JPH06155929A - Thermal transfer sheet - Google Patents

Abstract

PURPOSE:To achieve high density thermal transfer by composing the binder component of the dye layer to be formed on a base material sheet from a mixture of specific resins and using at least one kind of dyes respectively represented by specific formulae or a mixture of them as the dye contained in the dye layer. CONSTITUTION:A thermal transfer sheet 1 is constituted by farming a dye layer 2 on a base material sheet 2. The binder component of the dye layer 3 is composed of a mixture of at least one kind of a resin selected from a group consisting of a polycarbonate resin, a vinyl chloride/vinyl acetate copolymer, an ethylene/acrylonitrile copolymer, a polyvinyl acetal resin, a phenoxy resin and an ethyl cellulose resin and an ethyl/hydroxy ethyl cellulose resin.

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 specifically, when the thermal transfer sheet itself is stored and heat-printed according to image information by a thermal head or a laser, a high-density thermal transfer with low energy is performed. It is an object of the present invention to provide a thermal transfer sheet which is capable of achieving excellent sharpness and light resistance.

[0002]

2. Description of the Related Art Conventionally, a heat-sensitive coloring paper has been mainly used for forming an image according to image information by using a thermal printing means such as a thermal head or a laser. 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 form a color image having it.

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 heat-transfer image-receiving sheet are superposed and heat printing is performed from the back surface of the binder resin, the wax layer containing the pigment is transferred onto the heat-transfer image-receiving sheet 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 binder resin containing a pigment of three primary colors, but it is essentially continuous. It is not possible to form a photo-like image having various gradations. 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 a method of displaying an image on a CRT and photographing it with a silver salt film, but when the silver salt film is an instant film, there is a drawback that running costs increase, and However, 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.

As another method, an impact ribbon method or an ink jet method has been proposed, but the former has a drawback that the image quality is poor, and the latter requires image processing, so that it can be easily performed like a photograph. There is a drawback that it is difficult to form an image. In order to solve such a defect, a thermal transfer sheet provided with a sublimable dye layer having a property of being transferred by heating is used in combination with a thermal transfer image receiving sheet, and the dye on the thermal transfer image receiving sheet is controlled while controlling the sublimable dye. Has been proposed (see Journal of Image Electronics Engineers, Volume 12 No. 1 (1983)). According to the above method, an image having continuous gradations can be obtained from a television signal by a simple process, and a 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. This dry transfer printing method is an ink in which a dye such as a sublimable disperse dye is dispersed or dissolved in a synthetic resin. Then, this ink is applied in a pattern on thin paper and dried to form a thermal transfer sheet. This thermal transfer sheet is superposed on a polyester cloth which is a thermal transfer image-receiving sheet, and heated in close contact to dye a dye on the polyester cloth to form an image. Is a method of forming.

[0005]

[Problems to be Solved by the Invention] However, it is difficult to form a high density color image even if the thermal transfer sheet conventionally used in the dry transfer printing method of polyester cloth is used as it is for printing by heating with a thermal head or the like. Is. The main reasons are that the thermal sensitivity of the thermal transfer sheet is not high and the dye transfer ability of the thermal transfer image-receiving sheet is low. Among these defects, those caused by the thermal transfer image-receiving sheet side are −100 ° C. to 2 ° C.
Dye-receiving layer having a glass transition temperature of 0 ° C. and islands made of a synthetic resin having a polar group, which are independent of each other, and sea portions made of a synthetic resin having a glass transition temperature of 40 ° C. or more, formed in a sea-island shape. It has been found that the thermal transfer image-receiving sheet (Japanese Patent Application No. 58-135627) has a problem, but the problem attributable to the thermal transfer sheet side has not been solved yet. This is because, in the conventional textile printing method, for example, the dye transfer and dyeing are achieved by heating at 200 ° C. for about 1 minute, while the heating by the thermal head is performed at about 400 ° C. for several msec. ． The reason is that it is short and short.

