A lot of you will know that genuine printer ink is incredibly expensive. I just paid £21 for a colour cartridge for my Hewlett-Packard. I did take the old cartridge and got it exchanged for a refill. However, the colour wouldn't print. Does anyone know if Hewlett-Packard do this on purpose? I know that the printer knows when you are not putting in a genuine cartridge, however, in past with different printers, I haven't had a problem, the compatible cartridges have always worked. Having said that, I bought some for my Canon 865 and I can't get the black to work