JP2000267221A - Heat developable image forming material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a heat developable image forming material which gives a sufficient image density even after long-term preservation and suppresses the sublimation of components liable to cause problem in processing by holding a reducible silver salt, a reducing agent, a binder and at least one specified compound on at least one face of a substrate. SOLUTION: A reducible silver salt, a reducing agent, a binder and a polymer having repeating units derived from a compound of formula I or a compound of formula II as a monomer are held on at least one face of a substrate. In the formula I, M is H or a counter ion, Y is a substituent, L is a divalent combining group, B is a ballast group, (m) is an integer of 0-4 and (n) is an integer of 1-4. In the formula II, M is H or a counter ion, Y is a substituent, Q is a group containing at least one carbon-carbon double bond and (m) is an integer of 0-4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a heat-developable image forming material using an organic silver salt image forming medium. More specifically, the present invention relates to a heat-developable image-forming material having a high image density and an extremely small increase in fog upon storage.

[0002]

2. Description of the Related Art There are many known photosensitive materials having a photosensitive layer on a support and forming an image by exposing the image. Among them, a technique for forming an image by thermal development is a system that can simplify environmental preservation and image forming means. In recent years, from the viewpoints of environmental conservation and space saving, it is strongly desired to reduce the amount of processing waste liquid. Accordingly, the present invention relates to a photothermographic material for medical diagnosis and photographic technology, which can be efficiently exposed by a laser imagesetter or a laser imager and can form a black image having high resolution and sharpness. Technology is needed. These photosensitive heat-developable materials eliminate the use of solution-based processing chemicals, and can provide customers with a simpler heat-development system that does not damage the environment.

A method of forming an image by thermal development is described in, for example, US Pat. Nos. 3,152,904 and 3,457,0
No. 75; Morgan and B.A. Sherry
(Shely) "Heat Treated Silver System (Th
ermally Processed Silver Systems ”(Imaging Pros and Materials)
cesses and Materials) Neblette 8th edition, Sturge (St
urge), V.I. Walworth, A .; Shepp, page 2, 1969). Such photosensitive materials are prepared by dispersing a reducible non-photosensitive silver source (eg, an organic silver salt), a catalytically active amount of a photocatalyst (eg, silver halide), and a silver reducing agent, usually in an organic binder matrix. It is contained in. The photosensitive material is stable at normal temperature, but when heated to a high temperature (for example, 80 ° C. or higher) after exposure, silver is reduced through a redox reaction between a reducible silver source (which functions as an oxidizing agent) and a reducing agent. Generate This oxidation-reduction reaction is promoted by the catalytic action of the latent image generated by the exposure. The silver formed by the reaction of the reducible silver salt in the exposed areas provides a black image, which contrasts with the unexposed areas, resulting in the formation of an image.

In the above-mentioned heat-developable photographic material, additives generally known as "toning agents" are used for the purpose of obtaining an image having a high maximum density, improving the color tone of developed silver, and improving developability. Used as needed. In the photothermographic material utilizing an organic silver salt, a wide range of color toning agents are disclosed in JP-A-46-6077, JP-A-47-10282, JP-A-49-5019, and JP-A-49-502.
No. 0, No. 49-91215, No. 49-91215, No. 50-2524, No.
No. 50-32927, No. 50-67132, No. 50-67641, No. 50-11421
No. 7, No. 51-3223, No. 51-27923, No. 52-14788, No.
52-99813, 53-1020, 53-76020, 54-15652
No. 4, 54-156525, 61-183642, JP-A-4-5684
No. 8, JP-B-49-10727, JP-B-54-20333, U.S. Pat.
No. 080,254, No. 3,446,648, No. 3,782,941, No. 4,123,282, No. 4,510,236, British Patent No. 138079
No. 5, Belgian Patent No. 841910 and the like.

Examples of known color toning agents include phthalazinones (eg, phthalazinone, 4- (1-naphthyl) phthalazinone, 6-chlorophthalazinone, 5,7-dimethoxyphthalazinone and 2,3-dihydro-1. , 4-phthalazinedion),
Phthalazinone and phthalic acid derivatives (eg, phthalic acid, 4-
Combinations with methylphthalic acid, 4-nitrophthalic acid and tetrachlorophthalic anhydride, and phthalazines (eg, phthalazine, 5-methylphthalazine, 6-methylphthalazine, 5,7-dimethylphthalazine, 6-ethylphthalate) Razine, 6-isopropylphthalazine, 6-i-butylphthalazine, 6-t-butylphthalazine, 4- (1-naphthyl) phthalazine, 6-acetylphthalazine, 6-chlorophthalazine, 5,7-dimethoxy Phthalazine and 2,3-dihydrophthalazine, etc.), a combination of phthalazine and a phthalic acid derivative, a cyclic imide (for example, phthalimide, N-hydroxyphthalimide, succinimide, pyrazoline-5-
On, and quinazolinone, 3-phenyl-2-pyrazolin-5-one, 1-phenylurazole, quinazoline and
2,4-thiazolidinedione, naphthalimide, N-hydroxy-1,8-naphthalimide), N- (aminomethyl) aryldicarboximide (for example, (N, N-dimethylaminomethyl) phthalimide and N, N- (Dimethylaminomethyl) -naphthalene-2,3-dicarboximide), quinazolinedione, benzoxazine or naphthoxazine derivative,
Cobalt complexes (eg, cobalt hexamine trifluoroacetate), mercaptans (eg, 3-mercapto-1,2,4-triazole, 2,4-dimercaptopyrimidine, 3-mercapto-4,5-diphenyl-1,2 , 4-Triazole and 2,5-dimercapto-1,3,4-thiadiazole), blocked pyrazoles, isothiuronium derivatives and certain photobleaching agents (e.g., N, N'-hexamethylenebis (1-
Carbamoyl-3,5-dimethylpyrazole), 1,8- (3,6-diazaoctane) bis (isothiuronium trifluoroacetate) and 2-tribromomethylsulfonyl) benzothiazole, 3-ethyl-5 [(3- Ethyl-2-benzothiazolinylidene) -1-methylethylidene] -2-thio-2,4-oxazolidinedione), not only as a color tone regulator but also as a halide ion for silver halide formation in situ. Rhodium complexes that also function as sources (such as ammonium hexachlororhodate (III), rhodium bromide, rhodium nitrate and potassium hexachlororhodate (III)),
Inorganic peroxides and persulfates (eg, ammonium disulfide) and hydrogen peroxide, benzoxazine-2,4
-Diones such as 1,3-benzoxazine-2,4-dione, 8-methyl-1,3-benzoxazine-2,4-dione and 6-nitro-1,3-benzoxazine-2,4 -Zeon),
Pyrimidine and asymmetric-triazines (eg, 2,4-dihydroxypyrimidine, 2-hydroxy-4-aminopyrimidine, etc.), azauracil, and tetraazapentalene derivatives (eg, 3,6-dimercapto-1,4-diphenyl- 1
H, 4H-2,3a, 5,6a-tetraazapentalene, and 1,4-di
(o-chlorophenyl) -3,6-dimercapto-1H, 4H-2,3a, 5,6
a-tetraazapentalene) and the like.

[0006] These color toning agents are required not only to give a good silver tone, but also to have various performances such as sufficient image density, appropriate development temperature characteristics, development progress, and storage stability. As a preferred example of the color tone agent, a combination of phthalazinone and phthalic acid has been conventionally selected. However, when a photosensitive layer is formed using a combination of phthalazinone and phthalic acid, the following problems may occur due to the high sublimability of these compounds, and improvement thereof has been a problem. . That is: 1) When the heat-developable photographic material is stored for a long period of time, a sufficient image density may not be obtained when heat-development is performed. 2) At the time of heat development, the toning agent may sublimate from the heat-developable photographic material and adhere to the inside of the heat-development machine, which may cause deterioration in image quality of the processed photographic material.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to solve these problems of the prior art. That is, the present invention is to solve the problem of providing a heat-developable image-forming material which gives a sufficient image density even when stored for a long period of time and which has a very low degree of sublimation of a material which may be a problem during processing. Assigned.

[0008]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, have found that the compound represented by the general formula (I) or the compound represented by the general formula (I) described in the present specification.
It has been found that by incorporating a polymer having a repeating unit derived from the compound represented by I) as a monomer, an excellent heat-developable image-forming material having desired effects can be provided, and the present invention is provided. Reached.

That is, according to one embodiment of the present invention, (a) a reducible silver salt, (b) a reducing agent, (c) a binder, and (d) There is provided a heat-developable image-forming material comprising at least one compound represented by the formula (I).

Embedded image [Wherein, M represents a hydrogen atom or a counter ion, Y represents a substituent, L represents a divalent linking group, and B represents a ballast group. m represents an integer of 0 or more and 4 or less, and n represents an integer of 1 or more and 4 or less. ]

According to another aspect of the present invention, (a) a reducible silver salt is provided on at least one same surface of a support,
(B) containing at least one kind of a polymer having a repeating unit derived from a compound represented by the following general formula (II) as a monomer: A developed imaging material is provided.

Embedded image [Wherein, M represents a hydrogen atom or a counter ion, Y represents a substituent, Q represents a group containing at least one carbon-carbon double bond, and m represents an integer of 0 or more and 4 or less. ]

Preferably, the heat-developable image-forming material of the present invention further comprises (e) a photosensitive silver halide on the same surface. Preferably, the heat-developable image-forming material of the present invention further comprises (f) a super-high contrast agent on the same surface. Preferably, the ultrahigh contrast agent has the general formula (III), the general formula (I)
V) and one or more compounds selected from the group of compounds represented by formula (V).

Embedded image [In the general formula (III), R ¹ , R ² and R ³ each independently represent a hydrogen atom or a substituent, and Z represents an electron-withdrawing group or a silyl group. In the general formula (III), R ¹ and Z, R ² and R ³ , R ¹ and R ² , or R ³ and Z may be bonded to each other to form a cyclic structure. General formula (IV)
In the above, R ⁴ represents a substituent. In the general formula (V), X and Y each independently represent a hydrogen atom or a substituent;
A and B each independently represent an alkoxy group, an alkylthio group, an alkylamino group, an aryloxy group, an arylthio group, an anilino group, a heterocyclic oxy group, a heterocyclic thio group, or a heterocyclic amino group. In the formula (V), X
And Y or A and B may combine with each other to form a cyclic structure. ]

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION In the following, embodiments and methods of the heat-developable image forming material of the present invention will be described in detail. The heat-developable image-forming material of the present invention comprises (a) a reducible silver salt on at least one same surface of a support,
(B) a reducing agent, (c) a binder, and (d) a compound represented by the following general formula (I) or a compound represented by the following general formula (I)
Characterized by containing a polymer having a repeating unit derived from the compound represented by I) as a monomer, and optionally further comprising (e) a photosensitive silver halide and / or (f) It is characterized by having.

First, general formulas (I) and (II)
The compound represented by is described. In the general formulas (I) and (II), Y represents a substituent, and these substituents may be bonded to each other to form a ring. As the substituent, for example, an alkyl group (preferably having 1 to 2 carbon atoms)
0, more preferably 1 to 12 carbon atoms, particularly preferably 1 to 8 carbon atoms, such as methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl,
tert-butyl, n-octyl, n-decyl, n-hexadecyl, cyclopropyl, cyclopentyl, cyclohexyl and the like. ), An alkenyl group (preferably having 2 to 20 carbon atoms, more preferably having 2 to 12 carbon atoms,
Particularly preferably, it has 2 to 8 carbon atoms, and examples thereof include vinyl, allyl, 2-butenyl, and 3-pentenyl. ), Alkynyl group (preferably 2-20 carbon atoms, more preferably 2-12, particularly preferably 2-8,
For example, propargyl, 3-pentynyl and the like can be mentioned. ), An aryl group (preferably having 6 to 30 carbon atoms, more preferably having 6 to 20 carbon atoms, and particularly preferably having 6 to 30 carbon atoms).
12, for example, phenyl, p-methylphenyl, naphthyl and the like. ), An amino group (preferably having 0 to 20 carbon atoms, more preferably 0 to 10 carbon atoms, particularly preferably 0 to 6 carbon atoms, and examples thereof include amino, methylamino, dimethylamino, diethylamino, and dibenzylamino. ), An alkoxy group (preferably having 1 to 20 carbon atoms, more preferably having 1 to 12 carbon atoms, particularly preferably having 1 to 8 carbon atoms, and examples thereof include methoxy, ethoxy, and butoxy), and aryloxy. A group (preferably having 6 to 20 carbon atoms, more preferably having 6 to 16 carbon atoms, particularly preferably having 6 to 12 carbon atoms, such as phenyloxy and 2-naphthyloxy), and an acyl group (preferably 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 1 carbon atoms
2, for example, acetyl, benzoyl, formyl, pivaloyl and the like. ), An alkoxycarbonyl group (preferably having 2 to 20 carbon atoms, more preferably having 2 carbon atoms)
-16, particularly preferably 2-12 carbon atoms, for example, methoxycarbonyl, ethoxycarbonyl and the like. ), An aryloxycarbonyl group (preferably having 7 to 20 carbon atoms, more preferably having 7 to 16 carbon atoms, particularly preferably having 7 to 10 carbon atoms, such as phenyloxycarbonyl, etc.), and an acyloxy group (preferably). Has 2 to 20 carbon atoms, more preferably 2 to 1 carbon atoms.
6, particularly preferably having 2 to 10 carbon atoms, such as acetoxy and benzoyloxy. ), An acylamino group (preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, particularly preferably having 2 to 10 carbon atoms, for example, acetylamino, benzoylamino and the like), and an alkoxycarbonylamino group (Preferably 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms,
Particularly preferably, it has 2 to 12 carbon atoms, such as methoxycarbonylamino. ), An aryloxycarbonylamino group (preferably having 7 to 20 carbon atoms, more preferably having 7 to 16 carbon atoms, and particularly preferably having 7 carbon atoms.
To 12, for example, phenyloxycarbonylamino and the like. ), A sulfonylamino group (preferably having 1 to 20 carbon atoms, more preferably having 1 to 16 carbon atoms, particularly preferably having 1 to 12 carbon atoms, for example, methanesulfonylamino, benzenesulfonylamino, etc.), and sulfamoyl. Group (preferably having 0 to 2 carbon atoms)
It has 0, more preferably 0 to 16 carbon atoms, and particularly preferably 0 to 12 carbon atoms, and examples thereof include sulfamoyl, methylsulfamoyl, dimethylsulfamoyl, and phenylsulfamoyl. ), A carbamoyl group (preferably having 1 to 20 carbon atoms, more preferably having 1 to 1 carbon atoms)
6, particularly preferably 1 to 12 carbon atoms, for example, carbamoyl, methylcarbamoyl, diethylcarbamoyl, phenylcarbamoyl and the like. ), An alkylthio group (preferably having 1 to 20 carbon atoms, more preferably having 1 to 16 carbon atoms, particularly preferably having 1 to 12 carbon atoms, such as methylthio and ethylthio, etc.), and an arylthio group (preferably having carbon thiol). Equations 6 to 20,
More preferably, it has 6 to 16 carbon atoms, particularly preferably 6 to 12 carbon atoms, such as phenylthio. ), A sulfonyl group (preferably having 1 to 20 carbon atoms, more preferably having 1 to 16 carbon atoms, and particularly preferably having 1 carbon atoms.
To 12, for example, mesyl, tosyl, and the like. ), A sulfinyl group (preferably having 1 to 20 carbon atoms,
More preferably, it has 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as methanesulfinyl and benzenesulfinyl. ), A ureido group (preferably having 1 to 20 carbon atoms, more preferably having 1 to 1 carbon atoms)
6, particularly preferably 1 to 12 carbon atoms, for example, ureide, methylureide, phenylureide and the like. ), A phosphoric amide group (preferably having 1 to 2 carbon atoms)
It has 0, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, and examples thereof include diethylphosphoramide and phenylphosphoramide. ), A hydroxy group, a mercapto group, a halogen atom (for example, a fluorine atom,
Chlorine atom, bromine atom, iodine atom), cyano group, sulfo group, carboxyl group, nitro group, hydroxamic acid group, sulfino group, hydrazino group, heterocyclic group (for example, imidazolyl, pyridyl, furyl, piperidyl, morpholino, etc.) )). These substituents may be further substituted. Y is more preferably an alkyl group, an aryl group, or a halogen atom, and particularly preferably an alkyl group or a halogen atom.

In the general formula (I), L represents a divalent linking group. Specific examples of L include -CONH-, -SO _{2
NH -, - CONHSO 2 -,} - NHCONH -, - C
OO-, -O-, -S-, -CO-, -NR- (where R represents an alkyl group or an aryl group), -S
CO -, - SO -, - SO 2 -, - CH 2 -, etc. phenylene group may be mentioned, may be formed of these linking groups may further combination composite base. Hereinafter, specific examples of the divalent linking group represented by L in the general formula (I) are shown.

[0015]

Embedded image

The ballast group represented by B in the general formula (I) is a group for imparting diffusion resistance to the compound represented by the general formula (I) at the time of heat development, and preferably has a carbon number of 8 to 40 substituted or unsubstituted alkyl groups and aryl groups. More preferred are alkyl and aryl groups having 8 to 30 carbon atoms and having a hydrophilic group such as a sulfo group or a carboxyl group as a substituent. Hereinafter, specific examples of the ballast group represented by B in the general formula (I) are shown.

