JP2000314939A - Heat-developable photosensitive material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat-developable photosensitive material capable of forming an image low in fog and high in Dmax (maximum density) and small in the rise of fog and fluctuation of sensitivity during storage, having good film toughness and especially adapted to formation of a printing plate, a scanner, and an image setter. SOLUTION: The heat-developable photosensitive material containing a nonphotosensitive silver salt, a photosensitive silver halide, a binder, and a nucleator is formed on a support by coating the support with a coating liquid containing one or more compounds capable of reacting with form aldehydes and fixing them, and drying it in conditions that the moisture content defined by the formula reaches 200% in a drying time of 5 sec-5 min from the start of the drying, and at least a layer formed by this drying is provided on the face of the support where an image forming layer containing the photosensitive silver halide is existent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photothermographic material, and more particularly to a scanner suitable for photolithography.
More specifically, the present invention relates to a photothermographic material for an image setter, more specifically, a photothermographic material for photoengraving which can obtain an image having low fog, high Dmax (maximum density), and little increase in fog and sensitivity during storage. It is about materials.

[0002]

2. Description of the Related Art There are many known photosensitive materials having a photosensitive layer on a support and forming an image by exposing the image. Among them, a technique for forming an image by thermal development is a system that can simplify environmental preservation and image forming means. In recent years, environmental preservation in the photoengraving field,
From the viewpoint of space saving, it is strongly desired to reduce the amount of processing waste liquid. There, you can use a laser scanner or a laser imagesetter to make the exposure more efficient,
There is a need for a technique relating to a photothermographic material for photolithography capable of forming a sharp black image having high resolution and sharpness. In these photothermographic materials,
By eliminating the use of solution processing chemicals, it is possible to provide customers with a simpler and more environmentally friendly thermal development processing system.

[0003] A method of forming an image by heat development is described in, for example, US Pat.
Morgan and B.A. "Thermal Proces Silver System (Thermally Proces)" by Shely
sed Silver Systems) A "(Imaging Processes and Materials
aterials) Neblette 8th edition, Sturge, V.E.
Walworth, A .; Shepp
Edited, page 2, 1969). Such photosensitive materials are prepared by dispersing a reducible non-photosensitive silver source (eg, an organic silver salt), a catalytically active amount of a photocatalyst (eg, silver halide), and a silver reducing agent, usually in an organic binder matrix. It is contained in. The photosensitive material is stable at room temperature, but when heated to a high temperature (for example, 80 ° C. or higher) after exposure, silver is reduced through a redox reaction between a reducible silver source (which functions as an oxidizing agent) and a reducing agent. Generate This oxidation-reduction reaction is promoted by the catalytic action of the latent image generated by the exposure. The silver formed by the reaction of the reducible silver salt in the exposed areas provides a black image, which contrasts with the unexposed areas, resulting in the formation of an image. In addition, the photothermographic materials have been conventionally known, but most of them are formed by applying a coating solution using an organic solvent such as toluene, methyl ethyl ketone (MEK), or methanol to form a photosensitive layer. I have. The use of an organic solvent as a solvent is disadvantageous not only in adverse effects on the human body in the manufacturing process but also in cost due to recovery of the solvent and the like.

Therefore, a method of forming a photosensitive layer (hereinafter also referred to as "aqueous photosensitive layer") using a coating solution of an aqueous solvent which does not have such a concern has been considered. For example,
JP-A-49-52626 and JP-A-53-116144 describe examples using gelatin as a binder. Also Japanese Patent Laid-Open No. 50-151
No. 138 describes an example using polyvinyl alcohol as a binder. Further, JP-A-60-61747 describes an example in which gelatin and polyvinyl alcohol are used in combination. As another example, JP-A-58-28737 describes an example of a photosensitive layer using water-soluble polyvinyl acetal as a binder. Certainly, when such a binder is used, a photosensitive layer can be formed using a coating solution of a water solvent, and the merits in terms of environment and cost are great.

However, when a polymer such as gelatin, polyvinyl alcohol, or water-soluble polyacetal is used as a binder, the compatibility with the organic silver salt is poor, so that not only a coated material which can be practically used due to the coated surface quality cannot be obtained, but also
The silver tone of the developed part becomes brown or yellow, which is far from black which is originally preferred, and the blackened density of the exposed part is low and the density of the unexposed part is high. Was. European Patent 762,196, JP 9-905
No. 50, etc., that a photosensitive silver halide grain used for a photothermographic material contains a metal ion or a metal complex ion of Group VII or VIII (Groups 7 to 10) of the periodic table; It is disclosed that high-contrast photographic characteristics can be obtained by incorporating a hydrazine derivative into a material. However, when a nucleating agent such as a hydrazine derivative is used in combination with the binder used in the above-mentioned aqueous solvent coating solution, a high-contrast image can be obtained. And there is a problem that the sensitivity fluctuation is large. Accordingly, a technology for providing a photothermographic material which is advantageous in terms of environment and cost, in which it is possible to obtain an image having low fog, high Dmax (highest density), and little fog increase and sensitivity fluctuation during storage. Was desired.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to solve these problems of the prior art. That is,
INDUSTRIAL APPLICABILITY The present invention can obtain an image having low fog, high Dmax (highest density), and little fog increase and sensitivity fluctuation during storage, particularly for photoengraving, particularly for scanners and imagesetters. An object of the present invention is to provide a photothermographic material having good film brittleness. Another object of the present invention is to provide a photothermographic material which can be applied in an aqueous system and is advantageous in terms of environment and cost.

[0007]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies in order to solve the above-mentioned problems, and as a result, it has been found that such compounds as the cyclic ketone or cyclic imine compound represented by the formula (S) described in the present specification. In addition, it has been found that by containing a compound capable of reacting with formaldehyde and fixing the same on the support surface side where the image forming layer is present, a change in photographic performance during storage can be suppressed, and By rapidly drying this layer under certain conditions to form it, the amount of the compound capable of reacting with formaldehyde and fixing the same can be reduced, and the storage conditions such as the storage environment change. The present inventors have found that a change in photographic performance due to the above can be reduced, and have provided the present invention. That is, according to the present invention, in a photothermographic material having a non-photosensitive silver salt, a photosensitive silver halide, a binder and a nucleating agent on a support, the formaldehyde is fixed by reacting with the formaldehyde. A coating solution containing one or more compounds capable of forming a film is dried under conditions that the time from the start of drying until the water content defined by the following formula reaches 200% is 5 seconds or more and 5 minutes or less. There is provided a photothermographic material characterized in that the photothermographic material has at least one layer formed on the support side where the image forming layer containing the photosensitive silver halide is present.

(Equation 2)

In the present invention, preferably, at least one compound represented by the following formula (S) is used as a compound capable of reacting with formaldehyde to fix the formaldehyde.

[0009]

Embedded image

[In the formula (S), X ¹ is an oxygen atom or ＮN
Represents an H group. R ¹ and R ² each independently represent a hydrogen atom, an acyl group, a hydrocarbon group or a carbamoyl group. However, when X ¹ is an oxygen atom, at least one of R ¹ and R ²
One is a hydrogen atom. L ¹ represents a divalent organic group necessary for forming a cyclic structure. ]

In the present invention, preferably, 50% by weight of the binder of the image forming layer containing photosensitive silver halide is used.
As the above, a polymer latex having a glass transition temperature of −30 ° C. to 40 ° C. is used. In the present invention, preferably, as a nucleating agent, a substituted alkene derivative represented by the following formula (1), a substituted isoxazole derivative represented by the following formula (2), and a specific acetal represented by the following formula (3) At least one compound selected from compounds is used.

[0012]

Embedded image

[In the formula (1), R ¹¹ , R ¹² and R
¹³ independently represent a hydrogen atom or a substituent;
Represents an electron-withdrawing group or a silyl group. In the formula (1), R ¹¹ and Z, R ¹² and R ¹³ , R ¹¹ and R ¹² , and R ¹³ and Z
May be bonded to each other to form a cyclic structure. In the formula (2), R ¹⁴ represents a substituent. In the formula (3), X and Y each independently represent a hydrogen atom or a substituent, and A and B each independently represent an alkoxy group, an alkylthio group, an alkylamino group, an aryloxy group, an arylthio group, an anilino group, a hetero group. Represents a ring oxy group, a heterocyclic thio group or a heterocyclic amino group. formula
In (3), X and Y, and A and B may be bonded to each other to form a cyclic structure. ]

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments and a method of the photothermographic material of the present invention will be described in detail. The photothermographic material of the present invention has, on at least one surface of a support, an image forming layer (that is, a photosensitive layer) containing a silver salt of an organic acid, a photosensitive silver halide and a binder as a non-photosensitive silver salt. And a layer on the support surface side where the image forming layer is present (hereinafter referred to as “layer on the image forming layer side”).
) Is a high contrast photosensitive material containing a nucleating agent. The present invention provides a photothermographic material which gives such a high contrast image, a compound which can react with formaldehyde such as a cyclic ketone or a cyclic imine compound represented by the formula (S) to fix the compound. , In a layer on the image forming layer side, whereby a change in photographic performance during storage can be suppressed. In the present invention, a layer containing a compound capable of reacting with formaldehyde and fixing the same is coated with a coating solution for 5 seconds from the start of drying until the water content reaches 200%. It is characterized in that it is formed by drying under the conditions of not more than 5 minutes, whereby the amount of the compound capable of reacting with formaldehyde and fixing it can be reduced, and Changes in photographic performance due to changes in storage conditions such as the environment can be reduced. Details of the drying conditions will be described later.

As the main binder of the image forming layer, it is preferable to use a polymer latex which can provide good photographic performance and enables water-based coating.
A latex of a polymer having a glass transition temperature of 0 ° C or more and 40 ° C or less is preferred. As a nucleating agent, it is preferable to use compounds represented by the formulas (1) to (3) (details will be described later) in order to obtain a harder image. As a compound (hereinafter, also referred to as formalin scavenger) which reacts with and fixes formaldehyde used in the present invention, any compound having such an action can be used. As used herein, the term "formaldehydes" is a general term for formaldehyde and its derivatives that have an adverse effect on photothermographic materials. As used herein, the term "fix" means that the compound binds to formaldehydes and does not affect the photographic properties during storage (especially, increase in fog). The type of formalin scavenger used in the present invention is not particularly limited,
Preferably, it is represented by the following formula (S).

[0016]

Embedded image

Hereinafter, the cyclic compound represented by the formula (S) will be described in more detail. R ¹ and R ² each independently represent a hydrogen atom, an acyl group, a hydrocarbon group or a carbamoyl group. As the hydrocarbon group, an alkyl group (including an aralkyl group) and an aryl group are preferable. Examples of the groups represented by R ¹ and R ² include a hydrogen atom, a substituted or unsubstituted acyl group having 1 to 10 carbon atoms (eg, acetyl and propionyl), and a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms (eg, , Methyl, ethyl, propyl, benzyl), carbon number 6
A substituted or unsubstituted aryl group (for example, phenyl, 4-ethoxyphenyl, naphthyl) or a substituted or unsubstituted carbamoyl group (for example, carbamoyl, N, N-dimethylcarbamoyl); An alkyl group of formulas 1 to 3 or a carbamoyl group is particularly preferred. Further, R ¹ and R ² are hydrocarbon groups, and the hydrocarbon group is a partial structure of a cyclic compound represented by the formula (S) (a group derived from the cyclic compound represented by the formula (S)). You may have. X ¹ represents an oxygen atom or an imino group (＝ NH). When X ¹ is an oxygen atom, at least one of R ¹ and R ² is a hydrogen atom.
The divalent group represented by L ¹ is a group of non-metallic atoms necessary for forming a nitrogen-containing heterocyclic structure, and may have a ring structure inside L ^1. A condensed ring may be formed together with a portion having the following structure.

[0018]

Embedded image

As L ¹ , for example, ethylene, trimethylene and those having the following structure are preferable.

[0020]

Embedded image

In the above examples of L ¹ , L ¹ may be substituted by a methyl group, an amino group, a ureido group, a methylene group (CH ₂ ) or the like. Examples of the cyclic compound represented by the formula (S) used in the present invention are shown below, but the present invention is not limited thereto.

[0022]

Embedded image

[0023]

Embedded image

[0024]

Embedded image

[0025]

Embedded image

[0026] These cyclic compounds are known in the art as inhibitors of photographic performance degradation due to formaldehyde gas. It is extremely interesting and difficult to predict that such compounds have shown remarkable effects on fog prevention and sensitivity fluctuation during storage in photothermographic materials, especially those using a nucleating agent described below. Met. Specific examples of this series of compounds are described in JP-A-61-73.
No. 150, No. 58-10738, No. 50-87028
And the like. These compounds are commercially available, for example, British Patent 717,287, U.S. Patent 2,731,472, 3,187,004
And JP-A-58-79248. In the present invention, one kind of the compound represented by the above formula (S) may be used, or two or more kinds thereof may be used in combination, or one kind of formalin scavenger other than the compound of the above formula (S) may be used. Even if you use more than that,
Alternatively, the compound of formula (S) may be used in combination with another formalin scavenger.

In the present invention, the layer containing at least one compound capable of reacting with formaldehyde and fixing the same is formed by rapidly drying the coating solution. The layer containing the compound is optional, and may be contained, for example, in a layer in which the effect of formaldehyde gases is to be prevented, in a layer adjacent to the layer, or in a layer located outside the layer. Specifically, a formalin scavenger is contained in at least one of a layer (for example, a protective layer) above the image forming layer, an image forming layer containing a silver halide emulsion, an intermediate layer, an undercoat layer, and other auxiliary layers. Let it. In order to add the formalin scavenger used in the present invention to these layers, it can be added as it is in a coating solution or dissolved in a solvent such as water or alcohol. The addition amount of the formalin scavenger is suitably 0.001 g to 1 g per 1 m ² of the photothermographic material, and 0.005 g
~ 0.5 g is particularly preferred.

Next, various aspects of coating and drying of the layer containing the formalin scavenger will be described. Each layer constituting the photothermographic material of the present invention, for example, after being applied by a coating method such as slide bead coating, curtain coating, extrusion coating, the coating liquid is pre-dried in the first drying zone to increase the viscosity, The flow is stopped, and it is further led to the second drying zone, where it undergoes constant rate drying, reduced rate drying, and humidity control to form a film (manufacturing).
Is done. Constant-rate drying refers to a drying process in which the amount of solvent evaporated per unit period, that is, the evaporation rate of the solvent is constant, and reduced-rate drying means that the evaporation rate of the solvent gradually decreases after constant-rate drying is completed. A drying process until almost no evaporation occurs (that is, the coating film has an equilibrium moisture content under conditions of temperature and humidity of outside air). As constant rate drying, the liquid film surface temperature at the time of drying is 25 ° C or more and 40 ° C or less,
In addition, it is preferable that the drying is performed at a dry-bulb temperature of 50 ° C. or higher and a glass transition temperature of the support used or lower. Here, the liquid film surface temperature refers to the solvent liquid film surface temperature when the coating liquid film applied to the support is dried at a constant rate, and the dry bulb temperature refers to the temperature of the drying air in the drying zone. Further, it is preferable to dry in a horizontal drying zone at least until the constant rate drying is completed.

The drying conditions in the practice of the present invention are such that the time from the start of drying to the point when the water content defined by the above formula reaches a water content near the critical water content of 200% or less is within 5 minutes. Condition, more preferably within 3 minutes, further preferably within 2 minutes. The drying time is 5 seconds or more from the viewpoint of manufacturing equipment, and is preferably 10 seconds or more from the viewpoint of increasing the viscosity of the coating solution. In the above formula, the coating layer on the support means each layer applied on the support, such as an image forming layer and a protective layer. By forming a layer containing a formalin scavenger under the above-described drying conditions, the amount of formalin scavenger added may be small, and furthermore, a photothermographic material having good formalin resistance and excellent film brittleness can be obtained. it can.

The photothermographic material of the present invention contains a non-photosensitive silver salt. The organic silver salt that can be used in the present invention is relatively stable to light, but can be used in the presence of an exposed photocatalyst (such as a latent image of a photosensitive silver halide) and a reducing agent.
It is a silver salt that forms a silver image when heated to a temperature of ℃ or more. The organic silver salt can be any organic substance including a source capable of reducing silver ions. Silver salts of organic acids, especially
Silver salts of long chain fatty carboxylic acids (with 10-30, preferably 15-28 carbon atoms) are preferred. Also preferred are organic or inorganic silver salt complexes in which the ligand has a complex stability constant in the range of 4.0 to 10.0. The silver donor material can preferably make up about 5-70% by weight of the imaging layer. Preferred organic silver salts include silver salts of organic compounds having a carboxyl group. Examples of these include, but are not limited to, silver salts of aliphatic carboxylic acids and silver salts of aromatic carboxylic acids. Preferred examples of the silver salt of an aliphatic carboxylic acid include silver behenate,
Silver arachidate, silver stearate, silver oleate, silver laurate, silver caproate, silver myristate, silver palmitate, silver maleate, silver fumarate, silver tartrate, silver linoleate, silver butyrate and silver camphorate, And mixtures thereof.

In the present invention, it is preferable to use silver behenate having a silver behenate content of 85 mol% or more, more preferably 95 mol% or more, of the above-mentioned organic silver salts or a mixture of the organic silver salts. . Here, the content of silver behenate indicates the molar fraction of silver behenate with respect to the organic acid silver used. As the organic acid silver other than silver behenate contained in the organic acid silver used in the present invention, those mentioned above can be preferably used. The silver salt of an organic acid preferably used in the present invention is prepared by reacting a silver nitrate solution with a solution or suspension of an alkali metal salt (including Na salt, K salt, Li salt and the like) of the organic acid described above. . The alkali metal salt of an organic acid is obtained by treating the above organic acid with an alkali. The silver organic acid can be run batchwise or continuously in any suitable vessel. The stirring in the reaction vessel can be performed by any stirring method depending on the required characteristics of the particles. As a method for preparing an organic acid silver salt, a method in which a silver nitrate aqueous solution is gradually or rapidly added to a reaction vessel containing an organic acid alkali metal salt solution or suspension,
A method in which a previously prepared organic acid alkali metal salt solution or suspension is gradually or rapidly added to a reaction vessel containing an aqueous silver nitrate solution, and a previously prepared silver nitrate aqueous solution and an organic acid alkali metal salt solution or suspension are added to the reaction vessel. Any of the methods of simultaneous addition into the inside can be preferably used.

The silver nitrate aqueous solution and the organic acid alkali metal salt solution or suspension may be of any concentration for controlling the particle size of the prepared organic acid silver, and may be added at any addition rate. Can be. The silver nitrate aqueous solution and the organic acid alkali metal salt solution or suspension can be added by a method of adding at a constant addition rate, an accelerated addition method by an arbitrary time function, or a deceleration addition method. Further, it may be added to the liquid surface or may be added to the reaction solution. In the case of a method in which a previously prepared aqueous silver nitrate solution and an organic acid alkali metal salt solution or suspension are simultaneously added to the reaction vessel, either the silver nitrate aqueous solution or the organic acid alkali metal salt solution or suspension is preceded. Although it can be added, it is preferable to add the silver nitrate aqueous solution in advance. The degree of precedence is preferably from 0 to 50 vol%, particularly preferably from 0 to 25 vol% of the total amount. As described in JP-A-9-127643, a method of adding while controlling the pH or silver potential of the reaction solution during the reaction can also be preferably used.

