Why are there two black ink cartridge's in the Canon MP630?

I've run out of the thicker one, and I will of course go out and replace it, but I was just wondering what the other black, thinner cartridge did? It's full, like the printer's never used it. The printer didn't come with much of a guide book and canon's site isn't helping.





Can someone tell me what it does and how to use it?Why are there two black ink cartridge's in the Canon MP630?
One cartridge is for photo paper, the other one is for plain paper. If you go in the paper type, you probably have it set to glossy paper. change it to normal paper. The other cartrdige will kick in.


But you will have to replace the bigger cartrdige just the same if you need to print on glossy.

laons