JP2000121248A - Production of organic silver salt composition and thermal developing photosensitive material employing it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a thermal developing photosensitive material in which fog is suppressed by drying and crushing slurry or wet cake containing an organic silver salt in a high speed gas flow. SOLUTION: Hot air heated up to a preset temperature is supplied from a hot air inlet 1 using a fan. Depending on the wet conditions, slurry or wet cake containing an organic silver salt is then thrown in from a slurrylike material throwing opening 2 or a wet cake throwing opening 3 and carried by a high speed gas flow through a dry chamber 4. Subsequently, it is passed through a drying zone A, an ascending section B and a crushing/classifying section C. Dried and undried powders are then classified and only dried powder is passed through a collecting section 5, a cyclon and a bag filter thus collecting powder of the organic silver salt composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photothermographic material and, more particularly, to a method for producing an organic silver salt composition used for the photothermographic material.

[0002]

2. Description of the Related Art In recent years, in the medical field, X-ray CT, MR
As a means for outputting a diagnostic image such as I, a method has been adopted in which a photosensitive material is scanned with a laser beam and exposed to form an image. However, these photosensitive materials have been subjected to wet development processing after imagewise exposure by scanning with a laser beam and subjected to diagnosis.

In wet processing of photosensitive materials, waste liquid is a problem in terms of environmental protection. In recent years, it has been strongly desired to reduce the amount of processing waste liquid from the viewpoint of space saving.

Therefore, there has been a demand for a technique relating to a photothermographic material capable of efficiently exposing with a laser imager and forming a high-resolution and clear black image.

As this technique, for example, US Pat.
No. 152,904, No. 3,487,075 and D.C.
"Dry Silver Photographi" by Morgan
c Materials) "(Handbook of
Imaging Materials, Marcel
Dekker, Inc. 48, 1991), a photothermographic material containing an organic silver salt, photosensitive silver halide grains and a reducing agent on a support is known. Further, a heat-sensitive recording material which does not contain photosensitive silver halide grains and forms an image by thermal energy is also known.

An organic silver salt is an essential component of the photothermographic material and the thermosensitive recording material. As a method for producing an organic silver salt, a water-soluble silver salt is added to an alkali salt of an organic acid to form an aqueous organic acid silver salt dispersion, desalting of by-produced salts is performed, and then drying is performed. A method for obtaining a powdery organic silver salt is known. Since the organic silver salt used in the photothermographic material is thermally sensitive, a drying method such as hot air drying or vacuum drying at a relatively low temperature is usually used. However, in the heat-developable photographic light-sensitive material using the organic acid silver salt formed by these methods, there is a problem in photographic performance due to deterioration of image storability and an increase in the density of a white background of the formed image. . In addition, there are also problems in productivity, such as loss of adhesion of the organic silver salt to the dryer during drying and a decrease in drying ability due to the inability to apply high heat.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a heat-developable photographic material having low fog, and to provide a novel method for producing an organic silver salt having high productivity.

[0008]

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

1. A method for producing an organic silver salt composition, comprising drying and / or pulverizing a slurry or a wet cake containing an organic silver salt in a high-speed air stream.

[0010] 2. 2. The method for producing an organic silver composition according to claim 1, wherein the high-speed airflow is a swirling flow.

3. A method for producing an organic silver salt composition, comprising drying and / or pulverizing a slurry or a wet cake containing an organic silver salt in swirling hot air.

4. A method for producing an organic silver salt composition, comprising drying and / or pulverizing a slurry or a wet cake containing an organic silver salt in a cylindrical device.

5. The method for producing an organic silver salt composition according to any one of items 1 to 4, wherein the drying and / or grinding is performed for 7 seconds or less.

6. The method for producing an organic silver salt composition according to any one of claims 1 to 5, wherein the water content is 10% or less.

[0015] 7. An organic silver salt composition having a water content of 10% or less.

8. 8. A photothermographic material comprising the organic silver salt composition as described in 7 above.

9. A photothermographic material comprising an organic silver salt composition produced by the production method according to any one of the above items 1 to 6.

Hereinafter, the present invention will be described in detail.

In the present invention, "slurry" means a fluid and wet state, and "wet cake" means a wet but non-flowable state.

As a general method for producing an organic silver salt, first, an organic acid alkali salt is formed by a reaction between an organic acid and an alkali in an aqueous medium, and then an aqueous organic silver salt is formed by a reaction with a water-soluble silver salt in the same solvent. A silver salt is formed. Water is added to the formed aqueous organic silver salt to remove by-produced salt, and this is repeated several times to obtain a slurry or wet cake of the organic silver salt.

The thus obtained organic silver salt in the form of a slurry or wet cake is dried in order to further remove water, and then pulverized to obtain a powdery solid of the organic silver salt.

In the present invention, the slurry or wet cake containing the organic silver salt is dried and / or pulverized in a high-speed air stream. The air velocity is 2.0 Nm ³ /
min or more, more preferably 5.0 Nm ³ / min or more, and further preferably 8.0 Nm ³ / min or more.

In the present invention, the slurry or wet cake containing the organic silver salt is preferably dried and / or pulverized in a swirling hot air. The hot air temperature is preferably 20 ° C or higher, more preferably 40 ° C or higher,
Further, the temperature is preferably 60 ° C or higher.

In the present invention, the high-speed airflow is preferably a swirling flow.

In the present invention, it is preferable to carry out drying and / or pulverization in a cylindrical device.

The cylindrical shape may be a straight pipe or an L-shape, and may be a U-shape or a donut shape.

In the present invention, the time required for drying and / or grinding is preferably 7 seconds or less. The time is more preferably 3 seconds or less, and further preferably 1.5 seconds or less.

In the present invention, the water content of the organic silver salt composition obtained by drying and / or pulverizing a slurry or a wet cake containing the organic silver salt is preferably 10% or less. It is more preferably at most 5%, further preferably at most 1%. As a method of measuring the water content of the organic silver salt composition, a method of observing a change in weight with a moisture meter or the like can be mentioned.

One example of a high-speed instantaneous flash dryer for drying and / or pulverizing in a high-speed airflow used in the present invention will be described with reference to FIG.

In the figure, 1 is a hot air inlet, 2 is a slurry-like material inlet, and 3 is a wet cake inlet. The hot air heated to a preset temperature is sent from the hot air inlet 1 using a fan (not shown). A slurry or a wet cake containing an organic silver salt may have a wet state depending on its wet state.
, Or through the wet cake inlet 3, and is transported in the drying chamber 4 by a high-speed airflow, passes through the drying zone A, passes through the ascending section B, passes through the pulverizing and classifying section C. The dried and undried powders are classified, and only the dried ones pass through a collecting unit 5 and pass through a cyclone and a bag filter (not shown) to collect the powder of the organic silver salt composition.

