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Author Topic: Epson 7900 from the inside - out  (Read 261097 times)
Mark D Segal
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« Reply #1220 on: January 21, 2013, 11:04:02 AM »
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New person here, old clog in a 4900.  Having read through all of this several times I remain amazed at your individual and collective persistance.  Here's a question, and let me know if this is the wrong place to ask it.  With one dead channel/color (in my case VLM), might it be possible to re-plumb the head and make use of the fact that there are two blacks, photo and matte?  In my mind's eye this is really simple, just a matter of unplugging and replugging two tubes at one end of the other of them.  Surely it's more complicated if not impossible.  But for those of us that have but one bad color, is it possible to re-map the colors, then for example put a VLM cartridge into the unused black (say the Matte black if we are printing on glossy paper)? 

Even if you had the confidence to start tinkering with the hardware, I highly doubt this would work. You need to think of the whole process from the image file numbers onward in how the software and printer driver combine to deliver instructions about what drops to put where. If the reproduction of say VLM is needed, I suspect the instruction is being directed at delivering ink from the VLM channel, which is hard wired in firmware, not where you happen to place the VLM cartridge.
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Mark D Segal (formerly MarkDS)
Author: "Scanning Workflows with SilverFast 8....." http://www.luminous-landscape.com/reviews/film/scanning_workflows_with_silverfast_8.shtml
Eric Gulbransen
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« Reply #1221 on: January 21, 2013, 11:17:15 AM »
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It's an interesting idea.  Chasing the option of switching MK with PK at the head and not mentioning it to the machine - for instance if your PK was clogged and you didn't need PK, kind of works in my mind.  Only problem is the hoses that connect at the head are not individual lines.  They are a bank of nipples fixed in two rows on the head, and a bank of hoses fixed at the base of the damper unit.  I can't imagine switching colors would be possible.  You'd be better off buying an MK cleaning cart, filling it with PK ink, and charging the line with PK instead.  Then just print using "MK".  That would handle switching your inks.  As far as actually printing on glossy paper while the machine thinks you have MK in the gun, I don't know..  Maybe profiles are different for more than just the blacks when printing on matte papers?
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Sal Baker
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« Reply #1222 on: January 21, 2013, 01:51:53 PM »
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It's an interesting idea.  Chasing the option of switching MK with PK at the head and not mentioning it to the machine - for instance if your PK was clogged and you didn't need PK, kind of works in my mind.  Only problem is the hoses that connect at the head are not individual lines.  They are a bank of nipples fixed in two rows on the head, and a bank of hoses fixed at the base of the damper unit.  I can't imagine switching colors would be possible.  You'd be better off buying an MK cleaning cart, filling it with PK ink, and charging the line with PK instead.  Then just print using "MK".  That would handle switching your inks.  As far as actually printing on glossy paper while the machine thinks you have MK in the gun, I don't know..  Maybe profiles are different for more than just the blacks when printing on matte papers?
It also seems feasible that mk and pk are different enough to merit slightly different screening approaches to work with the other colors.

Sal
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Eric Gulbransen
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« Reply #1223 on: January 21, 2013, 07:04:58 PM »
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I have interesting news.  Rather than continue with the guess work I decided to use my brain for a change.  I smashed a channel to bits, strategically of course, and combed my way through the wreckage like a forensic scientist.  I have confirmed the following:

1 - The chamber walls are not simply for cooling purposes.  The power leads that fan out from the base connection at the channel source, rise up through the piezoboard and individually connect to each and every channel wall, separately.  The electrical connection to each of the walls make contact at the base of each wall and run for the entire length of each wall.

2 - There are no "nozzles".  At least not in the traditional sense.  No nozzles in the chambers, no nozzles below the chambers.  Not even any power supplied to that area, that I can find.  These piezonozzles are a design I have not seen in any literature posted here, yet.

3 - There are (I believe) two ways for ink to enter a chamber - over the speed bump or up through the floor of the chamber directly under the nozzle opening.  So, flushing fluid through with pressure can have no affect on the dried ink lodged in-between the chamber walls.

4 - if there were no secondary passages for ink to enter a chamber, then pairs cleanings (where the machine sucks ink from the face of the head) would either suck the dried ink out the nozzle opening, or if the dried ink didn't move at all they would probably end up sucking the floor of a chamber up through the nozzle opening.  ....my current bet is the secondary opening in the floor under the nozzle is a one-way valve-type safety mechanism.  That's the feel they give when you put pressure on them in either direction.  No movement at first, then with more pressure suddenly they begin to flow.  Repeat, same thing.  Feels like a valve.

