Digital BW, The Print

OK, 

With the following setup I'm getting a strange uneven pattern of ink on the 
paper.  So far I've seen it twice and only when the larger prints, say 14"x10"s. 

 Epson 2200 with OE Matt black on EEM paper.  These are BO prints set with 
"Clayton" settings.  It may do it on other paper or with Ebony too but I don't 
have any PR larger than letter size.

I see it in middle gray and sometimes darker grays (zone III) and it looks as if I 
did a bad job and didn't cover evenly with a can of spray paint.  These aren't 
fine lines or banding, I've had banding and a head clean fixed that.   Just 
looks like the ink head made a few passes w/o enough ink.    I'd say they are 
3/8"s wide or so and sometimes one follows another.  And they are in the 
direction of the ink head travel.

The Matt cart was new today and I did some other prints before I made this 
14x10.  I've never seen it on letter size prints.  I saw something similar on a 
letter size once when i was trying the high speed setting.  On that print it went 
away after I turned off high speed.

Seen it?  Ideas?  

Thanks

Neil