JPH0658535B2 - Photosensitive microcapsule and photosensitive material - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a photosensitive microcapsule and a photosensitive material using the same.

BACKGROUND OF THE INVENTION A light-sensitive material used in a method of forming an image by polymerizing a polymerizable compound by the action of a reducing agent in a portion where a latent image of silver halide is formed is disclosed in JP-B-45-1114.
No. 9, No. 47-20741, No. 49-10697,
The method is described in the image forming methods described in JP-A Nos. 57-138632 and 58-169143.

The inventors of the present invention tried to improve the above-mentioned image forming method and invented a method capable of forming a high molecular compound by a dry process, and the present invention has been applied for a patent (Japanese Patent Application No. 59-
191353). This method uses a recording material (photosensitive material) in which a photosensitive layer comprising a photosensitive silver salt (silver halide), a reducing agent, a crosslinkable compound (polymerizable compound) and a binder is carried on a support. Is.

The above image forming method is a method of polymerizing the polymerizable compound in the portion where the latent image of silver halide is formed. The present inventors have further invented a method capable of polymerizing a polymerizable compound in a portion where a latent image of silver halide is not formed, and this invention has already been applied for a patent (Japanese Patent Application No. 60-
210657). This method, by heating,
A reducing agent is caused to act on the portion where the latent image of silver halide is formed to suppress the polymerization of the polymerizable compound, and at the same time, the thermal polymerization initiator is used to accelerate the polymerization of other portions.

One of light-sensitive materials that can be used in these image forming methods is one having a constitution in which silver halide is present in oil droplets (or microcapsules) of a polymerizable compound (Japanese Patent Application No. 60-261888). Specification). The light-sensitive material having the above-mentioned structure has an advantage that the polymerization accelerating reaction (or polymerization suppressing reaction) of the polymerizable compound in the portion where the latent image of silver halide is formed smoothly proceeds.

[Summary of the Invention] The present inventor has conducted extensive research for the purpose of providing excellent photosensitive microcapsules that can be used in the production of photosensitive materials.

The object of the present invention is to provide photosensitive microcapsules which are very sensitive.

The present invention is a photosensitive microcapsule containing silver halide, wherein at least 70% of the total amount of silver halide contained in the microcapsule is contained in the wall material constituting the outer shell of the microcapsule. And a core material of the microcapsule contains a polymerizable compound.

The photosensitive microcapsules can be preferably used in a photosensitive material having a photosensitive layer containing a photosensitive microcapsule and a reducing agent on a support.

EFFECTS OF THE INVENTION The photosensitive microcapsules of the present invention are characterized by using a wall material containing silver halide as an outer shell.

The microcapsules use silver halide as an optical sensor, and have silver halide in the outermost shell, which is the most preferable in terms of utilization efficiency of light, and therefore have extremely high sensitivity to light.

Further, as a method of using the above-mentioned microcapsules, when a method of rupturing uncured microcapsules to release a core substance containing a polymerizable compound or the like is used, the release product may contain silver halide. rare. Therefore, it is easy to recover expensive silver, and the emission does not generate silver due to light to cause color turbidity.

The above effects are extremely advantageous especially when the photosensitive microcapsules are used as a photosensitive material.

Further, in the photosensitive material using the photosensitive microcapsules of the present invention, since the silver halide and the polymerizable compound are in close proximity to each other, the polymerization accelerating reaction of the polymerizable compound in the portion where the latent image of silver halide is formed is generated. (Or polymerization inhibition reaction)
Smoothly progresses, and the contrast between the portion where the latent image is formed and the portion where the latent image is not formed is improved. Therefore, the photosensitive material using the photosensitive microcapsules of the present invention can obtain an image having excellent sharpness.

DETAILED DESCRIPTION OF THE INVENTION The photosensitive microcapsule of the present invention is composed of a silver halide, a wall material, and a core substance containing a polymerizable compound (the core substance may be only the polymerizable compound).

As the silver halide in the present invention, a silver halide known in the photographic art can be used. Any of silver chloride, silver bromide, silver iodide or silver chlorobromide, silver chloroiodide, silver iodobromide and silver chloroiodobromide can be used in the photosensitive microcapsules of the present invention. The halogen composition of the silver halide grains may be uniform or non-uniform on the surface and inside. In the present invention, the average grain size of the silver halide grains is preferably 0.001 μm to 10 μm, and particularly preferably 0.001 μm to 5 μm. Two or more kinds of silver halides having different crystal habits, halogen compositions, grain sizes and the like can be used in combination.

The wall material constituting the outer shell of the photosensitive microcapsule of the present invention is not particularly limited, and a substance used for known microcapsules (generally polymers) can be used. For examples of multi-wall materials and known microcapsule technology that can be used in the photosensitive microcapsules of the present invention, see US Pat.
Method using coacervation of hydrophilic wall forming material described in each specification; US Pat. No. 328715
No. 4 and British Patent No. 990443, and Japanese Patent Publication Nos. 38-19574, 42-446 and 42-711, the interfacial polymerization method; US Pat.
Methods by precipitation of the polymers described in US Pat. Nos. 4,18,250 and 3,660,304; US Pat. No. 37,966.
Method using the isocyanate-polyol wall material described in US Pat. No. 69; Method using the isocyanate wall material described in US Pat. No. 3,914,511; US Pat. No. 40
01140, 4087376 and 408
9802 Method using urea-formaldehyde type or urea formaldehyde-resylcinol type wall forming material described in each specification; Method using wall forming material such as melamine-formaldehyde resin and hydroxypropyl cellulose described in US Pat. No. 4,025,455. In situ method by polymerization of monomers described in JP-B-36-9163 and JP-A-51-9079; British Patent No. 9
Polymerization dispersion cooling method described in each specification of 27807 and 965074; spray drying method described in each specification of U.S. Pat. No. 3,111,407 and British patent No. 930422 can be mentioned. The method of microencapsulation is not limited to the above, but a method of forming a polymer film as an outer shell of the microcapsule after emulsifying a core substance containing a polymerizable compound is particularly preferable.

In the photosensitive microcapsule of the present invention, the above wall material constituting the outer shell contains silver halide, but the silver halide may be contained in the core substance. However,
At least 70% of the total amount of silver halide contained in the microcapsules is contained in the wall material. Preferably, 90% or more is contained in the wall material. The ratio of silver halide contained in the wall material can be easily measured by rupturing the uncured microcapsules to release the core substance and examining the silver halide content in the released product.

