Hi All, We're having an issue at the moment with our grater roller marking the product. We getting heaps of little dots. We've narrowed it down to the grater roller (we call it a glassbead roller) by crash stopping the press and tracing it back. We've installed a new grater roller which actually made the marking worse so have put the old one back in. Just in case my terminology is different, the grater roller or glassbead is the last roller the wet/uncured web touches before going into the dryer/oven. We clean it every run but it appears again after 2000 copies. We're running a manroland uniset (heatset) Does anyone have any tips or solutions for this. It appears to of only become a big issue recently. Thanks Marty
Ink coverage plays a large part in allowing grater marks to track on the web. Web tension, grater bearings, grater material covering type & condition, ink / water balance, pipe roller condition, etc. all play a part in creating the tracks. Keeping it clean between runs is vital. I've used several different types of covering for those over the years and got best results with some clear material that felt like it had a lot of teflon on it. The metalized ones work ok for offset stocks. The only true way to eliminate the grater roll marks is to install an air turn system but you should be able to get it back into a fashion that you can live with. Have you changed ink recently?
