Resource Cheatsheet
A+ Core 1 3.8: Impact Printers
A+ Core 1 3.8 — dot-matrix print heads, ribbons, tractor-feed paper, green bar paper, and multi-part carbonless copies.
- Updated
- Reading time
- 3 min read
- Detail
- A+ Core 1
- Detail
- Impact Printers
On this page
In one line: a dot-matrix printer strikes a pin matrix through a ribbon onto tractor-fed paper — noisy and low-res, but cheap per page and the only type that produces carbon-copy multi-part output in one pass.
Companion to: Professor Messer A+ Core 1 (220-1201), Section 3, objective 3.8. The full version is the Impact Printers class notes; the section overview is the Section 3 sheet.
How it works
| Component | Role |
|---|---|
| Print head | Moves back and forth per line; holds the pin matrix; runs warm (large heat sink) |
| Ribbon | Continuous loop in a replaceable cartridge; full page width; size varies by make/model |
| Tractor feed | Sprockets engage edge holes; misalignment/missed holes → jam |
| Paper | Tractor/fanfold paper (continuous or perforated); green bar paper was common for source-code printouts |
Strengths vs weaknesses
| Strength | Weakness |
|---|---|
| Can produce carbon copies (multi-part) | Noisy |
| Low cost per page | Low resolution |
→ mostly niche use today (multi-part forms, high-volume plain text).
Multi-part paper
- Carbon paper (traditional) or micro-encapsulated ink + clay reaction (modern, cheaper): ink capsules on the back of sheet 1 react with clay on sheet 2, creating a copy without the head touching sheet 2.
- Caution: the inks/dyes and clay can irritate skin with extended handling.
- Many orgs now just print a separate copy on another printer instead — cheaper and easier than maintaining ribbons/paper/mechanics.
🔐 Security notes
- Legacy printers = legacy connectivity: often on old parallel/serial links to unpatched hosts — isolate/segment rather than leave exposed on the network.
- Physical simultaneity has value: multi-part carbon-style copies are harder to selectively forge after the fact than two separately printed pages — understand why a process may still rely on one.
- Spent ribbons hold data: every character struck is physically imprinted (in reverse) and can in principle be read back — dispose of sensitive ribbons securely, like printed waste.
Practice drills
1. How does a dot-matrix printer form characters?
A matrix of pins in the print head strikes a ribbon, transferring ink to the paper as small dots.
2. One advantage and two disadvantages of impact printers?
Advantage: can produce carbon copies (and low cost per page); disadvantages: noisy and low resolution.
3. Why does the print head need a heat sink?
Repeated pin strikes make it run warm; the heat sink dissipates that heat.
4. What is a tractor feed, and what happens if the holes misalign?
Sprockets pull paper via edge holes; misaligned or missed holes cause a paper jam.
5. What was green bar paper commonly used for?
Printing source code, giving programmers an easier-to-review printout.
6. How does carbonless multi-part paper create a copy?
Micro-encapsulated ink on the back of the top sheet reacts with a clay coating on the sheet below.
7. Why have many organisations moved away from multi-part impact printing?
Printing a separate copy on another printer is now cheaper and easier than maintaining a dot-matrix printer’s ribbons, paper and moving parts.
Key takeaways
- Pin matrix + ribbon = dots on the page; head sweeps per line, page advances.
- Ribbon = one continuous loop in a quick-swap cartridge; tractor feed needs holes aligned or it jams.
- Green bar / fanfold paper is the classic tractor-feed look.
- Multi-part paper (carbon or ink+clay) makes copies in one pass — but can irritate skin, and reprinting elsewhere is now often simpler.
- Security: legacy connectivity to isolate; spent ribbons carry a physical data imprint — dispose securely.