Enhance the print quality.
From the home screen, touch Settings > Print > Quality.
Adjust the settings.
Is the fax print quality satisfactory?
The problem is solved.
Go to step 2.
Decrease the incoming fax transmission speed.
From the home screen, touch Settings > Fax > Analog Fax Setup > Fax Receive Settings > Admin Controls > Max Speed.
Select a lower transmission speed.
Go to step 3.
Replace the toner cartridge.
For more information, see the instruction sheet that came with the supply.
Contact customer support.