A sheet processing apparatus includes a sheet processing unit that processes a sheet placed on a placing tray, a discharge roller that discharges the sheet processed on the placing tray to a stacking tray, a conveyance roller that discharges a sheet to the placing tray or conveys a subsequent sheet from upstream to downstream of the discharge roller and switchback-conveys the subsequent sheet upstream again, and a standby path (branch path) that keeps the sheet switched back by the conveyance roller on standby. The subsequent sheet is conveyed to a downstream side of the discharge roller by the conveyance roller and then returned to an upstream side again by switchback conveyance. During the switchback conveyance, the discharge roller nips and discharges the sheets on the placing tray to the stacking tray.

A sheet processing apparatus includes a stacking portion on which sheets targeted for sheet processing are stacked. In the apparatus, a control unit generates, in a buffer section provided in a conveyance path for conveying sheets to the stacking portion, a sheet bundle in which positions of sheets conveyed on the conveyance path are shifted in sequence to an upstream side in a conveyance direction and overlapped. An alignment unit performs alignment processing in the conveyance direction on the sheet bundle stacked on the stacking portion. A processing unit performs sheet processing on the sheet bundle on which the alignment processing has been performed. The control unit controls shift amounts of the positions of the sheets when the sheets are overlapped in the buffer section in sequence, according to sizes of the sheets conveyed on the conveyance path.

A sheet processing apparatus includes a stacking portion on which sheets targeted for sheet processing are stacked. In the apparatus, a control unit generates, in a buffer section provided in a conveyance path for conveying sheets to the stacking portion, a sheet bundle in which positions of sheets conveyed on the conveyance path are shifted in sequence to an upstream side in a conveyance direction and overlapped. An alignment unit performs alignment processing in the conveyance direction on the sheet bundle stacked on the stacking portion. A processing unit performs sheet processing on the sheet bundle on which the alignment processing has been performed. The control unit controls shift amounts of the positions of the sheets when the sheets are overlapped in the buffer section in sequence, according to sizes of the sheets conveyed on the conveyance path.

An output device communicably connected with a post-processing apparatus for executing post-processing on an output product output from the output device, the output device includes circuitry to receive a processing setting pattern that is determined in accordance with an output condition of the output product and corresponding to an operation to be performed by the post-processing apparatus, the output condition, and image data of an image to be formed on the output product and control output of the image data using the post-processing apparatus based on the processing setting pattern and the output condition.