JP2002287291A - Silver salt photothermographic dry imaging material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a silver salt photothermographic dry imaging material containing a small amount of silver, having high sensitivity and high maximum density, excellent in raw stock preservability as a photosensitive material and the gradation and color tone of an image area after heat development, nearly free of fogging of an unexposed area and excellent in stability of an image. SOLUTION: In the silver salt photothermographic dry imaging material obtained by forming a photosensitive layer and a non-photosensitive layer on a base by coating with a photosensitive emulsion containing organic silver salt grains, photosensitive silver halide grains and an organic solvent and a non-photosensitive composition containing a reducing agent and a binder, 78-99 mass% silver behenate based on the total amount of the organic silver salts is contained and a silver saving agent is contained in at least one of the photosensitive layer and the non-photosensitive layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a silver salt photothermographic dry imaging material.

[0002]

2. Description of the Related Art Conventionally, in the fields of medical treatment and printing plate making, waste liquids caused by wet processing of silver halide color photographic light-sensitive materials have been problematic in terms of workability. Therefore, there is a strong demand for a reduction in the amount of processing waste liquid, and there is a demand for development of a dry photographic technique that hardly generates processing waste liquid or uses no processing liquid at all.
Technology that meets these demands is a silver salt photothermographic dry imaging material that can form a high-resolution and clear black image in a space-saving, processing solution-free, and high-resolution laser imager or laser imagesetter. There is a need for the development of photographic techniques that use.

As such a silver salt photothermographic dry imaging photographic technique, for example, US Pat. No. 3,152,904
No. 3,487,075 and D.C. “Dry Silver Photographic Material (D
ry Silver Photographic Ma
terials) "(Handbook of Ima
ging Materials, Marcel Dek
ker, Inc. 48, 1991), a heat-developable silver salt photosensitive material containing an organic silver salt, a photosensitive silver halide and a reducing agent on a support is known. By using the heat-developable silver halide photosensitive material technology, a simpler and more environmentally friendly photographic system can be provided to the user without using any processing solution or processing chemical.

This heat-developable silver halide photographic material (also referred to as a silver salt photothermographic dry imaging material) uses a photosensitive silver halide particle in a photosensitive layer as an optical sensor and an organic silver salt as a supply source of silver ions. It is characterized in that an image is formed by heat development usually at 80 to 140 ° C. with a reducing agent in the photosensitive layer, and no fixing is performed. Therefore, from the viewpoint of easy supply of silver ions to silver halide and prevention of deterioration of transparency due to light scattering,
Much effort has been put into improving the organic silver particle morphology in the photosensitive layer with less effect on light scattering.

[0005] The shape and particle size of the organic silver salt particles are related to the composition of the organic acid, and it has been found that when the organic acid is made into a single composition, the organic silver salt becomes large particles and the thickness becomes large. ing. It is necessary to make small particles in order to obtain desired performances such as sensitivity, low fog density, and transparency. However, as a means for making the particles small, the particles are dispersed and / or pulverized with a high energy using a disperser or the like. There is an attempt to simply reduce the particle size by such means, but such a method causes problems such as an increase in fog, a decrease in sensitivity, and an increase in devitrification due to damage to silver halide grains and organic silver salt grains. Therefore, a method of increasing the amount of silver and adjusting the amount has been sought. However, there has been a demand for a technique capable of obtaining high sensitivity and high image density without increasing the amount of silver and reducing fog in order to reduce costs and obtain a stable image.

On the other hand, since the silver salt photothermographic dry imaging material contains an organic silver salt, silver halide particles and a reducing agent, fogging is liable to occur during the storage period before thermal development and during thermal development, and also after exposure. , Thermal development (80-250 ° C)
The non-image area (unexposed area) after the heat development processing reacts with the remaining composition to increase fog over a long period of time, and the photodegradable silver (printout Silver) easily occurs. Also, the silver image may be discolored. From such a viewpoint, a reduction in the amount of silver used has become an issue, and silver saving agents have been studied. However, preservability before development (sometimes called raw preservability) has been severely deteriorated, and it has not been possible to put it into practical use.

[0007] Silver salt photothermographic dry imaging materials include aqueous photosensitive compositions and organic solvent-based photosensitive compositions. The former is intended to increase the sensitivity and density of silver salt photothermographic dry imaging materials. At present, the performance such as gradation, color tone, and raw preservability is inferior to the latter.

Further, as described above, a silver salt photothermographic dry imaging material cannot recover silver halide in an unexposed portion with a fixing solution as in a normal silver halide photographic light-sensitive material. In addition, a large amount of silver is stored on the user side, making it difficult to recover and reuse silver resources. From such a viewpoint, development of a silver salt photothermographic dry imaging material with reduced silver is required.

[0009]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a photosensitive material having a high sensitivity and a maximum density even with a small amount of silver, a raw storage property of the photosensitive material, a gradation property of an image area after thermal development, and An object of the present invention is to provide a silver salt photothermographic dry imaging material which has excellent color tone, almost no fogging in the non-exposed area and excellent image stability.

[0010]

The present invention has the following arrangement.

(1) A photosensitive emulsion containing organic silver salt particles, photosensitive silver halide particles and an organic solvent, a photosensitive composition containing a reducing agent and a binder, and a non-photosensitive composition containing a binder, respectively. A silver salt photothermographic dry imaging material coated on a support to form a photosensitive layer and a non-photosensitive layer, containing exactly 78 to 99% by mass of silver behenate with respect to all the organic silver salts; And a silver salt photothermographic dry imaging material characterized in that at least one of the photosensitive layer and the non-photosensitive layer contains a silver saving agent.

(2) Organic silver salt particles, photosensitive silver halide particles and a photosensitive emulsion containing an organic solvent, a photosensitive composition containing a reducing agent and a binder, and a non-photosensitive composition containing a binder, respectively. A silver salt photothermographic dry imaging material coated on a support to form a photosensitive layer and a non-photosensitive layer, containing exactly 78 to 99% by mass of silver behenate with respect to all the organic silver salts; And at least one of the photosensitive layer and the non-photosensitive layer contains a silver saving agent, and is exposed to a wedge at a temperature of 123 ° C. for 1 hour.
Diffusion light in the characteristic curve of the wedge image obtained by thermal development in 3.5 seconds on the orthogonal coordinates having the same unit length of the optical density (Y axis) and the common log exposure amount (X axis) in diffused light. A silver salt photothermographic dry imaging material characterized in that the average gradation between the minimum optical density (fog density) +0.25 and the minimum optical density + 2.5 is 2.0 to 4.0.

(3) The silver salt photothermographic dry imaging material according to (1) or (2), wherein the total amount of silver per 1 m ^{2 of the} photosensitive layer is 1.0 to 1.7 g.

(4) The silver salt photothermographic dry imaging material according to any one of (1) to (3), which has two or more photosensitive layers on a support.

(5) The hue angle h _ab (JIS Z8729 standard) of an image after exposure and thermal development is 180 ° <h _ab <
The silver salt photothermographic dry imaging material according to any one of (1) to (4), which is at 270 °.

The present invention will be described in detail. The silver salt photothermographic dry imaging material of the present invention comprises, on at least one side of a transparent plastic support, organic silver salt particles (hereinafter sometimes referred to as organic silver salt) which serve as a silver supply source to a latent image nucleus during thermal development. A photosensitive emulsion formed by containing a photosensitive silver halide (hereinafter sometimes referred to as a photosensitive silver halide grain, a silver halide or a silver halide grain) and an organic solvent; Reducing agent involved in image formation, a silver compound present in non-image areas after thermal development and an antifogging agent to prevent silver from being blackened by the reducing agent, to increase the sensitivity of photosensitivity or to increase the photosensitivity wavelength One or more photosensitive compositions containing a sensitizer, a binder and an organic solvent coating solution are applied to form a photosensitive layer, and a protective layer, an intermediate layer, a back layer, and the like are provided on the photosensitive layer side or the opposite side. Non-photosensitive layer Those digits. Further, the present invention is a silver salt photothermographic dry imaging material containing at least one of a photosensitive layer and a non-photosensitive layer containing a silver-saving agent that promotes obtaining a high optical density from a low-density silver compound.

Hereinafter, the functional substance contained in the photosensitive composition will be described. [Organic silver salt] The organic silver salt that can be used in the present invention is relatively stable to light. However, in the presence of an exposed photocatalyst (such as a latent image of a photosensitive silver halide) and a reducing agent, the organic silver salt can be used. ° C ~
It is a silver source that can release silver ions when heated to 250 ° C. Examples of the organic silver salt include a silver salt of a long-chain aliphatic carboxylic acid, a silver salt of a compound containing a mercapto group or a thione group and a derivative thereof, a silver salt of a nitrogen-containing heterocyclic compound, or a ligand whose total ligand is 4.0 to 1 as stability constant
ResearchDiscl with a value of 0.0
organic (hereinafter abbreviated as RD) 17029 and 29963.

In the present invention, a long-chain aliphatic carboxylic acid is preferred as the organic acid of the organic silver salt. The long chain aliphatic carboxylic acids useful in the present invention have 10 to 3 carbon atoms.
0, for example, cellotic acid (25 carbon atoms), behenic acid (22), arachidic acid (20), stearic acid (18), palmitic acid (16), myristic acid (14), lauric acid ( 12) and the like, and an aliphatic carboxylic acid having 12 to 25 carbon atoms is preferable. Of these, particularly useful in the present invention are behenic acid, arachidic acid, stearic acid and palmitic acid.

In the present invention, the organic silver other than the long-chain aliphatic carboxylic acid includes 1- (3-carboxypropyl) thiourea, 1- (3-carboxypropyl) -3,
Carboxyalkylthioureas such as 3-dimethylthiourea; aldehydes such as reaction products of aldehydes (formaldehyde, acetaldehyde, butyraldehyde, etc.) and hydroxy-substituted acids (eg, salicylic acid, benzoic acid, 3,5-dihydroxybenzoic acid) Of a polymer reaction product of a polymer and a hydroxy-substituted aromatic carboxylic acid;
(2-carboxyethyl) -4-hydroxymethyl-4
-Thiazoline-2-thione and 3-carboxymethyl-
Thiones such as 4-thiazoline-2-thione, imidazole, pyrazole, urazole, 1,2,4-thiazole and 1H-tetrazole, 3-amino-5-benzylthio-1,2,4-triazole, and benztriazole Nitrogen-containing heterocyclic compounds such as saccharin, 5
-Chlorosalicylaldoxime, and mercaptides. The silver compounds of these organic acids are in the form of silver salts or complexes.

In the present invention, a preferred organic silver salt is a long-chain aliphatic silver carboxylate salt, which easily releases silver during thermal development and is easy to use. Among them, only one kind of aliphatic silver carboxylate, as described above, tends to increase the size of the organic silver salt particles, the thickness of the particles is so large that the supply of silver does not work well, the melting point of the organic acid is high, and the thermal development temperature is high. Are not compatible with each other, so that silver aliphatic carboxylate having a different length is mixed, whereby the supply of silver tends to be smooth. Silver behenate is the most easily used aliphatic carboxylic acid among them, but the content of other carboxylic acids is included depending on the raw material of natural products, and the content is irregular, and stable properties can be obtained. I wanted to.

In the present invention, exactly 78 to 99% by weight of silver behenate with respect to the total amount of the organic silver salt is defined as the dry organic silver salt or the silver salt photothermographic image described below. Analysis of the silver behenate in the material indicates that 78-99% by weight of silver behenate is accurately present relative to the total organic silver salt.

In the silver salt photothermographic dry imaging material of the present invention, the accurate content of silver behenate is 78 to 99% by mass, preferably 8 to the organic silver salt used.
0 to 99% by mass. The organic acid of the organic silver salt used may be a long-chain carboxylic acid alone, but may be mixed with an organic acid such as the nitrogen-containing heterocyclic compound or thio compound. It is at most 5 mass%, preferably at most 1 mass%, more preferably at most 0.1 mass%.

Normally, commercially available behenic acid is used to reduce behenic acid to 70-
It contains about 85% by mass, and further contains arachidic acid, stearic acid, palmitic acid and the like. In some cases, unsaturated carboxylic acids may be contained. Therefore, even if a silver salt of an organic acid is prepared as behenic acid, the content of behenic acid is actually smaller than the theoretical amount. In addition, since heavy metals and the like are further contained, it has been found that there is a problem in that the supply of silver during thermal development varies, the color of the image silver changes, and the storability deteriorates.

The present inventors have analyzed the purchased chemical called behenic acid in advance to determine the amount of other carboxylic acids and the contents of unnecessary substances, for example, heavy metals, unsaturated carboxylic acids, and the like. It has been found that the above-mentioned problems can be solved by using high-concentration behenic acid or high-purity behenic acid after purification. By purifying commercially available chemicals, behenic acid is purified to a high purity and has a low heavy metal content and iodine value. Unpurified behenic acid having a high concentration has a low iodine value and heavy metal content, and is suitable for the silver salt photothermographic dry imaging material of the present invention. By accurately using such behenic acid, the results of analyzing silver behenate in a silver halide particle-containing powdered organic silver salt prepared as described below or a silver salt photothermographic dry imaging material after preparation will be accurate. To 7
It was confirmed by analysis that the content was 8 to 99% by mass.
The behenic acid or organic acid used in the present invention preferably has a heavy metal content and an iodine value of 4 ppm or less and an iodine value of 1.0 or less. The purity of behenic acid is 92% by mass or more, preferably 95% by mass.
It is preferably not less than 8% by mass (arachidic acid, stearic acid or palmitic acid is not more than 8% by mass, preferably not more than 5% by mass), and the hue (APHA) is preferably not more than 100%.

In the present invention, by precisely setting the content of silver behenate to 78 to 99% by mass with respect to the total organic silver salt, the composition is stable in an atmosphere at a temperature of 55 ° C. or lower, and has a temperature around the heat development temperature (123 ° C.). Above about ℃), it becomes stable and active as a silver ion supply source, and the silver ion supply rate during thermal development becomes quick and uniform. Therefore, if an appropriate development nucleus is present, the shape of the developed silver produced is also uniform. In addition, the silver content is easily coated at a high concentration. By using such an organic silver salt using behenic acid useful in the present invention together with a silver saving agent described below, not only the sensitivity is increased, but also the maximum optical density of developed silver is significantly improved (covering power). Or, the covering power was improved), the fog density was low, and the color tone was cool, so that a preferable silver salt photothermographic dry imaging material could be obtained. Here, the covering power or covering power of the developed silver refers to the optical density per unit mass of the developed silver. Hereafter, the covering power or covering power is set to C
It may be abbreviated as P (Covering Power).

When the photosensitive layer of the silver salt photothermographic dry imaging material has a multilayer structure composed of two or more layers, at least one of the layers may contain the above-mentioned silver behenate useful in the present invention. Essentially, the other layers may contain unrefined low concentrations of silver behenate, but preferably contain silver behenate useful in the present invention. Preferably two or three layers.

To determine the amount of behenic acid, a certain amount of the purchased chemical is precisely weighed, and methanol is added thereto, followed by ultrasonic dispersion for 1 minute. The filtrate obtained by filtering it is dried, and the composition is measured by gas chromatography (GC) to find the composition of the free organic acid and the ratio to the total organic acid. As for heavy metals, organic acid samples are subjected to sulfuric acid / nitric acid decomposition treatment using a microwave-type wet decomposition apparatus, and for example, Fe, Cr or N
For i, an inductively coupled plasma emission spectrometer (I
Analyze by CP). For unsaturated carboxylic acids, J
It is evaluated by an iodine value representing the degree of unsaturation according to the method of IS K3331.

In the present invention, the produced organic silver salt is also analyzed, and the content of silver behenate is determined as follows. About 10 mg of the organic silver salt is accurately weighed, and 2
Place in a 00 ml eggplant-type Kolben. 15 ml of methanol
And 3 ml of 4 mol / l hydrochloric acid, and ultrasonically disperse for 1 minute. Add Teflon (registered trademark) zeolite and reflux for 60 minutes. After cooling, methanol 5
ml of the solution, and the substance adhering to the cooling tube is washed into an eggplant-type kolben (twice). The resulting reaction solution was extracted with ethyl acetate (100 ml of ethyl acetate and 70 ml of water were added to separate the solution,
Times). Vacuum dry for 30 minutes. 1 ml of benzanthrone solution (internal standard) is placed in a 10 ml measuring flask. Dissolve the sample in toluene, put it in a volumetric flask and make up with toluene. This is measured by GC, the mol% from the peak area of each organic acid is determined, and the composition of all organic acids can be known by determining the mass%.

