JP2006309107A - Thermographic method of silver salt photothermographic dry imaging material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermal processing method of a silver salt photothermographic dry imaging material which satisfies both rapid development and storage stability before processing. <P>SOLUTION: In the thermal processing method of a silver salt photothermographic dry imaging material comprising light-insensitive aliphatic carboxylic acid silver salt particles, light-sensitive silver halide grains, a reducing agent for silver ions and a binder, the light-insensitive aliphatic carboxylic acid silver salt particles are comprised of 70-99.99 mol% of silver behenate and have an average sphere equivalent diameter of 0.05-0.5 μm and a standard deviation showing a particle size distribution being ≤0.3. The silver salt photothermographic dry imaging material is processed with a developing machine having a preheating zone where it is heated to 70-100°C immediately before a thermal development step. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention is a silver salt photothermographic dry imaging material (photothermographic dry imaging material, photothermographic photosensitive material, which contains a non-photosensitive organic silver salt, photosensitive silver halide grains, a binder and a silver ion reducing agent on a support. The present invention relates to a heat development processing method of a heat development photosensitive material (also simply referred to as a heat development material or a photosensitive material).

  Conventionally, in the fields of medical treatment and printing plate making, waste liquid from wet processing of image forming materials has been a problem in terms of workability. In recent years, reduction of waste processing liquid has been strongly desired from the viewpoint of environmental conservation and space saving. ing. Therefore, silver salt photothermographic dry imaging materials capable of forming an image only by applying heat have been put into practical use and are rapidly spreading in the above fields.

  The photothermographic dry imaging material itself has been proposed for a long time (see, for example, Patent Documents 1 and 2).

  This silver salt photothermographic dry imaging material is usually processed by a heat development processing apparatus called a laser imager which forms an image by applying stable heat to the material. As described above, with the rapid spread in recent years, a large amount of this laser imager has been supplied to the market. In recent years, there has been a demand for a compact laser imager and rapid processing.

  For this purpose, it is essential to improve the characteristics of the photothermographic dry imaging material. In order to obtain a sufficient density of a photographic image even if rapid processing is performed, the covering power is increased by increasing the number of coloring points by using silver halide grains having a small average grain size (for example, Patent Document 3). 4), or a highly active reducing agent having a secondary or tertiary alkyl group (see, for example, Patent Document 5), or a development accelerator such as a hydrazine compound, a vinyl compound, a phenol derivative, or a naphthol derivative. It is effective to use (see, for example, Patent Documents 6 and 7). However, the silver salt photothermographic dry imaging material contains an organic silver salt, photosensitive silver halide grains and a reducing agent regardless of before and after thermal development. For this reason, there is an unavoidable problem in realizing rapid processing that fog is likely to occur during the storage period before heat development, and attempts have been made to improve it, but it has still reached a sufficient level to meet market demands. There is no current situation (for example, see Patent Document 8).

Further, as a response from the apparatus side to the rapid processing, a technique of performing thermal development while transporting at 23 mm / second or more, or performing thermal development simultaneously with exposure is disclosed (for example, see Patent Documents 9 and 10).
US Pat. No. 3,152,904 (Claims) US Pat. No. 3,457,075 (Claims) JP-A-11-295844 (Claims) JP 11-352627 A (Claims, Examples) JP 2001-209145 A (Claims) JP 2002-6443 A (Claims) JP 2003-66558 A (Claims) JP-A-6-208192 (paragraph numbers 0003 to 0007) US Patent Application Publication No. 2004/0058281 (Claims) JP-A-2004-85763 (Claims)

  The present invention has been made in view of the above-described background circumstances, and an object of the present invention is to provide a thermal development processing method for a silver salt photothermographic dry imaging material that achieves both rapid development and storage stability before processing. .

  The above object of the present invention can be achieved by the following configuration.

(Claim 1)
Non-photosensitive aliphatic carboxylic acid silver salt particles, photosensitive silver halide particles, silver ion reducing agent, and silver salt photothermographic dry imaging material having heat-development processing method, wherein the non-photosensitive aliphatic carboxylic acid silver salt The grains are composed of 70 to 99.99 mol% silver behenate, the sphere equivalent average diameter is 0.05 to 0.5 μm, the standard deviation indicating the particle size distribution is 0.3 or less, and the silver salt A method for thermally developing a silver salt photothermographic dry imaging material, characterized in that the photothermographic dry imaging material is processed with a developing machine having a preheat zone that heats the photothermographic dry imaging material to 70 ° C or higher and 100 ° C or lower immediately before the thermal development step.

(Claim 2)
The non-photosensitive aliphatic carboxylate silver salt particles of the silver salt photothermographic dry imaging material used in the heat development processing method according to claim 1 are simultaneously metered and mixed with an aqueous solution or dispersion of a fatty acid alkali metal salt and an aqueous silver nitrate solution. A silver salt photothermographic dry imaging material heat-development processing method, wherein the non-photosensitive aliphatic carboxylic acid silver salt particles are formed.

(Claim 3)
The non-photosensitive aliphatic carboxylic acid silver salt particles of the silver salt photothermographic dry imaging material used in the heat development processing method according to claim 1, an aqueous solution or aqueous dispersion having a fatty acid alkali metal salt concentration of 1 to 5% by mass; A non-photosensitive aliphatic carboxylic acid silver salt prepared by simultaneously metering and mixing an aqueous silver nitrate solution having a concentration of 1 to 15% by mass and a molar ratio of the silver nitrate to the fatty acid alkali metal salt being 0.9 to 1.1 A method for thermally developing a silver salt photothermographic dry imaging material, characterized by comprising salt particles.

(Claim 4)
A non-photosensitive aliphatic carboxylic acid silver salt particle of a silver salt photothermographic dry imaging material used in the heat development processing method according to claim 1 or 3, wherein the fatty acid alkali metal salt aqueous solution or aqueous dispersion and silver nitrate aqueous solution are transferred. A method for thermally developing a silver salt photothermographic dry imaging material, characterized in that it is non-photosensitive aliphatic carboxylic acid silver salt particles formed by simultaneous metering and mixing.

(Claim 5)
The non-photosensitive aliphatic carboxylic acid silver salt particles of the silver salt photothermographic dry imaging material used in the heat development processing method according to claim 1, 3 or 4 comprise an aqueous solution or aqueous dispersion of a fatty acid alkali metal salt and an aqueous silver nitrate solution. Silver salt photothermographic drying characterized by non-photosensitive aliphatic carboxylic acid silver salt particles formed by simultaneous metering and mixing, washed with water at 50 ° C. or lower and dried at a phase transition temperature or lower. Thermal development processing method of imaging material.

(Claim 6)
A non-photosensitive aliphatic carboxylate silver salt particle of a silver salt photothermographic dry imaging material used in the heat development processing method according to claim 1, 3, 4, or 5 is an aqueous solution or dispersion of a fatty acid alkali metal salt and an aqueous silver nitrate solution. Silver salt photothermographic dry imaging characterized by non-photosensitive aliphatic carboxylic acid silver salt grains formed by simultaneous metering and mixing in the absence of said photosensitive silver halide grains Heat development processing method of material.

(Claim 7)
Non-photosensitive aliphatic carboxylic acid silver salt particles, photosensitive silver halide particles, silver ion reducing agent, and silver salt photothermographic dry imaging material having heat-development processing method, wherein the non-photosensitive aliphatic carboxylic acid silver salt A silver salt photothermographic dry particle comprising 70 to 99.99 mol% silver behenate, having a sphere equivalent average diameter of 0.05 to 0.5 μm and a standard deviation indicating a particle size distribution of 0.3 or less. A silver salt photothermographic dry imaging material characterized in that the imaging material is processed in a developing machine having a slow cooling zone in which the development is stopped by adjusting the temperature to a temperature lower by 10 to 20 ° C. immediately after the heat development step. Thermal development processing method.

(Claim 8)
The non-photosensitive aliphatic carboxylate silver salt particles of the silver salt photothermographic dry imaging material used in the heat development processing method according to claim 7 are simultaneously metered and mixed with an aqueous solution or aqueous dispersion of a fatty acid alkali metal salt and an aqueous silver nitrate solution. A silver salt photothermographic dry imaging material heat-development processing method, wherein the non-photosensitive aliphatic carboxylic acid silver salt particles are formed.

(Claim 9)
The non-photosensitive aliphatic carboxylic acid silver salt particles of the silver salt photothermographic dry imaging material used in the heat development processing method according to claim 7 are an aqueous solution or aqueous dispersion having a fatty acid alkali metal salt concentration of 1 to 5% by mass; A non-photosensitive aliphatic carboxylic acid silver salt prepared by simultaneously metering and mixing an aqueous silver nitrate solution having a concentration of 1 to 15% by mass and a molar ratio of the silver nitrate to the fatty acid alkali metal salt being 0.9 to 1.1 A method for thermally developing a silver salt photothermographic dry imaging material, characterized by comprising salt particles.

(Claim 10)
The non-photosensitive aliphatic carboxylic acid silver salt particles of the silver salt photothermographic dry imaging material used in the heat development processing method according to claim 7 or 9, wherein the fatty acid alkali metal salt aqueous solution or aqueous dispersion and silver nitrate aqueous solution are transferred. A method for thermally developing a silver salt photothermographic dry imaging material, characterized in that it is non-photosensitive aliphatic carboxylic acid silver salt particles formed by simultaneous metering and mixing.

(Claim 11)
The non-photosensitive aliphatic carboxylic acid silver salt particles of the silver salt photothermographic dry imaging material used in the thermal development processing method according to claim 7, 9 or 10 comprise an aqueous solution or aqueous dispersion of a fatty acid alkali metal salt and an aqueous silver nitrate solution. Silver salt photothermographic drying characterized by non-photosensitive aliphatic carboxylic acid silver salt particles formed by simultaneous metering and mixing, washed with water at 50 ° C. or lower and dried at a phase transition temperature or lower. Thermal development processing method of imaging material.

(Claim 12)
A non-photosensitive aliphatic carboxylate silver salt particle of a silver salt photothermographic dry imaging material used in the thermal development processing method according to claim 7, 9, 10, or 11 is an aqueous solution or aqueous dispersion of a fatty acid alkali metal salt and an aqueous silver nitrate solution. Silver salt photothermographic dry imaging characterized by non-photosensitive aliphatic carboxylic acid silver salt grains formed by simultaneous metering and mixing in the absence of said photosensitive silver halide grains Heat development processing method of material.

(Claim 13)
The silver salt photothermographic dry imaging material used in the method for thermal development of a silver salt photothermographic dry imaging material according to any one of claims 1 to 12 is subjected to heat development at a development temperature for 5 to 10 seconds. A method for thermally developing a silver salt photothermographic dry imaging material.

(Claim 14)
The heat development processing method for a silver salt photothermographic dry imaging material according to claim 13, wherein the heat development processing is carried out by a heat developing machine having a heat-retaining zone for maintaining the development temperature in the developing section.

(Claim 15)
The non-photosensitive aliphatic carboxylic acid silver salt particles and the photosensitive silver halide of the silver salt photothermographic dry imaging material used in the heat development processing method of the silver salt photothermographic dry imaging material according to any one of claims 1 to 14. A method for thermally developing a silver salt photothermographic dry imaging material, characterized by thermally developing a silver salt photothermographic dry imaging material having a total silver content of 0.8 to 1.5 g / m ² .

  According to the present invention, it is possible to provide a thermal development processing method for a silver salt photothermographic dry imaging material that achieves both rapid development and storage stability before processing.

  The present invention will be described in more detail.

[Non-photosensitive aliphatic carboxylic acid silver salt particles]
The non-photosensitive aliphatic carboxylic acid silver salt that can be used in the present invention is relatively stable to light, but is 80 ° C. or higher in the presence of the exposed photosensitive silver halide and reducing agent. It is a silver salt that functions as a silver ion supplier when heated to form a silver image. The non-photosensitive aliphatic carboxylic acid silver salt may be any aliphatic carboxylic acid salt capable of supplying silver ions that can be reduced by a reducing agent. The silver salt of an aliphatic carboxylic acid is particularly preferably a silver salt of a long-chain aliphatic carboxylic acid (having 10 to 30 carbon atoms, preferably 15 to 28 carbon atoms). Preferred examples of the aliphatic carboxylic acid silver salt include silver lignocerate, silver behenate, silver arachidate, silver stearate, silver oleate, silver laurate, silver caproate, silver myristate, silver palmitate, erucic acid. Including silver and mixtures thereof. In the present invention, the aliphatic carboxylic acid silver salt contains 70 to 99.99 mol% of silver behenate. Further, it is preferable to contain 70 mol% or more and less than 99 mol% silver behenate, and more preferably 80 mol% or more and less than 90 mol% silver behenate. In addition, it is preferable to use an aliphatic carboxylic acid silver salt having a silver erucate content of 2 mol% or less, more preferably 1 mol% or less, and still more preferably 0.1 mol% or less.

  The non-photosensitive aliphatic carboxylic acid silver salt particles of the present invention have a sphere equivalent diameter of 0.05 μm or more and 0.5 μm or less. Preferably, it is 0.10 μm or more and 0.5 μm or less. The particle size distribution is preferably monodisperse. The monodispersity can be expressed by the standard deviation of the average diameter, and the standard deviation of the aliphatic carboxylic acid silver salt particles of the present invention is 0.3 or less. Furthermore, it is preferable that it is 0.2 or less.

  Measurement of particle size and size distribution in this case includes laser diffraction method, centrifugal sedimentation light transmission method, X-ray transmission method, electrical detection band method, shading method, ultrasonic attenuation spectroscopy, method of calculating from image, etc. The particle size distribution can be determined by a known particle size distribution measuring method. Among them, for fine particles, a laser diffraction method and a method of calculating from an image are preferable. Furthermore, the laser diffraction method is preferable, and the aliphatic carboxylic acid silver salt particles dispersed in the liquid can be performed by a commercially available laser diffraction particle size distribution measuring apparatus.

  Specific examples of the particle size and size distribution measuring method will be shown.

  In a 100 ml beaker, 0.01 g of aliphatic carboxylic acid silver salt particle sample is taken, 0.1 g of nonion NS-210 (manufactured by NOF Corporation) and 40 ml of water are added, and then ultrasonic dispersion is performed at room temperature. The average particle size and standard deviation can be measured with the obtained dispersion using a laser diffraction particle size analyzer SALD-2000 (manufactured by Shimadzu Corporation).

  In order to prepare the non-photosensitive aliphatic carboxylic acid silver salt so that the average sphere equivalent diameter is 0.05 μm or more and 0.5 μm or less and the standard deviation of the sphere equivalent diameter is 0.3 or less, It is preferable to prepare by reacting by the mixing method shown.

  The aliphatic carboxylic acid silver salt particles in the present invention are preferably prepared by reacting a solution containing silver ions with an aliphatic carboxylic acid alkali metal salt solution or suspension. The solution containing silver ions is preferably an aqueous silver nitrate solution, the aliphatic carboxylic acid metal salt solution or suspension is an aqueous solution or an aqueous dispersion, and the addition and mixing are preferably performed simultaneously. Any method such as a method of adding to the liquid level of the bath or a method of adding to the liquid may be used, but a method of adding and mixing in the transfer means is preferred. Mixing in the transfer means means line mixing, and before the mixture of the solution containing silver ions and the aliphatic metal carboxylic acid alkali metal salt solution or suspension enters the batch storing the mixture containing the reactants. It is performed. As the stirring means in the mixing section, any means such as mechanical stirring such as a homomixer, static mixer, turbulent flow effect or the like may be used, but it is preferable not to use mechanical stirring. In addition, the mixing in the transfer means includes a solution containing silver ions, an alkali metal salt of an aliphatic carboxylic acid salt or a suspension, water, a circulated liquid of a mixed liquid stored in a batch after mixing, and the like. Liquids or suspensions may be mixed.

  In the present invention, the concentration of the aqueous silver nitrate solution is preferably 1 to 15% by mass, and the concentration of the aliphatic carboxylic acid metal salt aqueous solution or the aqueous dispersion is preferably in the range of 1 to 5% by mass. Outside the above concentration range, productivity is significantly deteriorated in the low concentration region, which is not realistic, and in the high concentration region, it is difficult to adjust the particle size and size distribution within the range of the present invention. Further, the mixing molar ratio of silver nitrate to the aliphatic carboxylic acid alkali metal salt is preferably in the range of 0.9 to 1.1, and outside the range, the particle size and size distribution can be adjusted within the range of the present invention. In addition to difficulty, it tends to lead to a decrease in the yield of the aliphatic carboxylic acid silver salt and generation of silver oxide that causes fogging.

  In the present invention, the prepared aliphatic carboxylic acid silver salt is preferably washed with water and then dried from the viewpoint of storage stability. Washing with water is performed mainly for the purpose of removing unreacted ions, but it may be performed with an organic solvent in consideration of the subsequent drying step. The washing with water is preferably performed at 50 ° C. or lower. Furthermore, it is preferable to carry out at 30 degrees C or less. When carried out at 50 ° C. or higher, it becomes difficult to adjust the particle size and size distribution within the scope of the present invention. Moreover, it is preferable to perform drying at or below the phase transition temperature of the aliphatic carboxylic acid silver salt. Furthermore, it is preferable to carry out at 50 degrees C or less, and it is preferable to carry out at low temperature as much as possible. Drying above the phase transition temperature makes it difficult to adjust the particle size and size distribution within the scope of the present invention.

  In the present invention, the aliphatic carboxylic acid silver salt is preferably prepared in the absence of photosensitive silver halide grains. In the preparation in the presence of light-sensitive silver halide, it is difficult to adjust the size and size distribution of the aliphatic carboxylic acid silver salt grains within the scope of the present invention because of compatibility with fogging performance.

The aliphatic carboxylic acid silver salt of the present invention can be used in a desired amount, but the total silver amount including the silver halide is preferably 0.8 to 1.5 g / m ^2, more preferably 1.0 to 1.3 g. / M ² is preferable.

(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.

[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 (made 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 (made 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 flat 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 present invention, the tabular aliphatic carboxylic acid silver salt particles are preferably preliminarily dispersed together with a binder or a surfactant as necessary, and then dispersed and pulverized 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 a preferable condition.

  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, 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, 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.

[Developer]
The present invention is characterized in that a silver salt photothermographic dry imaging material is processed with a heat developing machine which forms an image by heating at a desired developing temperature after imagewise exposure. In the present invention, the heat development temperature is preferably in the range of 110 to 150 ° C, and more preferably in the range of 115 to 135 ° C. If the heating temperature is less than 80 ° C., sufficient image density cannot be obtained in a short time, and if the heating temperature is high (particularly 200 ° C. or more), transfer to the roller due to melting of the binder, transportability, developing machine, etc. are also adversely affected. Effect. By heating, a silver image is generated by an oxidation-reduction reaction between an organic silver salt (which functions as an oxidizing agent) and a reducing agent. This reaction process proceeds without any supply of treatment liquid such as water from the outside.

