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TONER CONCENTRATION METER

IP.com Disclosure Number: IPCOM000024386D
Original Publication Date: 1980-Jun-30
Included in the Prior Art Database: 2004-Apr-02
Document File: 2 page(s) / 63K

Publishing Venue

Xerox Disclosure Journal

Abstract

In an electrophotographic printing machine, developer materials frequently employed in the magnetic brush development system are ferromagnetic. The effective permeability of the developer materials depend upon the toner particle concentration. As the effective permeability of the developer material decreases monotonically, the toner particle concentration increases. In order to utilize the foregoing properties, the developer material may flow through a tube 10 located in the air core of a transformer. The primary windings 12 of the transformer are excited with an alternating current input. The secondary windings 14 produce an alternating current output.

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XEROX DISCLOSURE JOURNAL

TONER CONCENTRATION METER Proposed Thomas T. Tso Classification

U.S. Cl. 427/145 Int. C1. B41m 5/16

In an electrophotographic printing machine, developer materials frequently employed in the magnetic brush development system are ferromagnetic. The effective permeability of the developer materials depend upon the toner particle concentration. As the effective permeability of the developer material decreases monotonically, the toner particle concentration increases. In order to utilize the foregoing properties, the developer material may flow through a tube 10 located in the air core of a transformer. The primary windings 12 of the transformer are excited with an alternating current input. The secondary windings 14 produce an alternating current output.

Turning now to Figure 2, the read-out circuit is a tuned secondary circuit, which has a characteristically sharp resonance point. Developer material with different toner concentrations will have different resonous frequencies depending upon the effective permeability. If the driving frequency is tuned for one particular toner concentration, then the read-out voltage will be a maximum at this toner concentration. Developer materials with slightly different toner concentrations will yield smaller output voltages due to the sharp drop in the resonous frequency. Thus, by varying the driving frequency, the toner concentration of various developer material can be readily determined.

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