switching section 15 a reentrant sheet re feeding section 16 and an inverting sheet discharging section 17 a document d placed on the document table of the automatic document feeding apparatus df is conveyed by a sheet feeding section the images on one side or both sides of the document are read out by the optical system of the image reading apparatus sc and read by an image sensor ccd after the analog signal obtained by photoelectric conversion by the image sensor ccd is subjected to in the image processing section 20 analog processing a d conversion shading correction image compression processing etc the image signal is sent to the image exposure unit 3 in the image forming section the processes of charging exposure developing transfer separation cleaning etc are carried out in the image forming section electric charge negative electric charge in the present preferred embodiment is put by the charging unit 2 on the photoreceptor 1 an electrostatic latent image is formed by laser light emission from the image exposure unit 3 and the electrostatic latent image is converted into an apparent image by the developing unit 4 and becomes a toner image the toner image has negative electric charge in the present preferred embodiment next a sheet p stored in the sheet feeding cassette 10 is conveyed from a first sheet feeding section 1 on the other hand the toner remaining on the photoreceptor 1 after transferring is cleaned by the cleaning unit 6 the sheet p is conveyed in synchronization with the toner image by the second sheet feeding section 12 made of a registration roller at this time the skew during conveying is corrected by the sheet p abutting against the second sheet feeding section in other words the second sheet feeding.