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

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Ernst Dinkla:
Quote from: Randy Carone on April 21, 2011, 11:35:35 AM

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.


With the older models: The seals of the damper connectors are the most likely place to let air in or with enough ink pressure ink out (seldom). The membrane (most likely PET) thermo/ultrasonic welded on the polyethylene damper house could have a leak at the weld, cleaning them with a syringe had that risk of pulling them apart there. Older dampers showed less flexibility in the membrane and the small stainless steel spring inside could in theory puncture the membrane in time. The membrane is there to equalise ink pressure on feeding and demand and adapt the ink pressure to the atmospheric pressure, at least on the the older Epsons including some pressurised models. It could be that it changed in newer models and another ink pressure control is used.

It wouldn't surprise me if the new damper model includes a sensor that actuates a valve in the ink line when the ink pressure/feed near the head drops, the opened valve to fill the ink buffer again. Something like that existed on the 10000 model but there internally in the head assembly.

With OEM carts the risk to get filth in the lines in negligible but pigment settling (say coagulation) in the ink can build up a barrier on the damper's sieve in time or with infrequent printer use. Inks have improved though.

Air in the head shows when the bad nozzles change in quantity and place. Frequent cleanings may not help at all, sometimes a night's rest does more. Thermal heads suffer less of air as the nozzle channel is less complicated and the thermal pump can still function with some air enclosed, pizo pumps need fluid to create the pumping action, any air there will just act as an air spring and the ink isn't pumped.

met vriendelijke groeten, Ernst

Try: http://groups.yahoo.com/group/Wide_Inkjet_Printers/

worldburger:
So I called Epson Pro support again, they sent out a notification to Decision One (who had done the service call 1.5 years ago on this printer).  They gave me an estimate.  $450ish incl labor for the pump and cap assembly repair.

As this is a documented issue I've had, Epson said I could talk to customer service about reimbursement or them covering it.  I'll call them tomorrow about it.

As far as maintenance I can do myself, what is to do with the dampers?  Where do you buy these?  Is there anything else I can do to try and fix this myself?  On my 4000 I'd just put some cleaning solution in a syringe and pump some onto the place the print head sits when it's parked, but I don't even know what that'd be on the 7900 because there seems to be two places it goes when it parks.  Ideas?

Thanks (and stumped),
David

Mark D Segal:
Quote from: worldburger on April 21, 2011, 10:09:15 PM

So I called Epson Pro support again, they sent out a notification to Decision One (who had done the service call 1.5 years ago on this printer).  They gave me an estimate.  $450ish incl labor for the pump and cap assembly repair.

As this is a documented issue I've had, Epson said I could talk to customer service about reimbursement or them covering it.  I'll call them tomorrow about it.

As far as maintenance I can do myself, what is to do with the dampers?  Where do you buy these?  Is there anything else I can do to try and fix this myself?  On my 4000 I'd just put some cleaning solution in a syringe and pump some onto the place the print head sits when it's parked, but I don't even know what that'd be on the 7900 because there seems to be two places it goes when it parks.  Ideas?

Thanks (and stumped),
David


Two points here, both of which point to doing nothing:

(a) no clarity on what the cause of the problem really is;
(b) if you are into a discussion with Epson about them covering the issue, don't muddy the waters by tinkering with the machinery yourself.

My two cents-worth.

Garnick:
Quote from: worldburger on April 21, 2011, 10:09:15 PM

So I called Epson Pro support again, they sent out a notification to Decision One (who had done the service call 1.5 years ago on this printer).  They gave me an estimate.  $450ish incl labor for the pump and cap assembly repair.

As this is a documented issue I've had, Epson said I could talk to customer service about reimbursement or them covering it.  I'll call them tomorrow about it.

As far as maintenance I can do myself, what is to do with the dampers?  Where do you buy these?  Is there anything else I can do to try and fix this myself?  On my 4000 I'd just put some cleaning solution in a syringe and pump some onto the place the print head sits when it's parked, but I don't even know what that'd be on the 7900 because there seems to be two places it goes when it parks.  Ideas?



David,

From what I've seen during service calls on the 9900 and in the Service Manual and Field Repair Guide, it would seem that there are few areas of these printers that are easily accessible to the user. As an example, to access the pump/capping station and wiper blade for removal on the 7600, it was a rather simple matter of removing the right end cover. To reach that point on the 9900 requires a much more time consuming and complicated procedure. And of course the pump/cap station assembly for the 9900 is also considerably more sophisticated. However, once there I don't believe the installation is much more involved than on older models. It's my opinion that this may very well be the easiest of all components to replace on the X900 series printers, and perhaps ironically, one of the most important. Also, it  would seem to be one of the lesser expensive parts to replace. However, one must have access to the proper manuals before attempting this procedure. As the last tech to work on my 9900 said, "my goodness, there certainly are a lot of screws to be removed". Of course I am quoting from memory and not verbatim. However, that statement did not instill in me a lot of confidence in his knowledge of this printer, as I have stated in a recent post on this forum. I hope you have some good luck with Epson concerning this matter. Also, you should consider calling Epson after the service has been completed and plead your case for replacement of some of the ink you have wasted trying to solve this matter yourself. They are usually quite compliant in that regard, especially in warranty situations. Another reason to consider a warranty extension, especially for these models.

Good luck and keep us "posted"!

Gary

Thelo:
Quote from: worldburger on April 21, 2011, 08:57:09 AM

I've done multiple cleanings (regular, pairs, power), put it in maintenance/service modes and done CL2, CL3, and CL4 cleanings, and printed MANY nozzle check patterns.


Have You tried supersonic cleaning in service mode?

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