JP2002296724A - Heat developable photosensitive material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat developable photosensitive material having low fog, high Dmax (maximum density) and improved physical characteristics after processing. SOLUTION: In the heat developable photosensitive material having at least one image forming layer on the base, a lower layer of a protective layer adjacent to the image forming layer on the image forming layer and at least one upper layer of the protective layer on the lower layer, the image forming layer contains a non-photosensitive organic silver salt, photosensitive silver halide, a reducing agent for silver ions and a binder, >=50 mass% of the binder in the image forming layer is a polymer latex having <=50 ppm NH4 <+> ion content based on the solid content and the I/O value of a binder in the lower layer of the protective layer given by dividing inorganic property value by organic property value basing on the organic conceptual diagram of the binder is larger than that of the binder in the image forming layer and smaller than that of a binder in the upper layer of the protective layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates is related to the heat development photosensitive material, a scanner particularly suitable for photomechanical,
More specifically, the present invention relates to a photothermographic material having low fog, a high Dmax (maximum density), and improved physical properties of a processed photographic material.

[0002]

2. Description of the Related Art A photosensitive image forming layer is provided on a support,
Many photosensitive materials that form an image by image exposure are known. Among them, there is a technique of forming an image by thermal development as a system that contributes to environmental conservation and can simplify an image forming unit. In recent years, so that the weight loss of the processing waste from the point of view of environmental protection and space saving is strongly desired in the photolithography field. Therefore, technical development of the photothermographic material of photolithography applications which can be a laser scanner or laser image setter can be efficiently exposed, and forming a clear black image having high resolution and sharpness is needed. According to such a photothermographic material, it is possible to supply a customer with a simpler and more environmentally friendly photothermographic processing system which does not require a solution processing chemical.

A method of forming an image by thermal development is described in, for example, US Pat. Nos. 3,152,904 and 3,4,904.
57,075, and D.C. Morgan
And B. "Thermally Processed Silver Systems" by Shely
A "(Imaging Purosesshizu-and-Materials (Imaging Processes and Materials) Neblette
Eighth Edition, Sturge, V. Wallwards (Wal
worth), A. Edited by Shepp, page 2, 196
9 years). Such photothermographic materials typically comprise a non-photosensitive reducible silver source (eg, an organic silver salt), a catalytically active amount of a photocatalyst (eg, silver halide), and a silver reducing agent dispersed in an organic binder matrix. It is contained in a state. The photosensitive material is stable at room temperature, but when heated to a high temperature (for example, 80 ° C. or higher) after exposure, silver is reduced through a redox reaction between a reducible silver source (which functions as an oxidizing agent) and a reducing agent. Generate This oxidation-reduction reaction is promoted by the catalytic action of the latent image formed by exposure. The silver formed by the reaction of the reducible silver salt in the exposed areas becomes black and forms an image because it contrasts with the unexposed areas.

Conventionally known photothermographic materials are:
In many cases, the image forming layer is formed by applying a coating solution using an organic solvent such as toluene, methyl ethyl ketone (MEK), or methanol as a solvent. The use of an organic solvent as a solvent not only adversely affects the human body in the manufacturing process, but also disadvantageous in cost because a solvent recovery and other steps are required.

Accordingly, a method has been proposed in which an image forming layer is formed by using a coating solution containing water as a solvent. For example, JP-A-49-52626, JP-A-53-116144
Japanese Patent Application Publication No. JP-A-2005-133125 describes an image forming layer using gelatin as a binder. JP-A-50-151138 describes an image forming layer using polyvinyl alcohol as a binder. Further, JP-A-60-617
No. 47 describes an image forming layer using a combination of gelatin and polyvinyl alcohol. As another example, JP-A-58-28737 describes an image forming layer using a water-soluble polyvinyl acetal as a binder. If such a binder is used, the image forming layer can be formed using a coating solution of a water solvent,
Environmental and cost benefits are significant.

However, when a hydrophilic polymer such as polyvinyl alcohol or water-soluble polyacetal is used as a binder for the image forming layer, the silver tone of the developed part becomes brown or yellow, which is far from black which is originally preferable, and the exposed part becomes dark. There was a problem that the blackening density was low and the density of the unexposed portion was high, and only those whose commercial value was significantly impaired could be obtained. On the other hand, when a hydrophilic polymer such as polyvinyl alcohol or a water-soluble polyacetal is used as a binder for the protective layer, the adhesiveness between the image forming layer and the upper protective layer after thermal development is significantly deteriorated, and the protective layer is easily peeled off. There was a problem. Furthermore, when a highly hydrophobic polymer latex is used as a binder for the protective layer, the adhesiveness of the image forming layer after thermal development can be obtained, but the compound added by thermal development elutes out of the film, and a white powdery There is a problem that stains (hereinafter, referred to as white powder) occur.

On the other hand, Japanese Patent Application Laid-Open No. 2000-26722
In JP-A-6, it is described that by defining the I / O value of the protective layer binder, the adhesion between the image forming layer and the protective layer after thermal development can be improved, and the generation of white powder in the exposed portion can be prevented. However, there is a problem that generation of white powder in the non-light-exposed area cannot be prevented. For this reason, the binder used in the above-mentioned aqueous solvent coating solution has low fog and Dmax.
It has been desired to provide a photothermographic material having a high (highest density), a high-contrast image, and improved physical properties of the processed photographic material.

[0008]

SUMMARY OF THE INVENTION A first object of the present invention is to provide a photolithography, especially a scanner,
An object of the present invention is to provide a photothermographic material for an image setter, which has a low fog, a high Dmax (maximum density), and an improved physical property of the processed photographic material. A second object of the present invention is to provide a photothermographic material which can be applied in water and which is advantageous in terms of environment and cost.

[0009]

Means for Solving the Problems The inventors of the present invention have made intensive studies to solve the above problems, and as a result, have at least one image forming layer on a support. In the photothermographic material having a protective lower layer adjacent thereto and further having at least one protective upper layer on the lower layer of the protective layer, the image forming layer has a non-photosensitive organic silver salt, a photosensitive silver halide, The image forming layer contains a reducing agent for silver ions and a binder.
When the mass% or more, the NH ₄ ⁺ ion content is 50 p
pm or less, and an I / O value obtained by dividing an inorganic value based on an organic conceptual diagram of the binder in the lower layer of the protective layer by an organic value is smaller than the I / O value of the binder in the image forming layer. The photothermographic material according to the invention, which is large and is smaller than the I / O value of the binder in the upper layer of the protective layer, has been provided. The photothermographic material of the present invention preferably contains a polymer latex as a binder for the lower layer of the protective layer and the upper layer of the protective layer.
Further, by adding a compound capable of forming a development start point in the vicinity of the non-photosensitive organic silver salt to the image forming layer in an image-wise manner at 0.01 mol / silver mol, the density of the developed silver particles becomes 200 to It is preferable to include at least one compound that increases to 5000% or a compound whose covering power increases to 120 to 1000% when added at 0.01 mol / silver mol. Further, it is preferable to have a layer containing a metal oxide on at least one surface of the support, and a vinylidene chloride copolymer containing at least 70% by mass of a repeating unit of vinylidene chloride monomer on both surfaces of the support. It is preferable to have an undercoat layer.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
In this specification, “to” indicates a range including numerical values described before and after the range as a minimum value and a maximum value, respectively.

The photothermographic material of the present invention has at least one image forming layer on a support, has a protective layer lower layer adjacent to the image forming layer, and further has a protective layer lower layer. A layer configuration having at least one upper protective layer is adopted. The image forming layer of the present invention contains at least a non-photosensitive organic silver salt, a photosensitive silver halide, a reducing agent for silver ions, and a binder, and preferably forms a development start point near the non-photosensitive organic silver salt. Compound that generates possible species in an image-wise manner, 0.01 mol / silver mol
To give a developed silver particle density of 200 to 500.
By adding the compound increasing to 0% at 0.01 mol / silver mol, the covering power becomes 120 to 100.
Contains compound increasing to 0%. Further, 50% by mass or more of the binder in the image forming layer is a polymer latex having an NH ₄ ⁺ ion content of 50 ppm or less with respect to the solid content. The I / O value divided by the value is larger than the I / O value of the binder in the image forming layer and smaller than the I / O value of the binder in the upper layer of the protective layer. In the present invention, it is preferable to use a polymer latex not only as the binder for the protective layer but also for the image forming layer.

In the photothermographic material of the present invention, by adopting the above-mentioned constitution, the adhesion between the image forming layer and the protective layer is good even after the heat development, and the photothermographic material can be used regardless of the presence or absence of light exposure. , The generation of white powder can be prevented. On the other hand, if the NH ₄ ⁺ ion content of the binder in the image forming layer exceeds 50 ppm based on the solid content, it is not possible to prevent the generation of white powder in the non-light-exposed area. On the other hand, the I / O value of the binder under the protective layer is
When the value is not between the value and the I / O value of the binder in the upper layer of the protective layer, the generation of white powder cannot be prevented not only in the non-light-exposed portion but also in the light-exposed portion. The I / O value will be described later.

At least one of the image forming layers of the present invention comprises at least one of the polymer latex described below and 5
The image forming layer was used in an amount of 0% by mass or more. (Or later,
This image forming layer is referred to as “the image forming layer of the present invention”, and the polymer latex used for the binder is referred to as “the polymer latex of the present invention”. In addition, the polymer latex may be used not only for the image forming layer but also for the protective layer and the back layer. In particular, when the photothermographic material of the present invention is used for printing in which dimensional change is problematic, It is preferable to use a polymer latex also for the back layer.

However, the "polymer latex" mentioned here
The term “water-insoluble hydrophobic polymer” means fine particles of a water-insoluble hydrophobic polymer dispersed in a water-soluble dispersion medium. The dispersion state is such that the polymer is emulsified in a dispersion medium, emulsion-polymerized, micelle-dispersed, or partially dispersed in polymer molecules and the molecular chains themselves are molecularly dispersed. Any of them may be used. The polymer latex used in the present invention is described in "Synthetic Resin Emulsion (Taira Okuda, edited by Hiroshi Inagaki, published by Kobunshi Kankokai (197
8))), "Applications of Synthetic Latex (Edited by Takaaki Sugimura, Yasuo Kataoka, Soichi Suzuki, Keiji Kasahara, Polymer Publishing Association (19)
93)) "," Synthesis of Synthetic Latex (Souichi Muroi, published by Kobunshi Kankokai (1970)) "and the like. The average particle size of the dispersed particles is preferably in the range of about 1 to 50,000 nm, more preferably about 5 to 1,000 nm. There is no particular limitation on the particle size distribution of the dispersed particles, and they may have a broad particle size distribution or a monodispersed particle size distribution.

The polymer latex of the present invention may be a so-called core / shell type latex other than a polymer latex having a normal uniform structure. In this case the core and shell may be preferred when different glass transition temperature.
In particular, a core / shell type latex in which the Tg of the core is higher than the Tg of the shell provides good film-forming properties.

The glass transition temperature (Tg) of the polymer latex used in the binder of the present invention is preferably different between the protective layer, the back layer and the image forming layer. In the image forming layer, to promote diffusion of useful photographic materials during thermal development,
30-40 ° C. When used for a protective layer or a back layer, a glass transition temperature of 25 to 100 ° C. is preferable for contacting various devices. The Tg of the polymer is, for example, "J. Br
andrup, EHImmergut co-authored Polymer Handbook, 2nd Editio
n, III-139 to III-192 (1975) ".

The minimum film forming temperature (MFT) of the polymer latex used in the present invention is preferably from -30 ° C to 90 ° C, more preferably from about 0 ° C to 70 ° C. A film-forming aid may be added to control the minimum film-forming temperature. The film forming aid is an organic compound (usually an organic solvent) which is also called a plasticizer and lowers the minimum film forming temperature of the polymer latex. )"It is described in.

The content of NH ₄ ⁺ ions in the polymer latex of the present invention is 50 ppm or less based on the solid content.
0 ppm or less is more preferable, and 10 ppm or less is further preferable.

The NH ₄ ⁺ ions in the latex are mainly brought in by using (NH ₄ ) ₂ S ₂ O ₈ as a polymerization initiator or by using NH ₄ OH as a pH adjuster after the polymerization reaction. The NH ₄ ⁺ ions introduced into the latex have an adverse effect on the dispersion state of the coating liquid for the image forming layer of the photothermographic material of the present invention, or remain in the photothermographic material even after coating and drying, and during thermal development. It evaporates as ammonia during storage and adversely affects the storage stability of the photothermographic material. Further, although the mechanism is unknown, it has been clarified in the present invention that it is involved in the generation of white powder after thermal development. Therefore, K ₂ S ₂ O ₈ is used as a polymerization initiator.
Or Na ₂ S ₂ O ₈ is preferably used, and KOH or NaOH is preferably used as a pH adjuster.

The determination of NH ₄ ⁺ ions in the latex was carried out by using a Tosoh TSK 8000 type ion chromatograph (electric conductivity method) and a separation column.
gelIC-Cation, TS as a guard column
The measurement was performed using K guard column IC-C. As the eluent, a 2 mM nitric acid aqueous solution was used.
The test was performed at a flow rate of 1 / min. The temperature of the column was set at 40 ° C.

The extraction of NH ₄ ⁺ ions from the latex is
1 g of latex and 3 g of ion-exchanged water are mixed, and about 2.5 ml of the mixture is put into a cut-off filter (pore size: 5 μm) manufactured by Sartorius AG, and centrifugal separator CR22 manufactured by Hitachi Koki Co., Ltd. at 3500 rpm, 25
Centrifugation at 2 ° C. for 2 hours, and appropriately diluting the clear supernatant obtained by centrifugation with ion-exchanged water according to the NH ₄ ⁺ ion content of the sample (eg, 10-fold dilution, 100-fold dilution) )It was measured.

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

Specific examples of the polymer latex used as a binder for the image forming layer of the photothermographic material of the present invention include methyl methacrylate / ethyl acrylate / methacrylic acid copolymer latex, methyl methacrylate / butadiene / itaconic acid copolymer latex. Latex of ethyl acrylate / methacrylic acid copolymer, latex of methyl methacrylate / 2-ethylhexyl acrylate / styrene / acrylic acid copolymer, latex of styrene / butadiene / acrylic acid copolymer, latex of styrene / butadiene / divinylbenzene / methacrylic acid copolymer, methyl Latex of methacrylate / vinyl chloride / acrylic acid copolymer, vinylidene chloride / ethyl acrylate / acrylonitrile / Such as latex of methacrylic acid copolymers. More specifically, methyl methacrylate / ethyl acrylate / methacrylic acid = 33.5.
/50/16.5 (% by mass) copolymer latex,
Methyl methacrylate / butadiene / itaconic acid = 4
Examples thereof include a copolymer latex of 7.5 / 47.5 / 5 (% by mass) and a copolymer latex of ethyl acrylate / methacrylic acid = 95/5 (% by mass). These polymers may be used alone or, if necessary,
More than one kind may be blended and used.

The total amount of the binder in the image forming layer of the present invention is 0.2 to 30 g / m ² , more preferably 1 to 15 g / m ^2.
Is preferable. A crosslinking agent for crosslinking, a surfactant for improving coating and the like may be added to the image forming layer of the invention.

A hydrophilic polymer such as gelatin, polyvinyl alcohol, methylcellulose, hydroxypropylcellulose, carboxymethylcellulose and hydroxypropylmethylcellulose may be added to the image forming layer if necessary in a range of 50% by mass or less of the whole binder. . The addition amount of these hydrophilic polymers is preferably 30% by mass or less, more preferably 15% by mass or less based on the total binder of the image forming layer.

The image forming layer is preferably prepared by applying an aqueous coating solution and then drying. However, the term “aqueous” as used herein means that 60% by mass or more of the solvent (dispersion medium) of the coating liquid is water. Components other than water in the coating solution are methyl alcohol, ethyl alcohol, isopropyl alcohol,
Water-miscible organic solvents such as methyl cellosolve, ethyl cellosolve, dimethylformamide, and ethyl acetate can be used. Specific examples of the solvent composition include the following. Water / methanol = 90/10, water / methanol = 70/30, water / ethanol = 90/10,
Water / isopropanol = 90/10, water / dimethylformamide = 95/5, water / methanol / dimethylformamide = 80/15/5, water / methanol / dimethylformamide = 90/5/5. (However, the numbers represent mass%.)

The protective layer of the present invention is composed of two or more layers, and the I / O value of the polymer of the protective layer (the lower layer of the protective layer) adjacent to the image forming layer is determined by the I / O value of the binder of the image forming layer. Value and smaller than the I / O value of the protective layer. The I / O value of the polymer binder under the protective layer is
0.15 to 0.60 is preferable, and 0.35 to 0.55 is particularly preferable. Note that the upper layer of the protective layer is usually an upper layer adjacent to the lower layer of the protective layer because a protective layer having a two-layer structure is often used. Further, the polymer binder of the protective layer refers to the main binder, and occupies 75% by mass or more of the entire binder. When two or more such polymer binders are mixed to form the main binder, all the polymer binders need to satisfy the above relationship.

The I / O value of the polymer used as the binder of the protective layer in the present invention, that is, the value obtained by dividing the inorganic value based on the organic conceptual diagram by the organic value, is referred to as "organic conceptual diagram-basics and applications-, Koda" Yoshio, published by Sankyo Publishing (1984) "
Can be determined by the method described in (1).

