Stack limiting unit for sheet processing device

A sheet processing device, comprising:

• a sheet tray configured to hold a plurality of sheets;
• a staple binding unit configured to bind the plurality of sheets with a staple;
• a stapleless binding unit configured to bind the plurality of sheets with a pair of compressing members but without a staple;
• a stopper configured to abut a downstream end portion of the plurality of sheets in a sheet conveying direction;
• and
• a guide member configured to pivot about a fixed shaft in a thickness direction of the plurality of sheets on an upstream side in the sheet conveying direction with respect to the stopper, the fixed shaft not being movable in the sheet conveying direction, the guide member being a plate member, wherein
• a portion of the stopper has a C-shape as viewed from a direction perpendicular to the sheet conveying direction,
• a length of the guide member in the direction perpendicular to the sheet conveying direction is longer than a length of the stopper in the direction perpendicular to the sheet conveying direction, and
• the stopper is disposed near a center of a sheet held on the sheet tray in the direction perpendicular to the sheet conveying direction.