JPH05127302A - Image forming material - Google Patents

Abstract

PURPOSE:To obtain an image forming material ensuring high density of a color image, having excellent stability and developing a black hue by using a specified leuco dye. CONSTITUTION:When a coating layer contg. at least a reducing agent and microcapsules housing a leuco dye capable of developing a color by oxidation and a photooxidizing agent is formed on a substrate to obtain an image forming material, a xanthene deriv. represented by the formula is used as the leuco dye. In the formula, R<1> is H, alkyl, alkenyl, alkynyl or aryl, R<2> is alkyl, alkenyl, alkynyl or aryl, R<3> is alkyl, aryl or halogen, R<4> is alkyl or substd. carbonyl, R<5> is methyl or halogen and each of R<6>-R<8> is H, methyl or halogen.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming material containing a heat-fixable leuco dye, which can be used for proof paper, printout paper, overlay film, etc. The present invention relates to an image-forming material which is highly stable and provides a black color image with a colored hue of black.

[0002]

2. Description of the Related Art Conventionally, proof paper, printout paper,
Image-forming materials that can be used in applications such as overlay films have been used in many photographic applications as so-called free radical photography in which a light-sensitive portion is visualized by imagewise exposure.

Several attempts have been made to obtain a black color image in such an image forming material. For example, U.S. Pat. No. 4,078,934 discloses a method of obtaining a black image by mixing two kinds of leuco dyes using a biimidazole compound as a photo-oxidizing agent. Similarly, US Pat. No. 4,379,835 discloses a mixed system of leuco dyes, which uses a nitrate as a photo-oxidizing agent. However, problems such as difficulty in hue adjustment associated with color mixing cannot be avoided.

As a method of using a leuco dye alone, JP-A-61-137876 discloses a system using a xanthene compound having amino groups at the 2- and 6-positions. However, the leuco dyes described in the above publications are 2
A xanthene compound in which a phenyl group having no substituent is bonded to the amino group at the -position, for example, Examples 1 to 5
When the compounds described in 9, 11, etc. are made to develop color by the method described there, (1) the color density is insufficient, and (2) when the amount of light is increased to obtain a sufficient density, the hue becomes red. It was found that there was a problem that the taste changed.

The present inventors have studied various leuco compounds in order to obtain a stable black colored image in the above-mentioned image forming material, and have confirmed that a specific leuco dye produces a good black color. Heading, it came to complete the present invention.

[0006]

SUMMARY OF THE INVENTION It is, therefore, an object of the present invention to provide an image forming material having a high density of a color image and excellent stability and a black color hue.

[0007]

The present invention provides at least the following:
In an image-forming material in which a coating layer containing a reducing agent and a microcapsule containing an oxidatively coloring leuco dye and a photo-oxidizing agent is formed on a support, the leuco dye has the following general formula (1):

[0008]

[Chemical 2]

(In the formula, R ¹ is a hydrogen atom, an alkyl group,
Represents an alkenyl group, an alkynyl group or an aryl group, R
² represents an alkyl group, an alkenyl group, an alkynyl group or an aryl group, R ³ represents an alkyl group, an aryl group or a halogen atom, R ⁴ represents an alkyl group or a substituted carbonyl group, and R ⁵ represents a methyl group. Or a halogen atom, R ⁶ , R ⁷ and R ⁸ each independently represent a hydrogen atom, a methyl group or a halogen atom, and R ¹ and R ² are
They may be bonded to each other to form a ring which may contain an unsaturated atom or a hetero atom, and the xanthene ring or the benzene ring bonded to the 9-position thereof may have one or more other same or different substituents. The image forming material is a xanthene derivative represented by

The preferred embodiments of the present invention will be described below. (1) The image forming material as described above, wherein the microcapsules further contain an antioxidant. (2) The ratio of the leuco dye to the photo-oxidizing agent is 10: 1.
The image-forming material as described above, wherein the molar ratio is ˜1: 10. (3) The amount of the reducing agent is 1 to 10 of the amount of the photooxidizing agent.
The image-forming material as described above, characterized in that it is 0 mole times.

