Product Reviews

Over the past three years, inkjet printer technology has undergone dramatic changes. Ever since the introduction of the original Epson Stylus products - the 500, 600 and Photo printers - the inkjet market has seen a frenzy of launches and the big three manufacturers have traded blows in an intense battle to be first with the highest resolution, greatest number of colours and/or fastest speed. Epson has led the way for the most part, with Hewlett-Packard and Lexmark following close behind.

Of late, however, Lexmark appears to have been slowly slipping further behind. Its Z51 printer (reviewed issue 58, p162) would have fared extremely well in issue 56's inkjet Labs tests but didn't appear until two months later. Four months on from that we have the Z31, the Z51's lower-end cousin. In the meantime both HP, with its DeskJet 970Cxi (reviewed issue 61, p156 ), and Epson, with its forthcoming 660 and 760 printers, have begun to move on to the next generation of inkjets.

The Z31 retains the distinctive look of the Z51 with the same squat, curved and fairly featureless casing. Just two buttons and two LEDs adorn the top - power and paper-feed controls - while connections at the rear remain minimal. There's no USB port, as with many recent releases, just parallel and power connections. The main paper tray folds out neatly from the top, exposing a 100-sheet capacity paper bin and a single-sheet/envelope-feed slot, and a solid-feeling output tray extends at the front to occupy 293 x 461 x 520mm (H x W x D) of deskspace. Lift the printer's bonnet up and the twin-cartridge system presents itself for inspection.

Installation went as smoothly as it always does with Lexmark printers. It's not quite as slick as HP's new-fangled laser-automated head-alignment process, but once connected to a PC and plugged into the mains the process is straightforward enough and doesn't take too long.

So what's the difference between the Z31 and the Z51, apart from the price? Well, it's the same resolution, at 1,200 x 1,200dpi, but the Z31 claims a slower print speed at 8ppm for monochrome and 3.5ppm for colour prints. More crucial than this though, is the fact that it delivers ever-so-slightly larger ink

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drops from a different colour ink cartridge. Whereas the Z51, it's claimed, can shoot dots as small as seven picolitres in volume, the Z31 only produces 18-picolitre drops. Once we began to put the Z31 through its paces, the lower level of specification became apparent.

For starters, we couldn't get anywhere near the printer's claimed 8ppm maximum speed. Even using the Z31's Quick Print mode to print 25 pages of sparsely covered plain text pages only resulted in a print speed of 4.62ppm. The print quality generated by this mode isn't particularly presentable either, due to a disturbingly regular horizontal tearing effect. Pushing the print quality up to the printer's Standard mode (still at 600dpi) all but eliminates the problem and gives extremely crisp, dark text, but drops the printing output speed accordingly to a slow 2.4ppm. However, in this mode, the Z31 manages to produce text that's about the same, almost-laser, quality as the Z51.

Where the difference between the Z31 and the Z51 really becomes obvious is when carrying out more demanding tasks. In fact, in a side-by-side comparison it's actually possible to see the Z31's dot-size deficit with the naked eye. Our full A4 photographic test, which took the Z31 just over 10 minutes to complete on both coated and glossy paper, looks significantly more coarse and grainy than the same print produced by the Z51. It certainly doesn't come anywhere near our current A List resident, the Epson Stylus Photo 750, for smooth, blemish-free detail. The large dot size also becomes evident in smooth colour fades and light shading, where clear dithering patterns are visible.

As mentioned earlier, the Z31 doesn't employ the same colour cartridge as the Z51, but this doesn't seem to have an adverse effect on print costs. The printer comes as standard with one black and one three-colour cartridge, which cost £19.53 and £23.57 respectively to replace. According to Lexmark's claims, these prices mean that a page of text at five per cent coverage will cost around 3.3p, excluding paper, and for a colour page at five per cent coverage per colour you'll pay 11.8p. We'd say this is over the odds, especially when you consider a full-page colour photograph will use a lot more ink than just five per cent coverage per colour, but it's still only a little above average for the industry.

Overall, the Z31 isn't a bad little printer - the quality is certainly better than that produced by Lexmark's last mid-range offering, the Color Jetprinter 3200 (reviewed issue 56, p134). And although it doesn't live up to its speed claims, it isn't frustratingly slow. The trouble is that it isn't quite cheap enough. For just a tenner extra you can lay your hands on a Z51, which is capable of far better results and costs almost exactly the same to run.