trouble with printer

I use Windows 7 Ultimate connected to an HP Deskjet F2200 All-In -One series printer/scanner. I am having intermittent problems with my printer.Yesterday I printed something smoothly, an hour later I attempted to print a letter and all I got was blank sheets of paper coming through. I've checked for paper jams, connections etc., but no amount of cajoling will make the darned thing print when it doesn't feel like it.
Can anyone explain and help>
Thank you
Auntievirus