| 摘要 |
PURPOSE:To prevent production of noise from a step motor under normal density mode by controlling the driving torque of the step motor variably according to a step rate. CONSTITUTION:A high/low density signal 2 goes to High level under high density mode(HD) and turns transistors 15, 16 ON, OFF, respectively, through a buffer circuit 18. Consequently, a large driving current is fed to a step motor 7 in order to drive the step motor 7 under high torque state. The high/low density signal 2 goes to Low level under normal density mode(LD) and turns the transistors 15, 16 OFF, ON, respectively. Consequently, the step motor 7 is driven under low torque. By such arrangement, production of noise due to driving of the step motor 7 with excessive torque under UD mode can be prevented. |
