Alcolor unstable water-ink balance

Your welcome!

Its what I do for a living, but not all manuals are correct or they get translated incorrectly.

I'm glad it worked out for you!

Cheers!

 

"Are you using a two step fountain solution? If so you may want to increase the etch some. We run a solution that tells us to start at 3oz etch and 3oz alcohol sub per gallon. We found that we were scumming around edges so we adjusted the mix. We now run 4oz etch and 2.5oz alco sub per gallon and it is running fine. If your using a one step solution I suggest changing it."
Mr.Rite, I'm curious, what brand fountain solution and sub do you use?

 

Im having a washing out problem on the ends of the image

 

hi, new to the forum...hoping you could give me more info on setting the dampening portion of the unit....trying to get a better understanding in how to set the bridge roller.. Thanks

 

quick question..at the end of the day running for about 8 hrs...evrything ran ok...my metering rollers are just covered with ink...? can you give me suggestions?

 

metering rollers or pan rollers , please confirm ?

 

pan rollers

 

Give them a good de-grease with a cleaner like Varn MRC

 

Alcolor problem

Hi,

I've been here before for problems with alcolor(on GTOZ). I read the posts in this tread and i'm experiencing one of the problems described.

I tried to print alcohol free and after a couple of adjustments the result was very nice but one thing: too much water on the edges of both plate and rollers.

I can start the run with perfect ink - water balance and, from the very beginning, water stars to increase at edges and increase more to the center with every cycle ruining every image on it's path until i have to stop and start againg when the plate dries.

With 5% IPA water ruins only 1" from plate edge and stays there for the whole run. With 6% and more it starts to disappear until no problem at all.

Inking rollers were replaced. Same problem. Replaced water pan and form(bottcher) Same problem. Cleansed rilsan rollers. Same.


I loved printing without alcohol but that problem won't let me.

I can't imagine it being a mechanical problem but does not seem to be chemical or setting related.

Any ideas? Has sombody gone thru the same problem? The fix?

All experiences wellcome

Thanks
Moe

 

Moe - Check the stability of the white inking form, the z-roller adds a bit more pressure on it than the other forms receive, and often times the pins that support the roller bearings get flat spots worn into them and the excessive bouncing lends to a poor ink/water balance. Good Luck Steve

 

I'm sorry for your problems. If you are printing with the standard type water rollers, you can't work without IPA. The best you can do is reduce it by adding to the water an agent that allows you to do so. Still you have to use at least 10% of IPA in order to print perfectly. If you insist not using IPA, you have to change all the rubber water rollers to different shore, thats a measurement of hardness of rubber. Moreover it is essential you have to change the water at least every 15 days, and run the system with only fresh water (no additives) to clean it somehow. It is a good idea 2-4 times a year to use chemicals to clean to system better. Of course every 6 months you have to check and adjust all your rollers, ink and water. Hope this helps

 

Thank you mqgpress and socrates,

I looked at the rollers "pins" and they looked allrigth.(In our GTO the roller that recieves the z roller pressure is yellow...) but i have to say that it has a lot of horizontal play(2-3mm) I'll stop that and pay attention to result.

And socrates, you had that same problem rigth? (too much water on edges) Did you fix it? Did you succsesfully changes roller shore hardness(to what hardness)? or did you let go of alcohol free printing and used alcohol to fix it?(if so, how much)

I read about roller hardness and how it has to be lower to print alcohol free. I replaced rollers with botcher believing that new original rollers would eliminate the posibilitty of roller problem. I felt like that until your comment. Now i'm eager to hear more about your experience. I know many printers today print without alcohol... How can one do that? Changing all rollers? with what if bottcher won't work?

What problems would appear in a problem-less press using alcohol if you just cut alcohol and start using substitutes?

Thanks
Moe

 

Alcolor system has to use IPA to work properly. I use an additive called AlcoDown to reduce the need of IPA to 8-10%. I suppose in order to work alcohol free you need to specifically ask advice from your roller supplier. Horizontal play is not an issue, just pay attention to the pressure that leaves a mark of 2mm. My problem was the instability of water and the excess of water coming on plate. Anyway, since this system is originaly designed to work with those chemicals, I strongly suggest to follow manufacturer instructions, instead of trying. I guess recent models have a difference in the system that allows them to work IPA free. If your problem is only excessive water on the edges but still you have good balance, you have to adjust your system, maybe the pan metering is a little loose and you need to tighten up in order to squeeze the water off the edges.

 

Hi Socrates, sorry for not answering before

I've been experimenting with the machine. I've come to believe that my problem is not chemical. I'm using a fountain solution with alcohol substitute and it works well. The problem i have remains. The interesting thing is that adding alcohol does not eliminate the problem it just let me work because of the chemical reaction to that much alcohol.

A demonstrator came here and checked the calibration of everything. He was going crazy as well as it just doesn't make any sense. We could only guess two possibilities:

1: The water form roller is one year old(but it looks in very nice condition and diameter is even) and it's NOT bottcher, so it could be that or,

2: The air valves and cylinders from the alcolor system(he could hear air coming out of both valves and said it was not normal) went bad.

I had a pneumatic tech come here today and said valves and cylinders are just fine.

So that leaves me with the possybility of a bad water form or... Alcolor air cylinders misaligned(or mis calibrated or whatever wrong) on one of the tree adjustments that that system has.

Does sombody with experience in the repair field(like exheidmech) knows how to check if that is out of position???(maybe a service manual that covers that part?)

All opinions are wellcome... Please Help!

Moe

 

You said it for yourself. Increase the IPA and you'll get better. Reaction if you can call it that, happens when the ink is drying which starts at the very moment the paper leaves the blanket cylinder. In the system, IPA constrains water flow to controllable levels. I insist, if you wish to print IPA free, you have to change the dampening rollers to an appropriate shore grade. Then you will not able (even if you wished) to use IPA. Thats how Heidelberg makes their machines today, according to environment friendly policies.

 

hello.
I fully agree with what he says.
There is much concern about the Ph, but many people are unaware that commodities are buffered. ie the use of a buffered product, or use just the right amount or more 1 / 2 L. will always give the max value. 5.3 + -
, which is unaware that are changing the conductivity. that exists in multiple values. also depends on what type of plates you use the printer.