JP4412300B2 - SQUARYLIUM COMPOUND, HEAT PHOTOGRAPHIC PHOTOSENSITIVE MATERIAL CONTAINING THE COMPOUND AND IMAGE FORMING METHOD - Google Patents

Description

  The present invention relates to a novel squarylium compound, and more particularly to a photothermographic material containing the compound and an image forming method thereof.

  Dyes are used in the field of polymer materials, such as colorants, dichroic dyes for liquid crystals, and semiconductor lasers such as electrophotographic photosensitive materials for electrophotographic printers, recording materials for optical disks, non-linear optical materials, near infrared cut filter materials, etc. Used in the field. Dyes used for these, particularly infrared dyes, have low stability to light or heat, and further improvements are desired.

  On the other hand, in the medical and printing plate making fields, antihalation (AH) dyes and antiirradiation (AI) dyes have been widely used to prevent deterioration of sharpness due to reflection and refraction of light incident upon exposure. In particular, the properties required for AH dyes and AI dyes used in heat-developable photographic light-sensitive materials are sufficient absorption of light of a desired wavelength, no adverse effect on silver halide emulsions, and materials after development processing. For example, not leaving any contamination.

However, few infrared dyes have an absorption maximum in the near infrared, particularly 700 nm to 900 nm, and have very little visible side absorption, and reported examples include, for example, squarylium dyes (for example, Patent Documents 1 and 2). When the dyes described in these are used in a heat-developable photographic light-sensitive material, the thermal stability in the light-sensitive material is not satisfactory, and further improvement has been demanded.
JP 58-2220143 (Claims) US Pat. No. 6,482,950 (Claims)

  An object of the present invention is to provide a photothermographic material which improves the above-mentioned problems of the conventional invention and has excellent storage stability at high temperature and high humidity.

  The above object of the present invention can be achieved by the following configuration.

1. In a photothermographic material having at least one photosensitive layer containing photosensitive silver halide on a support, at least one of the compounds represented by the following general formula ( 2 ) is provided on at least one or both of the support. A photothermographic material comprising a seed-containing layer.

(In the formula, R ₁₁ and R ₁₂ each independently represent a hydrogen atom or a substituent. Z ₁₁ represents O, S, N—R ₁ , Se or Te, and R ₁ represents an alkyl group or an aryl group. Q ₁₁ represents a 6-membered heterocyclic ring, A ₂₁ and B ₂₁ represent an aryl group, provided that A ₂₁ and B ₂₁ are not the same aryl group .

2 . 2. The photothermographic material according to 1, wherein the compound represented by the general formula (2) is a compound represented by the following general formula (5).

_(Wherein, R _{11, R 12} and _{Z 11 are, .Z 12 R} 11, the same meaning as _{R 12} and _{Z 11} in the general formula (2) _{is, O, S, N-R} 2, Se or Te the stands, _{R 2} represents an alkyl group or an aryl group. _{a 21} and _{B 21} have the same meanings as _{a 21} and _{B 21} in the general formula (2).)
3 . Before the title compound which is represented by a general formula (5) is, heat-developable photographic material according to the 1 or 2, characterized in that a compound represented by the following general formula (6).

_{(Wherein, R 11} and _{R 12, .A 21} and _{B 21} have the same meanings as _{R 11} and _{R 12} in the general formula (2) is synonymous with _{A 21} and _{B 21} in the general formula (2) is there.)
4. 4. An image forming method comprising: exposing the photothermographic material according to any one of 1 to 3 above to 80 ° C. to 150 ° C. after exposure using a laser light source.

（式中、Ｒ _１１ 及びＲ _１２ は、各々独立に水素原子又は置換基を表す。Ａ _２１ 及びＢ _２１ は、アリール基を表す。但し、Ａ _２１ 及びＢ _２１ が互いに同一のアリール基であることはない。） 5 . Squarylium compound, characterized by being represented by the following general formula (6).

(It _{wherein, R 11} and _{R 12,} is _{.A 21} and _{B 21} each independently represent a hydrogen atom or a substituent, which represents an aryl group. _{However, A 21} and _{B 21} are the same aryl groups from one another No.)

  According to the present invention, a photothermographic material excellent in storage stability can be provided. In particular, it is possible to provide a photothermographic material having good sharpness when stored at high temperature and high humidity.

  The present invention will be described in more detail.

In the general formula ( 2 ), R ₁₁ and R ₁₂ each independently represent a hydrogen atom or a substituent. Examples of the substituent represented by R ₁₁ and R ₁₂ include an alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl group, an aryl group, a heterocyclic group, a halogen atom, and a cyano group. A hydrogen atom, an alkyl group or an aryl group is preferable, and a hydrogen atom or an alkyl group is more preferable.

Z ₁₁ represents O, S, N—R ₁ , Se or Te, and R ₁ represents an alkyl group or an aryl group. O, S, or N—R ₁ is preferable, and O or S is more preferable.

Q ₁₁ represents a 6-membered heterocyclic ring, and examples of the heterocyclic ring include pyrylium, thiopyrylium, selenopyrylium, ternopyrylium, pyridinium, benzpyrylium, benzthiopyrylium, benzselenopyrylium, Pyrylium, thiopyrylium or selenopyrylium, more preferably pyrylium or thiopyrylium. These heterocyclic rings may have a substituent. Examples of the substituent include an alkyl group, a cycloalkyl group, a halogenated alkyl group, an alkenyl group, an alkynyl group, an aryl group, a heterocyclic group, a halogen atom, and a cyano group. Group, hydroxyl group, carboxyl group, alkoxy group, aryloxy group, silyloxy group, heterocyclic oxy group, acyloxy group, carbamoyloxy group, alkoxycarbonyloxy group, aryloxycarbonyloxy group, amino group, anilino group, acylamino group, Aminocarbonylamino group, alkoxycarbonylamino group, aryloxycarbonylamino group, sulfamoylamino group, alkyl and arylsulfonylamino group, mercapto group, alkylthio group, arylthio group, heterocyclic thio group, sulfamoyl group, sulfo , Alkyl and arylsulfinyl groups, alkyl and arylsulfonyl groups, acyl groups, aryloxycarbonyl groups, alkoxycarbonyl groups, carbamoyl groups, aryl and heterocyclic azo groups, imide groups, silyl groups, hydrazino groups, ureido groups, boronic acid groups , Phosphato groups, sulfato groups, and other known substituents.

A ₂₁ and B ₂₁ represent an aryl group. These aryl groups may have a substituent. Examples of the substituent include an alkyl group, a cycloalkyl group, a halogenated alkyl group, an alkenyl group, an alkynyl group, an aryl group, a heterocyclic group, a halogen atom, and a cyano group. , Hydroxyl group, carboxyl group, alkoxy group, aryloxy group, silyloxy group, heterocyclic oxy group, acyloxy group, carbamoyloxy group, alkoxycarbonyloxy group, aryloxycarbonyloxy group, amino group, anilino group, acylamino group, amino Carbonylamino, alkoxycarbonylamino, aryloxycarbonylamino, sulfamoylamino, alkyl and arylsulfonylamino, mercapto, alkylthio, arylthio, heterocyclic thio, sulfamoyl, sulfamoyl Groups, alkyl and arylsulfinyl groups, alkyl and arylsulfonyl groups, acyl groups, aryloxycarbonyl groups, alkoxycarbonyl groups, carbamoyl groups, aryl and heterocyclic azo groups, imide groups, silyl groups, hydrazino groups, ureido groups, boronic acids Group, phosphato group, sulfato group, and other known substituents. Preferably, an alkyl group, a cycloalkyl group, a halogenated alkyl group, an aryl group, a heterocyclic group, a halogen atom, a cyano group, an alkoxy group, an aryloxy group, and more preferably an alkyl group, an aryl group, a halogen atom, An alkoxy group; However, A ₂₁ and B ₂₁ are not the same aryl group.

In the general formula _(5), R _{11, R 12} and _{Z 11} have the same meaning as _{R 11, R 12} and _{Z 11} in the general formula (2). Z ₁₂ represents O, S, N—R ₂ , Se or Te, and R ₂ represents an alkyl group or an aryl group. A ₂₁ and _{B 21} have the same meanings as _{A 21} and _{B 21} in the general formula (2).
In the general formula _{(6), R 11} and _{R 12} is the same as defined in the _{R 11} and _{R 12} in the general formula (2). A ₂₁ and _{B 21} have the same meanings as _{A 21} and _{B 21} in the general formula (2).

