Patents by Inventor Xu H. Feng

Xu H. Feng has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Dynamic developer bias control for use in an electrostatographic printing machine
    Patent number: 5402210
    Abstract: A method and apparatus for providing a novel dynamic developer bias control system adapted to determine an optimal developer bias during the processing of the lead edge of an input document. Loss of image density for images on the lead edge of a document is minimized by varying the developer bias relative to variations in an optical sensor voltage signal. In addition, background development in the body of the copy sheet is further prevented by maintaining a developer bias at an elevated level in response to a determination that the lamp voltage exceeds a maximum level and the optical sensor signal is less than a predetermined target value.
    Type: Grant
    Filed: October 22, 1993
    Date of Patent: March 28, 1995
    Assignee: Xerox Corporation
    Inventors: Lawrence M. Hart, Xu H. Feng, Ding Ya-Jun
  • Non-linear selectively variable copy contrast adjustment device
    Patent number: 5400122
    Abstract: An electrostatographic printing apparatus adapted to provide selectively variable copy contrast, including a movable control member and a system for providing non-linearly variable contrast control in response to selective displacement of the control member, the control member having non-linear sensitivity to selective displacement thereof such that the variable copy contrast does not have a linear relation to relative displacement of the control member.
    Type: Grant
    Filed: October 28, 1993
    Date of Patent: March 21, 1995
    Assignee: Xerox Corporation
    Inventors: Thomas F. Szlucha, Xu H. Feng, Ding Ya-Jun