| 摘要 |
PURPOSE:To reduce power loss by providing a circuit which sets the power source of a drive system at the prescribed high level, and at a low level when a drive circuit is operating and waiting, respectively. CONSTITUTION:A switching regulator 6 comprising the power source device of a printer turns on and off a switching element at high frequency so as to supply the drive system power source V1, and a feedback circuit 8 composed of a potential deciding circuit 9 and an error amplifier circuit 10 stabilizes said element. Thus the drive system power source V1 is switched to a voltage at a normal output level and a voltage at a low level when the printer is in operation and on standby, respectively. Accordingly signals at high and low levels enter into a logical signal line S when the printer is in operation and on standby, respectively. Then a switching transistor Tr1 is turned on and off to switch the output level of the drive system power source V1.
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