I am trying to revive a printer that sat at my brothers' place for 2 years or so. It is an Epson R2880. It sat with low ink. I purchased a new set and installed them. I ran a nozzle check and only 4 out of the 8 colors showed up. On the 4 that did, there was a bit of ink missing due to clogs I am assuming so I ran a head cleaning. After eventually running a couple of head cleans the 4 colors show up great but the remaining 4 are still completely missing. Could it be air bubbles and if so how would I go about fixing that. Cheers Jason.