The leuco dye used in the present invention is
It is an aminoxanthene derivative represented by the general formula (1).

R ¹ , R ² and R ³ in the general formula (1)
Of the groups represented by, the alkyl group has 1 to 10 carbon atoms,
Particularly, those having 1 to 6 carbon atoms are preferable, those having 2 to 10 carbon atoms, particularly those having 2 to 6 carbon atoms are preferable for the alkenyl group, and the alkynyl group has 2 to 1 carbon atoms.
0, especially those having 2 to 6 carbon atoms are preferable, and the aryl group has 6 to 12 carbon atoms, especially 6 to 10 carbon atoms.
Are preferred. In addition, among the groups represented by R ⁴ ,
The alkyl group has 1 to 10 carbon atoms, especially 1 to 10 carbon atoms.
Those of 6 are preferred. Further, among the groups represented by R ⁴ , the substituent of the substituted carbonyl group is an alkyl group,
Alkenyl group, alkynyl group, aryl group, substituted amino group, alkoxy group, aryloxy group, alkylthio group, halogen atom, nitro group, cyano group, substituted carbamoyl group, substituted oxycarbamoyl group, substituted oxysulfonyl group, hetero A ring etc. can be mentioned. These substituents may further have a substituent. R ³ , R ⁵ ,
Of the groups represented by R ⁶ , R ⁷ and R ⁸ , the halogen atom is preferably a chlorine atom or a fluorine atom. R
¹ and R ² are bonded to each other to form a ring containing an unsaturated atom or a hetero atom (for example, a piperidinino group, a 1-pyrrolidinyl group,
1-pyrrolyl group, morpholino group) may be formed.

Examples of the above alkyl group include methyl,
Examples thereof include ethyl, propyl, isopropyl, butyl, isobutyl, isoamyl and hexyl. Examples of the above alkenyl group include 2-propenyl and 2-
Butenyl, 2-methyl-2-propenyl and the like can be mentioned. Examples of the above-mentioned alkynyl group include 2-propynyl, 3-butynyl and the like. Examples of the above aryl group include phenyl, naphthyl, tolyl, 4-methoxyphenyl and the like.

R ¹ , R ² and R ³ in the general formula (1)
The group represented by is further an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a substituted amino group, an alkoxy group,
It may be substituted with an aryloxy group, an alkylthio group, a halogen atom, a nitro group, a cyano group, a substituted carbamoyl group, a substituted oxycarbamoyl group, a substituted oxysulfonyl group, a heterocycle or the like. These substituents may further have a substituent. R ¹ , R substituted with these groups
Preferred examples of the groups represented by ² and R ³ include alkoxyalkyl groups having 2 to 10 carbon atoms (for example, 2-methoxyethyl, 2-ethoxyethyl, 3-methoxypropyl), tetrahydrofurfuryl group and the like. Can be mentioned.

As a preferred example of the substituted carbonyl group represented by R ⁴ substituted with the above groups, an alkoxycarbonyl group having 2 to 15 carbon atoms, particularly 2 to 10 carbon atoms (for example, Methoxycarbonyl, ethoxycarbonyl, isopropyloxycarbonyl), an N-alkylcarbamoyl group having 2 to 12 carbon atoms, particularly 2 to 8 carbon atoms (for example, N-ethylcarbamoyl, N,
Mention may be made of N-diethylcarbamoyl, N-butylcarbamoyl) and N-arylcarbamoyl groups having 6 to 15 carbon atoms, especially 6 to 10 carbon atoms (for example N-phenylcarbamoyl).

From the viewpoint of easy availability of raw materials, R ¹ and R
² is preferably ethyl, butyl, isoamyl or hexyl, and R ³ is preferably methyl, ethyl, chlorine atom or phenyl. Further, R ⁴ is preferably methoxycarbonyl, N-phenylcarbamoyl or N-ethylcarbamoyl.

