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:
Jul. 01, 1980
Filed:
Apr. 18, 1978
Seiichi Miyakawa, Tokyo, JP;
Susumu Tatsumi, Tokyo, JP;
Koji Sakamoto, Tokyo, JP;
Yoshihiro Ogata, Tokyo, JP;
Ricoh Company, Ltd., Tokyo, JP;
Abstract
A powdered toner mixture comprising a non-magnetic toner component and a ferromagnetic carrier component is caused to flow downwardly through a vertical conduit by gravity. An electromagnetic coil is wound around the conduit and energized with an alternating electric signal. An electrically conductive and magnetic mass is disposed inside the conduit. The permeability of the toner mixture decreases as the toner density, or the ratio of the toner component to the carrier component, increases. The lower the permeability of the toner mixture, the greater the proportion of magnetic flux passing through the mass. The flux passing through the mass induces eddy currents therein which, in combination with hysterisis and skin effect losses, dissipate a portion of the electric signal. The amount of power dissipation is a function of the relative proportion of flux through the mass and thereby the toner density and, when measured, provides a measure of the toner density.