The easiest way to determine if another system (or printer) is available on your network is to ping it. You will need to use the command line to run this command. Here's an example:
$ ping -c 5 192.168.1.105
You should also be able to look at your router to see if it sees the printer as a client.
Last important note... make sure that your printer is not setup on a DHCP setting; it should have a fixed IP address. Otherwise everytime you shut the printer down or turn off your router, the printer may acquire a different IP address on startup. This IP address may differ from what you have setup in CUPS on your Linux system.