Need Help Flatbed UV Ricoh 5Gen Gloss Banding

[Ptzulu]

Hi there!
We have a nobrand (or, Chinese Brand) Flatbed UV 3x2m, KC x2 and MY x2.
Definiton/quality, it’s actually pretty good, no complains whatsoever, other than Gloss Banding.. more noticeable on PVC Foam and high gloss cardboard.. (pictures below)
I’ve tried everything from uno-directional printing, to 4,6,8 pass (don’t have profiles for more, but can make it, although I’m not interested in more pass, since it’s supposed to be production machine, not Uber quality photographic print).
Despite number of passes, gloss banding occurs, marginally difference. Uni-directional vs bidirectional more noticible diference, but doesn’t fix it whatsoever. Printing with only trail/lead UV lights (not LED) does help, but, I think it’s because not curing properly...
Manufactures suggested to tighten X belt, but, even after do that, don’t notice difference... and it’s hard to communicate with Chinese

If you notice, there are some small vertical “corridors” where there is no gloss banding

Any more ideas, besides getting a new machine?

NOTE: red arrow represents X axis print

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[StarSign]

I would say it's the material not the printer

 

[Ptzulu]

I would say it's the material not the printer

It does on most materials, just some are less prone to notice.
Did print some box prototypes, on Metsaboard (about 1mm paper, common on food package) and does the same thing. Also, some times, it does weird banding like ink starvation (example, green splash does some magenta gloss banding weird stuff, but, already ruled out, since tested immediate pauses on those kinda ink starvation and do a nozzle check and all fire.
In that regard, no nozzle clogs on this machine. Ever xD


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[FireSprint.com]

Do you have different feathering modes you could try? In other words, the overlap pattern?

Every printer I have ever had experience with has been able to all but eliminate the gloss banding in 8 pass and/or unidirection mode. It's odd you can't get rid of it at all. (Sorry, not real helpful)

 

[Ptzulu]

Do you have different feathering modes you could try? In other words, the overlap pattern?

Every printer I have ever had experience with has been able to all but eliminate the gloss banding in 8 pass and/or unidirection mode. It's odd you can't get rid of it at all. (Sorry, not real helpful)

I do have overlap settings, called eclosion (super eclosion is the max (like a 80-100% feather).
Does not help

Recommended to use about 70% power for UV lights (traditional, not LED). No help. More power, also no help, less power (like 50 or below) removes banding, but ink is “sticky” to the touch, so not well cured :/

I linearized the profiles when machine arrives, and after about 6 months again. Will try once more just because... I don’t know :/

Any more ideas? Can different waveforms help? Where can I get them? (Chinese support is..... not supportive)


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[chinaski]

If it's happening mostly in dark colors and not the highlights, then that would suggest too much ink is being laid down and your lamps cannot cure fast enough.

You've mentioned linearizing and profiling but what about your ink limits? When I've had gloss banding the culprit is almost always too high of ink limit, especially if you are using less passes and media that isn't as receptive to high ink load.

Do you notice a difference in gloss banding between pure black and rich black?

 

[Pauly]

Clean the encoder strips first.
just looks like it happens in the same spot. this could also be the media.
is the ink completely dry? or tacky?

 

[chinaski]

I'd 2nd the encoder, remembering back to when I had a Chinese printer, the encoder strip and encoder sensor would commonly cause problems and needed to be replaced a couple times over the years. The strip has to be perfectly positioned between the sensor and cannot make contact with either wall of the sensor—both may need to be repositioned.

My Arizona has afforded me the luxury of forgetting about these sorts of problems. Even more frustrating when you realised just how far some of the Chinese printers have skimped on essential components. TANSTAAFL, i guess

 

[Ptzulu]

If it's happening mostly in dark colors and not the highlights, then that would suggest too much ink is being laid down and your lamps cannot cure fast enough.

You've mentioned linearizing and profiling but what about your ink limits? When I've had gloss banding the culprit is almost always too high of ink limit, especially if you are using less passes and media that isn't as receptive to high ink load.

Do you notice a difference in gloss banding between pure black and rich black?

