Ultimately, you will have to replace the cartridges, all of them.
The issue here is that the printer when new comes with a cartridge that is only partly filled, just enough to get the system up and running.
Even if you are not printing in color, the color ink is still used for normal maintenance procedure of priming and cleaning the head which happens automatically, so they do get used up, and the more you print black, the more it will run the overall cleaning process and still use the colors too.
If the printer is only a few weeks old, you may be better off returning it and buying a different model. A black only laser, if you don't need color, is quite inexpensive and will give you a lot more print mileage for your money. I can recommend some options for you if you'd like, but otherwise you will need to replace the inks when it prompts you too. You'll only be able to get by a short while ignoring it before the printer will shut down and refuse to function until they are replaced.
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