The polymerizable compound contained in the core material of the photosensitive microcapsule of the present invention is not particularly limited, and a known polymerizable compound can be used. As a method of using the photosensitive microcapsules or a photosensitive material using the same, when a polymerization treatment by heating is planned, a compound having a high boiling point (for example, a boiling point of 80 ° C. or higher) that is hard to volatilize during heating is used. Preferably. Further, the embodiment containing a color image-forming substance as an optional component described below is intended to immobilize the color image-forming substance by polymerization of the polymerizable compound. Therefore, the polymerizable compound has a plurality of polymerizable functional groups in the molecule. It is preferably a crosslinkable compound having a group.

The polymerizable compound used for the photosensitive microcapsules is
Generally, it is a compound having addition-polymerizability or ring-opening polymerizability. The compound having an addition-polymerizable group includes a compound having an ethylenically unsaturated group, and the compound having a ring-opening polymerizable group includes a compound having an epoxy group. A compound having an ethylenically unsaturated group is particularly preferable.

Examples of the compound having an ethylenically unsaturated group that can be used in the photosensitive microcapsules of the present invention include acrylic acid and salts thereof, acrylic acid esters, acrylamides, methacrylic acid and salts thereof, methacrylic acid esters and methacrylic acid. Examples thereof include amides, maleic anhydride, maleic acid esters, itaconic acid esters, styrenes, vinyl ethers, vinyl esters, N-vinyl heterocycles, allyl ethers, allyl esters and their derivatives.

Specific examples of the polymerizable compound that can be used in the present invention include acrylic acid esters such as n-butyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate, benzyl acrylate, furfuryl acrylate, ethoxyethoxyethyl acrylate, dicyclohexyloxy. Ethyl acrylate, nonylphenyloxyethyl acrylate, hexanediol diacrylate, butanediol diacrylate, neopentyl glycol diacrylate, trimethylolpropane triacrylate, pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate,
Examples thereof include polyoxyethylenated bispheninol A diacrylate, hydroxypolyether polyacrylate, polyester acrylate and polyurethane acrylate.

Other specific examples of methacrylic acid esters include methyl methacrylate, butyl methacrylate, ethylene glycol dimethacrylate, butanediol dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpropane trimethacrylate, pentaerythritol trimethacrylate, and pentaerythritol tetramethacrylate. Methacrylate and dimethacrylate of polyoxyalkylenated bisphenol A and the like can be mentioned.

The polymerizable compounds may be used alone or in combination of two or more. A substance obtained by introducing a polymerizable functional group such as a vinyl group or a vinylidene group into the chemical structure of a reducing agent or a color image forming substance which is an optional component described later can also be used as the polymerizable compound of the present invention.

In the photosensitive microcapsules of the present invention, the polymerizable compound is preferably used in the range of 0.05 to 1200% by weight based on silver halide. A more preferable range of use is 5 to 950% by weight.

The polymerizable compounds that can be used in the photosensitive microcapsules are described in the application specifications for a series of photosensitive materials described above and below.

Regarding the core material of the photosensitive microcapsule of the present invention,
There is no particular limitation except that the polymerizable compound is included. Further, the core substance may be composed only of a polymerizable compound. It should be noted that substances such as a solvent used at the time of production (particularly, microencapsulation treatment) may remain in the core substance.

The photosensitive microcapsule of the present invention can be used in various applications including the production of various photosensitive materials with the above-mentioned constitution, but as an optional component, a reducing agent, a color image-forming substance, a sensitizing dye, an organic compound. Silver salts, various image formation accelerators (eg, bases or base precursors, oils, surfactants, thermal solvents, etc.), thermal polymerization inhibitors, thermal polymerization initiators, development terminators, fluorescent whitening agents, anti-fading agents , Antihalation or irradiation dyes, matting agents, antismudge agents (for example, starch particles), plasticizers, water-releasing agents, binders and the like.

When the photosensitive microcapsules of the present invention are used in the production of a photosensitive material, each of the above components (excluding a part of the sensitizing dye etc.) is used as an optional component in the photosensitive layer constituting the photosensitive material. It may be present in the capsule or outside the microcapsule. Details of each of the above components will be described in the description of the photosensitive material using the photosensitive microcapsules of the present invention described later.

The photosensitive microcapsules of the present invention have an average particle size of 0.
5 to 50 μm is preferable and 1 to 25 μm
Is more preferable.

The photosensitive microcapsule of the present invention can be manufactured, for example, as described below.

Of the components constituting the photosensitive microcapsules, silver halide is preferably prepared as a silver halide emulsion. Various types of halogenated emulsions known in the photographic art are used, but there is no particular limitation on the production of the photosensitive microcapsules of the present invention. For example, the silver halide emulsion may be a surface latent image type in which a latent image is mainly formed on the surface of a grain, or an internal latent image type in which a latent image is formed inside the grain. A direct reversal emulsion in which an internal latent image type emulsion and a nucleating agent are combined can also be used. Internal latent image type emulsions suitable for this purpose are described in US Pat. No. 25922.
No. 50, No. 3761276, each specification and Japanese Patent Publication No. 5
No. 8-3534, JP-A No. 58-136641, and the like. Preferred nucleating agents to be combined with the above emulsions are U.S. Pat. Nos. 3,227,552, 42450.
No. 37, No. 4255511, No. 4266013
No. 4,276,364 and West German Published Patent (OL
S) No. 2635316.

There are various methods known in the photographic art for the preparation of silver halide emulsions, but there is no particular limitation regarding the production of the photosensitive microcapsules of the present invention. Silver halide emulsion,
It can be prepared by any known method such as acidic method, neutral method or ammonia method such as acidic method, neutral method or ammonia method. The reaction mode of the soluble silver salt and the soluble halogen salt may be a one-sided mixing method, a simultaneous mixing method, or a combination thereof. A back-mixing method in which grains are formed under conditions of excess silver ions and a controlled double-jet method in which pAg is kept constant can also be adopted. Further, in order to accelerate the grain growth, the addition concentration, the addition amount or the addition rate of the silver salt and the halogen salt to be added may be increased (JP-A-55-158124 and JP-A-55-1).
58124 and U.S. Pat. No. 3,650,757).

