Constant velocity optical scanning system

Abstract

A compact mechanical linkage apparatus is disclosed to drive an optical scanning device underneath and parallel to a stationary transparent platen of a reproduction machine. The scanning device includes a carriage having an optical lens assembly. The carriage is adapted to move relative to the machine frame and on guide means for guiding the carriage along a path of travel parallel to the platen whereby successive incremental regions of the document or other object on the platen are scanned and the incremental light image formed by the scanning means are directed to the image receiving member. The carriage is driven along its scanning length by a multiple link mechanism having an input link adapted for full revolution at a constant speed and a one of its links slidably connected to the carriage for imparting thereto a straight line motion at constant speed. The imparted motion includes a forward direction from a start of scan position and an automatic return to the start of scan position after the scan length has been completed. A drive means for imparting a constant angular speed to the input link of the multiple link mechanism provides motivation for the carriage along its scanning distance without the need for cams, clutches, cables or pulleys and the carriage velocity is maintained within about 2% velocity accuracy.

Dependencies are inferred from the claim text.