Although the specific example of a compound represented by General formula ( 2 ), General formula (5), and General formula (6) below is shown, this invention is not limited to these.

  The above exemplified compounds can be easily prepared by the methods described in Dies & Pigments September 1988, pages 85 to 107, JP-A-10-036695, JP-A-10-158253, JP-A-2001-117201, JP-A-2001-011070, and the like. Can be synthesized. As a synthesis example, a part of the synthesis method of the compounds represented by the general formulas (1) to (6) is shown below.

  (Synthesis route of exemplary compound sq-38)

Synthesis of Intermediate A 50 ml of ethylene glycol dimethyl ether was added to 16.0 g of sodium hydride and heated to 50 ° C. A solution prepared by mixing 27.6 g of p-fluoroacetophenone and 35.2 g of ethyl acetate was added dropwise to the reaction solution, followed by stirring for 5 hours while maintaining the temperature at 50 ° C. After cooling the reaction solution with ice water, 30 ml of methanol and 150 ml of ice water were sequentially added. 30 ml of concentrated hydrochloric acid was added, extraction was performed with 200 ml of ethyl acetate, and the extract was dried over sodium sulfate. After filtration under reduced pressure, the solvent was removed by concentration under reduced pressure. The residue was purified by silica gel column chromatography to obtain 17.1 g of intermediate A.

Synthesis of Intermediate B 19.0 g of sodium hydride and 200 ml of ethylene glycol dimethyl ether were mixed and heated to reflux.

  Under heating under reflux, a solution prepared by mixing 17.1 g of Intermediate A, 28.0 g of methyl 3,5-dimethoxybenzoate and 200 ml of ethylene glycol dimethyl ether was added dropwise over 30 minutes. After completion of the dropwise addition, the mixture was refluxed with heating for 4 hours, and then 350 ml of ethylene glycol dimethyl ether was distilled off. After cooling to room temperature, it was cooled with water and 30 ml of methanol was slowly added. The reaction solution was cooled with ice water, and 1 L of water and 40 ml of concentrated hydrochloric acid were further added. Extraction was performed with 150 ml of ethyl acetate, and the extract was dried over sodium sulfate. After filtration under reduced pressure, the solvent was removed by concentration under reduced pressure. The residue was purified by silica gel column chromatography to obtain 21.3 g of Intermediate B.

Synthesis of Intermediate C 200 ml of concentrated sulfuric acid was cooled with ice water, and Intermediate B was added to concentrated sulfuric acid. The mixture was stirred for 2 hours under cooling with ice water. The reaction solution was added dropwise to 2 L of ice-cooled water, and the precipitated crystals were collected by filtration and washed with water. By recrystallization from ethyl acetate-hexane, 16.1 g of Intermediate C was obtained.

Synthesis of Intermediate D In a nitrogen atmosphere, 5.0 g of Intermediate C was dissolved in 400 ml of tetrahydrofuran. The reaction solution was heated to 50 ° C., and 27.4 ml of methylmagnesium bromide (0.84 M tetrahydrofuran solution) was added dropwise, followed by stirring for 2 hours. The reaction solution was cooled with ice water, 100 ml of saturated aqueous ammonium bromide solution was added, and extraction was performed with 150 ml of ethyl acetate. The extract was dried over sodium sulfate, filtered under reduced pressure, and concentrated under reduced pressure to obtain 6.2 g of Intermediate D.

Synthesis of Exemplary Compound sq-38 Intermediate D was dissolved in 60 ml of n-propanol. 870 mg of squaric acid was added and stirred at 80 ° C. for 1.5 hours. After allowing to cool to room temperature, the precipitated crystals were collected by filtration and washed with 20 ml of n-propanol. The obtained crystal was purified by silica gel column chromatography to obtain 2.2 g of exemplary compound sq-38. λmax = 817 nm (in 2-butanone)
The structure of the obtained compound was confirmed by NMR spectrum and mass spectrum.

The compounds represented by the general formula ( 2 ), the general formula (5) and the general formula (6) may be added to any layer of the photothermographic material. a filter layer formed on the opposite sides of the supporting bearing member of the non-photosensitive layer or the photosensitive layer, more preferably formed on opposite sides of the support of the light-sensitive layer and the photosensitive layer of the photosensitive layer side It is included in the filter layer. The amount of the compound represented by the general formula ( 2 ) , the general formula (5), or the general formula (6) is preferably 1 × 10 ⁻⁵ to 10 mmol with respect to 1 square meter, and 1 × 10 ⁻⁴ to 1 More preferred is mmol, and most preferred is 1 × 10 ⁻³ to 1 × 10 ⁻¹ mmol.

The compounds represented by the general formula ( 2 ) , the general formula (5) and the general formula (6) can be added according to a known method. That is, it can be dissolved in an alcohol such as methanol or ethanol, a ketone such as methyl ethyl ketone or acetone, or a polar solvent such as dimethyl sulfoxide or dimethylformamide, and added to the coating solution. Further, fine particles of 1 μm or less can be dispersed and added in water or an organic solvent. Many techniques for fine particle dispersion are disclosed, but they can be dispersed according to these techniques.

  Next, the photothermographic material of the present invention will be described. The photosensitive layer of the photothermographic material of the present invention preferably contains an organic silver salt and a reducing agent in addition to the photosensitive silver halide.

  The organic silver salt that can be used in the present invention is a reducible silver source, and is an organic acid containing a reducible silver ion source. Examples of the organic acid used in the present invention include aliphatic carboxylic acid, carbocyclic carboxylic acid, heterocyclic carboxylic acid, heterocyclic compound and the like, but particularly long chain (10-30, preferably 15-25). The aliphatic carboxylic acid having the number of carbon atoms) and the heterocyclic carboxylic acid having a nitrogen-containing heterocyclic ring are preferably used. An organic silver salt complex having a total stability constant with respect to silver ions having a ligand of 4.0 to 10.0 is also useful.

  Examples of such organic acid silver salts are described in Research Disclosure (hereinafter abbreviated as RD) 17029 and 29963. Of these, silver salts of fatty acids are preferably used, and silver behenate, silver arachidate, and silver stearate are particularly preferably used.

  The organic silver salt compound described above can be obtained by mixing a water-soluble silver compound and a compound that forms a complex with silver, and a normal mixing method, a back mixing method, a simultaneous mixing method, and the like are preferably used. It is also possible to use a controlled double jet method as described in JP-A-9-127643.

  In the present invention, the organic silver salt preferably has an average particle size of 1 μm or less and is monodispersed. The average particle diameter of the organic silver salt refers to a diameter when a sphere equivalent to the volume of the organic silver salt particle is considered when the organic silver salt particle is, for example, a spherical or rod-like particle. In the case of tabular grains, it means the diameter when converted into a circular image having the same area as the projected area of the main surface. The average particle size is preferably 0.01 to 0.8 μm, particularly preferably 0.05 to 0.5 μm. Moreover, monodispersion is synonymous with the case of the below-mentioned silver halide, Preferably monodispersion degree is 1 to 30%. In the present invention, the organic silver salt is more preferably monodisperse particles having an average particle diameter of 1 μm or less, and an image having a high density can be obtained by setting the content within this range. Further, the organic silver salt preferably has tabular grains of 60% by number or more of the total organic silver. In the present invention, the tabular grains mean those having an average grain diameter / thickness ratio, that is, an aspect ratio (abbreviated as AR) represented by the following formula of 3 or more.

AR = average particle diameter (μm) / thickness (μm)
Such organic silver particles are preferably preliminarily dispersed together with a binder, a surfactant or the like, if necessary, and then dispersed and ground with a media disperser or a high-pressure homogenizer. As the disperser that can be used in the preliminary dispersion, for example, a general stirrer such as an anchor type or a propeller type, a high-speed rotating centrifugal radiation stirrer (dissolver), or a high-speed rotating shear stirrer (homomixer) may be used. it can. Examples of the media disperser include a rolling mill such as a ball mill, a planetary ball mill, and a vibration ball mill, a bead mill that is a medium agitation mill, an attritor, and other basket mills, and a high-pressure homogenizer. For example, various types such as a type that collides with a wall, a plug, etc., a type that allows liquids to collide with each other at high speed after dividing the liquid, and a type that allows a thin orifice to pass through can be used.

  In the apparatus used when dispersing the organic silver particles used in the present invention, for example, ceramics such as zirconia, alumina, silicon nitride, boron nitride, or diamond is used as the material of the member in contact with the organic silver particles. It is preferable to use zirconia, in particular.