A specific apparatus meeting the object of the present invention is a flash jet dryer manufactured by Seishin Corporation.

The organic silver salt composition in the present invention may be the organic silver salt itself, or may contain silver halide grains and other additives for a photothermographic material.

According to the drying method of the present invention, it has become possible to easily provide a dry powder of an organic silver salt composition which does not cause damage such as fog at a low temperature in a short time. Further, the organic acid silver salt powder thus obtained had good redispersibility even in the subsequent preparation of a coating solution for the photosensitive material.

The silver halide grains used in the present invention function as an optical sensor. In the present invention, the average particle size is preferably 0.1 μm or less, more preferably 0.01 μm to 0.1 μm, particularly preferably 0.01 μm to 0.1 μm, in order to suppress white turbidity after image formation and obtain good image quality. It is 0.02 μm to 0.08 μm.

The term "grain size" as used herein refers to the length of a ridge of a silver halide grain when the silver halide grain is a cubic or octahedral so-called normal crystal. In the case of non-normal crystals, for example, in the case of spherical, rod-shaped, or tabular grains, the diameter of a sphere equivalent to the volume of silver halide grains is indicated. Further, the silver halide is preferably monodispersed.

The term "monodispersion" as used herein means a case where the degree of monodispersion determined by the following equation is 40% or less. In the present invention, the monodispersity is more preferably 30% or less, particularly preferably 0.1% or more and 20% or less.

Monodispersity = (standard deviation of particle size) / (average value of particle size) × 100 In the present invention, the silver halide particles have an average particle size of 0.1.
μm or less and more preferably monodisperse particles,
By setting it in this range, the granularity of the image is also improved.

The shape of the silver halide grains is not particularly limited, but it is preferable that the ratio occupied by the Miller index [100] plane is high, and this ratio is 50% or more, and more preferably 7%.
It is preferably at least 0%, particularly preferably at least 80%. The ratio of the Miller index [100] plane is determined by the T.M. Tani, J .; Imaging Sci. , 29,
165 (1985).

Another preferred form of silver halide is tabular grains. The term "tabular grain" as used herein means that the thickness in the vertical direction is h.mu.
When m, the aspect ratio = r / h means 3 or more. Among them, the aspect ratio is more preferably 3 or more and 50 or less. The particle size is preferably 0.1 μm or less, more preferably 0.01 μm to 0.08 μm. These are described in U.S. Patent Nos. 5,264,337, 5,314,798, and 5,320,958, and the like. Can be.

When these tabular grains are used in the present invention, the sharpness of an image is further improved. The halogen composition is not particularly limited, and may be any of silver chloride, silver chlorobromide, silver chloroiodobromide, silver bromide, silver iodobromide, and silver iodide. AgX particles used in the present invention are P.A. Glafk
Chimie et Physique P
photographique (Paul Montel)
G., 1967); F. Duffin's Pho
graphical Emulsion Chemis
try (published by The Focal Press, 1966)
Year), V. L. Mak by Zelikman et al
ing and Coating Photograph
hic Emulsion (The Focal Pr
ess, 1964) and the like, and can be prepared using an Ag emulsion prepared by a method described in US Pat.

The silver halide used in the present invention is preferably contained in an amount of 0.75 to 30% by weight based on the organic silver salt.

The silver halide used in the present invention preferably contains metal ions belonging to groups 6 to 11 of the periodic table. As the above metals, W, Fe, Co,
Ni, Cu, Ru, Rh, Pd, Re, Os, Ir, P
t and Au are preferred.

These metal ions can be introduced into silver halide in the form of a metal complex or a metal complex ion. As these metal complexes or metal complex ions, hexacoordinate metal complexes represented by the following general formula are preferable.

In the general formula [ML ₆ ] ^m , M is a transition metal selected from elements of Groups 6 to 11 of the periodic table, L is a ligand, and m is 0,-, 2-, 3- or 4-
Represents Specific examples of the ligand represented by L include halides (fluoride, chloride, bromide and iodide), cyanide, cyanate, thiocyanate, selenocyanate, tellurocyanate, azide and aquo. Ligand, nitrosyl, thionitrosyl and the like, preferably aquo, nitrosyl and thionitrosyl. If an aquo ligand is present, it preferably occupies one or two of the ligands. L may be the same or different.

Particularly preferred examples of M are rhodium (Rh), ruthenium (Ru), rhenium (Re), iridium (Ir) and osmium (Os).

Specific examples of transition metal complex ions are shown below, but the present invention is not limited to these.

[0047] 1: [RhCl _6] ^3- 2: [RuCl _6] ^3- 3: [ReCl _6] ^3- 4: [RuBr _6] ^3- 5: [OsCl _6] ^3- 6: [IrCl _6] ^{4 -} 7: [Ru (NO) Cl _5] ^2- 8: [RuBr ₄ (H ₂ O)] ^2- 9: _{[Ru (NO) (H 2 O} ) Cl 4 ] ^- 10: [RhCl ₅ (H ₂ O)] ^2- 11: [Re (NO) Cl _5] ^2- 12: [Re (NO) CN _5] ^2- 13: [Re (NO) ClCN _4] ^2- 14: [Rh (NO) ₂ Cl _4] ^- 15: _{[Rh (NO) (H 2 O} ) Cl 4 ] ^- 16: [Ru (NO) CN _5] ^2- 17: [Fe (CN) _6] ^3- 18: [Rh (NS) Cl _5] ^2- 19: [Os (NO) Cl _5] ^2- 20: [Cr (NO) Cl _5] ^2- 21: [Re (NO) Cl _5] ^- 22: [Os (NS) Cl ₄ (TeCN )] ^2-23 : [ Ru (NS) Cl _5] ^2- 24: _{[Re (NS) Cl 4 (SeCN} ) ] ^2- 25: [Os (NS) Cl (SCN) 4 ] ^2- 26: [Ir (NO) Cl _5] ^{2 -} 27: [Ir (NS) Cl _5] ^2- these metal ions may be a metal complex or metal complex ions one type, the metal of the same kind of metal or different may be used alone or in combination. The content of these metal ions, metal complexes or metal complex ions, generally is suitably 1 × 10 ^-9 ~1 × 10 ^-2 mol per mol of silver halide, preferably 1 × 10 ^{- It is 8} to 1 × 10 ^-4 mol.

The compounds providing these metals are preferably added during silver halide grain formation and incorporated into silver halide grains. Preparation of silver halide grains, that is, nucleation, growth, physical ripening, and chemical ripening Although it may be added at any stage before and after sensitization, it is particularly preferable to add at the stage of nucleation, growth and physical ripening, more preferably at the stage of nucleation and growth, and most preferably. It is added at the stage of nucleation.

