Q: Wireless Printing/Network Issues

Here is our dillemma.   We have an iMac running on OS 10.6.8, a Lexmark X4650 wireless printer and a PC.  The iMac, PC and work computers and ipads as well as the printer all connect to our network.  I can print from the PC but I can't from the iMac.  I have reset the printers on the iMac.  I have unplugged and plugged back in the modem and router. I have pinged the printer from the iMac, and have found all of the ip addresses, on all devices the first three sets of numbers are all the same, and the last 3 digits are different on each device (printer, pc, imac).  When trying to print from the mac, I get the "unable to connect to printer", "device is busy", or "printer is off line". 

Any help of information on solutions would be grateful.

Thanks!