A piezoelectric device is commonly used in industrial inkjet printing technology to control the ejection of droplets from the printhead onto a substrate (such as paper, fabric, or plastic) to create printed patterns or images. This technology is widely used in various applications, including commercial printing, packaging, textiles, and more. Here's how a piezoelectric device controls droplet ejection in industrial printing:
Printhead Design: The printhead is a critical component in inkjet printing. It contains tiny nozzles through which the ink droplets are ejected onto the substrate. Each nozzle corresponds to a single droplet.
Piezoelectric Actuator: A piezoelectric device, usually in the form of a piezoelectric crystal, is integrated into each nozzle of the printhead. A piezoelectric material generates an electric charge in response to mechanical stress or pressure. In this application, the piezoelectric actuator is designed to deform when an electric voltage is applied to it.
Ink Reservoir: The printhead is connected to an ink reservoir containing the ink that needs to be printed.
Droplet Ejection Process:
Idle State: In the idle state, the piezoelectric actuator is in its natural position, and the nozzle is closed. There's no ink ejection.
Ink Ejection Preparation: When a printing command is given, a specific voltage is applied to the piezoelectric actuator. This voltage causes the piezoelectric material to deform or contract. As a result, the nozzle opens slightly, creating a small chamber between the ink reservoir and the nozzle.
Ink Filling: The opening of the nozzle creates a low-pressure region in the chamber, which draws ink from the reservoir through capillary action. The chamber fills with ink, and this ink is now ready to be ejected.
Droplet Ejection: To eject a droplet, the voltage across the piezoelectric actuator is rapidly increased. This causes the piezoelectric material to deform even more, rapidly decreasing the volume of the chamber. The sudden decrease in chamber volume increases the pressure inside the chamber, forcing the ink out of the nozzle in the form of a droplet. The size of the droplet can be controlled by adjusting the magnitude and duration of the applied voltage.
Multiple Nozzles: A printhead usually contains a large number of nozzles arranged in a matrix. By controlling the voltage applied to each individual piezoelectric actuator, precise control over which nozzles eject ink at any given moment can be achieved. This allows for high-resolution printing and the formation of intricate patterns.
Image Formation: As the substrate moves under the printhead, the controlled ejection of droplets onto specific positions creates the desired image or pattern. By coordinating the ejection of different color inks and the movement of the substrate, full-color images can be produced.
In summary, piezoelectric devices in industrial printing technology provide precise control over droplet ejection, enabling high-resolution and high-quality printing on various substrates. The ability to quickly change the voltage across the piezoelectric actuators allows for rapid ink ejection and the creation of complex images or patterns.