A SERVO SYSTEM FOR MAINTAINING CONSTANT TENSION ON A WEB
Original Publication Date: 1978-Feb-28
Included in the Prior Art Database: 2004-Mar-31
Xerox Disclosure Journal
Apparatus for maintaining constant tension on a web 12 during movement thereof, e.g., during positioning original documents in an exposure station 14 of a reproduction machine. The web is coupled between a take up reel 137' and a supply reel 137, with each reel being driven by an electric motor. The two motors are energized by a signal from the same source 200, except that the signal D applied to the supply reel motor is the derivative of that signal VP applied to the take up reel motor. In such manner, the supply reel 137 is energized during periods of acceleration or deceleration of the web 12 thereby maintaining constant tension on the web during positioning.