[0017]

Embedded image

[0018]

Embedded image

In the general formulas (I) and (II), M represents a hydrogen atom or a counter ion. Typical cations as counterions include inorganic or organic ammonium ions (eg, ammonium ion, triethylammonium ion, pyridinium ion), alkali metal ions (eg, sodium ion, potassium ion), alkaline earth metal ions (eg, , Calcium ions, magnesium ions) and other metal ions (eg, aluminum ions, zinc (II) ions, barium ions). The counter ion can be an ionic polymer, another organic compound having the opposite charge, or a metal complex ion. Preferred are ammonium ion, sodium ion, potassium ion, triethylammonium ion and pyridinium ion, and more preferred are ammonium ion, sodium ion and potassium ion. In the general formulas (I) and (II), one of M may be a hydrogen atom and the other may be a counter ion, and one counter ion of M may be different from the other counter ion. less than,
Specific examples of the compound represented by formula (I) used in the present invention will be given below, but the present invention is not limited thereto. In the column of (Y) m, “none” means that m = 0.

[0020]

[Table 1]

Q in the general formula (II) represents a group containing at least one carbon-carbon double bond. The carbon-carbon double bond part of the group represented by Q may be directly bonded to the ring, or may be bonded via a linking group represented by L in formula (II). The carbon-carbon double bond portion may further have a substituent, and examples of the substituent include a halogen atom and a carboxyl group. When Q has a dissociable group, it may form a salt. Hereinafter, specific examples of the group represented by Q in the general formula (II) are shown.

[0022]

Embedded image

Next, the general formula (II) used in the present invention
Specific examples of the polymer having a repeating unit derived from a compound represented by the following formula as a monomer will be given, but the present invention is not limited thereto. In the column of (Y) m, “none” means that m = 0.

[0024]

[Table 2]

The compounds represented by the general formulas (I) and (II) are described in, for example, The Chemical Society of Japan, Experimental Chemistry Course, 4th Edition, Vol. 22, pp. 1-43, Vol. 28, 11-. Those skilled in the art can easily synthesize them by known methods described on page 83 and the like. For example, compound I-1 can be synthesized by the following procedure. First, 197 g of 4-aminophthalic acid and 90 g of pyridine are dissolved in 2 liters of dimethylformamide and stirred under ice-cooling. Then
185 g of decanoic acid chloride was added to dimethylformamide 50
A solution dissolved in 0 ml is dropped and reacted for 2 hours. Further, 5 l of water and 5 l of ethyl acetate are added to concentrate the organic layer, and the obtained crystals are recrystallized from methanol to obtain 305 g of compound I-1. It should be noted that the procedures and amounts described here are merely examples, and it is possible to synthesize by other methods.

The polymer derived from the compound of the general formula (I) and the compound of the general formula (II) used in the present invention is:
On the image forming layer side of the heat-developable image forming material, a photosensitive layer such as an image forming layer or a non-photosensitive layer such as a protective layer can be added. Polymers derived from compounds of the compounds and of the general formula (I) (II) used in the present invention may vary depending on the desired purpose, 10 ^-4 to 1 mole shows the addition amount per Ag1 moles, preferably 10 ^{-3 to} 0.3 mol,
It is more preferable to add 10 ^{-3 to} 0.1 mol. In the heat-developable image forming material of the present invention, two or more kinds of polymers derived from the compound of the general formula (I) and the compound of the general formula (II) can be used in combination. The compound derived from the compound of the general formula (I) and the compound of the general formula (II) may be added by any method such as a solution, a powder, and a dispersion of solid fine particles. Dispersion of solid fine particles can be performed by a known micronizing means (eg, ball mill, vibrating ball mill, side mill, colloid mill, jet mill, roller mill, etc.).
Done in When dispersing the solid fine particles, a dispersing aid may be used.

The heat-developable image-forming material of the present invention is not essential, but preferably contains a super-high contrast agent. The type of the super-high contrast agent is not particularly limited, but is preferably a compound represented by the general formula (II)
Examples include the substituted alkene derivatives, substituted isoxazole derivatives or specific acetal compounds represented by I), the general formula (IV) or the general formula (V). In the following, general formula (III), general formula (IV) and general formula
(V) will be described.

First, the compound represented by formula (III) will be described in detail. In the general formula (III), R ¹ ,
R ² and R ³ each independently represent a hydrogen atom or a substituent, and Z represents an electron-withdrawing group or a silyl group. General formula
In (III), R ¹ and Z, R ² and R ³ , R ¹ and R ² , or R ³ and Z may be bonded to each other to form a cyclic structure.

When R ¹ , R ² and R ³ represent a substituent, examples of the substituent include, for example, a halogen atom (a fluorine atom, a chlorine atom, a bromine atom or an iodine atom), an alkyl group (an aralkyl group, An alkyl group, an active methine group, etc.), an alkenyl group, an alkynyl group, an aryl group, a heterocyclic group (including an N-substituted nitrogen-containing heterocyclic group) and a heterocyclic group containing a quaternized nitrogen atom ( For example, a pyridinio group), an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a carbamoyl group, a carboxy group or a salt thereof, an imino group, an imino group substituted by an N atom, a thiocarbonyl group, a sulfonylcarbamoyl group, an acylcarbamoyl group, Famoylcarbamoyl group, carbazoyl group, oxalyl group, oxamoyl group, cyano group, thiocarbamoyl group, A droxy group or a salt thereof, an alkoxy group (including a group repeatedly containing an ethyleneoxy group or a propyleneoxy group unit), an aryloxy group, a heterocyclic oxy group, an acyloxy group, an (alkoxy or aryloxy) carbonyloxy group, and a carbamoyloxy group , Sulfonyloxy group, amino group, (alkyl, aryl, or heterocycle) amino group, acylamino group, sulfonamide group, ureido group, thioureido group, imide group, (alkoxy or aryloxy)
Carbonylamino group, sulfamoylamino group, semicarbazide group, thiosemicarbazide group, hydrazino group, 4
Grade ammonio group, oxamoylamino group, (alkyl or aryl) sulfonyluureido group, acylureido group, acylsulfamoylamino group, nitro group, mercapto group, (alkyl, aryl, or heterocycle)
Thio group, acylthio group, (alkyl or aryl) sulfonyl group, (alkyl or aryl) sulfinyl group, sulfo group or a salt thereof, sulfamoyl group, acylsulfamoyl group, sulfonylsulfamoyl group or a salt thereof, phosphoryl group, phosphorus Examples thereof include a group having an acid amide or phosphate structure, a silyl group and a stannyl group. These substituents may be further substituted with these substituents.

The electron-withdrawing group represented by Z in the general formula (III) is a substituent whose Hammett's substituent constant σ _p can take a positive value, specifically, a cyano group, An alkoxycarbonyl group, an aryloxycarbonyl group,
A carbamoyl group, an imino group, an imino group substituted with an N atom, a thiocarbonyl group, a sulfamoyl group, an alkylsulfonyl group, an arylsulfonyl group, a nitro group, a halogen atom, a perfluoroalkyl group, a perfluoroalkaneamide group, a sulfonamide group, Acyl, formyl, phosphoryl, carboxy (or salt thereof), sulfo (or salt thereof), heterocyclic, alkenyl,
Examples include an alkynyl group, an acyloxy group, an acylthio group, a sulfonyloxy group, and an aryl group substituted with these electron-withdrawing groups. Here, the heterocyclic group is a saturated or unsaturated heterocyclic group, for example, a pyridyl group, a quinolyl group, a quinoxalinyl group, a pyrazinyl group, a benzotriazolyl group, an imidazolyl group, a benzimidazolyl group, a hydantoin-1-yl group , A succinimide group, a phthalimide group and the like.

The electron-withdrawing group represented by Z in the general formula (III) may further have a substituent, and the substituent may be R ¹ , R ² , R ^The same substituents as may be possessed when ³ represents a substituent are exemplified. In the general formula (III), R ¹ and Z, R ² and R ³ ,
R ¹ and R ² , or R ³ and Z may be bonded to each other to form a cyclic structure, and the cyclic structure formed at this time is a non-aromatic carbon ring or a non-aromatic heterocycle. Is a ring. Next, a preferred range of the compound represented by formula (III) will be described. Preferable examples of the silyl group represented by Z in the general formula (III) specifically include a trimethylsilyl group, a t-butyldimethylsilyl group, a phenyldimethylsilyl group, a triethylsilyl group, a triisopropylsilyl group, and a trimethylsilyldimethylsilyl group. is there.
The electron-withdrawing group represented by Z in formula (III) is preferably a group having the following number of carbon atoms, that is, a cyano group, an alkoxycarbonyl group, an aryloxycarbonyl group, a carbamoyl group, a thiocarbonyl group. An imino group, an imino group substituted with an N atom, a sulfamoyl group, an alkylsulfonyl group, an arylsulfonyl group, a nitro group, a perfluoroalkyl group, an acyl group, a formyl group,
A phosphoryl group, an acyloxy group, an acylthio group, or a phenyl group substituted with any electron-withdrawing group,
More preferably, a cyano group, an alkoxycarbonyl group, a carbamoyl group, an imino group, a sulfamoyl group, an alkylsulfonyl group, an arylsulfonyl group, an acyl group, a formyl group, a phosphoryl group, a trifluoromethyl group, or any electron-withdrawing group. It is a substituted phenyl group or the like, particularly preferably a cyano group, a formyl group, an acyl group, an alkoxycarbonyl group, an imino group or a carbamoyl group. The group represented by Z in the general formula (III) is more preferably an electron-withdrawing group.

In the general formula (III), the substituent represented by R ¹ , R ² and R ³ is preferably a total of 0 to 0 carbon atoms.
30 groups, specifically, a group having the same meaning as the electron-withdrawing group represented by Z in the above general formula (III), and an alkyl group, a hydroxy group (or a salt thereof), and a mercapto group (or a salt thereof) An alkoxy group, an aryloxy group, a heterocyclic oxy group, an alkylthio group, an arylthio group, a heterocyclic thio group, an amino group, an alkylamino group, an arylamino group,
Examples include a heterocyclic amino group, a ureido group, an acylamino group, a sulfonamide group, and a substituted or unsubstituted aryl group. Further, in the general formula (III), R
¹ is preferably an electron-withdrawing group, an aryl group, an alkylthio group, an alkoxy group, an acylamino group, a hydrogen atom or a silyl group.

When R ¹ represents an electron-withdrawing group, the following groups having preferably 0 to 30 carbon atoms in total, ie, a cyano group, a nitro group, an acyl group, a formyl group, an alkoxycarbonyl group,
An aryloxycarbonyl group, a thiocarbonyl group, an imino group, an imino group substituted with an N atom, an alkylsulfonyl group, an arylsulfonyl group, a carbamoyl group, a sulfamoyl group, a trifluoromethyl group, a phosphoryl group, a carboxy group (or a salt thereof), Or a saturated or unsaturated heterocyclic group, and a cyano group, an acyl group, a formyl group, an alkoxycarbonyl group, a carbamoyl group, an imino group, an imino group substituted with an N atom, a sulfamoyl group, a carboxy group (or a salt thereof) Or a saturated or unsaturated heterocyclic group. Particularly preferred are a cyano group, a formyl group, an acyl group, an alkoxycarbonyl group, a carbamoyl group, and a saturated or unsaturated heterocyclic group.

When R ¹ represents an aryl group, it is preferably a substituted or unsubstituted phenyl group having 6 to 30 carbon atoms, and the substituent may be any substituent.
Among them, an electron-withdrawing substituent is preferable. General formula (III)
R ¹ is more preferably a group representing an electron-withdrawing group or an aryl group. In the general formula (III), R
^The substituents represented by ² and R ³ are preferably, specifically, a group having the same meaning as the electron-withdrawing group represented by Z in the above general formula (III), an alkyl group, a hydroxy group (or a salt thereof) , A mercapto group (or a salt thereof), an alkoxy group, an aryloxy group, a heterocyclic oxy group, an alkylthio group,
Examples include an arylthio group, a heterocyclic thio group, an amino group, an alkylamino group, an anilino group, a heterocyclic amino group, an acylamino group, and a substituted or unsubstituted phenyl group. In the general formula (III), R ² and R ³ are more preferably when one of them is a hydrogen atom and the other represents a substituent. The substituent is preferably an alkyl group, a hydroxy group (or a salt thereof), a mercapto group (or a salt thereof), an alkoxy group, an aryloxy group, a heterocyclic oxy group, an alkylthio group, an arylthio group, a heterocyclic thio group, an amino group. Group, an alkylamino group, an anilino group, a heterocyclic amino group, an acylamino group (particularly a perfluoroalkaneamide group), a sulfonamide group, a substituted or unsubstituted phenyl group, or a heterocyclic group, and more preferably a hydroxy group (Or a salt thereof), a mercapto group (or a salt thereof), an alkoxy group, an aryloxy group, a heterocyclic oxy group, an alkylthio group, an arylthio group, a heterocyclic thio group, or a heterocyclic group, and particularly preferably a hydroxy group ( Or a salt thereof), an alkoxy group, or a heterocyclic group.

In the general formula (III), Z and R¹Or
Is also R^TwoAnd R^ThreeAlso preferably form a ring structure.
New The cyclic structure formed in this case is a non-aromatic carbon
A prime ring or a non-aromatic heterocycle, preferably 5
Is a 7-membered to 7-membered cyclic structure, and its total carbon number including substituents is
It is preferably from 1 to 40, more preferably from 3 to 30. General formula (II
One of the more preferable compounds represented by I)
Is a group in which Z is a cyano group, formyl group, acyl group, alkoxy
A carbonyl group, imino group, or carbamoyl group
Then R¹Represents an electron-withdrawing group or an aryl group;^TwoMa
Or R ^ThreeOne is a hydrogen atom and the other is a hydroxy
Group (or its salt), mercapto group (or its salt),
Alkoxy group, aryloxy group, heterocyclic oxy group,
Alkylthio, arylthio, heterocyclic thio,
Is a compound representing a heterocyclic group.

Further, one of the particularly preferable compounds represented by the general formula (III) is that Z and R ^{1 form a} non-aromatic 5- to 7-membered cyclic structure, Either ² or R ³ is a hydrogen atom and the other is a hydroxy group (or a salt thereof), a mercapto group (or a salt thereof), an alkoxy group, an aryloxy group, a heterocyclic oxy group, an alkylthio group, an arylthio group, A compound representing a ring thio group or a heterocyclic group. At this time, Z which forms a non-aromatic cyclic structure together with R ¹ is preferably an acyl group, a carbamoyl group, an oxycarbonyl group, a thiocarbonyl group, a sulfonyl group, and the like, and R ¹ is an acyl group, a carbamoyl group , An oxycarbonyl group, a thiocarbonyl group, a sulfonyl group, an imino group, an imino group substituted by an N atom, an acylamino group, and a carbonylthio group.

Next, the compound represented by formula (IV) will be described. As the substituent represented by R ⁴ in the general formula (IV), the same substituents as described for the substituents R ^{1 to} R ^{3 in} the general formula (III) can be mentioned. General formula (IV)
In the substituent represented by R ⁴ is preferably an electron withdrawing group or an aryl group. When R ⁴ represents an electron-withdrawing group, preferably the following groups having a total carbon number of 0 to 30, that is, a cyano group, a nitro group, an acyl group, a formyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkylsulfonyl Group, arylsulfonyl group, carbamoyl group, sulfamoyl group, trifluoromethyl group, phosphoryl group, imino group, or a saturated or unsaturated heterocyclic group, and further a cyano group, acyl group, formyl group, alkoxycarbonyl group, carbamoyl Groups, sulfamoyl groups, alkylsulfonyl groups, arylsulfonyl groups, and heterocyclic groups are preferred. Particularly preferably, a cyano group, a formyl group, an acyl group, an alkoxycarbonyl group,
It is a carbamoyl group or a heterocyclic group.

When R ⁴ represents an aryl group, it is preferably a substituted or unsubstituted phenyl group having a total of 0 to 30 carbon atoms. As the substituent, R ¹ , R ² ,
When R ³ represents a substituent, the same as those described as the substituent can be mentioned. In the general formula (IV), R
⁴ is particularly preferably a cyano group, an alkoxycarbonyl group, a carbamoyl group, a heterocyclic group, or a substituted or unsubstituted phenyl group, most preferably a cyano group,
It is a heterocyclic group or an alkoxycarbonyl group.

Next, the compound represented by the general formula (V)
explain in detail. In the general formula (V), X and Y are each
A and B independently represent a hydrogen atom or a substituent,
Independently, an alkoxy group, an alkylthio group, an alkylamido
Group, aryloxy group, arylthio group, anilino
Group, heterocyclic thio group, heterocyclic oxy group, or hetero
Represents a ring amino group. X and Y or A and B
They may combine to form a cyclic structure. In general formula (V)
In the above, the substituents represented by X and Y are represented by the general formula (II)
I) R ¹~ R^ThreeThe same as described for the substituent of
Is included. Specifically, an alkyl group (perfluoro
Roalkyl group, trichloromethyl group, etc.), aryl
Group, heterocyclic group, halogen atom, cyano group, nitro
Group, alkenyl group, alkynyl group, acyl group, formyl
Group, alkoxycarbonyl group, aryloxy carbonyl
Group, imino group, imino group substituted by N atom, carbamo
Yl, thiocarbonyl, acyloxy, acylthio
O group, acylamino group, alkylsulfonyl group, aryl
Rusulfonyl group, sulfamoyl group, phosphoryl group,
A ruboxyl group (or a salt thereof), a sulfo group (or a salt thereof)
Salt), hydroxy group (or its salt), mercapto group
(Or a salt thereof), an alkoxy group, an aryloxy group,
Heterocyclic oxy group, alkylthio group, arylthio group,
Heterocyclic thio group, amino group, alkylamino group, anili
And a heterocyclic amino group, a silyl group and the like. This
These groups may further have a substituent. And X
Y may combine with each other to form a cyclic structure,
The cyclic structure formed in this case includes a non-aromatic carbon
It may be an elementary ring or a non-aromatic hetero ring.

