JPH1152510A - Heat-developable photosensitive material and developing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the heat-developable photosensitive material good in photographic performance and superior in passableness through a heat developing machine by regulating an ANSI curl absolute value to a specified value when heat-developed. SOLUTION: The heat-developable photosensitive material has the ANSI curl absolute value of >=0.5 when heat-developed, preferably, in the range of 0.5-5.0, and it is preferred that it contains photosensitive silver halide, and an organic silver salt and its reducing agent on a support. It is preferred that at least one photosensitive layer containing photosensitive silver halide is provided on at least one side of the support and this layer contains a polymer latex in an amount of >=50 weight 5 % of the total binder. As the means for controlling the curl when heat-developed, the method of controlling a coating amount of a hydrophilic polymer for coating the side of the support same as the photosensitive layer and that for mcaoating the side reverse to the photosensitive layer.

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 a developing method, and more particularly, to a photothermographic material having excellent heat-developability.

[0002]

2. Description of the Related Art It is well known that a photosensitive layer is formed on a support and a latent image formed by exposure is converted into a visible image by thermal development.

[0003] For example, US Pat.
No. 57075, and D.A. Morgan and B.A. "Thermally Processed Silver Systems" by Shely, Imaging Processes and Materials (Imagi
ng Processes and Materials) Neblette 8th edition, Sturge, V.S. Walworth, A .;
Shepp, page 2, 1969).

[0004] These methods meet social demands for simplification of processing and environmental preservation, which have been increasing in recent years.

Usually, these photothermographic materials are thermally developed by bringing them into contact with a high-temperature object such as a high-temperature drum. In the case where the photothermographic material is heated without being brought into contact with a high-temperature object to be thermally developed (for example, a method in which the material is brought into contact with high-temperature air or a method using infrared rays), the photothermographic material is usually exposed to heat with a roller or belt at a high temperature. Material must be transported.

On the other hand, in the photothermographic material, a polymer is used as a base, a binder for a photographic layer, etc., so that at high temperatures, the tackiness increases, the elastic modulus decreases, and the so-called "toughness" decreases. And easily adhere to rollers and belts. When the photothermographic material adheres to a roller or a belt, conveyance failure (so-called jamming) occurs, which is a serious problem in practical use.

[0007] Conventionally, a technique for improving defective conveyance has been known. For example, a method is known in which a surface in contact with the photothermographic material, such as a drum, a roller, or a belt that conveys the photothermographic material, is made of a material having low adhesiveness. Specifically, a method is known in which a drum, a roller, and a belt are made of a low-adhesion material such as a fluororesin, or a surface is coated with a low-adhesion material such as a fluororesin. Further, a method of processing the surface of a drum, a roller, a belt, or the like into a shape in which the photothermographic material does not easily adhere is also known. Mirror finish, satin finish, etc. are adopted as the surface shape.
However, simply devising the material and shape of the drum, roller, belt, etc., completely prevents poor transport of the photothermographic material, which tends to adhere to the roller or belt due to the decrease in "strength" as described above. I couldn't do that.

[0008] Other techniques for improving defective conveyance include a drum,
There is also known a method in which a photothermographic material adhered to the surface of a roller or a belt is forcibly peeled off by a scraper, air suction, air blowing, or the like. However, the scraper has a problem that the drum and the like are damaged, and the use of air causes a non-uniform heat development temperature, so that the image quality of the developed photothermographic material is deteriorated.

As described above, the conventional method cannot completely eliminate the poor transport of the photothermographic material, and an improved technique has been desired.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to provide a photothermographic material and a developing method which are excellent in photographic properties and excellent in passage through a heat developing machine.

[0011]

The above object has been achieved by the following means. (1) A photothermographic material, wherein the absolute value of ANSI curl during thermal development is 0.5 or more. (2) A photosensitive silver halide, an organic silver salt, and a reducing agent for the organic silver salt are provided on a support, and at least one surface of the support contains at least one layer of the photosensitive silver halide. A photosensitive layer, wherein the polymer latex is used as 50% by weight or more of the total binder of the photosensitive layer, and the photosensitive layer is coated with a coating solution in which 30% by weight or more of a solvent is water and the binder is dispersed. The photothermographic material according to (1), which is formed by drying. (3) 25 ° C. 6 of the polymer of the polymer latex
The photothermographic material according to the above (1) or (2), wherein the equilibrium water content at 0% RH is 2% by weight or less. (4) The photothermographic material according to any one of the above (1) to (3), having a non-photosensitive layer in which at least 30% by weight of all binders is a hydrophilic polymer. (5) The photothermographic material according to (4) above, wherein the hydrophilic polymer is gelatin. (6) In the method in which the photothermographic material according to any one of the above (1) to (5) is conveyed on a heat drum by rotation of a heat drum to thermally develop the photothermographic material, A method for developing a photothermographic material, wherein the photothermographic material is transported so as to curl outward from a tangent at the peeling point of the photothermographic material of the heat drum.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
In the photothermographic material of the present invention, the absolute value of ANSI curl at the time of thermal development is 0.5 or more.

The ANSI curl value referred to here is the reciprocal of the radius of curvature of the curled photothermographic material expressed in m (meters), and + and-are added to this value according to the following criteria. It was done. Note that when this value is 0, no sign is given.

The measurement of the ANSI curl value during thermal development is performed as follows. The temperature of the ambient temperature and humidity at which the thermal development is performed is raised to the temperature of the thermal development, and the photothermographic material is put therein, and the radius of curvature when the temperature and the moisture absorption are equilibrated is measured. Calculate curl value by method. However, in the case of a photothermographic material having a photosensitive layer on one side, when the curl is made so that the photosensitive layer is on the outside, + is used, and vice versa.
In the case of a photothermographic material having a photosensitive layer on both sides, the curl value is +.

If the absolute value of the ANSI curl is less than 0.5, the transportability in the heat developing machine becomes poor. The ANSI curl may be 0.5 or more, but if it is too large, it becomes difficult to use the photothermographic material greatly when using the photothermographic material. Therefore, the absolute value of the ANSI curl is preferably in the range of 0.5 to 5.0. Further, considering that the photothermographic material is used in various environments, this value is 1.0 to 3.0.
Is more preferable.

In other words, by restricting the absolute value of ANSI curl to 0.5 or more, the passability in a heat developing machine is improved. On the other hand, when the absolute value of the ANSI curl value is less than 0.5, the effect of improving the passage property in the heat developing machine becomes insufficient. The preferred range of the absolute value of the ANSI curl value is set to 0.5 to 5.0 because if the value is too large, the curl at the time of use of the photothermographic material becomes large, which is not preferable. By setting the range to 1.0 to 3.0, passability that is not affected by the use environment conditions is secured.

Means for controlling the curl during thermal development of the photothermographic material of the present invention include, for example, the surface of the photothermographic material on which the photosensitive layer is coated (photosensitive surface) and the opposite surface (back surface). There is a method of adjusting the amount of the hydrophilic polymer to be applied, which is preferably used. In such a method, since the hydrophilic polymer shrinks due to a high temperature and a low relative humidity at the time of thermal development, curling occurs such that the surface coated with a large amount of the hydrophilic polymer is turned inside.

In the case of a single-sided photosensitive material having a photosensitive layer on one side of a support, when an ANSI curl value of +0.5 or more is obtained,
The ratio of the coating amount (g / m ² ) of the hydrophilic polymer between the photosensitive surface and the back surface was adjusted so that the ratio of the back surface / photosensitive surface was 1.05 / 1.0 to 5.0 /.
1.0, more preferably 1.1 / 1.0 to 2.5 / 1.0. On the other hand, A of -0.5 or less
In order to obtain the NSI curl value, the ratio of the amount of the hydrophilic polymer (g / m ² ) applied between the back surface and the photosensitive surface is set to 1.05 / 1.0 to 5.0 / 1. 0, and even 1.1
/1.0 to 2.5 / 1.0.

When there are photosensitive layers on both sides of the support,
As ANSI curl value is +0.5 or more, the coating amount of the hydrophilic polymer on one surface of the support and the (g / m ²⁾ and the coating amount of the hydrophilic polymer of the other surface (g / m ²⁾ Is 1.05 / 1.
0-5.0 / 1.0, further 1.1 / 1.0-2.5
/1.0 is preferable.

Examples of the hydrophilic polymer include gelatin and derivatives thereof, cellulosic polymers such as methylcellulose, carboxymethylcellulose, hydroxypropylcellulose and hydroxypropylmethylcellulose, polyvinyl alcohol and derivatives thereof, and polyacrylamide and derivatives thereof. In addition, even those which are not water-insoluble and can not be called hydrophilic polymers are -COOH, -OH,-
Relatively large polymer moisture absorption includes groups such as NH ₂ are available. Examples of such polymers include methyl methacrylate / acrylic acid copolymers and ethyl methacrylate / methacrylic acid copolymers.

The layer containing these polymers may be any of the photographic layers constituting the photothermographic material, and may be an intermediate layer, a surface protective layer, a back layer, a back surface protective layer, or the like. preferable.

The coating amount of the above hydrophilic polymer is the total amount when two or more photographic layers on one surface contain a hydrophilic polymer, but contains a hydrophilic polymer such as gelatin as a main binder. When the coating amount (g / m ² ) of the hydrophilic polymer in the photographic layer occupies 60% or more of the whole, the above-mentioned ratio is calculated by approximating the coating amount of only that layer to the coating amount of the whole (one side). You may.

The photothermographic material of the present invention is processed using an image recording apparatus for the photothermographic material.

FIG. 1 is a schematic view of an image recording apparatus for a photothermographic material used in the present invention. That is, the developing method of the present invention is carried out in such a heat developing section.

