Browse Prior Art Database

MAGNETIC BRUSH DEVELOPMENT

IP.com Disclosure Number: IPCOM000024157D
Original Publication Date: 1979-Oct-31
Included in the Prior Art Database: 2004-Apr-02
Document File: 2 page(s) / 237K

Publishing Venue

Xerox Disclosure Journal

Abstract

Frequently, images are developed by magnetic brush rollers that have quality defects comprising small non-uniformities in the developed density. These non-uniformities are described as "bristle marks," The isodensity contours lie predominantly parallel to the process direction, density being modulated across the

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XEROX DISCLOSURE JOURNAL

MAGNETIC BRUSH DEVELOPMENT Proposed Classification
D. Dayton U.S. Cl. 427/145

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Witte Tnt. CL B41m 5/16

Frequently, images are developed by magnetic brush rollers that have quality defects comprising small non-uniformities in the developed density. These non- uniformities are described as "bristle marks," The isodensity contours lie predominantly parallel to the process direction, density being modulated across the process direction. The severity of the bristle marks is known from experiment to increase as the speed of the magnetic brush rollers increases. To reduce the bristle marks, the energy of the bristle tip striking the photoconductive surface must be reduced. This may be achieved by reducing the roll speed which, in turn, reduces the developed flux and lowers the amount of toner particles available for development. This technique unfavorably affects development. However, the magnetic fields of the magnetic brush developer roller may be designed to erect or nearly erect the brush bristles before they enter into the development nip, thereby reducing the velocity of the bristle tips in the nip. This reduces the energy of the bristle tips striking the photoconductive surface without requiring any reduction in roll speed. The condition of erect or nearly erect bristles entering the development nip can be achieved by properly locating magnet 10 inside non-magnetic, tubular member 12, As shown, the magnet may preferably be rotated an ang...