Xerox Corporation

Ronald E Shaul

Stanley John Wallace

David Mark Kerxhalli

Brian Robert Conrow

Frederick Allen Donahue

Jack Beery

Mark Andrew Omelchenko

Joseph W Ward

Joseph A Mastrandrea

Robert M Mara

Rosario A Bracco

Daniel R Maurer

Olga Y Ramirez

Cathleen J Raker

Raymond L Mongeon

Patrick O Waller

Patricia A Papaleo

Colleen Tremaine

Sue K Lam-Chon

In color printing with a color registration system for the registration of plural color images on an image bearing surface, such as a photoreceptor belt of a color printer, registration marks are imaged on the image bearing surface, which registration marks correspond to the color images and are sensed by a registration marks sensor. In an initial gross registration mode the system first automatically images first registration marks, in the form of expanded chevron targets, which are greatly expanded in the process direction so as to avoid overlapping marks even if there is initial gross misregistration, to thus provide wider initial misregistration latitude for the sensor. When an acceptable initial registration is achieved, the system automatically switches to imaging more closely spaced and more frequent second registration marks, preferably regular chevron targets, providing higher registration accuracy. These registration targets may be generated along opposite sides of the image areas, on opposite sides of the photoreceptor or other image bearing surface in the process direction.

Color printing process direction color registration system with expanded chevrons

There is provided a method for use with a printing machine having a movable imaging member and a projecting system for modulating a beam and projecting an image into the movable imaging member. The printing machine further includes a developer for application of developer material to the image projected onto the movable imaging member for transfer of the image to a print media sheet. The method, which is intended for use in controlling exposure of a test patch on the movable imaging member includes the steps of: a) providing a time-keeping device with the time-keeping device including a variable value which is either incrementable or decrementable; b) detecting a signal indicating that the movable imaging member is positioned relative to the beam in a selected orientation, wherein the movable imaging member passes by the beam at a selected speed; c) providing a reference value with the reference value varying as a function of the selected speed; d) in response to the detecting of (b), modulating the beam, relative to the movable imaging member, so as to expose a portion for the test patch; e) concurrent with the modulating of (d), incrementing or decrementing the variable value of the time keeping device; and f) repeating said modulating of (d) until the value of the variable value is about equal to the reference value and the test patch is exposed.

Control system for test patch area exposure in a printing machine

A sheet detector having an emitter (lamp), detector (phototransistor), operational amplifier and an RC network. As contamination is deposited on the emitter or detector, a feedback loop provides more drive to the lamp providing sufficient drive to hold the emitter of the phototransistor at its desired stage. As a first copy paper is passed between the emitter and detector, the RC network of a common mode operational amplifier detects a change and generates an output. As a subsequent sheet enters the system, the transmissibility abruptly changes again causing the common mode operational amplifier to provide a subsequent pulse indicating the presence of a multiple feed.

Multiple copy and transparency detector with illumination control

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Bloomfield, NY, United States of America

Ronald E Shaul