Inkjet printing

Principle of operation

The principle of operation of inkjet printers is similar to matrix printers in that the image on the medium is formed from dots. But instead of heads with needles, inkjet printers use a matrix that prints with liquid dyes. Dye cartridges come with a built-in printhead - this approach is mainly used by Hewlett-Packard (HP), Lexmark (Lexmark International Rus). Firms in which the printing matrix is a part of the printer, and replaceable cartridges contain only dye. With a long simple printer (a week or more), the residual dye on the nozzles of the printhead dries. The printer itself can automatically clean the printhead. However, it is also possible to force cleaning of nozzles from the corresponding section of the printer driver configuration. When cleaning the nozzles of the printhead, an intense consumption of dye occurs. Especially critical is the clogging of the nozzles of the printing matrix of the Epson, Canon printers (Canon Ru). If it is not possible to clean the printhead nozzles by standard printer tools, further cleaning and/or replacement of the printhead is carried out in repair shops. Replacing a cartridge containing a printing die with a new one does not cause problems.

A continuous ink supply system is used to reduce printing costs and improve other printer characteristics.

Types of dye supply

Ink jet printers print heads are created using the following dye supply types:

• Continuous giving (Continuous Ink Jet) - supply of dye during the press happens continuously, the fact of hit of dye is defined on the sealed surface by the dye stream modulator.

In the technical implementation of such a printhead, a dye is supplied to the nozzle under pressure, which at the outlet of the nozzle is divided into a sequence of micro drops (a volume of several dozen picoliters), which additionally communicate an electric charge. The dye flow is divided into drops by a piezocrystal located on the nozzle, on which an acoustic wave is formed (with a frequency of tens of kilohertz). Deflection of droplet flow is performed by electrostatic deflection system (difflector). Dye droplets that do not have to reach the sealing surface are collected in the dye collector and are typically returned back to the main dye tank. The first inkjet printer manufactured using this dye supply method was released by Siemens in 1951.

• Drop-on-demand - Dye is supplied from the nozzle of the printhead only when the dye really needs to be applied to the nozzle area of the surface to be sealed. It is this method of dye supply that is most widely used in modern inkjet printers.

At the moment, there are two technical implementations of this dye supply method:

• Piezoelectric Ink Jet - a piezoelectric crystal with a diaphragm is located above the nozzle. When an electric current is supplied to the piezoelectric element, it bends and pulls the diaphragm behind it - a drop is formed, which is subsequently pushed onto the paper. Widely used in Epson inkjet printers. The technology allows you to change the size of the drop.

• Thermal Ink Jet, also called BubbleJet - Developer - Canon Company. The principle was developed in the late 1970s. A microscopic heating element is located in the nozzle, which, when electric current passes, is instantly heated to a temperature of about 500 ° C, when heated in the ink, gas bubbles are formed (eng. - bubbles - hence the name of the technology), which push liquid drops from the nozzle onto the carrier.

Market Assessment

2020:4 manufacturers control almost 100% of the inkjet printer market

In 2020, 58.55 million inkjet printers were sold worldwide, which is 2.9% more than a year ago. Such data in August 2021 were released by the research company IDC. More details here.

Design

Inkjet printing is divided into the following subsystems:

• Carrier system
• Power supply unit
• Paper Feed System
• Printhead with mechanics for positioning
• Ink cartridge
• Printhead Nozzle Ink Scrubbing System
• Control system

Main article: Printing devices (market)