Here, the organic conceptual diagram divides the properties of a compound into an organic value indicating covalent bonding and an inorganic value indicating ionic bonding, and all organic compounds are named as an organic axis and an inorganic axis. Inorganic values based on these values are indicated by one point on the orthogonal coordinates, and the inorganic value based on this is defined as inorganic, that is, the magnitude of the influence of various substituents on the boiling point is determined based on the hydroxyl group, Is about 100 ° C. when the distance between the boiling point curve and the boiling point curve of the normal paraffin is taken in the vicinity of carbon number 5, the influence of one hydroxyl group is set to 100 numerically. On the other hand, the organic value means that the magnitude of the organic value can be measured in units of a methylene group in the molecule and can be measured by the number of carbon atoms representing the methylene group.
Is the average value of the boiling point increase by adding one carbon in the vicinity of 5 to 10 carbon atoms of the straight-chain compound, 20 ° C.,
The value is set to 20 based on this. The inorganic value and the organic value are determined so as to correspond one to one on the graph. The I / O value is calculated from these values.

As the binder for the protective layer of the present invention,
Of the above-mentioned polymer latexes, acrylic, styrene, acryl / styrene, vinyl chloride and vinylidene chloride are preferably used.

Specific compounds are shown below, but the present invention is not limited to the following compounds. (The composition ratio is% by mass and MW is the weight average molecular weight.) Pol-1 methyl methacrylate / isobutyl acrylate = 52/48 (MW = 750,000) Pol-2 methyl methacrylate / n-butyl acrylate = 66 / 34 (MW = 550,000) Pol-3 Ethyl methacrylate / n-butyl acrylate = 67/33 (MW = 800,000) Pol-4 Methyl methacrylate / ethyl acrylate = 52/48 (MW = 700,000) Pol- 5 n-butyl methacrylate / isobutyl methacrylate = 68/32 (MW = 900,000) Pol-6 methyl methacrylate / methyl acrylate = 30/70 (MW = 700,000) Pol-7 methyl methacrylate / 2-ethylhexyl acrylate / Styrene / hydroxyethyl methacrylate / acrylic acid = 58/26/9/5/2 (MW
= 350,000) Pol-8 Methyl methacrylate / styrene / butyl acrylate / hydroxyethyl methacrylate / acrylic acid = 56/9/28/5/2 (MW = 400,0)
00) Pol-9 ethyl methacrylate / 2-ethylhexyl acrylate = 78/22 (MW = 450,00
0) Pol-10 methyl methacrylate / styrene / methyl acrylate = 10/33/57 (MW = 500,0
00) Pol-11 n-butyl methacrylate / s-butyl methacrylate = 73/27 (MW = 850,000) Pol-12 methyl methacrylate / methyl acrylate / acrylic acid = 26/70/4 (MW = 1400,
000) Pol-13 methyl methacrylate / butyl acrylate / acrylic acid = 71/27/2 (MW = 900,0
00) Pol-14 styrene / butyl acrylate = 64 /
36 (MW = 650,000) Pol-15 Styrene = 100 (MW = 700,00
0) The total binder amount (per layer) of the protective layer in the photothermographic material of the present invention is preferably from 0.2 to 10.0 g / m ² , more preferably from 1.0 to 5.0 g / m ² . preferable.
A surfactant or the like for improving coating properties may be added to the protective layer. The pH of the coating solution for the protective layer is preferably 5 to 8 for the lower layer and 2 to 7 for the upper layer.

In the present invention, if necessary,
Nos. 00-267226, Paragraph Nos. 0021-002
5 plasticizer (for example, benzyl alcohol, 2,
2,4-trimethylpentanediol-1,3-monoisobutyrate) can be added to control the film formation temperature. Further, Japanese Patent Application Laid-Open No. 2000-26722
As described in Paragraph Nos. 0027 to 0028 of JP-A-6, a hydrophilic polymer may be added to a polymer binder, and a water-miscible organic solvent may be added to a coating solution.

Each layer is described in JP-A-2000-196.
Use of a first polymer latex having a functional group introduced therein and a crosslinking agent having a functional group capable of reacting with the first polymer latex and / or a second polymer latex described in paragraph Nos. You can also. The functional group is a carboxyl group, a hydroxyl group, an isocyanate group, an epoxy group, an N-methylol group, an oxazolinyl group, and the like.As a crosslinking agent, an epoxy compound, an isocyanate compound, a blocked isocyanate compound, a methylol compound, a hydroxy compound, It is selected from a carboxyl compound, an amino compound, an ethyleneimine compound, an aldehyde compound, a halogen compound and the like. Specific examples of the cross-linking agent include hexamethylene isocyanate and duranate WB4 as isocyanate compounds.
0-80D, WX-1741 (manufactured by Asahi Kasei Corporation),
Bayhijur 3100 (Sumitomo Bayer Urethane Co., Ltd.)
Manufactured), Takenate WD725 (Takeda Pharmaceutical Co., Ltd.)
Aquanate 100, 200 (manufactured by Nippon Polyurethane Co., Ltd.), water-dispersible polyisocyanate described in JP-A-9-160172; Sumitex Resin M-3 as an amino compound (manufactured by Sumitomo Chemical Co., Ltd.) As an epoxy compound, Denacol EX-614B (manufactured by Nagase Kasei Kogyo); as a halogen compound, 2,4-dichloro-
6-hydroxy-1,3,5-triazine sodium and the like.

By adding a compound capable of forming a development start point in the vicinity of the non-photosensitive organic silver salt used in the present invention in an image-wise manner at 0.01 mol / silver mol, the density of developed silver particles can be reduced. A compound that increases to 200 to 5000% and a compound that increases the covering power to 120 to 1000% when added at 0.01 mol / silver mol will be described. First, a compound that generates a chemical species capable of forming a development start point in the vicinity of a non-photosensitive organic silver salt in an image-wise manner will be described. When the compound is not present in the light-sensitive material, physical development proceeds only on the silver halide on which a latent image has been formed by exposure.
When a compound of the formula (1) is present in the photosensitive material, the chemical species generated with physical development occurring on the silver halide on which the latent image has been formed by exposure to light, for example, a compound with an oxidized developing agent reacts and becomes non-photosensitive. A chemical species capable of forming a development start point is generated near the organic silver salt. The chemical species forms a development starting point near the non-photosensitive silver salt, for example, silver behenate, from which physical development occurs. That is, when the compound is present in the light-sensitive material, physical development can be performed both on the silver halide on which the latent image has been formed by exposure and near the non-photosensitive organic silver salt on which the image-wise development start point has been formed. proceed. As a specific example of such an effect, Japanese Patent Application No.
Reference can be made to the description of FIG. 1 and [0010] of JP-A-395037.

Next, compounds which increase the density of developed silver particles to 200 to 5000% by adding 0.01 mol / mol of silver will be described. The increase in the density of developed silver particles can be obtained by taking a photograph of a sample in which all silver ions in the photosensitive material have been reduced, counting the number of developed silver particles per unit area, and comparing the densities. it can. When the compound of the present invention is present in the photosensitive material,
The density of developed silver particles is increased to 200 to 5000% as compared with the case where the compound (1) is not present in the light-sensitive material. A more preferred compound has a developed silver particle density increase rate of 500 to 3000.
%.

Next, by adding at 0.01 mol / silver mol, the covering power becomes 120-1000%.
The compound which increases to will be described. As used herein, the term "covering power" refers to a value obtained by dividing the visible density by the amount of developed silver (g / m ² ) for a sample in which all silver ions in the photosensitive material have been reduced. The increase in covering power by the compounds of the present invention is due to the formation of many smaller developed silver particles. The covering power of the compound is more preferably from 150 to 500%.

Next, as specific examples of the compound corresponding to any of the above-mentioned, hydrazine derivatives represented by the formula (H) described in JP-A-2000-284399 (specifically, Table 1 of the same publication) ~ Hydrazine derivatives described in Table 4), JP-A-10-10672, JP-A-10-1
61270, JP-A-10-62898, JP-A-9-304870, JP-A-9-304872
JP-A-9-304871, JP-A-9-304871,
No. 31282, U.S. Pat. No. 5,496,695, all hydrazine derivatives described in EP 741,320A, JP-A-2000-2843.
No. 99, the substituted alkene derivatives represented by the formulas (1) to (3), the substituted isoxazole derivative and a specific acetal compound, and further the formula (A) described in the same publication
Or the cyclic compound represented by the formula (B), specifically, compounds 1 to 72 described in Chemical formulas 8 to 12 of the publication can be mentioned. Further, as the compound corresponding to any of the above, the compound of the formula (2) described in Japanese Patent Application No. 2000-76240, specifically, the compound (I) described in the publication
I-1) to (II-118) are also preferably used.

As the compound corresponding to any of the following items used in the present invention, a compound represented by the general formula (1) described in JP-A-11-149136 is more preferably used. Specific examples of the compound represented by the general formula (1) are shown below.

[0039]

[Table 1]

[0040]

[Table 2]

[0041]

[Table 3]

[0042]

[Table 4]

[0043]

[Table 5]

[0044]

[Table 6]

[0045]

[Table 7]

[0046]

[Table 8]

[0047]

[Table 9]

[0048]

[Table 10]

[0049]

[Table 11]

[0050]

[Table 12]

Further, formic acid precursors described in Japanese Patent Application No. 2000-313207 are also preferably used. Specific examples of the compound are shown below.

[0052]

Embedded image

Compounds corresponding to any of the following may be water or a suitable organic solvent such as alcohols (methano-
, Ethanol, propanol, fluorinated alcohol
), Ketones (acetone, methyl ethyl ketone), dimethylformamide, dimethylsulfoxide, methylcellosolve and the like. Further, oils such as dibutyl phthalate, tricresyl phosphate, glyceryl triacetate or diethyl phthalate can be prepared by a well-known emulsification dispersion method.
It can be dissolved using an auxiliary solvent such as ethyl acetate or cyclohexanone to mechanically prepare and use an emulsified dispersion. Alternatively, the powder of the compound corresponding to any of the following may be dispersed in a suitable solvent such as water by ball mill, colloid mill or ultrasonic wave by a method known as a solid dispersion method, and used.

The compound corresponding to any of the following:
Only one kind may be used, or two or more kinds may be used in combination. ~of
Compounds that fall into any of the categories form an image on the support
Although it may be added to any layer on the layer side, it may be added to the image forming layer.
Or it is preferably added to a layer adjacent thereto.
The amount of the compound corresponding to any of the above is 1 mol of silver
1 × 10^-6１1 mol is preferable, and 1 × 10^-Five~
5 × 10^-1mol is more preferable, and 2 × 10 ^-Five~ 2 × 1
0^-1mol is most preferred.

In the photothermographic material of the present invention, an acid or a salt thereof formed by hydration of diphosphorus pentoxide is preferably used in combination with a nucleating agent. Acids or salts thereof formed by hydration of diphosphorus pentoxide include metaphosphoric acid (salt), pyrophosphoric acid (salt), orthophosphoric acid (salt), triphosphoric acid (salt), tetraphosphoric acid (salt), hexametaline Acids (salts) and the like can be mentioned. Particularly preferred acids and salts thereof formed by hydration of diphosphorus pentoxide include orthophosphoric acid (salt) and hexametaphosphoric acid (salt). Specific salts include sodium orthophosphate, sodium dihydrogen orthophosphate, sodium hexametaphosphate, and ammonium hexametaphosphate. The acid or salt thereof formed by hydration of diphosphorus pentoxide, which can be preferably used in the present invention, is added to the image forming layer or the binder layer adjacent thereto in that a desired effect is exhibited in a small amount. Use amount of the oxidizing acid or salt thereof formed by hydration of diphosphorus (coating amount per photographic material 1 m ²⁾ may be a desired amount depending on the performance such as sensitivity and fog, but, 0.1 to 500 mg / m ² is preferred, and 0.5 to
100 mg / m ² is more preferred.

The organic silver salt that can be used in the present invention includes:
Relatively stable to light, but forms a silver image when heated to 80 ° C. or higher in the presence of an exposed photocatalyst (such as a latent image of a photosensitive silver halide) and a reducing agent. It is a silver salt. The organic silver salt can be any organic material including a source of reducible silver ions. Silver salts of organic acids,
Particularly (having 10 to 30 carbon atoms, preferably 15 to 28 carbon atoms)
Silver salts of long chain fatty carboxylic acids are preferred. The ligand is 4.0
Complexes of organic or inorganic silver salts having a complex stability constant in the range of from 10.0 to 10.0 are also preferred. The silver donor material can preferably comprise about 5 to 70% by weight of the imaging layer. Preferred organic silver salts include silver salts of organic compounds having a carboxyl group. In particular,
Examples thereof include, but are not limited to, silver salts of aliphatic carboxylic acids and silver salts of aromatic carboxylic acids. Preferred examples of the silver salt of an aliphatic carboxylic acid include:
Silver behenate, silver arachidate, silver stearate, silver oleate, silver laurate, silver caproate, silver myristate, silver palmitate, silver maleate, silver fumarate, silver tartrate, silver linoleate, silver butyrate and Silver camphorate and mixtures thereof can be mentioned.

In the present invention, among the above-mentioned organic acid silver or a mixture of the organic acid silver, a silver behenate content of 75 m
ol% or more of organic acid silver, more preferably 85% by mole or more of silver behenate. Here, the content of silver behenate indicates the mole fraction of silver behenate with respect to the organic acid silver used. As the organic acid silver other than silver behenate contained in the organic acid silver used in the present invention, the above-mentioned exemplified organic acid silver can be preferably used.

The organic silver salt preferably used in the present invention is
It is prepared by reacting silver nitrate with a solution or suspension of the above-mentioned alkali metal salt of an organic acid (including Na salt, K salt, Li salt and the like). These preparation methods are described in JP-A-2000-292882, paragraph number 00.
The methods described in 19 to 0021 can be used.

In the present invention, a method of preparing an organic silver salt by adding an aqueous solution of silver nitrate and a solution of an alkali metal salt of an organic acid into a sealing means for mixing liquids can be preferably used. Specifically, JP-A-200
The method described in 1-333907 can be used. In the present invention, a water-soluble dispersant can be added to the aqueous silver nitrate solution and the organic acid alkali metal salt solution or the reaction solution during the preparation of the organic acid silver.
Specific examples of the type and amount of the dispersant used here are described in JP-A-2000-305214, paragraph 0052.

The organic acid silver used in the present invention is preferably prepared in the presence of a tertiary alcohol. As the tertiary alcohol, a compound having a total carbon number of 15 or less is preferable, and a compound having a total carbon number of 10 or less is particularly preferable. Preferred examples of the tertiary alcohol include tert-butanol, but the tertiary alcohol that can be used in the present invention is not limited to this. The tertiary alcohol used in the present invention may be added at any time during the preparation of the organic acid silver salt.
It is preferable to dissolve and use the organic acid alkali metal salt. Further, the tertiary alcohol used in the present invention is 0.01 to 1 in mass ratio to water as a solvent at the time of preparing the silver salt of an organic acid.
Although it can be used in the range of 0, it is preferable to use in the range of 0.03-1.

The shape and size of the organic silver salt which can be used in the present invention are not particularly limited.
It is preferable to use those described in paragraphs 0024 of JP-2882. The shape of the organic silver salt can be determined from a transmission electron microscope image of the organic silver salt dispersion. Another method for measuring monodispersity is to determine the standard deviation of the volume-weighted average diameter of the organic silver salt. The percentage (coefficient of variation) divided by the volume-weighted average diameter is preferably 80% or less, more preferably Preferably not more than 50%, more preferably 30%
% Or less. As a measuring method, for example, an organic silver salt dispersed in a liquid is irradiated with laser light, and the particle size (volume weighted average diameter) obtained by obtaining an autocorrelation function with respect to a time change of fluctuation of the scattered light is obtained. be able to. 0 The average particle size in this assay.
A solid fine particle dispersion of from 0.05 μm to 10.0 μm is preferred. A more preferred average particle size is 0.1 μm to 5.0.
μm, more preferably the average particle size is 0.1 μm to
2.0 μm.

The organic silver salt used in the present invention is preferably desalted. The desalting method is not particularly limited, and a known method can be used, but centrifugal filtration, suction filtration,
Known filtration methods such as ultrafiltration and floc-forming water washing by a coagulation method can be preferably used. As a method for ultrafiltration, a method described in JP-A-2000-305214 can be used.

In the present invention, in order to obtain an organic silver salt solid dispersion having a high S / N, a small particle size and no aggregation, an organic silver salt which is an image forming medium and a photosensitive silver salt are substantially contained. It is preferable to use a dispersion method in which a water dispersion liquid which is not included in the liquid is converted into a high-speed flow and then the pressure is reduced. As for these dispersing methods, the methods described in paragraphs 0027 to 0038 of JP-A-2000-292882 can be used.

The particle size distribution of the organic silver salt solid fine particle dispersion used in the present invention is preferably monodispersed. Specifically, the percentage (coefficient of variation) of the value obtained by dividing the standard deviation of the volume load average diameter by the volume load average diameter is 80% or less, more preferably 50% or less, and still more preferably 30% or less.

The organic silver salt solid fine particle dispersion used in the present invention comprises at least an organic silver salt and water. The ratio between the organic silver salt and water is not particularly limited, but the ratio of the organic silver salt to the whole is preferably 5 to 50% by mass, and particularly preferably 10 to 30% by mass.
It is preferable to use the above-mentioned dispersing aid, but it is preferable to use the dispersing aid in a minimum amount within a range suitable for minimizing the particle size.
A range of 15% by mass is preferred.

The organic silver salt used in the present invention can be used in a desired amount, but the silver amount is preferably 0.1 to 5 g / m ² ,
More preferably, it is 1-3 g / m < ² >.

In the present invention, it is preferable to add a metal ion selected from Ca, Mg, Zn and Ag to the non-photosensitive organic silver salt. Regarding addition of metal ions selected from Ca, Mg, Zn and Ag to the non-photosensitive organic silver salt,
It is preferably added in the form of a water-soluble metal salt which is not a halide, and specifically, it is preferably added in the form of a nitrate or a sulfate. The addition of a halide is not preferable because it deteriorates the image storability of the processed photosensitive material due to light (such as room light or sunlight), that is, the so-called printout property. For this reason, in the present invention, it is preferable to add in the form of a water-soluble metal salt which is not a halide.

