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Magnet Configuration for Magnetic Brush Developer

IP.com Disclosure Number: IPCOM000082838D
Original Publication Date: 1975-Feb-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 3 page(s) / 105K

Publishing Venue

IBM

Related People

Knight, AH: AUTHOR

Abstract

A magnet configuration of a magnetic brush developer unit employs a pair of magnets laid on their sides, so that normal magnetic fields at the magnetic brush surface exist over the ends of the magnet. Additionally, a unique magnetic field is generated in the developing zone of the magnetic brush, which enhances the developability of an electrostatic image rotating therepast.

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Magnet Configuration for Magnetic Brush Developer

A magnet configuration of a magnetic brush developer unit employs a pair of magnets laid on their sides, so that normal magnetic fields at the magnetic brush surface exist over the ends of the magnet. Additionally, a unique magnetic field is generated in the developing zone of the magnetic brush, which enhances the developability of an electrostatic image rotating therepast.

An electrostatic image located on the surface of drum 11, rotating in the direction of arrow 13, moves past magnetic brush unit 15, rotating in the direction of arrow 17, to be developed thereby. Magnetic developer material is delivered to the lowermost surface of the rotating magnetic brush unit 15 by the magnetic conveyor roll 19, rotating in the direction of arrow 21.

The delivered developer material adheres to the surface of magnetic brush unit 15, because of the magnetic fields generated by magnets 23, 25, and 27 of the magnetic brush unit. Excess developer material is removed by control device 29 prior to the developer material contacting rotating drum 11. The developer material is slung from the surface of the magnetic brush 15, once it is no longer under the influence of the magnetic fields.

The magnetic field has both tangential and normal components which are plotted in Fig. 2. Strong normal and tangential fields are employed in area 1 as the developer material approaches the development zone of area 2, to insure control of the developer material and a smooth steady flow toward the development zone. As the developer material enters area 2 which defines the start of the development zone, a rapidly falling tangential field and the strong sharply pointed normal field causes the developer material to stand up rapidly, creating turbulence and tumbling whi...