The dot-matrix print head is a metal block with a number of holes occupied by metal pins which can be extended rapidly. This rests on a carriage which can move back and forth across the page. Between the print head and the paper is an inked ribbon. As the head moves across the page, the pins "fire" in a pattern dictated by the computer. When the pins fire, they force the ribbon onto the paper forming an image. Once one line is complete, another motor advances the paper so that another line may be drawn.
The print head block may be flat or curved. A curved block allows the pins to rest closer to the ribbon and paper. This minimizes the risk of damage and results in a quicker, more controlled strike.
