JPH06155934A - Thermal transfer sheet - Google Patents

Abstract

PURPOSE:To prevent the agglomeration of a dye with the elapse of time and to obtain a sharp high density image without generating background staining by using a specific dye as the dye added to the binder resin of a thermal transfer layer and transferred to an image receiving material by heating. CONSTITUTION:A thermal transfer sheet 1 is fundamentally formed by laminating a thermal transfer layer 3 on the upper surface of a base sheet 2. In this case, the thermal transfer layer 3 is formed from a binder resin containing a dye to be transferred to an image receiving material by heating. As the dye, C.I. solvent blue 63 is used. The binder resin is composed of a polyvinyl butyral resin or a mixture of this resin and a cellulosic resin and a disperse dye is dissolved in this resin. By this constitution, the agglomeration of the dye with the elapse of time and the growth and precipitation of a crystal in the thermal transfer layer are prevented and a sharp high density image is obtained with a relatively low energy without generating background staining.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal transfer sheet, and more particularly to a thermal transfer sheet suitable for obtaining an image on a thermal transfer sheet by performing thermal printing according to image information with a thermal head or a laser.

[0002]

2. Description of the Related Art In order to obtain an image according to image information by a thermal head, a laser or the like, a heat-sensitive color developing paper has been mainly used. In this heat-sensitive color-developing paper, a colorless or light-colored leuco dye and a developer provided on the base paper are brought into contact with each other by heating to obtain a color-developed image. As such a color developer, a phenolic compound, a zinc salicylate derivative, rosin and the like are generally used. However, the above-mentioned thermosensitive color paper has a fatal defect that the obtained color image is erased when stored for a long period of time, and the color printing is limited to two colors and continuous gradation is provided. It was not possible to obtain the color image that it had.

On the other hand, in recent years, heat-sensitive transfer paper, in which a heat-melting wax layer having a pigment dispersed therein is provided on a base paper, has begun to be used. When the heat-sensitive transfer paper and the transfer-receiving paper are superposed and heat printing is performed from the back surface of the heat-sensitive transfer paper, the wax layer containing the pigment is transferred onto the transfer-receiving paper to obtain an image. According to such a printing method, a durable image can be obtained, and a multicolor image can be obtained by printing a plurality of times using a thermal transfer paper containing pigments of three primary colors. It is not possible to obtain an image like a photograph having continuous gradation.

By the way, in recent years, there has been an increasing demand for directly obtaining an image such as a color photograph from an electric signal, and various attempts have been made. One of such attempts is to transfer an image onto a CRT and photograph it with a silver salt film.
When the silver salt film is an instant film, there is a drawback that the running cost is high, and when the silver salt film is a 35 mm film, there is a drawback that it is not immediate because a development process is required after photographing. is there. As another method, an impact ribbon method or an inkjet method has been proposed, but the former has a drawback that the image quality is poor, and the latter requires image processing, so it is not possible to easily obtain an image like a photograph. It has the drawback of being difficult.

In order to solve such a drawback, a thermal transfer sheet provided with a sublimable disperse dye layer having a property of transferring by heating is used in combination with a thermal transfer sheet, and the thermal transfer sheet is controlled while controlling the sublimable disperse dye. A method has been proposed in which a photographic image having gradation is obtained by transferring the image onto a sheet (see Journal of Image Electronics Engineers, Vol. 12, No. 1 (1983)). According to this method, an image having continuous gradations can be obtained from a television signal by a simple process, and the device used at that time is not complicated, so that the method is attracting attention. As one of the conventional techniques close to such a method, there is a dry transfer printing method of polyester fiber. In this dry transfer printing method, a dye such as a sublimable disperse dye is dispersed or dissolved in a synthetic resin solution to prepare a paint, and the paint is applied in a pattern on thin paper or the like and dried to form a heat transfer sheet. Is superposed on the polyester fiber which is a heat transfer sheet, and is heated in close contact to obtain an image by dyeing the disperse dye on the polyester fiber.