The pH of the aqueous silver nitrate solution or organic acid alkali metal salt solution or suspension to be added can be adjusted according to the required properties of the particles. An optional acid or alkali can be added for pH adjustment. Depending on the required characteristics of the particles, for example, the temperature in the reaction vessel can be set arbitrarily for controlling the particle size of the prepared organic acid silver salt. Alternatively, the suspension can also be adjusted to any temperature. The organic acid alkali metal salt solution or suspension is preferably heated and kept at 50 ° C. or higher in order to ensure fluidity of the solution.

The organic acid silver used in the present invention is preferably prepared in the presence of a tertiary alcohol. The tertiary alcohol preferably has a total carbon number of 15 or less, particularly preferably 10 or less. Preferred examples of the tertiary alcohol include tert-butanol, but the present invention is not limited thereto. The tertiary alcohol used in the present invention may be added at any time during the preparation of the organic acid silver salt, but it is preferable to add the tertiary alcohol during the preparation of the organic acid alkali metal salt and dissolve the organic acid alkali metal salt before use. . The amount of the tertiary alcohol can be arbitrarily used in a weight ratio of 0.01 to 10 with respect to water as a solvent at the time of preparing the silver salt of an organic acid, but is preferably in a range of 0.03 to 1.

The shape of the organic silver salt that can be used in the present invention is not particularly limited, but a needle crystal having a short axis and a long axis is preferable. In the present invention, the minor axis is 0.01 μm or more and 0.2 μm or more.
0 μm or less, major axis of 0.10 μm or more and 5.0 μm or less, minor axis of 0.01 μm or more and 0.15 μm or less, and major axis of 0.10 μm or more and 4.0 μm or less are more preferred. The particle size distribution of the organic silver salt is preferably monodispersed. Monodisperse is the standard deviation of the lengths of the minor and major axes divided by the minor and major axes, respectively.
0 fraction is preferably 100% or less, more preferably 80% or less,
More preferably, it is 50% or less. The shape of the organic silver salt can be measured from a transmission electron microscope image of the organic silver salt dispersion. As another method of measuring the monodispersity, there is a method of determining the standard deviation of the volume-weighted average diameter of the organic silver salt, the percentage of the value divided by the volume-weighted average diameter (coefficient of variation) is preferably 100% or less, more Preferably 80% or less,
More preferably, it is 50% or less. As a measuring method, for example, the particle size (volume weighted average diameter) obtained by irradiating a laser beam to an organic silver salt dispersed in a liquid and obtaining an autocorrelation function with respect to a time change of fluctuation of the scattered light is obtained. Can be. The organic silver salt that can be used in the present invention is preferably desalted. The method for desalting is not particularly limited, and a known method can be used. However, a known filtration method such as centrifugal filtration, suction filtration, ultrafiltration, or floc-forming water washing by a coagulation method can be preferably used.

In the present invention, in order to obtain an organic silver salt solid dispersion having a high S / N, a small particle size, and no aggregation, an organic silver salt which is an image forming medium and a photosensitive silver salt are substantially contained. It is preferable to use a dispersion method in which a water dispersion liquid which is not included in the liquid is converted into a high-speed stream and then the pressure is reduced. After passing through such a process, the mixture is mixed with a photosensitive silver salt aqueous solution to produce a photosensitive image forming medium coating solution. When a photothermographic material is prepared using such a coating solution, a haze is low, and a low-fogging, high-sensitivity photothermographic material can be obtained. On the other hand, when the photosensitive silver salt is coexistent when the light is converted into a high-pressure, high-speed flow and dispersed, the fog increases and the sensitivity is remarkably lowered. When an organic solvent is used instead of water as a dispersion medium, haze increases, fog increases, and sensitivity tends to decrease. On the other hand, when a conversion method for converting a part of the organic silver salt in the dispersion to the photosensitive silver salt is used instead of the method of mixing the aqueous solution of the photosensitive silver salt, the sensitivity is reduced. In the above, the high-pressure, the aqueous dispersion is dispersed and converted to high speed, is substantially free of photosensitive silver salt, the water content is 0.1 mol% based on the non-photosensitive organic silver salt The following is the case where the photosensitive silver salt is not positively added.

In the present invention, the solid dispersion apparatus and the technique used for carrying out the dispersion method as described above are described in, for example, “Dispersion Rheology and Dispersion Technique” (Toshio Kajiuchi and Hiroki Usui, 1991, Shinzansha Publishing Co., Ltd., p357
-P403), "The 24th Progress of Chemical Engineering", edited by The Society of Chemical Engineers, Tokai Branch, 1990, Maki Shoten, p184-p185),
Although detailed in the dispersing method of the present invention, the aqueous dispersion containing at least an organic silver salt is pressurized by a high-pressure pump or the like and sent into a pipe, and then passed through a narrow slit provided in the pipe, Thereafter, the dispersion is finely dispersed by causing an abrupt pressure drop in the dispersion. As for the high-pressure homogenizer to which the present invention is related, generally, (a) the dispersoid is released at a normal pressure from a high pressure under a high pressure, and `` shearing force '' generated when the dispersoid passes through a narrow gap at a high speed. It is considered that the particles are dispersed into fine particles by a dispersing force such as “cavitation force” generated when the particles are dispersed. As an example of this type of dispersing apparatus, a Gaulin homogenizer is mentioned in the past.In this apparatus, the liquid to be dispersed sent at a high pressure is converted into a high-speed flow through a narrow gap on a cylindrical surface, and the force is applied to the surrounding wall by the force. The particles collide and are emulsified and dispersed by the impact force. Operating pressure is generally 100~600kg / cm ^2, the number is the flow velocity m~3
It is in the range of 0 m / sec, and in order to increase the dispersion efficiency, a device in which the high flow velocity portion is saw-toothed and the number of collisions is increased has been devised. On the other hand, in recent years, devices capable of dispersing at higher pressure and higher flow rate have been developed,
Typical examples thereof include a microfluidizer (Microfluidex International Corporation) and a nanomizer (Special Kika Kogyo Co., Ltd.).

The dispersion apparatus suitable for carrying out the present invention includes:
Microfluidizer M-110S- manufactured by Microfluidex International Corporation
EH (with G10Z interaction chamber),
M-110Y (with H10Z interaction chamber), M-140K (with G10Z interaction chamber), HC-5000 (L30Z or H2
With 30Z interaction chamber), HC-8
000 (with an E230Z or L30Z interaction chamber) and the like. Using these devices, an aqueous dispersion containing at least an organic silver salt is pressurized by a high-pressure pump or the like and fed into a pipe, and then a desired pressure is applied by passing through a narrow slit provided in the pipe. After that, a sudden pressure drop is caused in the dispersion by, for example, rapidly returning the pressure in the pipe to the atmospheric pressure, whereby an organic silver salt dispersion optimal for the present invention can be obtained.
It is preferable that the raw material liquid is preliminarily dispersed before the dispersion operation. As means for preliminary dispersion, known dispersion means (for example, high-speed mixer, homogenizer, high-speed impact mill, Banbury mixer, homomixer, kneader, ball mill, vibration ball mill, planetary ball mill, attritor,
Sand mills, bead mills, colloid mills, jet mills, roller mills, tron mills, high-speed stone mills) can be used. Instead of mechanically dispersing, fine particles may be formed by coarsely dispersing in a solvent by controlling the pH and then changing the pH in the presence of a dispersing agent.
At this time, an organic solvent may be used as a solvent used for the coarse dispersion, and the organic solvent is usually removed after the completion of the fine particle formation.

In the organic silver salt dispersion, it is possible to obtain a desired particle size by adjusting the flow rate, the differential pressure at the time of pressure drop, and the number of processings. / Sec to 600m / sec, the differential pressure during pressure drop
Is preferably in the range of 900~3000kg / cm ^2, the flow rate is 300 meters / sec to 60
More preferably, the pressure difference at the time of 0 m / sec and the pressure drop is in the range of 1500 to 3000 kg / cm ² . The number of times of dispersion processing can be selected as needed, but usually 1 to 10 times is selected, but from the viewpoint of productivity, about 1 to 3 times is selected. Heating such aqueous dispersions under high pressure is
At a high temperature exceeding 90 ° C., the particle size tends to increase and fog tends to increase. Therefore, in the present invention, the step before the conversion to the high pressure and high flow rate, the step after the pressure is reduced, or both of these steps include a cooling step, and the temperature of such water dispersion is reduced by the cooling step.
The temperature is preferably maintained in the range of 90 to 90 ° C, more preferably in the range of 5 to 80 ° C, particularly preferably in the range of 5 to 65 ° C. In particular, it is effective to provide the above cooling step at the time of high-pressure dispersion in the range of 1500 to 3000 kg / cm ² . As the cooler, a double tube, a double tube using a static mixer, a multi-tube heat exchanger, a coiled tube heat exchanger, or the like can be appropriately selected according to the required heat exchange amount. Further, in order to increase the efficiency of heat exchange, it is sufficient to select a suitable one such as a pipe thickness, a wall thickness and a material in consideration of a working pressure. As the refrigerant used for the cooler, use 20 ° C well water, 5-10 ° C cold water treated with a refrigerator, and, if necessary, -30 ° C ethylene glycol / water refrigerant, etc., based on the heat exchange amount. You can also.

In the dispersion operation in the present invention, the average degree of polymerization is
The organic silver salt is dispersed in the presence of 1000 to 2500 polyvinyl alcohol. Details of polyvinyl alcohol are described in, for example, "Poval" (Koichi Nagano, Saburo Yamane, Kentaro Toshima, 1981, Kobunshi Kanko-kai). Examples of the polyvinyl alcohol preferably used in the present invention include, for example, Poval PVA manufactured by Kuraray Co., Ltd.
-217, PVA-117, and PVA-420. The amount of polyvinyl alcohol used at the time of dispersion of the organic silver salt can be used in a weight ratio of 1:50 to 1: 1 with respect to the organic silver salt, but is preferably in a range of 1:25 to 1: 5. It is. In the dispersion operation in the practice of the present invention, it is preferable to disperse the organic silver salt in the presence of an aqueous solvent-soluble dispersant (dispersion aid). Examples of the dispersing agent include polyacrylic acid, a copolymer of acrylic acid, a maleic acid copolymer, a maleic acid monoester copolymer, a synthetic anionic polymer such as an acrylomethylpropanesulfonic acid copolymer, and carboxymethyl. Starch, semi-synthetic anionic polymers such as carboxymethyl cellulose, alginic acid, anionic polymers such as pectic acid, the compounds described in JP-A-7-350753, or known anionic, nonionic, cationic surfactants and other polyvinyl Known polymers such as alcohol, polyvinylpyrrolidone, carboxymethylcellulose, hydroxypropylcellulose and hydroxypropylmethylcellulose, or naturally occurring polymer compounds such as gelatin can be appropriately selected and used. Le compounds, particularly preferred water-soluble cellulose derivatives.

It is a general method to mix a dispersion aid with an organic silver salt powder or an organic silver salt in a wet cake state before dispersion, and to send it as a slurry to a dispersing machine. Heat treatment or treatment with a solvent may be performed in the combined state to obtain an organic silver salt powder or a wet cake. The pH may be controlled by a suitable pH adjuster before, during or after dispersion. In addition to mechanical dispersion, pH
By performing control, the particles may be roughly dispersed in a solvent, and then the pH may be changed in the presence of a dispersing agent to form fine particles. At this time, an organic solvent may be used as a solvent used for the coarse dispersion, and the organic solvent is usually removed after the completion of the fine particle formation. The prepared dispersion is stored with stirring for the purpose of suppressing sedimentation of fine particles during storage, or stored in a highly viscous state by a hydrophilic colloid (for example, in a jelly state using gelatin). You can also. Further, a preservative can be added for the purpose of preventing the propagation of various bacteria during storage.

The particle size (volume-weighted average diameter) of the organic silver salt solid fine particle dispersion used in the present invention is determined, for example, by irradiating a solid fine particle dispersion dispersed in a liquid with a laser beam and changing the fluctuation of the scattered light with time. Can be determined from the particle size (volume-weighted average diameter) obtained by calculating the autocorrelation function for. Average particle size 0.05μm or more 10.0μ
m or less is preferable. The average particle size is more preferably 0.1 μm or more and 5.0 μm or less, and still more preferably the average particle size is 0.1 μm or more and 2.0 μm or less. The particle size distribution of the organic silver salt is preferably monodispersed.
Specifically, the percentage (coefficient of variation) of the value obtained by dividing the standard deviation of the volume-weighted average diameter by the volume-weighted average diameter is 80% or less, more preferably 50% or less, and still more preferably 30% or less. The shape of the organic silver salt can be measured from a transmission electron microscope image of the organic silver salt dispersion.

The organic silver salt solid fine particle dispersion used in the present invention comprises at least an organic silver salt and water. The ratio of the organic silver salt to water is not particularly limited, but the ratio of the organic silver salt to the whole is preferably 5 to 50% by weight, and more preferably 10 to 30% by weight.
It is preferable to use the above-mentioned dispersing aid, but it is preferable to use the dispersing aid in a minimum amount within a range suitable for minimizing the particle size, and 0.5 to 30% by weight, especially 1 to 30% by weight based on the organic silver salt.
A range of 15% by weight is preferred. In the present invention, it is possible to produce a photosensitive material by mixing the organic silver salt aqueous dispersion and the photosensitive silver salt aqueous dispersion, the mixing ratio of the organic silver salt and the photosensitive silver salt can be selected according to the purpose, The ratio of the photosensitive silver salt to the organic silver salt is preferably in the range of 1 to 30 mol%, more preferably 3 to 30 mol%.
A range of 20 mol%, especially 5 to 15 mol% is preferred. Mixing two or more aqueous dispersions of organic silver salts with two or more aqueous dispersions of photosensitive silver salts during mixing is a method preferably used for adjusting photographic characteristics. The organic silver salt in the present invention can be used in a desired amount, if indicated by the coating amount per the photosensitive material 1 m ^2, preferably 0.1-5 g / m ² as silver amount, more preferably is 1 to 3 g / m ² .

In the present invention, it is preferable to add a metal ion selected from Ca, Mg, Zn and Ag to the non-photosensitive organic silver salt. Regarding the addition of a metal ion selected from Ca, Mg, Zn and Ag to the non-photosensitive organic silver salt,
It is preferably added in the form of a water-soluble metal salt that is not a halide, and specifically, it is preferably added in the form of a nitrate or a sulfate. The addition of a halide is not preferred because it deteriorates the image storability of the processed photosensitive material due to light (such as room light or sunlight), that is, the so-called printout property. For this reason, in the present invention, it is preferable to add in the form of a water-soluble metal salt which is not the above-mentioned halide. The addition time of the metal ion selected from Ca, Mg, Zn and Ag preferably used in the present invention is, for example, after the particle formation of the non-photosensitive organic silver salt, immediately before the particle formation, before the dispersion, after the dispersion and before and after the preparation of the coating solution. The timing may be any time as long as immediately before the coating, preferably after the dispersion and before and after the preparation of the coating solution. In the present invention, the addition amount of the metal ion selected from Ca, Mg, Zn and Ag may be selected from non-photosensitive organic silver.
It is preferably 10 ^-3 to 10 ^-1 mol per mol, particularly 5 × 10 ^-3 to ¹ mol.
5 × 10 ^-2 mol is preferred.

The photothermographic material of the present invention contains a photosensitive silver halide. The photosensitive silver halide used in the present invention is not particularly limited as a halogen composition, and silver chloride, silver chlorobromide, silver bromide, silver iodobromide, and silver iodochlorobromide can be used. The distribution of the halogen composition in the grains may be uniform, the halogen composition may change stepwise, or may change continuously. Further, silver halide grains having a core / shell structure can be preferably used. The structure is preferably 2-
Core / shell particles having a quintuple structure, more preferably a quintuple structure, can be used. A technique for localizing silver bromide on the surface of silver chloride or silver chlorobromide grains can also be preferably used. Methods for forming light-sensitive silver halide are well known in the art, for example, Research Disclosure No. 17029, June 1978, and U.S. Pat.
The method described in No. 8 can be used, but specifically, a photosensitive silver halide is prepared by adding a silver supply compound and a halogen supply compound to gelatin or another polymer solution, and thereafter, A method of mixing with an organic silver salt is used. The grain size of the photosensitive silver halide is preferably small for the purpose of suppressing the white turbidity after image formation, specifically, 0.20 μm or less, more preferably 0.01 μm or more and 0.15 μm or less, and still more preferably 0.02 μm or more. 0.12 μm or less is preferred. Here, the grain size means the length of the edge of the silver halide grain when the silver halide grain is a cubic or octahedral so-called normal crystal.
In the case where the silver halide grains are tabular grains, the diameter refers to a diameter when converted into a circular image having the same area as the projected area of the main surface. In the case of other than normal crystals, for example, in the case of spherical grains, rod-like grains, etc., it refers to the diameter of a sphere equivalent to the volume of silver halide grains.

The shape of the silver halide grains is cubic,
Octahedral, tabular particles, spherical particles, rod-like particles, potato-like particles and the like can be mentioned. In the present invention, cubic particles and tabular particles are particularly preferable. When tabular silver halide grains are used, the average aspect ratio is preferably 100: 1 to 2: 1, more preferably 50: 1 to 3: 1. Further, grains having rounded corners of silver halide grains can also be preferably used. The surface index (mirror index) of the outer surface of the photosensitive silver halide grain is not particularly limited, but the spectral sensitization efficiency when the spectral sensitizing dye is adsorbed is high.
The proportion occupied by the [100] plane is preferably high. The ratio is preferably 50% or more, more preferably 65% or more,
80% or more is more preferable. The Miller index [100] plane ratio was determined by T. Tani; J. Imaging Sci., 29, 165 (1985), which utilizes the adsorption dependence of [111] and [100] planes on the adsorption of sensitizing dyes. It can be determined by the method described. The photosensitive silver halide grains used in the present invention contain a metal or a metal complex of Group VII or VIII (Groups 7 to 10) of the periodic table. Preferably rhodium as the central metal of the metal or metal complex of Group VII or VIII of the Periodic Table,
Rhenium, ruthenium, osmium, and iridium. One type of these metal complexes may be used, or two or more types of complexes of the same metal and different metals may be used in combination. The preferred content is 1 × 10 ⁻⁹ mol to 1 × 10 ⁻³ mol per mol of silver.
The molar range is preferably 1 × 10 ⁻⁸ mol to 1 × 10 ⁻⁴ mol.
A molar range is more preferred. As a specific structure of the metal complex, a metal complex having a structure described in JP-A-7-225449 or the like can be used.

As the rhodium compound used in the present invention, a water-soluble rhodium compound can be used. For example, a rhodium (III) halide compound or a rhodium complex salt having a ligand such as halogen, amines, oxalato, etc., for example, hexachlororhodium (II)
I) Complex salts, pentachloroacolodium (III) complex salts, tetrachlorodiachodium (III) complex salts, hexabromorhodium (III) complex salts, hexaamminerhodium (III) complex salts, trioxalathrodium (III) complex salts, and the like. Can be These rhodium compounds are used by dissolving them in water or a suitable solvent. A method generally used for stabilizing a solution of the rhodium compound is generally used, that is, an aqueous solution of hydrogen halide (eg, hydrochloric acid, hydrobromic acid, hydrofluoric acid) Etc.) or alkali halides (eg KCl, NaC
l, KBr, NaBr, etc.) can be used. Instead of using water-soluble rhodium, it is also possible to add and dissolve other silver halide grains doped with rhodium during the preparation of silver halide. The addition amount of these rhodium compounds is preferably in the range of 1 × 10 ⁻⁸ mol to 5 × 10 ⁻⁴ mol per mol of silver halide,
Particularly preferably, it is 5 × 10 ⁻⁸ mol to 1 × 10 ⁻⁵ mol. These compounds can be appropriately added at the time of the production of silver halide emulsion grains and at each stage before coating the emulsion, but it is particularly preferable to add them at the time of emulsion formation and incorporate them into the silver halide grains. .

