JPH02233293A - Sublimation type thermal transfer recording medium - 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] 〔Technical field〕 The present invention relates to a sublimation type thermal transfer recording medium.

[Prior art]

Conventionally,! The binder resin used in A flower-type thermal transfer media is made of resins with a glass transition point (e.g., ethyl cellulose) in order to obtain high-performance images with as low energy as possible.
A binder resin with a low Tg) was used. However, when a transfer medium is stored for a long time with a binder resin having a low Tg, the dye aggregates, becomes particulate, or precipitates on the surface of the layer. When such a transfer medium is used to print on a transfer object, the image loses its sharpness, and the dye is directly transferred to the transfer object, causing background smudges and deterioration of image quality.

Furthermore, the dye deposited on the surface is transferred to the back surface of the transfer medium, staining the thermal head, and also causing a decrease in image density and a change in hue. In particular, in the laminated transfer medium of the present invention intended for multiple printing, the above-mentioned drawbacks are conspicuous because the dye concentration in the binder resin is high.

〔the purpose〕

The present invention overcomes the conventional drawbacks and provides a sublimation thermal transfer recording medium that has good multi-printing characteristics, does not reduce image density or image quality, and has improved storage stability. Let's call it "one target."

〔composition〕

The present invention replaces the conventional homogeneous ink layer provided on the substrate with
By adopting a multi-layer structure with functions separated into a relatively thin surface layer (transfer contribution layer) that has the function of sublimation transfer and a layer (dye supply layer) that has the function of diffusing and supplying sublimation dye to the surface layer, a large number of To provide a sublimation transfer recording medium that does not rapidly reduce print density even after multiple printings, prevents deterioration of image quality and background smudge, and has improved storage stability.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings. FIG. 1 is an explanatory diagram showing the structure of the sublimation type thermal transfer recording medium of the present invention, in which 1 indicates a substrate, 2 an ink layer composed of a dye supply M4 and a dye transfer contribution layer 5, and 3
6 indicates an image receptor such as paper, and 6 indicates a thermal head.

In the present invention, a dye supply layer and a transfer contributing layer are provided in order from the substrate side on the substrate, and the transfer layer 77
Multiple printing adjusted so that the amount of sublimable dye consumed by sublimation transfer from the layer through the free surface (m-order double amount/time/area) is easily diffused and supplied from the dye supply layer to the transfer contribution layer. A rising violet type thermal transfer recording medium (invention described in Japanese Patent Application No. 63-62866) having a good
Further improvements have been made in terms of scumming and storage stability.

The improvement of the present invention as described above uses a resin having a glass transition temperature (Tg) of 60 to 150°C as a binder for the dye transfer gathering layer, and a resin having a glass transition temperature (Tg) of 0 to 60°C as a binder for the dye supply layer.
This is accomplished by using a resin that has a glass transition temperature (Tg) of °C.

With such a structure, the dye in the dye supply layer using a binder resin with a low Tg can easily migrate, but since the surface is covered with a dye transfer contributing layer made of a binder resin with a high Tg, It has excellent storage stability and can prevent a decrease in image density and image quality.

However, if the Tg of the binder resin in the dye supply layer is too low, for example, below O'C, dye aggregation occurs, and conversely, image density decreases.

Furthermore, if the Tg of the binder resin of the dye transfer contribution layer is too high, for example, 150° C. or higher, the storage stability is good, but the image density decreases, probably due to poor dye diffusion.

Next, according to the present invention, in order to print as many times as possible with one transfer medium, the dye concentration in the dye supply layer should preferably be high to a certain extent, and the layer should be thick to a certain extent. In this case, the dye concentration is generally about 5 to 80%, preferably about 20 to 70%. Further, the thickness of the layer is generally 0.1 to 20 μm, 0.5 to 5 μm. Further, in terms of storage stability, the dye concentration of the dye transfer contribution layer is preferably low, and the layer thickness is preferably thin to a certain extent in order to prevent a decrease in image density. In this case, the dye concentration is generally about 5 to 80%, preferably about 10 to 60%.

Moreover, the thickness of the layer is generally 0.05 to 5 μm, preferably 0.1 to 2 μm.

