Inkjet printers turn colored liquid ink into fine particles through nozzles and spray them onto printing paper. Some inkjet printers have three or four print heads to print yellow, magenta, and black and black; some share a single head, and Four-color printing.
There are two main technologies used in inkjet printers: continuous inkjet technology and random inkjet technology. Early inkjet printers and current large-format inkjet printers used continuous inkjet technology, while the popular inkjet printers currently on the market generally use random inkjet technology. Continuous inkjet technology is represented by charge modulation. In random inkjet systems, ink is ejected only when printing is needed, so it is also called on-demand.
Continuous inkjet Continuous inkjet technology is typified by a charge modulation type. This inkjet printing principle uses a piezoelectric driving device to apply a fixed pressure to the ink in the head to make it continuously eject. For recording, the vibration signal of the oscillator is used to excite the jet to generate ink droplets, and the size and pitch of the ink droplets are controlled. The printed information from the character generator and the analog modulator controls the charge on the control telegram to form charged and uncharged ink droplets. The deflection electrode changes the flying direction of the ink droplets, so that the ink droplets to be printed are printed. Fly to paper to generate character / graphic records. Ink droplets not participating in the record are recovered by the catheter. For deflection electrodes, some systems use two pairs of mutually perpendicular deflection electrodes to perform two-dimensional deflection on the ink droplet printing position; some systems use multi-dimensional control on deflection electrodes, that is, multi-dimensional deflection. This continuous cycle inkjet system. It can generate high-speed ink droplets, so the printing speed is high, and plain paper can be used. Different print media can obtain high-quality print results, and it is easy to realize color printing. However, the structure of this inkjet printer is more complicated than that of the random type: a pressurizing device is required for the ink, and a recycling device is required for the terminal to recover the non-participating records. And the working method is not efficient enough and imprecise. Inkjet printers using this technology are rarely seen.
Random inkjet In the random inkjet system, ink is ejected only when printing is needed, so it is also called on-demand. Compared with the continuous type, it has a simple structure, low cost, and high reliability. However, due to the influence of jet inertia, the ink droplet ejection speed is low. In this random inkjet system, in order to make up for this shortcoming, many random inkjet printers use a multi-nozzle method to increase printing speed. There are two main types of random inkjet technology: micro-piezo type and thermal bubble type:
Thermal Bubble Inkjet Technology Inkjet printers generally use thermal bubble inkjet technology. The ink is sprayed onto the printing paper to form ink dots by heating, expanding, and compressing the ink in a short period of time. print. In addition to the size of the ink droplets, the consistency of the shape and density of the ink droplets will have a significant impact on image quality, and the direction and shape of the ink dots generated at high temperatures are not easy to control. important. The principle of thermal bubble inkjet printing is to fill the ink into a very tiny capillary tube, and quickly heat the ink to the boiling point through a miniature heating pad. This creates a very tiny vapor bubble, which expands and ejects a drop of ink to the tip of the capillary. When the heating is stopped, the ink cools, causing the steam to condense and contract, thereby stopping the ink flow until the next time steam is generated and an ink droplet is generated.
Micro Piezo Technology The micro-piezo technology divides the ink droplet control in the ink-jetting process into three stages: before the ink-jet operation, the piezoelectric element first shrinks slightly under the control of the signal; then, the element generates a large extension and the ink droplet Push out the nozzle; the moment the ink droplet is about to fly away from the nozzle, the component will shrink again, and the ink liquid level will be contracted cleanly from the nozzle. In this way, the ink droplet liquid level is precisely controlled, and each ink droplet ejected has a perfect shape and a correct flying direction.
The basic working principle of an inkjet printer is to first generate small ink droplets, and then use the inkjet head to guide the small ink droplets to a set position. The smaller the ink droplets, the sharper the printed picture.