Translation guide
The device used to send and receive faxes. In Japanese, the most common term is ファックス, which can refer to both the machine and the document. For clarity, ファクシミリ is more formal, and ファックス機 explicitly means the machine.
fax machine
Most common term; can also mean fax document.
Referring to the physical fax machine.
The most common and casual term. Can also mean a fax document, but context usually makes it clear.
ファックスが壊れた。
The fax machine broke.
I bought a new fax machine.
Explicitly means 'fax machine'. Used when you need to distinguish the machine from the document.
The fax machine is acting up.
Formal or technical term. Often used in business settings or manuals.
We installed a fax machine.