Disable Paper Sensor Canon LBP6230/6240
Step 1: in "Devices and Printers"
Step 1 screenshot.
Step 2: left click on "Printing preferences (menu item)"
Step 2 screenshot.
Step 3: left click on "Finishing (tab item)" in "Canon LBP6230/6240 Printing Preferences"
Step 3 screenshot.
Step 4: left click on "Advanced Settings... (button)" in "Canon LBP6230/6240 Printing Preferences"
Step 4 screenshot.
Step 5: left click on "Detect Paper Size (text)" in "Advanced Settings"
Step 5 screenshot.
Step 6: left click on "Detect Paper Size: (combo box)" in "Advanced
Step 6 screenshot.
Step 7: left click on "Advanced Settings (dialog)"
Step 7 screenshot.
Step 8: left click in "Advanced Settings"
Step 8 screenshot.
Step 9: left click on "Apply (button)" in "Canon LBP6230/6240 Printing Preferences"
Step 9 screenshot.
Step 10: left click in "Canon LBP6230/6240 Printing Preferences"
Step 10 screenshot.