JP2007017669A - Silver salt photothermographic dry imaging material and image forming method using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a silver salt photothermographic dry imaging material having high sensitivity and low fog in spite of a small amount of silver, and improved in image preservability in long-term storage, image tone and density unevenness, and also to provide an image forming method using the same. <P>SOLUTION: The silver salt photothermographic dry imaging material has, on a support, a photosensitive layer containing non-photosensitive silver salt of aliphatic carboxylic acid particles, photosensitive silver halide grains, a reducing agent for silver ions and a binder, wherein the non-photosensitive silver salt of aliphatic carboxylic acid particles have a number average particle diameter of 0.01-0.60 μm, and two or more polymer compounds are contained as the binder. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a silver salt photothermographic dry imaging material (photothermographic dry imaging material, photothermographic material, photothermographic material, simply referred to as photothermographic material or photosensitive material) and an image forming method using the same.

  In recent years, imaging (image forming) materials are required to satisfy not only performance such as sensitometry characteristics, image quality characteristics, and ease of handling, but also safety and environmental preservation. In particular, since the ocean dumping of development processing waste liquid has been completely banned, the need from wet processing to dry processing has become remarkable in the fields of medical treatment and printing plate making.

  On the other hand, in the medical field, due to recent digitization of medical information, medical diagnosis images have become mainstream techniques such as MRI (Magnetic Resonance Imaging), CT (Computed Tomography), CR (Computed Radiography), etc. A dry imager system for medical imaging has been used. Also in the field of printing plate making, similar digitization and drying are progressing.

  Along with the above-mentioned social and market trends, photothermographic dry imaging materials that are capable of efficient exposure, such as laser imagers and laser imagesetters, and that can form clear images with high resolution. With increasing importance, there is a need for further improvements in the material. Silver salt photothermographic dry imaging materials have been known for a long time from US Pat. No. 3,152,904, US Pat. No. 3,457,075 and the like.

  In recent years, there has been a demand for downsizing of laser measurers and the like as heat development apparatuses and quick processing. In order to obtain a sufficient density of heat-developable material even if rapid processing is performed, using silver halide grains having a small average grain size, increasing the number of development points, or increasing the covering power, or the second grade A method using a highly active reducing agent having a tertiary alkyl group or a development accelerator such as a phenol compound, a hydrazine compound or a vinyl compound has been proposed (see, for example, Patent Documents 1 and 2).

  However, the covering power (the ability to block the light of the image silver, where the diffusion density of the silver image is D and the amount of silver per unit area is M is defined as covering power = D / N. “Silver covering power” When silver halide grains having a small average grain size are simply used to reduce the dispersion stability of the silver halide grains, the covering power may be lowered, or the image transparency may be reduced. As a result, there is a problem that the haze at the low concentration portion deteriorates. Furthermore, when these techniques are used, the density change increases due to photodegradation (printout) silver or the like during long-term storage after heat development processing, and the silver tone of the resulting image is a conventional wet development type photosensitive material. There arises a problem that it is greatly different from the silver tone of the image obtained from (for example, yellowish). Further, when silver halide grains having a small average grain size are used, there is a new problem that the color tone is reddish in a high density portion having a density of 2.0 or more.

  To solve the above problems, a technique for adjusting the silver tone using a coupler or a leuco dye has been disclosed (see, for example, Patent Documents 3, 4, and 5). When the amount of the leuco dye used is increased, fogging increases during long-term storage, and thus there is a problem that the desired silver tone cannot be adjusted.

It is also disclosed to improve the fog with a binder. (For example, refer to Patent Documents 6 and 7.) However, although some fog improving effects are observed, there are problems such as density unevenness during coating and drying, and deterioration of drying properties, resulting in reduced productivity.
JP-A-11-295844 JP-A-11-352627 Japanese Patent Laid-Open No. 11-288057 Japanese Patent Laid-Open No. 11-231460 JP 2001-264926 A JP 2002-182332 A JP 2002-201215 A

  The object of the present invention has been made in view of the above-mentioned problems, and the object is to improve image storability, image color tone, and density unevenness during long-term storage with high sensitivity and low fog while the amount of silver is small. Another object of the present invention is to provide a silver salt photothermographic dry imaging material and an image forming method using the same.

  The above object of the present invention has been achieved by the following constitutions.

(Claim 1)
A silver salt photothermographic dry imaging material having a photosensitive layer containing a non-photosensitive aliphatic carboxylic acid silver salt particle, a photosensitive silver halide particle, a silver ion reducing agent, and a binder on a support. Silver salt photothermographic photographs, wherein the aliphatic carboxylate silver salt particles have a number average particle size of 0.01 μm or more and 0.60 μm or less, and contain two or more polymer compounds as the binder. Dry imaging material.

(Claim 2)
The silver salt photothermographic dry imaging material according to claim 1, wherein at least one of the binders has a glass transition temperature (Tg) of 70 ° C. or higher and 250 ° C. or lower.

(Claim 3)
3. The silver salt photothermographic dry imaging material according to claim 1, wherein at least one of the binders is a polymer compound having a mass average molecular weight of 10,000 or more and 80,000 or less.

(Claim 4)
The silver salt photothermographic dry imaging material according to any one of claims 1 to 3, wherein at least one of the binders is a polymer compound having a mass average molecular weight of 300,000 to 1,500,000 or less. .

(Claim 5)
5. The silver salt photothermographic dry imaging material according to claim 1, wherein an organic volatile substance contained in at least one of the binders is 500 ppm or less.

(Claim 6)
The silver salt photothermographic dry imaging material according to any one of claims 1 to 5, wherein at least one of the binders contains an antioxidant.

(Claim 7)
The silver salt photothermographic dry imaging material according to any one of claims 1 to 6, wherein at least one of the polymer compounds contained as the binder is a polyvinyl acetal resin.

(Claim 8)
The non-photosensitive aliphatic carboxylic acid silver salt particles are obtained by mixing an organic acid metal salt soap formed by adding an alkali metal salt other than sodium to an aliphatic carboxylic acid and a water-soluble silver compound. The silver salt photothermographic dry imaging material according to any one of claims 1 to 6, wherein the silver salt photothermographic dry imaging material is an acid silver salt particle.

(Claim 9)
The ratio of the photosensitive silver halide grains having a particle size of 0.01 μm or more and 0.05 μm or less to the total amount of the photosensitive silver halide grains is 50% by mass or more in terms of silver, and 8. The silver salt photothermographic dry imaging material according to any one of 1 to 7, wherein the photosensitive aliphatic carboxylic acid silver salt particles have a number average particle diameter of 0.01 μm or more and 0.60 μm or less.

(Claim 10)
The silver salt photothermal energy according to any one of claims 1 to 8, wherein 80% by mass or more and 99.9% by mass or less of the non-photosensitive aliphatic carboxylic acid silver salt particles are silver behenate. Photo dry imaging material.

(Claim 11)
The silver salt photothermographic dry imaging material according to claim 1, comprising a compound that develops cyan during development.

(Claim 12)
The silver salt photothermographic dry imaging material according to any one of claims 1 to 11, wherein the coated silver amount is 0.5 g / m ² or more and 1.5 g / m ² .

(Claim 13)
An image forming method, wherein an image is formed by a laser imager using the silver salt photothermographic dry imaging material according to claim 1.

  According to the above configuration of the present invention, a silver salt photothermographic dry imaging material having high sensitivity, low fog, and improved image storability, image color tone, and density unevenness during long-term storage with a small amount of silver, and the same are used. An image forming method can be provided.

  Hereinafter, the present invention and components of the present invention will be described.

(Organic silver salt particles)
Organic silver salt particles according to the present invention (hereinafter also referred to as non-photosensitive organic silver salt or simply “organic silver salt”. Alternatively, “non-photosensitive aliphatic carboxylic acid silver salt particles” or “aliphatic carboxylic acid silver salt particles” Is also a non-photosensitive organic silver salt that can function as a supply source for supplying silver ions for forming a silver image in the photosensitive layer of the silver salt photothermographic dry imaging material.

  That is, the organic silver salt according to the present invention was heated to 80 ° C. or higher in the presence of photosensitive silver halide grains (photocatalyst) having a latent image formed by exposure on the grain surface and a reducing agent. In the thermal development process, the silver salt functions as a silver ion supply source and can supply silver ions and contribute to silver image formation.

  As such a non-photosensitive organic silver salt, conventionally, silver salts of organic compounds having various chemical structures are known. For example, paragraphs “0048” to “0049” of JP-A-10-62899, European Patent Application Publication No. 803,764A1, page 18, line 24 to page 19, line 37, European Patent Application Publication No. 962,812A1, Japanese Patent Application Laid-Open No. 11-349591, Japanese Patent Application Laid-Open No. 2000- 7683, 2000-72711, 2002-23301, 2002-23303, 2002-49119, 196446, European Patent Application No. 1246001A1, European Patent Application Publication No. 1258775A1, JP 2003-140290 A, JP 2003-195445 A, 2003-295378, JP same 2003-295379, JP same 2003-295380 JP, are described in the 2003-295381 Patent Publication.

  In the present invention, various known organic silver salts can be used. However, it is preferable to use a silver salt of a long chain aliphatic carboxylic acid having 10 to 30, preferably 15 to 25 carbon atoms. Examples of suitable silver salts include the following.

  Examples thereof include silver salts such as behenic acid, stearic acid, arachidic acid, palmitic acid, and lauric acid, and preferable silver salts include silver behenate, silver arachidate, and silver stearate.

  In the present invention, it is preferable that two or more kinds of aliphatic carboxylic acid silver salts are mixed in order to improve developability and form a silver image having a high density and a high contrast. It is preferable to prepare by mixing a silver ion solution with an aromatic carboxylic acid mixture.

  On the other hand, from the viewpoint of the storage stability of the image after development, the melting point of the aliphatic carboxylic acid which is a raw material for the aliphatic carboxylate silver is 50 ° C or higher, preferably 60 ° C or higher. The content ratio is preferably 50% or more, preferably 70% or more, and more preferably 80% or more. From this viewpoint, specifically, it is preferable that the content of silver behenate is high.

  The aliphatic carboxylic acid silver salt is obtained by mixing a water-soluble silver compound and a compound that forms a complex with silver, and is described in Japanese Patent Application Laid-Open No. 9-127643. The controlled double jet method as described above is preferably used. For example, an alkali metal salt (eg, sodium hydroxide, potassium hydroxide, etc.) is added to an organic acid to produce an organic acid alkali metal salt soap (eg, sodium behenate, sodium arachidate), and then a controlled double jet. According to the method, the soap and silver nitrate are mixed to produce an aliphatic carboxylic acid silver salt crystal. At that time, seed crystal grains of silver aliphatic carboxylate, silver halide grains, and the like may be mixed.

[Types of alkali metal salts]
Examples of the types of alkali metal salts that can be used in the present invention include sodium hydroxide, potassium hydroxide, and lithium hydroxide. Among these, it is preferable to use one kind of alkali metal salt, for example, potassium hydroxide, but it is also preferable to use sodium hydroxide and potassium hydroxide in combination. The combined ratio is preferably such that the molar ratio of both of the above-mentioned hydroxide salts is in the range of 10:90 to 75:25. When used in the above range when reacted with an aliphatic carboxylic acid to form an alkali metal salt of an aliphatic carboxylic acid, the viscosity of the reaction solution can be controlled in a good state.

  In addition, when preparing an aliphatic carboxylate silver salt in the presence of silver halide grains having an average particle diameter of 0.050 μm or less, the alkali metal of the alkali metal salt is preferably a halide having a higher potassium ratio. It is preferable because dissolution of silver particles and Ostwald ripening are prevented. Moreover, the size of fatty acid silver salt particle | grains can be made small, so that the ratio of potassium salt is high. A preferable ratio of the potassium salt is 50 to 100% based on the total alkali metal salt used in the step of producing the aliphatic carboxylate. The concentration of the alkali metal salt is preferably 0.1 to 0.3 mol / 1000 ml.

[High silver conversion rate silver salt particles]
The emulsion containing the aliphatic carboxylic acid silver salt grains according to the present invention is a mixture of a free aliphatic carboxylic acid and an aliphatic carboxylic acid silver salt that do not form a silver salt, but the former ratio is relative to the latter. Low is preferable from the viewpoint of image storage stability and the like. That is, the emulsion according to the present invention preferably contains 3 to 10 mol% of an aliphatic carboxylic acid with respect to the aliphatic carboxylic acid silver salt grains. Particularly preferably, the content is 4 to 8 mol%.

  Specifically, by determining the total aliphatic carboxylic acid amount and the free aliphatic carboxylic acid amount by the following method, respectively, the aliphatic carboxylic acid silver salt and the free aliphatic carboxylic acid amount and the respective ratios or The ratio of free fatty acid to total aliphatic carboxylic acid is calculated.

(Quantification of total aliphatic carboxylic acid content (total of those derived from both the above aliphatic carboxylic acid silver salts and free acids))
(1) About 10 mg of sample (the mass removed when peeling from the photosensitive material) is accurately weighed and placed in a 200 ml eggplant type flask.
(2) Add 15 ml of methanol and 3 ml of 4 mol / L hydrochloric acid and ultrasonically disperse for 1 minute.
(3) Put a Teflon (registered trademark) zeolite and reflux for 60 minutes.
(4) After cooling, add 5 ml of methanol from the top of the cooling tube, and wash the material adhering to the cooling tube into the eggplant-shaped flask (twice).
(5) The obtained reaction solution is extracted with ethyl acetate (100 ml of ethyl acetate and 70 ml of water are added and liquid separation extraction is performed twice).
(6) Vacuum dry at room temperature for 30 minutes.
(7) Add 1 ml of benzanthrone solution as an internal standard to a 10 ml volumetric flask (dissolve about 100 mg of benzanthrone in toluene and make up to 100 ml with toluene).
(8) Dissolve the sample in toluene and put it in the volumetric flask of (7), and make a constant volume with toluene.
(9) Perform gas chromatography (GC) measurement under the following measurement conditions.

Apparatus: HP-5890 + HP-Chemical station Column: HP-1 30 m × 0.32 mm × 0.25 μm (manufactured by HP)
Inlet: 250 ° C
Detector: 280 ° C
Oven: constant 250 ° C. Carrier gas: He
Head pressure: 80 kPa
[Quantification of free aliphatic carboxylic acid content]
(1) About 20 mg of a sample is accurately weighed, placed in a 200 ml eggplant-shaped flask, 10 ml of methanol is added, and ultrasonic dispersion is performed at 25 ° C. for 1 minute (free organic carboxylic acid is extracted).
(2) It is filtered, and the filtrate is put into a 200 ml eggplant type flask and dried (free organic carboxylic acid is separated).
(3) Add 15 ml of methanol and 3 ml of 4 mol / L hydrochloric acid and perform ultrasonic dispersion for 1 minute.
(4) Put a Teflon (registered trademark) boiling stone and reflux for 60 minutes.
(5) 60 ml of water and 60 ml of ethyl acetate are added to the resulting reaction solution, and the methyl esterified product of organic carboxylic acid is extracted into the ethyl acetate phase. Ethyl acetate extraction is performed twice.
(6) The ethyl acetate phase is dried and vacuum dried for 30 minutes.
(7) Add 1 ml of benzanthrone solution (internal standard: about 100 mg of benzanthrone dissolved in toluene to a constant volume of 100 ml) in a 10 ml volumetric flask.
(8) Dissolve (6) with toluene, put into the volumetric flask of (7), and make a constant volume with toluene.
(9) Perform GC measurement under the following measurement conditions.

Apparatus: HP-5890 + HP-Chemical station Column: HP-1 30 m × 0.32 mm × 0.25 μm (manufactured by HP)
Inlet: 250 ° C
Detector: 280 ° C
Oven: constant 250 ° C. Carrier gas: He
Head pressure: 80 kPa
[Structure and shape of aliphatic carboxylic acid silver salt]
The shape of the aliphatic carboxylic acid silver salt that can be used in the present invention is not particularly limited, and may be any of a needle shape, a rod shape, a plate shape, and a flake shape. In the present invention, flake-shaped aliphatic carboxylic acid silver salts and short needle-shaped or rectangular parallelepiped-shaped aliphatic carboxylic acid silver salts having a major axis / minor axis length ratio of 5 or less are preferably used.

  In the present specification, the scaly aliphatic carboxylic acid silver salt is defined as follows. The aliphatic carboxylate silver salt was observed with an electron microscope, the shape of the aliphatic carboxylate silver salt particle was approximated to a rectangular parallelepiped, and the sides of this rectangular parallelepiped were designated as a, b, and c from the shortest side (c is b The calculation may be performed using the shorter numerical values a and b, and x is obtained as follows.

x = b / a
In this way, x is obtained for about 200 particles, and when the average value x (average) is obtained, particles satisfying the relationship of x (average) ≧ 1.5 are defined as flakes. Preferably, 30 ≧ x (average) ≧ 1.5, more preferably 20 ≧ x (average) ≧ 2.0. Incidentally, the needle shape is 1 ≦ x (average) <1.5.

  In the flake shaped particle, a can be regarded as a thickness of a tabular particle having a main plane with b and c as sides. The average of a is preferably 0.01 μm or more and 0.23 μm, more preferably 0.1 μm or more and 0.20 μm or less. The average c / b is preferably 1 or more and 6 or less, more preferably 1.05 or more and 4 or less, still more preferably 1.1 or more and 3 or less, and particularly preferably 1.1 or more and 2 or less.

  The aliphatic carboxylic acid silver salt according to the present invention may be a crystal particle having a core / shell structure as disclosed in European Patent 1168069A1 and Japanese Patent Application Laid-Open No. 2002-23303. In the case of a core / shell structure, all or part of either the core part or the shell part is an organic silver salt other than the aliphatic carboxylate silver, for example, silver of an organic compound such as phthalic acid or benzimidazole. A salt may be used as a constituent of the crystal particles.

  In the aliphatic carboxylic acid silver salt according to the present invention, the average equivalent circle diameter is preferably 0.01 μm or more and 0.60 μm or less, and the average thickness is 0.005 μm or more and 0.07 μm or less. The average equivalent circle diameter is preferably 0.10 μm or more and 0.50 μm or less, and the average thickness is 0.01 μm or more and 0.05 μm or less.

  When the average equivalent circle diameter is 0.01 μm or less, the transparency is excellent, but the image storage stability is poor, and when the average particle diameter is 0.60 μm or more, devitrification is severe. When the average thickness is 0.005 μm or less, the surface area is large, and silver ions are rapidly supplied during development. In particular, the low density area is not used for silver images, and there is a large amount of silver ions remaining in the film. The image storage stability is significantly deteriorated. On the other hand, when the average thickness is 0.07 μm or more, the surface area is reduced and the image stability is improved, but the silver supply during development is slow, resulting in unevenness of the developed silver shape particularly in the high density portion. The maximum concentration tends to be low.

  The particle size distribution of the organic silver salt particles according to the present invention (for example, the particle size distribution determined as the equivalent circle diameter) is preferably monodisperse. The term “monodispersed” as used herein means that the coefficient of variation of the particle diameter determined by the following formula is 25% or less. Preferably it is 20% or less, More preferably, it is 15% or less.

Coefficient of variation of particle size% = (standard deviation of particle size / average value of particle size) × 100
In order to determine the average equivalent circle diameter, the dispersed aliphatic carboxylic acid silver salt is diluted and dispersed on a grid with a carbon support film, and a transmission electron microscope (for example, JEOL Ltd., 2000FX type) directly An image is taken at a magnification of 5000 times, the negative is captured as a digital image by a scanner, and 300 or more particle sizes (equivalent circle diameter) are measured using an appropriate image processing software, and an average particle size can be calculated. .

  The average thickness can be calculated by a method using a TEM (transmission electron microscope) as shown below.

  First, the photosensitive layer coated on the support is attached to an appropriate holder with an adhesive, and an ultrathin slice having a thickness of 0.1 to 0.2 μm is produced using a diamond knife in a direction perpendicular to the support surface. To do. The prepared ultra-thin slice 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 TEM). The 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, it is preferable to appropriately select a portion where the section is not torn or slack as the field of view to be observed.

  As the carbon film, it is preferable to use a film supported by an organic film such as a very thin collodion or form bar. More preferably, the carbon film is formed on a rock salt substrate and dissolved and removed. It is a carbon-only film obtained by removal by organic solvent and ion etching. The acceleration voltage of TEM is preferably 80 to 400 kV, particularly preferably 80 to 200 kV.

  In addition, for details of electron microscope observation techniques and sample preparation techniques, see “The Japan Electron Microscopy Society Kanto Branch / Medical and Biological Electron Microscopy” (Maruzen), “The Japan Electron Microscopy Society Kanto Branch / Electron Microscope Biological Samples” "Manufacturing method" (Maruzen) can be referred to respectively.

  A TEM image recorded on a suitable medium is preferably decomposed into at least 1024 pixels × 1024 pixels, preferably 2048 pixels × 2048 pixels or more, and image processing by a computer is performed. 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 prepared, and a portion corresponding to the aliphatic carboxylate silver is extracted by binarization processing.

  The thickness of the extracted aliphatic carboxylic acid silver salt particles is manually measured with an appropriate software of 300 or more, and an average value is obtained.

  The method for obtaining the aliphatic carboxylic acid silver salt particles having the above-mentioned shape is not particularly limited. For example, the mixed state at the time of forming the organic acid alkali metal salt soap or the mixed state at the time of adding silver nitrate to the soap. It is effective to keep it good, and to set the ratio of the organic acid to the soap and the ratio of the silver nitrate that reacts with the soap optimally.

  In the present invention, tabular aliphatic carboxylic acid silver salt particles (aliphatic carboxylic acid having an average equivalent circle diameter of 0.05 μm to 0.8 μm and an average thickness of 0.005 μm to 0.07 μm) The acid silver salt particles) are preferably pre-dispersed with a binder, a surfactant or the like, if necessary, and then dispersed and ground with a media disperser or a high-pressure homogenizer. As the preliminary dispersion method, for example, a general stirrer such as an anchor type or a propeller type, a high speed rotary centrifugal radiation type stirrer (dissolver), or a high speed rotary shear type stirrer (homomixer) can be used.

