Dot Matrix Printer Overview

Jun 7, 2025

Overview

This lecture explains how dot matrix printers work, their key components, typical uses, advantages, and limitations compared to other printing technologies.

How Dot Matrix Printers Work

  • Dot matrix printers use a matrix of small pins to strike an ink ribbon, creating dots on paper.
  • The print head moves back and forth across the page while the paper advances line by line.
  • Each character or image is formed by patterns of tiny dots made by the pins.
  • Print heads can become warm, so they often have heat sinks attached.

Components and Operation

  • The ribbon is a continuous cartridge spanning the width of the paper, easy to replace.
  • Each printer model may require a specific size ribbon.
  • Printer uses tractor feed with holes, called tractor paper, to guide and align the page.
  • Tractor feed holes must be properly aligned to avoid paper jams.

Types of Paper Used

  • Tractor paper is either continuous or perforated for standard page sizes.
  • The perforated edges with holes can be torn off after printing for a cleaner look.
  • Green bar paper is a common type used for programming output and source code.

Special Printing Features

  • Dot matrix printers can create multi-part forms—multiple copies in a single print using special paper.
  • Multi-part forms may use carbon or microencapsulated ink with clay to transfer writing to duplicate sheets.
  • Handling multi-part forms can cause skin irritation for some users.

Advantages and Disadvantages

  • Dot matrix printers are ideal for multi-copy and carbon forms but are noisy and produce low-resolution output.
  • They have a low cost per page, making them suitable for high-volume print jobs.
  • Nowadays, they are mostly used in niche or legacy environments due to noise and lower print quality.

Key Terms & Definitions

  • Dot matrix printer — impact printer that forms images or text with a grid of pins striking an inked ribbon.
  • Tractor feed — mechanical system using holes along the paper edges to move and align paper.
  • Ribbon cartridge — inked fabric strip that transfers ink to paper when struck by pins.
  • Multi-part form — special paper allowing multiple copies from a single print through impact and chemical reactions.

Action Items / Next Steps

  • Review different printer types and compare their use cases.
  • Practice identifying dot matrix components and paper types.
  • Prepare questions on impact vs. non-impact printers for discussion.