Canon LBP7780CX User Manual page 866

Connected
Unconnected
<Question 6> Check the settings for [Interface Selection].
"[Setup] Menu ([Interface] Options)"
[USB] is set to [On].
[USB] is set to [Off].
<Question 7> Can you print a test page in Windows?
"Basic Operations/Various Information for Windows"
Printable
Not printable
<Question 8> Is the port to be used selected correctly?
"Basic Operations/Various Information for Windows"
If you have another USB cable, use it.
If printing does not work, proceed to <Question 6>.
Connect the cable properly.
"Connecting to a Computer"
To <Question 7>
Set it to [On].
There is no problem with the printer and driver.
Check the printing preferences in the application.
To <Question 8>