Liquid Ejecting Head Terminal Alignment for Compact Design
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Solution Overview
Problem
The challenge in liquid ejecting heads, such as ink jet recording heads, is the reliability of terminal connections due to the close arrangement of nozzles and lead wires, which can cause short circuits and connection failures due to expansion of flexible cables made of polyimide materials from heat or moisture, making it difficult to maintain alignment and ensure reliable connections.
Innovation Solution
The design includes a wiring element with flexible insulation and terminals arranged in a specific inclined pattern relative to the center terminals, allowing for alignment adjustments when the wiring member expands, ensuring reliable connections and enabling a reduced size for the liquid ejecting head while maintaining terminal alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If nozzles and lead wires are closely arranged to reduce device size, then productivity and compactness are improved, but reliability deteriorates due to short circuit risks and connection failures
Solution Approach 1:
The patent applies asymmetry by arranging side portion terminals at an inclination angle relative to the longitudinal direction, while center portion terminals remain parallel to the longitudinal direction. This asymmetric configuration creates expansion compensation space that prevents connection failures when the flexible cable expands due to heat or moisture, thereby maintaining reliability while preserving compact device size.
2Ease of manufacture
If flexible cable is used for wiring, then ease of manufacture and adaptability are improved, but reliability deteriorates due to expansion from heat or moisture causing misalignment
Solution Approach 1:
The patent implements preliminary action by pre-configuring the side portion terminals at an inclination angle before the flexible cable expansion occurs. This anticipatory design ensures that when the cable expands due to heat or moisture during operation, the inclined terminals can accommodate the displacement and maintain proper connection alignment, preventing connection failures.
3Volume of moving object
If lead wire width is reduced to enable close arrangement, then device size is reduced, but reliability deteriorates due to increased short circuit risk
Solution Approach 1:
The patent applies segmentation by dividing the terminal arrangement into center portion terminals (parallel to longitudinal direction) and side portion terminals (inclined relative to longitudinal direction). This segmented approach creates functional zones where the inclined side terminals provide expansion compensation space, effectively preventing short circuits between closely arranged narrow lead wires while maintaining compact device size.
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 ensures reliable terminal connections by allowing for alignment adjustments due to expansion, maintaining connection reliability and enabling a compact size for the liquid ejecting head, even when the flexible cable expands, thereby preventing connection failures.
Implementation Method 1
a drive voltage (drive pulse) is applied to the piezoelectric elements so as to vary the volumes of pressure chambers, thereby varying the pressure of a liquid stored in the pressure chambers, allowing the droplets of liquid to be ejected through the nozzles
Implementation Method 2
a flexible cable made of polyimide or the like may expand due to heat or moisture during bonding of wires to the piezoelectric elements. Specifically, the flexible cable expands in the terminal row direction
Data Source
AI summary
A liquid ejecting head that can be of reduced size while maintaining reliability of the terminal connection is provided. According to the liquid ejecting head of the invention, individual element electrode terminals and first side individual electrode wiring terminals of a flexible cable, which are connected to the individual element electrode terminals are arrayed in a direction of a row of pressure chambers, and at least one of a side individual element electrode terminals located in a side portion in a terminal row direction X and a first side individual electrode wiring terminals connected to the side individual element electrode terminals are arranged inclined with respect to a center individual element electrode terminals located in the center portion in the terminal row direction.