0984
Input and Output Devices
Hardware · 4 question types
Exam Frequency Analysis
Past paper frequency (2018 to 2024)
This topic accounts for approximately 3% of your exam marks.
stable
Rare
Stable3%
Typically tested as 'give one use of…' or 'describe how this sensor works' questions.
Three kinds of printer often appear in comparison questions: inkjet, laser and 3D.
| Feature | Inkjet | Laser | 3D printer |
|---|---|---|---|
| How it works | Sprays liquid ink in tiny droplets through nozzles onto paper | Uses a laser to draw the page on a charged drum; toner sticks to the charged areas and is fused onto the paper by a hot roller | Deposits successive thin layers of melted plastic (or similar material) that stack up into a 3D shape |
| Output | 2D page (text or image) | 2D page (text or image) | 3D solid object |
| Material | Liquid ink in colour cartridges | Powdered toner (typically black plus 3 colours) | Filament of thermoplastic (PLA, ABS) or resin |
| Speed | Slow | Fast | Very slow (objects take hours) |
| Print quality | High-quality colour photos | Sharp text; colour quality depends on model | Layered surface; not as smooth as injection moulded |
| Cost per page / item | Higher (ink is expensive) | Lower for high volume | High for each object |
| Cost of the printer | Cheap | Mid-to-high | Mid-to-high for desktop models |
| Typical use | Home printing, photo printing, low-volume colour | Offices, schools, anywhere with high-volume monochrome printing | Prototyping, custom parts, education, medicine |
Why the three look so different
- Inkjet is cheap to buy but expensive to run because of the ink. Best for low-volume colour at home.
- Laser is more expensive to buy but cheaper per page because toner lasts longer. Best for offices that print thousands of pages a month.
- 3D printers do something completely different: they output three-dimensional objects rather than printed paper. The internal mechanism is unrelated to inkjet or laser.