JV33 Head dropouts help!

[MonoJoker]

Hi All,

I'm hoping somebody can help me as I'm at my wit's end with this. More or less since we got the machine and replaced the printhead this issue happens intermittently - one or more of the colours (most often red) drops out suddenly - usually during a print and then no matter how many fill up inks, head cleans, etc it doesn't fix the problem. In fact usually it gets worse - say one magenta drops out then you do a head clean after which a blue will drop out too. It's then a matter of luck as to how many head cleans, fill ups, etc until it works again but more often than not it then does this again. Last time when it simply wouldn't come back from this we replaced all the dampers ensured no air was in lines, etc. Then it printed for weeks without problem. You'd come in for the day, fire it up, head clean, print and print no problems. Suddenly 2 days ago out it drops and again it's taken 2 days and nothing will fix it. I'm honestly going to take to it with a hammer soon as this is costing us more money than the thing is even worth in hassles...

So today I replaced the M6 valves on the back of machine as I'd been told by a tech those often fail and cause such dropouts. The end red valve was rusty and the spring fell out in 3 places so I thought that might be the issue as red is the most common colour to drop out. It was more than frustrating to find after doing that the issue not only remains but is worse. I watched the ink lines fill up fine after changing valves as the lines were clear from having them disconnected. At the moment I have one red missing, one black gone, half another black gone, yellow printing about 25% and blue not much better. This is all after many fillups, etc.

The dampers on some colours appear to not be filling up and I have no idea why.

WTF is the issue here it seems to have been inherent since day 1 but so random that it'll print for MONTHS ok then suddenly pull this sh** when I have jobs to print...

Sorry for the rant and I'm sure the only fix is to pull EVERYTHING apart and start from square one which I just don't have the time or patience to do. Hoping for a miracle from someone who's had a similar issue and managed to fix it somehow.'

Prepared to sell soul to devil, buy live chicken for voodoo sacrifice, etc just tell me what I have to do!!!

Thanks for listening

 

[SightLine]

It sounds like you have already replaced most everything. A couple of other bits though. The joint valves that sit on top of the dampers (and possibly the O-rings on their fittings). These pieces are actually valves - its must be fully on the damper before ink will flow. I've had one of the fittings on the top of one of the joint valves just get a bit loose once before. Took me a week to finally figure that one out. I've also had defective aftermarket dampers before. That one took a few weeks to troubleshoot since it was just the tiniest leak that was at the very bottom of the damper where it sits on the head manifold. It had ink in it but when the head would be over the cap top and the pump going it would suck air into the head. Bad seal on the capping top could be a spot - that can often cause a dropout on a single channel. The spring under the cap top can also weaken some over time. Clogged or failing pump is another to check. I've never had good luck with aftermarket pumps. If its not been replaced, always spend the extra and get an original OEM Mimaki pump, it will last several years with no issues.

Aftermarket parts, while very lucrative due to their low cost can be hit and miss on quality. I've had bad aftermarket pumps (several), dampers, capping tops, and even a bad aftermarket head manifold. All "looked" okay and seemed to work but continual problems eventually led me to find a tiny leak or some other defect. I'm sure that sometimes even new original OEM Mimaki parts can be bad too. I still will use aftermarket parts for some things though, just if I have an issue I know to scrutinize them. 3 parts I will never use aftermarket again, pump, capping top, dampers. The time I spent troubleshooting them was by far cost me much more than any savings I had by going with cheap aftermarket ones. Even when they do work, they do not seem to last nearly as long as original OEM parts.

Other things like tubing, O-rings, wipers, and a few other bits, sure I will still use generic stuff for. Just too many times that aftermarket stuff has bit me in the as$......

 

[Solventinkjet]

A common problem I see on these machines is that the cap slider wears out and makes it so the cap top doesn't line up anymore. Magenta is the color most affected becuase it is on the edge of the print head. The good news is that it is cheap and easy to install! Here is is on our website Cap slider. I am willing to bet that is the problem. I have run into this exact issue many times.

 

[bawraps]

Same problem

I'm having this issue too!! I have been having issues since last Monday. I got a new pump over the weekend and put it in this Monday because it was suggested that I do so. I ran test prints, my prints were pretty much back to normal (just a couple nozzles missing) Monday night. Then I come back in Tuesday and almost all of the heads are down. All I have is both blacks (with more missing nozzles than before) and the right yellow. I cannot get them to come back. I am freaking out!! I replaced the cap as well (one from solventinkjet.com) and it did nothing. I'm thinking about putting the old pump back on to see if I just got a bad pump. I don't know what else to do.

**Edit** I opened the valves and attempted to draw ink through the bottom of the cap. The right side pulled ink into the syringe but not a ton. The left side didn't pull anything but air. So that means a bad cap correct? I'll put the new one from solventinkjet back on and try again. If that doesn't work, does that mean I got a bad replacement cap or something else? I am at my the end of my rope with this thing. I have jobs that have been waiting to be printed!

 

[petesign]

Could be a few issues, but most have the same actual issue.... the seal between the head and the cap. If you've loosened the head assembly to change head height, it could be uneven, if the cap looks good, it could still be worn out... etc... start there.

 

[MonoJoker]

Thanks guys, I'm ordering some genuine dampers and top clips for them now. I'll try anything at this point in time! I replaced the cap and pump within the last 3 months but both are non-genuine so, again I'll order genuine and rule everything out. I've managed to get some jobs out around dropouts but it's definitely not "right" so will replace everything as I go.

Thanks heaps guys I was really going round the bend trying to fix this

 

[MonoJoker]

Well a new cap and pump fixed for a short while but still the issue persists, now only on the leftmost red head (looking from front of machine). So I've bitten the bullet and booked a tech to come out. Might as well get to the bottom of it and watch while he fixes it so I know for next time The reason we're reluctant to get techs usually is the cost - 2 hours travel time each way plus however long onsite, etc. It soon adds up but we're wasting enough ink and material (and time!) to justify it. Thanks for the suggestions guys, I will order a new cap slider as well based on the info.