Overview
This lecture explains the key features, mechanisms, and usage of dot matrix (impact) printers, highlighting their printing process, components, paper handling, and advantages and disadvantages.
Dot Matrix Printer Basics
- Dot matrix printers are a type of impact printer that create output by pressing pins against an ink ribbon onto paper.
- Each printed character is formed by small dots made by the pins of the printhead.
- Ideal for making multiple copies using carbon paper due to impact printing.
Advantages and Disadvantages
- Low cost per page since only ribbon ink is required, not special toner or ink cartridges.
- Noisy operation due to the physical impact during printing.
- Lower print resolution compared to other printer types, not suitable for high-quality graphics.
- Best suited for letters and numbers, not detailed images.
Printing Mechanism and Components
- The printhead, containing multiple pins (e.g., 24 pins), moves across the page to create output.
- Printhead has a heatsink to dissipate heat generated during printing.
- Ribbon is a long fabric strip that holds ink, positioned between printhead and paper.
- Ribbons are easy to replace but must be compatible with the specific printer model.
Paper Handling and Tractor Feed
- Uses tractor feed mechanism: paper has holes along the edges that align with guides in the printer.
- Paper is usually a continuous sheet with perforations for easy separation into individual pages.
- Tractor feeds can be adjusted for precise alignment and removed after printing.
- Common paper includes large-format "green bar" paper (11"x14"), often associated with mainframe printing.
Key Terms & Definitions
- Impact Printer — printer that creates images by physically striking a ribbon against paper.
- Dot Matrix — grid of pins in the printhead creating characters via individual dots.
- Printhead — moving component containing pins that form letters and images.
- Ribbon — ink-soaked fabric strip transferring ink to paper.
- Tractor Feed — paper moving system using holes along sheet edges for precise control.
- Green Bar Paper — large-format, continuous paper with colored bands and tractor-feed holes.
Action Items / Next Steps
- Review the mechanism and parts of a dot matrix printer.
- Be able to explain the differences between impact and non-impact printers.
- Check assignment/exam requirements regarding printer types.