The group represented by R ⁵ is preferably a methyl group or a chlorine atom in order for the image-forming material of the present invention to exhibit particularly excellent effects. To get the black hue, R
^The groups represented by ⁶ , R ⁷ and R ⁸ are also preferably a methyl group or a chlorine atom.

In the general formula (1), the xanthene ring or the benzene ring bonded to the 9-position thereof may further have the same or different substituents (eg, lower alkyl group such as methyl group and ethyl group, chlorine atom). , And a halogen atom such as a bromine atom).

The leuco dye in the image-forming material of the present invention is a reduced form of a dye having one or two hydrogen atoms, and is colored by removing the hydrogen atom and in some cases adding an additional electron. To form a dye. Since such leuco dyes are substantially colorless or have a light color, they serve as a means for forming a pattern when they are oxidized to develop a color. This oxidation is achieved in the present invention by the presence of a photooxidant. The photo-oxidizing agent is activated by irradiation with light and reacts with the leuco dye to form a colored image only in the light-irradiated portion.

The xanthene derivative represented by the general formula (1) used as a leuco dye in the present invention is
The substituent at the ortho position of the anilino group bonded to the 2-position [R ⁵ of the general formula (1) and R ⁸ other than a hydrogen atom] makes the hydrogen atom of the anilino group difficult to be electronically oxidized. It plays such a role, and side reactions are less likely to occur during color development due to oxidation. Therefore, the desired color image can be obtained without discoloration. Further, the substituents at the meta and para positions of the anilino group of the xanthene derivative [general formula (1)
R ⁶ and R ⁷ ] also have an important influence on the hue at the time of color development of the xanthene derivative. In order to obtain a black hue by using the image forming material of the present invention, the anilino group of the xanthene derivative is 2,4-dimethylanilino group, 2,6
A dimethylanilino group and a 2,4,6-trimethylanilino group are preferred.

Specific examples of the xanthene derivative represented by the general formula (1) (leuco dye used in the present invention) are shown below, but the present invention is not limited thereto. 9- (2-methoxycarbonylphenyl) -2- (2,
4-dimethylphenyl) amino-3-methyl-6-diethylaminoxanthene, 9- (2-ethoxycarbonylphenyl) -2- (2,4-dimethylphenyl) amino-3-methyl-6-diethylaminoxanthene, 9-
(2-isopropoxycarbonylphenyl) -2-
(2,4-Dimethylphenyl) amino-3-methyl-6
-Diethylaminoxanthene, 9- (2-methoxycarbonylphenyl) -2- (2,4-dimethylphenyl)
Amino-3-methyl-6-dibutylaminoxanthene,
9- (2-methoxycarbonylphenyl) -2- (2,
4-dimethylphenyl) amino-3-methyl-6-N-
Ethyl-Np-tolylaminoxanthene, 9- (2-
Diphenylmethyloxycarbonylphenyl) -2-
(2,4-Dimethylphenyl) amino-3-methyl-6
-Diethylaminoxanthene, 9- (2-triphenylmethyloxycarbonylphenyl) -2- (2,4-dimethylphenyl) amino-3-methyl-6-N-ethyl-Np-tolylaminoxanthene, 9- ( 2-methoxycarbonylphenyl) -2- (2,6-dimethylphenyl) amino-3-methyl-6-diethylaminoxanthene, 9- (2-isopropoxycarbonylphenyl)
-2- (2,6-Dimethylphenyl) amino-3-methyl-6-diethylaminoxanthene, 9- (2-methoxycarbonylphenyl) -2- (2,6-dimethylphenyl) amino-3-methyl-6- Dibutylaminoxanthene, 9- (2-diphenylmethyloxycarbonylphenyl) -2- (2,6-dimethylphenyl) amino-
3-methyl-6-diethylaminoxanthene, 9- (2
-Triphenylmethyloxycarbonylphenyl) -2
-(2,6-Dimethylphenyl) amino-3-methyl-
6-diethylaminoxanthene, 9- (2-methoxycarbonylphenyl) -2- (2,4,6-trimethylphenyl) amino-3-methyl-6-diethylaminoxanthene, 9- (2-isopropoxycarbonylphenyl) -2 -(2,4,6-Trimethylphenyl) amino-3-methyl-6-diethylaminoxanthene, 9-
(2-Methoxycarbonylphenyl) -2- (2,4,
6-Trimethylphenyl) amino-3-methyl-6-dibutylaminoxanthene, 9- (2-diphenylmethyloxycarbonylphenyl) -2- (2,4,6-trimethylphenyl) amino-3-methyl-6-diethylamino Xanthene, 9- (2-triphenylmethyloxycarbonylphenyl) -2- (2,4,6-trimethylphenyl) amino-3-methyl-6-N-ethyl-N-
p-tolylaminoxanthene, 9- (2-methoxycarbonylphenyl) -2- (2,4-dimethylphenyl)
Amino-3-chloro-6-diethylaminoxanthene,
9- (2-methoxycarbonylphenyl) -2- (2,
6-Dimethylphenyl) amino-3-chloro-6-diethylaminoxanthene, 9- (2-methoxycarbonylphenyl) -2- (2,4,6-dimethylphenyl) amino-3-chloro-6-diethylaminoxanthene, 9
-(2-Methoxycarbonyl-4-methylphenyl)-
2- (2,4-dimethylphenyl) amino-3-methyl-6-diethylaminoxanthene, 9- (2-methoxycarbonyl-3,4,5,6-tetrachlorophenyl)
-2- (2,6-Dimethylphenyl) amino-3-methyl-6-diethylaminoxanthene.

