Didn't we have a similar conversation once before?
We had a proper 'commercial office quality' Lexmark in my old job, because we'd print hundreds of pages a day. It always jammed, never pulled from the right tray, smeared the text. In the end the IT department got so fed up with having to constantly come and repair it that they just picked it up off the desk and deliberately dropped it on the floor so it broke and said, 'Oh, that's broken, that is. Best order you a new HP printer'.
Don't suppose you remember what model it was did you?
Tray problems - incorrect settings.
Jamming - fuck knows, could be any number of things. They normally display an error code that tells us guys exactly what it is that's causing the jam.
Smearing - fucked photodeveloper/charge roller/transfer roller/fuser/low-voltage power supply (delete as appropriate).
My job is to provide tech support for the office printers we supply to our large account customers. I try not to use the word 'fucked' when dealing with them though.