ここでも同じ問題が発生しました。時には動作し、次のチェック中にエラーメッセージで停止することがあります。

[bjnp] bjnp_open_tcp: ERROR - Can not connect to scanner: Connection refused
scanimage: sane_read: Invalid argument

# ss  -tulpn | grep :6566
tcp     LISTEN   0        128                    *:6566                 *:*      users:(("systemd",pid=1,fd=160)) 

たくさん試してみました：

• systemctlを介して無効、有効、停止、開始、および再起動。
• aptによるクリーンアップ、削除、インストール、再インストール。
• dpkg-reconfigureで再構成します。
• 最新のバックエンドをダウンロード、コンパイル、インストールします。

systemctl 精神停止

# saned -d -a saned
[saned] saned (AF-indep+IPv6) from sane-backends 1.0.27 starting up
[saned] do_bindings: [0] bind failed: Address already in use
[saned] Now daemonized

# systemctl disable saned.socket 
Removed /etc/systemd/system/sockets.target.wants/saned.socket.
# saned -d -a saned
[saned] saned (AF-indep+IPv6) from sane-backends 1.0.27 starting up
[saned] do_bindings: [1] bind failed: Address already in use
[saned] do_bindings: [0] bind failed: Address already in use
[saned] do_bindings: couldn't bind an address. Exiting.
[saned] FATAL ERROR; bailing out, waiting for children...
[saned] bail_out: all children exited
# ps ax | grep inet
23794 pts/7    S+     0:00 grep inet
32284 ?        Ss     0:01 /usr/sbin/inetd
# kill 32284
# ps ax | grep inet
23961 pts/7    S+     0:00 grep inet
# saned -d -a saned
[saned] saned (AF-indep+IPv6) from sane-backends 1.0.27 starting up
[saned] do_bindings: [1] bind failed: Address already in use
[saned] do_bindings: [0] bind failed: Address already in use
[saned] do_bindings: couldn't bind an address. Exiting.
[saned] FATAL ERROR; bailing out, waiting for children...
[saned] bail_out: all children exited
# systemctl enable saned
saned.service is not a native service, redirecting to systemd-sysv-install.
Executing: /lib/systemd/systemd-sysv-install enable saned
# systemctl disable saned
saned.service is not a native service, redirecting to systemd-sysv-install.
Executing: /lib/systemd/systemd-sysv-install disable saned
# systemctl enable saned.socket 
Created symlink /etc/systemd/system/sockets.target.wants/saned.socket → /etc/systemd/system/saned.socket.
# systemctl start  saned.socket 
Job for saned.socket failed.
See "systemctl status saned.socket" and "journalctl -xe" for details.
# systemctl status saned.socket
● saned.socket - saned incoming socket
   Loaded: loaded (/etc/systemd/system/saned.socket; enabled; vendor preset: enabled)
   Active: failed (Result: resources)
   Listen: [::]:6566 (Stream)
 Accepted: 0; Connected: 0;

Mai 12 09:29:41 monster systemd[1]: saned.socket: Failed to receive listening socket ([::]:6566): Input/output error
Mai 12 09:29:41 monster systemd[1]: saned.socket: Failed to listen on sockets: Input/output error
Mai 12 09:29:41 monster systemd[1]: saned.socket: Failed with result 'resources'.
Mai 12 09:29:41 monster systemd[1]: Failed to listen on saned incoming socket.

# ss  -tulpn | grep :6566
tcp     LISTEN   0        1                      *:6566                 *:*      users:(("saned",pid=22068,fd=3)) 

このコマンドをrootとして実行している間、他の端末から通常のユーザーとしてscanimageを使用してスキャンしようとしました。

今、いくつかのプロセスが完了するのを待ってから再起動してください。

削除してもう一度作業しました。すべてsane-airscanに関連しています。 apt purge sane-airscan、systemctl stop saned.service＆​​をsystemctl stop saned.socket押してから次を削除します。

• /etc/defaults/sane
• /etc/init.d/saned
• /lib/systemd/system/saned.socket
• /lib/systemd/system/saned.service

