Ink drop out??? PLEASE help

[bboukari]

Mutoh Falcon II Outdoor 64"
I'm at my wits end with this printer.




Ok, Please see the attached pictures.
What I have appears to be an ink drop out on the Magenta head. Let me start by saying I've done coffee filter soaks, I've replaced dampers, caps, pumps.

Here are the details. I noticed this drop out especially because I was printing a job that used most of the width of the printer and in some places has heavy ink usage. The drop out seems to happen after about 3-6 inches into the job. To duplicate the symptoms and try to troubleshoot, I printed the same job, but inserted four color bars between the two images I was printing. I know that Onyx does not send the the black bar as 100% black, even though that's what I made it in the file. I know this because I can see some slight banding in the black and possibly the cyan. But most noticeably, I see the banding on the magenta.

Questions set 1:
Is it fair to conclude that this in fact an ink drop out?
If so, is this occurring on the magenta head?

Here's what I've done:

I have replaced the black head.
I have replaced the pumps that serve the Black/Cyan and Magenta/Yellow

I have replaced dampers on the black and magenta heads, although I'm not confident that I've done the damper replacement properly.

The dampers I installed were high-flow dampers, in other words, they had wider screens rather than the little round screen inside.

I have also replaced the caps at the capping station with new ones, then a different set of new ones because I thought maybe the first caps I bought were cheaply made and not of good quality.

I then went back to older caps because none of the print heads performed well on a nozzle check after the printer sat off and unused over a three-day weekend. In fact, they were terrible and unusable.

I have taken the black and magenta dampers off again and sucked ink back into them, but again, I'm not sure I've done this properly.

Question set 2:
Are the wider-screened dampers okay to use?
Are the smaller-screened dampers okay to use?
Where else could my problem be?
How do I know if the caps are sealing well and/or giving the ink a good prime before printing commences?

Yesterday, I ordered an entire set of new dampers and am awaiting their arrival.

I'm sorry to be long-winded, but I wanted to get as many relevant facts in as I could recall.

Any and all help and guidance is greatly appreciated.

-Bryan

 

[J Hill Designs]

other possibilities include cracked/damage printhead manifold, cracked/damaged o-rings at any of the ink tube connections from the head back to carts, or possibly clogged lines down from capping to waste

 

[CRD]

Do you have a picture of the machine selftest nozzle check?

Paco

 

[bboukari]

nozzle check

Here are the nozzle checks. The first nozzle check shows the magenta a LITTLE WHILE BEFORE the print where there's a drop out. The next magenta was done JUST BEFORE the print where the ink drops out. Also, Keep in mind that I'm printing that large print where the banding happens in a 4-pass full overlap mode in Onyx. The banding also occurs when I print it in single-pass or 2-pass, although the frequency is different.

 

[CRD]

Maybe I am mistaken but if you miss nozzles you cant print without banding. :-(
Your single pass printing (test print of the machine) should be OK otherwise it will never be 100%. Looks like the Magenta is missing nozzles and the the cyan not.
Depeding in the number of passes and the position of the missing nozzles you can still have banding.

Paco

 

[heyskull]

Yes I agree the nozzles are not helping your issues.
But I reckon you have an issue with the encoder disk because it is not constant and looks like it reappears in the same area.
Our Valuejet does this from time to time and it is because the disk is warped and the sensor is touching the disk.
This is probably a similair setup on the falcon.

SC

 

[bboukari]

Regarding the encoder disc theory, wouldn't it be happening right at the beginning of the job as well? Why does it always start banding a few inches AFTER the job starts? Also, I don't think I get banding on less intense jobs. I can also say that I printed a 9 inch X 25 inch logo that didn't contain red, but did contain orange and it didn't band at all.
Again, I only called it an ink drop out because that's the only way I can describe it, but I am not at all sure about it, so I very much appreciate folks thinking outside of the box.
-B

 

[CRD]

If it always happens after the start of a print you would suspect inkflow is not sufficient enough and maybe before that point the mising nozzles are not visible enough until the inkflow is getting less. Problem is you do not know what happens during printing if more nozzles stop to work and after a rest are reappearing again in the next printout. You already replaced the dampers so............more troubleshooting to be performed.

Paco

 

[wunder]

change the Printheads ! there is to many deflections on it to solve your problem !!! And the best way to use the NEW Valve DAMPER and not the original !!!

and i think your printheads totally dirty ...clean it from the printingside !


regards
wunder

 

[bboukari]

Ok gang,
I'm still working on this issue. If I replace the o-rings, dampers, head manifold and gasket, caps and pumps, what else can I do?

My next move was to replace the ink tubing and o-rings from the "y" branch above the dampers all the way back to the steel tubing and then replace the o-ring where the steel tube connects to the ink cartridge bay. Is there anything else I should do?

