Problem with "black streaks" on vinyl material

[SickPrints]

We use a Mimaki CJV150-130, and are having issues with black streaks. As far as I can tell, this is only a problem on vinyl material. I've attached an image showing this with vinyl material on the left, and photo paper on the right. We've tried vinyl material from 3 different suppliers and many different finishes, and the problem persists. This has only started happening in the past couple weeks, and I can't think of any changes we've made to parts or the printing process to cause this issue. The other attached image is a test print on the same vinyl material.

The print head is fairly new, and it's been cleaned well. We've tried replacing the wipers and cap pad, adjusting the heat temps, adjusting the print head height, as well as a myriad of adjustments within Rasterlink 6 Plus and the print files themselves (CMYK values, rasterizing, etc.)

If anyone has any ideas or suggestions, I'm open to anything. If more pictures or examples are needed just let me know.

 

[Solventinkjet]

Do you change color profiles when switching media or use the same one for all? If you do change the profile, try the paper profile on the vinyl and see what happens. Profiles will sometimes use variable dot sizes or fixed dot. Heads can fail in one mode and not the other some times which makes issues only show up on certain profiles. I don't see any cross contamination in your nozzle check and there aren't any deflecting nozzles which would have been my first thought. But since it's only happening on certain materials, that's what made me think of the profile issue.

To me it looks like one or two black nozzles are partially clogged so the pressure builds up and the ink shoots out longer than it should. Usually you will see deflecting nozzles if that's the case though which I don't. It still could be the issue and just not deflecting. In that case I would just do a long head soak and then cleaning to try and free up the nozzle more.

Also, just check the bottom of the head for any inkcicles hanging down

 

[unclebun]

That looks like static overspray on the vinyl, which is more likely to develop static electricity. You need to use a humidifier to raise humidity above 40% to fix that. You can test for that by using sticks in the sensors to be able to run the printer with the lid open. If the overspray goes away, that's your answer.

 

[White Haus]

Bump humidity as already suggested, probably overspray caused by static.

 

[SightLine]

With the even spacing I almost want to think you might have a bit of fuzz stuck on the print head carriage somewhere maybe stuck to the bottom edge of the media strike sensor thing on the right edge of the carriage or underneath somewhere.

 

[unclebun]

Fuzz would do the same on paper. And it usually makes droplets, not fading spray.

 

[Notarealsignguy]

Fuzz would do the same on paper. And it usually makes droplets, not fading spray.

Not on these. There's a plastic flap that gets little bits of trash built up on it that drags back and forth across the print, no droplets, just faint lines.

 

[Gino]

Looks like your black had dribbling problems. It dribbles onto the yellow, but not the black. It also is not consistent all the way down. Sounds wonky, but could it be the encoder strip ??

 

[gnubler]

Looks like your black had dribbling problems.

There's a Harlem Globetrotters joke in there somewhere.

 

[SickPrints]

With the even spacing I almost want to think you might have a bit of fuzz stuck on the print head carriage somewhere maybe stuck to the bottom edge of the media strike sensor thing on the right edge of the carriage or underneath somewhere.

This was it! Just the tiniest bit of fuzz under the plastic flap on the right side of the carriage. Wasted a week studying the head when the little flap was right in front of my eyes the whole time. Bought some humidifiers for good measure as well. Thank you all for the replies!
(Still curious why it only affected my vinyl material. If anyone's got any guesses let me know!)

 

[SightLine]

Only thinking I have why it only did it on vinyl might be how static affects the vinyl and not paper and maybe that pulls the fuzz down a bit more when printing.
Either way happy to hear it was what I figured.... I've had the identical issue on our JV150 more than once with the tiniest bit of fuzz stuck on that flap.
Happy Thanksgiving!

 

[Ogre]

I had a similar issue with my CJV150 and I found it was a ball of dust and fibres formed under the media jam sensor. This ball of fibres travelled over the capping station and getting ink from there creating black streaks identical with yours.

 

[Terrance the Deuce]

This was it! Just the tiniest bit of fuzz under the plastic flap on the right side of the carriage. Wasted a week studying the head when the little flap was right in front of my eyes the whole time. Bought some humidifiers for good measure as well. Thank you all for the replies!
(Still curious why it only affected my vinyl material. If anyone's got any guesses let me know!)

Is the vinyl thicker than the paper? Does it raise up at all when printing? Is the head height different? If none of these, probably static.