JPH0911641A - Color printing method of thermal color printer - Google Patents

Abstract

PURPOSE: To shorten printing time, to eliminate fixing operation performed at each one-color printing and to simplify the structure of an apparatus by performing color printing performed over three times heretofore at once. CONSTITUTION: In a color printing method of a thermal color printer, color thermal paper capable of changing a color developed by the temp. change of the heating elements of a thermal head 15 controllable in heating temp. and density is used and three adjacent dots are printed so as to obtain necessary densities of yellow, magenta and cyan and a desired color is developed by the combination of these three colors. Further, only the color having the highest density among the three primary colors of yellow, magenta and cyan constituting the developed color is printed in its density.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color printing method for a thermal color printer, and more particularly to a color printing method for a thermal color printer for performing multicolor printing on thermal paper.

[0002]

2. Description of the Related Art FIG. 5 shows, for example, JP-A-5-185627.
It is a block diagram which shows an example of the conventional thermal color printer as shown in the publication. Referring to FIG. 5, the cam 29 is rotated by the motor 32, and the thermal paper 27 is pressed against the feed roller 23 by the arm 28. The clamp arm 34 is pushed up by the arm 30 at the thermal paper clamp position. Next, the feed roller 23 is rotated by the motor 22 and the thermal paper 21 is conveyed until it is sandwiched between the platen drum 35 and the clamp arm 34, and then the motor 32 is rotated in the reverse direction to release the arm 28 and the arm 30. The platen drum 35 is rotated in the direction of arrow A by the rotation of the motor 22, and the thermal paper 21 is held by the clamp arm 34 while the leading end of the platen drum 35 is held.
Is wrapped around. When the clamp arm 34 passes under the thermal head 36, the motor 32 rotates and the cam 31 presses the thermal head 36 against the thermal paper 21,
Yellow printing starts. At the same time, the yellow fixing lamp 19 is turned on, and fixing is started from the position where printing is completed. When the yellow printing is completed, the thermal head 36
Is released from the platen drum 35. When the clamp arm 34 passes under the thermal head 36 again, the thermal head 36 is pressed again to start printing magenta. At the same time, the yellow fixing lamp is turned off, the magenta fixing lamp is turned on, and magenta fixing is performed. After printing cyan, the clamp arm 34 is released by the rotation of the motor 32, and the thermal paper 21 is separated from the platen drum 35 by rotating the motor 22 in this state. While being guided by 26, the sheet is conveyed to the discharge port by the feed roller 23, and the operation is completed.

FIG. 6 is a diagram showing the color-developing characteristics of color thermal paper used in this conventional thermal color printer. In FIG. 6, the horizontal axis represents the thermal energy generated by the heating elements of the thermal head, and the vertical axis represents the color density of color thermal paper. As shown in FIG. 6, this color thermal paper has the lowest heat energy for developing the yellow (Y) heat sensitive layer and the highest heat energy for developing the cyan (C) heat sensitive layer.

[0004]

In this conventional printing method, printing of three colors is performed in three steps. Therefore, after winding the thermal paper around the platen drum, the platen drum must be rotated three times or more. It takes time to print. Further, since printing is performed three times, the data memory section in the control circuit is provided for three times, and the fixing ultraviolet lamp is provided, so that the apparatus becomes large and expensive.

An object of the present invention is to shorten the printing time by performing color printing, which is conventionally performed in three times, in one time, and to eliminate the fixing operation performed for each color printing. It is an object of the present invention to provide a color printing method for a thermal color printer which has a simple structure and can be manufactured at low cost.

[0006]

A color printing method for a thermal color printer according to the present invention uses a color thermal paper capable of changing a color and a density to be developed by a temperature change of a heating element of a thermal head capable of controlling a heating temperature. The three adjacent dots print the required densities of yellow, magenta, and cyan, respectively, and a desired color is expressed by a combination of these three colors.

Further, the color printing method of the thermal color printer according to the present invention uses a color thermal paper which can change the color and density of the color produced by the temperature change of the heating element of the thermal head capable of controlling the heat generation temperature. It is characterized in that only the darkest color of the three primary colors of yellow, magenta, and cyan that compose the color expressed by one of the bodies is printed at that density.

[0008]

Next, the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing the construction of an embodiment of a thermal color printer used in the present invention. Referring to FIG. 1, when print data is sent from the higher-level device 1 to the control circuit 2, the control circuit 2 converts the print data into a signal for driving the thermal head 15 based on a color printing method described later. To do. When this conversion work is completed, the control circuit 2 drives the carry motor 3 to feed the thermal paper 7 out of the paper box 6 via the belt 4 and the feeding roller 5. The fed thermal paper 7 passes through the paper detection sensor 12 by the feed roller 10 and the idler roller 11 which are driven from the conveyance motor 3 via the belt 8 and the belt 9, and is conveyed to a position of several steps to be temporarily stopped. When the carry motor 3 stops, the solenoid 13
Is released, and the thermal head 15 is pressed against the thermal paper 7 on the platen 16 by the pressing force of the spring 14.

