| 摘要 |
PURPOSE:To obtain a heating time corrector for a thermal head capable of holding constantly the temperature of the head and also of giving high-quality printings by using a system in which voltage for heating elements to be heated one time is detected and integrated, and the time that the integrated value thus obtained reaches a reference voltage is used as a heating time. CONSTITUTION:Black dot number of a letter pattern information 5 is counted 6, and voltage proportional to the count value is sent out through an amplifier circuit 8 to a transistor 9. At the same time as a thermal head 1 begines to heat up by a printing start signal 15, the transistor 9 turns ON and voltage VH proportional to the number of black dots is supplied to the integration circuit 11. Under the condition that the output voltage is below a reference voltage Vref, the output of a comparator 12 becomes high potential and heating is continued, and when the output voltage exceeds the reference voltage Vref, the output of the comparator 12 is inversed, signal is put in the clear terminal of FF10 and 14, and heating is completed. |
