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Mimaki JV33 head starving problem with bulk system ....

rexsee

New Member
yesterday i experienced another problem quite similar, i was printing image in green when suddenly it stopped dropping yellow, so you could guess its already blue when it prints. however when i check the dampers it is still ok, half filled and not empty like before, did try to fill heads twice , still no yellow on test draw still, then performed nozzle wash, after that yellow came printing, but i can't do this always, too costly to be throwing away inks.
 

rofo

New Member
What´s strange for me is that the ink level is the same for all cartrdiges, so the pressure should be the same or let´s say very similar on all dampers. From the beginning of this week the problem never appears on both black channels. Most sensitive is the yellow channel, but one channel had about 8 dropouts the second one only two. One cyan channel 3 dropouts second one no one .... The last thing remaing on the ink way to head which can cause the problem is the damper I think. I don´t see any other reason for that. Tomorrow I am gonna to exchange first dampers on the most sensitive channels for the dropout and we will see ..... And once again Mutoh VJ running the same ink with the same head working without any dropout for months ... The only one difference is the ink system type so it supposed to be somewhere on the way of ink leading to the head ...
 

rexsee

New Member
artbot, can I ask how do you clean clogged heads using strings? do you do it going up to the ink supply stream from the damper?
 

artbot

New Member
strings? i did jam a thin wire down the tubes from the print head side to get come gelled up uv clear out of the line. stupid me running clear in a transparent tube... you can get about five feet of wire down the tube. it'd go further but it gets stuck a the big bend to go under the hull, exiting the flex chain thing.

as far as flusing, you can get the most force jetting solvent into the carts from the lines (disconnected from the dampers). also, remember as far a cleaning out the lines, go ahead and use straight MEK. it's just tubing and a refillable cart between. get the MEK in there and let it sit a minute and then blast it through to get some current flowing. you'll here a rush of bubbles when each pass is complete.
 

rofo

New Member
Hmm, maybe a good idea. Regarding my last idea, on Friday I have replaced two dampers on the most problematic channels anyway situation is still the same ....
 

rexsee

New Member
ok this is really frustrating, last week we had the whole printer replaced, with the old bulk system retained, after a few long prints we had another drop outs, the dampers were not starving but rather the head is not dropping any ink, it needs nozzle wash, it already happened twice in two days, after that they replaced the whole bulk system so essentially they replaced the whole printer except for the stand. but then next morning we had another drop out, and another the next day, and another the next day, the tech is out of options, same as me..
 

Jack Knight1979

New Member
Quickest fix is installing sealed or oem cart in the affected channel. I've been having the same issues this week. Dropped in compatible carts and the drop out vanished.

Bump up your cleaning cycles too. This is the problem with bulk systems.
 

rexsee

New Member
what do you mean bump up cleaning cycles? cleaning does not do the job, because after cleaning the head still does not print right, but nozzle wash did.

Ok, before we directly put the bulk system to the head, it was used to be installed in the cartridges, and drop outs occured, but didnt change after we change it to directly run in the bulk.. hmmm.....
 

rofo

New Member
Still the same story as we also have ... Damper replacement what I´ve focused to is also without any possitive result. The most sensitive remains yellow channel for us, the black channel is without any dropout for two weeks. There is nothing more we can try than switch back to OEM cartridges, but this is the solution which we don´t want to do ....
 

signmancanada

New Member
We've been running a Toucan LT on bulk ink for about five years now. It was a huge mistake for us due to the fact that it was also our first printer. I don't know about you folks but we are signmakers, not printer techs. We have now put on line a JV33 and we intend to keep it on OEM cartridges. While it seems like a great way to save money (the reason we bought the bulk machine in the first place) the challenges we've had, the problems we've incurred, and the material lost over the years can never be outweighed with the meager savings. I say go make signs instead of constantly fussing with a finicky and troublesome printer!
 

COREYAARON

New Member
Okay, here is what you do. First if you are not in permanent "service mode" then power off your printer. Press func/remote keys and reboot. Under Parameters change the support value to 2. It is the first screen you see after the reboot. It will let you permanently access #test, #adjust and #parameters. Secondly, the dampers for the dx5 head are 1 way dampers meaning they have a pressure valve inside that opens only due to vacuum. If you have dropout mid print then maybe your dampers on the ends....magenta.....(notoriously known for dropout and loss of vacuum for a number of reasons)....are not full. By full i mean at least half full consistently. If i were there here is what i would do and i've trained with the Mimaki engineers..ya know the 5 foot japanese guys in purple and orange 1 piece jumpsuits with matching hats...yeah, those guys....I would first go to func.-maint-st.maint-carriage out. This will move your head carriage to the platen. Immediately go to the back of the printer and turn the MAIN power switch off. Please unplug the printer also. Now you can manually move the carriage all the way to the "maintenance bay" to the far left. Notice there are 2 easily removable white screws that hold the outer panel on. Look closely at the bottom of your printhead and see if there is any ink buildup. If so take a swab or lint free cloth and wet it with solvent cleaner. Be sure to clean around the head and head fastening metal clip without actually touching the head bottom where the nozzles are. Second, unscrew the head cover plate with the 2 screws, it hides the head and dampers. Gently wiggle the 2 magenta dampers and remove them, be sure not to press on the round resevoir at the bottom bc this is where the ink is held. Hold the damper up and press on the round part. If it fills more then the damper/ink line is doing its job. This is called the "free flow test". Ensure the damper is full then mount it back on the heads nipple. Push the head back to the home capping position and reboot. Run a few cleanings and see what happens. You could also use func-#test-chk pattern-100%....this lets you now decide what res, pass and color to specify to see how quick it drops out. ALSO, you can func-setup-whatever type you are running, ....probably 1, refresh rate...change to 3 and turn on automated cleanings. good luck
 

