Random spots on saphira violet plates

[Prepress RSC]

We are having issue with spots on the plates. You can't see them until they roll up on the press..we have gone to the erxtent of having HB put a new processor in. We clean every 400meters, change the water in the centrifuge evry other day, have bleached the system. We have a raptor pro 85 processor

Is anyone esle having these issues and how did you fix them....we ar losing tones o f press time cleaning and remaking plates

Any help is appreciated

 

[klh]

What kind of "spots"?

You say you cannot see them until they roll up on the press. . . Are they always from the same cylinder on the press? Are they on different cylinders, but in the same place? Do they move around? Do you make plates for more than one press, if so does the problem occur on both?

I'm asking all of these questions because I had the same problem where I work. Depending on your answers, I may have some for you. By the way, Heidelberg also replaced by Raptor Pro85 processor and it didn't fix the problem, because that wasn't the problem to begin with!

 

[Marko]

Had similar problem with the thermal plate. Ended up being some oil in the air lines on a Suprasetter74. I know the Prosetter has a different system but, just a thought.

 

[Prepress RSC]

sorry for the late response --but...

sorry for the late response --but...

the are very small -look like pin holes, different cylnders and they move, occurs on different press 2-40's and 1-29 press. I thought we had it licked we replace the extra wash filter with a higher density filter and that helped but has not solved it--they go away for 3 days and return.

What kind of "spots"?

You say you cannot see them until they roll up on the press. . . Are they always from the same cylinder on the press? Are they on different cylinders, but in the same place? Do they move around? Do you make plates for more than one press, if so does the problem occur on both?

I'm asking all of these questions because I had the same problem where I work. Depending on your answers, I may have some for you. By the way, Heidelberg also replaced by Raptor Pro85 processor and it didn't fix the problem, because that wasn't the problem to begin with!

 

[florin f]

HI,

this is not a procesless plate, right? On the n91v this was caused by:
- filter type ( you hae to get the metallic one)
- water temperature- when washing the coating the water has to be over 19 Celsius degree. IF less then the coating is not washed away
- bad pressure of the rollers, brushes- we never imagined the G&J 85 is not corectly setup in terms of pressure from the factory.

check these . if not sucessfull come back. I spent 300 hours fixing these on customers.

florin

[email protected]

 

[rbailleu]

are they always in a similar spot on the plate or does it move around. might be dust in the prosetter.

 

[florin f]

Hi, of course they are not in the same place as this is randomly generated by the mentioned causes. Dust in the CTP? Yes, this might be also an option. But I assumed you clean it every 3 -4 days, right? Moreover some CTPțs have a blow air system right before the laser beam. Check if this is still having enought pressure ( filters might be again changed).

Florin

 

[florin f]

Sorry,

dust in the CTp is out of the question in case you get spots. It is only valid if you get missing spots! Caus the plate is negative in behaviour. So again: check the brush and the roller in the dveloping machine. You might find they are dirty.

florin

 

[florin f]

OR brush pressure not corectly adjusted.
Florin

 

[rbailleu]

saphira violet plates are positive. a dust particle will settle to the bottom of the drum. hardly ever affects plates shorter than 18 inches. but a 23 inch plate the particles settle about the tail of a 17x 22 printed sheet. this is on a prosetter 74 of course and probably different on a 102

 

[klh]

We had the same problem at the shop I used to work at. It turned out to be a combination of the paper used on press. The majority of the stock was coming in from Mexico/Central America. It was very high in calcium. When the paper was mixed with the ink (especially Magenta, which is high in calcium) and the fact the pressmen were running way too much water. . . they would have spots. Process of elimination (no pun intended) Prisco came in with a two-step fountain solution that really helped. On top of this, regular press maintenance and a change of house stock, the problem went away.

We had Heidelberg, Prisco, Top Level Ink, and two reps from other distributors all come in at one time for a meeting on this problem. Even though there were five people from different companies, testing and giving the same opinion, the pressroom manager insisted that it was the plates/processor. I got a brand new processor, before the pressroom did anything and it did not make a difference. . . it was once the pressroom starting taking control steps that the problem started to go away.

If you contact Heidelberg they have articles in pdf format that they can send you to back all of this up.

Good luck

 

[duct maestro]

Its obviously a press problem its to do with your fount, alcohol and water balance. Best way to tell is to put plates on and just keep running its only when you pull up the press that spots will appear unless you leave your dampers dropped on when not in production mode.