JP2506614B2 - Thermal transfer sheet for color image formation - Google Patents

Description

TECHNICAL FIELD The present invention relates to a thermal transfer sheet for color image formation, and more specifically, it is useful for proof printing of various color prints which have been widely used in the past. Thermal transfer sheet.

(Prior Art) Conventionally, a large amount of color printing is performed by offset printing, gravure printing, and the like. In such color printing, the original document is used as it is, or other original documents, characters,
Color separation is performed by combining symbols and the like to create a plate of the three primary colors of cyan, magenta and yellow, and if necessary, a black plate is added, and the hue, pattern, etc. of the original are reproduced with each printing ink. .

In order to print a large amount, it is necessary to confirm in advance whether the color tone, layout, characters, symbols, etc. of the original and the printed matter match exactly before printing a large amount. The process of printing is performed. With such proof printing, the color tone, layout, and
Although other differences are confirmed, the original and printed matter rarely completely match from the beginning, and the printing plate is corrected for each different point, and by repeating this process several times. , Manuscript and printed matter are well matched. Further, even when the original document is insufficient, the same operation is repeated to meet the request of the orderer.

(Problems to be Solved by the Invention) The proof printing process described above is an indispensable process when mass printing is performed, but this process is very complicated such as plate correction, and the proof printing process can be omitted. Alternatively, simplification is strongly demanded. However, at present, no means have been found to sufficiently meet these demands.

The present inventor has solved the above-mentioned problems of the prior art,
As a result of earnest research to meet the above-mentioned demand, the present invention has been completed by finding that the above-mentioned demand can be met by utilizing a conventionally known thermal transfer technique.

(Means for Solving Problems) That is, the present invention relates to a thermal transfer sheet for color image formation comprising at least three types of thermal transfer sheets having respective dye carrying layers containing dyes of respective hues of cyan, magenta and yellow. In the above, the cyan dye is a mixture of CI solvent blue 63 and a dye represented by the following formula (I), the magenta dye is a mixture of CI Disperse Red 60 and CI Disperse Violet 26, and a yellow dye. Is a dye represented by the following formula (II), which is a thermal transfer sheet for color image formation.

Next, the present invention will be described in more detail. The main feature of the present invention is that from the dyes for thermal transfer sheets which have been known innumerably in the past, the three primary colors of conventional printing inks, particularly offset printing inks, namely, cyan, magenta and The point is that the dye closest to the color tone of the yellow printing ink was selected and the thermal transfer sheet of each color tone was prepared.

Most of the three primary colors of conventional offset printing inks are composed of pigments, while the color materials used for the thermal transfer sheet are all sublimable (or heat transferable) dyes, so they both develop their colors. Due to the different mechanism, it was almost impossible to select a heat transferable dye that matches the three primary colors of the offset printing ink.

The present inventor further conducted research on selection of dyes that almost corresponded to the three primary colors of the printing ink. As for dyes other than yellow, the three primary colors of the printing ink were not reproducible with only one dye, but for cyan and magenta. Is
It was discovered that the three primary colors of printing ink can be reproduced by combining two specific types of dyes.

That is, in the present invention, as a cyan dye, CI
Solvent Blue 63 is combined with the dye represented by the above (I) (any of which may include a dispersant or the like, the same applies below), and the mixing ratio is preferably 2.0 to 8.0 of the latter per 1 part by weight of the former.
By using the mixture in the range of parts by weight, it is possible to reproduce the color tone corresponding to the cyan ink of the offset printing ink. If the mixing ratio is out of this range, the object of the present invention cannot be achieved sufficiently.

Further, as the magenta dye, CI Disperse Red 60 and CI Disperse Violet 26 are preferably mixed in a ratio of 0.3 to 1.0 parts by weight of the latter per 1 part by weight of the former to obtain an offset printing ink. It is possible to reproduce the color tone corresponding to magenta ink. If the mixing ratio is out of this range, the object of the present invention cannot be achieved sufficiently.

