An image forming apparatus includes an exposure device for exposing an
electrically charged surface of an image bearing member to light to form
an electrostatic image; a developing device capable of collecting a
transfer residual developer remaining on the image bearing member; a
transferring device for transferring a developer image from the image
bearing member onto a transfer medium at a transfer position; and a
controller for executing, during non-image formation, a developer
collecting mode in which a developer of an opposite polarity is collected
into the developing device by driving the image bearing member and by
causing the developer carrying member to stop its rotation or rotate at a
speed slower than a rotational speed thereof during image formation while
generating a potential difference capable of transferring the developer
of the opposite polarity from the image bearing member onto the developer
carrying member.