Air Print issue on WF-7840 - Paper Tray Priority Switch

[rallen]

I recently had an issue trying to use AirPrint from an Apple device to a WF-7840. To make a long story short, it was a "Paper Tray Priority" switch turned on that would naturally generate an Out of Paper Error when trying to AirPrint form an iPad or iPhone to this printer. The "Paper Tray" is the manually fed tray on the back side of the printer used for card stock, etc., the others on the front are called cassettes. Turning off the switch allowed the selection of "Cassette 1" to be used for the print job. There is no reference to the Priority Switch in the original manual for the printer, it must have come from a firmware update that installed it and turned it on. I contacted both Epson support and Apple support, we went through network status connections, paper type and loading, powered down and powered up. I spent 45 minutes with each on the phone. There were no wireless connection issues. I tried changing settings on my own while on the phone with Apple. The Tech from Apple and myself, laughed about it when it started working. Hope this eliminates some head scratching for users in the future.