Granted Patent B2

US 8,837,967 · App. 12/842,834 · Granted Sep 16, 2014

Abstract

Claims (79)

1. A method for determining and applying a transfer voltage for use in an imaging apparatus having a member bearing a toner image, a transfer roller positioned adjacent to the member forming a transfer nip therewith, the method comprising:

detecting a condition associated with an imaging apparatus;

determining a servo voltage to be applied to the transfer roller during a transfer servo operation, the determining being based on the condition detected, the servo voltage being determined prior to a voltage being applied to the transfer roller during the transfer servo operation;

applying the servo voltage to the transfer roller and measuring a servo current in the transfer nip;

determining a transfer voltage based on the servo current;

applying the transfer voltage to the transfer roller during an image transfer operation by the imaging apparatus;

measuring transfer current in the transfer nip during one or more inter-page gaps of the image transfer operation; and

adjusting the transfer voltage based upon the measured transfer current to create an adjusted transfer voltage.

2. The method of claim 1 , wherein the member comprises a photoconductive surface and the applying the servo voltage and the measuring the servo current are done with the photoconductor surface charged to a printing voltage.

3. The method of claim 1 , wherein the transfer voltage is determined based upon a previously measured transfer current.

4. The method of claim 1 , further comprising deciding, following the determining the servo voltage, whether a new transfer voltage is to be determined.

5. The method of claim 4 , wherein the deciding comprises comparing the determined servo voltage with a previously determined servo voltage.

6. The method of claim 4 , wherein the deciding is based upon at least one of an occurrence of a power-on-reset operation by the imaging apparatus, a cover of the imaging apparatus being opened and the imaging apparatus substantially continuously printing for at least a predetermined period of time.

7. The method of claim 1 , further comprising, during an inter-page gap of the image transfer operation, changing the applied transfer voltage to an inter-page gap voltage to produce a current in the transfer nip during the inter-page gap that is substantially the same as the transfer current when a sheet of paper is in the transfer nip.

8. The method of claim 1 , wherein the transfer current measured comprises a plurality of transfer current measurements and the adjusted transfer voltage is based upon an average of the transfer current measurements.

9. The method of claim 1 , wherein the transfer current measured comprises a plurality of transfer current measurements and the adjusted transfer voltage is based upon a running average of the transfer current measurements.

10. An imaging device, comprising:

a member bearing a toner image;

a transfer roller positioned adjacent to the member forming a transfer nip therewith;

a voltage generator disposed proximally to the transfer roller for applying a voltage thereto; and

a controller communicatively coupled to the member, the transfer roller, and the voltage generator, for transferring the toner image from the member to a recording medium, the controller executing instructions for:

detecting a condition within the imaging device;

determining a servo voltage based on the detected condition;

controlling the voltage generator to apply the servo voltage to the transfer roller and measuring a servo current, the servo voltage being the only voltage applied to the transfer roller during a transfer servo operation;

determining a transfer voltage based on the servo current measured;

applying the transfer voltage to the transfer roller during an image transfer operation;

measuring transfer current in the transfer nip during one or more inter-page gaps of the image transfer operation; and

adjusting the transfer voltage based upon the measured transfer current to create an adjusted transfer voltage.

11. The device of claim 10 , wherein the member comprises a photoconductive drum and the voltage generator applies a charge to the photoconductive drum surface corresponding to a printing voltage when the servo voltage is applied to the transfer roller.

12. The device of claim 10 , wherein the controller determines the transfer voltage based upon a previously measured transfer current.

13. The device of claim 10 , wherein the controller decides, following the determining the servo voltage, whether a new servo voltage is to be determined.

14. The device of claim 13 , wherein the controller decides whether a new transfer voltage is to be determined in part by comparing the determined servo voltage with a previously determined servo voltage.

15. The device of claim 13 , wherein the controller decides whether a new servo voltage is to be determined in part based upon at least one of an occurrence of a power-on-reset operation by the imaging apparatus, a cover of the imaging device being opened and the imaging device substantially continuously printing for at least a predetermined period of time.

16. The device of claim 10 , wherein during an inter-page gap, the controller controls the voltage generator to change the applied transfer voltage to a predetermined inter-page gap voltage to produce a current in the transfer nip during the inter-page gap that is substantially the same as the transfer current when a sheet of media is in the transfer nip.

