When I switch my printer on to use it, it works as normal. (Its an Epson Stylus Photo R540).
If I don't use it for a while and then try to print, the Epson Status monitor comes up but with the ink levels greyed out and it just sits there failing to print.
To get it to work I have to switch the printer off and back on again. If I am printing several jobs with only a short delay between each there is not a problem. It is only if the printer is not used for say 5 minutes or longer that this happens.