Subsequently, the amount of the free organic acid which has not been converted into the organic silver salt is determined. About 20 mg of the organic silver salt sample is accurately weighed, and 10 ml of methanol is added thereto, followed by ultrasonic dispersion for 1 minute. When it is filtered and the filtrate is dried, free organic acids are extracted. Hereinafter, the composition of the free organic acid and the ratio to the total organic acid can be known by measuring with GC in the same manner as in the case of the whole organic acid. The amount obtained by subtracting the free organic acid from the total organic acid is the composition of the organic acid salt present as the organic silver salt.

In the present invention, the silver behenate is also extracted and analyzed from the produced silver salt photothermographic dry imaging material to accurately determine the content of silver behenate. Can be measured in the same procedure by peeling the photosensitive layer with a soluble organic solvent, and when there are two or more photosensitive layers, the photosensitive layer is divided into two layers and the above measurement is performed. It becomes possible by applying. The detailed method is described in Analytical Chemistry by Yutaka Okagami et al., Vol. 37, p. 41, (19.
88) can be applied.

Of course, in the present invention, the contents of arachidic acid, stearic acid, and palmitic acid obtained simultaneously are accurately determined from the quantitative results of behenic acid as a purchased drug, and the purity is known to the extent that the amount in the formulation is insufficient. Are added. As for each carboxylic acid, the one in which the purity of each carboxylic acid is quantified is used as in the case of behenic acid.

The organic silver salt can be obtained by mixing a water-soluble silver compound and an organic acid metal salt compound which forms a complex with silver.
A controlled double jet method as described in Japanese Patent No. 27643 can be preferably used. For example, an alkali metal salt (eg, sodium hydroxide, potassium hydroxide, etc.) is added to an organic acid and neutralized with nitric acid to produce an organic acid alkali metal salt soap (eg, sodium behenate, sodium arachidate, etc.). Subsequently, the metal salt soap and the aqueous solution of silver nitrate are mixed by a controlled double jet method to produce organic silver salt crystal particles. At that time, silver halide grains may be mixed.

The particle size and shape of the organic silver salt crystal particles affect the performance. The organic silver salt particles according to the present invention have an average thickness of 0.005 to 0.05 μm and an average particle size of 0.05 to 0.5 μm.
The average thickness is preferably 5 μm, particularly preferably 0.005 to 0.03 μm. Average thickness 0.00
By making it 5 to 0.05 μm, the surface area of the particles is
Silver ions can be appropriately supplied at the time of heat development, silver is appropriately supplied even in a low density portion of an image, and silver ions do not remain in a film or the like, and the image has excellent image storability. Also,
The thickness of the heat-developed silver in the high-density portion can be uniform and an image can be obtained without variation in thickness at the time of production, and the CP can be improved. When the average particle diameter is 0.05 to 0.5 μm, a silver salt photothermographic dry imaging material having no fog and excellent transparency can be obtained.

A method for obtaining the above average particle size and average thickness will be described. About the average particle size, the organic silver salt after dispersion is diluted and dispersed on a grid with a carbon support film,
A transmission electron microscope (manufactured by JEOL Ltd., 2000FX type) is used to directly take a photograph at a magnification of 5000 times, capture a negative as a digital image with a scanner, and use an image processing software to obtain a particle size of 300 or more particles on the screen. Circle equivalent diameter)
Is measured, and the average particle size is calculated.

The above average thickness is calculated by a method using a TEM (transmission electron microscope) as described below. First, the photosensitive layer applied on the support is attached to an appropriate holder with an adhesive, and the thickness is 0.1 to 0.2 μm using a diamond knife in a direction perpendicular to the support surface.
Make ultra-thin sections of m. The prepared ultrathin section is supported on a copper mesh, transferred onto a carbon film that has been hydrophilized by glow discharge, and cooled with liquid nitrogen to −130 ° C. or lower using a transmission electron microscope (hereinafter referred to as a TEM). A bright field image is observed at a magnification of 5,000 to 40,000, and the image is quickly recorded on a film, an imaging plate, a CCD camera or the like. At this time, as the visual field to be observed, it is preferable to appropriately select a portion where there is no break or looseness in the section. It is preferable to use a carbon film supported by an organic film such as ultra-thin collodion or formvar, and more preferably, it is formed on a rock salt substrate and obtained by dissolving and removing the substrate, or the organic film is formed of an organic film. This is a carbon-only film obtained by removing the solvent and ion etching. 80-400 kV as TEM acceleration voltage
Is preferable, and particularly preferably 80 to 200 kV.

For details of the electron microscope observation technique and the sample preparation technique, see "The Electron Microscopy Society of Japan, Kanto Chapter / Medical and Biological Electron Microscopy" (Maruzen), and "The Japan Electron Microscopy Society of Kanto Section / Electronics". Microscopic biological sample preparation method ”(Maruzen) can be referred to.

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

The thickness of the extracted organic silver salt particles is set to 300
Measure the number using image processing software and calculate the average value.

The method for obtaining organic silver salt particles having an average thickness of 0.005 to 0.05 μm and an average particle size of 0.05 to 0.5 μm is not particularly limited, but a method for forming an organic acid alkali metal salt soap can be used. To maintain good mixing conditions and / or mixing conditions when adding silver nitrate to the organic acid alkali metal salt soap, and to optimize the ratio of silver nitrate that reacts with the organic acid alkali metal salt soap. Is valid.

The shape of the organic silver salt particles according to the present invention is various, such as a flat plate, a bar, a needle, and a sphere, and is not particularly limited. The particles are preferred because of their large surface area and high silver supply.

In the present invention, it is not very preferable to mechanically disperse and pulverize the organic silver salt particles after they are formed, and it is not particularly preferable to produce silver halide particles during the preparation of the organic silver salt. However, when re-dispersing a dry cake having organic silver salt particles and silver halide particles,
A suitable disperser may be used. In the case of a short time, a strong one such as a high-pressure homogenizer may be used.

Examples of the disperser which can be used for pre-dispersing the cake include a media disperser, a high-pressure homogenizer, a general stirrer such as an anchor type and a propeller type, a high-speed rotary centrifugal radiation type agitator (dissolver), and a high-speed rotary shear type agitator. Machine (homomixer) can be used. Also, as the media dispersing machine, a ball mill, a planetary ball mill,
It is possible to use a rolling mill such as a vibrating ball mill, a bead mill, an attritor, and other basket mills, which are medium stirring mills.As a high-pressure homogenizer, a type that collides with a wall, a plug, or the like is divided into a plurality of types. Various types can be used, such as a type in which liquids collide with each other at high speed, and a type in which thin orifices pass through.

[Silver halide grains] The photosensitive silver halide grains of the present invention will be described below.

The silver halide grains used in the present invention may be P.I. By Glafkids; Chimie et
Physique Photographique (P
aul Montel, 1967); F. D
by uffin; Photographic Emuls
ion Chemistry (The FocalPr
ess, 1966); L. Zelikman
et al; Making and Coating
Photographic Emulsion (Th
e Focal Press, 1964) and the like, and can be prepared as a silver halide grain emulsion. That is, any of an acidic method, a neutral method, an ammonia method and the like may be used, and a method of reacting a soluble silver salt and a soluble halide salt may be any one of a one-sided mixing method, a double-sided mixing method, a combination thereof and the like. Of these, the so-called controlled double jet method of preparing silver halide grains while controlling the formation conditions is preferred. The halogen composition is not particularly limited, and may be any of silver chloride, silver chlorobromide, silver chloroiodobromide, silver bromide, silver iodobromide, and silver iodide.

In order to suppress white turbidity after image formation and obtain good image quality, the average grain size of silver halide is preferably small, and the average grain size is 0.2 μm.
Hereinafter, more preferably 0.01 to 0.17 μm, and particularly preferably 0.02 to 0.14 μm. When the silver halide grains are cubic or octahedral, so-called normal crystals, the grain size refers to the length of the edges of the silver halide grains. When the silver halide grains are tabular grains, the diameter refers to the diameter of a circular image having the same area as the projected area of the main surface.

The grain size of the silver halide grains is preferably monodispersed. The term “monodisperse” as used herein means that the coefficient of variation of the particle size determined by the following formula is 30% or less. It is preferably at most 20%, more preferably 1%.
5% or less.

Coefficient of variation of grain size (%) = (standard deviation of grain size / average of grain size) × 100 The shape of silver halide grains is cubic, octahedral, tetrahedral, tabular, spherical, etc. Grains, rod-like grains, potato-like grains and the like can be mentioned. Among them, cubic, octahedral, tetradecahedral and tabular silver halide grains are particularly preferred.

The average aspect ratio when tabular silver halide grains are used is preferably 1.5 to 100, more preferably 2 to 50. These are disclosed in U.S. Pat.
4,337, 5,314,798, 5,32
No. 0,958, etc., and the desired tabular grains can be easily obtained. Further, grains having rounded corners of silver halide grains can also be preferably used.

The crystal habit on the outer surface of the silver halide grains is not particularly limited. In the adsorption reaction of the silver sensitizing dye on the surface of the silver halide grains, a spectral sensitizing dye having crystal habit (plane) selectivity is used. When used, silver halide grains having a relatively high proportion of crystal habits adapted to the selectivity can be adsorbed, which is preferable. For example, Miller index [10
In the case of using a sensitizing dye that selectively adsorbs to the crystal plane of the silver halide grain (0), the proportion of the [100] plane in the outer surface of the silver halide grains is preferably high, and this proportion is 50%.
As described above, it is more preferably 70% or more, particularly preferably 80% or more. Incidentally, the ratio of the Miller index [100] plane is determined by the T.V. method using the adsorption dependency between the [111] plane and the [100] plane in the adsorption of the sensitizing dye. Tani, J .; Imaging
Sci. , 29, 165 (1985).

For the preparation of silver halide grains, it is preferable to use low molecular weight gelatin having an average molecular weight of 50,000 or less at the time of grain formation, and it is particularly preferable to use such gelatin at the time of nucleation of silver halide grains. The average molecular weight of the low molecular weight gelatin is preferably from 2,000 to 40,000,
5,000-25,000 is more preferable. The average molecular weight of gelatin can be measured by gel filtration chromatography.

The low-molecular-weight gelatin is generally used by enzymatically decomposing a gelatin aqueous solution having an average molecular weight of about 100,000 with a gelatin-decomposing enzyme, hydrolyzing by adding an acid or alkali to the solution, heating under atmospheric pressure or under pressure. It can be obtained by thermal decomposition by heating, decomposition by ultrasonic irradiation, or a combination of these methods.

The concentration of the dispersion medium such as gelatin at the time of nucleation is 5
% By mass or less, more preferably 0.05 to 3.0% by mass.

The silver halide grains used in the present invention are:
It is preferable to use a compound represented by the following general formula at the time of forming the particles.

YO (CH ₂ CH ₂ O) _m [CH (CH ₃ ) C
H ₂ O] _p in _{(CH 2 CH 2 O) n} Y formula, Y is a hydrogen atom, -SO ₃ M or -CO-B-C
OOM, M represents a hydrogen atom, an alkali metal atom, an ammonium group or an ammonium group substituted with an alkyl group having 5 or less carbon atoms, and B represents a linear or cyclic group forming an organic dibasic acid. . m and n are each 0 to 5
0 and p represent 1 to 100.

The polyethylene oxide compound represented by the above general formula can be prepared by adding a water-soluble halide and a water-soluble silver salt to an aqueous gelatin solution when preparing a normal silver halide photographic light-sensitive material. Process,
It has been preferably used as a defoaming agent for foams which are remarkably generated when the emulsion raw materials are stirred or moved, for example, in the step of coating the emulsion on a support. No.-9497. The polyethylene oxide compound represented by the above general formula also functions as an antifoaming agent at the time of nucleation. This compound is preferably used in an amount of 1% by mass or less based on silver, more preferably 0.0% by mass.
It is used at 1 to 0.1% by mass.

Examples of the halogen-containing compound forming silver halide include inorganic halogen compounds, onium halides, halogenated hydrocarbons, N-halogen compounds, and other halogen-containing compounds.
U.S. Pat. Nos. 4,009,039 and 3,457,075
No. 4,003,749, British Patent 1,498,9
No. 56 and JP-A-53-27027 and JP-A-53-254.
No. 20, etc., NaCl, NaBr, NaI,
Metal halides (inorganic halides) such as KCl, KBr, and KI; onium halides (such as ammonium halides) such as trimethylphenylammonium bromide, cetylethyldimethylammonium bromide, and trimethylbenzylammonium bromide; for example, iodoform, bromoform, Halogenated hydrocarbons such as carbon tetrachloride and 2-bromo-2-methylpropane; N
-Bromosuccinimide, N-bromophthalimide, N-
N-halogen compounds such as bromoacetamide;
For example, triphenylmethyl chloride, triphenylmethyl bromide, 2-bromoacetic acid, 2-bromoethanol, dichlorobenzophenone and the like can be used, and inorganic halides can be preferably used.

The silver halide used in the present invention preferably contains ions of transition metals belonging to Groups 6 to 11 of the Periodic Table of the Elements. W, Fe, Co, Ni, Cu, R
Transition metal ions such as u, Rh, Pd, Re, Os, Ir, Pt, and Au are preferable. These may be used alone or in combination of two or more of the same or different metal complexes. These metal ions may be directly introduced into the silver halide as a metal salt, but are preferably introduced into the silver halide in the form of a transition metal complex or complex ion. The content of the transition metal ion in silver halide was 1 × 10
^-9 to 1 × 10 ⁻² mol is preferable, and 1 × 10 ⁻⁸ to
1 × 10 ⁻⁴ mol is more preferred.

In the present invention, the transition metal complex or complex ion is preferably represented by the following general formula.

In the formula [ML ₆ ] ^m , M represents a transition metal selected from the elements of Groups 6 to 11 of the periodic table, and L represents a ligand, which may be the same or different. m represents 0,-, 2-, 3- or 4-. Specific examples of the ligand represented by L include halogen ion (fluoride ion, chloride ion, bromide ion, iodine ion), cyanide, cyanate, thiocyanate, selenocyanate, tellurocyanate, azide and aquo. Ligand, nitrosyl, thionitrosyl and the like, preferably aquo, nitrosyl and thionitrosyl. If an aquo ligand is present, it preferably occupies one or two of the ligands.

The following are specific examples of the transition metal coordination complex ion. 1: [RhCl _6] ^3- 2: [RuCl _6] ^3- 3: [ReCl _6] ^3- 4: [RuBr _6] ^3- 5: [OsCl _6] ^3- 6: [CrCl _6] ^4- 7: [IrCl _6] ^4- 8: [IrCl _6] ^3- 9: [Ru (NO) Cl _5] ^2- 10: [RuBr ₄ (H ₂ O)] ^2- 11: [Ru (NO) (H ₂ O ) Cl _4] ^- 12: [RhCl ₅ (H ₂ O)] ^2- 13: [Re (NO) Cl _5] ^2- 14: [Re (NO) (CN) _5] ^2- 15: [Re (NO ) Cl (CN) _4] ^2- 16: [Rh (NO) ₂ Cl _4] ^- 17: _{[Rh (NO) (H 2 O} ) Cl 4 ] ^- 18: [Ru (NO) (CN) _5] ^{2 -} 19: [Fe (CN) _6] ^3- 20: [Rh (NS) Cl _5] ^2- 21: [Os (NO) Cl _5] ^2- 22: [Cr (NO) Cl _5] ^2- 23: [Re (NO) Cl _5] ^- 24: [ _{Os (NS) Cl 4 (TeCN} ) ] ^2- 25: [Ru (NS) Cl _5] ^2- 26: _{[Re (NS) Cl 4 (SeCN} ) ] ^2- 27: [Os (NS) Cl (SCN) ₄ ] ^2-28 : [Ir (NO) Cl ₅ ] ^2- cobalt and iron compounds are preferably 6-cyano metal complexes, representative examples of which are shown below.

29: [Fe (CN) ₆ ] ^4-30 : [Fe (CN) ₆ ] ³ -31: [Co (CN) ₆ ] ^3- These transition metal ions or complex ions are converted to silver halide. It is preferably added during the formation of silver halide grains and incorporated into silver halide grains, and is added at any stage before and after preparation of silver halide grains, that is, nucleation, growth, physical ripening, and chemical sensitization. It may be added at the stage of nucleation, growth and physical ripening, but is preferably added at the stage of nucleation and growth, most preferably at the stage of nucleation. When the transition metal ion or the complex ion is added, it may be added in several divided portions, and it is preferable that the transition metal ion or the complex ion is uniformly contained in the silver halide grains. -306236, 3-167545, 4
-76534, 6-110146, 5-273
As described in JP-A No. 683, it is also preferable to incorporate the silver halide grains in a distribution.

