En fait après avoir vérifier que l’impression était possible ( d’où la vérification par cups)
j’ai simplement modifié /etc/sane.d/net.conf
# This is the net backend config file.
## net backend options
# Timeout for the initial connection to saned. This will prevent the backend
# from blocking for several minutes trying to connect to an unresponsive
# saned host (network outage, host down, ...). Value in seconds.
connect_timeout = 60
## saned hosts
# Each line names a host to attach to.
# If you list "localhost" then your backends can be accessed either
# directly or through the net backend. Going through the net backend
# may be necessary to access devices that need special privileges.
localhost
192.168.0.22
j’ai provisoirement arreté le firewall
Et le scanner est détecté
root@debian:/lib/systemd/system# scanimage -L
device `pixma:MG3600_192.168.0.22' is a CANON Canon PIXMA MG3600 Series multi-function peripheral
root@debian:/lib/systemd/system#
ET Simple Scan fonctionne 
Faut que je vois ce qu’il faut ouvrir sur le firewall