JPS61241170A - Driving-controlling system for thermal serial printer - Google Patents

Abstract

PURPOSE:To enhance printing quality, by a system wherein dummy data for preheating formed from a recording pattern by calculation are sent to each current passing controlling circuit to perform preheating. CONSTITUTION:Immediately before n-th printing, the dummy data are sent to each of current passing controlling circuits 3-1-3-7, and when (n-1)th piece of printing data is '0' and n-th piece of printing data is '1', preheating is conducted. When the (n-1)th piece of printing data is '1' and the n-th piece of printing data is '1', preheating is not conducted, and heat accumulation is prevented. Heating time for dummy data is set to be shorter than that for normal printing data, whereby preheating is achieved. Accordingly, heat is still left when printing the n-th printing data, so that void is prevented from being generated. In addition, when the (n-1)th and n-th pieces of printing data are '1, 1', preheating is not conducted, whereby trailing due to overheating can be prevented from occurring.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a drive control system for a thermal serial printer that can improve recording quality.

[Conventional technology]

FIG. 4 is a diagram showing an example of a character pattern.

The character pattern shown in this figure consists of a pixel structure of 5×7 dots. Conventionally, a recording head configured by arranging seven heating elements (not shown) in series in the vertical direction is moved in the horizontal direction to selectively and Recording is performed on a recording medium by generating heat intermittently. In this case, when the character pattern shown in Figure 4 is the character H, 1
The first time, all seven heating elements are made to generate heat, the second, third, and fourth times, all the heating elements in one row in the center are made to generate heat, and the fifth time, all seven heating elements are made to generate heat. That is, one central heating element is made to generate heat five times in succession, and the other heating elements are made to generate heat only the first and fifth times. For this reason, heat is accumulated in the central heating element compared to other heating elements, and if the recording head is moved from left to right to perform printing, the left vertical part forming the letter H is The line is recorded by uniform density.

The horizontal line in the center gradually becomes thicker towards the right.

The vertical line on the right side is recorded with uniform yield except for the one dot in the center, and the one dot in the center has the maximum density among all the pixels forming the letter H.

In this way, the frequency at which the heating element generates heat differs for each dot, so if all dots are adjusted to have a uniform amount of heat generated, tailing may occur depending on the number of pixels that make up the nine characters.
There has been a problem in that recording quality tends to deteriorate significantly due to white spots. As a method to eliminate such problems.

Conventionally, 1 shown in FIG.
The one disclosed in Publication No. 0 has been proposed. This device is designed to improve recording quality by controlling the amount of heat generated in stages for each heating element according to the corresponding preceding recording pattern.

FIG. 5 is a diagram showing a drive control circuit in a conventional thermal printer drive control system. In FIG. Outputs a control signal.

2 is a delay circuit for identifying whether the pixel of the preceding recording pattern is "1" or "0"; 3 is a control circuit; ) control the amount of heat generated in stages.

A drive control circuit having the configuration shown in FIG. 5 above is provided for each heating element constituting the recording head, and each conversion circuit
As shown in FIG.
” or “0” and the preceding pixel, i.e. n −1 “1” or “0” of the previously recorded pixel, generates an output signal as shown in FIG. 6, and controls the control circuit. 3 applies the voltage shown in FIG. 7 (al) to the heating element when it is "1.1" and the voltage shown in FIG. 7 (bl) when it is rl and OJ, depending on the output signal of the conversion circuit 1 In this way, by changing the pulse width of the voltage applied to the heating element depending on the heating state of n -1 preceding pixels, it is possible to improve printing quality.

[Problem that the invention seeks to solve]

In the conventional drive control system for thermal printers as described above, a drive control circuit as shown in Fig. 5 must be provided for each heating element that makes up the recording head, which makes the configuration of one circuit extremely difficult. There were problems such as being complicated and expensive. In particular, recently, thermal serial printers with high resolution and consisting of 24 or 32 heating elements have become mainstream. Providing a drive control circuit as shown becomes even more impractical.

The present invention was made to solve this problem by simplifying the configuration of the drive control circuit.

