JPS62181186A - Two-color type thermal transfer material - Google Patents

Abstract

PURPOSE:To record an ordinary paper with clear two-color images free of mixing of colors at the time of high-temperature transferring, by incorporating a decoloring agent into a thermally transferable ink, and chemically controlling the decoloring action of the decoloring agent by varying temperature. CONSTITUTION:A thermal transfer layer 3 provided on a base 2 of a thermal transfer material 1 comprises a layer 4 of a first thermally transferable ink comprising a coloring agent 4b dispersed in a heat-fusible binder 4a having a high melting point and a layer 5 of a second thermally transferable ink comprising a leuco dye 5b, a color developer 5c for the dye and a decoloring agent 6 having a relatively high melting point for inhibiting development of the color of the leuco dye, which are dispersed in a heat-fusible binder 5a having a low melting point. At the time of low-temperature transfer, the decoloring agent 6 does not display a decoloring action because it is not melted. At the time of high-temperature transfer, though the leuco dye 5b in the second ink layer 5 is brought into contact with the color developer 5c, the development of the color of the dye 5b is inhibited by the decoloring action of the melted decoloring agent 6. Accordingly, a clear transfer-recorded image 9b free of mixing of colors can be formed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a two-color layer thermal transfer material that can be recorded on plain paper and provides a clear two-color recorded image without color mixture during high-temperature transfer.

1. The thermal transfer recording method, which is one of the recording methods widely used in information processing systems, is generally a sheet-like support with heat-transferable colorants dispersed in a heat-melting binder. Using a heat-sensitive transfer material provided with an ink layer, this heat-sensitive transfer material is superimposed on a recording medium such that the heat-transferable ink layer is in contact with the recording medium, and the heat-transferable ink layer is selectively melted to form a recording medium. A transferred recorded image corresponding to the heat supply pattern is formed on the recording medium.

Such a thermal transfer recording method has conventionally been used to form a medium-color recorded image, but recently it is being studied as a method for recording multicolor images or full-color images.

As a technique for producing multiple colors, a heat-sensitive transfer material is used in which a layer of high-melting point ink and a layer of low-melting ink are sequentially provided on a support 1°, and the difference in melting point of these inks is calculated based on the ri. (Japanese Unexamined Patent Application Publication No. 148591/1982) to form a two-color recorded image by separating the functions of two ink layers using Technology using a heat-sensitive transfer material containing microencapsulated high-temperature color-forming dye in the layer (4 yen Kaisho 5
7-150600) has been proposed.

However, in these proposals, the color tone obtained during high-temperature transfer is given by a mixture of low-melting point ink and high-melting point ink (or high-temperature coloring dye), so a decrease in the clarity of the tone of the recorded image is unavoidable. Moreover, there is a drawback in that the color tone of the high melting point ink (or high temperature coloring dye) must be dark, such as black.

The technology that suppresses the mixing of color tones during high-temperature transfer is as follows:
A layer of high melting point ink, an intermediate layer consisting of a heat-melting binder, and a layer of low melting point ink that does not contain leuco dye and develops a color tone different from that of the high melting point ink are sequentially provided on the support. There is a proposal (Japanese Unexamined Patent Publication No. 167297/1983) using a heat-sensitive transfer material in which a high melting point ink contains a decoloring agent that inhibits color development of leuco dye.

However, in this case, there is a drawback that special coated paper coated with a color developer for leuco dye must be used as the recording medium. In addition, in this thermal transfer material, since the intermediate layer physically separates the leuco dye and decoloring agent, mixing of the leuco dye and decolorizing agent during high-temperature transfer is suppressed, and as a result, Suppression of color development of leuco dye by expression of decoloring effect during high temperature transfer (
In other words, the suppression of color tone mixing cannot be said to be sufficient.

The main object of the present invention is to provide a thermal transfer material that eliminates the above-mentioned drawbacks, can be recorded on plain paper, and provides a clear two-color recorded image that sufficiently suppresses color mixture during high-temperature transfer. Our goal is to provide the following.

As a result of research for the above-mentioned purpose, the present inventor found that even if a leuco dye and a decoloring agent come into physical contact, no decoloring effect occurs unless the decoloring agent melts, and In an embodiment using such a color erasing agent, it has been found that incorporating the color developer in the same thermal transferable ink layer as the leuco dye enables clear two-color recording on plain paper with IIT performance. .

