JPS63317386A - Thermal transfer sheet - Google Patents

Abstract

PURPOSE:To obtain a thermal transfer sheet having superior image density, light fastness, stain resistance, etc. and providing a monochrome or full color image, by a method wherein an area having no dye layer is provided adjacent to a dye layer. CONSTITUTION:In a thermal transfer sheet 10 consisting of a substrate film 1 and a dye layer 2 formed thereon, a colorless area 3 is provided adjacent to the dye layer 2. The dye layer 2 is formed by a method in which; a dye layer forming coating or ink is prepared by adding a dye, a binder resin, and other arbitrary components to an appropriate solvent and dissolving or dispersing the respective components, and applied on the substrate film 1 and dried. When a required image is a full color image, the dye layer 2 is made of Yellow, Magenta, and Cyan, (and Black, as necessary). In this manner, the colorless area 3 is formed adjacent to the dye layer 2 of the thermal transfer sheet 10, and a required image is formed. Thereafter, the image is thermally treated all over through the colorless area 3 so that a dye forming the image is sufficiently colored and fixed. In this manner, the image with superior image density, light fastness, stain resistance etc. is made available.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a thermal transfer sheet, and more specifically, it is useful for a thermal transfer method using a thermotransferable dye (thermally transferable dye), and has excellent image density and light fastness. The purpose of the present invention is to provide a thermal transfer sheet that can provide monocolor or full-color images with excellent color and stain resistance.

(Prior art) In place of conventional general printing methods and printing methods, have inkjet methods, thermal transfer methods, etc. been developed as methods for providing excellent monochrome or full-color images simply and at high speed? The so-called thermal transfer method, which uses heat-transferable dyes, is the most superior because it has excellent continuous gradation and can produce full-color images comparable to color photographs.

The thermal transfer sheet used in the above thermal transfer method has a dye layer containing a heat-transferable dye formed on one side of a base film such as a polyester film, and a dye layer containing a heat-transferable dye on one side of the base film to prevent the thermal head from sticking. Those with a heat-resistant layer provided on the other side are generally used.

The dye layer surface of such a thermal transfer sheet is placed on a transfer material having an image-receiving layer made of polyester resin, etc., and the dye in the dye layer is transferred to the transfer material by heating it in an imagewise manner from the back side of the thermal transfer sheet with a thermal head. The desired image is formed.

(Problem to be solved by the invention) In the conventional thermal transfer method as described above, very high-speed thermal transfer is required, so heating by the thermal head is performed for a very short time (m5e
c unit), the thermal head is required to have a high temperature.

On the other hand, if the temperature is too high, it may cause adhesion between the thermal transfer sheet and the transfer material or peeling of the dye layer, so the temperature is limited to a certain level.

As a result, the dye that has migrated to the transferred material cannot be sufficiently dyed into the transferred material, and some portions remain on the surface of the transferred material, resulting in the image not having sufficient color density. Furthermore, since the dye remains on the surface of the transfer material, there arise problems with the light fastness of the formed image and the so-called contamination that is transferred to other articles.

Therefore, there is a need for a thermal transfer sheet that can provide images of excellent quality without the problems described above.

(Means for Solving the Problems) As a result of intensive research in order to meet the demands of the prior art as described above, the present inventors have found an area (hereinafter referred to as 9) which does not have a dye layer adjacent to a dye layer on a base film. The present invention has been completed based on the discovery that the above-mentioned problems of the prior art can be solved by forming a colorless area (referred to as a colorless area) in the area.

That is, the present invention is a thermal transfer sheet formed by repeatedly forming dye layer regions on a continuous base film, characterized in that a colorless region is formed adjacent to the dye layer.

(Function) A colorless area is formed adjacent to the dye layer of the thermal transfer sheet, and after the desired image is formed, the entire image is heated through the colorless area to fully remove the dye forming the image. By coloring and dyeing, it is possible to provide an image having excellent image density, light fastness, stain resistance, etc.

