JP2003295383A - Method for producing heat-developable photosensitive material, heat-developable photosensitive material, image recording method and imaging method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a heat-developable photosensitive material having high covering power and high sensitivity, less liable to fog and ensuring improved silver image preservability, silver tone and image quality after development and to provide a heat-developable photosensitive material, an image recording method and an imaging method. <P>SOLUTION: The method for producing a heat-developable photosensitive material comprising a non-photosensitive organic silver salt, a photosensitive silver halide, a reducing agent capable of reducing the silver ion of the non- photosensitive organic silver salt to silver when activated by heat, a binder and a crosslinking agent for the binder includes a step for reacting the non- photosensitive organic silver salt with a halogen supplier at the separation temperature of an organic acid constituting the non-photosensitive organic silver salt to a temperature below the dissolution temperature of the organic acid and a step for adsorbing a sensitizing dye on the photosensitive silver halide at the dissolution temperature of the organic acid or above. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-developable material for forming an image by heat development, which has high covering power, high sensitivity and little fog, and has a silver image storability after development and a silver tone and image quality. And a photothermographic material, an image recording method and an image forming method.

[0002]

2. Description of the Related Art In recent years, in the fields of printing and plate making and medical treatment, a waste liquid caused by wet processing of image forming materials has become a problem in terms of workability. Weight loss is strongly desired. Therefore, there is a need for a technology relating to photothermographic materials for photographic technology, in which a laser imagesetter can be efficiently exposed by a laser imager and can form a clear black image with high resolution. Examples of this technique include U.S. Pat. Nos. 3,152,904 and 3,48.
7,075 and D.I. "Dry Silver Photographic Material (Dry Silver P by Morgan)
photographic Materials "(H
andbook of Imaging Material
als, Marcel Dekker, Inc. Fourth
The method described in page 8, 1991) is well known.
Since these photosensitive materials are usually developed at a temperature of 80 ° C. or higher, they are called thermal development materials.

Such a photothermographic material is usually a photothermographic material containing photosensitive silver halide grains, an organic silver salt, a reducing agent for silver ions and a hydrophobic binder on a support.
Silver halide grains are included to provide photosensitivity. In this photothermographic material, a layer is formed by a binder which is softened by heat in order to form an image by dissolving physical development in the layer by heat, and an organic silver salt as a silver ion source and a photosensitive layer are formed in this layer. And a reducing agent are included. When the photothermographic material having such a structure is heated, the silver halide exposed to light becomes a physical development nucleus, and the organic silver salt, which is the built-in silver ion source, reacts with the reducing agent to develop. Progresses to form an image. It is characterized in that development proceeds without supplying reagents or water from the outside and fixing is not performed. Therefore, it is possible to provide the user with a simpler system that does not damage the environment.

On the other hand, since the photothermographic material contains an organic silver salt, photosensitive silver halide grains, and a reducing agent, not only fog tends to occur during the storage period before thermal development and during thermal development, but also the thermal development. There is a problem that fog or photodecomposed silver (printed-out silver) is likely to occur even during the storage period after development processing. Particularly, in the light-sensitive material, after exposure, it is usually 80 to 2
Since heat development is only performed at 50 ° C and fixing is not performed, the silver image discolors due to heat or light during long-term storage under conditions where the silver halide, organic silver salt and reducing agent remaining in the unexposed area are present. It was a problem to do.

That is, the presence of a reducing agent in the light-sensitive material facilitates the formation of thermal fog due to the reaction with the organic silver salt, and the wavelength region different from the light for image recording after development. In addition to the original function of reducing silver ions when they are irradiated with light, they also function as hole traps, etc., so printout silver can be used in systems containing silver halide grains and organic silver salts. It can be considered as one of the causes that the value becomes large.

In addition to the above causes, it is conceivable that fog nuclei causing fog formation are formed in the process of manufacturing the photosensitive material.

Techniques for solving these problems are disclosed in JP-A-6-208192, JP-A-8-267934, US Pat. No. 5,714,311 and the references cited in these patent documents. Although these disclosed technologies have some effects, they are still not sufficient as technologies for satisfying the level required in the market.

[0008]

Therefore, the present invention has been made in view of the above circumstances, and the problems of the present invention are as follows.
High covering power, high sensitivity and less fog,
Another object of the present invention is to provide a method for producing a photothermographic material, a photothermographic material, an image recording method, and an image forming method, which have improved silver image storability after development and silver tone and image quality.

[0009]

The first method for producing a photothermographic material of the present invention comprises a non-photosensitive organic silver salt, a photosensitive silver halide, and the non-photosensitive organic silver when activated by heat. In a method for producing a photothermographic material containing a reducing agent capable of reducing silver ions of a salt to silver, a binder, and a crosslinking agent for the binder, an organic acid precipitation temperature of an organic acid constituting the non-photosensitive organic silver salt A step of reacting the non-photosensitive organic silver salt with a halogen supplier at a temperature lower than the organic acid dissolution temperature,
And a step of adsorbing a sensitizing dye to the photosensitive silver halide at a temperature of dissolving an organic acid or higher.

The temperature difference between the step of reacting the non-photosensitive organic silver salt and the halogen donor and the step of adsorbing the sensitizing dye to the photosensitive silver halide is preferably 5 ° C. or more.

The second photothermographic material of the present invention is obtained by the method for producing the first photothermographic material of the present invention.

The image recording method of the third invention is characterized in that the photothermographic material of the second invention is exposed by a laser exposure machine.

The image forming method of the fourth aspect of the present invention is characterized in that the photothermographic material of the second aspect of the present invention is developed by heating at a temperature of 80 ° C. to 200 ° C.

The image forming method of the fifth aspect of the present invention is characterized in that the photothermographic material exposed by the image recording method of the third aspect of the present invention is developed by heating at a temperature of 80 ° C. to 200 ° C. And

In the following description, unless otherwise specified, the first to fifth inventions are collectively referred to as the present invention.

The organic acid precipitation temperature and the organic acid dissolution temperature in the present invention are temperatures measured by the following method. Methyl ethyl ketone (hereinafter abbreviated as MEK) polyvinyl butyral powder (Sekisui Chemical Co., Ltd., S-REC BL-5) 1
%, And an organic acid constituting the non-photosensitive organic silver salt contained in the photothermographic material are added so as to be 2% by mass, and the temperature is raised with stirring to completely dissolve. Next, the temperature of this solution is slowly lowered, and the temperature at which the organic acid precipitates is measured.
The temperature at which this organic acid precipitates is the organic acid precipitation temperature. Then, the temperature is slowly raised again, the dissolution start temperature (the temperature at which the cloudiness starts to become thin) and the dissolution end temperature (the temperature at which the cloudiness disappears) are measured, and the dissolution end temperature is defined as the organic acid dissolution temperature.

Although the organic acid precipitation temperature and the organic acid dissolution temperature are different depending on the composition of the non-photosensitive organic silver salt contained in the photothermographic material (type of organic silver salt, composition ratio), it cannot be unconditionally determined. The organic acid precipitation temperature is 1 to 20 ° C, and the organic acid dissolution temperature is 15 to 40 ° C.

The present invention will be described below in order. (Photosensitive silver halide) The photosensitive silver halide according to the present invention will be described. The photosensitive silver halide according to the present invention functions as an optical sensor. In the present invention, in order to suppress white turbidity after image formation to a low level and to obtain good image quality, it is preferable that the photosensitive silver halide grains have a small average grain size, and the average grain size is 0.1 μm or less, and more preferable. Is 0.01 μm to 0.1 μm, especially 0.02
μm to 0.08 μm is preferable. The particle size as used herein refers to the diameter of a circle (equivalent circle diameter) having the same area as each particle image observed with an electron microscope. The silver halide is preferably monodisperse. The monodispersion as used herein means that the monodispersity calculated by the following formula is 40% or less,
The particles are preferably 30% or less, particularly preferably 20% or less.

Monodispersity = (standard deviation of grain size) / (average value of grain size) × 100 The shape of silver halide grains is not particularly limited,
The ratio of the Miller index [100] plane is preferably high, and the ratio is preferably 50% or more, more preferably 70% or more, and particularly preferably 80% or more. Miller index [10
The ratio of the [0] plane is measured by the T.O. Tani,
J. Imaging Sci. , 29, 165 (198
It can be determined by 5).

Another preferred form of silver halide is tabular grain. The tabular grain here means the square root of the projected area with a grain size of rμm, and a vertical thickness of hμm.
In this case, the aspect ratio = r / h is 3 or more. Among them, the aspect ratio is 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 US Pat. Nos. 5,264,337 and 5,31
No. 4,798,5,320,958, etc., and the desired tabular grains can be easily obtained.

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. The photographic emulsion used in the present invention is described in P. Chimie et by Glafkides
Physique Photographique (P
aul Montel, 1967), G.A. F. D
by Uffin Photographic Emuls
ion Chemistry (The Focal P
Press, 1966), V.I. L. Zelikman
Et al. Making and Coating
Photographic Emulsion (Th
e Focal Press, 1964) and the like. That is, any of an acidic method, a neutral method, an ammonia method, etc. may be used, and as a formation for reacting a soluble silver salt and a soluble halogen salt, any one of a one-sided mixing method, a simultaneous mixing method and a combination thereof may be used. Good.

