As always, thanks for the detailed post. I'd say this topic could be transformed in some sort of advanced tutorial of things new DTF users might not even have considered!
Especially because of this I wrote earlier:
All what we're discussing here falls precisely in that realm.
Back on topic, this makes perfect sense: I might really well start thinking at air as the main cause. I would think it can be a pretty common issue with cheaper converted printers.
I have to say this is tingling me in thinking at possible solutions, perhaps even silly ones!
Now I'm really just thinking out loud, given one of the main things is not to have air and not to suck debrees from tanks.
Wouldn't be nice to have some sort of "vacuum maker" to prevent air from flowing in the tube, even in case it's sucked from the tank?
Not this, but this pic gives the idea of the placement.
"Something" that sits across the tank and the damper which would be responsible to avoid any air to pass through, and/or to host filters to help stop any possible debree.
With something similar to "air locks" used for pipe systems, perhaps?
That sort of thing could be also an easier to access part where to do the vast majority of cleaning.
In general, making DTF's daily life easier in any possible way will, in time, pay back with a wider userbase and associated improvement of tools fo any kind.
Even finding a "simple" answer to a silly question like "what if I have to leave my printer for 2 weeks" would go in the same direction. There are just so many opinions out there, and often conflicting ones...
I'd say this is why I like posts like this. All is explained, perhaps even too much, but gives taste of real world... with pictures too!
And, most important, not just ending up with "what to do", but "why doing it". Makes a pretty good difference!
I do want to point out, 5 head cleans in a week isn't that much. Generally I do about 3-4 a day. 2 to get going, and 1-2 throughout the day as needed. When I change dampers, I usually do 5-8 strong cleanings depending on to remove the air from the system. whatever it takes to fully remove the air from the system. That is after I prime the dampers.
Your head cleans should be based from the nozzle checks you do, and printing with clogged/blocked nozzles can and does damage the head relatively quickly. Nozzle checks are the #1 way of determining the condition of the entire thing and helps break down where the problem is from one nozzle check to the next. I do not see any of that posted.
So for example, if you changed the dampers, did 1-2 head cleans and that was that- you very likely didn't pull all the air out of the system, allowed air to remain in there and could potentially damage the new printhead again. running the WIMS doesn't do that for you entirely.
When you have a shared capping station, like this machine likely has, it will pull from the easiest flowing location first. Air can act like a " block" and then that channel doesn't actually get flushed/purged as you would think, leaving an issue like this as well. with individual tanks it makes it obvious, with a shared ink tank it isn't and easily not noticed- which can make or break the whole situation.
So for example, On my machine it shares 2 channels per " capping pad". If one channel is clogged, and the other isn't, it's going to pull from the easy channel more, if not entirely. However, if there is an issue, it will suck the one channel with no/poor flow from the other, when removed from vacuum it will suck air right back up into the head of the slower flowing/no flowing channel if the ink isn't flowing properly. If it sits at all, high potential for a damaged printhead. If any of air is getting in around the dampers, connections, or anywhere else at all, it will continue to do so without properly sucking the ink. Without a seal, there is not going to be a good flow of ink. I have on numerous occasions, especially with aftermarket dampers ran into this.
Air is the enemy here and making sure it's entirely gone is the #1 thing to do all around to run and operate these machines effectively and efficiently.
It's very likely something within the message, something that was looked over, because if it were all on point, it would work if the printhead is new and not a dud.
on a side note, there is a white layer on the bottom of that ink tank, if it's there, it will also be in the ink lines. With a printer like this I had to physically shake the tank all the time or else this happened, and what you described. it can begin after one day.
The #1 thing I have found to be the reason for someone having no issues, to a ton of issues that new parts don't fix is going to be the accumulation of the white ink because it's not properly taken care of.
Also, both dampers takes the white from the same tank. Once more, the curious thing is still why it happens on one channel only. If debrees, I'd expect a little to happen on both, while today's test shows a huge difference between channel 1 and 2