JP2939672B2 - Photothermographic material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photothermographic material, and more particularly to a photothermographic material having an improved minimum density (Dmin).

[0002]

BACKGROUND OF THE INVENTION Thermal development processing in which the development step is carried out by heating is known, and is known for obtaining a monochrome image and a color image. Also, a so-called transfer type photothermographic material which transfers an image obtained by thermal development from a photosensitive material to an image receiving layer is well known.

A photothermographic material usually has a binder, a photosensitive silver halide emulsion, a reducing agent, and, if necessary, a dye-providing substance, an organic silver salt and various other photographic additives on a support. doing. Further, in the transfer type photothermographic material, the case where the photosensitive material has an image receiving layer capable of receiving silver or a dye, and the case where the image receiving material has an image receiving layer capable of receiving silver or a dye separately from the photosensitive material. May be used together.

In particular, when a heat-developable light-sensitive material is used as a heat-developable color light-sensitive material, a method in which a dye image-receiving material is used, and an image dye is diffused and transferred to the dye-image receiving material after forming a diffusible dye image. It is preferable from the viewpoint of obtaining a dye image with high purity.

[0005] Regarding this method, many methods and improved techniques have been disclosed in the past.

When a diffusible dye image released or formed from a photothermographic material by thermal development is diffused and transferred to an image receiving material,
In the non-transfer portion, it is necessary to suppress generation of fog and stain as much as possible in order to obtain a high-quality transferred image. Therefore, many antifoggants and antistain agents have been conventionally proposed.

[0007] The photothermographic material performs thermal development at a high temperature compared to a photosensitive material subjected to ordinary wet processing, and thus easily generates various stain substances during thermal development. Further, since the generated stain substance is transferred to the image receiving layer without performing a step such as washing with water, the stain substance is easily transferred to the image receiving layer together with the image dye.

Japanese Patent Application Laid-Open No. 2-44356 discloses that in order to prevent such a colored substance generated during thermal development from being transferred to the image receiving layer,
There is disclosed a technique in which a substance that adsorbs a coloring substance is added to a photothermographic material in advance.

Specifically, the substance that adsorbs a coloring substance is as follows:
Activated carbon, ion exchange resin, silica gel and the like are described.

[0010] However, the addition of the coloring substance to the light-sensitive material can certainly reduce the coloring substance produced during thermal development, but if it is used as it is, there is a significant disadvantage in other photographic properties. found.

That is, it has been found that when a coloring substance is previously contained in a photothermographic material, photographic additives such as a sensitizing dye, a development inhibitor or a sensitizer are also adsorbed. Was. The adsorption of the sensitizing dye is particularly remarkable when the photothermographic material is stored for a long time under a high humidity condition, and significantly lowers the sensitivity in the color sensitized region. This problem can be alleviated to some extent by adding the adsorbed substance to a non-photosensitive layer such as an intermediate layer, an undercoat layer, or a protective layer.
It is not always sufficiently improved.

[0012]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a photothermographic material which contains solid particles which can effectively adsorb a coloring substance produced during heat development. An object of the present invention is to provide a photothermographic material which does not lower storage performance.

[0013]

SUMMARY OF THE INVENTION The object of the present invention is to provide at least a binder, a photosensitive silver halide, a dye-providing substance which releases or forms a diffusible dye during thermal development, and a coloring substance generated during thermal development on a support. In the photothermographic material containing solid particles to be adsorbed, the photothermographic material contains 0.5 to 10 mol% of a water-soluble chloride and bromide per 1 mol of all the photosensitive silver halide contained in the photothermographic material. The salt
At least 50 mol% with respect to the compound .

Hereinafter, the configuration of the present invention will be described in detail.

Examples of the solid particles for adsorbing coloring substances generated during thermal development of the present invention include, for example, “Design of Adsorbent / Adsorption Operation” (Hiroshi Yanai, published by Gihodo Shuppan Co., Ltd., Showa 57)
Year) Pages 1 to 10 can be used, and specifically, silica gel, natural zeolite,
Synthetic zeolite, activated clay, bauxite, alumina,
Activated carbon, metal-adsorbed carbon, ion-exchange resin and the like can be mentioned. Preferred are activated carbon, silica gel, natural and synthetic zeolites.

The solid particles adsorbing the coloring substance preferably have an average particle size of 0.05 to 2 μm, preferably 0.1 to 2 μm.
μm to 1 μm. Particularly preferably, it is 0.2 to 0.7 μm.

