Ink pooling on printhead - UCJV300-160

[2fatdotco]

I've been trying for a while to get an older UCJV300-160 up and running again. My current problem is ink pooling on the underside of the left printhead ( stage right ). I'll call it HEAD 1.

So far, I've replaced the following:

1. All the ink lines / tubes ( MP-M018909 )
2. Cap bases ( MP-M020220 )
3. Two of the eight tank assemblies ( MP-M018701 )
4. Eight brand new bottles of Mimaki LUS-170 ink ( dual CMYK )
5. Two new subtanks ( MP-M020235 )
6. Selective path pump assembly ( MP-M018988 )
7. 2-way / 3-way solenoid Valve ( MP-E300918 )

The new test prints show a few nozzles not firing and a little yellow / black mixing on HEAD 2. Otherwise, the test prints are fine.

The problem is that HEAD 1 starts to pool ink as I run cleanings. The more cleanings I run, the bigger the pool gets. Eventually it gets smeared across the paper and makes a huge mess. I feel like I've replaced all the parts that might be causing this. Does anyone have any ideas as to what might be happening? Any chance it could be wiper or vacuum related? The negative pressure readings are all in range.

I've included images of the underside of the carriage. printhead-3.jpeg was taken after a manual cleaning of both heads. printhead-1.jpeg was taken after 2 ultra cleanings on both heads. Notice there there is a little yellow on HEAD 2 but it's mostly on HEAD 1. printhead-2.jpeg shows the error I get when I try and select only one printhead for a cleaning. It is as if I selected none at all. I don't really think this is relevant but I'm annoyed by it and curious if this is expected behavior.

You can get a little more backstory on the printer at https://www.signs101.com/threads/errors-on-ucjv300-160-61b-supply-ink-and-61d.175547/

I've spent about $3k so far and I'm getting ready to set the thing on fire. Any ideas would be greatly appreciated!

 

[Smoke_Jaguar]

Check your wiper gap and see if it is right. Also make sure your capping stations are draining right. The 90D message usually means the printer is flagged as a single head UCJV150, however, there is a bug where 90d occurs when trying to clean one head at a time on the maintenance menu. My printer has this bug, no idea how to fix, even with latest firmware. Check over your heads to see if the subtank air lines (clear ones) have ink in them.

Clean your capping stations well, and using a lint free cloth, gently wipe the heads down. Sometimes UV inks get a bit sticky and the wiper isn't up to the task, especially if it sat for a while.

If you need assistance, feel free to PM me, done a lot of rebuilds and such on these.

If you wish to set it on fire, remove the ink first as it produces some hellacious fumes when burning. Make sure to get a burn permit if in the city limits and check local fire conditions beforehand.

 

[Solventinkjet]

however, there is a bug where 90d occurs when trying to clean one head at a time on the maintenance menu. My printer has this bug, no idea how to fix, even with latest firmware.

Check system parameter 66. It should be set to "2" If not, the machine will think it's a 1 head or 0 head machine.


Also, make sure your pressure settings are within spec and do an air purge. That can take care of issues like this.

 

[Smoke_Jaguar]

Yup, firmware bug with the 90d error is something I see more and more of. No real good way to fix it if it's not that parameter. Head will still read, print, etc. Just comes up when doing a head select cleaning in the case of the bug. Annoying, since you cannot clean just 1 head.

 

[2fatdotco]

Check system parameter 66. It should be set to "2" If not, the machine will think it's a 1 head or 0 head machine.


Also, make sure your pressure settings are within spec and do an air purge. That can take care of issues like this.

Interesting. I didn't know that could be done. Is it possible that a firmware upgrade might have changed this setting without me knowing it? I'm certain I didn't manually change this.

On a related note, can these settings be used to run the machine with only one printhead, just in case I actually do have a bad one? Thanks.

 

[2fatdotco]

Check your wiper gap and see if it is right. Also make sure your capping stations are draining right. The 90D message usually means the printer is flagged as a single head UCJV150, however, there is a bug where 90d occurs when trying to clean one head at a time on the maintenance menu. My printer has this bug, no idea how to fix, even with latest firmware. Check over your heads to see if the subtank air lines (clear ones) have ink in them.

