The black cartridge (PGBK) won't print corectly though I've adjusted the print heads meticulously. The problem remained even after I changed the cartridge for a new one and both cleaned and deep cleaned it.
Is this a hardware problem which require service or is it something that I can fix myself?
Attaching sheet #1 from the manual print head adjustment routine and a also the Nozzle Check Pattern.
Notice the distorted pattern on the Nozzle Check Pattern.
Manual print head adjustment, page 1:
Nozzle Check Pattern: