Patents by Inventor Atsushi Kamitakahara

Atsushi Kamitakahara 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: 4868102
    Abstract: A light-sensitive silver halide direct-positive photographic material which comprises a support and, provided thereon a light-sensitive direct-positive silver halide emulsion layer containing silver halide grains having an internal latent image and a core-shell structure comprising a core and at least one shell stratum either partly or entirely covering said core, the outermost stratum of said shell having been formed in the presence of a nitrogen-containing heterocyclic compound having a mercapto group therein.
    Type: Grant
    Filed: February 2, 1988
    Date of Patent: September 19, 1989
    Assignee: Konica Corporation
    Inventors: Keiji Ogi, Atsushi Kamitakahara, Eiichi Sakamoto, Nariko Isozaki
  • Patent number: 4749644
    Abstract: In a light-sensitive direct posi silver halide color photographic material having photographic constituent layers comprising at least one silver halide emulsion layer containing latent image type silver halide grains not previously fogged, which is capable of giving a direct posi image by subjecting the whole surface to exposure or effecting surface development in the presence of a fogging agent, after image exposure, the improvement wherein said internal latent image type silver halide grains are composed of at least two groups of internal latent image type silver halide grains having average grain sizes different from each other, and at least one compound capable of releasing a development inhibiting substance or its precursor through the reaction with the oxidized product of a color developing agent is contained in at least one layer of said photographic constituent layers.
    Type: Grant
    Filed: June 18, 1986
    Date of Patent: June 7, 1988
    Assignee: Konishiroku Photo Industry Co., Ltd.
    Inventors: Yasuo Tosaka, Keiji Ogi, Atsushi Kamitakahara
  • Patent number: 4433049
    Abstract: Disclosed is a method for preparing a light-sensitive cuprous halide emulsion which comprises reducing cupric ions by an ascorbic acid derivative represented by the general formula: ##STR1## wherein R is a hydrogen atom or a hydroxyl group, and n is an integer of 1 to 4, provided that R is a hydroxyl group when n is 1, or its alkali metal salt, in the presence of halogen ions.
    Type: Grant
    Filed: February 10, 1982
    Date of Patent: February 21, 1984
    Assignee: Konishiroku Photo Industry Co., Ltd.
    Inventors: Noboru Itoh, Toshiaki Takahashi, Keiji Ogi, Atsushi Kamitakahara