JP2003241336A - 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 heat-developable photosensitive material having high sensitivity, low fog and good image preservability according to conditions during production of silver halide grains as a photocatalyst and an organic silver salt as a reducible silver salt and to provide an image recording method and an imaging method for the heat-developable photosensitive material. <P>SOLUTION: In a method for producing a heat-developable photosensitive material comprising at least a non-photosensitive organic silver salt, a photosensitive silver halide, a reducing agent capable of reducing the silver ion of the organic silver salt on activation with heat, a binder and a crosslinking agent for the binder, at least one transition metal selected from the groups 6-11 elements of a periodic table of the elements is added to a step after the organic silver salt is formed. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photothermographic material for forming an image by heat development, which has high sensitivity, little fogging, and good image storability, and a method for producing the same. The present invention relates to 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 associated with 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, which enables efficient exposure by a laser imagesetter or a laser imager and can form a clear black image with high resolution. As this technique, for example, US Pat. Nos. 3,152,904 and 3,487,
075 and D.I. "Dry Silver Pho" by Morgan
topographic materials ”(Han
db of of Imaging Material
s, Marcel Dekker, Inc. 48th
, 1991) and the like are well known. Since these photosensitive materials are usually developed at a temperature of 80 ° C. or higher, they are heat-developable photosensitive materials (hereinafter also referred to as photosensitive materials).
It is called.

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 that is softened by heat in order to form an image by dissolving physical development in the layer by heat, and a layer is formed in this layer with an organic silver salt as a silver ion source and a photosensitive 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 as a built-in silver ion source reacts with the reducing agent to develop the image. Progresses to form an image. It is characterized in that development proceeds without supplying reagents, water, etc. 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.

This photothermographic material is exposed by a laser imager or a laser imagesetter. Since the exposure by the laser is a high-intensity short-time exposure, desensitization due to a high-illuminance failure is a problem. To solve this problem, it is widely known that a photosensitive silver halide grain contained in a photothermographic material contains a transition metal complex such as iridium.

On the other hand, when these heat-developable photosensitive materials are stored as they are unused, the problems such as fog, sensitivity and gradation change, and the problem that fog and color tone change even after storage after development. However, there are proposals for countermeasures, but they are not practically sufficient, and further improvements have been desired.

[0006]

The object of the present invention relates to a method for producing a photothermographic material, which has a high sensitivity depending on the production conditions of a silver halide grain which is a photocatalyst and an organic silver salt which is a reducible silver salt. And to provide a photothermographic material having low fog and good image storability, and further to provide an image recording method and an image forming method for the photothermographic material.

[0007]

Means for Solving the Problems The above-mentioned problems have been achieved by the following means.

1) At least a non-photosensitive organic silver salt, a photosensitive silver halide, a reducing agent capable of reducing silver ions of the organic silver salt to silver when activated by heat, a binder, and crosslinking of the binder. In the method for producing a photothermographic material containing an agent, at least one transition metal selected from the elements of Groups 6 to 11 of the periodic table of elements is added to the step after the organic silver salt is formed. A method for producing a photothermographic material, which is characterized.

2) At least a non-photosensitive organic silver salt, a photosensitive silver halide, a reducing agent capable of reducing silver ions of the organic silver salt to silver when activated by heat, a binder, and crosslinking of the binder. In the method for producing a photothermographic material containing an agent, a photosensitive material obtained by doping at least one transition metal selected from the elements of Groups 6 to 11 of the periodic table in the step after the organic silver salt is formed. A method for producing a photothermographic material, which comprises adding silver halide.

3) At least a non-photosensitive organic silver salt, a photosensitive silver halide, a reducing agent capable of reducing silver ions of the organic silver salt to silver when activated by heat, a binder, and crosslinking of the binder. In the method for producing a photothermographic material containing an agent, the organic silver salt is formed in the presence of a photosensitive silver halide which is not doped with a transition metal selected from elements of Groups 6 to 11 of the periodic table of elements. And reacting the organic silver salt with a halogen supplier in an organic solvent in the presence of at least one transition metal to further form a photosensitive silver halide. Method.

4) The photothermographic material according to any one of 1) to 3) above, wherein the average equivalent silver particle diameter of the photosensitive silver halide is 0.03 μm or more and 0.20 μm or less. Material manufacturing method.

5) The transition metal is a metal selected from iron, cobalt, ruthenium, rhodium, rhenium, osmium or iridium, and the above 1) to 1)
4. The method for producing a photothermographic material according to any one of 4).

6) A photothermographic material obtained by the manufacturing method described in any one of 1) to 5) above.

7) The photothermographic material as described in 6) above, which is spectrally sensitized to 720 to 1000 nm.

8) An image recording method, which comprises exposing the photothermographic material described in 6) or 7) above with a laser exposure machine.

9) An image forming method, which comprises developing the photothermographic material according to 6) or 7) by heating at a temperature of 80 ° C. or higher and 200 ° C. or lower. Hereinafter, the present invention will be described in detail.

The photosensitive silver halide according to the present invention will be described. Photosensitive silver halide functions as an optical sensor and suppresses white turbidity after image formation.
Further, in order to obtain good image quality, those having a small particle size are preferable. The average particle size is preferably 0.03 to 0.2 μm, particularly preferably 0.04 to 0.08 μm. The shape of the silver halide is not particularly limited, and there are cubic and octahedral so-called normal crystals and non-normal crystals such as spherical particles, rod-shaped particles and tabular particles. The silver halide composition is also not particularly limited and may be any of silver chloride, silver chlorobromide, silver chloroiodobromide, silver bromide, silver iodobromide and silver iodide. The amount of silver halide is preferably 3 to 7%, and more preferably 5 to 7% in terms of silver ratio with respect to the non-photosensitive organic silver salt described below.

