Never give up. Never surrender.
So, last night, I discovered two additional problems that can plague inkjet printers using refillable cartridges.
First, the outlet port on a refillable cartridge can clog. I was under the impression clogs always occurred at the print head. Factory ink cartridges almost never suffer this problem since they arrive vacuum sealed, the printer head punctures the outlet port membrane exactly once, and then the whole thing gets tossed when the ink runs out. Since refillable cartridges get pulled and put back many times, dried pigment ink will eventually build up around the membrane and produce a clog.
Second, refillable cartridges invariably fall over and get tossed around during a refill operation. That often introduces air into the cartridge. Nozzle cleaning usually fixes this problem. However, in a very bad case, air can get trapped in the passage leading to the outlet port, causing an 'air lock' on the cartridge. In this state, it will not print at all.
A cotton swab and some cleaning solution can pretty much deal with an outlet port issue. Removing an 'air lock' requires more work. I ended up sticking all four refillable cartridges in a plastic bag and then using a vacuum to suck all the air out for about 60 seconds. I then blew as hard as I could into the top air port to force the ink down through the vertical channel to the outlet port. That brought back three colors. A second round brought back the black.
At this point the printer works well enough for office use but streaking makes it unsuitable for card models. I will let it sit for a day and go for round 6 (7?) tomorrow.
Anyway, I am leaving this information here in case anyone else ever suffers this problem. In summary, something I did this morning resulted in a significant improvement and I still hate Epson printers.
PS: I have close to $400 invested in this piece of ... equipment. It prints wide format and was specifically purchased for card models. It has never printed anything else. To date, I have completed exactly two card models printed on this thing, and it has produced perhaps 100 usable pages in 4 years. It is my Moby Dick. Oh, hey. Someone should make a card model of him.