Patents by Inventor Dirk W. Hertel

Dirk W. Hertel 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).

  • Method and apparatus for controlling the uniformity of print density of a thermal print head array
    Patent number: 7545401
    Abstract: A method for controlling the print density of individual heating elements of a thermal print head array determines respective energy values for each heating element in response to image pixel data to be printed, multiplies determined energy values by a respective predetermined correction factor for one or more respective heating elements for improving print density consistency between individual heating elements, and dithers adjusted energy values from the step of multiplying as a function of adjacent image pixels.
    Type: Grant
    Filed: October 4, 2007
    Date of Patent: June 9, 2009
    Assignee: Polaroid Corporation
    Inventors: Brian D. Busch, Dirk W. Hertel, Leif D. Hille, Suhail S. Saquib
  • Method and apparatus for controlling the uniformity of print density of a thermal print head array
    Patent number: 7369145
    Abstract: A method for controlling the print density of individual heating elements of a thermal print head array determines respective energy values for each heating element in response to image pixel data to be printed, multiplies determined energy values by a respective predetermined correction factor for one or more respective heating elements for improving print density consistency between individual heating elements, and dithers adjusted energy values from the step of multiplying as a function of adjacent image pixels.
    Type: Grant
    Filed: January 10, 2005
    Date of Patent: May 6, 2008
    Assignee: Polaroid Corporation
    Inventors: Brian D. Busch, Dirk W. Hertel, Leif D. Hille, Suhail S. Saquib