The substituents represented by X and Y in the general formula (V) are preferably groups having 1 to 40 carbon atoms in total, more preferably 1 to 30 carbon atoms in total, and include a cyano group and an alkoxycarbonyl group. An aryloxycarbonyl group, a carbamoyl group, an imino group, an imino group substituted with an N atom, a thiocarbonyl group, a sulfamoyl group, an alkylsulfonyl group,
Arylsulfonyl group, nitro group, perfluoroalkyl group, acyl group, formyl group, phosphoryl group, acylamino group, acyloxy group, acylthio group, heterocyclic group,
Examples thereof include an alkylthio group, an alkoxy group, and an aryl group. In the general formula (V), X and Y are more preferably a cyano group, a nitro group, an alkoxycarbonyl group, a carbamoyl group, an acyl group, a formyl group, an acylthio group,
Acylamino group, thiocarbonyl group, sulfamoyl group, alkylsulfonyl group, arylsulfonyl group, imino group, imino group substituted with N atom, phosphoryl group, trifluoromethyl group, heterocyclic group, substituted phenyl group, etc. Particularly preferably a cyano group, an alkoxycarbonyl group, a carbamoyl group, an alkylsulfonyl group, an arylsulfonyl group, an acyl group, an acylthio group,
Examples include an acylamino group, a thiocarbonyl group, a formyl group, an imino group, an imino group substituted with an N atom, a heterocyclic group, and a phenyl group substituted with any electron-withdrawing group.

X and Y are bonded to each other to form a non-aromatic carbon
May form a ring or a non-aromatic hetero ring.
Preferred. At this time, the formed annular structure has 5 to 7 members
A ring is preferable, and its total carbon number is 1 to 40, and further 3 to
30 is preferred. As X and Y forming a cyclic structure
Is an acyl group, a carbamoyl group, an oxycarbonyl group,
Thiocarbonyl group, sulfonyl group, imino group, N atom
Substituted imino group, acylamino group, carbonylthio group
Are preferred. In the general formula (V), A and B are each independently
First, an alkoxy group, an alkylthio group, an alkylamino
Group, aryloxy group, arylthio group, anilino group,
A heterocyclic thio group, a heterocyclic oxy group, or a heterocyclic a
Represents amino groups, which combine with each other to form a cyclic structure
It may be. Represented by A and B in the general formula (V)
The group preferably has 1 to 40 carbon atoms in total, more preferably
A group having 1 to 30 carbon atoms in total, and further having a substituent
You may. In the general formula (V), A and B are
More preferably when they are linked to
No. The cyclic structure formed at this time is a 5- to 7-membered non-aromatic ring
Group heterocycles are preferred, having a total carbon number of 1 to 40,
These are preferably 3 to 30. In this case, A and B are connected
For example, -O- (C
H _Two)_Two-O-, -O- (CH_Two)_Three-O-, -S- (CH
_Two)_Two-S-, -S- (CH _Two)_Three-S-,-S-Ph-S
-, -N (CH_Three)-(CH_Two)_Two-O-, -N (CH_Three)
− (CH_Two)_Two-S-, -O- (CH_Two)_Two-S-, -O-
(CH_Two)_Three-S-, -N (CH_Three) -Ph-O-,-N
(CH_Three) -Ph-S-, -N (Ph)-(CH_Two)_Two−
S- and so on.

The compounds represented by the general formulas (III), (IV) and (V) may have incorporated therein an adsorptive group that adsorbs to silver halide. Examples of such an adsorbing group include alkylthio, arylthio, thiourea, thioamide, mercapto heterocyclic, and triazole groups. 195233,
Nos. 59-200231, 59-201045, 59-201046, 59-201047, and 5
Nos. 9-201048, 59-201049, JP-A-61-170733, JP-A-61-270744, and 6
2-948, 63-234244, 63-23
Groups described in Nos. 4245 and 63-234246. These adsorbing groups to silver halide may be precursors. Examples of such a precursor include groups described in JP-A-2-285344. The compounds represented by the general formulas (III), (IV) and (V) have incorporated therein a ballast group or a polymer commonly used in immobile photographic additives such as couplers. It may be something. Particularly, those incorporating a ballast group are one of preferred examples of the present invention. The ballast group has 8 or more carbon atoms,
These groups are relatively inert to photographic properties and can be selected from, for example, alkyl groups, aralkyl groups, alkoxy groups, phenyl groups, alkylphenyl groups, phenoxy groups, alkylphenoxy groups, and the like. Examples of the polymer include those described in JP-A-1-100530.

The compounds represented by the general formulas (III), (IV) and (V) contain a cationic group (specifically, a group containing a quaternary ammonium group,
A nitrogen-containing heterocyclic group containing a graded nitrogen atom, etc.), a group containing a repeating unit of an ethyleneoxy group or a propyleneoxy group, (alkyl, aryl, or heterocycle)
It may contain a thio group or a dissociable group that can be dissociated by a base (carboxy group, sulfo group, acylsulfamoyl group, carbamoylsulfamoyl group, etc.). Particularly, a group containing a group containing a repeating unit of an ethyleneoxy group or a propyleneoxy group or a group containing an (alkyl, aryl, or heterocyclic) thio group is one of preferred examples of the present invention. Specific examples of these groups include, for example, JP-A-7-234471 and JP-A-5-33.
3466, JP-A-6-19032, JP-A-6-19
031, JP-A-5-45761, U.S. Pat.
4,365, U.S. Pat. No. 4,988,604, JP-A-3-259240, JP-A-7-5610, and JP-A-7
-244348, German Patent 4006032 and the like.

Specific examples of the compounds represented by the general formulas (III), (IV) and (V) are shown below. However, the present invention is not limited to the following compounds.

[0045]

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[0046]

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[0047]

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The compounds represented by the general formulas (III), (IV) and (V) can be prepared by using water or a suitable organic solvent such as alcohols (methanol, ethanol, propanol, fluorinated alcohol), ketone (Acetone, methyl ethyl ketone), dimethylformamide, dimethylsulfoxide, methylcellosolve and the like. Also, by an already well-known emulsification dispersion method, an oil such as dibutyl phthalate, tricresyl phosphate, glyceryl triacetate or diethyl phthalate, and an auxiliary solvent such as ethyl acetate or cyclohexanone are dissolved and mechanically emulsified and dispersed. An object can be prepared and used. Alternatively, by a method known as a solid dispersion method, a compound represented by the general formula (III):
Powders of the compounds represented by the general formulas (IV) and (V) are mixed in a suitable solvent such as water in a ball mill, a colloid mill,
Alternatively, it can be dispersed and used by ultrasonic waves.

The compounds represented by the general formulas (III), (IV) and (V) may be used in a layer on the image forming layer side with respect to the support, that is, the image forming layer or another layer on the layer side. It may be added to any layer, but is preferably added to the image forming layer or a layer adjacent thereto. The addition amount of the compounds represented by the general formulas (III), (IV) and (V) is preferably 1 × 10 ^-6 to 1 mol per mol of silver.
1 × 10 ^{−5 to} 5 × 10 ⁻¹ mol is more preferable, and 2 × 10 ⁻⁵
Most preferably ^{-5 to} 2 × 10 ^-1 mol.

The compounds represented by formulas (III), (IV) and (V) can be easily synthesized by known methods. For example, US Pat.
No. 515, U.S. Pat. No. 5,635,339, U.S. Pat. No. 5,654,130, International Publication WO 97/34196.
Or Japanese Patent Application No. 9-354107, 9-3
The compound can be synthesized with reference to the methods described in Japanese Patent Application No. 09813 and Japanese Patent Application No. 9-272002. The compounds represented by the general formulas (III), (IV) and (V) may be used alone or in combination of two or more. In addition to the above, US Pat. No. 5,545,515, US Pat. No. 5,635,339, US Pat.
No. WO97 / 34196, U.S. Pat.
No. 86,228;
No. 228888, Japanese Patent Application No. 9-273935, Japanese Patent Application No. 9-354107, Japanese Patent Application No. 9-309813, Japanese Patent Application No. 9-296174, Japanese Patent Application No. 9-282564, and Japanese Patent Application No. 9-2722002. No., Japanese Patent Application No. 9-272003,
Compounds described in Japanese Patent Application No. 9-332388 may be used in combination.

Further, in the present invention, Japanese Patent Application Laid-Open No. 10-3
The hydrazine derivatives described in JP-A-39932 and JP-A-10-161270 can also be used in combination. Further, the following hydrazine derivatives can be used in combination. That is, a compound represented by (Chemical Formula 1) described in JP-B-6-77138, specifically, page 3,
Compounds described on page 4. A compound represented by the general formula (I) described in JP-B-6-93082.
Compounds 1-38 on pages 18-18. JP-A-6-23
No. 0497, compounds represented by the general formulas (4), (5) and (6).
Compounds 4-1 to 4-10 described on page 5, page 26,
Compounds 5-1 to 5-42 described on pages 28 to 36, and compounds 6-1 to 6- described on pages 39 and 40
7. Compounds represented by formulas (1) and (2) described in JP-A-6-289520, specifically, compounds 1-1) to 1-17 described on pages 5 to 7 of the same publication. ) And 2-1). Compounds represented by (Chemical Formula 2) and (Chemical Formula 3) described in JP-A-6-313936, specifically, compounds described on pages 6 to 19 of the same. JP-A-6-3139
A compound represented by Chemical Formula 1 described in No. 51, specifically, a compound described on pages 3 to 5 of the same publication. JP-A-7-561
Compounds represented by general formula (I) described in No. 0, specifically, Compounds 1-1 to 1-3 described on pages 5 to 10 of the same publication
8. Compounds represented by formula (II) described in JP-A-7-77783, specifically, compounds II-1 to II-102 described on pages 10 to 27 of the same. JP-A-7-10442
Compounds represented by general formula (H) and general formula (Ha) described in No. 6, specifically, compounds H-1 to H-44 described on pages 8 to 15 of the same publication. A compound described in European Patent 713131A, which has an anionic group or a nonionic group that forms an intramolecular hydrogen bond with a hydrogen atom of hydrazine in the vicinity of a hydrazine group. Formula (B), Formula (C), Formula (D),
Compounds represented by formulas (E) and (F), specifically, compounds N-1 to N-30 described in the publication. A compound represented by the general formula (1) described in European Patent 713131A, and specifically, compounds D-1 to D- described in the publication.
55. In addition, `` Known technologies (1-207) published on March 22, 1991
Various hydrazine derivatives as described on pages 25 to 34 of Aztec. Compounds D-2 and D-39 of JP-A-62-86354 (pages 6 to 7).

These hydrazine derivatives are dissolved in water or a suitable organic solvent such as alcohols (methanol, ethanol, propanol, fluorinated alcohol), ketones (acetone, methyl ethyl ketone), dimethylformamide, dimethyl sulfoxide, methylcellosolve, etc. Can be used. Also, by an already well-known emulsification dispersion method, an oil such as dibutyl phthalate, tricresyl phosphate, glyceryl triacetate or diethyl phthalate, and an auxiliary solvent such as ethyl acetate or cyclohexanone are dissolved and mechanically emulsified and dispersed. An object can be prepared and used. Alternatively, by a method known as a solid dispersion method, a powder of a hydrazine derivative is put into water using a ball mill, a colloid mill,
Alternatively, it can be dispersed and used by ultrasonic waves.

These hydrazine derivatives may be added to the layer on the image forming layer side with respect to the support, that is, the image forming layer or any other layer on the layer side, but may be added to the image forming layer or a layer adjacent thereto. It is preferable to add. The addition amount of these hydrazine derivatives is 1 × 10 ⁻⁶ to 1 mol of silver.
1 mol is preferable, 1 * 10 < ^-5 > to 5 * 10 <^-1> mol is more preferable, and 2 * 10 < ^-5 > to 2 * 10 <^-1> mol is most preferable. Further, acrylonitriles described in U.S. Pat. No. 5,545,515, specifically, CN-1 to CN-13 and the like can be used as a super-high contrast agent.

Further, the present invention provides a method for forming a super-high contrast image.
A high contrast accelerator can be used in combination with the above-mentioned super-high contrast agent. For example, the amine compounds described in U.S. Patent No. 5,545,505, specifically AM-1 to AM-5, and 5,545,507
, Specifically HA-1 to HA
Hydrazine compounds described in JP-A-5-558983, specifically CA-1 to CA-6, onium salts described in JP-A-9-297368, specifically A-1 to A-42, B-1 to B-
27, C-1 to C-14 and the like can be used. The synthesis method, addition method, addition amount, and the like of the above-mentioned super-high contrast agent and these high-contrast accelerators can be performed as described in each of the cited patents.

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

In a photothermographic material using an organic silver salt, a wide range of reducing agents are disclosed in JP-A-46-6074 and JP-A-47-1238.
47-33621, 49-46427, 49-115540, 50-14
No. 334, No. 50-36110, No. 50-147711, No. 51-32632,
No. 51-1023721, No. 51-32324, No. 51-51933, No. 52-8
4727, 55-108654, 56-146133, 57-82828
No. 57-82829, JP-A-6-3793, U.S. Pat.
No. 86, No. 3,679,426, No. 3,751,252, No. 3,751,255
Nos. 3,761,270, 3,782,949, 3,839,048,
3,928,686, 5,464,738, German patent 2321328,
It is disclosed in European Patent No. 692732 and the like. For example, phenylamide oxime, 2-thienylamide oxime and
Amide oximes such as p-phenoxyphenylamide oxime; azines such as 4-hydroxy-3,5-dimethoxybenzaldehyde azine; combinations of 2,2′-bis (hydroxymethyl) propionyl-β-phenylhydrazine with ascorbic acid A combination of such an aliphatic carboxylic acid aryl hydrazide and ascorbic acid; a combination of polyhydroxybenzene and hydroxylamine, reductone and / or hydrazine (eg, hydroquinone and bis (ethoxyethyl) hydroxylamine, piperidinohexose reductone Or a combination of formyl-4-methylphenylhydrazine, etc.); phenylhydroxamic acid, p
Hydroxamic acids such as -hydroxyphenylhydroxamic acid and β-alinine hydroxamic acid; combinations of azines with sulfonamidophenols (eg, phenothiazine and 2,6-dichloro-4-benzenesulfonamidophenol); ethyl-α-cyano Α-cyanophenylacetic acid derivatives such as 2-methylphenylacetate and ethyl-α-cyanophenylacetate; 2,2′-dihydroxy-1,1′-binaphthyl, 6,6′-dibromo-2,2′-dihydroxy Bis-β-naphthol as exemplified by -1,1′-binaphthyl and bis (2-hydroxy-1-naphthyl) methane; bis-β-naphthol and 1,3-dihydroxybenzene derivatives (eg, 2,4
-Dihydroxybenzophenone or 2 ', 4'-dihydroxyacetophenone); 3-methyl-1-phenyl
5-pyrazolone, such as -5-pyrazolone; reductones as exemplified by dimethylaminohexose reductone, anhydrodihydroaminohexose reductone and anhydrodihydropiperidone hexose reductone;
Sulfonamidophenol reducing agents such as 2,6-dichloro-4-benzenesulfonamidophenol and p-benzenesulfonamidophenol; 2-phenylindane-1,3-
Dione and the like; chromanes such as 2,2-dimethyl-7-t-butyl-6-hydroxychroman; 1,4-dihydropyridines such as 2,6-dimethoxy-3,5-dicarbethoxy-1,4-dihydropyridine; Bisphenols (e.g., bis (2-hydroxy-3
-t-butyl-5-methylphenyl) methane, 2,2-bis (4-hydroxy-3-methylphenyl) propane, 4,4-ethylidene-
Bis (2-t-butyl-6-methylphenol), 1,1-bis (2-hydroxy-3,5-dimethylphenyl) -3,5,5-trimethylhexane and 2,2-bis (3,5 -Dimethyl-4-hydroxyphenyl) propane, etc.); ascorbic acid derivatives (for example,
And aldehydes and ketones such as benzyl and biacetyl; 3-pyrazolidone and certain indan-1,3-diones; chromanol (such as tocopherol).

The reducing agent used in the present invention may be added by any method such as a solution, a powder, and a dispersion of solid fine particles. Solid fine particle dispersion is known micronization means (for example, ball mill, vibrating ball mill, sand mill, colloid mill,
Jet mill, roller mill, etc.). Also,
When dispersing the solid fine particles, a dispersing aid may be used.

The silver halide emulsions and / or organic silver salts used in the present invention are further protected against the formation of additional fog by known antifoggants, stabilizer precursors, and sensitivity during storage in stock. Can be stabilized. Suitable antifoggants, stabilizers and stabilizer precursors that can be used alone or in combination are the thiazonium salts described in U.S. Patent Nos. 2,131,038 and 2,694,716; Azaindene, U.S. Pat.
728,663 mercury salt, U.S. Pat.No. 3,287,135 urazole, U.S. Pat.No. 3,235,652 sulfocatechol, British Patent No.
No. 405, polyvalent metal salts, U.S. Pat.No. 3,220,839, thyuronium salts, and U.S. Pat. Halogen-substituted organic compounds described in 4,442,202, U.S. Pat.
No. 7 and No. 4,137,079, No. 4,138,365 and No.
No. 4,459,350, and U.S. Pat.
And the phosphorus compounds described in JP-A-411,985.

