HP's New Cartridge Design- Inside the New HP 920 Regular-Sized Cartridges

For 920 cartridges, HP modified some of their cartridge designs. Let's take a look at the normal startup black cartridge. We're not talking about this XL cartridge. Let's take a look at a startup cartridge. What a surprise that it has the opening between the front and back chambers.

Furthermore, please see the inkstand on the wall of the back chamber. It means the HP is using the back chamber just like the XL cartridges. This is good news because we can refill regular or startup black by filling the back chamber.

For the color startup cartridges, HP expanded the sponge to make it a lot longer. Now the back chamber is gone, and the whole cartridge is a big piece of sponge. Therefore, for the color startup cartridges, we should use a front chamber refill. For the black startup cartridges, we can use either front chamber refill or back chamber refill.