When you use the Staple Finisher or Booklet Finisher, you need to select which one to use when copying.
Select the following menu.
If you select Auto, the printout destination is set to the finisher tray. However, this may change to another output tray depending on the paper size or the paper type.
When using the finisher tray, do not remove your printouts while copying is still in progress. The print position may be misaligned and the staple position may move from its original position.