JP2005070251A - Heat developable photosensitive material and image forming method for the heat developable photosensitive material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat developable photosensitive material which ensures no deterioration of image graininess, little falling of a matting agent, excellent scuffing resistance and little adhesion of photosensitive materials to each other, and to provide an image forming method for the heat developable photosensitive material. <P>SOLUTION: The heat developable photosensitive material has an image forming layer containing a photosensitive silver halide, a non-photosensitive organic silver salt, a reducing agent and a binder on at least one surface of a support, wherein a thickness of the image forming layer is 5-12 μm and one layer on a surface side of the support with the image forming layer contains a matting agent having a diameter corresponding to ≥30% of the thickness of the image forming layer. The image forming method for the heat developable photosensitive material is also provided. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a photothermographic material and an image forming method for the photothermographic material.

  In recent years, in the medical field, reduction of waste processing liquid has been strongly desired from the viewpoint of environmental protection and space saving. Therefore, the photosensitive heat for medical diagnosis and photographic technology that can be efficiently exposed by a laser image setter or a laser imager and can form a clear black image having high resolution and sharpness. There is a need for techniques relating to developed photographic materials. These photosensitive photothermographic materials can eliminate the use of solution processing chemicals and supply customers with a simpler heat development processing system that does not damage the environment.

  In the field of general image forming materials, an image having excellent sharpness and graininess is preferred, but in particular for medical images, fine depiction is required so as not to cause misdiagnosis. In addition, a cool black image is preferred for ease of diagnosis. At present, various hard copy systems using pigments and dyes such as inkjet printers and electrophotography are distributed as general image forming systems. However, there is no satisfactory output system for medical images.

  On the other hand, thermal image forming systems using organic silver salts have been presented in many documents. The photothermographic material used in the thermal image forming system has an image forming layer. Generally, the image forming layer has a catalytically active amount of a photocatalyst (eg, silver halide), a reducing agent, a reducible silver salt (eg, , An organic silver salt), and if necessary, a toning agent for controlling the tone of silver is dispersed in a matrix of the binder. The photothermographic material is heated to a high temperature (for example, 80 ° C. or higher) after image exposure, and is blackened by an oxidation-reduction reaction between silver halide or a reducible silver salt (functioning as an oxidizing agent) and a reducing agent. Form a silver image. The oxidation-reduction reaction is promoted by the catalytic action of the latent image of silver halide generated by exposure. Therefore, a black silver image is formed in the exposure area. Fuji Medical Dry Imager FM-DPL has been released as a medical image forming system using such a photothermographic material.

  The design of these photothermographic materials requires considerations specific to thermal development different from those of conventional photosensitive materials developed with a developing solution. In particular, during heat development, since heat of 80 to 140 ° C. is usually applied, a design different from the conventional one is required.

The photothermographic material is manufactured by a method in which each layer is applied and dried while a long and wide film is conveyed, and finally wound up in a roll shape, in the same manner as a photosensitive material developed with a developer. Since the wound film is stored in roll form until the next process, the films may stick to each other due to temperature and humidity during storage and pressure due to their own weight. In addition, the films may rub against each other during contact with a roll being transported, during winding or unwinding, and the outermost surface of the film may be damaged. Furthermore, films after development may stick to each other due to temperature and humidity during storage or pressure due to their own weight.
In order to prevent such sticking and scratches, it has been conventionally known that it is effective to provide a matting agent on the film surface.

  However, when heat development is performed at a high temperature of 80 ° C. or higher, the matting agent is deformed during development, or the binder contained in the photothermographic material is softened by heat and the matting agent sinks into the layer. There was a problem that the effect of the agent was reduced. When the matting agent sinks and enters the image forming layer, there is a problem that pinholes are likely to occur after development (see, for example, Patent Document 1). Furthermore, the phenomenon that the matting agent peeled off during heat development occurred.

  As a method for reducing image unevenness during thermal development, a thermal development method using a plate heater method has been proposed (see, for example, Patent Document 2). In the plate-type heater system, development is performed while sliding the photosensitive material, and in this system in particular, the matting agent greatly affects the performance of the photothermographic material.

In this way, depending on the conditions during the heat development processing, the slipping property between the photosensitive material and the transport roller or processing member of the heat development processing device has changed, resulting in poor transport and uneven density. The technology to do it was anxious. In particular, in medical photosensitive materials, density unevenness leads to misdiagnosis of lesions when photographing each part of a living body, and therefore there has been a strong demand for photothermographic materials free from image defects, scratches, and deposits.
JP 2002-268179 A Japanese Patent Laid-Open No. 11-133572

  Accordingly, it is an object of the present invention to provide a photothermographic material in which the granularity of image quality is not deteriorated, the matting agent is less peeled off, the scratch resistance is excellent, and the photosensitive material is prevented from adhering to each other, and an image of the photothermographic material is provided. The forming method is to provide.

The object of the present invention has been achieved by the following photothermographic materials.
<1> A photothermographic material having an image forming layer containing photosensitive silver halide, non-photosensitive organic silver salt, a reducing agent and a binder on at least one surface of a support, wherein Any layer on the surface side having the image forming layer with respect to the support has a matting agent having a diameter of 30% or more with respect to the film thickness of the image forming layer. A photothermographic material characterized by the above.
<2> The photothermographic material according to <1>, wherein the coating amount of the matting agent is 20 mg / m ² or more and 250 mg / m ² or less.
<3> The photothermographic material according to <1> or <2>, wherein the image forming layer is provided only on one side of the support.
<4> The photothermographic material according to <1> or <2>, wherein the image forming layer is provided on both sides of the support.
<5> The photothermographic material according to any one of <1> to <4>, wherein the matting agent has a diameter of 30% to 120% of the film thickness of the image forming layer.
<6> The photothermographic material according to any one of <1> to <5>, wherein the binder has a glass transition temperature of 0 ° C. or higher and 80 ° C. or lower.
<7> The image forming method for a photothermographic material according to any one of <1> to <6>, wherein the conveyance speed of the photothermographic material during heat development is 10 mm / second or more. An image forming method of a photothermographic material characterized by the above.
<8> The photothermographic material image forming method according to any one of <1> to <6>, wherein the photothermographic material is thermally developed while sliding the photothermographic material. Image forming method.
<9> The image forming method of a photothermographic material according to claim 7, wherein the photothermographic material is thermally developed while sliding.

In order to improve the transportability of the photothermographic material, it is necessary that the matting agent does not sink into the layer. Depending on the type of binder, the matting agent can easily sink due to external pressure or heat. In order to avoid this, when the particle size of the matting agent is increased without limit, the matting agent is peeled off or a pinhole problem occurs. In addition, the granularity of the image quality becomes coarse, and it has been extremely difficult to balance the material properties of the light-sensitive material with the image quality.
Here, the present inventors examined the relationship between the image forming layer and the matting agent, and found that a very important relationship between the “film thickness” of the image forming layer and the “particle size” of the matting agent. Found that there is. As a result of further earnest research, the present invention <1> has been reached.
In particular, when the glass transition temperature of the binder of the image forming layer is 0 ° C. or higher and 80 ° C. or lower, the matting agent tends to sink into the layer. Even in such a case, the object of the present invention can be achieved by using the matting agent according to the present invention.
Furthermore, in the image forming method, development in a short time is required, and the speed of conveying the photosensitive material is increased. The photothermographic material of the present invention has good transportability and excellent image quality for rapid processing.

  According to the present invention, there are provided a photothermographic material having excellent scratch resistance and less adhesion between photosensitive materials, and an image forming method for the photothermographic material.

  The photothermographic material of the present invention is a photothermographic material having an image forming layer containing a photosensitive silver halide, a non-photosensitive organic silver salt, a reducing agent and a binder on at least one surface of a support, The film thickness of the image forming layer is 5 μm or more and 12 μm or less, and any layer on the side having the image forming layer with respect to the support has a diameter of 30% or more with respect to the film thickness of the image forming layer. Others are not particularly limited as long as the matting agent is contained.

  First, the layer structure of the photothermographic material of the present invention will be described, and then the components of each layer will be described.

1. Layer Structure The photothermographic material of the invention has at least one image forming layer, and the film thickness of the image forming layer is from 5 μm to 12 μm.
Usually, the non-photosensitive layer is composed of (a) a surface protective layer provided on the image forming layer (on the side farther from the support), (b) between the plurality of image forming layers or between the image forming layer and the surface. An intermediate layer provided between the protective layers, (c) an undercoat layer provided between the image forming layer and the support, and (d) a back layer provided on the opposite side of the image forming layer.
In the present invention, any layer on the side having the image forming layer with respect to the support contains a matting agent, and the diameter of the matting agent is 30% or more of the film thickness of the image forming layer. The layer containing the matting agent is preferably a non-photosensitive layer classified as (a).
In the present invention, as the non-photosensitive layer, the second surface protective layer (a), the intermediate layer (b), the undercoat layer (c) and the back layer (d) can be provided. . These may be each independently a single layer or a plurality of layers.

  Moreover, the layer which acts as an optical filter can be provided, and it is provided as the layer (a) or (b) of the non-photosensitive layer. The antihalation layer is provided on the photosensitive material as the layer (c) or (d).

  The photothermographic material of the present invention may be a single-sided type having an image forming layer only on one side of a support, or a double-sided type having image forming layers on both sides of a support. In the case of the single-sided type, it is preferable to have the back layer on the surface opposite to the side having the image forming layer (hereinafter referred to as the back surface) with respect to the support.

  The image forming layer in the present invention is provided on one or both sides of the support, and is composed of one or more layers on one side. In the case of a single layer, the image-forming layer contains an organic silver salt, a photosensitive silver halide, a reducing agent and a binder, and optionally contains additional materials such as toning agents, coating aids and other auxiliary agents. In the case of two or more layers, an organic silver salt and a light-sensitive silver halide are contained in the first image forming layer (usually a layer adjacent to the support), and some in the second image forming layer or both layers. Must contain other ingredients. The construction of a multicolor photosensitive photothermographic material may include a combination of these two layers for each color and all components in a single layer as described in US Pat. No. 4,708,928. May be included. In the case of multi-dye multicolor photosensitive photothermographic materials, each emulsion layer is generally functional or non-functional between each photosensitive layer as described in US Pat. No. 4,460,681. By using different barrier layers, they are distinguished from each other and held.

2. Components of each layer (matte agent)
The matting agent used in the present invention is generally fine particles of an organic or inorganic compound that is insoluble in water. Any matting agent can be used, for example, U.S. Pat. Nos. 1,939,213, 2,701,245, 2,322,037, 3,262,782, and 3,539. , 344, 3,767,448, etc., the organic matting agents described in the respective specifications, 1,260,772, 2,192,241, 3,257,206, 3, Those well known in the art such as the inorganic matting agent described in each specification such as 370,951, 3,523,022, and 3,769,020 can be used.

  Examples of water-dispersible vinyl polymers that can be used as matting agents include polymethyl acrylate, polymethyl methacrylate, polyacrylonitrile, acrylonitrile-α-methylstyrene copolymer, polystyrene, styrene-divinylbenzene copolymer Coalescence, polyvinyl acetate, polyethylene carbonate, polytetrafluoroethylene, etc., cellulose derivatives such as methyl cellulose, cellulose acetate, cellulose acetate propionate, etc. starch derivatives such as carboxy starch, carboxynitrophenyl starch, urea-formaldehyde-starch reaction It is preferable to use gelatin hardened with a known hardener and hardened gelatin made into a microcapsule hollow particle by coacervate hardening. That.

  As examples of the inorganic compound, silicon dioxide, titanium dioxide, magnesium dioxide, aluminum oxide, barium sulfate, calcium carbonate, silver chloride desensitized by a known method, silver bromide, glass, diatomaceous earth, and the like can be preferably used. Different types of substances can be mixed and used in the matting agent as necessary.

  The diameter of the matting agent is 30% or more of the film thickness of the image forming layer. When the image forming layer is composed of two or more layers, it means the total film thickness obtained by adding up all the image forming layers. In the present invention, since the image forming layer is 5 μm or more and 12 μm or less, the diameter of the matting agent is 0.15 μm or more. Preferably, the diameter of the matting agent is 30% or more and 120% or less of the film thickness of the image forming layer, more preferably 30% or more and 100% or less, and still more preferably 30% or more and 80% or less. As described above, by using particles having a large diameter as a matting agent, it is possible to prevent deterioration of transportability and adhesion of sensitive materials due to sinking of the matting agent into the film during heat development and external pressure. Became possible. In the present invention, the diameter of the matting agent means a value measured from a transmission electron microscope image.

  You may use together the mat agent which has such a diameter, and the mat agent from which a particle size differs. In this case, the matting agent having a diameter of 30% or more of the film thickness of the image forming layer is preferably 30% by mass or more, more preferably 30% by mass or more and 99% by mass or less of the entire matting agent, More preferably, it is 50 mass% or more and 95 mass% or less.

Further, the particle size distribution of the matting agent may be narrow or wide. The variation coefficient of the size distribution is preferably 50% or less, more preferably 40% or less, and still more preferably 30% or less. Here, the coefficient of variation is a value represented by (standard deviation of particle size) / (average value of particle size) × 100. It is also preferable to use two types of matting agents having a small variation coefficient and having an average particle size ratio larger than 3.
Since the matting agent greatly affects the haze and surface gloss of the coating film, it is preferable that the particle size, shape, and particle size distribution are brought into a state as necessary during the preparation of the matting agent or by mixing a plurality of matting agents.

Examples of matting agents preferably used in the present invention are shown below, but the present invention is not limited to the following compounds.
・ M-1: Polyethylene particles, specific gravity 0.90 (Flow Beads LE-1080, manufactured by Sumitomo Seika Co., Ltd.)
M-2: Polyethylene particle specific gravity 0.93 (Flow Beads EA-209, manufactured by Sumitomo Seika Co., Ltd.)
-M-3: Polyethylene particle specific gravity 0.96 (flow beads HE-3040 manufactured by Sumitomo Seika Co., Ltd.)
-M-4: Silicone particle specific gravity 0.97M-5 Silicone particle specific gravity 1.00 (E701 made by Toray Dow Silicone Co., Ltd.)
M-6: Silicone particle specific gravity 1.03M-7 polystyrene particle specific gravity 1.05 (SB-6 Sekisui Plastics Co., Ltd.)
M-8: Poly (St / MAA = 97/3) copolymer particle specific gravity 1.05
M-9: Poly (St / MAA = 90/10) copolymer particle specific gravity 1.06
M-10: Poly (St / MMA / MAA = 50/40/10) copolymer particles Specific gravity 1.09M-11 Cross-linked polyethylene particles Specific gravity 0.92
M-12: Cross-linked polyethylene particles, specific gravity 0.95
M-13: Cross-linked polyethylene particles, specific gravity 0.98
M-14: Cross-linked silicone particles, specific gravity 0.99
M-15: Cross-linked silicone particles, specific gravity 1.02
M-16: Cross-linked silicone particle specific gravity 1.04
M-17: Poly (St / DVB = 90/10) particles Specific gravity 1.06 (SX-713, manufactured by Soken Chemical Co., Ltd.)
M-18: Poly (St / DVB = 80/20) particle specific gravity 1.06 (SX-713, manufactured by Soken Chemical Co., Ltd.)
M-19: Poly (St / DVB = 70/30) particle specific gravity 1.07 (SX-713, manufactured by Soken Chemical Co., Ltd.)
M-20: Poly (St / MAA / DVB = 87/3/10) copolymer particle specific gravity 1.06 (SX-713α, manufactured by Soken Chemical Co., Ltd.)
M-21: Poly (St / MAA / DVB = 80/10/10) copolymer particle specific gravity 1.07 (SX-713α, manufactured by Soken Chemical Co., Ltd.)
M-22: Poly (St / MMA / MAA / DVB = 40/40/10/10) copolymer particle specific gravity 1.10

In the present invention, the matting agent may be contained in any layer as long as it is any layer on the surface side having the image forming layer with respect to the support (hereinafter sometimes referred to as an image forming layer surface). Preferably, it is contained in the outermost layer on the surface of the image forming layer, the layer functioning as the outermost surface layer, or the layer close to the outer surface, and is preferably contained in a layer acting as a so-called protective layer. More preferably, the matting agent is contained in the outermost layer and the layer adjacent to the outermost layer, and more preferably, the matting agent is contained in the outermost layer. The layer containing the matting agent may be a single layer or a plurality of layers.
When the image forming layer is provided on both sides of the support, the matting agent is contained on both sides.
In addition, even when the image forming layer is provided on one side of the support, a matting agent can be added to the back surface on the opposite side. In this case, the diameter of the matting agent is determined by the image forming layer. It is not necessary to be 30% or more of the film thickness. The volume weighted average of sphere equivalent diameters of the matting agent used for the back surface is preferably 1 μm or more and 15 μm or less, and more preferably 3 μm or more and 10 μm or less. The variation coefficient of the size distribution of the matting agent is preferably 3% or more and 50% or less, and more preferably 5% or more and 30% or less. Further, two or more types of matting agents having different average particle sizes can be used as the matting agent for the back surface. In this case, the difference in particle size between the matting agent having the largest average particle size and the smallest matting agent is preferably 2 μm or more and 14 μm or less, and more preferably 2 μm or more and 9 μm or less.

The content of the matting agent is within a range where the desired effect of the present invention is exhibited and the original function of the layer containing the matting agent is not excessively inhibited. The matting agent is preferably 1 mg / m ² or more and 400 mg / m ² or less, more preferably 20 mg / m ² or more and 250 mg / m ² or less when expressed in terms of the coating amount per 1 m ² of the photosensitive material.
When the matting agent is contained on the image forming layer surface side, the Beck smoothness is preferably about 30 seconds to 10,000 seconds, more preferably about 50 seconds to 1,000 seconds. When the matting agent is contained on the back surface side, it is preferable that the Beck smoothness is 2000 seconds or less and 10 seconds or more, and more preferably 1500 seconds or less and 50 seconds or more. In addition, the Beck smoothness in this specification is calculated | required from JISP8119 and TAPPI T479.

The coating liquid for forming the layer containing the matting agent may be prepared in any way, but in order to improve the dispersibility of the matting agent, the matting agent is dispersed in advance with a binder, and the matting agent particle dispersion It is preferable to be used as
The dispersion method is as follows: (a) a polymer to be a matting agent is dissolved in an aqueous medium (for example, dissolved in a low-boiling organic solvent), and dispersed in an aqueous medium to obtain polymer droplets. A method of preparing a dispersion of a matting agent by removing a solvent, (b) preparing fine particles such as a polymer to be a matting agent in advance, and removing the dispersion so as not to cause lumps in an aqueous medium. There are two methods of preparation. In the present invention, in consideration of the environment, the method (b) in which a low-boiling organic solvent is not discharged to the environment is preferable.

In the method of dispersing the matting agent, an aqueous medium containing a water-soluble polymer not derived from animal protein is previously present as a dispersion aid in an aqueous solvent, and known high-speed stirring means (for example, a disperser emulsifier, a homogenizer) The mixture can be mechanically dispersed using a mixer, turbine mixer, homogenizer) or ultrasonic emulsifier. In dispersing, in order to suppress foaming, means for dispersing in a reduced pressure state rather than atmospheric pressure can be used in combination. The dispersion aid to be used is generally dissolved in an aqueous medium in advance, and then the matting agent is generally added, but the matting agent remains in an aqueous dispersion obtained by polymerization (drying step). (Without going through). The dispersion aid can also be added to the dispersion during dispersion. Moreover, it can also add to a dispersion liquid for stabilization of the physical property after dispersion | distribution. In either case, it is common that a solvent (for example, water / alcohol) coexists. You may control pH by a suitable pH adjuster before and during dispersion or during dispersion.
In addition to the mechanical dispersion means, the stability of the dispersed matting agent may be increased by controlling the pH. In addition, a very small amount of a low-boiling organic solvent may be used for dispersion, and the organic solvent is usually removed after the formation of fine particles.

The prepared dispersion is stored with stirring for the purpose of suppressing the settling of the matting agent during storage, or stored in a highly viscous state (for example, using gelatin to make a jelly state) with a hydrophilic colloid. You can also Moreover, it is preferable to add a preservative for the purpose of preventing the propagation of various germs during storage.
The binder to be used is not particularly limited, but the same type of binder as that contained in the layer containing the matting agent is used. For example, when a matting agent is added to the outermost layer, gelatin is preferable as the binder, but it is also preferable to use polyvinyl alcohol (PVA) or a combination thereof. As gelatin, inert gelatin (for example, Nitta gelatin 750), phthalated gelatin (for example, Nitta gelatin 801), and the like can be used. Examples of PVA include those described in paragraph Nos. 0009 to 0020 of JP-A No. 2000-171936. Completely saponified PVA-105, partially saponified PVA-205, PVA-335, and modified polyvinyl alcohol MP- Preferred is 203 (trade name, manufactured by Kuraray Co., Ltd.).
Moreover, it is preferable to add and disperse | distribute a binder so that it may become 5 to 300 mass% with respect to a mat agent. More preferably, it adds so that it may become 10 mass% or more and 200 mass% or less.

Since the dispersion state of the mat particle dispersion in the present invention is stabilized when it contains a surfactant, it is preferable to add a surfactant. The surfactant used here is not particularly limited, but known ones can be used. Dispersing aids that have been disclosed in the past include alkylphenoxyethoxyethane sulfonate, polyoxyethylene alkylphenyl ether sulfonate, alkylbenzene sulfonate, alkyl naphthalene sulfonate, alkyl sulfate ester salt, alkyl sulfosuccinate Sodium oleyl methyl tauride, formaldehyde condensation polymer of naphthalene sulfonic acid, polyacrylic acid, polymethacrylic acid, maleic acid acrylic acid copolymer, carboxymethyl cellulose, cellulose sulfate and other anionic dispersants, polyoxyethylene alkyl ether, Nonionic dispersants such as sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyalkylene oxide block polymers, cationic dispersants and betaines Powders and the like. In particular, anionic surfactants such as sodium triisopropylnaphthalene sulfonate (a mixture of three different isopropyl group substitution positions) are preferred.
As a preservative that can be added to the dispersion, for example, benzoisothiazolinone sodium salt and parahydroxybenzoic acid esters (methyl ester, butyl ester, etc.) can be contained. The addition amount is preferably in the range of 0.005% by mass to 0.1% by mass with respect to the dispersion liquid.

(Description of organic silver salt)
1) Composition The organic silver salt that can be used in the present invention is relatively stable to light, but is heated to 80 ° C. or higher in the presence of exposed photosensitive silver halide and a reducing agent. In this case, the silver salt functions as a silver ion supplier to form a silver image. The organic silver salt may be any organic substance that can supply silver ions that can be reduced by a reducing agent. As for such non-photosensitive organic silver salt, paragraph numbers 0048 to 0049 of JP-A-10-62899, page 18 line 24 to page 19 line 37 of European Patent Publication No. 0803764A1, European Patent Publication. No. 0968212A1, JP-A-11-349591, JP-A-2000-7683, JP-A-2000-72711, and the like. Silver salts of organic acids, particularly silver salts of long-chain aliphatic carboxylic acids (having 10 to 30, preferably 15 to 28 carbon atoms) are preferred. Preferable examples of the fatty acid silver salt include silver lignocerate, silver behenate, silver arachidate, silver stearate, silver oleate, silver laurate, silver caproate, silver myristate, silver palmitate, silver erucate and the like. Including a mixture of In the present invention, among these fatty acid silvers, the silver behenate content is preferably 50 mol% to 100 mol%, more preferably 85 mol% to 100 mol%, still more preferably 95 mol% to 100 mol%. The following fatty acid silver is preferably used. Furthermore, it is preferable to use fatty acid silver having a silver erucate content of 2 mol% or less, more preferably 1 mol% or less, and still more preferably 0.1 mol% or less.

  Moreover, it is preferable that silver stearate content rate is 1 mol% or less. By making the stearic acid content 1 mol% or less, a silver salt of an organic acid having a low Dmin, high sensitivity and excellent image storage stability can be obtained. As said stearic acid content rate, 0.5 mol% or less is preferable and it is especially preferable not to contain substantially.

  Furthermore, when silver arachidate is included as the silver salt of the organic acid, the silver arachidate content is 6 mol% or less to obtain a low Dmin and an organic acid silver salt excellent in image storability. It is preferable at a point and it is still more preferable that it is 3 mol% or less.

2) Shape The shape of the organic silver salt that can be used in the present invention is not particularly limited, and may be any of a needle shape, a rod shape, a flat plate shape, and a flake shape.
In the present invention, scaly organic silver salts are preferred. In addition, short needle-like, rectangular parallelepiped, cubic or potato-like amorphous particles having a major axis / uniaxial length ratio of less than 5 are also preferably used. These organic silver particles have a feature that there is less fog at the time of thermal development than long needle-like particles having a ratio of the major axis to the uniaxial length of 5 or more. In particular, particles having a major axis / uniaxial ratio of 3 or less are preferable because the mechanical stability of the coating film is improved. In the present specification, the scaly organic silver salt is defined as follows. The organic acid silver salt was observed with an electron microscope, the shape of the organic acid silver salt particle was approximated to a rectangular parallelepiped, and the sides of the rectangular parallelepiped were designated as a, b, and c from the shortest side (c was the same as b). Then, the shorter numerical values a and b are calculated, and x is obtained as follows.
x = b / a

  In this way, x is obtained for about 200 particles, and when the average value x (average) is obtained, particles satisfying the relationship of x (average) ≧ 1.5 are defined as flakes. Preferably, 30 ≧ x (average) ≧ 1.5, more preferably 15 ≧ x (average) ≧ 1.5. Incidentally, the needle shape is 1 ≦ x (average) <1.5.

  In the flake shaped particle, a can be regarded as a thickness of a tabular particle having a main plane with b and c as sides. The average of a is preferably 0.01 μm or more and 0.3 μm or less, and more preferably 0.1 μm or more and 0.23 μm or less. The average c / b is preferably 1 or more and 9 or less, more preferably 1 or more and 6 or less, still more preferably 1 or more and 4 or less, and most preferably 1 or more and 3 or less.

By setting the equivalent sphere diameter to 0.05 μm or more and 1 μm or less, aggregation is hardly caused in the photosensitive material, and image storability is improved. The sphere equivalent diameter is preferably 0.1 μm or more and 1 μm or less. In the present invention, the method for measuring the equivalent sphere diameter is obtained by directly photographing a sample using an electron microscope and then image-processing the negative.
In the flake shaped particles, the spherical equivalent diameter / a of the particles is defined as the aspect ratio. The aspect ratio of the flake shaped particles is preferably 1.1 or more and 30 or less, more preferably 1.1 or more and 15 or less, from the viewpoint of preventing aggregation in the photosensitive material and improving the image storage stability. .

