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Author Topic: Epson 7900 from the inside - out  (Read 1092778 times)

davidh202

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Re: Epson 7900 from the inside - out
« Reply #1180 on: January 17, 2013, 09:53:39 pm »

When I ordered extra wipers from Compass Micro last year I asked about the cleaning solutions Epson used to sell and was told they were only available in 55Gallon drums to the tech people.
This is probably what Hal sent.
I do imagine that due to environmental and safety reasons Epson withdrew it from the general public...
Especially California, which has a warning label on just about everything produced today.
I'm surprised they even allow the sale of Banannas in Cal. since if not properly disposed of, the skin can be a serious   hazard. ::)
David
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davidh202

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Re: Epson 7900 from the inside - out
« Reply #1181 on: January 17, 2013, 10:11:10 pm »

Chaddro,
All these places that sell these cleaning "solutions" always have a disclaimer that the product will not be effective if you have burned out the head. Even Ericks guy "Oh Canada" had this disclaimer on his site.
I may be wrong but I believe that most people that have serious "clogs" and have done multiple power cleans have already done too much damage to their head, and cleaning is no longer an option. It all boils down to just how much repetative, consecutive cleaning, will do damage to the head.
 
I hope I'm wrong...
David
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Mark D Segal

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Re: Epson 7900 from the inside - out
« Reply #1182 on: January 17, 2013, 10:26:14 pm »

Chaddro,
All these places that sell these cleaning "solutions" always have a disclaimer that the product will not be effective if you have burned out the head. Even Ericks guy "Oh Canada" had this disclaimer on his site.
I may be wrong but I believe that most people that have serious "clogs" and have done multiple power cleans have already done too much damage to their head, and cleaning is no longer an option. It all boils down to just how much repetative, consecutive cleaning, will do damage to the head.
 
I hope I'm wrong...
David


I don't think you are wrong, I have seen advice NOT to do consecutive power cleaning, and I suspect doing even more than one without running prints through the system between cleanings could be deleterious.
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Mark D Segal (formerly MarkDS)
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Eric Gulbransen

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Re: Epson 7900 from the inside - out
« Reply #1183 on: January 17, 2013, 11:12:38 pm »

I for one don't know what deleterious means but I have spent a lot of time peering around the insides of these heads.  So far I have never come across something looking thinner on one chamber in areas, bent, having different sized holes, or looking worn out.  It is my opinion, which has been developed by listening to the many fateful stories that I have heard about heads with un-clearable clogs, that these problems aren't lite switch type problems.  What I mean by that is they don't reach 100% terminally clogged in a week.  From what I understand many of these deadly clogs were first troublesome, but to a degree manageable.  Until they were not anymore.

What I have actually seen while exploring the microscopic world inside these heads is that many chambers have hardened ink lodged inside of them, but at the bottom of the chamber, so at the top ink is still passable.  While other chambers are completely clogged, floor to ceiling.  If you keep this paragraph in mind, and now recall the one that preceded it, you might now consider that power cleanings (which are the cleanings that fire the piezos - which flex the sometimes unflexable ink-locked walls) are most dangerous when we need them the most.  My bet is that a semi-clogged chamber will benefit greatly from a power cleaning, because the movement and heat will dislodge the semi-hardened ink and discharge it from the head.  My other bet is that a fully clogged chamber, with it's chamber walls locked from moving while the piezos are firing, is the chamber that is doomed to permanently fail.  I don't think there is a semi-fail, a close to fail, or an about to fail head.  I think your head is failed, or not. 

Definitely print between cleanings, like Mark says.  And definitely do no more than, quick, somebody pick a number, (1?) power cleanings before you resort to plan...  "D" - which is we don't know yet.

In my opinion you do pairs cleanings first.  If that doesn't work you try them in serviceman mode, there are four different levels.  If by then you still have your clogs, try power cleaning.  But after one power cleaning if your clog is still there, maybe you've got a problem the machine itself cannot solve.  Once those piezo's can't flex, your machine's hands are tied.  But I really think it's too early to consider it dead.  Maybe bury it, but tie a string to it's big toe with a bell on the end of it, just in case.  In the mean time, I'll be on the graveyard shift. 

chaddro

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Re: Epson 7900 from the inside - out
« Reply #1184 on: January 17, 2013, 11:55:49 pm »

Well, the standard "paired" cleaning should not damage the head at all. There is no piezo firing associated with this. The capping station just SUCK the ink out.

The problem with SUCKING the ink out (and not firing any nozzles) is that a fluid will always flow in the path of least resistance. So there is no way for the cleaning station to target just the problematic nozzles. Say one color channel drops... you keep cleaning to NO avail because ink gets sucked out the other color in the pair: the path of least resistance.

