| 摘要 |
PURPOSE:To rapidly detect the stepout of a pulse motor even if a printing head is operated at any position by detecting the drive malfunction of the motor. CONSTITUTION:The detected value S3 which is proportional to the curent of a stator coil is compared by a comparator 3 with a reference voltage VX, and when a voltage S3 exceeds the voltage VX, the comparator 3 produces an output signal S4. A one shot pulse generator 4 is triggered by a drive signal S1, and after the prescribed time is elapsed, an output signal S5 is outputted. In case of normal time, since the output signal S4 and the output signal S5 have a timing displacement, the output signal S6 of the NAND circuit 5 does not alter, and a flip-flop 6 is not accordingly set. When a step-out occurs, the output signal S6 of the circuit 5 is altered, the flip-flop 6 is set, and the step-out is detected by the detection signal S8. |
