Nozzle Inspection Signal Differencing for Noise-Resistant Ejection
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Solution Overview
Problem
Existing liquid ejection apparatuses face difficulties in accurately determining whether a nozzle is abnormal due to noise interference from the AC power source, making it challenging to perform ejection inspections effectively.
Innovation Solution
A liquid ejection apparatus that includes a liquid ejection head, a signal output device, and a controller, which generates a differential signal by superposing a determination signal and a non-driving signal to reduce noise components and accurately determine nozzle abnormalities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If noise inspection is performed to determine the presence or absence of noise, then the accuracy of nozzle abnormality determination should be improved, but it becomes difficult to actually perform ejection inspection in a state where there is no noise since a certain amount of noise is always input from an AC power source
Solution Approach 1:
The patent converts the harmful noise component into a beneficial element by using it as a reference for differential comparison. The noise inspection result is not used to reject measurements, but rather to establish a baseline that helps identify abnormal nozzles through differential signal processing, transforming the unavoidable noise into a useful reference for accurate determination
Solution Approach 2:
The patent changes the evaluation parameter from absolute signal threshold judgment to differential signal comparison. Instead of determining nozzle abnormalities based on fixed thresholds that are affected by noise levels, the system calculates the difference between inspection signals and reference signals, making the determination robust against constant noise components from the AC power source
2Ease of operation
If ejection inspection is performed using fixed threshold values, then the inspection process is simple, but the determination accuracy deteriorates when noise is present in the detection signal
Solution Approach 1:
The patent performs preliminary noise inspection and reference signal acquisition before the actual ejection inspection. By pre-characterizing the noise environment and storing reference signals, the system prepares the necessary data for differential comparison, maintaining operational simplicity while enabling accurate noise-resistant determination during the actual inspection
Solution Approach 2:
The patent introduces differential signal processing as an intermediary step between raw signal acquisition and final determination. This intermediary process subtracts the reference signal (containing noise) from the inspection signal, eliminating the need for complex noise filtering while preserving the simplicity of the overall inspection workflow
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
The differential signal effectively reduces noise interference, allowing for precise identification of abnormal nozzles by minimizing noise influence and ensuring accurate ejection inspection results.
Implementation Method 1
a piezo element of a head
Data Source
AI summary
A liquid ejection head has a nozzle. A controller is configured to: control the liquid ejection head to perform inspection driving, the inspection driving being driving the liquid ejection head to eject liquid from the nozzle for determining whether the nozzle is an abnormal nozzle having an abnormality in ejection of liquid; acquire a determination signal outputted from the signal output device, the determination signal indicating whether the nozzle is the abnormal nozzle; acquire a non-driving signal outputted from the signal output device when the inspection driving is not performed by the liquid ejection head; generate a differential signal by superposing the determination signal and the non-driving signal, the differential signal being a signal indicating a difference between a value of the determination signal and a value of the non-driving signal at each timing; and determine whether the nozzle is the abnormal nozzle based on the differential signal.