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Title: Charging of moving surfaces by corona discharges sustained in air

Abstract

Atmospheric pressure corona discharges are used in electrophotographic (EP) printing technologies for charging imaging surfaces such as photoconductors. A typical corona discharge consists of a wire (or wire array) biased with a few hundred volts of dc plus a few kV of ac voltage. An electric discharge is produced around the corona wire from which electrons drift towards and charge the underlying dielectric surface. The surface charging reduces the voltage drop across the gap between the corona wire and the dielectric surface, which then terminates the discharge, as in a dielectric barrier discharge. In printing applications, this underlying surface is continuously moving throughout the charging process. For example, previously charged surfaces, which had reduced the local electric field and terminated the local discharge, are translated out of the field of view and are replaced with uncharged surface. The uncharged surface produces a rebound in the electric field in the vicinity of the corona wire which in turn results in re-ignition of the discharge. The discharge, so reignited, is then asymmetric. We found that in the idealized corona charging system we investigated, a negatively dc biased corona blade with a dielectric covered ground electrode, the discharge is initially sustained by electronmore » impact ionization from the bulk plasma and then dominated by ionization from sheath accelerated secondary electrons. Depending on the speed of the underlying surface, the periodic re-ignition of the discharge can produce an oscillatory charging pattern on the moving surface.« less

Authors:
;  [1];  [2]; ; ;  [3]
  1. Department of Electrical Engineering and Computer Science, University of Michigan, 1301 Beal Ave., Ann Arbor, Michigan 48109-2122 (United States)
  2. Tianjin University, Tianjin (China)
  3. Hewlett-Packard Research Labs, Palo Alto, California 94304 (United States)
Publication Date:
OSTI Identifier:
22308921
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 116; Journal Issue: 4; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; AIR; ASYMMETRY; ATMOSPHERIC PRESSURE; CORONA DISCHARGES; DIELECTRIC MATERIALS; ELECTRIC FIELDS; ELECTRIC POTENTIAL; ELECTRODES; ELECTRON DRIFT; IONIZATION; PERIODICITY; PHOTOCONDUCTORS; PLASMA; SURFACES; VOLTAGE DROP

