Inkjet printer only has 3 colours in the cartridge,how does it print black aswell ?

i have a lexmark z735, it only has one cartridge with cyan majenta and yellow colours.how does it print black aswellInkjet printer only has 3 colours in the cartridge,how does it print black aswell ?
Lexmark claims to have formulated the color inks so that they combine to yield ';black.'; so when it combines all three colours its supposed to give the colour black. hope this helpsInkjet printer only has 3 colours in the cartridge,how does it print black aswell ?
i suppose it mixes the other colors.
The printer uses the mixture of colors to print in Black.
Mixing all the colors together produces black. That's why most printers these days include a black cartridge - it saves you from using 3x the ink to make black.