Mutoh maintenance station / Cap top?

[Rat_Fink]

Hello.
I have a Mutoh ValueJet 1204 that is used almost always on a daily basis (aside from weekends).

Last week I was printing a bunch of logos and noticed that the black areas appeared to be a bit washed out looking.
After a nozzle check, it appeared that approx 50% of black was blocked.

I was thinking I was in for a new print head & then I let it soak in cleaner for about 30 minutes, ran through some cleaning cycles, did another check and I had it almost to 100% clear.
Printed a bunch more logos with perfect results so thought I was good to go.

It sat over the weekend & this morning it went through a cleaning cycle and I printed a 4'x6' full color and all the black seemed a bit washed out.
So I am back where I started from last week. Since I was able to get the nozzles clear, would it be best to assume that I am looking at a maintenance station?
Or should I first try the cap top?

Thanks for any info!

 

[Solventinkjet]

How old is your maintenance station? Usually I will start with a new cap top rather than replacing the whole maintenance station becuase it is cheaper and normally does the trick. If the maintenance station is older than one year I would just replace the cap top. If it has never been changed in 2 or more years, I would test it for clogs and think about replacing the whole station. In your case, since the problem seems to be isolated to the black only, I would also change the dampers and o-rings.

 

[Rat_Fink]

Not sure of exact age, but I know it is over 2 years old. Is there a guide that shows how to test for clogs and how to check the seal of the cap top?
Thanks for the response!

 

[Stealth Ryder]

You need a new Maintenance Assy

You need a new Maintenance Assy...

 

[RG]

Not sure of exact age, but I know it is over 2 years old. Is there a guide that shows how to test for clogs and how to check the seal of the cap top?
Thanks for the response!

I'm no expert, but I also have a 1204. How to test visually for clogs: remove the right side cover; do a head cleaning and watch carefully the 2 tubes under the cap top to see if ink passes through both tubes. If you are not sure, then remove the fixture that holds the cap top. There are just 2 screws that hold the fixture in place. You will have to disconnect the 2 black tubes that go from the cap top into the pump. Now, use a syringe with a piece of tubing and try to push some cleaning fluid into both tubes that go into the pump. If the pump is not clogged, then it should be easy to push the cleaning fluid. If it is clogged and you can not push any fluid trough, then use another syringe and connect it to the tube at the bottom of the pump (this tube goes into the wast ink tray) and pull with that syringe while you are pushing with the other syringe. That has worked for me before. If all that seems like too much trouble, then get a new pump or new maintenance station. If the pump wasn't clogged, then do as someone suggested earlier, and replace the black dampers & o-rings. If you use the OEM dampers that you find on ebay for about $3.00 each, then I'd replace all the dampers & o-rings. Of course, if you feel better using the $65.00 each OEM dampers from Mutoh, that's another option. Good luck!

 

[TDFcustomSL]

My machine was right at a year old when I started having issues. Noticed when I did a cleaning no ink was flowing from the 2 tubes into the waste tray. Took a gamble and ordered a capping station off ebay from china and had it in 6 days. It cost me $17 but fixed the problem right away. I ended up learning that my old capping station was probably just fine but the tubes going to the waste ink tray were both clogged. You could check to make sure the tubes aren't clogged first but I would still start with a capping station before I replaced the whole assembly.

 

[MagnetStew]

I have found that most maintenance stations last a very long time if you replace the cap every so often and clean the tubes about every six months. To clean the tubes just pour the cleaning solution of your choice (not alcohol - makes most eco's clump up) into the cap until it looks like its going to overflow. After a few seconds gravity will do its job and the fluid will start to make its way through the tubing. Do this for a while and put a bowl at the tube outlet. After a bit you will see all sorts of gunk makes it way through the tubes.

 

[Rat_Fink]

Thanks guys - I'll check out these tips.
Any online resources for a service manual so I can read up on the instructions?
Thanks again!

