I used to have a similar problem thats one reason why I changed printers as the one I had didnt have seperate cartridges and if red ran out I had to change the whole lot as they werent seperate it was very expensive just to print in black and white as it always used some colour very frustrating when your black ink cartridge is still full but because a colour has run out you cant print in black. But since changing to a printer scanner I have now encountered different problems.
Love pam