An image forming apparatus of the present invention includes a sheet affixed at one edge portion and including a flat surface in the other edge portion. The flat surface is formed with a plurality of grooves each extending over the image forming range of a photoconductive drum perpendicularly to the direction in which the surface of the drum moves. The sheet is deformed such that the flat portion contacts the surface of the drum. In this condition, the downstream edges of the grooves in the above direction shave off the surface of the drum a plurality of times during one rotation of the drum, thereby obviating filming on the drum.