Patent ID: 8391739

Claim:
An image forming apparatus, comprising: an image carrier for carrying toner on a surface thereof; a charging part for uniformly charging the surface of the image carrier; an exposure part for forming an electrostatic latent image by performing an exposure operation, based on image data, on the surface of the image carrier after the image carrier is subjected to a charging operation by the charging part; a developing part for developing the electrostatic latent image formed on the surface of the image carrier by using the toner; a transfer part for transferring a toner image formed on the surface of the image carrier, to a predetermined recording medium; a cleaning roller that has a circumferential surface coming into sliding contact with the surface of the image carrier and carrying the toner, and that removes deposits that are deposited on the surface of the image carrier by using the toner that the circumferential surface carries; a print ratio detector for detecting a print ratio of an image formed during an image formation period in which an image forming operation for forming an image onto the image carrier based on the image data is performed; and a roller controller for determining, based on the print ratio detected by the print ratio detector, whether a removal capacity of the cleaning roller to remove the deposits needs to be increased or not, and then controlling a rotation operation of the cleaning roller in response to a result of the determination, wherein the print ratio indicates a ratio of an area in which the toner is deposited to an area of the image formed on the recording medium, and the roller controller rotates the cleaning roller such that the circumferential surface of the cleaning roller moves downward at a contact area between the cleaning roller and the image carrier in the same direction as the surface of the image carrier, and that the circumferential surface scoops the toner upward on the far side of the contact area, and when the print ratio detected by the print ratio detector is smaller than a predetermined threshold value, the roller controller determines that the removal capacity of the cleaning roller to remove the deposits needs to be increased, and makes the rotation speed of the cleaning roller during a non-image formation period where the image forming operation is not performed, greater than the rotation speed of the cleaning roller during the image formation period.