After years of fighting with Rolands take up reel system on our XR640, we finally invented a solution that works. We've had everyone from Roland try to figure it out. We've adjusted the silver dancer bar a million times, we've tightened, re-tightened, adjusted, etc. - the take up simply doesn't work the way it's designed, and we figured out why.
We programmed the distance sensor on the floor (which is put higher for more accuracy on the plastic roll ends) to detect the vinyl, which then turns the servo, which pushes the manual feed button on the take up reel once. The silver tension bar works to keep weight on the roll and on what's being taken up, while keeping the material from getting sideways and getting the "floppy left side and tight right side" Roland tension issue, which means it keeps the material straight and away from the print heads above. This is on a completely unadjusted Roland take up reel. If this system was taken away, we would only make it around 15 feet before head crashing. We worked months on this to try to find a solution and this one works perfectly on 2 Rolands so far.
[video=youtube;NwuNuQuKosE]https://www.youtube.com/watch?v=NwuNuQuKosE[/video]
We programmed the distance sensor on the floor (which is put higher for more accuracy on the plastic roll ends) to detect the vinyl, which then turns the servo, which pushes the manual feed button on the take up reel once. The silver tension bar works to keep weight on the roll and on what's being taken up, while keeping the material from getting sideways and getting the "floppy left side and tight right side" Roland tension issue, which means it keeps the material straight and away from the print heads above. This is on a completely unadjusted Roland take up reel. If this system was taken away, we would only make it around 15 feet before head crashing. We worked months on this to try to find a solution and this one works perfectly on 2 Rolands so far.
[video=youtube;NwuNuQuKosE]https://www.youtube.com/watch?v=NwuNuQuKosE[/video]