The antifoggant preferably used in the present invention is an organic halide.
No., No. 50-120328, No. 51-121332, No. 54-58022, No.
56-70543, 56-99335, 59-90842, 61-12964
No. 2, 62-129845, JP-A-6-208191, 7-5621,
Nos. 7-2781, 8-15809, U.S. Pat.No. 5,340,712,
Compounds such as those disclosed in US Pat. Nos. 5,369,000 and 5,464,737 can be mentioned. Although not required to practice the present invention, it may be advantageous to add a mercury (II) salt as an antifoggant to the emulsion layer. Preferred mercury (II) salts for this purpose are mercury acetate and mercury bromide.

The heat-developable image forming material of the present invention may contain benzoic acids for the purpose of increasing the sensitivity and preventing fog.
The benzoic acids may be any benzoic acid derivative, but examples of preferred structures include U.S. Pat.
No. 2,160, JP-A-9-329863, JP-A-9-32
No. 9864, and compounds described in JP-A-9-281637. The benzoic acid may be added to any part of the recording material, but it is preferable to add the benzoic acid to the layer having the photosensitive layer which is the image forming layer, and it is preferable to add the benzoic acid to the organic silver salt-containing layer. preferable. The benzoic acid may be added at any time during the preparation of the coating solution, and when added to the organic silver salt-containing layer, may be added at any time from the preparation of the organic silver salt to the coating solution, but after the preparation of the organic silver salt. To just before application. The benzoic acid may be added by any method such as powder, solution, and fine particle dispersion. Further, it may be added as a solution mixed with other additives such as a sensitizing dye, a reducing agent and a color tone agent. The amount of benzoic acid added may be any amount, but is preferably 1 micromol or more and 2 mol or less per 1 mol of silver.
More preferably, the amount is from mmol to 0.5 mol.

The heat-developable image-forming material of the present invention preferably contains, but is not essential to, photosensitive silver halide. Hereinafter, the photosensitive silver halide used in the present invention will be described in detail. The photosensitive silver halide used in the present invention is not particularly limited as a halogen composition, and silver chloride, silver chlorobromide, silver bromide, silver iodobromide, and silver iodochlorobromide can be used. The distribution of the halogen composition in the grains may be uniform, the halogen composition may be changed stepwise, or may be changed continuously.
Further, silver halide grains having a core / shell structure can be preferably used. The structure is preferably 2
Core / shell particles having a ５5-fold structure, more preferably a 2- to 4-fold structure, can be used. A technique for localizing silver bromide on the surface of silver chloride or silver chlorobromide grains can also be preferably used.

The method of forming the photosensitive silver halide used in the present invention is well known in the art, and is described, for example, in Research Disclosure No. 17029, June 1978, and US Pat. No. 3,700,458. Can be used. Specific methods that can be used in the present invention include a method of converting a part of the silver of the organic silver salt to a photosensitive silver halide by adding a halogen-containing compound to the prepared organic silver salt, gelatin. Alternatively, a method in which a silver supply compound and a halogen supply compound are added to another polymer solution to prepare photosensitive silver halide grains and mixed with an organic silver salt can be used. In the present invention, the latter method can be preferably used. The grain size of the photosensitive silver halide is preferably small for the purpose of suppressing the white turbidity after image formation, specifically, 0.20 μm or less, more preferably 0.01 μm or more and 0.15 μm or less, and still more preferably 0.02 μm or more. 0.12 μm or less is preferred.
Here, the grain size means the length of the edge of the silver halide grain when the silver halide grain is a cubic or octahedral so-called normal crystal. In the case where the silver halide grains are tabular grains, the diameter refers to the diameter when converted into a circular image having the same area as the projected area of the main surface. In the case of other than normal crystals, for example, in the case of spherical grains, rod-shaped grains, etc., it refers to the diameter of a sphere equivalent to the volume of silver halide grains.

The shape of the silver halide grains is cubic,
Octahedral, tabular particles, spherical particles, rod-like particles, potato-like particles and the like can be mentioned. In the present invention, cubic particles and tabular particles are particularly preferable. When tabular silver halide grains are used, the average aspect ratio is preferably 100: 1 to 2: 1, more preferably 50: 1 to 3: 1. Further, grains having rounded corners of silver halide grains can also be preferably used. The surface index (mirror index) of the outer surface of the photosensitive silver halide grains is not particularly limited, but the spectral sensitizing efficiency when a spectral sensitizing dye is adsorbed is high.
The proportion occupied by the [100] plane is preferably high. The ratio is preferably 50% or more, more preferably 65% or more,
80% or more is more preferable. The Miller index [100] plane ratio was determined by T. Tani; J. Imaging Sci., 29, 165 (1985), which utilizes the adsorption dependence of [111] and [100] planes on the adsorption of sensitizing dyes. It can be determined by the method described.

The light-sensitive silver halide grains used in the present invention are selected from groups VII and VIII (groups 7 to 7) of the periodic table.
It preferably contains a metal of Group 10) or a metal complex. Rhodium, rhenium, ruthenium, osmium and iridium are preferred as the metal of Group VII or VIII of the periodic table or the central metal of the metal complex. One type of these metal complexes may be used, or two or more types of complexes of the same metal and different metals may be used in combination. The preferred content is in the range of 10 ^-9 mol to 10 ^-2 mol, preferably 10 ^-8 mol to 10 ^-4 mol, per mol of silver. As a specific structure of the metal complex, a metal complex having a structure described in JP-A-7-225449 or the like can be used.

As the rhodium compound preferably used in the present invention, a water-soluble rhodium compound can be used. For example, a rhodium (III) halide compound or a rhodium complex salt having a ligand such as halogen, amines, oxalato, etc., for example, hexachlororhodium (III) complex salt, pentachloroacolodium (III) complex salt,
Tetrachlorodiachodium (III) complex salt, hexabromorhodium (III) complex salt, hexaamminerhodium (II)
I) complex salts and trizalatrodium (III) complex salts. These rhodium compounds are used by dissolving them in water or a suitable solvent. A method generally used for stabilizing a solution of the rhodium compound, that is, an aqueous solution of hydrogen halide (for example, hydrochloric acid, bromic acid, fluoride, etc.) Hydrogen acid, etc.) or alkali halides (eg KCl, NaC
l, KBr, NaBr, etc.) can be used. Instead of using water-soluble rhodium, it is also possible to add and dissolve other silver halide grains doped with rhodium during the preparation of silver halide.

The addition amount of these rhodium compounds is
1 × 10 per mole of silver halide^-8Mol ~ 5 x 10^-6Mole of
The range is preferably, particularly preferably 5 × 10^-8Mol ~ 1x
10 ^-6Is a mole. The addition of these compounds is
Steps during the production of silver halide emulsion grains and before coating the emulsion
Can be suitably performed, but in particular,
And preferably incorporated into silver halide grains.
No.

Rhenium, ruthenium and osmium preferably used in the present invention are described in JP-A-63-2042 and JP-A-1-2859.
It is added in the form of a water-soluble complex salt described in JP-A Nos. 41, 2-20852, 2-20855 and the like. Particularly preferred is a six-coordinate complex represented by the following formula. [ML ₆ ] ⁿ -where M represents Ru, Re, or Os, L represents a ligand, and n represents 0, 1, 2, 3, or 4. In this case, the counter ion is not important and ammonium or alkali metal ions are used.

Preferred ligands include halide ligands, cyanide ligands, cyanide ligands, nitrosyl ligands, thionitrosyl ligands and the like.
Examples of specific complexes used in the present invention are shown below, but the present invention is not limited thereto. [ReCl ₆ ] ^3- [ReBr ₆ ] ^3- [ReCl ₅ (NO)] ^2- [Re (NS) Br ₅ ] ^2- [Re (NO) (CN) ₅ ] ^2- [Re (O) ₂ ( CN) ₄ ] ^3- [RuCl ₆ ] ^3- [RuCl ₄ (H ₂ O) ₂ ] ^- [RuCl ₅ (H ₂ O)] ^2- [RuCl ₅ (NO)] ^2- [RuBr ₅ (NS)] _{^{2- [Ru (CO) 3 Cl}} 3] 2- [Ru (CO) Cl 5] 2- [Ru (CO) Br 5] 2- [OsCl 6] 3- [OsCl 5 (NO)] 2- [Os (NO) (CN) ₅ ] ^2- [Os (NS) Br ₅ ] ^2- [Os (O) ₂ (CN) ₄ ] ^4-

The addition amount of these compounds is 1
It is preferably in the range of 1 × 10 ⁻⁹ mol to 1 × 10 ⁻⁵ mol per mol, particularly preferably 1 × 10 ⁻⁸ mol to 1 × 10 ⁻⁶ mol. These compounds can be appropriately added at the time of the production of silver halide emulsion grains and at each stage before coating the emulsion, but it is particularly preferable to add them at the time of emulsion formation and incorporate them into the silver halide grains. . In order to add these compounds during silver halide grain formation and incorporate them into silver halide grains, a metal complex powder or an aqueous solution dissolved together with NaCl or KCl is added to a water-soluble salt or a water-soluble salt during grain formation. A method in which silver halide grains are added to a neutral halide solution, or a third solution is added when a silver salt and a halide solution are simultaneously mixed, and silver halide grains are prepared by a three-solution simultaneous mixing method, or a grain formation method. There is a method in which a required amount of an aqueous solution of a metal complex is charged into a reaction vessel. In particular, a method of adding a powder or an aqueous solution dissolved together with NaCl and KCl to a water-soluble halide solution is preferable. In order to add the metal complex to the surface of the particles, a required amount of an aqueous solution of a metal complex can be charged into the reaction vessel immediately after the formation of the particles, during or during the physical ripening, or at the time of chemical ripening.

Various compounds can be used as the iridium compound preferably used in the present invention. Examples thereof include hexachloroiridium, hexaammineiridium, trioxalatoiridium, hexacyanoiridium, and pentachloronitrosyliridium. These iridium compounds are used after being dissolved in water or a suitable solvent. However, a method generally used for stabilizing a solution of the iridium compound, that is, an aqueous hydrogen halide solution (for example, hydrochloric acid, bromic acid, hydrofluoric acid) is used. Etc.) or alkali halides (eg KCl, NaCl, KBr, NaBr, etc.)
Can be used. Instead of using water-soluble iridium, it is also possible to add and dissolve another iridium-doped silver halide grain during silver halide preparation.

The silver halide grains used in the present invention may further include cobalt, iron, nickel, chromium, palladium,
It may contain metal atoms such as platinum, gold, thallium, copper and lead. For compounds of cobalt, iron, chromium and ruthenium, hexacyano metal complexes can be preferably used. Specific examples include ferricyanate ion, ferrocyanate ion, hexacyanocobaltate ion,
Examples include, but are not limited to, hexacyanochromate ions, hexacyanoruthenate ions, and the like. The metal complex in the silver halide may be contained uniformly, may be contained in the core portion at a high concentration, or may be contained in the shell portion at a high concentration, and there is no particular limitation. The metal is 1 × 10 ^-9 to 1 × 1 per mol of silver halide.
^0-4 moles are preferred. Further, in order to contain the above-mentioned metal, a metal salt in the form of a single salt, a double salt or a complex salt can be added at the time of preparing particles. The photosensitive silver halide grains can be desalted by washing with a method known in the art such as a noodle method or a flocculation method, but in the present invention, it may or may not be desalted.

The silver halide emulsion used in the present invention is
It is preferable that learning is sensitized. As a method of chemical sensitization
Are sulfur sensitization, selenium sensitization, tellurium sensitization, precious metals
A known method such as a sensitization method can be used.
Used alone or in combination. Use in combination
For example, sulfur sensitization and gold sensitization, sulfur sensitization
Method, selenium sensitization method and gold sensitization method, sulfur sensitization method and tellurium sensitization
Method and gold sensitization method, sulfur sensitization method and selenium sensitization method and tellurium sensitization
Method and gold sensitization method are preferred. Sulfur used in the present invention
Sensitization is usually carried out by adding a sulfur sensitizer to a high
This is carried out by stirring the emulsion at room temperature for a certain period of time. sulfur
As the sensitizer, known compounds can be used.
For example, in addition to sulfur compounds contained in gelatin, various
Sulfur compounds such as thiosulfates, thioureas, thiazols
And rhodanines can be used. preferable
Sulfur compounds are thiosulfates and thiourea compounds. Sulfuric acid
The amount of yellow sensitizer added depends on the pH, temperature and halogenation during chemical ripening.
Changes under various conditions such as the size of silver halide grains
Is 10 per mole of silver halide. ^-7-10^-2In mole
And more preferably 10^-Five-10^-3Is a mole.

As the selenium sensitizer used in the present invention, known selenium compounds can be used. That is, it is usually carried out by adding an unstable and / or non-unstable selenium compound and stirring the emulsion at a high temperature of 40 ° C. or higher for a certain time. As unstable selenium compounds, JP-B-44-15748, JP-B-43-13489, JP-A-4-25832,
The compounds described in JP-A Nos. 4-109240 and 4-324855 can be used. In particular, the general formula (VIII) in JP-A-4-324855
It is preferable to use the compound represented by (IX).
The tellurium sensitizer used in the present invention is a compound which forms silver telluride which is presumed to be a sensitizing nucleus on the surface or inside of silver halide grains. The formation rate of silver telluride in the silver halide emulsion can be tested by the method described in JP-A-5-313284. Examples of tellurium sensitizers include diacyl tellurides, bis (oxycarbonyl) tellurides, bis (carbamoyl) tellurides, diacyl tellurides, bis (oxycarbonyl) ditellurides,
(Carbamoyl) ditellurides, compounds having a P = Te bond, tellurocarboxylates, Te-organyltellurocarboxylates, di (poly) tellurides, tellurides, tellurols, telluroacetals, tellurosulfonates, Compounds having a P-Te bond, Te-containing heterocycles, tellurocarbonyl compounds, inorganic tellurium compounds, colloidal tellurium, and the like can be used. In particular,
U.S. Patent Nos. 1,623,499, 3,320,069, and 3,772,03
No. 1, UK Patent Nos. 235, 211, 1,121,496, 1,295,
No. 462, No. 1,396,696, Canadian Patent No. 800,958, JP-A-4-204640, JP-A-4-71341, JP-A-4-333043, JP-A-5-303
No. 157, Journal of Chemical Society Chemical Communication (J. Chem. Soc. Chem. Co.)
mmun.) 635 (1980), ibid 1102 (1979), ibid 645 (1979),
Journal of Chemical Society Perkin Transaction (J.Chem.Soc.Perkin.Trans.) 1,
2191 (1980), edited by S. Patai, The Chemistry of Organic Sereniu
m and Tellunium Compounds), Vol. 1 (1986), Vol. 2 (1
987) can be used. In particular,
Compounds represented by formulas (II), (III) and (IV) in 5-313284 are preferred.

[0074] The amount of the selenium and tellurium sensitizers used in the present invention, the silver halide grains to be used, but the chemical ripening condition and the like and, generally, per mol of silver halide 10 ^-8 to 10 ^-2 mol, Preferably about 10 ^-7 to 10 ^-3 mol is used. The conditions of the chemical sensitization in the present invention are not particularly limited, but the pH is 5 to 8, the pAg is 6 to 11, preferably 7 to 10, and the temperature is 40 to 95 ° C, preferably 45 to 45 ° C. 85 ° C. Examples of the noble metal sensitizer used in the present invention include gold, platinum, palladium, and iridium, and gold sensitization is particularly preferable. Specific examples of the gold sensitizer used in the present invention include chloroauric acid, potassium chloroaurate, potassium aurithiocyanate, and gold sulfide, and 10 ^-7 to 10 ^-2 mol per mol of silver halide. Degrees can be used.

In the silver halide emulsion used in the present invention, a cadmium salt, a sulfite, a lead salt, a thallium salt and the like may coexist in the process of forming silver halide grains or physical ripening. In the present invention, reduction sensitization can be used. Specific compounds of the reduction sensitization method include, as well as ascorbic acid, thiourea dioxide, for example, stannous chloride,
Aminoiminomethanesulfinic acid, hydrazine derivatives,
Borane compounds, silane compounds, polyamine compounds and the like can be used. Also, adjust the pH of the emulsion to 7 or more or pAg.
Reduction sensitization can be achieved by ripening while keeping the temperature at 8.3 or less. Further, reduction sensitization can be achieved by introducing a single addition portion of silver ion during grain formation.

The silver halide emulsion used in the present invention may be added with a thiosulfonic acid compound according to the method described in EP 293,917. The silver halide emulsion in the heat-developable image forming material of the present invention may be only one kind,
Two or more (for example, those having different average grain sizes, different halogen compositions, different crystal habits, and different chemical sensitization conditions) may be used in combination. The amount of the photosensitive silver halide is preferably 0.01 mol or more and 0.5 mol or less, more preferably 0.02 mol or more and 0.3 mol or less, and 0.03 mol or more and 0.25 mol or less per 1 mol of the organic silver salt.
Molar or less is particularly preferred. Regarding the mixing method and the mixing conditions of the separately prepared photosensitive silver halide and organic silver salt, the prepared silver halide particles and organic silver salt were mixed with a high-speed stirrer, a ball mill, a sand mill, a colloid mill, a vibration mill, and a homogenizer. And the like, or a method of preparing an organic silver salt by mixing photosensitive silver halide prepared at any timing during the preparation of the organic silver salt. There is no particular limitation as long as it appears in.

