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.