Liquid Ejecting Head Wiring Orientation for Nozzle Integrity
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Solution Overview
Problem
Liquid ejecting heads with piezoelectric elements face issues of warping and cracking in the nozzle channel walls due to downward loads applied during the coupling of COF substrates, which can lead to channel deformation and disruption of liquid flow.
Innovation Solution
The design includes a wiring substrate configuration where the wiring sections extending to the piezoelectric elements are positioned to overlap the nozzle channel and extend in a direction different from the nozzle channel's orientation, reducing the likelihood of warping and cracking by distributing loads more evenly and allowing for uniform ink ejection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If COF substrates are coupled to supply driving signals to piezoelectric elements, then the liquid ejecting head can operate, but the downward load causes warping and cracking of the nozzle channel wall
Solution Approach 1:
The patent changes the orientation of the wiring section from extending in the first direction (parallel to nozzle channel) to extending in a third direction orthogonal to the first direction. This dimensional change allows the wiring substrate to be coupled without applying downward load on the nozzle channel wall, thus preventing warping and cracking while maintaining electrical connectivity to the piezoelectric elements
2Reliability
If lead electrodes extend from one row to the other row of piezoelectric elements, then electrical connection is achieved, but the channel wall below the COF substrate coupling position is subjected to great downward load
Solution Approach 1:
The wiring section is reoriented to extend in the third direction (orthogonal to the first direction) instead of extending in the first direction from one row to another. This dimensional reconfiguration maintains electrical connectivity between the COF substrate and piezoelectric elements while eliminating the downward load on the channel wall by changing the coupling geometry
3Productivity
If the wiring substrate is positioned to couple COF substrates, then driving signals can be supplied, but warping and cracking may occur in the nozzle channel
Solution Approach 1:
By changing the wiring section orientation from the first direction to the third direction, the patent enables COF substrate coupling without compromising nozzle channel dimensional stability. The orthogonal arrangement allows signal supply functionality while preventing manufacturing defects such as warping and cracking
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 effectively suppresses warping and cracking in the nozzle channel walls, ensuring stable ink flow and consistent ejection performance by distributing loads and maintaining the structural integrity of the nozzle channel.
Implementation Method 1
a first energy-generating element that generates energy for applying pressure to a liquid in the first pressure chamber
Data Source
AI summary
A liquid ejecting head includes: a pressure chamber; a piezoelectric element that generates energy for applying pressure to an ink in the pressure chamber; a nozzle channel that extends in the X-axis direction and communicates with a nozzle for ejecting the ink; a supply communication channel which enables the pressure chamber and the nozzle channel to communicate with each other; a discharge communication channel which communicates with the nozzle channel; a wiring substrate electrically coupled to a drive circuit that drives the piezoelectric element; and a wiring section that electrically couples the wiring substrate and the piezoelectric element, in which, as viewed in the Z-axis direction orthogonal to the X-axis direction, the wiring section is provided at a position at which the wiring section overlaps the nozzle channel, and the wiring section extends in the ±Q direction, which differs from the X-axis direction.