Patent ID: 8565628

Claim:
A method of compensating for non-uniformity in an electrophotographic printer, comprising: providing the electrophotographic printer with a rotatable imaging component having an intentional periodic variation; forming a test patch by depositing toner on a test surface using the rotatable imaging component, the test patch having a length; measuring the respective densities of a plurality of points along the length of the test patch using a density sensor; using a processor to automatically detect, using the measured densities, respective angular positions of the intentional periodic variation in the test patch and respective amounts of an unintentional periodic variation in the test patch at one or more of the plurality of points; using the processor to automatically produce a non-uniformity map that relates the detected angular positions with the detected amounts at one or more of the plurality of points receiving an image signal representing a print image to be deposited on a receiver by the printer, the image signal including a plurality of regions arranged around the rotatable imaging component; rotating the rotatable imaging component and, for each successive region in the image signal: determining a region angular position of the intentional variation in the region; using the produced non-uniformity map to determine a correction value corresponding to the determined region angular position; automatically adjusting the image data of the region with the correction value using the processor; and depositing toner corresponding to the adjusted image data of the region on the receiver using the rotatable imaging component.