Lexmark T620 Service Manual - Page 140

4069-5XX/7XX Print Quality - Random Marks Service Tip: The primary cause of random marks is due to loose material moving around inside the printer and attaching to the photoconductor, charge roll or transfer roll. Symptom 1 Random Marks Action Check the print cartridge for any signs of loose or foreign material that might be on the photoconductor. Check the transfer roll and charge roll for any pieces of material that are stuck to the rolls. Print Quality - Blurred or Fuzzy Print Blurred of fuzzy print is usually caused by a problem in the main drive gearbox assembly, alignment assembly, any feed roller or in the transfer roll bearings or transfer roll. Check the gearbox assembly for correct operation. Check the transfer roll for binds or a contaminated shaft or bearings. Blurred print can also be caused by incorrect feeding from one of the input paper sources, paper trays, duplex option or envelope feeder. Check the high voltage contacts to ensure they are not bent, corroded or damaged. Replace as necessary. 2-112 Service Manual