Using the Embedded Web Server
Open a Web browser, and then type the printer IP address in the address field.
Click Settings > Print Settings > Quality Menu > Toner Darkness.
Adjust the setting, 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 .
Here are steps on how to adjust the max send/receive speed in fax environments with poor line quality or noisy phone lines.