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

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

In the general formula [ML ₆ ] ^m , M is a transition metal selected from the 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 (fluorides, chlorides, bromides and iodides), cyanides, cyanates, thiocyanates, selenocyanates,
Tellurocyanate, azide and aco ligands, nitrosyl, thionitrosyl and the like, and preferably aco,
Examples include nitrosyl and thionitrosyl. When an aco ligand is present, it preferably occupies one or two of the ligands. L may be the same or different.

Particularly preferred specific 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 thereto.

[0027] 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] ^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) Cl (CN) 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- 28: [Fe (CN) ₆ ] ^4- 29: [Fe (CN) ₆ ] ^3- 30: [Ru (CN) ₆ ] ^{4 -} 31: [Os (CN) _6] ^4- 32: [Co (CN) _6] ^3- 33: [Rh (CN) _6] ^3- 34: [Ir (CN) _6] ^3- 35: [Cr ( CN) ₆ ] ^3- 36: [Re (CN) ₆ ] ^3- These metal ions, metal complexes or metal complex ions may be of one kind, or the same kind of metal and two or more kinds of different metals may be used in combination. Good. The content of these metal ions, metal complexes or metal complex ions is generally 1 × 10 ⁻⁹ to 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 at the time of silver halide grain formation and incorporated into the silver halide grains. Preparation of silver halide grains, that is, nucleation, growth, physical ripening, chemical It may be added at any stage before and after the sensitization, but it is particularly preferable to add it 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.

Upon addition, the silver halide may be added dividedly over several times, or may be uniformly contained in the silver halide grains.
-306236, 3-167545, 4-76
No. 534, No. 6-110146, No. 5-273683.
It is also possible to contain the particles having a distribution as described in No. Preferably, it can have a distribution inside the particles.

These metal compounds can be added after being dissolved in water or a suitable organic solvent (eg alcohols, ethers, glycols, ketones, esters, amides). A method of adding an aqueous solution of the powder of (1) or an aqueous solution of a metal compound and NaCl, KCl together 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. When mixed at the same time, it is added as a third aqueous solution to prepare silver halide grains by a three-liquid simultaneous mixing method, a method in which a necessary amount of an aqueous solution of a metal compound is charged into a reaction vessel during grain formation, or a halogen There is a method of adding and dissolving another silver halide grain which is previously doped with a metal ion or a complex ion at the time of preparing silver halide. 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 or KCl are dissolved together to a water-soluble halide solution is preferable.

When added to the surface of the particles, a necessary amount of the aqueous solution of the metal compound may be added to the reaction vessel immediately after the particles are formed, during or during physical ripening, or at the end of chemical ripening.

In the present invention, the photosensitive silver halide grains may or may not be desalted after grain formation, but when desalting is performed, it is known in the art such as noodle method and flocculation method. It can be desalted by washing with water according to the method described above.

The photosensitive silver halide prepared by the above-mentioned various methods includes, for example, sulfur-containing compounds, gold compounds,
Platinum compound, palladium compound, silver compound, tin compound,
Chemical sensitization can be performed with a chromium compound or a combination thereof. For the method and procedure of this chemical sensitization, see, for example, US Pat. No. 4,036,650,
British Patent No. 1,518,850, JP-A-51-
No. 22430, No. 51-78319, No. 51-811
It is described in each publication of No. 24. In order to achieve sensitization, as described in US Pat. No. 3,980,482, when a part of an organic silver salt is converted into a photosensitive silver halide by a silver halide forming component. A low molecular weight amide compound may coexist with.

(Non-Photosensitive Organic Silver Salt) The non-photosensitive organic silver salt according to the present invention will be described. In the present invention, the non-photosensitive organic silver salt is a reducible silver source, and is a silver salt of an organic acid or a heteroorganic acid, especially a long-chain (having 10 to 3 carbon atoms).
0, preferably 15 to 25) Silver salts of aliphatic carboxylic acids and nitrogen-containing heterocyclic compounds are preferred. Organic or inorganic complexes in which the ligand has a total stability constant for silver ions of 4.0 to 10.0 are also preferable. Examples of these suitable silver salts include Research Discros.
ure Nos. 17029 and 29963, including:

Organic acids such as silver salts of gallic acid, oxalic acid, behenic acid, stearic acid, arachidic acid, palmitic acid and lauric acid, carboxyalkylthiourea salts of silver,
For example, 1- (3-carboxypropyl) thiourea, 1
Silver salts such as-(3-carboxypropyl) -3,3-dimethylthiourea, silver salts or complexes of polymer reaction products of aldehydes with hydroxy-substituted aromatic carboxylic acids, such as aldehydes (formaldehyde, acetaldehyde, butyraldehyde) Etc.), a silver salt or complex of a reaction product of hydroxy-substituted acids (for example, salicylic acid, benzoic acid, 3,5-dihydroxybenzoic acid, 5,5-thiodisalicylic acid), a silver salt or complex of thioenes, for example, 3-
(2-Carboxyethyl) -4-hydroxymethyl-4
-Thiazolin-2-thioene, and silver salts or complexes such as 3-carboxymethyl-4-thiazoline-2-thioene,
Imidazole, pyrazole, urazole, 1,2,4-
Thiazole and 1H-tetrazole, 3-amino-5-
A complex or salt of a nitric acid and silver selected from benzylthio-1,2,4-triazole and benzotriazole,
Examples thereof include silver salts such as saccharin and 5-chlorosalicylaldoxime, and silver salts of mercaptides. Among these, preferred silver salts are silver behenate, silver arachidate and silver stearate.

The non-photosensitive organic silver salt is obtained by mixing a compound which forms a complex with silver and a water-soluble silver compound. As the mixing method, there are a forward mixing method, a reverse mixing method, a simultaneous mixing method and the like, and the controlled double jet method described in JP-A-9-127643 is preferably used. For example, by adding an alkali metal salt (eg, sodium hydroxide, potassium hydroxide, etc.) to an organic acid to make an organic acid alkali metal salt soap (eg, sodium behenate, sodium arachidate), and then using a control double jet. The organic acid alkali metal salt soap and silver nitrate are added to prepare organic silver salt crystals. At that time, silver halide grains may be mixed.

In the present invention, the non-photosensitive organic silver salt preferably has an average particle diameter of about 2 μm or less and is monodisperse. The average particle size of the non-photosensitive organic silver salt is a sphere equivalent to the volume of the non-photosensitive organic silver salt particle when the non-photosensitive organic silver salt particles are, for example, spherical, rod-shaped or tabular particles. The diameter when considering. The average particle size is preferably 0.05 μm to 1.5 μm, particularly 0.05 μm to 1.0
μm is preferred. Further, the monodispersion has the same meaning as in the case of silver halide, and the monodispersity is preferably 1 to 30%.

In the present invention, the tabular grains of the non-photosensitive organic silver salt preferably account for 60% or more of the total non-photosensitive organic silver salt. In the present invention, the tabular grains mean those having a ratio of average grain size to thickness, that is, an aspect ratio (abbreviated as AR) represented by the following formula of 3 or more.

AR = average particle size (μm) / thickness (μm) In order to form the non-photosensitive organic silver salt into these shapes, the organic silver salt crystals are dispersed with a binder or a surfactant by a ball mill or the like. Obtained by crushing. Within this range, a photothermographic material having high density and excellent image storability can be obtained.

In the present invention, in order to prevent devitrification of the photothermographic material, the total amount of the photosensitive silver halide and the non-photosensitive organic silver salt is 0.5 g or more per 1 m ² in terms of silver. It is preferably 2 g or less. Within this range, a high contrast image can be obtained. The amount of silver halide based on the total amount of silver is 50% or less, preferably 25% or less, and more preferably 0.1% to 15% by mass.

(Dispersion of Non-Photosensitive Organic Silver Salt) The tabular non-photosensitive organic silver salt particles according to the present invention are pre-dispersed with a binder, a surfactant and the like, if necessary, and then are dispersed by a media disperser or a high pressure homogenizer. It is preferable to disperse and crush. For the above preliminary dispersion, a general stirrer such as an anchor type or a propeller type, a high-speed rotating centrifugal radiating stirrer (dissolver), or a high-speed rotating shearing stirrer (homomixer) can be used.

As the above-mentioned media disperser, it is possible to use a rolling mill such as a ball mill, a planetary ball mill, a vibrating ball mill, a medium agitating mill such as a bead mill, an attritor, or a basket mill, and a high pressure homogenizer. Various types such as a type that collides with a wall or a plug, a type that divides the liquid into a plurality of liquids and then collides with each other at high speed, a type that passes through a thin orifice, and the like can be used.

Examples of the ceramics used for the ceramic beads used at the time of dispersing the medium include A
l ₂ O ₃ , BaTiO ₃ , SrTiO ₃ , MgO, ZrO,
_{BeO, Cr 2 O 3, SiO} 2, SiO 2 -Al 2 O 3, Cr
₂ O ₃ -MgO, MgO-CaO, MgO-C, MgO-
Al ₂ O ₃ (spinel), SiC, TiO ₂ , K ₂ O, Na
₂ O, BaO, PbO, B ₂ O ₃ , SrTiO ₃ (strontium titanate), BeAl ₂ O ₄ , Y ₃ Al ₅ O ₁₂ , Zr
O ₂ -Y ₂ O ₃ (cubic zirconia), 3BeO-Al ₂ O
₃ -6SiO ₂ (Synthesis emerald), C _{(diamond), Si 2 O-nH 2} O, ticker silicon, yttrium stabilized zirconia, zirconia toughened alumina, and the like are preferable. Yttrium-stabilized zirconia and zirconia-reinforced alumina (ceramics containing these zirconia are abbreviated as zirconia in the following) are particularly preferably used because, for example, impurities are less likely to be generated by friction with beads or a disperser during dispersion.

