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RobH
6-Mar-2016, 06:11
Hi,

I have a strange nozzle problem.

When I do a nozzle check, light magenta is totally missing. Based on that one would conclude that the nozzles for that color are clogged.

But when I do a test print of an image with all 7 specific colors, light magenta is printed as normal.

Have a look at the attached image.

Anyone has an explanation for this problem?

Best regards,

Rob.
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Andrew O'Neill
6-Mar-2016, 11:42
Weird. Have you tried printing an image? I know it's difficult to tell if the LM is being laid down, but if the print looks good.... maybe there's some circuitry problem just when you do a nozzle check...

Peter De Smidt
6-Mar-2016, 11:51
A nozzle check uses a tiny amount of ink. It might be the case that there is a small vacuum leak in the LM system, but it's not enough to cause a problem with regular printing. That's just a wild guess, though.

RobH
6-Mar-2016, 14:08
Weird. Have you tried printing an image? I know it's difficult to tell if the LM is being laid down, but if the print looks good.... maybe there's some circuitry problem just when you do a nozzle check...

Thanks for looking at this. Yes, I did print a test image and it does not look good, some colors are weird. But that could also be caused by bad ink since all cartridges are several years past their date...

RobH
6-Mar-2016, 14:16
A nozzle check uses a tiny amount of ink. It might be the case that there is a small vacuum leak in the LM system, but it's not enough to cause a problem with regular printing. That's just a wild guess, though.

Thanks for your answer. That was also my best guess and the only logical explanation I could come up with.

Now I did a test print with som tiny and thin lines in LM-color, both vertical and horizontal, and they turn up on my paper, strange... These lines were shorter than the ones in the nozzle test pattern and equally thin.

Any suggestion on how to test for such a leak?

Edit 1: I added a photo of the lines I printed, together with a section of the standard nozzle test print underneath. I printed in magenta and light magenta, and they both turned out fine.
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Edit 2: I added another photo. This time I printed the nozzle check pattern from my pc after I downloaded an image from the Epson manual. I printed the image both vertically and horizontally, and they both came out well. In the photo you see them underneath the nozzle check print I did straight afterwards, and there again the magenta is missing. Earlier I thougt the missing color was light magenta but it is actually magenta.
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onnect17
6-Mar-2016, 20:59
The normal nozzle check from the console is the way to go. As other members mentioned it could be a vacuum leak or the line blocked. If you feel comfortable opening the printer then pull the dumper for that color and verify the line is not blocked and the parts are in good working condition. If you are located in the New England area I can help you (for non-commercial work). Still will cost you the mileage and a six pack. :-)

RobH
8-Mar-2016, 07:56
Hi, thanks for the offer, but being based in Norway it's gonna be a lot of milage ;)

I would like to understand what is happening before opening the printer. Nothing seems to be blocked since all colors print. And it does not seem to be a vacuum leak since small amounts are being printed when it is done by printing an image. Any other suggestions? I am an engineer, so I will be able to do the work myself.

onnect17
8-Mar-2016, 09:42
Rob, IMHO the easiest and right way to know how each channel and nozzle is operating properly is via the printer console, printing a "nozzle check", as the one on the top of the first image you posted.

It seems to me one channel is totally missing (magenta perhaps?). Search online for the service manual for the printer so you can open it and pull the damper in question.



Hi, thanks for the offer, but being based in Norway it's gonna be a lot of milage ;)

I would like to understand what is happening before opening the printer. Nothing seems to be blocked since all colors print. And it does not seem to be a vacuum leak since small amounts are being printed when it is done by printing an image. Any other suggestions? I am an engineer, so I will be able to do the work myself.

barnacle
8-Mar-2016, 15:46
I know nothing of this printer, but it does occur to me that it is possible, given that the printer knows one channel has a problem, that it is compensating for this in an actual image (and producing a possibly only slightly degraded image). Onnect's advice to believe the printer console makes sense.

Neil

RobH
9-Mar-2016, 12:46
Problem solved! :)

I dismantled the printer, excellent description here. (http://www.americaninkjetsystems2.com/support/how_to_repair_a_7600_9600_page1.html)

I could now easily check the lines across their whole length, and the magenta line had large air pockets. The lines are by the way marked with their color code all the way.

