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:
Jun. 11, 2002
Filed:
Jan. 29, 2001
Robert Edmund Grace, Fairport, NY (US);
Xerox Corporation, Stamford, CT (US);
Abstract
In an electrophotographic imaging system, a toner density control method and apparatus that uses software modeling to instantaneously compensate for image density variations due to fluctuations in toner concentration. A time-delay model of developer housing dynamics is maintained in machine software of a controller that approximates delay between toner concentration sensing and image development, delay caused by toner-carrier mixing, and/or delay caused by transport of toner-carrier from the development housing to the developer roll. The approximations can be adjusted according to actual measurements over the last several minutes of operation. The controller compares predicted toner concentration sensor signals with averaged actual toner concentration sensor signals to detect long-term and/or short-term drift. Based on the approximations and detected drift, the controller computes and transmits a feed forward correction signal to adjust electrostatic setpoints of an electrostatic controller on a print-by-print basis in order to compensate for fluctuations in toner.