error: Unable to communicate with device (code=12):

Some times it prints, most of the time it does not. Ubuntu 14.04 64 bit. I reinstalled the latest HPLIP 3.14.10 numerous times.

Strange thing is that when I run "dpkg -l hplip", I still see the old default version 3.14.3:

# dpkg -l hplip
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/ Name Version Architecture Description
+++-==============-============-============-=================================
rc hplip 3.14.3-0ubun amd64 HP Linux Printing and Imaging Sys

Here are the diagnostics that you usually ask:

# hp-check -t
Saving output in log file: /home/bob/hp-check.log

HP Linux Imaging and Printing System (ver. 3.14.10)
Dependency/Version Check Utility ver. 15.1

Copyright (c) 2001-13 Hewlett-Packard Development Company, LP
This software comes with ABSOLUTELY NO WARRANTY.
This is free software, and you are welcome to distribute it
under certain conditions. See COPYING file for more details.

Note: hp-check can be run in three modes:
1. Compile-time check mode (-c or --compile): Use this mode before compiling the
HPLIP supplied tarball (.tar.gz or .run) to determine if the proper dependencies
are installed to successfully compile HPLIP.
2. Run-time check mode (-r or --run): Use this mode to determine if a distro
supplied package (.deb, .rpm, etc) or an already built HPLIP supplied tarball
has the proper dependencies installed to successfully run.
3. Both compile- and run-time check mode (-b or --both) (Default): This mode
will check both of the above cases (both compile- and run-time dependencies).

Check types:
a. EXTERNALDEP - External Dependencies
b. GENERALDEP - General Dependencies (required both at compile and run time)
c. COMPILEDEP - Compile time Dependencies
d. [All are run-time checks]
PYEXT SCANCONF QUEUES PERMISSION

Status Types:
    OK
    MISSING - Missing Dependency or Permission or Plug-in
    INCOMPAT - Incompatible dependency-version or Plugin-version

---------------
| SYSTEM INFO |
---------------

 Kernel: 3.13.0-38-generic #65-Ubuntu SMP Thu Oct 9 11:36:50 UTC 2014 GNU/Linux
 Host: bob-desktop
 Proc: 3.13.0-38-generic #65-Ubuntu SMP Thu Oct 9 11:36:50 UTC 2014 GNU/Linux
 Distribution: ubuntu 14.04
 Bitness: 64 bit

-----------------------
| HPLIP CONFIGURATION |
-----------------------

HPLIP-Version: HPLIP 3.14.10
HPLIP-Home: /usr/share/hplip
HPLIP-Installation: Auto installation is supported for ubuntu distro 14.04 version

Current contents of '/etc/hp/hplip.conf' file:
# hplip.conf. Generated from hplip.conf.in by configure.

[hplip]
version=3.14.10

[dirs]
home=/usr/share/hplip
run=/var/run
ppd=/usr/share/ppd/HP
ppdbase=/usr/share/ppd
doc=/usr/share/doc/hplip-3.14.10
html=/usr/share/doc/hplip-3.14.10
icon=/usr/share/applications
cupsbackend=/usr/lib/cups/backend
cupsfilter=/usr/lib/cups/filter
drv=/usr/share/cups/drv/hp
bin=/usr/bin

# Following values are determined at configure time and cannot be changed.
[configure]
network-build=yes
libusb01-build=no
pp-build=no
gui-build=yes
scanner-build=yes
fax-build=yes
dbus-build=yes
cups11-build=no
doc-build=yes
shadow-build=no
hpijs-install=no
foomatic-drv-install=no
foomatic-ppd-install=no
foomatic-rip-hplip-install=no
hpcups-install=yes
cups-drv-install=yes
cups-ppd-install=no
internal-tag=3.14.10
restricted-build=no
ui-toolkit=qt4
qt3=no
qt4=yes
policy-kit=no
lite-build=no
udev_sysfs_rules=no
hpcups-only-build=no
hpijs-only-build=no

Current contents of '/var/lib/hp/hplip.state' file:
[plugin]
installed = 1
eula = 1
version = 3.14.10

Current contents of '~/.hplip/hplip.conf' file:
[upgrade]
notify_upgrade = true
last_upgraded_time = 1413153578
pending_upgrade_time = 0
latest_available_version = 3.14.10

[settings]
systray_visible = 0
systray_messages = 0

[last_used]
device_uri = "hp:/usb/HP_LaserJet_1018?serial=KP0KEGW"
printer_name =
working_dir = .

