INTENSITY CONTROL FOR RASTER OUTPUT SCANNERS
Original Publication Date: 1984-Feb-29
Included in the Prior Art Database: 2004-Apr-04
Xerox Disclosure Journal
Referring to Figure 1, Raster Output Scanners (ROS) suffer from intensity variations in the writing beam 3 which may degrade performance on the recording media such as photoreceptor 4 of a xerographic system. In particular, raster spot intensity decreases at both ends of scan in conventional overfilled polygon illumination as well as in facet tracking illumination. This fall-off of raster intensity may be a problem in attempting to faithfully reproduce the images scanned. Similarily, intensity non-uniformities caused by other ROS related components can occur from raster line to raster line due to differences in the facet reflectivity of polygon 5 or over groups of raster lines due for example to power degradation of laser 6, dirt collection on optical surfaces such as mirror 7, or loss of efficiency of modulator 8.