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LEAD EDGE SENSOR Disclosure Number: IPCOM000024678D
Original Publication Date: 1981-Aug-31
Included in the Prior Art Database: 2004-Apr-02

Publishing Venue

Xerox Disclosure Journal


An edge or position sensor design capable of detecting the leading edge of a moving document to within + 5 millimeters. In the accompanying figure the sensor 1 comprises a photo tTansistor 2 fixed with respect to a plastic housing having a number of segments labeled A-D. An optically transparent belt 3 periodically moves documents 4 past the sensor 1 which is used to detect the passage of each document past a 5 mil width optical window 6. A light source 7 is positioned on a side of the belt 3 removed from the sensor 1 so the documents disrupt the light passing to the sensor and accordingly reduce conduction in the photo transistor