I removed the magenta damper, and it was empty. Flushed and cleaned it with cleaning liquid and tested if I could pull liquid through and that worked. Used a syringe to create vacuum at the printer head side of the damper.

I then put the line back ond the damper, put the damper in place, and pulled ink all the way through, again with a syringe at the printer head side of the damper, until I did not see airpockets anywhere in the line. This way I filled the line and the damper with ink. Put back the damper holder onto the printer head and did som nozzle checks and nozzle cleaning cycles. I got some magenta spots but was still far away from a perfect pattern. The normal cleaning cycles did not give any improvement, but the power cleaning cycle from the printers menu did! After each power cycle the result got a bit better, and now it prints 90 % of the magenta test pattern. I had to do 5 power cycles to get here. Before that I did at least 10 normal cleaning cycles without satisfying results.

I will continue with some power cycles until it is all perfect. (and yes, these power cycles consume a lot of ink...)

Printing my test image shows a big improvement. It already looks like it should, and there are no more color errors.

The printer looks well built and is easy servicable. Looking forward to using it.

Thanks to all for the advice!

onnect17
9-Mar-2016, 13:38
Glad to hear you got it working!

I also use a cleaner suggested by others online, (ie Windex without amonia) for all the cleaning. If the epson ink is old (> 5 years past expiration) then I add it 1 or 2 ml of Photo-flo 200 for each 100ml of ink in the cartridge to "soft" the ink. Most of the ink I use in my printer is >10 years past the expiration and without any issues. If you are refilling the cartridges make sure the ink has the right viscosity and pull any air out. If using non-epson ink, you should filter it first using a damper.

Suction from the line is OK but never push anything towards the print head. You could damage it.

Also, using windex, clean the wiper and the rubber around the print-head cap. Spray some windex in the center and let it soft the ink in the pad. That should improve the suction during the cleaning cycle.

If you are concerned about the amount of ink wasted then you can flush the all the lines with a ink base. Using a spare set of cartridges, fill them with a mix 25% Glycerin + 10% Photo-Flo + Distilled water. I also add it 1 or 2 ml of black ink to each cartridge so I can see the patterns with a "nozzle check". Once you get the printer operating properly then bring back the color cartridges.

I use the same base for mixing the B&W inks in a 9600 converted to BW.

Good luck!



Problem solved! :)

I dismantled the printer, excellent description here. (http://www.americaninkjetsystems2.com/support/how_to_repair_a_7600_9600_page1.html)

I could now easily check the lines across their whole length, and the magenta line had large air pockets. The lines are by the way marked with their color code all the way.

I removed the magenta damper, and it was empty. Flushed and cleaned it with cleaning liquid and tested if I could pull liquid through and that worked. Used a syringe to create vacuum at the printer head side of the damper.

I then put the line back ond the damper, put the damper in place, and pulled ink all the way through, again with a syringe at the printer head side of the damper, until I did not see airpockets anywhere in the line. This way I filled the line and the damper with ink. Put back the damper holder onto the printer head and did som nozzle checks and nozzle cleaning cycles. I got some magenta spots but was still far away from a perfect pattern. The normal cleaning cycles did not give any improvement, but the power cleaning cycle from the printers menu did! After each power cycle the result got a bit better, and now it prints 90 % of the magenta test pattern. I had to do 5 power cycles to get here. Before that I did at least 10 normal cleaning cycles without satisfying results.

I will continue with some power cycles until it is all perfect. (and yes, these power cycles consume a lot of ink...)

Printing my test image shows a big improvement. It already looks like it should, and there are no more color errors.

The printer looks well built and is easy servicable. Looking forward to using it.

Thanks to all for the advice!

RobH
10-Mar-2016, 00:14
Some really good tips here, thanks! I will follow your advice.

Walter Foscari
11-Mar-2016, 18:11
Hopefully your issue is solved. For future reference you might want to take a look at the epson wide format yahoo group. Lots of knowledge about this stuff.

https://groups.yahoo.com/neo/groups/EpsonWideFormat/info

Walter