Blocked yellow channel - bad pump assembly?

My Epson 7800 has a blocked yellow channel (with Shade 1 Warm Neutral gloss black) that I can’t open. It’s also showing deflected nozzles in a few other channels that jump around after cleanings.

This is what has been tried so far, in chronological order:
[li]many nozzle cleaning and checks
[/li][li]power clean
[/li][li]cleaning capping station, wiper blade, and parking head on capping station with Piezoflush overnight
[/li][li]letting printhead sit on Bounty white towel soaked in Piezoflush
[/li][li]damper replacement.
[/li][li]pulling Piezoflush (from a different cartridge than the Y cartridge with Piezography ink) through Y ink line to the head
[/li][li]2 power cleans after damper replacement to pressurize system/put Piezoflush through the Y nozzle in head
[/li][li]printing 4 - 17" x 40" purge image for yellow channel via QTR with Piezoflush cart installed in the yellow channel. This prints some extremely faint lines at the beginning of the print, but after a few inches, nothing comes out. Also, there are some very small Piezoflush spatters on the paper.
[/li][li]letting this sit overnight with Piezoflush in the Y ink line and head.

The machine was running Piezography 2 inks (matte in the PK slot and photo black in the Yellow slot). It has original capping station, pump assembly, and print head. Now it has new dampers, but prior to this problem I think it had the originals.

After damper replacement, I was able to successfully make matte prints with normal results for a day, but am now getting deflected nozzles in other shades enough to show bad banding with matte prints. This morning I have clear nozzle checks in every channel, except Y which is completely missing.

My local technician (via phone) doesn’t think its head failure, but suggested that maybe the pump is failing and not creating enough pressure in the system. Would a bad pump cause this? He also suggested a bad cartridge, but I’ve tried a different cart filled with Piezoflush and that didn’t print either.

Can you tell me where you resourced your dampers from? Where they OEM dampers or aftermarket?

You replaced all of the dampers after you installed the flush cartridge in the Yellow channel and that is what is still in the Yellow channel correct? So there hasn’t been any other inks in the Y channel since you replaced the damper, except the flush?


Oh and great detailed write up of the steps you have taken thus far! Makes my job that much easier and diagnosing that much quicker!

Yes, all dampers (aftermarket from DTG Printer Parts) were replaced at once.

After damper replacement, I did a power clean with Piezography ink (not Piezoflush) in yellow channel. The yellow channel was still blocked. Then I remembered your recent newsletter about maintenance and “scouring the ink line” with Piezoflush, letting it sit in the head, etc.

I opened up the printer again, accessed the dampers, and removed the yellow damper. Then I inserted the Piezoflush cartridge into Y slot, used a syringe to draw the Piezography ink out until Piezoflush came through, and reattached the yellow damper. Reassembled the printer and ran 2 power cleans, tried the purge images, letting the print head sit overnight.

This is the exact same concern we experienced in our 9880’s in the studio, the culprit turned out to be the Dampers that were aftermarket and after careful inspection, we found they had small lint type fragments in screens. When we ran the WN1 through them it clogged and we could NOT resolve it with flush. We replaced the dampers several time with the same results, we just discovered the source of our frustrations was the aftermarket damper(s)! We had our WN1 ink tested and it passed with flying colors, so all roads lead to the damper.

The other channels may not see a problem using the aftermarket damper, as we haven’t had any problems with other channels. BUT you should replace your Y damper with an OEM we recommend using as a resource for these parts.

Is Inkjetmall no longer selling dampers? I clicked on the link from your recent maintenance newsletter and it says "item no longer available"on the IJM site.

We are selling dampers, but they do not work effectively with WN1 ink, that is why I directed you to compass micro for this particular Damper. The others I do not suspect will have a problem, I would only replace the Y.

I have a new genuine OEM Epson damper installed now for WN1 Yellow channel. Did my best to prime the line and pull Piezoflush into the damper before reinstalling it. If only changing one damper, is it necessary to do a power clean? Or have all the channels lost pressure in this process? If I only need to pressurize the Y channel, is this possible by printing a purge image for Y channel?