The method for preparing a silver halide emulsion containing the photosensitive silver halide grains according to the present invention is described in P. Gl
afkides Chimie et Physiqu
ePhotographique (Paul Montt)
el, 1967), G.I. F. Duffin P
photographic Emulsion Chem
istry (published by The Focal Press, 19
66), V.I. L. Zelikman et al M
aking and Coating Photogr
aphic Emulsion (The Focal
Press, 1964) and the like, and these can be used to prepare the silver halide emulsion used in the present invention.

That is, any of an acidic method, a neutral method, an ammonia method and the like may be used, and as a method for reacting the soluble silver salt and the soluble halogen salt, any of a one-sided mixing method, a simultaneous mixing method and a combination thereof may be used. You may use. Typically,
A silver halide emulsion is prepared by mixing an aqueous solution of silver salt and an aqueous solution of halide in a protective colloid solution (a hydrophilic colloid such as gelatin is used) serving as a reaction mother liquor to perform nucleation and crystal growth. The double jet method is generally used as a method for adding the aqueous solution or the aqueous silver salt solution.

Among them, a controlled double jet method is typical in which the respective components are mixed while controlling pAg and pH to carry out the nucleation and crystal growth. This includes various variations such as a method of preparing seed particles (nucleation) and then performing this growth in two steps such as the same conditions or different conditions (crystal growth or ripening). The point is to control the crystal habit and size in various ways by defining the mixing conditions of the silver salt aqueous solution and the halide aqueous solution in the mixing step in the protective colloid aqueous solution, which is well known in the art. .

Following these mixing steps, a desalting step for removing excess salts from the emulsion prepared is carried out. The desalting step is a flocculation method in which a coagulant is added to the prepared silver halide emulsion to coagulate and precipitate silver halide grains together with gelatin which is a protective colloid, and this is separated from a supernatant containing salts. well known. The supernatant liquid is removed by decantation, and dissolution, flocculation and decantation are repeated in order to remove excess salts contained in the gelatin coagulate containing the silver halide grains which have been aggregated and precipitated. Also, a method of removing soluble salts by an ultrafiltration method is well known. This is a method of removing unnecessary salts with low molecular weight by using an ultrafiltration membrane and using a synthetic membrane that does not allow permeation of large particles such as silver halide grains and gelatin and molecules with large molecular weight. .

The photosensitive silver halide prepared by the various methods described above is chemically sensitized with, for example, a sulfur-containing compound, a gold compound, a platinum compound, a palladium compound, a silver compound, a tin compound, a chromium compound or a combination thereof. can do. For the method and procedure of this chemical sensitization, see, for example, US Pat. No. 4,036,650.
No., British Patent No. 1,518,850, JP-A-51-2
No. 2430, No. 51-78319, No. 51-8112
No. 4 is described. Further, when a part of the organic silver salt is converted into a photosensitive silver halide by the silver halide-forming component, as described in U.S. Pat. No. 3,980,482, a low sensitization is required to achieve sensitization. An amide compound having a molecular weight may coexist.

In the present invention, the organic silver salt is a reducible silver source, and is a silver salt of an organic acid or a heteroorganic acid, particularly a long-chain silver salt having 10 to 30 carbon atoms, preferably 15 to 2 carbon atoms.
5) Silver salts of aliphatic carboxylic acids and nitrogen-containing heterocyclic compounds are preferred. An organic or inorganic complex in which the ligand has a value of 4.0 to 10.0 as a total stability constant with respect to silver ions is also preferable. Examples of these suitable silver salts include R
essearch Disclosure 17029
And 29963, and includes the following.

Silver salts of organic acids such as gallic acid, oxalic acid,
Silver salts such as behenic acid, stearic acid, arachidic acid, palmitic acid and lauric acid. Silver carboxyalkyl thiourea salts, for example, silver salts such as 1- (3-carboxypropyl) thiourea, 1- (3-carboxypropyl) -3,3-dimethylthiourea, aldehydes and hydroxy-substituted aromatic carboxylic acids Silver salts or complexes of polymer reaction products, for example, aldehydes (formaldehyde, acetaldehyde, butyraldehyde, etc.), hydroxy-substituted acids (eg salicylic acid, benzoic acid, 3,5-dihydroxybenzoic acid, 5,5-thiodisalicylic acid) ) A silver salt or complex of a reaction product, a silver salt or a complex of thioenes such as 3- (2-carboxyethyl) -4-hydroxymethyl-4-thiazoline-2-thioene, and 3-carboxymethyl-4. -Silver salts or complexes of thiazoline-2-thioene, imidazole, pyrazole, urazo , 1,
Complex or salt of nitric acid and silver selected from 2,4-thiazole and 1H-tetrazole, 3-amino-5-benzylthio-1,2,4-triazole and benzotriazole, saccharin, 5-chlorosalicylaldoxime Etc. and silver salts of mercaptides. Among these,
Preferred silver salts are silver behenate, silver arachidate or silver stearate.

The organic silver salt compound can be obtained by mixing a water-soluble silver compound and a compound that forms a complex with silver. The forward mixing method, the reverse mixing method, the simultaneous mixing method, and JP-A-9-12764.
The controlled double jet method described in No. 3 is preferably used. For example, by adding an alkali metal salt (for example, sodium hydroxide, potassium hydroxide, etc.) to an organic acid, an organic acid alkali metal salt soap (for example,
Sodium behenate, sodium arachidate, etc.) are prepared, and then the soap and silver nitrate are added by a control double jet to prepare organic silver salt crystals. At that time, silver halide grains may be mixed.

In the present invention, the organic silver salt has an average particle size of 2
It is preferably μm or less and monodisperse. The average particle size of the organic silver salt is, for example, when the particles of the organic silver salt are spherical, rod-shaped, or tabular particles, the diameter when considering a sphere equivalent to the volume of the organic silver salt particles. Say. The average particle size is preferably 0.05 to 1.5 μm, particularly 0.05 to
1.0 μm is preferable. 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 organic silver salt preferably have 60% or more of the total organic silver.
In the present invention, the tabular grains have an aspect ratio (abbreviated as AR) represented by the following formula, which is a ratio of average grain size to thickness of 3
The above is said.

