JPH04175748A - Light image forming material - Google Patents

Abstract

PURPOSE:To reduce the fog before use and improve the stability of an image section without adversely affecting the image concentration and heat fixing property by using a specific triphenylmethane compound alone or together with an oxidation inhibitor. CONSTITUTION:A coating layer containing an oxidation coloring leuco dye, a micro-capsule storing a photo-oxidizer and a reducing agent is formed on a base. A 4-substituted aminophenyl-indole-3-ilaryl methane compound expressed by the formula I is used for the leuco dye, where R1, R2 indicate an alkyl group or an allyl group, R3, R4 indicate hydrogen atom, an alkyl group or an allyl group, X indicates hydrogen atom or halogen atom, and Ar indicates an aromatic ring which may contain hetero atom. A blue light image forming material which has little fog before use and excellent stability of a colored image and can be thermally fixed can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION "Industrial Application Field" The present invention relates to a heat-fixable leuco dye-based photoimaging material that can be used for blueprint paper, printout paper, overlay films, and the like.

More specifically, the present invention relates to a heat-fixable blue photoimage-forming material that exhibits little fog before use and has excellent stability of colored images.

"Prior Art" Conventionally, photoimageable materials that can be used for applications such as blue paper, printout paper, and overlay films are:
Many photographic applications have been made for so-called free radical photography, in which photosensitive areas are visualized by imagewise exposure.

Particularly effective in this regard is a method of radical oxidative color development of various leuco dyes into their corresponding dyes using a photo-oxidizing agent.

However, because they are sensitive to light, even after exposure to dye images, color formation occurs when exposed to normal indoor light, sunlight, or white light; therefore, they are sensitive to such light. Imaging materials are difficult to handle.

- In order to retain the image once formed, it is necessary to avoid developing color in unexposed areas during image exposure. It is known to preserve the original image by applying a reducing agent solution, such as a free radical scavenger, to the imaged material, for example by spraying or impregnating. However, major problems remain in terms of workability and complexity associated with the wet process. Furthermore, for example, Japanese Patent Application Laid-Open No. 47-12879 proposes a method in which image formation is performed using UV light and fixing is performed by activating a photoreducible substance using visible light. However, this process has major problems in that the light is used twice, which monopolizes the equipment for that time, and that it is necessary to replace the spectral filter in order to use the two types of light. On the other hand, Japanese Patent Publication No. 43-29407 proposes a method in which a reducing heat fixing agent is contained in the photosensitive layer or coated on the photosensitive layer to carry out heat fixing after image exposure. However, this method has a major problem in that the photosensitivity component (leuco dye and photooxidizing agent) and fixing agent coexist in close proximity, resulting in a decrease in sensitivity over time. Furthermore, since the above-mentioned photoimage-forming materials are coated onto a support using an organic solvent, explosion-proof measures are required for manufacturing equipment, which is disadvantageous in terms of both safety and cost.

Therefore, in order to solve these problems, we have discovered a photoimage-forming material in which a rhoico dye and a photooxidizing agent are encapsulated together in microcapsules, and a reducing agent is present outside the microcapsules. . (Special application 1986-2
No. 59111).

However, depending on the leuco dye used in C1 in this photoimage forming material, there are problems such as gradual color development and fogging over time before use, and poor stability of the colored image area. It turned out that.

"Problems to be Solved by the Invention" An object of the present invention is to provide a heat-fixable blue photoimage-forming material that exhibits less fog before use and has excellent stability of colored images.

"Means for Solving the Problem" The object of the present invention is to provide at least (1) microcapsules containing a leuco dye capable of color development by oxidation and a photooxidizing agent;
A photoimage-forming material in which a coating layer containing a reducing agent is formed on a support, characterized in that the leuco dye is a /l-substituted aminophenyl-(indol-3-yl)-arylmethane compound. This was achieved with a photoimageable material that

Among the leuco dyes according to the present invention, 4-substituted aminophenyl-(indol-3-yl)-arylmethane compounds represented by the following general formula CI) are preferred.

