To prevent toner from adhering to an image information writing means by disposing a sheet member which is brought into slidably contact with the surface of a drum between an electrifying device and the image information writing means.

The electrifying device 51, the sheet member 53, an optical writing unit (LED head array) 6, a developing device unit 7, and a transfer device 8 are disposed on the periphery of the photoreceptor drum 5 along a rotating direction (shown by an arrow Y) in order. The drum 5, the device 51, a memory removing brush 52, and the member 53 are integrally unitized to a unit housing, and can be taken out from a device main body by opening an intermediate cover with the unit 7. The member 53 is desirably constituted of a conductive sheet which has such elasticity as that of urethane and whose resistance value is high (106 to 108 Ω), besides, the potential of the surface of the drum 5 can be smoothed by the impressing of a voltage after electrification.