ohhh I understand..... I need to add the chmod command in a file that runs
at boot because:

       Setting permis‐
       sions with "chmod" is not permanent... they will be reset  after
       reboot or replugging the scanner.

so then it would be to add

     chmod 770 /dev/bus/usb/*

to /etc/rc.local .
Or perhaps the kernel is claiming the scanner?

       Libusb  can  only access your scanner if it's not claimed by the
kernel
       scanner driver. If you want to use libusb,  unload  the  kernel
 driver
       (e.g. rmmod scanner under Linux) or disable the driver when
compiling a
       new kernel.