Lexmark International, Inc.

Steven Alan Seng

Mark Edwin Kirtley Lund

Michael Wesley Brown

Eric Wayne Westerfield

An imaging device has a photoconductive drum with a surface that is charged and selectively discharged to create a latent electrostatic image of an image to-be-printed for attracting toner for transfer to a media. A memory of the imaging device stores energy density values for use by the laser beam that can be accessed by a controller according to a predetermined number of media imaged by the photoconductive drum. During imaging, the controller controls the laser beam based on the stored energy density values. The energy density of the laser beam is increased or decreased when the laser beam is scanned along the photoconductive drum.

Maintaining consistent darkness levels produced by a photoconductive drum during the life of the photoconductive drum

Methods are provided for an EP device such as a laser printer or copier, to compensate for variations in scanning rate. At intervals during a scanning process, actual scanning rate is measured and compared to a basal scanning rate of the EP device. Adjustments in the laser light source intensity are then implemented to preserve a predetermined image darkness notwithstanding variations in scanning rate, thereby preserving print quality. To implement the adjustments, a compensation factor is calculated based on a difference between the basal scanning rate of the device and the measured actual scanning rate. The steps of measuring an actual scanning rate, calculating a compensation factor, and adjusting laser operating intensity may be performed during a warming-up function at EP device at start-up, during a print job, or both. An EP device utilizing the method of the present invention is provided also.

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Lexington, KY, United States of America

Steven Alan Seng