I was having the same problem. The paper size method didn't work for me, but while I was looking at that I noticed that the "Scale" was set to 46% instead of Default. I changed it to "Default" and it fixed the problem.
This fixed my problem - all of a sudden my checks were printing tiny fonts, and the placement was completely off.
My issue was also "scale", but I had it set at Print To Size/Page... I changed it back to Default, and that fixed it.