Toshiba MULTIFUNCTIONAL DIGITAL COLOR SYSTEMS 6520C - Manual (Page 102)

4 EDITING FUNCTIONS
100 Image Shift
2 Press [BOOK].
3 Adjust the width of the binding margin.
1) Press either [ 2 mm] (0.08") or [ 30 mm] (1.18").
2) Press [OK].
4 Press [OK].
Select the “Book-type original -> 2-sided copy” mode as well.
P.87 “Making a 2-sided copy from a book-type original”