Brother HL-6050DN - Manual (Page 21)

1 - 13 ABOUT THIS PRINTER
Printing on plain paper from the multi-purpose tray (MP tray)
1
Select the Paper Size, Media Type, Paper Source, and other settings in the printer driver.
Media Type: Plain Paper
Paper Source: MP Tray
PCL (standard) printer driver
BR-Script printer driver
The printer automatically turns on the MP Tray mode when you put paper in the multi-purpose tray.