| 摘要 |
PURPOSE:To prevent a thermal head from being left in the state of being pressed against a platen roller, by supplying electric power held in an electric power holding means to a return coil by a third switching means to return a solenoid, when electric power supplied to a power source circuit is cut off. CONSTITUTION:When a power source is cut off, an electric charge stored in a capacitor C is discharged, so that a voltage applied to a solenoid 12 falls more slowly than an output from a controlling power source circuit 17. There fore, with the power source cut off, energization of a relay coil LRY is stopped earlier, whereby relay contacts SRY are closed. Since a voltage VS necessary for returning the solenoid is maintained for a period of time Tms after the power source is cut off, a return coil L2 is energized through the relay contacts SRY during this period, whereby the solenoid 12 is returned, a thermal head 6 is moved to a non-printing position, and pressing of the head 6 against a platen roller 4 is released. |
