Need Help! Ink flow slows during printing

[GatorTPK]

Hi,

I just replaced the print head and dampers on a VJ-1324. I followed the “VJ-1324 Maintenance Manual” to the letter. The first nozzle check was perfect, an awesome sight. But subsequent nozzle checks will show missing spots and the ink flow will reduce on every color during printing. I can do a “short cleaning” and get a perfect nozzle check again. But it’s only good for the first half inch of a print.

I’m using Mutoh branded Eco Solvent Ultra ink. The DX7 print head is from Mutoh as well. The ink appeared to charge quickly when refilling the link lines after the head and dampers replacement and first nozzle check is good, so I don’t suspect a problem with the maintenance station. (I do have a Lifetime Pump error though.)

I attached a photo of a test print to indicate the issue. Any suggestions would be greatly appreciated!

 

[Umca]

What dampers did you use? From Mutoh?

 

[rjssigns]

Possible air leak at the damper or capping station. Could even be a bad damper. Just because it's new doesn't mean it's good to go. Learned that lesson a long time ago.

 

[GatorTPK]

What dampers did you use? From Mutoh?

I used the dampers from DigiPrint-Supplies. This is the link of the dampers I purchased:
https://us.digiprint-supplies.com/en/mutoh-dx6-roland-dx7-valve-head-assy-damper-pdavj161401o2

 

[GatorTPK]

Possible air leak at the damper or capping station. Could even be a bad damper. Just because it's new doesn't mean it's good to go. Learned that lesson a long time ago.

Thanks for the info. I did learn that same lesson when I replaced a maintenance station and it gave me a month of grief. It was a bad maintenance station.
I purchased another maintenance station (a known good brand!) yesterday and it just arrived so I’ll be replacing that today. Hopefully that’s the cause of my ink flow issues. The old capping station may not be creating a strong enough vacuum for good ink flow for printing but good enough to fill the ink lines.

 

[Umca]

I think you have the problem because dampers not so good. If nozzle check looks good after cleaning it means maintenance station works properly. Try to install back removed OEM dampers.

 

[GatorTPK]

I think you have the problem because dampers not so good. If nozzle check looks good after cleaning it means maintenance station works properly. Try to install back removed OEM dampers.

I hadn’t thought about the dampers being an issue because I’ve always gotten good hardware from Digiprint-Supplies.

I replaced the maintenance station yesterday and I got a beautiful perfect test print. (Photo attached.)

Then this afternoon when the printer was used again for the first time since last night and it appears to be ink starving again! Where do you suggest I buy the dampers from? Do you have a link?
Thanks for your help!

 

[GatorTPK]

I think you have the problem because dampers not so good. If nozzle check looks good after cleaning it means maintenance station works properly. Try to install back removed OEM dampers.

Thanks for the info. I looked for new dampers and found some from the same company at about 10x the price. They appear to be OEM Mutoh. I wished those showed first when I searched for new replacement dampers. This is what I just purchased:
https://us.digiprint-supplies.com/en/vj-1614-valve-head-assy-damper-dg-41543-pdavj161401

 

[Umca]

The maintenance station is need for get ink flow throught printhead. For refill printhead by ink. It does not use while printing. Pump in maintenace station can make a high pressue for get ink flow. But springs in valves of the dampers may be stronger (case 1). Or may be valves not close completely (case2).
Start the print. When the colors starts missing open front cover for make a pause and check the printhead surface. If no drops on printhead - case 1, If you will see drops - case 2.
Also check blocking valves in ink lines between cartidges and printhead.

 

[GatorTPK]

The maintenance station is need for get ink flow throught printhead. For refill printhead by ink. It does not use while printing. Pump in maintenace station can make a high pressue for get ink flow. But springs in valves of the dampers may be stronger (case 1). Or may be valves not close completely (case2).
Start the print. When the colors starts missing open front cover for make a pause and check the printhead surface. If no drops on printhead - case 1, If you will see drops - case 2.
Also check blocking valves in ink lines between cartidges and printhead.

I’ll check that out on Monday when I get back to the shop.
The new OEM Mutoh dampers will arrive then as well. I will keep the old maintenance station just in case that it is still good. I have a VJ-1624 I can put it in. I also sent in the old head for cleaning. I can put the old cleaned print head in the old VJ-1624 as well.
I’ll let you know if the new OEM dampers makes all the difference on the VJ-1324 where I already replaced the head and maintenance station. That would certainly be a learning lesson for me!

Thanks again Umca for the info.

 

[GatorTPK]

I installed the OEM Mutoh dampers and they work great! Now I have a couple different issues, the ink output seems too high, it’s bleeding on the edges of colors especially black on yellow. Also a few nozzles on one magenta row aren’t working, possibly because the head was starving for ink for a few days and the nozzles dried up? Attached are a few cropped photos that hopefully show the detail. Is the blotchiness caused by too much ink and is that remedied with the RIPing software?

 

[Umca]

Ink bleedeng can be caused by low temperature of heaters.

 

[GatorTPK]

Umca, thank you again! The heater temperature was always ok before, but apparently with the greater ink flow, higher temperature fixed the bleeding issue. It was an obvious fix that I didn’t think of because it was never an issue before.
Also, I get perfect nozzle checks now, the magenta nozzles cleared up on the brand new head after having bad dampers restricting the ink flow.
Do you know of another source for good dampers (solenoid head assembly) that are good but less than $82 each? I have an old VJ-1614 and VJ-1624 that I use with lower quality media (banners, etc) and it would be nice to get them working better. I think better dampers may help after having my recent experience with generic dampers.
Thanks again!