Comment 206 for bug 1728012

I have a USB-connected brother printer/scanner MFC-7420, hooked up to a desktop running xubuntu 18.04.1 The printer works but the scanner does not. I have tried pretty much every heck posted here and elsewhere but to no avail. Here's what I have done and the error messages I got. Heads up: I wonder what's the significance on the discrepency in (3) below?

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0) To install the drivers I following the instruction (+FAQ) on

https://support.brother.com/g/b/downloa ... all&os=128

including brother-udev-rule-type1-1.0.2-0.all.deb. The printer works, but not the scanner.
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1) Xsane says

Failed to open device `brother2:bus2;dev5'
Invalid argument.

(sudo xsane gives the same error message). When I fire up simple-scan (sudo or otherwise) it says

Ready to Scan
Brother MFC-7420

but when I click "scan" I got "Unable to connect to scanner".
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2) scanimage -L
device `brother2:bus2;dev5' is a Brother MFC-7420 USB scanner

scanimage --test
scanimage: open of device brother2:bus2;dev5 failed: Invalid argument
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3) lsusb
Bus 001 Device 002: ID 04f9:0180 Brother Industries, Ltd MFC-7420

[ Question: How come it says 001:002 when xsane complains about 002:005 ?!! ]

ls -l /dev/bus/usb/001/002
crw-rw-r--+ 1 root lp 189, 1 Jan 17 15:36 /dev/bus/usb/001/002

ls -l /dev/bus/usb/001
total 0
crw-rw-r-- 1 root root 189, 0 Jan 17 15:27 001
crw-rw-r--+ 1 root lp 189, 1 Jan 17 15:36 002
crw-rw-r-- 1 root root 189, 2 Jan 17 15:27 003
crw-rw-r-- 1 root root 189, 3 Jan 17 15:27 004
crw-rw-r-- 1 root root 189, 4 Jan 17 15:27 005
crw-rw-r-- 1 root root 189, 5 Jan 17 15:27 006

[Question: According to
https://cromwell-intl.com/open-source/x ... ument.html
the command above should have listed "scanner" but as you can see it's not there]
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4) I have copied files from lib64 to lib, such as
sudo ln -sf /usr/lib64/libbrscandec*.so* /usr/lib
Reboot but to no avail.
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5) I added myself to the scanner group:
sudo usermod -a -G scanner (me)
Reboot but to no avail. I also tried

more /etc/group | grep -n scanner

and here's the output:
59:scanner:x:120:saned,(me)
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6) I edited /lib/udev/rules.d/60-libsane1.rules following the heck in (#12 of)

https://easylinuxtipsproject.blogspot.c ... nters.html

Reboot but to no avail.
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7) There is no "brother.conf" in /etc/sane.d
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8) I used synaptic to delete all "brother" related files, reinstall the drivers in (step 0) above, reboot but to no avail.
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9) I added the following two lines at the end of /lib/udev/rules.d/40-libsane.rules (Before the line "# The following rule will disable ...")

# Brother scanners
ATTRS{idVendor}=="04f9", ENV{libsane_matched}="yes"

Reboot but to no avail.
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I'm at a lost on what to do. The scanner (again, it's USB-based, not wireless) worked until window, but I no longer have access to the window machine and I really need the scanner for work. Your help and advice is most welcome. THANKS!