The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 18, 1994
Filed:
Dec. 30, 1991
Jorge A Alvarez, Rochester, NY (US);
Gary A Denton, Webster, NY (US);
Peter J McGuire, Rochester, NY (US);
Francisco Zirilli, Walworth, NY (US);
Xerox Corporation, Stamford, CT (US);
Abstract
An electrophotographic printing machine in which an electrostatic latent image is recorded on a photoconductive surface by charging the appropriate areas of the surface to predetermined polarities. The latent image is a developed with toners of a preselected color and predetermined polarity by a developer unit. The developer unit includes a bead removal device which magnetically attracts carrier beads off the photoconductive surface and deposits these beads in a sump or reservoir of developer. The bead removal device includes a magnet and magnetic field shapers to enhance the magnetic fields which attract the beads in the zone between the surface and the bead removal device and attenuates the magnetic fields in the zone between the bead removal device and the sump or reservoir to reduce the attraction between the beads and the bead removal device in this zone. The invention also provides magnetic brush rollers for the delivery of toner to the photoconductive surface which have magnetic field shapers which attenuate the magnetic fields to encourage bead release from the roller and reduce attraction of beads to the roller in reverse rotation of the roller.