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. 21, 2003
Filed:
Jun. 26, 2001
Noboru Kawai, Nabari, JP;
Shinya Kawanishi, Tenri, JP;
Sharp Kabushiki Kaisha, Osaka, JP;
Abstract
An object of the invention is to provide a toner density sensor capable of detecting toner density with high accuracy without being affected by the temperature change. A light-emitting diode emits infrared light toward the toner attached to the surface of a photosensitive drum, and the infrared light reflected from the toner is received by a photodiode. An amplifier circuit for detecting color toner density and an amplifier circuit for detecting black toner density, of which both amplify outputs from the photodiode, each employ a thermister for the feedback resistance of the amplifier. An input resistance in the amplifier circuit and the thermister adjust the gain of the amplifier circuit so as to obtain optimal outputs.