Clogged Light Black Ink on Epson 7900 (same line on each nozzle check pattern)

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Mark D Segal:
Quote from: Alan Goldhammer on April 21, 2011, 10:15:28 AM

And it also should not be problematic if you do a lot of printing with IGFS (which I know you do ;)) since there is not much dust on that paper relative to a number of others.


Right, and I wonder also how dust would get into the ink supply chain between the cartridge and the print-head. I thought that system would be closed from anything entering from the outside.

Mark

Mark D Segal:
Quote from: Randy Carone on April 21, 2011, 10:33:21 AM

Clogged dampers may be an occasional problem, but the most common damper problem is a pinhole that allows minute amounts of air to seep into the ink line, resulting in a bad nozzle check that can be temporarily alleviated with cleanings but will return shortly after.


Ahah, this starts to sound like something relevant to my issue with the Cyan channel. Perhaps I should re-discuss with Epson if I see it persisting.

Farmer:
Hmmm, not sure how a damper would get a pin hole in it, Randy. Cracking can occur (during transport or usage over time) but it would have to be a pretty specific hole to let air in, since dampers are one of the places air can actually escape/bubbles clear/settle.

Randy Carone:
In the 12+ years I have sold printers, small holes in dampers has been the most common problem with ink delivery. I don't know how the holes are generated - I used the term 'pinhole' loosely - but they do occur. Maybe it is poor quality injection molding, poor quality plastic raw material and small breaks in the ink line where it connect to the damper. Some dampers have an O ring that seals the assembly. I have seen splits in the O ring that have been the source of air bleed but I don't know if all Epson dampers/selectors have the O ring component.

Garnick:
Quote from: Randy Carone on April 21, 2011, 09:40:34 AM

The damper is a small plastic ink reservoir just above the print head that holds a small amount of ink. I just tried to copy a page from a Service Manual pdf with no luck. If you Google 'ink dampers' you should be able to find a picture of one. Most users of Mutoh, Mimaki and Roland replace dampers fairly regularly. They all use Epson heads, but the dampers are not the same as on Epson aqueous printers. If you find a pic it will be immediately obvious what function they perform.


The "dampers" on the X900 series print heads are actually quite different from those on older models. Not sure about the X890 series, but I suspect they have a similar arrangement. On older models each ink line had a separate damper which fed the ink to the print head. On the X900 these are actually called "selectors". There are two ink selectors, attached to a unit(board), which in turn is attached to the back of the print head after it has been installed. Each selector has six ink feed connections, one of which is not used, obviously. Also, each selector receives ink lines in the same order as on the control panel. I've had two replacement heads installed on the 9900 and have been very attentive during the procedure, asking questions along the way as well. I also have the service manual and I'm now looking at it as I write. I believe each selector can be replaced individually but I'm not certain about that. Actually, I imagine the whole assembly(both selectors and board) would be replaced as one unit. That was not one of the questions I asked.

David,
Concerning the warranty issue, I was told by a tech at Epson that they usually have a bit of a "grace period" after the warranty has expired if one is having severe problems, especially if there's a record of previous issues with the printer. This also applies to those who might have planned on extending the warranty but had let it expire without realizing it. I recently extended the warranty on the 9900 because of the issues I've had and I'm glad I did. I am presently awaiting another service call due to a problem I noticed after the last head placement, which was about three weeks ago. Banding in the PK and what appears to be a situation in which the printer is not printing at the resolution I have chosen in the driver. I quite often print at 720dpi when the image allows and that is now looking more like 360 since the new print head. The extended warranty on these printers is NOT inexpensive, but I consider it an important part of doing business. Another insurance policy of sorts I suppose. I would suggest an extension might be the next step if you are still having problems that you can't seem to remedy.

Gary

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