Rhenium, ruthenium and osmium used in the present invention are described in JP-A-63-2042, JP-A-1-285941,
It is added in the form of a water-soluble complex salt described in JP-A Nos. 2-20852 and 2-20855. Particularly preferred is a six-coordinate complex represented by the following formula. [ML ₆ ] ⁿ -where M represents Ru, Re, or Os, L represents a ligand, and n represents 0, 1, 2, 3, or 4. In this case, the counter ion is not important and ammonium or alkali metal ions are used. Preferred ligands include halide ligands, cyanide ligands, cyanide ligands, nitrosyl ligands, thionitrosyl ligands, and the like. Examples of specific complexes used in the present invention are shown below, but the present invention is not limited thereto.

[ReCl ₆ ] ^3- [ReBr ₆ ] ^3- [ReCl ₅ (NO)] ^2- [Re (NS) Br ₅ ] ^2- [Re (NO) (CN) ₅ ] ^2- [Re (O ) ₂ (CN) ₄ ] ^3- [RuCl ₆ ] ^3- [RuCl ₄ (H ₂ O) ₂ ] ^- [RuCl ₅ (H ₂ O)] ^2- [RuCl ₅ (NO)] ^2- [RuBr ₅ ( NS)] ^2- [Ru (CO) ₃ Cl ₃ ] ^2- [Ru (CO) Cl ₅ ] ^2- [Ru (CO) Br ₅ ] ^2- [OsCl ₆ ] ^3- [OsCl ₅ (NO)] ^{2 -} [Os (NO) (CN) ₅ ] ^2- [Os (NS) Br ₅ ] ^2- [Os (O) ₂ (CN) ₄ ] ^4-

The addition amount of these compounds is 1
1 × 10 per mole^-9Mol ~ 1 x 10 ^-FourMolar range preferred
And particularly preferably 1 × 10^-8Mol ~ 1 x 10^-FiveMole
It is. The addition of these compounds was
Suitable during the manufacture of the emulsion and at each stage before the application of the emulsion.
However, it may be added at the time of forming an emulsion,
It is preferably incorporated into silver gemide grains. these
Is added during the formation of silver halide grains,
For incorporation into silver halide particles, powder of metal complex or
The aqueous solution dissolved with NaCl and KCl is mixed with water during particle formation.
How to add to soluble salt or water-soluble halide solution
Method, or when silver salt and halide solution are mixed at the same time
And added as a third solution.
It is necessary to prepare silver
How to add the required amount of metal complex aqueous solution to the reaction vessel
There is. Especially dissolved with powder or NaCl, KCl
The method of adding an aqueous solution to a water-soluble halide solution is preferred.
No. To add to the particle surface, immediately after particle formation or physically
During ripening, at the end, or during chemical ripening,
An aqueous solution of the metal complex can also be charged into the reaction vessel.

Various compounds can be used as the iridium compound used in the present invention, and examples thereof include hexachloroiridium, hexaammineiridium, trioxalatoiridium, hexacyanoiridium, and pentachloronitrosyliridium. These iridium compounds are used after being dissolved in water or a suitable solvent. However, a method generally used for stabilizing a solution of the iridium compound, that is, an aqueous solution of hydrogen halide (for example, hydrochloric acid, hydrobromic acid, hydrofluoric acid) is used. Etc.) or a method of adding an alkali halide (eg, KCl, NaCl, KBr, NaBr, etc.). Instead of using water-soluble iridium, it is also possible to add and dissolve another iridium-doped silver halide grain during silver halide preparation.

The silver halide grains used in the present invention may further include cobalt, iron, nickel, chromium, palladium,
It may contain metal atoms such as platinum, gold, thallium, copper and lead. For compounds of cobalt, iron, chromium, and ruthenium, hexacyano metal complexes can be preferably used. Specific examples include ferricyanate ion, ferrocyanate ion, hexacyanocobaltate ion,
Examples include, but are not limited to, hexacyanochromate ions, hexacyanoruthenate ions, and the like. The phase containing the metal complex in the silver halide may be uniform, may be contained at a high concentration in the core portion, or may be contained at a high concentration in the shell portion, and there is no particular limitation. The metal is 1 × 10 ^-9 to 1 × 10 per mol of silver halide.
^-4 mol is preferred. In addition, in order to incorporate the metal, a metal salt in the form of a single salt, a double salt, or a complex salt can be added at the time of preparing particles.

The photosensitive silver halide grains can be desalted by washing with water by a method known in the art, such as a noodle method or flocculation method, but in the present invention, it may or may not be desalted. . As a gold sensitizer used for performing gold sensitization on a silver halide emulsion, the oxidation number of gold is +1.
Valence or +3 valence, and a gold compound usually used as a gold sensitizer can be used. Representative examples include chloroauric acid, potassium chloroaurate, auric trichloride, potassium auric thiocyanate, potassium iodooleate, tetracyano auric acidide, ammonium aurothiocyanate, pyridyl trichlorogold and the like. The addition amount of the gold sensitizer may vary depending on various conditions, per mol of silver halide 10 ^-7 mol to 10 ^-3 mol or less as a guide, more preferably 1
0 ^-6 mol to 5 × is 10 ^-4 or less.

The silver halide emulsion used in the present invention is preferably used in combination with gold sensitization and another chemical sensitization. As other chemical sensitization methods, known methods such as a sulfur sensitization method, a selenium sensitization method, a tellurium sensitization method, and a noble metal sensitization method can be used. When used in combination with gold sensitization, for example, sulfur sensitization and gold sensitization, selenium sensitization and gold sensitization, sulfur sensitization and selenium sensitization and gold sensitization, Sulfur sensitization, tellurium sensitization, and gold sensitization, and sulfur sensitization, selenium sensitization, tellurium sensitization, and gold sensitization are preferred. The sulfur sensitization preferably used in the present invention is usually carried out by adding a sulfur sensitizer and stirring the emulsion at a high temperature of 40 ° C. or higher for a certain time. As the sulfur sensitizer, known compounds can be used.For example, in addition to sulfur compounds contained in gelatin, various sulfur compounds such as thiosulfates, thioureas, thiazoles, rhodanines and the like are used. be able to. Preferred sulfur compounds are thiosulfates and thiourea compounds. The amount of the sulfur sensitizer to be added varies under various conditions such as pH during chemical ripening, temperature, and the size of silver halide grains, but is preferably 10 ^-7 to 10 ^-2 mol per mol of silver halide. And more preferably 10 ^-5 or more.
10 ^-3 mol.

As the selenium sensitizer used in the present invention, known selenium compounds can be used. That is, it is usually carried out by adding an unstable and / or non-unstable selenium compound and stirring the emulsion at a high temperature of 40 ° C. or higher for a certain time. As unstable selenium compounds, JP-B-44-15748, JP-B-43-13489, JP-A-4-25832,
The compounds described in JP-A Nos. 4-109240, 3-21798 and the like can be used. In particular, it is preferable to use the compounds represented by formulas (VIII) and (IX) in JP-A-4-324855. The tellurium sensitizer used in the present invention is a compound which forms silver telluride which is presumed to be a sensitizing nucleus on the surface or inside of silver halide grains. The formation rate of silver telluride in the silver halide emulsion can be tested by the method described in JP-A-5-313284. Examples of tellurium sensitizers include diacyl tellurides, bis (oxycarbonyl) tellurides, bis (carbamoyl) tellurides, diacyl tellurides, bis (oxycarbonyl) ditellurides, bis (carbamoyl) ditellurides, P = Te A compound having a bond,
Tellurocarboxylates, Te-organyltellurocarboxylates, di (poly) tellurides, tellurides, tellurols, telluroacetals, tellurosulfonates, compounds having a P-Te bond, Te-containing heterocycles, Tellurocarbonyl compounds, inorganic tellurium compounds, colloidal tellurium, and the like can be used. Specifically, U.S. Patent Nos. 4-20464
0, 3-53693, 3-31598, 4-129787, Journal of Chemical Society Chemical Communication (J.Chem.Soc.Chem.Commun.) 635 (198
0), ibid 1102 (1979), ibid 645 (1979), Journal of Chemical Society Parkin Transaction (J. Chem. Soc. Perkin. Trans.) 1, 2191 (1980), S.
Edited by S. Patai, The Chemistry of Organic Serenium and Telluniu
m Compounds), Vol 1 (1986) and Vol. 2 (1987). In particular, compounds represented by formulas (II), (III) and (IV) in JP-A-5-313284 are preferred.

The amount of the selenium and tellurium sensitizers used in the present invention varies depending on the silver halide grains to be used, the conditions of chemical ripening, and the like, but is generally 10 ^-8 to 10 ^-2 mol per mol of silver halide. Preferably about 10 ^-7 to 10 ^-3 mol is used. The conditions of the chemical sensitization in the present invention are not particularly limited, but the pH is 5 to 8, the pAg is 6 to 11, preferably 7 to 10, and the temperature is 40 to 95 ° C, preferably 45 to 45 ° C. 85 ° C. In the silver halide emulsion used in the present invention, a cadmium salt, a sulfite, a lead salt, a thallium salt, and the like may coexist in the process of forming silver halide grains or physical ripening. In the present invention, reduction sensitization can be used. As specific compounds of the reduction sensitization method, in addition to ascorbic acid and thiourea dioxide, for example, stannous chloride, aminoiminomethanesulfinic acid, hydrazine derivatives, borane compounds, silane compounds, polyamine compounds and the like can be used. . Reduction sensitization can be achieved by ripening the emulsion while maintaining the pH of the emulsion at 7 or more or the pAg at 8.3 or less. Further, reduction sensitization can be achieved by introducing a single addition portion of silver ion during grain formation. A thiosulfonic acid compound may be added to the silver halide emulsion used in the present invention by a method described in European Patent Publication No. 293,917.

The silver halide emulsion in the light-sensitive material used in the present invention may be only one kind or two or more kinds (for example,
Those with different average grain sizes, different halogen compositions, different crystal habits, different chemical sensitization conditions)
You may use together. The amount of the photosensitive silver halide to be used is preferably 0.01 mol or more and 0.5 mol or less, more preferably 0.02 mol or more and 0.3 mol or less, particularly preferably 0.03 mol or more and 0.25 mol or less, based on 1 mol of the organic silver salt. preferable. Regarding the mixing method and the mixing conditions of the separately prepared photosensitive silver halide and organic silver salt, the prepared silver halide particles and organic silver salt were mixed with a high-speed stirrer, a ball mill, a sand mill, a colloid mill, a vibration mill, and a homogenizer. And the like, or a method of preparing an organic silver salt by mixing photosensitive silver halide prepared at any timing during the preparation of the organic silver salt. There is no particular limitation as long as it appears in.

As the sensitizing dye used in the present invention, any sensitizing dye can be used as long as it can spectrally sensitize the silver halide grains in a desired wavelength region when adsorbed on the silver halide grains. As the sensitizing dye, a cyanine dye, a merocyanine dye, a complex cyanine dye, a complex merocyanine dye, a holo-holerocyanine dye, a styryl dye, a hemicyanine dye, an oxonol dye, a hemioxonol dye, and the like can be used. Useful sensitizing dyes for use in the present invention include, for example, RESEARCH DISCLOSURE Item 17
Item 643IV-A (p.23, December 1978), Item 1831X (August 1979)
p.437) or in the literature cited. In particular, a sensitizing dye having a spectral sensitivity suitable for the spectral characteristics of the light source of various laser imagers, scanners, imagesetters and plate making cameras can be advantageously selected. Examples of spectral sensitization to red light, He-Ne laser, for a so-called red light source such as red semiconductor laser and LED, the I-1 to I-38 described in JP-A-54-18726 Compound, compounds of I-1 to I-35 described in JP-A-6-75322 and compounds of I-1 to I-34 described in JP-A-7-287338, dyes described in JP-B-55-39818 1 to 20, JP-A-62-2
Compounds of I-1 to I-37 described in 284343 and JP-A-7-2
Compounds I-1 to I-34 described in 87338 are advantageously selected.

For a semiconductor laser light source in the wavelength region of 750 to 1400 nm, cyanine, merocyanine, styryl,
A variety of known dyes, including hemicyanine, oxonol, hemioxonol and xanthene dyes, can be spectrally sensitized favorably. Useful cyanine dyes are, for example, cyanine dyes having a basic nucleus, such as a thiazoline nucleus, an oxazoline nucleus, a pyrroline nucleus, a pyridine nucleus, an oxazole nucleus, a thiazole nucleus, a selenazole nucleus and an imidazole nucleus. Preferred useful merocyanine dyes include, in addition to the above basic nuclei, acidic nuclei such as thiohydantoin nucleus, rhodanine nucleus, oxazolidinedione nucleus, thiazolinedione nucleus, barbituric acid nucleus, thiazolinone nucleus, malononitrile nucleus and pyrazolone nucleus. Including. Among the above-mentioned cyanine and merocyanine dyes, those having an imino group or a carboxyl group are particularly effective. For example, U.S. Pat.
3,719,495, 3,877,943, British Patent 1,466,201,
No. 1,469,117, No. 1,422,057, No. 3-10391, No. 6
-52387, JP-A-5-341432, JP-A-6-94781, JP-A-6-3011
The dye may be appropriately selected from known dyes as described in No. 41.

Particularly preferred as the structure of the dye used in the present invention is a cyanine dye having a thioether bond-containing substituent (see, for example, JP-A Nos. 62-58239 and 3-13863).
No.8, No.3-138642, No.4-255840, No.5-72659, No.5-
No. 72661, No. 6-222491, No. 2-230506, No. 6-258757
No., 6-317868, 6-324425, Tokuyohei 7-500926,
Dyes described in U.S. Pat.No. 5,541,054), dyes having a carboxylic acid group (for example, JP-A-3-163440, 6-30114
No. 1, U.S. Pat.No. 5,441,899), merocyanine dyes, polynuclear merocyanine dyes and polynuclear cyanine dyes
(JP 47-6329, JP 49-105524, JP 51-127719, JP
52-80829, 54-61517, 59-214846, 60-6750
No. 63-159841, JP-A-6-35109, JP-A-6-59381,
And the dyes described in JP-A-7-146537, JP-A-7-146537, JP-T-55-50111, British Patent 1,467,638, and US Patent 5,281,515. Further, as a dye forming a J-band, U.S. Pat.No. 5,510,236, the dye described in Example 5 of 3,871,887, JP-A-2-96131, JP-A-59-48753 are disclosed, and are preferably used in the present invention. Can be used.

These sensitizing dyes may be used alone,
Two or more kinds may be used in combination. Combinations of sensitizing dyes are often used, especially for supersensitization. In addition to the sensitizing dye, the emulsion may contain a dye which does not itself have a spectral sensitizing effect or a substance which does not substantially absorb visible light and exhibits supersensitization. Useful sensitizing dyes, combinations of dyes exhibiting supersensitization and substances exhibiting supersensitization are
Research Disclosure Volume 176, 17643 (Issued December 1978) No. 23
Section IV on page IV, or JP-B-49-25500, 43-43933,
These are described in JP-A-59-19032 and JP-A-59-192242. In order to add a sensitizing dye to a silver halide emulsion,
They may be dispersed directly in the emulsion, or
Methanol, ethanol, propanol, acetone, methylcellosolve, 2,2,3,3-tetrafluoropropanol, 2,2,2-trifluoroethanol, 3-methoxy-1-propanol, 3-methoxy-1-butanol, 1-methoxy-2-
A solvent such as propanol and N, N-dimethylformamide alone or in a mixed solvent may be added to the emulsion.

As disclosed in US Pat. No. 3,469,987, a dye is dissolved in a volatile organic solvent, this solution is dispersed in water or a hydrophilic colloid, and this dispersion is dispersed in an emulsion. Method of adding to Japanese Patent Publication No. 44-23389,
As disclosed in JP-A-44-27555 and JP-A-57-22091, the dye is dissolved in an acid and this solution is added to the emulsion, or an acid or base is added to the emulsion as an aqueous solution in the presence of an acid or base. A method of adding an aqueous solution or a colloidal dispersion in the presence of a surfactant to an emulsion, as disclosed in U.S. Patent Nos. 3,822,135 and 4,006,025, JP-A-53-102733. JP-A-51-746, a method in which a dye is directly dispersed in a hydrophilic colloid and the dispersion is added to an emulsion as disclosed in JP-A-58-105141.
As disclosed in Japanese Patent No. 24, a method in which a dye is dissolved using a compound that causes a red shift, and this solution is added to an emulsion can also be used. Also, ultrasonic waves can be used for dissolution.

The sensitizing dye may be added to the silver halide emulsion at any time during the preparation of the emulsion which has been found to be useful. US Patent
2,735,766, 3,628,960, 4,183,756, 4,22
No. 5,666, JP-A-58-184142, JP-A-60-196749, etc., as disclosed in the silver halide grain forming step or / and the time before the desalting, during the desalting step and / or during the desalting step. Alternatively, from the time after desalination to before the start of chemical ripening,
As disclosed in the specification such as -113920, the timing immediately before or during chemical ripening, at any time after the chemical ripening and before coating, the emulsion is added at any time during the process. Is also good. Also, U.S. Patent 4,225,666
As disclosed in the specification such as JP-A-58-7629, the same compound may be used alone or in combination with a compound having a different structure, for example, during the particle forming step and during the chemical ripening step or when the chemical ripening is completed. May be added separately, such as before or after chemical ripening or during the process and after completion, or may be added by changing the type of compound and compound combination to be added and divided. Good. The amount of the sensitizing dye used in the present invention may be a desired amount in accordance with the performance such as sensitivity and fog, but is preferably 10 ^-6 to 1 mol, more preferably 10 ^-4 to 1 mol per mol of silver halide in the photosensitive layer. 10 ^-1 mol is more preferred.

In the present invention, a supersensitizer can be used in order to improve the infrared spectral sensitization efficiency. The supersensitizers used in the present invention are disclosed in EP 587338, U.S. Pat. , Hydrazine,
Examples include compounds selected from triazines. Particularly preferred supersensitizers are heteroaromatic mercapto compounds and heteroaromatic disulfide compounds disclosed in JP-A-5-341432, stilbene compounds disclosed in JP-A-10-73899, and Japanese Patent Application No. 10-73899. General formula (I) described in -78168
Specifically, compound 1 described in the publication
~ 57. The supersensitizer such as a mercapto compound may be added in an amount of 0.001 mol per mol of silver in the emulsion layer.
The range is preferably from 01 to 1.0 mole, more preferably from 0.001 to 0.3 mole per mole of silver. Specific examples of the mercapto compound include those described below.

