No, that isn't the problem here.

Whether or not duplexing is selected for Tray 2, the printer uses exactly the same rollers, from pick roller through feed/registration roller through transfer roller, through the four drums and the fuser, and finally the output tray.

With duplexing selected, the first page prints duplexed very reliably; then the pick roller grabs the next sheet of paper out of the tray, takes it to the feed/registration roller which apparently doesn't activate, because the paper drops onto the table under the printer, where it can be picked up and re-used. Note that the failure occurs long before the paper ever gets to the duplexer, in fact long before the paper goes anywhere.

With duplexing NOT selected, the pick roller grabs the paper out of the tray, takes it to the feed/registration roller which happily takes it and feeds it through the rest of the process with virtually 100% reliability. According to the status page, there have only been four actual paper jams in all the time I have had the printer. That's 99.97% reliability.

A 100 page print run will operate flawlessly with duplexing NOT selected. A 2-page print run will fail at least 90% of the time when duplexing IS selected, yet the failure has nothing to do with the actual physical duplexing process. I think it's a timing thing. While duplexing, there has to be a delay before the second and subsequent pages are picked up to allow for the extra time needed for the first page to complete its pass through the duplexer. Either the pick roller is picking the next page up too soon and the feed/registration roller isn't ready for it, or else the pick roller is right on time and the feed/registration roller doesn't activate.

Since Tray 1 has its own pick roller but uses the same feed/registration roller as Tray 2, I suspect that the problem is early pick on Tray 2 because Tray 1 will duplex all day long without any problems.

tanstaafl.