I agree with @kmf that it seems that the printer is cutting off the printing because your margins in the pattern are smaller than the margins that your printer presets. So you’ll need to set the margins in the pattern a little wider to keep the pattern within the printers printing area or set the printers margins to print to the edge of the paper. Unfortunately, I only have an A4 paper printer (a little deskjet) so I can’t test on a roll, but here is a part of a tutorial that I set up for some friends on printing the pattern in A4, if it could help you:
Printing the pattern.pdf (788.1 KB)
Other than that, perhaps you could upload your files (both .val and .vst) so that we can try a few things to try and help you.