Output copy quality in a ROS electrophotographic printer is maintained by a method and apparatus designed to selectively vary the beam intensity level of a laser beam scan in response to changed conditions within the scanning or xerographic output subsystems. A test pattern video data input is periodically...http://www.google.com.au/patents/US5165074?utm_source=gb-gplus-sharePatent US5165074 - Means and method for controlling raster output scanner intensity