 

[Rat_Fink]

Update - Changed the Maint Assembly

I changed the maintenance assembly. I also did a head soak in the cleaning solution.
I was able to free up almost 100 % of the black nozzles. Completed a few large prints with success.

Now - I'm back to where I started. Blacks are looking washed out & a nozzle test shows most all of the black is blocked.

 

[Solventinkjet]

It sounds like you may have ink flow issues. Is there air in your ink line? The dampers should be about half full and the ink line should be perfectly solid black.

 

[Rat_Fink]

The ink lines seem to be solid black. the dampers (on all colors) seem to be 100% full.

 

[Solventinkjet]

Full dampers is usually a sign that the maintenance station was bad but it doesn't necessarily mean it would cause your issue after the maintenance station is changed. Make sure ink is actually coming out of the waste tubes when you run a cleaning. It's pretty rare but sometimes the cap will not line up with the head after the maintenance station is replaced. Check the bottom of the head for anything that may be breaking the seal with the cap top as well and clean if necessary.

Double check that the wiper is not really dirty as well as it may be pushing dry ink into the head nozzles. Since black is the first channel next to the wiper, it is usually affected the most by a dirty wiper.

Sometimes ink cartridges do not flag the machine properly when they are empty and that can cause your issue. Take the cartridge out and shake it. You should feel ink moving, if not, that's your problem.

If everything is clean, ink is flowing properly through the maintenance station, the cartridge is full, and you aren't getting sub tank errors, change the dampers (I recommend changing them anyway if they are over a year old). If that doesn't do the trick, I have seen heads fail in this way although it is very rare.

Edit: There are no sub tanks on a 1204. Disregard.

 

[Rat_Fink]

Thanks for the reply. I removed the waste ink tray & placed a rag under the maint station.
I used a screwdriver to hold the waste tray switch and ran a strong cleaning cycle.
Plenty of ink was discharged under the maint station.
Wiper is clean. All colors are 100% in nozzle check except black.
When doing a nozzle check, The block nearest the maint station is fine, but the next block of black is almost all gone.

 

[Rat_Fink]

Not sure if this makes a difference, but this is not happening from just sitting overnight.

For instance - today - I printed a sheet of 60 small bumper stickers with a black background.
the 1st sheet printed fine - black was black.
I printed the second sheet like 5 minutes later and the black looked more like a charcoal gray.
running a couple of cleaning cycles actually made the nozzle check worse.

 

[Rat_Fink]

Also - the printer is telling me my black ink cart is almost empty, yet I can still feel ink sloshing around in it.
It's not new, but definitely not empty.
A brand new cart weighs 12 7/8 oz on my digital scale.
The one in the printer weighs 8 1/2 oz.

 

[Rat_Fink]

Update

I changed the main station and it seems to be sealing well - I can kook a syringe underneath and it will draw ink out, but with plenty of resistance.

That did not fix the problem so I also changed the dampers. One of the dampers did not want to fill. I had to remove the damper and draw the ink from the line where it connects. I still think I am having problems with ink flow from that line.

I ran several cleanings and sometime is shows hardly any black nozzles and at other times it shows them back again..

At one time - I had my nozzle check to almost 100%, but then it dropped out again..

Since the nozzle check sometimes shows good - is it possible that it is a bad head? Seems to me that if it were bad, it would consistently show bad nozzle checks.

Any help would be appreciated. I'm at my wits end with this.
It was working flawlessly a couple weeks ago.

 

[mnapuran]

Best source for the maintenance station? I've got a 1304 and I think it's past time

 

[Solventinkjet]

Best source for the maintenance station? I've got a 1304 and I think it's past time

Feel free to give us a call: 303-733-6671. We have OEM maintenance stations and other options, that we can explain to you over the phone, to save you money.

 

[alexcim]

Rat_Fink, any updates here on what you did to resolve the issue.

I basically have the same issue with a VJ-2638 where doing a clean ruins the black channel (introduces air into it, so half or more of the nozzle drop out)

Many cleans struggle to resolve it, often I need to resort to a little charge.