  The particle size distribution of the organic silver salt is preferably monodispersed. Monodispersion is preferably 100% or less, more preferably 80% or less, and even more preferably 50% of the value obtained by dividing the standard deviation of the lengths of the short and long axes by the short and long axes. It is as follows. The method for measuring the shape of the organic silver salt can be determined from a transmission electron microscope image of the organic silver salt dispersion. As another method for measuring monodispersity, there is a method for obtaining the standard deviation of the volume weighted average diameter of the organic silver salt, and the percentage (variation coefficient) of the value divided by the volume weighted average diameter is preferably 100% or less, more Preferably it is 80% or less, More preferably, it is 50% or less. As a measuring method, for example, it is obtained from the particle size (volume weighted average diameter) obtained by irradiating an organic silver salt dispersed in a liquid with laser light and obtaining an autocorrelation function with respect to the temporal change of the fluctuation of the scattered light. Can do.

3) Preparation Known methods and the like can be applied to the production and dispersion method of organic acid silver used in the present invention. For example, the above-mentioned JP-A-10-62899, European Patent Publication No. 0803763A1, European Patent Publication No. 0968212A1, JP-A-11-349591, JP-A-2000-7683, JP-A-2000-72711, JP-A-2001-163889, 2001-163890, 2001-163825, 2001-33907, 2001-188313, 2001-83651, 2002-6442, 2002-49117, 2002-31870, 2002-107868 You can refer to the issue.

  In addition, when the photosensitive silver salt is allowed to coexist at the time of dispersion of the organic silver salt, the fog is increased and the sensitivity is remarkably reduced. Therefore, it is more preferable that the photosensitive silver salt is not substantially contained at the time of dispersion. In the present invention, the amount of the photosensitive silver salt in the aqueous dispersion to be dispersed is preferably 1 mol% or less, more preferably 0.1 mol% or less with respect to 1 mol of the organic acid silver salt in the liquid. Further, it is more preferable that no positive photosensitive silver salt is added.

  In the present invention, it is possible to produce a photosensitive material by mixing an organic silver salt aqueous dispersion and a photosensitive silver salt aqueous dispersion, but 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 mol% to 30 mol%, more preferably 2 mol% to 20 mol%, particularly preferably 3 mol% to 15 mol%. Mixing two or more organic silver salt water dispersions and two or more photosensitive silver salt water dispersions when mixing is a method preferably used for adjusting photographic properties.

4) Addition amount Although the organic silver salt in the present invention can be used in a desired amount, the total amount of coated silver including silver halide is preferably 0.1 g / m ² or more and 5.0 g / m ² or less, more preferably. It is 0.3 g / m ² or more and 3.0 g / m ² or less, more preferably 0.5 g / m ² or more and 2.0 g / m ² or less. In particular, in order to improve image storability, the total coated silver amount is preferably 1.8 g / m ² or less, more preferably 1.6 g / m ² or less. If the preferred reducing agent in the present invention is used, a sufficient image density can be obtained even with such a low silver amount.

(Description of reducing agent)
The photothermographic material of the present invention preferably contains a heat developer which is a reducing agent for the organic silver salt. The reducing agent for the organic silver salt may be any substance (preferably an organic substance) that reduces silver ions to metallic silver. Examples of such reducing agents are described in JP-A No. 11-65021, paragraphs 0043 to 0045, and European Patent Publication No. 0803764A1, page 7, line 34 to page 18, line 12.
In the present invention, the reducing agent is preferably a so-called hindered phenol-based reducing agent or bisphenol-based reducing agent having a substituent at the ortho position of the phenolic hydroxyl group, and more preferably a compound represented by the following general formula (R).
General formula (R)

In the general formula (R), R ¹¹ and R ¹¹ ′ each independently represents an alkyl group having 1 to 20 carbon atoms. R ¹² and R ¹² ′ each independently represent a hydrogen atom or a substituent that can be substituted on a benzene ring. L represents a —S— group or a —CHR ¹³ — group. R ¹³ represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms. X ¹ and X ¹ ′ each independently represent a hydrogen atom or a group capable of substituting for a benzene ring.

The general formula (R) will be described in detail.
In the following, when referred to as an alkyl group, a cycloalkyl group is also included in this unless otherwise specified.
1) R ¹¹ and R ¹¹ '
R ¹¹ and R ¹¹ ′ are each independently a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms. The substituent of the alkyl group is not particularly limited, but preferably an aryl group, a hydroxy group, an alkoxy group, an aryloxy group, an alkylthio group, an arylthio group, an acylamino group, a sulfonamido group, a sulfonyl group, a phosphoryl group, Examples thereof include an acyl group, a carbamoyl group, an ester group, a ureido group, a urethane group, and a halogen atom.

2) R ¹² and R ¹² ', X ¹ and X ¹ '
R ¹² and R ¹² ′ each independently represent a hydrogen atom or a substituent capable of substituting for a benzene ring, and X ¹ and X ¹ ′ each independently represent a hydrogen atom or a group capable of substituting for a benzene ring. Preferred examples of each group that can be substituted on the benzene ring include an alkyl group, an aryl group, a halogen atom, an alkoxy group, and an acylamino group.

3) L
L represents a —S— group or a —CHR ¹³ — group. R ¹³ represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, and the alkyl group may have a substituent. Specific examples of the unsubstituted alkyl group for R ¹³ are methyl group, ethyl group, propyl group, butyl group, heptyl group, undecyl group, isopropyl group, 1-ethylpentyl group, 2,4,4-trimethylpentyl group, cyclohexyl group. Group, 2,4-dimethyl-3-cyclohexenyl group, 2,4-dimethyl-3-cyclohexenyl group and the like. Examples of the substituent of the alkyl group are the same as the substituent of R ¹¹ , and are a halogen atom, alkoxy group, alkylthio group, aryloxy group, arylthio group, acylamino group, sulfonamido group, sulfonyl group, phosphoryl group, oxycarbonyl group, Examples thereof include a carbamoyl group and a sulfamoyl group.

4) Preferred substituents R ¹¹ and R ¹¹ ′ are preferably a primary, secondary or tertiary alkyl group having 1 to 15 carbon atoms, specifically a methyl group, an isopropyl group, a t-butyl group, Examples thereof include a t-amyl group, a t-octyl group, a cyclohexyl group, a cyclopentyl group, a 1-methylcyclohexyl group, and a 1-methylcyclopropyl group. R ¹¹ and R ¹¹ ′ are more preferably an alkyl group having 1 to 4 carbon atoms, and among them, a methyl group, a t-butyl group, a t-amyl group, and a 1-methylcyclohexyl group are more preferable, and a methyl group and a t-butyl group are preferable. Groups are most preferred.

R ¹² and R ¹² ′ are preferably an alkyl group having 1 to 20 carbon atoms, specifically a methyl group, an ethyl group, a propyl group, a butyl group, an isopropyl group, a t-butyl group, a t-amyl group, Examples thereof include a cyclohexyl group, a 1-methylcyclohexyl group, a benzyl group, a methoxymethyl group, and a methoxyethyl group. More preferred are methyl group, ethyl group, propyl group, isopropyl group and t-butyl group, and particularly preferred are methyl group and ethyl group.
X ¹ and X ¹ ′ are preferably a hydrogen atom, a halogen atom, or an alkyl group, and more preferably a hydrogen atom.

L is preferably a —CHR ¹³ — group.
R ¹³ is preferably a hydrogen atom or an alkyl group having 1 to 15 carbon atoms. As the alkyl group, a cyclic alkyl group is also preferably used in addition to a chain alkyl group. Moreover, what has a C = C bond in these alkyl groups can also be used preferably. Examples of the alkyl group include methyl group, ethyl group, propyl group, isopropyl group, 2,4,4-trimethylpentyl group, cyclohexyl group, 2,4-dimethyl-3-cyclohexenyl group, 3,5-dimethyl-3- A cyclohexenyl group and the like are preferable. R ¹³ is particularly preferably a hydrogen atom, a methyl group, an ethyl group, a propyl group, an isopropyl group, or a 2,4-dimethyl-3-cyclohexenyl group.

When R ¹¹ and R ¹¹ ′ are tertiary alkyl groups and R ¹² and R ¹² ′ are methyl groups, R ¹³ is a primary or secondary alkyl group having 1 to 8 carbon atoms (methyl group, ethyl group, propyl group). Group, isopropyl group, 2,4-dimethyl-3-cyclohexenyl group and the like).
When R ¹¹ and R ¹¹ ′ are tertiary alkyl groups and R ¹² and R ¹² ′ are alkyl groups other than methyl groups, R ¹³ is preferably a hydrogen atom.
When R ¹¹ and R ¹¹ ′ are not a tertiary alkyl group, R ¹³ is preferably a hydrogen atom or a secondary alkyl group, and particularly preferably a secondary alkyl group. Preferred groups as the secondary alkyl group for R ¹³ are isopropyl group and 2,4-dimethyl-3-cyclohexenyl group.
The reducing agent has different heat developability and developed silver tone depending on the combination of R ¹¹ , R ¹¹ ′, R ¹² , R ¹² ′ and R ¹³ . Since these can be adjusted by combining two or more kinds of reducing agents, it is preferable to use two or more kinds in combination depending on the purpose.

  Although the specific example of the reducing agent in this invention including the compound represented by general formula (R) below is shown, this invention is not limited to these.

Examples of preferable reducing agents in the present invention other than those described above are compounds described in JP-A Nos. 2001-188314, 2001-209145, 2001-350235, 2002-156727, and EP1278101A2.
In the present invention, the addition amount of the reducing agent is preferably 0.1 g / m ² or more and 3.0 g / m ² or less, more preferably 0.2 g / m ² or more and 2.0 g / m ² or less, and still more preferably. Is 0.3 g / m ² or more and 1.0 g / m ² or less. 5 mol% or more and 50 mol% or less is preferably contained with respect to 1 mol of silver on the surface having the image forming layer, more preferably 8 mol% or more and 30 mol% or less, and 10 mol% or more and 20 mol% or less. More preferably, it is contained. The reducing agent is preferably contained in the image forming layer.

The reducing agent may be contained in the coating solution by any method such as a solution form, an emulsified dispersion form, or a solid fine particle dispersion form, and may be contained in the photosensitive material.
Well-known emulsification and dispersion methods include oils such as dibutyl phthalate, tricresyl phosphate, dioctyl sebacate or tri (2-ethylhexyl) phosphate, and an auxiliary solvent such as ethyl acetate and cyclohexanone, and dodecylbenzene. Examples thereof include a method of mechanically preparing an emulsified dispersion by adding a surfactant such as sodium sulfonate, oleoyl-N-methyl taurate, sodium di (2-ethylhexyl) sulfosuccinate. At this time, it is also preferable to add a polymer such as α-methylstyrene oligomer or poly (t-butylacrylamide) for the purpose of adjusting the viscosity and refractive index of the oil droplets.

In addition, as a solid fine particle dispersion method, a reducing agent powder is dispersed in an appropriate solvent such as water by a ball mill, a colloid mill, a vibration ball mill, a sand mill, a jet mill, a roller mill, or an ultrasonic wave to produce a solid dispersion. A method is mentioned. In this case, a protective colloid (for example, polyvinyl alcohol) or a surfactant (for example, an anionic surfactant such as sodium triisopropylnaphthalenesulfonate (a mixture of three isopropyl groups having different substitution positions)) may be used. Good. In the mills, beads such as zirconia are usually used as a dispersion medium, and Zr and the like eluted from these beads may be mixed in the dispersion. Although it depends on the dispersion conditions, it is usually in the range of 1 ppm to 1000 ppm. If the Zr content in the light-sensitive material is 0.5 mg or less per 1 g of silver, there is no practical problem.
The aqueous dispersion preferably contains a preservative (for example, benzoisothiazolinone sodium salt).
Particularly preferred is a solid particle dispersion method of a reducing agent, in which fine particles having an average particle size of 0.01 μm to 10 μm, preferably 0.05 μm to 5 μm, more preferably 0.1 μm to 2 μm are added. Is preferred. In the present application, it is preferable to use other solid dispersions dispersed in a particle size within this range.

(Description of development accelerator)
In the photothermographic material of the present invention, a sulfonamide phenol compound represented by the general formula (A) described in JP-A-2000-267222, JP-A-2000-330234, or the like as a development accelerator, Hindered phenol compounds represented by general formula (II) described in JP-A No. 2001-92075, general formula (I) described in JP-A No. 10-62895, JP-A No. 11-15116 and the like, A hydrazine-based compound represented by general formula (D) of JP-A No. 2002-156727 or general formula (1) described in JP-A No. 2002-278017, and described in JP-A No. 2001-264929 Phenol-based or naphthol-based compounds represented by the general formula (2) are preferably used. Moreover, the phenol type compound described in Unexamined-Japanese-Patent No. 2002-311533 and Unexamined-Japanese-Patent No. 2002-341484 is also preferable. In particular, naphthol compounds described in JP-A No. 2003-66558 are preferable. These development accelerators are used in the range of 0.1 mol% or more and 20 mol% or less, preferably 0.5 mol% or more and 10 mol% or less, more preferably 1 mol% or more with respect to the reducing agent. The range is 5 mol% or less. The introduction method to the light-sensitive material includes the same method as the reducing agent, but it is particularly preferable to add as a solid dispersion or an emulsified dispersion. When added as an emulsified dispersion, it is added as an emulsified dispersion dispersed using a high-boiling solvent that is solid at room temperature and a low-boiling auxiliary solvent, or as a so-called oilless emulsified dispersion that does not use a high-boiling solvent. It is preferable to add.
In the present invention, among the above development accelerators, hydrazine compounds described in JP-A Nos. 2002-156727 and 2002-278017 and naphthol compounds described in JP-A No. 2003-66558 are used. Is more preferable.

Particularly preferred development accelerators in the invention are compounds represented by the following general formulas (A-1) and (A-2).
Formula (A-1)
Q ₁ -NHNH-Q ₂
(Wherein Q ₁ represents an aromatic group or a heterocyclic group bonded to —NHNH—Q ₂ at a carbon atom, and Q ₂ represents a carbamoyl group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a sulfonyl group, Or represents a sulfamoyl group.)

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

  These rings may have a substituent, and when they have two or more substituents, these substituents may be the same or different. Examples of substituents include halogen atoms, alkyl groups, aryl groups, carbonamido groups, alkylsulfonamido groups, arylsulfonamido groups, alkoxy groups, aryloxy groups, alkylthio groups, arylthio groups, carbamoyl groups, sulfamoyl groups, cyano Groups, alkylsulfonyl groups, arylsulfonyl groups, alkoxycarbonyl groups, aryloxycarbonyl groups, and acyl groups. When these substituents are substitutable groups, they may further have substituents. Examples of preferred substituents include halogen atoms, alkyl groups, aryl groups, carbonamido groups, alkylsulfonamido groups, aryls. Sulfonamide group, alkoxy group, aryloxy group, alkylthio group, arylthio group, acyl group, alkoxycarbonyl group, aryloxycarbonyl group, carbamoyl group, cyano group, sulfamoyl group, alkylsulfonyl group, arylsulfonyl group, and acyloxy group Can be mentioned.

The carbamoyl group represented by Q ₂ is preferably a carbamoyl group having 1 to 50 carbon atoms, more preferably 6 to 40 carbon atoms. For example, unsubstituted carbamoyl, methylcarbamoyl, N-ethylcarbamoyl, N-propylcarbamoyl N-sec-butylcarbamoyl, N-octylcarbamoyl, N-cyclohexylcarbamoyl, N-tert-butylcarbamoyl, N-dodecylcarbamoyl, N- (3-dodecyloxypropyl) carbamoyl, N-octadecylcarbamoyl, N- {3 -(2,4-tert-pentylphenoxy) propyl} carbamoyl, N- (2-hexyldecyl) carbamoyl, N-phenylcarbamoyl, N- (4-dodecyloxyphenyl) carbamoyl, N- (2-chloro-5 Dodecyloxycarbo Butylphenyl) carbamoyl, N- naphthylcarbamoyl, N-3- pyridylcarbamoyl include N- benzylcarbamoyl.

The acyl group represented by Q ₂ is preferably an acyl group having 1 to 50 carbon atoms, more preferably 6 to 40 carbon atoms, such as formyl, acetyl, 2-methylpropanoyl, cyclohexylcarbonyl, octanoyl, 2 -Hexyldecanoyl, dodecanoyl, chloroacetyl, trifluoroacetyl, benzoyl, 4-dodecyloxybenzoyl, 2-hydroxymethylbenzoyl. The alkoxycarbonyl group represented by Q2 is preferably an alkoxycarbonyl group having 2 to 50 carbon atoms, more preferably 6 to 40 carbon atoms, such as methoxycarbonyl, ethoxycarbonyl, isobutyloxycarbonyl, cyclohexyloxycarbonyl, dodecyl. Examples include oxycarbonyl and benzyloxycarbonyl.

The aryloxycarbonyl group represented by Q ₂ is preferably an aryloxycarbonyl group having 7 to 50 carbon atoms, more preferably 7 to 40 carbon atoms, such as phenoxycarbonyl, 4-octyloxyphenoxycarbonyl, 2-hydroxy Examples thereof include methylphenoxycarbonyl and 4-dodecyloxyphenoxycarbonyl. The sulfonyl group represented by Q2 is preferably a sulfonyl group having 1 to 50 carbon atoms, more preferably 6 to 40 carbon atoms, such as methylsulfonyl, butylsulfonyl, octylsulfonyl, 2-hexadecylsulfonyl, 3-dodecyl. Examples include oxypropylsulfonyl, 2-octyloxy-5-tert-octylphenylsulfonyl, and 4-dodecyloxyphenylsulfonyl.

The sulfamoyl group represented by Q ₂ is preferably a sulfamoyl group having 0 to 50 carbon atoms, more preferably 6 to 40 carbon atoms, such as an unsubstituted sulfamoyl group, an N-ethylsulfamoyl group, N- (2- Ethylhexyl) sulfamoyl, N-decylsulfamoyl, N-hexadecylsulfamoyl, N- {3- (2-ethylhexyloxy) propyl} sulfamoyl, N- (2-chloro-5-dodecyloxycarbonylphenyl) sulfamoyl, N- (2-tetradecyloxyphenyl) sulfamoyl is mentioned. The group represented by Q ₂ may further have the group exemplified as the substituent of the 5- to 7-membered unsaturated ring represented by Q ₁ at a substitutable position. When it has two or more substituents, these substituents may be the same or different.

Next, a preferable range of the compound represented by formula (A-1) is described. Q ₁ is preferably a 5- to 6-membered unsaturated ring, such as a benzene ring, pyrimidine ring, 1,2,3-triazole ring, 1,2,4-triazole ring, tetrazole ring, 1,3,4-thiadiazole ring. 1,2,4-thiadiazole ring, 1,3,4-oxadiazole ring, 1,2,4-oxadiazole ring, thiazole ring, oxazole ring, isothiazole ring, isoxazole ring, and these rings Is more preferably a ring fused with a benzene ring or an unsaturated heterocycle. Q ₂ is preferably a carbamoyl group, particularly preferably a carbamoyl group having a hydrogen atom on a nitrogen atom.

Formula (A-2)

In the general formula (A-2), R ₁ represents an alkyl group, an acyl group, an acylamino group, a sulfonamide group, an alkoxycarbonyl group, or a carbamoyl group. R ₂ represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an aryloxy group, an alkylthio group, an arylthio group, an acyloxy group, or a carbonate group. R ₃ and R ₄ each represents a group that can be substituted on the benzene ring mentioned in the example of the substituent of formula (A-1). R ₃ and R ₄ may be connected to each other to form a condensed ring.
R ₁ is preferably an alkyl group having 1 to 20 carbon atoms (eg, methyl group, ethyl group, isopropyl group, butyl group, tert-octyl group, cyclohexyl group, etc.), acylamino group (eg, acetylamino group, benzoylamino group, methyl group). Ureido group, 4-cyanophenylureido group, etc.), carbamoyl group (n-butylcarbamoyl group, N, N-diethylcarbamoyl group, phenylcarbamoyl group, 2-chlorophenylcarbamoyl group, 2,4-dichlorophenylcarbamoyl group, etc.) acylamino Groups (including ureido groups and urethane groups) are more preferred. R2 is preferably a halogen atom (more preferably a chlorine atom or a bromine atom), an alkoxy group (for example, methoxy group, butoxy group, n-hexyloxy group, n-decyloxy group, cyclohexyloxy group, benzyloxy group, etc.), aryloxy A group (phenoxy group, naphthoxy group, etc.).
R ₃ is preferably a hydrogen atom, a halogen atom, or an alkyl group having 1 to 20 carbon atoms, and most preferably a halogen atom. R ₄ is preferably a hydrogen atom, an alkyl group or an acylamino group, more preferably an alkyl group or an acylamino group. Examples of these preferable substituents are the same as those for R ₁ . When R ₄ is an acylamino group, R ₄ is preferably linked to R ₃ to form a carbostyryl ring.

In the general formula (A-2), when R ₃ and R ₄ are connected to each other to form a condensed ring, a naphthalene ring is particularly preferable as the condensed ring. The same substituent as the example of a substituent quoted by general formula (A-1) may couple | bond with the naphthalene ring. When general formula (A-2) is a naphthol-based compound, R ₁ is preferably a carbamoyl group. Of these, a benzoyl group is particularly preferable. R ₂ is preferably an alkoxy group or an aryloxy group, and particularly preferably an alkoxy group.

  Hereinafter, preferred specific examples of the development accelerator in the invention will be given. The present invention is not limited to these.

(Description of hydrogen bonding compound)
When the reducing agent in the present invention has an aromatic hydroxyl group (—OH) or amino group (—NHR, R is a hydrogen atom or an alkyl group), particularly in the case of the bisphenols described above, these groups and hydrogen bonds It is preferable to use together a non-reducing compound having a group capable of forming.
Examples of the group that forms a hydrogen bond with a hydroxyl group or an amino group include a phosphoryl group, a sulfoxide group, a sulfonyl group, a carbonyl group, an amide group, an ester group, a urethane group, a ureido group, a tertiary amino group, and a nitrogen-containing aromatic group. Can be mentioned. Among them, preferred are a phosphoryl group, a sulfoxide group, an amide group (however, it has no> N—H group and is blocked like> N—Ra (Ra is a substituent other than H)), a urethane group. (However, it has no> N—H group and is blocked like> N—Ra (Ra is a substituent other than H)), a ureido group (however, it has no> N—H group,> N-Ra (Ra is a substituent other than H).)
In the present invention, a particularly preferred hydrogen bonding compound is a compound represented by the following general formula (D).
Formula (D)

In the general formula (D), R ²¹ to R ²³ each independently represents an alkyl group, an aryl group, an alkoxy group, an aryloxy group, an amino group or a heterocyclic group, and these groups may be substituted even if they are unsubstituted. You may have.
When R ²¹ to R ²³ have a substituent, examples of the substituent include a halogen atom, an alkyl group, an aryl group, an alkoxy group, an amino group, an acyl group, an acylamino group, an alkylthio group, an arylthio group, a sulfonamide group, an acyloxy group, Examples thereof include an oxycarbonyl group, a carbamoyl group, a sulfamoyl group, a sulfonyl group, and a phosphoryl group. Preferred examples of the substituent include an alkyl group or an aryl group such as a methyl group, an ethyl group, an isopropyl group, a t-butyl group, and a t-octyl group. Group, phenyl group, 4-alkoxyphenyl group, 4-acyloxyphenyl group and the like.
Specific examples of the alkyl group represented by R ²¹ to R ²³ include a methyl group, an ethyl group, a butyl group, an octyl group, a dodecyl group, an isopropyl group, a t-butyl group, a t-amyl group, a t-octyl group, a cyclohexyl group, Examples include 1-methylcyclohexyl group, benzyl group, phenethyl group, 2-phenoxypropyl group and the like.
Examples of the aryl group include phenyl group, cresyl group, xylyl group, naphthyl group, 4-t-butylphenyl group, 4-t-octylphenyl group, 4-anisidyl group, and 3,5-dichlorophenyl group.
Alkoxy groups include methoxy, ethoxy, butoxy, octyloxy, 2-ethylhexyloxy, 3,5,5-trimethylhexyloxy, dodecyloxy, cyclohexyloxy, 4-methylcyclohexyloxy, benzyl An oxy group etc. are mentioned.
Examples of the aryloxy group include a phenoxy group, a cresyloxy group, an isopropylphenoxy group, a 4-t-butylphenoxy group, a naphthoxy group, and a biphenyloxy group.
Examples of the amino group include a dimethylamino group, a diethylamino group, a dibutylamino group, a dioctylamino group, an N-methyl-N-hexylamino group, a dicyclohexylamino group, a diphenylamino group, and an N-methyl-N-phenylamino group. .

R ²¹ to R ²³ are preferably an alkyl group, an aryl group, an alkoxy group, or an aryloxy group. In view of the effects of the present invention, at least one of R ²¹ to R ²³ is preferably an alkyl group or an aryl group, and more preferably two or more are an alkyl group or an aryl group. In addition, it is preferable that R ²¹ to R ²³ are the same group in that they can be obtained at low cost.
Specific examples of the hydrogen bonding compound including the compound of the general formula (D) in the present invention are shown below, but the present invention is not limited thereto.

Specific examples of the hydrogen bonding compound include those described in European Patent No. 1096310, JP-A No. 2002-156727, and JP-A No. 2002-318431 in addition to the above.
The compound represented by the general formula (D) in the present invention can be used in a light-sensitive material by being incorporated in a coating solution in the form of a solution, an emulsified dispersion, or a solid dispersion fine particle dispersion in the same manner as the reducing agent. It is preferable to use it as a product. These compounds form a hydrogen-bonding complex with a compound having a phenolic hydroxyl group or an amino group in a solution state, and depending on the combination of the reducing agent and the compound of the general formula (D) in the present invention, the compound may be crystallized as a complex. It can be isolated in the state.
The use of the crystal powder isolated in this way as a solid dispersed fine particle dispersion is particularly preferable for obtaining stable performance. Further, a method in which the reducing agent and the compound of the general formula (D) in the present invention are mixed in a powder and complexed at the time of dispersion with a sand grinder mill or the like using an appropriate dispersant can be preferably used.
The compound of the general formula (D) in the present invention is preferably used in the range of 1 mol% to 200 mol%, more preferably in the range of 10 mol% to 150 mol%, based on the reducing agent. More preferably, it is the range of 20 mol% or more and 100 mol%.

