JPH0419191A - Image receiving medium for sublimation type thermal transfer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an image receiving medium for sublimation type thermal transfer.

[Prior Art] A sublimation type thermal transfer recording method using a thermal transfer recording medium having a transfer layer containing a thermally sublimable dye and an image receiving medium receiving the dye sublimated by thermal printing from the back side of the recording medium is an excellent method. It has been attracting attention in recent years as it is capable of recording halftones and provides full-color hard copies that are similar to color photographs.

Conventionally, the image-receiving medium used in this recording method consists of a dye-receiving layer made of a thermoplastic polyester resin, etc., which exhibits strong dyeability against heat-sublimable dyes, and a release agent, on a substrate (synthetic paper, etc.). The formed one is used.

[Problems to be Solved by the Invention] However, conventional image-receiving media do not necessarily have sufficient heat resistance, so the surface flatness of the dye-receiving layer deteriorates in the image-recording area after recording, especially in the high-image-density area where the applied energy is high. . This has the disadvantage that light scattering (epidermal diffusion) on the surface of the receptor layer increases and the clarity of the image decreases.

The less scattering of light on the surface of the receptor layer, the clearer the image, and in the case of a reflective image receiving medium, the lower the scattering of light, the higher the image density.

An object of the present invention is to provide an image-receiving medium that prevents deterioration of the surface smoothness of the receptor layer after recording and provides a clear and high image density.

[Means for Solving the Problems] As a result of intensive studies, the present inventors found that in order to prevent the flatness of the surface of the receptor layer from decreasing, it is not enough to improve the heat resistance of the receptor layer itself; Although it was discovered that heat resistance is necessary, it is difficult to use a substrate with high heat resistance due to cost and other considerations. Therefore, we conducted further studies and arrived at the present invention.

According to the present invention, there is provided an image-receiving medium for sublimation type thermal transfer, which is characterized in that a layer having higher heat resistance than the substrate and a dye-receiving layer are sequentially laminated on a substrate.

The specific structure and operation of the present invention are as follows.

In FIG. 1, the image-receiving medium of the present invention is comprised of an image-receiving substrate A, a dye-receiving layer B, and an intermediate layer C. That is,
The image-receiving medium of the present invention has a structure in which an image-receiving substrate A is laminated with an intermediate layer C having higher heat resistance than the substrate and a dye-receiving layer B capable of being dyed with a heat-sublimable dye.

Further, 1 indicates a thermal head, and the sublimation transfer recording medium is composed of a heat-resistant layer 2, a transfer substrate 3, and a dye transfer layer 4.

By heating from the thermal head 1, the heat sublimable dye is sublimated and diffused from the dye transfer layer 4 of the sublimation transfer recording medium, and the sublimated dye is transferred to the dye receiving layer B of the image receiving medium. The sublimation dye transferred to the image-receiving medium diffuses into the dye-staining resin forming the dye-receiving layer B and dyes the medium.

As described above, in conventional image-receiving media, the sharpness of the image decreases after recording due to a decrease in the flatness of the surface of the receptor layer, and the mechanism thereof is as follows. That is, during recording, the dye-receiving layer is deformed by the uneven surface of the thermal head, but at the same time, the underlying substrate with low heat resistance is plastically deformed.
Since the deformation is set by a decrease in temperature, the flatness of the surface of the receptor layer decreases. However, in the image receiving medium of the present invention, since a heat-resistant intermediate layer C (heat-resistant intermediate layer) is provided between the substrate A and the dye-receiving layer B, the substrate itself becomes plastic due to heating during recording. Since there is no deformation, deterioration in flatness of the surface of the receptor layer is suppressed.

In the present invention, a layer having higher heat resistance than the substrate is a layer mainly composed of a known resin whose glass transition point is higher than that of the substrate, or a layer containing a resin having a reactive functional group and a crosslinking agent or a curing agent. or a layer consisting of a radiation-curable resin.

