Last week, I switched from pk to mk ink. Printed a number of matte prints. Then, switched back to pk.....total blockage....print nozzle check shows no pattern.
I have worked all weekend calling Epson, trying everything they suggested, plus everything I could find on forums. Best I got was a couple dashes...occasionally....showing up, but basically no black print pattern.
So....ya never know.
Yes, both black ink carts are within expiration dates. I had also used both inks, not one exclusively.