DCP-9020CDW

Download LPR driver.
https://download.brother.com/welcome/dlf100441/dcp9020cdwlpr-1.1.2-1.i386.deb

Login as a superuser ( or use "sudo" option if required).

Check if pre-required procedures are completed
For Debian/Ubuntu 64bit

Install the driver.

Turn on the printer and connect the usb, network or parallel cable.
Go to the directory where the driver is.
Install LPR driver.The install process may take some time. Please wait until it is complete.
Command : dpkg -i --force-all (lpr-drivername)
Check if the LPR driver is installed.
Command : dpkg -l | grep Brother

Check the configuration filename for your distribution.
Example:
openSUSE, Ubuntu, Debian : /etc/printcap
Redhat, fedora, Mandriva : /etc/printcap.local

Edit the file according to your connection.

Check if the parameter of ":lp" is ":lp=/dev/usb/lp0"

replace ":lp" line to the following 2 lines
:rm=(ip address of your printer)\
:rp=lp\

replace ":lp" line to the following line
:lp=/dev/lp0\

Command (for lpr): /etc/init.d/lpr restart
Command (for lprng) : /etc/init.d/lprng restart

Try a test print.