JPS60125696A - Color thermal transfer recording method - Google Patents

Abstract

PURPOSE:To obtain color thermal transfer recorded pictures having good quality by preventing the occurrence of bleeding and deficiency of record by a method in which at the time of thermal transfer recording using a transfer film of plural colors, recording is made in the order of higher transfer temperatures. CONSTITUTION:A recording paper 1 and transfer films of yellow (Y), magneta (M), and cyanin (C) 2-1-2-3 are run at the same speeds. Y-color picture is first formed by a thermal head 5-1, M-color picture is then formed by the head 5-2, and C-color picture is lastly formed by the head 5-3. During the period, the transfer temperatures of each film are regulated in such a way that the transfer temperature of Y-color transfer film 2-1 > that of M-color transfer film 2-2 > that of C-color transfer film 2-3. Also, heating pulse width to be applied to each head is controlled, and greater applied energy is set up, the higher the transfer temperature. The transferring order of each color is determined by making allowance for the manifesting probability and fading tendence of colors, and the transfer temperature is regulated.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Description of the field to which the invention pertains The present invention is directed to a color thermal transfer recording method that is applied to recording devices such as facsimiles and printers, in which recorded images with less color bleeding and color unevenness can be obtained. It is related to the method used.

(2) Description of conventional technology Figure 1 shows an example of the configuration of a general color thermal transfer recording method. In the figure, 1 is recording paper, and 2-1 to 2-3 are the three primary colors for printing. yellow (2), magenta (goods), cyan (
Transfer film of color C), 3-1 to 3-3 are transfer film rolls, 4-1 to 4-3 are winding rollers, 5-
1 to 5-3 are thermal heads, and 6-1 to 6-3 are platen rollers.

In the figure, recording paper 1 and transfer films 2-1 to 2-
3 runs at the same speed, first a Y color image is formed by the thermal head 5-1, then a M color image is formed by the thermal head 5-2, and finally a C color image is formed, and any color image is formed. Figure 2 is a diagram showing the basic principle of thermal transfer recording, in which 7 is a base film, 8 is a colored material layer, 5-1α is a heating element, and Y by the thermal head 5-1 in Figure 1 is FIG. 3 is an enlarged view of a color forming section. The same applies to other colors. Heating element 5-
16 are arranged in large numbers in a direction perpendicular to the paper surface of FIG. 2, forming a play corresponding to one line. When the heating element 5-1a is heated in accordance with the image signal, the colored material layer 8 in the vicinity melts or sublimates, and the colored material is transferred onto the recording paper 1, thereby obtaining a desired image. The coloring substance layer 8 is a heat-melting ink layer or a layer containing a sublimable dye, and is Y in the transfer film 2-1, M in the transfer film 2-2, and C in the transfer film 2-3.

Conventionally, in the color thermal transfer recording method as shown in FIG. Each of the thermal heads 5-1 to 5-3 was driven using preferably the same applied energy. However, in this case, as shown in FIG. 3 as an enlarged view of the M color forming section in FIG. At this time, since the transferred image 9 is reheated, a portion of the transferred image 9 is transferred (reversely transferred) to the transfer film 2-2 side, resulting in a reversely transferred image 11 and a recording gap 12, which is extremely likely to impair the image quality. There were drawbacks.

(3) Purpose of the Invention In order to eliminate these drawbacks, the present invention prevents reverse transfer by providing a difference in transfer temperature for each color. Explanation of the structure and operation of FIG. 4 is a diagram explaining the principle of the present invention based on an embodiment,
13 is a previously formed transfer image, and 14 is a subsequently formed transfer image. In the figure, the transfer temperature of the transferred image 13 is θ
When the transfer temperature of the transferred image 14 is 02, the relationship is set as θ2×θl. In other words, since the color to be newly thermally transferred has a lower transfer temperature than the previously formed transfer image 13, it can be thermally transferred with less applied energy than when the transfer image 13 was formed. Therefore, the temperature at which the previously formed transfer (813) is reheated by the thermal head 5-2 is lower than in the case of FIG. The probability of this occurring can be made extremely low.

In order to apply the above principle to the configuration shown in FIG. If the transfer temperature of the transfer film 2-3 is 02s, θ■×θ22<θ
21, and the thermal head 5-1
The energy applied to the transfer films 2-1 to 5-3 may be set to be larger as the transfer temperature is higher, depending on the transfer temperatures θ21 to θ23 of the transfer films 2-1 to 2-3.

In order to adjust the transfer temperature of each transfer film 2-1 to 2-3, in the case of heat-melting ink, for example, the content of carnauba wax may be adjusted, and in the case of sublimable dye, the content of carnauba wax may be adjusted to the desired level. A dye having a temperature may be used. Furthermore, in order to control the energy applied to the thermal heads 5-1 to 5-3, the pulse width of the heating pulse applied to the thermal heads 5-1 to 5-3 may be controlled.

