These printers have a paper guide accessible by removing the rear cover, it's like a foot long piece of plastic with several triangular shapes on it, and it clips in either side. It should have a tiny spring on the RH side as you look at the back, located where the guide clips in. If this is missing you will have your paper spewing out the back no matter what settings you put in! Also there is a 1cm long plastic tab on this guide also on the RH side that fits in a slot designed for it, you will get the same fault if this is broken off as commonly happens.