AR = average particle diameter (μm) / thickness (μm) In order to form the organic silver into these shapes, the organic silver crystals are obtained by dispersing and pulverizing a binder, a surfactant and the like in a ball mill or the like. To be 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 silver halide and organic silver salt is not less than 0.5 g and not more than 2.2 g per m ² in terms of silver amount. It is preferable. 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.

In the present invention, at least one metal ion belonging to Groups 6 to 11 of the periodic table is added to the step after the organic silver salt is formed. The above metals include W, Fe, Co, Ni, Cu, R
u, Rh, Pd, Re, Os, Ir, Pt and Au are preferable, but Fe, Co, Ru, Rh and R are particularly preferable.
e, Os and Ir. The effect of the present invention can be obtained by adding these metal ions in the form of a metal complex or a metal complex ion.

The position of addition may be any position after the organic silver salt is formed, and may be any position after desalting after the formation of the organic silver salt and before coating. It may be added all at once, or may be added in multiple portions. Further, these metal ions, metal complexes or metal complex ions may be of one type, or two or more types of the same metal and different metals may be used in combination. As these metal complexes or metal complex ions,
A hexacoordinated metal complex represented by the following general formula is preferable.

[0032] Formula [ML _6] ^m wherein the transition metal M is selected from 6-11 group elements of the periodic table, L is a ligand, 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, tellurocyanates, azides and aco. Examples include ligands, nitrosyl, thionitrosyl, and the like, with preference given to ako, nitrosyl, thionitrosyl, and the like. 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.

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) 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-Since these metal ions can be introduced into the silver halide in the form of a metal complex or a metal complex ion, at least one of these metal ions was doped. The effect of the present invention can be obtained by adding the photosensitive silver halide in the step after the formation of the organic silver salt.

When these metal ions are introduced into the photosensitive silver halide, it is preferable that a metal complex or a metal complex ion is added at the time of forming silver halide grains and incorporated into the silver halide grains. It may be added at any stage before or after the preparation of grains, that is, nucleation, growth, physical ripening, and chemical sensitization, but it is particularly preferable to add at the stage of nucleation, growth, and physical ripening, and further nucleation Preferably, it is added at the growth stage, most preferably at the nucleation stage.

Upon addition, the silver halide grains may be added dividedly over several times, and may be incorporated uniformly in the silver halide grains.
-306236, 3-167545, 4-76
No. 534, No. 6-110146, No. 5-273683.
As described in the publication No., etc., the particles may be contained with a distribution. Preferably, it can have a distribution inside the particles.

These metal compounds can be dissolved in water or a suitable organic solvent (for example, alcohols, ethers, glycols, ketones, esters, amides) and added. A method of adding an aqueous solution of a compound powder or an aqueous solution in which a metal compound and NaCl or KCl are dissolved 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 Is added as a third aqueous solution when they are simultaneously mixed, a method of preparing silver halide grains by a three-liquid simultaneous mixing method, a method of charging a necessary amount of an aqueous solution of a metal compound into a reaction vessel during grain formation, or 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 the 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 an aqueous solution of the metal compound may be added to the reaction vessel immediately after the formation of the particles, during or during the physical ripening or at the end of the chemical ripening.

Further, an organic silver salt is formed in the presence of a photosensitive silver halide which is not doped with the transition metal, and the organic silver salt and a halogen donor are mixed with each other in the presence of at least one transition metal. The effect of the present invention can be obtained even if the reaction is carried out in a silver salt to further form silver halide.

Examples of halogen donors include organic solvents,
In particular, an inorganic halogen compound or an organic halogen compound soluble in a polar organic solvent or a polar organic solvent containing water is included. The inorganic halogen compound has a general formula MX _n
The compound represented by can be mentioned. However, in the formula M
Is a hydrogen atom or a metal atom (for example, strontium,
Cadmium, zinc, sodium, barium, cesium,
Calcium, iron, nickel, magnesium, potassium,
Aluminum, antimony, gold, cobalt, mercury, lead,
Beryllium, lithium, indium, iridium, rhodium, palladium, platinum, bismuth, etc.), X represents a chlorine atom, a bromine atom and an iodine atom, and n represents a valence of each cation. As the inorganic halogen compound, a halogen-containing metal complex such as K ₂ PtCl ₆ , K ₂ PtBr ₆ ,
HAuCl ₄ , (NH ₄ ) ₃ RuCl ₆ , K ₃ PhCl _{6 and the} like can be mentioned.

As typical compounds of the organic halogen compound, N-bromosuccinimide, N-bromotetrafluorosuccinimide, N-bromophthalimide, N-bromoglutarimide, N-bromoacetamide, N-
Examples thereof include bromacetanilide, N-bromobenzenesulfonylanilide, N-bromobenzamide, α-bromoacetophenone, α-chloroacetophenone, α-bromomethylsulfonylbenzene and α-bromotoluene.

Further, onium halide compounds are also useful as halogen donors, and specific examples thereof include ammonium bromide, trimethylphenylammonium chloride, trimethylbenzylammonium bromide, trimethylsulfonyl chloride and the like.

The content of metal ion, metal complex or metal complex ion is generally 1 × 10 ^-9 to 1 × 10 ^-2 mol per mol of silver halide, and preferably 1 × 10 9. ^-8 to 1 × 10 ^-4 mol.

As the organic silver salt of the present invention, tabular organic silver salt particles having an aspect ratio of 3 or more can be used. The tabular organic silver salt particles are preferably preliminarily dispersed with a binder, a surfactant and the like, if necessary, and then dispersed and pulverized by a media disperser or a high pressure homogenizer. 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.

Further, as the above-mentioned media disperser, a rolling mill such as a ball mill, a planetary ball mill, a vibrating ball mill, a bead mill which is a medium stirring mill, an attritor,
It is possible to use other basket mills,
As the high-pressure homogenizer, various types such as a type that collides with a wall or a plug, a type that divides a plurality of liquids and then collides liquids at high speed, a type that allows a liquid to pass through a thin orifice, and the like can be used.