Reactive functional groups include hydroxyl group, carboxyl group,
Amino groups, epoxy groups, etc. are the main ones, and resins with hydroxyl groups include cellulose derivatives, polyvinyl alcohol, polyvinyl alcohol derivatives, butyral resins, polyester resins, acrylic polyols, polyester polyols, polyether polyols, polyurethane polyols, and alkyd resins. Those with carboxyl groups include alkyd resins, cellulose derivatives, and polymers or copolymers of unsaturated carboxylic acids, and those with amino groups include melamine resins,
There are urea resins, etc., and there are various epoxy resins having epoxy groups.

As a crosslinking agent or curing agent to be used in combination with the above resins, the above resins having a functional group that can react with the functional group of the resin selected from the above resins can be used as a crosslinking agent or curing agent as is, as well as various types. Silane coupling agent, titanium coupling agent, zirconium chelating agent,
Aluminum chelating agent, M g SCa SZ n
Conventionally known crosslinking agents or hardening agents such as polyvalent metal compounds such as 1Pb, organic acids, inorganic acids, various inorganic and organic salts, metal soaps, and various polyamines can be used.

The radiation-curable resin that can be used in the present invention is a resin that is cured and crosslinked with radiation such as ultraviolet rays and electron beams. Such resins are composed of monomers, prepolymers, polymers, or mixtures thereof having at least one polymerizable unsaturated double bond in their structure, and optionally contain a photopolymerization initiator. These crosslinkable resins themselves are known. Note that the above resins may be used alone or in a mixture of several types. In addition, a known thermoplastic resin may be used in combination to impart bending resistance.

Examples of the dyeable resin used in the dye-receiving layer B of the present invention include known polyester resins, vinyl chloride resins, vinyl acetate resins, polycarbonates, butyral resins, and epoxy resins, one type or a mixture of several types, Alternatively, a copolymer may be used. Further, a curing reaction product of the above-mentioned resin and the above-mentioned crosslinking agent or curing agent may be used, or the above-mentioned radiation-curable resin may be used.

As the mold release agent used in the dye-receiving layer B, in addition to various modified silicone oils, conventionally known mold release agents such as silicone resins, silicone polyesters, and various fluorine-containing resins can be used alone or in combination.

The ratio of release agent to dyeable resin is approximately 0.1 to 30
Weight percent is preferred.

Note that the dye-receiving layer B can also contain a filler. Examples of fillers include white pigments such as silica, titanium oxide, and calcium carbonate, and the amount added thereof is preferably 5 to 80% by weight based on the amount of resin in the receiving layer. In addition, the dye-receiving layer may contain an interfacial lubricant, an ultraviolet absorber, an antioxidant, etc. as appropriate.

In addition, as the substrate A in the image receiving medium of the present invention, in addition to various plastic films, synthetic paper, art paper, high quality paper, coated paper, baryta paper, cellulose fiber paper, etc. can be suitably used alone or in a laminate thereof. used. For example, RC paper for photography is preferably used as the laminate.

The coating amount of the intermediate layer and the dye-receiving layer on the substrate is preferably 0.1 to 20 g/s2 in terms of solid content.

[Examples] Next, the present invention will be explained in more detail with reference to Examples. Note that all percentages and parts shown below are based on weight.

Example 1 A mixture having the following composition was sufficiently mixed and dispersed to prepare a coating liquid for an intermediate layer.

(Coating liquid for intermediate layer) Polymethyl methacrylate resin (trade name DIANAL BR-85: (Tg-105°C) Made by Mitsubishi Ray-E>'1m> 10
0 parts toluene 300 parts methyl ethyl ketone 300 parts Next, apply the above coating solution using a wire bar. White PET with a thickness of approximately 100μ■
Film (product name E20.

(manufactured by Toshi Corporation) and dried for 1 minute at a drying temperature of 110'C to form an intermediate layer with a thickness of about 4 μm.

Next, the following dye-receiving layer coating solution was applied onto the intermediate layer using a wire bar, dried at a drying temperature of 120"C for 1 minute to form a dye-receiving layer with a thickness of 3 μm, and further dried at 80"C for 50 hours. An image-receiving medium of the present invention was prepared by uniprocessing.

