Canon S450 User Manual page 177

I Cleaning the Print Heads
Cleaning the print heads clears the nozzles. There are two ways to clean the print heads:
normal print head cleaning and deep print head cleaning. Always execute normal print head
cleaning first. If this does not correct the problem then execute deep print head cleaning.
Note Cleaning the print heads consumes ink so clean the print heads only when
necessary.
Normal print head cleaning
Open the Printer Properties dialog box, then click the Maintenance tab.
1
Click the first (left) print head cleaning icon in the Print Head Cleaning box.
2
Using Maintenance Functions
Using the Windows 98/95 Printer Driver 177