Patents by Inventor Takeaki Ohuchi

Takeaki Ohuchi 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: 6103439
    Abstract: In toner 1 containing a binder resin 2, wax particles 3 and a coloring agent, the wax particles 3 are designed so that the ratio of major axis/minor axis is set in the range of 1.4 to 4.0 and so that the major axis L is not more than 6.0 .mu.m. Moreover, the melt index of the binder resin ranges from 5.0 to 11.0, and the dielectric loss tangent (tan .delta.) is not more than 5.0. This arrangement prevents the wax particles 3 inside the toner 1 or at the toner 1 surface layer from exposing to or sticking out of the toner 1 surface, thereby making it possible to provide a superior offset-reducing property during the fixing process and electrophotographing toner that can reduce wax contamination on the surface of the toner-bearing body.
    Type: Grant
    Filed: April 15, 1998
    Date of Patent: August 15, 2000
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Satoshi Ogawa, Hitoshi Nagahama, Yasuharu Morinishi, Tatsuo Imafuku, Takeaki Ohuchi, Toshihisa Ishida, Tadashi Nakamura
  • Patent number: 5981129
    Abstract: An electrophotographic toner is made up of toner particles composed of irregularly-shaped core particles made chiefly of binder resin, and surface-modifying fine particles which are first dispersed over and attached to the surface of the core particles, and then affixed or formed into a film thereon. The BET specific surface area, based on N.sub.2 adsorption, of the toner particles is less than 0.64 times the BET specific surface area of the core particles and surface-modifying fine particles combined together. Further, this value is 1.07 times the BET specific surface area of hypothetical toner particles which are perfect spheres. Consequently, the toner is not prone to problems such as filming, toner scattering, and fogging which are caused by peeling, separation, etc. of the surface-modifying fine particles, nor to poor cleaning due to spherical toner particles.
    Type: Grant
    Filed: February 17, 1998
    Date of Patent: November 9, 1999
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Yoshiaki Akazawa, Toshihiko Murakami, Tatuo Imafuku, Takeaki Ohuchi, Yasuharu Morinishi, Satoshi Ogawa, Tadashi Nakamura, Hitoshi Nagahama, Toshihisa Ishida
  • Patent number: 5976751
    Abstract: The present invention provides electrophotographic printing-use toner capable of producing a quality image, without depending on excessive addition of a fluidizing agent, even after maintained at high temperature which causes toner to aggregate. The electrophotographic printing-use toner constituting two-component developer with magnetic powder carrier, made of a toner mother particle including binding agent synthetic resin and a coloring agent, whose surface is added with a fluidizing agent is manufactured so that a ratio of .DELTA.Q.sub.h /.DELTA.Q.sub.s is not less than 0.37, more preferably not less than 0.45, where .DELTA.Q.sub.s is a charging rate of the toner mother particle, at a start of mixing with respect to the magnetic powder carrier, maintained at normal temperature, and .DELTA.Q.sub.h is a charging rate of the toner mother particle, at the start of mixing, maintained under a condition of temperature and time which causes the electrophotographic printing-use toner to aggregate.
    Type: Grant
    Filed: April 8, 1998
    Date of Patent: November 2, 1999
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Yasuharu Morinishi, Tadashi Nakamura, Hitoshi Nagahama, Satoshi Ogawa, Toshihisa Ishida, Takeaki Ohuchi