A paper feeder assembly for an image forming apparatus is configured to sandwich a sheet of paper between a roller and an opposing pressing member and feed the sheet of paper by the roller being rotated. The paper feeder assembly includes a pressure variable member for varying pressurized contact force between the roller and the pressing member. In conjunction with ON/OFF action of a power supply switch provided in a main body of the image forming apparatus, the pressure variable member ensures pressurized contact force enough to fix an image when the power supply switch is turned on, whereas the pressure variable member operates to separate the roller and the pressing member from each other when the power supply switch is turned off.