JP2003084391A - Thermally developable photosensitive material and image recording method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermally developable photosensitive material excellent in storage stability, having excellent gradation, a high maximum density and low fog and containing a silver saving agent preventing generation of interference fringes and to provide an appropriate image recording method using the thermally developable photosensitive material. SOLUTION: In the thermally developable photosensitive material having a backing layer on one face of a support and an imaging layer comprising at least an organic silver salt, photosensitive silver halide, a reducer and a silver saving agent and a protective layer stacked in this order on the other face of the support, it is characterized in that the silver saving agent has been microencapsulated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photothermographic material and an image recording method using the same.

[0002]

2. Description of the Related Art Conventionally, in the fields of medical treatment and printing plate making, a waste liquid associated with a wet process of an image forming material has been a problem in terms of workability, and in recent years, it has been treated from the viewpoint of environmental protection and space saving. It is strongly desired to reduce the amount of waste liquid.

Therefore, there is a need for a technology relating to a photothermographic material for photographic technology, which enables efficient exposure by a laser imager or a laser imagesetter and can form a clear black image with high resolution. Such a photothermographic material is disclosed, for example, in U.S. Pat. Nos. 3,152,904 and 3,457,075.
No., or D.I. H. Klostervale
er), "Silver System Heat Treated (Th
physically Processed Silver
Systems) (Imaging Processes
And Materials (Imaging Procedures)
ses and Materials) Neblett
e 8th Edition, Sturge, V.E. Wallworth, A.S. Shep
p) edit, p. 279, 1989), etc., a photothermographic material containing an organic silver salt, a photosensitive silver halide grain, and a reducing agent on a support is known. . Since this heat-developable photosensitive material does not use any solution processing chemicals, it is possible to provide the user with a simpler system that does not damage the environment.

Among these, when a compound called a contrast-increasing agent or a silver-saving agent is added to make the amount of silver deposited per unit area the same, the photothermographic material containing neither of the above compounds is added. In comparison with, a photothermographic material capable of obtaining a high density has been proposed.

The above photothermographic material is, for example,
US Pat. Nos. 5,496,695 and 5,545,5
No. 05, No. 5,545, 507, No. 5,637,
No. 449, No. 5,654, 130, No. 5,63
No. 5,339, No. 5,545,515, No. 5,6
86,228, JP-A-10-339929, 11
-84576, 11-95365, 11-95.
No. 366, No. 11-109546, No. 11-1193.
72, 11-119373, JP 2000-35.
6834, JP 2001-27790 A, 2001
Compounds as various contrast enhancers or silver saving agents described in JP-A-174945 (hereinafter referred to as silver saving agents)
Is proposed.

However, in a photothermographic material incorporating a silver saving agent, the color density of the unexposed portion after development may differ depending on the storage conditions of the photothermographic material before heat development.
There was a problem that the desired density was not obtained, or the unexposed area was colored.

On the other hand, JP-A-6-336080 and 7-
No. 125448, No. 8-282115, No. 9-286.
171, 10-226169, 11-5898.
1, JP-A-2000-263940, 2001-1.
8529, 2001-18535, 2001-
No. 30628, No. 2001-42514, No. 2001
Various recording materials using microcapsules have been proposed in Japanese Patent No. 113835 and the like. Further, for the purpose of improving the storage stability of the photothermographic material, JP-A-8-272034 is used.
No. 8, No. 8-278590, No. 9-258365, No. 9-269149, No. 10-207003, No. 11
In JP-A-344790 and JP-A-2000-1979,
A material in which a reducing agent and organic silver are included in microcapsules has been proposed.

[0008]

The present invention has been made in view of the above problems, and an object of the present invention is to provide excellent storage stability, excellent gradation, and high maximum density. Another object of the present invention is to provide a photothermographic material containing a silver-saving agent which has a low fog and prevents the occurrence of interference fringes, and a preferable image recording method using the photothermographic material.

[0009]

The above objects of the present invention have been achieved by the following constitutions.

1. Having a backing layer on one side of the support,
In a photothermographic material, an image forming layer containing at least an organic silver salt, a photosensitive silver halide, a reducing agent and a silver saving agent and a protective layer are laminated in this order on the surface of the support opposite to the backing layer. A photothermographic material, wherein the silver saving agent is encapsulated in microcapsules.

2. 2. The photothermographic material as described in 1 above, wherein the microcapsules containing the silver-saving agent are heat-responsive microcapsules.

3. The average particle size of the microcapsules is 0.
20 to 2.0 μm, The photothermographic material as described in 1 or 2 above.

4. The wall material of the microcapsules is made of polyurethane or polyurea.
4. The photothermographic material according to any one of 3 above.

5. Having a backing layer on one side of the support,
An intermediate layer containing at least a silver saving agent, an organic silver salt, a photosensitive silver halide, an image forming layer containing a reducing agent, and a protective layer were laminated in this order on the surface of the support opposite to the backing layer. In the photothermographic material, the silver saving agent is encapsulated in microcapsules.

6. 6. The photothermographic material as described in 5 above, wherein the microcapsules containing the silver-saving agent are heat-responsive microcapsules.

7. The average particle size of the microcapsules is 0.
20 to 2.0 μm, The heat-developable photosensitive material as described in 5 or 6 above.

8. The wall material of the microcapsule is made of polyurethane or polyurea.
8. The photothermographic material according to any one of 7 above.

9. 9. An image recording, wherein the photothermographic material according to any one of 1 to 8 above is subjected to scanning exposure by using a laser in which an angle between an exposure surface and a laser beam is not substantially vertical. Method.

10. 9. An image recording method, wherein the photothermographic material according to any one of 1 to 8 above is subjected to scanning exposure by using a vertical multi-laser having an exposure wavelength which is not single.

11. 9. An image recording method, wherein the photothermographic material according to any one of 1 to 8 above is subjected to scanning exposure by using two or more lasers.

12. The wavelength of the laser used for scanning exposure is
12. The image recording method as described in any one of 9 to 11 above, which is in a range of 700 to 1200 nm.

As a result of earnest studies on the above problems, the present inventor concludes silver saving by including microcapsules containing a silver saving agent in the image forming layer or the intermediate layer in the photothermographic material. It has been found that the present invention can be achieved and a low fog image can be obtained regardless of the storage condition before heat development, and the present invention has been completed.

First, the photothermographic material of the present invention will be described. The present invention is characterized in that the photothermographic material has microcapsules containing a silver saving agent, and is divided into two modes depending on the layer containing the microcapsules.

In a first aspect of the present invention, a backing layer is provided on one side of a support, and at least an organic silver salt, a photosensitive silver halide and a reducing agent are provided on the side of the support opposite to the backing layer. The photothermographic material is characterized in that an image forming layer containing a silver saving agent contained in microcapsules and a protective layer are laminated in this order.

Next, the microcapsules containing the silver saving agent which is a feature of the present invention will be described in detail.

As the silver-saving agent included in the microcapsules of the present invention, compounds represented by the following general formulas (1) to (14) are preferable.

[0027]

[Chemical 1]

In the general formulas (1) to (14), W represents an electron-withdrawing group, D represents an electron-donating group, and H represents a hydrogen atom. The groups represented by W or D on the same carbon atom may mutually form a cyclic structure,
When W or D has either a trans structure or a cis structure, it may have either structure.

Specific compounds represented by the above general formulas (1) to (14) are described in JP-A No. 11-84576,
11-95366, 11-109546, 1
1-1119373, 11-119372, 11
-119373, 11-231459, special table 20
00-515995, US Pat. No. 5,545,515.
Nos. 5,635,339 and 5,654,130
No. 5,686,228 and the like, it is preferable to select and use the compound at appropriate time.
Further, from the problem of the wall material of the microcapsule described later, as a silver saving agent, a hydroxy group or a salt thereof in the molecule,
A compound that does not contain at least one functional group selected from a mercapto group or a salt thereof, a primary or secondary alkylamino group, a primary or secondary arylamino group may react with the compound during the formation of the wall material, and may be deactivated. It is more preferable because there is no

In addition to the compounds described in the above-mentioned patents, the compounds shown below can be selected and used at appropriate times.

[0031]

[Chemical 2]

[0032]

[Chemical 3]

[0033]

[Chemical 4]

[0034]

[Chemical 5]

[0035]

[Chemical 6]

[0036]

[Chemical 7]

[0037]

[Chemical 8]

[0038]

[Chemical 9]

[0039]

[Chemical 10]

[0040]

[Chemical 11]

[0041]

[Chemical 12]

[0042]

[Chemical 13]

[0043]

[Chemical 14]

[0044]

[Chemical 15]

[0045]

[Chemical 16]

[0046]

[Chemical 17]

[0047]

[Chemical 18]

[0048]

[Chemical 19]

The compound is represented by the general formula (1) to
The compound represented by (14) is not particularly limited to these compounds.

Next, a method for preparing microcapsules containing the silver-saving agent will be described. The method for microencapsulation can be appropriately selected from known methods. As a method for forming microcapsules, for example, a method utilizing coacervation of a hydrophilic wall forming material described in US Pat. No. 2,800,457, US Pat. No. 3,287,154, etc. The interfacial polymerization method described, the method by polymer precipitation described in US Pat. No. 3,418,250, US Pat.
Methods using the isocyanate polyol wall material described in US Pat. No. 6,669, methods using the isocyanate wall material described in US Pat. No. 3,914,511, US Patent No. 4,001,140, etc. Urea-formaldehyde based, urea formaldehyde-resorcinol based wall forming materials, US Pat.
No. 5,455, etc., a method using a wall forming material such as melamine-formaldehyde resin and hydroxybrobil cellulose, Japanese Patent Publication No. 36-9168, etc., an in situ method by polymerization of monomers, British Patent No. 9
No. 52807, electrolytic dispersion cooling method, US Pat. No. 3,111,407, etc., spray drying method, JP-B-7-73069, JP-A-4-101.
885 and the method described in JP-A-9-263057.

The method of microencapsulation is not limited to the above-mentioned method, but when the silver saving agent is solid, the silver saving agent is changed to a hydrophobic organic solvent which is the core of the capsule. An oil phase prepared by dissolving or dispersing is mixed with an aqueous phase in which a water-soluble polymer is dissolved, emulsified and dispersed by a means such as a homogenizer, and then heated to cause a polymer forming reaction at the oil droplet interface, It is preferable to adopt an interfacial polymerization method for forming the microcapsule wall of a polymer substance. The interfacial polymerization method can form capsules having a uniform particle size within a short time.

In the microcapsules containing the silver saving agent of the present invention, the wall material of the microcapsules is impermeable to the substance at room temperature, which prevents contact between substances inside and outside the capsule. However, when heat is applied to the image-forming material during heat development and the capsule wall of the microcapsule reaches a certain temperature or more, which will be described in detail later in the image forming method, the capsule wall becomes substance-permeable, and the capsule wall becomes The thermoresponsive microcapsules capable of contacting internal and external substances are preferable from the viewpoint of storability. In order to obtain such characteristics of the thermoresponsive microcapsules, they can be freely controlled by appropriately selecting materials, additives, etc. used for the wall material of the capsules. The capsule wall material and additives will be described in detail below.

As the capsule wall material of the microcapsule used in the present invention, the capsule wall material used in the above-mentioned forming method can be selected and used at appropriate times. Examples of such capsule wall material include gelatin, polyester, polyamide, polyurea, polyurethane, polyurethane / urea, urea / formalin, and the like. For the production method, for example, “microcapsules-its function and application” (Edited by Tamotsu Kondo, Japan Standards Association, 1991) and the like. In the present invention, polyurea formed by an interfacial polymerization method, polyurethane, and microcapsules containing polyurethane / urea as a film material are particularly preferable because they can control the thermal response suitable for the present invention and the particle size.

Specifically, the microcapsules containing a silverizing agent are prepared by mixing a silver saving agent to be encapsulated with a polyvalent isocyanate, emulsifying and dispersing in water, and then reacting the polyvalent isocyanate with water. It should be noted that the reaction may be heated as necessary.

