You would have to check your color management and things like overprint settings or the ink levels of the color components. Streaking is usually a sign of areas getting oversaturated and the automatic adjustments in the printer driver being unable to compensate. and then of course other factors may figure in like banding inherent in using gradients across large areas, out of gamut issues for certain colors and what have you. You'd have to be much more specific about all of that for anyone to even begin to advise specifically...
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