Booklet printing

I'm printing on a Canon Pixma MG5220.
I set up the printer for booklet printing on 81/2x11 paper. The print came out way too small (smaller than the Arial 12 of the document) and there are huge margins. WHY???!!!!!

Check the printer settings, it might be set to reduce what you print or it could be the document file itself that you're trying to print.

Try looking through printer reviews or online manuals to see if any of them can give you some insight. Most likely though it's a configuration problem, so focus on that, too.