The color ink cartridge is expended even though I print in black only. Why does this happen?

• To keep the printhead clear and ready to print, the printer uses a small amount of ink from all the cartridges whenever it prints.

  Epson printers contain a permanent printhead that needs to be charged with all colors to work. Even when you are printing in grayscale or black only, a small amount of color ink is used to keep the printhead charged. The printhead needs to be kept charged to prevent air bubbles from entering and damaging the printhead.

  Therefore, once one of the cartridges is expended, the printer signals you to replace the cartridge for printing to continue.