JP2002287299A - Heat developable photosensitive material, image recording method and image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat developable photosensitive material which improves streak- or spot-like defects caused in processing with a heat developing apparatus used for a long period of time and to provide an image recording method and an image forming method using the heat developable photosensitive material. SOLUTION: The heat developable photosensitive material has a backing layer on one side of the base, an image forming layer containing photosensitive silver halide, an organic silver salt, a reducing agent for the organic silver salt and a binder on the other side and at least one surface protecting layer on the image forming layer. When 9.8 mN load is applied to the surface of the heat developable photosensitive material on the image forming layer side while the surface temperature is in the range of 10-60 deg.C, the rate of plastic deformation defined by the equation (rate (%) of plastic deformation)=(amount of plastic deformation)/[(amount of elastic deformation)+(amount of plastic deformation)×100 is <=50%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photothermographic material, an image recording method using the photothermographic material, and an image forming method. The present invention relates to a photothermographic material having improved scratches or spots, an image recording method using the photothermographic material, and an image forming method.

[0002]

2. Description of the Related Art Conventionally, in the fields of medical treatment and printing plate making, a waste liquid accompanying wet processing of an image forming material has been a problem in terms of workability. In recent years, a processing waste liquid has been considered from the viewpoint of environmental protection and space saving. There is a strong demand for weight loss. Therefore, a photothermographic material capable of forming an image only by applying heat has been put to practical use, and is rapidly spreading in the above-mentioned fields.

The photothermographic material itself has been proposed for a long time, for example, US Pat. No. 3,152,904,
No. 3,457,075, (D. Morgan
n) "Dry Silver Photographic Material (Dry Sil)
ver Photographic Material
l) ") or D.I. H. Crostavel (Kloster
Boer) "Thermally Processed Silver
er Systems) "(Imaging Pros and Materials (Imaging Pro)
cesses and Materials) Nebl
ette 8th edition, Sturge, V.E. Walworth, A .; Shepp (S
hepp), p. 279, 1989).

The heat development material is processed by an apparatus which forms an image by applying stable heat to the heat development material usually called a heat development processor. As described above, with the rapid spread in recent years, a large amount of this heat development processing apparatus has also been supplied to the market. May be worn away and coarse, and dust may be mixed in from the outside.In the process of heat development from cassette to exposure, development, and discharge, the photothermographic material will have finer protrusions and Local physical force is applied by Chile and the like. For this reason,
It has been newly found that the heat-developable photosensitive material does not cause the surface protective layer to be destroyed by the thermal development treatment, but that the surface protective layer is dented and causes streak-like or spot-like scratches. This phenomenon is a phenomenon that has not been observed in heat-developable materials that form an image by heat using a thermal head or the like. It was found that only significant occurrence occurred.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has as its object to provide a streak-like or spot-like flaw which is generated when a long-time heat development processing apparatus is used for processing. Another object of the present invention is to provide a photothermographic material improved from the above, an image recording method and an image forming method using the photothermographic material.

[0006]

The above object of the present invention has been attained by the following means.

[0007] 1. The support has a backing layer on one side, and a photosensitive silver halide, an organic silver salt,
In a photothermographic material having an image forming layer containing a reducing agent and a binder for an organic silver salt and at least one surface protective layer thereon, the surface temperature of the photothermographic material on the image forming layer side is preferably 10 or more. A photodevelopment method characterized in that, when a load of 9.8 mN is applied to the surface thereof at a temperature in the range of 60 ° C. to 60 ° C., the plastic deformation rate defined by the following formula (1) is 50% or less. material.

Formula (1) Plastic deformation rate (%) = Plastic deformation amount / (Elastic deformation amount + Plastic deformation amount) × 100 When the surface temperature on the image forming layer side is in the range from the heat development temperature to the heat development temperature −40 ° C., 1.96 mN
2. The photothermographic material according to item 1, wherein a plastic deformation rate defined by the formula (1) is 50% or less when a load is applied.

3. 3. The photothermographic material according to item 1 or 2, wherein the binder contained in the image forming layer has a glass transition temperature (Tg) of 70 ° C. or more and 105 ° C. or less.

[0010] 4. 4. The photothermographic material according to any one of items 1 to 3, wherein the surface protective layer on the image forming layer side contains colloidal inorganic fine particles.

5. (1) An antistatic layer containing a conductive metal oxide is provided on the backing layer.
5. The photothermographic material according to any one of items 1 to 4,

6. Any one of the above items 1 to 5, wherein any one of the layers on the image forming layer side contains a silver saving agent.
Item 6. The photothermographic material according to item 1.

7. 7. An image recording method, wherein the photothermographic material according to any one of the above items 1 to 6 is subjected to scanning exposure using a laser whose angle between the exposed surface and the laser beam does not become substantially perpendicular. Method.

8. 7. An image recording method, wherein the photothermographic material according to any one of 1 to 6 is subjected to scanning exposure using a vertical multi-laser having a non-uniform exposure wavelength.

9. 7. An image recording method, wherein the photothermographic material according to any one of the above items 1 to 6 is subjected to scanning exposure using two or more lasers.

10. 7. The photothermographic material according to any one of the above items 1 to 6, wherein
Thermal development is performed using a thermal development processing apparatus having a surface or a roller having at least one 0 μm protrusion per side length of the photothermographic material perpendicular to the transport direction of the photothermographic material. Image forming method of photothermographic material.

Hereinafter, the present invention will be described in detail. In the invention, the surface temperature of the photothermographic material is from 10 ° C to 60 ° C.
When a load of 9.8 mN is applied to the surface, the plastic deformation rate defined by the following equation (1) is 50% or less.

Equation (1) Plastic deformation rate (%) = Plastic deformation / (Elastic deformation + Plastic deformation) × 100 Equation (1) will be described. When a load is applied to the photothermographic material from the surface with needle-like protrusions, the material is deformed in accordance with the load. The deformation proceeds in three major steps.
The first stage is a reversible deformation process in which the photothermographic material is reversibly deformed like a spring in proportion to the elastic modulus of the photothermographic material. The second stage is a deformation that occurs after the first stage, and is a plastic deformation process in which the deformation does not return even if the load is released.
The third stage is a rupture process that eventually breaks as the deformation proceeds.

The term "plastic deformation rate" as used in the present invention is defined as a ratio of a plastic deformation which does not return to the original amount in the total deformation amount (elastic deformation amount + plastic deformation amount) when the deformation progresses to the second stage. It is. Further, immediately after the heat development, the heat-developable photosensitive material is softened by heat, including the support, and is easily plastically deformed. At a certain time, when a load of 1.96 mN is applied to the surface, a more preferable result can be obtained if the plastic deformation rate is 50% or less.

For the calculation of the plastic deformation rate, for example, a tester equipped with a small indenter (for example, a triangular pyramid indenter (plane angle 68 °)) such as a micro surface material evaluation system (MZT-3) manufactured by Akasi Corporation is used. This can be performed by measuring the amount of plastic deformation after applying a predetermined load and the total amount of deformation (elastic deformation + plastic deformation).

As a specific means for obtaining the above characteristics, it is preferable to use the invention according to claims 3 to 6. Hereinafter, components of the present invention will be described.

In the present invention, an organic silver salt as a silver ion supply source for forming a silver image is a silver salt of an organic acid or a hetero organic acid, particularly a long-chain (10 to 30 carbon atoms).
(15 to 25) Silver salts of aliphatic carboxylic acids and silver salts of nitrogen-containing heterocyclic compounds are preferred. Also preferred are the organic or inorganic complexes described in RD 17029 and 29963 in which the ligand has a value of 4.0 to 10.0 as the total stability constant for silver ions. Examples of these suitable silver salts include the following.

Silver salts of organic acids such as gallic acid, oxalic acid,
Silver salts such as behenic acid, stearic acid, arachidic acid, palmitic acid and lauric acid. Silver carboxyalkylthiourea salts, for example, silver salts such as 1- (3-carboxypropyl) thiourea, 1- (3-carboxypropyl) -3,3-dimethylthiourea, and aldehydes with hydroxy-substituted aromatic carboxylic acids Silver salts or complexes of polymer reaction products, for example, silver salts of reaction products of aldehydes (formaldehyde, acetaldehyde, butyraldehyde, etc.) and hydroxy-substituted acids (for example, salicylic acid, benzoic acid, 3,5-dihydroxybenzoic acid) Or complexes, silver salts or complexes of thiones, for example, 3- (2-carboxyethyl) -4-hydroxymethyl-4-thiazoline-2-thione, and 3-carboxymethyl-4-thiazoline-2
Silver salts or complexes such as -thione, imidazole, pyrazole, urazole, 1,2,4-thiazole and 1H-tetrazole, 3-amino-5-benzylthio-1,2,2;
Complexes or salts of nitrogen acids and silver selected from 4-triazole and benzotriazole, silver salts such as saccharin and 5-chlorosalicylaldoxime, and silver mercaptides.

Among these, particularly preferred silver salts include:
Long-chain (10 to 30 carbon atoms, preferably 15 to 25 carbon atoms) silver salts of aliphatic carboxylic acids such as silver behenate, silver arachidate and silver stearate can be mentioned.

In the present invention, it is preferable that two or more kinds of organic silver salts are mixed in order to enhance developability and to form a high-density, high-contrast silver image. It is preferable to prepare by mixing a silver ion solution.

The organic silver salt compound can be obtained by mixing a water-soluble silver compound and a compound which forms a complex with silver, and includes a forward mixing method, a reverse mixing method, a simultaneous mixing method, and a method described in JP-A-9-12764.
A controlled double jet method as described in No. 3 is preferably used. For example, an organic acid alkali metal salt soap (eg, sodium hydroxide, potassium hydroxide, etc.)
After preparing sodium behenate, sodium arachidate, etc., the above-mentioned soap and silver nitrate are mixed by a controlled double jet method to produce an organic silver salt crystal. At that time, silver halide grains may be mixed.

The organic silver salt according to the present invention may have various shapes, but tabular grains are preferred. In particular, tabular organic silver salt particles having an aspect ratio of 3 or more,
In addition, in order to reduce the shape anisotropy of the two substantially parallel surfaces (principal planes) having the largest area and to increase the filling rate in the photosensitive layer, the flat organic layer is measured from the principal plane direction. The average value of the needle ratio of the silver salt particles is 1.1 or more and 10.0 or more.
Particles that are less than are preferred. In addition, a more preferable needle ratio is 1.1 or more and less than 5.0.

In the present invention, the phrase "tabular organic silver salt grains having an aspect ratio of 3 or more" means that the tabular organic silver salt grains account for 50% or more of the total number of organic silver salt grains. Further, in the organic silver salt according to the present invention, the tabular organic silver salt particles having an aspect ratio of 3 or more preferably account for 60% or more of the total number of organic silver salt particles, and more preferably 70% or more (number). And it is particularly preferably at least 80% (number).

In the present invention, the tabular grains having an aspect ratio of 3 or more are those having a so-called aspect ratio (abbreviated as AR) of 3 or more expressed by the following formula.

AR = particle size (μm) / thickness (μm) The aspect ratio of the tabular organic silver salt particles according to the present invention is preferably from 3 to 20, more preferably from 3 to 10.
It is. The reason is that if the aspect ratio is too low, the organic silver salt particles are likely to be densest, and if the aspect ratio is too high, the organic silver salt particles are likely to overlap each other and disperse in a state of sticking. The above-mentioned range is preferable because light scattering or the like is likely to occur because the light-sensitive material tends to be transparent, and as a result, the transparency of the photosensitive material is reduced.

In order to measure the particle size of the organic silver salt particles described above, the dispersed organic silver salt is diluted and dispersed on a grid provided with a carbon support film, and is measured with a transmission electron microscope (for example, JEOL Ltd. Photographs are taken with a 2000FX type and a direct magnification of 5000 times, and the particle size is measured. When obtaining the average particle size, a negative image is captured as a digital image by a scanner, and 300 or more particle sizes (equivalent circle diameters) are measured using appropriate image processing software to calculate the average particle size.

The thickness of the organic silver salt particles described above is calculated by a method using a TEM (transmission electron microscope) as shown below.

First, the image forming layer applied on the support is adhered to an appropriate holder with an adhesive, and the thickness of the image forming layer is set to 0.1 to 0.1 mm using a diamond knife in a direction perpendicular to the surface of the support.
Prepare ultra-thin sections of 0.2 μm. The prepared ultrathin section is supported on a copper mesh, transferred onto a carbon film that has been hydrophilized by glow discharge, and cooled with liquid nitrogen to −130 ° C. or lower while being transmitted through a transmission electron microscope (hereinafter referred to as TEM).
Is used to observe a bright field image at a magnification of 5,000 to 40,000, and the image is quickly recorded on a film, an imaging plate, a CCD camera, or the like. At this time, as the visual field to be observed, it is preferable to appropriately select a portion where there is no break or looseness in the section.

It is preferable to use a carbon film supported by an organic film such as ultra-thin collodion, formbar or the like. More preferably, the carbon film is formed on a rock salt substrate and obtained by dissolving and removing the substrate. This is a carbon-only film obtained by removing the film by an organic solvent and ion etching. The accelerating voltage of TEM is 80 to 4
00 kV is preferable, and particularly preferably 80 to 200 kV.
V.

For details of the electron microscopy technique and the sample preparation technique, see "Japan Electron Microscopy Society Kanto Chapter / Medical and Biological Electron Microscopy" (Maruzen), "Japan Electron Microscopy Society Kanto Chapter / Electronics". Microscopic biological sample preparation method ”(Maruzen).

It is preferable that a TEM image recorded on an appropriate medium is decomposed into at least 1024 pixels × 1024 pixels, preferably 2048 pixels × 2048 pixels or more, and subjected to image processing by a computer. In order to perform image processing, it is preferable that an analog image recorded on a film is converted into a digital image by a scanner or the like, and shading correction, contrast / edge enhancement, and the like are performed as necessary. Thereafter, a histogram is prepared, and a portion corresponding to organic silver is extracted by a binarization process.

In order to determine the average thickness, the thickness of the extracted organic silver salt particles is manually measured with 300 or more suitable software, and the average value is determined.

The average value of the acicular ratio of the tabular organic silver salt particles can be determined by the following method. First, the photosensitive layer containing the tabular organic silver salt particles is swollen with an organic solvent capable of dissolving the photosensitive layer binder, separated from the support, and subjected to ultrasonic washing, centrifugation, and supernatant removal using the solvent. Repeat 5 times. The above steps are performed under safelight.

Subsequently, the mixture was diluted with MEK (methyl ethyl ketone) so that the organic silver solid content concentration was 0.01%.
After ultrasonic dispersion, the mixture is dropped on a polyethylene terephthalate film hydrophilized by glow discharge and dried.

The film on which the particles are mounted has a thickness of 3 ° at an angle of 30 ° with respect to the film surface by a vacuum evaporation apparatus.
After obliquely vapor-depositing Pt-C of nm with an electron beam, it is preferable to use it for observation.

For details of the electron microscope observation technique and the sample preparation technique, see “The Society of Electron Microscopy of Japan, Kanto Chapter / Medical and Biological Electron Microscopy” (Maruzen), “Japan Society of Electron Microscopy, Kanto Section / Electronics”. Microscopic biological sample preparation method ”(Maruzen).

The prepared sample was subjected to an acceleration voltage of 2 kV using a field emission scanning electron microscope (hereinafter referred to as FE-SEM).
The secondary electron image is observed at a magnification of 5,000 to 20,000 times at 4 to 4 kV, and the image is stored in an appropriate recording medium.

For the above processing, it is convenient to use a device capable of AD converting an image signal from the electron microscope main body and recording it directly as digital information on a memory, but the device is recorded on a Polaroid (registered trademark) film or the like. The converted analog image can also be used by converting it into a digital image using a scanner or the like and performing shading correction, contrast / edge enhancement, and the like as necessary.

As for an image recorded on an appropriate medium, it is preferable that one image is decomposed into at least 1024 pixels × 1024 pixels, preferably 2048 pixels × 2048 pixels or more, and image processing is performed by a computer.

As a procedure of the image processing described above, first, a histogram is prepared, and a portion corresponding to organic silver salt particles having an aspect ratio of 3 or more is extracted by binarization. The unavoidably agglomerated particles are cut by a suitable algorithm or manual operation to perform contour extraction. Thereafter, the maximum length (MX LNG) and the minimum width (WIDTH) of each particle are measured for at least 1000 particles, and the acicular ratio is determined for each particle by the following formula. Here, the maximum length of a particle refers to the maximum value when two points in the particle are connected by a straight line. The minimum width of a particle means a value when a distance between the parallel lines becomes a minimum value when two parallel lines circumscribing the particle are drawn.

Needle ratio = (MX LNG) ÷ (WIDTH) Thereafter, an average value of the needle ratios of all the measured particles is calculated. When the measurement is performed in the above procedure, it is preferable that the correction of the length per pixel (scale correction) and the correction of the two-dimensional distortion of the measurement system are sufficiently performed using a standard sample in advance. As a standard sample, Uniform Latex Particles (DULP) commercially available from Dow Chemical Co., USA is suitable, and polystyrene particles having a coefficient of variation of less than 10% with respect to a particle size of 0.1 to 0.3 μm are suitable. Preferably, specifically, the particle size is 0.2
Lots with 12 μm and standard deviation 0.0029 μm are available.

The details of the image processing technology can be referred to “Image Processing Applied Technology (Industrial Research Committee) edited by Hiroshi Tanaka”.
The image processing program or device is not particularly limited as long as the above operation can be performed, and an example is Luzex-III manufactured by Nireco.

The method for obtaining the organic silver salt particles having the above-mentioned shape is not particularly limited, but may be a mixed state when forming an organic acid alkali metal salt soap and / or a mixed state when adding silver nitrate to the soap. To keep it good,
It is effective to optimize the ratio of silver nitrate that reacts with the soap.

The tabular organic silver salt particles according to the present invention are preferably preliminarily dispersed together with a binder, a surfactant and the like, if necessary, and then dispersed and pulverized with a media disperser or a high-pressure homogenizer. For the preliminary dispersion, a general stirrer such as an anchor type or a propeller type, a high-speed rotary centrifugal radiation type stirrer (dissolver), and a high-speed rotary shear type stirrer (homomixer) can be used.

Examples of the media dispersing machine include a rolling mill such as a ball mill, a planetary ball mill and a vibrating ball mill, a bead mill as a medium stirring mill, an attritor, and the like.
Other basket mills and the like can be used,
Various types can be used as the high-pressure homogenizer, such as a type that collides with a wall, a plug, or the like, a type in which liquids are divided into a plurality of pieces and then the liquids collide at high speed, and a type that passes through a thin orifice.

As ceramics used for ceramic beads used at the time of media dispersion, for example, A
l ₂ O ₃ , BaTiO ₃ , SrTiO ₃ , MgO, ZrO,
_{BeO, Cr 2 O 3, SiO} 2, SiO 2 -Al 2 O 3, Cr
₂ O ₃ -MgO, MgO-CaO, MgO-C, MgO-
Al ₂ O ₃ (spinel), SiC, TiO ₂ , K ₂ O, Na
₂ O, BaO, PbO, B ₂ O ₃ , SrTiO ₃ (strontium titanate), BeAl ₂ O ₄ , Y ₃ Al ₅ O ₁₂ , Zr
O ₂ -Y ₂ O ₃ (cubic zirconia), 3BeO-Al ₂ O
₃ -6SiO ₂ (Synthesis emerald), C _{(diamond), Si 2 O-nH 2} O, ticker silicon, yttrium stabilized zirconia, zirconia toughened alumina, and the like are preferable. Yttrium-stabilized zirconia and zirconia reinforced alumina (these zirconia-containing ceramics are hereinafter abbreviated as zirconia) are particularly preferably used because, for example, the generation of impurities due to friction with beads and a disperser during dispersion is small.

In the apparatus used for dispersing the tabular organic silver salt particles according to the present invention, ceramics such as zirconia, alumina, silicon nitride, boron nitride, etc. It is preferable to use diamond, and it is particularly preferable to use zirconia.

In carrying out the above dispersion, the binder concentration is preferably 0.1 to 10% of the mass of the organic silver.
It is preferable that the liquid temperature does not exceed 45 ° C. from the preliminary dispersion to the main dispersion. Preferred operating conditions for the dispersion include, for example, when a high-pressure homogenizer is used as the dispersing means, 29.42 MPa to 98.06 MPa, and the number of times of operation is preferably 2 or more.
Also, when using a media dispersing machine as a dispersing means,
Preferred conditions include a peripheral speed of 6 m / sec to 13 m / sec.

In a preferred embodiment of the photothermographic material according to the present invention, the ratio of organic silver salt particles exhibiting a projected area of less than 0.025 μm ² when a cross section perpendicular to the support surface of the material is observed with an electron microscope. Represents 70% or more of the total projected area of the organic silver salt particles, and the proportion of particles having a projected area of 0.2 μm ² or more is 10% of the total projected area of the organic silver salt particles.
% Or less, and a photosensitive emulsion containing photosensitive silver halide is coated thereon. In such a case, it is possible to obtain a state in which the organic silver salt particles are less aggregated and uniformly distributed in the photosensitive emulsion.

The conditions for preparing a photosensitive emulsion having such characteristics are not particularly limited, but include a mixed state when forming an organic acid alkali metal salt soap and / or a mixed state when adding silver nitrate to the soap. To keep the good, and to optimize the ratio of silver nitrate reacting with soap, to disperse and pulverize by dispersing with a media disperser or a high-pressure homogenizer, at which time the binder concentration is 0.1 to 10 of the organic silver mass In addition to the fact that the temperature from drying to the end of the main dispersion does not exceed 45 ° C.,
At the time of liquid preparation, stirring is preferably performed using a dissolver at a peripheral speed of 2.0 m / sec or more.

The projection area of the organic silver particles having the specific projection area value as described above and the ratio of the total projection area can be determined in the same manner as described in the section for determining the average thickness of the tabular grains described above. A portion corresponding to organic silver is extracted by a method using a TEM (transmission electron microscope).

At this time, the aggregated organic silver is treated as one particle, and the area (AREA) of each particle is determined. Similarly, at least 1,000, preferably 2,000
The area is determined for 0 particles, and for each,
A: 0.025 .mu.m less than ^2, B: 0.025μm ² or more 0.2 [mu] m less than ^2, C: classified into 0.2 [mu] m ² or more of the three groups. In the light-sensitive material of the present invention, the total area of the particles belonging to Group A is 70% or more of the measured area of all the particles;
Further, it is preferable that the total area of the particles belonging to the group C satisfies 10% or less of the area of all the measured particles.