In the apparatus used for dispersing the tabular organic silver salt particles according to the present invention, as a material of the member with which the organic silver salt particles come into contact, ceramics such as zirconia, alumina, silicon nitride, boron nitride or the like, or It is preferable to use diamond, and above all, it is preferable to use zirconia.

When carrying out the above dispersion, the binder concentration is preferably 0.1 to 10% of the mass of the non-photosensitive organic silver salt, and it is preferable that the liquid temperature does not exceed 45 ° C. from the preliminary dispersion to the main dispersion. The preferred operating conditions for the main dispersion are, for example, 29.42 MPa to 98.06 MPa when a high-pressure homogenizer is used as the dispersion means.
The number of times of operation is preferably 2 or more as a preferable operation condition. When the media disperser is used as the dispersing means, the peripheral speed is preferably 6 m / sec to 13 m / sec.

Further, zirconia can be used as a part of the beads or members and mixed in the dispersion emulsion at the time of dispersion.
This is preferable and effective in terms of photographic performance. Fragments of zirconia may be added later to the dispersion emulsion or may be added in advance at the time of preliminary dispersion. The specific method is not particularly limited, but as an example, by circulating MEK through a bead mill filled with zirconia beads, a high-concentration zirconia solution can be obtained. It may be added at a preferable concentration at a preferable time.

(Reducing Agent) The reducing agent according to the present invention is a reducing agent capable of reducing the silver ion of the non-photosensitive organic silver salt to silver when activated by heat, and a known one can be used. it can. For example, phenols, polyphenols having two or more phenol groups, naphthols, bisnaphthols, polyhydroxybenzenes having two or more hydroxyl groups, polyhydroxynaphthalenes having two or more hydroxyl groups, ascorbic acids, 3-pyrazolidones, pyrazolin-5-ones, pyrazolines, phenylenediamines, hydroxylamines, hydroquinone monoethers, hydrooxamic acids, hydrazides, amidoximes, N-hydroxyureas, and the like. Specifically, for example, U.S. Pat. Nos. 3,615,533, 3,679,426, 3,672,904,
No. 3,751,252, No. 3,782,949
No. 3,801,321, No. 3,794,48
No. 8, No. 3,893,863, No. 3,887,3
No. 76, No. 3,770,448, No. 3,819,
No. 382, No. 3,773,512, No. 3,83
No. 9,048, No. 3,887,378, No. 4,0
09,039, 4,021,240, British Patent 1,486,148 or Belgian Patent 78.
No. 6,086 and JP-A-50-36143,
50-36110, 50-116023, 5
0-99719, 50-140113, 51-
No. 51933, No. 51-23721, No. 52-847.
No. 27 or Japanese Patent Publication No. 51-35851, there are reducing agents specifically exemplified, and the present invention can be appropriately selected and used from such known reducing agents.
The simplest selection method is to actually produce a photothermographic material and evaluate the photographic performance of the photothermographic material to check the superiority or inferiority of the reducing agent used.

Among the above reducing agents, when an aliphatic carboxylic acid silver salt is used as the non-photosensitive organic silver salt, a preferable reducing agent is a polyphenol in which two or more phenol groups are linked by an alkylene group or sulfur. Group, particularly an alkyl group (eg, methyl group, ethyl group, propyl group, t-butyl group, cyclohexyl group, etc.) or acyl group (eg, acetyl group, propionyl group) at least at one position adjacent to the hydroxy-substituted position of the phenol group. Etc.) substituted polyphenols in which two or more of the phenol groups are linked by an alkylene group or sulfur, for example, 1,1-bis (2-hydroxy-3,5-dimethylphenyl)-
3,5,5-Trimethylhexane, 1,1-bis (2-
Hydroxy-3-t-butyl-5-methylphenyl) methane, 1,1-bis (2-hydroxy-3,5-di-t
-Butylphenyl) methane, 2-hydroxy-3-t-
Butyl-5-methylphenyl- (2-hydroxy-5-
Methylphenyl) methane, 6,6'-benzylidene-bis (2,4-di-t-butylphenol), 6,6'-
Benzylidene-bis (2-t-butyl-4-methylphenol), 6,6'-benzylidene-bis (2,4-dimethylphenol), 1,1-bis (2-hydroxy-)
3,5-dimethylphenyl) -2-methylpropane,
1,1,5,5-tetrakis (2-hydroxy-3,5
-Dimethylphenyl) -2,4-ethylpentane, 2,
2-bis (4-hydroxy-3,5-dimethylphenyl) propane, 2,2-bis (4-hydroxy-3,5)
U.S. Pat. Nos. 3,589,903, 4,021,249 or British Patent 1,486,148, such as -di-t-butylphenyl) propane, and JP-A-51-51933. , Ibid. 50-36110, ibid. 50
No. 116023, No. 52-84727 or Japanese Patent Publication No. 51-35727, bisnaphthols described in US Pat. No. 3,672,904, for example, 2,2′- Dihydroxy-1,1'-binaphthyl, 6,6'-dibromo-
2,2'-dihydroxy-1,1'-binaphthyl, 6,
6'-dinitro-2,2'-dihydroxy-1,1'-
Binaphthyl, bis (2-hydroxy-1-naphthyl) methane, 4,4′-dimethoxy-1,1′-dihydroxy-2,2′-binaphthyl, and the like, and US Pat.
Sulfonamide phenols or sulfonamide naphthols as described in 1,321, eg 4-benzenesulfonamidophenol, 2-benzenesulfonamidophenol, 2,6-dichloro-4.
-Benzenesulfonamidophenol, 4-benzenesulfonamidonaphthol, etc. can be mentioned.

The amount of reducing agent used in the present invention is
Although it depends on the type of non-photosensitive organic silver salt or reducing agent and other additives, it is generally 0.0 per mol of the organic silver salt.
5 mol-10 mol, preferably 0.1 mol-3 mol are suitable. Also, within the range of this amount, two or more of the above-mentioned reducing agents may be used in combination.

(Toning Agent) In the present invention, it is desirable to use an additive called a toning agent, a toning agent or an activator toner (hereinafter referred to as a toning agent) together with the above components. The toning agent has a function of participating in the redox reaction between the non-photosensitive organic silver salt and the reducing agent to make the resulting silver image a dark color, especially black. Examples of suitable toning agents for use in the present invention are Research Disclosure No. 17
No. 029, and 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 2). , 4-thiazolidinedione); naphthalimides (for example, N-hydroxy-1,8-naphthalimide); cobalt complex (for example, hexaminetrifluoroacetate of cobalt), mercaptans (for example, 3
-Mercapto-1,2,4-triazole); N- (aminomethyl) aryldicarboximides (e.g.,
N- (dimethylaminomethyl) phthalimide); blocked pyrazoles, isothiuronium (isoth
iuronium) derivative and certain photobleaching agents (eg, N, N'-hexamethylene (1-carbamoyl-3,5-dimethylpyrazole), 1,8-
(Combination of (3,6-dioxaoctane) bis (isothiuronium trifluoroacetate) and 2- (tribromomethylsulfonyl) benzothiazole); merocyanine dye (for example, 3-ethyl-5-((3-ethyl 2-Benzothiazolinylidene (benzothiazolinylidene))-1-methylethylidene) -2-thio-2,4
-Oxazolidinedione); phthalazinone, phthalazinone derivatives or metal salts 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 + phthal Acid combination; phthalazine (including phthalazine adduct) and maleic anhydride,
And phthalic acid, 2,3-naphthalenedicarboxylic acid or o
At least one selected from phenylene acid derivatives and their anhydrides (eg phthalic acid, 4-methylphthalic acid, 4-nitrophthalic acid and tetrachlorophthalic anhydride)
A combination of two compounds; quinazolinediones, benzoxazine, naltoxazine derivatives; benzoxazine-2,4-diones (for example, 1,3-benzoxazine-2,4-dione); pyrimidines and asymmetric-triazines. (For example, 2,4-dihydroxypyrimidine), and a tetraazapentalene derivative (for example, 3,
6-dimercapto-1,4-diphenyl-1H, 4H-
2,3a, 5,6a-tetraazapentalene). A preferable color tone agent is phthalazone or phthalazine.

(Binder) The binder according to the present invention is transparent or translucent and generally colorless, and is a natural polymer, a synthetic polymer or the like. Specifically, as the film-forming polymer, for example, gelatin, gum arabic,
Polyvinyl alcohol, hydroxyethyl cellulose,
Cellulose acetate, cellulose acetate butyrate, polyvinylpyrrolidone, casein, starch, polyacrylic acid, polymethylmethacrylate, polymethacrylic acid, polyvinyl chloride, copoly (styrene-maleic anhydride), copoly (styrene-acrylonitrile), copoly (styrene) -Butadiene), polyvinyl acetals,
For example, polyvinyl formal, polyvinyl butyral, polyesters, polyurethanes, phenoxy resins, polyvinylidene chloride, polyepoxides, polycarbonates, polyvinyl acetates, cellulose esters, polyamides and the like, which may be water-soluble or water-insoluble . However, among these binders, water-insoluble polymers such as cellulose acetate, cellulose acetate butyrate and polyvinyl butyral are particularly preferable, and polyvinyl butyral is particularly preferable among them.

