my imac can't find my hp 8500 A910 printer

This is the second time I have had this issue.I get a message that the "printer is not connected" and below the image of the item to print in the window it says,

"printing - looking for printer" I know for a fact that the printer is on and connected to the wireless connection I set up.I am going crazy trying to find info to fix this permently.Ithe first time it happend,It started working fine again after a few days,in otherwords I never fixed it lol Any help would be greatly appreciated