JPH07146537A - Heat developable photoreceptor and image forming method using the same - Google Patents

Abstract

PURPOSE:To obtain a heat developable photoreceptor sensitive to light of wavelength in a red or near IR region from semiconductor laser, LED, etc., almost free from fog and excellent in preservability and to form an image having high image quality with the heat developable photoreceptor. CONSTITUTION:A merocyanine dye having a structure obtd. by combining a 5-membered hetero ring typified by an arom. thiazole, oxazole or selenazole ring with a 5-membered hetero ring typified by a hydantoin or thiazolidone ring through a combining group having a methine chain is incorporated into the photosensitive layer of a heat developable photoreceptor and the resulting photoreceptor is imagewise exposed and heated to form an image.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photothermographic material capable of forming an image by dry processing and an image forming method using the photothermographic material.

[0002]

2. Description of the Related Art The silver salt photographic method using silver halide is a widely used recording technology because of its excellent sensitivity and gradation. However, in order to carry out the process after image exposure by a wet method,
It is inferior in workability, convenience, and safety, and has been a problem until now. On the other hand, research has been conducted on dry-type materials that do not use the wet treatment, and are disclosed in Japanese Patent Publication Nos. 43-4921 and 43-4924. These use a photosensitive silver halide in a catalytic amount and a non-photosensitive organic silver salt as an image forming material. The organic silver salt functions as an image forming material according to the following mechanism. That is, (1) a latent image is formed on a photosensitive silver halide in a catalytic amount by imagewise exposure.
(2) Next, the latent image serves as a catalyst, and the photoreceptor is heated to cause an oxidation-reduction reaction between the organic silver salt and the reducing agent to reduce the organic silver salt to silver, which forms an image. .

The heat-developable photoconductor is used as a light-sensitive material for various industrial purposes such as image communication, medical field, computer output and the like, because it has an advantage that image formation is carried out by a dry process instead of a wet process. Since the heat-developable photoreceptor has silver halide as a photosensitive element, it has high photosensitivity and is easily sensitized in the visible region.

In recent years, semiconductor lasers have been developed and put into practical use that are cheaper, smaller and lighter than gas lasers, and have high efficiency output. Therefore,
By using such an inexpensive, compact, lightweight laser light source and a photothermographic material, a more inexpensive and compact high-performance dry image recording system can be expected.

[0005]

Cyanine dyes have been used in conventional silver halide silver halide photoreceptors for wet processing of gelatin in order to improve the photosensitivity to long-wavelength light, especially red light. However, it has been considered that the cyanine dye is not suitable for a heat-developable photoconductor for dry processing because its sensitizing efficiency is extremely low.

Further, the silver halide photosensitive material for wet processing is
Although the sensitizing dye can be decolorized by a wet process,
The conventional heat-developable photoconductor has a problem that decolorization cannot be sufficiently performed in the heating process and it is difficult to obtain an image having a low minimum optical density. Further, if the addition amount of the sensitizing dye is suppressed in order to lower the minimum optical density, problems of poor sensitivity and poor resolution occur.

Further, the conventional heat-developable photoconductor has a problem that the sensitivity is remarkably lowered when it is stored unused for a long period of time.

Therefore, in order to construct a compact and economical image system, the present invention is sensitive to semiconductor lasers and LEDs having an oscillation wavelength in the red or near infrared region, has almost no fog and is storable. An object of the present invention is to provide a heat-developable photoconductor excellent in heat resistance and an image forming method using the heat-developable photoconductor.

[0009]

The present invention comprises an organic silver salt,
In a heat-developable photoreceptor having a reducing agent and a photosensitive layer containing at least one of a photosensitive silver halide and a photosensitive silver halide-forming agent on a support, in a thiazole nucleus and a selenazole nucleus, Any one of the group consisting of a hydantoin nucleus, a thiohydantoin nucleus and a selenohydantoin nucleus, and a merocyanine dye having a structure in which they are linked by a linking group having a methine chain, wherein the photosensitive layer contains a photothermographic material. A photosensitive member is provided.

The present invention also provides a heat-developable photosensitive layer having on a support a photosensitive layer containing at least an organic silver salt, a reducing agent, and a photosensitive silver halide or a photosensitive silver halide forming agent. In a photosensitive photoreceptor, an oxazole nucleus,
Any one of the group consisting of a thiazole nucleus and a selenazole nucleus, a hydantoinylidene-hydantoin nucleus having 4 substituents, a hydantoinylidene-thiohydantoin nucleus having 4 substituents, and 4 substituents Having a hydantoinylidene-any one of the group consisting of selenohydantoin nucleus, a merocyanine dye having a structure linked by a linking group having a methine chain, the heat-developable photoreceptor characterized in that it contains the photosensitive layer. provide.

The present invention further comprises an organic silver salt, a reducing agent, and
In a heat-developable photoreceptor having a photosensitive layer containing at least one of a photosensitive silver halide and a photosensitive silver halide forming agent on a support, one of an oxazole nucleus and a thiazole nucleus at both ends 1 selected from the group consisting of an oxazolidone nucleus, a thiazolidone nucleus and a dihydroimidazolidone nucleus between the nuclei at both ends.
There is provided a heat-developable photoconductor characterized in that the photosensitive layer contains a merocyanine dye having a structure having two nuclei.

The present invention also provides an image forming method for forming an image by subjecting the above heat-developable photoreceptor to image exposure and heating.

The photothermographic material of the present invention comprises an organic silver salt; a reducing agent; a photosensitive silver halide or a photosensitive silver halide forming agent; and a photosensitive layer containing at least a sensitizing dye on a support. I have.

The sensitizing dyes used in the present invention are as follows.

Sensitizing dye (a) A merocyanine dye having a structure in which a thiazole nucleus or a selenazole nucleus and a hydantoin nucleus, a thiohydantoin nucleus or a selenohydantoin nucleus are linked by a linking group having a methine chain.

Sensitizing dye (b) oxazole nucleus, thiazole nucleus or selenazole nucleus and hydantoinylidene having 4 substituents-hydantoin nucleus, hydantoinylidene having 4 substituents-
A merocyanine dye having a structure in which a thiohydantoin nucleus or a hydantoinylidene-selenohydantoin nucleus having four substituents is linked by a linking group having a methine chain.

Sensitizing dye (c) A structure having an oxazole nucleus or a thiazole nucleus at both ends, and having one nucleus selected from an oxazolidone nucleus, a thiazolidone nucleus and a dihydroimidazolidone nucleus between the nuclei at both ends. Merocyanine dye.

By using any of the above sensitizing dyes (a), (b) or (c), it has excellent sensitivity to light in the red or near infrared region, particularly light having a wavelength of 640 to 750 nm. The fog density is low.

The sensitizing dye (a) will be described in detail below.

