I have a MP C2051 (internal finisher) with the following problem. When trying to staple, only the first page is stapled. The pages are not lined up before stapling. All firmware is up to date, any ideas on how to proceed would be greatly appreciated.
This sounds like the problem "Messy stacking and stapling with Internal Finisher" and it has a solution available on Tier2 website suggesting replacing two conveyer belts D4293222 and two rollers B7924041. I've replaced them myself on two occasions and that is not the most funniest thing to do but it solved the problem both times. Remember to order two of each part. These parts gets pretty worn so cleaning them does buy you some time but you will need to replace them pretty soon anyway.