Suspicious Scumming

I feel that I post questions up here way to often, but I am new to the game and am still on a learning curve, and greatly appreciate the advice. I run a 2-color Ryobi 3302 with Crestline Dampening system. In the past week or so I have been getting a really bad scumming that manifest itself as a dark ring on the right center of my plate of my 2nd unit only. It occurs in the same spot after ever ink up. My boss suspects an oil leak w/ my press having an automatic lubrication system. We have washed the press up extensively twice, with the second time removing all train rollers and hand cleaning everything in the unit. Within about 25-50 impressions the scumming returns heavily. I am suspicious that we may have a different problem, but don't know enough to diagnose the problem. Anyone have similar problems in the past or have any probable scenarios. Thank you all in advance

 

Can you possibly post a picture?

 

If its oil you will see it on the rollers. Is the 'dark ring' the same or a different colour to the ink being used?

Have you checked all the roller settings?

 

The ring is the same color as the ink I am using, black. I have checked all of my rollers and they are correct. After extensively cleaning my press we are leaning away from the oil, but rather a glaze on one of my water rollers. I ran Putz on that unit all of yesterday while I printed on the other unit, and at the end of the day I had accumulated a build up on my top water roller, in the same vicinity the the scumming that shows up on my plate, blanket, and stock. We are suspicious that this either means that I have a dead spot on that roller, or its glazed and needs a deeper cleaning. either way we are not 100% so anyone that has an opinion let me know, trying to rule out whatever we can. I am going to run PutZ again tomorrow, then wash up and see if it helps, if not I'll have to pull that roller and see if it needs to be replaced. So yeah, not really sure

 

If your rollers are glazed you need to look at changing your washup chemical.

I'm not familiar with your machine, although if i had the trouble i'd be looking at replacing a roller or turning it around if possible

 

Yeah If I had to guess, we'll probably end up replacing the roller. It seems to me if I turn the roller, then I will just end up with the same problem on the opposite side of the machine.

 

Thats the idea....its called fault finding by elimination.

One other thing, if you know the result (damaged roller) why are you wasting your time in running a roller paste?

 

We are eliminating the possibility that the roller may be glazed, or may have absorbed something that is repelling the fountain solution. By giving it an exceptional cleaning we will be sure that the roller is not contaminated, and can move forward with removing the roller for further inspection. The water rollers are not the easiest to remove from this press, so we want to be sure before taking those measures. Do you have any recommendations on what you may think the proper diagnosis and solution could be to this problem?

 

I assumed that you'd cleaned all the rollers twice by hand, obviously this didn't include your damp otherwise glazing wouldnt be an issue.

Unless there is something touching on the roller thus reducing the damp, it still sounds like a damaged roller .

 

Hello Deadspread4
Have you tried doing a good gumming of your dampening rollers. Maybe one of them has gotten sensitive. This will cause the ink to stick to the dampening roller. Either the chrome or the metering roller(not the water form). I do not know about the press you are talking about but if these rollers are there, this could be the problem.

 

No my press does not have that type of dampening system, it is a Crestline system that uses a set of 3 rislan rollers and 1 rubber roller to transfer fountain solution to the plate surface. I am not familiar with the gumming process, and would appreciate an explanation if you dont mind. On my press I have to manually apply ink to my water rollers during the inking up stage. As the run progresses I will see a section about 2 inches wide on the right middle side of all of my water rollers, where the ink is stripped. This same area coincides with the scumming on my plate and blanket. We are skeptical that this means that this section of the rollers aren't picking up water, and in turn the plate is drying out in that same area. With that said we are just trying to figure out what is causing our problem, and to see if we should just replace all the water rollers. So thats where we stand, we have a technician coming in on Wednesday to help shed some light on the issue, so any advice before hand would be greatly appreciated.

 

3 rislan rollers? check out this link does it look like your system?

http://therollerstore.com/rollers/lithoroll_rollers/lor_cresltine_pages/lor_4rl_cl_abd9985.htm

I assume youve either feeler gauged your damp/ink rollers or rolled through some film to check pressures? Plus drop tested ink/damp forms

If they are set correctly, do they ink up evenly before you add the water?

 

Im not sure if im correct using the term Rislan, but it just the hard rubber type roller. The system is similar to this, but its set up with the top rollers in a pyramin, with damp form roller underneeth. I have not gauged my rollers, not really sure how to do all of that. I have drop tested my form roller though, and my pressures seem correct. Everything appears fine in the inking up stage, my problem only occurs shortly into a run, appx.100 impressions.

 

Is it in the same spot as the sucker feet pick up the paper. If you use after market sucker feet they leave a residue on the paper and tranfers to your blanket causing your plate to wreck. Cure Buy original ryobi sucker feet sometime you can run without sucker feet.

 

Well guys today we had a technician could take a look at the press. As a press operator I got really good news, for my boss the news was not so good. We were told that we have to replace all rubber rollers on both heads, as well as both dampening system rollers. So after monday and $1500 my press should be in awesome shape. Thank you everyone for your insight.

 

Well there you go. Back to posting No. 9

 

I agree with the "fault-finding" technique as data suggests. BTW I'm new to this forum and I do miss printing . If anyone needs a hand, I'm available and I'm in Phoenix. Roc n Rol, JayP

 

I have a suggestion..... ever try looking for hanging dried ink on the frame spreader bars? this might be re-adding washup/ink combination back onto the rollers as you are start and stopping AND printing.... this WILL affect your roller pressures to the plate and wigglers and other rollers and "lie" to you. I just spent 4 hours on two different units on one then the sob fired me for no production...shees.

 

sounds like the press tech just might be "shotgunning" the problem. it is possible that you in fact do need new rubber all throughout your press but to suggest that your particular problem will only be cured by all new rollers is a bit of a stretch to me. If the rollers are worn or glazed you will be able to see it. glazed rollers look just that "glazed" that is to say that they look a little shiny and are usually pretty hard to the touch. Measurement with a durometer will tell you of the rollers hardness. Worn rollers will often show up as pitted. If not pitted the diameter can be measure with a caliper to see if the rubber is worn down below its service limits. Usually if its within the range of proper adjustment and makes the proper contact with the other rollers and the plate its got life left in it as long as its not pitted or of overly hard durometer. rollers are alot like the tires on a car. You can still drive on bald tires but its not advisable. Id be looking for a second opinion on the need for all new rollers to solve the particular problem you mention.

 

I'm not familiar with your machine but it doesn't really matter. I wouldn't get to caught up in worry about glaze. With most modern chemistry includeing ink and wash-up solvents it's not a huge problem. Spend your effort making certain of all roller settings and roller condition(age,hardness and defect). If wash ups are very slow it's a clue about the state your roller train is in. Don't assume any setting is correct check them all. All rubber rollers shrink and harden over time with or without use. Wash-up with a proper roller wash forget about glaze. Just trying to help hope it does.