When the measurement is performed in the above procedure, it is preferable that the correction of the length per pixel (scale correction) and the correction of the two-dimensional distortion of the measurement system be sufficiently performed using a standard sample in advance. As a standard sample, Uniform Latex Particles (DULP) commercially available from Dow Chemical Co., USA is suitable, and polystyrene particles having a coefficient of variation of less than 10% with respect to a particle size of 0.1 to 0.3 μm are suitable. Preferably, specifically, the particle size is 0.2
Lots with 12 μm and standard deviation 0.0029 μm are available.

The details of the image processing technique can be referred to “Image processing application technique (Industrial Research Committee) edited by Hiroshi Tanaka” as described above. The image processing program or apparatus is not particularly limited as long as the above-mentioned operations can be performed. Although not performed, Luzex-III manufactured by Nireco is also mentioned as an example.

The organic silver salt particles according to the present invention are preferably monodisperse particles.
The content is 30%, and an image having a high density can be obtained by using monodispersed particles in this range. Here, the monodispersity is defined by the following equation.

Monodispersity = (standard deviation of particle size) / (average value of particle size) × 100 The average particle size (equivalent circle diameter) of the above-mentioned organic silver salt is 0.01.
To 0.2 μm, more preferably 0.02 to
0.15 μm. The average particle diameter (equivalent circle diameter) indicates the diameter of a circle having the same area as an individual particle image observed with an electron microscope.

In the present invention, in order to prevent devitrification of the light-sensitive material, the total amount of silver halide and organic silver salt is preferably from 0.5 g to 2.2 g per m ² in terms of silver. . When used as a medical image by setting this range, a preferable image is obtained.

The photosensitive silver halide grains in the present invention will be described. Incidentally, the photosensitive silver halide grains in the present invention can inherently absorb light as an inherent property of silver halide crystals, or artificially emit visible light or infrared light by a physicochemical method. Physicochemical changes may occur in the silver halide crystal and / or on the crystal surface when light can be absorbed and light in any region within the light wavelength range from the ultraviolet light region to the infrared light region is absorbed. Silver halide crystal grains that have been processed and manufactured as described above.

The silver halide grains used in the present invention may be P.I. Chimie et P by Glafkides
hysique Photographique (Pa
ulMontel, 1967); F. Duf
fin Photographic Emulsio
n Chemistry (The Focal Pre
ss, 1966); L. Zelikman e
Making and Coating P by tal
photographic Emulsion (The
Focal Press, 1964) can be used to prepare a silver halide grain emulsion. That is, any of an acidic method, a neutral method, an ammonia method, and the like may be used, and a method of reacting a soluble silver salt with a soluble halide may be any of a one-sided mixing method, a simultaneous mixing method, a combination thereof, and the like. Of these methods, the so-called controlled double jet method of preparing silver halide grains while controlling the formation conditions is preferable among the above methods. The halogen composition is not particularly limited, and may be any of silver chloride, silver chlorobromide, silver chloroiodobromide, silver bromide, silver iodobromide, and silver iodide.

Grain formation is usually divided into two stages of silver halide seed grain (nucleus) generation and grain growth. These methods may be carried out continuously at a time, or nucleus (seed grain) formation and grain growth may be carried out. A method in which separation is performed may be used. The controlled double jet method for forming particles by controlling the pAg, pH and the like, which are the particle forming conditions, is preferred because the shape and size of the particles can be controlled. For example, when performing a method in which nucleation and grain growth are performed separately, first, a silver salt aqueous solution and a halide aqueous solution are uniformly and rapidly mixed in a gelatin aqueous solution to generate nuclei (seed particles) (nucleation step). ,
Silver halide grains are prepared by a grain growth step of growing grains while supplying a silver salt aqueous solution and a halide aqueous solution under controlled pAg, pH, and the like. After particle formation
A desired silver halide emulsion can be obtained by removing unnecessary salts and the like in the desalting step by a known desalting method such as a noodle method, flocculation method, ultrafiltration method, and electrodialysis method.

The silver halide of the present invention preferably has a small average grain size in order to suppress white turbidity after image formation and obtain good image quality, and the average grain size is preferably 0.2 μm or less, more preferably 0.01 μm to 0.1
7 μm, particularly preferably 0.02 μm to 0.14 μm.
The term "grain size" as used herein refers to the length of a ridge of a 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 present invention, the silver halide grains are preferably monodispersed. The term “monodisperse” as used herein means that the coefficient of variation of the particle size obtained by
It means 0% or less. It is preferably at most 20%, more preferably at most 15%.

Coefficient of variation of grain size% = Standard deviation of grain size / Average grain size × 100 The shape of silver halide grains is cubic, octahedral, 14
Examples thereof include a tabular grain, a tabular grain, a spherical grain, a rod-like grain, and a potato-like grain. Among them, cubic, octahedral, tetradecahedral, and tabular silver halide grains are particularly preferable.

When tabular silver halide grains are used, the average aspect ratio is preferably from 1.5 to 100, more preferably from 2 to 50. These are U.S. Patent Nos. 5,264,337 and 5,314,798,
No. 5,320,958 and the like, and desired tabular grains can be easily obtained. Further, grains having rounded corners of silver halide grains can also be preferably used.

The crystal habit on the outer surface of the silver halide grains is not particularly limited, but a sensitizing dye having crystal habit (plane) selectivity is used in the adsorption reaction of the sensitizing dye on the surface of the silver halide grains. In this case, it is preferable to use silver halide grains having a relatively high proportion of crystal habit adapted to the selectivity. For example, when a sensitizing dye that selectively adsorbs to a crystal plane having a Miller index of [100] is used, the ratio of the [100] plane to the outer surface of the silver halide grains is preferably high, and this ratio is 50%. %, More preferably 70% or more, particularly preferably 80% or more. The ratio of the Miller index [100] plane is determined by the T.V. method using the dependence of the adsorption of the sensitizing dye on the [111] plane and the [100] plane. Tani, J .; Imaging Sci. ,
29, 165 (1985).

The silver halide grains used in the present invention are:
It is preferable to use a low molecular weight gelatin having an average molecular weight of 50,000 or less when forming the grains, but it is particularly preferable to use the same when forming nuclei of silver halide grains.

In the present invention, the low molecular weight gelatin has an average molecular weight of 50,000 or less, and preferably has a molecular weight of 2,000 to 4,000.
0000, more preferably 5,000 to 25,000. The average molecular weight of gelatin can be measured by gel filtration chromatography.

The low-molecular-weight gelatin may be enzymatically decomposed by adding a gelatin-decomposing enzyme to a commonly used aqueous gelatin solution having an average molecular weight of about 100,000, or may be hydrolyzed by adding an acid or an alkali and heating, or under atmospheric pressure or pressure. , Or by irradiation with ultrasonic waves, or by using these methods in combination.

The concentration of the dispersion medium at the time of nucleation is preferably 5% by mass or less, and it is effective to carry out the concentration at a low concentration of 0.05 to 3.0% by mass.

The silver halide grains used in the present invention are:
It is preferable to use a compound represented by the following general formula at the time of forming the particles.

The general formula YO (CH ₂ CH ₂ O) _m (CH (CH ₃ ) CH ₂ O) _p (C
H ₂ CH ₂ O) _n Y wherein Y is a hydrogen atom, —SO ₃ M, or —CO—B—C
OOM, M represents a hydrogen atom, an alkali metal atom, an ammonium group or an ammonium group substituted with an alkyl group having 5 or less carbon atoms, and B represents a chain or cyclic group forming an organic dibasic acid. Represent. m and n each represent 0 to 50, and p represents 1 to 100.

The polyethylene oxide compound represented by the above general formula is used for producing a silver halide photographic light-sensitive material, a step of producing an aqueous gelatin solution, and a step of adding a water-soluble halide and a water-soluble silver salt to the gelatin solution. It has been preferably used as an antifoaming agent against remarkable foaming when the emulsion raw material is stirred or moved, such as a step of coating the emulsion on a support. No. 44-9497. The polyethylene oxide compound represented by the above general formula also functions as an antifoaming agent at the time of nucleation.

The compound represented by the above general formula is preferably used in an amount of 1% by mass or less based on silver, more preferably 0.01 to 0.1% by mass.

The polyethylene oxide compound represented by the above general formula may be present at the time of nucleation, and is preferably added in advance to the dispersion medium before nucleation, but may be added during nucleation. Alternatively, it may be used by adding it to an aqueous silver salt solution or an aqueous halide solution used for nucleation. Preferably, it is used by adding 0.01 to 2.0% by mass to an aqueous halide solution or both aqueous solutions. Also, the compounds of the present invention are preferably present for at least 50% of the time of the nucleation step, more preferably for at least 70% of the time. The compound represented by the above general formula may be added as a powder or may be added after being dissolved in a solvent such as methanol.

The temperature at the time of nucleation is 5 to 60 ° C., preferably 15 to 50 ° C. Even if the temperature is constant, the temperature rise pattern (for example, the temperature at the start of nucleation is 25 ° C.
During the nucleation, the temperature was gradually increased.
It is preferable that the temperature is controlled within the above-mentioned temperature range even in the case of the case of (° C.) or the reverse pattern.

The concentration of the silver salt aqueous solution and the halide aqueous solution used for nucleation is preferably 3.5 N or less, more preferably 0.03 N or less.
It is preferably used in a low concentration range of 1 to 2.5 normal.
The rate of addition of silver ion during nucleation is preferably reaction 1l per 1.5 × 10 ^-3 mol / min to 3.0 × 10 ^-1 mol / min, more preferably 3.0 × 10 ^-3 mol / Min ~ 8.
It is 0 × 10 ^-2 mol / min.

The pH at the time of nucleation can be set in the range of 1.7 to 10, but the pH at the alkali side is preferably pH 2 to 6 in order to broaden the particle size distribution of nuclei to be formed. Also, pBr at the time of nucleation is about 0.05 to 3.0, preferably 1.
0 to 2.5, further 1.5 to 2.0.

The silver halide grains according to the present invention may be added to the image forming layer by any method. In this case, the silver halide grains are arranged so as to be close to a reducible silver source (organic silver salt). Is preferred.

The silver halide used in the present invention is prepared in advance and added to a solution for preparing organic silver salt grains. It is also preferable from the viewpoint of production control because it can be treated as a silver salt. However, as described in British Patent No. 1,447,454, a halogen component such as a halide ion is used to form an organic silver salt when preparing organic silver salt particles. By coexisting with the components and injecting silver ions into them, they can be formed almost simultaneously with the generation of the organic silver salt particles.

It is also possible to prepare a silver halide grain by subjecting an organic silver salt to a halogen-containing compound and converting the organic silver salt. That is, a silver halide-forming component is applied to a solution or dispersion of an organic silver salt prepared in advance or a sheet material containing the organic silver salt to convert a part of the organic silver salt into photosensitive silver halide. Can also.

The silver halide forming component includes inorganic halogen compounds, onium halides, halogenated hydrocarbons, N-halogen compounds, and other halogen-containing compounds. Specific examples thereof are described in US Pat. 0
No. 39, No. 3,457,075, No. 4,003
No. 749, British Patent Nos. 1,498,956 and JP-A-53-27027 and JP-A-53-25420, metal halides and inorganic halides such as ammonium halides, for example, trimethyl. Onium halides such as phenylammonium bromide, cetylethyldimethylammonium bromide, trimethylbenzylammonium bromide, for example, iodoform, bromoform, carbon tetrachloride, 2-bromo-2
-Halogenated hydrocarbons such as -methylpropane, N-bromosuccinimide, N-bromophthalimide, N-halogen compounds such as N-bromoacetamide, and others, for example,
Triphenylmethyl chloride, triphenylmethyl bromide, 2
-Bromoacetic acid, 2-bromoethanol, dichlorobenzophenone and the like. In this manner, the silver halide can also be prepared by converting a part or all of the silver in the organic acid silver salt to silver halide by reacting the organic acid silver with the halide ion. Further, silver halide grains produced by converting a part of these organic silver salts to separately prepared silver halide may be used in combination.

The silver halide grains were prepared separately from silver halide grains prepared separately and silver halide grains obtained by conversion of an organic silver salt with respect to 1 mole of the organic silver salt.
It is preferred to use 1 mol to 0.7 mol, preferably 0.03 mol to 0.5 mol.

The silver halide used in the present invention preferably contains ions of transition metals belonging to groups 6 to 11 of the periodic table. As the above metal, W,
Fe, Co, Ni, Cu, Ru, Rh, Pd, Re, O
s, Ir, Pt, and Au are preferred. These may be used alone or in combination of two or more of the same or different metal complexes.
These metal ions may be directly introduced into silver halide as a metal salt, but can be introduced into silver halide in the form of a metal complex or complex ion. The preferred content is in the range of 1 × 10 ⁻⁹ mol to 1 × 10 ⁻² mol per mol of silver, and more preferably in the range of 1 × 10 ⁻⁸ to 1 × 10 ⁻⁴ . In the present invention, the transition metal complex or complex ion is preferably represented by the following general formula.

In the general formula [ML ₆ ] _m , M represents a transition metal selected from elements of Groups 6 to 11 of the periodic table, L represents a ligand, and m represents 0,-, 2-, 3-.
Or 4-. Specific examples of the ligand represented by L include halogen ion (fluoride ion, chloride ion, bromide ion, iodine ion), cyanide, cyanate, thiocyanate, selenocyanate, tellurocyanate, azide and aquo. Ligand, nitrosyl, thionitrosyl and the like, preferably aquo, nitrosyl and thionitrosyl. If an aquo ligand is present, it preferably occupies one or two of the ligands. L may be the same or different.

The compound which provides these metal ions or complex ions is preferably added during silver halide grain formation and incorporated into the silver halide grains. Preparation of silver halide grains, that is, nucleation and growth , Physical aging,
Although it may be added at any stage before and after chemical sensitization, it is particularly preferable to add at the stage of nucleation, growth, and physical ripening,
Further, it is preferably added at the stage of nucleation and growth, most preferably at the stage of nucleation. In the addition, the compound may be added in several divided portions, may be added uniformly in the silver halide grains, or may be added uniformly to the silver halide grains, as described in JP-A-63-29603, JP-A-2-306236, and JP-A-2-306236.
167545, 4-76534, 6-110
As described in JP-A-146-146, JP-A-5-273683 and the like, the particles can be contained in the particles with distribution.

These metal compounds can be added by dissolving them in water or a suitable organic solvent (eg, alcohols, ethers, glycols, ketones, esters, amides). A method of adding an aqueous solution of a powder or an aqueous solution in which a metal compound and NaCl and KCl are dissolved together to a water-soluble silver salt solution or a water-soluble halide solution during particle formation, or a method in which a silver salt aqueous solution and a halide aqueous solution are used. When they are mixed simultaneously, they are added as a third aqueous solution to prepare silver halide grains by a three-liquid simultaneous mixing method, a method in which a required amount of an aqueous solution of a metal compound is charged into a reaction vessel during grain formation, or There is a method in which another silver halide grain doped with a metal ion or a complex ion in advance at the time of preparing silver halide is added and dissolved. In particular, a method in which an aqueous solution of a powder of a metal compound or an aqueous solution in which a metal compound and NaCl and KCl are dissolved together is added to an aqueous halide solution is preferable. When adding to the particle surface, a required amount of an aqueous solution of a metal compound can be charged into the reaction vessel immediately after the formation of the particles, during or at the end of physical ripening, or at the time of chemical ripening.

The photosensitive silver halide grains separately prepared can be desalted by a known desalting method such as a noodle method, flocculation method, ultrafiltration method, and electrodialysis method.
The photothermographic material can be used without desalting.

The silver halide grains used in the present invention can be subjected to chemical sensitization. For example, Japanese Patent Application 2000-
According to the method disclosed in the specification of Japanese Patent No. 57004 and Japanese Patent Application No. 2000-61942, a chemical sensitization center is prepared using a compound having a chalcogen atom such as sulfur or a noble metal compound which releases a noble metal ion such as a gold ion. A chemical sensitizing nucleus).

In the present invention, it is preferable that the compound is chemically sensitized by a compound containing a chalcogen atom shown below.

The compound containing a chalcogen atom useful as an organic sensitizer is preferably a compound having a group capable of adsorbing to silver halide and an unstable chalcogen atom site.

These organic sensitizers are disclosed in
Organic sensitizers having various structures disclosed in the specification of JP-A-150046, JP-A-4-109240, JP-A-11-218874 and the like can be used. Among them, a chalcogen atom is a carbon atom. Alternatively, it is preferably at least one kind of compound having a structure linked to a phosphorus atom by a double bond.

The amount of the compound containing a chalcogen atom used as an organic sensitizer varies depending on the chalcogen compound used, silver halide grains, the reaction environment for chemical sensitization, and the like. ^{-10 -8} to 10
^-2 mol is preferable, and more preferably 10 ^-7 to 10 ^-3 mol is used. The chemical sensitizing environment in the present invention is not particularly limited, but in the presence of a compound capable of eliminating or reducing the size of chalcogenide or silver nuclei on the photosensitive silver halide grains, and particularly, in the presence of silver nuclei. Chalcogen sensitization is preferably performed using an organic sensitizer containing a chalcogen atom in the presence of an oxidizing agent capable of oxidizing the chalcogen atom. As the sensitization condition, the pAg is preferably from 6 to 11, more preferably from 7 to 11. -10, and the pH is preferably 4-10, more preferably 5-8, and the sensitization is preferably performed at a temperature of 30 ° C. or lower.

Therefore, in the photothermographic material of the present invention, the photosensitive silver halide uses an organic sensitizer containing a chalcogen atom in the presence of an oxidizing agent capable of oxidizing silver nuclei on the grains. It is preferable to use a photosensitive emulsion which has been subjected to chemical sensitization at a temperature of 30 ° C. or lower, mixed with an organic silver salt, dispersed, dehydrated and dried.

The chemical sensitization using these organic sensitizers is preferably carried out in the presence of a spectral sensitizing dye or a heteroatom-containing compound having adsorptivity to silver halide grains. By performing chemical sensitization in the presence of a compound having adsorptivity to silver halide, dispersion of the chemical sensitization center nucleus can be prevented, and high sensitivity and low fog can be achieved. The spectral sensitizing dye used in the present invention will be described later, and the heteroatom-containing compound having adsorptivity to silver halide is preferably a nitrogen-containing heterocyclic compound described in JP-A-3-24537. can give. In the nitrogen-containing heterocyclic compound used in the present invention, the heterocyclic ring is a pyrazole ring, a pyrimidine ring, a 1,2,4-triazole ring, a 1,2,3-triazole ring, a 1,3,4-
Thiadiazole ring, 1,2,3-thiadiazole ring,
1,2,4-thiadiazole ring, 1,2,5-thiadiazole ring, 1,2,3,4-tetrazole ring, pyridazine ring, 1,2,3-triazine ring, and these rings are 2-3
Individually bonded rings such as a triazolotriazole ring, a diazaindene ring, a triazaindene ring, and a pentaazaindene ring can be exemplified. A condensed heterocyclic ring of a monocyclic heterocyclic ring and an aromatic ring, for example, a phthalazine ring, a benzimidazole ring, an indazole ring, a benzthiazole ring and the like can also be applied.

Preferred among these are azaindene rings and azaindene compounds having a hydroxyl group as a substituent, for example, hydroxytriazaindene,
Hydroxytetraazaindene, hydroxypentaazaindene compounds and the like are more preferred.

The heterocyclic ring may have a substituent other than a hydroxyl group. Examples of the substituent include an alkyl group, a substituted alkyl group, an alkylthio group, an amino group, a hydroxyamino group, an alkylamino group, a dialkylamino group, an arylamino group, a carboxyl group, an alkoxycarbonyl group, a halogen atom, and a cyano group. You may.

The amount of the heterocyclic compound to be added varies over a wide range depending on the size, composition, and other conditions of the silver halide grains, but the approximate amount is 10 to 10 mol per mol of silver halide. The range is from ^-6 mol to 1 mol, preferably from 10 ^-4 mol to 10 ^-1 mol.

As described above, the silver halide grains according to the present invention can be sensitized with a noble metal using a compound that releases a noble metal ion such as a gold ion. For example,
Chloroaurate or an organic gold compound can be used as the gold sensitizer.

In addition to the above-described sensitization methods, reduction sensitization methods and the like can also be used. Examples of reduction-sensitized shell-like compounds include ascorbic acid, thiourea dioxide, stannous chloride, and hydrazine derivatives. , Borane compounds, silane compounds, polyamine compounds and the like can be used. Further, when the pH of the emulsion is 7
Reduction sensitization can be achieved by ripening while maintaining the above or pAg at 8.3 or less.

The silver halide to be subjected to chemical sensitization according to the present invention may be formed in the presence of an organic silver salt, may be formed in the absence of an organic silver salt,
Both may be mixed.

The photosensitive silver halide grains used in the present invention are preferably subjected to spectral sensitization by adsorbing a spectral sensitizing dye. As the spectral 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. For example, JP-A-63
-159841, 60-14335, 63-
No. 231437, No. 63-259651, No. 63-3
04242, 63-15245, U.S. Pat.
The sensitizing dyes described in Nos. 639,414, 4,740,455, 4,741,966, 4,751,175, and 4,835,096 can be used. . Useful sensitizing dyes for use in the present invention are, for example, RD
17643 IV-A (p. 23, December 1978) and 18431X (p. 437, August 1978) are described in the references or cited. In particular, it is preferable to use a sensitizing dye having a spectral sensitivity suitable for the spectral characteristics of various laser imagers and scanner light sources. For example, JP-A Nos. 9-34078, 9-54409, and 9
The compounds described in -80679 are preferably used.

Useful cyanine dyes are, for example, cyanine dyes having a basic nucleus such as a thiazoline nucleus, an oxazoline nucleus, a pyrroline nucleus, a pyridine nucleus, an oxazole nucleus, a thiazole nucleus, a selenazole nucleus and an imidazole nucleus. 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.

In the present invention, it is particularly preferable to use a sensitizing dye having a spectral sensitivity in the infrared. In the present invention, examples of the infrared spectral sensitizing dye preferably used include, for example, US Pat. Nos. 4,536,473 and 4,51.
And infrared spectral sensitizing dyes disclosed in US Pat. Nos. 5,888 and 4,959,294.

As the infrared spectral sensitizing dye used in the present invention, a long-chain polymethine dye characterized by having a sulfinyl group substituted on the benzene ring of a benzazole ring is particularly preferable.

The above-mentioned infrared sensitizing dye is described, for example, by FM Hammer, The Chemistry of H
eterocyclic Compounds No. 18
Volume, The Cyanine Dyes and Re
rated Compounds (A. Weissbe
rger ed. Published by Interscience, Ne
w York 1964).

