Shipping labels printing too light on Rollo Printer

All of a sudden my shipping labels are printing very light on my Rolo Thermal Printer. It started with the new format of the Ground Advantage labels. My carrier said that the many labels are not being picked up on their scanners and they are having to manually input the tracking number. There is no problem with Click-N-Ship, Ebay or Etsy, just the Amazon labels. How long is it going to take to fix this problem?