Page 35-37 tells you how to set ip on the printer.
The printer and the pc need to be on the same subnet, which when one is wired (printer) and one is wireless(computer) this is often not the case. Also if there are multiple wireless networks one maybe on the same subnet as the wired network, but another may not be.
If you can remote login to the printer's web interface from the pcs that can't connect to it (Type ip of printer into a webrowser on the pc) they are on the same subnet. If it brings up the printer's webpage I would delete the printer and re-add it