The heat-sensitive transfer material of the present invention is based on these findings, and more specifically, includes a layer of a first heat-transferable ink formed by dispersing a colorant in a heat-melting binder on a support; -Blue colorant A second thermal transfer ink is prepared by dispersing a leuco dye that develops a different color tone and a color developer for the leuco dye in a thermofusible binder having a lower melting point than the aforementioned thermofusible binder. and a decoloring agent for suppressing color development of the leuco dye on at least one of the first or second thermal transfer ink, the layer being a decoloring agent for suppressing color development of the leuco dye, and a decoloring agent for suppressing color development of the second thermal transfer ink. It is characterized by containing a substance having a higher melting point than the meltable binder.

In the thermal transfer material of the present invention, even if the decolorizing agent in an unmolten state physically contacts the leuco dye, the electron-excessive portion in the decolorizing agent molecule (for example, the unshared electron pair on the oxygen atom)
and the electron-deficient portion (e.g., carbonium ion) in the leuco dye molecule generated by the action of the color developer. Since a ``solvated'' state is not substantially formed, it is presumed that no decolorizing effect due to the steric hindrance effect or ``cardiac donor'' effect of the decolorizing agent molecules occurs.

In the thermal transfer material of the present invention, since the decoloring agent is present in a position rather close to the leuco dye, the decoloring effect is smoothly and uniformly expressed simply by melting the decoloring agent. Color development of the dye is sufficiently suppressed.

Hereinafter, the present invention will be explained in more detail with reference to the drawings as necessary. In the following description, the amount-ratio is expressed in r%
``and 1 copy'' shall be referred to as ``TunS11ノ'' unless otherwise specified.

FIG. 1 is a schematic cross-sectional view in the thickness direction showing a final embodiment of the thermal transfer material of the present invention.

Referring to FIG. 1, a thermal transfer material 1 is formed by forming a thermal transfer layer 3 on a support 2, usually in the form of a sheet (used to include a film).

As the support 2, conventionally known films and papers can be used as they are; for example, films of relatively heat-resistant plastics such as polyester, polycarbonate, doliacetyl cellulose, polyamide, polyimide, cellophane or &L acid paper. , condenser paper, etc. can be suitably used. The thickness of the support 2 is 1 to 15 g when considering a thermal head as a heat source during thermal transfer.
It is desirable that the temperature be about 1 m, but there is no particular restriction when using a heat source that can selectively heat the thermal transfer layer 3, such as a laser beam. A heat-resistant protective layer made of silicone resin, fluororesin, etc. may be provided.

According to the invention, support 2! - Thermal transfer layer 3 is made of 1. 'The first thermal transfer ink layer 4 in which the coloring agent 4b is dispersed (this does not mean to exclude the dissolved state), the leuco dye 5b in the low melting point heat-melting paint 5a, and the leuco dye 5b in the leuco dye The second thermal transfer ink layer 5 is composed of a color developer 5c and a color erasing agent 6 having a relatively high melting point that suppresses color development of the leuco dye.

As the heat-melting binder, binders conventionally used in heat-transferable inks can be used as they are, but the melting point of the heat-melting binder 4a constituting the first heat-transferable ink layer 4 is 80 to 230°C Even 90~
200"O is preferable, and the melting point of the heat-melting binder 5a constituting the 52 heat transfer ink is 40-12
0°C, more preferably 50 to 100°C.

The melting point of the binder 4a is preferably 20 to 100°C, more preferably 30 to 80°C higher than the melting point of the binder 5a. If this difference in melting point is less than 30° C., especially less than 20° C., it becomes difficult to separate the functions of the first thermally transferable ink layer 4 and the second thermally transferable ink layer 5.

In addition, this specification: Substances that do not exhibit a fixed melting point in the fin (thermal melt binder, thermal transfer ink'v) D:!
JIS K 2406 JJL standard
The softening point determined by the six-ring and ball method is used instead of the melting point.

