Patents by Inventor George R. Hsu

George R. Hsu 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).

  • Polymer coated carrier particles for electrophotographic developers
    Patent number: 6245474
    Abstract: A coated carrier having a core particle coated with a mixture of an electronegative insulating polymer comprising a polyvinylidenefluoride polymer or copolymer and an electropositive conductive polymer comprising a polymethyl methacrylate polymer or copolymer with a conductive material dispersed therein is made by powder coating. The coated carrier has unique properties, including a conductivity of from 1.1×10−14 to 1.0×10−8 mho-cm−1, a triboelectric charging value of from 12 to 20 and an average particle diameter of from 65 to 75, rendering the coated carrier ideal for use in a developer to be used in a magnetic brush type development apparatus.
    Type: Grant
    Filed: March 7, 2000
    Date of Patent: June 12, 2001
    Assignee: Xerox Corporation
    Inventors: George R. Hsu, Scott M. Silence, Lynne M. Tatar, Bernard A. Kelly, Pinyen Lin
  • Environmentally friendly ferrite carrier core, and developer containing same
    Patent number: 6143456
    Abstract: A carrier core for use in an electrostatographic developer composition is a ferrite substantially free of copper and zinc. By being substantially free of copper and zinc, the carrier core is environmentally friendly and eliminates the need for use of conventional copper zinc carrier cores which must be handled as hazardous waste. Developer compositions employing the ferrite carrier core possess suitable properties.
    Type: Grant
    Filed: November 24, 1999
    Date of Patent: November 7, 2000
    Assignee: Xerox Corporation
    Inventors: Scott M. Silence, George R. Hsu, Brian E. Moore, Morris M. Deyoung, Jr.
  • Imaging with developer compositions with coated carrier particles
    Patent number: 5213936
    Abstract: A carrier composition comprised of a core with a coating thereover comprised of a mixture of first and second polymers that are not in close proximity thereto in the triboelectric series.
    Type: Grant
    Filed: December 17, 1990
    Date of Patent: May 25, 1993
    Assignee: Xerox Corporation
    Inventors: John A. Creatura, George R. Hsu
  • Electrophotographic coated carrier particles and methods thereof
    Patent number: 5015550
    Abstract: Disclosed is a carrier and developer composition, and a process for the preparation of carrier particles with substantially stable conductivity parameters which comprises (1) providing carrier cores and a polymer mixture, (2) dry mixing the cores and the polymer mixture, (3) heating the carrier core particles and polymer mixture, whereby the polymer mixture melts and fuses to the carrier core particles; and (4) thereafter cooling the resulting coated carrier particles.
    Type: Grant
    Filed: March 12, 1990
    Date of Patent: May 14, 1991
    Assignee: Xerox Corporation
    Inventors: John A. Creatura, George R. Hsu
  • Developer compositions with coated carrier particles
    Patent number: 5002846
    Abstract: A carrier composition comprised of a core with a coating thereover comprised of a mixture of first and second polymers that are not in close proximity thereto in the triboelectric series.
    Type: Grant
    Filed: March 12, 1990
    Date of Patent: March 26, 1991
    Assignee: Xerox Corporation
    Inventors: John A. Creatura, George R. Hsu
  • Polymer coated carrier particles for electrophotographic developers
    Patent number: 4937166
    Abstract: A carrier composition comprised of a core with a coating thereover comprised of a mixture of first and second polymers that are not in close proximity thereto in the triboelectric series.
    Type: Grant
    Filed: December 22, 1987
    Date of Patent: June 26, 1990
    Assignee: Xerox Corporation
    Inventors: John A. Creatura, George R. Hsu
  • Electrophotographic carrier particles coated with polymer mixture
    Patent number: 4935326
    Abstract: Disclosed is a carrier and developer composition, and a process for the preparation of carrier particles with substantially stable conductivity parameters which comprises (1) providing carrier cores and a polymer mixture; (2) dry mixing the cores and the polymer mixture; (3) heating the carrier core particles and polymer mixture, whereby the polymer mixture melts and fuses to the carrier core particles; and (4) thereafter cooling the resulting coated carrier particles.
    Type: Grant
    Filed: December 22, 1987
    Date of Patent: June 19, 1990
    Assignee: Xerox Corporation
    Inventors: John A. Creatura, George R. Hsu
  • Toner compositions
    Patent number: H1889
    Abstract: A toner comprised of resin, colorant, grinding compound, and wax.
    Type: Grant
    Filed: October 12, 1999
    Date of Patent: October 3, 2000
    Assignee: Xerox Corporation
    Inventors: Pinyen Lin, George R. Hsu