Windows 2008 R2 Standard: Spoolsv.exe process hitting 100% CPU Usage

Server OS: Windows 2008 R2 Standard
Function: Primary Domain Controller and also Print Server
Clients: All are running Windows 7 Pro 64-Bit SP1

Roughly for the past 12 months our Print Server has routinely at (seemingly) random intervals caused the Spoolsv.exe process to hit 100% CPU Usage.

The problem can occur when:

1. We have a paper jam on a particular printer.
2. When a tray runs out of paper.
3. A particularly large PDF is printed.

Usually it's caused by a paper jam or no paper in the expected tray.

Strangely some printers have never caused the Spoolsv.exe process to hit 100% CPU (across the same model) and some often do. There's nothing different between them and the problem isn't related to a specific printer model.

We can also go weeks without this problem occuring, then have it occur several times a week. It certainly occurs every month though.

All our printers are Hewlett Packard covering models: LaserJet 4050, 4100, 4250, 4350, M4345, P4015, P4515 and Colour LaserJet 4650. Roughly a third of the printers are using HP's Universal print driver v5.3.1, a third are on v5.4 and a third v5.8 (was the newest version up until recently) because we've been going down the path that it's a version specific problem and are still testing these versions.

All these versions have been in use when the server has hit 100% CPU usuage at one time or another. Leading us to think the problem isn't print driver related!

We also have a Kyocera 300ci, a Kyocera 5500i and two Kyocera 3050ci photocopiers also on the Print Server too. These never cause the CPU to reach 100% CPU.

Things we've tried:

1. Stopping/Restarting the Print Spooler and also restarting the Server itself.
2. Deleting all SPOOL files in: C:\WINDOWS\system32\spool\PRINTERS.
3. Different printer driver versions (see above).
4. All three HP Universal drivers (5.3.1, 5.4, 5.8) are running with Full Print Driver Isolation selected (so each runs in it's own Print Isolation Host). This hasn't prevented the problem occuring.
5. Confirming the C:\WINDOWS\system32\spool folder (and subfolders) are in our McAfee VirusScan Exception list.
6. Looking in the Event Logs, which only ever details (SYSTEM Event Log):

"A timeout (30000 milliseconds) was reached while waiting for a transaction response from the Spooler service."

Any assistance would be appreciated.

Alex