Plate Scratches

Has anyone seen an ink scratch a litho plate. The scratches are pencil line thin and run across the sheet in feed/delivery direction of press. The press (has happened on two) is a Heidelberg and the plates are Fuji. Problem seems to come and go; can be fixed with a plate sratch repair but later comes back in another area or in another color.

 

Are you sure that these lines are due to ink?
Is this happening on all units or on a particular one and any particular ink.
What press is this?
If it is the poorly ground ink then 1st thing that you will notice is the lines on ink fountain roller.

 

id suggest checking all your ink form rollers along with your water form roller for any kind of foreign matter that might cause abrasion on the plate. Would you by any chance be cutting down plates in house from a larger size? Ive seen non factory plate edges flake off when cut down before mounting on press.

 

foreign material imbedded in one or all of the form rollers, yup seen it a few times.