So I was thinking. What about adapting a syringe with a rubber seal on the tip that you can use to target say 5 or 6 nozzles at once? Like a regular cleaning, but targeted. Not the small tipped syringes, but the large ones that vets use when feeding animals, etc. If we knew how much sucking force the standard cleaning creates, you'd have an idea of what is safe and you could apply cleaning in a more directed approach. I have thought that a small aquarium pump might work. You could use regular vinyl tubing with some kind of o-ring on the end. Sorry if this sounds crazy. Just thinking out loud here.

As side story about cleaning... a couple years ago I bought a Fuji Q4 Pro HVLP off ebay. Was owned by a custom cabinet making shop. Got a GREAT price on it. At least I thought I had. When it arrived, it turned out that the last time it was used, it wasn't cleaned. Everything was glued together with a white epoxy base enamel paint. It took me HOURS and plenty of acetone to get the spray head pristine again - slowly, layer by layer! Seriously, HOURS!

If the RED fluid works Eric, and can dissolve dried ink, I suppose the real question is how long can the head be exposed to the RED before it starts to dissolve things other than ink!

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chaddro

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Re: Epson 7900 from the inside - out
« Reply #1185 on: January 17, 2013, 11:58:17 pm »

Eric, you posted while I was writing! But I agree with you. If 1 power cleaning won't clear the clog, you have a big problem. Maybe time to take the head out and soak it in the RED stuff, or it's equivalant!

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Eric Gulbransen

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Re: Epson 7900 from the inside - out
« Reply #1186 on: January 18, 2013, 01:48:25 am »

Trust me chaddro by weekend's end we will know how long is too long, and why it is too long.  But first I have to find out if I can even get more RED.

As for your suction idea I appreciate that type of thinking.  Creative thinking.  So here is more food for more (creative) thought;  one channel that I recently took apart was so packed with ink that the hardened yellow ink actually kept the shape of the nozzle opening after the top of the channel had been removed.  Doubt I'm explaining this well enough to give you the picture but suffice to say sometimes our clogs are very well established.  Under a microscope, which is the only way to see this stuff, under 280x magnification you get an idea of size relationships.  If the nozzle opening has a diameter of 1, then a nozzle chamber has the width of 3, a depth of 8, and a length of maybe 40.  No matter how you slice it, or how you suck it, that's a 960lb block of ink trying to fit through a 1lb opening, with nothing to dissolve it but the same ink that formed it.  ...that's one hell of a challenge. 

Blue moon

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Re: Epson 7900 from the inside - out
« Reply #1187 on: January 18, 2013, 03:28:01 am »

Trust me chaddro by weekend's end we will know how long is too long, and why it is too long.  But first I have to find out if I can even get more RED.

As for your suction idea I appreciate that type of thinking.  Creative thinking.  So here is more food for more (creative) thought;  one channel that I recently took apart was so packed with ink that the hardened yellow ink actually kept the shape of the nozzle opening after the top of the channel had been removed.  Doubt I'm explaining this well enough to give you the picture but suffice to say sometimes our clogs are very well established.  Under a microscope, which is the only way to see this stuff, under 280x magnification you get an idea of size relationships.  If the nozzle opening has a diameter of 1, then a nozzle chamber has the width of 3, a depth of 8, and a length of maybe 40.  No matter how you slice it, or how you suck it, that's a 960lb block of ink trying to fit through a 1lb opening, with nothing to dissolve it but the same ink that formed it.  ...that's one hell of a challenge. 
In other words, the 1 against 960 is samson versus goliath......our mothers would have gone for the cod liver oil (guessing) and we would-be on our way to the loo in no time...son your just constipated...!
And of course from Epsons perspective the 1 droplet at a time that does get through the tiny aperture of 1 must have power behind it (960 bits of power) ...and great speed and controllability....(guessing again )
What you are allowing us to see and think about for the very first time Eric is that the flexibility of a Piezo chamber is USELESS unless it has flexible ink to play with....
Knowing you.......you probably wont be happy until you can prove that excessive power cleaning actually DOES damage piezo walls....and no doubt you will produce a photgraph of the damaged wall to prove it !!
On the other hand,possibly the hardening ink takes the rap and protects the wall behind it....you will tell us all in your own time
No tv for me this week-end
Good on you Eric
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davidh202

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Re: Epson 7900 from the inside - out
« Reply #1188 on: January 18, 2013, 11:14:04 am »

What I have actually seen while exploring the microscopic world inside these heads is that many chambers have hardened ink lodged inside of them, but at the bottom of the chamber, so at the top ink is still passable.  While other chambers are completely clogged, floor to ceiling.  If you keep this paragraph in mind, and now recall the one that preceded it, you might now consider that power cleanings (which are the cleanings that fire the piezos - which flex the sometimes unflexable ink-locked walls) are most dangerous when we need them the most.  My bet is that a semi-clogged chamber will benefit greatly from a power cleaning, because the movement and heat will dislodge the semi-hardened ink and discharge it from the head.  My other bet is that a fully clogged chamber, with it's chamber walls locked from moving while the piezos are firing, is the chamber that is doomed to permanently fail.  I don't think there is a semi-fail, a close to fail, or an about to fail head.  I think your head is failed, or not.  