  The organic silver particles used in the present invention preferably contain 0.01 to 0.5 mg of Zr per 1 g of silver, particularly preferably 0.01 to 0.3 mg of Zr. When carrying out the above dispersion, optimizing the binder concentration, the preliminary dispersion method, the dispersing machine operating conditions, the number of times of dispersion, etc. is very preferable as a method for obtaining the organic silver salt particles used in the present invention.

  The photosensitive silver halide according to the present invention preferably has a smaller average grain size, and preferably has an average grain size of 0.1 μm or less, more preferably, in order to suppress white turbidity after image formation and to obtain good image quality. 0.01-0.1 micrometer, especially 0.02-0.08 micrometer are preferable. The particle size here refers to the diameter (equivalent circle diameter) of a circle having the same area as each particle image observed with an electron microscope. The silver halide is preferably monodispersed. The monodispersion here means that the monodispersity obtained by the following formula is 40% or less. The particles are more preferably 30% or less, and particularly preferably 20% or less.

Monodispersity = (standard deviation of particle size) / (average particle size value) × 100
The shape of the photosensitive silver halide grains is not particularly limited, but the ratio occupied by the Miller index [100] plane is preferably high, and this ratio is 50% or more, further 70% or more, particularly 80% or more. Preferably there is. The ratio of the Miller index [100] plane is calculated by using the adsorption dependency between the [111] plane and the [100] plane in the adsorption of the sensitizing dye. Tani, J .; Imaging Sci. 29, 165 (1985).

  In the present invention, another preferred shape of the photosensitive silver halide is a tabular grain. The term “tabular grain” as used herein refers to those having an aspect ratio (r / h) of 3 or more when the square root of the projected area is the grain size r μm and the thickness in the vertical direction is h μm. Among them, the aspect ratio is preferably 3 to 50. Moreover, it is preferable that the particle size of a tabular grain is 0.1 micrometer or less, Furthermore, 0.01 micrometer-0.08 micrometer are preferable. These tabular grains are described in US Pat. Nos. 5,264,337, 5,314,798, 5,320,958, etc., and the desired tabular grains can be easily obtained. it can.

  The photosensitive halogen composition is not particularly limited, and may be any of silver chloride, silver chlorobromide, silver chloroiodobromide, silver bromide, silver iodobromide, and silver iodide. The emulsion used in the present invention is P.I. Chifie et Physique Photographic (published by Paul Montel, 1967) by Glafkides. F. Duffin's Photographic Emission Chemistry (published by The Focal Press, 1966), V.C. L. It can be prepared based on the method described in Making and Coating Photographic Emulsion (published by The Focal Press, 1964) by Zelikman et al.

  The photosensitive silver halide according to the present invention preferably contains a metal ion belonging to Groups 6 to 11 of the periodic table. As the metal, W, Fe, Co, Ni, Cu, Ru, Rh, Pd, Re, Os, Ir, Pt, and Au are preferable.

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

General formula [ML ₆ ] ^m
In the formula, M represents a transition metal selected from Group 6 to 11 elements of the periodic table, L represents a ligand, and m represents 0,-, 2-, 3-, or 4-. Specific examples of the ligand represented by L include, for example, halides (fluorides, chlorides, bromides and iodides), cyanides, cyanates, thiocyanates, selenocyanates, tellurocyanates, azides and acos. Each ligand includes nitrosyl, thionitrosyl, and the like, preferably aco, nitrosyl, thionitrosyl, and the like. When an acoligand is present, it preferably occupies one or two of the ligands. L may be the same or different.

M is preferably rhodium (Rh), ruthenium (Ru), rhenium (Re), iridium (Ir) and osmium (Os). Specific examples of transition metal complex ions containing these include [RhCl ₆ ] ^-3 [RhCl ₅ (H ₂ O)] ⁻² , [RhBr ₅ (NO)] ⁻² , [RhCl ₅ (NS)] ⁻² , [RhCl ₄ (NO) (CN)] ⁻¹ , [RhCl (NO) ) (CN) ₄ ] ⁻² , [ReCl ₆ ] ⁻³ , [ReBr ₆ ] ⁻³ , [ReCl ₅ (NO)] ⁻² , [Re (NS) Br ₃ ] ⁻² , [Re (NO) ( CN) _5] ^-2, [RuCl _6] ^-3, [RuCl ₄ (H ₂ O) _2] ^-1, [RuCl ₅ (NO)] ^-2, [RuBr ₅ (NS)] ^-2, [RuCl ₅ (NS)] ^-2, [OsCl _6] ^-3, [OsCl ₅ (NO)] ^-2, [Os (NO) (CN) _5] ^-2, [ Os (NO) (CN)] ⁻¹ , [Os (NS) Br ₅ ] ⁻² , [IrCl ₆ ] ⁻³ , [IrCl ₅ (H ₂ O)] ⁻² , [IrBr ₅ (NO)] ⁻² , [IrCl ₅ (NS)] ^{-2 and the} like.

One kind of metal ion, metal complex or metal complex ion described above may be used, or two or more kinds of the same kind of metal and different kinds of metals may be used in combination. The content of these metal ions, metal complexes or metal complex ions, generally is suitably 1 × 10 ^-9 ~1 × 10 ^-2 mol per mol of silver halide, preferably 1 × 10 ^{- 8} to 1 × 10 ⁻⁴ mol.

  These metal-providing compounds are preferably added at the time of silver halide grain formation and incorporated into the silver halide grains. Preparation of silver halide grains, that is, nucleation, growth, physical ripening, chemical sensitization It may be added at any stage before or after, but is preferably added at the stage of nucleation, growth and physical ripening, more preferably at the stage of nucleation and growth, most preferably Add at the stage of formation.

  In addition, it may be divided and added several times, or it can be uniformly contained in the silver halide grains. JP-A-63-29603, JP-A-2-306236, 3 As described in No. 167545, No. 4-76534, No. 6-110146, No. 5-273683, etc., it can also be contained with distribution in the particles. Preferably, a distribution can be provided inside the particles. These metal compounds can be added by dissolving in water or an appropriate organic solvent (for example, alcohols, ethers, glycols, ketones, esters, amides). A method of adding an aqueous solution or a metal compound and an aqueous solution in which NaCl and KCl are dissolved together to a water-soluble silver salt solution or a water-soluble halide solution during particle formation, or a silver salt solution and a halide solution are simultaneously mixed. When adding a third aqueous solution, a method of preparing silver halide grains by a three-liquid simultaneous mixing method, a method of adding an aqueous solution of a required amount of a metal compound to the reaction vessel during grain formation, or silver halide There is a method of adding another silver halide grain previously doped with a metal ion or complex ion at the time of preparation and dissolving it. In particular, a method of adding an aqueous solution of a metal compound powder or an aqueous solution in which a metal compound and NaCl, KCl are dissolved together is added to the water-soluble halide solution.

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

  In the present invention, the photosensitive silver halide grains may or may not be desalted after grain formation. However, when desalting is performed, for example, the noodle method, the flocculation method, etc. are known in the art. Can be washed with water and desalted.

  The silver halide grains used in the present invention are preferably chemically sensitized. As a preferable chemical sensitization method, a sulfur sensitization method, a selenium sensitization method, a tellurium sensitization method and the like well known in the art can be used. Further, noble metal sensitization methods such as gold compounds, platinum, palladium, iridium compounds, and reduction sensitization methods can be used.

  As the compound preferably used in the above-described sulfur sensitization method, selenium sensitization method, and tellurium sensitization method, known compounds can be used. For example, compounds described in JP-A-7-128768 are used. be able to. Examples of tellurium sensitizers include diacyl tellurides, bis (oxycarbonyl) tellurides, bis (carbamoyl) tellurides, diacyl tellurides, bis (oxycarbonyl) ditellurides, bis (carbamoyl) ditellurides, P = Compound having Te bond, tellurocarboxylates, Te-organyl tellurocarboxylates, di (poly) tellurides, tellurides, tellurols, telluroacetals, tellurosulfonates, compounds having P-Te bond Te-containing heterocycles, tellurocarbonyl compounds, inorganic tellurium compounds, colloidal tellurium, and the like can be used.

  Examples of the compound preferably used for the noble metal sensitization include, for example, chloroauric acid, potassium chloroaurate, potassium aurithiocyanate, gold sulfide, gold selenide, U.S. Pat. No. 2,448,060 and British Patent 618,061. The compounds described in No. etc. can be preferably used.

