Is my Epson DX3800 printer fixable?

I have an Epson DX3800 printer and I have used the same ink cartridge replacements for ages. This time the red flashing light (out of ink) for the black cartridge flashed and so I changed the cartridge but the light keeps flashing and will not allow me to print. I've shaken the new cartridge, put another new cartridge in, taken all the cartridges out and put them back in, switched it off and on. I checked the printer properties and it tells me all the cartridges are full. Nothing works, it still flashes empty. It still won't print. Is there a solution or do I need a new printer? Help.