JXF200-2513 EX White Banding

[Adam Vreeke]

I am having some trouble with my white ink. I was running and everything was printing great, until the polycarb I was printing bubbled and the material skimmed the printhead. After that I have what appears to be banding in the white, but I have a perfect test print. Normally where it stands now, it wouldn't be an issue, but this is backlit and for a very very very picky customer.

I have tried:
-Pressure Checked
-Air Purge
-Checked for air leaks
-Nozzle Wash

I am just at a loss of where to go from here. Attached are photos from before and after and a test print.

 

[Smoke_Jaguar]

Get a nozzle check and see what it looks like. Is the ink recovering then dropping out? Is it always missing a bunch of nozzles? Helps a ton knowing conditions in troubleshooting.

 

[Adam Vreeke]

Get a nozzle check and see what it looks like. Is the ink recovering then dropping out? Is it always missing a bunch of nozzles? Helps a ton knowing conditions in troubleshooting.

The picture of the nozzle check was done directly after the print and all nozzles were there. Print started off fine, but the problems seem to be at 1 end of the print head (side closer to the control panel). At the time of posting it was consistent through the print. After doing some more tests it got worse. Started off fine and then was very visibly dropping nozzles as the print went on.

Figured out that even though RL7 said ink was at 40% white ink bottles where empty. And currently trying to work the ink through the machine up to the heads to see if it was just pulling air instead of ink.

 

[Smoke_Jaguar]

Yeah, the ink levels are just guesses at best, always good to at least give the bottles a tap or lift as part of daily maintenance. If ink drops and recovers, can be starvation. Subtanks in the non EX version of the JFX200 are great, but they can still start to clog over time causing the filter screens to take longer and longer. Pump filters can also do similar. I think if you press Enter when printing, it will show subtank levels. Might be a different key, not at my shop at the moment to check.

 

[Solventinkjet]

I'd check pressures and run an air purge. That's usually the first step in figuring out these dropout issues.

 

[MikePro]

is a head soak a possibility?
I always got clogged nozzles after a headstrike on my solvent printer that seemed to clear-up after a long soak.

 

[Adam Vreeke]

Yeah, the ink levels are just guesses at best, always good to at least give the bottles a tap or lift as part of daily maintenance. If ink drops and recovers, can be starvation. Subtanks in the non EX version of the JFX200 are great, but they can still start to clog over time causing the filter screens to take longer and longer. Pump filters can also do similar. I think if you press Enter when printing, it will show subtank levels. Might be a different key, not at my shop at the moment to check.

I replaced the W/W/Cl/Pr sub tank just about a year ago. I am unsure when or if ever any filters or ink pumps have been changed, we have only had this used machine for about 1.5 years.

I'd check pressures and run an air purge. That's usually the first step in figuring out these dropout issues.

These were all done already before posting as I know that is usually that place to start. I just did a second air purge, but haven't tested if it has helped yet or not.

 

[Smoke_Jaguar]

Head soak (nozzle wash in Mimaki parlance) can help, but the Gen5 heads they use are big honking nozzles and UV ink doesn't tend to dry (cure) unless exposed to UV or intense light over time. Usually related to flow.

 

[Smoke_Jaguar]

Air purges tend to be pretty much a once-every-few-months kind of a thing. Or if the printer sat a long time. At least in my experience.

 

[Adam Vreeke]

is a head soak a possibility?
I always got clogged nozzles after a headstrike on my solvent printer that seemed to clear-up after a long soak.

Yes, I did a shorter nozzle wash (Mimaki's version of soaking)

 

[Adam Vreeke]

Air purges tend to be pretty much a once-every-few-months kind of a thing. Or if the printer sat a long time. At least in my experience.

Maybe my thoughts on how the machine works is incorrect. I figured if the white ink bottle was empty, but I am still printing white that it would suck up air, or at least get more air mixed in with ink than normal. And those air bubbles are pulled out near the head where you would do an air purge. Is this correct, or is that just the last line of defense and most air gets pulled out in a different part of the machine?

 

[Smoke_Jaguar]

There is a float sensor in the bottle tank, if it drops to low, it stops pumping to prevent air from being pumped into the system and pauses printing.

 

[MikePro]

Yes, I did a shorter nozzle wash (Mimaki's version of soaking)

niiice. yeah my mimaki had a headsoak option BUT i would extend the time by running it and then powering-down the machine to allow it to soak overnight.

 

[Smoke_Jaguar]

Overnight soaks can be bad for the heads by eating into the glue that holds the nozzle plate on. If you are using the new maintenance fluid #16, that stuff can even dissolve chemical resistant tubing.