However, it is difficult to obtain a high-density color image even if the thermal transfer sheet conventionally used in the dry transfer printing method of polyester fiber is used as it is for heating and printing with a thermal head or the like. The reasons are mainly that the thermal sensitivity of the thermal transfer sheet is not high and that the dye transfer ability of the thermal transfer sheet is low. Among these drawbacks, those caused by the heat transferable sheet have a glass transition temperature of −100 ° C. to 20 ° C. and an island portion composed of a synthetic resin having a polar group and independent from each other.
It has been found that the thermal transfer sheet (Japanese Patent Application No. 58-135627) having a thermal transfer layer formed in a sea-island shape with a sea portion made of a synthetic resin having a glass transition temperature of 0 ° C. or higher is found to be solved. However, the problem caused by the thermal transfer sheet side has not been solved yet. this is,
In the conventional printing method for textiles, for example, 1
Dye transfer / dyeing is achieved by heating for about a minute, while heating by the thermal head is about 400 ° C.
For a few msec. The reason is that it is short and short.

The present inventors have combined with a heat-transferable sheet, particularly the heat-transferable sheet described in the above-mentioned Japanese Patent Application No. 58-135627, in order to obtain a color photographic image by heating and printing with a thermal head or the like. As a result of various studies to obtain a thermal transfer sheet suitable for use as the following, the following facts were found. Conventionally, in a commonly used thermal transfer sheet, the disperse dye is in a state of being dispersed in a binder resin in a granular form, and in order to heat and sublimate the dye molecule in such a state, the interaction in the crystal is required. High energy is required because the dye molecules are given a thermal energy that exceeds the interaction with the binder resin and breaks down to sublimate the dye to be transferred to the heat transfer sheet. When a dye is contained in a high proportion with respect to the binder resin in order to obtain a high-density image, a high-concentration image to some extent can be obtained, but the binding force in the thermal transfer layer of the thermal transfer sheet is weakened, so that the transferred sheet When printed with a thermal head or the like and then peeled off, the phenomenon in which the binder resin and the heat-transferred sheet are taken off easily occurs, and the dye is expensive in price. And than, you stand the OA equipment and home use to the point of view of interest, can be contained in more than necessary dye is disadvantageous economically.

On the other hand, if the dye can be held in the binder resin in the form of a molecular dispersion rather than a granular form, the thermal sensitivity is improved by the amount that there is no interaction in the crystal as in the case of being dispersed in the form of particles. There is expected. However, even if such a state is simply achieved in the binder resin, a practical transfer paper cannot be obtained. That is, the dye molecule of the sublimable dye has a relatively small molecular weight of about 150 to 400 and is easy to move in the binder resin. Therefore, for example, when a binder resin having a low glass transition temperature (Tg) is used, a phenomenon in which the dye aggregates and precipitates over time, and eventually the dye is dispersed in a particle state as described above. Become
Or, since it bleeds to the surface of the thermal transfer layer, the dye adheres to the periphery of the heated portion due to the pressure between the thermal head and the platen (platen) at the time of recording, which causes scumming.
The image quality is significantly deteriorated.

Further, the glass transition temperature (T
Even if g) is high, dye molecules cannot be retained unless the molecular weight of the binder resin is large. Furthermore, even if a dye is molecularly dissolved in a binder resin having a high glass transition temperature (Tg) and a relatively large molecular weight, the dye molecule and the binder resin are required to be stable with time. Affinity of is required. Therefore, the present invention is intended to solve the drawbacks associated with the prior art, and by using a specific thermal transfer sheet containing a disperse dye having a heat transfer property and a thermal transfer sheet in combination, It is intended to achieve such a purpose. (A) To obtain a color image with a dye having a continuous tone like a silver salt photograph directly from an electric signal, (b) To obtain a color image with high heat sensitivity and high density, (c) Long term Even when stored, the thermal transfer sheet does not change with time and retains the above performances (a) and (b).

In order to achieve the above objects, from the viewpoint of the prior art, it is necessary to satisfy the following conditions. (A) When an ink prepared by dissolving a dye molecule and a binder resin is applied onto a base sheet and dried, the dye molecule does not aggregate or precipitate, that is, the affinity between the dye molecule and the binder resin. (B) Furthermore, even if the thermal transfer sheet is stored for a long period of time, the dye molecules do not aggregate or precipitate with time, that is, the affinity between the dye molecules and the binder resin is high. Yes, the glass transition temperature (Tg) of the binder resin is high to some extent, and the molecular weight is also large. (C) The dye molecules can be sufficiently sublimated by heating with a thermal head, that is, the affinity between the dye molecules and the binder resin. Is not excessively high, and the glass transition temperature (Tg) is an appropriate value.

