Positive Ink Feed Simulation Test

[Deleted member 16349]

Positive Ink Feed Simulation to Test
Ink Water Balance and Density Variation Performance.

A test method presented to the PrintPlanet forum by Erik Nikkanen and Al Ferrari.

Introduction:

It is claimed that the fundamental problem of ink/water balance and its related density control problem in offset lithographic presses is due to the lack of control of the ink feed into these presses. A solution to these problems is a positive ink feed, which goes directly into the high speed roller train and which would not be affected by numerous variables. (TAGA 1997 Nikkanen)

It is difficult for the industry to accept this, until there are some public demonstrations of positive ink feed. Public demonstrations of positive ink feed have not happened due to the lack of acceptance. No one wants to be the first to test. A Catch 22.

What is needed is a simple test that does not require any modification to the press and a test that any printer can do and judge for themselves what is possible. We think we have such a test.

Positive Ink Feed Simulation Test

Purpose:

To provide a simple test that any printer can do, without press modification, to simulate how Positive Ink Feed can eliminate ink/water balance and density variation.

Definition:

Positive Ink Feed means a unidirectional controlled rate of feed of ink into the roller train.

Important Test Issues

Simulated Positive Ink Feed for this test will be done by printing a very small area, which will get all its ink from the ink stored on the roller train.

The Ductor will be stopped so that no ink can be transferred in or out of the roller train by the Ductor .

Under stable printing conditions, the density of this small area will slowly decrease as the ink in the system is being printed out of the system.

It is hoped that if the print area is very small and the ink storage area of the roller train is relatively high and that the oscillation rollers are able to move ink laterally, the density will drop slowly down a shallow slope. This slope of the plot of Density vs Impressions is the reference line for the test.


Plate Image

It is suggested that the small circular SID target, having a size from 1/8” diameter to a maximum diameter, which can be read by a densitometer if one is to be used. Please note that the smaller the SID circle the shallower the slope. Place this circular SID patch in the center of the plate.

It is also suggested to place two small screen patches (25% and 50%) away from the SID patch, at least 2” left and right of the circular SID patch so they don’t affect the ink feed to it. These screen patches can be used to get an idea of the print quality and relative size of the water operating window.

Initial Test Conditions

Before the test is started, the ink on the roller train should be even across its width and at a normal ink film levels in order to provide a consistent ink supply and print at a near normal density at the start of the test run.

The print run would start with the water set normally.

Test Run Starts

After the print SID has stabilized on this slope, which should be quite quick, then the important part of the test can start.

1. Increase the water setting to a high level.
Note any density variation visually or with a densitometer.
Look at the print quality of the screen patches.

2. Increase the water setting with the intention of washing the print out.
Again note the density result.
Look at the print quality of the screen patches.

3. Restore the water setting to the normal value.
Again note the density results.
Look at the print quality of the screen patches.

Test Run Ends

Expected Results from Different Viewpoints:

Traditional views on how the process works would probably expect that the density will drop and be washed out when extreme water settings are set. Print quality will also be expected to drop due to an expected small water operating window.

Positive Ink Feed views would expect that the density would tend to follow the slope and not be affected much by the increase in water settings. It is expected that no wash out of the print will be seen. The water operating window will be large.

Summary

The test is simple enough that any printer can do it. The results should be clearly different from what one normally would expect. It is hoped that this will finally give press operators a practical way of seeing what is possible with positive ink feed.

We are hoping that there will be curious and interested printers who will try this test and report back to the forum. Any suggestions to improve the test method are also welcomed from those that have tried it.

Good luck.

 

[The Heidelberg Guy]

Interesting Erik.........

 

[dabob]

Erik . . .

I don't have any opinion on the process but to accomplish the test (you do seem rather determined to see this out) I would think that if you went to a local print shop with decent equipment and talked to them about the process they could run the job the way you presented with you present to monitor and verify all the procedures and the cost of the job would certainly be less than a thousand dollars and more likely around 500-600 dollars and then you would have demonstrative data to support your theory.

I guess it just depends on how much this means to you.

 

[gordo]

This test appears simple enough that it could be done, if they're interested, at the Heidelberg demo facility in Kennesaw, or the MAN demo facility in Chicago for just the cost of paper and ink. It could even bee done at CalPoly ;-)

Maybe "The Heidelberg Guy" could pull a few strings?

best, gordon p

 

[Deleted member 16349]

Erik . . .