Further, by using the dye represented by the above formula (II) as the yellow dye, it is possible to reproduce the color tone corresponding to the yellow color of the offset printing ink.

The above CI Solvent Blue 63 is Kayaset Blue 71
4 (manufactured by Nippon Kayaku), the dye represented by the formula (I) is F
oron Brilliant Blue SR (sand), CI Dispers Red 60 is MS Red G (Mitsui Toatsu Chemicals), CI Dispers Violet 26 is Macrolex Red Violet
R (manufactured by Bayer), the dye represented by the formula (II) is F
It is commercially available as oron Brilliant Yellow S-6GL (made by Sand) and the like.

The present invention provides a thermal transfer sheet of three colors of cyan, magenta and yellow, respectively, utilizing the specific dye combination as described above, and these thermal transfer sheets of three colors are respectively different thermal transfer sheets. It may be a sheet, or may be formed by forming a dye-carrying layer containing a three-color dye in an arbitrary order on a continuous base material sheet, and further combining any of these embodiments with a conventionally known heat transfer sheet of any black color. It may be.

By using the thermal transfer sheet as described above, color separation of the original is performed with a color scanner before large-scale color printing by conventional offset printing, and a thermal transfer recording device equipped with a computer is connected to this to perform color separation. By printing and replacing it with a proof print, you can correct the color of printed matter, change the layout, insert symbols, letters, other originals, etc. The above process can finally determine.

The thermal transfer sheet of the present invention is characterized by using the above-described three-color dyes in a specific combination, and the other configuration may be the same as the configuration of a conventionally known thermal transfer sheet.

The base sheet used for the constitution of the thermal transfer sheet of the present invention containing the above dye may be any one as long as it has a conventionally known degree of heat resistance and strength, for example, 0.5 to 50 μm, preferably Paper having a thickness of about 3 to 10 μm, various types of processed paper, polyester film, polystyrene film, polypropylene film, polysulfone film, polycarbonate film, polyvinyl alcohol film, cellophane, etc., and particularly preferred is polyester film.

The dye carrying layer provided on the surface of the substrate sheet as described above,
This is a layer in which the above-mentioned dye is supported by an arbitrary binder resin.

As the binder resin for supporting the above-mentioned dye, any conventionally known one can be used, and preferred examples include ethyl cellulose, hydroxyethyl cellulose, ethyl hydroxycellulose, hydroxypropyl cellulose, methyl cellulose, cellulose acetate, and vinegar. Cellulose resins such as cellulose butyrate, polyvinyl alcohol, polyvinyl acetate, polyvinyl butyral, polyvinylpyrrolidone, vinyl resins such as polyacrylamide, polyesters, and the like are preferable from the viewpoints of heat resistance, migration of dyes, and the like.

The dye-carrying layer of the thermal transfer sheet of the present invention is basically formed of the above-mentioned materials, but may also contain various additives similar to conventionally known ones, if necessary.

Such a dye-carrying layer is preferably prepared by dissolving or dispersing each component by adding a dye, a binder resin and other optional components in each of the above combinations to an appropriate solvent to prepare a coating solution or ink for forming a supporting layer. Then, this is applied to the above-mentioned base material sheet and dried to form.

The support layer thus formed has a thickness of about 0.2 to 5.0 μm, preferably about 0.4 to 2.0 μm, and the dye in the support layer accounts for 5 to 70% by weight of the weight of the support layer, preferably Is preferably present in an amount of 10 to 60% by weight.

Although the thermal transfer sheet of the present invention as described above is sufficiently useful as it is for thermal transfer, an anti-adhesion layer, that is, a release layer may be further provided on the surface of the dye-carrying layer. Accordingly, it is possible to prevent adhesion between the thermal transfer sheet and the material to be transferred at the time of thermal transfer, to use a higher thermal transfer temperature, and to form an image with a further 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 excellent in release property such as silicone polymer, acrylic polymer or fluorinated polymer, 0.01 It can be formed by providing a release layer having a thickness of -5 μm, preferably 0.05-2 μm.