In the preparation of the above silver halide emulsion, it is preferable to use a hydrophilic colloid as the protective colloid. Examples of hydrophilic colloids are gelatin, gelatin derivatives, graft polymers of gelatin and other polymers, proteins such as albumin and casein; cellulose derivatives such as hydroxyethyl cellulose, carboxymethyl cellulose, cellulose sulfates, sodium alginate. , Sugar derivatives such as starch derivatives, and polyvinyl alcohol, polyvinyl alcohol partial acetal, poly-N
-A variety of synthetic hydrophilic polymeric substances such as single or copolymers such as vinylpyrrolidone, polyacrylic acid, polymethacrylic acid, polyacrylamide, polyvinylimidazole and polyvinylpyrazole can be mentioned. Of these, gelatin is preferred. As the gelatin, lime-processed gelatin, acid-processed gelatin or enzyme-processed gelatin may be used, and a hydrolyzed product or an enzymatically-decomposed product of gelatin may also be used.

The silver halide emulsion contains ammonia, an organic thioether derivative (see JP-B-47-386) and a sulfur-containing compound (see JP-A-53-144319) as a silver halide solvent in the step of forming silver halide grains.
Etc. can be used. Further, in the process of grain formation or physical ripening, a cadmium salt, a zinc salt, a lead salt, a thallium salt or the like may be allowed to coexist. Further, iridium chloride (III value or IV value) is used for the purpose of improving high illumination failure and low illumination failure.
Value), a water-soluble iridium salt such as ammonium hexachloroiridium salt, or a water-soluble rhodium salt such as rhodium chloride can be used.

Soluble salts may be removed from the silver halide emulsion after formation of a precipitate or after physical ripening. In this case, it can be carried out according to the Nudel washing method or the sedimentation method. The silver halide emulsion may be used without ripening, but it is usually chemically sensitized before use. In the emulsion for conventional type light-sensitive material, known sulfur sensitizing method, reduction sensitizing method, noble metal sensitizing method, or a sensitizing method using a sensitizing dye described in Japanese Patent Application No. 60-139746 is used alone or in combination. Can be used. These chemical sensitizations can also be carried out in the presence of a nitrogen-containing heterocyclic compound (JP-A-58-126526 and 58-2).
(See each publication of 15644).

A photosensitive composition in which a silver halide is contained in a polymerizable compound (or an oily solvent containing the polymerizable compound; hereinafter sometimes simply referred to as a polymerizable compound) using the silver halide emulsion as described above. Can be prepared. Further, in the preparation of the photosensitive composition, in addition to the silver halide emulsion,
It is also possible to use a dry silver halide powder produced by freeze-drying or the like. The photosensitive composition containing these silver halides can be obtained by stirring with a homogenizer, blender, mixer or other commonly used stirrer.

In the preparation of the photosensitive composition containing the above silver halide, the copolymer represented by the following formula is dissolved in the polymerizable compound.

In A _x B _y [the above formulas, A is a repeating unit derived from a hydrophilic monomer, B is a repeating unit derived from a hydrophobic monomer, and x and y constituting the polymer, respectively It means the numerical value showing the mol% of A and B in all the repeating units, and 5 ≦ x ≦ 95, 5 ≦ y ≦ 95, and x + y = 100].

The copolymer represented by the above formula has the function of easily and uniformly dispersing the above silver halide (including silver halide emulsion) or other various components in the polymerizable compound. Further, the above-mentioned copolymer also has a function of precipitating silver halide at the interface between the polymerizable compound (photosensitive composition) and the aqueous solvent in the microencapsulation treatment described later. Therefore, by using the above copolymer, the silver halide can be easily included in the wall material that constitutes the outer shell of the microcapsule.

The copolymer is preferably used in an amount of 0.01 to 5% by weight based on silver halide. More preferably, it is in the range of 0.05% by weight to 2% by weight.

Any component such as a reducing agent or a color image forming substance may be dissolved, emulsified or dispersed in the photosensitive composition. In addition, a substance necessary for the microencapsulation treatment (including a wall material) may be included in the photosensitive composition.

The photosensitive composition prepared as described above is used by emulsifying it in an aqueous solvent in the production of the photosensitive microcapsules of the present invention. A wall surface is formed on the droplets of the photosensitive composition by using any of the various microencapsulation treatments described above for the aqueous emulsion of the photosensitive composition.
In this emulsification treatment and microencapsulation treatment,
Due to the action of the above-described copolymer, silver halide is deposited at the interface between the photosensitive composition and the aqueous solvent, and the formed wall material contains silver halide.

Thus, the aqueous liquid containing the photosensitive microcapsules of the present invention can be obtained. Evaporating the solvent of the aqueous liquid,
Alternatively, the photosensitive microcapsules of the present invention can be separated by removing them by filtration or the like.

Regarding the method of using the photosensitive microcapsules of the present invention,
This will be described below.

The photosensitive microcapsule of the present invention can be used for various purposes by further encapsulating a specific substance. Although not particularly limited, a catalyst, an adhesive, a curing agent,
Organic substances, inorganic substances and the like used for oxidizers, plasticizers, polymer flocculants, rust preventives, antioxidants and the like can be contained in the inclusions in a solid or liquid state.

When a photosensitive material is produced using the photosensitive microcapsules of the present invention, the microcapsules are dispersed in a suitable solvent to prepare a coating solution. The aqueous liquid containing the photosensitive microcapsules obtained in the final stage of the production of the microcapsules described above can be used as it is for the preparation of the coating liquid. Other components added to the light-sensitive material such as a reducing agent may be added to this coating liquid. When the aqueous liquid containing the microcapsules is used as it is for the preparation of the coating liquid, each component of the light-sensitive material may be added before and after the microcapsulation process described above.

A photosensitive material can be easily produced by applying the coating solution prepared as described above onto various supports described below and drying. The application of the coating solution onto the support can be easily carried out according to known techniques.

The photosensitive material using the photosensitive microcapsules of the present invention will be described below.

The above-mentioned light-sensitive material comprises a support and a light-sensitive layer containing the light-sensitive microcapsules of the present invention and a reducing agent.

