Ink catch up on Slip roller

[suresh ninan]

Press : Harris M1000B heatset press with 8 print units

There is ink catch up on slip rollers resulting in ink transfer problems and needs to be cleared regularly. The start up waste is also high.
Have tried several inks and fountain solutions.

Request advise on over coming it.

[jshawy]

Sounds like your dampening rollers are not hydrophilic any more. Have you tried desensitizing your chrome rollers. Also ask your suppliers for a MRC(metering roll cleaner) or deglazing product suitable for the slip and dampening roller. Where abouts on the slip roller does the ink build up?

One method of desensitizing the chrome rolls.
1. Clean with Ajax rinse with water
2. Clean with white vinegar rinse with water
3. Gum and buff dry.

Remember to drain your water tray and remove your slip and dampening roller before attempting this method.

Have fun

John

[JudP]

Press : Harris M1000B heatset press with 8 print units

There is ink catch up on slip rollers resulting in ink transfer problems and needs to be cleared regularly. The start up waste is also high.
Have tried several inks and fountain solutions.

Request advise on over coming it.

It is not uncommon for the slip roller to have some ink buildup on it while running however this should be minimal and should definitely not effect print quality or make ready waste.

As John said it may very well be that your rollers need to be cleaned and deglazed however from my experience it sounds like you are running too much ink and too much water. Try dropping everything down.

Best, Jud

[suresh ninan]

Thankyou for the advise. Kindly note that I have tried deglazing. Various inking and dampening levels have been tried.However once again lower inking and dampening level will be tried. The ink catch up is across the roller . It increases over a period of time and finally will have to be cleared.There are couple of points that I forgot to mention
1. it has duotrol dampening system
2. we don't use alcohol
3. we are using Sun universal heatset ink and the fount is HS 127 from D S Chemicals. Earlier we had tried Flint ink.

THe start up waste is also high

[BeauchampT]

What does the buildup look like? Is it ink only or does it have any green-grey colour to it?

Alot of ink companies are starting to put filler in their product to keep costs down - it creates alot of back track into your fount, and is purely an indication that the ink is unstable. Any 'solutions' you might come up with in this case are only temporary.

Another way to be sure of this is to look at your solid patches (assuming you have a control strip) under a microscope or good magnifier and see if you have very irregular voids in them (perfect circles is usually emulsified water drops, but the irregular shape indicates a hydrophilic filler).

[APP]

Without knowing more about your operation like are the fountain tanks temperature controlled ? Do you add only fount to the water or is there something else?
I will agree with a lot of the other comments and just add that possibly the fount being used is contributing to the issue. There are founts available tat have very little content to over emulsify ink and will allow you to reduce the water speeds on press.
Also a fount balanced out with certain nitrates and other buffering materials will definetly help.

Rick

[Alois Senefelder]

Suresh,

I suggest you read the PDFs I have posted.

Thread: Web Offset Newsletter
Date: 10 - 24 - 2009


Regards, Alois