There are two main kinds of cartridges: inkjet and xerographic toner. Both types
accomplish the same function, but in two very different ways. Xerographic toner printers use toner powder, whereas ink cartridges use liquid ink. Due to the differences in printing mediums, the mechanics of each cartridge are fundamentally different. These differences contribute to their varying cost and ability to be recycled.
Toner cartridges work by using three main parts: the toner hopper which holds the toner
powder, the developer unit which is an assortment of negatively charged magnetic beads, and a metal drum that the beads are attached to. The revolving drum coats the entire sheet of paper with a positive electric charge. Then a laser removes the positive charge in the places where the image is going to be printed, leaving behind a negatively charged electrostatic image. Since the toner contains compounds that carry a positive charge, namely iron oxide, the negatively charged beads pick up the toner from the hopper. As it is being rolled over the paper, the toner is attracted to the places where the laser created a negative image. Before the page is printed it out, it goes through a pair of heated rollers called a fuser which melts the toner onto the page (Harris, 2007).
This process allows for speed, economy, and efficiency—you are able to print more for the amount of toner purchased. Since toner is usually sold in larger quantities, however, its unit cost per cartridge is higher than that of ink. Inkjet cartridges are slightly more straightforward but the technology within the cartridge is equally as innovative as the toner cartridge. Within an inkjet printer, the ink is contained in an 26 airtight foil-lined compartment. As the cartridge deposits ink onto paper via small jets, the
airtight compartment volume decreases because of a vacuum effect. Within the cartridge there is a silicon chip with microscopic jets – small etchings in the chip that act as hydraulic jets – which are connected to a metal plate underneath the ink compartment. When electricity passes through the metal plate it superheats the silicon chip and a small droplet of vaporized ink is released through these small etchings.
A basic black inkjet cartridge for a small personal printer with 600 dots per inch (dpi) contains a matrix of about 300 jets and up to 14 jets can be fired in 22 different phases (Wandel, 2003). This process can create dots approximately 55 microns wide, smaller than a human hair. More jets can create a dpi up to 1440×720, surpassing the resolution of most toner cartridges. On a price per print basis, inkjet cartridges print higher cost prints that that of toner. The cost of an inkjet cartridge however, is less than that of toner
cartridges (Tyson, 2001).