Patent ID: 7568686

Claim:
A sheet processing apparatus comprising: a processing tray to load a sheet bundle; a first conveying unit having a rotary shaft installed at least at an end on a downstream side in a direction to move the sheet bundle on the processing tray and drive to rotate via a first drive source and a drive unit and a roller installed on the rotary shaft to load and convey the sheet bundle and discharge the sheet bundle from the end on the downstream side and from the processing tray; a second conveying unit having a pair of pulleys having at least one of them installed rotatably on the rotary shaft on the downstream side driven to rotate via a second drive source and a drive unit, a belt stretched over the pair of pulleys, and an arm installed on the belt to hook an end of the sheet bundle on the processing tray, convey the sheet bundle together with the roller, and discharge the sheet bundle from the end on the downstream side and from the processing tray; and a controller to control the second conveying unit to synchronize the speed of the arm when moving along a straight portion of the belt with a rotational speed of the roller of the first conveying unit and change the speed when moving in a peripheral direction of the pulley on the downstream side among the pair of pulleys from the rotational speed of the roller.