  Any heating means may be used, such as contact heating with a heating drum or a heating plate, non-contact heating such as radiation, but contact heating with a heating plate is preferred. The contact heating surface may be on either the photosensitive layer side or the non-photosensitive layer side, but the non-photosensitive layer side is preferably the contact heating surface in terms of stability to the processing environment. The developing unit is preferably configured by combining a plurality of zones and a plurality of means that are independently temperature controlled, and further includes at least one heat retention zone that maintains a specific developing temperature. preferable. Therefore, in the thermal development apparatus that can be preferably used in the present invention, the thermal development process can adopt a separate configuration for the temperature raising portion and the heat retaining portion, and the heating means such as a heating member and the sheet film are in close contact with each other in the temperature raising portion. It prevents contact unevenness by preventing contact, and it is not necessary to make such close contact in the heat retaining part, and by using an optimal heating method that differs between the temperature rising part and the heat retaining part, high image quality without density unevenness can be achieved. It is possible to achieve a configuration that enables rapid processing of the thermal development process, downsizing of the apparatus, and cost reduction while maintaining.

  In the thermal development apparatus, the temperature raising unit heats the sheet film while pressing the sheet film against a plate heater by a counter roller, and the heat retaining unit is in a slit formed between guides having at least one heater. The sheet film can be heated. In the temperature raising section, the sheet heater is pressed against and contacted with the plate heater by the opposing roller, so that the plate heater and the sheet film can be brought into close contact with each other. Since it suffices to carry it while heating (keeping heat) between the slits, the driving parts of the carrying system are not necessary, and the size of the apparatus can be reduced and the cost can be reduced without requiring much accuracy of the slit dimensions.

  According to this heat development apparatus, in the first zone, the sheet film is heated by ensuring intimate contact between the heating means such as a heating member and the sheet film, and the occurrence of uneven density is suppressed. Since there is no need for contact, in the second zone, by keeping the sheet film warm in the guide gap, rapid processing of the thermal development process, miniaturization of the device and cost reduction are possible while maintaining high image quality without density unevenness. Can be configured. When the guide gap is 3 mm or less, there is little effect on the heat retaining performance regardless of the sheet film conveyance posture in the second zone, and the positioning accuracy between the fixed guide and another guide is not so required, and both guides are processed. The tolerance for time curvature error and mounting accuracy is increased, resulting in a significant increase in design freedom, which can contribute to a reduction in the cost of the apparatus.

  In the thermal development apparatus, it is preferable that a guide gap of the second zone is in a range of 1 to 3 mm. When the guide gap is 1 mm or more, the application surface of the photothermographic material of the sheet film is difficult to touch the guide surface and the possibility of scratches is reduced, which is preferable.

  Further, it is preferable that the fixed guide and the guide in the second zone have substantially the same curvature. When the curvature of the guide in the second zone is given to reduce the size of the apparatus, a guide with a substantially constant guide gap can be configured.

  In addition, it is possible to configure the engagement time with the sheet film in the temperature raising part and the heat retaining part to be 10 seconds or less, and it is possible to shorten the period of the temperature raising process and the heat retaining process and to quickly process the thermal development process. Is possible.

  In addition, a recess is provided between the temperature raising portion and the heat retaining portion, and the foreign material from the temperature raising portion is configured to enter the recess, so that the film tip is transferred while the temperature raising portion is conveyed. The foreign matter accumulated and moved by the portion can be prevented from being brought into the heat retaining portion, and jamming, scratches, uneven density, etc. can be prevented from occurring on the sheet film.

  The temperature raising part and the heat retaining part are preferably configured to heat the sheet film by opening the coated surface side of the photothermographic material. Also in the cooling section, it is preferable to perform cooling by opening the coated surface side of the photothermographic material.

  However, the mechanism of the heat retention zone may be a mechanism that maintains the heated film temperature, and is not limited to the above. The development time is preferably 5 to 10 seconds.

[Developer with preheat zone heated to 70 to 100 ° C. immediately before thermal development]
The present invention forms an image by processing a silver salt photothermographic dry imaging material with a heat developing machine having a preheat zone heated to 70 to 100 ° C. after the imagewise exposure and before the heat development step of heating at a desired development temperature. It is characterized by doing. Furthermore, it is preferable to process with the heat developing machine which has a preheat zone heated to 90-100 degreeC. Although there is no restriction | limiting in particular in the heating mechanism of a preheat zone, From a viewpoint of cost and controllability, contact heating with a heating plate is preferable. The heating temperature accuracy of the preheat zone is preferably ± 1 ° C., and more preferably ± 0.5 ° C. The heating time varies depending on the heating mechanism, but is preferably in the range of 0.5 to 7 seconds. Furthermore, it is preferably in the range of 1 to 3 seconds.

[Developer having a slow cooling zone in which development is stopped by adjusting the temperature to 10 to 20 ° C. lower than the thermal development temperature]
The present invention has a slow cooling zone in which a silver salt photothermographic dry imaging material is imagewise exposed, heated at a desired development temperature, and then adjusted to a temperature lower by 10 to 20 ° C. than the thermal development temperature to stop development. An image is formed by processing with a heat developing machine. Furthermore, it is preferable to process with a heat developing machine having a slow cooling zone in which the development is stopped by adjusting the temperature to 10 to 15 ° C. lower than the heat development temperature. The mechanism of the slow cooling zone is not particularly limited, but contact cooling with a plate adjusted to a desired temperature is preferable from the viewpoint of cost and controllability. The temperature accuracy of the slow cooling zone is preferably ± 1 ° C., more preferably ± 0.5 ° C. The slow cooling time is preferably x0.25 or more with respect to the development time, and is preferably in the range of x0.25 to x1.0 in view of rapid processing.

  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 device represented by a film tray, a laser image recording device, 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.

(Exposure of silver salt photothermographic dry imaging materials)
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 the laser preferably used in the photosensitive material of the present invention, a gas laser (Ar ion, Kr ion, He—Ne), YAG laser, dye laser, 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 exposed 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 distribution of the exposure wavelength 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. .

(Transportation of silver salt photothermographic dry imaging materials)
In the present invention, from the viewpoint of speeding up, it is necessary to correspond to an embodiment in which exposure processing and heat development processing are performed simultaneously. In order to perform the exposure process and the thermal development process at the same time, that is, to start development on a part of the sheet that has already been exposed while exposing a part of the sheet sensitive material, It is preferable that the distance between them is 0 cm or more and 50 cm or less, and this makes a series of processing time of exposure and development extremely short. 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.

  Hereinafter, the best mode of the heat development apparatus used in the present invention will be described with reference to the drawings.

<Preferred embodiment>
FIG. 1 is a side view schematically showing a main part of a heat development apparatus according to a preferred embodiment.

  As shown in FIG. 1, a heat development apparatus 40 according to a preferred embodiment includes an EC surface in which a photothermographic material is coated on one side of a sheet-like support substrate made of PET or the like as described above, and is opposite to the EC surface. A latent image is formed on the EC surface with the laser light L from the optical scanning exposure unit 55 while the film F having the BC surface on the side of the supporting substrate is sub-scanned and conveyed, and then the film F is heated from the BC surface side. The latent image is then developed to be visualized, conveyed to the upper part of the apparatus through a curved conveying path, and discharged.

  The heat development apparatus 40 in FIG. 1 picks up and conveys a film storage section 45 provided near the bottom of the apparatus housing 40a for storing a large number of unused films F, and the uppermost film F in the film storage section 45. A pickup roller 46 for conveying, a conveyance roller pair 47 for conveying the film F from the pickup roller 46, and a curved surface shape for guiding the film F from the conveyance roller pair 47 and conveying the film F in a substantially reversed direction. Laser light L is applied to the film F based on the image data between the curved surface guide 48, the conveyance roller pair 49a, 49b for sub-scanning conveyance of the film F from the curved surface guide 48, and the conveyance roller pair 49a, 49b. An optical scanning exposure unit 55 that forms a latent image on the EC surface by scanning and exposing.

  The thermal developing device 40 further heats the film F on which the latent image is formed from the BC surface side to raise the temperature to a predetermined heat development temperature, and heats the heated film F to a predetermined temperature. A heat retaining section 53 that retains the heat development temperature, a cooling section 54 that cools the heated film F from the BC surface side, a densitometer 56 that is disposed on the outlet side of the cooling section 54 and measures the density of the film F, A transport roller pair 57 that discharges the film F from the densitometer 56, and a film mounting portion that is provided on the upper surface of the apparatus housing 40a so that the film F discharged by the transport roller pair 57 is mounted. 58.

  As shown in FIG. 1, in the thermal development device 40, upward from the bottom of the apparatus housing 40 a, the film storage unit 45, the substrate unit 59, the conveyance roller pairs 49 a and 49 b, the temperature raising unit 50, and the heat retaining unit 53 (upstream). The film storage portion 45 is at the lowermost position, and the substrate portion 59 is provided between the temperature raising portion 50 and the heat retaining portion 53, so that it is not easily affected by heat.

  Further, since the conveyance path from the pair of conveyance rollers 49a and 49b for the sub-scan conveyance to the temperature raising unit 50 is configured to be relatively short, the front end of the film F is exposed while the light F is exposed to the film F by the optical scanning exposure unit 55. On the side, heat development heating is performed by the temperature raising unit 50 and the heat retaining unit 53.

  The temperature raising part 50 and the heat retaining part 53 constitute a heating part, and the film F is heated to the heat development temperature and maintained at the heat development temperature. The temperature raising unit 50 includes a first heating zone 51 that heats the film F on the upstream side, and a second heating zone 52 that heats the film F on the downstream side.

  The first heating zone 51 includes a planar heating guide 51b made of a metal material such as aluminum and fixed, a planar heating heater 51c made of a silicon rubber heater or the like in close contact with the back surface of the heating guide 51b, A plurality of opposing rollers 51a made of silicon rubber or the like, which is arranged so as to maintain a gap narrower than the film thickness so that the film can be pressed against the fixed guide surface 51d of the guide 51b and whose surface is thermally insulating compared to metal or the like; Have

  The second heating zone 52 includes a planar heating guide 52b made of a metal material such as aluminum and fixed, a planar heating heater 52c made of a silicon rubber heater or the like in close contact with the back surface of the heating guide 52b, A plurality of opposing rollers 52a made of silicon rubber or the like, which is arranged to maintain a gap narrower than the film thickness so that the film can be pressed against the fixed guide surface 52d of the guide 52b, and whose surface is more thermally insulating than metal or the like; Have

  The heat retaining section 53 is configured on a heating guide 53b made of a metal material such as aluminum and fixed, a planar heating heater 53c made of a silicon rubber heater or the like in close contact with the back surface of the heating guide 53b, and a surface of the heating guide 53b. And a guide part 53a made of a heat insulating material or the like disposed so as to face the fixed guide surface 53d so as to have a predetermined gap (slit) d. The heat retaining unit 53 is configured in a planar manner on the temperature raising unit 50 side continuously with the second heating zone 52, and is configured in a curved surface with a predetermined curvature from the middle toward the upper part of the apparatus.

  In the first heating zone 51 of the temperature raising unit 50, the film F conveyed by the conveying roller pairs 49a and 49b from the upstream side of the temperature raising unit 50 is pressed against the fixed guide surface 51d by each counter roller 51a that is rotationally driven. As a result, the BC surface comes into close contact with the fixed guide surface 51d and is conveyed while being heated.

  Similarly, in the second heating zone 52, the BC surface is fixed to the fixed guide surface 51d by pressing the film F conveyed from the first heating zone 51 against the fixed guide surface 52d by each counter roller 52a that is rotationally driven. It is conveyed while being in close contact with and heated.

  Note that a concave portion opened in a V shape may be provided between the second heating zone 52 and the heat retaining portion 53 of the temperature raising unit 50, and foreign matter from the temperature raising unit 50 may be contained in the concave portion. It is possible to prevent foreign matter from the temperature raising unit 50 from being brought into the heat retaining unit 53 by dropping into the heat retaining unit 53.

  In the heat retaining portion 53, the film F conveyed from the second heating zone 52 is heated (heat retained) by the heat from the heating guide 53b in the gap d between the fixed guide surface 53d of the heating guide 53b and the guide portion 53a. However, it passes through the gap d by the conveying force of the opposing roller 52a on the second heating zone 52 side. At this time, the film F is conveyed while gradually changing the direction from the horizontal direction to the vertical direction in the gap d, and heads toward the cooling unit 54.

  In the cooling unit 54, the film F conveyed in the substantially vertical direction from the heat retaining unit 53 is cooled by being brought into contact with the cooling guide surface 54c of the cooling plate 54b made of a metal material or the like by the opposing roller 54a and cooling from the vertical direction. The direction of the film F is changed to the film mounting part 58 in the direction and conveyed. The cooling effect can be increased by making the cooling plate 54b a finned heat sink structure. A part of the cooling plate 54b may have a heat sink structure with fins.

  The cooled film F coming out of the cooling unit 54 is subjected to density measurement by a densitometer 56, conveyed by a conveying roller pair 57, and discharged to a film placement unit 58. The film placing unit 58 can temporarily place a plurality of films F.

  As described above, in the heat development apparatus 40 of FIG. 1, the film F has the BC surface facing the fixed guide surfaces 51d, 52d, 53d in the heated state in the temperature raising portion 50 and the heat retaining portion 53, and the photothermographic material. The coated EC surface is conveyed in an open state. In the cooling unit 54, the film F is conveyed with the BC surface contacting the cooling guide surface 54c and cooled, and the EC surface coated with the heat developing material is opened.

  Moreover, the film F is conveyed by the opposing rollers 51a and 52a so that the passage time of the temperature raising part 50 and the heat retaining part 53 is 10 seconds or less. Therefore, the heating time from temperature increase to heat retention is also 10 seconds or less.

  As described above, according to the heat development apparatus 40 of FIG. 1, in the temperature raising unit 50 that requires uniform heat transfer, the heating guides 51b and 52b and the plurality of opposed rollers that press the film F against the heating guides 51b and 52b. Since the film F is transported while ensuring contact heat transfer by bringing the film F into close contact with the fixed guide surfaces 51d and 52d by 51a and 52a, the entire surface of the film is heated uniformly and the temperature rises uniformly. Becomes a high-quality image with reduced density unevenness.

  Further, after the temperature is raised to the heat development temperature, the film is transported to the gap d between the fixed guide surface 53d of the heating guide 53b and the guide portion 53a by the heat retaining portion 53, and in particular without being brought into close contact with the fixed guide surface 53d. Even if heating is performed in the gap d (direct heat contact with the fixed guide surface 53d and / or heat transfer by contact with the surrounding high-temperature air), the film temperature is predetermined with respect to the developing temperature (for example, 123 ° C.). Within the range (for example, 0.5 ° C.). Thus, regardless of whether the film is conveyed along the wall surface of the heating guide 53b or the curved surface guide 53a in the gap d, the film temperature difference is less than 0.5 ° C., and a uniform heat retaining state can be maintained. There is almost no risk of density unevenness in the finished film. For this reason, since it is not necessary to provide drive parts, such as a roller, in the heat retention part 53, a score reduction can be achieved.

  Furthermore, since the heating time of the film F can be 10 seconds or less, a rapid heat development process can be realized, and the heat retaining portion 53 extending in the horizontal direction from the temperature raising portion 50 becomes a curved surface in the middle and extends in the vertical direction. Since the film F is discharged to the film mounting unit 58 with the direction of the film F being substantially reversed by the cooling unit 54, the cooling unit 54 has a predetermined curvature according to the apparatus layout. It is possible to cope with downsizing of the installation area and downsizing of the entire device.

  In conventional large machines, the film was heated to the development temperature and the heat-retaining function was sufficient for the part that had enough heat retention, and as a result, unnecessary heating materials were used. However, the increase in the number of parts and cost increases, and in the conventional small machines, it is difficult to guarantee heat transfer at the time of temperature rise. According to the preferred embodiment, both of the problems can be solved by separately performing the heat development process in the temperature raising unit 50 and the heat retaining unit 53.

  In addition, the film F is heated from the BC side with the temperature raising unit 50 and the heat retaining unit 53 with the EC surface coated with the photothermographic material open, so that the thermal development process can be performed in a rapid process of 10 seconds or less. When performing, since the solvent (moisture, organic solvent, etc.) contained in the film F to be heated and volatilized (evaporated) is dispersed at the shortest distance by opening the EC surface side, the heating time (volatilization time) is short. However, even if there is a part where the contact between the film F and the fixed guide surfaces 51d and 52d is partially poor, the thermal diffusion effect by the PET base on the BC surface causes a contact property. The temperature difference from the good portion is relaxed, and as a result, the density difference hardly occurs, so that the density can be stabilized and the image quality is stabilized. In general, considering the heating efficiency, the EC surface side heating was considered to be better. However, the thermal conductivity of PET of the support base of the film F was 0.17 W / m ° C., and the PET base thickness was 170 μm. Considering the fact that it is before and after, it is preferable that the time delay is slight and can be easily offset by increasing the heater capacity, etc., and the effect of reducing the contact unevenness can be expected.

  Further, the solvent (water, organic solvent, etc.) in the film F is going to volatilize (evaporate) while leaving the heat retaining part 53 and reaching the cooling part 54, but the cooling part 54 also has the film F Since the EC surface is in an open state, the solvent (water, organic solvent, etc.) is not trapped and is volatilized for a longer time, so that the image quality is more stable. Thus, the cooling time cannot be ignored during the rapid processing, and is particularly effective for the rapid processing with a heating time of 10 seconds or less.

(Photosensitive silver halide grains)
The photosensitive silver halide grains according to the present invention (hereinafter also referred to as photosensitive silver halide or silver halide) can inherently absorb light as an intrinsic property of silver halide crystals, or are artificial. In the silver halide crystal when visible light or infrared light can be absorbed by a physicochemical method, and light in any region within the light wavelength range from the ultraviolet light region to the infrared light region is absorbed. And / or silver halide crystal grains that have been processed so that physicochemical changes can occur on the crystal surface.

  The silver halide grains themselves according to the present invention can be prepared as a silver halide grain emulsion (also referred to as a silver halide emulsion) using a known method. That is, any of an acidic method, a neutral method, an ammonia method, etc. may be used, and a method of reacting a soluble silver salt and a soluble halogen salt may be any one of a one-side mixing method, a simultaneous mixing method, a combination thereof, and the like. Of these methods, the so-called controlled double jet method, in which silver halide grains are prepared while controlling the formation conditions, is preferred.

  Usually, silver halide seed grains are divided into two stages: grain nucleation and grain growth, and these may be performed continuously at a time, or nucleation (seed grain) formation and grain growth are performed separately. The method may be used. The controlled double jet method in which the particle formation is controlled by controlling the pAg, pH, etc., which are particle formation conditions, is preferable because the particle shape and size can be controlled. For example, when performing a method in which nucleation and particle growth are performed separately, first, an aqueous silver salt solution and an aqueous halide solution are uniformly and rapidly mixed in an aqueous gelatin solution to produce nuclei (seed particles) (nucleation process). Then, silver halide grains are prepared by a grain growth process in which grains are grown while supplying an aqueous silver salt solution and an aqueous halide solution under controlled pAg, pH, and the like. After the formation of grains, a desired silver halide emulsion can be obtained by removing unnecessary salts and the like by a desalting step by a known desalting method such as a noodle method, a flocculation method, an ultrafiltration method, or an electrodialysis method. .

  In the present invention, the grain size distribution of silver halide grains is preferably monodispersed. The term “monodispersed” as used herein means that the coefficient of variation of the particle diameter obtained by the following formula is 30% 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
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 average aspect ratio when using tabular silver halide grains is preferably 1.5 or more and 100 or less, more preferably 2 or more and 50 or less. These are described in US Pat. Nos. 5,264,337, 5,314,798 and 5,320,958, and the desired tabular grains can be easily obtained. . Further, grains having rounded corners of silver halide grains can be preferably used.

