Ink Drop Out Issue - Mimaki JF 1631

[jdwilliams1]

I am having an ink drop out issue. I had a tech come to work on August 6th and since he has left we have slowly seen an issue with yellow ink dropping out. I use to be able to do a head clean or pump motor draw and get it to print ok but by the time it would et to the end of the table the yellow color would drop out almost entirely.


Well here it is two months later and the problem has gotten so bad yellow drops out in about two inches from the start of the print. I have a different tech here just to work on this issue and we thought the yellow head was bad. So we have replaced the head, damper, pump, electric head cable, rubber cap and about everything else associated to the head. Once the ink drops out I do an immediate test print the all the nozzles are almost perfect.


I have attached a couple prints to give you an idea of the issue. Would love some help. Could this be electrical?

 

[WalkerP]

What if you swap ink lines going to the heads just to see if the drop out follows the ink lines or the head? I'm not familiar with that exact model, but that will show you which way to go.

 

[artbot]

those heads are extremely sensitive to viscosity. they need heavy ink. is it a new set of yellow inks? i have custom ink running in my printer which also has the same heads. try some drastic voltage changes to test the results. immediate drop out is usually "blow out". the waveform/voltage can be off in such a way that it can not expel the ink.

 

[WalkerP]

We've run a 3rd party ink in that machine with no trouble and no change to temps/voltages. We've run the same ink in the same heads on an OCE, EFI, and others and had to change the temps, so I agree, those heads can be finicky.

 

[jdwilliams1]

ok we have swapped the cyan and the yellow ink lines and dampers and tried to print them both together and sure enough the color changed to teal ( not as blue as before, it was dropping out slower) suggesting this might be a yellow ink issue?? Would love your thoughts? What would you do next. Here is a picture after swapping yellow and cyan lines and damper. Also after running yellow through the original cyan head, we did our test draw and now the yellow in the test draw is showing quite a few missing nozzles going through the original cyan head. Sorry if this is confusing. I am confused myself.

The bright blue image is when the lines were hooked up correctly and the teal image was after we swapped the yellow line and damper to the cyan head and the cyan line and damper to the yellow head.

 

[jdwilliams1]

We've run a 3rd party ink in that machine with no trouble and no change to temps/voltages. We've run the same ink in the same heads on an OCE, EFI, and others and had to change the temps, so I agree, those heads can be finicky.

WalkerP, where do you buy your 3rd party inks for you jf 1631?

 

[jdwilliams1]

those heads are extremely sensitive to viscosity. they need heavy ink. is it a new set of yellow inks? i have custom ink running in my printer which also has the same heads. try some drastic voltage changes to test the results. immediate drop out is usually "blow out". the waveform/voltage can be off in such a way that it can not expel the ink.

Any other thoughts on this artbot?

As mentioned above we switched the ink lines and dampers and were getting the same issue.

 

[artbot]

when tuning my printer to the new custom inks, i was getting blow out. it would happen in about 10 or so inches. i believe most of me getting these inks to print right was made on the voltage side of things. i think i reduced my voltage drastically. from about 33 to 20's (h700 numbers). i also lowered my temps to stiffen the ink. not knowing if it is the ink, or if the head is not running properly, i'd at least test a block of yellow running at 30% higher and lower voltages on that head and observe behavior. if you see one or the other options make a difference, you can start ruling out things like ink supply.

 

[jdwilliams1]

when tuning my printer to the new custom inks, i was getting blow out. it would happen in about 10 or so inches. i believe most of me getting these inks to print right was made on the voltage side of things. i think i reduced my voltage drastically. from about 33 to 20's (h700 numbers). i also lowered my temps to stiffen the ink. not knowing if it is the ink, or if the head is not running properly, i'd at least test a block of yellow running at 30% higher and lower voltages on that head and observe behavior. if you see one or the other options make a difference, you can start ruling out things like ink supply.

Ok we will play around with voltages, I have to think it is ink related, we have tried multiple heads, dampers, ink pumps, head wires even swapped the cyan and yellow ink lines and the yellow color drops out.

 

[jdwilliams1]

when tuning my printer to the new custom inks, i was getting blow out. it would happen in about 10 or so inches. i believe most of me getting these inks to print right was made on the voltage side of things. i think i reduced my voltage drastically. from about 33 to 20's (h700 numbers). i also lowered my temps to stiffen the ink. not knowing if it is the ink, or if the head is not running properly, i'd at least test a block of yellow running at 30% higher and lower voltages on that head and observe behavior. if you see one or the other options make a difference, you can start ruling out things like ink supply.

