Inclined Element Substrates for Compact Liquid Ejection Heads
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Solution Overview
Problem
Existing liquid ejection heads face challenges in reducing manufacturing costs while maintaining reliability of adhesion and electrical connections, particularly when downsizing the element substrate, which can lead to nonuniformity and increased sealing requirements.
Innovation Solution
A liquid ejection head design with multiple sets of element substrates arrayed in a direction inclined to the ejection element array, where electrical wiring members extend intersecting this direction, providing reliable connections and minimizing substrate size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the element substrate is downsized to reduce manufacturing cost, then the manufacturing cost is reduced, but the adhesion surface area between the element substrate and flow path member is reduced, leading to reduced adhesion reliability
Solution Approach 1:
The patent changes the arrangement dimension of element substrates from linear (in-line) to angular (inclined at specific angles of 30-60 degrees relative to the short side). This dimensional change in arrangement allows the substrates to be positioned such that their adhesion surfaces fully contact the flow path member, maintaining adhesion reliability while enabling substrate downsizing and compact head configuration.
2Device complexity
If multiple types of liquid are ejected by using one print chip, then the device complexity is reduced, but nonuniformity occurs in ejection
Solution Approach 1:
The patent divides the ejection function by assigning each element substrate to eject only one type of liquid (single-color ejection). Multiple substrates are arranged in parallel, each dedicated to a specific liquid type. This segmentation eliminates cross-contamination and nonuniformity issues that occur when multiple liquid types share a single substrate, while maintaining overall system simplicity through modular substrate design.
3Reliability
If the TAB film is connected across the entire area of the long side in the print chip, then the electrical connection is secured, but the sealing area for the entire long side is necessary, making it difficult to downsize the element substrate
Solution Approach 1:
The patent extracts the electrical connection function from the traditional TAB film that spans the entire long side, and relocates it to angularly positioned connection portions at specific corners of the element substrate. This extraction allows the connection area to be localized rather than distributed across the entire edge, enabling reduced substrate size while maintaining reliable electrical connections through concentrated connection points.
4Reliability
If element substrates are arranged in-line to secure adhesion surface area, then the adhesion reliability is improved, but the liquid ejection head becomes larger and cannot be downsized
Solution Approach 1:
The patent introduces asymmetric angular arrangement of element substrates relative to the flow path member, with substrates inclined at specific angles (30-60 degrees) rather than being arranged linearly. This asymmetric positioning allows compact packing of multiple substrates in a smaller overall head volume while ensuring each substrate maintains full adhesion contact with the flow path member through its inclined orientation.
Data Source
AI summary
A liquid ejection head that is compact and whose reliability of an electrical connection portion is high includes a plurality of sets of element substrates in which a plurality of ejection elements ejecting a liquid of the same type is arrayed and a plurality of sets of electrical wiring members for supplying electric power to the element substrates. Each element substrate is arrayed in a second direction inclined with respect to a first direction in which the plurality of ejection elements is arrayed. Each electrical wiring member is connected to a terminal arranged at one end portion of the corresponding element substrate and extends in a third direction intersecting the first direction and the second direction.