| 摘要 |
<p>PURPOSE:To simplify a circuit protecting the breakage of a heating element caused by an electrolytic corrosion. CONSTITUTION:A heating element 50 of a thermal head is connectedly provided between a collector electrode 30c of a PNP-type transistor 30 and a gounded electric potential Vcc. By the ON/OFF operation of the transistor 30, the electric potential of the heating element 50 can be controlled to be equal to the electric potential of a housing 60 connected to the grounded electric potential Vss. In this manner, when the transistor 30 is in an OFF state, there is no difference between the electric potential of the heating element 50 and a power source potential V11. Thus, a switch used for preventing the electrolytic corrosion of the heating element 50 can be omitted from a conventional thermal head, and a circuit can be made simple.</p> |