The solid particles adsorbing the coloring substance of the present invention can be added to any constituent layer of the photothermographic material. However, in order to maximize the effects of the present invention, the undercoat layer and the intermediate layer Alternatively, it is preferably added to the protective layer. The amount of the solid particles added is 0.01 g / m ^{2 of the} photothermographic material.
５5 g, preferably 0.02 g to 1 g.

In the method of adding the solid particles to the photothermographic material, the solid particles are dispersed in a hydrophilic binder in a fine particle state,
This is used as a constituent layer of the photothermographic material (preferably an undercoat layer,
Used in a coating solution for forming an intermediate layer and a protective layer).

The photothermographic material of the present invention may contain 0.5 to 10 mol% of a water-soluble chloride based on the total light-sensitive silver halide.
Containing things and smell monster. Here, when the water-soluble chloride and bromide <br/> prepared by itself in an aqueous solution, chloride ions and odor
It refers to compounds which release hydrogen ions, specifically refers sodium, potassium, magnesium, ammonium, zinc, calcium, chloride and odor products such as lithium.

The effect of the present invention when less than 0.5 mol% of chloride and smell product against light-sensitive silver halide emulsion was not added, i.e., from the silver halide grains in the storage of the sensitizing dye The desorption prevention effect cannot be obtained.

Further, water-soluble chlorides and odor products for light-sensitive silver halide used in 10 mol% or less. When used in an amount exceeding 10 mol%, desensitization and a decrease in developability of the photosensitive silver halide begin to occur.

[0022] Among the chloride and odor compound, in particular the amount of water-soluble chloride relative to the total light-sensitive silver halide, 0.5 mol%
Moreover halt to minimize desensitization adding 1 0 mol% or less on than, preferably to elicit the effects of the present invention to its fullest extent.

[0023]

[0024] The water-soluble chlorides and odor product can be added in any layer of the photographic constituent layers of the photothermographic material of the present invention. Since the water-soluble chloride and bromide of the present invention have extremely high water-solubility, they readily diffuse in the hydrophilic binder during coating or storage of the photographic constituent layer and are relatively dispersed in the constituent layer of the photothermographic material. A uniform distribution is achieved in a short time.

Therefore, the water-soluble chloride
It is possible to add objects and odor product. As a special case, a water-soluble chloride and odor compound, the effect of improving the stagnation of the coating solution containing a photosensitive silver halide may have, in such case, to form a photosensitive layer It is preferably added to the coating solution.

[0026] The water-soluble chlorides and odor compound is not added as a pre-water-soluble chlorides and odor products, upon application and the photothermographic material, a certain period (e.g. aging temperature is managed after application the decomposition and reaction period) during the time of but also containing chloride and odor products such as is released. Examples of the present invention include chlorides and bromides formed by the hardening of a gelatin film by using a chlorine or bromine releasing compound or by using an active chlorine or bromine releasing hardener. Is contained.

The method for confirming the amount of water-soluble chlorides and odor products of photothermographic material was extracted into the aqueous solution a quantity of the photothermographic material, known suitable manner halogen ion content of this (for example, the silver potential Titration, ion concentration meter, ion chromatography, etc.).

As the photosensitive silver halide used in the photothermographic material of the present invention, any silver halide can be used, but the silver iodide content is preferably 2 mol% or less, particularly preferably 1 mol% or less. Silver chloride, silver bromide, silver chlorobromide and silver chloroiodobromide. More preferably, a silver bromide or silver chlorobromide or silver bromide having a silver bromide content of 80 mol% or more satisfies both performances of desorption of sensitizing dyes and suppression of development of halogen ions. It is preferable because of its size.

The silver chlorobromide emulsion generally has a particle size of 0.05.
１1 μm, preferably 0.1-0.5 μm. In particular, silver halide spectrally sensitized with a sensitizing dye is preferably 0.1 to 0.4 μm.
When the value is m, the effect of the present invention is great. The silver halide may have a uniform composition from the inside to the surface of the grain, or may have a composition that changes continuously or stepwise between the inside and the surface.

The shape of the silver halide may be one having a distinct crystal habit such as tabular, cubic, spherical, octahedral, dodecahedral, or tetrahedral, or the like, but is preferably cubic. When a silver halide emulsion is used, the water-soluble silver halide emulsion of the present invention has a large effect of preventing desensitization during storage.

