Assuming your copier is connected to a switch, either monitor the traffic going to\from the copier port by using a mirror or span port on the switch, or if the switch doesn't support that, then buy a cheap one that does and insert it between the copier and the existing switch. See the Ethernet Capture wiki page, Monitor Mode section for more details.
If your copier is connected via WiFi, life is more difficult. If at all possible use a wired connection as above, else you may be able to capture traffic from the AP it it supports that. If the AP doesn't support captures, then you could buy one that does, or use a switch mirror port upstream of the AP. If you can't do anything else, then you could try to capture the traffic "over-the-air", but that's often quite difficult. see the Wiki page on WLAN Capture for more info.
Even with all the above the captures may not be illuminating as they may all be encrypted with TLS.