5 - there is a clear plastic membrane that seals the base of the piezoboards from the world (chamber) beneath them.  Only way into a piezoboard, is through the ink fill port.

6 - there is NOTHING beneath a chamber but a wide open reservoir filled with ink, which runs the entire length and width of the entire chamber deck.  Nothing below the "one way valve" into the chamber at all.  


I am more confident than ever that those chamber walls are indeed our nozzles.  Guess work, flushed..


ps - I have followed the electrical leads up through the chambers, into and through the piezoboards.  All the honeycomb holes you see in pics I have posted - I don't know what they are or what they do, but they have no leads.  Cooling is a decent guess.
« Last Edit: January 21, 2013, 07:35:59 PM by Eric Gulbransen » Logged

Blue moon
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« Reply #1224 on: January 21, 2013, 07:15:37 PM »
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It also seems feasible that mk and pk are different enough to merit slightly different screening approaches to work with the other colors.

Sal

I think Mark and Sal are close.....yes we can change pipes and chips relatively easily....but what i think will also be needing change are  the algorithms  to tell the printer to produce the same colours but with different pipes....or different colours with the same pipes...
Its a recalibration of the printers profile really....oh for that cleaning solution.......
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Eric Gulbransen
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« Reply #1225 on: January 21, 2013, 07:31:37 PM »
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More fun facts for the evening's appetite.  On the subject of ink cart shaking, which has come up quite a bit lately, I would like to add the ridiculously appropriate experience of a fellow racer on Luminous Landscape, my new friend Lee.

First off, this is how much Lee knows about what happens to ink left sitting in our carts too long:




In my book, that's a lot.  Lee takes every cart he gets, apart.  He drains the leftover ink from them and stores it all in clear plastic bottles, each color separate of course.  So I talked to Lee about an experiment I did with an old cart I had hanging around.  Told him I cut the plastic cart to shreds, gutted the insides, and cut my way into the foil bag that holds the ink.  He interjected "You found not one trace of sediment did you.."  I told him no I did not.  Then he emailed me this picture taken in his basement.  He said "Me either, and I've taken hundreds apart."  Lee also told me in all the bottles full of ink that he has stored, the only color he's ever seen settle at all is yellow.

So anyone paranoid about their inks separating and settling in the carts, or their lines, or their dampers, like the muck you need to shake from the bottom of an Odwalla protein drink, I think it's safe to say rest easy.  I don't know what Epson makes this ink out of, but that's impressive.
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Mark D Segal
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« Reply #1226 on: January 21, 2013, 07:46:47 PM »
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Interesting. On pages 23 and 129 of the manual for the 4900 Epson recommends that we shake the cartridges gently before installing them. They don't say why.
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Mark D Segal (formerly MarkDS)
Author: "Scanning Workflows with SilverFast 8....." http://www.luminous-landscape.com/reviews/film/scanning_workflows_with_silverfast_8.shtml
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« Reply #1227 on: January 21, 2013, 08:24:37 PM »
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Which would lead one to think that possibly the cartridges need to be agitated (even after installation) every now and then. I'm informed the Canon does that normally.

Perhaps I should mention I'm in the market for a 24" printer and after three Epsons I'm very much leaning towards the Canon...and this thread has mostly lead me there.
« Last Edit: January 21, 2013, 08:27:09 PM by JohnBrew » Logged

Sal Baker
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« Reply #1228 on: January 21, 2013, 09:22:02 PM »
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Eric - I hope you have the opportunity to tear apart a head from the 3880 which is relatively bullet proof compared to the pro Epsons.  It would be interesting to see if there are any obvious design differences that can explain why my 3880 can go 3 years, with 3 year old ink, and never clog. 

I've had a love affair with the 3880, but I'm another user ready to move to Canon for a 24-inch printer.  Epson finally has serious competition in the wide boy category.

Sal
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Mark D Segal
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« Reply #1229 on: January 21, 2013, 09:26:27 PM »
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Sal, the 3880 is a Pro printer in the Epson line-up. It also qualifies for Epson Pro-Graphics service. There is a definite difference in ease of maintenance between this model (including its 3800 predecessor) and the x900s. There is some opinion that the lower nozzle count per sq. in. may be the explanation but in truth and in fact we don't know. There could be so many differences throughout the whole ink delivery system, from cartridge to paper.
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Mark D Segal (formerly MarkDS)
Author: "Scanning Workflows with SilverFast 8....." http://www.luminous-landscape.com/reviews/film/scanning_workflows_with_silverfast_8.shtml
Larry Heath
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« Reply #1230 on: January 21, 2013, 10:00:11 PM »
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http://zczy.en.alibaba.com/productgrouplist-214342460/Clean_fluid.html

Red and clear cleaning fluid source. Along with a bunch of other Epson parts as well.

