Method and apparatus for using vibratory energy with application of transfer field for enhanced transfer in electrophotographic imaging

• US 5,016,055 A
• Filed: 07/02/1990
• Issued: 05/14/1991
• Est. Priority Date: 07/02/1990
• Status: Expired due to Term

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: Radulski, Charles A., Pietrowski, Kenneth W.
• Primary Examiner(s): Grimley, A. T.
• Assistant Examiner(s): BRASE, SANDRA L
• Application Number:
  US07/548,351
• Time in Patent Office: 316 Days
• Field of Search: 134/1, 73/862.59, 355/271, 355/273, 355/296, 118/652, 310/325, 310/323
• US Class Current: 399/390
• CPC Class Codes: G03G 15/16 of a toner pattern, e.g. a powder pattern , e.g. magnetic transfer

Abstract

An electrophotographic device includes a flexible belt-type charge retentive member, bearing a developed latent image and brings a sheet of paper or other transfer member into intimate contact with the charge retentive surface at a transfer station for electrostatic transfer of toner from the charge retentive surface to the sheet. At the transfer station, a resonator suitable for generating vibratory energy is arranged in line contact with the back side of the charge retentive, to uniformly apply vibratory energy to the charge retentive member surface at a position opposite the transfer coronode or peak transfer field, or slightly upstream therefrom. Toner is released from the electrostatic and mechanical forces adjering it to the charge retentive surface at the line contact position.

Claims

1. In an imaging device having a non-rigid member with a first charge retentive surface, moving in a process direction along an endless path, means for producing a toner image on the charge retentive surface, corona transfer device, having at least a first coronode driven with a relatively high voltage to a corona producing condition for providing non-contacting electrostatic transfer of the developed toner image within a transfer field to a second surface in contact with said charge retentive surface, said coronode supported within said corotron arranged generally, parallel to said charge retentive surface and transverse to the direction of movement thereof, and means for enhancing transfer of said developed image to said second surface across areas of less than optimal contact said transfer enhancing means including:

vibratory energy producing means, mechanically coupled in line contact with a second surface of said non-rigid member, applying vibratory energy enabling toner release from the charge retentive surface, at a position prior to and near, or opposite, the region where the transfer field is approaching its peak value.

2. The device as defined in claim 1 wherein said vibratory energy producing means includes a piezoelectric device excited by an A.C. voltage supply.

3. The device as defined in claim 2 wherein A.C. voltage supply is driven at a frequency in the range of 20 kHz to 200 kHz.

4. The device as defined in claim 2 wherein said piezoelectric device is excited to produce an output in the range of 20 kHz to 200 KHz.

5. In an imaging device having a non-rigid member moving in a process direction along an endless path having a first charge retentive surface, means for producing a toner image on the charge retentive surface, a corona transfer device having at least a first coronode driven with a relatively high voltage to a corona producing condition for providing non-contacting electrostatic transfer of the developed toner image within a transfer field to a second surface in contact with said charge retentive surface, said coronode supported within said corotron generally parallel to said charge retentive surface and transverse to the direction of movement thereof, and means for enhancing transfer of said developed image to said second surface, said transfer enhancing means including:

vibratory energy producing means, mechanically coupled in line contact with a second surface of said non-rigid member, applying vibratory energy enabling toner release from the charge retentive surface, at a position slightly upstream from the coronode, in a direction opposite to the process direction.

6. The device as defined in claim 5 wherein said vibratory energy producing means is arranged within the transfer field of the transfer corona generator and within 10 mm upstream in a direction opposite to the process direction, from the coronode.

7. The device as defined in claim 5 wherein said vibratory energy producing means includes a piezoelectric device excited by an A.C. voltage supply.

8. The device as defined in claim 7 wherein A.C. voltage supply is driven at a frequency in the range of 20 kHz to 200 kHz.

9. The device as defined in claim 7 wherein said piezoelectric device is excited to produce an output in the range of 20 kHz to 200 kHz.

10. In an imaging device having a non-rigid member with a charge retentive surface moving in a process direction along an endless path, means for creating a latent image on the charge retentive surface, means for developing the latent image with toner, said toner held on said charge retentive surface by electrostatic and mechanical forces, a transfer corona generator having at least a first coronode driven with a relatively high voltage to a corona producing condition for providing electrostatic non-contacting transfer of the developed toner image to a second surface brought into contact with the charge retentive surface, said coronode supported within said corotron and arranged generally parallel to said charge retentive surface and transversely across the direction of movement thereof, and means for enhancing electrostatic transfer of said developed image to said copy sheet, said transfer enhancing means comprising:

a resonator to apply relatively high frequency vibratory energy sufficient to mechanically release said toner from said electrostatic and mechanical forces, arranged in line contact with the non-rigid member, transverse to the process direction, to uniformly apply said vibratory energy to the non-rigid member, at a position at or slightly upstream in a direction opposite the process direction, from the coronode of the corona generator.

11. The device as defined in claim 10 wherein said vibratory energy producing resonator is arranged within the transfer field of the transfer corona generator and within 10 mm upstream in a direction opposite the process direction from the coronode.

12. The device as defined in claim 10 wherein said vibratory energy producing resonator includes a piezoelectric device excited by an A.C. voltage supply.

13. The device as defined in claim 12 wherein A.C. voltage supply is driven at a frequency in the range of 20 kHz to 200 kHz.

14. The device as defined in claim 13 wherein said piezoelectric device is excited to produce an output in the range of 20 kHz to 200 kHz.

15. The device as defined in claims 14 wherein said resonator is supported for line contact with the non-rigid member, said line contact arrangement oriented approximately parallel to the non-rigid member and transverse to the direction of movement of the charge retentive surface along said endless path.

