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. 07, 1992
Filed:
Apr. 10, 1989
Bruce T Williams, Lockport, NY (US);
Other;
Abstract
A system and method for applying charge to a photoconductive surface wherein an electrode is spaced between the surface and a shield including applying a voltage to the electrode such that current therein is the sum of surface charging current and shield current, utilizing the shield current to obtain a signal proportional to the surface charging current and utilizing that signal to control the application of voltage to the electrode. The shield current and the sum of shield current and surface charging current flow in different directions relative to a current summing node and the signal proportional to surface charging current is obtained from the node. That signal is compared to an input control signal to control the application of voltage to the electrode. A high voltage supply has an output, a return input and a control input and variations in a signal applied to the control input cause variations in the output of the supply. The supply output is coupled to the electrode, the current summing node is connected to the return input, and the shield is connected to the summing node so that as the charging current varies as represented by variations in the voltage at the summing node, the control applies a signal to the control input of the supply to control the charging current.