The decryption cards look like a cool bit of something.
« Last Edit: January 21, 2013, 10:02:58 PM by Larry Heath » Logged
davidh202
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« Reply #1231 on: January 21, 2013, 10:24:06 PM »
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You must have missed this one by me ...
http://www.luminous-landscape.com/forum/index.php?topic=61585.msg586703#msg586703  The pigments do indeed settle after a couple of months.
Removing the carts too mant times to shake them is a no no according to the manual, as you can ruin the cart seal, which will then allow air into the lines ...
and we are pretty sure that is not a good thing! Wink

David
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kdphotography
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« Reply #1232 on: January 21, 2013, 10:57:58 PM »
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As silly as it sounds (I know I thought it was crazy at first), unlock the wheels to the printer stand and gently roll the printer back and forth to agitate the ink cartridges.  Switch sides and repeat.  This avoids ruining the seals on the cartridges by repeated removal/insertion.
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Eric Gulbransen
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« Reply #1233 on: January 21, 2013, 11:07:10 PM »
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Direct my cart shaking post toward the person (can't remember who) who recently suggested a schedule of cart removal and agitation that was simply out of control.   Anyone in that much of a panic over their inks settling, I hope this settles your soul.  Obviously it's smart to agitate, but there is no need to jeopardize your machine over it.  Remarkable stuff this ink is.  


Next discovery revealed - we know what the honeycombs are for.  In fact we know what all the pretty cut-out shapes that surround the flexing chamber wall sections of the piezo board are.  It's called "mechanical adhesion".  Any time you want to glue one thing to another it's best to prep one or both objects by roughing up their surface - to give the glue something to grab onto.  Four minutes after it hit me straight in the forehead again, I took one of the removed printhead faces, flipped it over and examined it's underside.  Yep.  There are traces of clear glue residue all over the underside of the printhead's tin roof, and it's all in the many funky shapes of the piezoboard's honeycomb surface.  Turns out these honeycomb shapes play a critical role in keeping the different inks in our channels from coming together inside the piezoboards.  


All these discoveries are great.  Learned a lot today.  But still not what really matters...

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Blue moon
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« Reply #1234 on: January 22, 2013, 06:51:22 AM »
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So anyone paranoid about their inks separating and settling in the carts, or their lines, or their dampers, like the muck you need to shake from the bottom of an Odwalla protein drink, I think it's safe to say rest easy.  I don't know what Epson makes this ink out of, but that's impressive.

Actually
I am the culprit who is paranoid about agitation......guilty my Lord....

Bear with me please for going back over old ground but as we all know,the basic makup of ink is just 3 things
Pigment......to paint with
Resin......to stick your paint on to something like paper
Emulsifier....to make the pigment and resin cooperate as they would normally  like to go their separate ways...

And water of course is there in abundance too...NO AIR IS DESIREABLE UNTIL THE INK LEAVES THE NOZZLE..a printer in theory should behave no differently to an ink cartridge....

Agitation is the way that the emulsifier gets to bring the pigment and resin together...
But its a subtle problem.....you should not of course expect to see sludge too often....nor would i expect to see anything in the innards of a dissected cartridge (which i have done several times too )simply because one has to agitate the cart to get it opened...
Nor would i recommend pulling carts out to agitate...(i have constantly advised against doing this since i joined this thread..)..its so important .....you will wear down air seals and more importantly you stand a good chance  of destroying the cartridge chip sensor in the printer which requires a technician to fix unless you are prepared literally to pull the machine apart yourself ... I had to do that twice...
All that needs doing is GENTLY AND BRIEFLY rock the printer on its loosened wheels...maybe 1 second gentle touch ...in my case one printer had to be placed on a shelf so i made a simple timber base on wheels..put the printer on this base...simple stuff...
Other printer manufacturers have automatic agitation programs built in to the printer and in my humble opinion its for no other reason than to give the emulsifier a chance to keep on top of pigment and resin components drifting apart....my next printer will not be agitated by me...it will have inbuilt agitation ...for sure..
Mark and I have focussed on the servicing needs of 800 and 900
I have been agitating in a programmed way for 75 days (with the previous 210 days as backup experience )with 5 auto checks at 15 day intervals ...4 of the autos were clear first time ...the bad one required 10 minutes time to clear.....no printing (2 a4s)...just stress testing..i never had that clog free pleasure in the previous 6 years of ownership of that printer....
Mark achieved the same result on the 900 by printing 25 prints.....and he knows his printer intimitely...top class management and discipline.......in my case ,a few seconds daily has saved me piles of time and money on cleaning chores..Yes you are thinking that the 800 and 900 are completely different printers ..they cant be compared.....but didnt Epson tell you that the 900 would be smarter and clogs would virtually be consigned to the history books..

