You can copy two pages of an original on both sides of the paper. You can also copy a 2-sided original on both sides of the paper, or on two separate pages.
NOTE
<2-Sided> may not be available with some sizes and types of paper. Paper Handling
<Other Settings> <2-Sided> Select the type of 2-sided copying <Apply>
Types of 2-sided copying
The illustration below shows the types of 2-sided copying.
<1-Sided->2-Sided>
<2-Sided->2-Sided>
<2-Sided->1-Sided>
<Orig./Fin. Type>
Specify the original orientation, opening type, and finishing type.
<2-Sided> 
Types of 2-sided copying
<Orig./Fin. Type>