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Browse Prior Art Database

LOW TONER SENSOR

IP.com Disclosure Number: IPCOM000024916D
Original Publication Date: 1982-Oct-31
Included in the Prior Art Database: 2004-Apr-04
Document File: 2 page(s) / 81K

Publishing Venue

Xerox Disclosure Journal

Abstract

A low toner sensor is shown that relies upon the detection of a change in the electrical impedance of an electro-acoustic transducer when the mechanical damping is changed by intimate contact with toner in a toner sump.

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XEROX DIĀ§CLOSURE JOURNAL

A low toner sensor is shown that relies upon the detection of a change in the electrical impedance of an electro-acoustic transducer when the mechanical damping is changed by intimate contact with toner in a toner sump.

The electro-acoustic transducer is a small earphone insert referred to as TELE- TH@, a registered trademark of Telex Communications, Inc. The earphone is essentially a coil, magnet and diaphragm shown in Figure 1. The electrical impedance at the mechanical resonant frequency (-2KHz) changes from- 700 to -1300 ohms when the TELETHI @ is brought into contact with a bulk toner mass. This method of detecting this impedance change depends upon the change in the positive feedback (could be either the positive or negative) loop of an amplifier which starts or stops oscillation at the mechanical resonant frequency of the TELETHId?

Volume 7 Number 5 September/October 1982 33 1

LOW TONER SENSOR
R. W. Huggins

A. J. WerGr

Proposed Classification
U.S. C1. 355/3DD Int. Cl. G03g 15/00

TE L E T HI N?

n

*TUNING C+R

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LOW TONER SENSOR (Cont'd)

With reference to the figure, the negative feedback components are chosen to satisfy the phase criterion for oscillation close to the mechanical resonant frequency of the TELETHI@, and to decrease the gain at high and low frequencies in order to prevent spurious oscillation at other frequencies.

In the positive feedback looper, the "fe...