A few days ago I posted that my six year old 1400 is having banding issues. Head cleaning did not help, alignments did not help. Today I spent a bit more time with the machine and I have a resolution.
The printer in question is using the UT-14 ink set. I printed a copy of the MIS Purge 6 test page. This showed that the banding was coming from the yellow cartridge. In UT-14 yellow is a clear gloss optimizer which should not be printing at all on matte paper, which is what I have been printing on.
Nevertheless, I pulled the yellow cartridge and examined it. There was clearly black ink collecting in the nozzle of the cartridge where the remains of the cellophane sealer were. Using a small sharp knife, I completely removed all of the remaining cellophane and then cleaned both the spout of the cartridge and the port of the printer using Cone's Piezio Flush. Following this, I printed a yellow-only purge page, which came out with only minimal evidence of faint banding. I then printed a six-color test page, which printed perfectly in all colors.
Following this I printed a full 11 x 17 of the image that had banding problems and got a perfect print. Looks like the old 1400 is back in business.