Digital BW, The Print

Hi guys -

I seem to be having some problems with banding in the black ink on my
brand-new 1280. 

I don't seem to be getting banding on any other ink color, which makes
me wonder if maybe it's a problem with the ink or head, since it
probably isn't a problem with the advance mechanism. 

The bands are _really_ small - so much so that it's taken me a great
deal of prints to be sure that it's happening. 

I'm printing with VM ink on EAM using the 1280-mac curves (Adobe RGB,
1440, PQIJ, Auto...) High-speed is disabled. 

Should I send the printer back? Is it a problem with the ink I'm
using? Do I have a clog?

-Charley