You attach the printer to the Internet through a router, and it receives and prints out a randomized e-mail address. You can then configure the address through the HP ePrint server to receive mail from anyone, or only from a select list of e-mail address. (I left mine open, and no spam has shown up yet.)
You send your documents as attachments to the printer's e-mail address. If there is text in the e-mail message itself, it will print on a separate page. The e-mail header is not printed. You are limited to five megabytes and 10 attachments per message, and file types are limited to Microsoft Word, PowerPoint, Outlook, and Excel, plus txt, PDF, and 100 dpi or better bmp, jpg, png, gif, and tiff images. (With the latest Microsoft Office you can just output your material to a PDF file, and send that file to the printer.)
In printing file attachments the results seemed faithful to the original. I saw no discrepancies. Raw e-mail text could have odd letter spacing, however.
With a broadband connection, printing can start anywhere from 15 to 90 seconds after sending the e-mail. There seemed to be no obvious connection between file size and the time it took to begin printing.
Or so I discovered after getting it to work.
For several days I couldn't. I would send the e-mail, nothing would print out, and several minutes later I would get an e-mail message indicating that transmission had failed, always saying "550 5.7.1 Command rejected."
I called HP customer service, which is free under their one-year warranty. The first time the technician surmised that the ePrint server was down for maintenance. After the situation persisted I called again. There was no progress but the technician looked into the matter and called back later, saying his "third level" technician suggested going to my router vendor and getting instructions for setting a DMZ for the printer. (This sets up a connection to the printer that is free of security complications.)
While contemplating his suggestion I browsed the user forum attached to HP's ePrint Web site, and came across people having the identical problem. One said the 550 error message concerned Microsoft e-mail and could be avoided by using Hotmail. I was using Microsoft Outlook 2007 for e-mail. (Yes, it's listed as having been tested with ePrint.)
I switched over to my free Hotmail account. Printing from there proceeded flawlessly. Obviously, the absence of a DMZ was not the problem.
Equally obviously, HP's reach exceeds its grasp. The ePrint facility could be a valuable tool for road warriors and decentralized offices, but first it has to work reliably, without resorting to stopgap measures.
Meanwhile, the real potential for ePrint is for it to work with iPhones, Blackberries, and other smartphones. After all, if you can print from your handheld that means there is one less reason to lug around a laptop and I suspect a lot of people, especially lady professionals, would love to be free of the things.
The problem is that ePrint is supposed to be as compatible with the Blackberry and Apple mail clients as it is with Outlook. That's not a good feeling.