Preferred Embodiments The present invention will now be described in more detail with reference to the accompanying drawings, which illustrate preferred embodiments of the invention.

FIG. 1 is a diagram schematically showing the basic structure of a thermal transfer sheet 10 of the present invention, and the thermal transfer sheet 10 of the present invention has a dye layer 2 formed on a base film 1 as shown in the first figure. This thermal transfer sheet is characterized in that a colorless area 3 is provided adjacent to the dye layer 2.

The continuous base film 1 of the thermal transfer sheet 10 of the present invention may be any film as long as it has a certain degree of heat resistance and strength, for example, 0.5 to 5.
Paper with a thickness of 0 μm, preferably about 3 to 10 μm, processed paper of each type, polyester film, polystyrene film, polypropylene film, polysulfone film,
Examples include aramid film, polycarbonate film, polyvinyl alcohol film, cellophane, etc., and polyester film is particularly preferred. The width of these base films is approximately the same as the width of the image to be formed, that is, the width of the transferred material, and may be, for example, the size of A plate or B plate, and the length is not particularly limited.

The dye layer 2 formed on the base film l as described above is
This is a layer in which the dye is supported by a binder resin of 0 to 0.

As the dye to be used, any dye used in conventionally known thermal transfer sheets can be effectively used in the present invention.
Not particularly limited. For example, some preferred dyes include MS Red G, Mac
rolex Red Violet R,Ccres
Red7B, Samaron Red l+l1sL
, S includes Lupine 5EGL, etc., and yellow dyes include Holon Brilliant Yellow S-6GL%.
PTY-52, Macrolex Yellow 5-6G, etc., and as a blue dye, Kaya Set Blue 1
4. Examples include Watasorin Blue AP-FW, Holon Brilliant Blue SR, MS Blue 100, Daito Blue No. 1, and the like.

As the binder resin for supporting the above dye, any conventionally known binder resin can be used, and preferred examples include ethyl cellulose, hydroxyethyl cellulose, ethyl hydroxy cellulose, hydroxypropyl cellulose, methyl cellulose, cellulose acetate, Cellulose resins such as cellulose acetate butyrate, polyvinyl alcohol, polyvinyl acetate, polyvinyl butyral,
Vinyl resins such as polyvinyl acetal, polyvinylpyrrolidone, and polyacrylamide, polyesters, and the like are preferred from the viewpoint of heat resistance and heat transferability of dyes.

The dye layer 2 of the thermal transfer sheet 10 of the present invention is basically formed from the above-mentioned materials, or may also contain various conventionally known additives as required.

Such a dye layer 2 is preferably made of 11
A dye layer-forming paint or ink is prepared by adding the dye, binder resin, and other optional components described in ff and dissolving or dispersing each component, and coating this on the base film 1 described above and drying it. Form.

The dye layer formed in this way is 0.2 to 5.0 μm.
m, preferably about 0.4 to 2.0 μm, and the dye in the dye layer accounts for a small amount of 5 to 90% by weight, preferably 10 to 70% by weight of the dye layer. It is preferred if the amount is present.

If the desired image is monochrome, the dye layer to be formed may be formed by selecting one color from among the listed dyes, or
If the desired image is a full color image, for example,
Appropriate cyan, magenta and yellow (and black if necessary) are selected to form yellow, magenta and cyan (further black if necessary) dye layers 2 as shown in the first figure. The area of these dye layers is preferably set to the size of the desired image, that is, the size of the transfer material, for example, the size of the A plate or the B plate.

A colorless region 3 adjacent to the monochrome or multicolor dye layer is formed. These regions can be easily formed by omitting application of the dye layer forming ink or coating liquid to only those portions when forming the dye layer. The colorless region 3 may be formed between one set of dye layer regions, that is, yellow, cyan, and magenta (or even black) as shown in the first figure, or may be formed between each color, and is not particularly limited. Although the area of these colorless areas 3 is not particularly limited, it is preferable that they have approximately the same area as the dye layer, that is, the area of the image to be formed.

