This is my own bodge to fix a paper feed problem that many people seem to have with older HP Photosmart All-In-One printers.
It seems to work well
Take a piece of springy steel wire. You can get this from hardware or model shops.
Bend it to the shape in the photos. The grid on the paper is one inch between the thick blue lines.
Clip it in place as per the photo. You should have enough pressure so that
the paper feeds OK but not too much so that you can still insert the paper OK.
http://www.stevematt.f9.co.uk/