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Author Topic: "Cold start" colors  (Read 2980 times)
Enrico PA
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« on: January 29, 2009, 07:34:50 AM »
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Hi,
I've just joined this discussion group, and I have a question regarding the new Epson 7900 inkjet plotter.

I think one of the main issues of pigment printers is the "cold start" print quality, due to the altered pigment dilution in the ink base.

In other words, is there a color shift after 1 day of stop? And after more days? And after 1 month ?
And, more important, how many prints and/or nozzle clean cycles we need to restore the initial printer characterization ?

Unfortunately I've always seen not-so-good response from Epson x800 printers, while I have good reports from Canon ipF6100/8100 owners (also thank to the Canon's auto-shaking carts).

Has someone tested this property on the 7900/9900 ?

Thank you !!

Enrico
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AlanG
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« Reply #1 on: January 29, 2009, 09:40:14 AM »
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I am not sure what you are getting at. Do you think the pigment settles? I have an Epson 7600 and it seems to print consistently even after sitting. I now have a Canon ipf6100 and note that it occasionally agitates the ink which sits in reservoirs.  It doesn't actually shake the carts.
« Last Edit: January 29, 2009, 09:41:13 AM by AlanG » Logged

Alan Goldstein
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Enrico PA
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« Reply #2 on: January 29, 2009, 10:50:37 AM »
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Quote from: AlanG
I am not sure what you are getting at. Do you think the pigment settles? I have an Epson 7600 and it seems to print consistently even after sitting. I now have a Canon ipf6100 and note that it occasionally agitates the ink which sits in reservoirs.  It doesn't actually shake the carts.

Thank you Alan.
Yes, I'm referring to pigment settling.

This happens not only in the carts, but in my opinion also in the ink-pipes and probably in the heads.

I see color shifts on Epson4800, in particular when printing images containing BW (or near-BW) areas.
After some days of printer stop, the prints have initially a magenta cast, then it changes to a green cast, and after some prints it gradually return to initial gray tones.
Probably this happens because of the settling of pigments (magenta ink?), followed by ink with lower pigment density.

(Obviously I always print using fresh ICC profiles)

Regarding the ipf6100,  yes it has an ink auto-shacking system inside the reservoirs (cartridges).
Epson 7900/9900 has a pressurized ink system, but I don't know if this can help to solve the pigment settling issue.
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AlanG
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« Reply #3 on: January 29, 2009, 01:22:57 PM »
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Quote from: Enrico PA
Regarding the ipf6100,  yes it has an ink auto-shacking system inside the reservoirs (cartridges).
Epson 7900/9900 has a pressurized ink system, but I don't know if this can help to solve the pigment settling issue.

Perhaps I was not so critical with the 7600 and rarely printed b/w on it.  I'm trying to sell it since I got the 6100. I guess we are talking about the same thing but I understood that the way the Canon works is that it drains some of the ink from the carts into a reservoir. This was to enable it to keep printing for a while while changing a cartridge.  I didn't know how it agitates, but shaking the carts may be how it does this.  They seem to be mounted in a way to allow some movement.
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Alan Goldstein
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Enrico PA
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« Reply #4 on: January 31, 2009, 06:21:50 AM »
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Quote from: AlanG
I guess we are talking about the same thing but I understood that the way the Canon works is that it drains some of the ink from the carts into a reservoir. This was to enable it to keep printing for a while while changing a cartridge.  I didn't know how it agitates, but shaking the carts may be how it does this.  They seem to be mounted in a way to allow some movement.

Thank you Alan.
Yes, probably Canon does ink shaking into the reservoir, and probably in the carts, or both. This should assure a constant degree of pigment dilution in the ink base.

It isn't clear if also new Epsons 7900/9900 have solved the pigment settle problem.
Also better ICC profiles are not valid if printer shift colors each time we switch-on it.

Checking this issue is very simple: it is sufficient to print a very simple 21-step-gray target (the QuadToneRip one) on the same paper, each time the printer is switched on. A simple spot-reading done with a spectrophotometer (or suitable colorimeter) is sufficient to compare results over time.

