Is your paper correctly inserted and the guides correctly set ?
Is the printer picking up the paper ok or is it misfeeding or not gripping occasionally ?
What paper are you using ? (weight, coatings ?)
Are you fanning the paper stack before loading ? Have you tried turning the stack over ?
Was it always like this ? Or did it recently start happening ? (e.g. did you clear a paperjam incorrectly by tugging ? )
Have you looked up and followed roller cleaning instructions ?
see also...
HP Deskjet F2400 All-in-One series- HP Deskjet F2400 Series All-in-One Printers - The Printer Does Not Pick Up or Feed Paper - c02143938 - HP Business Support Center