A transfer bias voltage supplier supplies, to a transfer member, a transfer bias voltage of a polarity opposite to the polarity of toner. The absolute value of transfer bias voltage to be supplied to the transfer member when a leading/trailing end of the sheet is passed through the nip portion is set smaller than when a toner image transfer region of the sheet is passed through the nip portion. A separation bias voltage supplier supplies, to a discharging electrode member, a separation bias voltage of a polarity opposite to the polarity of transfer bias voltage. The absolute value of separation bias voltage to be supplied to the discharging electrode member when the leading/trailing end of the sheet is passed through a discharging gap is set smaller than when the transfer region is passed through the discharging gap.