Canon BJC-55 User Manual page 265

If print quality is not restored after cleaning
Perform print head deep cleaning to flush the nozzles. Print a Nozzle
Check Pattern to see if the printing quality has been restored. Repeat deep
cleaning if the problem still persists.
If print quality is not restored after deep cleaning
The ink may have run out. Replace the BJ tank and print the Nozzle Check
Pattern to see if the print quality has been restored.
If print quality is not restored after replacing the BJ tank(s)
Replace the BJ cartridge.
The print head may be worn out or the ink may have dried and ruined the
nozzles. After replacing the BJ cartridge, print a Nozzle Check Pattern to
see if the printing quality has been restored.
Note
If you will not be using the printer for an extended amount of time, leave the
BJ cartridge installed inside the printer or remove it and keep it in the Ink
Cartridge Storage Box to avoid damage.
Cleaning the Print Head
Printing a Nozzle Check Pattern
Changing or Replacing a BJ Cartridge
Problems and Solutions
Troubleshooting 265