Digital BW, The Print

Luke writes:

> That's one option...dedicating your printer to print
> black and white and replacing the supplied inks with
> a continuous feed ink system that uses only shades of grey.

Now I'm further confused.  Aren't the B&W inks just ordinary cartridges that
replace the standard B&W and color cartridges?

I prefer to dedicate the printer.  I already have a 2000P for color photos,
and it produces so-so black and white.  I'd like something better, though
(without having to spend $100 a pop for B&W prints from a pro lab).