Examples of the ceramics used for the ceramic beads used when the media are dispersed 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 of less generation of impurities due to friction with beads or a disperser during dispersion.

In the devices used for dispersing the tabular organic silver salt particles, ceramics such as zirconia, alumina, silicon nitride, boron nitride, or diamond is used as the material of the member with which the organic silver salt particles come into contact. 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 organic silver salt, and it is preferable that the liquid temperature does not exceed 45 ° C. from the preliminary dispersion to the main dispersion. Further, as preferable operating conditions for the main dispersion, for example, when a high-pressure homogenizer is used as a dispersing means, 29.42 to 98.06 MPa, and the number of times of operation is preferably 2 or more.
When a 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 beads or members, and can be 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.

Examples of the reducing agent used in the photothermographic material of the present invention include generally known reducing agents such as phenols, polyphenols having two or more phenol groups, naphthols and bisnaphthols. Two
Polyhydroxybenzenes having two or more hydroxyl groups, 2
Polyhydroxynaphthalene having at least one hydroxyl group,
Ascorbic acids, 3-pyrazolidones, pyrazoline-
5-ones, pyrazolines, phenylenediamines, hydroxylamines, hydroquinone monoethers,
There are hydrooxamic acids, hydrazides, amidoximes, N-hydroxyureas, and the like. More specifically, for example, US Pat. Nos. 3,615,533 and 3,67.
9,426, 3,672,904, 3,75
1,252, 3,782,949, 3,80
No. 1,321, No. 3,794,488, No. 3,89
No. 3,863, No. 3,887,376, No. 3,77
0,448, 3,819,382, 3,77
3,512, 3,839,048, 3,88
No. 7,378, No. 4,009,039, No. 4,02
No. 1,240, British Patent No. 1,486,148 or Belgian Patent No. 786,086 and Japanese Patent Laid-Open No. 50-3.
6143, 50-36110, 50-1160
No. 23, No. 50-99719, No. 50-140113.
No. 51-51933, No. 51-23721, No. 52-84727, or JP-B No. 51-35851, and the present invention is a known reducing agent. Can be appropriately selected and used. The simplest selection method is to actually make a photothermographic material and evaluate the photographic performance of the material to check the superiority or inferiority of the reducing agent used.

Among the above-mentioned reducing agents, when an aliphatic carboxylic acid silver salt is used as the 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, Particularly, an alkyl group (eg, methyl group, ethyl group, propyl group, t-butyl group, cyclohexyl group, etc.) or an 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 substituted 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, 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-di-t-butylphenyl) propane, etc., U.S. Pat. Nos. 3,589,903 and 4,4. No. 021,249 or British Patent No. 1,486,148 and JP-A-5
No. 1-51933, No. 50-36110, No. 50-1
No. 16023, No. 52-84727 or Japanese Patent Publication No. 5
A polyphenol compound described in 1-357727,
Bisnaphthols described in U.S. Pat. No. 3,672,904, such as 2,2'-dihydroxy-1,1 '.
-Binaphtyl, 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, as well as sulfonamide phenols or sulfonamide naphthols such as those described in U.S. Pat. No. 3,801,321, such as 4-benzenesulfonamide. Phenol, 2-benzenesulfonamide phenol, 2,6-dichloro-4-benzenesulfonamide phenol, 4-benzenesulfonamide naphthol and the like can be mentioned.

The amount of the reducing agent used in the photothermographic material of the present invention varies depending on the type of the organic silver salt, the reducing agent and other additives, but generally it is 0. A suitable amount is 05 to 10 mol, preferably 0.1 to 3 mol. Further, within the range of this amount, two or more kinds of the above-mentioned reducing agents may be used in combination.

In the photothermographic material of the present invention, it is desirable to use an additive called a tone adjusting agent, a tone providing agent or an activator toner (hereinafter referred to as a tone adjusting agent) together with the above-mentioned respective components. The toning agent has a function of participating in the redox reaction between the 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. 1
No. 7029, the following are available.

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, 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 + phthal A combination of acids; phthalazine (including an adduct of phthalazine) and maleic anhydride, and phthalic acid, 2,3-naphthalenedicarboxylic acid or o-phenylene acid derivative and its anhydride (for example,
Phthalic acid, 4-methylphthalic acid, 4-nitrophthalic acid and tetrachlorophthalic anhydride) in combination with at least one compound; quinazolinediones, benzoxazine, naltoxazine 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). A preferred color tone agent is phthalazone or phthalazine.

Binders suitable for the photothermographic material of the present invention are transparent or translucent and generally colorless, and include natural polymers, synthetic polymers and copolymers, and other film-forming media such as gelatin, gum arabic and 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,
Examples thereof include polyvinyl formal, polyvinyl butyral, polyesters, polyurethanes, phenoxy resins, polyvinylidene chloride, polyepoxides, polycarbonates, polyvinyl acetates, cellulose esters, polyamides and the like, which may be hydrophilic or non-hydrophilic. 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.

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 photosensitive material in order to prevent the image from being scratched after heat development. Is preferably contained in an amount of 0.5 to 30% 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 a support sandwiched between them, it is preferable to include a matting agent in at least one layer on the non-photosensitive layer side, so that the slipperiness of a photosensitive material and the adhesion of fingerprints can be prevented. For prevention, it is preferable to dispose a matting agent on the surface of the light-sensitive material, and the matting agent is used in a mass ratio of 0.5 to 4 with respect to all binders in the layer opposite to the light-sensitive layer side.
It is preferable to contain 0%.

