Lexmark International, Inc.

Elliott Vincent Jernigan

Gary Allen Denton

Katherine Marie Gilliam

Matthew Lee Rogers

Robert Dan Bennett, Iii

Dominique Renee Rowe

Courtney Harrison Soale

Royden Thomas Kern

Michael Brian Bacelieri

Daniel Enrique Alonzo

Keith Seaman

Michael David Maul

Mark Doerre

Robert Christopher Sbert

Robert Dan Iii Bennett

An outer sleeve of a magnetic roll for a dual component development electrophotographic image forming device according to one example embodiment includes a series of grooves in an outer surface of the outer sleeve. The grooves extend along an axial length of the sleeve and are spaced circumferentially from each other around the outer sleeve. The outer sleeve has a diameter of between 15 mm and 30 mm, inclusive. The grooves are present on the outer surface of the outer sleeve at a groove density of at least 1.91 grooves/mm of the circumference of the outer surface of the outer sleeve and a total indicated runout of the outer sleeve is 0.05 mm or less.

Magnetic roll for a dual component development electrophotographic image forming device

A developer unit according to one example embodiment includes a housing having a reservoir for storing a developer mix that includes toner and magnetic carrier beads. A magnetic roll includes a stationary core and a sleeve positioned around the core that is rotatable relative to the core. The stationary core includes at least one permanent magnet having circumferentially spaced magnetic poles. An upper and a lower magnetically permeable metal shunt are positioned at each axial end of the magnetic roll. Each upper shunt and each lower shunt is positioned axially outboard of the core and in close proximity to the outer surface of the sleeve.

End sealing and magnetic field truncation of a magnetic roll of a dual component development electrophotographic image forming device

A developer unit for a dual component development electrophotographic image forming device includes a housing having a reservoir for storing a developer mix that includes toner and magnetic carrier beads. An axial sealing rib projects from an inner side of the housing toward the outer surface of a sleeve of a magnetic roll. The axial sealing rib extends along an axial length of the sleeve. A distal end of the axial sealing rib is positioned in close proximity to and spaced from the outer surface of the sleeve. The axial sealing rib is positioned to impede the flow of developer mix in the reservoir in a direction counter to an operative rotational direction of the sleeve.

Sealing ribs for a developer unit of a dual component development electrophotographic image forming device

A developer unit for a dual component development electrophotographic image forming device according to one example embodiment includes a housing having a reservoir for storing a developer mix that includes toner and magnetic carrier beads. An auger is positioned to convey developer mix in the reservoir toward the outer surface of a magnetic roll on a front of the housing. A ledge on an inner surface of the housing extends axially with respect to the magnetic roll along a front of the reservoir. The ledge is positioned upstream from a trim bar and downstream from a pickup pole of the magnetic roll with respect to the operative rotational direction of the magnetic roll. The ledge has a concave curved inner surface that is open to the reservoir and extends from near the trim bar to near a front side of the auger.

Trim bar entry geometry for a dual component development electrophotographic image forming device

A developer unit according to one example embodiment includes a housing having a reservoir for storing a developer mix that includes toner and magnetic carrier beads. A magnetic roll includes a stationary core and a sleeve positioned around the core that is rotatable relative to the core. The stationary core includes at least one permanent magnet having circumferentially spaced magnetic poles. An upper and a lower magnetically permeable metal shunt are positioned at each axial end of the magnetic roll. Each upper shunt and each lower shunt is positioned axially outboard of the core and in close proximity to the outer surface of the sleeve. A combination of the upper shunt and the lower shunt at each axial end of the magnetic roll surrounds greater than 180 degrees of the outer surface of the sleeve.

End sealing and magnetic field truncation of a magnetic roll of a dual electrophotographic image forming device

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Lexington, KY, United States of America

Elliott Vincent Jernigan