In the present invention, the binder amount in the photosensitive layer is preferably 1.5 to 6 g / m ² . More preferably, it is 1.7 to 5 g / m ² . If it is less than 1.5 g / m ² , the density of the unexposed area may increase significantly and it may not be usable.

(Cross-linking agent) The binder can maintain the adhesion to the lower layer and the upper layer by forming a film alone, and can obtain a film strength that is less likely to be scratched. Adhesion and film strength can be increased.
However, if the crosslinking reaction is slow, the photographic performance is not stable and the storage stability is deteriorated. Examples of the quick-acting and preferable crosslinking agent used in the present invention include a polyfunctional crosslinking agent having at least two isocyanate groups, epoxy groups, or vinylsulfonyl groups, and an alkoxysilane compound.
Preferred crosslinking agents are shown below.

H1 hexamethylene diisocyanate H2 hexamethylene diisocyanate trimer H3 tolylene diisocyanate H4 phenylene diisocyanate H5 xylylene diisocyanate The cross-linking agent is water, alcohols, ketones or non-polar It may be added by being dissolved in an organic solvent, or may be added as a solid in the coating liquid. The addition amount is preferably equivalent to the crosslinkable group of the binder, but may be increased up to 10 times, or 1
The amount may be reduced to 1/0 or less. If the amount is too small, the crosslinking reaction will not proceed, and if it is too large, the unreacted crosslinking agent deteriorates the photographic properties, which is not preferable.

(Matting Agent) In the present invention, it is preferable to contain a matting agent on the photosensitive layer side, and it is preferable to dispose a matting agent on the surface of the light-sensitive material in order to prevent scratching of the image after heat development. It is preferable that the matting agent is contained in an amount of 0.5 to 30% by mass with respect to the total binder on the photosensitive layer side.

When a non-photosensitive layer is provided on the side opposite to the photosensitive layer with respect to the support, it is preferable to include a matting agent in at least one layer on the non-photosensitive layer side so that the photothermographic material can have good slipperiness and fingerprints. It is preferable to dispose a matting agent on the surface of the light-sensitive material also for prevention of adhesion, and the matting agent is 0.5 to 0.5 by mass ratio with respect to all binders in the layer opposite to the light-sensitive layer side.
It is preferable to contain 40%.

The matting agent used in the present invention may be organic or inorganic. For example, as the inorganic substance, silica described in Swiss Patent No. 330,158, glass powder described in French Patent No. 1,296,995, and alkali described in British Patent No. 1,173,181, etc. An earth metal or a carbonate such as cadmium or zinc can be used as a matting agent. As organic matter,
Starch described in US Pat. No. 2,322,037, Belgian patent 625,451 and British patent 981,19
No. 8, etc., starch derivative, Japanese Examined Patent Publication No.
Polyvinyl alcohol described in Swiss Patent No. 33
Polystyrene or polymethacrylate described in US Pat. No. 0,158, polyacrylonitrile described in US Pat. No. 3,079,257, US Pat. No. 3,022,16
Organic matting agents such as polycarbonate described in No. 9 can be used.

The shape of the matting agent may be either a fixed shape or an amorphous shape, but a fixed shape is preferable, and a spherical shape is preferably used. The size of the matting agent is represented by the diameter when the volume of the matting agent is converted into a spherical shape. In the present invention, the particle size of the matting agent refers to the spherically converted diameter.

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

The method for adding the matting agent according to the present invention may be a method in which the matting agent is dispersed in the coating solution in advance and then coated.
A method of spraying the matting agent after applying the coating solution and before the completion of drying may be used. When a plurality of types of matting agents are added, both methods may be used together.

(Halogen supplier) The method for producing a photothermographic material of the present invention comprises a non-photosensitive organic silver salt at a temperature not lower than the organic acid precipitation temperature of the organic acid constituting the non-photosensitive organic silver salt and lower than the dissolution temperature. And a halogen supplier. The reaction is carried out in the solvent used for producing the photothermographic material.

As the halogen supplier, inorganic halogen compounds, onium halides, halogenated hydrocarbons, N
-There are halogen compounds and other halogen-containing compounds,
For specific examples, see US Pat. No. 4,009,039.
No. 3,4,507,753, 4,003,74
No. 9, British Patent Nos. 1,498,956 and JP-A Nos. 53-27027 and 53-25420, inorganics such as silver metal halides, calcium bromide, ammonium halides, etc. Halides, for example, onium halides such as trimethylphenylammonium bromide, cetylethyldimethylammonium bromide, trimethylbenzylammonium bromide,
For example, iodoform, bromoform, carbon tetrachloride,
Halogenated hydrocarbons such as 2-bromo-2-methylpropane, N-halogen compounds such as N-bromosuccinimide, N-bromophthalimide and N-bromoacetamide,
Others, for example, triphenylmethyl chloride, triphenylmethyl bromide, 2-bromoacetic acid, 2-bromoethanol,
Examples include dichlorobenzophenone.

Preference is given to using at least one onium salt having a halide or polyhalide anion. Particularly preferred oniums are organic-phosphonium, organic-sulfonium, and organic-nitrogen onium cations, with heterocyclic nitrogen onium (eg pyridinium), quaternary phosphonium, and tertiary sulfonium cations being preferred. Preferred halide anions are chloride, bromide, and iodide anions. Preferred halide anions include chlorine, bromine, and iodine atoms.

(Sensitizing Dye) In the method for producing a photothermographic material of the present invention, a sensitizing dye is adsorbed on a photosensitive silver halide at a temperature not lower than an organic acid dissolution temperature of an organic acid constituting a non-photosensitive organic silver salt. It is characterized by including a process.

Examples of the sensitizing dye include, for example, JP-A-63-1.
59841, 60-140335, 63-23.
No. 1437, No. 63-259651, No. 63-304
242, 63-15245, U.S. Pat. No. 4,63.
No. 9,414, No. 4,740,455, No. 4,7
41,966, 4,751,175, 4,
The sensitizing dyes described in 835,096 can be used.

In the present invention, the wavelength is 720 nm to 10 nm.
More preferably, it is spectrally sensitized to 00 nm. Useful sensitizing dyes used in the present invention are, for example, Research.
Disclosure Item 17643 IV-A
Section (Dec. 1978, p. 23), or the documents cited or cited. 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, with respect to an argon ion laser light source, JP-A-60-162247 and JP-A-2-486 are available.
35, US Pat. No. 2,161,331, West German Patent No. 936,071, and Japanese Patent Application No. 3-18953.
For the simple merocyanines and the helium neon laser light source described in Japanese Patent No. 2, etc., JP-A-50-624.
No. 25, No. 54-18726, No. 59-102229.
No. 6-1032, the trinuclear cyanine dyes shown in No.
For the merocyanines, LED light sources and infrared semiconductor laser light sources described in No. 72, Japanese Patent Publication No. 48-4217.
No. 2, No. 51-9609, No. 55-39818, and the thiacarbocyanines described in JP-A Nos. 62-284343 and 2-105135, and the infrared semiconductor laser light source are disclosed in JP-A Nos. 59-191032, tricarbocyanines described in JP-A-60-80841, JP-A-59-192242 and JP-A-3-6724.
Dicarbocyanines containing a 4-quinoline nucleus described in the general formulas (IIIa) and (IIIb) of No. 2 are advantageously selected.

Furthermore, the wavelength of the infrared laser light source is 750
When the wavelength is not less than nm, more preferably not less than 800 nm, in order to deal with the laser having such a wavelength range, JP-A-4-182639, JP-A-5-341432 and JP-B-6
-52387, 3-10931, US Pat.
The sensitizing dyes described in JP-A No. 441,866 and JP-A No. 7-13295 are preferably used. These sensitizing dyes may be used alone, and a combination of sensitizing dyes is often used particularly for the purpose of supersensitization. Along with the sensitizing dye, a dye that does not itself have a spectral sensitizing effect or a substance that does not substantially absorb visible light and exhibits supersensitization may be included in the emulsion. As a particularly preferred sensitizing dye, at least one sensitizing dye represented by the following general formula (1) or general formula (2) is used.

