Liquid Ejection Head Compliance Substrate Placement
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Solution Overview
Problem
Existing liquid ejection heads face limitations in accommodating pressure variations in the liquid reservoir, particularly due to the constraints imposed by the position and size of the inlet, which restrict the area and form of the compliance substrate, affecting ejection stability and head size.
Innovation Solution
The liquid ejection head design incorporates a first compliance substrate on the side opposite to the inlet, allowing for increased area and effective pressure variation accommodation, with a second compliance substrate positioned closer to the pressure chamber to enhance stability, and a modular case member structure that reduces overall size and minimizes moisture evaporation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the compliance substrate is disposed on the same side as that of the inlet, then the structure is simplified, but the area of the active part is limited by the inlet position and size
Solution Approach 1:
The patent applies inversion by placing the compliance substrate on the side opposite to the inlet rather than on the same side. This reverses the conventional arrangement and allows the active part to extend freely without being constrained by the inlet position, thereby maximizing the active area while maintaining structural simplicity.
2Reliability
If the active part area of the compliance substrate is increased, then the pressure variation accommodation effect is improved, but the head size increases
Solution Approach 1:
The patent utilizes the space dimension by placing the compliance substrate on the opposite side of the inlet, effectively using the depth dimension of the reservoir rather than expanding the lateral area. This allows the active part to have a large effective area for pressure accommodation without increasing the overall head footprint.
Solution Approach 2:
The compliance substrate is nested within the reservoir structure, utilizing the existing spatial configuration. By positioning it on the opposite side of the inlet, the active part can be accommodated within the reservoir's depth, effectively nesting the compliance function within the existing head geometry without external expansion.
3Ease of manufacture
If the compliance substrate is placed on the same side as the inlet, then the inlet structure is simplified, but pressure variation is not effectively transmitted to the compliance substrate
Solution Approach 1:
The patent inverts the placement strategy by positioning the compliance substrate on the opposite side of the inlet. This reversal ensures that pressure variations generated at the inlet are transmitted through the liquid column to the compliance substrate, improving pressure transmission efficiency while maintaining inlet structure simplicity.
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 improves ejection stability and reduces the size of the liquid ejection head while effectively accommodating pressure variations, allowing for better ink distribution and reduced ink waste through optimized compliance substrate placement and material usage.
Implementation Method 1
pressure variation in the liquid reservoir caused by a liquid introduced from the inlet of the liquid reservoir is accommodated by the compliance substrate
Implementation Method 2
pressure variation of the pressure chamber transmitted to the second reservoir via the individual channel is effectively accommodated by the second compliance substrate
Data Source
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AI summary
A liquid ejection head, which includes a driving element that changes pressure in a pressure chamber and causes a liquid to be ejected from a nozzle, an individual channel that communicates with the pressure chamber, and a liquid reservoir that supplies via the individual channel the liquid introduced from an inlet to the pressure chamber. The liquid reservoir includes a first reservoir disposed on the inlet side, a second reservoir disposed on the individual channel side, and an intermediate reservoir that communicates with the first reservoir and the second reservoir. At least a part of the first reservoir overlaps the second reservoir when seen in plan view. A first compliance substrate is provided in the first reservoir on the second reservoir side on the side opposite to the inlet. A second compliance substrate is provided in the second reservoir on the side opposite to the first reservoir.