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.

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.

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.