The purpose of the present invention is to obtain a drive control method for a thermal serial printer that can also be sufficiently applied to a thermal serial printer with high print quality.

[Means for solving problems]

The drive control method for a thermal serial printer according to the present invention has a configuration in which dummy data created by calculation from the recording pattern is sent to each energization control circuit for preheating before the regular printing processing time for recording the recording pattern. This is what I did.

[Effect]

In the drive control method of the thermal serial printer of the present invention, before the regular printing processing time for recording the recording pattern, dummy data for preheating created by calculation from the recording pattern is sent to each energization control circuit to perform preheating. By doing.

Try to improve print quality.

〔Example〕

FIG. 1 is a diagram showing a drive control circuit in a drive control system for a thermal serial printer according to an embodiment of the present invention. FIG. 1 shows a drive control circuit of a thermal serial printer equipped with seven heating elements (not shown) as an example. In FIG. Buffer memory that stores
3-1.3-2, ..., 3-7 are energization control circuits that control the amount of heat generated by each heating element, and each energization control circuit 3
-1 to 3-7 are connected to the CPU 4. here.

RO with a built-in program to operate CPU4
M (memory for exclusive use of M) is omitted.

In the drive control circuit configured as described above, the pulse width of the applied voltage is set such that the n+th recording pixel and the nth recording pixel are "1.1".
”, the energization pulse width is determined so that tailing does not occur. In this state, the n-1th pulse is “0”.
In this case, if the nth number is "1", white spots will occur, so in order to prevent this, the CPU 4 performs logic processing using a logic circuit as shown in FIG. 2 before printing the nth number. n
Immediately before the printing time, dummy data is sent to each energization control circuit 3-1 to 3-7, and the n-1th printing data is "0".
”, when the nJ-th print data becomes “1”, preheating is performed.

Further, when the (n-1)th print data is "1" and the n-th print data is "1", preheating is not performed to prevent heat accumulation. Figure 3 shows an example of a character pattern printed with the above dummy data, and as shown in the printed character pattern shown in Figure 1, the heating time of the dummy data is longer than that of the regular printed data. By making it shorter than the heating time, it becomes preheating. This is because heat still remains when printing the nth print data. The white spots that occur in conventional thermal transfer thermal printers are eliminated, and when the print data continues from n-1 to rl and IJ at the In addition, in the above embodiment, the case where dummy data is sent immediately before the regular print data and preheating is performed is explained, but additional bits are sent immediately after the regular print data to prevent the regular print data. Printing may be performed after the print data, and the same effect as in the above embodiment can be achieved.

〔Effect of the invention〕

As explained above, in the drive control method of a thermal serial printer, this invention sends dummy data for preheating calculated from the recording pattern to each energization control circuit before the regular printing processing time for recording the recording pattern. Since the printer is configured to perform preheating, printing quality can be improved.

In addition, the circuit configuration is simplified because there is no need to change the one-time period for each heating element. Moreover, it has excellent effects such as being able to be constructed at low cost.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a diagram showing a drive control circuit in a drive control system for a thermal serial printer according to an embodiment of the present invention.
FIG. 2 is a logic diagram for creating dummy data in the drive control circuit of FIG. 1. FIG. 3 is a diagram showing an example of a character pattern printed with dummy data in the drive control circuit of FIG. 6 is a diagram showing the input and output signals of the conversion circuit in the drive control circuit of FIG. 5, and FIG. 7 is a diagram showing the voltage waveform of the control circuit in the drive control circuit of FIG. 5. FIG. In the figure, 3-1 to 3-7... energization control circuits. 4...CPU (Central Processing Unit), 5...Buffer memory.

Claims (1)

[Claims] A recording head configured by arranging a plurality of heat generating elements is provided, and the recording head is moved relative to the recording medium in a direction intersecting the arrangement direction of the heat generating elements, and the heat generating elements are arranged in accordance with the recording pattern. In a thermal serial printer that performs recording by intermittently generating heat in an element, dummy data created by calculation from the recording pattern is inserted into the regular recording pattern during a fixed periodic time interval during which the recording pattern is recorded. A drive control method for a thermal serial printer characterized by recording in between.