(Description of silver halide)
1) Halogen composition The photosensitive silver halide used in the present invention is not particularly limited as a halogen composition, and is silver chloride, silver chlorobromide, silver bromide, silver iodobromide, silver iodochlorobromide, silver iodide. Can be used. Of these, silver bromide, silver iodobromide and silver iodide are preferred. The distribution of the halogen composition in the grains may be uniform, the halogen composition may be changed stepwise, or may be continuously changed. Further, silver halide grains having a core / shell structure can be preferably used. A preferable structure is a 2- to 5-fold structure, more preferably 2- to 4-fold core / shell particles. A technique for localizing silver bromide or silver iodide on the surface of silver chloride, silver bromide or silver chlorobromide grains can also be preferably used.

2) Grain Forming Methods Methods for forming photosensitive silver halide are well known in the art and are described, for example, in Research Disclosure No. 17029, June 1978, and US Pat. No. 3,700,458. In particular, a photosensitive silver halide is prepared by adding a silver supply compound and a halogen supply compound into gelatin or another polymer solution, and then mixed with an organic silver salt. Use the method. Further, the method described in paragraph Nos. 0217 to 0224 of JP-A No. 11-119374, and the methods described in JP-A Nos. 11-352627 and 2000-347335 are also preferable.

3) Grain size The grain size of the photosensitive silver halide is preferably small for the purpose of keeping the cloudiness after image formation low, specifically 0.20 μm or less, more preferably 0.01 μm or more and 0.15 μm or less. More preferably, it is 0.02 μm or more and 0.12 μm or less. The grain size here means the diameter when converted into a circular image having the same area as the projected area of silver halide grains (in the case of tabular grains, the projected area of the main plane).

4) Grain shape Examples of the shape of the silver halide grains include cubes, octahedrons, tabular grains, spherical grains, rod-like grains, and potato grains. In the present invention, cubic grains are particularly preferred. Grains with rounded corners of silver halide grains can also be preferably used. The surface index (Miller index) on the outer surface of the photosensitive silver halide grain is not particularly limited, but the ratio of the {100} plane, which has high spectral sensitizing efficiency when adsorbed by the spectral sensitizing dye, is high. preferable. The ratio is preferably 50% or more, more preferably 65% or more, and still more preferably 80% or more. The ratio of the Miller index {100} plane is determined by T.sub. Tani; Imaging Sci. 29, 165 (1985).

5) Heavy Metal The photosensitive silver halide grain in the invention can contain a metal or metal complex of Group 8 to Group 10 of the Periodic Table (showing Groups 1 to 18). As the central metal of the group 8 to group 10 metal or metal complex of the periodic table, rhodium, ruthenium and iridium are preferable. One kind of these metal complexes may be used, or two or more kinds of complexes of the same metal and different metals may be used in combination. The preferred content is in the range of 1 × 10 ⁻⁹ mol to 1 × 10 ⁻³ mol with ^respect to 1 mol of silver. These heavy metals and metal complexes and methods for adding them are described in JP-A-7-225449, JP-A-11-65021, paragraphs 0018 to 0024, and JP-A-11-119374, paragraphs 0227 to 0240.

In the present invention, silver halide grains in which a hexacyano metal complex is present on the outermost surface of the grains are preferred. The hexacyano metal complexes include [Fe (CN) ₆ ] ⁴⁻ , [Fe (CN) ₆ ] ³⁻ , [Ru (CN) ₆ ] ⁴⁻ , [Os (CN) ₆ ] ⁴⁻ , [Co ( CN) ₆ ] ³⁻ , [Rh (CN) ₆ ] ³⁻ , [Ir (CN) ₆ ] ³⁻ , [Cr (CN) ₆ ] ³⁻ , [Re (CN) ₆ ] ^{3− and the} like. . In the present invention, a hexacyano Fe complex is preferred.

  The hexacyano metal complex is present in the form of ions in aqueous solution, so the counter cation is not important, but it is easy to mix with water and is suitable for precipitation of silver halide emulsions. Sodium ion, potassium ion, rubidium It is preferable to use alkali metal ions such as ions, cesium ions, and lithium ions, ammonium ions, and alkylammonium ions (for example, tetramethylammonium ions, tetraethylammonium ions, tetrapropylammonium ions, tetra (n-butyl) ammonium ions).

  In addition to water, the hexacyano metal complex is miscible with a mixed solvent or gelatin with an appropriate organic solvent miscible with water (for example, alcohols, ethers, glycols, ketones, esters, amides, etc.). Can be added.

The addition amount of the hexacyano metal complex is preferably 1 × 10 ⁻⁵ mol or more and 1 × 10 ⁻² mol or less, more preferably 1 × 10 ⁻⁴ mol or more and 1 × 10 ⁻³ mol or less per mol of silver.

  In order for the hexacyano metal complex to be present on the outermost surface of the silver halide grain, the chalcogen sensitization of sulfur sensitization, selenium sensitization and tellurium sensitization is completed after the addition of the aqueous silver nitrate solution used for grain formation. It is added directly before the completion of the preparation step before the chemical sensitization step for performing noble metal sensitization such as sensitization and gold sensitization, during the washing step, during the dispersion step, or before the chemical sensitization step. In order to prevent the silver halide fine grains from growing, it is preferable to add the hexacyano metal complex immediately after the grain formation, and it is preferable to add it before the completion of the preparation step.

  The addition of the hexacyano metal complex may be started after adding 96% by mass of the total amount of silver nitrate to be added to form grains, more preferably starting after adding 98% by mass, The addition of 99% by mass is particularly preferable.

  When these hexacyanometal complexes are added after the addition of the aqueous silver nitrate solution just before the completion of grain formation, they can be adsorbed on the outermost surface of the silver halide grains, and most of them form slightly soluble salts with silver ions on the grain surface. To do. Since this silver salt of hexacyanoiron (II) is less soluble than AgI, it is possible to prevent re-dissolution by fine particles and to produce silver halide fine particles having a small particle size. .

Further, regarding a metal atom (for example, [Fe (CN) ₆ ] ⁴⁻ ), a silver halide emulsion desalting method and a chemical sensitization method which can be contained in the silver halide grains used in the present invention, JP-A No. 11-101. No. 84574, paragraph numbers 0046 to 0050, JP-A No. 11-65021, paragraph numbers 0025 to 0031, and JP-A No. 11-119374, paragraph numbers 0242 to 0250.

6) Gelatin As the gelatin contained in the photosensitive silver halide emulsion used in the present invention, various gelatins can be used. It is necessary to maintain a good dispersion state of the photosensitive silver halide emulsion in the coating solution containing an organic silver salt, and gelatin having a molecular weight of 10,000 to 1,000,000 is preferably used. It is also preferable to phthalate the gelatin substituent. These gelatins may be used at the time of grain formation or at the time of dispersion after desalting, but are preferably used at the time of grain formation.

7) Sensitizing Dye Sensitizing dyes applicable to the present invention are those that can spectrally sensitize silver halide grains in a desired wavelength region when adsorbed on silver halide grains, and are suitable for the spectral characteristics of the exposure light source. Sensitizing dyes with sensitivity can be advantageously selected. Regarding the sensitizing dye and the addition method, paragraphs 0103 to 0109 of JP-A No. 11-65021, compounds represented by formula (II) of JP-A No. 10-186572, and formulas (I of JP-A No. 11-119374) ) And the dye described in Example 5 of U.S. Pat. Nos. 5,510,236 and 3,871,887, JP-A-2-96131, JP-A-59-48753. No. 19, page 38 to line 20, page 35 of European Patent Publication No. 0803764A1, JP 2001-272747, JP 2001-290238, JP 2002-23306, etc. It is described in. These sensitizing dyes may be used alone or in combination of two or more. In the present invention, the time when the sensitizing dye is added to the silver halide emulsion is preferably the time from the desalting step to the coating, and more preferably the time from desalting to the end of chemical ripening.
The addition amount of the sensitizing dye in the present invention can be set to a desired amount according to the sensitivity and fogging performance, but is preferably 10 ⁻⁶ to 1 mol, more preferably 1 mol per mol of silver halide in the image forming layer. Is 10 ⁻⁴ to 10 ⁻¹ mol.

  In the present invention, a supersensitizer can be used to improve spectral sensitization efficiency. As the supersensitizer used in the present invention, European Patent Publication No. 587,338, US Pat. Nos. 3,877,943, 4,873,184, JP-A-5-341432, 11- 109547, 10-111543, etc. are mentioned.

8) Chemical Sensitization The photosensitive silver halide grain in the invention is preferably chemically sensitized by sulfur sensitization, selenium sensitization or tellurium sensitization. As the compound preferably used in the sulfur sensitization method, selenium sensitization method, and tellurium sensitization method, known compounds such as compounds described in JP-A-7-128768 can be used. In the present invention, tellurium sensitization is particularly preferred. The compounds described in the literature described in paragraph No. 0030 of JP-A-11-65021, and the general formulas (II), (III), (IV) described in JP-A-5-313284 The compound shown by is more preferable.

  The photosensitive silver halide grains in the present invention are preferably chemically sensitized by gold sensitization alone or in combination with the chalcogen sensitization described above. As the gold sensitizer, the valence of gold is preferably +1 or +3, and the gold sensitizer is preferably a commonly used gold compound. Typical examples include chloroauric acid, bromoauric acid, potassium chloroaurate, potassium bromoaurate, auric trichloride, potassium auric thiocyanate, potassium iodoaurate, tetracyanoauric acid, ammonium aurothiocyanate, pyridyltrichlorogold. Etc. are preferable. Further, gold sensitizers described in US Pat. No. 5,858,637 and Japanese Patent Application No. 2001-79450 are also preferably used.

In the present invention, chemical sensitization can be performed at any time after particle formation and before coating. After desalting, (1) before spectral sensitization, (2) simultaneously with spectral sensitization, (3) spectral After sensitization, there may be (4) immediately before application.
The amount of sulfur, selenium and tellurium sensitizers used in the present invention varies depending on the silver halide grains used, chemical ripening conditions, etc., but is 10 ⁻⁸ mol or more and 10 ⁻² mol or less per mol of silver halide, Preferably, about 10 ⁻⁷ mol or more and 10 ⁻³ mol or less is used.
The amount of the gold sensitizer added varies depending on various conditions, but as a guideline, it is 10 ⁻⁷ mol or more and 10 ⁻³ mol or less, more preferably 10 ⁻⁶ mol or more and 5 × 10 ⁻⁴ mol or less per mol of silver halide. It is.
The conditions for chemical sensitization in the present invention are not particularly limited, but the pH is 5 to 8, the pAg is 6 to 11, and the temperature is about 40 to 95 ° C.
A thiosulfonic acid compound may be added to the silver halide emulsion used in the present invention by the method described in European Patent Publication No. 293,917.

    A reducing agent is preferably used for the photosensitive silver halide grains in the present invention. As specific compounds of the reduction sensitization method, ascorbic acid and aminoiminomethanesulfinic acid are preferable. In addition, it is preferable to use stannous chloride, hydrazine derivatives, borane compounds, silane compounds, polyamine compounds, and the like. The reduction sensitizer may be added at any stage in the photosensitive emulsion production process from crystal growth to the preparation process immediately before coating. Further, reduction sensitization is preferable by ripening while maintaining the pH of the emulsion at 7 or more or pAg at 8.3 or less, and reduction sensitization is achieved by introducing a single addition portion of silver ions during grain formation. It is also preferable to do.

9) Compound in which 1-electron oxidant produced by 1-electron oxidation can emit 1 electron or more electrons In the photothermographic material of the present invention, 1-electron oxidant produced by 1-electron oxidation is 1 electron or 1 electron or more. It is preferable to contain a compound capable of emitting more electrons. The compound can be used alone or in combination with the above-described various chemical sensitizers, and can increase the sensitivity of silver halide.

The one-electron oxidant produced by one-electron oxidation contained in the light-sensitive material of the present invention is a compound selected from the following types 1 and 2 that can emit one or more electrons.
The type 1 and type 2 compounds contained in the silver halide photographic light-sensitive material of the present invention will be described.

(Type 1)
A compound in which a one-electron oxidant produced by one-electron oxidation can further emit one or more electrons with a subsequent bond cleavage reaction.
(Type 2)
A compound capable of emitting one or more electrons after a one-electron oxidant produced by one-electron oxidation undergoes a subsequent bond formation reaction.

First, the compound of type 1 will be described.
JP-A-9-211769 (specific example: 28-) is a compound that is a type 1 compound, and a one-electron oxidant produced by one-electron oxidation can further emit one electron with a subsequent bond cleavage reaction. Compounds PMT-1 to S-37 described in Table E and Table F on page 32), JP-A-9-211774, JP-A-11-95355 (specific examples: compounds INV1 to 36), JP2001-500996 (Specific examples: Compounds 1-74, 80-87, 92-122), US Pat. No. 5,747,235, US Pat. No. 5,747,236, European Patent 786692A1 (Specific examples: Compounds INV 1-35), "One-photon two-electron sensitizer" or "deprotonated electron" described in patents such as European Patent No. 893732A1, US Pat. No. 6,054,260, US Pat. No. 5,994,051 Compound called Azukazo sensitizers "it can be mentioned. The preferred ranges of these compounds are the same as the preferred ranges described in the cited patent specifications.

  Further, as a compound of type 1 that can be released by one-electron oxidant generated by one-electron oxidation with subsequent bond cleavage reaction, one or more electrons can be emitted from the general formula (1) ( General formula (1) described in JP-A-2003-114487), general formula (2) (synonymous with general formula (2) described in JP-A-2003-114487), general formula (3) (JP-A-2003-114487) General formula (1) described in 2003-114488), general formula (4) (synonymous with general formula (2) described in Japanese Patent Application Laid-Open No. 2003-114488), and general formula (5) (Japanese Patent Application Laid-Open No. 2003-114488). 114488 (synonymous with general formula (3)), general formula (6) (synonymous with general formula (1) described in JP-A-2003-75950), and general formula (7) (JP-A-2003-75950). In the general formula (2)), the general formula (8) (Synonymous with the general formula (1) described in Japanese Patent Application No. 2003-25886), or the reaction represented by the chemical reaction formula (1) (synonymous with the chemical reaction formula (1) described in Japanese Patent Application No. 2003-33446). Among the compounds that can cause the above, there can be mentioned a compound represented by the general formula (9) (synonymous with the general formula (3) described in Japanese Patent Application No. 2003-33446). The preferred ranges of these compounds are the same as the preferred ranges described in the cited patent specifications.

In the general formulas (1) and (2), RED ₁ and RED ₂ represent a reducing group. R ₁ is a non-metallic atomic group capable of forming a cyclic structure corresponding to a tetrahydro form of a 5- or 6-membered aromatic ring (including an aromatic heterocycle) or a hexahydro form together with carbon atom (C) and RED _1. Represent. R ₂ , R ₃ and R ₄ represent a hydrogen atom or a substituent. Lv ₁ and Lv ₂ represent a leaving group. ED represents an electron donating group.

In the general formulas (3), (4) and (5), Z ₁ represents an atomic group capable of forming a 6-membered ring with a nitrogen atom and two carbon atoms of the benzene ring. _{R 5, R 6, R 7} , R 9, R 10, R 11, R 13, R 14, R 15, R 16, R 17, R 18, R 19 represents a hydrogen atom or a substituent. R ₂₀ represents a hydrogen atom or a substituent. When R ₂₀ represents a group other than an aryl group, R ₁₆ and R ₁₇ are bonded to each other to form an aromatic ring or an aromatic heterocycle. R ₈ and R ₁₂ represent a substituent that can be substituted on the benzene ring, m1 represents an integer of 0 to 3, and m2 represents an integer of 0 to 4. Lv ₃ , Lv ₄ and Lv ₅ represent a leaving group.

In the general formulas (6) and (7), RED ₃ and RED ₄ represent a reducing group. R _{21 to} R ₃₀ represent a hydrogen atom or a substituent. Z ₂ represents —CR ₁₁₁ R ₁₁₂ —, —NR ₁₁₃ —, or —O—. R ₁₁₁ and R ₁₁₂ each independently represents a hydrogen atom or a substituent. _R113 represents a hydrogen atom, an alkyl group, an aryl group, or a heterocyclic group.

In the general formula (8), RED ₅ is a reducing group and represents an arylamino group or a heterocyclic amino group. R ₃₁ represents a hydrogen atom or a substituent. X represents an alkoxy group, an aryloxy group, a heterocyclic oxy group, an alkylthio group, an arylthio group, a heterocyclic thio group, an alkylamino group, an arylamino group, or a heterocyclic amino group. Lv ₆ is a leaving group and represents a carboxy group or a salt thereof or a hydrogen atom.

The compound represented by the general formula (9) is a compound that undergoes a bond formation reaction represented by the chemical reaction formula (1) by being further oxidized after two-electron oxidation accompanied by decarboxylation has occurred. In the chemical reaction formula (1), R ₃₂ and R ₃₃ represent a hydrogen atom or a substituent. Z ₃ represents a group which forms a 5-membered or 6-membered heterocycle with C═C. Z ₄ represents a group which forms a 5- or 6-membered aryl group or heterocyclic group with C═C. M represents a radical, a radical cation, or a cation. In the general formula (9), R ₃₂ , R ₃₃ and Z ₃ have the same meaning as in the chemical reaction formula (1). Z ₅ represents a group which forms a 5- or 6-membered cyclic aliphatic hydrocarbon group or heterocyclic group together with C—C.

Next, the type 2 compound will be described.
As a compound in which a one-electron oxidant produced by one-electron oxidation with a type 2 compound can further emit one or more electrons with a subsequent bond formation reaction, a compound represented by the general formula (10) A compound capable of causing a reaction represented by the general formula (1) described in 2003-140287) and the chemical reaction formula (1) (synonymous with the chemical reaction formula (1) described in Japanese Patent Application No. 2003-33446). And a compound represented by the general formula (11) (synonymous with the general formula (2) described in Japanese Patent Application No. 2003-33446). The preferred ranges of these compounds are the same as the preferred ranges described in the cited patent specifications.

General formula (10); RED ₆ -QY

In the general formula (10), RED ₆ represents a reducing group that is oxidized one electron. Y reacts with a one-electron oxidant formed by one-electron oxidation of RED ₆ to form a new bond, a carbon-carbon double bond site, a carbon-carbon triple bond site, an aromatic group site, or Reactive group containing a non-aromatic heterocyclic moiety of a benzo-fused ring. Q represents a linking group for linking RED ₆ and Y.

The compound represented by the general formula (11) is a compound that causes a bond formation reaction represented by the chemical reaction formula (1) by being oxidized. In the chemical reaction formula (1), R ₃₂ and R ₃₃ represent a hydrogen atom or a substituent. Z ₃ represents a group which forms a 5-membered or 6-membered heterocycle with C═C. Z ₄ represents a group which forms a 5- or 6-membered aryl group or heterocyclic group with C═C. Z ₅ represents a group which forms a 5- or 6-membered cyclic aliphatic hydrocarbon group or heterocyclic group together with C—C. M represents a radical, a radical cation, or a cation. In the general formula (11), R ₃₂ , R ₃₃ , Z ₃ and Z ₄ have the same meanings as those in the chemical reaction formula (1).

  Of the compounds of types 1 and 2, “a compound having an adsorptive group to silver halide in the molecule” or “a compound having a partial structure of a spectral sensitizing dye in the molecule” is preferable. Typical examples of the adsorptive group to silver halide are those described in JP-A No. 2003-156823, page 16, right line 1 to page 17, right line 12. The partial structure of the spectral sensitizing dye is a structure described on page 17, right line 34 to page 18, left line 6 of the same specification.

  More preferably, the compound of type 1 or 2 is “a compound having at least one adsorptive group to silver halide in the molecule”. More preferred is “a compound having two or more adsorptive groups to silver halide in the same molecule”. When two or more adsorptive groups are present in a single molecule, these adsorptive groups may be the same or different.

  The adsorptive group is preferably a mercapto-substituted nitrogen-containing heterocyclic group (for example, 2-mercaptothiadiazole group, 3-mercapto-1,2,4-triazole group, 5-mercaptotetrazole group, 2-mercapto-1,3,4). -Oxadiazole group, 2-mercaptobenzoxazole group, 2-mercaptobenzthiazole group, 1,5-dimethyl-1,2,4-triazolium-3-thiolate group, etc.) or imino silver (> NAg) And a nitrogen-containing heterocyclic group having a —NH— group as a heterocyclic partial structure (for example, a benzotriazole group, a benzimidazole group, an indazole group, etc.). Particularly preferred are 5-mercaptotetrazole group, 3-mercapto-1,2,4-triazole group, and benzotriazole group, most preferred are 3-mercapto-1,2,4-triazole group, and 5 -Mercaptotetrazole group.

  It is also particularly preferred that the adsorptive group has two or more mercapto groups as a partial structure in the molecule. Here, the mercapto group (—SH) may be a thione group if it can be tautomerized. Preferred examples of the adsorptive group having two or more mercapto groups as a partial structure (such as a dimercapto-substituted nitrogen-containing heterocyclic group) include 2,4-dimercaptopyrimidine group, 2,4-dimercaptotriazine group, 3, A 5-dimercapto-1,2,4-triazole group may be mentioned.

  A quaternary salt structure of nitrogen or phosphorus is also preferably used as the adsorptive group. Specific examples of the quaternary salt structure of nitrogen include an ammonio group (such as a trialkylammonio group, a dialkylaryl (or heteroaryl) ammonio group, an alkyldiaryl (or heteroaryl) ammonio group) or a quaternized nitrogen atom. A group containing a nitrogen-containing heterocyclic group containing As the quaternary salt structure of phosphorus, a phosphonio group (trialkylphosphonio group, dialkylaryl (or heteroaryl) phosphonio group, alkyldiaryl (or heteroaryl) phosphonio group, triaryl (or heteroaryl) phosphonio group, etc.) is used. Can be mentioned. More preferably, a quaternary salt structure of nitrogen is used, and more preferably a 5-membered or 6-membered nitrogen-containing aromatic heterocyclic group containing a quaternized nitrogen atom is used. Particularly preferably, a pyridinio group, a quinolinio group, or an isoquinolinio group is used. These nitrogen-containing heterocyclic groups containing a quaternized nitrogen atom may have an arbitrary substituent.

Examples of counter anions of quaternary salts include halogen ions, carboxylate ions, sulfonate ions, sulfate ions, perchlorate ions, carbonate ions, nitrate ions, BF ₄ ⁻ , PF ₆ ⁻ , Ph ₄ B ^{− and the} like. It is done. When a group having a negative charge in the carboxylate group or the like is present in the molecule, an inner salt may be formed together with the group. As the counter anion not present in the molecule, a chlorine ion, a bromo ion or a methanesulfonate ion is particularly preferable.

  A preferred structure of the compound represented by type 1 or 2 having a quaternary salt structure of nitrogen or phosphorus as the adsorptive group is represented by the general formula (X).

Formula (X); (PQ _1- ) _i -R (-Q ₂ -S) _j

In general formula (X), P and R each independently represent a quaternary salt structure of nitrogen or phosphorus that is not a partial structure of a sensitizing dye. Q ₁ and Q ₂ each independently represent a linking group, specifically a single bond, an alkylene group, an arylene group, a heterocyclic group, —O—, —S—, —NR _N —, —C (═O ) —, —SO ₂ —, —SO—, —P (═O) — each independently or a combination of these groups. Here, _RN represents a hydrogen atom, an alkyl group, an aryl group, or a heterocyclic group. S is a residue obtained by removing one atom from a compound represented by type (1) or (2). i and j are integers of 1 or more, and i + j is selected from the range of 2-6. Preferably, i is 1 to 3, and j is 1 to 2, more preferably i is 1 or 2, and j is 1, and particularly preferably i is 1 and j is 1. The compound represented by the general formula (X) preferably has a total carbon number of 10 to 100. More preferably, it is 10-70, More preferably, it is 11-60, Most preferably, it is 12-50.

  Specific examples of the compounds represented by type 1 and type 2 are listed below, but the present invention is not limited thereto.

  The compounds of type 1 and type 2 in the present invention may be used at any time during the preparation of the emulsion and during the light-sensitive material production process. For example, at the time of particle formation, desalting step, chemical sensitization, and before coating. Moreover, it can also add in several steps in these processes. The addition position is preferably from the end of particle formation to before the desalting step, at the time of chemical sensitization (from immediately before the start of chemical sensitization to immediately after the end), and before application, more preferably at the time of chemical sensitization and before application.

  The compounds of type 1 and type 2 in the present invention are preferably added after being dissolved in water, a water-soluble solvent such as methanol or ethanol, or a mixed solvent thereof. When the compound is dissolved in water, the compound having higher solubility when the pH is increased or decreased may be dissolved at a higher or lower pH and added.

The compounds of type 1 and type 2 in the present invention are preferably used in the emulsion layer (image forming layer), but may be added to the protective layer and intermediate layer together with the image forming layer and diffused during coating. The timing of addition of the compound of the present invention is preferably 1 × 10 ⁻⁹ mol or more and 5 × 10 ⁻² mol or less, more preferably 1 × 10 ⁻⁸ mol per mol of silver halide, regardless of before and after the sensitizing dye. It is contained in the silver halide emulsion layer (image forming layer) in a proportion of from 1 mol to 2 × 10 ⁻³ mol.

10) Adsorbing redox compound having an adsorbing group and a reducing group In the present invention, an adsorbing redox compound having an adsorbing group and a reducing group for silver halide is preferably contained in the molecule. The adsorptive redox compound is preferably a compound represented by the following formula (I).

Formula (I) A- (W) n-B
In formula (I), A represents a group that can be adsorbed to silver halide (hereinafter referred to as an adsorbing group), W represents a divalent linking group, n represents 0 or 1, and B represents a reducing group. Represent.

  In the formula (I), the adsorption group represented by A is a group that directly adsorbs to silver halide, or a group that promotes adsorption to silver halide, and specifically, a mercapto group (or a salt thereof). , A thione group (—C (═S) —), a heterocyclic group, a sulfide group, a disulfide group, a cationic group, or an ethynyl group containing at least one atom selected from a nitrogen atom, a sulfur atom, a selenium atom, and a tellurium atom Etc.

