Canon Pixma iP90 User Manual page 57

Cleaning
Click to start Print Head Cleaning. When printing becomes faint or colors
are incorrect, cleaning the Print Heads may fix these problems.
(1) Cleaning
Perform Print Head Cleaning to unclog the Print Head Nozzles.
Select this cleaning when the print result is unsatisfactory.
See Print Head Cleaning
(2) Deep Cleaning
Perform a more thorough Print Head Cleaning to unclog the Print Head
Nozzles.
Use this function only if Cleaning has not improved the print quality.
See Print Head Deep Cleaning
(3) Bottom Plate Cleaning
Click to clean the Bottom Plate smudged during duplex printing.
See Cleaning the Inside of the Printer