Xerox Corporation

James M Hardenbrook

Paul G Andrus

Osmar A Ullrich

An electrostatic latent image residing on an electrically insulating surface used to induce a similar image on a sectionally conductive member by bringing one surface of the sectionally conductive member into proximity with the latent image while the opposite surface of the sectionally conductive member is brought to ground potential. The sectionally conductive member is then removed from proximity with the latent image. To prevent electrical breakdown during removal, a grounded electrode is placed adjacent the surface of the sectionally conductive member opposite the latent image but separated from the sectionally conductive member by a thin electrically insulating layer. A latent image is thus formed on the sectionally conductive member which can be developed by conventional means such as with electroscopic materials well known in the xerographic art.

Apparatus for inducing an electrostatic image in a conductive member

Method for inducing an electrostatic image in a conductive member

In an electrostatographic imaging apparatus, comprising, an imaging member with a surface capable of retaining an electrostatic latent image, a donor member with a surface capable of supporting a layer of particulate image-developing material, and means for maintaining the surface of said donor member in close proximity to the surface of said imaging member, the improvement which comprises a donor member having permanently disposed on its surface a plurality of raised, granular elements for self-spacing the donor member from the imaging member.

Transfer development apparatus using self-spacing donor member

Electrostatic imaging apparatus for transfer development of latent images employing a developer donor member with a plurality of raised micro-pins on the donor surface, for self-spacing the donor from the imaging surface. Methods of producing such donors are disclosed.

Method of making a donor member mold

Feedback circuit for the probe of an d.c. type electrostatic voltmeter to reduce spacing sensitivity thereof. A variable gain amplifier is employed to control the amplitude of the a.c. signal output of a square wave oscillator in response to the potential sensed by the probe. The a.c. signal output drives a high voltage transformer, the output of which is rectified to provide a d.c. signal output matching the potential sensed by the probe. The d.c. output is returned to the probe housing to bias the housing to a potential equal to the potential read by the probe. A sample and hold circuit enables readout of the d.c. signal output.

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Columbus, OH, United States of America

James M Hardenbrook