Printing Problems with Mimaki JV3 160SP

[SchultIndustries]

We've been having a number of issues with our JV3 after replacing heads. We've also replaced the pumps, dampers and capping station. We're at a loss as to what to do. When we replaced the heads it ran fine for a while but the color was off. The new yellow head ran with both sections for a while and then one half dropped out. Nozzle washes and dishways don't seem to help. I've included a photo below in hopes someone can offer advice.

 

[jfiscus]

I think the black lines are going to be where you figure out what the issue is. There are a number of things that could cause the missing yellow, but it looks like you have already addressed most of the usual suspects. I am betting on the slider board as to me it looks like a circuit board issue with the random black lines.

 

[WalkerP]

Ouch, looks like a couple different issues to me.

A few questions...
What ink and type (solvent, H2O, sub)?
Why did you change the head(s) originally?

The black lines through the print can be a few things. I'm pretty sure it's electrical. Check the ribbon cables to make sure they're seated properly, aren't scorched, etc. If they look OK, you can swap the C/K ribbon cables either on the board or on the heads. Your nozzle check and prints will look crazy, but this is for troubleshooting. If the C head streaks, it's a board upstream. If the K head continues, it's likely the K head itself. Report back after those tests.

The yellow head you can do the same thing, but just swap the left and right ribbons. If the alternate side prints, it's electrical. If the same side continues to print, it's a flow issue. You can do the same test by swapping the dampers. Just trace the symptoms and it will lead to the cause.

Let us know how these tests come out. Hopefully we can help you get it worked out.

 

[WalkerP]

Also, check the head temps in the maintenance/service menu. I can't remember the exact route to get there or what normal is, but if a head(s) is bad, the temp will be way different than the others.

 

[SchultIndustries]

Our ink is solvent.
We changed the heads originally because they were clogged and had numerous head strikes after many years of continued use.
We changed out the head ribbons recently and don't look scorched.
I'll have our guys try out suggestions and list the results. Thanks!

 

[SchultIndustries]

Here is what my guys came back with:

Yellow Head Ribbon Switch: Test draw showed NO yellow on either half

K/C Head Ribbon Switch: Please see print photo below.

 

[WalkerP]

I am leaning towards agreeing with jfiscus and the slider board. Check the head temps though.

 

[SchultIndustries]

is there a normal temp range reading that it should be?

 

[WalkerP]

Yes. I just can't remember what it is. I don't have a Mimaki anymore. Just check all of them via the service menu. If any of them are bad you'll know it. Their temps will be much much different (much higher if I remember correctly). 9/10 times when a head gets fried you can smell it. Do the smell test and see if you can smell any fried components.
I am leaning towards the board however. I'd start there. I hope Mimaki still does this, but if you buy a board, and that's not the problem you can return it for a full refund. You can check the board and see if you can find any scorches, or if EE inclined, meter it and see if you can find any blown fuses, etc.