  There is no particular limitation on the crystal habit on the outer surface of the silver halide grain, but when using a sensitizing dye having crystal habit (plane) selectivity in the adsorption reaction of the sensitizing dye on the surface of the silver halide grain. It is preferable to use silver halide grains having a relatively high proportion of crystal habits adapted to the selectivity. For example, when using a sensitizing dye that is selectively adsorbed on the crystal face of the Miller index [100], the proportion of the [100] face on the outer surface of the silver halide grain is preferably high, and this ratio is 50 % Or more, more preferably 70% or more, and particularly preferably 80% or more. The ratio of the Miller index [100] plane is a T.K. based on the adsorption dependency of the [111] plane and the [100] plane in the adsorption of the sensitizing dye. Tani, J .; Imaging Sci. 29, 165 (1985).

  The silver halide grains used in the present invention are preferably prepared using low molecular weight gelatin having an average molecular weight of 50,000 or less at the time of forming the grains, and particularly preferably used at the time of nucleation of silver halide grains.

  In the present invention, the low molecular weight gelatin preferably has an average molecular weight of 50,000 or less, more preferably 2,000 to 40,000, and particularly preferably 5,000 to 25,000. The average molecular weight of gelatin can be measured by gel filtration chromatography. Low molecular weight gelatin can be hydrolyzed by adding gelatin-degrading enzyme to a commonly used gelatin aqueous solution with an average molecular weight of about 100,000, heating by adding acid or alkali, and heating under atmospheric pressure or pressure. Can be obtained by thermal decomposition, decomposition by ultrasonic irradiation, or a combination of these methods.

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

  As the silver halide grains used in the present invention, it is preferable to use a compound represented by the following general formula when forming the grains.

YO (CH ₂ CH ₂ O) _m (CH (CH ₃ ) CH ₂ O) _p (CH ₂ CH ₂ O) _n Y
In the formula, Y represents a hydrogen atom, —SO ₃ M, or —CO—B—COOM, and M represents an ammonium group substituted with a hydrogen atom, an alkali metal atom, an ammonium group, or an alkyl group having 5 or less carbon atoms. And B represents a chain or cyclic group forming an organic dibasic acid. m and n each represents 0 to 50, and p represents 1 to 100.

  The polyethylene oxide compound represented by the above general formula comprises a step of producing a gelatin aqueous solution, a step of adding a water-soluble halide and a water-soluble silver salt to the gelatin solution, and an emulsion. It has been preferably used as an antifoaming agent for significant foaming when the emulsion raw material is stirred or moved, such as a step of coating on a support. This is described in Japanese Patent Publication No. 44-9497. The polyethylene oxide compound represented by the above general formula also functions as an antifoaming agent during nucleation. The compound represented by the above general formula is preferably used at 1% by mass or less, more preferably 0.01 to 0.1% by mass with respect to silver.

  The polyethylene oxide compound represented by the above general formula may be present at the time of nucleation and is preferably added in advance to the dispersion medium before nucleation, but may be added during nucleation or You may add and use for the silver salt aqueous solution and halide aqueous solution which are used at the time of formation. Preferably, it is used by adding 0.01 to 2.0% by mass to the halide aqueous solution or both aqueous solutions. Further, the compound represented by the above general formula is preferably present for a time of at least 50% of the nucleation step, and more preferably for a time of 70% or more. The compound represented by the above general formula may be added as a powder or dissolved in a solvent such as methanol.

  The temperature at the time of nucleation is usually 5 to 60 ° C., preferably 15 to 50 ° C. Even if the temperature is constant, the temperature rising pattern (for example, the temperature at the start of nucleation is 25 ° C. It is preferable to control the temperature within the above temperature range even when the temperature is gradually increased and the temperature at the end of nucleation is 40 ° C.) and vice versa.

The concentration of the aqueous silver salt solution and aqueous halide solution used for nucleation is preferably 3.5 mol / L or less, and more preferably used in a low concentration range of 0.01 to 2.5 mol / L. The addition rate of silver ions during nucleation is preferably 1.5 × 10 ^{−3 to} 3.0 × 10 ⁻¹ mol / min, more preferably 3.0 × 10 ^{−3 to} 8.0, per liter of the reaction solution. × 10 ^-2 mol / min.

  The pH at the time of nucleation can usually be set in the range of 1.7 to 10, but the pH on the alkali side broadens the particle size distribution of the nuclei to be formed, and is preferably pH 2 to 6. Moreover, pBr at the time of nucleation is 0.05-3.0 normally, Preferably it is 1.0-2.5, More preferably, it is 1.5-2.0.

  In the present invention, the average grain size of the silver halide grains is usually 10 to 50 nm, preferably 10 to 40 nm, and more preferably 10 to 35 nm. If the average grain size of the silver halide grains is smaller than 10 nm, the image density decreases, or the light irradiation image storage stability (the image obtained by heat development is used for diagnosis in a bright room or stored in a bright room) Storage stability) may be deteriorated. On the other hand, if it exceeds 50 nm, the image density may decrease.

  The average grain diameter referred to here is the length of the edge of the silver halide grains when the silver halide grains contained in the silver halide grain emulsion are cubic or octahedral so-called normal crystals. To tell. Further, when the silver halide grain is a tabular grain, it means the diameter when converted into a circular image having the same area as the projected area of the main surface. In addition, when it is not a normal crystal, for example, in the case of spherical particles, rod-shaped particles, etc., the diameter when considering a sphere equivalent to the volume of the silver halide grains is calculated as the particle size. The measurement was performed using an electron micrograph, and the average particle size was determined by averaging the measured values of the particle size of 300 particles.

  In the present invention, the gradation of the image density can be adjusted by using silver halide grains having an average particle diameter of 55 to 100 nm and silver halide grains having an average particle diameter of 10 to 50 nm in combination. In addition, the image density can be improved, and the decrease in image density over time can be improved (smaller). The ratio (mass ratio) of silver halide grains having an average particle diameter of 10 to 50 nm and silver halide grains having an average particle diameter of 55 to 100 nm is preferably 95: 5 to 50:50, more preferably 90. : 10-60: 40.

  As described above, when two types of silver halide grain emulsions having an average particle diameter are used, the two types of silver halide emulsions may be mixed and contained in the photosensitive layer. In order to adjust the gradation, it is also preferable that the photosensitive layer is composed of two or more layers, and the silver halide grain emulsions having the two average grain sizes are separately contained in each layer.

(Silver halide grains having a silver iodide content of 5 mol% to 100 mol%)
As the silver halide grains according to the present invention, silver halide grains containing silver iodide can be preferably used. As the halogen composition, the silver iodide content is preferably 5 mol% or more and 100 mol% or less. More preferably, they are 40 mol% or more and 100 mol% or less, More preferably, they are 70 mol% or more and 100 mol% or less, Especially preferably, they are 90 mol% or more and 100 mol% or less. If the silver iodide content is in this range, the intra-grain halogen composition distribution may be uniform, may be changed stepwise, or may be continuously changed. Further, silver halide grains having a core / shell structure with a high silver iodide content inside and / or on the surface can also be preferably used. A preferable structure is a 2- to 5-fold structure, more preferably 2- to 4-fold core / shell particles.

  Examples of the method for introducing silver iodide into the silver halide grains according to the present invention include a method of adding an alkali iodide aqueous solution during grain formation, fine grain silver iodide, fine grain silver iodobromide, fine grain silver iodochloride, fine grain iodine. A method of adding at least one fine particle of silver chlorobromide and a method using an iodide ion releasing agent described in JP-A-5-323487 and JP-A-6-11780 are preferred.

  The silver halide grains according to the present invention preferably exhibit direct transition absorption derived from the silver iodide crystal structure at a wavelength between 350 nm and 440 nm. Whether these silver halides have light absorption of direct transition can be easily distinguished by the fact that exciton absorption due to direct transition is observed in the vicinity of 400 nm to 430 nm.

(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.

  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. Are also included in the present invention. 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, although it may be adjusted by adjusting the conditions such as pH as described above or not 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.

  When manufacturing a comb type polymer, various methods can be used, but it is desirable to use a monomer capable of introducing a side chain having a molecular weight of 200 or more into a comb part (side chain). In particular, it is preferable to use a polyoxyalkylene group-containing ethylenically unsaturated monomer such as ethylene oxide or propylene oxide.

  As the polyoxyalkylene group-containing ethylenically unsaturated monomer, those having a polyoxyalkylene group represented by the following general formula are particularly preferable.

-(EO) k- (PO) m- (TO) n-R
(Here, E represents an ethylene group, P represents a propylene group, T represents a butylene group, and R represents a substituent. Examples of the butylene group include a tetramethylene group, an isobutylene group, etc. k is 1 to 300. In which m is an integer from 0 to 60 and n is an integer from 0 to 40. Preferably k is from 1 to 200, m is from 0 to 30, and n is from 0 to 20. However, k + m + n ≧ 2 Only one type of polyoxyalkylene group-containing ethylenically unsaturated monomer may be used, or two or more types may be used simultaneously.

  The substituent represented by R represents an alkyl group, an aryl group, a heterocyclic group, etc., and the alkyl group is methyl, ethyl, propyl, butyl, hexyl, octyl. Examples of dodecyl groups include aryl groups such as phenyl and naphthyl groups, and examples of heterocyclic groups include thienyl and pyridyl groups. In addition, these groups are further halogen atoms, alkoxy groups (methoxy group, ethoxy group, butoxy group, etc.), alkylthio groups (methylthio group, butylthio group, etc.), acyl groups (acetyl group, benzoyl group, etc.), alkaneamide groups ( An acetamide group, a propionamide group, etc.), an arylamide group (benzoylamide group, etc.) and the like may be further substituted. Further, these substituents may be further substituted with these groups.

  The polyoxyalkylene group represented by the general formula can be introduced into the polymer by using an ethylenically unsaturated monomer having these polyoxyalkylene groups. Examples of ethylenically unsaturated monomers having these groups include (polyoxyalkylene) acrylates and methacrylates, and (polyoxyalkylene) acrylates and methacrylates are commercially available hydroxy poly (oxyalkylene) materials such as commercial products. The names “Pluronic” (Pluronic (Asahi Denka Kogyo Co., Ltd.)), Adeka Polyether (Asahi Denka Kogyo Co., Ltd.), Carbowax [Carbowax (Glico Products)], Triton [Toriton (Rohm and Haas) (From Rohm and Haas))] and P.I. E. What is marketed as G (made by Daiichi Kogyo Seiyaku Co., Ltd.) can be manufactured by making it react with acrylic acid, methacrylic acid, acrylic chloride, methacrylic chloride, acrylic anhydride, etc. by a well-known method. Separately, poly (oxyalkylene) diacrylate produced by a known method can also be used.

  Moreover, as a monomer of a commercial item, it is Blemmer PE-90, Blemmer PE-200, Blemmer PE-350, Blemmer AE-90, Blemmer AE-, as a hydroxyl-terminated polyalkylene glycol mono (meth) acrylate manufactured by NOF Corporation. 200, Blemmer AE-400, Blemmer PP-1000, Blemmer PP-500, Blemmer PP-800, Blemmer AP-150, Blemmer AP-400, Blemmer AP-550, Blemmer AP-800, Blemmer 50 PEP-300, Blemmer 70 PEP- 350B, Blemmer AEP series, Blemmer 55PET-400, Blemmer 30PET-800, Blemmer 55PET-800, Blemmer AET series, Blemmer 30PPT-800, Blemma 50PPT-800, Blemmer 70PPT-800, Blemmer APT series, Brenmer 10PPB-500B, such as Brenmer 10APB-500B and the like. Similarly, as the alkyl terminal polyalkylene glycol mono (meth) acrylate manufactured by NOF Corporation, Blemmer PME-100, Blemmer PME-200, Blemmer PME-400, Blemmer PME-1000, Blemmer PME-4000, Blemmer AME-400, Blemmer 50POEP-800B, Blemmer 50AOEP-800B, Blemmer PLE-200, Blemmer ALE-200, Blemmer ALE-800, Blemmer PSE-400, Blemmer PSE-1300, Blemmer ASE series, Blemmer PKEP series, Blemmer AKEP series, Blemmer AE- 300, Blemmer ANE-1300, Blemmer PNEP series, Blemmer PNPE series, Blemmer 43ANEP 500, Bremer 70ANEP-550, etc., and Kyoeisha Chemical Co., Ltd. light ester MC, light ester 130MA, light ester 041MA, light acrylate BO-A, light acrylate EC-A, light acrylate MTG-A, light acrylate 130A, light Examples include acrylate DPM-A, light acrylate P-200A, light acrylate NP-4EA, and light acrylate NP-8EA.

  As the polymer according to the present invention, a graft polymer using a so-called macromer can also be used. For example, it is described in “New Polymer Experimental Science 2, Polymer Synthesis / Reaction” edited by Polymer Society, Kyoritsu Publishing Co., Ltd. 1995. It is also described in detail in Yuya Yamashita's “Chemical Monomer Chemistry and Industry” IPC, 1989. Among the macromers, the useful molecular weight is in the range of 10,000 to 100,000, the preferred range is 10,000 to 50,000, and the particularly preferred range is in the range of 10,000 to 20,000. When the molecular weight is 10,000 or less, the effect cannot be exhibited, and when it is 100,000 or more, the polymerizability with the copolymerization monomer forming the main chain is deteriorated. Specifically, Toagosei Co., Ltd. AA-6, AS-6S, AN-6S etc. can be used.

  Needless to say, the present invention is not limited to the above specific examples. Only one type of polyoxyalkylene group-containing ethylenically unsaturated monomer may be used, or two or more types may be used simultaneously.

  Other monomers specifically reacted with the above monomers include acrylic acid esters, methacrylic acid esters, acrylamides, methacrylamides, allyl esters, allyloxyethanols, vinyl ethers, vinyl esters, itaconic acid Examples thereof include dialkyl, dialkyl esters of fumaric acid or monoalkyl esters, crotonic acid, itaconic acid, acrylonitrile, methacrylonitrile, maleilonitrile, styrene and the like. Specific examples include the following compounds.

Acrylic acid esters: methyl acrylate, ethyl acrylate, propyl acrylate, chloroethyl acrylate, 2-hydroxyethyl acrylate, trimethylolpropane monoacrylate, benzyl acrylate, methoxybenzyl acrylate, furfuryl acrylate, tetrahydrofurfuryl acrylate, etc.
Methacrylic acid esters: methyl methacrylate, ethyl methacrylate, propyl methacrylate, chloroethyl methacrylate, 2-hydroxyethyl methacrylate, trimethylolpropane monomethacrylate, benzyl methacrylate, methoxybenzyl methacrylate, furfuryl methacrylate, tetrahydrofurfuryl methacrylate, etc.
Acrylamides: acrylamide, N-alkylacrylamide (the alkyl group has 1 to 3 carbon atoms, such as methyl, ethyl, propyl), N, N-dialkylacrylamide, N-hydroxyethyl-N-methylacrylamide, N-2-acetamidoethyl-N-acetylacrylamide and the like. In addition, as alkyloxyacrylamide, methoxymethylacrylamide, butoxymethylacrylamide, etc.
Methacrylamides: methacrylamide, N-alkylmethacrylamide, N-hydroxyethyl-N-methylmethacrylamide, N-2-acetamidoethyl-N-acetylmethacrylamide, methoxymethylmethacrylamide, butoxymethylmethacrylamide, etc.
Allyl compounds: allyl esters (eg, allyl acetate, allyl caproate, allyl caprylate, allyl laurate, allyl palmitate, allyl stearate, allyl benzoate, allyl acetoacetate, allyl lactate, etc.), allyloxyethanol, etc.
Vinyl ethers: alkyl vinyl ethers (eg, hexyl vinyl ether, octyl vinyl ether, decyl vinyl ether, ethyl hexyl vinyl ether, methoxyethyl vinyl ether, ethoxyethyl vinyl ether, chloroethyl vinyl ether, 1-methyl-2,2-dimethylpropyl vinyl ether, 2-ethylbutyl vinyl ether, hydroxy Ethyl vinyl ether, diethylene glycol vinyl ether, dimethylaminoethyl vinyl ether, diethylaminoethyl vinyl ether, butylaminoethyl vinyl ether, benzyl vinyl ether, tetrahydrofurfuryl vinyl ether, etc.)
Vinyl esters: vinyl butyrate, vinyl isobutyrate, vinyl trimethyl acetate, vinyl diethyl acetate, vinyl valate, vinyl caproate, vinyl chloroacetate, vinyl dichloroacetate, vinyl methoxyacetate, vinyl butoxyacetate, vinyl lactate, vinyl -Β-phenylbutyrate, vinylcyclohexylcarboxylate, etc.
Dialkyl itaconates: dimethyl itaconate, diethyl itaconate, dibutyl itaconate, etc. Dialkyl esters of fumaric acid or monoalkyl esters: dibutyl fumarate and the like, crotonic acid, itaconic acid, acrylonitrile, methacrylonitrile, maleilonitrile, styrene and the like.

  When introducing an amide group, a C4-C22 linear or branched alkyl group, an aromatic group, or a heterocyclic group having 5 or more members, these functional groups are contained in the above monomers or other monomers. The monomer to be selected may be selected. For example, 1-vinylimidazole or a derivative thereof can be used to introduce a heterocyclic group having 5 or more members. Furthermore, an isocyanate or epoxy group is introduced into the polymer in advance, and these are reacted with an alcohol or amine containing a linear or branched alkyl group, an aromatic group, or a 5- or more-membered heterocyclic group. Thus, various functional groups may be introduced into the polymer. In order to introduce isocyanate or epoxy, Karenz MOI (manufactured by Showa Denko KK) or Blemmer G (manufactured by Nippon Oil & Fats Co., Ltd.) can be used. It is also preferable to introduce a urethane bond.

  As the polymerization initiator, an azo polymer polymerization initiator or an organic peroxide can be used. As the azo polymer polymerization initiator, ABN-R 2,2′-azobisisobutyronitrile, ABN-V 2,2′-azobis (2,4-dimethylvaleronitrile) manufactured by Nippon Hydrazine Kogyo Co., Ltd. ABN-E 2,2'-azobis (2-methylbutyronitrile) and the like. Organic peroxides include bezoyl peroxide, dimethyl ethyl ketone peroxide, lauryl peroxide, Pertetra A, Perhexa HC, Perhexa TMH, Perhexa C, Perhexa V, Perhexa 22, Perhexa MC, Perbutyl H, manufactured by NOF Corporation. , Parkmill H, Parkmill P, Permenter H, Perocta H, Perbutyl C, Perbutyl D, Perhexyl D, Parroyl IB, Parroyl 355, Parroyl L, Parroyl S, Parroyl SA, Nipper BW, Nipper BMT-K40, Nipper BMT-T40, Niper BMT-M, Parroyl IPP, Parroyl NPP, Parroyl TCP, Parroyl EEP, Parroyl MBP, Parroyl OPP, Parroyl SBP, Park Mill ND, Parocta ND, Persi ND, Perhexyl ND, Perbutyl ND, Perhexyl PV, Perhexa 250, Perocta O, Perhexyl O, Perbutyl O, Perbutyl IB, Perbutyl L, Perbutyl 355, Perhexyl I, Perbutyl I, Perbutyl E, Perhexa 25Z, Perhexa 25MT, Perbutyl A Perhexyl Z, perbutyl ZT, perbutyl Z and the like.