The photothermographic material of the present invention contains a nucleating agent.
Although the type of the nucleating agent used in the present invention is not particularly limited, for example, a substituted alkene derivative, a substituted isoxazole derivative and a specific acetal compound are preferable, and compounds represented by the following formulas (1) to (3) are more preferable. preferable.
Hereinafter, the substituted alkene derivative represented by the formula (1), the substituted isoxazole derivative represented by the formula (2), and the specific acetal compound represented by the formula (3) will be described.

[0066]

Embedded image

In the formula (1), R ¹¹ , R ¹² and R ¹³ each independently represent a hydrogen atom or a substituent, and Z represents an electron-withdrawing group or a silyl group. In the formula (1), R ¹¹ and Z,
R ¹² and R ¹³ , R ¹¹ and R ¹² , or R ¹³ and Z may be bonded to each other to form a cyclic structure. In the formula (2), R ¹⁴ represents a substituent. In the formula (3), X and Y each independently represent a hydrogen atom or a substituent, and A and B each independently represent an alkoxy group, an alkylthio group, an alkylamino group, an aryloxy group, an arylthio group, an anilino group, and a hetero group. Represents a ring oxy group, a heterocyclic thio group or a heterocyclic amino group. In equation (3), X and Y or A
And B may combine with each other to form a cyclic structure.

The compound represented by the formula (1) will be described in detail. In the formula (1), R ¹¹ , R ¹² and R ¹³ each independently represent a hydrogen atom or a substituent, and Z represents an electron-withdrawing group or a silyl group. In the formula (1), R ¹¹ and Z, R ¹²
And R ¹³ , R ¹¹ and R ¹² , or R ¹³ and Z may be bonded to each other to form a cyclic structure. R ¹¹ , R ¹² , R ¹³
When represents a substituent, examples of the substituent include, for example, a halogen atom (a fluorine atom, a chloro atom, a bromine atom, or an iodine atom), an alkyl group (including an aralkyl group, a cycloalkyl group, and an active methine group); Alkenyl group, alkynyl group, aryl group, heterocyclic group (including an N-substituted nitrogen-containing heterocyclic group), heterocyclic group containing a quaternized nitrogen atom (eg, pyridinio group), acyl group, alkoxycarbonyl group An aryloxycarbonyl group, a carbamoyl group, a carboxy group or a salt thereof, an imino group, an imino group substituted with an N atom, a thiocarbonyl group, a sulfonylcarbamoyl group, an acylcarbamoyl group, a sulfamoylcarbamoyl group, a carbazoyl group, an oxalyl group, Oxamoyl group, cyano group, thiocarbamoyl group, hydroxy group (or salt thereof) An alkoxy group (including a group containing a repeating ethyleneoxy or propyleneoxy group unit), an aryloxy group, a heterocyclic oxy group, an acyloxy group, a (alkoxy or aryloxy) carbonyloxy group, a carbamoyloxy group, a sulfonyloxy group, an amino Group, (alkyl, aryl, or heterocycle) amino group, acylamino group, sulfonamide group, ureido group, thioureido group, imide group, (alkoxy or aryloxy) carbonylamino group, sulfamoylamino group, semicarbazide group, thio Semicarbazide group, hydrazino group, quaternary ammonium group, oxamoylamino group, (alkyl or aryl) sulfonyluleide group, acylureide group, acylsulfamoylamino group, nitro group, mercapto group Is a salt thereof, an (alkyl, aryl, or heterocycle) thio group, an acylthio group, an (alkyl or aryl) sulfonyl group, an (alkyl or aryl) sulfinyl group, a sulfo group or a salt thereof, a sulfamoyl group, an acylsulfamoyl group, Examples thereof include a sulfonylsulfamoyl group or a salt thereof, a phosphoryl group, a group having a phosphoric amide or a phosphoric ester structure, a silyl group, and a stanyl group. These substituents may be further substituted with these substituents.

The electron-withdrawing group represented by Z in the formula (1) is a substituent whose Hammett's substituent constant σ _p can take a positive value. Carbonyl group, aryloxycarbonyl group, carbamoyl group, imino group, imino group substituted by N atom, thiocarbonyl group, sulfamoyl group, alkylsulfonyl group, arylsulfonyl group, nitro group, halogen atom,
A perfluoroalkyl group, a perfluoroalkaneamide group, a sulfonamide group, an acyl group, a formyl group, a phosphoryl group, a carboxy group (or a salt thereof), a sulfo group (or a salt thereof), a heterocyclic group, an alkenyl group, an alkynyl group, Examples include an acyloxy group, an acylthio group, a sulfonyloxy group, and an aryl group substituted with these electron-withdrawing groups. Here, the heterocyclic group is a saturated or unsaturated heterocyclic group, for example, a pyridyl group, a quinolyl group,
Examples thereof include a pyrazinyl group, a quinoxalinyl group, a benzotriazolyl group, an imidazolyl group, a benzimidazolyl group, a hydantoin-1-yl group, a succinimide group, and a phthalimide group. The electron-withdrawing group represented by Z in the formula (1) may further have a substituent, and as the substituent, R ¹¹ , R ¹² and R ^{13 in} the formula (1) represent The same substituents as the substituents which may be present at the time of expression are exemplified. In the formula (1), R ¹¹ and Z, R ¹² and R ¹³ , R
¹¹ and R ¹² , or R ¹³ and Z may be bonded to each other to form a cyclic structure. The cyclic structure formed at this time is a non-aromatic carbon ring or a non-aromatic hetero ring. It is.

Next, a preferred range of the compound represented by the formula (1) will be described. The silyl group represented by Z in the formula (1) is preferably a trimethylsilyl group, t
-Butyldimethylsilyl group, phenyldimethylsilyl group, triethylsilyl group, triisopropylsilyl group,
And a trimethylsilyldimethylsilyl group. The electron-withdrawing group represented by Z in the formula (1) is preferably a group having a total number of carbon atoms of 0 to 30, that is, a cyano group, an alkoxycarbonyl group, an aryloxycarbonyl group, a carbamoyl group, a thiocarbonyl group, Imino group, imino group substituted with N atom, sulfamoyl group, alkylsulfonyl group, arylsulfonyl group, nitro group, perfluoroalkyl group, acyl group, formyl group, phosphoryl group, acyloxy group, acylthio group, or any electron withdrawing A phenyl group substituted with a functional group, and more preferably,
Cyano group, alkoxycarbonyl group, carbamoyl group,
Imino group, sulfamoyl group, alkylsulfonyl group,
An arylsulfonyl group, an acyl group, a formyl group, a phosphoryl group, a trifluoromethyl group, or a phenyl group substituted with any electron-withdrawing group, and particularly preferably a cyano group, a formyl group, an acyl group, an alkoxycarbonyl group , An imino group or a carbamoyl group. The group represented by Z in the formula (1) is more preferably an electron-withdrawing group.

The substituent represented by R ¹¹ , R ¹² and R ¹³ in the formula (1) is preferably a group having a total carbon number of 0 to 30, specifically, Z in the above formula (1). A group having the same meaning as the electron-withdrawing group represented, and an alkyl group, a hydroxy group (or a salt thereof), a mercapto group (or a salt thereof), an alkoxy group, an aryloxy group, a heterocyclic oxy group, an alkylthio group, an arylthio group, Heterocyclic thio group, amino group,
Alkylamino group, arylamino group, heterocyclic amino group, ureido group, acylamino group, sulfonamide group,
Or a substituted or unsubstituted aryl group. Further, in the formula (1), R ¹¹ is preferably an electron-withdrawing group, an aryl group, an alkylthio group, an alkoxy group, or an acylamino group, a hydrogen atom, or a silyl group.

When R ¹¹ represents an electron-withdrawing group, preferably the following groups having a total of 0 to 30 carbon atoms, ie, a cyano group, a nitro group, an acyl group, a formyl group, an alkoxycarbonyl group,
An aryloxycarbonyl group, a thiocarbonyl group, an imino group, an imino group substituted with an N atom, an alkylsulfonyl group, an arylsulfonyl group, a carbamoyl group, a sulfamoyl group, a trifluoromethyl group, a phosphoryl group, a carboxy group (or a salt thereof), Or a saturated or unsaturated heterocyclic group, and a cyano group, an acyl group, a formyl group, an alkoxycarbonyl group, a carbamoyl group, an imino group, an imino group substituted with an N atom, a sulfamoyl group, a carboxy group (or a salt thereof) Or a saturated or unsaturated heterocyclic group. Particularly preferred are a cyano group, a formyl group, an acyl group, an alkoxycarbonyl group, a carbamoyl group, and a saturated or unsaturated heterocyclic group. When R ¹¹ represents an aryl group, it is preferably a substituted or unsubstituted phenyl group having 6 to 30 carbon atoms in total, and examples of the substituent include arbitrary substituents. Is preferred. In formula (1), R ¹¹ more preferably represents an electron-withdrawing group or an aryl group.

In the formula (1), the substituents represented by R ¹² and R ¹³ are preferably, specifically, Z
A group having the same meaning as the electron-withdrawing group represented by, an alkyl group, a hydroxy group (or a salt thereof), a mercapto group (or a salt thereof), an alkoxy group, an aryloxy group, a heterocyclic oxy group, an alkylthio group, an arylthio group, Examples include a heterocyclic thio group, an amino group, an alkylamino group, an anilino group, a heterocyclic amino group, an acylamino group, and a substituted or unsubstituted phenyl group. In the formula (1), R ¹² and R ¹³ are
More preferably, one of them is a hydrogen atom and the other represents a substituent. Preferably as the substituent,
Alkyl group, hydroxy group (or a salt thereof), mercapto group (or a salt thereof), alkoxy group, aryloxy group,
Heterocyclic oxy group, alkylthio group, arylthio group,
A heterocyclic thio group, an amino group, an alkylamino group, an anilino group, a heterocyclic amino group, an acylamino group (particularly a perfluoroalkaneamide group), a sulfonamide group, a substituted or unsubstituted phenyl group, or a heterocyclic group; More preferably a hydroxy group (or a salt thereof), a mercapto group (or a salt thereof), an alkoxy group, an aryloxy group, a heterocyclic oxy group, an alkylthio group, an arylthio group, a heterocyclic thio group, or a heterocyclic group, Particularly preferred are a hydroxy group (or a salt thereof), an alkoxy group, and a heterocyclic group. In formula (1), it is also preferable that Z and R ¹¹ , or R ¹² and R ¹³ form a cyclic structure. The cyclic structure formed in this case is a non-aromatic carbocyclic ring or a non-aromatic hetero ring, preferably a 5- to 7-membered cyclic structure having a total carbon number including a substituent of 1 to 40, more preferably 3 to 30.

[0074] Among the compounds represented by formula (1), more One of preferred, Z is a cyano group, a formyl group, an acyl group, an alkoxycarbonyl group, an imino group or a carbamoyl group,, R ¹¹ is Represents an electron-withdrawing group or an aryl group, and one of R ^{12 and} R ¹³ is a hydrogen atom, and the other is a hydroxy group (or a salt thereof) or a mercapto group
(Or a salt thereof), an alkoxy group, an aryloxy group, a heterocyclic oxy group, an alkylthio group, an arylthio group, a heterocyclic thio group, or a heterocyclic group.
Furthermore, one of the particularly preferable compounds represented by the formula (1) is that Z and R ^{11 form a} non-aromatic 5- to 7-membered cyclic structure, and R ¹² or R ¹³ Is a hydrogen atom, the other is a hydroxy group (or a salt thereof),
It is a compound that represents a mercapto group (or a salt thereof), an alkoxy group, an aryloxy group, a heterocyclic oxy group, an alkylthio group, an arylthio group, a heterocyclic thio group, or a heterocyclic group. At this time, Z which forms a non-aromatic cyclic structure together with R ¹¹ is preferably an acyl group, a carbamoyl group, an oxycarbonyl group, a thiocarbonyl group, a sulfonyl group, and the like. R ¹¹ is an acyl group, a carbamoyl group , An oxycarbonyl group, a thiocarbonyl group, a sulfonyl group, an imino group, an imino group substituted by an N atom, an acylamino group, and a carbonylthio group.

Next, the compound represented by the formula (2) will be described. In the formula (2), R ¹⁴ represents a substituent. Examples of the substituent represented by R ¹⁴ include the same as those described for the substituents of R ^{11 to} R ^{13 in} the formula (1). The substituent represented by R ¹⁴ is preferably an electron-withdrawing group or an aryl group. When R ¹⁴ represents an electron withdrawing group, preferably
The following groups having a total carbon number of 0 to 30, that is, a cyano group, a nitro group, an acyl group, a formyl group, an alkoxycarbonyl group,
Aryloxycarbonyl group, alkylsulfonyl group,
Arylsulfonyl group, carbamoyl group, sulfamoyl group, trifluoromethyl group, phosphoryl group, imino group, or a saturated or unsaturated heterocyclic group, further cyano group, acyl group, formyl group, alkoxycarbonyl group, carbamoyl group, Sulfamoyl, alkylsulfonyl, arylsulfonyl, and heterocyclic groups are preferred. Particularly preferred are a cyano group, a formyl group, an acyl group, an alkoxycarbonyl group, a carbamoyl group, and a heterocyclic group. When R ¹⁴ represents an aryl group, preferably a total carbon number of 0 to 30, a substituted or unsubstituted phenyl group, the substituent, R ^11, R ¹² of formula (1),
When R ¹³ represents a substituent, the same as those described as the substituent can be mentioned. R ¹⁴ is particularly preferably a cyano group, an alkoxycarbonyl group, a carbamoyl group, a heterocyclic group, or a substituted or unsubstituted phenyl group, and most preferably a cyano group, a heterocyclic group, or an alkoxycarbonyl group.

Next, the compound represented by the formula (3) will be described in detail. In the formula (3), X and Y each independently represent a hydrogen atom or a substituent, and A and B each independently represent
Represents an alkoxy group, an alkylthio group, an alkylamino group, an aryloxy group, an arylthio group, an anilino group, a heterocyclic thio group, a heterocyclic oxy group, or a heterocyclic amino group. X and Y or A and B may be bonded to each other to form a cyclic structure. As the substituents represented by X and Y in the formula (3), the same substituents as described for the substituents R ^{11 to} R ^{13 in} the formula (1) can be mentioned. Specifically, alkyl groups (including perfluoroalkyl groups, trichloromethyl groups, etc.), aryl groups, heterocyclic groups, halogen atoms, cyano groups, nitro groups, alkenyl groups, alkynyl groups, acyl groups, formyl groups, alkoxy groups Carbonyl group, aryloxycarbonyl group, imino group, imino group substituted with an N atom, carbamoyl group, thiocarbonyl group, acyloxy group, acylthio group, acylamino group,
Alkylsulfonyl, arylsulfonyl, sulfamoyl, phosphoryl, carboxy (or salt thereof), sulfo (or salt thereof), hydroxy (or salt thereof), mercapto (or salt thereof), alkoxy, aryl Oxy group, heterocyclic oxy group, alkylthio group, arylthio group, heterocyclic thio group, amino group,
Examples thereof include an alkylamino group, an anilino group, a heterocyclic amino group, and a silyl group. These groups may further have a substituent. X and Y may be bonded to each other to form a cyclic structure, and the cyclic structure formed in this case may be a non-aromatic carbon ring or a non-aromatic hetero ring. .

The substituent represented by X and Y in the formula (3) is preferably a group having 1 to 40 carbon atoms, more preferably 1 to 30 carbon atoms, and is preferably a cyano group, an alkoxycarbonyl group, Aryloxycarbonyl group, carbamoyl group, imino group, imino group substituted with N atom, thiocarbonyl group, sulfamoyl group, alkylsulfonyl group, arylsulfonyl group, nitro group, perfluoroalkyl group, acyl group, formyl group, phosphoryl group , An acylamino group, an acyloxy group, an acylthio group, a heterocyclic group, an alkylthio group, an alkoxy group, or an aryl group. In the formula (3), X and Y are more preferably cyano group, nitro group, alkoxycarbonyl group, carbamoyl group, acyl group, formyl group, acylthio group, acylamino group, thiocarbonyl group, sulfamoyl group, alkylsulfonyl group, aryl Sulfonyl group, imino group,
An imino group, a phosphoryl group, a trifluoromethyl group, a heterocyclic group, or a substituted phenyl group substituted with an N atom, particularly preferably a cyano group, an alkoxycarbonyl group, a carbamoyl group, an alkylsulfonyl group, an arylsulfonyl group , Acyl group, acylthio group, acylamino group, thiocarbonyl group, formyl group, imino group, N
Examples include an imino group substituted with an atom, a heterocyclic group, and a phenyl group substituted with an arbitrary electron-withdrawing group.

It is also preferable that X and Y combine with each other to form a non-aromatic carbon ring or a non-aromatic hetero ring. At this time, the formed cyclic structure is preferably a 5- to 7-membered ring, and has a total carbon number of 1 to 40, more preferably 3 to
30 is preferred. X and Y forming a cyclic structure include an acyl group, a carbamoyl group, an oxycarbonyl group,
Preferred are a thiocarbonyl group, a sulfonyl group, an imino group, an imino group substituted with an N atom, an acylamino group, a carbonylthio group and the like. In the formula (3), A and B each independently represent an alkoxy group, an alkylthio group, an alkylamino group, an aryloxy group, an arylthio group, an anilino group,
Represents a heterocyclic thio group, a heterocyclic oxy group, or a heterocyclic amino group, which may be bonded to each other to form a cyclic structure. The group represented by A or B in the formula (3) is preferably a group having a total carbon number of 1 to 40, more preferably a group having a total carbon number of 1 to 30, and may further have a substituent.

In formula (3), A and B more preferably combine with each other to form a cyclic structure.
The cyclic structure formed at this time is preferably a 5- to 7-membered non-aromatic hetero ring, and preferably has a total carbon number of 1 to 40, and more preferably 3 to 30. In this case, A, by way of example in which B is linked (-A-B-), for example _{-O- (CH 2) 2 -O -} , - O-
(CH ₂ ) ₃ -O-, -S- (CH ₂ ) ₂ -S-, -S- (CH ₂ ) ₃ -S-, -S-ph-S-,-
N (CH ₃ )-(CH ₂ ) ₂ -O-, -N (CH ₃ )-(CH ₂ ) ₂ -S-, -O- (CH ₂ ) ₂ -S
-, -O- (CH ₂ ) ₃ -S-, -N (CH ₃ ) -ph-O-, -N (CH ₃ ) -ph-S-, -N
(ph)-(CH ₂ ) ₂ -S- and the like.

The compounds represented by the formulas (1) to (3) used in the present invention may have incorporated therein an adsorptive group that adsorbs to silver halide. Examples of such an adsorbing group include U.S. Pat. Nos. 4,385,108 and 4,459,347 such as an alkylthio group, an arylthio group, a thiourea group, a thioamide group, a mercapto heterocyclic group and a triazole group.
And JP-A-59-195233 and JP-A-59-20023.
No. 1, No. 59-201045, No. 59-201046
Nos. 59-201047 and 59-201048
No. 59-201049, JP-A-61-17073.
Nos. 3, 61-270744, 62-948, 63-234244, 63-234245, and 6
Groups described in JP-A-3-234246. These adsorbing groups to silver halide may be precursors. Examples of such a precursor include the groups described in JP-A-2-285344. The compounds represented by the formulas (1) to (3) used in the present invention may have incorporated therein a ballast group or a polymer commonly used in immobile photographic additives such as couplers. Particularly, those incorporating a ballast group are one of preferred examples of the present invention. The ballast group has a carbon number of 8 or more and is relatively inert to photographic properties, such as an alkyl group, an aralkyl group, an alkoxy group,
It can be selected from a phenyl group, an alkylphenyl group, a phenoxy group, an alkylphenoxy group and the like. Examples of the polymer include those described in JP-A-1-100530.

