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US5523831A
Expired / Lapsed
US
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Accurate dynamic control of the potential on the photoconductor surface using an updatable look-up table
Assignee: Eastman Kodak Co
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Filing: 1994-03-17
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Granted: 1996-06-04
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Expires: 2014-03-17
Abstract
Abstract The voltages, V0, on a photoconductor surface are measured over a wide range of grid voltages, the results of which are stored in a look-up table Vgrid vs. V0. The updated Vgrid/V0 look-up table permits automatic and accurate adjustment of the primary charging step in the electrographic cycle. This method accommodates any number of desired V0 levels over a wide range of voltage. The present use establishes the relationship without going through a lengthy iterative procedure inherent in using feedback adjustment loops. The calibrated look-up table is updated as often as is required to compensate for such things as aging, wear, and environmental changes, to name a few. Calibration is repeated and the entire look-up table is updated after certain intervals of time or usage, or whenever drift is detected at even a single point of the Vgrid to V0 relationship. This compensates for the variability of corona charging over time as well as over a range of V0's.
Inventors
- 👤 Allen J. Rushing
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 16:18
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/02; G03G15/0266; G03G15/0291
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
139 words
A corona charging apparatus for providing a charge on a surface of an image-forming member, said apparatus, comprising: a primary corona charger for applying a voltage to the surface; a variable power supply for varying the voltage on said primary corona charger; an electrometer for measuring the voltage on the photoconductive surface; means for accessing a look-up table containing a charger voltage that corresponds to a desired voltage on the surface of the image-forming member; means for adjusting the variable power supply to obtain a voltage on the primary corona charger that will result in the desired corresponding voltage on the surface according to the look-up table; and means for providing a calibration cycle to update the look-up table when the voltage on the surface differs by a predetermined amount from the predicted voltage supplied by the look-up table.
Claim 2
Dependent Claim
139 words
A corona charging apparatus for providing a charge on a surface of an image-forming member, said apparatus, comprising: a primary corona charger for applying a voltage to the surface; a variable power supply for varying the voltage on said primary corona charger; an electrometer for measuring the voltage on the photoconductive surface; means for accessing a look-up table containing a charger voltage that corresponds to a desired voltage on the surface of the image-forming member; means for adjusting the variable power supply to obtain a voltage on the primary corona charger that will result in the desired corresponding voltage on the surface according to the look-up table; and means for providing a calibration cycle to update the look-up table when the voltage on the surface differs by a predetermined amount from the predicted voltage supplied by the look-up table.
Claim 3
Dependent Claim
19 words
An apparatus as set forth in claim 1 wherein the means for accessing the look-up table is a microcomputer.
Claim 4
Dependent Claim
20 words
An apparatus as set forth in claim 2 and including means for updating said look-up table on a periodic basis.
Claim 5
Dependent Claim
27 words
An apparatus as set forth in claim 2 and including means for providing a calibration cycle to update the look-up table whenever the apparatus is turned on.
Claim 6
Dependent Claim
34 words
An apparatus as set forth in claim 2 and including environmental sensors for generating signals representing environmental conditions; and means responsive to said signals for providing a calibration cycle to update the look-up table.
Claim 7
Dependent Claim
41 words
An apparatus as set forth in claim 5 wherein the environmental sensor detects humidity and wherein said means for providing a calibration cycle provides said calibration cycle to update the look-up table when a sensor detects a change in relative humidity.
Claim 8
Independent Claim
117 words
A method of controlling the voltage on a photoconductive surface of an image-forming member, comprising the steps of: controlling the voltage on the photoconductive surface using a primary corona charger; accessing a look-up table with a desired voltage for the photoconductive surface to determine the voltage to be applied to the primary corona charger; adjusting the voltage to the primary corona charger to a new setting in accordance with the value obtained in the look-up table to obtain the desired voltage on the photoconductive surface; and providing a calibration cycle to update the look-up table when the measured voltage on the photoconductive surface differs by a predetermined amount from the predicted voltage supplied by the look-up table.
Claim 9
Independent Claim
117 words
A method of controlling the voltage on a photoconductive surface of an image-forming member, comprising the steps of: controlling the voltage on the photoconductive surface using a primary corona charger; accessing a look-up table with a desired voltage for the photoconductive surface to determine the voltage to be applied to the primary corona charger; adjusting the voltage to the primary corona charger to a new setting in accordance with the value obtained in the look-up table to obtain the desired voltage on the photoconductive surface; and providing a calibration cycle to update the look-up table when the measured voltage on the photoconductive surface differs by a predetermined amount from the predicted voltage supplied by the look-up table.
Claim 10
Dependent Claim
21 words
The method as set forth in claim 7 wherein the values in the look-up table are updated on a periodic basis.
Claim 11
Dependent Claim
59 words
The method as set forth in claim 8 wherein the updating of values in the look-up table is accomplished by stepping the voltage V grid on a corona charger grid through a series of values, and measuring the corresponding voltage V 0 on the photoconductive surface and storing the corresponding V grid /V 0 pairs in the look-up table.
Claim 12
Dependent Claim
25 words
The method as set forth in claim 7 wherein a calibration cycle to update the look-up table is initiated when the machine is powered up.
Claim 13
Dependent Claim
22 words
The method as set forth in claim 7 wherein a calibration cycle to update the look-up table is initiated by environmental sensors.
Claim 14
Dependent Claim
28 words
The method as set forth in claim 11 wherein a calibration cycle to update the look-up table is initiated when a sensor detects a change in relative humidity.
Claim 15
Dependent Claim
29 words
The method of claim 7 and wherein adjusting of voltage to the primary charger is provided to a control grid that controls a flow of emissions from corona wires.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-06-04 | 1999-12-04 | 2000-06-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-06-04 | 2003-12-04 | 2004-06-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-06-04 | 2007-12-04 | 2008-06-04 | $7700.00 | Window Closed / Lapsed |