Patents Assigned to Paul C. Fisher
  • Patent number: 4789399
    Abstract: A pressurized roller pen includes a thixotropic viscoelastic ink that is a gel at rest, but becomes a thin liquid under the shearing action of the pen's revolving ball-point. This ink includes a polyacrylic resin polymer, at least one highly polar solvent, at least one solvent of low or medium polarity, and colloidal silica, together with pigments, dyes, surfactants and/or pH modifiers.
    Type: Grant
    Filed: October 20, 1986
    Date of Patent: December 6, 1988
    Assignee: Paul C. Fisher
    Inventors: Raymond S. Williams, Paul C. Fisher
  • Patent number: 4419464
    Abstract: An erasable ink for use in a ball point pen, particularly in a pressurized cartridge, is a fluid comprising at least 10% w of polyvinyl acetate or a copolymer of ethylene and vinyl acetate, and at least 10% w trichloroethylene. The ink preferably also contains at least 5% w of a solvent boiling in the range of 180.degree.-250.degree. C., a plasticizer boiling above 270.degree. C., a colorant, and a tackifier.
    Type: Grant
    Filed: July 29, 1982
    Date of Patent: December 6, 1983
    Assignee: Paul C. Fisher
    Inventors: Raymond S. Williams, Paul C. Fisher
  • Patent number: 4367966
    Abstract: An erasable ink for use in a ball point pen, particularly in a pressurized cartridge, is a fluid comprising at least 10% w of polyvinyl acetate or a copolymer of ethylene and vinyl acetate, and at least 10% w trichloroethylene. The ink preferably also contains at least 5% w of a solvent boiling in the range of 180.degree.-250.degree. C., a plasticizer boiling above 270.degree. C., a colorant, and a tackifier.
    Type: Grant
    Filed: November 12, 1981
    Date of Patent: January 11, 1983
    Assignee: Paul C. Fisher
    Inventors: Raymond S. Williams, Paul C. Fisher