JPS62211194A - Thermal sublimation color recording method - Google Patents

Abstract

PURPOSE:To obtain recording generating no re-transfer and having good color reproducibility, by a method wherein dyes are successively transfered from one having higher sublimation temp. when the sublimable dyes of an ink sheet are thermally transferred to an image receiving material and the heat energy applied to a dye to be transferred later is lowered corresponding to the sublimation temp. of said dye. CONSTITUTION:The relation between the sublimation temps. of a sublimable dye A having sublimation temp. T1, a sublimable dye B having sublimation temp. T2 and a sublimable dye C having sublimation temp. T3 is set to T1>T2>T3. In recording, heat energy W1 sufficient for transfer is applied to the sublimable dye A at first to perform recording and, next, heat energy W2 is applied to the sublimable dye B to perform recording and, at last, heat energy W3 is applied to the sublimable dye C to perform recording. In this case, the relation between heat energies W1, W2, W3 is set to W1>W2>W3. By successively transferring the dyes in order from the one having higher sublimation temp., the re-transfer of the dye transferred in advance to a base film 13 is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a thermal sublimation color recording method used for hard copies and the like.

[Prior art] The basic principle of the thermal sublimation recording method will be explained with reference to FIG.

In the figure, 31 is a thermal head, 32 is a platen roller,
33 is a sheet-like base material (hereinafter referred to as base film) for supporting a heat-sublimable dye; 34 is a heat-sublimable dye coated on the base film together with a suitable binder;
5 is an image receiving paper which is an image receptor. A base film 33 and an image receiving paper 35 are stacked so that the surface coated with sublimation dye faces the image receiving paper 35, and a thermal head 31 is installed on the back side of the base film 33 (the surface not coated with dye);
It is pressed with a platen roller 32 installed on the back side of the image receiving paper 35 (not in contact with the dye). Next, when power is applied to the heating element of the thermal head 31 according to the recording signal, the thermal energy generated from the heating element is transferred to the base film 33.
is transmitted to the sublimable dye 34 via the sublimable dye 34. The heated sublimable dye 34 sublimates and immediately faces and contacts (
The surface layer of the X-shaped image receptor 135 is stained to form a visible stain. The feature of the thermal sublimation recording method is that by controlling the heat generation M of the thermal head 31 i, 11, the sublimation fd of the dye can be changed.
Cold I! It is possible to record in 2i format. Also,
When recording in color, use an ink sheet with the three colors of yellow (Y), mapinta (M), and cyan (C) applied separately to each screen, as shown in Figure 2. ,
It is sufficient to simply transfer each color of dye to the image receiving paper 25 side in order. In this way, the thermal sublimation recording method is a recording method that can easily perform full-color recording with continuous gradation like silver-tone photography.

[Problems to be Solved by the Invention] Conventionally, when color recording is performed using a thermal sublimation recording method, the order in which dyes are transferred to image-receiving paper is Y, M, C, or C, C, in accordance with the process printing method. I got 11 in the order of M and Y. However, when actually performing color recording, the sublimation temperature differs depending on the type of dye, so the following problems conventionally occur. That is, if the sublimation temperature of the first color dye is lower than the sublimation temperature of the second color dye, the thermal energy applied to avoid sublimation of the second color and transfer it to the receiver paper has already caused the dye to be transferred to the receiver paper. The dye of the first color that has been applied will sublime again and be re-transferred to the base film. Therefore, the recording density of the first color becomes lower than the predetermined one shift. When transferring the third color, if the sublimation temperature of the dye of the first and second color is lower than that of the third color, the same problem occurs.The thermal sublimation recording method is a thermal melt recording method. The thermal energy required for transfer is 4~
It is about 5 times larger. Nevertheless, retransferring the transferred dye to the base film is not only a technical problem, but also a big problem from the standpoint of color reproduction.

The present invention has been made in view of the above-mentioned circumstances, and aims to provide a thermal sublimation color recording method that does not cause retransfer and has good color reproduction.