The heat-developable image forming material of the present invention contains a reducible silver salt. Organic silver salts, which can be used as reducible silver salts, are relatively stable to light, but in the presence of an exposed photocatalyst (such as a latent image of photosensitive silver halide) and a reducing agent. It is a silver salt that forms a silver image when heated to a temperature of ℃ or more. The organic silver salt can be any organic substance including a source capable of reducing silver ions. Silver salts of organic acids, especially (with 10-30, preferably 15-28 carbon atoms)
Silver salts of long chain fatty carboxylic acids are preferred. Ligand 4.0-1
Complexes of organic or inorganic silver salts having a complex stability constant in the range of 0.0 are also preferred. The silver donor material can preferably make up about 5-70% by weight of the imaging layer. Preferred organic silver salts include silver salts of organic compounds having a carboxyl group. Examples of these include, but are not limited to, silver salts of aliphatic carboxylic acids and silver salts of aromatic carboxylic acids. Preferred examples of the silver salt of an aliphatic carboxylic acid include:
Silver behenate, silver arachidate, silver stearate, silver oleate, silver laurate, silver caproate, silver myristate, silver palmitate, silver maleate, silver fumarate, silver tartrate, silver linoleate, silver butyrate and Including silver camphorate, mixtures thereof and the like.

Silver salts of compounds containing a mercapto group or a thione group and derivatives thereof can also be used.
Preferred examples of these compounds include 3-mercapto-4
-Phenyl-1,2,4-triazole silver salt, 2-mercaptobenzimidazole silver salt, 2-mercapto-5-aminothiadiazole silver salt, 2- (ethylglycolamide) benzothiazole silver salt, S- Silver salts of thioglycolic acid such as silver salts of alkylthioglycolic acid (where the alkyl group has 12 to 22 carbon atoms), silver salts of dithiocarboxylic acids such as silver salts of dithioacetic acid, silver salts of thioamides, 5 Silver salt of -carboxyl-1-methyl-2-phenyl-4-thiopyridine, silver salt of mercaptotriazine, silver salt of 2-mercaptobenzoxazole, silver salt described in U.S. Pat.No. 4,123,274, for example, 3-amino-5 Silver salts of 1,2,4-mercaptothiazole derivatives such as -benzylthio-1,2,4-thiazole silver salt, 3- (3-carboxyethyl) -4- described in U.S. Pat.No. 3,301,678
Includes silver salts of thione compounds such as silver salt of methyl-4-thiazoline-2-thione. Further, compounds containing an imino group can also be used. Preferred examples of these compounds include silver salts of benzotriazole and derivatives thereof,
For example, silver salts of benzotriazole such as silver methylbenzotriazole, silver salts of halogen-substituted benzotriazole such as silver 5-chlorobenzotriazole, U.S. Pat.
0,709, 1,2,4-triazole or 1-H-
Includes silver salts of tetrazole, silver salts of imidazole and imidazole derivatives, and the like. For example, U.S. Pat.
Various silver acetylide compounds as described in No. 1 and 4,775,613 can also be used.

The shape of the organic silver salt that can be used in the present invention is not particularly limited, but a needle crystal having a short axis and a long axis is preferable. In the present invention, the minor axis is 0.01 μm or more and 0.2 μm or more.
0 μm or less, major axis of 0.10 μm or more and 5.0 μm or less, minor axis of 0.01 μm or more and 0.15 μm or less, and major axis of 0.10 μm or more and 4.0 μm or less are more preferred. The particle size distribution of the organic silver salt is preferably monodispersed. Monodisperse and the minor axis, the percentage of the value obtained by dividing the standard deviation of the length of each major axis by each minor axis, major axis is preferably 100% or less, more preferably 80% or less,
More preferably, it is 50% or less. The shape of the organic silver salt can be measured from a transmission electron microscope image of the organic silver salt dispersion. As another method of measuring the monodispersity, there is a method of determining the standard deviation of the volume-weighted average diameter of the organic silver salt, the percentage of the value divided by the volume-weighted average diameter (coefficient of variation) is preferably 100% or less, more Preferably 80% or less,
More preferably, it is 50% or less. As a measuring method, for example, the particle size (volume weighted average diameter) obtained by irradiating a laser beam to an organic silver salt dispersed in a liquid and obtaining an autocorrelation function with respect to a time change of fluctuation of the scattered light is obtained. Can be. The organic silver salt that can be used in the present invention is preferably desalted. The desalting method is not particularly limited, and a known method can be used. A known filtration method such as centrifugal filtration, suction filtration, ultrafiltration, or floc-forming water washing by a coagulation method can be preferably used.

In the present invention, in order to obtain an organic silver salt solid dispersion having a high S / N, a small particle size and no aggregation, an organic silver salt which is an image forming medium and a photosensitive silver salt are substantially contained. It is preferable to use a dispersion method in which a water dispersion liquid which is not included in the liquid is converted into a high-speed stream and then the pressure is reduced.

After passing through these steps, the mixture is mixed with an aqueous solution of a photosensitive silver salt to produce a coating solution for a photosensitive image forming medium. When a heat-developable image-forming material is prepared using such a coating solution, a haze is low, and a low-fogging and high-sensitivity heat-developable image-forming material can be obtained. On the other hand, when the photosensitive silver salt is coexistent when the light is converted into a high-pressure and high-speed flow and dispersed, the fog increases and the sensitivity is liable to decrease remarkably. Also,
When an organic solvent is used instead of water as a dispersion medium, haze increases, fog increases, and sensitivity tends to decrease. On the other hand, instead of mixing the photosensitive silver salt aqueous solution,
If a conversion method is used in which a part of the organic silver salt in the dispersion is converted to a photosensitive silver salt, the sensitivity tends to decrease. In the above, the high pressure, the aqueous dispersion is dispersed and converted to high speed, is substantially free of photosensitive silver salt, the content is 0.1 mol% based on the non-photosensitive organic silver salt In the following, the photosensitive silver salt was not positively added.

In the present invention, the solid dispersion apparatus and the technique used for carrying out the dispersion method as described above are described in, for example, “Dispersion Rheology and Dispersion Technology” (Toshio Kajiuchi and Hiroki Usui, 1991, Shinzansha Publishing Co., Ltd., p357
-P403), "The 24th Progress of Chemical Engineering", edited by The Society of Chemical Engineers, Tokai Branch, 1990, Maki Shoten, p184-p185),
Although detailed in the dispersing method of the present invention, the aqueous dispersion containing at least an organic silver salt is pressurized by a high-pressure pump or the like and sent into a pipe, and then passed through a narrow slit provided in the pipe, Thereafter, the dispersion is finely dispersed by causing an abrupt pressure drop in the dispersion.

The high-pressure homogenizer to which the present invention relates is generally composed of (a) a “shearing force” generated when the dispersoid passes through a narrow gap at high pressure and high speed, and It is considered that the particles are dispersed into fine particles by a dispersing force such as "cavitation force" generated when the particles are released. As an example of this type of dispersing apparatus, a Gaulin homogenizer is mentioned in the past.In this apparatus, the liquid to be dispersed sent at a high pressure is converted into a high-speed flow through a narrow gap on a cylindrical surface, and the force is applied to the surrounding wall by the force. The particles collide and are emulsified and dispersed by the impact force. Working pressure is generally 10
0~600kg / cm ^2, the flow rate is in the range of a few M～30m / sec have also been devised which a high flow rate portion was devised such increasing the number of collisions in the saw-toothed in order to increase the dispersion efficiency . On the other hand, in recent years, apparatuses capable of dispersing at higher pressure and higher flow rate have been developed, and typical examples thereof include a microfluidizer (Microfluidex International Corporation) and a nanomizer (specialized machine). Industrial Co., Ltd.).

The dispersion apparatus suitable for the present invention includes a microfluidizer M-110S-EH manufactured by Microfluidics International Corporation.
(With G10Z interaction chamber), M-
110Y (with H10Z interaction chamber), M-140K (with G10Z interaction chamber), HC-5000 (L30Z or H23
With 0Z interaction chamber), HC-80
00 (with an E230Z or L30Z interaction chamber) and the like. Using these devices,
After the aqueous dispersion containing at least the organic silver salt is pressurized by a high-pressure pump or the like and sent into the pipe, a desired pressure is applied by passing through a narrow slit provided in the pipe, and thereafter, the inside of the pipe is It is possible to obtain an optimal organic silver salt dispersion for the present invention by causing a rapid pressure drop in the dispersion by, for example, rapidly returning the pressure to the atmospheric pressure.

In the organic silver salt dispersion, it is possible to obtain a desired particle size by adjusting the flow rate, the differential pressure at the time of pressure drop, and the number of treatments. / Sec to 600m / sec, differential pressure at pressure drop
Is preferably in the range of 900~3000kg / cm ^2, the flow rate is 300 meters / sec to 60
More preferably, the pressure difference at the time of 0 m / sec and the pressure drop is in the range of 1500 to 3000 kg / cm ² . The number of times of distributed processing can be selected as needed, and usually 1 to 10 times of processing is selected,
From the viewpoint of productivity, the number of treatments is selected about once to three times.
High temperature of such an aqueous dispersion under high pressure is not preferable from the viewpoint of dispersibility and photographic properties, and at a high temperature such as exceeding 90 ° C., the particle size tends to increase,
Fog tends to be high. Therefore, in the present invention, the step before the conversion to the high pressure and high flow rate, the step after the pressure is reduced, or both of these steps include a cooling step, and the temperature of such water dispersion is reduced by the cooling step. ~ 90
C. It is preferably maintained in the range of 5 ° C., more preferably in the range of 5 to 80 ° C., particularly preferably in the range of 5 to 65 ° C. In particular, it is effective to provide the above cooling step at the time of high-pressure dispersion in the range of 1500 to 3000 kg / cm ² .
As the cooler, a double tube, a double tube using a static mixer, a multi-tube heat exchanger, a coiled tube heat exchanger, or the like can be appropriately selected according to the required heat exchange amount. Further, in order to increase the efficiency of heat exchange, it is sufficient to select a suitable one such as a pipe thickness, a wall thickness and a material in consideration of a working pressure. As the refrigerant used for the cooler, use 20 ° C well water, 5-10 ° C cold water treated with a refrigerator, and, if necessary, -30 ° C ethylene glycol / water refrigerant, etc., based on the heat exchange amount. You can also.

In the dispersion operation, it is preferable to disperse the organic silver salt in the presence of an aqueous solvent-soluble dispersant (dispersion aid). Examples of the dispersing agent include polyacrylic acid, a copolymer of acrylic acid, a maleic acid copolymer, a maleic acid monoester copolymer, a synthetic anionic polymer such as an acrylomethylpropanesulfonic acid copolymer, and carboxymethyl. Starch, semi-synthetic anionic polymer such as carboxymethyl cellulose, alginic acid, anionic polymer such as pectic acid, the compound described in JP-A-7-350753,
Alternatively, known anionic, nonionic, cationic surfactants and other known polymers such as polyvinyl alcohol, polyvinylpyrrolidone, carboxymethylcellulose, hydroxypropylcellulose, and hydroxypropylmethylcellulose, or naturally occurring polymer compounds such as gelatin Can be appropriately selected and used, but polyvinyl alcohols and water-soluble cellulose derivatives are particularly preferred. Dispersing aid is mixed with organic silver salt powder or wet cake organic silver salt before dispersion,
It is a general method to send the slurry as a slurry to a dispersing machine, but it may be subjected to a heat treatment or a treatment with a solvent in a state where the slurry is mixed with an organic silver salt in advance to obtain an organic silver salt powder or a wet cake. The pH may be controlled by a suitable pH adjuster before, during or after dispersion.

In addition to the mechanical dispersion, the particles may be coarsely dispersed in a solvent by controlling the pH, and then finely divided by changing the pH in the presence of a dispersing aid. At this time, an organic solvent may be used as a solvent used for the coarse dispersion, and the organic solvent is usually removed after the completion of the fine particle formation. The prepared dispersion is stored with stirring for the purpose of suppressing sedimentation of fine particles during storage, or stored in a highly viscous state by a hydrophilic colloid (for example, in a jelly state using gelatin). You can also. Further, a preservative can be added for the purpose of preventing the propagation of various bacteria during storage. The organic silver salt in the present invention can be used in a desired amount, show a coating amount per the photosensitive material 1 m ^2, preferably 0.1-5 g / m ² as silver amount, more preferably is 1 to 3 g / m ² .

As the binder for the image forming layer (photosensitive layer, emulsion layer) in the present invention, well-known natural or synthetic resins such as gelatin, polyvinyl acetal, polyvinyl chloride, polyvinyl acetate, cellulose acetate, polyolefin, Any material can be selected from polyester, polystyrene, polyacrylonitrile, polycarbonate and the like. Of course, copolymers and terpolymers are also included. Preferred polymers are polyvinyl butyral, butyl ethyl cellulose, methacrylate copolymer, maleic anhydride copolymer, polystyrene and butadiene-
It is a styrene copolymer. If necessary, two or more of these polymers can be used in combination. Such a polymer is used in an amount sufficient to hold the components therein. That is, it is used in a range effective to function as a binder. The effective range can be appropriately determined by those skilled in the art. As a guide when at least the organic silver salt is retained, the ratio of the binder to the organic silver salt is preferably 15: 1 to 1: 2, particularly preferably 8: 1 to 1: 1.

At least one of the image forming layers in the present invention is preferably an image forming layer containing the polymer latex described below in an amount of 50% by weight or more of the total binder. (Hereinafter, this image forming layer is referred to as "image forming layer in the present invention", and the polymer latex used for the binder is referred to as "polymer latex used in the present invention".)
The polymer latex may be used not only for the image forming layer, but also for the protective layer and the back layer. It is also necessary to use a polymer latex. However, here, "polymer latex"
The term “water-insoluble hydrophobic polymer” means fine particles dispersed in a water-soluble dispersion medium. The dispersion state is such that the polymer is emulsified in a dispersion medium, emulsion-polymerized, micelle-dispersed, or partially dispersed in polymer molecules and molecular chains themselves are molecularly dispersed. Any of them may be used. For the polymer latex used in the present invention, `` synthetic resin emulsion (Taira Okuda, Hiroshi Inagaki, edited by Polymer Publishing Association (1978)),
`` Application of synthetic latex (Takaaki Sugimura, Yasuo Kataoka, Soichi Suzuki, Keiji Kasahara, edited by Polymer Publishing Association (1993)) '', `` Chemistry of synthetic latex (Souichi Muroi, published by Polymer Publishing Association (19)
70)) ”. The average particle size of the dispersed particles is 1
The range is preferably about 50,000 nm, more preferably about 5 to 1,000 nm. There is no particular limitation on the particle size distribution of the dispersed particles,
Those having a wide particle size distribution or those having a monodispersed particle size distribution may be used.

The polymer latex used in the present invention may be a so-called core / shell type latex other than a polymer latex having a normal uniform structure. In this case, it may be preferable to change the glass transition temperature of the core and the shell. The preferred range of the glass transition temperature (Tg) of the polymer of the polymer latex used as a binder in the present invention differs between the protective layer, the back layer and the image forming layer. In the image forming layer, the temperature is preferably 40 ° C. or lower, more preferably -30 to 40 ° C., in order to promote diffusion of the photographically useful material during thermal development. When used for the protective layer or the back layer, a glass transition temperature of 25 to 70 ° C. is preferable for contacting various devices.

The minimum film forming temperature (MFT) of the polymer latex used in the present invention is -30 ° C. to 90 ° C., more preferably 0 ° C.
About 70 ° C. is preferable. A film-forming auxiliary may be added to control the minimum film-forming temperature. The film-forming assistant is also called a plasticizer and is an organic compound (usually an organic solvent) that lowers the minimum film-forming temperature of the polymer latex.
0)) ". Examples of the polymer species used in the polymer latex used in the present invention include acrylic resins, vinyl acetate resins, polyester resins, polyurethane resins, rubber resins, vinyl chloride resins, vinylidene chloride resins, polyolefin resins, and copolymers thereof. is there. The polymer may be a linear polymer, a branched polymer, or a crosslinked polymer.
The polymer may be a so-called homopolymer in which a single monomer is polymerized, or a copolymer in which two or more monomers are polymerized. In the case of a copolymer, it may be a random copolymer or a block copolymer. The polymer has a number average molecular weight of 5000 to 10000000, preferably 1
It is preferably about 0000 to 100,000. If the molecular weight is too small, the mechanical strength of the image forming layer is insufficient, and if it is too large, the film-forming property is poor, which is not preferable.

