After installed a CISS system into my Canon IX4000 I'm suffering now from microbanding in deep blue sky colours, especially in large area's of the same dark blue sky. I already printed several print head nozzle checks to see if any nozzle has clogged, but none visible.
The strange thing is when printing light blue skyes with or without clouds, there is no microbanding at all (or my eyes can't see it). All other colours are ok. I also tried the 4-colour testpage of Neil Slade and I find out that the cyan block looked banded.
A manual print head alignment didn't fix the problem. Tried several print head cleaning cycles as well, both normal and deep cleaning, with no improvement at all.