HP deskjet 920C replaced both ink cartridges and now it prints in

When we see high page volume in these printers, the cleaning ink resorvor needs to be cleaned. It may be even to teh point of stopping the head cleaning carriage from functioning.

It sounds like it is not priming and wiping the head of the cartridges correctly.

You can also try setting the head of the cartridge on a damp warm (water wet) paper towel. If there is ink coming out onto the paper towel you know it is the printer not the cartridge. If you are not seeing any color then I would change the cartridges again.