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Cheng-Lun Chen

George Tsu-Chih Chiu

Systems and methods for reducing banding artifact in electrophotographic devices are provided. One such electrophotographic device uses a closed loop controller that receives a feedback signal from an encoder connected to the OPC drum to improve the rotational velocity control of the drum. The encoder provides the rotational position or angular velocity of the drum to the closed loop controller as the feedback signal. Optionally, the electrophotographic device uses a closed loop controller that incorporates a model of the human visual system, such as the human contrast sensitivity function, to help reduce noticeable banding artifacts. The human contrast sensitivity function incorporated into the primary control loop helps filter out low frequency and non-periodic drum rotational velocity fluctuations in producing banding artifacts. The electrophotographic device may also include a repetitive controller in a secondary control loop to help reduce the effect of periodic drum rotational velocity fluctuations in producing banding artifacts. Methods and other systems also are provided.

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Lafayette, IN, United States of America

Cheng-Lun Chen