As shown in FIG. 1, the image exposure unit 10
A laser light source 1 for emitting a light beam 1a in a narrow band wavelength region according to the spectral sensitivity characteristics of the photothermographic material 8; It has a rotating polygonal mirror 3, which is an optical deflector, a scanning lens 7, and a mirror 9. The image exposure unit 10 further includes a recording control device for driving a laser light source, a collimator lens and a beam expander for shaping a light beam 1a emitted from the laser light source, a surface tilt correction optical system, and a mirror for adjusting an optical path. Various members arranged in a known light beam scanning device are arranged as necessary.

In the image exposure section 10, the light beam 1 a emitted from the laser light source 1 is deflected in the main scanning direction (perpendicular to the plane of FIG. 1) by the rotary polygon mirror 3, and is scanned by the scanning lens 7. The light is adjusted so as to form an image at a predetermined recording position 8, the optical path is changed by a mirror 9, and the light enters the predetermined recording position. At this time, the photothermographic material 8 is conveyed in a sub-scanning direction orthogonal to the main scanning fragrance while being held at a predetermined recording position by a pair of conveying rollers.

Since the light beam 1a having been subjected to pulse width modulation or the like according to the recorded image is deflected in the main scanning direction, the photothermographic material 8 is two-dimensionally scanned and exposed by the light beam. , The latent image is recorded.

As shown in FIG. 1, the photothermographic material 8 on which the latent image has been recorded in the image exposure section 10 is
The sheet is conveyed by the conveying roller pair 13 and conveyed to the thermal developing section 20.

FIG. 2 is a schematic view showing the vicinity of the heat drum 4 of the heat developing section 20.

As shown in FIGS. 1 and 2, the heat development section 20 heats the photothermographic material 8 to perform heat development to turn the latent image into a visible image. It has a heat drum 4 incorporated as a heating light source and an endless belt 6.

The heat drum 4 is formed of a metal such as stainless steel, the surface of which is heated and held at a temperature corresponding to the heat development temperature of the photothermographic material 8, and rotates around a shaft 4a. The photothermographic material 8 is pinched and conveyed together with the endless belt 6.

The endless belt 6 is stretched around four feed rollers 5 and is pressed so as to be wound around the heat drum 4.

As shown in FIG. 1, the photothermographic material 8 conveyed to the heat developing section 20 by the conveying roller pair is nipped and conveyed by the endless belt 6, between the heat drum 4 and the endless belt 6. While being carried in and being conveyed in accordance with the rotation of the heat drum 4, the latent image recorded by exposure is thermally developed by the heat drum 4 and recorded by exposure.

The photothermographic material 8 of the present invention has an absolute value of ANSI curl of 0.5 or more at the time of heat development, and as shown in FIG. 4 reaches a peeling position 4X on the photothermographic material 8
Is peeled off. As shown in FIG. 2, in the photothermographic material 8 after the peeling, the center axis of the heat drum 4 (that is, the center axis of the heat drum 4, that is, the surface formed by the tangent T ₁ at any point of the peeling position 4X of the heat drum 4) The photothermographic material 8 is conveyed onto the heat drum 4 so as to be subjected to thermal development so that the curl is drawn in a direction away from the shaft 4a) (upward in the illustrated example), that is, outwardly, so as to form an arc. in this case,
Center of curvature at any point curl curve and the center axis of the heating drum 4, located on opposite sides of the plane formed by the tangent line T ₁ of the above.

By transferring the photothermographic material and performing heat development in this manner, the passability of the photothermographic material is improved. On the other hand, if the sheet is conveyed so as to cause curl in the opposite direction to heat development, the passability may be poor.

More specifically, when the single-sided photosensitive material has an ANSI curl value of +0.5 or more, the material may be conveyed so that the back surface is in contact with the heat drum.
What is necessary is just to convey so that a photosensitive surface may contact a heat drum.
The double-sided photosensitive material may be conveyed according to the direction of curl during thermal development.

As shown in FIG. 2, the photothermographic material 8 peeled off from the heat drum 4 after the heat development is completed.
Is transported out of the apparatus in the direction of the arrow and is placed in a tray (not shown).
Is discharged.

The image exposure section and the heat development section of the image recording apparatus for a photothermographic material used in the present invention are not limited to those shown in the drawings, and may have various structures as long as the developing method of the present invention can be carried out. Good.

Next, the photosensitive layer of the photothermographic material of the present invention will be described. The photosensitive layer of the photothermographic material of the invention refers to a layer containing photosensitive silver halide among the layers constituting the photothermographic material of the invention. The photothermographic material of the present invention may have two or more photosensitive layers. The binder of the photosensitive layer of the photothermographic material of the present invention is not particularly limited, but is preferably a photosensitive layer containing the polymer latex described below in an amount of 50% by weight or more of the total binder.
However, the "polymer latex" referred to here is a water-insoluble hydrophobic polymer dispersed as fine particles in a water-soluble dispersion medium. The dispersion state is such that the polymer is emulsified in a dispersion medium, emulsion-polymerized, micelle-dispersed, or partially dispersed in polymer molecules and molecular chains themselves are molecularly dispersed. Any of them may be used.

The polymer latex of the present invention is described in "Synthetic Resin Emulsion" (edited by Tadashi Okuda and Hiroshi Inagaki, published by Kobunshi Kanko (1978)), "Application of Synthetic Latex (Takaaki Sugimura, Yasuo Kataoka, Soichi Suzuki, Edited by Keiji Kasahara, published by the Society of Polymer Publishing (1993)), and "Synthesis of Synthetic Latex (Souichi Muroi, published by the Society of Polymer Publishing (1970))". The average particle size of the dispersed particles is preferably in the range of 1 to 50,000 nm, more preferably in the range of about 5 to 1000 nm. There is no particular limitation on the particle size distribution of the dispersed particles, and they may have a wide particle size distribution or a monodispersed particle size distribution.

The polymer latex of the present invention may be a so-called core / shell type latex other than the polymer latex having a normal uniform structure. In this case, it may be preferable to change the glass transition temperature of the core and the shell.

The minimum film forming temperature (MFT) of the polymer latex of the present invention is -30 ° C to 90 ° C, more preferably 0 ° C.
The temperature is preferably about 70C. A film-forming auxiliary may be added to control the minimum film-forming temperature. The film forming aid is an organic compound (usually an organic solvent) which is also called a plasticizer and lowers the minimum film forming temperature of the polymer latex. For example, the above-mentioned "Synthetic Latex Chemistry (Souichi Muroi, published by Kobunshi Kankokai (1970)") )"It is described in.

The polymer used for the polymer latex of the present invention includes acrylic resin, vinyl acetate resin,
Examples thereof include a polyester resin, a polyurethane resin, a rubber-based resin, a vinyl chloride resin, a vinylidene chloride resin, a polyolefin resin, and a copolymer thereof.

The polymer may be a linear polymer, a branched polymer, or a crosslinked polymer. The polymer may be a so-called homopolymer in which a single monomer is polymerized, or a copolymer in which two or more monomers are polymerized. In the case of a copolymer, it may be a random copolymer or a block copolymer. The molecular weight of the polymer is 5,000 to 100,000 in number average molecular weight.
0, preferably about 10,000 to 100,000. If the molecular weight is too small, the mechanical strength of the photosensitive layer is insufficient, and if it is too large, the film-forming properties are poor, which is not preferable.

The polymer of the polymer latex used in the present invention has an equilibrium moisture content at 25 ° C. and 60% RH of 2% by weight or less, more preferably 1% by weight or less. This is preferable in terms of prevention and the like.
The lower limit of the equilibrium water content is not particularly limited, but is preferably about 0.01% by weight, more preferably 0.03% by weight.
%. For the definition and measurement method of the equilibrium moisture content,
For example, "Polymer Engineering Course 14, Polymer Material Testing Method (edited by the Society of Polymer Science, Jinjinshokan)" can be referred to. The actual measurement can be performed as shown in Examples below.

Specific examples of the polymer latex used as a binder for the photosensitive layer of the photothermographic material of the present invention include the following. Latex of methyl methacrylate / ethyl acrylate / methacrylic acid copolymer, latex of methyl methacrylate / 2 ethylhexyl acrylate / styrene / acrylic acid copolymer, latex of styrene / butadiene / acrylic acid copolymer, styrene / butadiene / divinylbenzene /
Latex of methacrylic acid copolymer, latex of methyl methacrylate / vinyl chloride / acrylic acid copolymer, latex of vinylidene chloride / ethyl acrylate / acrylonitrile / methacrylic acid copolymer and the like.

The polymer for such a polymer latex is also commercially available, and the following polymers can be used. For example, as an acrylic resin, Sebian A-46
35, 46583, 4601 (all manufactured by Daicel Chemical Industries, Ltd.), Nipol Lx811, 814, 82
0, 821, 857 (Nippon Zeon Co., Ltd.), etc.
As a polyester resin, FINETEX ES65
Examples of polyurethane resins such as 0, 611, 675, and 850 (both manufactured by Dainippon Ink and Chemicals, Inc.) and WD-size WMS (manufactured by Eastman Chemical) include HYDR.
Examples of rubber-based resins such as AN AP10, 20, 30, 40 (all manufactured by Dainippon Ink and Chemicals, Inc.) include LACSTA.
R7310K, 3307B, 4700H, 7132C
(Dai Nippon Ink Chemical Co., Ltd.), Nipol Lx
Examples of vinyl chloride resins such as 416, 410, 438C, and 2507 (all manufactured by Zeon Corporation) include G351,
G576 (all manufactured by Nippon Zeon Co., Ltd.); vinylidene chloride resins such as L502 and L513 (all manufactured by Asahi Kasei Kogyo Co., Ltd.); )
Manufactured).

