Envy 4500 printer not scanning
Solution 1:
Try this: it worked for me. I have the same printer and had same issues until I used the terminal command hp-setup.
For more information https://wiki.archlinux.org/index.php/Sane#For_HP_hardware
Solution 2:
I had the same issue and the following steps resolved my issue. Setup the printer with:
hp-setup
and scan your document with:
hp-scan