I produced an Apple raster file, out.urf, using cupsfilter. It was sent to my HP ENVY 4520 with netcat 192.168.7.235 9100 < out.urf as a user and was immediately printed. I then did cat out.urf > /dev/usb/lp0 as root. The printer woke up and its display showed "Now printing...". A printed sheet took five minutes to be ejected from the printer. Might this be printer- and/or vendor-specific? -- Brian.