| 摘要 |
PURPOSE:To enable to obtain a dot pattern with uniform density, by a method wherein a heating resistance element of the same kind as that of heating resistance elements for recording provided on a heat-sensitive head of a heat-sensitive printer is additionally provided in proximity to the heating resistance elements for recording, and the temperature of the elements is detected at the time of passing an electric current for printing. CONSTITUTION:To detect the temperature at the current-passing time of the heating resistance elements Rh1-Rhn for recording which are selectively driven by a printing action, the heating resistanc element Rhz of the same kind as that of the elements Rh1-Rhn is additionally provided in proximity to the elements Rh1-Rhn on the thermal head 1. Each of the resistance elements Rh1-Rhn and Rhz has a positive or negative temperature coefficient, and when the resistance elements Rh1-Rhn are selectively driven by the printing action, the temperature of the head 1 is raised and the resistance values of the elements Rh1-Rhn and Rhz are changed. The change in the resistance value of the element Rhz is detected by a resistance-detecting circuit 4, and an output voltage of a voltage-controlling circuit 3 is controlled by the detection output. Accordingly, the elements Rh1-Rhn are provided with voltages corresponding to the temperature thereof, and are heated to a fixed temperature. |
