How does an Inkjet printer work?

We need to print a lot of documents in the office or at home. The printing is easy; press the print button on the laptop screen, and you are ready to go. Your Inkjet printer will print whatever your command says. However, the technology behind it is a bit complex but works effortlessly. Here, we will explain in detail how an inkjet printer works.

Inkjet Printer Printhead
Inkjet Printer Printhead

First of all, the Inkjet printer on the same lines as a dot-matrix printer. Surprised right? Yes, you heard it right. The only difference in the case of the Inkjet printer is the dot size. The dot size is so small that the human eye can’t recognize it as a dot. So, it makes a huge difference. However, the Inkjet printer’s printing quality is excellent when you compare it to a dot-matrix printer.


The Inkjet Printer contains thousands of microscopic nozzles that send out ink on the paper. In general, these nozzles are 10 micrometers or 10 microns in diameter. That equates to 1/10th of human hair dimeter. So, the nozzles are microscopic. Manufacturing such nozzles is a challenge in itself and requires high precision fabrication.

Furthermore, placing the nozzles side-by-side requires a high level of accuracy. Such accuracy requires lots of precision as accurately placing of these nozzles decides the final print quality in inkjet printers.

Besides, all these nozzles are placed together on a carriage assembly that moves. The typical speed of carriage moving is greater than one meter per second across the entire paper back and forth. Typically these nozzles are closer to the paper, approx. one millimeter away from the paper. The printer discharges the ink on the paper at the speed of 5-10 meters per second.

Working of Inkjet Printer

The Inkjet printer works by injecting ink from the nozzle on a paper at high speed. The nozzle injects the ink by applying pressure on the ink. The pressure pulse is generally created by two methods – piezoelectric and thermal bubble.

First of all, the piezoelectric method uses piezoelectric materials that deform when the small pulse of electric current passes through them. Generally, these materials are placed on one of the walls of the ink channel. Any deformation in the materials leads to pushing the ink outside the nozzle. This deformation squeezes the ink channel, ultimately creating a pressure pulse. All this happens in just microseconds.

Furthermore, the second method is the thermal bubble method. The thermal bubble involves heating of ink and creating a vapor bubble. The square-shaped heater is placed along the ink channel. This heater gets activated when the pulse of current passes through the heater. So, this heat is enough to boil the ink along the ink channel.

In inkjet printer, the ink closer to the heater boils quickly, creating a vapor bubble. This vapor bubble then expands a thousand times. As a result, the expanding bubble creates a pressure pulse, emitting out ink outside the nozzle. Once the bubble collapses, the ink’s surface tension pulls more ink inside the nozzle, and it’s now ready for the next ink ejection.

Ink Quality

Besides, the ink performance plays the most critical role in Inkjet printers. The ink must be resistant to thermal decomposition. As the ink flows from a small nozzle, it should be excellent in quality for smooth performance.

Besides, the ink should dry very fast once it spreads on the paper. Firing from every nozzle is essential to keep nozzles working. Nonworking of the nozzles may lead to clogging. So, the printer keeps firing ink from different nozzles. The general dot density is 600-1200 dots per inch in Inkjet printers. However, the dot size is 10-20 micrometers in diameter. Such small dots are almost invisible to the human eye. Thus, you see the high print quality.

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Inkdot placement

Furthermore, the accurate placement of ink dots is essential for high-quality prints. The optical encoders precisely control the dot position on paper. It consists of a transparent code wheel, a light-emitting diode, and a photodetector. This code strip has immense importance in the Inkjet printer. It consists of precision black strips on a thin sheet of clear plastic.

This strip sits between the light emitter and light detector. Light beam interruption occurs as the carriage passes along each stripe. The photodetector detects it and creates a synchronization pulse that ultimately controls the ink’s release explained earlier. So, ink drops are printed with precision even if the carriage slows down as it comes to the edge of the paper.

Furthermore, the dot’s location along the paper sheet is controlled by nozzle pitch (distance between nozzles) and second encoder. The second encoder precisely controls the paper advance after each pass of the carriage along with the paper. The second encoder controls paper advance distance entirely.

Advantages of Inkjet printer

The inkjet printer creates excellent print quality. We can use some glossy paper types to achieve the feel of photographs. So, inkjet printers are great as they are less expensive to purchase and produce high-quality prints.

In conclusion, the Inkjet printer’s working is a combination of many parts working together, and it is not as simple as it looks. I hope next time you print, you will know what is happening behind the scenes. Happy printing.

Image Courtesy: Hp

Watch how does inkjet printer work?

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