These transition metal ion or complex ion metal compounds can be added after being dissolved in water or an appropriate organic solvent (alcohols, ethers, glycols, ketones, esters, amides, etc.). I can,
For example, an aqueous solution of the metal compound or an aqueous solution in which the metal compound and a halogen-containing compound such as NaCl and KCl are dissolved together is added to an aqueous solution of a silver salt or an aqueous solution of a halogen-containing compound during silver halide grain formation. Or a method in which a silver salt aqueous solution and a halogen-containing compound aqueous solution are added at the same time, and a silver salt aqueous solution, a halogen-containing compound aqueous solution, and a third aqueous solution of the metal compound are mixed simultaneously. A method for preparing silver halide grains, a method for charging a required amount of an aqueous solution of the metal compound into a reaction vessel during silver halide grain formation, and a method for preparing transition metal ions or There is a method in which another silver halide grain doped with a complex ion is added and dissolved. In particular,
It is preferable to add an aqueous solution of the metal compound or an aqueous solution in which the metal compound and a halogen-containing compound such as sodium chloride and potassium chloride are dissolved together to the aqueous solution of the halogen-containing compound. When adding to the surface of silver halide grains, a necessary amount of an aqueous solution of the metal compound can be introduced into the reaction vessel immediately after silver halide grains are formed, during physical ripening, or at the end or during chemical ripening.

The prepared silver halide grains can be desalted by a known desalting method such as a noodle method, flocculation method, ultrafiltration method, electrodialysis method, etc. Can be used without desalting. It is preferable that water is added to the desalted and refined silver halide grains so as to have a predetermined silver amount to form a silver halide emulsion.

In the present invention, it is preferable to arrange the silver halide grains and the reducible silver source (organic silver salt grains) in close proximity from the viewpoint of easy supply of silver. The method is to make the arrangement of the two close to each other, and once a photosensitive emulsion containing organic silver salt grains, silver halide grains and an organic solvent is prepared, and then an additive is mixed. The means for preparing the composition is not limited. A preferred method for the present invention is described in Japanese Patent Application No. 11-58.
684, as described below. First, a silver halide emulsion containing silver halide grains is prepared, and an organic acid is separately made into an organic acid soap with an alkaline solution. The silver halide emulsion is mixed with the organic acid soap. Salt particles are formed to obtain organic silver salt particles containing silver halide particles. Next, the organic silver salt particles containing silver halide particles are dried to obtain a cake-like powdered organic silver salt containing silver halide particles. In this method, a silver halide particle-containing powdered organic silver salt is dispersed in a solution in which a binder is dissolved in an organic solvent to form a photosensitive emulsion. In the photosensitive emulsion thus prepared, a state where the silver halide grains and the organic silver salt grains are very close can be obtained. Using such a photosensitive emulsion, and during the preparation of the organic silver salt particles, as described above, a high concentration of silver behenate, or a high purity, a photosensitive composition further added with a silver saving agent described below. By using the same, it is possible to obtain a silver salt photothermographic dry imaging material having high sensitivity and maximum density even with a small amount of silver, and excellent in raw storage stability and stability of the photosensitive material.

Further, as described in British Patent 1,447,454, a halogen component such as a halide ion is allowed to coexist with an organic silver salt-forming component when preparing organic silver salt particles, and silver is added thereto. By implanting ions, it is possible to produce organic silver salt grains and silver halide grains almost simultaneously. Furthermore, it is also possible to prepare a silver halide particle by converting an organic silver salt by reacting a halogen-containing compound with the organic silver salt, and to prepare a solution or dispersion of the organic silver salt in advance. Parts can be converted to photosensitive silver halide. As described above, the silver halide can also be prepared by converting a part or all of the silver in the organic silver salt to silver halide by reacting the organic silver salt with the halogen ion. Further, silver halide grains produced by converting a part of the organic silver salt to separately prepared silver halide may be used in combination.
The composition containing the organic silver salt particles and the silver halide particles prepared by the above method may be dispersed in a solution in which a binder is dissolved in an organic solvent to prepare a photosensitive emulsion.

In the present invention, the silver halide in the photosensitive composition is used in an amount of 0.001 to 0.7 with respect to 1 mol of the organic silver salt.
mol, preferably 0.03 to 0.5 mol.

[Reducing Agent] The role of the reducing agent in the silver salt photothermographic dry imaging material is as follows. In the exposed area, the organic silver salt releases silver ions by heating during thermal development.
It functions to reduce the latent image of the exposed silver halide grains as silver to form a silver image.

Examples of suitable reducing agents incorporated in the silver salt photothermographic dry imaging material of the present invention are described in US Pat.
70,448, 3,773,512, 3,59
3,863, and RD 17029 and 2996
3, and can be appropriately selected from known reducing agents. When an aliphatic silver carboxylate is used as the organic silver salt, two or more phenyl groups are substituted with an alkylene group or sulfur. Polyphenols linked by an atom, particularly an alkyl group (methyl, ethyl, propyl, t-butyl, cyclohexyl, etc.) or an acyl group (acetyl, propionyl, etc.) at at least one position adjacent to the hydroxyl substitution position of the phenyl group. Bisphenols in which two or more of the substituted phenol groups are linked by an alkylene group or sulfur, for example, the following general formula (A)
Are preferred.

[0069]

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In the formula, R represents a hydrogen atom or a group having 1 to 1 carbon atoms.
10 alkyl groups (i-propyl, butyl, 2,4,4
R ′ and R ″ are each an alkyl group having 1 to 5 carbon atoms (methyl, ethyl,
t-butyl etc.).

In addition, US Pat. No. 3,589,903,
No. 4,021,249 or British Patent 1,486
148 and JP-A-51-51933, 50
No. 36110, No. 50-116023, No. 52-8
No. 4727 or JP-B-51-35727, 2,2'-dihydroxy-1,1'-binaphthyl, 6,6'-dibromo-
Bisnaphthols described in U.S. Pat. No. 3,672,904, such as 2,2'-dihydroxy-1,1'-binaphthyl, and 4-benzenesulfonamidophenol, 2-benzenesulfonamidophenol, , 6
-Dichloro-4-benzenesulfonamidophenol,
Examples thereof include sulfonamidophenols and sulfonamidonaphthols described in U.S. Pat. No. 3,801,321 such as 4-benzenesulfonaminaphthol.

The amount of the reducing agent including the compound represented by formula (A) is preferably 1 × 10 ^{-2 to} 10 mol, particularly 1 × 10 ^{-2 to} 1.5 mol per mol of silver.
l.

The amount of the reducing agent used in the silver salt photothermographic dry imaging material of the present invention varies depending on the type of the organic silver salt, the reducing agent, and other additives.
0.05 to 10 mol per ol, preferably 0.1 to
3 mol is appropriate. Further, within the above range, two or more of the above-mentioned reducing agents may be used in combination.

In the present invention, it is preferred that the reducing agent is added and mixed with a photosensitive composition containing silver halide and organic silver salt particles and an organic solvent immediately before coating, and coating is carried out. Medium photographic performance fluctuation is small.

[Silver saving agent] The silver saving agent used in the silver salt photothermographic dry imaging material of the present invention is a compound capable of reducing the amount of silver required for obtaining a constant silver image density. . Although there are various possible mechanisms of the function of reducing the function, a compound having a function of improving the CP of developed silver is preferable.

The silver saving agent useful in the present invention includes a hydrazine derivative compound represented by the following general formula [H], a vinylene derivative compound represented by the following general formula (G), and a hydrazine derivative compound represented by the following general formula (P). The quaternary onium compound is preferably used.

[0077]

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In the general formula [H], A ₀ represents an aliphatic group, an aromatic group or a heterocyclic group which may have a substituent, or a -G ₀ -D ₀ group, and B ₀ represents a blocking. A ₁ and A ₂ each represent a hydrogen atom, or A ₁ and A _2
One of A and A _{2 represents} a hydrogen atom and the other represents an acyl group, a sulfonyl group or an oxalyl group. Here, G ₀ is -CO
Group, -COCO- group, -CS- group, -C (= NG
₁ D ₁₎ - group, -SO- group, -SO ₂ - group or -P
(O) represents a (G ₁ D ₁ ) — group, wherein G ₁ is a mere bond;
O—, —S— or —N (D ₁ ) —, wherein D ₁ represents an aliphatic group, an aromatic group, a heterocyclic group or a hydrogen atom;
When multiple D ₁ are present in a molecule, they may be the same or different. D ₀ represents a hydrogen atom, an aliphatic group, an aromatic group, a heterocyclic group, an amino group, an alkoxy group, an aryloxy group, an alkylthio group, or an arylthio group. Preferred D ₀ is a hydrogen atom, an alkyl group, an alkoxy group, or an amino group.

The aliphatic group which may have a substituent and is represented by A ₀ preferably has 1 to 30 carbon atoms, and particularly has 1 to 20 carbon atoms, such as a linear, branched or cyclic alkyl group. Groups are preferred, for example, methyl, ethyl, t-butyl, octyl, cyclohexyl, benzyl and the like. These are further suitable substituents, for example, aryl, alkoxy, aryloxy, alkylthio, arylthio. , A sulfoxy group, a sulfonamide group, a sulfamoyl group, an acylamino group, a ureido group and the like.

The aromatic group represented by A ₀ is preferably a monocyclic or condensed ring aryl group. For example, a benzene ring or a naphthalene ring, and the heterocyclic group represented by A ₀ is a monocyclic or condensed ring. In nitrogen, sulfur, a heterocyclic group containing at least one hetero atom selected from oxygen atoms is preferable,
For example, pyrrolidine, imidazole, tetrahydrofuran, morpholine, pyridine, pyrimidine, quinoline,
Examples include groups such as thiazole, benzothiazole, thiophene, and furan rings. Aromatic groups A _0, heterocyclic group or -G ₀ -D ₀ group may have a substituent.

A ₀ is particularly preferably an aryl group or a -G ₀ -D ₀ group, and A ₀ preferably contains at least one diffusion-resistant group or a silver halide adsorbing group promoting group. As the diffusion-resistant group, a ballast group commonly used in immobile photographic additives such as couplers is preferable. As the ballast group, a photographically inert alkyl group, alkenyl group, alkynyl group, alkoxy group, phenyl group ,
Examples thereof include a phenoxy group and an alkylphenoxy group, and the total number of carbon atoms in the substituent is preferably 8 or more. Examples of the silver halide adsorption accelerating group include thiourea, thiourethane, mercapto, thioether, thione, heterocyclic, thioamide heterocyclic, mercapto heterocyclic, and those described in JP-A-64-90439. Adsorbing groups and the like can be mentioned.

[0082] B ₀ represents a blocking group, preferably a -G ₀ -D ₀ group, G ₀ has the same definition as G ₀ of A _0, A preferred G ₀ -CO- group, -COCO- group It is. D _0, G ₁ is and D ₁ have the same meanings as those of A _0, preferably D ₀ also is similar to that of A _0.

A ₁ and A ₂ both represent a hydrogen atom, or _one of A ₁ and A ₂ is a hydrogen atom and the other is an acyl group such as an acetyl group, a trifluoroacetyl group, a benzoyl group, a methanesulfonyl group, a toluene group. It represents a sulfonyl group such as a sulfonyl group or an oxalyl group such as an ethoxalyl group.

Preferred hydrazine derivatives represented by the general formula [H] further include the following general formulas (H-1) and (H-
2), (H-3) and (H-4).

[0085]

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In the general formula (H-1), R ₁₁ , R ₁₂ and R ₁₃ each represent a substituted or unsubstituted aryl group or a heteroaryl group. Methylphenyl, naphthyl and the like can be mentioned. Specifically as a heteroaryl group,
Examples include groups such as triazole, imidazole, pyridine, furan, and thiophene. R ₁₁ and R ₁₂
And R ₁₃ may each be linked via any linking group. When R ₁₁ , R ₁₂ and R ₁₃ have a substituent, the substituent may be an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a heterocyclic group, a heterocyclic group containing a quaternized nitrogen atom, A hydroxyl group, an alkoxy group (including a group repeatedly containing an ethyleneoxy group or a propyleneoxy group unit), an aryloxy group, an acyloxy group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a carbamoyl group, a urethane group, a carboxyl group, Imide group, amino group, carbonamide group, sulfonamide group, ureido group, thioureido group, sulfamoylamino group, semicarbazide group, thiosemicarbazide group, hydrazino group, quaternary ammonium group, alkyl,
Aryl or heterocyclic thio group, mercapto group, alkyl or arylsulfonyl group, alkyl or arylsulfinyl group, sulfo group, sulfamoyl group, acylsulfamoyl group, alkyl or arylsulfonylureido group, alkyl or arylsulfonylcarbamoyl group, halogen atom , A cyano group, a nitro group, a phosphoramide group and the like. Preferably, all of R ₁₁ , R ₁₂ and R ₁₃ are substituted or unsubstituted phenyl groups, and more preferably, all of R ₁₁ , R ₁₂ and R ₁₃ are unsubstituted phenyl groups.

R ₁₄ represents a heteroaryloxy group or a heteroarylthio group. Specific examples of the heteroaryloxy group include pyridyloxy, pyrimidyloxy, indolyloxy, benzothiazolyloxy, benzimidazolyloxy, furyloxy, Examples include thienyloxy, pyrazolyloxy, imidazolyloxy and the like. Specific examples of the heteroarylthio group include pyridylthio, pyrimidylthio, indolylthio,
Examples include benzothiazolylthio, benzimidazolylthio, furylthio, thienylthio, pyrazolylthio, imidazolylthio, and the like. R ₁₄ is preferably a pyridyloxy group or a thienyloxy group.

[0088] A ₁ and A ₂ have the same meanings as A ₁ and A ₂ in the general formula (H), preferably A ₁ and A ₂ are both hydrogen atoms.

In the general formula (H-2), R ₂₁ represents a substituted or unsubstituted alkyl group, aryl group or heteroaryl group. Specific examples of the alkyl group include methyl, ethyl, t-butyl, 2-octyl, cyclohexyl, benzyl, and diphenylmethyl groups. Specific examples of the aryl group and the heteroaryl group include those represented by the general formula (H -1) of R _11, R ₁₂ and R ₁₃ and may be exemplified the same. When R ₂₁ has a substituent, specific examples of the substituent include R ₁₁ , R ₁₂ and R _12.
The same substituents as in the case of ₁₃ can be mentioned. R ₂₁ is preferably an aryl group or a heteroaryl group, and particularly preferably a substituted or unsubstituted phenyl group.

R ₂₂ represents hydrogen, an alkylamino group, an arylamino group, or a heteroarylamino group. Specific examples of the alkylamino group include methylamino, ethylamino, propylamino, butylamino, dimethylamino,
Examples thereof include diethylamino and ethylmethylamino. Examples of the arylamino group include an anilino group and the like, and examples of the heteroaryl group include a thiazolylamino, benzimidazolylamino, and a benzothiazolylamino group. As R ₂₂ is dimethylamino group or diethylamino group is preferable.

[0091] A ₁ and A ₂ have the same meanings as A ₁ and A ₂ as described in the general formula (H-1). In the general formula (H-3),
R ₃₁ and R ₃₂ each represent a monovalent substituent, and examples of the monovalent substituent include R ₁₁ , R ₁₂ and R described in Formula (H-1).
The groups exemplified as the substituent of ₁₃ can be mentioned, and preferred are an alkyl group, an aryl group, a heteroaryl group, an alkoxy group and an amino group. More preferably, it is an aryl group or an alkoxy group. Particularly preferred are those in which at least one of R ₃₁ and R ₃₂ is a t-butoxy group, and another preferred structure is that when R ₃₁ is a phenyl group, R ₃₂ is a t-butoxy group.

G ₃₁ and G ₃₂ represent a —CO— group, —COCO—
Group, -CS- group, -SO- group, -SO ₂ - group, -P
(O) R ₃₃ - represents a group or an iminomethylene group, R ₃₃ represents an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an alkoxy group, an alkenyloxy group, alkynyloxy group, an aryloxy group, an amino group. Where G
_{When 31} is a sulfonyl group, G ₃₂ is not a carbonyl group.
G ₃₁ and G ₃₂ are preferably a —CO— group, —COC
An O- group, a sulfonyl group or a -CS- group, more preferably a -CO- group or a sulfonyl group. A ₁ and A ₂ have the same meanings as A ₁ and A ₂ described in formula (H-1).

In formula (H-4), R ₄₁ , R ₄₂ and R ₄₃ are the same as R ₁₁ , R ₁₂ and R in formula (H-1).
Synonymous with ₁₃ . Each of R ₄₁ , R ₄₂ and R ₄₃ is preferably a substituted or unsubstituted phenyl group,
More preferably, each of R ₄₁ , R ₄₂ and R ₄₃ is an unsubstituted phenyl group. Although R ₄₄ and R ₄₅ is an unsubstituted or substituted alkyl group, specific examples of methyl, ethyl, t- butyl, 2-octyl, cyclohexyl, benzyl, it can be mentioned groups such as diphenylmethyl.
R ₄₄ and R ₄₅ are preferably each an ethyl group. A
₁ and A ₂ have the same meanings as A ₁ and A ₂ described in formula (H-1).

