The OKI C610dn ($789 list) adds an automatic duplexer to the OKI C610n ($649 list, 4 stars) color LED printer. The printers are otherwise identical, and in our tests, their speed and output quality were similar. The C610dn offers a good balance between features, performance, and output quality for small to mid-sized with fairly heavy-duty color printing needs. If you expect to print even occasionally on both sides of a sheet of paper (which can save large amounts of paper in printing rough drafts), it makes sense to get the C610dn, as it saves you money over buying the C610n and adding an optional duplexer after the fact.

As an LED-based printer, the C610dn uses light-emitting diodes (LEDs) in place of lasers as a light source; LED printers are considered laser class. The C610n, off-white with a brown top and a dark brown front panel, measures 13.4 by 21.5 by 17.1 inches (HWD) and weighs 57.3 pounds. It has a monochrome display for showing the menus; it also displays the levels for each color of toner.

The C610dn has a duty cycle of up to 75,000 pages per month. Its standard paper capacity consists of 400 sheets, split between a 300-sheet main tray and a 100-sheet manual multipurpose tray. You can add up to two optional 530-sheet paper trays ($230 list each) to boost capacity for a maximum of 1,460 sheets. The base model, the C610n, lacks an automatic duplexer but offers one as an option for $179, though you'll save $30 by buying the C610dn with its standard auto-duplexer. Another model, the C610dtn ($980 list) comes with the duplexer as well as an additional 530-sheet tray for a standard paper capacity of 930 pages, while the C610cdn ($890 list) eschews the extra tray but comes with the duplexer plus a 16GB SD memory card.

The C610dn offers USB and Ethernet connectivity; I tested it on an Ethernet network with its drivers loaded on a PC running Windows Vista.

Print Speed and Output Quality
I timed the OKI C610dn on the latest version of our business applications suite (using QualityLogic's hardware and software for timing), at an effective 6.7 pages per minute (ppm). The C610dn has a rated print speed of up to 34 ppm for monochrome and 32 ppm for color printing, about what we'd see if it were printing solely text pages. Our test suite consists of text pages, graphics pages, and pages of mixed content. It was a little slower than the OKI C610n, which I timed at 7.2 ppm on the same tests. The Editors' Choice Xerox Phaser 6280DN rated at 31 ppm for monochrome and 26 ppm for color output, was clocked at 4.5 ppm, and the Samsung CLP-670ND, rated at 25 ppm for both color and monochrome, tested at 5.7 ppm.

We don't usually test duplexing speeds, but we did in this case as the addition of the standard auto-duplexer is the only difference between the C610n and C610dn. It took about 40% more time to print out 10 pages as a 5-page, double-sided document than it did to print the same 10 pages in simplex (single-sided) mode, one page to a sheet. That's an acceptable speed for a duplexer.

Output quality was nearly identical to that of the C610n: Its graphics and photos were typical of color lasers, while text quality was a little below average for a laser printer. That still makes the text quality suitable for most business uses, except for those requiring small fonts such as demanding desktop publishing applications.

OKI promotes the output from the C530dn and its other recent LED printers as "HD Color Printing." Colors for both photos and graphics were rich and well saturated, although blacks were a bit muted and several photos and illustrations showed a very slight reddish tint. Despite generally vibrant colors, a host of flaws reduced the overall quality for both graphics and photos to being typical of color lasers.

Graphics were suitable for any normal business use up to and including PowerPoint handouts. Issues included dithering (graininess); uneven ink distribution; posterization (abrupt shifts in color where they should be gradual), trouble printing very thin lines, and mis-registration (misalignment between areas of different color).

With photos, issues included dithering, posterization, and aliasing (the tendency for straight lines to take on a jagged appearance), and mild banding (a pattern of streaks of discoloration). Depending on how picky you (and your clients) are, the quality may good enough for printing out a typical newsletter containing color photos.

If you have a need for printing two-sided documents (if only as a paper-saving measure), the $140 premium you'd pay for the C610dn's auto-duplexing over the C610n is worth the extra expense, and it's more economical than adding an optional auto-duplexer to the C610 after purchase. Output quality for the two OKIs is nearly identical, and their print speeds are similar as well. (The non-duplex version was a half page per minute faster, but we don't consider differences of less than 1 page per minute as significant.) The C610dn is faster than the Editors' Choice Xerox Phaser 6280dn, so it may be your printer of choice if speed is your prime consideration—but its output quality is no match for the 6280dn.

BENCHMARK TEST RESULTS
Check out the test scores for the OKI C610dn.

COMPARISON TABLE
Compare the OKI C610dn with several other laser printers side by side.

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