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EFI H1625 White Ink Trailing

cnolder01

New Member
Hey, so we have an EFI H1625 that runs pretty well most of the time. My latest issue is that the white ink seems to be leaving a trail after each character it prints. We had this issue once, and it stopped on its own. Now it's consistently doing it. I have tried increasing the negative pressure, ran a purge and sweep and checked that all of our ink is up to date and in good shape. I'm not sure what else to try. I appreciate any insight, thanks!
 

Superior_Adam

New Member
We got rid of the 1625 thankfully. We now run the 16H. My guess without seeing a picture would be the white ink leaving a tail would be a static issue.
 

greysquirrel

New Member
Is there a valve near the waste ink tank? I know with a HP FB series flatbed, if that valve s open it creates a stronger vacuum than the printer creates at the heads and will cause this to happen...usually with outermost heads on the carriage...so if someone recently emptied ink, they may not have closed the waste valve all of the way.
 

Michael-Nola

I print things. It is very exciting.
The HP FB's are fairly unique to that problem by design. Fortunately the 1625/16H build are not configured remotely the same. Not to sound like a broken record lol, but a few pictures would tell us a lot more. White is tricky in this case due to the nature of the ink and the practical use of it by most shops. It may be in date, but how old is it? That line of white ink works very well when it's young, but it separates and ages terribly. You really have to use that stuff for it to behave at it's best. You said the trail comes after text, so it sounds like you're printing text in white or backing with it? Unless it's LARGE text, then you're asking white ink technology to perform in it's better categories - your'e not asking for junk work.

Before moving vacuum pressure out of spec or looking for machine/head issues, here would be my troubleshooting steps I most commonly find as the culprit in shops with various equipment:
1. Most people always run an unlinearized white output at 100%, this is a common mistake. White has several issues at physical 100% output - droplet size mostly, then curing, adhesion, interlinking, cracking, etc. White reflectance opacity is achieved on most printers at 15-20%. Transmission opacity starts at 50%. If you need 100% dump opacity, then 2 hits of 50% will look better than 1 hit of 100%. (So run 3 layers, instead of 2). If you calibrated for linearized white (which I wouldn't recommend unless you know you need it), then none of that applies to your application.
-----Solution Test: Run Color over 50% white, see if the problem remains. Then Color over 75% white.
-----Try Grayscale just for kicks. White opacity drops dramatically by nature. Usually a much better laydown. May not be as opaque as you require depending on your application.
2. If the ink is older than 3 months, swap it out with a NEW bottle (not 6 months old but unopen!).
-----Solution Test: With new ink, do 3 full secondary tank dumps then purge/wipe and start testing. If the ink is older than 6 months, it is absolutely in the "misbehave" category in my book. Yes it will work technically, but over 6 months old in that configuration and many of those printers cannot lay it down clean for fine text.

Start there and let me know, I'll be happy to help further. Running a more appropriate droplet size and pass/output amount on that ink will do wonders, and newer ink on top of it. White is a technology that OEM's have not done a great job of educating us about. Even if you get it looking good off the press, if you dump 100% pass backers for decals and stick them out in the sun, they will often crack in just a few months on an inelastic substrate. And remember that if your end product ends up on an opaque backer of any color, you never need 100% white, just enough to provide a whitepoint while the underlying object creates opacity.
 

tbaker

New Member
Try this to clear up white drip problems, raise the negative pressure to -3.9, allow the press to sit for a couple minutes (3-5) and then set it back to normal range.

like several have said a picture is worth a thousand words. But the above will help this platform when things like this happen. Also check your nozzles, if you have a significant number clogged, the jet could be over pressuring internally, causing erratic cast.
 
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