The compounds represented by formulas (H-1) to (H-4) can be easily synthesized by known methods. For example, it can be synthesized with reference to U.S. Patent Nos. 5,464,738 and 5,496,695.

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

In the vinylene derivative compound represented by the general formula (G), X and R are represented in the form of cis, but the form in which X and R are trans is also included in the general formula (G). This is the same in the structural representation of a specific compound.

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

R represents a halogen atom, a hydroxyl group, an alkoxy group, an aryloxy group, a heterocyclic oxy group, an alkenyloxy group, an acyloxy group, an alkoxycarbonyloxy group, an aminocarbonyloxy group, a mercapto group, an alkylthio group, an arylthio group, Ring thio group,
Alkenylthio, acylthio, alkoxycarbonylthio, aminocarbonylthio, organic or inorganic salts of hydroxyl or mercapto (sodium, potassium, silver, etc.), amino, alkylamino, cyclic amino (Such as pyrrolidino), an acylamino group,
It represents an oxycarbonylamino group, a heterocyclic group (such as a 5- to 6-membered nitrogen-containing heterocyclic group, benzotriazolyl, imidazolyl, triazolyl, or tetrazolyl group), a ureido group, or a sulfonamide group. X and W, and X and R may be bonded to each other to form a cyclic structure. Examples of the ring formed by X and W include pyrazolone, pyrazolidinone, cyclopentanedione, β-ketolactone, β-ketolactam ring and the like.

The general formula (G) will be further described.
The electron-withdrawing group represented by is a substituent whose substituent constant σp can take a positive value. Specifically, substituted alkyl groups, halogen-substituted alkyl groups, substituted alkenyl groups, substituted / unsubstituted alkynyl groups, substituted aryl groups, substituted / unsubstituted heterocyclic groups, halogen atoms, cyano groups, acyl groups, thioacetyl groups , Oxalyl group, oxyoxalyl group, thiooxalyl group, oxamoyl group, oxycarbonyl group, carboxyl group, thiocarbonyl group, carbamoyl group, thiocarbamoyl group, sulfonyl group, sulfinyl group, oxysulfonyl group, thiosulfonyl group, sulfamoyl group, Oxysulfinyl group, thiosulfinyl group, sulfinamoyl group, phosphoryl group, nitro group, imino group, N-carbonylimino group, N-sulfonylimino group, dicyanethylene group, ammonium group, sulfonium group, phosphonium group, pyrylium group, immonium Can be mentioned beam group, an ammonium group, a sulfonium group, a phosphonium group, an immonium group also include those heterocyclic forming a ring. 0.30 as σp value
The above substituents are particularly preferred.

Examples of the alkyl group represented by W include methyl, ethyl, trifluoromethyl and the like, examples of the alkenyl group include vinyl, halogen-substituted vinyl and cyanovinyl, and examples of the alkynyl group include acetylenyl and cyanoacetylenyl. Examples of the aryl group include nitrophenyl, cyanophenyl, and pentafluorophenyl, and examples of the heterocyclic group include pyridyl, pyrimidyl, triazinyl, succinimide, tetrazolyl, triazolyl, imidazolyl, and benzoxazolyl. W is preferably an electron-withdrawing group having a positive σp value, and more preferably having a value of 0.30 or more.

R is preferably a hydroxyl group, a mercapto group, an alkoxy group, an alkylthio group, a halogen atom, an organic or inorganic salt of a hydroxyl group or a mercapto group, or a heterocyclic group, and more preferably a hydroxyl group. And an organic or inorganic salt of an alkoxy group, a hydroxyl group or a mercapto group, and a heterocyclic group. Particularly preferred are an organic or inorganic salt of a hydroxyl group, a hydroxyl group or a mercapto group.

In the general formula (P), Q represents a nitrogen atom or a phosphorus atom, X ⁻ represents an anion, and R ₁ , R ₂ , R ₃
And R ₄ each represent a hydrogen atom or an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a heterocyclic group, an amino group and the like. Incidentally, R _{1 to} R ₄ may be connected to each other to form a ring. The ring which R ₁ , R ₂ , R ₃ and R ₄ can form by connecting to each other includes piperidine, morpholine, piperazine, quinuclidine, pyridine, pyrrole,
Examples include imidazole, triazole, and tetrazole rings. The groups represented by R ₁ , R ₂ , R ₃ and R ₄ may have a substituent such as a hydroxyl group, an alkoxy group, an aryloxy group, a carboxyl group, a sulfo group, an alkyl group and an aryl group. As R ₁ , R ₂ , R ₃ and R ₄ , a hydrogen atom and an alkyl group are preferred.

[0103] X ^- include anions represented by the halogen ion, sulfate ion, nitrate ion, acetate ion, may be mentioned inorganic and organic anions, such as p- toluenesulfonic acid ion.

More preferably, the following general formula (Pa):
A compound represented by (Pb) or (Pc); and a compound represented by the following general formula [T].

[0105]

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Formula (Pa), (Pb) or (Pc)
In the above, A ¹ , A ² , A ³ , A ⁴ and A ⁵ represent a group of nonmetallic atoms for completing a nitrogen-containing heterocyclic ring, and include an oxygen atom,
It may contain a nitrogen atom or a sulfur atom, and the benzene ring may be condensed. The heterocyclic ring composed of A ¹ , A ² , A ³ , A ⁴ and A ⁵ may have a substituent and may be the same or different. As the substituent, an alkyl group, an aryl group, an aralkyl group, an alkenyl group, an alkynyl group,
Halogen atom, acyl group, alkoxycarbonyl group, aryloxycarbonyl group, sulfo group, carboxyl group, hydroxyl group, alkoxy group, aryloxy group, amide group, sulfamoyl group, carbamoyl group, ureido group, amino group, sulfonamide group, It represents a sulfonyl group, a cyano group, a nitro group, a mercapto group, an alkylthio group, or an arylthio group.

Preferred examples of A ¹ , A ² , A ³ , A ⁴ and A ⁵ include a 5- or 6-membered ring (pyridine, imidazole,
Rings such as thiozole, oxazole, pyrazine and pyrimidine), and a more preferred example is a pyridine ring.

Bp represents a divalent linking group, and m represents 0 or 1. Examples of the divalent linking group include an alkylene group, an arylene group, an alkenylene _{group, -SO 2 -, - SO -} , -
O -, - S -, - CO -, - N (R 6) - a representative of those composed solely or in combination. Here, R ⁶ represents an alkyl group, an aryl group, or a hydrogen atom. Preferred examples of Bp include an alkylene group and an alkenylene group.

R ¹ , R ² and R ⁵ each have 1 to 20 carbon atoms
Represents an alkyl group. Further, R ¹ and R ² may be the same or different. The alkyl group represents a substituted or unsubstituted alkyl group, and examples of the substituent include A ¹ , A ² , A ³ ,
The substituents are the same as those described as the substituents for A ⁴ and A ⁵ .

Preferred examples of R ¹ , R ² and R ⁵ include:
Each is an alkyl group having 4 to 10 carbon atoms. More preferred examples include a substituted or unsubstituted aryl-substituted alkyl group.

[0111] Xp ^- is a counter ion necessary to balance the charge of the whole molecule, expressed as chlorine ion, bromine ion, iodine ion, nitrate ion, sulfate ion, p- toluenesulfonate, the oxalato or the like. np represents the number of counter ions required to balance the charge of the entire molecule,
Np is 0 in the case of an intramolecular salt.

The substituents R ₅ , R ₆ and R ₇ of the phenyl group of the triphenyltetrazolium compound represented by the general formula [T]
Is preferably a hydrogen atom or an electron-withdrawing group having a negative σp.

The Hammett's sigma value for the phenyl group is described in many literatures, for example, the Journal of Medical Chemistry.
Chemistry) 20, vol. 304, p. This can be seen in reports such as C. Hansch. Preferred groups having a negative sigma value include methyl, ethyl, cyclopropyl, propyl, i-propyl, cyclobutyl, butyl, i
-Butyl group, pentyl group, cyclohexyl group, amino group, acetylamino group, hydroxyl group, methoxy group,
Examples thereof include an ethoxy group, a propoxy group, a butoxy group, and a pentoxy group, all of which are useful as substituents of the compound of the general formula [T].

N represents 1 or 2, and examples of the anion represented by X _T ^n- include halogen ions such as chloride ion, bromide ion and iodide ion; and inorganic acids such as nitric acid, sulfuric acid and perchloric acid. Acid radicals of organic acids such as sulfonic acid and carboxylic acid; anionic activators, specifically higher alkylbenzenes such as lower alkylbenzenesulfonic acid anions such as p-toluenesulfonic acid anions and p-dodecylbenzenesulfonic acid anions Sulfonate anion,
Higher alkyl sulfate anions such as lauryl sulfate anion, borate-based anions such as tetraphenylboron, dialkyl sulfosuccinate anions such as di-2-ethylhexyl sulfosuccinate anion, higher fatty acid anions such as cetyl polyethenoxy sulfate anion, Polymers such as polyacrylic acid anions and the like having an acid radical attached thereto can be mentioned.

The quaternary onium compound can be easily synthesized according to a known method.
chemical Reviews vol. 55, 33
The method described on pages 5-483 can be referred to.

The amount of the silver saving agent added is 1 mol of organic silver salt.
10 ^{-5 to 1} mol, preferably 10 ^{-4 to} 5 × 1 to 1
It is in the range of 0 ^-1 mol.

[Anti-fogging agent] The biggest difference in the structure of the silver salt photothermographic dry imaging material as compared with the ordinary silver halide silver halide photographic light-sensitive material is that the latter light-sensitive material has no fog or Photosensitive silver halide, silver carboxylate, and a reducing agent which may cause the generation of printout silver (printed-out silver) are contained and are contained in a large amount. In addition, since desilvering by the fixer is not performed,
They remain in the non-image part. Such a silver salt photothermographic dry imaging material requires a technology for preventing fog and stabilizing the image, which is effective for maintaining storage stability not only before development but also after development.

The antifoggant used in the silver salt photothermographic dry imaging material of the present invention will be described.

As described above, reducing agents useful in the present invention mainly have protons such as bisphenols and sulfonamidophenols.
The compound is preferably a compound capable of inactivating the reducing agent by generating active species capable of extracting hydrogen of the reducing agent and preventing silver ions of the organic silver salt from being reduced to silver. In addition, this compound is a colorless photo-oxidizable substance that cannot reduce the silver ions released from the organic silver salt during thermal development in the non-image exposure area, and generates free radicals when exposed to light. A compound which is generated and becomes a reactive species so that silver ions cannot be reduced is preferable.

Accordingly, the antifoggant may be any compound as long as it has such a function, but is preferably an organic free radical comprising a plurality of atoms. As a compound generating these free radicals, the generated free radicals react with a reducing agent,
Those having a carbocyclic or heterocyclic aromatic group having a size and structure capable of providing stability sufficient for contacting for a sufficient time to inactivate the reducing agent are preferable. It is preferable that at least two of these compounds are contained in the constituent layer on the photosensitive layer side.

The following general formulas [1] to [4] can be mentioned as preferred compounds in the present invention as antifoggants.

[0122]

Embedded image

In the formula of the biimidazolyl compound of the general formula [1] of the antifoggant according to the present invention, R ₁ , R ₂ and R
₃ (which may be the same or different) is an alkyl group, alkenyl group, alkoxy group, aryl group, hydroxyl group, halogen atom, aryloxy group, alkylthio group, arylthio group, acyl group, sulfonyl group, acylamino group, sulfonyl It represents an amino group, an acyloxy group, a carboxyl group, a cyano group, a sulfo group or an amino group. Among these, an aryl group, an alkenyl group and a cyano group are more preferred.

The above biimidazolyl compounds are disclosed in US Pat. No. 3,734,733 and British Patent 1,271,177.
Can be produced by the production method described in the specification and a method analogous thereto.

Examples of the antifoggant useful in the present invention include an iodonium compound represented by the above general formula [2], wherein Q includes an atom necessary for completing a 5- to 7-membered ring. And the necessary atom is a carbon atom,
It is selected from a nitrogen atom, an oxygen atom and a sulfur atom. R ^1, R ² and R ³ R ₁ of formula (1), R ₂ and R ₃
And among these, an aryl group, an alkenyl group and a cyano group are more preferred. Any of R ¹ , R ² and R ³ may be bonded to each other to form a ring. R ⁴ represents a carboxylate group such as acetate, benzoate, trifluoroacetate and O ⁻ .
W represents 0 or 1. X ^- is an anionic counterion, as suitable _{^{examples, CH 3 COO -, CH 3}} SO 3 - and PF ₆ ^- is. When R ³ is a sulfo group or a carboxyl group, W is 0 and R ⁴ is O ⁻ .

Among the iodonium compounds of the general formula [2], particularly preferred compounds are represented by the general formula [3]. In the formula, R ¹ , R ² , R ³ , R ⁴ , X ⁻ and W each have the same meaning as in the above general formula [2], and Y is —CH ＝ (in this case,
A benzene ring) or -N = (in this case, a pyridine ring).

The above iodonium compounds are described in Org. Sy
n. , 1961 and Fieser; Advanced
Organic Chemistry (Reinho
ld, N.M. Y. , 1961) and a method analogous thereto.

The compound of the general formula [4] is an active halogen
It is a compound that produces a hydrogen atom (halogen radical).
In the general formula [4], Q represents an aryl group or a heterocyclic group
Represents X₁, X_TwoAnd X_ThreeRepresents a hydrogen atom and a halogen, respectively.
Atom, acyl group, alkoxycarbonyl group, arylo
Represents a carbonyl group, a sulfonyl group or an aryl group.
However, at least one is a halogen atom. Y is -C
O-, -SO- or -SO_TwoRepresents-. Represented by Q
The aryl group may be monocyclic or condensed, and is preferably
Or a monocyclic or bicyclic phenyl group having 6 to 30 carbon atoms,
An aryl group such as a phenyl group, and more preferably a phenyl group.
And a naphthyl group, more preferably a phenyl group.
is there. The heterocyclic group represented by Q has a small number of N, O or S
3-10 membered saturated or unsaturated containing at least one atom
And these are monocyclic or fused with other rings
A ring may be formed. As a heterocyclic group, preferably a condensed
A 5- or 6-membered unsaturated heterocyclic group which may have a ring
And more preferably a 5- or 6-membered member which may have a condensed ring.
Is an aromatic heterocyclic group. More preferably, it contains a nitrogen atom.
5- or 6-membered aromatic heterocyclic group optionally having a condensed ring
And particularly preferably a condensation containing 1 to 4 nitrogen atoms.
A 5- or 6-membered aromatic heterocyclic group which may have a ring,
You. Preferred as a heterocyclic ring in such a heterocyclic group
Means imidazole, pyrazole, pyridine, pyrimid
, Pyrazine, pyridazine, triazole, triazine
, Indole, indazole, pudding, thiadiazo
, Oxadiazole, quinoline, phthalazine, naphthy
Lysine, quinoxaline, quinazoline, cinnoline, pute
Lysine, acridine, phenanthroline, phenazine,
Tetrazole, thiazole, oxazole, benzimi
Dazole, benzoxazole, benzothiazole, a
It is a ring of dorenin, tetrazaindene, etc.
Or imidazole, pyridine, pyrimidine, pyrazine
, Pyridazine, triazole, triazine, thiadia
Sol, oxadiazole, quinoline, phthalazine, na
Futhyridine, quinoxaline, quinazoline, cinnoline,
Tetrazole, thiazole, oxazole, benzimi
Dazole, benzoxazole, benzothiazole, te
A ring such as tolazaindene, more preferably imidazo
, Pyridine, pyrimidine, pyrazine, pyridazine,
Triazole, triazine, thiadiazole, quinori
, Phthalazine, naphthyridine, quinoxaline, quinazo
Phosphorus, cinnoline, tetrazole, thiazole, benzo
It is a ring such as imidazole and benzothiazole, and is particularly preferable.
Preferably, a pyridine ring, a thiadiazole ring, a quinoline ring,
It is a benzothiazole ring. An aryl group represented by Q
And a heterocyclic group are represented by -YC (X ₁) (X_Two) (X_Three)Others
It may have a substituent.
A kill group, an alkenyl group, an aryl group, an alkoxy group,
Reeloxy group, acyloxy group, acyl group, alkoxy
Cycarbonyl group, aryloxycarbonyl group, acyl
Oxy group, acylamino group, alkoxycarbonylamido
Group, aryloxycarbonylamino group, sulfonyl
Amino group, sulfamoyl group, carbamoyl group, sulfo
Nil group, ureido group, phosphoramide group, halogen atom,
Ano group, sulfo group, carboxyl group, nitro group, heterocycle
Group, more preferably an alkyl group, an aryl group,
Lucoxy group, aryloxy group, acyl group, acylamido
Group, alkoxycarbonylamino group, aryloxy
Carbonylamino group, sulfonylamino group, sulfamo
Yl group, carbamoyl group, ureido group, phosphoramide group,
Halogen atom, cyano group, nitro group, heterocyclic group,
More preferably, alkyl group, aryl group, alkoxy
Group, aryloxy group, acyl group, acylamino group,
Rufonylamino group, sulfamoyl group, carbamoyl
Group, halogen atom, cyano group, nitro group or heterocyclic group.
And particularly preferably an alkyl group, an aryl group, and a halogen.
Is an atom. X₁, X_TwoAnd X_ThreeIs preferably halogen
Atom, haloalkyl group, acyl group, alkoxycarbonyl
Group, aryloxycarbonyl group, carbamoyl group,
A sulfamoyl group, a sulfonyl group, and a heterocyclic group.
More preferably, a halogen atom, a haloalkyl group, an acyl
Group, alkoxycarbonyl group, aryloxy carbonyl
And a sulfonyl group, more preferably a halogen atom.
And a trihalomethyl group, particularly preferably halogen
Is an atom. Of the halogen atoms, preferably chlorine,
Bromine and iodine atoms, more preferably chlorine and bromine atoms
And particularly preferably a bromine atom. Y is -CO
-, -SO-, -SO_Two-, Preferably -SO_Two−
It is.

