Analysis of Electrostatic Ejection of Liquid Droplets in Manner of Drop-on-demand Using High-speed Camera

고속카메라를 이용한 Drop-on-demand 방식의 정전 액적 토출 분석

  • 김용재 (성균관대학교 기계공학부 대학원) ;
  • 최재용 (성균관대학교 정보통신공학부) ;
  • 손상욱 (성균관대학교 정보통신공학부) ;
  • 김영민 (성균관대학교 정보통신공학부) ;
  • 이석한 (성균관대학교 정보통신공학부) ;
  • 변도영 (건국대학교 항공우주공학부) ;
  • 고한서 (성균관대학교 기계공학부)
  • Published : 2007.11.30


An electrostatic inkjet head can be used for manufacturing processes of large display systems and printed circuit boards (PCB) as well as inkjet printers because an electrostatic field provides an external force which can be manipulated to control sizes of droplets. The existing printing methods such as thermal bubble and piezo inkjet heads have shown difficulties to control the ejection of the droplets for printing applications. Thus, the new inkjet head has been proposed using the electrostatic force. A numerical analysis has been performed to calculate the intensity of the electrostatic field using the Maxwell's equation. Also, experiments have been carried out to investigate the droplet movement using a downward capillary with outside diameter of $500{\mu}m$. Gravity, surface tension, and electrostatic force have been analyzed with high voltages for a drop-on-demand ejection. It has been observed that the droplet size decreases and the frequency of the droplet formation and the velocity of the droplet ejection increase with increasing the intensity of the electrostatic field using high-speed camera.