JPH06286345A - Heat transfer sheet - Google Patents

Abstract

PURPOSE:To make it possible to impart the record picture having the excellent properties of reproducibility in cyan color, coloring density, clear visibility and various fastnesses on an image receiving sheet by using the mixture of dyes, which are expressed by three kinds of the specified formulas, for the dye contained in a dye layer, which is formed on one surface of a base material sheet. CONSTITUTION:A heat transfer sheet is constituted of a base material sheet and a dye layer, which is formed on one surface of the base material sheet. The dye contained in the dye layer is to be the mixture of the dyes, which are expressed by the three kinds of formulas shown in the figure. The mixing ratio of the respective dyes is set in the following relationship. Namely, when the dye of the second formula containing NHCH3 is made to be a part X, 0<=x<=30 is set; the dye of the third formula containing NH2 is set as dye=(1-0.2x) to (15-0.5x) (0<=x<=5) and 0 to(15-0.5x) (5<=x<=30); and the dye of the first formula containing NHCOCH3 is set as dye = formula 1 + formula 2 + formula 3 = 100. Thus, the heat transfer sheet, which can readily impart the record picture having the excellent properties of reproducibility in cyan color, coloring density, clear visibility and various fastnesses in a manuscript copy on an image receiving sheet, can be obtained.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a thermal transfer sheet,
More specifically, it is an object of the present invention to provide a thermal transfer sheet which can easily give a recorded image excellent in cyan color reproducibility of a document and excellent in color density, sharpness and various fastnesses to an image receiving sheet.

[0002]

2. Description of the Related Art Conventionally, various sublimation-type thermal transfer methods have been known, and in recent years, due to advances in recording methods, a thermal head or the like has been used to provide a dye receiving layer on a polyester sheet or paper at high speed. It is possible to form delicate characters and figures or full-color photographic images on these image receiving sheets by using such image receiving sheets.

[0003]

In the above-mentioned prior art, when a full-color image of an original is reproduced by using the three primary colors of yellow, cyan and magenta, the transferred dye has an excellent coloring density and clear color. Properties and fastness are required, and for example, in the case of a cyan dye, it is required to develop a cyan color having a color tone that sufficiently matches the color development of other yellow and magenta colors.

Various dyes have been proposed to meet these demands. However, in the case of a dye excellent in color density, vividness and various fastnesses, in many cases, the matching property with other colors is unsatisfactory. In many cases, the full-color image of the original cannot be accurately reproduced after all. The requirement for this matching is not a problem that the color developability and sharpness of the dye should be good, and is an essential requirement when forming a full-color image even if the color developability of the dye is sacrificed to some extent.
Therefore, an object of the present invention is to provide a thermal transfer sheet which can easily give a recorded image having excellent reproducibility of cyan color of an original and excellent color density, sharpness and various fastness to an image receiving sheet. .

[0005]

The above object can be achieved by the present invention described below. That is, the present invention comprises a substrate sheet and a dye layer formed on one surface of the substrate sheet,
A thermal transfer sheet, wherein the dye contained in the dye layer is a mixture of a dye represented by the following formula (1) and a dye represented by the following formula (2) and / or (3). is there.

[Chemical 4]

[Chemical 5]

[Chemical 6]

[0006]

The dye of the above formula (1) shows a clear cyan color tone and an excellent heat transfer property as a dye for a heat transfer sheet and forms a high density and clear image. In addition, it does not match well with magenta color and is clear as compared with the original, and forms a slightly bluish full-color image, but is mixed with the dye represented by the formula (2) and / or (3). As a result, although the above-mentioned sharpness is lowered to some extent, the matching property with other colors is good, and it is possible to accurately reproduce the full-color image of the original document together with the yellow color and the magenta color.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Next, the present invention will be described in more detail with reference to preferred embodiments. A preferred mixing ratio of the dye of formula (1) and the dye of formula (2) and / or (3) is
When the amount of the dye of formula (2) is x parts by weight, an excellent hue can be obtained by setting the mixing ratio within the following range. When the dye of formula (2) is defined as x part, 0 ≦ x ≦ 30 dye of formula (3) = (1-0.2x) to (15-0.5)
x) (0 ≦ x ≦ 5) 0- (15−0.5x) (5 ≦ x ≦ 30) Dye of Formula (1) = Formula (1) + Formula (2) + Formula (3) = 10
The mixing ratio of the above dyes (1) to (3) is shown in FIG. If either one is too little or too much, matching with other colors becomes insufficient, which is not preferable. The thermal transfer sheet of the present invention is characterized by using the specific dye mixture as described above, and other configurations may be the same as those of conventionally known thermal transfer sheets.

The substrate sheet used for the thermal transfer sheet of the present invention may be any one as long as it has a conventionally known degree of heat resistance and strength, for example, 0.5.
Paper having a thickness of about 50 μm, preferably about 3 to 10 μm,
Various processed papers, polyester films, polystyrene films, polypropylene films, polysulfone films, polycarbonate films, aramid films, polyvinyl alcohol films, cellophane, etc., and particularly preferred are polyester films.