The present inventors use it in combination with a thermal transfer image-receiving sheet, in particular, the thermal transfer image-receiving sheet described in Japanese Patent Application No. 58-135627, which is mentioned above, in order to form 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 the following, the following facts were found. That is, in a generally used thermal transfer sheet, the dye is in a state of being dispersed in the 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. Defeat,
Furthermore, since heat energy exceeding the interaction with the binder resin must be given to the dye molecules to sublimate and dye them to the thermal transfer image-receiving sheet, high energy is required and in order to obtain a high-density color image. When a high proportion of the dye is contained in the binder resin, a high-concentration image can be obtained to some extent, but the adhesive force between the dye layer of the thermal transfer sheet and the base sheet is weakened. If the thermal transfer sheet is peeled off after the thermal transfer image receiving sheet is overlaid and printed with a thermal head or the like, not only the dye but also the entire dye layer is easily peeled off by the thermal transfer image receiving sheet, and the dye is expensive in price. From the standpoint of OA equipment and home use, it is economically disadvantageous to add more dye than necessary.

On the other hand, if the dye can be held in the binder resin in the form of a molecular dispersion instead of a granular form, the thermal sensitivity is improved because 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 thermal transfer sheet cannot be obtained. That is, the thermally sublimable dye molecule has a relatively small molecular weight of about 150 to 550 and easily moves in the binder resin forming the dye layer. Therefore, for example, when a binder resin having a low glass transition temperature (Tg) is used, development occurs in which the dye agglomerates and projects in the dye layer over time, and as a result, the dye is dispersed in the form of particles as described above. Or the dye bleeds out on the surface of the dye layer, so that the pressure between the thermal head and the platen (platen) at the time of recording causes the dye to adhere around the heated area. This causes scumming and significantly deteriorates the image quality. Even if the glass transition temperature (Tg) of the binder resin is high, the dye molecules cannot be retained unless the molecular weight of the binder resin is large to some extent. 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. In view of these points, various types of thermal transfer sheets have been conventionally proposed for the purpose of improving image quality. For example, as described in JP-A-63-151484, by using a specific polyvinyl acetoacetal resin as a binder resin component in the dye layer ink, it is possible to improve the print quality and the stability with time. It is known that you can do it.

However, these conventional thermal transfer sheets are not always sufficiently satisfactory in terms of sensitivity. In addition, ethyl hydroxyethyl cellulose and ethyl cellulose are known as binder resins having excellent sensitivity, but these binder resins have a drawback in that they are inferior in storage stability in terms of dye aggregation / precipitation prevention properties. Generally, as a condition required for a thermal transfer sheet, the storability of the thermal transfer sheet itself is important as well as various characteristics relating to image quality such as printing sensitivity and resolution. However, printing sensitivity and storability tend to cancel each other out, and it is difficult to improve both of these characteristics. Therefore, an object of the present invention is to solve the above-mentioned problems of the prior art,
When the thermal transfer sheet itself is storable and heat printing is performed according to the image information with a thermal head or laser,
It is an object of the present invention to provide a thermal transfer sheet which is capable of high-density thermal transfer with low energy and is excellent in sharpness and light resistance.

[0009]

The above object can be achieved by the present invention described below. That is, the present invention comprises a base sheet and a dye layer formed on the base sheet, and the binder component of the dye layer is a polycarbonate resin, a vinyl chloride / vinyl acetate copolymer, or a styrene / acrylonitrile copolymer. , A polyvinyl acetoacetal resin, a phenoxy resin, and an ethyl cellulose resin, and a dye contained in the dye layer, which is composed of a mixture of at least one resin selected from the group consisting of ethyl hydroxyethyl cellulose resin and the above formulas 1 to 4 Or at least one of the dyes represented by the above formulas 1 to 4 and at least one of the dyes represented by the above formulas A to X.
A thermal transfer sheet, which is a mixture with a seed, and a substrate sheet and a dye layer formed on the substrate sheet, wherein the binder component of the dye layer contains at least isocyanate-reactive cellulose, Containing at least one resin selected from the group consisting of the cellulose and an isocyanate-reactive acetal resin, an isocyanate-reactive vinyl resin, an isocyanate-reactive acrylic resin, an isocyanate-reactive phenoxy resin and an isocyanate-reactive styrene resin, and a polyisocyanate compound. The dye contained in the dye layer is at least one of the dyes represented by the formulas 1 to 4, or at least 1 of the dyes represented by the formulas 1 to 4. Species and at least one of the dyes of formulas A-X above
It is a thermal transfer sheet characterized by being a mixture with seeds.

