JPS62238764A - Driving system for heat generating resistor row - Google Patents

Abstract

PURPOSE:To reduce a non-printing section and enable efficient printing, by controlling a driving period for a thermal head in proportion to the width of driving pulses. CONSTITUTION:A row of heat generating resistors are divided into 8 blocks, which are sequentially made active (H) by driving pulse signals ENB1-ENB8, whereby printing is conducted. Where a driving period (c) is 8 times the width (b) of driving pulses, the width (b) of the driving pulses and the driving period (c) are uniformly determined according to the temperature (a) of a heat-releasing plate attached to a thermal head 6-1. The temperature of the heat-releasing plate is detected by a thermistor 6-2, and a detection signal is converted into a digital signal by an A/D converter 6-3. The digital signal is applied to an address input of a ROM 6-4 for a pulse width table, and a data output from the ROM 6-4 is sent to a controlling part 6-5. The ROM 6-4 has addresses allocated respectively to five temperature conditions, and stores pulse width information according to each of the temperature conditions. A controlling part 6-5 sequentially outputs the signals ENB1-ENB8 according to the pulse width information from the ROM 6-4. Accordingly, driving can be controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a heat generating resistor array drive system for printing characters and the like on thermal recording paper.

[Conventional technology]

By thermal head! When recording by applying thermal energy to thermal paper, the applied thermal energy is controlled by the IIA recommendation period of the thermal head and the temperature of the heat sink in order to obtain a constant value. (Refer to Japanese Patent Publication No. 55-48631 and Japanese Patent Application Publication No. 54-153647.) The control of the normal thermal energy is carried out in stages by the width of the drive pulse. Third
The figure shows an example of the relationship between the drive cycle and the drive pulse width when the heat sink temperature is 25°C. Also, Figure 4 shows the relationship between the heat sink parts and the drive pulse width, with the total pivot pulse width of 100°C at 25°C.
It is shown as a percentage.

FIG. 2 shows the printing timing when conventionally printing is performed using this type of thermal head. In this example, 1 inch is divided into 8 parts to reduce the amount of printing and labor required for recording. H of ENBI~8 indicates the drive pulse width. Further, the temperature of the heat sink at this time is 25°C. Here, the drive cycle is 0.6 m8)+8=4, Bma, considering one drive pulse with a heat radiation υγ quality of 5 to 20°C.

This is because the purging pulse precision is Q, 5 ms when the temperature of the heat sink is 5 to 20 DEG C. and the drive cycle is 4.8 ms.

[Problems that the invention attempts to solve]

In the conventional example shown in FIG. 2, the heat dissipation temperature is 25°C and the driving cycle is 48m8, so from FIG. 3, the driving pulse width is o, sm.
It becomes s. Therefore, the printing time for one line is 0.5maX8=
Although it is 4 ms, the driving cycle is 4.8 m8, so there is a disadvantage that a non-printing section occurs and the recording efficiency decreases. The object of the invention is to remedy this drawback.

[Means for solving problems]

The above object of the present invention is to provide a thermal head facing a thermal recording paper, a means for generating a driving pulse for generating heat in the thermal head, and a means for controlling the driving period of the thermal head in proportion to the pulse width. This is achieved by a heat-generating resistor array drive method.

〔Example〕

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

FIG. 1 is a timing chart showing the operation of one embodiment of the present invention. In this embodiment, as in the prior art, printing is performed by dividing the heating resistor array into eight parts and sequentially activating each divided resistor block by drive pulse signals ENB1 to ENB8. The driving pulse width is determined based on FIGS. 3 and 4.

Figure @1 is an example of printing when the heat sink temperature is 25℃, and since the driving cycle is 3.2 mg, the driving pulse width is Q from Figure 3.
, 4mg, and can be printed without any blank areas.

If the driving period is 8 times the driving pulse width, then Fig. 3,
Based on FIG. 4, the drive pulse width and drive period are uniformly determined according to the heat sink temperature. This relationship is shown in FIG. Further, a block diagram of a circuit for controlling the pulse width as shown in FIG. 5 is shown in FIG. In FIG. 6, a thermistor 6-2 attached to a heat sink (not shown) of a thermal head 6-1 detects the temperature of the heat sink, and a detection signal is sent to an A/D converter 6-3.
is converted into a digital signal. The converted digital signal is applied to the address input of the ROM 6-4 of the pulse width table, and the data output of the ROM 15-4 is controlled by the control unit 6-5.
Send to. In the ROM 5-4, each address is assigned to one of the five temperature states shown in FIG. 5, and pulse width information corresponding to each temperature state is stored. The control unit 6-5 is a ROM
According to the pulse width information from 6-4, ENB1 to ENB8 are sequentially output.

In this way, drive control as shown in FIG. 5 can be performed.

〔Effect of the invention〕

As explained above, according to the present invention, by controlling the driving period of the thermal head in proportion to the driving pulse width, it is possible to reduce the non-printing section and perform printing efficiently.

[Brief explanation of drawings]

Fig. 1 is a time chart showing the drive timing of the embodiment of the present invention, Fig. 2 is a time chart showing the conventional drive timing, and Fig. 3 is the drive period and drive pulse of the thermal head when the heat sink *i2s °C. FIG. 4 is a diagram showing the relationship between drive pulse width and heat sink temperature. FIG. 5 is a pulse width table set according to an embodiment of the present invention. FIG. FIG. 2 is a block diagram showing an example. ENB3 ++−−−−−−“]1l
B3 ENEI? +++- "]-11111man? Sen 2 4 6 g
f, f, i) Q◆IJIIIR (tnx)
drunkenness 3 imaginary

Claims (1)

[Claims] A heating resistor array including a thermal head that generates heat and records heat on a thermosensitive recording paper by application of a drive pulse, means for generating the drive pulse, and means for controlling a drive cycle of the thermal head in proportion to the width of the drive pulse. Drive system.