JPH10166725A - Multicolor recording method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for efficiently performing a multicolor recording process using a wide range of coloring materials to be selected from and with the help of a multicolor recording material with highly stable shelf life. SOLUTION: A recording material consists of a first recording layer containing a photodecolorizing element and a second recording layer containing a photocolor developing element, formed on a support. The photodecolorizing element of the first recording material is mixed using a first heat to form a first latent image, then the first latent image or an image other than the first latent image is decolorized using a light, and the photocolor developing element of the second recording layer is mixed using a second heat whose energy is higher than the first heat to form a second latent image. Finally, the color of the second latent image is developed using the light.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multicolor recording method using a heat-sensitive recording material provided with a recording layer which is decolored by irradiating light after heating, and a recording layer which is colored by irradiating light after heating. Things.

[0002]

2. Description of the Related Art In recent years, with the rapid development of the information industry, there is an increasing demand for obtaining a color hard copy easily and in a short time from a terminal such as a computer or a facsimile. Under these circumstances, various types of color hard copies have been marketed as products.However, a non-transfer type thermal recording method using a thermal head is a system that can obtain high-quality images with a simple recording apparatus. It has attracted attention because it has features such as high reliability, no noise at the time of recording, no maintenance, no running cost, and no waste material accompanying recording.

[0003] Various studies have been made to realize multi-color recording by a thermal recording method by taking advantage of this advantage.
In order to achieve multi-color recording by the thermal recording method, it is necessary to independently color recording layers having different thermal sensitivities.

As one of the means, Japanese Patent Application Laid-Open No. 61-40 / 1986
No. 192, using a diazo compound having a property of deactivating a coupling ability with a coupling agent when decomposed by light, each of the coloring layers is independently formed by decomposing the diazo compound remaining after heat recording with light. There has been proposed a heat-sensitive recording material of a type in which a color is formed to perform multicoloring (hereinafter, the heat-sensitive recording material is simply referred to as a recording material). However, since this recording material uses a diazo compound having poor thermal stability, it has a serious problem that the long-term storage decomposes the diazo compound and lowers the maximum color density.

Further, as a recording material which is made full color without using a diazo compound having poor heat stability, Japanese Patent Application Laid-Open No.
No. 43252 discloses a photosensitive and thermosensitive coloring layer comprising a microcapsule containing a oxidative coloring type leuco dye and a photo-oxidizing agent and a reducing agent (hereinafter referred to as a negative type coloring layer), an electron donating leuco dye and an electron accepting compound. A multicolor recording material provided with a thermosensitive coloring layer has been proposed. However, the negative-type photochromic layer of this recording material mixes the reducing agent outside the microcapsules with the photooxidizing agent inside the microcapsules by thermal recording, stops the color forming properties, and then exposes the entire surface to a non-photosensitive layer. This is a method of coloring the heating part (hereinafter referred to as negative light coloring). Since the oxidative coloring leuco dye and the photooxidant are mixed from the beginning, they are exposed to room light or sunlight during storage, There is a major drawback that the photooxidant is gradually decomposed during storage to cause fogging, and a multicolor recording material that can be handled more easily and that can withstand long-term storage has been demanded.

The present inventors have conducted intensive studies on a recording material which does not use a diazo compound having poor thermal stability and has improved fogging during storage, and as a result, a latent image is formed by being mixed by heat. A recording material comprising a light decoloring element for decoloring the latent image or a component other than the latent image by light; and a light which is mixed by heat to form a latent image, and the latent image is colored by light. It has been found that a recording material comprising a color-forming element has excellent storage stability without a decrease in the maximum color density or occurrence of fogging even during long-term storage.

[0007] In this light decoloring element, the heated portion or the non-heated portion is decolorized by light irradiation after thermal recording, and at the same time, the photosensitive material in the light decolorizable element is decomposed also in the non-heated portion or the heated portion. However, the decoloring reaction does not proceed due to the presence of a substance that is not in a mixed state or that suppresses the function of the decolorized product in decoloring. That is, fixing is performed simultaneously with decoloring by light irradiation. Further, in the light-coloring element, while the heated portion develops color by light irradiation after thermal recording, the photosensitive substance in the light-coloring element is decomposed in the non-heated portion, but the coloring reaction does not proceed because it is not in a mixed state. That is, fixation is performed simultaneously with color development and decoloration by light irradiation. If this property is used, multicolor recording is possible in principle.

In multi-color recording, in order to record a desired hue with care, it is necessary to incorporate a plurality of recording elements for recording in different hues on a support and record each recording element independently. is there. The present inventors have conducted intensive studies and found that, by combining the light decoloring element and the light coloring element, multicolor recording can be performed with a recording material having a wider range of color material selection and excellent storage stability. Was.

In order to take advantage of the above-mentioned recording material having an optical decoloring element and a light-color-forming element (hereinafter referred to as the present inventors' multicolor recording material) to realize good multicolor recording, light A recording method is required that can maximize the characteristics of the decoloring element and the light-coloring element. The multicolor recording material of the present inventors performs recording by heat and light. The present inventors have conducted intensive studies on a recording method using these recording materials and have reached the present invention.

[0010]

The problem to be solved by the present invention is that the present inventors have found that a multicolor recording material having a wider range of color material selections and excellent storage stability has been found to be favorable. An object of the present invention is to provide a method for performing multicolor recording.

[0011]

The problem to be solved by the present invention is that a first recording layer containing a photo-decolorizable element and a second recording layer containing a photo-color-forming element are provided on a support. A recording material provided, wherein a first latent image is formed by mixing the light decoloring elements of the first recording layer with first heat, and the first latent image or a component other than the first latent image is formed. Is decolorized by light,
The photochromic elements of the second recording layer are mixed by a second heat having an energy larger than the first heat to form a second latent image, and the second latent image is colored by light. And a multicolor recording method.

That is, in recording our multicolor recording material, heat is used to mix the isolated photobleachable elements and the isolated photochromic elements. The multicolor recording material of the present inventors has better storage stability than the conventional multicolor recording material as described above. This is because a compound having poor thermal stability such as a diazo compound is not contained, and a color-forming element such as an oxidative-color-forming leuco dye and a photo-oxidizing agent in negative-type photo-coloring is not mixed from the beginning. In order to take advantage of this advantage and obtain better multicolor recordings, we examined the storage stability under more severe storage conditions. We have found a difference. That is, the storage stability under a more severe storage condition was slightly better for the photo-decolorizable element than for the photo-color-forming element. The reason is considered as follows.

