JPH09304869A - Heat developable photosensitive material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the occurrence of interference fringes in an image at the time of exposure with laser light of a specified wavelength by forming a photosensitive silver halide emulsion layer and specifying the particle size of the silver halide and the absorbance of the emulsion layer at the wavelength. SOLUTION: This heat developable photosensitive material has a photosensitive silver halide emulsion layer on the substrate and is exposed with laser light of >=700nm wavelength. The particle size of the silver halide in the emulsion layer is <=0.1μm and the absorbance of the emulsion layer at the wavelength is >=0.3. This photosensitive material is preferably exposed using a laser scanning exposure system so that the angle between the exposed surface and scanning laser light is not practically made right and interference fringes in an image are improved. Laser scanning exposure using a semiconductor laser diode is also preferably carried out. In this case, the wavelength region of light for exposure is 700-1,500nm.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a photothermographic material,
In particular, it relates to a photothermographic material for laser exposure.

[0002]

2. Description of the Related Art Hitherto, as a means for outputting image information such as MRI and X-ray CT, a method of exposing a photosensitive material by scanning a laser beam has been used. In recent years, a semiconductor laser diode having a high output and a high stability has been widely used as a light source.

By the way, in the case of a system which does not have a fixing process for dissolving and removing silver halide such as a heat development process, a photosensitive material which is free from haze is required. Therefore, it is necessary to make fine silver halide grains.

However, such fine emulsion particles or a highly transparent light-sensitive material are liable to cause interference fringes resulting from reflection of laser light inside the light-sensitive material. Regarding this interference fringe, Japanese Patent Publication No. 6-10735 proposes an improvement with a photosensitive material, but this does not eliminate the interference fringe.

Improvements have also been attempted in laser scanning exposure. Japanese Patent Laid-Open No. 5-113548 discloses a method in which laser scanning exposure is performed by shifting the reflected light from the upper and lower boundary surfaces of the transparent layer so that they do not interfere with each other, but the refractive index differs from that of the support. If there are multiple layers, the interference fringes will not disappear.

[0006]

SUMMARY OF THE INVENTION The object of the present invention is to
It is an object of the present invention to provide a photothermographic material which does not cause interference fringes in an image when exposed to laser light having a wavelength of 0 nm or more.

[0007]

The above object is achieved by the following specific items. (1) having a photosensitive silver halide emulsion layer on a support,
A photothermographic material which is exposed to a laser beam having a wavelength of 00 nm or more, wherein the grain size of silver halide in the photosensitive silver halide emulsion layer is 0.1 μm or less, and the photosensitive silver halide emulsion layer is Is a photothermographic material having an absorbance of 0.3 or more at the exposure wavelength. (2) The exposure is performed by a laser scanning exposure machine in which the angle between the exposed surface of the photosensitive material and the scanning laser light is not substantially vertical, and the interference fringes in the image are improved (1) Photothermographic material. (3) The photothermographic material according to the above (1), which is exposed by a laser scanning exposure machine in which scanning laser light is longitudinal multi, and has improved interference fringes in an image. (4) The above (2) or (3), which has a photosensitive silver halide emulsion layer having a refractive index different from that of the support, and a protective layer having a refractive index different from that of the photosensitive silver halide emulsion layer on the support. ) Photothermographic material.

[0008]

Embodiments of the present invention will be described below in detail.

The photothermographic material of the present invention has at least one photosensitive silver halide emulsion layer on a support, and
It is exposed with laser light having a wavelength of 0 nm or more. Specifically, it is preferable to perform laser scanning exposure with a laser light source, preferably using a semiconductor laser diode which is inexpensive and easily available. In this case, the wavelength range of exposure is 700 to 1500 nm, and preferably 750 to 1000 nm. This is because, in the case of a photothermographic material, even if a sensitizing dye or dye having λ _{max in} this wavelength region remains in the photothermographic material, there is no problem in reading the transmitted image.

The photosensitive silver halide emulsion layer (hereinafter sometimes simply referred to as "photosensitive emulsion layer") of the photothermographic material of the present invention has a silver halide grain size of 0.1.
It is less than μm. This will be described later.

The photosensitive emulsion layer has an exposure wavelength of 0.3.
The absorbance is above, and preferably 0.3 to 1.5. Such absorbance is obtained by using a sample in which a photosensitive emulsion layer is formed on one surface of a support, setting the photosensitive emulsion surface toward the light source side, and subtracting the support as a reference. is there. The measurement may be directly performed using a sample in which a protective layer and the like are provided on the photosensitive emulsion layer.

When the photothermographic material of the present invention has a plurality of photosensitive emulsion layers, it is preferred that the silver halide grain size and the absorbance of all the photosensitive emulsion layers are within the above ranges.

The absorbance when a plurality of photosensitive emulsion layers are present is obtained by using a sample in which a photosensitive emulsion layer having the same constitution as the photothermographic material is provided on one surface of the support. Alternatively, a plurality of samples having one photosensitive emulsion layer may be prepared.

In the case of a photothermographic material having a photosensitive emulsion layer on both sides of a support, the absorbance is the same as the photosensitive emulsion layers present on one side of the support. It was obtained by preparing each sample in which the layers were provided and using these samples.

When the silver halide grains in the photosensitive emulsion layer are atomized as described above, interference fringes are likely to occur. However, by controlling the absorbance of the photosensitive emulsion layer within the above range,
Generation of interference fringes is suppressed. On the other hand, if the absorbance of the photosensitive emulsion layer is less than 0.3, the interference fringes will not disappear.

Particularly, in the sense of effectively obtaining the effects of the present invention, a support having a photosensitive emulsion layer on one surface thereof and a protective layer on the photosensitive emulsion layer, or the back surface of the support. Having a back layer or the like, or having both of them, the supports and the photosensitive emulsion layers have different refractive indices, and the photosensitive emulsion layer and the protective layer, and / or
Alternatively, when the photothermographic material has a different refractive index between the support and the back layer, the effect is particularly great when the photothermographic material is such a material. When there are a plurality of layers having different refractive indexes, a plurality of interference fringes are generated due to reflection at each interface, and it is difficult to take countermeasures in each layer, and countermeasures to the photosensitive emulsion layer are strongly desired. .

In the photothermographic material of the present invention, the support has a refractive index of 1.660 to 1.668 and the photosensitive emulsion layer has a refractive index of 1.650 to 1.660. A layer having a refractive index different from that of the layer, for example, a protective layer has a refractive index of 1.669 to 1.680. The refractive index can be measured by a refractometer. For example, an Abbe refractometer using a sodium lamp is used.

Usually, the difference in refractive index between the support and the photosensitive emulsion layer is about 0.005 to 0.02, and the difference in refractive index between the photosensitive emulsion layer and the protective layer is 0.01 to 0.02. It is about 03. In such a case, the means of the present invention is effective.

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

Here, the phrase "substantially vertical" does not mean that the angle is the most vertical during laser scanning, and is preferably 3 degrees or more and 45 degrees or less, more preferably 5 degrees or more and 25 degrees or less, and further preferably. Means that the angle deviates from the vertical by 7 degrees or more and 20 degrees or less, and most preferably 10 degrees or more and 18 degrees or less.

The beam spot diameter on the exposed surface of the photosensitive material when the laser light is scanned on the photosensitive material is preferably 200 μm or less, more preferably 100 μm or less. It is preferable that the spot diameter is smaller because the angle of deviation of the laser incident angle from the vertical can be reduced. The lower limit of the beam spot diameter is usually 10 μm.

By performing such laser scanning exposure, the effect of suppressing the generation of interference fringes is improved.

The exposure in the present invention is also preferably carried out using a laser scanning exposure machine which emits scanning laser light having a longitudinal multi-direction. The effect of suppressing the generation of interference fringes is improved as compared with the vertical single mode scanning laser light.

In order to make the vertical multi, it is preferable to use a method of returning light by multiplexing, applying a high frequency superposition, or the like.
Vertical mulching means that the exposure wavelength is not single, and normally the distribution of the exposure wavelength 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.

In the present invention, a dye having a λ _max according to the exposure wavelength may be used in order to make the absorbance at the exposure wavelength of the photosensitive emulsion layer 0.3 or more.

Examples of dyes that can be used in the present invention include many dyes such as oxonol, cyanine, merocyanine, anthraquinone, and arylmethane. Particularly, a cyanine dye represented by the following formula (1a) and a squarylium dye represented by the following formula (2) are preferable.

[0027]

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In the formula (1a), Z ¹ and Z ² each represent a group of non-metal atoms necessary for forming a 5- or 6-membered nitrogen-containing heterocycle (each may have a condensed ring), R ¹ and R ² each represent an alkyl group, an alkenyl group or an aralkyl group, L represents a linking group formed by linking 5, 7 or 9 methine groups by a conjugated double bond, and a, b or c represents Each represents 0 or 1, and X ⁻ represents an anion.

In the formula (1a), the 5- or 6-membered nitrogen-containing heterocycle formed by Z ¹ or Z ² (may have a condensed ring), an oxazole ring, an isoxazole ring,
Benzoxazole ring, naphthoxazole ring, thiazole ring, benzothiazole ring, naphthothiazole ring, indolenine ring, benzoindolenine ring, imidazole ring, benzimidazole ring, naphthimidazole ring, imidazoquinoxaline ring, quinoline ring, pyridine ring, pyrrolo Examples thereof include a pyridine ring and a furopyrrole ring. A 5-membered nitrogen-containing heterocycle in which a benzene ring or a naphthalene ring is condensed is preferable, and an indolenine ring is most preferable. These rings may be substituted. As the substituent, for example, an alkyl group (eg, methyl, ethyl), an alkoxy group (eg, methoxy, ethoxy), a phenoxy group (eg, unsubstituted phenoxy,
p-chlorophenoxy), halogen atom (Cl, Br,
F), an alkoxycarbonyl group (for example, ethoxycarbonyl), a cyano group, a nitro group, a carboxy group and the like. More preferably, it is an indolenine ring substituted or unsubstituted with a chlorine atom, a methoxy group or a methyl group.

