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ANNULAR ELECTRODE FOR USE IN AN OUT-OF-CONTACT ELECTROGRAPHIC SYSTEM

IP.com Disclosure Number: IPCOM000024382D
Original Publication Date: 1980-Jun-30
Included in the Prior Art Database: 2004-Apr-02
Document File: 2 page(s) / 96K

Publishing Venue

Xerox Disclosure Journal

Abstract

It has been observed that latent images formed by discharges from printheads 1 having well-polished electrodes 2 (Figure 1) frequently result in doughnut-shaped images. It is believedsuch images are created because with smooth electrodes, field emission, which provides the spark initiating electrons, is most likely to occur at the electrode edges 4 where field enhancement is significant. Furthermore, electrons emitted from the edges cannot cross the electric field lines 3 between the central regions 10 of the electrode 2 and the dielectric imaging material 12. Since the electrons cannot cross the field, no charge is deposited directly beneath the center 10 of the electrode 2.

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XEROX DISCLOSURE JOURNAL

ANNULAR ELECTRODE FOR USE IN AN OU T-OF-CONTACT ELEC TROGRAPHIC SYSTEM
Martin E. Banton

Proposed Classification
U.S. Cl. 358/295 Int. C1. H04n 1/024

FIG I

fIG2

It has been observed that latent images formed by discharges from printheads 1 having well-polished electrodes 2 (Figure 1) frequently result in doughnut-shaped images. It is believedsuch images are created because with smooth electrodes, field emission, which provides the spark initiating electrons, is most likely to occur at the electrode edges 4 where field enhancement is significant. Furthermore, electrons emitted from the edges cannot cross the electric field lines 3 between the central regions 10 of the electrode 2 and the dielectric imaging material 12. Since the electrons cannot cross the field, no charge is deposited directly beneath the center 10 of the electrode 2.

Volume 5 Number 3 May/June 1980 307

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ANNULAR ELECTRODE FOR USE IN AN OUT-OF-CONTACT ELECTROGRAPHIC SYSTEM (Cont'd)

To overcome the problem, a printhead 5 having an annular electrode 6 (Figure 2) is used. Electrode 6 has a generally cylindrical, hollow configuration with dielectric material in the electrode interior 7 and exterior 8. The surface resistivity of the interior dielectric material 7 is preferably higher than the surface resistivity of the exterior dielectric material 8.

With an annular electrode 6, electrons can follow field lines 3...