The reducing agent that can be used in the photosensitive microcapsules and the photosensitive material has a function of reducing silver halide and / or a function of accelerating (or suppressing) the polymerization of the polymerizable compound. There are various kinds of substances as the reducing agent having the above function. Examples of the reducing agent include hydroquinones, catechols, p-aminophenols, p-phenylenediamines, 3-pyrazolidones, 3-aminopyrazoles, 4-amino-5-virazolones, 5-aminouracils, 4,5-Dihydroxy-6-aminopyrimidines, reductones, aminoreductones, o- or p-sulfonamidophenols, o- or p-
Sulfonamide naphthols, 2-sulfonamidoindanones, 4-sulfonamido-5-pyrazolones, 3
-Sulfonamide indoles, sulfonamide pyrazolobenzimidazoles, sulfonamide pyrazolotriazoles, α-sulfonamide ketones, hydrazines and the like.

Regarding various reducing agents having the above functions, Japanese Patent Application Nos. 60-22980, 60-29894 and 60-
68874, 60-226084, 60-22
No. 7527 and No. 60-227528. Regarding the reducing agent, "The Theory of the Photographic Process" 4th edition by T. James,
291-334 (1977), Research Disclosure, Vol. 170, June 1978, 17029.
Issue (pages 9 to 15) and Vol.176, 1987, 1
It is also described in February 17643 (pages 22 to 31). Also in the photosensitive microcapsule of the present invention and the photosensitive material using the same, the reducing agents (including those described as a developing agent or a hydrazine derivative) described in the above specifications and references can be effectively used. Therefore, the “reducing agent” in the present specification includes the reducing agents described in the above respective specifications and documents.

These reducing agents may be used alone or as a mixture of two or more reducing agents as described in the above specification. When two or more reducing agents are used in combination, the reducing agents may interact with each other by first promoting the reduction of silver halide (and / or organic silver salt) by so-called superadditivity. To cause polymerization of the polymerizable compound via an oxidation-reduction reaction with another reducing agent in which the oxidant of the first reducing agent generated by reduction of silver halide (and / or organic silver salt) coexists Etc. are possible. However, in actual use, it is difficult to specify which of the above actions because the above reactions can occur simultaneously.

In addition, as described above, the reducing agent may be contained in the microcapsules or may be present outside the microcapsules in the photosensitive material using the photosensitive microcapsules of the present invention. When the reducing agent is contained in the microcapsules, it is generally dissolved or dispersed in the core substance containing the polymerizable compound before use. Generally, the reducing agent is
It is preferable to include it in the microcapsules from the viewpoint of smooth progress of the reaction, but when the polymerization treatment by heating is planned as the method of using the photosensitive material, the reducing agent permeates into the microcapsules at the time of heating, There is no particular problem even if the reducing agent is present outside the microcapsules.

Specific examples of the reducing agent include pentadecylhydroquinone, 5-t-butylcatechol, p- (N, N-diethylamino) phenol, 1-phenyl-4-methyl-
4-hydroxymethyl-3-pyrazolidone, 1-phenyl-4-methyl-4-heptadecylcarbonyloxymethyl-3-pyrazolidone, 2- (N-phenylsulfamoyl) -4-hexadodecyloxy-5-octylphenol, 2- (N-phenylsulfamoyl) -4-
t-butyl-5-hexadodecyloxyphenol, 2
-(N-butylcarbamoyl) -4- (N-phenylsulfamoyl) naphthol, 2- (N-methyl-N-octadecylcarbamoyl) -4- (N-phenylsulfamoyl) naphthol, 1-acetyl-2 -Phenylhydrazine, 1-acetyl-2-{(p or o) -aminophenyl} hydrazine, 1-formyl-2-{(p or o) -aminophenyl} hydrazine, 1-acetyl-2-{(p or o) -methoxyphenyl} hydrazine, 1-lauroyl-2-{(p or o) -aminophenyl} hydrazine, 1-trityl-2- (2,6-dichloro-4-cyanophenyl) hydrazine, 1-trityl- 2-phenylhydrazine, 1-phenyl-2-
(2,4,6-trichlorophenyl) hydrazine, 1-
{2- (2,5-di-t-pentylphenoxy) butyroyl} -2-{(p or o) -aminophenyl} hydrazine, 1- {2- (2,5-di-t-pentylphenoxy) butyroyl } -2-{(p or o) -aminophenyl} hydrazine pentadecyl fluorocaprylate, 3-indazolinone, 1- (3,5-dichlorobenzoyl) -2-phenylhydrazine, 1-trityl-2
-[{2-N-butyl-N-octylsulfamoyl)
-4-Methanesulfonyl} phenyl] hydrazine, 1-
{4- (2,5-di-t-pentylphenoxy) butyroyl} -2-{(p or o) -methoxyphenyl} hydrazine, 1- (methoxycarbonylbenzohydryl)
-2-Phenylhydrazine, 1-formyl-2- [4-
{2- (2,4-di-t-pentylphenoxy) butylamido} phenyl] hydrazine, 1-acetyl-2-
[4- {2- (2,4-di-t-pentylphenoxy)
Butylamido} phenyl] hydrazine, 1-trityl-
2-[{2,6-dichloro-4- (N, N-di-2-ethylhexyl) carbamoyl} phenyl] hydrazine,
1- (methoxycarbonylbenzohydryl) -2-
(2,4-dichlorophenyl) hydrazine, and 1-
Examples thereof include trityl-2-[{2- (N-ethyl-N-octylsulfamoyl) -4-methanesulfonyl} phenyl] hydrazine.

In the photosensitive microcapsules and the light-sensitive material of the present invention, the reducing agent is in the range of 0.1 to 1500 mol% with respect to 1 mol of silver (including silver halide described below and an organic silver salt which is an optional component). Preference is given to using.

There is no particular limitation on the support of the photosensitive material using the photosensitive microcapsules of the present invention, but when heat development processing is planned as a method of using the photosensitive material, use a material that can withstand this processing temperature. Is preferred. As a material that can be used for the support, glass,
Paper, fine paper, coated paper, cast coated paper, synthetic paper, metal and its analogs, polyester, acetyl cellulose, cellulose ester, polyvinyl acetal, polystyrene, polycarbonate, polyethylene terephthalate, and other films, and resin materials and polyethylene and other polymers. The laminated paper can be mentioned.

The photosensitive material using the photosensitive microcapsules of the present invention,
Although a polymer image can be obtained by polymerizing the polymerizable compound with the above-described structure, a color image can be formed by including a color image forming substance as an optional component in the photosensitive layer. As described above, the color image-forming substance may be contained in the microcapsules or may be present outside the microcapsules in the photosensitive material using the photosensitive microcapsules of the present invention. It is preferably used by dissolving in a core substance containing a compound.