The alkyl group represented by R ¹ and R ² is
It is an alkyl group having 1 to 20 carbon atoms, and more preferably 1 to 8 (eg, methyl, ethyl, propyl, butyl, isobutyl, pentyl, hexyl). Further, these alkyl groups may be substituted with a halogen atom (F, Cl, Br), an alkoxycarbonyl group (eg, methoxycarbonyl, ethoxycarbonyl), a hydroxy group or the like.

The aralkyl group represented by R ¹ and R ² is preferably an aralkyl group having a carbon number of 7 to 12 (eg, benzyl, phenylethyl) and has a substituent (eg, methylalkoxy, chloro atom). You may have.

The alkenyl group represented by R ¹ and R ² is preferably an alkenyl group having 2 to 6 carbon atoms,
For example, 2-pentenyl group, vinyl group, allyl group, 2-
Examples thereof include butenyl group and 1-propenyl group.

In the formula (1a), L is 5, 7 or 9
Is a linking group in which two methine groups are conjugated. The number of methine groups is preferably 7 (heptamethine compound).

The methine group may have a substituent. However, the methine group having a substituent is at the central (meso) position.
It is preferably a substituted methine group. Preferred among the methine groups represented by L are those represented by the following formula (L5) (pentamethine), formula (L7) (heptamethine) and formula (L9) (nonamethine).

[0035]

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In the formula, R ⁴ is a hydrogen atom, an alkyl group, a halogen atom, an aryl group, NR ⁶ R ⁷ , SR ⁸ or OR ⁸
(R ⁶ , R ⁷ and R ⁸ each represent an alkyl group or an aryl group). R ⁶ and R ⁷ are linked,
Heterocycles (eg piperidine, morpholine) may be formed. R ³ and R ⁵ represent a hydrogen atom or an atomic group necessary for bonding with each other to form a 5- or 6-membered ring, and R ⁹ and R ¹⁰ are a hydrogen atom or an alkyl group, respectively. R ³ and R ⁵ are bonded to each other to form a 5-membered or 6-membered
It is preferable to form a member ring. Examples of the ring to be formed include a cyclopentene ring and a cyclohexene ring. The rings may have a substituent (for example, an alkyl group or an aryl group).

The above alkyl group has the same meaning as the alkyl group of R ¹ and R ² . The halogen atom is F or C
l and Br. The aryl group preferably has 6 to 12 carbon atoms, and examples thereof include a phenyl group and a naphthyl group. The aryl group may be substituted, and as the substituent, an alkyl group having 10 or less carbon atoms, preferably 6 or less carbon atoms (eg, methoxy, ethyl, butyl, hexyl), and 10 or less carbon atoms, preferably 6 or less carbon atoms An alkoxy group (eg, methoxy, ethoxy), an aryloxy group having 20 or less, preferably 12 or less carbon atoms (eg,
Phenoxy, p-chlorophenoxy), a halogen atom (Cl, Br, F), having 10 or less carbon atoms, preferably 6
The following alkoxycarbonyl groups (eg, ethoxycarbonyl), cyano groups, nitro groups and carboxyl groups are included.

In the formula (1a), a, b and c are
It is 0 or 1, respectively. a and b are preferably 0. c is generally 1. However, when an anionic substituent such as carboxyl forms an intramolecular salt with N ⁺ , c becomes 0.

[0039] X ^- include anions represented by halogen ions ^{(Cl -, Br -, I} -), p- toluenesulfonate ion, ethyl sulfate ion, PF ₆ ^-, BF ₄ ^- and the like ^- and ClO ₄ Can be mentioned.

Among the expressions (1a), the following expression (1
The cyanine dyes indicated under b) are preferred.

[0041]

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In the formula (1b), Z ³ and Z ⁴ each represent an atom necessary for forming a benzo or naphtho condensed ring,
R ¹ and R ² each represent an alkyl group, an aralkyl group or an alkenyl group, R ³ and R ⁵ each represent a hydrogen atom or an atomic group necessary for connecting with each other to form a 5- or 6-membered ring, R ⁴ Represents a hydrogen atom, an alkyl group, a halogen atom, an aryl group, NR ⁶ R ⁷ , SR ⁸ or OR ⁸ , R ⁶ , R ⁷ and R ⁸ each represent an alkyl group or an aryl group, and R ⁶ and R ⁷ are They may be linked to each other to form a 5- or 6-membered ring. R ^11, R ^12, R ¹³ and R ¹⁴ each represent an alkyl group, R ¹¹ and R ¹² and R
¹³ and R ¹⁴ may combine to form a ring. X ^- is an anion, c is 0 or 1.

In the formula (1b), the benzo- or naphtho-condensed ring formed by Z ³ or Z ⁴ may be substituted with the above-mentioned substituents such as Z ¹ .

R ¹ , R ² , R ⁶ , R ⁷ , R ⁸ , R ¹¹ , R
^The alkyl groups represented by ¹² , R ¹³ and R ¹⁴ are represented by the formula (1
It is synonymous with the alkyl group in R ¹ etc. of a). R ¹¹ and R ¹² , and R ¹³ and R ¹⁴ may be linked to each other to form a ring (eg, cyclohexane).

The alkenyl group and aralkyl group represented by R ¹ and R ² have the same meaning as the alkenyl group and aralkyl group of R ¹ and R ^{2 in} the formula (1a).

The aryl group represented by R ⁴ , R ⁶ , R ⁷ and R ⁸ has the same meaning as the aryl group described for R ⁴ in the formula (L5).

The halogen atom of R ⁴ is, R ⁴ of formula (L5)
Is synonymous with the halogen atom of.

The ring formed by R ³ and R ⁵ has the same meaning as the ring formed by R ³ and R ⁵ of formula (L7).

The ring formed by R ⁶ and R ⁷ are as defined ring formation by R ⁶ and R ⁷ of formula (L7).

X has the same meaning as X in formula (1a).

C has the same meaning as c in the formula (1a).

The most preferred cyanine dye is that R ¹ and R ² are alkyl groups, R ¹¹ , R ¹² , R ¹³ and R ¹⁴ are methyl groups, and R ³ and R ^{5 form} a cyclopentene ring or a cycloheptene ring. R ⁴ is a diphenylamino group or a chloro atom.

The squarylium dye represented by the following formula (2) is also particularly effective.

[0054]

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In formula (2), R ¹⁵ , R ¹⁶ , R ¹⁷ , R ¹⁸ and R
¹⁹ , R ²⁰ , R ²¹ and R ²² each represent a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group or an aralkyl group, and R ¹⁵ and R ¹⁶ and / or R ¹⁷ and R ¹⁸ and / or R ¹⁹ and R ²⁰ and / or R ²¹ and R ²² or R ¹⁶ and R ¹⁷ and / or R ²⁰ and R ²¹ may form a 5- or 6-membered ring.

In the formula (2), R ¹⁵ , R ¹⁶ , R ¹⁷ , R
^The alkyl group and aralkyl group represented by ¹⁸ , R ¹⁹ , R ²⁰ , R ²¹ and R ²² are synonymous with the alkyl group and aralkyl group represented by R ¹ of the formula (1a). R ¹⁵ ,
Examples of the cycloalkyl group represented by R ¹⁶ , R ¹⁷ , R ¹⁸ , R ¹⁹ , R ²⁰ , R ²¹ and R ²² include a cyclopentyl group and a cyclohexyl group. R ¹⁵ , R ¹⁶ , R
^The aryl group represented by ¹⁷ , R ¹⁸ , R ¹⁹ , R ²⁰ , R ²¹ and R ²² has the same meaning as the aryl group of R ^{4 in} formula (L5).

Specific compound examples of dyes preferably used in the present invention are shown below.

[0058]

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[0059]

[Chemical 6]

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[Chemical 7]

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[0065]

[Chemical 12]

[0066]

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[0067]

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[0068]

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[0069]

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[0070]

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The compounds of the present invention are described in US 3,671,64
No. 8, US Pat. No. 2,095,854, JP-A-6-4358.
No. 3, US Pat. No. 5,380,635 and the like and the following synthesis examples.

Synthesis Example (Synthesis of Compound 1-2) 1,2,3,3-tetramethyl-5-chloro-p-toluenesulfonate 11.4
g, N- (2,5-dianilinomethylenecyclopentylidene) -diphenylaminium tetrafluoroborate 7.2 g, ethyl alcohol 100 ml, acetic anhydride 6 ml, and triethylamine 12 ml were stirred at an external temperature of 100 ° C. for 1 hour for deposition. The crystals were filtered off. Methyl alcohol 1
The crystals were recrystallized from 00 ml to obtain 7.3 g of compound 1-2.

Melting point: 270 ° C. or higher, λ _max : 800.8
nm ε: 2.14 × 10 ⁵ (chloroform)

Other compounds can be similarly synthesized.

Such dyes may be added so that the light-sensitive emulsion layer has an absorbance of 0.3 or more at the exposure wavelength, and one kind may be used, or two or more kinds may be used in combination. Such a dye may be used by adding it to the coating solution for the photosensitive emulsion layer. The usual addition amount is 1 mg to ² per 1 m ² of the light-sensitive material.
It is about g. In addition, bis [2- (3,5-di-ter
t-butyl-o-benzoquinone monoimide) -4,6-
It may be used in combination with other dyes such as di-tert-butylphenolato] calcium (II).