Examples of the polyvalent isocyanate used here include dimethylene diisocyanate, tetramethylene diisocyanate, hexanemethylene diisocyanate, 2,2-dimethylpentane diisocyanate,
2,2,4-Trimethylpentane diisocyanate, decane diisocyanate, ω, ω'-diisocyanate-
1,3-Dimethylbenzol, ω, ω′-diisocyanate-1,2-dimethylcyclohexanediisocyanate, ω, ω-diisocyanate-1,4-diethylbenzene, ω, ω′-diisocyanate-1,5-dimethylnaphthalene, ω , Ω'-diisocyanate-n-propylbiphenyl, 1,3-phenylene diisocyanate, 1-methylbenzol-2,4-diisocyanate, 1,3-dimethylbenzol-2,6-diisocyanate, naphthalene-1,4-diisocyanate, 1,
1'-Dinaphthyl-2,2'-diisocyanate, biphenyl-2,4'-diisocyanate, 3,3'-dimethylbiphenyl-4,4'-diisocyanate, diphenylmethane-4,4'-diisocyanate, 2,2'-
Dimethyldiphenylmethane-4,4'-diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, 3,3'-dimethoxydiphenylmethane-4,
4'-diisocyanate, 4,4'-diethoxydiphenylmethane-4,4'-diisocyanate, 1-methylbenzol-2,4,6-triisocyanate, 1,
3,5-Trimethylbenzene-2,4,6-triisocyanate, diphenylmethane-2,4,4'-triisocyanate, triphenylmethane-4,4 ', 4'-triisocyanate, tolylene diisocyanate, 1,5
-Naphthylene diisocyanate and the like, and further, a dimer or trimer adduct of each of the above isocyanate compounds (for example, hexamethylene diisocyanate
Mol adduct, hexamethylene diisocyanate 3 mol adduct, 2,4-tolylene diisocyanate 2 mol adduct, 2,4-tolylene diisocyanate 3 mol adduct, and the like, two different types selected from these isocyanates. Adducts of the above isocyanates, and these isocyanates and divalent or trivalent
Valent polyalcohol (preferably polyalcohol having up to 20 carbon atoms, such as ethylene glycol, propylene glycol, pinacol, trimethylolpropane, etc.)
And adducts (for example, an adduct of tolylene diisocyanate and trimethylol propane, an adduct of hexamethylene diisocyanate and trimethylol propane, etc.) and the like. These isocyanate compounds may be used alone or in combination of two or more.

In the above-mentioned method, the polyvalent isocyanate reacts with water to form a polymer film, but polyhydric alcohol or polyvalent amine may be used as a reaction partner.

Specific examples of such polyhydric alcohols include, for example, catechol, resorcin, 3,4-hydroxytoluene, 2,4-dihydroxytoluene and 2,4.
-Dihydroxyethylbenzene, 1,3-naphthalenediol, 1,5-naphthalenediol, O, O'-biphenol, p, p'-biphenol, 2,2-bis (p
-Hydroxyphenyl) propane, 1,1-bis (p-
Hydroxyphenyl) cyclohexane, 2,2-bis (4-hydroxycyclohexyl) propane, bis (4
-Hydroxyphenyl) methane, bis (4-hydroxyphenyl) sulfone, ethylene glycol, diethylene glycol, triethylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentane Diol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, 1,6-hexanediol, 1,1,1-trimethylolpropane, 1,2,6-hexanetriol,
1,3,5-trihydroxybenzene, pentaerythritol, dipentaerythritol, tripentaerythritol, glycerin, 1,4-dihydroxymethylbenzene, 4- (2-hydroxyethoxy) benzenemethanol, 1,4-di (2- (Hydroxyethoxy) benzene, pyrogallol, sorbitol, gallic acid ester and the like can be mentioned. These may be used alone or in combination of two or more. Specific examples of the polyvalent amine include ethylenediamine, trimethylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine and the like.

Furthermore, when the silver saving agent is encapsulated,
An organic solvent may be used as an additive for the purpose of dissolving the silver saving agent. As such an organic solvent, “microcapsules-its function and application” (edited by Yasushi Kondo, Japan Standards Association, 1991) Chapter 2 and "Introduction to Special Paper Chemistry"
(Hiroyuki Moriga, Polymer Publishing, 1975) The organic compounds described in Chapter 2 and the like can be selected and used as needed at appropriate times.

Among them, those having a boiling point of 180 ° C. or higher are preferable for the purpose of preventing evaporation with time. Specifically, paraffin oil, cottonseed oil, soybean oil, corn oil, olive oil, castor oil, fish oil, lard oil, Chlorinated paraffins, chlorinated diphenyls, alkylated biphenyls such as 4,4′-dimethylbiphenyl and 4-isopropylbiphenyl, alkylated naphthalene such as isopropylnaphthalene and diisopropylnaphthalene, 1-phenyl-1-xylylethane, 1-phenyl-1. Examples thereof include diarylethane such as -p-ethylphenylethane, phthalic acid ester such as diethyl phthalate and dibutyl phthalate, and phosphoric acid ester such as tricresyl phosphate. These may be used alone or in combination of two or more, and are usually preferably used in a concentration range of 50% by mass or less based on the polyvalent isocyanate.

When the silver saving agent to be encapsulated in the microcapsules has a low solubility in the high boiling point organic solvent, a low boiling point solvent having a high solubility can be used in combination as an auxiliary solvent. . On the other hand, it is also possible to use only a low boiling point solvent without using the above high boiling point organic solvent, and as such a low boiling point solvent, for example, ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate, methylene chloride, etc. Can be mentioned.

When a hydrophobic substance capable of dissolving the silver saving agent as described above is emulsified in water for microencapsulation, if the emulsification is insufficient, an emulsifier may be further added. Examples of such emulsifiers include gelatin,
Gum arabic, casein, methyl cellulose, hydroxypropyl cellulose, carboxymethyl cellulose,
Polyvinyl alcohol, ethylene-maleic anhydride copolymer, styrene-maleic anhydride copolymer, alkylbenzene sulfonic acid, alkylnaphthalene sulfonate,
Examples thereof include polyoxyethylene sulfate, polyoxyethylene alkyl ether, alkylphenyl ether, and sorbitan fatty acid ester. These may be used alone or in combination of two or more.

The particle size of the microcapsules in the present invention is usually 0.20 to 2.0 μm, more preferably about 0.30 to 1.5 μm.

Further, the amount of the silver saving agent is preferably in the range of usually 0.0001 to 0.5 mol with respect to 1 mol of silver. It is preferable to add the encapsulated microcapsules to the coating liquid for the image forming layer.

The present invention is characterized in that the image forming layer contains microcapsules containing the silver saving agent as described above. However, as will be described in detail later, since the image forming layer coating liquid of the present invention is prepared with an organic solvent, it is necessary to redisperse the microcapsules containing the silver saving agent in the organic solvent.

As a method of redispersing the water-dispersed product in an organic solvent, for example, the prepared microcapsule aqueous dispersion containing the silver-saving agent is filtered off, washed thoroughly with water, and further washed with water. It can be added to the coating liquid for the image forming layer by thoroughly washing and removing water with an organic solvent which is miscible with and does not dissolve the capsule wall material, and then dispersing the water in a necessary organic solvent.

A known dispersant or binder resin may be appropriately selected and used for the purpose of uniformly dispersing the dispersion in an organic solvent or ensuring the liquid stability of the dispersion. Among these, it is preferable to use a binder resin that forms the image forming layer because it has little adverse effect on the image when the image is formed by the image forming method described later.

The above is a method in which microcapsules containing a silver-saving agent are formed in water and then replaced with an organic solvent suitable for addition to the image forming layer forming coating solution. When the solubility of the silverizing agent itself in the organic solvent is extremely low, the formation of microcapsules may be carried out from the beginning in the organic solvent by using the method described in JP-A-7-246329. it can.

Next, the support, the organic silver salt, the photosensitive silver halide, the image forming layer containing a reducing agent, and the protective layer which are essential components in the first embodiment of the present invention will be described in detail.

The resin for forming the support used in the photothermographic material of the present invention is, for example, acrylic resin, polyester, polycarbonate, polyarylate, polyvinyl chloride, polyethylene, polypropylene,
Resin films such as polystyrene, nylon, aromatic polyamide, polyetheretherketone, polysulfone, polyethersulfone, polyimide, polyetherimide, and triacetyl cellulose, and resin films formed by laminating two or more layers of the above resins. Can be mentioned.

In the image recording method to be described later, the support according to the present invention is subjected to heat development after image formation to form an image. Therefore, a support which is stretched into a film and annealed has a dimensional stability. Preferably, the above-mentioned resin is, for example, polyester, polycarbonate, polyarylate, polyetheretherketone, or triacetylcellulose, and biaxially stretched and annealed polyester therein is preferred from the viewpoint of versatility and / or cost. More preferable.

The above-mentioned polyester will be described in more detail. The polyester referred to here is a polymer compound having an ester bond in the molecular main chain, and is a polymer obtained by condensation polymerization of a diol and a dicarboxylic acid. Dicarboxylic acid means terephthalic acid, isophthalic acid, phthalic acid,
It is represented by naphthalene dicarboxylic acid, adipic acid, sebacic acid, etc., and the diol is represented by ethylene glycol, trimethylene glycol, tetramethylene glycol, cyclohexane dimethanol and the like. In the present invention, in particular, polyethylene terephthalate (PET) or its copolymer, polybutylene naphthalate (PBN) or its copolymer,
Polybutylene terephthalate (PBT) or its copolymer, and polyethylene naphthalate (PEN) and its copolymer are preferably used. The repeating unit of these polyesters is 100 or more, especially 150
Or more, and the intrinsic viscosity is preferably 0.6 dl / g or more, more preferably 0.7 dl
/ G or more. In such a case, the film forming stability is excellent and preferable. Of course, these polyesters include known additives such as lubricants, stabilizers, antioxidants, viscosity modifiers, antistatic agents, colorants, and pigments. Etc. can be arbitrarily mixed.

The thickness of the support is usually 50 to 500.
μm, and more preferably 100 to 250 μm.

When the photothermographic material of the present invention is used for medical images, the support may contain a blue dye. Examples of such dyes include Disperse
Dye, Cationic Dye, Basic Dye, Aci
d dye, Reactive dye, Direct dye, V
at dye, Azoic dye, Mordant dye, Ac
id modant dye, Union dye, Solv
ent dye etc. can be selected and used at any time,
Among these, the Solvent dye is preferable from the viewpoint of uniform dispersibility at the time of melt-kneading at the time of forming the support and solubility of the dye at the time of preparing a coating liquid for forming a backing layer described later. Further, in order to prevent sublimation during melting and kneading and to reduce deterioration of the dye during kneading as much as possible, it is preferable that the heat stability is 250 ° C. or higher, and the resin used as a support is extruded. If it is necessary to raise the temperature of the extruder at
A dye having a λmax of 600 to 650 nm is more preferable for the purpose of coloring in blue among the above dyes.

A backing layer may be provided on the surface opposite to the surface on which the image forming layer is laminated on the support for the purpose of transportability, antistatic property, antihalation property, and the like. The layer is composed of a binder resin and various additives added as necessary.

As the binder resin forming the backing layer, a transparent or translucent binder resin which has been conventionally used can be appropriately selected and used. Examples of the binder resin include polyvinyl formal and polyvinyl. Acetoacetal, polyvinyl acetal resins such as polyvinyl butyral, nitrocellulose, cellulose resins such as cellulose acetate butyrate, polystyrene, styrene-acrylonitrile copolymers, styrene-acrylonitrile-acrylic rubber copolymers and other styrene resins, polychlorinated Vinyl, vinyl chloride resin such as vinyl chloride-vinyl acetate copolymer, acrylic resin such as polymethylmethacrylate, polyester, polyurethane, polycarbonate, polyarylate, epoxy resin, phenoxy resin, etc. The recited, may further be used epoxy group-containing compound was assumed to be cured with active energy ray, an acrylic group-containing compound such as a layer forming binder resin. In addition, these binder resins may be used alone or in combination of two or more kinds.

When the above-mentioned binder resin has a hydroxyl group, it may be a metal alkoxide having a plurality of metal alkoxide moieties such as polyfunctional isocyanate compounds, alkoxysilane compounds, and alkoxytitanium compounds known in the art. A crosslinking agent may be added for crosslinking.

As various other additives, it is preferable to contain a filler for the purpose of preventing defective pick-up in the apparatus and ensuring transportability. When the filler is added, the content is in the backing layer forming composition. 0.05-30
It is preferable to contain it in mass%.

Further, the backing layer may contain a lubricant or an antistatic agent in order to improve the slipperiness and the chargeability. Examples of such a lubricant include fatty acid, fatty acid ester and fatty acid amide. , Polyoxyethylene, polyoxypropylene, (modified) silicone oil, (modified) silicone resin, (modified) fluorine compound, (modified)
Fluorine resin, carbon fluoride, wax and the like can be mentioned. Examples of the antistatic agent include cationic surfactants, anionic surfactants, nonionic surfactants, high molecular antistatic agents, metal oxides or conductive polymers, etc. Nipposha, p.
Compounds described in 875-876, US Pat. No. 5,24
The compound etc. which were described in No. 4,773 column 14-20 can be mentioned. Further, for the purpose of preventing halation, a compound having absorption in the oscillation wavelength region of laser, which will be described in detail in the image recording method described later, may be contained as an antihalation agent.

The thickness of the backing layer is usually 0.
About 5 to 25 μm, and more preferably 1.0 to 15 μm. The backing layer may be formed of a single layer or a plurality of layers having different compositions.

Further, within a range that does not impair the effects of the present invention,
Corona discharge treatment, plasma treatment, anchor coat treatment, etc. on the surface of the support on which an antistatic layer is laminated between the support and the backing layer for the purpose of antistatic treatment, and a backing layer is laminated to improve adhesion and coating properties. It may be modified by using the well-known surface modification technique.

Next, the image forming layer containing the silver saving agent contained in the microcapsules will be described in detail.