Definitely print between cleanings, like Mark says.  And definitely do no more than, quick, somebody pick a number, (1?) power cleanings before you resort to plan...  "D" - which is we don't know yet.

In my opinion you do pairs cleanings first.  If that doesn't work you try them in serviceman mode, there are four different levels.  If by then you still have your clogs, try power cleaning.  But after one power cleaning if your clog is still there, maybe you've got a problem the machine itself cannot solve.  Once those piezo's can't flex, your machine's hands are tied.  But I really think it's too early to consider it dead.  Maybe bury it, but tie a string to it's big toe with a bell on the end of it, just in case.  In the mean time, I'll be on the graveyard shift.  

I am confident ,and have said a few times now, that it is indeed excessive power cleans killing the heads.
Are you so sure that Oh'Canada blew out your head with too much pressure,or was it already burned out due to tooo many power cleans?
http://www.luminous-landscape.com/forum/index.php?topic=61585.msg585320#msg585320
David
« Last Edit: January 18, 2013, 11:17:36 am by davidh202 »
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Eric Gulbransen

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Re: Epson 7900 from the inside - out
« Reply #1189 on: January 18, 2013, 11:35:07 am »

Why do I think the clearest first thing in the morning?

Here is some food for thought, before the weekend's fun begins, on the subject of growing clogs.  It has been my experience, and the experience of quite a few others who have chimed in here, that after doing power cleanings their clogs sometimes are worse instead of better.  This has never made sense to me until now.  Now I'm not saying I know why this happens, more I am offering an idea.  Consider just two adjacent chambers - one fully clogged with dry ink on the left, the other only partially with dry ink on the right.  The right chamber still fires because ink still passes through the upper portion of the chamber, but it's in jeopardy.  The left chamber does not fire at all.  So you do a power cleaning.  This fires all chambers, all walls are charged, they all get hot, they all flex - except the wall between our two chambers because the chamber on the left is frozen stuck.  Perhaps this heat, with no movement of the chamber walls, actually bakes the already building clog in the right chamber - causing it to grow instead of shrink.

I don't know, this is just an idea.  But it could support some reason to what is otherwise, so far, a perplexing phenomenon.

Eric Gulbransen

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Re: Epson 7900 from the inside - out
« Reply #1190 on: January 18, 2013, 11:39:46 am »

I am confident ,and have said a few times now, that it is indeed excessive power cleans killing the heads.
Are you so sure that Oh'Canada blew out your head with too much pressure,or was it already burned out due to tooo many power cleans?
http://www.luminous-landscape.com/forum/index.php?topic=61585.msg585320#msg585320
David

That's a great question and I have a great answer.  I am sure our head was functioning before we sent it to Canada.  In fact it printed, minus the drop-outs, fine.  We only had un-clearable clogs in two colors, and those clogs were small percentages of the channels.  Our clogged channels were actually mostly clear.  There is a pic of our last nozzle pattern on page one.

chaddro

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Re: Epson 7900 from the inside - out
« Reply #1191 on: January 18, 2013, 01:40:04 pm »

The more we talk about this, the more I can almost image what's happening in the head.

Remember, the Piezo element is in the TOP of the chamber. This was detailed in those recent posted docs (the patent one and the other, don't remember...)

When you do a power clean, perhaps all you are doing is COMPACTING he already sludgy ink, and allowing more sludgy ink into "damnation alley".

Also, there MUST BE a problem with Epson's new fancy paired capping station technology. To do something like have a solid blocked channel would take weeks and weeks of air exposure to cause this to cake up.

Now, add normal head operation, and maybe we're BAKING the ink into a toothpaste like substance until it finally hardens like concrete.

And while I'm on a roll... if this kind of clogging is gradually building up (like plaque in your arteries!), perhaps the head need to be taken out and flushed one a year to keep everything nice and shiny inside???

