A study of ejection modes for pulsed-DC electrohydrodynamic inkjet printing

M. W. Lee, D. K. Kang, N. Y. Kim, H. Y. Kim, S. C. James, S. S. Yoon

Research output: Contribution to journalArticlepeer-review

69 Citations (Scopus)


For electrohydrodynamic-driven drop-on-demand printing techniques, either continuous- or pulsed-DC voltages can generate drops. To generate uniform micro-drops for high-resolution printing, the pulsed-DC voltage method is superior to continuous-DC voltage methods because of its controllability. Voltage amplitude and duration (or duty cycle or relaxation time, τ) are the primary parameters affecting the performance of drop-generation or ejection. When charge accumulates on the fluid meniscus at the nozzle, a drop is ejected. Charge density is the product of voltage (amplitude) and duration. In theory, charge densities from low-amplitude, long-duration voltages are equivalent to those of large amplitude and short duration. However, we demonstrate that drop-ejection mode differs significantly, despite equivalent products when voltage amplitude and duration change. At various voltage amplitudes and durations, four ejection main modes are identified: microdripping, spindle, string-jet, and spray modes. Longer voltage durations yield excessively large, spindle, string-jet, and spray modes. Conversely, no ejection is observed for short voltage durations. The microdripping mode, most desirable for uniform and high-resolution printing, appears for the narrowed range of duration under given pulsed-voltage. The identification map has been constructed for these modes; this map can be used as a guideline to yield a stable microdripping mode for high quality printing.

Original languageEnglish
Pages (from-to)1-6
Number of pages6
JournalJournal of Aerosol Science
Publication statusPublished - 2012 Apr

Bibliographical note

Funding Information:
This work was supported by the Center for Inorganic Photovoltaic Materials NRF-2011-0007182 and 2010-0010217 funded by the Korean government (MEST) . This research was also supported by the Converging Research Center Program through the Ministry of Education Science and Technology ( 2010K000969 ). This work was also supported by the Human Resources Development of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant funded by the Ministry of Knowledge Economy, Republic of Korea (No. 20104010100640 ).


  • Drop-on-demand (DOD)
  • Electrohydrodynamic (EHD)
  • Microdripping mode
  • Pulsed DC

ASJC Scopus subject areas

  • Environmental Engineering
  • Pollution
  • Mechanical Engineering
  • Fluid Flow and Transfer Processes
  • Atmospheric Science


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