Canon TR8660 Online Manual page 124

For A (no missing lines or no horizontal white streaks) in both the pattern C and pattern D:
The cleaning is not required. Select All A, confirm the message, then select OK.
The screen will return to the Maintenance screen.
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. Select Also B, then select Yes on the cleaning confirmation screen.
The printer starts cleaning the print head.
Cleaning the Print Head
If the pattern D or any color in the pattern C is not printed:
The cleaning is required. Select Also B, then select Yes on the cleaning confirmation screen.
The printer starts cleaning the print head.
Cleaning the Print Head
(Example: Magenta pattern is not printed)
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