The thiazole nucleus is preferably an aromatic thiazole nucleus, particularly preferably a benzothiazole nucleus or a naphthothiazole nucleus, and particularly preferably a naphthothiazole nucleus.

The selenazole nucleus is preferably an aromatic selenazole nucleus, particularly preferably a benzoselenazole nucleus or a naphthoselenazole nucleus, especially a naphthoselenazole nucleus.

Among the hydantoin nucleus, the thiohydantoin nucleus and the selenohydantoin nucleus, the thiohydantoin nucleus and the selenohydantoin nucleus are preferable, and the thiohydantoin nucleus is particularly preferable.

The number of methines in the linking group is preferably 2-8, more preferably 4-6. The methine chain may have a substituent.

As the sensitizing dye (a), those of the following general formula (I) are particularly preferable.

[0025]

[Chemical 2] (In the general formula (I), r ¹ , r ² , r ³ and r ⁴ are each independently a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an alkenyl group, an aralkyl group, a hydroxyl group, an aryl group, a carboxyl group. , An alkoxycarbonyl group,
A cyano group, a trifluoromethyl group, an amino group, an acylamido group, an acyl group, an acyloxyl group, an alkoxycarbonylamino group or a carboalkoxy group, wherein r ¹ and r ² , r ² and r ³ , or r ³ and r ⁴ and Are connected to each other 5
You may form a membered ring or a 6-membered ring. r ⁵ , r ⁶ and r
Each of ⁷ is independently an alkyl group, an alkenyl group, an aryl group or an aralkyl group. r ⁸ , r ⁹ , r ¹⁰ and r
Each ¹¹ independently represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an aryl group or an amino group.
X ¹ represents a sulfur atom or a selenium atom. X ² represents an oxygen atom, a sulfur atom or a selenium atom. m ¹ and n ¹ are 0
It is an integer of 3 and never becomes 0 at the same time. ) R ^{1 to} r ¹¹ may or may not have a substituent. X ¹ and X ² are preferably sulfur atoms.
Each of r ^{1 to} r ⁴ is preferably a hydrogen atom, a halogen atom, an alkyl group, an alkenyl group, an aryl group or an aralkyl group. In particular, it is preferable that r ¹ and r ² or r ³ and r ⁴ are connected to each other to form a naphtho nucleus. The naphtho nucleus may be substituted with an alkyl group or a halogen atom. r ⁵ ~
R ⁷ is preferably an alkyl group. R ^{8 to} r ¹¹ are preferably hydrogen or an alkyl group. m ¹ and n ¹ are preferably integers such that m ¹ + n ¹ = 2.

Preferred examples of the sensitizing dye (a) are shown below.

[0027]

[Chemical 3]

[0028]

[Chemical 4]

[0029]

[Chemical 5]

[0030]

[Chemical 6]

[0031]

[Chemical 7]

[0032]

[Chemical 8]

[0033]

[Chemical 9]

[0034]

[Chemical 10]

[0035]

[Chemical 11] The sensitizing dye (b) will be described in detail below.

The oxazole nucleus is preferably an aromatic oxazole nucleus, particularly preferably a benzoxazole nucleus.

The thiazole nucleus is preferably an aromatic thiazole nucleus, particularly preferably a benzothiazole nucleus.

The selenazole nucleus is preferably an aromatic selenazole nucleus, and particularly preferably a benzoselenazole nucleus.

A hydantoinylidene-hydantoin nucleus having four substituents means a 1,1 ', 3,3'-substituted hydantoinylidene-hydantoin nucleus. The same applies to the hydantoinylidene-thiohydantoin nucleus having 4 substituents and the hydantoinylidene-selenohydantoin nucleus having 4 substituents.

(I) Hydantoinylidene-hydantoin nucleus having 4 substituents, (ii) Hydantoinylidene-thiohydantoin nucleus having 4 substituents, and (iii) Hydan having 4 substituents. Toynylidene
Among the selenohydantoin nuclei, (ii) and (i
ii) is preferable, and (ii) is particularly preferable.

The number of methines in the linking group is preferably 2-8, more preferably 4-6. The methine chain may have a substituent.

As the sensitizing dye (b), those of the following general formula (II) are particularly preferable.

[0043]

[Chemical 12](In the general formula (II), r¹², R¹³, R¹⁴And r¹⁵Is each
Independently, hydrogen atom, halogen atom, alkyl group,
Coxy, alkenyl, aralkyl, hydroxyl
Group, aryl group, carboxyl group, alkoxycarbonyl group
Group, cyano group, trifluoromethyl group, amino group,
Sylamide group, acyl group, acyloxyl group, alkoxy
A carbonylamino group or a carboalkoxy group,
r¹²And r ¹³, R¹³And r¹⁴, Or r¹⁴And r¹⁵And each other
You may connect and may form a 5-membered ring or a 6-membered ring. r¹⁶,
r¹⁷, R¹⁸, R¹⁹And r²⁰Are each independently alkyl
A group, an alkenyl group, an aryl group or an aralkyl group
It r^{twenty one}, R^{twenty two}, R^{twenty three}And r^{twenty four}, Are each independently hydrogen
Atom, halogen atom, alkyl group, alkoxy group, ant
Group or amino group, r^{twenty one}And r^{twenty two}, R^{twenty three}When
r^{twenty four}, R^{twenty one}And r^{twenty three}, Or r^{twenty two}And r^{twenty four}Are connected to each other
To form a ring. X³And X^FourIs an oxygen atom,
Represents an ou atom or a selenium atom. m², N²Is 0 to 3
It is an integer and cannot be 0 at the same time. ) R¹²~ R^{twenty four}May or may not have a substituent
You don't have to. X³And X^FourIs preferably a sulfur atom.
r¹²~ R¹⁵Is a hydrogen atom, a halogen atom, an alkyl group,
Alkenyl, aryl or aralkyl groups are preferred
Yes. In particular, r ¹²And r¹³, Or r¹⁴When¹⁵Are connected and
It is preferable to form soft nuclei. That naphth nucleus is Archi
It may be substituted with a group or a halogen atom. r¹⁶
~ R²⁰Is preferably an alkyl group. r^{twenty one}~ R^{twenty four}Is hydrogen
Or an alkyl group is preferred. m ², n²Is m²+ N²= 2
Is preferred.

Preferred examples of the sensitizing dye (b) are shown below.

[0045]

[Chemical 13]

[0046]

[Chemical 14]

[0047]

[Chemical 15]

[0048]

[Chemical 16]

[0049]

[Chemical 17]

[0050]

[Chemical 18]

[0051]

[Chemical 19]

[0052]

[Chemical 20]

[0053]

[Chemical 21]

[0054]

[Chemical formula 22] The sensitizing dye (c) will be described in detail below.