  Further, as the media disperser, for example, a rolling mill such as a ball mill, a planetary ball mill, a vibrating ball mill, a bead mill that is a medium agitation mill, an attritor, and other basket mills can be used, and as a high-pressure homogenizer Various types can be used, such as a type that collides with a wall, a plug, etc., a type in which liquids are collided with each other at high speed, and a type through which a thin orifice is passed.

  Ceramics used for the ceramic beads used when dispersing media include yttrium-stabilized zirconia and zirconia-reinforced alumina (ceramics containing these zirconia) because of the low generation of impurities due to friction with the beads and the dispersing machine during dispersion. Is abbreviated as zirconia in the following).

  In the apparatus used for dispersing the tabular aliphatic carboxylate silver salt particles according to the present invention, examples of the material of the member in contact with the aliphatic carboxylate silver salt particles include zirconia, alumina, silicon nitride, and boron nitride. It is preferable to use ceramics such as the above or diamond, and it is preferable to use zirconia. When the above dispersion is performed, the binder concentration is preferably added in an amount of 0.1 to 10% of the mass of the aliphatic silver carboxylate, and it is preferable that the liquid temperature does not exceed 45 ° C. from the preliminary dispersion through the main dispersion. As preferable operating conditions for this dispersion, for example, when a high-pressure homogenizer is used as the dispersing means, 29 to 100 MPa, and the number of operations is preferably 2 or more. Moreover, when using a media disperser as a dispersion | distribution means, a peripheral speed of 6-13 m / sec is mentioned as preferable conditions.

  In the present invention, it is preferable that the non-photosensitive aliphatic carboxylic acid silver salt particles are formed in the presence of a compound that functions as a crystal growth inhibitor or a dispersant. Moreover, it is preferable that the compound which functions as a crystal growth inhibitor or a dispersing agent is an organic compound having a hydroxyl group or a carboxyl group.

  In the present invention, the compound that functions as a crystal growth inhibitor or dispersant for the aliphatic carboxylate silver particles refers to a silver aliphatic carboxylate under the conditions in which the compound coexists in the production process of the aliphatic carboxylate particles. A compound having a function and an effect of reducing the particle size or monodispersing than when it is produced under conditions that do not coexist. Specific examples include monohydric alcohols having 10 or less carbon atoms, preferably secondary alcohols, tertiary alcohols, glycols such as ethylene glycol and propylene glycol, polyethers such as polyethylene glycol, and glycerin. A preferable addition amount is 10 to 200% by mass with respect to the aliphatic carboxylate silver.

  On the other hand, branched aliphatic carboxylic acids containing isomers such as isoheptanoic acid, isodecanoic acid, isotridecanoic acid, isomyristic acid, isopalmitic acid, isostearic acid, isoarachidic acid, isobehenic acid and isohexaconic acid are also preferred. In this case, a preferable side chain includes an alkyl group or alkenyl group having 4 or less carbon atoms. In addition, aliphatic unsaturated carboxylic acids such as palmitoleic acid, oleic acid, linoleic acid, linolenic acid, moloctic acid, eicosenoic acid, arachidonic acid, eicosapentaenoic acid, erucic acid, docosapentaenoic acid, docosahexaenoic acid, and ceracolonic acid It is done. A preferable addition amount is 0.5 to 10 mol% of the silver aliphatic carboxylate.

  Glycosides such as glucoside, galactoside and fructoside, trehalose type disaccharides such as trehalose and sucrose, polysaccharides such as glycogen, dextrin, dextran and alginic acid, cellosolves such as methyl cellosolve and ethyl cellosolve, sorbitan, sorbit, ethyl acetate and acetic acid Water-soluble organic solvents such as methyl and dimethylformamide, water-soluble polymers such as polyvinyl alcohol, polyacrylic acid, acrylic acid copolymer, maleic acid copolymer, carboxymethylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, polyvinylpyrrolidone and gelatin Are also preferred compounds. A preferable addition amount is 0.1 to 20% by mass with respect to the aliphatic carboxylate silver.

  Alcohols having 10 or less carbon atoms, preferably secondary alcohols such as isopropyl alcohol and tertiary alcohols such as t-butyl alcohol are used to increase the solubility of the alkali metal salt of aliphatic carboxylic acid in the particle production process. By reducing the viscosity and increasing the stirring efficiency, it is monodispersed and the particle size is reduced. Branched aliphatic carboxylic acids and aliphatic unsaturated carboxylic acids have higher steric hindrance than the main component linear aliphatic carboxylic acid silver when crystallization of the aliphatic carboxylic acid silver, and the disorder of the crystal lattice is large. Therefore, large crystals are not generated, and as a result, the particle size is reduced.

(Method and apparatus for producing organic silver salt)
In the present invention, in an apparatus for producing organic silver salt particles using a silver ion-containing solution and an organic acid alkali metal salt solution, the silver ion-containing solution preparation tank and the organic acid alkali metal salt solution preparation tank It is preferable to have a static mixing device in which each solution is metered through a metering device. Accordingly, it is possible to provide a production apparatus capable of producing organic silver salt particles having a monodispersed particle size distribution, little fogging, and excellent coating properties.

  Hereinafter, although the manufacturing method and apparatus which concern on this invention are demonstrated, it is not limited to embodiment described below.

  In the case of an agitator using a normal mixing kettle, the generated nuclei circulate and return, so that nuclei cannot be generated in a uniform state during the nucleation time. The addition liquid is controlled to a desired amount to the apparatus, and the generated nuclei are immediately discharged through the discharge pipe, thereby enabling nucleation in a steady state. Here, the static mixing device refers to mixing a plurality of reaction solutions without intentionally performing physical stirring by the stirring device during an initial period in which the plurality of solutions contact and mix with each other for the first time. Refers to the device to be used. Further, the desired amount to be added to the static mixing device is an amount at which mixing is performed in a turbulent state. Turbulent flow refers to turbulence in which each particle of fluid has a partial velocity in directions other than the main flow, and its size is constantly changed.

  A conceptual diagram of a static mixing apparatus according to the present invention is shown in FIG.

  One of the silver ion-containing solution and the organic acid alkali metal salt solution is prepared in the preparation tank for additive liquid 1, and the other is prepared in the preparation tank for additive liquid 2.

  The addition liquids 1 and 2 prepared in the respective preparation tanks 11 and 22 in FIG. 1 are quantitatively supplied to the static mixing device 17 by the pumps 14 and 16 to generate organic silver particles. In the present invention, the silver ion-containing solution and the organic acid alkali metal salt solution or suspension are mixed under the condition that the temperature in the static mixing apparatus is 35 ° C. or higher and 70 ° C. or lower. Preferably they are 40 degreeC or more and 65 degrees C or less. More preferably, it is 40 degreeC or more and 60 degrees C or less. This is because if the mixing temperature is too low, the reaction in the static mixing device is suppressed, and if the temperature is too high, the side reaction is promoted.

  On the other hand, in order to further stabilize the production of the organic silver salt particles of the present invention, the amount of liquid to be supplied is detected by the flow rate detector 13, and the detection result is fed back to the pump 14 for additive liquid 1 to control the supply flow rate. Similarly, the amount of liquid to be supplied is detected by the flow rate detector 15, and the detection result is fed back to the pump 16 for additive liquid 2 to control the supply flow rate. By controlling the flow rates of the two liquids used for the reaction, it is possible to maintain a constant reaction field and suppress side reactions. Specific examples of the flow rate detection means include a flow meter or pressure gauge provided between the quantitative supply device and the static mixer, and a mass detection means provided in the preparation tank. The suspension containing the generated particles after mixing can be continuously cooled by the heat exchanger 18 to suppress particle growth. Thereby, the particle growth by Ostwald ripening can be suppressed.

  In the present invention, the heat exchanger used for cooling is not particularly limited. For example, multi-tubular heat exchanger, heat pipe heat exchanger, double pipe heat exchanger, coil heat exchanger, cascade heat exchanger, plate heat exchanger, swirl plate heat exchanger, water A cold heat exchanger can be used.

  As for the inner diameter of the mixed discharge pipe after mixing by the static mixing apparatus, if the inner diameter of the pipe is smaller than 1 mm, the liquid feeding speed is low, mixing is not sufficient, and productivity is lowered. When the inner diameter of the tube exceeds 100 mm, it becomes difficult to perform uniform mixing.

  In the manufacturing apparatus according to the present invention, the mixing discharge pipe and the plurality of supply pipe axes intersect at one place, and the mixing discharge pipe and the supply pipe are connected so that the axes coincide at the intersection. In this case, the axis of the mixed discharge pipe and the axes of the plurality of supply pipes intersect at one place, and the axes coincide at the intersection point are the axes of all the pipes. Are not limited to a desirable mode in which the axes are gathered at one place and the axes coincide at one intersection, but include a mode in which there is an axis misalignment within 10% of the inner diameter of the thickest pipe among the pipes to be connected. Within this range, the effects of the present invention can be obtained.

  The silver amount of the organic silver salt particles at the time when the silver salt solution and the organic acid alkali metal salt solution or suspension are mixed to generate the organic silver salt nucleus greatly affects the monodispersity of the particles. Therefore, it is preferable that the amount of silver is 0.0001 mol / L to 0.01 mol / L or less when a silver nitrate solution and an organic acid alkali metal salt solution or suspension are mixed to generate an organic silver salt nucleus, The upper limit is particularly preferably 0.008 mol / L or less, and most preferably 0.005 mol / L or less.

  In the organic silver salt production apparatus according to the present invention, it is important that the pump used when the silver nitrate solution and the organic acid alkali metal salt are mixed to generate organic silver salt nuclei has no pulsating flow. When the pulsation of the pump is large, the degree of supersaturation in the portion where both the silver nitrate solution and the organic acid alkali metal salt are mixed fluctuates greatly periodically, resulting in non-uniform nuclei. This significantly impairs the monodispersity of the produced particles. For this reason, the pulsating flow of the pump to be used is preferably ± 2.0% or less of the average flow rate, more preferably 1.0% or less, and particularly preferably 0.5%.

  In the organic silver salt production apparatus according to the present invention, the flow rate is measured in units of 1 second, and the arithmetic average is taken as the average flow rate, and the instantaneous flow rate fluctuation value = (maximum value−minimum value) / average flow rate is Preferably it does not exceed 4%.

  In the production apparatus according to the present invention, the mixing in the reaction apparatus is not particularly limited, but it is preferably a substantially turbulent flow in the sense of preventing backflow or mixing more uniformly. Turbulence is defined by the range of Reynolds number (Re). Here, the Reynolds number is defined as Re = DUρ / η, where D is the typical length of the object in the flow in contact with the fluid, U is the velocity, ρ is the density, and η is the viscosity. The number of dimensions.

  In general, when Re <2100, laminar flow, 2300 <Re <3000 is referred to as a transition region, and Re> 3000 is referred to as turbulent flow. In the present invention, substantially turbulent flow means Re> 3000, preferably Re> 5000, and more preferably Re> 10000.

  In particular, the Reynolds number in the mixed discharge pipe is preferably 3,000 or more as described above from the viewpoints of monodispersity of the particle diameter of organic silver salt particles, fogging, and the like.

In addition, it is preferable from a viewpoint of generation | occurrence | production reduction of fogging that the silver ion index | exponent (pAg) in 25 degreeC of the liquid mixture discharged | emitted from the said mixed discharge pipe is 3.5-5.0. Here, the silver ion index is an amount defined by pAg = −log [Ag ⁺ ]. Here, [Ag ⁺ ] represents the silver ion concentration (mol · dm ⁻³ ) in the solution at a specific temperature.

  Using the organic silver salt production apparatus according to the present invention, organic silver salt particles having a sphere equivalent average diameter of organic silver salt particles of 0.1 μm to 0.6 μm have a variation coefficient of the sphere equivalent average diameter of 25% or less. It can be produced, and the occurrence of fog can be reduced when the organic silver salt particles according to the present invention are used in a silver salt photothermographic dry imaging material.

(Photosensitive silver halide grains)
The photosensitive silver halide grains according to the present invention (simply referred to simply as “silver halide grains” or “silver halide”) can inherently absorb light as an intrinsic property of silver halide crystals. Or when it absorbs visible light or infrared light by an artificial physicochemical method and absorbs light in any region within the light wavelength range from the ultraviolet light region to the infrared light region. This refers to silver halide crystal grains that have been processed and produced so that physicochemical changes can occur in the silver halide crystal or on the crystal surface.

  As the photosensitive silver halide grains according to the present invention, silver halide grains conventionally disclosed in many patent publications relating to silver salt photothermographic dry imaging materials can be used. Specific examples of silver halide grains that can be preferably used include, for example, the manufacturing method described in JP-A-2003-270755, chemical properties such as halogen composition, physical properties such as shape, etc. Silver halide grains produced in the same manner.

  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. Particularly preferred is silver halide or silver iodide.

  In the silver halide grains used in the present invention, it is preferable to appropriately reduce the grain size of the silver halide grains in order to prevent white turbidity after image formation and to obtain good image quality, and the average grain size is 0. As a value when particles less than 0.01 μm are excluded from measurement, it is preferably 0.030 μm or more and 0.055 μm or less.

  The proportion of photosensitive silver halide grains having a particle size of 0.01 μm or more and 0.05 μm or less to the total amount of photosensitive silver halide grains is preferably 50% by mass or more in terms of silver amount. .

  Examples of the shape of the silver halide grains include cubes, octahedrons, tetrahedron grains, tabular grains, spherical grains, rod-like grains, potato-like grains, etc. Among these, cubic, octahedral, 14 Planar and tabular silver halide grains are preferred.

  The photosensitive silver halide grain according to the present invention is 0.001 to 0.7 mol, preferably 0.03 to 0.5 mol, based on 1 mol of an aliphatic carboxylic acid silver salt that can function as a silver ion source. It is preferred to use.

[Heat conversion internal latent image type silver halide grains]
The photosensitive silver halide grain according to the present invention is a heat conversion internal latent image type (internal latent image type after heat development) halogen disclosed in Japanese Patent Application Laid-Open No. 2003-270755 and Japanese Patent Application No. 2003-337269. Silver halide grains, that is, silver halide grains whose surface sensitivity is lowered by conversion from a surface latent image type to an internal latent image type by heat development are preferred. In other words, in exposure before heat development, a latent image that can function as a catalyst for a development reaction (reduction reaction of silver ions by a silver ion reducing agent) is formed on the surface of the silver halide grains, In exposure, since many latent images are formed inside the surface of the silver halide grains, it is a silver halide grain in which latent image formation on the surface is suppressed. preferable.

  The heat-converted internal latent image type silver halide grain according to the present invention is, in the same manner as a normal surface latent image type silver halide grain, 0. 1 mol per mol of an aliphatic carboxylic acid silver salt that can function as a silver ion source. It is preferably used at 001 to 0.7 mol, preferably 0.03 to 0.5 mol.

[Silver halide grain dispersion technology]
In the production process of the silver salt photothermographic imaging material of the present invention, from the viewpoint of improving photographic performance and color tone, aggregation of silver halide grains is prevented, and silver halide grains are dispersed relatively uniformly. In particular, it is preferable that the developed silver can be controlled to a desired shape.

  In order to prevent the above-described aggregation, uniform dispersion, etc., the gelatin used in the present invention has modified the properties of the gelatin by chemically modifying the hydrophilic groups such as amino groups and carboxyl groups of the gelatin according to the conditions of use. Those are preferred.

  For example, examples of the hydrophobic modification of the amino group in the gelatin molecule include phenylcarbamoylation, phthalation, succination, acetylation, benzoylation, and nitrophenylation, but are not particularly limited thereto. Moreover, 95% or more of these substitution rates are preferable, More preferably, it is 99% or more. Moreover, the hydrophobic modification of the carboxyl group may be combined, and examples thereof include methyl esterification and amidation, but are not particularly limited thereto. The substitution rate of the carboxyl group is preferably 50 to 90%, more preferably 70 to 90%. Here, the hydrophobic group in the above-mentioned hydrophobization modification refers to a group that increases hydrophobicity by substituting the amino group and / or carboxyl group of gelatin.

  In addition, the silver halide grain emulsion according to the present invention is preferably prepared by using a polymer that dissolves in both water and an organic solvent as described below in place of gelatin or in combination with gelatin. . For example, it is particularly preferred when the silver halide grain emulsion is coated by being uniformly dispersed in an organic solvent system.

  Examples of the organic solvent include alcohol-based, ester-based, and ketone-based compounds. In particular, ketone organic solvents such as acetone, methyl ethyl ketone, and diethyl ketone are preferable.

  The polymer soluble in both water and organic solvent may be any of natural polymer, synthetic polymer and copolymer. For example, gelatins, rubbers and the like that have been modified so as to belong to the category of the present invention can be used. Alternatively, polymers belonging to the following classifications can be used by introducing functional groups suitable for the purpose of preventing aggregation and uniform dispersion.

  For example, the polymer according to the present invention includes poly (vinyl alcohol) s, hydroxyethyl celluloses, cellulose acetates, cellulose acetate butyrates, poly (vinyl pyrrolidone) s, casein, starch, poly (acrylic acid and acrylic acid) Esters), poly (methyl methacrylic acid and methacrylate esters), poly (vinyl chloride) s, poly (methacrylic acid) s, styrene-maleic anhydride copolymers, styrene-acrylonitrile copolymers, styrene- Butadiene copolymers, poly (vinyl acetal) s (eg, poly (vinyl formal) and poly (vinyl butyral)), poly (esters), poly (urethanes), phenoxy resins, poly (vinylidene chloride) s, Poly (epoxide), poly (car Sulfonates), poly (vinyl acetate), poly (olefins), cellulose esters, poly (amides), and the like.

  Several types of these polymers may be copolymers, but polymers obtained by copolymerizing monomers of acrylic acid, methacrylic acid and esters thereof are particularly preferable.

  The polymer according to the present invention may be a polymer that dissolves in both water and an organic solvent in the same state, but also includes those that can be dissolved or insolubilized in water or an organic solvent by controlling the pH or controlling the temperature. It is.

  For example, although a polymer having an acidic group such as a carboxyl group becomes hydrophilic in a dissociated state depending on the type, it becomes oleophilic and soluble in a solvent when the pH is lowered to a non-dissociated state. Conversely, a polymer having an amino group becomes lipophilic when the pH is raised, and becomes ionized and water-soluble when the pH is lowered.

  The nonionic active agent is well known for the phenomenon of cloud point, but it has a property that it becomes lipophilic with increasing temperature and becomes soluble in organic solvents, and is hydrophilic, that is, soluble in water when the temperature decreases. Is also included in the polymer. It is sufficient that micelles are formed and uniformly emulsified even if they are not completely dissolved.

  In the present invention, since various monomers are combined, it is not generally stated which monomer should be used and how much, but a desired polymer can be obtained by combining a hydrophilic monomer and a hydrophobic monomer in an appropriate ratio. Is easily understood.

  The polymer that dissolves in both the water and the organic solvent may have a solubility of at least 1% by mass (25 ° C.) with respect to water, though it may be adjusted by adjusting the conditions such as pH as described above, or may not be adjusted. And an organic solvent having a solubility of 5% by mass or more (25 ° C.) in methyl ethyl ketone is preferable.

  As the polymer that is soluble in both the water and the organic solvent according to the present invention, a so-called block polymer, graft polymer, comb polymer, and the like are more suitable than a linear polymer from the viewpoint of solubility. A comb type polymer is particularly preferable. The isoelectric point of the polymer is preferably pH 6 or less.

  In the production process of the silver salt photothermographic dry imaging material of the present invention, for the purpose of preventing aggregation and uniform dispersion of the above-mentioned silver halide grains, a surfactant, in particular a non-ion, is added to the silver halide grain dispersion. It is also preferable to contain a functional surfactant.

  For nonionic surfactants, see generally Griffin W. et al. C. [J. Soc. Cosm. Chem. , 1, 311 (1949)], the hydrophilic / lipophilic equilibrium defined by its “HLB” value reflecting the proportion of hydrophilic and lipophilic groups in the molecule is −18 to 18, preferably − It is selected from nonionic hydrophilic compounds that are 15-0.

  As the nonionic surfactant used in the photosensitive silver halide emulsion according to the present invention, an activator represented by the following general formula (NSA1) or general formula (NSA2) is preferable.

Formula (NSA1) HO- (EO) _a- (AO) _b- (EO) _c -H
General formula (NSA2) HO- (AO) _d- (EO) _e- (AO) _f- H
In the formula, EO represents an oxyethylene group, AO represents an oxyalkylene group having 3 or more carbon atoms, and a, b, c, d, e, and f represent a number of 1 or more.

  Both are called pluronic-type nonionic surfactants, and in the general formula (NSA1) or (NSA2), examples of the oxyalkylene group having 3 or more carbon atoms represented by AO include oxypropylene group, oxybutylene group, oxy Long chain alkylene groups and the like can be mentioned, and oxypropylene groups are most preferred.

  A, b and c each represent a number of 1 or more, and d, e and f each represent a number of 1 or more. a and c are each preferably 1 to 200, more preferably 10 to 100, and b is preferably 1 to 300, and more preferably 10 to 200. d and f are each preferably 1 to 100, more preferably 5 to 50, respectively, and e is preferably 1 to 100, more preferably 2 to 50.

  In the photosensitive silver halide emulsion of the present invention, a macrocyclic compound containing a hetero atom is used. The macrocyclic compound containing a heteroatom is a 9-membered or higher macrocyclic compound containing at least one of a nitrogen atom, an oxygen atom, a sulfur atom, and a selenium atom as a heteroatom. Furthermore, a 12-24 membered ring is preferable, and a 15-21 membered ring is still more preferable.

  Representative compounds are those known as crown ethers, these compounds are C.I. J. et al. Pederson, Journal of American Chemical Society Vol, 86 (2495), 7017-7036 (1967), G.P. W. Gokel, S.M. H, Korzenowski, “Macrocyclic polyethr synthesis”, Springer-Vergal, (1982), Oda, Shono, Tabushi, “Chemistry of Crown Ether”, Chemistry Dojin (1978), Tafushi, “Host-Guest” Kyoritsu Shuppan (1979), Sasaki Koga "Synthetic Organic Chemistry" Vol 45 (6), 571-582 (1987).

