is it a bubble jet?
if so the nozzles get clogged up if they dont get used alot.
if it has an onscreen display look for Maintenance > head cleaning
if you google how to clean heads and your make and model you can find step by step instructions
depending on how long it sat, it could take a few cleanings. after each cleaning do a nozzle check and it will print out boxes to show you how close you are to having it fixed.