The oxazole nucleus is preferably an aromatic oxazole nucleus, particularly a benzoxazole nucleus or a naphthoxazole nucleus. The thiazole nucleus is preferably an aromatic thiazole nucleus, especially a benzothiazole nucleus or a naphthothiazole nucleus.

Among the oxazolidone nuclei, thiazolidone nuclei and dihydroimidazolidone nuclei, the oxazolidone nuclei and thiazolidone nuclei are preferable, and the thiazolidone nuclei are particularly preferable.

In the sensitizing dye (c), two linking groups for linking the nuclei are present in one molecule, and both are preferably linking groups having a methine chain. The number of methines in one linking group is preferably 1-5. When the number of methines in one linking group is an even number in one molecule, the number of methines in the other linking group is preferably an odd number.

As the sensitizing dye (c), those of the following general formula (III) are particularly preferable.

[0059]

[Chemical formula 23] (In the general formula (III), A ₁ ⁻ is a substituted or unsubstituted alkyl sulfonate ion, a substituted or unsubstituted aromatic sulfonate ion, NO ₃ ⁻ , Cl ⁻ , Br ⁻ , I ⁻ or C
lO ₄ ^- is. X ⁵ is a substituted or unsubstituted imino group. Y ¹ and Y ² are oxygen atoms or sulfur atoms. r ³¹ and r ³² are a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted aralkyl group. Z ¹ is an oxygen atom, a sulfur atom, a selenium atom or a substituted or unsubstituted imino group. r ³³ , r ³⁴ , r ³⁵ , r ³⁶ and r ³⁷ are a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, an alkoxy group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted amino group. is there. A ring may be formed by r ³³ and r ³⁴ , r ³⁶ and r ³⁷ , r ³⁵ , r ³⁶ and r ³⁷ . m ³ and n ³ are integers in the range of 1-3. ) R ³¹ and r ³² are preferably alkyl groups, particularly ethyl groups. Each of r ^{33 to} r ³⁷ is preferably a hydrogen atom or an alkyl group. m ³ and n ³ are preferably integers such that m ³ + n ³ = 2 to 4.

Preferred examples of the sensitizing dye (c) are shown below.

[0061]

[Chemical formula 24]

[0062]

[Chemical 25]

[0063]

[Chemical formula 26]

[0064]

[Chemical 27]

[0065]

[Chemical 28]

[0066]

[Chemical 29]

[0067]

[Chemical 30] As the organic silver salt, "basics of photographic engineering" (edited by The Photographic Society of Japan, Corona Publishing Co., Ltd., Tokyo, 1st edition, 1982)
Non-silver salt edition, p247, organic acid silver salts described in JP-A-59-55429, triazole silver salts and the like can be used, and silver salts having low photosensitivity are preferably used. Examples thereof include silver salts of aliphatic carboxylic acids, aromatic carboxylic acids, thiols, thiocarbonyl compounds having α-hydrogen, and imino group-containing compounds.

As the aliphatic carboxylic acid, acetic acid, butyric acid,
There are succinic acid, sebacic acid, adipic acid, oleic acid, linoleic acid, linolenic acid, tartaric acid, palmitic acid, stearic acid, behenic acid, camphoric acid, etc. A compound having an appropriate carbon number (for example, a carbon number in the range of 16 to 26) is preferable because it is stable.

Examples of aromatic carboxylic acids include benzoic acid derivatives, quinolinic acid derivatives, naphthalenecarboxylic acid derivatives,
Salicylic acid derivative, gallic acid, tannic acid, phthalic acid,
Examples include phenylacetic acid derivatives and pyromellitic acid.

Examples of the thiocarbonyl compound having thiol or α-hydrogen include 3-mercapto-4-phenyl-1,2,4-triazole, 2-mercaptobenzimidazole, 2-mercapto-5-aminothiadiazole and 2-mercapto. Benzothiazole, S-alkyl thioglycolic acid (alkyl group having 12 to 23 carbon atoms),
Dithiocarboxylic acids such as dithioacetic acid, thioamides such as thiostearoamide, 5-carboxy-1-methyl-2-phenyl-4-thiopyridone, mercaptotriazine, 2-mercaptobenzoxazole, mercaptooxathiazole or 3-amino- 5-benzylthio-1,2,4-triazole and the like, US Pat.
The mercapto compound described in No. 3,274 can be mentioned.

As the compound containing an imino group, benzotriazole or its derivative described in JP-B-44-30270 or 45-18416, for example, alkyl-substituted benzotriazoles such as benzotriazole and methylbenzotriazole, 5-chlorobenzotriazole, etc. Halogen-substituted benzotriazoles, butylcarbimidobenzotriazole and other carboimide benzotriazoles, nitrobenzotriazoles described in JP-A-58-18639, and JP-A-58-11563.
No. 8, sulfobenzotriazole, carboxybenzotriazole or a salt thereof, hydroxybenzotriazole and the like, 1,2,4-triazole described in US Pat. No. 4,220,709, 1H-tetrazole, carbazole, saccharin, imidazole and derivatives thereof. Can be mentioned as a representative example.

As the reducing agent, all materials (preferably organic materials) capable of reducing silver ions to metallic silver can be used.

Examples of such reducing agents include monophenols, bisphenols, trisphenols, tetrakisphenols, mononaphthols, bisnaphthols, dihydroxynaphthalenes, sulfonamidephenols, biphenols and trihydroxynaphthalenes. , Dihydroxybenzenes, trihydroxybenzenes, tetrahydroxybenzenes, hydroxyalkyl monoethers, ascorbic acids, 3-pyrazolidones, pyrazolones, pyrazolines, sugars, phenylenediamines, hydroxyamines, reductones, hydrooxa Examples thereof include mic acids, hydrazines, hydrazides, amidoximes, N-hydroxyureas and the like. Among these, especially p-bisphenols and o-
Bisphenols, bisnaphthols, 4-substituted naphthols and the like are preferable. In addition, JP-A-3-135564
The reducing agent described in the publication is also preferably used.

Examples of the photosensitive silver halide include silver chloride, silver bromide, silver chlorobromide, silver iodobromide, silver chloroiodobromide and the like.

As a method for preparing these silver halides, a part of the silver oxide compound is halogenated with a photosensitive silver halide-forming component such as ammonium bromide, lithium bromide, sodium chloride or N-bromosuccinimide. And a so-called external silver halide is contained.

The shape of these silver halide crystals may be cubic, octahedral or tabular, and cubic or tabular silver halide is particularly preferred. The length of one side of the cubic silver halide crystal is preferably 0.01 to 2 μm, more preferably 0.02 to 1.3 μm. The tabular silver halide has an average aspect ratio of preferably 100: 1 to 3: 1, more preferably 50: 1 to 5: 1, and its grain diameter is preferably 0.01 to 2 µm, more preferably 0. .02
Is about 1.3 μm.