As a result, these dyes may coincide with the spectral sensitizing dyes described later, or may have similar absorption characteristics, but since the spectral sensitizing dyes are adsorbed on silver halide. , Contributes little to the absorbance of the photosensitive emulsion layer.

The method for forming the photosensitive silver halide in the present invention is well known in the art, and for example, the method described in Research Disclosure, June 1978, No. 17029, and US Pat. No. 3,700,458 is used. be able to. Specific methods that can be used in the present invention include a method of converting a part of the silver of the organic silver salt to a photosensitive silver halide by adding a halogen-containing compound to the prepared organic silver salt, gelatin. Alternatively, a method of preparing a photosensitive silver halide grain by adding a silver supply compound and a halogen supply compound to another polymer solution and mixing the resultant with an organic silver salt can be used. In the present invention, the latter method can be preferably used.

The grain size of the photosensitive silver halide is preferably small for the purpose of suppressing white turbidity after image formation. Specifically, as described above, it is 0.1 μm or less, preferably 0.01 μm. It is preferably 0.08 μm or more, more preferably 0.02 μm or more and 0.06 μm or less. Here, the grain size means the length of the edge of the silver halide grain when the silver halide grain is a cubic or octahedral so-called normal crystal. In the case where the silver halide grains are tabular grains, the diameter refers to a diameter when converted into a circular image having the same area as the projected area of the main surface. In the case of other non-normal crystals, for example, in the case of spherical grains, rod-shaped grains, etc., it means the diameter when considering a sphere equivalent to the volume of silver halide grains.

The silver halide grains have a cubic shape,
Octahedral, tabular particles, spherical particles, rod-like particles, potato-like particles and the like can be mentioned, and in the present invention, cubic particles and tabular particles are particularly preferable. The average aspect ratio when using tabular silver halide grains is preferably 100: 1 to 2: 1, more preferably 50: 1 to 3: 1.
Is good. Further, grains having rounded corners of silver halide grains can also be preferably used. The surface index (mirror index) of the outer surface of the photosensitive silver halide grains is not particularly limited. However, the spectral sensitization efficiency when the spectral sensitizing dye is adsorbed is high. preferable. The ratio is preferably 50% or more, and 65%
The above is more preferable, and 80% or more is further preferable. The ratio of Miller index {100} planes is determined by T.W. using the adsorption dependence of {111} planes and {100} planes in the adsorption of sensitizing dyes. Tani: J. Imaging Sci. , 2
9, 165 (1985). The halogen composition of the photosensitive silver halide is not particularly limited, and may be any of silver chloride, silver chlorobromide, silver bromide, silver iodobromide, silver iodochlorobromide, and silver iodide, In the present invention, silver bromide or silver iodobromide can be preferably used. Silver iodobromide is particularly preferred, and the silver iodide content is preferably 0.1 mol% or more and 40 mol% or less, more preferably 0.1 mol% or more and 20 mol% or less. The distribution of the halogen composition in the grains may be uniform, the halogen composition may be changed stepwise, or may be changed continuously, but as a preferred example, the silver iodide content inside the grains is High silver iodobromide grains can be used. Further, silver halide grains having a core / shell structure can be preferably used. The structure is preferably a 2- to 5-fold structure,
More preferably, core / shell particles having a double to quadruple structure can be used.

The photosensitive silver halide grain of the present invention preferably contains at least one metal complex selected from rhodium, rhenium, ruthenium, osmium, iridium, cobalt or iron. These metal complexes are 1
They may be of the same kind, or two or more kinds of complexes of the same metal and different metals may be used in combination. The preferable content is in the range of 1 × 10 ⁻⁹ mol to 1 × 10 ⁻² mol per mol of silver,
The range of 1 × 10 ⁻⁸ mol to 1 × 10 ⁻⁴ is more preferable.
As a specific structure of the metal complex, JP-A-7-22544 is used.
A metal complex having a structure described in No. 9 or the like can be used. As the compound of cobalt and iron, a hexacyano metal complex can be preferably used. Specific examples are shown below.

[Fe (CN) ₆ ] ^4- [Fe (CN) ₆ ] ^3- [Co (CN) ₆ ] ^3-

The metal complex-containing phase in the silver halide may be uniform, may be contained in the core portion at a high concentration, or may be contained in the shell portion at a high concentration, and is not particularly limited.

The photosensitive silver halide grains can be desalted by washing with water by a method known in the art such as a noodle method and a flocculation method. In the present invention, it may or may not be desalted. Good.

The photosensitive silver halide grains in the invention are preferably chemically sensitized. As a preferred chemical sensitization method, a sulfur sensitization method, a selenium sensitization method, and a tellurium sensitization method are well known in the art. Further, a noble metal sensitization method or a reduction sensitization method of a gold compound, platinum, palladium, an iridium compound or the like can be used. As the compound preferably used in the sulfur sensitization method, the selenium sensitization method, and the tellurium sensitization method, known compounds can be used, and the compounds described in JP-A-7-128768 can be used. Examples of tellurium sensitizers include diacyl tellurides, bis (oxycarbonyl) tellurides, bis (carbamoyl) tellurides, diacyl tellurides, bis (oxycarbonyl) ditellurides, bis (carbamoyl) ditellurides, P = Te Compounds having a bond, tellurocarboxylates, Te-organyl
Tellurocarboxylic acid esters, di (poly) tellurides,
Tellurides, tellurols, telluroacetals, tellurosulfonates, compounds having a P—Te bond, T-containing
e Heterocycles, tellurocarbonyl compounds, inorganic tellurium compounds, colloidal tellurium, and the like can be used. Compounds preferably used in the noble metal sensitization method are described in, for example, chloroauric acid, potassium chloroaurate, potassium aurithiocyanate, gold sulfide, gold selenide, or US Pat. No. 2448060, British Patent No. 618061 and the like. The compound can be preferably used. Specific compounds for the reduction sensitization method include, for example, stannous chloride, aminoiminomethanesulfinic acid, hydrazine derivatives, borane compounds, silane compounds, polyamine compounds and the like in addition to ascorbic acid and thiourea dioxide. it can. Also, the pH of the emulsion should be 7 or more or pAg
Can be sensitized by reduction by aging while maintaining the value of 8.3 or less. Further, reduction sensitization can be performed by introducing a single addition portion of silver ions during grain formation.

The photosensitive silver halide of the present invention is used in an amount of 0.00 photosensitive silver halide per mol of the organic silver salt.
The amount is preferably 1 mol or more and 0.5 mol or less, more preferably 0.02 mol or more and 0.3 mol or less, and particularly preferably 0.03 mol or more and 0.25 mol or less. Regarding the mixing method and mixing conditions of the separately prepared photosensitive silver halide and organic silver salt, the prepared silver halide grains and organic silver salt are mixed with a high-speed stirrer, a ball mill, a sand mill, a colloid mill, a vibration mill, a homogenizer, etc. Or a method of preparing an organic silver salt by mixing the photosensitive silver halide prepared at any timing during the preparation of the organic silver salt, but the effect of the present invention is sufficient. There is no particular limitation as long as it appears.

Organic silver salts usable in the present invention are
Relatively stable to light, but forms a silver image when heated to 80 ° C. or higher in the presence of an exposed photocatalyst (such as a latent image of photosensitive silver halide) and a reducing agent It is a silver salt. The organic silver salt can be any organic substance including a source capable of reducing silver ions. Silver salts of organic acids, especially (C10-C30, preferably 15-28
Silver salts of long chain fatty carboxylic acids are preferred. Also preferred are organic or inorganic silver salt complexes in which the ligand has a complex stability constant in the range of 4.0 to 10.0. The silver-providing substance can preferably constitute about 5 to 30% by weight of the image forming layer. Preferred organic silver salts include silver salts of organic compounds having a carboxy group. Examples of these include, but are not limited to, silver salts of aliphatic carboxylic acids and silver salts of aromatic carboxylic acids. Preferred examples of the silver salt of an aliphatic carboxylic acid include silver behenate, silver stearate, silver oleate, silver laurate, silver caproate, silver myristate,
It includes silver palmitate, silver maleate, silver fumarate, silver tartrate, silver linoleate, silver butyrate and silver camphorate, mixtures thereof and the like.

Silver salts of compounds containing a mercapto group or a thione group and their derivatives can also be used.
Preferred examples of these compounds include silver salts of 3-mercapto-4-phenyl-1,2,4-triazole,
-Silver salt of mercaptobenzimidazole, silver salt of 2-mercapto-5-aminothiadiazole, silver salt of 2- (ethylglycolamido) benzothiazole, S-alkylthioglycolic acid (wherein the alkyl group has 12 carbon atoms).
~ 22) silver salt of thioglycolic acid, such as
Silver salt of dithiocarboxylic acid such as silver salt of dithioacetic acid, silver salt of thioamide, silver salt of 5-carboxyl-1-methyl-2-phenyl-4-thiopyridine, silver salt of mercaptotriazine, and silver salt of 2-mercaptobenzoxazole Silver salt,
Silver salts described in U.S. Pat. No. 4,123,274, such as 3-
Silver salts of 1,2,4-mercaptothiazole derivatives such as amino-5-benzylthio-1,2,4-thiazole silver salts, 3- (3- described in U.S. Pat. No. 3,301,768.
Carboxyethyl) -4-methyl-4-thiazoline-2
-Including silver salts of thione compounds such as silver salts of thione. Furthermore, compounds containing imino groups can be used. Preferred examples of these compounds include silver salts of benzotriazole and derivatives thereof, for example, silver salts of benzotriazole such as silver methylbenzotriazole, silver salts of halogen-substituted benzotriazole such as silver 5-chlorobenzotriazole, and US Pat. And silver salts of 1,2,4-triazole or 1-H-tetrazole as described in JP-A-4220709, silver salts of imidazole and imidazole derivatives, and the like. For example, US Pat. No. 4,761,361.
And various silver acetylide compounds as described in U.S. Pat. No. 4,775,613.

