Patents by Inventor Gunnar Mattson

Gunnar Mattson 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).

  • Toner particles for electrophotographic copying and processes for their preparation
    Patent number: 4923776
    Abstract: Toner particles for electrophotographic copying and electrostatic printing consist of pigmented thermoplastic base particles having the surface covered with a thermoplastic fine-grained polymerizate. The base particles are prepared by suspension polymerization and the fine-grained polymerizate originates from a latex prepared by emulsion or microsuspension polymerization. One method of preparing the toner consists of bringing an aqueous dispersion of the base particles into contact with a latex of the fine-grained polymerizate. The temperature is raised so that the fine-grained particles adhere to the surface of the base particles. A protective colloid system can be present and the particles can have charges of opposite character. In another method the preparation of the toner particles comprises suspension polymerization of monomer for formation of the base particles in the presence of an already prepared latex whereby the latex particles have higher hydrophilicity than the polymer in the base particle.
    Type: Grant
    Filed: October 26, 1988
    Date of Patent: May 8, 1990
    Assignee: Casco Nobel AB
    Inventors: Bertil Hedvall, Gunnar Mattson, Sten Porrvik, Goran Sundstrom
  • Toner particles for electrophotographic copying and processes for their preparation
    Patent number: 4794065
    Abstract: Toner particles for electrophotographic copying and electrostatic printing consist of pigmented thermoplastic base particles having the surface covered with a thermoplastic fine-grained polymerizate. The base particles are prepared by suspension polymerization and the fine-grained polymerizate originates from a latex prepared by emulsion or microsuspension polymerization. One method of preparing the toner consists of bringing an aqueous dispersion of the base particles into contact with a latex of the fine-grained polymerizate. The temperature is raised so that the fine-grained particles adhere to the surface of the base particle. A protective colloid system can be present and/or the particles can have charges of opposite character. In another method the preparation of the toner particles comprises suspension polymerization of monomer for formation of the base particles in the presence of an already prepared latex whereby the latex particles have higher hydrophility than the polymer in the base particle.
    Type: Grant
    Filed: April 20, 1987
    Date of Patent: December 27, 1988
    Assignee: Casco Nobel AB
    Inventors: Bertil Hedvall, Gunnar Mattson, Sten Porrvik, Goran Sundstrom