The silver halide crystal surface layer may contain iridium. The crystal surface layer is a layer from the crystal surface of silver halide to a predetermined depth.
In this case, the crystal form of silver halide is preferably a tetragonal form of {100} plane. One side of the silver halide grain is 0.
001 μm to 1.0 μm is preferable, and further 0.0
1 μm to 0.2 μm is preferable, and 0.03 μm to 0.1 μm is particularly preferable. The thickness of the crystal surface layer containing iridium ions is 10% or less of the length of one side of the crystal,
Furthermore, 5% or less is preferable. The crystal surface layer containing iridium ions is preferably at least 0.5% or more of the length of one side of the crystal.

To prepare a silver halide containing iridium ions, an iridium ion supplier may be added when silver halide is produced from the reducible organic silver salt and the silver halide-forming component. As the iridium ion supplier, for example, iridium tetrachloride, iridium (IV) hexachloride potassium, iridium (IV) hexachloride sodium and the like are preferable.

In order to contain iridium ions in the silver halide crystal surface layer, an iridium ion supplier may be introduced after a short time has elapsed from the start of silver halide production. For example, silver halide is 90% by weight of the specified amount
It is sufficient to start feeding the iridium ion supplier at the time of generation.

All of the silver halide used in the present invention are
It may contain iridium ions, or may be a mixture of silver halide containing iridium ions and silver halide not containing iridium ions.

The content of iridium ions is 1 × 10 ^-8 mol to 1 × 10 ^-4 mol, more preferably 1 × 10 ^-7 mol to 1 × 10, per 1 mol of total silver halide contained in the photosensitive layer.
A ratio of ^-6 mol is preferred.

The heat-developable photosensitive material of the present invention may further contain a cyanine dye of the following general formula (IV). By containing the cyanine dye of the general formula (IV), the storage stability in the unused state is improved and the resolution is also improved.

[0083]

[Chemical 31](In the general formula (IV), r⁴¹, R⁴², R⁴³, R⁴⁴, R⁴⁷,
r⁴⁸, R⁴⁹, R⁵⁰Are each independently a hydrogen atom or a halogen atom.
Child, alkyl group, alkoxy group, aryl group or amino group
R group⁴¹And r⁴², R⁴²And r⁴³, R⁴³And r⁴⁴,
r⁴⁷And r⁴⁸, R ⁴⁸And r⁴⁹, R⁴⁹And r⁵⁰One of
And may form a ring. r⁵¹, R ⁵², R⁵³,
r⁵⁴, R⁵⁵Are each independently a hydrogen atom, an alkyl group or
An aryl group, r⁵¹And r⁵³, R⁵²And r⁵⁴, R⁵³And r
⁵⁵May combine with each other to form a ring. r ⁴⁵And r⁴⁶Is each
Independently, it is an alkyl group or an aralkyl group. Y³Oh
And Y^FourIs an oxygen atom, a sulfur atom, a carbon atom or nitrogen
Atomic, hydrogen in the case of carbon or nitrogen
Any of atom, alkyl group, aryl group, aralkyl group
Are connected. A₂ ^-Is an anion. m^Four, N^FourIs
0, 1 or 2. ) A₂ ^-For example, bromine, iodine, chlorine, perchlorine
Acid, tetrafluoroborate, toluene sulphonate
And arsenic hexafluoride are preferred. Y³And Y^FourAs
Is preferably an oxygen atom or a nitrogen atom.

[0084] r ^45, r ⁴⁶ is carboxyalkyl group, when having an anion such as sulfonic acid group, A ₂ ^-
May not exist.

It is preferable that m ⁴ and n ⁴ are not 0 at the same time, and further, m ⁴ + n ⁴ is 2.

Preferred examples of the cyanine dye represented by the general formula (IV) are shown below.

[0087]

[Chemical 32]

[0088]

[Chemical 33]

[0089]

[Chemical 34]

[0090]

[Chemical 35]

[0091]

[Chemical 36]

[0092]

[Chemical 37]

[0093]

[Chemical 38]

[0094]

[Chemical Formula 39]

[0095]

[Chemical 40] The photosensitive layer preferably contains a binder for the purpose of improving the film properties and dispersibility of the photosensitive layer. Examples of binders include nitrocellulose, cellulose phosphate,
Cellulose sulfate, cellulose acetate, cellulose propionate, cellulose butyrate, cellulose myristate, cellulose palmitate, cellulose acetate / propionate,
Cellulose esters such as acetic acid and cellulose butyrate;
Ethers of cellulose such as methyl cellulose, ethyl cellulose, propyl cellulose, butyl cellulose; polystyrene, polyvinyl chloride, polyvinyl acetate,
Polyvinyl butyral, polyvinyl acetal, polyvinyl alcohol, polyvinylpyrrolidone and other vinyl polymers; styrene-butadiene copolymer, styrene-
Acrylonitrile copolymer, styrene-butadiene-
Acrylonitrile copolymers, copolymers such as vinyl chloride-vinyl acetate copolymers; acrylic polymers such as polymethylmethacrylate, polymethylacrylate, polybutylacrylate, polyacrylic acid, polymethacrylic acid, polyacrylamide, polyacrylonitrile; polyethylene terephthalate Polyesters such as poly (4,4-isopropylidene-diphenylene-)
Co-1,4-cyclohexylene dimethylene carbonate), poly (ethylenedioxy-3,3'-phenylene thiocarbonate), poly (4,4'-isopropylidene diphenylene carbonate-co-terephthalate),
Poly (4,4'-isopropylidenediphenylene carbonate), poly (4,4'-sec-butylidenephenylene carbonate), poly (4,4'-isopropylidenediphenylene carbonate-block-oxyethylene), etc. Acrylate polymers; Polyamides;
Examples thereof include polyimides; epoxy polymers; phenol polymers; polyolefins such as polyethylene, polypropylene and chlorinated polyethylene; and natural or synthetic resins such as gelatin.

Particularly preferred are polyvinyl acetals such as polyvinyl butyral and polyvinyl formal, and vinyl copolymers such as vinyl chloride vinyl acetate copolymer.

The heat-developable photosensitive material of the present invention may further contain a thiol compound represented by the following general formula (V) or (VI). The heat-developable photoreceptor of the present invention has the general formula (V)
You may contain both thiol compounds of and (VI). By containing the thiol compound represented by the general formula (V) or (VI), sensitivity and storability in an unused state are improved. Further, temperature control during heat development is relaxed (that is, the heat development latitude is widened).

