Water in Ink Fountain

[BeauchampT]

At my plant we have been dealing with a problem for months now that I am banging my head against a wall with.

We get a RIDICULOUS amount of water back tracking into our cyan ink fountain. We use ductorless ink train (MAN Lithoman design), and have had no problems with any other ink.

I have played with our chemistry, checked, double checked and triple checked all the unit settings, and we have had a serious chat with our ink supplier. Simple fact is, until we get something back from our supplier, we have to deal with this problem.

Any suggestions as to what I could look at further?

 

[cymk]

So you think it is the water pick up level of the ink? The unit is not slinging water somewhere? Chiller is set properly? Is the ink tack rated? If not switch units, see if it follows the ink or the unit.
Try ZipSet Ink. Very high pigment level and low water pick up level.

 

[Cornishpastythighs]

I would get another supplier to get me a cyan ink to try, maybe even a couple of different suppliers. The results of that test would tell you and your supplier what to do next. I would already assume you have tried a different colour ink in the print unit to eliminate the print unit itself.

 

[Bloodsaler]

Have you checked the surface of cyan unit rollers?The hardness of roller can also affect the ink water balance~

 

[Alois Senefelder]

Questions

Questions

BeauchampT

1) ARE YOU SURE that EXCESSIVE water is not being applied during the PRINT RUN

2) Is water appearing in both TOP/BOTTOM ink ducts

3) Dampening System - separate or intergrated (MAN Hydromix)

4) Is your supplier, New or long standing

5) Have you checked the Roller Train Temperature


Regards, Alois

 

[BeauchampT]

In answer to all of the above:

This is a long standing ink supplier, and we have tested a different cyan ink in that unit (which worked fine - our supplier took a sample to work with). As far as we can get out of our supplier, though, they haven't changed anything in their formulation or supplies, and we used to have no problems with this ink, so what else changed??

Our dampening system is intergrated, and I am certain we are not over-damping (this was the first thought of everyone in our plant, so, we've exhausted it).

The problem is uniform in both upper and lower units.

Our ink train temperatures are around 29-31 C (distributor roller surface) - exact same in our other print units.

I'll check the durometer for conformity to MAN and our roller supplier's recommended. Thanks, hadn't thought of that yet

 

[Cornishpastythighs]

For the problem to be in both upper and lower print units I would doubt very much that both sets of rollers have gone bad at the same time but stranger things have happened. maybe the raw materials that your supplier is getting have changed even though as far as they are concerned nothing has changed in their process. If the issue is causing you added downtime,waste or makeready I would get some ink in from another supplier that works and have your regular supplier work on the issue. As long as its all out in the open it shouldn't be an issue for your supplier.
Just my 0.02p worth

 

[Deleted member 16349]

In answer to all of the above:


The problem is uniform in both upper and lower units.

Our ink train temperatures are around 29-31 C (distributor roller surface) - exact same in our other print units.

BeauchampT, could this problem be related to the recent high amounts of rain in the Toronto area? Maybe higher levels of humidity in your plant. Also do you have a different cooling circuit to cool your ink fountain roller that might just be encouraging condensation or less evaporation in a humid environment. Maybe the cyan is just a bit more sensitive to this than the other inks. Just a thought.

 

[BeauchampT]

We have tried another ink and given a sample to our supplier. They are looking at making some modifications.

Good point about humidity - unfortunately, had the same problem in January, and March (and our plant in the winter is dry as a desert).

I guess what I'm really asking for is any temporary measures anyone can suggest to help us achieve less waste and better control while we wait for our supplier to improve.

 

[Dan Roll]

Have you tried adding varnish (clear gloss) to the cyan ink? For the fountain solution to make it all the way back to the ink fountain the capacity of the ink to store water may be low. This is typical of inks that have a high pigment content, leaving less room in the formulation for vehicle that is the only component of the ink that can hold the water. When you add varnish, I usually suggest 10% or so to start, if the ink is too strong you will see your color density go up, rather than down, as the transfer will improve faster than you are diluting the color. This may not be your problem, but it is easy and free to test......

 

[tamale]

This may sound overly simple but, been there done that...

Before changing anything in your ink system try speeding up your ink roller and closing your keys accordingly.

Many pressmen run the fountain roller too slow thinking that a wider ink key opening is better. Not always true.

How much? start with about 20% faster, you will see a difference.

It really works.

Tamale

 

[BeauchampT]

Thanks for the idea Tamale but, um, yeah tried that first.

Thanks for the varnish suggestion.

 

[blazini]

On presses that run a fountain metering roller (micrometric or film roller as MAN Roland calls it) the metering roller needs to be set correctly or you will see these problems. If making sure that's set right doesn't help there's 2 other things you can do.

If you run alot of webs that are narrower than the press, you can have prep put mourning bands on the plates. It's just a 50% screen that runs along the ends of the plate where theres no web. The partially inked plate helps keep water out of the roller train. I run a Rotoman with a duo-trol and have never seen a drop of water in the fountain.

On Harris's with brush dampening it's almost a necessity to run air curtains. It can be anything like a copper pipe with small holes drilled along the length, one end is has a hose hooked up to a blower and the other just gets capped off. You mount it so the holes blow air at the first vibrator after the ink fountain it should have a ball valve on the line so you can var the amount of air blown. The idea is that it evaporates all the water out of the ink train and helps tremendously with presses that are hard to manage the ink/water balance. This WILL stop the water from entering the fountain. As long as you have competent maintnence people it's not hard to set up at all.