In the present invention, another leuco dye may be used in combination with the xanthene derivative represented by the general formula (1). Examples of leuco dyes that can be used in combination include US Pat.
445234, JP 61-137876, JP 62-94841, and JP 63-15.
The following compounds described in Japanese Patent No. 787, etc. are preferable. When another leuco dye is used in combination with the xanthene derivative, the molar ratio of xanthene derivative: other leuco dye is preferably 100: 0.1 to 1:10. (A) Aminotriarylmethane, aminoxanthene, aminothioxanthene, amino-9,10-dihydroacridine, aminophenoxazine, aminophenothiazine, aminodihydrophenazine, aminodiphenylmethane, leucoindamine, (B) aminohydrocinnamic acid (cyanoethane) , Leucomethine), hydrazine, leucoin digoid dye, amino-2,3-dihydroanthraquinone, tetrahalo-p, p'-biphenol, 2-
(P-Hydroxyphenyl) -4,5-diphenylimidazole, phenethylaniline. Among these leuco forms, (A) loses one hydrogen atom and (B) loses two hydrogen atoms to form a host dye.

Specifically, tris (4-dimethylaminophenyl) methane, tris (4-diethylaminophenyl) methane, tris (4-diethylamino-2-methylphenyl) methane, bis (4-diethylaminophenyl)- (4-Diethylamino-2-methylphenyl) methane, bis (4-diethylamino-2-methylphenyl)-(4-diethylaminophenyl) methane, bis (1-ethyl-2-methylindol-3-yl) -phenylmethane , 3,6-bis (diethylamino) -9-
Phenylxanthene, 3,6-bis (dimethylamino)
-9- (o-methoxycarbonylphenyl) xanthene, 2- (2-chlorophenyl) amino-6-dibutylamino-9- (2-methoxycarbonylphenyl) xanthene, 2-dibenzylamino-6-diethylamino-
9- (2-methoxycarbonylphenyl) xanthene,
Benzo [a] -6-N, N-diethylamino-9- (2
-Methoxycarbonylphenyl) xanthene, 2- (2
-Chlorophenyl) -amino-6-dibutylamino-9
Examples thereof include-(2-methylphenylcarboxamidophenyl) xanthene, 3,6-dimethoxy-9- (2-methoxycarbonyl) -phenylxanthene, benzoylleucomethylene blue, and 3,7-bis-diethylaminophenoxazine.

The image-forming material of the present invention is the same as the image-forming material described in JP-A-2-44, except that the above xanthene derivative is used as the leuco dye.