16. The device as defined in claim 14 wherein the non-rigid member has an exterior charge retentive surface, upon which a developed toner image is supported, and an interior surface, on the opposite side thereof, said resonator, mechanically coupled to said interior surface of the non-rigid member.

17. The device as defined in claim 14 wherein said resonator includes a piezoelectric device excited by an A.C. voltage supply.

18. The device as defined in claim 17 wherein A.C. voltage supply is driven at a frequency in the range of 20 kHz to 200 kHz.

19. The device as defined in claim 17 wherein said piezoelectric device is excited to produce an output in the range of 20 kHz to 200 kHz.

20. In an electrophotographic device having a flexible belt-type member with a charge retentive surface moving along an endless path, means for creating a latent image on the charge retentive surface, means for developing the latent image with toner, said toner held on said charge retentive surface by electrostatic and mechanical forces, corona producing transfer means for providing non-contact transfer of the developed toner image to a copy sheet brought into contact with the charge retentive surface, said contact between said sheet and said charge retentive surface characterized by areas of intimate and non-intimate contact, and means for enhancing electrostatic transfer of said developed image to said copy sheet at said areas on non-intimate contact, said transfer enhancing means comprising:

a resonator to apply relatively high frequency vibratory energy to said charge retentive surface within a transfer field generated at said corona producing transfer means, sufficient to mechanically release said toner from said electrostatic and mechanical forces and transfer to the copy sheet at areas of non-intimate contact, and arranged with respect to said charge retentive surface and said transfer field to uniformly apply said high frequency vibratory energy to said charge retentive surface, while said developed toner image to be transferred to said sheet is within said transfer field;

said resonator supported for line contact with said charge retentive surface, said line contact oriented approximately parallel to said charge retentive surface and approximately transverse to the direction of movement thereof along said endless path;

said flexible belt-type member with a charge retentive surface having an exterior surface, upon which a developed toner image is supported, and an interior surface, on the opposite side thereof, said resonator, mechanically coupled to said interior surface of said charge retentive surface.

21. The device as defined in claim 20 wherein said resonator includes a piezoelectric device excited by an A.C. voltage supply.

22. The device as defined in claim 20 wherein A.C. voltage supply is driven at a frequency in the range of 20 kHz to 200 kHz.

23. The device as defined in claim 20 wherein said piezoelectric device is excited to produce an output in the range of 20 kHz to 200 kHz.

24. The device as defined in claim 20 wherein said means for electrostatically transferring the developed toner image to a copy sheet includes a transfer corotron and said ultrasonic energy producing means is mechanically coupled to said charge retentive surface for causing mechanical release of toner from the charge retentive surface at a position within an electrostatic transfer field created by said transfer corotron.

25. In an imaging device having a non-rigid member with a first charge retentive surface, moving in a process direction along an endless path, means for producing a toner image on the charge retentive surface, corona transfer device, having at least a first coronode driven with a relatively high voltage to a corona producing condition for providing non-contacting electrostatic transfer of the developed toner image within a transfer field to a second surface in contact with said charge retentive surface, said coronode supported within said corotron arranged generally, parallel to said charge retentive surface and transverse to the direction of movement thereof, and means for enhancing transfer of said developed image to said second surface across areas of less than optimal contact said transfer enhancing means including:

vibratory energy producing means, mechanically coupled in line contact with a second surface of said non-rigid member, applying vibratory energy enabling toner release from the charge retentive surface, at a position prior to or opposite the transfer device coronode.

26. In an imaging device having a non-rigid member with a first charge retentive surface, moving in a process direction along an endless path, means for producing a toner image on the charge retentive surface, corona transfer device, having at least a first coronode driven with a relatively high voltage to a corona producing condition for providing non-contacting electrostatic transfer of the developed toner image within a transfer field to a second surface in contact with said charge retentive surface, said coronode supported within said corotron arranged generally, parallel to said charge retentive surface and transverse to the direction of movement thereof, and means for enhancing transfer of said developed image to said second surface across areas of less than optimal contact said transfer enhancing means including:

vibratory energy producing means, mechanically coupled in line contact with a second surface of said non-rigid member, applying vibratory energy enabling toner release from the charge retentive surface, at a position directly opposite the transfer device coronode.

27. In an imaging device having a non-rigid member with a first charge retentive surface, moving in a process direction along an endless path, means for producing a toner image on the charge retentive surface, corona transfer device, having at least a first coronode driven with a relatively high voltage to a corona producing condition for providing non-contacting electrostatic transfer of the developed toner image within a transfer field to a second surface in contact with said charge retentive surface, said coronode supported within said corotron arranged generally, parallel to said charge retentive surface and transverse to the direction of movement thereof, and means for enhancing transfer of said developed image to said second surface across areas of less than optimal contact said transfer enhancing means including:

vibratory energy producing means, mechanically coupled in line contact with a second surface of said non-rigid member, applying vibratory energy enabling toner release from the charge retentive surface, at a position prior to and near the region where the transfer field is approaching its peak value.

28. In an imaging device having a non-rigid member with a first charge retentive surface, moving in a process direction along an endless path, means for producing a toner image on the charge retentive surface, corona transfer device, having at least a first coronode driven with a relatively high voltage to a corona producing condition for providing non-contacting electrostatic transfer of the developed toner image within a transfer field to a second surface in contact with said charge retentive surface, said coronode supported within said corotron arranged generally, parallel to said charge retentive surface and transverse to the direction of movement thereof, and means for enhancing transfer of said developed image to said second surface across areas of less than optimal contact said transfer enhancing means including:

vibratory energy producing means, mechanically coupled in line contact with a second surface of said non-rigid member, applying vibratory energy enabling toner release from the charge retentive surface, at a position directly opposite the region where the transfer field is approaching its peak value.