Canon TS6400 Series Online Manual page 323

1687
Cause
FINE cartridge is not installed properly.
What to Do
Open the scanning unit / cover to open the ink cartridge locking cover, and then remove the FINE
cartridge.
Make sure that the FINE cartridges are compatible with this printer.
Then install the FINE cartridges again.
Press down the ink cartridge locking cover until it clicks into place.
After you install the FINE cartridge, close the scanning unit / cover.
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