JPS61249778A - Thermal transfer color printing system - Google Patents

Abstract

PURPOSE:To prevent dot shift and to perform accurate color reproduction, by printing a mark on printing paper immediately before first color printing and returning the printing paper after the completion of printing to detect the mark and performing second and succeeding color printings on the basis of said mark. CONSTITUTION:A photoelectric detector 11 for detecting a mark is provided on the cover plate 4 of a thermal printing head 1 in close vicinity to a heat generator row 3 and the output signal of the photoelectric detector 11 is taken in CPU10. Data to be printed is outputted to a decoder driver 12 from CPU10 and each heat generator generates heat by the signal from the decoder driver 12 to perform printing. When the presence of a printing order is judged, the heat generator row 3 is operated to print a mark 13 on printing paper 7. Said mark 13 is printed slightly on this side from an information printing region. Succeedingly, it is judged whether the printing paper 7 moves by a predetermined distance (d). When it is assumed that the printing paper 7 moved by the distance (d), the printing of information is successively applied to the printing region 14 of the printing paper 7 by yellow corresponding to a color number 1.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application This invention relates to a thermal transfer color printing system, and particularly to a thermal transfer color printing system that reduces color shift.

(b) Conventional technology When color printing is performed using a line-type thermal print head, generally Y (yellow), M (magenta),
A thermal transfer paper in which C (cyan) inks are sequentially arranged is used, and each ink is printed one on top of the other to reproduce a predetermined color.

In this case, after printing the first color (Y), the motor for feeding the printing paper is reversed, the printing paper is rewound a certain amount, the beginning of the paper is searched, and the next second color (M) is printed. and overlapping printing is performed. (C) Problems to be Solved by the Invention In the conventional printing method described above, in practice, a slight error occurs between the rotation amount of the motor and the feeding amount of the printing paper (transfer paper), resulting in overlapping. Even if it is intended to be printed, dots may be misaligned, making it difficult to reproduce colors accurately.

In view of the above, an object of the present invention is to provide a thermal transfer color printing method that can prevent dot misalignment and achieve accurate color reproduction.

(d) Means and operation for solving the problems In the thermal transfer color printing method of the present invention, before printing the first color, a mark is printed on the printing paper using a thermal print head, and the first color printing After finishing, the printing paper is returned, the printed mark is detected, and the second and subsequent colors are printed based on this mark.

In this thermal transfer color printing method, a mark is printed before printing the first color, and the next second and third colors are printed based on this mark, so the mark point and the printing area are placed close together. can do. Therefore, if the marks are used for alignment, the dot misalignment caused by overprinting will be extremely small.

(e) Examples The present invention will be explained in more detail with reference to Examples below.

FIG. 1 is a schematic diagram of a thermal transfer color printer showing an embodiment of the present invention. In the figure, a thermal print head 1 includes a heating element row 3 formed on a substrate 2. As shown in FIG. Note that 4 is a cover plate. The heating element row 3 is
A plurality of dots (heating elements) are arranged in a line, and a platen roller 5 is provided facing the linear row of heating elements 3. Furthermore, color thermal transfer paper 6 and printing paper 7 are interposed between the heating element array 3 and the platen roller 5.

The feeding of the color thermal transfer paper 6 is controlled by a thermal transfer paper control section 8, and the forward and reverse feeding of the printing paper 7 is controlled by a printing paper control section 9. There is. These thermal transfer paper control section 8 and printing paper control section 9 are operated by a CPU (microcomputer).
It operates according to commands from 10.

Further, a photoelectric detector 11 for mark detection is provided on the cover plate 4 of the thermal print head 1 in the vicinity of the heating element row 3, and the output signal of this photoelectric detector 11 is transmitted to the CPU10.
It is now being incorporated into the

Data to be printed is output from the CPU I O to the decoder driver 12, and a selected heating element in the heating element array 3 generates heat in response to a signal from the decoder driver 12, thereby performing a printing operation.

