JPH01286892A - Transfer material for thermal recording - Google Patents

Abstract

PURPOSE:To enable repeated use of the subject material and reduce running cost, by a construction wherein a sublimable dye in an intermediate coloring material layer is transferred through diffusion into a coloring material layer simultaneously when the sublimable dye in the coloring material layer is transferred through sublimation to a dyeable resin layer of an image-receiving material for thermal recording, whereby the coloring material layer is supplied with the sublimable dye. CONSTITUTION:A transfer material 6 for thermal recording has a three-layer structure constituted basically of a base 2, an intermediate coloring material layer 3 comprising a heat- sublimable or evaporable dye and a binder resin, and a coloring material layer 4. When the transfer material 6 is superposed on an image-receiving material 5 and selective heating is conducted by a thermal head 1, the dye is transferred from the coloring material layer 4 to the image-receiving material 5 through sublimation to form an image, and simultaneously, the dye is transferred through diffusion from the intermediate coloring material layer 3 into the coloring material layer 4, whereby the loss of the dye due to the transfer of the dye from the coloring material 4 to the image-receiving material 5 can be made up for, and the transfer material 6 can be used repeatedly. The intermediate coloring material layer 3 is extremely effective for preventing color density from being lowered due to the loss of the dye in the coloring material layer 4 in multiple-time use of the transfer material, and for obtaining a required color density.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a transfer body for thermal recording, and particularly to a transfer body for thermal recording suitable for multiple uses.

(Prior Art) With the recent spread of personal computers, televisions, video tape recorders, etc., the demand for color printers that make hard copies of these color images is increasing. Recording methods for this color printer include an inkjet method, an electrophotographic method, a thermal transfer method, etc., but the thermal transfer method is often used because it is noiseless, easy to maintain, and can be miniaturized. This thermal transfer method is a method in which a heat-sensitive recording transfer member having a coloring material layer formed on a substrate and an image receptor are superimposed, and an arbitrary image is formed by heating with a laser, a thermal head, or the like. There are two types of thermal transfer methods: heat-melting and heat-sublimation, depending on the transfer method of the coloring material.
Divided into methods. That is, the heat-melt type is a method in which a heat-melt ink consisting of a pigment or dye and a heat-melt walrus is used as a coloring material, and the heat-melt ink is transferred by heating. On the other hand, the thermal sublimation type consists of a sublimable dye and a binder resin as coloring materials, and only the sublimable dye is transferred by heating. At this time, the sublimable dye sublimates in response to the amount of heat applied, making it easy to obtain halftones, and is considered the most suitable method for full-color printers.

As a thermal recording transfer body used in this sublimation type thermal transfer method, one in which a sublimable dye is provided together with a binder resin such as a polyester resin, an epoxy resin, or a polyamide resin is known (Japanese Patent Application Laid-open No. 14994/1983). .

[Problems to be Solved by the Invention] In all of the above-mentioned transfer bodies for sublimation type heat-sensitive recording, when printing is performed by heating with a thermal head etc., most of the dye in the coloring material layer is used, and printing is performed only once. I can't. In other words, the above-mentioned conventional technology does not give any consideration to the repeated use of the heat-sensitive recording transfer body, and the heat-sensitive recording transfer body is discarded after printing only once, leading to the problem of high running costs. there were.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a transfer body for heat-sensitive recording that can reduce running costs by making it possible to repeatedly use a transfer body for sublimation-type heat-sensitive recording, which has conventionally been disposable.

[Means to solve the problem]

The above problem is solved in a thermal recording transfer body in which a color material layer containing a dye that sublimes or vaporizes due to heat and a binder resin is provided on a substrate, and a dye and a binder that sublimates or vaporizes due to heat are placed between the substrate and the color material layer. This problem can be solved by providing an intermediate color material layer made of resin.

[For production]

The thermal recording transfer member (6) in the present invention basically includes a substrate (2), an intermediate coloring material layer (3),
It has a three-layer structure including a coloring material layer (4) and a coloring material layer (4). Further, as shown in FIG. 2, a boundary layer (7) may be further provided between the intermediate color material layer (3) and the color material N (4). However, in FIG. 1, (1) indicates a thermal head, and (5) indicates an image receptor.

When the transfer body (6) for thermal recording of the present invention is overlapped with the image receptor (5) and selectively heated by the thermal head (1), the dye is transferred from the color material layer (4) to the image receptor (5). At the same time as the dye sublimates and migrates to form an image, the dye diffuses and migrates from the intermediate coloring material layer (3) to the coloring material layer (4), thereby migrating from the coloring material N (4) to the image receptor (5). This makes it possible to compensate for the decrease in the amount of water and make it possible to use it repeatedly.

The intermediate coloring material layer (3) in the thermal recording transfer body (6) according to the present invention prevents a decrease in color density due to a decrease in dye in the coloring material layer (4) when used many times, Very effective for obtaining color density.