(Chemical sensitization)
The photosensitive silver halide grains according to the present invention can be subjected to chemical sensitization disclosed in many patent publications and the like related to silver salt photothermographic dry imaging materials. For example, compounds or gold ions that release chalcogens such as sulfur, selenium, tellurium, etc. by the methods described in JP-A-2003-270755, JP-A-2001-249428, and JP-A-2001-249426. By using a noble metal compound that releases a noble metal ion, a chemical sensitization center capable of capturing electrons or holes (holes) generated by photoexcitation of photosensitive silver halide grains or spectral sensitizing dyes on the grains ( Chemical sensitization nuclei). In particular, it is preferably chemically sensitized with an organic sensitizer containing a chalcogen atom.

  These organic sensitizers containing chalcogen atoms are preferably compounds having groups capable of adsorbing to silver halide and unstable chalcogen atom sites.

  As these organic sensitizers, JP-A-60-150046, JP-A-4-109240, JP-A-11-218874, JP-A-11-218875, JP-A-11-218876, JP-A-11-194447, etc. The disclosed organic sensitizers having various structures can be used. Among them, at least one compound having a structure in which a chalcogen atom is bonded to a carbon atom or a phosphorus atom by a double bond is used. Preferably there is. In particular, a thiourea derivative having a heterocyclic group and a triphenylphosphine sulfide derivative are preferred.

  When the surface of the photosensitive silver halide grain according to the present invention is chemically sensitized, it is preferable that the chemical sensitization effect substantially disappears after the thermal development process. Here, the chemical sensitization effect substantially disappears when the sensitivity of the imaging material obtained by the chemical sensitization technique is 1.1 when the chemical sensitization is not performed after the thermal development process. Say to decrease to less than double. In order to eliminate the chemical sensitization effect in the heat development process, an oxidant capable of destroying the chemical sensitization center (chemical sensitization nucleus) by an oxidation reaction at the time of heat development, for example, the above-mentioned halogen radical releasing compound, etc. It is necessary to contain an appropriate amount of the above in the emulsion layer and / or the non-photosensitive layer of the imaging material. The content of the oxidizing agent is preferably adjusted in consideration of the oxidizing power of the oxidizing agent, the reduction range of the chemical sensitization effect, and the like.

(Spectral sensitization)
The photosensitive silver halide grain according to the present invention is preferably subjected to spectral sensitization by adsorbing a spectral sensitizing dye. Regarding spectral sensitization techniques, cyanine dyes, merocyanine dyes, complex cyanine dyes, complex merocyanine dyes, holopolar cyanine dyes, styryl dyes, and hemicyanines disclosed in many patent publications related to silver salt photothermographic dry imaging materials. Techniques using dyes, oxonol dyes, hemioxonol dyes and the like as spectral sensitizing dyes can be used.

  Specific examples of spectral sensitization techniques that can be preferably used in the silver salt photothermographic dry imaging material of the present invention include, for example, general formula (1) and general formula described in JP-A No. 2004-309758. This is a technique based on the spectral sensitization technique in which at least one selected from the sensitizing dyes represented by (2) is used.

  The emulsion containing photosensitive silver halide grains and aliphatic carboxylic acid silver salt grains used in the silver salt photothermographic dry imaging material of the present invention is a dye having no spectral sensitizing action itself or a sensitizing dye. A substance that does not substantially absorb visible light and exhibits a supersensitization effect may be included in the emulsion, whereby the silver halide grains may be supersensitized.

  Useful sensitizing dyes, combinations of dyes exhibiting supersensitization, and substances exhibiting supersensitization are described in RD17643 (issued in December, 1978), page 23, Section J, or Japanese Patent Publication No. 9-25500, 43-4933, JP-A-59-19032, JP-A-59-192242, JP-A-5-341432, and the like. As supersensitizers, heteroaromatic mercapto compounds or mercapto derivatives are described. Compounds are preferred.

  In addition to the above supersensitizers, macrocycles having heteroatoms disclosed in JP-A-2001-330918 can also be used as supersensitizers.

  It is preferred that the surface of the photosensitive silver halide grain according to the present invention is spectrally sensitized by adsorbing a spectral sensitizing dye, and the spectral sensitizing effect is substantially lost after the thermal development process. . Here, the spectral sensitization effect substantially disappears when the sensitivity of the imaging material obtained by a sensitizing dye, supersensitizer, etc. is the sensitivity when spectral sensitization is not performed after the thermal development process. It means to decrease to 1.1 times or less.

  In order to eliminate the spectral sensitization effect in the thermal development process, use a spectral sensitizing dye that is easily detached from the silver halide grains by heat during thermal development or / and destroy the spectral sensitizing dye by an oxidation reaction. It is necessary to contain an appropriate amount of an oxidizing agent that can be formed, for example, the above-mentioned halogen radical releasing compound in the emulsion layer and / or the non-photosensitive layer of the imaging material. The content of the oxidizing agent is preferably adjusted in consideration of the oxidizing power of the oxidizing agent, the reduction range of the spectral sensitization effect, and the like.

(Silver ion reducing agent)
The reducing agent according to the present invention can reduce silver ions in the photosensitive layer and is also referred to as a developer. Examples of the reducing agent include compounds represented by the following general formula (RD).

  In the present invention, as a silver ion reducing agent, in particular, at least one of the reducing agents may be a compound represented by the following general formula (RD) alone or in combination with another reducing agent having a different chemical structure. preferable.

[Wherein, X ₁ represents a chalcogen atom or CHR ₁ , and R ₁ represents a hydrogen atom, a halogen atom, an alkyl group, an alkenyl group, an aryl group or a heterocyclic group. R ₂ represents an alkyl group and may be the same or different. R ₃ represents an optionally substituted alkyl group having 2 to 20 carbon atoms. R ₄ represents a substitutable group on the benzene ring, and m and n each represents an integer of 0 to 2. ]
At least one group of the hydroxyl group in particular R ₃ Among the compounds represented by general formula (RD), or a compound represents an alkyl group having a group capable of forming a hydroxyl group as a substituent by being deprotected It is more preferable to use a silver salt photothermographic dry imaging material having a high density and excellent light irradiation image storage stability.

R ₂ is an alkyl group. The alkyl group is preferably a substituted or unsubstituted one having 1 to 20 carbon atoms, specifically, methyl, ethyl, propyl, i-propyl, butyl, i-butyl, t-butyl, t-pentyl, t-octyl. , Cyclohexyl, cyclopentyl, 1-methylcyclohexyl, 1-methylcyclopropyl and the like.

Although the substituent of the alkyl group is not particularly limited, for example, aryl group, hydroxyl group, alkoxy group, aryloxy group, alkylthio group, arylthio group, acylamino group, sulfonamido group, sulfonyl group, phosphoryl group, acyl group, carbamoyl group , Ester groups, halogen atoms and the like. Or it may form a saturated ring with (R _{4) m} and (R _{4) n.} R ₂ is preferably a secondary or tertiary alkyl group, and preferably has 2 to 20 carbon atoms. A tertiary alkyl group is more preferred, t-butyl, t-amyl, t-pentyl and 1-methylcyclohexyl are most preferred, and t-butyl is most preferred.

R ₃ represents an alkyl group having 2 to 20 carbon atoms. R ₃ is preferably ethyl, propyl, i-propyl, t-butyl, cyclohexyl, 1-methylcyclohexyl, 2-hydroxyethyl, 3-hydroxypropyl and the like. These groups may further have a substituent, and the substituents mentioned in the above R ₁ can be used as the substituent.

R ₃ is preferably a hydroxyl group or an alkyl group having 2 to 20 carbon atoms having a group capable of forming a hydroxyl group by deprotection (hereinafter also referred to as a precursor group), preferably a hydroxyl group or a precursor group thereof. It is a C2-C20 alkyl group which has these. The alkyl group preferably has 2 to 10 carbon atoms, more preferably 2 to 5 carbon atoms. The group that can be deprotected to form a hydroxyl group is preferably a group that forms a hydroxyl group by deprotection by the action of an acid and / or heat.

  Specifically, ether groups (methoxy groups, tert-butoxy groups, allyloxy groups, benzyloxy groups, triphenylmethoxy groups, trimethylsilyloxy groups, etc.), hemiacetal groups (tetrahydropyranyloxy groups, etc.), ester groups (acetyl) Oxy group, benzoyloxy group, p-nitrobenzoyloxy group, formyloxy group, trifluoroacetyloxy group, pivaloyloxy group, etc.), carbonate group (ethoxycarbonyloxy group, phenoxycarbonyloxy group, tert-butyloxycarbonyloxy group, etc.) ), Sulfonate groups (p-toluenesulfonyloxy group, benzenesulfonyloxy group etc.), carbamoyloxy groups (phenylcarbamoyloxy group etc.), thiocarbonyloxy groups (benzylthiocarbonyloxy group etc.), Ester group, sulfenates group (2,4-dinitrobenzene sulfenyl group and the like).

R ₃ is most preferably a primary alkyl group having 2 to 5 carbon atoms having a hydroxyl group or a precursor group thereof, such as 2-hydroxyethyl or 3-hydroxypropyl. A most preferred combination of R ₂ and R ₃ is a first group in which R ₂ is a tertiary alkyl group (t-butyl, t-amyl, 1-methylcyclohexyl, etc.), and R ₃ has a hydroxyl group or a precursor group thereof. A secondary alkyl group (2-hydroxyethyl, 3-hydroxypropyl, etc.). A plurality of R ₂ and R ₃ may be the same or different. Specific examples of the compound represented by the general formula (RD1a) include compounds R-1 to R-12, R-15 to R-20, and R-58 described in columns 6 to 16 of US Pat. No. 6,800,431. ~ R-59.

R ₄ represents a hydrogen atom or a group that can be substituted on the benzene ring, and specifically, an alkyl group having 1 to 25 carbon atoms (methyl, ethyl, propyl, i-propyl, t-butyl, pentyl, hexyl, cyclohexyl). Etc.), halogenated alkyl groups (trifluoromethyl, perfluorooctyl etc.), cycloalkyl groups (cyclohexyl, cyclopentyl etc.), alkynyl groups (propargyl etc.), glycidyl groups, acrylate groups, methacrylate groups, aryl groups (phenyl etc.) , Heterocyclic groups (pyridyl, thiazolyl, oxazolyl, imidazolyl, furyl, pyrrolyl, pyrazinyl, pyrimidinyl, pyridazinyl, selenazolyl, sriphoranyl, piperidinyl, pyrazolyl, tetrazolyl, etc.), halogen atoms (chlorine, bromine, iodine, fluorine), alkoxy groups ( Methoxy Ethoxy, propyloxy, pentyloxy, cyclopentyloxy, hexyloxy, cyclohexyloxy, etc.), aryloxy groups (phenoxy, etc.), alkoxycarbonyl groups (methyloxycarbonyl, ethyloxycarbonyl, butyloxycarbonyl, etc.), aryloxycarbonyl groups ( Phenyloxycarbonyl, etc.), sulfonamide groups (methanesulfonamide, ethanesulfonamide, butanesulfonamide, hexanesulfonamide group, cyclohexanesulfonamide, benzenesulfonamide, etc.), sulfamoyl groups (aminosulfonyl, methylaminosulfonyl, dimethylaminosulfonyl) , Butylaminosulfonyl, hexylaminosulfonyl, cyclohexylaminosulfonyl, phenylaminosulfonyl, 2-pi Lysylaminosulfonyl, etc.), urethane groups (methylureido, ethylureido, pentylureido, cyclohexylureido, phenylureido, 2-pyridylureido, etc.), acyl groups (acetyl, propionyl, butanoyl, hexanoyl, cyclohexanoyl, benzoyl, pyridinoyl, etc.) ), Carbamoyl group (aminocarbonyl, methylaminocarbonyl, dimethylaminocarbonyl, propylaminocarbonyl, pentylaminocarbonyl group, cyclohexylaminocarbonyl, phenylaminocarbonyl, 2-pyridylaminocarbonyl), amide group (acetamide, propionamide, butanamide, hexane Amide, benzamide, etc.), sulfonyl group (methylsulfonyl, ethylsulfonyl, butylsulfonyl, cyclohexyl) Sulfonyl, phenylsulfonyl, 2-pyridylsulfonyl, etc.), amino group (amino, ethylamino, dimethylamino, butylamino, cyclopentylamino, anilino, 2-pyridylamino, etc.), cyano group, nitro group, sulfo group, carboxyl group, hydroxyl group Group, oxamoyl group and the like. These groups may be further substituted with these groups. m and n represent an integer of 0 to 2, and most preferably m and n are both 0.

R ₄ may form a saturated ring with R ₂ and R ₃ . R ₄ is preferably a hydrogen atom, a halogen atom or an alkyl group, more preferably a hydrogen atom. A plurality of R ₄ may be the same or different.

  Although the specific example of a compound represented by general formula (RD) below is given, this invention is not limited to these.

  These bisphenol compounds represented by the general formula (RD) can be easily synthesized by a conventionally known method.

  In the present invention, examples of the reducing agent that can be used in combination include US Pat. Nos. 3,770,448, 3,773,512, and 3,593,863, RD17029 and 29963. And reducing agents described in JP-A-11-119372 and JP-A-2002-62616.

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

(Image tone)
Next, the color tone of an image obtained by thermally developing a silver salt photothermographic dry imaging material will be described.

  Regarding the color tone of an output image for medical diagnosis such as a conventional X-ray photographic film, it is said that a cold tone image tone is easier for a reader to obtain a more accurate diagnostic observation result. Here, the cool image tone means a pure black tone or a bluish black tone of a black image. On the other hand, the warm image tone is said to be a warm black tone with a black image, but in order to allow a more precise quantitative discussion, the International Lighting Commission (CIE) ), Based on the recommended expression.

The terms “more cold” and “more warm” regarding the color tone can be expressed by the hue angle hab at the minimum density Dmin and the optical density D = 1.0. That is, the hue angle hab is expressed by the color coordinates a ^* and b ^* of the color space L ^* a ^* b ^* color space, which is a color space having a perceptually uniform rate recommended by the International Commission on Illumination (CIE) in 1976. Using the following formula.

hab = tan ⁻¹ (b ^* / a ^* )
As a result of examination by the expression method based on the hue angle, the hue of the photothermographic dry imaging material of the present invention after development is preferably such that the range of the hue angle hab is 180 degrees <hab <270 degrees, more preferably 200 degrees. It has been found that degrees <hab <270 degrees, most preferably 220 degrees <hab <260 degrees. This is disclosed in Japanese Patent Laid-Open No. 2002-6463.

Conventionally, the CIE 1976 (L ^* u ^* v ^* ) color space or the (L ^* a ^* b ^* ) color space near the optical density of 1.0 is specified as u ^* , v ^* or a ^* , b ^* . It is known that a diagnostic image with a favorable color tone can be obtained by adjusting to a numerical value, and is described in, for example, Japanese Patent Application Laid-Open No. 2000-29164.

However, as disclosed in Japanese Patent Application Laid-Open No. 2004-94240, the silver salt photothermographic dry imaging material of the present invention has a CIE 1976 (L ^* u ^* v ^* ) color space or (L ^* a ^* b ^*). ) In a color space, plotting u ^* , v ^* or a ^* , b ^* at various photographic densities on a graph with the horizontal axis u ^* or a ^* and the vertical axis v ^* or b ^*, and linear regression It has been found that, when a straight line is created, by adjusting the linear regression line to a specific range, it is possible to have a diagnostic property equal to or higher than that of a conventional wet silver salt photosensitive material. Preferred specific condition ranges are described below.

(1) The silver salt photothermographic dry imaging material was measured for each of the optical densities of 0.5, 1.0, 1.5 and the lowest optical density of the silver image obtained after the heat development processing, and CIE 1976 (L ^* u ^* v ^* ) The coefficient of determination of the linear regression line created by arranging u ^* and v ^* at the above optical densities in two-dimensional coordinates where the horizontal axis of the color space is u ^* and the vertical axis is v ^*. Determination) R ² is preferably 0.998 to 1.000. Furthermore, it is preferable that the v ^* value of the intersection with the vertical axis of the linear regression line is −5 to 5 and the slope (v ^* / u ^* ) is 0.7 to 2.5.

(2) In addition, the optical density of the photothermographic dry imaging material is measured at 0.5, 1.0, 1.5 and the lowest optical density, next to the CIE 1976 (L ^* a ^* b ^* ) color space. The coefficient of determination (multiple determination) R ^{2 of} the linear regression line created by arranging a ^* and b ^* at each optical density in the two-dimensional coordinates where the axis is a ^* and the vertical axis is b ^* is from 0.998 to It is preferable that it is 1.000. Furthermore, it is preferable that the b ^* value of the intersection with the vertical axis of the linear regression line is −5 to 5 and the slope (b ^* / a ^* ) is 0.7 to 2.5.

Next, an example of a method for creating the above-described linear regression line, that is, a method for measuring u ^* , v ^* and a ^* , b ^{* in} the CIE1976 color space will be described.

A four-stage wedge sample including an unexposed portion and optical densities of 0.5, 1.0, and 1.5 is prepared using a heat development apparatus. Each wedge density part thus produced is measured with a spectrocolorimeter (Minolta Co., Ltd .: CM-3600d or the like), and u ^* , v ^* or a ^* , b ^* are calculated. The measurement conditions at that time are F7 light source as the light source, the viewing angle is 10 degrees, and the measurement is performed in the transmission measurement mode. Plot u ^* , v ^* or a ^* , b ^* measured on a graph with u ^* or a ^{* on} the horizontal axis and v ^* or b ^{* on the} vertical axis to obtain a linear regression line, and the coefficient of determination (multiple determination) Find R ² , intercept and slope.

  Next, a specific method for obtaining a linear regression line having the above characteristics will be described.

  In the present invention, adjustment of the addition amount of a compound or the like directly or indirectly involved in the development reaction process of a reducing agent (developer), silver halide grains, aliphatic silver carboxylate and the following toning agent, etc. Thus, the developed silver shape can be optimized to obtain a preferable color tone. For example, when the developed silver shape is dendritic, it becomes a bluish direction, and when it is a filament shape, it becomes a yellowish direction. That is, it can be adjusted in consideration of the tendency of the developed silver shape.

  Conventionally, phthalazinone or phthalazine and phthalic acids and phthalic anhydrides are generally used as toning agents. Examples of suitable toning agents include RD17029, U.S. Pat. Nos. 4,123,282, 3,994,732, 3,846,136, and 4,021,249. Is disclosed.

  In addition to such toning agents, color tone using couplers disclosed in JP-A-11-288057, European Patent No. 1,134,611A2, etc. and leuco dyes described in detail below. Can also be adjusted. In particular, a coupler or leuco dye is preferably used for fine adjustment of the color tone.

(Leuco dye)
As described above, the silver salt photothermographic dry imaging material of the present invention can also be adjusted in color tone using a leuco dye. The leuco dye is preferably any colorless or slightly colored compound that is oxidized to a colored form when heated at a temperature of about 80-200 ° C. for about 0.5-30 seconds. Any leuco dye that can be oxidized by the body to form a pigment can be used. Compounds that are pH sensitive and can be oxidized to a colored state are useful.

  Representative leuco dyes suitable for use in the present invention are not particularly limited. For example, biphenol leuco dyes, phenol leuco dyes, indoaniline leuco dyes, acrylated azine leuco dyes, phenoxazine leuco dyes, phenodiazine leuco dyes. And phenothiazine leuco dye. Also useful are US Pat. Nos. 3,445,234, 3,846,136, 3,994,732, 4,021,249, 4,021,250, 4,022,617, 4,123,282, 4,368,247, 4,461,681, and JP-A-50-36110, 59-26831, These are leuco dyes disclosed in JP-A-5-204087, JP-A-11-231460, JP-A-2002-169249, and JP-A-2002-236334.

  In order to adjust to a predetermined color tone, it is preferable to use leuco dyes of various colors singly or in combination of a plurality of types. In addition, the use of highly active reducing agents for rapid processing changes the color tone (especially yellowishness) depending on the amount and ratio of use, or uses fine silver halide grains to develop developed silver. In order to prevent the image from becoming excessively reddish, especially in the high density part where the density is 2.0 or more, the use of a leuco dye that develops yellow and cyan colors is used in combination. It is preferable to adjust the amount.

  The color density is preferably adjusted appropriately in relation to the color tone of the developed silver itself. In the present invention, the color tone is adjusted so as to have an image in the above preferable color tone range by developing the color so as to have a reflection optical density of 0.01 to 0.05 or a transmission optical density of 0.005 to 0.50. preferable. In the present invention, the sum of the maximum densities at the maximum absorption wavelength of the dye image formed by the leuco dye is preferably 0.01 or more and 0.50 or less, more preferably 0.02 or more and 0.30 or less, and particularly preferably It is preferable that the color is developed so as to have 0.03 or more and 0.10 or less.

(Yellow coloring leuco dye)
As described above, the silver salt photothermographic dry imaging material of the present invention preferably adjusts the color tone using a leuco dye. In the present invention, a color image forming agent whose absorbance at 360 to 450 nm is increased by oxidation is particularly preferably used as a yellow color-forming leuco dye. These color image forming agents are particularly preferably color image forming agents represented by the following general formula (YA).

[Wherein R ₁₁ represents a substituted or unsubstituted alkyl group, R ₁₂ represents a hydrogen atom, a substituted or unsubstituted alkyl group or an acylamino group, and R ₁₁ and R ₁₂ represent a 2-hydroxyphenylmethyl group. There is never. R ₁₃ represents a hydrogen atom or a substituted or unsubstituted alkyl group, and R ₁₄ represents a substituent that can be substituted on the benzene ring. ]
Hereinafter, the compound of the general formula (YA) will be described in detail.

In General Formula (YA), R ₁₁ represents a substituted or unsubstituted alkyl group. When R ₁₂ is a substituent other than a hydrogen atom, R ₁₁ represents an alkyl group. The alkyl group is preferably an alkyl group having 1 to 30 carbon atoms and may have a substituent.