General formula [I] A r Jl <In the formula, R1 and R2 may be the same or different and represent an alkyl group or an aryl group, and R3 and R4 may be the same or different and represent a hydrogen atom, an alkyl group or an aryl group. , X represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, or a substituted amino group, and Ar represents an aromatic ring which may contain a hetero atom. ) In the general formula [1], among the groups represented by R1 and R2, an alkyl group having 1 to 1 carbon atoms, and 6 carbon atoms
-12 aryl groups are preferred. The groups represented by R1 and R2 may further have a substituent, and examples of the substituent include an alkyl group, an aryl group, a halogen atom, an alkoxy group,
Preferred are a cyano group, a substituted amine group, a substituted carbonyl group, and the like. Specifically, R1 and R2 are preferably methyl group, ethyl group, butyl group, phenyl group, or tolyl group.

R1 and R2 may be bonded to each other to form a cyclic structure containing a petro atom or an unsaturated bond. For example, 1IR
2) N- and Ly may have a structure such as a pyrrolidinyl group, piperidino group, or morpholino group.

In the general formula [I], among the groups represented by R3, hydrogen atoms, alkyl groups having 1 to 4 carbon atoms, and 6 to 1 carbon atoms
An aryl group with 0 is preferred, and a hydrogen atom, a methyl group, and a phenyl group are particularly preferred.

In the general formula (I), among the groups represented by R4, alkyl groups having 1 to 12 carbon atoms and aryl groups having 6 to 15 carbon atoms are preferable, particularly alkyl groups having 1 to 8 carbon atoms, An aryl group having 6 to 10 carbon atoms is preferred.

The group represented by R4 may further have a substituent, and examples of the substituent include an alkyl group, an aryl group, a halogen atom,
Preferred are an alkoxy group, a cyano group, a substituted amino group, a substituted carbonyl group, and the like. Specifically, R4 is preferably a methyl group, an ethyl group, a butyl group, a hexyl group, an octyl group, a phenyl group, a tolyl group, anisyl group, a chlorphenyl group, a butyloxyphenyl group, or the like.

In the general formula (I), among the groups represented by X, a hydrogen atom, a chlorine atom, a fluorine atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, and a substituted amino group are preferable. The substituted amino group in this case represents a group having the same meaning as (RI R2)N- in general formula CI) in addition to the acylamino group. Specifically, preferred examples of X include a hydrogen atom, a methyl group, a methoxy group, an ethoxy group, a butyloxy group, an acetamido group, and a diethylamino group.

In general formula (1), among the groups represented by Ar, phenyl group, pyridyl group, and pyrimidyl group are preferable. The group represented by Ar may further have a substituent, and preferred examples of the substituent include an alkyl group, an aryl group, a halogen atom, an alkoxy group, a cyano group, a substituted amino group, and a substituted carbonyl group.

Among these, substituted carbonyl groups and substituted amino groups are preferred.

In this case, the substituted amino group is (R
I R2) Represents a group having the same meaning as N-. Specific examples of the substituent include an alkoxycarbonyl group having 2 to 12 carbon atoms, an alkylcarbonyl group having 2 to 10 carbon atoms, a substituted carbamoyl group having 2 to 10 carbon atoms, and a substituted carbamoyl group having 2 to 10 carbon atoms.
~16 dialkylamino groups, 7 to 25 carbon atoms ON
-alkyl-N-arylamino group, number of carbon atoms 6-2
0 diarylamino groups are preferred. Specifically, Ar includes a 2-substituted carbonyl phenyl group, a 4-substituted amino-2-substituted carbonyl phenyl group, a 2-substituted carbonyl-3-pyridyl group, a 3-substituted carbonyl-2-pyridyl group, A 3-substituted carbonyl-2-pyrimidyl group is preferred.

Specific examples of the compound of general formula (I) according to the present invention are listed below, but the present invention is not limited thereto.

