Patents by Inventor Toyoko Imai

Toyoko Imai 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).

  • Process for producing toner through suspension polymerization
    Patent number: 5427885
    Abstract: A process for producing a toner for developing an electrostatic image, including the steps of: adding to an aqueous dispersion medium a polymerizable monomer composition comprising at least a polymerizable monomer and a colorant uniformly dissolved or dispersed in the polymerizable monomer, wherein the aqueous dispersion medium containing as a dispersion stabilizer a hardly water-soluble metal hydroxide colloid formed by a reaction of a water-soluble polyvalent metal salt with an alkali metal hydroxide in an aqueous phase; and subjecting the polymerizable monomer composition to suspension polymerization, thereby to produce particles having a volume-average particle size in the range of from 2 to 20 .mu.m and a particle size distribution (a ratio of volume-average particle size/number-average particle size) of not more than 1.6.
    Type: Grant
    Filed: March 28, 1994
    Date of Patent: June 27, 1995
    Assignee: Nippon Zeon Co., Ltd.
    Inventors: Nobuyasu Ota, Toyoko Imai, Jun Saito, Tokudai Ogawa