How do I configure a local printer at /dev/lp0?

[Alan Mackenzie]

How do I configure a local printer which is connected to /dev/lp0 with a USB cable?  I'm running Gentoo Linux (up-to-date version).

I've searched the documentation on http://localhost:631, yet found not one single mention of /dev.

I know the printer works at a low level, because this works:
    # echo printing^L > /dev/lp0

I know that printing through cups works in general, since with a different variation of my system, with the printer at /dev/usb/lp0, it works adequately.

Here is my /etc/cups/printers.conf:

# Printer configuration file for CUPS v1.4.8
# Written by cupsd on 2012-04-14 10:33
# DO NOT EDIT THIS FILE WHEN CUPSD IS RUNNING
<Printer ML-1450>
Info Samsung ML-1450
Location Megaron
MakeModel Samsung ML-1450 Foomatic/pxlmono (recommended)
DeviceURI usb://Samsung/ML-1450
State Idle
StateTime 1334399599
Type 8400900
Filter application/vnd.cups-raw 0 -
Filter application/vnd.cups-postscript 0 foomatic-rip
Accepting Yes
Shared No
JobSheets none none
QuotaPeriod 0
PageLimit 0
KLimit 0
OpPolicy default
ErrorPolicy stop-printer
</Printer>

Thanks for the help!

--
Alan Mackenzie (Nuremberg, Germany).