Preferred photo-oxidizing agents which can be used in the image-forming material of the present invention are inert until exposed to actinic radiation such as visible light, ultraviolet rays, infrared rays and X-rays. When exposed to light, it produces chemical species that oxidize the leuco dye to its chromogenic form.

As a typical photo-oxidizing agent, Japanese Examined Patent Publication No. 62-
Lophine dimer compounds such as 2,4,5-triarylimidazole dimers described in Japanese Patent Publication No. 39728 and Japanese Patent Publication No. 63-2099, 2-azidobenzoxazole, benzoylazide, and 2-described in U.S. Pat. No. 3,282,693. Azide compounds such as azidobenzimidazole, pyridinium such as 3'-ethyl-1-methoxy-2-pyridothiacyanine perchlorate and 1-methoxy-2-methylpyridinium-p-toluenesulfonate described in U.S. Pat. No. 3,615,568. Compound, N-bromosuccinimide, tribromomethylphenyl sulfone, 2-trichloromethyl-5- (p-butoxystyryl) -1,3,4-oxadiazole, 2,6-ditrichloromethyl-4- (p -Methoxyphenyl) -triazine and other organic halogens Compounds, mention may be made of an azide polymer, and the like of the Society of Photographic Science and Technology of Japan 1968 Spring Research Workshop Abstracts page 55 described. Of these, the lophine dimer compound and the organic halogen compound are preferable, and the combined use of both is most preferable because high sensitivity can be realized.

In the production of the image forming material of the present invention, the leuco dye and the photo-oxidizing agent are used in a molar ratio of 10: 1 to 1: 1.
It is advisable to mix them in a ratio of 10, and a more preferable mixing ratio is a molar ratio of 2: 1 to 1: 2.

The preferred microcapsules for encapsulating the leuco dye and the photo-oxidizing agent in the present invention are heated to a certain temperature or higher at room temperature due to the substance-separating action of the microcapsule wall to prevent contact between substances inside and outside the capsule. Only when the permeability of the substance is increased. With respect to this phenomenon, the permeation initiation temperature can be freely controlled by appropriately selecting the capsule wall material, the capsule core substance, and the additive. The permeation initiation temperature in this case corresponds to the glass transition temperature of the capsule wall.

In order to control the glass transition temperature inherent to the microcapsule wall, it is necessary to change the type of capsule wall forming agent. Examples of the capsule wall material that can be used in the present invention include polyurethane, polyurea, polyamide,
Examples thereof include polyesters, polycarbonates and the like, and blends thereof. Among them, polyurethane and polyurea are particularly preferable.

The microcapsules used in the present invention are obtained by emulsifying a core substance containing an image forming substance such as a leuco dye and a photo-oxidizing agent, and then forming a wall of the wall forming material around the emulsified oil droplets. Made In this case, a reactant for forming a wall is added inside the oil droplet and / or outside the oil droplet.

A high boiling point oil (having a boiling point of 120 ° C. or higher) is used as the organic solvent for dissolving the above-mentioned image forming substance. As the high boiling point oil, phosphoric acid ester, phthalic acid ester, acrylic acid ester, methacrylic acid ester, other carboxylic acid ester, fatty acid amide, alkylated biphenyl, alkylated terphenyl, alkylated naphthalene, diarylethane, chlorinated paraffin Etc. Specific compounds include, for example, JP-A 60-242094 and JP-A 62-62.
Those described in Japanese Patent No. 75409 can be used.

In the present invention, the above high boiling point oil has a low boiling point auxiliary solvent (having a boiling point of less than 120 ° C.).
Can also be added. Specific examples of the auxiliary solvent include ethyl acetate, isopropyl acetate, butyl acetate, methylene chloride and cyclohexanone.

In order to stably produce emulsified oil droplets, a protective colloid or a surfactant can be added to the aqueous phase. As the protective colloid, generally, a water-soluble polymer (eg, polyvinyl alcohol, gelatin, cellulose derivative, etc.) can be used.

