IMAGING SYSTEM

1339905 Electro-photography XEROX CORP [21 Dec 1970 [30 Dec 1969] 60542/70 Heading G2H During cascade or magnetic brush development of a charge image on a photo-conductive surface/, using dry toner carrier developer carrier grit is selectively deposited on at least one adjacent non- imaging photo-conductive surface which is uniformly charged at a polarity opposite to that of the charge image. A shield is provided between the imaging and non-imaging surfaces (which may be integral or separate) during prior uniform charging and imagewise exposure to form the charge image. Each surface may be of a drum or web. A web may be uniformly charged on a feed roll before passage round a drum. After transfer of a developed image from a drum surface, the imaging and non-imaging surfaces are prepared for reuse by application of a reversed charge, brush cleaning and light exposure. After formation of a developed image and deposition of grit on a web containing both imaging and non- imaging surfaces, the latter are cut-off and discarded. A non-imaging web may be in the form of an endless belt. Fig.3 shows an integral drum having an imaging surface charged by device 21 and non-imaging surfaces charged by devices 31 and 31' before exposure, cascade development and brush cleaning, the surface being separated by shields 33 and 33'.