[0098]

[Chemical 41]

[0099]

[Chemical 42] (In the general formulas (V) and (VI), R ^{1 to} R ¹⁰ are a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a carboxyl group, a substituted or unsubstituted aryl group, sulfonic acid Represents a group, a substituted or unsubstituted amino group, a nitro group, a halogen atom, an amido group, an alkenyl group or an alkynyl group, R ¹ and R ² , R ² and R ³ , R ³
And R ⁴ may each form a condensed ring. X ¹⁰
And X ¹¹ are each independently —O—, —N (R ¹¹ ) —,
Alternatively, it represents —S—, and R ¹¹ represents hydrogen, an alkyl group or an aryl group. ) Suitable examples of the thiol compounds represented by the general formulas (V) and (VI) are shown below.

[0100]

[Chemical 43]

[0101]

[Chemical 44]

[0102]

[Chemical formula 45]

[0103]

[Chemical formula 46]

[0104]

[Chemical 47]

[0105]

[Chemical 48]

[0106]

[Chemical 49]

[0107]

[Chemical 50]

[0108]

[Chemical 51]

[0109]

[Chemical 52]

[0110]

[Chemical 53]

[0111]

[Chemical 54]

[0112]

[Chemical 55]

[0113]

[Chemical 56] The photoconductor of the present invention may contain a toning agent, if necessary. As the color toning agent, for example, US Pat.
Examples thereof include phthalazinone or a derivative thereof described in JP-A No. 0254, cyclic imides described in JP-A-46-6074, and phthalazinone compound described in JP-A-50-32927.

The photoconductor of the present invention may contain an organic acid, if necessary, in order to improve the color tone of the image and the stability after the image is formed. In particular, a long chain fatty acid may be used alone or in combination. It is preferably contained.

In the heat-developable photosensitive material of the present invention, the preferable compounding ratio of each component is as follows.

The content of the organic silver salt is 5 to the photosensitive layer.
70% by weight, further 10 to 60% by weight, especially 20 to 50
Weight percent is preferred. Even when the photosensitive layer is composed of multiple layers as described later, the content of the organic silver salt is the above value with respect to the entire photosensitive layer.

The content of the reducing agent is preferably 0.05 to 3 mol, more preferably 0.2 to 2 mol, per 1 mol of the organic silver salt.

Further, it is desirable that the photosensitive silver halide is contained in an amount of preferably 0.001 to 2 mol, more preferably 0.05 to 1 mol per mol of the organic silver salt. Further, in the present invention, a silver halide forming agent (for example, a halogen compound such as tetrabutylammonium bromide, N-bromosuccinimide, bromine or iodine) may be used in place of silver halide. The content of the silver forming agent can be considered as in the case of silver halide.

The content of the sensitizing dyes represented by formulas (I) to (III) is 1 × 10 ^-5 to 1 per mol of the organic silver salt.
A range of ^{x10 -2} mol, particularly a range of 1 x 10 ^-4 to 1 x 10 ^-3 mol is preferable.

The content of the cyanine dye of the general formula (IV), which is contained as necessary, is also 1 × 10 per mol of the organic silver salt.
^-5 to 1 × 10 ^-2 mol, particularly 1 × 10 ^-4 to 1 × 10 ^-3 mol is preferable.

The content of the thiol compound represented by the general formula (V) or (VI), which is contained as necessary, is 1 with respect to 1 mol of the sensitizing dye represented by the general formulas (I) to (III). 0.0 × 10 ^{−1 to} 2.0 × 10 ² mol, further 5.0 × 10 ^{−1 to} 1.0 × 10 ² mol, and especially 1.0 to
The range of 8.0 × 10 mol is preferable.

The content of the binder, which is contained as necessary, is preferably 0.5 to 10 parts by weight, more preferably 0.5 to 5 parts by weight, based on 1 part by weight of the organic silver salt.

If necessary, the content of the organic acid contained is
The amount is 25 mol% to 200 mol%, and particularly preferably 30 mol% to 120 mol% with respect to the organic silver salt.

The content of the toning agent contained as necessary is as follows:
The amount is preferably 0.01 to 5 mol, more preferably 0.05 to 2 mol, and particularly preferably 0.08 to 1 mol, per 1 mol of the organic silver salt.

Further, the photoreceptor of the present invention may contain a suitable antifoggant, if necessary. Examples of the antifoggant include a mercury compound described in JP-B-47-11113, a 1,2,4-triazole compound described in JP-B-55-42375, and JP-A-57.
-30828, a tetrazole compound, JP-A-57-138630, benzoic acids, JP-A-57-147627, a compound having a sulfonylthio group, and JP-A-58-107534. And dibasic acids of the above. Particularly, dibasic acids described in JP-A-58-107534 are preferable.

The photoconductor of the present invention may contain an anti-coloring agent, if necessary, in order to prevent coloring of the non-image area due to light after image formation. As the anti-coloring agent, for example, the compounds described in JP-A No. 61-129642 are preferable.

The photoconductor of the present invention may further contain a development accelerator, if necessary. Examples of preferable development accelerators include alkali metal salt compounds of fatty acids described in JP-B No. 64-8809.

The photoreceptor of the present invention may contain an antistatic agent, if necessary. Also, Japanese Patent Laid-Open No. 64-2
The fluorine-containing surfactant and the nonionic surfactant described in Japanese Patent No. 4245 may be contained in combination.

The photoreceptor of the present invention may contain an ultraviolet absorber, an antihalation dye (layer), an antiirradiation dye, a matting agent and a fluorescent brightening agent, if necessary.

The heat-developable photosensitive material of the present invention can be obtained by forming a photosensitive layer containing the above-mentioned various components in a single layer or a multilayer on an appropriate support. When the photosensitive layer has a multilayer structure, organic silver salts, silver halides, and general formulas (I) to (I
It is preferable to have a multi-layer structure with the layer containing the sensitizing dye represented by II). The thiol compound of the general formula (V) or (VI) optionally contained is contained in the layer containing the sensitizing dye.

Examples of the support include synthetic resin films such as polyethylene, polypropylene, polyethylene terephthalate, polycarbonate, and cellulose acetate, synthetic paper, paper covered with synthetic resin film such as polyethylene, art paper, and photographic paragraph paper. Examples thereof include papers, metal plates (foil) such as aluminum, synthetic resin films having metal vapor deposition films, and glass plates.

A protective layer may optionally be provided on the photosensitive layer in order to increase the transparency of the photothermographic material, increase the image density, improve the raw storability and, in some cases, the heat resistance of the photosensitive material. Can be provided. The thickness of the protective layer is 1 to 20μ
m is suitable. If it is thinner than this, the above effects are lost, and if it is too thick, there is no special advantage and only the cost is increased. The polymer used for the protective layer is preferably heat-resistant, colorless and easily soluble in a solvent, such as polyvinyl chloride, polyvinyl acetate, a copolymer of vinyl chloride and vinyl acetate (preferably vinyl chloride is 50 mol% or more), polyvinyl butyral, polystyrene, polymethylmethacrylate, benzyl cellulose, ethyl cellulose, cellulose acetate butyrate, cellulose diacetate, cellulose triacetate, polyvinylidene chloride, chlorinated polypropylene, polyvinylpyrrolidone, cellulose propionate, Polyvinyl formal, cellulose acetate butyrate, polycarbonate, cellulose acetate propionate, gelatin,
Examples thereof include gelatin derivatives such as phthalated gelatin, acrylamide polymers, polyisobutylene, butadiene-styrene copolymers (arbitrary monomer ratio), polyvinyl alcohol and the like. In addition to these binders, colloidal silica may be contained in the protective layer.