Ca, Mg, Zn preferably used in the present invention
The addition time of the metal ion selected from Ag and Ag may be any time after the formation of the particles of the non-photosensitive organic silver salt and immediately before the coating, such as immediately after the formation of the particles, before the dispersion, after the dispersion and before and after the preparation of the coating solution. It may be during the period, preferably after dispersion and before and after preparation of the coating solution.

In the present invention, Ca, Mg, Zn and A
The addition amount of the metal ion selected from g is preferably 10 ^-3 to 10 ^-1 mol, particularly preferably 5 × 10 ^{-3 to} 5 × 10 ^-2 mol, per 1 mol of non-photosensitive organic silver.

The photosensitive silver halide used in the present invention is not particularly limited in terms of the halogen composition.
Silver bromide, silver iodobromide, silver iodochlorobromide can be used. The grain formation of the photosensitive silver halide emulsion is described in paragraphs 0217 to 0217 of JP-A-11-119374.
The particles can be formed by the method described in H.224, but are not particularly limited to this method. The shapes of silver halide grains are cubic, octahedral, tetradecahedral,
Tabular, spherical, rod-like, potato-like and the like can be mentioned, and in the present invention, cubic particles or tabular particles are particularly preferable. The characteristics of the particle shape such as the particle aspect ratio and the surface index are described in JP-A-11-119374.
It is the same as that described in Paragraph No. 0225 of the publication. The distribution of the halogen composition may be uniform inside and on the surface of the silver halide grains, and the halogen composition may be changed stepwise or may be changed continuously. Further, silver halide grains having a core / shell structure can be preferably used.
As the structure, core / shell particles having preferably a 2- to 5-layer structure, more preferably a 2- to 4-layer structure, can be used. A technique for localizing silver bromide on the surface of silver chloride or silver chlorobromide grains can also be preferably used.

The size of the silver halide grains of the photosensitive silver halide used in the present invention can be used without any particular limitation, but is preferably 0.12 μm or less,
It is preferably from 0.1 to 0.10 μm. The particle size distribution of the silver halide grains used in the present invention is such that the value of monodispersity is 30% or less, preferably 1 to 20%, and more preferably 5 to 15%.
It is. Here, the monodispersity is defined as a percentage (%) (coefficient of variation) of a value obtained by dividing the standard deviation of the particle size by the average particle size. For the sake of convenience, the grain size of silver halide grains is represented by a ridge length in the case of cubic grains, and other grains (octahedral, tetradecahedral, tabular, etc.) are calculated by projected area circle equivalent diameters.

Photosensitive silver halide grains used in the present invention
Is a metal of Group VII or VIII of the Periodic Table
Or it contains a metal complex. Group VII of the periodic table
Or a central metal of a Group VIII metal or metal complex.
And preferably rhodium, rhenium, ruthenium, osuni
And iridium. Particularly preferred metal complexes are
(NH_Four)_ThreeRh (H_TwoO) Cl_Five, K_TwoRu (NO) C
l_Five, K_ThreeIrCl₆, K_FourFe (CN)₆It is. These gold
The complex of the genus may be of one kind,
Two or more complexes may be used in combination. The preferred content is silver 1
1 × 10 per mol ^-9mol ~ 1 × 10^-3mol range
Enclosure is preferred, 1 × 10^-8mol ~ 1 × 10^-Fourmol
The range is more preferred. Specific structures of metal complexes include
Gold having a structure described in JP-A-7-225449 and the like
A genus complex can be used. Types of heavy metals,
Regarding the adding method, see Japanese Patent Application Laid-Open No. 11-119374.
Paragraph numbers 0227 to 0240 are described.

The photosensitive silver halide grains can be desalted by a water washing method known in the art such as a noodle method or a flocculation method, but in the present invention, it may or may not be desalted. . The photosensitive silver halide emulsion used in the present invention is preferably chemically sensitized. The chemical sensitization is described in paragraph No. 02 of JP-A-11-119374.
It is preferable to use the methods described in JP-A Nos. 42-0250. The silver halide emulsion used in the present invention is prepared by the method described in EP-A-293,917.
A thiosulfonic acid compound may be added.

As the gelatin contained in the photosensitive silver halide used in the present invention, low molecular weight gelatin is used in order to maintain a good dispersion state of the photosensitive silver halide emulsion in the coating solution containing an organic silver salt. Is preferred. The low molecular weight gelatin has a molecular weight of 500 to 60,000, preferably 1,000 to 40,000. These low molecular weight gelatins may be used at the time of particle formation or at the time of dispersion after desalting, but are preferably used at the time of dispersion after desalting. When forming particles, use normal gelatin (molecular weight of about 100,000),
Low-molecular-weight gelatin may be used at the time of dispersion after desalting.

The concentration of the dispersion medium can be 0.05 to 20% by mass, but a concentration range of 5 to 15% by mass is preferable for handling. As the type of gelatin, alkali-treated gelatin is usually used, and in addition, acid-treated gelatin,
Modified gelatin such as phthalated gelatin can also be used.

As the silver halide emulsion in the light-sensitive material used in the present invention, only one type may be used, or two or more types may be used (for example, those having different average grain sizes, different halogen compositions, different crystal habits). And those having different chemical sensitization conditions).

The amount of the photosensitive silver halide used in the present invention is preferably 0.01 mol to 0.5 mol, and more preferably 0.02 mol to 1 mol of the organic silver salt.
mol to 0.3 mol, more preferably 0.03 mol
~ 0.25 mol is particularly preferred. About the mixing method and mixing conditions of the separately prepared photosensitive silver halide and organic silver salt, the silver halide particles and the organic silver salt which have been respectively prepared are mixed with a high-speed stirrer, a ball mill, a sand mill, a colloid mill, a vibration mill, There is a method of mixing with a homogenizer or the like, or a method of preparing an organic silver salt by mixing photosensitive silver halide prepared at any timing during the preparation of the organic silver salt. There is no particular limitation as long as it is sufficiently obtained. In addition, mixing two or more kinds of aqueous dispersions of organic silver salts and two or more kinds of aqueous dispersions of photosensitive silver salts is a preferable method for adjusting photographic characteristics.

Sensitizing dyes that can be used in the present invention are those capable of spectrally sensitizing silver halide grains in a desired wavelength region when adsorbed on silver halide grains, and are suitable for the spectral characteristics of an exposure light source. Sensitizing dyes having spectral sensitivity can be advantageously selected. For example, 550 nm to 750 n
As a dye for spectrally sensitizing a wavelength region of m
And dyes represented by the general formula (II) of JP-A-186572, specifically, II-6, II-7, and II-1.
4, II-15, II-18, II-23, II-25
Can be exemplified as preferred dyes. Examples of the dye that spectrally sensitizes the wavelength region of 750 to 1400 nm include a dye represented by the general formula (I) in JP-A-11-119374.
5), (26), (30), (32), (36), (3)
The dyes of 7), (41), (49) and (54) can be exemplified as preferred dyes. Furthermore, J-ban
US Pat. No. 5,510,23 as a dye forming d.
And the dyes described in Example 5 of JP-A Nos. 6,871,887 and JP-A-2-96131 and JP-A-59-48753 are preferred dyes. Examples can be given. These sensitizing dyes may be used alone or in combination of two or more.

These sensitizing dyes can be added by the method described in paragraph No. 0106 of JP-A-11-119374, but it is not particularly limited to this method. The addition amount of the sensitizing dye in the present invention can be a desired amount in accordance with the sensitivity and the performance of fogging, but is preferably 10 ^{-6 to} 1 mol, more preferably 1 to 1 mol per mol of silver halide in the photosensitive layer.
0 ^-4 to 10 ^-1 mol.

According to the present invention, in order to improve the spectral sensitization efficiency,
Supersensitizers can be used. Strong color used in the present invention
As sensitizers, European Patent Publication No. 587,338
No. 3,877,943, U.S. Pat.
No. 873,184;
Aromatic or aliphatic mercapto compounds, heteroaromatic di
Sulfide compounds, stilbene, hydrazine, triazine
And the like. Especially preferred
Super sensitizers are disclosed in JP-A-5-341432.
Heteroaromatic mercapto compounds, heteroaromatic di
A sulfide compound, disclosed in JP-A-4-182,639
A compound represented by the general formula (I) or (II);
No. 10-111543, which is represented by the general formula (I).
Tilbene compound, one of JP-A-11-109947
It is a compound represented by the general formula (I). Specifically,
Compounds of M-1 to M-24 in JP-A-5-341432
, D-1) to d-1 of JP-A-4-182639
Compound 4), SS described in JP-A-10-111543
-01 to SS-07, JP-A-11-10954
No. 7, 31, 32, 37, 38, 41-45, 51
~ 53 compounds. Addition amount of these supersensitizers
Is 10 per mol of silver halide in the emulsion layer. ^-Four~ 1
mol is preferable, and per mol of silver halide
The range of 0.001 to 0.3 mol is more preferable.

The photothermographic material of the present invention preferably contains a reducing agent for an organic silver salt. The reducing agent for the organic silver salt is any substance that reduces silver ions to metallic silver, preferably an organic substance. Conventional photographic developers such as phenidone, hydroquinone and catechol are useful, but hindered phenol reducing agents are preferred. The reducing agent is used in an amount of 5 to 50 mol based on 1 mol of silver on the surface having the image forming layer.
%, More preferably 10 to 40 mol%. The layer to which the reducing agent is added may be any layer on the image forming layer side with respect to the support. When added to a layer other than the image forming layer 10-5 of silver 1mol is
It is preferable to use as much as 0 mol%. Further, the reducing agent may be a so-called precursor which is derivatized so as to function effectively only during development.

In a photothermographic material utilizing an organic silver salt, a wide range of reducing agents can be used. For example,
JP-A-46-6074, JP-A-47-1238, JP-A-47-33621, JP-A-49-46427, JP-A-49-115540, and JP-A-50-1433.
No. 4, No. 50-36110, No. 50-147
Nos. 711 and 51-32632 and 51-1
JP-A Nos. 023721, 51-32324, and 5
1-51933, 52-84727, 55-108654, 56-146133, 57-82828, 57-82829, JP-A-6-3793, U.S.A. Patent No. 3,67
9,426, 3,751,252, 3,751,255, 3,763
Nos. 1,270, 3,782,949, 3,839,048, 3,92
No. 8,686, 5,464,738, German Patent 2,321,328, European Patent Publication 692,732 and the like are used. be able to. For example, amide oximes such as phenylamidooxime, 2-thienylamidooxime and p-phenoxyphenylamidooxime; azines such as 4-hydroxy-3,5-dimethoxybenzaldehydeazine; 2,2'-bis (hydroxymethyl) propionyl A combination of an aliphatic carboxylic acid aryl hydrazide such as a combination of β-phenylhydrazine and ascorbic acid and ascorbic acid; a combination of polyhydroxybenzene and hydroxylamine, reductone and / or hydrazine (for example, hydroquinone and bis (ethoxy) Ethyl) hydroxylamine, piperidinohexose reductone or a combination of formyl-4-methylphenylhydrazine, etc.); phenylhydroxamic acid, p-hydroxyphenylhydroxam And hydroxamic acids, such as β- ants Nin hydroxamic acid;
A combination of azine and sulfonamidophenol (for example, phenothiazine and 2,6-dichloro-4-benzenesulfonamidophenol); α such as ethyl-α-cyano-2-methylphenylacetate and ethyl-α-cyanophenylacetate A cyanophenylacetic acid derivative; 2,2′-dihydroxy-1,1′-binaphthyl,
6,6′-dibromo-2,2′-dihydroxy-1,
Bis-β-naphthol as exemplified by 1′-binaphthyl and bis (2-hydroxy-1-naphthyl) methane; bis-β-naphthol and 1,3-dihydroxybenzene derivatives (eg, 2,4-dihydroxybenzophenone Or 5-pyrazolone such as 3-methyl-1-phenyl-5-pyrazolone; dimethylaminohexose reductone, anhydrodihydroaminohexose reductone and anhydrodihydro Reductones as exemplified by piperidone hexose reductone; sulfonamide phenol reducing agents such as 2,6-dichloro-4-benzenesulfonamidophenol and p-benzenesulfonamidophenol; 2-phenylindane-1,
Chromanes such as 2,2-dimethyl-7-tert-butyl-6-hydroxychroman; 2,6
1,4-dihydropyridines such as -dimethoxy-3,5-dicarbethoxy-1,4-dihydropyridine; bisphenols (for example, bis (2-hydroxy-3-te)
rt-butyl-5-methylphenyl) methane, 2,2-
Bis (4-hydroxy-3-methylphenyl) propane, 4,4-ethylidene-bis (2-tert-butyl-6-methylphenol), 1,1, -bis (2-hydroxy-3,5-dimethylphenyl) ) -3,5,5-trimethylhexane and 2,2-bis (3,5-dimethyl-4-hydroxyphenyl) propane, etc.); ascorbic acid derivatives (eg, 1-ascorbyl palmitate, ascorbyl stearate, etc.); And aldehydes and ketones such as benzyl and biacetyl; 3
-Pyrazolidone and certain indane-1,3-diones; chromanols (such as tocopherol).
Particularly preferred reducing agents are bisphenol, chromanol.

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

When an additive known as a "toning agent" for improving an image is included, the optical density may increase.
The toning agent may also be advantageous in forming a black silver image. The color tone agent is preferably contained in the layer on the image forming layer side of the support in an amount of 0.1 to 50% mol per 1 mol of silver, more preferably 0.5 to 20% mol. Further, the toning agent may be a so-called precursor which is derivatized so as to function effectively only during development. In a photothermographic material using an organic silver salt, a wide range of color toning agents can be used. For example, JP-A-46-6077 and JP-A-47-10282
JP-A-49-5019, JP-A-49-5020, JP-A-49-91215, and 49-91215
JP, 50-5024, and 50-32927
JP, 50-67132, and 50-6764
No. 1, No. 50-114217, No. 51-32
No. 23, No. 51-27923, No. 52-14
No. 788, No. 52-99813, No. 53-1
No. 020, 53-76020, 54-1
Nos. 56524, 54-156525, 6
1-1183624, JP-A-4-56848, JP-B-49-10727, and 54-2033.
3, U.S. Pat. Nos. 3,080,254, 3,446,648, and 3,782,94.
No. 1, No. 4,123,282, No. 4,510,236, British Patent No. 1,380,
No. 795, Belgian Patent No. 841,910 and the like can be used. Specific examples of the toning agent include phthalimide and N-hydroxyphthalimide; succinimide, pyrazolin-5-one, and quinazolinone, 3-phenyl-2-pyrazolin-5-one, 1-phenylurazole, quinazoline, and 2,4- Cyclic imides such as thiazolidinedione; naphthalimides (eg, N-hydroxy-1,8
-Naphthalimide); cobalt complex (e.g., cobalt hexamine trifluoroacetate); 3-mercapto-1,2,4-triazole, 2,4-dimercaptopyrimidine, 3-mercapto-4,5-diphenyl-1,
2,4-triazole and 2,5-dimercapto-
Mercaptans exemplified by 1,3,4-thiadiazole; N- (aminomethyl) aryldicarboximides (eg, (N, N-dimethylaminomethyl) phthalimide and N, N- (dimethylaminomethyl) -naphthalene- 2,3-dicarboximide); and blocked pyrazoles, isothiuronium derivatives, and certain photobleaching agents (eg, N, N'-hexamethylenebis (1-carbamoyl-3,5-dimethylpyrazole), 1,8 -(3,6-diazaoctane) bis (isothiuronium trifluoroacetate) and 2- (tribromomethylsulfonyl) -benzothiazole; and 3-ethyl-5-[(3-ethyl-2-benzothiazolinylidene) ) -1-Methylethylidene] -2-thio-
2,4-oxazolidinedione; phthalazinone, phthalazinone derivative or metal salt, or 4- (1-naphthyl) phthalazinone, 6-chlorophthalazinone, 5,7-
Dimethoxyphthalazinone and 2,3-dihydro-1,
Derivatives such as 4-phthalazinedione; combinations of phthalazinone with phthalic acid derivatives (for example, phthalic acid, 4-methylphthalic acid, 4-nitrophthalic acid and tetrachlorophthalic anhydride); phthalazine, phthalazine derivatives (for example, 4- (1-naphthyl) phthalazine, 6-chlorophthalazine, 5,7-dimethoxyphthalazine, 6-
Derivatives such as isobutylphthalazine, 6-tert-butylphthalazine, 5,7-dimethylphthalazine, and 2,3-dihydrophthalazine) or metal salts; phthalazine and its derivatives and phthalic acid derivatives (for example, phthalic acid, Combinations with 4-methylphthalic acid, 4-nitrophthalic acid and tetrachlorophthalic anhydride); quinazolinedione, benzoxazine or naphthoxazine derivatives; halide ions for silver halide formation in situ, not only as color tone regulators Complexes which also function as sources of, for example, ammonium hexachlororhodate (III), rhodium bromide, rhodium nitrate and potassium hexachlororhodate (III); inorganic peroxides and persulfates, such as ammonium disulfide And hydrogen peroxide; 1, - benzoxazine-2,4
Dione, 8-methyl-1,3-benzoxazine-2,
Benzoxazine-2,4- such as 4-dione and 6-nitro-1,3-benzoxazine-2,4-dione
Diones; pyrimidines and asymmetric-triazines (eg,
2,4-dihydroxypyrimidine, 2-hydroxy-4
-Aminopyrimidine, etc.), azauracil, and tetraazapentalene derivatives (eg, 3,6-dimercapto-1,4-diphenyl-1H, 4H-2,3a, 5,5)
6a-tetraazapentalene and 1,4-di (o-
(Chlorophenyl) -3,6-dimercapto-1H, 4H
-2,3a, 5,6a-tetraazapentalene) and the like.

