| 摘要 |
<p>PURPOSE:To prevent the breakage of an ink ribbon, firing of a printing sheet, etc. when a malfunction occurs in a motor driving circuit, etc., by detecting the presence or absence of a driving pulse of a motor for moving a thermal head, and forcibly interrupting the conduction of a printing heat generator by the stop of the driving pulse. CONSTITUTION:When a motor driving pulse signal 6 is output from a motor driving circuit 1, a pulse detection signal 7 output from a pulse detector 3 becomes a logic '1', a conduction control signal 8 passes an AND gate 5, a thermal head conduction signal 9 becomes a logic '1', and a thermal head is driven. When the motor driving pulse signal 6 is not output due to a malfunction, etc. of the motor driving circuit 1, a pulse detection signal 7 output from the pulse detector 3 becomes a logic '0', and the thermal head conduction signal 9 of the output of the AND gate 5 becomes logic '0' irrespective of the conduction control signal 8. Thus, the thermal head is not driven.</p> |
