Konica Minolta magicolor 1690MF Reference Manual page 63

If KONICA MINOLTA mc1690MF does not appear, check that the
machine is turned on and the USB cable is connected, and then
restart the computer.
6
Check that KONICA MINOLTA magicolor 1690MF is selected in the
Print Using list.
7
Click Add.
8
Select an Optional Trays and Duplex Option to match to your printer
setup.
1-40 Printer Settings (Mac OS X 10.5/10.6)