MAGNET FOR TONER CONTAMINATION CONTROL
Original Publication Date: 1986-Feb-28
Included in the Prior Art Database: 2004-Apr-04
Xerox Disclosure Journal
In an electrophotographic printing machine, an electrostatic latent image IS recorded on a photoconductive member maybe a moving belt or drum which advances to the development station. Preferably, the development station employs a magnetic brush development system. The magnetic brush development system includes a housing having magnetic brush transport roll disposed therein and adapted to advance toner particles to the latent image recorded on the photoconductive member. In the development housing, there are two areas, one on each end of the magnetic brush transport roll, where clearance must be provided between the housing walls and the rotating magnetic brush roll. As a result of this clearance, an opening exists at each end of the roll through which toner particles may escape from the housing into the printing machine contaminating other subsystems thereof. Magnets may be positioned under the trim bar at the ends of the magnetic brush roll. Each magnet has a North and South pole having a strength of about 450 gauss. The magnets form a chain of carrier granules that effectively close the gap between the moving roll and the housing in this region and significantly reduce toner contamination, A magnetic seal of this type does not affect the relatlve motion between the housing and roll while still restricting the toner laden air from flowing outwardly from the housing.