  As compounds used in the reduction sensitization method, for example, in addition to ascorbic acid and thiourea dioxide, for example, stannous chloride, aminoiminomethanesulfinic acid, hydrazine derivatives, borane compounds, silane compounds, polyamine compounds, etc. are used. Can do. Further, reduction sensitization can be performed by ripening the silver halide emulsion while maintaining the pH at 7 or higher or the pAg at 8.3 or lower. Further, reduction sensitization can be performed by introducing a single addition portion of silver ions during grain formation.

  Examples of the reducing agent used in the photothermographic material of the present invention include generally known reducing agents such as phenols, polyphenols having two or more phenol groups, naphthols, bisnaphthols, 2 Polyhydroxybenzenes having two or more hydroxyl groups, Polyhydroxynaphthalenes having two or more hydroxyl groups, Ascorbic acids, 3-pyrazolidones, pyrazolin-5-ones, pyrazolines, phenylenediamines, hydroxylamines, hydroquinone Monoethers, hydroxamic acids, hydrazides, amide oximes, N-hydroxyureas, and the like, and more specifically, for example, U.S. Pat. Nos. 3,615,533, 3,679,426, 3,672,904, 3,751,252, 3, 82,949, 3,801,321, 3,794,488, 3,893,863, 3,887,376, 3,770,448, 3,819,382, 3,773,512, 3,839,048, 3,887,378, 4,009,039, 4,021 240, British Patent No. 1,486,148, Belgian Patent No. 786,086, Japanese Patent Laid-Open Nos. 50-36143, 50-36110, 50-116023, 50-99719, 50 -140113, 51-51933, 51-23721, 52-84727, and JP-B-51-35851, the reducing agents and the like can be mentioned. Select from appropriate reducing agents It can be used Te. As the selection method, the most efficient method is to confirm the suitability of the reducing agent by actually producing a photothermographic material containing a reducing agent and directly evaluating its photographic performance.

  Among the reducing agents described above, preferred reducing agents when using an aliphatic carboxylic acid silver salt as the organic silver salt include polyphenols in which two or more phenol groups are linked by an alkylene group or sulfur, particularly a phenol group. Phenol in which an alkyl group (for example, a methyl group, an ethyl group, a propyl group, a t-butyl group, a cyclohexyl group, or the like) or an acyl group (for example, an acetyl group, a propionyl group, or the like) is substituted on at least one position adjacent to the hydroxy substitution position Polyphenols in which two or more of the groups are linked by an alkylene group or sulfur, such as 1,1-bis (2-hydroxy-3,5-dimethylphenyl) -3,5,5-trimethylhexane, 1,1-bis (2-hydroxy-3-tert-butyl-5-methylphenyl) methane, 1,1-bis (2-hydroxy-3) 5-di-t-butylphenyl) methane, (2-hydroxy-3-t-butyl-5-methylphenyl)-(2-hydroxy-5-methylphenyl) methane, 6,6′-benzylidene-bis (2 , 4-di-tert-butylphenol), 6,6′-benzylidene-bis (2-tert-butyl-4-methylphenol), 6,6′-benzylidene-bis (2,4-dimethylphenol), 1, 1-bis (2-hydroxy-3,5-dimethylphenyl) -2-methylpropane, 1,1,5,5-tetrakis (2-hydroxy-3,5-dimethylphenyl) -2,4-ethylpentane, US Pat. Nos. 3,5 such as 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane and 2,2-bis (4-hydroxy-3,5-di-t-butylphenyl) propane No. 9,903, No. 4,021,249, British Patent No. 1,486,148, JP-A Nos. 51-51933, No. 50-36110, No. 50-11623, No. 52-84727, Polyphenol compounds described in JP-B-51-35727, bisnaphthols described in US Pat. No. 3,672,904, for example, 2,2′-dihydroxy-1,1′-binaphthyl, 6,6 ′ -Dibromo-2,2'-dihydroxy-1,1'-binaphthyl, 6,6'-dinitro-2,2'-dihydroxy-1,1'-binaphthyl, bis (2-hydroxy-1-naphthyl) methane, 4,4'-dimethoxy-1,1'-dihydroxy-2,2'-binaphthyl and the like, as well as sulfonamidophenols as described in U.S. Pat. No. 3,801,321. Are sulfonamido naphthols such as 4-benzenesulfonamidophenol, 2-benzenesulfonamidophenol, 2,6-dichloro-4-benzenesulfonamidophenol, 4-benzenesulfonamidonaphthol, JP 2003-302723, Examples thereof include polyphenol compounds described in JP-A No. 2003-315954 and JP-A No. 2004-4650. Particularly preferred are polyphenol compounds described in JP-A Nos. 2003-302723, 2003-315594, and 2004-4650.

  The appropriate amount of the reducing agent used in the photothermographic material of the present invention is not uniform depending on the type of organic silver salt used, the type of reducing agent, and other additives, but in general, per mole of organic silver salt. A range of 0.05 to 10 mol, preferably 0.1 to 3 mol is appropriate. Within this range, two or more reducing agents described above may be used in combination. In the present invention, it is preferable to add and apply the reducing agent to the photosensitive layer coating solution immediately before coating in order to reduce the photographic performance fluctuation due to the stagnation time of the photosensitive layer coating solution.

  Next, preferred components excluding the above-described items of the photothermographic material of the present invention will be described.

  The photothermographic material of the present invention is obtained by laminating a photosensitive layer and a protective layer containing the above-mentioned organic silver salt, photosensitive silver halide, and reducing agent on a support in this order. Accordingly, an intermediate layer is preferably provided between the support and the photosensitive layer.

  Further, a photothermographic material having a backing layer provided on the surface opposite to the photosensitive layer to ensure transportability and prevent blocking with the protective layer can also be suitably used. Each layer may be a single layer, or may be composed of two or more layers having the same or different composition.

  In the present invention, a binder resin is preferably used to form each of the above layers. As such a binder resin, a conventionally used transparent or translucent binder resin can be selected and used as appropriate. Examples of such a binder resin include polyvinyl formal, polyvinyl acetoacetal, and polyvinyl butyral. Polyvinyl acetal resins such as ethyl cellulose, hydroxyethyl cellulose, cellulose resins such as cellulose acetate butyrate, styrene resins such as polystyrene, styrene-acrylonitrile copolymers, styrene-acrylonitrile-acrylic rubber copolymers, polyvinyl chloride, chlorine Vinyl chloride-based resins such as modified polypropylene, polyester, polyurethane, polycarbonate, polyarylate, epoxy resin, acrylic resin, and the like. These may be used alone or in combination of two or more. It may be used in combination with fat.

  In addition, the said binder resin can be suitably selected and used for each layer of a protective layer, an intermediate | middle layer, or the backcoat layer provided when needed, unless the objective of this invention is impaired. In addition, you may use an epoxy resin, an acrylic monomer, etc. which can be hardened | cured with an active energy ray as a layer formation binder resin for an intermediate | middle layer and a backcoat layer. In the present invention, the following aqueous binder resins are also preferably used.

  As a preferable resin, a water-soluble polymer or a water-dispersible hydrophobic polymer (latex) can be used. For example, polyvinylidene chloride, vinylidene chloride-acrylic acid copolymer, vinylidene chloride-itaconic acid copolymer, sodium polyacrylate, polyethylene oxide, acrylic acid amide-acrylic acid ester copolymer, styrene-maleic anhydride copolymer Examples thereof include acrylonitrile-butadiene copolymer, vinyl chloride-acetic acid part nyl copolymer, and styrene-butadiene-acrylic acid copolymer. These constitute an aqueous coating solution, but form a uniform resin film at the stage of drying after coating and forming a coating film. When these are used, an organic silver salt, silver halide, reducing agent, etc. as an aqueous dispersion, mixed with these latexes to form a uniform dispersion, and then applied to form a photothermographic layer. Can be formed. By drying, the latex coalesces and forms a uniform film. Further, a polymer having a glass transition point of −20 ° C. to 80 ° C. is preferable, and −5 ° C. to 60 ° C. is particularly preferable. This is because if the glass transition point is high, the temperature at which heat development is performed becomes high, and if it is low, fogging is likely to occur, resulting in a decrease in sensitivity and softening. The water-dispersed polymer is preferably dispersed in the form of fine particles having an average particle diameter in the range of 1 nm to several μm. The water-dispersed hydrophobic polymer is called a latex, and is preferably a latex that improves water resistance among widely used binders for aqueous coating. The amount of latex used for the purpose of obtaining water resistance as a binder is determined in consideration of applicability, but is preferably as large as possible from the viewpoint of moisture resistance. The ratio of latex to the total binder mass is preferably 50 to 100%, particularly preferably 80 to 100%.

