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Electrode Drive Compensator for Soft Transitions in Electrolyte Printing

IP.com Disclosure Number: IPCOM000044490D
Original Publication Date: 1984-Dec-01
Included in the Prior Art Database: 2005-Feb-06
Document File: 2 page(s) / 40K

Publishing Venue

IBM

Related People

Acciai, MA: AUTHOR [+4]

Abstract

In electrolytic printing technology, the anodes are driven to a plus voltage, nominally 15 volts, during write/print time and to zero or ground level during the non-print or off-time. Because of the nature of the electrode electrolyte system, there is a small capacitance present within the bulk between anode and cathode. Charging and discharging this capacitance results in large positive and negative current spikes at the on/off transitions. Discharge of the galvanic cell created by the bromine and hydrogen generated at the anode and cathode, respectively, during the "on" time may also contribute to the negative spike. The high current densities at the electrode during these spikes, accelerate electrode corrosion.

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Electrode Drive Compensator for Soft Transitions in Electrolyte Printing

In electrolytic printing technology, the anodes are driven to a plus voltage, nominally 15 volts, during write/print time and to zero or ground level during the non-print or off-time. Because of the nature of the electrode electrolyte system, there is a small capacitance present within the bulk between anode and cathode. Charging and discharging this capacitance results in large positive and negative current spikes at the on/off transitions. Discharge of the galvanic cell created by the bromine and hydrogen generated at the anode and cathode, respectively, during the "on" time may also contribute to the negative spike. The high current densities at the electrode during these spikes, accelerate electrode corrosion. The negative spike is especially detrimental in the case of noble metal electrodes, such as platinum, where cycling between anodic and cathodic potentials greatly increases corrosion over what occurs in continuous anodic operation. The compensation network illustrated in Fig. 1 completely eliminates the high positive and negative currents at the transition times. The soft transition is accomplished by the addition of an R-C network in series with the anode. Current comparisons, with and without soft compensation, are depicted respectively in Figs. 2 and 3. The values of R = 200 ohms and C = .1 uf were empirically determined for a write cycle time of 700 microseconds. As a result of...