Epson's Micro Piezo printheads are equipped with Variable Sized Droplet Technology (VSDT). This technology precisely controls the voltage that drives the piezoelectric elements so that the same nozzle can eject ink droplets of various sizes, as needed.
The result is that images can be rendered beautifully at high speed, with delicate brightness levels and smooth gradations with reduced graininess.
Inkjet printers eject a tremendous number of ink droplets mostly using one of two methods. One is the serial head method, in which the print head is rapidly moved back and forth over the paper or other medium as it is fed forward in small increments. The other is the linehead method, in which a printhead that is the same width as the paper remains stationary while the paper is fed forward.
Both methods can produce high-quality prints by ejecting smaller ink droplets.
However, when the ink droplets become very small, serial printheads must be scanned back and forth a greater number of times in order to print fill areas, which makes it difficult to increase printing speed. In linehead printing, meanwhile, the printhead used to need nozzles of different diameters for each size of ink droplets. This need resulted in larger printheads.
To solve this problem, Epson came up with a method to control the volume of ink in ejected droplets. This method achieves both beautiful gradations and high speed because it enables each nozzle to eject ink droplets with a range of sizes, from large to small.
Micro Piezo printheads use the mechanical motion of piezoelectric elements that contract under an applied voltage to eject droplets of ink. The volume of ink in each droplet is controlled by precisely controlling the voltage applied to the piezoelectric elements.
Epson uses VSDT to eject ink droplets of various sizes from the same nozzle. Droplet volume ranges from as little as 1.5 picolitres to as much as 32.5 picolitres. VSDT enables Epson printers to produce beautiful images rendered at high speed with delicate brightness, smooth gradations, and reduced graininess.