Epson ET-2750 prints in grey, but „ignores“ black

[julias]

Hello,
my Epson ET-2750 has Problems.
It prints in grey, but „ignores“ black, it leaves it out. Maybe I can show you a photo with what i mean.
I already cleaned the nozzles and do a power cleaning, filled up the tanks and googled a lot.
maybe someone knows what’s wrong?
greetings, Julia

 

[julias]

this is the test page on pc and printed on b/w to show you what i meant