In the present invention, as these binder resins, the amount of solids is 0.25 to 10 times the amount of silver attached, for example, when the amount of silver attached is 2.0 g / m ² , the amount of polymer attached is It is preferable that it is 0.5-20 g / m < ² >. Further, more preferably 0.5 to 7 times the grain-weight, for example, the amount with silver, if 2.0 g / m ^2, a 1.0~14g / m ^2. If the amount of binder resin is less than 0.25 times the amount of silver, the silver color tone may be significantly deteriorated and may not endure use, and if the amount is more than 10 times the amount of silver, it may become soft and endure use. is there.

  Further, the image forming layer according to the present invention includes, in addition to the above-described essential components and binder resin, an antifoggant, a toning agent, a sensitizing dye, and a substance that exhibits supersensitization (supersensitization). Various additives may also be added.

In the present invention, examples of the antifogging agent include compounds disclosed in US Pat. Nos. 3,874,946 and 4,756,999, —C (X ₁ ) (X ₂ ) ( X ₃ ) (wherein X ₁ and X ₂ represent a halogen atom, and X ₃ represents hydrogen or a halogen atom), a heterocyclic compound having one or more substituents, JP-A-9-288328, No. 9-90550, US Pat. No. 5,028,523 and European Patent Nos. 600,587, 605,981, 631,176, etc. be able to.

  Examples of toning agents added for the purpose of improving the silver tone after development include imides (for example, phthalimide); cyclic imides, pyrazolin-5-ones, and quinazolinones (for example, succinimide, 3-phenyl- 2-pyrazolin-5-one, 1-phenylurazole, quinazoline and 2,4-thiazolidinedione); naphthalimides (eg N-hydroxy-1,8-naphthalimide); cobalt complexes (eg cobalt hexamine trifluoro) Acetate), mercaptans (eg, 3-mercapto-1,2,4-triazole); N- (aminomethyl) aryl dicarboximides (eg, N- (dimethylaminomethyl) phthalimide); blocked pyrazoles , Isothiuronium ) Derivatives and certain photobleaching agents (eg, N, N′-hexamethylene (1-carbamoyl-3,5-dimethylpyrazole), 1,8- (3,6-dioxaoctane) bis (isothione) A combination of uronium trifluoroacetate) and 2- (tribromomethylsulfonyl) benzothiazole); a merocyanine dye (for example, 3-ethyl-5-((3-ethyl-2-benzothiazolinylidene (benzothiazolidine) Nylidene))-1-methylethylidene) -2-thio-2,4-oxazolidinedione); phthalazinone, phthalazinone derivatives or metal salts of these derivatives (eg 4- (1-naphthyl) phthalazinone, 6-chlorophthala Dinone, 5,7-dimethyloxyphthalazinone, and 2,3-dihydro-1,4-phthalazinedio ); A combination of phthalazinone and a sulfinic acid derivative (eg 6-chlorophthalazinone + sodium benzenesulfinate or 8-methylphthalazinone + sodium p-trisulfonate); a combination of phthalazine + phthalic acid; phthalazine (phthalazine adduct) And maleic anhydride, and phthalic acid, 2,3-naphthalenedicarboxylic acid or o-phenylene acid derivatives and anhydrides thereof (eg, phthalic acid, 4-methylphthalic acid, 4-nitrophthalic acid and tetrachlorophthalic acid) A combination with at least one compound selected from anhydride); quinazolinediones, benzoxazines, naltoxazine derivatives; benzoxazine-2,4-diones (eg, 1,3-benzoxazine-2,4-dione) Pyrimidines and asymmetric-tria Gins (eg, 2,4-dihydroxypyrimidine) and tetraazapentalene derivatives (eg, 3,6-dimercapto-1,4-diphenyl-1H, 4H-2,3a, 5,6a-tetraazapentalene) And preferred color toning agents are phthalazone and phthalazine. In addition, as long as it is a range which does not inhibit the objective of this invention, you may add a toning agent to the protective layer mentioned later.

  As the sensitizing dye, for example, for an argon ion laser light source, JP-A-60-162247, JP-A-2-48635, US Pat. No. 2,161,331, West German Patent 936,071 Simple merocyanines described in JP-A-5-11389, etc., and trinuclear compounds described in JP-A-50-62425, JP-A-54-18726, and JP-A-59-102229 with respect to a helium neon laser light source. Cyanine dyes, merocyanines described in JP-A-7-287338, Japanese Patent Publication Nos. 48-42172, 51-9609, 55-39818, Thiacarbocyanines described in JP-A-62-284343 and JP-A-2-105135 are not suitable for infrared semiconductor laser light sources. Tricarbocyanines described in JP-A-59-191032 and JP-A-60-80841, and 4-carbon compounds described in general formulas (IIIa) and (IIIb) in JP-A-59-192242 and JP-A-3-67242. Dicarbocyanines and the like containing a quinoline nucleus are advantageously selected. Further, in the case where the wavelength of the infrared laser light source is 750 nm or more, more preferably 800 nm or more, in order to cope with a laser in such a wavelength range, JP-A-4-18239, JP-A-5-341432, JP-B-6 Nos. -52387, 3-10931, U.S. Pat. No. 5,441,866, and JP-A-7-13295 are preferably used.

  Further, examples of supersensitizers include RD 17643, JP-B Nos. 9-25500, 43-4933, JP-A-59-19032, 59-192242, JP-A-5-341432, and the like. In the present invention, a heteroaromatic mercapto compound represented by the following general formula (M), which is a general formula (Ma) that substantially forms the mercapto compound, can be used. The disulfide compounds represented can be used.

General formula (M)
Ar-SM
General formula (Ma)
Ar-SS-Ar
In the general formula (M), M represents a hydrogen atom or an alkali metal atom, and Ar represents a heteroaromatic ring or condensed heteroaromatic ring having one or more nitrogen, sulfur, oxygen, selenium or tellurium atoms. The heteroaromatic ring is preferably benzimidazole, naphthimidazole, benzothiazole, naphthothiazole, benzoxazole, naphthoxazole, benzoselenazole, benzotelrazole, imidazole, oxazole, pyrazole, triazole, triazine, pyrimidine, pyridazine, pyrazine, pyrazine, Pyridine, purine, quinoline or quinazoline. Moreover, in general formula (Ma), Ar is synonymous with the said general formula (M).

  The heteroaromatic ring includes, for example, a halogen atom (for example, Cl, Br, I), a hydroxy group, an amino group, a carboxyl group, and an alkyl group (for example, one or more carbon atoms, preferably 1 to 4 carbon atoms). And a substituent selected from the group consisting of an alkoxy group (for example, one having 1 or more carbon atoms, preferably 1 to 4 carbon atoms).

  The supersensitizer used in the present invention is preferably used in the range of 0.001 to 1.0 mol per mol of silver in the emulsion layer containing the organic silver salt and silver halide grains, and particularly 1 mol of silver. The range is preferably 0.01 to 0.5 mol per unit.

  The image recording layer according to the present invention may contain a macrocyclic compound containing a hetero atom. A 9-membered or larger macrocyclic compound containing at least one of a nitrogen atom, an oxygen atom, a sulfur atom and a selenium atom as a heteroatom is preferred, a 12-24 membered ring is more preferred, and a 15-21 membered ring is still more preferred. is there.

  A typical compound is crown ether, which was synthesized by Pederson in 1967 and has been synthesized many times since its unique report. These compounds are C.I. J. et al. Pederson, Journal of American chemical society vol, 86 (2495), 7017-7036 (1967), G.P. W. Gokel, S.M. H, Korzenowski, “Macrocyclic polyethr synthesis”, Springer-Vergal (1982) and the like.

  In addition to the additives described above, for example, surfactants, antioxidants, stabilizers, plasticizers, ultraviolet absorbers, coating aids and the like may be used in the photosensitive layer according to the present invention. As these additives and the other additives described above, compounds described in RD Item 17029 (June 1978, p. 9-15) are preferably used.

  In the present invention, the photosensitive layer may be a single layer or a plurality of layers having the same or different compositions. The film thickness of the photosensitive layer is usually 10 to 30 μm.

  Next, the support and protective layer, which are essential as the layer structure of the photothermographic material of the present invention, will be described in detail.

