I have an HP PSC 1410v All-in-One inkjet printer which uses HP21 black ink cartridges. They don't last very long and are expensive to buy. I have been told the HP56 black ink cartridge holds almost 3 times the amount of ink and is the exact same dimensions as the HP21. If I replace my HP21 cartridge with a HP56 cartridge, will it work right? I can't get an answer from HP and I hate to spend the money only to find out the HP56 won't work in my printer. Please help!