Method and device for controlling tension applied to a media web

摘要

In a web printer, tension on the moving web is controlled by monitoring the tension on the web between two rollers and selectively operating an actuator driving the second roller to restore the tension to an acceptable range. The operation of the actuator includes modulating the speed at which the second roller is driven.

主权项

1. A method of controlling a web in a printing apparatus comprising:
moving a web over a first roller and along a media path in a process direction at a web linear velocity; operating an actuator to rotate a second roller that is in contact with the web, the second roller being at a location on the media path that is offset from the first roller in the process direction; identifying at least one of a first velocity difference and a second velocity difference between a linear velocity of the second roller and at least one of a linear velocity of the first roller and the web linear velocity, respectively, the at least one of the first and second velocity differences being positive when the linear velocity of the second roller is greater than the at least one of the linear velocity of the first roller and the web linear velocity, respectively; and adjusting operation of the actuator to modulate the linear velocity of the second roller between a first linear velocity and a second linear velocity in response to the identified at least one of the first and second velocity differences being positive and above at least one of a first velocity differential threshold and a second velocity differential threshold, respectively, the first linear velocity being greater than the second linear velocity and the first and second linear velocities being greater than the at least one of the linear velocity of the first roller and the web linear velocity.