Liquid Droplet Ejection Detection via Dual-Distance Measurements
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Solution Overview
Problem
Conventional methods struggle to detect nozzle ejection failures in liquid droplet ejecting apparatuses with high precision, leading to potential erroneous determinations.
Innovation Solution
A liquid droplet ejecting apparatus with a metal ejecting head, an electrode, a voltage source, and an electric current detector, which calculates droplet flying speed and ejection bending amount based on distance and time, allowing precise detection of ejection failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If only flying speed is measured to detect ejection failure, then the detection method is simple, but the detection precision is insufficient leading to erroneous determinations
Solution Approach 1:
The detection process is segmented into two distinct measurement phases: first measuring flying speed at a shorter distance (first distance), then measuring ejection bending amount at a longer distance (second distance). This segmentation allows each measurement to target specific characteristics, with the bending amount measurement specifically capturing directional deviations that speed alone cannot detect, thereby resolving the contradiction between simplicity and precision.
Solution Approach 2:
The invention transitions from one-dimensional speed measurement to two-dimensional characterization by adding the ejection bending amount (directional component) to the flying speed (magnitude component). This dimensional expansion enables comprehensive detection of ejection failures, capturing both speed anomalies and directional deviations, thus achieving high precision without excessive complexity.
2Loss of time
If the electrode is positioned closer to the ejection surface (first distance), then the detection time is short, but the ejection bending amount is too small to detect with high precision
Solution Approach 1:
The system performs a preliminary measurement at the first distance to capture flying speed, then proceeds to a second measurement at the second distance to capture ejection bending amount. This preliminary action sequence ensures that the critical bending amount measurement is performed under optimal conditions (greater distance) without compromising the overall detection efficiency, as the speed measurement is already completed in the first phase.
Solution Approach 2:
The electrode position is made dynamic rather than fixed, allowing it to be adjusted between two distinct positions (first distance and second distance) depending on the measurement objective. This dynamic positioning enables the system to optimize for either speed measurement (closer position) or bending amount measurement (farther position), resolving the contradiction between detection time and measurement precision.
3Measurement precision
If the electrode is positioned farther from the ejection surface (second distance), then the ejection bending amount is larger and more detectable, but the detection time increases
Solution Approach 1:
The detection process employs periodic action by alternating between two measurement cycles: one cycle uses the first distance for speed measurement, and another cycle uses the second distance for bending amount measurement. This periodic switching allows the system to achieve high precision bending detection when needed while maintaining overall detection efficiency through the faster first-distance measurements performed in alternating cycles.
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 precise detection of ejection failures by calculating droplet speed and bending amount, reducing noise influence and improving detection accuracy.
Implementation Method 1
a voltage source configured to generate a potential difference between the ejecting head and the electrode
Implementation Method 2
a voltage source configured to generate a potential difference between the ejecting head and the electrode; an electric current detector configured to detect an electric current flowing between the ejecting head and the electrode
Implementation Method 3
an electric current detector configured to detect an electric current flowing between the ejecting head and the electrode
Data Source
AI summary
A liquid droplet ejecting apparatus includes: an ejecting head made of metal and having an ejection surface; an electrode which moves relative to the ejection surface; a voltage source generating a potential difference between the ejecting head and the electrode; an electric current detector detecting an electric current between the ejecting head and the electrode; and a controller. The controller is configured to: calculate a flying speed of the liquid droplet based on a first distance between the ejecting head and the electrode and a time during which the electric current flows between the ejecting head and the electrode; and calculate an ejection bending amount, based on a time after the liquid droplet is ejected from the ejecting head in a state that the ejection surface and the electrode are apart from each other by a second distance and until the liquid droplet lands on the electrode.