Brother MFC-3100C Owner's Manual page 64

Special Copy Options (Not available with Colour Copy)
You can save paper by copying two pages onto one page.
1
Insert the documents face down in the Automatic Document Feeder.
2
Press Options and
3
Press or
4
Press Mono Copy—OR—Press
2 in 1
Special Copy Option is not available with reduced, enlarged or colour copies.
53
Chapter 11
or to select SPECIAL, and then press Menu/Set.
to select 2IN1, and press Menu/Set.
or
1
2
additional settings.
1 2