Liquid Ejection Head Passage Geometry for Ink Quality
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing liquid ejection heads face issues with quality variations of liquid adjacent to the ejection opening due to passage and opening shapes, leading to ink thickening and uneven ink density, which results in printing defects.
Innovation Solution
A liquid ejection head design where the expression H−0.34×P−0.66×W>1.7 is satisfied, with H being the passage height, P the ejection opening length, and W the passage length, ensuring that the liquid flows into the ejection opening and returns to the passage, maintaining optimal ink flow and preventing thickening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If liquid is allowed to flow through a passage between an ejection opening and an energy generation element, then clogging of the ejection opening due to thickened ink is prevented, but quality of liquid adjacent to the ejection opening varies depending on shapes of the passage or ejection opening
Solution Approach 1:
The invention changes the geometric parameters of the passage and ejection opening portion to satisfy a specific mathematical relationship (H−0.34×P−0.66×W>1.7), where H is passage height, P is ejection opening length in ejection direction, and W is passage length in flow direction. This parameter optimization ensures uniform liquid quality while preventing clogging.
Solution Approach 2:
The invention introduces a specific dimensional relationship between passage height, ejection opening length, and passage length through the mathematical expression. By controlling the interplay of these three dimensions, the invention achieves both clogging prevention and uniform liquid quality distribution.
2Productivity
If liquid flows through the passage, then new liquid is supplied to replace evaporated moisture, but ink may be thickened or color material concentration may be changed resulting in uneven density
Solution Approach 1:
The invention optimizes the passage geometry parameters (H, P, W) to satisfy the relationship H−0.34×P−0.66×W>1.7, which ensures that liquid flows uniformly through the passage without localized thickening or concentration changes, maintaining consistent ink quality during continuous supply.
Solution Approach 2:
The invention creates a controlled flow path where liquid continuously circulates between the passage and ejection opening, ensuring that evaporated moisture is replaced and concentration uniformity is maintained through the optimized geometric configuration that promotes even flow distribution.
3Manufacturing precision
If the passage dimensions are optimized to prevent ink thickening, then liquid quality uniformity is improved, but the passage design becomes more constrained
Solution Approach 1:
The invention establishes a specific mathematical relationship (H−0.34×P−0.66×W>1.7) that defines the optimal parameter range for passage height, ejection opening length, and passage length. This relationship provides clear design guidelines that balance uniform liquid quality with practical design freedom.
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 design effectively suppresses ink thickening and color unevenness, ensuring consistent ink quality and improved printing performance by maintaining the liquid's flow and preventing evaporation-induced viscosity increases.
Implementation Method 1
moisture, etc. of ink evaporates due to heat generated as a result of the ejection operation
Data Source
AI summary
A liquid ejection head includes an ejection opening; a passage in which an energy generation element is disposed; an ejection opening portion that allows communication between the ejection opening and the passage; a supply passage for allowing the liquid to flow into the passage; and an outflow passage for allowing the liquid to flow out to the outside. An expression of H−0.34×P−0.66×W>1.7 is satisfied when a height of the passage is set to H [μm], a length of the ejection opening portion is set to P [μm], and a length of the ejection opening portion is set to W [μm].