Who teaches the teachers?

[Deleted member 16349]

I think it would be a great idea if Cal Poly tested Erik's ITB. It would make for a great student project or a way for a teacher to educate students on problem solving techniques related to print technology.

How about it Harvey?

J

J,

As early as 2002, in my emails to HL I stated that my concept might not become a product but at least it was a way to demonstrate the science. It was in my mind also that this would be a great thing for students to work on since it breaks some barriers.

 

[Harvey Levenson]

Just based on feedback not on anything published. I guess that anything is "marketable." So let's us the word "practicality" instead.

In reality, I wish Erik lot's of luck and hope that he can prove his hypothesis. I recommend that he offer a commercial printing site the opportunity to test it in a production setting. There is a lot of unused capacity these days and there may be a company or two interested in exploring the efficiencies claimed by the invention.

If Erik is questioning our experience and knowledge base, my invitation remains for him to visit Cal Poly and spend a day with us. I'd be happy to arrange a forum for discussion and exchange of ideas as his sense of who we are and what we do is presently based on assumptions. He knows how to reach me by phone.

Best wishes and signing off,

Harvey

 

[Lukas Engqvist]

@Harvey (please don't take offence that i skip titles)
I do understand that there are issue/cases, that affect a particular problem. What that debate is is not really relevant to the discussion even if I do understand that you may feel the need to defend Cal Poly.

Please though, from an outsider who is not into that issue would you shedd some light into how institutions think? You make a statement splitting the difference between education and training. Could you please expand on that difference?
Also I am interested in the roles of institutions is to educate. (not looking to find fault i just what to grasp how you think). What is the goal of education? Is there a gap in the building of the future workforce between education and a job? Is that where training takes place? What would you call such a training centre?
I am also curious on if you have read any insight on the other posts in this thread? I believe I am not alone in having to clear up misconceptions that have been aquired. (I do not say taught, because I know that students do not always hear what is said, but none the less know that it was aquired at uni/college/polly and so belive it to be fact)
I think it would be healty for this forum at large to have a graphic institutions in the active community. (oh and welcome, I haven't seen you here )

 

[Deleted member 16349]

Just based on feedback not on anything published. I guess that anything is "marketable." So let's us the word "practicality" instead.

In reality, I wish Erik lot's of luck and hope that he can prove his hypothesis. I recommend that he offer a commercial printing site the opportunity to test it in a production setting. There is a lot of unused capacity these days and there may be a company or two interested in exploring the efficiencies claimed by the invention.

If Erik is questioning our experience and knowledge base, my invitation remains for him to visit Cal Poly and spend a day with us. I'd be happy to arrange a forum for discussion and exchange of ideas as his sense of who we are and what we do is presently based on assumptions. He knows how to reach me by phone.

Best wishes and signing off,

Harvey

This thread is not about a particular technology. It is about the interest to understand the science behind problems.

You still have not stated what Cal Poly thinks is the fundamental cause of ink water balance.

As I have stated, I don't think Cal Poly has a credible idea and I think it can also be assumed that they don't care about the fundamental causes.

I have provided a description of the fundamental cause and a way to test it. What more can I do?

History will determine who is right on this issue. And when that happens, what will the graphic arts institutions tell the printing community. Yes, we were wrong on that one, but come look at how nice our labs are?

Science is not done in labs, it is done between the ears.

I would like to add that this thread is not specifically about Cal Poly. It is about all graphic arts institutions that are technology oriented and not science oriented. This orientation on mostly technology does not help teach the teachers for study of future problems.

 

[Harvey Levenson]

A few brief responses.

Erik...and I'm still awaiting for a response to my invitation. I'll even make it more enticing. How about a two-way, interactive Skype colloquium with you as the main presenter? We'd do it in the fall when we have a full compliment of our faculty and students back from summer break.

"Science is not done in labs, it is done between the ears."? Hmm, very interesting. So much for the Scientific Method in doing laboratory research!

I appreciate your notation that the thread is not specifically about Cal Poly but about graphic arts institutions in general that are "technology oriented." At least this is a clean sweep.

Lucas,

Thank you for your very thoughtful note. I'd like to send an attachment that would provide a detailed answer to your questions. However, new to this forum I can't seem to find the "attachment" key. Can you direct me to it? Or provide me with your e-mail address and I'll gladly send it to you.

