Canon PIXMA MG4200 Series On-Screen Manual page 142

The screen will return to the Maintenance screen.
Note
Press the HOME button to exit Setup and display the HOME screen.
For (B) (lines are missing or horizontal white streaks are present) in the pattern
(2), or in both the pattern
(1) The cleaning is required. Select Also B, then press the OK button.
The cleaning confirmation screen will appear.
(2) Select Yes, then press the OK button.
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.
(1) and pattern (2):
(1) or pattern
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