Patents by Inventor Yoshinobu Joh

Yoshinobu Joh 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).

  • Patent number: 5500318
    Abstract: A toner for developing an electrostatic image is constituted by a binder resin and a colorant The binder resin is characterized by containing at least 20 wt. % of an extraction residue after 6 hours of extraction and below 20 wt. % of an extraction residue after 72 hours of extraction respectively by Soxhlet extraction with tetrahydrofuran. The toner shows a dynamic modulus and a loss modulus, respectively at 200.degree. C. and 0.1 Hz, which are substantially unchanging with time. The properties provide the toner with a harmonization of anti-offset characteristic and fixability as well as stable viscoelasticity under heating.
    Type: Grant
    Filed: June 27, 1994
    Date of Patent: March 19, 1996
    Assignee: Canon Kabushiki Kaisha
    Inventors: Hirohide Tanikawa, Masaki Uchiyama, Yoshinobu Joh, Yasutaka Akashi, Masaaki Taya, Makoto Unno
  • Patent number: 5330871
    Abstract: A toner for developing an electrostatic image is constituted by a binder resin and a colorant. The binder resin is characterized by containing at least 20 wt. % of an extraction residue after 6 hours of extraction and below 20 wt. % of an extraction residue after 72 hours of extraction respectively by Soxhlet extraction with tetrahydrofuran. The toner shows a dynamic modulus and a loss modulus, respectively at 200.degree. C. and 0.1 Hz, which are substantially unchanging with time. The properties provide the toner with a harmonization of anti-offset characteristic and fixability as well as stable viscoelasticity under heating.
    Type: Grant
    Filed: November 26, 1991
    Date of Patent: July 19, 1994
    Assignee: Canon Kabushiki Kaisha
    Inventors: Hirohide Tanikawa, Masaki Uchiyama, Yoshinobu Joh, Yasutaka Akashi, Masaaki Taya, Makoto Unno
  • Patent number: 5268248
    Abstract: A toner for developing an electrostatic image is provided as a pulverized mixture including a binder resin and a colorant. The binder resin is characterized by a molecular weight distribution on a GPC chromatogram of its tetrahydrofuran (THF)-soluble resin content including below 15% of a resin component in a molecular weight region of at most 5000 and at least 5 wt. % of a resin component in a molecular weight region of at least 5.times.10.sup.6 and showing a main peak in a molecular weight region of 5000 to 5.times.10.sup.6. The THF-soluble resin component in the molecular weight region of at least 5.times.10.sup.6 is extremely enriched during a melt-kneading step during the toner production, so as to effectively prevent toner flowout from a member for cleaning a fixing roller.
    Type: Grant
    Filed: November 26, 1991
    Date of Patent: December 7, 1993
    Assignee: Canon Kabushiki Kaisha
    Inventors: Hirohide Tanikawa, Masaki Uchiyama, Yoshinobu Joh, Yasutaka Akashi, Masaaki Taya, Makoto Unno, Kazuyoshi Hagiwara