The mercapto group (or salt thereof) as the adsorptive group means the mercapto group (or salt thereof) itself, and more preferably a heterocyclic group or aryl group substituted with at least one mercapto group (or salt thereof) or Represents an alkyl group. Here, the heterocyclic group is at least a 5- to 7-membered monocyclic or condensed aromatic or non-aromatic heterocyclic group such as an imidazole ring group, a thiazole ring group, an oxazole ring group, or a benzimidazole ring. Group, benzothiazole ring group, benzoxazole ring group, triazole ring group, thiadiazole ring group, oxadiazole ring group, tetrazole ring group, purine ring group, pyridine ring group, quinoline ring group, isoquinoline ring group, pyrimidine ring group, And triazine ring group. Moreover, the heterocyclic group containing the quaternized nitrogen atom may be sufficient, and in this case, the substituted mercapto group may dissociate and it may become a meso ion. When the mercapto group forms a salt, the counter ion is a cation such as an alkali metal, alkaline earth metal or heavy metal (Li ⁺ , Na ⁺ , K ⁺ , Mg ²⁺ , Ag ⁺ , Zn ²⁺ etc.), ammonium ion Examples thereof include a heterocyclic group containing a quaternized nitrogen atom, a phosphonium ion, and the like.
Further, the mercapto group as the adsorptive group may be tautomerized into a thione group.
The thione group as an adsorbing group also includes a chain or cyclic thioamide group, thioureido group, thiourethane group, or dithiocarbamate group.
A heterocyclic group containing at least one atom selected from a nitrogen atom, a sulfur atom, a selenium atom and a tellurium atom as the adsorptive group is a -NH- group capable of forming imino silver (> NAg) as a partial structure of the heterocyclic ring. A nitrogen-containing heterocyclic group, or a heterocyclic ring having a -S- group, a -Se- group, a -Te- group, or a = N- group as a partial structure of the heterocyclic ring, which can be coordinated to a silver ion by a coordination bond Examples of the former include benzotriazole group, triazole group, indazole group, pyrazole group, tetrazole group, benzimidazole group, imidazole group, and purine group, and examples of the latter include thiophene group, thiazole group, and oxazole group. , Benzothiophene group, benzothiazole group, benzoxazole group, thiadiazole group, oxadiazole group, triazine group, seleno Tetrazole group, benzoselenazole group, tellurium azole group, such as benzo tellurium azole group.
Examples of the sulfide group or disulfide group as the adsorptive group include all groups having a partial structure of -S- or -SS-.
The cationic group as the adsorptive group means a group containing a quaternized nitrogen atom, specifically, an ammonio group or a group containing a nitrogen-containing heterocyclic group containing a quaternized nitrogen atom. Examples of the nitrogen-containing heterocyclic group containing a quaternized nitrogen atom include a pyridinio group, a quinolinio group, an isoquinolinio group, an imidazolio group, and the like.
An ethynyl group as an adsorptive group means a —C≡CH group, and the hydrogen atom may be substituted.
The adsorbing group may have an arbitrary substituent.

  Further, specific examples of the adsorbing group include those described in the specifications p4 to p7 of JP-A No. 11-95355.

  In the formula (I), preferred as the adsorptive group represented by A is a mercapto-substituted heterocyclic group (for example, 2-mercaptothiadiazole group, 2-mercapto-5-aminothiadiazole group, 3-mercapto-1,2,4). -Triazole group, 5-mercaptotetrazole group, 2-mercapto-1,3,4-oxadiazole group, 2-mercaptobenzimidazole group, 1,5-dimethyl-1,2,4-triazolium-3-thiolate group 2,4-dimercaptopyrimidine group, 2,4-dimercaptotriazine group, 3,5-dimercapto-1,2,4-triazole group, 2,5-dimercapto-1,3-thiazole group), or Nitrogen-containing heterocyclic group having —NH— group capable of forming imino silver (> NAg) as a partial structure of heterocyclic ring (for example, benzotriazo Group, benzimidazole group, an indazole group), more preferable as an adsorptive group is a 2-mercaptobenzimidazole group, a 3,5-dimercapto-1,2,4-triazole group.

In formula (I), W represents a divalent linking group. Any linking group may be used as long as it does not adversely affect photographic properties. For example, a divalent linking group composed of a carbon atom, a hydrogen atom, an oxygen atom, a nitrogen atom, or a sulfur atom can be used. Specifically, an alkylene group having 1 to 20 carbon atoms (for example, a methylene group, an ethylene group, a trimethylene group, a tetramethylene group, a hexamethylene group, etc.), an alkenylene group having 2 to 20 carbon atoms, and an alkynylene group having 2 to 20 carbon atoms. , An arylene group having 6 to 20 carbon atoms (eg, phenylene group, naphthylene group, etc.), —CO—, —SO ₂ —, —O—, —S—, —NR ₁ —, combinations of these linking groups, and the like. It is done. Here, R ₁ represents a hydrogen atom, an alkyl group, a heterocyclic group, or an aryl group.
The linking group represented by W may have an arbitrary substituent.

  In formula (I), the reducing group represented by B represents a group capable of reducing silver ions. For example, a triple bond group such as formyl group, amino group, acetylene group or propargyl group, mercapto group, hydroxylamines. Hydroxamic acids, hydroxyureas, hydroxyurethanes, hydroxysemicarbazides, reductones (including reductone derivatives), anilines, phenols (chroman-6-ols, 2,3-dihydrobenzofuran-5-ols, (Including aminophenols, sulfonamidophenols, and hydroquinones, catechols, resorcinols, polyphenols such as benzenetriols, bisphenols), acylhydrazines, carbamoylhydrazines, 3-pyrazolidones, etc. Residue with one removed And the like. Of course, these may have an arbitrary substituent.

In the formula (I), the reducing group represented by B shows its oxidation potential by Akira Fujishima “Electrochemical measurement method” (pages 150-208, published by Gihodo) or “The Experimental Chemistry Course” edited by the Chemical Society of Japan, 4th edition ( 9 pages 282-344, Maruzen). For example, by a rotating disk voltammetry technique, specifically, a sample is dissolved in a solution of methanol: pH 6.5 Briton-Robinson buffer = 10%: 90% (volume%), and nitrogen gas is used for 10 minutes. , A glassy carbon rotating disk electrode (RDE) is used as a working electrode, a platinum wire is used as a counter electrode, a saturated calomel electrode is used as a reference electrode, 25 ° C., 1000 rev / min, 20 mV / sec. Can be measured at sweep speed. A half-wave potential (E1 / 2) can be obtained from the obtained voltammogram.
In the present invention, the reducing group represented by B preferably has an oxidation potential in the range of about -0.3 V to about 1.0 V when measured by the above measurement method. More preferably, it is in the range of about -0.1V to about 0.8V, and particularly preferably in the range of about 0 to about 0.7V.

  In the formula (I), the reducing group represented by B is preferably selected from hydroxylamines, hydroxamic acids, hydroxyureas, hydroxysemicarbazides, reductones, phenols, acylhydrazines, carbamoylhydrazines, and 3-pyrazolidones. A residue obtained by removing one hydrogen atom.

  The compound of the formula (I) in the present invention may be one in which a ballast group or polymer chain commonly used in an immobile photographic additive such as a coupler is incorporated. Examples of the polymer include those described in JP-A-1-100530.

  The compound of the formula (I) in the present invention may be a bis form or a tris form. The molecular weight of the compound of formula (I) in the present invention is preferably between 100 and 10000, more preferably between 120 and 1000, particularly preferably between 150 and 500.

  Examples of the compound of formula (I) in the present invention are shown below, but the present invention is not limited thereto.

  Further, specific compounds 1 to 30 and 1 ″ -1 to 1 ″ -77 described in European Patent No. 1308776A2 P73 to P87 are also preferable examples of the compound having an adsorbing group and a reducing group in the present invention. .

  These compounds can be easily synthesized according to known methods. As the compound of the formula (I) in the present invention, one kind of compound may be used alone, but it is also preferred to use two or more kinds of compounds at the same time. When two or more kinds of compounds are used, they may be added in the same layer or in different layers, and the addition methods may be different.

The compound of formula (I) in the present invention is preferably added to the silver halide emulsion layer, and more preferably added during preparation of the emulsion. When added at the time of emulsion preparation, it can be added at any time during the process. For example, silver halide grain formation process, before the start of desalting process, desalting process, chemical ripening Examples include a step before starting, a chemical ripening step, and a step before preparing a finished emulsion. Moreover, it can also be added in several steps in these processes. Although it is preferably used for the image forming layer, it may be added to the adjacent protective layer or intermediate layer together with the image forming layer and diffused during coating.
The preferred addition amount largely depends on the above-mentioned addition method and the kind of compound to be added, but generally 1 × 10 ⁻⁶ mol to 1 mol, preferably 1 × 10 ⁻⁵ mol, per mol of photosensitive silver halide. The amount is 5 × 10 ⁻¹ mol or less, more preferably 1 × 10 ⁻⁴ mol or more and 1 × 10 ⁻¹ mol or less.

  The compound of the formula (I) in the present invention can be added after being dissolved in water, a water-soluble solvent such as methanol or ethanol, or a mixed solvent thereof. At this time, the pH may be appropriately adjusted with an acid or a base, and a surfactant may be allowed to coexist. Furthermore, it can also be dissolved in a high boiling point organic solvent and added as an emulsified dispersion. It can also be added as a solid dispersion.

11) Multiple silver halides in combination The photosensitive 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 having different average grain sizes, those having different halogen compositions, Those having different crystal habits and different chemical sensitization conditions may be used in combination. The gradation can be adjusted by using a plurality of types of photosensitive silver halides having different sensitivities. Examples of these technologies include JP-A-57-119341, 53-106125, 47-3929, 48-55730, 46-5187, 50-73627, 57-150841 and the like. Can be mentioned. The sensitivity difference is preferably 0.2 log E or more for each emulsion.

12) Application amount The addition amount of photosensitive silver halide is preferably 0.03 g / m ² or more and 0.6 g / m ² or less, expressed as the amount of silver applied per 1 m ² of the light-sensitive material. / M ² or more and 0.4 g / m ² or less is more preferable, and 0.07 g / m ² or more and 0.3 g / m ² or less is most preferable. The functional silver halide is preferably from 0.01 mol to 0.5 mol, more preferably from 0.02 mol to 0.3 mol, and still more preferably from 0.03 mol to 0.2 mol.

13) Mixing of photosensitive silver halide and organic silver salt Regarding the mixing method and mixing conditions of separately prepared photosensitive silver halide and organic silver salt, the silver halide grains and the organic silver salt that were prepared respectively were stirred at high speed. Prepare an organic silver salt by mixing with a machine, ball mill, sand mill, colloid mill, vibration mill, homogenizer, etc., or by mixing photosensitive silver halide that has been prepared at any time during the preparation of the organic silver salt However, there is no particular limitation as long as the effects of the present invention are sufficiently exhibited. Moreover, mixing two or more organic silver salt aqueous dispersions and two or more photosensitive silver salt aqueous dispersions when mixing is a preferred method for adjusting photographic characteristics.

14) Mixing of silver halide into coating solution The preferred addition time of silver halide into the image forming layer coating solution is from 180 minutes before application, preferably from 60 minutes to 10 seconds before application. The method and mixing conditions are not particularly limited as long as the effects of the present invention are sufficiently exhibited. Specific mixing methods include mixing in a tank in which the average residence time calculated from the addition flow rate and the amount of liquid fed to the coater is a desired time, and N.I. Harnby, M.M. F. Edwards, A.D. W. There is a method using a static mixer described in Chapter 8 of Nienow's “Liquid Mixing Technology” (Nikkan Kogyo Shimbun, 1989), translated by Koji Takahashi.

(Description of binder)
Any polymer may be used as the binder of the image-forming layer in the present invention. Suitable binders are transparent or translucent and generally colorless, and are natural resins, polymers and copolymers, synthetic resins, polymers and copolymers, and other films. Forming media such as gelatins, gums, poly (vinyl alcohol) s, hydroxyethyl celluloses, cellulose acetates, cellulose acetate butyrates, poly (vinyl pyrrolidone) s, casein, starch, poly (acrylic acid) , Poly (methyl methacrylic acid) s, poly (vinyl chloride) s, poly (methacrylic acid) s, styrene-maleic anhydride copolymers, styrene-acrylonitrile copolymers, styrene-butadiene copolymers, Poly (vinyl acetal) s (for example, poly (vinyl acetal) (Formal) and poly (vinyl butyral)), poly (esters), poly (urethane) s, phenoxy resins, poly (vinylidene chloride) s, poly (epoxides), poly (carbonates), poly (vinyl acetate) s , Poly (olefin) s, cellulose esters, and poly (amides). The binder may be formed from water, an organic solvent or an emulsion.

  In the present invention, the binder that can be used in the layer containing the organic silver salt preferably has a glass transition temperature of 0 ° C. or higher and 80 ° C. or lower (hereinafter sometimes referred to as a high Tg binder), and is 10 ° C. or higher and 70 ° C. or lower. More preferably, it is 15 ° C. or more and 60 ° C. or less.

In this specification, Tg was calculated by the following formula.
1 / Tg = Σ (Xi / Tgi)
Here, it is assumed that n monomer components from i = 1 to n are copolymerized in the polymer. Xi is the weight fraction of the i-th monomer (ΣXi = 1), and Tgi is the glass transition temperature (absolute temperature) of the homopolymer of the i-th monomer. However, Σ is the sum from i = 1 to n. The homopolymer glass transition temperature (Tgi) of each monomer was the value of Polymer Handbook (3rd Edition) (by J. Brandrup, EH Immergut (Wiley-Interscience, 1989)).

  Two or more binders may be used in combination as required. Further, a glass transition temperature of 20 ° C. or higher and a glass transition temperature of less than 20 ° C. may be used in combination. When two or more kinds of polymers having different Tg are blended, the weight average Tg is preferably within the above range.

In the present invention, it is preferable that the image forming layer is coated and dried using a coating solution in which 30% by mass or more of the solvent is water to form a film.
In the present invention, when the image forming layer is formed using a coating solution in which 30% by mass or more of the solvent is water and dried, the binder of the image forming layer is further added to an aqueous solvent (aqueous solvent). When it is soluble or dispersible, the performance is improved particularly when it is made of a latex of a polymer having an equilibrium water content of 2% by mass or less at 25 ° C. and 60% RH. The most preferable form is one prepared so that the ionic conductivity is 2.5 mS / cm or less, and as such a preparation method, there is a method of performing purification treatment using a separation functional membrane after polymer synthesis.

  The aqueous solvent in which the polymer is soluble or dispersible here is a mixture of water or water and 70% by mass or less of a water-miscible organic solvent. Examples of the water-miscible organic solvent include alcohols such as methyl alcohol, ethyl alcohol, and propyl alcohol, cellosolvs such as methyl cellosolve, ethyl cellosolve, and butyl cellosolve, ethyl acetate, and dimethylformamide.

  In the case of a system in which the polymer is not dissolved thermodynamically and exists in a so-called dispersed state, the term aqueous solvent is used here.

The “equilibrium moisture content at 25 ° C. and 60% RH” is the following using the weight W1 of the polymer in the humidity-controlled equilibrium under the atmosphere of 25 ° C. and 60% RH and the weight W0 of the polymer in the absolutely dry state at 25 ° C. It can be expressed as
Equilibrium moisture content at 25 ° C. and 60% RH = {(W1−W0) / W0} × 100 (mass%)

  For the definition and measurement method of moisture content, for example, Polymer Engineering Course 14, Polymer Material Testing Method (Edited by Society of Polymer Sciences, Jinshokan) can be referred to.

  The equilibrium water content at 25 ° C. and 60% RH of the binder polymer in the present invention is preferably 2% by mass or less, more preferably 0.01% by mass or more and 1.5% by mass or less, and further preferably 0.02 Desirably, the content is from 1% by mass to 1% by mass.

  In the present invention, a polymer dispersible in an aqueous solvent is particularly preferred. Examples of the dispersed state may be either latex in which fine particles of water-insoluble hydrophobic polymer are dispersed or polymer molecules dispersed in a molecular state or forming micelles. preferable. The average particle size of the dispersed particles is 1 nm or more and 50000 nm or less, preferably 5 nm or more and 1000 nm or less, more preferably 10 nm or more and 500 nm or less, and further preferably 50 nm or more and 200 nm or less. The particle size distribution of the dispersed particles is not particularly limited, and may have a wide particle size distribution or a monodispersed particle size distribution. Mixing two or more types having a monodispersed particle size distribution is also a preferable method for controlling the physical properties of the coating solution.

  In the present invention, preferred embodiments of the polymer that can be dispersed in an aqueous solvent include acrylic polymers, poly (esters), rubbers (eg, SBR resin), poly (urethanes), poly (vinyl chloride) s, poly (acetic acid). Hydrophobic polymers such as vinyl), poly (vinylidene chloride) and poly (olefin) can be preferably used. These polymers may be linear polymers, branched polymers, crosslinked polymers, so-called homopolymers obtained by polymerizing a single monomer, or copolymers obtained by polymerizing two or more types of monomers. In the case of a copolymer, it may be a random copolymer or a block copolymer. The molecular weight of these polymers is 5,000 to 1,000,000, preferably 10,000 to 200,000 in terms of number average molecular weight. When the molecular weight is too small, the mechanical strength of the image forming layer is insufficient, and when the molecular weight is too large, the film formability is poor, which is not preferable. A crosslinkable polymer latex is particularly preferably used.

(Specific examples of latex)
Specific examples of preferable polymer latex include the following. Below, it represents using a raw material monomer, the numerical value in a parenthesis is the mass%, and molecular weight is a number average molecular weight. When a polyfunctional monomer was used, the concept of molecular weight was not applicable because a crosslinked structure was formed, so it was described as crosslinkability, and the description of molecular weight was omitted. Tg represents the glass transition temperature.

-P-1; latex of -MMA (70) -EA (27) -MAA (3)-(molecular weight 37000, Tg 61 ° C.)
-Latex of P-2; -MMA (70) -2EHA (20) -St (5) -AA (5)-(molecular weight 40000, Tg 59 ° C.)
-P-3; Latex of -St (50) -Bu (47) -MAA (3)-(crosslinkability, Tg-17 ° C)
-P-4; Latex of -St (68) -Bu (29) -AA (3)-(crosslinkability, Tg 17 ° C)
-P-5; Latex of -St (71) -Bu (26) -AA (3)-(crosslinkability, Tg 24 ° C)
-P-6; -St (70) -Bu (27) -IA (3)-latex (crosslinkable)
-P-7; Latex of -St (75) -Bu (24) -AA (1)-(crosslinkability, Tg 29 ° C.)
-P-8; Latex (crosslinkability) of -St (60) -Bu (35) -DVB (3) -MAA (2)-
-Latex (crosslinkable) of P-9; -St (70) -Bu (25) -DVB (2) -AA (3)-
-Latex (molecular weight 80,000) of P-10; -VC (50) -MMA (20) -EA (20) -AN (5) -AA (5)-
-P-11; latex of -VDC (85) -MMA (5) -EA (5) -MAA (5)-(molecular weight 67000)
-P-12; -Et (90) -MAA (10)-latex (molecular weight 12000)
-P-13; Latex of -St (70) -2EHA (27) -AA (3) (molecular weight 130,000, Tg 43 ° C)
-P-14; -MMA (63) -EA (35) -AA (2) latex (molecular weight 33000, Tg 47 ° C.)
-P-15; Latex of -St (70.5) -Bu (26.5) -AA (3)-(crosslinkability, Tg 23 ° C.)
-P-16; Latex of -St (69.5) -Bu (27.5) -AA (3)-(crosslinkability, Tg 20.5 ° C)

  The abbreviations for the above structures represent the following monomers. MMA; methyl methacrylate, EA; ethyl acrylate, MAA; methacrylic acid, 2EHA; 2-ethylhexyl acrylate, St; styrene, Bu; butadiene, AA; acrylic acid, DVB; divinylbenzene, VC; vinyl chloride, AN; Vinylidene chloride, Et; ethylene, IA; itaconic acid.

  The polymer latex described above is also commercially available, and the following polymers can be used. Examples of the acrylic polymer include Sebian A-4635, 4718, 4601 (manufactured by Daicel Chemical Industries, Ltd.), Nipol Lx811, 814, 821, 820, 857 (manufactured by Nippon Zeon Co., Ltd.), etc. Examples of poly (esters) include poly (urethane) such as FINETEX ES650, 611, 675, 850 (above, Dainippon Ink Chemical Co., Ltd.), WD-size, WMS (above, Eastman Chemical). Examples of rubbers include HYDRAN AP10, 20, 30, 40 (above, manufactured by Dainippon Ink Chemical Co., Ltd.), and examples of rubbers include LACSTAR 7310K, 3307B, 4700H, 7132C (above, Dainippon Ink Chemical Co., Ltd.). (Made by Co., Ltd.), Nipol Lx416, 410, 438C, 2507 As examples of poly (vinyl chloride) such as G351 and G576 (above, manufactured by Nippon Zeon Co., Ltd.), examples of poly (vinylidene chloride) such as L502, L513 (above Examples of poly (olefin) s such as Asahi Kasei Kogyo Co., Ltd. include Chemipearl S120 and SA100 (above, Mitsui Chemicals, Inc.).

  These polymer latexes may be used alone or in combination of two or more as required.

(Preferred latex)
As the polymer latex used in the present invention, a styrene-butadiene copolymer latex is particularly preferable. The weight ratio of the styrene monomer unit to the butadiene monomer unit in the styrene-butadiene copolymer is preferably 40:60 to 95: 5. The proportion of the styrene monomer unit and the butadiene monomer unit in the copolymer is preferably 60 to 99% by mass. Moreover, it is preferable that the polymer latex in this invention contains 1-6 mass% of acrylic acid or methacrylic acid with respect to the sum of styrene and butadiene, More preferably, it contains 2-5 mass%. The polymer latex in the present invention preferably contains acrylic acid. The preferred molecular weight range is the same as described above.

  Examples of latexes of styrene-butadiene acid copolymer that are preferably used in the present invention include the aforementioned P-3 to P-8,15, commercially available LACSTAR-3307B, 7132C, Nipol Lx416, and the like.

  If necessary, a hydrophilic polymer such as gelatin, polyvinyl alcohol, methylcellulose, hydroxypropylcellulose, carboxymethylcellulose may be added to the image forming layer of the light-sensitive material of the present invention. The amount of these hydrophilic polymers added is preferably 30% by mass or less, more preferably 20% by mass or less, based on the total binder of the image forming layer.

  The organic silver salt-containing layer (that is, the image forming layer) in the present invention is preferably formed using a polymer latex. The amount of binder in the image forming layer is such that the weight ratio of total binder / organic silver salt is 1/10 to 10/1, more preferably 1/3 to 5/1, and still more preferably 1/1 to 3/1. Range.

  Further, such an organic silver salt-containing layer is usually a photosensitive layer (image forming layer) containing a photosensitive silver halide which is a photosensitive silver salt. The weight ratio of silver halide is in the range of 400-5, more preferably 200-10.

The total binder amount of the image forming layer in the present invention is preferably 0.2 g / m ² or more and 30 g / m ² or less, more preferably 1 g / m ² or more and 15 g / m ² or less, and further preferably 2 g / m ² or more and 10 g. / M ² or less. In the image forming layer of the present invention, a crosslinking agent for crosslinking, a surfactant for improving coating properties, and the like may be added.

(Preferable solvent for coating solution)
In the present invention, the solvent of the image forming layer coating solution of the light-sensitive material (for simplicity, the solvent and the dispersion medium are collectively referred to as a solvent) is preferably an aqueous solvent containing 30% by mass or more of water. As a component other than water, any water-miscible organic solvent such as methyl alcohol, ethyl alcohol, isopropyl alcohol, methyl cellosolve, ethyl cellosolve, dimethylformamide, and ethyl acetate may be used. The water content of the solvent of the coating solution is preferably 50% by mass or more, more preferably 70% by mass or more. Examples of preferred solvent compositions include water, water / methyl alcohol = 90/10, water / methyl alcohol = 70/30, water / methyl alcohol / dimethylformamide = 80/15/5, water / methyl alcohol / Ethyl cellosolve = 85/10/5, water / methyl alcohol / isopropyl alcohol = 85/10/5, etc. (numerical values are mass%).

(Description of antifogging agent)
Antifoggants, stabilizers and stabilizer precursors which can be used in the present invention are disclosed in paragraph No. 0070 of JP-A-10-62899, page 20, line 57 to page 21, line 7 of European Patent Publication No. 0803764A1. And the compounds described in JP-A-9-281737 and JP-A-9-329864, and the compounds described in US Pat. No. 6,083,681 and European Patent 1048875.

(Description of polyhalogen compounds)
Hereinafter, preferred organic polyhalogen compounds that can be used in the present invention will be specifically described. A preferred polyhalogen compound in the present invention is a compound represented by the following general formula (H).
General formula (H)
Q- (Y) n-C (Z ₁ ) (Z ₂ ) X
In general formula (H), Q represents an alkyl group, an aryl group or a heterocyclic group, Y represents a divalent linking group, n represents 0 to ₁ , Z ₁ and Z ₂ represent a halogen atom, X represents a hydrogen atom or an electron withdrawing group.
In the general formula (H), Q is preferably an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a heterocyclic group containing at least one nitrogen atom (pyridine, quinoline group, etc.).
In the general formula (H), when Q is an aryl group, Q preferably represents a phenyl group substituted with an electron-attracting group having a positive Hammett's substituent constant σp. For Hammett's substituent constants, see Journal of Medicinal Chemistry, 1973, Vol. 16, no. 11, 1207-1216 etc. can be referred to. Examples of such an electron withdrawing group include a halogen atom, an alkyl group substituted with an electron withdrawing group, an aryl group substituted with an electron withdrawing group, a heterocyclic group, an alkyl or arylsulfonyl group, acyl Group, alkoxycarbonyl group, carbamoyl group, sulfamoyl group and the like. Particularly preferred as the electron withdrawing group are a halogen atom, a carbamoyl group and an arylsulfonyl group, and a carbamoyl group is particularly preferred.
X is preferably an electron withdrawing group. Preferred electron withdrawing groups are halogen atoms, aliphatic / aryl or heterocyclic sulfonyl groups, aliphatic / aryl or heterocyclic acyl groups, aliphatic / aryl or heterocyclic oxycarbonyl groups, carbamoyl groups, sulfamoyl groups, More preferred are a halogen atom and a carbamoyl group, and particularly preferred is a bromine atom.
Z ₁ and Z ₂ are preferably a bromine atom or an iodine atom, and more preferably a bromine atom.
Y preferably represents -C (= O) -, - SO -, - SO 2 -, - C (= O) N (R) -, - SO 2 N (R) - , more preferably -C ( ═O) —, —SO ₂ —, —C (═O) N (R) —, and particularly preferably —SO ₂ —, —C (═O) N (R) —. R here represents a hydrogen atom, an aryl group or an alkyl group, more preferably a hydrogen atom or an alkyl group, and particularly preferably a hydrogen atom.
n represents 0 or 1, and is preferably 1.
In the general formula (H), when Q is an alkyl group, preferred Y is —C (═O) N (R) —, and when Q is an aryl group or heterocyclic group, preferred Y is —SO ₂ —. is there.
In the general formula (H), a form in which residues obtained by removing a hydrogen atom from the compound are bonded to each other (generally referred to as bis type, tris type, tetrakis type) can also be preferably used.
In the general formula (H), a dissociable group (for example, a COOH group or a salt thereof, a SO ₃ H group or a salt thereof, a PO ₃ H group or a salt thereof), a group containing a quaternary nitrogen cation (for example, an ammonium group or a pyridinium group) Etc.), those having a polyethyleneoxy group, a hydroxyl group or the like as a substituent are also preferred forms.