In addition, the compound may be added in several divided portions, may be added uniformly in the silver halide grains, or may be added to silver halide grains.
-306236, 3-167545, 4-76
No. 534, No. 6-110146, No. 5-273683
As described in Japanese Patent Application Laid-Open No. H10-284, etc., the particles can be contained in the particles with a distribution. Preferably, a distribution can be provided inside the particles.

These metal compounds can be added by dissolving in water or a suitable organic solvent (eg, alcohols, ethers, glycols, ketones, esters, amides). A method in which an aqueous solution of a powder or an aqueous solution in which a metal compound and NaCl and KCl are dissolved together is added to a water-soluble silver salt solution or a water-soluble halide solution during grain formation, or a silver salt solution and a halide solution are used. When they are mixed simultaneously, they are added as a third aqueous solution to prepare silver halide grains by a three-liquid simultaneous mixing method, a method in which a required amount of an aqueous solution of a metal compound is charged into a reaction vessel during grain formation, or a method in which halogen is added. There is a method in which another silver halide grain doped with metal ions or complex ions in advance during the preparation of silver halide is added and dissolved. In particular, a method of adding an aqueous solution of a powder of a metal compound or an aqueous solution in which a metal compound and NaCl and KCl are dissolved together is added to a water-soluble halide solution.

When adding to the particle surface, a necessary amount of an aqueous solution of a metal compound can be charged into the reaction vessel immediately after the formation of the particles, during or during the physical ripening, or at the time of chemical ripening.

The silver halide grains used in the present invention may or may not be desalted after grain formation. When desalting is performed, methods known in the art such as a noodle method and a flocculation method are used. Can be desalted by washing with water.

The silver halide grains used in the present invention are preferably chemically sensitized. Preferred chemical sensitization methods are sulfur sensitization, as is well known in the art,
Selenium sensitization and tellurium sensitization can be used. Further, a noble metal sensitization method or a reduction sensitization method of a gold compound, platinum, palladium, an iridium compound or the like can be used. As the compound preferably used in the sulfur sensitization method, the selenium sensitization method, and the tellurium sensitization method, known compounds can be used, and the compounds described in JP-A-7-128768 can be used. Examples of tellurium sensitizers include diacyl tellurides, bis (oxycarbonyl) tellurides,
Bis (carbamoyl) tellurides, diacyl tellurides, bis (oxycarbonyl) ditellurides, bis (carbamoyl) ditellurides, compounds having a P = Te bond, tellurocarboxylates, Te-organyltellurocarboxylates, Use of (poly) tellurides, tellurides, tellurols, telluroacetals, tellurosulfonates, compounds having a P-Te bond, Te-containing heterocycles, tellurocarbonyl compounds, inorganic tellurium compounds, colloidal tellurium, etc. Can be. Compounds preferably used for the noble metal sensitization method include, for example, chloroauric acid, potassium chloroaurate, potassium aurithiocyanate, gold sulfide, gold selenide, US Pat. No. 2,448,060, British Patent No. 618,061 and the like. Can be preferably used.

Specific compounds for the reduction sensitization method include, for example, stannous chloride, aminoiminomethanesulfinic acid, hydrazine derivatives, borane compounds, silane compounds, polyamine compounds and the like in addition to ascorbic acid and thiourea dioxide. be able to. Further, reduction sensitization can be achieved by ripening the emulsion while maintaining the pH of the emulsion at 7 or more or the pAg at 8.3 or less. Further, reduction sensitization can be achieved by introducing a single addition portion of silver ion during grain formation.

The organic acid silver salt formed by the method of the present invention is a reducible silver source and is an organic acid containing a reducible silver ion source. Examples of the organic acid used in the present invention include an aliphatic carboxylic acid, a carbocyclic carboxylic acid, a heterocyclic carboxylic acid, a heterocyclic compound and the like, and particularly a long chain (10 to 30, preferably 15 to 25 (Carbon atoms) aliphatic carboxylic acids and heterocyclic carboxylic acids having a nitrogen-containing heterocyclic ring are preferably used. Further, when the ligand is 4.
Organic silver salt complexes having a total stability constant for silver ions of 0 to 10.0 are also useful.

Examples of the silver salt of an organic acid used in the present invention include Research Disclosure No. 170.
And silver salts of fatty acids (eg, silver salts of gallic acid, oxalic acid, behenic acid, arachidic acid, stearic acid, palmitic acid, lauric acid, etc.); Carboxyalkylthiourea salts (eg, 1- (3-carboxypropyl) thiourea, 1- (3-carboxypropyl) -3,3-dimethylthiourea); polymerization reaction products of aldehydes and hydroxy-substituted aromatic carboxylic acids (E.g., aldehydes (formaldehyde, acetaldehyde, butyraldehyde, etc.) and hydroxy-substituted aromatic carboxylic acids (e.g., salicylic acid, benzoic acid, 3,5-dihydroxybenzoic acid, 5,5-thiodisalicylic acid, etc.) Silver complex or the like of a polymerization reaction product of), a silver salt or complex of a thione (for example, 3- (2-carbo) (Silethyl) -4-hydroxymethyl-4-thiazoline-2-thione and 3-carboxymethyl-4-thiazoline-2-thione), imidazole, pyrazole, urazole, 1,2,4-thiazole and 1H-tetrazole, Complexes or salts of nitrogen acids and silver selected from -amino-5-benzylthio-1,2,4-triazole and benzotriazole; silver salts such as saccharin and 5-chlorosalicylaldoxime; and silver salts of mercaptides . Among the organic silver salts described above,
Silver salts of fatty acids are preferably used, and silver behenate, silver arachidate and silver stearate are more preferably used.

The dispersion of the aqueous organic silver salt used in the present invention can be obtained by mixing silver nitrate and an organic acid alkali metal salt. When the organic silver salt is formed, silver nitrate and silver halide are simultaneously added and mixed. It is preferably produced using a mixing method.

For example, an organic acid alkali metal salt soap (eg, sodium behenate, sodium arachidate, etc.) is prepared by adding an alkali metal hydroxide (eg, sodium hydroxide, potassium hydroxide, etc.) to an organic acid. By using a control double jet method, silver nitrate and silver halide can be simultaneously added and mixed to prepare an aqueous organic silver salt dispersion used in the present invention.

Further, the aqueous organic silver salt dispersion used in the present invention can be prepared by a so-called control triple jet method in which an alkali metal salt of an organic acid, silver nitrate and silver halide are simultaneously added and mixed, respectively. .

In the present invention, from the viewpoint of simplicity in the production process, the method for producing an aqueous organic silver salt dispersion using the above-described controlled double jet method is preferably used. From the viewpoint of producing a high-sensitivity photothermographic material, the method for producing an aqueous organic silver salt dispersion using the above-described control triple jet method is preferably used.