  Moreover, as a polymerization inhibitor of this invention, although a quinone type | system | group inhibitor is used, hydroquinone and p-methoxyphenol are mentioned. Seiko Chemical Co., Ltd. phenothiazine, methoquinone, non-flex alba, MH (methyl hydroquinone), TBH (tert-butyl hydroquinone), PBQ (p-benzoquinone), tolquinone, TBQ (tert-butyl-p-benzoquinone), 2, And 5-diphenyl-p-benzoquinone.

  The isoelectric point of the polymer according to the present invention is preferably pH 6 or less. If a polymer having a high isoelectric point is used, as will be described later, when the silver halide grains are desalted by the aggregation precipitation method, the decomposition of the silver halide grains is promoted and the photographic performance is adversely affected. . Further, when silver halide fine particles are dispersed in a solvent, it is difficult to disperse unless the pH is raised, which is not preferable from the viewpoint of fogging. The isoelectric point of the polymer can be measured, for example, by isoelectric focusing or by measuring the pH after passing a 1% aqueous solution through a mixed bed column of cation and anion exchange resin.

  Various acidic groups can be introduced to lower the isoelectric point of the polymer. Examples include carboxylic acid and sulfonic acid groups. For the introduction of carboxylic acid, monomers of acrylic acid and methacrylic acid can be used, and a polymer containing methyl methacrylate or the like can be obtained by partial hydrolysis. In order to introduce the sulfonic acid group, styrene sulfonic acid or 2-acrylamido-2-methylpropane sulfonic acid can be used as a monomer, or can be introduced after the preparation of the polymer by various sulfation techniques. In particular, when a carboxylic acid is used, the solubility in a solvent is relatively high in an unneutralized state, and the property can be changed to water-soluble by neutralization or semi-neutralization, which is particularly preferable. Neutralization can also be performed with sodium or potassium salts, and organic salts such as ammonia, monoethanolamine, diethanolamine, and triethanolamine may be used. Imidazoles, triazoles, and amidoamines can also be used.

  The polymerization can be carried out in the presence or absence of a solvent, but is preferably in the presence of a solvent from the viewpoint of workability. Preferred solvents include alcohols such as ethanol, isopropyl alcohol, n-butanol, iso-butanol, tert-butanol, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl amyl ketone, methyl acetate, ethyl acetate, Esters such as butyl acetate, methyl lactate, ethyl lactate, butyl lactate, methyl 2-oxypropionate, ethyl 2-oxypropionate, propyl 2-oxypropionate, butyl 2-oxypropionate, methyl 2-methoxypropionate , Monocarboxylic acid esters such as ethyl 2-methoxypropionate, propyl 2-methoxypropionate and butyl 2-methoxypropionate, polar solvents such as dimethylformamide, dimethyl sulfoxide and N-methylpyrrolidone Ethers such as methyl cellosolve, cellosolve, butyl cellosolve, butyl carbitol, ethyl cellosolve acetate, propylene glycols such as propylene glycol, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monobutyl ether acetate And esters thereof, halogen solvents such as 1,1,1-trichloroethane and chloroform, ethers such as tetrahydrofuran and dioxane, aromatics such as benzene, toluene and xylene, and further perfluorooctane and perfluorotri-n-butylamine Fluorinated inert liquids and the like.

  Depending on the polymerizability of each monomer, a dropping polymerization method in which a monomer and an initiator are added dropwise to a reaction vessel is also effective for obtaining a polymer having a uniform composition. By removing by column filtration, reprecipitation purification, solvent extraction, etc., unreacted monomers can be removed. Alternatively, low-boiling unreacted monomers can be removed by stripping.

  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
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 1 or more numbers.

  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.

  The average molecular weight of the pluronic-type nonionic surfactant represented by the general formula (NSA1) or (NSA2) is preferably about 500 to 30,000, more preferably about 1,000 to 20,000, respectively. As the pluronic type nonionic surfactant represented by the general formula (NSA1) or (NSA2), at least one of the oxyethylene groups in the whole molecule is preferably 50% by mass or less.

  Nonionic surfactants of this type include, for example, the trade names Pluronic P94 and Pluronic F68.

  In the present invention, the nonionic surfactant is used at a concentration of 0.5 to 2%, preferably 0.9 to 1.5%.

  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), etc.

  The photosensitive silver halide grains according to the present invention can be chemically sensitized. For example, a compound that releases chalcogens such as sulfur, selenium, and tellurium and a noble metal ion that releases noble metal ions such as gold ions by the methods described in JP-A Nos. 2001-249428 and 2001-249426. The formation of chemical sensitization centers (chemical sensitization nuclei) that can capture electrons or holes generated by photoexcitation of photosensitive silver halide grains or spectral sensitizing dyes on the grains. it can. 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.

  As a method for chemical sensitization, techniques according to various chemical sensitization techniques conventionally used in the production of conventional silver halide light-sensitive materials for wet processing can be used (reference: (1) T Edited by H. James “The Theory of the Photographic Process” 4th edition, Macmillan Publishing Co., Ltd., 1977, (2) The Japan Photographic Society, “Basics of Photographic Engineering (Silver Salt Photography), Corona, 1979) In particular, when the silver halide grain emulsion is previously chemically sensitized and then mixed with non-photosensitive organic silver salt grains, it can be chemically sensitized by a conventional method.

The amount of the chalcogen compound used as the organic sensitizer varies depending on the chalcogen compound used, silver halide grains, reaction environment for chemical sensitization, etc., but is 10 ⁻⁸ to 10 ⁻ per mol of silver halide. ² mol is preferred, more preferably 10 ⁻⁷ to 10 ⁻³ mol.

  The environmental conditions for chemical sensitization are not particularly limited, but in the presence of a compound capable of eliminating or reducing the size of silver chalcogenide or silver nuclei on the photosensitive silver halide grains. In particular, it may be preferable to perform chalcogen sensitization using an organic sensitizer containing a chalcogen atom in the presence of an oxidizing agent capable of oxidizing silver nuclei. The sensitizing conditions in this case are preferably 6 to 11 as pAg, more preferably 7 to 10, pH 4 to 10, more preferably 5 to 8, and the temperature increases at 30 ° C. or lower. It is preferable to give a feeling.

  In addition, chemical sensitization using these organic sensitizers is preferably performed in the presence of a heteroatom-containing compound having adsorptivity to spectral sensitizing dyes or silver halide grains. By performing chemical sensitization in the presence of a compound having adsorptivity to silver halide grains, dispersion of the chemical sensitization central core can be prevented, and high sensitivity and low fog can be achieved. Although the spectral sensitizing dye will be described later, preferred examples of the heteroatom-containing compound having adsorptivity to silver halide include nitrogen-containing heterocyclic compounds described in JP-A-3-24537. In the nitrogen-containing heterocyclic compound, examples of the heterocyclic ring include pyrazole ring, pyrimidine ring, 1,2,4-triazole ring, 1,2,3-triazole ring, 1,3,4-thiadiazole ring, 1,2 , 3-thiadiazole ring, 1,2,4-thiadiazole ring, 1,2,5-thiadiazole ring, 1,2,3,4-tetrazole ring, pyridazine ring, 1,2,3-triazine ring, these rings Can be mentioned, for example, a triazolotriazole ring, a diazaindene ring, a triazaindene ring, a pentaazaindene ring, and the like. A heterocyclic ring in which a monocyclic heterocyclic ring and an aromatic ring are condensed, for example, a phthalazine ring, a benzimidazole ring, an indazole ring, a benzthiazole ring, or the like can also be applied.

  Of these, an azaindene ring is preferable, and an azaindene compound having a hydroxyl group as a substituent, for example, a hydroxytriazaindene, tetrahydroxyazaindene, hydroxypentaazaindene compound, or the like is more preferable.

  The heterocyclic ring may have a substituent other than the hydroxyl group. Examples of the substituent include an alkyl group, a substituted alkyl group, an alkylthio group, an amino group, a hydroxyamino group, an alkylamino group, a dialkylamino group, an arylamino group, a carboxyl group, an alkoxycarbonyl group, a halogen atom, and a cyano group. You may have.

The amount of the heterocyclic compound added varies over a wide range depending on the size, composition, and other conditions of the silver halide grains, but the approximate amount is 10 ^-6 per mole of silver halide. It is in the range of ˜1 mol, preferably in the range of 10 ⁻⁴ to 10 ⁻¹ mol.

  The photosensitive silver halide according to the present invention can be subjected to noble metal sensitization using a compound that releases noble metal ions such as gold ions. For example, a chloroaurate or an organic gold compound can be used as a gold sensitizer. The gold sensitization technique disclosed in JP-A-11-194447 is useful as a reference.

  In addition to the above-described sensitization methods, reduction sensitization methods and the like can also be used. Examples of reduction sensitization shell-like compounds include ascorbic acid, thiourea dioxide, stannous chloride, hydrazine derivatives, A borane compound, a silane compound, a polyamine compound, or the like can be used. Further, reduction sensitization can be performed by ripening the emulsion while maintaining the pH at 7 or higher or the pAg at 8.3 or lower.

  In the present invention, the silver halide grains subjected to chemical sensitization may be formed in the presence of an aliphatic carboxylic acid silver salt, or in the absence of the organic silver salt, A mixture of the two may be used.

  In the present invention, when the surface of the photosensitive silver halide grain 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.

  The photosensitive silver halide in the present invention is preferably subjected to spectral sensitization by adsorbing a spectral sensitizing dye. As spectral sensitizing dyes, cyanine dyes, merocyanine dyes, complex cyanine dyes, complex merocyanine dyes, holopolar cyanine dyes, styryl dyes, hemicyanine dyes, oxonol dyes, hemioxonol dyes, and the like can be used. For example, JP-A-63-159841, JP-A-60-140335, JP-A-63-231437, JP-A-63-259651, JP-A-63-304242, JP-A-63-15245, US Pat. No. 4,639,414, No. 4,740,455, No. 4,741,966, No. 4,751,175, No. 4,835,096 can be used.

  Useful sensitizing dyes used in the present invention include, for example, Research Disclosure (hereinafter abbreviated as RD) 17643IV-A (December 1978 p.23), RD18431X (August 1978 p.437). It is described in the literature described or cited. In particular, it is preferable to use a sensitizing dye having a spectral sensitivity suitable for the spectral characteristics of the light sources of various laser imagers and scanners. For example, compounds described in JP-A Nos. 9-34078, 9-54409, and 9-80679 are preferably used.

  Useful cyanine dyes are, for example, cyanine dyes having basic nuclei such as thiazoline nucleus, oxazoline nucleus, pyrroline nucleus, pyridine nucleus, oxazole nucleus, thiazole nucleus, selenazole nucleus and imidazole nucleus. Useful merocyanine dyes are preferably acidic nuclei such as thiohydantoin nucleus, rhodanine nucleus, oxazolidinedione nucleus, thiazolinedione nucleus, barbituric acid nucleus, thiazolinone nucleus, malononitrile nucleus and pyrazolone nucleus in addition to the above basic nucleus. Including.

  In the present invention, a sensitizing dye having spectral sensitivity particularly in the infrared can also be used. Examples of infrared spectral sensitizing dyes preferably used include infrared spectral sensitization disclosed in US Pat. Nos. 4,536,473, 4,515,888, 4,959,294, and the like. Examples include dyes.

  The silver salt photothermographic dry imaging material of the present invention is represented by the following general formula (SD1) and the following general formula (SD2) as described in JP-A No. 2004-309758. It is preferable to select and contain at least one of sensitizing dyes.

In the formula, Y ₁ and Y ₂ each represent an oxygen atom, a sulfur atom, a selenium atom, or a —CH═CH— group, and L _{1 to} L ₉ each represent a methine group. R ¹ and R ² each represents an aliphatic group. R ³ and R ⁴ each represent a lower alkyl group, a cycloalkyl group, an alkenyl group, an aralkyl group, an aryl group, or a heterocyclic group. W ₁ , W ₂ , W ₃ , and W ₄ are each a hydrogen atom, a substituent, or a nonmetallic atom necessary for bonding between W ₁ and W ₂ , W ₃ and W ₄ to form a condensed ring. Represents a group. Alternatively, R ³ and W ₁ , R ³ and W ₂ , R ⁴ and W ₃ , R ⁴ and W ₄ are bonded together to form a 5-membered or 6-membered non-metallic atomic group. To express. X ₁ represents an ion necessary for canceling the charge in the molecule, and k 1 represents the number of ions necessary for canceling the charge in the molecule. m1 represents 0 or 1. n1 and n2 each represents 0, 1 or 2. However, n1 and n2 are not 0 at the same time.

  The above-mentioned infrared sensitizing dyes are described in, for example, HM Hammer, The Chemistry of Heterocyclic Compounds, Vol. 18, The Cyanine Dies and Related Compounds, published by A. Weissberger ed. It can be easily synthesized by this method.

  These infrared sensitizing dyes may be added at any time after the silver halide is prepared. For example, silver halide grains or halogens may be added in a so-called solid dispersion state added to a solvent or dispersed in a fine particle form. It can be added to a light-sensitive emulsion containing silver halide grains / aliphatic carboxylic acid silver salt grains. Similarly to the heteroatom-containing compound having adsorptivity to the silver halide grains, chemical sensitization can be performed after adding and adsorbing to the silver halide grains prior to chemical sensitization. Thus, dispersion of the chemical sensitization central core can be prevented, and high sensitivity and low fog can be achieved.

  In the present invention, one kind of spectral sensitizing dye may be used alone, but as described above, it is preferable to use a combination of plural kinds of spectral sensitizing dyes. The combination is often used for the purpose of supersensitization and enlargement or adjustment of the photosensitive wavelength region.

  The emulsion containing the photosensitive silver halide and the aliphatic carboxylic acid silver salt used in the silver salt photothermographic dry imaging material of the present invention is not only a sensitizing dye but also a dye having no spectral sensitizing action itself or visible light. In the emulsion, a substance that does not substantially absorb the color and expresses a supersensitization effect may be contained 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. Examples of supersensitizers include heteroaromatic mercapto represented by the following. A compound or a mercapto derivative compound is preferred.

Ar-SM
In the formula, M is a hydrogen atom or an alkali metal atom, and Ar is an aromatic ring or condensed aromatic ring having one or more nitrogen, sulfur, oxygen, selenium, or tellurium atoms.

  Preferably, the heteroaromatic ring is benzimidazole, naphthimidazole, benzthiazole, naphthothiazole, benzoxazole, naphthoxazole, benzselenazole, benztelrazole, imidazole, oxazole, pyrazole, triazole, triazine, pyrimidine, pyridazine, pyrazine, pyridine , Purine, quinoline, or quinazoline. However, other heteroaromatic rings are also included.

  In addition, mercapto derivative compounds that substantially produce the above mercapto compounds when contained in a dispersion of an aliphatic carboxylic acid silver salt or silver halide grain emulsion are also included. In particular, mercapto derivative compounds represented below are preferred examples.

Ar-SS-Ar
Ar in the formula has the same meaning as in the case of the mercapto compound represented above.

  The heteroaromatic ring includes, for example, a halogen atom (for example, chlorine, bromine, iodine), a hydroxyl group, an amino group, a carboxyl group, and an alkyl group (for example, one or more carbon atoms, preferably 1 to 4 carbon atoms). It may have a substituent selected from the group consisting of those having a carbon atom) and alkoxy groups (for example, those having 1 or more carbon atoms, preferably 1 to 4 carbon atoms).

  In addition to the supersensitizer described above, macrocycles having heteroatoms disclosed in JP-A No. 2001-330918 can also be used as the supersensitizer.

  The supersensitizer according to the present invention is preferably used in an amount of 0.001 to 1.0 mol per mol of silver in a photosensitive layer containing an organic silver salt and silver halide grains. Particularly preferred is an amount of 0.01 to 0.5 mole per mole of silver.

  In the present invention, it is preferable that spectral sensitization is performed by adsorbing a spectral sensitizing dye on the surface of photosensitive silver halide grains, and that the spectral sensitization effect substantially disappears 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.

  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 (RD1).

  In the present invention, as a silver ion reducing agent, in particular, a compound in which at least one of the reducing agents is represented by the following general formula (RD1) is used alone or in combination with a reducing agent having another different chemical structure. preferable.

In the formula, 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 a hydrogen atom or a group that can be substituted on a benzene ring. R ₄ represents a substitutable group on the benzene ring, and m and n each represents an integer of 0 to 2.

Among the compounds represented by the general formula (RD1), a highly active reducing agent (hereinafter referred to as a compound of (RD1a)) in which at least one of R ₂ is a secondary or tertiary alkyl group is used. It is more preferable in that a photothermographic material having a high density and excellent light irradiation image storage stability can be obtained. In the present invention, it is preferable to use a compound of (RD1a) and a compound of the following general formula (RD2) in order to obtain a desirable color tone.

In the formula, X ₂ represents a chalcogen atom or CHR ₅ , and R ₅ represents a hydrogen atom, a halogen atom, an alkyl group, an alkenyl group, an aryl group or a heterocyclic group. R ₆ represents an alkyl group, which may be the same or different, but is not a secondary or tertiary alkyl group. R ₇ represents a hydrogen atom or a group that can be substituted on a benzene ring. R ₈ represents a substitutable group on the benzene ring, and m and n each represents an integer of 0 to 2.

  As the combined ratio, [the mass of the compound of (RD1a)]: [the mass of the compound of general formula (RD2)] is preferably 5:95 to 45:55, more preferably 10:90 to 40: 60.

In the general formula (RD1), X ₁ represents a chalcogen atom or CHR ₁ . The chalcogen atom is sulfur, selenium or tellurium, preferably a sulfur atom. R ₁ in CHR ₁ represents a hydrogen atom, a halogen atom, an alkyl group, an alkenyl group, an aryl group or a heterocyclic group. The halogen atom is a fluorine atom, a chlorine atom, a bromine atom or the like, and the alkyl group is preferably a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms. Specific examples include methyl, ethyl, propyl, butyl, and hexyl. Alkenyl groups such as vinyl, allyl, butenyl, hexenyl, hexadienyl, ethenyl-2-propenyl, 3-butenyl, 1-methyl-3-propenyl, 3-pentenyl, 1-methyl-3-butenyl, Examples of the aryl group include a benzene ring and a naphthalene ring, and examples of the heterocyclic group include thiophene, furan, imidazole, pyrazole, and pyrrole.

