Brother MFC-8640D - Manual (Page 87)

4 - 15 USING CONTROLCENTER2.0
Scan to File:
In the General tab
You can enter up to 30 characters in the Name for Custom field.
This name will appear as the button name.
Select the type of scan from the Scan Action field.
In the Settings tab
Select the file format from the File Type pull down list. You can either
send the file to the default folder which is shown currently in the
Destination Folder box or select your preferred folder by using
button.
You can also select Resolution, Scan Type, Document Size,
Brightness and Contrast settings.