Which of the following is NOT a type of printer?

The choice of "Scanner printer" as the option that is NOT a type of printer is based on the fact that a scanner is primarily a device used for digitizing physical documents and images, rather than producing physical printed outputs. While there are multifunction devices that include scanning capabilities along with printing, the term "scanner printer" itself does not accurately represent a distinct type of printer like the other options do.

Dot-matrix, LED, and laser jet printers are all established categories of printers that utilize different technologies to produce printed material. Dot-matrix printers use a series of pins to strike an ink ribbon and transfer ink onto paper. LED printers use a light-emitting diode array to create an image on a drum that in turn applies toner to paper. Laser jet printers use a laser beam to produce an image on a drum, which is then coated with toner and fused onto paper.

Understanding this distinction emphasizes the specific functionalities of printers versus scanning devices, which is key in computer fundamentals for business practice. Each printer type mentioned produces printed material, while the "scanner printer" terminology lacks a standardized definition in the context of printers.