In the present invention, the above-mentioned general formulas [1] to
It is preferable to contain two or more selected from all the compounds of [4]. Further, by using the silver saving agent of the present invention in combination with two or more kinds selected from all of the compounds represented by the general formulas [1] to [4], a silver salt photothermographic dry imaging material having a more preferable color tone can be obtained. It has become possible.

The addition amount of the compound represented by the general formula [4] is preferably within a range that does not substantially cause an increase in printout silver due to the formation of silver halide. It is preferably at most 150%, more preferably at most 100%, by mass, based on the compound of [3].

In the present invention, the amount of the compounds represented by the general formulas [1] to [4] is 0.001 to 0.1 mol /
m ² , preferably in the range of 0.005 to 0.05 mol / m ² . The compound can be contained in any constituent layer of the silver salt photothermographic dry imaging material, but is preferably contained in the vicinity of the reducing agent.

In the present invention, as the compound which inactivates the reducing agent and prevents the reducing agent from reducing the organic silver salt to silver, it is preferable that the reactive species is not a halogen atom. Compounds that release active species other than halogen atoms used in the present invention can also be used in combination with the compounds that release active species that are not halogen atoms.

Many compounds capable of releasing this halogen atom as an active species are known, and good effects can be obtained by using them in combination.

In addition to the above-mentioned compounds, the silver salt photothermographic dry imaging material of the present invention may contain a compound conventionally known as an antifoggant. The compound may be a compound capable of generating seeds or a compound having a different antifogging mechanism. For example, U.S. Pat. Nos. 3,589,903, 4,546,075, 4,452,885, 3,874,946, 4,756,999, and No. 59-57234, 9-288328
And compounds described in JP-A-9-90550. Further, other antifoggants are disclosed in U.S. Pat. No. 5,028,523 and European Patent No. 60.
No. 0,587, No. 605,981, No. 631,1
No. 76 can be mentioned.

The antifoggant according to the present invention, in particular,
A compound that generates a reactive species capable of oxidizing silver by exposure to ultraviolet light or visible light, and a reaction that can inactivate the reducing agent and prevent silver ions of the organic silver salt from being reduced to silver. The compound that generates the active species inactivates silver ions released from the organic silver salt particles after thermal development of the unexposed portion of the silver salt photothermographic dry imaging material of the present invention, so that the fog density on a white background is extremely low. It can be made smaller, which is preferable. Particularly, in combination with the high-purity silver behenate according to the present invention, fog concentration, raw storage stability,
It was found that the image stability was excellent.

[Sensitizer] <Chemical sensitizer> The intrinsic sensitivity can be improved by chemically sensitizing the silver halide grains of the silver salt photothermographic dry imaging material. As a method of chemical sensitization, for example, Japanese Patent Application Nos. 2000-57004 and 2000-570
A chemical sensitizing center (chemical sensitizing nucleus) is formed by utilizing a compound that releases a chalcogen such as sulfur, selenium, and tellurium or a noble metal compound that releases a noble metal ion such as a gold ion by the method disclosed in US Pat. Can be formed. In the present invention, chemical sensitization with the following organic sensitizer containing a chalcogen atom is preferable. The organic sensitizer containing a chalcogen atom is preferably a compound having a group capable of adsorbing to silver halide and a site of an unstable chalcogen atom. Examples of these organic sensitizers include JP-A-60-150046 and JP-A-4-1092.
Nos. 40 and 11-218874, which have a structure in which a chalcogen atom is bonded to a carbon atom or a phosphorus atom by a double bond. Preferably, it is a compound. The amount of the organic sensitizer chalcogen compound to be used, silver halide grains will vary due reaction environment when subjected to chemical sensitization of silver halide 1mol per 10 ^-8
It is preferably 10 ⁻² mol, more preferably 10 ⁻⁷ to 1 mol.
0 ^-3 mol. The chemical sensitizing environment in the present invention is not particularly limited, but is preferably in the presence of a compound capable of extinguishing or reducing the size of chalcogenide or silver nuclei on the photosensitive silver halide grains, and particularly, in the presence of silver. It is preferable to carry out chemical sensitization with an organic sensitizer containing a chalcogen atom in the presence of an oxidizing agent capable of oxidizing the nucleus. As a condition of the chemical sensitization, a preferable pAg is 6 to 11, more preferably 7 to 11. And preferably 10 to 10, more preferably 5 to 8, and the temperature is preferably 30 ° C or lower.

The chemical sensitization using an organic sensitizer is also preferably carried out in the presence of a spectral sensitizing dye described later or a heteroatom-containing compound having an adsorptivity to silver halide grains. By performing such chemical sensitization, dispersion of the central core of the chemical sensitization can be prevented, and silver halide grains having high sensitivity and low fog density can be obtained. As the hetero atom-containing compound having an adsorptivity to silver halide grains, a nitrogen-containing heterocyclic compound described in JP-A-3-24537 can be mentioned as a preferred example. Examples of useful heterocycles of the nitrogen-containing heterocyclic compound include pyrazole, pyrimidine, 1,2,4-triazole,
2,3-triazole, 1,3,4-thiadiazole,
1,2,3-thiadiazole, 1,2,4-thiadiazole, 1,2,5-thiadiazole, 1,2,3,4-
Each ring such as tetrazole, pyridazine, 1,2,3-triazine, and a ring in which two or three of these rings are condensed, for example, rings such as triazolotriazole, diazaindene, triazaindene, and pentaazaindene. . Also useful are condensed heterocycles of a monocyclic heterocycle and an aromatic ring, such as phthalazine, benzimidazole, indazole, benzothiazole and the like. Among these, an azaindene ring is more preferable, and a hydroxyl group is preferable as a substituent, and hydroxytriazaindene, tetrahydroxyazaindene, and hydroxypentazaindene are more preferable. The heterocyclic ring may have a substituent other than a hydroxyl group, for example, an alkyl group, a substituted alkyl group, an alkylthio group, an amino group, a hydroxyamino group, an alkylamino group, a dialkylamino group, an arylamino group, a carboxyl group, It may have an alkoxycarbonyl group, a halogen atom, a cyano group and the like. The addition amount of these heterocyclic compounds varies over a wide range depending on the size, composition, and other conditions of the silver halide grains, but the approximate amount is 10 ^-6 to 1 mol per mol of silver halide.
It is 1 mol, preferably 10 ^-4 to 10 ^-1 mol.

For silver halide grains, there is a method of performing noble metal sensitization using a compound that releases noble metal ions such as gold ions. For example, a gold sensitizer is used. As the gold sensitizer, it is preferable to use chloroaurate or an organic gold compound.

Further, in addition to the above-described method of performing chemical sensitization,
Reduction sensitization can also be used, and specific compounds of the reduction sensitizer include ascorbic acid, thiourea dioxide, stannous chloride, hydrazine derivatives, borane compounds, silane compounds, and polyamine compounds. I can do it. Further, reduction sensitization can also be carried out by ripening the emulsion while maintaining the pH of the emulsion at 7 or more or the pAg at 8.3 or less.

The silver halide grains may be chemically sensitized in the presence of an organic silver salt, or may be formed under the condition that no organic silver salt is present.

<Spectral Sensitizer> The silver halide grains can be subjected to spectral sensitization for broadening the photosensitive wavelength using a spectral sensitizing dye. It is preferable to perform spectral sensitization by adsorbing a spectral sensitizing dye on the surface of silver halide grains. Examples of the spectral sensitizing dye include cyanine, merocyanine, complex cyanine, complex merocyanine, holopolar cyanine, styryl, hemicyanine, oxonol, and hemioxonol. For example, JP-A-63-159814 and JP-A-60-14033
No. 5, 63-231437, 63-259651
Nos. 63-304242, 63-15245, U.S. Pat. Nos. 4,639,414 and 4,74.
No. 0,455, No. 4,741,966, No. 4,7
51,175 and 4,835,096 can be mentioned. As useful in the present invention, for example, RD17643, page 23 IV
Spectral sensitizing dyes described or cited in Section A (December 1978) and Section X, p. 18431, 437 (August 1978) are preferred. In particular, it is preferable to use a spectral sensitizing dye having a spectral sensitivity suitable for the spectral characteristics of the light source of various laser imagers and scanners. For example, JP-A-9-34078, JP-A-9-54409, and JP-A-9-806
The compounds described in JP-A-79 are preferably used. When citing a preferred spectral sensitizing dye, as the cyanine dye,
Thiazoline, oxazoline, pyrroline, pyridine, oxazole, thiazole, cyanine dye having a basic nucleus such as selenazole or imidazole nucleus, as a merocyanine dye, in addition to the basic nucleus, thiohydantoin, rhodanine, oxazolidinedione, It is a dye containing an acidic nucleus such as thiazolinedione, barbituric acid, thiazolinone, malononitrile or pyrazolone nucleus. In the present invention, it is particularly preferable to use a spectral sensitizing dye having an absorption wavelength in the infrared region. Examples of preferably used infrared spectral sensitizing dyes include, for example, US Pat. Nos. 4,536,473 and 4,515,888,
No. 4,959,294 can be mentioned. Further, particularly preferred infrared spectral sensitizing dyes are dyes represented by the following formulas (S1) to (S4).

[0142]

Embedded image

Y in the general formulas (S1) to (S4)₁, Y_Two, Y
₁₁, Y_{twenty one}, Y_{twenty two}, Y₃₁, V₁~ V₉, V₁₁~ V₁₃, V_{twenty one}~
V₂₉, V₃₁~ V₃₃, W₁~ W_Four, W₁₁~ W₁₄, W_{twenty one}~
W_{twenty four}, W ₃₁~ W₃₄, Z1, X₁, X₁₁, X_{twenty one}, X₃₁, R
1, r11, r21, r31, k1, k2, k21, k
22, n21, n22, n31, n32, p1, p1
Japanese Patent Application No. 2 for 1, q1, q11, R, Rc and Rd
000-191062, paragraphs (0172) to (017)
It has the same meaning as that described in 9).

Further, among the general formulas (S1) and (S2), more preferred structures are the dyes represented by the following general formulas (S1-1) and (S2-1).

[0145]

Embedded image

Y in general formulas (S1-1) and (S2-1)
_{1, Y 2, Y 11,} Z 1, R, R 1, R 11, W 1 ~W 4, W 11 ~
W ₁₄ , L _{1 to} L ₉ , L _{11 to} L ₁₅ , m1, m2, m3, p
1, p11, q1, q11, X 1, X 11, r1 and r1
No. 1 is described in paragraph (0) of Japanese Patent Application No. 2000-191062.
181) to (0185).

General formulas (S1) to (S4), (S1-1)
And Japanese Patent Application No. 20-210 for compounds represented by (S2-1).
Paragraphs (0187) to (0203) of 00-191062
And the same as those described in the above.

One of these infrared spectral sensitizing dyes is characterized by having a tricyclic fused heterocyclic nucleus in which a nitrogen atom of a benzoazole ring is bonded to a carbon atom at the peri position. One is particularly preferably a long-chain polymethine dye characterized in that a sulfinyl group is substituted on the benzene ring of a benzoazole ring.

The infrared sensitizing dyes described above are, for example, by FM Hammer, The Chemistry of H
eterocyclic Compounds No. 18
Volume, The Cyanine Dyes and Re
rated Compounds (A. Weissbe
rger ed. Published by Interscience, Ne
w York 1964).

The infrared spectral sensitizing dye may be added at any time after the preparation of the silver halide. For example, the infrared spectral sensitizing dye may be added to an organic solvent or dispersed in fine particles in a so-called solid dispersion state.
It can be added to a photosensitive emulsion containing silver halide grains and organic silver salt grains. Further, similarly to the heteroatom-containing compound having an adsorptive property to the silver halide grains, the chemical sensitization may be performed after adding and adsorbing the silver halide grains prior to the chemical sensitization. Dispersion of the chemical sensitization center nucleus can be prevented, and high sensitivity and low fog can be achieved.

<Supersensitizer> The above-mentioned spectral sensitizing dyes may be used alone or in combination, and the combination of spectral sensitizing dyes is particularly useful for supersensitization. Often used.

The photosensitive emulsion containing an organic silver salt containing silver halide grains used in the silver salt photothermographic dry imaging material of the present invention, together with a spectral sensitizing dye, a dye having no spectral sensitizing effect itself, or The silver halide grains may be supersensitized by including a substance which does not substantially absorb visible light as a substance exhibiting a supersensitizing effect in the photosensitive emulsion.

A combination of a spectral sensitizing dye and a supersensitizing dye,
And supersensitizers, RD17643 (1978)
(December), page 23, IV, J, or 9-255
No. 00, No. 43-4933, JP-A-59-19032
No. 59-192242, JP-A-5-341432
As described above, in the present invention, it is preferable that a heteroaromatic mercapto compound or a mercapto derivative compound represented by the following general formula [6] is contained in a photosensitive emulsion as a supersensitizer. .

General Formula [6] Ar-SM In the formula, M is a hydrogen atom or an alkali metal atom;
r is an aromatic or fused aromatic ring having one or more nitrogen, sulfur, oxygen, selenium or tellurium atoms.
Preferably, the heteroaromatic ring is benzimidazole, naphthymidazole, benzothiazole, naphthothiazole,
It is a benzoxazole, naphthoxazole, benzoselenazole, benzotellurazole, imidazole, oxazole, pyrazole, triazole, triazine, pyrimidine, pyridazine, pyrazine, pyridine, purine, quinoline or quinazoline ring. Further, it may contain another heteroaromatic ring.

Incidentally, a mercapto derivative compound which substantially produces the above-mentioned mercapto compound when contained in an organic silver salt dispersion containing silver halide grains is also preferably used in the present invention. In particular, a preferable example is a mercapto derivative compound represented by the following general formula [7].

General formula [7] Ar-SS-Ar In the formula, Ar has the same meaning as in the case of the mercapto compound represented by the general formula [6]. The heteroaromatic ring includes, for example, a halogen atom, a hydroxyl group, an amino group, a carboxyl group, an alkyl group having 1 to 4 carbon atoms, and 1 carbon atom.
It may have a substituent selected from the alkoxy groups of (1) to (4).

In the present invention, in addition to the supersensitizers described above, a compound represented by the following general formula (1) and a macrocyclic compound disclosed in Japanese Patent Application No. 2000-70296 are used as supersensitizers. Can be used.

[0158]

Embedded image

In the general formula (1), T ₃₁ , J ₃₁ , R
For a, Rb, Rc, Rd, H ₃₁ Ar-, M ₃₁ and k31, see paragraph (02) of Japanese Patent Application No. 2000-191062.
16) to (0227).

The supersensitizer is contained in the emulsion layer containing the organic silver salt and the silver halide grains in an amount of 0.001 to 1 mol per mol of silver.
It is preferable to use in a range of 1.0 mol. Particularly preferably, the amount is in the range of 0.01 to 0.5 mol per mol of silver.

[Color Toning Agent] The silver salt photothermographic dry imaging material of the present invention may contain a color toning agent for adjusting the color tone of silver, if necessary, in any of the constituent layers.

In the present invention, examples of the toning agent include R
D17029, U.S. Patent Nos. 4,123,282, 3,994,732, 3,846,136,
The following ones disclosed in the specification of Japanese Patent No. 4,021,249 can be used. Imides; mercaptans; phthalazinone derivatives or metal salts of these derivatives; combinations of phthalazine and phthalic acids; phthalazine and maleic anhydride; and phthalic acid, 2,3-naphthalenedicarboxylic acid or o-phenylene acid derivatives and anhydrides thereof And a combination with at least one compound selected from compounds. Particularly preferred toning agents include
It is a combination of phthalazinone or phthalazine with phthalic acids and phthalic anhydrides.

