Sheet processing apparatus having post-processing section, and image forming apparatus having the sheet processing apparatus

An image forming apparatus comprising;

• an image forming section configured to form an image on a sheet;
• a convey unit configured to convey a sheet;
• a first stacking unit on which the sheet conveyed by the convey unit is stacked through a first convey path;
• a second stacking unit on which the sheet conveyed by the convey unit is stacked through a second convey path;
• a switching unit configured to switch between a first position at which the conveyed sheet is led to the first convey path, and a second position at which the conveyed sheet is led to the second convey path;
• a buffer path, disposed at a location of upstream of the switching unit, into which the conveyed sheet once entering the first convey path or the second convey path and subsequently reversely conveyed is received;
• and
• a control unit configured to control the convey unit and the switching unit so as to perform a buffering process of overlaying the conveyed sheet conveyed from the buffer path and another sheet subsequently conveyed by the convey unit,
• wherein the control unit controls the convey unit and the switching unit such that the second convey path is used by the buffering process when the conveyed sheets to be received into the buffer path is ejected to the second stacking unit, and that the first convey path and not the second convey path is used by the buffering process when the conveyed sheet to be received into the buffer path is ejected to the first stacking unit.