Specific examples of the polymer latex used as a binder for the image forming layer of the heat-developable image forming material of the present invention include the following. Latex of methyl methacrylate / ethyl acrylate / methacrylic acid copolymer, latex of methyl methacrylate / 2-ethylhexyl acrylate / styrene / acrylic acid copolymer, latex of styrene / butadiene / acrylic acid copolymer, latex of styrene / butadiene / divinylbenzene / methacrylic acid copolymer Latex of methyl methacrylate / vinyl chloride / acrylic acid copolymer, latex of vinylidene chloride / ethyl acrylate / acrylonitrile / methacrylic acid copolymer, and the like. Such polymers are also commercially available,
The following polymers can be used. For example, as an example of an acrylic resin, Sebian A-4635,46583,4601 (all manufactured by Daicel Chemical Industries, Ltd.), Nipol Lx811, 814, 821, 82
Polyester resins such as 0, 857 (all manufactured by Nippon Zeon Co., Ltd.) include FINETEX ES650, 611, 675, 850 (all manufactured by Dainippon Ink and Chemicals, Inc.), WD-size, WMS (all manufactured by Eastman Chemical Co., Ltd.) HYDRAN for polyurethane resin
LACSTAR 7310K, 3307B, 4700 are rubber-based resins such as AP10, 20, 30, 40 (all manufactured by Dainippon Ink and Chemicals, Inc.)
H, 7132C (all manufactured by Dainippon Ink and Chemicals, Inc.), Nipol Lx4
16, 410, 438C, 2507 (all manufactured by Nippon Zeon Co., Ltd.), etc.
Examples of vinyl chloride resins include G351 and G576 (all manufactured by Nippon Zeon Co., Ltd.). Examples of vinylidene chloride resins include L502 and L51.
3 (All made by Asahi Kasei Corporation), Aron D7020, D504, D507
Examples of olefin resins include Chemipearl S120 and SA100 (both manufactured by Mitsui Petrochemical Co., Ltd.). These polymers may be used alone or as a blend of two or more as necessary.

In the image forming layer according to the invention, the polymer latex is preferably used in an amount of 50% by weight or more of the total binder, and more preferably 70% by weight or more. In the image forming layer in the present invention, a hydrophilic polymer such as gelatin, polyvinyl alcohol, methyl cellulose, hydroxypropyl cellulose, carboxymethyl cellulose, or hydroxypropyl methyl cellulose may be added as needed in the range of 50% by weight or less of the whole binder. . The amount of these hydrophilic polymers added is 30% of the total binder of the image forming layer.
% By weight or less, more preferably 15% by weight or less.

The image forming layer in the present invention is preferably prepared by applying an aqueous coating solution and then drying it. However, the `` water-based '' here is 60% by weight of the solvent (dispersion medium) of the coating liquid.
It means that the above is water. As components other than water of the coating solution, water-miscible organic solvents such as methyl alcohol, ethyl alcohol, isopropyl alcohol, methyl cellosolve, ethyl cellosolve, dimethylformamide, and ethyl acetate can be used. Specific examples of the solvent composition include the following in addition to water. Water / methanol = 90/10, water / methanol = 70/30, water / ethanol = 9
0/10, water / isopropanol = 90/10, water / dimethylformamide = 95/5, water / methanol / dimethylformamide = 80/15/5, water / methanol / dimethylformamide = 90/5/5. (However, the numbers represent% by weight.) The total binder amount of the image forming layer in the present invention is 0.2 to 30 g.
/ M ² , more preferably in the range of 1 to 15 g / m ² . A crosslinking agent for crosslinking, a surfactant for improving coating properties, and the like may be added to the image forming layer in the invention.

As the sensitizing dye used in the present invention, any sensitizing dye may be used as long as it can spectrally sensitize the silver halide grains in a desired wavelength region when adsorbed on the silver halide grains. As the sensitizing dye, a cyanine dye, a merocyanine dye, a complex cyanine dye, a complex merocyanine dye, a holopolar cyanine dye, a styryl dye, a hemicyanine dye, an oxonol dye, a hemioxonol dye, and the like can be used. Useful sensitizing dyes for use in the present invention include, for example, RESEARCH DISCLOSURE Item 17
Item 643IV-A (p.23, December 1978), Item 1831X (August 1979)
p.437) or in the literature cited. In particular, a sensitizing dye having a spectral sensitivity suitable for the spectral characteristics of the light source of various laser imagers, scanners, imagesetters and plate making cameras can be advantageously selected.

As an example of spectral sensitization to red light, He-Ne
For a so-called red light source such as a laser, a red semiconductor laser or an LED, a compound of I-1 to I-38 described in JP-A-54-18726, and a compound of I-1 described in JP-A-6-75322. I-3
5 and the compounds I-1 to I- described in JP-A-7-287338.
34 compounds, dyes 1 to 20 described in JP-B-55-39818,
The compounds I-1 to I-37 described in JP-A-62-284343 and the compounds I-1 to I-34 described in JP-A-7-287338 are advantageously selected. For a semiconductor laser light source in the wavelength range of 750 to 1400 nm, cyanine, merocyanine,
Various known dyes, including styryl, hemicyanine, oxonol, hemioxonol and xanthene dyes, can be spectrally sensitized advantageously. Useful cyanine dyes are, for example, cyanine dyes having a basic nucleus, such as a thiazoline nucleus, an oxazoline nucleus, a pyrroline nucleus, a pyridine nucleus, an oxazole nucleus, a thiazole nucleus, a selenazole nucleus and an imidazole nucleus. Preferred useful merocyanine dyes include, in addition to the above basic nuclei, a thiohydantoin nucleus, a rhodanine nucleus, an oxazolidinedione nucleus, a thiazolinedione nucleus, a barbituric acid nucleus,
Also includes acidic nuclei such as thiazolinone nuclei, malononitrile nuclei and pyrazolone nuclei. Among the above-mentioned cyanine and merocyanine dyes, those having an imino group or a carboxyl group are particularly effective. For example, U.S. Pat.
9, 3,719,495, 3,877,943, UK Patent 1,466,2
No. 01, No. 1,469,117, No. 1,422,057, Tokuhei 3-10391
No. 6-52387, JP-A-5-341432, 6-94781,
It may be appropriately selected from known dyes as described in JP-A-6-301141.

Particularly preferred as the structure of the dye used in the present invention is a cyanine dye having a thioether bond-containing substituent (for example, see JP-A-62-58239 and JP-A-3-13863).
No.8, No.3-138642, No.4-255840, No.5-72659, No.5-
No. 72661, No. 6-222491, No. 2-230506, No. 6-258757
No., 6-317868, 6-324425, Tokuyohei 7-500926,
Dyes described in U.S. Pat.
No. 141, dyes described in U.S. Patent No.
No. 52-80829, No. 54-61517, No. 59-214846, No. 60-67
No. 50, 63-159841, JP-A-6-35109, 6-59381
No., 77-146537, 77-146537, Tokuyohei 55-50111,
Dyes described in British Patent 1,467,638 and US Patent 5,281,515). Further, as a dye forming a J-band, U.S. Pat.No. 5,510,236, the dye described in Example 5 of 3,871,887, JP-A-2-96131, JP-A-59-48753 are disclosed, and are preferably used in the present invention. Can be used.

These sensitizing dyes may be used alone.
Two or more kinds may be used in combination. Combinations of sensitizing dyes are often used, especially for supersensitization. In addition to the sensitizing dye, the emulsion may contain a dye which does not itself have a spectral sensitizing effect or a substance which does not substantially absorb visible light and exhibits supersensitization. Useful sensitizing dyes, combinations of dyes exhibiting supersensitization and substances exhibiting supersensitization are
Research Disclosure Volume 176, 17643 (Issued December 1978) No. 23
Section IV on page IV, or JP-B-49-25500, 43-43933,
These are described in JP-A-59-19032 and JP-A-59-192242. In order to add a sensitizing dye to a silver halide emulsion,
They may be dispersed directly in the emulsion, or
Methanol, ethanol, propanol, acetone, methylcellosolve, 2,2,3,3-tetrafluoropropanol, 2,2,2-trifluoroethanol, 3-methoxy-1-propanol, 3-methoxy-1-butanol, 1-methoxy-2-
A solvent such as propanol and N, N-dimethylformamide alone or in a mixed solvent may be added to the emulsion.

Further, as disclosed in US Pat. No. 3,469,987, a dye is dissolved in a volatile organic solvent, this solution is dispersed in water or a hydrophilic colloid, and this dispersion is dispersed in an emulsion. To Japanese Patent Publication No. 44-23389,
As disclosed in JP-A-44-27555 and JP-A-57-22091, the dye is dissolved in an acid and this solution is added to the emulsion, or an acid or base is added to the emulsion as an aqueous solution in the presence of an acid or base. A method of adding an aqueous solution or a colloidal dispersion in the presence of a surfactant to an emulsion, as disclosed in U.S. Patent Nos. 3,822,135 and 4,006,025, JP-A-53-102733. JP-A-51-746, a method in which a dye is directly dispersed in a hydrophilic colloid and the dispersion is added to an emulsion as disclosed in JP-A-58-105141.
As disclosed in Japanese Patent No. 24, a method in which a dye is dissolved using a compound that causes a red shift, and this solution is added to an emulsion can also be used. Also, ultrasonic waves can be used for dissolution.

The sensitizing dye may be added to the silver halide emulsion at any time during the preparation of the emulsion which has been found to be useful. US Patent
2,735,766, 3,628,960, 4,183,756, 4,22
No. 5,666, JP-A-58-184142, JP-A-60-196749, etc., as disclosed in the silver halide grain forming step or / and the time before the desalting, during the desalting step and / or during the desalting step. Alternatively, from the time after desalination to before the start of chemical ripening,
As disclosed in the specification such as -113920, the timing immediately before or during chemical ripening, at any time after the chemical ripening and before coating, the emulsion is added at any time during the process. Is also good. U.S. Pat. No. 4,225,666
As disclosed in the specification such as JP-A-58-7629, the same compound may be used alone or in combination with a compound having a different structure, for example, during the particle forming step and during the chemical ripening step or when the chemical ripening is completed. May be added separately, such as before or after chemical ripening or during the process and after completion, or may be added by changing the type of compound and compound combination to be added and divided. Good. The amount of the sensitizing dye used may be a desired amount in accordance with the performance such as sensitivity and fog, but is preferably 10 ^-6 to 1 mol, more preferably 10 ^-4 to 10 ^-1 per mol of silver halide in the photosensitive layer. Mole is more preferred.

The heat-developable image-forming material of the present invention may contain a mercapto compound, a disulfide or the like for controlling or developing by controlling the development, for improving the spectral sensitization efficiency, or for improving the storage stability before and after the development. Compounds and thione compounds can be contained. When a mercapto compound is used in the present invention, it may have any structure, but is preferably a compound represented by Ar-SM 2 ^O or Ar-SS-Ar. Wherein, M ^O is a hydrogen atom or an alkali metal atom, Ar is an aromatic ring or fused aromatic ring group having one or more nitrogen, sulfur, oxygen, selenium or tellurium atom. Preferably, the heteroaromatic rings in these groups are benzimidazole, naphthimidazole, benzothiazole,
Naphthothiazole, benzoxazole, naphthoxazole, benzoselenazole, benzotellurazole, imidazole, oxazole, pyrazole, triazole, thiadiazole, tetrazole, triazine, pyrimidine, pyridazine, pyrazine, pyridine, purine, quinoline or quinazolinone. This heteroaromatic ring is
For example, halogens (e.g., Br and Cl), hydroxy,
Amino, carboxy, alkyl (e.g., those having one or more carbon atoms, preferably 1-4 carbon atoms), alkoxy (e.g., one or more carbon atoms, preferably 1-4 carbon atoms) Having a substituent) and aryl (which may have a substituent). As mercapto-substituted heteroaromatic compounds, 2-mercaptobenzimidazole, 2-mercaptobenzoxazole, 2-mercaptobenzothiazole, 2-mercapto-5-methylbenzimidazole, 6-ethoxy-2-mercaptobenzothiazole,
2,2'-dithiobis-benzothiazole, 3-mercapto-1,
2,4-triazole, 4,5-diphenyl-2-imidazolethiol, 2-mercaptoimidazole, 1-ethyl-2-mercaptobenzimidazole, 2-mercaptoquinoline, 8-
Mercaptopurine, 2-mercapto-4 (3H) -quinazolinone, 7-trifluoromethyl-4-quinolinethiol, 2,3,
5,6-tetrachloro-4-pyridinethiol, 4-amino-6-hydroxy-2-mercaptopyrimidine monohydrate, 2-
Amino-5-mercapto-1,3,4-thiadiazole, 3-amino
-5-Mercapto-1,2,4-triazole, 4-hydrokilos-2-
Mercaptopyrimidine, 2-mercaptopyrimidine, 4,6-
Diamino-2-mercaptopyrimidine, 2-mercapto-4-methylpyrimidine hydrochloride, 3-mercapto-5-phenyl-1,2,4-triazole, 1-phenyl-5-mercaptotetrazole, 3- (5-mercaptotetrazole ) -Sodium benzenesulfonate, N-methyl-N '-[3- (5-mercaptotetrazolyl) phenyl] urea, 2-mercapto-4-phenyloxazole, and the like, but the invention is not limited thereto. .

The addition amount of these mercapto compounds is 0.0001 to 1 per mol of silver in the emulsion layer (image forming layer).
A molar range is preferred, more preferably an amount of 0.001 to 0.3 mole per mole of silver. The image forming layer (photosensitive layer) in the heat-developable image forming material of the present invention may contain a polyhydric alcohol (for example, glycerin and diol of the type described in U.S. Pat. No. 2,960,404) as a plasticizer and a lubricant. Nos. 2,588,765 and 3,121,060
No. 955,061.
And the like.

The heat-developable image-forming material of the present invention may have a surface protective layer for the purpose of preventing adhesion of the image-forming layer. Although any polymer may be used as the binder for the surface protective layer, the polymer having a carboxylic acid residue may be 100 mg /
preferably contains m ² or more 5 g / m ² or less. Examples of the polymer having a carboxyl residue include natural polymers (gelatin, alginic acid, etc.), modified natural polymers (carboxymethylcellulose, phthalated gelatin, etc.), and synthetic polymers (polymethacrylate, polyacrylate, polyalkylmethacrylate / acrylate). Copolymer, polystyrene / polymethacrylate copolymer, etc.). The carboxy residue content of such a polymer is preferably from 10 mmol to 1.4 mol per 100 g of the polymer. Further, the carboxylic acid residue may form a salt with an alkali metal ion, an alkaline earth metal ion, an organic cation, or the like.

As the surface protective layer, any anti-adhesion material may be used. Examples of anti-adhesion materials include wax, silica particles, styrene-containing elastomeric block copolymers (e.g., styrene-butadiene-styrene, styrene-isoprene-styrene), cellulose acetate, cellulose acetate butyrate, cellulose propionate and the like. And mixtures. Further, a crosslinking agent for crosslinking, a surfactant for improving coating properties, and the like may be added to the surface protective layer. The image forming layer or the protective layer of the image forming layer in the heat-developable image forming material of the present invention includes U.S. Pat.
Light absorbing materials and filter dyes as described in 527,583 and 2,956,879 can be used. Further, a dye can be mordant as described in, for example, US Pat. No. 3,282,699. As the amount of the filter dye used, the absorbance at the exposure wavelength is preferably 0.1 to 3,
0.2 to 1.5 is particularly preferred.

Various dyes and pigments can be used in the photosensitive layer of the heat-developable image forming material of the present invention from the viewpoint of improving color tone and preventing irradiation. Dyes and pigments used in the photosensitive layer may be any, for example, pigments and dyes described in the color index, specifically, pyrazoloazole dye, anthraquinone dye, azo dye,
Organic pigments such as azomethine dyes, oxonol dyes, carbocyanine dyes, styryl dyes, triphenylmethane dyes, indoaniline dyes, indophenol dyes, and phthalocyanines, and inorganic pigments. Preferred dyes used in the present invention include anthraquinone dyes (e.g., compounds 1 to 9 described in JP-A-5-341441, compounds 3-6 to 18 and 3-23 to 38 described in JP-A-5-165147), azomethine Dye (compound 17 described in JP-A-5-341441)
To 47 etc.), indoaniline dyes (e.g. JP-A-5-289227)
Nos. 11 to 19 and compounds described in JP-A-5-341441
47, compounds 2-10 to 11 described in JP-A-5-165147, and azo dyes (compounds 10 to 16 described in JP-A-5-341441). As a method for adding these dyes, any method such as a solution, an emulsion, a solid fine particle dispersion, and a state in which the dye is mordanted with a polymer mordant may be used. The amount of these compounds used is determined by the desired absorption, but generally 1 m
It is preferable to use 1 μg or more and 1 g or less per ² .

The heat-developable image-forming material of the present invention has at least one light-sensitive layer (image-forming layer) containing a silver halide emulsion on one side of a support and has a back layer on the other side. It is preferably a so-called single-sided photosensitive material. In the present invention, the back layer has a maximum absorption of about
It is preferably from 0.3 to 2.0. The desired range is 75
When it is 0 to 1400 nm, the optical density at 750 to 360 nm is preferably 0.005 or more and less than 0.5, and more preferably an antihalation layer having an optical density of 0.001 or more and less than 0.3. Desired range is 750n
m or less, the maximum absorption in the desired range before image formation is 0.3 or more and 2.0 or less, and 360 to 7 after image formation.
It is preferable that the antihalation layer has an optical density at 50 nm of 0.005 or more and less than 0.3. There is no particular limitation on the method of reducing the optical density after image formation to the above range, for example, a method of reducing the density by dyeing by heating to reduce the density by heating as described in Belgian Patent No. 733,706,
Japanese Patent Application Laid-Open No. Sho 54-17833 discloses a method of reducing the density by decoloring by light irradiation.