[0011]

The above object can be achieved by the present invention described below. That is, according to the present invention, a thermal transfer layer made of a binder resin containing a dye which is transferred by heating and transferred to a transfer target is laminated on a base sheet, and the dye is C.I. I. A thermal transfer sheet characterized by being Solvent Blue 63.

[0012]

By using a specific dye, agglomeration, crystal growth and precipitation of the dye in the thermal transfer layer with time are prevented, and a high density and clear image can be obtained with relatively low energy without causing scumming. It is formed.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION As shown in FIG. 1, the thermal transfer sheet 1 of the present invention basically comprises a base sheet 2 and a thermal transfer layer 3 provided thereon. Suitable materials for the base sheet 2 are paper such as condenser paper or polyester film, polystyrene film, polysulfone film, polyimide film, polyvinyl alcohol film or cellophane. Of these materials, when importance is attached to price and heat resistance in an untreated state, condenser paper is used. On the other hand, it is preferable to use a polyester film when it is important to have mechanical strength, high rupture strength during handling during preparation of a thermal transfer sheet and running in a thermal printer, and smooth surface. .
The thickness of the base sheet 2 is 3 to 50 μm, preferably 3 to 1
It is 5 μm.

The thermal transfer layer 3 is composed of a binder resin containing a dye which is transferred by heating and transferred to a transfer target. The thickness of the thermal transfer layer 3 is 0.5 to 5.0 μm,
It is preferably about 0.5 to 2.0 μm. In the present invention, the dye contained in the thermal transfer layer is C.I. I. Use Solvent Blue 63. This dye can be used in the present invention, for example, obtained from Nippon Kayaku Co., Ltd. under the trade name of Kayaset Blue 714. Further, in the present invention, the above C. I. Solvent Blue 63 may be used alone or in combination with another dye for the purpose of toning. The dye that may be used in combination is more preferably a disperse dye and has a small molecular weight of about 150 to 400, and the thermal sublimation temperature, hue, weather resistance, and solubility in ink and binder resin are taken into consideration. The following are specifically exemplified.

C. I. Disperse Yellow 42 (manufactured by Mitsui Toatsu, Miketone Polyester Yellow-YL) C.I. I. Disperse Yellow 5 (Mikei Toatsu, Miketone Polyester Yellow-5G) C.I. I. Solvent Yellow 77 (Nippon Kayaku, Kayaset Yellow G) C.I. I. Solvent Yellow 125 (S) (Nippon Kayaku, Kayaset Yellow A-N), C.I. I. Disperse Yellow 14-1 (manufactured by Mitsubishi Kasei,
PTY-52) C.I. I. Disperse Yellow 3 (Made by Mitsubishi Kasei, PTY
-56) C.I. I. Disperse Red 111 (Mitsui Toatsu, Miketone Polyester Red-BSF) C.I. I. Disperse Red 228 (S) (Mitsui Toatsu, Miketone Polyester Red-T3B) C.I. I. Disperse Red 135 (Nippon Kayaku, Kayaset Red B) C.I. I. Disperse Red 4 (Nippon Kayaku, Kayaset Red 126) C.I. I. Disperse Red 50 (Mitsubishi Chemical, PTR
-54) C.I. I. Disperse Red 60 (Made by Mitsubishi Kasei, PTR
−63) C.I. I. Disperse Blue 56 (Mitsui Toatsu, Miketone Polyester Blue-FBL)

C. I. Disperse Blue 106 (Mitsui Toatsu, Discharge Blue R) C.I. I. Solvent Blue 33 (Mitsui Toatsu, Mitsui P)
S blue 3R) C.I. I. Disperse Blue 241 (Mitsubishi Kasei, PT
B-67) C.I. I. Solvent Blue 90 (Mitsubishi Chemical Co., PTB-
77) C.I. I. Solvent Blue 112 (Nippon Kayaku, Kayaset Blue 906) C.I. I. Solvent Blue 114 (S) (manufactured by Nippon Kayaku,
Kayaset Blue 141) C.I. I. Disperse Violet 26 (Made by Bayer,
Macrolex Red Violet R) C.I. I. Solvent Red 19 (made by Bayer, Seres Red 7B) C.I. I. Disperse Red 60 (MS Red G, manufactured by Mitsui Toatsu Co., Ltd.) The ratio of the dye contained in the thermal transfer layer depends on the sublimation temperature of the dye and the covering power (color rendering property) in a colored state, but usually 5 ~ 70%, preferably 10-60
%.