  Examples of the support used in the photothermographic material of the present invention include acrylic acid ester, methacrylic acid ester, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polycarbonate, polyarylate, polyvinyl chloride, polyethylene, polypropylene, Each resin film such as polystyrene, nylon, aromatic polyamide, polyetheretherketone, polysulfone, polyethersulfone, polyimide, polyetherimide, and triacetylcellulose, and further a resin film obtained by laminating two or more layers of the resin. Can be mentioned.

  In the image recording method described later, the support according to the present invention is developed with heat after forming a latent image to form an image. Therefore, a support that has been stretched into a film and heat-set is preferable in terms of dimensional stability. In addition, you may add fillers, such as a titanium oxide, a zinc oxide, barium sulfate, a calcium carbonate, in the range which does not inhibit the effect of this invention. In addition, the thickness of a support body is about 10-500 micrometers, Preferably it is 25-250 micrometers.

  As the protective layer used in the photothermographic material of the present invention, the binder resin described in the above photosensitive layer can be selected and used as necessary.

  As an additive to be added to the protective layer, it is preferable to contain a filler for the purpose of ensuring damage prevention and transportability of the image after heat development, and the content when the filler is added is in the layer forming composition. It is preferable to contain 0.05-30 mass%.

  Furthermore, in order to improve slipperiness and chargeability, the protective layer may contain a lubricant and an antistatic agent. Examples of such lubricants include fatty acids, fatty acid esters, fatty acid amides, and polyoxyethylene. , Polyoxypropylene, (modified) silicone oil, (modified) silicone resin, fluororesin, carbon fluoride, wax and the like, and antistatic agents include cationic surfactants, anionic surfactants Agents, nonionic surfactants, polymer antistatic agents, metal oxides or conductive polymers, etc., "11290 Chemical Products", Chemical Industry Daily, p. 875-876 etc., the compound described in US Patent No. 5,244,773 columns 14-20, etc. can be mentioned. Furthermore, various additives added to the photosensitive layer may be added to the protective layer as long as the object of the present invention is not impaired, and the amount of these additives added is 0.01 to 20 of the protective layer layer forming component. About mass% is preferable, More preferably, it is 0.05-10 mass%.

  In the present invention, the protective layer may be a single layer or a plurality of layers having the same or different composition. In addition, the film thickness of a protective layer is 1.0-5.0 micrometers normally.

  In the present invention, in addition to the above-described photosensitive layer, support and protective layer, an intermediate layer for improving film attachment between the support and the photosensitive layer is provided, and a backcoat layer is provided for the purpose of transportability and antistatic. When installed, the thickness of the intermediate layer is usually 0.05 to 2.0 μm, and the thickness of the backing layer is usually 0.1 to 10 μm.

  The coating solution for the photosensitive layer, the coating solution for the protective layer, and each coating solution for the intermediate layer and the backing layer that are installed according to the present invention are obtained by dissolving or dispersing the above-described components in a solvent, respectively. Can be prepared.

  Solvents that can be used in the above preparation may be those having a solubility parameter value in the range of 6.0 to 15.0 shown in “Solvent Pocket Book” edited by the Society of Synthetic Organic Chemistry. Examples of the solvent that can be used in the coating solution for forming each layer according to the invention include ketones such as acetone, isophorone, ethyl amyl ketone, methyl ethyl ketone, and methyl isobutyl ketone. Examples of alcohols include methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, diacetone alcohol, cyclohexanol, and benzyl alcohol. Examples of glycols include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, hexylene glycol and the like. Examples of ether alcohols include ethylene glycol monomethyl ether and diethylene glycol monoethyl ether. Examples of ethers include ethyl ether, dioxane, isopropyl ether and the like. Examples of the esters include ethyl acetate, butyl acetate, amyl acetate, isopropyl acetate and the like. Examples of hydrocarbons include n-pentane, n-hexane, n-heptane, cyclohexane, benzene, toluene, xylene and the like. Examples of the chlorides include methyl chloride, methylene chloride, chloroform, dichlorobenzene and the like, but are not limited to these as long as the effects of the present invention are not impaired.

These solvents can be used alone or in combination of several kinds. The residual amount of the solvent in the photothermographic material can be adjusted by appropriately setting the temperature conditions of the drying step after coating, and the residual solvent amount is preferably 5 to 1000 mg / m ^{2 in} total. more preferably 10-300 mg / m ^2.

  When dispersion is necessary when preparing the coating liquid, for example, a two-roll mill, a three-roll mill, a ball mill, a pebble mill, a cobol mill, a tron mill, a sand mill, a sand grinder, a Sqgvari attritor, a high-speed impeller disperser, a high-speed stone Conventionally known dispersers such as a mill, a high-speed impact mill, a disper, a high-speed mixer, a homogenizer, an ultrasonic disperser, an open kneader, and a continuous kneader can be selected and used as appropriate.

  To apply the coating solution prepared as described above, for example, extrusion-type extrusion coater, reverse roll coater, gravure roll coater, air doctor coater, blade coater, air knife coater, squeeze coater, impregnation coater, bar coater, Various known coater stations such as transfer roll coaters, kiss coaters, cast coaters, spray coaters and the like can be selected and used as appropriate. Among these coaters, it is preferable to use a roll coater such as an extrusion type extrusion coater or a reverse roll coater in order to eliminate unevenness in the thickness of the formation layer.

  Further, when the protective layer is applied, there is no particular limitation as long as the photosensitive layer is not damaged, but if the solvent used in the protective layer forming coating solution may dissolve the photosensitive layer, Among the above-described coater stations, an extrusion-type extrusion coater, a gravure roll coater, a bar coater, or the like can be used. Of these, when using a coating method such as a gravure roll coater or bar coater, the rotation direction of the gravure roll or bar may be forward or reverse with respect to the transport direction. A constant speed or a peripheral speed difference may be provided.

  Furthermore, when laminating each constituent layer, coating and drying may be repeated for each layer, but simultaneous multilayer coating may be performed by a wet-on-wet method and dried. In that case, for example, reverse roll coater, gravure roll coater, air doctor coater, blade coater, air knife coater, squeeze coater, impregnation coater, bar coater, transfer roll coater, kiss coater, cast coater, spray coater, etc. and extrusion type extrusion coater. In such a wet-on-wet multi-layer coating, the upper layer is applied while the lower layer is in a wet state. improves.

  Furthermore, in the present invention, it is preferable that the temperature at which the coating film is dried is in the range of 65 to 100 ° C. in order to effectively draw out the object of the present invention after at least the photosensitive layer coating solution is applied. When the drying temperature is lower than 65 ° C., the reaction is insufficient, and thus the sensitivity may vary with time. When the drying temperature is higher than 100 ° C., the photothermographic material itself immediately after production itself This is not preferable because it may cause fogging (coloring). The drying time cannot be generally defined by the air volume at the time of drying, but it is usually preferable to dry in the range of 2 to 30 minutes.

  The above-mentioned drying temperature may be dried immediately after coating at a drying temperature in the above-mentioned temperature range, or the vicinity of the surface caused by the marangony of the coating liquid generated during drying or the drying air of warm air is initially dried. For the purpose of preventing unevenness (scratch skin) caused by this, the initial drying temperature may be lower than 65 ° C., and then drying may be performed at a drying temperature in the above-described temperature range.

  As described above, the object of the present invention can be achieved by the photothermographic material of the present invention and the preferred production method thereof, but further, by optimizing the image recording method, a clear image without interference fringes can be obtained. Obtainable.

  Next, an image recording method suitable for the photothermographic material of the present invention will be described in detail.

  The image recording method that can be used in the present invention is roughly divided into three modes depending on the angle formed between the exposure surface and the laser beam, the wavelength of the laser, and the number of lasers used, and they may be performed alone, Two or more types may be combined, and by using such an image forming method, a clear image without interference fringes can be obtained.

  In the present invention, as an image recording method, an image may be formed by scanning exposure using a laser beam in which the angle formed by the laser beam and the exposure surface of the photothermographic material is not substantially perpendicular. To do. In this way, by shifting the incident angle from the vertical, even if reflected light at the interlayer interface is generated, the optical path difference reaching the photosensitive layer becomes large, so that scattering and attenuation of the laser light in the optical path occur. Interference fringes are less likely to occur. Here, “substantially not perpendicular” means that the angle that is closest to the vertical during laser scanning is preferably 55 ° to 88 °, more preferably 60 ° to 86 °, and still more preferably. It means 65 degrees or more and 84 degrees or less.

