Canon MX720 Series Online Manual page 107

5. Examine the nozzle check pattern.
Examining the Nozzle Check Pattern
If a particular color is not printed properly, replace the ink tank of that color.
Replacing an Ink Tank
If the problem is not resolved, turn off the power and clean the print head deeply again after 24 hours. Do
not disconnect the power plug when turning off the power.
If the problem is still not resolved, the print head may be damaged. Contact the service center.
Note
To access other available functions, use the mode buttons or the MENU button.