canon i560 leaves black marks

[eddy]

When I print a page from my canon it is leaving small black marks on the very end of page sometimes and even some on the side. I tried a new cartridge but the same thing happens. How do you clean the rollers. I see there is some white nylon rollers and small black rubber rollers when you lift the top. How do you turn them to clean and are there any more at the back or underneath. Also there is the long spongy material where the print head rolls against, what about that. Please help me if you can as I need to print out wedding invitations....Ed

eddy@cablerocket.com[/FONT]