My Phaser prints a Download Free Programs yellow line, about 0.5 inches wide, on the left edge of each page on both sides. The yellow line appears also with B&W printing.
The diagnostic shows all the consumed units are ok: Toner Cartridges, Transfer Roller, Imaging Unit and Fuser.
I performed color and margin calibrations - no cure.
It seems that the line thickness becomes wider from day to day.
Any idea about the suspected unit, or maintenance activity ?