What is it?
lexbces.exe is an application included with the software and driver installation of certain lexmark network ready printers.

What does it do?
The application provides configuration of the internal network interface card that is included with lexmark network ready printers.

More info
At the time of this writing lexbces.exe is not associated with any malware
You will want to keep an eye on this google search. Watch for any association of lexbces.exe with viruses adware and spyware.