Plate lead edge ink build up is caused by excessive form roll pressure due to too heavy of a form roll to plate setting or a loose Kompac.
The Kompac II form roll ink stripe to a dry plate should be no less that 1/8″ and no greater that 3/16″. A setting greater than 3/16″ will cause the form roll to hit the plate lead edge too hard causing a lead edge ink build up.
The Kompac III form roll ink stripe to a dry plate should be no less that 1/8″ and no greater than 5/32″. A greater setting than 5/32″ will also cause a lead edge ink build up.
A loose Kompac will also cause a lead edge ink build up on the plate.
If your Kompac ‘bounces’ as it rolls accross the plate cylinders’ opening, chances are the mounting brackets are loose or the interface between the Kompac and its’ brackets, or brackets to press are worn.
This condition allows the Kompac form roll to fall ‘into’ the plate cylinder opening where the form roller hits the lead edge of plate cylinder too hard causing a lead edge ink build up. Replace worn parts or tighten bracketry to resolve any loose condition and re-adjust form to plate setting.