JPH0392382A - Image receiving medium for sublimation type thermal transfer recording - Google Patents

Abstract

PURPOSE:To obtain the title image receiving medium eliminating image density irregularity or missing transfer and imparting high recording density by providing a microporous intermediate layer composed of a resin on a base material and providing a dyeing layer containing at least a substance easy to dye with respect to a sublimable dye thereon. CONSTITUTION:An intermediate layer having the so-called microporous sponge structure composed of a resin is provided on a base material and a dyeing layer composed of a substance easy to dye with respect to a sublimable dye is formed thereon. As the resin forming microporosity, for example, a nylon resin, a polyester resin, a vinyl chloride/vinyl acetate copolymer or the like are designated. The microporous structure of said resin is formed by such a method wherein a mixture of a non-volatile solvent not compatible with the resin and a volatile solvent different in a volatilization speed such as toluene is sufficiently mixed to be applied to the base material and the non-volatile solvent is subsequently eluted or a synthetic resin is foamed on the base material using a foaming agent.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an image receiving medium used in a sublimation thermal transfer recording method.

[Prior Art] The sublimation thermal transfer recording method has attracted attention in recent years as it is capable of recording excellent halftones and provides full-color hard copies that are close to color photographs.

The image receptor used for this recording is a paper base, particularly a synthetic paper base, coated with a thermoplastic resin that exhibits strong dyeability to sublimable dyes.

However, if a paper base with high surface smoothness and good base density uniformity, such as synthetic paper, is used, there is no problem, but when using a paper base (high-quality paper, coated paper) aimed at reducing costs, density unevenness may occur in the printed image. Problems such as transfer defects and transfer dropouts occurred, as well as low recording density.

Therefore, an image-receiving medium was proposed in which a cushion layer with specified elasticity was provided on the base and under the receptor layer (Japanese Patent Laid-Open No. 144394-1981).
However, it was still insufficient.

[Problems to be Solved by the Invention] The present invention provides a receiving medium for sublimation thermal transfer recording that does not have the above-mentioned drawbacks, that is, eliminates image density unevenness and transfer omissions, and has high recording density. The purpose is to

[Means for Solving the Problems] The structure of the present invention is to provide a microporous intermediate layer made of resin on a base material, and to coat the layer with a substance that is easily dyed by at least a sublimable dye. It consists of a sublimation type thermal transfer recording image-receiving medium characterized in that it is provided with a dyed layer containing.

The specific structure and operation are as follows.

As shown in Figure 1, the image-receiving medium of the present invention has an intermediate layer made of a resin having a microporous structure and a so-called sponge structure on a base material, and a sublimable dye is dyed on the intermediate layer. A dyed layer made of a easily dyed material is formed. Due to the heat from the thermal head, the sublimable dye in the dye transfer layer of the sublimation transfer recording medium sublimates and diffuses, and is transferred to the dyed layer of the image receiving medium. (For example, coated paper) Even if the smoothness and density uniformity are inferior to synthetic paper, the porous intermediate layer under the dyed layer in Figure 1 has a sponge structure, so the so-called cushion effect works, The head pressing from the base material of the sublimation transfer recording medium can evenly hit the contact interface between the dye transfer layer and the dyed layer, thereby preventing uneven image density and transfer omissions.

Examples of the resin that forms the microporous structure include nylon resin, polyester resin, acetal resin, phenol resin, acrylic ester resin, fluororesin, polycarbonate resin, epoxy resin, borisulfone resin, vinyl chloride resin, vinylidene chloride resin, and butyral resin. resin,
Examples include vinyl chloride-vinyl acetate copolymer.

As already known, (1) a nonvolatile solvent that is incompatible with the resin is mixed with a volatile solvent such as toluene or methyl ethyl ketone, which has a different volatilization rate. After thorough mixing, coating on a substrate and drying, a microporous structure is formed by eluting the non-volatile solvent either as is or if necessary with a solvent that does not dissolve the resin. (2) Using a blowing agent such as P,P"-oxybis(benzenesulfonylhydrazide), N'.N-dimethyl-N.N'-dinitrosoterephthalic acid amide, diazoaminobenzene, dinitrosobentamethylenetetramine, etc. The synthetic resin is foamed on a base material, or an inorganic powder such as salt or an organic powder such as starch is mixed into the resin, and then cured or solidified on the base material, and then treated with an elution solvent such as water. Examples include, but are not limited to, a method in which a fine porous network structure is formed by eluting the inorganic or organic powder.

