It is well known that HP charges customers "through the nose" for the ink for their printers. Is the reason Epson came up with their alternate solution. You ought to try giving your customers a better deal on ink.
HP is now forcing Firmware Updates after 11 pm with a timer on waiting for a yes/no to update BUT now it appears that if you do not respond in a minutes THEY DEFAULT TO YES and lock the printer down if non-HP cartages are tring to be used!!