Ink or other material accumulates on the blankets or transfer cylinders on the outside dimensions of the paper stock being run.

Plate exposure or processing incorrect Using deletion pen hone, use in effected area and restart press. If this area stays clean plate exposure or processor is incorrect. Talk with your plate representative if problem persists.
Poor form roller settings Check rollers and reset as necessary to manufacturers spec
Form rollers oscillating on the plate Lock or shim rollers to prevent lateral movement
Fountain solution no keeping the plate background clean Check pH and conductivity. Flush, clean and refill if necessary. Make sure of any alcohol replacements
Wrong roller being used (Hickey pickers or flocked rollers) Replace with rubber rollers if necessary
Deep or uneven grain in plate Talk with your plate representative for correct plate
Calcium overload Add additional calcium removers to fountain solutions.