Brother makes many printing devices. They operate best when maintained properly. If your print quality has declined, your printer heads may need to be cleaned. Each device comes with owners documents detailing how to clean your printer heads for the longevity of your equipment. You can also refer to these specific directions to clean a Brother Fax machine's printer heads.
Disconnect the power cord and the phone line. According the directions for your fax machine this will help to ensure your safety.
Locate the lever on the right side of the top cover. Pull this lever to open the top.
Remove the fax/print cartridge by pulling on its attached release lever. You will now see the fax/printer head.
Clean the fax/printer head by wiping it with a lint free cloth moistened lightly with rubbing alcohol.
Replace the fax/print cartridge when the fax/printer head is dry. Replace the cartridge by inserting one end and tilting the other end into the fax/printer until it clicks.
Close the top cover of the fax/printer by pressing down on both sides until the top clicks. Your fax/printer should be operational.
There are many other Brother printing devices. You can find out how to clean the printer heads on these other devices by referring to your owner's documents or checking online.
The parts of your fax machine will be hot after recent operations so be careful to avoid burns.