New to the forum. We've had this issue with one of our 5100s for almost a year now. It gathers this gunk on the rollers, which gets on the prints and ruins them. The severity varies wildly day to day, but it's weird because our other 5100s hardly ever has this problem. We have techs in multiple times a week to clean them out, but they never seem to be able to get it to stop doing this. Anyone know what this is and is there's a way to stop it?