It sounds like the head is blocked. Are you using aftermarket inks? as this can cause damage to print heads (which is almost irreversible without replacing the head, which is so expensive buying another printer is often a batter option)
Assuming you are not using aftermarket inks, or that this happened after a warm day or a period of sitting, try doing a head clean.
This can either be done via the printers menu or via printer properties on the computer. It sometimes needs to be done several times. More information here:
http://h30434.www3.hp.com/t5/Inkjet-Printing/C310a-photsmart-black-print-head-blocked/td-p/857711