CET Flatbed gloss banding issues

[Django]

When I started this thread 3 years ago, we had a CET that ran Ricoh gen-5 heads. Now we have the newer one that uses the Kyocera print heads. It has the same gloss banding issue though. Any more info on mitigating this issue would be helpful. our only solution is to print unidirectional (slow). Artbot, did you ever think of the term for interweaving the dots?

A few questions:

1. What are the print settings? Resolution, screen, speed, pass count?
2. You are using LEDs, correct? Have you checked to make sure the LEDs are staying on or that there are not any modules that are out? Maybe the lens needs to be cleaned?
3. Is this only on solid colors?

 

[Tom Dalton]

A few questions:
1. What are the print settings? Resolution, screen, speed, pass count?
2. You are using LEDs, correct? Have you checked to make sure the LEDs are staying on or that there are not any modules that are out? Maybe the lens needs to be cleaned?
3. Is this only on solid colors?

We are using LEDs for the UV cure.

The lenses did need to be cleaned. It had two lines of black dried ink (like a fiber was raised up and wiped across the heads and then across the lights therefore painting a thin line across the heads). We scraped it with a razor and wiped it many times. That fixed the unidirectional issue.

Bidirectional printing is still not an option. We are printing a big job with filled backgrounds (yes, it has a slight fade). The overlap or screen is .33. I'll have to check the other settings.

-Tom

 

[Django]

We are using LEDs for the UV cure.

The lenses did need to be cleaned. It had two lines of black dried ink (like a fiber was raised up and wiped across the heads and then across the lights therefore painting a thin line across the heads). We scraped it with a razor and wiped it many times. That fixed the unidirectional issue.

Bidirectional printing is still not an option. We are printing a big job with filled backgrounds (yes, it has a slight fade). The overlap or screen is .33. I'll have to check the other settings.

-Tom

There shouldn't be any reasons why you are unable to do 9 pass Bidirectional printing. Even if you had to do solid or gradient prints. If its not too much to ask, what ink series are you on? It could be the ink itself, if it is not curing properly or banding.
Another thing to try would be to turn the static bars off, if you have them on this printer. I've seen static bars cause print quality issues that are drop out and banding related.

 

[D3D]

Tom, if I can ask a couple of questions. What prompted you to move from the CET Ricoh machine to the CET Kyocera machine? Apart from the gloss banding, are you happy with the printer? With either printer do you know if the gloss banding would be apparent if you printed on clear acrylic and viewed it through the other side? Or if you used a clear varnish over top? Thanks. . .

 

[chinaski]

Have you tried different levels of UV lamp?
Sometimes we can reduce this by turning off the trailing lamp on our Arizona.

This solved my problem and actually made my shadows a bit richer, maybe due to dot gain?

I'd previously tried this but with opposite lamps (lead lamp on and trail lamp off), with no success. Glad I retested this.