Need Help horizontal banding in blue colors only (L26500)

[bigben]

So, I have a HP L26500 and I have horizontal banding in blue color only. I normally have this problem in black color, but now it's fine. I've changed both cyan printhead tried different material and profile and I still have the problem. I have printed the ''test'' print and everything is fine. I also made a printhead alignment even if it was already done after the changing of the printheads.

What should I look for or test next? Thanks.

 

[bigben]

I've forgot to mention, if I print a cyan, magenta, yellow and black square (12inX12in), everyting is fine.

 

[flyplainsdrifta]

pics?

 

[bigben]

pics?

sure

 

[bigben]

if it help, I've printed this at 10pass.

 

[Bly]

I guess you've looked under the heads to see if there's a stray bit of paper dragging.

 

[flyplainsdrifta]

when was your last cyan cartridge change? I've seen that on my 25500 years ago on an expired cart that I missed. you can try doing a sub advance check. also did this just start on this run or was it progressive?

 

[bigben]

I guess you've looked under the heads to see if there's a stray bit of paper dragging.

I've just took off the two cyan printhead to interchange them. When I've oppened the main door, I've saw small part that was looking like a small rock of ink (around 2mm X 2mm) near the carriage. I've also cleaned the printhead connector and look if there was any debrit. Now the printer is performing a alignment. Also, when I've changed the two cyan head, I've notice that the printer performed a printhead cleaning cycle. Now, it did not do it.

when was your last cyan cartridge change? I've seen that on my 25500 years ago on an expired cart that I missed. you can try doing a sub advance check. also did this just start on this run or was it progressive?

Thanks for the suggestion, but the cartridge is under warranty and less than 2 months old.

 

[bigben]

Just made a test, and nothing changed.

 

[MikePro]

maybe ink starvation during fast print speeds? do you get the same result with 16pass?
maybe a gunked-up maintenance kit? that ink drain funnel / wiper can get gunked up faster than the maintenance kit runs out. on that note, have you changed your waste ink line & container recently? if it fills-up, it can inhibit drainage and gunk up that funnel/wiper as well.

what does your test print look like? big fan of the one via the clean printheads menu, as you can see the individual nozzle-lines.

 

[bigben]

maybe ink starvation during fast print speeds? do you get the same result with 16pass?
maybe a gunked-up maintenance kit? that ink drain funnel / wiper can get gunked up faster than the maintenance kit runs out. on that note, have you changed your waste ink line & container recently? if it fills-up, it can inhibit drainage and gunk up that funnel/wiper as well.

what does your test print look like? big fan of the one via the clean printheads menu, as you can see the individual nozzle-lines.

I have to say I did not try other pass than 10. So, the printhead cleaning kit have been changed this monday (with the ink funnel, filter and bucket) . the maintenance kit is at 68% right now. As for the test print, here are the picutes.

One this I just remember, I know something fell off the printer this week and grab the cyan lever and disconnected the cartridge while the printer was off. The printer immediately power on and ask for the cyan cartridge to be hook up. So right now, I've used the panel to reload the cartridge. Maybe there was air or a wrong pressure?

But again, when I print a full cyan square (12inX12in) everything is fine.

 

[MikePro]

you're looking at the cyan, but your banded image certainly has magenta in the mix. what does a 10pass magenta box look like?

edited to add: your cyan cartridge should be fine despite accidentally depressurizing the system, as the system will keep prompting you to install ink cartridge if otherwise.

 

[MikePro]

i do sometimes get slight banding on 10pass, which is why I rarely run it. 16pass fulltime, unless i'm in a rush and I dial it up to 12pass. I have a feeling those knocks in your magenta nozzle test might be the culprit. higher-pass rates fill-in deflected nozzles better, although the color might not be as true as a 100% nozzle test patter.

 

[bigben]

you're looking at the cyan, but your banded image certainly has magenta in the mix. what does a 10pass magenta box look like?

edited to add: your cyan cartridge should be fine despite accidentally depressurizing the system, as the system will keep prompting you to install ink cartridge if otherwise.

at 10 pass, everything is fine if I print four 12inX12in squares (CMYK). I saw some minor banding in the black, but I have to look at it on a certain angle with certain light. But the 3 other colors are perfect. The print test is very good also

i do sometimes get slight banding on 10pass, which is why I rarely run it. 16pass fulltime, unless i'm in a rush and I dial it up to 12pass. I have a feeling those knocks in your magenta nozzle test might be the culprit. higher-pass rates fill-in deflected nozzles better, although the color might not be as true as a 100% nozzle test patter.

I've always printed at 10 pass for everything except backlit and never had a problem so far.

I've just changed the ink maintenance kit and that thing was nasty compared to the ones I've changed in the past. If I print on cheap poster paper, I have very small banding. If I go on the vinyl, the distance between the banding have shortened and are less visible, but still there. If I print a black and white image that I would normally have problems with it, everything is perfect. If I print a regular photo, everyting is good. It's just that particular blue image that give me trouble.

 

[Bly]

Is it happening on all media or just one?

 

[papabud]

It's just that particular blue image that give me trouble.

is there some kind of texture in the back ground of that file that might look like its banding

 

[bigben]

Is it happening on all media or just one?

on all media, but on cheap poster paper is a bit less visible. But like I said, after changing the ink maintenance kit, there still have banding but they are thinner now.

is there some kind of texture in the back ground of that file that might look like its banding

no texture. It's a gradient, but the lines would be at 45 degree if it was the gradient. If only I had another printer, I would test it to know if it's the file that is the problem.

 

[papabud]

can you rotate your file 90 degrees and see if it changes

 

[bigben]

can you rotate your file 90 degrees and see if it changes

I've tried it and I still have horizontal banding.

 

[papabud]

your machine has a light cyan head, hows that one look