Examples of the heat-melting binder 4a or 5a include natural waxes such as spermaceti wax, beeswax, lanolin, carnauba wax, ganderilla wax, montan wax, and ceresin wax, petroleum waxes such as paraffin wax and microcrystalline wax, and dairy waxes. Waxes such as synthetic waxes, ester waxes, low-molecular J11 polyethylene, and synthetic waxes such as Fischer-Tropsch wax: or polyamide resins, polyester resins, epoxy resins, polyurethane resins, polyacrylic resins, and polyvinyl chloride. Resins such as resins, cellulose resins, polyvinyl alcohol resins, petroleum resins, and polystyrene resins; natural rubber,
Elastomers such as styrene-butadiene rubber, imprene rubber, and chloroprene rubber are preferably used.

Two or more types of the above-mentioned hot-melting binders may be used in combination as necessary, and this binder may also include
It is also possible to adjust the melt viscosity, adhesive force, degree of wood-philicity-hydrophobicity, etc. by adding additives such as plasticizers, oil agents, surfactants, etc.

If a surfactant having a property of increasing the affinity for either the first thermal transferable ink layer 4 or the second thermal transferable ink layer 5 is used, the first ink layer 4 and the second thermal transfer ink layer
This is preferable in terms of clear functional separation of the ink layer 5 and in making it easier to form the second ink layer 5 of the first ink layer 4I-.

In addition, from the point of view of improving the functional separation of the first thermal transferable ink layer 4 and the second thermal transferable ink layer 5, the melt viscosity at 140° C. of either the binder 4a or the binder 5a indicated in - at least 10 times the melt viscosity of the other binder (one binder has a melt viscosity of 140
'C! (including cases where it does not substantially melt or soften), and more preferably 15 to 100 times.

The first heat-transferable ink layer 4 is coated with a heat-melting binder 4a.
As the coloring agent 4b, for example, all known dyes commonly used in the printing and recording field such as carbon black, titanium black, phthalocyanine, and magnetite can be used. Two or more types may be mixed and used as necessary. The color tone of this coloring agent 4b is as follows.

The color tone differs from that of leuco-dyed nail i5b, which will be described later (
(including cases where only the shade is different) is sufficient, and colorant 4
There is no need to limit the color tone of b to a color tone darker than the color tone of the leuco dye 5b or a color tone of C color.

On the other hand, the leuco dye 5 constituting the second thermal transferable ink layer 5
b is defined as a colorless or light-colored electron-carrying organic substance that develops color by reacting with a color developer consisting of a female or electron-accepting substance.

As the leuco dye 5b, all leuco dyes known in the field of conventional thermosensitive recording paper, such as triphenylmethane, fluoran, phenothiazine, auramine, and spiropyran, can be used.

Examples of such leuco dyes 5b include the following.

3.3-bis(p-dimethylaminophenyl)-phthalide, 3.3-bis(p-dimethylaminophenyl)-6-dimethylamino 7-thalide (also known as crystal violet lactone), 3.3-bis(p-dimethylamino phenyl)-6-diethylamide/phthalide.

3.3-bis(p-dimethylaminophenyl)-6-chlorophthalide, 3,3-his(, p −'; butylaminophenyl)
Phthalide, 3-cyclohexylamino-6-chlorofluoran, 3-dimethylamino-5,7-dimethylfluoran, 3-diethylamino-7-chlorofluoran, 3-diethylamino-7-methylfluoran.

3-diethylamino-7,8-benzfluorane, 3-diethylamino-6-methyl-7-chlorofluorane, 3-(N-p-tolyl-N-ethylamino)-6-methyl-7-anilinoflurane orane, 3-pyrrolidino-6-methyl-7-anilinofluorane, 2-(N-(3'-1lifluoromethylphenyl)amine)-6-ethylaminofluorane, 2-(3,6 -His(diethylamino)-9-(O-chloroanilino)xanthylamine, 0. lactam), 3-diethylamino-6-methyl-7-(m-trichloromethylanilino)fluorane, 3-diethylamino-
7-(o-chloroanilino)fluoran, 3-dibutylamino-7-(o-chloroanilino)fluoran.

3-N-methyl-N-7mylamino-6-methyl-7-
7nylinofluorane, 3-N-methyl-N-cyclohexylamino-6-methyl-7-7nylinofluorane, 3-diethylamino-6
-Methyl-7-7nylinofluorane.

