I did some additonal test with printing one special image (intended as a Cyanotype negative). Unfortunately I can't get very good quality. As I really don't see any problems in the original I'll almost think now that this is a problem of the printer :-(
So I tested printing at higher resolution of the original (hasn't any influence at all—I think 360ppi is the outmost the printer is able to reproduce at all). But a lower resolution of the printer (1440x1440dpi instead of 2880x1440dpi) still gives the macrobanding and adds a microbanding too (or maybe it's just the lower resolution).
I did print to a file too and did an unprint. The resulting ppm looks a bit funny. I suppose every pixel represents an ink dot—but the black's missing?! And I don't see any stripes in the yellow, magenta, or cyan (it looks pretty random to me).
So now I'm thinking about bying a new R200… The head alignment procedure doesn't get too perfect (but here I'm not sure if you won't see some slight lines anytime anyway). Maybe because of the problems with the curvature of the foils I'm printing on I got the head damaged?
Oh—if you want to have a look at my 'original' tests.
Hi there, you want to send the information to the printer at 720dpi as this is the native resolution of the printer. The driver will resize all reslutions sent to it to 720dpi which it then sends over the USB cable.
The problem is the R200 driver is awful at resizing. Try printing a grid of horizontal black lines, one pixl high with one pixl between them, at different resolutions, e.g 180dpi, 300dpi, 360dpi and see the result, it is very poor, 180dpi may look ok, but the others wont, I now send all my prints using photoshop at 720dpi and have no microbanding issues anymore.
Just give the printer driver the resultion it wants to see. See if it helps.