An image forming apparatus includes a rotatable image bearing member for bearing a toner image, a toner image forming member for forming the toner image, a transfer member for transferring the toner image onto a transfer material, and a cleaning member for electrostatically collecting toner remaining on the image bearing member after the toner image is transferred onto the transfer material by being supplied from the power source a voltage which has an absolute value smaller than an absolute value of an electrical discharge start voltage and a preset polarity. The image forming apparatus is capable of executing a toner discharge mode for discharging toner from the cleaning member by applying, from the power source to the cleaning member, a voltage which has an absolute value equal to or larger than the absolute value of the electrical discharge start voltage and an identical polarity to the preset polarity.