This happened after an upgrade from Xenial to Bionic on this Barebones PC. Interestingly after an upgrade from Xenial to Bionic on a Laptop this problem did not occur. It also occurred with a clean install on another Barebones PC, but was fixed by installing package hplip. I've tried installing hplip on this PC but to no effect.
PS I don't know if the problem is with CUPS or hplip or another package.
ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: cups 2.2.7-1ubuntu2.1
ProcVersionSignature: Ubuntu 4.15.0-36.39-generic 4.15.18
Uname: Linux 4.15.0-36-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.4
Architecture: amd64
CupsErrorLog:
CurrentDesktop: ubuntu:GNOME
Date: Sat Oct 13 09:10:56 2018
InstallationDate: Installed on 2018-02-09 (245 days ago)
InstallationMedia: Ubuntu 16.04.3 LTS "Xenial Xerus" - Release amd64 (20170801)
Lpstat:
device for Deskjet_2540_series_527711_: ipp://HPD0BF9C527711.local:631/ipp/print
device for HP-Deskjet-2540-series: dnssd://Deskjet%202540%20series%20%5B527711%5D._ipp._tcp.local/?uuid=1c852a4d-b800-1f08-abcd-d0bf9c527711
device for Samsung-SCX-472x: socket://192.168.101.20:9100
Papersize: a4
PpdFiles:
Error: command ['fgrep', '-H', '*NickName', '/etc/cups/ppd/Deskjet_2540_series_527711_.ppd', '/etc/cups/ppd/Samsung-SCX-472x.ppd', '/etc/cups/ppd/HP-Deskjet-2540-series.ppd'] failed with exit code 2: grep: /etc/cups/ppd/Deskjet_2540_series_527711_.ppd: Permission denied
grep: /etc/cups/ppd/Samsung-SCX-472x.ppd: Permission denied
grep: /etc/cups/ppd/HP-Deskjet-2540-series.ppd: Permission denied
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.15.0-36-generic root=UUID=f83725aa-582a-4c36-9ad8-738122da2e0c ro quiet splash vt.handoff=1
SourcePackage: cups
UpgradeStatus: Upgraded to bionic on 2018-10-07 (5 days ago)
dmi.bios.date: 10/12/2016
dmi.bios.vendor: Intel Corp.
dmi.bios.version: PYBSWCEL.86A.0057.2016.1012.1134
dmi.board.name: NUC5CPYB
dmi.board.vendor: Intel Corporation
dmi.board.version: H61145-408
dmi.chassis.type: 3
dmi.modalias: dmi:bvnIntelCorp.:bvrPYBSWCEL.86A.0057.2016.1012.1134:bd10/12/2016:svn:pn:pvr:rvnIntelCorporation:rnNUC5CPYB:rvrH61145-408:cvn:ct3:cvr:
I forgot to say that the printer is a networked Samsung SCX-4729FD.