The material of the matting agent may be either organic or inorganic. For example, as an inorganic matting agent, silica described in Swiss Patent No. 330,158, glass powder described in French Patent No. 1,296,995, British Patent No. 1,173,181, etc. Examples thereof include the alkaline earth metals or carbonates such as cadmium and zinc. As an organic matting agent, US Pat. No. 2,322,037
Nos., Etc., Belgian Patent No. 625,451, Starch Derivatives described in British Patent No. 981,198, etc., Polyvinyl alcohol described in Japanese Patent Publication No. 44-3643, etc., Swiss Patent No. 330,158 Polystyrene or polymethacrylate described in US Pat.
Examples thereof include polyacrylonitrile described in 079,257 and the like, and polycarbonate described in US Pat. No. 3,022,169 and the like.

The shape of the matting agent may be either a fixed shape or an amorphous shape, but a fixed shape is preferred, 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. The particle size of the matting agent means the spherically converted diameter. The matting agent preferably has an average particle size of 0.5 to 10 μm, more preferably 1.0 to 8.0 μm. Further, 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 may be contained in any constituent layer, but in order to achieve the object of the present invention, preferably a composition other than the photosensitive layer. It is a layer, more preferably the outermost layer as viewed from the support.

The matting agent may be added by dispersing it in the coating solution in advance, or by spraying the matting agent after the coating solution is applied and before the drying is completed. Good. When adding a plurality of types of matting agents, both methods may be used in combination.

The photothermographic material of the present invention includes, for example, JP-A Nos. 63-159841 and 60-140335.
63-231437, 63-259651, 63-304242, 63-15245, U.S. Pat. Nos. 4,639,414, 4,740,455,
The sensitizing dyes described in Nos. 4,741,966, 4,751,175, and 4,835,096 can be used.

In the present invention, the wavelength is 720 to 1000.
It is more preferable to perform spectral sensitization to 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-2-48 are available.
No. 635, U.S. Pat. No. 2,161,331, West German Patent No. 936,071, Japanese Patent Application No. 3-189532, etc., the simple merocyanines and the helium neon laser light source are disclosed in JP-A-50- No. 62425, 54-
18726 and 59-102229, trinuclear cyanine dyes, merocyanines described in Japanese Patent Application No. 6-103272, LED light sources and infrared semiconductor laser light sources, Japanese Patent Publication No. 48-17272. , Ibid 51-9
609, 55-39818, JP-A-62-284.
No. 343, JP-A No. 2-105135, and thiacarbocyanines and infrared semiconductor laser light sources described in JP-A-59-191032 and JP-A-60-808.
No. 41, tricarbocyanines, JP-A-59
-192242 and dicarbocyanines containing a 4-quinoline nucleus described in the general formulas (IIIa) and (IIIb) of JP-A-3-67242 are advantageously selected.

Furthermore, the wavelength of the infrared laser light source is 750n.
m or more, and more preferably 800 nm or more, in order to deal with a laser having such a wavelength range, JP-A-4-
No. 182639, No. 5-341432, Japanese Patent Fair 6-5
2387, 3-10931, US Pat. No. 5,44
Sensitizing dyes described in JP-A No. 1,866, JP-A No. 7-13295 and the like 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.

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 or on the opposite side of the photosensitive layer in order to control the amount or wavelength distribution of light transmitted through the photosensitive layer, or the photosensitive layer may contain a dye or a pigment. As the dye, the compounds described in JP-A-8-201959 are preferable. The photosensitive layer may be composed of a plurality of layers, and a high-sensitivity layer and a low-sensitivity layer may be provided for adjusting gradation and these may be combined.
Various additives may be added to any of the light-sensitive layer, the non-light-sensitive layer and 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.

All the 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 multilayer 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.

Further, before drying the already coated layer by using a plurality of coaters, the next layer is coated to dry the plurality of layers at the same time, or slide coating, curtain coating or an extrusion type die coater having a plurality of slits. A simultaneous multi-layer coating method in which a plurality of coating liquids are laminated and coated by using is also used. Of these, the latter is more preferable because it can prevent the occurrence of coating failure due to foreign matter brought in from the outside.

Further, when the simultaneous multi-layer coating method is used,
To prevent mixing between layers, the viscosity of the uppermost layer coating liquid should be 0.1 Pa · s or more and the viscosity of other layer coating liquid should be 0.03 Pa · s or more. Is preferred. 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. The same amount of organic solvent is contained in the coating liquid for each layer (the content of the organic solvent commonly contained in each coating liquid in each liquid is higher than that in other organic solvents).
Is preferred.

It is preferable that the coating is dried as soon as possible after the multi-layer coating, and it is preferable to reach the drying step within 10 seconds in order to avoid inter-layer mixing due to flow, diffusion, density difference and the like. 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.

For exposure of the photothermographic material of the present invention, an argon ion laser (488 nm), a He-Ne laser (633 nm), a red semiconductor laser (670 n) are used.
m), infrared semiconductor laser (780 nm, 820 nm)
Etc. are preferably used, but from the viewpoint that the laser power is high and the photosensitive material can be made transparent,
An infrared semiconductor laser is more preferably used.

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

Here, the phrase "substantially vertical" does not mean that the angle is the most vertical during laser scanning, preferably 55 degrees or more and 88 degrees or less, and more preferably 6 degrees or less.
0 degrees or more and 86 degrees or less, more preferably 65 degrees or more, 8
It is 4 degrees or less, most preferably 70 degrees or more and 82 degrees or less.

The beam spot diameter 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-shape. 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, a method of applying 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.
It is preferable that the thickness is not less than nm. The upper limit of the exposure wavelength distribution is not particularly limited, but is usually about 60 nm.

The photothermographic material of the present invention is stable at room temperature, but 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. On the other hand, if the heating temperature is 200 ° C or higher, the binder melts, and transfer to a roller is performed, not only for the image itself but also for transportability and a developing machine. Adversely affect. 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.

[0081]

The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto.

