Digital BW, The Print

Im fairly new to this, so if this is a common problem that has been covered - please just 
point me in the right direction. 

Im printing with the MIS UTFSN cartrides (Matte Black) on an Epson 1280. The paper is 
Epson EM. 

The problem Im having is with images where one area has heavy deep black shadows. 
'Below' these areas I am getting dark lines after the dark section(s). By below, I mean the 
section the print head covers after it has covered the dark section. It is as if the black ink 
flow (or another dark black) does not shut down as fas as it should. By the time the print 
head is back at the other side of the print and starting its next run, the problem is gone 
until the dark section is covered again.

This is hard to explain - if someone knows what Im talking about, please let me know. 
Otherwise, I'll post an image on Monday.

Thank youall for your time,  Ben Z