529, 3;
No. 21, British Patent No. 760.775, British Patent No. 1,260,
No. 772, U.S. Patent No. 1,201,905, U.S. Patent No. 2,1
No. 92,241, No. 3.053.662, No. 3,06
No. 2,649, No. 3,257,206, No. 3,322
, No. 555, No. 3.353.958, No. 3.370.
No. 951, No. 3,411,907, No. 3,437
, No. 484, No. 3, No. 523.022, No. 3,615
, No. 554, No. 3,635,714, No. 3.769
．． No. 020, No. 4,021,245, No. 4,029,
Inorganic matting agents described in JP-A-46-7781, JP-A-49-106821, JP-A-5
No. 1-6017, No. 53-116143, No. 53
-100226, 57-14835, 57-8
No. 2832, No. 53-70426, No. 59-149
No. 357, Special Publication No. 57-9053 and EP-1
A matting agent having physical properties such as those described in Specification No. 07,378, etc. is preferably used.

In the protective layer of the present invention, the amount of the matting agent added is preferably 1001111/2.0 g per 11 tons, and more preferably 201 Ig to 1.0 g. The particle size of the matting agent is preferably 0.5 to 10 μm, more preferably 1.0 to 10 μm.
It is 6μI.

The matting agents may be used in combination of two or more.

Examples of the slipping agent used in the protective layer of the present invention include solid paraffin, oils and fats, surfactants, natural waxes, synthetic waxes, etc. Specifically, French Patent Nos. 2 and 1
No. 80,465, British Patent No. 955,061, No. 1,
No. 143,118, No. 1,270,578, No. 1,
No. 320.564, No. 1,320,757, JP-A-4
No. 9-5017, No. 51-141623, No. 54-1
No. 59221, No. 56-81841, Research Disclosure
e) 13969, ``U.S. Patent No. 1,263,7
No. 22, No. 2,588.765, No. 2,739,89
No. 1, No. 3,018.178, No. 3,042,52
No. 2, No. 3,080,317, No. 3, 082.08
No. 7, No. 3,121,060, No. 3,222,1
No. 78, No. 3,295,979, No. 3.489.56
No. 7, No. 3,516.832, No. 3,658,573
No. 3,679.411, No. 3,870.521, etc. can be preferably used.

The protective layer of the present invention contains a high boiling point organic solvent (for example, U.S. Pat. No. 2,322,027, U.S. Pat.
No. 533,514, No. 2,882,157, Special Publication No. 4
No. 6-23233, British Patent No. 958.441, 1
．． 222.753, U.S. Patent No. 2,353,262, U.S. Patent No. 3,676,142, U.S. Patent No. 3.700.454,
Esters (e.g. phthalates, phosphoric esters, fatty acid esters, etc.), amides (e.g. fatty acid amides, (sulfonic acid amide, etc.), ethers, alcohols, paraffins, etc. ) may contain oil droplets in which a water-insoluble oil compound is emulsified and dispersed. Furthermore, these oil droplets may contain photographic additives for various purposes.

As the binder used in the adhesive of the present invention, one or a combination of two or more synthetic or natural polymeric substances such as polyvinyl butyral, polyvinyl acetate, ethyl cellulose, polymethyl methacrylate, amide, gelatin, and phthalated gelatin are used. be able to.

In particular, gelatin (including gelatin derivatives), polyvinylpyrrolidone (preferably molecular weight 1,000-400,000), polyvinyl alcohol (molecular weight 1,000-400,000),
ioo, ooo are preferred) and polyoxazolines (
A binder having a molecular weight of 1,000 to 800,000 is preferable alone or in combination of two or more of these binders,
Particularly preferred is a binder containing gelatin alone or a combination of gelatin and a hydrophilic polymer having good compatibility with gelatin, such as the above-mentioned polyvinylpyrrolidone, polyvinyl alcohol, and polyoxazoline. Gelatin may be treated with lime, acid, or ion exchange, and may be ossein gelatin, big skin gelatin, hydrogelatin, or modified gelatin obtained by esterifying or phenylcarbamoylating these gelatins.

The film thickness of the protective ff1li of the present invention is 0.05 to 5 μm.
is preferable, and more preferably 0.1 to 1.0 μm. Protect! ! m may be a single layer or may be composed of two or more layers.

Further, in order to increase film strength and prevent film destruction, it is also preferable that the hardness of the protective layer is greater than that of the photosensitive layer. One way to make the hardness of the protective layer higher than that of the photosensitive layer, that is, to control the hardness of each layer, is to use a diffusion-resistant hardener. By using it in the protective layer, only the degree of hardness of the protective layer can be made greater than that of the photosensitive layer. Polymer hardeners are known as diffusion-resistant hardeners.
For example, U.S. Patent No. 3.057.723, U.S. Pat.
No. 029, No. 4,181,407, JP-A-58-50
Hardeners described in No. 528 and the like can be used.

Another way to control the degree of dura for each layer is to
By containing a diffusible hardening agent (for example, a vinyl sulfone hardening agent) only in the protective layer, or by making the protective layer contain more than the photosensitive layer and rapidly drying after simultaneous multilayer coating, The degree of hardness of the protective layer can be greater than that of the photosensitive layer.

The following margins The heat-developable photosensitive material of the present invention is usually heated to a temperature of 80°C to 20°C after exposure to light.
1 at a temperature range of 0°C, preferably 100°C to 170°C.
Developing can be carried out by simply heating for 1.5 seconds to 120 seconds, preferably 1.5 seconds to 120 seconds. The transfer of the diffusible dye to the image-receiving layer may be carried out simultaneously with heat development by bringing the image-receiving member into close contact with the photosensitive surface of the photosensitive material and the image-receiving layer during heat development;
The image may be transferred by being brought into close contact with an image receiving member after thermal development and heated, or by being brought into close contact with an image receiving member after supplying water and further heated if necessary. Also, before exposure, 70℃~180℃
Preheating may be performed within the temperature range of . Also, JP-A-60
As described in Japanese Patent Application No. 143338 and Japanese Patent Application No. 60-3644, the photosensitive material and the image receiving member are preheated at a temperature of 80°C to 250°C immediately before thermal development transfer to improve mutual adhesion. Good too.

Various exposure means can be used for the photothermographic material according to the present invention. The latent image is obtained by imagewise exposure to radiation, including visible light. Generally, light sources used for ordinary color printing, such as tungsten lamps, mercury lamps, xenon lamps, laser beams, CRT beams, etc., can be used as the light source.

As the heating means, all methods applicable to ordinary heat-developable photosensitive materials can be used, such as contacting with a heated block or plate, contacting with a heated roller or drum, or passing through a high-temperature atmosphere. Alternatively, high-frequency heating may be used, or furthermore, a conductive layer containing a conductive substance such as carbon black may be provided on the back surface of the photosensitive material of the present invention or the back surface of the image receiving member for thermal transfer, and the Joule heat generated by energization may be utilized. You can also. There are no particular restrictions on the heating pattern, including methods of preheating (breheating) and then reheating, heating at a high temperature for a short time, or at a low temperature for a long time, continuously increasing, decreasing, or repeating, and even discontinuously. Although heating is possible, a simple pattern is preferred. Alternatively, a method in which exposure and heating proceed simultaneously may be used.

The image-receiving layer of the image-receiving member that can be effectively used in the present invention includes:
It is sufficient that it has the function of receiving the dye in the heat-developable photosensitive layer released or formed by heat development.
．． Those described in No. 709.690 are preferably used. For example, as a polymer containing an ammonium salt, the ratio of polystyrene-N,N,N-tri-0-hexyl-N-vinyl-benzylammonium chloride is 1:4 to 4:1, preferably 1:1. be.

Examples of polymers containing tertiary amines include polyvinylpyridine. A typical image-receiving layer for diffusion transfer is obtained by mixing a polymer containing ammonium salt, tertiary amine, etc. with gelatin, polyvinyl alcohol, etc., and coating the mixture on a support.

Another useful dye-receiving material is JP-A-57-2012
The glass transition temperature described in No. 50 etc. is 40°C or higher, 2
Examples include those formed of organic polymeric substances that are heat resistant to 50° C. or lower.

These polymers may be supported on a support as an image-receiving layer, or may themselves be used as a support.

Examples of the heat-resistant organic polymer substances include polystyrene, polystyrene derivatives 1 having a substituent having 4 or less carbon atoms, polyvinylcyclohexane, polydivinylbenzene, polyvinylpyrrolidone, polyvinylcarbazole polyvinyl alcohol, polyvinyl formal, and polyvinyl butyral. Polyacetals, polyvinyl chloride, chlorinated polyethylene, polytrichloride fluoroethylene, polyacrylonitrile, poly N,N-dimethylallylamide, p-cyanophenyl group, pentachlorophenyl group, and 2.

