Patent ID: 7564475
Filing Date: 2009-07-21
Classification: B41J,H04N

Abstract:
1. A method comprising: (a) writing a test pattern using multiple image beams in a non image zone at set time intervals; (b) sensing said test pattern; (c) determining a profile of each beam from said multiple image beams; (d) determining a minimum reflectance of said profile from said test pattern of each said beam thereby providing an exposure of each respective said beam; (e) determining a centroid of a profile from said test pattern of each said beam thereby providing a position of each respective said beam; (f) determining at least one of frequency, amplitude and phase of banding, which is inherent in a printing device, based on the sensed test pattern; (g) combining a plurality of groups of image beams intensity changes wherein each group is separated by a set displacement; (h) determining a banding profile from said group beam intensities; (i) determining at least one banding compensation metric based at least on one of the determined frequency, amplitude and phase of banding; and, (j) adjusting beam intensity changes based on the determined banding compensation metric to compensate the banding inherent in the printing device.