Do Printers Believe in Continuous Improvement?

[tmason]

Erik,

I just re read you first comment. If the technology is out there to control density why is it not adopted by the press manufacturers? Are we being duped by the man????

Todd

[tmason]

Erik,

I searched the posts that you have started and now understand what you are talking about.

I am curious how the ITB system solves the ink water balance. On the press, ink and water migrate together to form a positive emulsion. This needs to be in balance to produce optimum results. There is always a small amount of water in the ink train and when the press shuts down, the water begins to evaporate from the ink. When the press is started again, the first few sheets are generally darker because there is less water in the ink. How does the ITB stabilize this condition?

I must tell you, this is the first time I have heard of your system. I am open minded to new technology to improve anything we do. However, after reading some of your comments I feel your are disrespecting the industry you are targeting for your product.


Todd

[meddington]

However, after reading some of your comments I feel your are disrespecting the industry you are targeting for your product.

Erik's been posting his mantra for years, and in his defense, I feel what you perceive as disrespect is really frustration from one who sees the industry in uncertainly, and moving in a direction of symptomatic fixes rather than treating the root cause of the issue. Not saying you have to agree with him, but I don't doubt that anybody who didn't care about the industry would keep it up for as long as he has.

[Erik Nikkanen]

Erik,

I just re read you first comment. If the technology is out there to control density why is it not adopted by the press manufacturers? Are we being duped by the man????

Todd

No, you are not being duped. It is a cultural problem in the industry and the press manufacturers are just as much victims as anyone else. It is a problem of not looking at the reality of the process. When one hears during one's whole printing career that the process works in such a way and there is no other voice to say that that is not true, then it is very difficult to think in different directions. The cards are stacked against you.

Also within the process, there are several problems that interact with each other and this makes analysing it difficult, especially when there is so much myth to confuse the issues. The industry is still not a science oriented industry eventhough there is a lot of technology in the industry. Science is aimed at finding out truth and the industry tends to avoid truth and clings to myths that are not directly analysable or can be tested.

[mattf]

Erik's been posting his mantra for years, and in his defense, I feel what you perceive as disrespect is really frustration from one who sees the industry in uncertainly, and moving in a direction of symptomatic fixes rather than treating the root cause of the issue. Not saying you have to agree with him, but I don't doubt that anybody who didn't care about the industry would keep it up for as long as he has.

I gotta agree as well. I myself came out of Rochester Institute of Technology with a great sense of pride to know that I was joining a industry that had such a long and consistent history. Hell, even my Great-Uncle worked for the Boston Globe as a Linotypist. But when I entered the workforce I saw an industry almost crumbling away and hurting itself over and over again. And really, the uncertainty of "whats gonna fix us" is not the same answer anymore, and that's the biggest problem. Every companies problems might be close to the same, but in the end every print company is unique and the problems they face are also unique.

Trying to find the best way to tackle these unique problems in a systematic way is at times hard. But methods such as Lean, Six Sigma, TPM, QRM, TOC and even RCM has the potential to help within our own respective companies. Whichever is the best is always up for debate, but the fact remains that in order to be able to survive you need to have a plan for the long term. I know my current company does not, we are just trying to survive. But what if we could find a way to stick to a system that creates a sustainable model? All these methods can work, its just up to the company as a whole to embrace those methods.

As we all know, change almost never goes over well when no one cares to try...

[tmason]

Erik,

In your first comment, you stated measuring, adjusting and measuring is a failure. Does your system eliminate the need to open and close the ink keys and check for density variation? Are you saying we will be able to run our jobs with your system and not need to make any adjustments like fountain speed or water roller speed?

When we look at equipment investment and process controls, we have to choose proven technologies that have the greatest impact on our operation. We only have so many resources, including time and money to venture into new areas. I would like to see other people develop and perfect a new technology before we invest. We waited two extra years to go CTP and saved about $300,000 on our system. If we would have waited one more year on our latest press purchase, we could have gotten a machine that can change plates while the press is washing up.

[Erik Nikkanen]

Erik,

I searched the posts that you have started and now understand what you are talking about.

I am curious how the ITB system solves the ink water balance. On the press, ink and water migrate together to form a positive emulsion. This needs to be in balance to produce optimum results. There is always a small amount of water in the ink train and when the press shuts down, the water begins to evaporate from the ink. When the press is started again, the first few sheets are generally darker because there is less water in the ink. How does the ITB stabilize this condition?

I must tell you, this is the first time I have heard of your system. I am open minded to new technology to improve anything we do. However, after reading some of your comments I feel your are disrespecting the industry you are targeting for your product.


Todd

OK, these are good question. The term Ink/Water balance is used for different things. For the operator, the term is used when he must adjust the ink and water due to their interrelationship. He might increase water, which in turn reduces print density, so he increases ink. He has to balance these inputs.

Sometimes the term is used for the condtions on the plate where there is enough water to keep the plate clean in the non image area but not too much and enough ink to print to the right density. Sometimes it is a term that is some how conected to the level of emulsification of the ink and water.

My interest is with the density control problem and therefore I am talking about the Ink/Water balance that the operator must deal with.

The problem is very simple and not complicated as most have been lead to believe. The density control problem has always been and will always be a mass (ink) flow problem. It is not a chemical problem. The ink water balancing problem that the operator sees is due to the interrelationship of ink and water in the press. Not in a chemical way but in a mechanical way. It has to do with the ink feed into the roller train by the ductor. When water is increased, some of this water moves up the roller train and reduces the amount of ink that gets fed into the roller train by the ductor. The operator then increases the ink key setting to restore the lost amount of ink feed due to the affect of the water had onreducing the ink feed.

It is at the ductor that the ink and water are interrelated in the feed rate of ink. The ITB breaks this interrelationship by forcing the ink from the ink fountain roller to the roller train in a way that is not affected by the amount of water. With the ITB, one can not wash out the print even if you set the water to max.

This breaks the ink water balance. That does not mean that one should run with lots of water and that it does not matter how much water one uses. When the interrelationship between ink feed and water feed is broken, then you set the ink feed for the density you want and set the water feed for the quality of print. Changing the water will not affect the ink feed and therefore the density.

A washed out print is not low in density because there is lots of water but because there is little ink being printed.

Conservation of Mass is not a theory. It is such a well established concept that it is considered a Principle.

The ink that goes out on the paper MUST equal the ink that goes into the roller train during steady state condition. This means that if you feed ink into the roller train consistently, it must come out consistently. If you run at one density level and adjust something and the density drops, you should ask the science oriented question. Where did the missing ink go? If you don't know, then you really don't understand the process.

When you start a press, the press is not in a steady state conditions but is at the start of a transient which will converge to the steady state value. If you have a positive ink feed which will feed ink independent of changes in water, temperature or press speed, and if you have an accurate presetting algorithm, your print will converge quickly to the target densities. No one has to adjust it. No closed loop required. Just calibration.

There are all kinds of other benefits with moving to positive ink feeds which are not possible with what exists now. The ITB is just one very simple and low cost way to do it. Breaking up the interrelated condition of ink and water feeds, is the most important problem to correct before the offset press can advance in a scientific way. In a consistent and predictable way. In a low cost way.

I hope that has given you some ideas.

[tmason]

Thanks for the explanation of the ITB process.

One area I disagree with is that the amount of ink applied to the rollers must equal the ink applied to the sheet. In theory it should, however when excess water is applied to the ink train it causes over emulsification of the ink. The print is light in density due to the water in the ink suspending the ink on the rollers causing it to build up instead of transfer to the plate, blanket, and substrate.
A perfect example of this is on a Heidelberg alcolor system. The bridge roller between the dampener and the first ink form is where the excess ink accumulates first. The excess water does not allow the ink to transfer to the plate properly therefore the ink builds up in the ink train. This would be easier to overcome if we still ran 10% alcohol and the water evaporated quickly. This is not the case with most alcohol subs these days.
Excess water may prevent a small amount of ink from transferring at the ductor, but when the copy is washed out because of too much water, generally the water needs to be reduced, the ink feed adjusted to the proper ink film thickness for that particular color. This can be more or less ink.

I think your system would work for more consistent ink delivery but there are still too many other variables to be concerned with the to say we could set the ink and leave it. Pigment load, Ink additives for better drying on poor substrates, paper surface. If we all had 100,000 sheet runs the ink water balance and ink feed would be a breeze to control. Our runs are averaging around 2000 sheets. Fifteen MR's per day.
It is a constant moving target. Ink trap, water pick up, press speed, substrate. A press does not get truly balanced until somewhere between 500 and 1000 sheets. A lot of our runs are done by then.

[Erik Nikkanen]

Erik,

In your first comment, you stated measuring, adjusting and measuring is a failure. Does your system eliminate the need to open and close the ink keys and check for density variation? Are you saying we will be able to run our jobs with your system and not need to make any adjustments like fountain speed or water roller speed?

Yes that is basically correct.

Once the ink feed is set properly, then there should be no need to adjust it.

On the water side things are a bit different. Water does not only go out on the paper but it also evaporates. Evaporation would be related to press temperature, environmental conditions in the pressroom and speed of the press etc. Therefore water does have to be monitored to avoid scumming or over feeding of water that can result in poor print quality.

The important thing and the thing that sells the print is that changes in water will not affect the average density. There will be fluctuations about the average but the average will be very consistent.

[Erik Nikkanen]

One area I disagree with is that the amount of ink applied to the rollers must equal the ink applied to the sheet. In theory it should, however when excess water is applied to the ink train it causes over emulsification of the ink. The print is light in density due to the water in the ink suspending the ink on the rollers causing it to build up instead of transfer to the plate, blanket, and substrate.

Excess water may prevent a small amount of ink from transferring at the ductor, but when the copy is washed out because of too much water, generally the water needs to be reduced, the ink feed adjusted to the proper ink film thickness for that particular color. This can be more or less ink.


It is a constant moving target. Ink trap, water pick up, press speed, substrate. A press does not get truly balanced until somewhere between 500 and 1000 sheets. A lot of our runs are done by then.

Tmason,

You are assuming performance in a method that you have never had any experience with. I can understand that it is hard to imagine but what I have talked about is not random theory. With the ITB you will not be able to wash out the print. That has been demonstrated many times.

Some of your comments are good and almost right. When changing the water setting, there will be some change in how the press stores ink but this is a transitory situation. If there is a drop in ink transfer to the paper, the ink feed will be feeding ink at a slightly higher rate that what is being printed. This results in more ink on the roller train, which in turn overcomes the drop in ink transfer. It reestablishes the original ink transfer rate. The final result is the same density that you had before. It is self correcting.

These fluctuations are happening all the time but if they are small, for practical purposes they are no problem because the density will always fluctuate about the average which is directly related to the ink feed.

As I said, the plate can be soaking wet and shinny but that will not affect density. Although if you are printing on plastic, it will cause print quality problems. But that kind of variation in water feed is way outside your normal running conditions. It is just a clear way to demonstrate the breaking of the interrelationship of ink and water feeds on presses.

Please think about the ductor on your press. If you backtrap ink into your roller train, some of that ink will end up in your fountain. Too much water and then highly emulsified ink will end up in your fountain. These type of conditions show that the ductor does not transfer ink in only one direction and there is a great difficulty to determine just how much ink is transferred.

Now if you have a positive ink feed and an accurate ink key presetting algorithm, you will get to balance in maybe 50 impressions. That is a practical target.