These polymers may be used alone as a polymer latex, or may be used as a blend of two or more as required.

The polymer latex used in the present invention is preferably a styrene-diene copolymer latex, particularly preferably a styrene-butadiene copolymer latex. The molar ratio of the monomer unit of styrene to the monomer unit of butadiene in the styrene-butadiene copolymer is 50:50 to 95: 5, and more preferably 60:40 to 9.
It is preferably 0:10. Further, the proportion of the styrene monomer unit and the butadiene monomer unit in the copolymer is preferably 50 to 99% by weight, more preferably 60 to 97% by weight. The preferred molecular weight range is the same as described above.

Commercially available styrene-butadiene copolymers or latexes thereof include LACSTAR 33
07B, 7132C, Nipol Lx416 and the like are preferred.

The photosensitive layer of the present invention comprises 50% by weight of the total binder.
The above is the polymer derived from the polymer latex, and it is preferable that 70% by weight or more is the polymer derived from the polymer latex.

The photosensitive layer of the present invention may contain a hydrophilic polymer such as gelatin, polyvinyl alcohol, methylcellulose, hydroxypropylcellulose, carboxymethylcellulose, or hydroxypropylcellulose in the range of 50% by weight or less of the total binder, if necessary. good.
The amount of these hydrophilic polymers to be added is preferably 30% by weight or less of the total binder in the photosensitive layer.

The photosensitive layer of the present invention is formed by applying an aqueous coating solution and then drying it. However, the term "aqueous" used herein means that 30% by weight or more of the solvent (dispersion medium) of the coating liquid is water. As components other than water of the coating solution, methyl alcohol,
Ethyl alcohol, isopropyl alcohol, methyl cellosolve, ethyl cellosolve, dimethylformamide,
A water-miscible organic solvent such as ethyl acetate can be used.

Specific examples of the solvent composition include the following in addition to water. Water / methanol = 90 /
10, water / methanol = 70/30, water / ethanol =
90/10, water / isopropanol = 90/10, water /
Dimethylformamide = 95/5, water / methanol / dimethylformamide = 80/15/5, water / methanol / dimethylformamide = 90/5/5
wt%).

The total amount of the binder per one layer of the photosensitive layer of the present invention is 0.2 to 30 g / m ² in terms of the coating amount per 1 m ² of the photographic material.
m ² , more preferably in the range of 1 to 15 g / m ² . The thickness of each photosensitive layer is preferably from 0.3 to 50 μm, and more preferably from 1.5 to 30 μm.

In the photosensitive layer of the present invention, a reducing agent, an organic silver salt, a color tone agent, an antifoggant and the like may be added, if necessary, in addition to the photosensitive silver halide. Further, a dye for adjusting color tone, a cross-linking agent for cross-linking, a surfactant for improving coating properties, and the like may be added to the photosensitive layer of the present invention.

The method for forming the photosensitive silver halide in the present invention is well known in the art, for example, the method described in Research Disclosure No. 17029 of June 1978 and US Pat. No. 3,700,458 can be used. it can. 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 the white turbidity after image formation to be low.
μm or less, more preferably 0.01 μm or more and 0.15 μm or less,
More preferably, the thickness is 0.02 μm or more and 0.12 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 than normal crystals, for example, in the case of spherical grains, rod-shaped grains, etc., it refers to the diameter of a sphere equivalent to the volume of silver halide grains.

The shape of the silver halide grains is cubic,
Octahedral, tabular particles, spherical particles, rod-like particles, potato-like particles and the like can be mentioned. In the present invention, cubic particles and tabular particles are particularly preferable. When tabular silver halide grains are used, the average aspect ratio is preferably from 100: 1 to 2: 1, more preferably from 50: 1 to 3: 1. Further, grains having rounded corners of silver halide grains can also be preferably used. The surface index (mirror index) of the outer surface of the photosensitive silver halide grain is not particularly limited, but the spectral sensitization efficiency when the spectral sensitizing dye is adsorbed is high.
The proportion occupied by the {100} plane is preferably high. The ratio is preferably at least 50%, more preferably at least 65%, even more preferably at least 80%. The Miller index ratio of the {100} plane is determined by T. Tani; J. Imaging Sci., 29, 165 (198), which utilizes the adsorption dependence of the sensitizing dye on the {111} and {100} planes.
5 years). There is no particular limitation on the halogen composition of the photosensitive silver halide,
Silver chloride, silver chlorobromide, silver bromide, silver iodobromide, silver iodochlorobromide, any of silver iodide may be used, but in the present invention, silver bromide or silver iodobromide is preferred. Can be used. Particularly preferred is silver iodobromide, and the silver iodide content is preferably from 0.1 mol% to 40 mol%,
More preferably, it is not less than 20 mol% and not more than 20 mol%. 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. Preferably, silver halide grains having a core / shell structure can be used. As the structure, core / shell particles having preferably a 2- to 5-layer structure, more preferably a 2- to 4-layer structure, can be used.

The photosensitive silver halide grains of the present invention preferably contain at least one complex of a metal selected from rhodium, rhenium, ruthenium, osnium, iridium, cobalt, mercury or iron. One type of these metal complexes may be used, or two or more types of complexes of the same metal and different metals may be used in combination. The preferred content is in the range of 1 nmol to 10 mmol per mol of silver, preferably 10 mol.
More preferably, the range is from n mol to 100 μmol. As a specific structure of the metal complex, a metal complex having a structure described in JP-A-7-225449 or the like can be used. cobalt,
As the iron compound, a hexacyano metal complex can be preferably used. Specific examples include ferricyanate ion, ferrocyanate ion, hexacyanocobaltate ion, and the like, but are not limited thereto. Even if the content of the metal complex in the silver halide is uniform,
The core portion may be contained at a high concentration, or the shell portion may be contained at a high concentration, and there is no particular limitation.

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

The photosensitive silver halide grains in the present 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, compounds having a P = Te bond,
Tellurocarboxylates, Te-organyltellurocarboxylates, di (poly) tellurides, tellurides,
Tellurols, telluroacetals, tellursulfonates, compounds having a P-Te bond, Te-containing heterocycles, tellurocarbonyl compounds, inorganic tellurium compounds, colloidal tellurium, and the like can be used. Compounds preferably used in the noble metal sensitization method include, for example, chloroauric acid, potassium chloroaurate, potassium aurithiocyanate,
Gold sulfide, gold selenide, or US Patent 2,448,060
And the compounds described in British Patent No. 618,061 can be preferably used. Specific compounds of the reduction sensitization method include, as well as ascorbic acid, thiourea dioxide, for example, stannous chloride, aminoiminomethanesulfinic acid, hydrazine derivatives, borane compounds, silane compounds,
A polyamine compound or the like can be used. Reduction sensitization can be achieved by ripening the emulsion while maintaining the pH of the emulsion at 7 or more or the pAg at 8.3 or less. Further, reduction sensitization can be achieved by introducing a single addition portion of silver ion during grain formation.

The amount of the photosensitive silver halide used in the present invention is preferably 0.01 mol to 0.5 mol, more preferably 0.02 mol to 0.3 mol, and more preferably 0.03 mol to 1 mol of the organic silver salt. It is particularly preferably at least 0.25 mol and not more than 0.25 mol. Regarding the mixing method and the mixing conditions of the separately prepared photosensitive silver halide and organic silver salt, the prepared silver halide particles and organic silver salt are mixed with a high-speed stirrer, ball mill, sand mill, colloid mill, vibration mill, homogenizer, etc. There is a method of mixing, or a method of preparing an organic silver salt by mixing photosensitive silver halide prepared at any timing during the preparation of the organic silver salt, etc. There is no particular limitation as long as it appears.

As the silver halide preparation method of the present invention, a so-called halation method in which a part of silver of an organic silver salt is halogenated with an organic or inorganic halide is also preferably used. The organic halide used here may be any compound as long as it is a compound which reacts with an organic silver salt to form a silver halide.N-halogenoimides (e.g., N-bromosuccinimide), quaternary nitrogen compounds (e.g. Tetrabutylammonium bromide), quaternary nitrogen halide and associated halogen molecules (pyridinium bromide perbromide)
And the like. As the inorganic halogen compound, any compound can be used as long as it reacts with an organic silver salt to generate silver halide, and an alkali metal or ammonium halide (such as sodium chloride, lithium bromide, potassium iodide, ammonium bromide, etc.) ), Alkaline earth metal halides (calcium bromide, magnesium chloride, etc.), transition metal halides (ferric chloride, cupric bromide, etc.), metal complexes with halogen ligands (sodium iridium bromide) , Ammonium rhodate, etc.) and halogen molecules (bromine, chlorine, iodine). Further, a desired organic / inorganic halide may be used in combination.

In the present invention, the amount of the halide to be added is preferably 1 mmol to 500 mmol, more preferably 10 mmol to 25 mmol, as a halogen atom per 1 mol of the organic silver salt.
0 mmol is more preferred.

The organic silver salt that can be used in the present invention is
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,
In particular, a silver salt of a long-chain fatty carboxylic acid (having 10 to 30 carbon atoms, preferably 15 to 28 carbon atoms) is preferred. Complexes of organic or inorganic silver salts whose ligands have a complex stability constant in the range of 4.0 to 10.0 are also preferred. The silver donor material is preferably about 5% of the imaging layer.
Up to 30% by weight. Preferred organic silver salts include silver salts of organic compounds having a carboxyl group. Examples of these include, but are not limited to, silver salts of aliphatic carboxylic acids and silver salts of aromatic carboxylic acids.
Preferred examples of the silver salt of the aliphatic carboxylic acid include silver behenate, silver arachidate, silver stearate, silver oleate, silver laurate, silver caproate, silver myristate, silver palmitate, silver maleate, and fumarate. Silver acid, silver tartrate,
Silver linoleate, silver butyrate and silver camphorate, and mixtures thereof.