  These groups may further have a substituent. Specific examples of the substituent include a halogen atom (fluorine, chlorine, bromine, etc.), an alkyl group (methyl, ethyl, propyl, butyl, pentyl, i-pentyl). , 2-ethylhexyl, octyl, decyl, etc.), cycloalkyl groups (cyclohexyl, cycloheptyl, etc.), alkenyl groups (ethenyl-2-propenyl, 3-butenyl, 1-methyl-3-propenyl, 3-pentenyl, 1-methyl) -3-butenyl, etc.), cycloalkenyl groups (1-cycloalkenyl, 2-cycloalkenyl groups, etc.), alkynyl groups (ethynyl, 1-propynyl, etc.), alkoxy groups (methoxy, ethoxy, propoxy, etc.), alkylcarbonyloxy groups (Acetyloxy, etc.), alkylthio groups (methylthio, trifluoromethylthio, etc.), Sil group (acetyl group, benzoyl group), carboxyl group, alkylcarbonylamino group (acetylamino etc.), ureido group (methylaminocarbonylamino etc.), alkylsulfonylamino group (methanesulfonylamino etc.), alkylsulfonyl group (methanesulfonyl) , Trifluoromethanesulfonyl, etc.), carbamoyl group (carbamoyl, N, N-dimethylcarbamoyl, N-morpholinocarbonyl, etc.), sulfamoyl group (sulfamoyl, N, N-dimethylsulfamoyl, morpholinosulfamoyl etc.), trifluoromethyl Group, hydroxyl group, nitro group, cyano group, alkylsulfonamide group (methanesulfonamide, butanesulfonamide, etc.), alkylamino group (amino, N, N-dimethylamino, N, N-diethylamino) Etc.), sulfo group, phosphono group, sulfite group, sulfino group, alkylsulfonylaminocarbonyl group (methanesulfonylaminocarbonyl, ethanesulfonylaminocarbonyl etc.), alkylcarbonylaminosulfonyl group (acetamidesulfonyl, methoxyacetamidosulfonyl etc.), alkynyl Examples thereof include aminocarbonyl groups (acetamidocarbonyl, methoxyacetamidocarbonyl, etc.), alkylsulfinylaminocarbonyl groups (methanesulfinylaminocarbonyl, ethanesulfinylaminocarbonyl, etc.) and the like. Moreover, when there are two or more substituents, they may be the same or different. Particularly preferred substituents are alkyl groups.

R ₂ represents an alkyl group, which may be the same or different, but at least one is preferably a secondary or tertiary 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-amyl, 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) n} and (R _{4) m.} R ₂ is preferably a secondary or tertiary alkyl group, and preferably has 2 to 20 carbon atoms. A tertiary alkyl group is more preferable, t-butyl, t-amyl, t-pentyl and 1-methylcyclohexyl are more preferable, and t-butyl is most preferable.

R ₃ represents a hydrogen atom or a group that can be substituted on a benzene ring. Examples of groups that can be substituted on the benzene ring include halogen atoms such as fluorine, chlorine, bromine, alkyl groups, aryl groups, cycloalkyl groups, alkenyl groups, cycloalkenyl groups, alkynyl groups, amino groups, acyl groups, and acyloxy groups. , Acylamino group, sulfonylamino group, sulfamoyl group, carbamoyl group, alkylthio group, sulfonyl group, alkylsulfonyl group, sulfinyl group, cyano group, heterocyclic group and the like.

R ₃ is preferably methyl, ethyl, i-propyl, t-butyl, cyclohexyl, 1-methylcyclohexyl, 2-hydroxyethyl, 3-hydroxypropyl and the like. More preferred are methyl, 2-hydroxyethyl and 3-hydroxypropyl.

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 C 1-20 alkyl group having a hydroxyl group or a precursor group thereof (hereinafter also referred to as a precursor group), preferably a C 2-15 alkyl group having a hydroxyl group or a precursor group. is there. 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 group (p-toluenesulfonyloxy group, benzenesulfonyloxy group etc.), carbamoyloxy group (phenylcarbamoyloxy group etc.), thiocarbonyloxy group (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. The most preferred combination of R ₂ and R ₃ is that R ₂ is a tertiary alkyl group (t-butyl, t-amyl group, t-pentyl, 1-methylcyclohexyl, etc.), and R ₃ is a hydroxyl group or a precursor thereof. 1-C20 primary alkyl group having a 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-20 and R-58 to R-59 described in columns 6 to 16 of US Pat. No. 6,800,431.

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. n and m represent an integer of 0 to 2, and most preferably n and m are 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.

In general formula (RD2), R ₅ is the same group as R ₁ , R ₇ is the same group as R _3, and R ₈ is the same group as R ₄ . R ₆ represents an alkyl group, which may be the same or different, but is not a secondary or tertiary alkyl group. The alkyl group is preferably a substituted or unsubstituted one having 1 to 20 carbon atoms, and specific examples thereof include methyl, ethyl, propyl, butyl 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, sulfonamide group, sulfonyl group, phosphoryl group, acyl group, carbamoyl group , Ester groups, halogen atoms and the like.

R ₆ may form a saturated ring with (R ₈ ) _n and (R ₈ ) _m . R ₆ is preferably methyl. Among the compounds represented by the general formula (RD2), compounds preferably used are compounds satisfying the general formula (S) and the general formula (T) described in EP 1,278,101, Specific examples include compounds (1-24), (1-28) to (1-54), and (1-56) to (1-75) described in p21 to p28.

  Specific examples of the compounds represented by general formula (RD1) and general formula (RD2) are shown below, but the present invention is not limited to these.

  These bisphenol compounds represented by the general formula (RD1) and general formula (RD2) can be easily synthesized by a conventionally known method.

  In the present invention, examples of reducing agents that can be used in combination include US Pat. Nos. 3,770,448, 3,773,512, and 3,593,863, RD17029 and 29963, respectively. 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 (RD1) is preferably 1 × 10 ⁻² to 10 mol, particularly preferably 1 × 10 ^{−2 to} 1.5 mol, per mol of silver. It is.

  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 a result of further intensive studies on the silver salt photothermographic dry imaging material of the present invention, the horizontal axis is u ^* or a in the CIE 1976 (L ^* u ^* v ^* ) color space or (L ^* a ^* b ^* ) color space. ^{* When} plotting u ^* , v ^* or a ^* , b ^* at various photographic densities on a graph with the vertical axis representing v ^* or b ^* , a linear regression line is created. It was found that by adjusting the value to a specific range, it has a diagnostic ability equal to or higher than that of a conventional wet type silver salt photosensitive material. A preferable range of conditions is 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.

An example of a method for creating the above-described linear regression line, that is, a method for measuring u ^* , v ^*, a ^* , and b ^{* in} the CIE 1976 color space will be described next.

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 No. 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.

  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 the present invention, when a highly active reducing agent is used, the color tone (especially yellowishness) changes depending on the amount and ratio of use, or by using fine grain silver halide, the concentration is particularly 2.0. In order to prevent the image from being excessively reddish at the above high density portion, it is preferable to use a leuco dye that develops yellow and cyan colors and to adjust the amount of use.

  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 to 0.10.

(Yellow coloring 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. 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).

In the formula, 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 are 2-hydroxyphenylmethyl groups. There is nothing. 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.

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 (RD1). 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.

In the formula, 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 (RD1). 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 (RD1).

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 (RD1).

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 the substituents described in the description of R ₄ in formula (RD1).

  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 (RD1) and (RD2) of yellow coloring leuco dye is 0.001-0.2 by molar ratio, 0.005 More preferably, it is -0.1.

(Cyan coloring leuco dye)
The silver salt photothermographic dry imaging material of the present invention can also be adjusted in 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 increases when oxidized 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-I). The color image forming agent represented by the general formula (CLB-I) is particularly preferable in that it has high coloring 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-I) which are preferably used below will be described in detail.

In the formula, 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 linked to each other to form an aliphatic hydrocarbon ring, an aromatic hydrocarbon ring or a heterocyclic ring. A ₃ represents a —NHCO— group, a —CONH— group or a —NHCONH— group, and R ₃₃ represents a substituted or unsubstituted alkyl group, aryl group or heterocyclic group.

Moreover, -A ₃ -R ₃₃ may be a hydrogen atom. For example, the —A ₃ —R ₃₃ moiety represents a hydrogen atom, or A ₃ represents a —NHCO— group, a —CONH— group or a —NHCONH— group, and R ₃₃ represents a substituted or unsubstituted alkyl group. Represents an aryl 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 and the like, and examples of the alkenyl group include alkenyl groups having up to 20 carbon atoms (for example, vinyl, allyl, butenyl, hexenyl, hexadienyl, ethenyl-2- 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. As the alkenyl group, an alkenyl group 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, such as a phenyl group, a naphthyl group, a thienyl group, and the like. 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.

  Next, the compound represented by formula (CLB-I) will be described. The compound represented by the general formula (CLB-I) is preferably a compound represented by the following general formula (CLB-II) or (CLB-III), and most preferably a compound represented by (CLB-III). .

  First, the compound represented by formula (CLB-I) will be described.

In the formula, R ₄₁ , R ₄₂ , R _4a and R _4b each independently represent a hydrogen atom, an aliphatic group, an aromatic group, an alkoxy group, an aryloxy group, an acylamino group, a sulfonamide group, a carbamoyl group, or a halogen atom. . R ₄₃ represents a hydrogen atom, an aliphatic group, an aromatic group, an acyl group, an alkoxycarbonyl group, an aryloxycarboquinyl group, a carbamoyl group, a sulfamoyl group, or a sulfonyl group. X ₄₁ and X ₄₂ represent a substitutable group on the benzene ring. m41 and m42 represent an integer of 0 to 5. When there are a plurality of X ₄₁ and X ₄₂ , each X ₄₁ and X ₄₂ may be the same or different.

Specific examples of the aliphatic group represented by R ₄₁ , R ₄₂ , R _4a and R _4b 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 and the like. Examples of the cycloalkyl group include cyclohexyl and cyclopentyl 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 ₄₁ , R ₄₂ , R _4a and R _4b 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 ₄₁ , R ₄₂ , R _4a and R _4b include methoxy group, ethoxy group, isopropyloxy group, tert-butoxy group and the like.

Specific examples of the aryloxy group represented by R ₄₁ , R ₄₂ , R _4a and R _4b include a phenoxy group and a naphthyloxy group.

Examples of the acylamino group represented by R ₄₁ , R ₄₂ , R _4a and R _4b include an acetylamino group and a benzoylamino group.

Specific examples of the sulfonamide group represented by R ₄₁ , R ₄₂ , R _4a and R _4b include a methanesulfonamide group, a butanesulfonamide group, an octanesulfonamide group, a benzenesulfonamide group, and the like.

Examples of the carbamoyl group represented by R ₄₁ , R ₄₂ , R _4a and R _4b include an aminocarbonyl group, a methylaminocarbonyl group, a dimethylaminocarbonyl group, a propylaminocarbonyl group, a pentylaminocarbonyl group, and a cyclohexylaminocarbonyl group. , Phenylaminocarbonyl group, 2-pyridylaminocarbonyl group and the like.

Examples of the halogen atom represented by R ₄₁ , R ₄₂ , R _4a and R _4b are chlorine, bromine and iodine.

R ₄₁ and R ₄₂ 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.

R _4a and R _4b 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 ₄₃ include those of the aliphatic group, aromatic group, alkoxy group and aryloxy group represented by R ₄₁ and R ₄₂ . The example given as a specific example is given.

Specific examples of the acyl group represented by R ₄₃ include an acetyl group, a propionyl group, a butanoyl group, a hexanoyl group, a cyclohexanoyl group, a benzoyl group, and a pyridinoyl group.

Specific examples of the alkoxycarbonyl group represented by R ₄₃ include a methoxycarbonyl group, an ethoxycarbonyl group, and a tert-butoxycarbonyl group.

Specific examples of the aryloxycarboquinyl group represented by R ₄₃ include a phenoxycarbonyl group.

Examples of the carbamoyl group represented by R ₄₃ include an aminocarbonyl group, a methylaminocarbonyl group, a dimethylaminocarbonyl group, a propylaminocarbonyl group, a pentylaminocarbonyl group, a cyclohexylaminocarbonyl group, a phenylaminocarbonyl group, and 2-pyridylamino. A carbonyl group etc. are mentioned.

Examples of the sulfamoyl group represented by R ₄₃ include methylsulfamoyl, dimethylsulfamoyl, phenylsulfamoyl and the like.

Examples of the sulfonyl group represented by R ₄₃ include a methylsulfonyl group, a butylsulfonyl group, and an octylsulfonyl group.

R ₄₃ 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 ₄₁ and X ₄₂ include alkyl groups having 1 to 25 carbon atoms (methyl group, ethyl group, propyl group, isopropyl group, tert-butyl group, Pentyl group, hexyl group, cyclohexyl group, etc.), cycloalkyl group (cyclohexyl group, cyclopentyl group, etc.), alkenyl group (vinyl, allyl, butenyl, hexenyl, hexadienyl, ethenyl-2-propenyl, 3-butenyl, 1-methyl- 3-propenyl, 3-pentenyl, 1-methyl-3-butenyl, etc.), alkynyl group (ethynyl, propargyl group, etc.), glycidyl group, acrylate group, methacrylate group, aryl group (phenyl group etc.), aryl group (phenyl, Naphthyl group, etc.), heterocyclic group (pyridyl group, thiazolyl group, oxazolyl group, imida Ryl group, furyl group, pyrrolyl group, pyrazinyl group, pyrimidinyl group, pyridazinyl group, selenazolyl group, triphoranyl group, piperidinyl group, pyrazolyl group, tetrazolyl group, etc.), halogen atom (chlorine atom, bromine atom, iodine atom, fluorine atom, etc.) ), Alkoxy group (methoxy group, ethoxy group, propyloxy group, pentyloxy group, cyclopentyloxy group, hexyloxy group, cyclohexyloxy group, etc.), aryloxy group (phenoxy group, etc.), alkoxycarbonyl group (methyloxycarbonyl group) , Ethyloxycarbonyl group, butyloxycarbonyl group, etc.), aryloxycarbonyl group (phenyloxycarbonyl group, etc.), sulfonamide group (methanesulfonamide group, ethanesulfonamide group, butanesulfonamide group, hexane) Sulfonamide group, cyclohexanesulfonamide group, benzenesulfonamide group, etc.), sulfamoyl group (aminosulfonyl group, methylaminosulfonyl group, dimethylaminosulfonyl group, butylaminosulfonyl group, hexylaminosulfonyl group, cyclohexylaminosulfonyl group, phenylaminosulfonyl) Group, 2-pyridylaminosulfonyl group, etc.), urethane group (methylureido group, ethylureido group, pentylureido group, cyclohexylureido group, phenylureido group, 2-pyridylureido group, etc.), acyl group (acetyl group, propionyl group, Butanoyl group, hexanoyl group, cyclohexanoyl group, benzoyl group, pyridinoyl group, etc.), carbamoyl group (aminocarbonyl group, methylaminocarbonyl group, dimethylaminocarbonyl) Rubonyl group, propylaminocarbonyl group, pentylaminocarbonyl group, cyclohexylaminocarbonyl group, phenylaminocarbonyl group, 2-pyridylaminocarbonyl group, etc.), amide group (acetamide group, propionamide group, butanamide group, hexanamide group, benzamide group) Etc.), sulfonyl group (methylsulfonyl group, ethylsulfonyl group, butylsulfonyl group, cyclohexylsulfonyl group, phenylsulfonyl group, 2-pyridylsulfonyl group, etc.), sulfonamide group (for example, methylsulfonamide group, octylsulfonamide group, Phenylsulfonamide group, naphthylsulfonamide group, etc.), amino group (amino group, ethylamino group, dimethylamino group, butylamino group, cyclopentylamino group, anilino group, 2-pyri Arylamino group), a cyano group, a nitro group, a sulfo group, a carboxyl group, a hydroxyl group, can be exemplified Okizamoiru group. Further, these groups may be further substituted with these groups.

X ₄₁ and X ₄₂ are preferably an alkoxy group, an aryloxy group, a carbamoyl group, an amide group, a sulfonamide group, an amino group, more preferably an alkoxy group or an amino group.

  Next, among the compounds represented by the general formula (CLB-I), the compounds represented by the general formula (CLB-II) and the general formula (CLB-III) that are preferably used will be described.

Wherein, R _41, R _42, R ₄₃ are each synonymous with R _41, R _42, R ₄₃ in the general formula (CLB-I). X ₄₃ and X ₄₄ each represents an aliphatic group, an aromatic group, an amino group, an alkoxy group or an aryloxy group.

Examples of the aliphatic group, aromatic group, amino group, alkoxy group and aryloxy group represented by X ₄₃ and X ₄₄ are the aliphatic groups represented by X ₄₁ and X ₄₂ 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 ₄₃ and X ₄₄ are preferably an alkoxy group, an aryloxy group or an amino group, more preferably an alkoxy group or an amino group.

Wherein, R _41, R _42, R ₄₃ are each synonymous with R _41, R _42, R ₄₃ in the general formula (CLB-I). R ₄₄ , R ₄₅ , R ₄₆ and R ₄₇ each represent a hydrogen atom or an alkyl group.

Specific examples of the alkyl group represented by R ₄₄ , R ₄₅ , R ₄₆ and R ₄₇ include methyl, ethyl, propyl, i-propyl, t-butyl, pentyl, hexyl and the like. These groups may have a substituent at an arbitrary position, and examples of the substituent include the groups exemplified as the substituent in the general formula (CLB-I). R ₄₄ , R ₄₅ , R ₄₆ and R ₄₇ are preferably an alkyl group having 1 to 10 carbon atoms, more preferably methyl or ethyl.

  These compounds represented by the general formulas (CLB-I) to (CLB-III) can be easily synthesized by a conventionally known method such as 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 coloring leuco dye to the sum of the reducing agents represented by the general formulas (RD1) and (RD2) is preferably 0.001 to 0.2 in terms of molar ratio, and 0.005. More preferably, it is -0.1.

  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 (RD1). , Solution form, emulsified dispersion form, solid fine particle dispersion form, etc. may be contained in the coating solution by any method, and may be contained in the photosensitive material.

  The compounds of general formulas (RD1), (RD2), general formulas (YA), (YB) and cyan color-forming leuco dyes are preferably contained in a photosensitive layer (image forming layer) containing an organic silver salt. One may be contained in the photosensitive layer and 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)
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. Suitable binders are transparent or translucent and generally colorless. Yes, natural polymers, synthetic polymers, copolymers, and other media for forming a film, for example, those described in paragraph “0069” of JP-A No. 2001-330918 are exemplified.

  Of these, particularly preferred examples include methacrylic acid alkyl esters, methacrylic acid aryl esters, and styrenes. Among such polymer compounds, a polymer compound having an acetal group is preferably used. Even a polymer compound having an acetal group is more preferably a polyvinyl acetal having an acetoacetal structure, for example, U.S. Pat. Nos. 2,358,836, 3,003,879, 2,828,204, UK The polyvinyl acetal shown by patent 771,155 etc. can be mentioned.

  As the polymer compound having an acetal group, a compound represented by the general formula (V) described in “150” of JP-A No. 2002-287299 is particularly preferable.

  Preferred binders for the photosensitive layer according to the present invention are polyvinyl acetals, particularly preferably polyvinyl butyral, which is preferably used as the main binder. The main binder mentioned here means “a state in which the polymer occupies 50% by mass or more of the total binder of the photosensitive 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 polymer of the present invention is soluble. More preferably, a polyvinyl acetate, a polyacryl resin, a urethane resin, etc. are mentioned.

  The glass transition temperature (Tg) of the binder used in the present invention is preferably 70 to 105 ° C. in that a sufficient maximum density can be obtained in image formation.

  The binder of the present invention has a number average molecular weight of 1,000 to 1,000,000, preferably 10,000 to 500,000, and a degree of polymerization of about 50 to 1,000.

  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. If necessary, two or more binders may be used in combination as described above.