In more severe storage conditions, it is believed that some mixing of the isolated photochromic elements and some of the isolated photochromic elements occurs. In such a case, in the case of a type in which a latent image formed by mixing is erased (hereinafter referred to as a negative type), the mixing of a part of the optical decoloring element depends on the degree of mixing. It leads to the promotion of decoloration according to. However, this only slightly lowers the color density of the image portion after recording, and has almost no effect on the non-image portion. Further, in the case of a type in which a color other than the latent image formed by mixing is erased (hereinafter, referred to as a positive type), mixing of a part of the light-erasing element leads to suppression of color erasing according to the degree of mixing. This leads to coloring of the non-image portion after recording. However, the decoloring property can be controlled by the type and amount of the constituent elements of the decoloring element, and it is possible to avoid coloring the non-image portion. On the other hand, with respect to the light-coloring element, color mixing occurs depending on the degree of mixing due to mixing of a part of the light-coloring element, and coloring of the non-image portion is likely to occur, and control for avoiding this is difficult.

Therefore, in the multicolor recording using the multicolor recording material of the present inventors, in order to make the most of the good storage stability of the recording material, the mixing of the light-color-forming elements during severe storage must be performed by light. To make it less likely to occur than mixing of the decoloring elements, the photochromic elements should be designed so that they do not mix with the application of a small amount of thermal energy, i.e., the photochromic elements are mixed with heat having a higher energy than the photochromic elements. The present inventors have found that it is advantageous to record the data.

Hereinafter, the present invention will be described in detail.

The light decoloring element of the multicolor recording material of the present invention may be any element as long as it is mixed by heat to form a latent image, and the latent image or a portion other than the latent image is decolorized by light. Can be used.

First, the negative-type light decoloring element will be described. The negative type photo-decolorizable element of the present invention preferably comprises a compound which decomposes by light and a dye which decolorizes by reacting with a decomposition product thereof. A more specific embodiment of the negative-acting photobleachable element of the present invention is where the compound that decomposes by light is a photoradical generator, initially with the photoradical generator and dye separated. When heat is applied, the photo-free radical generator and the dye are mixed to form a latent image.Subsequently, the latent image is irradiated with light absorbed by the photo-free radical generator. Is decolorized to be substantially colorless, while the photo-radical generating agent and the dye are not in a mixed state except for the latent image, so that free radicals do not react with the dye and do not decolor the dye. In this way,
The dye disappears in the heated recording portion and remains in the non-heated recording portion, so that a negative image is formed with respect to the recorded image.

Next, the positive-type light decoloring element will be described. The positive type photo-decolorizable element of the present invention is preferably a compound that decomposes by light, a dye that decolorizes by reacting with a decomposition product thereof, and a compound that suppresses the reaction by which the decomposition product decolorizes the dye (hereinafter, referred to as a compound). , A discoloration inhibitor). A more specific embodiment of the positive-type photobleachable element of the present invention is where the compound decomposed by light is a photoradical generator, wherein the photoradical generator and the dye are initially mixed and These and the decolorizing inhibitor are separated from each other, and by heating, the photofree radical generator, the dye and the decolorizing inhibitor are mixed to form a latent image, and subsequently the photofree radical generator is formed. By irradiating the light absorbed by the generator, free radicals are generated in the latent image, but the colorlessization of the dye is suppressed due to the presence of the decolorizing inhibitor, and the colorlessness of the dye does not occur, whereas in the other than the latent image The generated free radicals cause the dye to be decolorized to a substantially colorless one. In this manner, the dye remains in the heated recording portion and the dye disappears in the non-heated recording portion, so that a positive image is formed with respect to the recorded image.

The dye and the photo-radical generator used in the photo-decolorizable element of the multicolor recording material of the present invention are capable of decoloring when irradiated with light absorbed by a photo-radical generator, ie, substantially decolorized. It can be used in combination with a dye capable of converting into a compound that does not absorb light in the visible light region and a photo-free radical generator.

Examples of the dye include an azo dye, an azomethine dye, a polyene dye, a polymethine dye, a quinone dye, an indigo dye, a diphenylmethane dye, a triphenylmethane dye, and a phthalocyanine dye. Specific examples include dyes described in "Dye Handbook", edited by Japan Color Materials Association, Kodansha. From among these, a selection can be made in consideration of the color tone, light decoloring property, fastness, cost, and the like. Among them, an azomethine dye is mentioned as a preferable dye. In particular, from the viewpoint of color tone and fastness, azomethine dyes used in conventional color photography, specifically, acylacetanilide derivatives, pyrazolone derivatives, pyrazolotriazole derivatives,
An azomethine dye obtained by an oxidative coupling reaction between a coupler such as a phenol derivative or a naphthol derivative and a color developing agent (p-phenylenediamine derivative) is preferred. Examples of preferred dyes are shown below, but are not limited thereto.

[0021]

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[0022]

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[0023]

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[0024]

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The photo-radical generating agent in the photo-decolorizing element of the multicolor recording material of the present invention is activated when light of a specific wavelength is absorbed, and decolorizes the dye. It decomposes to generate free radicals, and when activated by absorbing light, it extracts hydrogen free radicals from other molecules, and the light-absorbing compound itself and the molecules from which hydrogen, etc. are extracted are converted to free radicals. Including. Further, as the light absorbed when generating free radicals, light absorbed by dyes called so-called sensitizers can be used. However, in this case, the dye serving as a sensitizer preferably has no absorption in the visible region, and does not affect the image. Specific examples of the photo-free radical generator include, for example, JP-B-62-39728,
2,4,6-triarylimidazole dimer compound described in JP-B-63-2099, U.S. Pat.
No. 93, azide compounds such as benzoyl azide, benzoyl azide and 2-azido benzimidazole; and 3'-ethyl-1-methoxy-2-pyridothia described in U.S. Pat. No. 3,615,568. Pyridinium compounds such as cyanine perchlorate, 1-methoxy-2-methylpyridinium-p-toluenesulfonate, N-bromosuccinimide, tribromomethylphenylsulfone, diphenyliodonium salt, 2-trichloromethyl-5- (p-butoxystyryl) -1, 3,
Organic halogen compounds such as 4-oxadiazole, 2,6-bis (trichloromethyl) -4- (p-methoxyphenyl) -s-triazine, carbonyl compounds such as benzophenone, thioxanthone, anthraquinone, and benzoin ether; acylphosphine oxides Phosphorus compounds such as, azo compounds such as azobisisobutyronitrile, alkyl disulfide, organic sulfur compounds such as mercaptan,
And diazo compounds. The wavelength of the light for activating the photoradical generator can be selected in consideration of the ease of handling as a recording material, the availability of the light source to be used, and the cost. The ease of handling as a recording material may be limited, for example, if the photosensitive material is sensitively exposed to light having a wavelength similar to that of room light, because it has a problem in stability and must be handled in a dark room. In order to avoid such restrictions, it is preferable to use a region from ultraviolet to a part of visible light or infrared light. Among them, considering the strength of energy and the availability of light sources, etc.
It is preferable to use light in the range of 0 nm to 450 nm.
Preferred photo-free radical generators include carbonyl compounds such as anthraquinone and benzoin ether, phosphorus compounds such as acylphosphine oxide, and diazo compounds. Further, the spectral absorption maximum wavelength of the photo-free radical generator is also 25.
It is preferable to be in the range of 0 nm to 450 nm from the viewpoint of the generation efficiency of photoradicals and the like. Examples of preferred photo-radical generators are shown below, but are not limited thereto.

