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Author Topic: Epson 7900 from the inside - out  (Read 1083031 times)

gwhitf

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Re: Epson 7900 from the inside - out
« Reply #160 on: February 03, 2012, 11:29:08 am »

Make sure you have latest firmware. Somehow I did not have Epson Remote installed, and somehow that seems necessary for the Firmware Upgrade feature to be enabled. The driver walks you thru the Firmware upgrade effortlessly. It takes about fifteen minutes to achieve. Don't rush it.

For the record, my issue is still present. The same exact bars missing in the LLK channel every time, after repeated cleanings. I"m starting to think that the printhead might be damaged or breaking down.

I'm out of warranty. Two year old machine. Microbanding continues. Time to call Decision One I guess.
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Eric Gulbransen

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Re: Epson 7900 from the inside - out
« Reply #161 on: February 03, 2012, 09:31:15 pm »

Quote
I'm out of warranty. Two year old machine. Microbanding continues. Time to call Decision One I guess.

Please share what they say, what they do/propose to do, and what their estimated cost for the repair is (if you don't mind of course).  We've got to beat this thing..

As it stands now everything is in place for tomorrow's final assault on our 7900.  Just got back from the city where I stocked up on ink for our recharge.  Got a huge deal thanks to Justin, our ebay parts contact in SF.  I couldn't make Justin's 2pm deadline for pickup so I met his father instead.  Pretty cool guy.  We talked for a while.  I gave him my input on what I thought he should stock up on and why.  I even told him about this thread - and David buying one of his damper assemblies just to have on stand-by, most likely due to what we have shared here.  He seemed happy.  Just before we signed off I said, "Don't forget.  Keep your eye out for x900 printer heads.."  He responded with a classic smile - "You are my friend.  ...Come with me."  I followed him through a maze of printer parts boxes so impressively stacked even a Bloodhound would struggle to get through it.  About mid-way through the maze we arrived at his desk.  He reached from it's cluttered top holding toward my face a small square box in a manner suggesting it's worth was unparallelled.  "It's a 7900 print head.  Did you know they are made in Germany?"

Needless to say that was not the end of our conversation.  So nice to know at this point we have a backup plan.

Fingers crossed gentlemen.  Tomorrow is the day.

na goodman

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Re: Epson 7900 from the inside - out
« Reply #162 on: February 03, 2012, 09:47:25 pm »

And women, I can hardly wait.
« Last Edit: February 03, 2012, 10:07:25 pm by na goodman »
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Farmer

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Re: Epson 7900 from the inside - out
« Reply #163 on: February 04, 2012, 03:00:51 am »

It's not really measuring ink flowing through the nozzles, but rather ink being fired from them, using an electro-static method - it's a subtle but important difference.  It's so senstive, if your dot is not properly formed it can give a false positive that it's blocked (because it doesn't receive the correct return), although a misformed dot could be from something near the nozzle so cleaning isn't an entirely bad idea.
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Phil Brown

Mark D Segal

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Re: Epson 7900 from the inside - out
« Reply #164 on: February 04, 2012, 09:04:36 am »

It's not really measuring ink flowing through the nozzles, but rather ink being fired from them, using an electro-static method - it's a subtle but important difference.  It's so senstive, if your dot is not properly formed it can give a false positive that it's blocked (because it doesn't receive the correct return), although a misformed dot could be from something near the nozzle so cleaning isn't an entirely bad idea.


Hi Phil. Sensitive indeed and as long as one leaves auto-functions enabled it doesn't like being contradicted. On my 4900 yesterday, after not using it for three days, the manual nozzle checked showed a very small gap of two missing strokes in Cyan - so trivial I decided to ignore it and just print, because small gaps like that can just cure themselves from printing. Well, the printer didn't like that decision, so after sending the image to print, it did an Auto Nozzle Check and promptly launched an Auto Clean - I guess by way of showing me who's boss. :-) Fun and games. But I've decided to leave the Auto functions enabled, because I think although it may consume a bit more ink on maintenance than I would judge necessary myself, it's probably better insurance against cumulating issues. My only concern about this level of generosity to the cleaning system is whether it will consume the limit of the wiper blade counter sooner than desirable (desirable being a minimum of three years in my case).
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Mark D Segal (formerly MarkDS)
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gwhitf

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Re: Epson 7900 from the inside - out
« Reply #165 on: February 04, 2012, 09:43:35 am »

Attached is a scan of the LLK Nozzle Check block by itself. Every other color is just fine, and has been just fine. After many power cleanings, and individual color cleanings, the missing bars never change. It never gets worse; it never gets better. The same number of bars are always missing, and always in the same position. (Sorry for the lame scan of the bars; I pushed the Levels and Contrast, to show the effect, since the ink is very light LLK).

Also for the record, it seems that the printer does "know" that the LLK head is clogged, because it reports back to me, after some cleanings, that it does detect a clog. This is a dialogue box on the printer LCD. But like a person trying to scratch his own back, the printer cannot seem to fix itself; it knows it's sick, but it can't heal itself.

You'd think, even with these few bars missing, and all other colors just fine, that the micro banding would not be that pronounced, but it is, as shown in a prior post -- a scan of a detail area of a 13x19 print. I had a phone conversation with a very knowledgeable person on Thursday, and he suggested that the role of the LLK ink is also to be a slight degree of "varnish effect". I asked him if I could just "turn off" the LLK channel; he said you could, but only when using a RIP, (which I'm too cheap to buy).
« Last Edit: February 04, 2012, 09:54:55 am by gwhitf »
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clic

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Re: Epson 7900 from the inside - out
« Reply #166 on: February 04, 2012, 09:50:29 am »


4- a situation similar to dead pixels on an lcd or sensor, which would be dead nozzles due to them not receiving electrical signals to open. There should be some way to diagnose that. Is there a option in the self test portion of the service menu.?
I think a new head is definitely needed if that is the issue.



As mentioned before, I am studying this issue, and writing an article on this for Photo Technique magazine, as my own printer is affected by it. 

Other people that I have been in contact with and who had that issue, called D1, changed the head and then checked on the head which was then letting ink flow through ALL nozzles under pressure.  Changing the head though, was the step that resolved their problem.

I have installed cartridges with cleaning fluid in the LLK channel (tinted one from AIS, unlike what Eric used) in my printer, and was able to see that even with no more ink in the channel, the more I was cleaning, the more the channel was getting clogged.  That defies reason, as it is completely impossible that cleaning fluid would clog any nozzle in the universe.  That plus those other heads that were changed, yet had no nozzles actually clogged, lead me to believe that we are not talking here of actually clogged nozzle, but rather of some electronic not firing the nozzles that then appear "clogged" on a nozzle check.

The interesting factor here, is that in my research, I have found 13 cases that fit the pattern of illness, and all but one have that problem with LLK.  The 13th case is with green.  I have not found any case with any other color.  Eric could be one, but I hope that his problem is of a different nature, probably just regular clogging.

I have alerted Epson at the highest level on this, and am awaiting for them to get back to me after looking into the situation.  They were not aware of this.

Jean-Christian Rostagni
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Mark D Segal

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Re: Epson 7900 from the inside - out
« Reply #167 on: February 04, 2012, 10:56:27 am »


I must say also, that repeated attempts at multiple cleanings, especially power cleanings, is a definate no no!
David

That's correct David. Epson's advice to me in the past has been to run prints between regular cleanings for dealing with stubborn issues, and not to sequence power cleans one after the other. If one Power Clean doesn't clear everything up, call Tech Support.
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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 #168 on: February 04, 2012, 11:48:01 am »

I have installed cartridges with cleaning fluid in the LLK channel (tinted one from AIS, unlike what Eric used) in my printer, and was able to see that even with no more ink in the channel, the more I was cleaning, the more the channel was getting clogged.  That defies reason, as it is completely impossible that cleaning fluid would clog any nozzle in the universe.  That plus those other heads that were changed, yet had no nozzles actually clogged, lead me to believe that we are not talking here of actually clogged nozzle, but rather of some electronic not firing the nozzles that then appear "clogged" on a nozzle check.

