It seems that older printers need to use libusb 0.1 and will fail with libusb 1.x. This is the case for HP Officejet G85. I was pulling my hairs out until I found this posting for another Linux... https://answers.launchpad.net/hplip/+question/210089 I hacked my ebuild to change the --disable-libusb01_build to --enable-libusb01_build and got my old Officejet G85 working. I suspect there should be a USE flag for this.
+ 19 Oct 2012; Daniel Pielmeier <billie@gentoo.org> hplip-3.12.10a.ebuild, + metadata.xml: + Add libusb0 use flag. This fixes bug #438870. Some old printers do not work + with libusb:1. Thanks to Ben for the report.