Patents by Inventor Tadashi Yamashita

Tadashi Yamashita 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: 4400081
    Abstract: An apparatus for cleaning a photosensitive member of an electrostatic copying machine which includes neutralizing means electrically connected to the ground and disposed for contact with the surface of a photosensitive member in a region located between a transfer station where a toner image formed on photosensitive member is transferred onto a transfer sheet and a cleaning station where any residual toner remaining on the photosensitive member after the transfer step is removed. In this manner, the photosensitive member is neutralized after the transfer step before the residual toner is removed therefrom.
    Type: Grant
    Filed: July 20, 1981
    Date of Patent: August 23, 1983
    Assignee: Ricoh Company, Ltd.
    Inventors: Tadashi Yamashita, Toyoo Okamoto
  • Patent number: 4183655
    Abstract: An image transfer unit provided with cleaning means for use in an electrophotographic copying machine comprising an electrically conductive transfer roller disposed in abutting relationship with a photosensitive member, an electrically conductive, rotatable cleaning means disposed in abutting relationship with the transfer roller, and electrical bias means connected with the cleaning means and having a switchable polarity. During a transfer step, a bias voltage of opposite polarity to that of the toner is applied to the transfer roller through the cleaning means. At this time, toner attaching to the transfer roller is electrostatically transferred onto the cleaning means. During a cleaning step, a bias voltage of the same polarity as the toner is applied to the cleaning means, whereby the toner attaching thereto is transferred back to the photosensitive member through the transfer roller. The toner which is transferred back to the photosensitive member is removed by separate cleaning means.
    Type: Grant
    Filed: May 22, 1978
    Date of Patent: January 15, 1980
    Assignee: Ricoh Company, Ltd.
    Inventors: Minoru Umahashi, Hideo Yamazaki, Mitsuo Hasebe, Tadashi Yamashita
  • Patent number: 4034221
    Abstract: The charging device for automatic copying apparatus comprises charging wires supplied with a charge voltage at all times and a plurality of lamps disposed in the rearward position of the charging device. As turning on of the lamps can prevent the photoconductor from charging by the charging wires, a charged zone corresponding to the effective image region can be produced on the photoconductor by controlling turning on and off of the lamps.
    Type: Grant
    Filed: March 31, 1976
    Date of Patent: July 5, 1977
    Assignee: Ricoh Co., Ltd.
    Inventor: Tadashi Yamashita