[0026]

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[0027]

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In the photo-decoloring element of the multicolor recording material of the present invention, the decolorizing inhibitor inhibits the decoloration by inhibiting the reaction between the photo-free radical generator and the dye. The decoloring suppression mechanism is
Although it is not clear, there are mechanisms such as capturing the photoradicals generated when the photoradical generator is activated, or causing the decolorized body to recolor by the reaction between the dye and the active photoradical generator. It is considered that the combination of the photo-free radical generator and the color erasure inhibitor changes the erasure suppression mechanism. Examples of the decoloration inhibitor used in the present invention include guanidines such as triphenylguanidine, tetramethylguanidine, dicyclohexylguanidine, and bis (2-
Ethylhexyl) amine, trioctylamine, diisopropylethylamine, amines such as N, N-dimethyldodecylamine, piperazine, pyrrolidine, hindered amine, 2,5-di-ter-octylhydroquinone, 2,5-di-sec-dodecylhydroquinone And other mercaptans such as p-dodecyloxythiophenol, 2-mercaptobenzimidazole and 2-mercaptobenzothiazole, 2,6-di-ter-butylphenol, and 4,4'-butylidenebis (6-ter-butyl). -M-cresol), phenols such as hindered phenol, hydrazines, reducing agents such as phenidone and ascorbic acid, but are not limited thereto. Among these, preferred color erasure inhibitors include guanidines, amines, and phenols. Preferred examples of the decolorization inhibitor are shown below, but are not limited thereto.

[0029]

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In the photo-decolorizable element of the multicolor recording material of the present invention, the dye and the photo-radical generator are separated in the negative type, and the dye and the photo-radical generator are mixed in the positive type. And the decolorizing inhibitor are isolated. this house,
The use of a positive-type photo-decolorizable element is preferable in that the resulting image is all positive with respect to the thermal image, so that the apparatus and software can be simplified. As a separable method that can be used, for example, the components can be prevented from being uniformly mixed by solid dispersion or emulsification dispersion. In order to more surely isolate the components, the components to be isolated during storage can be applied separately to another layer on the support. It is also effective to provide an intermediate layer between each layer. A more preferred form is to use microcapsules. Preferred microcapsules in the present invention are those which prevent the contact of substances inside and outside the capsule at normal temperature due to the substance isolating action of the microcapsule wall, and increase the permeability of the substance when heated at a certain temperature. The temperature-dependent permeability of the microcapsules can be controlled by changing the glass transition temperature of the capsule wall depending on the capsule wall material, core substance, additive type and the like. As the wall material of the microcapsules that can be used in the present invention, polyester, polycarbonate, polyurethane,
Examples include polyurea, polyamide, polyether polycarbonate, urea-formaldehyde resin, melamine-formaldehyde resin, polystyrene, styrene-methacrylate copolymer, gelatin, polyvinylpyrrolidone, and polyvinyl alcohol. A plurality of these wall materials may be used. In the present invention, among the wall materials, polyurethane, polyurea, polyamide, polyester,
Polycarbonate and the like are preferable, and polyurea and polyurethane are particularly preferable. Details of the microcapsules that can be preferably used in the present invention are described in the specification of US Pat. No. 3,796,696. The microcapsules used in the present invention are preferably prepared by emulsifying a core substance containing a substance to be encapsulated, and then forming a wall of a polymer substance around the oil droplets to form a microcapsule. . At that time, it is preferable to use an organic solvent to form emulsified oil droplets as necessary, and the organic solvent to be used can generally be appropriately selected from high-boiling organic solvents. For example, phosphoric acid esters, phthalic acid esters, acrylic acid esters, methacrylic acid esters and other carboxylic acid esters, aliphatic amides, alkylated biphenyls, alkylated terphenyls, chlorinated paraffins, alkylated naphthalenes, diarylethanes and the like are used. . More specifically,
No.-242094 and those described in JP-A-62-75409 can be used. In addition to the above-mentioned high-boiling organic solvents, low-boiling solvents such as ethyl acetate and methylene chloride can be used in combination as solubilizers. On the other hand, the water layer mixed with the oil layer can contain a water-soluble polymer as a protective colloid, and for example, polyvinyl alcohol, gelatin, and a cellulose derivative can be used. When emulsifying and dispersing, an appropriate surfactant can be selected from known surfactants to prevent precipitation and aggregation. Other decoloring elements to be provided outside the microcapsules may be dispersed by any of solid dispersion and emulsion dispersion.

In the photo-decoloring element of the multicolor recording material of the present invention, the amount of the dye, photo-free radical generator and decoloring inhibitor used is not particularly limited, but is applied on a support. The thickness is selected in consideration of the film thickness, the decoloring suppression efficiency, the color density, and the like. The amount of the dye used is preferably 1 × 10 ⁻⁵ mo
1 / m ² to 1 × 10 ^-2 mol / m ² , more preferably 5 ×
It is in the range of 10 ⁻⁵ mol / m ² to 1 × 10 ⁻³ mol / m ² . The amount of photo-radical generator used is preferably 0.5
The molar ratio is in the range of ５０50-fold mol, more preferably 1- to 10-fold mol of the dye. The amount of the decolorizing inhibitor used is preferably in the range of 0.1 to 100 moles, more preferably 1 to 30 times the moles of the photoradical generator. In addition, even when the film thickness when coated on the support is not particularly limited, in consideration of heat sensitivity and image sharpness, etc.
The dry film thickness is preferably in the range of 0.5 μm to 50 μm, and more preferably in the range of 1 μm to 20 μm.