Specifically, methyl, ethyl, butyl, octyl, i-propyl, t-butyl, t-octyl, t-pentyl, sec-butyl, cyclohexyl, 1-methyl-cyclohexyl and the like are preferable, and steric rather than i-propyl. Are preferably large groups (i-propyl, i-nonyl, t-butyl, t-amyl, t-octyl, cyclohexyl, 1-methyl-cyclohexyl, adamantyl, etc.), among which secondary or tertiary alkyl Group is preferable, and tertiary alkyl groups such as t-butyl, t-octyl, and t-pentyl are particularly preferable. Examples of the substituent that R ₁₁ may have include a halogen atom, an aryl group, an alkoxy group, an amino group, an acyl group, an acylamino group, an alkylthio group, an arylthio group, a sulfonamido group, an acyloxy group, an oxycarbonyl group, and a carbamoyl group. , Sulfamoyl group, sulfonyl group, phosphoryl group and the like.

R ₁₂ represents a hydrogen atom, a substituted or unsubstituted alkyl group or an acylamino group. The alkyl group represented by R ₁₂ is preferably an alkyl group having 1 to 30 carbon atoms, and the acylamino group is preferably an acylamino group having 1 to 30 carbon atoms. Among these, the description of the alkyl group is the same as R ₁₁ described above.

The acylamino group represented by R ₁₂ may be unsubstituted or substituted, and specific examples include an acetylamino group, an alkoxyacetylamino group, and an aryloxyacetylamino group. R ₁₂ is preferably a hydrogen atom or an unsubstituted alkyl group having 1 to 24 carbon atoms, and specific examples include methyl, i-propyl, and t-butyl. R ₁₁ and R ₁₂ are not 2-hydroxyphenylmethyl groups.

R ₁₃ represents a hydrogen atom or a substituted or unsubstituted alkyl group. The alkyl group is preferably an alkyl group having 1 to 30 carbon atoms, and the description of the alkyl group is the same as that for R ₁₁ . R ₁₃ is preferably a hydrogen atom or an unsubstituted alkyl group having 1 to 24 carbon atoms, and specific examples include methyl, i-propyl, t-butyl and the like. Further, it is preferable either R _12, R ₁₃ is a hydrogen atom.

R ₁₄ represents a group substitutable on the benzene ring, and is, for example, the same group as described for the substituent R ₄ in the general formula (RD). R ₁₄ is preferably a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms or an oxycarbonyl group having 2 to 30 carbon atoms, and more preferably an alkyl group having 1 to 24 carbon atoms. Examples of the substituent of the alkyl group include an aryl group, an amino group, an alkoxy group, an oxycarbonyl group, an acylamino group, an acyloxy group, an imide group, and a ureido group, and more preferable examples include an aryl group, an amino group, an oxycarbonyl group, and an alkoxy group. preferable. These alkyl group substituents may be further substituted with these substituents.

  Next, among the compounds represented by the general formula (YA), the bisphenol compound represented by the following general formula (YB), which is particularly preferably used in the present invention, will be described.

[Wherein, Z represents —S— or —C (R ₂₁ ) (R ₂₁ ′) —, and R ₂₁ and R ₂₁ ′ each represents a hydrogen atom or a substituent. ]
Examples of the substituent represented by R ₂₁ and R ₂₁ ′ include the same groups as the substituents exemplified in the description of R _{1 in} the general formula (RD). R ₂₁ and R ₂₁ ′ are preferably a hydrogen atom or an alkyl group.

R ₂₂ , R ₂₃ , R ₂₂ ′ and R ₂₃ ′ each represent a substituent, and examples of the substituent include the same groups as those described for R ₂ and R ₃ in the general formula (RD).

R ₂₂ , R ₂₃ , R ₂₂ ′ and R ₂₃ ′ are preferably an alkyl group, an alkenyl group, an alkynyl group, an aryl group or a heterocyclic group, but an alkyl group is more preferable. Examples of the substituent on the alkyl group include the same groups as those described in the description of the substituent in the general formula (RD).

R ₂₂ , R ₂₃ , R ₂₂ ′ and R ₂₃ ′ are more preferably tertiary alkyl groups such as t-butyl, t-pentyl, t-octyl and 1-methyl-cyclohexyl.

R ₂₄ and R ₂₄ ′ each represent a hydrogen atom or a substituent, and examples of the substituent include the same groups as those described in the description of R ₄ in the general formula (RD).

  Examples of the compounds represented by the general formulas (YA) and (YB) include compounds (II-1) to (II-40) described in paragraphs “0032” to “0038” of JP-A No. 2002-169249, Examples thereof include compounds (ITS-1) to (ITS-12) described in paragraph “0026” of EP 1,211,093.

  Although the specific example of the bisphenol compound represented by general formula (YA) and (YB) below is shown, this invention is not limited to these.

  The addition amount of the compound of the general formula (YA) (including hindered phenol compounds and compounds of the general formula (YB)) is usually 0.00001 to 0.01 mol, preferably 0. 0005 to 0.01 mol, more preferably 0.001 to 0.008 mol.

  Moreover, it is preferable that the addition amount ratio with respect to the sum total of the reducing agent represented by general formula (RD) of yellow coloring leuco dye is 0.001-0.2 by molar ratio, 0.005-0.1 It is more preferable that

(Cyan coloring leuco dye)
The silver salt photothermographic dry imaging material of the present invention preferably adjusts the color tone by using a cyan coloring leuco dye in addition to the yellow coloring leuco dye.

  The cyan chromophoric leuco dye is preferably any colorless or slightly colored compound that is oxidized to a colored form when heated at a temperature of about 80-200 ° C. for about 0.5-30 seconds. Any leuco dye that forms a pigment by oxidation with an oxidant of the agent can be used. Compounds that are pH sensitive and can be oxidized to a colored state are useful.

In the present invention, a color image forming agent whose absorbance at 600 to 700 nm is increased by oxidation is particularly preferably used as a cyan color-forming leuco dye. Examples of these compounds include compounds of general formula (I) to general formula (IV) described in JP-A-59-206831 (particularly compounds having λmax in the range of 600 to 700 nm) and JP-A-5-204087. Specifically, the compounds of (1) to (18) described in paragraphs “0032” to “0037”) and compounds of general formulas 4 to 7 in JP-A No. 11-231460 (specifically, paragraph “0105”). No. 1 to No. 79 compounds).
The cyan color-forming leuco dye preferably used in the present invention is a compound represented by the following general formula (CLA) or general formula (CLB). The color image forming agent represented by the general formula (CLB) is particularly preferable in that it has high color development efficiency, can be adjusted in color even when added in a small amount, and is excellent in image storage stability.
The compounds of general formula (CLA) and general formula (CLB) that are preferably used below will be described in detail.

  (Compound represented by general formula (CLA))

[Wherein R ₃₁ and R ₃₂ are a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, alkenyl group, alkoxy group, —NHCO—R ₃₀ group (R ₃₀ is an alkyl group, aryl group, heterocyclic group) Or R ₃₁ and R ₃₂ are groups that are linked to each other to form an aliphatic hydrocarbon ring, an aromatic hydrocarbon ring, or a heterocyclic ring.

The —A ₃ —R ₃₃ moiety represents a hydrogen atom, or A ₃ represents a —NHCO— group, —CONH— group or —NHCONH— group, and R ₃₃ represents a substituted or unsubstituted alkyl group, aryl Represents a group or a heterocyclic group.

W ₃ represents a hydrogen atom or —CONH—R ₃₅ group, —CO—R ₃₅ group or —CO—O—R ₃₅ group (R ₃₅ represents a substituted or unsubstituted alkyl group, aryl group or heterocyclic group). R ₃₄ represents a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, alkenyl group, alkoxy group, carbamoyl group, or nitrile group. R ₃₆ represents —CONH—R ₃₇ group, —CO—R ₃₇ group or —CO—O—R ₃₇ group (R ₃₇ represents a substituted or unsubstituted alkyl group, aryl group or heterocyclic group) X ₃ Represents a substituted or unsubstituted aryl group or heterocyclic group. ]
In the general formula (CLA), examples of the halogen atom represented by R ₃₁ and R ₃₂ include a fluorine atom, a bromine atom, and a chlorine atom, and the alkyl group includes an alkyl group having up to 20 carbon atoms (for example, Methyl group, ethyl group, butyl group, dodecyl group, etc.). Examples of the alkenyl group include alkenyl groups having up to 20 carbon atoms (for example, vinyl group, allyl group, butenyl group, hexenyl group, hexadienyl group, ethenyl-2-ethyl group). A propenyl group, a 3-butenyl group, a 1-methyl-3-propenyl group, a 3-pentenyl group, a 1-methyl-3-butenyl group, and the like. As the alkoxy group, an alkoxy group having up to 20 carbon atoms (for example, methoxy) Group, ethoxy and the like). Examples of the alkyl group represented by R ₃₀ in the —NHCO—R ₃₀ group include alkyl groups having up to 20 carbon atoms (for example, a methyl group, an ethyl group, a butyl group, a dodecyl group, etc.), and an aryl group. Examples thereof include a group having 6 to 20 carbon atoms such as a phenyl group and a naphthyl group, and examples of the heterocyclic group include a thiophene group, a furan group, an imidazole group, a pyrazole group, and a pyrrole group. The alkyl group represented by R ₃₃ is preferably an alkyl group having up to 20 carbon atoms, and examples thereof include a methyl group, an ethyl group, a butyl group, and a dodecyl group, and the aryl group preferably has 6 to 20 carbon atoms. Examples of the aryl group include a phenyl group and a naphthyl group. Examples of the heterocyclic group include a thiophene group, a furan group, an imidazole group, a pyrazole group, and a pyrrole group.

In the —CONH—R ₃₅ group, —CO—R ₃₅ group or —CO—O—R ₃₅ group represented by W ₃ , the alkyl group represented by R ₃₅ is preferably an alkyl group having up to 20 carbon atoms. Examples thereof include a methyl group, an ethyl group, a butyl group, and a dodecyl group. The aryl group is preferably an aryl group having 6 to 20 carbon atoms, and examples thereof include a phenyl group and a naphthyl group. Examples of the heterocyclic group include a thiophene group, a furan group, an imidazole group, a pyrazole group, and a pyrrole group.

Examples of the halogen atom represented by R ₃₄ include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. Examples of the alkyl group include a chain or cyclic alkyl group such as a methyl group, a butyl group, and dodecyl. Group, cyclohexyl group and the like. Examples of the alkenyl group include alkenyl groups having up to 20 carbon atoms (for example, vinyl group, allyl group, butenyl group, hexenyl group, hexadienyl group, ethenyl-2-propenyl group, 3-butenyl group, 1-methyl-3-propenyl group, 3-pentenyl group, 1-methyl-3-butenyl, etc.), and alkoxy groups include, for example, methoxy group, butoxy group, tetradecyloxy group, etc., and carbamoyl Examples of the group include a diethylcarbamoyl group and a phenylcarbamoyl group. Nitrile groups are also preferred. Among these, a hydrogen atom and an alkyl group are more preferable. R ₃₃ and R ₃₄ may be connected to each other to form a ring structure.

  The above groups can further have a single substituent or multiple substituents. Typical substituents include halogen atoms (eg, fluorine atom, chlorine atom, bromine atom), alkyl groups (eg, methyl group, ethyl group, propyl group, butyl group, dodecyl group), hydroxyl group, cyano group , Nitro group, alkoxy group (for example, methoxy group, ethoxy group, etc.), alkylsulfonamide group (for example, methylsulfonamide group, octylsulfonamide group, etc.), arylsulfonamide group (for example, phenylsulfonamide group, naphthylsulfone) Amide group etc.), alkylsulfamoyl group (eg butylsulfamoyl group etc.), arylsulfamoyl (eg phenylsulfamoyl group etc.), alkyloxycarbonyl group (eg methoxycarbonyl group etc.), aryl Oxycarbonyl group (for example, phenyloxycarbonyl group, etc.) , Amino sulfonamido group, an acylamino group, a carbamoyl group, a sulfonyl group, a sulfinyl group, a sulfoxy group, a sulfo group, an aryloxy group, an alkoxy group, an alkylcarbonyl group, arylcarbonyl group, and an amino carbonyl group.

R ₃₀ or R ₃₅ is preferably a phenyl group, and more preferably a phenyl group having a plurality of halogen atoms and cyano groups as substituents.

-CONH-R ₃₇ group represented by R _36, in -CO-R ₃₇ group, or -CO-O-R ₃₇ group, the alkyl group represented by R ₃₇ is preferably an alkyl group having up to 20 carbon atoms Yes, for example, a methyl group, an ethyl group, a butyl group, a dodecyl group, and the like. The aryl group is preferably an aryl group having 6 to 20 carbon atoms, and examples thereof include a phenyl group, a naphthyl group, and a thienyl group. Examples of the heterocyclic group include a thiophene group, a furan group, an imidazole group, a pyrazole group, and a pyrrole group.

As the substituent that the group represented by R ₃₇ can have, the same substituents as those described in the description of R _{31 to} R _{34 in} formula (CLA) can be used.

Examples of the aryl group represented by X ₃ include aryl groups having 6 to 20 carbon atoms such as a phenyl group, a naphthyl group, and a thienyl group. Examples of the heterocyclic group include a thiophene group, a furan group, and an imidazole group. Group, pyrazole group, pyrrole group and the like.

Examples of the substituent that the group represented by X ₃ can have include the same substituents as those described in the description of R _{31 to} R _{34 in} formula (CLA).
The group represented by X ₃ is preferably an aryl group or heterocyclic group having an alkylamino group (such as a diethylamino group) at the para position.

  These groups may include photographically useful groups.

  Specific examples of the cyan color forming leuco dye (CLA) are shown below, but the cyan color forming leuco dye used in the present invention is not limited thereto.

(Compound represented by general formula (CLB))
Next, the compound (leuco dye) represented by the general formula (CLB-1) will be described in detail.

In the general formula (CLB-I), R ₁₁ , R ₁₂ , Ra and Rb are each a hydrogen atom, aliphatic group, aromatic group, alkoxy group, aryloxy group, acylamino group, sulfonamide group, carbamoyl group or halogen. Represents an atom. R ₁₃ represents a hydrogen atom, aliphatic group, aromatic group, acyl group, alkoxycarbonyl group, aryloxycarboquinyl group, carbamoyl group, sulfamoyl group or sulfonyl group. X ₁ and X ₂ each represent a substitutable group on the benzene ring, and m 1 and m 2 each represent an integer of 0 to 5. When there are a plurality of X ₁ or X ₂ , each X ₁ and X ₂ may be the same or different.

Specific examples of the aliphatic group represented by R ₁₁ , R ₁₂ , Ra and Rb include hydrocarbon groups such as an alkyl group, an alkenyl group and an alkynyl group. These hydrocarbon groups preferably have 1 to 25 carbon atoms, and more preferably 1 to 20 carbon atoms. Examples of the alkyl group having 1 to 25 carbon atoms include methyl, ethyl, propyl, i-propyl, t-butyl, pentyl, hexyl, cyclohexyl, etc., cycloalkyl groups (cyclohexyl, cyclopentyl groups, etc.), and alkenyl groups, ethenyl. -2-propenyl, 3-butenyl, 1-methyl-3-propenyl, 3-pentenyl, 1-methyl-3-butenyl and the like) and alkynyl groups (ethynyl, 1propynyl, propargyl and the like).

Specific examples of the aromatic group represented by R ₁₁ , R ₁₂ , Ra and Rb include aryl groups (phenyl, naphthyl, etc.), heterocyclic groups (pyridyl, thiazolyl, oxazolyl, imidazolyl, furyl, pyrrolyl, pyrazinyl, pyrimidinyl , Pyridazinyl, selenazolyl, sriphoranyl, piperidinyl, pyrazolyl, tetrazolyl and the like.

Specific examples of the alkoxy group represented by R ₁₁ , R ₁₂ , Ra and Rb include methoxy, ethoxy, i-propoxy, t-butoxy and the like. Specific examples of the aryloxy group include phenoxy and naphthyloxy. Examples of the acylamino group include acetylamino and benzoylamino. Specific examples of the sulfonamide group include methanesulfonamide, butanesulfonamide, octanesulfonamide, and benzenesulfonamide. Examples of the carbamoyl group include aminocarbonyl, methylaminocarbonyl, dimethylaminocarbonyl, propylaminocarbonyl, pentylaminocarbonyl, cyclohexylaminocarbonyl, phenylaminocarbonyl, 2-pyridylaminocarbonyl and the like. The halogen atoms represented by R ₁₁ , R ₁₂ , Ra and Rb are chlorine, bromine and iodine.

R ₁₁ and R ₁₂ are preferably an aliphatic group, an alkoxy group, an aryloxy group, more preferably an alkyl group or an alkoxy group, still more preferably a secondary or tertiary alkyl group or an alkoxy group. Ra and Rb are preferably a hydrogen atom or an aliphatic group, more preferably a hydrogen atom.

Examples of the aliphatic group, aromatic group, alkoxy group and aryloxy group represented by R ₁₃ are the aliphatic group represented by R ₁₁ , R ₁₂ , Ra and Rb in the general formula (CLB-I), aromatic Specific examples of the group, the alkoxy group, and the aryloxy group are listed.

Specific examples of the acyl group represented by R ₁₃ include groups such as acetyl, propionyl, butanoyl, hexanoyl, cyclohexanoyl, benzoyl and pyridinoyl. Specific examples of the alkoxycarbonyl group include methoxycarbonyl, ethoxycarbonyl, t-butoxycarbonyl and the like. Specific examples of the aryloxycarboquinyl group include phenoxycarbonyl and the like. Examples of the carbamoyl group include aminocarbonyl, methylaminocarbonyl, dimethylaminocarbonyl, propylaminocarbonyl, pentylaminocarbonyl, cyclohexylaminocarbonyl, phenylaminocarbonyl, 2-pyridylaminocarbonyl and the like. Examples of the sulfamoyl group include methylsulfamoyl, dimethylsulfamoyl, phenylsulfamoyl and the like. Examples of the sulfonyl group include methylsulfonyl, butylsulfonyl, octylsulfonyl and the like.

R ₁₃ is preferably a hydrogen atom, an alkyl group, or an acyl group, more preferably a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or an acyl group.

Specific examples of the group that can be substituted on the benzene ring represented by X ₁ and X ₂ include alkyl groups having 1 to 25 carbon atoms (methyl, ethyl, propyl, i-propyl group, t-butyl, pentyl, Hexyl, cyclohexyl etc.), cycloalkyl group (cyclohexyl, cyclopentyl etc.), alkynyl group (propargyl etc.), glycidyl group, acrylate group, methacrylate group, aryl group (phenyl etc.), heterocyclic group (pyridyl, thiazolyl, oxazolyl, imidazolyl) , Furyl, pyrrolyl, pyrazinyl, pyrimidinyl, pyridazinyl, selenazolyl, sriphoranyl, piperidinyl, pyrazolyl, tetrazolyl, etc., halogen atom (chlorine, bromine, iodine, fluorine, etc.), alkoxy group (methoxy group, ethoxy group, propyloxy group, pentyl) Oxy group, cyclopenty Ruoxy group, hexyloxy group, cyclohexyloxy group, etc.), aryloxy group (phenoxy group etc.), alkoxycarbonyl group (methoxycarbonyl, ethoxycarbonyl, butoxycarbonyl etc.), aryloxycarbonyl group (phenoxycarbonyl etc.), sulfonamide group (Methanesulfonamide, ethanesulfonamide, butanesulfonamide, hexanesulfonamide, cyclohexanesulfonamide, benzenesulfonamide, etc.), sulfamoyl group (aminosulfonyl, methylaminosulfonyl, dimethylaminosulfonyl, butylaminosulfonyl, hexylaminosulfonyl, cyclohexyl) Aminosulfonyl, phenylaminosulfonyl, 2-pyridylaminosulfonyl, etc.), urethane groups (methylureido, ethylurea, etc.) Id, pentylureido, cyclohexylureido, phenylureido, 2-pyridylureido, etc.), acyl groups (acetyl, propionyl, butanoyl, hexanoyl, cyclohexanoyl, benzoyl, pyridinoyl, etc.), carbamoyl groups (aminocarbonyl, methylaminocarbonyl, dimethyl) Aminocarbonyl, propylaminocarbonyl, pentylaminocarbonyl, cyclohexylaminocarbonyl, phenylaminocarbonyl, 2-pyridylaminocarbonyl, etc.), amide groups (acetamido, propionamide, butanamide, hexaneamide, benzamide, etc.), sulfonyl groups (methylsulfonyl, ethyl) Sulfonyl, butylsulfonyl, cyclohexylsulfonyl, phenylsulfonyl, 2-pyridylsulfonyl, etc.), Honamide group (methylsulfonamide, octylsulfonamide, phenylsulfonamide, naphthylsulfonamide, etc.), amino group (amino, ethylamino, dimethylamino, butylamino, cyclopentylamino, anilino, 2-pyridylamino, etc.), cyano group, nitro Groups, sulfo groups, carboxyl groups, hydroxyl groups, oxamoyl groups and the like. These groups may be further substituted with these groups.

X ₁ and X ₂ are preferably an alkoxy group, an aryloxy group, a carbamoyl group, an amide group, a sulfonamide group, and an amino group, and more preferably an alkoxy group and an amino group. m1 and m2 each represents an integer of 0 to 4, but are preferably 1 to 3 and more preferably 1.

  Of the compounds represented by the general formula (CLB-I), compounds of the following general formula (CLB-II) are preferably used in the present invention.

[Wherein, X ₃ and X ₄ each represents an aliphatic group, an aromatic group, an amino group, an alkoxy group or an aryloxy group. R _11, R ₁₂ and R ₁₃ are each the same meaning as R _11, R ₁₂ and R ₁₃ in the general formula (CLB-I). ]
Examples of the aliphatic group, aromatic group, amino group, alkoxy group and aryloxy group represented by X ₃ and X ₄ are aliphatic represented by X ₁ and X ₂ in the general formula (CLB-I). Examples thereof include the same groups as the specific examples of the group, aromatic group, amino group, alkoxy group and aryloxy group. X ₃ and X ₄ are preferably an alkoxy group, an aryloxy group or an amino group, more preferably an alkoxy group or an amino group.
Of the compounds represented by the general formula (CLB-I), compounds of the following general formula (CLB-III) are particularly preferably used in the present invention.