The inorganic powder or the releasing polymer as described above has a sufficient effect even if it is included in the dye-supporting layer.

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 material to be transferred used for forming an image using the thermal transfer sheet as described above may be any as long as its recording surface has dye acceptability for the dye, and In the case of non-containing paper, metal, glass, synthetic resin, etc., a dye receiving layer may be formed on at least one surface thereof.

As the material to be transferred which does not need to form the dye receiving layer,
For example, polyolefin resins such as polyethylene and polypropylene; halogenated polymers such as polyvinyl chloride and polyvinylidene chloride; vinyl polymers such as polyvinyl alcohol, polyvinyl acetate and polyacrylic ester; and 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, cellulose resins such as ionomers, cellulose diacetate and cellulose triacetate, fibers made of polycarbonate, polysulfone, polyimide, etc. , Woven fabric, film, sheet, molded product and the like.

Particularly preferred is a sheet or film made of polyester or a processed paper provided with a polyester layer. Further, paper, metal, glass and other non-dyeable transfer receiving materials may be coated and dried with a solution or dispersion of the above-described dyeable resin on the recording surface, or may be made of such a resin. The material to be transferred can be obtained by laminating the film.

Further, even with the transfer material having the above dyeing property, a dye receiving layer may be formed on the surface of the material having a more dyeing property as in the case of the above paper.

The dye receiving layer thus formed can be formed of a single material or a plurality of materials, and of course, may further contain various additives as long as the intended purpose is not hindered.

Such a dye-receiving layer may be of any thickness, but generally has a thickness of 5 to 50 .mu.m. 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 liquid.

Such a material to be transferred is basically as described above, and can be used as it is, but it is possible to include an inorganic powder for preventing adhesion in the material to be transferred or its dye receiving layer. By doing so, even if the temperature at the time of thermal transfer is further increased, adhesion between the thermal transfer sheet and the material to be transferred can be prevented, and more excellent thermal transfer can be performed. Particularly preferred is finely divided silica.

Further, instead of or in combination with the above-mentioned inorganic powder such as silica, a resin as described above having good releasability 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 used in an amount of about 0.5 to 3% by weight of the dye receiving layer.
The proportion occupying 0% by weight is good.

The transfer material to be used is, on the surface of the dye receiving layer,
An inorganic powder as described above may be adhered to enhance the anti-adhesion effect, or a layer made of a release agent having excellent release properties as described above may be provided.

Such a release layer has a sufficient effect at a thickness of about 0.01 to 5 μm, and can further improve the dye receptivity while preventing adhesion to the dye receiving layer of the thermal transfer sheet.

As the means for applying thermal energy used when performing thermal transfer using the thermal transfer sheet of the present invention and the recording material as described above, any conventionally known applying means can be used, for example, a thermal printer (for example, , Toshiba Corporation
5-100 m by controlling the recording time with a recording device such as a thermal printer TN-5400)
By applying thermal energy of about J / mm ² , the intended purpose can be sufficiently achieved.

(Operation / Effect) By using the thermal transfer sheet of the present invention as described above, color separation of an original document is performed by a color scanner prior to large-scale color printing by various printing methods, particularly offset printing method, By connecting a thermal transfer recording device equipped with a computer to this, performing color printing, and replacing this with a proof print, correction of the color of the printed matter, layout change, insertion of symbols, characters, other originals, etc. The final decision can be made by computer processing without creating or modifying the edition.
Therefore, by preparing the final plate in the state determined in this way, a complicated proof printing step as in the prior art is greatly simplified.

Next, the above will be described more specifically with reference to examples.
In the description, parts and% are based on weight unless otherwise specified.

Example 1 Three types of ink compositions for forming a dye carrying layer having the following compositions were prepared. The cyan and yellow ink compositions were prepared by dissolving the components and then filtering to remove insolubles. Each of these was applied to a polyethylene terephthalate film having a thickness of 9 μm and heat-treated on the back surface so that the dry coating amount was 1.0 g / m ² , and dried to obtain each of the three colors of cyan, magenta and yellow of the present invention. A thermal transfer sheet of was obtained.

