Hi i'm Hessel Roskam and new to this forum. I work at a newspaper printing company in the Netherlands and we have a major problem concerning blinding of the plates.
We have 2 presses, a Goss Universal 70 of 8 years old and a Goss FPS of 9 months old and the problem apears on both presses. We use AGFA Lap-V silver plates with 2 AGFA Polaris XTV imagers and AGFA LP82 developing machines. Our Ink supplier is Flint and we add solco chemicals to our water and our blancets are Reeves.
Normally on a superclean and fresh developing machine we can run max. 100.000 copies, wich should be around 200.000 acording to AGFA. When my machine has produced around 60m2 i can only run 50.000-60.000. Sometimes we already have blinding after 10.000 copies. There was one time already after 3000 copies several plates blinded.
We changed all the blancets, filling under the blancets, ink rollers, moist rollers.... etc etc. But the strange thing is we have it on a 8 year old press and a 9 month old press. We tried Sun ink but did not work. We tried draining all chemicals from the developing machine each morning but also did not work. Our water has been to a lab and there was no bacteria or some other problem in the water.
The major problem is that the moment we told AGFA we had a problem they went into defense mode instantly, they told us it is a mechanical wear of the press. But on a 9 month old press???
They also tell us we are the only company that has problems with the AGFA Lap-V silver plates but i know cases of the same problem in Belgium, Spain and also the Netherlands. And i'm sure there are more companies. Please if you know a company with the same problem or you had (have) the same problem please let me know.
Thanks
Kind regards
Hessel Roskam
Hessel,
My advise will be to stay away from press room for now.
Possible ‘prime causes’ of blinding with Lithostar plus plates are:
1- Contamination of Rinse - and / or Finisher section (in Lithostar processors)
2- Maintenance °, Processor check °°, Plate jams, bearings and Rollers on output of Rinse and Finisher section.
3- Excessive foaming in the wash-off section. This foam transfers to Finisher section/ colour change.
4- LP82 : the sucking of air through some leak(s) in the hoses / connections.
5-Complete maintenance refer to the 10 Golden Rules.
6- squeegee pressure, washing-off property.
The use of Silverlith finisher concentrate (1 + 3) in the processor
instead of the L5300b resolves the issue completely, if the above can't be located or resolved.(Quick solution)
Therefore, I advise you to apply Fresh finisher manually on the plate after the plate is out of the processor and before installing the plate on the print machine. If the problem persist use Silverlith finisher concentrate as a substitute for the L5300b in an LP processor. Your Agfa representative can help you with this.
In the case of using Silverlith finisher concentrate it is best to set the finishing temperature in both the rinse section and the finisher section at 35°C instead of the standard 48°C.
Hope this will help!
