Patents by Inventor John C. Dunfield

John C. Dunfield 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).

  • Patent number: 4668112
    Abstract: An improved serial impact printer designed to substantially reduce impact noise generation during the printing operation. The printer includes a print tip relatively movable with respect to a deformable platen, with a print element, a marking ribbon and an image receptor sheet interposed between the print tip and the platen which are urged together during a controlled contact period. Movement is subject to control by a kinetic drive mechanism which applies a first force for moving the print tip relative to the platen, prior to the initiation of the contact period, for closing the gap therebetween and then applies a second force for accelerating the print tip relative to the platen, subsequent to the initiation of the contact period, for causing the print tip to deform the platen.
    Type: Grant
    Filed: July 2, 1985
    Date of Patent: May 26, 1987
    Assignee: Xerox Corporation
    Inventors: Andrew Gabor, John C. Dunfield
  • Patent number: 4538930
    Abstract: A circuit for controlling the hammer velocity of an impact printer is described. A velocity sensor generates a signal which is a function of hammer position. This is compared to a reference voltage, and a drive pulse is generated if a velocity correction is needed. The sensor can be located at the backstop and used to control the hammer velocity toward zero as the position nears the backstop. If the sensor is located at the backstop, the sensor output will remain constant for following velocity as its position approaches the backstop, allowing a constant reference voltage. A table look-up can be inserted in the circuit to supply corrections, for a sensor that does not have a position dependent velocity output.
    Type: Grant
    Filed: September 24, 1984
    Date of Patent: September 3, 1985
    Assignee: Xerox Corporation
    Inventor: John C. Dunfield