The thermal transfer sheet of the present invention as described above exhibits sufficient performance as it is, but it may also be provided with an anti-adhesive layer, that is, a release layer, on the surface of the dye layer and in areas where there is no dye layer. A heat-resistant layer may be provided on the back side of the thermal transfer recording sheet of the present invention in order to prevent the effects of heat from the thermal head.

The transfer material used to form an image using the thermal transfer sheet as described above may be any material as long as its recording surface has dye receptivity to the above-mentioned dyes. If the material is paper, metal, glass, synthetic resin, etc. that does not have any properties, a dye-receiving layer may be formed on at least one surface thereof.

Examples of transfer materials that do not require the formation of a dye-receiving layer include polyolefin resins such as polypropylene, halogenated polymers such as polyvinyl chloride and polyvinylidene chloride, vinyl polymers such as polyvinyl acetate and polyacrylic ester, Polyester resins such as polyethylene terephthalate and polybutylene terephthalate, polystyrene resins, polyamide resins, copolymer resins of olefins such as ethylene and propylene and other vinyl resins,
Fibers made of ionomers, cellulose resins such as cellulose diacetate, polycarbonate, etc., woven 4ii,
Examples include films, sheets, molded products, etc. Particularly preferred are sheets or films made of polyester, or processed paper provided with a polyester layer.

In addition, in the present invention, even if the material to be transferred is non-stainable such as paper, metal, glass, etc., a solution or dispersion of the above-mentioned non-stainable resin is applied to the recording area and dried, or By laminating these resin films, it can be used as a transfer material. Even if the transfer material has the above-mentioned non-adhesive properties, a dye-receiving layer may be formed on the surface thereof from a resin that has good non-adhesive properties, as in the case of the above-mentioned paper.

The dye-receiving layer thus formed may be formed from a single material or from a plurality of materials, and may also contain various additives within the range that does not impede the purpose of the present invention. Of course.

Such a dye-receiving layer may be of any thickness, but typically has a thickness of 5 to 50 μm. Also, such a dye-receiving layer may preferably be formed as a continuous coating, or may be formed as a discontinuous coating using a resin emulsion or resin dispersion.

The thermal energy application means used when performing thermal transfer using the above thermal transfer sheet and the above recording material are as follows:
Any conventionally known means can be used, for example, by controlling the recording time with a recording device such as a thermal printer (for example, Video Printer VY-100 manufactured by 1 Ritsu Co., Ltd.), 5 to 100 mJ/mr.
A desired image is formed by applying thermal energy of the order of n'.

As mentioned above, images formed in this manner have problems with color density, light fastness, stain resistance, etc., but by using the thermal transfer sheet of the present invention, one of the above problems can be easily solved.

That is, after the image is formed, the colorless area of the transfer sheet is superimposed on the formed image, and in this state, the entire image is heated from above the colorless area using any heating means.
The dye forming the image is sufficiently colored and is dyed into the transferred material in one minute, resulting in an image with excellent color density, light fastness, and dyeing resistance.

As the first stage of heating, it is preferable to subsequently heat the entire surface using a thermal head, but it is also possible to use a heating roll or hot stand bar installed in the printer, or infrared irradiation. The heating temperature and heating time should be a temperature and time that do not excessively stick to the colorless area or the image (if the heating stage is a thermal head, the conditions may be the same as those for printing,
In the case of another single stage, a one-minute effect can be achieved by heating for several seconds at a temperature of about 50 to 200°C for about several minutes.

(Effects) According to the present invention, after forming a medium-color or multi-color image, the image is transferred through the colorless area of the thermal transfer sheet by one heating stage such as a thermal head, a hot roll, a hot plate or the like. By heating the image, it is possible to cause the dyes forming both images to develop color in one minute, and to change the color density and sharpness of the H+1+1 image toward IH.