The shape of the organic silver salt that can be used in the present invention is not particularly limited, but needle crystals having a short axis and a long axis are preferable. As is well known in the light-sensitive silver halide light-sensitive material, the inversely proportional relationship between the size of silver salt crystal grains and the covering power is also established in the heat-developable light-sensitive material of the present invention. It is necessary to reduce the size of the organic silver salt, because a large organic silver salt particle in the image forming portion means a small covering power and a low image density. In the present invention, the minor axis 0.
It is preferably from 01 μm to 0.20 μm, the major axis is from 0.10 μm to 5.0 μm, and the minor axis is from 0.01 μm to 0.1 μm.
15 μm or less, more preferably 0.10 μm or more and 4.0 μm or less on the major axis. The particle size distribution of the organic silver salt is preferably monodispersed. Monodispersion means the percentage of the value obtained by dividing the standard deviation of the lengths of the minor axis and major axis by the minor axis and major axis, respectively, is preferably 100% or less, more preferably 80% or less, and even more preferably 50% or less. It is. The shape of the organic silver salt can be measured from a transmission electron microscope image of the organic silver salt dispersion. As another method for measuring the monodispersity, there is a method of obtaining the standard deviation of the volume-weighted average diameter of the organic silver salt, and the percentage variation coefficient of the value divided by the volume-weighted average diameter is preferably 100% or less, more preferably It is 80% or less, more preferably 50% or less. As a measuring method, for example, an organic silver salt dispersed in a liquid is irradiated with a laser beam, and the autocorrelation coefficient with respect to the time change of the fluctuation of the scattered light is obtained from the particle size (volume weight average diameter) obtained. be able to.

Silver halide emulsion and / or in the present invention
Alternatively, the organic silver salt may be further protected against the formation of additional fog and stabilized against reduced sensitivity during inventory storage by antifoggants, stabilizers and stabilizer precursors. Suitable antifoggants, stabilizers and stabilizer precursors, which may be used alone or in combination, are described in US Pat.
Thiazonium salts described in US Pat. No. 94,716, US Pat. No. 28
Azaindenes described in U.S. Pat. Nos. 2,864,637 and 2,444,605; mercury salts described in U.S. Pat. No. 2,728,663; urazoles described in U.S. Pat. No. 3,287,135;
Sulfocatechols described in U.S. Pat. No. 3,235,652, oximes, nitrones, nitroindazoles, U.S. Pat. No. 2,839,405 described in British Patent No. 623,448.
Polyvalent metal salts described in US Pat. No. 3220839, thiuronium salts described in US Pat. No. 3220839, and US Pat. No. 25662.
63 and 2579915, palladium, platinum and gold salts, US Pat. Nos. 4,108,665 and 4,442,202, halogen-substituted organic compounds, US Pat. Nos. 4,128,557 and 41370.
79, 4138365 and 445935.
No. 0 and the triazines described in US Pat.
There are phosphorus compounds described in No. 85 and the like.

In the light-sensitive emulsion layer of the present invention, polyhydric alcohols (for example, glycerin and diols of the type described in US Pat. No. 2,960,404), plasticizers and lubricants, US Pat. Nos. 2,588,765 and 3,121060 are used. The fatty acids or esters described in JP-A No. 955061 and the silicone resins described in British Patent No. 955061 can be used.

A hardener may be used in each of the layers such as the photosensitive emulsion layer, the protective layer and the back layer of the present invention. Examples of the hardener include U.S. Pat. No. 4,281,060 and JP-A-6-2081.
For example, polyisocyanates described in JP-A-93-93, epoxy compounds described in U.S. Pat. No. 4,791,042, and vinylsulfone-based compounds described in JP-A-62-89048 can be used.

In the present invention, a surfactant may be used for the purpose of improving coatability and charging. As the surfactant, any surfactant such as nonionic, anionic, cationic, and fluorine can be used as appropriate. Specifically, fluorine polymer surfactants described in JP-A-62-170950, U.S. Pat. No. 5,382,504, and the like;
No. 44945, JP-A-63-188135, etc., fluorine surfactants described in U.S. Pat. No. 3,885,965, etc., polysiloxane acid surfactants described in U.S. Pat.
And polyalkylene oxides and anionic surfactants described in No. 1140 and the like.

The sensitizing dye in the present invention may be any one as long as it can spectrally sensitize silver halide grains in a desired wavelength region when adsorbed on silver halide grains.

As the sensitizing dye, cyanine dye, merocyanine dye, complex cyanine dye, complex merocyanine dye, holoholer cyanine dye, styryl dye, hemicyanine dye, oxonol dye, hemioxonol dye and the like can be used.

Useful sensitizing dyes used in the present invention are described in, for example, RESEARCH DISCLOSURE Item 17643IV-A (December 1978).
p.23), and Item 1831X (P.437, August 1979) of the same item, or in the literature cited.

In particular, a sensitizing dye having a spectral sensitivity suitable for the spectral characteristics of the light source of various laser imagers, scanners, imagesetters and plate-making cameras can be advantageously selected.

As an example of spectral sensitization to red light, He-
Japanese Patent Laid-Open No. 54-18726 discloses a Ne laser light source.
Compounds I-1 to I-38 described in JP-A-6-7
Compounds I-1 to I-35 described in JP-A-5322 and I-1 to I-34 described in JP-A-7-287338.
JP-B-55-3981 for the compound and LED light source
Dyes 1 to 20 described in JP-A-62-28434
Compounds I-1 to I-37 described in No. 3 and compounds I-1 to I-34 described in JP-A-7-287338 are advantageously selected.

The silver halide grains are spectrally sensitized in any wavelength range from 750 to 1400 nm. Specifically, a photosensitive silver halide is replaced with cyanine, merocyanine,
A variety of known dyes, including styryl, hemicyanine, oxonol, hemioxonol and xanthene dyes, can be spectrally advantageously sensitized. Useful cyanine dyes are, for example, cyanine dyes having basic nuclei such as thiazoline nuclei, oxazoline nuclei, pyrroline nuclei, pyridine nuclei, oxazole nuclei, thiazole nuclei, selenazole nuclei and imidazole nuclei. Preferred useful merocyanine dyes are, in addition to the basic nucleus described above, a thiohydantoin nucleus, a rhodanine nucleus, an oxazolidinedione nucleus, a thiazolinedione nucleus, a barbituric acid nucleus,
It also includes acidic nuclei such as thiazolinone nuclei, malononitrile nuclei and pyrazolone nuclei. Among the above cyanine and merocyanine dyes, those having an imino group or a carboxyl group are particularly effective. For example, US Pat. No. 3,761,
No. 279, No. 3719495, No. 3877943
No., British Patent Nos. 1466201 and 1469117
No. 14222057, Japanese Examined Patent Publication No. 3-10391,
JP-B-6-52387, JP-A-5-341432,
It may be appropriately selected from known dyes described in JP-A-6-194781 and JP-A-6-301141. A particularly preferable dye structure is a cyanine dye having a thioether bond.
2-58239, 3-138638, 3-13
No. 8642, No. 4-255840, No. 5-72659
No. 5, No. 5-72661, No. 6-222491, No. 2
-230506, 6-258757, 6-31
No. 7868, No. 6-324425, Tokuyohei 7-500
The cyanine dyes described in No. 926 are mentioned.

These sensitizing dyes may be used alone or in combination thereof, and the combination of sensitizing dyes is often used particularly for the purpose of supersensitization. Along with the sensitizing dye, the emulsion may contain a dye which does not itself have a spectral sensitizing effect or a substance which does not substantially absorb visible light and exhibits supersensitization.

Useful sensitizing dyes, combinations of dyes exhibiting supersensitization and substances exhibiting supersensitization are described in Research Disclosure 176, 17643 (December 1978).
Monthly) Page 23, IV, Section J, or the aforementioned Tokubo Sho 49-2
5500, 43-4933, JP-A-59-19032
And No. 59-192242.

The sensitizing dyes used in the present invention may be used in combination of two or more kinds. To add sensitizing dyes to a silver halide emulsion, they may be directly dispersed in the emulsion,
Or water, methanol, ethanol, propanol,
Acetone, methyl cellosolve, 2,2,3,3-tetrafluoropropanol, 2,2,2-trifluoroethanol, 3-methoxy-1-propanol, 3-methoxy-1-butanol, 1-methoxy-2-propanol , N, N-dimethylformamide, etc. may be added to the emulsion by dissolving them in a single solvent or in a mixed solvent.

Further, as disclosed in US Pat. No. 3,469,987, etc., a dye is dissolved in a volatile organic solvent, this solution is dispersed in water or a hydrophilic colloid, and this dispersion is used as an emulsion. Method of adding to the inside, Japanese Patent Publication No.44-
23389, 44-25555, 57-220.
As disclosed in No. 91, etc., the dye is dissolved in an acid,
A method in which this solution is added to an emulsion or an aqueous solution is added to the emulsion in the presence of an acid or a base, US Pat.
A method of adding an aqueous solution or colloidal dispersion in the presence of a surfactant to the emulsion as disclosed in, for example, No. 822135 and No. 4006025.
As disclosed in JP-A-53-102733 and JP-A-58-105141, a method in which a dye is directly dispersed in a hydrophilic colloid and the dispersion is added to an emulsion is disclosed in JP-A-51-74624. As disclosed, it is also possible to use a method in which a dye is dissolved using a red-shifting compound and this solution is added to the emulsion. Also, ultrasonic waves can be used for the solution.

