Okidata C5500 not printing

We have an Okidata C5500 printer in our office. It has suddenly decided to stop printing. I am not able to find any diagnostic tools that can help me identify what the problem might be.

The printer will print sometimes, then other times it will not. Yesterday we reset the printer to the factor defaults and it printed all day. Today it is not printing and attempting to reset to the factory defaults does not seem to work.

Are there any updated firmwares for the printer? This is the version information provided on the web interface for the printer:

CU Firmware: C2.04
PU Firmware: 00.00.66
Network Firmware: 04.06
Web Remote: W4.05
Web Language: 01.05

I am not able to find a whole lot on the Internet. Searching for Okidata C5500 leads to a bunch of links for various Okidata printers, but rarely the C5500.

Any help would be appreciated.

Thanks