These infrared sensitizing dyes may be added at any time after the preparation of the silver halide. For example, the infrared sensitizing dye may be added to a solvent, or may be added to a silver halide grain in a so-called solid dispersion state dispersed in fine particles. It can be added to a photosensitive emulsion containing silver halide grains / organic silver salt grains. Also, like the heteroatom-containing compound having an adsorptive property to the silver halide grains, the chemical sensitization can be performed after adding and adsorbing the silver halide grains prior to the chemical sensitization. The chemical sensitivity nucleus can be prevented from dispersing by high sensitivity,
Low fog can be achieved.

In the present invention, the above-mentioned spectral sensitizing dyes may be used alone or in combination.
Combinations of sensitizing dyes are often used, especially for supersensitization.

The emulsion containing silver halide grains or organic silver salt grains used in the photothermographic material of the present invention, together with a sensitizing dye, a dye having no spectral sensitizing effect by itself or a visible light is substantially used. The emulsion may contain a substance which does not absorb light into the emulsion and exhibits a supersensitizing effect, whereby the silver halide grains may be supersensitized.

Useful sensitizing dyes, combinations of dyes exhibiting supersensitization and substances exhibiting supersensitization are described in RD17643 (19).
(Issued December 1978) Page 23, IV, J, or JP-B Nos. 9-25500 and 43-4933;
19032, 59-192242, JP-A-5-3
No. 41432, etc., in the present invention, a heteroaromatic mercapto compound or a mercapto derivative compound represented by the following general formula is preferred as a supersensitizer.

General Formula Ar-SM In the formula, M is a hydrogen atom or an alkali metal atom;
r is a heteroaromatic or fused aromatic ring having one or more nitrogen, sulfur, oxygen, selenium, or tellurium atoms. Preferred heteroaromatic rings or fused aromatic rings are benzimidazole, naphthimidazole, benzthiazole, naphthothiazole, benzoxazole, naphthoxazole, benzselenazole, benztellurazole, imidazole, oxazole, pyrazole, triazole, triazine, pyrimidine, pyridazine, Examples include pyrazine, pyridine, purine, quinoline, and quinazoline. However, other heteroaromatic rings are also included.

It should be noted that the present invention also includes a mercapto derivative compound which substantially produces the above-mentioned mercapto compound when contained in a dispersion of an organic acid silver salt or a silver halide grain emulsion. Particularly, a mercapto derivative compound represented by the following general formula is mentioned as a preferable example.

Ar in the general formula Ar-SS-Ar has the same meaning as in the mercapto compound represented by the general formula.

The above-mentioned heteroaromatic ring or condensed aromatic ring includes, for example, a halogen atom (eg, Cl, Br, I), a hydroxyl group, an amino group, a carboxyl group, an alkyl group (eg, one or more carbon atoms, preferably Are those having 1 to 4 carbon atoms) and alkoxy groups (for example,
One or more carbon atoms, preferably those having 1 to 4 carbon atoms).

In the present invention, a compound represented by the following general formula (1) and a macrocyclic compound disclosed in Japanese Patent Application No. 12-070296 may be used in addition to the supersensitizer described above. It can be used as a supersensitizer.

[0120]

Embedded image

In the formula, H ₃₁ Ar represents an aromatic hydrocarbon group or an aromatic heterocyclic group, T ₃₁ represents a divalent linking group or a linking group comprising an aliphatic hydrocarbon group, and J ₃₁ represents an oxygen atom ,
Represents a divalent linking group or linking group containing at least one sulfur atom or nitrogen atom. Ra, Rb, Rc and Rd are each:
Represents a hydrogen atom, an acyl group, an aliphatic hydrocarbon group, an aryl group or a heterocyclic group, or Ra and Rb, Rc and Rd,
A bond between Ra and Rc or between Rb and Rd can form a nitrogen-containing heterocyclic group. M ₃₁ represents an ion necessary to compensate for intramolecular charge, k31 represents the number of ion required to offset the molecular charge.

In the general formula (1), the divalent linking group consisting of the aliphatic hydrocarbon group represented by T ₃₁ is a straight-chain,
A branched or cyclic alkylene group (preferably having 1 to
20, more preferably 1 to 16, even more preferably 1 to 1
2), an alkenyl group (preferably having 2 to 20, more preferably 2 to 16, more preferably 2 to 12), an alkynyl group (preferably having 2 to 20, more preferably 2 to 16, more preferably 2 to 12), which may have a substituent. For example, as the aliphatic hydrocarbon group,
A linear, branched or cyclic alkyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16, more preferably 1 to 16 carbon atoms)
-12), alkenyl group (preferably having 2 to 20 carbon atoms,
More preferably 2 to 16, even more preferably 2 to 12),
An alkynyl group (preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, and still more preferably 2 to 12 carbon atoms). As the aryl group, a monocyclic or condensed aryl group having 6 to 20 carbon atoms (for example, Phenyl, naphthyl and the like,
Preferably phenyl), and the heterocyclic group is preferably 3 to
A 10-membered saturated or unsaturated heterocyclic group (for example, 2-thiazolyl, 1-piperazinyl, 2-pyridyl, 3-pyridyl, 2-furyl, 2-thienyl, 2-benzimidazolyl, carbazolyl, etc.), The hetero ring in these groups may be a single ring or may form a condensed ring with another ring. Each of these groups may have a substituent at any position, for example, an alkyl group (including a cycloalkyl group and an aralkyl group, preferably having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, Particularly preferably, it has 1 to 8 carbon atoms, for example, methyl, ethyl, n-propyl, iso-propyl, n-butyl, tert-butyl, n-heptyl, n-octyl, n-decyl, n-undecyl, n-
Hexadecyl, cyclopropyl, cyclopentyl, cyclohexyl, benzyl, phenethyl and the like can be mentioned. ), An alkenyl group (preferably having 2 to 20 carbon atoms, more preferably having 2 to 12 carbon atoms, and particularly preferably having 2 carbon atoms.
-8, for example, vinyl, allyl, 2-butenyl,
3-pentenyl and the like. ), An alkynyl group (preferably having 2 to 20 carbon atoms, more preferably having 2 to 1 carbon atoms)
2, particularly preferably having 2 to 8 carbon atoms, such as propargyl and 3-pentynyl. ), An aryl group (preferably having 6 to 30 carbon atoms, more preferably having 6 to 20 carbon atoms, particularly preferably having 6 to 12 carbon atoms, such as phenyl, p-tolyl, o-aminophenyl, and naphthyl) ), An amino group (preferably having 0 to 20 carbon atoms, more preferably 0 to 10 carbon atoms, particularly preferably 0 to 6 carbon atoms, such as amino, methylamino, ethylamino, dimethylamino, diethylamino, Diphenylamino, dibenzylamino, etc.), imino group (preferably 1 to 20 carbon atoms, more preferably 1 to 18 carbon atoms, particularly preferably 1 to 1 carbon atoms).
2, for example, methylimino, ethylimino, propylimino, phenylimino and the like. ) An alkoxy group (preferably having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, particularly preferably having 1 to 8 carbon atoms, for example, methoxy, ethoxy, butoxy, etc.), an aryloxy group ( Preferably 6 to 2 carbon atoms
It has 0, more preferably 6 to 16 carbon atoms, particularly preferably 6 to 12 carbon atoms, and examples thereof include phenyloxy and 2-naphthyloxy. ), An acyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, for example, acetyl, benzoyl, formyl, pivaloyl and the like), and alkoxy. Carbonyl group (preferably having 2 carbon atoms)
-20, more preferably 2-16 carbon atoms, particularly preferably 2-12 carbon atoms, for example, methoxycarbonyl, ethoxycarbonyl and the like. ), An aryloxycarbonyl group (preferably having 7 to 20 carbon atoms, more preferably having 7 to 16 carbon atoms, and particularly preferably having 7 to carbon atoms.
10, for example, phenyloxycarbonyl and the like. ), An acyloxy group (preferably having 1 to 1 carbon atoms)
20, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 10 carbon atoms, for example, acetoxy, benzoyloxy and the like. ), An acylamino group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably having 1 to 10 carbon atoms, such as acetylamino and benzoylamino), and an alkoxycarbonylamino group. (Preferably having 2 to 20 carbon atoms,
More preferably, it has 2 to 16 carbon atoms, particularly preferably 2 to 12 carbon atoms, for example, methoxycarbonylamino and the like. ), An aryloxycarbonylamino group (preferably having 7 to 20 carbon atoms, more preferably having 7 carbon atoms)
To 16, particularly preferably 7 to 12 carbon atoms, such as phenyloxycarbonylamino. ), A sulfonylamino group (preferably having 1 to 2 carbon atoms)
0, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, for example, methanesulfonylamino,
Benzenesulfonylamino and the like. ), A sulfamoyl group (preferably having 0 to 20 carbon atoms, more preferably 0 to 16 carbon atoms, and particularly preferably 0 to 12 carbon atoms, for example, sulfamoyl, methylsulfamoyl,
Dimethylsulfamoyl, phenylsulfamoyl and the like. ), A carbamoyl group (preferably having 1 carbon atom)
-20, more preferably 1-16 carbon atoms, particularly preferably 1-12 carbon atoms, for example, carbamoyl, methylcarbamoyl, diethylcarbamoyl, phenylcarbamoyl and the like. ), An alkylthio group (preferably having 1 to 20 carbon atoms, more preferably having 1 to 16 carbon atoms, particularly preferably having 1 to 12 carbon atoms, and examples thereof include methylthio and ethylthio), and an arylthio group (preferably C6-C20, more preferably C6-
16, particularly preferably having 6 to 12 carbon atoms, for example,
Phenylthio and the like. ), A sulfonyl group (preferably having 1 to 20 carbon atoms, more preferably having 1 to 1 carbon atoms)
6, particularly preferably having 1 to 12 carbon atoms, for example, methanesulfonyl, tosyl and the like. ), A sulfinyl group (preferably having 1 to 20 carbon atoms, more preferably having 1 to 16 carbon atoms, particularly preferably having 1 to 12 carbon atoms,
For example, methanesulfinyl, benzenesulfinyl and the like can be mentioned. ), Ureido group (preferably having 1 to carbon atoms)
20, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, for example, ureide, methylureide, phenylureide and the like. ), A phosphoric amide group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms,
For example, diethylphosphoric amide, phenylphosphoric amide and the like can be mentioned. ), Hydroxyl, mercapto,
Halogen atom (for example, fluorine atom, chlorine atom, bromine atom, iodine atom), cyano group, sulfo group, sulfino group, carboxyl group, phosphono group, phosphino group, nitro group, hydroxamic acid group, hydrazino group, heterocyclic group ( For example, imidazolyl, benzimidazolyl, thiazolyl, benzothiazolyl, carbazolyl, pyridyl, furyl, piperidyl, morpholino and the like can be mentioned.

Among the above groups, groups capable of forming a salt, such as a hydroxyl group, a mercapto group, a sulfo group, a sulfino group, a carboxyl group, a phosphono group and a phosphino group, may be salts. These substituents may be further substituted. When there are two or more substituents, they may be the same or different. As the substituent, preferably, an alkyl group, an aralkyl group, an alkoxy group, an aryl group, an alkylthio group, an acyl group, an acylamino group, an imino group, a sulfamoyl group, a sulfonyl group, a sulfonylamino group, a ureido group, an amino group, a halogen atom, and nitro Group, heterocyclic group,
Alkoxycarbonyl group, hydroxyl group, sulfo group,
A carbamoyl group or a carboxyl group, more preferably an alkyl group, an alkoxy group, an aryl group, an alkylthio group, an acyl group, an acylamino group, an imino group, a sulfonylamino group, a ureido group, an amino group, a halogen atom, a nitro group, or a heterocyclic ring. Group, alkoxycarbonyl group, hydroxyl group, sulfo group, carbamoyl group, carboxyl group, more preferably alkyl group, alkoxy group, aryl group, alkylthio group, acylamino group, imino group, ureido group, amino group, heterocyclic group , An alkoxycarbonyl group, a hydroxy group, a sulfo group, a carbamoyl group, and a carboxyl group. The amidino group includes those having a substituent. Examples of the substituent include an alkyl group (each group such as methyl, ethyl, pyridylmethyl, benzyl, phenethyl, carboxybenzyl, and aminophenylmethyl), and an aryl group (phenyl, groups such as p-tolyl, naphthyl, o-aminophenyl, o-methoxyphenyl), heterocyclic groups (2-thiazolyl, 2-pyridyl, 3
-Pyridyl, 2-furyl, 3-furyl, 2-thieno, 2
-Imidazolyl, benzothiazolyl, carbazolyl, etc.).

[0124] oxygen atom represented by J _31, examples of the divalent linking group containing a sulfur atom or a nitrogen atom one or more, for example, include the following. Also, a combination of these may be used.

[0125]

Embedded image

Here, Re and Rf are each the same as R
This is synonymous with the contents defined for a to Rd.

The aromatic hydrocarbon group represented by H ₃₁ Ar preferably has 6 to 30 carbon atoms, more preferably a monocyclic or condensed aryl group having 6 to 20 carbon atoms. , Phenyl, naphthyl and the like, with phenyl being particularly preferred. The aromatic heterocyclic group represented by H ₃₁ Ar is a 5- to 10-membered unsaturated heterocyclic group containing at least one atom of N, O and S;
The hetero ring in these groups may be a single ring or may form a condensed ring with another ring. The heterocycle in such a heterocyclic group is preferably a 5- to 6-membered aromatic heterocycle, and a benzo-fused ring thereof, more preferably a 5- to 6-membered aromatic heterocycle containing a nitrogen atom, and It is a benzo-fused ring, more preferably a 5- to 6-membered aromatic heterocycle containing 1 to 2 nitrogen atoms, and the benzo-fused ring.

Specific examples of the heterocyclic group include, for example, thiophene, furan, pyrrole, imidazole, pyrazole, pyridine, pyrazine, pyridazine, triazole,
Triazine, indole, indazole, purine, thiadiazole, oxadiazole, quinoline, phthalazine, naphthyridine, quinoxaline, quinazoline, cinnoline, pteridine, acridine, phenanthroline, phenazine, tetrazole, thiazole, oxazole,
Examples include groups derived from benzimidazole, benzoxazole, benzothiazole, benzothiazoline, benzotriazole, tetrazaindene, carbazole, and the like. Preferably as a heterocyclic group, imidazole, pyrazole, pyridine, pyrazine, indole, indazole, thiadiazole, oxadiazole, quinoline, phenazine, tetrazole, thiazole, oxazole, benzimidazole, benzoxazole, benzothiazole, benzothiazoline, benzotriazole, Tetrazaindene, a group consisting of carbazole, more preferably imidazole, pyridine, pyrazine, quinoline, phenazine, tetrazole, thiazole, benzoxazole, benzimidazole, benzothiazole, benzothiazoline, benzotriazole,
And groups derived from carbazole.

The aromatic hydrocarbon group and the aromatic heterocyclic group represented by H ₃₁ Ar may have a substituent. Examples of the substituent include the same as those described as the substituent for T _31. And the preferred range is also the same. These substituents may be further substituted, and when there are two or more substituents, each may be the same or different. The group represented by H ₃₁ Ar is preferably an aromatic heterocyclic group.

[0130] Ra, Rb, Rc, aliphatic hydrocarbon groups represented by Rd, aryl group and heterocyclic group, an aliphatic hydrocarbon group At a the T _31, as an example of the aryl group and heterocyclic group The same can be mentioned, and the preferred range is also the same. The acyl group represented by Ra, Rb, Rc, and Rd is an aliphatic or aromatic group having 1 to 12 carbon atoms, and specific examples include acetyl, benzoyl, formyl, and pivaloyl. Ra and Rb, Rc
And a nitrogen-containing heterocyclic group formed by bonding between Rd and Rb or between Rb and Rd, a 3- to 10-membered saturated or unsaturated heterocyclic group (for example, a piperidine ring, a piperazine ring, an acridine ring, A cyclic group such as a pyrrolidine ring, a pyrrole ring, and a morpholine ring).

[0131] Specific examples of the acid anion as ion necessary to compensate for intramolecular charge, represented by M _31, for example, a halogen ion (e.g. chloride, bromide,
Iodine ion), p-toluenesulfonic acid ion, perchlorate ion, boron tetrafluoride ion, sulfate ion, methyl sulfate ion, ethyl sulfate ion, methanesulfonic acid ion, trifluoromethanesulfonic acid ion and the like.

The macrocyclic compound containing a hetero atom is a 9 or more-membered macrocyclic compound containing at least one of a nitrogen atom, an oxygen atom, a sulfur atom and a selenium atom as a hetero atom. As typical compounds, the following compounds have been synthesized as crown ethers by Pedersen in 1967, and since their unique properties have been reported, many have been synthesized. These compounds are C.I. J. Pedersen, Journal
al of American chemical S
ociety vol. 86 (2495), 7017-
7036 (1967); W. Gokel, S.M. H,
Korzeniowski, “Macrocyclic
polyether synthesis ", Spri
nger-Verlag. (1982), Oda, Shono,
Edited by Tabushi, "Chemistry of Crown Ethers"
8), Tabushi et al. “Host-Guest” Kyoritsu Publishing (197)
9), Sasaki, Koga “Synthetic Organic Chemistry” Vol 45
(6), 571-582 (1987). Specific examples of these macrocyclic compounds containing a hetero atom include JP-A-2000-347343, paragraph 0030-
0037.

The supersensitizer according to the present invention is contained in an emulsion layer containing an organic silver salt and silver halide grains in an amount of 0.0
It is preferably used in the range of from 01 to 1.0 mol. Particularly preferably, the amount is in the range of 0.01 to 0.5 mol per mol of silver.

Examples of the reducing agent for the organic silver salt used in the present invention are described in US Pat. Nos. 3,770,448 and 3,77.
No. 3,512, No. 3,593,863, and RD1
7029 and 29996, and can be appropriately selected from known reducing agents. When an aliphatic silver carboxylate is used as the organic silver salt, two or more phenol groups are used. Is an alkylene group or a sulfur-linked polyphenol, particularly an alkyl group (eg, a methyl group, an ethyl group, a propyl group, a t-butyl group, a cyclohexyl group, etc.) at at least one position adjacent to the hydroxy-substituted position of the phenol group. Alternatively, bisphenols in which two or more phenol groups substituted with an acyl group (for example, an acetyl group or a propionyl group) are linked by an alkylene group or sulfur, for example, a compound represented by the following general formula (A) are preferable.

[0135]

Embedded image

In the formula, R is a hydrogen atom or a group having 1 to 1 carbon atoms.
10 alkyl groups (eg, isopropyl, butyl,
2,4,4-trimethylpentyl), and R ′ and R ″ represent an alkyl group having 1 to 5 carbon atoms (eg, methyl, ethyl, t-butyl).

In addition, US Pat. No. 3,589,903
No. 4,021,249 or British Patent No. 1,
Nos. 486,148 and JP-A-51-51933.
No., No. 50-36110, No. 50-116023,
No. 52-84727 or JP-B-51-35727
Polyphenol compounds described in the publication, for example,
2,2'-dihydroxy-1,1'-binaphthyl, 6,
6'-dibromo-2,2'-dihydroxy-1,1'-
Bisnaphthols described in U.S. Pat. No. 3,672,904 to Binaphthyl and the like, furthermore, for example, 4-benzenesulfonamidophenol, 2-benzenesulfonamidophenol, 2,6-dichloro-4-benzenesulfone Sulfonamidophenol or sulfonamidonaphthols as described in U.S. Pat. No. 3,801,321 such as amidophenol and 4-benzenesulfonaminaphthol can also be mentioned.

The amount of the reducing agent including the compound represented by formula (A) is preferably 1 × 1 per mol of silver.
It is from 0 ^-2 to 10 mol, especially from 1 x 10 ^{-2 to} 1.5 mol.

The amount of the reducing agent used in the photothermographic material of the present invention varies depending on the type of the organic silver salt, the reducing agent, and other additives. 05 mol to 10 mol, preferably 0.1 mol to 3 mol
Molar is appropriate. Further, within this range, two or more of the above-mentioned reducing agents may be used in combination. In the present invention, it is preferable that the reducing agent is added and mixed with a photosensitive emulsion solution composed of photosensitive silver halide and organic silver salt particles and a solvent immediately before coating and coating is performed, because photographic performance fluctuation due to stagnation time is small, which is preferable. is there.

The binder suitable for the photothermographic material of the present invention is transparent or translucent, generally colorless, and includes natural polymer synthetic resins, polymers and copolymers, and other film-forming media such as gelatin, gum arabic, and polyvinyl alcohol. , Hydroxyethyl cellulose, cellulose acetate, cellulose acetate butyrate,
Polyvinylpyrrolidone, casein, starch, and also vinyl chloride, vinyl acetate, vinyl alcohol, maleic acid,
Polymers or copolymers containing ethylenically unsaturated monomers such as acrylic acid, acrylic acid esters, vinylidene chloride, acrylonitrile, methacrylic acid, methacrylic acid esters, styrene, butadiene, ethylene, vinyl butyral, vinyl acetal, and vinyl ether as constituent units Compounds, polyurethane resins and various rubber resins. Further, a phenol resin, an epoxy resin, a polyurethane curable resin, a urea resin, a melamine resin, an alkyd resin, a formaldehyde resin, a silicone resin, an epoxy-polyamide resin, a polyester resin and the like can be mentioned. These resins are described in detail in "Plastic Handbook" published by Asakura Shoten. Typical examples thereof include polyvinyl chloride, copoly (styrene-maleic anhydride), copoly (styrene-acrylonitrile), copoly (styrene-butadiene), polyvinylacetals (for example, polyvinylformal and polyvinylbutyral), polyesters, and polyurethane. Kind,
Examples include phenoxy resins, polyvinylidene chloride, polyepoxides, polycarbonates, polyvinyl acetate, cellulose esters, polyamides, and the like. It may be hydrophilic or non-hydrophilic.

Among these, preferred binders for the photosensitive layer of the photothermographic material according to the present invention are polyvinyl acetal, and particularly preferred binder is polyvinyl butyral. Details will be described later. Further, for non-photosensitive layers such as an overcoat layer and an undercoat layer, particularly a protective layer and a back coat layer, polymers having a higher softening temperature, such as cellulose esters, particularly triacetyl cellulose, and a polymer such as cellulose acetate butyrate. preferable. In addition, if necessary, the above binders can be used in combination of two or more.