The color image-forming substance that can be used in the light-sensitive material is not particularly limited, and various types can be used. That is, a substance that is itself colored (dye or pigment), or energy that is colorless or pale but is external (heat, pressure, light irradiation, etc.) or another component (developing agent) A substance (color former) that develops a color upon contact is also included in the color image forming substance. When a plurality of the color image-forming substances are used, they are used in combination with at least three kinds of silver halide emulsions sensitive to mutually different spectral regions (the silver halide emulsion will be described later) to correspond to the respective emulsions. Thus, a color image can be easily formed. Examples of color image-forming substances that can be used in the light-sensitive material are described in Japanese Patent Application No. 59-195407.

Dyes and pigments that are themselves colored substances are commercially available, as well as various documents (eg, "Handbook of Dyes" edited by the Society of Synthetic Organic Chemistry, published in 1970, "Handbook of Latest Pigments" edited by the Japan Pigment Technology Association, Known ones described in 1975 can be used. These dyes or pigments are used after being dissolved or dispersed.

On the other hand, examples of the substance that develops color by some energy such as heating, pressurization, and light irradiation are thermochromic compounds,
Known are piezochromic compounds, photochromic compounds, and leuco bodies such as triarylmethane dyes, quinone dyes, indigoid dyes, and azine dyes. All of them develop color by heating, pressurizing, light irradiation or air oxidation.

Examples of the substance that develops a color upon contact with another component include various systems that develop a color by an acid-base reaction, an oxidation-reduction reaction, a coupling reaction, a chelate formation reaction, etc. between two or more components. For example, pressure-sensitive copying paper (pages 29 to 58) and azography (87 to 87) described in "Introduction to Special Paper Chemistry" by Hiroyuki Moriga (published in 1975).
95), thermosensitive coloring due to chemical changes (118-120)
Page) and other well-known color development systems, or a seminar by Kinki Chemical Industry Association "Latest dye chemistry-Attractive utilization as a functional dye and new development-" Proceedings 26-32, (19
The coloring system described in June 19, 80) can be used. Specifically, a color-developing system composed of a colorant having a partial structure such as lactone, lactam, and spiropyran used for pressure-sensitive paper and an acidic substance (developing agent) such as acid clay or phenol; an aromatic diazonium salt or Diazotate, diazosulfonates and naphthols,
Systems utilizing azo coupling reactions of anilines and active methylenes; reactions of hexamethylenetetramine with ferric ions and gallic acid, reactions of phenolphthalein-complexones with alkaline earth metal ions, etc. Chelate forming reaction; a redox reaction such as a reaction between ferric stearate and pyrogallol or a reaction between silver behenate and 4-methoxy-1-naphthol can be used.

Other optional components that can be contained in the photosensitive layer of the photosensitive material using the photosensitive microcapsules of the present invention,
As described above, sensitizing dyes, organic silver salts, various image forming accelerators, thermal polymerization inhibitors, thermal polymerization initiators, development terminators, fluorescent whitening agents, antifading agents, halation or anti-irradiation dyes, Matting agent, anti-smadge agent, plasticizer,
Water release agent, binder, etc.

Examples of sensitizing dyes that can be used in the photosensitive microcapsules and photosensitive materials of the present invention are described in Japanese Patent Application No. 60-139746, and examples of organic silver salts are Japanese Patent Application No. 60-141799. Each is described in the specification. Further, a light-sensitive material using a base or a base precursor is described in Japanese Patent Application No. 60-227528, and a light-sensitive material using a thermal polymerization initiator is described in Japanese Patent Application No. 60-223347. There is. Further, regarding the light-sensitive material using the antifoggant, the applicant of the application of December 26, 1985, (1), (2), (3) and (5) "Light-sensitive material and image forming method" The description of the photosensitive material using a polyethylene derivative as a heat solvent is described in the specification of "Photosensitive Material and Image Forming Method" filed on December 26, 1985 by the present applicant (4). Examples of other components and their use modes are also described in the specification of the application relating to the above-described series of photosensitive materials, and Research Disclosure Vol. 170, June 1978, No. 170.
No. 29 (pages 9 to 15).

The sensitizing dye that can be used in the photosensitive microcapsules and the light-sensitive material of the present invention is not particularly limited, and a silver halide sensitizing dye known in the photographic art can be used. The sensitizing dyes include methine dyes, cyanine dyes, merocyanine dyes, complex cyanine dyes, holopolar cyanine dyes, hemicyanine dyes, styryl dyes and hemioxonol dyes. These sensitizing dyes may be used alone or in combination. In particular, for the purpose of supersensitization, it is common to use a combination of sensitizing dyes. Further, together with the sensitizing dye, a dye which does not have a spectral sensitizing effect itself, or a substance which does not substantially absorb visible light but exhibits supersensitization may be used together. The addition amount of the sensitizing dye is generally about 10 ^{-8 to} 10 ^-2 mol per mol of silver halide.

In the light-sensitive material using the light-sensitive microcapsules of the present invention, the addition of the organic silver salt is particularly effective when heat development processing is planned as a method of using the light-sensitive material. That is, when heated to a temperature of 80 ° C. or higher, the organic silver salt is considered to participate in the redox reaction using the latent image of silver halide as a catalyst. In this case, it is preferable that the silver halide and the organic silver salt are in contact with or in close proximity to each other. Examples of the organic compound that constitutes the organic silver salt include an aliphatic or aromatic carboxylic acid, a thiocarbonyl group-containing compound having a mercapto group or α-hydrogen, and an imino group-containing compound. Of these, benzotriazole is particularly preferable. The above organic silver salt is generally used in an amount of 0.01 to 10 mol, preferably 0.01 to 1 mol, per mol of silver halide. The same effect can be obtained by adding an organic compound (for example, benzotriazole) constituting the organic silver salt to the photosensitive layer instead of the organic silver salt.

Various image forming accelerators can be used in the photosensitive material using the photosensitive microcapsules of the present invention. As the image formation accelerator, promotion of redox reaction between a silver halide (and / or organic silver salt) and a redox agent,
It has a function of promoting the movement of the image-forming substance from the light-sensitive material to the image-receiving material or the image-receiving layer (which will be described later). The image formation accelerator is classified into a base or a base precursor, an oil, a surfactant, an anti-caprying agent, a thermal solvent, etc., from the viewpoint of physicochemical function. However, these substance groups generally have a composite function, and usually have some of the above-mentioned accelerating effects together. Therefore, the above classification is convenient, and in fact, one compound often has a plurality of functions.