(Coating liquid for dye-receiving layer) Saturated copolymerized polyester resin (trade name Byron PCR926: manufactured by Toyobo Aji) 100
1 part isocyanate compound (Bahntsuk D-750, manufactured by Dainippon Ink Chemical Industries, Ltd.) 15 parts modified silicone oil (5H3746; manufactured by Toray Silicone ■) 5 parts toluene
300 parts methyl ethyl ketone
300 copies On the other hand, as a sublimation transfer recording medium, an ink layer with the following formulation (
That is, a coating liquid for the dye transfer layer was applied to a thickness of about 2 μm to obtain a transfer recording medium.

Polyvinyl butyral resin (trade name BX-1, manufactured by Tanezu Kagaku Co., Ltd.) Sublimation disperse dye for cyan (trade name Kayaset Blue 14 - manufactured by Nippon Kayaku Co., Ltd.) Methyl ethyl ketone 10 parts 6 parts 95 parts Toluene 95 parts Obtained transfer record The medium and the image-receiving medium were placed one on top of the other so that the ink layer of the transfer recording medium and the dye-receiving layer of the image-receiving medium faced each other, and image recording was performed by changing heating energy using a thermal head from the back side of the transfer recording medium. The recording density of the thermal head is 6 dots, and the recording output is 0.4
It was 2W/dot.

Example 2 An image receiving medium was prepared in the same manner as in Example 1, except that the following was used as the coating liquid for the intermediate layer in Example 1.
In addition, images were recorded.

100 parts of polyvinyl butyral resin (trade name BX-1, manufactured by Sekisui Chemical Co., Ltd.) 40 parts of butylated melamine resin (Super Beckamine L-145-80, manufactured by Dainippon Ink Chemical Industry Kan) 40 parts of crosslinking accelerator (Beccamin P-198) 0.2 parts polyether-modified silicone oil (SH3746; manufactured by Dainippon Ink & Chemicals)
5 parts toluene
320 parts methyl ethyl ketone
320 parts Example 3 As a coating solution for the intermediate layer, a solution consisting of 10 parts of a special acrylic ultraviolet curing resin (Unidaic C7-184, manufactured by Dainippon Ink Co., Ltd., 49% butyl acetate solution) and 4 parts of toluene was applied with a wire bar. After heating and drying, an image receiving medium was prepared in the same manner as in Example 1, except that it was irradiated with ultraviolet rays for 5 seconds using an 8017 cm ultraviolet lamp to form an intermediate layer with a thickness of about 4 μm, and an image was recorded. .

Comparative Example 1 Example 1 except that the intermediate layer was not provided in Example 1
An image receiving medium was prepared in the same manner as above, and an image was recorded.

Comparative Example 2 An image-receiving medium was prepared in the same manner as in Example 1, except that the following formulation was used as the coating liquid for the intermediate layer, and an image was recorded.

Polyester resin (trade name Pylon 600 (Tg-47℃); manufactured by Toyobo ■) 10
Table 1 shows the results of image recording using 0 parts toluene 300 parts methyl ethyl ketone 300 parts or more.

Table 1 Note 1) Maximum value of image density measured by Macbeth RD 918 type densitometer Note 2) eo@-eo" specular gloss on the surface of the dye-receiving layer in the image recording section The image on the image-receiving medium of the example has a high image density. , all were clear.

[Effects of the Invention] As explained above, since the image receiving medium for sublimation thermal transfer of the present invention is provided with an intermediate layer having higher heat resistance than the substrate, deterioration of the surface of the dye receiving layer after recording is suppressed. As a result, clear and high-density images can be obtained. It also has the advantage that curling of the image-receiving medium after recording is small.

[Brief explanation of drawings]

FIG. 1 is a schematic sectional view showing the image receiving mechanism of the sublimation type thermal transfer image receiving medium according to the present invention, and also includes a schematic sectional view of the sublimation transfer recording medium. A...Image receiving substrate, B...Dye receiving layer, C...Intermediate layer, 1...Thermal head, 2...Heat-resistant layer of transfer recording medium, 8...Transfer substrate of transfer recording medium , 4...Dye transfer layer of transfer recording medium.

Claims (1)

[Claims] 1. An image-receiving medium for sublimation thermal transfer, characterized in that a layer having higher heat resistance than the substrate and a dye-receiving layer are sequentially laminated on a substrate.