In the method for producing a photothermographic material of the present invention, an organic silver salt dispersion containing photosensitive silver halide particles is taken out of the aqueous organic silver salt dispersion as obtained above as a solid such as a powder. Then, the mixture is dispersed together with a binder and a solvent to prepare a photosensitive emulsion.

The photothermographic material of the present invention preferably contains a reducing agent. Examples of suitable reducing agents are described in U.S. Patent Nos. 3,770,448, 3,773,512,
No. 3,593,863 and Research D
No. 17029 and 29996, and include the following: Aminohydroxycycloalkenonone compounds (eg, 2-hydroxypiperidino-2-cyclohexenone); aminoreductones esters (eg, piperidinohexose reductone monoacetate) as precursors of reducing agents; N- Hydroxyurea derivatives (e.g., Np-methylphenyl-N-hydroxyurea); hydrazones of aldehydes or ketones (e.g., anthracenaldehyde phenylhydrazone); phosphoramidophenols; phosphoramidoanilines; polyhydroxybenzenes (Eg, hydroquinone, t-butyl-hydroquinone, isopropylhydroquinone, and (2,5-dihydroxy-phenyl) methylsulfone); sulfhydroxamic acids (eg, benzenesulfhydroxam) ); Sulfonamides anilines (e.g., 4-(N-
Methanesulfonamido) aniline); 2-tetrazolylthiohydroquinones (for example, 2-methyl-5- (1-
Phenyl-5-tetrazolylthio) hydroquinone); tetrahydroquinoxalines (e.g., 1,2,3,4-
Amidooxins; Azines (for example, a combination of an aliphatic carboxylic acid arylhydrazide and ascorbic acid); a combination of polyhydroxybenzene and hydroxylamine, reductone and / or hydrazine; Hydroxamic acids; Azines and sulfone Combinations of amidophenols; α-cyanophenylacetic acid derivatives; bis-β-naphthol and 1,3
5-pyrazolones; sulfonamidophenol reducing agents; 2-phenylindane-1,3-dione and the like; chromans;
Dihydropyridines (for example, 2,6-dimethoxy-
3,5-dicarbethoxy-1,4-dihydropyridine); bisphenols (for example, bis (2-hydroxy-3-t-butyl-5-methylphenyl) methane, bis (6-hydroxy-m-tri) mesitol (Mesi
tol), 2,2-bis (4-hydroxy-3-methylphenyl) propane, 4,5-ethylidene-bis (2-
t-butyl-6-methyl) phenol), ultraviolet-sensitive ascorbic acid derivatives and 3-pyrazolidones. Among them, particularly preferred reducing agents are hindered phenols.
Examples of the hindered phenols include compounds represented by the following general formula (A).

[0063]

Embedded image

In the formula, R is a hydrogen atom or a group having 1 carbon atom.
To 10 alkyl groups (for example, butyl group, 2,4,4-
R ′ and R ″ represent an alkyl group having 1 to 5 carbon atoms (eg, a methyl group, an ethyl group, a t-butyl group, etc.).

Specific examples of the compound represented by formula (A) are shown below. However, the present invention is not limited to these.

[0066]

Embedded image

[0067]

Embedded image

The amount of the reducing agent including the compound represented by formula (A) is preferably 1 × 1 per mol of silver.
It is from 0 ^-2 to 10 mol, especially from 1 x 10 ^{-2 to} 1.5 mol.

The photothermographic material of the present invention may contain an antifoggant. What is known as the most effective antifoggant is mercury ion. The use of a mercury compound as an antifoggant in a light-sensitive material is disclosed in, for example, US Pat. No. 3,589,903. However, mercury compounds are environmentally unfriendly. Non-mercury antifoggants include, for example, US Pat.
No. 075 and 4,452,885 and JP-A-59
Preferred are antifoggants such as those disclosed in US Pat.

Particularly preferred non-mercury antifoggants are US Pat. Nos. 3,874,946 and 4,756,99.
No.9, -C (X ₁ )
(X ₂ ) (X ₃ ) (where X ₁ and X ₂ represent a halogen atom, and X ₃ represents a hydrogen atom or a halogen atom) and is a heterocyclic compound provided with one or more substituents. As examples of suitable antifoggants, compounds described in paragraphs [0030] to [0036] of JP-A-9-288328 are preferably used.

As another example of the preferred antifoggant, JP-A-9-90550, paragraph [006]
2] to [0063]. Still other suitable antifoggants are described in U.S. Pat.
8,523 and British Patent Application No. 9300147.7.
No. 9311790.1.

The photothermographic material of the present invention preferably contains a toning agent for the purpose of improving the silver tone after development. Examples of suitable toning agents are Research Discl
No. 17029, which includes the following:

Imides (eg, phthalimide); cyclic imides, pyrazolin-5-ones, and quinazolinones (eg, succinimide, 3-phenyl-2-pyrazolin-5-one, 1-phenylurazole, quinazoline and , 4-thiazolidinedione); naphthalimides (eg, N-hydroxy-1,8-naphthalimide); cobalt complexes (eg, hexamine trifluoroacetate of cobalt), mercaptans (eg, 3
-Mercapto-1,2,4-triazole); N- (aminomethyl) aryldicarboximides (for example,
N- (dimethylaminomethyl) phthalimide); blocked pyrazoles, isothiuronium (isoth
uronium) derivatives and certain photobleaching combinations (eg, N, N'-hexamethylene (1-carbamoyl-3,5-dimethylpyrazole), 1,8-
A combination of (3,6-dioxaoctane) bis (isothiuronium trifluoroacetate) and 2- (tribromomethylsulfonyl) benzothiazole; a merocyanine dye (e.g., 3-ethyl-5-((3-ethyl -2-benzothiazolinylidene (benzothiazolinylidene))-1-methylethylidene) -2-thio-2,4
Oxazolidinedione); phthalazinone, a phthalazinone derivative or a metal salt of these derivatives (for example, 4-
(1-naphthyl) phthalazinone, 6-chlorophthalazinone, 5,7-dimethyloxyphthalazinone, and 2,3
-Dihydro-1,4-phthalazinedione); a combination of phthalazinone and a sulfinic acid derivative (for example, 6-chlorophthalazinone + sodium benzenesulfinate or 8-methylphthalazinone + sodium p-trisulfonate); phthalazine + phthalate Combinations of acids; phthalazine (including adducts of phthalazine) and maleic anhydride, and phthalic acid, 2,3-naphthalenedicarboxylic acid or o-phenylene acid derivatives and anhydrides thereof (for example,
Combination with at least one compound selected from phthalic acid, 4-methylphthalic acid, 4-nitrophthalic acid and tetrachlorophthalic anhydride; quinazolinediones, benzoxazine, naloxazine derivatives; benzoxazine-2,4-dione (Eg, 1,3-benzoxazine-2,4-dione); pyrimidines and asymmetric-triazines (eg, 2,4-dihydroxypyrimidine), and tetraazapentalene derivatives (eg,
3,6-dimercapto-1,4-diphenyl-1H, 4
H-2,3a, 5,6a-tetraazapentalene). Preferred toning agents are phthalazone or phthalazine.