  Specific examples of the compound represented by formula (H) in the present invention are shown below.

As polyhalogen compounds that can be used in the present invention other than the above, US Pat. No. 3,874,946, US Pat. No. 4,756,999, US Pat. No. 5,340,712, US Pat. 119624, 59-57234, JP-A-7-2781, 7-5621, 9-160164, 9-244177, 9-244178, 9-160167, 9- 319022, 9-258367, 9-265150, 9-319022, 10-197988, 10-197989, 11-242304, JP 2000-2963, JP 2000-11270 , JP2000-284410, JP2 The compounds listed as exemplary compounds of the invention in 00-284212, JP-A-2001-33911, JP-A-2001-31644, JP-A-2001-312027, and JP-A-2003-50441 are preferably used. In particular, compounds specifically exemplified in JP-A-7-2781, JP-A-2001-33911, and JP-A-2001-312027 are preferred.
The compound represented by formula (H) in the present invention is preferably used in the range of 10 ⁻⁴ mol to 1 mol, more preferably 10 ⁻³ , per mol of the non-photosensitive silver salt in the image forming layer. It is preferable to use in the range of from 1 to 10 mol, more preferably from 1 × 10 ⁻² mol to 0.2 mol.
In the present invention, the antifoggant is added to the light-sensitive material by the method described in the method for containing a reducing agent, and the organic polyhalogen compound is also preferably added as a solid fine particle dispersion.

(Other antifoggants)
Examples of other antifoggants include mercury (II) salts described in JP-A No. 11-65021, paragraph number 0113, benzoic acids of paragraph No. 0114, salicylic acid derivatives disclosed in JP-A No. 2000-206642, and formulas described in JP-A No. 2000-221634. A formalin scavenger compound represented by (S), a triazine compound according to claim 9 of JP-A-11-352624, a compound represented by formula (III) of JP-A-6-11791, 4-hydroxy-6-6 And methyl-1,3,3a, 7-tetrazaindene and the like.

The photothermographic material in the invention may contain an azolium salt for the purpose of fog prevention. Examples of the azolium salt include compounds represented by general formula (XI) described in JP-A-59-193447, compounds described in JP-B-55-12581, and general formula (II) described in JP-A-60-153039. And the compounds represented. The azolium salt may be added to any part of the light-sensitive material, but the addition layer is preferably added to the layer having the image forming layer, and more preferably added to the image forming layer. The azolium salt may be added at any step during the preparation of the coating solution, and when added to the image forming layer, any step from the preparation of the organic silver salt to the preparation of the coating solution may be used. Immediately before is preferable. The azolium salt may be added by any method such as powder, solution, fine particle dispersion. Moreover, you may add as a solution mixed with other additives, such as a sensitizing dye, a reducing agent, and a color toning agent. In the present invention, the azolium salt may be added in any amount, but it is 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.

(Other additives)
1) Mercapto, disulfide, and thiones In the present invention, mercapto compounds and disulfide compounds are used for the purpose of controlling development by suppressing or promoting development, improving spectral sensitization efficiency, and improving storage stability before and after development. And thione compounds, paragraphs 0067 to 0069 of JP-A-10-62899, compounds represented by formula (I) of JP-A-10-186572, and specific examples thereof include paragraph numbers 0033 to 0052. , European Patent Publication No. 0803764A1, page 20, lines 36-56. Of these, mercapto-substituted heteroaromatic compounds described in JP-A-9-297367, JP-A-9-304875, JP-A-2001-100388, JP-A-2002-303955, JP-A-2002-303951, and the like are preferable. .

2) Toning agent In the photothermographic material of the invention, it is preferable to add a toning agent. For the toning agent, paragraph numbers 0054 to 0055 of JP-A-10-62899, page 21 to 23 of European Patent Publication No. 0803764A1. Line 48, described in JP-A No. 2000-356317 and JP-A No. 2000-187298, and in particular, phthalazinones (phthalazinone, phthalazinone derivatives or metal salts; for example, 4- (1-naphthyl) phthalazinone, 6-chlorophthalazinone. 5,7-dimethoxyphthalazinone and 2,3-dihydro-1,4-phthalazinedione); phthalazinones and phthalic acids (eg, phthalic acid, 4-methylphthalic acid, 4-nitrophthalic acid, diammonium phthalate) , Sodium phthalate, potassium phthalate and tetrachlorophthalic anhydride) Combinations; phthalazines (phthalazine, phthalazine derivatives or metal salts; for example, 4- (1-naphthyl) phthalazine, 6-isopropylphthalazine, 6-t-butylphthalazine, 6-chlorophthalazine, 5,7-dimethoxyphthalazine And 2,3-dihydrophthalazine); a combination of phthalazines and phthalic acids is preferable, and a combination of phthalazines and phthalic acids is particularly preferable. Among them, a particularly preferable combination is a combination of 6-isopropylphthalazine and phthalic acid or 4-methylphthalic acid.

3) Plasticizers and lubricants In the present invention, known plasticizers and lubricants can be used to improve film physical properties. In particular, it is preferable to use a lubricant such as liquid paraffin, long chain fatty acid, fatty acid amide, fatty acid ester, etc., in order to improve handling at the time of manufacture and scratch resistance at the time of heat development. In particular, liquid paraffin from which low-boiling components have been removed and fatty acid esters having a branched structure and having a molecular weight of 1000 or more are preferred.
Regarding the plasticizer and lubricant that can be used in the image forming layer and the non-photosensitive layer, JP-A No. 11-65021, paragraph No. 0117, JP-A No. 2000-5137, Japanese Patent Application No. 2003-8015, Japanese Patent Application No. 2003-8071, The compounds described in Japanese Patent Application No. 2003-132815 are preferred.

4) Dye and Pigment In the image forming layer of the present invention, various dyes and pigments (for example, CI Pigment Blue 60, CI, etc.) are used from the viewpoints of color tone improvement, prevention of interference fringes during laser exposure, and prevention of irradiation. Pigment Blue 64, CI Pigment Blue 15: 6) can be used. These are described in detail in WO98 / 36322, JP-A-10-268465, JP-A-11-338098 and the like.

5) Super-high contrast agent For the formation of a super-high contrast image suitable for printing plate making, it is preferable to add a super-high contrast agent to the image forming layer. As for the ultra-high contrast agent and its addition method and addition amount, the formula (H of JP-A No. 11-65021, paragraph No. 0118, JP-A No. 11-223898, paragraph Nos. 0136 to 0193 and JP-A No. 2000-284399 are described. ), Formulas (1) to (3), compounds of formulas (A) and (B), compounds of general formulas (III) to (V) described in Japanese Patent Application No. 11-91652 (specific compounds: 21 to 24) and the high contrast accelerator are described in paragraph No. 0102 of JP-A No. 11-65021 and paragraph Nos. 0194 to 0195 of JP-A No. 11-223898.

  In order to use formic acid or formate as a strong fogging substance, it is preferably contained in an amount of 5 mmol or less, more preferably 1 mmol or less per mol of silver on the side having an image forming layer containing photosensitive silver halide.

When the ultrahigh contrast agent is used in the photothermographic material of the present invention, it is preferable to use an acid formed by hydrating diphosphorus pentoxide or a salt thereof in combination. 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), hexametalin An acid (salt) etc. can be mentioned. Examples of the acid or salt thereof formed by hydrating diphosphorus pentoxide particularly preferably include orthophosphoric acid (salt) and hexametaphosphoric acid (salt). Specific examples of the salt include sodium orthophosphate, sodium dihydrogen orthophosphate, sodium hexametaphosphate, and ammonium hexametaphosphate.
The amount of acid or salt thereof formed by hydration of diphosphorus pentoxide (the coating amount per 1 m ^{2 of} photosensitive material) may be a desired amount according to the performance such as sensitivity and fog, but is 0.1 mg / m ^2. It is preferably 500 mg / m ² or less, more preferably 0.5 mg / m ² or more and 100 mg / m ² or less.
The reducing agent, hydrogen bonding compound, development accelerator and polyhalogen compound in the present invention are preferably used as a solid dispersion, and a preferred method for producing these solid dispersions is described in JP-A-2002-55405. .

(Preparation and application of coating solution)
The preparation temperature of the image forming layer coating solution in the invention is preferably from 30 ° C. to 65 ° C., more preferably from 35 ° C. to less than 60 ° C., and more preferably from 35 ° C. to 55 ° C. Moreover, it is preferable that the temperature of the image forming layer coating liquid immediately after the addition of the polymer latex is maintained at 30 ° C. or higher and 65 ° C. or lower.

(Other layer structures and components)
1) Surface protective layer The photothermographic material according to the invention may be provided with a surface protective layer for the purpose of preventing adhesion of the image forming layer. The surface protective layer may be a single layer or a plurality of layers.
The surface protective layer is described in JP-A No. 11-65021, paragraph numbers 0119 to 0120 and JP-A No. 2000-171936.
As the binder for the surface protective layer in the present invention, gelatin is preferable, but it is also preferable to use polyvinyl alcohol (PVA) or a combination thereof. As gelatin, inert gelatin (for example, Nitta gelatin 750), phthalated gelatin (for example, Nitta gelatin 801), and the like can be used. Examples of PVA include those described in paragraph Nos. 0009 to 0020 of JP-A No. 2000-171936. Completely saponified PVA-105, partially saponified PVA-205, PVA-335, and modified polyvinyl alcohol MP- Preferred is 203 (trade name, manufactured by Kuraray Co., Ltd.). Polyvinyl alcohol coating amount is preferably 0.3 g / m ² or more 4.0 g / m ² or less as (support 1m per ²⁾ of the protective layer (per one layer), 0.3 g / m ² or more 2.0 g / m ² or less is more preferable.

The total coating amount (including water-soluble polymer and latex polymer) of the surface protective layer (per layer) is preferably 0.3 g / m ² or more and 5.0 g / m ² or less as the coating amount (per 1 m ^{2 of the} support). .3g / m ² or more 2.0 g / m ² or less is more preferable.
In addition, it is preferable to use a lubricant such as liquid paraffin and aliphatic ester for the surface protective layer. The amount of the lubricant used is in the range of 1 mg / m ^{2 to} 200 mg / m ² , preferably 10 mg / m ^{2 to} 150 mg / m ² , more preferably 20 mg / m ^{2 to} 100 mg / m ^2. .

2) Antihalation layer In the photothermographic material of the invention, the antihalation layer can be provided on the side farther from the light source than the image forming layer.

As for the antihalation layer, paragraphs 0123 to 0124 of JP-A-11-65021, JP-A-11-223898, 9-230531, 10-36695, 10-104779, 11-231457, 11 -352625, 11-352626 and the like.
The antihalation layer contains an antihalation dye having absorption at the exposure wavelength. When the exposure wavelength is in the infrared region, an infrared absorbing dye may be used, and in that case, a dye having no absorption in the visible region is preferable.
When antihalation is performed using a dye having absorption in the visible range, it is preferable that substantially no dye color remains after image formation, and a means for decoloring by the heat of heat development is used. In particular, it is preferable to add a thermally decolorable dye and a base precursor to the non-photosensitive layer to function as an antihalation layer. These techniques are described in JP-A-11-231457 and the like.

The amount of decoloring dye added is determined by the use of the dye. In general, the optical density (absorbance) measured at the target wavelength is used in an amount exceeding 0.1. The optical density is preferably 0.15 to 2, and more preferably 0.2 to 1. The amount of dye used to obtain such an optical density is generally about 0.001 to 1 g / m ² .

When the dye is decolored in this way, the optical density after heat development can be reduced to 0.1 or less. Two or more kinds of decoloring dyes may be used in combination in a heat decoloring type recording material or a photothermographic material. Similarly, two or more kinds of base precursors may be used in combination.
In the thermal decoloration using such decoloring dye and base precursor, a substance (for example, diphenylsulfone, which lowers the melting point by 3 ° C. (deg) or more when mixed with a base precursor as described in JP-A No. 11-352626). 4-Chlorophenyl (phenyl) sulfone), 2-naphthyl benzoate and the like are preferably used in view of thermal decoloring properties.

3) Back Layer Back layers that can be applied to the present invention are described in paragraph Nos. 0128 to 0130 of JP-A No. 11-65021.

In the present invention, a colorant having an absorption maximum at 300 to 450 nm can be added for the purpose of improving the silver color tone and the temporal change of the image. Such colorants are disclosed in JP-A-62-210458, JP-A-63-104046, JP-A-63-103235, JP-A-63-208846, JP-A-63-306436, JP-A-63-141435, and JP-A-01-61745. No. 1, Japanese Patent Laid-Open No. 2001-100363, and the like.
Such a colorant is usually added in a range of 0.1 mg / m ² or more and 1 g / m ² or less, and the layer to be added is preferably a back layer provided on the opposite side of the image forming layer.
In order to adjust the base color tone, it is preferable to use a dye having an absorption peak at 580 to 680 nm. As the dye for this purpose, azomethine oil-soluble dyes described in JP-A-4-359967 and JP-A-4-359968, which have a small absorption intensity on the short wavelength side, and phthalocyanine water-soluble dyes described in Japanese Patent Application No. 2002-96797 are preferable. The target dye may be added to any layer, but is more preferably added to the non-photosensitive layer on the image forming layer surface side or the back surface side.

  The photothermographic material of the present invention is a so-called single-sided photosensitive material having an image forming layer containing at least one silver halide emulsion on one side of a support and a back layer on the other side. preferable.

4) Polymer Latex When the photothermographic material of the present invention is used for printing applications in which dimensional change is a problem, it is preferable to use a polymer latex for the surface protective layer or the back layer. For such polymer latex, “Synthetic resin emulsion (Hiraku Okuda, Hiroshi Inagaki, published by Kobunshi Publishing (1978))”, “Application of synthetic latex (Takaaki Sugimura, Ikuo Kataoka, Junichi Suzuki, Keiji Kasahara, Takashi "Molecular Publications (1993))" and "Synthetic Latex Chemistry (Muroichi Muroi, published by High Polymers Publication (1970))", specifically, methyl methacrylate (33.5% by mass) / Ethyl acrylate (50 wt%) / methacrylic acid (16.5 wt%) copolymer latex, methyl methacrylate (47.5 wt%) / butadiene (47.5 wt%) / itaconic acid (5 wt%) copolymer Latex, latex of ethyl acrylate / methacrylic acid copolymer, methyl methacrylate (58.9% by mass) / 2-ethyl Latex of xyl acrylate (25.4 mass%) / styrene (8.6 mass%) / 2-hydroxyethyl methacrylate (5.1 mass%) / acrylic acid (2.0 mass%) copolymer, methyl methacrylate (64. 0 mass%) / styrene (9.0 mass%) / butyl acrylate (20.0 mass%) / 2-hydroxyethyl methacrylate (5.0 mass%) / acrylic acid (2.0 mass%) copolymer latex, etc. Is mentioned. Furthermore, as a binder for the surface protective layer, a combination of polymer latex described in Japanese Patent Application No. 11-6872 and a technique described in Paragraph Nos. 0021 to 0025 of Japanese Patent Application Laid-Open No. 2000-267226, Japanese Patent Application No. 11-6872 The technology described in paragraph numbers 0027 to 0028 of the specification and the technology described in paragraph numbers 0023 to 0041 of JP 2000-19678 may be applied. The ratio of the polymer latex in the surface protective layer is preferably 10% by mass or more and 90% by mass or less, and particularly preferably 20% by mass or more and 80% by mass or less of the total binder.

5) Membrane surface pH
The photothermographic material of the present invention preferably has a film surface pH of 7.0 or less, more preferably 6.6 or less before heat development. The lower limit is not particularly limited, but is about 3. The most preferred pH range is in the range of 4 to 6.2. For the adjustment of the film surface pH, it is preferable to use an organic acid such as a phthalic acid derivative, a non-volatile acid such as sulfuric acid, and a volatile base such as ammonia from the viewpoint of reducing the film surface pH. In particular, ammonia is volatile and is preferable for achieving a low film surface pH because it can be removed before the coating process or heat development.
In addition, it is also preferable to use ammonia in combination with a nonvolatile base such as sodium hydroxide, potassium hydroxide, or lithium hydroxide. In addition, the measuring method of film surface pH is described in paragraph number 0123 of Unexamined-Japanese-Patent No. 2000-284399.

6) Hardener A hardener may be used for each layer such as the image forming layer, protective layer, and back layer in the present invention. Examples of hardeners include T.W. H. There are various methods described in "THE THEORY OF THE PHOTOGRAPHIC PROCESS FOURTH EDITION" written by James (published by Macmillan Publishing Co., Inc., published in 1977), pages 77 to 87. -S-triazine sodium salt, N, N-ethylenebis (vinylsulfoneacetamide), N, N-propylenebis (vinylsulfoneacetamide), polyvalent metal ions described on page 78 of the same, U.S. Pat. No. 4,281, Polyisocyanates such as 060 and JP-A-6-208193, epoxy compounds such as US Pat. No. 4,791,042, and vinyl sulfone compounds such as JP-A 62-89048 are preferably used.

  The hardening agent is added as a solution, and the addition time of this solution into the protective layer coating solution is from 180 minutes before to immediately before application, preferably from 60 minutes to 10 seconds before application. As long as the effects of the present invention are sufficiently exhibited, there is no particular limitation. Specific mixing methods include mixing in a tank in which the average residence time calculated from the addition flow rate and the amount of liquid fed to the coater is a desired time, and N.I. Harnby, M.M. F. Edwards, A.D. W. There is a method using a static mixer described in Chapter 8 of Nienow's “Liquid Mixing Technology” (Nikkan Kogyo Shimbun, 1989), translated by Koji Takahashi.

7) Surfactant As for the surfactant applicable to the present invention, paragraph No. 0132 of JP-A No. 11-65021, paragraph No. 0133 of the solvent, paragraph No. 0134 of the support, and antistatic or conductive layer Are described in paragraph No. 0135 of the same number, paragraph No. 0136 of the same number regarding the method of obtaining a color image, paragraph numbers 0061 to 0064 of JP-A No. 11-84573 and paragraph numbers 0049 to 0062 of JP-A No. 2001-83679 regarding the slip agent. ing.
In the present invention, it is preferable to use a fluorosurfactant. Specific examples of the fluorosurfactant include compounds described in JP-A Nos. 10-197985, 2000-19680, 2000-214554 and the like. Further, a polymeric fluorine-based surfactant described in JP-A-9-281636 is also preferably used. In the photothermographic material of the present invention, it is preferable to use a fluorosurfactant described in JP-A Nos. 2002-82411, 2003-057780, and Japanese Patent Application No. 2001-264110. In particular, the fluorosurfactants described in JP-A No. 2003-057780 and Japanese Patent Application No. 2001-264110 are preferable in terms of charge adjustment ability, stability of the coated surface, and smoothness when coating and production is performed with an aqueous coating solution. The fluorine-based surfactant described in Japanese Patent Application No. 2002-074564 is most preferable in that it has a high charge adjusting ability and requires a small amount of use.
In the present invention, the fluorosurfactant can be used on either the image forming layer surface or the back surface, and is preferably used on both surfaces. Further, it is particularly preferable to use in combination with a conductive layer containing the above-described metal oxide. In this case, sufficient performance can be obtained even if the amount of the fluorosurfactant used on the surface having the conductive layer is reduced or removed.
The preferred amount of the fluorocarbon surfactant is an image forming layer side, the range to the back surface each ^{0.1mg / m 2 ~100mg / m 2} , more preferably 0.3mg / m ² ~30mg / m ² range, even more preferably from ^{1mg / m 2 ~10mg / m 2} . Especially, the fluorocarbon surfactant described in Japanese Patent Application No. 2001-264110 is effective, and preferably in the range of 0.01 to 10 mg / m ^2, the range of 0.1 to 5 mg / m ² is more preferable.

8) Antistatic agent In this invention, it is preferable to have a conductive layer containing a metal oxide or a conductive polymer. The antistatic layer may serve as an undercoat layer, a back layer surface protective layer, or the like, or may be provided separately. As the conductive material for the antistatic layer, a metal oxide in which conductivity is improved by introducing oxygen defects or different metal atoms into the metal oxide is preferably used. Examples of metal oxides are preferably ZnO, TiO ₂ and SnO _2. Addition of Al and In to ZnO, addition of Sb, Nb, P and halogen elements to SnO ₂ , and addition to TiO _2. For example, addition of Nb, Ta or the like is preferable. In particular, SnO ₂ added with Sb is preferable. The amount of different atoms added is preferably in the range of 0.01 to 30 mol%, more preferably in the range of 0.1 to 10 mol%. The shape of the metal oxide may be spherical, needle-like, or plate-like, but the long axis / uniaxial ratio is 2.0 or more, preferably 3.0 to 50 in terms of the effect of imparting conductivity. Good. Range amount preferably of 1mg / m ² ~1000mg / m ² of metal oxide, more preferably 10mg / m ² ~500mg / m ² range, more preferably at 20mg / m ² ~200mg / m ² It is a range. The antistatic layer in the present invention may be disposed on either the image forming layer surface side or the back surface side, but is preferably disposed between the support and the back layer. Specific examples of the antistatic layer include those described in paragraph No. 0135 of JP-A No. 11-65021, JP-A Nos. 56-143430, 56-143431, 58-62646, No. 56-120519, and JP-A No. 11-84573. Paragraph Nos. 0040 to 0051, US Pat. No. 5,575,957, and paragraph Nos. 0078 to 0084 of JP-A-11-223898.

9) Support The transparent support was subjected to a heat treatment in a temperature range of 130 to 185 ° C. in order to relieve internal strain remaining in the film during biaxial stretching and to eliminate heat shrinkage strain generated during heat development processing. Polyester, particularly polyethylene terephthalate is preferably used. In the case of a photothermographic material for medical use, the transparent support may be colored with a blue dye (for example, dye-1 described in Examples of JP-A-8-240877) or may be uncolored. Examples of the support include water-soluble polyesters disclosed in JP-A-11-84574, styrene-butadiene copolymers described in JP-A-10-186565, and vinylidene chloride described in JP-A-2000-39684 and Japanese Patent Application No. 11-106881, paragraphs 0063-0080. It is preferable to apply an undercoating technique such as a copolymer. When the image forming layer or the back layer is applied to the support, the water content of the support is preferably 0.5 wt% or less.

10) Other additives The photothermographic material may further contain an antioxidant, a stabilizer, a plasticizer, an ultraviolet absorber or a coating aid. Various additives are added to either the image forming layer or the non-photosensitive layer. With respect to these, WO 98/36322, EP 803764A1, JP-A-10-186567, 10-18568 and the like can be referred to.

11) Coating method The photothermographic material in the invention may be coated by any method. Specifically, various coating operations including extrusion coating, slide coating, curtain coating, dip coating, knife coating, flow coating, or extrusion coating using a hopper of the type described in US Pat. No. 2,681,294. And Stephen F. Kistler, Peter M. et al. Extrusion coating or slide coating described in pages 399 to 536 of “LIQUID FILM COATING” (CHAPMAN & HALL, 1997) by Schweizer is preferably used, and slide coating is particularly preferably used. An example of the shape of a slide coater used for slide coating is shown in FIG. 11b. 1 If desired, two or more layers can be coated simultaneously by the method described on pages 399 to 536 of the same document, the method described in US Pat. No. 2,761,791 and British Patent No. 837,095. . In the present invention, particularly preferred coating methods are those described in JP-A Nos. 2001-194748, 2002-153808, 2002-153803, and 2002-182333.

The image forming layer coating solution in the present invention is preferably a so-called thixotropic fluid. Regarding this technique, JP-A-11-52509 can be referred to. In the image forming layer coating solution of the present invention, the viscosity at a shear rate of 0.1 S ⁻¹ is preferably 400 mPa · s or more and 100,000 mPa · s or less, more preferably 500 mPa · s or more and 20,000 mPa · s or less. Further, at a shear rate of 1000 S ⁻¹ , 1 mPa · s to 200 mPa · s is preferable, and 5 mPa · s to 80 mPa · s is more preferable.

In the case of preparing a coating liquid, a known in-line mixer or implant mixer is preferably used when mixing two kinds of liquids. A preferable in-line mixer in the present invention is described in JP-A No. 2002-85948, and an implant mixer is described in JP-A No. 2002-90940.
The coating solution in the present invention is preferably subjected to defoaming treatment in order to keep the coated surface state good. A preferable defoaming treatment method in the present invention is the method described in JP-A No. 2002-66431.
When applying the coating solution, it is preferable to perform static elimination in order to prevent adhesion of dust, dust, and the like due to electric resistance of the support. An example of a preferable static elimination method in the present invention is described in JP-A No. 2002-143747.
In the present invention, it is important to precisely control the drying air and the drying temperature in order to dry the non-setting image forming layer coating solution. Preferred drying methods in the present invention are described in detail in JP-A Nos. 2001-194749 and 2002-139814.
The photothermographic material of the present invention is preferably subjected to a heat treatment immediately after coating and drying in order to improve film formability. The temperature of the heat treatment is preferably in the range of 60 ° C. to 100 ° C. as the film surface temperature, and the heating time is preferably in the range of 1 second to 60 seconds. A more preferable range is a film surface temperature of 70 to 90 ° C. and a heating time of 2 to 10 seconds. A preferable heat treatment method in the present invention is described in JP-A No. 2002-107872.
In order to stably and continuously produce the photothermographic material of the present invention, the production methods described in JP-A Nos. 2002-156728 and 2002-182333 are preferably used.