In my opinion for fine-art photographers this is a very-very important feature, surely most important than a +5% gamut volume or +10% print speed !!!  
« Last Edit: January 31, 2009, 06:22:49 AM by Enrico PA » Logged
Bob Smith
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« Reply #5 on: January 31, 2009, 07:38:42 AM »
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Quote from: Enrico PA
It isn't clear if also new Epsons 7900/9900 have solved the pigment settle problem.

I can't see where there's a problem to solve.  I confess I've never done readings to compare color from a freshly started printer versus one that's been running for a while... because I've never seen a need to and this is the first I've ever heard someone even bring up the idea.  Considering all the wide format printing related forums I've monitored, it clearly must not be an issue that affects many (any?) users.  My experience is with a 4000, 9600 and 9800.  I print color and bw work.  QTR on the 4000 and 9600.  ABW on the 9800.  Considering how much dancing around the heads and lines do while the printer goes through its normal priming cycle and media sensing before it actually starts delivering ink to paper I can't imagine that settling could possibly be a problem there.

Bob Smith
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Enrico PA
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« Reply #6 on: January 31, 2009, 03:35:05 PM »
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In all Epson's user manuals there is one recommendation: "shake the ink cartridge well before installing it, for best results".
This operation helps to restore the correct dilution of pigments in the cart.
But... what happens when the cartridge is FIXED on printer for a day, a week, a month, without shaking it ?

Canon for the first time has introduced a system that mix the ink by shaking it (into the carts and/or into the reservoir).
Well, I think there was a REAL problem with LUCIA pigments concentration into the inks !

So Bob,
I don't want to deny your experiences, but believe me there are many users I know that complains about color stability of pigment plotters.

All I ask to 7900/9900 owners is to do some tests (I repeat: very fast and simple!) to verify this (sure? potential?) issue.
Only this!  
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Bob Smith
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« Reply #7 on: January 31, 2009, 05:58:14 PM »
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Quote from: Enrico PA
But... what happens when the cartridge is FIXED on printer for a day, a week, a month, without shaking it ?

When a cartridge is fixed for long period of time, yes it may need to be removed and gently shaken.  I would say long means multiple months with no use of the printer at all.  Any use of the printer at all vibrates the carts enough to keep pigment in the carts suspended.  That's very different than your worry that a printer sitting for a few days/weeks without printing is going to suffer from settling in the lines/heads.  That isn't going to happen.
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Enrico PA
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« Reply #8 on: February 02, 2009, 04:18:52 AM »
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Quote from: Bob Smith
When a cartridge is fixed for long period of time, yes it may need to be removed and gently shaken.

Well,
you agree about pigment settle problem in carts !
Yes, on x800 printers you can remove carts and gently shake it (every week - every month - every year?) but you have to admit that the Canon ipF approach is much more serious and effective.
(on x900 printers you can remove carts but there is some ink waste when you plug them on the printer, as stated in x900 user manuals).

This said,
I think the problem of pigment settling is possible also in other vertical sections of ink circuit, such as printer heads. I think that some auto-cleaning cycles are made for purging potential stettled ink, instead of head cloggings. Yes, I suppose it, I'm not sure.

My interest is to know if ALL potential problems of pigment ink are under control in new Epson's plotter line, without any user intervention.
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Wayne Fox
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« Reply #9 on: February 02, 2009, 03:48:45 PM »
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If you are seeing this in your 4800, I think your printer might have a problem.

I have never noticed this with any printer, going back to the 9600 I started with.

Settling in cartridges takes a substantial amount of time .. it's not like sand suspended in water.   I doubt very much that even when settled it's like a mass of solid pigment which would require somewhat violent shaking to re-suspend the pigments ... a gentle motion back and forth is all that is required.  Whatever minor settling might happen in the lines should easily be resolved by the flowing of ink.

No I have never measured it, because I have never seen any sign of this at all.  Even a printer that sits for a substantial amount of time where this may be an issue would most likely require a(several) cleaning cycle(s).  With that much ink moving through the lines more rapidly than normal it seems any sign of this would be resolved as well.
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