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. 01, 1991
Filed:
Nov. 08, 1989
Richard F Lehman, Webster, NY (US);
James D Rees, Pittsford, NY (US);
Xerox Corporation, Stamford, CT (US);
Abstract
A sensor array is positioned in the optical scanning system of a copier so as to be able to periodically provide a measurement of the degree of image degradation present in the system due to contamination of the optical system components. The sensor array is adapted to measure the modulation transfer frequency of a bar chart which is exposed in the optical system. The measured value of MTF is compared to a predetermined value of MTF representing a uncontaminated measurement at the bar chart. When the comparison indicates that the measured MTF is below a minimum acceptable threshold value, a display is activated to alert an operator that an optic system cleaning operation is required.