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CYCLE-DOWN DARK DECAY AND REST RECOVERY COMPUTATION

IP.com Disclosure Number: IPCOM000027056D
Original Publication Date: 1995-Feb-28
Included in the Prior Art Database: 2004-Apr-07
Document File: 2 page(s) / 116K

Publishing Venue

Xerox Disclosure Journal

Abstract

The dark decay potential of an active matrix (AMAT) photoreceptor increases with successive cycles. For a fixed-grid charging method, this results in a lower dark-decay potential (VDDP) before development for each cycle. The term cycle-down is commonly used to describe this phenomenon. A rest period between jobs would allow the AMAT photoreceptor to recover and thereby have a lower dark-decay potential than before the rest period. Traditionally, a rest recovery table is employed to estimate the correction in VDDP after the rest period, and a concurrent process control correction is employed based upon the VDDP error for the previous cycle. Since the rest recovery table is only a function of rest time, lacking historical usage information, there is a potential for large error to arise under differing usage conditions. For example, the after-the-fact correction of process control based upon previous cycle error, and not on anticipated cycle-down, could result in a 1arge.error at the beginning few cycles when the cycle-down value is large for an aged photoreceptor. Accordingly, there is a need for a better VDDP control algorithm.

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XEROX DISCLOSURE JOURNAL

CYCLE-DOWN DARK DECAY AND REST RECOVERY COMPUTATION U.S. C1.355/219 Chi-chang Lu

Proposed Classification

Int. C1. G03g 15/02

The dark decay potential of an active matrix (AMAT) photoreceptor increases with successive cycles. For a fixed-grid charging method, this results in a lower dark-decay potential (VDDP) before development for each cycle. The term cycle-down is commonly used to describe this phenomenon. A rest period between jobs would allow the AMAT photoreceptor to recover and thereby have a lower dark-decay potential than before the rest period. Traditionally, a rest recovery table is employed to estimate the correction in VDDP after the rest period, and a concurrent process control correction is employed based upon the VDDP error for the previous cycle. Since the rest recovery table is only a function of rest time, lacking historical usage information, there is a potential for large error to arise under differing usage conditions. For example, the after-the-fact correction of process control based upon previous cycle error, and not on anticipated cycle-down, could result in a 1arge.error at the beginning few cycles when the cycle-down value is large for an aged photoreceptor. Accordingly, there is a need for a better VDDP control algorithm.

The present disclosure proposes to use a predetermined dark-decay potential history for an AMAT photoreceptor, along with an algorithm that represents its variation with cycled usage and rest, to predict the photoreceptor dark- decay and thereby provide a more accurate charge and bias levels during machine use. The process control may be implemented using a look-up table containin data indicating the dark-decay error and the necessary dissipation time as a f; unction of the cycle no. A portion of such a look-up table follows:

Cycle No. A Dark Decay (v) Dissipation Time (sec.)

1 10.0 7
2

3

4

0

0

0

20

21

0

0

0

1...