A current is applied to the pressed thermal head 15 by the control circuit 2 based on a color printing method described later, so that the thermal paper 7 is colored. The control circuit 2 finishes heating for a certain period of time required for the thermal paper 7 to develop color,
The application of the current to the thermal head 15 is completed. When the printing of one line is completed, the control circuit 2 drives the carry motor 3 to rotate the platen 16 via the belt 8 and carry the thermal paper 7 by one line feed. When the conveyance is completed, the control circuit 2 applies a current again based on the converted print data to print the next line. By repeating the above operation, all the print data is printed, and the printing operation is completed.

When the printing operation is completed, the control circuit 2 drives the carry motor 3 to rotate the platen 16 via the belt 8 and carry the thermal paper 7 until the rear end of the thermal paper 7 passes the paper detection sensor 12. . At this time, the leading edge of the paper has already come out of the discharge port through the paper guides 17 and 18. When the conveyance is completed, the control circuit 2 applies a current to the solenoid 13 to pull up the thermal head 15. This completes the discharging operation of the thermal paper 7.

FIG. 2 is a diagram showing the coloring characteristics of the thermal paper used in the present invention. In FIG. 2, the horizontal axis represents the heat energy generated by the heating element of the thermal head, and the vertical axis represents the color density of the thermal paper. As shown in FIG. 2, this thermal paper has the lowest heat energy required for developing cyan (C) and the highest heat energy required for developing yellow (Y). The color development characteristic of the thermal paper used in the present invention is not limited to the one shown in FIG. 2 and may be the one shown in FIG. 6, and it may be one of yellow (Y), magenta (M) and cyan (C). It suffices that the coloring characteristics are separated by the applied thermal energy.

FIG. 3 is a diagram for explaining a color printing method according to the first embodiment of the present invention. Referring to FIG. 3, in the color printing method of this embodiment, one color is represented by 3 × 1 dots, which constitutes one pixel. This one pixel expresses a color by developing each color of yellow (Y), magenta (M) and cyan (C) with an appropriate density. Adjacent 3 dots of the thermal head 15 are yellow (Y).
It is divided into color forming dots, magenta (M) color forming dots, and cyan (C) color forming dots. The heat generation of the thermal head 15 is controlled by the control circuit 2 so that the temperature corresponds to the coloring density of each color.

FIG. 4 is a diagram for explaining a color printing method according to the second embodiment of the present invention. In the above-described first embodiment, the colors of yellow (Y), magenta (M) and cyan (C) are arranged side by side to develop colors, but in the second embodiment, as shown in FIG. , Yellow (Y), magenta (M), and cyan (C) are arranged as adjacent dots. Therefore, in the color printing method of this embodiment, one color is adjacent to each other by three colors.
One pixel is composed of dots.

Next, a color printing method according to the third embodiment of the present invention will be described. In the color printing method of this embodiment, with respect to a color desired to be expressed by a certain dot, three colors of yellow (Y), magenta (M) and cyan (C) constituting the color are used.
This is a method in which only the darkest color of the primary colors is printed at that density. Therefore, when the expression color of one dot is color-separated into three primary colors of yellow (Y), magenta (M), and cyan (C), for example, when the yellow (Y) color is the darkest, the yellow (Y) color When the magenta (M) color is the darkest, the magenta (M) color is printed, and when the cyan (C) color is the darkest, the cyan (C) color is printed. The control circuit 2 of FIG. 1 changes the print data into data for generating heat required for this density, and drives the thermal head 15.

[0016]

As described above, according to the present invention,
You can control the heat generation temperature. Use color thermal paper that can change the color and density that develops according to the temperature change of the heating element of the thermal head. Adjacent 3 dots print the required density of yellow, magenta and cyan, respectively. ,
By expressing the desired color by the combination of these three colors, or by printing only the darkest color of the three primary colors of yellow, magenta, and cyan, which form the color to be expressed, at that density, Since it is possible to perform color printing, the printing speed is increased, and since it is not necessary to perform the fixing operation, the device can be simplified and an inexpensive printer can be provided.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an embodiment of a thermal color printer used in the present invention.

FIG. 2 is a diagram showing color development characteristics of the thermal paper used in the present invention.

FIG. 3 is a diagram illustrating a color printing method according to the first embodiment of this invention.

FIG. 4 is a diagram illustrating a color printing method according to a second embodiment of the present invention.

FIG. 5 is a configuration diagram showing an example of a conventional thermal color printer.

FIG. 6 is a diagram showing color development characteristics of color thermal paper used in a conventional thermal color printer.

[Explanation of Codes] 1 Upper device 2 Control circuit 3 Conveying motor 4, 8, 9 Belt 5 Feeding roller 6 Paper box 7 Thermal paper 10 Feed roller 11 Idler roller 12 Paper detection sensor 13 Solenoid 14 Spring 15 Thermal head 16 Platen 17, 18 Paper Guide

Claims (2)

[Claims] 1. A color thermal paper capable of changing a color and a density generated by a temperature change of a heating element of a thermal head capable of controlling a heating temperature is used, and three adjacent dots are colored yellow, magenta and cyan, respectively. A color printing method for a thermal color printer, which prints a required density and expresses a desired color by a combination of these three colors. 2. A yellow color forming a color expressed by one of the heating elements, using a color thermal paper capable of changing a color and a density of the heating element of a thermal head capable of controlling a heating temperature and changing a color and a density thereof. A color printing method for a thermal color printer, characterized in that only the darkest color among the three primary colors of magenta, cyan and cyan is printed at that density.