再起動後、次のようにインストールしました。

wget https://download.opensuse.org/repositories/home:/pzz/xUbuntu_18.04/amd64/sane-airscan_0.99.27-1+89.1_amd64.deb
dpkg -i sane-airscan_0.99.27-1+89.1_amd64.deb

root@laptop:~# export SANE_DEBUG_DLL=255 && scanimage -L 
[sanei_debug] Setting debug level of dll to 255.
[dll] sane_init: SANE dll backend version 1.0.13 from sane-backends 1.0.27
[dll] sane_init/read_dlld: attempting to open directory `./dll.d'
[dll] sane_init/read_dlld: attempting to open directory `/etc/sane.d/dll.d'
[dll] sane_init/read_dlld: using config directory `/etc/sane.d/dll.d'
[dll] sane_init/read_dlld: considering /etc/sane.d/dll.d/airscan
[dll] sane_init/read_config: reading dll.d/airscan
[dll] add_backend: adding backend `airscan'
[dll] sane_init/read_dlld: considering /etc/sane.d/dll.d/hplip
[dll] sane_init/read_config: reading dll.d/hplip
[dll] add_backend: adding backend `hpaio'
[dll] sane_init/read_dlld: done.
[dll] sane_init/read_config: reading dll.conf
[dll] add_backend: adding backend `net'
[dll] add_backend: adding backend `abaton'
[dll] add_backend: adding backend `agfafocus'
[dll] add_backend: adding backend `apple'
[dll] add_backend: adding backend `avision'
[dll] add_backend: adding backend `artec'
[dll] add_backend: adding backend `artec_eplus48u'
[dll] add_backend: adding backend `as6e'
[dll] add_backend: adding backend `bh'
[dll] add_backend: adding backend `canon'
[dll] add_backend: adding backend `canon630u'
[dll] add_backend: adding backend `canon_dr'
[dll] add_backend: adding backend `cardscan'
[dll] add_backend: adding backend `coolscan'
[dll] add_backend: adding backend `coolscan3'
[dll] add_backend: adding backend `dell1600n_net'
[dll] add_backend: adding backend `dmc'
[dll] add_backend: adding backend `epjitsu'
[dll] add_backend: adding backend `epson2'
[dll] add_backend: adding backend `epsonds'
[dll] add_backend: adding backend `fujitsu'
[dll] add_backend: adding backend `genesys'
[dll] add_backend: adding backend `gt68xx'
[dll] add_backend: adding backend `hp'
[dll] add_backend: adding backend `hp3900'
[dll] add_backend: adding backend `hpsj5s'
[dll] add_backend: adding backend `hp3500'
[dll] add_backend: adding backend `hp4200'
[dll] add_backend: adding backend `hp5400'
[dll] add_backend: adding backend `hp5590'
[dll] add_backend: adding backend `hpljm1005'
[dll] add_backend: adding backend `hs2p'
[dll] add_backend: adding backend `ibm'
[dll] add_backend: adding backend `kodak'
[dll] add_backend: adding backend `kodakaio'
[dll] add_backend: adding backend `kvs1025'
[dll] add_backend: adding backend `kvs20xx'
[dll] add_backend: adding backend `leo'
[dll] add_backend: adding backend `lexmark'
[dll] add_backend: adding backend `ma1509'
[dll] add_backend: adding backend `magicolor'
[dll] add_backend: adding backend `matsushita'
[dll] add_backend: adding backend `microtek'
[dll] add_backend: adding backend `microtek2'
[dll] add_backend: adding backend `mustek'
[dll] add_backend: adding backend `mustek_usb'
[dll] add_backend: adding backend `mustek_usb2'
[dll] add_backend: adding backend `nec'
[dll] add_backend: adding backend `niash'
[dll] add_backend: adding backend `pie'
[dll] add_backend: adding backend `pint'
[dll] add_backend: adding backend `pixma'
[dll] add_backend: adding backend `plustek'
[dll] add_backend: adding backend `qcam'
[dll] add_backend: adding backend `ricoh'
[dll] add_backend: adding backend `rts8891'
[dll] add_backend: adding backend `s9036'
