Liquid Ejection Head With Varying Cross-Sectional Area Passages
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Solution Overview
Problem
In liquid ejection devices, ink supply and discharge passages experience reduced flow efficiency as they increase in distance from the opening, leading to uneven ink distribution and flow resistance variations among passages.
Innovation Solution
The design includes second supply and discharge passages with varying cross-sectional areas along their length, increasing in the sheet width direction towards the downstream side, ensuring uniform ink flow resistance and distribution across all passages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the second supply passage and second discharge passage are designed with constant cross-sectional area, then the device complexity is reduced, but the ink flow becomes uneven among passages at different distances from the opening
Solution Approach 1:
The second supply passage and second discharge passage are designed with varying cross-sectional areas at different locations. Specifically, the cross-sectional area changes along the passage length to compensate for distance-related flow resistance, ensuring that passages farther from the opening receive adequate ink flow. This local variation in geometric properties resolves the contradiction by achieving uniform ink distribution without requiring complex additional components.
Solution Approach 2:
The patent modifies the geometric parameters of the second supply passage and second discharge passage by varying their cross-sectional areas. The cross-sectional area is adjusted as a function of distance from the opening, with passages located farther away having larger cross-sectional areas to offset increased flow resistance. This parameter change approach enables uniform ink flow distribution while maintaining a relatively simple overall passage structure.
2Productivity
If passages are arranged farther from the opening to increase nozzle density, then the productivity is improved, but the flow resistance increases and ink distribution becomes uneven
Solution Approach 1:
The passage design implements local quality variation by adjusting the cross-sectional area of the second supply passage and second discharge passage at different locations. Passages located farther from the opening have larger cross-sectional areas, creating a gradient that compensates for the increased distance and flow resistance. This enables high nozzle density with uniform ink distribution across all passages.
3Manufacturing precision
If the cross-sectional area of second supply passage and second discharge passage is increased, then the flow resistance is reduced, but the device complexity and passage dimensions increase
Solution Approach 1:
Rather than uniformly increasing the cross-sectional area of all passages, the patent applies local quality variation by adjusting the cross-sectional area only where needed - specifically, passages farther from the opening have larger areas while those closer maintain smaller areas. This targeted approach reduces overall passage dimensions while achieving uniform ink flow distribution.
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 ensures uniform ink circulation and flow efficiency among individual passages, reducing flow resistance and maintaining consistent ink distribution, even as passages move further from the supply or discharge points.
Implementation Method 1
the cross-sectional area of the second supply passage at the first portion differs from the cross-sectional area of the second supply passage at the second portion, and/or (B) where an area of a cross section of the second discharge passage on a plane orthogonal to the second direction is defined as a cross-sectional area of the second discharge passage and two portions of the second discharge passage spaced apart from each other in the second direction are respectively defined as a first portion and a second portion, the cross-sectional area of the second discharge passage at the first portion differs from the cross-sectional area of the second discharge passage at the second portion
Data Source
AI summary
A liquid ejection head, including: first supply passages and first discharge passages extending in a first direction and arranged in a second direction intersecting the first direction; and a second supply passage extending in the second direction and communicating with the first supply passages to supply the liquid thereto and a second discharge passage extending in the second direction and communicating with the first discharge passages to discharge the liquid therefrom, wherein (A) a cross-sectional area of the second supply passage on a plane orthogonal to the second direction at a first portion thereof differs from that at a second portion thereof spaced apart from the first portion in the second direction and/or (B) a cross-sectional area of the second discharge passage on the plane at a first portion thereof differs from that at a second portion thereof spaced apart from the first portion in the second direction.