When antihalation dyes are used in the present invention, such dyes have the desired absorption in the desired range,
Any compound may be used as long as it has a sufficiently low absorption in the visible region after the treatment and a preferable absorbance spectrum of the back layer is obtained. For example, the following are disclosed, but the present invention is not limited thereto. As a single dye, JP-A-59-56458, JP-A-2-216140,
No. 7-13295, No. 7-11432, U.S. Pat.No.5,380,635, JP-A-2-688539, page 13, lower left column, line 1 to line 14,
The lower left column of the page, line 9, from the lower left column of page 14 of JP-A-3-24539
There are compounds described in the lower right column of page 16, and as dyes which can be decolorized by treatment, JP-A Nos. 52-139136, 53-132334, 56-50148.
No. 0, No. 57-16060, No. 57-68831, No. 57-101835, No.
No. 59-182436, JP-A-7-36145, 7-199409
No. 48-33692, No. 50-16648, Japanese Patent Publication No. 2-41734, U.S. Pat.Nos. 4,088,497, 4,283,487, 4,548,896, 5,1
There is 87,049.

In the present invention, suitable binders for the back layer are transparent or translucent, generally colorless, and natural polymer synthetic resins, polymers and copolymers, and other film-forming media such as: gelatin, gum arabic, poly (vinyl) (Alcohol), hydroxyethyl cellulose, cellulose acetate, cellulose acetate butyrate, poly (vinyl pyrrolidone), casein, starch, poly (acrylic acid), poly (methyl methacrylic acid), poly (vinyl chloride), poly (methacrylic acid), copoly (Styrene-maleic anhydride), copoly (styrene-acrylonitrile), copoly (styrene-butadiene), poly (vinylacetal) s (e.g., poly (vinylformal) and poly (vinylformal)).
(Vinyl butyral)), poly (ester) s, poly (urethanes), phenoxy resin, poly (vinylidene chloride), poly (vinylidene chloride)
(Epoxides), poly (carbonates), poly (vinyl acetate), cellulose esters, and poly (amides). The binder may be coated from water or an organic solvent or emulsion.

When the heat-developable image-forming material of the present invention is a single-sided photosensitive material, it may be added to a surface protective layer of a photosensitive emulsion layer (image forming layer) and / or a back layer or a surface protective layer of a back layer for improving transportability. A matting agent may be added. The matting agent is generally fine particles of an organic or inorganic compound insoluble in water. Any matting agent can be used, for example, U.S. Patent Nos. 1,939,213, 2,701,245, and 2,322,03
No. 7, 3,262,782, 3,539,344, 3,767,448, etc.
2,192,241, 3,257,206, 3,370,951, 3,52
Inorganic matting agents well-known in the art, such as inorganic matting agents described in the respective specifications such as 3,022 and 3,769,020 can be used. For example, specifically, examples of organic compounds that can be used as a matting agent include polymethyl acrylate, polymethyl methacrylate, polyacrylonitrile, acrylonitrile-α-methylstyrene copolymer, and polystyrene as examples of a water-dispersible vinyl polymer. , Styrene-divinylbenzene copolymer, polyvinyl acetate, polyethylene carbonate, polytetrafluoroethylene, etc., examples of cellulose derivatives such as methylcellulose,
Examples of starch derivatives such as cellulose acetate, cellulose acetate propionate, carboxy starch, carboxynitrophenyl starch, urea-formaldehyde-
Gelatin hardened with a known hardener, such as a starch reactant, and hardened gelatin formed into microcapsules by coacervate hardening can be preferably used. Examples of the inorganic compound include silicon dioxide, titanium dioxide, magnesium dioxide, aluminum oxide, barium sulfate, calcium carbonate, silver chloride desensitized by a known method, silver bromide, glass, and diatomaceous earth. The above matting agents can be used by mixing different types of substances as necessary. The size and shape of the matting agent are not particularly limited, and those having an arbitrary particle size can be used. In practicing the present invention, it is preferable to use one having a particle size of 0.1 μm to 30 μm. Further, the particle size distribution of the matting agent may be narrow or wide. On the other hand, since the matting agent greatly affects the haze and surface gloss of the light-sensitive material, the particle size, shape, and particle size distribution can be changed as necessary during the preparation of the matting agent or by mixing a plurality of matting agents. preferable.

In the present invention, it is a preferred embodiment to add a matting agent to the backing layer. The matting degree of the backing layer is preferably a Beck smoothness of 1200 seconds or less and 10 seconds or more, more preferably 700 seconds or less and 50 seconds or more. It is. In the present invention, the matting agent is preferably contained in the outermost surface layer of the image forming material or a layer functioning as the outermost surface layer, or a layer close to the outer surface, and is contained in a layer acting as a so-called protective layer. Preferably. The degree of matting of the emulsion surface protective layer may be any value as long as stardust failure does not occur, but the Beck smoothness is preferably 500 seconds or more and 10,000 seconds or less, particularly preferably 500 seconds or more and 2,000 seconds or less.

In the heat-developable image-forming material of the present invention, the heat-developable photographic emulsion forms one or more layers on a support. One layer must contain additional optional materials such as organic silver salts, silver halides, developers and binders, and toning agents, coating aids and other auxiliaries. The two-layer construction is such that the first emulsion layer (usually the layer adjacent to the support) contains an organic silver salt and silver halide and the second layer or both layers do not contain some other components. No. However, a two-layer construction comprising a single emulsion layer containing all components and a protective topcoat is also contemplated. The construction of a multicolor light-sensitive photothermographic material may include a combination of these two layers for each color, and US Pat.
All components may be contained in a single layer as described in 4,708,928. In the case of a multi-dye, multi-color photosensitive heat-developable photographic material, each emulsion layer is generally comprised of U.S. Pat.
As described in No. 1, by using a functional or non-functional barrier layer between each emulsion layer (photosensitive layer), it is kept distinct from each other. U.S. Patent 4,
Backside resistive heating layers such as those shown in US Pat. Nos. 460,681 and 4,374,921 can also be used in the photothermographic image systems.

In the heat-developable image forming material of the present invention, a hardener may be used for each of the image forming layer (photosensitive layer), the protective layer, the back layer and the like. Examples of the hardener include U.S. Pat.No.4,281,060, polyisocyanates described in JP-A-6-208193, epoxy compounds described in U.S. Pat.No.4,791,042, JP-A-62-89048. For example, vinyl sulfone compounds described in US Pat. A surfactant may be used in the heat-developable image forming material of the present invention for the purpose of improving coating properties and charging. As the surfactant, any surfactant such as nonionic, anionic, cationic, and fluorine can be used as appropriate.
Specifically, JP-A-62-170950, a fluoropolymer surfactant described in U.S. Pat.
No. 945, fluorine-based surfactants described in JP-A-63-188135, etc., polysiloxane-based surfactants described in U.S. Pat. No. 3,885,965, polyalkylene oxides and anions described in JP-A-6-301140 and the like Surfactants and the like.

The photographic emulsion for heat development used in the present invention can be generally coated on various supports. Typical supports include polyester films, primed polyester films, poly (ethylene terephthalate) films, polyethylene naphthalate films, cellulose nitrate films, cellulose ester films, poly (vinyl acetal) films, polycarbonate films and related or resinous Materials, as well as glass,
Including paper, metal, etc. Flexible substrates, particularly coated with baryta and / or partially acetylated α-olefin polymers, especially polymers of C 2-10 α-olefins such as polyethylene, polypropylene, ethylene-butene copolymers A paper support is typically used. Such a support may be transparent or opaque, but is preferably transparent. Among them, biaxially stretched polyethylene terephthalate (PET) of about 75 to 200 μm is particularly preferred.

On the other hand, when a plastic film is passed through a heat developing machine at a temperature of 80 ° C. or more, the dimensions of the film generally expand and contract. If the processed material is used for printing plate making,
This expansion and contraction is a serious problem when performing precision multicolor printing.
Therefore, in the present invention, it is preferable to use a film having a small dimensional change, which is designed to reduce internal strain remaining in the film at the time of biaxial stretching and eliminate thermal shrinkage distortion generated during thermal development. For example, polyethylene terephthalate, which is heat-treated at 100 to 210 ° C. before coating the photographic emulsion for thermal development, is preferably used. Those having a high glass transition temperature are also preferable, and polyether ethyl ketone, polystyrene, polysulfone, polyethersulfone, polyarylate, polycarbonate and the like can be used. The heat-developable image forming material of the present invention is, for antistatic,
For example, soluble salts (eg, chlorides, nitrates, etc.), deposited metal layers, ionic polymers as described in US Pat. Nos. 2,861,056 and 3,206,312 or US Pat.
Insoluble inorganic salts as described in 8,451, JP-A-60-252349
And a layer containing fine particles of tin oxide described in JP-A-57-104931.

A method for obtaining a color image using the heat-developable image forming material of the present invention is described in JP-A-7-13295, page 10, left column 43.
There is a method described from line 11 to line 40 in the left column. In addition, as a stabilizer of color dye image, British Patent No. 1,326,889,
U.S. Pat.Nos. 3,432,300, 3,698,909, 3,574,
No. 627, No. 3,573,050, No. 3,764,337 and No.
No. 4,042,394. The photothermographic emulsion used in the present invention may be a dip coating, an air knife coating, a flow coating, or US Pat.
It can be coated by a variety of coating operations, including extrusion coating using a hopper of the type described in Ref. If desired, two or more layers can be coated simultaneously by the methods described in US Pat. No. 2,761,791 and British Patent No. 837,095.

Additional layers in the heat-developable image-forming material of the present invention, for example, a dye-receiving layer for receiving a transfer dye image,
If reflective printing is desired, it can include an opacifying layer, a protective topcoat layer, a primer layer known in the photothermographic art, and the like. It is preferable that the heat-developable image forming material of the present invention can form an image with only one image forming material, and it is preferable that a functional layer such as an image receiving layer necessary for image formation does not become another image forming material.

The heat-developable image-forming material of the present invention may be developed by any method, but is usually developed by elevating the temperature of a photosensitive material exposed imagewise. As a preferred embodiment of the heat developing machine to be used, as a type in which the heat-developable image forming material is brought into contact with a heat source such as a heat roller or a heat drum, Japanese Patent Publication No. 5-56499, Patent Publication No. 684453,
-292695, JP-A-9-297385 and International Publication WO95 / 30
There is a heat developing machine described in Japanese Patent Application Laid-Open No. 934 and a non-contact type heat developing machine described in JP-A-7-13294, WO 97/28489, WO 97/28488 and 97/28487. A particularly preferred embodiment is a non-contact type thermal developing machine. The preferred development temperature is 80 to 250 ° C., more preferably 1 to 250 ° C.
00-140 ° C. The development time is preferably from 1 to 180 seconds, more preferably from 10 to 90 seconds. As a method for preventing processing unevenness due to the above-mentioned dimensional change during the heat development of the heat-developable image forming material of the present invention, 80 ° C. or more and less than 115 ° C. (preferably 113 ° C. or less)
(5 ° C. or less) and heating for 5 seconds or more to prevent image formation, and then heat developing at 110 ° C. or more (preferably 130 ° C. or less) to form an image (a so-called multi-step heating method) is effective. .

The heat-developable image forming material of the present invention may be exposed by any method, but a laser beam is preferred as an exposure light source. As the laser light used in the present invention, a gas laser, a YAG laser, a dye laser, a semiconductor laser and the like are preferable. Further, a semiconductor laser and a second harmonic generation element can be used. The heat-developable image-forming material of the present invention has a low haze at the time of exposure and tends to cause interference fringes. Examples of this interference fringe prevention technology include a technology disclosed in Japanese Patent Application Laid-Open No. HEI 5-113548 for obliquely entering a laser beam into a photosensitive material, and a technology disclosed in International Publication WO95 / 317.
A method using a multi-mode laser disclosed in, for example, Japanese Patent No. 54 is known, and it is preferable to use these techniques. To expose the heat-developable image forming material of the present invention
SPIE vol.169 Laser Printing 116-128 pages (1979), JP-A-4-51043, exposure so that the laser light is overlapped as disclosed in International Publication WO95 / 31754, etc., so that the scanning lines are not visible Is preferable.

FIG. 1 shows an example of the configuration of a heat developing machine used for the heat development of the heat-developable image forming material of the present invention. FIG. 1 is a side view of the heat developing machine. A transfer endless belt 4 suspended by a plurality of feed rollers 3 is pressed against the peripheral surface of a cylindrical heat drum 2 containing a halogen lamp 1 as a heat source of a heating means therein, and the endless belt 4 and the heat drum 2 is conveyed with the heat-developable image forming material 5 interposed therebetween. While being transported, the heat-developable image forming material 5 is heated to a development temperature, and heat development is performed. In this case, the orientation of the lamp is optimized, and the temperature control in the width direction is performed accurately. A guide plate 7 for correcting the heat-developable material 5 released from the curvature of the peripheral surface of the heat drum 2 into a flat shape near an outlet 6 from which the heat-developable image-forming material 5 is sent out between the heat drum 2 and the endless belt 4.
Is provided. In the vicinity of the guide plate 7, the ambient temperature is adjusted so that the temperature of the heat-developable image forming material 5 does not become lower than a predetermined temperature.

A pair of feed rollers 8 for feeding the heat-developable image-forming material 5 is provided downstream of the outlet 6, and the heat-developable image-forming material 5 is arranged downstream thereof adjacent to the pair of feed rollers 8. A pair of flat guide plates 9 for guiding while being maintained is provided, and further downstream thereof, another pair of feed rollers 10 is provided adjacent to the flat guide plates 9. The flat guide plate 9 has such a length that the heat-developable image-forming material 5 is cooled while the heat-developable image-forming material 5 is conveyed therebetween. That is, during this time, the heat-developable image forming material 5 is cooled until the temperature thereof becomes 30 ° C. or less.
As this cooling means, a cooling fan 11 is provided. As described above, the description has been given according to the illustrated example.
For example, the thermal developing machine used in the present invention, such as that described in JP-A-7-13294, may have various configurations. In the case of the multi-stage heating method preferably used in the present invention, two or more heat sources having different heating temperatures may be provided in the above-described apparatus, and heating may be performed continuously at different temperatures.

[0121]

The present invention will be described more specifically with reference to the following examples. The materials, amounts, proportions,
The operation and the like can be appropriately changed without departing from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the following specific examples. (Example 1) The compounds used in Example 1 are shown below.

[0122]

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1. Preparation of Organic Acid Silver Emulsion 933 g of behenic acid was added to 12 liters of water, and while keeping at 90 ° C., a solution prepared by dissolving 48 g of sodium hydroxide and 63 g of sodium carbonate in 1.5 liters of water was added. After stirring for 30 minutes
The temperature was adjusted to 50 ° C., 1.1 L of a 1% aqueous solution of N-bromosuccinimide was added, and 2.3 L of a 17% aqueous solution of silver nitrate were gradually added with stirring. Furthermore, the liquid temperature was set to 35 ° C., 1.5 liters of a 2% aqueous solution of potassium bromide was added over 2 minutes with stirring, and the mixture was stirred for 30 minutes, and 2.4 liters of a 1% aqueous solution of N-bromosuccinimide was added. While stirring this aqueous mixture, 3300 g of a 1.2 wt% polyvinyl acetate butyl acetate solution
Was added and left standing for 10 minutes to separate into two layers, the aqueous layer was removed, and the remaining gel was washed twice with water. The gel mixture of silver behenate and silver bromide thus obtained was dispersed in 1800 g of a 2.6% 2-butanone solution of polyvinyl butyral (Denka Butyral # 3000-K, manufactured by Denki Kagaku Kogyo Co., Ltd.), and further dispersed in polyvinyl butyral ( Japan Monsanto
Butvar B-76 manufactured by Co., Ltd.) 600 g, isopropyl alcohol 3
The resulting dispersion was dispersed together with 00 g to obtain an organic acid silver emulsion (acicular particles having an average minor axis of 0.05 μm, an average major axis of 1.2 μm, and a variation coefficient of 25%).

[0124] 2. Preparation of Emulsion Layer Coating Solution Various chemicals were added to the above-obtained organic acid silver emulsion in the following amounts per mole of silver. At 25 ° C, 520m of sensitizing dye A
g, compound (C-1) 1.70 g, 4-chlorobenzophenone-2-carboxylic acid (C-2) 21.5 g, calcium bromide dihydrate 0.
90 g, 2-butanone 580 g and dimethylformamide 220 g were added with stirring and left for 3 hours. Then, 1,1-bis (2
-Hydroxy-3,5-dimethylphenyl) -3,5,5-trimethylhexane (C-3) 160 g, Compound B-42 as contrasting agent
2.1 g, tribromomethylphenylsulfone 13.7 g, dye (C-4) 1.11 g, sumidur N3500 (Sumitomo Bayer Urethane Co., Ltd. polyisocyanate) 6.45 g, Megafax F-176
P (fluorinated surfactant manufactured by Dainippon Ink and Chemicals, Inc.) 0.60 g, 2-butanone 590 g, methyl isobutyl ketone 1
0 g was added with stirring.

[0125] 3. Preparation of Coating Solution for Emulsion Surface Protective Layer CAB171-15S (cellulose acetate butyrate manufactured by Eastman Chemical Co., Ltd.) 65 g, phthalazinone (C-5) 6.3 g, tetrachlorophthalic acid (C-6) 1.91 g, general formula (I) ), A polymer derived from the compound of general formula (II), or a comparative compound, as shown in Table 3, 0.67 g of tetrachlorophthalic anhydride (C-7), 0.36 g of Megafax F-176P, Sildex H31 (Torkai Chemical's spherical silica average size 3μm) 2
g, was dissolved in 1050 g of 2-butanone and 50 g of dimethylformamide.