Such a binder is used in an effective range for functioning as a binder. Effective ranges can be readily determined by one skilled in the art. For example, as an index when at least the organic silver salt is retained in the image forming layer, the ratio of the binder to the organic silver salt is 15: 1 to 1:
2, particularly preferably in the range of 8: 1 to 1: 1. That is, the binder amount of the image forming layer is preferably 1.5 to 6 g / m ² . More preferably, it is 1.7 to 5 g / m ² . If it is less than 1.5 g / m ² , the density of the unexposed portion will increase significantly and may not be usable.

The glass transition temperature Tg of the binder used in the present invention is preferably from 70 ° C. to 105 ° C. Tg can be determined by measuring with a differential scanning calorimeter, and the intersection between the baseline and the slope of the endothermic peak is defined as the glass transition point.

In the present invention, the glass transition temperature (Tg)
Is "Polymer Handbook" by Brand Wrap and others II
It was determined by the method described on pages I-139 to III-179 (1966, Wiley & Sun).

T when the binder is a copolymer resin
g is obtained by the following equation. Tg (copolymer) (° C.) = V ₁ Tg ₁ + v ₂ Tg ₂ +...
During + v _n Tg _{n-type, v 1, v 2 ··· v} n represents the mass fraction of the monomer in the _{copolymer, Tg 1, Tg 2 ··· Tg} n are each in the copolymer It represents the Tg (° C.) of a homopolymer obtained from a monomer.

The precision of Tg calculated according to the above equation is ±
5 ° C. If a binder having a Tg of less than 70 ° C. is used, the intended effect cannot be obtained. Conversely, Tg is 1
The use of a binder having a temperature of not lower than 05 ° C. is not preferable because it hinders image formation and makes it impossible to obtain a sufficient maximum density.

The binder of the present invention has a Tg of 70 ° C.
~ 105 ° C, number average molecular weight of 1,000 ~ 1,000,
000, preferably 10,000 to 500,000, and a degree of polymerization of about 50 to 1,000.

The polymer or copolymer containing the above-mentioned ethylenically unsaturated monomer as a constituent unit will be described in more detail. As the ethylenically unsaturated monomer as a constituent unit of the polymer, alkyl acrylates, aryl acrylates Esters, alkyl methacrylates, aryl methacrylates, alkyl cyanoacrylates, aryl cyanoacrylates, and the like, and the alkyl group and the aryl group may be substituted. It may not be necessary, specifically, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl,
tert-butyl, amyl, hexyl, cyclohexyl, benzyl, chlorobenzyl, octyl, stearyl, sulfopropyl, N-ethyl-phenylaminoethyl, 2- (3-phenylpropyloxy) ethyl, dimethylaminophenoxyethyl, furfuryl, tetrahydrofur Furyl, phenyl, cresyl, naphthyl, 2-hydroxyethyl, 4-hydroxybutyl, triethylene glycol, dipropylene glycol, 2-methoxyethyl, 3-methoxybutyl, 2-acetoxyethyl, 2
-Acetoacetoxyethyl, 2-ethoxyethyl, 2-
iso-propoxyethyl, 2-butoxyethyl, 2-
(2-methoxyethoxy) ethyl, 2- (2-ethoxyethoxy) ethyl, 2- (2-butoxyethoxy) ethyl, 2-diphenylphosphorylethyl, ω-methoxypolyethylene glycol (addition mole number n = 6), allyl,
Dimethylaminoethyl methyl chloride salt and the like can be mentioned. In addition, the following monomers can be used. Vinyl esters: Specific examples thereof include vinyl acetate, vinyl propionate, vinyl butyrate,
Vinyl isobutyrate, vinyl caproate, vinyl chloroacetate, vinyl methoxy acetate, vinyl phenyl acetate, vinyl benzoate, vinyl salicylate, etc .; N-substituted acrylamides, N-substituted methacrylamides and acrylamide, methacrylamide: N
-As a substituent, methyl, ethyl, propyl, butyl, tert-butyl, cyclohexyl, benzyl, hydroxymethyl, methoxyethyl, dimethylaminoethyl, phenyl, dimethyl, diethyl, β-cyanoethyl, N- (2-acetoacetoxyethyl ), Diacetone and the like; olefins: for example, dicyclopentadiene,
Ethylene, propylene, 1-butene, 1-pentene, vinyl chloride, vinylidene chloride, isoprene, chloroprene, butadiene, 2,3-dimethylbutadiene and the like; styrenes: for example, methylstyrene, dimethylstyrene,
Trimethyl styrene, ethyl styrene, isopropyl styrene, tert-butyl styrene, chloromethyl styrene, methoxy styrene, acetoxy styrene, chloro styrene, dichloro styrene, bromo styrene, methyl vinyl benzoate; vinyl ethers: for example, methyl vinyl ether, butyl Vinyl ether, hexyl vinyl ether, methoxyethyl vinyl ether, dimethylaminoethyl vinyl ether, and the like; N-substituted maleimides: methyl, ethyl,
Propyl, butyl, tert-butyl, cyclohexyl, benzyl, n-dodecyl, phenyl, 2-methylphenyl, 2,6-diethylphenyl, 2-chlorophenyl and the like; and others, butyl crotonate, hexyl crotonate , Dimethyl itaconate, dibutyl itaconate, diethyl maleate, dimethyl maleate, dibutyl maleate, diethyl fumarate, dimethyl fumarate, dibutyl fumarate, methyl vinyl ketone,
Phenyl vinyl ketone, methoxyethyl vinyl ketone,
Glycidyl acrylate, glycidyl methacrylate,
Examples thereof include N-vinyloxazolidone, N-vinylpyrrolidone, acrylonitrile, methacrylonitrile, methylenemalononitrile, vinylidene chloride and the like.

Of these, particularly preferred examples include:
Examples include alkyl methacrylates, aryl methacrylates, and styrenes. Among such polymer compounds, it is preferable to use a polymer compound having an acetal group. Even a polymer compound having an acetal group is more preferably a polyvinyl acetal having an acetoacetal structure. For example, US Pat. Nos. 2,358,836 and 3,003,879
No. 2,828,204, UK Patent No. 771,1
No. 55 polyvinyl acetal.

The polymer compound having an acetal group according to the present invention includes a compound represented by the following general formula (V):
Particularly preferred.

[0151]

Embedded image

In the formula, R ₁ represents an alkyl group, a substituted alkyl group, an aryl group or a substituted aryl group, preferably a group other than the aryl group. R ₂ represents an unsubstituted alkyl group, a substituted alkyl group, an unsubstituted aryl group, a substituted aryl group, a -COR ₃ or -CONHR _3. R ₃ has the same meaning as R ₁ .

The unsubstituted alkyl group represented by R ₁ , R ₂ and R ₃ preferably has 1 to 20 carbon atoms, particularly preferably 1 to 6 carbon atoms. These may be linear or branched, and are preferably linear alkyl groups. Examples of such an unsubstituted alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a t-butyl group, and an n-butyl group.
-Amyl group, t-amyl group, n-hexyl group, cyclohexyl group, n-hepsyl group, n-octyl group, t-octyl group, 2-ethylhexyl group, n-nonyl group, n-decyl group, n-dodecyl And an n-octadecyl group, and particularly preferably a methyl group or a propyl group.

The unsubstituted aryl group may have 6 to 2 carbon atoms.
0 is preferable, and examples thereof include a phenyl group and a naphthyl group. Examples of the group that can be substituted for the above-mentioned alkyl group and aryl group include an alkyl group (eg, a methyl group, n
-Propyl group, t-amyl group, t-octyl group, n-nonyl group, dodecyl group, etc.), aryl group (eg, phenyl group), nitro group, hydroxyl group, cyano group, sulfo group, alkoxy group (eg, A methoxy group, etc.), an aryloxy group (eg, a phenoxy group), an acyloxy group (eg, an acetoxy group), an acylamino group (eg, an acetylamino group), a sulfonamide group (eg, a methanesulfonamide group), A sulfamoyl group (eg, a methylsulfamoyl group), a halogen atom (eg, a fluorine atom, a chlorine atom, a bromine atom), a carboxy group, a carbamoyl group (eg, a methylcarbamoyl group), an alkoxycarbonyl group (eg, methoxycarbonyl) Group), a sulfonyl group (eg, a methylsulfonyl group)
And the like. When there are two or more such substituents,
They may be the same or different. The total carbon number of the substituted alkyl group is preferably 1 to 20, and the total carbon number of the substituted aryl group is preferably 6 to 20.

As R ₂ , —COR ₃ (R ₃ is an alkyl group or an aryl group) and —CONHR ₃ (R ₃ is an aryl group) are preferable. a, b, and c are values in which the mass of each repeating unit is expressed in mol (mol)%, and a is 40 to 8
6 mol%, b is a number in the range of 0 to 30 mol%, c is a number in the range of 0 to 60 mol%, and a + b + c = 100 mol%. Particularly preferably, a is 50 to 86 mol%, and b is 5 to 86 mol%. 25 mol% and c is in the range of 0 to 40 mol%. Each of the repeating units having the respective composition ratios of a, b, and c may be constituted by only the same unit or may be constituted by different units.

As the polyurethane resin that can be used in the present invention, known resins such as polyester polyurethane, polyether polyurethane, polyether polyester polyurethane, polycarbonate polyurethane, polyester polycarbonate polyurethane, and polycaprolactone polyurethane can be used. For all polyurethanes shown here, -CO
_{OM, -SO 3 M, -OSO 3} M, -P = O (OM) 2,
-OP = O (OM) ₂ (M represents a hydrogen atom or an alkali metal base), -N (R) ₂ , -N ⁺ (R)
₃ (R represents a hydrocarbon group), an epoxy group, -SH,-
It is preferable to use one obtained by introducing at least one or more polar groups selected from CN or the like by copolymerization or addition reaction. The amount of such a polar group is 10 ^-1 to 10 ^-8 mol /
g, preferably 10 ^-2 to 10 ^-6 mol / g.
In addition to these polar groups, it is preferable to have at least one OH group at the terminal of the polyurethane molecule, that is, two or more OH groups in total. The OH group crosslinks with polyisocyanate as a curing agent to form a three-dimensional network structure, and therefore, it is preferable to include a large number of OH groups in the molecule. In particular, it is preferable that the OH group is located at the molecular terminal because the reactivity with the curing agent is high. The polyurethane preferably has three or more OH groups at the molecular terminals, particularly preferably four or more. In the present invention, when polyurethane is used, the glass transition temperature is 7
0 to 105 ° C, elongation at break is preferably 100 to 2000%, and stress at break is preferably 0.5 to 100 N / mm ² .

The polymer compound represented by the above general formula (V) of the present invention can be synthesized by a general synthesis method described in “Vinyl acetate resin” edited by Ichiro Sakurada (Polymer Chemistry Publishing Association, 1962). can do. The following are examples of typical synthesis methods, but the present invention is not limited to these typical synthesis examples.

Synthesis Example 1: Synthesis of P-1 20 g of polyvinyl alcohol (Gohsenol GH18) manufactured by Nippon Gosei Co., Ltd. and 180 g of pure water were charged, and dispersed in pure water so that the polyvinyl alcohol became a 10% by mass solution. After the temperature was raised to 95 ° C. to dissolve the polyvinyl alcohol, the solution was cooled to 75 ° C. to prepare an aqueous solution of polyvinyl alcohol, and 10% by mass of hydrochloric acid as an acid catalyst was added to the aqueous solution of polyvinyl alcohol. 6g
The mixture was added, and this was designated as a dripping liquid A. Then, a mixture 1 of butyraldehyde and acetaldehyde in a molar ratio of 1: 1 was prepared.
1.5 g was weighed and used as a dropping solution B. One 1000 ml four-necked flask equipped with a condenser and a stirrer
00 ml of pure water was added, heated to 85 ° C., and vigorously stirred. The dropping solution A and the dropping solution B were simultaneously dropped thereto over 2 hours with stirring using a dropping funnel kept at 75 ° C. At this time, the reaction was carried out while paying attention to the stirring speed while preventing fusion of precipitated particles. After dropping, 10
7 g of hydrochloric acid (mass%) was added, and the mixture was stirred at a temperature of 85 ° C. for 2 hours to sufficiently react. Thereafter, the mixture was cooled to 40 ° C., neutralized with sodium bicarbonate, washed with water 5 times, filtered, and the polymer was taken out and dried to obtain P-1. When Tg of the obtained P-1 was measured using DSC,
Tg was 85 ° C.

In addition, other polymer compounds shown in Table 1 were synthesized in the same manner. The measurement of the glass transition temperature was performed as follows.

The binder used for the image forming layer was dissolved in MEK on a Teflon (registered trademark) plate, and each was applied using a wire bar so that the dry film thickness became 20 μm.
After drying, it was peeled off from the Teflon plate. About 10 mg of the peeled sample was placed in an aluminum pan, and the glass transition temperature of each sample was measured using a differential scanning calorimeter (EXSTAR 6000, manufactured by Seiko Denshi) according to JIS-K-7121. The heating conditions during the measurement are
The temperature was raised to 200 ° C. at 10 ° C./min, and the cooling to 0 ° C. was performed at 20 ° C./min.

These polymer compounds (polymers) may be used alone or as a blend of two or more. The above polymer is used as a main binder in the image forming layer of the present invention. The main binder as used herein means "a state in which the polymer accounts for 50% by mass or more of the total binder in the image forming layer". Therefore, 5 of all binders
Other polymers may be blended and used in a range of less than 0% by mass. These polymers are not particularly limited as long as they are solvents in which the polymer of the present invention is soluble. More preferably, polyvinyl acetate, polyacrylic resin, urethane resin and the like can be mentioned.

Hereinafter, the constitutions of the polymer compound and the comparative compound according to the present invention are shown. Note that Tg in the table is a value measured by a differential scanning calorimeter (DSC) manufactured by Seiko Electronics Industry Co., Ltd.

[0163]

[Table 1]

[0164]

Embedded image

In Table 1, Comparative-1 is B-79 (manufactured by Sorcia). In the invention, the image forming layer may contain an organic gelling agent. The organic gelling agent referred to here is, for example, a function of imparting a yield value to the system by adding it to an organic liquid, such as a polyhydric alcohol, to eliminate or reduce the fluidity of the system. A compound having the following formula:

In a preferred embodiment of the present invention, the coating solution for the image forming layer contains an aqueously dispersed polymer latex. In this case, it is preferable that 50% by mass or more of the total binder in the coating solution for the image forming layer is a polymer latex dispersed in water.

When the image forming layer according to the present invention contains a polymer latex, it is preferred that 50% by mass or more of the total binder in the image forming layer is a polymer latex, more preferably 70% by mass or more. is there.

The "polymer latex" according to the present invention is a polymer in which a water-insoluble hydrophobic polymer is 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 average particle size of the dispersed particles is 1 to 50,000 n.
m, 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,
It may have a broad particle size distribution or a monodisperse particle size distribution.

The polymer latex according to the present invention may be a so-called core / shell type latex other than a polymer latex having a normal uniform structure. In this case the core and shell may be preferred when different glass transition temperature. The minimum film formation temperature (MFT) of the polymer latex according to the present invention is preferably -30 to 90 ° C,
More preferably, it is about 0 to 70 ° C. Further, a film-forming auxiliary may be added to control the minimum film-forming temperature. The film-forming aid used in the present invention 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, "Synthesis of synthetic latex (Souichi Muroi, Polymer Publishing Association) Published (1970)) "
It is described in.

The polymer used in the polymer latex according to the present invention includes acrylic resin, vinyl acetate resin, polyester resin, polyurethane resin, rubber resin, vinyl chloride resin, vinylidene chloride resin, polyolefin resin, or a copolymer thereof. and so on. 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 polymer has a number average molecular weight of 5,000 to 1,000,000, preferably 10
About 000 to 100,000 is preferable. 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 latex according to the present invention comprises 25
Those having an equilibrium water content of 0.01 to 2% by mass or less at 60 ° C. and 60% RH are preferred, and more preferably 0.01 to 1% by mass. 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.

Specific examples of the polymer latex according to the present invention include a methyl methacrylate / ethyl acrylate / methacrylic acid copolymer latex, a methyl methacrylate / 2-ethylhexyl acrylate / styrene / acrylic acid copolymer latex, and a styrene / butadiene / acrylic acid copolymer. Latex, styrene / butadiene / divinylbenzene / methacrylic acid copolymer latex, methyl methacrylate / vinyl chloride / acrylic acid copolymer latex, vinylidene chloride / ethyl acrylate / acrylonitrile / methacrylic acid copolymer latex, and the like.

These polymers may be used alone or as a blend of two or more as necessary.
The polymer latex preferably contains a carboxylic acid component such as an acrylate or methacrylate component in an amount of about 0.1 to 10% by mass.

Further, if necessary, a hydrophilic polymer such as gelatin, polyvinyl alcohol, methylcellulose, hydroxypropylcellulose, carboxymethylcellulose and hydroxypropylmethylcellulose may be added in a range of 50% by mass or less of the whole binder. The addition amount of these hydrophilic polymers is preferably 30% by mass or less of the total binder in the photosensitive layer.

In the preparation of the coating solution for forming a photosensitive layer according to the present invention, the order of addition of the organic silver salt and the polymer latex dispersed in the aqueous solution may be either earlier or simultaneously. Good, but preferably later, the polymer latex.

It is preferable that an organic silver salt and further a reducing agent are mixed before the addition of the polymer latex. Further, in the present invention, after mixing the organic silver salt and the polymer latex, if the temperature for aging is too low, the coated surface state is impaired, and if the temperature is too high, there is a problem that fog rises. It is preferable to age at 30 ° C. to 65 ° C. for the above time. Further, the aging is preferably performed at 35 ° C. to 60 ° C., particularly preferably at 35 ° C. to 55 ° C. In order to maintain the temperature in this manner, it is only necessary to keep the temperature of the coating solution preparation tank or the like.

In the application of the coating solution for forming a photosensitive layer according to the present invention, it is preferable to use a coating solution obtained by mixing an organic silver salt and an aqueous dispersion of a polymer latex and then passing for 30 minutes to 24 hours. After mixing, the mixture is allowed to elapse from 60 minutes to 12 hours, particularly preferably from 120 minutes to 12 hours.
The use of a coating solution after 10 hours has elapsed.

Here, "after mixing" refers to a state after the organic silver salt and the aqueous latex-dispersed polymer latex have been added and the added materials have been uniformly dispersed.

In the present invention, it is known that the use of a crosslinking agent with respect to the binder improves the film formation and reduces development unevenness. Also has the effect of suppressing generation of.

Examples of the crosslinking agent used in the present invention include various crosslinking agents conventionally used for photographic light-sensitive materials, for example, aldehyde-based, epoxy-based, and ethyleneimine described in JP-A-50-96216. , Vinyl sulfone, sulfonic acid ester, acryloyl, carbodiimide, and silane compound-based cross-linking agents can be used. Preferred are the following isocyanate-based compounds, silane compounds, epoxy compounds, and acid anhydrides.

The following general formula (2) which is one of the preferable ones
The isocyanate-based and thioisocyanate-based cross-linking agents represented by Formula (1) will be described.

General formula (2) X = C = NL- (N = C = X) _{v In the} formula, v is 1 or 2, and L may be an alkylene, alkenylene, arylene group or alkylarylene group. X is a divalent linking group, and X is an oxygen or sulfur atom.

In the compound represented by the general formula (2), the aryl ring of the arylene group may have a substituent. Examples of preferred substituents are selected from halogen atoms (eg, bromine or chlorine atoms), hydroxy, amino, carboxyl, alkyl and alkoxy groups.

The isocyanate-based crosslinking agent is an isocyanate having at least two isocyanate groups and an adduct thereof (adduct), and more specifically, an aliphatic diisocyanate and an aliphatic compound having a cyclic group. Group diisocyanates, benzene diisocyanates, naphthalene diisocyanates, biphenyl isocyanates, diphenylmethane diisocyanates, triphenylmethane diisocyanates, triisocyanates, tetraisocyanates, adducts of these isocyanates and diisocyanates with these isocyanates 3
Adducts with polyhydric polyalcohols.

As specific examples, the isocyanate compounds described on pages 10 to 12 of JP-A-56-5535 can be used.

The adduct of an isocyanate and a polyalcohol has a particularly high ability to improve interlayer adhesion and to prevent delamination, image shift and generation of bubbles. Such isocyanates may be located in any part of the photothermographic material.
For example, in the support (especially when the support is paper, it can be included in the size composition), the photosensitive layer side of the support such as a photosensitive layer, a surface protective layer, an intermediate layer, an antihalation layer, and an undercoat layer It can be added to any layer, and can be added to one or more of these layers.

As the thioisocyanate crosslinking agent that can be used in the present invention, a compound having a thioisocyanate structure corresponding to the above isocyanates is also useful.

The amount of the crosslinking agent used in the present invention ranges from 0.001 to 2 mol, preferably from 0.005 to 0.5 mol, per 1 mol of silver.

The isocyanate compound and thioisocyanate compound which can be contained in the present invention are:
Although it is preferable that the compound functions as the above-mentioned cross-linking agent, v may be zero (0) in the above-mentioned general formula, that is, a compound having only one such functional group may give good results.

Examples of silane compounds that can be used as a crosslinking agent in the present invention include compounds represented by the following general formula (3) or (4) disclosed in Japanese Patent Application No. 2000-77904.

[0192]

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In these general formulas, R ¹ , R ² ,
R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ⁸ each may be a linear, branched or cyclic alkyl group having 1 to 30 carbon atoms (methyl group, ethyl group, butyl group, Octyl group, dodecyl group, cycloalkyl group, etc.), alkenyl group (propenyl group, butenyl group, nonenyl group, etc.), alkynyl group (acetylene group, bisacetylene group, phenylacetylene group, etc.), aryl group or heterocyclic group (phenyl) Group, naphthyl group, tetrahydropyran group, pyridyl group, furyl group, thiophenyl group, imidazole group, thiazole group,
Thiadiazole group, oxadiazole group, etc.), and the substituent may have either an electron-withdrawing substituent or an electron-donating substituent.

It is preferable that at least one of the substituents selected from R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ⁸ is a diffusion-resistant group or an adsorptive group. Preferably, R ² is a diffusion-resistant group or an adsorptive group.

The diffusion resistant group is preferably an aliphatic group having 6 or more carbon atoms or an aryl group having an alkyl group having 3 or more carbon atoms, which is also called a ballast group. Diffusion resistance depends on the amount of binder and crosslinking agent used,
By introducing a diffusion-resistant group, the movement distance within the molecule at room temperature can be suppressed, and the reaction over time can be suppressed.

