| 摘要 |
PURPOSE:To enable the temperature of a thermal head to be maintained in a temperature range independent of the ambient temperature, by applying the quantity of energy smaller than the minimum energy necessary for thermal transfer, to heat generating elements not to be operated for thermal transfer. CONSTITUTION:A controlling circuit comprises an n-bit shift register 4 for n heat generating elements 31..., a data (i) transmitted in synchronism with clock pulses CK, and are latched into latch circuits 51 by latch pulses LP. An auxiliary strobe pulse ASP with a predetermined pulse duration is inputted to a NAND circuit 52, and a signal from the latch circuit 51 is also inputted to the NAND circuit 52 through an OR circuit 53 together with a strobe pulse signal SP. By inputting the pulse ASP at a trailing end part of the pulse SP, a signal with such a pulse duration (ASP) that thermal transfer recording can not be performed is given to each of the heat generating elements which are not to be operated for thermal transfer recording, thereby raising to a certain extent the temperature of the heat generating elements which are not to be operated. Accordingly, the temperature of a thermal head can be maintained in a range independent of the ambient temperature, and a high image quality can be obtained. |
