Samsung claims a print speed of 16ppm for the ML-1640 and, for once, we don't disagree. Our five-page text print took 30 seconds to complete, so a print speed of 10ppm, but when we ran our 20-page job, it completed in 1:24, which is 14.3ppm. As you extend the length of a print job, so the processing time becomes a smaller and smaller part and we could see the machine reaching 16ppm on a job of 100 pages or so.
The quality of pages produced by this printer is very good for a mono laser at well under £100. Text print is precise and clean and there's little sign of toner spatter making the edges of characters fuzzy.
Greyscale graphics are also well reproduced, with enough difference between shades to differentiate between colours. There's some very slight banding, but you have to look quite closely to see it and black text over greyscale fills shows up well.
Our test photo was also reasonably well reproduced, though the enhanced 600 x 1200dpi resolution leaves the image looking a little dotty. Even so, there's a surprising amount of detail in the shadows and we would be happy to use photos in external as well as internal documentation.
We noticed a couple of idiosyncrasies when running our tests. For a start, pages feeding to the top paper tray would occasionally catch the trailing edge of the preceding sheet, pushing it out of the tray at an angle. This may have been linked to the slight paper mist we could see as pages were fed out. Because the fuser in this machine sits so close to the output slot, it could be part of the water content of the paper vaporising into these small wisps.
Having said that, we were using the same paper, from resealable packs, stored in our lab at office temperatures, so we wouldn't expect the moisture content of the paper to be particularly high.
The single running cost is the combined drum and toner cartridge and with this priced around £42 online, we come up with a cost per page of 4.02p, including paper and VAT, which is around 25 percent higher than from the Canon i-SENSYS LBP-3100. While all companies have to recoup some of the low sale price of entry-level laser printers in their consumables costs, four pence per sheet is high for a mono page.
This is a neat, functional mono laser printer, which is easy to use and produces good quality text and graphics prints at speed. Its comparatively expensive to run, though, and we would like to see some dust protection for paper sitting in the feed tray. You need to compare it with competitors, such as the highlighted Canon machine, before making a final choice.