Jean-Christian Rostagni



This has been my quiet suspicion as well.  Or maybe fear.  Could be electronic.  It's been about a week this idea has been wandering around my noodle.  After all how could a clog, or clogs in my case, sustain themselves even with cleaning fluid running through the head.  Only explanations I come up with are:

1 - Typical hardened ink lodged before, or on top of the "nozzle", which simply does not clear with cleanings. 

2 - Old damper let crap into the line, likely from old ink (I suspect both our PK and YW inks were opened longer than six months ago but I do not know this for sure, I bought this printer used.  The dates on these particular colors are 2010), which lodged itself just over these particular nozzles - because they were too big to go through.

3 - Dirty, old, crooked and compromised wiper (which we confirmed our machine had) left splooge on the printer head (which we confirmed it did), which compromised the seal of the capping station - which dried ink either over the nozzles, in the nozzles, or behind the nozzles in question.

4 - These nozzles in this head have stopped firing due to some electrical failure.  But who knows whey the electrical failure - maybe it's dried ink...


Right now I can confirm, because I saw it with my own eyes, there was debris in the PK channel lodged in our head BEFORE the nozzle.  I watched it come out into the clear hose of the syringe we used to suck cleaning fluid through our head in reverse direction.  I did not, unfortunately, watch the fluid come out of the YW channel.  Moron.

Either way, no matter what happens or why, later today we will all know a lot more about these clogging x900 heads.  I am confident that if our head still has the same clogs, after all we have done to it while it's been outside our machine, the source of this un-cloggable clog problem that none of us can seem to work through - lives behind door #4

Ernst Dinkla

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Re: Epson 7900 from the inside - out
« Reply #169 on: February 04, 2012, 11:57:33 am »


I have installed cartridges with cleaning fluid in the LLK channel (tinted one from AIS, unlike what Eric used) in my printer, and was able to see that even with no more ink in the channel, the more I was cleaning, the more the channel was getting clogged.  That defies reason, as it is completely impossible that cleaning fluid would clog any nozzle in the universe.  That plus those other heads that were changed, yet had no nozzles actually clogged, lead me to believe that we are not talking here of actually clogged nozzle, but rather of some electronic not firing the nozzles that then appear "clogged" on a nozzle check.

The interesting factor here, is that in my research, I have found 13 cases that fit the pattern of illness, and all but one have that problem with LLK.  The 13th case is with green.  I have not found any case with any other color.  Eric could be one, but I hope that his problem is of a different nature, probably just regular clogging.
 
Jean-Christian Rostagni


If pigment settling happens and that can be caused in more than one way and on different spots, you will see dampers clogging up. Rigorous cleaning steps can increase that build up on the sieves of the dampers and cleaning fluids are not the remedy in all cases where pigment particles agglomerate. So what may look like a clogged head could well be a starved head not getting enough ink supplied through the damper. There is a delicate balance of forces that keeps pigments suspended in inks, less pigment in more ink medium does not have to be an ideal base, the LLK could be an example. Yet I have seen all kinds of ink channels mentioned when Epsons clog and the LLK channel is not as dominant as you see it. I think statistically your observations are far from sound and the cause for the trouble may have a completely different base than you think. I agree there is an issue but I see no simple answer what causes it. It could be the rudimentary wiper technology if compared to what the 10000 had and the HP Zs have, it could be the frequency at which the droplets have to be squirted in competition with the Canon models. One thing is sure, the promise of coated heads with less cloggs, less banding, is not fulfilled in the x900 and 11880 models. It works far better on the 3880 though. A 180 nozzles per channel head that may not be as much challenged as the x900 heads are. I fear that Eric's brave adventure and the life report may enter another mood when the end of this thread comes closer. I have worked on Epson 9000s, a 5000 and a 10000 and when a head gets infected by particles of whatever kind (fungi included) it becomes extremely difficult to get them working normal again. Thank god for user replaceable heads, the more when they have the dampers/sieves included. What I write is what I call an opinion, mine, and not more than that. I'm glad there is no urge to write an article on this subject.

