Patents by Inventor Takeshi Ohtake

Takeshi Ohtake 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 having negative triboelectric chargeability and developing method
    Patent number: 6218065
    Abstract: A toner having a negative triboelectric chargeability and suitable for developing positively or negatively charged images is composed of at least a binder resin, a colorant and an organic metal compound. The organic metal compound is an organic zirconium compound comprising a coordination or/and a bonding of zirconium and an aromatic compound as a ligand or/and an acid source selected from the group consisting of aromatic diols, aromatic hydroxycarboxylic acids, aromatic monocarboxylic acids, and aromatic polycarboxylic acids.
    Type: Grant
    Filed: December 3, 1998
    Date of Patent: April 17, 2001
    Assignee: Canon Kabushiki Kaisha
    Inventors: Hirohide Tanikawa, Takeshi Ohtake, Makoto Unno, Makoto Kanbayashi
  • Toner for developing electrostatic image and image forming method
    Patent number: 6040103
    Abstract: A toner for developing an electrostatic image is composed of toner particles each containing at least a binder resin, a colorant, and a wax. The wax satisfies conditions of:(a) showing a maximum heat-absorption peak in a region of 50-130.degree. C. on temperature increase on a DSC (differential scanning calorimeter) curve, and(b) giving a .sup.13 C-NMR (nuclear magnetic resonance) spectrum showing a total peak area S in a range of 0-50 ppm, a total peak area S1 in a range of 36-42 ppm and a total peak area S2 in a range of 10-17 ppm satisfying:1.0.ltoreq.(S1/S).times.100.ltoreq.10, 1.5.ltoreq.(S2/S).times.100.ltoreq.15, and S1<S2.The wax satisfying the above-conditions has an appropriately branched long-chain structure and provides the toner with a good balance of good low-temperature fixability and anti-hot-temperature offset characteristic.
    Type: Grant
    Filed: September 2, 1997
    Date of Patent: March 21, 2000
    Assignee: Canon Kabushiki Kaisha
    Inventors: Manabu Ohno, Takeshi Ohtake, Satoshi Matsunaga, Tadashi Doujo
  • Photoconductive film and electrophotographic photosensitive member contains azulenium salt
    Patent number: 4673630
    Abstract: Photoconductive films contain specified azulenium salt compounds. Electrophotographic photosensitive members are provided with a photoconductive film containing at least one of the specified azulenium salt compounds.
    Type: Grant
    Filed: June 6, 1985
    Date of Patent: June 16, 1987
    Assignee: Canon Kabushiki Kaisha
    Inventors: Kazuhara Katagiri, Yoshihiro Oguchi, Takeshi Ohtake, Kozo Arao, Makoto Kitahara, Yoshio Takasu
  • Photoconductive film of azulenium salt and electrophotographic photosensitive member
    Patent number: 4629670
    Abstract: Photoconductive films contain specified azulenium salt compounds. Electrophotographic photosensitive members are provided with a photoconductive film containing at least one of the specified azulenium salt compounds.
    Type: Grant
    Filed: June 7, 1985
    Date of Patent: December 16, 1986
    Assignee: Canon Kabushiki Kaisha
    Inventors: Kazuharu Katagiri, Yoshihiro Oguchi, Takeshi Ohtake, Kozo Arao, Yoshio Takasu