Digital BW, The Print

In frustration that I could not elimiate the color cast from B&W prints 
on my Epson 1270, and dismayed with the lack of quality in BO, before 
jumping in and buying the MIS UT FS set, I opened the Epson R200 box I 
had in my basement for the last eight months (a freebee with my D70).

I was stunned by the quality of the BO prints. Obviously all my color 
casts gone overnight, much less bronzing than on the 1270, deep blacks 
(although it needs some tweaking to lessen contrast compared to my 
monitor), and a visually tighter dot pattern with less apparent banding.

What has made me disappointed however, is something I can only describe 
as a tire track. If I print a 10*8 solid grey test print, on the top 
left corner of the print (the edge that exist the printer first), I get 
a tonal difference that is a bar, about 1.5" from the left margin, .5" 
wide and 2.25" high.  Under a loupe is looks indistinguishshable from 
the rest of the print, but to the naked eye looks like a 
stripe/bar/tire track.

I have run alignment, checked the nozzle pattern, changed the driver to 
version 5.50, tried different paper - all to no avail.

Before I attempt to navigate through Epson support lines, has anyone 
experienced such a thing and know of any likely causes.

many thanks
Keith