Patent ID: 7426353

Claim:
An image forming apparatus for transferring and fixing a toner image on a first surface of a sheet in an image forming portion, and thereafter reversing the sheet and again conveying the sheet to said image forming portion, and transferring and fixing a toner image on a second surface of the sheet to thereby form images on the both surfaces of the sheet, said image forming apparatus comprising: a transfer device configured to transfer the toner image to the sheet; a fixing device configured to fix the toner image transferred by said transfer device on the sheet; and speed controlling means configured to control a sheet conveying speed between said transfer device and said fixing device, wherein in a case of forming the image on the first surface of the sheet, said speed controlling means controls the sheet conveying speed between said transfer device and said fixing device on the basis of an amount of a loop formed in the sheet by a difference between sheet conveying speeds of said transfer device and said fixing device, and in a case of forming the image on the second surface of the sheet, said speed controlling means controls the sheet conveying speed between said transfer device and said fixing device on the basis of an average sheet conveying speed of the sheet conveyed between said transfer device and said fixing device when the image has been formed on the first surface.