[0126] 4. Preparation of a support having a back surface 6 g of polyvinyl butyral (Denka Butyral # 4000-2 manufactured by Denki Kagaku Kogyo KK), 0.2 g of Sildex H121 (average size of spherical silica 12 μm manufactured by Dokai Chemical Co., Ltd.), 0.2 g of Sildex H
0.2 g of 51 (Square silica average particle size 5μm, Dokai Chemical)
It was added to 0.1 g of Megafax F-176P and 64 g of 2-propanol with stirring to dissolve and mix. In addition, 420m
g of Dye A in 10 g of methanol and 20 g of acetone and a solution of 0.8 g of 3-isocyanatomethyl-3,5,5-trimethylhexyl isocyanate in 6 g of ethyl acetate were added to prepare a coating solution. A back surface coating solution was applied on a polyethylene terephthalate film having a moisture-proof undercoat containing vinylidene chloride on both sides so as to have an optical density of 0.7 at 780 nm. After silver emulsion layer coating liquid prepared support on as described above was coated to a 1.6 g / m ^2, as the emulsion surface protective layer coating solution onto the emulsion surface a dry thickness of 2.3μm Applied.

[0127] 5. Evaluation of photographic performance Exposure to xenon flash light with an emission time of 10 ^-4 sec through a step wedge through an interference filter with a peak at 780 nm, processing at 117 ° C for 20 seconds (development), and evaluation of the resulting image Was performed. The result of the measurement is Dma
The evaluation was made based on x, fog (Dmin), and sensitivity (S1.5, the reciprocal of the ratio of the exposure amount giving a density 1.5 higher than Dmin). The sensitivity was shown as a relative value with the sensitivity of Sample No. 104 in Table 3 being 100.
The gradient of the straight line connecting the points of density 0.3 and 3.0 in the characteristic curve
As shown. Further, after the unexposed coated sample was sealed and stored at 50 ° C. for 3 days, it was similarly exposed and evaluated. Table 3 shows the results.

[0128]

[Table 3]

6. The results Comparative Sample by storing for 3 days at 50 ° C.,
It can be seen that the sensitivity is significantly reduced and the maximum density is also low. On the other hand, it can be seen that all of the samples of the present invention have a small change in sensitivity due to storage, and suppress an increase in fog.

Example 2 The compounds used in Example 2 are shown below.

[0131]

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[0132] 1. Preparation of silver halide emulsion A In 700 ml of water, 11 g of phthalated gelatin and 30 m of potassium bromide
g, dissolving 10 mg of sodium benzenethiosulfonate, adjusting the pH to 5.0 at a temperature of 55 ° C., and keeping an aqueous solution containing 18.6 g of silver nitrate and an aqueous solution containing potassium bromide at 1 mol / liter at pAg 7.7. It was added over 6 minutes and 30 seconds by the control double jet method. Then, 476 ml of an aqueous solution containing 55.5 g of silver nitrate and a halogen salt aqueous solution containing 1 mol / l of potassium bromide were added by a control double jet method over 28 minutes and 30 seconds while keeping the pAg at 7.7. afterwards
The pH was lowered to cause coagulation sedimentation and desalting treatment.
17g, deionized gelatin (calcium content 20ppm
23.7 g) were added to adjust the pH to 5.9 and pAg8.0. The obtained particles have an average particle size of 0.11 μm and a projected area variation coefficient of 8
%, (100) face ratio of 93%. The silver halide grains thus obtained were heated to 60 ° C., and 76 μmol of sodium benzenethiosulfonate was added per 1 mol of silver.
One minute later, 154 μmol of sodium thiosulfate was added, and the mixture was aged for 100 minutes. After that, keep the temperature at 40 ° C,
6.4 × 10 ^-4 moles of sensitizing dye B and 6.4 × 10 ^-3 moles of compound B were added with stirring, and after 20 minutes, the mixture was rapidly cooled to 30 ° C. to complete the preparation of silver halide emulsion A. did.

[0133] 2. Preparation of Organic Acid Silver Dispersion A 6.1 g of arachidic acid, 37.6 g of behenic acid, 700 ml of distilled water, tert
-Butanol 70ml, 1N-NaOH aqueous solution 123ml mixed, 75 ℃
The mixture was stirred for 1 hour to react, and the temperature was lowered to 65 ° C. Then, 112.5 ml of an aqueous solution of 22 g of silver nitrate was added over 45 seconds, and
It was left for 5 minutes, and the temperature was lowered to 30 ° C. Thereafter, the solid content was separated by suction filtration, and the solid content was washed with water until the conductivity of the filtrate became 30 μS / cm. The solid content thus obtained is treated as a wet cake without drying, and the dry solid content is 100 g.
Considerable wet cake, polyvinyl alcohol
(Product name: PVA-205) Add 5g and water to make the total amount 500
g and then predispersed with a homomixer. Next, the pressure of the predispersed undiluted solution was adjusted to 1750 kg / cm ² by using a dispersing machine (trade name: Microfluidizer M-110S-EH, manufactured by Microfluidics International Corporation, using a G10Z interaction chamber). The treatment was repeated to obtain a silver salt of an organic acid. The organic acid silver particles contained in the organic acid silver dispersion thus obtained have an average minor axis.
Needle-like particles having a particle diameter of 0.04 μm, an average major axis of 0.8 μm, and a variation coefficient of 30% were obtained. Particle size measurements are available from Malvern Instruments Ltd.
Performed with MasterSizerX made by KK. In the cooling operation, a coiled heat exchanger was mounted before and after the interaction chamber, and the temperature of the refrigerant was adjusted to a desired dispersion temperature.
Thus, an organic acid silver dispersion A having a silver behenate content of 85 mol% was prepared.

3. 1,1-bis (2-hydroxy-3,5-dimethyl
Dispersion of solid fine particles of (phenyl) -3,5,5-trimethylhexane
Preparation of the product 1,1-bis (2-hydroxy-3,5-dimethylphenyl) -3,5,5-
To 70 g of trimethylhexane, 14 g of MP-203 of Kuraray Co., Ltd. and 266 ml of water were added and stirred well,
The slurry was left for 3 hours. Thereafter, 960 g of 0.5 mm zirconia silicate beads were prepared, put into a vessel together with the slurry, and dispersed with a dispersing machine (1 / 4G sand grinder mill: manufactured by IMEX Co., Ltd.) for 5 hours to obtain a dispersion of solid fine particles of a reducing agent. Prepared. The particle size is 80 wt% of the particles 0.3
It was not less than μm and not more than 1.0 μm.

[0135] 4. Compound of general formula (I) and general formula
Solid fine particles such as polymers derived from the compound of (II)
Preparation of Particle Dispersion To 30 g of the above compound I-1 was added 4 g of MP-203, an MP polymer manufactured by Kuraray Co., Ltd., 0.25 g of compound C, and 66 g of water, and the mixture was stirred well, and then 0.5 mm zirconia silicate was added. 200 g of beads were prepared, put in a vessel together with the slurry, and dispersed in a disperser (1 / 16G sand grinder mill: manufactured by Imex Co., Ltd.) for 5 hours to prepare a solid fine particle dispersion. As for the particle diameter, 80 wt% of the particles were 0.3 μm or more and 1.0 μm or less. Compounds described in Table 4 other than compound I-1 were dispersed in the same manner as above to prepare solid fine particle dispersions.

[0136] 5. Preparation of solid fine particle dispersion of ultrahigh contrast agent Kuraray Co., Ltd.Poval PVA-
217 2.5 g and 87.5 ml of water were added, and the mixture was stirred well to form a slurry. Thereafter, a solid fine particle dispersion was prepared in the same manner as in 4 above. As for the particle diameter, 80 wt% of the particles were 0.3 μm or more and 1.0 μm or less.

[0137] 6. Preparation of Emulsion Layer Coating Solution With respect to 1 mol of silver of the organic acid silver dispersion A prepared above,
The following binder, material, and silver halide emulsion A were added, and water was added to obtain an emulsion layer coating solution. Binder; Luck Star 3307B 470 g as solids (manufactured by Dainippon Ink and Chemicals, Inc .; glass transition temperature of 17 ° C. with SBR latex) 1,1-bis (2-hydroxy-3,5-dimethylphenyl) -3,5 1,5-trimethylhexane 110 g as solids Phthalazine 17.5 g Tribromomethylphenylsulfone 25 g Sodium benzenethiosulfonate 0.1 g 6-methylbenzotriazole 1.35 g Polyvinyl alcohol (MP-203 manufactured by Kuraray Co., Ltd.) 46 g Dye B 0.62 g Halogen Silver halide emulsion A 0.05 mol as Ag amount Ultra-high contrast agent 8.5 g as solid dispersion B-42 of compound B-42

[0138] 7. Preparation of Coating Solution for Emulsion Surface Protective Layer Polymer latex having a solid content of 27.5 wt% (methyl methacrylate / styrene / 2-ethylhexyl acrylate / 2-
Hydroxyethyl methacrylate / acrylic acid = 59/9
/ 26/5/1 copolymer with a glass transition temperature of 55 ° C) 109 g of H ₂
3.75 g of O, and benzyl alcohol 4.5 as a film forming aid
g, Compound D 0.45 g, Compound E 0.125 g, the compound of general formula (I), the polymer derived from the compound of general formula (II), or the comparative compound of Example 1 as shown in Table 4, and polyvinyl alcohol (Kuraray Co., Ltd., PVA-217) 0.2
85 g and further H ₂ O were added to make 150 g, which was used as a coating solution.

[0139] 8. PET support with backing / priming layer
Preparation of (1) Support PET (intrinsic viscosity) = 0.66 (measured in phenol / tetrachloroethane = 6/4 (weight ratio) at 25 ° C.) using terephthalic acid and ethylene glycol according to a conventional method. Was. After pelletizing this, it was dried at 130 ° C for 4 hours,
After being melted at 00 ° C., the film was extruded from a T-die and quenched to prepare an unstretched film having a thickness of 120 μm after heat setting. This was longitudinally stretched 3.3 times using rolls having different peripheral speeds, and then horizontally stretched 4.5 times using a tenter.
The temperatures at this time were 110 ° C. and 130 ° C., respectively. After that, it was heat-set at 240 ° C. for 20 seconds and relaxed 4% in the lateral direction at the same temperature. Then, after slitting the chuck portion of the tenter, knurling was performed on both ends, and the film was wound at 4.8 kg / cm ² . Thus, width 2.4m, length 3500m, thickness 120
A μm roll was obtained.

(2) Undercoat layer (a) Polymer latex (1) Styrene / butadiene / hydroxyethyl methacrylate / divinylbenzene = 67/30 / 2.5 / 0.5 (% by weight) 160 mg / m ² 2,4-dichloro-6- Hydroxy-s-triazine 4 mg / m ² Matting agent (polystyrene, average particle size 2.4 μm) 3 mg / m ²

(3) Undercoat layer (b) Alkali-treated gelatin (Ca ²⁺ content: 30 ppm, jelly strength: 230 g) 50 mg / m ² Dye B Coating amount at which the optical density of 780 nm becomes 1.0

(4) Conductive layer Julimer ET-410 (manufactured by Nippon Pure Chemical Co., Ltd.) 96 mg / m ² Gelatin 50 mg / m ² Compound A 0.2 mg / m ² Polyoxyethylene phenyl ether 10 mg / m ² Sumitex Resin M -3 18 mg / m ² (water-soluble melamine compound, manufactured by Sumitomo Chemical Co., Ltd.) Dye B Coating amount at which optical density of 780 nm becomes 1.0 SnO ₂ / Sb (9/1 weight ratio, acicular fine particles, long axis / short) Axis = 20-30; manufactured by Ishihara Sangyo Co., Ltd.) 120 mg / m ² Matting agent (polymethyl methacrylate, average particle size 5 μm) 7 mg / m ²

(5) Protective Layer Polymer Latex (2) Methyl methacrylate / styrene / 2-ethylhexyl acrylate / 2-hydroxyethyl methacrylate / acrylic acid = 59/9/26/5/1 (weight% copolymer) 1000 mg / m ² polystyrene sulfonate (molecular weight 1000-5000) 2.6 mg / m ² cellosol 524 (manufactured by Chuo Yushi Co., Ltd.) 30 mg / m ² Sumitex Resin M-3 218 mg / m ² (water-soluble melamine compound, Sumitomo Chemical Industrial Co., Ltd.)

An undercoat layer (a) and an undercoat layer (b) are formed on one side of the support.
Were sequentially applied and dried at 180 ° C. for 4 minutes. Then, a conductive layer and a protective layer are sequentially coated on the opposite side to which the undercoat layer (a) and the undercoat layer (b) have been applied, and dried at 180 ° C. for 30 seconds, respectively, for a PET support having a back / undercoat layer. It was created. With the back / priming layer created in this way
The PET support was placed in a heat treatment zone with a total length of 30 m set at 150 ° C. and transported under its own weight at a tension of 14 g / cm ² and a transport speed of 20 m / min.
Thereafter, the film was passed through a zone at 40 ° C. for 15 seconds, and wound up at a winding tension of 10 kg / cm ² .

9. It was applied so that the emulsion layer coating solution on a PET support undercoat layer equipped with a prepared the back / subbing layer of the heat developable image-forming material on the coated silver amount 1.6 g / m ^2. Further, the coating liquid for the emulsion surface protective layer was applied thereon so that the coating amount of the solid content of the polymer latex was 2.0 g / m ² .

[0146] 10. Evaluation of photographic performance The obtained coated sample was passed through an interference filter having a peak at 780 nm and a step wedge to emit light for 10 hours.
Exposure was performed with xenon flash light for ^-6 seconds. The exposed sample was subjected to a heat development treatment at 117 ° C. for 20 seconds using the heat development machine shown in FIG. In the drum type heat developing machine of FIG. 1, the light distribution of the lamp was optimized, and the temperature control in the width direction was performed at ± 1 ° C. The ambient temperature was adjusted so that the temperature of the heat-developable image forming material did not become 90 ° C. or lower in the vicinity of the correction guide plate 7. Macbeth TD904 densitometer
(Visible density). The measurement results are Dmax, fog
(Dmin), sensitivity (reciprocal of the ratio of the exposure amount giving a density higher than Dmin by 1.5), and gradation (contrast) were evaluated. As for the sensitivity, the sensitivity of Sample No. 204 was set to 100. Contrast was represented by the slope of a straight line connecting points of density 0.3 and 3.0, with the logarithm of the exposure amount as the horizontal axis. An unexposed sample stored at 50 ° C. was also evaluated in the same manner as in Example 1.

[0147]

[Table 4]

(Results) By using a compound derived from the compound of the general formula (I) or the compound of the general formula (II), fluctuations in the sensitivity and the maximum density can be obtained even when the unexposed photosensitive material is stored at a high temperature. Little heat-developed image-forming material was obtained.

[0149]

According to the present invention, it is possible to provide a heat-developable ultrahigh contrast image forming material having high sensitivity, sufficient hardness, excellent storage stability, and suitable for printing plate making.

[Brief description of the drawings]

FIG. 1 is a side view showing a configuration example of a heat developing machine used in the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 halogen lamp 2 heat drum 3 feed roller 4 endless belt 5 heat-developed image forming material 6 outlet 7 guide plate 8 feed roller pair 9 flat guide plate 10 feed roller pair 11 cooling fan

Claims (5)

[Claims] 1. A method comprising: (a) a reducible silver salt, (b) a reducing agent, (c) a binder, and (d) a compound represented by the following general formula (I) on at least one same surface of a support. A heat-developable image-forming material comprising at least one compound. Embedded image [Wherein, M represents a hydrogen atom or a counter ion, Y represents a substituent, L represents a divalent linking group, and B represents a ballast group. m represents an integer of 0 to 4, and n represents an integer of 1 to 4. ] 2. A method comprising: (a) a reducible silver salt, (b) a reducing agent, (c) a binder, and (d) represented by the following general formula (II) on at least one same surface of a support. A heat-developable image-forming material comprising at least one polymer having a repeating unit derived from a compound as a monomer. Embedded image [In the formula, M represents a hydrogen atom or a counter ion, Y represents a substituent, Q represents a group containing at least one carbon-carbon double bond, and m represents an integer of 0 to 4. ] 3. The heat-developable image forming material according to claim 1, further comprising (e) photosensitive silver halide on the same surface. 4. The heat-developable image-forming material according to claim 1, further comprising (f) a super-high contrast agent on the same surface. 5. The super-high contrast agent represented by the general formula (III):
The heat-developable image-forming material according to claim 4, wherein the heat-developable image-forming material is at least one compound selected from the group consisting of compounds represented by formulas (IV) and (V). Embedded image [In the general formula (III), R ¹ , R ² and R ³ each independently represent a hydrogen atom or a substituent, and Z represents an electron-withdrawing group or a silyl group. In the general formula (III), R ¹ and Z, R ² and R ³ , R ¹ and R ² , or R ³ and Z may be bonded to each other to form a cyclic structure. General formula (IV)
In the above, R ⁴ represents a substituent. In the general formula (V), X and Y each independently represent a hydrogen atom or a substituent;
A and B each independently represent an alkoxy group, an alkylthio group, an alkylamino group, an aryloxy group, an arylthio group, an anilino group, a heterocyclic oxy group, a heterocyclic thio group, or a heterocyclic amino group. In the formula (V), X
And Y or A and B may combine with each other to form a cyclic structure. ]