By the way, in FIG. 1, it has been explained that Y, M, and C are thermally transferred in the order, but the present invention is not limited to this, and the point is that the thermal transfer is performed so that they are stacked from the bottom in the order of the highest transfer temperature.

For example, the lower the probability of appearance of a color, the higher the transfer temperature may be, and the color may be thermally transferred recorded before the other colors.

Data on the statistical content of each color Y, M, and C in general color manuscripts has not yet been investigated, but let us assume C, Y, and M in descending order of probability of appearance.

In this case, as shown in FIG. 5, by thermally transferring M, Y, and C in the order of M, Y, and C, and setting the transfer temperature in descending order of M, Y, and C, image quality deterioration due to reverse transfer can be prevented, and at the same time, The higher the probability of appearance of a color, the lower the applied energy, which has the advantage of reducing the energy required for overall recording.

In addition, especially in the case of transfer films using sublimable dyes,
The transfer temperature may be set higher for colors that fade more easily. In the case of sublimable dyes, depending on temperature and light after recording,
The recorded image fades, albeit gradually, and the rate of fading varies depending on the color, and the lower the transfer temperature, the faster the rate of fading tends to be. Therefore, by setting the transfer temperature higher for colors that are more likely to fade and performing thermal transfer first with higher applied energy, it is possible to prevent image quality deterioration due to reverse transfer and at the same time improve the fading resistance of the recorded image as a whole. . The fading speed differs depending on the coloring material, but if we assume M, Y, and C in descending order of fading speed, as shown in Figure 5, M, Y,
, C, the recording order, the order of the highest transfer temperature, and the order of the highest applied energy may be set.

FIG. 6 shows another embodiment of the present invention, in which 15 indicates Y, M,
A transfer film in which each color of C is sequentially applied in a striped manner as shown in Figure (b), 16 is a recording paper 1 and a transfer film 15
This is a peeling roller for peeling off. This example is shown in the figure (,
), the running speed of the transfer film 15 is set as τ/(% is a positive constant) with respect to the running speed τ of the recording paper. Furthermore, when the length of the original is L and the length of the area coated with one color on the transfer film is J, then n*L/l, where l is the thermal head 5-1 and 5-2 of the transfer film.
Or, it roughly matches the running path length between 5-2 and 5-3.

As in this method, when the running speed of the transfer film 15 is generally slower than the running speed of the recording paper, the probability of reverse transfer occurring is higher due to the misalignment between the recording paper 1 and the transfer film 15. . Therefore, in FIG. 6, reverse transfer can be prevented by increasing the transfer temperature and applied energy for colors that are recorded first, thereby preventing deterioration in image quality.

(5) Description of effects As explained above, according to the present invention, by a simple method,
Since it is possible to prevent image quality deterioration such as bleeding and recording omissions due to reverse transfer, there is an advantage that color thermal transfer recorded images of good image quality can be obtained.

For convenience of explanation, yellow (2), magenta M.

Although the recording method using cyan (C) has been described, the present invention is not limited to this. For example, Y.

In addition to M and C, black (BK) may be added.

Furthermore, it may be a combination of arbitrary colors.

[Brief explanation of the drawing]

Figure 1 is a block diagram of a general color thermal transfer recording method;
The figure is an explanatory diagram of the principle of thermal transfer recording, Fig. 3 is an explanatory diagram of image quality deterioration, Fig. 4 is an explanatory diagram of the principle of an embodiment of the present invention, and Figs. 5 and 6 are illustrations of different embodiments of the present invention. It is an explanatory diagram. In the figure, 1 is recording paper, 2-1 to 2-3 are transfer films,
3-1 to 3-3 are transfer film rolls, 4-1 to 4-3 are take-up rollers, 5-1 to 5-3 are thermal heads, 5-1α and 5-2α are heating elements, 6-1 to 6
-3 is a platen roller, 7 is a base film, 8 is a colored material layer, 9°13 is a previously formed transfer image, 10.14
11 is a reverse transfer image, 12 is a recording gap, 15 is a transfer film, and 16 is a peeling roller. Patent applicant Hiroshi Mori, patent attorney representing Nippon Telegraph and Telephone Public Corporation

Claims (1)

[Claims] 1) A color thermal transfer recording method in which each of a plurality of colors is sequentially thermally transferred onto recording paper using a thermal head,
In addition to using transfer films with different transfer temperatures for each color,
A color thermal transfer recording method characterized by thermal transfer recording of a color with a higher transfer temperature before a color with a lower transfer temperature. 2) The color thermal transfer recording method according to claim 1, wherein the heating pulse width of the thermal head is set to a longer pulse width as the color is recorded first. 3) The color thermal transfer recording method according to claim 1, characterized in that the running speed of the transfer film is 1/fL of the running speed of the recording paper. 4) The color thermal transfer recording method according to claim 1, characterized in that the higher the probability of appearance of a color, the lower the transfer temperature. 5) The color thermal transfer recording method as set forth in claim 1, in which the color that is more likely to fade after recording is set at a higher transfer temperature.