Banding on agfa azura TS plates

[lolchris]

Hello,

We have a Kodak Magnus 400 II MCU and we have switch to agfa azura TS plates recently (we were using heidelberg safira plates).
The technician is currently working on adjusting the settings (laser power, drum speed, etc) but still we have some light banding.
I have read that it may be cause by a high line screen (we use 150/175), please let me know if you have any suggestion that could solved our banding issue.

 

[prepressdork]

I am not familiar with Kodak machines but I will take a stab at it. Assuming that it operates the same way as my machine, the laser images in swaths that are a specific width. Perhaps the laser swaths are slightly out of alignment causing an overlap?

pd

 

[maxon]

Chris, 175 is pretty much standard no worries the plate can easily go up to 200 lines. Bear in mind it's a negative plate i.e. laser writes the image. It requires quite a lot of energy around 200 mJ/sqcm so this may be your problem. Raise the laser intensity and/or decrease drum speed. Last but not least your tech must check the beam balance and focus.

 

[lolchris]

Thank you for your fast response, please see pictures of test jobs, the tech is increasing and decreasing the laser power and drum speed but we haven't been able to reach a perfect level.

 

[tomcatinc]

If it is swath wide, try to play with beam balance (slope, curve, depth, etc).

 

[maas]

Ask the vendor to image a set of plates through one of their other clients for comparison, with 256 steps per channel available the distance covered and the amount of change from start to finish in any given gradient could the primary factor in causing banding

 

[lolchris]

Problem solved, the tech had adjust some settings (laser pwr, drum speed, sensitivity...)
thank you all for your advice