Z6100: Light Magenta is coming out lavender

[Steenland]

Printer: HP 60" Z6100ps. I noticed my prints were starting to go slightly green, so I ran a color calibration and noticed the Light Magenta patches were printing as a lovely shade of lavender or light purple. Diagnostic print confirms it: the patch that should be pure Light Magenta is now light purple.

Since, on this printer, Light Magenta shares a printhead with Light Cyan, I assume the LC is contaminating the LM to create the light purple. So it must be a failed printhead, right? However, there are two LM/LC printheads, and they are BOTH producing light purple instead of LM. But not identical hues. #3 is worse than #4, but both are definitely contaminated. The contamination appears to be upstream from the nozzles, since the individual nozzles are all firing the same hue.

Both LM/LC printheads are "out of warranty," but aside from the hue problem, there are no virtually no faulty nozzles.

While I wait for a new pair of printheads to arrive, I thought I'd check with the group to see if anyone else has seen this. A Google search turned up a couple instances of this on a variety of printers (not just HP), but none of them posted the solution.

 

[Deleted member 16349]

Printer: HP 60" Z6100ps. I noticed my prints were starting to go slightly green, so I ran a color calibration and noticed the Light Magenta patches were printing as a lovely shade of lavender or light purple. Diagnostic print confirms it: the patch that should be pure Light Magenta is now light purple.

Since, on this printer, Light Magenta shares a printhead with Light Cyan, I assume the LC is contaminating the LM to create the light purple. So it must be a failed printhead, right? However, there are two LM/LC printheads, and they are BOTH producing light purple instead of LM. But not identical hues. #3 is worse than #4, but both are definitely contaminated. The contamination appears to be upstream from the nozzles, since the individual nozzles are all firing the same hue.

Both LM/LC printheads are "out of warranty," but aside from the hue problem, there are no virtually no faulty nozzles.

While I wait for a new pair of printheads to arrive, I thought I'd check with the group to see if anyone else has seen this. A Google search turned up a couple instances of this on a variety of printers (not just HP), but none of them posted the solution.

Sounds similar to a problem I had on my old home printer. It was very strange but what happened was that the ink in the cartridge got contaminated. Instead of printing a nice yellow, it printed an orange. Some how the ink from another colour got sucked back up into the cartridge. This happened with a less costly replacement cartridge.

I think the problem was not in the heads since when I went back to the original cartridge, the problem did not happen. I also think it is related to when the head sits in a stationary position or when cleaning, the ink goes to a pad and there might have been the chance that the inks on that pad would get sucked back up through the head and back into the cheap cartridge.

I am guessing that there was some difference in how the good cartridges vented when compared to the cheap ones.

Maybe this is related to your problem. Maybe your function that collects ink when cleaning needs to be looked at or the venting of the ink supply. Just a guess.

 

[Steenland]

Thanks Erik. Interesting possibility. Perhaps the fact that my Light Magenta cartridge is almost depleted (below 50ml) has something to do with it. Maybe there's a bit of back-draw in the near-empty bag? That might explain why the problem is occurring with both LM/LC printheads, yet inconsistently. Perhaps someone who knows more about the inner workings of the Z6100 could tell us whether this is technically feasible.

I have a new LM print cartridge arriving tomorrow, so we'll see if that helps.

Further info, for anyone else picking up this thread: I'm using all genuine HP printheads and ink cartridges. The #3 LM/LC printhead has fired 1984 mL, and the #4 LM/LC printhead has fired 2066 mL. Both are beyond HP's warranty limit of 1200 mL, but it's standard for most users to get at least two or three times that I believe. (It's certainly been my experience.) And as I mentioned, nearly all of the 2048 nozzles on each printhead are firing cleanly and accurately (aside from the color issue).

 

[Steenland]

The problem was definitely related to the ink cartridge and NOT the printheads. When I replaced the Light Magenta cartridge with a new one, the problem cleared up after a few prints. Has anyone else seen this on a Designjet?