Digital BW, The Print

I am doing some trial prints on a friend's 1160 using Piezo Carbon 
Sepia (a CIS) and the ICC profiles. On the prints there are two 
columns (about 2 3/4 inches apart) of small black dots.  Each dot is 
about 1 inch from the next one in line and the column extends nearly 
the length of the paper (8 1/2 x 11).  Sort of like this
  .        .


  .        .


  .        .

I have tried head cleanings (the nozzle check is fine), alignments, 
windex paper towel under the print head, and the windex-misted sheet 
of paper through the printer.  The dots don't show up on a sheet 
that is just fed through the printer.  Only on sheets that are 
printed - different types of paper, different thicknesses, different 
files.

Any ideas/suggestions?  Thanks.