met vriendelijke groeten, Ernst
Shareware too:
330+ paper white spectral plots:
http://www.pigment-print.com/spectralplots/spectrumviz_1.htm
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Alan Goldhammer

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Re: Epson 7900 from the inside - out
« Reply #170 on: February 04, 2012, 12:20:16 pm »

Ernst raises a good point and I was about to say the same thing but was off on my morning walk.  Remember these cleaning solutions are not sanctioned by Epson and it's unclear what their effectiveness might be.  The clogs are caused by particulate matter and can be a function of a number of different things that have all been mentioned.  If a clog is big enough a cleaning solution is not likely to do much good unless you did a reverse suction to pull the clog away.  It's clear from this discussion that there are multiple factors at play here and maybe no easy solution.
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SacredEarth

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Re: Epson 7900 from the inside - out
« Reply #171 on: February 04, 2012, 01:05:34 pm »

Hello, I'm new to luminous-landscape, and I am so glad I found this forum. I had a rough month of January with Epson large-format printers. At the end of 2011 I decided it was time to upgrade my 9600. I won a used 9900 on eBay and found a new home for my 9600. The description on eBay stated that the printer "printed perfectly", but the auto nozzle check would not verify that the green channel was clean. When the guy delivered the printer I ran a couple of tests and it seemed to be printing green ok, but the next morning I did more tests and in fact the green was not printing at all. I was just seeing green in the test prints I did because it was using cyan to mix the dark greens, and the green ink is only really utilized on lighter greens(which I found out were all printing as yellow. I filed a dispute with eBay and I lost because they said if I knew there was a possibility of the green having issues I should have run more tests. This is true, It was late when the guy delivered the printer and I trusted that it "printed perfect". Lesson learned. So in the meantime I was out a fully functioning printer and I had orders backing up so I found an 11880 printer on eBay. I had this one shipped and when the freight truck arrived another crate had been set on the printer crate and smashed the whole top of the printer. By this time I was really regretting the upgrade and I had a lot of money invested in broken printers (btw, I did get reimbursed for the broken 11880). At that point I was desperate for a printer and I found two 9800 for $800. For both, so a friend and I bought them for $400. Each and it has been working great!
In the meantime I have this brick of a 9900 sitting in my studio that won't print green. I tried every cleaning cycle and the result was always the same-the middle of the green channel missing. Epson wanted to send out a decision one tech to replace the head at a cost of $2400.(parts & labor!) that's just about what I paid for the used printer. I am in the same mindset as Eric- I would rather take my chances trying to fix it myself. Before I started ripping apart the printer I thought I'd try everything I could externally to fix the printer. I bought the edi fluid and I had planned to fill an almost empty Epson ink cartridge with warm distilled water and fluid to flush the head, but after filling most of the cartridge with fluid (which was difficult) the printer would not recognize the ink cartridge.  This may be a blessing in disguise as I found this forum yesterday and read about what a horrible waste of ink this could be. I really thought the tilting the printer back and filling the cap with cleaning solution was a great idea. So this morning I pulled out my wiper in service mode and cleaned it. Then while the wiper was still visible I leaned the printer back against a table and manually pushed the wiper assembly up to access the cap station. I filled the cap up with a syringe using a 70% distilled water/30% EDI cleaning solution mix. It is soaking now. I will post an update later to let you all know how this worked. In the meantime I will anxiously be awaiting Eric's test print results. If this lean back method does not work, and Eric's head cleaning is successful, I think that will be my next course of action.
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Eric Gulbransen

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Re: Epson 7900 from the inside - out
« Reply #172 on: February 04, 2012, 03:17:56 pm »

Interesting.  and bold.  Had I to do it again this would be the last step I take before disassembling the machine.  Are you leaning it forward now that you filled the capping station with solution?  In my science fiction inspired vision I picture the solution just saturating the face of the print head, for hours and hours - but only if the machine is tilted forward.  Otherwise it'll just soak the bottom of the head.

*Disclaimer - I can't even say this is a recommendation.  More it's a creative (ok twisted) vision, inspired by desperation.