I would think that if you went to a local print shop with decent equipment and talked to them about the process they could run the job the way you presented with you present to monitor and verify all the procedures and the cost of the job would certainly be less than a thousand dollars and more likely around 500-600 dollars and then you would have demonstrative data to support your theory.

I guess it just depends on how much this means to you.

Dabob, thanks for the comment. The problem is that no matter what I would do, I would not be believed. This has been the situation since 1996.

The good thing about the test is that an independent third party can do it and see the result for themselves.

I guess, it just depends on how much it means to the industry to know what is true. If the industry does not care, there is nothing that I do that will change that.

 

[dabob]

Dabob, thanks for the comment. The problem is that no matter what I would do, I would not be believed. This has been the situation since 1996.

The good thing about the test is that an independent third party can do it and see the result for themselves.

I guess, it just depends on how much it means to the industry to know what is true. If the industry does not care, there is nothing that I do that will change that.

Erik,

It appears to me that since you are the one championing it you should run the 1st simulation and see what the results are . . . your attitude reminds me of a quote from Henry Ford . .. "If you think you can or you think you can't your probably right"

It appears to me you are of the mindset of the can't

It also reminds me of a couple of young upstarts in the silicon valley who when the "industry" didn't see any use for a pointing device for the computer . . . (a mouse) so "industry" (Xerox if I recall correctly) just gave it to them, them being Steve Jobs and Steve Wozniak . . . look what they did to the computer industry . . . take the chance!!!!!

 

[turbotom1052]

eric,
what is it that has you thinking that a test like this isnt happened during regular production conditions in pressrooms all around the world on a daily basis? Very similar conditions to the ones you suggest happen as a matter of course. Its my belief that a pressman whos really in tune with the process does this on an almost daily basis. I further beleive that its only by noticing and being aware of these sort of trends are the highest levels of pressmanship achievable.
That being said id like to share my findings....

you are right that under them conditions with the press running at a stable emulsion state there will be a gradual slope towards a declining density of the ink as a result of the ink feed into the roller train being interupted. A larger roller train with a higher storage capacity would "hang in there" much longer before a measurable result would be evident. I also agree that a short period of increased dampening to the plate would not show much of a change to the ink density. But it would only be a matter of time before the increased dampening would result in washed out print. I further submit that if left unchecked the ink emulsion would become so unstable that it would result in other visable indications in addition to a loss of density.
To take this to an even higher level id suggest that even when testing this with a stable emulsion condition (ink water balance) the declining slope towards less ink density would not be a linear slope. im certain that as the ink film becomes thinner the effects of the dampening solution at the originally stable settings would reach a point where there would become a significantly noticable drop in the curve.
All this doesnt mean to suggest that there is still isnt work to be done by press manufacturers to continue its efforts to make a better inker. But it should also be noted that although inker technology is lacking, a more effective way of delivering a water film can be improved upon too.

 

[TheProcessIStheproduct]

I don't get it...

I don't get it...

I don't understand, what would the real world inking system look like a huge train of roller to mill out and oscillate out ink from a central point that would meter ink in a way of keeping a constant ink film on the rollers? If this the idea, it already exists in many "keyless" forms in the industry: gravure, label, some web presses, anicolor, KBA gravuflow. Maybe I am missing something, but it sounds like to prove that density drops at a constant rate, with ductor off, you are looking for a way to replenish at a equally constant rate to counter.

 

[Deleted member 16349]

I further submit that if left unchecked the ink emulsion would become so unstable that it would result in other visable indications in addition to a loss of density.

Turbotom, thanks for your views. I am sure you strongly believe what you say but the purpose of the test is to show that things don't work in the way that you believe.

We all know how most pressmen and experts think the process works. There is no need to repeat what you believe. Do the test and let us know how it worked for you.

I have done tests with positive ink feed and one can NOT wash out the print.

 

[Deleted member 16349]

. Maybe I am missing something, but it sounds like to prove that density drops at a constant rate, with ductor off, you are looking for a way to replenish at a equally constant rate to counter.

