Comment # 11 on bug 938659 from Johannes Meixner

Werner,
regarding your question in comment#9:
udev-configure-printer has nothing to do with this issue
(see my comment#7).

The issue is that for some USB printer models
when udev creates its device node /dev/bus/usb/<bus_number>/<device_number>
then it does not work that the device node owner/group/permissions
are set to "rw-rw-r-- root lp" (group lp with rw permissions is
needed so that the CUPS 'usb' backend that runs as user lp group lp
can communicate with the device).

Instead for some USB printer models the device node
is created with "rw-rw---- root users".

And comment#10 proves (what I always had suspected) that
the issue depends on the USB printer model because for
Markus Elfring's first USB printer Kyocera ECOSYS P6021cdn
the device node is wrongly created with "rw-rw---- root users"
while for his second USB printer Epson Stylus C84
the device node is correctly created with "rw-rw-r-- root lp".

>From my point of view the questions are now:
What is the difference between both USB printer models
that result different group and permissions for the device node
and/or what has changed in udev/systemd why for some USB printers
the device node is no longer created with "rw-rw-r-- root lp"
as it had worked all the time in the past for all USB printers.