Example 1 (Preparation of Photosensitive Silver Halide Emulsion 1) (A1) Phenylcarbamoyl gelatin 88.3 g Compound (A) (10% methanol solution) 10 ml Potassium bromide 0.32 g Water to make 5429 ml (B1) ) 0.67M silver nitrate aqueous solution 2635ml (C1) potassium bromide 51.55g potassium iodide 1.47g finished to 660ml with water (D1) potassium bromide 154.9g potassium iodide 4.41g (E1) 0.4M bromide Aqueous potassium solution Silver potential control amount (F1) 56% Acetic acid aqueous solution 16.0 ml (G1) Anhydrous sodium carbonate 1.72 g Finish with water to 151 ml Compound (A): HO (CH ₂ CH ₂ O) _n- [CH (CH ₃₎ CH ₂ O] _{17 - (CH 2 CH 2 O} ) m H m + n = 5~7 Sho 58-58288 , Using a mixing and stirring machine shown in Nos. 58-58289, solution to a solution (A1) (B
1/4 amount of 1) and the total amount of the solution (C1) are 39 ° C., pAg
While controlling at 8.09, the mixture was added for 4 minutes and 45 seconds by the simultaneous mixing method to perform nucleation.

After 7 minutes, the rest of the solution (B1) and the total amount of the solution (D1) were added by the simultaneous mixing method over 14 minutes and 15 seconds while controlling the temperature at 45 ° C. and pAg 8.09. During the mixing, the pH of the reaction solution was 5.6.

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. The supernatant was removed, leaving 2000 ml of the sedimented portion, 10 L of water was added, and after 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 Photosensitive Silver Halide Emulsion 2) In the process of preparing photosensitive silver halide emulsion 1, the solution (D
1) 0.93 m of iridium chloride aqueous solution (1% solution)
A light-sensitive silver halide emulsion 2 was prepared in exactly the same manner except that the amount of 1 was added.

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.

The amount of iridium contained in the silver halide grains was 8.2 × 10 ^-6 mol per mol of silver.

(Preparation of powdered organic silver salt 1) In 4720 ml of pure water, 130.8 g of behenic acid and 67.7 of arachidic acid were added.
g, stearic acid 43.6 g, and palmitic acid 2.3 g were dissolved 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 an organic acid sodium salt solution. While maintaining the temperature of this organic acid sodium salt solution at 55 ° C., 45.3 g of the above-mentioned photosensitive silver halide emulsion 2 and 450 ml of pure water were added and stirred for 5 minutes.

Next, 702.6 ml of a 1 M silver nitrate solution was added over 2 minutes and stirred for 10 minutes to obtain an organic silver salt dispersion. After that, the obtained organic silver salt dispersion was transferred to a water washing container, deionized water was added, and the mixture was stirred and allowed to stand to separate the organic silver salt dispersion by flotation, and the lower water-soluble salts were removed.
After that, washing with deionized water and drainage were repeated until the conductivity of the wastewater reached 2 μS / cm, centrifugal dehydration was performed, and then drying was performed with a warm air circulation dryer at 40 ° C. until the mass loss disappeared, A powdered organic silver salt 1 was obtained.

(Preparation of powdered organic silver salt 2) Powdered organic silver salt 1
A powdered organic silver salt 2 was obtained in exactly the same manner except that the photosensitive silver halide emulsion 1 was used in place of the photosensitive silver halide emulsion 2 in the preparation step of.

(Preparation of powdered organic silver salt 3) Powdered organic silver salt 2
In the preparation step of 1., before adding the obtained organic silver salt dispersion to a washing container, an aqueous solution of iridium chloride is added in an amount of 1.0 × 10 ⁻⁵ mol per mol of silver halide, and the mixture is stirred for 10 minutes. Powdered organic silver salt 3
Got

(Preparation of powdered organic silver salt 4) Powdered organic silver salt 1
In the preparation step of 1., a powdered organic silver salt 4 was obtained in exactly the same manner except that the position of addition of the photosensitive silver halide emulsion 2 was moved to the water washing container and stirring was continued for 10 minutes.

(Preparation of powdered organic silver salt 5) Powdered organic silver salt 1
A powdered organic silver salt 5 was obtained in exactly the same manner except that the photosensitive silver halide emulsion 2 was not added in the preparation step of.

(Preparation of Pre-dispersion) Polyvinyl butyral powder (manufactured by Monsanto, Butvar B-7)
9) Dissolve 14.57 g in 1457 g of methyl ethyl ketone, and dissolver DIS manufactured by VMA-GETZMANN
While stirring with a PERMAT CA-40M type, 500 g of each powdered organic silver salt obtained was gradually added and sufficiently mixed to prepare Preliminary Dispersions 1 to 5.

<Preparation of Photosensitive Emulsion Dispersion> Preliminary Dispersion 1
~ 5, using a pump, the residence time in the mill is 10
It is supplied to a media type disperser DISPERMAT SL-C12EX (VMA-GETZMANN) in which 80% of the inner volume is filled with zirconia beads having a diameter of 0.5 mm (Toray's Treceram) so that the peripheral speed of the mill is 13 m. / S was used to prepare photosensitive emulsion dispersions 1 to 5.

(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 1, 1.488 g of 2-chloro-benzoic acid, 2.779 g of stabilizer 2 and 365 mg of 5-methyl-2. -Mercaptobenzimidazole 31.3m
It was dissolved in 1 MEK in the dark to prepare an infrared sensitizing dye solution.

(Preparation of additive liquid a) 27.98 g of reducing agent A-3, 1.54 g of 4-methylphthalic acid, 0.48 g
Infrared Dye 1 of 1 was dissolved in 110 g of MEK to obtain an additive liquid 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.

[0101]

[Chemical 1]

<Preparation of Photosensitive Layer Coating Liquids 1 to 4> 50 g of each of the photosensitive emulsion dispersions 1 to 4 and MEK 15.11.
While keeping the mixture at a temperature of 21 ° C with stirring, antifoggant 1 (1
390 μl of 0% methanol solution) was added and stirred for 1 hour. Furthermore, calcium bromide (10% methanol solution) 4
94 μl was added and stirred for 20 minutes. Subsequently, after adding 167 mg of the stabilizer solution and stirring for 10 minutes, 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 30 minutes.
While keeping the temperature at 13 ℃, polyvinyl butyral (Mon
Santo Company Butvar B-79) 13.31 g
Was added and stirred for 30 minutes, then 1.084 g of tetrachlorophthalic acid (9.4% by mass MEK solution) was added to
Stir for 5 minutes. While continuing stirring, 12.43 g
Addition liquid a, 1.6 ml of Desmodur N3300
/ Mobey's aliphatic isocyanate (10% MEK
Solution) 4.37 g of the additive liquid b was sequentially added and stirred to obtain photosensitive layer coating liquids 1 to 4.

