Thanks for all your advice/commiseration. Nice to know I'm not alone. My printer itself suggested a fix. It has a button marked "Continue," which it suggested I hold down for five seconds to disable its nonstop Chicken Little warnings that the ink supply is low or nonexistent. It took a couple of tries but it appears to have worked. When the ink supply actually is low the printouts will start to fade. That's always done the trick for me.