Canon rates the PIXMA MX420 at 8.7ppm in black and 5.0ppm in colour. Under test, we saw a speed of 5.6ppm for our basic black text document, rising to 6.9ppm on the 20-page variant. This is reasonably close to the stated figure and is quite quick for this class of printer. The five-page text and colour graphics test gave 2.3ppm, less than half the rated speed.
A single page colour copy took 35s and the five-page black text copy from the ADF took 1:10, both respectable times. Finally,15 x 10cm photo prints took between 53s and 1:08, depending on source.
Print quality from Canon machines is usually very good and the PIXMA MX420 lives up to this reputation. Black text is clean and sharp, with little of the fuzziness or spatter seen on some other mid-range all-in-ones. Colour print, too, is smooth and without banding, though the colours are not quite as vibrant as some others on plain paper.
Photo prints are excellent, with no signs of visible fill patterns, good colour rendition and plenty of detail in light and dark areas of each image. Some may feel there's a slight emphasis to the red part of the spectrum, while others will just think it prints warm.
There are two yield levels for the black cartridge and just one for the tri-colour and, at the best prices we could find, costs come out at 4.3p for an ISO black page and 9.1p for colour. These figures are towards the top end of the cost spectrum and the black print in particular looks pricey.
Canon's PIXMA MX420 is a perfectly serviceable, mid-range SOHO all-in-one. While it lacks some of the refinements of its bigger siblings, particularly their twin paper trays, it offers excellent print, reasonably quickly and handle photos just as well as plain paper documents. It's quite pricey to run, though, which brings the machine’s value down a bit.