[Wherein, R ₁₄ , R ₁₅ , R ₁₆ and R ₁₇ each represent a hydrogen atom or an alkyl group. R _11, R ₁₂ and R ₁₃ are each the same meaning as R _11, R ₁₂ and R ₁₃ in the general formula (CLB-I). ]
Specific examples of the alkyl group represented by R ₁₄ , R ₁₅ , R ₁₆ and R ₁₇ include methyl, ethyl, propyl, i-propyl, t-butyl, pentyl, hexyl and the like. These groups may have a substituent at any position, and examples of the substituent include the groups exemplified as the substituent represented by R ₄ in the general formula (RD). R ₁₄ , R ₁₅ , R ₁₆ and R ₁₇ are preferably an alkyl group having 1 to 10 carbon atoms, more preferably methyl or ethyl.

  The compounds represented by these general formulas (CLB-I) to (CLB-III) can be easily synthesized by a conventionally known method, for example, the method described in JP-B-7-45477. Specific examples of the leuco dyes represented by the general formulas (CLB-I) to (CLB-III) are shown below, but the present invention is not limited thereto.

  The addition amount of the cyan coloring leuco dye is usually 0.00001 to 0.05 mol / Ag1 mol, preferably 0.0005 to 0.02 mol / Ag1 mol, more preferably 0.001 to 0.01 mol. / Ag1 mol. The addition ratio of the cyan color-forming leuco dye to the sum of the reducing agents represented by the general formula (RD) is preferably 0.001 to 0.2 in terms of molar ratio, and is preferably 0.005 to 0.1. It is more preferable.

  In the silver salt photothermographic dry imaging material of the present invention, the sum of the maximum densities at the maximum absorption wavelength of a dye image formed with a cyan leuco dye is preferably 0.01 or more and 0.50 or less, more preferably 0.02. It is preferable to develop the color so that it has a value of 0.30 or less, particularly preferably 0.03 or more and 0.10 or less.

  In the present invention, a subtle color tone can be adjusted by using a magenta color developing leuco dye or a yellow color developing leuco dye in addition to the cyan color developing leuco dye.

  As a method for adding the compounds represented by the general formulas (YA) and (YB) and the cyan color-forming leuco dye, they can be added in the same manner as the method for adding the reducing agent represented by the general formula (RD). , Solution form, emulsified dispersion form, solid fine particle dispersion form, etc., it may be contained in the coating solution by any method and contained in the photosensitive material.

  The compounds of general formula (RD), general formula (YA), and (YB) and the cyan color-forming leuco dye are preferably contained in a photosensitive layer (image forming layer) containing an organic silver salt. The other may be contained in the non-photosensitive layer adjacent to the photosensitive layer, or both may be contained in the non-photosensitive layer. When the photosensitive layer is composed of a plurality of layers, they may be contained in separate layers.

(Binder and crosslinking agent)
In the silver salt photothermographic dry imaging material of the present invention, the photosensitive layer and the non-photosensitive layer according to the present invention can contain a binder for various purposes.

  The binder contained in the photosensitive layer according to the present invention can carry an organic silver salt, silver halide grains, a reducing agent, and other components, and a suitable binder is a polymer compound, which is transparent or semi-transparent. Transparent, generally colorless, natural and synthetic polymers, copolymers, and other media that form films, such as:

  Gelatin, gum arabic, poly (vinyl alcohol), hydroxyethyl cellulose, cellulose acetate, cellulose acetate butyrate, poly (vinyl pyrrolidone), casein, starch, polyacrylic acid, polymethylmethacrylic acid, polyvinyl chloride, polymethacrylic acid, copoly (Styrene-maleic anhydride), copoly (styrene-acrylonitrile), copoly (styrene-butadiene), polyvinyl acetals (polyvinyl formal, polyvinyl butyral, etc.), polyesters, polyurethanes, phenoxy resins, polyvinylidene chloride, polyepoxides, There are polycarbonates, polyvinyl acetate, cellulose esters, polyamides and the like. The binder may be hydrophilic or non-hydrophilic.

  Preferred binders for the photosensitive layer of the photothermographic material are polyvinyl acetals, and a particularly preferred binder is polyvinyl butyral. Details will be described later. For non-photosensitive layers such as overcoat layers and undercoat layers, especially protective layers and backcoat layers, cellulose esters which are polymers with higher softening temperatures, especially polymers such as triacetyl cellulose and cellulose acetate butyrate preferable. In addition, as needed, said binder can be used in combination of 2 or more type.

  The above binder is preferably used in combination of at least two kinds.

Such a binder is used in an effective range to function as a binder. The effective range can be easily determined by one skilled in the art. For example, as an index when at least the aliphatic carboxylic acid silver salt is retained in the photosensitive layer, the ratio of the binder to the aliphatic carboxylic acid silver salt is preferably in the range of 15: 1 to 1: 2. That is, it is preferable amount of the binder in the photosensitive layer is a 1.0 to 10.0 g / m ^2. If it is less than 1.0 g / m ² , the density of the unexposed area is significantly increased and may not be used.

  The binder of the photosensitive layer preferably has a glass transition temperature (Tg) of 46 to 200 ° C. after development at a temperature of 100 ° C. or more and 200 ° C. or less. Here, the glass transition temperature (Tg) is a differential scanning calorimeter (DSC) such as EXSTAR 6000 (manufactured by Seiko Denshi), DSC220C (manufactured by Seiko Denshi Kogyo), DSC-7 (manufactured by Perkin Elmer) or the like. The endothermic peak when the heat-developed photosensitive layer is isolated and measured. Generally, a polymer compound has a glass transition temperature (Tg).

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

Tg (copolymer) (° C.) = V ₁ Tg ₁ + v ₂ Tg ₂ +... + V _n Tg _{n
Wherein, v 1, v 2 ··· v} n represents the mass fraction of the monomer in the _{copolymer, Tg 1, Tg 2 ··· Tg} n are each monomer in the copolymer Tg (° C.) of a single polymer obtained from The accuracy of Tg calculated according to the above equation is ± 5 ° C.

  In the photothermographic material of the present invention, a conventionally known polymer compound is used as a binder contained in a photosensitive layer containing an aliphatic carboxylic acid silver salt, photosensitive silver halide grains, a reducing agent, etc. on a support. Can do.

In the present invention, the Tg of at least one binder is preferably 70 to 250 ° C., particularly preferably 70 to 120 ° C.
In addition, it is preferable that at least two kinds having a mass average molecular weight in the range of 10,000 to 1,500,000 are mixed, particularly 10,000 to 80,000 and / or 300,000 to It is preferable that 1,500,000 is at least one.

  Specific examples of such materials include vinyl chloride, vinyl acetate, vinyl alcohol, maleic acid, acrylic acid, acrylic ester, vinylidene chloride, acrylonitrile, methacrylic acid, methacrylic ester, styrene, butadiene, ethylene, vinyl butyral, There are compounds made of polymers or copolymers containing ethylenically unsaturated monomers such as vinyl acetal and vinyl ether as structural units, polyurethane resins, and various rubber resins. Moreover, phenol resin, epoxy resin, polyurethane curable resin, urea resin, melamine resin, alkyd resin, formaldehyde resin, silicone resin, epoxy-polyamide resin, polyester resin and the like can be mentioned.

  These resins are described in detail in “Plastic Handbook” issued by Asakura Shoten. There is no restriction | limiting in particular in these high molecular compounds, If a glass transition temperature (Tg) of the induced | guided | derived polymer exists in the range of 70-250 degreeC, a homopolymer or a copolymer may be sufficient.

  Polymers or copolymers containing such ethylenically unsaturated monomers as structural units include acrylic acid alkyl esters, acrylic acid aryl esters, methacrylic acid alkyl esters, methacrylic acid aryl esters, alkyl cyanoacrylates. Esters, cyanoacrylic acid aryl esters and the like, and the alkyl group and aryl group thereof may or may not be substituted. Specifically, methyl, ethyl, propyl, i-propyl, butyl, i-butyl, sec-butyl, t-butyl, amyl, hexyl, cyclohexyl, benzyl, chlorobenzyl, octyl, stearyl, sulfopropyl, N-ethyl-phenylaminoethyl, 2- (3-phenylpropyloxy) ethyl, dimethyl Aminophenoxyethyl, Rufuryl, tetrahydrofurfuryl, phenyl, cresyl, naphthyl, 2-hydroxyethyl, 4-hydroxybutyl, triethylene glycol, dipropylene glycol, 2-methoxyethyl, 3-methoxybutyl, 2-acetoxyethyl, 2-acetoacetoxyethyl 2-ethoxyethyl, 2-i-propoxyethyl, 2-butoxyethyl, 2- (2-methoxyethoxy) ethyl, 2- (2-ethoxyethoxy) ethyl, 2- (2-butoxyethoxy) ethyl, 2- Examples thereof include diphenylphosphorylethyl, ω-methoxypolyethylene glycol (added mole number n = 6), allyl, dimethylaminoethylmethyl chloride salt and the like.

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

  Of these, particularly preferred examples include methacrylic acid alkyl esters, methacrylic acid aryl esters, and styrenes. Among such polymer compounds, it is preferable to use a polymer compound having an acetal group. The polymer compound having an acetal group is preferable because it is excellent in compatibility with the aliphatic carboxylic acid to be produced and has a great effect of preventing the film from being softened.

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

In the formula, R ₅₁ represents an alkyl group, a substituted alkyl group, an aryl group or a substituted aryl group, but is preferably a group other than an aryl group. R ₅₂ represents an unsubstituted alkyl group, a substituted alkyl group, an unsubstituted aryl group, a substituted aryl group, —COR ₅₃ or —CONHR ₅₃ . R ₅₃ has the same meaning as R ₅₁ . a, b, and c are values representing the mass of each repeating unit in mol (mol)%, a is in the range of 40 to 86 mol%, b is in the range of 0 to 30 mol%, and c is in the range of 0 to 60 mol%. And a number that satisfies a + b + c = 100 mol%.

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

As the polyurethane resin that can be used in the present invention, those having a known structure such as polyester polyurethane, polyether polyurethane, polyether polyester polyurethane, polycarbonate polyurethane, polyester polycarbonate polyurethane, and polycaprolactone polyurethane can be used. For all polyurethane shown here, if _{necessary, -COOM, -SO 3 M, -OSO} 3 M, -P = O (OM) 2, -O-P = O (OM) 2 (M is a hydrogen atom Or represents an alkali metal base), —N (R ₅₄ ) ₂ , —N ⁺ (R ₅₄ ) ₃ (R ₅₄ represents a hydrocarbon group, and a plurality of R ₅₄ may be the same or different), an epoxy group, It is preferable to use one in which at least one polar group selected from —SH, —CN and the like is introduced by copolymerization or addition reaction. The amount of such a polar group is 10 ⁻¹ to 10 ⁻⁸ mol / g, preferably 10 ⁻² to 10 ⁻⁶ mol / g. In addition to these polar groups, it is preferred to have a total of two or more hydroxyl groups, at least one at each polyurethane molecule end. Since hydroxyl groups are cross-linked with polyisocyanate as a curing agent to form a three-dimensional network structure, it is more preferable that they are contained in the molecule. In particular, it is preferable that the hydroxyl group is at the molecular end because the reactivity with the curing agent is high. The polyurethane preferably has 3 or more hydroxyl groups at the molecular terminals, and particularly preferably 4 or more. When polyurethane is used, the glass transition temperature is preferably 70 to 105 ° C., the elongation at break is 100 to 2000%, and the stress at break is preferably 0.5 to 100 N / mm ² .

  The polymer compound represented by the general formula [V] can be synthesized by a general synthesis method described in “Vinyl acetate resin” edited by Ichiro Sakurada (Polymer Chemistry Press, 1962).

  These polymer compounds may be used alone as a binder, or two or more kinds may be blended and used. In the photosensitive silver salt-containing layer (preferably photosensitive layer) of the present invention, the above polymer is used as a main binder. The main binder as used herein refers to “a state in which the polymer occupies 50% by mass or more of the total binder of the photosensitive silver salt-containing layer”. Therefore, other polymers may be blended and used within a range of less than 50% by weight of the total binder. These polymers are not particularly limited as long as the polymers of the present invention are soluble. More preferably, polyvinyl acetate, a polyacrylic resin, a urethane resin, etc. are mentioned.

  It is known that the use of a crosslinking agent with respect to the binder improves film attachment and reduces development unevenness.

  As the crosslinking agent used, various crosslinking agents conventionally used for silver halide photographic light-sensitive materials, for example, aldehyde-based, epoxy-based, ethyleneimine-based, and isocyanate-based materials described in JP-A-50-96216 are used. <Vinylsulfone-based, sulfonic acid ester-based, acryloyl-based, carbodiimide-based, and silane compound-based crosslinking agents can be used. In the present invention, at least one of the crosslinking agents is preferably a polyfunctional carbodiimide-based compound.

  The carbodiimide-based crosslinking agent is a compound having at least two carbodiimide groups and adducts thereof (adducts), and more specifically, aliphatic dicarbodiimides and aliphatic dicarbodiimides having a cyclic group Benzenedicarbodiimides, naphthalene dicarbodiimides, biphenylcarbodiimides, diphenylmethanedicarbodiimides, triphenylmethanedicarbodiimides, tricarbodiimides, tetracarbodiimides, and adducts of these carbodiimides and their carbodiimides Examples include adducts with divalent or trivalent polyalcohols. Such carbodiimides can be produced by reacting the corresponding isocyanates with primary amines in the presence of a phosphorus catalyst, such as a phospholene compound.

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

General formula (CI)
_{R 1 -J 1 -N = C =} N-J 2 - (L) n - (J 3 -N = C = N-J 4 -R 2) v
Any polyfunctional carbodiimide compound can be used as long as it has two or more functional carbodiimide groups, and a compound having the structure of the general formula (CI) is particularly preferable.

In general formula (CI), the alkyl group and aryl group represented by R ₁ and R ₂ are, for example, methyl, ethyl, propyl, butyl, pentyl group, etc. as the alkyl group, and benzene as the aryl group. And heterocyclic groups such as furan, thiophene, dioxane, pyridine, piperazine, morpholine, etc., and these groups are groups bonded by a linking group. May be.

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

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

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

  The polyfunctional carbodiimide crosslinker may be added to any part of the photothermographic material. For example, a support (especially when the support is paper, it can be included in the size composition), photosensitive layer, surface protective layer, intermediate layer, antihalation layer, subbing layer, etc. And can be added to one or more of these layers.

  The amount of the crosslinking agent used is in the range of 0.001 to 2 mol, preferably 0.005 to 1 mol, with respect to 1 mol of silver. Within this range, two or more may be used in combination.

  Examples of silane compounds that can be used as a crosslinking agent include compounds represented by general formula (1) or general formula (2) described in JP-A No. 2001-264930.

  The epoxy compound that can be used as the crosslinking agent is not particularly limited as long as it has one or more epoxy groups and the number of epoxy groups, molecular weight, and the like. The epoxy group is preferably contained in the molecule as a glycidyl group via an ether bond or an imino bond. Moreover, any of a monomer, an oligomer, a polymer, etc. may be sufficient as an epoxy compound, and the number of the epoxy groups which exist in a molecule | numerator is about 1-10 normally, Preferably it is 2-4. When the epoxy compound is a polymer, it may be a homopolymer or a copolymer, and the particularly preferred range of the number average molecular weight Mn is about 2000 to 20000.

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

  An acid anhydride is a compound having at least one acid anhydride group represented by the following structural formula.

-CO-O-CO-
The acid anhydride only needs to have one or more such acid anhydride groups, and the number of acid anhydride groups, molecular weight, and the like are not limited, but in general formula [B] described in JP-A-2003-75953 The compounds represented are preferred.

(Silver saving agent)
The photosensitive layer or the non-photosensitive layer according to the present invention may contain a silver saving agent. As used herein, the silver saving agent refers to a compound that can reduce the amount of silver necessary to obtain a certain silver image density.

  Although various mechanisms for the function of reducing the required silver amount are conceivable, a compound having a function of improving the covering power of developed silver is preferred. Here, the covering power of developed silver refers to the optical density per unit amount of silver. This silver saving agent can be present in the photosensitive layer, the non-photosensitive layer, or both. Preferred examples of the silver saving agent include hydrazine derivative compounds, vinyl compounds, phenol derivatives, naphthol derivatives, quaternary onium compounds, and silane compounds. Specific examples thereof include silver saving agents disclosed in paragraphs “0195” to “0235” of JP2003-270755A.

  Particularly preferred silver saving agents as the silver saving agent according to the present invention are compounds represented by the following general formulas (SE1) and (SE2).

General formula (SE1)
Q ₁ -NHNH-Q ₂
In the formula, Q ₁ represents an aromatic group or a heterocyclic group bonded to —NHNH—Q ₂ at a carbon atom site, and Q ₂ represents a carbamoyl group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a sulfonyl group, Or represents a sulfamoyl group.

In the formula, R ₁ represents an alkyl group, an acyl group, an acylamino group, a sulfonamide group, an alkoxycarbonyl group, or a carbamoyl group. R ₂ represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an aryloxy group, an alkylthio group, an arylthio group, an acyloxy group, or a carbonate group. R ₃ and R ₄ each represents a group that can be substituted on the benzene ring. R ₃ and R ₄ may be connected to each other to form a condensed ring.

In the general formula (SE2), when R ₃ and R ₄ are connected to each other to form a condensed ring, a naphthalene ring is particularly preferable as the condensed ring. When general formula (SE2) is a naphthol compound, R ₁ is preferably a carbamoyl group. Of these, a benzoyl group is particularly preferable. R ₂ is preferably an alkoxy group or an aryloxy group, and particularly preferably an alkoxy group.

(Thermal solvent)
The silver salt photothermographic dry imaging material of the present invention preferably contains a thermal solvent. Here, the thermal solvent is a material capable of lowering the heat development temperature by 1 ° C. or more compared to the silver salt photothermographic dry imaging material containing no thermal solvent, compared to the silver salt photothermographic dry imaging material containing the thermal solvent. It is defined as More preferably, the material can lower the heat development temperature by 2 ° C. or more, and particularly preferably the material that can lower the temperature by 3 ° C. or more. For example, with respect to the photothermographic dry imaging material A containing a thermosolvent, when the photothermographic dry imaging material A from the photothermographic dry imaging material A is B, the photothermographic dry imaging material B is exposed and thermally developed. When the thermal development temperature for obtaining the density obtained by processing at a temperature of 120 ° C. and a thermal development time of 20 seconds with the photothermographic dry imaging material A at the same exposure amount and thermal development time is 119 ° C. or less, To do.

  The thermal solvent has a polar group as a substituent and is preferably represented by the general formula (TS), but is not limited thereto.

General formula (TS)
(Y) _n Z
In General Formula (TS), Y represents an alkyl group, an alkenyl group, an alkynyl group, an aryl group, or a heterocyclic group. Z represents a group selected from a hydroxy group, carboxy group, amino group, amide group, sulfonamide group, phosphoric acid amide group, cyano group, imide, ureido, sulfoxide, sulfone, phosphine, phosphine oxide or nitrogen-containing heterocyclic group. . n represents an integer of 1 to 3, which is 1 when Z is a monovalent group, and is the same as the valence of Z when Z is a divalent or higher group. When n is 2 or more, the plurality of Y may be the same or different.

  Y may further have a substituent, and may have a group represented by Z as a substituent. Y will be described in more detail. In general formula (TS), Y is a linear, branched or cyclic alkyl group (preferably having 1 to 40 carbon atoms, more preferably 1 to 30 carbon atoms, particularly preferably 1 to 25 carbon atoms such as methyl, ethyl, n -Propyl, iso-propyl, sec-butyl, t-butyl, t-octyl, n-amyl, t-amyl, n-dodecyl, n-tridecyl, octadecyl, icosyl, docosyl, cyclopentyl, cyclohexyl and the like. An alkenyl group (preferably having 2 to 40 carbon atoms, more preferably 2 to 30 carbon atoms, particularly preferably 2 to 25 carbon atoms such as vinyl, allyl, 2-butenyl, 3-pentenyl, etc.), an aryl group (Preferably having 6 to 40 carbon atoms, more preferably 6 to 30 carbon atoms, particularly preferably 6 to 25 carbon atoms such as phenyl and p-methyl. Phenyl, naphthyl, etc.), heterocyclic groups (preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 12 carbon atoms such as pyridyl, pyrazyl, imidazolyl, pyrrolidyl, etc. Represents.). These substituents may be further substituted with other substituents. These substituents may be bonded to each other to form a ring.

  Y may further have a substituent, and examples of the substituent include those described in “0015” of JP-A No. 2004-21068. The reason why development activity is achieved by using a thermal solvent is that the thermal solvent melts near the development temperature, so that it is compatible with substances involved in development, and a reaction at a lower temperature than when no thermal solvent is added. This is thought to be possible. Since heat development is a reduction reaction involving a carboxylic acid having a relatively high polarity or a silver ion transporter, it is preferable to form a reaction field having an appropriate polarity with a thermal solvent having a polar group. .

  The melting point of the thermal solvent preferably used in the present invention is 50 ° C. or more and 200 ° C. or less, more preferably 60 ° C. or more and 150 ° C. or less. In particular, in a photothermographic material that emphasizes stability to an external environment such as image storage stability, which is the object of the present invention, a heat solvent having a melting point of 100 ° C. or higher and 150 ° C. or lower is preferable.

  Specific examples of the thermal solvent include compounds described in “0017” of JP-A No. 2004-21068, compounds described in “0027” of US 2002/0025498, MF-1 to MF-3, and MF6. MF-7, MF-9 to MF-12, and MF-15 to MF-22.

Preferably the added amount of thermal solvent is 0.01~5.0g / m ² in the present invention, more preferably 0.05~2.5g / m ^2, more preferably 0.1~1.5g / M ² . The thermal solvent is preferably contained in the photosensitive layer. Moreover, although the said thermal solvent may be used independently, you may use it in combination of 2 or more type. In the present invention, the thermal solvent may be contained in the coating solution by any method such as a solution form, an emulsified dispersion form, or a solid fine particle dispersion form, and may be contained in the photosensitive material.

  Well-known emulsifying dispersion methods include dissolving oil using an oil such as dibutyl phthalate, tricresyl phosphate, glyceryl triacetate or diethyl phthalate, or an auxiliary solvent such as ethyl acetate or cyclohexanone, and mechanically dispersing the emulsified dispersion. The method of producing is mentioned.