[Binder] The binder suitable for the constituent layers such as the photosensitive layer, protective layer (outermost layer) and back layer of the silver salt photothermographic dry imaging material of the present invention is transparent or translucent. Colorless, natural, semi-synthetic or synthetic polymers can be used. For example, gelatin, hydroxyethylcellulose, cellulose acetate, cellulose acetate butyrate, polyvinylpyrrolidone, vinyl chloride copolymer, styrene copolymer, polyvinyl acetals (for example, polyvinyl formal, polyvinyl acetal, and polyvinyl acetal) can be mainly used as the binder. Butyral), polyesters, polyurethanes, phenoxy resins, polyvinylidene chloride, polyepoxides, polycarbonates, polyvinyl acetate, cellulose esters, polyamides and the like. Either a hydrophilic binder or a hydrophobic binder can be used depending on the constituent layer. In the present invention, a hydrophobic binder is preferable for the constituent layer, particularly for the photosensitive layer. However, a hydrophilic binder may be used for the protective layer, the back layer, and the like.
The glass transition point (Tg,
(° C)) is preferably 20 to 200 ° C.

The binder for the photosensitive layer according to the present invention is preferably a polyvinyl acetal, for example, polyvinyl acetal, polyvinyl propional, or polyvinyl butyral, and particularly preferably polyvinyl butyral.
Polyvinyl butyral is obtained by reacting butyraldehyde with a partially hydrolyzed product of polyvinyl alcohol or polyvinyl acetate (having a large degree of hydrolysis), and has, as a side chain, a butyral group, a hydroxyl group, In some cases, it has an acetyl group.

[0165]

Embedded image

In the formula, m represents a butyral group, n represents an acetyl group, and p represents a mol% fraction of a hydroxyl group. m +
n + p = 100, m is 40 to 86 mol%, n is 0 to 60 mol%, and p is 0 to 36 mol%. Preferably, m is 50 to 86 mol%, and n is 0 to 40 mol.
% And p is 5 to 25 mol%.

In the non-photosensitive layers such as the protective layer and the back layer, cellulose esters such as cellulose triacetate and cellulose acetate butyrate are preferred. If necessary, the above binders can be used in combination of two or more kinds.

In the photosensitive layer, in order to stably hold the organic silver salt in the binder, the weight ratio of the binder to the organic silver salt is from 15: 1 to 1: 2 (binder: organic silver salt), especially 8 : 1 to 1: 1 is preferred. That is, the amount of the binder in the photosensitive layer is preferably 1.5 to 6 g / m ^2, and more preferably 1.7 to 5 g / m ² . By setting the content within this range, the fog density can be reduced.

[Organic solvent] In the present invention, the organic solvent is
It is mainly used for dissolving the binder and providing it as a coating solution. In addition, it also has a role of dissolving and mixing various additives. Organic solvents useful in the present invention include, for example, acetone, methyl ethyl ketone,
Ketones such as isophorone, alcohols such as methyl alcohol, ethyl alcohol, isopropyl alcohol, cyclohexanol and benzyl alcohol, glycols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol and hexylene glycol, ethylene glycol monomethyl ether, Examples thereof include ether alcohols such as diethylene glycol monoethyl ether, ethers such as isopropyl ether, esters such as ethyl acetate and butyl acetate, chlorides such as methylene chloride and dichlorobenzene, and hydrocarbons. Other water, formamide, dimethylformamide, toluidine, tetrahydrofuran,
Acetic acid and the like can also be used at any time. However, it is not limited to these. These solvents can be used in combination of two or more.

In the present invention, the organic solvent evaporates in the coating and drying step and hardly remains in the silver salt photothermographic dry imaging material. However, it is sometimes preferable that some organic solvent is present, such as development behavior during thermal development, and it is preferable that the organic solvent be contained in an amount of 5 mg to 1000 mg per m ² . The content can be measured by gas chromatography.

[Support] The support used for the silver salt photothermographic dry imaging material of the present invention is preferably a material which can be processed into a flexible sheet or roll for handling as an information recording material. As the support, a plastic film is preferable. Accordingly, as the support used in the present invention, a film having high mechanical strength, heat resistance, and dimensional stability with little expansion and contraction to heat is preferable, and a cellulose acetate film (cellulose triacetate film, cellulose acetate propionate) is preferable. Film, cellulose acetate butyrate film, etc.) Polyester film (polyethylene terephthalate film, polyethylene naphthalate film, etc.), polyamide film, polyimide film and polycarbonate film are preferred. Of these, two
Axial stretched polyester film, especially polyethylene terephthalate (PET) film or polyethylene
2,6-Naphthalate (PEN) films are preferred.
The thickness of the support is about 50 to 300 μm, preferably 70 to 180 μm.

Further, the support may contain a coloring agent such as a dye or a pigment. For the medical silver salt photothermographic dry imaging material, it is preferable to use a blue dye used for a general medical silver halide color photographic light-sensitive material, and a dye having heat resistance and no sublimability is preferable. Examples of such a dye include a diaminoanthraquinone-based dye. Preferred examples include the following blue dye.

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[Surface Treatment of Support] In order to bond the support with constituent layers such as a photosensitive layer, an undercoat layer may be applied to the surface of the support or a surface treatment may be applied. No processing need be performed.

The resins useful for the undercoat layer according to the present invention include acrylate and / or methacrylate copolymers, polyester resins, acrylate-modified polyester resins, polyurethane resins and the like. Examples of the monomer used for the acrylate and / or methacrylate copolymer include alkyl acrylate, alkyl methacrylate, hydroxyalkyl acrylate, hydroxyalkyl methacrylate, phenyl acrylate, phenyl alkyl acrylate, cycloalkyl acrylate, cycloalkyl methacrylate, and other monomers. Examples thereof include styrene, vinyl chloride, vinylidene chloride, acrylonitrile, acrylic acid, methacrylic acid, itaconic acid, butadiene, and isoprene. A latex is formed by emulsion polymerization of these monomers, and the resulting latex is applied as a coating liquid for an undercoat layer to the surface of a support to form an undercoat layer. A similar undercoat layer may be further applied as an upper layer on the undercoat layer. Furthermore,
Before applying the undercoat layer to the support, surface treatment may be performed by corona discharge.

As another subbing layer resin useful in the present invention, a polyester resin and an acrylate-modified polyester resin can be exemplified. As the polyester resin, as a dicarboxylic acid component, terephthalic acid, phthalic acid, 1,4-cyclohexanedicarboxylic acid, 1,4-cyclohexanediacetic acid, adipic acid, sulfophthalic acid, etc.
Examples of the diol component include ethylene glycol, propylene glycol, butylene glycol, diethylene glycol, polyethylene glycol, polypropylene glycol, 1,4-chlorohexanedimethanol, and the like. And polycondensation via transesterification to obtain a polyester resin. Preferred polyester resins for the present invention include 3 as a dicarboxylic acid component.
0-70% by weight of terephthalic acid, 5-15% by weight of 5-
Sodium sulfophthalic acid, 50 to 100% by mass
A water-soluble or water-dispersible polyester resin formed mainly using ethylene glycol is preferred.

The acrylic-modified polyester resin is obtained by polymerizing the above water-soluble or water-dispersible polyester resin in an aqueous medium with a monomer used for the above acrylate and / or methacrylate copolymer using a polymerization initiator. Can be

When the support is a polyester film, an undercoat layer may be applied before and after stretching during the production of the polyester film.

As another method of surface treatment, Japanese Patent Application No. 2000
No. 066778, under atmospheric pressure or at a pressure close to 50% by pressure of the inert gas to be introduced as argon gas at a pressure of or near atmospheric pressure, and hydrocarbon gas and / or fluorohydrocarbon. In the present invention, a surface treatment method for making a support hydrophobic by subjecting it to a discharge plasma treatment in a gas in which a gas containing a reactive gas is continuously conveyed and treated is preferably used. According to this method, the surface treatment can be performed immediately before coating the photosensitive layer without applying a coating such as an undercoat layer, and the constituent layers such as the photosensitive layer can be firmly adhered to the support. This is the preferred method.

[Additives of Constituent Layers Other than Photosensitive Layer] << Antihalation dye >> The silver salt photothermographic dry imaging material according to the present invention may control the amount or wavelength distribution of light transmitted through the photosensitive layer. In order to maintain the sharpness of the image, it is preferable to form a filter layer on the same side as or opposite to the photosensitive layer, or to include a dye or pigment in the photosensitive layer. Known compounds that absorb light in various wavelength ranges according to the color sensitivity of the photosensitive material can be used as the dye.

The silver salt photothermographic dry imaging material of the present invention may have photosensitivity in the range of ultraviolet light, visible light and infrared light. In order to maintain the same, it is preferable that the photosensitive wavelength of the image exposure is in the infrared region. It is preferable to include a dye having an antihalation effect on infrared light in any of the constituent layers. Examples of the antihalation dye effective against infrared rays include, for example, Japanese Patent Application No. 11-25555.
Squarylium dye having a thiopyrylium nucleus (referred to as thiopyrylium squarylium dye) and squarylium dye having a pyrylium nucleus (referred to as pyrylium squarylium dye) as disclosed in No. 7, and thiopyrylium croconium similar to the squarylium dye It is preferable to use a dye or a pyrylium croconium dye.

The compound having a squarylium nucleus refers to 1-cyclobutene-2-hydroxy- in the molecular structure.
A compound having a 4-one and a compound having a croconium nucleus refers to 1-cyclopentene-2- in the molecular structure.
It is a compound having hydroxy-4,5-dione. Here, the hydroxyl group may be dissociated. Hereinafter, in the present specification, these dyes are collectively referred to as a squarylium dye for convenience.

The dyes are described in JP-A-8-201959.
The compounds described in Japanese Patent Application Laid-Open (JP-A) No. 10-284131 are also preferred. << Antistatic, matting agent >> The silver salt photothermographic dry imaging material preferably contains an antistatic agent in either the undercoat layer or the constituent layers. As the antistatic agent, those used in ordinary silver halide color photographic light-sensitive materials can likewise be preferably used. It is preferable to include a conductive compound such as a metal oxide and / or a conductive polymer in a constituent layer, particularly, an antistatic layer (which may be a lower layer of an undercoat layer), a protective layer, and a back layer. Specifically, US Pat. No. 5,244,773, 14
To 20 columns.

In the present invention, the surface layer of the silver salt photothermographic dry imaging material (even when a non-photosensitive layer is provided on the photosensitive layer side or on the side opposite to the photosensitive layer with the support interposed therebetween) is At the time of packaging, a matting agent is preferably contained for the purpose of handling before development and preventing damage to the image after thermal development, and preferably contains 0.1 to 30% by mass of the binder. The material of the matting agent to be used may be either an organic substance or an inorganic substance, but it is better not to avoid an organic substance which may affect the heat development. Examples of the inorganic substance include silica described in Swiss Patent No. 330,158, glass powder described in French Patent No. 1,296,995,
Alkaline earth metals or carbonates such as cadmium and zinc described in GB 1,173,181 can be used as matting agents. Examples of the organic substance include starch particles described in US Pat. No. 2,322,037, starch derivative particles described in Belgian Patent No. 625,451 and British Patent No. 981,198, and Japanese Patent Publication No. Sho 44. -3643, polystyrene or polymethacrylate particles described in Swiss Patent No. 330,158, polyacrylonitrile particles described in U.S. Pat. No. 3,079,257, U.S. Pat. Organic matting agents such as polycarbonate described in JP-A-3,022,169 can be mentioned.

The matting agent preferably has an average particle size of 0.5 to 5 μm, more preferably 1 to 3 μm. The variation coefficient of the particle size distribution is 50%
The matting agent is preferably at most 40%, more preferably at most 40%, particularly preferably at most 30%.

[Silver salt photothermographic dry imaging material]
A silver salt photothermographic dry imaging material is imagewise exposed to light having a photosensitive wavelength possessed by the silver salt photothermographic material, and thermally developed at a predetermined heating temperature to obtain an image. The latent image developed by exposure is 80 to 200 ° C, preferably 100 to 20 ° C.
Develop by heating at 0 ° C. for 1 second to about 2 minutes.
In practice, the organic silver salt releases silver ions more efficiently at around 120 ° C. It is a characteristic of the silver salt photothermographic dry imaging material that when heated, a silver image is generated by an oxidation-reduction reaction between an organic silver salt (functioning as an oxidizing agent) and a reducing agent. This reaction process
The process proceeds without any supply of a processing liquid such as water from the outside.
In such a temperature range, an image having a sufficient optical density can be obtained, and development can be performed without any inconvenience to a developing machine.

The heat development may be carried out using a heat developing machine of a product provided by the manufacturer, or may be a simple heating device, apparatus or means. For example, a hot plate, iron, hot roller, carbon or white It may be performed by a heating means such as a heat generator using titanium or the like. In the thermal development, the surface of the silver salt photothermographic dry imaging material on the photosensitive layer side is preferably heated by uniformly contacting the surface with the above-mentioned heating means.

<Gradation of Silver Halide Photothermographic Dry Imaging Material> In the present invention, the wedge exposure and wedge image are defined as a silver halide photothermographic dry imaging material having an exposure energy logE of 0.1 per step from the maximum output. 05
Exposure is performed in a stepwise manner so as to gradually decrease, and an image in which the optical density is reduced in a stepwise manner from the maximum optical density obtained by thermally developing the wedge thus exposed.

The wedge obtained by subjecting the photosensitive layer of the silver salt photothermographic dry imaging material of the present invention to wedge image exposure and thermally developing at 123 ° C. for 13.5 seconds by the above-mentioned heating means. Minimum optical density (fog density) +0.25 with diffused light in the characteristic curve of the image on the orthogonal coordinates where the optical density with diffused light (Y axis) and the unit length of common log exposure (X axis) are equal. ~ Minimum optical density +
That the average gradation between 2.5 is 2.0 to 4.0,
This is a feature of the present invention according to claim 2. A thermally developed silver salt photothermographic dry imaging material having such an average gradation has a high concentration or high purity of organic silver having a silver concentration of 78-99% by mass using behenic acid. Having a photosensitive layer having a salt and a silver saving agent, preferably having a two- or three-layer structure, wherein at least one layer, particularly silver behenate, which is formed on the lower layer of the multilayer structure And a silver saving agent.
More specifically, taking two layers as an example, the upper layer is a photosensitive layer containing a small amount of organic silver salt or containing silver behenate in the organic silver salt, and the lower layer is the above-described high-concentration or high-purity behenate. By making the photosensitive layer containing silver oxide and a silver saving agent, the upper layer contributes to the foot portion of the characteristic curve (where the tone gradually rises from the fog density portion in the gradation of the low density portion), and the lower layer becomes Helping to create the highest concentration,
Minimum optical density (fog density) at the above diffused light + 0.25
The average gradation between the minimum optical density +2.5 and 2.0-4.
Can be set to 0. The concentration of silver behenate (based on the organic silver salt) added to the upper layer is preferably silver behenate having a content of 40 to 78%. In this case, unpurified silver may be used as it is, but it is preferable to use high concentration or purified behenic acid as described above.

FIG. 1 shows an apparatus for multi-layer coating of a photosensitive composition coating solution and the like. FIG. 1 is a conceptual view showing a multi-layer coating by a three-layer multi-layer extruder coater. 1 is a coating back roll, 2 is a support, 3 is an extruder
A coater, 4 is a lower layer coating liquid slit, 5 is an upper layer coating liquid slit, 6 is an uppermost layer coating liquid slit, and 7 is a coating liquid pool. The coating solution of each layer is sequentially applied to the support 2 through the coating solution slits 4, 5 and 6 from the solution pool 7 of each coating solution.

<Color tones of heat-developed silver salt photothermographic dry imaging material images> Conventionally, with regard to the color tones of output images for medical diagnosis, the cooler image tones are more accurate for radiograph readers. It is said that it is easy to obtain a diagnostic observation result of a recorded image. Here, the cool image tone is a pure black tone or a blue-black tone in which a black image is bluish, and the warm image tone is a warm black tone in which a black image is brownish. Say The term “cooler” for color
And "more temperature control" is the lowest concentration D _{mi n} and optical density D =
It is determined by the hue angle h _{a b} defined by JIS Z 8729 at 1.0. Hue angle _hab is JIS Z8
XYZ color system or tristimulus value X,
JIS Z 87 from Y, Z or X ₁₀ , Y ₁₀ , Z ₁₀
It can be expressed by _hab = tan ^-1 (b ^* / a ^* ) using the color coordinates a ^* and b ^* of the L ^* a ^* b ^* color system defined by 29.

