JPS6127270A - Thermal printer - Google Patents

Abstract

PURPOSE:To make it possible to simply perform the adjustment of a recording position, by electrically adjusting the recording position by each thermal head. CONSTITUTION:Thermal heads 11, 12 are provided to a carriage 13. 24 heat generating resistors #4-#27 in a range, where the recording position by the thermal head 11 coincides, are made selectively effective from 32 dots of heat generating resistors of the thermal head 12 by a selection circuit 21 and selectively driven corresponding to a recording signal. By this method, the shift (y) of the recording position in a Y-direction can be electrically suppressed within one pitch (p) even at max. The timing of clock pulses applied to the drive circuit 14 of the thermal head 11 and the drive circuit 24 of the thermal head 12 from a clock generation circuit 18 can be adjusted by changing the delay times of delay circuits 17, 20. By this method, the shift (x) in an X-direction can be corrected electrically and high quality recording is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a thermal printer in which a plurality of thermal heads are provided on the same carriage.

(Prior Art) In order to improve the recording accuracy of a thermal printer, for example, as described in Japanese Patent Laid-Open No. 55-156080, a carriage equipped with a plurality of thermal heads is moved back and forth. A device configured to perform recording has been proposed.

FIG. 2 is a block diagram showing an example of such a thermal printer. In FIG. 2, reference numeral 1 denotes a platen, and a thermal recording paper 2 that develops color when heated is pressed against the platen 1 by a paper pressing roller (not shown). Reference numeral 3 denotes a carriage that is guided by a guide shaft 4 and reciprocates in a direction X perpendicular to the moving direction Y of the thermal recording paper 2. The carriage 3 connects a drive belt 7, such as a timing belt, which is wound between a drive pulley 5 and a driven pulley 6 and which is locked at both ends to the carriage 3.
It is reciprocated by being driven by a motor 8 via the motor 8. When a timing belt is used as the drive belt 7, the drive pulley 5 and the driven pulley 6 are provided with a tooth profile that matches the tooth profile carved on the inside of the timing belt. On the carriage 3, for example, as shown in FIG. 3, there is a heating resistor array T including a plurality of heating resistors along a direction perpendicular to the width direction of the thermal recording paper 2.
Two thermal heads 9 with E arranged at a predetermined pitch
, 10 are provided along the moving direction X of the carriage 3 at an interval (L/2) that divides the effective recording width of the thermal recording paper 2 into two.

Recording by a thermal printer with such a configuration is carried out by selectively driving the heat-generating resistors TE of each thermal head 9 and 10 to generate heat, and pressing the heat-sensitive recording paper 2 against the carriage 3.
This is performed by reciprocating the platen 1 by L/2 in the direction of the arrow X and intermittently driving the platen 1 in the direction of the arrow Y for each recording of one line. Here, focusing on the moving distance of the carriage 3, it is only 1/2 of the effective recording width of the thermal recording paper 2, which is 1/2 compared to the No. 1 printer in which the carriage is equipped with only one thermal head. Recording can be done in an amount of time.

(Problems to be Solved by the Invention) However, with such a configuration, when paying attention to the recording results, it is found that due to variations in the precision of the parts of the thermal heads 9 and 10, variations in the mounting position on the carriage 3, etc. As shown in Figure 4, the recording position deviation x in the X and Y directions,
y, which may cause deterioration in recording quality.

In order to correct this misalignment of the recording position, it has been proposed, for example, to insert a mechanism that can mechanically finely adjust the thermal head 9 and 10 when attached to the carriage 3, but this would complicate the structure and cause the assembly to be difficult. ,i! The drawback is that it requires a large amount of man-hours.

The present invention has been made in view of the above problems, and an object thereof is to realize a thermal printer in which the recording position of each thermal head can be easily adjusted.

(Means for Solving the Problems) The present invention that achieves this object is characterized in that, in a thermal printer in which a plurality of thermal heads are provided on the same carriage, the recording position of each thermal head is electrically adjusted. That is.

(Example) Hereinafter, an example of the present explosion will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing the main parts of an embodiment of the present invention.

In FIG. 1, 11 and 12 are thermal heads provided on the same carriage 13.