The light-color-forming element of the multicolor recording material of the present invention can be used as long as a latent image is formed by mixing with heat and the latent image is colored by light. It preferably comprises a compound which decomposes by light and an element which develops a color by reacting with a decomposition product thereof.

Compounds decomposed by light include ultraviolet light,
Any compound that can be decomposed by light such as visible light or infrared light may be used, and examples include a compound called a photo-free radical generator and an azide compound. As a photo-free radical generator,
For example, JP-B-62-39728, JP-B-63-209
No. 9,2,4,6-triarylimidazole dimer compound; US Pat. No. 3,282,693
Azidobenzoxadiazole, benzoylazide, 2
Azide compounds such as azidobenzimidazole, 3'-ethyl-1- according to U.S. Pat. No. 3,615,568;
Methoxy-2-pyridothiacyanine perchlorate, 1
Pyridinium compounds such as -methoxy-2-methylpyridinium-p-toluenesulfonate, N-bromosuccinimide, tribromomethylphenylsulfone, diphenyliodonium salt, 2-trichloromethyl-5-
(P-butoxystyryl) -1,3,4-oxadiazole, 2,6-bis (trichloromethyl) -4- (p-
Organic halogen compounds such as methoxyphenyl) -s-triazine, carbonyl compounds such as benzophenone, thioxanthone and benzoin ether; azo compounds such as azobisisobutyronitrile; alkyl disulfide;
Organic sulfur compounds such as mercaptan, and phosphorus-based compounds such as triphenylphosphine are exemplified.

The compound decomposed by light is decomposed by light, and then reacts with the decomposition product to form a color by reacting with a color-forming element to form a dye. In this case, the decomposition product is one of the generated dyes The compound may be a part of the compound, or may be changed to a compound different from the dye only by participating in the dye formation reaction. It is determined by the combination of a compound that decomposes by light and an element that develops a color by reacting with its decomposition product, but is selected in consideration of the production efficiency, color tone, robustness, absorption coefficient, etc. of the dye produced by the reaction. .

Various reactions can be used as the reaction of the present invention for producing a coloring dye by reacting with a photodegradable compound and a decomposition product thereof, but the reaction is preferably represented by the following formula (8). There are three types.

[0036]

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(In the above reaction formula, A represents a photodegradable compound, A ′ represents a photolysis product, and B, C, D
Represents an element which develops a color in response to A '. D ', B
-C and AC represent the generated coloring pigment. B 'is a form in which B is changed by the reaction with A'. The above reaction formulas are schematic representations of each type,
It is useful for understanding what the generated dye skeleton is derived from. In the above reaction formula, the element which forms a color by reacting with A 'is described as being composed of a single compound (types 1 and 3) or composed of two types of compounds (type 2). It may consist of more than one type. Also,
Auxiliary components (eg, bases and acids) that promote the dye-forming reaction are not described, but may be included in the photochromic element. That is, in the case of the type 1, the photodegradation product of A and the reaction of D generate D by oxidation, decomposition, and the like, thereby forming a coloring pigment. The basic skeleton of the coloring pigment is derived from D.

In the case of type 2, after one of the coloring elements B is activated by a certain change (for example, oxidation or decomposition) by the reaction with A ', the C of the other coloring elements is activated. (For example, a coupling reaction) to form a coloring pigment, and the basic skeleton of the coloring pigment is B or C
Derived from

In the case of the type 3, the colorant is formed by reacting A 'and C (for example, a coupling reaction). Unlike the type 1, the basic skeleton of the formed colorant is A and Derived from C.

As an example of the type 1, the compound decomposed by light is a photo-radical generator such as a 2,4,6-triarylimidazole dimer compound or an organic halogen compound, and the decomposition product is There are cases where the reacting element is a leuco dye. In this case, the decomposition products generated by light irradiation are imidazolyl free radicals and halogen free radicals,
Has strong oxidizing power. Utilizing the oxidizing power, for example, a leuco dye can be oxidized into a coloring pigment. As leuco dyes that can be used, for example, those described in U.S. Pat. No. 3,445,234 can be used. Typical structures include the following.

1) aminotriarylmethane 2) aminoxanthene 3) aminothioxanthene 4) amino-9,10-dihydroacridine 5) aminophenoxazine 6) aminophenothiazine 7) aminodihydrophenazine 8) aminodiphenylmethane 9) leucoin Damine 10) aminohydrocinnamic acid (cyanomethane, leucometine) 11) hydrazine 12) leucoin digoid dye 13) aminodihydroanthraquinone 14) 4,4'-biphenol 15) 2- (p-hydroxyphenyl) -4,5-diphenylimidazole 16) Phenethylaniline Specific examples of the compound include leuco crystal violet, tris (4-dimethylamino-o-tolyl) methane, bis (4-dimethylamino-o-tolyl) phenylmethane, Bis (4-dimethylamino-o-tolyl) thienylmethane, 2- (2-chlorophenyl) -amino-6
-N, N-dibutylamino-9- (2-methoxycarbonyl) phenylxanthene, 2-N, N-dibenzylamino-6-N, N-diethylamino-9- (2-methoxycarbonyl) phenylxanthene, benzo [ a] -6
-N, N-diethylamino-9- (2-methoxycarbonyl) phenylxanthene, benzoylleucomethylene blue, benzoyl-3,7-diethylaminophenoxazine, benzoyl-3,7-diethylamino-9-phenyldihydrophenazine, 6,6 ′ -Di-t-butyl-p, p'-bio-cresol;

Among these, preferred leuco dyes are triarylmethane leuco dyes such as tris (4-dimethylamino-o-tolyl) methane and benzoyl leucomethylene blue, benzoyl-3,7-diethylaminophenoxazine, benzoyl-3. And acylated leucoazine dyes such as 7,7-diethylamino-9-phenyldihydrophenazine. Examples of the photo-free radical generator used in combination with the above-mentioned leuco dye include 2,4,6-triarylimidazole dimer compound, tribromomethylphenyl sulfone, 2,6
And organic halogen compounds such as -bis (trichloromethyl) -4- (p-methoxyphenyl) -s-triazine. These photo-free radical generators can sensitize intrinsic sensitivity and spectral sensitivity by using various sensitizers in combination. As typical sensitizers,
For example, "Sensitizer", edited by Katsumi Tokumaru and Shin Okawara, Kodansha 198
The compounds described on pages 64-75 of the 7th year can be mentioned.