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 for holding at least the organic silver salt in the photosensitive layer (image forming layer), the ratio of the binder to the organic silver salt is preferably 15: 1 to 1: 2 (mass ratio), and particularly 8: A range of 1-1: 1 is preferred. That is, it is preferable that the binder amount of the photosensitive layer is a 1.5~6g / m ^2, more preferably from 1.7~5g / m ^2. If it is less than 1.5 g / m ² , the density of the unexposed area is significantly increased and may not be used.

  An organic gelling agent may be contained in the photosensitive layer. Incidentally, the organic gelling agent referred to here has a function of giving a yield value to the system by adding it to an organic liquid, such as polyhydric alcohols, and eliminating or reducing the fluidity of the system. The compound which has.

  The silver salt photothermographic dry imaging material of the present invention can also be produced through a production process using a coating solution for a photosensitive layer containing an aqueous dispersed polymer latex. In this case, a polymer latex in which 50% by mass or more of the total binder in the coating solution for the photosensitive layer is dispersed in water is preferable. Further, when a polymer latex is used in the preparation of the photosensitive layer, 50% by mass or more of the total binder in the photosensitive layer is preferably a polymer latex-derived polymer, and more preferably 70% by mass or more.

  Here, the polymer latex is a water-insoluble hydrophobic polymer dispersed as fine particles in a water-soluble dispersion medium. As the dispersion state, the polymer is emulsified in a dispersion medium, the emulsion is polymerized, the micelle is dispersed, or the polymer molecule has a partially hydrophilic structure, and the molecular chain itself is molecularly dispersed. Any of these may be used.

  The polymer latex that can be used in the silver salt photothermographic dry imaging material of the present invention may be a so-called core / shell type latex in addition to a normal uniform polymer latex. In this case, it may be preferable to change the Tg of the core and the shell.

  The minimum film-forming temperature (MFT) of the polymer latex according to the present invention is preferably -30 to 90 ° C, more preferably about 0 to 70 ° C. In addition, a film-forming auxiliary may be added to control the minimum film-forming temperature.

  Examples of the polymer species used for the polymer latex include acrylic resins, vinyl acetate resins, polyester resins, polyurethane resins, rubber resins, vinyl chloride resins, vinylidene chloride resins, polyolefin resins, and copolymers thereof. The polymer may be a linear polymer, a branched polymer, or a crosslinked polymer. The polymer may be a so-called homopolymer in which a single monomer is polymerized or a copolymer in which two or more monomers are polymerized. In the case of a copolymer, it may be a random copolymer or a block copolymer. The molecular weight of the polymer is a number average molecular weight and is usually about 5,000 to 1,000,000, preferably about 10,000 to 100,000. When the molecular weight is too small, the mechanical strength of the photosensitive layer is insufficient, and when the molecular weight is too large, the film forming property is poor and both are not preferable.

  The polymer latex preferably has an equilibrium water content of 0.01 to 2% by mass or less, more preferably 0.01 to 1% by mass at 25 ° C. and 60% RH (relative humidity). For the definition and measurement method of the equilibrium moisture content, for example, “Polymer Engineering Course 14, Polymer Material Testing Method (Edited by Polymer Society, Jinshokan)” can be referred to.

  Specific examples of the polymer latex include each latex described in “0173” of JP-A No. 2002-287299. These polymers may be used alone or as a blend of two or more as necessary. As a polymer seed | species of a polymer latex, what contains about 0.1-10 mass% of carboxylic acid components, such as an acrylate or a methacrylate component, is preferable.

  Furthermore, if necessary, a hydrophilic polymer such as gelatin, polyvinyl alcohol, methyl cellulose, hydroxypropyl cellulose, carboxymethyl cellulose, hydroxypropyl methyl cellulose or the like may be added within a range of 50% by mass or less of the total binder. The addition amount of these hydrophilic polymers is preferably 30% by mass or less based on the total binder of the photosensitive layer.

  Regarding the order of addition of the organic silver salt and the aqueous dispersed polymer latex in the preparation of the coating solution for the photosensitive layer, any of them may be added first or simultaneously, but preferably the polymer latex is used. Later.

(Crosslinking agent)
The photosensitive layer according to the present invention may contain a cross-linking agent capable of connecting the binders according to the present invention by cross-linking. By using a crosslinking agent for the binder, it is known that filming is improved and development unevenness is reduced, but there is also an effect of suppressing fogging during storage and suppressing generation of printout silver after development. is there.

  Examples of the crosslinking agent to be used include various crosslinking agents conventionally used for photographic light-sensitive materials, for example, aldehyde-based, epoxy-based, ethyleneimine-based, vinylsulfone-based, sulfone described in JP-A-50-96216. Acid ester-based, acryloyl-based, carbodiimide-based, and silane compound-based crosslinking agents are used, and the following isocyanate-based, silane compound-based, epoxy-based compounds, and acid anhydrides are preferable.

  Isocyanate-based crosslinking agents are isocyanates having at least two isocyanate groups and adducts thereof (adducts). More specifically, aliphatic diisocyanates, aliphatic diisocyanates having a cyclic group, benzene Diisocyanates, naphthalene diisocyanates, biphenyl isocyanates, diphenylmethane diisocyanates, triphenylmethane diisocyanates, triisocyanates, tetraisocyanates, adducts of these isocyanates and divalent or trivalent polyalcohols with these isocyanates Adducts and the like. As specific examples, isocyanate compounds described on pages 10 to 12 of JP-A-56-5535 can be used.

  In addition, the adduct of isocyanate and polyalcohol has particularly high ability to improve interlayer adhesion and prevent layer peeling, image shift and bubble generation. Such isocyanate may be placed in any part of the photothermographic material. For example, in the 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. It can be added to any layer and can be added to one or more of these layers.

  As the thioisocyanate-based crosslinking agent that can be used in the present invention, compounds having a thioisocyanate structure corresponding to the above-mentioned isocyanates are also useful.

  The amount of the crosslinking agent used is usually in the range of 0.001 to 2 mol, preferably 0.005 to 0.5 mol, with respect to 1 mol of silver.

  The isocyanate compound and thioisocyanate compound that can be contained in the present invention are preferably compounds that function as the above-mentioned crosslinking agent, but a good result can be obtained even if the compound has only one functional group.

  Examples of the silane compound include compounds represented by general formulas (1) to (3) disclosed in JP-A No. 2001-264930.

  Moreover, as an epoxy compound which can be used as a crosslinking agent, what is necessary is just to have one or more epoxy groups, and there is no restriction | limiting in the number of epoxy groups, molecular weight, and others. The epoxy group is preferably contained in the molecule as a glycidyl group via an ether bond or an imino bond. The epoxy compound may be any of a monomer, an oligomer, a polymer, etc., and the number of epoxy groups present in the molecule is usually about 1 to 10, preferably 2 to 4. When the epoxy compound is a polymer, it may be either a homopolymer or a copolymer, and the number average molecular weight Mn is particularly preferably in the range of about 2,000 to 20,000.

  The acid anhydride used in the present invention is a compound having at least one acid anhydride group represented by the following structural formula. The number of acid anhydride groups, molecular weight, and the like are not particularly limited as long as they have one or more acid anhydride groups.

-CO-O-CO-
Said epoxy compound and acid anhydride may use only 1 type, or may use 2 or more types together. The addition amount is not particularly limited, but is preferably in the range of 1 × 10 ⁻⁶ to 1 × 10 ⁻² mol / m ² , more preferably in the range of 1 × 10 ⁻⁵ to 1 × 10 ⁻³ mol / m ² . It is. This epoxy compound or acid anhydride can be added to any layer on the photosensitive layer side of the support, such as the photosensitive layer, surface protective layer, intermediate layer, antihalation layer, subbing layer, etc., and one of these layers Or it can add to two or more layers.

(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, and Q ₂ represents a carbamoyl group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a sulfonyl group, or Represents a sulfamoyl group.

In the general formula (SE1), the aromatic group or heterocyclic group represented by Q ₁ is preferably a 5- to 7-membered unsaturated ring. Preferred examples include benzene ring, pyridine ring, pyrazine ring, pyrimidine ring, pyridazine ring, 1,2,4-triazine ring, 1,3,5-triazine ring, pyrrole ring, imidazole ring, pyrazole ring, 1,2 , 3-triazole ring, 1,2,4-triazole ring, tetrazole ring, 1,3,4-thiadiazole ring, 1,2,4-thiadiazole ring, 1,2,5-thiadiazole ring, 1,3,4 -Oxadiazole ring, 1,2,4-oxadiazole ring, 1,2,5-oxadiazole ring, thiazole ring, oxazole ring, isothiazole ring, isoxazole ring, thiophene ring, etc. are preferable, and these Also preferred are fused rings in which the rings are fused together.

In the formula, R ¹¹ represents an alkyl group, an acyl group, an acylamino group, a sulfonamide group, an alkoxycarbonyl group, or a carbamoyl group. R ¹² 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 ¹³ and R ¹⁴ each represent a group that can be substituted on the benzene ring. R ¹³ and R ¹⁴ may be linked to each other to form a condensed ring.

In the general formula (SE2), when R ¹³ and R ¹⁴ are connected to each other to form a condensed ring, the condensed ring is particularly preferably a naphthalene ring. When the general formula (SE2) is a naphthol compound, R ¹¹ is preferably a carbamoyl group. Of these, a benzoyl group is particularly preferable. R ¹³ 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) nZ
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 a compound described in “0017” of JP-A No. 2004-21068, a compound described in “0027” of US Patent Application Publication No. 2002/0025498, MF-1 to MF-3, Examples thereof include 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 an ultrasonic wave 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 and 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.

  The antifogging and image stabilizer that can be used in the silver salt photothermographic dry imaging material of the present invention will be described.

  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. As specific examples of compounds having these functions, for example, biimidazolyl compounds, iodonium compounds and halogen atoms described in paragraphs “0096” to “0128” of JP-A-2003-270755 are released as active species. The compound etc. which can be mentioned.

  Further, polymers having at least one repeating unit of a monomer having a halogen radical releasing group as disclosed in JP-A No. 2003-91054, and vinyl sulfones described in paragraph “0013” of JP-A No. 6-208192 Specific examples include various antifogging and image stabilizers such as β-halosulfones and vinyl type inhibitors having an electron withdrawing group described in Japanese Patent Application No. 2004-234206.

  When the reducing agent used in the present invention has an aromatic hydroxyl group (—OH), particularly in the case of bisphenols, a non-reducing compound having a group capable of forming a hydrogen bond with these groups is used. It is preferable to use together. Specific examples of particularly preferred hydrogen bonding compounds in the present invention include, for example, compounds (II-1) to (II-40) described in paragraphs “0061” to “0064” of JP-A-2002-90937. Is mentioned.

  On the other hand, many compounds that can release halogen atoms as active species are known as antifogging and image stabilizers. Specific examples of the compound that generates these active halogen atoms include compounds represented by general formula (9) described in “0264” to “0271” of JP-A-2002-287299.

  The addition amount of these compounds is preferably within a range in which the increase in printout silver due to the formation of silver halide due to the reaction between the halogen released from the compound and silver ions does not become a problem. Specific examples of the compound that generates these active halogen atoms include, in addition to the above-mentioned publications, compounds (III-1) to 3 described in paragraphs “0086” to “0087” of JP-A No. 2002-169249. (III-23), compounds 1-1a to 1-1o and 1-2a to 1-2o described in paragraphs “0031” to “0034” of JP-A-2003-50441, and paragraphs “0050” to “0056” Compounds 2a to 2z, 2aa to 2ll, 2-1a to 2-1f, Compounds 4-1 to 4-32 described in paragraphs “0055” to “0058” of JP-A No. 2003-91054, paragraphs “0069” to Examples thereof include compounds 5-1 to 5-10 described in “0072”.

  Examples of the antifoggant preferably used in the present invention include compound examples a to j described in paragraph “0012” of JP-A-8-314059 and paragraph “0028” of JP-A-7-209797. Thiosulfonate esters A to K, compound examples (1) to (44) described from p14 of JP-A No. 55-140833, compounds described in paragraph “0063” of JP-A No. 2001-13627 (I-1 ) To (I-6), (C-1) to (C-3) described in paragraph “0066”, and compounds (III-1) to (III-) described in paragraph “0027” of JP-A-2002-90937. 108), compounds VS-1 to VS-7 and compounds HS-1 to HS-5 described in paragraph “0013” of JP-A-6-208192 as compounds of vinyl sulfones and / or β-halo sulfones. KS-1 to KS-8 compounds described in JP-A No. 2000-330235 as sulfonylbenzotriazole compounds, PR-01 to PR-08 described in JP-T-2000-515995 as substituted propene nitrile compounds, Examples thereof include compounds (1) -1 to (1) -132 described in paragraphs “0042” to “0051” of JP-A-2002-207273.

  The antifoggant is generally used in an amount of at least 0.001 mole per mole of silver. Usually, the range is 0.01 to 5 moles of the compound relative to the moles of silver, preferably 0.02 to 0.6 moles of the compound relative to the moles of silver.

  In addition to the above compounds, the silver salt photothermographic dry imaging material of the present invention may contain various compounds conventionally known as antifoggants, but the same reaction activity as the above compounds. Even if it is a compound which can produce | generate a seed | species, the compound from which an antifogging mechanism differs may be sufficient. For example, U.S. Pat. Nos. 3,589,903, 4,546,075, 4,452,885, JP-A-59-57234, U.S. Pat. No. 3,874,946. Examples thereof include compounds described in the specification, JP 4,756,999, JP-A-9-288328, and JP-A-9-90550. Further, as other antifoggants, compounds disclosed in US Pat. No. 5,028,523 and European Patent Nos. 600,587, 605,981 and 631,176 are exemplified. Can be mentioned.

(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 (for example, succinimide, phthalimide, naphthalimide, N-hydroxy-1,8-naphthalimide); mercaptans (for example, 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)
(Rf- (L) n-) p- (Y) m- (A) q
In the formula, Rf 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, and A represents An anion group or a salt thereof is represented, 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), Rf represents a substituent containing a fluorine atom. Examples of the substituent containing a fluorine atom include a fluorinated alkyl group having 1 to 25 carbon atoms (for example, a 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.). Rf preferably has 2 to 8 carbon atoms, more preferably 2 to 6 carbon atoms. Rf 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. An anionic group (A) is further introduced into the compound (partially Rf-modified alkanol compound) obtained by addition reaction or condensation reaction with 3 to 4 aromatic compounds or hetero compounds by, for example, sulfate esterification. 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.

  Below, the preferable specific compound of the fluorine-type surfactant represented by general formula (SF) is shown.

  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 property adjustment organic solid lubricant particles)
The silver salt photothermographic dry imaging material is used for contact between various devices and the photothermographic material during the winding, rewinding, and transporting of the photosensitive material in the manufacturing process such as coating, drying and processing, or backing with the photosensitive surface. It is often undesirably affected by contact between the photothermographic materials such as between the surfaces. 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 diameter of 1 μm to 30 μm, and these organic solid lubricant particles are dispersed by a polymer dispersant. This is good. 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.

  Examples of organic solid lubricant particles made of polyethylene and polypropylene are shown below, but the present invention is not limited to these.

[Melting point ° C]
PW-1 Polytetrafluoroethylene 321
PW-2 Polypropylene / polyethylene copolymer 142
PW-3 Polyethylene (low density) 113
PW-4 Polyethylene (high density) 126
PW-5 Polypropylene 145
In the silver salt photothermographic dry imaging material of the present invention, the organic solid lubricant particles are preferably a compound represented by the following general formula (6).

General formula (6)
_{(R 61) p6 -X 61 -L} 6 -X 62 - (R 62) q6
In the formula, each of R ₆₁ and R ₆₂ is a substituted or unsubstituted alkyl group, alkenyl group, aralkyl group or aryl group having 6 to 60 carbon atoms, and when p6 or q6 is 2 or more, a plurality of R ₆₁ and R 62 are present. ₆₂ may be the same as or different from each other. X ₆₁ and X ₆₂ each represent a divalent linking group containing a nitrogen atom. L ₆ represents a substituted or unsubstituted p6 + q6 valent alkyl group, alkenyl group, aralkyl group, or aryl group.

In the compound represented by the general formula (6), the total carbon number is not particularly limited, but is generally preferably 20 or more, and more preferably 30 or more. Examples of the substituent that the alkyl group, alkenyl group, aralkyl group or aryl group in the definition of R ₆₁ and R ₆₂ may have include, for example, a halogen atom, a hydroxy group, a cyano group, an alkoxy group, an aryloxy group Alkylthio group, arylthio group, alkoxycarbonyl group, aryloxycarbonyl group, amino group, acylamino group, sulfonylamino group, ureido group, carbamoyl group, sulfamoyl group, acyl group, sulfonyl group, sulfinyl group, aryl group and alkyl group Can be mentioned. These groups may further have a substituent. Preferred substituents are a halogen atom, hydroxy group, alkoxy group, alkylthio group, alkoxycarbonyl group, acylamino group, sulfonylamino group, acyl group and alkyl group. As a halogen atom, a fluorine atom and a chlorine atom are preferable.

The alkyl component in the alkoxy group, alkylthio group and alkoxycarbonyl group is the same as the alkyl group of R ₆₂ described later. The amino group of the acylamino group and sulfonylamino group may be an N-substituted amino group, and the substituent is preferably an alkyl group. The groups bonded to the acylamino group, the carbonyl group of the acyl group, and the sulfonyl group of the sulfonylamino group are an alkyl group and an aryl group, and the above alkyl groups are preferred.

R ₆₁ and R ₆₂ are substituted or unsubstituted alkyl, alkenyl, aralkyl or aryl groups having 6 to 60 carbon atoms, preferably 6 to 40 carbon atoms, more preferably 10 to 30 carbon atoms, The alkyl group, alkenyl group, and aralkyl group may be linear, branched, or cyclic, or may be a mixture thereof. Examples of preferred R ₆₁ and R ₆₂ include octyl, t-octyl, dodecyl, tetradecyl, hexadecyl, 2 _- hexyldecyl, octadecyl, C _n H _2n-1 (n represents 20 to 60), eicosyl, docosanyl, Menlicinyl, octenyl, myristolyl, oleyl, erucyl, phenyl, naphthyl, benzyl, nonylphenyl, dipentylphenyl, cyclohexyl groups and groups having these substituents can be exemplified.

X ₆₁ and X ₆₂ each represent a divalent linking group containing a nitrogen atom, preferably —CONR ₃ —, —NR ₄ CONR ₅ —, or —NR ₆ COO—.

L ₆ represents a substituted or unsubstituted p6 + q6 valent alkyl group, alkenyl group, aralkyl group, or aryl group. Although carbon number of a hydrocarbon group is not specifically limited, Preferably it is 1-60, More preferably, it is 1-40, More preferably, it is 10-40. p6 + q6 valence of the "p6 + q6 valent" in the hydrocarbon group are excluded the p6 + q6 hydrogen atoms in the hydrocarbon, there p6 amino X ₆₁ - indicating that the group and q6 amino -X ₆₂ group is attached . p6 and q6 represent an integer of 0 to 6, 1 ≦ p6 + q6 ≦ 6, and preferably 1 ≦ p6 + q6 ≦ 4. Moreover, the case where both p6 and q6 are 1 is preferable.