  The photothermographic material is preferably a mono-sheet type (a type capable of forming an image on the photothermographic material without using another sheet such as an image receiving material).

12) Packaging material The photosensitive material of the present invention is packaged with a packaging material having a low oxygen permeability and / or moisture permeability in order to suppress fluctuations in photographic performance during raw storage or to improve curling, curling, etc. It is preferable. The oxygen permeability is preferably 50 ml / atm · m ² · day or less at 25 ° C., more preferably 10 ml / atm · m ² · day or less, more preferably 1.0 ml / atm · m ² · day or less. is there. The moisture permeability is preferably 10 g / atm · m ² · day or less, more preferably 5 g / atm · m ² · day or less, and still more preferably 1 g / atm · m ² · day or less.
Specific examples of the packaging material having low oxygen permeability and / or moisture permeability are disclosed in, for example, JP-A-8-254793. This is a packaging material described in JP-A-2000-206653.

13) Other technologies that can be used Techniques that can be used in the photothermographic material of the present invention include EP80364A1, EP883022A1, WO98 / 36322, JP-A-56-62648, JP-A-58-62644, and JP-A-5-62644. 9-43766, 9-281737, 9-297367, 9-304869, 9-31405, 9-329865, 10-10669, 10-62899, 10-69023 10-186568, 10-90823, 10-171603, 10-186565, 10-186567, 10-186567 to 10-186572, 10-197974, Nos. 10-197982, 10-197983, 10-197985 to 1 No. 0-197987, No. 10-207001, No. 10-207004, No. 10-221807, No. 10-282601, No. 10-288823, No. 10-288824, No. 10-307365, No. 10- No. 312038, No. 10-339934, No. 11-7100, No. 11-15105, No. 11-24200, No. 11-24201, No. 11-30832, No. 11-84574, No. 11-65021 11-109547, 11-125880, 11-129629, 11-133536 to 11-133539, 11-133542, 11-133543, 11-223898, 11-352627, 11-305377, 11-305378, 11-305 84, 11-305380, 11-316435, 11-327076, 11-338096, 11-338098, 11-338099, 11-343420, 2001-200414 2001-234635, 2002-020699, 2001-275471, 2001-275461, 2000-313204, 2001-292844, 2000-324888, 2001-293864, 2001-348546 and 2000-187298 are also mentioned.

In the case of multicolor color photothermographic materials, each image-forming layer is generally a functional or non-functional barrier between each photosensitive layer as described in US Pat. No. 4,460,681. By using layers, they are kept distinct from each other.
The construction in the case of a multicolor color photothermographic material may include a combination of these two layers for each color and all within a single layer as described in US Pat. No. 4,708,928. Ingredients may be included.

3. Image Forming Method 1) Exposure Red to infrared emission He—Ne laser, red semiconductor laser, blue to green emission Ar ⁺ , He—Ne, He—Cd laser, blue semiconductor laser. Preferred is a red to infrared semiconductor laser, and the peak wavelength of the laser light is 600 nm to 900 nm, preferably 620 nm to 850 nm.
On the other hand, in recent years, in particular, a module in which an SHG (Second Harmonic Generator) element and a semiconductor laser are integrated and a blue semiconductor laser have been developed, and a laser output device in a short wavelength region has been closed up. The blue semiconductor laser is expected to increase in demand in the future because high-definition image recording is possible, the recording density is increased, and a stable output is obtained with a long lifetime. The peak wavelength of the blue laser light is preferably 300 nm to 500 nm, particularly preferably 400 nm to 500 nm.
It is also preferable that the laser light is oscillated in a vertical multi by a method such as high frequency superposition.

2) Photothermographic development The photothermographic material of the present invention may be developed by any method, but is usually developed by raising the temperature of the photothermographic material exposed imagewise. The development temperature is preferably 80 ° C. or higher and 250 ° C. or lower, preferably 100 ° C. or higher and 140 ° C. or lower, more preferably 110 ° C. or higher and 130 ° C. or lower. The development time is preferably from 1 second to 60 seconds, more preferably from 3 seconds to 30 seconds, still more preferably from 5 seconds to 25 seconds, and particularly preferably from 7 seconds to 15 seconds.

In the present invention, it is possible to employ a system in which the heating section is fixed and the photothermographic material is heated while sliding. Either a drum type heater or a plate type heater may be used as the thermal development method, but the plate type heater method is more preferable. In the thermal development method using a plate heater method, development is performed while sliding the photosensitive material. Among the plate-type heater systems, the method described in JP-A-11-133572 is preferable. The thermal development apparatus described herein is a thermal development apparatus that obtains a visible image by bringing a photothermographic material having a latent image formed thereon into contact with a heating unit in a thermal development unit, wherein the heating unit is a plate heater. And a plurality of pressing rollers are arranged to face each other along one surface of the plate heater, and the photothermographic material is passed between the pressing roller and the plate heater to perform heat development. The heat developing apparatus is characterized.
It is preferable to divide the plate heater into 2 to 6 stages and lower the temperature about 1 to 10 ° C. at the tip. For example, there are examples in which four sets of plate heaters that can be independently controlled are used and controlled so as to be 112 ° C., 119 ° C., 121 ° C., and 120 ° C., respectively. Such a method is also described in JP-A-54-30032, which can exclude moisture and organic solvents contained in the photothermographic material out of the system, and rapidly develop the photothermographic material. It is also possible to suppress a change in the shape of the support of the photothermographic material due to the heating.

  In order to reduce the size of the heat developing machine and shorten the heat development time, it is preferable to be able to control the heater more stably. In addition, the exposure of one sheet of photosensitive material is started from the top and the exposure is finished to the back end. It is desirable to start the heat development before the time. Imagers capable of rapid processing preferable for the present invention are described in, for example, JP-A Nos. 2002-289804 and 2002-287668. If this imager is used, for example, heat development can be performed in 14 seconds with a three-stage plate heater controlled at 107 ° C.-121 ° C.-121 ° C., and the output time of the first sheet is reduced to about 60 seconds. be able to. For such rapid development processing, it is preferable to use the photothermographic material-2 of the present invention in combination with high sensitivity and less susceptible to environmental temperature.

  Since the photothermographic material of the present invention is extremely excellent in transportability, an image quality excellent in graininess and scratch resistance can be provided even if the transport speed of the photosensitive material during development is 10 mm / second or more. The same effect can be obtained even when the conveyance speed during development is 15 mm / second or more.

3) System As a medical laser imager provided with an exposure part and a heat development part, Fuji Medical Dry Laser Imager FM-DPL and DRYPIX7000 can be exemplified. Regarding FM-DPL, Fuji Medical Review No. 8, pages 39 to 55, and it goes without saying that those techniques are applied as a laser imager of the photothermographic material of the present invention. Further, it can also be applied as a photothermographic material for a laser imager in “AD network” proposed by Fuji Film Medical Co., Ltd. as a network system adapted to the DICOM standard.

4). Use of the Invention The photothermographic material of the invention forms a black-and-white image by a silver image, and is used for medical diagnosis, photothermographic material for industrial photography, photothermographic material for printing, heat for COM. It is preferably used as a developing photosensitive material.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples.

(Preparation of PET support)
1) Film formation Using terephthalic acid and ethylene glycol, PET having an intrinsic viscosity of IV = 0.66 (measured in phenol / tetrachloroethane = 6/4 (weight ratio) at 25 ° C.) is obtained. It was. This was pelletized, dried at 130 ° C. for 4 hours, melted at 300 ° C., extruded from a T-die, and rapidly cooled to prepare an unstretched film.

This was longitudinally stretched 3.3 times using rolls with different peripheral speeds, and then stretched 4.5 times with a tenter. The temperatures at this time were 110 ° C. and 130 ° C., respectively. Thereafter, the film was heat-fixed at 240 ° C. for 20 seconds and relaxed by 4% in the lateral direction at the same temperature. Thereafter, the chuck portion of the tenter was slit and then knurled at both ends, and wound at 4 kg / cm ² to obtain a roll having a thickness of 175 μm.

2) Surface corona treatment Both surfaces of the support were treated at room temperature at 20 m / min using a solid state corona treatment machine 6KVA model manufactured by Pillar. From the current and voltage readings at this time, it was found that the support was processed at 0.375 kV · A · min / m ² . The treatment frequency at this time was 9.6 kHz, and the gap clearance between the electrode and the dielectric roll was 1.6 mm.

3) Undercoat 1) Preparation formulation of undercoat layer coating solution (1) (for image forming layer side undercoat layer)
・ Pesresin A-520 (30% by mass solution) manufactured by Takamatsu Yushi Co., Ltd. 46.8 g
・ Toyobo Co., Ltd. Bironal MD-1200 10.4 g
Polyethylene glycol monononyl phenyl ether (average ethylene oxide number = 8.5) 1% by weight solution 11.0 g
・ MP-1000 (PMMA polymer fine particles, average particle size 0.4 μm) 0.91 g manufactured by Soken Chemical Co., Ltd.
・ 931 ml of distilled water

Formula (2) (for back layer 1st layer)
・ Styrene-butadiene copolymer latex 130.8 g
(Solid content 40% by mass, styrene / butadiene weight ratio = 68/32)
2,4-Dichloro-6-hydroxy-S-triazine sodium salt
8% by weight aqueous solution 5.2g
・ 10% 1% by weight aqueous solution of sodium laurylbenzenesulfonate
・ Polystyrene particle dispersion (average particle size 2 μm, 20 mass%) 0.5 g
-854 ml of distilled water

Formula (3) (for back side second layer)
SnO ₂ / SbO (9/1 mass ratio, average particle size 0.5 μm, 17 mass% dispersion) 84 g
・ Gelatin 7.9g
・ Shin-Etsu Chemical Co., Ltd. Metros TC-5 (2 mass% aqueous solution) 10g
・ 10% 1% aqueous solution of sodium dodecylbenzenesulfonate
・ NaOH (1% by mass) 7 g
・ Proxel (Abyssia) 0.5g
・ Distilled water 881ml

After both surfaces of the biaxially stretched polyethylene terephthalate support having a thickness of 175 μm are subjected to the corona discharge treatment, the undercoat coating solution formulation (1) is applied on one side (image forming layer surface) with a wire bar with a wet coating amount of 6. .6ml / m ² was applied (per one side) and dried for 5 minutes at 180 ° C., then the amount of wet coating the coating solution for the undercoat was coated (2) by a wire bar on the rear surface (back surface) 5. Apply to 7 ml / m ² , dry at 180 ° C. for 5 minutes, and further wet coat amount of 8.4 ml / m ² with the above-mentioned undercoat coating liquid formulation (3) on the back surface (back surface) with a wire bar. It was applied as described above and dried at 180 ° C. for 6 minutes to prepare an undercoat support.

(Back layer)
1) Preparation of back layer coating solution (preparation of solid fine particle dispersion (a) of base precursor)
Add 2.5 kg of Base Precursor Compound 1 and 300 g of a surfactant (trade name: Demol N, manufactured by Kao Corporation), 800 g of diphenylsulfone, 1.0 g of benzoisothiazolinone sodium salt and distilled water to make a total amount. The mixture was mixed to 8.0 kg, and the mixed solution was dispersed with beads using a horizontal sand mill (UVM-2: manufactured by Imex Corporation). In the dispersion method, the mixed solution was fed to UVM-2 filled with zirconia beads having an average diameter of 0.5 mm by a diaphragm pump, and dispersed at an internal pressure of 50 hPa or more until a desired average particle size was obtained.
The dispersion was subjected to spectral absorption measurement, and the ratio of absorbance at 450 nm to absorbance at 650 nm (D450 / D650) in the spectral absorption of the dispersion was dispersed to 3.0. The obtained dispersion was diluted with distilled water so that the concentration of the base precursor was 25% by weight, and was filtered for removal of dust (polypropylene filter having an average pore size of 3 μm) for practical use.

2) Preparation of Dye Solid Fine Particle Dispersion 6.0 kg of cyanine dye compound-1 and 3.0 kg of sodium p-dodecylbenzenesulfonate, 0.6 kg of surfactant Demol SNB manufactured by Kao Corporation, and antifoaming agent (product) Name: Surfynol 104E, manufactured by Nissin Chemical Co., Ltd.) 0.15 kg was mixed with distilled water to make a total liquid volume of 60 kg. The mixed solution was dispersed with 0.5 mm zirconia beads using a horizontal sand mill (UVM-2: manufactured by Imex Corporation).
The dispersion was subjected to spectral absorption measurement and dispersed until the ratio of the absorbance at 650 nm to the absorbance at 750 nm (D650 / D750) in the spectral absorption of the dispersion was 5.0 or more. The obtained dispersion was diluted with distilled water so that the concentration of the cyanine dye was 6% by mass, and was subjected to filter filtration (average pore diameter: 1 μm) for dust removal, and was put to practical use.

3) Preparation of antihalation layer coating solution Keep container at 40 ° C., gelatin 40 g, monodisperse polymethyl methacrylate fine particles (average particle size 8 μm, particle size standard deviation 0.4) 20 g, benzoisothiazolinone 0.1 g, 490 ml of water was added to dissolve the gelatin. Further, 2.3 ml of 1 mol / l sodium hydroxide aqueous solution, 40 g of the above dye solid fine particle dispersion, 90 g of the solid fine particle dispersion (a) of the above base precursor, 12 ml of 3% by weight aqueous solution of sodium polystyrenesulfonate, 10 mass of SBR latex % Liquid 180 g was mixed. Immediately before coating, 80 ml of a 4% by weight aqueous solution of N, N-ethylenebis (vinylsulfonacetamide) was mixed to prepare a coating solution for preventing halation.

4) Preparation of back surface protective layer coating solution The container was kept at 40 ° C., and gelatin was dissolved by adding 40 g of gelatin, 35 mg of benzoisothiazolinone and 840 ml of water. Further, 5.8 ml of 1 mol / l sodium hydroxide aqueous solution, 5 g of 10% by weight emulsion of liquid paraffin, 5 g of 10% by weight emulsion of trimethylolpropane triisostearate, di (2-ethylhexyl) sodium sulfosuccinate 5 10 ml of a mass% aqueous solution, 20 ml of a 3 mass% aqueous solution of sodium polystyrene sulfonate, 2.4 ml of a 2 mass% solution of a fluorosurfactant (F-1), and 2 of a 2 mass% solution of a fluorosurfactant (F-2) .4 ml of methyl methacrylate / styrene / butyl acrylate / hydroxyethyl methacrylate / acrylic acid copolymer (copolymerization weight ratio 57/8/28/5/2) latex 19% by mass 32 g was mixed. Immediately before coating, 25 ml of a 4% by weight aqueous solution of N, N-ethylenebis (vinylsulfonacetamide) was mixed to prepare a coating solution for the back surface protective layer.

5) Application of back layer On the back surface side of the undercoat support, the coating amount of the antihalation layer coating solution is 0.52 g / m ^2, and the coating amount of the back surface protective layer coating solution is 1 A simultaneous multilayer coating was applied so as to be 0.7 g / m ² , followed by drying to prepare a back layer.

(Image forming layer, intermediate layer, and surface protective layer)
1. Preparation of coating materials 1) Silver halide emulsion << Preparation of silver halide emulsion 1 >>
To a solution of 1421 ml of distilled water, 3.1 ml of a 1% by mass potassium bromide solution was added, and a solution containing 3.5 ml of 0.5 mol / L sulfuric acid and 31.7 g of phthalated gelatin was stirred in a stainless steel reaction vessel. While maintaining the liquid temperature at 30 ° C., the solution A diluted with 95.4 ml of distilled water added to 22.22 g of silver nitrate, 15.3 g of potassium bromide and 0.8 g of potassium iodide in a distilled water volume of 97.4 ml. The whole amount of the solution B diluted to 1 was added at a constant flow rate over 45 seconds. Thereafter, 10 ml of a 3.5% by mass aqueous hydrogen peroxide solution was added, and 10.8 ml of a 10% by mass aqueous solution of benzimidazole was further added. Further, a solution C in which distilled water was added to 51.86 g of silver nitrate to be diluted to 317.5 ml, a solution D in which 44.2 g of potassium bromide and 2.2 g of potassium iodide were diluted with distilled water to a volume of 400 ml was added to solution C. Was added at a constant flow rate over 20 minutes, and solution D was added by the controlled double jet method while maintaining pAg at 8.1. The total amount of potassium hexachloroiridium (III) was added 10 minutes after the start of the addition of the solution C and the solution D so as to be 1 × 10 ⁻⁴ mol per mol of silver. Further, 5 seconds after the completion of the addition of the solution C, an aqueous solution of potassium iron (II) hexacyanide was added in an amount of 3 × 10 ⁻⁴ mol per mol of silver. The pH was adjusted to 3.8 using 0.5 mol / L sulfuric acid, stirring was stopped, and a precipitation / desalting / water washing step was performed. The pH was adjusted to 5.9 with 1 mol / L sodium hydroxide to prepare a silver halide dispersion having a pAg of 8.0.

The silver halide dispersion was maintained at 38 ° C. with stirring, 5 ml of a 0.34 mass% 1,2-benzisothiazolin-3-one methanol solution was added, and the temperature was raised to 47 ° C. after 40 minutes. 20 minutes after the temperature increase, sodium benzenethiosulfonate was added in a methanol solution to 7.6 × 10 ⁻⁵ moles per 1 mole of silver, and 5 minutes later, tellurium sensitizer C was added in a methanol solution at a rate of 2. per mol of silver. 9 × 10 ⁻⁴ mol was added and aged for 91 minutes. Thereafter, a methanol solution having a molar ratio of the spectral sensitizing dye A and the sensitizing dye B of 3: 1 was added in a total amount of 1.2 × 10 ⁻³ moles of the sensitizing dyes A and B per mole of silver. , N'-dihydroxy-N "-diethylmelamine in 1.3 ml of a 0.8 wt% methanol solution was added, and after another 4 minutes, 5-methyl-2-mercaptobenzimidazole was added to the methanol solution at a rate of 4.8 per mole of silver. × 10 ⁻³ mol, 1-phenyl-2-heptyl-5-mercapto-1,3,4-triazole in methanol solution is 5.4 × 10 ⁻³ mol and 1- (3-methyl) with respect to 1 mol of silver. A silver halide emulsion 1 was prepared by adding 8.5 × 10 ⁻³ mol of ureidophenyl) -5-mercaptotetrazole in an aqueous solution to 1 mol of silver.

  The grains in the prepared silver halide emulsion were silver iodobromide grains containing 3.5 mol% of iodine having an average sphere equivalent diameter of 0.042 μm and a sphere equivalent diameter variation coefficient of 20%. The particle size and the like were determined from an average of 1000 particles using an electron microscope. The {100} face ratio of the particles was determined to be 80% using the Kubelka-Munk method.

<< Preparation of silver halide emulsion 2 >>
In the preparation of silver halide emulsion 1, the liquid temperature at the time of grain formation was changed from 30 ° C. to 47 ° C., and solution B was changed to diluting 15.9 g of potassium bromide with distilled water to a volume of 97.4 ml, Solution D was changed to diluting 45.8 g of potassium bromide with distilled water to a volume of 400 ml, and the addition time of solution C was changed to 30 minutes to remove potassium hexacyanoiron (II) in the same manner. A silver halide emulsion 2 was prepared. Precipitation / desalting / washing / dispersion was carried out in the same manner as silver halide emulsion 1. Furthermore, the addition amount of tellurium sensitizer C is 1.1 × 10 ⁻⁴ mol per mol of silver, and the addition amount of methanol solution of 3: 1 in the molar ratio of spectral sensitizing dye A and spectral sensitizing dye B is silver. The total of sensitizing dye A and sensitizing dye B per mole is 7.0 × 10 ⁻⁴ mol, and 1-phenyl-2-heptyl-5-mercapto-1,3,4-triazole is added to 1 mol of silver. Same as Emulsion 1 except that 3.3 × 10 ⁻³ mol and 1- (3-methylureidophenyl) -5-mercaptotetrazole were changed to 4.7 × 10 ⁻³ mol added to 1 mol of silver. Spectral sensitization, chemical sensitization, and addition of 5-methyl-2-mercaptobenzimidazole and 1-phenyl-2-heptyl-5-mercapto-1,3,4-triazole were performed to obtain silver halide emulsion 2. . The emulsion grains of the silver halide emulsion 2 were pure silver bromide cubic grains having an average sphere equivalent diameter of 0.080 μm and a sphere equivalent diameter variation coefficient of 20%.

<< Preparation of silver halide emulsion 3 >>
In the preparation of silver halide emulsion 1, silver halide emulsion 3 was prepared in the same manner except that the liquid temperature at the time of grain formation was changed from 30 ° C. to 27 ° C. Further, precipitation / desalting / washing / dispersion was performed in the same manner as silver halide emulsion 1. The molar ratio of spectral sensitizing dye A and spectral sensitizing dye B is 1: 1 as a solid dispersion (gelatin aqueous solution), and the addition amount is 6 × 10 ⁻ as the total of sensitizing dye A and sensitizing dye B per mole of silver. ³ mol, the amount of tellurium sensitizer C added was changed to 5.2 × 10 ⁻⁴ mol per mol of silver, and 3 minutes after the addition of tellurium sensitizer, bromoauric acid was changed to 5 × 10 ⁻⁴ per mol of silver. A silver halide emulsion 3 was obtained in the same manner as Emulsion 1 except that 2 × 10 ⁻³ mol of mol and potassium thiocyanate were added per mol of silver. The emulsion grains of the silver halide emulsion 3 were silver iodobromide grains containing 3.5 mol% of iodine having an average sphere equivalent diameter of 0.034 μm and a sphere equivalent diameter variation coefficient of 20%.

<< Preparation of mixed emulsion A for coating solution >>
70% by weight of silver halide emulsion 1, 15% by weight of silver halide emulsion 2 and 15% by weight of silver halide emulsion 3 were dissolved, and benzothiazolium iodide was dissolved in a 1% by weight aqueous solution of 7% per mole of silver. × 10 ^-3 mol was added.
Further, the amount of the one-electron oxidant produced by one-electron oxidation is 2 × 10 ⁻³ moles per mole of silver halide, each of compounds 1, 2, and 3 capable of emitting one electron or more. Added.
The adsorbing redox compounds 1 and 2 having an adsorbing group and a reducing group were added in an amount of 5 × 10 ⁻³ mol per mol of silver halide.
Further, water was added so that the content of silver halide per 1 kg of the mixed emulsion for coating solution was 38.2 g as silver. 1- (3-Methylureidophenyl) -5-mercaptotetrazole was added so as to be 0.34 g per kg of the mixed emulsion for coating solution.

2) Preparation of fatty acid silver dispersion << Preparation of fatty acid silver dispersion A >>
Henkel behenic acid (product name Edenor C22-85R) 87.6 kg, distilled water 423 L, 5 mol / L NaOH aqueous solution 49.2 L, t-butyl alcohol 120 L were mixed, and the reaction was stirred at 75 ° C. for 1 hour. To obtain sodium behenate solution A. Separately, 206.2 L (pH 4.0) of an aqueous solution containing 40.4 kg of silver nitrate was prepared and kept warm at 10 ° C. A reaction vessel containing 635 L of distilled water and 30 L of t-butyl alcohol was kept at 30 ° C., and with sufficient stirring, the total amount of the previous sodium behenate solution A and the total amount of silver nitrate aqueous solution were kept at a constant flow rate for 93 minutes 15 Added over seconds and 90 minutes. At this time, only the aqueous silver nitrate solution is added for 11 minutes after the start of the addition of the aqueous silver nitrate solution, and then the addition of the sodium behenate solution A is started. After the addition of the aqueous silver nitrate solution is completed, only the sodium behenate solution A is added for 14 minutes and 15 seconds. Was added. At this time, the temperature in the reaction vessel was 30 ° C., and the external temperature was controlled so that the liquid temperature was constant. The pipe of the addition system of the sodium behenate solution A was prepared by keeping warm water by circulating hot water outside the double pipe so that the liquid temperature at the outlet of the addition nozzle tip was 75 ° C. Moreover, the piping of the addition system of the silver nitrate aqueous solution was kept warm by circulating cold water outside the double pipe. The addition position of the sodium behenate solution A and the addition position of the aqueous silver nitrate solution were arranged symmetrically around the stirring axis, and were adjusted so as not to contact the reaction solution.

  After completion of the addition of sodium behenate solution A, the mixture was left stirring for 20 minutes at the same temperature, heated to 35 ° C. over 30 minutes, and then aged for 210 minutes. Immediately after completion of aging, the solid content was separated by centrifugal filtration, and the solid content was washed with water until the conductivity of filtered water reached 30 μS / cm. Thus, a fatty acid silver salt was obtained. The obtained solid content was stored as a wet cake without drying.

  When the morphology of the obtained silver behenate particles was evaluated by electron microscope photography, the average values were a = 0.14 μm, b = 0.4 μm, c = 0.6 μm, average aspect ratio 5.2, average sphere equivalent diameter. It was a flake-like crystal having a variation coefficient of 15% for a sphere equivalent diameter of 0.52 μm. (A, b, and c are the text provisions)

  19.3 kg of polyvinyl alcohol (trade name: PVA-217) and water are added to a wet cake corresponding to a dry solid content of 260 kg to make a total amount of 1000 kg, and then slurried with a dissolver blade, and a pipeline mixer (manufactured by Mizuho Kogyo) : PM-10 type).

Next, the pre-dispersed stock solution is adjusted to 1260 kg / cm ² by adjusting the pressure of the disperser (trade name: Microfluidizer M-610, manufactured by Microfluidics International Corporation, using Z-type interaction chamber) three times. Treatment gave a silver behenate dispersion. The cooling operation was carried out by installing a serpentine heat exchanger before and after the interaction chamber, and adjusting the temperature of the refrigerant to a dispersion temperature of 18 ° C.

<< Preparation of fatty acid silver dispersion B >>
<Preparation of recrystallized behenic acid>
100 kg of behenic acid (product name Edenor C22-85R) manufactured by Henkel was mixed in 1200 kg of isopropyl alcohol, dissolved at 50 ° C., filtered through a 10 μm filter, cooled to 30 ° C., and recrystallized. The cooling speed during recrystallization was controlled at 3 ° C./hour. The obtained crystals were centrifugally filtered, washed with 100 kg of isopropyl alcohol, and then dried. When the obtained crystals were esterified and subjected to GC-FID measurement, the behenic acid content was 96 mol%, and in addition, lignoceric acid was 2 mol%, arachidic acid was 2 mol%, and erucic acid was 0.001 mol%. It was.