[0103]

[Chemical 2]

<< Preparation of Photosensitive Layer Coating Liquid 5 >> Photosensitive Layer Coating Liquid 2
In the step of preparing the same, the photosensitive layer was prepared in the same manner except that the antifoggant 1 was added and, after 30 minutes, a methanol solution of iridium chloride was added so as to be 1.0 × 10 ⁻⁵ mol per mol of silver halide. A coating liquid 5 was obtained.

<< Preparation of Photosensitive Layer Coating Liquid 6 >> Photosensitive Layer Coating Liquid 5
A photosensitive layer coating liquid 6 was obtained in exactly the same manner except that the photosensitive emulsion dispersion liquid 5 was used in place of the photosensitive emulsion dispersion liquid 2 in the preparation step.

(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 dispersed by a dissolver type homogenizer at 8000 rpm for 30 minutes to prepare a matting agent dispersion liquid.

<< Preparation of Surface Protective Layer Coating Liquid >> MEK865
g with stirring, 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 Co., Surflon KH40)
1.0 g was added and dissolved. Next, 30 g of the above-mentioned matting agent dispersion liquid was added and stirred to prepare a surface protective layer coating liquid.

[0108]

[Chemical 3]

[Preparation of Photosensitive Materials 1 to 6] Photosensitive Layer Coating Solution 1
By adjusting the amount of the solvent and the viscosity of the coating solution for the surface protective layer, 0.228 Pa · s and 0.184 Pa · s, respectively.
s and pass through a filter with a quasi-absolute filtration accuracy of 20 μm,
After filtration, the mixture was discharged from a slit of an extrusion type die coater, laminated, and simultaneously multilayer-coated on a support.
8 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., 23 ° C., 50% RH, tension of 19
A light-sensitive material 1 was produced by winding it in a roll at 6 N / m (20 kg / m). The coated silver amount of the photosensitive layer of the obtained photosensitive material was 1.9 g / m ² , and the dry film thickness of the surface protective layer was 2.5 μm.

Photosensitive layers 2 to 6 were coated in the same manner to prepare photosensitive materials 2 to 6. [Exposure and development processing] From the emulsion side of the light-sensitive material produced as described above, a wavelength of 800 to 820 nm is superimposed by high frequency superposition.
An exposure machine using a vertical multimode semiconductor laser as a light emitting source was used to perform exposure by laser scanning. At this time, the angle between the exposed surface of the photosensitive material and the exposure laser beam is set to 7
The image was formed at 5 degrees. (Note that an image with less unevenness and unexpectedly good sharpness was obtained compared to the case where the angle was 90 degrees.) After that, the photosensitive material was processed using an automatic developing machine 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 result of the measurement is sensitivity (1.
0 The reciprocal of the ratio of the exposure dose giving a high density) and the sensitometry of fog were evaluated, and the sensitivity of the photosensitive material 1 was set to 100.
The relative values are shown in Table 1.

[Evaluation of image storability] Two samples treated in the same manner as in the sensitometry evaluation were used, 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 image storability was evaluated as follows, and the results are shown in Table 1.

Increased fog = fogged when exposed to natural light-fogged when stored with shading

[0113]

[Table 1]

From Table 1, it can be seen that the sample of the present invention has better sensitivity and fog sensitometry than the comparative sample, and further, the increase of fog during image storage is small.

Example 2 (Preparation of Photosensitive Silver Halide Emulsion 3) In the step of preparing photosensitive silver halide emulsion 1, 0.93 ml of an aqueous solution of iridium chloride (1% solution) and an aqueous solution of potassium ferrocyanide were added to solution (D1). Photosensitive silver halide emulsion 3 in exactly the same manner except that 0.81 ml of (1% solution) was added.
Was prepared.

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. The amount of iridium contained in the silver halide grains is 8.
2 × 10 ^-6 mol, the amount of iron is 8.3 × 10 per mol of silver
^-6 mol.

(Preparation of Photosensitive Silver Halide Emulsion 4) In the process of preparing the photosensitive silver halide emulsion 1, the solution (D
A photosensitive silver halide emulsion 4 was prepared in the same manner except that 0.81 ml of an aqueous potassium ferrocyanide solution (1% solution) was added to 1).

This emulsion has an average grain size of 0.048μ.
m, variation coefficient of particle size 12%, [100] plane ratio 9
It was 2% of cubic silver iodobromide grains. The amount of iron contained in the silver halide grains is 8.3 × 1 per mol of silver.
It was 0 ^-6 mol.

(Preparation of powdered organic silver salt 7) Powdered organic silver salt 1
A powdered organic silver salt 7 was obtained in exactly the same manner except that the photosensitive silver halide emulsion 3 was used in place of the photosensitive silver halide emulsion 2 in the preparation step of.

(Preparation of powdered organic silver salt 8) Powdered organic silver salt 1
A powdered organic silver salt 8 was obtained in exactly the same manner except that the photosensitive silver halide emulsion 4 was used in place of the photosensitive silver halide emulsion 2.

(Preparation of powdered organic silver salt 9) Powdered organic silver salt 2
In the preparation step of 1, the iridium chloride and potassium ferrocyanide are each added in an amount of 1.0 × 10 6 per mol of silver halide before the obtained organic silver salt dispersion is transferred to a water washing container.
^A powdered organic silver salt 9 was obtained in exactly the same manner except that the amount of ^-5 mol was added and the ^mixture was stirred for 10 minutes.

