Printer Repair — Detailed Notes for Interns

1. Types of Printers

Type How It Works Common Uses
Inkjet Sprays liquid ink through microscopic nozzles onto paper. Photo, color prints.
Laser Uses electro-photographic process (toner + heat + drum). High-volume text, offices.
Dot Matrix Impact pins strike ink ribbon. Carbon copies, receipts.
Thermal Heat reacts with special paper. Labels, POS systems.

2. Printing Process — Laser Example

  1. Processing: PC sends data → print language interpreted.
  2. Charging: Corona wire applies uniform negative charge to drum.
  3. Exposing: Laser discharges areas to create image pattern.
  4. Developing: Toner attracted to discharged areas.
  5. Transferring: Paper given positive charge; toner moves to page.
  6. Fusing: Heat + pressure rollers bond toner to paper.
  7. Cleaning: Drum scraped and neutralized for next job.

🧠 CFUs: Ask students to label each stage on a diagram._

3. Routine Maintenance Tasks

Task Purpose Frequency
Clean rollers & paths Prevent jams, streaks Monthly
Replace toner/ink Maintain print quality As needed
Calibrate color & alignment Ensure accurate output Every cartridge change
Empty waste-toner bottle Avoid overflow Every 2–3 cartridges
Update firmware Fix bugs, security Quarterly

4. Troubleshooting Guide

Symptom Likely Cause Quick Fix
Paper jam Dirty/ worn rollers Remove paper → clean rollers w/ lint-free cloth
Faded prints Low toner / clogged nozzles Replace cartridge or run cleaning cycle
Ghosting Drum not fully discharged / fuser issue Replace drum → check fuser
Streaks / lines Dirty corona wire Gently clean with swab or built-in cleaner
Blank pages Empty toner / transfer corona not working Replace toner → inspect transfer unit
Smudging Fuser not hot enough Check fuser temp → replace unit if needed
Paper wrinkled Moisture / wrong tray setting Replace paper → check tray alignment