  The compound represented by the general formula (6) may be a synthetic product or a natural product. Synthetic compounds made from higher fatty acids and alcohols of natural products, even natural products or synthetic products, include those having different carbon numbers, straight chain and branched compounds, and mixtures thereof. There is no problem using it. From the viewpoint of the quality stability of the composition, a synthetic product is preferable.

  Although the specific example of a compound represented with preferable General formula (6) below is shown, this invention is not limited to these.

[Melting point ° C]
OW-1 Lauric acid amide 87
OW-2 Palmitic acid amide 100
OW-3 Stearic acid amide 101
OW-4 behenic acid amide 98
OW-5 Hydroxystearic acid amide 107
OW-6 Oleic acid amide 75
OW-7 erucic acid amide 81
OW-8 Ricinoleic acid amide 62
OW-9 N-lauryl lauric acid amide 77
OW-10 N-palmityl palmitate amide 91
OW-11 N-stearyl stearate amide 95
OW-12 N-oleyl oleic acid amide 65
OW-13 N-stearyl oleic acid amide 67
OW-14 N-oleyl stearic acid amide 74
OW-15 N-stearyl erucic acid amide 69
OW-16 N-oleyl palmitate amide 68
OW-17 N-stearyl-12-hydroxystearic acid amide 102
OW-18 N-oleyl-12-hydroxystearic acid amide 90
OW-19 Methylol stearic acid amide 110
OW-20 Methylol Behenate Amide 110
OW-21 Methylenebisstearic acid amide 142
OW-22 Methylenebislauric acid amide 131
OW-23 Methylenebishydroxystearic acid 143
OW-24 Ethylene biscaprylic acid amide 165
OW-25 Ethylene Biscapric Acid Amide 161
OW-26 ethylene bislauric acid amide 157
OW-27 Ethylene bis stearic acid amide 145
OW-28 Ethylenebisisostearic acid amide 106
OW-29 Ethylene bishydroxystearic acid 145
OW-30 Ethylene bisbehenic acid amide 142
OW-31 Hexamethylenebisstearic acid amide 140
OW-32 Hexamethylenebisbehenic acid amide 142
OW-33 Hexamethylenebishydroxystearic acid amide 135
OW-34 Butylenebishydroxystearic acid amide 140
OW-35 N, N'-distearyl adipic acid amide 141
OW-36 N, N'-distearyl sebacic acid amide 136
OW-37 Methylenebisoleic acid amide 116
OW-38 Ethylenebisoleic acid amide 119
OW-39 Ethylenebiserucic acid amide 120
OW-40 Hexamethylenebisoleic acid amide 110
OW-41 N, N′-dioleyl adipate amide 118
OW-42 N, N′-dioleyl sebacic acid amide 113
OW-43 m-xylylene stearic acid amide 123
OW-44 N, N'-distearylisophthalic acid amide 125
OW-45 ethanolamine distearate 82
OW-46 N-butyl-N'-stearyl urea 94
OW-47 N-phenyl-N'-stearyl urea 99
OW-48 N-stearyl-N'-stearyl urea 109
OW-49 Xylylenebisstearyl urea 166
OW-50 Toluylenebisstearyl urea 172
OW-51 Hexamethylenebisstearyl urea 173
OW-52 Diphenylmethanebisstearylurea 206
The organic solid lubricant in the present invention is preferably used in a state of being dispersed in a coating solution in advance. As the name suggests, the organic solid lubricant has a property that the surface is slippery, and therefore, the affinity between water and the organic solvent is not sufficiently high in many cases. It may develop sedimentation. Aggregation or sedimentation in the coating solution is undesirable because it causes coating failure when processed into a film. Examples of a method for improving the stability of the dispersion include a method of modifying the surface and using an electrostatic effect, and a method of using a steric hindrance effect using a surface adsorbing layer by a polymer dispersant. The former is a general dispersion stabilization method, but since it is concerned about the influence of the surface modifier itself on other performance from the point of use in the photothermographic material, it is effective in both aqueous and non-aqueous systems. The latter method that is easy to express is preferred.

  As the polymer dispersant, a binder used in the photosensitive material can be used. Specifically, polyvinyl butyral, polyvinyl acetal, polyvinyl alcohol, cellulose acetate butyrate, cellulose acetate propionate, or the like can be used.

  The amount of the polymer dispersant is preferably used in the range of 1% by mass to 200% by mass with respect to the organic solid lubricant particles that are to be dispersed. Although the dispersion method is not particularly limited, a dissolver type, an ultrasonic type, a pressure type, or the like can be used, and it is preferable to carry out a dispersion treatment with a dispersion device having a cooling device so as not to generate heat.

  The average particle diameter of the organic solid lubricant particles refers to the average particle diameter after dispersion by the following method. In order to determine the average particle size according to the present invention, a dispersion containing the compound according to the present invention is diluted, dropped onto a grid with a carbon support film, and dried, and then a transmission electron microscope (for example, JEOL Ltd.) is used. Manufactured, 2000FX type), and after taking a direct image at a magnification of 5000 times, the scanner captures the negative as a digital image, and using an appropriate image processing software, each particle size (equivalent circle diameter) is 300 or more. The average particle diameter can be determined from the arithmetic average.

  In the light-sensitive material of the present invention, at least one layer on the support contains the compound represented by the general formula (6), 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 (A) is preferable.

Formula (A)
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.

In the general formula (A), examples of the fluorine-containing aliphatic group represented by Rf ₁ and Rf ₂ include aliphatic groups composed of linear, branched and cyclic groups, or combinations thereof, such as alkylcycloaliphatic groups. Can be mentioned. Preferred fluorine-containing aliphatic groups are each a fluoroalkyl group having 1 to 20 carbon atoms (such as —C ₄ F ₉ and —C ₈ F ₁₇ ), and a sulfofluoroalkyl group (—C ₇ F ₁₅ SO ₃ , —C _8). F ₁₇ SO ₃ — etc.), C _n F _{2n + 1} SO ₂ N (R ₁ ) R ₂ — group (R ₁ is a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an alkoxy group, an alkyl carboxyl group or an aryl group, respectively. R ₂ represents an alkylene group having 1 to 20 carbon atoms and an alkylene carboxyl group, and n represents an integer of 1 to 20. C ₇ F ₁₅ SO ₂ N (C ₂ H ₅ ) CH ₂ —, C ₈ F ₁₇ SO ₂ N (CH ₂ COOH) CH ₂ CH ₂ CH ₂ — and the like), which may further have a substituent.

  AO is a group having an alkyleneoxy group such as ethyleneoxy, propyleneoxy, i-propyleneoxy, and may have a substituent such as an amino group at the terminal. n is preferably an integer of 5 to 15.

A-1: C ₁₂ F ₂₅ (CH ₂ CH ₂ O) ₂₄ C ₁₂ F ₂₅
A-2: C ₈ F ₁₇ (CH ₂ CH ₂ O) ₈ C ₈ F _{17
A-3: C 7 F 15} CH 2 CH (OH) CH 2 (CH 2 CH 2 O) 15 CH 2 CH (OH) CH 2 C 7 F 15
A-4: C ₇ F ₁₅ (CH ₂ CH ₂ O) ₁₀ C ₇ F _{15
A-5: C 12 F 25} (CH 2 CH 2 O) 15 C 12 F 25
_{A-6: C 8 F 17} CH 2 CH (OH) CH 2 (CH 2 CH 2 O) 20 CH 2 CH (OH) CH 2 C 8 F 17
A-7: C ₈ F ₁₇ (CH ₂ CH ₂ O) ₁₈ C ₈ F ₁₇
A-8: C ₈ F ₁₇ (CH ₂ CH ₂ O) ₂₀ C ₈ F _{17
A-9: C 7 F 15} SO 2 N (C 2 H 5) CH 2 (CH 2 CH 2 O) 22 CH 2 N (CH 3) SO 2 C 7 F 15
_{A-10: C 9 F 17} O (CH 2 CH 2 O) 22 C 9 F 17
Moreover, there is no restriction | limiting in particular as an anionic fluorine-containing surfactant which can be used by this invention, Although a specific compound is shown below, this invention is not limited to these.

The amount of each fluorine-containing surfactant used in the present invention is generally 0.01 to 1 g per 1 m ² of the photosensitive material, and preferably 10 to 500 mg. More preferably, it is 50-300 mg.

  As the fluorine-containing surfactant used in the present invention, in addition to the above, ionic fluorine-based surfactants described in JP-A-60-244945, JP-A-63-306437, and JP-A-1-24245. Surfactants, fluorine-containing surfactants used in combination with anions and cations described in JP-A-5-197068, JP-A-5-204115, and the like can be used.

  The addition layer of the fluorine-containing surfactant used in the present invention is not particularly limited and may be in any layer, but is preferably contained in the outermost surface layer.

(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. Examples of containing different atoms include, for example, addition of Al, In, etc. to ZnO, addition of Sb, Nb, P, halogen elements, etc. to SnO ₂ , and Nb, Ta to TiO ₂ . 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 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, applying a plurality of these coating solutions simultaneously, and then performing a 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.

(Odor and pollution prevention technology)
Technology for reducing / preventing odors and contamination caused by volatilization of low molecular weight compounds from the material in the thermal development apparatus (laser imager) during thermal development of the silver salt photothermographic dry imaging material of the present invention A preferred embodiment will be described.

  In the silver salt photothermographic dry imaging material of the present invention, the protective layer preferably has a function of preventing contaminants generated during the heat development from volatilizing or adhering to the outside of the photosensitive material. Therefore, the protective layer binder is preferably a polymer having cellulose acetate having an acetylation degree of 50% to 58% and a vinyl alcohol unit having a saponification degree of 75% or less. In particular, vinyl acetate polymer and polyvinyl alcohol are preferable.

  As the cellulose acetate, cellulose acetate having an acetylation degree of 50% or more and 58% or less is preferable. On the other hand, the polyvinyl alcohol is preferably a low crystalline polyvinyl alcohol having a saponification degree of 75% or less. The lower limit of the saponification degree is preferably 40%, more preferably 60%.

  The protective layer is used by mixing with a polymer other than the above, for example, a polymer described in US Pat. Nos. 6,352,819, 6,352,820, 6,350,561, etc. You can also. The ratio is preferably 0 to 90% by volume, more preferably 0 to 40% by volume.

  The crosslinking agent for the binder is preferably an isocyanate compound, a silane compound, an epoxy compound or an acid anhydride.

  Furthermore, it is preferable to reduce the amount of substances that volatilize from the photosensitive material during development by using an acid group scavenger. As an acid group scavenger, an isocyanate type represented by the following general formula (X-1), an epoxy type represented by the following general formula (X-2), and a phenol represented by the following general formula (X-3) Examples thereof include amines, diamines represented by the following general formula (X-4), and carbodiimides represented by the general formula (CI) described later. In particular, carbodiimide compounds are preferred.

  In the formula, Rx represents a substituent, Rx ′ represents a divalent linking group, and n21 represents 1 to 4.

(Packaging body)
When storing the silver salt photothermographic dry imaging material of the present invention, oxygen transmission rate and / or water transmission rate are used to prevent density change and fog generation over time, or to improve curling, curling, etc. 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 · 90% RH · day or less (according to JIS Z0208 cup method), more preferably 0.005 g / m ² · 40 ° C. · 90% RH · Day or less, more preferably 0.001 g / m ² · 40 ° C · 90% RH · day or less.

  Specific examples of the packaging material for the photothermographic material include, for example, JP-A-8-254793, JP-A-2000-206653, JP-A-2000-235241, JP-A-2002-062625, JP-A-2003-015261, JP 2003-057990 A, JP 2003-084397 A, JP 2003-098648 A, JP 2003-098635 A, JP 2003-107635 A, JP 2003-131337 A, JP 2003-146330 A, Special It is a packaging material described in Japanese Patent Application Laid-Open No. 2003-226439 and Japanese Patent Application Laid-Open No. 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%.

Example 1
[Preparation of underdrawn support]
Corona discharge treatment is performed on both sides of a biaxially stretched polyethylene terephthalate film having a blue dye concentration of 0.135 under the condition of 10 W / m ² · min. It was coated to 0.06 μm and dried at 140 ° C. Subsequently, the following back surface side undercoat upper layer coating solution was coated to a dry film thickness of 0.2 μm and then dried at 140 ° C. On the opposite 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, and then the following photosensitive layer side undercoat upper layer coating solution is dried film thickness. After coating to 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%) 91g
(Synthesis by the method described in JP-A-10-059720)
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
Spherical silica matting agent Seahoster KE-P50 (Nippon Shokubai Co., Ltd.) 0.3g
Distilled water was added to make 1000 ml, and a coating solution was obtained.

<< Synthesis of Modified Aqueous Polyester A >>
In a polymerization reactor, 35.4 parts by mass of dimethyl terephthalate, 33.63 parts by mass of dimethyl isophthalate, 17.92 parts by mass of 5-sulfo-isophthalic acid dimethyl sodium salt, 62 parts by mass of ethylene glycol, calcium acetate monohydrate 0.065 parts by mass and 0.022 parts by mass of manganese acetate tetrahydrate were added, and after a transesterification reaction was performed while distilling off methanol at 170 to 220 ° C. in a nitrogen stream, 0.04 trimethyl phosphate was obtained. As a polycondensation catalyst, 0.04 part by mass of antimony trioxide and 6.8 parts by mass 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. Esterification was performed. Thereafter, the inside of 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.

  1900 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. Into this, 6.52 ml of a 24% aqueous solution of ammonium peroxide was added, and a monomer mixture (28.5 g of glycidyl methacrylate, 21.4 g of ethyl acrylate, 21.4 g of methyl methacrylate) was dropped 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 A whose solid content concentration is 18 mass%.

<< Coating liquid for photosensitive layer side undercoat >>
Copolymer latex of styrene / acetoacetoxyethyl methacrylate / glycidyl methacrylate / n-butyl acrylate (40/40/20 / 0.5) (solid content 30%) 70 g
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 B (solid content 18%) 80.0 g
Surfactant A 0.4g
Spherical silica matting agent Seahoster KE-P50 (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.

<< Synthesis of Modified Aqueous Polyester B >>
The modified aqueous polyester B was prepared in the same manner as the knitted aqueous polyester A except that the precursor solution was 1800 ml, the monomer mixture was 31 g of styrene, 31 g of acetoacetoxyethyl methacrylate, 61 g of glycidyl methacrylate, and 7.6 g of n-butyl acrylate. A solution was made.

(Preparation of silver halide emulsion)
<Solution A1>
66.2 g of phenylcarbamoylated gelatin
_{HO (CH 2 CH 2 O)} n - (CH (CH 3) CH 2 O) 17 - (CH 2 CH 2 O) m H
(M + n = 5-7) (10% methanol aqueous solution) 10 ml
Potassium bromide 0.32g
Finish 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
Finish to 660 ml with water <Solution D1>
Potassium bromide 154.9g
4.41 g of potassium iodide
15 ml of iron (II) hexacyanide (0.5% solution)
0.93 ml potassium hexachloroiridate (III) (1% solution)
Finish 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
Finish to 20 ml with water <Solution G1>
56% aqueous acetic acid solution 10.0ml
<Solution H1>
Anhydrous sodium carbonate 1.16g
Using a mixing stirrer disclosed in Japanese Patent Publication No. 58-58288, the solution A1 is mixed with 1/4 of the solution B1 and the total amount of the solution C1 at 35 ° C. and pAg 8.09 at the same time. Nucleation was performed by adding 4 minutes and 45 seconds by a mixing method. After 1 minute, the entire amount of solution F1 was added. During this time, the pAg was appropriately adjusted using the solution E1. After 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 the temperature at 35 ° C. and pAg 8.09. After stirring for 5 minutes, the temperature was lowered to 30 ° C., the entire amount of the solution G1 was added, and the silver halide emulsion was precipitated. The supernatant was removed leaving 2000 ml of the sedimented portion, 10 liters 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 liters of water was added, and after stirring, the silver halide emulsion was precipitated. 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 100 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 photosensitive silver halide grain emulsion.

  This emulsion was monodispersed cubic silver iodobromide grains having an average grain size of 0.043 μm and a [100] face ratio of 92%.

(Preparation of aliphatic carboxylic acid silver salt particles 1-1 to 1-8)
Aliphatic carboxylate silver particles 1-1 to 1-8 were prepared using an apparatus as shown in FIG. In a tank 11, an aliphatic carboxylic acid (mol composition ratio is shown in Table 1) 450 g and a 90% amount of pure water adjusted to the concentration shown in Table 1 with stirring at 85 ° C., 5 M / L KOH aqueous solution After adding 252 ml over 5 minutes, the mixture was reacted for 60 minutes to obtain an aqueous potassium aliphatic carboxylate solution. Finally, additional pure water was added to obtain the concentrations shown in Table 1. Moreover, the silver nitrate aqueous solution of the density | concentration and quantity shown in Table 1 was prepared in the tank 12, and it heat-retained at 10 degreeC. While stirring TK pipeline homomixer type M manufactured by Special Machine Industries Co., Ltd. shown in FIG. 2 at 10000 rpm, the above-mentioned aliphatic carboxylate aqueous solution and silver nitrate aqueous solution are simultaneously added at a constant addition rate. The whole amount was added over the time shown in Table 1 and stocked in tank 15. During the addition, the tank 15 was kept at 30 ° C. Thereafter, the solid content was separated by suction filtration, and the solid content was washed with water at the temperature shown in Table 1 until the conductivity of the permeated water reached 30 μS / cm. The obtained dehydrated cake was dried under the conditions shown in Table 1 to obtain a dried powder of aliphatic carboxylic acid silver salt particles. The results of measuring the sphere equivalent average diameter and standard deviation of the resulting aliphatic carboxylic acid silver salt particles are also shown in Table 1. In the figure, 16 is a flow meter and 17 is a pump.

(Preparation of aliphatic carboxylic acid silver salt particles 2-1 to 2-16)
Aliphatic carboxylate silver particles 2-1 to 2-16 were prepared using an apparatus as shown in FIG. In tank 21, 450 g of aliphatic carboxylic acid (mol composition ratio is shown in Table 1) and 90% of pure water amount adjusted to the concentration shown in Table 1 while stirring at 85 ° C., 5 M / L KOH aqueous solution After adding 252 ml over 5 minutes, the mixture was reacted for 60 minutes to obtain an aqueous potassium aliphatic carboxylate solution. Finally, additional pure water was added to finish the whole amount as shown in Table 1. Moreover, the silver nitrate aqueous solution of the density | concentration and quantity shown in Table 1 was prepared in the tank 22, and it heat-retained at 10 degreeC. The above-mentioned aliphatic potassium carboxylate aqueous solution and silver nitrate aqueous solution were simultaneously added at a constant addition rate to the mixing device 24 over the time shown in Table 1 and stocked in the tank 26. During the addition, the tank 26 was kept at 30 ° C. Thereafter, the solid content was separated by suction filtration, and the solid content was washed with water at the temperature shown in Table 1 until the conductivity of the permeated water reached 30 μS / cm. The obtained dehydrated cake was dried under the conditions shown in Table 1 to obtain a dried powder of aliphatic carboxylic acid silver salt particles. The results of measuring the sphere equivalent average diameter and standard deviation of the resulting aliphatic carboxylic acid silver salt particles are also shown in Table 1. In the figure, 27 is a flow meter and 28 is a pump.

