Cascade development station having a roughened development plate for

Abstract

A special inexpensive development electrode within a cascade development station is positioned closely adjacent to a xerographic drum to define a development zone therebetween. The electrode is roughened by producing deflection elements thereon forming a waffle-like or diamond-shaped knurled pattern projecting into the development zone, and, at the same time, is designed to be spaced from the drum by a distance which varies from between a relatively wide spacing adjacent the input end of the development zone and a relatively narrow spacing toward the output end of the zone. Together, the variable spacing of the zone and the deflection elements have the effect of increasing the density of the developer in the zone to thus decrease its velocity through the zone so that directional effects in developed images due to a high velocity differential between the developer and the drum can be controlled and substantially eliminated, while at the same time, introducing a radial component of motion to the developer toward the drum. These characteristics result in an increased number of development events, an increased quantity of toner within the development zone, more effective scavenging of toner from background portions of the drum and, in general, greater uniformity and speed in the development operation.