Why are my colored ink cartridges showing depleted when I print in black ink only?

[AmeliaLynne]

I use the very expensive 950XL ink cartridges for black ink and the 951 for the three colored cartridges.  Even though I am printing in black ink only, the system is showing that my ink cartridges are depleting and the printer stops printing unless I replace them.  The ink is not being used and I'm annowed that I have to purchase colored ink cartridges when I'm not printing in color.

[Kumar0307]

@AmeliaLynne

Welcome to the HP Support Community!

• I assume you are using a HP Officejet series printer by the Ink cartridge numbers you specified. These printers are designed in such a way that it also uses color inks while printing in black to form a perfect black. This is called as K-fortification in printer terms.
• This is done to balance the amount of ink consumption among all 4 ink cartridges.
• You will have to replace the depleted ink cartridge to continue printing. Even if you are printing only in black.
• For more information about cartridge yields and ink use, click here

I hope this helps you understand why the printer is asking you to replace the depleted color ink cartridge.

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