The Tg that can be used for a sublimation thermal transfer medium with such a configuration is 6.
As the binder resin of 0'C to +50'C, high molecular weight 7 weight polyvinyl butyral, cellulose acetate, cellulose acetate 1-butylene 1-, polystyrene, vinyl chloride acetate bicopolymer, acrylic resin, epoxy resin, high molecular weight saturated polyester are used. , polycarbonate, phenoxy resin, etc.

Further, the binder resin having a Tg of 00C to 60C can be selected from low molecular weight polyvinyl butyral, ethyl cellulose, ethylene-vinyl acetate copolymer, low molecular weight saturated polyester, nylon resin, vinyl chloride resin, and the like.

Known sublimable dyes can be used in the dye supply layer and dye transfer contribution layer of the present invention.

A flower dye may be any dye that sublimes or vaporizes at 60°C or higher, and is mainly used in thermal transfer printing such as disperse dyes and oil-soluble dyes, such as C. I. Disperse yellow 1.3, 8, 9,]. 6,41. ,5
4,60,77,146 etc., C. ■． 1, 4, 6, l of Disverse thread 1\. ]. ,+5.17,55,5
9, 60, 73, 83, etc., C. I. Disperse Blue 3.14, 19, 26, 56, 60, 64, 72,
99, 108, etc., C. Ding. Sonorevent yellow 7
7,116 etc., C. I. Solventore 1-23.
25.27 etc.C. I. Solven 1 Blue 36.8
3,105, etc., and these dyes can be used alone or in combination of several kinds.

Further, as the base sheet 1-, a film such as a capacitor paper, a polyester film, a polystyrene film, a polysulfone film, a polyimide film, a polyamide film, etc. is used. A conventional adhesive layer or the like may be provided, and a conventional heat-resistant lubricant layer may be provided on the front surface of the base seal 1, if necessary.

Up until now, we have described an example in which the dye layer is divided into two layers, but
If an appropriate difference in the amount of dye transfer is created and the functional separation as intended by the present invention can be achieved, it is possible to form the dye layer into a multilayer of two or more layers.

The following explanations have been made based on a recording method using a thermal head, but the transfer medium of the present invention can be applied to a recording method in which recording thermal energy is applied by a method other than a thermal head, such as a thermal printing plate, a laser beam, Alternatively, it can also be used in a method that utilizes Joule heat generated by electricity in a medium such as a support and/or an ink layer. Among these, the so-called electrical thermal transfer method, which uses Joule heat generated in the medium, is the most well-known, for example, USP 4,103,0.
66, JP-A-57-14060, JP-A-57-11.0
80, or Japanese Patent Application Laid-Open No. 59-9096, and many other documents.

When used in this current transfer method, the support is made of relatively heat-resistant resins such as polyester, polycarbonate, triacetyl cellulose, nylon, polyimide, aromatic polyamide, etc., and aluminum, copper, iron, tin, etc. , supports in which metal powders such as zinc, nickel, molybdenum, silver, etc. and/or conductive powders such as carbon black are dispersed to adjust the resistance value to an intermediate value between that of an insulator and a good conductor; It is sufficient to use a support on which a conductive metal such as 1-7 is vapor-deposited or sputtered. The thickness of these supports is desirably about 2 to 15 microns in consideration of Joule heat conduction efficiency.

Further, when used in a laser beam transfer method, a material that absorbs laser beams and generates heat may be selected as the support. For example, a conventional thermal transfer film containing a light absorption heat conversion material such as carbon, or a film in which an absorbing layer is formed on the front and back surfaces of a support is used.

If necessary, a thin release layer made of a substance having lubricity and heat resistance may be provided on the dye transfer contributing layer 2, and a thin release layer made of a substance having lubricity and heat resistance may be provided between the dye supply layer and the dye transfer contributing layer. An intermediate layer may be provided in order to prevent unnecessary movement of the sublimable dye from the dye supply layer to the dye transfer contribution layer during non-recording (during storage).

EXAMPLES Hereinafter, the present invention will be explained in more detail based on the following examples, but the present invention is not limited thereto.

Example 1 [Dye supply layer formulation] Toluene: 100 methyl ethyl kene: 100 A composition having the above formulation was dispersed in a Pall mill for 24 hours.

[Dye transfer contributing layer prescription]

Juobe Dye KAYASET BLUE 714
7 Toluene ] 00 Methyl ethyl ketone 100 The silk composition of the above formulation was completely dissolved by stirring.

Using a wire bar, the above composition for the dye supply layer was applied to 8.5μ■-Boriimi 1 to Finolem (manufactured by Toray DuPont Salmon) to a film thickness of 2.5μIl1, and after drying,
Furthermore, a composition for dye transfer contributing layer is applied on top of the layer to a thickness of 0.6 μm.
A sublimation thermal transfer medium was obtained by coating and drying to obtain a sublimation thermal transfer medium.

Using this sublimation thermal transfer medium, image receiving paper (supply VY-SIOO for Hitachi Video Printer VY-50), thermal head 6 dots/mm, applied power 442 mJ/dot 1~, application time 0~8 mmsec, impression energy 0~
3. Printing was performed under the condition of 54 mJ/dot 1. Further, this sublimation thermal transfer medium was subjected to a 100-hour storage acceleration test in a constant temperature bath at 60° C. and 50% RH, and compared with that before storage. Furthermore, using a transfer medium that has been subjected to preservation promotion test I,
Printed in the same manner as above and compared the images. The results are shown in Table 1 below.
Shown below. (Measurement of image density is done using Macbeth Densitometer RD-51.
4) Hereinafter, the same procedure as in Example 1 was repeated except that the following formulations were used as the dye supply layer formulation and the dye transfer contribution layer formulation, and the obtained results are shown in Table 1 below.

Example 2 [Dye supply layer formulation] Dye KAYASET [3LIIE 71. /1 methanol [Dye transfer contributing layer formulation] Dye KAYASET BLUE 7] 4 Toluene Methyl Ethyl Chemical Example 3 Dye KAYASET I3L [JIE 7] 7 l Toluene Methyl Ethyl Ketone Polyvinyl Butyral, Ten Butyral Weight Parts Weight Parts 5000 A (Denki Kagaku Kogyo) (Company), Tg.713℃
) Dye KAYASET BLLIE 714 Toluene Methyl Ethyl Ketone Example 4 ]. 00 Dye KAYASET 13LtlE 7]. 4 Toluene methyl ethyl ketone [Dye transfer contributing layer formulation] Heavy cell L dye KAYASET BLUE 7] 4 Toluene methyl ethyl ketone dye KAYASET t'lLUE 7]. 4 Tetrahydrofuran Example 6 [Dye supply layer formulation] Part by weight dye KAYASET BLUE 7]. 4 Toluene Methyl Ethyl Ketone Example 5 [Dye supply layer formulation] Parts by weight Dye KAYASET BLLIE 7]. 41~Luene Methyl Ethyl Ke 1hen [Dye transfer contributing layer treatment] Vinyl chloride vinyl acetate resin, V Y' I{H parts by weight] 0 (manufactured by Union Carby 11, Tg. 72°C) Dye
KAYASET BLUE 714 7 Tetrahuman Furan 200 Table-1

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the structure of the Weihua type thermal transfer recording medium of the present invention. 1...Substrate 2...Ink layer 3...Image receptor 4...Dye supply layer 5...Dye transfer contributing layer 6...Thermal head [Effect] As stated in the following section By using a specific binder resin, the print density does not decrease even if the number of prints is increased, good gradation can be expressed, and the product has excellent storage stability.
Provided is a sublimation type thermal transfer recording medium that does not cause background stains or deterioration in image quality.

Claims (1)

[Claims] 1. A sublimation type thermal transfer recording medium, which has an ink layer laminated on a substrate, in which a dye supply layer and a dye transfer contribution layer each having a sublimable dye dispersed in an organic binder are laminated in order from the substrate side. , the organic binder of the dye transfer contributing layer is 60 to 60%.
A sublimation thermal transfer recording characterized in that the dye supplying layer is made of a resin having a glass transition temperature (Tg) of 150°C, and the organic binder of the dye supply layer is a resin having a glass transition temperature (Tg) of 0 to 60°C. Medium.