There is a diference between 100% Key or rich black, but I don’t remember what was worst :/
When I say linearize, it’s really in the sense of creating the profile from scratch. I do have and i1 (old one) but it can do the trick.
Or is there another method to limit ink? I use flexiprint as a RIP (sai software) I can lower via curves, but that messes the colors)


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[Ptzulu]

Clean the encoder strips first.
just looks like it happens in the same spot. this could also be the media.
is the ink completely dry? or tacky?

Ink is completely dry. If I lower the UV power, it doesn’t do as much gloss banding, but, it does ver tacky, enough for grease from fingers to stay on print. I cleaned the encoder, with a towel paper (that doesn’t leave fibers) and pure water (I think its the name.. the one without any minerals)

After , I did print, and didn’t notice any difference...

Here’s the encoder (two red stripes are the width of the encoder)

I didn’t cleaned the reader, didn’t remember to do that (it kinda in an difficult place to reach)

To replace, it just as to be an encoder with same length and width, correct? Or do they have special specifications...?


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[Pauly]

Ink is completely dry. If I lower the UV power, it doesn’t do as much gloss banding, but, it does ver tacky, enough for grease from fingers to stay on print. I cleaned the encoder, with a towel paper (that doesn’t leave fibers) and pure water (I think its the name.. the one without any minerals)

After , I did print, and didn’t notice any difference...

Here’s the encoder (two red stripes are the width of the encoder)

I didn’t cleaned the reader, didn’t remember to do that (it kinda in an difficult place to reach)

To replace, it just as to be an encoder with same length and width, correct? Or do they have special specifications...?


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you dont need to change the encoderstrip. i dont think it's chanable.
It's a process of elimination though.

The thing i can see is that it's very consistent. same spot.
How level is the table?

 

[Ptzulu]

you dont need to change the encoderstrip. i dont think it's chanable.
It's a process of elimination though.

The thing i can see is that it's very consistent. same spot.
How level is the table?

Spot on leveled. Did it when installing, corrected after 3months (because it is on vinyl floor, and it might changed) about 2°correction was needed.
Checked again on January (about 7months after first install) and leveled :/
At least, that’s what my ruler say, and, what a line (tensioned between two poles on either side) says...
Will check once more, because... I don’t trust me anymore :/


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[Pauly]

Spot on leveled. Did it when installing, corrected after 3months (because it is on vinyl floor, and it might changed) about 2°correction was needed.
Checked again on January (about 7months after first install) and leveled :/
At least, that’s what my ruler say, and, what a line (tensioned between two poles on either side) says...
Will check once more, because... I don’t trust me anymore :/


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What i was ment to say was how flat is the table?

if you print a solid black on another stock, does the banding appear to look the same?

 

[Ptzulu]

Oh sorry. I thought you mean leveled as in not crooked

Well, we mostly used for pvc foam and coroplast. And both there is the problem.
If I print in acrylic, with white under/overcoat, I can’t see any glossbanding like this, but, it’s a very very different type of material.
In PP there is the same problem, glossbanding.
In most papers, there is the same problem, some, like offset IOR paper, is much much less noticible (paper also absorbs a lot more ink).

Could it be profile? The standard profiles had ink limit at 100, I changed to 70 just as a quick test, and, marginally improved, but color very washed out, so, hard to be sure it is profile related, but, already planned to “throw” away standard profile and simply make on from scratch (SAI FlexiSign/FlexiPrint)

I’m more inclined for some kind of hardware related, as in UV lamps (they are new, but....) or ionizer, or ink (also newish, still 8months left for expiration). Already replaced disc filters, nozzles don’t clog, doesn’t seem to be ink starvation... too much heat/voltage? :/ heat is around 44°, voltage don’t remember.. 19.5 I think (-/+ 0.2v)

First thing tomorrow is going to load some pvc foam, make profile from scratch, at least to test ink limits and total ink limit, and print 100% Black and some rich black, or Red, since I know they have problems.

 

[Ptzulu]

This morning, on IOR 190gr paper (printer paper)

Pretty much perfect (the artifacts and green are from upload)
This paper can absorb a lot of ink compared to other media


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[samurax]

This morning, on IOR 190gr paper (printer paper)

Pretty much perfect (the artifacts and green are from upload)
This paper can absorb a lot of ink compared to other media


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Did you fully resolve the issue?
Was it the color profile?