Polyacrylate with 4-dichlorophenyl group, polyacryl chloroacrylate, polymethyl methacrylate, polyethyl methacrylate, polypropyl methacrylate, polyisopropyl methacrylate, polyisobutyl methacrylate, poly-tert-butyl methacrylate, polycyclohexyl methacrylate, polyethylene glycol dimethacrylate , poly-2-cyano-
Polyesters such as ethyl methacrylate and polyethylene terephthalate, polysulfone, bisphenol A
Examples include polycarbonates such as polycarbonate, polyanhydrides, polyamides, and cellulose acetates.

In addition, Polymer Handbook Second Edition (G.A. Brandrup, E.H. Inmargatt II:) John Willy and Sons (Po'
Lymer Handbook 2nd ed.

L.J., Srandrup, E. H. I m
a+eraut edition) J ohn W iley & S
ons) published in 2013, the glass transition temperature is 40°C.
The following synthetic polymers are also useful. Generally, the molecular weight of the polymer substance is 2,000 to 200,00.
0 is useful. These polymeric substances may be used alone or in a blend of two or more types, or may be used in combination of two or more types as a copolymer.

Useful polymers include cellulose acetates such as triacetate and diacetate, polyamides in combinations such as hebutamethylene diamine and terephthalic acid, fluorene dipropylamine and adipic acid, hexamethylene diamine and diphenic acid, hexamethylene diamine and isophthalic acid, Examples include polyesters made of combinations of diethylene glycol and diphenylcarboxylic acid, bis-p-carboxyphenoxybutane and ethylene glycol, polyethylene terephthalate, and polycarbonates. These polymers may be modified. For example, polyethylene terephthalate using cyclohexane dimetatool, isophthalic acid, methoxypolyethylene glycol, 1,2-dicarbomethoxy4-benzenesulfonic acid, etc. as a modifier is also effective.

A particularly preferable image-receiving layer is JP-A-59-22342
Layer made of polyvinyl chloride described in No. 5 and JP-A-60
Examples include a layer made of polycarbonate and a plasticizer described in Japanese Patent No. 19138.

These polymers can also be used as a support and an image-receiving layer (image-receiving member), in which case the support may be formed from a single layer or from multiple layers. good.

As the support for the image-receiving member, any material such as a transparent support or an opaque support may be used. supports containing pigments such as titanium oxide, barium sulfate, calcium carbonate, and talc, baryta paper, paper laminated with thermoplastic resin containing pigments, cloth, glass, aluminum, etc. Metals, etc., supports on which an electron beam curable resin composition containing a pigment is coated and cured, and supports on which a coating layer containing a pigment is provided. etc.

In particular, a support that is coated with an electron beam curable resin composition containing a pigment on paper and cured, or a support that has a pigment coating layer directly on the paper or an electron beam curable resin composition on the pigment coating layer. The support coated with the composition and cured can be used as an image-receiving member as it is because the resin layer itself can be used as an image-receiving layer.

When the present invention is applied to a heat-developable color light-sensitive material, the various polymers mentioned above can be used as a mordant for a dye image and as an image-receiving layer. It may be an image-receiving element or the image-receiving layer may be a single layer that is part of a heat-developable color photographic material. If necessary, an opacifying layer (reflection layer) may be included in the light-sensitive material, such layer reflecting the desired degree of radiation, such as visible light, which can be used to observe the dye image in the image-receiving layer. It is used to make The opacifying layer (reflective layer) can contain various reagents that provide the necessary reflection, such as titanium dioxide.

The image-receiving layer of the image-receiving member can also be formed into a type that can be peeled off from the heat-developable photosensitive layer. For example, after imagewise exposure of a heat-developable color photosensitive material, an image-receiving layer can be superimposed on the heat-developable photosensitive layer and uniformly heat-developed. Further, after imagewise exposure and uniform heat development of the heat-developable color light-sensitive material, an image-receiving layer may be superimposed and heated at a temperature lower than the development temperature to transfer the dye image released or formed from the dye-providing substance.

Margins below [Specific Effects of the Invention] As explained above, in the present invention, by using specific core/shell type silver halide grains, it is possible to achieve high sensitivity and to effectively prevent thermal fog inherent to thermal development. Furthermore, we were able to provide a heat-developable photosensitive material with improved high-intensity reciprocity law failure characteristics.

[Specific Examples of the Invention] Hereinafter, the present invention will be specifically explained using Examples, but the embodiments of the present invention are not limited to these.

