Canon LBP7780CX User Manual page 170

Select either [MP Tray Paper Type], [Drawer 1 Type] or [Drawer 2 Type].
Since the printer driver's [Paper Type] default value is [Printer Default], it is normally not necessary to change the
printer driver settings.
Whenever you change the printer driver settings, match them with the paper settings on the control panel.
5
Select the paper type with [
The paper type is registered.
Next, specify the following settings.
When printing from the printer driver on Windows or Macintosh, configure the printer
driver.
"Configuring the Printer Driver and Printing"
When printing from DOS or UNIX, specify the settings for [Standard Paper Size] and
[Default Paper Type] using the control panel.
"[Setup] Menu ([Paper Source] Options)"
] or [ ], and then press [OK].