Further, for example, US Pat. Nos. 2,592,250 and 3,2,250
20,613, 3,271,257, 3,317,322, 3,511,62
No. 2, 3,531,291, 3,447,927, 3,761,266,
Internal latent image type silver halide emulsions described in JP-A Nos. 3,703,584, 3,736,140, 3,761,276, JP-A-52-15661, and JP-A-55-127549 can also be used.

In the photosensitive silver halide, metal ion species such as iridium, gold, rhodium, iron and lead can be added in the form of a suitable salt at the stage of grain formation.

In the present invention, as a method for preparing a photosensitive silver halide, a photosensitive silver salt-forming component such as a water-soluble halide is allowed to coexist with an organic silver salt described later, and a part of the organic silver salt is subjected to the photosensitive halide. It can also be formed by converting to a part of silver.

The photosensitive silver halide emulsion is prepared by chemically sensitizing the surface of silver halide grains with a known sensitizer (eg, active gelatin, inorganic sulfur, sodium thiosulfate, thiourea dioxide, sodium chloroaurate, etc.). And chemical sensitization can also be carried out in the presence of a nitrogen-containing heterocyclic compound or a mercapto group-containing heterocyclic compound.

Further, the photosensitive silver halide can be subjected to spectral sensitization to blue, green, red, and near-infrared light by a known spectral sensitizing dye such as cyanine and merocyanine used in ordinary photography.

These sensitizing dyes are used in an amount of 1 μmol to 1 mol, preferably 10 μmol to 0.1 mol, per 1 mol of silver halide.
Can be added at the time of formation of silver halide grains, at the time of removal of soluble salts, before chemical sensitization, at the time of chemical sensitization, or after the end of chemical sensitization.

In the photothermographic material of the present invention, known organic silver salts can be used for the purpose of increasing sensitivity and improving developability.

The organic silver salt which can be used in the present invention is
For example, JP-B-43-4921, JP-A-49-52626, 52-14
No. 1222, No. 53-36224, No. 53-37626, No. 53-36224,
Nos. 53-37610 and other publications and U.S. Pat.
Nos. 3,794,496 and 4,105,451, etc., silver salts of long-chain aliphatic carboxylic acids and silver salts of carboxylic acids having a heterocyclic ring (for example, silver behenate, α- (1-phenyltetrazolethio) Silver acetate etc.), JP-B-44-26582, 45-
No. 12700, No. 45-18416, No. 45-22815, JP-A-52-1373
No. 21, No. 58-118638, No. 58-118639, U.S. Pat.
Silver salts of compounds having an imino group described in JP-A No. 274 and the like and acetylene silver described in JP-A-61-249044 can be exemplified.

Particularly preferred are silver salts of compounds having an imino group, and particularly preferred are silver salts of benzotriazole and its derivatives (for example, silver benzotriazole, silver 5-methylbenzotriazole, etc.).

The photothermographic material of the present invention is used as a black-and-white or color photographic material. When used as a color photographic material, a dye-providing substance is used.

Examples of the dye-donor include, for example, JP-A-61-6
No. 1157, No. 61-61158, No. 62-44738, No. 62-129850
No. 62-129851, No. 62-129852, No. 62-169158,
Couplers forming diffusible dyes described in Japanese Patent Application No. 1-200859, such as leuco dyes described in JP-A-61-88254, azo dyes described in U.S. Pat.No. 4,235,957, or U.S. Pat. No. 4,439,513, JP-A-59-60434,
59-65839, 59-71046, 59-87450, 59-123
Nos. 837, 59-124329, 59-165054, and 59-165055. In particular, a compound that forms a diffusible dye by a coupling reaction is preferable, for example, JP-A-2-863
It is represented by the general formula (A) on the second line of the lower left column on page 9 of the publication.

Among them, a polymer coupler having a polymer chain having a repeating unit derived from a monomer represented by the general formula (II) described in the right column of the lower right column on page 9 of the same publication is preferable.

Examples of the positive dye-providing substance include:
JP-A-59-55430, JP-A-59-165054, JP-A-59-154445,
59-116655, 59-124327, 59-152440, 64-13
There are compounds described in various publications such as No. 546.

The above dye-providing substances may be used alone or in combination of two or more.

Further, the photothermographic material of the present invention includes, for example,
JP-A-2-293753 and JP-A-2-308162, together with a polymerizable compound, a dye-providing substance is contained in a microcapsule, and this is thermally developed, so that the polymerization reaction of the polymerizable compound is image-formed. Alternatively, the present invention can be applied to a photothermographic material of a system in which an image is formed by causing microcapsules to be hardened and changing the diffusibility of a dye-providing substance into an image-receiving layer by inverting the microcapsules.