Silver salts of compounds containing a mercapto group or a thione group and derivatives thereof can also be used.
Preferred examples of these compounds include 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- (ethylglycolamide) benzothiazole, S-alkylthioglycolic acid (where the alkyl group has 12 carbon atoms)
A silver salt of thioglycolic acid, such as a silver salt of
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, for example silver salts of 1,2,4-mercaptothiazole derivatives such as silver salts of 3-amino-5-benzylthio-1,2,4-thiazole;
Silver salts of thione compounds such as the silver salt of 3- (3-carboxyethyl) -4-methyl-4-thiazoline-2-thione described in U.S. Pat. No. 3,301,678. Furthermore, compounds containing an imino group can also be used. Preferred examples of these compounds include silver salts of benzotriazole and derivatives thereof, for example, silver salts of benzotriazole such as silver methylbenzotriazole, silver salts of halogen-substituted benzotriazole such as silver 5-chlorobenzotriazole, and US Pat. 4,220,709, such as silver salts of 1,2,4-triazole or 1-H-tetrazole, and silver salts of imidazole and imidazole derivatives. For example, U.S. Pat.
Various silver acetylide compounds such as those described in 761,361 and 4,775,613 can also be used.

The shape of the organic silver salt that can be used in the present invention is not particularly limited, but a needle crystal having a short axis and a long axis is preferable. In the present invention, the minor axis is 0.01 μm or more.
20 μm or less, major axis 0.10 μm or more and 5.0 μm or less, minor axis 0.01 μm or more and 0.15 μm or less, major axis 0.10 μm or more
It is more preferably 4.0 μm or less. The particle size distribution of the organic silver salt is preferably monodispersed. Monodispersion means that the percentage of the value obtained by dividing the standard deviation of the length of each of the minor axis and major axis by the minor axis and major axis is preferably 100% or less, more preferably 80% or less, and still more preferably 50% or less. is there. The shape of the organic silver salt can be measured from a transmission electron microscope image of the organic silver salt dispersion. As another method of measuring monodispersity, there is a method of obtaining the standard deviation of the volume-weighted average diameter of the organic silver salt, and the percentage of the value divided by the volume-weighted average diameter (coefficient of variation) is preferably 100% or less,
It is more preferably at most 80%, further preferably at most 50%. As a measurement method, for example, the particle size (volume weighted average diameter) obtained by irradiating a laser beam to an organic silver salt dispersed in a liquid and obtaining an autocorrelation function with respect to the time change of fluctuation of the scattered light is obtained. Can be.

The organic silver salt that can be used in the present invention is
Preferably, desalting can be performed. The method for desalting is not particularly limited, and a known method can be used. However, a known filtration method such as centrifugal filtration, suction filtration, ultrafiltration, and floc forming water washing by a coagulation method can be preferably used. .

For the purpose of obtaining fine particles having a small particle size and no aggregation, a method of preparing a solid fine particle dispersion using a dispersant is used for the organic silver salt which can be used in the present invention. The method of dispersing the organic silver salt into solid fine particles is carried out by using a known fine means (for example, a ball mill, a vibrating ball mill, a planetary ball mill, a sand mill, a colloid mill, a jet mill, a roller mill) in the presence of a dispersing agent. Can be dispersed.

When the organic silver salt is formed into solid fine particles using a dispersant, for example, polyacrylic acid, a copolymer of acrylic acid, a maleic acid copolymer, a maleic acid monoester copolymer, and acryloylmethyl Synthetic anionic polymers such as propane sulfonic acid copolymer, semi-synthetic anionic polymers such as carboxymethyl starch and carboxymethyl cellulose, anionic polymers such as alginic acid and pectic acid, JP-A-52-92716, WO88 / 04794, etc. Anionic surfactant described, the compound described in Japanese Patent Application No. 7-350753, or known anionic, nonionic,
Cationic surfactants and other known polymers such as polyvinyl alcohol, polyvinylpyrrolidone, carboxymethylcellulose, hydroxypropylcellulose, and hydroxypropylmethylcellulose, or high-molecular compounds existing in nature such as gelatin can be appropriately selected and used. .

It is a general method that the dispersing aid is mixed with the organic silver salt powder or the organic silver salt in a wet cake state before the dispersion and then sent as a slurry to the dispersing machine. Heat treatment or treatment with a solvent may be performed in the combined state to obtain an organic silver salt powder or a wet cake. The pH may be controlled by a suitable pH adjuster before, during or after dispersion.

Instead of mechanically dispersing, fine particles may be formed by coarsely dispersing in a solvent by controlling the pH and then changing the pH in the presence of a dispersing aid. At this time, an organic solvent may be used as a solvent used for the coarse dispersion, and the organic solvent is usually removed after the completion of the fine particle formation.

The prepared dispersion is stored with stirring for the purpose of suppressing sedimentation of fine particles during storage, or stored in a highly viscous state (for example, in a jelly state using gelatin) with a hydrophilic colloid. You can also do.
Further, a preservative can be added for the purpose of preventing the propagation of various bacteria during storage.

[0074] The organic silver salt of the present invention can be used in a desired amount, preferably 0.1-5 g / m ² indicates an amount per photographic material 1 m ^2, more preferably is 1 to 3 g / m ² .

The reducing agent for the organic silver salt may be any substance which 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 preferably contained in an amount of 5 to 50% (mole), more preferably 10 to 40% (mole), based on 1 mol of silver on the surface having the image forming layer. The layer to which the reducing agent is added may be any layer on the side having the image forming layer. When it is added to a layer other than the image forming layer, it is preferable to use a relatively large amount of 10 to 50% (mol) with respect to 1 mol of silver. Further, the reducing agent may be a so-called precursor which is derivatized so as to have a function effectively only during development.

In a photothermographic material utilizing an organic silver salt, a wide range of reducing agents are disclosed in JP-A-46-6074 and JP-A-47-1238.
No. 47-33621, No. 49-46427, No. 49-115540, No.
50-14334, 50-36110, 50-147711, 51-326
No. 32, No. 51-1023721, No. 51-32324, No. 51-51933,
52-84727, 55-108654, 56-146133, 57
-82828, 57-82829, JP-A-6-3793, U.S. Pat.
667,9586, 3,679,426, 3,751,252, 3,75
No. 1,255, No. 3,761,270, No. 3,782,949, No. 3,839,
No. 048, 3,928,686, 5,464,738, German patent 23
No. 21328 and European Patent No. 692732. For example, amide oximes such as phenylamidooxime, 2-thienylamidooxime and p-phenoxyphenylamidooxime; azines such as 4-hydroxy-3,5-dimethoxybenzaldehydeazine; 2,2-bis (hydroxymethyl) propionyl- a combination of an aliphatic carboxylic acid arylhydrazide and ascorbic acid such as a combination of β-phenylhydrazine and ascorbic acid; a combination of polyhydroxybenzene and hydroxylamine, reductone and / or hydrazine (eg, hydroquinone and bis (ethoxyethyl) ) Hydroxylamine, piperidinohexose reductone or formyl-4
-Hydroxamic acids such as phenylhydroxamic acid, p-hydroxyphenylhydroxamic acid and β-alinine hydroxamic acid; combinations of azine and sulfonamidophenol (for example, phenothiazine and 2,6-dichloro-). 4-benzenesulfonamidophenol, etc.); ethyl-α-cyano-2-
Α-cyanophenylacetic acid derivatives such as methylphenylacetate and ethyl-α-cyanophenylacetate; 2,
2-dihydroxy-1,1-binaphthyl, 6,6-dibromo-2,2-
Bis-β- as exemplified by dihydroxy-1,1-binaphthyl and bis (2-hydroxy-1-naphthyl) methane
Naphthol; a combination of bis-β-naphthol and a 1,3-dihydroxybenzene derivative (eg, 2,4-dihydroxybenzophenone or 2,4-dihydroxyacetophenone); 3-methyl-1-phenyl-5-pyrazolone, Five-
Pyrazolones; reductones as exemplified by dimethylaminohexose reductone, anhydrodihydroaminohexose reductone and anhydrodihydropiperidone hexose reductone; 2,6-dichloro-4-benzenesulfonamidophenol and p- Sulfonamidophenol reducing agents such as benzenesulfonamidophenol; 2-phenylindane-1,3-dione; chromanes such as 2,2-dimethyl-7-t-butyl-6-hydroxychroman; 2,6-dimethoxy- 1,4-dihydropyridines such as 3,5-dicarbethoxy-1,4-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,
And aldehydes and ketones such as benzyl and biacetyl; 3-pyrazolidone and certain indan-1,3-diones; chromanol (such as tocopherol). Particularly preferred reducing agents are bisphenol and chromanol.

The reducing agent of the present invention may be added by any method such as a solution, a powder, and a dispersion of solid fine particles. The dispersion of the solid fine particles is carried out by a known means for making fine (for example, a ball mill, a vibration ball mill, a sand mill, a colloid mill, a jet mill, a roller mill, etc.). When dispersing the solid fine particles, a dispersing aid may be used.

When an additive known as a "toning agent" for improving an image is contained, the optical density may be increased. The toning agent may also be advantageous in forming a black silver image. The toning agent is preferably contained in an amount of 0.1 to 50% (mol) per mol of silver on the surface having the image forming layer, and more preferably 0.5 to 20% (mol). Further, the toning agent may be a so-called precursor which is derivatized so as to have a function effectively only during development.

