Hi kindly support folks,
I have an Epson 4900 that is about 11 months old. I have the extended warranty but haven't yet called Epson because I wanted to riddle you first. I've been working with these printers ( 4900, 9900, 9800, 9880, 4800, and 4880 ) for at least 5 years in a lab environment and at artist's studios so I've seen a lot of wild problems and solutions, working both DIY and side-by-side Epson techs.
I've been using Cone Color inks for this printer's working life. On my 4900, I've printed perhaps 1500 or so prints, mostly 8.5x11 b/w proof prints on Epson luster. I also occasionally made 16x20 prints on Harman Warmtone Gloss, Canson Platine, Innova Warm Cotton Gloss, and Hahnemule Photorag Pearl, from rolls and occasionally 17x22 sheets.
I was recently working on printing proofs toward an edition when, at first, I noticed some pizza roller markings on prints on 17x22 sheets. I was working to resolve this issue, when I looked with a 10x loupe and a lightbox and found, to my horror, that the leading side of the prints were perfect, but a banding pattern was appearing about 2/3 of the way through the prints in the 3/4 tones and shadows. Before running the print, I had printed a nozzle check. All clear.
After seeing this banding appear, I ran a printed nozzle check, checked it under the loupe. A couple -- in the PK and C were blocked. I cleaned those channels. It was seemingly fixed on the next printed nozzle check. I ran the print again. Again, the banding appeared part way through the print. I ran a printed nozzle check. Nothing clogged. So then I ran solid black pages and a C M PK LK LLK page to try to run out any air bubbles that might be in the line or the head. The banding appeared in every one of the 8.5x11 black Luster sheets I ran. In the interim, I also re-set the printer's settings and re-aligned the printer. No change.
I've tried printing using the Epson driver in Photoshop, QTR, and ImagePrint, using canned and custom profiles, Epson Luster roll paper, Innova roll paper, and Harman sheets. All to the same result.
I cannot be sure if this is truly a nozzle clog issue or if it is perhaps a paper-feed error, as I've seen both the tell-tale clogged nozzle banding pattern, but on a couple prints where there didn't seem to be a clogged nozzle, I think I see a doubling up of ink density where the head passes overlap slightly.
Any advice would be greatly appreciated as I've wasted about 4 working days and inevitably a lot of paper and ink.