Unable to use my HP 4520 All-In-One

I am trying to use my HP printer. First I plugged it in and it showed up as a printer but I couldn't print from it. I eventually used the sudo chmod +x ./hplip-3.21.6.run successfully writing over the hplip-3.20 version that was native to 20.04.3 with ./hplip-3.21.6.run But this didn't work.

Currently, I have an HP circle in the top right menu bar but clicking it has it claim that there are "No Installed HP Devices Found".
Ubuntu 20.04 HP 4520 printer recognized by hp-setup tool, but tool hangs on step 3 As the question above, I also am able to use the HP tool and then see the printer on USB but after pressing ADD PRINTER on step 3, it goes back to the "No Installed HP Devices Found".
I went to the Driverless printing site described in the answer but am not sure if I need to do this because the prior person did not seem to have his issue solved.

Under Settings > Printer, I can find/add the printer and sometimes two entries of the printer (one appears automatically) but I can't seem to print from either one. I am a bit confused. Is there some easy fix that I am just not realizing. Thanks.

I can't seem to find my printer on the list linked to under the following question which was used to close out my prior question. How to install HPLIP on my Ubuntu to support my HP printer and/or scanner?

I am just trying to get the printer to work, I am not sure what trying to use the scanner will require. Please assist. Thanks.

Solution 1:

Get the printer to work with CUPS, browse to http://localhost:631, supply your login userid&password when prompted, click on Administration, then Add Printer.

To access the scanner, this canned answer may help:

Many device access problems can be resolved through group membership changes.

Specifically, if ls -l shows that the group permissions (the second "rwx" triplet) is "rw" (e.g."-rw-rw----"), then, adding oneself to the group that owns the device will grant rw access.

Here's how:

device="/dev/whatever"
sudo adduser $USER $(stat -c "%G" $device)

This allows you membership in the group that can rw the device, but there is one more step.

To make all your processes members of the new group, logout and login. Group memberships are set up at login time.

To create a single process in the new group (for testing, prior to logout/login):

newgrp $(stat -c "%G" $device)  

or, just type the group name. See man newgrp.