1) (4-dimethylaminophenyl)-(1-methyl-
2-Methylindol-3-yl)-phenylmethane 2)(4-dimethylaminophenyl)-(1-methyl-
2-Methylindol-3-yl)-(2-methoxycarbonylphenyl)methane 3)(4-diethylaminophenyl)-(1-methyl-2-ethylindole-3-
yl)-(2-methoxycarbonylphenyl)methane 4
)(4-diethylaminophenyl)-(1-methyl-2
-ethylindol-3-yl)-(4-diethylamino-2-methoxycarbonylphenyl)methane5)(4-diethylamino-2-ethoxyphenyl)-
(1-methyl-2-ethylindol-3-yl)-(
2-methoxycarbonylphenyl)methane 6) (4-diethylamino-2-ethoxyphenyl)-
(1-methyl-2-ethylindol-3-yl)-(
4-diethylamino-2-methoxycarbonylphenyl)methane7)(4-diethylamino-2-methylphenyl)-(
1-methyl-2-ethylindol-3-yl)-(4
-diethylamino-2-methoxycarbonylphenyl)
Methane 8) (4-diethylaminophenyl)-(1-phenyl-2-ethylindol-3-yl)-(2-methoxycarbonylphenyl)methane 9) (4-diethylaminophenyl)-(1-phenyl-2-ethyl indole
3-yl)-(4-diethylamino-2-methoxycarbonylphenyl)methane 10) (4-diethylamino-2-ethoxyphenyl)-(1-phenyl-2-ethylindol-3-yl)-(4-diethylamino -2-methoxycutbonylphenyl)methane+1) (4-N-ethyl-N-p-tolylaminophenyl)-1-methyl-2-ethylindole-3-
yl)-(2-butoxycarbonylphenyl)methane+2) (4-N-ethyl-N-p-)lylamino-2-ethoxyphenyl)-1-methyl-2-ethylindol-3-yl)-(2- ethoxycarbonylphenyl)methane13) (4-diphenylaminophenyl)-(1-
Methyl-2-ethylindol-3-yl)-(2-hexyloxycarbonylphenyl)methane 14) (
4-diethylamino-2-ethoxyphenyl)-(1-
Methyl-2-octylindol-3-yl)-(4-
diethylamino-2-methoxycarbonylphenyl)methane+5) (4-diethylaminophenyl)-(l-methyl-2-phenylindol-3-yl)-(・↓-
diethylamin-2-butoxycarbonylphenyl)methane+6) (4-diethylaminophenyl)-[1-methyl-2-(4-butoxyphenyl)indole-3-
yl]-(4-diethylamino-2-methoxycarbonylphenyl)methane 17) (4-diethylamino-2-ethoxyphenyl)-(2-ethylindol-3-yl)-(2-
methoxycarbonylphenyl)methane1.8) (4
-diethylaminophenyl)-(1-methyl-2-ethylindol-3-yl)-(2-methoxycarbonyl-3-pyridyl)methane 19) (4-diethylaminophenyl)-(1-methyl-2-ethylindole-
3-yl)-(3-methoxycarbonyl-2-pyridyl)methane20) (4-diethylaminophenyl)-
(neemethyl-2-ethylindol-3-yl)-(
Examples include 3-methoxycarbonyl-2-pyrimidyl)methane.

For hue adjustment in the optical image recording material of the present invention, other than the above-mentioned leuco dyes may be used in combination.

For example, those described in US Pat. No. 34,5234 are preferred and are incorporated herein by reference.

1) aminotriarylmethane, 2) aminoxanthine, 3) aminothioxanthine, 4) amino-9,10-dihydroacridine, 5) aminophenoxazine, 6) aminophenothiazine, 7) aminodihydrophenazine, 8) aminodiphenylmethane , 9) Leucomendamine, 1.0> Aminohydrocinnamic acid (cyanoethane, leucomethine), 11) Hydrazine, 12) Leucoidigoid dye, 13) Amino-2,3-dihydroanthraquinone, 14
) tetrahalo p, p, -biphenol, 15) 2-(
p-hydroxyphenyl)-4,5-diphenylimidazole, 16) Phenethylaniline.

Among these leuco forms, 1) to 9) form a parent dye by losing one hydrogen atom, and 10) to 16) form a parent dye by losing two hydrogen atoms.

Specifically, 2-(2-chlorophenyl)amino-6-
N,N-dibutylamino-9-(2-methoxycaryl)-phenylxanthine, 2-N,N-dibenzylamino-6-N,,N-diethylamino-9-(2
-methoxycarbonyl)-phenylxanthine, benzo(a) -6-N, N-diethylamino-9-(
2-methoxycarbonyl)-phenylxanthine, 2-
(2-chlorophenyl)-amino-6-N,N-dibutylamino-9-(2-methylphenylcarboxamide)
-Phenylxanthine, 3,6-simethoxy9-(2
-methoxycarbonyl)-phenylxanthine, 3.6
-dinitoxyethyl-9-(2-methoxycarbonyl)
- phenylxanthine, benbuyl leucomethylene blue, 3,7-bis-diethylaminophenoxazine,
Tris(4-dimethylaminophenyl)methane, bis(
4-dimethylaminophenyl)-(4-dimethylamino-2-methoxycarbonylphenyl)methane, bis(4
-diethylaminophenyl)-(4-diethylamino-
Examples include 2-methylphenyl)methane, bis(4-diethylamino-2-methylphenyl)-(4-diethylaminophenyl)methane, and tris(4-diethylamino-2-methylphenyl)methane.

