Liquid Ejection Head Short Circuit Detection via Dual Voltage
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Solution Overview
Problem
Existing liquid ejection devices struggle to detect short circuits between ejection elements, which can lead to improper operation and potential damage, as current methods are inadequate for determining if a short circuit has occurred post-mounting or during ejection head usage.
Innovation Solution
A liquid ejection device with a driving voltage generation unit that supplies distinct driving voltages to ejection elements to differentiate between normal and short-circuited conditions, allowing for the detection of short circuits based on ejection occurrence, utilizing a combination of first and second driving voltages applied to determine if a short circuit exists between ejection elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If electrical measurement methods (capacitance measurement or leakage current measurement) are used to detect short circuits, then detection capability is provided, but the method cannot determine whether a short circuit has occurred after mounting or during usage
Solution Approach 1:
The patent applies preliminary action by performing short circuit detection through ejection status observation before the liquid ejection head is mounted or during usage. The control unit detects short circuits by applying driving voltages and observing ejection statuses in advance, rather than relying on post-mounting electrical measurements that cannot detect short circuits occurring after mounting.
2Measurement precision
If optical microscope or infrared image observation is used to detect short circuits, then visualization of wiring is achieved, but the method is complex and cannot detect short circuits during operation
Solution Approach 1:
The patent replaces complex optical measurement systems (microscope, infrared imaging) with a simple electrical detection system. The control unit applies driving voltages to ejection elements and observes ejection statuses to detect short circuits, substituting mechanical/optical inspection with electrical control and status observation.
3Measurement precision
If a detection electrode portion is added to detect short circuits, then detection function is provided, but the liquid ejection head structure becomes more complex
Solution Approach 1:
The patent applies universality by making the existing ejection elements serve dual functions: both liquid ejection and short circuit detection. The ejection elements are used to eject liquid during normal operation and to detect short circuits by observing their ejection status when driving voltages are applied, eliminating the need for separate detection electrodes.
4Reliability
If continuous monitoring of all ejection elements is performed, then comprehensive short circuit detection is achieved, but energy consumption and operation time increase
Solution Approach 1:
The patent applies partial action by detecting short circuits in only one ejection element at a time through sequential detection. The control unit detects short circuits by applying driving voltages to ejection elements one by one and observing their ejection statuses, rather than monitoring all ejection elements simultaneously, thereby reducing energy consumption and operation time.
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 effective detection of short circuits between ejection elements, preventing damage and ensuring continuous operation by determining if a short circuit has occurred, thereby allowing for timely maintenance or replacement of affected components.
Implementation Method 1
a plurality of ejection elements (68) arranged in a matrix pattern in the longitudinal direction and in the lateral direction. The ejection elements (68) each include a nozzle opening (80), a pressure chamber (84), a diaphragm (86), and a piezoelectric element (98).
Data Source
AI summary
A liquid ejection device includes a head driving unit that generates a first driving voltage and a second driving voltage in which whether or not there is ejection of liquid from a first ejection element in a case where the first driving voltage alone is applied to the first ejection element that is a detection target of a short circuit between ejection elements is different from whether or not there is ejection of liquid from the first ejection element in a case where the first driving voltage and the second driving voltage are applied to the first ejection element, supplies the first driving voltage to the first ejection element, and supplies the second driving voltage to the second ejection element suspected of a short circuit with the first ejection element.