Patents Examined by Ronald E. Martin
  • Patent number: 4971881
    Abstract: A toner composition for use in electrophotography comprises a rosin modified styrene-acrylic binder resin which has been prepared by steam stripping a mixture solution polymerized styrene acrylic copolymer resin, rosin and a suitable solvent such a toluene or xylene followed by cooling and grinding to form styrene acrylic/rosin binder resin. This binder resin is then formulated with conventional coloring pigments, charge controlling dyes and carriers such as iron powder or glass beads to provide dry toner compositions of high positive charge. An important feature of the present invention is that the styrene acrylic/rosin binder resin will have an inherent positive charge of at least 2.0. This inherent positive charge is in contrast to typical prior art toner binders which are inherently negatively charged.
    Type: Grant
    Filed: January 5, 1989
    Date of Patent: November 20, 1990
    Assignee: Monsanto Company
    Inventors: Gary Deets, Richard M. Zielinski
  • Patent number: 4218528
    Abstract: The method for forming an electrostatic image according to the present invention comprises the steps of charging an electrophotographic photoreceptor, which is subjected to dark decay after the charging step, and effecting an exposure by activation light and an imagewise exposure on the electrophotographic photoreceptor. The exposure by activation light is effected prior to the imagewise exposure and in a step including at least a portion of the charging step or dark decay. This causes a remarkable sensitization effect in the electrophotographic photoreceptor, suitably adapted for use in an electrophotographic copying machine of a repeated transfer type.
    Type: Grant
    Filed: June 8, 1978
    Date of Patent: August 19, 1980
    Assignee: Konishiroku Photo Industry Co., Ltd.
    Inventors: Fumio Shimada, Masatoshi Matsuzaki, Masafumi Uehara