open box and refurbished are usually different things.
open box is an item that is returned to retailer by customer for various reasons: didn't work with the rest of their setup, blemishes, some non critical component failure, got a better version as a christmas gift, what have you. The retailer generally tries to make sure all the parts are there and throws it back on the shelves with the disclaimer that the item may not be retail pristine, primarily so they don't lose too much of the money they already spent.
factory refurbs are items that failed or were doa and returned under warranty. The item gets sent back to the manufacturer who diagnoses the problem and fixes the easy ones. The item is re-packaged with all parts and sent out. (not sure if it goes back to the retailer who originally bought and returned the item) The item is discounted because it doesn't have the "new car smell" but is fully guaranteed to function properly.
I've bought printers and other electronics that were refurbs. the savings are nice and you know somebody has already made sure it works rather than some partially automated factory burn-in test. The only open box item I've ever bought was a digital camera at frys. All the parts were there, and i was able to handle it in person to make sure everything worked. (I think someone didn't like the color of the casing and returned it.)