Example 1 A comparative emulsion was prepared by the method described below.

[Preparation of silver bromide emulsion] At 50°C, JP-A-57-92523;
Using the mixing agitator shown in the specification of No. 92524,
An aqueous solution (A) containing 20 g of ossein gelatin, distilled water 1000112 and ammonia, an aqueous solution 50011 containing 1.1 mol of potassium bromide, and an aqueous solution containing (B) solution of 1 mol of silver nitrate and ammonia. 5001 g of solution (C) was added at the same time while keeping the pAQ constant.

The shape and size of the emulsion grains to be prepared are determined by pH, EIA! The addition rates of liquids J, (B), and (C) were adjusted by controlling IIJ. A silver bromide emulsion was thus prepared.

The obtained silver halide grains were tetradecahedral grains with an average grain size of 0.3 μm and a monodispersity of 10%.

This emulsion was washed with water and desalted. The yield of emulsion was 8001 g.

[Preparation of silver iodobromide emulsions] Two types of photosensitive silver halide emulsions B1 and C having different silver iodide contents were prepared by the following method.

At 50°C, JP-A-57-92523, JP-A-57-92523;
Using the mixing agitator shown in the specification of No. 92524,
Potassium iodide and potassium bromide were added to solution (A) in which ossein gelatin 209, distilled water 1000 iQ, and ammonia were dissolved at specified concentrations (for emulsion B, potassium iodide 11.6+I
Emulsion C contains 33.2 g of potassium iodide and 120(7) potassium bromide.

Aqueous solution solution 5oo112 (B) and aqueous solution s o o 12 (C) containing 1 mol of silver nitrate and ammonia
I) The liquid was added at the same time while keeping the Ag constant. The shape and particle size of the emulsion grains to be prepared are determined by pH, pAa, B solution and C
Adjustments were made by controlling the rate of liquid addition.

In this way, emulsions having the same tetradecahedral shape but different silver iodide contents were prepared.

(The monodispersity of each emulsion was 12%.) Each of these emulsions was washed with water and desalted.

The outlet of each emulsion was 13001N.

The average grain size and silver iodide content of the silver halide emulsion thus prepared are shown in Table 1 below.

Table 1 [Preparation of core/shell type silver iodobromide emulsions] Two types of core/shell type emulsions having different silver iodide contents were prepared by the following method.

At 50°C, using the mixer shown above, add potassium iodide and potassium bromide to solution (A) in which 20 g of ossein gelatin, 100 hN of distilled water and ammonia were dissolved. Potassium iodide 11.61)
, 130 fJ of potassium bromide, 33.2 G of potassium iodide, 120 g of potassium bromide for Emulsion E) and 500 d of an aqueous solution (B) containing 1 mol of silver nitrate and 1 mol of ammonia. Liquid (C) was added at the same time while keeping the DAQ constant.The shape and size of the particles of the core emulsion to be prepared were determined by controlling 1) H, pAO, and the addition rate of liquids (B) and (C). Adjusted. In this way, core emulsions having the same cubic shape but different silver iodide contents were prepared. (The monodispersity of each emulsion is 1
2%) Next, using the silver halide grains obtained above as cores, the same method as above was applied (however, the potassium iodide concentration and potassium bromide concentration of solution (B) were Potassium 3.32g,
By coating the silver halide shell with potassium bromide (130Q), core/shell type silver halide emulsions having the same 14-hedral shape but different silver iodide contents were prepared.

Each of these emulsions was washed with water and desalted.

The yield of each emulsion was 8 ood.

The average grain size and silver iodide content of the core/shell type silver halide emulsion thus prepared are shown in Table 2 below.

Table 2 Next, production examples of core/shell type silver halide grains used in the present invention will be specifically explained.

(1-1) Preparation of inner core A silver iodobromide emulsion EM-1 containing 4 mol % of silver iodide was prepared using the following solution.

