Where's the leak?

[letterman7]

I've searched through the threads and kinda narrowed down this as an only possibility. My yellow damper has just recently started becoming cross contaminated overnight. It's happened twice in the past two days, and I can't quite figure where the leak is coming from. I'll put a new damper on, pull the ink through with the syringe, but I don't ever see any bubbles coming in with the ink. The cleaning station/pump assembly are brand new, as in two weeks ago as is the color head (had a major fubar with the colors, figured it was time to do a major overhaul). For a temporary measure until I get some more dampers in, I'm going to have to pull the yellow one off the carriage (or pull the sponge out of the spitter). Any clues anyone?
Thanks,
Rick

 

[h82loose]

cross contamination usually comes from the capping ststion. If the inside of the cap is touching the bottom of the head, it will wick the ink between nozzles. It could also be a thread or other contamination on the bottom of the head. Which Mutoh is this?

 

[letterman7]

It's a Falcon II Outdoor. I'll check for lint again...there were a couple threads from the large black spit pad on it, but I thought I got them all. I am also considering the possiblilty of the uneven ink levels in the carts. I did read where a low cart can siphon up a color next to it, and the yellow was the lowest of the carts until I replaced it today.

 

[henryp]

It's a Falcon II Outdoor. I'll check for lint again...there were a couple threads from the large black spit pad on it, but I thought I got them all. I am also considering the possiblilty of the uneven ink levels in the carts. I did read where a low cart can siphon up a color next to it, and the yellow was the lowest of the carts until I replaced it today.

Yes, uneven cartridge ink levels is mainly the cause of ink cross contamination on some older Mutoh printers (printing and cleaning cycles can build up enough negative pressure on a near empty ink cartridge that can cause it to suck ink from another cartridge that has plenty of ink on it when the printer becomes idle or is switched off). This is no longer an issue with the new ValueJet series that use 2-way valves to control the ink flow from the cartridges to the subtanks. These valves are normally closed and only open up when the subtanks reach a pre determined ink level (subtank empty condition). I have been working with Mutoh printers for several years and this is one of the innovations I really like about these new models.

 

[letterman7]

Good to know, Henry. It's the little things like that you won't read on the literature. I can't really complain too much about the printer. When it works, it's great. A little slow, but that's just fine. I can set it and basically forget it and go do something else. When it breaks...ah well...it's only money