  Further, a more preferable aspect of the image recording method of the present invention is to form an image by scanning exposure using a vertical multi-laser having a non-single exposure wavelength. When scanning with such a vertical multi-laser beam having a width in wavelength, the generation of interference fringes is reduced as compared with a scanning laser beam of a vertical single mode. The term “vertical multi” as used herein means that the exposure wavelength is not single, and the normal exposure wavelength distribution is 5 nm or more, preferably 10 nm or more. The upper limit of the exposure wavelength distribution is not particularly limited, but is usually about 60 nm.

Furthermore, in the above-described image recording method, lasers used for scanning exposure are generally well-known solid lasers such as ruby laser, YAG laser, and glass laser; He—Ne laser, Ar ion laser, Kr ion laser, Gas lasers such as CO ₂ laser, CO laser, He—Cd laser, N ₂ laser, and excimer laser; semiconductor lasers such as InGaP laser, AlGaAs laser, GaAsP laser, InGaAs laser, InAsP laser, CdSnP ₂ laser, and GaSb laser; A laser, a dye laser, or the like can be selected and used in a timely manner, but in the image forming method according to claim 7, among these, a semiconductor laser having a wavelength of 600 to 1200 nm due to maintenance and the size of the light source. Is preferably used.

  In the laser used in a laser imager or a laser image setter, the beam spot diameter on the exposed surface of the heat-developable photographic material when scanned with the heat-developable photographic material is generally 5 to 75 μm as the minor axis diameter. The major axis diameter is in the range of 5 to 100 μm, and the laser beam scanning speed can be set to an optimum value for each photothermographic material depending on the sensitivity and laser power at the lasing wavelength inherent in the photothermographic material. it can.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, this invention is not limited to these.

Example 1
[Preparation of subtracted photographic support]
<Preparation of PET undercoated photographic support>
Corona of 8 W / m ² · min on both sides of a commercially available biaxially stretched heat-fixed thickness of 175 μm and blue-colored PET film having an optical density of 0.170 (measured with a Densitometer PDA-65 manufactured by Konica Corporation) Discharge treatment is performed, and the following undercoat coating liquid a-1 is applied on one surface so as to have a dry film thickness of 0.8 μm and dried to form an undercoat layer A-1, and on the opposite surface, The undercoating liquid b-1 was applied to a dry film thickness of 0.8 μm and dried to form an undercoat layer B-1.

<< Undercoat coating liquid a-1 >>
Butyl acrylate (30% by mass)
t-Butyl acrylate (20% by mass)
Styrene (25% by mass)
2-Hydroxyethyl acrylate (25% by mass)
270 g of copolymer latex liquid (solid content 30%)
C-1 0.6g
Hexamethylene-1,6-bis (ethylene urea) 0.8g
Finish to 1 liter with water 《Undercoating liquid b-1》
Butyl acrylate (40% by mass)
Styrene (20% by mass)
Glycidyl acrylate (40% by mass)
270 g of copolymer latex liquid (solid content 30%)
C-1 0.6g
Hexamethylene-1,6-bis (ethylene urea) 0.8g
Finish to 1 liter with water Subsequently, the upper surface of the undercoat layer A-1 and the undercoat layer B-1 was subjected to a corona discharge of 8 W / m ² · min. The undercoat layer coating liquid a-2 is used as an undercoat layer A-2 so that the dry film thickness is 0.1 μm. It was coated as an undercoating upper layer B-2 having an antistatic function so as to be 8 μm.

<< Undercoating upper layer coating liquid a-2 >>
Mass to become gelatin 0.4g / m ² C-1 0.2g
C-2 0.2g
C-3 0.1g
Silica particles (average particle size 3μm) 0.1g
Finish to 1 liter with water << Undercoating upper layer coating liquid b-2 >>
C-4 60g
Latex liquid containing C-5 as a component (solid content 20%) 80g
Ammonium sulfate 0.5g
C-6 12g
Polyethylene glycol (mass average molecular weight 600) 6g
Finish to 1 liter with water

<Back side application>
While stirring 830 g of methyl ethyl ketone (MEK), 84.2 g of cellulose acetate butyrate (Eastman Chemical Co., CAB381-20) and 4.5 g of a polyester resin (Bostic Co., VitelPE 2200B) were added and dissolved. Next, 0.57 mmol of infrared dye (described in Table 1) was added to the dissolved liquid, and 4.5 g of F-based activator (Asahi Glass Co., Surflon KH40) dissolved in 43.2 g of methanol and F 2.3 g of a system activator (Dainippon Ink Co., Ltd., MegaFag F120K) was added and stirred well until dissolved. Finally, 75 g of silica (WR Grace, Syloid 64X6000) dispersed in methyl ethyl ketone at a concentration of 1% by mass with a dissolver type homogenizer was added and stirred to prepare a coating solution for the back surface side.

  The back surface coating solution thus prepared was applied and dried by an extrusion coater so that the dry film thickness was 3.5 μm. It dried for 5 minutes using the drying air with a drying temperature of 100 degreeC, and dew point temperature of 10 degreeC.

<< Preparation of photosensitive silver halide emulsion A >>
A1
Phenylcarbamoylated gelatin 88.3g
Compound (A) (10% methanol aqueous solution) 10 ml
Potassium bromide 0.32g
Finish to 5429 ml with water B1
0.67 mol / L silver nitrate aqueous solution 2635 ml
C1
Potassium bromide 51.55g
Potassium iodide 1.47g
Finish to 660ml with water D1
Potassium bromide 154.9g
4.41 g of potassium iodide
Iridium chloride (1% solution) 0.93ml
Finish up to 1982ml with water E1
0.4 mol / L potassium bromide aqueous solution The following silver potential control amount F1
Potassium hydroxide 0.71g
Finish to 20ml with water G1
56% acetic acid aqueous solution 18.0 ml
H1
Anhydrous sodium carbonate 1.72 g
Finish to 151 ml with water Compound (A):
_{HO (CH 2 CH 2 O)} n - (CH (CH 3) CH 2 O) 17 - (CH 2 CH 2 O) m H
(M + n = 5-7)
Using the mixing stirrer shown in Japanese Patent Publication Nos. 58-58288 and 58-58289, the solution (A1) is controlled to 1/4 of the solution (B1) and the total amount of the solution (C1) to 45 ° C. and pAg 8.09. While adding 4 minutes 45 seconds by the simultaneous mixing method, nucleation was performed. After 1 minute, the entire amount of solution (F1) was added. During this time, pAg was adjusted appropriately using (E1). After 6 minutes, 3/4 amount of the solution (B1) and the whole amount of the solution (D1) were added over 14 minutes and 15 seconds by the simultaneous mixing method while controlling the temperature at 45 ° C. and pAg 8.09. After stirring for 5 minutes, the temperature was lowered to 40 ° C., the whole amount of the solution (G1) was added, and the silver halide emulsion was precipitated. The supernatant was removed leaving 2000 ml of the sediment, 10 liters of water was added, and after stirring, the silver halide emulsion was sedimented again. The remaining portion of 1500 ml was left, the supernatant was removed, 10 liters of water was added, and after stirring, the silver halide emulsion was precipitated. After leaving 1500 ml of the sedimented portion and removing the supernatant, the solution (H1) was added, the temperature was raised to 60 ° C., and the mixture was further stirred for 120 minutes. Finally, the pH was adjusted to 5.8, and water was added so that the amount of silver was 1161 g per mole of silver, whereby photosensitive silver halide emulsion A was obtained.

  This emulsion was monodisperse cubic silver iodobromide grains having an average grain size of 0.058 μm, a grain size variation coefficient of 12%, and a [100] face ratio of 92%.

  Next, 240 ml of sulfur sensitizer S-5 (0.5% methanol solution) was added to the above emulsion, and gold sensitizer Au-5 corresponding to 1/20 mol of this sensitizer was added, and 120 ° C. at 120 ° C. Chemical sensitization was performed by stirring for a minute.

<< Preparation of powdered organic silver salt A >>
130.8 g of behenic acid, 67.7 g of arachidic acid, 43.6 g of stearic acid, and 2.3 g of palmitic acid were dissolved in 4720 ml of pure water at 80 ° C. Next, 540.2 ml of a 1.5 M / L sodium hydroxide aqueous solution was added, and 6.9 ml of concentrated nitric acid was added, followed by cooling to 55 ° C. to obtain a fatty acid sodium solution. While maintaining the temperature of the fatty acid sodium solution at 55 ° C., 45.3 g of the photosensitive silver halide emulsion A and 450 ml of pure water were added and stirred for 5 minutes.