The photothermographic materials of the present invention include, for example, JP-A-63-159814, JP-A-60-140335, JP-A-63-231437, JP-A-63-259651 and JP-A-6-259561.
3-304242, 63-15245, U.S. Pat. Nos. 4,639,414 and 4,740,455,
Nos. 4,741,966 and 4,751,175
No. 4,835,096.

Useful sensitizing dyes for use in the present invention include, for example, Research Disclosure Item
17643 IV-A (p. 23, December 1978) and Item 1831X (p. 437, August 1978). In particular, a sensitizing dye having a spectral sensitivity suitable for the spectral characteristics of various scanner light sources can be advantageously selected. For example, JP-A-9-34078, JP-A-9-54409, and JP-A-9-806
The compounds described in No. 79 are preferably used.

In the present invention, a mercapto compound, a disulfide compound, and a thione compound are contained in order to control development by suppressing or accelerating development, to improve spectral sensitization efficiency, and to improve storage stability before and after development. be able to.

When a mercapto compound is used in the present invention, it may be of any structure,
Those represented by -SS-Ar are preferred. In the formula, M is a hydrogen atom or an alkali metal atom, and Ar represents an aromatic ring or a condensed aromatic ring having one or more nitrogen, sulfur, oxygen, selenium or tellurium atoms.

As the aromatic ring, an aromatic carbon ring and a heteroaromatic ring are used. In the present invention, a heteroaromatic ring is preferably used. As the heteroaromatic ring, for example, benzimidazole, naphthymidazole, benzothiazole, naphthothiazole, benzoxazole, naphthoxazole, benzoselenazole, benzotellurazole, imidazole, oxazole, pyrazole, triazole, thiadiazole, tetrazole, triazine, pyrimidine, Pyridazine, pyrazine, pyridine, purine, quinoline or quinazolinone. The heteroaromatic ring includes, for example, a halogen atom (eg, Br and Cl), a hydroxy group, an amino group, a carboxy group, an alkyl group (eg, one or more carbon atoms, preferably
Having a substituent selected from the group consisting of those having from 1 to 4 carbon atoms) and alkoxy groups (e.g., having at least one carbon atom, preferably having from 1 to 4 carbon atoms). Is also good. Examples of the mercapto-substituted heteroaromatic compound include 2-mercaptobenzimidazole and 2-mercaptobenzimidazole.
Mercaptobenzoxazole, 2-mercaptobenzothiazole, 2-mercapto-5-methylbenzothiazole, 3-mercapto-1,2,4-triazole,
-Mercaptoquinoline, 8-mercaptopurine, 2,
3,5,6-tetrachloro-4-pyridinethiol,
-Hydroxy-2-mercaptopyrimidine, 2-mercapto-4-phenyloxazole and the like,
The present invention is not limited to these.

In the present invention, a matting agent is preferably contained on the photosensitive layer side, and a matting agent is preferably provided on the surface of the photosensitive material in order to prevent the image after thermal development from being damaged. It is preferable that the content of the agent is 0.5 to 30% by weight based on all binders on the emulsion layer side.

The material of the matting agent used in the present invention may be either an organic substance or an inorganic substance.

For example, as the inorganic substance, Swiss Patent No. 3
Silica described in No. 30,158, French Patent No. 1,29
No. 6,995, etc., British Patent No. 1,17
Alkaline earth metals or carbonates such as cadmium and zinc described in 3,181 and the like can be used as a matting agent. As organic substances, US Pat. No. 2,322,03
7, starch derivatives described in Belgian Patent No. 625,451 and British Patent No. 981,198, polyvinyl alcohol described in Japanese Patent Publication No. 44-3643, and Swiss Patent No. 330,158. Polystyrene or polymethacrylate described in U.S. Pat.
Organic matting agents such as polyacrylonitrile described in No. 79,257 and polycarbonate described in U.S. Pat. No. 3,022,169 can be used.

The shape of the matting agent may be either regular or irregular, but is preferably regular and spherical. The size of the matting agent is represented by a diameter when the volume of the matting agent is converted into a sphere. In the present invention, the particle diameter of the matting agent indicates the diameter converted into a sphere.

The matting agent used in the present invention preferably has an average particle size of 0.5 μm to 10 μm, more preferably 1.0 μm to 8.0 μm. The matting agent has a coefficient of variation of the particle size distribution of preferably 50% or less, more preferably 40% or less, and particularly preferably 30% or less.

Here, the variation coefficient of the particle size distribution is a value represented by the following equation.

(Standard deviation of particle size) / (average value of particle size) × 100 The matting agent used in the present invention can be contained in any constituent layer, but in order to achieve the object of the present invention, It is preferably a constituent layer other than the photosensitive layer, and more preferably the outermost layer as viewed from the support.

The method of adding the matting agent used in the present invention may be a method of dispersing in a coating solution in advance and applying the same, or spraying the matting agent after application of the coating solution and before drying is completed. May be used. When a plurality of types of matting agents are added, both methods may be used in combination.

In the present invention, a conductive compound such as a metal oxide and / or a conductive polymer can be contained in the constituent layer in order to improve the chargeability. These may be contained in any layer, but are preferably contained in an undercoat layer, a backing layer, a layer between the photosensitive layer and the undercoat, and the like.

In the present invention, US Pat.
The conductive compounds described in No. 773 columns 14 to 20 are preferably used.

Various additives may be added to any of the photosensitive layer, the non-photosensitive layer, and other constituent layers. In the photothermographic material of the present invention, for example, a surfactant, an antioxidant, a stabilizer, a plasticizer, an ultraviolet absorber, a coating aid, and the like may be used in addition to the above. These additives and the other additives mentioned above are used in Research Disclosure.
re Item 17029 (June 1978, p. 9-
The compound described in 15) can be preferably used.

