Every time I print on my
HP LJ 1020 (under
Windows 7 RTM), first printer checks does paper exist in the upper tray and only after that - in the lower.
How to force printing every time from the second one?
I've solved this once by setting the 'paper type' in the second tray to something non-default like 'pre-punched' or 'pre-printed' or 'transparent'. If you set the media type of the tray to one of these, and set the default media type also to this type this should take the paper from tray 2 (or any other tray)
I've used this trick with success in a number of HP LaserJet 4000's with 2 or 4 trays.
These specific instructions are for an HP LaserJet 8150 on Windows XP, but something similar should work for your case.
Open the Printers and Faxes window, right click on the printer, and choose "Properties." There should be a "Printing Preferences" option there. Anything you set there becomes the default for all future printing.
On my LJ 8150 there's a "Paper/Quality" tab, and under that a "Paper Source" option which defaults to "Automatically Select," but can be set to Tray 1, Tray 2, etc.
My Dell and Ricoh printers also let me select a specific tray in this "Preferences" window, so it seems likely to work on a wide variety of systems.