In addition, as a result of the heat treatment, the dye forming the image is fully stained from the surface of the transfer material to the inside.
Since it is not directly exposed to external light, various fastnesses such as light resistance are improved.

In fact, there is virtually no free dye on the surface of the transfer material, so even if the screen adheres to other objects, it will not contaminate other parts.

Another unexpected effect in history is that the area where the dye layer is not formed is also used as a so-called blank area, and 4T is also used to prevent misalignment between the thermal transfer sheet and the transfer material, fine adjustment, etc. It is also useful for sheet feeding. For such purposes, the colorless area may be 6 widths narrower or wider than the dye layer.

Next, the present invention will be explained in a JL format with reference to examples.

In addition, in the text, parts or % are specified unless otherwise specified.
I put it up. These were dried and applied on a polyethylene terephthalate continuous film (Lumirror 5A-F53, manufactured by Toshi) with a width of 25.5 cm and a thickness of 4.5 μm (Lumirror 5A-F53, manufactured by Toshi), which had been heat-resistant treated on the back side, in the order shown in the first figure. ” or 1.0 each
g/rn” 25.5cm+X18.2cm
Apply yellow, magenta, and cyan in this order over an area of ,
A thermal transfer film of the present invention in the form of a continuous film having continuous dye layers of three colors, magenta and cyan, was obtained.

21 colors ni ayazet Blue714
1.00 copies Foron Br1lliant Blue
S-R4, 80 parts polyvinyl butyral resin
4.60 parts methyl ethyl ketone 44.
80 parts toluene 44.8
Part 0 Empress MS Red 6 2.86
Part Macrolex Red Violet R1,
56 parts Polyvinyl butyral resin 4.32 parts Methyl ethyl ketone 43.34 parts Toluene 42.92 parts Cyclohexanone 5.0 parts Foron Br1lliant Yellow
S-6GL 6.00 parts Polyvinyl butyral resin 4.52 parts Methyl ethyl ketone
4: 1.99 parts toluene
40.99 parts cyclohexanone
4.50 parts Next, synthetic paper (Yubo FPGI 50, manufactured by Tamago Yuka Co., Ltd.) was used as a base film, and a coating solution with the following composition was applied to one side of the paper at a dry rate of 4.5 g/rn'. The coated material was coated with 111 ml and dried at 100° C. for 30 minutes to obtain a transfer material used in the present invention.

Polyester resin (Vylon200, manufactured by Toyobo) 11.
5 parts vinyl chloride-vinyl acetate copolymer (VY song, 11c
C) 5.0 parts Amino-modified silicone oil (F-393, manufactured by Ietsu Chemical Co., Ltd.) 1.2 parts Epoxy-modified silicone oil (X-22-343, manufactured by Shin-Etsu Chemical Co., Ltd.) 1.2 parts Methyl ethyl ketone /toluene/cyclohexanone (weight ratio 4
:4:2) The cyan dye layer of the thermal transfer sheet of the present invention having three color dye layers and a colorless area on the 102-part recording surface and the above-mentioned transfer material are placed so that the cyan dye layer and the dye-receiving surface face each other. The images were combined and transferred from the back side of the thermal transfer sheet using a thermal head under the following conditions to obtain a cyan image. Next, magenta and yellow images were formed in the same manner, and then a colorless area was superimposed on each image surface, and the entire surface was printed with a thermal head under the following conditions and heat-treated.

For comparison purposes, both images of each of the three colors were formed without using a colorless area and without heat-processing the formed images. When the print density, light fastness and stain resistance of these images were compared, the results shown in Table 1 below were obtained.

Continuous dot density: 6 dots/mm Heating element resistance: 540Ω Applied energy: 2.0 mJ/dot Sheet feed speed: 5 mm/sec.