Binders suitable for the photothermographic material of the present invention are transparent or translucent, generally colorless, and include natural polymer synthetic resins, polymers and copolymers, and other film-forming media such as gelatin, gum arabic,
Poly (vinyl alcohol), hydroxyethyl cellulose, cellulose acetate, cellulose acetate butyrate, poly (vinyl pyrrolidone), casein, starch, poly (acrylic acid), poly (methyl methacrylic acid), poly (vinyl chloride), poly (methacrylic acid) ), Copoly (styrene-maleic anhydride), copoly (styrene-acrylonitrile), copoly (styrene-butadiene), poly (vinyl acetal) s (eg, poly (vinyl formal) and poly (vinyl butyral)), poly (ester) ), Poly (urethane), phenoxy resin, poly (vinylidene chloride), poly (epoxide),
Poly (carbonate) s, poly (vinyl acetate),
There are cellulose esters and poly (amides). It may be hydrophilic or non-hydrophilic. In order to protect the surface of the light-sensitive material and prevent abrasion, a non-light-sensitive layer may be provided outside the light-sensitive layer. The binder used for these non-photosensitive layers may be the same as or different from the binder used for the photosensitive layers.

In the present invention, in order to increase the speed of thermal development, the amount of the binder in the photosensitive layer is 1.5 to 10 g / m ^2.
It is preferred that More preferably, 1.7 to 8 g
/ M ² .

The support used in the present invention may be a plastic film (for example, polyethylene terephthalate, polycarbonate, or the like) in order to prevent deformation of an image after development processing.
Polyimide, nylon, cellulose triacetate, polyethylene naphthalate) are preferred.

Among them, a preferred support is a support made of polyethylene terephthalate (hereinafter abbreviated as PET) and a plastic (hereinafter abbreviated as SPS) containing a styrene polymer having a syndiotactic structure. The thickness of the support is about 50 to 300 μm, preferably 70 to 180 μm.

Further, a heat-treated plastic support may be used. The plastics to be employed include the above-mentioned plastics. The heat treatment of the support means that after forming these supports and before the photosensitive layer is applied, at a temperature higher than the glass transition point of the support by 30 ° C. or more,
Preferably at a temperature higher than 35 ° C., more preferably 40 ° C.
It is preferable to heat at a temperature higher than ℃. However, the effect of the present invention cannot be obtained by heating at a temperature exceeding the melting point of the support.

Next, the plastic used will be described.

PET is a polyester in which all of the polyester components are made of polyethylene terephthalate. In addition to polyethylene terephthalate, terephthalic acid, naphthalene-2,6-dicarboxylic acid, isophthalic acid, butylene dicarboxylic acid, and 5-sodium sulfo acid are used as acid components. A polyester containing a modified polyester component of isophthalic acid, adipic acid or the like and a glycol component such as ethylene glycol, propylene glycol, butanediol, cyclohexanedimethanol or the like in an amount of 10 mol% or less of the entire polyester may be used.

SPS is a polystyrene having steric regularity unlike ordinary polystyrene (atactic polystyrene). The regular stereoregular structure part of SPS is called a racemo chain, and it is preferable that there are more regular parts such as two, three, five or more. In the present invention, the racemo chain is 2 It is preferably 85% or more in the chain, 75% or more in the three chains, 50% or more in the five chains, and 30% or more in the further chains. The polymerization of SPS can be carried out according to the method described in JP-A-3-131843.

For the method of forming a support and the method of producing an undercoat used in the present invention, known methods can be used. Preferably, the method described in paragraph [0030] of JP-A-9-50094 is used.
To [0070].

The photothermographic material of the present invention, which forms a photographic image by heat development, comprises a reducible silver source (organic silver salt), a photosensitive silver halide, a reducing agent and, if necessary, silver. It is preferable that the photothermographic material contains a color toning agent which suppresses the color tone of the present invention in a state of being usually dispersed in an (organic) binder matrix. The photothermographic material of the present invention is stable at room temperature, but is exposed to a high temperature (for example, 80 ° C. to 14 ° C.).
(0 ° C.). Heating generates silver through an oxidation-reduction reaction between an organic silver salt (functioning as an oxidizing agent) and a reducing agent. This oxidation-reduction reaction is accelerated by the catalytic action of the latent image generated on the silver halide upon exposure. The silver formed by the reaction of the organic silver salt in the exposed areas provides a black image, which contrasts with the unexposed areas, resulting in the formation of an image. This reaction process proceeds without supplying a processing liquid such as water from the outside.

The photothermographic material of the present invention has at least one photosensitive layer on a support. Although only a photosensitive layer may be formed on the support, it is preferable to form at least one non-photosensitive layer on the photosensitive layer. To control the amount or wavelength distribution of light passing through the photosensitive layer, a filter dye layer on the same side as the photosensitive layer and / or an antihalation dye layer, a so-called backing layer, may be formed on the opposite side. A dye or pigment may be included in the active layer. As the dye to be used, any compound may be used as long as it has a desired absorption in a desired wavelength range, and examples thereof include JP-A-59-6481 and JP-A-59-1.
No. 82436, U.S. Pat. Nos. 4,271,263 and 4,594,312, European Patent Publication 533,008.
No. 652,473, JP-A-2-216140,
4-348339, 7-191432, 7-
Compounds described in, for example, No. 301890 are preferably used.

These non-photosensitive layers preferably contain the above-mentioned binder and matting agent, and may further contain a slip agent such as a polysiloxane compound, wax and liquid paraffin.

The photosensitive layer may be composed of a plurality of layers, and the sensitivity may be changed to a high-sensitive layer / low-sensitive layer or a low-sensitive layer / high-sensitive layer in order to adjust the gradation.

The details of the photothermographic material are described in, for example, US Pat. Nos. 3,152,904 and 3,457,
No. 075, and D.A. “Dry Silver Photographic Materials (Dry Silver P) by Morgan
photographic Material) ”and D.C.
Morgan and B.A. Shelley
y) "Heat treated silver system (The
rmally Processed SilverSy
stems) "(Imaging Processes and Materials)
s and Materials) Neblette
Eighth Edition, Sturge, V.S. Walworth, A .; Shepp
Editing, 2nd page, 1969). Among them, the present invention is characterized in that an image is formed by thermally developing a photosensitive material at 80 to 140 ° C., and no fixing is performed. Therefore, the silver halide and the organic silver salt remaining in the unexposed area remain in the photosensitive material without being removed.

In the present invention, after the heat development processing,
The optical transmission density of the light-sensitive material containing the support at 400 nm is preferably 0.2 or less. A more preferable value of the optical transmission density is 0.02 or more and 0.2 or less.

[0105]

EXAMPLES The present invention will be described below in detail with reference to examples, but embodiments of the present invention are not limited thereto.