  As the solid fine particle dispersion method, the powder of the hot solvent is dispersed in an appropriate solvent such as water by a ball mill, a colloid mill, a vibration ball mill, a sand mill, a jet mill, a roller mill or ultrasonic waves to produce a solid dispersion. A method is mentioned. In this case, a protective colloid (for example, polyvinyl alcohol) or a surfactant (for example, an anionic surfactant such as sodium triisopropylnaphthalenesulfonate (a mixture of three isopropyl groups having different substitution positions)) may be used. Good. In the mills, beads such as zirconia are usually used as a dispersion medium, and Zr and the like eluted from these beads may be mixed in the dispersion. Although it depends on the dispersion conditions, it is usually in the range of 1 ppm to 1000 ppm. If the Zr content in the light-sensitive material is 0.5 mg or less per 1 g of silver, there is no practical problem. The aqueous dispersion preferably contains a preservative (for example, benzoisothiazolinone sodium salt).

(Anti-fogging agent / image stabilizer)
In any constituent layer of the silver salt photothermographic dry imaging material of the present invention, an antifoggant for preventing fogging during storage before heat development, and an image deterioration after heat development are prevented. It is preferable to contain an image stabilizer.

  In the silver salt photothermographic dry imaging material according to the present invention, antifogging and image stabilizers disclosed in many patent publications relating to the imaging material can be used.

  As reducing agents according to the present invention, reducing agents having protons such as bisphenols and sulfonamidophenols are mainly used, so that these hydrogens are stabilized, the reducing agents are deactivated, and silver ions are reduced. It is preferable that a compound capable of preventing and preventing the reaction is contained. Moreover, it is preferable that the compound which can carry out the oxidative bleaching of the silver atom thru | or metal silver (silver cluster) produced | generated at the time of preservation | save of a raw film or an image is contained.

  Specific examples of the compound having these functions include, for example, biimidazolyl compounds, iodonium compounds and halogen atoms described in paragraphs “0096” to “0128” of JP-A-2003-270755 as active species. A compound having at least one repeating unit of a monomer having a halogen radical releasing group as disclosed in JP-A No. 2003-91054, and a vinyl described in paragraph “0013” of JP-A-6-208192 Examples include various antifogging and image stabilizers such as sulfones and / or β-halosulfones and vinyl type inhibitors having an electron-withdrawing group described in Japanese Patent Application No. 2004-234206.

(Toning agent)
The silver salt photothermographic dry imaging material of the present invention forms a photographic image by heat development processing, and a toning agent (toner) for adjusting the color tone of silver as required is usually contained in an (organic) binder matrix. It is preferably contained in a dispersed state.

  Examples of suitable toning agents used in the present invention are RD17029, U.S. Pat. Nos. 4,123,282, 3,994,732, 3,846,136 and 4,021,249. For example, there are the following.

  Imides (eg, succinimide, phthalimide, naphthalimide, N-hydroxy-1,8-naphthalimide); mercaptans (eg, 3-mercapto-1,2,4-triazole); phthalazinone derivatives or metal salts of these derivatives ( For example, phthalazinone, 4- (1-naphthyl) phthalazinone, 6-chlorophthalazinone, 5,7-dimethyloxyphthalazinone, and 2,3-dihydro-1,4-phthalazinedione); phthalazine and phthalic acids ( For example, combinations of phthalic acid, 4-methylphthalic acid, 4-nitrophthalic acid and tetrachlorophthalic acid; phthalazine and maleic anhydride, and phthalic acid, 2,3-naphthalenedicarboxylic acid or o-phenylene acid derivatives and anhydrides thereof Products (eg, phthalic acid, 4-methylphthalic acid, 4 The combination and the like with at least one compound selected from nitrophthalic acid and tetrachlorophthalic anhydride). Particularly preferred toning agents are combinations of phthalazinone or phthalazine with phthalic acids and phthalic anhydrides.

(Fluorosurfactant)
In the present invention, a fluorine-based surfactant represented by the following general formula (SF) is preferable in order to improve film transportability and environmental suitability (accumulation in a living body) in a laser imager (heat development processing apparatus). Used.

General formula (SF)
(R _f − (L) _n −) _p − (Y) _m − (A)
[In the formula, R _f represents a substituent containing a fluorine atom, L represents a divalent linking group having no fluorine atom, Y represents a (p + q) -valent linking group having no fluorine atom, A represents an anionic group or a salt thereof, n and m each represents an integer of 0 or 1, p represents an integer of 1 to 3, and q represents an integer of 1 to 3. However, when q is 1, n and m are not 0 at the same time. ]
In the general formula (SF), R _f represents a substituent containing a fluorine atom. Examples of the substituent containing the fluorine atom include a fluorinated alkyl group having 1 to 25 carbon atoms (for example, trifluoromethyl). Group, trifluoroethyl group, perfluoroethyl group, perfluorobutyl group, perfluorooctyl group, perfluorododecyl group and perfluorooctadecyl group) or fluorinated alkenyl group (for example, perfluoropropenyl group, perfluorobutenyl group) Perfluorononenyl group, perfluorododecenyl group, etc.). R _f preferably has 2 to 8 carbon atoms, more preferably 2 to 6 carbon atoms. R _f preferably has 2 to 12 fluorine atoms, more preferably 3 to 12 fluorine atoms.

  L represents a divalent linking group having no fluorine atom. Examples of the divalent linking group having no fluorine atom include an alkylene group (for example, a methylene group, an ethylene group, a butylene group, etc.), an alkylene group, and the like. Oxy group (methyleneoxy group, ethyleneoxy group, butyleneoxy group, etc.), oxyalkylene group (for example, oxymethylene group, oxyethylene group, oxybutylene group, etc.), oxyalkyleneoxy group (for example, oxymethyleneoxy group, oxy Ethyleneoxy group, oxyethyleneoxyethyleneoxy group, etc.), phenylene group, oxyphenylene group, phenyloxy group, oxyphenyloxy group, or a combination of these groups.

  A represents an anionic group or a salt thereof. For example, carboxylic acid group or a salt thereof (sodium salt, potassium salt and lithium salt), sulfonic acid group or a salt thereof (sodium salt, potassium salt and lithium salt), sulfuric acid half ester Group or a salt thereof (sodium salt, potassium salt and lithium salt), a phosphoric acid group or a salt thereof (sodium salt, potassium salt and the like) and the like.

  Y represents a (p + q) -valent linking group having no fluorine atom. For example, the trivalent or tetravalent linking group having no fluorine atom is composed mainly of a nitrogen atom or a carbon atom. An atomic group is mentioned. n1 represents 0 or an integer of 1, and is preferably 1.

The fluorine-based surfactant represented by the general formula (SF) is an alkyl compound having 1 to 25 carbon atoms into which a fluorine atom is introduced (for example, trifluoromethyl group, pentafluoroethyl group, perfluorobutyl group, perfluorooctyl). Group and a compound having a perfluorooctadecyl group) and an alkenyl compound (for example, a perfluorohexenyl group and a perfluorononenyl group), a trivalent to hexavalent alkanol compound in which no fluorine atom is introduced, and a hydroxyl group, respectively. aromatic compound or a compound obtained by addition reaction and condensation reaction between the hetero compound having 3 or 4 (part R _f of alkanols compounds), further for example, introducing an anionic group (a) with sulfuric acid esterification, etc. Can be obtained.

  Examples of the trivalent to hexavalent alkanol compound include glycerin, pentaerythritol, 2-methyl-2-hydroxymethyl 1,3-propanediol, 2,4-dihydroxy-3-hydroxymethylpentene, and 1,2,6-hexane. Examples include triol, 1,1,1-tris (hydroxymethyl) propane, 2,2-bis (butanol) -3, aliphatic triol, tetramethylolmethane, D-sorbitol, xylitol, D-mannitol and the like.

  Examples of the aromatic compound and hetero compound having 3 to 4 hydroxyl groups include 1,3,5-trihydroxybenzene and 2,4,6-trihydroxypyridine.

  As a method for adding the fluorosurfactant represented by the general formula (SF) of the present invention to the coating solution, it can be added according to a known addition method. That is, it can be dissolved and added in alcohols such as methanol and ethanol, ketones such as methyl ethyl ketone and acetone, polar solvents such as dimethyl sulfoxide and dimethylformamide. Further, fine particles having a size of 1 μm or less can be added after being dispersed in water or an organic solvent by sand mill dispersion, jet mill dispersion, ultrasonic dispersion or homogenizer dispersion. Many techniques for fine particle dispersion are disclosed, but they can be dispersed according to these techniques. The fluorine-based surfactant represented by the general formula (SF) is preferably added to the outermost protective layer.

The amount of the fluorosurfactant represented by the general formula (SF) of the present invention is preferably 1 × 10 ⁻⁸ to 1 × 10 ⁻¹ mol per 1 m ² , and 1 × 10 ⁻⁵ to 1 × 10 ^−2. Mole is particularly preferred. If the range is less than the former range, the charging characteristics may not be obtained. If the range exceeds the former range, the humidity dependency is large and the storage stability under high humidity may be deteriorated.

(Surface layer / surface property modifier, etc.)
The silver salt photothermographic dry imaging material is used for various photosensitive devices in contact with the photothermographic dry imaging material during the winding, rewinding, and transporting of the photosensitive material in the manufacturing process such as coating, drying, and processing. Often undesirably affected by contact between the photothermographic dry imaging materials, such as between the layer side surface and the backing surface. For example, the surface of the photosensitive material may be scratched or slipped, or the transportability of the photosensitive material in a developing device may be deteriorated.

  Therefore, in the silver salt photothermographic dry imaging material of the present invention, in order to prevent scratches on the surface and deterioration of transportability, any one of the constituent layers of the material, particularly on the support. It is preferable that the outermost layer contains a lubricant, a matting agent or the like to adjust the physical properties of the surface of the material.

  In the silver salt photothermographic dry imaging material of the present invention, the outermost layer on the support contains organic solid lubricant particles having an average particle diameter of 1 μm to 30 μm, and these organic solid lubricant particles are dispersed by a polymer dispersant. This is what it is. The melting point of the organic solid lubricant particles is more preferably higher than the heat development processing temperature, and is 80 ° C. or higher, more preferably 110 ° C. or higher.

  The organic solid lubricant particles used in the silver salt photothermographic dry imaging material of the present invention are preferably compounds that lower the surface energy. For example, polyethylene, polypropylene, polytetrafluoroethylene, and copolymers thereof may be pulverized. Examples thereof include formed particles.

  In the silver salt photothermographic dry imaging material of the present invention, the organic solid lubricant particles are particularly preferably a compound represented by the following general formula (OL1).

General formula (OL1)
_{(R 1) p -X 1 -L} -X 2 - (R 2) q
In the formula, each of R ₁ and R ₂ is a substituted or unsubstituted alkyl group having 6 to 60 carbon atoms, an alkenyl group, an aralkyl group or an aryl group, and when p or q is 2 or more, a plurality of R ₁ and R 2 are present. ₂ may be different even in the same each other. X ₁ and X ₂ each represent a divalent linking group containing a nitrogen atom. L represents a substituted or unsubstituted p + q valent alkyl group, alkenyl group, aralkyl group, or aryl group.

  In the light-sensitive material of the present invention, at least one layer on the support contains the compound represented by the general formula (1), and includes a nonionic fluorine-containing surfactant and an anionic fluorine-containing surfactant. It is preferable to contain.

  Although there is no restriction | limiting in particular as a nonionic fluorine-containing surfactant which can be used by this invention, The compound represented with the following general formula (SA) is preferable.

General formula (SA)
Rf _1- (AO) _n -Rf ₂
In the formula, Rf ₁ and Rf ₂ represent a fluorine-containing aliphatic group, and may be the same or different. AO represents a group having at least one alkyleneoxy group, and n represents an integer of 1 to 30.

(Dye, pigment)
In the silver salt photothermographic dry imaging material of the present invention, a filter layer is formed on the same side as or opposite to the photosensitive layer in order to control the amount of light transmitted through the photosensitive layer or the wavelength distribution. It is preferable to contain a dye or pigment in the layer.

  As the dye used, known compounds that absorb light in various wavelength regions can be used depending on the color sensitivity of the photosensitive material.

  For example, when the silver salt photothermographic dry imaging material of the present invention is used as an image recording material by infrared light, a squarylium dye having a thiopyrylium nucleus as disclosed in JP-A-2001-83655 (this specification) Used as a thiopyrylium squarylium dye) and a squarylium dye having a pyrylium nucleus (referred to herein as a pyrylium squarylium dye), or a thiopyrylium croconium dye similar to a squarylium dye, or a pyrylium croconium dye. It is preferable to do.

  The compound having a squarylium nucleus is a compound having 1-cyclobutene-2-hydroxy-4-one in the molecular structure, and the compound having a croconium nucleus is 1-cyclopentene-2-hydroxy- in the molecular structure. It is a compound having 4,5-dione. Here, the hydroxyl group may be dissociated. Hereinafter, in the present specification, these pigments are collectively referred to as squarylium dyes for convenience. As the dye, a compound described in JP-A-8-201959 is also preferable.

(Support)
Examples of the support material used in the silver salt photothermographic dry imaging material of the present invention include various polymer materials, glass, wool cloth, cotton cloth, paper, metal (aluminum, etc.), etc. For handling, a material that can be processed into a flexible sheet or roll is preferable. Therefore, as a support in the photothermographic dry imaging material of the present invention, cellulose acetate film, polyester film, polyethylene terephthalate (PET) film, polyethylene naphthalate (PEN) film, polyamide film, polyimide film, cellulose triacetate film (TAC) Alternatively, a plastic film such as a polycarbonate (PC) film is preferable, and a biaxially stretched PET film is particularly preferable. The thickness of the support is about 50 to 300 μm, preferably 70 to 180 μm.

  In order to improve the charging property, a conductive compound such as a metal oxide and / or a conductive polymer can be included in the constituent layer. These may be contained in any layer, but are preferably contained in the backing layer or the surface protective layer on the photosensitive layer side, the undercoat layer and the like. The conductive compounds described in columns 14 to 20 of US Pat. No. 5,244,773 are preferably used. Among these, in the present invention, the surface protective layer on the backing layer side preferably contains a conductive metal oxide.

Here, the conductive metal oxide is crystalline metal oxide particles, and those containing oxygen defects and those containing a small amount of hetero atoms forming a donor with respect to the metal oxide used are generally used. In particular, it is particularly preferable because of its high conductivity, and the latter is particularly preferable because it does not give fog to the silver halide emulsion. Examples of metal oxides are ZnO, TiO ₂ , SnO ₂ , Al ₂ O ₃ , In ₂ O ₃ , SiO ₂ , MgO, BaO, MoO ₃ , V ₂ O _5, etc., or a composite oxide thereof, especially ZnO, TiO ₂ and SnO ₂ are preferred. As an example of containing a heteroatom, addition Al, or In to ZnO, addition Sb, Nb, P, such as a halogen element relative to SnO _2, In addition, Nb for TiO _2, Ta Etc. are effective. The amount of these different atoms added is preferably in the range of 0.01 to 30 mol%, but particularly preferably 0.1 to 10 mol%. Furthermore, a silicon compound may be added during the production of fine particles in order to improve fine particle dispersibility and transparency.

The metal oxide fine particles used in the silver salt photothermographic dry imaging material of the present invention have electrical conductivity, and the volume resistivity is 10 ⁷ Ω · cm or less, particularly 10 ⁵ Ω · cm or less. These oxides are described in JP-A Nos. 56-143431, 56-120519, 58-62647 and the like. Furthermore, as described in Japanese Examined Patent Publication No. 59-6235, a conductive material in which the above metal oxide is attached to other crystalline metal oxide particles or fibrous materials (such as titanium oxide) may be used. .

The particle size that can be used is preferably 1 μm or less, but if it is 0.5 μm or less, the stability after dispersion is good and it is easy to use. In order to make the light scattering property as small as possible, it is very preferable to use conductive particles of 0.3 μm or less because a transparent photosensitive material can be formed. Further, when the conductive metal oxide is needle-like or fibrous, the length is preferably 30 μm or less and the diameter is preferably 1 μm or less, particularly preferably the length is 10 μm or less and the diameter is 0.3 μm or less. The thickness / diameter ratio is 3 or more. As the SnO _2, are commercially available from Ishihara Sangyo Kaisha, it can be used SNS10M, SN-100P, SN- 100D, the FSS10M like.

(Component layer)
The silver salt photothermographic dry imaging material of the present invention has a photosensitive layer which is at least one image forming layer on a support. Although only the photosensitive layer may be formed on the support, it is preferable to form at least one non-photosensitive layer on the photosensitive layer. For example, a protective layer is preferably provided on the photosensitive layer for the purpose of protecting the photosensitive layer, and the opposite surface of the support is “sticking” between the photosensitive materials or in the photosensitive material roll. In order to prevent “,” a backcoat layer is provided.

  As a binder used in these protective layers and backcoat layers, a polymer having a glass transition point (Tg) higher than that of the photosensitive layer and hardly causing scratches or deformation, such as cellulose acetate, cellulose acetate butyrate, and cellulose acetate propio. Polymers such as nates are selected from the binders described above.

  For gradation adjustment or the like, two or more photosensitive layers may be provided on one side of the support or one or more layers on both sides of the support.

(Application of component layers)
The silver salt photothermographic dry imaging material of the present invention is formed by preparing a coating solution in which the above-described constituent layers are dissolved or dispersed in a solvent, and applying a plurality of these coating solutions simultaneously, followed by heat treatment. It is preferable. Here, "multiple simultaneous multi-layer coating" means that a coating solution for each constituent layer (for example, a photosensitive layer, a protective layer) is prepared, and each layer is repeatedly coated and dried when it is coated on a support. Instead, it means that each constituent layer can be formed in such a state that a multilayer coating and drying process can be performed simultaneously. That is, the upper layer is provided before the remaining amount of all the solvents in the lower layer reaches 70% by mass or less (more preferably 90% by mass or less).

  There are no particular restrictions on the method of applying multiple layers simultaneously to each constituent layer, for example, bar coater method, curtain coating method, dipping method, air knife method, hopper coating method, reverse roll coating method, gravure coating method, and extrusion. A known method such as a coating method can be used.

  Of the various methods described above, the slide coating method and the extrusion coating method are more preferable. These coating methods have been described on the side having the photosensitive layer, but the same applies to the case of coating with undercoating when the back layer is provided. Japanese Unexamined Patent Publication No. 2000-15173 has a detailed description on the simultaneous multilayer coating method in the photothermographic dry imaging material.

In the present invention, the silver coating amount is preferably selected in accordance with the purpose of the silver salt photothermographic dry imaging material, but is 0.3 g / m ² or more for medical purposes. preferably .5g / m ² or less, 0.5 g / m ² or more, 1.5 g / m ² or less is more preferable. Among the applied silver amounts, those derived from silver halide preferably account for 2 to 18%, more preferably 5 to 15%, based on the total silver amount.

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

Furthermore, the coating density of the non-photosensitive long-chain aliphatic carboxylate is 1 × 10 ⁻¹⁷ g or more, 1 × 10 1 per silver halide grain of 0.01 μm or more (equivalent particle diameter equivalent to sphere). ^-14 g or less is preferable, and 1 x 10 ^-16 g or more and 1 x 10 ^-15 g or less are more preferable.

  In the case of coating under the conditions within the above range, preferable results are obtained from the viewpoint of the optical maximum density of the silver image per fixed coating silver amount, that is, the silver coating amount (covering power) and the color tone of the silver image. Is obtained.

In the present invention, the silver salt photothermographic dry imaging material preferably contains a solvent in the range of 5 to 1,000 mg / m ² during development. It is more preferable to adjust so that it may be 10-150 mg / m < ² >. As a result, the photothermographic material has high sensitivity, low fog, and high maximum density. Examples of the solvent include those described in paragraph “0030” of JP-A No. 2001-264930. However, it is not limited to these. These solvents can be used alone or in combination of several kinds.

  The content of the solvent in the photothermographic material can be adjusted by changing conditions such as a temperature condition in a drying process after the coating process. The content of the solvent can be measured by gas chromatography under conditions suitable for detecting the contained solvent.

(Packaging body)
In the case of storing the silver salt photothermographic dry imaging material of the present invention, in order to prevent density change and fog generation over time, or to improve curling, curling, etc., oxygen permeability and / or moisture permeability It is preferable to package with a low packaging material. The oxygen permeability is preferably 50 ml / atm · m ² · day or less at 25 ° C. (where 1 atm is 1.01325 × 10 ⁵ Pa), more preferably 10 ml / atm · m ² · day or less, More preferably, it is 1.0 ml / atm · m ² · day or less. The moisture permeability is preferably 0.01 g / m ² · 40 ° C, relative humidity 90% RH · day or less (according to JIS Z0208 cup method), more preferably 0.005 g / m ² · 40 ° C · relative. humidity 90% RH · day or less, still more preferably not more than 0.001g / m ² · 40 ℃ · RH 90% RH · day.

  Specific examples of packaging materials for silver salt photothermographic dry imaging materials include, for example, JP-A-8-254793, JP-A-2000-206653, JP-A-2000-235241, JP-A-2002-062625, JP-A-2003-2003. 015261, JP 2003-057790, JP 2003-084397, JP 2003-098648, JP 2003-098635, JP 2003-107635, JP 2003-131337, JP 2003-146330. No., JP-A-2003-226439, JP-A-2003-228152. The void ratio in the package is 0.01 to 10%, preferably 0.02 to 5%. Nitrogen sealing is performed so that the nitrogen partial pressure in the package is 80% or more, preferably 90% or more. It is good to do. The relative humidity in the package is 10% to 60%, preferably 40% to 55%.

  Further, in the cutting process and the packaging process, in order to prevent image defects such as scratches and white spots, the cleanliness is US federal standard 209d class 10,000 as disclosed in, for example, Japanese Patent Application Laid-Open No. 2004-341145. It is preferable to work in the following environment.

(Exposure conditions)
Regarding the exposure used for the exposure of the silver salt photothermographic dry imaging material of the present invention or the exposure in the image forming method of the present invention, there are various light sources, exposure times, etc. suitable for obtaining a desired appropriate image. The following conditions can be adopted.

