Oce 3121 Technical & Service Manual page 689

Movement of the trays (special tray mode)
The special tray moves to the front or to the rear, prior to the commencement
of a job, to displace the output on the tray.
The output on the special tray is stacked as shown.
The tray movement motor M7 does not rotate when the output is a
Warning:
print from the host computer.
Special tray
Output (2nd job)
Rear
Output (3rd job)
Tray shift
Front
Output (1st job)
Outputs sorted on the special tray (top view)
ed.1 21 Sorter 539