[0010]

[Function] By adopting a specific binder resin as a binder component constituting the dye layer, the thermal transfer sheet itself has excellent storability, and by mixing and using a specific dye, heat energy of an extremely short time can be obtained. Even when applied, it is possible to provide a thermal transfer sheet which gives a full-color image excellent in color density, sharpness and light resistance.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail below with reference to the preferred embodiments shown in the drawings. The thermal transfer sheet 1 according to the present invention, as shown in FIG.
It is configured by providing the dye layer 3 on the top. As the base sheet 2, condenser paper, polyester film, polystyrene film, polysulfone film, polyimide film, polyvinyl alcohol film, cellophane, etc. aramid film, polyetherimide film,
Paper or film such as polyetheretherketone film or polyparbanic acid film is used, and the thickness thereof is 1.5 to 50 μm, preferably 2 to 9 μm.
Condenser paper is used when price and heat resistance in the untreated state are required among these papers and films, while it has mechanical strength and can be used when handling thermal transfer sheets or in thermal printers. A polyester film is preferably used when it is important that the film does not break when it is run and that the surface is smooth.

The dye layer 3 is mainly composed of a specific binder component and a specific dye component. The binder used in the present invention is a polycarbonate resin in the first present invention,
It is a mixture of ethyl hydroxyethyl cellulose resin and at least one resin selected from the group consisting of vinyl chloride / vinyl acetate copolymer, styrene acrylonitrile copolymer, polyvinyl acetoacetal resin, phenoxy resin and ethyl cellulose resin. In the mixture, at least one resin selected from the group consisting of polycarbonate resin, vinyl chloride / vinyl acetate copolymer, styrene acrylonitrile copolymer, polyvinyl acetoacetal resin, phenoxy resin and ethyl cellulose resin, and ethyl hydroxyethyl cellulose resin. The weight ratio of the amount used is 100 parts by weight of the former, and the latter is 25 to 100 parts by weight.
A range of 400 parts by weight is preferred. If the amount used is less than the above range, the printing sensitivity is insufficient, and thus a large amount of heat energy is required to obtain the required color density. In addition, it is not preferable because it is difficult to obtain an appropriate viscosity for providing the dye layer on the substrate sheet. On the other hand, if the amount exceeds the above range, aggregation and precipitation of the dye are likely to occur, and the storage stability is deteriorated, which is not preferable.

The binder resin used in the second invention contains at least isocyanate-reactive cellulose, and the cellulose and isocyanate-reactive acetal resin, isocyanate-reactive vinyl resin, isocyanate-reactive acrylic resin, isocyanate-reactive phenoxy resin. And a composition containing at least one resin selected from the group consisting of an isocyanate-reactive styrene resin and a polyisocyanate compound, and finally cured. In the above, the weight ratio of the amount of at least isocyanate-reactive cellulose and the amount of at least one resin selected from the group consisting of acetal resin, vinyl resin, acrylic resin, phenoxy resin and styrene resin that is isocyanate-reactive with the cellulose is used. Is preferably in the range of 25 to 400 parts by weight per 100 parts by weight of the former. If the amount of the latter used is less than the above range,
It is not preferable because the dye easily aggregates or precipitates and the storage stability is deteriorated. On the other hand, if the amount exceeds the above range, the printing sensitivity is insufficient, so that a larger heat energy is required to obtain the required color density, and it is difficult to form a high density color image in a short time, which is preferable. Absent.

The amount of polyisocyanate groups in the polyisocyanate compound used is 0.01 to 4 times the amount of active hydrogen in the resin mixture, more preferably 0.05.
To 3 times the range. If the amount used is less than the above range, separation / precipitation of the mixed resin or dye may occur, stable performance may not be obtained, and it may be difficult to obtain the viscosity required for printing / coating. Is not preferable. On the other hand, if the amount exceeds the above range, the gelation of the resin or the solubility in a solvent is deteriorated, which makes it difficult to mix with a dye and to print / apply, which is not preferable.

