System for generating vacuum response curves

1. A system for generating a response curve for adjusting the positions of a pair of adjustable edge seals to the width of a web of movable print medium in a printing system, 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, 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;

means for adjusting the position of at least one of the adjustable edge seals to at least one new position; and

a controller for producing at least one of 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 for the first position, for producing at least one of a first signal indicative of the activation level of the vacuum source and a second signal indicative of the vacuum level in the vacuum chamber for the at least one new position, and for producing a response curve using the first or second signals produced at the first and at least one new positions.

2. The system according to claim 1 , further including controller accessible memory for storing the response curve.

3. The system according to claim 1 , wherein the at least one new position of the pair of edge seals corresponds to an operating range different from that of the first position.

4. The system according to claim 1 , 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.

5. The system according to claim 1 , 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.

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

7. The system 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.

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

9. The system according to claim 8 , 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.

10. The system 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.

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

12. The system 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.

13. The system 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.

14. The system 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.

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

16. The system 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.

17. The system according to claim 16 , wherein the clearance gap extends around at least an eighth of the circumference of the sealing roller.