Digital BW, The Print

I seem to have a heck of a time searching in Yahoo (rather than 
Google), and I could have sword that I have seen this subject 
discussed in this group, but as I cannot find it.....

I just started using the UT7 inks, and I am having printer wheel 
marks on the prints.  I was expecting this with glossy papers, but 
it seems to do the same thing on semi-gloss and luster papers as 
well.  Interstingly, the very first few prints made had no marks at 
all.   Now they all do.

Any ideas as to what might be happening?  As I recall, this is to be 
expected with glossy, but not with semi-gloss or luster.

Thanks.