Browse Prior Art Database

Original Publication Date: 1981-Feb-28
Included in the Prior Art Database: 2004-Apr-02

Publishing Venue

Xerox Disclosure Journal


In electrophotographic copiers having moving original documents or moving optical systems, some form of mechanical scanning device is used. In such scanning devices, some form of energy absorbing device is frequently used at the end of the rescan cycle. This disclosure describes a concept for recovering the energy of the rescan motion, storing it for later use, then delivering it back to the scanning system in a controlled way such that dynamic overshoot at the beginning of the scan is minimized. A preferred mechanism for accomplishing this objective is shown in Figure 1. Three stages of the action of this mechanism are shown: approaching the end of rescan in Figure 1A; the "homel' or rest position between scans in 18; and the start of scan in 1C. Scan carriage 1 has surface 2 as the end point of its travel to the "home" position. The carriage carries pin 3 which engages toggle mechanism 4 consisting of spring 5 and fixed pins 6, 7 and 8, respectively. As "homet1 position is approached in Figure lA, pin 3 engages the toggle mechanism and extends spring 5, thereby storing mechanical energy and reducing the carriage rescan velocity, shown as arrow V to zero. At the "home" position in Figure lB, the carriage is at rest, and the spring stores the potential energy absorbed from the rescan. When the next scan cycle begins, as shown in Figure lC, the toggle action begins, and the force exerted by the spring-drives toggle, on the carriage via pin 3 accelerates it to scan velocity V without producing dynamic overshoot. Although not illustrated, the concept of ths disclosure may be extended to other types of mechanisms involving energy storage means such as movable weights and com-pressed air.