Need Help Mutoh 1204 black ink static issue?

Hello all.
I have been trying to figure out this issue for a while now..I have attached a pic to better explain the issue. This is not always how it looks... I am getting very inconsistent black "overspray" only when I print black next to white(or no ink areas). I know if looks like there is ink from the rollers, but that it no the case. I have cleaned them along with the print head and maint station. When I do a nozzle check its always has a couple of the black small lines missing. They are not always the same lines missing, but seem to be towards the top of the nozzle check. If I had to guess what it is I would have to say maybe some of the black nozzles are plugging and spraying weird? One mutoh tech that I talked to mentioned it might have something to do with static? I have done all the cleaning possible to the print head except soak the print head face in solvent (tech said not to). Any other color or if there is color next to the black its perfect. I have tried 6 different medias with the same result. I greatly appreciate any advice!

 

The lines do line up with the rollers. The lines don't appear until the print head makes a pass over the media. There is always white(with no ink) media between where the print head is passing and the rollers. The rollers have been cleaned and completely dry. Its just weird this only occurs with the black ink.. All other colors are perfect. and black is good when there is color against it. Its just when there is no color or just white media.