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. 12, 1982
Filed:
Aug. 27, 1980
Manabu Mochizuki, Tokyo, JP;
Seiichi Miyakawa, Tokyo, JP;
Taro Kimura, Tokyo, JP;
Junichiro Hashimoto, Tokyo, JP;
Ricoh Company, Ltd., Tokyo, JP;
Abstract
First and second sensors (37), (39) are provided in a developing tank (36) containing a liquid developer consisting of a liquid carrier or dispersant and toner particles dispersed in the carrier. The first sensor (37) measures the electrical resistivity of the developer whereas the second sensor (39) measures the optical transmissibility thereof. Additional toner is supplied into the developer to maintain the transmissivity at a value which is a predetermined function of the resistivity. The transmissibility value is reduced as the resistivity increases, thereby maintaining the copy image density constant. The first sensor (37) includes two electrodes immersed in the developer and an A.C. or D.C. voltage is applied thereacross. The current flow through the electrodes (37) and thereby the developer is measured to determine the resistivity of the developer. Where the applied voltage is D.C., an arrangement is provided to mechanically scrape accumulated developer off the electrodes (37) at intermittent intervals.