In the present invention, the size of the microcapsules is, in particular, from the viewpoint of improving the image resolution and handling.
The volume average particle size according to the measuring method described in JP-A-60-214990 is preferably 20 μm or less, and particularly preferably 4 μm or less. The lower limit of the capsule size depends on the nature of the substrate or support, but is generally preferably 0.1 μm or more.

In the image forming material of the present invention, an antioxidant may be contained in the microcapsules in order to further impart stability before use. As the antioxidant, a phenol compound, a hydroquinone compound, a catechol compound and the like are preferable. Specific compounds of the antioxidant include 2,6-di-t-butyl-4-methylphenol, 2,4,6-tri-t-butylphenol,
2,5-di-t-butylhydroquinone, 2,3-di-
Examples thereof include t-butyl hydroquinone, 2,5-di-t-octyl hydroquinone, 2,5-di-t-amyl hydroquinone, and 3,6-di-t-butyl catechol.

In producing the image-forming material of the present invention, the photo-oxidizing agent and the antioxidant are used in a molar ratio of 10: 0.001 to
It is preferable to mix them in a ratio of 10: 2, particularly 10: 0.01 to 10: 1.

Further, in the present invention, any known sensitizer may be added to the microcapsules.

The image-forming material of the present invention can be exposed to light to form an image and then subjected to heat treatment to reliably obtain a stable image. That is, the fixing mechanism of the image forming material of the present invention is such that the photooxidizing agent and the reducing agent come into contact with each other through the microcapsule wall by heating, and the reducing agent acts and oxidizes even if the photooxidizing agent is subsequently activated. This is because the agent is inactivated and the leuco dye no longer develops color. Such a reducing agent acts as a so-called free radical scavenger that traps the free radicals of the activated photo-oxidizing agent.

Examples of the reducing agent in the present invention include:
JP-A-2-44 discloses a hydroquinone compound having a hydroxyl group on a benzene ring and at least another hydroxyl group or an amino group at another position of the benzene ring, an aminophenol compound, a cyclic phenylhydrazide compound, and further guanidine. A compound selected from a derivative, an alkylenediamine derivative and a hydroxyamine derivative, a phenylhydrazine compound or the like can be used. Specific examples of the reducing agent include hydroquinone, catechol, resorcinol, hydroxyhydroquinone, pyrrologricinol, aminophenol, 1-phenylpyrazolidin-3-one (phenidone A), 1-phenyl-4-methyl. Pyrazolidin-3-one (phenidone B), 3-methyl-1- (p-sulfophenyl) -2-pyrazolin-5
-One, 3-methyl-1-phenyl-2-pyrazoline-
5-on and the like can be mentioned.

In the image-forming material of the present invention, the reducing agent is not encapsulated in microcapsules but is solid-dispersed by a sand mill or the like, or is dissolved in oil and emulsified and dispersed. When solid-dispersing or emulsifying, it is preferred to use protective colloids similar to those mentioned above for the preparation of microcapsules. The amount of the reducing agent is preferably 1 to 100 times, and more preferably 5 to 20 times the molar amount of the photooxidant component.

The fixing of the image in the present invention can be effectively achieved by contacting the photo-oxidizing agent and the reducing agent through the capsule wall by heating as described above, but it is synergistic by simultaneously performing heating and pressurization. You can also expect a great effect. It is preferable to use a melting point depressant such as p-benzyloxyphenol or p-toluenesulfonamide together with this reducing agent because fixing can be performed at a relatively low temperature.

The image-forming material of the present invention can be produced in the same manner as the method described in JP-A-2-44, except that the above xanthene derivative is used as the leuco dye.

That is, the image-forming material in the present invention can be prepared by coating on a support as a dispersion of microcapsules containing the above-specified leuco dye and a photo-oxidizing agent and a reducing agent.

Binders, pigments, waxes, metal soaps or surfactants may be further added to the dispersion of the microcapsules containing the leuco dye and the photo-oxidizing agent and the reducing agent. The coating amount of the image forming layer in the invention is
3 to 30 g / m ^{2 in} terms of solid content, especially 5 to 20 g / m ²
Is preferred.

