The Effect of Ink Supply Pressure on Piezoelectric Inkjet

Abstract

Experimental and numerical analysis of the drop-on-demand inkjet was conducted to determine the jetting characteristics and meniscus motion under the control of the ink supply pressure. A single transparent nozzle inkjet head driven by a piezoelectric actuator was used to eject droplets. To control ink supply pressure, the pressure of the air in the reservoir was regulated by a dual valve pressure controller. The inkjet performance and the motion of the meniscus were evaluated by visualization and numerical simulation. A two-dimensional axisymmetric numerical simulation with the dynamic mesh method was performed to simulate the inkjet dynamics, including the actual deformation of the piezoelectric actuator. Numerical simulation showed good agreement with the experimental results of droplet velocity and volume with an accuracy of 87.1%. Both the experimental and simulation results showed that the drop volume and velocity were linearly proportional to the voltage change. For the specific voltages, an analysis of the effect of the ink supply pressure control was conducted. At the maximum negative pressure, −3 kPa, the average velocity reductions were 0.558 and 0.392 m/s in the experiment and simulation, respectively, which were 18.7 and 11.6% less than those of the uncontrolled case of 0 kPa. Therefore, the simulation environment capable of simulating the entire inkjet dynamics, including meniscus movement regarded to be successfully established. The average volume reductions were 18.7 and 6.97 pL for the experiment and simulation, respectively, which were 21.7 and 9.17% less than those of the uncontrolled case. In the results of the meniscus motion simulation, the damping of the residual vibration agreed well with the experimental results according to the ink supply pressure change. Reducing the ink supply pressure reduced the speed and volume, improved the damping of residual vibrations, and suppressed satellite drops. Decreasing ink supply pressure can be expected to improve the stability and productivity of inkjet printing.

Inkjet printing for smart electrochromic devices

“…In addition, droplet size and its velocity leaving the print head could be controlled by changing the drive voltage for customizing the droplet size and delivering material more precisely 66 . Piezoelectric DOD is more popular in the production of electronic components due to the wider variety of inks applicable without the limitation of bubble formation at high temperature 5,67,68 …”

Droplet Ejection by Pulsatile Airflow

“…Sometimes it enables the drop-on-demand (DOD) ejection. For a piezo droplet ejector, , the droplet volume, ejection frequency and velocity can be controlled by adjusting the voltage and frequency of the driving electric pulse. But the regulation range of the droplet size is rather limited.…”

“…For most active approaches, both the droplet volume and ejection velocity are usually simultaneously influenced by the actuation amplitude. So, they still cannot be individually regulated. ,, …”

“…So, they still cannot be individually regulated. 17,18,23 From above discussions, the droplet ejection technology still has much room for improvement regarding its control flexibility and application universality. In our previous studies, 24−28 we have demonstrated that external perturbation is a straightforward and efficient method for active droplet generation in pipe flows.…”

Editorial for the Special Issue on Recent Advances in Inkjet Technology

“…Their research focused on the excellent adhesion of inkjet-printed patterns and obtained good results. Kim et al [ 16 ] developed a computational model for simulating inkjet ejection, including pressure wave propagation and actuator motion. In addition, the ink supply effect on the inkjet performance and meniscus movement, which is rarely covered, was also studied.…”