Xerox Corporation

Joannes N De Jong

Vittorio R Castelli

Lloyd A Williams

James M Casella

Barry M Wolf

Harold M Anderson

Aron Sereny

A detection system includes a marking device for applying to a process medium a first chevron from a first printer, a second chevron from a second printer and a third chevron from both the first printer and the second printer, the third chevron having a first element applied from the first printer and a second element applied from the second printer. The detection system further includes a detection device for detecting a matrix of times including three pluralities of times, each of the three pluralities of times corresponding to a respective time of passage of the first, second and third chevrons by the detection device. The detection system further includes a determining device for determining the alignment error based on a function of the three pluralities of times. A control system includes a marking device for applying to a process medium a first chevron from a first printer, a second chevron from a second printer and a third chevron from both the first printer and the second printer. The control system further includes a detection device for detecting a matrix of times including three pluralities of times, each of the three pluralities of times corresponding to a time of passage of a respective one of the first, second and third chevrons by the detection device, a determining device for determining an alignment error based on a function of the matrix of times, and a control device for minimizing the alignment error.

Method and apparatus for correction of color registration errors

An encoder interface for interfacing an encoder having a first part defining a first axis to a structure having a second part defining a second axis substantially parallel to the first axis includes a portion for translating the first part with respect to the second part in a direction transverse to the first axis and a portion for rigidly rotationally stabilizing the first part with respect to the second part against a rotation of the first part about the first axis induced by a translation of the first part with respect to the second part in the direction transverse to the first axis. A method for interfacing an encoder having a first part defining a first axis with a structure having a second part defining a second axis substantially parallel to the first axis includes the steps of translating the first part with respect to the second part in a direction transverse to the first axis and rigidly rotationally stabilizing the first part with respect to the second part against a rotation of the first part about the first axis induced by a translation of the first part with respect to the second part in the direction transverse to the first axis.

Method and apparatus for antirotation encoder interfaces

A method and apparatus provides on-line calibration of low cost encoders by interfacing an encoder with a microprocessor and driving a shaft to which the encoder is attached at a slow constant speed and at a fast constant speed. Data is collected by the microprocessor for the slow and fast speeds and a mathematical analysis is performed which determines the torque disturbances occurring at each point in the rotational cycle of the shaft and which further determines the actual location of each encoder line on the encoder in the rotational cycle of the shaft. By knowing the actual location of each encoder line and the number of counts between encoder lines for a given speed, a high accuracy encoder can be realized at a minimal cost.

Automatic encoder calibration

A system for maintaining a uniform velocity of a belt which is driven on rollers. A first roller is provided with a first encoder which supplies a pulse train to a first control device which controls a first servomotor. The first servomotor drives the first roller which provides torque to the belt. A second roller is provided with a second encoder which supplies a pulse train to a second control device which controls a second servomotor for selectively dampening the second roller. When a variation in the speed of the belt is detected by the second control device a signal is sent from the second control device to the second servomotor. The second servomotor dampens any speed variations so that the belt maintains a constant speed at a location proximate to the second roller.

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Suffern, NY, United States of America

Joannes N De Jong