Preferred photooxidants that can be used in the photoimaging materials of this invention are generally inert, but include visible, ultraviolet, infrared,
! When exposed to actinic radiation such as leuco dyes, a chemical species is generated that oxidizes the leuco dye to its colored form.

Typical photo-oxidizing agents include lophine dimer compounds such as the 2,4°5-triarylimidazole dimer described in Japanese Patent Publication No. 62-39728 and Japanese Patent Publication No. 63-2099. Azide compounds such as 2-azidobenzoxazole, benzoyl azide, and 2-azidobenzimidazole described in U.S. Pat. No. 3,282,693; U.S. Pat. No. 3,61556;
3'-ethyl-1-methoxy-2-pyridothiacyanine verchlorate described in No. 8, pyridinium compounds such as 1-methoxy-2-methylpyridinium-p-toluenesulfonate, N-promosuccinimide, tribromomethylphenyl Sulfone, 2-trichloromethyl-5-(
Organic halogen compounds such as p-butoxystyryl)-1゜3.4-oxadiazole and 2,6-dydrichloromethyl-4-(p-methoxyphenyl)-triazine, Lecture at the 1968 Spring Research Conference of the Photographic Society of Japan Examples include the azide polymer described on page 55 of the abstract. Among these, lophine dimer compounds and organic halogen compounds are preferred, and the combination of both is optimal because high sensitivity can be achieved.

In producing the photoimage forming material of the present invention, the leuco dye and the photooxidizing agent are preferably mixed at a molar ratio of 10:1 to 1:10, and a more preferable mixing ratio is 22:1 to 1:1.
It is 2.

Preferred capsules in the present invention are those that prevent contact between substances inside and outside the capsule at room temperature due to the substance isolation effect of the microcapsule walls, and that permeability of substances increases only when heated above a certain temperature.

The permeation start temperature of this phenomenon can be freely controlled by appropriately selecting the capsule wall material, capsule core material, and additives. In this case, the permeation start temperature is
This corresponds to the glass transition temperature of the capsule wall.

In order to control the glass transition temperature specific to the capsule wall, it is necessary to change the type of capsule wall forming agent. Wall materials that can be used in the present invention include polyurethane, polyurea, polyamide, polyester, polycarbonate, etc., among which polyurethane and polyurea are particularly preferred.

The microcapsules used in the present invention are made by emulsifying a core material containing a photoimage-forming substance such as a leuco dye and a photooxidizing agent, and then forming a wall of a polymeric material around the emulsified oil droplets. In this case, the wall-forming actant is added to the interior of the oil droplet and/or to the exterior of the oil droplet.

High boiling point oils are used as organic solvents to dissolve the photoimage-forming substances mentioned above, specifically phosphoric acid esters, phthalic acid esters, acrylic acid esters, methacrylic acid esters, other carboxylic acid esters, fatty acid amides, alkyl esters, etc. Examples include biphenyls, alkylated terphenyls, alkylated phthalenes, diarylethanes, and chlorinated paraffins.

In the present invention, a low boiling point auxiliary solvent can also be added to the above organic solvent. Specific examples of the auxiliary solvent include ethyl acetate, isopropyl acetate, butyl acetate, methylene chloride, cyclohexanone, and the like.

In order to stably form emulsified oil droplets, protective colloids and surfactants can be added to the aqueous phase. Water-soluble polymers can generally be used as protective colloids.

In the present invention, the size of the microcapsules is set at a volume average of 2
It is preferably 0 μm or less, more preferably 1 μm or less.

In the photoimageable materials of the present invention, antioxidants can be included in the microcapsules to further provide stability before use. Preferred antioxidants include phenolic compounds, hydroquinone compounds, and catechol compounds.

Specifically, 2.6-di-t-butyl-4-methylphenol, 2.4.6-tri-t-butylphenol,
2.5-di-t-butylhydroquinone, 2.3-di-t-butylhydroquinone, 2.5-di-t-octylhydroquinone, 2.5-di-t-amylhydroquinone, 3.6-di-1 -butylcatechol and the like.

