Canon MB5000 Series Online Manual page 208

For B (lines are missing or horizontal white streaks are present) in the pattern C or pattern D, or
in both patterns:
The cleaning is required. Tap Also B, then tap Yes on the cleaning confirmation screen.
The machine starts cleaning the print head.
Cleaning the Print Head
Note
• The total number of sheets printed so far is shown in increments of 50 sheets on the printout of the
nozzle check pattern.
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