In the present invention, as a color tone agent, JP-A-2000-
A phthalazine derivative represented by the general formula (F) described in JP-A-35631 is preferably used. Specifically, A-1 to A-10 described in the publication are preferably used.

The color-toning agent may be added by any method such as a solution, a powder and a dispersion of solid fine particles. The dispersion of the solid fine particles is carried out by a known fine means (for example, ball mill, vibrating ball mill, sand mill, colloid mill, jet mill, roller mill, etc.). When dispersing the solid fine particles, a dispersing aid may be used.

The surface pH of the photothermographic material of the present invention before heat development is preferably 6.0 or less, more preferably 5.5 or less. The lower limit is not particularly limited, but is about 3. For adjusting the film surface pH, it is preferable to use an organic acid such as a phthalic acid derivative, a nonvolatile acid such as sulfuric acid, or a volatile base such as ammonia from the viewpoint of reducing the film surface pH. In particular, ammonia is preferable in achieving a low film surface pH since ammonia is easily volatilized and can be removed before the application step and the heat development. Note that the film surface p
The method for measuring H is described in paragraph No. 0123 of JP-A-2000-284399.

In the photothermographic material of the present invention, the silver halide emulsion and / or the organic silver salt may contain an antifoggant,
Stabilizers and stabilizer precursors can further protect against the formation of additional fog and stabilize against reduced sensitivity during storage in inventory. Suitable antifoggants, stabilizers and stabilizer precursors that can be used alone or in combination are described in US Pat. No. 2,131,03.
No. 8, No. 2,694,716, azaindenes described in U.S. Pat. Nos. 2,886,437 and 2,444,605, U.S. Pat. No. 2,728,663, mercury salts described in U.S. Pat. No. 3,287,135, urazole described in U.S. Pat. No. 3,287,135, U.S. Pat. No. 3,235,652.
Patent No. 62, UK Patent No. 62
Oxime, nitrone, nitroindazole described in US Pat. No. 3,448, polyvalent metal salt described in US Pat. No. 2,839,405, US Pat. No. 3,220,839.
No. 2,566,263 and U.S. Pat. No. 2,597,9.
15, palladium, platinum and gold salts; U.S. Pat. Nos. 4,108,665 and 4,4;
No. 4,128,557 and U.S. Pat. Nos. 4,137,079 and 4,138,365.
And the phosphorus compounds described in U.S. Pat. No. 4,411,985.

The photothermographic material of the present invention may contain benzoic acids for the purpose of increasing the sensitivity and preventing fog. The benzoic acid used in the present invention may be any benzoic acid derivative, but a preferred example is described in US Pat.
No. 939, No. 4,152,160, JP-A-9-329863, JP-A-9-329864, and JP-A-9-281637. The benzoic acid may be added to any layer of the photothermographic material, but is preferably added to the layer on the image forming layer side with respect to the support, more preferably to the organic silver salt-containing layer. The addition of benzoic acids may be performed at any step in the preparation of the coating solution, and when the benzoic acid is added to the organic silver salt-containing layer, any step from the preparation of the organic silver salt to the preparation of the coating solution may be performed, but the coating is performed after the preparation of the organic silver salt. Immediately before is preferred.
The benzoic acid may be added by any method such as powder, solution, and fine particle dispersion. Further, it may be added as a solution mixed with other additives such as a sensitizing dye, a reducing agent, and a color tone agent. The benzoic acid may be added in any amount, but may be 1 × 10 ⁻⁶ mol to 2 mol per mol of silver.
1 is preferable, and 1 × 10 ⁻³ mol to 0.5 mol is more preferable.

Although not essential for practicing the present invention,
Mercury (II) salt added to image forming layer as antifoggant
May be advantageous. Preferred for this purpose
Mercury (II) salts are mercury acetate and mercury bromide. Book
The added amount of mercury used in the present invention is as follows.
preferably 1 × 10 per mol^-9mol ~ 1 × 10 ^-3
mol, more preferably 1 × 10^-8mol ~ 1 × 10
^-Fourmol range.

The antifoggant particularly preferably used in the present invention is an organic halide.
No. 119624, No. 50-120328, No. 51-121332, No. 54-58022, No. 56-70543, No. 56-99335, No. 59-90842, No. 61-12964.
No. 2, JP-A-62-129845, and JP-A-6-2
JP 08191, JP 7-5621, JP 7-27
No. 81, 8-15809, U.S. Pat.
Compounds disclosed in 340,712, 5,369,000, and 5,464,737 can be mentioned. JP-A-2000-2843
The hydrophilic organic halide represented by the formula (P) described in JP-A-99-99 is preferably used as an antifoggant. Specifically, (P-1) to (P-118) described in the publication
Is preferably used. The amount of organic halide added is
Mol amount per mol Ag (mol / mol Ag)
And preferably 1 × 10 ^{−5 to 2} mol / molA
g, more preferably 5 × 10 ^{−5 to 1} mol / molA
g, more preferably 1 × 10 ^{-4 to} 5 × 10 ^-1 mol / g.
molAg. These may be used alone or in combination of two or more.

Further, Japanese Patent Application Laid-Open No. 2000-284399
The salicylic acid derivative represented by the formula (Z) described in
It is preferably used as an inhibitor. Specifically, the gazette
(A-1) to (A-60) described in are preferably used.
You. The amount of the salicylic acid derivative represented by the formula (Z) is:
Mol amount per mol Ag (mol / mol Ag)
, Preferably 1 × 10^-Five~ 5 × 10^-1mol /
molAg, more preferably 5 × 10^-Five~ 1 × 10^-1m
ol / mol Ag, more preferably 1 × 10 ^-Four~ 5x
10^-2mol / mol Ag. These are only one kind
They may be used or two or more of them may be used in combination.

As the antifoggant preferably used in the present invention, formalin scavenger is effective. For example, the compound represented by the formula (S) described in JP-A-2000-221634 and its exemplified compound (S-
1) to (S-24).

The antifoggant used in the present invention may be water or a suitable organic solvent such as alcohols (methanol, methanol, etc.).
It can be used by dissolving in ethanol, propanol, fluorinated alcohol), ketones (acetone, methyl ethyl ketone), dimethylformamide, dimethylsulfoxide, methylcellosolve and the like. In addition, dibutyl phthalate,
Oils such as tricresyl phosphate, glyceryl triacetate or diethyl phthalate, dissolved using an auxiliary solvent such as ethyl acetate or cyclohexanone,
An emulsified dispersion can be prepared and used mechanically. Alternatively, the powder can be dispersed in water by a ball mill, a colloid mill, a sand grinder mill, a Menton-Gaulin, a microfluidizer or an ultrasonic wave by a method known as a solid dispersion method.

The antifoggant used in the present invention may be added to the layer on the image forming layer side with respect to the support, that is, the image forming layer or any other layer on this layer side. It is preferable to add it to an adjacent layer. The image forming layer is a layer containing a reducible silver salt (organic silver salt), and is preferably an image forming layer further containing a photosensitive silver halide.

The photothermographic material of the present invention contains a mercapto compound, a disulfide compound, or a thione compound for the purpose of controlling or suppressing the development by improving the development, or improving the preservability before and after the development. Can be. When a mercapto compound is used in the present invention, any structure may be used, but Ar-SM, Ar
Those represented by -SS-Ar are preferred. In the formula, M is a hydrogen atom or an alkali metal atom, and Ar is an aromatic ring or a condensed aromatic ring having one or more nitrogen, sulfur, oxygen, selenium or tellurium atoms. Preferably, the heteroaromatic ring is benzimidazole, naphthimidazole, benzothiazole, naphthothiazole, benzoxazole, naphthoxazole, benzoselenazole, benzotellurazole, imidazole, oxazole, pyrazole, triazole, thiadiazole, tetrazole, triazine, pyrimidine, pyridazine , Pyrazine, pyridine, purine, quinoline or quinazolinone. The heteroaromatic ring can be, for example, halogen (eg, Br and Cl), hydroxy, amino, carboxy, alkyl (eg, having one or more carbon atoms, preferably 1-4 carbon atoms), alkoxy ( For example, it may have a substituent selected from the group consisting of one or more carbon atoms, preferably those having 1 to 4 carbon atoms, and aryl (which may have a substituent). Good. Examples of the mercapto-substituted heteroaromatic compound include 2-mercaptobenzimidazole, 2-mercaptobenzoxazole, 2-mercaptobenzothiazole, 2-mercapto-5-methylbenzimidazole,
6-ethoxy-2-mercaptobenzothiazole, 2,
2'-dithiobis- (benzothiazole), 3-mercapto-1,2,4-triazole, 4,5-diphenyl-2-imidazolethiol, 2-mercaptoimidazole, 1-ethyl-2-mercaptobenzimidazole, 2- Mercaptoquinoline, 8-mercaptopurine,
2-mercapto-4 (3H) -quinazolinone, 7-trifluoromethyl-4-quinolinethiol, 2,3,5
6-tetrachloro-4-pyridinethiol, 4-amino-6-hydroxy-2-mercaptopyrimidine monohydrate, 2-amino-5-mercapto-1,3,4-thiadiazole, 3-amino-5-mercapto- 1,2,
4-triazole, 4-hydrokilocy-2-mercaptopyrimidine, 2-mercaptopyrimidine, 4,6-diamino-2-mercaptopyrimidine, 2-mercapto-4-
Methyl pyrimidine hydrochloride, 3-mercapto-5
-Phenyl-1,2,4-triazole, 1-phenyl-5-mercaptotetrazole, sodium 3- (5-mercaptotetrazole) -benzenesulfonate, N-
Methyl-N '-{3- (5-mercaptotetrazolyl)
Examples include phenyl diurea and 2-mercapto-4-phenyloxazole, but the present invention is not limited thereto. The amount of the mercapto compound added is 0.0001 to 1.0 m per mol of silver in the image forming layer.
ol is preferable, and more preferably 1 mol of silver.
The amount is 0.001 to 0.3 mol per 1.

The photothermographic material of the present invention is provided on a support.
It is preferable to have an image forming layer containing an organic silver salt, a reducing agent and a photosensitive silver halide, and to provide at least one protective layer on the image forming layer. Further, the photothermographic material of the present invention preferably has at least one back layer on the side (back surface) opposite to the image forming layer with respect to the support, and the image forming layer, the protective layer, and the binder Is used as a polymer latex. By using a polymer latex for these layers, aqueous coating using a solvent (dispersion medium) containing water as a main component becomes possible, which is advantageous in terms of environment and cost, and causes wrinkles during thermal development. A heat-developable photosensitive material can be obtained. Further, by using a support which has been subjected to a predetermined heat treatment, a photothermographic material having a small dimensional change before and after thermal development can be obtained.

In the present invention, a slip agent can be used.
As used herein, the term “slip agent” refers to a compound that reduces the coefficient of friction on the surface of an object when present on the surface of the object, as compared to the case where it is not present. The type is not particularly limited.

The slip agent used in the present invention is disclosed in
Paragraph Nos. 0061 to 0064 of 1-84573,
Paragraph No. 0049 of Japanese Patent Application No. 11-106881
To 0062. Specific examples of preferred lubricants include Cellolsol 524 (main component carnauba wax), Polylon A, 393, H-48.
1 (main component polyethylene wax), high micron G-
110 (main component ethylene bisstearic acid amide),
Himicron G-270 (main component stearic acid amide) (all from Chukyo Yushi _{(Co.)), W-1 C 16} H 33 -O-SO 3 Na W-2 C 18 H 37 -O-SO 3 Na etc. Is mentioned. The amount of the slip agent used is 0.1 to 50% by mass of the binder amount of the additive layer, preferably 0.5 to 50% by mass.
30% by mass.

In the present invention, Japanese Patent Application Laid-Open No. 2000-1719
No. 35, the pre-heating unit is conveyed by a facing roller as described in Japanese Patent Application No. 11-106881, and the heat development processing unit drives the roller having the image forming layer on the side having the image forming layer.
In the case of using a heat development processing apparatus that conveys the opposite back surface by sliding it to a smooth surface, the outermost surface layer on the side having the image forming layer of the photothermographic material at the development processing temperature and the outermost surface layer on the back surface Is 1.5 or more, and there is no particular upper limit, but it is about 30. Also, μb
Is 1.0 or less, preferably 0.05 to 0.8. This value is obtained by the following equation. Ratio of friction coefficient = dynamic friction coefficient (μe) between roller member of heat developing machine and surface having image forming layer / dynamic friction coefficient (μb) of smooth surface member and back surface of heat developing machine (heat) The lubricating property of the outermost surface layer on the surface having the heat development processing machine member and the image forming layer and / or the opposite surface thereof can be adjusted by including a slipping agent in the outermost surface layer and changing the amount of addition. it can.

On both sides of the support, JP-A-64-2054
4, JP-A-1-180537, JP-A-1-18037
No. 209443, JP-A-1-285939,
JP-A-1-296243, JP-A-2-24649
JP, JP-A-2-24648, JP-A-2-18-18
4844, JP-A-3-109545, JP-A-3-137637, JP-A-3-141346, JP-A-3-141347, JP-A-4-96
No. 055, U.S. Pat. No. 4,645,731, JP-A-4-68344, and Japanese Patent No. 2,557,
No. 641, page 2, right column, line 20 to page 3, right column, line 30;
Paragraph No. 0020 of JP-A-2000-39684
It is preferable to provide an undercoat layer containing a vinylidene chloride copolymer containing 70% by mass or more of a vinylidene chloride monomer repeating unit described in paragraphs 0063 to 0080 of Japanese Patent Application No. 2000-47083.

When the amount of the vinylidene chloride monomer is less than 70% by mass, sufficient moisture-proof properties cannot be obtained, and the dimensional change over time after thermal development becomes large. Further, the vinylidene chloride copolymer preferably contains a repeating unit of a carboxyl group-containing vinyl monomer as another constituent repeating unit of the vinylidene chloride monomer. It is only vinyl chloride monomer that contains such a repeating unit.
The polymer (polymer) crystallizes, making it difficult to form a uniform film when applying a moisture-proof layer, and a carboxyl group-containing vinyl monomer is indispensable for stabilizing the polymer (polymer). Because there is. The vinylidene chloride copolymer used in the present invention has a weight average molecular weight of 45.0.
00 or less, more preferably 10,000 to 45,000. When the molecular weight is increased, the adhesiveness between the vinylidene chloride copolymer layer and a support layer such as polyester tends to deteriorate.

The content of the vinylidene chloride copolymer used in the present invention is 0.3 μm or more as a total film thickness per one side of the undercoat layer containing the vinylidene chloride copolymer.
Preferably it is in the range of 0.3 μm to 4 μm.

The vinylidene chloride copolymer layer as the undercoat layer is preferably provided as the first undercoat layer directly provided on the support, and is usually provided one layer on each side. May be provided in two or more layers.
When a multi-layer structure of two or more layers is used, the total amount of the vinylidene chloride copolymer may fall within the range of the present invention.
Such a layer may contain a crosslinking agent, a matting agent, and the like in addition to the vinylidene chloride copolymer.

The support may be coated with an undercoat layer using SBR, polyester, gelatin or the like as a binder, if necessary, in addition to the vinylidene chloride copolymer layer. These undercoat layers may have a multilayer structure or may be provided on one side or both sides of the support. The thickness of the undercoat layer (per layer) is generally 0.01 to 5 μm, more preferably 0.1 to 5 μm.
05 to 1 μm.

Various supports can be used for the photothermographic material of the present invention. Typical supports include polyesters such as polyethylene terephthalate and polyethylene naphthalate, cellulose nitrate, cellulose esters, polyvinyl acetal, syndiotactic polystyrene, polycarbonate, and paper supports coated on both sides with polyethylene. Of these, biaxially stretched polyester, particularly polyethylene terephthalate (PET), is preferred in terms of strength, dimensional stability, chemical resistance and the like. The thickness of the support is preferably 90 to 180 μm as a base thickness excluding the undercoat layer.

As the support used in the photothermographic material of the present invention, JP-A-10-48772 and JP-A-10-87772
10676, JP-A-10-10677, JP-A-11-65025, JP-A-11-13864
No. 8, polyester which has been subjected to a heat treatment in a temperature range of 130 to 185 ° C. in order to alleviate internal strain remaining in the film at the time of biaxial stretching and eliminate heat shrinkage strain generated during thermal development processing. Particularly, polyethylene terephthalate is preferably used.

The support 12 after such heat treatment was used.
The dimensional change rate by heating at 0 ° C. for 30 seconds is −0.03% to + 0.01% in the vertical direction (MD), and 0 in the horizontal direction (TD).
Preferably, it is 0.04%.

The photothermographic material of the present invention has been disclosed in JP-A-11-84573, paragraphs [0040] to [0051], for the purpose of reducing dust adhesion, preventing the occurrence of static marks, and preventing defective transport in the automatic transport step. Can be prevented by using the conductive metal oxide and / or the fluorine-based surfactant described in (1). As the conductive metal oxide, US Pat. No. 5,575,957, JP-A-11-22
Needle-shaped conductive tin oxide doped with antimony described in paragraphs 0012 to 0020 of JP-A-3901 and fibrous tin oxide doped with antimony described in JP-A-4-29134 are preferably used.

The surface resistivity (surface resistivity) of the metal oxide-containing layer is 10 ¹² Ω or less, preferably 10 ¹¹ Ω or less in an atmosphere at 25 ° C. and a relative humidity of 20%. Thereby, good antistatic properties can be obtained. Although the lower limit of the surface resistivity at this time is not particularly limited, it is usually about 10 ⁷ Ω.

The Beck smoothness of at least one of the surface having the image forming layer of the photothermographic material of the invention and the outermost layer surface opposite to the surface, and preferably both, is 5,000 seconds or less, more preferably 10 seconds or less. 2000 seconds. The Beck smoothness in the present invention is determined by the Japanese Industrial Standards (JIS).
It can be easily obtained by P8119 “Smoothness test method of paper and paperboard with Beck tester” and TAPPI standard method T479. The Beck smoothness of the outermost layer on the surface having the image forming layer of the photothermographic material and the outermost layer on the opposite side are described in paragraph No. 00 of JP-A-11-84573.
As described in 52 to 0059, it can be controlled by appropriately changing the particle size and the amount of the matting agent contained in the layers on both surfaces.