By using the organic silver salt using high-density or high-purity behenic acid and the silver saving agent according to the present invention, the color tone in the image of the low optical density portion becomes a cool image tone, and The hue angle _hab is 180 ° < _hab <2
It turned out to be in the range of 70 °. In the present invention, a more preferable range is 195 ° < _hab <255 °, and a still more preferable range is 200 ° < _hab <250 °, and the silver salt photothermographic dry imaging material of the present invention can achieve this. done. As a result, the low density part of the diagnostic photograph,
In particular, it was found that the recognition ability in the lung mediastinal region was improved.

<Sensitivity Wavelength and Light Source Suitable for Silver Halide Photothermographic Dry Imaging Material> For the exposure of the silver halide photothermographic dry imaging material, it is preferable to use a light source suitable for the color sensitivity imparted to the photosensitive layer. This is important for obtaining a good image. For example, if the photosensitive layer is sensitive to infrared light, if the light source has a wide wavelength in the infrared region, it can be applied to a light source having an emission wavelength in that region. However, in the case of emitting light of almost a single wavelength like a laser, it is necessary to adjust the peak of the color sensitivity of the photosensitive layer to that. Since the power of recent semiconductor lasers is high power, small, and has an emission peak in the near infrared, exposure to infrared semiconductor lasers (780 n
m, 820 nm) can be used as a preferred light source for the silver halide photothermographic dry imaging material of the present invention.

<Image Forming Method of Silver Salt Photothermographic Dry Imaging Material> The silver salt photothermographic dry imaging material of the present invention is a photosensitive material most suitable for laser exposure as described above. Although it can be adopted, it is preferable that the laser beam is laser scanning exposure.

Examples of the laser exposure suitable for the silver salt photothermographic dry imaging material of the present invention include, for example, a laser scanning exposure apparatus in which the angle between the exposure surface of the photosensitive material and the scanning laser beam is not substantially perpendicular. Can be used. Here, the angle which is not substantially perpendicular in the present invention is an angle which is close to vertical but is not perpendicular, and is preferably 55 to 88 °, more preferably 60 to 86 °, and further preferably 65 to 84 °. °, most preferably 70-82 °. The beam spot diameter of the laser beam useful in the present invention is preferably 200 μm or less,
More preferably, it is 10 to 100 μm. This is because a smaller spot diameter is preferable in that the angle of deviation of the laser incident angle from the perpendicular can be reduced, and this also improves the sharpness of the image. By performing such laser scanning exposure, occurrence of interference fringe-like unevenness can be reduced as much as possible, and image quality can be improved.

As another method, the exposure is performed using a laser scanning exposure machine that emits a scanning laser beam that is a multi-scan image. Note that the vertical multi means that the exposure wavelength is not single. In the present invention, the distribution of the exposure wavelength may be 5 nm or more, preferably 10 nm or more. The upper limit of the exposure wavelength distribution is not particularly limited, but is usually about 60 nm. To make vertical multi,
There are a method of using return light by multiplexing, a method of applying high frequency superimposition, and the like, and any of them can be preferably used. With the laser scanning exposure performed in the vertical multi-scanning, image quality deterioration such as occurrence of interference fringe-like unevenness is greatly reduced as compared with the scanning laser light in the optical vertical single mode.

Further, as another method, a method of forming an image by performing scanning exposure using two or more lasers is also preferable. Such an image recording method using a plurality of lasers is based on a demand for high resolution and high speed. The image recording method of a laser printer or a digital copying machine which simultaneously writes a plurality of lines in one scan is used. This method is used in the art.
No. 0-166916 and others. In this method, a laser beam emitted from a light source unit is deflected and scanned by a polygon mirror to form an image on a photoreceptor via an fθ lens or the like. An apparatus using this method is basically a laser imager and a laser imager. The same laser scanning optical device is preferably used for exposing the silver salt photothermographic dry imaging material of the present invention. Specifically, the two light beams are close to each other at an interval of several tens of μm on the image plane in the sub-scanning direction, and have a print density of 400 dpi (in the present invention, 1 inch per 2.54 cm).
The print density of dots is expressed in dpi (dot per inch)
And the pitch in the sub-scanning direction of the two beams is 63.5.
μm, 42.3 μm at 600 dpi. Unlike such a method in which the resolution is shifted in the sub-scanning direction by an amount corresponding to the resolution, two or more lasers are focused at the same location on the exposure surface while changing the incident angle to form an image. At this time, when the exposure energy on the exposure surface when writing with one ordinary laser (wavelength λ [nm]) is E, the N lasers used for exposure have the same wavelength (wavelength λ [nm]). ]), When the same exposure energy (En) is set, 0.9 × E ≦ En × N ≦ 1.
It is preferable to set the range to 1 × E. In the above description, a plurality of lasers have the same wavelength as λ, but lasers having different wavelengths may be used. In this case, (λ−30) <λ1, λ2,... Λn ≦
It is preferable to set it in the range of (λ + 30). As a laser used for scanning exposure, generally well-known solid lasers such as a ruby laser, a YAG laser and a glass laser; He-Ne laser, Ar ion laser,
Kr ion laser, CO ₂ laser, CO laser,
Gas lasers such as He-Cd laser, N ₂ laser, excimer laser; InGaP laser, AlGaAs
s laser, GaAsP laser, InGaAs laser, InAsP laser, CdSnP ₂ laser, Ga
Semiconductor lasers such as Sb lasers; chemical lasers, dye lasers, etc. can be selected and used as appropriate for the application,
Among these, it is preferable to use a semiconductor laser having a wavelength of 600 to 1200 nm from the viewpoint of maintenance and the size of the light source.

In a laser used in a laser imager or a laser imagesetter, the beam spot diameter on the exposed surface of the photosensitive layer when scanning a silver salt photothermographic dry imaging material is generally 5 mm as a minor axis diameter. ~
75 μm, the major axis diameter is in the range of 5 to 100 μm,
The scanning speed of the laser beam can be set to an optimum value by the sensitivity at the laser oscillation wavelength and the laser power specific to the silver salt photothermographic dry imaging material.

[0199]

EXAMPLES The present invention will be described below in detail with reference to examples, but embodiments are not limited thereto.

[Evaluation Method] << Evaluation of Photographic Properties >><AverageGradation> Each sample was left in a room conditioned at 25 ° C. and 55% RH for 10 days after coating. DryPro722
Wedge exposure was performed using (Konica's silver salt photothermographic exposure heat developing machine for dry imaging materials) so that the exposure energy logE was reduced by 0.05 for each step from the maximum output, and the development temperature was 123 ° C. Thermal development was performed with a processing time of 13.5 seconds. Samples obtained by wedge exposure and heat development were measured for density using a PDM65 transmission densitometer (manufactured by Konica) and processed by computer to obtain respective characteristic curves. From these characteristic curves, the minimum optical density (fog density)
The average gradation γ value between +0.25 and the minimum optical density +2.5 was determined.

<Sensitivity> Regarding the sensitivity, from the characteristic curve obtained by wedge exposure and thermal development, density measurement and computer processing in the same manner as in the above-mentioned average gradation item, the minimum optical density (Dmin) is 1.0. Exposure amount E giving a high optical density was determined, and was shown as a relative sensitivity when the sensitivity of the reference sample was set to 100.

<Maximum Optical Density> From the same characteristic curve as above, the maximum optical density value was shown as a relative value when the value of the reference sample was set to 100.

<Fog Density> The minimum optical density (fog density) was numerically shown from the same characteristic curve as above.

<Evaluation of Raw Preservability (Forced aging test in which sample before exposure was subjected to high temperature treatment)> Four samples were prepared for each sample and placed in a closed container kept at 25 ° C. and 55% RH. After placing three of the samples in close contact with each other, the inside of the light-shielding container was kept at 50 ° C., and a forced aging test was performed while maintaining the state for 7 days. One of the three samples was taken out in a light-shielded state and subjected to forced aging. A sample was used. On the other hand, one of the sheets was simply subjected to lapse of time without heat treatment (stored in a light-shielding container at room temperature) to obtain an untreated sample. Draw the above-mentioned characteristic curve for these two samples, measure the fog density of the unexposed part, subtract the fog density of the untreated sample from the fog density of the forced aging sample, and use it as an increase in the fog density, and evaluate the raw storage stability And

<Hue angle h _ab > In the same manner as above, an unprocessed sample is exposed and thermally developed to obtain a characteristic curve. The minimum optical density (Dmin) and the hue of the image at D = 1.0 are calculated as follows.
The hue angle _hab was determined by measuring with a spectral colorimeter CM-508d (manufactured by Minolta) in a 2 ° visual field using a common light source D65 of JIS Z8720 as a light source for color measurement.

Example 1 [Preparation of Subbed Support] <Preparation of PET Subbed Support> Biaxially stretched and heat-fixed manufactured by Konica Corporation at a thickness of 175 μm and an optical density of 0.17
0 (measured with Konica Densitometer PDA-65)
Is subjected to a corona discharge treatment of 0.5 kV · A · min / m ^{2 on} one side of the PET film colored with the blue dye, and then a subbing layer is formed thereon using a subbing coating solution A described below. A was applied so that the dry film thickness was 0.2 μm. Furthermore, 0.5 kV · A · min / m is similarly applied to the other surface.
^After the corona discharge treatment of No. 2, the undercoating coating solution B for the lower layer and the undercoating coating solution A for the upper layer were simultaneously layered thereon, and the dry film thickness was 0.1 μm and 0 μm, respectively. .2 .mu.m to form an undercoat layer B / A. Thereafter, a heat treatment was performed at 130 ° C. for 15 minutes in a heat treatment oven having a film transport device composed of a plurality of roll groups.
The undercoat layer A and the undercoat layer B
/ A is coated with a back layer coating solution.

<Preparation of Undercoat Coating Solution A> A copolymer latex solution (solid content: 30% by mass of n-butyl acrylate, 20% by mass of t-butyl acrylate, 25% by mass of styrene and 25% by mass of 2-hydroxyethyl acrylate) 3
(0%), 270 g, 0.6 g of Compound C-1 and 0.5 g of methylcellulose were mixed. Further, 1.3 g of silica particles (Syloid 350, manufactured by Fuji Silysia Ltd.) was previously dissolved in 100 g of water in an ultrasonic dispersing machine [ALEX Corporation, trade name: Ultrasonic Generator (Ultrasonic).
c Generator), frequency 25 kHz, 600
W] for 30 minutes is added, and finally 10 minutes with water.
It was finished to 00 ml to obtain a subbing coating solution A.

<Preparation of Colloidal Tin Oxide Dispersion> 65 g of stannic chloride hydrate was mixed with a water / ethanol mixed solution 200
The solution was dissolved in 0 ml to prepare a homogeneous solution. Then, it was boiled to obtain a coprecipitate. The resulting precipitate was taken out by decantation and washed several times with distilled water. After confirming that there is no reaction of chlorine ions by dropping silver nitrate into distilled water from which the precipitate has been washed, distilled water is added to the washed precipitate to make the total volume 2000 ml. Further, 40 ml of 30% ammonia water was added, and the aqueous solution was heated to a capacity of 47%.
It was concentrated to 0 ml to prepare a colloidal tin oxide dispersion.

<Undercoat Coating Solution B> 37.5 g of the above colloidal tin oxide dispersion, 20% by mass of n-butyl acrylate, 30% by mass of t-butyl acrylate, and 27% of styrene.
3.7 g of a copolymer latex liquid (solid content 30%) of 28% by mass and 2-hydroxyethyl acrylate 28% by mass,
14.8 g of a copolymer latex liquid (solid content: 30%) of 40% by mass of n-butyl acrylate, 20% by mass of styrene, and 40% by mass of glycidyl methacrylate, and 0.1 g of a compound C-1 as a coating aid were mixed. To 1000 ml to give a subbing coating solution B.

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[Preparation of Photosensitive Composition] << Preparation of Photosensitive Silver Halide Particles >> <Solution A> Phenylcarbamoylated gelatin 88.3 g Compound A (10% aqueous methanol solution) 10 ml Potassium bromide 0.32 g pure water Finish to 5429 ml.

<Solution B> 0.67 mol / l silver nitrate aqueous solution 2635 ml <Solution C> Potassium bromide 51.55 g Potassium iodide 1.47 g Finished with pure water to 660 ml.

<Solution D> Potassium bromide 154.9 g Potassium iodide 4.41 g Iridium chloride (1% solution) 0.93 ml Finished with pure water to 1982 ml.

<Solution E> 0.4 mol / l aqueous solution of potassium bromide The following silver potential control amount <Solution F> Potassium hydroxide 0.71 g Make up to 20 ml with pure water.

<Solution G> 18.0 ml of 56% acetic acid aqueous solution <Solution H> 1.72 g of anhydrous sodium carbonate Make up to 151 ml with pure water.

Here, compound A is HO (CH ₂ CH
₂ O) _n (CH (CH ₃ ) CH ₂ O) ₁₇ (CH ₂ CH ₂ O) _m
H, (m + n = 5-7).

Using a mixing stirrer described in Japanese Patent Publication No. 58-58288, a 1/4 amount of the solution B and a total amount of the solution C were simultaneously mixed in the solution A while controlling the pAg to 8.09 at 45 ° C. It took 4 minutes and 45 seconds to add, and nucleation was performed. One minute later, the entire amount of solution F was added. During this time, pAg was appropriately adjusted using the solution E. After a lapse of 6 minutes, 3/4 of the amount of the solution B and the entire amount of the solution D were added at 45 ° C. and p
14 minutes 1 by the simultaneous mixing method while controlling to Ag 8.09
The addition took 5 seconds. After stirring for 5 minutes, the temperature was lowered to 40 ° C., the whole amount of Solution G was added, and silver halide grains were precipitated. The supernatant was removed, leaving 2000 ml of the sedimented portion, 10 l of water was added, and after stirring, the silver halide grains were sedimented again. The supernatant was removed, leaving 1500 ml of the sedimented portion, and 10 l of water was further added. After stirring, the silver halide grains were sedimented. After removing the supernatant, leaving 1500 ml of the sedimented portion, the solution H was added, and the temperature was raised to 60 ° C.
The mixture was further stirred for 120 minutes. Finally, the pH was adjusted to 5.8, and water was added so as to be 1161 g per 1 mol of silver to obtain a photosensitive silver halide emulsion.

The silver halide grains had an average grain size of 0.058 μm, a grain size variation coefficient of 12%, and [10
0] Monodispersed cubic silver iodobromide grains having an area ratio of 92%.

<< Preparation of Powdered Organic Silver Salt Containing Silver Halide Particles >><Preparation of Powdered Organic Silver Salt A Containing Silver Halide Particles> Organic silver salt particles were prepared using a commercially available reagent of unpurified behenic acid. When this behenic acid was analyzed by the above-mentioned analysis method, the behenic acid content was 80% by mass. Since the rest contained arachidic acid and stearic acid, using arachidic acid, stearic acid and palmitic acid reagents,
Each organic acid reagent was mixed so as to obtain 130.8 g of behenic acid, 67.7 g of arachidic acid, 43.6 g of stearic acid, and 2.3 g of palmitic acid, and the mixture was poured into 4720 ml of pure water and dissolved at 80 ° C. Next, 540.2 ml of 1.5 mol / l sodium hydroxide aqueous solution was added, and 6.9 concentrated nitric acid was added.
After adding ml, the mixture was cooled to 55 ° C. to obtain a mixed sodium fatty acid solution. While keeping the temperature of the mixed fatty acid sodium solution at 55 ° C. in a light-blocked state (hereinafter, the light-blocked state is continued), 45.3 g of the silver halide emulsion and 450 ml of pure water were added and added for 5 minutes. Stirred. Then 1
702.6 ml of a mol / l silver nitrate aqueous solution was added over 2 minutes and stirred for 10 minutes to obtain a silver halide particle-containing organic silver salt particle dispersion A. Thereafter, the obtained organic silver salt particle dispersion A containing silver halide particles is transferred to a washing vessel, deionized water is added, and the mixture is stirred and allowed to stand to float the organic silver salt particle dispersion A containing silver halide particles. Separate and remove the lower water soluble salts. After that, the conductivity of the wastewater is 2 μS / c.
m, washing with deionized water and draining repeatedly until
Centrifugal dehydration was performed to obtain cake-like organic silver salt particles A containing silver halide particles. The organic silver salt particles A containing the cake-like silver halide particles were subjected to a water content of 0 using a flash-type drier flash jet drier (manufactured by Seishin Enterprise Co., Ltd.) according to the operating conditions of the nitrogen gas atmosphere and the hot air temperature at the dryer entrance. Drying was carried out to 0.1% to obtain a powdered organic silver salt A containing silver halide particles. An infrared moisture meter was used to measure the water content of the powdered organic silver salt A containing silver halide particles. The amount of behenic acid in the powdered organic silver salt A containing silver halide particles was quantified by the above-mentioned analysis method, and the ratio of silver behenate contained in the organic silver salt particles A was 54% by mass. The results of analysis of the mixed organic acids were as follows.
m and the iodine value were 1.5.