The epoxy compound only needs to have one or more epoxy groups, and there is no limitation on the number, molecular weight, and the like of the epoxy groups. The epoxy group is preferably contained in the molecule as a glycidyl group via an ether bond or an imino bond. Epoxy compounds are monomers,
It may be any of an oligomer, a polymer and the like, and the number of epoxy groups present in the molecule is usually about 1 to 10, preferably 2 to 4. When the epoxy compound is a polymer, it may be a homopolymer or a copolymer, and a particularly preferable range of the number average molecular weight Mn is about 2000 to 20,000.

L ₁ , L ₂ , L ₃ and L _{4 each} represent a divalent linking group, for example, —CH ₂ —, —CF ₂ —, ＝ CF—,
-O- group, -S- group, -NH- group, -OCO- group, -C
ONH- represents group, -SO ₂ NH- group, polyoxyalkylene group, thiourea group, a polymethylene group or those combination of these groups, and the like.

M and n represent an integer of 1 to 3, m + n is 4, p1 and p2 are integers of 1 to 3, q1 and q2 are 0, 1 or 2, p1 + q1 and p2 + q
2 is 3, and r1 and t represent 0 or an integer of 1 to 1000.

As the epoxy compound used in the present invention, a compound represented by the following general formula (5) is preferable.

[0200]

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In the general formula (5), the substituent of the alkylene group represented by R is preferably a group selected from a halogen atom, a hydroxyl group, a hydroxyalkyl group and an amino group. It is preferable that the linking group represented by R has an amide linking moiety, an ether linking moiety, and a thioether linking moiety. Examples of the divalent linking group represented by _{X -SO 2 -, - SO 2} NH -, - S -, - O-, or -
NR'- is preferred. Here, R 'is a monovalent group, and is preferably an electron withdrawing group.

These epoxy compounds may be used alone or in combination of two or more. The addition amount is not particularly limited, but is preferably in the range of 1 × 10 ⁻⁶ to 1 × 10 ⁻² mol / m ² , and more preferably in the range of 1 × 10 ⁻⁵ to 1 × 10 ⁻³ mol / m ² . It is.

In the present invention, the epoxy compound can be added to an arbitrary layer on the photosensitive layer side of the support such as a photosensitive layer, a surface protective layer, an intermediate layer, an antihalation layer, and an undercoat layer. It can be added to one or more layers. Also, it can be added to any layer on the opposite side of the support from the photosensitive layer. In the case of a photosensitive material having a photosensitive layer on both sides, any layer may be used.

The acid anhydride used in the present invention is a compound having at least one acid anhydride group represented by the following structural formula.

-CO-O-CO- The acid anhydride used in the present invention has one such acid anhydride group.
The number and molecular weight of the acid anhydride groups are not particularly limited as long as they have at least one, but a compound represented by the general formula (B) is preferable.

[0206]

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In the general formula (B), Z represents an atomic group necessary for forming a monocyclic or polycyclic system. These ring systems may be unsubstituted or substituted. Examples of the substituent include an alkyl group (for example, methyl, ethyl, hexyl) and an alkoxy group (for example, methoxy, ethoxy,
Octyloxy), an aryl group (eg, phenyl, naphthyl, tolyl), a hydroxy group, an aryloxy group (eg, phenoxy), an alkylthio group (eg, methylthio, butylthio), an arylthio group (eg, phenylthio), an acyl group (eg, , Acetyl, propionyl, butyryl), a sulfonyl group (eg, methylsulfonyl, phenylsulfonyl), an acylamino group, a sulfonylamino group, an acyloxy group (eg, acetoxy, benzoxy), a carboxyl group, a cyano group, a sulfo group, and an amino group. included. As the substituent, those not containing a halogen atom are preferable.

These acid anhydrides may be used alone or in combination of two or more. The amount of addition is not particularly limited, but is preferably in the range of 1 × 10 ⁻⁶ to 1 × 10 ⁻² mol / m ² , and more preferably 1 × 10 ⁻⁵ to 1 × 10 ⁻³ mol / m 2.
It is in the range of ² .

In the present invention, the acid anhydride can be added to any layer on the photosensitive layer side of the support such as a photosensitive layer, a surface protective layer, an intermediate layer, an antihalation layer and an undercoat layer. It can be added to one layer or two or more layers. Further, it may be added to the same layer as the epoxy compound.

In the present invention, the surface protective layer on the backing layer side and / or the image forming layer side preferably contains colloidal inorganic fine particles. Colloidal inorganic fine particles are mainly composed of silicon, aluminum, titanium, indium, yttrium, tin, antimony, zinc, nickel, copper,
Oxides selected from iron, cobalt, manganese, molybdenum, niobium, zirconium, vanadium, alkali metals, alkaline earth metals and the like are preferred. Among them, silicon oxide (colloidal silica) is more preferable in terms of transparency and hardness.

The above-mentioned colloidal inorganic fine particles refer to inorganic fine particles having a number average diameter of 1 nm to 100 nm.
5 nm to 50 nm is more preferable. The number average diameter referred to here is an average diameter obtained by dividing a one-dimensional length (length in which particles are arranged in one line) by the number, and is described in, for example, pages 58 to 59 of a fine particle handbook (Asakura Shoten). Can be obtained by the following definition formula.

The colloidal inorganic fine particles of the present invention include, for example,
Silicon oxide is commercially available from Nissan Chemical Industries, Ltd., and is available from Snowtex C, Snowtex N, Snowtex O, Snowtex S, Snowtex O.
L, organosilica sol XBA-ST, MIBK-S
T, MA-ST-M, IPA-ST and the like can be used.

The amount of the colloidal inorganic fine particles of the present invention to be added is preferably 5 to 50 with respect to the added protective layer binder.
% By mass is preferable, and 25 to 45% by mass is more preferable.
If it is less than this, the desired effect cannot be obtained, and if it is more than this, the film brittleness deteriorates.

In the present invention, the effect of the present invention can be further enhanced by using a silver saving agent.

The silver saving agent used in the present invention is
A compound capable of reducing the amount of silver required to obtain a constant silver image density. Although there are various possible mechanisms for the function of reducing the function, a compound having a function of improving the covering power of the developed silver is preferable. Here, the covering power of the developed silver means an optical density per unit amount of silver.

Examples of the silver saving agent include hydrazine derivative compounds represented by the following general formula (H), vinyl compounds represented by the following general formula (G), and quaternary onium compounds represented by the following general formula (P) Are preferred examples.

[0219]

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[0218]

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In the general formula (H), A ₀ represents an aliphatic group, an aromatic group, a heterocyclic group or a -G ₀ -D ₀ group which may have a substituent, and B ₀ represents a blocking group. , A ₁ , A
₂ represents a hydrogen atom, or one represents a hydrogen atom and the other represents an acyl group, a sulfonyl group, or an oxalyl group. here,
G ₀ is a —CO— group, a —COCO— group, a —CS— group, a —C
(= NG ₁ D ₁ ) —, —SO—, —SO ₂ — or —
A P (O) (G ₁ D ₁ ) — group, wherein G ₁ is a mere bond;
—O—, —S— or —N (D ₁ ) —, wherein D ₁ represents an aliphatic group, an aromatic group, a heterocyclic group or a hydrogen atom, and a plurality of D ₁ are present in the molecule If so, they may be the same or different. D ₀ represents a hydrogen atom, an aliphatic group, an aromatic group, a heterocyclic group, an amino group, an alkoxy group, an aryloxy group, an alkylthio group, or an arylthio group. Preferred examples of D ₀ include a hydrogen atom, an alkyl group, an alkoxy group, and an amino group.

In the general formula (H), the aliphatic group represented by A ₀ preferably has 1 to 30 carbon atoms, and particularly has a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms. Preferably, for example, a methyl group, an ethyl group, a t-butyl group,
Octyl group, cyclohexyl group, benzyl group, and the like, and further suitable substituents (for example, aryl group,
Alkoxy, aryloxy, alkylthio, arylthio, sulfoxy, sulfonamido, sulfamoyl, acylamino, ureido, etc.).

In formula (H), the aromatic group represented by A ₀ is preferably a monocyclic or condensed-ring aryl group, for example, a benzene ring or a naphthalene ring, and a heterocyclic group represented by A _0. The group is preferably a heterocyclic ring containing at least one heteroatom selected from nitrogen, sulfur, and oxygen atom in a single ring or a condensed ring, for example, a pyrrolidine ring, an imidazole ring, a tetrahydrofuran ring, a morpholine ring, a pyridine ring, a pyrimidine ring, Examples include a quinoline ring, a thiazole ring, a benzothiazole ring, a thiophene ring and a furan ring. Aromatic groups A _0, heterocyclic group or -G ₀ -D ₀ group may have a substituent. Particularly preferred as A ₀ are an aryl group and a -G ₀ -D ₀ group.

In the general formula (H), A ₀ preferably contains at least one diffusion-resistant group or silver halide-adsorbing group. As the diffusion-resistant group, a ballast group commonly used in immobile photographic additives such as couplers is preferable, and as the ballast group, a photographically inactive alkyl group, alkenyl group, alkynyl group, alkoxy group, phenyl And a phenoxy group, an alkylphenoxy group, and the like. The total number of carbon atoms in the substituent is preferably 8 or more.

In the formula (H), examples of the silver halide adsorption promoting group include thiourea, thiourethane, mercapto, thioether, thione, heterocyclic, thioamide heterocyclic, mercapto heterocyclic and special groups. 64-9
No. 0439.

In the general formula (H), B ₀ represents a blocking group, preferably a -G ₀ -D ₀ group, and G ₀ represents-
CO- group, -COCO- group, -CS- group, -C (= NG
₁ D ₁₎ - group, -SO- group, -SO ₂ - group or -P (O)
(G ₁ D ₁ ) — represents a group. Preferred G ₀ is -CO-
Group, -COCO- group, G ₁ is a mere bond,
—O—, —S— or —N (D ₁ ) —, wherein D ₁ represents an aliphatic group, an aromatic group, a heterocyclic group or a hydrogen atom, and a plurality of D ₁ are present in the molecule If so, they may be the same or different. D ₀ represents a hydrogen atom, an aliphatic group, an aromatic group, a heterocyclic group, an amino group, an alkoxy group, an aryloxy group, an alkylthio group, or an arylthio group, and preferred D ₀ is a hydrogen atom, an alkyl group, an alkoxy group, And an amino group. A ₁ and A ₂ are both hydrogen atoms, or one is a hydrogen atom and the other is an acyl group (acetyl group, trifluoroacetyl group, benzoyl group, etc.), a sulfonyl group (methanesulfonyl group, toluenesulfonyl group, etc.), or an oxalyl group (Such as an ethoxalyl group).

The compounds represented by formula (H) of the present invention can be easily synthesized by known methods. For example, U.S. Pat.
It can be synthesized with reference to 496,695.

Other hydrazine derivatives that can be preferably used include compounds H-1 to H-29 described in US Pat. No. 5,545,505, columns 11 to 20, and US Pat. No. 5,464,738, column 9 Compounds 1 to 12 described in Nos. 1 to 11. These hydrazine derivatives can be synthesized by a known method.

In the general formula (G), X and R are represented in the form of cis. However, the general formula (G) includes X and R in the form of trans. This is the same in the structural representation of a specific compound.

In the general formula (G), X represents an electron-withdrawing group, and W is a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a heterocyclic group, a halogen atom,
Acyl, thioacyl, oxalyl, oxyoxalyl, thiooxalyl, oxamoyl, oxycarbonyl, thiocarbonyl, carbamoyl, thiocarbamoyl, sulfonyl, sulfinyl, oxysulfinyl, thiosulfinyl, sulfamoyl Group, oxysulfinyl group, thiosulfinyl group, sulfinamoyl group, phosphoryl group, nitro group, imino group, N-carbonylimino group, N-sulfonylimino group, dicyanethylene group, ammonium group, sulfonium group, phosphonium group, pyrylium group, Represents an immonium group.

R represents a halogen atom, a hydroxyl group, an alkoxy group, an aryloxy group, a heterocyclic oxy group, an alkenyloxy group, an acyloxy group, an alkoxycarbonyloxy group, an aminocarbonyloxy group, a mercapto group, an alkylthio group, an arylthio group, Organic or inorganic salts of ring thio group, alkenylthio group, acylthio group, alkoxycarbonylthio group, aminocarbonylthio group, hydroxyl group or mercapto group (for example, sodium salt, potassium salt, silver salt, etc.), amino group, alkyl Amino group, cyclic amino group (eg, pyrrolidino group), acylamino group, oxycarbonylamino group, heterocyclic group (5- to 6-membered nitrogen-containing heterocyclic ring, for example, benztriazolyl group, imidazolyl group, triazolyl group, tetrazolyl group Etc.), ureido groups, It represents a Ruhon'amido group. X and W, and X and R may be bonded to each other to form a cyclic structure. The ring formed by X and W includes, for example, pyrazolone, pyrazolidinone, cyclopentanedione, β-
Ketoractone, β-ketolactam and the like.

The general formula (G) will be further described.
The electron-withdrawing group represented by is a substituent whose substituent constant σp can take a positive value. Specifically, a substituted alkyl group (eg, halogen-substituted alkyl), a substituted alkenyl group (eg, cyanovinyl), a substituted / unsubstituted alkynyl group (eg, trifluoromethylacetylenyl, cyanoacetylenyl),
Substituted aryl group (cyanophenyl, etc.), substituted / unsubstituted heterocyclic group (pyridyl, triazinyl, benzoxazolyl, etc.), halogen atom, cyano group, acyl group (acetyl, trifluoroacetyl, formyl, etc.), thioacetyl group (Thioacetyl, thioformyl, etc.), oxalyl group (methyloxalyl, etc.), oxyoxalyl group (ethoxalyl, etc.), thiooxalyl group (ethylthiooxalyl, etc.), oxamoyl group (methyloxamoyl, etc.), oxycarbonyl group (ethoxycarbonyl, etc.) , Carboxyl group, thiocarbonyl group (such as ethylthiocarbonyl),
Carbamoyl group, thiocarbamoyl group, sulfonyl group,
Sulfinyl group, oxysulfonyl group (ethoxysulfonyl, etc.), thiosulfonyl group (ethylthiosulfonyl, etc.), sulfamoyl group, oxysulfinyl group (methoxysulfinyl, etc.), thiosulfinyl group (methylthiosulfinyl, etc.), sulfinamoyl group, phosphoryl group, nitro Group, imino group, N-carbonylimino group (N
-Acetylimino, etc.), N-sulfonylimino group (N-
Methanesulfonylimino, etc.), dicyanoethylene group, ammonium group, sulfonium group, phosphonium group, pyrylium group, immonium group, but heterocyclic ring in which ammonium group, sulfonium group, phosphonium group, immonium group, etc. form a ring Also included. σp
Substituents having a value of at least 0.30 are particularly preferred.

Examples of the alkyl group represented by W include methyl, ethyl, trifluoromethyl and the like, examples of the alkenyl group include vinyl, halogen-substituted vinyl and cyanovinyl, and examples of the alkynyl group include acetylenyl and cyanoacetylenyl. Examples of the aryl group include nitrophenyl, cyanophenyl, and pentafluorophenyl. Examples of the heterocyclic group include pyridyl, pyrimidyl, triazinyl, succinimide, tetrazolyl, triazolyl, imidazolyl, and benzoxazolyl. W is σ
A p-value is preferably a positive electron-withdrawing group, and more preferably, the value is 0.30 or more.

Of the above substituents for R, preferred are a hydroxyl group, a mercapto group, an alkoxy group, an alkylthio group, a halogen atom, an organic or inorganic salt of a hydroxyl group or a mercapto group, and a heterocyclic group. Examples thereof include an organic or inorganic salt of a hydroxyl group, an alkoxy group, a hydroxyl group or a mercapto group, and a heterocyclic group, and particularly preferably an organic or inorganic salt of a hydroxyl group or a mercapto group.

Of the substituents for X and W, those having a thioether bond in the substituent are preferable.

In the formula (P), Q represents a nitrogen atom or a phosphorus atom, R ₁ , R ₂ , R ₃ and R ₄ each represent a hydrogen atom or a substituent, and X ⁻ represents an anion. Note that R _{1 to} R
₄ may be connected to each other to form a ring.

As the substituent represented by R _{1 to} R ₄ , an alkyl group (methyl group, ethyl group, propyl group, butyl group,
Hexyl group, cyclohexyl group, etc., alkenyl group (allyl group, butenyl group, etc.), alkynyl group (propargyl group, butynyl group, etc.), aryl group (phenyl group, naphthyl group, etc.), heterocyclic group (piperidinyl group, piperazinyl group) , Morpholinyl group, pyridyl group, furyl group, thienyl group, tetrahydrofuryl group, tetrahydrothienyl group,
Sulfolanyl group), an amino group and the like.

The ring which may be formed by connecting R _{1 to} R ₄ to each other includes a piperidine ring, a morpholine ring, a piperazine ring,
Examples include a quinuclidine ring, a pyridine ring, a pyrrole ring, an imidazole ring, a triazole ring, and a tetrazole ring.

The groups represented by R _{1 to} R ₄ are a hydroxyl group,
It may have a substituent such as an alkoxy group, an aryloxy group, a carboxyl group, a sulfo group, an alkyl group and an aryl group. As R ₁ , R ₂ , R ₃ and R ₄ , a hydrogen atom and an alkyl group are preferred.

Examples of the anion represented by X ⁻ include inorganic and organic anions such as a halogen ion, a sulfate ion, a nitrate ion, an acetate ion and a p-toluenesulfonic acid ion.

The above quaternary onium compound can be easily synthesized according to a known method. For example, the above tetrazolium compound can be obtained from Chemical Reviews vol. 55
p. 335-483 can be referred to. The amount of the silver saving agent is in the range of 10 ^-5 to 1 mol, preferably 10 ^{-4 to} 5 × 10 ^-1 mol, per 1 mol of the organic silver salt.

The antifoggant and image stabilizer used in the photothermographic material of the present invention will be described.

As the reducing agent, a reducing agent having a proton, such as bisphenols or sulfonamidophenols, is mainly used. Thus, active species capable of extracting these hydrogens are generated to generate a reducing agent. It is preferable that a compound capable of inactivating the agent is contained.
Preferably, as the colorless photo-oxidizable substance, a compound capable of generating a free radical as a reactive species upon exposure is preferable.

Accordingly, any compound having these functions may be used, but an organic free radical consisting of a plurality of atoms is preferable. A compound having any structure may be used as long as it has such a function and does not cause any particular adverse effect on the silver salt photothermographic material.

The compounds that generate these free radicals may be carbocyclic or so as to have such a stability that the free radicals generated can be contacted with the reducing agent for a sufficient time to react with and inactivate them. Those having a heterocyclic aromatic group are preferred.

Representative of these compounds are the following biimidazolyl compounds and iodonium compounds.

Examples of the biimidazolyl compound include those represented by the following general formula (6).

[0246]

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In the formula, each of R ₁ , R ₂ and R ₃ (same or different) is an alkyl group (eg, methyl, ethyl, hexyl), an alkenyl group (eg, vinyl, allyl),
Alkoxy groups (eg, methoxy, ethoxy, octyloxy), aryl groups (eg, phenyl, naphthyl,
Tolyl), hydroxyl, halogen, aryloxy (eg, phenoxy), alkylthio (eg, methylthio, butylthio), arylthio (eg, phenylthio), acyl (eg, acetyl, propionyl, butyryl, valeryl), A sulfonyl group (eg, methylsulfonyl, phenylsulfonyl), an acylamino group, a sulfonylamino group, an acyloxy group (eg, acetoxy, benzoxy), a carboxyl group, a cyano group, a sulfo group, and an amino group.
Among these, more preferred substituents are an aryl group, an alkenyl group and a cyano group.

The above biimidazolyl compounds are disclosed in US Pat. No. 3,734,733 and British Patent 1,271,17.
It can be produced by the production method described in No. 7 and a method analogous thereto. Preferred specific examples are shown below.

[0249]

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[0250]

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Further, similarly suitable compounds include iodonium compounds represented by the following general formula (7).

[0252]

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In the formula, Q includes atoms necessary for completing a 5-, 6- or 7-membered ring, and the necessary atoms are selected from a carbon atom, a nitrogen atom, an oxygen atom and a sulfur atom. R
Each of ¹ , R ² and R ³ (same or different) is a hydrogen atom, an alkyl group (eg, methyl, ethyl, hexyl), an alkenyl group (eg, vinyl, allyl), an alkoxy group (eg, methoxy, ethoxy, Octyloxy), an aryl group (eg, phenyl, naphthyl, tolyl), a hydroxyl group, a halogen atom, an aryloxy group (eg, phenoxy), an alkylthio group (eg,
Methylthio, butylthio), arylthio groups (for example,
Phenylthio), acyl group (eg, acetyl, propionyl, butyryl, valeryl), sulfonyl group (eg, methylsulfonyl, phenylsulfonyl), acylamino group, sulfonylamino group, acyloxy group (eg, acetoxy, benzoxy), carboxyl group, cyano Group, sulfo group and amino group. Among these, more preferred substituents are an aryl group, an alkenyl group and a cyano group.

[0254] R ⁴ is acetate, benzoate, carboxylate group such as trifluoroacetate and O ^-
Is shown. W represents 0 or 1.

[0255] X ^- is an anionic counterion, as suitable ^{_{examples, CH 3 CO 2 -, CH}} 3 SO 3 - and PF ₆ ^- is.

The [0256] When R ³ is a sulfo group or a carboxyl group, W is 0, and R ⁴ is O ^-.

Incidentally, any of R ¹ , R ² and R ³ may be bonded to each other to form a ring. Among them, particularly preferred compounds are represented by the following general formula (8).

[0258]

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Here, R ¹ , R ² , R ³ , R ⁴ , X ⁻
And W represent the same as those in the general formula (7), and Y represents a carbon atom (-CH =; benzene ring) or a nitrogen atom (-N =; pyridine ring).

The above iodonium compounds are described in Org. Sy
n. , 1961 and "Advanced by Fieser.
Organic Chemistry "(Reinh
old, N .; Y. , 1961) and a method analogous thereto.

The amount of the compounds represented by the above general formulas (6) and (7) is 0.001 to 0.1 mol / m ² , preferably 0.005 to 0.05 mol / m ² . Range. The compound is used in the photosensitive material of the present invention.
Although it can be contained in any constituent layer, it is preferable to contain it in the vicinity of the reducing agent.

In the present invention, as the compound that inactivates the reducing agent and prevents the reducing agent from reducing the organic silver salt to silver, it is preferable that the reactive species is not a halogen atom. The compound which releases as an active species can also be used in combination with the compound of the present invention which releases an active species which is not a halogen atom. Many compounds capable of releasing a halogen atom as an active species are known, and a good effect can be obtained by using them in combination.