The photosensitive silver halide, which is an essential component in the image forming layer according to the present invention, preferably has a small average particle size in order to suppress white turbidity after image formation and to obtain good image quality. Particle size is 0.1 μm
Or less, more preferably 0.01 to 0.1 μm, and particularly preferably 0.1.
02-0.08 μm is preferable. The particle size as used herein refers to the diameter of a circle (equivalent circle diameter) having the same area as each particle image observed with an electron microscope.

The silver halide is preferably monodisperse. The monodispersion as used herein means that the monodispersity calculated by the following formula is 40% or less. The particles are more preferably 30% or less, and particularly preferably 20% or less.

Monodispersity (%) = (standard deviation of particle size) /
(Average value of grain size) × 100 The shape of the photosensitive silver halide grain is not particularly limited, but it is preferable that the Miller index [100] plane occupy a high proportion, and this proportion is 50% or more, further, It is preferably 70% or more, and particularly preferably 80% or more. The ratio of Miller index [100] faces is [11] in the adsorption of sensitizing dyes.
T. 1 utilizing the adsorption dependence between the [1] plane and the [100] plane. T
ani, J .; Imaging Sci. , 29,165
(1985).

Another preferred form of photosensitive silver halide is tabular grain. The tabular grains referred to herein mean those having an aspect ratio (r / h) of 3 or more when the square root of the projected area is rμm and the vertical thickness is hμm. Among them, the aspect ratio is preferably 3 or more and 50 or less. The particle size is preferably 0.1 μm or less, and more preferably 0.01 μm to 0.08 μm.
Is preferred. These are US Pat. No. 5,264,337.
No. 5,314,798, No. 5,320,95
No. 8, etc., the target tabular grain can be easily obtained.

The photosensitive halogen composition is not particularly limited and may be any of silver chloride, silver chlorobromide, silver chloroiodobromide, silver bromide, silver iodobromide and silver iodide. The emulsion used in the present invention is a P. Chimie e by Glafkides
t Physique Photographique
(Published by Paul Montel, 1967), G.I.
F. Duffin Photographic Em
ulsion Chemistry (The Foca
I Press, 1966), V.I. L. Zelik
Manning et Coat by Making and Coat
ing Photographic Emulsion
(The Focal Press, 1964) and the like.

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

These metal ions can be introduced into the silver halide in the form of metal complexes or metal complex ions. As the metal complex or metal complex ion, a hexacoordinated metal complex represented by the following general formula is preferable.

[0089] Formula [ML _6] ^m wherein the transition metal M is selected from 6-11 group elements of the periodic table, L is a ligand, m is 0, -, 2-, 3- or 4-
Represents Specific examples of the ligand represented by L include halides (fluorides, chlorides, bromides and iodides), cyanides, cyanates, thiocyanates, selenocyanates, tellurocyanates, azides and aco. Examples include ligands, nitrosyl, thionitrosyl, and the like, with preference given to ako, nitrosyl, thionitrosyl, and the like. When an aco ligand is present, it preferably occupies one or two of the ligands. L may be the same or different.

Particularly preferred examples of M are rhodium (Rh), ruthenium (Ru), rhenium (Re), iridium (Ir) and osmium (Os).

Specific examples of transition metal complex ions are shown below, but the invention is not limited thereto.

1: [RhCl ₆ ] ³ -2: [RuCl ₆ ] ³ -3: [ReCl ₆ ] ³ -4: [RuBr ₆ ] ³ -5: [OsCl ₆ ] ³ -6: [IrCl ₆ ] ^{4 -} 7: [Ru (NO) Cl _5] ^2- 8: [RuBr ₄ (H ₂ O)] ^2- 9: _{[Ru (NO) (H 2 O} ) Cl 4 ] ^- 10: [RhCl ₅ (H ₂ O)] ^2-11 : [Re (NO) Cl ₅ ] ^2-12 : [Re (NO) (CN) ₅ ] ^2-13 : [Re (NO) Cl (CN) ₄ ] ^2-14 : [Rh (NO) ₂ Cl _4] ^- 15: _{[Rh (NO) (H 2 O} ) Cl 4 ] ^- 16: [Ru (NO) (CN) _5] ^2- 17: [Fe (CN) _6] ^3- 18 : [Rh (NS) Cl _5] ^2- 19: [Os (NO) Cl _5] ^2- 20: [Cr (NO) Cl _5] ^2- 21: [Re (NO) Cl _5] ^- 22: [Os (NS) Cl ₄ (TeCN)] ^2- 23: [Ru (NS) Cl _5] ^2- 24: _{[Re (NS) Cl 4 (SeCN} ) ] ^2- 25: [Os (NS) Cl (SCN) 4 ] ^2- 26: [Ir (NO ) Cl ₅ ] ^2- 27: [Ir (NS) Cl ₅ ] ^2-The above ^- mentioned metal ion, metal complex or metal complex ion may be one kind, or may be a combination of the same kind of metal and two or more kinds of different metals. Good. The content of these metal ions, metal complexes or metal complex ions is generally 1 × 10 ⁻⁹ to 1 × 10 ⁻² mol per mol of silver halide, and preferably 1 × 10 ^{−. It is 8} to 1 × 10 ⁻⁴ mol.

The compounds providing these metals are preferably added at the time of silver halide grain formation and incorporated into the silver halide grains. Preparation of silver halide grains, that is, nucleation, growth, physical ripening, chemical It may be added at any stage before and after the sensitization, but it is particularly preferable to add it at the stage of nucleation, growth and physical ripening, and more preferable to add at the stage of nucleation and growth. It is preferably added at the stage of nucleation.

Upon addition, the silver halide grains may be dividedly added several times, and may be uniformly contained in the silver halide grains.
-306236, 3-167545, 4-76
No. 534, No. 6-110146, No. 5-273683.
It is also possible to contain the particles having a distribution as described in No. Preferably, it can have a distribution inside the particles.

These metal compounds can be added after being dissolved in water or a suitable organic solvent (for example, alcohols, ethers, glycols, ketones, esters, amides). A method of adding an aqueous solution of a compound powder or an aqueous solution in which a metal compound and NaCl or KCl are dissolved together to a water-soluble silver salt solution or a water-soluble halide solution during grain formation, or a silver salt solution and a halide solution Is added as a third aqueous solution when they are simultaneously mixed, a method of preparing silver halide grains by a three-liquid simultaneous mixing method, a method of charging a necessary amount of an aqueous solution of a metal compound into a reaction vessel during grain formation, or There is a method of adding and dissolving another silver halide grain which is previously doped with a metal ion or a complex ion at the time of preparing the silver halide. In particular, a method of adding an aqueous solution of a powder of a metal compound or an aqueous solution in which a metal compound and NaCl or KCl are dissolved together to a water-soluble halide solution is preferable.

When added to the surface of the particles, a necessary amount of an aqueous solution of the metal compound may be added to the reaction vessel immediately after the particles are formed, during or during physical ripening, or at the end of chemical ripening.

In the present invention, the photosensitive silver halide grains may or may not be desalted after grain formation, but when desalting is performed, the noodle method, flocculation method and the like are known in the art. It can be desalted by washing with water according to the method described above.

The silver halide grains used in the present invention are:
It is preferably chemically sensitized. As a preferable chemical sensitization method, as well known in the art, for example, a sulfur sensitization method, a selenium sensitization method, or a tellurium sensitization method can be used. In addition, a noble metal sensitization method such as a gold compound, platinum, palladium, or iridium compound, or a reduction sensitization method can be used.

Known compounds can be used as the compounds preferably used in the above-mentioned sulfur sensitization method, selenium sensitization method, and tellurium sensitization method. For example, JP-A-7-12876.
The compounds described in No. 8 and the like can be used. Examples of tellurium sensitizers include diacyl tellurides, bis (oxycarbonyl) tellurides, bis (carbamoyl) tellurides, diacyl tellurides, bis (oxycarbonyl) ditellurides, bis (carbamoyl) ditellurides, P = Compounds having a Te bond, tellurocarboxylic acid salts, Te-organyl tellurocarboxylic acid esters, di (poly) tellurides, tellurides, tellurols, telluroacetals, tellurosulfonates, P-
A compound having a Te bond, a Te-containing heterocycle, a tellurocarbonyl compound, an inorganic tellurium compound, a colloidal tellurium, or the like can be used.

Compounds preferably used in the noble metal sensitization method include, for example, chloroauric acid, potassium chloroaurate, potassium aurithiocyanate, gold sulfide, gold selenide, or US Pat. No. 2,448,060 and British Patent No. The compounds described in 618,061 and the like can be preferably used.

Specific compounds used in the reduction sensitization method include ascorbic acid and thiourea dioxide, as well as stannous chloride, aminoiminomethanesulfinic acid,
A hydrazine derivative, a borane compound, a silane compound, a polyamine compound or the like can be used. Also, the emulsion p
Reduction sensitization can be performed by aging while maintaining H at 7 or more or pAg at 8.3 or less. Also, reduction sensitization can be performed by introducing a single addition portion of silver ions during grain formation.

The organic silver salt contained in the image forming layer according to the present invention is a reducible silver source and an organic acid containing a reducible silver ion source. Examples of the organic acid used in the present invention include an aliphatic carboxylic acid, a carbocyclic carboxylic acid, a heterocyclic carboxylic acid, a heterocyclic compound, and the like, and particularly long-chain (10 to 30, preferably 15) ~ 25
Aliphatic carboxylic acids having the number of carbon atoms of (4) and heterocyclic carboxylic acids having a nitrogen-containing heterocycle are preferably used. Further, an organic silver salt complex in which the ligand has a total stability constant for silver ions of 4.0 to 10.0 is also useful.

Examples of such an organic acid silver salt include Re
Search Disclosure (hereinafter abbreviated as RD) Nos. 17029 and 29963. Among them, silver salts of fatty acids are preferably used, and particularly preferably used are silver behenate, silver arachidate and silver stearate.

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

In the present invention, the organic silver salt preferably has an average particle size of 1 μm or less and is monodisperse. With the average particle size of the organic silver salt, particles of the organic silver salt are, for example, spherical,
In the case of rod-like or tabular grains, it means the diameter when considering a sphere equivalent to the volume of organic silver salt grains. The average particle size is preferably 0.01 to 0.8 μm, particularly 0.05 to
0.5 μm is preferable. The monodisperse has the same meaning as in the case of silver halide, and the monodispersity is preferably 1 to 30%.
Is. In the present invention, the organic silver salt has an average particle size of 1 μm.
The following monodisperse particles are more preferable, and an image with a high density can be obtained by setting the content in this range. Further, the tabular grains of the organic silver salt preferably have 60% or more of the total organic silver. The tabular grains of an organic silver salt as used in the present invention have the same meaning as the tabular grains of the photosensitive silver halide described above, and have an aspect ratio of 3 or more.

Such organic silver particles are preferably preliminarily dispersed with a binder, a surfactant and the like, if necessary, and then dispersed and pulverized by a media disperser or a high pressure homogenizer. For the above-mentioned preliminary dispersion, for example, a general stirrer such as an anchor type or a propeller type, a high speed rotating centrifugal radiating stirrer (dissolver), or a high speed rotating shearing stirrer (homomixer) can be used. Further, as the above-mentioned media disperser, it is possible to use a rolling mill such as a ball mill, a planetary ball mill, a vibrating ball mill or the like, a bead mill which is a medium stirring mill, an attritor, or other basket mill, and a wall as a high pressure homogenizer. Various types such as a type that collides with a plug or the like, a type that divides the liquid into a plurality of liquids and then collides with each other at high speed, a type that passes through a thin orifice, and the like can be used.

In the devices used for dispersing the organic silver particles used in the present invention, as the material of the member with which the organic silver particles come into contact, for example, ceramics such as zirconia, alumina, silicon nitride, boron nitride, etc. or diamond. Is preferably used, and particularly preferably zirconia is used.

As the reducing agent contained in the image forming layer according to the invention, those known in the art can be used. Examples thereof include phenols, polyphenols having two or more phenol groups, Naphthols, bisnaphthols, polyhydroxybenzenes having two or more hydroxyl groups, polyhydroxynaphthalenes having two or more hydroxyl groups, ascorbic acids, 3-pyrazolidones, pyrazolin-5-ones, pyrazolines, phenylene Examples thereof include diamines, hydroxylamines, hydroquinone monoethers, hydrooxamic acids, hydrazides, amidoximes, N-hydroxyureas and the like.

