ok I've been trying to get my scanner working for some time now. I have an HP PSC 750 printer and it works fine with the HPIJS driver for printing. I installed sane and the HPOJ driver, along with the USB scanner support in my kernel.

here is the lsmod line for usbcore
usbcore 62976 1 [printer uhci ehci-hcd scanner]

looks like it should work
I run ptal-init -setup and it finds my device just fine

Probe for USB-connected devices ([y]/n)? y

Probing "/dev/usb/lp0"...
Found "PSC 750xi"
with serial number "MY27MD41CZWB".

but here is the output of sane find scanner:
# No SCSI scanners found. If you expected something different, make sure that
# you have loaded a SCSI driver for your SCSI adapter.
# Also you need support for SCSI Generic (sg) in your operating system.
# If using Linux, try "modprobe sg".

# No USB scanners found. If you expected something different, make sure that
# you have loaded a driver for your USB host controller and have installed a
# kernel scanner module.

# Scanners connected to the parallel port or other proprietary ports can't be
# detected by this program.

Anybody have similar problems?

Take a look at whether you need to monkey with the sane conf file for hp, usually:

/etc/sane.d/hp.conf

There's an option at the end that you may need to comment in, depending on how your kernel is compiled:

# Uncomment the following if your scanner is connected by USB,
# but you are not using libusb
# /dev/usb/scanner0
# option connect-device

Cheers,

Finegan