Sometimes the obvious thing is correct - yes, it needs a black ink cartridge. I'm surprised you managed to go through the cartridge alignment procedure correctly.
Here is a set up manual to guide the cartridge installation
Samsung Galaxy S8 review
1995-2015: How technology has changed the world in 20 years
This 2D animation about monsters is illustrated in a Van Gogh painterly style
How to get WWDC 2017 tickets
Synology invites you to visit them at Insomnia on 26th – 29th August. Book your tickets now and visit Synology.