Among the above reducing agents, when an aliphatic carboxylic acid silver salt is used as the organic silver salt, preferred reducing agents include polyphenols in which two or more phenol groups are linked by an alkylene group or sulfur, particularly An alkyl group (eg, methyl group, ethyl group, propyl group, t-butyl group, cyclohexyl group, etc.) or an acyl group (eg, acetyl group, propionyl group, etc.) at least at one position adjacent to the hydroxy-substituted position of the phenol group. ) Is a polyphenol in which two or more of the substituted phenol groups are linked by an alkylene group or sulfur, for example, 1,1-bis (2-hydroxy-3,5-dimethylphenyl) -3,
5,5-trimethylhexane, 1,1-bis (2-hydroxy-3-t-butyl-5-methylphenyl) methane, 1,1-bis (2-hydroxy-3,5-di-t-
Butylphenyl) methane, 1,1-bis (2-hydroxy-3-methyl-5-t-butylphenyl) methane,
1,1-bis [2-hydroxy-3-methyl-5- (1
-Methylcyclohexyl) phenyl] methane, (2-hydroxy-3-t-butyl-5-methylphenyl)-
(2-hydroxy-5-methylphenyl) methane, 6,
6'-benzylidene-bis (2,4-di-t-butylphenol), 6,6'-benzylidene-bis (2-t-)
Butyl-4-methylphenol), 6,6'-benzylidene-bis (2,4-dimethylphenol), 1,1-
Bis (2-hydroxy-3,5-dimethylphenyl)-
2-methylpropane, 1,1,5,5-tetrakis (2
-Hydroxy-3,5-dimethylphenyl) -2,4-
Ethyl pentane, 2,2-bis (4-hydroxy-3,
5-dimethylphenyl) propane, 2,2-bis (4-
Hydroxy-3,5-di-t-butylphenyl) propane etc. U.S. Pat. Nos. 3,589,903 and 4,02
1,249 or British Patent Nos. 1,486,148 and Japanese Patent Laid-Open Nos. 51-51933 and 50-36.
110, 50-116023, 52-8472.
7, JP-A-2001-56527, 2001-424.
69, 2001-92075 or Japanese Patent Publication No. 51-3
5727 and the bisnaphthols described in U.S. Pat. No. 3,672,904, such as 2,2'-dihydroxy-1,
1'-binaphthyl, 6,6'-dibromo-2,2'-dihydroxy-1,1'-binaphthyl, 6,6'-dinitro-2,2'-dihydroxy-1,1'-binaphthyl,
Bis (2-hydroxy-1-naphthyl) methane, 4,
4'-dimethoxy-1,1'-dihydroxy-2,2 '
-Binaphthyl and the like, and further sulfonamide phenols or sulfonamide naphthols as described in U.S. Pat. No. 3,801,321, such as 4-benzenesulfonamidephenol, 2-benzenesulfonamidephenol, 2, 6-dichloro-4-benzenesulfonamide phenol, 4-benzenesulfonamide naphthol and the like can be mentioned.

The amount of the reducing agent contained in the image forming layer of the present invention varies depending on the type of the organic silver salt and the reducing agent and other additives, but is generally 0.0 per mol of the organic silver salt.
It is 5 to 10 mol, preferably 0.1 to 3 mol. Further, within the range of this addition amount, two or more kinds of the above-mentioned reducing agents may be used in combination.

Further, in the present invention, a binder resin is used in the image forming layer in order to retain the above-mentioned essential components. As such a binder resin, the binder resin described in detail in the above backing layer can be appropriately selected and used within a range not impairing the object of the present invention. However, since it is necessary to disperse and retain the above organic silver salt compound in a binder resin, a resin having a hydroxyl group or a carboxyl group or a salt thereof, or a sulfonic acid or a salt thereof in the molecule is preferable, and a polyvinyl acetal resin, cellulose Resins, phenoxy resins, further, such as the introduction of the functional group, modified vinyl chloride resin, modified polyester, modified polyurethane, modified epoxy resin, modified acrylic resin, and the like, these are used alone. Alternatively, two or more kinds of resins may be used in combination.

When the binder resin has a hydroxyl group or active hydrogen, a metal having a plurality of metal alkoxide moieties such as polyfunctional isocyanate compounds, alkoxysilane compounds, and alkoxytitanium compounds known in the art in the molecule. The film strength may be improved by adding a crosslinking agent such as an alkoxide.

Further, in the image forming layer according to the present invention, in addition to the above-mentioned essential components and binder resin, if necessary, an antifoggant, a toning agent, a sensitizing dye, a substance exhibiting supersensitization (hereinafter (Abbreviated as supersensitizer) may be added.

As such an antifoggant, for example,
For example, Japanese Examined Patent Publication No. 54-44212, Japanese Examined Publication No. 51-9694
No. 55-140833, US Pat. No. 3,873.
No. 4,946 and 4,756,999.
Such as -C (X ₁) (X₂) (X₃) (This
X here₁And X₂Represents a halogen atom, X₃Is hydrogen
Represents a halogen atom) and has one or more substituents represented by
Heterocyclic compounds, JP-A-9-288328 and JP-A-9-288328
-90550, US Pat. No. 5,028,523 and
European Patent Nos. 600,587 and 605,981;
No. 631,176 and other such compounds,
The compounds exemplified below may be used alone or in combination of two or more.
You may use it.

[0115]

[Chemical 20]

[0116]

[Chemical 21]

Examples of the toning agent added for the purpose of improving the silver color tone after development include, for example, imides (eg, phthalimide); cyclic imides, pyrazolin-5-ones, and quinazolinones (eg, succinimide, 3). -Phenyl-2-pyrazolin-5-one, 1-phenylurazole, quinazoline and 2,4-thiazolidinedione); naphthalimides (e.g. N-hydroxy-1,8-.
Naphthalimide); cobalt complex (for example, hexamine trifluoroacetate of cobalt), mercaptans (for example, 3-mercapto-1,2,4-triazole); N- (aminomethyl) aryldicarboximides (for example, N-). (Dimethylaminomethyl) phthalimide); a combination of blocked pyrazoles, isothiuronium derivatives and certain photobleaching agents (eg, N, N'-hexamethylene (1-carbamoyl-3,5-dimethylpyrazole)). , 1,8- (3,6-dioxaoctane) bis (isothiuronium trifluoroacetate), and 2-
(Tribromomethylsulfonyl) benzothiazole combination); merocyanine dyes (eg 3-ethyl-
5-((3-ethyl-2-benzothiazolinylidene (benzothiazolinylidene))-1-methylethylidene)-
2-thio-2,4-oxazolidinedione); phthalazinone, a phthalazinone derivative or a metal salt of these derivatives (for example, 4- (1-naphthyl) phthalazinone, 6-
Chlorophthalazinone, 5,7-dimethyloxyphthalazinone, and 2,3-dihydro-1,4-phthalazinedione); a combination of phthalazinone and a sulfinic acid derivative (eg, 6-chlorophthalazinone + sodium benzenesulfinate) Or 8-methylphthalazinone + sodium p-trisulfonate); a combination of phthalazine + phthalic acid; phthalazine (including an adduct of phthalazine) and maleic anhydride, and phthalic acid, 2,3-naphthalenedicarboxylic acid or o A combination with at least one compound selected from phenylene acid derivatives and their anhydrides (eg phthalic acid, 4-methylphthalic acid, 4-nitrophthalic acid and tetrachlorophthalic anhydride); quinazolinediones, benzoxazine, Naltoxazine derivatives; Benzoki Jin-2,4-diones (for example,
1,3-benzoxazine-2,4-dione); pyrimidines and asymmetric-triazines (eg 2,4-dihydroxypyrimidine), and tetraazapentalene derivatives (eg 3,6-dimercapto-1, 4-diphenyl-1H, 4H-2,3a, 5,6a-tetraazapentalene). Preferred toning agents include phthalazone and phthalazine.

The toning agent may be added to the protective layer described later as long as the object of the present invention is not impaired.

As the sensitizing dye, for example, in the case of an argon ion laser light source, JP-A-60-162 is used.
247, JP-A-2-48635, and US Pat. No. 2,1.
No. 61,331, West German Patent No. 936,071, Japanese Patent Application No. 3-189532, etc.
No. 0-62425, No. 54-18726, No. 59-1
No. 02229, Trinuclear cyanine dyes, Japanese Patent Application No.
-103272, merocyanines, LEDs
For the light source and the infrared semiconductor laser light source, Japanese Patent Publication No. 48
-42172, 51-9609, 55-398.
18, JP-A-62-284343, JP-A-2-10.
JP-A-59-191032 for thiacarbocyanines and infrared semiconductor laser light sources described in JP-A-5135.
And tricarbocyanines described in JP-A No. 60-80841, JP-A-59-192242 and JP-A-3-67.
No. 242 described in the general formulas (IIIa) and (IIIb)
-Dicarbocyanines and the like containing a quinoline nucleus are advantageously selected. Furthermore, the wavelength of the infrared laser light source is 750 nm
If the wavelength is more than 800 nm, more preferably 800 nm or more, in order to deal with a laser having such a wavelength range, it is disclosed in JP-A-4-18.
No. 2639, No. 5-341432, and Japanese Patent Publication No. 6-523
87, No. 3-10931, US Pat. No. 5,441,
The sensitizing dyes described in JP-A No. 866, JP-A No. 7-13295 and the like are preferably used.

As a supersensitizer, RD1764 is used.
3, the compounds described in JP-B-9-25500, JP-B 43-4933, JP-A-59-19032, JP-A-59-192242, JP-A-5-341432, etc. may be selected and used in a timely manner. In the present invention, a heteroaromatic mercapto compound represented by the following general formula (M) and a disulfide compound represented by the general formula (Ma) which substantially produces the above mercapto compound can be used.

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

The above heteroaromatic ring is, for example, a halogen atom (for example, Cl, Br, I), a hydroxy group, an amino group, a carboxyl group, an alkyl group (for example, one or more carbon atoms, preferably 1 to Those having 4 carbon atoms) and alkoxy groups (eg one or more carbon atoms,
Preferably, it may have a substituent selected from the group consisting of (having 1 to 4 carbon atoms).

In the present invention, it is more preferable to use the following thiuronium compounds as supersensitizers for high sensitivity.

[0124]

[Chemical formula 22]

[0125]

[Chemical formula 23]

The supersensitizer is used in an amount of 0.001 to 1 per mol of silver in the image forming layer containing an organic silver salt and silver halide grains.
It is preferably used in the range of 1.0 mol, and particularly preferably in the range of 0.01 to 0.5 mol per mol of silver.

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

A typical compound is crown ether, which was synthesized by Pederson described below in 1967, and has been synthesized in large numbers since its unique report.
These compounds are C.I. J. Pederson, Jou
rnal of American chemical
society vol, 86 (2495), 701
7-7036 (1967), G.I. W. Gokel, S .;
H, Korzeniowski, "Macrocycl
ic polyethr synthesis ”, Sp
Ringer-Vergal, (1982) and the like.

Further, in the image forming layer according to the present invention, in addition to the above-mentioned additives, for example, a surfactant, an antioxidant,
You may use a stabilizer, a plasticizer, an ultraviolet absorber, a coating aid, etc. These additives are RD Item 17029.
The compounds described in (June 1978, p. 9 to 15) can be appropriately selected and used within a range that does not impair the object of the present invention.

In the present invention, the image forming layer may be a single layer, or may be composed of a plurality of layers having the same composition or different compositions. When a plurality of layers are provided, the microcapsules according to the present invention may be embedded. The silver forming agent may be added to all layers or may be added to a specific layer. Also,
A silver saving agent which is not included in the microcapsules may be added within a range that does not impair the object of the present invention. The thickness of the image forming layer is usually 5 to 20 μm.

The protective layer used in the photothermographic material of the first aspect is composed of the binder resin described in the backing layer and / or the image forming layer and additives which are added as necessary. Can be appropriately selected and used.

The additive to be added to the protective layer preferably contains a filler for the purpose of preventing damage to the image after heat development and ensuring transportability. When the filler is added, the content is 0.05-30 mass% in the forming composition
It is preferable to contain.

Further, the protective layer may contain a lubricant and an antistatic agent in order to improve the slipperiness and the electrification property, and as these compounds, the lubricant used in the backing layer,
An antistatic agent can be appropriately selected and used.

Further, in the case where the binder resin of the protective layer has a hydroxyl group or active hydrogen within the range that does not impair the object of the present invention, conventionally known polyfunctional isocyanate compounds, alkoxysilane compounds, alkoxytitanium compounds, etc. A crosslinking agent such as a metal alkoxide having a plurality of metal alkoxide moieties in the molecule may be added to improve the film strength. The amount of these additives added is 0.01 to 20% by mass of the protective layer forming component. The degree is preferably, and more preferably 0.05 to 10% by mass.

In the present invention, the protective layer may be a single layer,
It may be composed of a plurality of layers having the same composition or different compositions. The thickness of the protective layer is usually 1.0 to 5.0 μm.

Further, the backing layer, the image forming layer and the protective layer provided in the first aspect of the present invention are prepared by dissolving or dispersing the components described above in a solvent to prepare a coating liquid.

