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PHOTORECEPTOR CHARGING SCOROTRON

IP.com Disclosure Number: IPCOM000025436D
Original Publication Date: 1985-Jun-30
Included in the Prior Art Database: 2004-Apr-04
Document File: 4 page(s) / 148K

Publishing Venue

Xerox Disclosure Journal

Abstract

Typically, in xerographic type copying machines, the entire width of the photoreceptor is charged preparatory to imaging. In many applications and uses, however, the latent image formed on the photoreceptor is smaller, leaving a charged but unused non-image area. Usually, this occurs when the machine is operated in a reduction mode, or in an open platen mode when the original does not cover the available image area. If left unattended, this fully charged non-imaged area will, because of the high charge state, develop out heavily with consequent rapid reduction of the machine toner supply. Alternately, means such as a fadeout lamp must be employed to erase the charge from this unused area of the photoreceptor before development.

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Volume 10 Number 3 May/June 1985 139

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PHOTORECEPTOR CHARGING SCOROTRON (Cont'd)

XEROX I40 DISCLOSURE JOURNAL

Volume 10 Number 3 May/June 1985

[This page contains 1 picture or other non-text object]

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PHOTORECEPTOR CHARGING SCOROTRON (Cont'd)

Typically, in xerographic type copying machines, the entire width of the photoreceptor is charged preparatory to imaging. In many applications and uses, however, the latent image formed on the photoreceptor is smaller, leaving a charged but unused non-image area. Usually, this occurs when the machine is operated in a reduction mode, or in an open platen mode when the original does not cover the available image area. If left unattended, this fully charged non- imaged area will, because of the high charge state, develop out heavily with consequent rapid reduction of the machine toner supply. Alternately, means such as a fadeout lamp must be employed to erase the charge from this unused area of the photoreceptor before development.

' To avoid or reduce the creation of charged but unused areas, a segmented charge scorotron 5 for charging the photoreceptor of an electrostatic type copying machine in preparation for imaging is shown in Figure 1. Scorotron 5 has an elongated U-shaped base 6 with a corona discharge wire 7 passing from an electrical contact post 8 at one end to an insulated post 8' at the opposite end and back again. Contact post 8 is connected to a high voltage power supply 13. A grid 10 fits over and interlocks with base 6, grid 10 controlling the emission of electrons from wire 7. Grid 10 is separated into individual grid segments 12a, 12b, and 12c, the axial length of grid segment 12a being chosen to charge a photoreceptor width corresponding to the image size for the smallest copy sheet handled by the machine. Grid segment 12b has a width such that when added to segment 12a, a photoreceptor width corresponding to the image size for the intermediate size copy sheet is charged while grid segment 12c has a width such that when added to the segments 12a and 12b, the entire operating width of the photoreceptor, which corresponds to the image size for the largest copy sheet, is charged. Grid segment 12a is co...