Clean your capping stations well, and using a lint free cloth, gently wipe the heads down. Sometimes UV inks get a bit sticky and the wiper isn't up to the task, especially if it sat for a while.

If you need assistance, feel free to PM me, done a lot of rebuilds and such on these.

If you wish to set it on fire, remove the ink first as it produces some hellacious fumes when burning. Make sure to get a burn permit if in the city limits and check local fire conditions beforehand.

Thanks for the reply! Well, the caps have been replaced and I've cleaned the heads thoroughly. The ink just keeps coming back on Head 1 . Are the photos useful at all? The one named printhead-1.jpeg was taken after a few ultra cleanings. I ran the cleanings then put it into station maintenance for the heads. Shouldn't the wipers have cleaned the surface of the heads as the carriage was leaving the capping station on it's way to the other end of the printer?

Any ideas how I can fully test the wipers? Thanks!

Also, don't worry. I won't burn it. I'd first send it to your shop so you can strip it for parts

 

[Smoke_Jaguar]

When's the last time the subtank was replaced? If flushing the head manually, it tends to destroy those and cause ink issues like that. Also, yes, as Solventinkjet said, do a vacuum/pressure test.

As for stripping down a UCJV300, never had to do that, always get them running.

 

[2fatdotco]

When's the last time the subtank was replaced? If flushing the head manually, it tends to destroy those and cause ink issues like that. Also, yes, as Solventinkjet said, do a vacuum/pressure test.

As for stripping down a UCJV300, never had to do that, always get them running.

Both subtanks were just replaced last week so I'm doubtful they're the culprit. I'll run another vacuum/pressure test and get back to yall.

 

[Smoke_Jaguar]

Check the clips, make sure they are snug and 2 clicks when they lock.

 

[2fatdotco]

I did the following things today:

1. I checked system parameter 66. It was set to "2" so the 90D error is just the firmware bug described by Smoke_Jaguar.

2. I ran a pressure test. Both negative and positive pressures are within range. No beeps.

3. I verified that the pump is draining properly. First I did a disway wash to make sure the cleaning solution disappears from the caps. Then I pulled the line out of the waste tank, ran another wash as well as a few cleanings and verified that ink and cleaning solution are coming out of the waste tube and into the waste tank.

4. I reseated the cap on head 1 then did an adjustment of the caps.

5. I verified that there is no ink in the subtank air lines. They are completely clear.

The next thing I'm going to do is swap the position of the heads. I'll put Head 1 in Head 2's place and vice versa. If the problem ink pooling problem persists on Head 1 when it's in the Head 2 position, it's probably a bad head. If the problem stays on the same side of the carriage, it's something else. Although what that something else could be, I still don't know. I feel like I'm running out of ideas.

Enclosed is a photo of the carriage, as it stands now. Notice it's missing an air purge plug. Mimaki says that shouldn't matter. Do yall agree?

 

[Smoke_Jaguar]

Head juggling will mean loss of alignment and tedious calibration process. Likely air getting into subtank, check all fittings and clean the underside of the print carriage. Inspect for signs of leakage. Also might be a good idea to empty waste tank and see how much pools in it overnight.

 

[2fatdotco]

Head juggling will mean loss of alignment and tedious calibration process. Likely air getting into subtank, check all fittings and clean the underside of the print carriage.

By " Likely air getting into subtank... " , do you mean that if I juggle the heads, I risk getting air into the subtanks? Or do you mean that currently, it's likely that I'm getting air in the subtanks? Thanks.

 

[Smoke_Jaguar]

The subtanks, when full of ink are very easy to destroy. Above each ink chamber is a filter pad that, if ink gets on it, will soak it up and stop letting air flow to the tank on that channel. Air is important as the vacuum/pressure assists with ink filling, cleaning, etc.

As for moving heads around, it will just cause a lot of grief doing calibrations. I do a lot of free tech support on UCJV300s, but when someone decides to move heads around, I just shrug and say 'have fun' as there's little way to be of good help on calibrations without burning hours.

If a subtank has a crack, leak, a line isn't fully connected or the tank isn't seated fully, it can cause the issues you're having.