Prevention of stray light reflections in a raster output scanner (ROS) using an overfilled polygon design

摘要

In an optical scanning apparatus having an overfilled ROS polygon (24), stray reflection from facets (24R) adjacent the completely filled (illuminated) facet (24A) are prevented from affecting the scan line images by aligning the optical axes (40,50) of the pre-polygon and post-polygon optical components at an optimum angle Φ' so that the stray light reflections at the photoreceptor (32) occur only at non-image forming scan times (outside the image scan time). The optimum angle Φ' is expressed by the relationship Φ' = 2(Ω ± ½ ϑ) where Ω is given by the expression 360/X, X being the number of scanning facets, and ϑ being the scanning angle.