Patents by Inventor Yohichiro Watanabe

Yohichiro Watanabe 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, DEVELOPER, AND IMAGE FORMING APPARATUS
    Publication number: 20100021209
    Abstract: A toner produced by dissolving or dispersing toner components comprising a binder resin, a colorant, and a charge controlling agent in an organic solvent to prepare a toner components liquid, forming liquid droplets of the toner components liquid in a gas phase, and solidifying the liquid droplets into toner particles of the toner. The charge controlling agent includes a polycondensation reaction product of a phenol with an aldehyde.
    Type: Application
    Filed: July 15, 2009
    Publication date: January 28, 2010
    Inventors: Yohichiro WATANABE, Kazumi Suzuki, Takahiro Honda, Shinji Ohtani, Yoshihiro Norikane
  • Color toner, method for manufacturing the toner, and image forming apparatus and method using the toner
    Patent number: 7049037
    Abstract: A color toner composition including at least toner particles including at least a binder resin; a colorant and a release agent dispersed in the binder resin; and a titania as an external additive, wherein the colorant has an average dispersion particle diameter not greater than 0.5 ?m; the release agent and the binder resin are insoluble to each other; the toner particles satisfy the relationship: 0.05?Dw/D4?0.4, wherein Dw represents an average dispersion particle diameter of the release agent and D4 represents a weight-average particle diameter of the toner particles; and the titania has a segregation rate of from 0.5 to 5%.
    Type: Grant
    Filed: August 6, 2004
    Date of Patent: May 23, 2006
    Assignee: Ricoh Company, Ltd.
    Inventors: Kohki Katoh, Masanori Suzuki, Yohichiro Watanabe, Masahide Yamashita, Akihiro Kotsugai, Toyoshi Sawada, Keiko Shiraishi
  • Color toner, method for manufacturing the toner, and image forming apparatus and method using the toner
    Patent number: 6852459
    Abstract: A color toner composition including at least toner particles including at least a binder resin; a colorant and a release agent dispersed in the binder resin; and a titania as an external additive, wherein the colorant has an average dispersion particle diameter not greater than 0.5 ?m; the release agent and the binder resin are insoluble to each other; the toner particles satisfy the relationship: 0.05?Dw/D4?0.4, wherein Dw represents an average dispersion particle diameter of the release agent and D4 represents a weight-average particle diameter of the toner particles; and the titania has a segregation rate of from 0.5 to 5%.
    Type: Grant
    Filed: February 22, 2002
    Date of Patent: February 8, 2005
    Assignee: Ricoh Company, Ltd.
    Inventors: Kohki Katoh, Masanori Suzuki, Yohichiro Watanabe, Masahide Yamashita, Akihiro Kotsugai, Toyoshi Sawada, Keiko Shiraishi
  • Color toner, method for manufacturing the toner, and image forming apparatus and method using the toner
    Publication number: 20050008962
    Abstract: A color toner composition including at least toner particles including at least a binder resin; a colorant and a release agent dispersed in the binder resin; and a titania as an external additive, wherein the colorant has an average dispersion particle diameter not greater than 0.5 ?m; the release agent and the binder resin are insoluble to each other; the toner particles satisfy the relationship: 0.05?Dw/D4? 0.4, wherein Dw represents an average dispersion particle diameter of the release agent and D4 represents a weight-average particle diameter of the toner particles; and the titania has a segregation rate of from 0.5 to 5%.
    Type: Application
    Filed: August 6, 2004
    Publication date: January 13, 2005
    Inventors: Kohki Katoh, Masanori Suzuki, Yohichiro Watanabe, Masahide Yamashita, Akihiro Kotsugai, Toyoshi Sawada, Keiko Shiraishi
  • Color toner, method for manufacturing the toner, and image forming apparatus and method using the toner
    Publication number: 20030096183
    Abstract: A color toner composition including at least toner particles including at least a binder resin; a colorant and a release agent dispersed in the binder resin; and a titania as an external additive, wherein the colorant has an average dispersion particle diameter not greater than 0.5 &mgr;m; the release agent and the binder resin are insoluble to each other; the toner particles satisfy the relationship: 0.05≦Dw/D4≦0.4, wherein Dw represents an average dispersion particle diameter of the release agent and D4 represents a weight-average particle diameter of the toner particles; and the titania has a segregation rate of from 0.5 to 5%.
    Type: Application
    Filed: February 22, 2002
    Publication date: May 22, 2003
    Inventors: Kohki Katoh, Masanori Suzuki, Yohichiro Watanabe, Masahide Yamashita, Akihiro Kotsugai, Toyoshi Sawada, Keiko Shiraishi
  • Toner for use in electrostatic development
    Patent number: 5429901
    Abstract: A toner for use in electrostatic development is composed of toner particles, each toner particle being composed of a core particle containing a thermoplastic resin and a coloring agent; a releasing agent in the form of particles, which substantially cover the entire surface of the core particle; and a chargeable resin which covers at least part of the releasing agent.
    Type: Grant
    Filed: October 18, 1993
    Date of Patent: July 4, 1995
    Assignee: Ricoh Company, Ltd.
    Inventors: Kenkichi Muto, Yohichiro Watanabe, Akihiro Kotsugai