As the polyisocyanate used in the present invention, various polyisocyanates widely used in conventional polyurethane resins, polyurethane paints, polyurethane adhesives, etc., such as 2,4-tolylene diisocyanate (2,4) -TDI), 2,5-tolylene diisocyanate (2,5-TDI), 4,4'-diphenylmethane diisocyanate (MDI), hexamethylene diisocyanate (HMDI), isophorone diisocyanate, triphenylmethane triisocyanate, tris (isocyanate phenyl) ) Thiophosphate, lysine ester triisocyanate, 1,8-diisocyanate-4-isocyanate methyloctane, 1,6,11
-Undecane triisocyanate, 1,3,6-hexamethylene triisocyanate, bicycloheptane triisocyanate, biuret-bonded HMDI, isocyanate-bonded HMDI, trimethylolpropane-TDI
Examples thereof include a 3 mol adduct or a mixture thereof. In the present invention, in addition to the binder resin as described above, other binder resins can be used in an amount of 50% by weight or less based on the whole, as long as the object of the present invention is not impaired.

The dyes used in the present invention are as described above, and they may be used alone or as a mixture. In the present invention, the use ratio of the dyes of formulas 1 to 4 and formulas A to X is preferably in the range of 0 to 300 parts by weight per 100 parts by weight of the former. When the amount exceeds the above range, it is expected that the sensitivity, the density, and the storage stability of the thermal transfer sheet itself can be improved.
It is not preferable because the light resistance of the image is lowered. Specific examples of preferred dyes used in the present invention are shown below by substituents.

[0017]

Table 1 Dyes of formula 1

[0018]

Table 2 Dyes of formula 2

[0019]

Table 3 Dyes of formula 3

[0020]

Table 4 Dyes of formula 4

The proportion of the dye contained in the dye layer depends on the sublimation (melting) temperature of the dye and the covering power (color rendering) in the color-developed state, but the weight ratio of the dye to the binder resin component is The (dye / binder resin ratio) is preferably 0.3 or more, more preferably 0.3 to 3.0.
And most preferably 0.55 to 2.5. If the dye / binder resin ratio is less than 0.3, the image quality such as print density and heat sensitivity is not preferable, while 3.0
If it exceeds, the adhesiveness to the film and the preservability tend to be deteriorated. To provide the dye layer 3 on the base sheet 2, a dye and a binder resin are dissolved with a suitable solvent to form a dye layer ink, which is applied on the base sheet 2 by an appropriate printing method or coating method. It may be dried.
Further, the dye is preferably in a substantially dissolved state in the binder resin. If desired, any additive may be added to the dye layer ink.

The basic constitution of the thermal transfer sheet of the present invention is as described above, but when the surface of the base sheet is directly heated by a contact type heating means such as a thermal head, it is shown in FIG. Similarly, by providing the lubricant layer 4 containing a lubricant such as wax or a release agent on the side of the base sheet 2 where the dye layer 3 is not provided, the heating means such as a thermal head and the base sheet can be combined. It is possible to prevent fusion and improve slipperiness. The thermal transfer sheet of the present invention may be in the form of a single sheet cut into a required size, may be in the form of a continuous sheet or in the form of a roll, and may be in the form of a tape having a narrow width. When the dye layer 3 is provided on the base material sheet 2, the dye layer ink containing the same dye may be applied to the entire surface of the base material sheet 2, but in some cases, different dyes may be used. You may form the several dye layer ink containing in each area | region where the surface of the base material sheet 2 differs. For example, a thermal transfer sheet in which a black dye layer 5 and a red dye layer 6 are laminated in parallel on a base material sheet 2 as shown in FIG. 3, or a yellow dye layer 7 as shown in FIG. It may be a thermal transfer sheet in which the red dye layer 8, the blue dye layer, and the black dye layer 10 are repeatedly provided on the base material sheet 2.

By using such a thermal transfer sheet provided with a plurality of dye layers having different hues, there is an advantage that a multicolor image can be obtained by one thermal transfer sheet. Incidentally, the thermal transfer sheet can be conveniently used by forming a perforation or providing a detection mark or the like for detecting the position of an area having a different hue. The thermal transfer sheet and the optional thermal transfer image-receiving sheet of the present invention configured as described above are prepared, for example, as shown in FIG. 5, the dye layer 3 of the thermal transfer sheet 1 and the dye-receiving layer 13 on the base sheet 12 of the thermal transfer image-receiving sheet. By applying heat energy corresponding to image information to the interface between the dye layer 3 and the dye receiving layer 13 by a heat applying means such as a thermal head 14 so that the dye in the dye layer 3 and the dye receiving layer 13 face each other. 1
By shifting to No. 3, a desired image can be formed in the dye receiving layer 13.

