PROXIMITY SWITCH FOR COPY SHEET TRAY
Original Publication Date: 1989-Apr-30
Included in the Prior Art Database: 2004-Apr-04
Xerox Disclosure Journal
In an electrophotographic printing machine, it is frequently necessary to determine the absence or presence of copy sheets in a tray. A capacitive sensing switch may be mounted on the underside of the tray for detecting the presence or absence of copy sheets. The capacitive sensing switch replaces an optical sensor. The capacitance type of proximity sensing switch can detect copies through the plastic tray material without an opening an.1 the tray is sealed from dust. A switch of this type is insensitive to ambient light and contamination, and has higher reliability than optical sensors.