can't scan with my m180nw

I have an HP laserjet pro mfp m180nw. I am running ubuntu 16.04. I have installed the lastest hplip, when I tried to install the printer I get an error that the printer, on the network, can't be found. so (I know you aren't supposed to do this but tried it anyway) I modified the models.dat file to change the name of a similar printer to the string returned by mine. so now, I can print, but still can't find the scanner. here is the hp-check output:
-------------------
jr@jr-Inspiron-560:/etc/cups/ppd$ hp-check -t
Saving output in log file: /etc/cups/ppd/hp-check.log

HP Linux Imaging and Printing System (ver. 3.17.11)
Dependency/Version Check Utility ver. 15.1

Copyright (c) 2001-15 HP 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: 4.10.0-42-generic #46~16.04.1-Ubuntu SMP Mon Dec 4 15:57:59 UTC 2017 GNU/Linux
 Host: jr-Inspiron-560
 Proc: 4.10.0-42-generic #46~16.04.1-Ubuntu SMP Mon Dec 4 15:57:59 UTC 2017 GNU/Linux
 Distribution: ubuntu 16.04
 Bitness: 64 bit

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

HPLIP-Version: HPLIP 3.17.11
HPLIP-Home: /usr/share/hplip
HPLIP-Installation: Auto installation is supported for ubuntu distro 16.04 version

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

[hplip]
version=3.17.11

[dirs]
home=/usr/share/hplip
run=/var/run
ppd=/usr/share/ppd/hplip/HP
ppdbase=/usr/share/ppd/hplip
doc=/usr/share/doc/hplip-3.17.11
html=/usr/share/doc/hplip-3.17.11
icon=/usr/share/applications
cupsbackend=/usr/lib/cups/backend
cupsfilter=/usr/lib/cups/filter
drv=/usr/share/cups/drv/hp
bin=/usr/bin
apparmor=/etc/apparmor.d
# 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=3.17.11
restricted-build=no
ui-toolkit=qt4
qt3=no
qt4=yes
qt5=no
policy-kit=no
lite-build=no
udev_sysfs_rules=no
hpcups-only-build=no
hpijs-only-build=no
apparmor_build=yes
class-driver=no

Current contents of '/var/lib/hp/hplip.state' file:
[plugin]
installed = 1
eula = 1
version = 3.17.11

Current contents of '~/.hplip/hplip.conf' file:
[upgrade]
notify_upgrade = true
last_upgraded_time = 1513001672
pending_upgrade_time = 0
latest_available_version = 3.17.10

[installation]
date_time = 12/14/17 13:00:25
version = 3.17.11

[settings]
systray_visible = 0
systray_messages = 0

[last_used]
device_uri = "hp:/net/HP_ColorLaserJet_MFP_M178-M181?ip=192.168.0.101"
printer_name =
working_dir = .

[commands]
scan = /usr/bin/simple-scan %SANE_URI%

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

[polling]
enable = false
interval = 5
device_list =

[fax]
voice_phone =
email_address =

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

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

 scanimage scanimage - Shell scanning program OPTIONAL 1.0 1.0.25 OK -
 policykit PolicyKit - Administrative policy framework OPTIONAL - 0.105 OK -
 gs GhostScript - PostScript and PDF language interpreter and previewer REQUIRED 7.05 9.18 OK -
 cups CUPS - Common Unix Printing System REQUIRED 1.1 2.1.3 OK 'CUPS Scheduler is running'
 avahi-utils avahi-utils OPTIONAL - 0.6.32 OK -
 dbus DBus - Message bus system REQUIRED - 1.10.6 OK -
 xsane xsane - Graphical scanner frontend for SANE OPTIONAL 0.9 0.999 OK -
 network network -wget OPTIONAL - 1.17.1 OK -

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

 python3-pil PIL - Python Imaging Library (required for commandline scanning with hp-scan) OPTIONAL - 1.1.7 OK -
 sane-devel SANE - Scanning library development files REQUIRED - 1.0.25 OK -
 python3-xml Python XML libraries REQUIRED - 2.1.0 OK -
 libjpeg libjpeg - JPEG library REQUIRED - - OK -
 cups-image CUPS image - CUPS image development files REQUIRED - 2.1.3 OK -
 python3-notify2 Python libnotify - Python bindings for the libnotify Desktop notifications OPTIONAL - - OK -
 libnetsnmp-devel libnetsnmp-devel - SNMP networking library development files REQUIRED 5.0.9 5.7.3 OK -
 python3-dbus Python DBus - Python bindings for DBus REQUIRED 0.80.0 1.2.0 OK -
 python3-reportlab Reportlab - PDF library for Python OPTIONAL 2.0 3.3.0 OK -
 python3X Python 2.2 or greater - Python programming language REQUIRED 2.2 3.5.2 OK -
 libcrypto libcrypto - OpenSSL cryptographic library REQUIRED - 1.0.2 OK -
 cups-devel CUPS devel- Common Unix Printing System development files REQUIRED - 2.1.3 OK -
 python3-pyqt4 PyQt 4- Qt interface for Python (for Qt version 4.x) REQUIRED 4.0 4.11.4 OK -
 python3-pyqt4-dbus PyQt 4 DBus - DBus Support for PyQt4 OPTIONAL 4.0 4.11.4 OK -
 sane SANE - Scanning library REQUIRED - 1.0.25 OK -
 libusb libusb - USB library REQUIRED - 1.0 OK -
 python3-devel Python devel - Python development files REQUIRED 2.2 3.5.2 OK -
 libpthread libpthread - POSIX threads library REQUIRED - b'2.23' OK -

---------------
| COMPILEDEP |
---------------

 gcc gcc - GNU Project C and C++ Compiler REQUIRED - 5.4.0 OK -
 make make - GNU make utility to maintain groups of programs REQUIRED 3.0 4.1 OK -
 libtool libtool - Library building support services REQUIRED - 2.4.6 OK -

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

 cupsext CUPS-Extension REQUIRED - 3.17.11 OK -
 hpmudext IO-Extension REQUIRED - 3.17.11 OK -

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

 scanext Scan-SANE-Extension REQUIRED - 3.17.11 OK -
 hpaio HPLIP-SANE-Backend REQUIRED - 3.17.11 OK 'hpaio found in /etc/sane.d/dll.conf'

-----------------------
| Other Dependencies |
-----------------------

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

device `hpaio:/net/HP_ColorLaserJet_MFP_M178-M181?ip=192.168.0.101' is a Hewlett-Packard HP_ColorLaserJet_MFP_M178-M181 all-in-one

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

No devices found.

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

HP_ColorLaserJet_MFP_M178-M181
------------------------------
Type: Printer
Device URI: hp:/net/HP_ColorLaserJet_MFP_M178-M181?ip=192.168.0.101
PPD: /etc/cups/ppd/HP_ColorLaserJet_MFP_M178-M181.ppd
warning: Failed to read /etc/cups/ppd/HP_ColorLaserJet_MFP_M178-M181.ppd ppd file
PPD Description:
Printer status: printer HP_ColorLaserJet_MFP_M178-M181 is idle. enabled since Thu 14 Dec 2017 11:42:27 AM EST
Required plug-in status: Installed
Communication status: Good

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

No errors or warnings.

Done.
--------------------------------
as you can see, hpcheck finds the scanner. but simple scan doesn't.

this same behavior occurs when I install the printer with the ubuntu setup, installing the printer as "generic".

any clues would be helpful, thanks.