As an example of the type 2, the compound capable of decomposing by light is a photoradical generator having an oxidizing power similar to that of the type 1, and an element which reacts with the decomposition product to form a color is:
Examples include couplers and aromatic primary amines. For example, the generation of an azomethine dye by the oxidative coupling of an aromatic primary amine such as N, N-diethyl-p-phenylenediamine or 4-aminoantipyrine with a phenol or an active methylene compound is described in silver halide photography. As is well known in the field of photosensitive materials, the above-mentioned free radicals can be used to cause an oxidative coupling reaction to generate a dye. As the aromatic primary amine that can be used, other than the above-mentioned amines,
p-aminophenol, N, N-diethyl-2-methyl-p-phenylenediamine, N-ethyl-N-methanesulfonylaminoethyl-2-methyl-p-phenylenediamine, N, N-didodecyl-p-phenylenediamine And the like. Further, the above-mentioned aromatic primary amine is
If necessary, it can be used in the form of hydrochloride, sulfate, tosylate, perfluoroalkyl sulfonate, and the like. In addition, an acyl form, for example, an acetyl form, a benzoyl form, a p-toluenesulfonyl form, a (2,4-di-t-pentyl-phenoxy) acetyl form, and a p-dodecyloxyphenylsulfonyl form can also be used.
Among these, preferred aromatic primary amines include aminoantipyrine and perfluoroalkylsulfonic acid salts of N, N-dialkylamino-p-phenylenediamine derivatives.

As the coupler which forms a dye by oxidative coupling with an aromatic primary amine, those known in the field of silver halide color photographic light-sensitive materials can be used. Examples of couplers that can be used include U.S. Pat.
772, 162, 2,895,826, 3,0
02,836, 3,034,893, 2,47
4,293, 2,423,730, 2,36
7,531, 3,041,236, 4,33
No. 3,999, No. 2,600,788, No. 2,36
9,869, 2,343,703, 2,31
1,082, 3,152,896, 3,51
9,429, 3,062,653, 2,90
8,573, 2,875,057, 2,40
7,210, 3,265,506, 2,29
8,443, 3,048,194, 3,44
No. 7,928 and Agfa Mitteilung
en's Farbkuppler-eine Liter
atureberesicht, Vol. III, 112-1
It is described in representative patents and publications such as page 75 (1961). Among them, examples of preferable couplers include phenols, naphthols, pyrazolones, pyrazolotriazoles, acylacetanilides and the like. Further, both so-called 2-equivalent couplers in which a leaving group is substituted at the active site of the coupler and 4-equivalent couplers without active site substitution can be used. The reaction with the coupler may be accelerated by using a base, and a base may be used in combination as needed. As the base, an organic base such as triphenylguanidine, trihexylamine, pyridine, and quinoline, an inorganic base such as sodium hydrogen carbonate, potassium carbonate, and a metal salt of salicylic acid, and a metal salt of an organic acid can be used.

Examples of the type 3 include a case where the compound decomposed by light is an aromatic azide and an element which reacts with the decomposition product to form a color is a coupler.
When an aromatic azide compound is decomposed by light, nitrene is generated. The produced nitrene can produce an azomethine dye by the reaction with the above-mentioned coupler. Examples of the aromatic azide compound that can be used include, for example, 4- (N,
N-diethylamino) phenylazide, 2,5-dibutoxy-4-morpholinophenylazide, 2,5-dibutoxy-4-phenylthiophenylazide, 4- (N-ethyl-N-methylsulfonylaminoethylamino) -2
-Methylphenyl azide, 4-diethylamino-3-dodecyloxycarbonylphenyl azide, 1-naphthyl azide, 2-naphthyl azide, anthranyl azide, 3
-Quinoline azide, 9-acridine azide and the like can be used. Examples of preferred aromatic azides include p-dialkylaminophenyl azides. Examples of the coupler that forms a dye by coupling with an azide include those described above.

In the light-color-forming element of the multicolor recording material of the present invention, the element which develops a color by reacting with a compound decomposed by light and a decomposition product thereof must have all components uniformly mixed before heating. There is no. At least one of a compound which decomposes by light and an element which develops a color by reacting with a decomposition product thereof;
The types of components need to be isolated by some means before heating. Such an isolation method requires isolation that does not cause a color reaction even if a compound decomposed by light is partially decomposed during storage. As the available isolation method, the same methods as those mentioned as the isolation method for the photo-decoloring element can be used. Among them, the method using microcapsules is used for the degree of isolation, the reactivity of color development, and the raw storage. Most preferred in terms of properties and the like. As for the wall material of the microcapsule, the preparation method, and the solvent, the same ones as described in the light decoloring element can be used.

In the photochromic element of the multicolor recording material of the present invention, a compound which decomposes by light is heated and reacts with the decomposition product to cause a color reaction at a site mixed with the element which forms a color. In the heating section, that is, in a portion separated from an element that develops a color by reacting with a decomposition product, no color reaction occurs even when irradiated with light. Preferably, when the non-heated portion is exposed to light, the compound that decomposes by light decomposes and changes into a substantially harmless compound by reacting with the surrounding compounds without participating in the color-forming reaction.

In the photochromic element of the multicolor recording material of the present invention, the amount of the compound decomposed by light and the element which reacts with the decomposition product to form a color is not particularly limited. The thickness is selected in consideration of a film thickness, a coloring efficiency, a coloring density, and the like at the time of coating on the top. The preferable use amount of any component is 4 × 10 ⁻⁴ mol / m ^{2 to} 6 × 10
^-3 mol / m ² . Further, the film thickness when coated on the support is not particularly limited,
In consideration of heat sensitivity and sharpness of an image, the dry film thickness is preferably in the range of 0.5 μm to 50 μm,
More preferably, it is in the range of m to 20 μm.

The multicolor recording material of the present invention can be prepared by coating a recording layer comprising a light-erasing element and a recording layer comprising a light-coloring element on a support. At this time, as a binder of the dispersion, polyvinyl alcohol, gelatin,
Various emulsions such as styrene-butadiene latex, carboxymethylcellulose, gum arabic, polyvinylpyrrolidone, polyvinyl acetate, and polyacrylate can be used, and the amount used is 0.5 g / m ^{2 to} 5 g / m ² in terms of solid content. m ² .

