| 摘要 |
<p>PURPOSE:To obtain a method of driving a thermal head, wherein a one shot multivibrator for feeding a large electrid power to the head when the driving is started is provided in a circuit for driving the thermal head, so that a maximum temperature required for printing is attained within a short period, and there is no over- heating of a heating resistor. CONSTITUTION:The one shot multivibration OS is actuated at the rising of a printing command signal P to turn a transistor T1 on to bypass a resistor R. At the same time, since a transistor T2 is turned on by the printing command signal P, a large electric power is fed to the heating resistor TH to rise to a temperature Th within a short period. Thereafter, the transistor T1 is turned off, the voltage is lowered to a voltage needed to retain the temperature Th by the resistor R, and the temperature Th is kept until the completion of the feeding. According to this method, as a time (d) to reach a printing temperature Tp at a printing position P is short, high speed printing becomes possible, and in addition since the maximum temperature of the heating resistor would not rise more than needed, the fatigue by heat or the like can be prevented.</p> |