The photothermographic material of the present invention may contain a known mercapto compound as an antifoggant or a development accelerator. Whether the mercapto compound functions as an antifoggant or a development accelerator depends on the method of thermal development, but the desorption of the sensitizing dye by the adsorptive solid particles was due to the presence of such a mercapto compound. It is easily accelerated in the case, and if sufficient water-soluble halide is added to completely prevent this, the sensitivity decreases,
Alternatively, a remarkable decrease in developability is likely to occur.

However, the desorption of the sensitizing dye by such a mercapto compound is small when a compound having a mercapto group having a water-soluble group is used, and the effect of the present invention by the water-soluble halide of the present invention is maximized. Can be demonstrated.

The mercapto compound having a water-soluble group preferably used in the present invention is a mercapto compound having at least one amino group, carboxyl group, sulfo group, hydroxyl group, sulfinic acid group and phosphite group, For example, the following compounds can be mentioned.

[0049]

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In addition to the above, see, for example, JP-A-63-153539.
Nos., (A-1) to (A-10), (A-1) described on pages 6 to 8
3), (A-16), (A-19), (A-21), (A-22), (A-34) to (A-3)
7), (A-40), (A-41), (1) to (24) described in JP-A No. 3-7113, pp. 3 to 5; 1,3,5,6,7,8,9,13,14,1 described on page 7
5, 16, 17, 18, 19, 20, 21, 27, 29, 31, 32, 33, 3
4, 35, 36, 37, 38, 39, 40 and the like.

These mercapto-based compounds having a water-soluble group are used in an amount of 0.1 mol per mol of the total photosensitive silver halide emulsion.
~ 50 mmol can be used, but preferably 0.5
Used in the range of 2020 mmol. The reducing agent used in the photothermographic material of the present invention is selected from those conventionally known for photothermographic materials by a developing mechanism and a dye formation or release mechanism. The reducing agent referred to herein includes a reducing agent precursor that releases the reducing agent during thermal development.

Examples of the reducing agent that can be used in the present invention include, for example, US Pat. Nos. 3,351,286 and 3,761,270,
3,764,328, 3,342,599, 3,719,492, Research Disclosure 12,146, 15,108
No. 15,127, and JP-A-56-27132, 53-135628
No. 57-79035, p-phenylenediamine and p-aminophenol developing agents, phosphoramidophenol developing agents, sulfonamidoaniline developing agents, and hydrazone developing agents, phenols, sulfone Amidophenols, polyhydroxybenzenes,
There are naphthols, hydroxybisnaphthyls, methylenebisphenols, ascorbic acids, 1-aryl-3-pyrazolidones, hydrazones, and precursors of the above various reducing agents.

The dye-providing substance can also serve as a reducing agent.

In the photothermographic material of the present invention, a thermal solvent can be used for the purpose of accelerating the transfer of a dye and other purposes. The thermal solvent is a compound which is liquefied during thermal development and has an action of promoting thermal development and thermal transfer of a dye, and is preferably in a solid state at normal temperature.

Examples of the thermal solvent which can be used in the present invention include, for example, US Pat. Nos. 3,347,675, 3,667,959,
438,776, 3,666,477, Research Disclosure No. 17,643, JP-A-51-19525, 53-24829, 5
3-60223, 58-118640, 58-198038, 59-2295
No. 56, No. 59-68730, No. 59-84236, No. 60-191251,
No. 60-232547, No. 60-14241, No. 61-52643, No. 62-78
No. 554, No. 62-42153, No. 62-44737, No. 63-53548,
No. 63-161446, JP-A No. 1-224751, No. 2-863, No. 2-12
Compounds described in each gazette such as 0739 and 2-123354 are exemplified. Specifically, urea derivatives (urea, dimethylurea, phenylurea, etc.), amide derivatives (eg, acetamido, stearylamide, p-toluamide, p-propanoyloxyethoxybenzamide, etc.), sulfonamide derivatives (eg, p-toluene Sulfonamides) and polyhydric alcohols (eg, 1,6 hexanediol, pentaerythritol, polyethylene glycol, etc.) are preferably used.

The above thermal solvent can be added to any layer such as a light-sensitive silver halide emulsion layer, an intermediate layer, a protective layer, or an image receiving layer of an image receiving material. Wt% to 500 wt%, more preferably 20 wt% to 2 wt%
00% by weight.

