Field Limiter for Optical Wand
Original Publication Date: 1987-Feb-01
Included in the Prior Art Database: 2005-Jan-31
The output copy bin of a xerographic copier includes a vertically movable table upon which output copy sheets are stacked. The vertical height of the table is controlled by an optical wand and a servo motor. The optical wand comprises a light source located on one side of the table and a photocell located on the other side of the table. The photocell's field of view of the light source is restricted and controlled by a bundle of hollow pipes, thereby to reduce the effect of room ambient light on the photocell. Fig. 1 is a top view of copy-stacking table 10. Output copy paper moves in the direction of arrow 11 as it exits the copier (not shown) and enters the table area. An infrared light-emitting diode (LED) 12 is mounted to project a generally horizontal beam of light across the table, toward phototransistor 13.