# Color Printer Internals

By akhil kv

Topic: Machines

[Open the interactive Jig](https://ask.jig.com/j/XwH9PoEIIa76)

## Guide

### 1. A printer, opened up

This colour inkjet printer has its cover taken off so you can see inside\. A stack of paper waits at the back, and a little carriage of ink sits on a steel rod\. Press the round Power button on the front, or drag the desk to look around\.

A home inkjet like this is about 37 cm wide and weighs around 4 kg\.

### 2. Waking up

Electricity runs from the power cord into the power supply, then to the main circuit board, the printer's brain\. The board checks the motors: the carriage slides out of its parking spot and back\. The green light means ready\.

### 3. One sheet at a time

A rubber pickup roller turns and drags just the top sheet off the stack\. The feed roller grips it and pulls it under the carriage, to the line where printing begins\.

Rubber grips the paper; smooth plastic below lets the other sheets slip\.

### 4. The flying carriage

A motor turns a toothed belt that pulls the carriage left and right along the steel rod\. A clear striped strip tells the board exactly where the carriage is\. After each pass the rollers nudge the paper forward a tiny step\.

Watch the yellow dashes: the flat ribbon cable carries firing signals to the printhead\.

### 5. Inside one nozzle

Under each cartridge are hundreds of nozzles thinner than a hair\. A tiny heater flashes hot for a few millionths of a second\. A bubble of ink vapour pops up and pushes one drop out onto the paper\.

Shown about 1,000 times bigger\. A real drop is just 1 to 1\.5 picolitres, a billionth of a millilitre\.

### 6. Four inks make every colour

The printer carries only cyan, magenta, yellow and black\. Tiny dots of each sit side by side and on top of each other\. Your eye blends them into reds, greens and every other colour\. Pick one ink to see its dots alone\.

Dots are drawn much larger here than on a real page\.

### 7. Print a whole page

Now everything works together\. The sheet is picked, the carriage races back and forth, and the picture grows one band at a time\. When the last row is done, the exit rollers push the page out onto the tray\.

### 8. Park and rest

When the work is done, the carriage slides home and a soft rubber cap presses against the nozzles\. The cap keeps the ink from drying out until next time\. Now it's your turn: try the Power and Print buttons on the front\.

A wiper blade beside the cap cleans the nozzle plate\.