Open a Web browser, and then type the printer IP address in the address field.
> Print Settings
> Quality Menu
> Toner Darkness.
Adjust the toner darkness, and then click Submit.
Using the printer control panel
From the home screen, navigate to:
> Settings > Print Settings > Quality Menu > Toner Darkness
Adjust the setting, and then touch Submit.
Fine Lines in DBCS Fonts (Specifically Chinese Characters) Are Not Printed Clearly
How to Properly Adjust the Fax Tone Volume to Low or Off