The compounds represented by the formulas (1) to (3) used in the present invention contain a cationic group (specifically, a group containing a quaternary ammonium group, or a quaternized group). A nitrogen-containing heterocyclic group containing a nitrogen atom), a group containing a repeating unit of an ethyleneoxy group or a propyleneoxy group, an (alkyl, aryl, or heterocyclic) thio group, or a dissociable group (carboxy group) dissociable by a base , A sulfo group,
Acylsulfamoyl group, carbamoylsulfamoyl group, etc.). Particularly, a group containing a group containing a repeating unit of an ethyleneoxy group or a propyleneoxy group or a group containing an (alkyl, aryl, or heterocyclic) thio group is one of preferred examples of the present invention. Specific examples of these groups include, for example, JP-A-7-2
No. 34471, JP-A-5-333466, JP-A-6-633
19032, JP-A-6-19031, JP-A-5-4
No. 5761, U.S. Pat. No. 4,994,365, U.S. Pat.
88604, JP-A-3-259240, JP-A-7-
No. 5610, JP-A-7-244348, German Patent 40
06032 and the like. Then the formula
Specific examples of the compounds represented by (1) to (3) are shown below.
However, the present invention is not limited to the following compounds.

[0082]

Embedded image

[0083]

Embedded image

[0084]

Embedded image

[0085]

Embedded image

The compounds represented by the formulas (1) to (3) used in the present invention may be water or a suitable organic solvent such as alcohols (methanol, ethanol, propanol, fluorinated alcohol) and ketones (acetone, Methylethylketone), dimethylformamide, dimethylsulfoxide,
It can be used by dissolving it in methylcellosolve or the like.
Also, by an already well-known emulsification dispersion method, an oil such as dibutyl phthalate, tricresyl phosphate, glyceryl triacetate or diethyl phthalate, and an auxiliary solvent such as ethyl acetate or cyclohexanone are dissolved and mechanically emulsified and dispersed. An object can be prepared and used. Alternatively, a compound powder can be dispersed in a suitable solvent such as water by a ball mill, a colloid mill, or ultrasonic waves by a method known as a solid dispersion method and used. Formulas (1) to (3) used in the present invention
May be added to the layer on the image forming layer side with respect to the support, that is, the image forming layer or any other layer, but is preferably added to the image forming layer or a layer adjacent thereto. .

The addition amount of the compounds represented by the formulas (1) to (3) used in the present invention is preferably 1 × 10 ^-6 to 1 mol per 1 mol of silver, and 1 × 10 ^{-5 to} 5 ×. 10 ^-1 mol is more preferable, and 2 x 10 ^-5 to 2 x 10 ^-1 mol is most preferable. formula
The compounds represented by formulas (1) to (3) can be easily synthesized by a known method. For example, US Pat.
No. 515, US Pat. No. 5,635,339, US Pat.
No. 4130, International Patent WO-97 / 34196, or Japanese Patent Application Nos. 9-309813 and 9-272002.
The compound can be synthesized with reference to the method described in (1). The compounds represented by the formulas (1) to (3) used in the present invention may be used alone or in combination of two or more. In addition to the above, US Pat. No. 5,545,515 and US Pat.
No. 339, US Pat. No. 5,654,130, International Publication WO9
No. 7/34196, the compounds described in U.S. Pat. No. 5,686,228, or alternatively, Japanese Patent Application Nos. 9-228881, 9-273935, 9-309813, 9-296174, and 9-296174. No. 9-282564, Japanese Patent Application No. 9-272002, Japanese Patent Application No. 9-272003,
Compounds described in Japanese Patent Application No. 9-332388 may be used in combination.

In the present invention, a hydrazine derivative may be used in combination as a nucleating agent. In that case, the following hydrazine derivatives are preferably used. The hydrazine derivative used in the present invention can also be synthesized by various methods described in the following patents. Compounds represented by (Chemical Formula 1) described in JP-B-6-77138, specifically, compounds described on pages 3 and 4 of the same publication. A compound represented by the general formula (I) described in JP-B-6-93082.
Compounds 1-38 on pages 18-18. Compounds represented by the general formulas (4), (5) and (6) described in JP-A-6-230497, specifically the compound 4- described on pages 25 and 26 of the same publication. 1 to compound 4-10, compound 5 described on pages 28 to 36
-1 to 5-42, and compounds 6-1 to 6-7 described on pages 39 and 40. Compounds represented by general formulas (1) and (2) described in JP-A-6-289520, specifically, from page 5 to
Compounds 1-1) to 1-17) and 2-1) described on page 7. JP Hei 6
Compounds represented by (Chemical Formula 2) and (Chemical Formula 3) described in JP-A-313936, specifically, compounds described on pages 6 to 19 of the same publication.
Compounds represented by (Chemical Formula 1) described in JP-A-6-313951, specifically, compounds described on pages 3 to 5 of the same. JP
Compounds represented by formula (I) described in No. 7-5610, specifically, compounds I-1 to I-38 described on pages 5 to 10 of the same publication.
A compound represented by the general formula (II) described in JP-A-7-77783, specifically, a compound II-1 described on pages 10 to 27 of the publication;
~ II-102. Compounds represented by formulas (H) and (Ha) described in JP-A-7-104426, specifically, compounds H-1 to H-44 described on pages 8 to 15 of the same publication. JP 9-2208
No. 2 is a compound characterized by having an anionic group or a nonionic group forming an intramolecular hydrogen bond with a hydrogen atom of hydrazine in the vicinity of the hydrazine group. B), compounds represented by the general formulas (C), (D), (E) and (F), specifically the compounds N-1 to N-30 described in the publication . A compound represented by the general formula (1) described in JP-A-9-22082,
Specifically, compounds D-1 to D-55 described in the publication.

Further, “Known Techniques (1 to
207) ”(published by Aztec) on pages 25 to 34. Compounds D-2 and D-39 of JP-A-62-86354 (pages 6 to 7). The hydrazine derivative used in the present invention may be a suitable organic solvent such as alcohols (methanol, ethanol, propanol, fluorinated alcohol), ketones (acetone, methyl ethyl ketone),
It can be used by dissolving in dimethylformamide, dimethylsulfoxide, methylcellosolve and the like. Also,
By an already well-known emulsification dispersion method, an oil such as dibutyl phthalate, tricresyl phosphate, glyceryl triacetate or diethyl phthalate is dissolved using an auxiliary solvent such as ethyl acetate or cyclohexanone, and the emulsified dispersion is mechanically dispersed. It can be manufactured and used. Alternatively, a powder of a hydrazine derivative can be dispersed in water by a ball mill, a colloid mill, or an ultrasonic wave by a method known as a solid dispersion method and used.

The hydrazine derivative used in the present invention is
The image forming layer on the image forming layer side with respect to the support or other
May be added to any of the binder layers of
To be added to the layer or the binder layer adjacent to it.
Is preferred. Of the hydrazine derivative used in the present invention
The addition amount was 1 × 10^-6~ 1 × 10^-2Prefer mol
1 × 10^-Five~ 5 × 10^-3Mole is more preferred, 2 × 10^-Five
~ 5 × 10 ^-3Molar is most preferred. Also, the present invention is
For image formation, a contrast enhancement agent together with the nucleating agent described above.
Can be used in combination. For example, U.S. Pat.
No. 5 amine compounds, specifically AM-1 to AM-
5, the hydroxamic acids described in 5,545,507, specifically,
Acrylonitrile described in HA-1 to HA-11 and 5,545,507
And specifically described in CN-1 to CN-13 and 5,558,983.
Hydrazine compounds, specifically CA-1 to CA-6, JP
Onium salts described in JP-A-9-297368, specifically
Uses A-1 to A-42, B-1 to B-27, C-1 to C-14, etc.
Can be The method of synthesizing these high contrast enhancement agents,
The addition method, the addition amount, etc. are described in each of the cited patents.
Can be done as is.

In the present invention, an acid or a salt thereof formed by hydration of diphosphorus pentoxide is preferably used in combination with a nucleating agent. Acids or salts thereof formed by hydration of diphosphorus pentoxide include metaphosphoric acid (salt), pyrophosphoric acid (salt), orthophosphoric acid (salt), triphosphoric acid (salt), tetraphosphoric acid (salt), hexametaline Acids (salts); Particularly preferred acids or salts thereof formed by hydration of diphosphorus pentoxide include orthophosphoric acid (salt) and hexametaphosphoric acid (salt),
Specific salts include sodium orthophosphate, sodium dihydrogen orthophosphate, sodium hexametaphosphate,
Examples include ammonium hexametaphosphate. The acid or salt thereof formed by hydration of diphosphorus pentoxide, which can be preferably used in the present invention, is added to the image forming layer or the binder layer adjacent thereto in that the desired effect is exhibited in a small amount. The amount of the acid or salt thereof formed by hydration of diphosphorus pentoxide used in the present invention (the coating amount per 1 m ^{2 of the} light-sensitive material) may be a desired amount in accordance with the performance such as sensitivity and fog. ~ 500 mg / m ² is preferred, and 0.5
-100 mg / m ² is more preferred.

The photothermographic material of the present invention preferably contains a reducing agent for an organic silver salt. The reducing agent for the organic silver salt may be any substance that reduces silver ions to metallic silver, preferably an organic substance. Conventional photographic developers such as phenidone, hydroquinone and catechol are useful, but hindered phenol reducing agents are preferred. The reducing agent is preferably contained in an amount of 5 to 50 mol%, more preferably 10 to 40 mol%, per 1 mol of silver on the surface having the image forming layer. The layer to which the reducing agent is added may be any layer on the side having the image forming layer. When it is added to a layer other than the image forming layer, it is preferable to use a relatively large amount of 10 to 50 mol% with respect to 1 mol of silver. Further, the reducing agent may be a so-called precursor which is derivatized so as to have a function effectively only during development.

In photothermographic materials utilizing organic silver salts, a wide range of reducing agents are disclosed in JP-A-46-6074 and JP-A-47-1238.
47-33621, 49-46427, 49-115540, 50-14
No. 334, No. 50-36110, No. 50-147711, No. 51-32632,
No. 51-1023721, No. 51-32324, No. 51-51933, No. 52-8
4727, 55-108654, 56-146133, 57-82828
No. 57-82829, JP-A-6-3793, U.S. Pat.
No. 6, 3,751,252, 3,751,255, 3,761,270,
3,782,949, 3,839,048, 3,928,686, 5,4
No. 64,738, German Patent 2321328, European Patent 692732 and the like. For example, phenylamide oxime,
Amide oximes such as 2-thienylamide oxime and p-phenoxyphenylamide oxime; azines such as 4-hydroxy-3,5-dimethoxybenzaldehyde azine; 2,2′-bis (hydroxymethyl) propionyl-β-
A combination of an aliphatic carboxylic acid aryl hydrazide such as a combination of phenylhydrazine and ascorbic acid with ascorbic acid; a combination of polyhydroxybenzene with hydroxylamine, reductone and / or hydrazine (eg, hydroquinone and bis (ethoxyethyl) hydroxyl Amines, piperidinohexose reductone or a combination of formyl-4-methylphenylhydrazine); hydroxamic acids such as phenylhydroxamic acid, p-hydroxyphenylhydroxamic acid and β-alinine hydroxamic acid; azine and sulfonamide phenol (E.g., phenothiazine and 2,6-dichloro-4-
Benzenesulfonamidophenol); ethyl-α-
Α-cyanophenylacetic acid derivatives such as cyano-2-methylphenylacetate and ethyl-α-cyanophenylacetate; 2,2′-dihydroxy-1,1′-binaphthyl, 6,6′-dibromo-2,2′- Dihydroxy-1,1'-binaphthyl and bis (2
Bis-β-naphthol as exemplified by -hydroxy-1-naphthyl) methane; bis-β-naphthol and 1,3-dihydroxybenzene derivatives (eg, 2,4-dihydroxybenzophenone or 2 ′, 4′-dihydroxy Acetophenone); 5-pyrazolone, such as 3-methyl-1-phenyl-5-pyrazolone; dimethylaminohexose reductone, anhydrodihydroaminohexose reductone and anhydrodihydropiperidone hexose reductone. Reductones as exemplified; sulfonamide phenol reducing agents such as 2,6-dichloro-4-benzenesulfonamidophenol and p-benzenesulfonamidophenol; 2-phenylindane-1,3-dione and the like; 2,2- Chromanes such as dimethyl-7-t-butyl-6-hydroxychroman; 2,6-dimethoxy-3,5-dicarboethoxy-1,4-dihydrogen 1,4-dihydropyridines such as lopyridine; bisphenols (eg, bis (2-hydroxy-3-t-butyl-5-methylphenyl) methane, 2,2-bis (4-hydroxy-3-methylphenyl) propane, 4 , 4-Ethylidene-bis (2-t-butyl-6-methylphenol), 1,1, -bis (2-hydroxy-3,5-dimethylphenyl) -3,5,5-trimethylhexane and 2,2 -Bis (3,5-dimethyl-4-hydroxyphenyl) propane, etc.); ascorbic acid derivatives (eg, 1-ascorbyl palmitate, ascorbyl stearate, etc.); and aldehydes and ketones such as benzyl and biacetyl; 3-pyrazolidone and Certain indane-1,3-diones; chromanol (such as tocopherol).
Particularly preferred reducing agents are bisphenol and chromanol.

The reducing agent used in the present invention may be added by any method such as a solution, a powder, and a solid fine particle dispersion. The dispersion of the solid fine particles is carried out by a known means for making fine (for example, a ball mill, a vibration ball mill, a sand mill, a colloid mill, a jet mill, a roller mill, etc.). When dispersing the solid fine particles, a dispersing aid may be used.

When an additive known as a "toning agent" for improving an image is contained, the optical density may be increased. The toning agent may also be advantageous in forming a black silver image. The toning agent is preferably contained in an amount of 0.1 to 50% mol per mol of silver on the surface having the image forming layer,
More preferably, it is contained in an amount of 0.5 to 20% by mole. Further, the toning agent may be a so-called precursor which is derivatized so as to have a function effectively only during development. For photothermographic materials using organic silver salts, a wide range of color
46-6077, 47-10282, 49-5019, 49-5020
Nos. 49-91215, 49-91215, 50-2524, 50-
32927, 50-67132, 50-67641, 50-114217
No. 51-3223, No. 51-27923, No. 52-14788, No. 52-
99813, 53-1020, 53-76020, 54-156524
No. 54-156525, No. 61-183642, JP-A-4-56848
No., JP-B-49-10727, JP-B-54-20333, U.S. Pat.
No. 254, No. 3,446,648, No. 3,782,941, No. 4,123,282
No. 4,510,236, British Patent 1380795, Belgian Patent
No. 841910. Examples of toning agents are phthalimide and N-hydroxyphthalimide; succinimide, pyrazolin-5-one, and quinazolinone, 3-phenyl-2-pyrazolin-5-one, 1-phenylurazole,
Cyclic imides such as quinazoline and 2,4-thiazolidinedione; naphthalimide (eg, N-hydroxy-1,8-naphthalimide); cobalt complex (eg, cobalt hexamine trifluoroacetate); 3-mercapto-1,2 Mercaptans exemplified by 2,4-triazole, 2,4-dimercaptopyrimidine, 3-mercapto-4,5-diphenyl-1,2,4-triazole and 2,5-dimercapto-1,3,4-thiadiazole; N- (aminomethyl) aryldicarboximide,
(E.g., (N, N-dimethylaminomethyl) phthalimide and N, N- (dimethylaminomethyl) -naphthalene-2,3-dicarboximide); and blocked pyrazoles, isothiuronium derivatives and certain photobleaching agents ( For example, N, N'-hexamethylenebis (1-carbamoyl-3,5-dimethylpyrazole), 1,8- (3,6-diazaoctane) bis (isothiuronium trifluoroacetate) and 2-tribromomethylsulfonyl )-(Benzothiazole)); and 3-ethyl-5 [(3-ethyl-2-benzothiazolinylidene)
-1-methylethylidene] -2-thio-2,4-oxazolidinedione; phthalazinone, phthalazinone derivative or metal salt, or 4- (1-naphthyl) phthalazinone, 6-chlorophthalazinone, 5,7-dimethoxyphthalazinone And derivatives such as 2,3-dihydro-1,4-phthalazinedione; combinations of phthalazinone with phthalic acid derivatives such as phthalic acid, 4-methylphthalic acid, 4-nitrophthalic acid and tetrachlorophthalic anhydride; Phthalazine, phthalazine derivatives (e.g., 4- (1-naphthyl) phthalazine, 6-chlorophthalazine, 5,7-dimethoxyphthalazine, 6-iso-butylphthalazine, 6-tert-butylphthalazine, 5,7- Dimethylphthalazine, and derivatives such as 2,3-dihydrophthalazine) or metal salts; phthalazine and its derivatives and phthalic acid derivatives (eg, phthalic acid, 4-methylphthalic acid, 4-nitrate) Quinazolinedione, benzoxazine or naphthoxazine derivatives; rhodium that functions not only as a tone control agent but also as a source of halide ions for silver halide formation in situ Complexes, such as ammonium hexachlororhodate (III), rhodium bromide, rhodium nitrate and potassium hexachlororhodate (III);
Inorganic peroxides and persulfates, for example, ammonium disulfide and hydrogen peroxide; 1,3-benzoxazine-
Benzoxazine-2,4-diones such as 2,4-dione, 8-methyl-1,3-benzoxazine-2,4-dione and 6-nitro-1,3-benzoxazine-2,4-dione; Pyrimidine and asymmetric-triazines (e.g., 2,4-dihydroxypyrimidine, 2-hydroxy-4-aminopyrimidine, etc.), azauracil, and tetraazapentalene derivatives (e.g., 3,6
-Dimercapto-1,4-diphenyl-1H, 4H-2,3a, 5,6a-tetraazapentalene and 1,4-di (o-chlorophenyl)-
3,6-dimercapto-1H, 4H-2,3a, 5,6a-tetraazapentalene).

The toning agent used in the present invention may be added by any method such as a solution, a powder, and a solid fine particle dispersion. The dispersion of the solid fine particles is carried out by a known means for making fine (for example, a ball mill, a vibration ball mill, a sand mill, a colloid mill, a jet mill, a roller mill, etc.). When dispersing the solid fine particles, a dispersing aid may be used. The surface pH of the photothermographic material of the present invention before the heat development is preferably 6 or less from the viewpoint of reducing fogging during storage, particularly 5.5 or less, more preferably 5.3 or less. The lower limit is not particularly limited, but is about 3. Membrane pH
It is preferable to use an organic acid such as a phthalic acid derivative, a nonvolatile acid such as sulfuric acid, or a volatile base such as ammonia from the viewpoint of reducing the film surface pH. In particular, ammonia is preferable for achieving a low film surface pH since ammonia is easily volatilized and can be removed before the application step and the heat development. When measuring the film surface pH of the photothermographic material of the present invention, the photothermographic material 2.
5 cm × 2.5 cm is folded into a boat shape, 300 μl of distilled water is dropped on the image forming layer side, and the solution is left standing for 30 minutes. It is preferable to measure for 1 minute with a pH meter.

