All laser printers require consumables (supplies) from time to time. The replacement interval for a specific consumable depends on the brand of laser printer, the type of consumable, and the usage of the printer. On personal and office printers the consumables can be very expensive in proportion to the purchase cost of the printer, users who perform a lot of printing may spend as much in a year on consumables as the original cost of the printer. When choosing a printer it is therefore very important to consider the type of consumables it requires, the frequency of replacement required, and the cost of each consumable. The other major consideration when considering consumables is ease of use, some printers require several different consumables, which may be difficult to install into the printer, others provide all the consumables in one cartridge, which is easy and quick to replace.
All laser printers require toner (the "ink" in a laser printer) on a regular basis. The frequency of toner replacement depends on how much the printer is used, and how much toner is on each printed page. The need for other consumables, including developer, photoreceptors, fuser cleaning pads, fuser oil and ozone filters depends on the design of the printer. When purchasing a personal, office or workgroup laser printer the user should understand that the manufacturer is probably not making any significant profit on the printer, most of the profit is in the consumables which are sold to the user over the following years.
Toner is the "ink" within the laser printing process, the black or coloured substance which is applied to the page. Each page requires toner, the amount of toner depends on the area coverage of the image. Most typical pages of text have 4 - 5% of the paper covered with toner. The life of toner is normally quoted against a percentage coverage, so a manufacturer may claim that the toner will print X pages at Y% coverage. The higher the value of Y, the lower X will be.
Toner is supplied in four ways, depending on the design of the printer, either in a bottle, or in a toner cartridge, or in a combined toner/developer unit, or in a print cartridge (combined toner, developer and photoreceptor unit). The most economical of these is a toner bottle, which is normally only found on large printers. Toner is actually poured from the bottle into the toner hopper in the printer, the toner is such a fine powder that it pours like a liquid.
The next cheapest is the toner cartridge, which is simply a container designed to allow loading of toner into the printer without having to pour from a bottle (toner is very messy when it spills). Toner cartridges are found on all sizes of printer.
Toner/developer cartridges comprise the toner, toner hopper, developer and developer roller in one unit. Printers which use toner/developer cartridges are more expensive to use than printers which allow the use of just toner, as the developer in a printer normally lasts for many tens of thousands of pages, and so is discarded unnecessarily when the toner is replaced. Toner/developer cartridges are normally found on office and workgroup printers
Print cartridges contain all the consumables required for a printer, including toner, developer and photoreceptor. These are by far the easiest to use, as there is only one item in the printer which requires regular replacement, however they are also the most expensive. The photoreceptor and developer will normally last much longer than the toner supplied in the print cartridge, so they are replaced unnecessarily when the toner runs out. If the toner is used quickly by a user printing high-density pages, the rest of the print cartridge may have several thousand pages of life remaining, but the whole unit has to be replaced. Also, if a part of the print cartridge fails (the photoreceptor gets scratched or some similar problem), the whole print cartridge must be replaced. Print cartridges are normally found in personal and office printers, although a few workgroup printers also use them.
Developer is the substance which carries the toner from the toner hopper to the photoreceptor. Developer is not consumed, but becomes "fatigued", it loses its effectiveness. Developer will normally last for tens of thousands of pages, and so does not need replacing very often. On printers which do not use toner/developer cartridges or print cartridges the replacement of developer is normally a service operation performed by a maintenance engineer, but on non-production printers this is a very infrequent operation. Where a printer uses a combined toner/developer cartridge or a print cartridge, the developer is replaced as part of the cartridge. As the cartridge must be replaced when the toner runs out, the developer is normally replaced prematurely.
The photoreceptor is the drum or belt which receives an image written by the laser and transfers the toner from the developer to the paper. Photoreceptors gradually suffer from fatigue, the rate of deterioration depends on the type of coating used on the photoreceptor. Some types of photoreceptors will only last for around 10,000 pages, others may survive for several hundred thousand pages, or even millions of pages on production printers.
