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:
Nov. 26, 2019
Filed:
May. 21, 2019
Lexmark International, Inc., Lexington, KY (US);
Michael Brian Bacelieri, Lexington, KY (US);
Douglas Anthony Able, Shelbyville, KY (US);
Andrew Pryse Dale, Lexington, KY (US);
Jared Kuohui Lin, Lexington, KY (US);
Robert Watson McAlpine, Lexington, KY (US);
Matthew Russell Smither, Lexington, KY (US);
LEXMARK INTERNATIONAL, INC., Lexington, KY (US);
Abstract
An imaging device includes a photoconductive drum charged by a charge roll and opposed by a transfer roll to transfer an image from the drum. The drum becomes biased to a negative voltage by setting charges of negative voltage on both the charge roll and transfer roll. A controller switches the bias of the transfer roll to a positive voltage from the negative voltage and a delta or difference in a charge of the drum is determined from before and after the switching. Based on the delta, the voltage on the charge roll is boosted by a boost voltage to improve the charge on the drum. In this way, deteriorating or defective charge rolls can be still used to charge the drum to a proper voltage for imaging. Techniques for determining the delta, the boost and the magnitude of voltage charges are further embodiments.