The colors on my print outs from my HP Officejet Pro 8610 are appearing very dark. It was printing fine a week ago. Levels are near full. I've cleaned the print head the max of 3 times. And I've aligned the print head as well.
Update
Not saying that this was it but it may be the cause. It doesn't look like there is any ink anywhere on the cartridge.
There is black ink on the nozzles of the other cartridges which are all official HP brand.