As the solvent, those having a solubility parameter value of 7.4 to 15.0 shown in "Solvent Pocket Book" edited by the Society of Synthetic Organic Chemistry are used. It is preferable from the viewpoint of drying property during production. The solubility parameter here is generally δ [(cal / cm
³ ) ^1/2 ], and the solvent used in the coating liquid for forming each layer is, for example, acetone (9.
9), isophorone (9.1), ethyl amyl ketone (8.2), methyl ethyl ketone (9.3), methyl isobutyl ketone (8.4), cyclopentanone (10.
4), cyclohexanone (9.9) and the like. As alcohols, methyl alcohol (14.5), ethyl alcohol (12.7), n-propyl alcohol (11.9), isopropyl alcohol (11.5),
n-Butyl alcohol (11.4), isobutyl alcohol (10.5), t-butyl alcohol (10.
6), 2-butyl alcohol (10.8), diacetone alcohol (9.2), cyclohexanol (11.
4) etc. are mentioned. As glycols, ethylene glycol (14.6) and diethylene glycol (12.
1), triethylene glycol (10.7), propylene glycol (12.6) and the like. Examples of ether alcohols include ethylene glycol monomethyl ether (11.4) and diethylene glycol monoethyl ether (10.2). As ethers, diethyl ether (7.4) and tetrahydrofuran (9.
1), 1,3-dioxolane (10.2), 1,4-dioxane (10.0) and the like.

Examples of the esters include ethyl acetate (9.1), n-butyl acetate (8.5) and isobutyl acetate (8.3). As hydrocarbons, n-heptane (7.4), cyclohexane (8.
2), toluene (8.9), xylene (8.8) and the like. Methyl chloride (9.7), chloroform (9.3), etc. are mentioned as chlorides. In addition, nitrogen-containing,
Dimethylformamide (10.8) as a sulfur-containing solvent,
Dimethyl sulfoxide (12.0), acrylonitrile (10.5), pyridine (10.7) and the like can be mentioned.
However, it is not limited to these as long as the effect of the present invention is not impaired, and further, these solvents are alone,
Alternatively, several types can be used in combination.

The content of the solvent in the photothermographic material can be adjusted by changing the conditions such as temperature conditions in the drying step after the coating step, and the amount of the residual solvent contained in the photothermographic material is preferably 5 to 1000 mg / m ² in a total amount, more preferably 10-300 mg / m ^2.

When dispersion is required when forming the coating liquid, two roll mill, three roll mill, ball mill, pebble mill, covol mill, tron mill, sand mill, sand grinder, Sqegvari attritor, high speed impeller disperser, high speed A conventionally known disperser such as a stone mill, a high speed impact mill, a disperser, a high speed mixer, a homogenizer, an ultrasonic disperser, an open kneader, and a continuous kneader can be appropriately selected and used.

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

The protective layer is not particularly limited as long as it does not damage the image forming layer, but the solvent used for the protective layer forming coating solution is not limited to the image forming layer. When there is a possibility of melting of the above, in the above-mentioned coater station, an extrusion type extrusion coater, a gravure roll coater, a bar coater or the like can be used. When using a coating method such as a gravure roll coater or a bar coater, which is in contact with these,
The rotation direction of the gravure roll or the bar may be forward or reverse with respect to the conveying direction, and in the case of forward rotation, a constant speed or a peripheral speed difference may be provided.

Further, although coating and drying may be repeated for each layer as described above, it is also possible to perform multi-layer coating by a wet-on-wet system and dry. In that case, reverse roll coater, gravure roll coater, air doctor coater, blade coater, air knife coater, squeeze coater, impregnation coater, bar coater, transfer roll coater, kiss coater, cast coater, spray coater, slide coater, extrusion type It can be applied in combination with an extrusion coater.In such a wet-on-wet multi-layer coating, since the upper layer is applied while the lower layer remains in a wet state, adhesion between the upper and lower layers The property is improved.

Further, in the present invention, when the image forming layer forming coating liquid is applied on the support, the surface of the support is subjected to flame treatment, ozone treatment, glow discharge treatment, corona discharge treatment, plasma treatment, vacuum ultraviolet ray irradiation. It is preferable to apply the image forming layer forming coating liquid after at least one surface treatment selected from treatment, electron beam irradiation treatment and radiation irradiation treatment. By treating the surface of the support in this manner, The adhesion between the support and the image forming layer can be made stronger.

The second embodiment of the present invention is an intermediate product having a backing layer on one side of a support and containing microcapsules containing at least a silver saving agent on the side of the support opposite to the backing layer. The photothermographic material is characterized in that a layer, an organic silver salt, a photosensitive silver halide, an image forming layer containing a reducing agent, and a protective layer are laminated in this order.

The intermediate layer in this embodiment may be composed of a binder resin and various additives such as a filler and a cross-linking agent which are optionally added, in addition to the microcapsules containing the silver-saving agent which is an essential component. it can.

As the silver-saving agent contained in the microcapsules, which is an essential component in the second aspect, the silver-saving agent described in the first aspect can be appropriately selected and used. It can be prepared by a method similar to the microcapsule preparation method described in the embodiment.

The average particle size of the microcapsules containing the silver saving agent contained in the intermediate layer is usually 0.20 to 1.0.
μm, more preferably 0.30 to 0.08 μm.

Further, the amount of the silver saving agent is usually 0.0005 to 5 mol per 1 mol of silver contained in the image forming layer.
The amount is preferably in the range of 0.5 mol, and it is preferable to add microcapsules encapsulating the silver-saving agent to the intermediate layer forming coating solution in such a range.

Examples of the binder resin used in the intermediate layer include polyvinyl alcohol, gelatin, casein, polyvinylpyrrolidone, polyurethane resin, polyester resin, polyvinyl acetal resin, cellulose resin, phenoxy resin, epoxy resin, phenol novolac. Resin, polycarbonate resin, acrylic resin, or styrene resin, polyolefin resin,
A modified product obtained by introducing a hydroxyl group or a carboxylic acid into a vinyl chloride resin, a silicone resin or the like can be appropriately selected and used. These resins may be used alone or in combination of two or more.

As the additive to be added to the intermediate layer, in the first embodiment, the additive to be added to the image forming layer, the protective layer, and the backing layer provided as necessary may be appropriately selected and used. it can.

The thickness of the intermediate layer is usually 0.10 to
It is 3.0 μm, preferably 0.30 to 2.0 μm.

As described above, by providing the intermediate layer containing the microcapsules containing the silver saving agent, not only the object of the present invention, silver saving, but also the support and the image forming layer can be achieved. The film attachment can be improved.

In order to form the intermediate layer, the components described above are dissolved or dispersed in a solvent to prepare an intermediate layer forming coating liquid. As the solvent, water, hydrocarbon-based solvent, alcohol-based solvent, ketone-based solvent, ether-based solvent, halogen-based solvent, nitrogen-containing solvent, sulfur-containing solvent, such as those that do not dissolve the capsule wall agent of the microcapsule It can be used without particular limitation.

Among these, when a water-soluble resin or a water-based latex is used as the binder, the microcapsules themselves containing the silver-saving agent may be used as an aqueous dispersion without solvent substitution.

Further, in order to apply the prepared intermediate layer forming coating liquid, various known coater stations described above can be selected and used at appropriate times.

Further, the coating and drying of the image forming layer and the protective layer may be repeated for each layer after the coating and drying of the intermediate layer. However, depending on the kind of the solvent of the coating liquid, wet-on-
Wet type intermediate layer and image forming layer, or intermediate layer,
The image forming layer and the protective layer may be simultaneously coated in a multilayer and dried. In that case, it can be applied by a combination of the above-mentioned various coaters and an extrusion type extrusion coater, and in the multi-layer coating in such a wet-on-wet system, the lower layer is in a wet state. Since the upper layer is applied up to, the adhesion between the upper and lower layers is improved.

In the present invention, when the intermediate layer forming coating liquid is applied onto the support, the surface of the support is subjected to flame treatment, ozone treatment, glow discharge treatment, corona discharge treatment, plasma treatment,
It is preferable to apply at least one kind of surface treatment selected from vacuum ultraviolet ray irradiation treatment, electron beam irradiation treatment and radiation irradiation treatment, and then apply the image forming layer forming coating liquid, and thus the surface of the support is treated. Thereby, the adhesion between the support and the intermediate layer can be made stronger.

In addition to the above-mentioned intermediate layer, as the backing layer, the image forming layer and the protective layer provided in the second embodiment, those described in detail in the first embodiment can be appropriately selected and used.

In the present invention, when the photothermographic material of the first aspect is prepared, a microcapsule containing a silver saving agent is included between the support and the image forming layer for the purpose of improving adhesion. An intermediate layer containing no capsules may be provided, or microcapsules containing a silver saving agent may be contained in both the intermediate layer and the image forming layer.

Next, the image recording method suitable for the above photothermographic material will be described in detail. The image recording method of the present invention is roughly classified into three modes depending on the angle formed by the exposure surface and the laser beam, the wavelength of the laser, and the number of lasers used, which may be performed alone or in two or more types. The modes may be combined, and a clear image without interference fringes can be obtained by using such an image forming method.

As a first aspect of the image recording method of the present invention, an image is formed by scanning exposure using laser light in which the angle between the exposed surface of the photothermographic material and the laser light is not substantially perpendicular. Is formed. In this way, by shifting the incident angle from the vertical, even if reflected light occurs at the interlayer interface, the optical path difference reaching the image forming layer becomes large, so that scattering or attenuation of the laser light in the optical path occurs. The interference fringes are less likely to occur.
It should be noted that, here, "not substantially vertical" means an angle that is closest to vertical during laser scanning, and is preferably 5
It means 5 degrees or more and 88 degrees or less, more preferably 60 degrees or more and 86 degrees or less, and further preferably 65 degrees or more and 84 degrees or less.

The second aspect of the image recording method of the present invention is characterized in that an image is formed by scanning exposure using a vertical multi-laser having an exposure wavelength which is not single. When scanning with such a vertical multi-laser light having a width in the wavelength, compared with the vertical single-mode scanning laser light,
The generation of interference fringes is reduced. The vertical multi as used herein means that the exposure wavelength is not single, and normally the distribution of the exposure wavelength is 5 nm or more, preferably 10 nm or more. There is no particular upper limit on the distribution of exposure wavelength,
Usually, it is about 60 nm.

Furthermore, the third aspect of the image recording method of the present invention is characterized in that an image is formed by scanning exposure using two or more lasers.

As an image recording method using a plurality of lasers as described above, it is used in an image writing means of a laser printer or a digital copying machine for writing an image for each plural lines in one scanning because of the demand for higher resolution and higher speed. This is a known technique and is known, for example, from Japanese Patent Application Laid-Open No. 60-166916. This is a method in which a laser beam emitted from a light source unit is deflected and scanned by a polygon mirror and an image is formed on a photoconductor through an fθ lens or the like. This is the same laser scanning optical device as that of a laser imager in principle. Is.

The image formation of the laser beam on the photosensitive member in the image writing means of the laser printer or the digital copying machine is performed from one laser beam image forming position because the image is written in plural lines by one scanning. The next laser beam is imaged with a shift of one line. Specifically, the two light beams are close to each other in the sub-scanning direction on the image surface at intervals of several tens of μm, and the printing density is 400 dpi (in the present invention, 1 inch per 1 inch, that is, 2.54 cm). The dot printing density is defined as dpi (dot per inch)), and the pitch of two beams in the sub-scanning direction is 6
It is 42.3 μm at 3.5 μm and 600 dpi. Unlike such a method in which the resolution is shifted in the sub-scanning direction, the present invention is characterized by forming two or more lasers at the same location by changing the incident angle and condensing on the exposure surface to form an image. At this time, one normal 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 preferably within the range. By doing so, the energy is secured on the exposed surface, but the reflection of each laser beam to the image forming layer is reduced due to the low exposure energy of the laser, and the occurrence of interference fringes is suppressed.

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

Furthermore, in the image recording methods of the above-mentioned first, second and third aspects, the laser used for scanning exposure is generally well known, that is, a ruby laser, Y
Solid-state lasers such as AG lasers and glass lasers; He-Ne
Laser, Ar ion laser, Kr ion laser, CO ₂
Laser, CO laser, He-Cd laser, N ₂ laser,
Gas laser such as excimer laser; InGaP laser,
AlGaAs laser, GaAsP laser, InGaAs
Laser, InAsP laser, CdSnP ₂ laser, Ga
A semiconductor laser such as an Sb laser; a chemical laser, a dye laser, or the like can be selected and used at any time depending on the application, but among these, a semiconductor laser having a wavelength of 700 to 1200 nm is used because of problems of maintenance and the size of the light source. Is preferred.

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

[0170]

EXAMPLES The present invention will now be described in detail with reference to examples, but the present invention is not limited thereto. In addition, water in the text represents ion-exchanged water, and% represents mass% unless otherwise specified.

