Long print color shift? (L26500)

[struthmuffin]

Hey there,

We recently put in an L26500, and everything is pretty good. We just ran a bit of a lenghtly run of signs, they are a ton of black coverage with some lightly colored text in them. Some of the text is a grey color and as the run went on, the grey started to shift to a blue. Is this normal? Everything else looked perfect. Should we have run less signs at a time? (It was about 2 hours of running at 20pass I believe)

The Light cyan was running very low by the end, but it made it through the run. I would have thought that would have the reverse effect, but maybe that could have been it?...

Wondering if anyone has seen anything like that or knows how to avoid it.
(We are running onyx 10.2 if that matters)


Thanks for any help you can give!

 

[chafro]

Its probable a head stopped firing, could be magenta or light magenta that you are missing.

its normally a sign that the head is about to fail when they stop printing during a run.

 

[struthmuffin]

thanks Chafro, I will check that out or if they seem fine Ill keep a real close eye on them for a bit.

 

[danno]

If you are not running colour bars on the side of the print, it would be recommended. HP informed me the maximum advised run length is 280" - 300" at one time. Even then some colour shift can be expected.

 

[struthmuffin]

If you are not running colour bars on the side of the print, it would be recommended. HP informed me the maximum advised run length is 280" - 300" at one time. Even then some colour shift can be expected.

Oh wow.. thats good to know!! Thanks Danno! I heard about the color bar trick. Id likely just try to keep the prints below that length. Most cases that shouldnt be an issue.

 

[FrankW]

It is a regular problem of thermal inkjets that colours could shift depending on the temperature of the head during long runs. It is one sales argument for the new latex-Printers 300 that they have developped printheads which produces more stable colours.

 

[Christian @ 2CT Media]

We print full rolls all the time without noticing color shifting. We also make sure we swap out low cartridges and save them for later and run the gutter on the left side.

Another good thing to do is turn on the color variance tool as it helps to reduce any color changing during a print.

 

[Ditchmiester]

I've consistently run 800"-1500" at a time on my L26500 and never seen a color shift before. What does running the color bars on the side do to help this issue?

 

[Christian @ 2CT Media]

It keeps all the the heads firing to prevent overheating due to hot Ink build up