When you see these marks, that means you ran paper through the machine that wasn't 100% dry.
You can clean the machine by using varsol to wipe down these area's:
In the paper feed section, right above the green paper feeding knobs, there is a toothed roller. Use a cloth with varsol and gently wipe down excess ink
Inside the machine, pull out the drum and access the rollers inside. Use cloth with varsol to gently wipe down ink