In producing the photoimage-forming material of the present invention, a photooxidizing agent and an antioxidant are preferably mixed in a molar ratio of 10:0.001 to 10:2, and a more preferable mixing ratio is 10:0.001 to 10:2.
01-10:1.

The photoimage-forming material of the present invention can reliably obtain a stable image by performing a heat treatment after image formation by exposure. That is, the fixing mechanism of the photoimage-forming material of the present invention is such that the photooxidizing agent and the reducing agent come into contact with each other through the capsule wall by heating, so that even if the photooxidizing agent is subsequently activated, the reducing agent no longer acts. This is done by deactivating the oxidizing agent.

Such a reducing agent acts as a so-called free radical scavenger that traps the free radicals of the activated photooxidant.

For example, hydroquinone compounds and aminophenol compounds having a hydroxyl group on a benzene ring and at least another hydroxyl group or amino group at another position on the benzene ring described in U.S. Pat. Hydrazide compounds, compounds selected from guanidine derivatives, alkylene diamine derivatives, and hydroxyamine derivatives, phenylhydrazine compounds, and the like can be used.

In the photoimage-forming material of the present invention, the reducing agent is solid-dispersed using a sand mill or the like, or dissolved in oil.
It is best to use it by emulsifying and dispersing it. It is preferable to use a protective colloid during solid dispersion or emulsion dispersion.

The preferred amount of reducing agent is from 1 to 1 on a mole basis of the photooxidant component.
．． 00 times the molar amount, more preferably 5 to 20 times the molar amount.

Image fixation in the present invention can be effectively achieved by bringing the photooxidizing agent and reducing agent into contact with each other through the capsule wall by heating as described above, but a synergistic effect is expected by performing heating and pressurization at the same time. I can do both. It is preferable to use a melting point depressant such as p-benzyloxyphenol or p-4 luenesulfonamide in combination with this reducing agent because low-temperature fixing becomes possible.

In the present invention, there is no problem in adding a known sensitizer into the capsule.

The photoimage-forming material of the present invention can be prepared by coating on a support a dispersion of microcapsules containing such a leuco dye and a photooxidizing agent and a reducing agent.

A binder, a pigment, a wax, a metal soap, or a surfactant may be added to the above-mentioned microcapsules containing a leuco dye and a photooxidizing agent and a dispersion of a reducing agent, and the coating amount of the photoimage forming layer in the present invention may be is 3~ in terms of solid content
30 g/m2, especially 5 to 20 g/m2 is preferred.

Suitable materials for the support include papers ranging from tissue vapor to heavy cardboard, regenerated cellulose, cellulose acetate, cellulose nitrate, polyethylene terephthalate, polyethylene, polyvinyl acetate, polymethyl methacrylate, polyvinyl chloride, and the like.

Methods for coating the support include air knife coating, curtain coating, slide coating, roller coating, dip coating, wire barcoding, blade coating, gravure coating, spin coating, or extrusion coating. etc., but are not limited to these.

Further, if necessary, an undercoat layer may be provided on the support, or a coating layer may be provided on the photoimage forming layer. The undercoat layer and the coating layer contain a binder and/or a pigment as a main component.

Any convenient light source can be used in the present invention for activating the photooxidant and forming the image of the leuco dye. Conventional light sources include fluorescent lamps, mercury lamps, metal halide lamps, xenon lamps, tungsten lamps, and the like.

The photoimage-forming material of the present invention is used as a photoimage-forming composition with improved background photoyellowing and dusting.

Examples are shown below, but the present invention is not limited thereto. Note that "parts" indicating the amount added indicate "parts by weight."

"Example" Example 1 Specific compound example of the present invention (4) 1 part, 2,2'-bis-
(0-chlorophenyl)-4,4', 2 parts of 5°5'-tetraphenylbiimidazole, 0.0 parts of tribromomethylphenylsulfone. 4 parts and 10 parts of a 75% by weight ethyl acetate solution of the xylylene diisocyanate/trimethylolpropane adduct were added to and dissolved in a mixed solvent of 16 parts of ethyl acetate and 14 parts of dicyclohexyl phthalate. This solution was added to 64 parts of a 5% by weight aqueous solution of carboxy-modified polyvinyl alcohol and emulsified and dispersed at 20°C to obtain an emulsion with an average particle size of 1 μm. Add 58% water to the resulting emulsion
of the mixture was added and stirring was continued for 3 hours at 40°C. Thereafter, the mixture was returned to room temperature and filtered to obtain a capsule dispersion.

