I recently had a banding issue that I got resolved through an onsite service call and I think everyone should be aware of this solution...
Like many of the other people I have read about in various forums, I had a banding issue that I was finding no easy solution for. Using every possible troubleshooting suggestion listed in the manual produced no results. Reading about other user experiences validated some of my issues, but I also found lots of speculation, over analysis, and frustration, with little information that made my issue go away.
So let me explain what did the trick...
When the tech arrived, the first thing he did was open the cover and examine something he called the "Timing Fence" with a small flashlight. This is a translucent black tinted strip, about as wide as a piece of scotch tape, that runs parallel to the print head's belt about an inch above it, but sits close to the metal housing of the printer's interior (see attached pics, or links below for non-forum members).
Within moments, he pointed exactly to where he thought the banding was occurring, which in fact, did line up with what I was experiencing on my prints. He explained that the Timing Fence (also referred to in Epson's part list as the CR Encoder Scale, part no. EN1894) is etched with tiny lines closely spaced together and that there's a sensor on the print head which uses these lines to keep track of each row of ink being laid down. If this strip has any dirt, smudges, dried ink, etc.. on it, then the sensor will be unable to read this, causing a jitter or imperfection of some sort in the print. If anyone is familiar with woodworking, it's like using a router with a template that has a notch or burr on it. That bump would be transferred to the finished work piece, which is the same thing that was happening in my prints.
SO HERE'S WHAT HE DID...
He took some Windex, sprayed it on a lint free paper towel (like the Rags In A Box product from Home Depot) and wiped it down real well. Immediately, one of the areas of banding disappeared. In the one area that remained we noticed that although it had been wiped down, the strip itself had popped out of its plastic holder and was sitting in front of it. He took it and carefully seated it back into place behind the two end tabs and lined up the open slot area on the strip with the black plastic catch piece of the holder. Problem solved completely.
I should say that before you attempt any of this yourself, this is a very fragile part. Don't go after this if you are heavy handed because a crease or bend in this could mean having to get a new one and could be more time sidelined. But if you're careful and work slowly are pay attention this will save you $275 easily.
I know a lot of the manual's suggestions will probably work for most things, but this was just one of those things that seemed elusive to detection and as a result, incredibly frustrating. Hopefully, this solution will become more widely recognized as another way of troubleshooting your printer banding issues.
Link to pics for non-forum members:http://flic.kr/p/auoPsLhttp://flic.kr/p/auoPu3