Hi. I see you have made exactly the same post in the t-shirt forum where it was suggested you clean the feed rollers.
You also posted on there that your nozzle print checks are ok.
I definitely think the first picture shows tracking from the feed rollers. What paper and inks are you using?
As for the banding, do some more head cleaning, there's definitely an issue with ink supply. I don't have any experience with Brother machines, are the heads even designed to accept sublimation ink? Do you have an ICC profile?