Photonal, even when you scan using Preview or Image Capture, you are still using the driver from HP, it's just that the HP driver used here being a module (in current case, ICA module).
http://support.apple.com/kb/HT3669 shows that there are scan driver for your device. The reason you don't see the device in the application may vary:
1. If you connect the device to the USB port of an Airport base station, you need to change that since it is a configuration current ImageCapture doesn't support. Connect the device directly to a USB port on your computer or to an ethernet port of your Airport base station.
2. If direct USB connection still doesn't work, one possibility is that you still have remnant of older HP scan application which prevented ImageCapture from connecting to the device. Try to uninstall the drivers (everything, including the value-add applications), then delete the printer queue in Print & Fax preferences, then reboot the computer. After that you should get a dialog asking you to install the driver, say "yes".