In the multicolor recording material of the present invention, it is preferable to provide a protective layer in consideration of image protection, prevention of adhesion between recording materials, prevention of adhesion to a thermal head, brushability, smoothness, and the like. As the binder for the protective layer, a known binder can be used. For example, methylcellulose, carboxymethylcellulose, hydroxymethylcellulose, starches, gelatin, gum arabic, casein, styrene-maleic anhydride copolymer hydrolysate, polyvinyl alcohol, carboxy-modified polyvinyl alcohol, polyacrylamide derivatives, polyvinylpyrrolidone, sodium polystyreneate , Sodium alginate, styrene-butadiene latex, acrylonitrile-butadiene rubber latex, polymers such as polyvinyl acetate emulsion, silicone resin, melamine resin,
A binder such as phenol resin, acrylic resin, polyester resin, epoxy resin, fluororesin, nitrocellulose, cellulose acetate propionate, cellulose acetate, fluorinated vinylidene resin, and chlorinated rubber can be used. As fillers for the protective layer, zinc oxide, calcium carbonate, barium sulfate, titanium oxide, lithobon,
Talc, pyroxene, kaolin, aluminum hydroxide, amorphous silica, inorganic pigments such as colloidal silica, polystyrene, polymethyl methacrylate, polyethylene, vinyl acetate resin, vinyl sulfide resin, vinylidene sulfide resin, styrene-methacrylate copolymer, Organic pigments such as vinylidene chloride, polyurea, and melamine-formaldehyde; metal soaps such as zinc stearate, calcium stearate, and aluminum stearate; or paraffin wax, microcrystalline wax, carnauba wax, methylol stearylloamide, polyethylene wax, and silicone. Waxes can be added. These fillers may be used alone or in combination of two or more.

When the multicolor recording material of the present invention is applied on a support such as paper or a synthetic resin film, a generally well-known coating method can be used. For example, it can be applied by a dip coating method, an air knife coating method, a curtain coating method, a roller coating method, a doctor coating method, a wire bar coating method, a slide coating method, a gravure coating method, a spin coating method or an extrusion coating method. it can.

Examples of the support that can be used in the multicolor recording material of the present invention include papers, films such as regenerated cellulose, cellulose acetate, cellulose nitrate, polyethylene terephthalate, polyethylene, polyvinyl acetate, and polyethylene naphthalate, glass, and the like. Wood, metal and the like.

As the light source that can be used in the present invention, various light sources that emit light having a wavelength capable of decomposing a compound decomposed by light can be used. For example, various fluorescent lamps, mercury lamps of various pressures, halogen lamps, xenon lamps, A tungsten lamp or the like can be used. Light for decoloring the first latent image or other than the first latent image (hereinafter, referred to as first light),
And the wavelength of light for forming the second latent image (hereinafter referred to as second light) is controlled by a method using light sources having different main emission wavelengths, a method of cutting unnecessary wavelengths by an optical filter, and the like. can do. Further, as the recording light decoloring element of the multicolor recording material of the present invention,
250 nm to 450 which is the preferable wavelength range described above.
Since there are various types having a good decoloring effect in a long wavelength region in the nm region, it is preferable to use light having a longer wavelength than the second light as the first light.

In the present invention, as the heat source of the first heat and the second heat, the mixture of the isolated photo-decoloring elements and the mixture of the isolated photo-developing elements are performed in an image-like manner to be recorded. For example, a heat pen, a thermal head, a heat stamp, a near-infrared laser beam, or the like can be used. When a near-infrared laser beam is used as a light source, a known infrared absorber such as a phthalocyanine derivative or a nickel complex may be contained.

In the present invention, when the light decoloring element contained in the first recording layer is a negative type, the first recording layer is colored from the beginning. When heat is applied to the recording layer, the isolated optical decoloring elements are mixed to form a latent image, and the latent image is decolorized by light irradiation. That is, since the color of the heated recording portion is erased and the coloring of the non-heated recording portion remains, a negative image is formed with respect to the recorded image. If the magnitude of the heat energy applied to the recording layer is gradually changed, the decolorization will not occur if the amount of heat energy is large because no mixing of the isolated optical decoloring elements will occur and no latent image will be formed. The initial coloring density, that is, the maximum density is almost maintained without occurrence. When the heat energy reaches a certain size and a latent image is formed, the erasing proceeds in accordance with the heat energy, and the image density decreases. When the heat energy is further increased, the decoloring of the image portion does not proceed any more and reaches the minimum density. With the heat energy higher than that, the image density hardly changes and the minimum density is maintained.

In the present invention, even when the light decoloring element contained in the first recording layer is a positive type, the first recording layer is colored from the beginning. When heat is applied to this recording layer, the isolated optical decoloring elements are mixed to form a latent image, and the other image is decolorized by light irradiation. That is, since the unheated recording portion is decolorized and the heated recording portion remains colored,
A positive image is formed for the recorded image. When the magnitude of heat energy applied to the recording layer is gradually changed,
At a certain level of heat energy, mixing of isolated photo-decoloring elements does not occur and no latent image is formed, so that decoloring occurs and density cannot be obtained, and the minimum density is maintained. When the heat energy reaches a certain size and a latent image is formed, decoloring is suppressed in accordance with the heat energy, and the image density increases. When the heat energy further increases, the image density reaches the maximum, and when the heat energy exceeds that, the image density does not change and almost the maximum density is maintained.

In the present invention, the light-coloring element of the second recording layer containing the light-coloring element is not colored at first. When heat is applied to the recording layer, the isolated light-coloring elements are mixed to form a latent image, and the latent image is colored by light irradiation. That is, a positive image is formed for the recorded image. When the magnitude of the heat energy applied to the recording layer is gradually changed, the color does not occur because the isolated light-coloring elements do not mix and the latent image is not formed when the heat energy is large. The lowest concentration is maintained. When the heat energy reaches a certain size and a latent image is formed, color development proceeds in accordance with the heat energy and the image density increases. When the heat energy further increases, the color density of the image portion reaches the maximum, and when the heat energy exceeds that, the image density hardly changes and the maximum density is maintained.

In the present invention, the energies of the first heat and the second heat are, for example, when a thermal head is used as a heat source, when the light decoloring element contained in the first recording layer is a negative type. The energy of the heat at which the image density of the second recording layer reaches the maximum density from the energy of the heat at which the image density of the first recording layer reaches the minimum density is defined as a recording energy per unit area of 5 mJ / mm ^{2 to} 100 mJ / mm. ⁽² ) It is preferable to increase the value of 10 mJ / mm ^{2 to} 60 mJ / mm ^2.
More preferably, it is increased. Further, when the light decoloring element contained in the first recording layer is of a positive type, the image density of the second recording layer is the maximum density from the heat energy at which the image density of the first recording layer reaches the maximum density. Energy of heat reaching 5 mJ / mm as recording energy per unit area
^{2 to} 100 mJ / mm ^2, preferably 10 m
It is more preferable to increase J / mm ^{2 to} 60 mJ / mm ² .