3-(N,N-diethylamino)-5-methyl-7-(
N,N-dibenzylamino)fluorane.

Benzoylleucomethylene blue, 6'-chloro-8'-methoxy-benzoindolino-pyrylosvirane, 6'-bromo-3-methoxy-benzoindolino-pyrylospirane, 3-(2'-hydroxy-4'-dimethylaminophenyl) -3-(2'-methoxy5'-chlorophenyl)phthalide, 3-(2'-hydroxy-4'-dimethylaminophenyl) -3-(2'-methoxy5'-nitrophenyl)phthalide, 3- (2'-Hydroxy-4'-diethylaminophenyl)-3-(2'-methoxy-5'-methylphenyl)phthalide, 3-(2'-methoxy-4'-dimethylaminophenyl)-3-(2'-'Hydroxy-4'-chloro-5'-
Methylphenyl) phthalide.

3-Morpholy/-7-(N-propyl-trifluoromethylanilino)fluorane.

3-pyrrolidino-7-trifluoromethylanilinofluorane, 3-diethylamino-5-chloro-7-(N-benzyl-trifluoromethylanilino)fluorane, 3-pyrrolidino-7-(di-p-chlorophenyl ) Methylamine fluoran, 3-diethylamino-5-chloro-7-(α-phenylethylamino)fluoran, 3-(N-ethyl-p-toluidino)-7=(α-phenylethylamino)fluoran, 3- diethylamino-
7-(o-methoxycarbonylphenylamino)fluorane, anilinofluothene, 3-diethylamino-7-chloroanilinofluorane, 3-dibutylamino-7-fluoroanilinofluorane, 3-diethylamino-5-methyl- 7-(α-phenylethylamino)fluorane, 3-diethylamino-7-piperidinofluorane.

2-chloro-5-(N-methyltoluidino)-7-(p
-nj thylanilino)fluoran.

3-(N-benzyl-N-cyclohexylamino)-5
, 6-penzo 7-α-naphthylamine-4'-bromofluorane.

3-diethylamino-6-methyl-7-mesitidino 4
',5'-benzfluorane etc.

The above-mentioned leuco dyes may be used alone, or may be used in combination of two or more as necessary to adjust the speed of coloring reaction, color tone, or durability of coloring. Good too.

The color developer 5C for the leuco dye 5b is the color developer 5C for the leuco dye 5b.
It is defined as an inorganic or organic substance that reacts with b and causes it to develop color.

As the color developer 5C, an acidic substance (Bronsted I%i) or an electron-accepting substance (Lewis acid) as described below is used, but an inorganic solid acid (for example, activated clay) or an organic acid (For example, phenolic resin, maleic acid resin) can also be used.

As the color developer 5C, for example, the substances listed below are used.

(a) Inorganic acids, organic acids boric acid, oxalic acid, maleic acid, tartaric acid, citric acid, succinic acid, benzoic acid, stearic acid, gallic acid, salicylic acid, l-hydroxy-2-naphthoic acid, O-hydroxyamino acid, 0. Fractional acid, m-hydroxyammonium, fragrant acid, 2-hydroxy-P-)ruyl acid, etc.

(b) Phenols 3.5-xylenol, thymol, p-tert-butylphenol, 4-hydroxyphenoxide, methyl-
4-hydroxybenzoate, 4-hydroxyacetophenone, α-naphthol.

β-naphthol, catechol, resorcinol, hydroquinone, 4-tert-octylcatechol.

4.4'-5ec-butylidenephenol, 2°2-dihydroxydiphenyl, 2.2'-methylenebis(4-
methyl-6-tert-butylphenol), 2.2'
-bis(4'-hydroxyphenyl)propane (also known as
Bisphenol A).

4.4'-isopropylidene-dos(2-tert-butylphenol), 4.4'-5ec-butylidene diphenol, pyrocalol, phloroglucin, phloroglucin carboxylic acid, etc.

(c) Thioureas N, N'-diphenylthiourea, N-P-ethylphenyl-N'-phenylthiourea J, N-p-f/l/phenyl-N'N-thunylthiourea, N.

N'-C-m-chlorophenylthiourea, N.