λ-1-hawk ((Print density) m Yellow Magenta Cyan Invention
1.35 1.30 1.43 Comparative example 1.
22 1,17 1.26 The print density was measured using a Macbeth densitometer.

(Lightfastness) Rule Yellow Magenta Cyan Invention
0.93 0.95 0.97 Comparative example 0.
860.880.93 In addition, the light resistance is the ratio of the concentration after 3rd grade irradiation and before irradiation, which is 5. +15 L Using the blue scale specified in 0841 <'l'j dyeability), 1lii ° Yellow Magenta Cyan Invention 0.09 0.12 0.17 Comparative example
0.17 0.28 0.37 In addition, (5 dyeing properties are printed surface and synthetic paper (YUPO FPG150, made from egg oil synthetic paper)
Place them together, apply a pressure of 20g/cm'' and heat at 60℃
The sample was left at 0% RH for 20 minutes, and the density of each color transferred to the surface of YUPO was measured.

Example 2 In addition to the three color inks used in Example 1, a black ink with the following composition was used to form dye layers and colorless areas in the order of black → cyan → magenta → yellow in the same manner as in Example 1. A thermal transfer sheet of the present invention was obtained.

Using this thermal transfer sheet, a four-color image was formed in the same manner as in Example 1, and heat treatment was similarly performed between heat rolls at 150°C at a sheet feeding speed of 5 strokes/sec through the colorless area. did.

Gura”-Saki Waxolinc 1lluc Ap-FW
: 1.60 copies Ccres fled 711
2.10 part Foron Br1
lliant Yellow S-6Gl, 2.
00 parts Polyvinyl butyral resin 4.60 parts Methyl ethyl ketone 44.80 parts Toluene 44.80 parts For comparison, a four-color image was formed without using the colorless area and without heat-treating the formed image. When the print density, light fastness and stain resistance of these images were compared, the results shown in Table 2 below were obtained.

The test method was the same as in Example 1.

(Print density) ■° Yellow Magenta Cyan Bootsque Invention 1.32 1.27 +, 40 1.2
8 Comparative example 1.22 1.17 1.26 1
．． 1: ] (Lightfastness) 111 Yellow Magenta Cyan B11 Invention
0.9+ 0.92 0.96 0.92 Comparative example 0.86 0.88 0. ! 13 0.
85 (Stainability) W Yellow Magenta Cyan Bootsque Invention 0.11 0.14 0.18 0.12
Comparative example Q, +7 0.28, 0.37
0.22 Example 3 The printing of each color in Example 1 was performed overlappingly on the same area of the transfer material to form a full-color landscape painting, and heat treatment was applied through the colorless area in the same manner as in Example 1. did. The obtained full-color image was significantly superior in image density and sharpness, and was also excellent in light fastness and stain resistance, as compared to an image that was not subjected to heat treatment.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a portion of the thermal transfer sheet of the present invention. 1: Base film 2; Dye layer 3; Colorless area Y: Yellow M; Magenta C; cyan Patent applicant: Dai Nippon Printing Co., Ltd. Agent: Patent Attorney Yoshi 1) Katsuhiro'',.'-゛

Claims (6)

[Claims] (1) A thermal transfer sheet formed by repeatedly forming dye layer regions on a continuous base film, characterized in that a region having no dye layer is formed adjacent to the dye layer. (2) Claim No. 1 in which the dye is a heat-transferable dye
) Thermal transfer sheet described in section. (3) The thermal transfer sheet according to claim (1), wherein the dye layer is composed of regions having different hues, and these hues are yellow, magenta, and cyan. (4) The thermal transfer sheet according to claim (1), wherein the dye layer is composed of regions having different hues, and these hues are yellow, magenta, cyan, and black. (5) The thermal transfer sheet according to claim (1), wherein the area of the dye layer and the area of the area without the dye layer are approximately the same. (6) The thermal transfer sheet according to claim (1), wherein a release layer is formed in an area that does not have a dye layer.