According to the research of the present inventor, the above effect is influenced by the dye content in the intermediate coloring material N (3), and is usually 2 to 20 times the dye content in the coloring material layer (4), preferably 3 to 20 times by weight. It was found that the above effect was sufficiently developed when the amount was 10 times the weight. The transfer of the dye from the intermediate coloring material layer (3) to the coloring material layer (4) depends on the sublimability of the dye used and the configuration of the intermediate coloring material layer (3) and the coloring material layer (4), respectively. Although it varies slightly depending on the thickness, amount and type of resin used, etc.
By setting the dye content in the intermediate coloring material layer (3) within the above range, in other words, by appropriately determining the dye content from the above range, the coloring material layer (3) can be successfully removed from the intermediate coloring material layer (3). 4) was found to be achieved. At this time, if the amount of dye in the intermediate color material layer (3) is small, 2
When printing @ eyes, sufficient dye is not supplied to the coloring material layer (4), which tends to cause a decrease in color density.On the other hand, if the amount of dye in the intermediate coloring material layer (3) is too large, During the second printing, more dye than necessary is replenished into the color material layer (4), which tends to lead to an increase in color density.

As the substrate (2) that can be used in the present invention, paper and various resin films can be used, and examples include capacitor paper, polycarbonate film, polyimide film, and polyester film. Further, if necessary, a heat-resistant layer may be provided on the surface that contacts the thermal head (1).

Next, the intermediate coloring material N (3) and the coloring material layer (4) according to the present invention are composed of a dye that sublimes or (and) vaporizes by heat, and a binder resin. Examples of the binder resin include polyester resin, polyamide resin, epoxy resin, etc. Examples include, but are not limited to, resins, polycarbonate resins, butyral resins, acrylic resins, and the like. Here, the binder resin used for the coloring material layer (4) is preferably a resin that is incompatible with the binder resin used for the intermediate coloring material layer (3) because it forms a layer on the intermediate coloring material layer (3). Furthermore, the binder resin used in the intermediate color material layer (3) may be cured using an appropriate crosslinking agent if necessary, and the dye used may be a sublimation or vaporizable dye that has been conventionally used in this type of field. Both can be used. The dye concentration itself in the color material layer (4) may be the conventional concentration, usually 10% by weight to 8%.
0% by weight, preferably about 20% to 50% by weight, and the thickness of the core layer is normally 0.5 μm to 50% by weight.
The thickness is about 5 μm, preferably about 0.5 μm to 2 μm.

The thickness of the intermediate color material layer (3) may be appropriately determined depending on the dye concentration in the core layer, but is usually about 0.5 μm to 5 μm, preferably about 0.5 μm to 2 μm. Intermediate color material layer (3
) and the color material layer (4) may be of the same type or different types.

In addition, in the present invention, the intermediate coloring material layer (3) and the coloring material layer (4)
A boundary layer (7) may be provided for the purpose of preventing dissolution and mixing of the lower layer by a solvent during lamination between the boundary layer (7).
), for example, cellulose resin, silicone resin, fluororesin, etc., and the thickness thereof is usually 0.05 μm.
m to 1 μm, preferably about 0.1 μm to 0.5 μm.

When manufacturing the transfer body of the present invention, there is basically no difference from the manufacturing method of conventional transfer bodies, except that the predetermined intermediate color material layer (3) is provided between the substrate (2) and the color material layer (4). ) and a boundary layer (7) if necessary.

〔Example〕

Hereinafter, one embodiment of the present invention will be described in detail, but the present invention is not limited to this embodiment.

In addition, parts in the examples indicate parts by weight.

Example 1 Basic disperse dye with sublimation property (Lurafix Bl
An ink solution consisting of 15 parts of ue660 (manufactured by BASF), 5 parts of polyamide resin (Persalon 1140, manufactured by Henkel Hakusui), 40 parts of toluene, and 40 parts of isopropyl alcohol was dispersed in a ball mill for 24 hours, and then bared onto a 6 μm polyester film. The dry coating amount with the coater is Ig.
/n() and dried to form an intermediate coloring material layer.Furthermore, a basic disperse dye (Lurafix Blue) was applied and dried to form an intermediate coloring layer.
An ink liquid consisting of 5 parts of Vylon #200 (manufactured by BASF Co., Ltd.), 15 parts of a saturated linear polyester resin (Vylon #200, manufactured by Toyobo Co., Ltd.), 40 parts of toluene, and 40 parts of methyl ethyl ketone was dispersed in a ball mill for 24 hours to obtain the above intermediate color material. A coloring material layer was formed by coating the layer with a bar coater so that the dry coating amount was Ig/% and drying to prepare a transfer material for heat-sensitive recording.

