Media hold down system

• US 20050190250A1
• Filed: 02/26/2004
• Published: 09/01/2005
• Est. Priority Date: 02/26/2004
• Status: Active Grant

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Pickup, Ray L., Howarth, Steven J.
• Granted Patent: US 6,997,549 B2
• Time in Patent Office: Days
• US Class Current: 347/104
• CPC Class Codes: B41J 11/007 Conveyor belts or like feeding devices
• CPC Class Codes: B41J 11/0085 Using suction for maintaining printing material flat on rotatable drums B41J13/226
• CPC Class Codes: B41J 11/04 Roller platens

Abstract

A media hold down system includes electrodes configured to create an electric field at a surface and a vacuum source configured to create a vacuum at the surface.

Claims

1. A media hold down system comprising:

electrodes configured to create an electric field at a surface; and

a vacuum source configured to create a vacuum at the surface.

2. The system of claim 1 including a first current source electrically coupled to spaced portions of one of the electrodes.

3. The system of claim 2 including a second current source electrically coupled to spaced portions of the other of the electrodes.

4. The system of claim 1, including a first opening between a first portion and a second portion of one of the electrodes, wherein the vacuum source is configured to create a vacuum through the first opening.

5. The system of claim 4 including a second opening along the surface, wherein the vacuum source is configured to create a vacuum through the second opening.

6. The system of claim 5, wherein the second opening is between a third portion and a fourth portion of the other of the electrodes.

7. The system of claim 5, wherein the second opening is between the first portion and the second portion of said one of the electrodes.

8. The system of claim 1, wherein the first electrode has a transverse width W and wherein consecutive electrodes are transversely spaced from each other by a distance of about one-third W.

9. The system of claim 1, wherein the surface is configured to be moved while the media is positioned against the surface.

10. The system of claim 1, wherein the assembly is configured to create an electrostatic hold down force between the surface and the medium, wherein the vacuum source creates a vacuum hold down force and wherein the electrostatic hold down force is greater than the vacuum hold down force.

11. The system of claim 1, wherein one of the electrodes has a first portion opposite a second portion, wherein the first portion is transversely spaced from the second portion by a distance D, wherein the second opening is between the first portion and the second portion and has a transverse dimension substantially equal to the distance D.

12. The system of claim 11, wherein the transverse dimension D is less than about 10 mils.

13. The system of claim 1 including a heating element at least partially disposed within the surface.

14. A media hold down system comprising:

a surface configured to be positioned against a medium;

an electrostatic hold down element; and

a vacuum source configured to create a vacuum at the surface.

15. The system of claim 14 including a heating element proximate to surface.

16. The system of claim 15, wherein the heating element and the electrostatic hold down element include a common electrode along the surface.

17. The system of claim 15, wherein the electrostatic hold down element includes:

a voltage source;

a first electrode proximate the surface, electrically coupled to the voltage source and configured to have a positive charge; and

a second electrode proximate the surface, electrically coupled to the voltage source and configured to have a negative charge.

18. The system of claim 17, wherein the heating element includes a first current source electrically coupled to spaced portions of one of the first electrode and the second electrode.

19. The system of claim 18 including a second current source electrically coupled to spaced portions of the other of the first electrode and the second electrode.

20. The system of claim 15, wherein the heating element includes:

an electrode proximate the surface; and

a current source electrically coupled to spaced portions of the electrode.

21. The system of claim 17, including a first opening between a first portion and a second portion of one of the first electrode and the second electrode, wherein the vacuum source is configured to create a vacuum through the first opening.

22. The system of claim 17 including a second opening along the surface.

23. The system of claim 22, wherein the second opening is between a third portion and a fourth portion of the other of the first electrode and the second electrode.

24. The system of claim 22, wherein the second opening is between the first portion and the second portion of said one of the first electrode and the second electrode.

25. The system of claim 17, wherein one of the first electrode and the second electrode has a transverse width W and wherein the first electrode and the second electrode are transversely spaced from each other by a distance about one-third W.

26. The system of claim 14, wherein the surface is configured to be moved while the medium is held against the surface by the electrostatic hold down element.

27. The system of claim 14, wherein the electrostatic hold down element is configured to create an electrostatic hold down force between the surface and the medium, wherein the vacuum source is configured to create a vacuum hold down force and wherein the electrostatic hold down force is greater than the vacuum hold down force.

28. The system of claim 17, wherein the first electrode has a first portion opposite a second portion, wherein the first portion is transversely spaced from the second portion by a distance D and wherein the second opening is between the first portion and the second portion and has a transverse dimension substantially equal to the distance D.

29. The system of claim 28, wherein the transverse dimension is less than about 10 mils.

30. A fluid ejection system comprising:

a fluid ejection mechanism configured to eject fluid onto a medium;

a surface configured to be positioned against the medium;

an electrostatic hold down element; and

a vacuum source configured to create a vacuum between the surface and the medium.

31. The system of claim 30 including a heating element proximate the surface.

32. The system of claim 31, wherein the heating element and the electrostatic hold down element include a common electrode along the surface.

33. The system of claim 30, wherein the fluid ejection mechanism is configured to eject ink onto the medium.

34. The system of claim 30, wherein the surface is configured to be moved while the medium is held against the surface.

35. The system of claim 34, wherein the surface is provided by a belt.

36. The system of claim 34, wherein the surface substantially encircles a drum.

37. A media hold down system comprising:

means for electrostatically holding a medium along a surface; and

means for removing air between the medium and the surface as the medium is held down.

38. The system of claim 37 including means for heating the medium as the medium is held down.

39. The system of claim 38, wherein the means for heating is at least partially received within the surface.

40. A method for handling media, the method comprising:

electrostatically holding a medium along a surface; and

removing air between the medium and the surface as the medium is held down.

41. The method of claim 40 including the heating the medium as the medium is held down.

42. The method of claim 40 including moving the surface as the medium is held along the surface.