(Solution A-1) Ossein gelatin 39.79 Distilled water 39361β polyisopropylene-polyethyleneoxydisuccinate sodium salt 10% ethanol solution 35.4 tN magnesium sulfate 3.6 g 6% nitric acid
75.6d potassium bromide
2.06! J (Solution B-1) Ossein gelatin 35.4 g Potassium bromide 807 g Potassium iodide 47 (1 Polyisobrobylene-polyethyleneoxydisuccinate sodium salt 10% ethanol solution 3S, 4vQ Distilled water 1432112 (Solution E- 1) Silver nitrate 1200 QO1
6% nitric acid 621g distilled water
146712 (Solution F-1
) 25% KBr aqueous solution +1Ag adjustment required (solution H-1) 0.6% nitric acid pH adjustment required amount (solution 1-1) 7% sodium carbonate aqueous solution pH adjustment required amount At 40°C, JP-A-57-92523 , 57-92524
Add solution E- to solution A-1 using the mixing stirrer shown in No.
1 and 8-1 were added by simultaneous mixing method. The pAg, pH, and addition rate of solutions E-1 and B-1 during simultaneous mixing were controlled as shown in Table 3.

1) A(l) and pH were controlled by changing the flow rates of solution F-1 and solution H-1 using an 8 m variable roller tube pump.

3 minutes after the addition of solution E-1 is completed, pH is adjusted by solution 1-1.
was adjusted to 5.5.

Next, the product was desalinated and washed with water using a conventional method, and after being dispersed in an aqueous solution containing 125 g of ossein gelatin, the solution was adjusted to 48001J2 with distilled water.

According to electron microscopy, this emulsion has an average grain size of 0.09.
It was found that the emulsion was a monodisperse emulsion of μm.

Margin Table-3 Below Margin (1-2) Preparation of core/shell emulsions used in the present invention: Using the seven types of solutions shown below and using the EM-1 as a seed emulsion, three types of core/shell emulsions were prepared. An emulsion was prepared by rli.

(Solution A-2) Ossein gelatin 10g0g Distilled water 2000112 Polyisobrobylene-polyethyleneoxydisuccinate sodium salt 10% ethanol solution 6iN4-hydroxy-6-methyl-1,3,3a,7-titraazaindene 100mg28%
Ammonia water 351Q 56% acetic acid aqueous solution 451g Seed emulsion (EM-
1) 48vQ (solution B-2) Ossein gelatin 6g potassium bromide 220g potassium iodide
13.9 g4-hydroxy-6
-Methyl- 1,3,3a,7-thitraazaindene 0.6g Distilled water to 600v (solution C-2) Ossein gelatin 6g Potassium bromide 220g Potassium iodide
27.9 g4-hydroxy-6
-Methyl- 1,3,3a,7-titraazaindene 0.6g Dilute to 600d with distilled water (solution D-2) Ossein gelatin 6g Potassium bromide 260g 4-Hydroxy-
6-Methyl-1,3,3a,7-titraazaindene 0.6g Dilute to 600t12 with distilled water (Solution E-2) Silver nitrate 360g 28% aqueous ammonia 280tN Dilute to 60tN with distilled water
01Q (solution F-2) 40% KBr aqueous solution pAIII adjustment amount (solution G-2) 56% nitric acid pH 11 adjustment amount 40
Solution A- using the mixing stirrer shown above at °C.
2, by simultaneously mixing solution E-2 and solutions B-2, C-2, and D-2, the minimum time without generating new particles during the process was 63.5.
It took a few minutes to add. I)A(1・I during simultaneous mixing
) H and the addition rates of solutions E-2, B-2, C-2, and D-2 were controlled as shown in Table-4 to form Emulsion F1 and Emulsion G as shown in Table-5.

Emulsions H were prepared as shown in Table 6. l
) Ag and pH were controlled by changing the flow rates of solution F-2 and solution G-2 using a variable flow rate roller tube pump.

Two minutes after the addition of solution E-2 was completed, E was added by solution G-2.
IH was adjusted to 6.0.

Table-4 Margin below Table-5 Table-6 Next, each of these emulsions was washed with water.

The yield of each emulsion was 1500-.

According to electron microscopy, this emulsion has an average grain size of 0.3 μm.
It was a monodisperse emulsion with a coefficient of variation of layer and grain size distribution of 12%.

(1-3) Preparation of core/shell emulsions used in the present invention: Seven types of core/shell emulsions were prepared using the 12 types of solutions shown below and using the EM-1 as a seed emulsion.

