I'm posting this Tech Tip so that I won't have to wrestle with this issue the next time it rears its ugly head; and, trust me, it will.
Here's where the ridiculousness of all this begins. In order to figure all this out, I had to put a letter size piece of paper in the manual feed tray to see how the document would print.
In the past, I've had to "fool" the printer into thinking it was printing on a "Letter" sized document, but I'd put the content, sort of, in the middle of the page so, when the card went through, it would print out correctly. If that sounds too complicated, don't worry about.
This is what the printer industry has foisted on all of us and we, blithely, sit by while they dangle us like puppets on a string. But I for one say, NO - I'll all for saving the Rainforest. NO MORE PRINTING. I mean, seriously, who needs to clutter up their lives with paper. We should be ashamed that we're still stuck in the 1990's and chained to outdated technology!