This has been resolved!. I reset the printer to its default settings, uninstalled all the Epson drivers, then installed only the Epson driver. All is now good. Similar to The Hat's suggestion.
I can now print out with confidence colour test targets for profiling.
I'm on a mac. I've printed via the following; Epson paper layout, Preview, Air print, Pixelmator epson driver. All these display the magenta issue. Only Gimp and PrintFab (which is on test) print clean.
I find this very odd, since the photo is what I regulary use for testing. This is the first...
I'm not printing borderless. If you look at the above photo you will see a very generous white border of about 35mm on A4 office paper. There you will see magenta ink streaks in the white paper border.
I'm really not doing anything different from my normal way of printing. I haven't encounted...
I have another issue. I'm getting magenta ink overspray on one border of the print. On landscape mode its either at the top or bottom, depending how I orient the print file. Hope you can see what I mean from the Photo. This is just a test print on office paper.
There's a small srew at the bottom of the damper. Unscrewed the damper can be removed. Underneath the damper ther is no valve, but something 'mouth' like, see photo. The nozzle jet check shows empty magenta and photo black sections
Sorry, but I should have been clearer. The photo is of a replcement damper part I found online. I'm still have problems trying free the dampers.
Sorry, for any confusion.