In the present invention, a water-soluble polymer is preferably used as a thickener for imparting coatability, and may be a natural or synthetic polymer, and the type thereof is not particularly limited. Specifically, as natural products, starches (corn starch,
Starch, etc.), seaweed (agar, sodium alginate, etc.), vegetable glue (gum arabic, etc.), animal protein (glue, casein, gelatin, egg white, etc.), fermented glue (pullulane, dextrin, etc.), etc. Semi-synthetic polymers such as starchy materials (soluble starch, carboxyl starch, dextran, etc.) and celluloses (viscose, methylcellulose, ethylcellulose,
Carboxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, etc.), and synthetic polymers (polyvinyl alcohol, polyacrylamide,
Polyvinyl pyrrolidone, polyethylene glycol, polypropylene glycol, polyvinyl ether, polyethylene imine, polystyrene sulfonic acid or its copolymer, polyvinyl sulfinic acid or its copolymer, polyacrylic acid or its copolymer, acrylic acid or its copolymer, etc. , Maleic acid copolymer, maleic acid monoester copolymer, acryloylmethylpropanesulfonic acid or a copolymer thereof).

Among these, the water-soluble polymers preferably used include sodium alginate, gelatin, dextran, dextrin, methylcellulose, carboxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, polyvinyl alcohol, polyacrylamide, polyvinylpyrrolidone, polyethylene glycol, polypropylene glycol, Polystyrene sulfonic acid or its copolymer, polyacrylic acid or its copolymer, maleic acid monoester copolymer, acryloylmethylpropane sulfonic acid or its copolymer, and the like are particularly preferably used as a thickener.

Among these, particularly preferred thickeners include
Examples include gelatin, dextran, methylcellulose, carboxymethylcellulose, hydroxyethylcellulose, polyvinyl alcohol, polyacrylamide, polyvinylpyrrolidone, polystyrenesulfonic acid or a copolymer thereof, polyacrylic acid or a copolymer thereof, and a maleic acid monoester copolymer. These compounds are
It is described in detail in "Applications and Markets of New Water-Soluble Polymers" (published by CMC Corporation, edited by Shinji Nagatomo, issued on November 4, 1988).

The amount of the water-soluble polymer used as a thickener is not particularly limited as long as the viscosity increases when added to a coating solution. Generally, the concentration in the liquid is 0.01 to 30% by mass, more preferably 0.05 to 20% by mass, and particularly preferably 0.1 to 10% by mass. The viscosity obtained by these methods is 1 to 200 mPa as an increase from the initial viscosity.
S is preferable, and more preferably 5 to 100 mPa · s
It is. The viscosity is a value measured at 25 ° C. with a B-type rotational viscometer. When adding to a coating solution or the like, it is generally desirable to add the thickener in a solution as dilute as possible. In addition, it is preferable to perform sufficient stirring during the addition.

The surfactant used in the present invention will be described below. Surfactants used in the present invention are classified into dispersants, coating agents, wetting agents, antistatic agents, photographic control agents, and the like according to the purpose of use. By doing so, those goals can be achieved. The surfactant used in the present invention may be either nonionic or ionic (anion, cation, betaine). Further, a fluorine-based surfactant is also preferably used.

Preferred nonionic surfactants include:
Polyoxyethylene, polyoxypropylene, polyoxybutylene, polyglycidyl and a surfactant having a nonionic hydrophilic group of sorbitan can be mentioned. Specifically, polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether Polyoxyethylene-polyoxypropylene glycol, polyhydric alcohol fatty acid partial ester, polyoxyethylene polyhydric alcohol fatty acid partial ester, polyoxyethylene fatty acid ester, polyglycerin fatty acid ester, fatty acid diethanolamide, and triethanolamine fatty acid partial ester. be able to.

Examples of the anionic surfactant include a carboxylate, a sulfate, a sulfonate and a phosphate ester. Representative examples thereof include a fatty acid salt, an alkylbenzene sulfonate and an alkylnaphthalenesulfonic acid. Salt, alkyl sulfonate, α-olefin sulfonate, dialkyl sulfosuccinate, α-sulfonated fatty acid salt, N-methyl-N-oleyltaurine, petroleum sulfonate, alkyl sulfate, sulfated oil, polyoxy Examples include ethylene alkyl ether sulfate, polyoxyethylene alkyl phenyl ether sulfate, polyoxyethylene styrenated phenyl ether sulfate, alkyl phosphate, polyoxyethylene alkyl ether phosphate, and naphthalene sulfonate formaldehyde condensate. Can be.

As the cationic surfactant, amine salts,
Examples thereof include quaternary ammonium salts, pyridium salts, and the like. Primary to tertiary fatty amine salts, quaternary ammonium salts (tetraalkylammonium salts, trialkylbenzylammonium salts, alkylpyridium salts, alkylimidazolium salts, and the like) ).

Examples of the betaine-based surfactant include carboxybetaine and sulfobetaine.
-Trialkyl-N-carboxymethylammonium betaine, N-trialkyl-N-sulfoalkylammonium betaine and the like.

These surfactants are described in “Application of Surfactants” (written by Koshobo and Takao Karimei, published on September 1, 1980).
It is described in. In the present invention, a preferred surfactant is not particularly limited in its use amount, and any surfactant may be used as long as desired surfactant properties can be obtained. The amount of the fluorine-containing surfactant applied is 0.01 mg / m ^{2 or} more.
250 mg is preferred.

Specific examples of the surfactant are described below, but the surfactant which can be used in the present invention is not limited to these specific examples (here, -C ₆ H ₄ -is a phenylene group). Represents). _{WA-1: C 16 H 33} (OCH 2 CH 2) 10 OH WA-2: C 9 H 19 -C 6 H 4 - (OCH 2 CH 2) 12 OH WA-3: sodium dodecylbenzene sulfonate WA-4 : Sodium tri (isopropyl) naphthalenesulfonate WA-5: sodium tri (isobutyl) naphthalenesulfonate WA-6: sodium dodecyl sulfate WA-7: di- (2-ethylhexyl) α-sulfosuccinate sodium salt WA-8: _{C 8 H 17 -C 6 H 4} - (CH 2 CH 2 O) 3 (CH 2) 2 SO 3 K WA-10: cetyltrimethylammonium chloride _{WA-11: C 11 H 23} CONHCH 2 CH 2 N (+) (CH ₃ ) ₂ -CH ₂ COO ⁽⁻⁾ WA-12: C ₈ F ₁₇ SO ₂ N (C ₃ H ₇ ) (CH ₂ CH ₂ O) ₁₆ H WA-13: C ₈ F ₁₇ SO ₂ N ( _{C 3 H 7) CH 2 COOK} WA-14: C 8 F 17 SO 3 K WA-15: C 8 F 17 SO 2 N (C 3 H 7) (CH 2 CH 2 O) 4 (CH 2) 4 SO ₃ Na WA-16: C ₈ F ₁₇ SO ₂ N (C ₃ H ₇ ) (CH ₂ ) ₃ OCH ₂ CH ₂ N ⁽⁺⁾ (CH ₃ ) ₃ -CH ₃ .C ₆ H ₄ -SO ₃ ^(-) WA-17: C ₈ F ₁₇ SO ₂ N ( C ₃ H ₇ ) CH ₂ CH ₂ CH ₂ N ⁽⁺⁾ (CH ₃ ) ₂ -CH ₂ COO ^(-)

In a preferred embodiment of the present invention, an intermediate layer may be provided, if necessary, in addition to the image forming layer and the protective layer. For the purpose of improving productivity and the like, it is preferable that these plural layers are simultaneously coated in an aqueous system. The coating method includes extrusion coating, slide bead coating, curtain coating, and the like.
The slide bead coating method shown in FIG.

In the case of a silver halide photographic material using gelatin as a main binder, the material is rapidly cooled in a first drying zone provided downstream of a coating die, and as a result, gelatinization of gelatin occurs, and the coating film is cooled. Is solidified. The coating film that has been cooled and solidified and has stopped flowing is guided to the subsequent second drying zone, where the solvent in the coating solution is volatilized and formed into a film in the subsequent drying zone. As a drying method after the second drying zone, an air loop method in which a jet is blown from a U-shaped duct to a roller-supported support, or a support in which the support is wound around a cylindrical duct in a helical shape, is conveyed and dried. A fire method (air floating method) and the like can be mentioned.

When a layer is formed using a coating liquid in which the main component of the binder is a polymer latex, the flow of the coating liquid cannot be stopped by rapid cooling, so that the preliminary drying is insufficient only in the first drying zone. In some cases.
In this case, in a drying method such as used in a silver halide photographic light-sensitive material, flow unevenness and drying unevenness occur, and a serious defect is easily generated on the coated surface.

[0126] A preferable drying method in the present invention is, regardless of the first drying zone or the second drying zone described in JP-A-2000-2964, at least until the constant-rate drying is completed. This is a method of drying in a drying zone. The transfer of the support from the time immediately after the coating until the support is guided to the horizontal drying zone may or may not be horizontal, and the rising angle of the coating machine with respect to the horizontal direction may be between 0 and 70 °. In addition, the horizontal drying zone in the present invention only needs to be conveyed within ± 15 ° up and down with respect to the horizontal direction of the coating machine, and does not mean horizontal conveyance.

The constant-rate drying in the present invention means a drying process in which a liquid film temperature is constant and all the heat flowing in is used for evaporating the solvent. Derate-rate drying means that at the end of drying, the drying speed decreases due to various factors (such as the rate of moisture diffusion inside the material and the evaporation surface recedes), and the applied heat is also used to increase the liquid film temperature. Drying process. The critical water content at which the transition from the constant rate process to the rate reduction process is 200-3
00%. When the constant-rate drying is completed, the drying proceeds sufficiently until the flow stops, and thus a drying method such as a silver halide photographic light-sensitive material can be employed. It is preferred to dry in the horizontal drying zone to the drying point.

The drying conditions when forming the image forming layer and / or the protective layer are such that the liquid film surface temperature during constant rate drying is 3 to less than the minimum film forming temperature of polymer latex (MTF; usually, glass transition temperature Tg of polymer). (5 ° C. higher) or more. Normally 25 ° C to 40 ° C due to limitations of manufacturing equipment
Often. Further, the dry-bulb temperature during the rate-decreasing drying is preferably a temperature lower than the Tg of the support (usually 80 ° C. or lower in the case of PET). The liquid film surface temperature in this specification refers to the solvent liquid film surface temperature of the coating liquid film applied to the support, and the dry bulb temperature refers to the temperature of the drying air in the drying zone.

When drying is performed under the condition that the liquid film surface temperature during constant rate drying is low, the drying tends to be insufficient. For this reason, particularly, the film forming property of the protective layer is significantly reduced, and cracks are easily generated on the film surface. In addition, the film strength is weakened, and serious problems such as susceptibility to damage during transport in an exposure machine or a heat developing machine are likely to occur.

On the other hand, when dried under the condition that the liquid film surface temperature becomes high, the protective layer mainly composed of polymer latex quickly forms a film, while the lower layer such as the image forming layer has low fluidity. Since it is not stopped, irregularities are likely to be generated on the surface. Further, when excessive heat higher than Tg is applied to the support (base), the dimensional stability and the curl resistance of the photosensitive material tend to deteriorate.

[0131] The same applies to the sequential coating in which the lower layer is coated and dried and then the upper layer is coated. Particularly, the coating for performing the simultaneous multi-layer coating in which the upper layer is coated before the lower layer is dried and both layers are dried simultaneously. As for the liquid properties, the pH difference between the coating solution for the image forming layer and the coating solution for the protective layer is preferably 2.5 or less, and the smaller the pH difference, the more preferable. Coating solution pH
When the difference is large, micro-aggregation is likely to occur at the interface of the coating solution, and a serious surface failure such as a coating streak tends to occur during long continuous coating.

The coating solution viscosity of the image forming layer is 15 to 25 ° C.
100 mPa · s is preferred, and more preferably 40 to
70 mPa · s. On the other hand, the coating liquid viscosity of the protective layer is 2
The temperature is preferably 5 to 75 mPa · s at 5 ° C., and more preferably 30 to 60 mPa · s. These viscosities are measured by a B-type viscometer.

Winding after drying is preferably carried out under the conditions of a temperature of 20 to 30 ° C. and a relative humidity of 45 ± 20%. Good or inside. Further, when the processing form is a roll product, it is also preferable to use a roll form wound on the side opposite to the winding form at the time of processing in order to remove the curl generated in the winding form. The relative humidity of the photosensitive material is 20 to
It is preferable to control the temperature within a range of 55% (measured at 25 ° C.).

In a conventional photographic emulsion coating solution which is a viscous solution containing a silver halide and containing silver halide, bubbles are dissolved and disappear in the solution simply by sending the solution under pressure. Even when returned, there is almost no bubble deposition. However, in the case of an image forming layer coating solution containing an organic silver salt dispersion and a polymer latex, which are preferably used in the present invention, the defoaming tends to be insufficient only by pressurized liquid feeding, so that a gas-liquid interface does not occur. It is preferable to remove the bubbles by applying ultrasonic vibration while feeding the solution.

In the present invention, the defoaming of the coating solution is performed by deaeration under reduced pressure before the coating solution is applied, and further, 1.5 kg / cm ^2.
A method in which ultrasonic vibration is applied while maintaining the above-mentioned pressurized state and continuously feeding the liquid without generating a gas-liquid interface is preferable. Specifically, Japanese Patent Publication No. 55-6405 (4)
The method described on page 20, line 7 to page 7, line 11) is preferred. As an apparatus for performing such defoaming, JP-A-2000-2000
The apparatus shown in the embodiment of FIG. 3 and FIG. 3 can be preferably used.

The pressure is preferably 1.5 kg / cm ² or more, more preferably 1.8 kg / cm ² or more. There is no particular upper limit, but usually 5 kg / cm ²
It is about. The applied ultrasonic sound pressure is 0.2V or more,
It is preferably 0.5 V to 3.0 V, and generally it is preferable that the sound pressure is high. However, if the sound pressure is too high, the temperature becomes partially high due to caption, which causes fog. The frequency is not particularly limited, but is usually 10 kHz or more,
Preferably, it is 20 kHz to 200 kHz. In addition, decompression degassing refers to deaeration by increasing the bubble diameter in the coating solution, increasing the buoyancy, and deaeration by reducing the pressure inside the tank (usually a liquid preparation tank or a storage tank). Decompression conditions are -200 mmHg or lower pressure conditions,
The pressure condition is preferably -250 mmHg or lower, and the lowest pressure condition is not particularly limited, but is usually about -800 mmHg. Decompression time is 30 minutes or more,
It is preferably 45 minutes or more, and the upper limit is not particularly limited.

In the present invention, the image forming layer, the protective layer of the image forming layer, the undercoat layer and the back layer are described in JP-A-11-84.
No. 573, paragraphs 0204 to 0208;
Paragraph Nos. 0240 to 024 of 1-106881 specification
A dye can be contained for the purpose of preventing halation as described in 1.

Various dyes and pigments can be used in the image forming layer from the viewpoint of improving color tone and preventing irradiation. Although any dyes and pigments can be used for the image forming layer, for example, compounds described in paragraph No. 0297 of JP-A-11-119374 can be used. As a method for adding these dyes, any method such as a solution, an emulsion, a solid fine particle dispersion, and a state in which the dye is mordanted with a polymer mordant may be used. The amount of these compounds to be used is determined depending on the desired absorption amount, but it is generally preferable to use them in the range of 1 × 10 ⁻⁶ g to 1 g per 1 m ² .

When an antihalation dye is used in the present invention, the dye has a desired absorption in a desired range, has a sufficiently low absorption in the visible region after the treatment, and has a desirable absorbance spectrum shape of the back layer. Any compound can be used, if possible. For example, a compound described in paragraph No. 0300 of JP-A-11-119374 can be used. Further, as described in Belgian Patent No. 733,706, a method in which the concentration of a dye is reduced by discoloration by heating, or by discoloration by light irradiation as described in JP-A-54-17833. A method of reducing the concentration and the like can also be used.

When the photothermographic material of the present invention is used as a mask when preparing a printing plate using a PS plate after the heat development, the photothermographic material after the heat development is subjected to exposure conditions for the PS plate in a plate making machine. Information to set,
Information for setting plate-making conditions such as a transfer condition of a mask original and a PS plate is carried as image information. Therefore, said irradiation dye, halation dye,
The concentration (use amount) of the filter dye is limited to read them. Since this information is read by LED or laser, Dm of the wavelength range of the sensor
In (minimum concentration) needs to be low, and the absorbance needs to be 0.3 or less. For example, a plate making machine S-FNRIII manufactured by Fuji Photo Film Co., Ltd. uses a light source having a wavelength of 670 nm as a detector for detecting a register mark and a barcode reader. The plate making machine APM manufactured by Shimizu Seisakusho Co., Ltd.
A 670 nm light source is used as an L series barcode reader. That is, Dmin around 670 nm
When the (lowest density) is high, the information on the film cannot be detected accurately, and a work error occurs in the plate making machine such as a conveyance failure and an exposure failure. Therefore, in order to read information with a 670 nm light source, Dmin around 670 nm needs to be low, and the absorbance at 660 to 680 nm after thermal development needs to be 0.3 or less. More preferably, it is 0.25 or less. The lower limit is not particularly limited, but is usually about 0.10.