Specific examples of the compound which generates an active halogen atom include a compound represented by the following general formula (9).

[0264]

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In the general formula (9), Q represents an aryl group or a heterocyclic group. X ₁ , X ₂ and X ₃ represent a hydrogen atom, a halogen atom, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a sulfonyl group or an aryl group, at least one of which is a halogen atom. Y is -C
(= O) -, - SO- or -SO ₂ - represents a.

The aryl group represented by Q may be monocyclic or condensed, and is preferably a monocyclic or bicyclic aryl group having 6 to 30 carbon atoms (eg, phenyl, naphthyl, etc.)
And more preferably a phenyl group and a naphthyl group, and further preferably a phenyl group.

The heterocyclic group represented by Q is a 3- to 10-membered saturated or unsaturated heterocyclic group containing at least one atom of N, O or S, and these may be monocyclic. Alternatively, a condensed ring may be formed with another ring.

The heterocyclic group is preferably a 5- or 6-membered unsaturated heterocyclic group optionally having a condensed ring, and more preferably a 5- or 6-membered aromatic group optionally having a condensed ring. Group heterocyclic group. More preferably, it is a 5- or 6-membered aromatic heterocyclic group which may have a condensed ring containing a nitrogen atom, particularly preferably a condensed ring which may have a condensed ring containing 1 to 4 nitrogen atoms. And a 6-membered aromatic heterocyclic group. As the heterocycle in such a heterocyclic group, preferably, imidazole, pyrazole, pyridine, pyrimidine, pyrazine, pyridazine, triazole, triazine, indole, indazole,
Purine, thiadiazole, oxadiazole, quinoline, phthalazine, naphthyridine, quinoxaline, quinazoline, cinnoline, pteridine, acridine, phenanthroline, phenazine, tetrazole, thiazole, oxazole, benzimidazole, benzoxazole, benzothiazole, indolenine, tetrazaindene Yes, more preferably imidazole, pyridine, pyrimidine, pyrazine, pyridazine, triazole, triazine, thiadiazole, oxadiazole, quinoline, phthalazine, naphthyridine, quinoxaline, quinazoline, cinnoline, tetrazole, thiazole, oxazole, benzimidazole, benzoxazole, benz Thiazole and tetrazaindene, more preferably imidazole and pyridene. Down, pyrimidine, pyrazine,
Pyridazine, triazole, triazine, thiadiazole, quinoline, phthalazine, naphthyridine, quinoxaline, quinazoline, cinnoline, tetrazole, thiazole, benzimidazole and benzthiazole, particularly preferably pyridine, thiadiazole, quinoline and benzthiazole.

The aryl group and the heterocyclic group represented by Q may have a substituent in addition to -YC (X ₁ ) (X ₂ ) (X ₃ ). Group, alkenyl group, aryl group, alkoxy group, aryloxy group, acyloxy group, acyl group, alkoxycarbonyl group, aryloxycarbonyl group, acyloxy group,
Acylamino group, alkoxycarbonylamino group, aryloxycarbonylamino group, sulfonylamino group,
Sulfamoyl group, carbamoyl group, sulfonyl group, ureido group, phosphoric acid amide group, halogen atom, cyano group,
Sulfo group, carboxyl group, nitro group, heterocyclic group, more preferably alkyl group, aryl group, alkoxy group, aryloxy group, acyl group, acylamino group,
Alkoxycarbonylamino group, aryloxycarbonylamino group, sulfonylamino group, sulfamoyl group, carbamoyl group, ureido group, phosphoric acid amide group, halogen atom, cyano group, nitro group, heterocyclic group,
More preferred are an alkyl group, an aryl group, an alkoxy group, an aryloxy group, an acyl group, an acylamino group, a sulfonylamino group, a sulfamoyl group, a carbamoyl group, a halogen atom, a cyano group, a nitro group, and a heterocyclic group, and particularly preferred. An alkyl group, an aryl group, and a halogen atom.

X ₁ , X ₂ and X ₃ are preferably a halogen atom, a haloalkyl group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a carbamoyl group, a sulfamoyl group, a sulfonyl group and a heterocyclic group, more preferably A halogen atom, a haloalkyl group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, and a sulfonyl group, more preferably a halogen atom and a trihalomethyl group, and particularly preferably a halogen atom. Among the halogen atoms, a chlorine atom, a bromine atom and an iodine atom are preferred, a chlorine atom and a bromine atom are more preferred, and a bromine atom is particularly preferred.

Y is -C (= O)-, -SO-, -SO ₂
- represents preferably -SO ₂ - is.

The addition amount of these compounds is preferably within a range in which the increase in printout silver due to the formation of silver halide does not cause a problem, and is a maximum of 150% or less relative to the compound that does not generate active halogen radicals.
More preferably, it is preferably 100% or less.

In addition to the above-mentioned compounds, the photothermographic material of the present invention may contain a compound conventionally known as an antifoggant. The compound may be a compound that can be formed or a compound having a different fog prevention mechanism. For example, U.S. Patent Nos. 3,589,903 and 4,546,07
5, No. 4,452,885, JP-A-59-572.
No. 34, U.S. Pat. Nos. 3,874,946 and 4,7
56,999, JP-A-9-288328, JP-A-9-288
-90550. Further, other antifoggants include US Pat. No. 5,028,523 and European Patent No. 600,58.
7, 605,981 and 631,176.

The photothermographic material of the present invention, which forms a photographic image by heat development, is prepared by dispersing a toning agent for adjusting the color tone of silver, if necessary, in an ordinary (organic) binder matrix. It is preferred to contain.

Examples of suitable toning agents used in the present invention are R.
search Disclosure No. 17029
No. 4,123,282, US Pat.
No. 4,732, No. 3,846,136 and No. 4,021,249, for example, there are the following.

Imides (for example, succinimide, phthalimide, naphthalimide, N-hydroxy-1,8
-Naphthalimide); mercaptans (for example, 3-
Mercapto-1,2,4-triazole); phthalazinone derivatives or metal salts of these derivatives (for example, phthalazinone, 4- (1-naphthyl) phthalazinone, 6-chlorophthalazinone, 5,7-dimethyloxyphthalazinone, And 2,3-dihydro-1,4-phthalazinedione); phthalazine and phthalic acids (for example, phthalic acid,
-Methylphthalic acid, 4-nitrophthalic acid and tetrachlorophthalic acid); phthalazine and maleic anhydride, and phthalic acid, 2,3-naphthalenedicarboxylic acid or o-phenylene acid derivatives and anhydrides thereof (for example,
And a combination with at least one compound selected from phthalic acid, 4-methylphthalic acid, 4-nitrophthalic acid and tetrachlorophthalic anhydride. Particularly preferred toning agents are phthalazinone or a combination of phthalazine with phthalic acids and phthalic anhydrides.

As for the color tone of the output image for medical diagnosis, it is said that the cold tone of the image makes it easier for the reader of the radiograph to obtain a more accurate diagnosis and observation result of the recorded image. Here, the cool image tone is a pure black tone or a blue-black tone in which a black image is bluish, and the warm image tone is a warm black tone in which a black image is brownish. Say

The terms “cooler” and “warmer” regarding the color tone are defined as the minimum density Dmin and the optical density D = 1.
Hue angle h defined by JIS Z 8729 at 0
ab. Hue angle hab is JIS Z8
XYZ color system or tristimulus values X, Y,
JIS Z 8729 from Z or X ₁₀ , Y ₁₀ , Z ₁₀
Can be represented by hab = tan ^-1 (b ^* / a ^* ) using the color coordinates a ^* and b ^* of the L ^* a ^* b ^* color system defined by

In the present invention, when used as a medical image, the preferable range of hab is 180 ° <hab <27.
0 °, more preferably 200 ° <hab <27
0 °, most preferably 220 ° <hab <260 °.

In the present invention, the photothermographic material may be treated on the surface layer (even when a non-photosensitive layer is provided on the image forming layer side or on the opposite side of the image forming layer with the support interposed therebetween) before development. It is preferable to contain a matting agent in order to prevent the image after thermal development from being damaged, and it is preferable to contain the matting agent in an amount of 0.1 to 30% by mass based on the binder.

The material of the matting agent used in the present invention may be either an organic substance or an inorganic substance. For example, as inorganic substances, silica described in Swiss Patent No. 330,158, glass powder described in French Patent No. 1,296,995, etc., and alkali described in British Patent No. 1,173,181 etc. An earth metal or a carbonate such as cadmium or zinc can be used as a matting agent. Examples of organic substances include starch described in U.S. Pat. No. 2,322,037, Belgian Patent No. 625,451 and British Patent No. 981,198.
Derivatives, polyvinyl alcohol described in JP-B-44-3643 and the like, Swiss Patent No. 33
No. 0,158, polystyrene or polymethacrylate; U.S. Pat. No. 3,079,257; polyacrylonitrile; U.S. Pat. No. 3,022,16.
An organic matting agent such as polycarbonate described in No. 9 or the like can be used.

The matting agent used in the present invention preferably has an average particle size of 0.5 μm to 10 μm, more preferably 1.0 μm to 8.0 μm. The matting agent preferably has a variation coefficient of the particle size distribution of 50% or less, more preferably 40% or less, and particularly preferably 30% or less.

Here, the coefficient of variation of the particle size distribution is a value represented by the following equation. (Standard deviation of particle size) / (Average value of particle size) × 100 The method of adding the matting agent according to the present invention may be a method of dispersing in a coating solution in advance and applying the coating solution, or applying the coating solution. After that, a method of spraying a matting agent before the drying is completed may be used. When a plurality of types of matting agents are added, both methods may be used in combination. A preferred addition amount is 5 to 300 mg / m ² .

As the material of the support used in the photothermographic material according to the present invention, various polymer materials, glass, wool cloth,
Examples thereof include cotton cloth, paper, and metal (for example, aluminum). However, in terms of handling as an information recording material, a material that can be processed into a flexible sheet or roll is preferable.
Therefore, as the support in the photothermographic material of the present invention, a plastic film (for example, a cellulose acetate film, a polyester film, a polyethylene terephthalate film, a polyethylene naphthalate film, a polyamide film, a polyimide film, a cellulose triacetate film or a polycarbonate film) is preferable. In the present invention, a biaxially stretched polyethylene terephthalate film is particularly preferred. The thickness of the support is about 50 to 300 μm, preferably 70 to 180 μm.

In the present invention, a conductive compound such as a metal oxide and / or a conductive polymer can be contained in the constituent layer in order to improve the chargeability. These may be contained in any layer, but are preferably contained in a backing layer, a surface protective layer on the photosensitive layer side, an undercoat layer, and the like. In the present invention, US Pat.
The conductive compounds described in No. columns 14 to 20 are preferably used.

In particular, in the present invention, it was found that the effect of the present invention can be further enhanced by including a conductive metal oxide in the surface protective layer on the backing layer side. Here, the conductive metal oxide is a crystalline metal oxide particle, and generally includes those containing oxygen vacancies and those containing a small amount of heteroatoms forming a donor for the metal oxide used. It is particularly preferred because of its high conductivity, and the latter is particularly preferred because it does not give fog to the silver halide emulsion. Examples of metal oxide include ZnO, TiO _2, SnO _2, Al
₂ O ₃ , In ₂ O ₃ , SiO ₂ , MgO, BaO, MoO ₃ ,
V ₂ O ₅ or the like or a composite oxide thereof is particularly preferable.
nO, TiO ₂ and SnO ₂ are preferred. Examples of including heteroatoms include, for example, addition of Al, In, etc. to ZnO, addition of Sb, Nb, P, a halogen element, etc. to SnO ₂ , and addition of Nb, Ta, etc. to TiO ₂ . Is effective. The addition amount of these different atoms is 0.01 m
ol% to 30 mol% is preferable, but 0.1 mol
It is particularly preferable if it is 1% to 10 mol%. Further, a silicon compound may be added at the time of preparing fine particles for improving fine particle dispersibility and transparency. The metal oxide fine particles of the present invention have conductivity and have a volume resistivity of 10 ⁷ Ωcm.
Below, especially 10 ⁵ Ωcm or less. These oxides are described in JP-A-56-143431 and JP-A-56-120.
Nos. 519 and 58-62647. Furthermore, as described in JP-B-59-6235,
A conductive material in which the above-described metal oxide is attached to other crystalline metal oxide particles or fibrous materials (for example, titanium oxide) may be used.

The usable particle size is preferably 1 μm or less.
However, when it is 0.5 μm or less, the stability after dispersion is good.
Easy to use. Also, to minimize light scattering
When conductive particles of 0.3 μm or less are used,
The material can be formed, which is very preferable. Also
If the conductive metal oxide is acicular or fibrous, its length
Is preferably 30 μm or less and 1 μm or less in diameter, particularly preferably
Preferably, the length is less than 10μm and the diameter is less than 0.3μm.
The length / diameter ratio is 3 or more. In addition, SnO _Twoage
Is commercially available from Ishihara Sangyo Co., Ltd.
M, SN-100P, SN-100D, FSS10M
Which can be used.

The photothermographic material of the present invention has at least one photosensitive layer on a support. Although only the image forming layer may be formed on the support, it is preferable to form at least one non-photosensitive layer on the image forming layer. For example, a protective layer may be provided on the image forming layer for the purpose of protecting the image forming layer, and on the opposite side of the support to prevent sticking between the heat developing materials or in the heat developing material roll. Preferably, a coat layer is provided. As a binder used for these protective layer or back coat layer, a glass transition point is higher than that of the image forming layer, and abrasion or a polymer that hardly deforms, for example, cellulose acetate, a polymer such as cellulose acetate butyrate, is a polymer of the binder. Selected from among them.

For the purpose of gradation adjustment, two or more image forming layers may be provided on one side of the support or one or more layers may be provided on both sides of the support.

In the photothermographic material according to the present invention,
In order to control the amount or wavelength distribution of light transmitted through the image forming layer, it is preferable to form a filter layer on the same side as or opposite to the image forming layer, or to include a dye or pigment in the image forming layer.

The dyes used in the present invention include:
Known compounds that absorb light in various wavelength ranges according to the color sensitivity of the heat-developable material can be used.

For example, when the heat-developable material according to the present invention is used as an image recording material using infrared light, Japanese Patent Application No. 11-25 / 1999
Squarylium dyes having a thiopyrylium nucleus (herein referred to as thiopyrylium squarylium dyes) and squarylium dyes having a pyrylium nucleus (herein referred to as pyrylium squarylium dyes), as disclosed in US Pat. It is also preferable to use a thiopyrylium croconium dye similar to a squarylium dye or a pyrylium croconium dye.

The compound having a squarylium nucleus refers to 1-cyclobutene-2-hydroxy- in the molecular structure.
The compound having a 4-one and the compound having a croconium nucleus are compounds having 1-cyclopentene-2-hydroxy-4,5-dione in the molecular structure. Here, the hydroxy group may be dissociated. Hereinafter, in the present specification, these dyes are collectively referred to as a squarylium dye for convenience. The dye is disclosed in JP-A-8-201959.
The compounds of the above are also preferred.

The photothermographic material of the present invention is prepared by dissolving or dispersing the above-mentioned materials of the respective constituent layers in a solvent,
It is preferable that the coating liquid is formed by applying a plurality of these coating liquids simultaneously and then performing a heat treatment. Here, “multi-layer coating at the same time” means that a coating solution for each constituent layer (for example, a photosensitive layer and a protective layer) is prepared, and when the coating solution is applied to a support, coating and drying are repeated for each layer individually. In other words, it means that each constituent layer can be formed in a state where the steps of simultaneously performing the multilayer coating and drying can be performed at the same time. That is, the upper layer is provided before the remaining amount of the entire solvent in the lower layer becomes 70% by mass or less.

There is no particular limitation on the method of simultaneously applying a plurality of constituent layers in a multi-layered manner. For example, known methods such as a bar coater method, a curtain coat method, an immersion method, an air knife method, a hopper application method, and an extrusion application method. Can be used. Of these, a pre-metering type coating method called an extrusion coating method is more preferable. The extrusion coating method is suitable for precision coating and organic solvent coating since there is no volatilization on the slide surface unlike the slide coating method. This coating method has been described on the side having the photosensitive layer, but the same applies to the case where the backcoat layer is provided and the coating is performed together with the undercoating. Regarding the simultaneous multi-layer coating method for a heat developing material, see JP-A-20
No. 00-015173 has a detailed description.

In the present invention, it is preferable to select an appropriate amount of silver for application according to the purpose of the photothermographic material. However, for the purpose of medical images, 0.6 g / m ^2.
It is preferably at least 2.5 g / m ² . Furthermore, 0.8g
/ M ² or more and 1.5 g / m ² or less. Of the coated silver amount, those derived from silver halide account for 2% of the total silver amount.
% To 18%, more preferably 5% to 1%.
5% is preferred.

In the present invention, the coating density of silver halide grains having a particle size of 0.01 μm or more (equivalent sphere diameter) is 1%.
It is preferably from × 10 ¹⁴ / m ^{2 to} 1 × 10 ¹⁸ / m ² . Furthermore, 1 × 10 ¹⁵ pieces / m ² or more and 1 × 10 ¹⁷ pieces / m ² or more
The following is preferred.

The coating density of the non-photosensitive long-chain aliphatic carboxylic acid silver is 1 × 10 ⁻¹⁷ g or more per silver halide grain having a particle size of 0.01 μm or more (equivalent sphere equivalent particle size). × 10 ⁻¹⁵ g or less, further 1 × 10 ⁻¹⁶ g or more and 1 ×
It is preferably 10 ^-14 g or less.

When the coating is performed under the above-mentioned conditions, the maximum optical density of the silver image per a fixed amount of silver applied, that is, the silver coating amount (covering power), the color tone of the silver image, etc. Preferred results are obtained from a viewpoint.

In the present invention, the photothermographic material is an
5 to 1000 mg / m solvent during image formation ^TwoContained in the range
Is preferred. Preferably 100 to 500 mg /
m^TwoIt is necessary to adjust so that It
Photothermographic material with high sensitivity, low fog and high density
Becomes

As the solvent used in the present invention, acetone,
Ketones such as methyl ethyl ketone and isophorone; alcohols such as methyl alcohol, ethyl alcohol, i-propyl alcohol, cyclohexanol and benzyl alcohol; ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol;
Glycols such as hexylene glycol; ether alcohols such as ethylene glycol monomethyl ether and diethylene glycol monoethyl ether; ethers such as i-propyl ether; esters such as ethyl acetate and butyl acetate; methylene chloride, dichlorobenzene and the like. Chlorides; hydrocarbons and the like. Other examples include water, formamide, dimethylformamide, toluidine, tetrahydrofuran, acetic acid and the like. However, it is not limited to these. In addition, these solvents are used alone,
Alternatively, several types can be used in combination.

The content of the solvent in the photothermographic material can be adjusted by changing conditions such as temperature conditions in a drying step or the like after the coating step. The content of the solvent can be measured by gas chromatography under conditions suitable for detecting the contained solvent.

When the photothermographic material of the present invention is the invention of claim 7, a laser beam is generally used for recording an image. In the exposure of the photothermographic material of the invention, it is desirable to use a light source appropriate for the color sensitivity imparted to the material. For example, if the material can be sensed by infrared light, it can be applied to any light source in the infrared light range, but the laser power is high, and the photothermographic material is made transparent. From the viewpoint of being able to do so, an infrared semiconductor laser (780 nm, 820 nm) is more preferably used.

In the present invention, the exposure is preferably performed by laser scanning exposure, but various methods can be adopted as the exposure method. For example, as a first preferred method, there is a method using a laser scanning exposure machine in which an angle between an exposure surface of a photosensitive material and a scanning laser beam does not become substantially perpendicular.

Here, "not substantially vertical" means that the angle is most vertical during laser scanning, preferably 55 to 88 degrees, more preferably 60 to 86 degrees, and still more preferably. Means 65 ° to 84 °, most preferably 70 ° to 82 °.

The beam spot diameter on the exposed surface of the photosensitive material when the laser light is scanned on the photosensitive material is preferably 200 μm or less, more preferably 100 μm or less. It is preferable that the spot diameter is small in that the shift angle of the laser incident angle from the perpendicular can be reduced. Note that the lower limit of the beam spot diameter is 10 μm. By performing such laser scanning exposure, it is possible to reduce image quality deterioration related to reflected light such as occurrence of unevenness like interference fringes.

As a second method, it is preferable that the exposure in the present invention is performed using a laser scanning exposure machine that emits a scanning laser beam that is a vertical multi. Image quality deterioration such as generation of interference fringe-like unevenness is reduced as compared with the scanning laser beam in the longitudinal single mode.

[0308] In order to form the vertical multiple, a method such as combining, using return light, or superimposing a high frequency is preferable.
In addition, the vertical multi means that the exposure wavelength is not single, and the distribution of the exposure wavelength is usually 5 nm or more, preferably 10 nm or more.
nm or more. The upper limit of the exposure wavelength distribution is not particularly limited, but is usually about 60 nm.

Further, as a third mode, it is preferable to form an image by scanning exposure using two or more lasers.

An image recording method using such a plurality of lasers includes an image writing means of a laser printer or a digital copying machine for writing an image by a plurality of lines in one scan due to a demand for higher resolution and higher speed. This is a technique used and is known, for example, from JP-A-60-166916. This is a method of deflecting and scanning laser light emitted from a light source unit with a polygon mirror and forming an image on a photoreceptor via an fθ lens or the like. It is.

The image formation of the laser beam on the photoreceptor in the image writing means of the laser printer or the digital copier is performed from the image formation position of one laser beam for the purpose of writing an image by a plurality of lines in one scanning. The next laser light is imaged shifted by one line. Specifically, the two light beams are close to each other at an interval of several tens of μm on the image plane in the sub-scanning direction, and have a print density of 400 dpi (in the present invention, 1 inch or 2.54 cm per inch). The dot printing density is defined as dpi (dot per inch), and the pitch of the two beams in the sub-scanning direction is 6
3.5 μm, 42.3 μm at 600 dpi. In contrast to such a method in which the resolution is shifted in the sub-scanning direction, the present invention is characterized in that two or more lasers are focused on the exposure surface while changing the incident angle at the same location to form an image. In this case, one ordinary laser (wavelength λ [n
m]), the exposure energy on the exposed surface is E
When N lasers used for exposure have the same wavelength (wavelength λ [nm]) and the same exposure energy (En), 0.9 × E ≦ En × N ≦ 1.1 × E It is preferred to be within the range. By doing so, energy is secured on the exposed surface, but the reflection of each laser beam to the image forming layer is reduced because the exposure energy of the laser is low, and thus the generation of interference fringes is suppressed.

