I have this model producing the same smudge marks down the left hand side of the prints. It not every sheet but intermitently through a run. I have already replaced the transfer unit as suspected that initially but still there.
Any other ideas please.
What am I looking at here? Did you delete all the content from the job with exception to the green bar and the word Cannon so that we only see the defects mid page left side?
Typically a defect will occur at equal intervals dependant on the damaged location.
3.2 inches / 82.3 mm is the fuser
3 inches / 75.3 mm is the drum for the affected color
1.1 inches / 28.3 mm is the Imaging unit
1 inch / 25.1 mm is the transfer belt
If copies but not prints there is something on the glass
If DFE only, it is the Blue, Platten only is the Red
If yours appears random, it can't be something replaceable, it would have to be contamination, in that case you would need to dig around internally to find a clump of toner/toners that somehow ended up inside the machine.
I can't display all the content of the letter as it confidential. IF you look down the left hand side you are getting the 3 colours all equidistant apart and corresponds to the distance between the drums.
Disregard the green at the bottom as that part of the header of the letter.
I have changed the transfer unit and the drums to no fix. I'm now advised that it could be the MCU which is now on order. Any other ideas would be good.
It happens on random prints, and not every time and only down the left hand side of the prints for about 10mm in. Rest of the image is good and clean.