Browse Prior Art Database

ELECTROPHOTOGRAPHIC DEVICE WITH IMPROVED BEAD PICKOFF ARRANGEMENT

IP.com Disclosure Number: IPCOM000025911D
Original Publication Date: 1988-Dec-31
Included in the Prior Art Database: 2004-Apr-04
Document File: 4 page(s) / 241K

Publishing Venue

Xerox Disclosure Journal

Abstract

Developing material used in systems for developing latent images on a charge retentive surface often comprises a mixture of toner and a "carrier" of larger granular beads of a magnetic material. If the developing system is a magnetic brush, magnetizable carrier beads also provide mechanical control for the formation of magnetic brush bristles so that toner can readily be brought into contact with the charge retentive surface. Toner is attracted to the latent image from the carrier beads to form the toner image. In this type of system, some carrier beads inevitably adhere to the charge retentive surface after the image is developed. It is thus essential for optimum operation that carrier beads remaining on the charge retentive surface after development be removed therefrom.

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XEROX DISCLOSURE JOURNAL

ELECTROPHOTOGRAPHIC DEVICE Proposed Classification WITH IMPROVED BEAD PICKOFF
ARRANGE ME NT
Jeffrey J. Folkins
Morton Silverberg

U.S. Cl. 355/15 Int. C1. G03g 21/00

,116

4 f

112 -2

34 FIG. I -

-

Volume 13 Number 6 November/December 1988

4

i

C F/G. IA

325

[This page contains 1 picture or other non-text object]

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ELECTROPHOTOGRAPHIC DEVICE WITH IMPROVED BEAD PICKOFF ARRANGEMENT (Cont'd)

Developing material used in systems for developing latent images on a charge retentive surface often comprises a mixture of toner and a "carrier" of larger granular beads of a magnetic material. If the developing system is a magnetic brush, magnetizable carrier beads also provide mechanical control for the formation of magnetic brush bristles so that toner can readily be brought into contact with the charge retentive surface. Toner is attracted to the latent image from the carrier beads to form the toner image. In this type of system, some carrier beads inevitably adhere to the charge retentive surface after the image is developed. It is thus essential for optimum operation that carrier beads remaining on the charge retentive surface after development be removed therefrom.

With reference to Figure 1, an inventive bead pickoff device may be advantageously located within a developer station D. Exemplary developer housing 34 may be a container 100 for holding developer material therewithin, with magnetic brush roll 42 journaled for rotating movement within the container to carry developer mix in the container into contact with photoreceptor belt 10. In a preferred embodiment, developer housing 34 may be one of multiple developer housings movable into and out of developing position with respect to the photoreceptor, in accordance with the need to use the particular developer housing to develop the latent image, or a portion thereof. Container 100 extends across photoreceptor belt 10, transverse to the direction of travel 12 thereof, and is generally provided with upstream and downstream walls 102 and 104, respectiveIy. Along wall 104 on the downstream side of container 100, a permanent magnet member 106 is provided along the uppermost portion of wall 104, in close proximity to photoreceptor belt 10. Permanent magnet member 106 is preferably a permanent magnet member having a strength great enough to overcome the electrostatic force holding any carrier beads to photoreceptor belt 10 during development, and may have a generally pointed shape with point 108 at its most proximate to the photoreceptor to better focus the magnetic field at a bead removal point. Interposed between permanent magnet member 106 and photoreceptor belt 10 is located a bead catch 110, supported, for example, on the machine frame (not shown) and desirably a non-permanent magnetic material. Either a non-magnetic material, or a material magnetic only in the presence of another magnet, is suitable. In the described embodiment, permanent magnet member 10...