TheProcessISthe product,

Yes you are missing the whole point. Please go back and read the test method again. But you are also stating a correct requirement.

It is not a test to show that the density will drop at a consistent rate. It is a test to show that changes in the water setting will not significantly affect the density along that declining slope. Also that the print density can not be washed out at high water settings.

Your point about replenishing ink at a equally constant rate to maintain a consistent density is very correct. For many years I have been talking about this exact same issue and there is technology to do it but people can not believe that it is workable because they think the density is inherently affected by water settings. I have been saying the density variation is primarily due to the inconsistent ink transfer at the ductor. This test is just a simple way to show that. Isolate the ductor and then test to see how changes in water affect density. Useing a small print target so that the ink does not come out of the press too fast and complicates the results.

So if the test shows that printing the small target is not affected by changes in water levels, then for practical purposes, having an ink feed that positively feeds the amount of ink required will result in a consistent print density of that target that is independent of water settings. This is the benefit of a positive ink feed.

 

[turbotom1052]

eric ,
are you trying to censor me here? By stating there is no need to for me to repeat what i believe sounds an awful lot like you are. Im sure your feelings on yourself being censored on this forum, by the moderators must have impacted you in such a way as to think youve got the same right. The truth be told you have repeated your beliefs on this very topic numerous times. So often in fact that the moderators have decided to shut you down, as evidenced by your being forbidden to discuss your positive ink feed theorys. Now unless your a moderator on this forum i suggest that you perhaps rethink your censorship of me lest we all see you for the person that you are.

 

[Deleted member 16349]

eric ,
are you trying to censor me here? by stating there is no need to for me to repeat what i believe sounds an awful lot like you are. Im sure your feelings on yourself being censored on this forum by the moderators must have impacted you in such a way as to think youve got the same right. The truth be told you have repeated your beliefs on this very topic numerous times. So often in fact that the moderators have decided to shut you down as evidenced by your being forbidden to discuss your positive ink feed theorys. Now unless your a moderator on this forum i suggest that you perhaps rethink your censorship of me lest we all see you for the person that you are.

Say what you want. I did not mean to censor you. I am just suggesting that doing the test might change your view. This post is about the test. In this post I am not arguing about positive ink feed. I am presenting a test to show its benefits.

Maybe you are worried about how it will turn out?

I am not a press operator. You are a press operator. What if I turn out to be right and you turn out to be wrong? Could that then mean that one should not believe press operators because for all their experience, they do not really understand the process?

I am trying to move this subject from one of opposing opinions to something that can be tested and make it more objective.

And I would add, that I am not prevented, yet, from discussing positive ink feed on this forum. They don't want me to talk about a particular technology. So I don't talk about that technology now or in the future on these forums.

I am trying to move the process forward against great resistance. What are you trying to do? Are you trying to save the industry from the chance of positive changes?

If you are so sure of yourself, the test should confirm what you believe.

 

[turbotom1052]

As ive stated before I, and im sure many others have performed this test numerous times over the course of the years. Lessons learned from practical experience, in the trenches, doing the job day in and day out have taught me that my position on this is correct. I was willing to give it to you Eric, that theres need for improvement in the ink delivery of the offset process but you couldnt be happy with little victories.
Ive even openly on this forum acknowledged that your positive ink feed may be a viable alternative to the present technology available. But it would appear that your frustrations with not being able to commercially market your product has caused you to feel at odds with a good deal of the printing community. Yes positive ink feed sounds like something that may have its benefits if its able to become commercially available at a reasonable cost. It may even work better than whats currently available. However i dont feel that a positive ink feed of any kind will eliminate the variables of the process.
At some point you should have a respect for some of the conventional wisdoms that are out there. I know you feel that your swimming against the current in trying to bring your ideas to market but your incessant need to disparage the very people you hope to convince is in my opinion hindering you rather than helping you.
Ive heard you before liken yourself, and your views to other people in history that had to make believers out of the non believers. But i must tell you that for every person that was able to do that successfully there must have been a thousand that were just too arrogant and misguided to see the futility of their cause.
It is with all earnestness that i ask you to be as open minded to all the nay sayers that you expect of them. Your views that may be to an extent valid are not the be all,end all when it comes to these discussions.
In closing id like to say that i will try your test in the interest of keeping my mind open to the possibility that you may be right about excess water having no bearing on ink density, however when my position is proven i dont want to hear how the test was not performed properly or that the results were skewed to defend my position.

