Browse Prior Art Database

ELECTROPHOTOGRAPHIC PRINTER PROCESS CONTROL WITH A BINARY ROS

IP.com Disclosure Number: IPCOM000025955D
Original Publication Date: 1989-Apr-30
Included in the Prior Art Database: 2004-Apr-04
Document File: 2 page(s) / 74K

Publishing Venue

Xerox Disclosure Journal

Abstract

In an electrophotographic printing machine employing a laser, there is a need to determine the shape of the photoreceptor photodischarge curve in order to facilitate process control setup. This curve is second order with respect to exposure. Therefore, a minimum of three points in the discharge voltage versus exposure space are required to specify the curve in a write-white or write-background system. These three points are typically the dark voltage, the background or full-discharge voltage and some intermediate point. In systems using a multilevel output ROS, this intermediate discharge level can be obtained by selecting one of the intermediate values needed for the process control setup. A laser raster output scanner (ROS) transforms a temporal modulation of input control voltage into a spatial modulation at the photoreceptor. The hotoreceptor integrates the energy deposited by the

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XEROX DISCLOSURE JOURNAL

ELE CTRO PHOTO G RA P HIC P RINTE R PROCESS CONTROL WITH A BINARY ROS Int. C1. G03g 15/01 David Birnbaum
Joel W. Grover
Larry A. Kovnat
Michael A. Parisi

Proposed Classification
U.S. C1.35514

In an electrophotographic printing machine employing a laser, there is a need to determine the shape of the photoreceptor photodischarge curve in order to facilitate process control setup. This curve is second order with respect to exposure. Therefore, a minimum of three points in the discharge voltage versus exposure space are required to specify the curve in a write-white or write-background system. These three points are typically the dark voltage, the background or full-discharge voltage and some intermediate point. In systems using a multilevel output ROS, this intermediate discharge level can be obtained by selecting one of the intermediate values needed for the process control setup. A laser raster output scanner (ROS) transforms a temporal modulation of input control voltage into a spatial modulation at the photoreceptor. The hotoreceptor integrates the energy deposited by the

rapid spatial variation in ROS intensity. As the spatial frequency of these variations increases, the photoreceptor is less able to follow the intensity variations. For example, if the spot size is adjusted to be that typically used for a 300 spi printer, then spatial variations at 600 spi are transmitted with only 10% efficiency. Higher frequency components are transmi...