The printer successfully prints both sides from the computer ( print command ), but only seems to print one side using the ADF and having the Duplex button lit up...
The user manual sez ( pg 6.4 ):
Copying on both sides of paper
By using the Duplex button on your machine, you can set the machine to
image on both sides of paper.
1 Press Duplex.
2 Press the Scroll buttons until the binding option you want appears.
• Off: Prints in Normal mode.
• 1->2Side Short: Prints pages to be read by flipping like a note
• 1->2Side Long: Prints pages to be read like a book.
3 Press Enter to save your selection.
If the mode is enabled, the Duplex button is backlit.
4 Start copying a document.
It *only* prints in Normal mode, no matter what the Duplex button is saying....
How to get it to Duplex copy?