seems that I'm having exactely the same problem with just one little (but may be relevant) difference...
Hi Lorenz,
It certainly "looks" like the same issue.
To make sure it is, would you please try to print a solid black square of 10 x 10 cm.
( Or like the example on this page:
http://members.upc.nl/reppel/E9900.html#file )
720 x 1440 @ unidirectional on a fine art paper like Epson Smooth Fine Art using Mat or Photoblack.
To see what happens during printingprocess you have to open the cover. ( Or use a flashlight to see what happens. )
Because the printingprocess will stop when you open the cover you need to insert two small pieces of cardboard in the locks to get the printingprocess going again.
Look for any wavelike pattern during the printingprocess.
Clearly visible on this video:
http://members.upc.nl/reppel/E9900.html#videoIf you see comparable results it would be a great help if you could make a video of this and post it on youtube and provide us with a link in this topic.
In my case I am convinced it is not a software / RIP issue. ( Epson NL agrees ). It is ofcourse not a humidity issue. ( My studio is always @ 40% minimal )
In my case Epson NL is troubleshooting this on my machine in my time.(!)
For two months now....
The next thing they are going to do is to replace the NVRAM on my machine with the NVRAM from a 9900 that is printing flawless.. according to Epson. [http://members.upc.nl/reppel/E9900_NVRAM.html]
If you want to prevent Epson Germany trying to troubleshoot this issue on your machine ( they will start by replacing the printhead ),
make sure you have a video of the printing process.
When your printingprocess flaw is comparable to mine, refer Epson Germany to Epson NL. Case: card.nl / Stilleprint Dordrecht / EHQ-090591569 / KJFE003379
Or this topic.
Lorenz, please keep us up to date on this issue.
As I will do.
Untill I have a 9900 that is printing flawless....
Hartelijke Groet van Matthijs