[Means and effects for solving the problem] In Fig. 1, 11 is a thermal head, 12 is a platen roller, 13 is a base film, and 14 is a sublimation temperature T1.
15 is a coating layer of sublimable dye A having a sublimation temperature T2, 16 is a coating layer of sublimable dye C having a sublimation temperature T3, and 17 is an image receiving paper serving as an image receptor. However, the relationship between the sublimation temperatures of each dye 1 is TI>T2>73. During recording, first, thermal energy W1 sufficient for transfer is applied to sublimable dye 1△ for recording, then thermal energy W2 is applied to sublimable dye B for recording, and finally, Thermal energy W3 is applied to the sublimable dye C for recording. However, it is assumed that Wl>W2>W3. In this way, by transferring the dye in order from the one with the highest sublimation temperature, it is possible to prevent the previously transferred dye from being retransferred to the base film 13.

[Example of fruit] The sublimable dyes shown by the following three color index names are mixed in a methylcellulose binder at an ω ratio of 5% to produce blue dye, yellow dye, and red dye. The base film thickness is 10 μm.
An experimental ink sheet was prepared by coating a5Qy'm2 on a polyester film using a roll coater.

Blue bundle FI Disp Blue 5G (R￥X
4 tf 210℃) Yellow dye Disp Yellow
ow 8 (sublimation temperature 200℃) red dye Disp
Red 55 (sublimation temperature 180℃) However, the stomach! 1
! Transfer the dye in order of temperature, starting with the blue dye (corresponding to A in Figure 1), then the yellow dye (corresponding to 8 in Figure 1), and finally the red dye (corresponding to 8 in Figure 1). (corresponding to C in FIG. 1). For the transfer head, a thermal transfer printer equipped with a thick film type thermal head with a heating resistor element density of 12 dOt/11+11 was used. As the image receiving paper 17, polypropylene synthetic paper whose transfer surface was coated with polyester resin was used. As shown in FIG.
2 and energize the thermal head 11,
A transcription record was made. First, the blue dye was transferred to the receiving paper 17. The transfer energy required for the recording a of paper 17 to reach saturation density and for the ink sheet to become almost transparent was 1/J6 mJ/dot. Next, the image-receiving paper 17 was run in the reverse direction and returned to its original position, and the yellow dye portion was superimposed thereon to transfer the yellow dye. At this time, the transfer energy required for most of the yellow dye to sublime and for the ink sheet to become almost transparent was approximately 5°2 mJ, /do°C.
However, there was only slight visual evidence that the previously transferred blue dye had been retransferred to the ink sheet. Furthermore, the receiver paper was run in the reverse direction once again to return to its original position, and the red dye area was overlapped, and the red dye was transferred thereon. At this time, the transfer energy required for most of the red dye to sublimate and for the ink sheet to become almost transparent was approximately 3.8 mJ/'dot, and one layer of blue dye and one yellow dye were applied to the ink sheet. Almost no evidence of retransfer of [was observed with the naked eye. Thus, it was observed that almost no retransfer from the receiver paper to the ink sheet occurred.

[Effect of the invention] This invention has the following effects.

(1) Since the dye transferred to the image receptor is not re-transferred to the base film, the recording zero degree does not decrease.

(2) Higher saturation density than when there is retransfer is 1! ?
The color reproduction range is widened (the saturation is increased).

(3) Since there is no reduction in saturation or change in hue due to retransfer, image processing for reproducing a predetermined image becomes easy.

[Brief explanation of drawings]

FIG. 1 is a diagram for explaining the principle and embodiments of the present invention, and FIGS. 2 and 3 are diagrams for explaining a conventional example. 11... Thermal head, 12... Platen roller, 13... Base film, 14... Coating layer for sublimable dye (sublimation temperature TI) 15
...Coating layer of sublimable dye B (sublimation temperature T2>16...
・Coating layer of sublimable dye C (sublimation temperature T3) 17...image receiving paper (image receptor)

Claims (1)

[Claims] In the thermal sublimation color recording method, an ink sheet is formed by coating a sheet-like carrier with a plurality of sublimable dyes of different colors, and the sublimable dyes on the ink sheet are transferred onto an image receptor using heat. A thermal sublimation color recording method characterized by sequentially transferring dyes starting from the highest temperature, and transferring heat energy given to dyes to be transferred later in such a manner as to decrease in accordance with the sublimation temperature of the dye.