In the present invention, the energy of the first heat and the energy of the second heat can be controlled by, for example, changing the electric energy applied to the thermal head when the thermal head is used as a heat source. Specifically, this is performed by changing the voltage applied to the thermal head or by changing the time for applying the voltage. The latter is more general.

The evaluation results of the storage stability under severe conditions of the photo-decolorable element and the photo-color-forming element discovered by the present inventors are shown below. “Parts” indicating the amount of addition indicates “parts by weight”.

[Preparation of Photobleachable Sample 1] 1.5 parts of dye D-1 (molar extinction coefficient = about 18,000), 3 parts of photoradical generator P-13, 10 parts of ethyl acetate, Phenyl-1
-Dissolved in 10 parts of xylylethane, and added 8.0 parts of xylylene diisocyanate / trimethylolpropane adduct. This solution is treated with a 6% aqueous polyvinyl alcohol solution 6
0 parts, and emulsified and dispersed at 20 ° C. using a homogenizer to obtain an emulsion having an average particle size of 1 μm. 20 parts of water was added to the obtained emulsion, and stirring was continued at 40 ° C. for 3 hours. Thereafter, the temperature was returned to room temperature to obtain a capsule liquid a.

Further, 30 parts of the decolorization inhibitor I-2 was added to 150 parts of a 4% aqueous polyvinyl alcohol solution, and dispersed by a sand mill to obtain a solid dispersion of the decolorization inhibitor having an average particle diameter of 1 μm.

The coating liquid obtained by mixing 5 parts of the capsule liquid a and 5 parts of the solid dispersion of the decolorizing inhibitor was coated on wood free paper with a wire bar, and the reflection density of the red part became approximately 1.0. It was applied and dried as described above to obtain a photo-decolorable sample 1.

[Preparation of Photo Decolorizable Sample 2]
The photobleaching sample 1 described above, except that the xylylene diisocyanate / trimethylolpropane adduct was changed to the tolylene diisocyanate / trimethylolpropane adduct.
In the same manner as in the above, a photo-decolorable sample 2 was obtained.

[Preparation of Photochromic Sample 1] 6 parts of 2,5-dibutoxy-4-morpholinophenylazide was added to ethyl acetate 5
And xylylene diisocyanate / trimethylolpropane adduct (20 parts). This was dissolved. This solution was added to 46 parts of an aqueous 8% phthalated gelatin solution, and 18 parts of water and 1 part of water were added.
Two parts of a 0% sodium dodecylbenzenesulfonate aqueous solution was added, and the mixture was emulsified and dispersed at 20 ° C. using a homogenizer to obtain an emulsion having an average particle size of 1 μm. Water 20 was added to the obtained emulsion.
And stirring was continued at 40 ° C. for 3 hours. Thereafter, the temperature was returned to room temperature to obtain a capsule solution b.

Further, 4 parts of 7-chloro-6-tert-butyl-3- (3-dodecylsulfonylpropyl) pyrazolo [3,2-c] triazole was dissolved in 1 part of tricresyl phosphate, and a 15% aqueous solution of gelatin was dissolved. 32 parts, 1
0% sodium dodecylbenzenesulfonate aqueous solution 5
And 30 parts of water, and ultrasonically dispersed to obtain a coupler dispersion.

A coating solution obtained by mixing 6 parts of the capsule solution b, 8 parts of the coupler dispersion, 2 parts of a 15% aqueous gelatin solution and 4.5 parts of water was coated on a high quality paper with a wire bar. Was applied and dried so that the coating amount of azide was 0.15 g / m ² , to obtain a photochromic sample 1.

[Preparation of Photochromic Sample 2] Photochromic Sample 1
In the above photochromic sample 1, except that the xylylene diisocyanate / trimethylolpropane adduct was changed to the tolylene diisocyanate / trimethylolpropane adduct.
In the same manner as in the above, a light-colored sample 2 was obtained.

[Coloring test] The recording energy per unit area of the sample obtained above was changed by changing the time for applying a voltage applied to the thermal head using a thermal printing tester using a thermal head. After heat recording, the entire surface was irradiated with light from a high-pressure mercury lamp for 10 seconds, and the reflection density of the hue of each dye was measured.

The recording energy at which the recording portion of each sample reaches the maximum density is the recording energy per unit area.
Photo-decoloring sample 1 and the light color sample 1, 35 mJ / mm ^2, was photo-decoloring sample 2 and the light color sample 2 60 mJ / mm ^2.

[Evaluation of Storage Stability] The above photo-decolorable sample 1,
The photochromic sample 1 was heat-recorded using the above-described thermal printing tester so that the recording energy per unit area was 35 mJ / mm ² , and was irradiated with light over the entire surface with a high-pressure mercury lamp for 10 seconds. Further, the photo-decolorable sample 2 and the photo-color developing sample 2 were heat-recorded so that the recording energy per unit area was 60 mJ / mm ^2, and then the whole surface was irradiated with a high-pressure mercury lamp for 10 seconds.

Each sample was left for 3 days at 80 ° C. under dry conditions, and then subjected to thermal recording and light irradiation in the same manner as described above.

The results of measuring the reflection density of the hue corresponding to each dye in the thermal recording area and the non-thermal recording area are shown below.

[0074]

[Table 1]

From the above results, there is little difference between the photo-decolorable sample and the photo-colored sample in the thermal recording section when the storage condition is severe. However, in the non-thermal recording area, the light-colored sample is more affected than the light-decolored sample, and the degree of this effect is smaller in the light-colored sample 2 than in the light-colored sample 1. The photochromic sample 2 is designed and manufactured such that the isolated photochromic elements do not mix unless a larger thermal energy is applied than the photochromic sample 1. For this reason, the degree of mixing of the light-coloring elements generated in the dry storage at 80 ° C. is smaller in the light-coloring sample 2 than in the light-coloring sample 1. The subsequent light irradiation causes color development in accordance with the degree of mixing of the light-coloring elements.
Coloring of the non-image area after storage in dry at ℃ C
It is considered that the photochromic sample 2 was smaller.
Accordingly, it is advantageous to design the photochromic elements so that they are not mixed by applying a small amount of thermal energy, that is, to mix and record the photochromic elements with heat having higher energy than the photochromic element.

