I've had this problem before. All the usual tips and hacks (cleaning/inks/driver) don't work - why it is that my ip8750 typically won't print to A3 and simply spits out the paper - blank.
I seem to recall when last this occurred it had more to do with the program and image file type than the printer itself. Could anyone jog my memory. Like I say, this only occurs with A3 paper. A4 is unaffected.