Digital BW, The Print

Hi -
 Just started using MIS inks with a Niagara CFS in an Epson 
1270 and am noticing teeny-weeny white lines running through 
the print, parallel to the movement of the print-head.
 Is this microbanding? I'd been under the impression that 
microbanding was BLACK lines...
 Whenever I run test patterns the lines are all OK.So would 
popping on an OEM cartridge set for while be of any use?
 Thanks!

f