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Magnetic Configuration For Combination Counter Flow and Direct Flow Development In Laser Printer

IP.com Disclosure Number: IPCOM000048864D
Original Publication Date: 1982-Apr-01
Included in the Prior Art Database: 2005-Feb-09
Document File: 3 page(s) / 47K

Publishing Venue

IBM

Related People

White, EM: AUTHOR

Abstract

This article relates to the control of a magnetizable carrier (or magnetizable toner) between two active developing rolls within a printer such that a desirable apportionment of mix results on each of two rolls. By properly selecting the magnetics of two adjacent magnetic brush rolls a means is provided to proportion developer mix between two development rolls, one of which serves also as a conveyor of mix from a sump.

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Magnetic Configuration For Combination Counter Flow and Direct Flow Development In Laser Printer

This article relates to the control of a magnetizable carrier (or magnetizable toner) between two active developing rolls within a printer such that a desirable apportionment of mix results on each of two rolls. By properly selecting the magnetics of two adjacent magnetic brush rolls a means is provided to proportion developer mix between two development rolls, one of which serves also as a conveyor of mix from a sump.

In Fig. 1, magnetically attractable carrier mix is picked up from sump 13 by roll 1 and under the influence of magnetic fields of magnets 3 and 4. The peak fields over these magnets at the roll surface are about 700 gauss. The mix is then transported by roll 1 under the influence of magnets 4, 5, and 6 in the direction indicated, where it passes through a gate 14 which controls the total amount of flow desired for development. The magnetic field strength is reduced to about 500 gauss at magnet 5 which is strong enough to contain ample mix yet allows for less drag of the mix through the gate. As the mix passes over magnet 6, the outer portion of the mix layer on roll 1 becomes attracted to roll 2 under the influence of magnet 9.

Fig. 2 shows the magnetic field pattern in the vicinity of the gap between the two rolls. From this one sees that the fields decrease and then become strong again in going from roll 1 to roll 2 in the gap region. Yet the fields close to roll 1 are strong enough to retain mix on or near its surface. Likewise, mix that gets captured by roll 2 is also captured by the strong fields of magnet 9.

A stable division of mix occurs with no mix chaining between rolls that could cause instability and nonuniformity of flow around the rolls. Mix on roll 2 continues on through development zone 16 in direct flow with the photoconductor 15.

Magnets 9 and 10 provide a de...