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Overspray Problems on JV-33

Discussion in 'Mimaki' started by Vinylman, Oct 5, 2012.

  1. Vinylman

    Vinylman Very Active Member

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    Aug 15, 2005
    Berlin Center, Ohio
    I am experiencing increasingly more over spray from the black channels on my JV-33 print head.

    I have lost several of the nozzles, and after numerous soaks and clean cycles, as well as drawing ink down through the docking station, the problem persists.

    Anyone have any suggestions what I can do to pinpoint the problem? Does it look like I might have to put a new head in?

    Any suggestions GREATLY appreciated.

    I used the search mode here on the forum, but could not find anything that addressed specifically how to troubleshoot over spray issues on the JV-33.
     
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  2. Masseria

    Masseria Member

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    If you are able to, attach some pictures of the problem.

    Im using Aqua based ink, so i can use only water to clean it. if you using solvent or other stuff you might want to start with cleaning solution.
    I dont know what kind of inks you are using.. but it might help.
    I've done these several times never went wrong and im using a recovered printhead with all the nozzles in perfect condition for 3 days printing 24 hours non-stop.

    1°) send cleaning solution in the upperhead color by color. so you can check if you can recover clogged/ with dirt nozzles. and also these will clean the printhead. then try the following steps at your own risks.
    Take all dampers out. and do following steps at own risk to clean / recover lost nozzles.
    1)start sending cleaning solution with low pressure (color per color in the upperhead, I mean where dampers connect with printhead)
    2)then you must do a lot of strengh to make the printhead rain (this we call it shower) looks like it. With a Flashlight you'll be able to see if you are missing any nozzles in the shower, and also you will notice if a nozzle is not firing properly(you will see that liquid its not going down straight, and it going to left or right depend on dirt/clog).


    if its not working:

    Then i'd try with another printhead (old one), and clean/leave the new printhead until no ink is on it.. for this you must do:
    Leave it in cleaning solution for 2 days.. you will notice solid ink particles that are inside the printhead that can only be removed with printhead in solution for some days...you need to wash these solution not so often but dont let the particles that came out stick to the printhead again...

    Im actually doing this and i've recovered the printhead that came with the machine when we bought it. and works perfect 100% nozzles.
    Just be sure not to touch the electronic stuff with the solution.
    We have a new printhead (that was replaced for the old one) and its floating in the solution.


    If you are taking it out and replacing it. send cleaning solution in the upperhead color by color. so you can check if you can recover clogged/ with dirt nozzles. and also these will clean the printhead.and also do it backwards. I mean absorb in the upperhead color by color this is the best way to clean a printhead from the inside... because the dirt that came with the ink the only way out is up , from where it came from.
    Nozzles are so so so so ultra super ultra tiny. so if a hair is stuck in a nozzle it wont came out through the printhead you need to doit backwards.

    hope it helps you...
     
  3. Vital Designs

    Vital Designs Vital Designs

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    Dalls, Texas
    A little more info about the type of overspray and maybe a picture would help.
    Is it an alignment issue (drop position) or an actual overspray? In my experience true significant overspray is a head issue.
     
  4. Vinylman

    Vinylman Very Active Member

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    I am using Mimaki ES3 inks. [ecosolvent] I have used ONLY Mimaki original inks since start up.
    We have tried 99 minute soaks with factory cleaning solution.

    I have followed artbots' recommendations for using slightly stronger aftermarket solvents from Sherwin Williams chemical division with limited success.

    Thanks for your replies.
     
  5. rjssigns

    rjssigns Major Contributor

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    Black printhead on our Roland is far from perfect.. When we have overspray it is either the result of static or a dirty encoder strip.
     
  6. CS-SignSupply-TT

    CS-SignSupply-TT Very Active Member

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    How long have you had your JV33? How often do you encounter this BLACK OVERSPRAY issue?
     
  7. MikeD

    MikeD Active Member

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    Did your test prints simply drop out the nozzles, or did it begin with some deflection and grow into a larger problem? One thing that came to my mind was the possibility of static being generated as material is unwound and fed into the printer. It would be even more of a possibility if your material is on a polyester liner. Usually, static is brought up as the culprit when no obvious concrete causes are seen, but, static can influence the "flight path" of the ink droplets; even to the extent that they rebound back onto the head's membrane. You can use a static meter to see if there is infact a charge, or just put your hand near the vinyl (top and bottom) as it comes off of the roll. If you find a charge, you can discharge it with tinsel, or a high-dollar deionizing air knife.
    Most likely, static is not the culprit, but it would be good to negate that argument before your tech gets the chance to blame the problem on static and leave you hanging.

