hp 6978 not printing black/ color

problems with printer printing grey. so this is running though a printer maintenance a few times.

[@ferencszathmary9689]

Have the same 6978 unit since 5 years, never an issue with it. I did run the head cleaning, and the paper coming out had only the colors on. I repeated about 4 times. Same outcome. The cartridge is new, before that was another good one. Probably I have to throw the printer out. The bay of the cartridge is also clean.