JPH02238992A - Thermal transfer recording medium - Google Patents

Abstract

PURPOSE:To realize a gradation expression superior in reproducibility at the time of thermal transfer by a method wherein a hot melt ink applied on a substrate has fine cracks in a disordered form in its coated area and a specific coating thickness. CONSTITUTION:In this thermal transfer recording medium, a hot melt ink 101 or 111 applied on a substrate 102 or 112 has fine cracks 113 in a disordered form in its coated area. In addition, the hot melt ink 101 or 111 is applied with a thickness less than 10mum. In this construction, a gradation expression superior in reproducibility can be performed at the time of thermal transfer esp. in the range from a medium density to a high density.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a thermal transfer recording medium used in a thermal melt transfer printer. [Prior Art] Conventional thermal transfer recording media are semi-etched to form a uniform layer of heat-melting ink. (Problem to be Solved by the Invention) However, the above-mentioned conventional technology has a problem in that during thermal transfer, water jumps are likely to occur when moving from a medium-lacquered area to a high-density area.Therefore, the present invention solves this problem. The purpose is to provide a thermal transfer recording medium that can express gradations with excellent reproducibility during thermal transfer. [Means for Solving the Problems] Thermal transfer recording medium of the present invention is characterized in that the heat-melting ink coated on the base material has minute cracks scattered randomly in the coated area, and preferably the coating thickness of the ink is 10 (μm or less). [Function] According to the above structure of the present invention, there is an effect that a thermal transfer recording medium can be provided which can express gradation with excellent reproducibility during thermal transfer, especially in a medium density area to a high density area. Example] The present invention will be explained in detail below using Examples and Comparative Examples. Examples are shown in Fig. 1. Fig. 1 shows a graph of the heat-melting ink (101) coated on a base material (102). This is a summary.Also, 1
113 is an enlarged view of the main part of 101. 111 shown with diagonal lines represents the surface of the heat-melting ink, 113 represents the crack part. 112 is an enlarged view of the main part of the base material 102, which is made of polyethylene terephthalate. , aromatic polyamide, aliphatic polyamide, polyimide, polyether sulfone, condenser paper, etc. There is no problem as long as it can be applied to ordinary thermal transfer substrates.The coating thickness of this ink is not particularly limited, but it is preferably 10 [μm] or less.Next, as a comparative example, Figure 2 shows an outline of the coating surface of a conventional heat-melting ink.
201 is a heat-melting ink, and 202 is a base material. Also, 2
11 is an enlarged view of the main parts of 201 and 212 is an enlarged view of the main parts of 202. In Figure 2, the intentionally created crack shown at 113 is not observed. Table 1 shows the compositions of the hot-melt inks used in Examples and Comparative Examples of the present invention. Of course, since the present invention relates to the structure of a thermal transfer recording medium, it is not limited to the compositions shown in Table 1. Further, the ink can be applied using a conventional hot-melt ink coating technique such as a hot-melt method or a solvent method. Table 1, Figure 3 (301) is the gradation characteristic of the present invention, and (302) is the gradation characteristic of the prior art. The vertical axis represents the reflection OD normalized to the maximum value of 1.0, and the horizontal axis represents the transfer energy (30
1) has a transfer energy of 25 to 29 compared to (302).
[It can be seen that the concentration changes extremely gradually in the mJ/mml region, that is, from the medium concentration region to the high concentration region. Figure 4 is a model showing a state in which conventional heat-melting ink (404) is melted by the heat generated by the heating element (407) of the thermal head (406). The ink melting area is the area surrounded by ABCD and EFGH. Further, (403) is the base material, and (405) is the ink that is transferred as heat is generated. Now, if the transfer energy is increased, AB, EF} will gradually become longer and BE will become shorter. Therefore, the adhesive force (401) between the non-melting ink BEDG and the base material becomes weaker as the transfer energy increases. On the other hand, the force (402) that acts as resistance when ABCD and EFGH come out of the thermal transfer recording medium is hardly affected by the transfer energy. Therefore, when the transfer energy increases to a certain extent, (402) becomes stronger than (401). In this case, the ink BEDG, which should originally remain on the base material, is also transferred at the same time, resulting in a transfer degree that greatly exceeds the originally intended transfer degree. FIG. 5 shows an example of the present invention that shows the effect of cracks in the ink layer, and the heat-melting ink (504) mixed with cracks (508) is affected by the heat generated by the heating element (507) of the thermal head (508). This model shows the molten state. The ink melted area is an area surrounded by A'B'C'D' and E'F'G'H'. Further, (503) is the base material, and (505) is the ink that is transferred as heat is generated. Now, if the crack part of the hot-melt ink exists near B'D'E'G' as in the present invention, the force (602) will be smaller than the force (402). On the other hand, since force (501) is equivalent to force (401), when force (501) < force (502), B'E' becomes shorter than BE. As a result, it is possible to achieve a sufficient transfer density before B'E'D'G' is transferred unintentionally, and the density jump from the medium density area to the high density area is small, resulting in thermal transfer with good reproducibility. A recording medium is obtained. (Effect of Ta Akira) As described above, according to the present invention, the thermal transfer recording is characterized in that the heat-melting ink coated on Akimurakami has minute cracks in a random manner in the coated area. The medium, preferably a thermal transfer recording medium characterized in that the coating thickness of the heat-melting ink is 10 [μm] or less, has gradations with excellent reproducibility during thermal transfer, especially in medium to high density areas. 212 of 201 is an enlarged view of the main part of 202. Figure 3 is a diagram showing the gradation stability of the present invention and the prior art. Figure 4 (a) (b)
The figure below shows an overview of transfer using conventional thermal transfer recording media. FIGS. 5(a), 5(b), and 5(c) are diagrams showing a transfer outline of the thermal transfer recording medium of the present invention. Applicant Seiko Epson Co., Ltd. Agent Patent Attorney Kisaburo Suzuki and one other person

[Brief explanation of drawings]

Figures (a) and (b) are diagrams showing examples of the present invention, in which the hot melt ink (101) coated on the base material (102)
) schematic diagram. Also, 111 and 113 are enlarged views of the door of 101, showing the surface part of the heat-melting ink and the crack part, respectively. FIGS. 2(a) and 2(b) are diagrams showing comparative examples, and are schematic diagrams of coating surfaces of conventional heat-melting inks. 201 is a heat-melting resin, 202 is a base material, and 211 is a heat-melting resin. /itt ts (a) Figure 4

Claims (2)

[Claims] (1) A thermal transfer recording medium characterized in that the heat-melting ink coated on the base material has minute cracks in a random manner in the coated area. (2) The thermal transfer recording medium according to claim 1, wherein the coating thickness of the heat-melting ink is 10 [μm] or less.