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:
Sep. 14, 1993
Filed:
Dec. 20, 1991
Kouji Ishigaki, Yokohama, JP;
Yusuke Shimbo, Tokyo, JP;
Ricoh Company, Ltd., Tokyo, JP;
Abstract
A device incorporated in image forming equipment for adjusting the output of an image density sensor which optically senses the density of a toner image formed on a photoconductive element and representative of a reference pattern. The density sensor is made up of a light emitting element and a light-sensitive element. Thresholds divide an output range wherein the output characteristic of the sensor does not change into a plurality of subranges having the optimal output associated with the background of the photoconductive element as the center value. The sensor senses the background of the photoconductive element at predetermined intervals. Whether or not to adjust the output of the sensor is determined on the combination of the subrange where the resulting output of the sensor lies and the number of times that the former lies in the latter. The sensor output, i.e., a PWM (Pulse Width Modulation) duty to be fed to the light emitting element is changed to control the adjusted output associated with the background to the optimal value.