In one thermal head 11, a heating resistor row TE consisting of, for example, 24 heating resistors #1 to #24 is arranged at a constant pitch p, and in the other thermal head 12, a heating resistor row TE is arranged at a constant pitch p. A heating resistor array TE consisting of, for example, 32 heating resistors #1 to #32 of equal size is arranged. 14 is thermal head 1
1 is a drive circuit, and 15 is a drive circuit for the thermal head 12.

The drive circuit 14 is supplied with a recording signal from a recording signal input terminal 16 as well as clock pulses sent from a clock generation circuit 18 via a delay circuit 17 . The drive circuit 15 is supplied with a recording signal from a recording signal input terminal 19, and is also supplied with a clock pulse sent from a clock generation circuit 18 via a delay circuit 20, and is further supplied with a recording signal by the heating resistor array TE of the thermal head 11. A selection signal is provided from a selection circuit 21 comprising a dip switch or the like for selectively activating the heating resistor in a range corresponding to the position.

The operation of the device configured in this way will be explained. If a recording operation is performed with the thermal heads 11 and 12 simply attached to the carriage 13, the results shown in FIG. Similarly, recording position deviations x and ■ may occur in the X and Y directions.

Such a shift y in the Y direction is corrected by selectively activating the heat generating resistors in the heat generating resistor array of the thermal head 12 according to the recording position of the thermal head 11. In other words, if the thermal head 11 is to record 24 dots of characters, symbols, etc., the selection circuit 21 will match the recording position of the thermal head 11 among the 32 dots of the heating resistor of the thermal head 12. The 24 heating resistors #4 to #27 in the range are selectively enabled and selectively driven in accordance with the recording signal. Thereby, the deviation y of the recording position in the Y direction can be electrically suppressed to within one pitch at the maximum, and high quality recording can be obtained. Next, regarding the deviation x in the X direction, the drive circuit 14 of the thermal head 11 and the thermal head 1
The timing of the clock pulse applied from the clock generation circuit 18 to the second drive circuit 15 is adjusted by changing the delay time of the delay circuits 17 and 20.

As a result, the deviation x in the X direction can be electrically corrected, and high quality recording can be obtained.

In the above embodiment, an example of a thermal printer using heat-sensitive recording paper has been described, but similar effects can be obtained with a thermal transfer printer in which a plurality of sets of thermal transfer recording mechanisms are provided on the same carriage. Further, in the above embodiment, an example of two thermal heads was explained, but there may be three or more. Furthermore, either the X direction or the Y direction may be corrected by electrical means such as the present invention, and the other may be corrected by a conventional mechanical fine adjustment mechanism. Further, in the above embodiment, an example is shown in which a dip switch is used as the selection circuit 21, but the selection may be controlled by software.

(Effects of the Invention) As described above, according to the present invention, it is possible to realize a thermal printer using a plurality of thermal heads in which the recording position of each thermal head can be easily adjusted.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing the main parts of an embodiment of the present invention, Fig. 2 is a block diagram showing an example of a thermal printer using two thermal heads, and Fig. 3 is a block diagram showing an example of a thermal printer using two thermal heads. FIG. 4 is a block diagram showing an example of a thermal head, and FIG. 4 is a diagram showing an example of recording by the apparatus of FIG. 2. 11.12... Thermal head 13... Carriage 14.15... Drive circuit 1
6.19...Record signal input terminal 17.20...Delay circuit 18...Clock generation circuit 21...Selection circuit TE...Heating resistor array patent applicant Roku Konishi Photo Industry Co., Ltd. Agent Man
Bento priest Fuji Ijima Jigai 1 person

Claims (3)

[Claims] (1) A thermal printer in which a plurality of thermal heads are provided on the same carriage, in which the recording position of each thermal head is electrically adjusted. (2) Each thermal head has a different number of heating resistors of the same size arranged at the same pitch, and the recording position is determined by selectively driving the heating resistors within the range where the recording position coincides. The thermal printer according to claim 1, characterized in that the thermal printer is adjusted. (3) The thermal printer according to claim 1, wherein the recording position is adjusted by adjusting the timing of a clock pulse applied to each thermal head.