QTR-Quadtone RIP

hi

I have problem with my printer (epson stylus pro 9600) of very large
orizontal banding betwen density 60 up to 90, with any kind of paper
(galerie gold silk, harman gloss fb al, hahnemuhle baryta).
we use ink Ut7 with rechargeble cardriges, we perform several hard
cleaning and head allignement.
also we linearize all the paper with Print Fix Pro and Quad Tone Rip.
the ink set is been bought on August 2007.

thank you

gianni romano