[0071]

[Chemical 1]

Where Y_{twenty one}, Y_{twenty two}And Y₃₁Are each oxygen
Atom, sulfur atom, selenium atom, -C (Ra) (Rb)-
A group or a —CH═CH— group, R_{twenty one}, R_{twenty two}, R₃₁
And R₃₂Are each an aliphatic group, and Rc and Rd are each
Lower alkyl group, cycloalkyl group, aralkyl group,
It represents a reel group or a heterocyclic group. Ra and Rb are each low
Alkyl group, cycloalkyl group, aralkyl group, lower alkyl group
It represents a lucoxy group or an aryl group. W_{twenty one}, W_{twenty two}, W_{twenty three}, W
_{twenty four}, W₃₁, W₃₂, W₃₃And W₃₄Are hydrogen atom and substitution
Group or W_{twenty one}Is W_{twenty two}And W_{twenty three}Is W_{twenty four}And W₃₁Is W
₃₂And W₃₃Is W₃₄To bond with and form a condensed ring
Represents the necessary non-metallic atomic group. V_{twenty one}~ V₂₉, V ₃₁~ V₃₃Is
Hydrogen atom, halogen atom, amino group, alkyl group
O group, arylthio group, lower alkyl group, lower alkoxy group
Group, aryl group, aryloxy group, heterocyclic group
Or V_{twenty one}Is V_{twenty three}And V_{twenty two}Is V_{twenty four}And V_{twenty three}Is V
_{twenty five}And V_{twenty four}Is V₂₆And V_{twenty five}Is V₂₇And V₂₆Is V₂₈And V
₂₇Is V₂₉And V₃₁Is V₃₃With 5 to 7 members
Represents a group of non-metal atoms necessary for forming a ring, X_{twenty one}And X
₃₁Represents the ions necessary to cancel the charge in the molecule.
And l21 and l31 each cancel the charge in the molecule.
Represents the number of ions required for. k21 and k22 are respectively
Represents 0 or 1. n21, n22, n31 and n32
Each represents an integer of 0 to 2, n21, n22, and n3
1 and n32 cannot be 0 at the same time.

In the general formulas (1) and (2),
Examples of the aliphatic group represented by R ₂₁ , R ₂₂ , R ₃₁ , and R ₃₂ include
For example, a branched or straight chain alkyl group having 1 to 10 carbon atoms (eg, methyl group, ethyl group, propyl group, butyl group, pentyl group, iso-pentyl group, 2-ethyl-hexyl group, octyl group, decyl group). Groups, etc.), carbon atoms of 3 to
10 alkenyl groups (eg, 2-propenyl group, 3-
Butenyl group, 1-methyl-3-propenyl group, 3-pentenyl group, 1-methyl-3-butenyl group, 4-hexenyl group, etc.), aralkyl group having 7 to 10 carbon atoms (for example, benzyl group, phenethyl group) Etc.) can be mentioned.

The above-mentioned groups further include lower alkyl groups (eg, methyl group, ethyl group, propyl group, etc.), halogen atoms (eg, fluorine atom, chlorine atom, bromine atom, etc.),
Vinyl group, aryl group (eg, phenyl group, p-tolyl group, p-bromophenyl group, etc.), trifluoromethyl group, alkoxy group (eg, methoxy group, ethoxy group,
Methoxyethoxy group, etc.), aryloxy group (eg,
Phenoxy group, p-tolyloxy group, etc.), cyano group, sulfonyl group (eg, methanesulfonyl group, trifluoromethanesulfonyl group, p-toluenesulfonyl group, etc.), alkoxycarbonyl group (eg, ethoxycarbonyl group, butoxycarbonyl group, etc.) , An amino group (eg, amino group, biscarboxymethylamino group, etc.), an aryl group (eg, phenyl group, carboxyphenyl group, etc.), a heterocyclic group (eg, tetrahydrofurfuryl group,
2-pyrrolidinone-1-yl group etc.), acyl group (eg acetyl group, benzoyl group etc.), ureido group (eg ureido group, 3-methylureido group, 3-phenylureido group etc.), thioureido group (eg , Thioureido group, 3-methylthioureido group, etc.), alkylthio group (eg, methylthio, ethylthio group, etc.), arylthio group (eg, phenylthio group, etc.), heterocyclic thio group (eg, 2-thienylthio group, 3-thienylthio group, 2-imidazolylthio group, etc., carbonyloxy group (eg,
Acetyloxy group, propanoyloxy group, benzoyloxy group etc.), acylamino group (eg acetylamino, benzoylamino group etc.), thioamide group (eg
Thioacetamido group, thiobenzoylamino group, etc.) or groups such as sulfo group, carboxy group, phosphono group, sulfate group, hydroxy group, mercapto group, sulfino group, carbamoyl group (eg, carbamoyl group, N-methyl group). Carbamoyl group, N, N-tetramethylenecarbamoyl group, etc., sulfamoyl group (eg, sulfamoyl group, N, N-3-oxapentamethyleneaminosulfonyl group, etc.), sulfonamide group (eg, methanesulfonamide, butanesulfonamide) Groups, etc.), sulfonylaminocarbonyl groups (eg, methanesulfonylaminocarbonyl, ethanesulfonylaminocarbonyl groups, etc.), acylaminosulfonyl groups (eg, acetamidosulfonyl, methoxyacetamidosulfonyl groups, etc.), acyl Amino carbonyl group (e.g.,
It may be substituted with a hydrophilic group such as acetamidocarbonyl, methoxyacetamidocarbonyl group, etc.), sulfinylaminocarbonyl group (eg, methanesulfinylaminocarbonyl group, ethanesulfinylaminocarbonyl group, etc.).

Specific examples of the aliphatic group substituted with these hydrophilic groups include carboxymethyl group, carboxyethyl group, carboxybutyl group, carboxypentyl group and 3
-Sulfatobutyl group, 3-sulfopropyl group, 2-
Hydroxy-3-sulfopropyl group, 4-sulfobutyl group, 5-sulfopentyl group, 3-sulfopentyl group, 3
-Sulfinobutyl group, 3-phosphonopropyl group, hydroxyethyl group, N-methanesulfonylcarbamoylmethyl group, 2-carboxy-2-propenyl group, o-sulfobenzyl group, p-sulfophenethyl group, p-carboxybenzyl group Each group such as a group can be mentioned.

The lower alkyl group represented by Ra and Rb is a linear or branched group having 5 or less carbon atoms, and specifically, methyl group, ethyl group, propyl group, butyl group, pentyl group, isopropyl group. Groups and the like. Examples of the cycloalkyl group include cyclopropyl group, cyclobutyl group and cyclopentyl group, and examples of the aralkyl group include benzyl group, phenethyl group, p-methoxyphenylmethyl group and o-acetylaminophenyl group. Examples of the lower alkoxy group include a group having 4 or less carbon atoms, such as a methoxy group, an ethoxy group, a propoxy group, and an iso-propoxy group. Substitution,
Including unsubstituted ones, for example, phenyl group, 2-naphthyl group, 1-naphthyl group, o-tolyl group, o-methoxyphenyl group, m-chlorophenyl group, m-bromophenyl group, p-tolyl group, p- Examples thereof include groups such as ethoxyphenyl group, and these groups can be substituted with groups such as phenyl group, halogen atom, alkoxy group and hydroxy group. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.

The lower alkyl group represented by Rc and Rd is a straight chain or branched group having 5 or less carbon atoms, specifically, methyl group, ethyl group, propyl group, butyl group, pentyl group, isopropyl group. Groups and the like. Examples of the cycloalkyl group include a cyclopropyl group, a cyclobutyl group,
Examples thereof include a cyclopentyl group and the like, and examples of the aralkyl group include a benzyl group, a phenethyl group, a p-methoxyphenylmethyl group, an o-acetylaminophenylethyl group, and the like, and the aryl group includes substituted and unsubstituted groups. , For example, phenyl group, 2-naphthyl group, 1-naphthyl group, o-tolyl group, o-methoxyphenyl group, m
Groups such as -chlorophenyl group, m-bromophenyl group, p-tolyl group and p-ethoxyphenyl group are included, and the heterocyclic group includes substituted and unsubstituted groups, for example, 2-
Furyl group, 5-methyl-2-furyl group, 2-thienyl group, 2-imidazolyl group, 2-methyl-1-imidazolyl group, 4-phenyl-2-thiazolyl group, 5-hydroxy-2-benzothiazolyl group, 2 Examples thereof include groups such as -pyridyl group and 1-pyrrolyl group. These groups can be further substituted with groups such as the phenyl group, halogen atom, alkoxy group and hydroxy group mentioned in the above description.

The substituents represented by W _{21 to} W ₂₄ and W _{31 to} W ₃₄ are specifically an alkyl group (eg, methyl group, ethyl group, butyl group, iso-butyl group, etc.), aryl group ( Including monocyclic and polycyclic, for example, phenyl group, carboxyphenyl group, p-tolyl group, p-butylphenyl group, naphthyl group, etc., heterocyclic group (eg, tetrahydrofuryl group, 2-pyrrolidinone-1- Yl group, thienyl group, furyl group, pyridyl group, carbazolyl group, pyrrolyl group, indolyl group and the like), halogen atom (for example,
Fluorine atom, chlorine atom, bromine atom, etc.), vinyl group, trifluoromethyl group, alkoxy group (eg, methoxy group, ethoxy group, methoxyethoxy group, etc.), aryloxy group (eg, phenoxy group, p-tolyloxy group, etc.) ), A sulfonyl group (eg, a methanesulfonyl group, p
-Toluenesulfonyl group etc.), alkoxycarbonyl group (eg ethoxycarbonyl group, butoxycarbonyl group etc.), amino group (eg amino group, biscarboxymethylamino group etc.), acyl group (eg acetyl group,
Benzoyl group, etc.), ureido group (eg, ureido group,
3-methylureido group, 3-phenylureido group, etc.),
Examples thereof include thioureido group (eg, thioureido group, 3-methylthioureido group, etc.), alkylthio group (eg, methylthio, ethylthio group, etc.), arylthio group (eg, phenylthio group, etc.), hydroxy group, styryl group and the like.