As the binder used in the present invention, a polymer latex described below is preferably used. At least one of the image forming layers containing the photosensitive silver halide of the photothermographic material of the present invention is preferably an image forming layer using the polymer latex described below as 50% by weight or more of the total binder. (Hereinafter, this image forming layer is referred to as “image forming layer in the present invention”, and the polymer latex used as a binder is referred to as “polymer latex used in the present invention.”) The polymer latex is not limited to the image forming layer, but may be a protective layer or a backing layer. When the photothermographic material of the present invention is used for printing in which dimensional change is a problem, it is preferable to use a polymer latex for the protective layer and the back layer. However, the "polymer latex" referred to here is a water-insoluble hydrophobic polymer dispersed as fine particles in a water-soluble dispersion medium. The dispersion state is such that the polymer is emulsified in a dispersion medium, emulsion-polymerized, micelle-dispersed, or partially dispersed in polymer molecules and molecular chains themselves are molecularly dispersed. Any of them may be used. The polymer latex used in the present invention is described in "Synthetic Resin Emulsion" (edited by Tadashi Okuda and Hiroshi Inagaki, published by the Society of Polymer Publishing (1978)), "Application of Synthetic Latex (edited by Takaaki Sugimura, Yasuo Kataoka, Soichi Suzuki, Keiji Kasahara) , Published by Kobunshi Kankokai (1993)), "Synthesis of Synthetic Latex (Souichi Muroi, published by Kobunshi Kankokai (1970))" and the like. The average particle size of the dispersed particles is 1 to 50,000 nm, more preferably
A range of about 5 to 1000 nm is preferable. There is no particular limitation on the particle size distribution of the dispersed particles, and those having a wide particle size distribution or those having a monodispersed particle size distribution may be used.

The polymer latex used in the present invention may be a so-called core / shell type latex other than a polymer latex having a normal uniform structure. In this case, it may be preferable to change the glass transition temperature of the core and the shell. The glass transition temperature (Tg) of the polymer latex preferably used as a binder in the present invention is as follows:
The preferred range differs between the back layer and the image forming layer. In the image forming layer, the temperature is preferably -30 to 40 ° C. in order to promote diffusion of the photographically useful material during thermal development. When used as a protective layer or back layer, contact with various devices is required.
Glass transition temperatures of 70 ° C. are preferred. The minimum film forming temperature (MFT) of the polymer latex used in the present invention is -30 ° C to 90 ° C,
More preferably, about 0 ° C to 70 ° C. A film-forming auxiliary may be added to control the minimum film-forming temperature. An organic compound (usually an organic solvent) that lowers the minimum film forming temperature of the polymer latex, also called a plasticizer
For example, it is described in the aforementioned "Synthesis of Synthetic Latex (Souichi Muroi, published by Kobunshi Kankokai (1970))".

The polymer used in the polymer latex used in the present invention includes acrylic resin, vinyl acetate resin, polyester resin, polyurethane resin, rubber resin, vinyl chloride resin, vinylidene chloride resin, polyolefin resin, or a copolymer thereof. and so on. 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 preferably from 5000 to 100000, more preferably from about 10,000 to 100,000 in number average molecular weight. If the molecular weight is too small, the mechanical strength of the image forming layer is insufficient, and if it is too large, the film-forming properties are poor, which is not preferable.

Specific examples of the polymer latex used as a binder for the image forming layer in the photothermographic material of the present invention include the following. Latex of methyl methacrylate / ethyl acrylate / methacrylic acid copolymer, methyl methacrylate / butadiene /
Latex of itaconic acid copolymer, latex of ethyl acrylate / methacrylic acid copolymer, latex of methyl methacrylate / 2-ethylhexyl acrylate / styrene / acrylic acid copolymer, styrene /
Butadiene / acrylic acid copolymer latex, styrene / butadiene / divinylbenzene / methacrylic acid copolymer latex, methyl methacrylate / vinyl chloride / acrylic acid copolymer latex, vinylidene chloride / ethyl acrylate / acrylonitrile / methacrylic acid copolymer latex. More specifically, methyl methacrylate / ethyl acrylate / methacrylic acid = 33.5 wt% / 50 wt% / 16.5 wt
% Copolymer latex, methyl methacrylate / butadiene / itaconic acid = 47.5 wt% / 47.5 wt%
% / 5 wt% copolymer latex, ethyl acrylate / methacrylic acid = 95 wt% / 5 wt% copolymer latex, and the like. Such polymers are also commercially available, and the following polymers can be used. For example, as an example of acrylic resin, Sebian A-46
35,46583, 4601 (manufactured by Daicel Chemical Industries, Ltd.), Nipo
l Lx811, 814, 821, 820, 857 (Zeon Corporation)
Polyester resins such as VONCORT-R3340, R3360, R3370, 4280 (all manufactured by Dainippon Ink and Chemicals, Inc.), and FINETEX ES650, 611, 675, 850 (all manufactured by Dainippon Ink and Chemicals) HYDRAN AP10, 2 as polyurethane resin such as WD-size, WMS (all manufactured by Eastman Chemical)
LACSTAR 7310K, 3307B, 4700H, 7132C as rubber-based resins such as 0, 30, 40 (all manufactured by Dainippon Ink and Chemicals, Inc.)
(Dai Nippon Ink Chemical Co., Ltd.), Nipol Lx410, 43
G351 and G576 (both manufactured by Zeon Corporation) such as 0, 435, 438C, (all manufactured by Zeon Corporation)
Examples of vinylidene chloride resins include L502 and L513 (all manufactured by Asahi Kasei Kogyo Co., Ltd.), Aron D7020, D504, and D5071 (all manufactured by Mitsui Toatsu Co., Ltd.). Chemical Co., Ltd.). These polymers may be used alone or as a blend of two or more as necessary.

In the image forming layer in the present invention, the above polymer latex is preferably used as 50% by weight or more of the whole binder, and more preferably 70% by weight or more of the above polymer latex. In the image forming layer in the present invention, if necessary, 50% by weight of all binders
%, A hydrophilic polymer such as gelatin, polyvinyl alcohol, methylcellulose, hydroxypropylcellulose, carboxymethylcellulose and hydroxypropylmethylcellulose may be added. The amount of the hydrophilic polymer to be added is preferably 30% by weight or less, more preferably 5% by weight or less of the total binder in the image forming layer.

The image forming layer in the present invention is preferably prepared by applying an aqueous coating solution and then drying it. However, the `` water-based '' here is 60% by weight of the solvent (dispersion medium) of the coating liquid.
It means that the above is water. As components other than water of the coating solution, water-miscible organic solvents such as methyl alcohol, ethyl alcohol, isopropyl alcohol, methyl cellosolve, ethyl cellosolve, dimethylformamide, and ethyl acetate can be used. Specific examples of the solvent composition include the following. Water / methanol = 90/10, water / methanol = 70/30, water / ethanol = 90/10, water / isopropanol = 90/10, water / dimethylformamide = 95
/ 5, water / methanol / dimethylformamide = 80/15 /
5, water / methanol / dimethylformamide = 90/5/5.
(However, the numbers represent% by weight.) The total amount of the binder in the image forming layer in the invention is 0.2 to 30 g.
/ M ² , more preferably in the range of 1 to 15 g / m ² . A crosslinking agent for crosslinking, a surfactant for improving coating properties, and the like may be added to the image forming layer in the invention.

The silver halide emulsion according to the present invention or /
And organic silver salts can be further protected against the formation of additional fog by antifoggants, stabilizers and stabilizer precursors, and stabilized against reduced sensitivity during storage in inventory. Suitable antifoggants, stabilizers and stabilizer precursors that can be used alone or in combination are the thiazonium salts described in U.S. Pat.Nos. 2,131,038 and 2,694,716, U.S. Pat. Azaindene, U.S. Pat.
8,663 mercury salt, U.S. Pat.No. 3,287,135 urazole, U.S. Pat.
Nitrone, nitroindazole, U.S. Patent No. 2,839,405
No. 3,220,839, thiuronium salts, and U.S. Pat.Nos. 2,566,263 and 2,597,915, palladium, platinum and gold salts, U.S. Pat.Nos. 4,108,665 and 4,442,202 No. 4,128,557
Nos. 4,137,079 and 4,138,365 and 4,
No. 4,59,350 and U.S. Pat.
And the phosphorus compounds described in 1,985.

Antifoggants preferably used in the present invention
Is an organic halide, for example, JP-A-50-119624
No., No. 50-120328, No. 51-121332, No. 54-58022, No.
56-70543, 56-99335, 59-90842, 61-12964
No. 2, 62-129845, JP-A-6-208191, 7-5621,
No. 7-2781, No. 8-15809, U.S. Pat.No. 5,340,712, No.
Nos. 5,369,000 and 5,464,737
Compounds. The antifoggant used in the present invention is a solvent.
Liquid, powder, solid fine particle dispersion, etc.
You may. Dispersion of solid fine particles can be performed by a known finer means (e.g.,
For example, ball mill, vibrating ball mill, sand mill, colloid
Do mill, jet mill, roller mill, etc.)
You. Also, when using a dispersion aid when dispersing solid fine particles,
Good. Although not required to practice the present invention, the emulsion layer
Mercury (II) salt as an antifoggant
Sometimes. A preferred mercury (II) salt for this purpose is aqueous acetic acid
Silver and mercury bromide. Addition of mercury used in the present invention
The amount is preferably 1 × 10 per mole of silver applied.
^-9Mol ~ 1 x 10^-3Mole, more preferably 1 × 10 ^-8Mol ~
1 × 10^-FourRange of moles.

The photothermographic material of the present invention may contain benzoic acids for the purpose of increasing the sensitivity and preventing fog. The benzoic acids may be any benzoic acid derivative, but examples of preferred structures include, for example, U.S. Pat.
No. 9-329864 and JP-A-9-329864.
And compounds described in JP-A No. 9-281637. The benzoic acid may be added to any part of the photosensitive material, but it is preferably added to the layer having the photosensitive layer, more preferably to the organic silver salt-containing layer. The benzoic acid may be added at any time during the preparation of the coating solution, and when added to the organic silver salt-containing layer, may be added at any time from the preparation of the organic silver salt to the coating solution, but after the preparation of the organic silver salt. To just before application. The benzoic acid may be added by any method such as powder, solution, and fine particle dispersion. Further, it may be added as a solution mixed with other additives such as a sensitizing dye, a reducing agent and a color tone agent. The benzoic acid may be added in any amount, but preferably 1 × 10 ⁻⁶ mol or more and 2 mol or less, more preferably 1 × 10 ⁻³ mol or more and 0.5 mol or less, per 1 mol of silver.

In the photothermographic material of the present invention, mercapto compounds, disulfide compounds, A thione compound can be contained. When a mercapto compound is used in the present invention, it may have any structure, but is preferably a compound represented by Ar-SM or Ar-SS-Ar. Wherein M is a hydrogen atom or an alkali metal atom, and Ar is an aromatic or fused aromatic ring having one or more nitrogen, sulfur, oxygen, selenium or tellurium atoms. Preferably, the heteroaromatic ring is benzimidazole, naphthimidazole, benzothiazole, naphthothiazole, benzoxazole, naphthoxazole, benzoselenazole, benzotellurazole, imidazole, oxazole, pyrazole, triazole, thiadiazole, tetrazole, triazine, pyrimidine, pyridazine , Pyrazine, pyridine, purine, quinoline or quinazolinone. The heteroaromatic ring includes, for example, halogens (e.g., Br and Cl), hydroxy, amino, carboxy,
Alkyl (e.g. one or more carbon atoms, preferably 1-4
Having one carbon atom), alkoxy (eg, having one or more carbon atoms, preferably 1-4 carbon atoms) and aryl (optionally having substituents)
And a substituent selected from the group consisting of:
As mercapto-substituted heteroaromatic compounds, 2-mercaptobenzimidazole, 2-mercaptobenzoxazole, 2-mercaptobenzothiazole, 2-mercapto-5
-Methylbenzimidazole, 6-ethoxy-2-mercaptobenzothiazole, 2,2'-dithiobis- (benzothiazole, 3-mercapto-1,2,4-triazole, 4,5-diphenyl-2-imidazolethiol, 2 -Mercaptoimidazole, 1-ethyl-2-mercaptobenzimidazole, 2-mercaptoquinoline, 8-mercaptopurine, 2-mercapto
-4 (3H) -quinazolinone, 7-trifluoromethyl-4-quinolinethiol, 2,3,5,6-tetrachloro-4-pyridinethiol, 4-amino-6-hydroxy-2-mercaptopyrimidine monohydrate , 2-amino-5-mercapto-1,3,4-thiadiazole, 3-amino-5-mercapto-1,2,4-triazole,
4-Hydrocyr-2-mercaptopyrimidine, 2-mercaptopyrimidine, 4,6-diamino-2-mercaptopyrimidine, 2
-Mercapto-4-methylpyrimidine hydrochloride, 3-mercapto-5-phenyl-1,2,4-triazole, 1-phenyl
-5-mercaptotetrazole, 3- (5-mercaptotetrazole) -sodium benzenesulfonate, N-methyl-N'-
Examples include [3- (5-mercaptotetrazolyl) phenyl] urea, 2-mercapto-4-phenyloxazole, and the like, but the present invention is not limited thereto. The addition amount of these mercapto compounds is 0.00 per mole of silver in the emulsion layer.
The range is preferably from 001 to 1.0 mole, more preferably from 0.001 to 0.3 mole per mole of silver.

In the image forming layer (photosensitive layer) in the present invention, a polyhydric alcohol (for example, glycerin and diol of the kind described in US Pat. No. 2,960,404) as a plasticizer and a lubricant, and US Pat. No. 2,588,765 are used. And fatty acids or esters described in US Pat. No. 3,121,060, and silicone resins described in UK Patent No. 955,061 can be used.

In the present invention, it is preferable to provide a protective layer on the image forming layer. As a binder for the protective layer, a polymer latex having a glass transition temperature of 25 ° C. or more and 70 ° C. or less is used as described above. Is preferred. In this case, at least 50% by weight of the total binder of the protective layer, preferably
It is preferable to use the above-mentioned polymer latex at 70% by weight or more. In the present invention, it is preferable to provide at least one such protective layer. The binder configuration and coating method of such a protective layer are the same as those of the image forming layer. As the polymer latex for the protective layer, acrylic, styrene, acryl / styrene, vinyl chloride, and vinylidene chloride polymer latexes are preferably used. Specifically, acrylic resin-based VONCORT R337
0, 4280, Nipol Lx857, methyl acrylate / 2-ethylhexyl (meth) acrylate / hydroxyethyl (meth) acrylate / styrene / (meth) acrylic acid copolymer, Nipol G576 vinyl chloride resin, Alon D5071 vinylidene chloride resin are preferably used. Can be The total amount of the binder for the protective layer used in the present invention is 0.2 to 5.0 g /
m ² , more preferably in the range of 0.5 to 4.0 g / m ² .

As the surface protective layer in the present invention, any anti-adhesion material may be used. Examples of anti-adhesion materials include wax, silica particles, styrene-containing elastomeric block copolymers (e.g., styrene-butadiene-styrene, styrene-isoprene-styrene), cellulose acetate, cellulose acetate butyrate, cellulose propionate and the like. And mixtures. Further, a crosslinking agent for crosslinking and a surfactant for improving coating properties may be added to the surface protective layer. In the image forming layer or the protective layer of the image forming layer in the present invention, a light absorbing material and a filter dye as described in U.S. Pat. It can be used in photographic elements, including: Also, for example, U.S. Patent No. 3,282,699
The dye can be mordanted as described in the item. As the amount of the filter dye used, the absorbance at the exposure wavelength is 0.1 to 3
Is preferred, and 0.2 to 1.5 is particularly preferred.

Various dyes and pigments can be used in the image forming layer (photosensitive layer) in the present invention from the viewpoint of improving color tone and preventing irradiation. Dyes and pigments used in the photosensitive layer may be any, for example, pigments and dyes described in the Color Index, specifically, pyrazoloazole dye, anthraquinone dye, azo dye, azomethine dye, oxonol dye, carbocyanine dye , Styryl dyes, triphenylmethane dyes, indoaniline dyes, indophenol dyes, organic pigments such as phthalocyanine, and inorganic pigments. Preferred dyes used in the present invention are anthraquinone dyes
(For example, compounds 1 to 9 described in JP-A-5-341441, JP-A-5-15-1
65147 described compounds 3-6-18 and 3-23-38, etc.), azomethine dyes (compounds 17-47 described in JP-A-5-341441), indoaniline dyes (e.g. described in JP-A-5-289227) Compounds 11 to 19, compound 47 described in JP-A-5-341441, compounds 2-10 to 11 described in JP-A-5-165147) and azo dyes (compounds 10 to 16 described in JP-A-5-341441) are included. No. As a method for adding these dyes, any method such as a solution, an emulsion, a solid fine particle dispersion, and a state in which the dye is mordanted with a polymer mordant may be used. The amount of these compounds is determined by absorption of the purpose, generally 1 m ² per 1 × 10
It is preferable to use in the range of ^-6 g to 1 g.

The photothermographic material of the present invention has at least one light-sensitive layer (image forming layer) containing a silver halide emulsion on one side of a support, and has a back layer on the other side. It is preferably a so-called single-sided photosensitive material. In the present invention, the back layer has a maximum absorption of about 0.
It is preferably from 3 to 2.0. Desired range is 750
When it is from 1 to 1400 nm, the optical density at 750 to 360 nm is preferably from 0.005 to less than 0.5, more preferably an antihalation layer having an optical density from 0.001 to less than 0.3. Desired range is 750nm
If not more than the maximum absorption of the desired range before image formation is 0.3 or more and 2.0 or less, and further after 360-750 after image formation.
It is preferable that the antihalation layer has an optical density of 0.005 or more and less than 0.3. There is no particular limitation on the method of reducing the optical density after image formation to the above range, for example, a method of reducing the density by dyeing by heating to reduce the density by heating as described in Belgian Patent No. 733,706,
Japanese Patent Application Laid-Open No. Sho 54-17833 discloses a method of reducing the density by decoloring by light irradiation.

When an antihalation dye is used in the present invention, the dye has a desired absorption in a desired range, has a sufficiently low absorption in the visible region after treatment, and has a desirable absorbance spectrum shape of the back layer. Any compound can be used as long as it is possible. For example, the following are disclosed, but the present invention is not limited thereto. As a single dye, JP-A-59-56458, JP-A-2-216140, 7-13
No. 295, No. 7-11432, U.S. Pat.No.5,380,635, JP-A-2-688539, page 13, lower left column, line 1 to page 14, lower left column
On the ninth line, JP-A-3-24539, there are compounds described in the lower right column of page 14 to the lower right column of page 16, and as the dye which can be decolorized by the treatment, JP-A Nos. 52-139136 and 53-132334. , 56-501480, 5
7-16060, 57-68831, 57-101835, 59-18243
6, JP-A-7-36145, JP-A-7-199409, JP-B-48-33692
No. 50-16648, Japanese Patent Publication No. 2-41734, U.S. Patent 4,088,4
No. 97, 4,283,487, 4,548,896 and 5,187,049.

