Patents by Inventor Katsukiyo Nagai

Katsukiyo Nagai 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).

  • Electrophotographic photoconductor and aromatic polycarbonate resin for use therein
    Patent number: 6194535
    Abstract: An electrophotographic photoconductor has an electroconductive support, and a photoconductive layer which is formed on the support and contains as an effective component an aromatic polycarbonate resin having a structural unit of formula (I), or the structural unit of formula (I) and a structural unit of formula (II): wherein Ar1 to Ar5, R1, and X are as specified in the specification.
    Type: Grant
    Filed: November 1, 1999
    Date of Patent: February 27, 2001
    Assignee: Ricoh Company, Ltd.
    Inventors: Akira Katayama, Masaomi Sasaki, Katsukiyo Nagai, Chiaki Tanaka, Shinichi Kawamura, Tetsuro Suzuki, Susumu Suzuka, Katsuhiro Morooka
  • Electrophotographic photoconductor and aromatic polycarbonate resin for use therein
    Patent number: 6172176
    Abstract: An electrophotographic photoconductor has an electroconductive support, and a photoconductive layer which is formed thereon and contains as an effective component an aromatic polycarbonate resin having a structural unit of formula (1), two structural units of formula (1) and (2), or a repeat unit of formula (3): wherein R1 and R2, Ar1 to Ar8, X, Y, s and n are as specified in the specification. The above-mentioned aromatic polycarbonate resin is provided with charge transporting properties.
    Type: Grant
    Filed: June 22, 1999
    Date of Patent: January 9, 2001
    Assignee: Ricoh Company, Ltd.
    Inventors: Chiaki Tanaka, Masaomi Sasaki, Katsukiyo Nagai, Shinichi Kawamura, Susumu Suzuka, Katsuhiro Morooka
  • Electrophotographic photoconductor and aromatic polycarbonate resin for use therein
    Patent number: 6130310
    Abstract: An electrophotographic photoconductor includes an electroconductive support, and a photoconductive layer formed thereon containing as an effective component an aromatic polycarbonate resin having a structural unit of formula (I), or in combination with a structural unit of formula (II); ##STR1## wherein R, R.sup.1, and X are as specified in the specification.
    Type: Grant
    Filed: November 12, 1999
    Date of Patent: October 10, 2000
    Assignee: Ricoh Company, Ltd.
    Inventors: Akira Katayama, Masaomi Sasaki, Katsukiyo Nagai, Chiaki Tanaka, Shinichi Kawamura, Susumu Suzuka, Katsuhiro Morooka
  • Electrophotographic photoconductor and aromatic polycarbonate resin for use therein
    Patent number: 6066428
    Abstract: An electrophotographic photoconductor has an electroconductive support, and a photoconductive layer which is formed on the support and contains as an effective component an aromatic polycarbonate resin having a structural unit of formula (I), or the structural unit of formula (I) and a structural unit of formula (II): ##STR1## wherein Ar.sup.1 to Ar.sup.5, R.sup.1, and X are as specified in the specification.
    Type: Grant
    Filed: June 19, 1998
    Date of Patent: May 23, 2000
    Assignee: Ricoh Company, Ltd.
    Inventors: Akira Katayama, Masaomi Sasaki, Katsukiyo Nagai, Chiaki Tanaka, Shinichi Kawamura, Tetsuro Suzuki, Susumu Suzuka, Katsuhiro Morooka
  • Electrophotographic photoconductor and aromatic polycarbonate resin for use therein
    Patent number: 6045959
    Abstract: An electrophotographic photoconductor includes an electroconductive support, and a photoconductive layer formed thereon containing as an effective component an aromatic polycarbonate resin having a structural unit of formula (I), or in combination with a structural unit of formula (II): ##STR1## wherein R, R.sup.1, and X are as specified in the specification.
    Type: Grant
    Filed: April 15, 1998
    Date of Patent: April 4, 2000
    Assignee: Ricoh Company, Ltd.
    Inventors: Akira Katayama, Masaomi Sasaki, Katsukiyo Nagai, Chiaki Tanaka, Shinichi Kawamura, Susumu Suzuka, Katsuhiro Morooka
  • Electrophotographic photoconductor and aromatic polycarbonate resin for use therein
    Patent number: 5976746
    Abstract: An electrophotographic photoconductor has an electroconductive support, and a photoconductive layer which is formed thereon and contains as an effective component an aromatic polycarbonate resin having a structural unit of formula (1), two structural units of formula (1) and (2), or a repeat unit of formula (3): ##STR1## wherein R.sup.1 and R.sup.z Ar.sup.1 to Ar.sup.6, X, Y, s and n are as specified in the specification. The above-mentioned aromatic polycarbonate resin is provided with charge transporting properties.
    Type: Grant
    Filed: June 11, 1998
    Date of Patent: November 2, 1999
    Assignee: Ricoh Company, Ltd.
    Inventors: Chiaki Tanaka, Masaomi Sasaki, Katsukiyo Nagai, Shinichi Kawamura, Susumu Suzuka, Katsuhiro Morooka