Weird lines in presswork - any ideas as to cause?

[Repro_Pro]

This seems to be processor related.
Check the roller/brushes pressure (evenness) and refresh developer.
Sometimes the Dev replenishing pump is not doing its' job properly.

 

[Marc.Ram]

This seems to be processor related.
Check the roller/brushes pressure (evenness) and refresh developer.
Sometimes the Dev replenishing pump is not doing its' job properly.

Hey Repro

While its possible, it seems to me that me.awash is experiencing an exposure issue on one side of the plate based on the evenness and repeat-ability of the lines. I would not expect such consistency for a processor based problem. of course you could hide the problem by delivering more energy to the plate by increasing the scrub pressure and/or overdeveloping the plate, however if you are doing critical colour this will also affect your dot percentages.

Just my humble opinion.

Marc

 

[aqazi81]

I have same problem. In my case, wierd thin vertical lines appear on the left side of the plates as you can see in the pictures I uploaded. We have been overdeveloping the plates to get rid of those lines. When developing, those lines are not visible with naked eyes but soon we start printing, those lines appear right in ourfaces. I tried to underdevelop the plates to observe the pattern of those lines and got to see them clearly as I have uploaded the picture of the plate too. Left pic is the plate and right pic is the result after printing. Didnt have any issue earlier but recently we have been bothered with this problem. Any solution from you guys would be very greatful.

It's definitely a Focus or Zooming issue,Ask your service guy to adjust the focus and zooming.
Also let us know which CTP it is.
Measure your plate thickness as well with a micrometer and see if its the same thickness as on the plate label.

I hope this helps.

 

[Repro_Pro]

To zero-in if this is a CTP imaging issue - rotate an imaged plate before it enters the processor.
If the lines show on the same side (image-wise) namely, rotated - then it's CTP related.

 

[me.awash]

Hello guys, sorry for the late response. The machine we are using is Kodak Magnus 400. Plate processor is Glunz & Jensen Interplater 85. We are currently using chinese plates. Those lines appear on the left sides only. I don't think its a processor issue because those lines appear where they are if you process either horizontally or vertically.

 

[Marc.Ram]

me.awash you May have a problem with the fiber head not sliding smoothly on one side of the Vgroove. When last was your Magnus Serviced?

the Tech normally cleans the Vgroove and replaces the Oiler brackets as part of a PM service. There is a specific silicone oil that is used for lubricating the Vgroove. Depending on the age of the machine, the Rulon pads may also need to be cleaned.

Marc

 

[me.awash]

Marc.Ram we bought the machine in 2014 and havent cleaned the Vgroove till date. Will ask my Tech to inspect on Vgroove and Rukon pads and let you know if the problem gets solved

 

[me.awash]

Cleaned the v-groove and rulon pads. Also greased it. Worked fine for a week but gradually those lines are starting to appear again.

 

[nelly]

I had a similar issue with a screen platerite processor. Turned out it was uneven wear of the scrub roller cover over time. Stuck a new one on and reset the roller and all was good. Now, if you process the plate by rotating it and the issue shows up in the same place on the plate then it cannot be the imager or processing and must be the plate batch I would say.

 

[me.awash]

The lines appear on the same side. Does not make any difference whether I rotate or not. Must be the grease issue again because it was running fine for about 200 plates before those lines started to appear again.

 

[me.awash]

Also one thing, our machine vibrates too much. The drum where plate rolls shakes after around 50% expose task. Also, there are no screws at the bottom portions on the base of the drum. Shouldn’t there be some bolts holding firmly the base of drum? I can literally shake the drum a little bit with my finger.