We had been in contact with our suppliers, and none of them sold N-propyl so we had two options, keep using our current fount, with a dose of 3.5% IPA or give the 2in1 fount a trial,
Trialing of the 2in1 got the nod, and it has been in the press for 2 weeks now,
Our main reason for giving it a go, was the fact that if it was to work we no longer had neat IPA on the premisise, + if it lived up to all its hype it would be a god send.
Our current fount had given us the ability to get down to 2% IPA, but as the days started getting warmer, this % number started to increase, to a point were we hovered between 3.5% - 5% IPA and up to 7% on tricky jobs, Our water % feed rate was starting off at +50 - 60 and ending as high as 75-80 on some PMS coloured jobs, which was simply too high and we could see that come summer time it would only get worse.
also the water feed % rates was unpredictable, you could print the same job the following day and have totaly different settings, this of course lowers the acuracy of cip 3 as the different water % feed rates plays havoc with ink density.
So in comes the 2in1 fount. dosed so we get a reading of 8% NPA
our water dials are starting on 35% and ending no higher then 40% by the end of shift with only the last deck near the IR dryer going up to 42 % on the odd time. the last few days they have ended no higher then 38% These figures are with both cmyk or PMS inks.
As you can see with such a stable water feed % rate, it gives you the ability to fine tune cip3 even further,
whether we're going from a light coverage job to a full coverage job, our water feed rate is near the same, and we're at correct density within 30 sheets.
The plus's we have noticed
- no picture framing (ink buildup on the impression cylinders) we used to have this problem with all the other founts we have used
- minimal water needed to keep a smear free print, so much so we have now been able to run in intergrated mode when needed, which has nearly completly eradicated our banding problem on solids without any emusification problems
- there is more detail in our work now, as even the finest screens are open, looking at the dot structure under a 40X magnifying glass shows us why, its simply holding its shape and is incredibly sharp.
-We are using less ink to achieve density, especially with PMS colours. (before hand with low IPA we did strugle with certain colours and had to run an incredibly high water % feed to stop scumming up in screens)
- Start ups are fast and scum free.
-registration is much better, less water means less distortion of the sheet.
- drying time has improved
-no more cording from the metering roller
Anyone that runs or has run polyester plates would know that they do strugle to hold fount esspecialy when the temp gets up towards the end shift, but this fount seems to knock that problem on the head, and allows the plate to run near identical to metal plates.
I had a run of 30000 sheets 2 colour PMS,now normaly by the end of a run lenghth like that I would have increased my water feed rate by at least 25 points, but with 2in 1 I had only rasied it by 5points.
John, so fair your concerns of emusification by way of the n-propyl being too good a solvent has not arose.
I feel one of the main reasons it won't is because you have the ability to run such a fine amount of water, that there is very little water feed back into the ink rollers
We printed one PMS colour which normaly gives us emulsification problems as a test, and we were amazed at how sharp the print was. with no emuslification.
I will say that, while we are not as low voc emision wise as where we were at, our print quality has greatly improved,
Its not often that you can put a new fount in and straight away, throw your hardest jobs on the press for a trial, and have it just simply work, effortlesly bonus!
I can now honestly say, I like printing with poly plates, and up until now, you would never ever hear me saying that..