Polymers preferable for the protective layer have a heat resistance of 115 ° C. or higher and a refractive index of 1.45 or higher at 20 ° C.

When each layer having various functions such as a photosensitive layer and a protective layer is separately formed in the heat-developable photoreceptor of the present invention, each of these layers can be coated by various coating methods. Examples of the method for forming each layer include a dipping method, an air knife method, a curtain coating method, and an extrusion coating method using a hopper described in US Pat. No. 2,681,294. If desired, two or more layers can be coated simultaneously.

The heat-developable photosensitive material of the present invention is a metallic silver produced by the reaction of an organic silver salt and a reducing agent by an oxidation-reduction reaction in the image-exposed portion by image exposure and heating (heat development). To form a blackened image.

The heat-developable photoconductor of the present invention utilizes the light absorbing property of the oxidant (oxidized by the reducing agent) produced by the above-mentioned redox reaction to form a pattern due to the difference in the light absorbing property. It can also be formed. That is, due to the difference in light absorption property, light having a specific wavelength is absorbed in the portion where the oxidant is generated (image exposed portion), and light is less absorbed in the portion where the oxidant is not generated (image unexposed portion). A pattern can be formed.

By utilizing the above-mentioned difference in light absorption property, the heat-developable photosensitive material of the present invention forms a pattern composed of a polymerized portion and an unpolymerized portion (hereinafter referred to as a polymerized / non-polymerized pattern).
Can also be formed. That is, it is possible to form a polymerized / unpolymerized pattern by imagewise exposure, heat development and polymerization exposure by incorporating a polymerizable polymer precursor and a photopolymerization initiator in the photosensitive layer according to the present invention. In this way, the polymerized / unpolymerized pattern is formed because the light does not proceed in the image-exposed area due to light absorption by silver or an oxidant generated by the oxidation / reduction reaction during thermal development, and This is because polymerization proceeds in the part.

The polymerizable polymer precursor and the photopolymerization initiator may be contained in the photosensitive layer, but a polymerization layer containing the polymerizable polymer precursor and the photopolymerization initiator is provided separately from the photosensitive layer. May be.

The photosensitive layer and the polymerized layer are the polymerized layer from the support side,
The photosensitive layers may be laminated in this order, or the photosensitive layer and the polymer layer may be laminated in this order from the support side, or the photosensitive layer may be provided on one side of the support and the polymer layer may be provided on the other side with the support interposed therebetween. May be.

In the present invention, the thickness of the photosensitive layer is 0.1 μm.
m to 50 μm, further 1 μm to 30 μm, especially 2 μm
˜20 μm is preferred. When the photosensitive layer has a multilayer structure,
The thickness of each layer forming the photosensitive layer may be substantially equal to each other.

Next, a method for forming an image using the photoconductor of the present invention will be described.

Since the photosensitive material of the present invention contains the sensitizing dyes represented by the general formulas (I) to (III) described above, it exhibits good photosensitivity and heat developability, and at the same time in the red and near infrared regions. It has high sensitivity. Therefore, for the photoreceptor of the present invention, semiconductor laser light or LED light, especially 640 nm
When image exposure according to a desired image is performed with light of ˜750 nm,
A silver nucleus is generated and a latent image can be formed first. Further, by subjecting this to appropriate heating (heat development), an image corresponding to image exposure can be developed by a redox reaction.

The image forming method of the present invention for forming an image in this way is not only easy to handle in processing and convenient for mechanization, but also semiconductor laser or L laser.
Since ED light can be used, it is a compact and economical method. According to the photoreceptor of the present invention, the image exposure speed is 1 × 10 ⁻⁵ sec / dot to 1 × 10 ⁻⁷ sec / dot.
The problem of reciprocity law failure does not occur even for a short time of dot.

Furthermore, in the heat-developable photoreceptor of the present invention containing a polymerizable polymer precursor and a photopolymerization initiator, after the image exposure and the heat development described above, polymerization is performed on the entire surface of the heat-developable photoreceptor from the side of the photosensitive layer. By exposing, a polymerized / unpolymerized pattern can be formed.

As the light source used in the polymerization exposure process, for example, sunlight, tungsten lamp, mercury lamp, halogen lamp, xenon lamp, fluorescent lamp, LED, laser beam and the like can be used.

The wavelength of the light for polymerization exposure may be the same as or different from the wavelength of the light for image exposure. Even when light having the same wavelength as in the case of image exposure is used, photosensitive silver halide usually has a sufficiently higher photosensitivity than a photopolymerization initiator, so that photopolymerization does not occur in the image exposure process. A latent image can be written with intense light. For example, in the image exposure process, approximately 100 .mu.J / cm ² on the surface of the photosensitive member, preferably 30μJ / cm ^2, more preferably subjected to exposure with light of up to 15μJ / cm ^2, the polymerization exposure step, the surface of the photosensitive member The exposure may be performed with light up to about 500 mJ / cm ² . Even when polymerization exposure is not performed, the image exposure process is performed under the above conditions.

There are various means for heating and developing the photoconductor of the present invention. For example, the photoconductor may be brought into contact with a simple heating plate or the like, or may be brought into contact with a heated drum, and may be heated in some cases. You may pass through the space. Moreover, you may heat by a high frequency heating or a laser beam. The heating temperature is 80 ℃ -160 ℃, moreover 1
00 ° C to 160 ° C is suitable, and more preferably 110 ° C.
C to 150C. By extending or shortening the heating time, higher or lower temperature can be used within the above range. Development time is usually 1 to 60
Seconds, preferably 3 to 20 seconds.

As described above, the present invention is applicable to semiconductor lasers and LEs having an oscillation wavelength in the red or near infrared region.
A heat-developable photoconductor that has excellent sensitivity to D and the like, has no problem of reciprocity law failure even when exposed to high illuminance by a laser or the like, has almost no fog, and gives an image of good quality. Is obtained. The heat-developable photoconductor of the present invention has excellent storage stability.

[0149]

EXAMPLES The present invention will be described in more detail with reference to examples.

Example 1 A photosensitive composition having the following composition was prepared under safe light.