The sensitizing dye used in the present invention may be added to the silver halide emulsion of the present invention at any step in the preparation of emulsions which has heretofore been found to be useful. For example, US Pat. Nos. 2,735,766 and 3635.
No. 28960, No. 4183756, No. 42256
66, JP-A-58-184142 and 60-196.
No. 749, etc., the period before the grain formation step and / or desalting of the silver halide, the period during the desilvering step and / or after the desalination to the start of chemical ripening, As disclosed in the specification of JP-A-58-113920 and the like, immediately before or during the chemical ripening, at any time and after the chemical ripening and before the coating until the emulsion is coated. May be added at.
Also, U.S. Pat. No. 4,225,666 and JP-A-58-76.
29, etc., the same compound alone or in combination with a compound having a different structure, for example, divided into a grain formation step and a chemical ripening step or after chemical ripening, The compound may be added in divided portions, such as before aging or during the process and after completion, or the compound and the combination of compounds may be added in different types.

The reducing agent for the organic silver salt may be any substance that reduces silver ions to metallic silver, preferably an organic substance. Conventional photographic developers such as phenidone, hydroquinone and catechol are useful, but hindered phenol reducing agents are preferred. The reducing agent is used in one of the image forming layers.
It should be present as .about.10% by weight. When a reducing agent is added to a layer other than the emulsion layer in a multilayer structure,
A slightly higher percentage, about 2-15% by weight, tends to be more desirable.

A wide range of reducing agents have been disclosed in the photothermographic materials utilizing organic silver salts. For example, amidoximes such as phenylamidoxime, 2-thienylamidooxime and p-phenoxyphenylamidooxime; azines such as 4-hydroxy3,5-dimethoxybenzaldehyde azine; 2,2'-bis (hydroxymethyl) propionyl-. A combination of an aliphatic carboxylic acid arylhydroazide and ascorbic acid, such as a combination of β-phenylhydrazine and ascorbic acid;
Combination of polyhydroxybenzene and hydroxylamine, reductone and / or hydrazine (eg combination of hydroquinone and bis (ethoxyethyl) hydroxylamine, piperidinohexose reductone or formyl-4-methylphenylhydrazine); Phenylhydroxam Acids, hydroxamic acids such as p-hydroxyphenylhydroxamic acid and β-anilinehydroxamic acid; combinations of azines with sulfonamide phenols (eg, phenothiazine and 2,6-dichloro-4-).
Benzenesulfonamidophenol, etc.); Ethyl-α
-Cyano-2-methylphenylacetate, ethyl-α
Α-cyanophenylacetic acid derivatives such as cyanophenylacetate; 2,2′-dihydroxy-1,1′-binaphthyl, 6,6′-dibromo-2,2′-dihydroxy-1,1′-binaphthyl and bis ( 2-hydroxy-
Bis-β-naphthol as exemplified by 1-naphthyl) methane; bis-β-naphthol and a 1,3-dihydroxybenzene derivative (for example, 2,4-dihydroxybenzophenone or 2 ′, 4′-dihydroxyacetophenone) A combination of 3-methyl-1-phenyl-5-
5-pyrazolones, such as pyrazolones; reductones as exemplified by dimethylaminohexose reductone, anhydrodihydroaminohexose reductone and anhydrodihydropiperidone hexose reductone;
Sulfonamidophenol reducing agents such as 2,6-dichloro-4-benzenesulfonamidophenol and p-benzenesulfonamidophenol; 2-phenylindane-1,3-dione and the like; 2,2-dimethyl-7-t
Chromans such as -butyl-6-hydroxychroman;
2,6-dimethoxy-3,5-dicarbethoxy-1,
1,4-dihydropyridines such as 4-dihydropyridine; bisphenols (for example, bis (2-hydroxy-
3-t-butyl-5-methylphenyl) methane, 2,2
-Bis (4-hydroxy-3-methylphenyl) propane, 4,4-ethylidene-bis (2-t-butyl-6-
Methylphenol), 1,1-bis (2-hydroxy-
3,5-dimethylphenyl) -3,5,5-trimethylhexane and 2,2-bis (3,5-dimethyl-4-)
Hydroxyphenyl) propane etc.); ascorbic acid derivatives (eg 1-ascorbyl palmitate, ascorbyl stearate etc.); and aldehydes and ketones such as benzyl and biacetyl; 3-pyrazolidone and certain indane-1,3-diones etc. There is.

Although not required to practice the invention,
It may be advantageous to add a mercury (II) salt as an antifoggant to the emulsion layer. Preferred mercury (II) salts for this purpose are mercury acetate and mercury bromide. The photosensitive silver halide used in the present invention generally has an organic silver salt content of 0.75 to
It can be used in the range of 25 mol%, preferably 2 to 20 mol%.

In the present invention, a mercapto compound, a disulfide compound or a thione compound is contained for the purpose of suppressing or accelerating the development to control the development, improving the spectral sensitization efficiency, and improving the storage stability before and after the development. be able to.

When the mercapto compound is used in the present invention, it may have any structure, but Ar-SM, Ar
Those represented by -SS-Ar are preferred. In the formula, M is a hydrogen atom or an alkali metal atom, and Ar is an aromatic ring or a condensed aromatic ring having one or more nitrogen, sulfur, oxygen, selenium or tellurium atoms. Preferably, the heteroaromatic ring is benzimidazole, naphthimidazole, benzothiazole, naphthothiazole, benzoxazole, naphthoxazole, benzoselenazole, benzoterzole, imidazole, oxazole,
Pyrazole, triazole, thiadiazole, tetrazole, triazine, pyrimidine, pyridazine, pyrazine, pyridine, purine, quinoline or quinazolinone. This heteroaromatic ring is, for example, a halogen (for example,
Br and Cl), hydroxy, amino, carboxy,
Alkyl (eg one or more carbon atoms, preferably 1
May also have a substituent selected from the group consisting of those having from 1 to 4 carbon atoms) and alkoxy (e.g., having at least one carbon atom, preferably having from 1 to 4 carbon atoms). Good. Examples of the mercapto-substituted heteroaromatic compound include 2-mercaptobenzimidazole, 2-mercaptobenzoxazole, 2-mercaptobenzothiazole, 2-mercapto-5-methylbenzimidazole, 6-ethoxy-2-mercaptobenzothiazole, 2'-dithiobis-benzothiazole, 3-mercapto-1,2,4-triazole, 4,5-diphenyl-2-imidazolethiol, 2-mercaptoimidazole, 1-ethyl-2-mercaptobenzimidazole, 2-mercaptoquinoline , 8-mercaptopurine, 2-mercapto-4 (3H) -quinazolinone, 7-
Trifluoromethyl-4-quinolinethiol, 2,3
5,6-tetrachloro-4-pyridinethiol, 4-amino-6-hydroxy-2-mercaptopyrimidine monohydrate, 2-amino-5-mercapto-1,3,4
-Thiadiazole, 3-amino-5-mercapto-1,
2,4-triazole, 4-hydroxy-2-mercaptopyrimidine, 2-mercaptopyrimidine, 4,6-diamino-2-mercaptopyrimidine, 2-mercapto-
Examples include 4-methylpyrimidine hydrochloride, 3-mercapto-5-phenyl-1,2,4-triazole, 2-mercapto-4-phenyloxazole, and the like, but the invention is not limited thereto.

The addition amount of these mercapto compounds is preferably in the range of 0.001 to 1.0 mol per mol of silver in the emulsion layer, and more preferably 0.01 to 0.3 mol per mol of silver. Is the amount of.

The hydrazine derivative used in the present invention will be described. The compound of the general formula (I) described in Japanese Patent Application No. 6-47961 is used in the present invention. Specifically, compounds represented by I-1 to I-53 described in the same specification are used.

The following hydrazine derivatives are also preferably used.

The compounds represented by (Chemical Formula 1) described in JP-B-6-77138, specifically the compounds described on pages 3 and 4 of the publication. Compounds represented by the general formula (I) described in JP-B-6-93082, specifically,
38 compounds. General formula (4) described in JP-A-6-230497,
Compounds represented by the general formula (5) and the general formula (6), specifically, Compounds 4-1 to 4-
10, compounds 5-1 to 5-42, and 39 described on pages 28 to 36
Page 6-1 to compound 6-7 to compound 6-7. JP 6-28
Compounds represented by the general formula (1) and general formula (2) described in No. 9520, specifically the compounds described on pages 5 to 7 of the publication.
1-1) to 1-17) and 2-1). Compounds represented by (Chemical Formula 2) and (Chemical Formula 3) described in JP-A-6-313936, specifically, compounds described on pages 6 to 19 of the same publication. Compounds represented by (Chemical Formula 1) described in JP-A-6-313951, specifically, compounds described on pages 3 to 5 of the same. Compounds represented by formula (I) described in JP-A-7-5610, specifically compounds I-1 to I-38 described on pages 5 to 10 of the same; Compounds represented by formula (II) described in JP-A-7-77783, specifically, compounds II-1 to II-102 described on pages 10 to 27 of the same publication. JP 7-10
Compounds represented by the general formula (H) and general formula (Ha) described in No. 4426, specifically the compounds described on pages 8 to 15 of the publication.
H-1 to H-44. A compound characterized by having an anionic group or a nonionic group forming an intramolecular hydrogen bond with a hydrogen atom of hydrazine in the vicinity of the hydrazine group described in Japanese Patent Application No. 7-191007, especially the general formula (A) , General formula (B), general formula
(C), the general formula (D), the general formula (E), a compound represented by the general formula (F), specifically the compounds N-1 to N-3 described in the publication.
0. Compounds represented by the general formula (1) described in Japanese Patent Application No. 7-191007, specifically Compounds D-1 to D-55 described in the same publication.