Suitable materials for the support include, for example, papers from tissue paper to thick ball paper, recycled cellulose, cellulose acetate, cellulose nitrate.
Examples thereof include films of polymers such as polyester, polyethylene terephthalate, polyethylene, polyvinyl acetate, polymethyl methacrylate, polyvinyl chloride and the like.

The coating solution for the image-forming layer is applied to the support by an air-knife coat method, a carten-coat method,
Slide coating method, roller coating method, dip coating method, wire bar coating method, blade coating method, gravure coating method, spin coating method or extrusion coating method. However, the method is not limited to these.

If desired, an undercoat layer may be provided on the support or a coating layer may be provided on the image forming layer. The undercoat layer and the coating layer are mainly composed of a binder and / or
Or it contains a pigment.

The method of forming an image using the image forming material of the present invention and fixing the obtained image is the same as the method described in JP-A-2-44. Imagewise exposure to the imaging element of the present invention may be accomplished, for example, by writing with a beam of activating light or by exposing a selected area of a negative, stencil or other relatively opaque pattern to a suitable light source (eg, fluorescent light). Lamp, mercury lamp, metal halide lamp, xenon lamp, tungsten lamp, etc.)
Can be used for exposure. As a result, the photo-oxidant is activated and a leuco dye image is formed. The fixing of the formed image is performed by heating the temperature of the wall material of the microcapsule to a temperature above its glass transition temperature and contacting the photooxidizing agent and the reducing agent through the wall of the capsule. You can On this occasion,
You may pressurize simultaneously.

The image-forming material of the present invention is used as an image-forming material with improved background light yellowing and powder blowing.

[0050]

EXAMPLES Examples will be shown below, but the present invention is not limited thereto. In addition, "part" which shows an addition amount shows "weight part.

[Example 1] 9- (2-Methoxycarbonylphenyl) -2- (2,4-dimethylphenyl) amino-3-methyl-6-diethylaminoxanthene [leuco dye] 1 part, 2,2'- Bis- (o-chlorophenyl) -4,4 ', 5,5'-tetraphenylbiimidazole [photooxidant] 2 parts, tribromomethylphenyl sulfone 0.4 part, 2,6-di-t-octylphenol 0 1 part and 10 parts of a 75 wt% ethyl acetate solution of xylylene diisocyanate / trimethylolpropane adduct, 16 parts of ethyl acetate and 1 of dicyclohexyl phthalate.
It was added to 4 parts of mixed solvent and dissolved. This solution was added to a 5 wt% aqueous solution of carboxy-modified polyvinyl alcohol 64
Part, and emulsified and dispersed at 20 ℃, average particle size 1μm
To obtain an emulsion. 58 parts of water was added to the obtained emulsion and 4
Stirring was continued for 3 hours at 0 ° C. Then return to room temperature,
Filtration gave a capsule dispersion.

Next, 9.4 parts of 1-phenylpyrazolidin-3-one (phenidone A) [reducing agent] and 0.9 part of p-toluenesulfonamide were added to 23 parts of a 6% by weight aqueous solution of carboxy-modified polyvinyl alcohol. In addition to the above, the mixture was dispersed by a horizontal sand mill to obtain a reducing agent-containing dispersion liquid having an average particle diameter of 1 μm.

Next, a coating solution having the following composition was prepared. 165.4 parts of the above capsule dispersion 33.3 parts of the above Phenidone A dispersion 33.3 parts 20% silica (Cyroid 404, manufactured by Fuji Devison Chemical Co., Ltd.) dispersion 7 parts 30% epoxidized polyamide resin (FL-71, Toho Chemical ( Co., Ltd.) 3 parts 10% sulfosuccinic acid 4-methylpentyl ester aqueous solution 3 parts

This coating solution was applied to wood free paper (grammage 76 g / m ² ).
Was coated with a coating rod at a solid coating amount of 10 g / m ² and dried at 50 ° C. to obtain an image forming material.

