Patents by Inventor Wing Sum Vincent Kwan

Wing Sum Vincent Kwan 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).

  • Hydrophobic treatment of pigments
    Patent number: 5922121
    Abstract: A surface derivatizing agent is allowed to contact an aqueous slurry of transition metal-containing pigment particles to increase the hydrophobicity of the surface of such particles. The modified pigment particles disperse easily in a wide variety of organic solvents, and provide stable, dispersions having a small mean pigment particle size and narrow particle size distribution.
    Type: Grant
    Filed: May 24, 1996
    Date of Patent: July 13, 1999
    Assignee: Videojet Systems International, Inc.
    Inventor: Wing Sum Vincent Kwan
  • Hydrophilic treatment of pigments
    Patent number: 5865885
    Abstract: A surface coordinating agent is allowed to contact an aqueous slurry of transition metal-containing pigment particles to increase the hydrophilicity of the surface of such particles. The modified pigment particles disperse easily in a wide variety of solvents, and provide stable, dispersions having a small mean pigment particle size and narrow particle size distribution.
    Type: Grant
    Filed: October 8, 1996
    Date of Patent: February 2, 1999
    Assignee: Videojet Systems International, Inc.
    Inventor: Wing Sum Vincent Kwan
  • Pigment dispersion
    Patent number: 5855661
    Abstract: A method for preparing modified pigment particles including contacting an aqueous slurry of metallo, mono and bi-dentate ligand pigment particles with a surface derivatizing agent having one or more phenolic moieties, a 1, 3-diketo moiety or a combination thereof.
    Type: Grant
    Filed: January 18, 1996
    Date of Patent: January 5, 1999
    Assignee: Videojet Systems International, Inc.
    Inventor: Wing Sum Vincent Kwan
  • Method for preparing magnetic ink and dry pigment particles used therefor
    Patent number: 5849074
    Abstract: A method for making magnetic ink compositions is disclosed. The magnetic particles used in the ink are prepared from an aqueous slurry. A surface derivatizing agent is added to the slurry to render the magnetic pigment particles hydrophobic. The particles then sink to the bottom of the slurry, and the bulk water is then removed. After air drying, dry magnetic pigment particles are provided. The particles will be hydrophobic, and thus will have superior resistance to water as compared to previously known magnetic pigment particles. Magnetic ink compositions are formulated from the magnetic particles.
    Type: Grant
    Filed: July 19, 1996
    Date of Patent: December 15, 1998
    Assignee: Videojet Systems International, Inc.
    Inventor: Wing Sum Vincent Kwan