N'-p-coumelorophenylthiourea, N.

N'-di-m'-l-lifluoromethylphenylthiourea, N,N'-di-m-methylphenylthiourea, and the like.

On the other hand, the decolorizing agent 6 for the leuco dye 5b is defined as an electron-donating organic substance that participates in the coloring reaction of the leuco dye and suppresses its coloring.

As this color erasing agent 6, an organic compound having a lone pair of electrons in its molecule is usually used, but the melting point (T6) of the color erasing agent 6 is the melting point (T
5) Higher (T5<T.

) is necessary to control the decoloring effect M of the decoloring agent 6, and the difference in melting point between T6 and T5 is 10°C or more.
5. It is further preferable that the temperature is 20 to 50°C. T6 and T
If the difference in temperature is less than 10° C., it becomes difficult to suppress the decoloring action of the decoloring agent 6 when only the second ink layer 5 is melted or softened and transferred.

Further, by mixing the melted or softened color erasing agent 6 and the leuco dye 5b, the color erasing action of the color erasing agent 6 is quickly expressed, or the consumption of energy applied to the thermal transfer material 1 is suppressed. From the point "-T," is the first ink layer 4
below the melting point (T4) of the binder 4a, (T a≦T4
) is preferable.

As such a decoloring agent 6, for example, the compounds listed below are used.

(a) Higher aliphatic alcohols, such as stearyl alcohol, polypropylene glycol, pentamethylglycerin, and dimethylpentaglycerin.

(b) Polyether, polyethylene glycol derivatives such as polyethylene oxide, polyoxydecamethylene, trimethylene oxide, polyoxyethylene oleyl ether, polyoxyethylene cetyl ether, polyethylene glycol monostearate.

(c) Nitrogen-containing organic compounds such as acetamide, stearamide, phthalonitrile (di)alkylene oxide adducts of bisphenols Examples include compounds obtained by adding ethylene oxide (2.6 moles) to bisphenol A, bisphenol A compound obtained by addition-reacting A with ethylene oxide (6.0 mol) and propylene oxide (4.5 mol).

(e) Solubilized ethylene adduct of terephthalic acid For example, a compound obtained by adding ethylene oxide (2 mol) to terephthalic acid (1 mol).

(f) Morpholine compounds For example, 4,4'-dithiodimorpholine.

(g) Aliphatic amines such as stearylamine, behenylamine, distearylamine, )-n-dodecylamine, triethylenecyamine, octamethylenediamine, stearylgetanolamine.

In the present invention, from the viewpoint of quickly expressing the decoloring effect of the melted or softened decolorizing agent 6, the decolorizing agent 6 having a relatively low melt viscosity (for example, the melt viscosity at 140° C. is 1037 inches or less) is used. It is preferable to use one of the decolorizing agent 6 and the binder 4a of the second ink layer 4 more than the other from the viewpoint of suppressing the mixing of the decoloring agent 6 and the leuco dye 5b at relatively low temperatures. Make it hydrophilic (
For example, the decolorizing agent 6 is made more hydrophilic than the binder 4a)
It is preferable.

In the first thermal transfer ink made of the above-mentioned components, 1 to 400 parts of the colorant 4b are used per 100 parts of the heat-melting binder 4a.

On the other hand, in the second thermal transfer ink, 1 to 2 parts of leuco dye 5b was added to 100 parts of heat-melting binder 5a.
00 parts, developer 5C 2-400 parts, decolorizer 6 2-4
00 copies each are used.

1- The layer 4 of the first thermal transfer ink and the layer 5 of the second thermal transfer ink each have a weight of 1 to 10 gm, and more preferably 2 to 10 gm.
Preferably, the thickness is 8 gm.

In order to obtain the thermal transfer material 1 of the present invention, for example, a colorant 4b (further additives, fillers, etc., if necessary) is added to a heat-melting binder 4a constituting the first thermal transfer ink, and Melt and knead using a dispersion device such as a lighter, or
Alternatively, the mixture is kneaded with a suitable solvent and applied onto the support 2 to form the first thermal transfer ink layer 4.Then, the leuco dye 45b constituting the second thermal transfer ink layer 5 is applied. , a dispersion obtained by kneading the color developer 5C and the color erasing agent 6 separately with a solvent (for example, water) that is incompatible with the first thermal transferable ink layer 4 using a dispersion device such as a 7 tritor. The second ink layer 5 may be formed by mixing the liquid with a solution or dispersion of the heat-melting binder 5a and applying the mixture onto the first ink layer 4.