These groups can be substituted with the groups mentioned in the description of the aliphatic group represented by R ₂₁ , and specific examples of the substituted alkyl group include, for example, 2-methoxyethyl group, 2-hydroxyethyl group, 3-ethoxycarbonylpropyl group,
Examples include 2-carbamoylethyl group, 2-methanesulfonylethyl group, 3-methanesulfonylaminopropyl group, benzyl group, phenethyl group, carboxymethyl group, carboxyethyl group, allyl group, 2-furylethyl group and the like. Specific examples of the substituted aryl group include, for example, p-carboxyphenyl group, p-N, N-dimethylaminophenyl group, p-morpholinophenyl group, p-methoxyphenyl group, 3,4-dimethoxyphenyl group. ,
Each group such as a 3,4-methylenedioxyphenyl group, a 3-chlorophenyl group, a p-nitrophenyl group and the like can be mentioned, and specific examples of the substituted heterocyclic group include, for example, a 5-chloro-2-pyridyl group, Examples thereof include 5-ethoxycarbonyl-2-pyridyl group and 5-carbamoyl-2-pyridyl group.

W ₂₁ and W ₂₂ , W ₂₃ and W ₂₄ , W ₃₁ and W ₃₂ , W
Examples of the condensed ring which can be formed by connecting ₃₃ and W ₃₄ to each other include a 5- or 6-membered saturated or unsaturated condensed carbocyclic ring. The condensed ring may have a substituent at any position, and examples of the substituent include the groups described above as the group capable of substituting the aliphatic group.

Examples of the halogen atom represented by V _{21 to} V ₂₉ and V _{31 to} V ₃₃ include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, and the amino group includes substituted and unsubstituted ones. , For example, an amino group, a dimethylamino group, a diphenylamino group, a methyl-phenylamino group, and the like, examples of the alkylthio group include, for example, a methylthio group, an ethylthio group, a benzylthio group, etc. Examples of the lower alkyl group include a substituted group, such as a phenylthio group and an m-fluorophenylthio group, and a lower alkyl group is a linear or branched group having 5 or less carbon atoms, specifically, a methyl group or an ethyl group. Base,
Examples thereof include a propyl group, a butyl group, a pentyl group and an isopropyl group. The lower alkoxy group is a group having 4 or less carbon atoms, and specific examples thereof include a methoxy group, an ethoxy group, a propoxy group and an iso-propoxy group, and the aryl group is a substituted or unsubstituted group. Including,
For example, phenyl group, 2-naphthyl group, 1-naphthyl group,
o-tolyl group, o-methoxyphenyl group, m-chlorophenyl group, m-bromophenyl group, p-tolyl group, p-
Examples include groups such as an ethoxyphenyl group, and examples of aryloxy groups include substituted and unsubstituted groups, and specific examples include groups such as phenoxy group, p-tolyloxy group, and m-carboxyphenyloxy group. The heterocyclic group includes substituted and unsubstituted groups, for example, 2-furyl group, 5-methyl-2-furyl group, 2-thienyl group, 2-imidazolyl group, 2-methyl-1-imidazolyl group, 4- Examples thereof include phenyl-2-thiazolyl group, 5-hydroxy-2-benzothiazolyl group, 2-pyridyl group and 1-pyrrolyl group. These groups include phenyl group, halogen atom,
Groups such as an alkoxy group and a hydroxyl group can be substituted.

Also, V ₂₁ and V ₂₃ , V ₂₂ and V ₂₄ , V ₂₃ and V ₂₅ , V ₂₄ and V ₂₆ , V ₂₅ and V ₂₇ , V ₂₆ and V ₂₈ , V ₂₇ and V
Examples of the 5-membered to 7-membered ring formed by bonding between ₂₉ and V ₃₁ and V ₃₃ include a cyclopentene ring, a cyclohexene ring, a cycloheptene ring, a decalin ring and the like. The lower alkyl group, lower alkoxy group and aryl group mentioned above can be substituted.

In the spectral sensitizing dyes represented by the above general formulas (1) and (2), when a group having a cation or anion charge is substituted, the charges in the molecule cancel each other. A counterion is formed with an equivalent amount of anion or cation. For example, in the ions necessary for offsetting the charges in the molecule represented by X ₂₁ and X ₃₁ , specific examples of the cation include a proton, an organic ammonium ion (eg, triethylammonium, triethanolammonium, pyridinium, etc.). Of each ion) and an inorganic cation (for example, each cation of lithium, sodium, potassium, etc.), and specific examples of the acid anion include, for example, halogen ion (for example, chlorine ion, bromide ion, iodine ion, etc.), p -Toluenesulfonate ion,
Perchlorate ion, boron tetrafluoride ion, sulfate ion,
Examples thereof include methylsulfate ion, ethylsulfate ion, methanesulfonate ion, trifluoromethanesulfonate ion, and hexafluorophosphate ion.

The typical compounds of the spectral sensitizing dyes represented by the above general formulas (1) and (2) are shown below, but the present invention is not limited to these compounds.

[0085]

[Chemical 2]

[0086]

[Chemical 3]

[0087]

[Chemical 4]

[0088]

[Chemical 5]

[0089]

[Chemical 6]

[0090]

[Chemical 7]

[0091]

[Chemical 8]

The infrared sensitizing dyes described above are, for example, The Chemistry of H by F.M.Harmer.
Volume 18 of eterocyclic Compounds,
The Cyanine Dyes and Rela
ted Compounds (A. Weissherg
er ed. Published by Interscience, NewY
ork 1964), JP-A-3-138638, JP-A-10-73900, JP-A-9-510022, US Pat. No. 2,734,900, British Patent 77.
It can be easily synthesized by the method described in US Pat. No. 4,779.

Although the spectral sensitizing dye may be used alone,
A combination of two or more sensitizing dyes can also be used.
When the sensitizing dyes are used alone or in combination, the total amount is 1 × 10 ^{−6 to} 5 × 1 per mol of silver halide.
It is contained in the silver halide emulsion in a proportion of 0 ^-3 mol, preferably 1 x 10 ^{-5 to} 2.5 x 10 ^-3 mol, and more preferably 4 x 10 ^-5 to 1 x 10 ^-3 mol. When two or more sensitizing dyes are used in combination, they can be contained in the silver halide emulsion in any proportion.

A combination of sensitizing dyes is often used especially for the purpose of supersensitization. Along with the sensitizing dye, a dye that does not itself have a spectral sensitizing effect or a substance that does not substantially absorb visible light and exhibits supersensitization may be included in the emulsion.

(Layer Structure) The photothermographic material of the present invention has at least one photosensitive layer on a support. Although only the photosensitive layer may be formed on the support, it is preferable to form at least one non-photosensitive layer on the photosensitive layer. A filter layer may be formed on the same side as or on the opposite side of the photosensitive layer in order to control the amount or wavelength distribution of light passing through the photosensitive layer, or the photosensitive layer may contain a dye or pigment. Good. As the dye, the compounds described in JP-A 8-201959 are preferred. The photosensitive layer may be composed of a plurality of layers, or a high-sensitivity layer and a low-sensitivity layer may be provided for adjusting gradation, and these layers may be combined. Various additives may be added to any of the photosensitive layer, the non-photosensitive layer or other forming 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.

(Coating) All coating solutions used for coating the photothermographic material of the present invention are preferably filtered before coating. In the filtration, it is preferable to pass a filter medium having an absolute filtration accuracy or a quasi-absolute filtration accuracy of 5 to 50 μm at least once.

Examples of the application of the photothermographic material of the present invention include a sequential multi-layer application method in which application and drying of each layer are repeated.
Roll coating methods such as reverse roll coating and gravure roll coating, blade coating, wire bar coating, die coating and the like are used. Also, before drying the already coated layer using multiple coaters, the following layers are applied to dry multiple layers at the same time, or slide coating, curtain coating, or an extrusion type die coater having multiple slits is used. A simultaneous multi-layer coating method in which the coating solutions of (1) and (2) are laminated and applied is also used. Of these, the latter is more preferable because it can prevent the occurrence of coating failure due to foreign substances brought in from the outside.
Further, when the simultaneous multi-layer coating method is used, in order to prevent mixing between layers, the viscosity of the coating solution of the uppermost layer is set to 0.1 Pa · s or more, and the viscosity of the coating solution of other layers is not changed. The viscosity is preferably 0.03 Pa · s or more.
Also, when the solid content dissolved in the coating liquid of each layer is laminated in liquid form with the adjacent layer, if it is hardly soluble or insoluble in the organic solvent of the adjacent layer, it will precipitate at the boundary surface and the coating film will be disturbed or turbid. Therefore, it is preferable that the organic solvent most contained in the coating liquid of each layer is the same type (the content of the organic solvent commonly contained in each coating liquid in each liquid is larger than that of the other organic solvent). .

Drying is preferably carried out as soon as possible after the multi-layer coating, and it is desirable to reach the drying step within 10 seconds in order to avoid inter-layer mixing due to flow, diffusion and density difference. As a drying method, a hot air drying method, an infrared drying method, or the like is used, and the hot air drying method is particularly preferable. The drying temperature at that time is preferably 30 to 100 ° C.

