Patents by Inventor Tomotsugu Miyamoto

Tomotsugu Miyamoto 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).

  • Process for the production of toner for developing electrostatic image
    Patent number: 6503681
    Abstract: A two-step process for the production of a toner for developing electrostatic images, including a first pulverizing step wherein a toner composition containing a binder and a coloring agent is pulverized to obtain preliminarily pulverized particles having a weight average particle diameter of 20-100 &mgr;m and containing no more than 50% by weight of particles having roundness of 0.90 or less, and a second pulverizing step wherein the preliminarily pulverized particles are finely pulverized to obtain finely pulverized particles having a weight average particle diameter of 5-13 &mgr;m and containing no more than 30% by weight of particles having roundness of 0.90 or less and no more than 15%, based on the total number of particles of the finely pulverized particles, of particles having a particle diameter of 5 &mgr;m or less.
    Type: Grant
    Filed: December 21, 2000
    Date of Patent: January 7, 2003
    Assignee: Ricoh Company, Ltd.
    Inventors: Nobuyasu Makino, Tomotsugu Miyamoto, Mitsuyoshi Izu, Ryoichi Ito, Yasuaki Iwamoto, Kazuyuki Yazaki
  • Method of producing toner for developing latent electrostatic images
    Patent number: 6368765
    Abstract: A method of producing a toner for developing latent electrostatic images includes the steps of preliminarily grinding a toner composition having at least a binder resin and a coloring agent to prepare a preliminarily ground product, and finely pulverizing the preliminarily ground product using a pulverizer to produce toner particles, wherein the preliminarily ground product satisfies conditions (1) and (2): Dv≧D10  (1) D50<3D10  (2) wherein Dv is a weight mean diameter of the preliminarily ground product, D10 is a weight mean diameter when the cumulative number of particles reaches 10% at measurement of a cumulative particle distribution, and D50 is a weight mean diameter when the cumulative number of particles reaches 50% at measurement of the cumulative particle distribution.
    Type: Grant
    Filed: January 22, 2001
    Date of Patent: April 9, 2002
    Assignee: Ricoh Company, Ltd.
    Inventors: Mitsuyoshi Izu, Nobuyasu Makino, Tomotsugu Miyamoto, Yasuaki Iwamoto, Ryoichi Ito, Kazuyuki Yazaki
  • Method of producing toner for developing latent electrostatic images
    Publication number: 20010010888
    Abstract: A method of producing a toner for developing latent electrostatic images includes the steps of preliminarily grinding a toner composition having at least a binder resin and a coloring agent to prepare a preliminarily ground product, and finely pulverizing the preliminarily ground product using a pulverizer to produce toner particles, wherein the preliminarily ground product satisfies conditions (1) and (2):
    Type: Application
    Filed: January 22, 2001
    Publication date: August 2, 2001
    Applicant: Ricoh Company, Ltd.
    Inventors: Mitsuyoshi Izu, Nobuyasu Makino, Tomotsugu Miyamoto, Yasuaki Iwamoto, Ryoichi Ito, Kazuyuki Yazaki
  • Process for the production of toner for developing electrostatic image
    Publication number: 20010006197
    Abstract: A two-step process for the production of a toner for developing electrostatic images, including a first pulverizing step wherein a toner composition containing a binder and a coloring agent is pulverized to obtain preliminarily pulverized particles having a weight average particle diameter of 20-100 &mgr;m and containing no more than 50% by weight of particles having roundness of 0.90 or less, and a second pulverizing step wherein the preliminarily pulverized particles are finely pulverized to obtain finely pulverized particles having a weight average particle diameter of 5-13 &mgr;m and containing no more than 30% by weight of particles having roundness of 0.90 or less and no more than 15%, based on the total number of particles of the finely pulverized particles, of particles having a particle diameter of 5 &mgr;m or less.
    Type: Application
    Filed: December 21, 2000
    Publication date: July 5, 2001
    Applicant: RICOH COMPANY, LTD.
    Inventors: Nobuyasu Makino, Tomotsugu Miyamoto, Mitsuyoshi Izu, Ryoichi Ito, Yasuaki Iwamoto, Kazuyuki Yazaki