Polyvinyl butyral resin is preferable as the main part of the binder resin constituting the thermal transfer layer 3, and more preferable polyvinyl butyral resin has a molecular weight of 60,000 or more in the sense of producing a binding force as a binder (at the time of coating). In order to prevent dye aggregation, crystal growth, and precipitation in the thermal transfer layer 3, the glass transition temperature (Tg) is 60 ° C. or more, The temperature is preferably 70 ° C. or higher (preferably 110 ° C. or lower from the viewpoint of facilitating sublimation of the dye), and in order to improve the affinity with the dye due to hydrogen bonding or the like, the weight% of the vinyl alcohol moiety is Is 10 to 40%, preferably 1 in the polyvinyl butyral resin.
5 to 30%.

In order to improve the drying property when the thermal transfer layer is formed by coating, the binder resin may be replaced with a cellulose resin up to 10% of the weight of the binder resin. Examples of such a preferable cellulose resin include ethyl cellulose, hydroxyethyl cellulose, ethyl hydroxycellulose, ethyl hydroxyethyl cellulose, hydroxypropyl cellulose, nitrocellulose and the like.

In order to provide the thermal transfer layer 3 on the base sheet 2, a dye and a binder resin are dissolved together with a solvent to prepare an ink composition for forming a thermal transfer layer, which can be applied and dried by an appropriate printing method or application method. Good. If desired, any additive may be added to the thermal transfer layer forming ink composition. The basic constitution of the thermal transfer sheet of the present invention is as described above, but when the surface of the base sheet 2 is directly heated by a contact type heating means such as a thermal head, as shown in FIG. By providing the lubricating layer 4 containing a lubricant such as wax or a release agent on the side of the base sheet 2 where the thermal transfer layer is not provided, fusion between the heating means such as a thermal head and the base sheet is prevented. You can improve the slip.

The shape of the thermal transfer sheet of the present invention may be in the form of a single sheet cut into the required size, or may be continuous or wound, and is a narrow tape shape. May be. As a method for providing the thermal transfer layer 3 on the base sheet 2, the surface of the base sheet 2 may be entirely coated with the ink composition for the thermal transfer layer containing the same coloring material, but it may be different depending on the case. A plurality of thermal transfer layer ink compositions each containing a color material may be formed on different areas of the surface of the base sheet 2. For example, as shown in FIG. 3, a black thermal transfer layer 5 and a red thermal transfer layer 6 may be manufactured by stacking the black thermal transfer layer 5 and the red thermal transfer layer 6 in parallel on the base sheet 2, or as shown in FIG. As shown, the thermal transfer sheet may be manufactured by repeatedly providing the yellow thermal transfer layer 7, the red thermal transfer layer 8, the blue thermal transfer layer 9, and the black thermal transfer layer 10 on the base sheet 2.

When a plurality of thermal transfer layers having different hues are provided on the thermal transfer sheet as described above, there is an advantage that a multicolor image can be obtained by simply using one thermal transfer sheet. The thermal transfer sheet may be provided with a registration mark or the like for forming perforations or detecting the positions of areas having different hues, so that it can be conveniently used. The thermal transfer sheet prepared as described above includes the thermal transfer sheet, for example, the thermal transfer layer 3 of the thermal transfer sheet 1 as shown in FIG. 5, and the base sheet 12 of the thermal transfer sheet.
The dyes in the thermal transfer layer are transferred to the image-receiving layer by applying the heat energy corresponding to the image information to the interface between the thermal transfer layer and the image-receiving layer so as to face each other so that the upper image-receiving layer 13 is in contact.

