Patent ID: 7281707

Claim:
An aftertreatment apparatus comprising: a common conveying path for conveying sheets having images formed thereon by an image forming unit and a sheet to be inserted into the sheets in an order in which the sheets have been carried in: an aftertreatment unit for forming a sheet bundle of the sheets conveyed through said common conveying path, and performing a set aftertreatment on the sheet bundle; a sheet thickness detecting sensor for detecting a thickness of each sheet conveyed on said common conveying path; and a controller for accumulating the thicknesses of the sheets detected by said sheet thickness detecting sensor to calculate a thickness of the sheet bundle, and controlling said aftertreatment unit so as to change the set aftertreatment to another aftertreatment when the calculated thickness of the sheet bundle reaches a predetermined value, wherein said aftertreatment unit has a containing portion into which the sheets conveyed through said common conveying path are carried in an order of conveyance and are contained in a bundle shape, a stapler for stapling a central portion of the sheet bundle contained in said containing portion, and a folding member for folding the sheet bundle at a central portion of the sheet bundle, the set aftertreatment is a treatment of stapling the central portion of the sheet bundle contained in said containing portion by said stapler, and folding the stapled sheet bundle at the central portion of the sheet bundle by said folding member, and the another aftertreatment is a treatment of folding the sheet bundle contained in said containing portion at the central portion of the sheet bundle by said folding member without stapling the central portion of the sheet bundle contained in said containing portion by said stapler.