Print Quality - Color variations coming off straight edges of text and / or tiled jobs

[WRAPIFY]

Wondering if anyone else has ever seen this before?

We have a color tone variation that's only coming off the most square edges of text and / or is aligned perfectly with tiled panels being printed alongside others. The issue's only happening so far on magenta heavy prints. Replacing both Yellow/Magenta print heads with new ones made no difference. Increasing the pass rate seemed to only make the issue more crisp and clear (like it's in the file). The issue's not in the source file though.

The issue seemed to come out of no where (once we started printing this specific color toned art). Tried cleaning the encoder strip (made no difference). We have printed the same magenta heavy art in the past without the issue occurring. We did have an older operating system back then (Windows 7). Now currently at Windows 10. Not sure if it's a printer issue or a RIP software issue. We have not noticed the issue with any other kind of printed art / colors as of yet, and since the issue's not happening with other colors and straight edges  on text / tiled panels (so far), that makes it seem like it's a printer issue and not the RIP software.

To save time and not replace anymore printheads for nothing, wanted to check on here 1st (if anyone has any other ideas).

[skuks]

If you haven't already done so:
- give the cartridges a good shake (to all, not just the magenta ones), usually the color settles out and cartridge must be shaken very well. Result if that's the case will be visible after 20-30 ml of printing)..
- clean the gold contacts on all the heads and the contacts on the carriage itself (some dirt between contacts may cause late start of nozzles), also check the condition of the optimizer heads. Make sure all nozzles on the magenta/yellow head are working (from the browser menu - Display printer information in HP printer Embedded Web Server (EWS)..
- When printing, use a color bar (about 15mm - 0.59in) of both sides of the image or at least from the beginning of the print and observe printed lines for straightness, blur, noise and etc. - meaning if certain printhead isn't working well..

[WRAPIFY]

Hey there Skuks. Thanks for the help. The issue has been resolved after replacing all 5 of the color printheads on the printer at once (and performing a manual printhead alignment + entering the updated values).

We tried most of the initial steps you suggested before replacing all the printheads (shaking all cartridges, cleaned all gold contacts, used a color bar and even on both sides) but with no success. We're not sure if the nozzle count correlates to the symptom seen.

The initial problem description / subject I made should have said "Ghosting" instead of "Color variations" even though the ghosting is a variation of the color tone where the ghosting occurs. Obviously with the fix we found, the printhead(s) were at fault (one or more must have had a problem with the ink load in the specific areas of prints (text and areas with sharp changes in the ink output).

We've been using two HP 360's for 7 years now and have never seen this issue before now (usually the printheads act differently than this when needing replacement). Well, now we know that ghosting is more likely a printhead issue (and not a technician level call). 

[WRAPIFY]

By the way. BOTH of our HP latex 360's were doing this same thing (ghosting on the same exact colors and places). So we're going to replace the color printheads on the other 360 latex printer now as well (and hope the ghosting goes away).

All printheads on both printers were (are) OOW and well over 1,000 mL used (some were at 3,000). We usually run into print quality problems around the 1,000 to 2,000 range and thought we were getting lucky with this round of printheads (on the color printheads precisely, as the optimizer seems to be able to go further without replacement). Not the case.

[skuks]

Just to add about the clogged head nozzles report - when you check the report, there are usually some nozzles out, but the numbers it says are different and inconsistent, which means the heads are OK to print, but may clean them for better performance. However, if it shows a large number of consecutive nozzles (for instance 0,1, 2.. - 200) and not always displays 98:03 error message, it is usually the head that needs to be replaced. I've had a few optimizer and one C/K heads replaced in less than a month of use and it's probably a bad batch... and printer begins to act strange before it shows Too many nozzles out error...