In addition to the thermal head 14, a known source such as a laser beam, an infrared flash, or a heating pen can be used as a heat source for providing heat energy. The thermal energy may be applied from the thermal transfer sheet side, from the thermal transfer sheet side or from both sides, but from the viewpoint of effective utilization of thermal energy, the thermal transfer sheet side is preferred. However, in order to express the gradation of light and shade of the image, it is easy to control the heat energy to be applied or the color material is promoted to diffuse on the heat-transferred sheet to express the continuous gradation of the image. From the viewpoint of ensuring the reliability, it is preferable to apply heat energy from the heat transfer target sheet side. Further, by applying the heat energy from both sides, both advantages described above can be enjoyed at the same time.

When a thermal head is used as a heat source for applying heat energy, the applied heat energy can be changed continuously or in multiple steps by modulating the voltage or pulse width applied to the thermal head. When laser light is used as a heat source for giving heat energy, the heat energy to be given can be changed by changing the light amount of the laser light or the irradiation area. If a dot generator with a built-in acousto-optic element is used, it is possible to give heat energy according to the size of the halftone dot. When using a laser beam, it is advisable to bring the thermal transfer sheet and the thermal transfer sheet into close contact with each other.
Further, the surface irradiated with the laser light may be colored black, for example, in order to improve the absorption of the laser light.

If a non-sublimable substance that absorbs laser light and converts it into heat is added to the thermal transfer layer 3, the heat transfer to the dye is performed more efficiently and the resolution is increased. When using an infrared flash lamp as a heat source for providing heat energy, it may be performed in the same manner as when using a laser beam, or a pattern in which the shade of an image such as black is continuously expressed, or a halftone dot pattern is used. You may perform it via the pattern of. Alternatively, in connection with the latter, the colored layer of one surface such as black may be combined with a negative pattern of any one of the above patterns. When heat energy is applied to the interface between the thermal transfer layer and the image receiving layer as described above,
The dye in the thermal transfer layer thermally transfers to the image receiving layer 13 in an amount according to the applied thermal energy and is received to form an image.

The image thus obtained is a monochromatic image, but a thermal transfer sheet of a plurality of different colors, such as yellow,
It is also possible to sequentially replace the thermal transfer sheets of red, indigo, and black, if necessary, to perform thermal transfer, and obtain an image like a color photograph, which is a combination of the colors. Further, when forming an image such as a color photograph, instead of sequentially replacing the thermal transfer sheets of the respective colors to perform thermal transfer,
As shown in FIG. 4, a single thermal transfer sheet is prepared by separately coating areas of each color separately. For example, first, a yellow color-separated image is thermally transferred using the yellow areas of the thermal transfer sheet,
Next, the red color-separated image is thermally transferred using the red area of the same thermal transfer sheet, and thereafter, the same operation is sequentially repeated for indigo and black, so that yellow, red, indigo and, if necessary, By adopting the method of thermally transferring the black color separation images, it is possible to form a color image like a color photograph without replacing the thermal transfer sheet. The quality of the obtained image can be improved by appropriately adjusting the size of the heat source used to apply the heat energy, the adhesion between the heat transfer sheet and the heat transfer target sheet, and the heat energy.

The thermal transfer sheet of the present invention can be combined with a thermal transfer sheet for printing using various thermal printing printers, facsimiles, photographic prints by a magnetic recording system, or prints from a television screen. Available. For example, one screen of the received television is stored in a storage medium such as a magnetic tape or a magnetic disk as a signal of each color separation pattern of yellow, red, indigo, and black if necessary, and each stored screen is stored. A signal of a color separation pattern is output, and heat energy corresponding to the output signal is applied to the superposed body of the thermal transfer sheet and the thermal transfer sheet by the heat source such as a thermal head,
By successively performing thermal printing for each color, the screen of the television can be reproduced as a sheet-like print.

When a combination of the heat-transferable sheet and the heat-transferable sheet of the present invention is used for printing out the screen of a television, the heat-transferable sheet is usually a white image-receiving layer alone or a colorless transparent film. It is convenient to obtain a reflection image when an image receiving layer backed by a base material such as paper or a white image receiving layer backed by a base material such as paper is used. In addition to the above, the thermal transfer sheet of the present invention is
It is also possible to use a graphic pattern or the like as an original image by combining with a character, figure, symbol, color or the like formed on the CRT screen by operating a computer. When the original image is a fixed image such as a painting, photograph, or printed matter, or a person,
When the object is an actual object such as a still life or a landscape, the same operation can be performed by using an appropriate means such as a video camera as an intermediary. When extracting the signals of each color separation pattern from the original image, an electronic plate making machine (color scanner) used for photolithography of printing may be used.

