You have to be sure you are getting good suction. Do you see ink pool in the cap when doing a clean cycle?
Is there ink on the wiper blade each time? (That's why you clean it, every time).
Take the bottom cover off and see if you can see ink flow through the 2 tubes. Fill the cap with cleaning fluid and watch what happens when you start it up.
These problems are usually related to not getting enough suction. And that is always below the head.