The hydrazine nucleating agent of the present invention is a suitable water-miscible organic solvent such as alcohols (methanol, ethanol, propanol, fluorinated alcohol), ketones (acetone, methyl ethyl ketone), dimethylformamide, dimethyl sulfoxide, It can be used by dissolving it in methyl cellosolve or the like.

Also, by a well-known emulsification and dispersion method, an oil such as dibutyl phthalate, tricresyl phosphate, glyceryl triacetate or diethyl phthalate, or an auxiliary solvent such as ethyl acetate or cyclohexanone is used to dissolve and dissolve. An emulsified dispersion can be prepared and used. Alternatively, a powder of a hydrazine derivative can be dispersed in water by a ball mill, a colloid mill, or an ultrasonic wave by a method known as a solid dispersion method and used.

The hydrazine nucleating agent of the present invention may be added to any layer of the silver halide emulsion layer on the silver halide emulsion layer side of the support or another hydrophilic colloid layer.
It is preferably added to the silver halide emulsion layer or the hydrophilic colloid layer adjacent thereto.

The addition amount of the nucleating agent of the present invention is preferably 1 μmol to 10 mmol, more preferably 10 μmol to 5 mmol, and most preferably 20 μmol to 5 mmol with respect to 1 mol of silver halide.

The photographic emulsion for heat development in the present invention can be coated on various supports. Typical supports include polyester films, primed polyester films, poly (ethylene terephthalate) films, polyethylene naphthalate films, cellulose nitrate films, cellulose ester films, poly (vinyl acetal) films, polycarbonate films and related or resinous Materials, as well as glass.
Preferably, the support is transparent.

The photothermographic material of the present invention comprises an antistatic or conductive layer such as a soluble salt (eg, chloride, nitrate, etc.), a vapor-deposited metal layer, as described in US Pat. Nos. 2861056 and 3206312. A ionic polymer or a layer containing an insoluble inorganic salt as described in US Pat. No. 3,428,451, or the like.

As a method for obtaining a color image using the photothermographic material of the present invention, there is a method described in JP-A No. 7-13295, page 10, left column, line 43 to page 11, left column, line 40. Examples of color dye image stabilizers include British Patent No. 1,326,889, U.S. Patent Nos. 3,432,300, 3,699,909, 3,574,627 and 357.
Nos. 3050, 3764337 and 4042
No. 394.

The photothermographic emulsions of this invention can be coated by a variety of coating operations including dip coating, air knife coating, flow coating or extrusion coating using a hopper of the type described in US Pat. No. 2,681,294. If desired, US Pat. No. 2,761,791 and British Patent No. 83
Two or more layers can be coated simultaneously by the method described in US Pat.

An additional layer in the photothermographic material of the invention,
For example, it can include a dye-receiving layer for receiving a mobile dye image, an opacifying layer if reflective printing is desired, a protective topcoat layer, and a primer layer known in the photothermographic art. The light-sensitive material of the present invention is the light-sensitive material 1
It is preferable that an image can be formed on only one sheet, and it is preferable that a functional layer such as an image receiving layer necessary for image formation does not become another member.

The photothermographic material of the invention may be provided with a surface protective layer for the purpose of preventing adhesion of the image forming layer.
Any anti-adhesion material may be used as the surface protective layer. Examples of anti-adhesion materials include waxes, silica particles, styrene-containing elastomeric block copolymers (eg, styrene-butadiene-styrene, styrene-isoprene-styrene), cellulose acetate, cellulose acetate butyrate, cellulose propionate, and the like. And mixtures.

Matting agents such as starch, titanium dioxide, zinc oxide, silica, beads of the type described in US Pat. Nos. 2,992,101 and 2,701,245 are used in the emulsion layer or protective layer of the emulsion layer in the present invention. It may contain polymer beads, etc. The matte degree of the emulsion surface may be any value as long as stardust failure does not occur, but the Beck smoothness is preferably 500 seconds or more and 10,000 seconds or less, and particularly preferably 1000 seconds or more and 10,000 seconds or less.

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

In addition to the components described above, it may be advantageous to include additives known as "toning agents" to improve the image. For example, the toning material is 0.1% of the total silver holding component.
It may be present in an amount of from 10% by weight. Toning agents are materials well known in the photographic art, as shown in U.S. Pat. Nos. 3,080,254, 3,847,612 and 4,123,282.

Examples of toning agents are phthalimide and N-hydroxyphthalimide; succinimide, pyrazoline-
5-one, and quinazolinone, 3-phenyl-2-
Cyclic imides such as pyrazolin-5-one, 1-phenylurazole, quinazoline and 2,4-thiazolidinedione; naphthalimides (e.g. N-hydroxy-
1,8-naphthalimide); cobalt complex (for example, cobalt hexamine trifluoroacetate); 3-mercapto-1,2,4-triazole, 2,4-dimercaptopyrimidine, 3-mercapto-4,5-diphenyl- Mercaptans exemplified by 1,2,4-triazole and 2,5-dimercapto-1,3,4-thiadiazole; N- (aminomethyl) aryldicarboximide [eg, (N, N-dimethylaminomethyl) phthalimide And N, N- (dimethylaminomethyl) -naphthalene-2,3-dicarboximide); and blocked pyrazoles, isothiuronium derivatives and certain photobleaching agents (eg N, N'-hexamethylenebis (1- Carbamoyl-3,5-dimethylpyrazole),
1,8- (3,6-diazaoctane) bis (isothiuronium trifluoroacetate) and 2-tribromomethylsulfonyl)-(benzothiazole)]; and 3-ethyl-5 [(3-ethyl-2-benzo Thiazolinylidene) -1-methylethylidene] -2-thio-2,
4-oxazolidinedione; phthalazinone, phthalazinone derivative or metal salt, or 4- (1-naphthyl)
Phthalazinone, 6-chlorophthalazinone, 5,7-dimethoxyphthalazinone and 2,3-dihydro-1,4-
Derivatives such as phthalazinedione; phthalazinone and phthalic acid derivatives (eg, phthalic acid, 4-methylphthalic acid, 4
-Nitrophthalic acid and tetrachlorophthalic anhydride, etc.); phthalazine, phthalazine derivatives or metal salts, or 4- (1-naphthyl) phthalazine, 6
-Derivatives such as chlorophthalazine, 5,7-dimethoxyphthalazine and 2,3-dihydrophthalazine; phthalazine and phthalic acid derivatives (eg phthalic acid, 4-methylphthalic acid, 4-nitrophthalic acid and tetrachlorophthalic anhydride) Etc.); quinazolinediones, benzoxazine or naphthoxazine derivatives; rhodium complexes that function not only as toning agents but also as a source of halide ions for silver halide formation in situ, eg hexachlororhodium (III) Ammonium acid, rhodium bromide, rhodium nitrate and hexachlororhodium (II
I) Potassium acid and the like; inorganic peroxides and persulfates, such as ammonium disulfide and hydrogen peroxide;
Benzoxazines such as 1,3-benzoxazine-2,4-dione, 8-methyl-1,3-benzoxazine-2,4-dione and 6-nitro-1,3-benzoxazine-2,4-dione -2,4-dione; pyrimidine and asymmetric-triazine (for example, 2,4-dihydroxypyrimidine, 2-hydroxy-4-aminopyrimidine, etc.), azauracil, and tetraazapentalene derivative (for example, 3,6-dimercapto) -1,4-diphenyl-1H, 4H-2,3a, 5,6a-tetraazapentalene, and 1,4-di (o-chlorophenyl)
-3,6-dimercapto-1H, 4H-2,3a, 5
6a-tetraazapentalene) and the like.

The heat-developable light-sensitive material of the present invention has a photosensitive layer containing at least one silver halide emulsion on one side of the support and a back layer on the other side, as described above. It is preferably a single-sided photosensitive material.

In the present invention, a matting agent may be added to the single-sided light-sensitive material in order to improve transportability. The matting agent is generally fine particles of an organic or inorganic compound insoluble in water. As the matting agent, any matting agent can be used. For example, U.S. Pat. Nos. 1,939,213, 2,701,245, 2,322,037, 3,226,672, and 3
Organic matting agents described in the respective specifications, such as 593344 and 376,448, 1260772, 21st
No. 92241, No. 3257206, No. 33709
Inorganic matting agents well-known in the art such as inorganic matting agents described in the respective specifications such as No. 51, No. 3523022, and No. 3769020 can be used. For example, specifically, examples of organic compounds that can be used as a matting agent include, as examples of water-dispersible vinyl polymers, polymethyl acrylate, polymethyl methacrylate, polyacrylonitrile, acrylonitrile-α-methylstyrene copolymer, and polystyrene. , Styrene-divinylbenzene copolymer, polyvinyl acetate, polyethylene carbonate, polytetrafluoroethylene, etc., examples of cellulose derivatives such as methylcellulose, cellulose acetate, cellulose acetate propionate, etc., and starch derivatives such as carboxy starch, carboxynitrophenyl Starch, urea-formaldehyde-starch reactants, etc.
Gelatin hardened with a known hardener, hardened gelatin obtained by coacervate hardening to form hollow microcapsules, and the like can be preferably used. Examples of inorganic compounds include silicon dioxide, titanium dioxide, magnesium dioxide,
Aluminum oxide, barium sulfate, calcium carbonate, silver chloride desensitized by a known method, silver bromide, glass, diatomaceous earth and the like can be preferably used. The above matting agents can be used by mixing different types of substances as necessary. The size and shape of the matting agent are not particularly limited, and those having an arbitrary particle size can be used. In practicing the present invention, it is preferable to use one having a particle size of 0.1 μm to 30 μm. The particle size distribution of the matting agent may be narrow or wide. On the other hand, the matting agent is the haze of the photosensitive material,
Since it greatly affects the surface gloss, it is preferable that the particle size, the shape, and the particle size distribution are brought into a required state at the time of preparing the matting agent or by mixing a plurality of matting agents.