Next, the operation of the printer of the above embodiment will be explained with reference to the flowchart shown in FIG.

When the operation starts, first, the counter C is set to the initial state, that is, 0 (step 5TI). This counter C is C
It is built in P U 1 'O and is provided to count the number of printed colors. Here, the printing color numbers are 1 for yellow, 2 for magenta, and 3 for cyan.

After setting the counter C to 0, it is determined whether or not there is a printing command (step 5T2). If it is determined that there is a printing command, the heating element row 3 of the thermal print head 1 is then activated.
Print mark 13 on printing paper 7 (step 5T3)
. For example, as shown in FIG. 3, if the mark 13 is printed on the printing paper 7 in the direction of the arrow, it will be printed slightly before the information printing area 14.

Subsequently, it is determined whether the printing paper 7 has moved a predetermined distance d (step 5T4). This distance d is the mark 13
This is the distance from to the printing area 14. If the printing paper 7 moves a distance d, the counter C is incremented by 1 and C=1.
Then, in step 5T5), information is sequentially printed in yellow corresponding to the color number 1 on the printing area 14 of the printing paper 7 (step 5T6). Then, it is determined whether printing has ended or not (step 5T7), and the processes of steps ST6 and ST7 are repeated until printing of the printing area 14 is completed. When printing is completed and the determination in step ST7 is YES, it is then determined whether the content of the counter C is 3 (step 5T8), and if it is not 3, step ST
At step 9, the process moves to rewinding the printing paper 7, and when the rewinding is completed (step 5TIO), forward feeding of the printing paper 7 is restarted (step 5T11), and it is determined whether or not the mark 13 has been detected. (Step 5T12).

When the mark 13 is detected by the photoelectric detector 11, the determination in step 5T12 becomes YES, and the process returns to step ST4. In step ST4, it is then determined whether or not the printing paper 7 has been fed by the distance d. If this determination is YES, in the next step ST5, the counter C is set to +IL(C
= 2), and this time information is printed on the printing paper 7 in magenta corresponding to color 1 number 2 (step 5T6),
The information is printed continuously until the color printing is completed. When the magenta information printing is completed, the determination in step ST7 becomes YES, and then, as in the previous case of yellow printing, in step ST8 C=
After determining whether it is 3 or not, the printing paper 7 is rewound (step ST9.5TIO).

When the rewinding is completed, the feeding of the printing paper 7 is restarted, and it is determined whether or not the mark 13 has arrived (step 5T12). When the mark 13 is detected, the process returns to step ST4 again, and when the printing paper 7 is further fed by a distance d, the counter C is incremented by 1 and C=3 (step 5T5), and the cyan corresponding to the color number 3 is added. The information is printed (step 5T6). When printing is completed, it is determined whether C=3 (step 5T8), but since this determination is YES, the operation is ended.

In the above embodiment, the mark 13 has the shape of two points, but the shape of the mark is not limited to this, and may be linear, frame-shaped, etc., for example.

(f) Effects of the Invention According to this invention, by detecting the mark near the heating element, it is possible to cue each color immediately before printing, thereby minimizing dot misalignment and achieving clear color printing. be able to. Therefore, this invention is suitable for use in halftone full color printing.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of a thermal printer showing an embodiment of the present invention, Fig. 2 is a flow diagram for explaining the operation of the printer, and Fig. 3 is a mark printed by the printer. It is a figure showing a paper. 1: Thermal print head, 3: Heating element row, 5 Nibraten, 6: Thermal transfer paper, 7: Print paper, 13: Mark. “9, b Jin:

Claims (1)

[Claims] (1) In a thermal transfer color printing method that uses thermal transfer paper on which a plurality of transfer colors are arranged in sequence and prints the plurality of transfer colors in an overlapping manner using a thermal print head, immediately before printing the first color, a thermal transfer paper is applied to the print paper. A print head prints a mark, and after the printing of the first color is completed, the printing paper is returned to detect the mark, and the second and subsequent colors are printed based on this mark. Thermal transfer color printing method.