You will need to perform a Power clean to ensure the air is out of the line, even though you already primed your line there may be some residual air left behind which will cause you headaches if you don’t get it out completely.

OK, a power clean has been done and I’m still having a severe blockage in the yellow channel. Any other ideas? I won’t have enough ink to do any more power cleans until more arrives on Wednesday.

It isn’t quit clear to me, do you still have the flush cart in the Y channel or the WN1?

The WN1. Flushing cartridge became empty after the weekend.

So, you didn’t verify a good NC after replacing the damper in the Y position with Flush, correct?

How old is the WN1 you are using?
Has the cartridge been shaken to disperse the pigments?
Are you getting anything out of this channel or is a complete blockage?

So, you didn’t verify a good NC after replacing the damper in the Y position with Flush, correct?
Yes, I didn’t get a good NC. But Piezoflush did sit in there over the weekend. I did a some normal head cleanings and printed purge images that had very faint pink lines coming through. So it would seem flush solution made it to the head and sat there for 48 hours.

How old is the WN1 you are using?
I bought it about 3 weeks ago. Lot # 140725
Has the cartridge been shaken to disperse the pigments?
Are you getting anything out of this channel or is a complete blockage?
Some ink…see attached.

You have several missing nozzles in other channels as well, But I am not convinced doing another Power Clean is going to miraculously clear up your Y channel. If you didn’t get a good NC with flush installed, then I’m not sure if it will come back or not, you may have more to this story still. The next step would be to replace the Capping station aka.Pump Assembly and the Wiper blade, I suggest you get these parts at Compass Micro, Make sure you clean the bottom of the print head thoroughly when you replace these parts as well, these parts are not too overly expensive (a lot less then a head) and could be causing this problem. Best of luck! Fingers crossed-Kelly

I will try that. BTW the link you sent is for 7880 parts not 7800- heads up in case anyone else follows that link and almost purchases a 7880 part instead of 7800 part - they have different part numbers. Also, the 7800 part is almost $100 more.

Thanks for letting me know, I corrected it to link the 7800 Pump Assembly.

You can also try clearing the clog out of the Y channel in the print head by using a Cleaning Kit attachment. You will remove the damper and ink line and apply the cleaning attachment directly on the head, put a paper towel under the head to collect the flush and push the Piezoflush through gently. If you find resistance while depressing the plunger, you can pull back UP on the plunger and let go, doing this a few times until you dislodge the clog. At which point you can push the Piezoflush fluid through the head without any resistance, effectively clearing the blockage in the head channel. You can purchase the head cleaning kit here

I would do this in combination with the Pump Assembly and Wiper blade replacement, you should see results!

Thanks for the suggestions with the cleaning kit and updated link to the pump assembly.

The pump cap assembly looks like it contains several of the items IJM recommends replacing every few years (main/right capping station and flushing box)…is that correct?

Compass Micro seems to sell all the pieces separately as well.

I read your instructions for using the kit (in your post from 3/31/15 and the instructions posted here (which is for small format printers). Does a Piezoflush cartridge need to be installed on the Y line in the ink bay? Or am I pushing piezoflush in/out of the head with the cleaning attachment only?

I’m assuming after all that, another power clean is needed to pressurize the system.

You don’t need to install the flush cart, you are going to use the head attachment directly on the head itself. You will remove the damper assembly to access the head directly, then push the Piezoflush through the head cleaning attachment onto a paper towel that you will place underneath the print head. Does this make sense? Afterwards, yes you will have to perform one more power clean cycle and you should be good to go!

Yes, the Pump Assembly comes as a complete assembly, to include the wiper blade I do believe. That is why they call it an “Assembly” it has the pump, the capping (parking) pad, wiper blade. Yes, this is the right Pump assembly that I linked on the past thread.

Let me know how it turns out, I’m sending good vibes your way! Kelly

Thanks Kelly - it confusing because Compass Micro told me that the Pump Cap Assembly is different than the flushing box and capping station, and I’d have to order those parts in addition to the pump cap assembly. But the pictures of the pump cap assembly sure look like the flushing box and cap station are included in it. I’m sure I’ll figure it out.