Plate Catch up

[pacificiam]

Hi EveryOne,

We are facing confusing Seniro in our Print shop regarding plate catch up issue.
Please help me out to sort out this.
Our operators are facing plate catch up problem in Cyan unit only. We are facing this problem on our both machine.

So the operator star blamming on Ink. But we were running same ink from last 1 week. That time we didn't face any problem.

When we had word with our CTP guy then we found he charge fresh developer in tank.

So we start thinking that this issue is regarding plate developement.
But it why not happen with other 3 colours. Why only for Cyan?
Is it because Plate gets process in CMYK sequence?

Please send your views and opnion on this tricky situation.

 

[PhillyPrinter]

I have had this problem in the past and in our shop each unit has it's own chiller for the fountain solution.(some presses have one central unit for the whole press). Check to be sure that the fountain solution in that unit is nice and cold like all the other units. If it is not cold it will cause catch up. and also if is not cold try blowing out the fins if they are dirty. if that doesn't work you may have a bad condensing unit on the chiller. Hope this helps. good luck

 

[fireplug55]

Check you pressures on this unit. Is the plate and blanket packed to spec, make sure you are not over packed.

Check each of your plate form rollers to your vibrators, if the strip is to heavy especially on your last form it will scum or tint.

 

[D Ink Man]

Here's a good hint. The cyan in a KCMY rotation is definitely the thinnest film. This will certainly make it the touchiest for ink and water control. Think about that one.

D

 

[Ret Heidelberg Instructor]

If your operator thinks it is an ink problem then switch the units. Put the magenta in the cyan unit. If you still have a problem in the unit with the magenta, then it may not be an ink problem but a problem with the unit itself. Check roller settings and packings and see if there is a problem in the unit and not the ink.

 

[pacificiam]

If your operator thinks it is an ink problem then switch the units. Put the magenta in the cyan unit. If you still have a problem in the unit with the magenta, then it may not be an ink problem but a problem with the unit itself. Check roller settings and packings and see if there is a problem in the unit and not the ink.

We have Facing this problem on both the machine....

 

[Green Printer]

An easy test is add about 5% trans white to the cyan. This will slightly increase your ink film.

 

[pacificiam]

An easy test is add about 5% trans white to the cyan. This will slightly increase your ink film.

wHAT WILL HAPPEN WITH THIS EXERCISE??

 

[Green Printer]

wHAT WILL HAPPEN WITH THIS EXERCISE??

I would expect that your scumming would diminish or go away. If the scumming is diminished yet not eliminated add another 2.5% of trans white.

 

[D Ink Man]

10% will not hurt.

In my experience it takes a move of +/- 15% to change the ink film thickness on the vibrator roller, and subsequent rollers .1 mil. Tried and true.

D

 

[Alois Senefelder]

Plate Catch-up

Plate Catch-up

Gentlemen and pacificiam,

With good plates and good ink, Catch-up is just a indication of poor plate dampening

I suggest instead of going round in circles !!

1) On the problem unit - drop the plate inkers, roll the plate up solid, lift inkers.

2) Next drop the plate dampeners, the plate should clean up within 5/6 revolutions, if not

you have a dampening roller problem.


Regards, Alois

 

[Ret Heidelberg Instructor]

Good call Alois on testing the dampening in the unit by using the method you suggested. It will help eliminate a problem with the unit and then you might have to look at other variables such as the ink.

 

[Green Printer]

Good call Alois on testing the dampening in the unit by using the method you suggested. It will help eliminate a problem with the unit and then you might have to look at other variables such as the ink.

I know it is possible but the exact same anomaly happening on 2 presses using the same ink.

 

[Disappointed]

10% will not hurt.

In my experience it takes a move of +/- 15% to change the ink film thickness on the vibrator roller, and subsequent rollers .1 mil. Tried and true.

D

How does running a heavier ink film prevent catch-up?

My main question would be, Has this started recently, suddenly or has it always been a problem with this ink / plate combo?

Also have you recently changed inks, plates or fount solutions??

Surely you have not always had this problem?

There must have been a trigger point?

I would not start adding stuff to the ink until i knew these answers for sure.

 

[Lukew]

What Brand of ink is it ?

 

[pacificiam]

Gentlemen and pacificiam,

With good plates and good ink, Catch-up is just a indication of poor plate dampening

I suggest instead of going round in circles !!

1) On the problem unit - drop the plate inkers, roll the plate up solid, lift inkers.

2) Next drop the plate dampeners, the plate should clean up within 5/6 revolutions, if not

you have a dampening roller problem.


Regards, Alois

Its nice solution I will definatly try this out

 

[pacificiam]

How does running a heavier ink film prevent catch-up?

My main question would be, Has this started recently, suddenly or has it always been a problem with this ink / plate combo?

Also have you recently changed inks, plates or fount solutions??

Surely you have not always had this problem?

There must have been a trigger point?

I would not start adding stuff to the ink until i knew these answers for sure.

Hi,

We havent change ink, fountain or plate.

This problem have start recently.

We aren't facing this problem regularly.

 

[Cornishpastythighs]

Just a couple of points. What response have you got from the ink supplier ? Do they know you even have a problem? If you decide to become an ink chemist and make adjustments to your ink on your own who now takes responsibilty for the ink if any issues arise such as offsetting, poor drying etc. If your ink company cannot provide some technical assistance in your hour of need maybe time to look around for someone who can. Just my 2pence worth.

 

[pacificiam]

Just a couple of points. What response have you got from the ink supplier ? Do they know you even have a problem? If you decide to become an ink chemist and make adjustments to your ink on your own who now takes responsibilty for the ink if any issues arise such as offsetting, poor drying etc. If your ink company cannot provide some technical assistance in your hour of need maybe time to look around for someone who can. Just my 2pence worth.

Hi,

Before making any contact with ink supplier...
We want to be sure this problem is because of ink only.
This problme not arrive all the time.

 

[Disappointed]

Hi,

Before making any contact with ink supplier...
We want to be sure this problem is because of ink only.
This problme not arrive all the time.

Then there must be a pattern, different paper, temperatures, speeds on press etc ?????