<Preparation of fatty acid silver dispersion B>
Recrystallized behenic acid 88 kg, distilled water 422 L, 5 mol / L NaOH aqueous solution 49.2 L and t-butyl alcohol 120 L were mixed and stirred at 75 ° C. for 1 hour to react to obtain sodium behenate solution B. Separately, 206.2 L (pH 4.0) of an aqueous solution containing 40.4 kg of silver nitrate was prepared and kept warm at 10 ° C. A reaction vessel containing 635 L of distilled water and 30 L of t-butyl alcohol was kept at 30 ° C., and with sufficient stirring, the total amount of the previous sodium behenate solution B and the total amount of silver nitrate aqueous solution were kept at a constant flow rate for 93 minutes 15 Added over seconds and 90 minutes. At this time, only the silver nitrate aqueous solution is added for 11 minutes after the start of the addition of the silver nitrate aqueous solution, and then the addition of the sodium behenate solution B is started. After the addition of the silver nitrate aqueous solution, only the sodium behenate solution B is added for 14 minutes and 15 seconds Was added. At this time, the temperature in the reaction vessel was 30 ° C., and the external temperature was controlled so that the liquid temperature was constant. The pipe of the addition system for the sodium behenate solution B was kept warm by circulating hot water outside the double pipe so that the liquid temperature at the outlet at the tip of the addition nozzle was 75 ° C. Moreover, the piping of the addition system of the silver nitrate aqueous solution was kept warm by circulating cold water outside the double pipe. The addition position of the sodium behenate solution B and the addition position of the silver nitrate aqueous solution were symmetrically arranged around the stirring axis, and were adjusted so as not to contact the reaction solution.

After completion of the addition of the sodium behenate solution B, the mixture was left stirring for 20 minutes at the same temperature, heated to 35 ° C. over 30 minutes, and then aged for 210 minutes. Immediately after completion of aging, the solid content was separated by centrifugal filtration, and the solid content was washed with water until the conductivity of filtered water reached 30 μS / cm. Thus, a fatty acid silver salt was obtained. The obtained solid content was stored as a wet cake without drying.
When the morphology of the obtained silver behenate particles was evaluated by electron microscope photography, the average values were a = 0.21 μm, b = 0.4 μm, c = 0.4 μm, average aspect ratio 2.1, and equivalent sphere diameter. The crystal had a coefficient of variation of 11%. (A, b, and c are the text provisions)

  19.3 kg of polyvinyl alcohol (trade name: PVA-217) and water are added to a wet cake corresponding to a dry solid content of 260 kg to make a total amount of 1000 kg, and then slurried with a dissolver blade, and a pipeline mixer (manufactured by Mizuho Kogyo) : PM-10 type).

Next, the pre-dispersed stock solution is adjusted to a pressure of 1150 kg / cm ² in a disperser (trade name: Microfluidizer M-610, manufactured by Microfluidics International Corporation, using a Z-type interaction chamber) three times. Treatment gave a silver behenate dispersion. The cooling operation was carried out by installing a serpentine heat exchanger before and after the interaction chamber, and adjusting the temperature of the refrigerant to a dispersion temperature of 18 ° C.

3) Preparation of reducing agent dispersion << Preparation of reducing agent-1 dispersion >>
10 kg of water is added to 16 kg of a 10 mass% aqueous solution of reducing agent-1 (2,2′-methylenebis- (4-ethyl-6-tert-butylphenol)) and 10% by weight of a modified polyvinyl alcohol (Kuraray Co., Ltd., Poval MP203). Add and mix well to make a slurry. This slurry was fed with a diaphragm pump, dispersed for 3 hours in a horizontal sand mill (UVM-2: manufactured by Imex Co., Ltd.) filled with zirconia beads having an average diameter of 0.5 mm, and then benzoisothiazolinone sodium salt 0. 2 g and water were added to prepare a reducing agent concentration of 25% by mass. This dispersion was heat-treated at 60 ° C. for 5 hours to obtain a reducing agent-1 dispersion. The reducing agent particles contained in the reducing agent dispersion thus obtained had a median diameter of 0.40 μm and a maximum particle diameter of 1.4 μm or less. The obtained reducing agent dispersion was filtered through a polypropylene filter having a pore size of 3.0 μm to remove foreign substances such as dust and stored.

<< Preparation of Reducing Agent-2 Dispersion >>
10 masses of reducing agent-2 (6,6′-di-t-butyl-4,4′-dimethyl-2,2′-butylidenediphenol) and modified polyvinyl alcohol (Kuraray Co., Ltd., Poval MP203) 10 kg of water was added to 16 kg of% aqueous solution and mixed well to obtain a slurry. This slurry was fed with a diaphragm pump and dispersed for 3 hours 30 minutes in a horizontal sand mill (UVM-2: manufactured by Imex Co., Ltd.) filled with zirconia beads having an average diameter of 0.5 mm, and then benzoisothiazolinone sodium salt 0.2 g and water were added to prepare a reducing agent concentration of 25% by mass. This dispersion was heated at 40 ° C. for 1 hour, and then further heated at 80 ° C. for 1 hour to obtain a reducing agent-2 dispersion. The reducing agent particles contained in the reducing agent dispersion thus obtained had a median diameter of 0.50 μm and a maximum particle diameter of 1.6 μm or less. The obtained reducing agent dispersion was filtered through a polypropylene filter having a pore size of 3.0 μm to remove foreign substances such as dust and stored.

4) Preparation of Hydrogen Bonding Compound-1 Dispersion 10 kg of hydrogen bonding compound-1 (tri (4-t-butylphenyl) phosphine oxide) and modified polyvinyl alcohol (Kuraray Co., Ltd., Poval MP203) 10 kg of water was added to 16 kg of the aqueous solution and mixed well to obtain a slurry. This slurry was fed with a diaphragm pump, and dispersed for 4 hours in a horizontal sand mill (UVM-2: manufactured by Imex Co., Ltd.) filled with zirconia beads having an average diameter of 0.5 mm. 2 g and water were added to prepare a hydrogen bonding compound concentration of 25% by mass. The dispersion was heated at 40 ° C. for 1 hour and then further heated at 80 ° C. for 1 hour to obtain a hydrogen bonding compound-1 dispersion. The hydrogen bonding compound particles contained in the hydrogen bonding compound dispersion thus obtained had a median diameter of 0.45 μm and a maximum particle diameter of 1.3 μm or less. The obtained hydrogen bonding compound dispersion was filtered through a polypropylene filter having a pore size of 3.0 μm to remove foreign substances such as dust and stored.

5) Preparation of Development Accelerator-1 Dispersion 10 kg of Development Accelerator-1 and 20 kg of 10% by weight aqueous solution of modified polyvinyl alcohol (Kuraray Co., Ltd., Poval MP203) were added with 10 kg of water and mixed well. To make a slurry. This slurry was fed with a diaphragm pump and dispersed for 3 hours 30 minutes in a horizontal sand mill (UVM-2: manufactured by Imex Co., Ltd.) filled with zirconia beads having an average diameter of 0.5 mm, and then benzoisothiazolinone sodium salt 0.2 g and water were added to adjust the concentration of the development accelerator to 20% by mass to obtain a development accelerator-1 dispersion. The development accelerator particles contained in the development accelerator dispersion thus obtained had a median diameter of 0.48 μm and a maximum particle diameter of 1.4 μm or less. The obtained development accelerator dispersion was filtered through a polypropylene filter having a pore size of 3.0 μm to remove foreign substances such as dust and stored.
6) Preparation of Dispersion of Development Accelerator-2 and Color Adjuster-1 The solid dispersion of Development Accelerator-2 and Color Adjuster-1 was also dispersed by the same method as Development Accelerator-1, each having 20 mass. % And 15% by mass dispersion liquid were obtained.

7) Preparation of polyhalogen compound << Preparation of organic polyhalogen compound-1 dispersion >>
10 kg of organic polyhalogen compound-1 (tribromomethanesulfonylbenzene), 10 kg of a 20% by weight aqueous solution of modified polyvinyl alcohol (Poval MP203 manufactured by Kuraray Co., Ltd.), 0.4 kg of a 20% by weight aqueous solution of sodium triisopropylnaphthalenesulfonate, Then, 14 kg of water was added and mixed well to obtain a slurry. This slurry was fed with a diaphragm pump and dispersed for 5 hours in a horizontal sand mill (UVM-2: manufactured by Imex Co., Ltd.) filled with zirconia beads having an average diameter of 0.5 mm. 2 g and water were added to prepare an organic polyhalogen compound concentration of 26% by mass to obtain an organic polyhalogen compound-1 dispersion. The organic polyhalogen compound particles contained in the polyhalogen compound dispersion thus obtained had a median diameter of 0.41 μm and a maximum particle diameter of 2.0 μm or less. The obtained organic polyhalogen compound dispersion was filtered through a polypropylene filter having a pore size of 10.0 μm to remove foreign substances such as dust and stored.

<< Preparation of organic polyhalogen compound-2 dispersion >>
10 kg of an organic polyhalogen compound-2 (N-butyl-3-tribromomethanesulfonylbenzoamide), 20 kg of a 10% by weight aqueous solution of modified polyvinyl alcohol (Poval MP203 manufactured by Kuraray Co., Ltd.), and 20 of sodium triisopropylnaphthalenesulfonate 0.4 kg of a mass% aqueous solution was added and mixed well to obtain a slurry. This slurry was fed with a diaphragm pump and dispersed for 5 hours in a horizontal sand mill (UVM-2: manufactured by Imex Co., Ltd.) filled with zirconia beads having an average diameter of 0.5 mm. 2 g and water were added to prepare an organic polyhalogen compound concentration of 30% by mass. This dispersion was heated at 40 ° C. for 5 hours to obtain an organic polyhalogen compound-2 dispersion. The organic polyhalogen compound particles contained in the polyhalogen compound dispersion thus obtained had a median diameter of 0.40 μm and a maximum particle diameter of 1.3 μm or less. The obtained organic polyhalogen compound dispersion was filtered through a polypropylene filter having a pore size of 3.0 μm to remove foreign substances such as dust and stored.

8) Preparation of phthalazine compound-1 solution >>
8 kg of Kuraray Co., Ltd. modified polyvinyl alcohol MP203 was dissolved in 174.57 kg of water, and then 3.15 kg of a 20 mass% aqueous solution of sodium triisopropylnaphthalenesulfonate and 70 mass of phthalazine compound-1 (6-isopropylphthalazine). 14.28 kg of a% aqueous solution was added to prepare a 5 mass% solution of phthalazine compound-1.

9) Preparation of mercapto compound << Preparation of aqueous solution of mercapto compound-1 >>
7 g of mercapto compound-1 (1- (3-sulfophenyl) -5-mercaptotetrazole sodium salt) was dissolved in 993 g of water to obtain a 0.7% by mass aqueous solution.

<< Preparation of Mercapto Compound-2 Aqueous Solution >>
20 g of mercapto compound-2 (1- (3-methylureidophenyl) -5-mercaptotetrazole) was dissolved in 980 g of water to obtain a 2.0 mass% aqueous solution.

10) Preparation of Pigment-1 Dispersion C.I. I. Pigment Blue 60 (64 g) and Kao Corp. Demol N (6.4 g) were added to 250 g of water and mixed well to obtain a slurry. Prepare 800 g of zirconia beads having an average diameter of 0.5 mm, put them in a vessel together with the slurry, and disperse with a disperser (1/4 G sand grinder mill: manufactured by IMEX Co., Ltd.) for 25 hours. A pigment-1 dispersion was obtained by adjusting the concentration to 5% by mass. The pigment particles contained in the pigment dispersion thus obtained had an average particle size of 0.21 μm.

11) Preparation of SBR latex solution SBR latex was prepared as follows.
In a polymerization kettle of a gas monomer reactor (TAS-2J type manufactured by Pressure Glass Industrial Co., Ltd.), 287 g of distilled water and a surfactant (Pionin A-43-S (manufactured by Takemoto Yushi Co., Ltd.)): solid content 48.5 (Mass%) 7.73 g, 1 mol / liter NaOH 14.06 ml, ethylenediaminetetraacetic acid tetrasodium salt 0.15 g, styrene 255 g, acrylic acid 11.25 g, tert-dodecyl mercaptan 3.0 g were put, the reaction vessel was sealed and the stirring speed was Stir at 200 rpm. After degassing with a vacuum pump and repeating nitrogen gas replacement several times, 108.75 g of 1,3-butadiene was injected and the internal temperature was raised to 60 ° C. A solution obtained by dissolving 1.875 g of ammonium persulfate in 50 ml of water was added thereto, and the mixture was stirred as it was for 5 hours. The temperature was further raised to 90 ° C. and stirred for 3 hours. After the reaction was completed, the internal temperature was lowered to room temperature, and then Na ⁺ ion: NH ₄ ⁺ ion = 1: 1 using 1 mol / liter NaOH and NH ₄ OH. Addition treatment was performed so that the molar ratio was 5.3 (molar ratio), and the pH was adjusted to 8.4. Thereafter, the mixture was filtered through a polypropylene filter having a pore size of 1.0 μm to remove foreign substances such as dust and stored to obtain 774.7 g of SBR latex. When the halogen ions were measured by ion chromatography, the chloride ion concentration was 3 ppm. As a result of measuring the concentration of the chelating agent by high performance liquid chromatography, it was 145 ppm.

  The latex has an average particle size of 90 nm, Tg = 17 ° C., solid content concentration of 44 mass%, equilibrium moisture content at 25 ° C. and 60% RH, 0.6 mass%, ion conductivity of 4.80 mS / cm (measurement of ion conductivity is A latex stock solution (44 mass%) was measured at 25 ° C. using a conductivity meter CM-30S manufactured by Toa Denpa Kogyo Co., Ltd.).

  SBR latexes having different Tg can be prepared in the same manner by appropriately changing the ratio of styrene and butadiene.

2. Preparation of coating liquid 1) Preparation of image forming layer coating liquid-1A 1000 g of fatty acid silver dispersion A obtained above, 135 ml of water, 35 g of pigment-1 dispersion, 19 g of organic polyhalogen compound-1 dispersion, organic polyhalogen compound- 2 dispersion 58 g, phthalazine compound-1 solution 162 g, SBR latex (Tg: 17 ° C.) liquid 1060 g, reducing agent-1 dispersion 75 g, reducing agent-2 dispersion 75 g, hydrogen bonding compound-1 dispersion 106 g, development 4.8 g of accelerator-2 dispersion, 9 ml of mercapto compound-1 aqueous solution, and 27 ml of mercapto compound-2 aqueous solution were sequentially added, and 118 g of silver halide mixed emulsion A was added immediately before coating, followed by mixing well. The solution was fed directly to the coating die and applied.

The viscosity of the image forming layer coating solution was 25 [mPa · s] at 40 ° C. (No. 1 rotor, 60 rpm) as measured with a B-type viscometer of Tokyo Keiki.
The viscosity of the coating solution at 38 ° C. using a Haake RheoStress RS150 is 32, 35, 33, 26, 17 [mPa · s].
The amount of zirconium in the coating solution was 0.32 mg per 1 g of silver.

2) Preparation of image forming layer coating liquid-1B 752 g of fatty acid silver dispersion A obtained above, 200 ml of water, 35 g of pigment-1 dispersion, 19 g of organic polyhalogen compound-1 dispersion, 58 g of organic polyhalogen compound-2 dispersion , 162 g of phthalazine compound-1 solution, 424 g of SBR latex (Tg: 17 ° C.) liquid, 56 g of reducing agent-1 dispersion, 56 g of reducing agent-2 dispersion, 106 g of hydrogen bonding compound-1 dispersion, development accelerator-2 3.6 g of the dispersion, 9 ml of mercapto compound-1 aqueous solution, and 27 ml of mercapto compound-2 aqueous solution were sequentially added, and 118 g of silver halide mixed emulsion A was added immediately before coating, and the well mixed image forming layer coating solution was directly applied to the coating die. The solution was fed and applied.

The viscosity of the image forming layer coating solution was 26 [mPa · s] at 40 ° C. (No. 1 rotor, 60 rpm) as measured with a B-type viscometer of Tokyo Keiki.
The viscosity of the coating solution at 38 ° C. using a Haake RheoStress RS150 is 38, 39, 35, 28, 19 [mPa · s].
The amount of zirconium in the coating solution was 0.32 mg per 1 g of silver.

3) Preparation of image forming layer coating liquid-2A 1000 g of fatty acid silver dispersion B obtained above, 135 ml of water, 36 g of pigment-1 dispersion, 25 g of organic polyhalogen compound-1 dispersion, 39 g of organic polyhalogen compound-2 dispersion , 171 g of phthalazine compound-1 solution, 1060 g of SBR latex (Tg: 17 ° C.) liquid, 153 g of reducing agent-2 dispersion, 55 g of hydrogen bonding compound-1 dispersion, 4.8 g of development accelerator-1 dispersion, development acceleration Agent-2 dispersion 5.2 g, color tone modifier-1 dispersion 2.1 g, mercapto compound-2 aqueous solution 8 ml were sequentially added, and silver halide mixed emulsion A140 g was added immediately before coating, and mixed well. The coating solution was fed directly to the coating die and applied.
The viscosity of the image forming layer coating solution was 40 [mPa · s] at 40 ° C. (No. 1 rotor, 60 rpm) as measured with a B-type viscometer of Tokyo Keiki.
The viscosity of the coating solution at 38 ° C. using a Haake RheoStress RS150 is 30, 43, 41, 28, 20 [mPa · s] at shear rates of 0.1, 1, 10, 100, 1000 [1 / second], respectively. s].
The amount of zirconium in the coating solution was 0.30 mg per 1 g of silver.

4) Preparation of image forming layer coating liquid-2B 752 g of fatty acid silver dispersion B obtained above, 200 ml of water, 36 g of pigment-1 dispersion, 25 g of organic polyhalogen compound-1 dispersion, 39 g of organic polyhalogen compound-2 dispersion , 171 g of phthalazine compound-1 solution, 424 g of SBR latex (Tg: 17 ° C.) liquid, 113 g of reducing agent-2 dispersion, 55 g of hydrogen bonding compound-1 dispersion, 4.8 g of development accelerator-1 dispersion, development acceleration 3.9 g of agent-2 dispersion, 2.1 g of color adjusting agent-1 dispersion, and 8 ml of mercapto compound-2 aqueous solution were added successively, and 140 g of silver halide mixed emulsion A was added immediately before coating and mixed well. The coating solution was fed directly to the coating die and applied.
The viscosity of the image forming layer coating solution was 42 [mPa · s] at 40 ° C. (No. 1 rotor, 60 rpm) as measured with a B-type viscometer of Tokyo Keiki.
The viscosity of the coating solution at 38 ° C. using a Haake RheoStress RS150 is 33, 47, 44, 31, 22 [mPa · s] at shear rates of 0.1, 1, 10, 100, and 1000 [1 / second], respectively. s].
The amount of zirconium in the coating solution was 0.30 mg per 1 g of silver.

5) Preparation of intermediate layer coating solution A 1000 g of polyvinyl alcohol PVA-205 (manufactured by Kuraray Co., Ltd.), 163 g of pigment-1 dispersion, blue dye compound-1 (manufactured by Nippon Kayaku Co., Ltd .: Kayafect Turquoise RN Liquid) 150) 33 g of 18.5 wt% aqueous solution, 27 ml of 5 wt% aqueous solution of di (2-ethylhexyl) sodium sulfosuccinate, methyl methacrylate / styrene / butyl acrylate / hydroxyethyl methacrylate / acrylic acid copolymer (copolymer weight ratio 57 / 8/28/5/2) 27% 5% aqueous solution of aerosol OT (manufactured by American Cyanamid Co., Ltd.) in 4200 ml of 19% by weight latex, 135 ml of 20% by weight aqueous solution of diammonium phthalate, total amount 10000g Add water so that the pH is 7.5. The intermediate layer coating solution was adjusted with aOH and fed to the coating die so as to be 8.9 ml / m ² .
The viscosity of the coating solution was 58 [mPa · s] at a B-type viscometer of 40 ° C. (No. 1 rotor, 60 rpm).

6) Preparation of surface protective layer first layer coating solution 100 g of inert gelatin and 10 mg of benzoisothiazolinone were dissolved in 840 ml of water, and a methyl methacrylate / styrene / butyl acrylate / hydroxyethyl methacrylate / acrylic acid copolymer (copolymerization weight ratio). 57/8/28/5/2) Latex 19% by weight liquid 180g, phthalic acid 15% by weight methanol solution 46ml, sulfosuccinic acid di (2-ethylhexyl) sodium salt 5% by weight aqueous solution 5.4ml was added. The mixture was mixed and 40 ml of 4% by weight chromium alum mixed with a static mixer immediately before coating was fed to the coating die so that the amount of the coating solution was 26.1 ml / m ² .
The viscosity of the coating solution was 20 [mPa · s] at a B-type viscometer of 40 ° C. (No. 1 rotor, 60 rpm).

7) Preparation of surface protective layer second layer coating solution <Preparation of surface protective layer second layer coating solution-1>
100 g of inert gelatin and 10 mg of benzoisothiazolinone are dissolved in 800 ml of water, 40 g of a 10% by weight emulsion of liquid paraffin, 40 g of a 10% by weight emulsion of dipentaerythrityl hexaisostearate, methyl methacrylate / styrene / butyl acrylate / hydroxyethyl Methacrylate / acrylic acid copolymer (copolymerization weight ratio 57/8/28/5/2) Latex 19% by weight liquid 180g, phthalic acid 15% by weight methanol solution 40ml, fluorosurfactant (F-1) 1 5.5 ml of mass% solution, 5.5 ml of 1 mass% aqueous solution of fluorosurfactant (F-2), 28 ml of 5 mass% aqueous solution of di (2-ethylhexyl) sodium sulfosuccinate, polymethyl methacrylate fine particles (Average particle size 4.2 μm) 15 g was mixed. The was a surface protective layer coating solution was fed to a coating die so that 8.3 ml / m ^2.
The viscosity of the coating solution was 19 [mPa · s] at a B-type viscometer of 40 ° C. (No. 1 rotor, 60 rpm).

<Preparation of surface protective layer second layer coating solution -2 to 6>
The polymethyl methacrylate fine particles used in the preparation of the surface protective layer second layer coating solution-1 were 6.3 μm (15 g), 8 μm (15 g), 10 μm (18 g), 2.7 μm (15 g), and 13 μm (15 g), respectively. The surface protective layer second layer coating liquids 2 to 6 were prepared in the same manner except that the polymethyl methacrylate fine particles having a particle size of 5 were used.

3. Preparation of photothermographic material 1) Preparation of photothermographic material-101 Image forming layer coating solution-1A, intermediate layer coating solution A, surface protective layer first layer coating solution, surface from the undercoat surface on the surface opposite to the back surface Samples of photothermographic materials were prepared by simultaneous multi-layer coating by the slide bead coating method in the order of protective layer second layer coating solution-1. At this time, the image forming layer and the intermediate layer coating solution were adjusted to 31 ° C., the surface protective layer first layer coating solution was adjusted to 36 ° C., and the surface protective layer second layer coating solution was adjusted to 37 ° C.
The film thickness of the image forming layer is 20 μm, and the coating amount (g / m ² ) of each compound in the image forming layer is as follows.

Fatty acid silver 5.42
Pigment (C.I. Pigment Blue 60) 0.036
Polyhalogen compound-1 0.12
Polyhalogen compound-2 0.25
Phthalazine Compound-1 0.18
SBR latex 9.70
Reducing agent-1 0.40
Reducing agent-2 0.40
Hydrogen bonding compound-1 0.58
Development accelerator-2 0.02
Mercapto Compound-1 0.002
Mercapto compound-2 0.012
Silver halide (as Ag) 0.10

The coating and drying conditions are as follows.
The coating was performed at a speed of 160 m / min, the gap between the coating die tip and the support was set to 0.10 to 0.30 mm, and the pressure in the decompression chamber was set to be 196 to 882 Pa lower than the atmospheric pressure. The support was neutralized with an ion wind before coating.
In the subsequent chilling zone, after cooling the coating solution with a wind at a dry bulb temperature of 10 to 20 ° C., it is transported in a non-contact type, and is dried at a dry bulb temperature of 23 to 45 ° C. It dried with the dry wind of the wet bulb temperature 15-21 degreeC.
After drying, the humidity was adjusted at 25 ° C. and humidity of 40 to 60% RH, and then the film surface was heated to 70 to 90 ° C. After heating, the film surface was cooled to 25 ° C.
The photothermographic material thus produced had a matte degree of Beck smoothness as shown in Table 1 on the image forming layer surface side and a back surface of 130 seconds. Further, the pH of the film surface on the image forming layer surface side was measured and found to be 6.0.

2) Preparation of photothermographic material-102 to 104 In the preparation of photothermographic material-101, the surface protective layer second layer coating solution-2 to 4 were used in the same manner as the surface protective layer second layer coating solution-1. Photothermographic materials -102 to 104 were prepared in the same manner except that any of the above was changed.

3) Preparation of photothermographic material-105 to 110 In the preparation of photothermographic material-101, the surface protective layer second layer coating solution-1 to 6 were used as the surface protective layer second layer coating solution-1. The image forming layer coating solution was changed from 1A to 1B, and the film thickness of the image forming layer was adjusted to 20 μm, except that the film thickness was adjusted to 10 μm. Materials -105 to 110 were made.
The film thickness of the image forming layer is 10 μm, and the coating amount (g / m ² ) of each compound in the image forming layer is as follows.

Fatty acid silver 4.08
Pigment (C.I. Pigment Blue 60) 0.036
Polyhalogen compound-1 0.12
Polyhalogen compound-2 0.25
Phthalazine Compound-1 0.18
SBR latex 3.88
Reducing agent-1 0.30
Reducing agent-2 0.30
Hydrogen bonding compound-1 0.58
Development accelerator-2 0.015
Mercapto Compound-1 0.002
Mercapto compound-2 0.012
Silver halide (as Ag) 0.10

The coating and drying conditions are as follows.
The coating was performed at a speed of 160 m / min, the gap between the coating die tip and the support was set to 0.10 to 0.30 mm, and the pressure in the decompression chamber was set to be 196 to 882 Pa lower than the atmospheric pressure. The support was neutralized with an ion wind before coating.
In the subsequent chilling zone, after cooling the coating solution with a wind at a dry bulb temperature of 10 to 20 ° C., it is transported in a non-contact type, and is dried at a dry bulb temperature of 23 to 45 ° C. It dried with the dry wind of the wet bulb temperature 15-21 degreeC.
After drying, the humidity was adjusted at 25 ° C. and humidity of 40 to 60% RH, and then the film surface was heated to 70 to 90 ° C. After heating, the film surface was cooled to 25 ° C.
The photothermographic material thus produced had a matte degree of Beck smoothness, the value on the image forming layer side as shown in Table 1, and the back side of 130 seconds. The pH of the film surface on the image forming layer side was measured and found to be 5.7.

