Drive-voltage control device having a switching element for a drive- voltage supply line and an image forming apparatus using the drive- voltage control device

摘要

A drive-voltage control device for a power-saving power-supply circuit provides a control voltage and a drive voltage to a load device connected thereto and controls the supply of the control voltage and the drive voltage so as to achieve a power-saving mode. The drive-voltage control device prevents the load device from being damaged due to on and off of the power-saving mode. The load device is driven by both the control voltage and the drive voltage. A switching element is provided to a power- supply line through which the drive voltage is supplied from the power- saving power-supply circuit to the load device. A timing control circuit controls a timing for switching the switching element so that the switching element is caused to be conductive when a predetermined period has passed after the supply of the control voltage to the load device is begun when the power-saving mode is turned off. The switching element is caused to be nonconductive when the control voltage falls to a predetermined level when the power-saving mode is turned on.