Liquid Ejection Head Capacitor Placement for Compact Design
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Solution Overview
Problem
Existing liquid ejection heads face challenges in downsizing due to the need to accommodate a capacitor near the element substrate without increasing the head's size, while also protecting the capacitor from ink and ensuring it does not interfere with other components.
Innovation Solution
The liquid ejection head incorporates a flexible wiring board with a slanted mount portion for the capacitor, positioned to avoid interference with the support member, and features a concave portion on the support member's side surface to prevent contact with the sealant, allowing for compact design without compromising functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the capacitor is sealed with a sealant and disposed in a concave portion of the support member, then the capacitor is protected from ink contact, but the ejection head size increases due to side-by-side arrangement of element substrate and capacitor
Solution Approach 1:
The patent changes the spatial arrangement from a side-by-side configuration (in the plane of the element substrate) to a stacked configuration (in the thickness direction). The capacitor is disposed on the back surface of the element substrate, utilizing the Z-axis dimension rather than expanding the X-Y plane area. This dimensional transition allows the capacitor to be positioned near the element substrate electrically while maintaining a compact overall head size.
Solution Approach 2:
The capacitor is integrated into the existing structure by placing it on the back surface of the element substrate, effectively nesting the capacitor within the same structural footprint as the element substrate. The flexible wiring board extends from the element substrate to reach the capacitor, creating a compact integrated assembly where components are nested rather than externally arranged.
2Reliability
If the capacitor is mounted at the flexible wiring board near the element substrate, then the capacitor can be positioned close to reduce ringing, but the capacitor may contact ink or other members without proper protection
Solution Approach 1:
The capacitor is extracted from the conventional position on the flexible wiring board and relocated to the back surface of the element substrate. This extraction from the original position allows the capacitor to be closer to the element substrate for effective ringing reduction while being physically separated from the ink ejection area, thereby eliminating the risk of ink contact damage.
3Reliability
If the element substrate and capacitor are disposed side by side on the support member, then the capacitor can be protected with a sealant, but it becomes difficult to downsize the ejection head
Solution Approach 1:
The patent transitions from a planar side-by-side arrangement to a three-dimensional stacked arrangement. The capacitor is positioned on the back surface of the element substrate, utilizing the thickness direction (Z-axis) rather than expanding the lateral dimensions (X-Y plane). This vertical stacking enables compact integration without increasing the overall length or width of the ejection head.
Data Source
AI summary
Provided is a liquid ejection head and a method for manufacturing the liquid ejection head, in which a capacitor can be disposed near an element substrate without increasing the size of the ejection head. To this end, a side surface of a support member includes a concave portion at a position facing an electronic component, the side surface intersecting with a support surface where the element substrate is supported.