An image forming apparatus includes: a pattern determination information calculator for calculating printing pattern determination information on an original; a pressure changer for changing the pressure of a pressing member of a cleaning device; and a controller for varying the pressing force of the pressing member by controlling the pressure changer in accordance with the printing pattern determination information calculated by the pattern determination information calculator. The controller controls the contact pressure driver of the pressing roller so as to weaken the pressing force when that controller determines that printing paper printed with high density patterns or high coverage patterns will be passed through.