Sheet processing apparatus, image forming system, and sheet processing method

An image forming system comprising:

• a sheet processing apparatus that includes:
• a stacking unit that stacks conveyed sheets;
• an aligning unit that aligns the sheets stacked on the stacking unit in a sheet conveying direction;
• a binding unit that moves along an end portion of a bundle of the sheets on a binding portion side and performs a binding process for the bundle of the sheets that have been aligned by the aligning unit;
• a pressing unit that presses the bundle of the sheets at the end portion thereof on the binding portion side;
• and
• an interlocking unit that moves the pressing unit in association with a motion of the binding unit, and
• an image forming apparatus that conveys the sheets on which image formation has been performed to the sheet processing apparatus.

A sheet processing method comprising:

• stacking conveyed sheets on a stacking unit;
• aligning the sheets stacked on the stacking unit in a sheet conveying direction by using an aligning unit;
• and
• moving a binding unit along an end portion on a binding portion side of a bundle of sheets, and causing the binding unit to perform a binding process for the bundle of the sheets that have been aligned by the aligning unit,
• wherein the binding process is performed by the binding unit in a state in which a pressing unit that moves in association with movement of the binding unit presses the end portion on the binding portion side of the bundle of sheets.