In a photothermographic material utilizing an organic silver salt, a wide range of color toning agents are disclosed in JP-A-46-6077 and JP-A-47-10282.
Nos. 49-5019, 49-5020, 49-91215, 49
-91215, 50-5024, 50-32927, 50-67132
No. 50-67641, No. 50-114217, No. 51-3223, No. 5
1-27923, 52-14788, 52-99813, 53-1020
No. 53-76020, No. 54-156524, No. 54-156525,
No. 61-183642, JP-A-4-56848, JP-B-49-10727
No. 54-20333, U.S. Pat.Nos. 3,080,254, 3,446,64
No. 8, 3,782,941, 4,123,282, 4,510,236
And British Patent 1380795 and Belgian Patent 841910. Examples of toning agents are phthalimide and N-
Hydroxyphthalimide; succinimide, pyrazoline
And cyclic imides such as quinazolinone, 3-phenyl-2-pyrazolin-5-one, 1-phenylurazole, quinazoline and 2,4-thiazolidinedione; naphthalimides (eg, N-hydroxy-1 , 8-naphthalimide); cobalt complex (eg, cobalt hexamine trifluoroacetate); 3-mercapto-1,2,4-triazole, 2,4-dimercaptopyrimidine, 3-mercapto-4,5
N- (aminomethyl) aryldicarboximides; mercaptans exemplified by -diphenyl-1,2,4-triazole and 2,5-dimercapto-1,3,4-thiadiazole;
(For example, (N, N-dimethylaminomethyl) phthalimide and N, N- (dimethylaminomethyl) -naphthalene-2,3-
Dicarboximides); and blocked pyrazoles, isothiuronium derivatives and certain photobleaching agents (
For example, 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-benzothiazolinylidene) -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-phthalazinedione A combination of phthalazinone and a phthalic acid derivative (for example, phthalic acid, 4-methylphthalic acid, 4-nitrophthalic acid and tetrachlorophthalic anhydride); phthalazine, a phthalazine derivative or a metal salt, or 4- (1-naphthyl) ) Derivatives such as phthalazine, 6-chlorophthalazine, 5,7-dimethoxyphthalazine and 2,3-dihydrophthalazine; phthalazine and phthalic acid derivatives (for example, phthalic acid,
Quinazolinedione, such as 4-methylphthalic acid, 4-nitrophthalic acid and tetrachlorophthalic anhydride);
Benzoxazine or naphthoxazine derivatives; rhodium complexes that function not only as color tone regulators but also in-situ as sources of halide ions for silver halide formation, such as ammonium hexachlororhodate (III), rhodium bromide, rhodium nitrate And potassium hexachlororhodate (III); inorganic peroxides and persulfates, such as ammonium disulfide and hydrogen peroxide; 1,3-benzoxazine-2,4-dione, 8-methyl
-1,3-benzoxazine-2,4-dione and 6-nitro-
Benzoxazine-2,4-dione such as 1,3-benzoxazine-2,4-dione; pyrimidine and asymmetric triazine (for example, 2,4-dihydroxypyrimidine, 2-hydroxy-4-aminopyrimidine and the like), Azauracil and tetraazapentalene derivatives (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).

The color tone agent of the present invention may be added by any method such as a solution, a powder, and a solid fine particle dispersion. The dispersion of the solid fine particles is carried out by a known means for making fine (for example, a ball mill, a vibration ball mill, a sand mill, a colloid mill, a jet mill, a roller mill, etc.). When dispersing the solid fine particles, a dispersing aid may be used.

As the sensitizing dye in the present invention, any dye can be used 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, a cyanine dye, a merocyanine dye, a complex cyanine dye, a complex merocyanine dye, a holopolar cyanine dye, a styryl dye, a hemicyanine dye, an oxonol dye, a hemioxonol dye, and the like can be used. Useful sensitizing dyes for use in the present invention include, for example, RESEARCH DISCLOSURE Item 17
Section 643IV-A (p.23, December 1978), Item 1831X (1979)
August, p. 437). Especially various laser imagers, scanners,
A sensitizing dye having a spectral sensitivity suitable for the spectral characteristics of a light source of an image setter or a plate making camera can be advantageously selected.

As an example of spectral sensitization to red light, He-Ne
For so-called red light sources such as lasers, red semiconductor lasers and LEDs, compounds of I-1 to I-38 described in JP-A-54-18726, and compounds of I-1 described in JP-A-6-75322 are disclosed. I
-35 and the compounds I-1 to I-34 described in JP-A-7-287338, and the dye 1 described in JP-B-55-39818.
20, compounds of I-1 to I-37 described in JP-A-62-284343 and compounds of I-1 to I-34 described in JP-A-7-287338 are advantageously selected.

For semiconductor laser light sources in the wavelength region of 750 to 1400 nm, various known dyes including cyanine, merocyanine, styryl, hemicyanine, oxonol, hemioxonol and xanthene dyes are spectrally advantageously sensitized. Can be done. 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 include, in addition to the above basic nuclei, acidic nuclei such as thiohydantoin nucleus, rhodanine nucleus, oxazolidinedione nucleus, thiazolinedione nucleus, barbituric acid nucleus, thiazolinone nucleus, malononitrile nucleus and pyrazolone nucleus. Including. Among the above cyanine and merocyanine dyes, those having an imino group or a carboxyl group are particularly effective. For example, U.S. Pat.
3,719,495 and 3,877,943, UK Patent 1,466,201
No. 1,469,117, No. 1,422,057, Tokuhei 3-10391
No., 6-52387, JP-A-5-341432, 6-94781,
It may be appropriately selected from known dyes as described in JP-A-6-301141.

Particularly preferred as the structure of the dye used in the present invention is a cyanine dye having a thioether bond-containing substituent (for example, JP-A Nos. 62-58239 and 3-1386).
No.38, No.3-138642, No.4-255840, No.5-72659, No.
5-72661, 6-222491, 2-230506, 6-258757
No., 6-317868, 6-324425, Tokuyohei 7-500926,
Dyes described in U.S. Pat.No. 5,541,054), dyes having a carboxylic acid group (for example, JP-A-3-163440, 6-30
1141, No. 5,441,899), merocyanine dyes, polynuclear merocyanine dyes and polynuclear cyanine dyes (JP-A-47-6329, JP-A-49-105524, JP-A-51-12771).
No. 9, No. 52-80829, No. 54-61517, No. 59-214846,
Nos. 60-6750, 63-159841, JP-A-6-35109,
No. 6-59381, No. 7-16537, No. 7-46537, Tokiohei 55-50
No. 111, British Patent 1,467,638 and U.S. Pat. No. 5,281,515).

As dyes forming a J-band, the dyes described in Example 5 of US Pat. Nos. 5,510,236 and 3,871,887, JP-A-2-96131, and JP-A-59-48753 are disclosed. It can be preferably used in the invention.

These sensitizing dyes may be used alone.
Two or more kinds may be used in combination. Combinations of sensitizing dyes are often used, especially for supersensitization. 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
Research Disclosure Volume 176 17643 (Issued December 1978) 2
Section J on page 3, IV, or JP-B-49-25500, 43-4933
And JP-A-59-19032 and JP-A-59-192242.

The sensitizing dyes used in the present invention may be used in combination of two or more. 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-
It may be dissolved in a solvent such as methoxy-2-propanol or N, N-dimethylformamide alone or in a mixed solvent and added to the emulsion.

Further, as disclosed in US Pat. No. 3,469,987, a dye is dissolved in a volatile organic solvent, this solution is dispersed in water or a hydrophilic colloid, and this dispersion is dispersed in an emulsion. Method of adding to Japanese Patent Publication No. 44-23389,
As disclosed in JP-A-44-27555 and JP-A-57-22091, a dye is dissolved in an acid and this solution is added to the emulsion, or an acid or base is added to the emulsion as an aqueous solution in the presence of an acid or base. A method of adding an aqueous solution or a colloidal dispersion in the presence of a surfactant to a emulsion as disclosed in U.S. Patent Nos. 3,822,135 and 4,006,025, Japanese Patent Application Laid-Open No. Sho 51 (1991) discloses a method in which a dye is directly dispersed in a hydrophilic colloid and the dispersion is added to an emulsion as disclosed in JP-A-102733 and JP-A-58-105141.
As disclosed in JP-A-74624, a method in which a dye is dissolved using a compound that causes red shift, and this solution is added to an emulsion can also be used. Also, ultrasonic waves can be used for dissolution.

The sensitizing dye to be used in the present invention may be added to the silver halide emulsion of the present invention at any time during the preparation of the emulsion which has been found to be useful. For example, U.S. Pat.Nos. 2,735,766 and 3,628,960
No. 4,183,756, No. 4,225,666, JP-A-58-18414
As disclosed in the specifications of JP-A Nos. 2 and 60-196749, chemical ripening is carried out during the step of forming silver halide grains and / or before desalting, during and / or after desalting. Before the start of the emulsion, as disclosed in the specification of JP-A-58-113920, etc., immediately before or during the process of chemical ripening, after the chemical ripening, and before the application of the emulsion before the coating. If so, it may be added at any time in the process. Also, as disclosed in the specification of U.S. Pat.No. 4,225,666, JP-A-58-7629, etc., the same compound may be used alone or in combination with a compound having a different structure, for example, during the particle forming step and the chemical ripening step. May be added separately during or after chemical ripening, or before or after chemical ripening, and may be added separately. May be added.

The amount of the sensitizing dye used in the present invention may be a desired amount in accordance with the performance such as sensitivity and fog.
The amount is preferably from 10 ^-6 to 1 mol, more preferably from 10 ^-4 to 10 ^-1 mol, per mol of silver halide in the photosensitive layer.

