Development electrode system

Claim 1

In a xerographic developing apparatus of the type wherein a latent electrostatic image formed on a photoconductive surface rotated past processing stations in an uphill direction is developed and cleaned by cascading multi-component developer material including toner particles over the image bearing surface, an improved cleanup electrode member apparatus including electrode means including a development member and a cleanup member positioned in spaced parallel relation to said moving surface and said cleanup member being arranged adjacent to the upwardly moving developed image on said surface at the top of the development zone, a first source of electrical potential ranging from aBout 400 volts to about 600 volts coupled to said cleanup member of a polarity similar to the polarity of the latent image to attract developed material dislodged fron the developed surface by the flow of cascading developer material, a second source of electrical potential ranging from about 600 to about 1000 volts coupled to said cleanup member of a polarity opposite to the polarity of the latent image to repel developer material covering the cleanup member, and switching means for applying said first potential synchronous with development of image areas and said second potential synchronous with development of interdocument areas whereby accumulated toner particles on said cleanup member develop interdocument areas enabling high quality development of the image areas.