Browse Prior Art Database

Nonmagnetic Seal for Hall Sensor Emitter Wheel

IP.com Disclosure Number: IPCOM000087489D
Original Publication Date: 1977-Feb-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 2 page(s) / 39K

Publishing Venue

IBM

Related People

Berlier, RA: AUTHOR [+2]

Abstract

Contamination of the magnetic emitter wheel disclosed in the IBM Technical Disclosure Bulletin, Vol. 15, No. 4, September 1972, p. 1254, is avoided by the use of two thin, nonmagnetic sealing discs.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 78% of the total text.

Page 1 of 2

Nonmagnetic Seal for Hall Sensor Emitter Wheel

Contamination of the magnetic emitter wheel disclosed in the IBM Technical Disclosure Bulletin, Vol. 15, No. 4, September 1972, p. 1254, is avoided by the use of two thin, nonmagnetic sealing discs.

Fig. 1 shows a portion of a drum-type xerographic copier wherein photoconductor drum 10 cooperates with magnetic brush developer 11. The above-mentioned emitter wheel 12 rotates with drum 10. The magnetic field of this wheel is sensed by stationary Hall sensor 13. The signals thus generated by sensor 13 are used to control the various xerographic process devices (not shown) in accordance with the drum position.

Fig. 2 is an exploded view of wheel 12. This wheel is a laminated construction including a permanent magnet disc 14, one flat surface of which is a north magnetic pole and the opposite parallel flat surface of which is a south pole. A number of holes 15, only two of which are shown, are randomly spaced, to identify desired drum positions. Electrical iron disc 16 includes an extending tab 17 for each of these holes. When disc 16 is laminated to disc 14, these tabs extend through holes 15, and their ends are positioned flush with the opposite surface of disc 14.

As shown in Fig. 3, each of the tabs is surrounded by an air gap 18, thus producing magnetic field 19 for sensing by sensor 13.

In the environment of a copier and particularly one having a magnetic brush developer, magnetically permeable debris, such as the d...