(Preparation of powdered organic silver salt 10) In the step of preparing powdered organic silver salt 2, potassium ferrocyanide was added to 1.0 mol per mol of silver halide before transferring the obtained organic silver salt dispersion to a water washing container. Powdered organic silver salt 10 was obtained in exactly the same manner except that an amount of × 10 ^-5 mol was added and stirring was continued for 10 minutes.

(Preparation of powdered organic silver salt 11) In the step of preparing powdered organic silver salt 7, except that the addition position of photosensitive silver halide emulsion 3 was moved to a water washing container, and stirring was further performed for 10 minutes. In the same manner, powdered organic silver salt 11 was obtained.

(Preparation of powdered organic silver salt 12) In the step of preparing powdered organic silver salt 8, except that the addition position of photosensitive silver halide emulsion 4 was moved to a water washing container, and stirring was continued for 10 minutes. In the same manner, powdered organic silver salt 12 was obtained.

<Preparation of Photosensitive Emulsion Dispersion Liquid> In the same manner as in the photosensitive emulsion dispersion liquids 1 to 5, a preliminary dispersion liquid was prepared from powdered organic silver salts 7 to 12, and then the photosensitive emulsion dispersion liquids 7 to 12 were prepared.
I got 12.

<< Preparation of Photosensitive Layer Coating Liquids 7 to 12 >> Photosensitive emulsion dispersions 7 to 12 were prepared in the same manner as the preparation of the photosensitive layer coating liquids 1 to 4.
Photosensitive layer coating solutions 7 to 12 were obtained using 12 respectively.

<< Preparation of Photosensitive Layer Coating Liquid 13 >> In the step of preparing the photosensitive layer coating liquid 2, 30 minutes after the addition of the antifoggant 1, iridium chloride and potassium ferrocyanide were each added at 1.0 × 10 3 per mol of silver halide. ^A photosensitive layer coating liquid 13 was obtained in exactly the same manner except that the addition amount was ^-5 mol.

<< Preparation of Photosensitive Layer Coating Liquid 14 >> In the step of preparing Photosensitive Layer Coating Liquid 2, 30 minutes after the addition of antifoggant 1, potassium ferrocyanide was adjusted to 1.0 × 10 ⁻⁵ mol per mol of silver halide. A photosensitive layer coating liquid 14 was obtained in exactly the same manner except that the addition was performed as described above.

<< Preparation of Photosensitive Layer Coating Liquid 15 >> In the process of preparing the photosensitive layer coating liquid 13, the photosensitive layer coating liquid was coated in exactly the same manner except that the photosensitive emulsion dispersion liquid 5 was used in place of the photosensitive emulsion dispersion liquid 2. Liquid 15 was obtained.

<< Preparation of Photosensitive Layer Coating Liquid 16 >> The photosensitive layer coating liquid 14 was prepared in exactly the same manner except that the photosensitive emulsion dispersion liquid 5 was used in place of the photosensitive emulsion dispersion liquid 2. Liquid 16 was obtained.

[Preparation and Evaluation of Photosensitive Materials 7 to 16] Photosensitive materials 7 to 16 were prepared in the same manner as in Example 1 using the photosensitive layer coating liquids 7 to 16. Using these, the same evaluation as in Example 1 was performed. The results are shown in Table 2.

[0132]

[Table 2]

From Table 2, it can be seen that the sample of the present invention has better sensitivity and fog sensitometry than the comparative sample, and the increase of fog during image storage is small.

Example 3 A photosensitive material was prepared in the same manner as in Example 1 except that rhodium chloride and ruthenium chloride were used instead of iridium chloride, and the same evaluations were carried out. The effect of was obtained.

[0135]

The production method of the present invention provides high sensitivity,
It was possible to obtain a photothermographic material having low fog and good image storability.

Claims (9)

[Claims] 1. At least a non-photosensitive organic silver salt, a photosensitive silver halide, a reducing agent capable of reducing silver ions of the organic silver salt to silver when activated by heat, a binder, and crosslinking of the binder. In the method for producing a photothermographic material containing an agent, at least one transition metal selected from the elements of Groups 6 to 11 of the periodic table of elements is added to the step after the organic silver salt is formed. A method for producing a photothermographic material, which is characterized. 2. A non-photosensitive organic silver salt, a photosensitive silver halide, a reducing agent capable of reducing silver ions of the organic silver salt to silver when activated by heat, a binder, and crosslinking of the binder. In the method for producing a photothermographic material containing an agent, a photosensitive material obtained by doping at least one transition metal selected from the elements of Groups 6 to 11 of the periodic table in the step after the organic silver salt is formed. A method for producing a photothermographic material, which comprises adding silver halide. 3. A non-photosensitive organic silver salt, a photosensitive silver halide, a reducing agent capable of reducing silver ions of the organic silver salt to silver when activated by heat, a binder, and crosslinking of the binder. In the method for producing a photothermographic material containing an agent, the organic silver salt is formed in the presence of a photosensitive silver halide which is not doped with a transition metal selected from elements of Groups 6 to 11 of the periodic table of elements. And reacting the organic silver salt with a halogen supplier in an organic solvent in the presence of at least one transition metal to further form a photosensitive silver halide. Method. 4. The photothermographic material according to claim 1, wherein the average equivalent silver particle diameter of the photosensitive silver halide is 0.03 μm or more and 0.20 μm or less. Manufacturing method. 5. The transition metal is iron, cobalt, ruthenium,
The method for producing a photothermographic material according to any one of claims 1 to 4, which is a metal selected from rhodium, rhenium, osmium, and iridium. 6. A photothermographic material obtained by the manufacturing method according to claim 1. 7. The photothermographic material according to claim 6, which is spectrally sensitized to 720 to 1000 nm. 8. An image recording method, which comprises exposing the photothermographic material according to claim 6 or 7 by a laser exposure machine. 9. An image forming method comprising developing the photothermographic material according to claim 6 or 7 by heating at a temperature of 80 ° C. or higher and 200 ° C. or lower.