BELT TRACKING SYSTEM
Original Publication Date: 1982-Feb-28
Included in the Prior Art Database: 2004-Apr-03
Xerox Disclosure Journal
In an electrophographic printing machine, the photoconductive belt is supported by a plurality of spaced rollers. Inasmuch as neither the rollers nor belt are perfect, the belt tends to move in a lateral direction away from the pre-determined path of travel. A steering roller is frequently employed to restore the belt to the desired path of travel. As shown in the drawing, the belt 10 passes over steering roller 12 which is mounted rotatably on frame 14. Positioning springs 16 and 18 maintain frame 14 in the desired position. As the belt moves from the desired path of travel, the edge thereof blocks airflow between opposed nozzles 20 and 22 of sen-sor 24. This produces a change in pressure resulting in a flapper valve restricting pressure to either bellows 26 and 28 while maintaining pressure in the other bellows so as to tilt roller 12. This restores belt 10 to the pre-selected path of travel.