Cyan color Kayaset Blue714 1.00 part Foron Brilliant BlueS-R 4.80 parts (containing dispersant) Polybutyral resin 4.60 parts Methyl ethyl ketone 44.80 parts Toluene 44.80 parts Magenta MS Red G 2.86 parts Macrolex Red Violet R 1.56 parts Polybutyral resin 4.32 parts Methyl ethyl ketone 43.34 parts Toluene 42.92 parts Cyclohexanone 5.0 parts Yellow color Foron Brilliant Yellow S-6GL 6.00 parts (containing dispersant) Polybutyral resin 4.52 parts Methyl ethyl ketone 43.99 parts Toluene 40.99 parts Cyclohexanone 4.50 parts Next, as a base material sheet, synthetic paper Yupo FP
G # 150), a coating liquid having the following composition was applied to one surface of the coating at a rate of 4.5 g / m ² when dried, and dried at 100 ° C. for 30 minutes to obtain a transfer-receiving material.

Polyester resin (Vylon200, Toyobo) 11.5 parts Vinyl chloride-vinyl acetate copolymer (VYHH, UCC) 5.0 parts Amino-modified silicone oil (KF-393, Shin-Etsu Chemical Co., Ltd.) 1.2 parts Epoxy-modified silicone cone oil (X- 22-343, manufactured by Shin-Etsu Chemical Co., Ltd.) 1.2 parts Methyl ethyl ketone / toluene / cyclohexanone (weight ratio 4: 4: 2) 102 parts The above-mentioned three-color thermal transfer sheet of the present invention and the above-mentioned transferred material are loaded with respective dyes. The layer and the dye receiving surface are laminated facing each other, and the head applied voltage is 10 V from the back surface of the thermal transfer sheet.
Recording was performed with a thermal head under a printing time of 4.0 msec., And three-color images were obtained. When the color rendering properties of these three color images were compared with a proof print image using a standard color of an offset printing ink (G set ink, manufactured by Morohoshi ink), good agreement was observed.

Example 2 In Example 1, three color dye-carrying layer forming inks were applied to one continuous sheet (the same substrate as in Example 1) in a constant area in the order of cyan, magenta, and yellow, and dried. A continuous sheet-shaped thermal transfer sheet for color image formation of the present invention was obtained in the same manner as in Example 1 except that the three colors were lined up on the continuous sheet in order.

Using this thermal transfer sheet, thermal transfer was continuously performed in the order of cyan, magenta, and yellow in the same manner as in Example 1 to form a color image. On the other hand, for comparison, a standard offset ink (G set ink, Morohoshi Ink) was used and a color image was formed from the same original by a proof press, and when compared with the above color image, it was indistinguishable to the naked eye. The color rendering properties of these two types of color images were as shown in FIG.

[Brief description of drawings]

FIG. 1 is a color image (A) according to the present invention obtained in Example 2 and a color image (B) using a standard offset ink.
Using a reflection densitometer (Macbeth RD-918), the density of each of the samples was measured with filters of blue-violet, green, and red.
It is a color circle created based on the method.

Claims (3)

(57) [Claims] 1. A thermal transfer sheet for color image formation comprising at least three types of thermal transfer sheets having respective dye carrying layers containing dyes of respective hues of cyan, magenta and yellow, wherein the cyan dye is CI solvent blue. 63 and a dye represented by the following formula (I), wherein the magenta dye is a mixture of CI Disperse Red 60 and CI Disperse Violet 26, and the yellow dye is represented by the following formula (II). A thermal transfer sheet for color image formation, which is a dye. 2. The color image forming apparatus according to claim 1, wherein the substrate sheet is a single sheet, and a dye carrying layer of three colors is formed on the surface of the sheet in any order. Thermal transfer sheet. 3. The thermal transfer sheet for color image formation according to claim 1, further comprising a black dye carrying layer.