The photothermographic material of the present invention may be cut into a desired size immediately after coating and drying and then packaged, or may be wound into a roll and temporarily stored before cutting and packaging. The winding method is not particularly limited, but winding by tension control is generally used.

(Exposure) The heat-developable photosensitive material of the present invention is exposed to argon ion laser (488 nm) and He-N.
e laser (633 nm), red semiconductor laser (67
0 nm), infrared semiconductor laser (780 nm, 820 n
m) and the like are preferably used, but an infrared semiconductor laser is more preferably used from the viewpoint that the laser power is high and the photosensitive material can be made transparent.

In the present invention, it is preferable to use a laser scanning exposure machine in which the angle formed by the scanning laser light and the exposed surface of the photosensitive material is not substantially perpendicular.

Here, the phrase "substantially not becoming vertical" means that the angle is the most vertical during laser scanning, preferably 55 degrees or more and 88 degrees or less, more preferably 60 degrees or more and 86 degrees or less, and further preferably Means 65 degrees or more and 84 degrees or less, and most preferably 70 degrees or more and 82 degrees or less.

The diameter of the beam spot on the exposed surface of the photosensitive material when the laser light is scanned on the photosensitive material is preferably 200 μm or less, more preferably 100 μm or less. It is preferable that the spot diameter is smaller because the angle of deviation of the laser incident angle from the vertical can be reduced. The lower limit of the beam spot diameter is 10 μm. By performing such laser scanning exposure, it is possible to reduce image quality deterioration due to reflected light such as occurrence of interference fringe-like unevenness.

The exposure in the present invention is also preferably carried out by using a laser scanning exposure machine which emits scanning laser light having a longitudinal multi-direction. Image quality deterioration such as occurrence of interference fringe-like unevenness is reduced as compared with the vertical single mode scanning laser light. In order to make the vertical multi, it is preferable to use a method of returning light by multiplexing, applying a high frequency superposition, or the like. The vertical multi means that the exposure wavelength is not single, and the distribution of the exposure wavelength is usually 5 nm or more, preferably 10 nm or more. There is no particular upper limit on the distribution of exposure wavelength,
Usually, it is about 60 nm.

(Heat Development) Although the photothermographic material of the present invention is stable at room temperature, it is developed by heating to high temperature after exposure. The heating temperature is preferably 80 ° C. or higher and 200 ° C. or lower, and more preferably 100 ° C. or higher and 150 ° C. or lower. If the heating temperature is 80 ° C or lower, sufficient image density cannot be obtained in a short time, and if the heating temperature is 200 ° C or higher, the binder melts,
Not only the image itself, such as transfer to the roller, but also the transportability and developing machine are adversely affected. By heating, a silver image is generated by a redox reaction between an organic silver salt (which functions as an oxidizing agent) and a reducing agent. This reaction process proceeds without supplying a treatment liquid such as water from the outside.

[0106]

The present invention is described in detail below with reference to examples, but the present invention is not limited to these. Unless otherwise specified, “%” in the examples means “mass%”. or,
The “mol / L concentration” is represented by “M”. <Example 1> (Preparation of photosensitive silver halide emulsion) A1 Phenylcarbamoyl gelatin 88.3 g Compound (A) (10% methanol solution) 10 ml Potassium bromide 0.32 g B1 0.67 M silver nitrate aqueous solution finished with water to 5429 ml 2635 ml C1 potassium bromide 51.55 g potassium iodide 1.47 g finished with water to 660 ml D1 potassium bromide 154.9 g potassium iodide 4.41 g iridium chloride 0.0093 g potassium ferrocyanide 0.0081 g finished with water 1980 ml E1 4M aqueous potassium bromide solution Silver potential control amount F1 56% aqueous acetic acid solution 16.0 ml G1 anhydrous sodium carbonate 1.72 g Compound (A) finished with water to 151 ml: HO (CH ₂ CH ₂ O) _n- [CH (CH ₃ ) CH ₂ O] <sub>17
- (CH 2 CH 2 O)</sub> m Hm + n = 5~7 B No. 58-58288, a solution (A1) with a mixing and stirring machine shown in Nos. 58-58289 solution (B1)
1/4 amount and the total amount of the solution (C1) were 39 ° C., pAg8.
While controlling at 09, it was added for 4 minutes and 45 seconds by the simultaneous mixing method to perform nucleation. After 7 minutes, the solution (B
The rest of 1) and the total amount of the solution (D1) were heated at a temperature of 45 ° C., p
While controlling to Ag 8.09, it was added over 14 minutes and 15 seconds by the double-blending method. During the mixing, the pH of the reaction solution was 5.
It was 6.

After stirring for 5 minutes, the temperature was lowered to 40 ° C., the whole amount of the solution (F1) was added, and the silver halide emulsion was precipitated. Remove the supernatant, leaving 2000 ml of sedimentation,
After adding 10 L of water and stirring, the silver halide was precipitated again. The supernatant was removed, leaving 1500 ml of the sedimented portion, 10 L of water was further added, and after stirring, the silver halide was precipitated. After removing the supernatant liquid, leaving 1500 ml of the sedimented portion, the solution (G1) was added, the temperature was raised to 60 ° C., and the mixture was further stirred for 120 minutes. Finally, the pH was adjusted to 5.8, and water was added so that the amount was 1161 g per mol of silver.

This emulsion has an average grain size of 0.048 μm.
m, variation coefficient of particle size 12%, [100] plane ratio 9
It was 2% of cubic silver iodobromide grains.

(Preparation of powder non-photosensitive organic silver salt 1) 472
130.8 g of behenic acid and 6 of arachidic acid in 0 ml of pure water.
7.7 g, stearic acid 43.6 g, palmitic acid 2.
3 g was melted at 80 ° C. Next, 540.2 ml of a 1.5 M aqueous sodium hydroxide solution was added, 6.9 ml of concentrated nitric acid was added, and then the mixture was cooled to 55 ° C. to obtain a sodium organic acid solution. While keeping the temperature of the above-mentioned organic acid sodium salt solution at 55 ° C., 45.3 g of the above-mentioned photosensitive silver halide emulsion and 450 ml of pure water were added and stirred for 5 minutes.

Next, 702.6 ml of 1M silver nitrate solution was added to 2 parts.
The mixture was added over a period of 10 minutes and stirred for 10 minutes to obtain a non-photosensitive organic silver salt dispersion. After that, the obtained non-photosensitive organic silver salt dispersion is transferred to a water washing container, deionized water is added and stirred, and the mixture is allowed to stand to float-separate the non-photosensitive organic silver salt dispersion, and the lower water-soluble salts are added. Was removed. After that, the conductivity of drainage is 2 μS /
After repeated washing with deionized water and drainage until centimeters, centrifugal dehydration was carried out, and drying with a warm air circulation dryer at 40 ° C until there was no loss of mass, trace amounts of photosensitive silver halide were mixed. A powder non-photosensitive organic silver salt 1 was obtained.

When the organic acid precipitation temperature and the organic acid dissolution temperature were measured with the composition of the organic acid used for the preparation, the precipitation temperature was 4
The melting point was 20 ° C.

(Preparation of powder non-photosensitive organic silver salt 2) Except for using behenic acid 212.6 g and stearic acid 31.8 g in the preparation process of powder non-photosensitive organic silver salt 1, exactly the same. To obtain a powder non-photosensitive organic silver salt 2.

In the organic acid composition used for the preparation, the organic acid precipitation temperature was 12 ° C and the organic acid dissolution temperature was 29 ° C.

(Preparation of powder non-photosensitive organic silver salt 3) In the step of preparing powder non-photosensitive organic silver salt 1, organic acids used were 97.8 g of behenic acid, 122.2 g of arachidic acid and 24.4 g of stearic acid. Except for the above, the powder non-photosensitive organic silver salt 3 was obtained in exactly the same manner.

With the organic acid composition used for the preparation, the organic acid precipitation temperature was 6 ° C., and the organic acid dissolution temperature was 21 ° C.

(Preparation of preliminary dispersion liquid) Polyvinyl butyral powder (Sekisui Chemical Co., Ltd., S-REC BL-5) 14.
Dissolve 57g in MEK1457g, VMA-GETZ
Mann Dissolver DISPERMAT CA-4
Each of Preliminary Dispersions 1 to 3 was prepared by gradually adding 500 g of each powdery non-photosensitive organic silver salt obtained by mixing a slight amount of the photosensitive silver halide obtained by stirring with 0M type and thoroughly mixing them. Was prepared.

(Preparation of Photosensitive Emulsion Dispersion) Preliminary Dispersion 1
The media type disperser DISPERMAT SL-C12EX (filled with 80% of the internal volume of zirconia beads having a diameter of 0.5 mm (Toray's Treceram) so that the residence time in the mill for 10 minutes for each of 3 to 3 will be 10 minutes ( VM
A-GETZMANN), and the peripheral speed of the mill is 13 m.
/ S to disperse the photosensitive emulsion dispersions 1 to 3
Was prepared.

(Preparation of stabilizer solution) 1.0 g of stabilizer 1,
0.31 g of potassium acetate was dissolved in 4.97 g of methanol to prepare a stabilizer solution.