17. The device of claim 10 , wherein the transfer current measured comprises a plurality of transfer current measurements and the adjusted transfer voltage is based upon at least one of an average of the transfer current measurements and a running average thereof.

18. An imaging device, comprising:

a member bearing a toner image;

a transfer roller positioned adjacent to the member forming a transfer nip therewith;

a voltage generator disposed proximally to the transfer roller for applying a voltage thereto; and

a controller communicatively coupled to the member, the transfer roller and the voltage generator for transferring the toner image from the member to a recording medium, the controller executing instructions for:

determining a servo voltage for performing a transfer servo operation;

determining whether a new transfer servo operation is to be performed, comprising comparing the determined servo voltage with a servo voltage used in the last transfer servo operation;

upon an affirmative determination that a new transfer servo operation is to be performed, controlling the voltage generator to apply the determined servo voltage to the transfer roller and measure a servo current;

determining a transfer voltage based on the servo current measured; and

applying the transfer voltage to the transfer roller during an image transfer operation.

19. The imaging device of claim 18 , wherein the member comprises a photoconductive drum and the controller controls the voltage generator to apply a charge to the photoconductive drum surface corresponding to a printing voltage prior to the servo voltage being applied to the transfer roller.

20. The imaging device of claim 18 , wherein the controller executes instructions for measuring a transfer current during one or more inter-page gaps of the image transfer operation, and adjusting the transfer voltage based upon the measured transfer current.

21. The imaging device of claim 18 , wherein the controller determines the servo voltage based upon an environmental condition under which the imaging device is operating.

22. The method of claim 1 , wherein determining the servo voltage comprises calculating the servo voltage based upon the detected condition.

23. The method of claim 22 , wherein the servo voltage is calculated based upon one or more of print speed, media type and whether the image transfer operation corresponds to a simplex or duplex print operation.

24. The device of claim 10 , wherein the instructions for determining the servo voltage comprise instructions for calculating the servo voltage based upon the detected condition.

25. The device of claim 24 , wherein the servo voltage is calculated based upon one or more of print speed, media type and whether the image transfer operation corresponds to a simplex or duplex print operation.

26. The method of claim 1 , wherein the servo voltage is the only voltage applied to the transfer roller during the transfer servo operation.

27. The device of claim 10 , wherein the servo voltage is determined prior to a voltage being applied to the transfer roller during the transfer servo operation.

28. The device of claim 18 , wherein the servo voltage is determined prior to a voltage being applied to the transfer roller during the transfer servo operation.

29. The device of claim 18 , wherein the servo voltage is the only voltage applied to the transfer roller during the transfer servo operation.

30. A method for determining and applying a transfer voltage for use in an imaging apparatus having a member bearing a toner image, a transfer roller positioned adjacent to the member forming a transfer nip therewith, the method comprising:

detecting a condition associated with an imaging apparatus;

determining a servo voltage based on the condition detected;

applying the servo voltage to the transfer roller and measuring a servo current in the transfer nip;

determining a transfer voltage based on the servo current;

applying the transfer voltage to the transfer roller during an image transfer operation by the imaging apparatus;

measuring transfer current in the transfer nip during one or more inter-page gaps of the image transfer operation; and

adjusting the transfer voltage based upon the measured transfer current to create an adjusted transfer voltage,

wherein the transfer current measured comprises a plurality of transfer current measurements and the adjusted transfer voltage is based upon an average of the transfer current measurements.

31. The method of claim 30 , wherein the average is a running average of the transfer current measurements.

32. An imaging device, comprising:

a member bearing a toner image;

a transfer roller positioned adjacent to the member forming a transfer nip therewith;

a voltage generator disposed proximally to the transfer roller for applying a voltage thereto; and

a controller communicatively coupled to the member, the transfer roller, and the voltage generator, for transferring the toner image from the member to a recording medium, the controller executing instructions for:

detecting a condition within the imaging device;

determining a servo voltage based on the detected condition;

controlling the voltage generator to apply the servo voltage to the transfer roller and measuring a servo current;

determining a transfer voltage based on the servo current measured;

applying the transfer voltage to the transfer roller during an image transfer operation;

measuring transfer current in the transfer nip during one or more inter-page gaps of the image transfer operation; and

adjusting the transfer voltage based upon the measured transfer current to create an adjusted transfer voltage,

wherein the transfer current measured comprises a plurality of transfer current measurements and the adjusted transfer voltage is based upon at least one of an average of the transfer current measurements and a running average thereof.

Assignments (8)