Feeds out a copied sheet by folding it in two. Also select the unit by which the paper is folded from [By Copy Job (Multiple Sheets)], [1 Unit], and [By Page]. When you set [By Page], specify the number of pages to be folded at one time.
This setting is displayed when the optional Finisher FS-539 SD is installed in this machine.
If Half-Fold is enabled, [Booklet] is set to [ON] automatically.