QTR-Quadtone RIP

Last evening I was doing some test prints with QTR and I thought I detected a dotted line 
across one of the prints. Well I detected same with a magnifying glass. The first thought that 
came to me was "pizza wheel" marks. Has any one else experienced this problem. I know 
some of the older Epson printers did this and MIS had a tutorial to correct it. Just checked MIS 
but found nothing. Any suggestions. I've already got a CIS installed so I'm not concerned with 
mods if necessary.

Regards, Marvin