| 摘要 |
<p>PURPOSE:To prevent an electric conduction to a thermal head when an equipment is not used and to prevent an overheat of the thermal head when the equipment is used. CONSTITUTION:Switch elements Q1, Q2 are provided between a battery power source input part (VB) and a common connecting part of a thermal head. A circuit is so formed that the switch elements Q1, Q2 are cut by interrupting a power source voltage Vcc to a control part. In addition, when the overheat of the thermal head is detected, the switch elements Q1, Q2 are cut. In this manner, an error electric conduction to the thermal head when an equipment is not used is prevented, whereby the damage of the thermal head is prevented, and an electrocorrosion and a migration are prevented. Furthermore, the damage of the thermal head in an overheat state is also prevented.</p> |
