Anyone who's used this breed of printer from Epson knows the drill: there's a tiny fear every time you run a nozzle check print. Could this be the one? Could this be the start of a head clog, or ink delivery problem of other cause, from which the machine never recovers?
This is scary because we've all read accounts of exactly that happening. One color channel prints an incomplete test pattern, it gets worse with time, and no cleanings, whether standard or "powerful", resolve the problem. The "clog" is permanent. As with hard-drive failures, it's not a matter of if it will happen, but when. These machines become our personal sword of Damocles. Some people call for service, while some attempt the repairs themselves. These are complex machines; a bad nozzle check can have many causes, sometimes multiple causes. There's never a cheap fix. Some people simply scrap their machine or sell it for whatever value its parts might have.
Early this month I got a job to print 17 small prints and two larger ones. The small prints were of a black-and-white photo and would be made on letter-size sheets of Epson luster paper. The larger prints would be on Epson luster (24-inch roll).
The 7900 had been idle for 28 days. As usual I started with a nozzle check. I found scattered tiny areas of the VM and PK channels missing, so I ran a standard cleaning of the C/VM pair and the PK/LK pair. Another nozzle check showed the black channel at 100%, but VM was now missing fully half of the check pattern, much worse than before the cleaning. Next I ran a "powerful" cleaning of the C/VM pair. Another nozzle check showed a half-dozen tiny bits of the pattern still missing.
To meet the client's requirements I needed to print right away, so I did. While it's common for even tiny flaws in ink delivery to be obvious in prints, in this case the prints looked good. I suspect the VM channel cleared as I was printing the black-and-white image, but I didn't run a nozzle check after the job to confirm.
Nine days later I set up to print another job. The nozzle check showed most of the VM channel missing. Because I rarely get a good result from standard cleanings, I started with a powerful cleaning of the C/VM pair. This left a tiny missing spot in the middle of the VM channel. Once again, I ran the print job, finding no problems with the output.
Since that job I've run three more, on the 13th, 15th, and 19th of December. The nozzle checks have all been perfect, including the VM channel.
Looking back through the nozzle check prints I'd run in the past several months I see the VM channel has been troublesome far more often than any other. It's a concern, something to watch. But to put this into context, most of my nozzle check prints show no problems with any channel. "Clogs" happen, but they aren't typical. Perhaps they only happen when I'm in a hurry.
--Jay
