Patents by Inventor Hiroshi Yamasita

Hiroshi Yamasita 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: 6740460
    Abstract: A dry toner for developing an electrostatic image, including a toner binder containing a urea-modified polyester. The toner has a volume average particle diameter Dv of 3 to 10 &mgr;m and a number average particle diameter Dp such that the ratio Dv/Dp of the volume average particle diameter to the number average particle diameter ranges from 1.05 to 1.25.
    Type: Grant
    Filed: September 17, 2002
    Date of Patent: May 25, 2004
    Assignee: Ricoh Company, Ltd.
    Inventors: Masami Tomita, Shigeru Emoto, Hiroshi Yamasita, Tsunemi Sugiyama
  • Publication number: 20030113648
    Abstract: A dry toner for developing an electrostatic image, including a toner binder containing a urea-modified polyester. The toner has a volume average particle diameter Dv of 3 to 10 &mgr;m and a number average particle diameter Dp such that the ratio Dv/Dp of the volume average particle diameter to the number average particle diameter ranges from 1.05 to 1.25.
    Type: Application
    Filed: September 17, 2002
    Publication date: June 19, 2003
    Inventors: Masami Tomita, Shigeru Emoto, Hiroshi Yamasita, Tsunemi Sugiyama
  • Publication number: 20030022084
    Abstract: A dry toner including at least a modified polyester as a toner binder, wherein the modified polyester has a main peak in a molecular weight region of 1000 to 30000 in a molecular weight distribution as measured by GPC, contains 1 to 10% of a component having a molecular weight of at least 30000, and has an Mw/Mn ratio of not greater than 15.
    Type: Application
    Filed: March 18, 2002
    Publication date: January 30, 2003
    Inventors: Tsunemi Sugiyama, Shigeru Emoto, Hiroshi Yamasita, Masami Tomita, Kazuhito Watanabe, Chiaki Tanaka
  • Patent number: 6125257
    Abstract: The current methods and systems for cleaning residual ultra-fine spherical toner from an image forming surface discloses the application of aspherical toner to a cleaning blade. The aspherical toner is generally larger than the ultra-fine spherical toner which provides a superior image on an image-carrying medium. According to one preferred embodiment of the current invention, the aspherical black toner is placed in a predetermined area outside of a desired image area where the ultra-fine spherical toner in multiple colors is placed. The aspherical toner is transported to the cleaning blade before the multi-color toner reaches the cleaning blade. Since the aspherical toner applied at a contacting edge of the cleaning blade provide an effective seal or trap between the cleaning blade and the image forming surface, the ultra-fine spherical toner is effectively removed from the image forming surface.
    Type: Grant
    Filed: February 5, 1997
    Date of Patent: September 26, 2000
    Assignee: Ricoh Co., Ltd.
    Inventors: Takeyoshi Sekine, Hiroshi Yamasita, Hiroyuki Fushimi, Makoto Ohsaki, Kouta Fujimdri, Yasunori Kawaishi, Jun Okamoto
  • Patent number: 5648842
    Abstract: The current methods and systems for cleaning residual ultra-fine spherical toner from an image forming surface discloses the application of aspherical toner to a cleaning blade. The aspherical toner is generally larger than the ultra-fine spherical toner which provides a superior image on an image-carrying medium. According to one preferred embodiment of the current invention, the aspherical black toner is placed in a predetermined area outside of a desired image area where the ultra-fine spherical toner in multiple colors is placed. The aspherical toner is transported to the cleaning blade before the multi-color toner reaches the cleaning blade. Since the aspherical toner applied at a contacting edge of the cleaning blade provide an effective seal or trap between the cleaning blade and the image forming surface, the ultra-fine spherical toner is effectively removed from the image forming surface.
    Type: Grant
    Filed: January 16, 1996
    Date of Patent: July 15, 1997
    Assignee: Ricoh Company, Ltd.
    Inventors: Takeyoshi Sekine, Hiroshi Yamasita, Hiroyuki Fushimi, Makoto Ohsaki, Kouta Fujimdri, Yasunori Kawaishi, Jun Okamoto