<Preparation of Microcapsule Dispersion Liquid Encapsulating Silver Saving Agent> (Preparation Method 1) 6.0 g of a silver saving agent (described in Tables 1 and 2), 10.0 g of ethyl acetate, and an isocyanate compound [Mitsui Takeda] Takenate D110N manufactured by Chemical Co., Ltd.] 4.0
g, urethane resin [Dainippon Ink and Chemicals Co., Ltd., Vernock D750] 8.0 g and high boiling point solvent [Kureha Chemical Co., Ltd., KMC113] 12.0 g were dissolved, and this solution and solid 5 An aqueous solution of polyvinyl alcohol dissolved at 0.0% [Kuraray Co., Ltd., Kuraray Poval PVA]
-217C] was mixed with 112 g, and the number of revolutions was changed using a homogenizer to emulsify and disperse at 20 ° C. Then
After adding 15.0 g of water and 0.50 g of tetraethylenepentamine to this emulsified dispersion while stirring, the emulsified dispersion is heated to 65 ° C. while stirring and reacted at that temperature for 3 hours while stirring. Finally, water was added to prepare an aqueous dispersion of microcapsules having a solid content of 22.0% as microcapsules. The solid content was determined by drying microcapsules obtained by filtering and separating a dispersion liquid having a predetermined mass, and
The average particle diameters of the microcapsules shown in Nos. 2 and 2 are obtained by measuring the particle size of the microcapsule aqueous dispersion with a particle size measuring instrument [Shimadzu Corporation
Made, laser diffraction type particle size distribution measuring device new product SALD-7
[000]] (solid content and average particle size in the following preparation method were also measured by the same measurement method).

Next, this microcapsule aqueous dispersion was filtered off, if necessary, and the microcapsules were thoroughly washed with water and then with methanol and then air-dried. To 5.0 g of the air-dried microcapsules, 45.0 g of a methyl ethyl ketone solution of polyvinyl butyral [Sekisui Chemical Co., Ltd., Eslec BL-5Z] having a solid content of 11.1%.
After addition and stirring, ultrasonic dispersion was performed to obtain a microcapsule dispersion liquid containing a silver saving agent.

(Preparation Method 2) 9.0 g of a silver saving agent (described in Tables 1 and 2) was dissolved in 17.0 g of ethyl acetate, and then isocyanate compound A [Takenate D110N manufactured by Mitsui Takeda Chemical Co., Ltd.] 20. 0 g and isocyanate compound B [manufactured by Nippon Polyurethane Industry Co., Ltd., Millionate M]
R400] was added in an amount of 2.0 g. Next, this solution was mixed with 42.0 g of an aqueous phthalated gelatin solution having a solid content of 8.0%,
The mixture was added to a mixed solution of 1.5 g of a sodium dodecylbenzenesulfonate aqueous solution having a solid content of 10.0%, and the mixture was emulsified and dispersed at 20 ° C. while changing the rotation speed using a homomixer. Then, after adding 15.0 g of water and 75.0 g of an aqueous solution of diethylenetriamine having a solid content of 3.0% to the emulsion dispersion,
This emulsified dispersion was heated to 65 ° C. with stirring, reacted at that temperature for 2 hours with stirring, and finally water was added to prepare a microcapsule aqueous dispersion having a solid content of 21% as microcapsules. .

Then, if necessary, the same procedure as in Preparation Method 1 was used to obtain a methylethylketone solvent dispersion liquid of microcapsules containing a silver-saving agent.

(Preparation Method 3) Methylene chloride 11.
11.0 g of a silver-saving agent (described in Tables 1 and 2) was dissolved in a mixed solution of 0 g and dicyclohexylmethane-4,4'-diisocyanate, and the mixture was heated to 30 ° C and heated to 30 ° C. 100 g of a warm polyvinyl alcohol aqueous solution having a solid content of 8.0% [Gosenol GM-14L manufactured by Nippon Synthetic Chemical Industry Co., Ltd.] was added, and the number of revolutions was changed using a homomixer to carry out emulsion dispersion at 30 ° C. Next, 40.0 g of water was added to this emulsified dispersion liquid, and the mixture was stirred while stirring.
The temperature was raised to 0 ° C., the reaction was carried out at that temperature for 10 hours, and finally water was added to prepare an aqueous dispersion of microcapsules having a solid content of 24% as microcapsules.

Then, if necessary, the same method as in Preparation Method 1 was used to obtain a methyl ethyl ketone solvent dispersion liquid of microcapsules containing a silver-saving agent.

(Preparation Method 4) 4.0 g of butyl acetate, 6.0 g of dibutyl phthalate and an isocyanate compound [Takenate D110N] manufactured by Mitsui Takeda Chemical Co., Ltd. 1
A silver saving agent (described in Tables 1 and 2) was added to 2.0 g of the mixed solution.
Was dissolved, and then an aqueous solution of polyvinyl alcohol having a solid content of 8.0% [manufactured by Nippon Synthetic Chemical Industry Co., Ltd., Gohsenol GM
-14 L] was added in an amount of 81.0 g. The solution was emulsified by irradiating the solution with ultrasonic waves for 0.5 seconds at 0.5 second intervals for 20 seconds including the rest time while stirring the solution. Add 2 to this solution with further stirring.
5.0 g of water was added, and the solution was irradiated with ultrasonic waves under the same conditions as above while further stirring. Further, 25.0 g of water was added to this solution while stirring, then this solution was heated to 60 ° C. while stirring, and reacted at that temperature for 2 hours while stirring, and finally water was added to form microcapsules. A microcapsule aqueous dispersion having a solid content of 18% was prepared.

Then, if necessary, the same procedure as in Preparation Method 1 was used to obtain a methyl ethyl ketone solvent dispersion of microcapsules containing a silver-saving agent.

(Preparation method 5) 1- (3,4-dimethylphenyl) -1-phenylethane 64.0 g, isocyanate compound [Sumitomo Bayer Urethane Co., Ltd., Sumidule PF] 20.0 g and ethyl acetate 20. 0 g was mixed, and 16.0 g of the silver-saving agent was dissolved in this with stirring. An aqueous solution of polyvinyl alcohol having a solid content of 5.0% [Kuraray Co., Ltd., Kuraray Poval PVA-217C] is added to this solution.
Was added at 81.0 g, and the number of revolutions was changed by using a homomixer at 20 ° C. for emulsion dispersion. Next, after adding 42.0 g of water and 8.0 g of diethylenetriamine to this emulsified dispersion, the mixture was heated to 75 ° C. with stirring, reacted at that temperature for 3 hours with stirring, and finally water was added to form microcapsules. A microcapsule aqueous dispersion having a solid content of 45% was prepared.

Then, if necessary, the same method as in Preparation Method 1 was used to obtain a methyl ethyl ketone solvent dispersion liquid of microcapsules containing a silver-saving agent.

[0181]

[Table 1]

[0182]

[Table 2]

In the table, CV-1 is ethoxymethylene malonitrile CV-2 is ethyl 3-ethoxy-2-cyanoacrylate CV-3 is ethyl 3-chloro-2-cyanoacrylate CV-4 is 3- (1H Ethyl-benzotriazol-1-yl) -2-cyanoacrylate MEK represents methyl ethyl ketone.

Example 1 << Preparation of Photothermographic Material >><Preparation of Backing Layer-Forming Coating Liquid> A backing layer-forming coating liquid was prepared according to the method described below.

While stirring 83 g of methyl ethyl ketone, cellulose acetate butyrate (manufactured by Eastman Chemical Co.,
CAB381-20) (8.42 g) and polyester resin (Toyobo Co., Ltd., Byron 280) 0.45 g were added and dissolved. To this dissolved liquid was added 1.03 g of infrared dye 1.

Separately, in 4.32 g of methanol, 0.64 g of a fluorochemical surfactant (Surflon S-381 (70% active ingredient) manufactured by Asahi Glass Co., Ltd.) and a fluorochemical surfactant (Dainippon Ink and Chemicals Co., Ltd.) (Made, Megafag F120K)
0.23 g was dissolved, the fluorine-based surfactant solution was added to the solution containing the infrared dye 1, and the mixture was sufficiently stirred until the infrared dye 1 was completely dissolved. Finally, 7.5 g of silica (manufactured by Fuji Silysia Chemical Ltd., Sylobic 4004) dispersed in methyl ethyl ketone with a dissolver type homogenizer at a concentration of 1% was diluted with methyl ethyl ketone to obtain an isocyanate compound having a solid content concentration of 20% by mass ( Nippon Polyurethane Industry Co., Ltd., Coronate C-
3041) and 1.78 g were sequentially added and stirred to prepare a backing layer forming coating liquid.

<Coating of backing layer> Then, with a blue dye (Cerres Blue RR-J, manufactured by Bayern Co., Ltd.), a visual transmission density (measured with a PDA-65 manufactured by Konica Corporation to three decimal places) 0 Thickness 15 colored to .157
Regarding a 5 μm biaxially stretched polyethylene terephthalate film, one side thereof was subjected to a batch type atmospheric pressure plasma processing apparatus (AP-I-H-340 manufactured by EC Chemicals Co., Ltd.), high frequency output was 4.5 kW, and frequency was 5 kHz,
Plasma treatment was performed for 5 seconds at a gas condition of 90%, 5%, and 5% by volume of argon, nitrogen, and hydrogen, respectively, and then the opposite surface was subjected to corona discharge treatment (4
0 W / m ² · min), and the backing layer forming coating liquid is applied to the corona discharge treated surface to give a dry film thickness of 3.50 μm.
Was coated by an extrusion coater so as to be, and then dried to form a backing layer.

<Preparation of Coating Solution for Forming Image-Forming Layer> (Preparation of Photosensitive Silver Halide Emulsion 1) 7.5 g of ossein gelatin having an average molecular weight of 100,000 and 10 mg of potassium bromide were dissolved in 900 ml of water. After adjusting the temperature to 35 ° C. and pH to 3.0, an aqueous solution 370 containing 74 g of silver nitrate
ml, and 370 ml of an aqueous solution containing potassium bromide and potassium iodide in a molar ratio of (98/2) equimolar to silver nitrate and iridium chloride at 1 × 10 ⁻⁴ mol per mol of silver, pA
It was added over 10 minutes by the controlled double jet method while maintaining the g of 7.7. Then 4-hydroxy-6
-Methyl-1,3,3a, 7-tetrazaindene 0.3
g, pH was adjusted to 5 with NaOH, the average particle size was 0.06 μm, the coefficient of variation of particle size was 12%, [1
[00] Cubic silver iodobromide grains having an area ratio of 87% were obtained. This emulsion was coagulated and sedimented using a gelatin coagulant and desalted, and then 0.1 g of phenoxyethanol was added thereto to adjust the pH to 5.
9, pAg 7.5 was adjusted to obtain a photosensitive silver halide emulsion 1.

(Preparation of powdered organic silver salt A) Separately, 4720
11 ml of behenic acid and 8 of arachidic acid in ml of pure water.
3.8 g and 54.9 g of stearic acid were dissolved at 80 ° C. Next, 540.2 ml of a 1.5 mol / L sodium hydroxide aqueous solution was added while stirring at high speed, and concentrated nitric acid 6.
After adding 9 ml, the mixture was cooled to 55 ° C. to obtain a fatty acid sodium solution.

The temperature of the fatty acid sodium solution was adjusted to 55
The photosensitive silver halide emulsion 1 prepared above (containing 0.038 mol of silver) and 450 ml of pure water were added while the temperature was kept at 0 ° C., and the mixture was stirred for 5 minutes. Next, 1 mol / L silver nitrate solution 7
60.6 ml was added over 2 minutes, the mixture was stirred for another 20 minutes, and water-soluble salts were removed by filtration. After that, washing with deionized water and filtration were repeated until the electric conductivity of the filtrate reached 2 μS / cm, centrifugal dehydration was carried out, and then hot air drying was carried out at 37 ° C. until there was no loss of mass, and the powdered organic silver salt was used. I got A.

(Preparation of Photosensitive Emulsion Dispersion) Next, 14.57 g of polyvinyl butyral resin (S-REC BL-5Z, manufactured by Sekisui Chemical Co., Ltd.) was added to methyl ethyl ketone 1
It was dissolved in 457 g, and while stirring with a dissolver type homogenizer, 500 g of the above-prepared powdered organic silver salt A was gradually added and thoroughly mixed. After that, a zirconia bead having a particle diameter of 1 mm (manufactured by Toray Industries, Inc.) was filled with 80%, and a peripheral speed of 1 was obtained by a media disperser (manufactured by Gettzmann).
Dispersion was carried out at a residence time of 3 m in the mill for 0.5 minutes to prepare a photosensitive emulsion dispersion.

(Preparation of coating liquid for forming image forming layer) 50 g of the above photosensitive emulsion dispersion and 10.0 g of methyl ethyl ketone.
And keep it at 18 ℃ while stirring,
0.320 g of the methanol solution (11.2%) was added and stirred for 1 hour. Further, 0.212 g of a methanol solution of calcium bromide (11.2%) was added and stirred for 20 minutes, and then 1.00 g of methanol was separately added to 1.00 g.
0.343 g of a solution prepared by dissolving dibenzo-18-crown-6 in Example 3 and 0.31 g of potassium acetate was added and stirred for 10 minutes. Next, the dye solution 1 shown below was added to 4.395.
After adding g and stirring for 60 minutes, the temperature was lowered to 13 ° C. and stirring was continued for another 50 minutes.