On the other hand, saturated linear polyester resin (Vylon #200,
A dyeing resin solution consisting of 20 parts (manufactured by Toyobo Co., Ltd.), 3 parts of a polyisocyanate compound (Coronet 1-L, manufactured by Nippon Polyurethane Co., Ltd.), and 77 parts of methyl ethyl ketone was applied in a dry coating amount of 1.
0 g/rrr on polypropylene synthetic paper using a reverse coater and drying to form a dyed resin layer.
Furthermore, on top of this, ultraviolet curable silicone resin (X-627
223 (manufactured by Shin-Etsu Chemical Co., Ltd.) using a bar coater at a concentration of 0.5 g/rrf, and then using a high-pressure mercury lamp (80 g/rrf).
A heat-sensitive recording image receptor was prepared by irradiating the film at 0 W for 30 seconds and curing it.

Using the thermal recording transfer body and image receptor thus obtained, the thermal head recording conditions were 6 dots/applied power of 0.4 W.
/ dot, pulse width 15ms, color printer,
When the pattern was printed repeatedly five times, the color densities shown in Table 1 were obtained. Color density was measured using a color reflection densitometer DM-400 (manufactured by Dainippon Screen Mfg. Co., Ltd.).

Example 2 In Example 1, an intermediate coloring material layer of a transfer body for thermal recording was prepared using the following formulation.

Basic disperse dye (B-136 manufactured by Nippon Kayaku Co., Ltd.) 15 parts Saturated linear polyester resin (Vylon #200 manufactured by Toyobo Co., Ltd.) 5 parts Toluene
40 parts MEK (methyl ethyl ketone) 40 parts A color material layer was also prepared with the following formulation.

Basic disperse dye (B-136 manufactured by Nippon Kayaku Co., Ltd.) 5 parts Butyral resin (S-LEC BM-115 parts manufactured by Tank Suikagaku Co., Ltd.) Ethanol 40 parts Toluene
40 copies and other patterns were similarly printed using a color printer and the color density was measured.

Example 3 In Example 2, after creating the intermediate color material layer, a composition consisting of 10 parts of ethyl cellulose, 30 parts of toluene, and 60 parts of isopropyl alcohol was applied using a bar coater at a dry coating amount of 0.2 g/rT? A boundary layer was created by coating and drying to give the following composition, and a coloring material layer was further formed on top of the boundary layer with the following formulation.

Basic disperse dye (B-136 manufactured by Nippon Kayaku Co., Ltd.) 5 parts Saturated linear polyester resin (Vylon #200 manufactured by Toyobo Co., Ltd.) 15 parts Toluene
40 part MEK
40 copies or less were printed in the same manner using a color printer, and the color density was measured.

Comparative Example 1゜In Example 1, on a 6 μm polyester film,
The dry coating amount of the ink liquid with the following composition is I using a bar coater.
A transfer material for heat-sensitive recording was prepared by coating and drying so as to give g/rrf, and thereafter a pattern was similarly printed using a color printer and the color density was measured.

Base-dispersible dye (Lurafix Blue 660 manufactured by Basf)
15 parts saturated linear polyester resin (Vylon #200 manufactured by Toyobo Co., Ltd.) 5 parts toluene
40 part MEK
40 copies Table 1 [Effects] As explained in detail above, according to the present invention, during printing by heating with a thermal head, etc., the sublimable dye in the color material layer is absorbed into the dyeing resin of the image receptor for thermal recording. At the same time as sublimation and transfer to the intermediate color material layer, the sublimable dye in the intermediate color material layer diffuses and transfers to the color material layer, and by replenishing the sublimation dye to the color material layer, it is possible to prevent a decrease in color density during multiple printings. This has a remarkable effect.

[Brief explanation of the drawing]

FIG. 1 shows a cross-sectional view of a simulated explanatory diagram when printing is performed using the transfer body for thermal recording of the present invention, and FIG. 2 shows a cross-sectional view of the transfer body for thermal recording according to one embodiment of the present invention. . 1...Thermal head 2...Base 3...Intermediate coloring material layer 4...Coloring material layer 5...Image receptor for thermal recording 6 ...Thermal recording transfer body 7...Boundary layer Fig. 1 Fig. 2

Claims (3)

[Claims] (1) In a heat-sensitive recording transfer body in which a coloring material layer containing a dye that sublimes or vaporizes by heat and a binder resin is provided on a substrate, the dye and binder that sublimates or vaporizes by heat are placed between the substrate and the coloring material layer. A transfer body for heat-sensitive recording, characterized in that it is provided with an intermediate coloring material layer containing a resin. (2) The transfer body for thermal recording according to claim 1, further comprising a boundary layer between the intermediate coloring material layer and the coloring material layer. (3) The transfer body for thermal recording according to claim 1 or 2, wherein the dye content in the intermediate coloring material layer is 2 to 20 times by weight the dye content in the coloring material layer.