If you are seeing banding in your print at standard, high, or highest modes:

Step 1 is to make sure your media type is set correctly for the media that is loaded and that you are at least running at Standard Print quality or higher (NOT DRAFT).  

Step 2 is to run a successful nozzle check, if there is nothing wrong with the nozzles then 

Step 3 is to run a print quality adjustment print on the printer.  SEE THIS LINK for instructions.