<Dye Solution 1> Infrared sensitizing dye 1 0.0086 g Benzoic acid derivative 1 2.476 g Methyl ethyl ketone 25.00 g While keeping the solution to which this dye solution was added at 13 ° C.,
0.766 g of a methanol solution (0.50%) of a thiuronium compound (Exemplified Compound T-7) was added and stirred for 5 minutes, and then polyvinyl butyral resin (Sekisui Chemical Co., Ltd., S-REC BL-5Z) was added thereto. 0.29 g and 0.304 g of tetrachlorophthalic acid were sequentially added and sufficiently dissolved with stirring.

To this solution, 2.261 g, 13.543 g, 3.491 g of the following additive solutions 1, 2, 3, and 4 separately dissolved in methyl ethyl ketone were obtained.
While successively stirring 4.597 g, finally, the microcapsule dispersion liquid encapsulating the silver-saving agent shown in Table 3 was added and stirred to prepare an image forming layer forming coating liquid.

In addition, in addition, the image forming layer forming coating liquid 1, in which the microcapsules containing the silver saving agent are not added,
In place of the microcapsule dispersion liquid containing a silver saving agent, ethyl 3-ethoxy-2-cyanoacrylate (CV) which is a silver saving agent not included in a microcapsule is used.
An image-forming layer-forming coating liquid prepared by using -2) was prepared in the same manner.

[0196]   <Additive solution 1>   Isocyanate compound (Sumitomo Bayern Urethane Co., Ltd.     Sumidur N-3300) 5.630g   p-Toluenethiosulfonate potassium 0.415 g   Methyl ethyl ketone 20.00 g   <Additive solution 2>   1,1-bis (2-hydroxy-3,5-dimethylphenyl)     -3,5,5-Trimethylhexane 6.070 g   4-methylphthalic acid 0.401 g   Infrared dye 1 0.0262g   Methyl ethyl ketone 20.00 g   <Additive solution 3>   Trihalomethyl group-containing compound (Exemplary compound P-15) 1.543 g   2-phenyl-4,6-bis (trichloromethyl) -s-triazine                                                         1.407g   Methyl ethyl ketone 10.01g   <Additive solution 4>   Phthalazine 1.420 g   Methyl ethyl ketone 20.00 g

[0197]

[Chemical formula 24]

<Preparation of Protective Layer Forming Coating Liquid> While stirring in 86.5 g of methyl ethyl ketone, 10.05 g of cellulose acetate butyrate (manufactured by Eastman Chemical Company, CAB1) was used.
71-15), 0.013 g of benzotriazole, fluorinated activator (Surflon KH40 manufactured by Asahi Glass Co., Ltd.)
0.10 g was added and dissolved.

Separately, a solution of 55.0 g of cellulose acetate butyrate (manufactured by Eastman Chemical Company, CAB171-15) dissolved in methyl ethyl ketone with a solid content of 15% was added to silica (manufactured by Fuji Silysia Chemical Ltd., Sylysia 320).
Of 5.0 g was added and dispersed by a media disperser filled with zirconia beads to prepare a silica dispersion. Next, 3.0 g of the silica dispersion liquid was added while stirring the resin solution in which the above-mentioned benzotriazole was dissolved, followed by ultrasonic dispersion to prepare a protective layer forming coating liquid.

<Coating on Image Forming Layer Surface Side> The wet film thickness of each of the image forming layer forming coating liquids 1 to 34 prepared by the above-mentioned method was variously changed so that the coating silver amount shown in Table 3 was obtained. The above-prepared protective layer-forming coating solution was applied to form a multilayer coating using an extrusion coater, and then dried with hot air at 70 ° C. to prepare a photothermographic material. The thickness of the protective layer after drying was adjusted to be 2.35 ± 0.15 μm.

[0201]

[Table 3]

<Image Recording Method and Image Evaluation><ImageRecording> Each of the above-prepared photothermographic materials was stored for 72 hours at room temperature (temperature and humidity: 23 ° C. and 55%, respectively) under light shielding. Temperature and humidity are 50 each
What was stored for 72 hours in a thermostat at 55 ° C. and 55% was used, from the image forming layer side of each photothermographic material,
By using an exposure machine that uses a semiconductor laser in the longitudinal multimode having a wavelength of 800 to 820 nm in high frequency superposition as an exposure source,
Exposure is performed by laser scanning while changing the exposure amount, and then an automatic developing machine having a heat drum is used to bring the protective layer of the photothermographic material into contact with the drum surface at 127 ° C. for 13.6 seconds. The thermal development treatment was performed under the developing conditions of No. 1 to produce a photothermographic material that had been subjected to the thermal development treatment.

In the laser scanning exposure, the angle between the exposure surface of the photothermographic material and the exposure laser beam is 75 degrees, the laser spot diameter on the protective layer surface is 100 μm in the main scanning direction and 75 μm in the sub-scanning direction, and the laser scanning is performed. Pitch is 10 in the main scanning direction
0 μm, 75 μm in the sub-scanning direction, JIS K6
An automatic developing machine having a heat drum having a surface rubber hardness of 70 defined by 253 type A was used.

<Image Evaluation> The sensitivity, maximum density and image fog density of each image obtained by the above-mentioned exposure and heat development processing were evaluated according to the following criteria.

(Measurement of Sensitivity and Gamma) The formed silver image was analyzed by visual transmission density (PDA manufactured by Konica Corp., PDA).
-65: 3 digits to the right of the decimal point), the reciprocal of the exposure dose that gives a density 1.0 higher than that of the unexposed area was determined, and this was defined as the sensitivity. The photothermographic material Sample to which no alkoxysilane compound was added was used. No. The sensitivity of the sample stored at room temperature of 1 was evaluated as a relative value with 100 being the sensitivity. The exposure amount at which the density becomes +1.0 in the unexposed area is
At least three points were measured between the concentrations of 0.7 to +1.2, and the linear regression was obtained. Gamma is represented by the tangent of density 0.1 and 3.0.

(Measurement of Maximum Density: Dmax) The visual transmission density (PDA-65, manufactured by Konica Corporation, PDA-65: 2 digits after the decimal point) in the maximum exposed portion of the exposed portion was measured at 10 points, and the average value was determined as the maximum density. It was evaluated as (Dmax).

(Measurement of Fogging Density) The visual transmission density (PDA-65 manufactured by Konica Corporation, 3 digits after the decimal point) of the unexposed portion was measured at 10 points, and the average value was evaluated as the fogging density (Dmin). did.

Table 4 shows the results obtained as described above.

[0209]

[Table 4]

As is clear from Table 4, the sample using the microphone capsule containing the silver-saving agent according to the present invention in the image forming layer can save silver as compared with Comparative Example and is excessively hardened. That is, it can be seen that high Dmax and low fog density are obtained, and even after being stored at high temperature, gradation, Dmax, and fog density fluctuation are small and storage stability is excellent.

Example 2 << Preparation of Photothermographic Material >> An image forming layer-forming coating solution was prepared according to the method described below, and the same procedure as in Example 1 was carried out with the following image forming layer forming coating solution. The protective layer-forming coating solution described in Example 1 was applied in multiple layers to prepare a photothermographic material. The amount of silver applied per unit area was as shown in Table 5, and the thickness of the protective layer after drying was set to 2.35 ± 0.15 μm.

<Preparation of Coating Solution for Forming Image Forming Layer> Example 1
50 g of a photosensitive emulsion dispersion and 10.0 g of methyl ethyl ketone prepared by the same method as above were mixed and stirred with stirring 21
It was kept warm at ℃. Methanol solution of antifoggant 1 (1
1.2%) was added to 0.320 g, and the mixture was stirred for 1 hour. Further, a solution of calcium bromide in methanol (11.2%) was added to 0.1%.
424 g was added and the mixture was stirred for 20 minutes, and then, 0.343 g of a solution prepared by dissolving 1.00 g of dibenzo-18-crown-6 and 0.31 g of potassium acetate in 10.0 g of methanol was added and added to 10 g. Stir for minutes.

Next, the dye solution 2 shown below was added to 2.622.
After adding g and stirring for 1 hour, the temperature was lowered to 13 ° C. and stirring was continued for 30 minutes.

(Dye solution 2) Infrared sensitizing dye 1 0.0192 g Benzoic acid derivative 1 2.779 g 2-Chloro-benzoic acid 1.488 g 5-Methyl-2-mercaptobenzimidazole 0.365 g Methyl ethyl ketone 25.205 g Above Polyvinyl butyral resin (Sekisui Chemical Co., Ltd.) while keeping the temperature of the solution containing the dye solution 2 at 13 ° C
Manufactured by S-REC BL-5Z) and 13.04 g of tetrachlorophthalic acid were sequentially added, and sufficiently dissolved with stirring.

2.261 g, 13.543 g, 5.732 g, and 4.263 g of the following additive solutions 5, 6, 7, and 8 respectively dissolved in methyl ethyl ketone were added to this solution.
597 g was sequentially added with stirring, and then the microcapsule dispersion liquid containing the silver-saving agent shown in Table 5 was added in an amount shown in Table 5 and stirred to prepare an image forming layer forming coating liquid.

In addition, instead of the microcapsule dispersion containing the silver saving agent and the image forming layer forming coating solution and the microcapsule dispersion containing the silver saving agent, microcapsules were used instead. An image forming layer forming coating solution using ethyl 3-ethoxy-2-cyanoacrylate (CV-2), which is a silver saving agent not included in Example 1, was prepared by the same method.

(Additive Solution 5) Isocyanate Compound (Sumitomo Bayern Urethane Co., Ltd., Sumidule N-3300) 5.630 g Methyl ethyl ketone 20.00 g (Additive Solution 6) 1,1-bis (2-hydroxy-3) , 5-Dimethylphenyl) -3,5,5-trimethylhexane 6.070 g 4-methylphthalic acid 0.401 g Infrared dye 1 0.0262 g Methyl ethyl ketone 20.00 g (Additive solution 7) Trihalomethyl group-containing compound 1 (exemplification) Compound P-15) 1.407 g Methyl ethyl ketone 20.00 g (Additive solution 8) Phthalazine 1.420 g Methyl ethyl ketone 20.00 g <Coating on image forming layer surface side> The image forming layer forming coating solution prepared above was used in Example 1. The backing layer prepared in Example 1 has been coated by the method described. On the lifting member, to prepare a photothermographic material by multi-layer coating and a protective layer formed coating described in Example 1 and the image forming layer forming coating liquid. Upon application, the amount of silver applied per unit area of the image forming layer was adjusted to be the amount shown in Table 5, and the thickness of the protective layer after drying was 2.
It was set to 35 ± 0.15 μm.

<Image recording method and image evaluation><Imagerecording> Image recording and heat development were carried out in the same manner as in Example 1 to prepare a heat-developable photosensitive material.

[0219]

[Table 5]

<Image Evaluation> The image was evaluated according to the same evaluation criteria as in Example 1, and the obtained results are shown in Table 6. Note that the sensitivity is Sample N for the photothermographic material prepared in Example 1.
o. The relative sensitivity was displayed with the sensitivity of 1 as 100.

[0221]

[Table 6]

As is clear from Table 6, the sample using the microphone capsule containing the silver-saving agent according to the present invention in the image forming layer can save silver as compared with the comparative example and is excessively hardened. That is, it can be seen that high Dmax and low fog density are obtained, and even after being stored at high temperature, gradation, Dmax, and fog density fluctuation are small and storage stability is excellent.

Example 3 << Preparation of Photothermographic Material >> A photothermographic material was prepared by the following method.

<Preparation of Coating Liquid for Forming Intermediate Layer> 5.0 g of crosslinked acrylic resin particles (MX-180 manufactured by Soken Kagaku Co., Ltd.) was stirred and dispersed in 45.0 g of methyl ethyl ketone with a dissolver to obtain a filler dispersion. Prepared.

2.0 g of this filler dispersion was dissolved in a mixed solvent of methyl ethyl ketone / toluene = 1/1 to obtain a polyurethane resin solution having a solid content of 30% (Toyobo Co., Ltd.).
Manufactured by Byron UR-8300) 32.7 g with stirring, and then the microcapsule dispersion liquid containing the silver-saving agent shown in Table 7 is added and stirred to form an intermediate layer forming layer. A coating liquid was prepared.

In addition, in addition, an intermediate layer forming coating liquid containing no microcapsule dispersion liquid containing a silver saving agent,
In place of the microcapsules containing the silver-saving agent, an intermediate layer-forming coating solution using ethoxymethylenemalonitrile (Compound 1) which is the silver-saving agent not included in the microcapsules is prepared by the same method. did.

<Coating of Coating Liquid for Forming Intermediate Layer> Next, a backing layer having a thickness of 175 was formed in the same manner as in Example 1.
Corona discharge treatment (80W / m) on the opposite side of the backing layer of the biaxially stretched polyethylene terephthalate film of μm
² min.) And coating each intermediate layer forming coating solution on this corona discharge treated surface using an extrusion coater.
It was dried with warm air at ℃ to form an intermediate layer having a coating weight of 1.8 g / m ² .

<Preparation of Coating Solution for Forming Image Forming Layer> Example 1
Image forming layer forming coating liquid No. Prepared 2.