  The silver salt photothermographic dry imaging material of the present invention preferably uses a laser beam when recording an image. In the present invention, it is desirable to use a light source suitable for the color sensitivity imparted to the photosensitive material. For example, when the photosensitive material is sensitive to infrared light, it can be applied to any light source as long as it is in the infrared light range. However, the laser power is high, or the silver salt photothermographic dry imaging material Infrared semiconductor lasers (780 nm, 820 nm) are more preferably used from the standpoint of being transparent.

In particular, the photothermographic dry imaging material of the present invention exhibits its characteristics when it is exposed for a short time with light of high illuminance, preferably with a light amount of 1 mW / mm ² or more. The illuminance here refers to the illuminance when the photosensitive material after heat development has an optical density of 3.0. When exposure is performed at such high illuminance, the amount of light (= illuminance * exposure time) required to obtain a required optical density is reduced, and a high sensitivity system can be designed. More preferably, the amount of light is ² mW / mm ² or more and 50 W / mm ² or less, and more preferably 10 mW / mm ² or more and 50 W / mm ² or less.

Any light source may be used as long as it is as described above, but it can be preferably achieved by using a laser. As a laser preferably used for the photosensitive material of the present invention, a gas laser (Ar ⁺ , Kr ⁺ , He—Ne), a YAG laser, a dye laser, a semiconductor laser, and the like are preferable. In addition, a semiconductor laser and a second harmonic generation element can be used. Further, a blue to violet light emitting semiconductor laser (such as one having a peak intensity at a wavelength of 350 nm to 440 nm) can be used. An example of a blue to purple light emitting high-power semiconductor laser is Nichia's NLHV 3000E semiconductor laser.

  In the present invention, the exposure is preferably performed by laser scanning exposure, but various methods can be adopted as the exposure method. For example, as a first preferred method, there is a method using a laser scanning exposure machine in which the angle formed by the scanning surface of the photosensitive material and the scanning laser beam is not substantially perpendicular.

  Here, “substantially not perpendicular” means that the angle closest to the vertical during laser beam scanning is preferably 55 to 88 degrees, more preferably 60 to 86 degrees, and still more preferably 65 to 84 degrees. , Most preferably 70-82 degrees.

  The beam spot diameter on the exposure surface of the photosensitive material when the laser beam is scanned onto the photosensitive material is preferably 200 μm or less, more preferably 100 μm or less. This is preferable in that a smaller spot diameter can reduce the “shift angle” from the vertical of the laser beam incident angle. The lower limit of the beam spot diameter is 10 μm. By performing such laser scanning exposure, it is possible to reduce image quality deterioration related to reflected light such as generation of interference fringe-like unevenness.

  As a second method, it is also preferable to perform exposure using a laser scanning exposure machine that emits scanning laser light that is a vertical multi. Compared with a longitudinal single mode scanning laser beam, image quality degradation such as occurrence of interference fringe-like unevenness is reduced. In order to make a vertical multiplex, methods such as using return light by combining and applying high-frequency superposition are preferable. Note that the vertical multi means that the exposure wavelength is not single, and the exposure wavelength distribution is usually 5 nm or more, preferably 10 nm or more. The upper limit of the exposure wavelength distribution is not particularly limited, but is usually about 60 nm.

  Furthermore, as a third aspect, it is also preferable to form an image by scanning exposure using two or more laser beams. As such an image recording method using a plurality of laser beams, it is used in an image writing unit of a laser printer or a digital copying machine that writes an image line by line in one scan because of a demand for higher resolution and higher speed. For example, Japanese Patent Laid-Open No. 60-166916 is known. This is a method in which laser light emitted from a light source unit is deflected and scanned by a polygon mirror and imaged on a photoconductor via an fθ lens or the like. This is in principle the same laser scanning optics as a laser imager or the like. Device.

  The image formation of laser light on the photoconductor in the image writing means of a laser printer or digital copying machine is for one line from the image formation position of one laser light for the purpose of writing an image by a plurality of lines in one scan. The next laser beam is imaged by shifting. Specifically, the two light beams are close to each other on the image plane in the sub-scanning direction at an order of several tens of μm, and the print density is 400 dpi (dpi is the number of dots per inch = 2.54 cm). The sub-scanning direction pitch of the two beams is 63.5 μm, and 42.3 μm at 600 dpi. Unlike the method of shifting the resolution in the sub-scanning direction as described above, in the present invention, it is preferable to form an image by condensing two or more lasers at the same place on the exposure surface while changing the incident angle. At this time, the exposure energy on the exposure surface when writing with one normal laser beam (wavelength λ [nm]) is E, and N laser beams used for exposure have the same wavelength (wavelength λ [nm]). ), In the case of the same exposure energy (En), the range of 0.9 × E ≦ En × N ≦ 1.1 × E is preferable. By doing so, energy is secured on the exposure surface, but the reflection of each laser beam to the image forming layer is reduced because the exposure energy of the laser is low, and thus the occurrence of interference fringes is suppressed.

  In the above description, the wavelengths of the plurality of laser beams are the same as λ, but those having different wavelengths may be used. In this case, it is preferable that (λ−30) <λ1, λ2,... Λn ≦ (λ + 30) with respect to λ [nm].

In the image recording methods of the first, second, and third aspects described above, as lasers used for scanning exposure, generally well-known solid lasers such as ruby lasers, YAG lasers, glass lasers; Ne laser, Ar ion laser, Kr ion laser, CO ₂ laser, CO laser, He—Cd laser, N ₂ laser, excimer laser and other gas lasers; InGaP laser, AlGaAs laser, GaAsP laser, InGaAs laser, InAsP laser, CdSnP ₂ lasers, semiconductor lasers such as GaSb lasers; chemical lasers, dye lasers, etc. can be selected and used in a timely manner, but among these, semiconductors with a wavelength of 600-1200 nm due to maintenance and light source size problems It is preferable to use laser light from a laser. In a laser used in a laser imager or a laser image setter, the beam spot diameter on the material exposure surface when scanned with a silver salt photothermographic dry imaging material is generally 5 to 75 μm as a short axis diameter, and a long axis. The diameter is in the range of 5 to 100 μm, and the laser beam scanning speed can be set to an optimum value for each photothermographic dry imaging material depending on the sensitivity and laser power at the lasing wavelength inherent to the silver salt photothermographic dry imaging material. .

(Laser imager development conditions)
The laser imager (heat development processing apparatus) referred to in the present invention has a structure that is uniform and stable over the entire surface of a film supply unit represented by a film tray, a laser image recording unit, and a silver salt photothermographic dry imaging material. A heat developing unit for supplying heat and a conveying unit for discharging the photothermographic dry imaging material image-formed by heat development through laser recording from the film supply unit to the outside of the apparatus.

  It is preferable for the rapid processing to shorten the time interval between the exposure processing and the heat development processing. Furthermore, it is preferable that the exposure process and the heat development process proceed simultaneously. That is, in order to start development and proceed with a part of a sheet that has already been exposed while exposing a part of the sheet-sensitive material, the distance between the exposure part where the exposure process is performed and the development part is 0 cm or more and 50 cm or less. In this way, a series of processing time for exposure and development is extremely shortened. A preferable range of this distance is 3 cm or more and 40 cm or less, and more preferably 5 cm or more and 30 cm or less.

  Here, the exposure part refers to the position where the light from the exposure light source is applied to the silver salt photothermographic dry imaging material, and the development part refers to the position where the photothermographic material is heated for the first time for thermal development. Say.

  In addition, the conveyance speed in the heat development part of a silver salt photothermographic dry imaging material is 20-200 mm / sec, Especially preferably, it is 30-150 mm / sec. By setting the conveyance speed within this range, density unevenness during heat development can be improved and the processing time can be shortened.

  The development conditions for silver salt photothermographic dry imaging materials vary depending on the equipment, equipment, or means used, but typically heat the photothermographic dry imaging material imagewise exposed at a suitable high temperature. The development is performed. The development is performed at about 80 to 200 ° C., preferably about 100 to 140 ° C., more preferably 110 to 130 ° C., preferably 3 to 20 seconds, more preferably 5 to 12 seconds.

  The heating during the development processing of the silver salt photothermographic dry imaging material of the present invention is preferably performed by bringing the surface on the side having the protective layer into contact with the heating means, for uniform heating, It is preferable from the viewpoints of thermal efficiency, workability, and the like, and it is preferable that the surface on the side having the protective layer is conveyed while being in contact with the heat roller, and is developed by heat treatment.

  In the silver salt photothermographic dry imaging material of the present invention, an image obtained by heat development at a heating temperature of 123 ° C. and a development time of 12 seconds has a unit length of diffusion density (Y axis) and common log exposure (X axis). In the characteristic curves shown on the equal orthogonal coordinates, the average gradation of 0.25 to 2.5 is preferably 2.0 to 4.0 in terms of optical density with diffused light. By using such gradations, it is possible to obtain an image with high diagnostic recognizability even if the amount of silver is small.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these. Hereinafter, unless otherwise specified, “%” in the examples represents “mass%”.

Example-1
Polymer synthesis [Evaluation method]
(Amount of organic volatiles)
A calibration curve of n-butyraldehyde was prepared by a method based on JIS-K0114, and the amount of volatiles was quantified under the following headspace gas chromatography conditions. The total peak area obtained by resin chromatography 0.75g, head space part temperature 120 degreeC 10 minutes, gas chromatography (injection part temperature 150 degreeC, detector part temperature 200 degreeC) was converted into the amount of n-butyraldehyde. The amount of aldehyde in the resin was used. However, the first peak with the largest area was excluded from the peak area.

(Glass transition temperature: Tg)
A film obtained by applying and drying a polymer solution dissolved in methyl ethyl ketone (MEK) at a concentration of 20% by mass with a wire bar on a Teflon (registered trademark) plate was peeled off. About 10 mg of the peeled sample was loaded into an aluminum pan, and the glass transition temperature (Tg) of each sample was measured in accordance with JIS K7121 using a differential scanning calorimeter (Seiko Electronics Co., Ltd .: EXSTAR6000). As the temperature raising conditions during the measurement, the temperature was raised at 10 ° C./min from 0 to 200 ° C., the cooling to 0 ° C. was carried out at 20 ° C./min, and this operation was repeated twice to set the thermal transition temperature. Asked.

(Mass average molecular weight)
The polymer was dissolved in tetrahydrofuran (THF) so as to be about 0.1%, and measured by GPC under the following conditions. The molecular weight was calculated in terms of standard polystyrene.

Column: Tosoh Tskel SuperHZM_M x 2, 40 ° C
Eluent: THF
Flow rate: 0.3 (ml / min)
Detection: RI
Injection volume: 10 μl
[Production of polymer]
(Polymer 1)
After 100 g of polyvinyl alcohol (PVA, manufactured by Kuraray Co., Ltd.) having a polymerization degree of 500 and a saponification degree of 99.8% was dissolved in 900 g of distilled water by heating, the temperature was kept at 20 ° C., and 40% of 35% hydrochloric acid was added thereto. Furthermore, 17.5 g of butyraldehyde was added. Then it was cooled to 12 ° C. and 60.5 g of butyraldehyde was added. After the resin was precipitated, the mixture was kept for 30 minutes, and then 110 g of 35% hydrochloric acid was added, and the temperature was raised to 30 ° C. and kept for 10 hours. After completion of the reaction, the solution was washed with distilled water, sodium hydroxide was added to the polyvinyl butyral resin dispersion after washing, and the pH of the solution was adjusted to 7. The solution was held at 50 ° C. for 12 hours and then cooled. At this time, the pH of the solution was 5.4. Next, with respect to the solid content of polyvinyl butyral, the solution was washed with 100 times the amount of distilled water, and after removing the water, 10 times the amount of distilled water was added, and the solution was held at 50 ° C. with stirring for 8 hours, After the dehydration step, the film was dried at 45 ° C. until the mass change per hour became 0.1% or less. The amount of aldehyde contained in polymer 1 was 320 ppm.

(Polymer 2)
Polymer 2 was obtained in the same manner as Polymer 1 except that polyvinyl alcohol having a polymerization degree of 800 and a saponification degree of 99.6% was changed.

(Polymer 3)
Polymer 3 was obtained in the same manner as Polymer 1 except that polyvinyl alcohol having a polymerization degree of 300 and a saponification degree of 99.4% was changed.

(Polymer 4)
Polymer 4 was obtained in the same manner as Polymer 1 except that polyvinyl alcohol having a polymerization degree of 1200 and a saponification degree of 99.5% was changed.

(Polymer 5)
Polymer 5 was obtained in the same manner as Polymer 1 except that polyvinyl alcohol having a polymerization degree of 2500 and a saponification degree of 99.5% was changed.

(Polymer 6)
Polymer 6 was obtained in the same manner as Polymer 1 except that the aldehyde used for acetalization was changed to an aldehyde obtained by mixing butyraldehyde and acetaldehyde in a ratio of 2.5 / 7.5.

(Polymer 7)
Polymer 7 was obtained in the same manner as Polymer 2 except that the aldehyde used for the acetalization was changed to an aldehyde in which butyraldehyde and acetaldehyde were mixed to 2.5 / 7.5.

(Polymer 8)
A polymer 8 was obtained in the same manner as the polymer 3 except that the aldehyde used for acetalization was changed to an aldehyde obtained by mixing butyraldehyde and acetaldehyde in a ratio of 2.5 / 7.5.

(Polymer 9)
A polymer 9 was obtained in the same manner as the polymer 5 except that the aldehyde used for acetalization was changed to an aldehyde obtained by mixing butyraldehyde and acetaldehyde in a ratio of 2.5 / 7.5.

(Polymer 10)
Polymer 1 was obtained in the same manner as Polymer 1 except that the aldehyde used for acetalization was changed to an aldehyde mixed with 5/5 of butyraldehyde and acetaldehyde.

(Polymer 11)
Polymer 11 was obtained in the same manner as Polymer 2 except that the aldehyde used for acetalization was changed to an aldehyde in which butyraldehyde and acetaldehyde were mixed in 5/5.

(Polymer 12)
A polymer 12 was obtained in the same manner as the polymer 5 except that the aldehyde used for acetalization was changed to an aldehyde in which butyraldehyde and acetaldehyde were mixed in 5/5.

(Polymer 13)
Polymer 13 was obtained in the same manner as in Polymer 1 except that the aldehyde used for acetalization was changed from butyraldehyde to acetaldehyde.

(Polymer 14)
A polymer 14 was obtained in the same manner as the polymer 2 except that the aldehyde used for acetalization was changed from butyraldehyde to acetaldehyde.

(Polymer 15)
A polymer 15 was obtained in the same manner as the polymer 5 except that the aldehyde used for acetalization was changed from butyraldehyde to acetaldehyde.

  Table 1 shows the results of measurement of the glass transition temperature (Tg) and mass average molecular weight of the above polymers.

Example-2
<< Preparation of photosensitive silver halide grain emulsion >>
[Preparation of photosensitive silver halide grain emulsion 1]
(Solution A1)
Phenylcarbamoylated gelatin 88.3g
Compound A (* 1) (10% aqueous methanol solution) 10 ml
Potassium bromide 0.32g
Finished to 5429 ml with water (Solution B1)
0.67 mol / L silver nitrate aqueous solution 2635 ml
(Solution C1)
Potassium bromide 51.55g
Potassium iodide 1.47g
Finished to 660 ml with water (Solution D1)
Potassium bromide 154.9g
4.41 g of potassium iodide
K ₃ OsCl ₆ ⁺ K ₄ [Fe (CN) ₆ ]
(Dopant: each 2 × 10 ⁻⁵ mol / Ag equivalent) 50.0 ml
Finished to 1982 ml with water (Solution E1)
0.4 mol / L potassium bromide aqueous solution The following silver potential control amount (Solution F1)
Potassium hydroxide 0.71g
Finished to 20 ml with water (Solution G1)
56% acetic acid aqueous solution 18.0 ml
(Solution H1)
Anhydrous sodium carbonate 1.72 g
Finished to 151 ml with water.
(* 1) Compound _{A: HO (CH 2 CH 2O} ) n (CH (CH 3) CH 2O) 17 (CH 2 CH 2O) mH (m + n = 57)
Using the mixing stirrer described in Japanese Patent Publication No. 58-58288, the solution A1 was adjusted to 4 by simultaneous mixing while controlling the 1/4 amount of the solution B1 and the total amount of the solution C1 to 45 ° C. and pAg 8.09. Addition took 45 minutes to nucleate. After 1 minute, the entire amount of solution F1 was added. During this time, the pAg was adjusted as appropriate using the solution E1. After the elapse of 6 minutes, 3/4 amount of the solution B1 and the whole amount of the solution D1 were added over 14 minutes and 15 seconds by the simultaneous mixing method while controlling to pAg8.09. After stirring for 5 minutes, the entire amount of the solution G1 was added to precipitate the silver halide grain emulsion. The supernatant was removed leaving 2000 ml of the sedimented portion, 10 L of water was added, and after stirring, the silver halide grain emulsion was sedimented again. The remaining portion of 1500 ml was left, the supernatant was removed, 10 L of water was further added, and after stirring, the silver halide grain emulsion was allowed to settle. After leaving 1500 ml of the sedimented portion and removing the supernatant, the solution H1 was added, the temperature was raised to 60 ° C., and the mixture was further stirred for 120 minutes. Finally, the pH was adjusted to 5.8, and water was added so that the amount was 1161 g per mole of silver to obtain a silver halide emulsion.

  The silver halide grains in the photosensitive silver halide grain emulsion 1 prepared as described above are monodispersed with an average sphere equivalent diameter of 0.060 μm, a sphere equivalent diameter variation coefficient of 12%, and a [100] plane ratio of 92%. Cubic silver iodobromide grains. It calculated | required from the average of 1000 particle | grains using the electron microscope. The [100] face ratio of the particles was determined using the Kubelka-Munk method.

  The ratio of the photosensitive silver halide grains having a particle diameter in the photosensitive silver halide grain emulsion 1 of 0.001 μm or more and 0.050 μm or less is 61% by mass of the total photosensitive silver halide grains in terms of silver amount. Met.

[Preparation of photosensitive silver halide grain emulsion 2]
In the preparation of the photosensitive silver halide emulsion 1, the average grain size was 0.035 μm, the grain size variation coefficient was 11%, and the [100] plane, except that the initial addition and the mixing temperature were changed to 25 ° C. A photosensitive silver halide grain emulsion 2 containing monodispersed cubic silver iodobromide grains in a proportion of 91% was obtained.

  The ratio of photosensitive silver halide grains having a grain size of 0.001 μm or more and 0.050 μm or less in the photosensitive silver halide grain emulsion 2 is 94% by mass of the total photosensitive silver halide grains in terms of silver amount. Met.

[Preparation of photosensitive silver halide grain emulsion 3]
In the preparation of the photosensitive silver halide grain emulsion 1, the average grain size was 0.040 μm, the grain size variation coefficient was 12%, except that the initial addition and the mixing temperature were changed to 35 ° C. [100] Monodispersed cubic silver iodobromide grains having an area ratio of 92% were obtained.

  The ratio of photosensitive silver halide grains having a particle size in the photosensitive silver halide grain emulsion 3 of 0.001 μm or more and 0.050 μm or less is 87% by mass of the total photosensitive silver halide grains in terms of silver amount. Met.

<< Preparation of powdered organic silver salt containing silver halide grains >>
[Preparation of silver halide grain-containing powdered organic silver salt A-1]
Organic silver salt particles were prepared using unpurified behenic acid (commercially available reagent). When this behenic acid was analyzed by the analysis method described later, the behenic acid content was 80% by mass. Since the remainder contained arachidic acid and stearic acid, 130.8 g of behenic acid, 67.7 g of arachidic acid, 43.6 g of stearic acid, 2.3 g of palmitic acid using the reagents of arachidic acid, stearic acid and palmitic acid Each organic acid reagent was mixed so as to become 4720 ml of pure water and dissolved at 80 ° C. Next, 540.2 ml of a 1.5 mol / L sodium hydroxide aqueous solution was added, and 6.9 ml of concentrated nitric acid was added, followed by cooling to 55 ° C. to obtain a mixed fatty acid sodium solution. Add 45.3 g of the photosensitive silver halide emulsion 1 and 450 ml of pure water while keeping the temperature of the mixed fatty acid sodium solution at 55 ° C. with the light blocked (hereinafter, the light blocked state). And stirred for 5 minutes. Next, 702.6 ml of 1 mol / L silver nitrate aqueous solution was added over 2 minutes and stirred for 10 minutes to obtain organic silver salt particle dispersion A-1 containing silver halide particles. Thereafter, the obtained silver halide particle-containing organic silver salt particle dispersion A-1 is transferred to a water-washing vessel, deionized water is added thereto, and the mixture is stirred and allowed to stand to disperse the organic silver salt particles containing silver halide particles. The product A-1 was floated and separated, and the lower water-soluble salts were removed. Thereafter, washing with deionized water and drainage were repeated until the electrical conductivity of the drainage reached 2 μS / cm, and centrifugal dehydration was performed to obtain organic silver salt particles A-1 containing cake-like silver halide grains. Using a fluidized bed dryer (midget dryer MDF-64, manufactured by Dalton Co., Ltd.), the organic silver salt particles A-1 containing cake-like silver halide particles are operated in a nitrogen gas atmosphere and at the dryer hot air temperature. Depending on the conditions, it was dried until the water content became 0.1% to obtain a silver halide grain-containing powdered organic silver salt A-1. An infrared moisture meter was used to measure the moisture content of the powdered organic silver salt A-1 containing silver halide grains. As a result of quantifying the amount of behenic acid in the powdered organic silver salt A-1 containing silver halide grains by the following analytical method, the silver behenate contained in the powdered organic silver salt grains A-1 containing silver halide particles The ratio was 54% by mass. As a result of analyzing the mixed organic acid, the heavy metal content was 5 ppm and the iodine value was 1.5.

<Organic silver analysis method>
The silver behenate content was determined as follows. About 10 mg of organic silver salt is accurately weighed and placed in a 200 ml eggplant type Kolben. Add 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, 5 ml of methanol is added from the top of the cooled product, and the material adhering to the cooling pipe is washed into eggplant type Kolben (twice). The obtained reaction solution is extracted with ethyl acetate (100 ml of ethyl acetate and 70 ml of water are added for liquid separation and twice). Vacuum dry for 30 minutes. Place 1 ml of benzanthrone solution (internal standard) in a 10 ml volumetric flask. Dissolve the sample in toluene and place in a volumetric flask. This is measured by GC, mol% from the peak area of each organic acid is determined, and the composition of all organic acids can be known by determining mass%.

