Electrostatic Deflection Printer Monitoring Before Arc Shutdown
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Solution Overview
Problem
Electrostatic deflection continuous ink jet printers are prone to unexpected shutdowns due to dielectric breakdowns and electrical arcing at deflection electrodes, which can disrupt industrial printing operations and require costly unplanned line stoppages.
Innovation Solution
A monitoring system that detects current levels and transients at deflection electrodes, providing advance warnings when current exceeds normal levels for a clean print head but is below the threshold for automatic shutdown, allowing for planned maintenance to prevent unexpected shutdowns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the printer automatically shuts down when current exceeds a threshold to prevent damage, then reliability is improved, but productivity deteriorates due to unexpected shutdowns disrupting continuous printing operations
Solution Approach 1:
The monitoring system performs preliminary detection of current levels and transients at deflection electrodes before they reach dangerous thresholds. By identifying early signs of dielectric breakdown and electrical arcing, the system enables planned maintenance interventions that prevent unexpected shutdowns, thus maintaining both reliability and productivity.
Solution Approach 2:
The system continuously monitors current parameters at deflection electrodes and provides feedback about the electrical condition of the print head. This feedback mechanism allows operators to assess the health status of the printer and schedule maintenance proactively, avoiding both premature shutdowns and operation during deteriorating conditions.
2Productivity
If the printer operates with contaminated deflection electrodes to maintain productivity, then productivity is improved, but reliability deteriorates due to increased risk of dielectric breakdown and electrical arcing
Solution Approach 1:
The monitoring system detects early signs of contamination effects such as increased current transients and dielectric breakdown before they cause catastrophic failure. This preliminary detection allows operators to clean deflection electrodes during planned maintenance windows, ensuring both continuous productivity and reliable operation.
3Reliability
If the printer shuts down immediately when current exceeds threshold to ensure safety, then reliability is improved, but loss of time increases due to unplanned line stoppages
Solution Approach 1:
The system performs preliminary monitoring and detection of current anomalies that indicate developing electrical problems. By identifying issues before they reach critical thresholds, the system enables scheduled maintenance during non-critical periods, avoiding both safety risks and unplanned production losses.
Solution Approach 2:
The monitoring system provides self-diagnostic capability by continuously assessing the electrical condition of deflection electrodes. This self-service monitoring empowers operators to make informed decisions about maintenance timing, balancing safety requirements with production needs without external intervention.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables operators to schedule maintenance to avoid disruptive printer shutdowns, reducing downtime and maintaining continuous printing operations.
Implementation Method 1
The print head comprises an arrangement of electrodes to trap electric charges on some or all of the ink drops and to create an electrostatic field to deflect the charged drops
Implementation Method 2
the drops will be charged by the influence of a voltage on the charge electrode
Implementation Method 3
The charged drops will usually be deflected by the electrostatic field generated by a pair of deflection electrodes
Implementation Method 4
monitoring the electric supply to the deflection electrodes, e.g. by monitoring the supplied current or voltage
Implementation Method 5
If there is a dielectric breakdown in the air gap between the gutter and one of the deflection electrodes, this can result in an arc current flowing at the deflection electrode
Data Source
Figure 1~3
Figure 4
Figure 5
AI summary
The current at a deflection electrode 23, 25 of an electrostatic deflection continuous inkjet printer 127 is monitored. If the current reaches a level higher than normal for a clean print head but below the current required to trigger an automatic shutdown, a warning is generated. The warning indicates that an automatic shutdown is likely to follow unless the print head is cleaned. This allows the operator to shut the printer down in a planned manner for cleaning. The warning may be provided at the printer 127 or it may be provided by an external system 121, 129 which allows personnel who are not at the printer to be alerted. The monitoring may be done by the printer or information about the deflection electrode current may be provided to an external system 121, 129 that performs the monitoring.