QTR-Quadtone RIP

HELLO GROUP,

I have had some very good results with QTR since I purchased it
approximately 18 months ago. However, I have also experienced some
problems along the way. On occasion I have noticed what I can only
describe as a sort of "Splotching" effect in some prints. What this
amounts to is a rather irregular pattern of increased density. Almost
as if I were to take a brush and paint in more density in a haphazard
way. Of course this effect will always render the print unusable. The
other part of this anomaly is that when I do a reprint, it will
sometimes not appear at all, or it will manifest itself in a
completely different area of the image. Yesterday I encountered a
problem I haven't noticed for a while, although it has been there on
occasion. I was trying to print an 11x14 Warm Sepia. Down one side and
not as noticeably on the other side was what I would describe as a
sort of banding. The "bands", again, were all of a plus density
nature, very diffused, and approximately 1/8th of an inch in width. I
did 2 prints with basically the same results. I then printed the image
through the Epson driver and had no problem at all. Of course I
couldn't obtain the effect was trying to achieve with QTR, but at
least I did finally get a print.  

Let me clarify one thing. These problems are happening in what seems
to be a totally random way. Both while trying to achieve a neutral
print and while utilizing one or more of "color" curves provided. And
again, as I mentioned previously, the second and third prints from the
same file may or may not show the problem. I am using a 7600 with MK
and I always make sure the nozzles are clear before printing. All of
these prints are done on Epson Enhanced Matte Paper. I have no problem
with the native Epson driver, either when printing color or a neutral
image. I very much like the possibilities provided with QTR and the
neutrality of the images, but if I can't find a solution to this
situation, I may have to take it out of my workflow. I DO NOT want to
do that, so I hope someone will be able to offer a bit of advice
concerning this problem.

Thank you,
Gary