Examples of bases, base precursors, oils, surfactants, antifoggants, and hot solvents are shown below.

Examples of preferable bases include alkali metal or alkaline earth metal hydroxides, secondary or tertiary phosphates, borates, carbonates, quinolinates, metaborates as inorganic bases; ammonium hydroxide. Compounds; quaternary alkylammonium hydroxides; hydroxides of other metals, etc., and organic bases include aliphatic amines (trialkylamines, hydroxylamines, aliphatic polyamines), aromatics Amines (N-alkyl-substituted aromatic amines, N-hydroxylalkyl-substituted aromatic amines and bis [p- (dialkylamino) phenyl] methanes), heterocyclic amines, amidines, cyclic amidines, guanidines , Cyclic guanidines are preferable, and those having a pKa of 7 or more are particularly preferable.

Examples of the base precursor include salts of organic acids and bases that are decarboxylated by heating, compounds that release amines by reactions such as intramolecular nucleophilic substitution reaction, Rossen rearrangement, Beckmann rearrangement, etc. Compounds that release and generate a base by electrolysis are preferably used. Specific examples of the base precursor include guanidine trichloroacetic acid, piperidine trichloroacetic acid, morpholine trichloroacetic acid, p-toluidine trichloroacetic acid, 2-picoline trichloroacetic acid, phenylsulfonylacetic acid guanidine, 4-chlorophenylsulfonylacetic acid guanidine, and 4-methyl-. Examples thereof include guanidine sulfonylphenylsulfonylacetate and guanidine 4-acetylaminomethylpropiolate.

In the photosensitive material using the photosensitive microcapsules of the present invention,
The base or base precursor can be used in a wide range of amounts. The base or base precursor is suitably used in an amount of 50% by weight or less in terms of weight of the coating film of the photosensitive layer, more preferably 0.01% by weight to 40% by weight. In the present invention, the base and / or the base precursor may be used alone or as a mixture of two or more kinds.

As the oil, a high boiling point organic solvent used as a solvent for emulsifying and dispersing a hydrophobic compound can be used.

Examples of the surfactant include pyridinium salts, ammonium salts, phosphonium salts described in JP-A-59-74547 and polyalkylene oxides described in JP-A-59-57231.

Examples of the antifoggant include compounds having a 5- or 6-membered nitrogen-containing heterocyclic structure (including compounds having a cyclic amide structure), thiourea derivatives, thioether compounds, thiol derivatives, etc., which are known in the conventional photographic art. Can be mentioned.

As the hot solvent, a compound which can be a solvent for the reducing agent, a compound which is a substance having a high dielectric constant and is known to accelerate the physical development of the silver salt, and the like are useful. As a useful thermal solvent,
Polyethylene glycols described in U.S. Pat. No. 3,347,675, derivatives of polyethylene oxide such as oleic acid ester, beeswax, monostearin and -SO.
High dielectric constant compounds having _2- and / or -CO- groups, polar substances described in U.S. Pat. No. 3,667,959, 1,10-decane described in Research Disclosure, December 1976, pages 26-28. Diol, methyl anisate, biphenyl suberate and the like are preferably used.

The thermal polymerization initiator that can be used for the photosensitive microcapsules and the photosensitive material of the present invention is a compound that generally undergoes thermal decomposition under heating to generate a polymerization initiation species (particularly a radical), and is usually used as an initiator for radical polymerization. It is what has been. Regarding the thermal polymerization initiator, "Addition Polymerization / Ring-Opening Polymerization" 1983, edited by Editorial Committee of Polymer Experiments, Polymer Society of Japan, 1983.
, Kyoritsu Shuppan), pp. 6-18. Specific examples of the thermal polymerization initiator include azobisisobutyronitrile, 1,1′-azobis (1-cyclohexanecarbonitrile), dimethyl-2,2′-azobisisobutyrate, 2,2-azobis ( 2-Methylbutyronitrile), azo compounds such as azobisdimethylvaleronitrile, organic peroxides such as benzoyl peroxide, di-t-peroxide, dicumyl peroxide, t-butylhydroperoxide, cumene hydroperoxide, etc. Thing, p
-Inorganic peroxides such as sodium toluenesulfinate, hydrogen peroxide, potassium persulfate, ammonium persulfate and the like can be mentioned. By using the above thermal polymerization initiator and adjusting the amount of the reducing agent, etc., the polymerizability of either the portion where the latent image of silver halide is formed or the portion where the latent image is not formed is polymerized. The compound can also be polymerized. The amount of the thermal polymerization initiator used is preferably 0.1 to 120% by weight, more preferably 1 to 10% by weight, based on the polymerizable compound. In the system using the above thermal polymerization initiator, 1
It is particularly preferred to use a -phenyl-3-pyrazolidone derivative.

The development terminator that can be used in the photosensitive microcapsules and the light-sensitive material of the present invention is a compound that, after proper development, rapidly neutralizes or reacts with a base to lower the concentration of the base in the film and stop development. It is a compound that interacts with silver and silver salts to suppress development. Specific examples thereof include an acid precursor that releases an acid when heated, an electrophilic compound that causes a substitution reaction with a coexisting base when heated, a nitrogen-containing heterocyclic compound, and a mercapto compound. Examples of the acid precursor include oxime esters described in Japanese Patent Application Nos. 58-216928 and 59-48305, compounds releasing an acid by the Rossen rearrangement described in Japanese Patent Application No. 59-85834, and the like. Examples of electrophilic compounds that undergo a substitution reaction with a base upon heating include compounds described in Japanese Patent Application No. 59-85836.

The binder that can be used in the light-sensitive material and the image-receiving material described later can be contained in the light-sensitive layer or the image-receiving layer (described later) alone or in combination. It is preferable to mainly use a hydrophilic binder. As the hydrophilic binder, a transparent or translucent hydrophilic binder is typical, and examples thereof include gelatin, gelatin derivatives,
It includes proteins such as cellulose derivatives, natural substances such as polysaccharides such as starch and gum arabic, and synthetic polymer substances such as water-soluble polyvinyl compounds such as polyvinyl alcohol, polyvinylpyrrolidone, and acrylamide polymers. Other synthetic polymeric materials include dispersed vinyl compounds in the form of latices, which increase the dimensional stability of photographic materials in particular.

