The HP Officejet Pro K850 is an expensive, single-function printer that fills a small niche in professional settings. This $400 color inkjet can handle medium-format media, but it uses basic, four-color printing instead of six-color for better range of color. Its print quality and speed are good enough for small-scale production of marketing collateral, but serious graphic designers who want slick brochures will be disappointed. If you need a network-ready printer with a duplexer, the K850dn offers both for an additional $100. Offices that require more standard office printing should look for a laser printer that can handle high volumes of prints quickly. Small offices that don't need medium-format media handling should check out the less expensive HP Officejet Pro K5400.
The HP Officejet Pro K850 is an enormous inkjet printer because it can handle medium-format media, up to 13 inches wide versus 8.5 inches on a typical, consumer-level printer. The black-and-silver printer measures 24 inches wide, 17 inches deep, and 8 inches tall, and weighs 27.1 pounds. The duplexer on the K850dn adds an inch or two to the depth when attached to the rear of the printer. The K850's control panel is simple: power, cancel, and paper feed buttons and a set of icons that light up to indicate various problems, including a paper jam, an empty input tray, and low ink levels.
The printer's output tray sits atop the input cassette and tilts up so you can access the paper. The output tray features paper guides and two extension leaves that help corral longer prints. The input cassette also offers adjustable paper guides that let you neatly insert media ranging from 3x5 inches to 13x19 inches.
The four ink tanks reside separately from the print heads and are hidden behind a spring-release panel on the top of the printer. The K850 uses a pigment-based black (for better black text prints over dye-based black) and dye-based cyan, magenta, and yellow inks. Many photo-oriented printers--even consumer-level ones--offer six-ink printing (or more) for a better range of colors over four-color printing, which means the K850 isn't the ideal printer if you're working mainly with high-end graphics. It ships with the standard-yield cartridges, which cost $25 apiece, but you can replace those with high-yield cartridges: the black costs $34, while the color cartridges cost $38 each. Using the high-yield cartridges, HP estimates a black page can cost as low as 2.2 cents and a color page can cost as low as 8.4 cents--both numbers are low for an inkjet printer. Its monthly duty cycle is 6,250 pages, so if your office has high-volume printing needs, this isn't the printer for you.
As a single-purpose office inkjet, the features are not surprisingly spartan. The Officejet Pro K850 can be connected via USB 2.0 or parallel port, but HP also sells an optional print server if you want to network the printer. (If you want both a duplexer and a network connection option, the K850dn offers both.) It ships with a 256MHz processor and 32MB of memory, standard for an inkjet printer. The print driver lets you make N-up prints, poster prints, and assists with manual duplexing if you have not purchased the duplex model.
It's difficult for us to make performance comparisons to the Officejet Pro K850 because we haven't reviewed similarly priced single-function inkjets. Most inkjets that fall into this price range are either multifunctions or professional graphics-oriented inkjets. The Pro K850, with its four-color printing and lack of any photo-oriented features such as a PictBridge port, is squarely an office inkjet printer.