If you load a paper size that is not selected automatically, you need to specify the paper size with the control panel.
Press the [User Tools/Counter] key.
Press [Tray Paper Settings].
Select the tray for which you want to change the paper size.
Select the loaded paper size and feed direction, and then press [OK].
Press the [User Tools/Counter] key.
For details about paper sizes selected automatically, see Recommended Paper Sizes and Types.
If you want to print on paper that is selected automatically after printing on a paper size that is not selected automatically, you must return the setting to [Auto Detect]. Reload the paper, and select [Auto Detect] in step 4. The setting is returned to [Auto Detect].