DOmas

New Member
Does anyone have a solution how to print with jv33 with bulk system without a problem of some colors dropout?
 

Jason_Elliott

New Member
Bulk ink systems that are open air systems are fed from gravity like what Artbot was speaking of. Serious thinking of cartridge placement in height is very important and can make huge changes, so be very careful about what you do and how much you change it.

I have the ink starvation issue only with my magenta channel on the left side. I think having the bulk ink system is a waste of time and should be a sealed system. I just cleaned my ink lines out on the magenta channel both lines with the cleaning carts and a syringe. I printed the remaining days of last week and had no issues at all. If there is a chunk of junk in the line its going to make big issues off and on until its cleaned out.

The ink lines on a ValueJet are bigger than the ink lines on the mimakis. Thats why their systems being the same (cap & head) work better. But then again they are sealed ink systems. I hate my bulk ink system, nothing but problems.
 

artbot

New Member
i really don't think refillable carts count as "bulk" ink systems. they are just carts in the same height and position as the oem cart. any time you mess with the original position designed by the engineers you are rolling the dice. the ink systems in these printers is very highly balance. so that the ink travels (by weight) ever so slightly down hill. alter that weight and or positive pressure in the line and you have issues.

i've had refillable carts on my jv3 160sp with no issue at all. except for the ink is practically free (triangle, much preferred over ss2).
 

Atari

New Member
and you've adjusted the height of the ink supply. i've got my white cartridges mounted outside the machine and just raising them a 1/2" drastically affects the siphon. you can starve them or have them sweating white ink with minute adjustments.

remember that these inks are not under vacuum inside the lines. when you put your finger on top of a straw and pull fluid, the fluid is not under vacuum but it is held there by the positive fluid tension pressing against the inside of the straw not allowing the air to displace. the printer is just like that straw, your ink lines are that straw laying on its side. the way for the ink to escape is at the print head, thus raising the supply raises the fluid pressure inside the lines increasing it's ability to fall out. think of it as a chain sitting on the edge of a roof with a few feet dangling. and raising the cartridges is like increasing the incline of the roof making it easier for the dangling end to pull the remaining chain off the roof.

so concaved dampers are not good. it says that there is a resistant force pulling at the other end of the ink supply. the "chain" is nailed to the roof at the supply end.


Very good post. I think that might be part of the problem I'm experiencing with my bulk ink system and "concave" dampers.
 
Very good post. I think that might be part of the problem I'm experiencing with my bulk ink system and "concave" dampers.

In my experience servicing JV33/CJV/JV5 machines a frequent cause of dropout is the solenoid valves on the back of the cartridges failing to open fully. On many occasions I've been able to rectify this by putting a small e-clip bewteen the actuator arm and the plunger on the cartridge valve to get plunger to pull a little further when the solenoid operates. My belief is that the internal o-rings in the valve swell over time and this causes less ink to flow through the valve.

Artbot is 100% correct about the delicate balances needed when setting up a machine like a JV3 for bulk ink but the 33 is actually and excellent candidate for a tank-based bulk system; rather that the ink being siphoned to the heads it actually flows very readilly to the dampers under gravity (due to the large height differential between head and cartridges) - it's the vavle inside the damper that regulates the flow of ink to the head so having tanks slighty too high, too low, or over-filled has a neglidgeable effect.

The best bulk systems I've seen on JV33/CJV/JV5 eliminate the cartridge bays and valves entirely and just plumb directly into the ink lines. Remember that the only purpose of the cartridge valves is to allow you to switch cartridges without stopping printing - they are not needed if running a true bulk system.

One word of warning though - Mimaki machines with DX5 Heads to not allow individual alignment of the 8 color channels. The hardwired alignment works great with ES3 and SS21 inks but if you find that you have a misalignment between colors with your bulk ink there is really nothing that can be done to fix this short of switching back to the OEM inks. Triangle inks seem to produce a pretty tight alignment compared to some others I've seen.
 
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