An image forming apparatus forms an image by transferring a toner image to a sheet, the toner image being formed on an image carrier belt with an elastic layer on a surface. The apparatus includes a rigid blade, an angle detector, an angle changer and a hardware processor. The rigid blade contacts with the image carrier from which the toner image has been transferred to the sheet, so as to clean residue attached on the surface of the image carrier. The angle detector detects an effective contact angle between the surface of the image carrier and an opposed surface of the rigid blade opposed to the image carrier. The angle changer changes the effective contact angle. The hardware processor controls the angle changer according to a detection result by the angle detector to regulate the effective contact angle to a predetermined range.