This post is summary of this forum post. I write it here again because that forum post is quite hard to reach from Google, so I put it here for my archive.

When setting up a printer in Arch and Manjaro, I often found a problem where cups unable to find the printer that connected in USB port. To fix this, we need to allow cups to scan and access USB port as root. We can do so by running :

sudo chmod og= /usr/lib/cups/backend/usb