<Preparation of Powdered Organic Silver Salt B Containing Silver Halide Particles> 150.0 g of behenic acid and 78.0 of arachidic acid
g and 20.7 g of stearic acid, and a silver halide particle-containing organic silver salt B was prepared in exactly the same manner as the silver halide particle-containing organic silver salt A except that the dissolution temperature was 90 ° C. did. The amount of silver behenate in the powdered organic silver salt B containing silver halide particles was quantified by the above-mentioned analytical method, and the ratio of silver behenate contained in the organic silver salt particles B was 60% by mass.
Met.

<Preparation of Powdered Organic Silver Salt C Containing Silver Halide Particles> A commercially available high-concentration behenic acid was used.
7.0 g, arachidic acid 20.0 g, stearic acid 1
7.3 g and a powder organic silver salt C containing silver halide particles was prepared in exactly the same manner as for the organic silver salt A containing silver halide particles except that the dissolution temperature was 90 ° C. The amount of silver behenate in the powdered organic silver salt C containing silver halide particles was quantified by the above-mentioned analysis method, and the ratio of silver behenate contained in the organic silver salt particles C was 85% by mass. The heavy metal content is 3.
5 ppm and an iodine value of 0.8.

<Preparation of Powdered Organic Silver Salt D Containing Silver Halide Particles> An unpurified behenic acid reagent was recrystallized once with toluene. As a result of analysis, it was confirmed that behenic acid whose content was increased to 92% by mass was 258. Using 0 g (of which 8 mass% contained arachidic acid), an organic acid prepared to be 217.0 g of behenic acid, 20.0 of arachidic acid, and 17.3 g of stearic acid was used. Was changed to 90 ° C. to prepare a powdery organic silver salt D containing silver halide particles in the same manner as in the case of the organic silver salt A containing silver halide particles. The amount of silver behenate in the powdered organic silver salt D containing silver halide particles was quantified by the above-mentioned analysis method, and the ratio of silver behenate contained in the organic silver salt D was 85% by mass. The heavy metal content is 2
ppm and iodine value were 0.5.

<Preparation of Powdered Organic Silver Salt E Containing Silver Halide Particles> An unpurified behenic acid reagent was recrystallized three times with toluene. As a result of analysis, it was confirmed that behenic acid whose content was increased to 98% by mass was 259. 3 g (2% by mass contained arachidic acid), and except that the dissolution temperature was 90 ° C., in the same manner as the silver halide particle-containing powdered organic silver salt A, except that the melting temperature was 90 ° C. E was produced. The amount of silver behenate in the powdered organic silver salt E containing silver halide particles was quantified by the above-mentioned analysis method, and the ratio of silver behenate contained in the organic silver salt E was 98% by mass. The heavy metal content is 2 ppm
Hereinafter, the iodine value was 0.3.

<Preparation of Powdered Organic Silver Salt F Containing Silver Halide Particles> The purified behenic acid used for the organic silver salt E containing silver halide particles was used, and 130.8 g of behenic acid was used.
Powdered organic silver salt containing silver halide particles in the same manner as silver halide particle-containing organic silver salt A except that arachidic acid was prepared at 67.7 g and stearic acid at 43.6 g, and the dissolution temperature was 90 ° C. F was produced. The amount of silver behenate in the powdered organic silver salt F containing silver halide particles was quantified by the above-described analysis method, and the ratio of silver behenate contained in the organic silver salt F was 54% by mass.

<< Preparation of Photosensitive Emulsion >> Butvar B-
79 (Polyvinyl butyral manufactured by Monsanto)
14.57 g was dissolved in 1457 g of methyl ethyl ketone, 500 g of a powdery silver halide containing silver halide particles-containing organic silver salt A was gradually added and stirred sufficiently with a dissolver DISPERMAT CA-40M (manufactured by VMA-GETZMANN), and the mixture was sufficiently mixed. A media type disperser DISPERMAT SL-C filled with 0.5% zirconia beads (manufactured by Toray Industries, Inc .: Treceram) so that the residence time in the mill is 1.5 minutes.
The emulsion was supplied to a 12EX type (manufactured by VMA-GETZMANN) and dispersed at a mill peripheral speed of 8 m / sec to prepare a photosensitive emulsion A. Powdered organic silver salts B and C containing silver halide grains,
Similarly, photosensitive emulsions B, D and E
C, D, E and F were prepared.

<< Preparation of Stabilizer Liquid >> 1.0 g of Stabilizer-1
And 0.31 g of potassium acetate in 4.97 g of methanol
To prepare a stabilizer solution.

<< Preparation of Infrared Sensitizing Dye Liquid >> 19.2 mg of infrared sensitizing dye (SD-1), 1.488 g of 2-chloro-benzoic acid, 2.779 g of stabilizer-2 and 365 mg
5-methyl-2-mercaptobenzimidazole in 3
It was dissolved in 1.3 ml of methyl ethyl ketone in a dark place to prepare an infrared sensitizing dye solution.

[0228]

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<< Preparation of Additive Liquid a >> 1,1 as a reducing agent
27.98 g and 1.54 g of 1-bis (2-hydroxy-3,5-dimethylphenyl) -2-methylpropane
4-Methylphthalic acid, 0.48 g of infrared dye-1 was dissolved in 110 g of methyl ethyl ketone to prepare an additive liquid a.

[0230]

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<< Preparation of Additive Liquid b >> 3.56 g of antifoggant-2 and further 3.43 g of phthalazine were dissolved in 40.9 g of methyl ethyl ketone to obtain an additive liquid b.

[0232]

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<< Preparation of Additive Solution c >> 5.0 g of a silver saving agent (H-94, H-1-5 and 16-1 shown in Table 1) were separately dissolved in 45.0 g of methyl ethyl ketone. An additive liquid c was obtained. In addition, each additive liquid c was set to c1, c2, and c3 in the above order.

[0234]

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In an inert gas atmosphere (nitrogen: 97%), 50 g of the photosensitive emulsion A and 15.11 g of methyl ethyl ketone were kept at 21 ° C. while stirring, and a chemical sensitizer S-5 (0.5% methanol) was added. Solution) (1000 μl), and 2 minutes later, 390 μl of antifoggant-1 (10% methanol solution) was added, followed by stirring for 1 hour. Furthermore, after adding 494 μl of calcium bromide (10% methanol solution) and stirring for 10 minutes, a gold sensitizer Au-5 corresponding to 1/20 mol of the chemical sensitizer was added and further stirred for 20 minutes.
Subsequently, 167 ml of the above stabilizer solution was added and stirred for 10 minutes, and then 1.32 g of the above infrared sensitizing dye solution was added and stirred for 1 hour. Thereafter, the temperature was lowered to 13 ° C., and the mixture was further stirred for 30 minutes. While keeping the temperature at 13 ° C, add Bu
After adding 13.31 g of tvarB-79 and stirring for 30 minutes, 1.084 g of tetrachlorophthalic acid (9.4% methyl ethyl ketone solution) was added and stirred for 15 minutes.
While further stirring, 12.43 g of additive liquid a,
1.6 ml of a 10% solution of Desmodur N3300 in methyl ethyl ketone, 4.27 g of the above additive solution b and additive solution c (Table 1 for each of the separate photosensitive composition coating solutions)
The additive solutions c1, c2 and c3) of the silver saving agent described in
By adding 0.0 g and stirring, a photosensitive composition coating liquid A was obtained. Further, the above-mentioned photosensitive emulsions B, C, D and E were prepared in the same manner to obtain photosensitive composition coating solutions B, C, D and E. A photosensitive composition coating solution A1 was prepared by removing the silver saving agent from the photosensitive composition coating solution A. Further, photosensitive composition F was prepared in the same manner as photosensitive composition coating liquid A1 containing no silver saving agent.

[0236]

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[Preparation of Surface Protective Layer Coating Solution] << Preparation of Matting Agent Dispersion >> CAB171-15 (Eas
7.5 g of cellulose acetate butyrate (manufactured by tman Chemical Co.)
g of Super-Pflex200.
5 g (calcium carbonate manufactured by Specialty Minerals) was added, and the mixture was dispersed with a dissolver-type homogenizer at 8000 rpm for 30 minutes to prepare a matting agent dispersion.

While stirring 865 g of methyl ethyl ketone, 96 g of CAB171-15 and paraloid A-21 were added.
(Rohm & Haas Co. of polymethyl methacrylate) to 4.5g, HD-1 ((CH 2 = CHSO 2 CH 2) 2 CH
OH), 1.0 g of benzotriazole, and 1.0 g of Surflon KH40 (fluorinated surfactant) were added and dissolved. Next, 30 g of the matting agent dispersion was added and stirred to prepare a coating solution for the surface protective layer.

[Preparation and Coating of Coating Solution for Back Layer] <Preparation of Coating Solution for Back Layer> 830 g of methyl ethyl ketone
While stirring, CAB381-20 (Eastman)
84.2 g of cellulose acetate butyrate (Chemical Co.) and VitelPE2200B (Bo
4.5 g of a polyester resin manufactured by Stic Co.)
Dissolved. Next, 0.30 g of the above-mentioned infrared dye-1 was added to the dissolved solution, and further 4.5 g of Surflon KH40 (a fluorosurfactant manufactured by Asahi Glass Co., Ltd.) dissolved in 43.2 g of methanol and MegaFag F120K. 2.3 g of a (fluorinated surfactant manufactured by Dainippon Ink and Chemicals, Inc.) was added, and the mixture was sufficiently stirred until dissolved. Finally, syloid 64X6000 (WR Grac) dispersed in methyl ethyl ketone at a concentration of 1% by mass and dispersed with a dissolver-type homogenizer.
75 g of silica (manufactured by Company e) was added and stirred to prepare a back layer coating solution.

<Formation of Back Layer> The back layer coating solution thus prepared was applied to the undercoat layer B /
Coating and drying were performed on A using an extrusion coater so that the dry film thickness became 3.5 μm. Drying was performed for 5 minutes using a drying air having a drying temperature of 100 ° C. and a dew point of 10 ° C.

[Preparation of Silver Salt Photothermographic Dry Imaging Material] On the undercoat layer A on the opposite side of the PET support coated with the back layer, the photosensitive composition coating solutions A, B, C and D
And E, and the surface protective layer coating solution on them were coated simultaneously with the extruder coater shown in FIG. Here, the coating amount of each photosensitive composition was adjusted to 1.2 g / m ² and the coating amount of the surface protective layer was adjusted to 2.5 μm. Then, a dry air having a dry bulb temperature of 50 ° C. and a dew point temperature of 10 ° C. was applied to the coated surface and dried for 10 minutes. 100 to 109 were produced. In addition, the sample No. prepared from the photosensitive composition coating liquid A was used. 100 was set as a reference sample.

[Exposure and thermal development treatment] A semiconductor laser which had been subjected to a vertical multi-mode with a wavelength of 800 to 820 nm by the method described in Japanese Patent Application No. 11-157660 was used as an exposure source on the photosensitive layer side of each sample. Exposure was provided by laser scanning. At this time, an image-like latent image was formed by setting the angle between the surface protective layer surface and the exposure laser beam to 75 degrees.

Thereafter, Dry P having a heat drum
Ro722 was subjected to heat development at 123 ° C. for 13.5 seconds using a modified exposure heat developing machine so that the surface protective layer surface on the photosensitive layer side and the heat drum surface were in contact with each other. The exposure and heat development were performed in a room conditioned at 23 ° C. and 50% RH. The obtained images were evaluated as follows.

[0244]

[Table 1]

(Results) As is clear from the table, the silver salt photothermographic dry imaging material samples 105 to 10 of the present invention were obtained.
No. 9 shows that the fog density is low, the sensitivity is about 10% higher, the maximum optical density is considerably high, and the raw preservability is excellent. On the other hand, sample 10 having a low behenic acid concentration
In Nos. 1 and 103, not only the maximum optical density was not increased even when the silver saving agent was added, but also the fog density and raw storage stability were extremely reduced. Samples 102 and 104 to which no silver saving agent was added did not differ significantly from the reference.

Example 2 Photosensitive emulsions A and F were prepared except that no silver saving agent was added.
In the same manner as in Example 1, photosensitive composition coating solutions A1 and F were prepared. The photosensitive composition coating liquids A, B, C, D, and E are the lower photosensitive composition coating liquid, the photosensitive composition coating liquids A1 and F are the upper photosensitive composition coating liquid, and the surface is further coated thereon. The protective layer coating solution was applied to the undercoat layer A on the side opposite to the back layer formed in Example 1 using an extruder coater for a three-layer multilayer as shown in FIG. Simultaneous multi-layer coating was performed using the combination and the amount of silver added. Subsequently, using a drying air having a drying temperature of 50 ° C and a dew point temperature of 10 ° C,
After drying for 10 minutes, silver salt photothermographic dry imaging material sample no. 200 to 208 were produced. Example 1
Sample No. 100 was used as a reference sample.

[0247]

[Table 2]

As is clear from the table, the silver salt photothermographic dry imaging material samples 204 to 208 of the present invention have a low fog density, a sensitivity of about 20%, and a maximum optical density of 20% or more. In particular, it was found that the raw preservability was remarkably excellent. On the other hand, in the comparative samples, 100, 200 and 202 to which no silver saving agent was added, the fog density did not decrease, the sensitivity was almost unchanged,
The average gradation is low, and the hue angle at the minimum optical density is 180.
It was below. Samples 201 and 203 containing the silver saving agent improved the maximum optical density by about 10%, but the sensitivity was hardly changed, and the average gradation was the same as that of the sample of the present invention. The raw preservability deteriorated remarkably, and the minimum optical density was also inferior. Thus, good results can be obtained even when two photosensitive layers are coated and the lower layer uses the silver behenate and the silver saving agent according to the present invention and the upper layer uses ordinary silver behenate. Was completed. Furthermore, the use of the behenic acid gain in the upper layer according to the present invention gave the best results.

[0249]

According to the present invention, high sensitivity, high maximum optical density,
It is possible to obtain a silver salt photothermographic dry imaging material which has good gradation and image with a cool black tone, less fog, and excellent raw preservability, especially for medical image setters. Can provide a silver salt photothermographic dry imaging material.

[Brief description of the drawings]

FIG. 1 is a conceptual view showing a multi-layer coating performed by a three-layer multi-layer extruder coater.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 coating back roll 2 support 3 extruder / coater 4 lower layer coating liquid slit 5 upper layer coating liquid slit 6 uppermost layer coating liquid slit 7 coating liquid pool

Claims (5)

[Claims] An organic silver salt particle, a photosensitive emulsion containing photosensitive silver halide particles and an organic solvent, a photosensitive composition containing a reducing agent and a binder, and a non-photosensitive composition containing a binder are respectively supported. In a silver salt photothermographic dry imaging material coated on the body to form a photosensitive layer and a non-photosensitive layer, all of the organic silver salts have a precision of 78 to
A silver salt photothermographic dry imaging material containing 99% by mass of silver behenate and at least one of the photosensitive layer and the non-photosensitive layer contains a silver saving agent. 2. A photosensitive emulsion containing organic silver salt particles, photosensitive silver halide particles and an organic solvent, a photosensitive composition containing a reducing agent and a binder, and a non-photosensitive composition containing a binder. In a silver salt photothermographic dry imaging material coated on the body to form a photosensitive layer and a non-photosensitive layer, all of the organic silver salts have a precision of 78 to
It contains 99% by mass of silver behenate, and at least one of the photosensitive layer and the non-photosensitive layer contains a silver saving agent, and is subjected to wedge exposure at a temperature of 123 ° C. for 13.5 hours.
The wedge image obtained by heat development in seconds has a minimum value of the diffused light in a characteristic curve shown on a rectangular coordinate having the same unit length of the optical density (Y-axis) in diffused light and the unit length of common log exposure (X-axis). A silver salt photothermographic dry imaging material, characterized in that the average gradation between optical density (fog density) +0.25 and minimum optical density + 2.5 is 2.0 to 4.0. 3. The silver salt photothermographic dry imaging material according to claim 1, wherein the total amount of silver per 1 m ^{2 of the} photosensitive layer is 1.0 to 1.7 g. 4. The silver salt photothermographic dry imaging material according to claim 1, which has two or more photosensitive layers on a support. 5. A hue angle h of an image after exposure and thermal development.
_ab (JIS Z8729 standard), 180 ° <h _ab <2
The silver salt photothermographic dry imaging material according to any one of claims 1 to 4, wherein the angle is 70 °.