(Solution A-3) Ossein gelatin 10g0g Distilled water 2000ml12 Polyisopropylene-polyethyleneoxydisuccinate sodium salt 10% ethanol solution 61J24-
Hydroxy-6-methyl-1,3,3a,7-titraazaindene 1001g28%
Ammonia water 35-i1256%
Acetic acid aqueous solution 451Q seed emulsion (E
M1) 481Q (solution B-3
) Ossein gelatin 6g Potassium bromide 220Q Potassium iodide
27.9g4-hydroxy-6-
Methyl-1,3,3a,7-thitraazaindene 0.6g Make up to 600 x fl with distilled water (Solution C-3) Ossein gelatin 6g Potassium bromide 200g Potassium iodide
41.8 g4-hydroxy-6
-Methyl- 1,3,3a,7-thitraazaindene 0.6g Dilute to 600.1 with distilled water (1m liquid D-3) Ossein gelatin 6g Potassium bromide 190g Potassium iodide
55.7174-hydroxy-6-
Methyl-1,3,3a,7-titraazaindene 0.6g Make up to 6001g with distilled water (Solution E-3) Ossein gelatin 6g Potassium bromide 1γog Potassium iodide
69.994-HumanOxy-6-methyl-1,3,3a,7-thitraazaindene 0.6g Make 6001Q with distilled water (Solution F-3) Ossein gelatin 6g Potassium bromide 240g Potassium iodide
13.994-Hydroxy-6-methyl-1,3,3a,7-titraazaindene 600 d with 0.6Q distilled water (Solution G-3) Ossein gelatin 6g Potassium bromide 230g Potassium iodide
17.4174-human Oxy-6-
Methyl-1,3,3a,7-titraazaindene o, ag Make eooll with distilled water (solution H-3) Ossein gelatin 6g Potassium bromide 250g Potassium iodide
7,0g4-,hydroxy-6-methyl-1,3,3a,7-titraazaindene 0.6g Make 600.12 with distilled water (solution ■-3) Ossein gelatin 60 Potassium bromide 260 Q4-hydroxy -6-Methyl-1,3,3a,7-thitraazaindene o,sg Distilled water to 600, Q (solution J-3) Silver nitrate 360928%
7 Nmoni7 water 280tj2 Make sooij2 with distilled water (-3 to solution) 40% KBr aqueous solution pAg adjustment required m4 solution L
-3) 56% nitric acid pH adjustment required amount At 40°C, add solution J-3 and solutions B-3, C-3, D-3, E- to the solution using the mixer shown above at 40°C. 3
, F-3, G-3, H-3, and 1-3 were added by a simultaneous mixing method over a minimum time of 63.5 minutes. DAg/EIH and solutions B-3, C-3, D- during simultaneous mixing
3. The addition rates of E-3, F-3, G-3, H-3, and I-3 were controlled as shown in Table-7, and emulsion 81 was prepared as shown in Table-8 as shown in Table-8. Add one table to the emulsion as shown.
Emulsion M1 was prepared as shown in Table 1-11. Emulsion N1 was prepared as shown in Table-12.
Emulsion 0 was prepared as shown below. The pAQ and pH were controlled using a variable flow rate roller tube pump while changing the flow rates of -3 and L-3 solutions.

Two minutes after the addition of solution J-3 was completed, p
H was adjusted to 6.0.

Margin below ゛ Table-7 Table-8 Table-9 Margin below Table-10 Margin below Table-11 Table-12 Table-13 Margin below Next, each of these emulsions was washed with water and desalted.

The yield of each emulsion was 1500 t12. Electron microscopic observation revealed that this emulsion was a monodisperse emulsion with an average grain size of 0.3 μm and a coefficient of variation in grain size distribution of 11%.

The core used in the present invention developed in this way/
The average grain size and silver iodide content of the shell type silver halide emulsion are shown in Table 14 below.

The following blank space [Preparation of organic silver salt dispersion-1] 5-methylbenzotriazole silver 28.80 obtained by reacting 5-methylbenzotriazole and silver nitrate in a water-alcohol mixed solvent and poly(N-vinylpyrrolidone) ) 16.0(l) and 4-sulfobenzotriazole sodium salt 1.33Q were dispersed in an alumina ball mill and adjusted to pH 5.5 to 20(he).

[Preparation of photosensitive silver halide dispersion] Each of the 15 types of silver halide emulsions A to 0 prepared above was mixed with the following sensitizing dye (1) and 4-hydroxy-6-methyl-1,3,3a, Fifteen kinds of photosensitive silver halide dispersions A to 0 having the following compositions were prepared by sulfur sensitization treatment with sodium thiosulfate in the presence of 7-chitrazaindene.

