JPH10181064A - Thermal head driving device and driving method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a thermal head driving device and method that uniformizes print density without carrying out continuous power application to heating elements. SOLUTION: When print data 11 are supplied to a first driver 4A and a second driver 4B as the same information, when a selection signal 12 drives a first heating element 5A for the first line, it is negative logic, and when the signal drives a second heating element 5B for the second line, it is positive logic, an enable signal 13 is supplied to the first driver 4A as the result of taking a logical sum with the negative logic and it is supplied to the second driver 4B as the result of taking a logical sum with the positive logic of the selection signal 12. Therefore, the first driver 5A for the first line and the second driver 5B for the second lien are driven alternately but not simultaneously, thus lowering heat storage.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal head driving apparatus and method, and more particularly, to a thermal head driving apparatus and a driving method having means for controlling the print density of a thermal head.

[0002]

2. Description of the Related Art FIG.
As shown in the figure, the heating element 5 is constituted by a plurality of heating elements 5 arranged in a line, one end of the heating element 5 is connected to the power supply Vcc, the other end is connected to the driver 4, and the print data 1
The heat generated by the heating element 5 is controlled by a pulse generated by being input to the driver 4 with a combination of 1 and the enable signal 13.

[0003]

In the conventional thermal head driving device, when "H" is continuously input to the print data 11, a current flows continuously to the heating element 5 and is gradually stored. Therefore, there is a problem that the print density is extremely different between the head of the line and the end of the line.

[0004] It is an object of the present invention to provide a thermal head driving apparatus and method in which the density difference is reduced.

[0005]

In order to solve the above-mentioned problems, a thermal head driving apparatus according to the present invention comprises a plurality of first heads arranged in a row direction which generates heat based on input print data.
A heating element, a plurality of second heating elements arranged in a column direction of the first heating element and arranged in a row direction, and a first input to which the print data for controlling the first heating element and the second heating element is input. A driver, a second driver, a first OR gate for selectively controlling the first driver from the input selection signal and enable signal, and a NAN for inverting the selection signal
A D-gate and a second OR gate for selectively controlling the second driver based on the output signal inverted by the NAND gate and the enable signal, and alternately energize the first and second heating elements. It is characterized by controlling.

In order to solve the above-mentioned problems, a method of driving a thermal head according to the present invention is characterized in that a plurality of first heating elements arranged in a row direction are heated and then arranged in a column direction of the first heating elements so as to be arranged in a row direction. A plurality of second heating elements are caused to generate heat, and the first and second heating elements are alternately driven to generate heat.

[0007]

Next, a thermal head driving device according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of a thermal head driving device according to an embodiment of the present invention.

As shown in FIG. 1, a thermal head driving device according to an embodiment of the present invention includes a plurality of first heating elements 5A that are arranged in a row direction that generates heat based on input print data 11, and the first heating elements 5A. A second heating element 5B arranged in the column direction of the one heating element 5A and arranged in a row direction;
A first driver 4A and a second driver 4B to which print data 11 for controlling the heating element 5A and the second heating element 5B are inputted, and the inputted selection signal 12 and enable signal 1
A first OR gate 2A for selecting and controlling the first driver 4A from the first and third gates; a NAND gate 3 for inverting the selection signal 12;
A second driver for selectively controlling the second driver based on the output signal inverted by the NAND gate and the enable signal;
And an OR gate 2B.

Next, a method for driving a thermal head according to an embodiment of the present invention will be described with reference to the drawings.

In the method of driving a thermal head according to an embodiment of the present invention, as shown in FIG. 1, print data 11 is supplied to a first driver 4A and a second driver 4B as the same information, and a selection signal 12 is supplied to one line. First heating element 5 of the eye
A is negative logic when driving A, and positive logic when driving the second heating element 5B on the second line.
3 is supplied to the first driver 4A as a result of ORing the negative logic of the selection signal 12 and the second driver 4B
Is supplied as a result of the logical sum of the selection signal 12 and the positive logic, so that the first heating element 4A in the first line
And the second heating elements 4B in the second line are not driven simultaneously, but are driven alternately to reduce heat storage.

[0012]

As described above, according to the thermal head driving apparatus and method of the present invention, the current is always intermittently applied to any one of the heating elements arranged in two lines in the row direction. Therefore, there is an effect that the heat storage of the heating element is reduced and the print density is made uniform.

[Brief description of the drawings]

FIG. 1 is a block diagram of a thermal head driving device according to an embodiment of the present invention.

FIG. 2 is a block diagram of a conventional thermal head driving device.

[Explanation of symbols]

 Reference Signs List 3 NAND gate 2A First OR gate 2B Second OR gate 4A First driver 4B Second driver 5A First heating element 5B Second heating element 11 Print data 12 Selection signal 13 Enable signal

Claims (2)

[Claims] 1. A plurality of first heating elements arranged in a row direction that generate heat based on input print data, and a plurality of second heating elements arranged in a row direction and arranged in a column direction of the first heating element. A first driver and a second driver to which the print data for controlling the first heating element and the second heating element are inputted, and a first OR gate for selectively controlling the first driver based on the inputted selection signal and enable signal A NAND gate for inverting the selection signal, and a second OR gate for selectively controlling the second driver based on the output signal inverted by the NAND gate and the enable signal. A thermal head drive device wherein a heating element is alternately energized and controlled. 2. After the plurality of first heating elements arranged in the row direction generate heat, the plurality of second heating elements arranged in the column direction of the first heating element and arranged in the row direction generate heat. A method of driving a thermal head, comprising: driving a heating element and a second heating element to generate heat.