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Mimaki JV300-160 techs are stumped

SEBLY

New Member
Hi. I have a Mimaki JV300-160. Not printing every day and not hard on the machine. Trying to figure out why I'm losing magenta on head 1 after a few prints. Nozzle wash/ soft cleaning cycle seems to bring almost everything back on head 1, but the first test print will sometimes look a little dirty. Second test print, looks better but still missing the lower right of column 8 magenta on head 1. I'll start a few prints. They look decent. Do a test print after that and magenta is partially gone on head 1 both magenta columns. For a few months I haven't been able to bring back magenta entirely on column 8 head 1 lower right. Head 2 started to become a mess about a year after it was replaced. I gave up on it. Seems that the issues always start at the lower right corner of of the test prints on both heads. I've started replacing dampers (2 dampers - the other 6 have never been replaced in 3 years), replaced the cap heads, using Triangle ink recommended by dealer, did nozzle wash overnight with shutting down power to the machine, tech support from dealer had me adjusting cap settings, flushing position, air pull position... nothing seems to work. They're now saying the print heads are probably delaminating so it's time for a new machine or a $7000 repair. Anyone out there have any thoughts on this one?
 

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Solventinkjet

DIY Printer Fixing Guide
It looks like you're getting a good amount of cross contamination in almost every channel. That would point towards a bad cap top or poor drainage in the maintenance system. I would pop the cap tops off and flush cleaning solution through the pump to make sure it's not fully or partially clogged. Even with new cap tops, if the tubes are partially clogged, they drain too slow and cause contamination.

Other than that, I would change all of the dampers so they are closer to each other in age. Each color in your machine is connected somewhere back in the machine so if you have a new damper for one and an old damper for the other, it can throw the pressure off. Basically the new damper overpowers the old one and causes ink flow issues.

It could be the heads at the end of the day. If nothing else works that's usually the case.
 

Black Star

Not A New Member
I agree with the bad cap top. I have a JV33 and I had issues the very first time I replaced the cap top. The print head and the cap top weren't lining up and I kept losing a channel. I ended up shimming something in there to move the cap top over just slightly so there was proper suction. I haven't had that issue happen since but it was puzzling why everything wasn't lining up.
 

mbasch

New Member
I would guess bad cap or bad pump. We had a similar issue on one of ours. After spending weeks and thousands of dollars on a tech who didn't fix it, we figure out the capping station just wasn't sealing properly.
 

SEBLY

New Member
Apologies for the delay. And thank you for the feedback. It's really appreciated. I read through the comments and started investigating. I replaced both caps within the past few weeks, but the problem has been the same before and after. Based on SolventInkjets advice I inspected the maintenance system. I had mentioned to my tech that the lines down below the cap area never seem to do anything, but he said the pump sounds like it's working just fine. (In his defense, he was remote and we were working through videos, photos and phone calls.) Last night I started pulling all the lines below the carriage station area and running a thin wire through them. You'll see the long pieces of black ink in the photo. They look like black tubes. Obviously a problem that may help solve the underlying issue. Is it a good idea to replace all the lines with new ones? I've noticed that the 3 lines feeding from the Washing Liquid cartridge don't seem to do anything. One of those lines is still clogged... I couldn't get my wire all the way through. With the Test Print, you can see that Head 1 looks really good after the printer sits for a few days without any use. If I do a soft clean... problems start up. I'm guessing this is all a combination of issues with the dampers needing replacement and some replacement tubing or potentially parts within the maintenance/pump system?
 

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Solventinkjet

DIY Printer Fixing Guide
You should be able to see ink flowing through those lines during the pump cycle. The fact that you pulled dry ink out of the tubes means they are probably clogged in other places. I would disconnect the tubes from the cap top and try to push cleaning solution through the pump and into the waste tank. That will tell you if there are any more clogs. Also, those little plastic pieces that connect the cap top tubes to the pump tube tend to clog as well. You can use a needle to poke those clogs out. Pumps rarely fail on these machine as long as they aren't clogged. So you probably just need to blow some clogs out and that should get ink flowing again.
 
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