[dll] add_backend: adding backend `sceptre'
[dll] add_backend: adding backend `sharp'
[dll] add_backend: adding backend `sm3600'
[dll] add_backend: adding backend `sm3840'
[dll] add_backend: adding backend `snapscan'
[dll] add_backend: adding backend `sp15c'
[dll] add_backend: adding backend `tamarack'
[dll] add_backend: adding backend `teco1'
[dll] add_backend: adding backend `teco2'
[dll] add_backend: adding backend `teco3'
[dll] add_backend: adding backend `u12'
[dll] add_backend: adding backend `umax'
[dll] add_backend: adding backend `umax1220u'
[dll] add_backend: adding backend `v4l'
[dll] add_backend: adding backend `xerox_mfp'
[dll] sane_get_devices
[dll] load: searching backend `xerox_mfp' in `/usr/lib/x86_64-linux-gnu/sane:/usr/lib/sane:/usr/lib64/sane'
[dll] load: trying to load `/usr/lib/x86_64-linux-gnu/sane/libsane-xerox_mfp.so.1'
[dll] load: dlopen()ing `/usr/lib/x86_64-linux-gnu/sane/libsane-xerox_mfp.so.1'
...
[dll] load: dlopen()ing `/usr/lib/x86_64-linux-gnu/sane/libsane-agfafocus.so.1'
[dll] init: initializing backend `agfafocus'
[dll] init: backend `agfafocus' is version 1.0.0
[dll] load: searching backend `abaton' in `/usr/lib/x86_64-linux-gnu/sane:/usr/lib/sane:/usr/lib64/sane'
[dll] load: trying to load `/usr/lib/x86_64-linux-gnu/sane/libsane-abaton.so.1'
[dll] load: dlopen()ing `/usr/lib/x86_64-linux-gnu/sane/libsane-abaton.so.1'
[dll] init: initializing backend `abaton'
[dll] init: backend `abaton' is version 1.0.0
[dll] load: searching backend `net' in `/usr/lib/x86_64-linux-gnu/sane:/usr/lib/sane:/usr/lib64/sane'
[dll] load: trying to load `/usr/lib/x86_64-linux-gnu/sane/libsane-net.so.1'
[dll] load: dlopen()ing `/usr/lib/x86_64-linux-gnu/sane/libsane-net.so.1'
[dll] init: initializing backend `net'
[dll] init: backend `net' is version 1.0.27
[dll] load: searching backend `hpaio' in `/usr/lib/x86_64-linux-gnu/sane:/usr/lib/sane:/usr/lib64/sane'
[dll] load: trying to load `/usr/lib/x86_64-linux-gnu/sane/libsane-hpaio.so.1'
[dll] load: dlopen()ing `/usr/lib/x86_64-linux-gnu/sane/libsane-hpaio.so.1'
[dll] init: initializing backend `hpaio'
[dll] init: backend `hpaio' is version 1.0.0
[dll] load: searching backend `airscan' in `/usr/lib/x86_64-linux-gnu/sane:/usr/lib/sane:/usr/lib64/sane'
[dll] load: trying to load `/usr/lib/x86_64-linux-gnu/sane/libsane-airscan.so.1'
[dll] load: dlopen()ing `/usr/lib/x86_64-linux-gnu/sane/libsane-airscan.so.1'
[dll] init: initializing backend `airscan'
[dll] init: backend `airscan' is version 1.0.0
[dll] sane_get_devices: found 1 devices
device `airscan:w0:Dell C1765nf Color MFP' is a WSD Dell C1765nf Color MFP ip=192.168.2.16
[dll] sane_exit: exiting
[dll] sane_exit: calling backend `xerox_mfp's exit function
[dll] sane_exit: calling backend `umax1220u's exit function
[dll] sane_exit: calling backend `umax's exit function
[dll] sane_exit: calling backend `u12's exit function
[dll] sane_exit: calling backend `teco3's exit function
[dll] sane_exit: calling backend `teco2's exit function
[dll] sane_exit: calling backend `teco1's exit function
[dll] sane_exit: calling backend `tamarack's exit function
[dll] sane_exit: calling backend `sp15c's exit function
[dll] sane_exit: calling backend `snapscan's exit function
[dll] sane_exit: calling backend `sm3840's exit function
[dll] sane_exit: calling backend `sm3600's exit function
[dll] sane_exit: calling backend `sharp's exit function
[dll] sane_exit: calling backend `sceptre's exit function