 

[Deleted member 16349]

In closing id like to say that i will try your test in the interest of keeping my mind open to the possibility that you may be right about excess water having no bearing on ink density, however when my position is proven i dont want to hear how the test was not performed properly or that the results were skewed to defend my position.

Since people have not believed me when I have said I have tested positive ink feed and got the results that I got, I would be just as skeptical of a single test done by someone who has an interest in it failing. Also test are sometimes difficult to do correctly. There can be several reasons for problems with doing a test.

Please do the test but I would hope that others will also do the test so there can be multiple results. Repeatability of test result is very important.

As I have said before, I have done positive ink feed tests on three different presses with different prototypes. The results have always been the same. The density is consistent and can not be washed out.

I have no problem with people who are skeptical. Being skeptical is healthy as long as it is not so over done that it prevents new possibilities. That is what I don't like.

Thanks for having an open mind. I look forward to your test observations.

 

[TheProcessIStheproduct]

Is this some kind of inside joke or a real discussion?

Is this some kind of inside joke or a real discussion?

So the test is supposed to demonstrate that with ductor off, plenty of ink on rollers, and a small target that prints on the sheet with proper density, can NOT be washed out by throwing tons of water at it? I have disproved this theory a hundred times, you can wash any form out with enough water and what does that have to do with positive ink feed or ink keys? As I stated before, this is not a novel idea and it has been commercially viable for a long time in waterless environments and gravure printing and label printing, special plates like waterless plates make the water issue a moot point. Problem is you are trading water balance variable for temperature control variablea

 

[Deleted member 16349]

I have disproved this theory a hundred times, you can wash any form out with enough water and what does that have to do with positive ink feed or ink keys?

There is a difference between what you have been doing and this test. All I can say is be patient. Let's see what the test results show.

 

[inkinveins]

In the name of Science, I will perform this test in the most controlled environment possible. I have been running a press for a number of years, but I can't honestly say that I have tried to flood the train with the ductor off. I am very anxious to see the results. As far as the comments regarding waterless, I believe Eric is referring to Offset when he speaks of Positive Ink Feed. Obviously with ductor off we are going to see a gradual decrease in Density, but the question is would a dramatic and rapid decrease take place, upon the introduction of extreme dampening. It has been stated that this ocurrs every day in production, which is probably true, but not with the sole purpose of research. It took me along time to finally understand and grasp the concept of " positive ink feed ", but I believe it does have merit. For any reason, if any ink remains on the ball after it ducts ( And we all know it does ) then we have lost direct relationship between ink key opening and image area rate. I have no pre-conceived notions, nor any hidden agenda, I will remain objective, I do have an idea of what I think will happen, But I will disregard these thoughts until after completion of the test.

 

[Deleted member 16349]

For any reason, if any ink remains on the ball after it ducts ( And we all know it does ) then we have lost direct relationship between ink key opening and image area rate. I have no pre-conceived notions, nor any hidden agenda, I will remain objective, I do have an idea of what I think will happen, But I will disregard these thoughts until after completion of the test.

Inkinveins,

I am glad you will try the test.

I am concerned that there may be some confusion with the requirement of stopping the ductor. Since in some locations, the ductor means the ink fountain roller, I am hoping you understand that in this test the ductor is the roller that moves back and forth between the ink fountain roller and the roller train.

And when I say the Ductor should be stopped, I am saying that it should stay in contact with the roller train for the whole test.

I hope that's clear. Good luck.

 

[inkinveins]

Eric,
Yes, when I speak of the ductor, I talk about the roller that transfers ink from the fountain or well to the roller train, ( the one that moves back and forth, hence the term, " duct " ). And yes with this particular press the " Off " position means it no longer ducts, but remains in constant contact with the rest of the train.

 

[Alois Senefelder]

Witness for the Prosecution

Witness for the Prosecution

Hello fellow Lithographers,

I Alois Senefelder of the Parish of Solnhofen, being a witness for the prosecution in the case of --- Deus ex Machina - V - ITB present some evidence deserving of your attention.



Regards, Alois, see PDFs


" Where would we be without a little frivolity "

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