How b/w printing consumes coloured ink

Coloured inkjet printers are commonly seen in offices and households. Sometimes even if we only print black & white documents, we may still find the coloured ink cartridge runs out unexpectedly. It not only is frustrating for users, but also adds to the cost. How could non-coloured printing consume coloured ink from your printer?

What many users don’t realize is that the black texts and patterns printed may not always come from black ink. Most coloured ink cartridges consist of four colours: black, red, blue, and yellow. Some cartridges may not have the black ink box. All other colours could be produced from a combination of these three, including black. In fact, unless users choose B&W or grayscale printing, even black and gray would come from the coloured ink boxes.

To avoid wasting coloured ink for B&W printing, users can go to printer properties to adjust the settings to B&W or grayscale only. This way, black and gray contents would only consume black ink. However, if your cartridge doesn’t have the black ink box, then all colours, including black, would come from the coloured ink.