As the heat source for giving heat energy, in addition to the thermal head 14, laser light, infrared flash,
A known one such as a hot pen can be used. The thermal energy may be applied from the thermal transfer sheet side, from the thermal transfer image receiving sheet side or from both sides, but from the viewpoint of effective utilization of thermal energy, the thermal transfer sheet side is preferred. . However, when the heat energy is applied from the thermal transfer image receiving sheet side, the applied heat energy is controlled to express the gradation of the light and shade of the image,
Alternatively, it is preferable in the sense that the dye is promoted to diffuse on the thermal transfer image-receiving sheet to more reliably represent the continuous tone of the image, and in the method of applying heat energy from both sides, the advantages of the both methods are simultaneously obtained. You can enjoy it.
When the thermal head 14 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 quantity of the laser light or the irradiation area. Further, 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 laser light,
The thermal transfer sheet and the thermal transfer image-receiving sheet are preferably brought into close contact with each other, and the surface irradiated with the laser light is preferably colored black, for example, in order to improve absorption of the laser light. Alternatively, if a substance that absorbs non-sublimable laser light and converts it into heat is added to the dye layer 3, the heat transfer to the dye is performed more efficiently and the resolution of the image is increased. When an infrared flash lamp is used as a heat source for giving heat energy, it may be carried out in the same manner as in the case of using a laser beam, or through a pattern or a halftone dot pattern which continuously expresses the shade of an image such as black. It may be carried out, or may be carried out by combining a black colored layer on one surface with a negative pattern corresponding to the negative of the above pattern.

When heat energy is applied to the interface between the dye layer and the dye receiving layer as described above, the dye in the dye layer is transferred to and received by the dye receiving layer 13 in an amount corresponding to the applied heat energy. To form a desired image. By the thermal transfer recording as described above, the dye corresponding to the thermal energy is thermally transferred to the dye receiving layer to record an image of one color. However, the above method can be performed by replacing the thermal transfer sheet, for example,
It is also possible to form a photographic color image composed of each color by sequentially replacing the yellow, red, indigo, and if necessary black black thermal transfer sheets and performing thermal transfer according to each color. Instead of using the thermal transfer sheet of each color as described above, a thermal transfer sheet having an area formed by separately coating each color as shown in FIG. 4 is used. First, the yellow color separation image is thermally transferred using the yellow area. Then, thermal transfer is performed using the red area of the thermal transfer sheet, and then, by repeating the thermal transfer in sequence, the method of thermally transferring the color separation images of yellow, red, indigo, and black if necessary is adopted. There is an advantage that the replacement of is unnecessary. 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 image receiving sheet, and the heat energy.

By using the thermal transfer sheet of the present invention in combination with a thermal transfer image receiving sheet, printing using various printers of thermal printing system, facsimile, or printing of photographs by a magnetic recording system or printing from a television screen. It can be used for creating etc. For example, one screen of the received television is stored in a recording medium such as a magnetic tape or a magnetic disk as signals of color separation patterns of yellow, red, indigo, and black if necessary, and stored. A signal of each color separation pattern is output, and thermal energy corresponding to this signal is applied to the superposed body of the thermal transfer sheet and the thermal transfer image receiving sheet by the above-mentioned heat source such as a thermal head, and thermal transfer is sequentially performed for each color, The screen of the television can be reproduced as a sheet-shaped hard print. When a combination of a thermal transfer image-receiving sheet and the thermal transfer sheet of the present invention is used to print out such a television screen, a white dye-receiving layer alone or a colorless and transparent dye-receiving layer is usually used as the thermal transfer image-receiving sheet. It is convenient to form a reflection image by using a sheet backed by a base sheet such as paper or a white dye receiving layer backed by a base sheet such as paper.

