Thanks.

I've been able to scan with :
simple-scan hpaio:/net/photosmart_b110_series?ip=192.168.1.75

avahi-browse -rt _ipp._tcp gives:

+ enp3s0 IPv4 Photosmart B110 series [7A3864]               Internet Printer     local
= enp3s0 IPv4 Photosmart B110 series [7A3864]               Internet Printer     local
   hostname = [HP7A3864.local]
   address = [192.168.1.75]
   port = [631]
   txt = ["Scan=T" "Duplex=F" "Color=T" "note=" "adminurl=http://HP7A3864.local." "mac=9c:8e:99:7a:38:64" "priority=60" "usb_MDL=Photosmart B110 series" "usb_MFG=HP" "product=(HP Photosmart B110 series)" "ty=Photosmart B110 series" "URF=CP1,MT1-2-8-9-10-11,OB9,OFU0,PQ3-4-5,RS300-600,SRGB24,W8,IS1" "rp=ipp/printer" "pdl=application/vnd.hp-PCL,image/urf,image/jpeg" "qtotal=1" "txtvers=1"]

avahi-browse -rt _uscan._tcp gives nothing, and

scanimage -L gives:
No scanners were identified. If you were expecting something different,
check that the scanner is plugged in, turned on and detected by the
sane-find-scanner tool (if appropriate). Please read the documentation
which came with this software (README, FAQ, manpages).

I checked the scanner was well turned on. It's connected via Wifi.

sane-find-scanner gives:
  # sane-find-scanner will now attempt to detect your scanner. If the
  # result is different from what you expected, first make sure your
  # scanner is powered up and properly connected to your computer.

  # No SCSI scanners found. If you expected something different, make sure that
  # you have loaded a kernel SCSI driver for your SCSI adapter.

could not open USB device 0x1d6b/0x0003 at 004:001: Access denied (insufficient permissions)
could not open USB device 0x1d6b/0x0002 at 003:001: Access denied (insufficient permissions)
could not open USB device 0x1d6b/0x0003 at 002:001: Access denied (insufficient permissions)
could not open USB device 0x05ac/0x0221 at 001:004: Access denied (insufficient permissions)
could not open USB device 0x05ac/0x1006 at 001:003: Access denied (insufficient permissions)
could not open USB device 0x046d/0xc077 at 001:002: Access denied (insufficient permissions)
could not open USB device 0x1d6b/0x0002 at 001:001: Access denied (insufficient permissions)
  # No USB scanners found. If you expected something different, make sure that
  # you have loaded a kernel driver for your USB host controller and have setup
  # the USB system correctly. See man sane-usb for details.

  # Not checking for parallel port scanners.

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

  # You may want to run this program as root to find all devices. Once you
  # found the scanner devices, be sure to adjust access permissions as
  # necessary.

sudo sane-find-scanner gives:
  # sane-find-scanner will now attempt to detect your scanner. If the
  # result is different from what you expected, first make sure your
  # scanner is powered up and properly connected to your computer.

  # No SCSI scanners found. If you expected something different, make sure that
  # you have loaded a kernel SCSI driver for your SCSI adapter.

could not fetch string descriptor: Pipe error
could not fetch string descriptor: Pipe error
  # No USB scanners found. If you expected something different, make sure that
  # you have loaded a kernel driver for your USB host controller and have setup
  # the USB system correctly. See man sane-usb for details.

  # Not checking for parallel port scanners.

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

Cheers,

Frédéric