In the present invention, the exposure apparatus used for imagewise exposure may be any apparatus capable of performing exposure with an exposure time of 10 ⁻⁷ seconds or less. In general, a laser diode (LD) and a light emitting diode are generally used. An exposure apparatus using (LED) as a light source is preferably used. In particular, LD has high output,
More preferable in terms of high resolution. Any of these light sources may be used as long as it can generate light of an electromagnetic wave spectrum in a target wavelength range. For example, in the case of LD, a dye laser, a gas laser, a solid laser, a semiconductor laser, or the like can be used.

The exposure in the present invention is performed by overlapping the light beams of the light source. Overlap means that the sub-scanning pitch width is smaller than the beam diameter. For example, the overlap is determined by changing the beam diameter to a half value width (FW) of the beam intensity.
HM), it can be quantitatively expressed by FWHM / sub-scanning pitch width (overlap coefficient).
In the present invention, the overlap coefficient is preferably 0.2 or more.

The scanning method of the light source of the exposure apparatus used in the present invention is not particularly limited, and a cylinder outer surface scanning method, a cylinder inner surface scanning method, a plane scanning method, or the like can be used. Also,
The channel of the light source may be a single channel or a multi-channel, but a multi-channel having two or more laser heads is preferable in that high output is obtained and writing time is shortened. In particular, in the case of the cylindrical outer surface type, a multi-channel having several to several tens or more laser heads is preferably used.

The photothermographic material of the present invention has a low haze at the time of exposure and tends to generate interference fringes. As a technique for preventing the generation of the interference fringes, a technique disclosed in Japanese Patent Application Laid-Open No. Hei 5-113548, for example, in which a laser beam is obliquely incident on a photosensitive material, or WO95 / 3175.
A method using a multi-mode laser disclosed in, for example, Japanese Patent Application Laid-Open No. 4 (Kokai) No. 4 is known, and it is preferable to use these techniques.

The heat development step of the image forming method used in the present invention may be any method, but usually the image is exposed to the heat-developable photothermographic material and heated to develop. As a preferred embodiment of the thermal developing machine to be used, a type in which the photothermographic material is brought into contact with a heat source such as a heat roller or a heat drum is disclosed in Japanese Patent Publication No. 5-56499, Japanese Patent Application Laid-Open No. 9-292695, and Japanese Patent Application Laid-Open No. 9-297385. Developing machine described in Japanese Patent Application Laid-Open No. HEI 7-132 as a non-contact type.
No. 94, International Publication Nos. WO 97/28489, JP 97/28488 and JP 97/28487. A particularly preferred embodiment is a non-contact type thermal developing machine. The preferred development temperature is from 80 to 250C, more preferably from 100 to 14C.
0 ° C. The development time is preferably from 1 to 180 seconds, more preferably from 5 to 90 seconds. Line speed is 1
It is preferably at least 40 cm / min, more preferably at least 150 cm / min.

As a method for preventing processing unevenness due to a dimensional change of the photothermographic material during the heat development, a temperature of 80.degree.
It is effective to employ a method of heating at 5 ° C. or more so that an image is not formed at a temperature of less than 15 ° C., and then thermally developing at 110 ° C. to 140 ° C. to form an image (a so-called multi-step heating method). .

When the photothermographic material of the present invention is subjected to thermal development processing, it is exposed to a high temperature of 110 ° C. or more, so that a part of the components contained in the material or a part of the components decomposed by thermal development are removed. Volatilizes. These volatile components may cause uneven development, corrode the components of the heat developing machine, precipitate at low temperatures, cause deformation of the screen as foreign matter, and adhere to the screen and become dirty. Is known to have a bad effect. As a method for eliminating these effects, it is known to install a filter in the heat developing machine and optimally adjust the flow of air in the heat developing machine. These methods can be effectively used in combination. International Publication WO95 / 30933, 97
Japanese Patent Application Laid-Open No. 21150/1990 and Japanese Patent Application Laid-Open No. 10-500496 disclose a filter cartridge having a binding opening and a first opening for introducing volatile matter and a second opening for discharging the film. It is described to be used for a heating device for heating by heating. In addition, International Publication WO96 / 1
Japanese Patent Publication No. 2213 and Japanese Patent Publication No. Hei 10-507403 describe the use of a filter combining a thermally conductive condensation collector and a gas-absorbing fine particle filter. In the present invention, these can be preferably used. U.S. Pat. No. 4,518,845 and Japanese Patent Publication No. 3-54331 disclose a device for removing vapor from a film, a pressurizing device for pressing the film against a heat transfer member, and heating of the heat transfer member. A configuration having an apparatus for performing the above is described. In addition, International Publication WO98 / 27458 describes that a component that increases fog volatilized from a film is removed from the film surface. These can also be preferably used in the present invention.

FIG. 1 shows an example of the configuration of a heat developing machine used in the heat developing process of the photothermographic material of the present invention. FIG. 1 is a side view of the heat developing machine. The heat developing machine of FIG. 1 includes a carry-in roller pair 11 (an upper roller is a silicon rubber roller and a lower roller is an aluminum heat roller) for carrying the heat-developable photosensitive material 10 into a heating section while correcting and preheating the heat-developable photosensitive material 10 into a planar shape. It has a carry-out roller pair 12 that carries out the heat-developable photothermographic material 10 after the heat development to a flat shape and carries it out of the heating unit. The photothermographic material 10 has a carry-in roller pair 1
While being transported from 1 to the discharge roller pair 12, it is thermally developed. In the conveying means for conveying the photothermographic material 10 during the heat development, a plurality of rollers 13 are provided on the side where the surface having the image forming layer contacts, and the non-woven fabric (for example, Smooth surface 14 on which aromatic polyamide or Teflon (registered trademark) is bonded.
Is installed. The photothermographic material 10 is conveyed while the back surface is slid over the smooth surface 14 by driving a plurality of rollers 13 that come into contact with the surface having the image forming layer. A heater 1 is provided on the upper portion of the roller 13 and the lower portion of the smooth surface 14 so as to be heated from both sides of the photothermographic material 10.
5 is installed. As a heating means in this case, a plate heater or the like can be used. The clearance between the roller 13 and the smooth surface 14 varies depending on the member of the smooth surface, but is appropriately adjusted to a clearance that allows the photothermographic material 10 to be transported.
Preferably it is 0 to 1 mm.

Material of the Surface of Roller 13 and Smooth Surface 1
The member of No. 4 is durable at high temperature and may be anything as long as it does not hinder the conveyance of the photothermographic material 10, but the material of the roller surface is made of silicon rubber, and the member of the smooth surface is made of aromatic polyamide or Teflon (PTFE). Non-woven fabrics are preferred. A plurality of heaters as heating means, it is preferable to freely set the heating temperature, respectively.

The heating section is composed of a preheating section A having a carry-in roller pair 11 and a heat development heating section B having a heating heater 15, but a preheating section upstream of the heat development processing section B. A is lower than the heat development temperature (for example, 10 to 3).
(Lower by about 0 ° C.), it is desirable to set the temperature and time to be sufficient to evaporate the amount of water in the photothermographic material 10, and to be higher than the glass transition temperature (Tg) of the support of the photothermographic material 10. It is preferable to set the temperature so that uneven development does not occur. The temperature distribution of the preheating section and the heat development section is preferably ± 1 ° C. or less, more preferably ± 0.1 ° C.
5 ° C. or lower is preferred. Further, a guide plate 16 is provided downstream of the thermal development processing section B, and a slow cooling section C having the carry-out roller pair 12 and the guide plate 16 is provided. Guide plate 16
Is preferably a material having a low thermal conductivity.
The cooling is preferably performed gradually so as not to cause deformation, and the cooling rate is preferably 0.5 to 10 ° C./sec.

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

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The present invention will be described more specifically with reference to the following examples. Materials, reagents, ratios, operations, and the like shown in the following examples can be appropriately changed without departing from the gist of the present invention. Therefore, the scope of the present invention is not limited to the following specific examples.

Example 1 << Preparation of Silver Halide Emulsion A >> Alkali-treated gelatin (2700 ppm in terms of calcium content) was added to 700 ml of water.
The following) 11 g, 30 mg of potassium bromide and 1.3 g of sodium 4-methylbenzenesulfonate were dissolved and the pH was adjusted to 6.5 at a temperature of 45 ° C., and then 18.6 of silver nitrate
g of aqueous solution containing 159 ml of potassium bromide and 1 mol /
L, 5 × 10 ⁻⁶ mol of (NH ₄ ) ₂ RhCl ₅ (H ₂ O)
/ L and an aqueous solution containing K ₃ IrCl ₆ at 2 × 10 ⁻⁵ mol / L were added over 6 minutes and 30 seconds by the control double jet method while maintaining the pAg at 7.7. Then, 476 ml of an aqueous solution containing 55.5 g of silver nitrate, 1 mol / L of potassium bromide and 2 × 10 ⁻⁵ mol of K ₃ IrCl _6.
/ L was added over 28 minutes and 30 seconds by the control double jet method while maintaining the pAg at 7.7. Thereafter, the pH was lowered to perform coagulation sedimentation and desalting treatment, and 51.1 g of low molecular weight gelatin having an average molecular weight of 15,000 (calculated as 20 ppm or less).
In addition, it was adjusted to pH 5.9 and pAg 8.0. The obtained particles were cubic particles having an average particle size of 0.11 μm, a projected area variation coefficient of 9%, and a (100) plane ratio of 90%.
The silver halide grains thus obtained were heated to 60 ° C.
Sodium benzenethiosulfonate 76μ per mol
mol, and after 3 minutes, triethylthiourea 71 μm
After aging for 100 minutes, 5 × 10 ⁻⁴ mol of 4-hydroxy-6-methyl-1,3,3a, 7-tetrazaindene and 0.17 g of compound A were added, followed by 4 hours.
The temperature was lowered to 0 ° C. Thereafter, the temperature was maintained at 40 ° C., and 4.7 × 10 ⁻² mol of potassium bromide (added as an aqueous solution) per 1 mol of silver halide, 12.8 × 10 ⁻⁴ mol.
l of the following sensitizing dye A (added as an ethanol solution),
6.4 × 10 ⁻³ mol of compound B (added as a methanol solution) was added with stirring, and after 20 minutes, the mixture was rapidly cooled to 30 ° C. to complete the preparation of silver halide emulsion A.

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<< Preparation of Silver Behenate Dispersion A >> Behenic acid (product name: Edenor C22-85R) 8 manufactured by Henkel Co.
7.6 kg, 423 L of distilled water, 5 mol / L NaOH
49.2 L of aqueous solution, tert-butyl alcohol 120
Were mixed and reacted at 75 ° C. for 1 hour with stirring to obtain a sodium behenate solution. Separately, 206.2 L of an aqueous solution of 40.4 kg of silver nitrate was prepared and kept at 10 ° C. 6
A reaction vessel containing 35 L of distilled water and 30 L of tert-butyl alcohol was kept at 30 ° C., and while stirring, the entire amount of the sodium behenate solution and the entire amount of the silver nitrate aqueous solution were kept at a constant flow rate for 62 minutes, 10 seconds and 60 minutes, respectively. Added over minutes. At this time, only the silver nitrate aqueous solution was added for 7 minutes and 20 seconds after the addition of the silver nitrate aqueous solution was started, and then the addition of the sodium behenate solution was started. It was made to be added. At this time, the temperature inside the reaction vessel was 30 ° C.
And the solution temperature was controlled so as not to rise. The piping of the addition system of the sodium behenate solution was kept warm by steam tracing, and the amount of steam was controlled so that the liquid temperature at the outlet at the tip of the addition nozzle became 75 ° C. The piping of the silver nitrate aqueous solution addition system was kept warm by circulating cold water outside the double pipe. The addition position of the sodium behenate solution and the addition position of the aqueous silver nitrate solution were arranged symmetrically with respect to the stirring axis, and were adjusted to a height such that they did not come into contact with the reaction solution.

After the addition of the sodium behenate solution was completed, the mixture was left to stir at the same temperature for 20 minutes, and the temperature was lowered to 25 ° C. Thereafter, the solid content was separated by centrifugal filtration, and the solid content was washed with water until the conductivity of the filtrate became 30 μS / cm. The solid thus obtained was stored as a wet cake without drying.

The morphology of the obtained silver behenate grains was evaluated by electron microscopic photographing.
It was a flaky crystal having a particle size of 2 μm, an average particle thickness of 0.14 μm, and a coefficient of variation of the average equivalent sphere diameter of 15%.

Next, a dispersion of silver behenate was prepared by the following method. For a wet cake equivalent to 100 g of dry solids, polyvinyl alcohol (trade name: PVA-21)
7, average degree of polymerization: about 1700) and water were added to make the total amount 385 g, and the mixture was predispersed with a homomixer. Next, the pre-dispersed undiluted solution is dispersed in a dispersing machine (trade name:
The pressure of a microfluidizer M-110S-EH, manufactured by Microfluidics International Corporation, using a G10Z interaction chamber) was adjusted to 1750 kg / cm ² , and the mixture was treated three times to obtain a silver behenate dispersion A. In the cooling operation, a coiled heat exchanger was mounted before and after the interaction chamber, and the temperature of the refrigerant was adjusted to a desired dispersion temperature.

The silver behenate particles contained in the silver behenate dispersion A thus obtained were particles having a volume-weighted average diameter of 0.52 μm and a coefficient of variation of 15%. Measurement of particle size
Performed with MasterSizerX manufactured by lvern Instruments Ltd. When evaluated by electron microscopy, the ratio of the long side to the short side was 1.5, the grain thickness was 0.14 μm, and the average aspect ratio (the ratio of the circle equivalent diameter of the projected area of the grain to the grain thickness) was 5.1. Was.

<< 1,1-bis (2-hydroxy-3,5)
-Dimethylphenyl) -3,5,5-trimethylhexane: Preparation of solid fine particle dispersion of reducing agent >> 1,1-bis (2-hydroxy-3,5-dimethylphenyl) -3,
Surfynol 104E was added to 10 kg of 5,5-trimethylhexane and 10 kg of a 20% by mass aqueous solution of modified polyvinyl alcohol (Poval MP203, manufactured by Kuraray Co., Ltd.).
400 g (manufactured by Nissin Chemical Co., Ltd.) and 640 methanol
g and 16 kg of water were added and mixed well to form a slurry. The slurry was sent by a diaphragm pump and dispersed in a horizontal bead mill (UVM-2, manufactured by Imex Co., Ltd.) filled with zirconia beads having an average diameter of 0.5 mm for 3 hours 30 minutes, and then sodium benzoisothiazolinone sodium salt was added. 4 g and water were added to adjust the concentration of the reducing agent to 25% by mass to obtain a solid fine particle dispersion of the reducing agent. The reducing agent particles contained in the dispersion thus obtained have a median diameter of 0.1.
44 μm, the maximum particle size was 2.0 μm or less, and the variation coefficient of the average particle size was 19%. The resulting dispersion has a pore size of 3.0μ.
Then, the mixture was filtered with a polypropylene filter of m to remove foreign substances such as dust, and stored.

<< Preparation of Solid Fine Particle Dispersion of Organic Polyhalogen Compound A >> Organic polyhalogen compound A: 10 kg of tribromomethyl (4- (2,4,6-trimethylphenylsulfonyl) phenyl) sulfone and modified polyvinyl alcohol ( 10 kg of a 20% by weight aqueous solution of Kuraray Co., Ltd., Poval MP203) and 639 g of a 20% by weight aqueous solution of sodium triisopropylnaphthalenesulfonate
And Surfynol 104E (Nissin Chemical Co., Ltd.) 40
0 g, 640 g of methanol and 16 kg of water,
Mix well to form a slurry. This slurry was fed by a diaphragm pump, and a horizontal bead mill filled with zirconia beads having an average diameter of 0.5 mm (IMEX Co., Ltd.)
And UVM-2) for 5 hours, and water was added to adjust the concentration of the organic polyhalogen compound A to 25% by mass to obtain a solid fine particle dispersion of the organic polyhalogen compound A. The organic polyhalogen compound particles contained in the dispersion thus obtained had a median diameter of 0.36 μm, a maximum particle diameter of 2.0 μm or less, and an average particle diameter variation coefficient of 18%. The obtained 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 Solid Fine Particle Dispersion of Organic Polyhalogen Compound B >> Organic polyhalogen compound B: 20% by mass aqueous solution of 5 kg of tribromomethylnaphthyl sulfone and modified polyvinyl alcohol (Poval MP203, manufactured by Kuraray Co., Ltd.) 5 kg, and 213 g of a 20% by mass aqueous solution of sodium triisopropylnaphthalenesulfonate,
10 kg of water was added and mixed well to form a slurry.
This slurry was sent by a diaphragm pump and dispersed for 5 hours in a horizontal bead mill (UVM-2, manufactured by Imex Co., Ltd.) filled with zirconia beads having an average diameter of 0.5 mm. 5
g and water, the concentration of the organic polyhalogen compound B is 2
It was adjusted to 3.5% by mass to obtain a solid fine particle dispersion of the organic polyhalogen compound B. The organic polyhalogen compound particles contained in the dispersion thus obtained had a median diameter of 0.38 μm, a maximum particle diameter of 2.0 μm or less, and a coefficient of variation of the average particle diameter of 20%. The resulting dispersion has a pore size of 3.
After filtration through a 0 μm polypropylene filter,
Foreign matter such as dust was removed and stored.

<< Preparation of Aqueous Solution of Organic Polyhalogen Compound C >> While stirring at room temperature, 75.0 ml of water and sodium tripropylnaphthalenesulfonate (20% aqueous solution)
8.6 ml, sodium dihydrogen orthophosphate dihydrate (5% aqueous solution) 6.8 ml, potassium hydroxide (1 mol
/ L aqueous solution) was added in order, and the mixture was stirred and mixed for 5 minutes after completion of the addition. Further, while stirring, 4.0 g of powder of organic polyhalogen compound C (3-tribromomethanesulfonylbenzoylaminoacetic acid) was added and uniformly dissolved until the solution became transparent to obtain 100 ml of an aqueous solution. The obtained aqueous solution was filtered through a 200-mesh polyester screen to remove foreign substances such as dust, and stored.

