What is an inkjet printer?
An inkjet printer builds a page one horizontal band at a time. A printhead with hundreds of microscopic nozzles rides on a carriage across the paper, firing ink droplets, and the paper advances after each pass. Inkjets are inexpensive to buy, handle color and photos well, and suit homes and small offices. The trade-offs are a higher cost per page than laser, slower output on long text jobs, and ink that can dry in the nozzles when the printer sits unused.
How an inkjet prints
- The pickup roller pulls a sheet from the feeder or paper tray.
- Feed rollers position the sheet under the printhead.
- A stepper motor and carriage belt move the carriage, which holds the printhead and usually the cartridges, back and forth along a rail.
- The printhead fires droplets as it moves, and the rollers advance the paper for the next band.
- On models with a duplexing assembly, the sheet is drawn back in and turned over to print the second side.
Thermal vs. piezoelectric printheads
- Thermal (bubble jet): a tiny resistor heats the ink in each chamber until a vapor bubble forms and forces a droplet out. HP and Canon use this method.
- Piezoelectric: a piezo crystal flexes when voltage is applied and pushes the droplet out without heat. Epson uses this method.
Some printers build the printhead into each ink cartridge, so every cartridge change also replaces the head. Others use a fixed printhead with ink-only cartridges or refillable tanks; the head lasts longer but costs more to replace when it fails. Inks are either dye-based (vivid, but less resistant to water and fading) or pigment-based (more durable).
Maintenance
- Clean printheads: run the cleaning cycle from the printer menu or the maintenance tab of the driver, then print a nozzle check pattern. Each cycle uses ink, so run one or two and check the result before repeating.
- Replace cartridges: open the access door so the carriage moves to the change position, remove any protective tape from the new cartridge, and seat it until it clicks.
- Calibrate: run printhead alignment after installing a new head or cartridge, or when vertical lines look jagged or text looks doubled.
- Clear jams: with the printer off, open the access doors and pull the paper out slowly in the direction it normally travels so no torn pieces stay behind. Check the rear path and duplexer too.
Paper that will not feed often means a dirty or glazed pickup roller. Clean it with a lint-free cloth lightly dampened with water.
Troubleshooting
| Symptom | Likely cause and fix |
|---|---|
| Horizontal streaks, gaps or missing lines | Clogged nozzles: print a nozzle check and run a cleaning cycle |
| Wrong or missing colors | Empty or clogged color cartridge |
| Blurry text or jagged vertical lines | Printhead out of alignment: calibrate |
| Smearing | Wrong paper type setting, unsuitable paper, or pages handled before the ink dried |
| Paper not feeding or multipage misfeed | Dirty pickup roller, overfilled tray or the wrong paper weight |
| Grinding noise or carriage stall | Obstruction in the carriage path or a worn carriage belt |
Inkjet printer on the CompTIA A+ exam
Core 1 objective 3.8 lists the inkjet components (ink cartridge, printhead, roller and feeder) and four maintenance tasks: clean printheads, replace cartridges, calibrate and clear jams. Objective 5.6 covers symptoms such as paper jams, faded prints, lines on the page and grinding noise. Scenario cues: streaks or missing lines from an inkjet point to clogged nozzles and a cleaning cycle, while misaligned or doubled lines after a cartridge swap point to calibration. Know thermal vs. piezoelectric heads, and keep thermal inkjet separate from thermal printers, which use no ink and need heat-sensitive paper.