Komori Lithrone S40 --Ink Fountain speed control

[Servicetech]

Graphical representation of the SET and RATIO functions

The synchronization point is the press speed that changes from SET to RATIO setting, set by console memory setting M2-1 (default setting is 38 i.e. 38% of max speed) Although if I remember correctly, this setting may have a slightly different default setting due to newer, higher speed machinery. At a press speed below the synchronization point the ink feed will be adjusted by the SET value alone, above this same point the ink feed will be INK FEED = (SET x( RATIO / 100)) and then applied to the press speed, probably with a slope intercept formula (y=mx+b)

As you can see the RATIO setting will adjust the high end of the linear slope. A RATIO setting of 100 will result in no compensation of ink feed due to press speed.

[Erik Nikkanen]

Graphical representation of the SET and RATIO functions

The synchronization point is the press speed that changes from SET to RATIO setting, set by console memory setting M2-1 (default setting is 38 i.e. 38% of max speed) Although if I remember correctly, this setting may have a slightly different default setting due to newer, higher speed machinery. At a press speed below the synchronization point the ink feed will be adjusted by the SET value alone, above this same point the ink feed will be INK FEED = (SET x( RATIO / 100)) and then applied to the press speed, probably with a slope intercept formula (y=mx+b)

As you can see the RATIO setting will adjust the high end of the linear slope. A RATIO setting of 100 will result in no compensation of ink feed due to press speed.

Hi Servicetech,

I have seen this chart. At first I was confused since I could not believe that the ink fountain speed was constant through the whole press speed if Ratio = 100. In thinking about it more, I could see that it would work if the ductor roller makes at least a full rotation when it is against the ink fountain roller.

Since the ductor acts on every three impressions, there is more time to do that and I am guessing the ink fountain roller tends to run faster than on other presses.

I also suspect that the ink film thickness on the ink fountain roller for the ink key range from 0% to 100% is probably smaller than on other presses too.

Does that make sense to you?

Thanks for any more comments.

[Erik Nikkanen]

Erik,

it will duct 1 time for every 3 plate revolutions no matter what the press speed is

Hi Inkinveins,

Does this cycle time of 1 ductor action for every 3 plate revolutions cause much variation in the print density over that period?

Also a question about the ink key range. I have been told that the full range of movement from closed to open (0% to 100%) is something like 0.016". On these presses, can the total range of ink key movement be changed to make it larger?

In operation can all of the ink keys be moved proportionally higher and lower?

I think the speed of the ink fountain issue is cleared up. I was looking for a proportional speed control and that seems to be doable with this system. Setting the transition speed at 8000 (start of printing) and the Ratio to 175 (14000 top speed on the target press) gives the desired result for what I needed.

For what we are going to be doing, there is no ductor action. The ink transfer will be continuous.

Thanks for any comments.

[Alois Senefelder]

Hello Erik,

I hope the PDF has the information you seek !



Regards, Alois

[Servicetech]

Yes Erik, You are correct about the ink ductor, I found a newer explanation of the ink feed system (see note 4 at the bottom).

I don't think there is a way to increase the total range of ink key movement, the key motors have a finite amount of mechanical movement. In fact on older machines, worn keys can cause issues. After a zero set with worn keys, you may not make it to 100% before the mechanical limit of the key motor assembly is reached.

Also I forgot to include what the ink feed motor drives get from the console for a speed reference. the console outputs a 0-10 VDC analog signal to the drive(s). Minimum speed would be 0 VDC maximum is 10 VDC. 0-10vdc is a very common analog signal when transmitting over short distances (inside a localized machine)

[Erik Nikkanen]

Hello Erik,

I hope the PDF has the information you seek !



Regards, Alois

Thanks for the PDF. I don't think it is exactly the same press but the PDF is of interest. The target press seems to have a larger ink key gap range than the one in the PDF.

[Erik Nikkanen]

Yes Erik, You are correct about the ink ductor, I found a newer explanation of the ink feed system (see note 4 at the bottom).

I don't think there is a way to increase the total range of ink key movement, the key motors have a finite amount of mechanical movement. In fact on older machines, worn keys can cause issues. After a zero set with worn keys, you may not make it to 100% before the mechanical limit of the key motor assembly is reached.

Also I forgot to include what the ink feed motor drives get from the console for a speed reference. the console outputs a 0-10 VDC analog signal to the drive(s). Minimum speed would be 0 VDC maximum is 10 VDC. 0-10vdc is a very common analog signal when transmitting over short distances (inside a localized machine)

Useful information. I was told that a 0.016" feeler gauge could be slipped into the maximum ink key gap. This should be enough of a range even if it can't be increased. So things look good for testing.

Thanks again.