[commands]
scan = /usr/bin/xsane -V %SANE_URI%

[refresh]
rate = 30
enable = false
type = 1

[polling]
enable = false
interval = 5
device_list =

[fax]
voice_phone =
email_address =

[installation]
date_time = 13/10/2014 08:23:02
version = 3.14.10

 <Package-name> <Package-Desc> <Required/Optional> <Min-Version> <Installed-Version> <Status> <Comment>

--------------------------
| External Dependencies |
--------------------------

 policykit Admin-Policy-framework OPTIONAL - 0.105 OK -
 gs Ghostscript REQUIRED 7.05 9.10 OK -
 network Network-wget OPTIONAL - 1.15 OK -
 scanimage Shell-Scanning OPTIONAL 1.0 1.0.23 OK -
 avahi-utils avahi-utils OPTIONAL - 0.6.31 OK -
 dbus DBus REQUIRED - 1.6.18 OK -
 cups CUPS REQUIRED 1.1 1.7.2 OK 'CUPS Scheduler is running'
 xsane SANE-GUI OPTIONAL 0.9 0.998 OK -

-------------------------
| General Dependencies |
-------------------------

 reportlab Python-PDF-Lib OPTIONAL 2.0 3.0 OK -
 libcrypto OpenSSL-Crypto-Lib REQUIRED - 1.0.1 OK -
 pil Python-Image-Lib OPTIONAL - 1.1.7 OK -
 pyqt4-dbus PyQt4-DBUS REQUIRED 4.0 4.10.4 OK -
 libjpeg JPEG-Lib REQUIRED - - OK -
 libpthread POSIX-Threads-Lib REQUIRED - 2.19 OK -
 python-dbus Python-DBUS REQUIRED 0.80.0 1.2.0 OK -
 python-devel Python-SDK REQUIRED 2.2 2.7.6 OK -
 pyqt4 Python-Qt4 REQUIRED 4.0 4.10.4 OK -
 cups-devel CUPS-SDK REQUIRED - 1.7.2 OK -
 sane-devel SANE-SDK REQUIRED - 1.0.23 OK -
 libusb USB-Lib REQUIRED - 1.0 OK -
 sane Scan-Lib REQUIRED - 1.0.23 OK -
 cups-image CUPS-Image-Lib REQUIRED - 1.7.2 OK -
 libnetsnmp-devel SNMP-Networking-SDK REQUIRED 5.0.9 5.7.2 OK -
 python-xml Python-XML-Lib REQUIRED - 2.1.0 OK -
 python-notify Desktop-notifications OPTIONAL - - OK -

------------------------------
| Compile Time Dependencies |
------------------------------

 gcc gcc-Compiler REQUIRED - 4.8.2 OK -
 libtool Build-tools REQUIRED - 2.4.2 OK -
 make GNU-Build-tools REQUIRED 3.0 3.81 OK -

----------------------
| Python Extentions |
----------------------

 cupsext CUPS-Extension REQUIRED - 3.14.10 OK -
 pcardext PhotoCard-Extension REQUIRED - 3.14.10 OK -
 hpmudext IO-Extension REQUIRED - 3.14.10 OK -

-----------------------
| Scan Configuration |
-----------------------

 hpaio HPLIP-SANE-Backend REQUIRED - 3.14.10 OK 'hpaio found in /etc/sane.d/dll.conf'
 scanext Scan-SANE-Extension REQUIRED - 3.14.10 OK -

------------------------------
| DISCOVERED SCANNER DEVICES |
------------------------------

No Scanner found.

--------------------------
| DISCOVERED USB DEVICES |
--------------------------

No devices found.

---------------------------------
| INSTALLED CUPS PRINTER QUEUES |
---------------------------------

HP_LaserJet_1018
----------------
Type: Printer
Device URI: hp:/usb/HP_LaserJet_1018?serial=KP0KEGW
PPD: /etc/cups/ppd/HP_LaserJet_1018.ppd
PPD Description: HP LaserJet 1018, hpcups 3.14.10, requires proprietary plugin
Printer status: printer HP_LaserJet_1018 is idle. enabled since Δευ 13 Οκτ 2014 08:20:1Rendering completed
Required plug-in status: Installed
error: Unable to communicate with device (code=12): hp:/usb/HP_LaserJet_1018?serial=KP0KEGW
error: Device not found
error: Communication status: Failed

--------------
| PERMISSION |
--------------

-----------
| SUMMARY |
-----------

Missing Required Dependencies
-----------------------------
None

Missing Optional Dependencies
-----------------------------
None

Total Errors: 1
Total Warnings: 0

Done.