Patents by Inventor Yuugo Kumagai

Yuugo Kumagai 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).

  • Dry toner, dry developer and process for forming electrophotographic images
    Patent number: 4985328
    Abstract: A dry toner composition comprising (A) a binder resin, (B) a colorant and (C) charge control agents comprising a special metal complex of oxycarboxylic acid (C-1) and a special metal complex of azo compound (C-2) can provide high quality images without causing toner flying even after printed for a long period of time, and thus is useful for providing a dry developer and a process for forming images using said dry developer.
    Type: Grant
    Filed: September 21, 1989
    Date of Patent: January 15, 1991
    Assignee: Hitachi Chemical Co., Ltd.
    Inventors: Yuugo Kumagai, Ryouji Tan, Takashi Ikeda, Tetsuya Fujii, Chiaki Okada, Osamu Higashida, Hatuo Sugitani, Masato Fukasawa
  • Toner for developing electrostatic image comprising vinyl polymer having hydroxyl number of 50 to 350
    Patent number: 4950574
    Abstract: A toner comprising a vinyl polymer having a hydroxyl number of 50 to 350 and a glass transition point of 35.degree. to 100.degree. C., obtained from one or more monomers having a secondary hydroxyl group and, if necessary, one or more vinyl monomers copolymerizable with the vinyl monomer having a secondary hydroxyl group, is excellent in resistance to adhesion to non-rigid polyvinyl chloride and resistance to blocking under high humidity.
    Type: Grant
    Filed: February 4, 1985
    Date of Patent: August 21, 1990
    Assignee: Hitachi Chemical Company, Ltd.
    Inventors: Yuugo Kumagai, Isamu Moribe, Ikutoshi Shibuya
  • Electrophoto toner comprising imido group monomer unit in polymer
    Patent number: 4686166
    Abstract: A toner for developing latent electrostatic images comprising a copolymer having as an essential component a monomer unit derived from an imido group-containing unsaturated monomer of the formula: ##STR1## wherein R.sub.1, R.sub.2 and R.sub.3 are as defined in the specification, has excellent properties such as resistance to adhesion to plasticized polyvinyl chloride, high image density, resistance to fogging, etc.
    Type: Grant
    Filed: October 6, 1986
    Date of Patent: August 11, 1987
    Assignee: Hitachi Chemical Co.
    Inventors: Yuugo Kumagai, Isamu Moribe, Takayuki Saito, Toshiyuki Fujita, Akihiro Kobayashi