My MG8220 was jamming if fed from the cassette, or the rear tray. I tried everything! But then decided to REALLY clean EVERYTHING in the paper path. The rear rollers, the rollers behind the ink cartridges. which I think was the culprit. I took a q-Tip and simple green cleaner and scrubbed and scrubbed those rollers. I discovered they were in fact not black! They are grey! There is also a metal bar below the rollers that has a somewhat gritty surface. I am guessing to aid in paper moving through. I cleaned it also. After I was satisfied it was SPOTLESS, I fired it up and printed perfectly from cassette or rear tray! YEAH!