The silver halide emulsion according to the present invention or /
And the organic silver salts can be further protected against the formation of additional fog by antifoggants, stabilizers and stabilizer precursors, and can be stabilized against reduced sensitivity during storage in inventory. Suitable antifoggants, stabilizers and stabilizer precursors which can be used alone or in combination are the thiazonium salts described in U.S. Pat.Nos. 2,131,038 and 2,694,716, U.S. Pat.Nos. 2,886,437 and 2,444,6
Azaindene described in No. 05, mercury salt described in U.S. Pat.No. 2,728,663, urazole described in U.S. Pat.No. 3,287,135, sulfocatechol described in U.S. Pat.No.3,235,652,
Oxime described in British Patent No. 623,448, nitrone, nitroindazole, polyvalent metal salt described in U.S. Pat.No. 2,839,405, thyuronium salt described in U.S. Pat.No.3,220,839,
And palladium, platinum and gold salts described in U.S. Pat.Nos. 2,566,263 and 2,597,915, U.S. Pat.
And the halogen-substituted organic compounds described in 4,442,202, U.S. Pat.Nos. 4,128,557 and 4,137,079, 4,13
No. 8,365 and 4,459,350, and the phosphorus compounds described in U.S. Pat. No. 4,411,985.

The antifoggant preferably used in the present invention is an organic halide, for example, as described in JP-A-50-119624.
No. 50-120328, No. 51-121332, No. 54-58022, No.
56-70543, 56-99335, 59-90842, 61-12964
No. 2, 62-129845, JP-A-6-208191, 7-5621,
7-2781, 8-15809, U.S. Pat.
000 and 5464737.

The antifoggant of the present invention may be added by any method such as a solution, a powder or a solid fine particle dispersion. The dispersion of the solid fine particles is carried out by a known means for making fine (for example, a ball mill, a vibration ball mill, a sand mill, a colloid mill, a jet mill, a roller mill, etc.). When dispersing the solid fine particles, a dispersing aid may be used.

Although not required to practice the present invention,
It may be advantageous to add a mercury (II) salt as an antifoggant to the emulsion layer. Preferred mercury (II) salts for this purpose are
Mercury acetate and mercury bromide. The amount of mercury used in the present invention is preferably in the range of 1 nmol to 1 mmol, more preferably in the range of 10 nmol to 100 μmol, per mol of silver applied.

The photothermographic material of the present invention may contain benzoic acids for the purpose of increasing the sensitivity and preventing fog. The benzoic acids of the present invention may be any benzoic acid derivative,
Examples of preferred structures are described in U.S. Pat.
4,152,160, Japanese Patent Application Nos. 8-151242, 8-151241, 8-9
8051 and the like. The benzoic acid of the present invention may be added to any part of the photothermographic material. However, it is preferable to add the benzoic acid to the layer having the photosensitive layer, and it is preferable to add the benzoic acid to the organic silver salt-containing layer. preferable. The benzoic acid of the present invention may be added at any time during the preparation of the coating solution, and when it is added to the organic silver salt-containing layer, it may be added at any time from the preparation of the organic silver salt to the preparation of the coating solution. It is preferable after salt preparation and immediately before application. As a method for adding the benzoic acids of the present invention, powder,
Any method such as a solution or a fine particle dispersion may be used.
Further, it may be added as a solution mixed with other additives such as a sensitizing dye, a reducing agent and a color tone agent. The benzoic acids of the present invention may be added in any amount, but may be added in an amount of 1 per mole of silver.
It is preferably from μmol to 2 mol, more preferably from 1 mmol to 0.5 mol.

In the present invention, a mercapto compound, a disulfide compound and a thione compound are contained in order to suppress or accelerate the development to control the development, to improve the spectral sensitization efficiency, to improve the storage stability before and after the development, and the like. be able to.

When a mercapto compound is used in the present invention, it may have any structure, but it may be Ar-SM, Ar-SSA
Those represented by r are preferred. In the formula, M is a hydrogen atom or an alkali metal atom, and Ar is an aromatic ring group or a condensed aromatic ring group having one or more nitrogen, sulfur, oxygen, selenium or tellurium atoms. Preferably, the heteroaromatic ring in these groups is benzimidazole, naphthimidazole, benzothiazole, naphthothiazole, benzoxazole, naphthoxazole, benzoselenazole, benzotellurazole, imidazole, oxazole, pyrazole, triazole, thiadiazole, tetrazole, triazine. , Pyrimidines, pyridazines, pyrazines, pyridines, purines, quinolines or quinazolinones. This heteroaromatic ring is, for example, halogen
(E.g., Br and Cl), hydroxy, amino, carboxy, alkyl (e.g., one or more carbon atoms, preferably
Having from 1 to 4 carbon atoms) and alkoxy (e.g., one or more carbon atoms, preferably having from 1 to 4 carbon atoms) a substituent group consisting of Is also good. As mercapto-substituted heteroaromatic compounds, 2-mercaptobenzimidazole, 2-mercaptobenzoxazole, 2-mercaptobenzothiazole,
2-mercapto-5-methylbenzimidazole, 6-ethoxy-2-mercaptobenzothiazole, 2,2'-dithiobis-
Benzothiazole, 3-mercapto-1,2,4-triazole, 4,5-diphenyl-2-imidazolethiol, 2-mercaptoimidazole, 1-ethyl-2-mercaptobenzimidazole, 2-mercaptoquinoline, 8-mercaptopurine , 2-mercapto-4 (3H) -quinazolinone, 7-trifluoromethyl-4-quinolinethiol, 2,3,5,6-tetrachloro-
4-pyridinethiol, 4-amino-6-hydroxy-2-mercaptopyrimidine monohydrate, 2-amino-5-mercapto-1,3,4-thiadiazole, 3-amino-5-mercapto-1,
2,4-Triazole, 4-Hydrocyr-2-mercaptopyrimidine, 2-mercaptopyrimidine, 4,6-diamino-2-mercaptopyrimidine, 2-mercapto-4-methylpyrimidine hydrochloride, 3-mercapto-5-phenyl- Examples thereof include 1,2,4-triazole and 2-mercapto-4-phenyloxazole, but the present invention is not limited thereto.

The amount of the mercapto compound to be added is 0.001 to 1.0 per mol of silver in the emulsion layer which is the image forming layer.
A range of 0 moles is preferred, more preferably 0.01 to 0.3 moles per mole of silver.

Next, the photothermographic material of the present invention may be provided with a non-photosensitive layer. The non-photosensitive layer binder of the present invention is not particularly limited. As the polymer for the binder, for example, polymers such as gelatin, polyvinyl alcohol, casein, agar, acacia, hydroxyethyl cellulose, cellulose acetate, cellulose acetate butyrate, polyvinyl chloride, polymethacrylic acid, polyvinylidene chloride, and polyvinyl acetate are used. be able to.

Of these, hydrophilic polymers are preferable, and 30 wt% or more of the binder is preferably a hydrophilic polymer, and gelatin is most preferable as the hydrophilic polymer. Gelatin may be any one such as lime-processed gelatin and acid-processed gelatin. Further, a gelatin derivative may be used. As the binder of the non-photosensitive layer of the present invention, a latex of a polymer such as ethyl acrylate may be added in addition to the hydrophilic polymer.

The thickness of the non-photosensitive layer of the present invention is preferably 0.1 to 0.3.
The range is preferably from 1 to 10 μm, more preferably from 0.5 to 5 μm.

The non-photosensitive layer of the present invention is preferably formed by applying the above-mentioned aqueous coating solution and then drying it.

The non-photosensitive layer of the present invention may contain, if necessary, an organic silver salt, a reducing agent for the organic silver salt, a colorant, an antifoggant, a matting agent, a dye, a sliding agent, a surfactant and the like. You may.

In the photothermographic material of the present invention, a back layer (backing layer) may be provided on the surface of the support opposite to the surface on which the photosensitive layer is coated.

The binder for the back layer of the present invention is not particularly limited, and the polymers described for the binder for the photosensitive layer and the non-photosensitive layer can be used. Further, as a binder, the polymer latex described for the photosensitive layer, particularly at 25 ° C.
The use of a latex of a polymer having an equilibrium water content at 60% RH of 2% by weight or less is preferred.

The back layer of the present invention is preferably formed by applying and drying the above-mentioned aqueous coating solution.

In the present invention, the back layer preferably has a maximum absorption of 0.3 or more and 2 or less, more preferably 0.5 or more and 2 or less in a desired wavelength range.
In addition, the absorption in the visible region after the treatment is preferably 0.001 or more and less than 0.5, and more preferably a layer having an optical density of 0.001 or more and less than 0.3.

The back layer of the present invention may further contain a surfactant, a cross-linking agent, a sliding agent, and the like, if necessary.
U.S. Pat. Nos. 4,460,681 and 4,374,921
Backing resistive heating layer (backing resisti
ve heating layer) can be provided.

The thickness of the back layer of the present invention is 0.1 to 20 μm.
m, more preferably 0.5 to 10 μm.

The photothermographic material of the present invention may have a protective layer (back surface protective layer) on the back layer. The binder for the back surface protective layer is not particularly limited, and the polymers described for the non-photosensitive layer of the present invention can be used. Among them, hydrophilic polymers are particularly preferable. The back protective layer of the present invention is also preferably formed by applying and drying the above-mentioned aqueous coating solution.

A matting agent, a dye, a sliding agent, a surfactant and the like may be added to the back surface protective layer of the present invention, if necessary.

The back surface protective layer of the present invention has a thickness of 0.1 to 0.1.
The range is preferably 10 μm, more preferably 0.5 to 5 μm.

As the matting agent used in the photothermographic material of the present invention, fine particles such as polystyrene, polymethyl methacrylate and silica are preferable. The shape of the particles is not particularly limited, but spherical fine particles are preferred. The particle size of the matting agent is 0.2 to 20 µm, more preferably 0.5 to 10 µm.
It is preferably about μm. The addition amount of the matting agent layer constitution of the photothermographic material, can not be said unconditionally by the thickness and the intended use, shows a coating amount per photographic material 1 m ² 10 to 200 mg / m
² , more preferably about ²⁰ to 100 mg / m ² .

As the sliding agent used for the non-photosensitive layer, compounds known in the art such as silicone compounds and paraffin may be used. The addition amount of the slipping agent cannot be determined unconditionally depending on the layer constitution, the thickness and the purpose of use of the photothermographic material.
It is preferably about 400 mg / m ² , more preferably about ²⁰ to 200 mg / m ² .

As the crosslinking agent used in the photothermographic material of the present invention, known crosslinking agents such as epoxy compounds, isocyanate compounds and melamine compounds can be used. When the binder is gelatin, a cross-linking agent known in the field of photographic materials can be used. The amount of the crosslinking agent is usually 0.1 to 20% by weight of the binder, more preferably 1 to 1%.
0% by weight is preferred.

In the present invention, the matte degree of the back surface is preferably a Beck smoothness of 250 seconds or less and 10 seconds or more.
Further, the time is preferably 180 seconds or less and 50 seconds or more.

The light-sensitive material of the present invention comprises an antistatic or conductive layer, for example, a soluble salt (eg, chloride, nitrate, etc.), a vapor-deposited metal layer, US Pat. No. 2,861,056 and US Pat.
It may have a layer containing an ionic polymer as described in US Pat. No. 206,312 or an insoluble inorganic salt as described in US Pat. No. 3,428,451.

A method for obtaining a color image using the photothermographic material of the present invention is described in JP-A-7-13295, page 10, left column.
There is a method described from line 43 to page 11, left column, line 40. Also,
British Patent 1,326,889 as stabilizer for color dye images
Nos. 3,432,300, 3,698,909, 3,574,
Nos. 627, 3,573,050, 3,764,337 and 4,04
No. 2,394.

The layers constituting the photothermographic material of the present invention can be coated by various 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. Can be. If desired, U.S. Pat.No. 2,761,791 and British Patent 837,095
Two or more layers can be simultaneously coated by the method described in the above item.

Additional layers in the photothermographic material of the present invention, such as a dye-receiving layer for receiving a moving dye image, an opaque layer if reflective printing is desired, a protective topcoat layer and photothermographic techniques It may include a known primer layer and the like. The light-sensitive material of the present invention is preferably capable of forming an image with only one light-sensitive material, and it is preferable that a functional layer necessary for image formation such as an image receiving layer does not become another light-sensitive material.

The light-sensitive material of the present invention may be developed by any method, but is usually developed by raising the temperature of the light-sensitive material exposed imagewise. The preferred development temperature is 80 to
The temperature is 250 ° C, more preferably 100 to 140 ° C.
The development time is preferably from 1 to 180 seconds, more preferably from 10 to 90 seconds.

The light-sensitive material of the present invention may be exposed by any method, but a laser beam is preferred as an exposure light source.
As the laser beam according to the present invention, gas laser, YAG
Lasers, dye lasers, semiconductor lasers and the like are preferred. Further, a semiconductor laser and a second harmonic generation element can be used.

The light-sensitive material of the present invention has a low haze at the time of exposure and tends to cause interference fringes. Examples of this interference fringe prevention technology include a technology for obliquely entering a laser beam into a photosensitive material as disclosed in JP-A-5-113548 and a multi-mode laser disclosed in WO95 / 31754 and the like. There is known a method of utilizing these techniques, and it is preferable to use these techniques.

Various supports can be used for the photothermographic material of the present invention. Typical supports include polyethylene terephthalate film, polyethylene naphthalate film, cellulose nitrate film, cellulose ester film, polyvinyl acetal film, polycarbonate film as well as glass, paper, metal and the like. Further, Japanese Patent Application Laid-Open Nos.
A support of a styrenic copolymer as disclosed in Japanese Patent No. 54386 may be used. Among them, biaxially stretched polyethylene terephthalate is preferred in terms of strength, dimensional stability, chemical resistance and the like. The support may be subjected to a surface treatment such as a corona treatment or a glow treatment, if necessary, or may be provided with an undercoat layer such as vinylidene chloride or SBR. Further, the support may be dyed if necessary.

[0125]

The present invention will be described below in more detail with reference to examples, but the present invention is not limited to these examples.

Example 1 (Preparation of silver halide grains A) 22 g of phthalated gelatin and 30 mg of potassium bromide were dissolved in 700 ml of distilled water, and the temperature was adjusted to 40.
After adjusting the pH to 5.0 at C, 159 ml of an aqueous solution containing 18.6 g of silver nitrate and an aqueous solution containing potassium bromide and potassium iodide in a molar ratio of 92: 8 by a controlled double jet method while maintaining a pAg of 7.7. It was added over a minute. Then silver nitrate
476 ml of an aqueous solution containing 55.4 g and an aqueous solution containing 8 μmol / l of dipotassium hexachloridate and 1 mol / l of potassium bromide were added over 30 minutes by a controlled double jet method while maintaining the pAg at 7.7. Then pH
Then, the solution was subjected to coagulation and sedimentation for desalting treatment, and 0.1 g of phenoxyethanol was added to adjust to pH 5.9 and pAg 8.0. Silver iodide content core 8 mol%, average 2 mol%, grain size 0.0
7 μm, variation coefficient of projected area diameter 8%, (100) face ratio 86
% Cubic particles.

The temperature was adjusted to the obtained silver halide grains.
The temperature was raised to 60 ° C and 85 moles of sodium thiosulfate per mole of silver.
11 μmol of 2 μmol and 2,3,4,5,6-pentafluorophenyldiphenylphosphine selenide, 2 μmol of the following tellurium compound 1, 3.3 μmol of chloroauric acid and 230 μmol of thiocyanic acid were added, and 120 Aged for minutes.
Thereafter, the temperature was changed to 50 ° C., and the following sensitizing dye A was used in an amount of 5 × 10 ⁻⁴ mol per mol of silver halide, and the following sensitizing dye B was used.
^Was added with stirring at 2 × 10 ^-4 mol. Further, 3.5 mol% of potassium iodide was added to silver, the mixture was stirred for 30 minutes, and rapidly cooled to 30 ° C. to complete the preparation of silver halide grains A.

[0128]

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[0129]

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(Preparation of Organic Acid Silver Crystalline Dispersion) Behenic Acid
40 g, 7.3 g of stearic acid and 500 ml of water were stirred at a temperature of 90 ° C. for 15 minutes, 187 ml of 1N-NaOH was added over 15 minutes, 61 ml of a 1N aqueous nitric acid solution was added, and the temperature was lowered to 50 ° C. Next, 124 ml of a 1N silver nitrate aqueous solution was added over 2 minutes, and the mixture was stirred as it was for 30 minutes. Thereafter, the solid content was separated by suction filtration, and the solid content was washed with water until the conductivity of the filtrate reached 30 μS / cm. The solid thus obtained was treated as a wet cake without drying, and 12 g of polyvinyl alcohol and 150 ml of water were added to a wet cake equivalent to 34.8 g of dry solid, and mixed well to form a slurry. Prepare 840 g of zirconia beads having an average diameter of 0.5 mm, put them in a vessel together with the slurry, and use a disperser (1 / 4G sand grinder mill:
Dispersion for 5 hours using an IMEX Co., Ltd., and preparation of a microcrystal dispersion of silver salt of organic acid, which is needle-shaped particles having an average minor axis of 0.04 μm, an average major axis of 0.8 μm, and a projected area variation coefficient of 30% by observation with an electron microscope. Finished.

(Preparation of Solid Particle Dispersion of Reducing Agent) 4 g of hydroxypropylcellulose and 86 g of distilled water were added to 10 g of the following reducing agent, stirred well, and left as a slurry for 10 hours. After that, 168 g of zirconia beads having an average diameter of 0.5 mm were prepared, put in a vessel together with the slurry,
It was dispersed for 10 hours with the same dispersing machine used for preparing the organic acid silver microcrystal dispersion to obtain a solid fine particle dispersion. Particle size is 70
wt% was 1.0 μm or less.

[0132]

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(Preparation of Dispersion of Solid Fine Particles of Toning Agent) To 2.9 g and 2.1 g of the following toning agents 1 and 2 were added 2 g of hydroxypropylcellulose and 93 g of distilled water, and the mixture was stirred well and allowed to stand for 10 hours. Thereafter, 168 g of zirconia beads having an average diameter of 0.5 mm were prepared, put in a vessel together with the slurry, and dispersed for 10 hours with the same dispersing machine as used in the preparation of the reducing agent microcrystal dispersion, and the following toning agents 1 and 2 was obtained. As for the particle diameter, 70 wt% was 1.0 μm or less.

[0134]

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(Preparation of Coating Solution for Photosensitive Layer) The silver halide particles A were prepared by adding 10 mol% of silver halide / corresponding to the organic silver salt to the organic acid silver dispersion (corresponding to 1 mol of silver) prepared above. A polymer latex and materials were added to obtain an emulsion coating solution.

LACKSTAR 3307B (manufactured by Dainippon Ink and Chemicals, Incorporated; SBR latex) 430 g tribromomethylphenylsulfone 12 g reducing agent (reduced solid content as right) 98 g

Note that LACSTAR 3307B
Is a styrene-butadiene copolymer latex having an average particle size of the dispersed particles of about 0.1 to 0.15 μm.

