A Digital Printing Network
Only way I have ever done two sided banners is with adhesive vinyl lettering or printed, applied to both sides of a premade double sided 16 oz. canvas.
No one yet that I've heard of has been able to print on both sides of a banner, you can't use premade because of the grommets...although I have flipped over Vytek banner material (Fellers) and printed on both sides, that is only 13 oz. and not for outdoor durability.
Probably harder to explain than it is to actually do, but here goes...
Using double sided banner material, print the first side / front of the banner (DO NOT center on media) and print with margin marks (NOT the crop marks for pint/lam/cut) with horizontal and vertical both set to 0. Remember which edge of the banner printed first.
Take a look at the edge that printed first, and in the right corner poke a small hole right through the corner of the margin mark itself, just big enough so that you can see it when you flip the banner over. Now I usually wait about an hour or so for the ink to cure a bit before I run it back through, but when you're ready to do the other side, here's what you do. Feed it in, printed side down, so that the edge that printed first is at the front of the platen. It's VERY important that you make sure the media is in there straight (especially if the artwork has any kind of bleed), although I don't have a surefire way of doing that yet (suggestions welcome!).
Once you get your rollers locked down and you're sure it's in there straight, use the arrows to bring out the knife to set your base point. This is where that hole comes in. Position the knife so that the tip is DIRECTLY above the hole. You can check to make sure (on the VS at least, not familiar with other machines) it's directly over it by pushing gently down on the blade holder... the knife should go directly into the hole. Once you've got the tip of the blade and the hole lined up, just set that as your base point and hit print. Bada bing, bada boom, double sided banner!
Great explanation Mike! I have attached a Roland document that goes over basically what you said.
oops! Here is the document.