Noob having problems with Canon IPF6300

Hi all , I am a relative newcomer to printing and come from a film and video background. However given the amount we were spending on promo printing and due to a very lucky break I bought a Canon IPF 6300. I am printing tests and exploring different paper types and sizes. All was going well when using the paper roll but since doing tests on single sheets I can't seem to print without getting unbalanced borders or zoomed in prints that mean only a fraction of the picture is printed over the entire page. I have gone over all the settings in the proprietry print plugin and cannot work out why this is happening. The settings I have should be fine yet I notice I cannot move the blue canvas border lines to incorporate all of the grey background window. I don't mean the resize border for the picture itself but the area below it.
Has anyone come across this before? Can anyone offer a solution or at least an idea as to what I am doing wrong.
Thank you