[0312] In the above description, the wavelength of the plurality of lasers is set to λ.
Although the same one is used, one having a different wavelength may be used. In this case, (λ−30) <for λ [nm]
λ1, λ2,... λn ≦ (λ + 30).

In the image recording methods of the first, second and third embodiments, the laser used for scanning exposure is generally well-known, such as ruby laser or YAG laser.
Lasers, solid state lasers such as glass lasers; gas lasers such as He-Ne laser, Ar ion laser, Kr ion laser, CO ₂ laser, CO laser, He-Cd laser, N ₂ laser, excimer laser; InGaP laser, Al
GaAs laser, GaAsP laser, InGaAs laser, InAsP laser, CdSnP ₂ laser, GaSb
A semiconductor laser such as a laser; a chemical laser, a dye laser, or the like can be selected and used as appropriate according to the intended use.
It is preferable to use a semiconductor laser of 0 to 1200 nm. In a laser used in a laser imager or a laser imagesetter, the beam spot diameter on the exposed surface of the material when scanning the heat developing material is generally 5 to 75 μm as a short axis diameter and as a long axis diameter. 5-100μ
m, and the scanning speed of the laser beam depends on the sensitivity and laser power at the laser oscillation wavelength inherent to the heat developing material.
An optimum value can be set for each photothermographic material.

The thermal development processing apparatus according to the present invention includes a film supply section represented by a film tray, a laser image recording section, and a thermal development section for supplying uniform and stable heat to the entire surface of the photothermographic material. And a transport unit from the film supply unit through laser recording until the photothermographic material on which an image has been formed by thermal development is discharged out of the apparatus. FIG. 1 shows a specific example of the thermal developing apparatus of this embodiment.

The heat developing apparatus 100 includes a feeding section 110 for feeding sheet-shaped heat-developable photosensitive materials (also referred to as photothermographic elements or simply films) one by one.
It has an exposure section 120 for exposing the fed film F, a developing section 130 for developing the exposed film F, a cooling section 150 for stopping the development, and an accumulation section 160, and supplies the film F from the feeding section. Roller pair 140 for feeding the film to the developing unit, a pair of feed rollers 144 for smoothly transporting the film F between the respective units.
It comprises a plurality of roller pairs such as 1, 142, 143, 145. The heat developing section is a heating means for developing the film F. The heat drum 1 having a plurality of opposed rollers 2 which can be heated while being held almost in close contact with the outer periphery, and the peeling for peeling the developed film F and sending it to the cooling section. It consists of nails 6 and the like.

If the heat development processing apparatus has been used for a long time,
The photothermographic material is conveyed to a place where the surface of the conveying roller or the heat developing section is worn away and roughened, dust or the like is mixed in from the outside, and minute projections are formed on the surface. The minute projections here are, specifically, somewhere along the entire path in which the photothermographic material is conveyed in the photothermographic processing apparatus, perpendicular to the conveying direction, on the surface where the photothermographic material is in contact, and on a roller or the like. At least one per side length of a heat-developable photosensitive material, the height of which is 10 μm or more.
Appears as 150 μm. The position of the protrusion has the greatest effect when the surface temperature of the photothermographic material after the heat development is in a range from the heat development temperature to the heat development temperature minus 40 ° C. In general, if the height of the projection is smaller than 10 μm, no scratch is generated, but if the height is larger than this, a scratch is generated and an image defect occurs after development. In the case of the photothermographic material of the present invention, these minute Even if there is a projection, no scratch occurs,
No defects occur in the image. If the height is larger than 150 μm, the conveyance of the photothermographic material itself will be damaged.

The speed of transport of the photothermographic material was 10 m.
m / sec to 500 mm / sec is a preferable range.

The development conditions of the heat-developable material of the present invention vary depending on the equipment, apparatus, or means used, but typically, the heat-developable material is exposed imagewise at a suitable high temperature. In this way, development is performed. The latent image obtained after the exposure has a moderate high temperature (about 80 to 200 ° C.,
The development is carried out by heating the heat-developable material at a temperature of preferably about 100 to 200 ° C. for a sufficient time (generally about 1 second to about 2 minutes).

If the heating temperature is lower than 80 ° C., a sufficient image density cannot be obtained in a short time. If the heating temperature is higher than 200 ° C., the binder is melted, and not only the image itself, such as transfer to a roller, but also the transportability and the like. It also has an adverse effect on developing machines. By heating, a silver image is generated by an oxidation-reduction reaction between an organic silver salt (functioning as an oxidizing agent) and a reducing agent. This reaction process proceeds without any supply of a processing liquid such as water from the outside.

As the apparatus, apparatus or means for heating, for example, a typical heating means such as a hot plate, an iron, a hot roller, a heat generator using carbon or white titanium or the like may be used. More preferably, the heat-developable material provided with the protective layer may be subjected to heat treatment by bringing the surface having the protective layer into contact with a heating means, in order to perform uniform heating, and to improve heat efficiency and workability. Preferred from a viewpoint,
It is preferable that the surface having the protective layer is conveyed while being in contact with a heat roller, heated, and developed.

[0321]

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

Example 1 [Preparation of Subbed Photographic Support] A commercially available biaxially stretched, heat-fixed, 175 μm thick, optical density 0.170 (measured with a Konica Corporation densitometer PDA-65). 8W / on both sides of PET film colored blue with blue dye
m ² · m of corona discharge treatment, the following undercoating coating liquid a-1 is applied to one side to a dry film thickness of 0.8 μm, and dried to form an undercoating layer A-1, and vice versa. On the side surface, the following undercoating coating solution b-1 was applied so as to have a dry film thickness of 0.8 μm, and dried to obtain an undercoating layer B-1.

[0323]

Embedded image

<< Undercoating Coating Solution a-1 >> Butyl Acrylate (30% by Mass) T-Butyl Acrylate (20% by Mass) Styrene (25% by Mass) 2-Hydroxyethyl Acrylate (25% by Mass) Copolymer Latex Solution (Solid content: 30%) 270 g C-1 0.6 g hexamethylene-1,6-bis (ethylene urea) 0.8 g Finish to 1 liter with water << Subtraction coating solution b-1 >> Butyl acrylate (40% by mass) Styrene (20% by mass) Copolymer latex liquid of glycidyl acrylate (40% by mass) (solid content: 30%) 270 g C-1 0.6 g Hexamethylene-1,6-bis (ethylene urea) 0.8 g To 1 liter with water Finishing Next, on the upper surface of the undercoat layer A-1 and the undercoat layer B-1,
A corona discharge of 8 W / m ² · min. Was performed, and the following lower coating liquid a-2 was coated on the lower coating layer A-1 with a dry film thickness of 0.1 μm.
The undercoating layer A-2 is coated with the following undercoating layer coating solution b-2 on the undercoating layer B-1 so as to have a dry film thickness of 0.4 μm. Coated as B-2.

<< Coating Solution for Subbing Upper Layer a-2 >> Gelatin to be 0.4 g / m ² Mass C-1 0.2 g C-2 0.2 g C-3 0.1 g Silica particles (average particle size 3 μm) 0 1 g Finished to 1 liter with water << Coating solution b-2 for lower undercoat >> Sb-doped SnO ₂ (SNS10M; manufactured by Ishihara Sangyo Co., Ltd.) 60 g Latex solution containing C-4 as a component (solid content 20%) 80 g Ammonium sulfate 0.5 g C-5 12 g Polyethylene glycol (weight average molecular weight 600) 6 g Finished to 1 liter with water

[0326]

Embedded image

[0327]

Embedded image

<< Back side coating >> While stirring 830 g of methyl ethyl ketone (MEK), cellulose acetate butyrate (Eastman Chemical Company,
CAB381-20) 84.2 g and polyester resin (Bostic, Vitel PE2200B) 4.
5 g was added and dissolved. Next, 0.30 g was added to the dissolved liquid.
F-activator (Asahi Glass Co., Ltd., Surflon KH40) dissolved in 43.2 g of methanol
4.5 g and 2.3 g of an F-based activator (Dainippon Ink Co., Ltd., Megafag F120K) were added, and sufficiently stirred until dissolved. Finally, 1% by mass in methyl ethyl ketone
75 g of silica (WR Grace, Syloid 64X6000) dispersed by a dissolver-type homogenizer at a concentration of 75 g was added and stirred to prepare a coating solution for the back surface side.

[0329]

Embedded image

The back surface coating solution thus prepared was
Coating was performed with an extrusion coater at a coating speed of 50 m / min so that the dry film thickness became 3.5 μm. The drying was performed for 5 minutes using a drying air having a drying temperature of 100 ° C and an outdoor temperature of 10 ° C.

<< Preparation of Photosensitive Silver Halide Emulsion A >> A1 Phenylcarbamoylated gelatin 88.3 g Compound (A) (10% aqueous methanol solution) 10 ml Potassium bromide 0.32 g Finish up to 5429 ml with water B1 0.67 mol / L Silver nitrate aqueous solution 2635 ml C1 Potassium bromide 51.55 g Potassium iodide 1.47 g Finish up to 660 ml with water D1 Potassium bromide 154.9 g Potassium iodide 4.41 g Iridium chloride (1% solution) 0.93 ml Finish up to 1982 ml with water E1 0.4 mol / L aqueous potassium bromide solution Silver potential control amount below F1 Potassium hydroxide 0.71 g Finish to 20 ml with water G1 56% acetic acid aqueous solution 18.0 ml H1 1.72 g anhydrous sodium carbonate Finish to 151 ml with water Compound (A) : HO (CH ₂ C _{2 O) n - (CH (} CH 3) CH 2 O) 17
_{- (CH 2 CH 2 O)} m H (m + n = 5~7) Japanese Patent Publication No. 58-58288, a solution (A1) with a mixing and stirring machine shown in Nos. 58-58289 solution (B1)
を amount and the whole amount of the solution (C1)
While controlling the temperature to 8.09, the mixture was added by the simultaneous mixing method in 4 minutes and 45 seconds to form nuclei. One minute later, the solution (F1)
Was added. During this time, pAg was appropriately adjusted using (E1). After 6 minutes, 3/4 of the solution (B1)
The amount and the total amount of the solution (D1) were measured at a temperature of 45 ° C. and pAg8.
While controlling to 09, the mixture was added over 14 minutes and 15 seconds by the double jet method. After stirring for 5 minutes, the temperature was lowered to 40 ° C., and the whole amount of the solution (G1) was added to precipitate a silver halide emulsion. The supernatant was removed, leaving 2000 ml of the sedimented portion, 10 liters of water was added, and after stirring, the silver halide emulsion was sedimented again. The supernatant was removed, leaving 1500 ml of sedimentation, 10 liters of water was added, and after stirring,
The silver halide emulsion was allowed to settle. Settling portion 1500ml
After removing the supernatant, the solution (H1) was added, the temperature was raised to 60 ° C., and the mixture was further stirred for 120 minutes. Finally p
H was adjusted to 5.8, and 11 per mole of silver
Water was added so as to be 61 g to obtain a photosensitive silver halide emulsion A.

This emulsion had an average grain size of 0.058 μm.
m, coefficient of variation of particle size 12%, [100] face ratio 9
It was 2% monodispersed cubic silver iodobromide grains.

<< Preparation of Powdered Organic Silver Salt A >> 130.8 g of behenic acid and 67.7 g of arachidic acid in 4720 ml of pure water.
g, 43.6 g of stearic acid and 2.3 g of palmitic acid were dissolved at 80 ° C. Next, 540.2 ml of a 1.5 M aqueous sodium hydroxide solution was added, 6.9 ml of concentrated nitric acid was added, and the mixture was cooled to 55 ° C. to obtain a fatty acid sodium solution. While maintaining the temperature of the above fatty acid sodium solution at 55 ° C., 45.3 g of the above-mentioned photosensitive silver halide emulsion A and 450 ml of pure water were added and stirred for 5 minutes.

Next, 702.6 ml of a 1M silver nitrate solution was added to 2
And the mixture was stirred for 10 minutes to obtain an organic silver salt dispersion. Thereafter, the obtained organic silver salt dispersion was transferred to a water washing container, deionized water was added thereto, and the mixture was stirred and allowed to stand. Then, the organic silver salt dispersion was floated and separated to remove lower water-soluble salts. After that, washing with deionized water and draining are repeated until the conductivity of the waste water reaches 2 μS / cm, and centrifugal dehydration is performed. Seisin Company)
Was dried under a nitrogen gas atmosphere and operating conditions of hot air temperature at the entrance of the dryer until the water content became 0.1% to obtain a dried organic silver salt A of an organic silver salt.

The moisture content of the organic silver salt composition was measured using an infrared moisture meter. << Preparation of Preliminary Dispersion A >> 14.57 g of a binder powder serving as an image forming layer binder described in Table 2 was dissolved in 1457 g of methyl ethyl ketone, and the powdered organic silver salt was stirred with a dissolver DISPERMAT CA-40M manufactured by VMA-GETZMANN. A preliminary dispersion A was prepared by gradually adding 500 g of A and mixing well.

<< Preparation of Photosensitive Emulsion Dispersion 1 >> Zirconia beads having a diameter of 0.5 mm (Toray Toraycere, manufactured by Toray Industries Co., Ltd.) were prepared using Preparative Dispersion A using a pump such that the residence time in the mill was 1.5 minutes. Type disperser D filled with 80% of the product
ISPERMAT SL-C12EX type (VMA-GE
TZMANN Co., Ltd.) and dispersed at a mill peripheral speed of 8 m / s to prepare a photosensitive emulsion dispersion liquid 1.

<< Preparation of Stabilizer Liquid >> 1.0 g of stabilizer 1,
0.31 g of potassium acetate was dissolved in 4.97 g of methanol to prepare a stabilizer solution.

<< Preparation of Infrared Sensitizing Dye Liquid A >> 19.2 mg
Sensitizing dye, 1.488 g of 2-chloro-benzoic acid, 2.779 g of stabilizer 2 and 365 mg of 5-methyl-2-mercaptobenzimidazole in 31.3 m.
1 liter of MEK in the dark to prepare an infrared sensitizing dye solution A.

<< Preparation of Additive Solution a >> 1,1 as a developer
-Bis (2-hydroxy-3,5-dimethylphenyl)
27.98 g of 2-methylpropane and 1.54 g of 4
-Methylphthalic acid, 0.48 g of the infrared dye 1
Dissolved in 110 g of K to obtain an additive liquid a.

<< Preparation of Additive Solution b >> 1.56 g of the antifoggant 2, 3.43 g of phthalazine were dissolved in 40.9 g of MEK to prepare an additive solution b.

[0341]

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<< Preparation of Coating Solution for Image Forming Layer >> In an inert gas atmosphere (nitrogen: 97%), the above-mentioned photosensitive emulsion dispersion liquid 1 (50 g) and 15.11 g of MEK were kept at 21 ° C. with stirring to increase the temperature. 1000 μl of Sensitizer S-5 (0.5% methanol solution) was added, and 2 minutes later, antifoggant 1
390 μl (10% methanol solution) was added, and the mixture was stirred for 1 hour. Further, 494 μl of calcium bromide (10% methanol solution) was added, and the mixture was stirred for 10 minutes. Then, a gold sensitizer Au-5 corresponding to 1/20 mol of the organic chemical sensitizer was added, and the mixture was further stirred for 20 minutes. . Subsequently, the stabilizer liquid 167
Then, 1.32 g of the infrared sensitizing dye solution was added, and the mixture was stirred for 1 hour. Thereafter, the temperature was lowered to 13 ° C., and the mixture was further stirred for 30 minutes. 13 ℃
While keeping the temperature at 13.2 g, 13.31 g of the binder shown in Table 2 was added, and the mixture was stirred for 30 minutes. Then, 1.084 g of tetrachlorophthalic acid (9.4 mass% MEK solution) was added, and
Stir for 5 minutes. While continuing stirring, 12.43
g of additive solution a, 1.6 ml of Desmodur N330
0 / Mobay's aliphatic isocyanate (10% M
EK solution), and 4.27 g of the additive solution b was sequentially added and stirred to obtain an image forming layer coating solution.

[0343]

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<< Preparation of Matting Agent Dispersion >> Cellulose acetate butyrate (Eastman Chemical)
Co., Ltd., 7.5 g of CAB171-15)
g, and silica (WR Grace)
5 g of Syloid 64X6000) was added and dispersed by a dissolver-type homogenizer at 8000 rpm for 30 minutes to prepare a matting agent dispersion.

<< Preparation of Coating Solution for Surface Protective Layer >> While 865 g of MEK (methyl ethyl ketone) was stirred, cellulose acetate butyrate (Eastman Chemical) was used.
al., CAB171-15) and an organosilica sol MIBK-ST (manufactured by Nissan Chemical Industries, Ltd.) in a total amount of 96 so that the organosilica sol has the mass ratio (%) shown in Table 2.
g, 4.5 g of polymethyl methacrylic acid (Rohm & Haas Co., Ltd., Paraloid A-21), 1.5 g of vinylsulfone compound (VSC), and 1.0 g of benzotriazole.
g, F-based activator (Asahi Glass Co., Ltd., Surflon KH40) 1.0 g was added and dissolved. Next, the above matting agent dispersion 3
0 g was added and stirred to prepare a surface protective layer coating solution.

[0346]

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<< Coating on the Image Forming Layer Surface Side >> The coating materials for the image forming layer and the coating solution for the surface protective layer are simultaneously layer-coated with an extruder (extrusion) coater at a coating speed of 50 m / min. Was prepared. The coating was performed such that the photosensitive layer had a coated silver amount of 1.9 g / m ² and the surface protective layer had a dry film thickness of 2.5 μm. Thereafter, drying was performed for 10 minutes using a drying air having a drying temperature of 75 ° C. and a dew point temperature of 10 ° C.

<< Measurement of Plastic Deformation Rate >> A sample having a size of 2 cm square was cut out from the photothermographic material prepared as described above, and was adhered to the entire surface of a 1 mm-thick slide glass plate with as little as possible an instant adhesive. Surface evaluation system equipped with a heating stage (manufactured by Akashi (M
It was measured in the following manner using ZT-3)).

A triangular pyramid indenter (having a plane angle of 68 degrees) was pressed into a sample having a surface temperature of 25 ° C. until a load of 9.8 mN was reached.
After holding for 0 seconds to alleviate creep, the load was released. The amount of indentation deformation when the load is released is defined as the total deformation (elastic deformation + plastic deformation), and the part that did not return to the original position before the load was applied even after the load was released is defined as the plastic deformation. The plastic deformation rate was calculated by the following equation (1). (Condition 1) Plastic deformation rate (%) = Plastic deformation amount / (Elastic deformation amount + Plastic deformation amount) × 100 (1) The same evaluation was performed at a surface temperature of 100 ° C. and a load of 1.96 mN. (Condition 2) << Evaluation of streak-like or spot-like scratches >> After processing the photothermographic material prepared as described above into a half-cut size (14 × 17 inches), the photothermographic processing apparatus shown in FIG. Processed in the manner described above. The photothermographic material is taken out of the film tray, transported to the laser exposure section, and then imaged from the image forming layer surface side by an exposure machine using a semiconductor laser having a wavelength of 800 nm to 820 nm as a multi-mode semiconductor laser as an exposure source. Exposure by laser scanning was performed at an exposure amount at which the density was 3.0. At this time, an image was formed at an angle of 75 degrees between the exposure surface of the photosensitive material and the exposure laser beam.

Thereafter, the photothermographic material is conveyed to a photothermographic development unit, and the heat drum is brought into contact with the protective layer on the image forming layer side of the photothermographic material at 125 ° C.
After 15 seconds of heat development, the photothermographic material was carried out of the apparatus. At this time, the transport speed other than the heat developing section and the laser exposure section was 200 mm / sec. At this time, the minute projections were provided on a part of the pair of transport rollers 141 and 145 of the transport roller of the thermal developing apparatus. As the minute projections, a 5-mm square size 133 μm thick scotch tape was used, and the corner portions were adhered so as to be perpendicular to the transport direction of the thermal development transport material. At this time, the nip pressure of the roller pair was set to 9.8 × 10 ⁻² N / cm. Exposure and development were performed in a room conditioned at 23 ° C. and 50% RH.

Under the above conditions, the sample was 100
Processed. The developed sample thus obtained was visually evaluated and ranked according to the following criteria. Here, the occurrence frequency indicates the ratio of the number of stripes or spot-like scratches in the total number of processed sheets.

Rank Evaluation criteria 5: Occurrence frequency 0% That is, no occurrence 4: Occurrence frequency 1-2% However, the appearance of scratches is very weak 3: Occurrence frequency 3-5% The appearance of scratches is weak 2: Occurrence frequency 6-9% The appearance of scratches is weak 1: Occurrence frequency 10% or more

<< Measurement of Solvent Content in Film >> A film area of 46.3 cm ² was cut out and cut into 5 mm.
It was finely chopped, stored in a dedicated vial, sealed with a septum and an aluminum cap, and set in a Hewlett-Packard HP7694 headspace sampler.

For gas chromatography (GC) connected to a head space sampler, a type 5971 manufactured by Hewlett-Packard Company equipped with a flame ionization detector (FID) was used as a detector. The main measurement conditions are as follows.

Headspace Sampler Heating Condition: 12
0 ° C, 20 minutes GC introduction temperature: 150 ° C Column: DB-624 manufactured by J & W Increasing temperature: 45 ° C, holding for 3 minutes → 100 ° C (8 ° C / min) A gas chromatogram was obtained using the above measurement conditions. The solvent to be measured was MEK and methanol, and a predetermined amount diluted with each of butanol in the solvent on the left was stored in a dedicated vial, and then prepared using the peak area of the chromatogram obtained by measuring in the same manner as above. The calibration curve was used to obtain the solvent content in the film samples.

The photosensitive materials 101 and 102 produced had a solvent content of 55 mg / m ² (101) and 32 mg / m ² (1
02), the effect on the characteristics of the photothermographic material during development was substantially the same, and the effect on photographic performance was not substantially different.

[0357]

[Table 2]

From Table 2, it is clear that the light-sensitive material of the present invention is a heat-developable light-sensitive material having less streak-like or spot-like scratches than the comparative light-sensitive material.

