That printer is connected to the corporate LAN, but you can't talk to it using LPR or IPP because it is hidden behind the corporate firewall. But there are a few steps here - and it gets more complicated if there is a restriction on the length of email messages which can be passed through one of the servers along the way. You will then have to perform some sort of file-split operation and send the individual parts. The people who make Brother printers thought of all this, and developed a set of Windows printer drivers. These enable users to print directly to a designated email address.
Users can also nominate an address for email confirmation.
My first stab at this was a Korn-shell program to which appropriate incoming mail items were piped via a sendmail alias. The program used 'awk' to extract information such as job and part number, then decoded each such item into an appropriately named file in a designated directory. If they had, it concatenated them in sequence, piped the result to the nominated printer, and deleted them. The components of each job stay on that server until the network card determines that all necessary parts are available, at which stage it sucks them down and decodes them in sequence, sending the output to the printer mechanism, and requests their deletion from the server. So here's how it can be done on a Linux machine.