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:
Aug. 31, 1982
Filed:
Jun. 25, 1979
P Keith Watson, Rochester, NY (US);
Lawrence J Fraser, Rochester, NY (US);
Xerox Corporation, Stamford, CT (US);
Abstract
An automatic development control for use in an electrophotographic apparatus. The control includes a pair of substantially planar members forming a channel therebetween through which developer flows. One of the members is constructed such that an electrostatic charge pattern is periodically formed on the surface thereof, the charge pattern being developed by the attraction of toner thereto which toner has a charge opposite to that forming the charge pattern. The member on which the developed charge pattern is formed includes a uniform, transparent conducting substrate covered with a transparent insulating layer on top of which is deposited a set of spaced-apart, opaque and electrically conducting fingers. Thus, the one member includes alternate opaque and transparent areas. By grounding the electrically conducting fingers which are all interconnected and by driving the substrate alternately positive and negative, toner is deposited on the transparent areas during the application of one half cycle of voltage and during the following half cycle the toner is deposited on the opaque fingers and scavenged from the transparent areas. The optical density of the toner deposited is directly related to the toner concentration in the developer. The one member then forms part of the toner concentration control.