An image forming apparatus, such as a printer, having a frame member, wherein there is provided, inside the frame member and on the upstream side of a sheet discharging portion with respect to the sheet conveying direction, a buffering device equipped with a rotary member capable of forward and reverse rotation, and wherein there are formed, along the peripheral surface of the rotary member, a buffering path for causing sheets to stay temporarily, a part of a sheet processing path for conveying sheets to a sheet processing apparatus, and a part of a re-conveying path for re-conveying sheets to an image forming portion.