Examples of layers that can be optionally provided in the photosensitive material using the photosensitive microcapsules of the present invention include an image receiving layer, a heating element layer, a protective layer, an antistatic layer, an anti-curl layer, a peeling layer, and a matting agent layer. be able to.

The photosensitive material can form an image on the image receiving material by transferring an unpolymerized polymerizable compound to the image receiving material as described later. Further, in an embodiment in which the photosensitive layer contains a color image-forming substance, the color image-forming substance can be similarly transferred to the image receiving material to form an image. The image receiving material comprises an image receiving layer having a function of fixing a color image forming substance released from the light sensitive material, and a support. Instead of using the image-receiving material, the image-receiving layer can be coated on a support common to the photosensitive layer as an optional layer of the photosensitive material of the present invention as described above.

The image-receiving layer can be configured in various forms using various compounds according to the color-forming system of the color image-forming substance described above. For example, when a color-developing system comprising a color-developing agent and a color-developing agent is used, the image-receiving layer may contain the color-developing agent. Further, the image receiving layer may be composed of at least one layer containing a mordant. The mordant can be selected from compounds known in the photographic art and the like in consideration of conditions such as the type of color image forming substance and used. If necessary, a plurality of mordants having different mordant strengths may be used to form the image receiving element with two or more image receiving layers. When the image receiving layer is located on the surface of the light-sensitive material or the image receiving material, it is preferable to further provide a protective layer.

An example of an image receiving material that can be used together with a light-sensitive material and an image-receiving layer that can be provided in the light-sensitive material are described in Japanese Patent Application No. 60-212284, and a light-sensitive material using a heating element layer is described in Japanese Patent Application No. 60-124. -135568, respectively. In addition, examples of other auxiliary layers and usage modes thereof are also described in the specification of the above-mentioned series of photosensitive materials.

The method of using the photosensitive material using the photosensitive microcapsules of the present invention will be described below.

The light-sensitive material may be imagewise exposed at the same time or after imagewise exposure.
It is used after being polymerized.

Although various exposing means can be used as the exposing method, a latent image of silver halide is generally obtained by imagewise exposure of radiation including visible light. The type of light source and the amount of exposure are
Sensitive wavelength of silver halide (when dye sensitization is performed,
It can be selected according to the sensitized wavelength) and the sensitivity. The original image may be a monochrome image or a color image.

The photosensitive material using the photosensitive microcapsules of the present invention,
By carrying out a development treatment using a liquid described in JP-B-45-111149, etc., the polymerizable compound in the portion where the latent image exists can be polymerized. In addition, as described above, Japanese Patent Application No. 59-19 which performs a polymerization treatment by heating.
Since the method described in 1353 is a dry process,
It has the advantages that it is easy to operate and can be processed in a short time. Therefore, the latter is particularly preferable as the method of using the light-sensitive material.

As the heating method, various conventionally known methods can be used. In addition, the above-mentioned Japanese Patent Application No. 60-13556.
Like the light-sensitive material described in No. 8, the light-sensitive material may be provided with a heating element layer and used as a heating means. The heating temperature is generally 80 ° C to 200 ° C, preferably 100 ° C to 160 ° C. The heating time is generally 1 second to 5 seconds.
Minutes, preferably 5 seconds to 1 minute.

The light-sensitive material subjected to the polymerization treatment as described above bursts the microcapsules containing the unpolymerized polymerizable compound,
The unpolymerized polymerizable compound can be transferred to the image receiving material to form a polymer image on the image receiving material. Further, a dye or a pigment may be fixed to the polymer image to obtain a dye / pigment.

The photosensitive material using the photosensitive microcapsules of the present invention,
In an embodiment in which the photosensitive layer contains a color image-forming substance, the polymerizable compound is subjected to the polymerization and curing treatment as described above to thereby remove the color image-forming substance in the portion where the latent image is formed (or in the portion where the latent image is not formed). By immobilizing the image receiving material on the light-sensitive material on which the color image forming substance in the cured portion is immobilized and then immobilized, the microcapsules in the uncured portion are ruptured and the color image forming substance is received in the image receiving material. Can be transferred to. Various conventionally known methods can be used for the pressing means. An image forming method using an image receiving element such as an image receiving material is described in the above-mentioned Japanese Patent Application No. 60-112284.

The photosensitive material using the photosensitive microcapsules of the present invention,
Black-and-white or color photography and printing materials, printing materials, printing plates, X-ray materials, medical materials (for example, ultrasonic diagnostic machine CRT imaging materials), computer graphic hard copy materials, copying machine materials. There are many uses such as wood.

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

Example 1 Preparation of Silver Halide Emulsion 40 g of gelatin and 23.8 g of potassium bromide were dissolved in 3 of water, heated to 50 ° C., and stirred for 3 times of silver nitrate.
What melt | dissolved 4 g in 200 m of water was added in 10 minutes. Then, a solution prepared by dissolving 3.3 g of potassium iodide in 100 m of water was added over 2 minutes. The pH of the silver iodobromide emulsion thus obtained was adjusted, allowed to settle, excess salts were removed, and then the pH was adjusted to 6.0 to obtain a silver iodobromide emulsion with a yield of 400 g.

Preparation of Photosensitive Composition 0.20 g of the following copolymer and 6.00 g of Pergasscript Red I-6-B (manufactured by Ciba-Geigy Co., Ltd.) were dissolved in 100 g of trimethylolpropane triacrylate. To 18.00 g of the above solution, a solution prepared by dissolving 0.61 g of the following hydrazine derivative I (reducing agent) and 1.22 g of the following developing agent (reducing agent) in 1.80 g of methylene chloride was added. Furthermore, 4.06 g of the above silver halide emulsion was added, and the mixture was stirred with a homogenizer at 15,000 rpm for 5 minutes to obtain a photosensitive composition.

(Copolymer) (Hydrazine derivative I) (Developer) Production of dispersion liquid of photosensitive microcapsules 18.6% aqueous solution of Isoban (manufactured by Kuraray Co., Ltd.)
To 51 g, 48.56 g of a 2.89% aqueous solution of pectin was added, and the photosensitive composition was added to a solution adjusted to pH 4.0 with 10% sulfuric acid.
The photosensitive composition was emulsified in an aqueous solvent by stirring at 00 rpm for 2 minutes.