  Next, 702.6 ml of 1 M / L silver nitrate solution was added over 2 minutes and stirred for 10 minutes to obtain an organic silver salt dispersion. Thereafter, the obtained organic silver salt dispersion was transferred to a water-washing container, deionized water was added and stirred, and then allowed to stand to float and separate the organic silver salt dispersion, thereby removing the lower water-soluble salts. Thereafter, washing with deionized water and drainage were repeated until the electrical conductivity of the drainage reached 2 μS / cm, and centrifugal dehydration was carried out. Then, the resulting cake-like organic silver salt was converted into an airflow dryer flash jet dryer (stock) The product was dried until the water content became 0.1% according to the operating conditions of nitrogen gas atmosphere and dryer inlet hot air temperature to obtain a dried organic silver salt A of organic silver salt.

  An infrared moisture meter was used to measure the moisture content of the organic silver salt composition.

<< Preparation of Preliminary Dispersion A >>
14.57 g of polyvinyl butyral powder (Monsanto, Butvar B-79) was dissolved in 1457 g of methyl ethyl ketone, and 500 g of powdered organic silver salt A was gradually added while stirring with a dissolver DISPERMAT CA-40M manufactured by VMA-GETZMANN. Preliminary dispersion A was prepared by thorough mixing.

<< Preparation of photosensitive emulsion dispersion 1 >>
Media type disperser DISPERMAT SL- filled with 80% of the internal volume of 0.5 mm diameter zirconia beads (Torayserum manufactured by Toray) so that the residence time in the mill is 1.5 minutes using a pump. Photosensitive emulsion dispersion 1 was prepared by supplying to C12EX type (VMA-GETZMANN) and dispersing at a mill peripheral speed of 8 m / s.

<< Preparation of stabilizer liquid >>
A stabilizer solution was prepared by dissolving 1.0 g of Stabilizer 1 and 0.31 g of potassium acetate in 4.97 g of methanol.

<< Preparation of infrared sensitizing dye liquid A >>
19.2 mg of sensitizing dye 1, 1.488 g 2-chloro-benzoic acid, 2.7779 g stabilizer 2 and 365 mg 5-methyl-2-mercaptobenzimidazole in 31.3 ml MEK in the dark It melt | dissolved and the infrared sensitizing dye liquid A was prepared.

<< Preparation of Additive Liquid a >>
27.98 g and 1.54 g of 4-methylphthalic acid and 0.92 mmol of infrared dye (described in Table 1) were dissolved in 110 g of MEK to obtain additive solution a.

<< Preparation of additive liquid b >>
3.56 g of antifoggant 2 and 3.43 g of phthalazine were dissolved in 40.9 g of MEK to obtain additive liquid b.

<< Preparation of photosensitive layer coating solution >>
In an inert gas atmosphere (97% nitrogen), the photosensitive emulsion dispersion 1 (50 g) and 15.11 g of MEK were kept at 21 ° C. with stirring, and 390 μl of antifoggant 1 (10% methanol solution) was added, Stir for 1 hour. Further, 494 μl of calcium bromide (10% methanol solution) was added and stirred for 20 minutes. Subsequently, 167 ml of a stabilizer solution was added and stirred for 10 minutes, and then 1.32 g of the infrared sensitizing dye solution was added and stirred for 1 hour. Thereafter, the temperature was lowered to 13 ° C. and further stirred for 30 minutes. While keeping the temperature at 13 ° C., 13.31 g of polyvinyl butyral (Monsanto Butvar B-79) was added and stirred for 30 minutes, and then 1.084 g of tetrachlorophthalic acid (9.4 mass% MEK solution) was added. Stir for 15 minutes. While further stirring, 12.43 g of additive liquid a, 1.6 ml of Desmodur N3300 / Mobey aliphatic isocyanate (10% MEK solution), 4.27 g of additive liquid b were sequentially added and stirred. A photosensitive layer coating solution was obtained.

<Preparation of matting agent dispersion>
Cellulose acetate butyrate (Eastman Chemical Co., 7.5 g CAB171-15) was dissolved in 42.5 g of MEK, and 5 g of calcium carbonate (Speciality Minerals, Super-Pflex 200) was added thereto, and a dissolver type homogenizer was used. A matting agent dispersion was prepared by dispersing at 8000 rpm for 30 minutes.

<< Preparation of surface protective layer coating liquid >>
While stirring 865 g of MEK (methyl ethyl ketone), 96 g of cellulose acetate butyrate (Eastman Chemical Co., CAB171-15), 4.5 g of polymethylmethacrylic acid (Rohm & Haas Co., Paraloid A-21), vinyl sulfone compound ( VSC) (1.5 g), benztriazole (1.0 g), and F-based activator (Asahi Glass Co., Surflon KH40) (1.0 g) were added and dissolved. Next, 30 g of the above matting agent dispersion was added and stirred to prepare a surface protective layer coating solution.

<Photosensitive layer side coating>
The photosensitive material was prepared by simultaneously applying the photosensitive layer coating solution and the surface protective layer coating solution using an extrusion coater. The coating was carried out so that the photosensitive layer had an applied silver amount of 1.9 g / m ² and the surface protective layer had a dry film thickness of 2.5 μm. Thereafter, drying was performed for 10 minutes using a drying air having a drying temperature of 75 ° C. and a dew point temperature of 10 ° C. to obtain a coated sample (heat-developable photographic material).

<< Exposure and development process >>
From the emulsion surface side of the photosensitive material produced as described above, exposure by laser scanning was given by an exposure machine using a semiconductor laser having a wavelength of 810 nm as an exposure source. At this time, an image was formed with the angle of the exposure surface of the photosensitive material and the exposure laser beam being 75 degrees.

  Thereafter, an automatic developing machine having a heat drum was used for heat development at 123 ° C. for 15 seconds so that the protective layer of the photosensitive material was in contact with the drum surface. At that time, exposure and development were performed in a room adjusted to 23 ° C. and 50% RH.

"Evaluation of sharpness"
Three coated samples were placed in a sealed container whose interior was maintained at 25 ° C. and relative humidity 55%, and then aged for 20 days at 40 ° C. or 7 days at 60 ° C. A chest image (image sample obtained using a chest phantom) was output for the second piece in each sample, and this image was visually observed to determine sharpness according to the following criteria.
A: Very sharp B: Good but slightly blurred C: Blur is conspicuous and there is a slight hindrance to interpretation D: Difficult to interpret due to blur

  From Table 1, it can be seen that, when the infrared dye of the present invention is used, sharpness is superior in storage at high temperature and high humidity as compared with comparison.

Claims (5)

In a photothermographic material having at least one photosensitive layer containing photosensitive silver halide on a support, at least one of the compounds represented by the following general formula ( 2 ) is provided on at least one or both of the support. A photothermographic material comprising a seed-containing layer.

(In the formula, R ₁₁ and R ₁₂ each independently represent a hydrogen atom or a substituent. Z ₁₁ represents O, S, N—R ₁ , Se or Te, and R ₁ represents an alkyl group or an aryl group. Q ₁₁ represents a 6-membered heterocyclic ring, A ₂₁ and B ₂₁ represent an aryl group, provided that A ₂₁ and B ₂₁ are not the same aryl group . The photothermographic material according to claim 1, wherein the compound represented by the general formula ( 2 ) is a compound represented by the following general formula ( 5 ).

_(Wherein, R _{11, R 12} and Z ₁₁ have the same meaning as _{R 11, R 12} and Z ₁₁ in the general formula (2). _Z 12 _{is, O, S, N-R} 2, Se or Te the stands, _{.A 21} and _{B 21 R 2} represents an alkyl group or an aryl group has the same meaning as _{a 21} and _{B 21} in the general formula (2).) 3. The photothermographic material according to claim 1, wherein the compound represented by the general formula ( 5 ) is a compound represented by the following general formula ( 6 ).

_{(Wherein, R 11} and R _{1 2} is the generally formula synonymous with _{R 11} and R _{1 2} of (2). _{A 21} and _{B 21} is the _{A 21} and _{B 21} in the general formula (2) Synonymous. ) An image forming method, wherein the photothermographic material according to claim 1 is exposed to light using a laser light source and then developed at 80 to 150 ° C. A squarylium compound represented by the following general formula (6):

(It _{wherein, R 11} and _{R 12,} is _{.A 21} and _{B 21} each independently represent a hydrogen atom or a substituent, which represents an aryl group. _{However, A 21} and _{B 21} are the same aryl groups from one another No.)