Most smaller printers have photoreceptors which require relatively frequent replacement (between 10,000 and 20,000 pages), in which case the photoreceptor may be replaced separately, or as part of a print cartridge. If the photoreceptor is part of a print cartridge it is normally replaced prematurely, when the toner runs out. The surface of a photoreceptor is often delicate and may scratch easily, in which case the photoreceptor must be replaced, as the scratch will show on the printed pages. Some printers, primarily production printers, have photoreceptors which last a very long time. Long-life photoreceptors have also been used by a few office and workgroup printer manufacturers, to make printers in which the photoreceptor never needs replacing because the rest of the printer mechanism is worn out before the photoreceptor.
The majority of laser printers use fuser oil, a special temperature resistant oil which is applied to the fuser rollers to prevent toner sticking to them. On production printers and large workgroup printers this is supplied separately, and must be poured into a small tank in the printer. Smaller printers normally incorporate the fuser oil into the fuser cleaning pad.
The fuser cleaning pad, often called a fuser wick, is a felt pad which lies against the fuser roller and removes any toner and dirt from it (a little toner is sometimes transferred from the paper to the fuser). The fuser cleaning pad becomes encrusted with toner and must be periodically replaced. On most small laser printers the fuser cleaning pad is also impregnated with fuser oil. The fuser cleaning pad is normally supplied with each toner cartridge or print cartridge.
All laser printers which use corotrons produce an amount of ozone (printers using charged rollers produce a negligible amount of ozone). Ozone is a corrosive gas which is dangerous in large quantities, and has an unpleasant smell. To remove the ozone produced by the corotrons, many printers have an ozone filter. This may be a small carbon mesh which is installed by the fan in the printer, or it may be built-in to the print cartridge or toner cartridge. The ozone filter has no effect on the operation of the printer, but is necessary to remove the ozone and prevent the printer causing an unpleasant smell. As ozone is dangerous in large quantities there are regulations in most countries which require ozone emissions to be below a stipulated level. The ozone filter is progressively contaminated by the ozone in the printer, and requires regular replacement.
A printer is a mechanical device, like all mechanical devices it will wear out, and most printers are built to provide a specific life under specified usage conditions. Therefore in considering the running costs of a printer it is necessary to consider the printer as a consumable. This approach to printer design may seem somewhat cynical on the part of the manufacturers, but in reality most products are engineered to survive beyond the point where the user wants to upgrade to a new model because new features have become available. Most personal printers are built to last for around 100,000 - 150,000 pages, although some of the very cheap personal printers are only expected to survive 30,000 pages (5 - 6 years at 100 pages per week). Office printers are typically expected to last around 300,000 - 500,000 pages. Workgroup printers vary enormously in their longevity, the smallest workgroup printers will probably only last 500,000 pages, the heavy duty models will, with regular maintenance, survive for many millions of pages. Production printers are generally designed to last as long as possible, the demands placed on production printers by different users vary enormously, and a significant portion of the cost of a production printer is in heavy-duty mechanical engineering. It is not uncommon for large production printers to be run almost continuously and produce over half a million prints a week, so with regular maintenance some production printers are likely to exceed 300 million prints before replacement.
The print cartridge used by some manufacturers is, as stated earlier, usually replaced before the photoreceptor and developer have finished their useful life. To exploit this, and reuse the mechanical elements in a print cartridge, some suppliers recycle print cartridges and refill them with toner. The degree of recycling varies considerably. There are many small companies who simply test the print cartridge and refill it with toner, others, including some printer manufacturers, strip and rebuild the print cartridge and provide a warranty for it.
Refilled cartridges are generally best avoided, unless the price is so advantageous that it mitigates for the risk of poor print quality sometimes asociated with refills. While most refillers do their best to test for good quality, the photoreceptor surface on a refilled cartridge may not be as good as a new cartridge, and the mechanical elements (gearwheels, drive belts etc.) may be unusually worn, leading to premature failure.
Print cartridges which have been stripped and rebuilt can usually be expected to perform satisfactorily, normally as well as a new cartridge. As the labour cost of disassembling, cleaning, checking and rebuilding a cartridge is similar to the cost of making a new cartridge, the price of rebuilt cartridges is normally only a little below that of new cartridges, but the user has the satisfaction of knowing that the materials used to construct the cartridge have not been wasted prematurely.