The binder used in the photothermographic material of the present invention includes, for example, binders described in JP-A No. 2-863, page 10, upper right column, line 14 to lower left column, line 10, including preferred combinations. Can be used. Particularly preferred binders are gelatin, polyvinylpyrrolidone and combinations thereof.

Various additives can be added to the photothermographic material of the present invention, if necessary, in addition to the above.

As the development accelerator, for example, JP-A-59-177
No. 550, No. 59-111636, No. 59-124333, No. 61-72233
No. 61-236548, JP-A-1-152454, JP-A-61-1596
No. 42, JP-A-1-104645, and development accelerator releasing compounds described in Japanese Patent Application No. 1-110767, or metal ions having an electronegativity of 4 or more described in JP-A-1-104645 can also be used. .

As antifoggants, for example, US Pat.
No. 645,739, higher fatty acids, second mercury salts described in JP-B-47-11113, N-halides described in JP-A-51-47419, U.S. Pat. No. 3,700,457,
JP-A-51-50725, Japanese Patent Application Nos. 1-69994 and 1-104271, mercapto compound-releasing compounds described in JP-A-49-12501
Arylsulfonic acid described in No. 6, lithium carboxylate described in No. 51-47419, oxidizing agents described in British Patent No. 1,455,271 and JP-A-50-101019, sulfinic acids and thiosulfonic acids described in No. 53-19825, Thiouuracils described in No. 51-3223, Sulfur described in No. 51-26019, 51-42529
No. 51-81124, and disulfides and polysulfides described in 55-93149, rosin or diterpenes described in 51-57435, and having a carboxyl group or a sulfonic acid group described in 51-104338. Polymeric acid, U.S. Patent 4,13
Thiazolythion described in 8,265, JP-A-54-51821, 5
No. 5-142,331, triazoles described in U.S. Pat.No.4,137,079, thiosulfinic acid esters described in JP-A-55-140883, JP-A-59-46641, JP-A-59-57233, JP-A-59-57234. Di- or tri-halides, thiol compounds described in JP-A-59-111636, JP-A-60-198540 and JP-A-60-227255
Hydroquinone derivatives described in JP-A-62-78554, antifoggants having a hydrophilic group described in JP-A-62-78554, JP-A-62-121452
Antifoggant having a ballast group described in JP-A-62-123456, JP-A-1-61239
And the non-colored couplers described in (1).

Various known photographic additives other than those described above can be used in the photothermographic material of the present invention. Examples thereof include antihalation dyes, antiirradiation dyes, colloidal silver, fluorescent brighteners, It may contain a hardening agent, an antistatic agent, a surfactant, an inorganic or organic matting agent, an anti-fading agent, an ultraviolet absorber, an antifungal agent, a white background color adjusting agent and the like. For example, RD (Research
Disclosure) No. 17029, No. 29963, JP-A Nos. 62-135825 and 64-13546.

These various additives can be appropriately added not only to the photosensitive layer but also to any constituent layer such as an intermediate layer, an undercoat layer, a protective layer or a backing layer.

As the support used in the photothermographic material of the present invention, for example, the support described in page 12 of JP-A-2-863, line 15 from the upper left column to line 1 in the upper right column can be used. . Preferably, a polyethylene terephthalate support or a paper support having a white pigment on a paper substrate such as cast-coated paper or baryta paper is used.

When the photothermographic material of the present invention is of a transfer type, an image receiving material is preferably used. The image receiving material is
It is composed of a support and an image receiving layer having a dye receiving ability provided thereon. The support itself can also serve as an image receiving layer having a dye receiving ability.

The image receiving layer can be broadly divided into a case where the binder constituting the image receiving layer itself has a dye receiving ability, and a case where a mordant capable of receiving a dye is contained in the binder. When the binder has a dye-accepting ability, a substance preferably used has a glass transition temperature of about 40 ° C. or more and about 250 ° C.
It is preferably formed of a polymer having a temperature of not more than ℃, specifically, “Polymer Handbook Second Edition” (Joy Brand Wrap, EH.
Inmargat), John Willie and Sons Publishing, Polymer Handbook 2nd. Ed. (J. Brandrup, E.
H. Immergut) Synthetic polymers having a glass transition temperature of about 40 ° C. or more described in John Wily & Sons II are useful. Generally, the molecular weight of the polymer is 2,000 to 20.
A value of about 0,000 is useful. These polymers may be used alone or in combination of two or more, or may be copolymerizable polymers having two or more types of repeating units.

