Someone PM'd this to me when I had a visioneer paperport 3100b not working under win2k (parallel port as well), never tried it because I got a new scanner (HP by the way, never will I get a visioneer again :/ , poor support IMO)
MS Support for printers
HP LaserJet 5L Family Printers Do Not Enter Sleep Mode
HP LaserJet 5L Family Printers Do Not Enter Sleep Mode
The information in this article applies to:
Microsoft Windows XP Home Edition
Microsoft Windows XP Professional
Microsoft Windows NT Workstation 4.0
Microsoft Windows NT Server 4.0
Symptoms
When you upgrade a computer that is running Microsoft Windows 2000 to Microsoft Windows XP Hewlett-Packard (HP) LaserJet 5L family printers may not enter Sleep mode.
Cause
This issue occurs because Windows 2000 does not query the printer when bidirectional support is enabled. Microsoft Windows NT 4.0, and Windows XP poll the printer every few minutes when bidirectional support is enabled.
Resolution
To enable the printer to enter Sleep mode in Windows NT 4.0 or Windows XP, disable bidirectional support:
For Windows XP
Click Start, click Control Panel, click Printers and Other Hardware, and then click Printers and Faxes.
Right-click the Printer icon and click Properties.
Click the Ports tab, and then click to clear the Enable bidirectional Support check box.
Click OK.
For Windows NT 4.0
Click Start, point to Settings, and then click Printers.
Right-click the Printer icon, and then click Properties.
Click the Ports tab, click to clear the Enable bidirectional Support check box, and then click OK.
Status
This behavior is by design.
Suppose you can try it heh