USB printer stops responding

A coworker has an HP Deskjet 2330 printer attached via USB. Every
couple of days it stops responding. No errors and it shows up in the
tray as 'printing'.

If he unplugs the USB cable at the PC and plugs it back in, it prints
immediately. (He gets the USB 'ding' when plugging it back in, but no
ding when unplugging it.) It does NOT work to unplug the USB at the
printer. Nor does it work to power cycle the printer. It's almost as
if something goes into a standby or sleep mode and can't recover,
though I don't see any settings for that. If this is indeed the
problem, I would call that a firmware issue. He has the latest
driver.

A Google search suggested maybe either 1) shared IRQ issue, or 2) a
power issue in that the printer is drawing too much juice.

#2 sounded plausible. He has the printer behind him with a 6' USB
cable plugged into the PC, then a USB hub (nonpowered), then another
6' USB cable. To test this theory, I swapped him cables as I had a
12' USB cable so I could reach my printer. If _I_ now start having
that problem . . .

Suggestions welcome.