Epson Ink Variances?

[iColor]

Greetings!
I thought I should post this and get some input from the forum community as I've been told by Epson that I'm the only person with this issue.
We have an Epson 7880 that we purchased 6 months ago, and I can't mantain this thing in gray balance to save my life. After calibrating the device to G7® method, I would notice a color shift after a couple of days. At first I was blaming the rip (ColorGate) but after careful evaluation I noticed that the drift happened one to two days after empty ink cartridges were replaced with full ones. What I noticed were variations in ink density, particularly the Cyan ink. Epson tells me that the variance between ink cartridges is less than visible, I asked for a delta E spec but they could not provide me with one. The delta variances I get on my gray patches range from 2-5 deltas.
In other words, if my HR patch read .80 delta E to the spec after the initial calibration, it would read 2.8 delta one to two days after an ink cartridge replacement. Is this normal with the UltraChrome K3 inks? Could the printer be causing this problem? I don't seem to have any missing nozzles. It makes no sense that I would have to re-calibrate after every ink cartridge change. The eye is very sensitive to neutral colors and these variations are certainly causing changes in visual appearance.
Any comments or suggestions will be appreciated.

 

[edwinb]

the epson is usually much more stable than that.
are your inks out of date?
are you using good (consistent) media?
is the enviroment the printer is in stable (temperature and humidity)
edwin

 

[iColor]

the epson is usually much more stable than that.
are your inks out of date?
are you using good (consistent) media?
is the enviroment the printer is in stable (temperature and humidity)
edwin

Edwin,
Inks have an expiration date of Oct 2011 and we are using Epson Proofing media. Our film/art department is temperature and humidity controlled.

 

[TerryWyse]

The cyan ink seems to be the most "troublesome" of the Ultrachrome inks as I've run across huge variations in "dark" cyan ink in the past couple of years at a few clients. I ran into it most recently at a customer with an Epson 10600 with a cyan cartridge that was "bad" but that hadn't expired yet. The variation always seems to be cyan ink that appears contaminated with magenta (too blue/purple) and is too dark.

I've no idea whether the cyan ink used today in the x880 printers is the same as what's used in the x600 and x800 Epsons but there's never been any mention of changes in the cyan formulation from one series to the next....as opposed to the changes in the magenta and photo black inks over the years.

I would suggest, rather than tracking gray balance, that you track the solid ink colorimetry on a daily basis. You could use something simple like the IDEAlliance 12647-7 proofing wedge/color bar. Gray balance isn't going to tell you exactly which ink is the problem but measuring the pure primary and secondary inks definitely will. If you have good data tracking, you should be able to take this to Epson and show them the results and get free replacement cartridges any time you notice a shift in the ink colorimetry. Nailing them down to an acceptable delta e tolerance would be nice but probably isn't going to fly. One last thing, make sure you also log the paper colorimetry as well in case they try to blame the media. Paper colorimetry isn't necessarily going to tell you it's a coating problem but it's at least a start.

Regards,
Terry