Patents by Inventor Jyunshin Sakamoto

Jyunshin Sakamoto 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).

  • Driving system for a semiconductor laser device
    Patent number: 7206329
    Abstract: When a semiconductor laser is energized, a virtual junction temperature rises to reduce a threshold current, which fluctuates a light output by the unit of a several microseconds, thereby causing printing irregularity. An object of the invention is to prevent the fluctuation in light output occurring due to the temperature change caused by the energization of the semiconductor laser with a simple circuit structure and under the driving condition of a small bias current. A constant voltage driving is performed with a circuit or device having negative resistance characteristics being arranged in series with the semiconductor laser. Thus, the reduction in light output of the semiconductor laser due to the temperature rise is compensated for by an increase in driving current thanks to a reduction in rising voltage of current/voltage characteristics.
    Type: Grant
    Filed: June 21, 2004
    Date of Patent: April 17, 2007
    Assignee: Ricoh Printing Systems Co., Ltd.
    Inventors: Shinichi Nakatsuka, Jyunshin Sakamoto, Hiroshi Inenaga, Susumu Saito
  • Laser exposing system and laser printer using the same
    Publication number: 20050169329
    Abstract: When a semiconductor laser is energized, a virtual junction temperature rises to reduce a threshold current, which fluctuates a light output by the unit of a several microseconds, thereby causing printing irregularity. An object of the invention is to prevent the fluctuation in light output occurring due to the temperature change caused by the energization of the semiconductor laser with a simple circuit structure and under the driving condition of a small bias current. A constant voltage driving is performed with a circuit or device having negative resistance characteristics being arranged In series with the semiconductor laser. Thus, the reduction in light output of the semiconductor laser due to the temperature rise is compensated for by an increase in driving current thanks to a reduction in rising voltage of current/voltage characteristics.
    Type: Application
    Filed: June 21, 2004
    Publication date: August 4, 2005
    Inventors: Shinichi Nakatsuka, Jyunshin Sakamoto, Hiroshi Inenaga, Susumu Saito