I hasten to note, however, that when I refer to "education" as opposed to "training," I am referring to what any good university does in the classroom or lab in a broad sense. It includes teaching processes and concepts, and in a technical discipline how to apply theory and think critically. Training refers to teaching operations and related tasks that are typically done repetitively. Trade schools and community colleges typically do training such as, for example, training press operators or training how to use particular computer applications. We do training at Cal Poly through the Graphic Communication Institute via our seminars and workshops (www.gric.calpoly.edu). The institute is my department's arm that provides contract services for industry: research, testing, product evaluations, consulting, in-plant training, seminars, workshops, conferences, and even publishing. This is distinguished from our academic degree program (Graphic Communication | Cal Poly, San Luis Obispo) where we focus more on educating students to understand concepts and applications on real equipment such as offset sheetfed and web presses, digital presses, CTP systems, and in advanced computer labs using the latest hardware and application software. Cal Poly's philosophy is "hands-on" and "learn by doing." We have over 33,000 square feet of graphic communication labs that are heavily subsidized by industry for such purposes.

There is so much more to this. However, I hope that I've provided you with a bit of a sense of our approaches. Again, I'd like to send you the attachment as it is lengthy.

Best wishes and, again, thank you for your thoughtful note.

Harvey

 

[Al Ferrari]

See attached, You will get that option by pressing "Go Advanced".

 

[Deleted member 16349]

I would like to say that I am not responsible for the education of young students. Others are.

I am quite happy to let history determine what was true on the specific topic of ink water balance and its related density control problem.

I will continue to push the science that I feel properly describes this issue in offset presses and will also push for commercialization of the related technical concepts. In the event I am successful with this effort, I have no intention of discussing these issues with graphic arts institutions. Others can do that.

In the end, what is relevant is not what some people think now but what can be done to make practical, effective and low cost solutions in the near future.

 

[Alois Senefelder]

Ink/Water Balance

Ink/Water Balance

Erik, so what are the "Fundamentals of Ink-Water Balance" in Offset- Litho Presses ?



Regards, Alois

 

[Deleted member 16349]

Erik, so what are the "Fundamentals of Ink-Water Balance" in Offset- Litho Presses ?



Regards, Alois

Alois, I am surprised you ask since I have been commenting on this often on this forum. But I will state it again.

Even in the modern offset press, the print density varies when disturbances happen such as changes in water setting, changes in press speed and changes in roller train temperature. I have stated that this is caused by these disturbances affecting the ink transfer rate from the ink fountain roller to the roller train. Modern offset presses do not have adjustments that are directly related to the amount of ink that goes into the roller train. On modern offset presses the ink feed rate into the roller train can change even though no ink control adjustments were changed.

A positive ink feed, by what ever means, that goes directly into the high speed roller train, which will not be disturbed by any changes in the variables above, will result in very consistent print density. One can not wash the print out.

There will be no balancing of ink and water. One sets the ink feed rate for the image requirements and one sets the water for the plate conditions. Adjusting the water will not affect the ink feed rate which in turn will provide consistent print density.

Theoretically this is based on the principle (not theory) of Conservation of Mass. The amount of ink going out of the press must be equal to the amount of ink going into the press when the press is at steady state conditions. The balance of the mass of ink in and out of the system is independent of any other variable.

This is what I have described in my 1997 TAGA paper. It is something anyone who is interested in the science of the process can test. It does not require a specific technology to demonstrate but it does require that the ink is fed into the high speed roller train in a consistent rate (depending on the image needs.). One can use a constant displacement pump.

I am not going to debate this. Besides it making logical sense, it has been tested successfully on three presses with my concept.

 

[Harvey Levenson]

Hello again Lukas,

Sorry for the delay in sending this. I had a few things to catch-up on. In any event the attached has been widely published and also appears on all accreditation reports to graphic arts university programs receiving national accreditation by the Accrediting Council for Collegiate Graphic Communications. It is Cal Poly's philosophy and approach for delivering meaningful education to students and training to industry professionals in the graphic communication profession.

It will address the question you asked about how at least our institution, Cal Poly, thinks.

Best wishes and I appreciate becoming acquainted with you. You seem very astute.

Harvey

 

[GazKL440]

This has been a very interesting read, especially coming from a mere printing machinist in Australia. I will award points to either side, but feel that i am well under qualified to name a victor!!

All of you gentlemen have a very firm grasp on the theory of printing, my only question is do any of you have any practical knowledge as such? Over the years i have had some very interesting, and often heated discussion with (generally) pre-press operaters, or production managers, over what can and cant be done on a printing press. This generally relates to jobs that are set up in such a way that they will be impossible to run, and some of these people tend to refuse to think outside the box, and believe that time saved is money earned, and this can conflict with my "do it once, do it properly" tendancies.

These "discussions" tend to result from a clash between practical knowledge gained over a lifetime of working on and around printing presses, and knowledge gained from reading on the net or perhaps "Australian Printer" magazine or some other such publication.

I for one would be very interested to see a proven demonstration of Erik's ITB. As it stands, keeping density stable on a job be it short run, long run, heavily inked or a very light take off run is NOT a problem. Experience teaches you how a press will respond to any given variable, be it roller or ambient temp, be it press speeds or press/roller condition, or any other variable you could mention.

One question for you Erik: whilst i am sure the ITB combined with closed loop tech etc will be able to keep density consistent throughout a press run, i am sure there are other variables that the ITB cannot control that only a pressman can sort out. For example, marking or perhaps spray powder build up on a back up that wont effect solid density but definately will have an effect on screens and half tones. (granted, on a single pass perfector this wont be an issue).

These things are simply part of my day as a printer, another issue to be noted and dealt with as per normal. As is density control. In general, a printer responds to density changes by adjusting the sweep or profile. But in the real world, a good printer knows it is going to change, however minutely, and pre-empts the change to keep it perfect, all day...every day.

So thank you for the above discussion gentlemen, and my thoughts are if you would like some insight into making printing better/more productive/easier etc... talk to the men who are on the presses, getting their hands dirty, who have a practical, if unorthodox understanding of the entirety of the print process. I feel that even Cal Poly could benefit from having some old school and new school printers to help "teach the teachers"

 

[stu]

Just my tuppence

I am a press trainer/demonstrator, before this I was a time served press minder.
Erik originally seems to ask, who teaches the teachers of the new printers and who is responsible for deciding what should be taught? obviously the principle of offset printing hasn't changed, and modern presses just use more and more automation and processes to control and monitor this basic principle. These processes were developed by press manufacturers to improve speed and reduce the variances and inconsistencies of operators, all driven by sales and marketing.
With the abundance of presses and the speeds in which the technology moves it is surely impossible for colleges and universities to have access to an example of every printing machine, therefore it is their responsibility to cover the basic principles thoroughly (as no employer will) from a scientific angle. After the science has been covered, they then need to teach students primarily in the most relevant technologies with regards to getting the best employment opportunities in the future. The most relevant technologies are surely the ones most widely adopted by the industry.

When I learned to drive I was told by my instructor 'I will teach you how to operate a motorcar, You will learn how to drive after you pass your test'. I use this analogy when teaching people how to operate a press

 

[inkinveins]

Alois, I am surprised you ask since I have been commenting on this often on this forum. But I will state it again.

Even in the modern offset press, the print density varies when disturbances happen such as changture. I have stated that this is caused by these disturbances affecting the ink transfer rate from the ink fountain roller to the roller train. Modern offset presses do not have adjustments that are directly related to the amount of ink that goes into the roller train. On modern offset presses the ink feed rate into the roller train can change even though no ink control adjustments were changed.

A positive ink feed, by what ever means, that goes directly into the high speed roller train, which will not be disturbed by any changes in the variables above, will result in very consistent print density. One can not wash the print out.

There will be no balancing of ink and water. One sets the ink feed rate for the image requirements and one sets the water for the plate conditions. Adjusting the water will not affect the ink feed rate which in turn will provide consistent print density.

Theoretically this is based on the principle (not theory) of Conservation of Mass. The amount of ink going out of the press must be equal to the amount of ink going into the press when the press is at steady state conditions. The balance of the mass of ink in and out of the system is independent of any other variable.

This is what I have described in my 1997 TAGA paper. It is something anyone who is interested in the science of the process can test. It does not require a specific technology to demonstrate but it does require that the ink is fed into the high speed roller train in a consistent rate (depending on the image needs.). One can use a constant displacement pump.

I am not going to debate this. Besides it making logical sense, it has been tested successfully on three presses with my concept.

I would like to start off by saying that I don't know why Cal Poly or any other form of higher education in Graphic Communications is being attacked. I'm sure they are doing an outstanding job, and I bet we could all learn a thing or two from some of their courses. I am personally from the school of "trial and error", all the book learning I have done has been on my own accord, But I am encouraged by the fact that someone is keeping the flame lit in the art of teaching "Graphic Science". Back to Eric's positive ink feed principle, I do agree with the fact that the ink going in MUST equal the amount going out, obviously if it does not, density deviation will occurr. Unfortunately a "Steady State" condition is ideal, but not always realistic. How does a positive ink feed deal with the problems of varying coverage across the ink train, If I am understanding it rite, it would have to have some sort of zone specificity. With the same current press technology, in dry offset, one can not wash the print out, ( Obviously, no water no potential ). But it doesn't matter how ink gets into the train, if a dampener is used, ink density will always be susceptible to water volume, because ink / water balance begins at the plate. Too little water and we all know what happens, too much water and the image area becomes too hydrophilic which literally causes too little ink to adhere to the plate, which in turn would lead to over emulsification, which eventually leads to the problem you spoke of, a storage issue within the ink train. So you see it is not the origin of the ink feed, but what happens after ,that is partially responsible for color variation, ( Among a million other variables ). Unless I am completely misunderstanding you, you are not talking about a fundamental change in offset lithography, you are talking about something entirely different than offset.

 

[Al Ferrari]

"But it doesn't matter how ink gets into the train, if a dampener is used, ink density will always be susceptible to water volume, because ink / water balance begins at the plate."

Well the first statement before the coma could not be more wrong. The water in the ink train moves up and down that ink train, and changes the properties of the ink the more so where it is in higher concentration. A ductor roller will take ink off the fountain ball roller less effectively, the more the ink on the ductor is emulsified with water, as Erik has often pointed out to us. So the problem is that a varying amount of water in the ink train results in a varying amount of ink transfered into the ink train. Which is why Erik has been a tireless advocate for a positive way to feed ink into the ink train. As he often says, his ITB is only one such method, and there are others.

As for "ink / water balance begins at the plate", what you probably mean is that for the ink, the plate is the source of the water, which is of course true in most, but not all systems ( There are so called integrated water systems in which water enters the ink system before either substance reaches the plate).

"too much water and the image area becomes too hydrophilic which literally causes too little ink to adhere to the plate, which in turn would lead to over emulsification, which eventually leads to the problem you spoke of, a storage issue within the ink train."

Go back and re read Erik's posts here and elsewhere. He has often reported the experimental observation that in those situations in which a positive ink transfer into the system can be achieved (situations in which water does not influence the transfer of ink into the ink train), the print density does not vary with an increase of water fed into the system.

Al Ferrari

BTW, you (and only you) can go back to your post and edit it to remove one of the duplicate instances of your quotation of Erik statement.

 

[Deleted member 16349]

I Unless I am completely misunderstanding you, you are not talking about a fundamental change in offset lithography, you are talking about something entirely different than offset.

Inkinveins,

Yes, you are completely misunderstanding the issue I have tried to explain so many times. If the ink feed is positively fed into the ink train, then water basically has no affect on the amount of ink that gets transferred to the paper. This is the critical point about having a positive ink feed. No amount of water set by the dampener will affect the amount of ink that is transferred to the paper. That is fundamentally different than what you have experienced.

It is still lithographic offset but the only difference is in the details of how the ink gets transferred into the press roller train but the performance will be fundamentally changed.

And yes, the ink does have to be fed at a rate that is required for each ink zone.

I am forbidden to discuss my technology on this forum, so I can not clarify how it does what it does.

 

[Cornishpastythighs]

My 0.02pence My understanding of a positive ink feed system is that colour is unaffected by changes in water feed. Ink picks up water during the litho process and this changes the transfer characteristic of the ink, so when the press starts up the ink is fairly stable but as the run commences the inks picks up water and it now tranfers differently requiring different ink/water feed settings to compensate, hence colour variation. A positive ink feed system overcomes this problem by maintaining a constant ink transfer on the rollers regardless of water in ink. We have all seen our ink/water settings vary during the run and from operator to operator, positive ink feed eliminates this variable. Closed loop would no longer be required but ink key presetting would become the most important electronic feature. Please let me know if I am way off base here.

 

[Deleted member 16349]

My 0.02pence My understanding of a positive ink feed system is that colour is unaffected by changes in water feed. Ink picks up water during the litho process and this changes the transfer characteristic of the ink, so when the press starts up the ink is fairly stable but as the run commences the inks picks up water and it now tranfers differently requiring different ink/water feed settings to compensate, hence colour variation. A positive ink feed system overcomes this problem by maintaining a constant ink transfer on the rollers regardless of water in ink. We have all seen our ink/water settings vary during the run and from operator to operator, positive ink feed eliminates this variable. Closed loop would no longer be required but ink key presetting would become the most important electronic feature. Please let me know if I am way off base here.

CornishPT, Yes you basically have the idea. I am quite happy to see now that you and Al are understanding the situation quite well.

To clarify a bit. In the conventional system, and disturbance that changes the ink transfer at any point in the roller train will affect the ink transfer at the ink fountain / ductor point. So a change in ink transfer at the blanket/paper interface will work back up and affect the ink storage in the roller train, which will in turn affect the transfer at the ink fountain roller/ductor point. The same can be said for any ink transfer point in the roller train. Every ink transfer point has an affect on other points and the ink feed point. This is complicated.

When on has positive ink feed, there are still changes in ink transfer at any of these points, which do affect the ink storage on the roller train BUT the transfer at the ink fountain roller/ductor point is not affected. All these ink transfer point variations then just vary only a small amount about a very consistent average. Positive ink feed maintains the average ink transfer to the paper as the final result. Fluctuations about the average are related to the roller train design itself. But basically if the fluctuations are small, for practical purposes they are not a problem.

I hope I have not complicated the picture but it is good if one can see in ones mind how ink feed rate, ink storage and ink transfer at all the points work together. The really great thing about positive ink feed is that even though the process is very complicated, it is self adjusting in the sense that the ink transfer to the paper can only fluctuate about a very consistent average ink transfer rate.

Now if we talk about ink key presetting, there is also a big opportunity for improvement. There is the zero setting issue which is mainly a press ink feed problem. Zero setting sets the datum for the ink key preset values. This is very critical for low coverage. An error of 2% in the zero setting point can cause a relatively large error in setting the ink key to say 5%. The actual output would be 7% if the zero set error was +2% or the output would be 3% if the zero set error was -2%.

The other very major problem is that the algorithms for most ink key presetting systems are not accurate. The common view is that the ink consumption per ink key is related to the image area of the plate. This common belief is NOT true. The ink consumption per ink key is NOT directly related to the image area. If one calculates the ink key setting from the image area on the plate, the error can be as high as 40%. There are several factors that have to be considered in calculating an accurate ink key preset value. It is complicated but no difficult.

So if one can obtain a positive ink feed and an accurate ink key presetting algorithm, basically one has a keyless process. Keyless in the sense that ink keys, once they are preset to the accurate values, would not have to be adjusted at start up or during the run.

This can be done as modifications to existing presses. It is not just a theoretical exercise but a theoretically directed low cost practical option for legacy presses.

It is unfortunate that teachers have no interest in this kind of thinking. But that is their problem and their student's problem.

Again, I am very glad to see that some are starting to understand these issues. Not only does it help one know what is required but it helps to protect one from marketing hype that continually pushes faulty thinking.

Hopefully these issues will be demonstrated so that you can confirm what you are starting to understand.

 

[Alois Senefelder]

From a Sceptic !

From a Sceptic !

Hello Fellow Lithographers,


Am I the only one not "Beguiled" by Mr Erik Nikkenan's ITB ?

The printing tolerance can be defined as the range between minimum water feed where tinting begins, and the maximum water feed where water marking begins. Tinting results from too little water in the non-image areas , wheras water marking is a "Disturbance in Ink Transfer" due to too much water being in and on the Ink Layers in the Image areas.

Remember - The Cylinder Gaps disturb "Positive Ink Transfer"

Some PDFs for you to ponder re Ink/ Water Balance

Regards, Alois

 

[oxburger]

One of my professors once told me: "Those who can, do. Those who can't, teach. Those who can't teach, teach teachers" Thought it was pretty humorous.

 

[Al Ferrari]

Welcome Cornishpastythighs,

"Ink picks up water during the litho process and this changes the transfer characteristic of the ink, so when the press starts up the ink is fairly stable but as the run commences the inks picks up water and it now tranfers differently requiring different ink/water feed settings to compensate, hence colour variation."

You are not way off base, and very much on target here. But let's sharpen the focus a bit more. Several transfers of ink concern us here:

Transfer of ink from the fountain roller to the ink train.
Transfer of ink from roller to roller within the ink train.
Transfer of ink from the form rollers to the plate.
Transfer of ink from the plate to the blanket.
And transfer of ink from the blanket to the substrate.

A positive ink feed system eliminates the effect of the water on the first of these transfers. The others continue to be affected. But an equilibrium is quickly reached for any water setting without the need to adjust the ink fountain settings because this transfer is unaffected by the change in water coming into the system. Now since printed ink density is the direct result of the amount of ink transfered to the substrate and this has remained constant because the amount of ink coming into the system has not changed, then ink density at the substrate remains constant even though it may contain more water than before.

Now are these sorts of ideas proper subject matter for discussion and investigation by students and professors at institutions such as Cal Poly?

Al Ferrari