Patent ID: 7997569

Claim:
A sheet processing method of a sheet processing apparatus including a stacker that holds a sheet bundle and can move substantially in parallel to a sheet surface of the sheet bundle, an alignment roller that can come in contact with and be separated from a sheet surface of a sheet held by the stacker and causes the sheet to be abutted against a reference position in the stacker and to be aligned by bringing a rotating roller surface into contact with the sheet, and a stapler to perform a stapling process on the sheet bundle which is aligned by the alignment roller and is moved to a specified position by the stacker, the sheet processing method comprising: bringing the rotating alignment roller into contact with the sheet bundle held by the stacker when the sheet bundle on which the stapling process is performed is moved by the stacker in a direction retracting from the stapler; wherein information relating to a thickness of the sheet constituting the sheet bundle is acquired, and when the sheet bundle on which the stapling process is performed is moved by the stacker in the direction retracting from the stapler, as the thickness of the sheet becomes thick, a time in which the alignment roller is in contact with the sheet bundle held by the stacker is prolonged.