(Preparation of Coating Solution for Surface Protective Layer) Toner gelatin (addition amount is as shown in Table 1),
0.5 g and 1.0 g respectively of the solid fine particle dispersion of No. 2
(Each of which is shown as the solid content of the color tone agent), 0.09 g of the following surfactant A, 0.08 g of the following surfactant B, 0.9 g of silica fine particles (average particle size 2.5 μm), 1,2-
(Bisvinylsulfonylacetamide) ethane 0.6
g of distilled water and 164 g of distilled water were added to obtain a coating solution for the surface protective layer.

[0139]

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(Preparation of Coloring Agent Dispersion) 35 g of ethyl acetate
2.5 g, 7.5 of the following compounds 1 and 2 respectively
g was added and stirred to dissolve. 50 g of a 10% by weight solution of polyvinyl alcohol previously dissolved in the solution was added, and 5
Stir with a homogenizer for minutes. Thereafter, the ethyl acetate was volatilized by removing the solvent and finally diluted with distilled water to prepare a color former dispersion.

[0141]

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(Preparation of Back Surface Coating Solution) Rack Star 3
To 60 g of 307B, 50 parts of the color former dispersion prepared above was used.
g, 20 g of the following compound, and 250 g of water were added to prepare a back surface coating solution.

[0143]

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(Preparation of Coating Solution for Back Surface Protective Layer) 0.09 g of the above-mentioned surfactant A and 0.09 g of the above-mentioned surfactant B were added to inert gelatin (added so that the coating amount is as shown in Table 1). 09g, silica fine particles (average particle size 12μm)
0.7 g, 0.6 g of 1,2- (bisvinylsulfonylacetamido) ethane and 164 g of distilled water were added to prepare a coating solution for the surface protective layer.

(Preparation of Undercoating Coating Liquid A) 300 ml of an aqueous dispersion of a styrene-butadiene copolymer (styrene / butadiene / acrylic acid = 68/29/3 (weight ratio), concentration: 30 wt%) in 680 ml of water, Activator B (1wt%) 2
0 ml was added to obtain an undercoating coating solution.

(Preparation of Undercoat Coating Solution B) 300 ml of an aqueous dispersion of a styrene-butadiene copolymer (styrene / butadiene / itaconic acid = 47/50/3 (weight ratio), concentration 30 wt%) in 680 ml of water, polystyrene fine particles ( Average particle size 2.5 μm) 0.1 g, surfactant B (1 wt%)
10 ml was added to obtain an undercoating coating solution.

(Preparation of Undercoat Coating Solution C) 10 g of inert gelatin was dissolved in 970 ml of water, and 20 ml of the above-mentioned surfactant B (1 wt%) was added thereto to prepare an undercoat coating solution.

(Preparation of undercoat support) The undercoat coating solution A was coated with a bar coater on one surface (photosensitive surface) of a 180 μm-thick biaxially stretched polyethylene terephthalate support tinted with a blue dye to a dry film thickness of 0%. It was applied to a thickness of 0.3 μm and dried at 180 ° C. for 5 minutes. Then, an undercoating coating solution B was applied to the back surface (back surface) using a bar coater so that the dry film thickness became 0.3 μm,
After drying at 5 ° C. for 5 minutes, an undercoating coating solution C was further applied thereon using a bar coater to a dry film thickness of 0.1 μm, and dried at 180 ° C. for 5 minutes to form an undercoating support. .

(Preparation of Coated Sample) The coating solution of the photosensitive layer prepared as described above was applied to the photosensitive surface of the support at a coating amount of silver of 1.
The coating solution for the surface protective layer was applied on the photosensitive layer so that the coating amount became 9 g / m ² and the coating amount of the binder was as shown in Table 1. The application was performed by applying two layers simultaneously and drying. After drying, apply the coating solution on the back side on the side opposite to the photosensitive layer (back side) to an optical density of 660 nm of 0.7.
A coating solution for the back surface protective layer was applied thereon so that the coating amount of the binder was as shown in Table 1. In this case, two layers were simultaneously coated and dried. Each sample was kept at 10 ° C for 1 minute after coating, and then kept at 50 ° C for 20 minutes.
Dried for minutes.

This sample was placed in an atmosphere of 25 ° C. and 60% RH for 1 hour.
After storage for 0 days, the following evaluation was performed.

(Evaluation of Equilibrium Moisture Content) The dispersion of Luckstar 3307B used for the photosensitive layer was applied on a glass plate,
For 1 hour to prepare a polymer model film having a thickness of 100 μm. Thereafter, the polymer model film was peeled off from the glass plate and left for 3 days at 25 ° C. and 60% RH, and the weight (W ₁ ) was measured. Then, the polymer model film was left in a vacuum for 3 days, quickly put into a weighing bottle whose weight was known, and the weight (W ₀ = W ₃ −W ₂ ) was measured. However, W ₃ is the weight of the model polymer film and a weighing bottle, W ₂ is the weight of the weighing bottle. Using W ₀ and W ₁ , the water content was determined by the following equation and found to be 0.6 wt%. Equilibrium water content = {(W ₁ −W ₀ ) / W ₀ } × 100 (wt%
)

(Evaluation of photographic performance) After exposing the photographic material at an angle of 30 degrees with respect to the normal line using a 647 nm Kr laser sensitometer (maximum output: 500 mW), the coated sample was developed at 120 ° C for 20 seconds.

The obtained images were evaluated using a densitometer. As a result, all samples showed Dmin. (Fog) and sensitivity (Dmi.
n. The reciprocal of the exposure ratio giving a density higher than 1.0), Dmax
Both were good.

(Evaluation of passability of heat developing machine) Length 10 cm ×
The coated sample was cut to a width of 5 cm, and the coated sample was passed through a heat developing machine (FIG. 2) having a stainless steel heat drum having a mirror-finished surface with a radius of 10 cm in the direction in which the photosensitive surface was hit, to thereby perform heat development. The drum temperature is 120 ° C. and the drum contact time is 20 seconds.
Each sample was subjected to development processing for 10 sheets at a time to evaluate the passability. Samples in which jamming occurred around the drum and samples in which the sample broke when it came out of the heat developing machine were determined to have poor passage properties. The results were expressed as the number of defective sheets out of 10 sheets. The heat development was performed at 25 ° C. in an atmosphere of 60% RH.

(Evaluation of curl) The sample was placed in an atmosphere heated to 120 ° C. by heating air at 25 ° C. and 60% RH, and after 5 minutes, the radius of curvature of the sample was measured. Using this value, the ANSI curl value was determined by the method described above. The curl value is + when the photosensitive surface is curled outward, and-when the photosensitive surface is curled inward.
Expressed by

Table 1 shows the results of the passability and curl of the heat developing machine.

[0157]

[Table 1]

Example 2 Example 1 was repeated except that the amounts of gelatin in the surface protective layer and the back surface protective layer were changed as shown in Table 2 and that thermal development was performed in such a direction that the back surface was in contact with the thermal drum during thermal development. Example 2 was performed in the same manner as described above. Table 2 shows the results of curl and passability.

[0159]

[Table 2]

Example 3 In the preparation of the silver halide grains prepared in Example 1, sensitizing dyes C and D were used instead of sensitizing dyes A and B, and 820 instead of 647 nm was used for evaluation of photographic performance.
Example 3 was evaluated in the same manner as in Example 1 except that a laser sensitometer having a diode of nm was used.
The same results as in Example 1 were obtained.

[0161]

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From the results of Examples 1, 2, and 3 above, the sample of the present invention has a good passage property through a heat developing machine, and the effect of the present invention is clear. It should be noted that those having an absolute value of ANSI curl at the time of development exceeding 5.0 were difficult to use. Also,
Those having a preferred range of 1.0 to 3.0 had an advantage that the transmissivity was good under any of the environmental humidity conditions of 25 ° C. 10% RH and 25 ° C. 90% RH.

[0163]

According to the present invention, the photographic properties are good and the passability with a heat developing machine is good.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an embodiment of an image exposure section and a heat development section of an image recording apparatus used for processing a photothermographic material according to the present invention.

FIG. 2 is a schematic diagram of a heat developing unit in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Laser light source 2 Halogen lamp 3 Rotating polygon mirror 4 Heat drum 5 Feed roller 6 Endless belt 7 Scanning lens 8 Photothermographic material 9 Mirror 10 Image exposure part 20 Thermal development part

Claims (6)

[Claims] 1. A photothermographic material wherein the absolute value of ANSI curl during thermal development is 0.5 or more. 2. A photosensitive silver halide, an organic silver salt and a reducing agent for the organic silver salt are provided on a support, and at least one layer of the photosensitive silver halide is provided on at least one surface of the support. A polymer latex is used as 50 wt% or more of the total binder of the photosensitive layer, and the photosensitive layer is formed by using a coating liquid in which 30 wt% or more of a solvent is water and the binder is dispersed. The photothermographic material according to claim 1, formed by drying after coating. 3. The polymer 2 of the polymer latex.
3. The photothermographic material according to claim 1, wherein the equilibrium water content at 5 ° C. and 60% RH is 2% by weight or less. 4. The photothermographic material according to claim 1, wherein the photothermographic material has a non-photosensitive layer in which at least 30% by weight of all binders is a hydrophilic polymer. 5. The photothermographic material according to claim 4, wherein said hydrophilic polymer is gelatin. 6. A method for thermally developing the photothermographic material according to claim 1, wherein the photothermographic material is conveyed on a heat drum by rotation of the heat drum, wherein the photothermographic material after separation from the heat drum is: A method for developing a photothermographic material, wherein the photothermographic material is transported so as to curl outward from a tangent at the peeling point of the photothermographic material of the heat drum.