As a follow up for others who may encounter this: I spoke with Bailey and they told me to first check the set screw on the top roller at the back (inside the plastic housing.). It sometimes slips off the flat surface of the roller rod so the roller isn't grabbing well. If this doesn't work and it turns out that the surface of the rollers has become worn smooth (which he says usually takes a long time - many years) they recommend removing the rollers, masking off the ends and spraying them uniformly with a light coat 3M Super 77 (spray mount adhesive). Allow it to cure for 24 hours before reinstalling. They have a machine they have been using like this for 5 years and it's still going strong. The rollers can be recoated if necessary.