My technician has tried everything and is going to leave so I need other options. Does anyone have a tech in the Midwest or should I just call Mimaki at this point?

 

[WalkerP]

Swapping the lines to the heads really only rules out the head, but that's a biggie. You've ruled out damper(s), heads, pumps, voltages, temps, wires.
Sounds like the actual ink lines, any filters, ink cart and ink are remaining.
Did you happen to change Y ink carts recently? New lot of ink?
Could be a micro crack in the ink line, bad seal in a connection/fitting, etc. I've heard so many crazy stories of stuff like this, and some that amazingly work themselves out. I'm never really surprised anymore.

Wouldn't hurt to call Mimaki. I'm not sure what level of service they'll give you, but you've done a lot of troubleshooting and trial and error. Has to be frustrating.

 

[artbot]

especially filters... don't know how filters didn't come up in this discussion. or maybe it did.

 

[jdwilliams1]

Thanks guys for your help. My technician is gone now but I would have thought he would have checked filters...having said that where would they be located on the jf1631?

 

[jdwilliams1]

Regarding the filters, when we hook a syringe to the line going into the damper we can pull ink nicely, then we hook on to the bottom side of the damper and can pull ink nicely. Then when we put everything back together and try to pull ink through the cap station with the head down on the rubber cap, we get very little if any ink.

Also I may have mentioned this. It appears to be a problem that was occurring 2 months ago and slowly got worse, so the text came 3 days ago and put on a new head and the problem has continued to get worse until now the test draw is not putting down any ink

 

[WalkerP]

Let me try to summarize and let us know if it's correct.

-Y head not firing when Y line is connected.
-C channel firing just fine when connected to C line.
-Y head fires OK when C line/damper connected, printing C ink.
-C head does not print when Y line is connected to it.
-Ink seems to flow ok when manually priming from the Y damper.
-Y ink does not want to flow when manually priming from tube coming from the capping station.

Ugh. What happens if you go back , swap the C/Y lines/dampers on top of the heads and try to manually prime from the bottom of the capping station tubes? Is there a difference in resistance? Which one is more difficult to prime?

This is baffling me.

 

[jdwilliams1]

Let me try to summarize and let us know if it's correct.

-Y head not firing when Y line is connected.
-C channel firing just fine when connected to C line.
-Y head fires OK when C line/damper connected, printing C ink.
-C head does not print when Y line is connected to it.
-Ink seems to flow ok when manually priming from the Y damper.
-Y ink does not want to flow when manually priming from tube coming from the capping station.

Ugh. What happens if you go back , swap the C/Y lines/dampers on top of the heads and try to manually prime from the bottom of the capping station tubes? Is there a difference in resistance? Which one is more difficult to prime?

This is baffling me.

LOL. that is correct from what I can that you have written above. I have never had a tech leave without fixing our issues which makes me feel like it must be an ink issue.

WalkerP I am pretty sure my tech used the syringe on the yellow head was attached and e got ink through the head. We even did a test draw and the drop out of nozzles started to occur on the cyan head when trying to get yellow ink through it. I have no clue

 

[WalkerP]

It's sounding more and more like that. 2 ways to tell for certain.
-Load another color ink in that channel (you'll have to swap the bags in the carts). This causes massive headaches of course from color contamination. You'll need to do a thorough flush when converting back to Y.
-Try another ink... PM me if interested...

 

[jdwilliams1]

It's sounding more and more like that. 2 ways to tell for certain.
-Load another color ink in that channel (you'll have to swap the bags in the carts). This causes massive headaches of course from color contamination. You'll need to do a thorough flush when converting back to Y.
-Try another ink... PM me if interested...

We actually swapped the computer chips of a yellow cart to a cyan and now we are not getting any cyan through that head

 

[artbot]

let's all thank mimaki, and for that matter, all of the OEM's for investing millions of dollars in the sensors, chips, and firmware that protect us from using our equipment as we see fit.

 

[WalkerP]

OK, it now does sound like it's the ink channel somewhere from the needle that punctures the septum down to the damper. My guess is there's a clog/kink or leak somewhere in the line. Could be a bad fitting, etc.