System for applying vacuum force on web

Patent metadata

Field	Value
Publication number	US-9233559-B2
Application number	US-201414291156-A
Country	US
Kind code	B2
Filing date	May 30, 2014
Priority date	May 30, 2014
Publication date	Jan 12, 2016
Grant date	Jan 12, 2016

Abstract

Apparatus for causing a vacuum force to be applied across a width of a print medium as it moves through a printing system and for determining whether the edge seals are positioned correctly is disclosed. A vacuum chamber is connected to a vacuum source which provides vacuum to the vacuum chamber. Spaced sealing rollers and the edge seals define an opening in the vacuum chamber, wherein the print medium passes over the opening and is guided by the sealing rollers. A sensor measures a vacuum level in the vacuum chamber. A controller stores a plurality of response curves for different known print media, produces first and second signals indicative of an activation level of the vacuum source and the vacuum level in the vacuum chamber, and compares the first and second signal to appropriate response curves to produce an error signal indicating whether the edge seals are correctly positioned.

First claim

The invention claimed is:

1. Apparatus for causing a vacuum force to be applied at a target vacuum level across a width of a web of movable print medium as it moves through a printing system and for determining whether positions of adjustable edge seals of the apparatus do not correspond to edge positions of the movable print medium, comprising:
a vacuum chamber connected to a vacuum source, wherein the vacuum source provides vacuum to the vacuum chamber;
spaced sealing rollers, disposed in relation to the vacuum chamber, that rotate as the print medium moves over each sealing roller, wherein the spaced sealing rollers define an opening in the vacuum chamber, and wherein the movable print medium passes over the opening and is guided by the sealing rollers;
the adjustable edge seals disposed between the spaced sealing rollers at a first position;
a sensor for measuring a vacuum level in the vacuum chamber; and
a controller having controller accessible memory for storing a plurality of response curves for different known print media having different widths, materials, or thickness, responsive to the vacuum source and the sensor, for producing a first signal indicative of an activation level of the vacuum source and a second signal indicative of the vacuum level in the vacuum chamber, and for comparing the first and second signal to appropriate response curves corresponding to the movable print medium to produce an error signal indicating whether the first position of the pair of edge seals does not correspond to the width of the movable print medium.

2. The apparatus according to claim 1 , further including means for adjusting the position of at least one of the edge seals to at least one new position in response to the error signal.

3. The apparatus according to claim 2 , wherein the new position of the edge seals corresponds to a change in an operating region of the response curves.

4. The apparatus according to claim 2 , wherein the new position of the edge seals corresponds to edges of the movable print medium so that an appropriate vacuum force is applied across the width of the movable print medium.

5. The apparatus according to claim 2 , wherein the means for adjusting the positions of the edge seals includes separate means for adjusting the position of each of the edge seals independently of the position of the other edge seal.

6. The apparatus according to claim 2 , wherein the means for adjusting the positions of the edge seals comprises means to adjust the position of a first edge seal and a second edge seal concurrently such that a midpoint between the first edge seal and the second edge seal is substantially fixed independent of a spacing between the first edge seal and the second edge seal and corresponds to a midpoint of the width of the movable print medium.

7. The apparatus according to claim 1 , wherein the sealing rollers are disposed at two positions in an intrack direction and extending parallel to a crosstrack direction relative to the movement of the movable print medium.

8. The apparatus according to claim 1 , wherein the edge seals are disposed at two positions in a crosstrack direction and extending parallel to an intrack direction relative to the movement of the movable print medium.

9. The apparatus according to claim 1 , wherein the sensor is a pressure sensor used to measure the vacuum level in the vacuum chamber.

10. The apparatus according to claim 9 , further including means responsive to the controller for adjusting the activation level of the vacuum source to adjust the vacuum level in the vacuum chamber until the pressure sensor indicates that the vacuum level in the vacuum chamber corresponds to a target vacuum level for the movable print medium while monitoring the first signal.

11. The apparatus according to claim 1 , further including means responsive to the controller for adjusting the activation level of the vacuum source until the first signal corresponds to a target activation level of the vacuum source for the movable print medium while monitoring the second signal.

12. The apparatus according to claim 1 , wherein the vacuum source is a blower and the first signal is indicative of the speed of the blower.

13. The apparatus according to claim 1 , wherein the activation level of the vacuum source is measured using the drive voltage level to the vacuum source, the current flow to the vacuum source, the phase difference between the vacuum source drive voltage and the current, the duty cycle of a pulse width modulated vacuum source, the rotational rate of the vacuum source, or the position of a valve that alters the flow of air from the vacuum chamber to the vacuum source.

14. The apparatus according to claim 1 , wherein the sensor is a vacuum gauge fluidically coupled to the vacuum chamber or to a vacuum duct that connects the vacuum chamber to the vacuum source.

15. The apparatus according to claim 1 , wherein the sensor is a strain gauge attached to a wall of the vacuum chamber to measure the deformation of the vacuum chamber wall produced by the vacuum, a force gauge measuring the force applied to one or more guiding surfaces by the movable print medium as it is pulled into contact with the guiding surfaces by the vacuum, a force gauge measuring the force applied by the vacuum to the edge seals, or a flow gauge measuring the flow rate of the air through a vacuum duct between the vacuum chamber and the vacuum source.

16. The apparatus according to claim 1 , wherein the vacuum source is a blower, a pump, or a venturi-type vacuum source.

17. The apparatus according to claim 1 , further including a clearance gap between the sealing rollers and a wall of the vacuum chamber, the clearance gap extending around a portion of the sealing rollers.

18. The apparatus according to claim 17 , wherein the clearance gap extends around at least an eighth of the circumference of the sealing roller.

19. The apparatus according to claim 1 , wherein each of the adjustable edge seals includes a vacuum opening.

20. The apparatus according to claim 19 , wherein the plurality of response curves permit detection of partially uncovered vacuum openings.

Assignees

• Eastman Kodak Co

Inventors

• Young Timothy John
• Kulzer Gregory R

Classifications

• B41J11/0085 Primary

  Using suction for maintaining printing material flat (on rotatable drums B41J13/226) · CPC title