Coulter Information Systems, Inc.

Peter Guy Talmage

Manfred R Kuehnle

A method of and apparatus for toning an exposed electrophotographic member in a camera or other electrostatic imaging device which uses liquid toner comprising toner particles suspended in a dispersant. The method contemplates running the liquid toner into a chamber containing the photoconductive surface of the electrophotographic member and a metal plate parallel with one another and spaced apart as two boundaries of the chamber. During the toning operation, a low d.c. bias is applied across the chamber between the photoconductive surface and the plate of a polarity opposite to that characterizing the latent image such as to repel toner particles from the photoconductive surface, but the voltage of the bias is low enough not to affect increments of the surface which have substantial charge on them. The result is that said increments with very little charge are left with practically no adhering particles. When the toning is completed, the bias is substantially increased to cause strong attraction to the plate so that any particles floating in the liquid toner which have not adhered to the photoconductive surface tend to collect on the plate. Since the other particles have adhered to the latent image on the photoconductive surface, the toner is cleared of floating particles and can be run out of the chamber leaving the toned image clean of particles in the untoned so called background areas.

Method of and apparatus for toning electrophotographic film

A method for charging an electrophotographic imaging surface includes the steps of reciprocating at least one longitudinally disposed corona electrode along the longitudinal axis and simultaneously applying a corona voltage to the electrode for developing a corona so that a substantially uniform corona charge is applied to the entire electrophotographic imaging surface. An additional step, performed simultaneously with production of the corona and reciprocation of the electrode can be the movement of one of the electrodes or the electrophotographic imaging surface relative to the other. Apparatus employed to perform this method also is disclosed.

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Lexington, MA, United States of America

Peter Guy Talmage