<< Preparation of Solid Fine Particle Dispersion of Organic Polyhalogen Compound D >>
12 kg of a 10% by mass aqueous solution of a modified polyvinyl alcohol (manufactured by Kuraray Co., Ltd., Poval MP203) and 20% by mass of sodium triisopropylnaphthalenesulfonate
240 g of an aqueous solution and 0.18 kg of water were added and mixed well to form a slurry. This slurry was fed by a diaphragm pump and filled with zirconia beads having an average diameter of 0.5 mm in a horizontal bead mill (manufactured by Imex Co., Ltd.).
After dispersion for 5 hours with UVM-2), 2 g of sodium benzoisothiazolinone and water were added to adjust the concentration of the organic polyhalogen compound D to 30% by mass, and solid fine particles of the organic polyhalogen compound D were prepared. A dispersion was obtained. The organic polyhalogen compound particles contained in the dispersion thus obtained had a median diameter of 0.40 μm, a maximum particle diameter of 2.0 μm or less, and a coefficient of variation of the average particle diameter of 20%. The obtained 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 Emulsified Dispersion of Compound Z >> Compound Z
10% of R-054 manufactured by Sanko Co., Ltd. containing 85% by mass of
g and MIBK (11.66 kg) were mixed, and then replaced with nitrogen and dissolved at 80 ° C. for 1 hour. 25.52 kg of water in this liquid
12.76 kg of a 20% by mass aqueous solution of MP-203, a MP polymer manufactured by Kuraray Co., Ltd., and 0.44k of a 20% by mass aqueous solution of sodium triisopropylnaphthalenesulfonate
g was added and emulsified and dispersed at 20 to 40 ° C. and 3600 rpm for 60 minutes. In addition, Surfynol 10
0.08 kg of 4E (manufactured by Nissin Chemical Co., Ltd.) and 47.94 of water
After addition of kg and vacuum distillation to remove MIBK, the compound Z was adjusted to a concentration of 10% by mass. The particles of compound Z contained in the dispersion thus obtained had a median diameter of 0.19 μm, a maximum particle diameter of 1.5 μm or less, and a variation coefficient of the particle diameter of 17%. The resulting dispersion had a pore size of 3.0.
Filtration was performed with a μm polypropylene filter to remove foreign substances such as dust, and stored.

<< Preparation of Dispersion of 6-Isopropylphthalazine Compound >> Modified polyvinyl alcohol (Poval M, manufactured by Kuraray Co., Ltd.) was stirred at room temperature with 62.35 g of water.
P203) 2.0 g was added so as not to form a lump, and the mixture was stirred and mixed for 10 minutes. Thereafter, the mixture was heated and heated up to an internal temperature of 50 ° C., and then stirred for 90 minutes at an internal temperature of 50 to 60 ° C. to be uniformly dissolved. The internal temperature was lowered to 40 ° C. or less, and polyvinyl alcohol (manufactured by Kuraray Co., Ltd., PVA-217,
25.5 g of a 10% by mass aqueous solution), 3.0% of sodium tripropylnaphthalenesulfonate (a 20% by mass aqueous solution).
g, 6-isopropylphthalazine (70% by mass aqueous solution)
7.15 g was added, and the mixture was stirred for 30 minutes and 100 g of a transparent dispersion was added.
I got The obtained 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 Solid Fine Particle Dispersion of Compound Corresponding to (1) >> The compound (kind shown in Table 13) corresponding to any of (1) to (4 kg) was added to Poval PVA- manufactured by Kuraray Co., Ltd. 217 1kg and water 36k
g was added and mixed well to obtain a slurry. This slurry is sent by a diaphragm pump and has an average diameter of 0.5 m.
m for 12 hours in a horizontal bead mill (UVM-2, manufactured by Imex Co., Ltd.) filled with zirconia beads, and then adding 4 g of benzoisothiazolinone sodium salt and water to the concentration of the compound corresponding to any of Was adjusted to 10% by mass to obtain a solid fine particle dispersion of the compound. Particles of the compound corresponding to any of the above-mentioned contained in the dispersion thus obtained have a median diameter of 0.34 μm,
The maximum particle size was 3.0 μm or less, and the variation coefficient of the particle size was 19%. The obtained 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 Solid Fine Particle Dispersion of Development Accelerators W1 and W2 >> 10 kg of development accelerator W1 and modified polyvinyl alcohol (Poval MP203, manufactured by Kuraray Co., Ltd.)
10 kg of a 20% by mass aqueous solution and 20 kg of water were added and mixed well to form a slurry. This slurry was fed by a diaphragm pump, and a horizontal bead mill (IMEX) filled with zirconia beads having an average diameter of 0.5 mm was used.
After dispersing for 5 hours with UVM-2), water was added to adjust the concentration of the development accelerator W1 to 20% by mass to obtain a solid fine particle dispersion of the development accelerator W1. The organic polyhalogen compound particles contained in the dispersion thus obtained had a median diameter of 0.5 μm, a maximum particle diameter of 2.0 μm or less, and an average particle diameter variation coefficient of 18%. The obtained dispersion was filtered through a polypropylene filter having a pore size of 3.0 μm to remove foreign substances such as dust, and stored. Regarding the development accelerator W2, a solid fine particle dispersion was obtained in the same manner as described above.

<< Preparation of Image Forming Layer Coating Solution >> The following binder, material and silver halide emulsion A were added to 1 mol of silver of silver behenate dispersion A prepared above, and water was added. And an image forming layer coating solution. After completion, degassing under reduced pressure was performed at a pressure of 0.54 atm for 45 minutes. The coating solution has a pH of 7.3 to 7.6 and a viscosity of 48 to 58 m at 25 ° C.
Pa · s. Binder; SBR latex [St / Bu / AA = 68/29/3 (% by mass), glass transition temperature: 17 ° C. (calculated value), types of polymerization initiator and pH adjuster are described in Table 13, average particle diameter Is 112 to 124 nm, and the pH is adjusted to 6.5, and the I / O value is 0.11.] 397 g as solids 1,1-bis (2-hydroxy-3,5-dimethylphenyl) -3,5 , 5-Trimethylhexane 150.0 g as solid content Organic polyhalogen compound A 42.8 g as solid content Organic polyhalogen compound B 14.1 g as solid content Organic polyhalogen compound C 2.3 g as solid content Development accelerator W1 Solid content 5.5 g sodium ethylthiosulfonate 0.3 g benzotriazole 1.1 g polyvinyl alcohol (Kuraray Co., Ltd., PV -235) 10.9 g 6-isopropylphthalazine 12.9 g Compound Z 9.7 g as solids Compound C 2.0 g Compound corresponding to any of the above (types shown in Table 13) 9.0 g as solids A (added as a mixture with low molecular weight gelatin having an average molecular weight of 15,000) Coating amount at which optical density at 783 nm becomes 0.3 (solid content: 0.40 g as a guide) Silver halide emulsion Ag content: 0.06 mol Antiseptic Compound A as an agent 40 ppm in coating solution (2.5 mg / m ² as coating amount) 1% by mass as total solvent amount in coating solution of methanol 2% by mass as total solvent amount in coating solution of ethanol

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<< Preparation of Coating Solution for Lower Layer of Protective Layer >> Polymer latex shown in Table 13 (solid content: 28.0%, glass transition temperature: 25 to 33 ° C. [calculated value], average particle size: 100 to 1)
20 nm) to 901 g of water, 0.2 g of compound E,
Polyvinyl alcohol (Kuraray Co., Ltd., PVA-23
5) 18.7 g and further water were added to prepare a coating solution (containing 0.5% by mass of a methanol solvent). After completion, deaeration under reduced pressure was performed at a pressure of 0.47 atm for 60 minutes. Coating liquid p
H is 5.1 to 6.5, viscosity is 25 to 36 mPa at 25 ° C.
-It was s.

<< Preparation of Coating Solution for Upper Layer of Protective Layer >> Polymer latex shown in Table 13 (solid content: 28.0%, glass transition temperature: 30 to 33 ° C. [calculated value], average particle size: 100 to 1)
Water was added to 688 g of 20 nm), 9.4 g of a 30% by mass solution of carnava wax (manufactured by Chukyo Yushi Co., Ltd., cellosol 524: less than 5 ppm in terms of silicone content), 0.2 g of compound C, and 2.0 g of compound E , Compound F with 2
1.7 g, 4.8 g of compound H, matting agent (polystyrene particles, average particle diameter 7 μm, coefficient of variation of average particle diameter 8%)
3.4 g and polyvinyl alcohol (Kuraray Co., Ltd.)
Co., PVA-235) was added, and water was further added to prepare a coating solution (containing 1.5% by mass of a methanol solvent). After completion, vacuum degassing is performed at a pressure of 0.47 atm for 60
Minutes. The coating solution has a pH of 2.3 to 2.9 and a viscosity of 2
It was 21 to 34 mPa · s at 5 ° C.

[0173]

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<< Preparation of Polyethylene Terephthalate (PET) Support with Back / Undercoat Layer >> (1) Preparation of PET Support Using terephthalic acid and ethylene glycol, the intrinsic viscosity IV = 0.66 (phenol / Tetrachloroethane = 6/4 (measured at 25 ° C in mass ratio)). This was pelletized, dried at 130 ° C. for 4 hours, and then melted at 300 ° C.
After being extruded from the die, it is quenched and the film thickness after heat setting is 12
An unstretched film having a thickness of 0 μm was produced.
This is longitudinally stretched 3.3 times using rolls with different peripheral speeds.
Then, a transverse stretching was performed 4.5 times with a tenter. The temperatures at this time were 110 ° C. and 130 ° C., respectively. After that, it was heat-set at 240 ° C. for 20 seconds, and relaxed 4% in the horizontal direction at the same temperature. Then, after slitting the chuck portion of the tenter, knurling is performed on both ends, and 4.8 k
g / cm ² . Thus, the width 2.4
m, length 3500 m, thickness 120 μm, roll-shaped PE
A T support was obtained.

(2) Preparation of Undercoat Layer and Back Layer Undercoat First Layer After subjecting the PET support to a corona discharge treatment at 0.375 kV · A · min / m ² , a coating solution having the following composition was applied to the PET support. .2 ml / m ² on a support,
C. for 30 seconds, 150.degree. C. for 30 seconds, and 185.degree. C. for 30 seconds.

Latex-A 280 g KOH 0.5 g Polystyrene fine particles (average particle diameter: 2 μm, coefficient of variation of average particle diameter 7%) 0.03 g 2,4-dichloro-6-hydroxy-s-triazine 1.8 g Compound— Bc-C 0.097g Distilled water Amount that total amount becomes 1000g

Second layer of undercoat A coating solution having the composition shown below was applied on the first layer of undercoat so as to have a concentration of 5.5 ml / m ^2.
It dried at 30 degreeC for 30 second and 170 degreeC for 30 second.

Deionized gelatin (Ca ²⁺ content: 0.6 ppm, jelly strength: 230 g) 10 g Acetic acid (20% by mass aqueous solution) 10 g Compound-Bc-A 0.04 g Methyl cellulose (2% by mass aqueous solution) 25 g Polyethyleneoxy compound 3g Distilled water Amount that totals 1000g

Back first layer: 0.375 kV · V on the surface opposite to the undercoat layer application surface
Subjected to corona discharge treatment of A · min / m ^2, by coating a coating solution having the following composition in its surface as a 13.8ml / m ^2, 30 seconds at 125 ° C., 30 seconds at 0.99 ° C., 185 Dry at 30 ° C. for 30 seconds.

Julimer ET410 (30% by mass aqueous dispersion, manufactured by Nippon Pure Chemical Co., Ltd.) 23 g Alkali-treated gelatin (molecular weight: about 10,000, Ca ²⁺ content: 30 ppm) 4.44 g Deionized gelatin (Ca ²⁺ content: 0.4%) 0.84 g Compound-Bc-A 0.02 g Dye-Bc-A (adjusted to an optical density of 1.33 to 1.4 at 783 nm) As a guide 0.88 g Polyoxyethylene phenyl ether 1.7 g Water-soluble melamine compound (Sumitomo Chemical Co., Ltd., Sumitex Resin M-3, 8% by mass aqueous solution) 15 g Water dispersion of needle-like particles of Sb-doped SnO ₂ (FS-10D, manufactured by Ishihara Sangyo Co., Ltd.) 24 g polystyrene fine particles (average particle size: 2 μm, coefficient of variation of average particle size: 7%) 0.03 g distilled water The amount of the total amount becomes 1000 g

Back second layer A coating solution having the following composition was applied onto the first back layer so as to have a concentration of 5.5 ml / m ^2, and was applied at 125 ° C. for 30 seconds at 150 ° C.
For 30 seconds and 170 ° C. for 30 seconds.

Julimer ET410 (30% by mass aqueous dispersion, manufactured by Nippon Pure Chemical Co., Ltd.) 57.5 g Polyoxyethylene phenyl ether 1.7 g Water-soluble melamine compound (Sumitec Resin M-, manufactured by Sumitomo Chemical Co., Ltd.) 3,8% by mass aqueous solution) 15g Cellosol 524 (30% by mass aqueous solution, manufactured by Chukyo Yushi Co., Ltd.) 6.6g Distilled water Amount that gives a total amount of 1000g

Back third layer The same coating solution as that for the first undercoat layer was applied onto the second back layer so as to have a concentration of 6.2 ml / m ^2.
C. for 30 seconds and 185.degree. C. for 30 seconds.

Fourth Back Layer A coating solution having the composition shown below was applied onto the third back layer so as to have a concentration of 13.8 ml / m ^2, and was applied at 125 ° C. for 30 seconds for 150 seconds.
It dried at 30 degreeC for 30 second and 170 degreeC for 30 second.

Latex-B 286 g Compound-Bc-B 2.7 g Compound-Bc-C 0.6 g Compound-Bc-D 0.5 g 2,4 Dichloro-6-hydroxy-s-triazine 2.5 g Polymethyl methacrylate (10 Mass% aqueous dispersion, average particle diameter 5 μm, coefficient of variation of average particles 7%) 7.7 g distilled water Total amount of 1000 g

[0186]

Embedded image

Latex-A: Core-shell type latex core having 90% by mass of core and 10% by mass of shell: vinylidene chloride / methyl acrylate / methyl methacrylate / acrylonitrile / acrylic acid = 93/3
/3/0.9/0.1 (mass%) Shell part: vinylidene chloride / methyl acrylate / methyl methacrylate / acrylonitrile / acrylic acid = 8
8/3/3/3/3 (% by mass) Weight average molecular weight 38,000 Latex-B: methyl methacrylate / styrene / 2
-Ethylhexyl acrylate / 2-hydroxyethyl methacrylate / acrylic acid = 59/9/26/5/1
(% By mass of copolymer)

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

<< Preparation of Photothermographic Material >> On the undercoat layer of the PET support on which the first undercoat layer and the second undercoat layer are coated, the method is disclosed in FIG. 1 of JP-A-2000-2964. Using the above-mentioned slide beat coating method, the above-mentioned image forming layer coating solution was coated such that the coated silver amount became 1.5 g / m ² .
The coating liquid for the lower layer of the protective layer (the latex type is described in Table 13) is further coated thereon so that the solid content of the polymer latex is 1.1 g / m ^2, and the coating liquid for the upper layer of the protective layer is further coated thereon. (Latex species are described in Table 13) so that the solid content of the polymer latex is 1.3 g / m ² .
The image forming layer and the protective layer, the lower layer and the upper layer, were simultaneously coated in three layers. Drying conditions at the time of application are as follows: the first drying zone (low-speed air drying area) has a dry bulb temperature of 70 to 75 ° C, a dew point of 9 to 23 ° C
Wind velocity 8 to 10 m / s on support surface, liquid film surface temperature 35
Drying in the range of ４０40 ° C., the second drying zone (high-speed air drying area) is dried at a dry bulb temperature of 65 to 70 ° C., a dew point of 20 to 23 ° C., and a wind speed on the support surface of 20 to 25 m / s. did. The residence time in the first drying zone is 2/3 of the constant-rate drying period in this zone, and is shifted to the second drying zone,
Dried. The first drying zone is a horizontal drying zone (the support is at an angle of 1.5 ° to 3 ° with respect to the horizontal direction of the coating machine). The coating speed was 60 m / min. Winding after drying was performed under the conditions of a temperature of 25 ± 5 ° C. and a relative humidity of 45 ± 10%. The winding shape was adjusted to the subsequent processing form (image forming layer surface side outer winding), and the image forming layer surface side was turned out. The envelope humidity of the photothermographic material is 20 to 40% relative humidity (25%).
Of the resulting photothermographic material, the pH of the film surface on the image forming side is 5.1 to 5.3, and the Beck smoothness is 4700 to 4
It was 900 seconds, the pH of the opposite film surface was 5.9, and the Beck smoothness was 510 seconds.

<< Evaluation of Photographic Performance >> (Exposure Processing) The obtained photothermographic material was equipped with a semiconductor laser having a beam diameter (FWHM of ビ ー ム of the beam intensity) of 12.56 μm, a laser output of 50 mW, and an output wavelength of 783 nm. Using the single-channel cylindrical inner surface type laser exposure apparatus described above, exposure was performed at a mirror rotation number of 60000 rpm and an exposure time of 1.2 × 10 ⁻⁸ seconds. At this time, the overlap coefficient was 0.449, and the laser energy density on the photothermographic material surface was 75 μJ / cm ² .

