I have a HP 2540 printer that worked correctly in 18.04 but not in 20.04.
I tried to install HPLIP from Hp (version 3.20.9) but got the next warnings and errors:
warning: Missing REQUIRED dependency: pyqt5 (PyQt 5- Qt interface for Python (for Qt version 4.x)) warning: Missing OPTIONAL dependency for option 'gui_qt5': pyqt5-dbus (PyQt 5 DBus - DBus Support for PyQt5) warning: Missing OPTIONAL dependency for option 'gui_qt5': python-notify (Python libnotify - Python bindings for the libnotify Desktop notifications) warning: Missing OPTIONAL dependency for option 'fax': reportlab (Reportlab - PDF library for Python) warning: Missing OPTIONAL dependency for option 'scan': pil (PIL - Python Imaging Library (required for commandline scanning with hp-scan)) warning: This installer cannot install 'pil' for your distro/OS and/or version. error: Package install command failed with error code 100
Then I uninstall HPLIP, as this answer suggest How to install latest HPLIP on my Ubuntu to support my HP printer and/or scanner? and install hp-plugin without success. The printer is added but it appears as busy or "Device communication error"
Also the scan doesn't work.
I don't know how to process now.