To 72.5 g of this aqueous emulsion, an aqueous solution of 40% urea 8.3
2 g, resorcin 11.3% aqueous solution 2.82 g, formalin 37% aqueous solution 8.56 g, and ammonium sulfate 8.76% aqueous solution 2.74 g were sequentially added, and heating was continued at 60 ° C. for 2 hours while stirring. Thereafter, the pH was adjusted to 7.0 using a 10% aqueous sodium hydroxide solution, and 3.62 g of a 30.9% aqueous sodium hydrogen sulfite solution was added.

A dispersion of photosensitive microcapsules according to the present invention was manufactured as described above.

[Example 2] Preparation of photosensitive material To 10.0 g of the microcapsule dispersion prepared in Example 1, 1.0 g of 10% aqueous solution of Emarex NP-8 (manufactured by Nippon Emulsion Co., Ltd.), guanidine trichloroacetate 3.69 g of a 10% (water / ethanol = 50/50 volume ratio) solution was added, and the solution was coated on 100 μm thick polyethylene terephthalate using a # 40 coating rod and dried at about 40 ° C. to prepare a light-sensitive material. .

Preparation of Image Receiving Material To 125 g of water was added 11 g of 40% sodium hexametaphosphate aqueous solution, 34 g of zinc 3,5-di-α-methylbenzylsalicylate and 82 g of 55% calcium carbonate slurry were mixed, and coarsely dispersed by a mixer. The liquid was dispersed by a Dynamill disperser, and to 200 g of the obtained liquid, 6 g of 50% styrene-butadiene rubber (SBR) latex and 55 g of 8% polyvinyl alcohol were added and mixed uniformly. An image receiving material was prepared by uniformly applying this mixed solution onto art paper having a weight of 43 g / m ² so as to have a wet film thickness of 30 μm, and then drying.

Image formation and evaluation of light-sensitive material The obtained light-sensitive material was 2,000
After imagewise exposure with lux for 1 second, it was heated for 40 seconds on a hot plate heated to 125 ° C. Then, each of the light-sensitive materials was overlaid on the above image-receiving material and passed through a 350 kg / cm ² pressure roller, whereby a clear positive magenta image was obtained on the image-receiving material. When the density of the image was measured using a Macbeth reflection densitometer, the maximum density was 1.40 and the minimum density was 0.05, and it was found that a clear image with a high ratio of the maximum density and the minimum density was obtained. .

The amount of silver halide transferred onto the image receiving material was 1 mg / m ² or less as measured by a fluorescent X-ray method.
Therefore, it was revealed that substantially no silver halide was transferred.

From the above results and the total amount of silver halide used, it is found that 95% or more of the total amount of silver halide contained in the microcapsules is contained in the wall material that constitutes the outer shell of the microcapsules. Recognize.

Example 3 Preparation of benzotriazole silver emulsion 28 g of gelatin and 13.2 g of benzotriazole were added to 3 parts of water.
It was melted in 000m. The solution was stirred while maintaining the temperature at 40 ° C., and a solution prepared by dissolving 17 g of silver nitrate in 100 m of water was added over 2 minutes. Excess salt was precipitated and removed by adjusting the pH of the obtained emulsion. Thereafter, the pH was adjusted to 6.30, and a benzotriazole silver emulsion having a yield of 400 g was obtained.

Preparation of Dispersion of Photosensitive Microcapsules 4.00 g of Crystal Violet Lactone was used instead of 6.00 g of Pergusscript Red used in the preparation of the photosensitive composition of Example 1, and hydrazine derivative I was used instead of Example 1 except that the following hydrazine derivative II was used in the same amount and 3.35 g of the above benzotriazole silver emulsion was added after the addition of the silver halide emulsion in the preparation of the photosensitive composition of Example 1. Similarly, a dispersion of photosensitive microcapsules according to the present invention was produced.

(Hydrazine derivative II) Example 4 A light-sensitive material was prepared in the same manner as in Example 2 except that the microcapsule dispersion liquid produced in Example 3 was used.

When an image was formed on the above light-sensitive material in the same manner as in Example 2, a clear blue positive image was obtained. When the density of the image was measured using a Macbeth reflection densitometer, the maximum density was 1.50 and the minimum density was 0.05, and it was found that a clear image with a high ratio of the maximum density and the minimum density was obtained. .

[Example 5] 4.06 g of the silver halide emulsion used in Example 1
In the same manner as in Example 1 except that 0.6m of a 0.04% methanol solution of the following dye was added and stirred for 5 minutes as a silver halide emulsion, dispersion of the photosensitive microcapsules according to the present invention was performed. A liquid was produced.

(Pigment) Example 6 A light-sensitive material was prepared in the same manner as in Example 2 except that the microcapsule dispersion liquid produced in Example 5 was used.

A green filter (500 to 600) whose density is continuously changed using a tungsten electrode is used as the above-mentioned light-sensitive material.
imagewise exposure at 2000 lux for 1 second and heating on a photoplate heated to 125 ° C. for 40 seconds. Then, the light-sensitive material was superposed with the image-receiving material used in Example 2 and passed through a 350 kg / cm ² pressure roller,
A clear positive magenta image similar to that in Example 2 was obtained on the image receiving material.

Claims (8)

[Claims] 1. A photosensitive microcapsule containing silver halide, wherein at least 70% of the total amount of silver halide contained in the microcapsule is contained in a wall material constituting an outer shell of the microcapsule. And a core material of the microcapsule contains a polymerizable compound. 2. The photosensitive microcapsule according to claim 1, wherein the core substance further contains a reducing agent. 3. The photosensitive microcapsule according to claim 1, wherein the core substance further contains a color image-forming substance. 4. The average particle size of the microcapsules is
The photosensitive microcapsule according to claim 1, which has a thickness of 0.5 to 50 μm. 5. A photosensitive microcapsule containing silver halide, wherein at least 70% of the total amount of silver halide contained in the microcapsule is contained in a wall material constituting an outer shell of the microcapsule. And a photosensitive material comprising a photosensitive microcapsule containing a polymerizable compound as a core substance of the microcapsule, and a photosensitive layer containing a reducing agent on a support. 6. The light-sensitive material according to claim 5, wherein the reducing agent is contained in the core substance of the microcapsules. 7. The photosensitive material according to claim 5, wherein the photosensitive layer contains a color image-forming substance, and the color image-forming substance is contained in the core substance of the microcapsules. 8. The average particle size of the microcapsules is:
The light-sensitive material according to claim 5, which has a thickness of 0.5 to 50 μm.