The dye layer provided on the surface of the substrate sheet as described above is a layer in which the dye mixture is supported by an arbitrary binder resin. As the binder resin for supporting the dye mixture, any conventionally known one can be used, and preferable examples include ethyl cellulose, hydroxyethyl cellulose, ethyl hydroxycellulose, hydroxypropyl cellulose, ethyl hydroxyethyl cellulose, methyl cellulose, Cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate,
Cellulose derivatives such as cellulose nitrate, polyvinyl alcohol, polyvinyl acetate, polyvinyl butyral, polyvinyl acetoacetal, polyvinyl pyrrolidone, polystyrene, vinyl resins such as polyvinyl chloride, polyacrylonitrile, acrylic resins such as polyacrylic acid ester, polyamide resin, Examples thereof include polyester resins, polycarbonate resins, phenoxy resins, phenol resins, epoxy resins, and air elastomers, which may be mixed or copolymerized and used, or may be crosslinked with various crosslinking agents. In particular, polyvinyl butyral and polyvinyl acetal are preferable from the viewpoint of heat resistance and dye migration. The dye layer of the thermal transfer sheet of the present invention,
Although it is basically formed of the above-mentioned materials, other organic fillers such as polyethylene powder and various additives similar to conventionally known ones may be included, if necessary.

Such a dye layer is preferably prepared by adding the above-mentioned dye mixture, binder resin and other optional components to a suitable solvent to dissolve or disperse each component to prepare a coating liquid or ink for forming the dye layer. Then, this is applied and dried on the above-mentioned substrate sheet to form. The dye layer thus formed has a thickness of 0.2 to 5.0 μm, preferably 0.4 to 2.
It has a thickness of about 0 μm, and the above-mentioned dye mixture in the dye layer is 5 to 70% by weight, preferably 1% by weight of the weight of the dye layer.
It is preferably present in an amount of 0 to 60% by weight.

The thermal transfer sheet of the present invention as described above is sufficiently useful as it is for thermal transfer. However, an anti-adhesion layer, that is, a release layer may be further provided on the surface of the dye layer. By providing the layer, it is possible to prevent the thermal transfer sheet and the image receiving sheet from sticking to each other during thermal transfer, use a higher thermal transfer temperature, and form an image with a more excellent density.

As this release layer, even if only an anti-adhesive inorganic powder is attached, a considerable effect is exhibited, and further,
For example, from a resin having excellent releasability such as a silicone polymer, an acrylic polymer, or a fluorinated polymer, 0.01 to
It can be formed by providing a release layer having a thickness of 5 μm, preferably 0.05 to 2 μm. In addition, even if the above-mentioned inorganic powder or releasing polymer is included in the dye layer, a sufficient effect can be obtained. Further, a heat-resistant layer may be provided on the back surface of such a thermal transfer sheet in order to prevent adverse effects due to the heat of the thermal head.

The image-receiving sheet used for forming an image by using the above-mentioned thermal transfer sheet may be any one as long as its recording surface has a dye-accepting property for the above-mentioned dye, and Paper, metal, which does not have dye receptivity
In the case of glass or synthetic resin, a dye receiving layer may be formed on at least one surface thereof.

Examples of the image-receiving sheet which does not need to form a dye-receiving layer include polyolefin resins such as polypropylene, halogenated polymers such as polyvinyl chloride and polyvinylidene chloride, vinyl such as polyvinyl acetate and polyacrylic ester. Polymers, polyester resins such as polyethylene terephthalate and polybutylene terephthalate, polystyrene resins, polyamide resins, copolymer resins of olefins such as ethylene and propylene with other vinyl monomers, cellulosic resins such as ionomers and cellulose diacetate. Examples include fibers, woven fabrics, films, sheets, and molded products made of polycarbonate, etc.

Particularly preferred is a sheet or film made of polyester or processed paper provided with a polyester layer. Even for non-dyeing image-receiving sheets such as paper, metal, glass, etc., a solution or dispersion of the above-mentioned dyeing resin is applied to the recording surface and dried, or a resin film thereof is used. An image-receiving sheet can be obtained by laminating the.

Further, even in the above-mentioned dye-receptive image-receiving sheet, a dye-receptive layer may be formed on the surface of the image-receptive sheet, as in the case of the above paper, from a resin having a better dyeing property. The dye-receptive layer thus formed is
Further, it may be formed from a plurality of materials, and it is a matter of course that various additives may be included within the range not impairing the intended purpose.

Such a dye receiving layer may have any thickness, but is generally 3 to 50 .mu.m thick. Further, such a dye receiving layer is preferably a continuous coating, but it may be formed as a discontinuous coating by using a resin emulsion or a resin dispersion. Such an image-receiving sheet is basically as described above and can be used satisfactorily as it is. However, the image-receiving sheet or its dye-receiving layer should contain inorganic powder for preventing tackiness. By doing so, even if the temperature at the time of thermal transfer is raised, the adhesion between the thermal transfer sheet and the image receiving sheet can be prevented, and more excellent thermal transfer can be performed. Particularly preferred is finely divided silica.