    If the defect is more like a large dot rather than a misty spray, it may be that ink is not getting cleaned off of your print head, and subsequently dripping. That scenario could be caused by a damper that is going bad and not able to regulate the flow correctly, a head cap that is deteriorating or even a bad wiper.
    To check the damper's condition, take the cover off of the carriage and look on the left side of each damper as yo are facing the carriage. The round window should be flat. If it's bulged out, replace the damper.
    As for the wiper, if it is at all warped, change it. Make sure that when cleaning the wiper that the back side; under the curved lip is clean as it is the working edge that comes in contact with the head when it wipes off excess ink.
    When it comes to the cap head, make sure that there is no plasticized ink around it, and that it's not deformed. It needs a good seal in order to effectively clean the head.
    If all of those are in good order, the next thing to look at would be the pump right below it. Make sure that when the capping station gets filled with wash fluid, it stays there as opposed to quickly draining out. You can also put a volt meter on it to make sure it's getting adequate power.
    All of those parts are cheaper than a head unless you have a parts warranty.
    Wish I could be of more help, but I am only learning this as I break mine!
    Good Luck!
     
  8. CS-SignSupply-TT

    CS-SignSupply-TT Very Active Member

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    MikeD, thank you for your thoughtful and detailed response.
     
  9. Vinylman

    Vinylman Very Active Member

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    Thanks so much for your detailed response. Hopefully it will help others as well.
     
  10. Vinylman

    Vinylman Very Active Member

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    Update

    I have managed to get the Yellow, Cyan, and Magenta channels back and printing with numerous hard cleanings, and several ink draw downs with a syringe through the capping station.

    The black has come back partially, but with MANY of the nozzles still not cleared. I have injected cleaning solution down through the nipples on the manifold through the head, and gently one time drew cleaning solution up from the capping station into the print head and out through the nipple on both sides of the black channels on the head.

    Still getting lousy results on the black part of the head [stripes showing in solid areas of print probably due to head clogging].

    Does anyone have any other solutions other than replacing the print head?

    Artbot? any suggestions?

    P.S. is it safe to just open the valves for the black ink channels when doing the ink draw downs with a syringe through the capping station. Rather than opening ALL valves?

    Could this create to much vacuum pressure through the capping station because the vacuum is being concentrated into only one [or two] colors rather than across all color channels?
     
    Last edited: Oct 7, 2012
  11. Jack Knight1979

    Jack Knight1979 Very Active Member

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    I hate to say it, but that head is bad. Do an ink swap just to verify. I've been down this path many times.
     
  12. CS-SignSupply-TT

    CS-SignSupply-TT Very Active Member

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    Vinylman, what did you decide to do?
     
  13. Vinylman

    Vinylman Very Active Member

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    Yesterday I bit the bullet and swapped out the head.

    With shaky hands and serious trepidation I jumped into the head swap. 37 minutes and ink stained hands and I was back up and limping through the final ink pulls and head cleanings.

    WALA! It prints fantastic.

    I am still trying to decipher the Japanese to English translation of the manuals, so doing the alignment adjustments are at a stand still until I can get better directions on how to finalize the alignment issues.

    Any one that has CLEAR alignment instructions, I would welcome any help.
     
  14. MikeD

    MikeD Active Member

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    Yesterday I had a similar problem with a JV33. I was about to go through the basics; inspect cap head, dampers, pump... but then I saw it. The tube coming from the wash cartridge to the capping station was designed in a way that it rubs against the metal frame. Eventually it wears through. Mimaki put a tech notice out to have all units repaired with the new part, but not all of my printers got fixed. Yesterday I noticed that the tube was dripping wash from the side; right before it connects to the stainless pipe leading to the cap head. I put a new piece of tubing in there and the black defect disappeared.
    Check out the tube right before that elbow in the stainless pipe if yours was not fixed. The printer might not be getting enough fluid to clean itself.

    Just saw you replaced the head... make sure that tube referenced above is in good condition so your new head stays clean.


    Good Luck!
     
  15. Vinylman

    Vinylman Very Active Member

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    Thanks Mike I'll check that out:U Rock:
     
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