Patent ID: 7688340

Claim:
A method for determining a minimum operational power level for operating a raster output scanner (ROS) laser in a color xerographic machine comprising: charging an image panel on a photoreceptor to a minimum photoreceptor charge level; exposing the image panel on the photoreceptor to a ROS laser operated at a first power level; measuring discharge voltages of the image panel on the photoreceptor after exposure to the ROS laser; continuing to charge the image panel on the photoreceptor to a minimum photoreceptor charge level, exposing the image panel on the photoreceptor to a ROS laser operated at a power level reduced from the power level previously used to operate the ROS laser for image panel exposure, and measuring the discharge voltages of the image panel on the photoreceptor until a difference between discharge voltages of the image panel at successive power levels for operating the ROS laser exceeds a maximum voltage change limit; interpolating a ROS power level at which the difference between discharge voltages reaches the maximum voltage change limit when the image panel on the photoreceptor is charged to the minimum photoreceptor charge level; charging an image panel on a photoreceptor to a maximum photoreceptor charge level; exposing the image panel on the photoreceptor to the ROS laser operated at a second power level that is greater than the first power level; measuring discharge voltages of the image panel on the photoreceptor after exposure to the ROS laser; continuing to charge the image panel on the photoreceptor to a maximum photoreceptor charge level, exposing the image panel on the photoreceptor to a ROS laser operated at a power level reduced from the power level previously used to operate the ROS laser for image panel exposure, and measuring the discharge voltages of the image panel on the photoreceptor until a difference between discharge voltages of the image panel at successive power levels for operating the ROS laser exceeds a maximum voltage change limit; interpolating a ROS power level at which the difference between discharge voltages reaches the maximum voltage change limit when the image panel on the photoreceptor is charged to the maximum photoreceptor charge level; calculating a linear relationship between the two interpolated ROS power levels; and establishing a ROS power lower limit for a photoreceptor charge level from the calculated linear relationship.