It sounds like your documents are taking a long time to process on the computer before leaving to the physical printing queue on the printer. This makes me assume the problem is on the Win7 machine and is some kind of a driver conflict as opposed to some kind of physical defect or network conflict.
You can rule out a printer defect by printing reports directly from the printer. If those reports are nice and speedy then you know the problem is either on the network or the PC.
I would start the troubleshooting by switching the print driver to a UPD of a different variety than the one currently installed. UPDs come in PCL5 PCL6 and PS. Chances are the default is a PCL6 driver so I would suggest switching to a UPD PS driver, but try them all and see if you can have an impact.