Next, 9.4 parts of 1-phenylpyrazolidin-3-one (phenidone A) and 0.9 parts of p-)luenesulfonamide
1 part was added to 23 parts of a 6% by weight aqueous solution of carboxy-modified polyvinyl alcohol and dispersed in a horizontal sand mill to obtain a reducing agent-containing dispersion having an average particle size of 1 μm.

Next, a coating liquid having the following composition was prepared.

The above capsule dispersion 165.4 parts The above phenidone A dispersion 33.3 parts 20% silica (Thyroid 404, manufactured by Fuji Davison Chemical Co., Ltd.) dispersion
7 parts 30% epoxidized polyamide resin (FL-71, manufactured by Toho Chemical Co., Ltd.)
3 parts 10% sulfosuccinic acid 4-methylpentyl ester aqueous solution 3
This coating solution was applied to a high-quality paper (basis weight 76 g/m, 2 ) using a coating rod to a solid coating amount of 10 g/m 2 and dried at 50° C. to obtain a photoimage-forming material.

Example 2 Compound (6) was substituted for compound (4) in Example 1.
) was carried out in exactly the same manner as in Example 1, except that a photoimage-forming material was obtained.

Example 3 [Effect of antioxidant] Specific compound example of the present invention (4) 1 part, 2,2'-bis-
(0-chlorophenyl) -4,4', 5゜5'-
2 parts of tetraphenylbiimidazole, 0.4 part of tribromomethylphenylsulfone, 2,5-di-tertiary
0.1 part of octylhydroquinone and 10 parts of a 75% by weight ethyl acetate solution of the xylylene diisocyanate/trimethylolpropane adduct were added to and dissolved in a mixed solvent of 16 parts of ethyl acetate and 14 parts of dicyclohexyl phthalate.

This solution was added to 64 parts of a 5% by weight aqueous solution of carboxy-modified polyvinyl alcohol, and emulsified and dispersed at 20°C.
An emulsion with an average particle size of 1 μm was obtained. Add 5 liters of water to the resulting emulsion
8 parts were added and stirring continued at 40°C for 3 hours. Thereafter, the mixture was returned to room temperature and filtered to obtain a capsule dispersion. The rest was carried out in the same manner as in Example 1 to obtain a photoimage forming material.

Example 4 Compound (12) was substituted for compound (4) in Example 3.
) was carried out in exactly the same manner as in Example 3, except that a photoimage-forming material was obtained.

Comparative Example 1 The same procedure as in Example 1 was carried out except that leucocryphal violet [tris-p-dimethylaminophenylmethane] was used instead of compound (4) in Example 1.
A photoimageable material was obtained.

Comparative Example 2 Example 1 was carried out in exactly the same manner except that leucocryphal violet (tris-p-dimethylaminophenylmethane) was used instead of compound (4) in Example 3.
A photoimageable material was obtained.

The photoimage forming materials obtained in Examples and Comparative Examples were tested as follows. The results are shown in Table 1.

(1) Image density A fresh sample is irradiated with light using a jet light (ultra-high-pressure mercury lamp, manufactured by Oak Co., Ltd.) through a line drawing original, and then passed through a heated roller at 135°C at a speed of 450 mm/min, unexposed. established the department. Thereafter, the image density of the exposed area was measured using a Macbeth reflection densitometer.

(2> Fog Refreshed sample before use was stored in the dark at 60° C. and 30% for one week, and the fog density was measured using a Macbeth reflection densitometer.

(3) Stability of image area After irradiating the sample with the above heat fixation using a fluorescent lamp at 32,000 lux for 10 hours, the density of the image area was measured using a Macbeth reflection densitometer. compared with.

"Effects of the Invention" By using the specific triphenylmethane compound of the present invention alone or in combination with an antioxidant, it is possible to eliminate fogging and image formation before use without adversely affecting image density or heat fixability. It can be seen that the stability of the part was improved.

Table 1

Claims (2)

[Claims] (1) A photoimage-forming material in which a coating layer containing at least [1] microcapsules containing a leuco dye capable of oxidative color development and a photooxidizing agent, and [2] a reducing agent is formed on a support. A photoimage-forming material characterized in that the dye is a 4-substituted aminophenyl-(indol-3-yl)-arylmethane compound. (2) The photoimage-forming material according to claim (1), wherein an antioxidant is encapsulated in the microcapsules.