[0076]

EXAMPLES Examples are shown below, but the present invention is not limited to these examples. “Parts” indicating the amount of addition indicates “parts by weight”.

[Preparation of Capsule Solution A] 1.5 parts of dye D-1 (molar extinction coefficient = about 18,000), 3 parts of photoradical generator P-13, 10 parts of ethyl acetate, 1 part of 1-phenyl- 1
-Dissolved in 10 parts of xylylethane, and added 8.0 parts of xylylene diisocyanate / trimethylolpropane adduct. This solution is treated with a 6% aqueous polyvinyl alcohol solution 6
0 parts, and emulsified and dispersed at 20 ° C. using a homogenizer to obtain an emulsion having an average particle size of 1 μm. 20 parts of water was added to the obtained emulsion, and stirring was continued at 40 ° C. for 3 hours. Thereafter, the temperature was returned to room temperature to obtain capsule liquid A.

[Preparation of Discoloration Inhibitor Solid Dispersion] A decolorization inhibitor I-2, 30 parts, was prepared by adding a 4% aqueous solution of polyvinyl alcohol 1
In addition to 50 parts, dispersed in a sand mill, average particle size 1μ
m of the decoloration inhibitor solid dispersion was obtained.

[Preparation of Coating Solution A]
Parts, and 5 parts of the above-mentioned decolorization inhibitor solid dispersion, were mixed,
I got

[Preparation of Capsule Solution B] 6 parts of 2,5-dibutoxy-4-morpholinophenylazide was added to ethyl acetate
Parts, 10 parts of diisopropylnaphthalene, and tolylene diisocyanate / trimethylolpropane adduct 2
10 parts were added. This was dissolved. This solution was added to 46 parts of an aqueous 8% phthalated gelatin solution, and 18 parts of water and 1 part of water were added.
Two parts of a 0% sodium dodecylbenzenesulfonate aqueous solution was added, and the mixture was emulsified and dispersed at 20 ° C. using a homogenizer to obtain an emulsion having an average particle size of 1 μm. Water 20 was added to the obtained emulsion.
And stirring was continued at 40 ° C. for 3 hours. Thereafter, the temperature was returned to room temperature to obtain capsule liquid B.

[Preparation of coupler dispersion] 7-chloro-6
-Tert-butyl-3- (3-dodecylsulfonylpropyl) pyrazolo [3,2-c] triazole (4 parts) is dissolved in tricresyl phosphate (1 part), and a 15% gelatin aqueous solution (32 parts) and 10% sodium dodecylbenzenesulfonate are dissolved. 5 parts of an aqueous solution and 30 parts of water were added and ultrasonically dispersed to obtain a coupler dispersion.

[Preparation of Coating Liquid B] The above capsule liquids B and 6
Parts, 8 parts of the above coupler dispersion, 15% aqueous gelatin solution 2
And 4.5 parts of water were mixed to obtain a coating liquid B.

[Coating] The coating solution B was coated on a high-quality paper with a wire bar, and the coating amount of azide in the coating solution B was 0.15 g / m ^2.
And dried. The coating solution A was applied thereon with a wire bar so that the reflection density of the red portion became approximately 1.0, and dried.

[Coloring Test] With respect to the obtained recording material,
Using a thermal printing tester that uses a thermal head, changing the time for applying a voltage applied to the thermal head, changing the recording energy per unit area, and performing thermal recording, then irradiating the entire surface with a high-pressure mercury lamp for 10 seconds. Then, the reflection density of the hue of each dye was measured. The recording energy at which the recording portion of the light decoloring element reached the maximum density was 35 mJ / mm ² as the recording energy per unit area, and the light coloring element did not develop color at this recording energy. The recording energy at which the recording portion of the light-coloring element reached the maximum density was 70 mJ / mm ² as the recording energy per unit area.

[Multicolor Recording] For the obtained recording material,
Using the thermal printing tester, thermal recording was performed so that the recording energy per unit area was 35 mJ / mm ² . At this energy, the decolorizing inhibitor in the coating solution A, the dye A, and the photoradical generator were mixed, and the azide compound and the coupler in the coating solution B were not mixed. That is, the light decoloring elements were mixed by the first heat.

Thereafter, the entire surface was irradiated with a high-pressure mercury lamp for 10 seconds using a filter that cuts light of 400 nm or less. The color of A disappeared. That is, colors other than the latent image of the light decoloring element were decolorized by the first light.

Next, the recording energy per unit area is 7
Thermal recording was performed so as to be 0 mJ / mm ² . At this energy, the azide compound and the coupler in the coating solution B were mixed. That is, the photochromic elements were mixed by a second heat having greater energy than the first heat.

Thereafter, when the entire surface was irradiated with a high-pressure mercury lamp using a filter that cuts light of 400 nm or more, the heat-recorded portion developed magenta and the non-heat-recorded portion did not change. That is, the latent image of the light-coloring element was colored by the second light having a shorter wavelength than the first light.

Thus, the portion recorded with both the first heat and the second heat is a mixed color of cyan and magenta, and the portion recorded only with the first heat is cyan and only the second heat. The recorded portion was magenta, and the portion not recorded by any of the first heat and the second heat was a white background having neither cyan nor magenta.

[0090]

As is clear from the examples, by using the multicolor recording method of the present invention, the present inventors have found that a wide range of color materials can be selected and a multicolor recording medium having excellent storage stability. Good multicolor recording could be performed with the recording material.

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Manabu Kaneko, Konica Corporation, 1 Sakuracho, Hino-shi, Tokyo In-house (72) Inventor Kenzo Nakazawa 1, Konica Corporation, Sakuracho, Hino-shi, Tokyo

Claims (2)

[Claims] 1. A recording material comprising a support and a first recording layer containing a light-decoloring element and a second recording layer containing a light-coloring element, wherein the first recording layer Mixing the light decoloring elements by a first heat to form a first latent image, and decoloring the first latent image or other than the first latent image by light,
The photochromic elements of the second recording layer are mixed by a second heat having an energy larger than the first heat to form a second latent image, and the second latent image is colored by light. Multicolor recording method. 2. The method according to claim 1, wherein the first decoloring element of the first recording layer is mixed by heat to form a first latent image, and the other color than the first latent image is decolorized by light. Item 8. The multicolor recording method according to Item 1.