In the present invention, the Becks smoothness of the back layer is preferably 250 seconds or less and 10 seconds or more,
More preferably, it is 180 seconds or less and 50 seconds or more.

In the present invention, the matting agent is preferably contained in the outermost surface layer of the light-sensitive material, a layer functioning as the outermost surface layer, or a layer close to the outer surface, and a layer acting as a so-called protective layer. It is preferably contained.

Suitable binders for the back layer in the present invention are transparent or translucent, generally colorless, and include natural polymers such as synthetic resins, polymers and copolymers, and other film-forming media such as: gelatin, gum arabic, poly (vinyl). Alcohol), hydroxyethyl cellulose, cellulose acetate, cellulose acetate butyrate, poly (vinylpyrrolidone), casein, starch, poly (acrylic acid), poly (methylmethacrylic acid), poly (vinyl chloride), poly (methacrylic acid), copoly (Styrene-maleic anhydride), copoly (styrene-acrylonitrile), copoly (styrene-butadiene), poly (vinyl acetal) s [eg poly (vinyl formal) and poly (vinyl butyral)],
Poly (ester) s, poly (urethanes), phenoxy resin, poly (vinylidene chloride), poly (epoxide)
, Poly (carbonate) s, poly (vinyl acetate), cellulose esters, and poly (amide) s. The binder may be coated from water or an organic solvent or emulsion.

In the present invention, the back layer is 750 to 14
The maximum absorption in the range of 00 nm is preferably 0.05 or more and 2 or less, more preferably 0.2 or more and 2 or less infrared absorption, and the absorption in the visible region is 0.0 or less.
It is preferably from 01 to less than 0.5, more preferably an antihalation layer having an optical density of from 0.001 to less than 0.3.

When the antihalation dye is used in the present invention, the dye has a desired absorption in the range of 750 to 1400 nm, has a sufficiently small absorption in the visible region, and has a preferable absorbance spectrum shape of the back layer. Any compound may be used. For example, compounds described in JP-A-7-13295 and U.S. Pat. No. 5,380,635;
No. 8539, page 13, lower left column, line 1 to page 14, lower left column, line 9; and JP-A-3-24539, page 14, lower left column to page 16, lower right column, compounds described in The invention is not limited to these.

US Pat. Nos. 4,460,681 and 4,
Backside resistive heating layer (bac
kside resistive heatinng layer) can also be used in the photothermographic image system.

[0135]

The present invention will be specifically described below with reference to examples.

Example 1 <Preparation of silver halide grains> 22 g of phthalated gelatin and 30 mg of potassium bromide were dissolved in 700 ml of water and the temperature was adjusted to 3
After adjusting the pH to 5.0 at 5 ° C., 159 ml of an aqueous solution containing 18.6 g of silver nitrate and 9 parts of potassium bromide and potassium iodide were added.
An aqueous solution containing a molar ratio of 2: 8 was added by a control double jet method over 10 minutes while maintaining the pAg at 7.7. Then, 476 ml of an aqueous solution containing 55.4 g of silver nitrate, 12 μmol / l of dipotassium hexachloroiridate and 1 mol / l of potassium bromide at an pAg of 7.7 was maintained for 30 minutes by the control double jet method. Added. After that, the pH is lowered, the precipitate is aggregated and precipitated, desalted, and 0.1 g of phenoxyethanol is added to adjust the pH to 5.9.
Silver iodobromide grains adjusted to pAg 8.2 (iodine content core 8 mol%, average 2 mol%, average size 0.05 μm, projected area variation coefficient 8%, (100) plane ratio 88% cubic grains)
Was completed.

The halogenated particles thus obtained were heated to 60 ° C., and 85 μmol of sodium thiosulfate and 11 μmol and 15 μmol of 2,3,4,5,6-pentafluorophenyldiphenylphosphine selenide were added per mol of silver. Molar tellurium compound 1, chloroauric acid 3.5 μmol, thiocyanic acid 2
75 μmol was added, the mixture was aged for 120 minutes and then rapidly cooled to 30 ° C. to obtain a silver halide emulsion.

<Preparation of Organic Acid Silver Emulsion> Stearic acid 1.
3 g, 0.5 g of arachidic acid, 8.5 g of behenic acid and 300 ml of distilled water were mixed at 90 ° C. for 15 minutes, 31.1 ml of a 1N aqueous solution of NaOH was added over 15 minutes with vigorous stirring, and the temperature was lowered to 30 ° C. did. Next, 7 ml of a 1N-phosphoric acid aqueous solution was added, and 0.01 g of N-bromosuccinimide was added with vigorous stirring, and then the silver halide grains prepared in advance were adjusted so that the silver halide amount became 1.25 mmol. Was added to. Further, 25 ml of 1N-silver nitrate aqueous solution was added over 2 minutes, and stirring was continued for 90 minutes. Thereafter, the solid content was separated by suction filtration, and the solid content was washed with water until the conductivity of the filtrate became 30 μS / cm. 37 g of a 1.2% by weight solution of polyvinyl acetate in butyl acetate was added to the solid content thus obtained, and the mixture was stirred. The stirring was stopped and the mixture was allowed to stand to separate into an oil layer and an aqueous layer. Was. Next, polyvinyl butyral (Denka Butyral # 3000-K manufactured by Denki Kagaku Kogyo KK) was added to the oil layer.
20 g of a 5 wt% 2-butanone solution was added and stirred. Furthermore, after adding 0.1 mmol of pyridinium perbromide and 0.16 mmol of calcium bromide dihydrate together with 0.7 g of methanol, 40 g of 2-butanone and polyvinyl butyral (PVB B-76 manufactured by Monsanto Co.) were added. 8 g was added and dispersed by a homogenizer to obtain an organic acid silver salt emulsion (acicular particles having an average particle size of 0.04 μm, an average major axis of 1 μm and a coefficient of variation of 30%).

<Preparation of Emulsion Coating Solution> Each chemical was added to the organic acid silver emulsion obtained above in the following amount per mol of silver. Sodium phenylthiosulfonate 1 at 25 ° C
0 mg, 65 mg of dye 1, 30 mg of dye 2, 2-mercapto-5-methylbenzimidazole 2 g, 4-chlorobenzophenone-2-carboxylic acid 21.5 g, 2-butanone 580 g, and dimethylformamide 220 g were added with stirring. It was left for 3 hours. Then, 5-tribromomethylsulfonyl-2-methylthiadiazole 8 g, 2
-Tribromomethylsulfonylbenzothiazole 6g
, 4,6-ditrichloromethyl-2-phenyltriazine 5 g, disulfide compound 1 2 g, 1,1-bis (2-hydroxy-3,5-dimethylphenyl) -3,
5,5-Trimethylhexane 200 g, tetrachlorophthalic acid 5 g, Megafax F-176P (Dainippon Ink and Chemicals KK Fluorosurfactant) 1.1 g, 2
590 g of butanone and 10 g of methyl isobutyl ketone were added with stirring. Other dyes listed in Table 1 are listed in Table 1.
Was added in such an amount that the absorbance becomes. Further, 31 g of Byron 200 (polyester manufactured by Toyobo Co., Ltd.) was added.

<Emulsion side protective layer coating solution> CAB171-1
5S (cellulose acetate butyrate manufactured by Eastman Chemical Co., Ltd.) 75 g, 4-methylphthalic acid 5.7 g, tetrachlorophthalic anhydride 1.5 g, phthalazine 11 g, 0.3
g Megafax F-176P, Syldex H31
(Doikai Chemical Co., Ltd. spherical silica average size 3 μm) 2 g,
A solution was prepared by dissolving 6 g of sumidur N3500 (polyisocyanate manufactured by Sumitomo Bayer Urethane Co., Ltd.) in 3070 g of 2-butanone and 30 g of ethyl acetate.

<Back Surface Coating Solution> Calcium compound 1 was synthesized as follows. 0.08 mol of 3,5-di-te
167 ml of an aqueous solution containing 0.019 mol of calcium chloride and 125 ml of 25% aqueous ammonia were added to 1 liter of an ethanol solution containing rt-butylcatechol, and air was blown at room temperature for 3 hours to obtain bis [2- (3,5). -Ji-
tert-butyl-o-benzoquinonemonoimine) -4,6
[Di-tert-butylphenolato] calcium (II) crystals (calcium compound 1) were precipitated.

12 g of polyvinyl butyral (Denka Butyral # 4000-2 manufactured by Denki Kagaku Kogyo KK), C
AB381-20 ((Eastman Chemical Co., Ltd. cellulose acetate butyrate) 12 g, 30 mg of dye 1, 75 mg of calcium compound 1, 100 mg of dye 2, 5 mg of dye 3, Sildex H121 (Dokai Chemical Co., Ltd. Silica average size 12 μm) 0.4 g, Sildex H51
(Average size of true spherical silica manufactured by Dokai Chemical Co., Ltd. 5μm) 0.4
g, 0.1g Megafax F-176P, 2g su
Midur N3500 was added to 500 g of 2-butanone and 500 g of 2-propanol with stirring, and dissolved and mixed.

The emulsion layer coating solution prepared as described above was coated on a 175 μm polyethylene terephthalate support tinted with a blue dye so that the silver amount was 2.3 mg / m ^2, and then on the surface opposite to the emulsion layer. Back surface coating liquid to dry thickness 3
It was applied to have a thickness of μm. Further, an emulsion surface protective layer coating solution was applied on the emulsion surface to a dry thickness of 2 μm.
The smoothness of the thus obtained light-sensitive material (the Beck's smoothness was examined by using the Oken type smoothness measurement described in J. TAPPI Paper Pulp Test Method No. 5) was 1000 seconds for the emulsion side and 70 seconds for the back side.
Seconds.

