Liquid Discharging Head Circulation Flow Path Design
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Solution Overview
Problem
The existing liquid discharging heads face a challenge with the photosensitive resin layer being exposed to the circulation flow path, leading to swelling or reaction with ink, which reduces the strength of the head due to contact, especially when the circulation flow path penetrates through both the flow path forming substrates and the resin layer.
Innovation Solution
The design includes a configuration where the first and second flow path members are stacked with a wiring substrate in between, forming distinct regions, and the circulation flow path is created by communicating flow paths within these members, avoiding direct exposure of the adhesive layer to the ink, thus maintaining mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the circulation flow path is formed to penetrate the flow path member and wiring substrate, then the liquid can circulate through the pressure chamber, but the photosensitive resin layer is exposed to the liquid causing swelling or reaction that lowers the strength
Solution Approach 1:
The flow path member is divided into a first flow path member and a second flow path member stacked in the first direction. The circulation flow path is formed by communicating flow paths in these separate members through the second region, rather than penetrating through a single layered structure. This segmentation prevents the adhesive layer from being exposed to the circulating liquid.
Solution Approach 2:
The surface of the first flow path member is divided into a first region (stacked on the second flow path member via the wiring substrate) and a second region (stacked on the second flow path member without the wiring substrate). The circulation flow path is specifically formed in the second region where the adhesive layer is not present, creating a localized solution that maintains strength while enabling circulation.
2Ease of manufacture
If the photosensitive resin layer is used as an adhesive layer to join the flow path member and wiring substrate, then the components can be connected, but the resin layer reacts with the ink in the circulation flow path causing swelling and strength reduction
Solution Approach 1:
The adhesive layer (photosensitive resin layer) is extracted from the circulation flow path by positioning it only in the first region, while the circulation flow path is formed exclusively in the second region. This separation removes the harmful interaction between the adhesive layer and the circulating liquid, allowing the adhesive to maintain its strength.
Solution Approach 2:
The wiring substrate acts as an intermediary element that enables the circulation flow path to be formed without requiring the adhesive layer to be exposed to the liquid. The circulation path communicates between the first and second flow path members through the region where the wiring substrate is present, bypassing the need for adhesive exposure.
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 prevents the photosensitive resin layer from being exposed to the ink, enhancing the mechanical strength of the liquid discharging head by avoiding contact and maintaining the adhesive layer's integrity.
Implementation Method 1
a piezoelectric element for generating a pressure change in the pressure chamber
Implementation Method 2
the photosensitive resin layer swells or reacts due to contact between the liquid and the photosensitive resin layer
Data Source
AI summary
A liquid discharging head includes a first flow path member comprising a first flow path and a pressure chamber; a second flow path member stacked on the first flow path member and comprising a second flow path; a wiring substrate comprising a connection terminal for electrically connected to a driving element to generate a pressure change in the pressure chamber; and a circulation flow path for circulating the liquid through the pressure chamber. A surface of the first flow path member includes a first region which is stacked on the second flow path member via the wiring substrate and a second region which is stacked on the second flow path member without the wiring substrate. The first flow path and the second flow path are in communication with each other in the second region so as to be the circulation flow path.