BUT BUT
I may be wrong...and i need to know that i am wrong....

SO

TO DISPROVE my agitation theories and consequent paranoia ,i will now do a 75 day test with 5 autos AND NO GENTLE PRINTER AGITATION during this test period ....with zero printing of course...the only factors left in the equation this time will be  TURN ON every day and epson k3 inks as usual....i should in theory come back with the same auto results (80% Autos clear first time or even 100% clear first time..) that would then indicate that autos without agitation is at least as efficient or more efficient than autos with agitation....
Will let you know auto results after each 15 day interval so  that the 75 days doesnt feel too long...
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davidh202
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« Reply #1235 on: January 22, 2013, 09:50:59 AM »
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Doesn't anyone believe that the Epson design engineers would have thought that one out if it is so necessary to agitate the inks?
I think the simple act of turning on the machine, which pressurizes the carts, is enough to agitate the ink in the carts!
The ony recommendation from Epson is to use the carts up within 6 months of opening, and that probably has more to do with the carrier slowly evaporating and the pigment thickening,which is probably not a good thing.

David
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Eric Gulbransen
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« Reply #1236 on: January 22, 2013, 10:00:40 AM »
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Last discovery before work - I took Alan's Glycerol mixed with distilled water and spread out a 6x6 puddle of it on the counter, in the sun.  Next to it I spread out a 6x6 puddle of water.  Two days later Alan's puddle is still wet.  The water's been gone since 30 minutes in.  My next experiment will be filling a spray bottle with this solution and spraying over the capping station before putting this 7900 to sleep for a week.  I wonder if there will be a difference in clogs..
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Alan Goldhammer
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« Reply #1237 on: January 22, 2013, 12:44:01 PM »
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Doesn't anyone believe that the Epson design engineers would have thought that one out if it is so necessary to agitate the inks?
I think the simple act of turning on the machine, which pressurizes the carts, is enough to agitate the ink in the carts!
The ony recommendation from Epson is to use the carts up within 6 months of opening, and that probably has more to do with the carrier slowly evaporating and the pigment thickening,which is probably not a good thing.

David
Doubtful.  the ink is contained within a collapsible bag within the hard plastic shell.  It's the only way that ink can flow.  A hard bottle won't work as the sides don't contract and a vacuum would form preventing ink flow.  Nothing should evaporate from an unopened cartridge (same reason why soda doesn't evaporate from an unopened container).

Alan
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Ernst Dinkla
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« Reply #1238 on: January 22, 2013, 12:48:33 PM »
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Doesn't anyone believe that the Epson design engineers would have thought that one out if it is so necessary to agitate the inks?
I think the simple act of turning on the machine, which pressurizes the carts, is enough to agitate the ink in the carts!
The ony recommendation from Epson is to use the carts up within 6 months of opening, and that probably has more to do with the carrier slowly evaporating and the pigment thickening,which is probably not a good thing.

David

Keeping the pigment particles in suspension requires delicate formulations of the ink ingredients, the particle encapsulation, its polarity etc. Test involves storing the ink at higher temperatures, centrifuges etc. And yes I have seen yellow inks settle too.

The Epson ink pressure system is very passive on the ink content in the carts. The carts empty from the side of the cart too which does not create much flow in the cart either. HP carts empty at the bottom, the regular membrane pump activity there stirrs the ink at the right spot.

What Epson engineers should have thought about is open for discussion
and there will be patents they have to consider.

Ernst, op de lei getypt.
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chaddro
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« Reply #1239 on: January 22, 2013, 03:17:45 PM »
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http://zczy.en.alibaba.com/productgrouplist-214342460/Clean_fluid.html

Red and clear cleaning fluid source. Along with a bunch of other Epson parts as well.

The decryption cards look like a cool bit of something.

Larry,

I contacted this seller, and this is his response:

Product Name:Epson Original printhead clean liquid.
Volum:1000 ml
Unit price:45.00 usd/1000ml.
Color:Red/White.
Quantity:2pcs (1pcs white/1 pcs red).
Total Weight:2.5KGS
Shippment fee:60.00 usd by EMS. (5-7 days will arrive your hand).
Total amount:150.00 usd.
 
We haven't MSDS at head for these liquid.All of them are Original.Made in Japan
Epson company.
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