Model: any Frontier lab
The Feature of the issue: A white line along with all pictures.

Probable Cause:

The source of this is the tape that you remove from the paper roll when you load new paper in the paper magazine. If you remove it quickly some of the glue remains on the paper and then gets stuck on the small rolls just before the exposure opening. After a while, you will get a coating of glue that catches fiber from the paper. 

You will have to lift the laser unit to clean the roller. 

Resume: Laser repair is not required.

A solution to this problem was given by a Shutter user of minilabhelp forum.