| 摘要 |
PURPOSE:To enable the automatic supply of application voltage optimum to set printing density even when a thermal head was replaced, by providing a printing resistor element and a control element for controlling the voltage applied to said resistor element to a common substrate. CONSTITUTION:A control resistor element 186 is provided on substrate 181 common to a printing resistor element 182 so as to be independent of the element 182 and connectable to the outside. When a thermal head 18 is attached to a thermal printer, a resistance measuring circuit 25 is connected to both terminals of the element 186 and the output terminal of a voltage generation circuit 26 is connected to the common electrode of the printing resistor element 182 while a drive circuit is connected to the individual electrode of the element 182. The resistance value of the control resistor element 186 is automatically measured by the resistance measuring circuit 25 and a voltage control circuit 27 controls the output voltage of the voltage generation circuit 26 to the optimum value set corresponding to printing density on the basis of the measured value. Therefore, optimum voltage corresponding to set printing density is automatically applied to the printing resistor element 182 even when the thermal head 18 was replaced. |