Further, in place of or in combination with the above-mentioned inorganic powder such as silica, a resin having good releasability as described above may be added. Particularly preferable releasing polymer is a cured product of a silicone compound, for example, a cured product of an epoxy-modified silicone oil and an amino-modified silicone oil. Such a release agent is preferably contained in an amount of about 0.5 to 30% by weight based on the weight of the dye receiving layer.

Further, the image-receiving sheet to be used may have the above-mentioned inorganic powder adhered to the surface of the dye-receiving layer to enhance the tack-preventing effect, and it has excellent releasability as mentioned above. You may provide the layer which consists of a mold release agent. Such a release layer exerts a sufficient effect with a thickness of about 0.01 to 5 μm, and can prevent the adhesion of the thermal transfer sheet to the dye receiving layer and further improve the dye receiving property.

As the means for applying the thermal energy used when performing thermal transfer using the thermal transfer sheet of the present invention as described above and the recording material as described above, any conventionally known applying means can be used. By controlling the recording time with a recording device such as a printer (for example, Hitachi, video printer VY-100), 5 to 5
By applying thermal energy of about 100 mJ / mm ² , the intended purpose can be sufficiently achieved.

[0021]

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. Example A dye layer-forming ink composition 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 and dried. The thermal transfer sheets of the present invention shown in Table 1 below were obtained. Dye mixture of the dye (1) and the formula (2) and / or (3) (mixing ratio is as shown in Table 1 below) 3.0 parts in total Polyvinyl butyral resin 4.5 parts Methyl ethyl ketone 46.25 parts Toluene 46.25 parts However, when the dye mixture is insoluble in the above solvent in the above composition, DMF, dioxane, chloroform or the like was appropriately used as the solvent.

Next, a synthetic paper (Yupo FPG # 150, manufactured by Oji Yuka) was used as a 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 obtain an image receiving sheet. Polyester resin (Vylon200, Toyobo) 11.5 parts Vinyl chloride / vinyl acetate copolymer (VYHH, UCC) 5.0 parts Amino-modified silicone (KF-393, Shin-Etsu Chemical Co., Ltd.) 1.2 parts Epoxy-modified Silly Corn (X-22-343, manufactured by Shin-Etsu Chemical Co., Ltd.) 1.2 parts Methyl ethyl ketone / toluene / cyclohexanone (weight ratio 4: 4: 2) 102.0 parts

The above-mentioned thermal transfer sheet of the present invention and the above-mentioned image receiving sheet are superposed with their dye layers and dye receiving surfaces facing each other, and the head applied voltage 10 is applied from the back surface of the thermal transfer sheet.
V, printing time 4.0 msec. Recording was performed with a thermal head under the conditions of, and the results shown in Table 1 below were obtained.

[0024]

[Table 1]

[0025]

[Effects] According to the present invention as described above, when a full-color image is formed by using a specific dye mixture as a dye of a thermal transfer sheet, the balance with other yellow and magenta colors is good, and The full-color image of the original can be accurately reproduced.

[0026]

[Brief description of drawings]

FIG. 1 CIE 19 of images of Example 1, Comparative Examples 1 and 2.
76 (L ^* a ^* b ^* ) Figure showing a uniform perceptual color space (a ^* , b ^* ) (measurement was performed with MINOLTA CR-221)

2 is a CIE19 of images of Example 1 and Comparative Examples 1 and 2; FIG.
76 (L ^* a ^* b ^* ) Figure showing uniform perceptual color space (L ^* , a ^* ) (Measurement was performed with MINOLTA CR-221)

FIG. 3 is a CIE19 of images of Example 1 and Comparative Examples 1 and 2;
76 (L ^* a ^* b ^* ) uniform perceptual color space (L ^* , b ^* ) (measurement was performed with MINOLTA CR-221)

FIG. 4 is a diagram showing a preferable mixing ratio of dyes in the present invention.

Claims (2)

[Claims] 1. A substrate sheet and a dye layer formed on one surface of the substrate sheet, wherein the dye contained in the dye layer is a dye represented by the following formula (1) or a compound represented by the following formula: A thermal transfer sheet, which is a mixture with the dye represented by (2) and / or (3). [Chemical 1] [Chemical 2] [Chemical 3] 2. The thermal transfer sheet according to claim 1, wherein the mixing ratio of the dye represented by formula (1) and the dye represented by formula (2) and / or (3) is a weight ratio having the following relationship. When the dye of formula (2) is defined as x part, 0 ≦ x ≦ 30 dye of formula (3) = (1-0.2x) to (15-0.5)
x) (0 ≦ x ≦ 5) 0- (15−0.5x) (5 ≦ x ≦ 30) Dye of Formula (1) = Formula (1) + Formula (2) + Formula (3) = 10
0