Does the ink mismatch message allow you to push "OK" or "accept" to print?
The 7880/9880 refillable cartridge chips are programmed with information for all color positions, so the printer will actually accept any cartridge in any position (so you have to pay attention to install the carts in the correct channels). This can be helpful if you need to replace a chip, or put a cartridge in a different channel for any reason, and the print driver will display all matte and gloss Media Type settings (instead of just one or the other, depending which black cart/chip is installed). Based on our results over the years, and feedback from customers, it seems that some 7880/9880 printers will correctly accept the MK cartridge/chip in MK mode, but others (possibly depending on the printer's manufacture date) will somehow see the PK information clearer/stronger, which can confuse the printer. Since you are using ConeColor inks, you can either 1. attach an Epson Matte Black cartridge chip to the refill MK cartridge to make the MK cartridge read full/pure MK to be correctly read by the printer as MK, 2. use the printer as is, knowing that you're using MK ink, and select matte/rag paper profiles, and matte media type setting (even though the printer shows a PK cart is installed).
I just did a test print with one of our 7880 printers, using refillable carts, and the black cartridge reads as Photo Black (though it may have always been in PK mode (as they come new), when we installed the refill carts). I was able to select the printer profile and Enhanced Matte setting, and it printed without any mismatch error. Are you able to select a matte Media Type setting and print, or does an error pop up and prevent printing?
Please let me know so I can help you get back to happily printing.,
Best regards~ Dana