Canon LBP6780x Manual page 438

[Use RAW Printing]
[Use Bidirectional
Communication]
(3) Click [OK].
Proceed to Step
IPP/IPPS Settings
(1) Click [Edit...] in [IPP Print Settings].
When the check box is selected, the RAW printing function is enabled.
When the check box is selected, bidirectional communication is performed.
6 if you do not specify the settings for the other options.