Or, less drastically, just fill each damper with the RED STUFF... let sit an hour (or so) and then a standard cleaning...???
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Alan Goldhammer

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Re: Epson 7900 from the inside - out
« Reply #1192 on: January 18, 2013, 05:16:50 pm »

I think Chaddro is correct about this assessment and the more I think about this I suspect that a head that gradually is exposed to air will cause these kinds of problems.  The capping station tolerance has to be pretty well sport on to prevent this kind of problem.  The only other possibility in my mind is poor quality control in the ink manufacturing process where there are some oversize particles that plug things up (though I don't think Epson would say this is the case).

Alan
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davidh202

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Re: Epson 7900 from the inside - out
« Reply #1193 on: January 18, 2013, 05:29:35 pm »

Why do I think the clearest first thing in the morning?

Here is some food for thought, before the weekend's fun begins, on the subject of growing clogs.  It has been my experience, and the experience of quite a few others who have chimed in here, that after doing power cleanings their clogs sometimes are worse instead of better.  This has never made sense to me until now.  Now I'm not saying I know why this happens, more I am offering an idea.  Consider just two adjacent chambers - one fully clogged with dry ink on the left, the other only partially with dry ink on the right.  The right chamber still fires because ink still passes through the upper portion of the chamber, but it's in jeopardy.  The left chamber does not fire at all.  So you do a power cleaning.  This fires all chambers, all walls are charged, they all get hot, they all flex - except the wall between our two chambers because the chamber on the left is frozen stuck.  Perhaps this heat, with no movement of the chamber walls, actually bakes the already building clog in the right chamber - causing it to grow instead of shrink.
I don't know, this is just an idea.  But it could support some reason to what is otherwise, so far, a perplexing phenomenon.

Makes a lot of  sense and very good logic  to me!!!
David
 
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Eric Gulbransen

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Re: Epson 7900 from the inside - out
« Reply #1194 on: January 19, 2013, 02:09:17 am »

There I sat tonight, pondering more money spent, and the week or so it will take for my shipment of RED to arrive.  Until then I have only a tiny bottle to experiment with.  I sat, I thought, I finally grew impatient.  I've watched RED circulate it's way around piezo chambers enough already.  I know what happens in an hour, I know what happens in a day.  WTF am I waiting for..  I removed the un-clearable clogged head from this dead 9900 that I bought from Edward the Juggler in Colorado, for the second time in a month.  Last time I used gentle fluids, knowing full well they most likely wouldn't work.  I knew the head would be out again.  This was a learning experience.  I was fine with that.  But tonight after work I went back to page-1 of this thread, and read from top to bottom.  Funny, quite a few responses went missing, but that's not what grabbed me most.  The date of post-1 did.  Lord forgive me it's almost a year to the day. 

I knew a lot already in my first post about these machines, but at the same time I knew very little.  Man have we come a long way in a year.  But we still can't clear un-clearable X900 clogs.  Not yet anyway, which finally got my goat.  I dumped the little RED I have left into my soak tank and set ole 99 face down in the juice.  I drew RED up into each channel, particularly focusing on green - which is 98% dead.  I sealed the tank, stowed it in the cabinet, and there it will sit til tomorrow.

HAL warned me "nobody knows what it does to 900 heads.  Don't leave it long".  Well I'm gonna know what it does to 900 heads.  And soon so will you.

...you had to figure the framing hammer was coming sooner or later

JeffW

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Re: Epson 7900 from the inside - out
« Reply #1195 on: January 19, 2013, 09:29:03 am »

Eric,

Are we to the point of posting another thread, just to condense what would be a good guide for those looking for help. I want this thread to keep going, great stuff. Just thinking it would be great for someone looking for help to not have to weed thru all this to find some simple advice. Thanks for all the work you have done.

I think in another two or three days I will finally be back to printing after being down for FIVE months. Yes this last clog has taken me this long to clear.
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davidh202

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Re: Epson 7900 from the inside - out
« Reply #1196 on: January 19, 2013, 10:38:30 am »

Seems to me that the only worry from leaving it too long would be softening and delamination of the adhesives bonding the layers together.
Lets hope this is not the case. ;-) 
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Eric Gulbransen

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Re: Epson 7900 from the inside - out
« Reply #1197 on: January 19, 2013, 04:16:59 pm »

You have GOT to be kidding me...

Head back in after soaking in RED all night.  Everything functions perfect.  Head is recognized, nozzle patterns razor sharp, life is good - except for green.  Still 98% MIA.

This is my theory as to why:

Alan Goldhammer

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Re: Epson 7900 from the inside - out
« Reply #1198 on: January 19, 2013, 05:59:02 pm »

Maybe it needs some Dranoâ„¢
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na goodman

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Re: Epson 7900 from the inside - out
« Reply #1199 on: January 19, 2013, 07:39:06 pm »

Eric, I have the clear. I have had it for a long time. It's in its original bottle with Japanese writing on it. Can you read Japanese?
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