In the present invention, suitable binders for the back layer are transparent or translucent, generally colorless, and include natural polymer synthetic resins, polymers and copolymers, and other film-forming media such as: gelatin, gum arabic, and poly (vinyl). (Alcohol), hydroxyethyl cellulose, cellulose acetate, cellulose acetate butyrate, poly (vinyl pyrrolidone), casein, starch, poly (acrylic acid), poly (methyl methacrylic acid), poly (vinyl chloride), poly (methacrylic acid), copoly (Styrene-maleic anhydride), copoly (styrene-acrylonitrile), copoly (styrene-butadiene), poly (vinylacetal) s (e.g., poly (vinylformal) and poly (vinylformal))
(Vinyl butyral)), poly (ester) s, poly (urethanes), phenoxy resin, poly (vinylidene chloride), poly (vinylidene chloride)
(Epoxides), poly (carbonates), poly (vinyl acetate), cellulose esters, and poly (amides). The binder may be coated from water or an organic solvent or emulsion.

When the photothermographic material of the present invention is a one-sided photosensitive material, a matting agent is added to the surface protective layer of the photosensitive emulsion layer and / or the back layer or the surface protective layer of the back layer to improve transportability. May be. The matting agent is generally fine particles of an organic or inorganic compound insoluble in water. Any matting agent can be used, for example, US Pat.
939,213, 2,701,245, 2,322,037, 3,262,7
No. 82, No. 3,539,344, No. 3,767,448, etc., the organic matting agent described in each specification, No. 1,260,772, No. 2,192,241, No.
3,257,206, 3,370,951, 3,523,022, 3,76
Those well-known in the art, such as inorganic matting agents described in each specification such as 9,020, can be used. For example, specifically, examples of organic compounds that can be used as a matting agent include, as examples of water-dispersible vinyl polymers, polymethyl acrylate, polymethyl methacrylate, polyacrylonitrile, acrylonitrile-α-methylstyrene copolymer, and polystyrene. , Styrene-divinylbenzene copolymer, polyvinyl acetate, polyethylene carbonate, polytetrafluoroethylene, etc., examples of cellulose derivatives such as methylcellulose, cellulose acetate, cellulose acetate propionate, etc., and starch derivatives such as carboxy starch, carboxynitrophenyl Starch, urea-formaldehyde-starch reactant, etc.
Gelatin hardened with a known hardener and hardened gelatin coacervated into microcapsule hollow granules can be preferably used. Examples of the inorganic compound include silicon dioxide, titanium dioxide, magnesium dioxide, aluminum oxide, barium sulfate, calcium carbonate, silver chloride desensitized by a known method, silver bromide, glass, and diatomaceous earth. The above matting agents can be used by mixing different types of substances as necessary. The size and shape of the matting agent are not particularly limited, and those having an arbitrary particle size can be used. In practicing the present invention, it is preferable to use one having a particle size of 0.1 μm to 30 μm. Further, the particle size distribution of the matting agent may be narrow or wide. On the other hand, since the matting agent greatly affects the haze and surface gloss of the photosensitive material, the particle size, shape, and particle size distribution can be adjusted as needed during the preparation of the matting agent or by mixing a plurality of matting agents. preferable.

In the present invention, it is a preferred embodiment to add a matting agent to the backing layer. The matting degree of the backing layer is preferably Beck smoothness of 1200 seconds or less and 10 seconds or more, more preferably 700 seconds or less and 50 seconds or more. It is. In the present invention, the matting agent is preferably contained in the layer functioning as the outermost surface layer or the outermost surface layer of the light-sensitive material, or a layer close to the outer surface, and is contained in a layer acting as a so-called protective layer. Is preferred. The degree of matting of the emulsion surface protective layer may be any value as long as stardust failure does not occur, but the Beck smoothness is preferably 500 seconds or more and 10,000 seconds or less, particularly preferably 500 seconds or more and 2,000 seconds or less.

The photothermographic emulsion used in the present invention comprises one or more layers on a support. One layer is composed of organic silver salt, silver halide, developer and binder,
As well as optional additional materials such as toning agents, coating aids and other auxiliaries. The two-layer configuration requires that the first emulsion layer (usually the layer adjacent to the base) contain an organic silver salt and silver halide and the second layer or both layers contain some other components. No. However, a two-layer construction comprising a single emulsion layer containing all components and a protective topcoat is also contemplated. The construction of a multicolor photothermographic material may include a combination of these two layers for each color, and may include all components in a single layer as described in U.S. Pat.No. 4,708,928. Is also good.
In the case of a multi-dye multi-color photosensitive heat-developable photographic material, each emulsion layer is
Generally, they are kept distinct from one another by using a functional or non-functional barrier layer between each photosensitive layer, as described in US Pat. No. 4,460,681. U.S. Pat.Nos. 4,460,681 and 4,374,921 show a backside resistive heating layer as shown in U.S. Pat.
ating layer) can also be used in the photothermographic image system.

A hardening agent may be used for each layer such as a photosensitive layer, a protective layer and a back layer in the photothermographic material of the present invention. Examples of the hardener include U.S. Pat.No.4,281,060, polyisocyanates described in JP-A-6-208193, epoxy compounds described in U.S. Pat.No.4,791,042, JP-A-62-89048. For example, vinyl sulfone compounds described in US Pat. In the present invention, a surfactant may be used for the purpose of improving coating properties and charging. As the surfactant, any surfactant such as nonionic, anionic, cationic, and fluorine can be used as appropriate. Specifically, JP-A-62-170950, U.S. Patent
Fluoropolymer surfactants described in 5,380,644 and the like,
JP-A-60-244945, fluorine-based surfactants described in JP-A-63-188135, etc., polysiloxane-based surfactants described in U.S. Pat. Examples thereof include a polyalkylene oxide and an anionic surfactant.

The heat-developable photographic emulsion of the present invention can be generally coated on various supports. Typical supports include polyester films, primed polyester films, poly (ethylene terephthalate) films, polyethylene naphthalate films, cellulose nitrate films, cellulose ester films, poly (vinyl acetal) films, polycarbonate films and related or resinous Materials, as well as glass,
Including paper, metal, etc. Flexible substrates, in particular coated with partially acetylated or baryta and / or α-olefin polymers, especially polymers of C 2-10 α-olefins such as polyethylene, polypropylene, ethylene-butene copolymers A coated paper support is typically used. The support may be transparent or opaque, but is preferably transparent. Among these, polyethylene terephthalate biaxially stretched to about 75 to 200 μm is particularly preferred.

On the other hand, when the plastic film is passed through a heat developing machine at a temperature of 80 ° C. or higher, the dimensions of the film generally expand and contract. If the processed material is used for printing plate making,
This expansion and contraction is a serious problem when performing precision multicolor printing.
Therefore, in the present invention, it is preferable to use a film having a small dimensional change, which is designed to reduce internal strain remaining in the film at the time of biaxial stretching and eliminate thermal shrinkage distortion generated during thermal development. For example, polyethylene terephthalate, which is heat-treated at 100 to 210 ° C. before coating the photographic emulsion for thermal development, is preferably used. Those having a high glass transition point are also preferable, and polyether ethyl ketone, polystyrene, polysulfone, polyethersulfone,
Polyarylate, polycarbonate and the like can be used.

The photothermographic material of the present invention may contain, for example, a soluble salt (eg, chloride, nitrate, etc.) for preventing electrification.
Evaporated metal layers, U.S. Pat.Nos. 2,861,056 and 3,206,3
No. 12 ionic polymer or U.S. Pat.
Insoluble inorganic salts as described in 3,428,451, JP-A-60-25
It may have a layer containing fine particles of tin oxide described in JP-A Nos. 2349 and 57-104931. A method for obtaining a color image by using the photothermographic material of the present invention is described in JP-A-7-1329.
No. 5, page 10, left column, line 43 to 11 left column, line 40. In addition, as a stabilizer for color dye images, UK Patent No.
No. 1,326,889, U.S. Pat.Nos. 3,432,300 and 3,698,909
No. 3,574,627, No. 3,573,050, No. 3,764,33
No. 7 and No. 4,042,394.

The photothermographic emulsions used in this invention can be coated by various coating operations including dip coating, air knife coating, flow coating or extrusion coating using a hopper of the type described in US Pat. No. 2,681,294. . If desired, two or more layers can be coated simultaneously by the methods described in US Pat. No. 2,761,791 and British Patent No. 837,095. Additional layers in the photothermographic material of the present invention, for example, a dye-receiving layer for receiving a transfer dye image,
If reflective printing is desired, it can include an opacifying layer, a protective topcoat layer, a primer layer known in the photothermographic art, and the like. The light-sensitive material of the present invention is preferably capable of forming an image with only one light-sensitive material, and it is preferable that a functional layer required for image formation such as an image receiving layer does not become another light-sensitive material.

In the present invention, the exposure apparatus used for imagewise exposure may be any apparatus capable of performing exposure with an exposure time of less than 10 ^-7 seconds.
D), an exposure apparatus using a Light Emitting Diode (LED) as a light source is preferably used. In particular, LD is more preferable in terms of high output and high resolution. Any of these light sources may be used as long as it can generate light of an electromagnetic wave spectrum in a target wavelength range. For example, for LD,
Dye lasers, gas lasers, solid-state lasers, semiconductor lasers, and the like can be used. The exposure is performed by overlapping the light beams of the light source, and the overlap means that the sub-scanning pitch width is smaller than the beam diameter. For example, the overlap can be quantitatively represented by FWHM / sub-scanning pitch width (overlap coefficient) when the beam diameter is represented by a half width of beam intensity (FWHM). In the present invention, the overlap coefficient is preferably 0.2 or more.

The scanning method of the light source of the exposure apparatus used in the present invention is not particularly limited, and a cylinder outer surface scanning method, a cylinder inner surface scanning method, a plane scanning method, or the like can be used. Also,
The channel of the light source may be a single channel or a multi-channel, but in the case of a cylindrical outer surface type, a multi-channel is preferably used. The photothermographic material of the present invention has a low haze at the time of exposure and tends to cause interference fringes.
Examples of the interference fringe prevention technology include a technology disclosed in Japanese Patent Application Laid-Open No. HEI 5-113548 and the like, in which a laser beam is obliquely incident on a photosensitive material, and a technology disclosed in International Publication WO95 / 31754 and the like. Methods using a mode laser are known, and it is preferable to use these techniques.

The heat development step in the image formation of the photothermographic material of the present invention may be performed by any method.
Usually, the photosensitive material exposed imagewise is heated and developed. As a preferred embodiment of the thermal developing machine used,
Japanese Patent Publication No. 5-56499, Patent Publication No. 684453, JP-A-9-292695, JP-A-9-297385 and International Publication WO95 / 30934 as a type in which a photothermographic material is brought into contact with a heat source such as a heat roller or a heat drum. No. 7-13294, International publication WO97 /
No. 28489, 97/28488 and 97/28487. A particularly preferred embodiment is a non-contact type thermal developing machine. The preferred development temperature is 80 to 250 ° C, more preferably 100 to 140 ° C. The development time is preferably from 1 to 180 seconds, more preferably from 10 to 90 seconds. As a method for preventing processing unevenness due to a dimensional change during thermal development of the photothermographic material of the present invention, after heating for 5 seconds or more so that an image does not appear at a temperature of 80 ° C. or more and less than 115 ° C.,
A method of forming an image by thermal development at 10 ° C. or more and 140 ° C. or less (a so-called multi-stage heating method) is effective.

FIG. 1 shows an example of the configuration of a heat developing machine used for the heat developing process of the photothermographic material of the present invention. FIG. 1 is a side view of the heat developing machine. The heat developing machine shown in FIG. 1 carries a pair of carry-in rollers 11 (a lower roller is a heat roller) for carrying the heat-developable photosensitive material 10 into a heating section while correcting and pre-heating the heat-developable photosensitive material 10 in a planar shape, and a photothermographic material after thermal development after thermal development. It has an unloading roller pair 12 that unloads the material 10 from the heating unit while correcting it into a planar shape. The photothermographic material 10 is thermally developed while being transported from the carry-in roller pair 11 to the carry-out roller pair 12. The photothermographic material 10 during this thermal development
A plurality of rollers 13 are installed on the side where the surface having the image forming layer contacts, and a non-woven fabric (for example, made of polyphenylene sulfite or Teflon) or the like is provided on the side where the back surface contacts the opposite side. The laminated smooth surface 14 is provided. The back surface of the photothermographic material 10 is conveyed by sliding on the smooth surface 14 by driving a plurality of rollers 13 that come into contact with the surface having the image forming layer.
As a heating means, a heater 15 is provided at an upper portion of the roller 13 and a lower portion of the smooth surface 14 so as to be heated from both sides of the photothermographic material 10. As a heating means in this case, a plate heater or the like can be used. Although the clearance between the roller 13 and the smooth surface 14 differs depending on the member of the smooth surface,
The clearance is appropriately adjusted so that the photothermographic material 10 can be conveyed. Preferably it is 0 to 1 mm.

Material of Roller 13 Surface and Smooth Surface 1
The member 4 is durable at high temperature and may be anything as long as it does not hinder the conveyance of the photothermographic material 10, but the material of the roller surface is made of silicon rubber, and the member of the smooth surface is made of aromatic polyamide or Teflon (PTFE). Non-woven fabrics are preferred. It is preferable to use a plurality of heaters as the heating means and to set the heating temperature freely. The preheating section upstream of the heat development processing section has a temperature and time lower than the heat development temperature (for example, about 10 to 20 ° C.) and sufficient for evaporating the amount of water in the photothermographic material. It is desirable to set the temperature so as to prevent development unevenness at a temperature higher than the glass transition temperature (Tg) of the support of the photothermographic material 10. Further, a guide plate 16 is provided downstream of the heat development processing section B, and a slow cooling section C is further provided. The guide plate is preferably made of a material having low thermal conductivity, and is preferably cooled gradually.

Although the above has been described with reference to the illustrated examples, the invention is not limited to this. For example, the thermal developing machine used in the present invention, such as that described in JP-A-7-13294, may have various structures. In the case of the multi-stage heating method preferably used in the present invention, in the above-described apparatus, two or more heat sources having different heating temperatures may be provided, and heating may be performed continuously at different temperatures.

[0128]

The present invention will be described more specifically with reference to the following examples. The materials, amounts, proportions,
The operation and the like can be appropriately changed without departing from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the following specific examples. <Example 1> 1. Preparation of silver halide emulsion (Emulsion A) 11 g of alkali-treated gelatin (2700 ppm or less as calcium content), 30 mg of potassium bromide, and 10 mg of sodium benzenethiosulfonate were dissolved in 700 ml of water, and the pH was adjusted to 5.0 at a temperature of 40 ° C. After combining, 159m of aqueous solution containing 18.6g of silver nitrate
l and potassium bromide at 1 mol / l (NH ₄ ) ₂ RhCl ₅
(H ₂ O) at 5 × 10 ⁻⁶ mol / L and K ₃ IrCl ₆
An aqueous solution containing 2 × 10 ⁻⁵ mol / l was added over 6 minutes and 30 seconds by the control double jet method while maintaining the pAg at 7.7. Then, 476 ml of an aqueous solution containing 55.5 g of silver nitrate, 1 mol / l of potassium bromide and 2 × 10 ₃ of K ₃ IrCl ₆ were added.
^An aqueous solution of a halogen salt containing ^-5 mol / l was added over 28 minutes and 30 seconds by a control double jet method while maintaining the pAg at 7.7. Thereafter, the pH was lowered to cause coagulation and sedimentation, followed by desalting treatment. 0.17 g of compound A, low molecular weight gelatin having an average molecular weight of 15,000 (calcium content: 20 ppm or less) 51.
The solution was adjusted to pH 5.9 and pAg 8.0 by adding 1 g. The obtained particles were cubic particles having an average particle size of 0.08 μm, a projected area variation coefficient of 9%, and a (100) plane ratio of 90%. The silver halide grains thus obtained were heated to 60 ° C., and 76 μmol of sodium benzenethiosulfonate was added per 1 mol of silver, and 3 minutes later, 71 μmol of triethylthiourea was added, followed by aging for 100 minutes.
After adding 5 × 10 ⁻⁴ mol of hydroxy-6-methyl-1,3,3a, 7-tetrazaindene, the temperature was lowered to 40 ° C.
Thereafter, while maintaining the temperature at 40 ° C., 12.8 × 10 ⁻⁴ mol of the following sensitizing dye A and 6.4 × 10 ⁻³ mol of the compound B per 1 mol of silver halide are added with stirring, and after 20 minutes, 30 mol The mixture was rapidly cooled to ° C. to complete the preparation of silver halide emulsion A.

[0129]

Embedded image

[0130] 2. Preparation of Organic Acid Silver Dispersion <Organic Acid Silver A
> Henkel Behenic acid (Product name: Edenor C22-85R) 8
A mixture of 7.6 g, 423 ml of distilled water, 49.2 ml of 5N-NaOH aqueous solution and 120 ml of tert-butyl alcohol was stirred and reacted at 75 ° C. for 1 hour to obtain a sodium behenate solution. Separately, silver nitrate
206.2 ml of an aqueous solution of 40.4 g was prepared and kept at 10 ° C. 63
A reaction vessel containing 5 ml of distilled water and 30 ml of tert-butyl alcohol was kept at 30 ° C., and while stirring, the entire amount of the sodium behenate solution and the entire amount of the silver nitrate aqueous solution were kept at a constant flow rate for 62 minutes, 10 seconds and 60 minutes, respectively. Added over minutes. At this time, only the aqueous solution of silver nitrate was added for 7 minutes and 20 seconds after the addition of the aqueous solution of silver nitrate, and then the addition of the sodium behenate solution was started.After the completion of the addition of the aqueous solution of silver nitrate, only the sodium behenate solution was added for 9 minutes and 30 seconds. It was made to be added. At this time, the temperature in the reaction vessel was set at 30 ° C., and the liquid temperature was controlled so as not to rise. In addition, the piping of the addition system of the sodium behenate solution is kept warm by steam tracing,
The amount of steam was controlled so that the liquid temperature at the outlet at the tip of the addition nozzle was 75 ° C. The piping of the silver nitrate aqueous solution addition system was kept warm by circulating cold water outside the double pipe. The addition position of the sodium behenate solution and the addition position of the aqueous silver nitrate solution were arranged symmetrically with respect to the stirring axis, and were adjusted to a height such that they did not come into contact with the reaction solution.
After the completion of the addition of the sodium behenate solution, the mixture was allowed to stir at the same temperature for 20 minutes, and then cooled to 25 ° C. Thereafter, the solid content was separated by suction filtration, and the solid content of the filtrate had a conductivity of 30 μS / cm.
And washed with water. The solid thus obtained was stored as a wet cake without drying. When the morphology of the obtained silver behenate grains was evaluated by electron micrographing, the average projected area diameter was 0.52 μm, and the average grain thickness was 0.14 μm.
m, scale-like crystals with a coefficient of variation of 15% of the average equivalent sphere diameter.

