Uv inks

[Ldwaves]

I'm having a problem printing uv inks on a kba 105 perfector, I'm seeing vertical lines in my printing, I'm pulling up dry,new blankets,good roller settings.
I,m new to uv printing....learning curve??? any help would be greatly appreciated

 

[rchamness]

one of my customers had a similar problem on a new kba although not a perfector they to were new to uv our inks seem to solve their problem. One thing you have to get used to is the ink ans water balance is going to be different than conventional. UV inks tend to run with higher water settings also the transfer is not as good as conv. you will feel like you are running very high in both areas

 

[Deleted member 16349]

I'm having a problem printing uv inks on a kba 105 perfector, I'm seeing vertical lines in my printing, I'm pulling up dry,new blankets,good roller settings.
I,m new to uv printing....learning curve??? any help would be greatly appreciated

Can you describe the lines in more detail?

Are these lines very small and close together?

 

[Ldwaves]

Can you describe the lines in more detail?

Are these lines very small and close together?

Yes, they are, and the lines usually are in diffrent areas of the sheet.

 

[Deleted member 16349]

Yes, they are, and the lines usually are in diffrent areas of the sheet.

What this might be is what I call "ribbing". The lines are about a milimeter or less apart and run in the machine direction. I have seen this on a press that ran with EB inks, which are similar to UV inks and which did not have any ocsillating rollers in the upper part of the roller train. IMO the cause of ribbing is due to the splitting of a thicker ink film. As the roller turns, there is a negative pressure in the ink film just at the exit of the nip before the ink split. If the ink film is thick enough, the ink can flow laterally due to the negative pressure and form ridges in the ink which can be reinforced on repeated rotations of the rollers. A thinner ink film would not be able to flow laterally and would just split in a more irregular patern.

Because the ink film tends to be thicker, higher up in the roller train, the ribbing tends to start there. It is eliminated or greatly reduced by oscillation of the vibrator rollers. With oscillator rollers, there are points at the end of the ocsillation where the roller will be stopped before it reverses. It is suggested that if one has more than one oscillator roller in this part of the roller train that they are timed 90 degrees apart so that the lateral movement of all of these rollers are not stopped at the same time. If they are timed 180 degrees apart, they would stop at the same time.

If your problem comes and goes, maybe look at how the oscillation is working on your press. It probably can also happen if the oscillation near the plate is not timed properly out of phase or is too slow.

I hope this helps.

 

[Green Printer]

Would your ink blade be able to controll this?

 

[Deleted member 16349]

Would your ink blade be able to controll this?

No. If one wanted to develop a better press, it is important to know a lot of phenomena.

The ITB is for one specific problem and roller train design needs to address other issues like ribbing, mechanical ghosting, starvation ghosting, response time, water application, etc.

 

[Ldwaves]

Hi Eric
I just wanted to thank you and everyone else for the help and support.
I'm a conventional ink printer going uv...It's like learning to print all over again.
Thanks again
Ldwaves

 

[Green Printer]

This should help.