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Magnetic Configuration for Magnetic Brush Developer

IP.com Disclosure Number: IPCOM000088184D
Original Publication Date: 1977-May-01
Included in the Prior Art Database: 2005-Mar-04
Document File: 2 page(s) / 49K

Publishing Venue

IBM

Related People

White, EM: AUTHOR

Abstract

Magnetic fields from magnets within a rotating roller establish strong carrier mix retention in the pickup and transport zones of the magnetic brush roller and weaker carrier mix retention in the developer area.

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Magnetic Configuration for Magnetic Brush Developer

Magnetic fields from magnets within a rotating roller establish strong carrier mix retention in the pickup and transport zones of the magnetic brush roller and weaker carrier mix retention in the developer area.

Latent electrostatic images on photoconductor drum 10 are toned by developer mix transported on the surface of nonmagnetic cylinder 12 under control of magnetic core assembly 13. The developer mix consists of magnetically permeable carrier beads 14, which triboelectrically hold toner and are introduced in pickup zone A from, e.g., a sump or conveyor device (not shown). Stationary magnets 15 through 19, mounted on a high permeability ferrous core 20, control carrier beads 14 as they are transported around roll 12 in the vicinity of the magnets. The mix is attracted to roll 12 by strong radial fields of magnet 15 in pickup area A and is strongly held on roll 12 by magnetic fields linking alternate north and south poles of magnets 15, 16 and 17 through transport area B.

As the mix passes between magnets 16 and 17, the flow along the surface of cylinder 12 is trimmed or smoothed by nonmagnetic doctor blade 11 to assure uniformity of development at developing area C. At area C, the mix is physically constrained between roll sleeve 12 and drum 10. With common polar orientation of magnets 17 and 18 at developing area C, low magnetic forces on the carrier results, because the adjacent like poles produce lower fi...