Media guiding system using bernoulli force roller

1. A media-guiding system for guiding a media travelling from upstream to downstream along a transport path in an in-track direction, the media having a first side and an opposing second side, comprising:

a media-guiding roller having a roller axis and an exterior surface having one or more grooves formed around the exterior surface, wherein the media travels along the transport path past the media-guiding roller with the first side of the media facing the exterior surface of the media-guiding roller;

an air source for providing an air flow into one or more of the grooves, the air flow being directed between the first side of the media and the exterior surface of the media-guiding roller thereby producing a Bernoulli force to draw the media toward the exterior surface of the media-guiding roller and providing an increased traction between the media and the media-guiding roller; and

a roller control mechanism for adjusting an orientation of the roller axis relative to the in-track direction of the media, thereby providing a steering force to steer the media in a cross-track direction.

2. The media-guiding system of claim 1 further including a control system for selectively activating the air source, wherein when the air source is activated the Bernoulli force draws the media toward the exterior surface of the media-guiding roller providing a higher traction between the media and the media-guiding roller, and when the air source is not activated no Bernoulli force is produced providing a lower traction between the media and the media-guiding roller.

3. The media-guiding system of claim 2 wherein the roller axis is oriented in a non-orthogonal direction relative to the in-track direction such that when the air source is activated the media is steered in a cross-track direction as it passes the media-guiding roller.

4. The media-guiding system of claim 3 further including a media edge detector that detects a position of an edge of the media, and wherein the control system controls the air source in response to a signal from the media edge detector.

5. The media-guiding system of claim 1 further including an edge stop positioned along one edge of the media, wherein the roller axis is oriented to provide a steering force that pushes the media against the edge stop thereby maintaining a substantially constant cross-track position of the media.

6. The media-guiding system of claim 1 further including a media edge detector that detects a position of an edge of the media, and wherein the roller control mechanism adjusts the orientation of the roller axis in response to a signal from the media edge detector.

7. The media-guiding system of claim 1 wherein the media guiding roller is mounted to a frame, and wherein the roller control mechanism includes an actuator or a stepper motor that adjusts the orientation of the roller axis by rotating the frame around a rotation axis.

8. The media-guiding system of claim 1 wherein the media contacts the media-guiding roller for a wrap angle of less than 5 degrees as it passes the media-guiding roller.

9. A media-guiding system for guiding a media travelling from upstream to downstream along a transport path in an in-track direction, the media having a first side and an opposing second side, comprising:

a media-guiding roller having a roller axis and an exterior surface having one or more grooves formed around the exterior surface, wherein the media travels along the transport path past the media-guiding roller with the first side of the media facing the exterior surface of the media-guiding roller;

an air source for providing an air flow into one or more of the grooves, the air flow being directed between the first side of the media and the exterior surface of the media-guiding roller thereby producing a Bernoulli force to draw the media toward the exterior surface of the media-guiding roller and providing an increased traction between the media and the media-guiding roller; and

an air shoe in proximity to the media-guiding roller, wherein the media passes over the air shoe on a cushion of air, and wherein the media-guiding roller stabilizes a cross-track position of the media as the media passes over the air shoe.

10. The media-guiding system of claim 1 wherein the media is a web of media.

11. The media-guiding system of claim 1 wherein the media is a cut sheet of media.

12. The media-guiding system of claim 1 wherein the media-guiding roller spans a cross-track width of the media.

13. The media-guiding system of claim 1 wherein the media-guiding roller has a width in the direction of the roller axis which is less than 20% of a cross-track width of the web of media.

14. The media-guiding system of claim 1 further including a drive mechanism that rotates the media-guiding roller around its roller axis.

15. The media-guiding system of claim 1 wherein the media-guiding roller has a plurality of grooves, and wherein a separate air source is used to provide the air flow into each of the grooves.

16. The media-guiding system of claim 1 wherein the media-guiding roller has a plurality of grooves, and wherein the air source includes a plenum having openings corresponding to each of the grooves to direct the air flow into the corresponding grooves.

17. The media-guiding system of claim 1 wherein the air flow is directed into the one or more of the grooves in a direction substantially parallel to the grooves.

18. The media-guiding system of claim 1 wherein the exterior surface of the media-guiding roller is concave.

19. The media-guiding system of claim 9 wherein the roller axis is substantially perpendicular to the in-track direction.

20. A media-guiding system for guiding a media travelling from upstream to downstream along a transport path in an in-track direction, the media having a first side and an opposing second side, comprising:

a first media-guiding roller having a first roller axis and an exterior surface having one or more grooves formed around the exterior surface, wherein the first media-guiding roller has a width in the direction of the first roller axis which is less than 20% of a cross-track width of the web of media, and wherein the media travels along the transport path past the first media-guiding roller with the first side of the media facing the exterior surface of the first media-guiding roller;

a first air source for providing an air flow into one or more of the grooves formed around the exterior surface of the first media-guiding roller, the air flow being directed between the first side of the media and the exterior surface of the first media-guiding roller thereby producing a Bernoulli force to draw the media toward the exterior surface of the first media-guiding roller and providing an increased traction between the media and the first media-guiding roller;

a second media-guiding roller having a second roller axis and an exterior surface having one or more grooves formed around the exterior surface, wherein the second media-guiding roller has a width in the direction of the second roller axis which is less than 20% of the cross-track width of the web of media; and

a second air source for providing an air flow into one or more of the grooves formed around the exterior surface of the second media-guiding roller, the air flow being directed between the first side of the media and the exterior surface of the second media-guiding roller thereby producing a Bernoulli force to draw the media toward the exterior surface of the second media-guiding roller and providing an increased traction between the media and the second media-guiding roller.

21. The media-guiding system of claim 20 wherein the first media-guiding roller is located in proximity to a first edge of the media and the second media-guiding roller is located in proximity to an opposite second edge of the media.

22. The media-guiding system of claim 21 the first roller axis is not parallel to the second roller axis to provide a stretching force or a compressing force to the media in the cross-track direction.