Note: If you arrive at this page directly from a web search, please see also my more recent adventure with the Epson 3880, which has given me the same exact problems.
I just found out that my Epson 3800 printhead is likely dead, once again, and I will need to get it repaired (not cheap, but still ~1/2 price from getting a new printer). Frankly, at this point buying a new machine is probably a better idea: it costs $650 for repair at Epson, versus $1300 for a new 3880. However, the repair doesn’t give a whole new set of ink cartridges, which run at about $550 by themselves…
Epson says that my printer problem is unusual, and that they have seen it only on a single other 3800 machine so far: my black ink (PK) tank emptys itself in less than a week, even without any printing. Not recognizing this problem right away, I went through several PK cartridges… To compound the problem, this issue is not showing up in the ink counter, which shows the cartridge to be nearly full! I went through 3 PK ink tanks before really understanding the problem. There was no apparent leak anywhere in the printer or around it. In fact, the maintenance tank eventually also became full, demonstrating that the ink was somehow getting leaking through the nozzles (Epson said this is very odd and very unlikely). Thankfully, Epson replaced the “summarily” emptied ink tanks since I had luckily kept them: Epson was able to verify that the tanks are showing full with the electronic ink counters. In any case, prints coming out with this printer issue are too dark and have excess black ink drops depositing on the paper. Not good!!!
UPDATE: The printer ended up going to an electronics recycling company. Thanks to the $400 Epson in effect last September, I was able to get a new Epson 3880 for $750. It has been printing like a champ since then, and I make sure to run at least a weekly printout through it to keep the heads clean and the cartridge tanks shaken to avoid settling in of the pigmented inks.