The basic principle of inkjet printing
Digital inkjet printing works by applying an external force to the ink that is ejected through the nozzle onto the fabric to form a color point. Digital jet printing is a digital image jetting technique that uses digital technology to control the spray and non-spray of the nozzle, the color of the ink to be sprayed, and the movement in the X-direction to ensure the desired image and color are formed on the surface of the fabric. An important technical indicator for digital printing is resolution (referred to as dpi), which refers to the number of dots per inch. In the case of inkjet printing, different base fabrics have different resolution requirements. In general, when the dpi is 180 to 360, the image is clear. For a very fine image dpi can reach 360 ~ 720. After the resolution is increased, the nozzle injection frequency and orientation accuracy are higher. The Digital Printing Zone, which has no borders, has also summarized some discussions about the resolution of digital printing. The principle of jet printing:
1. Continuous Injection CIJ (continuous Ink Jet)
The principle of continuous jetting is to apply a high-frequency oscillating pressure to the ink to eject ink from the nozzle to form a uniform continuous droplet flow. An electric field that changes in synchronism with the pattern photoelectric conversion signal is provided at the nozzle. The ejected droplets are selectively electrified in the charging electric field. When the droplet stream continues to pass through the deflecting electric field, the charged droplets are deflected by the electric field, and the uncharged droplets continue to maintain a straight flight state. The droplets flying in a straight line cannot reach the substrate to be printed and are recovered by the liquid collector. The charged droplets are ejected onto the substrate to be printed.
2. Drop on Demand as needed
The working principle of the on-demand jet printing system is that when printing is required, the system applies high-frequency mechanical force and electromagnetic thermal shock to the color ink in the nozzle, so that tiny droplets are formed to be ejected from the nozzle, and the jet is controlled by the computer. Go to the set pattern. The most popular application for on-demand jetting is thermal inkjet technology, which relies on thermal pulsation to produce ink droplets. A heating resistor wire is controlled by a computer to a specified temperature, causing the ink to be ejected from the nozzle after vaporization (fog). Another DOD technology is a piezoelectric injection system in which a potential is imposed on a piezoelectric material by a computer to cause compression of the piezoelectric material in the direction of the electric field and expansion in the vertical direction to eject the ink.
