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JV 33 printhead began printing wrong color

Discussion in 'Digital Printing' started by Team One Displays, Sep 9, 2011.

  1. Team One Displays

    Team One Displays Member

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    Jul 26, 2010
    I'm searching throught the past forums for answers but wanted to see if anyone has suggestions in the meantime. MYJV 33 printhead began printing the wrong color on one channel. In the middle of printing - it looked liek yellow had dropped out. I stopped the pring and did a test draw - all nozzels fires except one of my yellow blocks is cyan now.

    Ink is full - I've cleaned everything and performed multiple nozzle washes and the usual. No luck. I can get maybe 1/2 to turn yellow but they quickly go back cyan.

    Any ideas?
     
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  2. SightLine

    SightLine Very Active Member

    my guess is you might need a new cap top for your capping station. Sounds like it has a leak. Since all heads are on the same top - a leak can cause whichever head has the least pressure in it at the time to draw a tiny bit of ink from the other heads up into it some along with other odd things like just one set of nozzles dropping out etc. I'd clean the bottom edges of the head and the capping rubber really well and maybe do a 1 hour nozzle soak. Might have to print a foot of solid yellow to clear it back up afterwards. I've seen the same on ours and it clears up.

    Regardless - as long you are not seeing some other color backing all the way up into the damper (should not be possible due to the one way valve in the damper and valves at the cartridges anyways) then its going to clear after a bit of printing on that channel.
     
  3. Team One Displays

    Team One Displays Member

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    Jul 26, 2010
    I let ran a nozzle soak for 4 hours - still no yellow. I replaced the capping station a couple of months ago so it's pretty new, and I just replaced the yellow damper last night to see if that took care of the problem. Before I pulle the old damper I could see the tiniest bit of green inside the yellow damper. After I replaced the damper half of that channel printed yellow for a couple of test prints while the other half remained blue. Now all I am getting is 100& cyan firing from the yellow channel when I perform a test print.

    In the pic - the pen marks where I should be seeing yellow. It's printng as if it is a cyan channel.

    It looks as if the problem is below the dampers. Mimaki says someone had to put the wrong color cartridge in the yellow slot but I can't see how that would be - if someone inserted the wrong cartridge I would see some shade of green firing in the test print - not 100% cyan. I've checked the lines anyway when I changed the damper.

    I'm at a loss - can the contamination be coming from inside the head assembly (below the damper) and what could cause this?
     

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  4. SightLine

    SightLine Very Active Member

    In that case I might wonder if the head manifold has internally broken down allowing ink to cross between the 2 channels or possibly the head itself.

    Wrong ink (cartridge might be marked yellow but has a cyan bag of ink in it) could be the culprit but then both yellow channels woudl be affected. Cannot say I've ever run across that though. Regardless though - both yellow channels are feeding from the same cartridge which rules that out anyways.
     
  5. Team One Displays

    Team One Displays Member

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    Jul 26, 2010
    Thanks for the tips - of course it happened at the worst time possible. I'll keep trying!
     
  6. SightLine

    SightLine Very Active Member

    I hear ya.... it's much like dropping a screw beside a vehicle/trailer. There is an unseen force/rule that requires the screw to bunce 3 feet sideways and come to a rest as close to center underneath the vehicle as possible.

    Anyways good luck - hope it's not the head.

     
  7. Robert M

    Robert M Very Active Member

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    Jan 23, 2007
    colorado
    Jv33

    I didn't read down all the suggestions, so if someone touched on this ok. We just had that same issue with a JV33. It turned out the valve on the yellow ink line failed to open. They can be checked in the service menu. if the yellow channel is dry you may be pulling another color or colors during the soaking and cleaning into that channel.

    PM me for more onfo
     
  8. Team One Displays

    Team One Displays Member

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    Jul 26, 2010
    It turns out the head was shot. Using a syringe a purged cleaning solution through the yellow damper and into the head - being careful not to apply to much pressure. The fluid never cleared up it just kept leaking cyan. The baffle, or gasket between the cyan channel and yellow channel in the head was broken.

    Luckily Mimaki's office is close to our shop. I just finished replacing the head and recalibrating the machine. Finally - it's printing again.
     
  9. SightLine

    SightLine Very Active Member

    Ouch - that was an expensive issue! Especially getting the head direct from Mimaki. Glad to hear you figured it out and are back up and running though. These JV33's are great machines - love ours.
     
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