Liquid Ejection Head Wiring Pressing Structure for Heat Dissipation
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Solution Overview
Problem
Existing liquid ejection heads accumulate heat in the actuator member, which affects ejection performance by transmitting heat to the channel member and liquid, and existing solutions risk separating the wiring member from the actuator while applying load to the bonding portion.
Innovation Solution
A liquid ejection head design featuring a pressing member that presses the outer peripheral region of the wiring member onto the actuator without contacting the bonding portion, combined with a thermal interface material of lower hardness to release heat without applying load to the contacts, and a heat dissipation system using water cooling pipes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pressing member presses the connection portion to prevent wiring member separation, then the wiring member remains connected to the actuator member, but heat accumulates in the recessed portion and transmits to the channel member and liquid
Solution Approach 1:
The pressing member is divided into two functional regions: a pressing portion that contacts the outer peripheral portion of the connection portion to prevent separation, and a recessed portion that faces the central portion with a gap, preventing heat accumulation in the contact area. This segmentation allows the pressing member to fulfill both connection reliability and heat dissipation functions simultaneously.
Solution Approach 2:
A thermal interface material is introduced as an intermediary between the actuator member and the pressing member in the central region. This material facilitates heat transfer from the actuator member while the pressing member maintains mechanical connection through its outer peripheral pressing portion, thus resolving the contradiction between connection reliability and heat dissipation.
2Reliability
If the pressing member applies force to the connection portion, then the wiring member is prevented from separating, but the bonding portion of the contact experiences load
Solution Approach 1:
The pressing member is designed with non-uniform contact characteristics: the outer peripheral portion contacts the connection portion to provide pressing force for connection stability, while the central recessed portion creates a gap that prevents load transmission to the bonding portion. This local quality differentiation allows the pressing member to maintain connection stability without compromising bonding portion strength.
3Temperature
If the thermal interface material has low hardness to release heat, then heat dissipation is improved, but the material may deform under pressure
Solution Approach 1:
The thermal interface material is positioned specifically in the central region where heat dissipation is needed, while the outer peripheral region maintains structural integrity through the pressing member's rigid pressing portion. This local placement allows the low-hardness thermal interface material to facilitate heat dissipation without being subject to the full pressing force that would cause deformation.
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
The design effectively suppresses separation of the wiring member from the actuator while efficiently dissipating heat, maintaining ejection performance and preventing load on the bonding portion.
Implementation Method 1
the thermal interface material contacts the second contact region without contacting the second outer peripheral region. The thermal interface material has a lower hardness than the pressing member. Thus, the thermal interface material does not apply a load to the second contact region
Implementation Method 2
The pressing member contacts the second outer peripheral region without contacting the second contact region. Thus, the pressing member does not apply a load to the second contact region. The pressing member is configured to press the second outer peripheral region toward the actuator member
Data Source
AI summary
An actuator member has an upper surface including a first contact region in which a first contact is disposed and a first outer peripheral region surrounding the first contact region. A wiring member includes a connection portion including a second contact region and a second outer peripheral region. The second contact region overlaps with the first contact region in a perpendicular direction. A second contact is disposed in the second contact region. The second outer peripheral region overlaps with the first outer peripheral region in the perpendicular direction. A pressing member contacts the second outer peripheral region without contacting the second contact region. The pressing member presses the second outer peripheral region toward the actuator member. A thermal interface material contacts the second contact region without contacting the second outer peripheral region. The thermal interface material has a lower hardness than the pressing member.