USB problem with my printer

Hi all :))

Shortly: the USB driver detects my printer and correctly
registers and unregisters it when disconnecting the USB cable. But I'm not able to print thru USB port :((

My printer is a Lexmark Optra E312, with parallel and USB ports.
I'm able to use it thru the parallel port without problems, but when I use the USB interface, it doesn't work. I load modules 'usbcore', 'usb-uhci' and 'printer', I've created the node usblp0 (char, major 180, minor 0), but when I try to send something to the printer, using 'cat', 'echo' or even using 'pdq', the process goes to sleep forever :( I've tested three different USB cables, and my USB port seems to work.

Am I doing something wrong? Do I need to pass args to the printer
USB driver?.

Thanks in advance :)
Raúl