Liquid Ejection Head Stacked Pressure Chambers
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Solution Overview
Problem
Existing liquid ejection heads face challenges in achieving high-density placement of ejection orifices due to the large number of pressure chambers and flow paths required for efficient ink circulation, which often results in ejection failure caused by ink viscosity increases as volatile components evaporate.
Innovation Solution
The design includes a first and second pressure chamber row overlapping the supply and recovery flow paths, respectively, allowing for efficient ink circulation and high-density ejection orifice placement by alternating the arrangement of pressure chambers and flow paths, enabling continuous ink flow and preventing ejection failure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a circulation mechanism with supply and recovery flow paths is added to prevent ejection failure, then ejection reliability is improved, but device complexity increases due to the large number of pressure chambers and flow paths required
Solution Approach 1:
The patent transitions from a planar arrangement to a three-dimensional stacked configuration where pressure chambers are arranged in multiple layers (first pressure chamber row and second pressure chamber row) that overlap with flow paths when viewed from the ejection direction. This vertical stacking enables high-density ejection orifice placement while maintaining circulation functionality without increasing planar footprint.
Solution Approach 2:
The patent nests pressure chambers within the flow path structure by positioning the first and second pressure chamber rows to overlap with the supply and recovery flow paths respectively. This nested arrangement allows multiple functional components to occupy the same spatial envelope, reducing overall device complexity while maintaining all necessary circulation pathways.
2Manufacturing precision
If ejection orifices are disposed with high density to achieve high image quality, then image quality is improved, but the number of pressure chambers and piezoelectric elements increases, making efficient disposition difficult
Solution Approach 1:
The patent achieves high-density ejection orifice placement by utilizing the third dimension (ejection direction) to stack pressure chamber rows vertically. This allows numerous ejection orifices to be arranged in a compact footprint while maintaining one-to-one correspondence with pressure chambers and piezoelectric elements, resolving the conflict between high density and component disposition efficiency.
Solution Approach 2:
The patent merges the functions of multiple pressure chamber rows with flow paths by arranging them to overlap in the ejection direction. This consolidation allows the circulation mechanism to serve multiple pressure chambers simultaneously, reducing the total number of separate flow path segments and piezoelectric element groups needed for high-density configurations.
3Ease of manufacture
If individual wirings are disposed on the surface where piezoelectric elements are disposed, then electrical connection is achieved, but pressure chambers cannot be disposed in that region, reducing ejection orifice density
Solution Approach 1:
The patent resolves the spatial conflict by stacking pressure chamber rows in the ejection direction to overlap with flow paths, thereby creating vertical separation between the wiring layer and pressure chamber regions. This three-dimensional arrangement allows individual wirings to be disposed on the piezoelectric element surface without obstructing pressure chamber placement, enabling both electrical connection and high ejection orifice density.
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 enables high-density placement of ejection orifices, maintaining efficient ink supply and recovery, and preventing ejection failure by managing ink viscosity through continuous flow, thereby enhancing the compatibility of the liquid ejection head with high image quality requirements.
Implementation Method 1
piezoelectric elements that contract the pressure chambers, and a plate in which a plurality of ejection orifices are formed, and ejects ink in the pressure chambers as liquid droplets from predetermined ejection orifices by changing capacities of the pressure chambers by the piezoelectric elements
Data Source
AI summary
A liquid ejection head includes a first pressure chamber row having a plurality of first pressure chambers respectively communicating with a plurality of ejection orifices that eject liquid and arranged along a predetermined direction, a second pressure chamber row having a plurality of second pressure chambers respectively communicating with a plurality of ejection orifices that eject liquid and arranged along the predetermined direction, a first flow path for supplying the liquid to the plurality of first pressure chambers, and a second flow path for recovering the liquid from the plurality of second pressure chambers. Part of the first pressure chamber row is disposed to overlap the first flow path, and part of the second pressure chamber row is disposed to overlap the second flow path, as viewed from an ejection direction of the liquid.