First off you didn't mention your OS,XP, VISTA, Win 7. If the unit came with CD/driver disk , assume you loaded. Depending upon the OS, it sounds as if it could be a compatibility issue (software). It may be that you need to update the drivers (if available) from Canon's website. Having seen this many times with many and most manufacturers, it may be resolvable. There are occasions, however, when the unit to OS software upgrade is not available. Best of luck.
Ok to be honest with you i have very little faith that I will be able to solve this problem through CNET Forums as it's very technical however I will put it out there, maybe someone will suggest something to look for, look I really don't know.
Simple story.
I buy a printer (second hand, thinking I'm clever). It's a MPC600F. Now this printer is apparently old, I mean relatively old. So I install the drivers and all that stuff plug in the USB cord and I'm away.
Here's the thing though. When I print stuff from the computer (Microsoft Word 2007) it prints blank pages. Now this would be annoying but there's a twist.
At first I thought there was something wrong with the print heads but when I scan something (which obviously does not require it to interact with the computer) then it prints normally. So you can't say it's because there's anything wrong with the printheads.
There's another twist though. When I print from a Web Browser (Google Chrome) it prints on the page... it's still really wonky and missing large chunks of text but the point is that I can see hope.
So, just imagine you're in my position? What do you check for?
Regards

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic