ink/water balance

[arfamoe]

Yes but talk to any press operator 10 years ago and getting correct ink/water balance was a finely tuned art learned over many years and shrouded in mystery as to how it was accomplished much like making samurai swords. (:

[Erik Nikkanen]

Originally Posted by arfamoe

Yes but talk to any press operator 10 years ago and getting correct ink/water balance was a finely tuned art learned over many years and shrouded in mystery as to how it was accomplished much like making samurai swords. (:

Of course there is a lot of skill required. But what would be helpful is a SITB.
A Samurai Ink Transfer Blade to correct the inherent problem. :-)

It would also cut through the piles of misinformation.

[Lukew]

Erik is there anywhere I can find info on this ITB of your's ? I'm just interested in how the concept works..
I can't work out how the ink can be set independent of the water settings..

In my thought's no matter how acurate the ink is transfered onto the rollers,, when ever the ink/fount has to form an emulsion there will always be a direct relationship between the two..
The transfer of ink from the ink duct be it accutate or not is only one part of the many parts that effects the ink/ water balance..

[Alois Senefelder]

Run sufficient dampening fluid to keep non-image areas clean, while trying to form a stable printing ink emulsion(water-in-ink)
A simple visual technique for locating near-optimum balance, using the GATF Star Target or the 70/80% Halftones on the Print Control Strip, watch that enough water is being fed to keep these TONES OPEN, too much water causes ---- "Snowflaky Solids" and "Wash Marks" print defects.

A too dry indicator is seen by checking the "Star Target" radial wedges at the centre for
"Ink Grains or Specks" pattern that begin to appear in the unprinted wedge area where the "Inked Wedges" are the closest to each other.

During the print run visually check the Plate Cyl. as they rotate, the plates should have a "Dull Sheen" look, at a press stop a "Thin Scum Line" on the plate lead bend about
1mm wide - even across is a good "Indicator" of correct Ink-Water Balance.

Regards, Alois

[arfamoe]

Yes all good stuff, I knew a web pressman in the UK who just listened to the snap of the blanket and paper to tell whether or not he had the correct ink/water balance, loud snap=too dry no snap=too wet, as i say a timed learned skill.

[Erik Nikkanen]

Originally Posted by Lukew

Erik is there anywhere I can find info on this ITB of your's ? I'm just interested in how the concept works..
I can't work out how the ink can be set independent of the water settings..

In my thought's no matter how accurate the ink is transfered onto the rollers,, when ever the ink/fount has to form an emulsion there will always be a direct relationship between the two..
The transfer of ink from the ink duct be it accutate or not is only one part of the many parts that effects the ink/ water balance..

Lukew,

The ITB technology has had a US patent # 6,857,366 for a while and now also
has a Canadian patent #2,288,354. You can look up the description at the US patent office. The description is in legal terms required for patents but you should get the idea.

I can understand why you have a problem with this. Part of the reason is in the misunderstanding of what happens now. You might assume that the ink feed now is accurate but this is not true. The ink key might feed ink accurately onto the ink fountain roller but the transfer of ink from the ink fountain roller to the high speed roller train is not at all accurate. You have never experienced accurate ink feed and therefore you have no direct experience. Without direct experience to a positive ink feed system it is difficult for printers to imaging what will happen. This is especially true when there has been decades of bad explanations of what is going on.

It is easy to think of ink emulsification as a factor but it is not. The ink is always emulsified. The process will not work if it is not emulsified. One of the problems with the existing inconsistent ink feed process is that when one increases water, that goes up to the ductor and actually starts to starve the ink feed. Increase water enough and you get wash out. The emulsification becomes lots of water but little ink. With a positive ink feed, you can not wash out the print. Print quality might suffer but only at extreme water setting conditions. The operating window is much larger than you would think.

The ITB is only one way to make the ink feed independent of the water, press temperature or press speed but it is a very low cost way to do it.

The ITB is not a product. My market is press manufacturers. I would not get one penny unless it worked. The biggest obsticle to overcome is changing the way people think about the problem. It is quite an easy problem when looked at from the right direction.

[Erik Nikkanen]

Originally Posted by arfamoe

Yes all good stuff, I knew a web pressman in the UK who just listened to the snap of the blanket and paper to tell whether or not he had the correct ink/water balance, loud snap=too dry no snap=too wet, as i say a timed learned skill.

There are at least two technical papers related to the acoustic analysis of the splitting of the ink film in the roller train related to ink water balance. So some researchers have followed that path of the skilled pressmen.

[Alois Senefelder]

A loud " Snap" equals POOR tension control of the Web - Too much Water results in A WEB Break + and a Blanket Cyl. wrap !!!!!!
Too much Ink also results in --- A WEB Break and a Blanket Cyl wrap !!!

Regards, Alois

[arfamoe]

Originally Posted by Alois Senefelder

A loud " Snap" equals POOR tension control of the Web - Too much Water results in A WEB Break + and a Blanket Cyl. wrap !!!!!!
Too much Ink also results in --- A WEB Break and a Blanket Cyl wrap !!!

Regards, Alois

Come on now you are citing the extremes of ink/water flooding and starvation which of course would cause blanket wrap up even on sheetfed presses, i guess this pressman knew his press and the sounds it made, very little technology on the press in the old days (early sixties) and running a litho press was not an exact science.Mixing our own fountain solution, ink that varied by the batch, Blanket technology nothing like it is today and offset plates, well they still give me nightmares. The bloke was from your neck of the woods and calling someones else's comments here Rubbish is not very sporting now is it old chap.
Regards Arf

[PatQcCa]

Every reply to the original post are single way to resolve ink/water balance.

Each explanation reminds me a problem that has been occured on a press or another one day or another time...

There is no ''one big solution'' it's a receipe between 3 things: goodwill, good running press and good operation...a lack of 1 ingredient or a part of the 3 ingredients may result in many problems.

I really like the way everybody try to explain the problem...great community.

Pat
(sorry for my bad english)