Patent ID: 8290392

Claim:
An image forming apparatus comprising: an image bearing member, which bears a toner image; a rotatable transfer roller, which is grounded and forms a transfer portion to transfer the toner image formed on the image bearing member onto a recording material; a contact separation mechanism, which brings the transfer roller into contact with the image bearing member and separates the transfer roller from the image bearing member; a driving force transmission portion, which transmits a driving force from a driving source to the transfer roller at least while the transfer roller is separated from the image bearing member; a cleaning member for removing toner adhering to the transfer roller by contacting with the transfer roller while the transfer roller is in contact with and separated from the image bearing member, wherein the cleaning member is electrically conductive and cleans the transfer roller in: (i) a first mode in which the cleaning member cleans the transfer roller while the transfer roller is in contact with the image bearing member and rotates at a first peripheral velocity, and (ii) a second mode in which the cleaning member cleans the transfer roller while the transfer roller is separated from the image bearing member and rotates at a second peripheral velocity, which is smaller than the first peripheral velocity; and a control portion, which controls an electric field applied between the cleaning member and the transfer roller such that an absolute value of the electric field applied between the cleaning member and the transfer roller in the second mode is smaller than an absolute value of the electric field applied between the cleaning member and the transfer roller in the first mode.