Patents Examined by S. Crosson
  • Patent number: 5008172
    Abstract: An electrophotographic photoconductor is disclosed, which comprises an electroconductive substrate, a photoconductive layer formed on the electroconductive substrate, and a protective layer formed on the photoconductive layer, the protective layer comprising a binder resin and finely-divided particles of at least one metal oxide with the surface thereof being coated with a coupling agent selected from the group consisting of a titanate-type coupling agent, a fluorine-containing silane coupling agent, and an acetoalkoxyaluminum diisopropylate, dispersed in the binder resin.
    Type: Grant
    Filed: May 24, 1989
    Date of Patent: April 16, 1991
    Assignee: Ricoh Company, Ltd.
    Inventors: Takashi Rokutanzono, Yukio Ide, Hiroshi Nagame, Kohichi Ohshima, Narihito Kojima, Shinji Nousho
  • Patent number: 4980258
    Abstract: The present invention relates to the positively chargeable black toner particles which comprise binder resins, carbonblack as a main colorant, quaternary anmonium salt of the following formula (I) as a charge control agent and .beta.-form Cu-phthalocyanine as a stabilizing agent for chargeability of toner particles without being affected by the change of environmental conditions. ##STR1## Wherein R.sub.1 is C.sub.1 -C.sub.8 alkyl or benzyl, R.sub.2 and R.sub.3 are each C.sub.1 -C.sub.18 alkyl, R is C.sub.1 -C.sub.118 alkyl or benzyl, X is hydroxy or amino, and Y is hydoroxy or hydrogen; (c) .beta.-form Cu-phthalocyanine; and (d) carbonblack.The present invention further relates to the two component dry-type developer composed by the improved above said positively chargeable toner particles and the carrier particles coated with silicone polylmers which have the strong durability without being changed to a supent carrier particles for a use of long time period.
    Type: Grant
    Filed: November 14, 1989
    Date of Patent: December 25, 1990
    Assignee: Ricoh Company, Ltd.
    Inventors: Mitsuo Aoki, Nobuhiro Nakayama, Yasuo Asahina, Hiroyuki Fushimi, Kayo Makita, Yasuaki Iwamoto