Brother MFC-8640D - Manual (Page 40)

2 - 15 PRINTER DRIVER SETTINGS
Print Date & Time
When enabled the Print Date and Time feature will automatically
print the date and time from your computers system clock on your
document.
Click the Setting button to change the Date and Time Format. You
can change the Font by clicking the Font button or the Position. To
include a background with the Date and Time select Opaque. When
Opaque is selected you can set the Darkness of the Date and Time
background by changing the percentage.
The Date and Time indicated in the selection box represents the
format that will be printed. The actual Date and Time printed on
your document is automatically retrieved from the settings of
your computer.