  Subsequently, free organic acids that are not organic silver salts are quantified. About 20 mg of an organic silver salt sample is accurately weighed, and 10 ml of methanol is added and ultrasonically dispersed for 1 minute. When it is filtered and the filtrate is dried, free organic acid is extracted. Thereafter, the free organic acid composition 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 total organic acid. The total organic acid minus the free organic acid was defined as the composition of the organic acid present as an organic silver salt.

[Preparation of silver halide grain-containing powdered organic silver salt A-2]
In the preparation of the above-mentioned powdered organic silver salt A-1 containing silver halide grains, a silver halide was prepared in the same manner except that the photosensitive silver halide grain emulsion 2 was used instead of the photosensitive silver halide grain emulsion 1. A powdered organic silver salt A-2 containing particles was prepared. The silver behenate ratio in the powdered organic silver salt A-2 containing silver halide grains was 55% by mass.

[Preparation of silver halide grain-containing powdered organic silver salt A-3]
In the preparation of the above-mentioned powdered organic silver salt A-1 containing silver halide grains, a silver halide was prepared in the same manner except that the photosensitive silver halide grain emulsion 3 was used instead of the photosensitive silver halide grain emulsion 1. A powdered organic silver salt A-3 containing particles was prepared. The silver behenate ratio in the powdered organic silver salt A-2 containing silver halide grains was 54% by mass.

[Preparation of powdered organic silver salt B-1 containing silver halide grains]
In the preparation of the above-mentioned silver halide grain-containing powdered organic silver salt A-1, a silver halide grain-containing powdered organic silver salt B-1 was prepared in the same manner except that potassium hydroxide was used instead of sodium hydroxide. Prepared. The silver behenate ratio in the powdered organic silver salt B-1 containing silver halide grains was 53% by mass.

[Preparation of silver halide grain-containing powdered organic silver salt B-2]
In the preparation of the powdered organic silver salt A-2 containing silver halide grains, the powdered organic silver salt B-2 containing silver halide grains was similarly prepared except that potassium hydroxide was used instead of sodium hydroxide. Prepared. The silver behenate ratio in the powdered organic silver salt B-2 containing silver halide grains was 54% by mass.

[Preparation of silver halide grain-containing powdered organic silver salt B-3]
In the preparation of the above-mentioned silver halide grain-containing powdered organic silver salt A-3, except that potassium hydroxide was used instead of sodium hydroxide, a silver halide grain-containing powdered organic silver salt B-3 was prepared in the same manner. Prepared. The silver behenate ratio in the powdered organic silver salt B-3 containing silver halide grains was 54% by mass.

[Preparation of silver halide grain-containing powdered organic silver salt C-1]
In the preparation of the above-mentioned silver halide grain-containing powdered organic silver salt B-2, except that unpurified behenic acid (commercially available reagent) was used, a powdered organic silver salt C-1 containing silver halide grains was used. Was made. The silver behenate ratio in the powdered organic silver salt B-3 containing silver halide grains was 82% by mass.

<< Preparation of photosensitive emulsion dispersion A-1 >>
The above-mentioned silver halide grain-containing powdered organic silver salt A was dissolved in 14.57 g of methyl ethyl ketone in 1457 g of methyl ethyl ketone and stirred with a dissolver DISPERMAT CA-40M manufactured by VMA-GETZMANN. Preliminary dispersion A-1 was prepared by gradually adding 500 g of -1 and mixing well.

  Media type in which the preliminary dispersion A-1 is filled with 80% of the internal volume of 0.5 mm diameter zirconia beads (Traceram manufactured by Toray Industries, Inc.) using a pump so that the residence time in the mill is 1.5 minutes. This was supplied to a disperser DISPERMAT SL-C12EX type (manufactured by VMA-GETZMANN) and dispersed at a mill peripheral speed of 8 m / sec to prepare photosensitive emulsion dispersion A-1.

<< Preparation of photosensitive emulsion dispersion >>
In the preparation of the photosensitive emulsion dispersion A-1, as shown in Table 2, instead of the powdered organic silver salt A-1 containing silver halide grains, the powdered organic silver salt A- containing silver halide grains was used. Photosensitive emulsion dispersions were prepared in the same manner except that 2, 3, B-1 to B-3, and C-1 were changed to those described for polymer 3, respectively.

<< Evaluation of photosensitive emulsion dispersion >>
(Measurement of number average particle size of powdered organic silver salt)
The particles after dispersion of the powdered organic silver salt in the photosensitive emulsion dispersions A-1 to C-1 prepared above were subjected to 20 ° C. with FPAR-1000 (manufactured by Otsuka Electronics Co., Ltd.) using a dynamic light scattering method. The measurement was performed under the condition of a solid content concentration of 20%.

(Evaluation of aggregation state)
10 g of each of the light-sensitive emulsion dispersions A-1 to C-3 prepared above was collected, and 80 g of methyl ethyl ketone was added and sufficiently stirred. Subsequently, 10 g of the exemplified compound P-9 shown in Table 1 as a binder was added and stirred until it was sufficiently dissolved. This was applied onto a 100 μm transparent polyethylene terephthalate film so as to have a wet film thickness of 100 μm, and dried. The layer thus formed was attached to an appropriate holder with an adhesive, and an ultrathin slice having a thickness of 0.1 to 0.2 μm was produced using a diamond knife in a direction perpendicular to the support surface. The prepared ultra-thin slice 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 TEM). A bright field image was observed at a magnification of 10,000 times, and the image was quickly recorded on a film and punched out as an image.

  In this image, the number of silver halide grains in a certain volume is visually counted, and this is designated as N1. Theoretical halogenation calculated from the amount of silver halide added in the same volume and the grain size. From the silver particle number N2, the aggregation ratio was determined according to the following formula, and this was used as a scale indicating the aggregation state. The numerical value indicates that the closer to 100%, the better the dispersion state and the less the aggregation. Further, the average grain size of silver halide grains was determined according to the above method. The average particle diameter was determined by measuring the equivalent sphere diameter of 500 silver halide grains and using the average value.

Aggregation ratio (%) = (N1 / N2) × 100
Table 2 shows the measurement results obtained as described above.

  As is clear from the results shown in Table 2, the photosensitive emulsion dispersion using the powdered organic silver salt containing silver halide grains prepared using potassium hydroxide was small-sized silver halide grains. However, it is close to the ideal number of silver halide grains, and aggregation is prevented and the powder organic silver salt particle size is small. However, the photosensitive emulsion dispersion using two types of polymers at the time of dispersion further aggregates. Can be seen to be prevented.

Example-2
[Preparation of underdrawn support]
A biaxially stretched polyethylene terephthalate film adjusted to a blue density of 0.115 with Dye-B is subjected to corona discharge treatment on the condition of 10 W / m ² · min. After coating the liquid to a dry film thickness of 0.06 μm, drying at 140 ° C., and subsequently coating the back surface side undercoat upper layer coating liquid to a dry film thickness of 0.2 μm, Dry at 140 ° C. On the other side, the following photosensitive layer side undercoat lower layer coating solution is applied so as to have a dry film thickness of 0.25 μm. After coating to a thickness of 0.06 μm, it was dried at 140 ° C. These were heat-treated at 140 ° C. for 2 minutes to produce a sample with an underdrawn.

<< Back surface side undercoat lower layer coating liquid >>
Copolymer polymer latex of styrene / glycidyl methacrylate / butyl acrylate (20/20/40) (solid content 30%) 16.0 g
Copolymer polymer latex of styrene / butyl acrylate / hydroxymethyl methacrylate (25/45/30) (solid content 30%) 4.0 g
SnO ₂ sol (solid content 10%) (synthesized by the method described in JP-A-10-059720) 91 g
Surfactant A 0.5g
Distilled water was added to make 1000 ml, and a coating solution was obtained.

<< Back surface side undercoat upper layer coating liquid >>
Modified aqueous polyester A (solid content 18%) 215.0 g
Surfactant A 0.4g
True spherical silica matting agent (Seahoster KE-P50 (manufactured by Nippon Shokubai Co., Ltd.)) 0.3 g
Distilled water was added to make 1000 ml, and a coating solution was obtained.

[Synthesis of modified aqueous polyester]
In a heavy reaction mixture reaction vessel, 35.4 parts by weight of dimethyl terephthalate, 33.63 parts by weight of dimethyl isophthalate, 17.92 parts by weight of sodium dimethyl 5-sulfo-isophthalate, 62 parts by weight of ethylene glycol, calcium acetate monohydrate 0.065 parts by mass of salt and 0.022 parts by mass of manganese acetate tetrahydrate were added, and the ester exchange reaction was carried out while distilling off methanol at 170 to 220 ° C. under a nitrogen stream, and then 0.04 of trimethyl phosphate. As a polycondensation catalyst, 0.04 part by weight of antimony trioxide and 6.8 parts by weight of 1,4-cyclohexanedicarboxylic acid are added as a polycondensation catalyst, and a theoretical amount of water is distilled off at a reaction temperature of 220 to 235 ° C. Made. Thereafter, the reaction system was further depressurized and heated for about 1 hour, and finally subjected to polycondensation at 280 ° C. and 133 Pa or less for about 1 hour to obtain a modified aqueous polyester A precursor. The intrinsic viscosity of the precursor was 0.33.

  850 ml of pure water was put into a 2 L three-necked flask equipped with a stirring blade, a reflux condenser, and a thermometer, and 150 g of the precursor was gradually added while rotating the stirring blade. After stirring for 30 minutes at room temperature, the mixture was heated to an internal temperature of 98 ° C. over 1.5 hours, and heated and dissolved at this temperature for 3 hours. After completion of the heating, the mixture was cooled to room temperature over 1 hour and allowed to stand overnight to prepare a precursor solution having a solid concentration of 15% by mass.

  1800 ml of the precursor solution was placed in a 3 L four-necked flask equipped with a stirring blade, a reflux condenser, a thermometer, and a dropping funnel, and the internal temperature was heated to 80 ° C. while rotating the stirring blade. To this, 6.52 ml of a 24% aqueous solution of ammonium peroxide was added, and a monomer mixture (31 g of styrene, 31 g of acetoacetoxyethyl methacrylate, 61 g of glycidyl methacrylate, 7.6 g of n-butyl acrylate) was added dropwise over 30 minutes. The reaction was continued for another 3 hours. Then, it cooled to 30 degrees C or less, and filtered, and prepared the solution of the modified aqueous polyester whose solid content concentration is 18 mass%.

<< Coating liquid for photosensitive layer side undercoat >>
Styrene / acetoacetoxyethyl methacrylate / glycidyl methacrylate / n-butyl acrylate (40/40/20 / 0.5)
Copolymer polymer latex (solid content 30%) 70g
Surfactant A 0.3g
Distilled water was added to make 1000 ml, and a coating solution was obtained.
<< Photosensitive layer side undercoat upper layer coating solution >>
Modified aqueous polyester (solid content 18%) 80.0g
Surfactant A 0.4g
True spherical silica matting agent Seahoster KE-P50 (made by Nippon Shokubai Co., Ltd.) 0.3g
Distilled water was added to make 1000 ml, and a coating solution having a solid content concentration of 0.5% was obtained.

[Coating of photosensitive layer, surface protective layer and back layer]
A photosensitive layer is provided on the photosensitive layer side of the undercoated sample so that the total silver amount is 1.3 g / m ² , and the wet weight is 19 g / m ² on the photosensitive layer. A surface protective layer was applied in multiple layers. Subsequently, a back layer was applied on the opposite photosensitive layer surface side undercoat so that the wet weight was 39 g / m ² . The drying was performed at 60 ° C. for 15 minutes. A heat-developable photosensitive material was obtained by carrying out heat treatment at 79 ° C. for 10 minutes while conveying the sample coated on both sides.

<< Preparation of photosensitive layer coating solution >>
The same amount of methyl ethyl ketone was added to 1670 g of the organic silver salt dispersion, and the mixture was kept at 18 ° C. with stirring. 12.6 g of bis (dimethylacetamide) dibromobromate (11% methanol solution) was added and stirred for 1 hour. Subsequently, 20.1 g of calcium bromide (11% methanol solution) was added and stirred for 30 minutes. Further, a stabilizer solution and an infrared sensitizing dye solution were added and stirred for 1 hour, and then the temperature was lowered to 13 ° C. and further stirred for 30 minutes. While maintaining the temperature at 13 ° C., 416 g of polymer 1 was added and dissolved. After confirming dissolution, 19.8 g of tetrachlorophthalic acid (13% methyl ethyl ketone solution) was added, and the following additives were added at intervals of 15 minutes while continuing stirring. Finally, the photosensitive silver halide dispersion was added. It added and it was set as the photosensitive layer coating liquid. The addition amount of the photosensitive silver halide dispersion was added so that the silver amount derived from the photosensitive silver halide dispersion was equivalent to 6.5% with respect to the silver amount derived from the organic silver salt dispersion.

Phthalazine 12.4g
Desmodur N3300 (Mobay, aliphatic isocyanate) 17.6 g
Antifoggant solution below Developer solution Below <Preparation of infrared sensitizing dye solution>
300 mg of infrared sensitizing dye-1, 400 mg of infrared sensitizing dye-2, 130 mg of 5-methyl-2-mercaptobenzimidazole, 21.5 g of 2-chloro-benzoic acid, 2.5 g of sensitizing dye solubilizer An infrared sensitizing dye solution was prepared by dissolving in 135 g of methyl ethyl ketone.

<Preparation of stabilizer solution>
A stabilizer solution was prepared by dissolving 0.9 g of a stabilizer and 0.3 g of potassium acetate in 14 g of methanol.

<Preparation of developer solution>
120 g of developer, 9 g of 4-methylphthalic acid, and 1.4 g of cyan leuco dye (Exemplary Compound 1) were dissolved in methyl ethyl ketone and finished to 1200 g to obtain a developer solution.

<Preparation of antifoggant solution>
11.6 g of tribromomethylsulfonylpyridine was dissolved in methyl ethyl ketone and finished to 180 g to obtain an antifoggant solution.

<< Preparation of surface protective layer coating liquid >>
Methyl ethyl ketone 1056g
148 g of cellulose acetate propionate (Eastman Chemical Co., CAP141-20)
6 g of polymethyl methacrylate (Rohm and Haas, Paraloid A21)
Matt dispersion (average particle size of 4 μm silica with a dispersion degree of 10%, solid content concentration of 1.7%)
170g
_{CH 2 = CHSO 2 CH 2 CH} (OH) CH 2 SO 2 CH = CH 2 3.6g
Benzotriazole 2g
C ₉ F ₁₇ O (CH ₂ CH ₂ O) ₂₃ C ₉ F ₁₇ 5.4 g
<Preparation of back layer coating solution>
Methyl ethyl ketone 1350g
121 g of cellulose acetate propionate (manufactured by Eastman Chemical Co., CAP482-20)
Dye-A 0.23g
Dye-B 0.62g
Fluorine acrylic copolymer (Daikin Industries, Ltd., Optoflon FM450)
1.21 g
Amorphous saturated copolyester (byron 240P, manufactured by Toyobo Co., Ltd.)
18.1 g
Matting agent dispersion liquid C ₉ F ₁₇ O (CH ₂ CH ₂ O) ₂₃ C ₉ F ₁₇ 5.21 g
LiO ₃ S—CF ₂ CF ₂ CF ₂ —SO ₃ Li 0.81 g
2 g of ethylenebisstearic acid amide was added to 90 g of MEK in which 2 g of cellulose acetate propionate (manufactured by Eastman Chemical Co., CAP482-20) was dissolved. This matting agent solution was dispersed for 30 minutes with an ultrasonic disperser (manufactured by Alex Corporation, trade name: Ultrasonic Generator, frequency 25 kHz, 600 W) to obtain a mat dispersion.

  Table 3 shows the results of evaluation of visual applicability of the photosensitive layer of the photothermographic material produced as described above, the density of the lowest density portion (fogging density), the density of the highest density part, and the image storage stability by the Shakasten light resistance test. Shown in

<Evaluation of image storage stability after development>
As described below, the image density after development was evaluated by measuring the minimum density and the maximum density change rate under a certain condition.

(1) Measurement of minimum density (Dmin) change rate Each heat-developed sample prepared by the same method as the above sensitivity measurement was placed on a sample surface with a commercially available white fluorescent lamp in an environment of 45 ° C. and 55% RH. It arrange | positioned so that illumination intensity might be 500 lux, and performed continuous irradiation for 3 days. The minimum concentration (D2) of the sample irradiated with the fluorescent lamp and the minimum concentration (D1) of the sample not irradiated with the fluorescent lamp were respectively measured, and the minimum concentration change rate (%) was calculated from the following equation.

Minimum density change rate = D2 / D1 x 100 (%)
(2) Measurement of maximum density (Dmax) change rate After each heat-development-treated sample prepared by the same method as the measurement of the minimum density change rate was left in an environment of 25 ° C and 45 ° C for 3 days, The change in maximum density was measured, and the rate of change in image density was measured as described below, and this was used as a measure of image preservation.

Image density change rate = (maximum density of sample stored at 45 ° C./maximum density of sample stored at 25 ° C.) × 100 (%)
<Evaluation of image color tone of sample after development>
The above-mentioned fog, the highest density, and the angular heat development processed sample of which the relative sensitivity was measured, each wedge density part was measured with CM-3600d (manufactured by Minolta Co., Ltd.), and u ^* , v ^* or a ^* , b ^* Calculated. The measurement conditions at that time were F7 light source as the light source, the viewing angle was 10 °, and the measurement was performed in the transmission measurement mode. Plotting u ^* , v ^* or a ^* , b ^* measured on a graph with u ^* or a ^{* on} the horizontal axis and v ^* or b ^{* on the} vertical axis to obtain a linear regression line, multiple determination R ² , intercept and The slope was determined.

<Evaluation of density unevenness>
Under the same exposure conditions as those described in the above-mentioned exposure and development processing, exposure was performed so that the density was 1.5, and the development temperature and speed were changed to perform the development processing. At that time, the cooling fan was adjusted so that the surface temperature of the sample when it came out to the accumulating section by the developing processor was 40 ° C. or less.

  The produced samples were visually evaluated for density unevenness in five stages according to the following criteria. If the level is B or higher, there is no serious problem on the actual product.

A: No unevenness is observed B: Slightly weak unevenness is recognized C: Weak unevenness is recognized D: Slightly strong unevenness is recognized E: Strong unevenness is recognized

  As is apparent from the results shown in Table 3, the covering power is improved when the powdered organic silver salt is prepared using potassium hydroxide and has a small particle size and contains silver halide particles having good dispersibility. Although the maximum density is increased, it can be seen that the storage stability and color tone are deteriorated. On the other hand, in the case of using two or more polymers in combination, the applicability is not deteriorated, the occurrence of unevenness is hardly observed, and the increase in fog during storage is suppressed.

It is a figure which shows the example of the organic silver salt manufacturing apparatus of this invention.

Explanation of symbols

11 Preparation Tank for Additive Solution 12 Preparation Tank for Additive Solution 13 Flow Detector for Additive Solution 14 Pump for Additive Solution 15 Flow Detector for Additive Solution 16 Pump for Additive Solution 17 17 Static Mixer 18 Heat Exchange 19 Tank for product liquid

Claims (13)

A silver salt photothermographic dry imaging material having a photosensitive layer containing a non-photosensitive aliphatic carboxylic acid silver salt particle, a photosensitive silver halide particle, a silver ion reducing agent, and a binder on a support. Silver salt photothermographic photographs, wherein the aliphatic carboxylate silver salt particles have a number average particle size of 0.01 μm or more and 0.60 μm or less, and contain two or more polymer compounds as the binder. Dry imaging material. The silver salt photothermographic dry imaging material according to claim 1, wherein at least one of the binders has a glass transition temperature (Tg) of 70 ° C. or higher and 250 ° C. or lower. 3. The silver salt photothermographic dry imaging material according to claim 1, wherein at least one of the binders is a polymer compound having a mass average molecular weight of 10,000 or more and 80,000 or less. The silver salt photothermographic dry imaging material according to any one of claims 1 to 3, wherein at least one of the binders is a polymer compound having a mass average molecular weight of 300,000 to 1,500,000 or less. . 5. The silver salt photothermographic dry imaging material according to claim 1, wherein an organic volatile substance contained in at least one of the binders is 500 ppm or less. The silver salt photothermographic dry imaging material according to any one of claims 1 to 5, wherein at least one of the binders contains an antioxidant. The silver salt photothermographic dry imaging material according to any one of claims 1 to 6, wherein at least one of the polymer compounds contained as the binder is a polyvinyl acetal resin. The non-photosensitive aliphatic carboxylic acid silver salt particles are obtained by mixing an organic acid metal salt soap formed by adding an alkali metal salt other than sodium to an aliphatic carboxylic acid and a water-soluble silver compound. The silver salt photothermographic dry imaging material according to claim 1, wherein the silver salt photothermographic dry imaging material is an acid silver salt particle. The ratio of the photosensitive silver halide grains having a particle size of 0.01 μm or more and 0.05 μm or less to the total amount of the photosensitive silver halide grains is 50% by mass or more in terms of silver, and 8. The silver salt photothermographic dry imaging material according to any one of 1 to 7, wherein the photosensitive aliphatic carboxylic acid silver salt particles have a number average particle diameter of 0.01 μm or more and 0.60 μm or less. The silver salt photothermal energy according to any one of claims 1 to 8, wherein 80% by mass or more and 99.9% by mass or less of the non-photosensitive aliphatic carboxylic acid silver salt particles are silver behenate. Photo dry imaging material. The silver salt photothermographic dry imaging material according to claim 1, comprising a compound that develops cyan during development. The silver salt photothermographic dry imaging material according to any one of claims 1 to 11, wherein the coated silver amount is 0.5 g / m ² or more and 1.5 g / m ² . An image forming method, wherein an image is formed by a laser imager using the silver salt photothermographic dry imaging material according to claim 1.

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