HP 364 losing color at end of print

[akuarela]

Hi fellow HP'ers, I'm having an issue with my HP 365, that I did not have before since my 26500 (which was the main reason we had to change over).

So, since this is a material I use very frequently (Substance 2755 gloss), I did a few tweaks per HP instructions such as increase the optimizer 24%, a couple of cleans, etc. All this didn't seem to make a difference with this issue. In the green circle it is more noticeable, something like whitish bands going to the edge.

Any ideas?

Thank you!

 

[balstestrat]

At least one of the printheads is underperforming. When were they installed and how much usage is on them?
Is that overspray magenta/black/cyan?

A momentary workaround what you can do is add spit bars from your RIP. That should help some until you get new heads.
And take down the optimizer to ~15%, it's probably not doing much over that.

You can also print UNI-dir if you want to keep it as sharp as possible. But it will be as slow as 16p so not for "high speed" production.

 

[akuarela]

Appreciate this balstestrat. The printheads are not the newest, they were installed on mid 2019, except for one, the ones with most usage are at about 3500.
Since my post, I went ahead and did some scary maneuvers that seemed to have solved the issue:
1) took each printhead out and gently wiped with (supposed to be distilled) bottled water with my non-lint polyester cloths (the type used to clean UV printers, totally flat jersey)
careful to not reuse any dirty area
2) took some foam swabs and then also with the water, proceeded to clean the gunk around the bottom of the hole where each printhead sits
3) after closing the printhead compartment, and after it moved to its resting position, I opened the cover to wipe up the gunk that had fallen on the media, BEFORE it started doing all its calibrations, etc. Sure don't want any of that back on the printheads.

My new test printed fine, but will sure keep the rest of your instructions on hand in case we run into this again. Of course I know that will have to replace those printheads in the near present/future...

#cleanprinthead #gunk

 

[balstestrat]

Yeah you will most likely see this when the printheads heat up as you print a longer job or multiple jobs.

You can try to figure out which one of them it is if you don't want to change them all. Or if you end up replacing most, maybe you can leave out the old optimizer. Its usually good.

2 year old heads anyways, time to replace. You have such a low usage that the internal filters can start to clog.

And with low usage, start a habit of monthly taking out the cartridges and shaking them. You can avoid some issues.

 

[akuarela]

Thanks, had not seen that tip about shaking the cartridges.