Browse Prior Art Database

PHOTOCONDUCTOR CHARGE MODULATION FOR ELECTROPHOTOGRAPHIC RANGE EXTENSION

IP.com Disclosure Number: IPCOM000023335D
Original Publication Date: 1977-Jun-30
Included in the Prior Art Database: 2004-Mar-30
Document File: 2 page(s) / 322K

Publishing Venue

Xerox Disclosure Journal

Abstract

It is well known in electrophotography that the introduction of a very fine spatially modulated charge pattern on the surface of the photoreceptor can be used to obtain improved solid area coverage, especially with development systems that only respond strongly to electrostatic fringe fields. In such a case, it is well known that the spatial charge modulation should have characteristics that favor the creation of fringe fields. Specifically, the profiles of the charge distribution should be sharp and possess as large a depth of modulation as possible. Although these conditions will improve the solid area coverage, we claim that they inherently yield poor tonal range in the final copies.

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XEROX DISCLOSURE JOURNAL

PHOTOCONDUCTOR CHARGE MODULATION Proposed Classification
FOR ELECTROPHOTOGRAPHIC RANGE U.S. Cl, 355/3
EXTENSION mt. Cl. G03g 15/00
C.F. Gallo
T.J, Hammond

It is well known in electrophotography that the introduction
of a very fine spatially modulated charge pattern on the
surface of the photoreceptor can be used to obtain improved
solid area coverage, especially with development systems that
only respond strongly to electrostatic fringe fields. In such
a case, it is well known that the spatial charge modulation
should have characteristics that favor the creation of fringe
fields. Specifically, the profiles of the charge distribution
should be sharp and possess as large a depth of modulation as
possible. Although these conditions will improve the solid
area coverage, we claim that they inherently yield poor tonal
range in the final copies.

It is not so well known that this photoreceptor charge mod-
ulation technique can also be used to obtain substantial
extension of the tonal range of the electrophotographic
copies, under the following conditions: (1) An electrophoto-
graphic development system with inherent solid area coverage
(e.g., magnetic brush, electroded cascade, etc.) must be used.
(2) The profiles of the spatial charge modulation should be
soft and smooth, (3) The depth of the spatial charge modula-
tion should be comparatively small. This synergistic combina-
tion of parameters maximizes the tonal range of the final
copies.

The above results are achieve...