Sheet post-processing apparatus, image forming apparatus and sheet post-processing method
According to one embodiment, a sheet post-processing apparatus includes a machine body, a first roller pair, a tray, a second roller pair, a driving unit, an inlet sensor, a receiving unit and a control unit. The inlet sensor is configured to detect presence or absence of the sheet in the first roller pair driven by the driving unit. The receiving unit is configured to receive, from an image forming apparatus, sheet length information in the sheet conveying direction of the sheet as a target to which the print job is applied. The control unit is configured to control the driving unit to rotate, if the sheet length information indicates special length and the inlet sensor detects a trailing end of the sheet, at least rollers of the second roller pair a predetermined number of times and stop the rollers, the second roller pair nipping the sheet.