Lexmark E120 black cartridge

In their determination to keep you purchasing their ink whether you like it or not, Lexmark has circuitry built into their ink cartridges that based on measured use tell the printer when the cartridge theoretically should be empty, whether it is or not.

In the case of the black cartridge they are somewhat more lenient than in the case of the color cartridge. Eventually, when the circuitry tells the printer that the black cartridge should be empty it will continue to be refillable, and work, but will present the owner with annoying messages ranging from "you're using an unauthentic cartridge" to other things. The best thing to do in this case is to check the box that pops up telling it not to continue giving you the annoying messages. This works, but eventually may start again, after which you again check the box telling it to stop. It's quite livable though.

In the case of the color cartridge the built in circuitry will eventually tell the printer that the cartridge is empty, even if it's not because you have properly refilled it, and it simply will not function any longer. You've just wasted your ink. Natually they don't want to see you destroy your printer, which costs less than purchasing only two of their 2400% profit ink cartridges. Good luck.