Lecture Notes: Dot Matrix Printers

Introduction to Dot Matrix Printers

• Dot matrix printers are a type of impact printer.
• Impact printers create marks on paper by pressing against a ribbon.
• The printed output consists of small dots forming characters, visible on close inspection.

Advantages of Dot Matrix Printers

• Multiple Copies: Suitable for creating multiple copies using carbon paper.
• Cost Efficiency: Lower cost per page due to minimal ink usage as only the ribbon is required.

Disadvantages of Dot Matrix Printers

• Noise: Impact on paper creates considerable noise.
• Resolution: Lower resolution, not suitable for graphical outputs.

Printing Mechanism

• Components:
  • Paper
  • Ribbon placed in front of the paper
  • Printhead on the other side of the ribbon
• Printhead Details:
  • Moves back and forth across the paper.
  • Uses tiny pins (24 pins) to create characters.
  • Contains a heatsink for heat dissipation.

Ribbon Cartridge

• Ribbons are long fabric strips used to transfer ink.
• Easy replacement process.
• Compatibility: Need to match the ribbon model to the printer model.
• Structure: One long piece of fabric inside the cartridge.

Paper Feeding System

• Tractor Feed System:
  • Holes on paper sides for guided feeding.
  • Perforations allow page separation.
• Installation:
  • Align paper with tractor guides and lock in place.
  • Use paper feed button to pull paper through printer.
• Paper Type:
  • Long, folded paper with perforations.
  • Green bar paper used for large format printing, common with mainframes.

Special Paper Types

• Green Bar Paper:
  • Associated with mainframe printing.
  • Contains built-in tractor feeds on sides.
  • Large format (11 inches high by 14 inches wide).