(Preparation of Infrared Sensitizing Dye Solution) 19.2 mg of infrared sensitizing dye (Exemplified Compound 1-3), 1.488 g of 2
-Chloro-benzoic acid, 2.779 g of stabilizers 2 and 36
An infrared sensitizing dye solution was prepared by dissolving 5 mg of 5-methyl-2-mercaptobenzimidazole in 31.3 ml of MEK in the dark.

(Preparation of Supersensitizer Solution) 50.1 mg of Supersensitizer 1 was dissolved in 8.8 g of methanol to prepare a supersensitizer solution.

(Preparation of Additive Solution a) 27.98 g of Developer 1, 1.54 g of 4-methylphthalic acid and 0.48 g of Infrared Dye 1 were dissolved in 110 g of MEK to prepare Additive Solution a.

(Preparation of Additive Solution b) 3.56 g of antifoggant 2, 3.43 g of phthalazine was dissolved in 40.9 g of MEK to prepare Additive Solution b.

(Preparation of Photosensitive Layer Coating Solution) 50 g of each of Photosensitive Emulsion Dispersions 1 to 3 and 15.11 g of MEK were kept at the initial temperature shown in Table 1 with stirring to prevent fog 1
(10% methanol solution) (390 μl) was added, and the mixture was stirred for 1 hour. Further, 494 μl of calcium bromide (10% methanol solution) as a halogen donor was added and stirred for 20 minutes. Subsequently, 167 mg of the stabilizer solution was added and
After stirring for a minute, after reaching the dye adsorption temperature shown in Table 1,
2.622 g of infrared sensitizing dye solution was added and stirred for 1 hour.

Then, the temperature was lowered to 13 ° C. and the mixture was further stirred for 25 minutes. While maintaining the temperature at 13 ° C, 0.70 g of a supersensitizer solution was added and stirred for 5 minutes, and then polyvinyl butyral (Sekisui Chemical Co., Ltd. S-REC BL-5) 1
After 3.31 g was added and stirred for 30 minutes, 1.084 g of tetrachlorophthalic acid (9.4 mass% MEK solution) was added and stirred for 15 minutes. While continuing to stir 1
2.43 g of additive liquid a, 1.6 ml of Desmodur
N3300 / Mohbay's aliphatic isocyanate (1
(0% MEK solution), 4.37 g of the additive liquid b was sequentially added and stirred to obtain a photosensitive layer coating liquid.

There are 48 kinds of photosensitive layer coating solutions in total. That is, 16 kinds of photosensitive emulsion dispersion 1 (Sample N in Table 1
o. 1-1 to 1-16), 16 kinds of photosensitive emulsion dispersion 2 (Sample No. 2-1 to 2-16 in Table 1), 16 kinds of photosensitive emulsion dispersion 3 (Sample No. 1 of Table 1). 3-1 to 3-1
6).

[0126]

[Table 1]

(Preparation of Matting Agent Dispersion) Cellulose Acetate Butyrate (Eastman Chemical)
Company, 7.5 g of CAB171-15) to MEK42.5
g of calcium carbonate (Specia)
Light Minerals, Super-Pfle
x200) (5 g) was added, and the resulting mixture was dispersed with a dissolver type homogenizer at 8000 rpm for 30 minutes to prepare a matting agent dispersion liquid.

(Preparation of Surface Protective Layer Coating Solution) MEK865
g of cellulose acetate butyrate (Eastman Chemical Company, CAB171-
15): 96 g, polymethylmethacrylic acid (Rohm & Haas Company, Paraloid A-21): 4.5 g, vinyl sulfone compound (HD-1): 1.5 g, benzotriazole: 1.0 g, F-based activator ( Asahi Glass Company, Surflon KH
40): 1.0 g, was added and dissolved. Next, 30 g of the matting agent dispersion liquid was added and stirred to prepare a surface protective layer coating liquid.

[0129]

[Chemical 9]

(Coating on Photosensitive Layer Side) Photosensitive layer coating liquid 1 (Table 1)
Sample No. 1-1) and the viscosity of the surface protective layer coating liquid are adjusted to 0.228 Pa.
s, 0.184 Pa · s, quasi-absolute filtration accuracy 20 μm
After being filtered through the above filter, the mixture was discharged from the slit of the extrusion type die coater, laminated, and simultaneously multilayer-coated on the support. Eight seconds later, after drying for 5 minutes using hot air having a drying temperature of 75 ° C. and a dew point temperature of 10 ° C., an ambient temperature and humidity of 23 ° C. 50% RH and a tension of 196 N / m (20 kg / m)
A photothermographic material 1 (Sample No. 1-1 in Table 2) was produced by winding the sample into a roll. The amount of silver coated on the photosensitive layer of the obtained heat-developable photosensitive material was 1.9 g / m ² , and the surface protective layer had a dry film thickness of 2.5 μm.

Similarly, the photosensitive layer coating solution 2 (Sample No. 1-2 in Table 1) and subsequent coatings were applied to produce the photothermographic materials 2 (Sample No. 1-2 in Table 2) and later, respectively. did. There are a total of 48 types of photothermographic materials. That is, the sample No. 1-1 to Sample No. Each of the photosensitive layer coating solutions of Nos. 1 to 16 has the sample No. 1-1 to sample N
o. Corresponding to the photothermographic material of No. 1-16, sample N of Table 1
o. 2-1 to Sample No. Each of the photosensitive layer coating solutions of Nos. 2-16 is the sample No. 2 in Table 2. 2-1 to Sample No. Sample No. 1 in Table 1 corresponding to the photothermographic material of No. 2-16. 3-1 to Sample No. Each of the photosensitive layer coating solutions of Nos. 3-16 is sample N in Table 2.
o. 3-1 to Sample No. 3-16 corresponds to the photothermographic material.

(Exposure and Development Treatment) From the emulsion surface side of the photothermographic material prepared as described above, an exposure machine using a semiconductor laser in the longitudinal multimode having a wavelength of 800 nm to 820 nm as a light emitting source by high frequency superposition was used. Exposure by laser scanning was applied. At this time, an image was formed by setting the angle between the exposed surface of the photothermographic material and the exposure laser beam at 75 degrees. (Note that an image with less unevenness and unexpectedly good sharpness was obtained compared to the case where the angle was 90 degrees.) Thereafter, the photothermographic material was developed using an automatic processor having a heat drum. Heat development treatment was performed at 110 ° C. for 15 seconds so that the protective layer was in contact with the drum surface. At that time, exposure and development were performed in a room where the humidity was adjusted to 23 ° C. and 50% RH. The obtained image was evaluated with a densitometer. The measurement results are evaluated by sensitivity (the reciprocal of the ratio of the exposure amount that gives a density 1.0 higher than that of the unexposed portion) and fog, and shown in Table 2 as a relative value with the sensitivity of the photothermographic material 1 being 100. It was

(Evaluation of image storability) Two samples treated in the same manner as in the sensitometric evaluation, one sample at 25 ° C. and 55 samples.
Store at 7% at 25 ° C, 55% for 7 days protected from light.
After exposing to natural light for a day, the density of the fog portion of both was measured. The results are shown in Table 2.

Increase in fog = fog when exposed to natural light-fog when stored with light shielded to evaluate image storability.

(Evaluation of image quality) Density of developed sample 1.0
The part was observed under an optical microscope manufactured by Mitutoyo under a transmission mode at 100 times, and deterioration of image quality due to white spots, aggregates and the like was evaluated according to the following four grades. The results are shown in Table 2. 4: Good image quality with little white spots and aggregates 3: Some white spots and aggregates, but no problem for the product Image quality 2: White spots, aggregates present : Many white spots and aggregates cannot be used as products

[0136]

[Table 2]

From Table 2, it can be seen that the samples according to the present invention have high covering power, high sensitivity and little fog, and the storability of silver images after development and the silver tone and image quality are remarkably improved.

[0138]

According to the present invention, a method for producing a photothermographic material having high covering power, high sensitivity, less fog, improved silver image storability after development, and improved silver color tone and image quality, and a photothermographic material. It was possible to provide an image recording method and an image forming method.

Claims (6)

[Claims] 1. A non-photosensitive organic silver salt, a photosensitive silver halide, a reducing agent capable of reducing silver ions of the non-photosensitive organic silver salt to silver when activated by heat, a binder, and a binder. In the method for producing a photothermographic material containing a cross-linking agent, the non-photosensitive organic silver salt and a halogen supplier at a temperature not lower than the organic acid precipitation temperature of the organic acid constituting the non-photosensitive organic silver salt and lower than the organic acid dissolution temperature. And a step of causing a sensitizing dye to be adsorbed on the photosensitive silver halide at a temperature of dissolving an organic acid or above, and a method for producing a photothermographic material. 2. The temperature difference between the step of reacting a non-photosensitive organic silver salt and a halogen donor and the step of adsorbing a sensitizing dye to a photosensitive silver halide is 5 ° C. or more. 1. The method for producing a photothermographic material according to 1. 3. A photothermographic material obtained by the manufacturing method according to claim 1. 4. An image recording method, wherein the photothermographic material according to claim 3 is exposed by a laser exposure machine. 5. The photothermographic material according to claim 3,
An image forming method, which comprises developing by heating at a temperature of not less than 200 ° C. and not more than 200 ° C. 6. An image forming method, which comprises developing the photothermographic material exposed by the image recording method according to claim 4 by heating at a temperature of 80 ° C. or higher and 200 ° C. or lower.