Next, a dispersion of silver behenate was prepared by the following method. To a wet cake having a dry solid content of 100 g, 7.4 g of polyvinyl alcohol (trade name: PVA-217, average degree of polymerization: about 1700) and water are added, and the total amount is 385 g.
And then predispersed with a homomixer. Next, the pre-dispersed stock solution was adjusted three times by adjusting the pressure of a dispersing machine (trade name: Microfluidizer M-110S-EH, manufactured by Microfluidics International Corporation, using a G10Z interaction chamber) to 1750 kg / cm2. After treatment, a silver behenate dispersion was obtained. In the cooling operation, a coiled heat exchanger was mounted before and after the interaction chamber, and the temperature of the refrigerant was adjusted to a desired dispersion temperature. The silver behenate particles contained in the silver behenate dispersion thus obtained have a volume-weighted average diameter of 0.52 μm,
The particles had a coefficient of variation of 15%. Particle size measurement is Mal
Vern Instruments Ltd. made MasterSizerX. When evaluated by electron microscopy, the ratio of the long side to the short side is
The particle had a thickness of 0.14 μm and an average aspect ratio of 5.1 (the ratio of the circle equivalent diameter of the projected area of the particle to the particle thickness) was 5.1.

[0132] 3. 1,1-bis (2-hydroxy-3,5-dimethyl
Ruphenyl) -3,5,5-trimethylhexane: reducing agent solid fine
Preparation of particle dispersion 1,1-bis (2-hydroxy-3,5-dimethylphenyl) -3,5,5-
To 25 g of trimethylhexane, 25 g of a 20% aqueous solution of MP-203 made by Kuraray Co., Ltd., 0.1 g of Safinol 104E manufactured by Nissin Chemical Co., Ltd., 2 g of methanol and 48 ml of water were added and stirred well. The slurry was left for 3 hours. Then 1
360 g of zirconia beads having a diameter of 360 mm were prepared, put into a vessel together with the slurry, and dispersed with a dispersing machine (1 / 4G sand grinder mill: manufactured by Imex Co., Ltd.) for 3 hours to prepare a dispersion of solid fine particles of a reducing agent. The particle size is 80% by weight of the particles
It was 0.3 μm or more and 1.0 μm or less.

[0133] 4. Solid fine particles of polyhalogen compounds
Preparation of powder For 25 g of polyhalogen compound-A, 5 g of MP-203 of Kuraray Co., Ltd., 0.21 g of compound C, and 70 g of water
Was added and stirred well, then 200 g of 0.5 mm zirconia silicate beads were prepared and placed in a vessel together with the slurry, and dispersed for 5 hours with a dispersing machine (1 / 16G sand grinder mill: manufactured by Imex Co., Ltd.) A solid fine particle dispersion A was prepared. Particle size, 80% by weight of particles is 0.3μm or more
It was 1.0 μm or less. To 20 g of the polyhalogen compound-B, 2 g of MP-203, a polymer manufactured by Kuraray Co., Ltd., 2 g of the MP polymer, 0.17 g of the compound C and 78 g of water were added, and the mixture was stirred well. Dispersion B was prepared and had a similar particle size.

[0134] 5. 6-iso-Propylphthalazine solid fine
Preparation of Particle Dispersion For 5 g of 6-iso-propylphthalazine, 4 g of MP-203, a polymer manufactured by Kuraray Co., Ltd., 0.14 g of compound C, and 91 g of water were added, and the mixture was thoroughly stirred. A was prepared. The particle diameter was such that 80% by weight of the particles were 0.3 μm or more and 1.0 μm or less.

[0135] 6. Preparation of Solid Fine Particle Dispersion of Compound Z To 10 g of Compound Z, 3.2 g of MP-203 (manufactured by Kuraray Co., Ltd.) and 87 ml of water were added, stirred well, and left as a slurry for 3 hours. Thereafter, a solid fine particle dispersion of the compound Z was prepared in the same manner as in the preparation of the reducing agent solid fine particle dispersion. Particle size: 80% by weight of particles is 0.3μm or more
It was 1.0 μm or less.

[0136] 7. Preparation of Solid Fine Particle Dispersion of Nucleating Agent To 10 g of the nucleating agent described in Table 1, 2.5 g of polyvinyl alcohol (PVA-217 manufactured by Kuraray Co., Ltd.) and 87.5 g of water were added and stirred well to form a slurry. Left for 3 hours. Then 0.5
240 g of zirconia beads having a diameter of 240 mm was prepared and placed in a vessel together with the slurry, and dispersed with a disperser (1 / 4G sand grinder mill: manufactured by Imex Co., Ltd.) for 10 hours to prepare a solid fine particle dispersion. The particle size is 80% by weight of the particles is 0.1%
It was not less than μm and not more than 1.0 μm, and the average particle size was 0.5 μm.

[0137] 8. Preparation of Emulsion Layer Coating Solution The following binder, material, and silver halide emulsion A were added to 1 mol of silver of the organic acid silver microcrystal dispersion prepared above, and water was added. Liquid. Binder; Luckstar 3307B 397 g as solid content (manufactured by Dainippon Ink and Chemicals, Inc .; glass transition temperature of 17 ° C. with SBR latex) 1,1-bis (2-hydroxy-3,5-dimethylphenyl) -3,5 , 5-Trimethylhexane 149g as solid content Polyhalogen compound-A 34.8g as solid content Polyhalogen compound-B 9.0g as solid content Sodium ethylthiosulfonate 0.30g Benzotriazole 1.04g Polyvinyl alcohol (Kuraray Co., Ltd. PVA- 235) 10.8 g 6-iso-propylphthalazine 15.0 g Sodium dihydrogen orthophosphate dihydrate 0.37 g Compound Z 9.7 g as solids Nucleating agent Types shown in Table 1. However, the amount is 0.03 mol as a solid content. The coating amount at which the optical density of the dye A 783 nm becomes 0.3 (0.37 g as a standard) 0.06 mol as the silver halide emulsion A Ag amount

[0138]

Embedded image

[0139] 9. Preparation of Coating Solution for Lower Emulsion Surface Protective Layer Methyl methacrylate / styrene / 2-ethylhexyl acrylate / 2-hydroxyethyl methacrylate / acrylic acid = 58.9 / 8.6 / 25.4 / 5.1 / 2 (wt%) polymer latex solution (copolymer Water was added to 956 g of a glass transition temperature of 46 ° C. (calculated value), a solid content concentration of 21.5%, a compound D as a film-forming aid at 15 wt% based on the solid content of the latex, and an average particle diameter of 116 nm. g, the compound and the amount of the formula (S) shown in Table 1, 1.98 g of a matting agent (polystyrene particles, average particle size 7 μm) and 23.6 g of polyvinyl alcohol (Kuraray Co., Ltd., PVA-235) were added. In addition, a coating solution was prepared.

[0140] 10. Preparation of Coating Solution for Emulsion Upper Protective Layer Methyl methacrylate / styrene / 2-ethylhexyl acrylate / 2-hydroxyethyl methacrylate / acrylic acid = 58.9 / 8.6 / 25.4 / 5.1 / 2 (wt%) polymer latex solution (copolymer Water is added to 630 g of a glass transition temperature of 46 ° C. (calculated value), a solid concentration of 21.5%, and a compound D as a film-forming aid containing 15 wt% based on the solid content of the latex and an average particle diameter of 72 nm. 6.30 g of a 30 wt% solution (manufactured by Chukyo Yushi Co., Ltd., Cellosol 524), 0.72 g of compound E, 7.95 g of compound F, the compound and amount of the formula (S) shown in Table 1, a matting agent (polystyrene particles, average particle size)
7 μm) 1.18 g and polyvinyl alcohol (Kuraray Co., Ltd.)
Co., Ltd., PVA-235) (8.30 g) and water were further added to prepare a coating solution.

[0141]

Embedded image

[0142] 11. PET support with backing / priming layer
Preparation of support (1) Support PET (intrinsic viscosity) = 0.66 (measured at 25 ° C. in phenol / tetrachloroethane = 6/4 (weight ratio)) using terephthalic acid and ethylene glycol according to a conventional method. I got After pelletizing this, dried at 130 ° C. for 4 hours, melted at 300 ° C., extruded from a T-die, and quenched,
An unstretched film having a thickness of 120 μm after heat setting was prepared. Using rolls with different peripheral speeds,
The film was longitudinally stretched 3.3 times and then stretched 4.5 times with a tenter. The temperatures at this time were 110 ° C. and 130 ° C., respectively. After that, it was heat-set at 240 ° C. for 20 seconds and relaxed 4% in the lateral direction at the same temperature. Then, after slitting the chuck part of the tenter, knurling is performed on both ends, and 4.8 kg / cm2
Rolled up. In this way, width 2.4m, length 3500m,
A roll having a thickness of 120 μm was obtained.

(2) Undercoat layer (a) Polymer latex- (1) (a core-shell type latex having a core portion of 90% by weight and a shell portion of 10% by weight, wherein the core portion is vinylidene chloride / methyl acrylate / methyl methacrylate / acrylonitrile / Acrylic acid = 93/3/3 / 0.9 / 0.1 (% by weight), shell part: vinylidene chloride / methyl acrylate / methyl methacrylate / acrylonitrile / acrylic acid = 88/3/3/3/3 (% by weight) from consisting weight average molecular weight polymer latex 38000) solid content as 3.0 g / m ² 2,4-dichloro-6-hydroxy -s- triazine 23 mg / m ² matting agent (polystyrene, mean particle size 2.4 [mu] m) 1.5 mg / m ^Two

(3) Undercoat layer (b) Deionized gelatin (Ca ²⁺ content 0.6 ppm, jelly strength 230 g) 50 mg / m ²

(4) Conductive layer Julimer ET-410 (manufactured by Nippon Pure Chemical Co., Ltd.) 96 mg / m ² alkali-treated gelatin (molecular weight of about 10,000, Ca ²⁺ content 30 ppm) 42 mg / m ² deionized gelatin (Ca ^{2 +} content 0.6 ppm) 8 mg / m ² compound A 0.2 mg / m ² polyoxyethylene phenyl ether 10 mg / m ² Sumitex resin M-3 (water-soluble melamine compound, Sumitomo chemical Co., Ltd.) 18 mg / m ² dye A Amount of coating at which the optical density of 783 nm becomes 1.2 SnO ₂ / Sb (9/1 weight ratio, acicular fine particles, major axis / minor axis = 20 to 30, manufactured by Ishihara Sangyo Co., Ltd.) 160 mg / m ² matting agent ( Polymethyl methacrylate, average particle size 5μm) 7mg / m ²

(5) Protective Layer Polymer Latex- (2) (Methyl methacrylate / styrene / 2-ethylhexyl acrylate / 2-hydroxyethyl methacrylate / acrylic acid = 59/9/26/5/1 (weight% copolymer) )) 1000mg / m ² polystyrenesulfonate solid basis (molecular weight 1000~5000) 2.6mg / m ² Cellosol 524 (Chukyo Yushi (Co.)) 25mg / m ² Sumitex resin M-3 (water-soluble melamine compound, Sumitomo 218 mg / m ²

(6) Preparation of PET support with back / undercoat layer Undercoat layer (a) and undercoat layer (b) were sequentially applied to both sides of the support (base), and dried at 180 ° C. for 4 minutes, respectively. . Then, the undercoat layer (a) and the undercoat layer (b) were applied, and a conductive layer and a protective layer were sequentially applied to one surface on one side.
After drying for minutes, a PET support with a back / subbing layer was prepared. The dry thickness of the undercoat layer (a) was 2.0 μm.

(7) Heat treatment for transportation (7-1) Heat treatment PET with back / undercoat layer produced in this way
Place the support in a heat treatment zone with a total length of 200 m set at 160 ° C,
It was transported at a tension of 3 kg / cm ² and a transport speed of 20 m / min. (7-2) Post heat treatment Following the heat treatment, post heat treatment was performed by passing through a zone at 40 ° C for 15 seconds, and winding was performed. The winding tension at this time is 10
kg / cm ² .

[0149]

Embedded image

[0150] 12. Preparation of a photothermographic material The above-mentioned undercoat layer (a) and the undercoat layer on the side of the PET support coated with the undercoat layer (b) were coated with the emulsion layer coating solution described above in an amount of 1.7 g of silver.
/ m ² . Further, the coating solution for the lower protective layer on the emulsion surface was simultaneously coated with the emulsion coating solution so that the coating amount of the solid content of the polymer latex was 1.31 g / m ² . At this time, the water content defined by the above equation is 200%
Drying conditions are as follows: dry bulb temperature 71 ° C, dew point 23 ° C
For 1 minute (described in Table 1), and dried and film-formed at a dry-bulb temperature of 65 ° C. and a dew point of 21 ° C. during reduced-rate drying. Thereafter, the coating solution for the upper protective layer on the emulsion surface was applied thereon so that the coating amount of the solid content of the polymer latex was 3.02 g / m ² , to produce a photothermographic material. At this time, drying was performed at a dry bulb temperature of 75 ° C. and a dew point of 22 ° C. for T2 minutes under a drying condition up to a water content of 200%, and drying and film formation were performed at a dry bulb temperature of 65 ° C. and a dew point of 21 ° C. during reduced rate drying. The film surface pH on the image forming side of the obtained photothermographic material was 4.9 and the Beck smoothness was 660 seconds. The film surface pH on the opposite side was 5.9 and the Beck smoothness was 560 seconds.

13. Evaluation of photographic performance (exposure processing) The obtained photothermographic material was subjected to a beam diameter (FWHM of 1/2 of beam intensity) of 12.56 μm and a laser output of 50 m.
W, using a single-channel cylindrical inner surface laser exposure device equipped with a semiconductor laser with an output wavelength of 783 nm, adjust the exposure time by changing the number of rotations of the mirror, adjust the exposure amount by changing the output value, 2 Exposure was performed in × 10 ⁻⁸ seconds. The overlap coefficient at this time was set to 0.449. (Thermal Development Processing) The exposed photothermographic material is heated using the thermal developing machine shown in FIG. 1 and the roller surface material of the thermal development processing section is made of silicon rubber, the smooth surface is made of Teflon non-woven fabric, and the preheating section 90-
A heat development process was performed at 100 ° C. for 5 seconds and a heat development processing unit at 120 ° C. for 20 seconds. The temperature accuracy in the width direction was ± 1 ° C. (Evaluation of photographic performance) Macbeth TD904
The measurement was performed using a densitometer (visible density). The result of the measurement was evaluated by the relative value of Dmin and the reciprocal of the sensitivity (the reciprocal of the ratio of the exposure amount giving a density 1.5 higher than Dmin, and the photothermographic material 4 described in Table 1 was evaluated.
100). As for the evaluation of the storage stability, two sets of the photothermographic material at 25.degree. C. and a humidity of 30% RH were trimmed into a sheet state, and three sheets were placed in a moisture-proof bag. For 5 days and at 35 ° C for 20 days, then the photothermographic material before storage and 3 days after storage.
The above-described exposure and heat development were performed on the central portion (second sheet) of the stacked sheets, and Dmin and sensitivity were evaluated.

[0142] 14. Evaluation of film brittleness After leaving the raw sample in an atmosphere of 25 ° C. and 10% RH for 2 hours, the average of the points where cracks first occurred on the side including the image forming layer was determined in the same manner as in ISO 6077 “Wedgebrittleness test”. The value (mm) was determined and evaluated as a relative value (the photothermographic material 4 shown in Table 1 was taken as 100, and the lower the value, the better).

[0153] 15. Results Table 1 shows the results of the above evaluations performed for each photothermographic material.

[0154]

[Table 1]

As is clear from the data of the samples Nos. 1 to 4 and Nos. 17 to 19 which do not contain the formalin scavenger in Table 1, the formalin scavenger free system has no drying dependency. However, sample No. 5 ~ 16, 20 ~
According to the data of 35, in the system to which the formalin scavenger was added, formalin resistance was improved by shortening the time (T1 or T2) from application to 200% or less of water content, particularly to 5 minutes or less. You can see that. In addition, if the amount of formalin scavenger is increased, there is an effect on formaldehyde gases, but the film brittleness tends to be inferior. When the present invention is used, the effect can be exhibited without necessarily increasing the amount of the scavenger, and good performance with low Dmin (fog), little increase in fog during storage, and small sensitivity fluctuation can be obtained. Understand. From the above, the effect of the present invention is clear.

<Example 2> The photothermographic materials 4 (comparative) and 23 (invention) of Example 1 were described in JP-A-6-214350.
The roll packaging described in the item No. was applied, and light-shielding roll packaging (product form packaging) with a width of 61 m and a length of 59 m was performed. The humidity in the package of this product form packaging was estimated to be 25% RH at 25 ° C. from the water content of the photothermographic material. In the same manner as in Example 1, storage stability tests were carried out on the product form packaging at 45 ° C. for 5 days and at 35 ° C. for 20 days. The obtained results almost reproduced the results of Example 1, and it was confirmed that the photothermographic material 23 of the present invention exhibited a small increase in Dmin and a small change in sensitivity even in a product form.
Therefore, the effect of the present invention is clear.

[0157]

According to the present invention, fog is low especially for photoengraving, especially for scanners and imagesetters.
It has become possible to provide a photothermographic material capable of obtaining an image with little fog increase and sensitivity fluctuation during storage and having good film brittleness.

[Brief description of the drawings]

FIG. 1 is a side view illustrating a configuration example of a heat developing machine.

[Explanation of symbols]

 DESCRIPTION OF REFERENCE NUMERALS 10 photothermographic material 11 carry-in roller pair 12 carry-out roller pair 13 roller 14 smooth surface 15 heating heater 16 guide plate A preheating section B heat development processing section C slow cooling section

Claims (4)

[Claims] 1. A photothermographic material having a non-photosensitive silver salt, a photosensitive silver halide, a binder and a nucleating agent on a support, wherein the formaldehyde can be fixed by reacting with the formaldehyde. By applying a coating liquid containing at least one kind of compound, and drying under conditions that the time from the start of drying until the water content defined by the following formula reaches 200% is 5 seconds or more and 5 minutes or less. A photothermographic material comprising at least one layer to be formed on the support surface side where the image forming layer containing the photosensitive silver halide is present. (Equation 1) 2. The compound according to claim 1, wherein the compound is at least one compound represented by the following formula (S).
The photothermographic material according to the above. Embedded image [In the formula (S), X ¹ represents an oxygen atom or a = NH group.
R ¹ and R ² each independently represent a hydrogen atom, an acyl group, a hydrocarbon group or a carbamoyl group. However, when X ¹ is an oxygen atom, at least one of R ¹ and R ² is a hydrogen atom. L ¹ represents a divalent organic group necessary for forming a cyclic structure. ] 3. The heat according to claim 1, wherein 50% by weight or more of the binder in the image forming layer is a latex of a polymer having a glass transition temperature of −30 ° C. to 40 ° C. Developed photosensitive material. 4. At least one selected from a substituted alkene derivative represented by the following formula (1), a substituted isoxazole derivative represented by the following formula (2), and an acetal compound represented by the following formula (3): The photothermographic material according to any one of claims 1 to 3, wherein the compound is used as a nucleating agent. Embedded image [In the formula (1), R ¹¹ , R ¹² and R ¹³ each independently represent a hydrogen atom or a substituent, and Z represents an electron-withdrawing group or a silyl group. In the formula (1), R ¹¹ and Z, R ¹² and R ¹³ , R ¹¹ and R ¹² , and R ¹³ and Z may be mutually bonded to form a cyclic structure. In the formula (2), R ¹⁴ represents a substituent. In the formula (3), X and Y
Each independently represents a hydrogen atom or a substituent, and A and B each independently represent an alkoxy group, an alkylthio group, an alkylamino group, an aryloxy group, an arylthio group, an anilino group, a heterocyclic oxy group, a heterocyclic thio group or Represents a heterocyclic amino group. In the formula (3), X and Y, and A and B may be bonded to each other to form a cyclic structure. ]