Patent ID: 8155571

Claim:
A developing roller for providing a magnetic brush for an electrostatic printer or copier, said developing roller comprising: a non-magnetic steel sleeve with a substantially cylindrical outer surface having processed areas with material removed and unprocessed areas without material removed, at least part of said processed areas with material removed of said substantially cylindrical outer surface including a regular or irregular array of a number of neighbouring isolated areas, each said isolated area having a recess in said substantially cylindrical outer surface, each said recess completely surrounded on all sides and isolated from neighbouring isolated areas by separation zones, wherein said separation zones form part of said unprocessed areas without material removed of said substantially cylindrical outer surface such that said separation zones provide a substantially consistent surface topology at the substantially cylindrical outer surface of said developing roller, wherein both the surface of processed areas with material removed and the surface of unprocessed areas without material removed is non-magnetic steel.