Polyvinyl butyral 5.0 g Silver behenate 2.5 g Behenic acid 2.0 g Silver bromide 0.2 g Phthalazinone 1.0 g 2,2′-methylenebis (6-t-butyl-4-methylphenol) 1.0 g Xylene 30 ml n-Butanol 30 ml The above silver bromide was a cubic crystal having a crystal face index of {100}, and the average length of one side was 0.07 μm.

5 mg of the above-mentioned sensitizing dye (I-7) was added to N, N
Dissolved in 5 ml of dimethylformamide (DMF) and added the solution to the above photosensitive composition.

The above-mentioned photosensitive composition containing the sensitizing dye (I-7) was coated on a polyethylene terephthalate (PET) film so as to have a dry film thickness of 10 μm to form a photosensitive layer, which was then dried as a protective layer. A polyvinyl alcohol layer having a film thickness of 2 μm was applied to obtain a heat developable photoreceptor of the present invention.

With respect to the heat-developable photoconductor thus obtained, the sensitivity and fog density immediately after preparation of the photoconductor and the sensitivity and fog density after long-term storage in an unused state were measured.
The storage condition was 72 hours under the environment of 50 ° C. and 80% RH.

The sensitivity and fog density are the transmission optical density (O.E.) of the image formed by forming an image on the photothermographic material.
D. ) Was measured.

That is, in the present invention, the transmission optical density when the image exposure energy is 0.1 μJ / cm ² is the fog density. The sensitivity was defined as the image exposure energy value required to obtain a transmission optical density obtained by adding 0.5 to the fog density. Therefore, the sensitivity is obtained from the characteristic curve of the transmission optical density with respect to the image exposure energy and the fog density.

A transmission / reflection color densitometer NLM-STD-Tr (manufactured by Narumi Shokai) was used for the measurement of the transmission optical density.

For image formation, the heat-developable photoconductor is used at a wavelength of 670.
image exposure with a semiconductor laser of 10 nm, and then heat development for 10 seconds in a heat developing machine set at 118 ° C. The spot diameter of the semiconductor laser was 20 μm × 40 μm, and the exposure speed was 1.67 × 10 ⁻⁷ sec / dot.

The characteristic curve of the transmission optical density with respect to the image exposure energy was prepared by changing the image exposure energy to form an image and measuring the transmission optical density of the obtained image.

The sensitivity and fog density thus obtained are shown in Table 1.

The resolution of the heat-developable photoconductor prepared as described above was evaluated as follows.

First, with respect to the heat-developable photoconductor, the wavelength 68
300nm, 600 by 0nm semiconductor laser
Image exposure was performed at a resolution of dpi and 900 dpi, and then heat development was performed for 10 seconds in a heat developing machine set at 120 ° C. to form an image. The spot diameter of the semiconductor laser is 20μ
m × 40 μm, exposure speed is 1.67 × 10 ⁻⁷ se
c / dot. The energy of image exposure was 30 μJ / cm ^{2 on the} surface of the photoconductor.

Next, with respect to the image thus obtained, the transmission optical density of the image-exposed portion and the transmission optical density of the non-image-exposed portion between the image-exposed portions were measured to evaluate the resolution of the image. . The transmission optical density in the resolution evaluation was measured at a wavelength of 55 using a microspectrophotometer UMSP manufactured by KARL TWICE.
It was performed with 0 nm ± 5 nm light. Table 2 shows the measurement results of resolution
It was shown to.

(Example 2) The present invention was carried out in the same manner as in Example 1 except that the above-mentioned sensitizing dye (II-2) was used in place of the sensitizing dye (I-7) used in Example 1. A heat-developable photoconductor of was prepared.

Using this heat-developable photoreceptor, the sensitivity and fog density were measured in the same manner as in Example 1. The measurement results are shown in Table 1. The resolution of this heat-developable photoconductor was measured in the same manner as in Example 1. Table 2 shows the measurement results
It was shown to.

Example 3 The present invention was carried out in the same manner as in Example 1 except that the sensitizing dye (III-3) was used instead of the sensitizing dye (I-7) used in Example 1. A heat-developable photoconductor of was prepared.

Using this heat-developable photoreceptor, the sensitivity and fog density were measured in the same manner as in Example 1. The measurement results are shown in Table 1. The resolution of this heat-developable photoconductor was measured in the same manner as in Example 1. Table 2 shows the measurement results
It was shown to.

(Comparative Examples 1 to 3) Instead of the sensitizing dye (I-7) used in Example 1, the following sensitizing dye (R-1),
Three types of heat-developable photoconductors were produced in the same manner as in Example 1 except that (R-2) or (R-3) was used.

Using these heat-developable photoconductors, the sensitivity and the fog density were measured in the same manner as in Example 1. The measurement results are shown in Table 1. The sensitizing dye used was (R-
The case of 1) is Comparative Example 1, the case of (R-2) is Comparative Example 2,
The case of (R-3) is referred to as Comparative Example 3.

[0170]

[Chemical 57]

[0171]

[Chemical 58]

[0172]

[Chemical 59] (Example 4) A photosensitive composition having the following composition was prepared under safe light.

Polyvinyl butyral 3.0 g Silver behenate 2.5 g Behenic acid 1.5 g Silver bromide 0.6 g Homophthalic acid 0.6 g Phthalazinone 0.5 g 2,2′-methylenebis (4,6-di-t-butylphenol) ) 2.6 g Xylene 30 ml n-Butanol 40 ml The above silver bromide was a cubic crystal having a crystal face index of {100}, and the average length of one side was 0.06 μm.

1.5 mg of the sensitizing dye (I-7) and 5 mg of the cyanine dye (IV-4) were dissolved in 10 ml of N, N-dimethylformamide (DMF), and the solution was added to the above-mentioned photosensitive composition. did.

The above photosensitive composition containing the sensitizing dye (I-7) and the cyanine dye (IV-4) was dried on a polyethylene terephthalate (PET) film to give a dry film thickness of 10
A heat-developable photoreceptor of the present invention was obtained by applying a polyvinyl alcohol layer having a dry film thickness of 2 μm as a protective layer on the photosensitive layer by coating so as to have a thickness of μm.

Using this heat-developable photoconductor, the sensitivity and fog density were measured in the same manner as in Example 1. The measurement results are shown in Table 1. The resolution of this heat-developable photoconductor was measured in the same manner as in Example 1. Table 2 shows the measurement results
It was shown to.

Example 5 The present invention was carried out in the same manner as in Example 4 except that the above sensitizing dye (II-2) was used in place of the sensitizing dye (I-7) used in Example 4. A heat-developable photoconductor of was prepared.

Using this heat-developable photoreceptor, the sensitivity and fog density were measured in the same manner as in Example 1. The measurement results are shown in Table 1. The resolution of this heat-developable photoconductor was measured in the same manner as in Example 1. Table 2 shows the measurement results
It was shown to.

