HP ScanJet 5590 Stops Working at 10.5.5

When I updated from 10.5.3 to 10.5.5, I lost the ability to scan from my HP ScanJet 5590 flatbed scanner. It's connected via USB. When I try to use the scanner, it correctly displays a preview window but when I try to scan an image (to Photoshop, to a PDF, directly to an HP printer) it starts but then hangs. My only recourse is to force-quit the HP ScanPro application and (sometimes) unplug the scanner. The scanner works perfectly if I plug it into a PC.

Noticed that when I updated from 10.5.3 to 10.5.5 via Software Update, one item included is called "HP Printer Drivers Update 1.1.1". Could this be part of my problem?

Please help! HP Customer Support is unable to suggest anything at this point.

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