5. Why is it less expensive to maintain an inkjet printer that has a black ink cartridge than one that does not?
If an inkjet printer does not have a black ink cartridge, then it combines all colors of ink to produce a dull black. Having a separate cartridge for black ink means that it prints a true black and, more importantly, does not use the more expensive colored ink. You can replace the black cartridge without also replacing the colored ink cartridge.