Example 2 << Coating on Back Side >> (Coating Liquid for Backing Upper Antistatic Layer) While stirring 208 g of methyl ethyl ketone (MEK), cellulose acetate butyrate (Eastman Chemical) was used.
And CAB381-20) and SNS10M (manufactured by Ishihara Sangyo Co., Ltd.), which is SnO ₂ doped with Sb as a conductive metal oxide, in a mass ratio of 65/35 and a total amount of 21.1.
g and polyester resin (Bostic, Vite
1.1 g of 1PE2200B) was added and dissolved. Next, 4.5 g of an F-based activator (Asahi Glass Co., Surflon KH40) and 1.8 g of an F-based activator (Dainippon Ink Co., Ltd., MegaFag F120K) dissolved in 43.2 g of methanol were added, and the mixture was sufficiently dissolved. Was stirred. Finally, silica dispersed in methyl ethyl ketone at a concentration of 1% by mass with a dissolver-type homogenizer (WR Grace Co., Ltd.)
(Syloid 64X6000) was added and stirred to prepare a coating solution for the backing upper antistatic layer.

(Backing Lower Layer Coating Solution) While stirring 623 g of methyl ethyl ketone (MEK), cellulose acetate butyrate (Eastman Chemical) was used.
Co., Ltd., CAB381-20) 63.2 g and polyester resin (Bostic, VitelPE2200B)
3.8 g was added and dissolved. Next, in the dissolved solution,
0.30 g of the infrared dye 1 used in Example 1 was added, and further 0.5 g of an F-based activator (Dainippon Ink, Megafag F120K) dissolved in 25.9 g of methanol was added until dissolution. The mixture was sufficiently stirred. Finally, 15 g of silica (WR Grace, Syloid 64X6000) dispersed in methyl ethyl ketone at a concentration of 1% by mass with a dissolver-type homogenizer was added and stirred to prepare a backing lower layer coating solution.

The backing lower layer coating solution and the backing upper layer antistatic layer coating solution thus prepared were extruded using a coater such that the dry film thickness was 2.7 μm for the lower layer and 0.8 μm for the upper layer. Overcoating was performed simultaneously on the prepared subbed support at a coating speed of 50 m / min in this order. Drying was performed at a drying temperature of 100 ° C and an outdoor temperature of 10 ° C.
It dried for 5 minutes using the drying wind of ° C.

A photosensitive emulsion dispersion 1, a stabilizer solution, an infrared sensitizing dye solution A, an additive solution a and an additive solution b, and an additive solution c prepared in the same manner as in Example 1 were prepared as follows. However, the binder of the preliminary dispersion A is the binder P-7.
Was used.

<< Preparation of Additive Solution c >> 5.0 g of silver saving agent X
Was dissolved in 45.0 g of MEK to obtain an additive liquid c.

[0364]

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<< Preparation of Image Forming Layer Coating Solution A >> In an inert gas atmosphere (nitrogen: 97%), the photosensitive emulsion dispersion liquid 1 (50 g) and MEK 15.11 g were kept at 21 ° C. with stirring to obtain a chemical solution. 1000 μl of sensitizer S-5 (0.5% methanol solution) was added, and 2 minutes later, 390 μl of antifoggant 1 (10% methanol solution) was added, followed by stirring for 1 hour. Further, 494 μl of calcium bromide (10% methanol solution) was added, and the mixture was stirred for 10 minutes. Then, a gold sensitizer Au-5 corresponding to 1/20 mol of the organic chemical sensitizer was added, and the mixture was further stirred for 20 minutes. . Subsequently, the stabilizer liquid 167
Then, 1.32 g of the infrared sensitizing dye solution was added, and the mixture was stirred for 1 hour. Thereafter, the temperature was lowered to 13 ° C., and the mixture was further stirred for 30 minutes. 13 ℃
While keeping the temperature at 13.3, the binder P-7 of the present invention was added in 13.3.
After adding 1 g and stirring for 30 minutes, 1.084 g of tetrachlorophthalic acid (9.4 mass% MEK solution) was added and 1
Stir for 5 minutes. While continuing stirring, 12.43
g of additive solution a, 1.6 ml of Desmodur N330
0 / Mobay's aliphatic isocyanate (10% M
EK solution), and 4.27 g of additive solution b was sequentially added and stirred to obtain image forming layer coating solution A.

<< Preparation of Coating Solution B for Image Forming Layer >> In an inert gas atmosphere (nitrogen: 97%), the above-mentioned photosensitive emulsion dispersion liquid 1 (50 g) and 15.11 g of MEK were kept at 21 ° C. while stirring to obtain a chemical solution. 1000 μl of sensitizer S-5 (0.5% methanol solution) was added, and 2 minutes later, 390 μl of antifoggant 1 (10% methanol solution) was added, followed by stirring for 1 hour. Further, 494 μl of calcium bromide (10% methanol solution) was added, and the mixture was stirred for 10 minutes. Then, a gold sensitizer Au-5 corresponding to 1/20 mol of the organic chemical sensitizer was added, and the mixture was further stirred for 20 minutes. . Subsequently, the stabilizer liquid 167
Then, 1.32 g of the infrared sensitizing dye solution was added, and the mixture was stirred for 1 hour. Thereafter, the temperature was lowered to 13 ° C., and the mixture was further stirred for 30 minutes. 13 ℃
While keeping the temperature at 13.3, the binder P-5 of the present invention was added in 13.3.
After adding 1 g and stirring for 30 minutes, 1.084 g of tetrachlorophthalic acid (9.4 mass% MEK solution) was added and 1
Stir for 5 minutes. While continuing stirring, 12.43
g of additive solution a, 1.6 ml of Desmodur N330
0 / Mobay's aliphatic isocyanate (10% M
EK solution), 4.27 g of additive solution b and 10.0 g of additive solution c were sequentially added and stirred to obtain an image forming layer coating solution B.

<< Preparation of Coating Solution for Surface Protection Layer >> While 865 g of MEK (methyl ethyl ketone) was stirred, cellulose acetate butyrate (Eastman Chemical) was used.
al, CAB171-15), 96 g, polymethylmethacrylic acid (Rohm & Haas, Paraloid A-21)
4.5 g, and 1.5 g of a vinyl sulfone compound (VSC).
g, benzotriazole (1.0 g) and an F-based activator (Asahi Glass Co., Ltd., Surflon KH40) (1.0 g) were added and dissolved. Next, 30 g of the matting agent dispersion used in Example 1 was added and stirred to prepare a surface protective layer coating solution.

The coating solution for the image forming layer and the coating solution for the surface protective layer were extruded (extrusion) using a coater to coat a total of three layers of two image forming layers and one protective layer at a coating speed of 50%.
m / min to form a photosensitive material 2
01 was produced. In the coating, the image forming layer A had a coating amount of silver of 0.1.
7 g / m ² , the image-forming layer B was coated with 0.3 g / m ^{2 of} silver, and the surface protective layer was dried so as to have a dry film thickness of 2.5 μm. Thereafter, drying was performed for 10 minutes using a drying air having a drying temperature of 50 ° C and a dew point temperature of 10 ° C.

<< Measurement of Plastic Deformation Rate >> When the plastic deformation rate of the obtained photothermographic material 201 was measured in exactly the same manner as in Example 1, it was 39% under Condition 1 and 45% under Condition 2.

<Evaluation of streak-like or spot-like scratches> The prepared photothermographic material was processed into a half-cut size (14 × 17 inches), and then processed using the photothermographic processing apparatus shown in FIG. 1 in the following manner. . After taking out the photothermographic material from the film tray and transporting it to the laser exposure unit, the image density was measured from the image forming layer surface side with an exposure machine using a single mode semiconductor laser having a wavelength of 800 nm to 820 nm as an exposure source under the conditions shown in Table 3. Exposure by laser scanning was given at an exposure amount that resulted in 1.0. At this time, an image was formed at an angle of 85 degrees between the exposure surface of the photosensitive material and the exposure laser beam.

Thereafter, the transfer and thermal development were performed in exactly the same manner as in Example 1, and the evaluation was performed.

[0372]

[Table 3]

As is clear from Table 3, it was found that the streak-like or spot-like flaws of the photographic material of the present invention were further improved by using two or more lasers.

Example 3 << Preparation of Organic Silver Salt Dispersion >> 7 g of stearic acid, 4 g of arachidic acid, 36 g of behenic acid and 850 ml of distilled water were heated at 90 ° C.
1 mol / liter NaOH with vigorous stirring
187 ml of an aqueous solution was added, and reacted for 120 minutes.
After adding 71 ml of a liter concentration of nitric acid, the temperature was lowered to 50 ° C. Then, with vigorous stirring, 21 g of silver nitrate
Was added over 100 seconds, and the mixture was allowed to stand for 20 minutes. Thereafter, the solid content was separated by suction filtration, and the solid content was washed with water until the conductivity of the filtrate became 30 μS / cm. 100 g of a 10% by mass aqueous solution of PVA 205 (polyvinyl alcohol manufactured by Kuraray Co., Ltd.) was added to the solid content thus obtained, and water was further added so as to have a total mass of 270 g. A silver salt crude dispersion was obtained.

This organic silver salt crude dispersion was subjected to collision pressure 98.07 MPa using a Nanomizer (manufactured by Nanomizer Co., Ltd.).
To obtain an organic silver salt dispersion. Organic silver salt particles contained in the obtained organic silver salt dispersion had an average minor axis of 0.04 μm,
Needle-shaped particles having an average major axis of 0.8 μm and a variation coefficient of 30%.

<< Preparation of Reducing Agent Dispersion >> 1,1-bis (2
-Hydroxy-3,5-dimethylphenyl) -3,5
To 100 g of 5-trimethylhexane (reducing agent) and 50 g of hydroxypropylcellulose, 850 g of water was added 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 (（G sand grinder mill:
The mixture was dispersed for 5 hours using IMEX Co., Ltd. to obtain a reducing agent dispersion.

<< Preparation of Organic Polyhalide Dispersion >> Water (940 g) was added to 50 g (0.127 mol) of tribromomethylphenylsulfone and 10 g of hydroxypropylcellulose.
g was added and mixed well to obtain a slurry. Mean diameter 0.
840 g of 5 mm zirconia beads were prepared, placed in a vessel together with the slurry, and dispersed with a disperser (1 / 4G sand grinder mill: manufactured by IMEX Co., Ltd.) for 5 hours to obtain an organic polyhalide dispersion.

<< Preparation of Photosensitive Silver Halide Emulsion >> Water 10
After dissolving 22 g of phthalated gelatin and 30 mg of potassium bromide in 00 ml and adjusting the pH to 5.0 at a temperature of 35 ° C., 18.6 g of silver nitrate and 0.
159 ml of an aqueous solution containing 9 g and 159 ml of an aqueous solution containing potassium bromide and potassium iodide in a molar ratio of 92: 8 were added over 10 minutes by a control double jet method while keeping the pAg at 7.7. Then 55.4 silver nitrate
476 ml of an aqueous solution containing g and 2 g of ammonium nitrate
And an aqueous solution containing 10 μmol / l of dipotassium hexachloridate and 1 mol / l of potassium bromide at a pAg of 7.7 was added over 30 minutes by a control double jet method, followed by 4-hydroxy-6-
Methyl-1,3,3a, 7-tetrazaindene (1 g) was added, and the pH was further lowered to cause coagulation and sedimentation for desalination. Thereafter, 0.1 g of phenoxyethanol was added and p
H5.9, pAg8.2, and silver iodobromide grains (iodine content core 8 mol%, average 2 mol%, average size 0.05
μm, projection area variation coefficient 8%, (100) plane ratio 85%
Of cubic particles) was completed.

The silver halide grains thus obtained were heated to 60 ° C., and 85 μmol of sodium thiosulfate and 11 μmol of 2,3,4,5,6-pentafluorophenyldiphenylphosphine selenide, and Mole of tellurium compound, 3 μmol of chloroauric acid, 270 μ of thiocyanic acid
After aging for 120 minutes, the mixture was rapidly cooled to 40 ° C., and then 100 μmol of a sensitizing dye was added. After stirring for 30 minutes, the mixture was rapidly cooled to 30 ° C. to obtain a silver halide emulsion 1. The above-mentioned temperature of 30 ° C. is used as the preparation temperature of silver halide emulsion 1.

[0380]

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<< Preparation of Image Forming Layer Coating Solution >> 1350 g of an organic silver salt dispersion and a 20% by weight aqueous solution 140 of PVA205 140
Then, 37 ml of a 10% by mass aqueous solution of phthalazine, 220 g of a reducing agent dispersion, and 61 g of the above organic polyhalide dispersion were added.
R3307B (manufactured by Dainippon Ink and Chemicals, Inc .; SBR containing styrene and butadiene as main copolymerization components)
Latex; average particle size of dispersed particles 0.1 to 0.15μ
m, 25 ° C., and 60% RH) (1100 g of the polymer equilibrium water content under the conditions of 60% RH), and then 120 g of the silver halide emulsion 1 was mixed to prepare a coating solution for the image forming layer. The pH of the solution was adjusted to 5.0 using 11 mol / l sulfuric acid.

<< Preparation of Coating Solution for Intermediate Layer >> 100 g of MP203 (modified polyvinyl alcohol manufactured by Kuraray Co., Ltd.) was dissolved in 900 ml of water, and di (2-sulfosuccinate)
2 ml of a 5% by weight aqueous solution of the sodium salt of ethylhexyl) ester were added.

<< Preparation of Coating Solution for Protective Layer >> In a solution of 145 g of inert gelatin in 1110 ml of warm water, 20
400 g of a mass% polyethyl acrylate latex,
57 mol of 1 mol / l sulfuric acid, di-sulfosuccinic acid (2
10 ml of a 5% by weight aqueous solution of -ethylhexyl) ester sodium salt and a 10% by weight methanol solution of phthalic acid 2
80 ml was added to obtain a protective layer coating solution.

<< Preparation of Coating Solution for Overcoat Layer >> Inert gelatin and colloidal inorganic fine particles (Snowtex C: manufactured by Nissan Chemical Industries, Ltd.) were prepared so that the inorganic fine particles had the mass ratio (%) shown in Table 4. A total of 129 g was dissolved by adding warm water to make a total of 1779 g, and a gelatin dispersion containing 12% by mass of polymethyl methacrylate fine particles (average particle size: 2.5 μm) was added.
30 g, 1 mol / l sulfuric acid 65 ml, sodium sulfosuccinate di (2-ethylhexyl) ester 5
The overcoat layer coating solution was continuously applied so that the flow ratio of potassium chromium (III) sulfate 12 hydrate to 2% by weight aqueous solution (hardening agent) was 0.3 with respect to Liquid 1 to which 20% by mass aqueous solution was added. Prepared.

<< Preparation of Coating Solution for Back Layer >> N, N ', N ", N" -tetraethylguanidine which is a solid base and 4-
Carboxylsulfonyl-phenylsulfone molar ratio 1:
10 g of polyvinyl alcohol 10 g, water 88 g
And a 1/16 g sand grinder mill (manufactured by Imex Co., Ltd.) to obtain a base solution. Basic dye precursor 2.1 g, acidic substance 7.9 g, 0.1 g (1.990 ×
10 ^-4 mol) antihalation dyes -1, organic solvent phase was mixed and dissolved in ethyl acetate 10g was mixed with the aqueous phase of polyvinyl alcohol 10g and water 80 g, to obtain a normal temperature by emulsion dispersed dyestuff (average particle Diameter 2.5 μm).
39 g of the base solution thus obtained, 26 g of the dye solution, and 36 g of a 10% by mass aqueous solution of polyvinyl alcohol were mixed to obtain a back layer coating solution.

[0386]

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<< Coating Solution for Back Layer Protective Layer >> Gelatin and SNS10M (manufactured by Ishihara Sangyo Co., Ltd.), which is SnO ₂ doped with Sb as the conductive metal oxide, are represented by Table 4 in terms of mass ratio of the conductive metal oxide. (%), Total amount 20 g, polymethyl methacrylate (average particle size 7 μm)
0.6 g, sodium dodecylbenzenesulfonate 0.
4 g and 1 g of X-22-2809 (silicone compound manufactured by Shin-Etsu Silicone Co., Ltd.) were dissolved in 480 g of water to obtain a back layer protective layer coating solution.

<< Preparation of Undercoat Coating Liquid A >> Polyester copolymer dispersion Pesresin A-515GB (30%, manufactured by Takamatsu Oil & Fat Co., Ltd.) in 200 ml, 50 g of polystyrene fine particles (average particle size: 0.2 μm), surfactant A (1% by mass) 2
0 ml was added, and distilled water was added thereto to make 1000 ml.

[0389]

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<< Preparation of Undercoat Coating Solution B >> 680 m of distilled water
200 ml of an aqueous dispersion of a styrene-butadiene copolymer (styrene / butadiene / itaconic acid = 47/50/3 (mass ratio), concentration 30% by mass) and 0.1 g of polystyrene fine particles (average particle size 2.5 μm). The mixture was further added, and distilled water was further added to make 1000 ml, thereby obtaining an undercoating coating solution B.

<< Preparation of Undercoat Coating Solution C >> 10 g of inert gelatin was dissolved in 500 ml of distilled water.
40 g of an aqueous dispersion (40% by mass) of the tin oxide-antimony oxide composite fine particles described in No. 1-20033 was added, and distilled water was added thereto to make 1000 ml, thereby obtaining an undercoating coating solution C.

<< Preparation of Undercoating Support >> Thickness (175 μm) used in Example 1 (with anthraquinone dye 1)
m is subjected to a corona discharge treatment on one surface (photosensitive surface) of a biaxially stretched polyethylene terephthalate support having a thickness of 5 m, and the above undercoating coating solution A is coated with a wet coat amount of 5 ml /
m ² and dried at 180 ° C. for 5 minutes.
The dry film thickness was about 0.3 μm. Next, after applying a corona discharge treatment to the back surface (back surface), the undercoating coating solution B was applied with a wet coat amount of 5 ml / m using a bar coater.
^2. Apply so that the dry film thickness is about 0.3 μm.
After drying at 0 ° C for 5 minutes, the undercoating solution C was further coated thereon with a bar coater at a wet coating amount of 3 ml /
m ² , a coating having a dry film thickness of about 0.03 μm, and dried at 180 ° C. for 5 minutes to prepare an undercoat support.

<< Preparation of Photothermographic Material >> On the back side of the undercoating support having the image forming layer, a back layer coating solution was coated at 810 nm with an optical density of 0.8 at an optical density of 0.8 on the back side. Apply the protective layer coating solution at 50 g / m ²
en F. Kistler, Peter M. Sch
"LIQUID FILM COATI" by Weizer
NG "(CHAPMAN &amp; HALL, 19
1997) p. 427, FIG. 11b. After simultaneously coated in the same coater as 1, the image forming layer coating solution 82 ml / m ² from the support side to the opposite surface and the back surface, the intermediate layer coating solution 6.5 ml / m ^2, the protective layer coating solution 12.5ml /
m ² , overcoat layer coating solution 12 ml / m ² at a coating speed of 160 m / min.
30 after passing through the chilled zone (dew point 0 ° C or less)
C., 40% RH, and a wind speed of 20 m / sec. The thus-obtained light-sensitive material had a smoothness (Beck smoothness determined by Oken-type smoothness measurement described in J. TAPPI paper pulp test method No. 5) of 590 seconds for the emulsion surface and 80 seconds for the back surface. .

<< Measurement of Plastic Deformation Rate >> The photothermographic material produced as described above was measured for plastic deformation rate in exactly the same manner as in Example 1.

<Evaluation of streak-like or spot-like scratches> The photothermographic material prepared as described above was cut in half (14 × 1
7 inches), and processed in the same manner as in Example 2 using the thermal developing apparatus shown in FIG. However, 81
Exposure was performed with a 0-nm semiconductor laser (a single output having a maximum output of 35 mW combined into a maximum output of 70 mW) so that the angle between the exposure surface and the laser beam was 55 degrees. The heat development condition is 125 ° from the surface having the photosensitive layer.
Processing (development) at 10 ° C. for 10 seconds. The results obtained are shown in the table.

[0396]

[Table 4]

From the table, it can be seen that the photothermographic material of the present invention has less streak-like or spot-like flaws in the system using the polymer latex dispersed in water than the comparative sample.

[0398]

According to the present invention, there is provided a photothermographic material in which generation of streaks or spots is suppressed even when the photothermographic processing apparatus is used for a long time, an image recording method using the photothermographic material, and an image forming method. Obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing a specific example of a heat development processing apparatus.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 heat drum 2 opposing roller 6 peeling claw 100 thermal developing device 110 feeding unit 120 exposing unit 130 developing unit 140 supply roller pair 141, 142, 143, 145 conveyance roller pair 144 supply roller pair 150 cooling unit F film C film tray L Laser beam

Claims (10)

[Claims] 1. A support having a backing layer on one side and a photosensitive silver halide, an organic silver salt,
In a photothermographic material having an image forming layer containing a reducing agent and a binder for an organic silver salt and at least one surface protective layer thereon, the surface temperature of the photothermographic material on the image forming layer side is preferably 10 or more. A photodevelopment method characterized in that, when a load of 9.8 mN is applied to the surface thereof at a temperature in the range of 60 ° C. to 60 ° C., the plastic deformation rate defined by the following formula (1) is 50% or less. material. Formula (1) Plastic deformation rate (%) = Plastic deformation amount / (Elastic deformation amount + Plastic deformation amount) × 100 2. When a load of 1.96 mN is applied to the surface of the image forming layer when the surface temperature of the image forming layer is in the range from the heat development temperature to the heat development temperature of -40.degree. 2. The photothermographic material according to claim 1, wherein the plastic deformation rate is 50% or less. 3. The photothermographic material according to claim 1, wherein the binder contained in the image forming layer has a glass transition temperature (Tg) of 70 ° C. or more and 105 ° C. or less. 4. The photothermographic material according to claim 1, wherein the surface protective layer on the image forming layer side contains colloidal inorganic fine particles. 5. An antistatic layer containing a conductive metal oxide is provided on a backing layer.
5. The photothermographic material according to any one of items 1 to 4, 6. A method according to claim 1, wherein one of the layers on the image forming layer side contains a silver saving agent.
Item 6. The photothermographic material according to item 1. 7. A scanning exposure of the photothermographic material according to claim 1 using a laser in which an angle between an exposure surface and a laser beam does not become substantially perpendicular. Characteristic image recording method. 8. An image recording method, wherein the photothermographic material according to claim 1 is scanned and exposed using a vertical multi-laser having a non-uniform exposure wavelength. 9. An image recording method, comprising subjecting the photothermographic material according to claim 1 to scanning exposure using two or more lasers. 10. The photothermographic material according to any one of claims 1 to 6, wherein the photothermographic material is transported in a path of 10 μm to 15 μm.
Thermal development is performed using a thermal development processing apparatus having a surface or a roller having at least one 0 μm protrusion per side length of the photothermographic material perpendicular to the transport direction of the photothermographic material. Image forming method of photothermographic material.