Mark D Segal

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Re: Epson 7900 from the inside - out
« Reply #173 on: February 04, 2012, 03:28:05 pm »

......... I think statistically your observations are far from sound and the cause for the trouble may have a completely different base than you think. I agree there is an issue but I see no simple answer what causes it. ............. I'm glad there is no urge to write an article on this subject.

met vriendelijke groeten, Ernst
Shareware too:
330+ paper white spectral plots:
http://www.pigment-print.com/spectralplots/spectrumviz_1.htm


Ernst - given your intimate knowledge from working with such a range of printers it is interesting to see you saying this, as I have the same impression - albeit from a lesser knowledge base - but still enough experience and reading to understand that there could be multiple causes of these problems - who knows - perhaps a batch of heads or some other assembly that weren't manufactured quite correctly, or a range of other factors which could differ from one complaint to the next even though the complaints may be about a similar outcome.

I also like to look at such issues from historical and market perspectives. This printer came into commercial circulation early 2009 and machines were available for testing late 2008. Micheal Reichmann reviewed it on this website (http://www.luminous-landscape.com/reviews/printers/7900-9900.shtml). It is now early 2012. Given what we know about how quickly product problems go viral on the internet, and the fact that large numbers of these printers have been working in all kinds of commercial establishments and private homes all over the world for several years, if there were really something systemically wrong with it, this would have been known, understood, widely and prominently discussed and most likely dealt with long ago. Not to say that late-blooming problems wouldn't have late-blooming discovery, but one really has to ask oneself carefully whether these problems relate to usage patterns, bad luck with a few handfuls of printers in a sea of many thousands, or in the worst case scenario - late-blooming "new" issues. One would hope and expect that competition between the major brands is keeping them all on their toes in respect of design, QC and support, understanding of course that when it comes to printing with pigmented ink, they all clog. What differs is how the clogs are handled in the product design (and therefore which approach may be more or less suitable for which kind of user). The Epson approach is more immediately self-evident.

All that said, it is good we have these forums for the airing of such issues, and like all of us reading this thread, I'm awaiting with interest the outcome of Eric's hard and daring work.
« Last Edit: February 04, 2012, 03:29:54 pm by Mark D Segal »
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Mark D Segal (formerly MarkDS)
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Re: Epson 7900 from the inside - out
« Reply #174 on: February 04, 2012, 03:36:48 pm »

Ernst:  You probably think of unresolvable clogs in other printers but the x900 when you say that you have encountered many on other than LLK, don't you?  Because between myself and another fellow, we have looked at all the posts mentioning clogs on the Epson LF forum for the x900 since the inception of that series, and same thing here  until 1 year back, and pretty much only found LLK ones, with the exception in green previously mentioned.

I also have spent hours talking with AIS, who is a De facto telephone center for folks who experience clogging with inkjet, and Scott could not remember any call for any other color but LLK for x900 printers.  I'll concede that these are more or less circumstantial evidences, but the odds that all other colors would have even unconsciously plotted to elude my search are not very good, hence my conclusion so far that there is a problem with LLK.  I am posting here so that people can prove me wrong, but remember, only x900 (and that does not include 4900 in this case).

I have also made a test on LLK ink, letting some dry at the air in a ramekin, and amazingly, that stuff does not dry, or more exactly does not harden, it becomes way thicker, like grease on a bicycle chain, but it does not harden.  It is hard then to imagine how it could do the kind of thing that Eric showed on the head capping station part of the head.

Alan, about the cleaners I used, they have been tested by AIS as being safe with x900 heads for up to 3.5 weeks, and once again, whatever problems was there, existed before the cleaners went into the head.  It just does not make sense that they would clog anything, especially two weeks after being introduced in the head.  And if they were causing delamination, they would most likely cause clogs randomly, not around the existing problem as is the pattern.  Again, I post here to hear some sensible contradiction.

Eric: the cyan and yellow clogs I saw on the picture of your head would most likely have been cleaned by putting the cleaners (007 and 007+) from AIS for two days or less on the capping station.  I hate to break you the news so brutally, but hey, if it was just that, we will all have learned nevertheless and your name will remain in our memory for a few centuries.  The gunk going out by reverse pressure, that you write about, seems more worrisome.

