JPH0371859A - Thermal head - Google Patents

Abstract

PURPOSE:To make it possible to minimize feed irregularities even in continuously variable recording by providing even/odd-number control elements for image selection and block control terminals for block selection as a drive circuit for semi-conductor switching elements which control the energization of thermal resistors of a thermal head. CONSTITUTION:Printing energy required for recording is provided by controlling transistors 3, 4 and thereby controlling the energization time of thermal resistors 1, 2. In this case, the transistors 3, 4 are controlled by control circuits 5, 6, even/odd-number control elements 7, a block control element 8 and image signal input terminals 9, 10. In addition, image signal input terminals 9, 10 are constituted so that the control circuits 5, 6 allow recording by an image signal from a shift register 11, if the content of the shift register 11 is black pixels when a latch signal is connected from a latch signal terminal 12. Thermal resistors 1, 2 can be controlled so that they record data selectively by selecting the thermal resistors 1, 2 using the even/odd-number control terminals 7 and allowing a record permitting signal to be connected from the block control terminal 8.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a thermal head, and more particularly to a drive circuit for a thermal head.

[Conventional technology]

Conventional thermal heads are divided into multiple blocks, each consisting of a row of heat-generating resistors, and energization is applied to each block.

[Problem to be solved by the invention]

In the conventional thermal head mentioned above, the continuous heating resistors that are energized at the same time are energized block by block and 1-1 multiple blocks sequentially and time-sequentially, so when the running of the recording paper is continuously variable. However, this method has the disadvantage that uneven recording tends to occur. Another disadvantage is that it is not easy to carry out processing such as thinning out image signals to lower the printing rate in order to reduce power consumption.

[Means to solve the problem]

The thermal head of the present invention includes heating resistors arranged in a row, a semiconductor switch element provided to control energization to each of the heat generating resistors, and a semiconductor switch element provided to individually control the semiconductor switch elements. a control circuit section, an even/odd control terminal provided for dividing and energizing the control circuit section between even-numbered rows of each of the semiconductor switch elements (each of the heat generating resistors), and the semiconductor switch element. It has a block control terminal provided for dividing into a plurality of blocks and energizing them.

〔Example〕

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

FIG. 1 is a circuit diagram showing a part of an embodiment of the present invention, in which the n-th and (n+1)-th heating resistor sections are representatively shown. (However, n=2m: m is an integer) The n-th and n+1-th heating resistors], 2 are connected in series with transistors (semiconductor switch elements) 3 and 4, and control the transistors 3 and 4. By doing so, the energization time of the heating resistors 1 and 20 is controlled, and printing energy necessary for recording is provided.

At this time, the transistors 3 and 4 are connected to the control circuit 5.6.
, an even/odd control terminal 7, an output control terminal 8, and image signal input terminals 9 and 10.

It was. The image signal input terminals 9 and 1o are connected to the shift register 11.
When a latch signal is input from the latch signal terminal 12, if the content of the shift register 11 is a black pixel,
The control circuits 5 and 6 are configured to be in a recordable state. Note that the shift register 11 has an image signal input terminal 13 and an image signal input terminal 1 in order to input an image signal from the outside.
3 and an image signal transfer lock input terminal 14.

Therefore, in this drive circuit, heating resistor 1 or 2 is selected by using even/odd control terminal 7, and by inputting a recording permission signal from block control terminal 8, heating resistor 1 or 2 is selectively selected. It is possible to control the recording operation. That is, the configuration is such that it is possible to control block division printing and division printing of even-numbered pixels and odd-numbered pixels within a block at the same time.

FIG. 2 is an overall configuration diagram of an embodiment of the present invention.

Heating resistor row 21 (the heating resistor l in FIG. 1).

2) are each connected in series with a transistor array 22 (corresponding to transistors 3 and 4 in FIG. 1).

The transistor array 22 is individually 0N10FF controlled for each pixel by a transistor control section 23 (corresponding to the control circuits 5 and 6 in FIG. 1) for each transistor. The transistor control section 23 is controlled by input signals from an even/odd control terminal 24, block control terminals 25 and 26, and an image signal from a shift register 27. That is,
The image signal is externally input to the shift register 27 from the image signal input terminal 28 in synchronization with the transfer lock from the transfer logic input terminal 3o, and is set in the transistor control section 23 by a latch signal from the latch signal terminal 29. At the same time, the transistor control section 23 controls the even/odd control terminal 24
An even numbered pixel or an odd numbered pixel is specified. next,
When a recording permission signal is input from the block control terminal 25 or 26, the transistor corresponding to the black pixel of the block is turned on, the heating resistor is energized, and recording is performed on the recording paper. (This figure shows an example in which the number of block divisions is two, odd and even blocks.) FIG. 3 is an example of a timing diagram for driving the thermal head of FIG. 2. This figure is an example of recording one line by printing even-numbered pixels (odd-numbered pixels) in the order of the first block and second block, and then printing the odd-numbered pixels (even-numbered pixels) in the order of the first block and the second block. It shows. At this time, it is easy to see that the maximum value of the recording current is the same as when printing is performed in four blocks using a conventional thermal head.

In addition, in the embodiment of the present invention, a semiconductor switch element (transistor array 22) and a control circuit (transistor control section 2
3), even/odd control terminals, and block control terminals are integrated and mounted on the thermal head as a drive circuit.

〔Effect of the invention〕

As described above, the present invention has an even/odd control terminal for pixel selection and a block control terminal for block selection as a drive circuit for a semiconductor switch element (transistor) that controls the energization of a heating resistor of a thermal head. (1) Control that can reduce feeding unevenness even in continuously variable recording is possible.

(2) The maximum current during recording can be reduced without deteriorating the image quality of recording.

(3) The image signal can be easily thinned out on a pixel by pixel basis.

There is an effect.

1.2... Heat generating resistor, 3, 4... Semiconductor switch element, 5, 6... Control circuit section, 7
, 24...Even/odd control terminal, 8, 25.26...
...Block control terminal, 9,10... Image signal input terminal, 11゜27... Shift register,
12.29... Latch signal terminal, 13.28.
... Image signal input terminal, 14°30 ... Transfer lock input terminal, 15.31 ... Inverter, 16.32 ... Recording power supply, 21.・・・・・・
- Heating resistor array, 22...transistor array, 23...transistor control section.

Claims (2)

[Claims] (1) Heat generating resistors arranged in a row, a semiconductor switch element provided to control energization to each of the heat generating resistors, and each of the semiconductor switch elements (each of the heat generating resistors)
a control circuit section provided to individually control the semiconductor switch elements (heating resistors); / A thermal head characterized by having an odd control terminal and a block control terminal provided for dividing each of the semiconductor switching elements (each of the heating resistors) into a plurality of blocks and energizing them. (2) Claim (1) characterized in that the semiconductor switch element, the control circuit section, the even/odd control terminal, and the block control terminal are integrated and mounted on the thermal head as a drive circuit. Thermal head listed.