I cannot tell what particular USB quirk or quirks (you can have more than one in a line) might help for your particular USB printer or if it is even hopeless to use a particular USB device with the libusb-based 'usb' backend. Because it had worked by using the usblp kernel module (i.e. with the usblp-based 'usb' backend in our CUPS 1.5.4) there is at least the workaround that I mentioned in comment#68