Sorter and image forming apparatus

摘要

A sheet sorting apparatus includes a plurality of trays for accommodating sheets; a helical cam device, engageable with a cam follower for moving the plurality of trays; a cam driving device for driving the helical cam device; a sheet set processing device movable between processing position and a retracted position where the processing device doe snot interfere with the plurality of trays; a reversible driving device for advancing or retracting the sheet set processing device; and a controlling device for controlling the driving device; wherein a cam surface of the helical cam is constituted of substantially horizontal portions and slanted portions; and the cam driving device and the driving device are controlled by the controlling device, in such a manner that the sheet set processing device starts to enter a processing position when the cam follower shifts from the slanted portions to the horizontal portions, and the entering operation ends by the time the cam follower reaches the middle portion of the horizontal portion, and that the cam driving device is deactivated when the cam follower is substantially at a middle portion of the horizontal portions, and after sheet set processing, the cam driving device and the driving device are actuated, and the sheet set processing device is retracted from a moving path region of the tray by the time the cam follower passes through the remaining portion of the horizontal portions.