Solvent based Ink Sticking on Gravure Press

[bilalumer89]

Hi guys!

I wanted to know about the possible reasons why some solvent based inks stick on the sides(not having the substrate) of the impression cylinder rubber sleeve on gravure presses? This causes us problems and we have to stop the machine after every 30,000 meters of plastic film printing and clean the impression roller sleeve.

Solutions are more than welcome!

Regards
Bilal

 

[Dan Roll]

The question would be 'how is the ink getting there?'

 

[bilalumer89]

I am attaching a few images for reference. Maybe that will help.

 

[Deleted member 16349]

I am attaching a few images for reference. Maybe that will help.
View attachment 3065
View attachment 3066

I am guessing that since you are running film that substrate is quite thin. This can mean that you have contact between the gravure cylinder and the impression roller at a fairly reasonable impression pressure.

If the impression roller is old, it might also be lower in the centre region due to wear. This would also encourage contact outside the web width.

The impression roller rubber might be too soft for thin substrates.

Also too much impression pressure might be bowing the gravure and impression roller shaft causing them to tend to touch on the outside the web region.

Ink could go from the gravure cylinder to the impression roller if the surface ink on the gravure cylinder is not wiped off completely with the doctor blade.

Some ideas for you to look at.

Just to confirm. Are we talking about gravure where you print the image onto the substrate from the image in the gravure cylinder or are you using the term gravure for a coating operation where one is using an anilox roller. I have heard the term gravure being used for that process.

 

[bilalumer89]

Thank you for such a detailed reply. Just to add clarity, I am referring to direct printing on the plastic substrate from an engraved metal cylinder. I will definitely work on the points you have mentioned and try and narrow down on the most probable causes.

All the things that you mentioned are physical and machine related in nature. I was thinking if someone here could enlighten me on how the chemistry of inks could be part of the problem as well. And how we could play with the constituents of inks to get around the problem of sticking.

regards