(Heat Developing Process) The exposed photothermographic material was subjected to a heat developing process using the heat developing machine shown in FIG. The roller surface material of the thermal development processing section is silicon rubber,
The smooth surface was made of Teflon nonwoven fabric, and the line speed of the conveyance was set at 150 cm / min. Preheating section 12.2
Seconds (The drive systems of the preheating unit and the heat development unit are independent, and the speed difference between the heat development unit and the heat development unit is set to -0.5% to -1%.
The temperature setting and time of the metal roller of each preheating section are as follows: the first roller temperature is 67 ° C, 2.0 seconds, the second roller temperature is 82 ° C,
2.0 seconds, third roller temperature 98 ° C, 2.0 seconds, fourth roller temperature 107 ° C, 2.0 seconds, fifth roller temperature 115 ° C, 2.0 seconds, sixth roller temperature 120 ° C, .
0 sec), a heat development process was performed at 120 ° C. (surface temperature of the photothermographic material) for 17.2 seconds, and a slow cooling unit was performed for 13.6 seconds. The temperature accuracy in the width direction was ± 0.5 ° C. The temperature of each roller was set to be 5 cm longer on both sides than the width of the photothermographic material (for example, 61 cm in width), and the temperature was applied to that portion so that the temperature accuracy was improved.
In addition, since the temperature drop at both ends of each roller is severe,
The part that is 5 cm longer than the width of the photothermographic material is set so that the temperature is 1-3 ° C. higher than the center of the roller,
Care was taken so that the image density of the photothermographic material (for example, within a width of 61 cm) was uniform.

(Quantitative Determination of NH ₄ ⁺ Ion Content in Latex) The quantitative determination was carried out according to the method described in the text, and the results are shown in Table 13.

(Evaluation of photographic performance) For Dmin (fog) and Dmax (maximum density) of images, Macbeth TD
The measurement was performed using a 904 densitometer (visible density). As for the developed silver particle density, a photograph was taken, the number of developed silver particles per unit area was counted, and the densities were compared in the same manner as in the method described in the embodiment of the invention. The covering power is also a value obtained by dividing the visible density by the amount of developed silver (g / m ² ) for the sample in which all silver ions in the photosensitive material have been reduced, as in the method described in the embodiment of the invention. Was compared.

(Evaluation of White Powder Generation) In the case where the sample was exposed to light: The sample was developed using the heat developing machine shown in FIG.
After standing for a period of time, the sample was placed in a sealed bag, heat-treated at 50 ° C. for 3 days, and the presence or absence of white powder on the sample surface was evaluated by a 5-point method. In the case where the sample was not exposed to light: After the sample was developed using the heat developing machine shown in FIG.
After leaving for a period of time, the sample was placed in a sealed bag, heat-treated at 45 ° C. for 3 days, and the presence or absence of white powder on the sample surface was evaluated by a 5-point method. 5 ... Yes 4 ... Somewhat 2 ... Somewhat 0 ... No "3" is an intermediate level between "4" and "2" and "1" is an intermediate level between "2" and "0" Level, and practically needs to be “1” or “0”.

(Evaluation of Adhesion between Image Forming Layer and Protective Layer)
In the same manner as in the evaluation of the generation of white powder, an adhesive tape was attached to the surface of the sample subjected to the heat development treatment, the adhesive tape was peeled off at a constant speed, and the degree of peeling of the protective layer at that time was evaluated by a five-point method. Practically, it needs to be “5” or “4”. 5: No peeling 4: Peeling area is 1/4 or less of the sample 3 ... Peeling area is larger than 1/4 of the sample and 1/2 or less 2 ... Peeling area is more than 1/2 of the sample Large 3/4 or less 1 ... The peeling area is larger than 3/4 (including the whole peeling)

Table 13 shows the results of the above evaluation.

As is clear from Table 13, the samples satisfying the conditions of the present invention have good adhesiveness between the image forming layer after thermal development and the protective layer thereover, and have the presence or absence of light exposure before processing. Regardless, the generation of white powder can be prevented, the density of developed silver particles and the covering power are high, and it can be seen that they are excellent in terms of fog and Dmax. In addition, it can be seen that the comparative sample using a latex in which the content of NH ₄ ⁺ ions in the latex is higher than 50 ppm with respect to the solid content cannot prevent generation of white powder in a portion where there is no exposure before treatment.

[0198]

[Table 13]

Example 2 << Preparation of Coating Solution for Image Forming Layer >> The following binder, material, and silver halide emulsion A were added to 1 mol of silver of silver behenate dispersion A prepared in Example 1. Then, water was added to obtain an image forming layer coating solution. After completion, degassing under reduced pressure was performed at a pressure of 0.54 atm for 45 minutes. The coating solution has a pH of 7.3 to 7.7 and a viscosity of 49 to 60 mPa · s at 25 ° C.
Met.

Binder; SBR latex [St / Bu / AA = 68/29/3 (% by mass), glass transition temperature: 17 ° C. (calculated value), types of polymerization initiator and pH adjuster are described in Table 14, The average particle diameter is 112 to 124 nm, and the pH is adjusted to 6.5, and the I / O value is 0.11.] 397 g as solid content 1,1-bis (2-hydroxy-3,5-dimethylphenyl) − 3,5,5-trimethylhexane 117 g as solid content Organic polyhalogen compound B 11.9 g as solid content Organic polyhalogen compound D 39.8 g as solid content Development accelerator W2 11.6 g as solid content sodium ethyl thiosulfonate 0 0.3 g Benzotriazole 1.1 g Polyvinyl alcohol (manufactured by Kuraray Co., Ltd., PVA-235) 10.9 g 6-isopro Luphthalazine 12.9 g Sodium dihydrogen orthophosphate dihydrate 0.4 g Compound Z 9.7 g Compound C 2.0 g Compound X Solid content 5.0 g Dye A (Low molecular weight gelatin having an average molecular weight of 15,000) Coating amount at which the optical density at 783 nm becomes 0.3 (solid content: 0.40 g) Silver halide emulsion Ag amount: 0.06 mol Preservative: 40 ppm in compound A coating solution (coating amount) 2.5 mg / m ² ) 1% by mass of total solvent in methanol coating solution 2% by mass of total solvent in ethanol coating solution

<< Preparation of Coating Solution Under Protective Layer >> Polymer latex shown in Table 14 (solid content: 28.0%, glass transition temperature: 25 to 33 ° C. [calculated value], average particle size: 100 to 1)
20 nm) to 901 g of water, 0.2 g of compound E,
Polyvinyl alcohol (Kuraray Co., Ltd., PVA-23
5) 18.7 g and further water were added to prepare a coating solution (containing 0.5% by mass of a methanol solvent). After completion, deaeration under reduced pressure was performed at a pressure of 0.47 atm for 60 minutes. Coating liquid p
H is 5.1 to 6.3, viscosity is 24 to 36 mPa at 25 ° C.
-It was s.

<< Preparation of Coating Solution for Upper Layer of Protective Layer >> Polymer latex shown in Table 14 (solid content: 28.0%, glass transition temperature: 30 to 33 ° C. [calculated value], average particle size: 100 to 1)
Water was added to 688 g of 20 nm), 9.4 g of a 30% by mass solution of carnava wax (manufactured by Chukyo Yushi Co., Ltd., cellosol 524: less than 5 ppm in terms of silicone content), 0.2 g of compound C, and 2.0 g of compound E , Compound F with 2
1.7 g, 4.8 g of compound H, matting agent (polystyrene particles, average particle diameter 7 μm, coefficient of variation of average particle diameter 8%)
3.4 g and polyvinyl alcohol (Kuraray Co., Ltd.)
Co., PVA-235) was added, and water was further added to prepare a coating solution (containing 1.5% by mass of a methanol solvent). After completion, vacuum degassing is performed at a pressure of 0.47 atm for 60
Minutes. The coating solution has a pH of 2.3 to 2.9 and a viscosity of 2
It was 21 to 34 mPa · s at 5 ° C.

<< Preparation of Photothermographic Material >> In the same manner as in Example 1, the above-mentioned coating solution for the image forming layer was coated with a coating amount of 1.5 g / g.
m ^2, and the coating solution for the lower layer of the protective layer (latex type is described in Table 14) is further applied thereon so that the solid content of the polymer latex is 1.1 g / m ^2. The protective layer upper layer coating solution (latex type is described in Table 14) was coated with a solid content of 1.3 g / polymer latex.
The image forming layer, the lower layer and the upper layer of the protective layer were simultaneously coated so as to obtain m ² . The drying conditions and winding appearance at the time of coating were the same as in Example 1, and the image forming layer surface side was outside in accordance with the subsequent processing mode (image forming layer surface side outer winding). The wrapping humidity of the photosensitive material is 20 to 40% relative humidity (25%).
Of the resulting photothermographic material, the pH of the film surface on the image forming side is 5.0 to 5.3, and the Beck smoothness is 4600 to 4
It was 800 seconds, the pH of the opposite film surface was 5.9, and the Beck smoothness was 520 seconds.

Evaluation was performed in the same manner as in Example 1.
As shown in Table 14, the samples satisfying the conditions of the present invention showed good performance.

[0205]

[Table 14]

<Example 3> Sample N of Examples 1 and 2
o. 3 to 9, 22 to 26 (sample of the present invention), 1, 2, 1
The latex species in the lower layer of the protective layer of 0, 11, 21, 27, and 28 (samples of Comparative Examples) were compared with those of P having the same I / O value of 0.51.
ol-7, and prepared in the same manner as the coating solution for the lower layer of the protective layer in Examples 1 and 2, except that Compound D was added as a plasticizer in an amount of 15% by mass based on the solid content of the latex in order to improve the film forming property. Thereafter, a photothermographic material was prepared.

As a result of evaluation in the same manner as in Example 1, a sample satisfying the conditions of the present invention showed good performance.

<Example 4> Examples 1 to 4 were repeated except that 5.0 g of polystyrene particles having an average particle diameter of 11 µm (coefficient of variation of average particle diameter of 8%) was used as a matting agent for the coating solution for the upper protective layer.
A coating solution for the image forming layer, a coating solution for the lower protective layer and a coating solution for the upper protective layer were prepared in exactly the same manner as in Example 3, and a sample was prepared by simultaneous three-layer coating.

The drying conditions and winding appearance at the time of coating were the same as in Example 1, and the image forming layer surface side was set to the outside according to the subsequent processing mode (image forming layer surface side outer winding). The wrapping humidity of the photosensitive material was 20 to 40% relative humidity (measured at 25 ° C.), and the film surface pH on the image forming side of the obtained photothermographic material was 5.1 to 5.1.
5.3, Beck smoothness is 1300 to 1500 seconds,
The pH on the opposite side of the film surface was 5.9, and the Beck smoothness was 520 seconds.

A sample was prepared and evaluated using a latex and a compound corresponding to any of the above in the same manner as in Examples 1 to 3, and a sample satisfying the conditions of the present invention was evaluated as good in the same manner as in Example 1. Performance.

Example 5 A photothermographic material was prepared using the following support in place of the support used in Examples 1 to 4.
As a result of performing the same evaluation, a sample satisfying the conditions of the present invention showed good performance as in Examples 1 to 4.

<< Preparation of Polyethylene Terephthalate (PET) Support with Back / Undercoat Layer >> (1) Preparation of PET Support Using terephthalic acid and ethylene glycol, the intrinsic viscosity IV = 0.66 (phenol / Tetrachloroethane = 6/4 (measured at 25 ° C in mass ratio)). This was pelletized, dried at 130 ° C. for 4 hours, and then melted at 300 ° C.
After being extruded from the die, it is quenched and the film thickness after heat setting is 12
An unstretched film having a thickness of 0 μm was produced.
This is longitudinally stretched 3.3 times using rolls with different peripheral speeds.
Then, a transverse stretching was performed 4.5 times with a tenter. The temperatures at this time were 110 ° C. and 130 ° C., respectively. After that, it was heat-set at 240 ° C. for 20 seconds, and relaxed 4% in the horizontal direction at the same temperature. Then, after slitting the chuck portion of the tenter, knurling is performed on both ends, and 4.8 k
g / cm ² . Thus, the width 2.4
m, length 3500 m, thickness 120 μm, roll-shaped PE
A T support was obtained.

(2) Preparation of Undercoat Layer and Back Layer Coating liquids SA to C are prepared, and on the side where the image forming layer is formed, SC and SA are arranged in this order from the support. 8ml
/ M ² , 6.2 ml / m ² . Further, on the opposite side (back side), SA and SB in order from the support.
2 ml / m ^2, was coated with 13.8 ml / m ^2. Drying is
30 seconds at 125 ° C., 30 seconds at 150 ° C., 30 at 185 ° C.
Seconds went. 0.37 on both sides of the PET support
A corona discharge treatment of 5 kV · A · min / m ² was performed.

Coating Solution SA Latex-A 280 g KOH 0.5 g Polystyrene fine particles (average particle size: 2 μm, coefficient of variation of average particle size 7%) 0.03 g 2,4-dichloro-6-hydroxy-s-triazine 1.8 g Compound-Bc-C 0.06 g Distilled water The amount that the total amount becomes 1000 g

Coating Solution SC Pesresin A520 (30% aqueous dispersion, manufactured by Takamatsu Oil & Fats Co., Ltd.) 46 g Alkali-treated gelatin (molecular weight: about 10,000, Ca ²⁺ content: 30 ppm) 4.44 g Deionized gelatin (Ca ²⁺⁾ 0.84 g Compound-Bc-A 0.02 g Dye-Bc-A (adjusted to an optical density of 1.3 at 783 nm) Polyoxyethylene phenyl ether 1.7 g Water-soluble melamine compound (Sumitec Resin M-3, 8 mass% aqueous solution, manufactured by Sumitomo Chemical Co., Ltd.) 15 g Sb-doped SnO ₂ 20% aqueous dispersion (FS-10D, manufactured by Ishihara Sangyo Co., Ltd.) 81.5 g Polystyrene fine particles (average Particle size: 2 μm, coefficient of variation of average particle size 7%) 0.03 g Distilled water Amount that gives a total amount of 1000 g

Coating Solution SB Chemipearl S120 (27% aqueous dispersion, manufactured by Mitsui Chemicals, Inc.) 73.1 g Pesresin A615G (25% aqueous dispersion, manufactured by Takamatsu Oil & Fats Co., Ltd.) 78.9 g Compound-Bc- B 2.7 g Compound-Bc-C 0.3 g Compound-Bc-D 0.25 g Denacol EX521 (water-soluble epoxy compound, manufactured by Nagase Kasei Kogyo Co., Ltd.) 3.4 g Polymethyl methacrylate (10% aqueous dispersion, average) (Particle diameter: 5 μm, coefficient of variation of average particle: 7%)

(3) Heat treatment for transport (3-1) Heat treatment PE thus prepared with a back / undercoat layer
The T support was placed in a heat treatment zone with a total length of 200 m set at 160 ° C. and transported at a tension of 2 kg / cm ² and a transport speed of 20 m / min. (3-2) Post-heat treatment After the heat treatment, post-heat treatment was performed by passing through a zone at 40 ° C for 15 seconds, and winding was performed. The winding tension at this time was 10 kg / cm ² .

<Example 5> The photothermographic materials prepared in Examples 1 to 4 were manufactured by DRY manufactured by Fuji Photo Film Co., Ltd.
SYSTEM PROCSOR FDS-6100
When a heat development process was performed using X and the same evaluation was performed, a sample satisfying the conditions of the present invention showed good performance as in Examples 1 to 4.

[0219]

According to the present invention, fog is low and Dma
x (maximum density) is high, has good adhesion between the image forming layer and the protective layer thereon after processing, and can prevent the generation of white powder regardless of the presence or absence of light exposure before processing. It is possible to obtain a photothermographic material that is most suitable for use. In addition, water-based coating that is advantageous in terms of environment and cost is possible.

[Brief description of the drawings]

FIG. 1 is a side view showing an example of a configuration of a heat developing machine used for a heat development process of a photothermographic material according to the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 heat-developable photosensitive material 11 carry-in roller pair 12 carry-out roller pair 13 roller 14 smooth surface 15 heating heater 16 guide plate A preheating section B heat development processing section C slow cooling section

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[Procedure amendment]

[Submission date] May 21, 2002 (2005.2.
1)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H123 AB00 AB03 AB23 AB28 BA00 BA14 BA45 BA49 BA57 BB00 BB08 BB20 BB31 BB37 CB00 CB03

Claims (7)

[Claims] At least one image forming layer on a support, a lower protective layer adjacent to the image forming layer, and at least one protective layer above the lower protective layer. In the photothermographic material having an upper layer, the image forming layer contains a non-photosensitive organic silver salt, a photosensitive silver halide, a reducing agent for silver ions, and a binder, and a binder for the image forming layer. Is a polymer latex having an NH ₄ ⁺ ion content of 50 ppm or less based on the solid content, and the inorganic value based on the organic conceptual diagram of the binder in the lower layer of the protective layer is divided by the organic value. A photothermographic material, wherein the O value is larger than the I / O value of the binder in the image forming layer and smaller than the I / O value of the binder in the upper layer of the protective layer. 2. A polymer latex as a binder for the lower layer of the protective layer and the upper layer of the protective layer.
2. The photothermographic material according to item 1. 3. The image forming layer according to claim 1, wherein the image forming layer contains at least one compound which generates an imagewise chemical species capable of forming a development start point in the vicinity of a non-photosensitive organic silver salt.
2. The photothermographic material according to item 1. 4. An image forming layer having a developed silver particle density of 200 to 200 mol / mol by adding 0.01 mol / mol silver.
3. The photothermographic material according to claim 1, wherein the photothermographic material contains at least one compound that increases to 5000%. 5. An image forming layer having a covering power of 120 by adding 0.01 mol / mol of silver.
3. The photothermographic material according to claim 1, wherein the photothermographic material contains at least one compound which increases to 1000%. 6. The photothermographic material according to claim 3, further comprising a metal oxide-containing layer on at least one surface of the support. 7. An undercoat layer containing a vinylidene chloride copolymer containing at least 70% by mass of a repeating unit of a vinylidene chloride monomer on both surfaces of the support.
7. The photothermographic material according to any one of items 6.