Brother rates the MFC-9640CDN at 24ppm in both black and colour print, which is a good speed for a mid-range office machine. In our tests, it reached 14.3ppm on the five-page test print, but this climbed to 21.1ppm on the 20-page document - not a long way off the spec sheet figure.
Interestingly, this is a full 2ppm faster than the Brother MFC-9645CDN, which is rated at the same speed. It’s not a consistent improvement, though, as the MFC-9640CDN was slower on the five-page document.
This printer handles duplex print as standard and completed the same 20-page document as a 10-page double-sided test, giving a speed of 13.0 sides per minute. This is again a good throughput for its class of printer, and is very similar to the more expensive Brother machine. The latter beat it on both the flatbed and ADF copies, though.
A single sheet colour copy took 14s, while the five-page black text copy took only twice as long, at 28s. Further good results came from our 15 x 10cm photo and full A4 photo tests, scoring 13s and 31s respectively.
Print quality is what you’d expect from a leading laser printer manufacturer. Black text is sharp and precise and toner saver mode is fine for everyday documents. Colour graphics are bright, though a bit dark by default, so black text over colour can be a bit hard to read. There’s a small amount of mis-registration and photos suffer from being too dark, too. You may need to adjust images before printing, to compensate.
Toner cartridges are available in two different yields and there’s the drum, transfer belt and waste toner bottle to consider, too. Even so, we calculate the overall running cost to be 2.9p for an ISO black page and 11.8p for ISO colour, both including 0.7p for paper. These costs are reasonable, even in a workgroup printer, where page costs are lower than with smaller machines.
The Brother MFC-9640CDN is a good, general-purpose, colour laser multi-function. All the main attributes are present, including a good performance, clean text and fair colours. Page costs are economical and at discount rates, the asking price for the printer itself is also reasonable.