Specifically, JP-A No. 2-863, page 14, upper left column 1
The polymers described from the fourth line to the upper right column, line 14 can be used, including preferred polymers.

In the image receiving material in which the image receiving layer contains a mordant in a binder, a polymer containing a tertiary amine or a quaternary ammonium salt is preferably used as the mordant. For example, US Pat. No. 3,709,690 and US Pat. 1964-
Compounds described in JP 13546 gazette and the like can be mentioned. As a binder used for holding these mordants, a hydrophilic binder such as gelatin or polyvinyl alcohol is preferably used.

A dye receiving layer obtained by dispersing a hydrophobic polymer latex having dye receiving ability in a hydrophilic binder in a similar manner to the image receiving layer having the mordant in the binder can also be used in the present invention.

The image-receiving material of the present invention may have a single image-receiving layer provided on a support, or may have a plurality of constituent layers coated thereon. It may be an image receiving layer, or only a part of the constituent layers may be an image receiving layer.

When the image receiving material has a support separately from the image receiving layer, the support of the image receiving material may be either a transparent support or a reflective support, and is described in JP-A-2-863, page 14, lower left. The support described in column 15 line to lower right column line 8;
It can be used by selecting from a reflective support having a second type diffuse reflectance.

Various known additives can be added to the image receiving material of the present invention. Such additives include, for example, antifouling agents, ultraviolet absorbers, fluorescent whitening agents, image stabilizers, development accelerators, antifoggants, pH regulators (acid and acid precursors, base precursors, etc.), heat Examples thereof include solvents, organic fluorine compounds, oil droplets, surfactants, hardeners, matting agents, and various metal ions.

The photothermographic material of the present invention can be exposed by known exposure means suitable for the color sensitivity of the photosensitive material.

As the exposure light source that can be used, those described in JP-A-2-863, page 12, lower left column, lines 13 to 16 can be used.
T light source and LED are used. Further, a light source in which a semiconductor laser and an SHG element (second harmonic generation element) are combined can also be used.

The photothermographic material of the present invention is preferably used at 70 to 200 ° C., more preferably 90 to 170 ° C., preferably for 1 to 180 seconds, more preferably for 2 to 180 seconds after or simultaneously with imagewise exposure. Heat development is performed for 120 seconds to form a dye image. The transfer of the diffusible dye to the image receiving material may be performed simultaneously with the heat development by bringing the image receiving layer surface of the image receiving material into close contact with the photosensitive layer side of the photosensitive material during the heat development, or the image receiving material may be exposed after the heat development. The dye may be transferred in close contact with the material, and after supplying water, the photosensitive material and the image receiving material may be closely attached. Prior to exposure, the photosensitive material may be preheated at a temperature in the range of 70 to 160 ° C. or disclosed in JP-A-60-143338 and JP-A-61-16.
Immediately before development, at least one of the photosensitive material and the image receiving material can be preheated at a temperature in the range of 80 to 120 ° C., as described in JP-A-2041.

In the heat development of the photothermographic material of the present invention, known heating means can be applied. For example, JP-A-2-863, page 13, upper left column, lines 12 to 19 The method described, a method using far-infrared heating, and the like can be used.

The heating pattern at the time of thermal development is not particularly limited, and a method of performing the development at a constant temperature, a method of performing the initial development at a high temperature and performing the latter half of the development at a low temperature, or the reverse method,
Further, the method can be performed by an arbitrary method such as a method of changing the temperature region in three or more steps or a method of continuously changing the temperature.

[0077]

EXAMPLES Examples of the present invention will be shown below, but the embodiments of the present invention are not limited thereto.

[Preparation of Photothermographic Material] A photothermographic material 1 having the following layer constitution was prepared on a photographic baryta paper having a thickness of 160 μm.

Here, the added amount of each material is shown per 1 m ^{2 of the} photothermographic material.

