Most lasers use cartridge technology based on an organic photoconductive (OPC) drum, coated in light-sensitive material. During the lifetime of the printer, the drum needs to be periodically replaced as its surface wears out and print quality deteriorates. The cartridge is the other big consumable item in a laser printer. Its lifetime depending on the quantity of toner it contains. When the toner runs out, the cartridge is replaced. Sometimes the toner cartridge and the OPC drum are housed separately, but in the worst case, the drum is located inside the cartridge. This means that when the toner runs out, the whole drum containing the OPC cartridge needs to be replaced, which adds considerably to the running costs of the printer and produces large amounts of waste.
The situation is even worse with a colour laser – which can actually have up to nine separate consumables items (four colour toners, an OPC belt or drum, a developer unit, a fuser unit, fuser oil and a waste toner bottle). Many of these must be fitted when the printer is set up, and all expire after varying pages counts, depending on the manufacturer and usage. This high component count is a major reason for the cost and general lack of usability and manageability of colour lasers, and its reduction is a major focus for laser printer manufacturers.
Some have tried to improve this situation by making drums more durable and eliminating all consumables except for toner. Kyocera, for instance, was the first manufacturer to produce a cartridge-free printer which uses an amorphous silicon drum. The drum uses a robust coating which lasts for the lifetime of the printer, so the only item requiring regular replacement is the toner and even this comes in a package made from a non-toxic plastic, designed to be incinerated without releasing harmful gases.