Fig. 1. PiXDRO LP50 inkjet printing system. (a) Photograph of entire PiXDRO LP50 inkjet printing system; (b) diagram of PiXDRO LP50 printhead and module

Fig. 2. Driving voltage trapezoidal pulse wave of inkjet printing printhead module

Fig. 3. Variation in velocity of ink droplets ejected by 10 randomly numbered nozzles with driving voltage. (a) Variation in velocity of ink droplets ejected by 10 randomly numbered nozzles with driving low voltage V_L; (b) variation in velocity of ink droplets ejected by 10 randomly numbered nozzles with driving high voltage V_H

Fig. 4. Variation in velocity of ink droplets ejected by 10 randomly numbered nozzles with time of driving voltage.（a）Variation in velocity of ink droplets ejected by 10 randomly numbered nozzles with rising time T_R；（b）variation in velocity of ink droplets ejected by 10 randomly numbered nozzles with peak time T_P；（c）variation in velocity of ink droplets ejected by 10 randomly numbered nozzles with falling time T_F

Fig. 5. Volume of ink droplets ejected by 10 randomly numbered nozzles varying with driving high voltage

Fig. 6. Volume of ink droplets ejected by 10 randomly numbered nozzles varying with peak time of driving voltage

Fig. 7. Variation of droplet volume variance with driving voltage for multi-nozzle inkjet printing.（a）Variation of droplet volume variance with driving low voltage for multi-nozzle inkjet printing；（b）variation of droplet volume variance with driving high voltage for multi-nozzle inkjet printing

Fig. 8. Variation of droplet volume variance with time of driving voltage for multi-nozzle inkjet printing and ink droplets ejected simultaneously and uniformly by multi-nozzles after optimizing inkjet printing parameters.（a）Variation of droplet volume variance with T_R for multi-nozzle inkjet printing；（b）variation of droplet volume variance with T_P for multi-nozzle inkjet printing；（c）variation of droplet volume variance with T_F for multi-nozzle inkjet printing；（d）ink droplets ejected simultaneously and uniformly by multi-nozzles after optimizing inkjet printing parameters

Table 1. Minimum variance and range deviation of volume variance of droplets ejected simultaneously by multi-nozzles with different inkjet printing parameters