| 摘要 |
PURPOSE:To improve the printing quality, by comparing the current and past temperature levels of a thermal head and determining the width of pulse being applied onto the thermal head. CONSTITUTION:A thermistor 17 for detecting the temperature of a head is provided in a thermal head 6 arranged at a transfer section A. When a detection signal of current head temperature is inputted from the thermistor 17 to a CPU 13, the current head temperature is compared with a past head temperature being inputted predetermined time before and stored in a RAM 12 or a buffer RAM. If the comparison results, shows that the head temperature is lowering the CPU 13, determines the width of pulse being applied corresponding to the current head temperature. At the same time, a predetermined pulse width is subtracted from the pulse width corresponding to the head temperature so as to determine the width of pulse being applied actually onto the thermal head 6, then a signal is transmitted to a driver 15 so as to apply voltage onto the thermal head 6. If it is judged that the head temperature is increasing, the predetermined pulse width is added to the pulse width corresponding to the head temperature. |
