Canon MG2400 Series Online Manual page 97

The paper cleans the inside of the machine as it feeds through the machine.
Check the folded parts of the ejected paper. If they are smudged with ink, perform
Bottom Plate Cleaning again.
If the problem is not resolved after performing cleaning again, the protrusions inside the
machine may be stained. Clean them according to instructions.
Cleaning the Protrusions inside the Machine
Note
When performing Bottom Plate Cleaning again, be sure to use a new piece of paper.
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