LM/LC Printhead Burnout

This is more of a PSA than anything for the Latex 365, but this has been about 6 months of issues, workarounds, and tons of money wasted with a workaround that seemed a bit ridiculous.

Back around August 2020, we were running a job that had to print 4 sets of vinyl wall covering, roughly 750sqft each, of a solid medium grey color to match a paint sample and had some orange and darker grey text to break up the medium grey. All went fine of course during samples and testing, but when I start printing the full job, things start to go really awry. This is when the first LM/LC print head was replaced. I had a fade out/fade in dropout during the first few panels that I knew usually meant the printhead needed to be replaced so I did. (IMG_0937) Printed them all, but then I noticed when I was QC the panels while laminating, there was 2 thin lines that were being dropped out by the LM. (IMG_1221) So thought that was strange, reprinted the panel, thus begins the color consistency issues.

This grey color would not under any circumstances color match consistently unless they were all printed at once and even then, there was a gradient color shift from the first panel to the last panel. And the bad part, I kept having major issues with the LM/LC print head so essentially after rejecting about 2 of the sets (nearly 180ft of vinyl/laminate in the garbage) ended up having to replace the LM/LC printhead every time I needed to print it and even then after printing about 30-40ft, I'd get the same thin line dropout as you see in IMG_1221. After going back and forth with HP support for probably a good 2 weeks, having them come out and replace everything from the ink cartridge to the main board on the carriage, I was still having this same failure with new LM/LC printheads trying to print this job. Whoever I was talking to with support wouldn't cover the printhead with the warranty because it was still "within an acceptable range" of nozzle dropouts. He also didn't want to see any of the pics I posted, so there's that too. IMG_1290 was what one of the LM/LC printheads was doing after printing just 2 of the sets. I had used every single resource at my disposal, to no solution other than to keep replacing the printhead. Made a tiling profile, spit bars on, OMAS off, TUR hooked up before printing, slowed it to 16p, got it all set up every time per Timothy's video with resetting the color calibration and running that before I started printing.

So, come to December, had to go back on site, tear everything off 2 of the walls, replace them due to the color inconsistency (even after spotting the color issues, the installer still continued to put them up) with the new installer putting them up, all went well except he managed to wreck one of the panels. So had to reprint one whole entire wall again because the color wouldn't ever match again. Went through the same process, bought a new printhead, had of course another dropout in the 4th panel (didn't end up needing to reprint it because it was going to be hidden by an image panel) and installed it not long after. Well, when he installed it, the installer screwed up the panel order because he didn't pay attention to the order/quantity. So once again, went through the whole ordeal and by this point, I was just fed up with trying to print this consistently as by this point, even after resetting the color calibrations after replacing the printhead, the grey ended up being a green hue and looked terrible even with some slight color correction to try and fix it. So I didn't replace the LM/LC print head, and had even worse print failures and I rejected the entire set again with multiple failures of the printhead on panels 2 and 3, plus the green hue color. This job by the way took roughly 8 hours to print a full set due to the tiling mode and pass settings so having someone sit there to watch it wouldn't have been worth it at all.

So this very last time since this was the very last thing I hadn't done, I started back from scratch. Turned off the LM/LC with a new tiling profile with a rebuilt ICC profile, made up a new CMYK mix in the art file to get off of the paint color mix, printed a couple samples to get it back to the original samples we made way back in August. Printed one sample, came back over the weekend printed it again and lo and behold, by turning off the LM/LC printhead, I had zero color issues and it matched perfectly even days apart and not even redoing the color calibration. I then printed the full set and all 9 panels were the same color with zero dropouts, banding etc. Resolution was a bit lower since it was only the regular CM to get that same grey color, but it's just a ridiculous workaround to finally get consistent printing with this printer.

And of course last week, the HP Latex 700 and 800 were announced and now has a pair of LM/LC printheads that would probably fix all of this, but not exactly like we're in a position to buy a new $20K printer.

So long story short, do not print long-runs of grey or any heavy LC/LM colors with this printer unless you turn off the LM/LC printhead otherwise you'll end up with the same issues I had.

Hello. I am having the same issues and would like to turn off the Light Magenta and the Light Cyan and see if that fixes the issue. I can't seem to figure out how to do this. I am using a profile from HP for their PVC free wallpaper. Is it not possible to edit and existing profile? The option to change the color is grayed out. I am not really sure how to create one totally from scratch. Did you find any directions online how to do this? If so, would you share? Thanks

#2 To turn off the LM/LC, you have to make a new print mode for the substrate you're working with. When you create the new mode, in the screen where you pick the number of passes and ink saturation, I believe there is an button in the bottom right that says "Advanced Settings" that if you scroll down to the bottom, you'll see a drop down option to pick to print with CMYKcm or CMYK. You can only change this with creating a new print mode by the way.

Then once you do make the print mode, run color calibration and make a new ICC profile and you should be all set.

Thanks. It is grayed out on editing one. And from the substrate screen it won't let me create a new print mode. I am not finding any other place to create a print mode. Any idea how to turn it on so it can be edited? Can't seem to find much online about it. I put a picture of it grayed out. Is yours editable from this screen? It is an HP profile for the PVC-Free Wallpaper.

I found it and got it changed. I am hoping I am good now with all the extra changes to do long panels with a lot of solid colors.

I do have one more question you may know an easy answer to. I have 72 linear feet that printed okay, but it was prior to shaking up the inks and doing extra color calibrations beyond what the printer asks for. I calibrated after I had to replace the LM ink and now it is printing the same colors. Do you have any idea how I can try and actually match how it printed the colors before? It is only 2 PMS colors. I have a NIX color sensor and I did a reading of it, but neither the CMYK or the RGB mix match it when printed . They print with a lot more magenta in them. It is pretty expensive media that is why I would like to march if at all possible. And it would be good to know for future if there is a way to create a match to a color. I am using Flexi with the HP 365.

Hello,

My suggestion is to change the inks. These color consistency issues can be caused by the ink itself and an ink change should solve these problems.

To prevent the printer from printing without using the LC/LM PHs, a solution/workaround is to effectively prepare the file by creating it with CMYK colors.

If changing inks and the CMYK printing does not solve the issue, I suggest contacting your support representative for further analysis.