Piezoelectric Vibration Period Adjustment for Ejection Inspection
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Solution Overview
Problem
Liquid ejecting apparatuses face challenges in accurately detecting ejection abnormalities due to manufacturing variations and adhesive extrusion, which affect the vibration period of piezoelectric elements, leading to degraded inspection accuracy.
Innovation Solution
The apparatus includes a mechanism where a second piezoelectric element maintains a deformed state during inspection, adjusting the tensile force on the first vibration portion to match the target vibration period, using a signal generation circuit to apply a constant adjustment voltage and varying voltages to align the vibration period with the reference value, and incorporating a temperature detection mechanism to adjust for temperature-induced variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a piezoelectric element is driven to inspect ejection abnormality based on residual vibration, then ejection inspection can be performed, but manufacturing variations and adhesive extrusion cause the vibration period to differ from the design target value, degrading inspection accuracy
Solution Approach 1:
The patent applies preliminary action by adjusting the vibration period of the piezoelectric element before the actual ejection inspection is performed. The adjustment mechanism pre-corrects for manufacturing variations and adhesive extrusion effects that would otherwise cause the vibration period to deviate from the design target value, ensuring accurate inspection results when the inspection actually occurs.
Solution Approach 2:
The patent implements parameter changes by dynamically adjusting the vibration period parameter of the piezoelectric element. Through the adjustment mechanism, physical parameters such as the stiffness or mass of the vibration system are modified to compensate for manufacturing variations and adhesive extrusion, thereby aligning the actual vibration period with the design target value for accurate ejection inspection.
2Ease of manufacture
If substrates are bonded with adhesive to assemble the liquid ejecting head, then the device can be manufactured, but adhesive extrusion may attach to the flexible plane and alter the vibration period from the design target value
Solution Approach 1:
The patent applies preliminary action by providing an adjustment mechanism that compensates for adhesive extrusion effects after substrate assembly. The mechanism pre-adjusts the vibration period to account for the presence of adhesive on the flexible plane, ensuring that manufacturing simplicity does not compromise vibration period consistency.
Solution Approach 2:
The patent converts the harmful effect of adhesive extrusion into a manageable parameter by providing an adjustment mechanism that specifically compensates for adhesive-induced changes. The mechanism transforms the adverse impact of adhesive presence on vibration period into a correctable deviation, allowing standard assembly processes to continue while maintaining precision.
3Measurement precision
If the vibration period is adjusted to match the design target value, then inspection accuracy is improved, but additional adjustment mechanisms and control circuits are required
Solution Approach 1:
The patent introduces an intermediary adjustment mechanism that mediates between the piezoelectric element and the inspection system. This intermediary component provides a relatively simple interface for vibration period adjustment, avoiding the need for complex control systems while still achieving the goal of matching the design target value for accurate inspection.
Solution Approach 2:
The patent implements parameter changes through a straightforward adjustment mechanism that modifies the vibration period parameter. By focusing on changing only the necessary physical parameters (such as stiffness or mass) rather than implementing complex control algorithms, the patent achieves improved inspection accuracy with minimal increase in device complexity.
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 configuration enhances the detection accuracy of ejection abnormalities by aligning the vibration period with the design target, improving the reliability of inspecting liquid ejection from nozzles and maintaining the integrity of the inspection process.
Implementation Method 1
a piezoelectric element provided corresponding to and opposite to the hollow portion with the flexible plane in between... vibration generated when the piezoelectric element is driven
Implementation Method 2
an electromotive force of the piezoelectric element caused by vibration generated when the piezoelectric element is driven
Data Source
AI summary
A liquid ejecting apparatus includes a liquid ejecting head including a substrate where a plurality of hollow portions are formed, a flexible plane that delimits a part of the hollow portion, and a piezoelectric element provided corresponding to the hollow portion, an inspection mechanism that inspects ejection of liquid from a nozzle based on an electromotive force of the piezoelectric element, and a signal generation circuit that generates a first drive signal and a second drive signal. The second drive signal maintains a state, where a second vibration portion including the second piezoelectric element and the flexible plane corresponding to the second piezoelectric element is deformed, during a detection period in which the inspection mechanism performs inspection based on vibration caused when a first vibration portion including the first piezoelectric element and the flexible plane corresponding to the first piezoelectric element is driven.