HP LaserJet 9000 Printer series - Manual (Page 11)

ENWW Configuring control panel settings 11
Default stapler actions for bin 1 (stacker bin)
No Staple If the default action is set to NO STAPLE , the job is not stapled.
Corner Staple If the default action is set to ONE STAPLE , the staple is placed in
the top left corner of the document. If you are printing in
landscape format, the staple location is automatically adjusted for
placement in the top left corner of the landscape layout.
Two Staples If the default action is set to TWO STAPLES , two staples are used
with one job or with mopies. Both staples are placed parallel to
the edge closest to the printer (the trailing edge).