The same operation as described above can be performed when a combination of characters, figures, symbols, colors and the like formed on a CRT screen by using a computer and a graphic pattern is used as an original picture. When the original image is a fixed image such as a painting, photograph, or printed matter or an actual object such as a person, still life, or landscape, an image is formed in the same manner as above by using an appropriate means such as a video camera. You can do it. Further, when generating 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.

EXAMPLES Next, the present invention will be described more specifically with reference to Examples and Comparative Examples. In the text, parts and% are based on weight unless otherwise specified.

Examples 1 to 41 A dye layer ink having the following composition was prepared and applied to a 6 μm-thick polyethylene terephthalate film having a heat-treated back surface so that the dry coating amount was 1.0 g / m ^2. It was dried to obtain the thermal transfer sheet of the present invention. Ink composition Any of the dyes of the formulas 1 to 4 described in the above table a ₁ part Any of the dyes of the formulas A to X described below a ₂ parts Other dyes (only when used) a ₃ parts Binder resin 4 parts methyl ethyl ketone _{(96-a 1 -a 2 -a} 3) / 2 parts toluene _{(96-a 1 -a 2 -a} 3) / 2 parts However, when the dye in the composition is insoluble in a solvent,
DMF, dioxane, chloroform or the like was appropriately used as a solvent.

Specific structural formulas of the dyes A to X used

[Chemical 7]

[0031]

[Chemical 8]

[0032]

[Chemical 9]

[0033]

[Chemical 10]

Next, synthetic paper (Yupo FPG # 150, manufactured by Oji Yuka) was used as the base sheet, and a coating solution having the following composition was applied to one surface of the synthetic paper at a rate of 10.0 g / m ² when dried. And then dried at 100 ° C. for 30 minutes to form a dye-receiving layer to obtain a thermal transfer image-receiving sheet. Polyester binder resin (Vylon 200, manufactured by Toyobo) 11.5 parts Vinyl chloride / vinyl acetate copolymer (VYHH, manufactured by UCC) 5.0 parts Amino-modified silicone (KF-393, manufactured by Shin-Etsu Chemical Co., Ltd.) 1.2 parts Epoxy-modified Silicone (X-22-343, manufactured by Shin-Etsu Chemical Co., Ltd.) 1.2 parts Methyl ethyl ketone / toluene / cyclohexane (weight ratio 4: 4: 2) 102.0 parts

Thermal Transfer Recording Test The thermal transfer sheet of the present invention and the thermal transfer image receiving sheet described above are overlapped with their dye layers and dye receiving surfaces facing each other, and a head applied voltage of 11 V and a printing time of 10 msec from the back surface of the thermal transfer sheet. ． Recording was performed with a thermal head under the conditions of the above, and the results shown in Tables 5 to 11 below were obtained. Storage test The above-mentioned thermal transfer sheet of the present invention was stored at 60 ° C for 60 hours. The surface condition of the dye layer after storage was observed, and the storage stability was determined according to the following criteria. ○: No deposition of dye was observed. B: Some precipitation of dye was observed. ×: A large amount of deposition of dye was observed. Density measurement The optical density meter R was used to measure the reflection density of the recorded thermal transfer image-receiving sheet.
It measured using D-918 (made by a Macbeth company). Light fastness test The light fastness of the image obtained by the thermal transfer test was carried out with a xenon fade odometer (Ci35A, manufactured by Atlas) (black panel temperature 50 ° C., 50 kLux). ○: No fading after irradiation for 50 hours. X: Discoloration is remarkable after irradiation for 50 hours.

[0036]

[Table 5]

[0037]

[Table 6]

[0038]

[Table 7]

[0039]

[Table 8]

[0040]

[Table 9]

[0041]

[Table 10]

[0042]

[Table 11]

Comparative Examples 1 to 23 The results shown in Table 12 below were obtained in the same manner as in Examples except that the materials for forming the dye layer were changed to the following. Ink composition Dye having the above structure a part Binder resin b part Methyl ethyl ketone (100-ab) / 2 parts Toluene (100-ab) / 2 parts

[0044]

[Table 12]

[0045]

[Effects] According to the present invention as described above, by using a specific binder resin as a binder component constituting the dye layer, the thermal transfer sheet itself has excellent storability, and a specific dye is used as a mixture. Therefore, even if heat energy is applied for an extremely short time, the color density,
It is possible to provide a thermal transfer sheet which gives a full-color image excellent in sharpness and light resistance. ,

[0046]

[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 view 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 ... Receiving layer 14 ... Thermal head 15 ... Platen roll

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Eguchi 1-1-1, Ichigayaka-cho, Shinjuku-ku, Tokyo Dai Nippon Printing Co., Ltd.