Example 6 The present invention was carried out in the same manner as in Example 4 except that the above sensitizing dye (III-3) was used in place of the sensitizing dye (I-7) used in Example 4. A heat-developable photoconductor of was prepared.

Using this heat-developable photoreceptor, the sensitivity and fog density were measured in the same manner as in Example 1. The measurement results are shown in Table 1. The resolution of this heat-developable photoconductor was measured in the same manner as in Example 1. Table 2 shows the measurement results
It was shown to.

[0181]

[Table 1]

[0182]

[Table 2] As is clear from Table 1, the heat-developable photoreceptor of the present invention is
Higher sensitivity and lower fog density than conventional heat-developable photoconductors.

Further, as is clear from Table 2, the resolution is improved when the cyanine dye is used in combination.

[0184]

As described above, according to the present invention, a heat-developable photosensitive material which is exposed to a semiconductor laser or an LED having an oscillation wavelength in the red or near infrared region, has almost no fog and is excellent in storage stability. A body can be obtained, and an image of high quality can be obtained by forming an image using the photothermographic material.

Front page continuation (72) Inventor Kazunori Ueno 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Motokazu Kobayashi 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Kenji Kagami 1-24-40 Minamihara, Hiratsuka-shi, Kanagawa Oriental Photography Industry Co., Ltd. (72) Inventor Masao Suzuki 1-24-40, Minamihara, Hiratsuka-shi, Kanagawa Oriental Photography Industry Co., Ltd. (72) Inventor Katsuya Nishino 1-24-40 Minamihara, Hiratsuka-shi, Kanagawa Oriental Photography Industry Co., Ltd.

Claims (21)

[Claims] 1. A heat-developable photoreceptor having on its support a photosensitive layer containing at least one of an organic silver salt, a reducing agent, and a photosensitive silver halide and a photosensitive silver halide forming agent. In the above, the merocyanine dye having a structure in which any one of a thiazole nucleus and a selenazole nucleus and any one of a group consisting of a hydantoin nucleus, a thiohydantoin nucleus and a selenohydantoin nucleus is linked by a linking group having a methine chain, A heat-developable photoconductor characterized by being contained in. 2. The photothermographic material according to claim 1, wherein the thiazole nucleus is an aromatic thiazole nucleus. 3. The photothermographic material according to claim 2, wherein the aromatic thiazole nucleus is one of a benzothiazole nucleus and a naphthothiazole nucleus. 4. The photothermographic material according to claim 1, wherein the selenazole nucleus is an aromatic selenazole nucleus. 5. The photothermographic photoreceptor according to claim 4, wherein the aromatic selenazole nucleus is one of a benzoselenazole nucleus and a naphthoselenazole nucleus. 6. A heat-developable photoreceptor having on its support a photosensitive layer containing at least an organic silver salt, a reducing agent, and a photosensitive silver halide or a photosensitive silver halide forming agent. In any one of the group consisting of an oxazole nucleus, a thiazole nucleus and a selenazole nucleus,
A hydantoinylidene-hydantoin nucleus having 4 substituents, a hydantoinylidene-thiohydantoin nucleus having 4 substituents, and a hydantoinylidene-selenohydantoin nucleus having 4 substituents A heat-developable photoreceptor, wherein the photosensitive layer contains a merocyanine dye having a structure in which any one of them is linked by a linking group having a methine chain. 7. The photothermographic material according to claim 6, wherein the oxazole nucleus is an aromatic oxazole nucleus. 8. The photothermographic material according to claim 7, wherein the aromatic oxazole nucleus is a benzoxazole nucleus. 9. The photothermographic photoreceptor according to claim 6, wherein the thiazole nucleus is an aromatic thiazole nucleus. 10. The photothermographic material according to claim 9, wherein the aromatic thiazole nucleus is a benzothiazole nucleus. 11. The photothermographic material according to claim 6, wherein the selenazole nucleus is an aromatic selenazole nucleus. 12. The photothermographic material according to claim 11, wherein the aromatic selenazole nucleus is a benzoselenazole nucleus. 13. A heat-developable photoreceptor having, on a support, a photosensitive layer containing at least an organic silver salt, a reducing agent, and a photosensitive silver halide or a photosensitive silver halide forming agent. In, a merocyanine having a structure having either an oxazole nucleus or a thiazole nucleus at both ends, and having one nucleus selected from an oxazolidone nucleus, a thiazolidone nucleus and a dihydroimidazolidone nucleus between the both ends. A heat-developable photoconductor characterized by containing a dye in the photosensitive layer. 14. The photothermographic material according to claim 13, wherein the oxazole nucleus is an aromatic oxazole nucleus. 15. The photothermographic material according to claim 14, wherein the aromatic oxazole nucleus is one of a benzoxazole nucleus and a naphthoxazole nucleus. 16. The photothermographic material according to claim 13, wherein the thiazole nucleus is an aromatic thiazole nucleus. 17. The photothermographic material according to claim 16, wherein the aromatic thiazole nucleus is one of a benzothiazole nucleus and a naphthothiazole nucleus. 18. The photothermographic material according to claim 13, wherein the linking group for linking the nuclei has a methine chain. 19. The photosensitive layer is represented by the following general formula (IV):
14. The method according to claim 1, which contains a cyanine dye.
Heat developable photoreceptor. [Chemical 1](In the general formula (IV), r⁴¹, R⁴², R⁴³, R⁴⁴, R⁴⁷,
r⁴⁸, R⁴⁹, R⁵⁰Are each independently a hydrogen atom or a halogen atom.
Child, alkyl group, alkoxy group, aryl group or amino group
R group⁴¹And r⁴², R⁴²And r⁴³, R⁴³And r⁴⁴,
r⁴⁷And r⁴⁸, R ⁴⁸And r⁴⁹, R⁴⁹And r⁵⁰One of
And may form a ring. r⁵¹, R ⁵², R⁵³,
r⁵⁴, R⁵⁵Are each independently a hydrogen atom, an alkyl group or
An aryl group, r⁵¹And r⁵³, R⁵²And r⁵⁴, R⁵³And r
⁵⁵May combine with each other to form a ring. r ⁴⁵And r⁴⁶Is each
Independently, it is an alkyl group or an aralkyl group. Y³Oh
And Y^FourIs an oxygen atom, a sulfur atom, a carbon atom or nitrogen
Atomic, hydrogen in the case of carbon or nitrogen
Any of atom, alkyl group, aryl group, aralkyl group
Are connected. A₂ ^-Is an anion. m^Four, N^FourIs
0, 1 or 2. ) 20. An image forming method comprising forming an image by subjecting the heat-developable photoconductor according to claim 1, 6 or 13 to image exposure and heating. 21. The image forming method according to claim 20, wherein the image exposure is performed by one of a semiconductor laser and an LED.