If a printing image shows the white line or scratches on its surface, we primarily assume that dusts or particles may be stuck on the roller of printer-head.For solving this problem, we recommend to use the cleaning paper which supplied together with the thermal video printer when you bought the printer.If you have no this cleaning paper and need to clean the printer-head promptly, you're kindly advised to follow the below steps. 1. Open the printer front 2. Insert the thermal paper in opposite side into the printer 3. Close the printer front and print a image 3-4 times in general 4. Open the print front and take the paper roll out of the printer 5. Insert the thermal paper in normal side for printing 6. Close the printer front and print a image 7. Most of dusts and particles are removed on printer-head now.