DOCUMENT POSITION SENSOR
Original Publication Date: 1981-Aug-31
Included in the Prior Art Database: 2004-Apr-02
Xerox Disclosure Journal
AbstractThis is a sensor for the approach or registration of the lead edge of an original document sheet 1 to the registration fingers or edge 2. The registration edge 2 may be fixed or pivotable away from the transparent copying platen 3 of a copier.
XEROX DISCLOSURE JOURNAL
DOCUMENT POSITION SENSOR 271/258 C1. US. Proposed Denis J. Stemmle Classification
Int. CI. B65H 7/02
This is a sensor for the approach or registration of the lead edge of an original document sheet 1 to the registration fingers or edge 2. The registration edge 2 may be fixed or pivotable away from the transparent copying platen 3 of a copier.
A light source 4 broadly illuminates this area. If no document is present most of this light passes through the platen and is absorbed by a dark patch 5 inside the copier.
If a document is present in a specific portion of the illuminated area to be sensed, it is "seen" by a photodetector 6 located inside the registration edge or finger
2. A tunnel aperture 7 to this sensor 6 restricts its sensing to a narrow, precise, area for accurate document position detection. The platen 3 may have an anti- reflective coating on its upper surface to increase the contrast between it and a document.
Volume 6 Number 4 July/August 1981 185
DOCUMENT POSTION SENSOR (Cont'd)
As a further feature, the lower portion 8 of the finger may be transparent and overlayed by a white or reflective layer 9 to eliminate edge effects by exposing the copier photoreceptor at the document edge with light reflected from this layer 9 during exposure of the document 1 by the regular copier illumination system (not shown) under the platen.
XEROX 186 DISCLOSURE JOURNAL