Tricks for finding a low spot in ink train rollers?

Apphoard75

Active member
Anyone know of any good tricks to find a low spot in a rubber roller? We put in new rollers around maybe a year and a half ago. Not many are in bad shape and we have replaced the ones that were. So we are washing out and emulsifying at keys 13-16. So we believe we have a low spot in a rubber roller. We think we may have gotten a sheet in the rollers and never caught it. By the way we trained a new guy on the press who was my helper :) We have had this problem for around the past three months.
 
Actually me and the shop, but I put the rollers in. The unit ran fine for probably a year. Then out of no where it is washing out at keys 13-16 and emulsifying. I have shut off the air to roller washers thinking water or solvent may be dripping onto the rollers and that wasn't it. I ran a press years ago that would do that if we left the tanks aired up. So I am pretty sure it's a low spot in a roller. We have our water speed in the unit at the lowest possible setting. I have seen this problem before and it was a low spot in a roller from a sheet I found wrapped around a roller. We had the problem until we replaced them all, because we couldn't find a low spot in a roller. Actually I am sure I could have because I knew where the sheet was, but the shop just replaced them all. Trying to fix this our head pressman, replaced the water form, the pan roller and the first ink form. He did this because we run the press integrated. The press likes to tone and our water speeds are high if we run deintegrated. We run a two step fountain solution and we are dosing it heavy. Our roller chiller system isn't working that great. We can only chill the ink train to around 70 faranheight. Because of something being screwed up on the refrigerant side. I day head pressman because I am in a union shop and we have a guy that's ran all of the presses, but doesn't anymore and is above me. I run the press and he helps out if we have a problem like this and orders stuff we need and makes sure everything runs smoothly.
 
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It's a Heidelberg CX102 I believe. Some of our roller Temps get up to 78 degrees when we run fast. Any of you know your Temps on the rollers at a high speed?
 
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I suggest running a "Dry" and "Wet" solids test.
A dry solids test shows how inking system is working. Set the ink fountain keys to all the same value, uniform, even, balanced. It should print the same way.
Then run the wet solids test. You need an imaged solid plate for this, with a 1" boarder around outer edge of sheet. If rollers are not flat, not set correctly or "Glazed", the wet version should show issues.
 
It's a Heidelberg CX102 I believe. Some of our roller Temps get up to 78 degrees when we run fast. Any of you know your Temps on the rollers at a high speed?
is the problem in all units. is the problem just in 1 unit. is the problem in one area all the time or does it move
 
   
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