However, in Comparative Samples 8 and 9, Dye 1 was added to the coating solution for the back surface to increase the absorbance of the back.

The tellurium compound 1, the disulfide compound 1, the dyes 1 and 2, and the dyes 1 to 3 used above are as shown below.

[0146]

Embedded image

The refractive indices of the support, the photosensitive emulsion layer, the back layer and the protective layer are 1.665, 1.654 and 1.663, respectively.
It was 1.672. The refractive index was determined using an Abbe refractometer using a sodium lamp.

Measurement of Absorbance After removing the back surface of the photosensitive material at the cell installation position of a spectrophotometer (U-3410: made by Hitachi), the photosensitive emulsion surface is directed toward the light source side (perpendicular to the incident light. ), The support was subtracted as a reference, and the absorbance at the exposure wavelength of 810 nm was measured. The light transmitted through the photosensitive material was captured by an integrating sphere (opening area: 20 mm × 15 mm) placed about 12 cm ahead and collected by a photomultiplier tube. The absorbance of the back layer was also measured according to the above.

Observation of interference fringes The light-sensitive material prepared above was uniformly exposed to light from the emulsion surface side of the light-sensitive material by exposing the light-sensitive material to laser light with an exposure machine using a semiconductor laser having a wavelength of 810 nm as an exposure source. A uniform image was formed with a subtracted optical density value of about 1.0. At this time, an image was formed by setting the angle between the exposed surface of the photosensitive material and the exposure laser beam to 80 degrees, and the presence or absence of interference fringes in the image was compared.

The evaluation of the interference fringes was made into 5 grades. When the interference fringes were not visible, it was "5". When the interference fringes were visible but there was no problem in practical use, there was "3". There was "1", there was "5" and "3" was in between "4", and "3" and "1" was in between was "2".

Each light-sensitive material has 12
Development was performed using a heat drum under conditions of 0 ° C. for 20 seconds.

Table 1 shows the evaluation results of the interference fringes and the measurement results of the absorbance.

[0153]

[Table 1]

Table 1 shows that the light-sensitive material of the present invention is excellent.

Example 2 <Preparation of Organic Acid Silver Emulsion> While adding 840 g of behenic acid and 95 g of stearic acid to 12 liters of water and maintaining the temperature at 90 ° C., 48 g of sodium hydroxide and 63 g of sodium carbonate were added to 1.5 liter of water. What was melt | dissolved in was added. After stirring for 30 minutes, the temperature was raised to 50 ° C., and N-bromosuccinimide 1%
1.1 liter of aqueous solution was added, and then 2.3 liter of 17% silver nitrate aqueous solution was gradually added with stirring. Further, the liquid temperature was set to 35 ° C, and potassium bromide 2%
After 1.5 liter of an aqueous solution was added over 2 minutes and stirred for 30 minutes, a 1% aqueous solution of N-bromosuccinimide 2.5
One liter was added. While stirring this aqueous mixture, 3300% by weight of a butyl acetate solution of polyvinyl acetate 3300 was added.
After adding g, the mixture was allowed to stand for 10 minutes to separate into two layers, the aqueous layer was removed, and the remaining gel was washed twice with water. 2.6% of polyvinyl butyral (Denka butyral # 3000-K manufactured by Denki Kagaku Kogyo Co., Ltd.) was used as a mixture of gelled behenic acid / silver stearate and silver bromide thus obtained.
The dispersion was dispersed with 1800 g of an isopropyl alcohol solution, and further dispersed with 600 g of polyvinyl butyral (Denka Butyral # 4000-2 manufactured by Denki Kagaku Kogyo KK) and 300 g of isopropyl alcohol, and an organic acid silver salt emulsion (average minor axis: 0.05 μm, average major axis: 1 .2μm, coefficient of variation 25%
Needle-shaped particles). The average size of the silver bromide formed by the addition of potassium bromide was 0.06 μm.

<Preparation of Emulsion Layer Coating Solution> Each chemical was added to the organic silver emulsion obtained above in the following amount per mol of silver. Sodium phenylthiosulfonate 1 at 25 ° C
While stirring 0 mg and 50 mg of Dye 1 (used in Example 1), 2-mercapto-5-methylbenzimidazole 2 g, 4-chlorobenzophenone-2-carboxylic acid 21.5 g, 2-butanone 580 g and dimethylformamide 220 g. The mixture was added and left for 3 hours. Then, 8 g of 5-tribromomethylsulfonyl-2-methylthiadiazole,
2-tribromomethylsulfonylbenzothiazole 6
g, 4,6-ditrichloromethyl-2-phenyltriazine 5 g, disulfide compound a 2 g, 1,1-bis (2-hydroxy-3,5-dimethylphenyl) -3,
205 g of 5,5-trimethylhexane, 5 g of tetrachlorophthalic acid, 2.2 g of the following hydrazine derivative a, Megafax F-176P (fluorine-based surfactant manufactured by Dainippon Ink and Chemicals, Inc.) 1.1 g, 2 590 g butanone and 10 g methyl isobutyl ketone were added with stirring. In addition, the dyes described in Table 2 were added in amounts such that the absorbance in Table 2 was obtained. Further, 28 g of Byron 200 was added.

[0157]

Embedded image

<Emulsion Protective Layer Coating Solution> CAB171-15
S (cellulose acetate butyrate manufactured by Eastman Chemical Co., Ltd.) 75 g, 4-methylphthalic acid 5.7 g, tetrachlorophthalic anhydride 1.5 g, phthalazine 12 g, 0.3
g Megafax F-176P, Syldex H31
(New spherical silica made by Dokai Chemical Co., Ltd. average size 3 μm) 2 g,
A solution prepared by dissolving 10 g of sumidur N3500 (polyisocyanate manufactured by Sumitomo Bayer Urethane Co., Ltd.) in 3070 g of 2-butanone and 30 g of ethyl acetate was prepared.

<Back Surface Coating Liquid> Calcium Compound 1 was synthesized in the same manner as in Example 1.

12 g of polyvinyl butyral (Denka Butyral # 4000-2 manufactured by Denki Kagaku Kogyo KK), C
AB381-20 (cellulose acetate butyrate manufactured by Eastman Chemical Co., Ltd.) 12 g, 30 mg Dye 1 (Example 1), 75 mg calcium compound 1, 120 mg Dye 2
(Example 1) 5 mg of Dye 3 (Example 1), Sildex H121 (spherical silica average size 12 manufactured by Dokai Chemical Co., Ltd.)
.mu.m) 0.4 g, Sildex H51 (Dokai Chemical Industry Co., Ltd. spherical silica average size 5 .mu.m) 0.4 g, 0.1 g of Megafax F-176P, 2 g of sumidur N3500
-Butanone (500 g) and 2-propanol (500 g) were added with stirring to dissolve and mix.

The emulsion layer coating solution prepared as described above was coated on a 100 μm polyethylene terephthalate support which was not tinted with a blue dye so that the silver amount was 1.1 mg / m ^2, and then on the side opposite to the emulsion layer. The back surface coating solution was applied onto the top of the substrate so that the dry thickness was 3 μm. Further, an emulsion surface protective layer coating solution was applied on the emulsion surface to a dry thickness of 2 μm. The smoothness of the light-sensitive material thus obtained (J. TAPP
The Beck's smoothness was measured by using the Oken type smoothness measurement described in I-Pulp Test Method No. 5), and the emulsion side was 1000 seconds and the back side was 70 seconds.

However, in Comparative Samples 18 and 19, Dye 1 was added to the coating solution for the back surface to increase the absorbance of the back.

The refractive indices of the support, the photosensitive emulsion layer, the back layer and the protective layer are 1.665, 1.654 and 1.663, respectively.
It was 1.672. The refractive index was determined using an Abbe refractometer using a sodium lamp.

Further, the absorbance of the above light-sensitive material was measured in the same manner as in Example 1.

Observation of interference fringes The light-sensitive material produced above was uniformly exposed to light from the emulsion surface side of the light-sensitive material by an exposure machine using a semiconductor laser having a wavelength of 810 nm as an exposure source. A uniform image was formed with a subtracted optical density value of about 1.0. At this time, the exposure laser light was subjected to high-frequency superimposition to form a vertical multiple.

Each light-sensitive material was exposed 110 times after exposure.
Development was performed using a heat drum under conditions of 20 ° C. for 20 seconds.

Table 2 shows the evaluation result of the interference fringes and the measurement result of the spherical luminous intensity.

[0168]

[Table 2]

Table 2 shows that the light-sensitive material of the present invention is excellent.

[0170]

According to the present invention, the occurrence of interference fringes in an image can be eliminated.

Claims (4)

[Claims] 1. A photothermographic material having a photosensitive silver halide emulsion layer on a support, which is exposed by a laser beam having a wavelength of 700 nm or more, wherein the silver halide of the photosensitive silver halide emulsion layer is And the photosensitive silver halide emulsion layer has an absorbance of 0.3 or more at an exposure wavelength. 2. An exposure fringe in an image is improved by performing exposure by a laser scanning exposure machine in which an angle formed by a scanning laser beam and an exposed surface of a photosensitive material is not substantially vertical. No. 1 photothermographic material. 3. The photothermographic material according to claim 1, which is exposed by a laser scanning exposure machine in which scanning laser light is longitudinal multi, and interference fringes in an image are improved. 4. A support having a light-sensitive silver halide emulsion layer having a refractive index different from that of the support, and a protective layer having a refractive index different from that of the light-sensitive silver halide emulsion layer on the support.
Alternatively, the photothermographic material of item 3.