Digital BW, The Print

I always stroke a 1-5 pixel wide black border spaced 1/2" out side the
print area. But lately, I notice the borders running the length of the
paper are getting fuzzy. The ones across the paper remain sharp. I
think this is something new. 

Printing a test target, at 3.6lp/mm the lines across the page are
sharp while the ones going down the page blur together. 

1280, EEM, MIS FSN inks w/ G4 black, Epson driver, perfect nozzle
checks. I can raise the print head from -0- to -1- and it gets a lot
worse but I can't make it better.

Anyone got any clues how to fix?

Bob Michaels