of fig1 of the housing 1 the paper feeding section 10 includes a paper cassette 11 removably attached to the one side portion of the housing 1 a paper supply roller 12 in rolling contact with the uppermost one of sheets p contained in the paper cassette 11 and capable of delivering the sheets p one by one into the housing 1 and a sheet bypass guide 13 for manual paper supply each sheet p delivered from the paper feeding section 10 is regulated for feed timing by a pair of aligning rollers 15 and fed so as to be in rolling contact with the photoconductive drum 2 in a transfer section the photoconductive drum 2 is also surrounded by a pre transfer charger 9 a transfer charger 16 for transferring the developing agent to the sheet to form a visible image thereon and a separation charger 17 for separating the sheet from the photoconductive drum 2 after transfer the transfer section is defined between the photoconductive drum 2 and the transfer charger 16 after the developing agent image visible image is transferred to the sheet the sheet is guided to a fixing unit 20 by a conveyor belt 19 the developing agent is fixed by the pressure and heat of a pair of heat rollers 21 which constitute the fixing unit 20 after the fixation the sheet is discharged onto a tray 23 by a pair of exit rollers 22 after the transfer operation the developing agent remaining on the surface of the photoconductive drum 2 is removed by a cleaning unit 18 the developing apparatus 8.