A piezoelectric device is a crucial component in inkjet printing technology, especially in industrial inkjet printers. It is used to control and precisely manipulate the ejection of ink droplets from the print head onto the printing substrate (paper, fabric, plastic, etc.). Here's how a piezoelectric device controls inkjet droplet ejection in industrial printing:
Principle of Piezoelectricity: Piezoelectric materials are those that generate an electric charge in response to mechanical stress or deformation and, conversely, deform in response to an applied electric field. This property allows them to convert electrical energy into mechanical motion and vice versa.
Piezoelectric Actuators: In an industrial inkjet print head, there are small chambers or nozzles that contain ink. These chambers are equipped with piezoelectric actuators, which are typically made from piezoelectric ceramics or polymers. When a voltage is applied to the piezoelectric material, it undergoes mechanical deformation (expands or contracts), causing the volume of the chamber to change.
Ink Ejection Process: The ink in the chamber is under a certain pressure. When the piezoelectric actuator contracts or expands in response to the applied voltage, it changes the volume of the chamber. This change in volume creates a pressure wave within the ink, leading to the ejection of an ink droplet from the nozzle. The size and velocity of the droplet are controlled by the magnitude and duration of the voltage pulse applied to the piezoelectric actuator.
Drop-on-Demand (DOD) Printing: This mechanism is known as "Drop-on-Demand" (DOD) printing, as ink droplets are ejected only when needed, allowing for precise control over droplet placement on the substrate. This level of control is essential for producing high-quality prints, especially in industrial applications where accuracy and consistency are paramount.
Multiple Nozzles: Industrial inkjet print heads often consist of an array of individual nozzles, each with its own piezoelectric actuator. By controlling the voltage applied to each actuator independently, the printer can control the timing and positioning of ink droplet ejections from different nozzles. This enables the formation of characters, images, and patterns on the printing substrate.
Gray-Scale Printing: The precise control provided by piezoelectric actuators also allows for gray-scale printing, where the size of the ejected droplets can be varied to produce different levels of color intensity or shades of gray.
In summary, a piezoelectric device in an industrial inkjet printer plays a critical role in controlling ink droplet ejection through its ability to convert electrical signals into mechanical motion. This technology enables high-resolution, high-quality printing with precise control over droplet placement and size, making it suitable for various industrial and commercial printing applications.