Pentax PocketJet 3

If you need a portable grayscale printer to carry on a business trip, the Pentax PocketJet 3 may fit your bill. But with its $349 price tag, you're paying a premium for portability, especially given that the PocketJet 3 prints at a mere 200dpi (the 300dpi Plus version costs an extra $100). If you just need to print tiny black-and-white receipts on the road, check out the pocket-size Brother mPrint MW-140BT. And if you prefer a larger portable printer that manages photos as well as letter-size text documents, scope out the Canon Pixma iP90 or the HP Deskjet 450wbt. Still, the unique Pentax PocketJet 3 meets a niche need if you prize portability and have to print letter-size documents.

We find this petite PocketJet, about the size of an elongated stapler, easier to carry around than a portable but boxy inkjet printer. The PocketJet 3 measures 10 inches wide by 2.25 inches deep and 1.25 inches thick and weighs about a pound--a fraction of the size and the heft of a portable inkjet alternative such as the Canon Pixma iP90. This Pentax printer can operate on AC power, a battery, or DC power from a car cigarette lighter. You can hook up the printer to PCs, Macs, and several handhelds via USB or infrared connections. The PocketJet 3 comes with an AC adapter and a battery specified to print 100 pages on one charge and to last 400 discharge cycles. A spare lithium-ion battery costs $39, and a car cigarette-lighter adapter runs $19. Pentax provides a cushioned case for the printer with a pocket to hold the supplied USB cable but not the power adapter.

The PocketJet 3 is a thermal printer, which means no thirsty ink tanks to refill, but you'll have to spring for pricey heat-sensitive paper--the kind you may remember from fax machines of yesteryear. Pentax sells a box of 100 letter-size sheets for $11; at 11 cents a page, that's still less than what many inkjet prints run. A box of six 100-foot rolls goes for $42 and offers the equivalent of 660 pages, or 6.4 cents each; a roll with perforations goes for $48. It was tricky to distinguish the smoother printable side from the back side, so we frequently fed the roll backwards into the printer, wasting already expensive paper. Thermal paper emits a faint chemical smell and can darken over time, obscuring the printed image--especially if exposed to sunlight. Pentax guarantees your prints to last for 7 to 10 years under normal office filing conditions, but you'll have to wait a decade to verify that claim.