I also need to emphasize that the LLK issue that I write about, affects relatively few printers as far as I can see, but enough that there is statistical evidence, whether or not one factors in that a lot of printers from this series are under warranty, extended or otherwise. Only Epson mostly hears about the warranty cases which are nevertheless few enough that even they don't feel that there is the plague out there.

Can't wait to read the rest of the story.

« Last Edit: February 04, 2012, 03:44:06 pm by clic »
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SacredEarth

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Re: Epson 7900 from the inside - out
« Reply #175 on: February 04, 2012, 04:22:49 pm »

Go349, Bold, I don't know, desperate-maybe. I did tip the unit forward after capping the head with the solution, but I only let it sit for a couple hours. I just wanted to see if there was any results at all. I figured i could do it again for longer. I did a cleaning and ran a nozzle check, and the nozzle check looked the same. I also cleaned the wiper which had very little gunk on it. So after I tried that I placed a folded paper towel saturated with solution in the position where the head stops for the wiper replacement. Then I executed the wiper replacement command and the head moved over the paper towel with solution. While the head was parked there I used a syringe filled with warm edi solution and I injected warm solution onto the paper towel to over saturate it and cause it to swell up and meet the bottom of the head. I let it sit for about 30 minutes, and when I moved the head back the paper towel had a large amount of green gunk on it, but not really any other colors. This makes me think that the head is pretty clean except the problematic green channel. Still the nozzle check looks the same, but I think I am making some progress...
FYI, when I have spoken to The decision one tech he said that the green and light light black were the most common to clog because those inks are used the least and have a higher chance to clog due to the reduced amou t of ink moving through the head. He said that there weren't many people that utilize the full gamuts of the printer especially the extended green gamut.
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Alan Goldhammer

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Re: Epson 7900 from the inside - out
« Reply #176 on: February 04, 2012, 04:57:12 pm »

Ernst:  You probably think of unresolvable clogs in other printers but the x900 when you say that you have encountered many on other than LLK, don't you?  Because between myself and another fellow, we have looked at all the posts mentioning clogs on the Epson LF forum for the x900 since the inception of that series, and same thing here  until 1 year back, and pretty much only found LLK ones, with the exception in green previously mentioned.

I also have spent hours talking with AIS, who is a De facto telephone center for folks who experience clogging with inkjet, and Scott could not remember any call for any other color but LLK for x900 printers.  I'll concede that these are more or less circumstantial evidences, but the odds that all other colors would have even unconsciously plotted to elude my search are not very good, hence my conclusion so far that there is a problem with LLK.  I am posting here so that people can prove me wrong, but remember, only x900 (and that does not include 4900 in this case).
This is a small sample compared to the total installed user base of this printer and while they may be reporting more LLK clogs it's likely not statistically significant.  It also does not include and Epson authorized service calls done under warranty or extended service contract.  Unless we know those data it's difficult to do any firm conclusion.

Quote
I have also made a test on LLK ink, letting some dry at the air in a ramekin, and amazingly, that stuff does not dry, or more exactly does not harden, it becomes way thicker, like grease on a bicycle chain, but it does not harden.  It is hard then to imagine how it could do the kind of thing that Eric showed on the head capping station part of the head.
Did you look at any of the other inks?  All we know is from the MSDS for the various ink sets and I've looked at all of them (put something up on this site last year when there was a discussion about drying of inks).  The LLK and LK ink are pretty much the same in terms of components, both based on carbon black with glycerols and water as the solvents with the proprietary polymer encapsulation the remainder.  If anything this would point to an equal number of LK clogs.  I'm not sure what your ramekin test shows.  It clearly is not the same as looking at ink deposits on paper and if you put a large droplet down it's not surprising that you saw something that did not fully harden.  I wouldn't put much faith in this.