Citation Formats

Wang, Jun-Chieh, E-mail: junchwan@umich.edu, Kushner, Mark J., E-mail: mjkush@umich.edu, Zhang, Daihua, E-mail: dhzhang@tju.edu.cn, Leoni, Napoleon, E-mail: napoleon.j.leoni@hp.com, Birecki, Henryk, E-mail: henryk.birecki@hp.com, and Gila, Omer, E-mail: omer-gila@hp.com. Charging of moving surfaces by corona discharges sustained in air. United States: N. p., 2014. Web. doi:10.1063/1.4890520.
Wang, Jun-Chieh, E-mail: junchwan@umich.edu, Kushner, Mark J., E-mail: mjkush@umich.edu, Zhang, Daihua, E-mail: dhzhang@tju.edu.cn, Leoni, Napoleon, E-mail: napoleon.j.leoni@hp.com, Birecki, Henryk, E-mail: henryk.birecki@hp.com, & Gila, Omer, E-mail: omer-gila@hp.com. Charging of moving surfaces by corona discharges sustained in air. United States. doi:10.1063/1.4890520.
Wang, Jun-Chieh, E-mail: junchwan@umich.edu, Kushner, Mark J., E-mail: mjkush@umich.edu, Zhang, Daihua, E-mail: dhzhang@tju.edu.cn, Leoni, Napoleon, E-mail: napoleon.j.leoni@hp.com, Birecki, Henryk, E-mail: henryk.birecki@hp.com, and Gila, Omer, E-mail: omer-gila@hp.com. Mon . "Charging of moving surfaces by corona discharges sustained in air". United States. doi:10.1063/1.4890520.
@article{osti_22308921,
title = {Charging of moving surfaces by corona discharges sustained in air},
author = {Wang, Jun-Chieh, E-mail: junchwan@umich.edu and Kushner, Mark J., E-mail: mjkush@umich.edu and Zhang, Daihua, E-mail: dhzhang@tju.edu.cn and Leoni, Napoleon, E-mail: napoleon.j.leoni@hp.com and Birecki, Henryk, E-mail: henryk.birecki@hp.com and Gila, Omer, E-mail: omer-gila@hp.com},
abstractNote = {Atmospheric pressure corona discharges are used in electrophotographic (EP) printing technologies for charging imaging surfaces such as photoconductors. A typical corona discharge consists of a wire (or wire array) biased with a few hundred volts of dc plus a few kV of ac voltage. An electric discharge is produced around the corona wire from which electrons drift towards and charge the underlying dielectric surface. The surface charging reduces the voltage drop across the gap between the corona wire and the dielectric surface, which then terminates the discharge, as in a dielectric barrier discharge. In printing applications, this underlying surface is continuously moving throughout the charging process. For example, previously charged surfaces, which had reduced the local electric field and terminated the local discharge, are translated out of the field of view and are replaced with uncharged surface. The uncharged surface produces a rebound in the electric field in the vicinity of the corona wire which in turn results in re-ignition of the discharge. The discharge, so reignited, is then asymmetric. We found that in the idealized corona charging system we investigated, a negatively dc biased corona blade with a dielectric covered ground electrode, the discharge is initially sustained by electron impact ionization from the bulk plasma and then dominated by ionization from sheath accelerated secondary electrons. Depending on the speed of the underlying surface, the periodic re-ignition of the discharge can produce an oscillatory charging pattern on the moving surface.},
doi = {10.1063/1.4890520},
journal = {Journal of Applied Physics},
number = 4,
volume = 116,
place = {United States},
year = {Mon Jul 28 00:00:00 EDT 2014},
month = {Mon Jul 28 00:00:00 EDT 2014}
}
  • Successful introduction of pulsed corona for industrial purposes very much depends on the reliability of high-voltage and pulsed power technology and on the efficiency of energy transfer. In addition, it is of the utmost importance that adequate electromagnetic compatibility (EMC) is achieved between the high-voltage pulse source and the surrounding equipment. Pulsed corona is generated in a pilot unit that produces narrow 50 MW pulses at 1000 pps (net average corona power 1.5 kW). The pilot unit can run continuously for use in industrial applications such as cleaning of gases (100 m{sup 3}/h) containing NO or volatile organic compounds (VOC`s)more » or fluids (e.g., waste water). Simultaneous removal of NO and ethylene to obtain clean CO{sub 2} from the exhaust of a combustion engine was tested at an industrial site. Various chemical processes, such as removal of toluene or styrene from an airflow are tested in the laboratory. The authors developed a model to analyze the conversion of these pollutants. To examine the discharges in the reactor they use current, voltage, and E-field sensors as well as a fast charge-coupled device (CCD) camera. Detailed energy input measurements are compared with CCD movies to investigate the efficiency of different streamer phases. EMC techniques incorporated in the pilot unit are based on the successful concept of constructing a low transfer impedance between common mode currents induced by pulsed power and differential mode voltages in signal lines and external main lines.« less
  • A point-plane electrode system in atmospheric air is established to investigate the mechanism of the corona discharge. By using this system, the current pulses of the corona discharges under the 50 Hz ac voltage are measured using partial discharge (PD) measurement instrument and constitute the point-plane voltage-current (V-I) characteristic equation together with the voltage. Then, this paper constructs the nonlinear circuit model and differential equations of the system in an attempt to give the underlying dynamic mechanism based on the nonlinear V-I characteristics of the point-plane corona discharges. The results show that the chaotic phenomenon is found in the coronamore » circuit by the experimental study and nonlinear dynamic analysis. The basic dynamic characteristics, including the Lyapunov exponent, the existence of the strange attractors, and the equilibrium points, are also found and analyzed in the development process of the corona circuit. Moreover, the time series of the corona current pulses obtained in the experiment is used to demonstrate the chaotic characteristics of the corona current based on the nonlinear dynamic circuit theory and the experimental basis. It is pointed out that the corona phenomenon is not a purely stochastic phenomenon but a short term deterministic chaotic activity.« less
  • This paper presents a numerical model for the inception of positive dc corona discharges in air near cylindrical anodes, which plays a bridge role between the classic positive corona onset criterion and the photoionization model considering the effective radiation wavelength. The predicted onset voltages agree well with Peek's experimental data in a wide range of conductor radii and relative air densities. The influence of the collisional quenching of emitting excited states on the surface onset field is significant with low air density or small conductor radius. Within the effective radiation wavelength, numerical expressions for the photon absorption coefficient in airmore » and Townsend's second coefficient due to photoionization are deduced on the basis of the new model. A different perspective on the classic coefficients is given.« less
  • An analytical study was made in this paper for calculating the ozone generation by negative dc corona discharges. The corona discharges were formed in a coaxial wire-cylinder reactor. The reactor was fed by dry air flowing with constant rates at atmospheric pressure and room temperature, and stressed by a negative dc voltage. The current-voltage characteristics of the negative dc corona discharges formed inside the reactor were measured in parallel with concentration of the generated ozone under different operating conditions. An empirical equation was derived from the experimental results for calculating the ozone concentration generated inside the reactor. The results, thatmore » have been recalculated by using the derived equation, have agreed with the experimental results over the whole range of the investigated parameters, except in the saturation range for the ozone concentration. Therefore, the derived equation represents a suitable criterion for expecting the ozone concentration generated by negative dc corona discharges in dry air fed coaxial wire-cylinder reactors under any operating conditions in range of the investigated parameters.« less
  • This paper presents the experimental measurement and numerical analysis of the current-voltage characteristics of dc corona discharges in air between coaxial cylinders. The current-voltage characteristics for both positive and negative corona discharges were measured within a specially designed corona cage. Then the measured results were fitted by different empirical formulae and analyzed by the fluid model. The current-voltage characteristics between coaxial cylinders can be expressed as I = C(U − U{sub 0}){sup m}, where m is within the range 1.5–2.0, which is similar to the point-plane electrode system. The ionization region has no significant effect on the current-voltage characteristic under a low corona current,more » while it will affect the distribution for the negative corona under a high corona current. The surface onset fields and ion mobilities were emphatically discussed.« less