START-OF-SCAN AND END-OF-SCAN OPTICAL ELEMENT FOR A RASTER OUTPUT SCANNER
Original Publication Date: 1992-Oct-31
Included in the Prior Art Database: 2004-Apr-06
Xerox Disclosure Journal
Figure 1 shows a scanning system for use with an electrophotographic printer in which disclosed start-of-scan and end-of-scan optical element 30 is disposed. Laser source 10 produces collimated laser beam 12 which is reflected from the facets of rotating polygon 14. Each facet of polygon 14 in turn deflects laser beam 12 to create an illuminated beam spot 16 on the pre-charged surface of photoreceptor 18. The system may further include additional optical elements such as focusing lenses 15. The periodic scanning of beam spot 16 across the moving photoreceptor 18 creates an array of scan lines 20. Optical element 30 elongated in the scan direction is adapted for the transmission of light therethrough in a direction transverse to the scan direction. Optical patterns 32 and 34 along a portion of optical element 30 in the scan direction include at least one surface for the non-transmission of light passing transverse to the scan direction. Areas 32 and 34 having optical patterns therein are most usefully placed at the areas along the scan direction corresponding to the end points of scan line 20.