Procedure and device for cross-registration on light-receiving tapes

摘要

A method and apparatus for transverse registration of image exposures on photoreceptive belts (12) subject to lateral deviation from linear travel in which targets (T1, T2, T3), corresponding in location to the image areas (l1, l2, l3) to be exposed, are used for the detection of lateral belt displacement and to control the transverse location of exposure scan. The targets are of a pattern defining a reference line and a line inclined with respect to the direction (18) of belt travel so that the duration of time between passage of the target lines with respect to a spacially fixed sensing axis in a sensor (36) will vary with lateral displacement of the belt. The targets may assume a variety of specific patterns and the invention is applicable to single and multi-pass image exposure systems as well as to both modulated laser and light emitting diode types of exposure devices. IMAGE