The photosensitive silver halide emulsion and the organic silver salt were each expressed in terms of silver. (The same amount of the following additives is used.) (Layer composition of photothermographic material 1) Subbing layer Polyphenylene ether 2.0g Polystyrene 2.0g Antifoggant-2 1.0g First layer (red photosensitive layer) Benzo Triazole silver 1.6 g Tricresyl phosphate (TCP) 0.03 g Dye-donating substance (3) 1.2 g Red-sensitive silver halide emulsion 0.68 g (Ag) Gelatin 1.3 g Polyvinylpyrrolidone (K-30) 0.6 g Thermal solvent-A 4.5 g Anti-irradiation dye-2 0.01 g FR-1 0.005 g Scavenger A 0.1 g Second layer (first intermediate layer) Gelatin 0.8 g Reducing agent 1.12 g TCP 0.2 g Third layer (green photosensitive layer) Benzotriazole silver 0.8 g TCP 0.2g Dye-donating substance (2) 0.9g Green-sensitive silver halide emulsion 0.47g (Ag) Gelatin 2.0g PVP (K-30) 0.3g Hot solvent-A 3.45g Anti-irradiation dye- 1 0.02g FR-1 0.003 g Scavenger A 0.08g 4th layer (2nd intermediate layer) Gelatin 1.55g 1.5g UV absorber-1 0.3g TCP 0.22g Yellow filter dye 0.26g Fifth layer (blue photosensitive layer) Silver benzotriazole 1.5g TCP 0.344g Dye donating substance (1) 1.2g Blue-sensitive silver halide emulsion 0.45g (Ag) Gelatin 1.6 g PVP (K-30) 0.4 g Thermal solvent-A 4.0 g FR-1 0.002 g Scavenger A 0.1 g Sixth layer (protective layer) Gelatin 1.0 g Polyvinylpyrrolidone (K-30) 0.2 g ZnSO ₄ 0.65 g Reducing agent 0.34 g TCP 0.2 g DAP 0.1 g Ultraviolet absorber-1 0.4 g Each addition amount represents the weight per 1 m ² . Each layer,
It contains 0.03 g of bisvinylsulfonylmethyl ether as a hardener per 1 g of gelatin and also contains surfactant-1 required for coating. The reducing agents are reducing agent-1 and reducing agent-
2 is a mixture of 7: 3 (weight ratio).

The structural formula of the additive used in the photosensitive layer of the photothermographic material is shown below.

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[0083]

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[0084]

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[Silver Benzotriazole Emulsion] The mixture was adjusted by simultaneous mixing of an aqueous solution of ammoniacal silver nitrate and benzotriazole (containing 0.2 mol of ammonia water with respect to benzotriazole) in a 10% aqueous solution of phenylcarbamoyl gelatin at 50 ° C., and the addition was completed. Reduce the pH of the post solution, aggregate and desalinate to form needle-like crystals (0.1-0.2 μm wide, 0.5-2 μm long)
m).

To this, ST-2 was added as a stabilizer in an amount of 20 mg per mol of silver benzotriazole.

[0087] The photosensitive silver halide grain emulsion used (Ag C lB
r) is shown in the table below.

Item Blue photosensitive green photosensitive (GEM-1) Red photosensitive halogen composition (Br mol%) 70 60 70 Particle shape Hexagonal cubic cubic Average particle size * 1 0.30 μm 0.19 μm 0.20 μm Particle size Distribution coefficient * 2 0.15 0.17 0.13 Surface chemical sensitization method * 3 S + Au S S + Au Stabilizer ST-1 ST-1 ST-2 Sensitizing dye BSD-1 GSD-1 RSD-1 * 1 Spherical diameter * 2 grains Diameter distribution coefficient = (Standard diameter of particle size distribution) / (Average particle size) * 3 S + Au: Gold-sulfur sensitization with sodium thiosulfate and potassium chloroaurate S: Sulfur sensitization with sodium thiosulfate Each silver emulsion was added at the time of grain formation with 10 ^-6 mole of sodium iridium (IV) chloride per mole of silver halide.

ST-1: 5-methyl-1,3,3a, 7-tetrazaindene Each chemical sensitization was carried out in the presence of a sensitizing dye.

[0090]

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Next, in the photothermographic material 1, the layers
2, the layer -4, the addition of activated carbon to adsorb the coloring material shown in Table 1 in the layer -6, further to prepare a photothermographic material -2～24 of varying water-soluble chlorides and odor product weight.

The activated carbon was wet-pulverized in a 0.2% aqueous polyvinylpyrrolidone solution using glass beads of 0.5 mm by a sand mill disperser for 20 hours to obtain an activated carbon dispersion having an average particle size of about 0.4 μm.

[0093] The amount of water-soluble chlorides and odor products each of sodium chloride and, by adjusting the added amount using the sodium bromide, water-soluble chlorides thermal current-sensitive material contains and odor product amount photothermographic material of 100 cm ² was extracted in pure water of 20 cc, it was determined by measuring chloride ion, a bromide ion of the aqueous solution.

