Shows you have poor wireless signal so maybe it's not getting the file fast on wifi
Validate Windows is not using the class driver by going to the usb pc, finding the printer, right clicking the printer(windows 7) clicking printer properties->advanced and looking at what driver is in use.
Six pages on duplex from small pdf file is about 5 minutes to finish with looong pauses between sheets. Tested on two computers, via USB and via WiFi. Installed from CD and later from web with updated drivers, but result was the same painfully long printing time. Please help me, what am I missing?