Abstract: An imaging system is provided for scanning stationary objects in an object plane and projecting the image onto a moving flat photoreceptor in such a manner that the image moves in a direction opposite the photoreceptor movement. In a preferred embodiment, the scanning illumination elements comprise a modified dual rate mirror system where the second mirror is moving at less than 1/2 the speed of the scan mirror thereby causing a resultant increase in platen-to-lens distance. This increase is compensated for, and image precession obtained, by moving the lens and mirror assembly along the optical axis in a direction opposed to that of the photoreceptor.

Abstract: An optical imaging system for scanning a document moving through an exposure zone. The imaging system comprises optical components including a mirror arrangement and a projection assembly for projecting reflected document images onto a flat portion of a photoreceptor. The optical components are stationary in a first mode of operation wherein documents are stream fed past the exposure zone at the process speed. In a second mode of operation, wherein multiple copies are made of the same document, the optical components are moved in a defined relationship so that the image is projected onto the photoreceptor in a direction opposite to the direction of photoreceptor motion. This form of image projection is termed image precession and results in additional time being available to replace the document at the start of scan portion without reduction in copy reproduction rate.