HP 305A

A toner cartridge, also called laser toner, is the consumable component of a laser printer. Toner cartridges contain toner powder, a fine, dry mixture of plastic particles, carbon, and black or other coloring agents that make the actual image on the paper.

The toner is transferred to paper via an electrostatically charged drum unit, and fused onto the paper by heated rollers during the printing process.

A cartridge (also called a round or a shell) is a type of ammunition packaging a bullet or shot, a propellant substance (usually either smokeless powder or black powder) and a primer within a metallic, paper, or plastic case that is precisely made to fit within the firing chamber of a firearm. The primer is a small charge of an impact-sensitive or electric-sensitive chemical mixture that can be located at the center of the case head (centerfire ammunition).