Virtually all consumer reports on the subject of colour printing affirm that for high-volume printing, a colour laser printer is more economical to own than an ink-jet printer, owing primarily to the cost of consumables when evaluated on a per-page basis. But even knowing that information, most people look at the retail price difference between them, and find the expense hard to justify. Buying a laser printer can cost 15 times what one would pay for an ink-jet printer, and since many feel that their own at-home printing needs are not that high, if they print relatively infrequently, shouldn't an ink-jet be more practical for a person on a budget?
If all other things were equal, probably. But they aren't equal. The volumes of pages that are managed by each type of cartridge are vastly different. An ink-jet cartridge is good for perhaps a hundred pages or so, whereas toner cartridges are good for a thousand pages or more. Toner cartridges typically cost about 5 to 6 times what an ink-jet cartridge does, but the fact that toner is good for at least 10 times as many pages affirms that laser printing is certainly economical for high volume printing. But low to moderate printing volumes, which most home users would probably say they fit, wouldn't it take a very long time for the costs of cartridges to finally outweigh the enormous initial investment in a laser printer?
Well, consider that ink-jet printer ink is wet, and it will dry out eventually. This means that it can and will dry on the printer heads, clogging them. This phenomenon is familiar to anyone who has ever used a ball-point pen that is still obviously very full of ink but the ink comes out very faded or stops completely while you are writing because part of the ink inside the pen has dried out. Pretty much the same thing happens with all ink-jet printers. Most ink-jet printers come with a utility for cleaning the heads, but using this utility typically uses very large amounts of ink, causing the cartridges to be depleted that much faster, and quite frequently the results are less than stellar, requiring several re-cleaning attempts before the image quality is acceptable. Ultimately, there is no practical way to keep ink from drying on the ink heads other than either diligently cleaning them manually (which is a tedious process that may or may not produce results) or else fairly heavy use of that particular cartridge. Of course, if you are so constantly using ink, then in all probability, you are pushing into high volume printing, where it is virtually unanimously agreed upon that laser printing is more economical anyway.
Further, because ink-jet cartridges are not air-tight, ink can dry up while inside the cartridge... and that dried up ink still takes up space inside the cartridge. The life cycle of a ink-jet cartridge is reduced even further by this phenomenon, and in general, every ink-jet ink cartridge needs to be replaced at least a couple of times a year. In all fairness to ink-jets, however, proper* storage of ink-jet cartridges in sealed plastic bags whenever the printer is not in use can drastically extend the life of the cartridges. Ink-jet printer manufacturers often even recommend that consumers store their cartridges this way if the printer will be off for more than a few days, anyway. But even the most diligent and correct storage of unused cartridges cannot push an opened cartridge past about a year or so, and that's even if one doesn't already use up all the ink in the cartridge long before then. Even completely unopened cartridges cannot be used past approximately 2 years since their original manufacture date.
Toner, on the other hand, is dry. Toner cartridges can be used for many years with no perceivable loss of quality as long as there is toner in the cartridge left to print. So toner cartridges that are relatively unused have to be replaced that much less frequently. The impact of wet ink versus dry toner cannot possibly be overstated. Even for very low volume printing, the break-even point at which time running a laser printer would be more economical than using an ink-jet is far sooner than most people realize simply owing to otherwise premature replacing of ink-jet cartridges with dried-up ink in them. Even printing as little as an average of two colour pages a day, one will have spent more money in just one year on replacement cartridges for an ink-jet printer than it would have cost to initially buy an inexpensive colour laser printer, and in that same amount of time, the original toner cartridges purchased with the printer would still have considerable life left in them before they would need replacing,
Now of course, there are such things as dry ink-jet printers, which use solid ink blocks, and use heat to melt the ink before applying it to the page. These printers can be more economical over the long run than either ink-jet or laser printers, but they are much more expensive than conventional ink-jet printers and even some colour laser printers, and more importantly, the ink can melt and run after it is printed if it is left in a warm place, similar to how ink-jet ink will run if the page it is on gets damp.** Toner from a laser printer does not run, regardless of the environment the page is in.
There is one venue of printing that ink-jet printers absolutely excel in, and that is in the quality of printing colour photographs. Ink-jet printers are far and away better than virtually all home colour laser printers in this regard. There are colour lasers that do this job very professionally too, however... but they are prohibitively expensive for the home consumer, costing sometimes tens of thousands of dollars and although they may be practical for a business that does very large volumes of photo quality printing daily, they are not at all likely to be practical around the home. Most home colour laser printers do an adequate job of printing photographs, however, and although they are certainly not at the same level as ink-jet printers in this department, most are still very capable of producing very attractive photographs. As a final point, it is worth noting that ink-jet printers typically consume between 50 cents to a dollar worth of ink printing a whole page of colour photos (not counting ink that dries up inside the cartridge), where laser printers typically use about 10 cents worth of toner. One must weigh whether or not the costs per page issue is actually worth the extra quality for themselves before making a final decision.
**Addendum: June 6, 2008:
I've had the opportunity since I originally wrote this article to use an inkjet printer for some time now that utilizes so-called newer ink technology claiming to be more economical on a per-page basis than a laser printer and also claiming to not run on the page if it should get damp. An analysis of my experience with this type of printer follows:
The latter claim is truer than it used to be... that is, newer ink does not run *AS MUCH* when it gets damp as other inks do. This is true for HP's Vivera line of inks, at least. The difference is substantial here, so kudos to HP. If future improvement in this area is only half again as good as it has been, the next generation of inks may not run perceptibly at all.
The former claim, however... although there is a substantial improvement in this area over older printers, is still nothing but a pipe dream. In my experience, HP's Vivera line of inks can print roughly twice as much material as one could with other printers for approximately the same cost of ink, but this is still between half to one-quarter the amount of material that one can print for the same costs in toner supplies. I might speculate that the major problem that is driving costs up in this area is still ink drying up in the cartridges before it has a chance to be consumed.
*Proper storage of an ink-jet cartridge includes putting a piece of cellophane or scotch tape over the hole so that ink does not leak out, and putting it in zip-lock or other sealed plastic bag with as much of the air as possible removed and then stored in a cool, dry place.