Claims (2)

[Claims] 1. A base sheet and a dye layer formed on the base sheet, wherein the binder component of the dye layer is a polycarbonate resin, a vinyl chloride / vinyl acetate copolymer, a styrene / acrylonitrile copolymer, A dye which is composed of a mixture of at least one resin selected from the group consisting of polyvinyl acetoacetal resin, phenoxy resin and ethyl cellulose resin and ethyl hydroxyethyl cellulose resin, and which is contained in the dye layer is represented by the following formula 1
~ At least one of the dyes represented by Formula 4, or the following Formula 1
~ A thermal transfer sheet, which is a mixture of at least one dye represented by Formula 4 and at least one dye represented by Formula A to Formula X below. 2. A substrate sheet and a dye layer formed on the substrate sheet, wherein the binder component of the dye layer contains at least an isocyanate-reactive cellulose, and the cellulose, an isocyanate-reactive acetal resin, and an isocyanate. At least one resin selected from the group consisting of a reactive vinyl resin, an isocyanate-reactive acrylic resin, an isocyanate-reactive phenoxy resin and an isocyanate-reactive styrene resin, and a cured product of a composition containing a polyisocyanate compound, The dye contained in the dye layer is at least one of the dyes represented by the following formulas 1 to 4, or at least one of the dyes represented by the formulas 1 to 4 and the formulas A to X below. A thermal transfer sheet, which is a mixture with at least one of the dyes described below. [Chemical 1] [Chemical 2] [Chemical 3] [Chemical 4] [Chemical 5] [Chemical 6] In the above general formula, R, X and Y represent the following substituents. R ₁ and R _{2 A} substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group or a substituted or unsubstituted aralkyl group. R ₃ substituted or unsubstituted alkyl group, substituted or unsubstituted alkoxy group, substituted or unsubstituted alkylcarbonylamino group, substituted or unsubstituted alkylsulfonylamino group, substituted or unsubstituted alkylaminocarbonyl group, substituted or An unsubstituted alkylaminosulfonyl group or a halogen atom. R ₄ substituted or unsubstituted alkoxycarbonyl group, substituted or unsubstituted alkylaminocarbonyl group, substituted or unsubstituted alkoxy group, substituted or unsubstituted alkyl group, substituted or unsubstituted cycloalkyl group, heterocyclic group or Halogen atom. R ₅ substituted or unsubstituted alkyl group, substituted or unsubstituted alkoxycarbonyl group, substituted or unsubstituted alkylaminocarbonyl group, substituted or unsubstituted alkoxy group, substituted or unsubstituted alkylaminosulfonyl group, substituted or non-substituted Substituted cycloalkyl group, cyano group, nitro group or halogen atom. R _{6 A} substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted amino group, a substituted or unsubstituted cycloalkyl group, a cyano group, a nitro group or a halogen atom. R _{7 A} substituted or unsubstituted alkyl group, a substituted or unsubstituted amino group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted alkoxycarbonyl group or a halogen atom. R _{8 A} substituted or unsubstituted aryl group, aromatic heterocyclic group, cyano group, nitro group, halogen atom or other electron withdrawing group. R ₉ CONHR ₁₀ , SO ₂ NHR ₁₀ , NHCOR ₁₁ ,
NHSO ₂ R ₁₁ or a halogen atom. R _{10 A} substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted aryl group or a substituted or unsubstituted aromatic heterocyclic group. R _{11 A} substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted amino group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted aromatic heterocyclic group. R _{12 A} substituted or unsubstituted alkyl group. R ₁₃ amino group or hydroxyl group. X halogen atom. A Y- substituted or unsubstituted aryl group, a substituted or unsubstituted aromatic heterocyclic group.