Example 1 (Preparation of Silver Halide Emulsion A) 7.5 g of ossein gelatin and 10 mg of potassium bromide were dissolved in 900 ml of water, and the temperature was adjusted to 35 ° C. and the pH to 3.0.
g of an aqueous solution containing potassium bromide and potassium iodide in a molar ratio of (98/2) (equimolar to silver nitrate) and K ₂ [Ir (NO) Cl ₅ ] salt in an amount of 1 mol / mol of silver. × 10 ^-4 mol was added over 10 minutes by the controlled double jet method while maintaining the pAg at 7.7.
Thereafter, 4-hydroxy-6-methyl-1,3,3a, 7
-Tetrazaindene was added and the pH was adjusted to 5 with NaOH to obtain cubic silver iodobromide grains having an average grain size of 0.06 µm, a grain size variation coefficient of 11%, and a [100] face ratio of 87%. This emulsion was subjected to coagulation sedimentation using a gelatin coagulant and desalting treatment.
1 g was added to adjust the pH to 5.9 and the pAg to 7.5. Further, it was optimally subjected to chemical sensitization with sodium thiosulfate and chloroauric acid to obtain a silver halide emulsion A.

(Preparation of Organic Fatty Acid Na Solution) 945 ml
32.4 g of behenic acid, 9.9 g of arachidic acid in pure water of
5.6 g of stearic acid was dissolved at 90 ° C. Next, while stirring at a high speed, 98 m of 1.5 M aqueous sodium hydroxide solution
1 was added. Next, after adding 0.93 ml of concentrated nitric acid, 5
The mixture was cooled to 5 ° C. and stirred for 30 minutes to obtain an organic fatty acid Na solution.

(Preparation of Aqueous Mixture 1 of Organic Fatty Acid Silver and Instantaneous Grinding and Drying) 15.1 g of the silver halide emulsion A was added to the organic fatty acid Na salt solution, and the mixture was adjusted to pH 8.1 with a sodium hydroxide solution. 1M silver nitrate solution 1
47 ml was added over 7 minutes, the mixture was further stirred for 20 minutes, and water-soluble salts were removed by ultrafiltration while adding pure water. The resulting organic fatty acid silver was particles having an average major axis particle size of 0.8 μm and a coefficient of variation of 10%. This slurry (aqueous mixture 1)
Had a solids content of 5%.

Next, this slurry was sent to a high-speed instantaneous flash dryer shown in FIG. 1 by a pump, and dried instantaneously under the conditions shown in Table 1 to obtain fine powder-1.

(Preparation of Aqueous Mixture 2 of Organic Fatty Acid Silver and Instantaneous Grinding and Drying)
After adding 15.1 g of the silver halide emulsion A to the solution and adjusting the pH to 8.1 with a sodium hydroxide solution, 147 ml of a 1 M silver nitrate solution was added over 7 minutes, and the mixture was further stirred for 20 minutes to obtain an aqueous mixture of organic fatty acid silver. I got Next, 10 L of pure water was added to the aqueous mixture, and the mixture was sufficiently stirred and then filtered to remove water-soluble salts. This operation was further repeated three times to obtain a wet cake (aqueous mixture 2) having a solid content of 15% by weight. Next, this wet cake was sent to a high-speed instantaneous flash dryer shown in FIG. 1 by a screw feeder, and was instantaneously dried under the conditions shown in Table 1 to obtain fine powder-2.

(Preparation of Aqueous Mixture 3 of Organic Fatty Acid Silver and Instantaneous Grinding and Drying)
After adding 15.1 g of the silver halide emulsion A to the solution and adjusting the pH to 8.1 with a sodium hydroxide solution, 147 ml of a 1 M silver nitrate solution was added over 7 minutes, and the mixture was further stirred for 20 minutes to obtain an aqueous mixture of organic fatty acid silver. I got Next, 10 L of pure water was added to the aqueous mixture, and the mixture was sufficiently stirred and filtered by suction to remove water-soluble salts. This operation was repeated three more times, and finally suction filtration was performed well to obtain a wet cake (aqueous mixture 3) having a solid content of 20% by weight. Next, this wet cake was sent to a high-speed instantaneous flash dryer shown in FIG. 1 by a screw feeder, and was instantaneously dried under the conditions shown in Table 1 to obtain fine powder-3.

(Preparation of Aqueous Mixture 4 of Organic Fatty Acid Silver and Instantaneous Grinding and Drying) In the preparation of the above-mentioned aqueous mixture 3, the obtained wet cake having a solid content of 20% by weight was dried with a vacuum dryer until the solid content became 90%. The cake was lightly crushed with a pestle to obtain a cake (aqueous mixture 4) several millimeters in size. Next, the cake was sent to a high-speed instantaneous flash dryer using a screw feeder to obtain fine powder-4 which was instantaneously dried under the conditions shown in Table 1.

Comparative Example 1 (Preparation of Dried Product 5 of Aqueous Mixture of Organic Fatty Acid Silver) A wet cake having a solid content of 15% by weight prepared in the same manner as that of Aqueous Mixture 2 was spread on a vat and dried by blowing air at 45 ° C. for 72 hours.
It was completely dried into a cracked plate.

Comparative Example 2 (Preparation of Dried Product 6 of Aqueous Mixture of Organic Fatty Acid Silver) A wet cake having a solid content of 15 wt% prepared in the same manner as that of Aqueous Mixture 2 was spread on a vat and dried at 45 ° C. in a vacuum drier for 8 hours.
It was completely dried into a cracked plate.

<Preparation of Photosensitive Emulsion> After dissolving 120 g of polyvinyl butyral (average molecular weight: 3000) in 700 g of methyl ethyl ketone and 80 g of toluene, 100 g was prepared.
Of the organic fatty acid silver fine powder-1 was added, and a liquid stirred with a disper was prepared. High pressure homogenizer 8000ps
The resulting mixture was dispersed in i to prepare photosensitive emulsion 1. Photosensitive emulsions 2 to 4 were prepared in the same manner for fine powders -2 to 4 of organic fatty acid silver. Regarding the dried products 5 and 6 of the organic fatty acid silver, since the dried product was a lump of several cm, it was gently ground in a mortar and turned into a powder, and then similarly dispersed with a high-pressure homogenizer at 8000 psi. The emulsions were dispersed twice to prepare photosensitive emulsions 5 and 6.

<Preparation of PET-undercoated photographic support> A corona discharge treatment of 8 W / m ² · min was applied to both sides of a commercially available biaxially stretched and heat-fixed 100 μm thick PET film.
On one surface, the following undercoating coating solution a-1 was dried to a thickness of 0.8 μm.
And then dried to form a subbing layer A-1. On the other side, the following antistatic coating subbing coating solution b-1 is applied to a dry film thickness of 0.8 μm and dried. In this way, an antistatic subbing layer B-1 was obtained.

