Photoconductor refreshing cycles

Patent metadata

Field	Value
Publication number	US-10739719-B2
Application number	US-201916437889-A
Country	US
Kind code	B2
Filing date	Jun 11, 2019
Priority date	Dec 22, 2015
Publication date	Aug 11, 2020
Grant date	Aug 11, 2020

Abstract

A photoconductive layer in an image forming apparatus is refreshed. A first refreshing cycle is performed, including applying, at a first refresh unit, a first refresh voltage to the photoconductive layer and applying, at a second refresh unit, a second refresh voltage to the photoconductive layer. A second refreshing cycle is performed, including applying, at the first refresh unit, a third refresh voltage to the photoconductive layer, the third refresh voltage being higher than the first refresh voltage and higher than the second refresh voltage. Each of the first and second refreshing cycles electrically bias the photoconductive layer to a refresh polarity opposite to a print polarity applied during a print routine of the image forming apparatus.

First claim

What is claimed is:

1. An image forming apparatus comprising:
a photoconductive layer;
a plurality of refresh units; and
a controller to control the refresh units to apply increasingly greater refresh voltages to the photoconductive layer over a plurality of refresh cycles to electrically bias the photoconductive layer to a refresh polarity opposite a print polarity to which the photoconductive layer is biased during a print routine of the image forming apparatus.

2. The image forming apparatus of claim 1 , wherein the refresh units comprise a first refresh unit and a second refresh unit that respectively apply a first refresh voltage and a second refresh voltage to the photoconductive layer during a first refresh cycle.

3. The image forming apparatus of claim 2 , wherein the first refresh voltage is greater than the second refresh voltage.

4. The image forming apparatus of claim 2 , wherein the first refresh unit applies a third refresh voltage to the photoconductive layer during a second refresh cycle after the first refresh cycle.

5. The image forming apparatus of claim 4 , wherein the third refresh voltage is greater than the first refresh voltage and the second refresh voltage.

6. The image forming apparatus of claim 1 , wherein the refresh units comprise a first refresh unit that applies a first refresh voltage to the photoconductive layer during a first refresh cycle and a third refresh voltage to the photoconductive layer during a second refresh cycle after the first refresh cycle.

7. The image forming apparatus of claim 6 , wherein the third refresh voltage is greater than the first refresh voltage.

8. The image forming apparatus of claim 6 , wherein the refresh units further comprise a second refresh unit that applies a second refresh voltage to the photoconductive layer during the first refresh cycle.

9. The image forming apparatus of claim 8 , wherein the second refresh voltage is less than the first refresh voltage.

10. The image forming apparatus of claim 1 , wherein the controller is to control the refresh units to electrically bias the photoconductive layer at the print polarity during the print routine of the image forming apparatus.

11. A method comprising:
during a first refresh cycle, applying, by a refresh unit of an image forming apparatus, a refresh voltage to a photoconductive layer of the image forming apparatus to electrically bias the photoconductive layer to a refresh polarity opposite a print polarity to which the photoconductive layer is biased during a print routine of the image forming apparatus; and
during a second refresh cycle after the first refresh cycle, applying, by the refresh unit, a different refresh voltage to the photoconductive layer to electrically bias the photoconductive layer to the refresh polarity.

12. The method of claim 11 , wherein the different refresh voltage is greater than the refresh voltage.

13. The method of claim 11 , wherein the refresh unit is a first refresh unit, the different refresh voltage is a third refresh voltage, and the method further comprises:
during the first refresh cycle, applying, by a second refresh unit of the image forming apparatus, a second refresh voltage to the photoconductive layer to electrically bias the photoconductive layer to the refresh polarity.

14. The method of claim 13 , wherein the second refresh voltage is less than the first refresh voltage.

15. The method of claim 14 , wherein the third refresh voltage is greater than the first refresh voltage and the second refresh voltage.

16. A non-transitory computer-readable data storage medium storing instructions executable by a processor to:
during a refresh cycle, cause a first refresh unit of an image forming apparatus to apply a first refresh voltage to a photoconductive layer of the image forming apparatus to electrically bias the photoconductive layer to a refresh polarity opposite a print polarity to which the photoconductive layer is biased during a print routine; and
during the refresh cycle, cause a second refresh unit of the image forming apparatus to apply a second refresh voltage to the photoconductive layer to electrically bias the photoconductive layer to the refresh polarity.

17. The non-transitory computer-readable data storage medium of claim 16 , wherein the second refresh voltage is less than the first refresh voltage.

18. The non-transitory computer-readable data storage medium of claim 16 , wherein the refresh cycle is a first refresh cycle, and the instructions are executable by the processor to further:
during a second refresh cycle after the first refresh cycle, cause the first refresh unit to apply a third refresh voltage to the photoconductive layer to electrically bias the photoconductive layer to the refresh polarity.

19. The non-transitory computer-readable data storage medium of claim 18 , wherein the second refresh voltage is less than the first refresh voltage.

20. The non-transitory computer-readable data storage medium of claim 19 , wherein the third refresh voltage is greater than the first refresh voltage and the second refresh voltage.

Assignees

• Hp Indigo Bv

Inventors

• Moalem Sasi
• Maister Dmitry
• Chang Seongsik
• Green Dekel

Classifications

• G03G21/0076

  Plural or sequential cleaning devices · CPC title

• G03G15/0266

  Arrangements for controlling the amount of charge · CPC title

• G03G21/0023

  with electric bias · CPC title

• G03G21/0094 Primary

  fatigue treatment of the photoconductor · CPC title