9890 head clean failure

I’ve been getting black streaks on the borders when printing 24" - Doesn’t happen to small - 8.5x11 paper. Cleaned the heads maybe 15-20 times using the folded, saturated paper towel method. Almost as much ink (mostly black/blue) on the 20th time as the first. Was using water/alcohol method. Have just ordered Piezo flush and will use it next, but what happened with water/alcohol method doesn’t make sense. Any ideas about my problem? Thanks.

This is probably not the head but a funky roller or platen pad that needs cleaning.


Can you tell me more about where they are and how to clean them? Thanks.