Permanent photoreceptor registration marking and method

Cross-reference is made to a commonly assigned co-pending U.S. application Ser. No. 09/692,236, filed Oct. 20, 2000 by Martin E. Hoover et al, entitled "Two Dimensional Surface Motion Sensing System Using Registration Marks and Linear Array Sensor". Xerographic printers may be provided with a photoreceptor belt manufactured so that transparent permanent optical registration marks are formed in defined selected minor areas of the belt without physically weakening the belt, as is the case with belt holes. These permanent registration marks are sufficiently transparent for a conventional belt holes sensor to optically detect them by illumination through those transparent areas of the photoreceptor. The photoreceptor is preferably a plural layer organic photoreceptor with an internal optically opaque metallic ground plane layer, and the optical registration marks are formed by oxidizing defined areas thereof. This may be accomplished by the simultaneous selective application of illumination to these selected minor areas of the photoreceptor, while adjacent areas of the photoreceptor are not illuminated, plus the application of electrical current from a voltage source applied through the belt in those areas.