In accordance with an embodiment, a sheet processing apparatus comprises a processing tray, a longitudinal alignment mechanism, a horizontal alignment mechanism and an interlocking mechanism. The processing tray can stack a sheet. The longitudinal alignment mechanism includes a rotatable paddle. The longitudinal alignment mechanism can align the sheets stacked on the processing tray in a sheet conveyance direction. The horizontal alignment mechanism includes a horizontal alignment plate movable in a sheet width direction orthogonal to the sheet conveyance direction. The horizontal alignment mechanism can align the sheets placed on the processing tray in the sheet width direction. The interlocking mechanism interlocks the paddle in the sheet width direction in synchronization with the movement of the horizontal alignment plate in the sheet width direction.

A sheet processing apparatus includes an aligning member and a shift conveying unit. The aligning member is movable in a width direction perpendicular to a sheet conveying direction and presses a sheet stack loaded on a sheet processing tray so as to align the sheet stack in the width direction. The unit is provided on the upstream side of the tray and conveys a sheet, shifting the sheet in the width direction. Being shifted by the unit, sheets are loaded at first and second loading positions on the tray. When sheets are loaded at the first loading position, the aligning member is moved to a first standby position corresponding to the first loading position in advance. When sheets are loaded at the second loading position, the aligning member is moved in advance to a second standby position corresponding to the second loading position.

An example method for picking a media sheet from a media tray, the method comprising: controlling a media picker to perform a pick procedure to pick the media sheet from the media tray; upon detecting an error condition in the pick procedure, translating the media sheet in a direction within a plane of the media sheet; and controlling the media picker to retry the pick procedure to pick the media sheet from the media tray.

A sheet processing apparatus includes a controller configured to control operations of the pair of aligning members such that a sheet bundle disposed on a first stacking portion is aligned by the pair of aligning members of the pair of aligning members at a position shifted to a side of one aligning member in a width direction perpendicular to the discharge direction of a sheet with respect to a sheet discharge range in which a sheet is discharged at the time of discharging the sheet from a discharge portion, and, before the aligned sheet bundle is discharged to a second stacking portion by a bundle discharge portion, the other aligning member of the pair of aligning members is moved to the outside of the sheet discharge range in the width direction.