[Embodiment 2] In the first embodiment, 9- (2-
Methoxycarbonylphenyl) -2- (2,4-dimethylphenyl) amino-3-methyl-6-diethylaminoxanthene Instead of 1 part 9- (2-diphenylmethyloxycarbonylphenyl) -2- (2,4-dimethyl) An image forming material was obtained in the same manner as in Example 1 except that 1.2 parts of (phenyl) amino-3-methyl-6-diethylaminoxanthene was used.

[Embodiment 3] In Embodiment 1, 9- (2-
Methoxycarbonylphenyl) -2- (2,4-dimethylphenyl) amino-3-methyl-6-diethylaminoxanthene 9- (2-methoxycarbonylphenyl) -2- (2,4,6-trimethyl) instead of 1 part An image forming material was obtained in the same manner as in Example 1 except that 1 part of (phenyl) amino-3-methyl-6-diethylaminoxanthene was used.

[Comparative Example 1] In Example 1, 9- (2-
1 part of 9- (2-methoxycarbonylphenyl) -2-anilino-6-diethylaminoxanthene instead of 1 part of methoxycarbonylphenyl) -2- (2,4-dimethylphenyl) amino-3-methyl-6-diethylaminoxanthene An image forming material was obtained in the same manner as in Example 1 except that was used.

The image forming materials obtained in Examples 1 to 3 and Comparative Example 1 were tested as follows. The results are shown in Table 1. (1) Image Density A fresh sample was irradiated with light through a line drawing original by a jet light (ultra high pressure mercury lamp, manufactured by Oak Co., Ltd.) to obtain a yellow image. Then, the unexposed portion was fixed by passing it through a heating roller at 135 ° C. at a speed of 450 mm / min. Then, the image density of the exposed portion was measured with a Macbeth reflection densitometer. (2) Hue of developed image (1) The hues of the images obtained by the evaluation of the image density were visually compared. In order to examine the hue when the leuco dye develops color by ordinary oxidation, the leuco dyes used in Examples and Comparative Examples were separately oxidized with chloranil in acetic acid, and all developed a dark green color. (3) Thermal Fixability (1) In the evaluation of image density, the sample that had been thermally fixed was irradiated with light over the entire surface, and the change in whether or not the non-image forming part developed a color was visually observed. (4) Stability of image area After the above heat-fixed sample was irradiated with a fluorescent lamp of 32000 lux for 10 hours, the density of the image area was measured with a Macbeth reflection densitometer, and the image density before irradiation with the fluorescent lamp was measured. Compared with.

[0059]

[Table 1]

As is clear from the data in Table 1, the image-forming materials of the present invention obtained in the respective examples are compared with the image-forming materials obtained in the respective comparative examples using the leuco dye outside the scope of the present invention. The density of the color image is high and the target black hue is obtained.

[0061]

The image-forming material of the present invention has the remarkable effect of providing a color image in which the density of a color-developed image is high and the stability of the color-developed hue is black.

Claims (2)

[Claims] 1. An image forming material comprising a support and a microcapsule containing at least an oxidative colorable leuco dye and a photooxidant, and a coating layer containing a reducing agent formed on a support, wherein the leuco dye is: General formula (1): (In the formula, R ¹ represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group or an aryl group, R ² represents an alkyl group, an alkenyl group, an alkynyl group or an aryl group, and R ³ represents an alkyl group, an aryl group. Represents a group or a halogen atom, R ⁴ represents an alkyl group or a substituted carbonyl group, R ⁵ represents a methyl group or a halogen atom, R ⁶ ,
R ⁷ and R ⁸ each independently represent a hydrogen atom, a methyl group or a halogen atom, and R ¹ and R ² are bonded to each other to form a ring which may contain an unsaturated atom or a hetero atom. The xanthene ring or the benzene ring bonded to the 9-position thereof may have one or more other identical or different substituents). 2. The image forming material according to claim 1, wherein an antioxidant is further contained in the microcapsules.