Next, thermal transfer recording method V using the thermal transfer material 1 described in lx
FIG. 2(a), FIG. 2(b), and FIG. 3(a), FIG. 3(b) are schematic cross-sectional views in the thickness direction of the support body showing typical embodiments of . This will be explained with reference to.

Referring to FIG. 2(a), on the thermal transfer layer 3 of the thermal transfer material 1, ? A recording medium 7 consisting of a sheet of paper or the like is placed facing each other.

Heat generated by the thermal head facing the support 2 side of the thermal transfer material 1 generates energy from the Niko 8 that melts or softens only the second thermal transferable ink layer 5 in a pattern according to the image signal. When supplied to the material 1, the heat-melting binder 5a of the second heat-transferable ink layer 5 is selectively melted or softened according to the pattern, and the leuco dye 5 in the ink layer 5 is melted or softened.
b comes into contact with the color developer 5C and develops color (similar to the color development in conventional thermal recording paper), but at this time, the color erasing agent 6 does not exhibit a color erasing effect because it is not melted or softened.

Therefore, the second ink layer 5, which has been melted or softened according to the pattern, is transferred to the recording medium 7 as shown in FIG. is formed.

On the other hand, referring to FIG. 3(a), an amount of energy to melt or soften both the first thermal transferable ink layer 4 and the second thermal transferable ink layer 5 in a pattern according to the image signal is applied in the same manner as above. When the leuco dye 5b in the second ink layer 5 is supplied from the heating element 8 to the thermal transfer material 1, the leuco dye 5b in the second ink layer 5 comes into contact with the color developer 5C. Color development is suppressed.

Therefore, the first ink layer 4 and the second ink layer 5 that have been melted or softened according to the pattern are as shown in FIG. 3(b).
As shown in , both have the color tone of the first ink layer 4 containing the colorant 4b by being transferred to the recording medium 7,
A clear transferred recorded image 9b without color mixture is formed.

In the following, basic embodiments of the thermal transfer material of the present invention have been described with reference to FIG.

In the present invention, depending on the characteristics of the leuco dye 5b, the decoloring agent 6, etc., in combination with the chemical control of the decoloring effect as described above (substantially inhibiting the decoloring effect during high-temperature transfer), It is also possible to use means for physically separating the leuco dye 5b and the decolorizing agent 6 (to the extent that this is not necessary).

FIG. 4 shows an example of the present invention when a multi-layer structure of thermal transferable ink is used as the physical isolation means, that is, when the leuco dye 5b and the decoloring agent 6 are contained in separate thermal transferable ink layers. FIG. 1 is a schematic cross-sectional view in the thickness direction of a thermal transfer material showing an embodiment.

Referring to FIG. 4, the first thermal transfer ink layer 4 is formed by dispersing a colorant 4b and a color erasing agent 6 in a heat-melting binder 4a, and the second thermal transfer ink layer 5 is formed by dispersing a coloring agent 4b and a color erasing agent 6 in a heat-melting binder 4a. It is made by dispersing leuco dye Hsb and color developer 5C in a meltable binder 5a.

In this case, when using higher aliphatic alcohol, higher aliphatic amide, etc. as the decolorizer 6, for example, the decolorizer includes
I: All or a part of the two heat-melting binder 4a can be used also.

Apart from this, it is also possible to use microcapsules as the physical isolation means described in +iif, that is, in the embodiment shown in Fig. 1, microcapsules (Fig. ) can also be used.

As described above, according to the present invention, the support E is provided with a layer of the 124th transferable ink made of a colorant dispersed in a high melting point binder, and a layer of leuco dye and a developer in a low melting point binder. A layer of a second thermal transferable ink having a coloring agent dispersed therein is provided in this order, and at least one of the first or second thermal transferable ink contains a color erasing agent. A thermal transfer material is provided.

