Capacitive Crosstalk Voltage Waveform Measurement in Print Heads
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Solution Overview
Problem
Existing electrical circuits in print heads used for measuring voltage amplitude waveforms are hindered by the additional capacitive load of test lines, which impede accurate determination of the waveforms applied to the print head, affecting the jetting performance.
Innovation Solution
An electrical circuit with a conductor in physical proximity to the connecting circuit that utilizes capacitive crosstalk to measure the shape of voltage amplitude waveforms, minimizing the influence of the measurement on the waveform, allowing for accurate determination and monitoring of small changes over the lifetime of the print head.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a test line is used to measure the voltage amplitude waveform, then the waveform can be read externally, but the additional capacitive load changes the waveform and impedes accurate determination
Solution Approach 1:
The patent introduces a coupling circuit as an intermediary between the test line and the voltage amplitude waveform. This coupling circuit transfers the waveform information to the test line through capacitive coupling without requiring direct connection, thereby reducing the additional capacitive load effect on the measured waveform while still enabling external reading of the waveform characteristics.
2Loss of information
If the measurement system is made more invasive to improve measurement capability, then measurement information can be obtained, but the measurement influences and distorts the voltage amplitude waveform
Solution Approach 1:
The patent replaces direct electrical connection (mechanical/electrical contact) with capacitive coupling for waveform measurement. This substitution allows the test line to sense the voltage amplitude waveform through electric field coupling without physical connection, thereby obtaining waveform information while minimizing the disturbance and distortion caused by direct connection.
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
This approach enables more accurate measurement and compensation for deviations in voltage amplitude waveforms, improving the jetting performance and reliability of the print head by reducing the impact of measurement on the waveform, thus enhancing the overall performance throughout its lifetime.
Implementation Method 1
a conductor in physical proximity to the connecting circuit for measuring the shape of the generated voltage amplitude waveform via capacitive crosstalk
Implementation Method 2
an integrated circuit for generating one or more voltage amplitude waveforms to be applied to a piezoelectric actuator present in an ink chamber in a print head. When the designed voltage amplitude waveforms are applied to said piezoelectric actuator, the deformation of the piezoelectric actuator causes the ink in the ink chamber to be jetted
Data Source
AI summary
An electrical circuit for measuring the shape of a voltage waveform in a print head of a printer includes an integrated circuit for generating one or more voltage amplitude waveforms. The electrical circuit includes an inkjet drop forming unit including a plurality of inkjet chambers, wherein each of the plurality of inkjet chambers includes a piezoelectric actuator and an ink nozzle, and a connecting circuit between the integrated circuit and the inkjet drop forming unit suitable for applying one of the one or more voltage amplitude waveforms generated by the integrated circuit to the piezoelectric actuator in one of the plurality of inkjet chambers. In order to measure the shape of the one or more generated voltage amplitude waveforms via capacitive crosstalk, the electrical circuit also includes a conductor in physical proximity to the connecting circuit.