Silver halide (in terms of silver) 381 g Gelatin 85/2820 tffi or less Margin sensitizing dye (1) [Preparation of dye-providing substance dispersion-1] Exemplary dye-providing substance (PM-17) 35.5!3, and The following hydroquinone compound s, oog was dissolved in 200 d of ethyl acetate, and mixed with Alkanol
Mix with gelatin aqueous solution 72G containing CI, disperse with an ultrasonic homogenizer, distill off ethyl acetate, and then adjust the pH.
5.5 and it was 79 SIQ.

Hydroquinone compound H [Preparation of reducing agent solution-1] Exemplary reducing agent (R-11) 23.3 (7, below development accelerator 1.10Q, poly(N-vinylpyrrolidone) 14
．． 61J.

Dissolve the following fluorosurfactants o and sog in water and adjust the pH
5.5 and set it as 25011J2.

Development-accelerating surfactant (m, n=2, 3) [Preparation of photothermographic material-1] 12.5 m (2,
Each of the silver halide dispersions A to 0 is 6.00. ρ, 39.8i12 of dye-donor dispersion-1, and 12.5mff1 of reducing agent solution-1 were mixed, and then a hardener solvent (tetra(vinylsulfonylmethyl)methane and taurine of 1:1) was mixed.
1 (grain ratio) and dissolved in a 1% aqueous solution of phenylcarbamoylated gelatin so that the amount of tetra(vinylsulfonylmethyl)methane was 3% by weight. ) and 2.50d of polyethylene glycol 30d as a hot solvent.
After adding 3.809% of PA 0 (manufactured by Tokagaku Co., Ltd.), it was applied onto a subbed photographic polyethylene terephthalate film with a thickness of 180 μm so that the root hardness was 2.0 (J / f). Further, a protective layer made of a mixture of the phenylcarbamoylated gelatin and poly(N-vinylpyrrolidone) was provided thereon.

[Preparation of image receiving member-1] Polyvinyl chloride (n -1,1
A tetrahydrofuran solution of Wako Pure Chemical Industries, Ltd. (Wako Pure Chemical Industries, Ltd.) was applied so that the amount of polyvinyl chloride was 12 g/l'.

The photothermographic material was exposed to 1,600C, M, and S through a step wedge, and together with the image receiving member, the photothermographic material was subjected to thermal development III (developer module 2).
After heat development was carried out at 150°C for 1 minute using a 77.3M company, the photothermographic material and the image receiving member were quickly peeled off, and a magenta step wedge negative was left on the polyvinyl chloride surface of the image receiving member. The image was obtained.

The anti-copper concentration of the obtained negative image was measured using a densitometer (PDA-65, manufactured by Konishiroku Photo Industry ■), and the relative sensitivity and minimum density (
Fog) was measured. The results are shown in Table 15 below.

However, in Table 15, it is the reciprocal of the exposure amount that gives a fog over relative sensitivity of +0.3, and is a relative value with the sensitivity of sample-1 being 100.

As is clear from the results in Margin Table 15 below, silver halide containing the core/shell type silver halide grains of the present invention was Samples of heat-developable photosensitive materials using emulsions (No. 6 to 1)
It can be seen that No. 5) has good characteristics with improved photographic sensitivity and particularly marked improvement in thermal fog.

Example-2 Sample of the photothermographic material prepared in Example-1 (N 0.
1 to 15), the reciprocity law failure characteristics were investigated. The heat-developable photosensitive material was passed through a step wedge at 160°C.
Exposures of 0C, M, and S were given.

The exposure time was normally 1 second, but for the evaluation of high-intensity reciprocity law failure characteristics, the exposure time was 1/102 second and 1/10 second.
The exposure time was 4 seconds, and the exposure amount was the same as in a normal case. The high-intensity reciprocity law failure characteristic was evaluated by comparing the sensitivity in each case of normal exposure (1 second exposure), 1/102 second exposure, and 1/104 second exposure.

1/102 seconds and 1/104 for normal exposure sensitivity
The smaller the decrease in sensitivity in the case of second-second exposure, the better.

Next, heat development was performed in the same manner as in Example 1 together with the image receiving member used in Example 1 to obtain a magenta negative image. The obtained negative image was processed in the same manner as in Example-1.
Relative sensitivity was measured. The results are shown in Table 16 below.

As is clear from the results shown in Margin Table 16 below, silver halide containing the core/shell type silver halide grains of the present invention was Samples of heat-developable photosensitive materials using emulsions (No. 6 to 1)
It can be seen that in case 5), the decrease in sensitivity at exposures of 1/102 seconds and 1/104 seconds is small, and the high-illuminance reciprocity law failure characteristics are excellent.

