Liquid Ejecting Head Flexible Substrate Cutout Design
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Solution Overview
Problem
Existing liquid ejecting heads face a trade-off between reducing size and increasing wiring width, as reducing the width of the flexible substrate to fit through a smaller opening portion increases heat generation, while increasing the wiring width to suppress heat generation requires a larger opening portion, thus increasing the head's size.
Innovation Solution
A liquid ejecting head design featuring a flexible substrate with a straight portion and a wider portion, where the straight portion is inserted through a cutout in the case member's side wall, allowing for sufficient wiring width without increasing the opening portion's size, thereby reducing the overall head size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the width of the flexible substrate is reduced to fit through a smaller opening portion, then the size of the liquid ejecting head is reduced, but the wiring width is reduced resulting in more heat generation
Solution Approach 1:
The flexible substrate is divided into two distinct portions: a straight portion for insertion through the opening and a wide portion for electrical connection. This segmentation allows each portion to have optimized dimensions - the straight portion fits through the small opening while the wide portion provides sufficient wiring width to reduce heat generation.
Solution Approach 2:
The flexible substrate extends in the width direction beyond the opening portion through the cutout, utilizing the lateral dimension to provide adequate wiring area without increasing the footprint of the opening portion itself. This dimensional approach resolves the conflict between compact size and heat dissipation requirements.
2Temperature
If the wiring width of the flexible substrate is increased to suppress heat generation, then heat generation is reduced, but the width of the opening portion needs to be increased, resulting in an increased size of the liquid ejecting head
Solution Approach 1:
By segmenting the flexible substrate into straight and wide portions, the wiring can be sufficiently wide for heat suppression without requiring the entire substrate to be wide. The wide portion is positioned such that it does not increase the opening portion dimensions, thus avoiding head size increase.
Solution Approach 2:
The flexible substrate has different widths at different locations - narrow at the insertion point and wide at the wiring area. This local quality variation allows adequate wiring width for heat suppression only where needed, without increasing the overall head 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 effectively reduces the size of the liquid ejecting head while ensuring adequate wiring width to suppress heat generation, allowing for a compact and efficient design.
Implementation Method 1
a pressure of the pressure chamber is changed in accordance with drive of the piezoelectric element
Data Source
AI summary
A liquid ejecting head includes a liquid ejection unit, a flexible substrate, and a case member. The liquid ejection unit includes a drive element, a pressure chamber, and a nozzle. The flexible substrate is electrically connected to the drive element. The case member includes a flow channel configured to supply the liquid to the pressure chamber and an opening portion through which the flexible substrate is inserted. The flexible substrate has a straight portion and a wide portion having a width more than that of the straight portion. The case member has a side wall surrounding the opening portion, and a cutout portion formed in the side wall and configured to release the opening portion outward from the side wall. Portions of the side wall across the cutout portion are positioned outside the straight portion of the flexible substrate disposed in the opening portion.