Patent ID: 7644919

Claim:
A sheet bundle aligning method for forming a sheet bundle by aligning end portions, in a conveying direction, of sheets supplied to a compiling tray, on which the conveyed sheets are stacked, the method comprising: counting sheets supplied to said compiling tray, the sheets having undergone a predetermined post-processing, which is a sheet folding processing; correcting the number of said counted sheets based on said process performed for the sheets supplied to the compiling tray; pushing a rotary member against a surface of a sheet in synchronization with said sheet, and conveying said sheet to a reference wall for aligning the end portions, in the conveying direction, of the plurality of sheets; changing a conveyance force of said rotary member according to the corrected number of sheets; and changing a position of a regulating guide by following a change of a reference position of the rotary member according to the corrected number of sheets, wherein the reference position of the rotary member is in the direction of thickness of the sheet, and the regulating guide regulates a position of said rotary member in said direction of thickness of a sheet by contacting with said sheets.