[0028]

EXAMPLES The present invention will be described more specifically with reference to Examples and Comparative Examples. Example 1 As a base sheet, a thickness of 9 μ having corona treatment on one side
m PET film (S-PET manufactured by Toyobo Co., Ltd.) was coated with a thermal transfer layer-forming ink composition having the following composition by wire bar coating so that the coating weight when dried was 1.0 g / m ² and dried. Then, after dropping one drop of silicone oil (X-414003A made by Shin-Etsu Silicone) on the back surface, spread it on the entire surface and apply back surface treatment,
The heat transfer sheet of the present invention was used.

Ink composition for thermal transfer layer Disperse dye (Nippon Kayaku, Kayaset Blue 714) 4 parts by weight Polyvinyl butyral resin (Sekisui Chemical, S-LEC BX-1) Ethyl hydroxycellulose 0.3 parts by weight Toluene 40 Parts by weight Methyl ethyl ketone 40 parts by weight Isobutanol 10 parts by weight Here, the polyvinyl butyral resin (BX-1) has a molecular weight of about 100,000, a Tg of 83 ° C., and a weight% of a vinyl alcohol portion of about 20% by weight. The resulting thermal transfer layer was transparent, and no particles were observed even when observed with a microscope (magnification: 400). Next, as a base sheet, a thickness of 15
0 μm thick synthetic paper (Oji Yuka, YUPO-FPG 1
50) is prepared, and an ink composition for an image receiving layer having the following composition is applied by a wire bar coating method to give a coating weight of 5 when dried.
After coating so as to be g / m ² , it was dried to obtain a heat transfer sheet. Drying was carried out for 1 hour in an oven at a temperature of 100 ° C. after temporary drying with a dryer to sufficiently volatilize the solvent.

Ink composition for image receiving layer Polyester resin (Voylon 103 manufactured by Toyobo) 8 parts by weight EVA polymer plasticizer (Elvalloy 741 manufactured by Mitsui Polychemical) 2 parts by weight Amino-modified silicone oil (KF- manufactured by Shin-Etsu Silicone Co., Ltd.) 393) 0.125 parts by weight Epoxy-modified silicone oil (X-22-343 manufactured by Shin-Etsu Silicone) 0.125 parts by weight Toluene 70 parts by weight Methyl ethyl ketone 10 parts by weight Cyclohexanone 20 parts by weight

The thermal transfer sheet and the thermal transfer sheet obtained as described above are stacked so that the thermal transfer layer and the image receiving layer are in contact with each other, and the thermal head outputs from the base sheet side of the thermal transfer sheet; 1 W / 1 dot, pulse width; 0.3 to 4.5 msec, dot density; 3 dots /
As a result of recording under the condition of mm, pulse width is 4.5 ms
ec. The reflection density of the high-density color-developed portion is 1.65 and the pulse width is 0.3 msec. The reflection density of the low-density color-developed part of 0.
16 and recording with gradation according to the applied energy was obtained (measuring machine; Macbeth densitometer RD-918).
Also, when printing with a thermal head and peeling off the heat transfer sheet and the heat transfer target sheet, no transfer of the resin of the heat transfer layer onto the image receiving layer was observed, and scumming of the non-heated portion also occurred. There wasn't. Further, even when the same thermal transfer sheet was left in an oven at a temperature of 60 ° C. for 30 days in a wound state, no apparent change or deterioration of recording performance was observed, showing sufficient practicality.

Example 2 The thermal transfer of the present invention was carried out in the same manner as in Example 1 except that the polyvinyl butyral resin in the ink composition for the thermal transfer layer was changed from BX-1 to Denka Butyral 5000-A (manufactured by Denki Kagaku). The sheet was manufactured. Denka Butyral 5000
-A has a molecular weight of about 130,000, a Tg of about 78 ° C., and a weight% of the vinyl alcohol portion is about 16% by weight. When the obtained thermal transfer sheet was combined with the same thermal transfer sheet as used in Example 1 and recorded under the same conditions as in Example 1, the pulse width was 4.5 msec. The reflection density of the high-density color-developed portion is 1.70 and the pulse width is 0.3 msec. The reflection density of the low-density color-developed portion was 0.17. In addition, neither the background stain of the non-heated portion nor the transfer of the resin which occurs when the both sheets are peeled off occurred. Furthermore, when a heating acceleration test was performed under the same conditions as in Example 1, no change was observed.

