QTR-Quadtone RIP

Hi all,

I am trying to make digital negatives for platinum print
using  Win7 version of QTR-Gui (direct print )  + Epson R3000 +
Pictorico TPS-100 ( 8.5 x11' transparency sheet).
It is  working great except one issue.

I see  banding  patterns on top 1 inch area and probably half inch in
the bottom too.
Changing image data file to other one, including just step tablet
does not solve the issue.

When using Epson driver, the banding disappears.
So I believe this is not ink head cleaning nor data file issue.
The  curve set up I use is based on Ron Reeder's book
( Digital Negatives for palladium and other alternative processes)
Figure 23 or 24.)
So the curve itself is proved to work for other printers.

I saw  that R2880   also has the same problem as reported below,
http://tech.groups.yahoo.com/group/QuadtoneRIP/message/9745

Only way to avoid this banding  looks like using a bigger sheet ( such
as 13x19 )
to leave top and bottom not printed ?  which is costly and not efficient...

Has anyone seen this with R3000 or any other printers ?
Is there anyway  better  to solve this issue ?

Hiroshi