Inkjet printing technologies for home tasks

Inkjet printing is a non-contact printing method that creates an image or text by precisely depositing tiny drops of ink onto paper
. Inkjet printing technology has been around for more than 50 years, and throughout its existence, printers have gone from expensive to affordable home devices.

технологии струйной печати разработаны несколькими производителями

Inkjet printing technologies in home printers

Inkjet printing is based on several technologies
. The most common are piezoelectric, thermal and bubble

All inkjet printing methods have a common basis, set out back in 1833. It was then that a French researcher came to the conclusion that liquid seeping through a microscopic hole turns into a perfectly smooth drop. In 1951, the technology was used commercially by Siemens. The first results that were achieved for inkjet printing have little in common with modern analogues.

Researchers see such printing as a technology of the future and are constantly trying to make it more advanced. Thus, in the early 1960s, continuous inkjet printing appeared. Pressure is used to provide a continuous flow of droplets, which can be controlled using an electrical charge. But this method has its drawbacks: frequent failures, high price, low print quality.

Continuous Inkjet Technology

как работает принтер по непрерывной технологии струйной печати

When printing with this technology, pressurized ink enters the nozzle and is separated into droplets by rapidly changing the pressure. Pressure fluctuations cause a change in the diameter and speed of the paint jet emerging from the nozzle, which is divided into individual droplets under the influence of surface tension forces.

Drops of paint escaping from the nozzle pass through a charged electrode, the voltage on which is changed by a control signal. The stream of droplets then enters the space between the two deflecting electrodes. Depending on the charge received previously, individual drops change their trajectory in different ways. This effect allows you to control both the position of the printed dot and its presence or absence on the paper. In the latter case, the drop is deflected so much that it ends up in a special catcher.

Such systems allow printing dots with a diameter of 20 microns to one millimeter. A typical dot size is 100 microns, which corresponds to a droplet volume of 500 picoliters.

Pulse inkjet technology

Unlike continuous printing technology, there is no constant pressure in the ink volume, and pressure pulses are generated when it is necessary to create a drop. The control elements are less complex to manufacture, but a pressure generating device three times more powerful is required. The diameter of the droplets in this type of printing ranges from 20 to 100 microns, which corresponds to a volume of 5 to 500 picoliters. Depending on the method of creating a pressure pulse in the ink volume, a distinction is made between piezoelectric and thermal inkjet printing.

Piezoelectric printing

при пьезоэлектрической печати от Эпсон пьезокристалл деформируется при поступлении электрического импульса

To implement piezoelectric
method, a piezoelectric element is installed in each nozzle, connected to the ink channel by a diaphragm. Under the influence of an electric field, the piezoelectric element is deformed, due to which the diaphragm contracts and expands, squeezing a drop of ink through the nozzle. A similar drop generation method is used in Epson inkjet printers.

This technology: the piezoelectric effect is well controlled by the electric field, which makes it possible to quite accurately vary the volume of the resulting droplets.

: when modulating the volume of drops, not only the volume changes, but also the speed of the drop, which causes point positioning errors when the head moves. The production of print heads for piezoelectric technology turns out to be too expensive per head, so in Epson printers the print head is part of the printer and the cost can be up to 70 – 80% of the total cost of the entire printer. Failure of such a head requires serious service.

Thermal inkjet printing

принцип работы термоструйной печати состоит в нагревании элемента и двух пластин между которыми находятся чернила

For the implementation of thermal jet
method, each of the nozzles is equipped with one or more heating elements, which heat up to a temperature of about 600 degrees Celsius in a few microseconds. The gas bubble that appears during sudden heating pushes a portion of ink through the outlet hole.

When the current stops, the heating element cools down, the bubble collapses, and another portion of ink takes its place.
from the input channel.

The process of creating droplets in thermal print heads after applying a pulse to the heater is almost uncontrollable, so dynamic control of the droplet volume is very difficult.
This technology: thermal printheads have the highest ratio of performance to unit production cost, so the thermal inkjet printhead is usually part of the cartridge and when replacing the cartridge with a new one, the printhead is automatically replaced.

The use of thermal print heads requires the development of special ink that can evaporate quite easily without ignition and is not subject to destruction due to thermal shock.

Advantages of inkjet printing technology

Inkjet printing technology has its advantages, including:

  • absence of a preparatory stage before printing, allowing you to print small runs in a short time;
  • low cost with high image quality;
  • the ability to print on various surfaces: paper, fabric, plastic, etc.;
  • one step printing and programming process can be carried out.

Disadvantages of inkjet printing technology

Disadvantages of inkjet printing for home applications include slight color deviation and low color accuracy. This is why if you want to print a color image, it is better to print a test version first. And then, after making sure that it meets all the requirements, begin printing additional copies. Inkjet printing is one of the most affordable. This technology is not expensive, so anyone can use it.