HP DeskJet 842C will not print with Print Quality set to "Normal Grayscale," but "Draft Grayscale" and "Normal Color" work.

In Document Print Status, the job status is "Stopped." In the Job Attributes, job-printer-state-message is "Filter failed." See attached for an extract from /var/log/cups/error_log.

If I reprint from the Document Print Status GUI, after a moment's pause, I get a dialog box saying "Print Error — There was a problem processing document…" and the name of the document.

I have deleted and re-added this printer several times with the Settings Manager → Printers GUI. The printer is an HP DeskJet 842C, which comes up as an 840C on screen. The test page works (I assume because it's in colour mode).

I am running Xubuntu. This printer worked with Xubuntu 10.04.2.

$ lsb_release -rd
Description: Ubuntu 14.04.1 LTS
Release: 14.04

hplip:
  Installed: 3.14.3-0ubuntu3.2
  Candidate: 3.14.3-0ubuntu3.2
  Version table:
 *** 3.14.3-0ubuntu3.2 0
        500 http://ca.archive.ubuntu.com/ubuntu/ trusty-updates/main amd64 Packages
        100 /var/lib/dpkg/status
     3.14.3-0ubuntu3 0
        500 http://ca.archive.ubuntu.com/ubuntu/ trusty/main amd64 Packages

cups:
  Installed: 1.7.2-0ubuntu1.2
  Candidate: 1.7.2-0ubuntu1.2
  Version table:
 *** 1.7.2-0ubuntu1.2 0
        500 http://ca.archive.ubuntu.com/ubuntu/ trusty-updates/main amd64 Packages
        500 http://security.ubuntu.com/ubuntu/ trusty-security/main amd64 Packages
        100 /var/lib/dpkg/status
     1.7.2-0ubuntu1 0
        500 http://ca.archive.ubuntu.com/ubuntu/ trusty/main amd64 Packages

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: hplip 3.14.3-0ubuntu3.2
ProcVersionSignature: Ubuntu 3.13.0-39.66-generic 3.13.11.8
Uname: Linux 3.13.0-39-generic x86_64
ApportVersion: 2.14.1-0ubuntu3.5
Architecture: amd64
CurrentDesktop: XFCE
Date: Tue Nov 25 23:33:52 2014
InstallationDate: Installed on 2011-03-27 (1339 days ago)
InstallationMedia: Xubuntu 10.04.2 "Lucid Lynx" - Release amd64 (20110215.1)
Lpstat: device for DeskJet_840C: hp:/usb/DeskJet_840C?serial=MX0CR1Y104LB
MachineType: System manufacturer System Product Name
Papersize: letter
PpdFiles: DeskJet_840C: HP Deskjet 840c, hpcups 3.14.3
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.13.0-39-generic root=UUID=78f80a62-5dce-4bc0-bef4-fc21c095ad2f ro quiet splash nomdmonddf nomdmonisw nomdmonddf nomdmonisw vt.handoff=7
SourcePackage: hplip
UpgradeStatus: Upgraded to trusty on 2014-11-13 (13 days ago)
dmi.bios.date: 09/08/2010
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: 1601
dmi.board.asset.tag: To Be Filled By O.E.M.
dmi.board.name: M4A88TD-V EVO/USB3
dmi.board.vendor: ASUSTeK Computer INC.
dmi.board.version: Rev X.0x
dmi.chassis.asset.tag: Asset-1234567890
dmi.chassis.type: 3
dmi.chassis.vendor: Chassis Manufacture
dmi.chassis.version: Chassis Version
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvr1601:bd09/08/2010:svnSystemmanufacturer:pnSystemProductName:pvrSystemVersion:rvnASUSTeKComputerINC.:rnM4A88TD-VEVO/USB3:rvrRevX.0x:cvnChassisManufacture:ct3:cvrChassisVersion:
dmi.product.name: System Product Name
dmi.product.version: System Version
dmi.sys.vendor: System manufacturer