Ink build up metering rollers

[glmyking]

Ink builds up on pan and chrome rollers. No pattern-sometimes 1 tower 2 or all 4. Printing 4 color process. Sometimes it is instant and so fast it stops the pan rollers. Going on since Oct. No change in fountains soln or ink. Desesitized chrome, replaced 3 chrome, 1 pan roller replaced in last 4 weeks-no change. Happens much less on first 8 hour shift. Tried different ink, varied fountain soln mix and temperature. I can run 8 hour shift no prob. then 8 hours without a good sheet. Cleaned entire system, fresh fountain soln and still fouled rollers in very short time.

 

[Kaoticor]

For the best comments, it would be good to list what kind of press you have, since some of them have different water systems and your answer can vary depending on that.
Couple of things I would check:

1 - Mixing the right fountain solution amount? No new trainee's on press mixing the wrong amount?
2 - I would get a chrome roller cleaner in there right away. You can get a small bottle for cheap from Prisco and that will tell you a lot of whats going on. Even if you haven't changed anything, we have had them start to pick up ink all of a sudden.


-K

 

[REYES1377]

This sounds like the works of a Komori!!

 

[Cornishpastythighs]

Only one question, when you say you tried different ink was it different batches from the same supplier or ink from a totaly different supplier?

 

[Ajax]

Etch your chromes with straight fountain solution on a cotton pad. Let it dry until the chrome looks cloudy. The longer the better. Then wipe off with your water solution. That should keep them wet all day.

 

[glmyking]

The press is a Didde with attached gannicott. We use Anchor 20/20 fountain solution. Thinking we might have a bad batch I mixed new soln from a new barrell. I have tried different temps and mix ratios to no avail. The inks were Sun chemical and Central ink. The chrome rollers have been replaced on 3 of the towers, all of which have been cleaned with a standard etch and then gummed several times. Our other three- 4 color press's are having the same problem. My press having only 4 towers I believe is the worst for the lack of a pull tower. The black ink towers on all the these press's also have problems with ink stripping. We run a specialty paper but the supplier and the mill say there has been no changes to the paper.

 

[pacificiam]

fountain conductivity

fountain conductivity

Hi,

We faced same problem in our machine for some time back.
To avoid this problem we maintain our conductivity between 800-1200 micro Siemens.

It solve problem compliantly. Sometimes inks not run on at high speed due to fountain.

You decide the conductivity and then run the press

 

[glmyking]

We do seem to have a problem keeping conductivity steady, I will focus a little more on that aspect. At this point it seems to be a combination of things that have just collectively came to a head. We have a roller expert coming soon with claims of a solution to this prob. I am learning a lot more about the chemistry of offset printing.

 

[Lennyr]

Sounds like chrome rollers are desensitized. Use chrome roller cleaner or mix a 50/50 solution of water and distilled white vinegar and wash up with all rollers engaged. You don't want to do this every day; or even every week, but when you're having this type of problem it usually works.
Lenny R.

 

[RGPW17100]

I am a sheet fed guy not a web but uncoated stock keeps getting worse with fillers and brighteners. When I run long uncoated runs my conductance hits the roof. I can run at 1200 micros to 1300 with coated stock all week but can go as high as 1700 running uncoated. I am guessing with web your stock could be worse with this. If I run minimal uncoated stock I can go up to three weeks without doing a fountain dump. If I run a lot of uncoated I have to change the chiller every week

 

[glmyking]

Vinegar wash sounds like it would help now to smuggle it past the waste stream security.