Patents Assigned to Pram Inc.
  • Patent number: 3939800
    Abstract: An apparatus for depositing electrostatically and magnetically responsive particulate matter on a conductive surface having an electrostatically charged latent image comprises an elongate permanent magnet that is disposed adjacent to the conductive surface and that is capable of producing a magnetic field having a region of concentrated magnetic flux that permeates the surface and also a region of dilute magnetic flux that is inclined and generally adjacent to the surface, a hopper for storing the particulate matter, and a channel connected to the hopper disposed in the region of dilute magnetic flux having two opposite converging walls that terminate adjacent to the conductive surface in the region of concentrated magnetic flux. The particulate matter when introduced to the region of dilute magnetic flux is caused to be moved by magnetic forces and gravitational forces from the region of dilute magnetic flux to the region of concentrated magnetic flux.
    Type: Grant
    Filed: July 23, 1974
    Date of Patent: February 24, 1976
    Assignee: Pram Inc.
    Inventor: Harold J. Banker