Liquid Ejection Head Adhesive Wall Design
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Solution Overview
Problem
In liquid ejection heads, the sealant used to protect the electric connection part can expand or shrink, applying external forces to the recording element substrate, which may deform it due to the demand for downsizing and elongation of energy generating elements, leading to issues with adhesive distribution and sealant extension.
Innovation Solution
A liquid ejection head design featuring a support member with a recess and a projection-shaped adhesive application surface, where the adhesive is applied to a first region covered by the recording element substrate and a second region extending to the projection, forming a wall to restrict sealant extension and ensure minimal adhesive usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a projection is provided at the inner side surface of the recess to restrict sealant extension, then the sealant hardly contacts the recording element substrate, but the adhesive extends to the entire bottom surface of the recess isotropically, requiring a large amount of adhesive
Solution Approach 1:
The invention applies local quality by providing a projection at a specific location (inner side surface of the recess near the electric connection part) rather than uniformly across the entire surface. This localized projection restricts sealant extension only where needed, while the adhesive application surface is designed with a first region (covered by recording element substrate) and a second region (extending to the projection) to control adhesive flow directionally, reducing overall adhesive consumption.
Solution Approach 2:
The adhesive application surface is segmented into two distinct regions: the first region covered by the recording element substrate and the second region extending to the projection. This segmentation allows the adhesive to be applied in a controlled manner, flowing primarily toward the projection to form the wall, rather than spreading isotropically across the entire bottom surface, thereby reducing the total adhesive amount required.
2Speed
If the recording element substrate is elongated to increase recording speed, then the recording speed increases, but the bonding area between the recording element substrate and the support member is increased, requiring a larger amount of adhesive
Solution Approach 1:
The invention addresses the increased adhesive requirement due to substrate elongation by implementing local quality through the projection and segmented adhesive application surface. The projection is strategically positioned to restrict sealant extension at critical areas, while the adhesive flows directionally toward the projection, ensuring adequate bonding without requiring proportionally increased adhesive amounts across the entire elongated substrate.
Solution Approach 2:
The projection is pre-formed on the support member before adhesive application. This preliminary action creates a predetermined barrier that guides adhesive flow and forms the wall structure, ensuring that even with an elongated recording element substrate, the adhesive is efficiently utilized to create sufficient bonding without excessive consumption.
3Strength
If the adhesive is applied to ensure sufficient bonding height, then the bonding strength is improved, but the adhesive may flow out from the region near the recording element substrate to the inner side surface of the recess, making it difficult to ensure the required adhesive height
Solution Approach 1:
The projection is pre-formed on the support member before adhesive application, creating a predetermined structure that guides adhesive flow. When adhesive is applied to the first region, it naturally flows toward the projection and forms a wall against it, ensuring sufficient bonding height is achieved without the adhesive flowing uncontrollably to the inner side surface of the recess.
Solution Approach 2:
The projection acts as an intermediary structure between the adhesive and the inner side surface of the recess. It intercepts the adhesive flow, causing the adhesive to accumulate and form the wall against the projection rather than flowing freely to the inner side surface, thereby maintaining controlled adhesive height and ensuring sufficient bonding strength.
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 design effectively restricts sealant extension, maintains the required adhesive height for bonding, and prevents deformation of the recording element substrate, while minimizing adhesive usage and ensuring reliable electrical connections.
Implementation Method 1
an adhesive being applied to the adhesive application surface, the adhesive bonding the recording element substrate
Data Source
AI summary
A liquid ejection head includes a recording element substrate that ejects liquid; an electric wiring substrate electrically connected with the recording element substrate; a support member having a recess that houses the recording element substrate; and a sealant that seals an electric connection part between both the substrates. The support member has a projection-shaped adhesive application surface at a bottom surface of the recess, on which an adhesive for bonding the recording element substrate is applied; and a projection projecting from an inner side surface of the recess near the electric connection part toward the adhesive application surface, which has a first region that is covered with the recording element substrate, and a second region extending from the first region to the projection having a wall formed of the adhesive and closing a gap between the projection and a side surface of the recording element substrate facing the projection.