Example 3 The thermal transfer of the present invention was carried out in the same manner as in Example 1 except that the polyvinyl butyral resin in the ink composition for the thermal transfer layer was changed from BX-1 to Denka Butyral 6000-C (manufactured by Denki Kagaku). The sheet was manufactured. Denka Butyral 6000
-C has a molecular weight of about 155,000, a Tg of about 90 ° C., and a weight% of the vinyl alcohol portion of about 16% by weight. When the obtained thermal transfer sheet was combined with the same thermal transfer sheet as used in Example 1 and recorded under the same conditions as in Example 1, the pulse width was 4.5 msec. The reflection density of the high-density color-developed portion is 1.60 and the pulse width is 0.3 msec.
The reflection density of the low-density color-developed portion was 0.10. or,
The results of other aging tests were also good.

Example 4 The thermal transfer of the present invention was carried out in the same manner as in Example 1 except that the polyvinyl butyral resin in the ink composition for the thermal transfer layer was changed from BX-1 to Denka Butyral 4000-1 (manufactured by Denki Kagaku). The sheet was manufactured. Denka Butyral 4000
-1 has a molecular weight of about 60,000, a Tg of about 80 ° C., and the weight% of the vinyl alcohol portion is about 20% by weight. When the obtained thermal transfer sheet was combined with the same thermal transfer sheet as used in Example 1 and recorded under the same conditions as in Example 1, the pulse width was 4.5 msec. The reflection density of the high-density color-developed portion is 1.90 and the pulse width is 0.3 msec. The reflection density of the low-density color-developed portion of was 7. In addition, the results of other aging tests were also good.

Example 5 As in Example 1, except that the following ink composition was used for the thermal transfer layer, and the coating weight when dried was 1.0 g / m ^2.
Was applied onto a base sheet to give a thermal transfer sheet of the present invention. Ink composition for thermal transfer layer Disperse dye (Nippon Kayaku, Kayaset Blue 714) 4 parts by weight Polyvinyl butyral resin (Sekisui Chemical, S-LEC BX-1) 4 parts by weight Ethylcellulose (Hercules, EC N-14) 0.3 parts by weight Toluene 40 parts by weight Methyl ethyl ketone 40 parts by weight Isobutanol 10 parts by weight Using the obtained thermal transfer sheet, recording was performed in the same manner as in Example 1, and the same recording performance as in Example 1 was obtained. Also, there was no problem in stability over time.

Example 6 The same results as in Example 5 were obtained in the same manner as in Example 5, except that the same amount of hydroxyethyl cellulose, hydroxypropyl cellulose or nitrocellulose was used instead of the cellulose resin in Example 5. It was

[0034]

As described above, according to the present invention, the use of the specific dye prevents the dye from aggregating, growing and precipitating with time in the thermal transfer layer, and does not cause scumming and has a relatively low level. Energy creates a high density and sharp image.

[0035]

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a thermal transfer sheet of the present invention.

FIG. 2 is a sectional view of the thermal transfer sheet of the present invention.

FIG. 3 is a perspective view of a thermal transfer sheet of the present invention.

FIG. 4 is a perspective view of a thermal transfer sheet of the present invention.

FIG. 5 is an explanatory diagram illustrating a method for transferring using the thermal transfer sheet of the present invention.

[Explanation of symbols]

 1: Thermal Transfer Sheet 2: Base Sheet 3: Thermal Transfer Layer 11: Thermal Transfer Sheet 12: Base Sheet 13: Image Receiving Layer 14: Thermal Head 15: Plantain Roll

Claims (3)

[Claims] 1. A thermal transfer layer made of a binder resin containing a dye that is transferred by heating and transferred to a transfer target is laminated on a base sheet, and the dye is C.I. I. A thermal transfer sheet characterized by being Solvent Blue 63. 2. The thermal transfer sheet according to claim 1, wherein the binder resin is a polyvinyl butyral resin or a mixture of a polyvinyl butyral resin and a rocellulose resin. 3. The thermal transfer sheet according to claim 1, wherein the disperse dye is dissolved in a binder resin.