Digital BW, The Print

Hi all,

Printing with Epson 7500 and MIS UT1.

Any idea of what this can be?
When printing 100% black suddenly a banding occurs in the paper feed direction.
At approx every 4,5 mm there is a ca 1mm slightly 
lighter band, very diffuse edges.
Hardly visible in the beginning (closest to head) 
but at the other end of the paper very visible.
Changed roll with another number - same banding.

Bi-D and Head alignment are ok.
Head slant is ok.
Nozzle check is ok.
Aluminium profile and decoding strip cleaned and Alu profiled oiled.
Looks like the ball bearing wheels are turning correctly.

Printed a MIS purge file horizontal. 60 cm wide and each color ca 3cm.
The black showed this strange banding.
The first 20-30 cm almost not visible and then more and more visible.

When taking a closer look you can detect the banding in C (dark grey) as well.
However, when selecting Black in the driver 
instead of Color there is no visible banding.
Looks like it could be a little error that adds in "RGB-black"?
Only from the dark color head?
You can't see anything in M, maybe to light?
But what kind of error, have had a lot of other 
banding problems but this something very new.

Any suggestions are welcome

Hans
-- 
Atelier Pictoform
Chia N-Löfqvist & Hans Nohlberg
Hedåsgatan 5
SE-412 53 Göteborg
SWEDEN

+46  (0)31181414
Mobile: 073 974 44 24
(Besök/visit Hedåsgatan 6)

http://www.pictoform.nu
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