By using the thermal transfer material of the present invention, the decoloring action of the decoloring agent can be chemically controlled by changing the temperature.
Clear two-color recorded images without color mixing during high-temperature transfer can be obtained on multiple sheets of paper.

Furthermore, when using the thermal transfer material of the present invention, there is no need for specially coated paper whose surface is coated with a color developer, and by omitting this specially coated paper, recording costs can be significantly reduced.

Hereinafter, the present invention will be explained in more detail with reference to Examples.

SifuLL (Formation of first thermal transferable ink layer) The resulting coating solution was applied onto a polyethylene terephthalate I film (thickness: 67 m) as a support using an applicator, and then dried to a dry thickness. A first thermal transferable ink layer of 3 gm was formed.

(Formation of second thermal transfer ink layer) Dispersion A Paraffin wax emulsion (T-7
30, manufactured by Hoechst) 100 parts (of which 66 parts solid content,
Solid content (melting point: 60°C) was added and mixed to form dispersion A to dispersion A1, dispersion B to dispersion B1, and dispersion C.
A dispersion liquid C1 was obtained from the following.

110 parts of dispersion A thus obtained, 40 parts of dispersion B
A second thermal transferable ink coating liquid obtained by mixing and stirring 100 parts, 0.120 parts of a dispersion, and 30 parts of water was coated on the first thermal transfer ink layer and dried to form a second thermal transferable ink layer with a dry thickness of 5 gm. 2
A heat-transferable ink layer was formed to obtain a heat-sensitive transfer material.

A commercially available word processor (Canoward CW-453, manufactured by Canon Inc.)
Attach it to the thermal head (4 mm x 4 mm for one character is 24
When pattern-like heat of 0°4 mJ/dot was applied from the support side using a 24-dot sample, a clear red recorded image due to the color development of the leuco dye was obtained on the plain paper serving as the recording medium.

Next, in the same way as above, when patterned heat of 0.7 mJ/dot was applied using a thermal head, a clear black recorded image without red color mixture was obtained, and extremely good color separation was obtained. Ta.

A red dye (Cele Red 3R, manufactured by Bayer) was used as the dye in the first thermal transferable ink layer of Example 1, and a black color-forming leuco m material (3-N-
Methyl-N-cyclohexylamino-6-methyl-7-
A heat-sensitive transfer material was obtained in the same manner as in Example 1 except that 7-nylinofluorane) was used.

When thermal transfer recording was performed using this thermal transfer material in the same manner as in Example 1, a clear black recorded image was obtained when thermal energy was applied at a rate of 0.4 mJ/dot, and a mixed color of black was obtained when thermal energy was applied at a rate of 0.7 mJ/dot. A clear red recorded image with no color was obtained, and extremely good color separation was obtained.

[Brief explanation of drawings]

1 to 4 are schematic cross-sectional views of the thermal transfer material as viewed in the thickness direction, and FIG. 1 shows a basic embodiment of the thermal transfer material of the present invention, and FIG. 4 shows another embodiment. Figures illustrating aspects, Figure 2(a), Figure 2(b), Figure 3(a), and Figure 3
Figure (b) is. FIG. 2 is a diagram for explaining the principle of two-color thermal transfer recording using the thermal transfer material of the present invention. ■Thermal transfer material 2 Support 3 Thermal transfer layer 4 First thermal transfer ink layer 4a Heat-melt binder 4b Colorant 5 Second thermal transfer Ink layer 5a...Thermofusible binder 5b...Leuco dye 5C...Color developer 6...Decoloring agent 7...Recording medium 8...Heating elements 9a, 9b...Transfer Representative map of recorded images: Figure 1

Claims (1)

[Scope of Claims] 1. On a support, a layer of a first thermal transferable ink comprising a colorant dispersed in a heat-melting binder, a leuco dye that develops a color tone different from that of the colorant, and the leuco dye. a second thermal transferable ink layer in which a color developer for the dye is dispersed in a thermally fusible binder having a melting point lower than that of the thermally fusible binder; At least one of the second thermal transfer inks contains a decoloring agent that suppresses color development of the leuco dye and has a melting point higher than that of the heat-melting binder of the second thermal transfer ink. Thermal transfer material. 2. The thermal transfer material according to claim 1, wherein the decoloring agent is contained in the second thermal transfer ink.