Quote
Alan, about the cleaners I used, they have been tested by AIS as being safe with x900 heads for up to 3.5 weeks, and once again, whatever problems was there, existed before the cleaners went into the head.  It just does not make sense that they would clog anything, especially two weeks after being introduced in the head.  And if they were causing delamination, they would most likely cause clogs randomly, not around the existing problem as is the pattern.  Again, I post here to hear some sensible contradiction.
This may be a perfectly good cleaning agent but my point is that it is not sanctioned by Epson and only users with out of warranty printers would be going down this route.  Because we fully do not know the chemical composition of the Epson inks, it is difficult to say whether this cleaner is the most optimal for that purpose.  As Mark and others have said these printers are quite complicated and clogs can arise from a variety of factors.  As I have noted in the past, I have a 3880 and so far have never had a clog.  How much different this head is from the x900 series, I don't know.

Alan
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Alan Goldhammer

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Re: Epson 7900 from the inside - out
« Reply #177 on: February 04, 2012, 05:00:51 pm »

FYI, when I have spoken to The decision one tech he said that the green and light light black were the most common to clog because those inks are used the least and have a higher chance to clog due to the reduced amou t of ink moving through the head. He said that there weren't many people that utilize the full gamuts of the printer especially the extended green gamut.
I don't doubt what he told you but I've observed on the 3880 that the LB & LLB are used almost in equal amounts.  This may be because I do a lot of B/W printing where LLB maybe used more than with color printing.
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jeverton

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Re: Epson 7900 from the inside - out
« Reply #178 on: February 04, 2012, 05:06:06 pm »

This is a small sample compared to the total installed user base of this printer and while they may be reporting more LLK clogs it's likely not statistically significant.  It also does not include and Epson authorized service calls done under warranty or extended service contract.  Unless we know those data it's difficult to do any firm conclusion.

Did you look at any of the other inks?  All we know is from the MSDS for the various ink sets and I've looked at all of them (put something up on this site last year when there was a discussion about drying of inks).  The LLK and LK ink are pretty much the same in terms of components, both based on carbon black with glycerols and water as the solvents with the proprietary polymer encapsulation the remainder.  If anything this would point to an equal number of LK clogs.  I'm not sure what your ramekin test shows.  It clearly is not the same as looking at ink deposits on paper and if you put a large droplet down it's not surprising that you saw something that did not fully harden.  I wouldn't put much faith in this.
I've also run this test on the LLK and Cyan and it's evident the LLK will not harden!

This may be a perfectly good cleaning agent but my point is that it is not sanctioned by Epson and only users with out of warranty printers would be going down this route.  Because we fully do not know the chemical composition of the Epson inks, it is difficult to say whether this cleaner is the most optimal for that purpose.  As Mark and others have said these printers are quite complicated and clogs can arise from a variety of factors.  As I have noted in the past, I have a 3880 and so far have never had a clog.  How much different this head is from the x900 series, I don't know.
Well, what would you then recommend for users and printers that are beyond the 3 year warranty period?  Do you just expect everyone to go out an replace the printers after three years of service?  Hmmm... and yes the print heads are different!

Alan
« Last Edit: February 04, 2012, 05:15:04 pm by jeverton »
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clic

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Re: Epson 7900 from the inside - out
« Reply #179 on: February 04, 2012, 05:08:46 pm »

FYI, when I have spoken to The decision one tech he said that the green and light light black were the most common to clog because those inks are used the least and have a higher chance to clog due to the reduced amou t of ink moving through the head. He said that there weren't many people that utilize the full gamuts of the printer especially the extended green gamut.

In my personal experience, I cannot remember any clog that required cleaning on the Orange and green channel in the two years I have had this printer, certainly not on the green, on the orange maybe, but very rarely.  Although those two colors are indeed those that people use less on average.  In other words, Orange is used way less than LLK, on average, yet I have not been able to find any trace of an unresolvable clog on the orange.

Now the green, you would be my second case, if your problems persist, plus 12 LLK!

AIS theory and mine, is that there is something in the LLK ink, possibly in the green one (?), that under some circumstances (that would go from manufacturing to ?) causes some internal degradation of the head, delamination (unlikely given the non randomness of the dropouts on a nozzle check) to electronic.

Any other theory?
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