(Preparation of preliminary dispersion)
48.58 g of polyvinyl butyral resin BL-SHP (manufactured by Sekisui Chemical Co., Ltd.) was dissolved in 1457 g of methyl ethyl ketone (hereinafter abbreviated as MEK), and the above-mentioned was stirred with a dissolver DISPERMAT CA-40M manufactured by VMA-GETZMANN. A preliminary dispersion was prepared by gradually adding 500 g of the powdered aliphatic carboxylic acid silver salt prepared in the above and mixing well.

(Preparation of photosensitive emulsion dispersion)
Media type disperser filled with 80% of the internal volume of 0.5 mm diameter zirconia beads (Toray Seles made by Toray) so that the pre-dispersed liquid prepared above is 1.5 minutes in the mill using a pump. The emulsion was supplied to DISPERMAT SL-C12EX type (manufactured by VMA-GETZMANN) and dispersed at a mill peripheral speed of 8 m / s at 25 ° C. to prepare a photosensitive emulsion dispersion.

(Addition of silver halide grain emulsion)
<< Synthesis of Silver Halide Grain Dispersing Polymers A, B, C >>
A 0.5 liter four-necked separable flask was equipped with a dropping device, a thermometer, a nitrogen gas inlet tube, a stirring device and a reflux condenser, and 50 g of methyl ethyl ketone and a monomer other than NIPAM having a composition ratio shown in Table 2 ( Unit g) and 0.12 g of lauryl peroxide were charged and heated to the temperatures shown in Table 2. Furthermore, the liquid which melt | dissolved the NIPAM monomer (unit g) of Table 2 in methyl ethyl ketone 43g was dripped over 2 hours in the flask. Thereafter, when the temperature was raised over 1 hour to reach a reflux state, a solution obtained by dissolving 0.17 g of lauryl peroxide in 33 g of methyl ethyl ketone was dropped into the flask over 2 hours and reacted at the same temperature for further 3 hours. . Thereafter, a solution obtained by dissolving 0.33 g of methyl hydroquinone in 107 g of methyl ethyl ketone was added and cooled, and polymer solutions A, B, and C of 30% by mass of polymer were obtained. The molecular weight was determined by GPC as a weight average molecular weight in terms of polystyrene.

PME-400: methacrylate PSE-400 having — (EO) _m —CH ₃ (m≈9): methacrylate (EO; ethyleneoxy group having — (EO) _m —C ₁₈ H ₃₇ (m≈9) )
The above are all made from Japanese fats and oils.
NIPAM: N-isopropylacrylamide DAAM: diacetone acrylamide (Kyowa Hakko).

Preparation of polymer dispersed silver halide emulsions A to C (dispersion of silver halide grains in methyl ethyl ketone solvent)
33 g of the polymer A solution was finished with 121 g of methanol and stirred at 45 ° C. for 30 minutes. The silver halide emulsion (59.2 g) adjusted to 45 ° C. was added dropwise over 20 minutes, and the mixture was further stirred for 30 minutes. Thereafter, the temperature was lowered to 32 ° C. over 30 minutes, and then 600 g of methyl ethyl ketone was added dropwise over 30 minutes to obtain a polymer-dispersed silver halide emulsion A. A polymer-dispersed silver halide emulsion B was prepared in the same manner except that the polymer B solution was used. A polymer-dispersed silver halide emulsion C was prepared in the same manner except that the polymer C solution was used.

(Preparation of stabilizer solution)
A stabilizer solution was prepared by dissolving 1.0 g of Stabilizer 1 and 0.31 g of potassium acetate in 17.79 g of methanol.

(Preparation of infrared sensitizing dye liquid A)
30 mg of infrared sensitizing dye 1, 40 mg of infrared sensitizing dye 2, 2.5 g of 2-chloro-benzoic acid, 21.5 g of stabilizer 2 and 130 mg of 5-methyl-2-mercaptobenzimidazole, Infrared sensitizing dye solution A was prepared by dissolving in 140 g of MEK in the dark.

(Preparation of additive solution a)
27.98 g of developer A and 2.28 g of 4-methylphthalic acid, 111 mg of infrared dye A, 365 mg of leuco dye YA-10, 4.83 g of polyvinyl acetal resin BL-5Z (manufactured by Sekisui Chemical Co., Ltd.) ) Was dissolved in 172 g of MEK to obtain additive solution a.

(Preparation of additive liquid b)
3.31 g of antifoggant 2 was dissolved in 46.9 g of MEK to obtain additive liquid b.

(Preparation of additive liquid C)
3.34 g of phthalazine was dissolved in 23.0 g of MEK to obtain additive solution C.

(Preparation of photosensitive layer coating solution)
In an inert gas atmosphere (97% nitrogen), the photosensitive emulsion dispersion (50 g) and 8.80 g of MEK were kept at 18 ° C. with stirring, and 23. After adding 4 g and stirring for 30 minutes, 0.44 g of antifoggant 1 (11% methanol solution) was added and stirred for 1 hour. Further, 0.66 g of calcium bromide (11% methanol solution) was added and stirred for 20 minutes. Subsequently, 0.62 g of the stabilizer solution was added and stirred for 10 minutes, and then 4.93 g of the infrared sensitizing dye solution A was added and stirred for 1 hour. Thereafter, the temperature was lowered to 13 ° C. and further stirred for 30 minutes. While keeping the temperature at 13 ° C., 12.5 g of polyvinyl acetal resin BL-5Z (manufactured by Sekisui Chemical Co., Ltd.) was added as a binder resin and stirred for 30 minutes, and then tetrachlorophthalic acid (3.7 mass% MEK solution). ) 1.26 g was added and stirred for 30 minutes. While further stirring, addition of 24.8 g of additive a, 2.26 g of Desmodur N3300 / Mobay aliphatic isocyanate (23.3 mass% MEK solution), 5.03 g of additive b, 2.63 g of addition Liquid C was sequentially added and stirred to obtain a photosensitive layer coating liquid.

<Surface protective layer>
A coating solution having the following composition was prepared in the same manner as the photosensitive layer coating solution, and coated and dried on the photosensitive layer so as to have the following weight (per 1 m ² ) to form a photosensitive layer protective layer.

Cellulose acetate propionate 1.15g
(CAP141-20 (Eastman Chemical)
Polymethylmethacrylate 45mg
(Paraloid A-21 (Rohm and Haas)
Silica mat 25mg
(SYLYSIA 320 (5) (manufactured by Fuji Silysia Chemical Ltd.))
1,3-bis (vinylsulfonyl) -2-propanol 20mg
Benzotriazole 15mg
C ₉ F ₁₇ O (CH ₂ CH ₂ O) ₂₃ C ₉ F ₁₇ 42 mg
LiO ₃ S—CF ₂ CF ₂ CF ₂ —SO ₃ Li 1 mg
《Back layer》
A coating solution having the following composition was prepared, and a back layer was formed by coating and drying on the side opposite to the photosensitive layer coating surface so as to have the following weight (per 1 m ² ).

Cellulose acetate propionate 1.85g
(CAP482-20 (Eastman Chemical Co., Ltd.))
Polyester resin 95mg
(Vitel 2200B (manufactured by BOSTIC FINDLEY))
Silica matting agent 15mg
(Silicia 450 (Fuji Silysia Chemical Co., Ltd.))
Ethylene bis stearamide 60mg
Infrared dye A 3.5mg
C ₉ F ₁₇ O (CH ₂ CH ₂ O) ₂₃ C ₉ F ₁₇ 100 mg
LiO ₃ S—CF ₂ CF ₂ CF ₂ —SO ₃ Li 18 mg
《Preparation of silver salt photothermographic dry imaging material sample》
Using the above-described prepared photosensitive layer coating solution and surface protective layer coating solution, the total silver amount is as shown in Table 3 on the photosensitive layer side subbing layer of the prepared support using a known extrusion coater. The photosensitive layer coating solution was applied at the same amount as shown, and the surface protective layer coating solution was applied in multiple layers at the same time so as to have the above amount. Subsequently, a back layer coating solution was applied to the opposite surface so as to have the above weight. Thereafter, drying was performed for 10 minutes using a drying air having a drying temperature of 75 ° C. and a dew point temperature of 10 ° C. to prepare a sample.

  In addition, the kind of the aliphatic carboxylic acid silver salt in the photosensitive layer coating solution was changed as shown in Table 3 to prepare a sample.

<Exposure and development processing>
After processing the photothermographic dry imaging material samples 1 to 44 produced as described above to a half-cut size (34.5 cm × 43.0 cm), two samples packaged in the following packaging materials in an environment of 25 ° C. and 50% are obtained. Each bag was made. After storing at room temperature for 2 weeks, one bag was stored at 5 ° C./4 weeks, and the other bag was stored at 50 ° C./4 weeks, and then the following evaluation was performed.

(Packaging material)
PET 10 μm / PE 12 μm / aluminum foil 9 μm / Ny 15 μm / polyethylene 50 μm containing 3% carbon, oxygen permeability: 0 ml / Pa · m ² · 25 ° C · day, moisture permeability: 0 g / Pa · m ² · 25 ° C · day Barrier bag. Use paper tray.

(Sample evaluation)
Evaluation was performed simultaneously with exposure using the laser imager shown in FIG. 1 (installation area of 0.35 m ² mounted with an 810 nm semiconductor laser with a maximum output of 50 mW) (51, 52, and 53 in FIG. Each was set, and transported so as to be in contact with each other for 2 seconds, 2 seconds, and 6 seconds for a total of 10 seconds), and the obtained image was evaluated with a densitometer. Here, “thermal development at the same time as exposure” means a sheet photosensitive material made of a silver salt photothermographic dry imaging material, and development is performed on a part of the sheet that has already been exposed while being partially exposed. Means to be started. The distance between the exposed part and the developing part was 12 cm, and the linear velocity at this time was 30 mm / second. At this time, the conveyance speed from the photosensitive material supply unit to the image exposure unit, the conveyance rate at the image exposure unit, and the conveyance rate at the heat development unit were 30 mm / second, respectively. In addition, the position of the bottom surface of the photosensitive material stock tray located at the bottom was 45 cm high from the floor surface. The exposure and development were performed in a room adjusted to 23 ° C. and 50% RH. The exposure was performed in a stepped manner while reducing the exposure energy amount by log E0.05 step by step from the maximum output.

(Measurement of sensitivity, fog density and maximum density)
The density of the formed image obtained as described above was measured using a densitometer, and a characteristic curve consisting of a horizontal axis—exposure amount and a vertical axis—density was created. In the characteristic curve, the sensitivity is defined as the reciprocal of the exposure amount giving a density 1.0 higher than that of the unexposed area, and the minimum density fog density (minimum density) and the maximum density were measured. In addition, the sensitivity and the maximum density are expressed as relative values with 100 of each sample 1 being set. The results are shown in Table 3.

  As shown in Table 3, for comparison, it can be seen that the present invention maintains sensitivity and maximum density without fogging degradation under forced degradation storage conditions.

Example 2
1 except that the laser imager of FIG. 1 used for evaluation was modified so that the temperature of the first half of the cooling unit of 54 (film contact time 3 seconds) could be controlled and the laser imager was set as shown in Table 4. A photothermographic dry imaging material sample was prepared in the same manner as in Example 1, and the sample was evaluated. The results are shown in Table 3. Sensitivity and maximum density were expressed as relative values with 100 for each sample 1.

  As shown in Table 4, for comparison, it can be seen that the present invention maintains sensitivity and maximum density without fogging degradation under forced degradation storage conditions.

It is a side view which shows roughly the principal part of the heat development apparatus which concerns on this invention. It is a schematic diagram of the mixing apparatus which concerns on this invention. It is a schematic diagram of another mixing apparatus which concerns on this invention.

Explanation of symbols

11, 12, 13, 15 Tank 14 Mixing device 27 Flow meter 28 Pump 21, 22, 23, 26 Tank 24, 25 Mixing device 16 Flow meter 17 Pump 40a Device housing 45 Film storage portion 46 Pickup roller 47 Conveying roller pair 48 Curved surface guides 49a, 49b Conveying roller 56 Densitometer 57 Conveying roller pair 58 Film mounting part 59 Substrate part F Silver salt photothermographic dry imaging material d Gap

Claims (15)

Non-photosensitive aliphatic carboxylic acid silver salt particles, photosensitive silver halide particles, silver ion reducing agent, and silver salt photothermographic dry imaging material having heat-development processing method for non-photosensitive aliphatic carboxylic acid silver salt The grains are composed of 70 to 99.99 mol% silver behenate, the sphere equivalent average diameter is 0.05 to 0.5 μm, the standard deviation indicating the particle size distribution is 0.3 or less, and the silver salt A method for thermally developing a silver salt photothermographic dry imaging material, wherein the photothermographic dry imaging material is processed by a developing machine having a preheat zone that heats the photothermographic dry imaging material to 70 ° C or higher and 100 ° C or lower immediately before the thermal development step. The non-photosensitive aliphatic carboxylate silver salt particles of the silver salt photothermographic dry imaging material used in the heat development processing method according to claim 1 are simultaneously metered and mixed with an aqueous solution or dispersion of a fatty acid alkali metal salt and an aqueous silver nitrate solution. A silver salt photothermographic dry imaging material heat-development processing method, wherein the non-photosensitive aliphatic carboxylic acid silver salt particles are formed. The non-photosensitive aliphatic carboxylic acid silver salt particles of the silver salt photothermographic dry imaging material used in the heat development processing method according to claim 1, an aqueous solution or aqueous dispersion having a fatty acid alkali metal salt concentration of 1 to 5% by mass; A non-photosensitive aliphatic carboxylic acid silver salt prepared by simultaneously metering and mixing an aqueous silver nitrate solution having a concentration of 1 to 15% by mass and a molar ratio of the silver nitrate to the fatty acid alkali metal salt being 0.9 to 1.1 A method for thermally developing a silver salt photothermographic dry imaging material, characterized by comprising salt particles. A non-photosensitive aliphatic carboxylic acid silver salt particle of a silver salt photothermographic dry imaging material used in the heat development processing method according to claim 1 or 3, wherein the fatty acid alkali metal salt aqueous solution or aqueous dispersion and silver nitrate aqueous solution are transferred. A method for thermally developing a silver salt photothermographic dry imaging material, characterized in that it is non-photosensitive aliphatic carboxylic acid silver salt particles formed by simultaneous metering and mixing. The non-photosensitive aliphatic carboxylic acid silver salt particles of the silver salt photothermographic dry imaging material used in the heat development processing method according to claim 1, 3 or 4 comprise an aqueous solution or aqueous dispersion of a fatty acid alkali metal salt and an aqueous silver nitrate solution. Silver salt photothermographic drying characterized by non-photosensitive aliphatic carboxylic acid silver salt particles formed by simultaneous metering and mixing, washed with water at 50 ° C. or lower and dried at a phase transition temperature or lower. Thermal development processing method of imaging material. A non-photosensitive aliphatic carboxylate silver salt particle of a silver salt photothermographic dry imaging material used in the heat development processing method according to claim 1, 3, 4, or 5 is an aqueous solution or dispersion of a fatty acid alkali metal salt and an aqueous silver nitrate solution. Silver salt photothermographic dry imaging characterized by non-photosensitive aliphatic carboxylic acid silver salt grains formed by simultaneous metering and mixing in the absence of said photosensitive silver halide grains Heat development processing method of material. Non-photosensitive aliphatic carboxylic acid silver salt particles, photosensitive silver halide particles, silver ion reducing agent, and silver salt photothermographic dry imaging material having heat-development processing method, wherein the non-photosensitive aliphatic carboxylic acid silver salt A silver salt photothermographic dry particle comprising 70 to 99.99 mol% silver behenate, having a sphere equivalent average diameter of 0.05 to 0.5 μm and a standard deviation indicating a particle size distribution of 0.3 or less. A silver salt photothermographic dry imaging material characterized in that the imaging material is processed in a developing machine having a slow cooling zone in which the development is stopped by adjusting the temperature to a temperature lower by 10 to 20 ° C. immediately after the heat development step. Thermal development processing method. The non-photosensitive aliphatic carboxylate silver salt particles of the silver salt photothermographic dry imaging material used in the heat development processing method according to claim 7 are simultaneously metered and mixed with an aqueous solution or aqueous dispersion of a fatty acid alkali metal salt and an aqueous silver nitrate solution. A silver salt photothermographic dry imaging material heat-development processing method, wherein the non-photosensitive aliphatic carboxylic acid silver salt particles are formed. The non-photosensitive aliphatic carboxylic acid silver salt particles of the silver salt photothermographic dry imaging material used in the heat development processing method according to claim 7 are an aqueous solution or aqueous dispersion having a fatty acid alkali metal salt concentration of 1 to 5% by mass; A non-photosensitive aliphatic carboxylic acid silver salt prepared by simultaneously metering and mixing an aqueous silver nitrate solution having a concentration of 1 to 15% by mass and a molar ratio of the silver nitrate to the fatty acid alkali metal salt being 0.9 to 1.1 A method for thermally developing a silver salt photothermographic dry imaging material, characterized by comprising salt particles. The non-photosensitive aliphatic carboxylic acid silver salt particles of the silver salt photothermographic dry imaging material used in the heat development processing method according to claim 7 or 9, wherein the fatty acid alkali metal salt aqueous solution or aqueous dispersion and silver nitrate aqueous solution are transferred. A method for thermally developing a silver salt photothermographic dry imaging material, characterized in that it is non-photosensitive aliphatic carboxylic acid silver salt particles formed by simultaneous metering and mixing. The non-photosensitive aliphatic carboxylic acid silver salt particles of the silver salt photothermographic dry imaging material used in the thermal development processing method according to claim 7, 9 or 10 comprise an aqueous solution or aqueous dispersion of a fatty acid alkali metal salt and an aqueous silver nitrate solution. Silver salt photothermographic drying characterized by non-photosensitive aliphatic carboxylic acid silver salt particles formed by simultaneous metering and mixing, washed with water at 50 ° C. or lower and dried at a phase transition temperature or lower. Thermal development processing method of imaging material. A non-photosensitive aliphatic carboxylate silver salt particle of a silver salt photothermographic dry imaging material used in the thermal development processing method according to claim 7, 9, 10, or 11 is an aqueous solution or aqueous dispersion of a fatty acid alkali metal salt and an aqueous silver nitrate solution. Silver salt photothermographic dry imaging characterized by non-photosensitive aliphatic carboxylic acid silver salt grains formed by simultaneous metering and mixing in the absence of said photosensitive silver halide grains Heat development processing method of material. The silver salt photothermographic dry imaging material used in the method for thermal development of a silver salt photothermographic dry imaging material according to any one of claims 1 to 12 is subjected to heat development at a development temperature for 5 to 10 seconds. A method for thermally developing a silver salt photothermographic dry imaging material. The heat development processing method for a silver salt photothermographic dry imaging material according to claim 13, wherein the heat development processing is carried out by a heat developing machine having a heat-retaining zone for maintaining the development temperature in the developing section. The non-photosensitive aliphatic carboxylic acid silver salt particles and the photosensitive silver halide of the silver salt photothermographic dry imaging material used in the heat development processing method of the silver salt photothermographic dry imaging material according to any one of claims 1 to 14. A method for thermally developing a silver salt photothermographic dry imaging material, characterized by thermally developing a silver salt photothermographic dry imaging material having a total silver content of 0.8 to 1.5 g / m ² .

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