I have never had a head plug completely. The printer was doing fine with PK. I printed a manual test pattern which had every dash in the right place. I then purged with piezoflush and got a perfect manual test pattern.
I switched to MK after replacing that cart with Piezoflush. Now my black position is totally blocked.
I Did several internet searches and have struck out so far on remedying this problem.
Can anyone help .?