If lines go diagonally across the printing…
The is most likely a problem with the ribbon. Check the following:
If the lines are perfectly straight, but they go in and out the print head is probably dirty. Be sure the printer is turned off and unplugged. Then clean the print with the cleaning swabs provided with your DuraLabel PRO supplies, or with rubbing alcohol and a cotton swab.
If the lines are in the shape of a crevice (like a slash in the print) the print head density is probably set too high. Try lowering the darkness settings in the printer properties.
If there are random voids on the edges of the label, there is most likely a buildup of adhesive in the guides. The printer, including the guides, should be cleaned. what happens is that randomly, as the tape moves through the guides, a piece of adhesive will stick to the vinyl. when that happens the ink from the ribbon does not transfer properly with the result being a small void in the printing. this typically only happens on the very edges of the vinyl.