Alas, what seemed like a better tube route didn’t work any better and, in fact, the generous loop snagged crosswise between the print head box and the R380’s frame. So I deployed the big diagonal cutters and a nasty end cutter to chop a channel through the side of the box:
As far as I can tell, the thin section above the reinforcing gridwork exists specifically to get in the way of routing CISS tubes, but I suppose it could be just for pretty.
With the tubes coming directly off the top of the tanks and folding neatly as the print head moves under the frame, I could rearrange the supports to hold the tubes in a nearly straight line throughout their motion:
So far, so good.
Although the yellow ink now feeds properly and all the nozzles appear up on the test page, the printer output has an overall cyan tinge that gave the Annual Christmas Letter a gloomy aspect. Maybe the latest bottle of cheap Light Cyan ink isn’t quite as light as it should be?