A post processing apparatus is attachable to an image forming apparatus. In a state in which a concavely curled recording material is placed on a second placement unit, when a plurality of the recording materials which are convexly curled are discharged to the second placement unit, a control unit causes a post processing unit to perform specified post processing on at least one recording material of the plurality of recording materials, causes a discharging unit to discharge the at least one recording material to the second placement unit, and after the discharge, causes the post processing unit to perform the specified post processing on the recording material or the recording materials of the plurality of recording materials other than the at least one recording material.

A sheet processing device includes a tape binding processing unit, a paper discharge unit, and a control unit. The tape binding processing unit performs tape binding processing on a sheet bundle. The paper discharge unit discharges the sheet bundle subjected to the tape binding processing onto a paper discharge tray. The control unit is configured to control at least one of the tape binding processing unit and the paper discharge unit, such that a first tape binding of the first bundle of sheets and a second tape binding of the second bundle of sheets are not in contact with each other when the first bundle of sheets and the second bundle of sheets are stacked on the paper discharge tray.

A post processing apparatus is attachable to an image forming apparatus. In a state in which a concavely curled recording material is placed on a second placement unit, when a plurality of the recording materials which are convexly curled are discharged to the second placement unit, a control unit causes a post processing unit to perform specified post processing on at least one recording material of the plurality of recording materials, causes a discharging unit to discharge the at least one recording material to the second placement unit, and after the discharge, causes the post processing unit to perform the specified post processing on the recording material or the recording materials of the plurality of recording materials other than the at least one recording material.