Blinding

[Prepper]

We print our 4-color jobs in units 2-5 of our 6-color Heidelberg and then switch to units 1-4 for our 6-color covers.

Last 2 times we switched from 2-5, to 1-4 we immediately had blinding issues and couldn't print 500 sheets without the magenta going away, other colors followed if kept going.

Paper was the same, a 30%PCW, tried a different paper, same result but much slower to happen.

First time it happened they did or calcium cleanings at least twice and that solved the problem. They're telling us it isn't calcium because if we just clean the plates it comes back for a while. Press crew unsure if calcium cleanings were done in between during the 3 months we were running in 2-5.

My question is, this year they started using a dead unit compound instead of vaseline they had always used. Is it possible that 3 months is too long for that to stay in there without getting cleaned out? They say this stuff is really hard to get cleaned out, takes 2-3 cleanings. Is it possible that its just still coming out of the rollers and transferring down thru the other units causing this problem? Once they've done several cleanings things improve but by then we've wasted a lot of time and have a lot of covers with light ink.

Pressman changed inks and now there's not a problem, but they cleaned up good again before doing that and are putting in fresh inks out of new cans.

Any ideas?
Thanks

 

[Cornishpastythighs]

Roller Mate by Accu-Chem Industries

I would say 3 months is far too long to leave a compound on the press rollers. Why not leave on for a few days and then rinse the rollers and apply new compound on an ongoing basis.

 

[Alois Senefelder]

Incompetence !

Incompetence !

For allowing expensive roller trains to be ruined.


1) The roller trains should be disengaged if possible. - if not

2) Use a suitable Roller Train Lubricant , apply sufficient lubricant so the you can hear it "Whispering" as the rollers

rotate !

3) Refresh lubricant - when needed !

4) Also wash the roller trains on a regular basis .


Regards, Alois

 

[Lukew]

Who in there right mind would leave a dead unit compound on a deck for 3 months without washing it up on a regular basis.
As Alios pointed out, a unit left unused for that long should be disengaged.
Bottcher have a graph showing heat buildup in units with ink vs dead unit compound vs dry unit, and the dead unit compound deck is still considerably hotter then the ink deck.

 

[Prepper]

Ok, so how long should it be left in? What is it's purpose? Just to replace the ink, provide lubrication while you're not using that unit, and then clean it out when that run is done, like an ink? Not a pressman, just trying to help troubleshoot the problem. They may be using way too much also as they didn't know how much was supposed to be used. What they're using is called half web.

 

[D Ink Man]

An open pocket compound is certainly in order for the non running dead unit.

This compound can usually be obtained from an ink supplier of good creditability.

Usually a very good open pocked compound is a clear varnish that has heavy rheology (structure) and moderate tack, while maintaining excellent stabilty in the vehicle formulation.

A second compound can be something as simple as petrolatum or what is commony known as Vaseline.

However, I do prefer the former, as it has more longevity and performs exactly as a functioning printing ink would, lubrication provider.

In either casechanging the compound should be done daily in my professional appraisal.

D Ink Man

 

[Mike Herndon]

On a Heidelberg 6 color the units can't be disengaged per say. You can do things like change oscillation to zero, back off roller settings so they do not turn or if the unit will be down for 3 months (and you know the unit will be down no chance of using it)- take some of the key rollers like water form and ink forms out altogether.

That being said we use Bottcher Roller Lube in any unit not being used for more than 10,000 impressions, and wash up every 24 hours if we are not using that unit. The wash up pan stays in, pressman hits the wash up button while other units are washed up, walla unit cleaned and new lube put in. It's free cleaning, our rollers last a long time, well over 50-60 million impressions usually.

We calcium fix a lot, mutiple times a week based on our stocks, both coated and uncoated.

Leaving roller lube or some other kind of lube in there for 3 months? you're rollers are trashed, start over.

Mike

 

[Mike Herndon]

Ok, so how long should it be left in? What is it's purpose? Just to replace the ink, provide lubrication while you're not using that unit, and then clean it out when that run is done, like an ink? Not a pressman, just trying to help troubleshoot the problem. They may be using way too much also as they didn't know how much was supposed to be used. What they're using is called half web.

Not really sure what "half web" is. You need a roller lube, lot's of people make them, Bottcher, Anchor, or you can buy a relabed one like Spahira from Heidelberg. Their purpose is to keep the rollers cool and to help with cleaning. When you wash the lube you'll see ink and what not pulled out. Almost like like a febo clean but not as drastic. We will throw some febo on top of the lube before we wash up just to have that extra bit of cleaning. The good pressman understands- take care of your rollers they will take care of you. Management needs to understand, they must let the pressman take care of the roller train.

Why do you need roller lube? Heat and friction is what really kills rollers along with poor wash ups. Over time, sure rollers shrink, lose their "knap" and wear out. If you looked at a roller through a microscope you would see the surface is not flat or smooth but actually has texture "peaks and valleys" I guess you could say. Bottcher used to have a picture of one of their rollers showing this. These peaks and valleys move and help agitate, transfer and eventually emulsify the ink with fountain solution to create a stable ink transfer.

You lose these peaks and valleys when a roller is not maintained, the roller gets glazed due to calcium, changes shape due to heat, and the durometer of the roller will change too. The rollers ability to transfer ink is diminished, you have lost your stability. Roller lube is just ONE part of roller maintenance program, febo cleans, calcium fixes are other tools used daily to keep rollers performing as they should.

edit- if the rollers stop or sling roller lube onto the air bars and gates, you're probably using too much. How long do you leave it in? Depends on how many shifts (and how fast) you run your press. Ours run 24/7 so we do not leave lube in more than a few 12 hour shifts.

Mike

 

[D Ink Man]

On a Heidelberg 6 color the units can't be disengaged per say. You can do things like change oscillation to zero, back off roller settings so they do not turn or if the unit will be down for 3 months (and you know the unit will be down no chance of using it)- take some of the key rollers like water form and ink forms out altogether.

That being said we use Bottcher Roller Lube in any unit not being used for more than 10,000 impressions, and wash up every 24 hours if we are not using that unit. The wash up pan stays in, pressman hits the wash up button while other units are washed up, walla unit cleaned and new lube put in. It's free cleaning, our rollers last a long time, well over 50-60 million impressions usually.

We calcium fix a lot, mutiple times a week based on our stocks, both coated and uncoated.

Leaving roller lube or some other kind of lube in there for 3 months? you're rollers are trashed, start over.

Mike

Very good replies Mike. You have learned your lessons about your particular printing machines very well. You are a good man for the trade.

I hope you are still receiving 'quality servicing' from your supplier, particularly, 'ink'. You and your company deserve it and should expect nothing less. 'Boots on ground', 24-7-365. Please do not settle for less.

You are quality and must receive the same from your vendors because you pay for it! Without you, they cannot exist. No being shy sir. Demand the best! D to.yo

 

[Prepper]

Thanks Mike, good info, always helps, regular maintenance goes a long way to avoiding problems to start with, proactive vs. reactive.