<Coating of Image Forming Layer and Protective Layer> Each of the image forming layer forming coating liquids in Example 1 was prepared on the above-prepared intermediate layer-coated support in the combinations shown in Table 7. The protective layer-forming coating solution described above was applied in multiple layers using an extrusion coater, and then dried with hot air at 70 ° C. to prepare a photothermographic material. The amount of silver applied per unit area was adjusted to be the amount shown in Table 7, and the thickness of the protective layer was 2.35 ± 0.
It was set to 15 μm.

[0230]

[Table 7]

<Image Recording Method and Image Evaluation><ImageRecording> Each of the photothermographic materials prepared above was exposed to light at room temperature (temperature and humidity were 23 ° C. and 55%, respectively) for 7 days.
After storing for 2 hours, the exposure amount is changed by an exposure device using a semiconductor laser in the longitudinal multimode mode having a wavelength of 800 to 820 nm as an exposure source by high-frequency superposition from the image forming layer side of each photothermographic material. Exposure by scanning,
Then, using an automatic developing machine having a heat drum, a heat developing treatment is performed under a developing condition of 127 ° C. for 13.6 seconds so that the protective layer of the photothermographic material is in contact with the drum surface. A developed photothermographic material was prepared.

In the laser scanning exposure, the angle between the exposure surface of the photothermographic material and the exposure laser light is 75 degrees, the laser spot diameter on the protective layer surface is 100 μm in the main scanning direction and 75 μm in the sub scanning direction, and the laser scanning is performed. Pitch is 10 in the main scanning direction
0 μm, 75 μm in the sub-scanning direction, JIS K6
An automatic developing machine having a heat drum having a surface rubber hardness of 70 defined by 253 type A was used.

<Evaluation of Image> According to the method described in Example 1, the sensitivity, Dmax and Dmin were measured, and the film attached was evaluated by the method described below. Note that the sensitivity is Sample N for the photothermographic material prepared in Example 1.
o. The relative sensitivity was displayed with the sensitivity of 1 as 100.

<Evaluation with Film> Using a photographic cutter (manufactured by Konica), room temperature (temperature and humidity were 23 ° C. and 5 ° C., respectively).
(5%) for 72 hours so that the protective layer surface of the photothermographic material is on the upper side and the position 5 mm away from the cutting site is uniformly fixed, and then the cutting speed is changed in two steps to perform heat development. The cut surface of the light-sensitive material was observed with a microscope over a width of 150 mm, and the maximum value of the distance (mm) from the cut edge to the portion where film peeling occurred was measured.

Table 8 shows the results obtained as described above.

[0236]

[Table 8]

As is clear from Table 8, the sample having the microcapsules containing the silver-saving agent according to the present invention in the intermediate layer can be silver-saving as compared with the comparative example and does not cause excessively high contrast. It can be seen that a high Dmax and a low fog density are obtained and the film-attached property is excellent.

Example 4 << Preparation of Photothermographic Material >> A photothermographic material was prepared by the following method.

<Preparation of coating liquid for forming intermediate layer> Water 25.0 g
5.0g silica particles [Fuji Silysia Chemical Ltd., Silysia 310] in a mixed solution of 20.0g of methanol and methanol.
Was dispersed by stirring with a dissolver to prepare a filler dispersion liquid, and 3.0 g of this filler dispersion liquid was used as an aqueous polyester dispersion having a solid content of 30% [Pesresin A- manufactured by Takamatsu Yushi Co., Ltd.].
210] 40.0 g, and then the microcapsules containing the silver-saving agent shown in Table 9 were added in the amounts shown in Table 9 and stirred to prepare a coating liquid for forming an intermediate layer.

In addition, instead of the intermediate layer forming coating liquid in which the microcapsules containing the silver-saving agent were not added, and the microcapsules containing the silver-saving agent, the microcapsules were not included. An intermediate layer forming coating solution using ethoxymethylene malonitrile (Compound 1) as a silver saving agent was prepared by the same method.

<Coating of Coating Liquid for Forming Intermediate Layer> Next, a backing layer having a thickness of 175 was formed in the same manner as in Example 1.
Corona discharge treatment (80W / m) on the opposite side of the backing layer of the biaxially stretched polyethylene terephthalate film of μm
² min.) And coating each intermediate layer forming coating solution on this corona discharge treated surface using an extrusion coater.
The coated layer was dried with warm air at ℃ to form an intermediate layer having a coating weight of 1.3 g / m ² .

<Preparation of Coating Solution for Forming Image Forming Layer> Example 2
Image forming layer forming coating liquid No. I prepared 36.

<Coating of Image Forming Layer and Protective Layer> Each of the image forming layer forming coating solutions described in Example 1 was formed on the above-prepared intermediate layer coated support in the combinations shown in Table 9. The protective layer-forming coating solution described above was applied in multiple layers using an extrusion coater, and then dried with hot air at 70 ° C. to prepare a photothermographic material. The amount of silver applied per unit area was adjusted to be the amount shown in Table 9, and the thickness of the protective layer was 2.35 ± 0.
It was set to 15 μm.

[0244]

[Table 9]

<Image recording method and image evaluation><Imagerecording> Each of the photothermographic materials prepared above was exposed to light at room temperature (temperature and humidity of 23 ° C. and 55%, respectively) for 7 days.
After storing for 2 hours, the exposure amount is changed by an exposure device using a longitudinal multimode semiconductor laser having a wavelength of 800 to 820 nm as an exposure source by superposing a high frequency from the image forming layer side of each photothermographic material. Exposure by scanning,
Then, by using an automatic developing machine having a heat drum, the heat developing treatment is performed under a developing condition of 127 ° C. for 13.6 seconds so that the protective layer of the photothermographic material is in contact with the surface of the drum. A developed photothermographic material was prepared.

In the laser scanning exposure, the angle between the exposure surface of the photothermographic material and the exposure laser beam is 75 °, the laser spot diameter on the protective layer surface is 100 μm in the main scanning direction and 75 μm in the sub-scanning direction. Pitch is 10 in the main scanning direction
0 μm, 75 μm in the sub-scanning direction, JIS K6
An automatic developing machine having a heat drum having a surface rubber hardness of 70 defined by 253 type A was used.

<Evaluation of Image> According to the method described in Example 1, the sensitivity, Dmax and Dmin were measured, and the film attached was evaluated by the method described below. Note that the sensitivity is Sample N for the photothermographic material prepared in Example 1.
o. The relative sensitivity was displayed with the sensitivity of 1 as 100.

<Evaluation with Film> Using a photo cutter (manufactured by Konica Corporation), room temperature (temperature and humidity were 23 ° C. and 5 ° C., respectively).
(5%) for 72 hours so that the protective layer surface of the photothermographic material is on the upper side and the position 5 mm away from the cutting site is uniformly fixed, and then the cutting speed is changed in two steps to perform heat development. The cut surface of the light-sensitive material was observed with a microscope over a width of 150 mm, and the maximum value of the distance (mm) from the cut edge to the portion where film peeling occurred was measured.

Table 10 shows the results obtained as described above.

[0250]

[Table 10]

As is clear from Table 10, the sample having the microcapsules containing the silver-saving agent according to the present invention in the intermediate layer can be silver-saving as compared with the comparative example, and does not cause excessively high contrast. It can be seen that a high Dmax and a low fog density are obtained and the film-attached property is excellent.

Example 5 The same as Example 1 except that the photothermographic materials shown in Table 11 were imagewise exposed by the following image recording methods 1 to 4 in the photothermographic materials produced in Examples 1 to 4. An image was formed by heat development at 127 ° C. for 13.6 seconds using an automatic processor. The interference fringes of the obtained image were evaluated by sensory evaluation and density measurement (ΔD) according to the following criteria. The results obtained are shown in Table 11. The exposure amount is the same as in Example 1.
The exposure energy was adjusted to be the same as the exposure energy on the surface of the protective layer.

<Image recording method 1> From the protective layer side of the photothermographic material, exposure by laser scanning was applied by an exposure device using a semiconductor laser having a wavelength of 820 nm as an exposure source. At this time, the angle between the exposure surface of the photothermographic material and the exposure laser light is set to 9
Image exposure was performed by setting it to 0 degree.

<Image recording method 2> From the protective layer side of the photothermographic material, exposure by laser scanning was applied by an exposure device using a semiconductor laser having a wavelength of 820 nm as an exposure source. At this time, the angle between the exposure surface of the photothermographic material and the exposure laser beam is set to 7
Image exposure was performed at 0 degree.

<Image recording method 3> From the protective layer surface side of the photothermographic material, exposure by laser scanning is applied by an exposure device using a semiconductor laser in the longitudinal multimode having a wavelength of 800 to 820 nm as an exposure source by high frequency superposition. It was At this time,
Image exposure was performed by setting the angle between the exposed surface of the photothermographic material and the exposure laser beam to be 90 degrees.

<Image recording method 4> From the protective layer side of the photothermographic material, two semiconductor lasers having a wavelength of 820 nm are used as exposure sources, and two laser beams emitted at the same time are deflected and scanned by a polygon mirror to form an fθ lens. The exposure was carried out by laser scanning using an exposing machine adapted to focus the light on the photothermographic material. At this time, image exposure was performed by setting the angle of the exposure laser beam to the exposure surface of the photothermographic material to one laser beam of 85 degrees and the other to 95 degrees. The energy intensity on the exposed surface of each laser beam was the same, and the energy intensity was 1/2 of the intensity of the image recording method 1.

(Sensory evaluation) The transmission density was 1.80 ± 0.1.
An image that has been exposed and heat-developed so that it has a brightness of 5 has a brightness of 1
The sample was placed on 0000 Schaukasten, the degree of occurrence of interference fringes was ranked as shown below, and sensory evaluation was performed.

4: No interference fringes are observed 3: Very slight interference fringes are observed 2: Partial clear interference fringes are observed 1: Clear interference fringes are observed (density measurement: ΔD) If the interference fringe pattern is clear by scanning and measuring the density of the image area using a densitometer that can narrow the slit aperture, it is quantitatively evaluated as the difference in transmission density between the bright and dark stripes. You can do it. Therefore, the image that was exposed and heat-developed so that the transmission density was 1.80 ± 0.15 was measured with a microdensitometer (Konica Microdensitometer PDM-7 type BR) manufactured by Konica Corporation. Five points were measured at intervals of 25 μm and a measurement length of 20 mm (total number of measurement points was 4000 points), and the sensory evaluation results described above and the difference ΔD in concentration were associated. The smaller ΔD indicates that interference fringes are less likely to occur.

[0259] ΔD = (maximum concentration in measurement point) − (minimum concentration in measurement point)

[0260]

[Table 11]

As is clear from Table 11, by using the image recording method defined in any one of claims 9 to 12 with respect to the photothermographic material of the present invention, an excellent image with less occurrence of interference fringes can be obtained. I was able to get it.

[0262]

INDUSTRIAL APPLICABILITY According to the present invention, heat development containing a silver-saving agent having excellent storage stability, excellent gradation, high maximum density, low fog, and prevention of interference fringes. A photosensitive material and a suitable image recording method using the photothermographic material can be provided.

Claims (12)

[Claims] 1. A backing layer is provided on one side of a support, and at least an organic silver salt, a photosensitive silver halide, a reducing agent and a silver saving agent are contained on the side of the support opposite to the backing layer. A photothermographic material comprising an image forming layer and a protective layer laminated in this order, wherein the silver saving agent is encapsulated in microcapsules. 2. The photothermographic material according to claim 1, wherein the microcapsules containing the silver-saving agent are heat-responsive microcapsules. 3. The average particle size of the microcapsules is 0.2.
The photothermographic material according to claim 1 or 2, wherein the photothermographic material has a thickness of 0 to 2.0 µm. 4. The wall material of the microcapsule is made of polyurethane or polyurea.
4. The photothermographic material according to any one of 3 above. 5. A support having a backing layer on one side thereof, and an intermediate layer containing at least a silver-saving agent on the side opposite to the backing layer of the support, an organic silver salt, a photosensitive silver halide, A photothermographic material comprising an image forming layer containing a reducing agent and a protective layer, which are laminated in this order, wherein the silver saving agent is encapsulated in microcapsules. 6. The photothermographic material according to claim 5, wherein the microcapsules containing the silver-saving agent are heat-responsive microcapsules. 7. The average particle size of the microcapsules is 0.2.
7. The photothermographic material according to claim 5, wherein the photothermographic material has a thickness of 0 to 2.0 .mu.m. 8. The microcapsule wall material is made of polyurethane or polyurea.
8. The photothermographic material according to any one of 7 above. 9. Scanning exposure is performed on the photothermographic material according to claim 1 by using a laser in which an angle between an exposure surface and laser light is not substantially perpendicular. An image recording method characterized by. 10. An image recording method, wherein the photothermographic material according to claim 1 is subjected to scanning exposure by using a longitudinal multi-laser having an exposure wavelength which is not single. 11. An image recording method, wherein the photothermographic material according to claim 1 is scanned and exposed by using two or more lasers. 12. The wavelength of a laser used for scanning exposure is 7
The image recording method according to any one of claims 9 to 11, wherein the image recording method is in a range of 00 to 1200 nm.