4) Preparation of photothermographic material-201 The photothermographic material-101 was prepared in the same manner as the photothermographic material-101 except that the image forming layer coating solution-1 was changed to the image forming layer coating solution-2A. Photothermographic material-201 was produced.
The coating amount (g / m ² ) of each compound in the image forming layer at this time is as follows.

Fatty acid silver 5.27
Pigment (C.I. Pigment Blue 60) 0.036
Polyhalogen compound-1 0.14
Polyhalogen compound-2 0.28
Phthalazine Compound-1 0.18
SBR latex 9.43
Reducing agent-2 0.77
Hydrogen bonding compound-1 0.28
Development accelerator-1 0.019
Development accelerator-2 0.016
Color tone adjusting agent-1 0.006
Mercapto compound-2 0.003
Silver halide (as Ag) 0.13

5) Preparation of photothermographic material-202 to 204 In the preparation of photothermographic material-201, the surface protective layer second layer coating solution-2 to 6 was used where surface protective layer second layer coating solution-1 was used. Photothermographic materials -202 to 204 were prepared in the same manner except that any of the above was changed.

6) Photothermographic material—Preparation of 205-210 Photothermographic material—Preparation of 205-220 Photothermographic material—201 In the preparation of photothermographic material-201, surface protection layer second layer coating solution-1 was used for surface protection. Change to any one of the second layer coating solution-1 to 6, change the image forming layer coating solution from 2A to 2B, and adjust the film thickness of the image forming layer to 20 μm to 10 μm. Except for the above, photothermographic materials -205 to 210 were prepared in the same manner.
The film thickness of the image forming layer is 10 μm, and the coating amount (g / m ² ) of each compound in the image forming layer is as follows.
The coating amount (g / m ² ) of each compound in the image forming layer at this time is as follows.

Fatty acid silver 3.96
Pigment (C.I. Pigment Blue 60) 0.036
Polyhalogen compound-1 0.14
Polyhalogen compound-2 0.28
Phthalazine Compound-1 0.18
SBR latex 3.77
Reducing agent-2 0.57
Hydrogen bonding compound-1 0.28
Development accelerator-1 0.019
Development accelerator-2 0.012
Color tone adjusting agent-1 0.006
Mercapto compound-2 0.003
Silver halide (as Ag) 0.13

  The chemical structures of the compounds used in the examples of the present invention are shown below.

4). Evaluation of photographic performance 1) Preparation The obtained sample was cut into half-cut size (43 cm length x 35 cm width), packaged in the following packaging materials in an environment of 25 ° C and 50%, and stored at room temperature for 2 weeks. The following evaluation was performed.
2) Packaging material PET 10 μm / PE 12 μm / aluminum foil 9 μm / Ny 15 μm / polyethylene 50 μm containing 3% by mass of carbon
Oxygen permeability: 0.02 ml / atm · m ² · 25 ° C · day, moisture permeability: 0.10 g / atm · m ² · 25 ° C · day

3) Exposure / development of photosensitive material The photothermographic materials -101 to 110 were prepared at a density of 1. with a dry laser imager FM-DP L (mounted on a 660 nm semiconductor laser with a maximum output of 60 mW (IIIB)), Fuji Medical Co., Ltd. The film was exposed and heat-developed so as to be a half solid of 2 (total of 24 seconds with four panel heaters set at 112 ° C.-119 ° C.-121 ° C.-121 ° C.). The conveyance speed at the time of heat development was 17 mm / second.
The photothermographic material 201-210 is exposed and heat-developed so that it becomes half solid with a density of 1.2 using Fuji Medical's dry laser imager DRYPIX7000 (with a 660 nm semiconductor laser with a maximum output of 50 mW (IIIB)). (Total of 14 seconds with three panel heaters set at 107 ° C-121 ° C-121 ° C). The conveyance speed at the time of heat development was 28.933 mm / sec.
All exposure / developing machines are equipped with a plate-type heater, and are transported while sliding the photosensitive material during thermal development.

4) Evaluation of photographic performance <Scratch resistance>
Five half-cut size photosensitive materials that were exposed and developed by the above-described method and output at a density of 1.2 were prepared and subjected to the following sensory evaluation. The sensory evaluation was performed by five or more people, and the result of the person with the most severe evaluation was taken as the evaluation result. The reflection observation was performed in a room with a fluorescent lamp response on the ceiling in an environment of 1000 lux, and the transmission observation was performed using a 10000 lux Schaukasten. The criteria for sensory evaluation were as follows.
A: The image forming layer is not scratched even when observed by reflection or transmission.
◯: When the image is observed by reflection, a kiss is confirmed in the image forming layer, but the scratch is not visible when transmitted.
Δ: Scratches are observed in the image forming layer in both reflection and transmission, but there is at least one photosensitive material at a level that does not cause any problem in interpretation.
X: Scratches are observed in the image forming layer in both reflection and transmission, and there is a problem in interpretation.

<Adhesion resistance>
The half-cut size photosensitive material developed without exposure is cut into a size of 3.5 cm × 3.5 cm, and after conditioning for 16 hours in an environment of 25 ° C. and 75% RH, the image forming layer surface and the back surface face each other. The photosensitive material was stacked and enclosed in a moisture-proof bag. After that, a load of 450 g was applied and left in an environment of 40 ° C. for 10 days. After being left for 2 hours in an environment at 25 ° C., the moisture-proof bag was opened, and the sample in which the image forming layer surface and the back surface overlapped was slowly peeled off. The sensory evaluation was performed according to the following criteria depending on how the emulsion surface of the peeled sample was damaged.
A: No adhesion at all.
○: The film does not peel but remains after bonding.
Δ: Less than 1% of the total photosensitive material area, but peeling of the film due to adhesion is observed.

<Granular quality>
The half-cut size light-sensitive material which was exposed and developed by the above-described method and output at a density of 1.2 was prepared, and the following sensory evaluation was performed. The sensory evaluation was performed by five or more people, and the result of the person with the most severe evaluation was taken as the evaluation result.
A: Grain is good and no rough feeling is felt.
○: Graininess is felt and there is a slight roughness, but there is no problem in interpretation.
Δ: Graininess is felt bad, but in the X-ray photograph of the chest, graininess is not felt at all and there is no problem.
X: Graininess is felt bad, and the chest X-ray photograph shows that the graininess is bad, and there is a problem.

<Evaluation of matting agent peeling>
The surface of the half-cut photographic material exposed and developed by the above method was observed with an optical microscope to see if the matting agent was peeled off in the range of 1 cm × 1 cm. Observation was averaged for 5 samples and evaluated according to the following criteria. In addition, the observation position of the half-cut sensitizing material was observed in a 1 cm square range centering on a portion 1 cm inside from the film notch portion.
A: There is no peeling off of the matting agent.
○: Matting agent peeling off is less than 0.5 pieces / sheet.
(Triangle | delta): Matting agent peeling is less than 1.1 piece, 0.5 piece or more / 1 sheet.

The evaluation results are shown in Table 1.

  As shown in Table 1, when a matting agent having an image forming layer thickness of 12 μm or less and a matting agent having a diameter of 30% or more of the thickness is used, the image quality is good and the matting agent is peeled off. Without improving the scratch resistance and adhesion resistance.

1. Preparation of coating liquid 1) Preparation of intermediate layer coating liquid B Polyvinyl alcohol PVA-205 (manufactured by Kuraray Co., Ltd.) 1000 g, pigment-1 dispersion 163 g, blue dye compound-1 (manufactured by Nippon Kayaku Co., Ltd.): Kayafect Turquoise RN Liquid 150) 18.5% by weight aqueous solution 33g, sulfosuccinic acid di (2-ethylhexyl) sodium salt 5% by weight aqueous solution 27ml, methyl methacrylate / styrene / butyl acrylate / hydroxyethyl methacrylate / acrylic acid copolymer (co-polymer) Polymerization weight ratio 57/8/28/5/2) 27% 5% by weight aqueous solution of aerosol OT (manufactured by American Cyanamid) and 20% by weight aqueous solution of diammonium phthalate in 4200 ml of 19% latex by weight 135 ml, polymethyl methacrylate fine particles (average particle size 8 μm) 10 Sequentially add 0 g, add water to a total amount of 10000 g, adjust with NaOH to a pH of 7.5 to make an intermediate layer coating solution, and send to the coating die to 8.9 ml / m ^2. did.
The viscosity of the coating solution was 58 [mPa · s] at a B-type viscometer of 40 ° C. (No. 1 rotor, 60 rpm).

2) Preparation of surface protective layer second layer coating solution-7 In the preparation of surface protective layer second layer coating solution-1 of Example 1, the same procedure was carried out except that it was prepared without adding polymethyl methacrylate fine particles. A protective layer second layer coating solution-7 was prepared.

2. Preparation of photothermographic material-3, 4 In preparation of photothermographic material-108 of Example 1, the intermediate layer coating solution A was changed to the intermediate layer coating solution B, and the surface protective layer second layer coating solution was used. Photothermographic material-3 was produced in the same manner except that the surface protective layer second layer coating solution-7 was used.
Further, in the production of the photothermographic material-208 of Example 1, the intermediate layer coating solution A was changed to the intermediate layer coating solution B, and the surface protective layer second layer coating solution was changed to the surface protective layer second layer coating solution- Photothermographic material-4 was prepared in the same manner except that the number was changed to 7.

3. Exposure / Development The photothermographic material-3 was exposed and heat-developed in the same manner as the photothermographic materials-101 to 110 in Example 1.
The photothermographic material-4 was exposed and heat-developed in the same manner as the photothermographic material-201 to 210 of Example 1.

4. Evaluation In the same manner as in Example 1, the photothermographic materials-3 and 4 were evaluated. The results are shown in Table 2.

  Even if the addition layer of the matting agent is changed from the second surface protective layer to the intermediate layer, if the matting agent is 30% or more of the film thickness of the image forming layer, the granularity of the image quality is good and the matting agent is peeled off. Thus, the photothermographic material has improved scratch resistance and adhesion resistance.

(Preparation of PET support)
In the preparation of the PET support of Example 1, undercoating, the base coating solution formulation (1) was applied to one side of the support, and the base coating solution formulations (2) and (3) were applied to the other side. Undercoat coating liquid formulation (1) was applied on both sides so that the wet coating amount was 6.6 ml / m 2 (per one side), and dried at 180 ° C. for 5 minutes to prepare an undercoat support.

(Back layer)
In Example 1, the back layer was provided, but in Example 3, the back layer was not provided.

(Image forming layer, intermediate layer, and surface protective layer)
1. Preparation of coating materials 1) Silver halide emulsion << Preparation of silver halide emulsion A >>
4.3 ml of 1% by weight potassium iodide solution is added to 1421 ml of distilled water, and 3.5 ml of 0.5 mol / L sulfuric acid, 36.5 g of phthalated gelatin, and 5 mass of 2,2 ′-(ethylenedithio) diethanol. The solution to which 160 ml of methanol solution was added was stirred in a stainless steel reaction vessel while maintaining the liquid temperature at 75 ° C., and 22.22 g of silver nitrate was added to distilled water and diluted to 218 ml. Solution B in which 6 g was diluted to 366 ml with distilled water was added in a total amount over 16 minutes at a constant flow rate, and solution B was added by the control double jet method while maintaining pAg at 10.2. Thereafter, 10 ml of a 3.5% by mass aqueous hydrogen peroxide solution was added, and 10.8 ml of a 10% by mass aqueous solution of benzimidazole was further added. Further, a solution C in which distilled water was added to 51.86 g of silver nitrate and diluted to 508.2 ml, and a solution D in which 63.9 g of potassium iodide were diluted to 639 ml with distilled water, and solution C was added at a constant flow rate over 80 minutes. The entire amount was added, and Solution D was added by the control double jet method while maintaining pAg at 10.2. The total amount of potassium hexachloroiridium (III) was added 10 minutes after the start of the addition of the solution C and the solution D so as to be 1 × 10 ⁻⁴ mol per mol of silver. Further, 5 seconds after the completion of the addition of the solution C, an aqueous solution of potassium iron (II) hexacyanide was added in an amount of 3 × 10 ⁻⁴ mol per mol of silver. The pH was adjusted to 3.8 using 0.5 mol / L sulfuric acid, stirring was stopped, and a precipitation / desalting / water washing step was performed. The pH was adjusted to 5.9 with 1 mol / L sodium hydroxide to prepare a silver halide dispersion having a pAg of 11.0.

  The silver halide emulsion A is a pure silver iodide emulsion and has a plate shape having an average projected area diameter of 0.93 μm, an average projected area diameter variation coefficient of 17.7%, an average thickness of 0.057 μm, and an average aspect ratio of 16.3. The grains accounted for over 80% of the total projected area. The equivalent sphere diameter was 0.42 μm. As a result of analysis by X-ray powder diffraction analysis, 90% or more of silver iodide was present in the γ phase.

<< Preparation of silver halide emulsion B >>
One mole of tabular grain AgI emulsion prepared with silver halide emulsion A was placed in a reaction vessel. The pAg was 10.2 measured at 38 ° C. Then, by double jet addition, a 0.5 mol / liter KBr solution and a 0.5 mol / liter AgNO ₃ solution were added at 10 ml / min over 20 minutes to substantially add 10 mol% silver bromide to the AgI host. Epitaxially precipitated on the emulsion. During operation, pAg was maintained at 10.2. Furthermore, the pH was adjusted to 3.8 using 0.5 mol / L sulfuric acid, stirring was stopped, and a precipitation / desalting / water washing step was performed. The pH was adjusted to 5.9 with 1 mol / L sodium hydroxide to prepare a silver halide dispersion having a pAg of 11.0.

The silver halide dispersion was maintained at 38 ° C. with stirring, 5 ml of a 0.34 mass% 1,2-benzisothiazolin-3-one methanol solution was added, and the temperature was raised to 47 ° C. after 40 minutes. 20 minutes after the temperature increase, sodium benzenethiosulfonate was added in a methanol solution to 7.6 × 10 ⁻⁵ mol per 1 mol of silver, and 5 minutes later, tellurium sensitizer C was added in a methanol solution to a ratio of 2. 9 × 10 ⁻⁵ mol was added and aged for 91 minutes. Thereafter, 1.3 ml of a 0.8 mass% methanol solution of N, N′-dihydroxy-N ″ -diethylmelamine was added, and after 4 minutes, 5-methyl-2-mercaptobenzimidazole was added with 1 mol of silver with a methanol solution. ^Per mole of 4.8 × 10 ⁻³ mole, 1-phenyl-2-heptyl-5-mercapto-1,3,4-triazole in methanol solution to 5.4 × 10 ⁻³ mole and 1- A silver halide emulsion B was prepared by adding (3-methylureidophenyl) -5-mercaptotetrazole in an aqueous solution to 8.5 × 10 ⁻³ mol per mol of silver.

<< Preparation of silver halide emulsion C >>
In the same manner as silver halide emulsion A, the addition amount of a 5% by weight methanol solution of 2,2 ′-(ethylenedithio) diethanol, the temperature at the time of grain formation, and the addition time of solution A were appropriately changed. Emulsion C was prepared. Silver halide Emulsion C is a pure silver iodide emulsion, tabular grains having an average projected area diameter of 1.369 μm, an average projected area diameter variation coefficient of 19.7%, an average thickness of 0.130 μm, and an average aspect ratio of 11.1. Accounted for more than 80% of the total projected area. The equivalent sphere diameter was 0.71 μm. As a result of analysis by X-ray powder diffraction analysis, 90% or more of silver iodide was present in the γ phase.

<< Preparation of silver halide emulsion D >>
A silver halide emulsion D containing 10 mol% of silver bromide epitaxial was prepared in exactly the same manner as silver halide emulsion B, except that silver halide emulsion C was used.

≪Preparation of mixed emulsion for coating liquid≫
Dissolve silver halide emulsion B and silver halide emulsion D in a silver molar ratio of 5: 1, and add 7 × 10 ⁻³ mol of benzothiazolium iodide per mol of silver in a 1% by mass aqueous solution. did.
Further, the amount of the compound compounds 1, 2 and 3 that can be emitted by one-electron oxidation formed by one-electron oxidation to one electron or more is 2 × 10 ⁻³ mol per mol of silver halide. Was added.
Further, compounds 1 and 2 having an adsorbing group and a reducing group were added in an amount of 8 × 10 ⁻³ mol per mol of silver halide.
Further, water was added so that the silver halide content per liter of the mixed emulsion for coating solution was 15.6 g as silver.

<< Preparation of other additives >>
Other additives in the image forming layer, the intermediate layer, and the surface protective layer were prepared in the same manner as in Example 1.

2. Preparation of coating solution 1) Preparation of image forming layer coating solution-5 To 1000 g of the fatty acid silver dispersion obtained above and 276 ml of water, an organic polyhalogen compound-1 dispersion, an organic polyhalogen compound-2 dispersion, SBR latex (Tg: 17 ° C.) liquid, reducing agent-1 dispersion, reducing agent-2 dispersion, hydrogen bonding compound-1 dispersion, development accelerator-1 dispersion, development accelerator-2 dispersion, color tone The modifier-1 dispersion, the mercapto compound-1 aqueous solution, and the mercapto compound-2 aqueous solution were added sequentially, and after the addition of the silver iodide complex forming agent, the silver halide mixed emulsion for coating solution of silver halide was added in silver amount immediately before coating. 0.22 mol was added per 1 mol of fatty acid silver, mixed well, sent as it was to the coating die, and applied.

The viscosity of the image forming layer coating solution was 25 [mPa · s] at 40 ° C. (No. 1 rotor, 60 rpm) as measured with a B-type viscometer of Tokyo Keiki.
The viscosity of the coating solution at 25 ° C. using an RFS fluid spectrometer manufactured by Rheometrics Far East Co., Ltd. is 242, 65, 48 at shear rates of 0.1, 1, 10, 100, and 1000 [1 / second], respectively. 26 and 20 [mPa · s].
The amount of zirconium in the coating solution was 0.52 mg per 1 g of silver.

2) Preparation of intermediate layer coating solution-C 1000 g of polyvinyl alcohol PVA-205 (manufactured by Kuraray Co., Ltd.), methyl methacrylate / styrene / butyl acrylate / hydroxyethyl methacrylate / acrylic acid copolymer (copolymerization weight ratio 64/9 / 20/5/2) 27% 5% aqueous solution of aerosol OT (manufactured by American Cyanamid Co., Ltd.) in 4200 ml of 19% by weight latex solution, 135 ml of 20% by weight aqueous solution of diammonium phthalate, total amount 10000g Water was added to the solution and adjusted with NaOH so that the pH was 7.5 to obtain an intermediate layer coating solution, which was then fed to the coating die so as to be 9.1 ml / m ² .
The viscosity of the coating solution was 58 [mPa · s] at a B-type viscometer of 40 ° C. (No. 1 rotor, 60 rpm).

3) Preparation of surface protective layer first layer coating solution-2 64 g of inert gelatin was dissolved in water and a methyl methacrylate / styrene / butyl acrylate / hydroxyethyl methacrylate / acrylic acid copolymer (copolymerization weight ratio 64/9/20). / 5/2) 112 g of latex 19.0 wt% solution, 30 ml of 15 wt% methanol solution of phthalic acid, 23 ml of 10 wt% aqueous solution of 4-methylphthalic acid, 28 ml of 0.5 mol / L sulfuric acid, Aerosol OT 5 ml of a 5% by weight aqueous solution (manufactured by American Cyanamid Co., Ltd.), 0.5 g of phenoxyethanol, and 0.1 g of benzoisothiazolinone are added to form a coating solution by adding water to a total amount of 750 g. I alum 26ml immediately before coating a mixture with a static mixer to 18.6 ml / m ² Was fed to a coating die so.
The viscosity of the coating solution was 20 [mPa · s] at a B-type viscometer of 40 ° C. (No. 1 rotor, 60 rpm).

4) Preparation of surface protective layer second layer coating liquid Surface protective layer second layer coating liquids -1 to 6 obtained in the preparation of the surface protective image second layer coating liquid of Example 1 were used.

3. Preparation of photothermographic material-501 to 510 Image forming layer coating solution-5, intermediate layer coating solution-C, surface protective layer first layer coating solution-2, surface protective layer second layer coating shown in Table 3 from undercoat surface Samples of the photothermographic material were prepared by simultaneous multilayer coating by the slide bead coating method in the order of any of liquids 1 to 6. At this time, the image forming layer coating solution and the intermediate layer coating solution were adjusted to 31 ° C., the surface protective layer first layer coating solution was adjusted to 36 ° C., and the surface protective layer second layer coating solution was adjusted to 37 ° C. The coated silver amount of the image forming layer was 0.821 g / m ² per side in total of the fatty acid silver and the silver halide. This was applied to both sides of the support.
The film thickness of the image forming layer was prepared to be 10 μm.
The coating amount (g / m ² ) per side of each compound in the image forming layer having a thickness of 10 μm is as follows.

Fatty acid silver 2.80
Polyhalogen compound-1 0.028
Polyhalogen compound-2 0.094
Silver iodide complex forming agent 0.46
SBR latex 5.20
Reducing agent-1 0.33
Reducing agent-2 0.13
Hydrogen bonding compound-1 0.15
Development accelerator-1 0.005
Development accelerator-2 0.035
Color tone adjusting agent-1 0.002
Mercapto Compound-1 0.001
Mercapto compound-2 0.003
Silver halide (as Ag) 0.146

The coating and drying conditions are as follows.
The coating was performed at a speed of 160 m / min, the gap between the coating die tip and the support was set to 0.10 to 0.30 mm, and the pressure in the decompression chamber was set to be 196 to 882 Pa lower than the atmospheric pressure. The support was neutralized with an ion wind before coating.
In the subsequent chilling zone, after cooling the coating solution with a wind at a dry bulb temperature of 10 to 20 ° C., it is transported in a non-contact type, and is dried at a dry bulb temperature of 23 to 45 ° C. It dried with the dry wind of the wet bulb temperature 15-21 degreeC.
After drying, the humidity was adjusted at 25 ° C. and humidity of 40 to 60% RH, and then the film surface was heated to 70 to 90 ° C. After heating, the film surface was cooled to 25 ° C.

  The photothermographic material thus prepared had a matte degree of Beck smoothness and the values shown in Table 3 on the image forming layer surface side. Further, the pH of the film surface on the image forming layer surface side was measured and found to be 6.0.

4). Evaluation of photographic performance The obtained sample was cut into half-cut size (43cm length x 35cm width), packaged in the following packaging materials in an environment of 25 ° C and 50%, stored at room temperature for 2 weeks, and then evaluated as follows. Went.
(Packaging material)
PE 50 μm containing PE 10 μm / PE 12 μm / aluminum foil 9 μm / Ny 15 μm / carbon 3% by mass.
Oxygen permeability: 0.02 ml / atm · m ² · 25 ° C · day, moisture permeability: 0.10 g / atm · m ² · 25 ° C · day.

The double-sided coated photosensitive material thus prepared was evaluated as follows.
An X-ray regular screen HI-SCREEN B3 (using CaWO ₄ as a phosphor, emission peak wavelength 425 m) manufactured by FUJIFILM Corporation is used, and a sample is sandwiched between them to produce an image forming assembly. did. This assembly was subjected to X-ray exposure for 0.05 seconds, and X-ray sensitometry was performed. The X-ray apparatus used was a trade name DRX-3724HD manufactured by Toshiba Corporation, and a tungsten target was used. A voltage of 80 kVp was applied to the three phases with a pulse generator, and X-rays passed through a 7 cm water filter having absorption equivalent to that of the human body were used as a light source. The exposure necessary for evaluation was performed by changing the X-ray exposure amount by the distance method. After the exposure, heat development was performed under the following heat development conditions. The obtained image was evaluated with a densitometer.

  The heat development unit of the Fuji Medical Dry Laser Imager FM-DPL was modified to produce a heat development machine that can be heated from both sides. In addition, the film was remodeled so that the film sheet could be conveyed by changing the conveyance roller of the heat developing unit to a heat drum. Four panel heaters were set to 112 ° C-118 ° C-120 ° C-120 ° C, and the temperature of the heat drum was set to 120 ° C.

  The photographic evaluation method is the same as in Example 1. The results are shown in Table 3.

  As shown in Table 3, also in the photosensitive material in which the image forming layer is provided on both sides of the support, the thickness of the image forming layer is 5 μm or more and 12 μm or less, and the diameter is 30% or more with respect to the thickness of the image forming layer. In the case of using the matting agent, a photothermographic material was obtained in which the granularity of the image quality was not deteriorated, the matting agent was hardly peeled off, the scratch resistance was excellent, and the light-sensitive material was hardly adhered.

Claims (9)

A photothermographic material having an image forming layer containing photosensitive silver halide, a non-photosensitive organic silver salt, a reducing agent and a binder on at least one surface of a support,
The film thickness of the image forming layer is 5 μm or more and 12 μm or less,
Any of the layers on the side having the image forming layer with respect to the support contains a matting agent having a diameter of 30% or more with respect to the film thickness of the image forming layer. . ^{2. The} photothermographic material according to claim 1, wherein the coating amount of the matting agent is 20 mg / m ² or more and 250 mg / m ² or less.   3. The photothermographic material according to claim 1, wherein the image forming layer is provided only on one side of the support.   3. The photothermographic material according to claim 1, wherein the image forming layer is provided on both sides of the support.   5. The photothermographic material according to claim 1, wherein the matting agent has a diameter of 30% to 120% of the film thickness of the image forming layer.   The photothermographic material according to claim 1, wherein the binder has a glass transition temperature of 0 ° C. or higher and 80 ° C. or lower. An image forming method of a photothermographic material according to any one of claims 1 to 6,
A method for forming an image of a photothermographic material, wherein the conveyance speed of the photothermographic material during heat development is 10 mm / second or more. An image forming method of a photothermographic material according to any one of claims 1 to 6,
An image forming method of a photothermographic material, wherein the photothermographic material is thermally developed while sliding.   8. The image forming method of a photothermographic material according to claim 7, wherein the photothermographic material is thermally developed while sliding.