<< Undercoat Coating Solution a-1 >> Butyl acrylate (30% by weight) t-butyl acrylate (20% by weight) Styrene (25% by weight) 2-hydroxyethyl acrylate (25% by weight) copolymer latex liquid (Solid content 30%) 270 g (C-1) 0.6 g Hexamethylene-1,6-bis (ethylene urea) 0.8 g Finish to 1 liter with water << Undercoat coating solution b-1 >> Butyl acrylate (40% by weight) ) Styrene (20% by weight) Glycidyl acrylate (40% by weight) copolymer latex liquid (solid content 30%) 270 g (C-1) 0.6 g Hexamethylene-1,6-bis (ethylene urea) 0.8 g Finish to 1 liter with water Then, on the upper surface of the undercoat layer A-1 and the undercoat layer B-1,
A corona discharge of 8 w / m ² · min. Was performed, and the following lower coating liquid a-2 was coated on the lower coating layer A-1 with a dry film thickness of 0.1 μm.
The lower coating layer B-2 is coated with the following coating liquid b-2 on the lower coating layer B-1 so as to have a dry film thickness of 0.8 μm. Coated as B-2.

<< Coating Solution a-2 for Subbing Upper Layer >> Gelatin 0.4 g / m ² Weight (C-1) 0.2 g (C-2) 0.2 g (C-3) 0.1 g Silica particles ( (Average particle size: 3 μm) 0.1 g Finished to 1 liter with water << Lower upper layer coating solution b-2 >> (C-4) 60 g Latex solution containing (C-5) as a component (solid content: 20%) 80 g Ammonium sulfate 5 g (C-6) 12 g Polyethylene glycol (weight average molecular weight 600) 6 g Finish to 1 liter with water

[0119]

Embedded image

[0120]

Embedded image

(Heat Treatment of Support) In the above-described undercoat drying step of the support, the support was heated at 140 ° C.
Thereafter, it was gradually cooled.

<< Preparation of Photosensitive Material >> Sample 1 was prepared by sequentially forming the following layers on the support. The drying was performed at 60 ° C. for 15 minutes. Samples 2 to 6 were prepared by changing photosensitive emulsion 1 to photosensitive emulsions 2 to 6, respectively.

Back side coating: A solution having the following composition was applied.

Cellulose acetate (10% methyl ethyl ketone solution) 15 ml / m ² dye-B 7 mg / m ² dye-C 7 mg / m ² Matting agent: monodispersity 15% Average particle size 10 μm monodisperse silica 30 mg / m ² C _{9 H 17 -C 6 H 4 -SO 3} Na 10mg / m 2

[0125]

Embedded image

Photosensitive layer surface side coating Photosensitive layer 1: A solution having the following composition was coated and the silver amount was 2.1 g / m ^2.
It was applied so that it became.

Photosensitive emulsion 1 240 g Sensitizing dye-1 (0.1% methanol solution) 1.7 ml Pyridinium bromide perbromide (6% methanol solution) 3 ml Calcium bromide (0.1% methanol solution) 1.7 ml Antifoggant-2 (10% methanol solution) 1.2 ml 2- (4-chlorobenzoylbenzoic acid (12% methanol solution) 9.2 ml 2-mercaptobenzimidazole (1% methanol solution) 11 ml tribromomethylsulfoquinoline ( 5% methanol solution) 17 ml Reducing agent A-4 (20% methanol solution) 29.5 ml

[0128]

Embedded image

Surface protective layer: A solution having the following composition was applied on the photosensitive layer.

Acetone 35 ml / m ² Methyl ethyl ketone 17 ml / m ² Cellulose acetate 2.3 g / m ² Methanol 7 ml / m ² Phthalazine 250 mg / m ² 4-Methylphthalic acid 180 mg / m ² Tetrachlorophthalic acid 150 mg / m ² Tetrachlorophthale Acid anhydride 170 mg / m ² Matting agent: Monodispersity 10% Average particle size 4 μm Monodispersed silica 70 mg / m ² C ₉ H ₁₇ -C ₆ H ₄ -SO ₃ Na 10 mg / m ² << Evaluation of fog performance >> 820 nm diode After exposing the photosensitive material with a laser sensitometer equipped with
After processing (developing) at 15 ° C. for 15 seconds, the obtained image was evaluated using a densitometer. Dmin is a value measured by an optical densitometer and is shown in Table 1.

<< Evaluation of Dispersibility in Next Step >> A photosensitive emulsion obtained by dispersing the fine powders of organic fatty acid silver-1 to 4 and dried products 5 and 6 once with a high-pressure homogenizer at 8000 psi was applied to a slide glass. The size and number of the aggregates were relatively compared in five stages at a magnification of 100 times with an optical microscope. A sample having a small and small aggregate was set to 1, while a sample having a large aggregate and a large number was set to 5.

[0132]

[Table 1]

Example 2 The fog performance of Samples 7 to 9 prepared in the same manner as for Fine Powder-2 used in Sample 2 except that the drying time shown in Table 2 was used, was evaluated.

[0134]

[Table 2]

Example 3 Samples 10 to 1 prepared in the same manner as Fine Powder-2 used in Sample 9 except that the operation was performed so that the water content shown in Table 3 was obtained.
Fog performance evaluation of No. 2 was performed.

[0136]

[Table 3]

[0137]

The organic silver salt obtained by the method of the present invention can be easily produced in a short period of time, has good redispersibility in the next step, and can be subjected to photothermographic exposure using the obtained organic silver salt. The material was good with low fog.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an example of a high-speed instantaneous flash dryer used in the present invention.

[Explanation of symbols]

 Reference Signs List 1 Hot air inlet 2 Slurry material inlet 3 Wet cake inlet 4 Drying chamber 5 Recovery unit A Drying zone B Ascending unit C Crushing and classifying unit

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H123 AB00 AB23 BC00 BC11 CB00 CB03 3L113 AA08 AB03 AC01 AC40 AC44 AC67 BA36 DA24

Claims (9)

[Claims] 1. A method for producing an organic silver salt composition, comprising drying and / or pulverizing a slurry or a wet cake containing an organic silver salt in a high-speed air stream. 2. The method according to claim 1, wherein the high-speed airflow is a swirling flow. 3. A method for producing an organic silver salt composition, comprising drying and / or pulverizing a slurry or a wet cake containing an organic silver salt in swirling hot air. 4. A method for producing an organic silver salt composition, comprising drying and / or pulverizing a slurry or a wet cake containing an organic silver salt in a cylindrical device. 5. The method for producing an organic silver salt composition according to claim 1, wherein the drying and / or grinding is performed for 7 seconds or less. 6. The method for producing an organic silver salt composition according to claim 1, wherein the water content is 10% or less. 7. An organic silver salt composition having a water content of 10% or less. 8. A photothermographic material comprising the organic silver salt composition according to claim 7. 9. A photothermographic material comprising an organic silver salt composition produced by the production method according to claim 1. Description: