An image forming apparatus includes a cartridge having an image bearing member and a developer bearing member that bears a developer, and a detection unit configured to detect if the cartridge is new. A lubricant of a polarity opposite to a polarity of the developer is coated on the developer bearing member, and if the cartridge is detected to be new, prior to start of an image forming operation, a discharging operation of discharging the lubricant from a surface of the developer bearing member onto the image bearing member is performed. When a predetermined time elapses from a start of the discharging operation and before an end of the discharging operation, a potential difference between a surface potential of the image bearing member and a surface potential of the developer bearing member is set smaller than when the discharging operation is started.