Patents by Inventor Kazunori Murakawa

Kazunori Murakawa 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).

  • Image forming method of negative latent images using silica particles
    Patent number: 4640882
    Abstract: A negative latent image is formed on a photosensitive member comprising an organic photoconductive material. The negative latent image is developed with a positively chargeable developer containing positively chargeable fine silica particles adapted to the organic photosensitive member. The developed image is transferred to a transfer material and the residual toner on the photosensitive member is removed. Thus, copied images without fog can be obtained successively.
    Type: Grant
    Filed: July 9, 1984
    Date of Patent: February 3, 1987
    Assignee: Canon Kabushiki Kaisha
    Inventors: Yasuo Mitsuhashi, Masaki Uchiyama, Kazunori Murakawa, Kenji Okado
  • Particulate developer containing inorganic scraper particles and image forming method using the same
    Patent number: 4626487
    Abstract: A developer comprising colored resinous particles and inorganic fine particles having a BET specific surface area of 0.2 to 30 m.sup.2 /g as measured by nitrogen adsorption. The inorganic fine particles have an action of promoting removal of paper powder and other adherents during cleaning of the latent image-bearing member without sticking onto the latent image-bearing member. Accordingly, the developer containing the inorganic fine particles can give good images even after successive copying operation for a long term.
    Type: Grant
    Filed: July 25, 1984
    Date of Patent: December 2, 1986
    Assignee: Canon Kabushiki Kaisha
    Inventors: Yasuo Mitsuhashi, Masaki Uchiyama, Kazunori Murakawa, Kenji Okado
  • Developer comprising a modified silicone oil and development process for electrophotography
    Patent number: 4568625
    Abstract: A developer contains a silicone oil which has an amine on side chain thereof, a development process comprises arranging a member holding an electrostatic image on the surface and a member for carrying a toner on the surface and a fixing method comprises contacting a toner image on an image-supporting member with a heated roller, said toner image being formed of a toner which contains a silicone oil having an amine on side chain thereof and has an MI of 0.01-10 g/10 min.
    Type: Grant
    Filed: April 24, 1984
    Date of Patent: February 4, 1986
    Assignee: Canon Kabushiki Kaisha
    Inventors: Masaki Uchiyama, Yasuo Mitsuhashi, Kazunori Murakawa, Masanori Takenouchi, Eiichi Imai, Koushi Suematsu
  • Magnetic toner comprising magnetic powders having controlled size distribution
    Patent number: 4543312
    Abstract: A magnetic toner comprises magnetic powders having a particle distribution that the particle size of 50% accumulated volume, the particle size of 25% accumulated volume and the particle size of 75% accumulated volume of the magnetic powders are 1.5-4.5.mu., 1.0-4.0.mu. and 2.5-6.0.mu., respectively. This magnetic toner can produce high density and clear images and further, can produce colorful images.
    Type: Grant
    Filed: April 26, 1983
    Date of Patent: September 24, 1985
    Assignee: Canon Kabushiki Kaisha
    Inventors: Kazunori Murakawa, Yasuo Mitsuhashi, Hitoshi Uchide, Seiichi Takagi, Masaki Uchiyama, Hisayuki Ochi, Motoo Urawa, Eiichi Imai
  • Magnetic color toner
    Patent number: 4448870
    Abstract: Red to sepia magnetic toners stable to heat and light which do not fade or discolor for a long period of time are prepared by incorporating a partially .alpha.-transformed .gamma.-Fe.sub.2 O.sub.3 as a component in a toner.
    Type: Grant
    Filed: April 11, 1983
    Date of Patent: May 15, 1984
    Assignee: Canon Kabushiki Kaisha
    Inventors: Eiichi Imai, Hitoshi Uchide, Kazunori Murakawa, Masaki Uchiyama, Hisayuki Ochi, Motoo Urawa, Seiichi Takagi, Yasuo Mitsuhashi