Example 3 Silver halide emulsions A to 0 prepared in Example 1 were treated with the following sensitizing dye (2) and 4-hydroxy-6-methyl-1,
Fifteen kinds of photosensitive silver halide dispersions A' to 0' having the following compositions were prepared by sulfur sensitization treatment with sodium thiosulfate in the presence of 3,38,7-chitrazaindene.

Sensitizing dye (2) Silver halide (in terms of silver) 381 (+gelatin 85/2820 views [Preparation of dye-providing substance dispersion-2] Exemplary dye-providing substance @30.0!I+, tricresyl phosphate 30.0 (J and ethyl acetate 90.0 mj2, same as in Example-1, gelatin aqueous solution 46 (h + Add 50G-@
I named it Q.

[Preparation of heat-developable photosensitive material-2] 40% of each of the 15 types of silver halide emulsion dispersions A' to 0'. (h(1, 25.01Q of organic silver salt dispersion-1 of Example-1, 50.01g of dye-providing substance dispersion-2)
and polyethylene glycol 300 (manufactured by Kanto Kagaku Co., Ltd.) as a heat solvent. 4.20Q, 10% by weight methanol solution of 1-phenyl-4,4-dimethyl-3-pyrazolidone 1,51β, same as Example-1. Hardener 3.
OOd and 20.0112 of a 10% water-alcoholic solution of guanidine trichloroacetic acid were added onto a photographic polyethylene terephthalate film with a thickness of 180 μι which was subbed so that the amount of silver was 2.50 Q/f. It was applied to.

[Preparation of Image Receiving Member-2] The following layers were sequentially coated on a transparent polyethylene terephthalate film having a thickness of 100 μm.

(1) JR made of polyacrylic acid, (7, OOQ/f
)(2) A layer consisting of cellulose acetate. (4,0OIJ
/1') (3) A layer consisting of a 1:1 copolymer of styrene and N-benzyl to N,N-dimethyl-N-(3-maleimidopropyl)ammonium chloride and gelatin.

(Copolymer 3.0OIJ/l', gelatin 3.000
/l') The heat-developable photosensitive material-2 was exposed to 1,600 C, M, S through a step wedge;
After heating for 1 minute on a heat block at 50°C, it was attached to the image receiving member-2 soaked in water, and a 50"C150
Pressure bonding of 0 g to 800 g/cl was performed for 30 seconds, and the film was immediately peeled off. The transmission density of the yellow transparent image obtained on the surface of the image receiving member was measured using a densitometer (PDA-65, manufactured by Konishiroku Photo Industry ■), and the relative sensitivity and minimum density (fog) were measured. The results are shown in Table 17 below.

However, in Table 17, the relative sensitivity is the reciprocal of the exposure amount that gives a fog of +0.3, and is a relative value with the sensitivity of sample-1 set as 100.

As is clear from the results in Margin Table 17 below, compared to the samples (Nos. 1 to 5) using comparative silver halide emulsions, silver halide emulsions containing core/shell type silver halide grains of the present invention were used. Samples of heat-developable photosensitive materials used (No, 6 to 15
) has good characteristics with improved photographic sensitivity and particularly marked improvement in thermal fog.

Example-4 Sample of heat-developable photosensitive material prepared in Example-3 (No.
, 1 to 15) in the same manner as in Example-2,
The reciprocity law failure characteristics were investigated. The results are shown in Table 18 below.

As is clear from the results in Margin Table 18 below, silver halide containing core/shell type silver halide grains of the present invention compared to samples using comparative silver halide emulsions (N 0.1 to 15). Samples of heat-developable photosensitive materials using emulsions (No, 6~
15) It can be seen that the decrease in sensitivity at exposures of 1/102 seconds and 1/104 seconds is small, and the high-illuminance reciprocity law failure characteristics are excellent.

Patent applicant Konishiroku Photo Industry Co., Ltd. Representative Patent Attorney Ichinose Miyao g Ichi Seo 2nd Physician Stop J Riichi

Claims (1)

[Claims] The iodine content of the outermost layer of the outer shell of a core/shell type photosensitive silver halide grain consisting of an inner core and an outer shell covering the inner core is 10 mol% or less, and 1. A heat-developable photosensitive material comprising core/shell type photosensitive silver halide grains having a phase with a high iodine content in the outer shell, the iodine content of which is 6 mol% or more higher than that of the outermost layer.