As the nonvolatile solvent, animal and vegetable oils such as cottonseed oil, rapeseed oil, whale oil, and lanolin, or mineral oils such as motor oil, spindle oil, and dynamo oil are used.

Examples of the base material include known materials such as paper, synthetic paper, polypropylene film, and polyester film.

Further, there are no particular restrictions on the substance that is easily dyed by the sublimable dye used in the present invention, and conventionally known substances can be used.

[Example] The present invention will be explained in more detail with reference to Examples below.

Note that parts represent parts by weight.

Example 1 Vinyl chloride vinyl acetate copolymer VYHH (manufactured by Union Carbide) 20 parts Lanolin fatty acid oil 2 parts Solvent Methyl ethyl ketone 40 parts Toluene
40 parts The above mixed solution was thoroughly mixed and dispersed, and this solvent was applied to OK coat (manufactured by Oji Paper), an art paper with a thickness of about 100 μm, using a wire bar, and the drying temperature was 90°C.
The mixture was dried for 1 minute to form an intermediate layer having a porous structure of about 3 μm.

Next, a mixed solution having the following formulation was applied onto the intermediate layer using a wire bar, and dried at a drying temperature of 100° C. for 2 minutes to form a dyed layer with a thickness of about 3 μm.

Water-based polyester resin liquid (solid content 34±2%, trade name Pyronal MD-1200, manufactured by Toyobo) 90 parts Water-soluble silicone oil (solid content 38%, trade name SH490, manufactured by Toray Silicone) 10 parts Water 1
On the other hand, as a sublimation transfer sheet, an ink layer having the following formulation was coated to a thickness of about 1.5 μm on a 6 μm thick PET film provided with a silicone cured resin film of about 1 μm as a back layer to obtain a transfer medium.

Polyvinyl butyral resin (BX { / Sekisui Chemical Co., Ltd.) 10 parts Sublimation disperse dye for cyan (Kayaset 714 / Nippon Kayaku Co., Ltd.) 6 parts Solvent
Methyl ethyl ketone 45 parts toluene
45 copies The ink layer of the transfer medium thus obtained was superimposed so as to face the dyed layer of the image receiving medium, and an image was recorded from the back side of the transfer medium by changing the heating energy with a thermal head. As shown in Table 1, good results were obtained with high recording density and no transfer white spots. The recording density of the thermal head is 6 dots/I
II1, and the recording output was 0.42 W/dot.

Example 2 The same procedure as in Example was carried out except that the intermediate layer formulation was changed to the following.

Cellulose Acetate Ptylate CA8 381-0.5 (manufactured by Eastman Kodak)
20 parts rapeseed oil 2 parts solvent Methyl ketone 40 parts toluene
40 parts 1 The same results as in Example 1 were obtained.

Comparative Example 1 All procedures were carried out in the same manner as in Example 1, except that no intermediate layer was provided and the dyed layer formulation of Example 1 was directly applied onto art paper to form a dyed layer with a dry thickness of about 6 μm.

As a result, a decrease in recording density and transfer white spots occur.

Comparative Example 2 The same procedure as in Example 1 was carried out except that the intermediate layer formulation of Example 1 was changed to the following and no porous structure was formed.

Vinyl chloride-vinyl acetate copolymer V Y H H 2 0
Partial solvent: Methyl ethyl ketone gatiaAs a result, a decrease in recording density and transfer white spots occur.

Table 1 [Effects of the Invention] As is clear from the above description, the image receiving medium of the present invention has a microporous structure made of resin in the intermediate layer, so that the thermal head at the contact interface between the ink layer and the dyeing layer It is possible to improve the contact from the toner and prevent a decrease in recording density or occurrence of self-transfer omission.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the structure of each layer of an image-receiving medium and a recording medium of the present invention and their relationship, and FIG. 2 is a diagram showing image characteristics of the present invention and a comparative example.

Claims (1)

[Claims] A sublimation type thermal transfer characterized in that a microporous intermediate layer made of resin is provided on a base material, and a dyeing layer containing at least a substance that is easily dyed by a sublimable dye is provided on the intermediate layer. Image receiving medium for recording.