M126/M127/M128  6-78  SM 
Print quality problems 
 
Problem  Cause / action 
Light or blurred 
characters. 
 
Light print 
See “Light print” in “Troubleshooting”. 
The toner cartridge may be getting low on toner: 
  Remove the toner cartridge and print cartridge assembly. 
  Shake it from side to side to redistribute the toner. 
  Reinstall it, and recheck for condition. 
  Make sure to use the recommended print media (see media 
types and sizes in the User’s Guide). 
  Use MarkVision™ Professional to define the custom type 
setting for media type, media texture, or media weight. 
  The toner cartridge or PC Kit may be defective. Replace the 
PC Kit first, and recheck. 
Blurred characters 
Blurred images, including characters, are usually caused by a 
defective printhead. 
Vertical white lines 
See “Vertical streaks” below. 
Vertical white lines may be caused by the laser beam, which may 
be partially blocked. With the machine off, clear the path or clean 
the lens. The toner cartridge or fuser may be defective. Try a 
different toner cartridge. Inspect the fuser at its entry for debris. 
Toner smudges 
appear on the front 
or back of the page. 
  Make sure the media is straight and unwrinkled. 
  Replace the PC Kit, and recheck before replacing the toner 
cartridge. See “Toner on back of page” in “Troubleshooting” 
for more information.