[Preparation of Image-Receiving Material] An image-receiving layer having the following composition was coated on the same photographic barrayer support as used for preparing the photothermographic material to prepare an image-receiving material. (The amount of addition is the amount per 1 m ² of the image receiving material.) Polyvinyl chloride (average degree of polymerization 500) 10 g Image stabilizer-1 1.1 g Image stabilizer-2 0.3 g Image stabilizer-3 0.5 g Image stabilizer- 4 0.5g Image stabilizer-5 0.3g Hot solvent-B 4.2g

[0095]

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[Evaluation of Photothermographic Material] Each of the obtained photothermographic materials was stored at 50 ° C. and a relative humidity of 60% for 3 days. Heat development was performed at 150 ° C. for 60 seconds.

Next, the photothermographic material was superimposed on the image receiving material-1, and superposed at 120 ° C. for 20 seconds to perform dye transfer. Sensitometry was performed on the magenta dye image of the obtained dye image to determine Dmax and sensitivity. Table 1 shows the results.

[0098]

[Table 1]

From the results shown in Table 1, it can be seen that the photothermographic material containing 0.5 to 10 mol% of water-soluble chloride with respect to the photosensitive silver halide emulsion has good white background contamination (lowest density Dmin is low). Moreover, it can be seen that there is almost no decrease in the maximum density Dmax. Moreover even when the store photothermographic material, the photothermographic material of the present invention the photothermographic amount of reduced water-soluble chlorides and odor products of reduction and Dmax of sensitivity is less than the amount of the present invention It can be seen that it is smaller than the material.

Example 2 In the photothermographic materials 6 to 10 prepared in Example 1,
Photothermographic material with activated carbon changed to silica gel-21 to 25
It was prepared and evaluated in the same manner as in Example-1.

Table 2 shows the results.

[0102]

[Table 2]

The results in Table 2 show that the effect of the present invention can be obtained even when the activated carbon is changed to silica gel.

Example 3 In the photothermographic materials 1, 4, 6, and 9 of Example 1, the photosensitive silver halide emulsion of the layer 3 was changed from GEM-1 to G shown in Table 3 below.
Except for changing to EM-2 to GEM-5, the photothermographic materials 1, 4,
Photothermographic materials 26 to 45 were prepared in the same manner as in Examples 6 and 9, and the photothermographic materials were evaluated in the same manner as in Example 1.

Table 4 shows the results.

[0106]

[Table 3]

[0107]

[Table 4]

[0108] From the results of Table 4, than if the direction of silver chlorobromide emulsions as light-sensitive silver halide emulsion was used silver iodobromide emulsion, the desensitization prevention due to storage of the water-soluble chlorides and odor product It turns out to be effective. Further, it can be seen that the storage stability was slightly deteriorated by changing the crystal wall of the silver halide grains from cubic to tetradecahedral.

Example 4 Photothermographic materials -46 to 55 were prepared in the same manner as in Example 1, except that the mercapto antifoggant was changed from FR-1 to FR-4. The photothermographic material was evaluated in the same manner as in Example-1. Table 5 shows the results. From the results shown in Table 5, it can be seen that the effects of the present invention can be obtained even when the mercapto compound having a water-soluble group is changed from FR-1 to FR-4 in the photothermographic material of the present invention.

[0110]

[Table 5]

Example -5 The photothermographic material 56 obtained by changing the mercapto antifoggant used in the photothermographic materials-1 to 10 of Example 1 from FR-1 to ST-2 (equimolar). Created ~ 65. Example-
Evaluation was performed in the same manner as in Example 1, and the results shown in Table 6 were obtained.

[0112]

[Table 6]

From the results shown in Table 6, when a compound having no hydrophilic group was used as the mercapto antifoggant,
The effect of the present invention, that is, the effect of suppressing stain and preventing storage desensitization, slightly decreases.

[0114]

According to the present invention, it is possible to provide a photothermographic material containing solid particles capable of effectively adsorbing a coloring substance generated at the time of heat development and not deteriorating the storage performance of the photothermographic material.

Claims (1)

(57) [Claims] 1. A support comprising at least a binder, a photosensitive silver halide, a dye-providing substance that releases or forms a diffusible dye during thermal development, and solid particles that adsorb a coloring substance generated during thermal development. In the photothermographic material, 0.5 to 10 mol% of water-soluble chloride and 1 mol of the total light-sensitive silver halide contained in the photothermographic material are used.
Containing bromide , wherein the molar ratio of the bromide to the chloride is
A photothermographic material comprising 50 mol% or less .