Patents by Inventor Ryouji Tan

Ryouji Tan 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