My most recent focus has been finding the proper chemical to dissolve dried HDR Ultrachrome Ink. We found that, but the deadly clogs persist. We can only reach a small percentage of the two ends of these clogs, but the meat of the clog is untouched. The next step in this direction is soaking longer, which I have decided against. I am changing tack. It's too dangerous I feel, soaking with RED too long. The reason for this is very simple. Each channel runs two inks. The most delicate link in the chain which keeps these two separate inks separate, is the bond of the printhead face to the piezoboard. Once this goes soft, green and orange won't be green and orange anymore, instead they'll both be brown. If your head hasn't died yet in the face of cleanings, this will kill it for sure.
These piezoboards are amazingly intricate. Even though I have a stereo microscope, and can see these boards in great detail, I have to admit they are elusive things to map your way around. They are very difficult to light under the scope, and depending on how you light them they can and do change their shape straight before you. This makes it very difficult to understand exactly what you are seeing. Then there is the fact that typically they are caked with dried ink. It's a challenge. But recently, after the successful cleanings with RED, I have got some clearer views of these things under the scope. Another discovery was viewing them while submerged in water. This cleared things up even more.
What I have confirmed now is that the line of 358 consecutive chamber walls are indeed built on one horizontal deck. I knew this before, but what I did not know is that the deck they are built on is actually transparent. The next thing I learned recently is that beneath these transparent chamber wall lined decks, there is a second open reservoir containing free flowing ink which runs UN-compartmentalized, for both the width and the length of the entire deck. Stick that in your hat and consider what's next..
Upon the very closest, submerged in water under halogen lights examination I have managed to perform to date, I have discovered that at one end of each piezo chamber, at the very bottom, directly downward from the placement of the nozzle opening in the printhead face, there are incredibly tiny "steps". Three total. I cannot confirm what they are at this point, but I am suspect that they might actually lead to the un-compartmentalized ink reservoir below. Why you ask do I think this, if we already know ink is supplied to the chambers by passing through the tiny space over the "speed bump"? I have no $U*O%&)#$-ing idea, yet, but I do have an unsolved mystery to share which may be related..
*paragraph note: when I say "pressure" I am talking nearly immeasurable pressure.
When you create negative pressure at the rear of the head in order to suck fluid up through the face of the head, you get resistance. When you apply positive pressure to the rear of the head in order to push fluid out the face of the head, you get resistance. Nothing happens. But after a while of soaking things do begin to move. It does become possible to both draw fluid up through the face of the head into the chambers and out the back, and to push fluid through the chambers and out the nozzle openings in the face. So here-in lies the mystery; how in the love of $*)%! can it become possible for both cleaning fluid, and ink mind you, to both exit and enter the chambers through the nozzle openings, if the chambers are still clogged so solid that they don't fire once back in the machine? It can't of course, which brings us farther down this rabbit hole..
I have been sheepishly dodging my shadows for the past week about the fact that in reality I do not know how these heads work. Not REALLY work anyway. I mean, I have seen plenty of diagrams of piezoelectric nozzles by now. But none of them look like what I see in these X900 heads. So what gives?
I now think there could be two ways ink flows through the last elements of these printheads. I also now think this is why we have the variety of cleanings that we do. What if ....and I realize this is a big "IF".... these flexing chamber walls don't flex at all? What if they're just walls? And what if there is more to these X900 piezo nozzles than simply a hole in the roof at the end of an ink-filled hallway? What if these "steps" are elements of an actual nozzle, supplied not by the ink in the chambers, but by the reservoir below? The successful firing of these nozzles could in some way relate, perhaps via pressure (negative or positive), to the ink inside these chamber walls?
Stay with me for a minute here..
If a pairs cleaning "sucks" ink from the face of the printhead without firing the nozzles, it's main purpose could be simply to draw ink through the chamber passages, cleaning them instead of the actual nozzles ("steps") themselves. It could be that power cleanings, the cleanings that actually fire the nozzles as well, are intended to clear the firing elements of the actual nozzles. Lastly, if heat plays a role in all of this, and we know that it does because anywhere you have movement you have friction, which is heat, added to which we have piezoelectricity which is also heat - then it could be that these chamber walls play a major role in cooling as well as the passage of ink. Let me say that this way, could it be that these chamber walls play a key role in cooling as well as the passage of ink? Could this by why ink has such a tendency to dry up between them, because they dissipate so much heat? ...Especially in power cleanings - which is why deadly clogs often get bigger after power cleanings?
I apologize for all the words. I don't understand this. I am trying to. Definitely I got ink to both enter, and exit the printhead face via pressure from the ink supply nipples in the back of the head. Yet the machine couldn't fire the nozzles. I know ink is intended to pass through those chambers as part of the firing process. How else would the ink help cooling, if it were not moving? That passage of ink through the chambers likely plays two roles. And ink exits our heads from two different routes.