[dll] sane_exit: calling backend `s9036's exit function
[dll] sane_exit: calling backend `rts8891's exit function
[dll] sane_exit: calling backend `ricoh's exit function
[dll] sane_exit: calling backend `qcam's exit function
[dll] sane_exit: calling backend `plustek's exit function
[dll] sane_exit: calling backend `pixma's exit function
[dll] sane_exit: calling backend `pie's exit function
[dll] sane_exit: calling backend `niash's exit function
[dll] sane_exit: calling backend `nec's exit function
[dll] sane_exit: calling backend `mustek_usb2's exit function
[dll] sane_exit: calling backend `mustek_usb's exit function
[dll] sane_exit: calling backend `mustek's exit function
[dll] sane_exit: calling backend `microtek2's exit function
[dll] sane_exit: calling backend `microtek's exit function
[dll] sane_exit: calling backend `matsushita's exit function
[dll] sane_exit: calling backend `magicolor's exit function
[dll] sane_exit: calling backend `ma1509's exit function
[dll] sane_exit: calling backend `lexmark's exit function
[dll] sane_exit: calling backend `leo's exit function
[dll] sane_exit: calling backend `kvs20xx's exit function
[dll] sane_exit: calling backend `kvs1025's exit function
[dll] sane_exit: calling backend `kodakaio's exit function
[dll] sane_exit: calling backend `kodak's exit function
[dll] sane_exit: calling backend `ibm's exit function
[dll] sane_exit: calling backend `hs2p's exit function
[dll] sane_exit: calling backend `hpljm1005's exit function
[dll] sane_exit: calling backend `hp5590's exit function
[dll] sane_exit: calling backend `hp5400's exit function
[dll] sane_exit: calling backend `hp4200's exit function
[dll] sane_exit: calling backend `hp3500's exit function
[dll] sane_exit: calling backend `hpsj5s's exit function
[dll] sane_exit: calling backend `hp3900's exit function
[dll] sane_exit: calling backend `hp's exit function
[dll] sane_exit: calling backend `gt68xx's exit function
[dll] sane_exit: calling backend `genesys's exit function
[dll] sane_exit: calling backend `fujitsu's exit function
[dll] sane_exit: calling backend `epsonds's exit function
[dll] sane_exit: calling backend `epson2's exit function
[dll] sane_exit: calling backend `epjitsu's exit function
[dll] sane_exit: calling backend `dmc's exit function
[dll] sane_exit: calling backend `dell1600n_net's exit function
[dll] sane_exit: calling backend `coolscan3's exit function
[dll] sane_exit: calling backend `coolscan's exit function
[dll] sane_exit: calling backend `cardscan's exit function
[dll] sane_exit: calling backend `canon_dr's exit function
[dll] sane_exit: calling backend `canon630u's exit function
[dll] sane_exit: calling backend `canon's exit function
[dll] sane_exit: calling backend `bh's exit function
[dll] sane_exit: calling backend `artec_eplus48u's exit function
[dll] sane_exit: calling backend `artec's exit function
[dll] sane_exit: calling backend `avision's exit function
[dll] sane_exit: calling backend `apple's exit function
[dll] sane_exit: calling backend `agfafocus's exit function
[dll] sane_exit: calling backend `abaton's exit function
[dll] sane_exit: calling backend `net's exit function
[dll] sane_exit: calling backend `hpaio's exit function
[dll] sane_exit: calling backend `airscan's exit function
[dll] sane_exit: finished

ご覧のとおり、DellオールインワンPCが見つかりました。 device airscan:w0:Dell C1765nf Color MFP' is a WSD Dell C1765nf Color MFP ip=192.168.2.16