Ink cartridge

Two cartridges (one with black ink, one with colored inks) installed in an inkjet printer

An ink cartridge or inkjet cartridge is a replaceable component of an inkjet printer that contains the ink (and sometimes the print head itself) that is spread on paper during printing.

Each ink cartridge contains one or more partitioned ink reservoirs; certain manufacturers also add electronic contacts and a chip that communicates with the printer.

[ Thermal

Most consumer inkjet printers, such as those made by Canon, HP, and Lexmark (but not Epson) use a thermal inkjet; inside each partition of the ink reservoir is a heating element with a tiny metal plate or resistor. In response to a signal given by the printer, a tiny current flows through the metal or resistor making it warm, and the ink immediately surrounding the heated plate is vaporized into a tiny air bubble inside the nozzle. As a consequence, the total volume of the ink exceeds that of the nozzle. An ink droplet is forced out of the cartridge nozzle onto the paper. This process takes a matter of milliseconds.

The printing depends on the smooth flow of ink, which can be hindered if the ink begins to dry at the print head, as can happen when an ink level becomes low. Dried ink can be cleaned from a cartridge print head by gentle rubbing with isopropyl alcohol on a swab or folded paper towel.

The ink also acts as a coolant to protect the metal-plate heating elements − when the ink supply is depleted, and printing is attempted, the heating elements in thermal cartridges often burn out, permanently damaging the print head. When the ink first begins to run low, the cartridge should be refilled or replaced, to avoid overheating damage to the print head.

Piezoelectric

All Epson printers use a piezoelectric crystal in each nozzle instead of a heating element. When current is applied, the crystal changes shape or size, forcing a droplet of ink from the nozzle. This allows use of inks which react badly when heated, and can produce a smaller ink drop in some situations than thermal inkjet schemes.

Variants

• Typically, two separate cartridges are inserted into a printer: one containing black ink and one with each of the three primary colors. Alternatively, each primary color may have a dedicated cartridge.
• Some cartridges contain ink specially formulated for printing photographs.
• All printer suppliers produce their own type of ink cartridges. Cartridges for different printers may be incompatible — either physically or electrically.
• Since replacement cartridges from the original manufacturer of the printer are often expensive, several vendors produce "compatible" cartridges as less expensive alternatives. These cartridges sometimes have more ink than the original OEM-branded ink cartridges and may produce the same, better, or inferior quality, depending on a variety of factors, including the vendor's ability to duplicate the ink formulation in all respects. Although compatible cartridges "have been designed to be interchangeable with an OEM cartridge,"they have been known to cause serious damage to some makes and models. This can be especially problematic when the use of these cartridges leaves the printer void of warranty - a policy which varies from country to country.
• Some cartridges have incorporated the printer's head (examples include HP, Dell, and Lexmark). The precision parts required generally make the cartridges more expensive, but the printers are cheaper since they don't include the precision print head. Other cartridges don't include the print head and so can cost less, though the printers tend to be somewhat more expensive (Epson is an example).

[ Pricing

Ink cartridges are typically expensive, sometimes a substantial fraction of the cost of the printer. To save money, many people use compatible ink cartridges from a vendor other than the printer manufacturer. The high cost of cartridges has also provided an incentive for counterfeiters to supply cartridges falsely claiming to be made by the original manufacturer. Another alternative involves modifications of an original cartridge allowing use of continuous ink systems with external ink tanks. Others use aftermarket inks, refilling their own ink cartridges using a kit that includes bulk ink.

Some printer manufacturers set up their cartridges to interact with the printer, preventing operation when the ink level is low, or when the cartridge has been refilledOne researcher with the magazine Which? over-rode such an interlocked system and found that in one case he could print up to 38% more good quality pages, after the chip stated that the cartridge was empty.In the United Kingdom, in 2003, the cost of ink has been the subject of an Office of Fair Trading investigation, as Which? magazine has accused manufacturers of a lack of transparency about the price of ink and called for an industry standard for measuring ink cartridge performance.Which? stated that color HP cartridges cost over seven times more per milliliter than 1985 Dom Perignon.

Consumers are often surprised at the price of replacing their printer cartridges, especially when compared with that of purchasing a brand new printer.Sometimes it can even be cheaper to buy a brand new printer every time you run out of the free ink that is initially supplied. The major printer manufacturers − Hewlett Packard, Lexmark, Dell, Canon, Epson and Brother − use a "razor and blades" business model, often breaking even or losing money selling printers while expecting to make a profit by selling cartridges over the life of the printer. Since much of the printer manufacturers' profits are from ink and toner cartridge sales, some of these companies have taken various actions against aftermarket cartridges.