I have the same problem. I think it the ink caritidge i think down in the bottom of it the ink drys up and even if you refill the caritidge it still can get pass where it dry up on the bottom.
My Lex is 21/2 years old and has been a very good machine. Within the last three or four months, I have twice lost the ability to print in color. Both the printer and computer ink levels suddenly dip from maybe 3/4 full to completely empty. Due to the amount of use and the weight of the cartridge, I can tell it still has ink. I've cleaned the contact points carefully (both cartridge and seating area) to no avail. I've uninstalled and reinstalled drivers (the original that came with our system, and the update CJXP83LE.)
The first time this happened, I bought a new color cartridge, and was able to print in color again. But the new cartridge has done the same: everything's fine; then at about the 3/4 full mark, the color ink level suddenly dips to completely empty, and no more color printing. Both the first time and this time, the amount of use and weight of cartridge tell me I still have ink.
Has the machine just bit the dust, or is there something else I can try to repair it? Thanks so much for your help.