How Does an Inkjet Printer Work?


Previously, we discussed how laser printers, and copiers, work. This time, let’s look at inkjet printers.

The premise is simple – inkjet printers drop tiny ink droplets onto the paper, where many drops create the desired text and image. The execution is quite a bit more complicated.

The Print Head

The most important part of any inkjet printer is the print head. It is also the most complex part. Inkjet print heads are equipped with an array of closely-arranged microscopic nozzles to ensure that they accurately spray the ink onto surfaces like canvas, paper, and fabric, among others.

Various print head technologies have been developed. Although the ultimate goal of getting the ink on to the page quickly, cleanly and efficiently is shared by every inkjet manufacturer, they have built their own technologies for their own devices.

Here are the 3 most common technologies used today:

Piezoelectric Technology

Piezoelectric ink cartridges work by sending a small electrical charge to the piezo crystal found behind the ink reservoir. This controls the flow of ink. By vibrating the crystals, an ink droplet is forced out to spray through the nozzle. When the crystal vibrates outward, it draws more ink from the reservoir to replace the sprayed ink.

Thermal Bubble Technology

Thermal Bubble technology uses heat. The resistors in the cartridge create the heat, which vaporizes the ink into a bubble. As the bubble expands, it pushes ink out of the nozzle. When the bubble pops, it makes a vacuum that pulls more ink to the cartridge head. Each bubble jet print heads contain 300 to 600 tiny nozzles; they can each fire a droplet. The ink used is mostly water-based, dye-based, and pigment-based.

Continuous Inkjet Technology

This technology is most often used at an industrial level – for marking and coding products and packages. A high-pressure pump pulls the ink from the reservoir via a nozzle, creating a continuous stream of ink – ideal for high-speed, exceptionally large print jobs. The ink droplets are formed by a charging electrode. When subjected to an electrostatic field, the ink droplets are deflected to the receptor material.

Ideal Uses Your Inkjet Printer

Ink tends to be more expensive when compared to toner, because it’s more complicated to make. Therefore, printing large volumes of black text is not the best option (stick with a laser printer for those jobs). Nor does glossy paper work well with ink, as it often rests on top of the page instead of sinking in, and is easily smudged. Inkjet printers, however, are ideal for:

• Paper that requires a slow print speed
• Duplexing label sheets
• High-quality color photographs

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