Just as a recap, I'm wondering if it were an encoder disc issue, wouldn't the dropout/banding occur right at the beginning of the job rather than always happening 12-18 inches into the job where there's intense ink usage? Also, could a bad print head just start having ink dropout a few feet into a job but print fine otherwise.

-Bryan

 

[CRD]

Try printing a job with white spaces of some inches between some horizontal CYMK colors bands machine wide.
What happens if you print full color cymk horizontal band ( not vertical ) of small witdh lets say 20 cm does the banding appear at same distance from the first start of the print.

Paco

 

[bboukari]

Try printing a job with white spaces of some inches between some horizontal CYMK colors bands machine wide.
What happens if you print full color cymk horizontal band ( not vertical ) of small witdh lets say 20 cm does the banding appear at same distance from the first start of the print.

Paco

Paco,
So are you saying to print two sets of bands like this?
======Printer========Printer=========Printer======
KKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKK
CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
YYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY

KKKKKKKKKKKK
CCCCCCCCCCC
MMMMMMMMMM
YYYYYYYYYYYYYY

Should I do both of these sets in one continuous job? How much space between each COLOR and how much space between each SET?
ALSO, I just want to say, that when I create an image of CMYK bars, RipCenter still uses other colors in each bar. In other words, I know that the Black bar also contains Magenta in it. I haven't figured out how to force RipCenter to sent full Black and only Black and so on with the other colors.

Again, I want to reiterate that your continued assistance is very much appreciated.
-Bryan

 

[CRD]

You have PM.I will make a test file.

 

[CRD]

Brian,
First try the 30 cm test file.

Then the 110 cm file.

https://dl.dropboxusercontent.com/u/14421088/cymk test file 30 cm.psd
https://dl.dropboxusercontent.com/u/14421088/cymk test file 110 cm.psd

Paco

 

[Robert M]

ink

Are you using bulk ink. When the banding starts is there still ink in the dampers? Unless you are getting air into your lines, the ink lines should not be the problem.
To check the cap top, pull on the like from the individual cap with a syringe, you should only see ink, no air. I think it is ink or print head related.

 

[bboukari]

Are you using bulk ink. When the banding starts is there still ink in the dampers? Unless you are getting air into your lines, the ink lines should not be the problem.
To check the cap top, pull on the like from the individual cap with a syringe, you should only see ink, no air. I think it is ink or print head related.

Robert,
I'm not using bulk ink. I'm using Mutoh brand inks. I've used a syringe before to pull from the pump side and I definitely DON'T recall getting just ink, but I'll try again. As I recall, there was resistance, but I wasn't pulling just ink through the line.
-Bryan

 

[bovegas]

This is what you have to do. Put syringe on capping station and see when you pull if there is hissing noise. If there is hissing noise and you can pull it easy, it means that air is getting inside, probably through o rings. Try to use o rings that were installed in printer originally. If there is still hissing noise put a drop of cleaning solution where tube meets damper and see if cleaning solution disappear when you pull syringe. What you got is ink starvation and there is leak somewhere. You can do quick test to make sure my theory is right. Swap dampers together with ink lines from head that is working to non working and see what happens. If there is still drop out than its something else.

 

[artbot]

great advice bovegas. also if you hear a hissing noise have a partner press upwards on the capping station into the print heads while pulling a vacuum. if you hear
the hissing noise get quieter or go silent then you know that your caps aren't targeting your heads either most likely high enough, or possible off target and riding the SS edge
of the print head. in order to check for targeting, paint the rim of the caps with black ink. now gently park the heads on the caps. now unpark them to the left. with a flash
light look at the bottom of the heads to see if the imprint of the black ink is properly centered on the platen of the heads. diagnosing a printer has to be a very methodical scientific
process of elimination. not trying to be a jerk. but all these parts being put on the printer is exhausting and although something may have fixed it. the real repair may have been free other
than a bit of dividing and conquering the ink train.

 

[bovegas]

Thanks Artbot, I have forget to mention extra step you have mentioned regarding upward pressing cap station. He has good test print so it seems capping station is working ok. I can bet its the leak around o rings. When you install new o rings put drop of cleaning solution on them. Probably original problem started because metal spring on old damper was not working anymore causing ink starvation. He replaced with new damper with slightly bigger o rings and there is air leak, so problem continued...

 

[bovegas]

One more thing. If you look closely tube that goes to damper, you might see dent on tube where o ring is. If thats the case shorter the tube lets say 1/8". This dent around the tube can cause o ring not seating properly. You can do a test disconnecting tube from damper, than pull syringe from capping station and put finger on the damper where tube was. If there is hissing noise than o ring under the damper(where damper meets head manifold) is having air leak. If there is no air leak than o ring on top of the damper causing air leak.