Liquid Ejection Head Pressure Distribution via Segmented Supply
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Solution Overview
Problem
Inkjet printing technologies face challenges in maintaining consistent ejection characteristics and color concentration due to uneven circulation flow and pressure changes in densely arranged ejection openings, leading to variations in ink thickness and ejection speed.
Innovation Solution
A liquid ejection head design with a configuration that includes multiple ejection openings, pressure chambers, supply and collection passages, and communication openings to manage ink flow and pressure, ensuring consistent circulation flow and minimizing pressure differences between chambers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the number of ejection openings is increased to improve printing resolution, then printing accuracy is improved, but pressure distribution becomes uneven and circulation flow varies between chambers
Solution Approach 1:
The liquid ejection head is divided into multiple independent ejection units, each with its own pressure chamber and ink supply passage. This segmentation allows each unit to maintain independent pressure control, preventing pressure distribution issues from affecting the entire head when the number of ejection openings is increased.
Solution Approach 2:
Each ejection unit is designed with locally optimized ink supply passages and communication openings positioned at specific locations to ensure uniform pressure distribution within each pressure chamber. The local structure is tailored to maintain consistent circulation flow regardless of the total number of ejection openings in the system.
2Manufacturing precision
If ejection opening rows are densely arranged to improve printing resolution, then printing accuracy is improved, but passage width must be reduced causing greater pressure loss
Solution Approach 1:
The ink supply passages are designed to extend in multiple directions (row direction and intermediate direction) rather than solely in the row direction. This multi-dimensional passage arrangement allows ink to reach ejection openings more efficiently, reducing pressure loss even when passages are narrowed due to dense ejection opening arrangement.
Solution Approach 2:
Communication openings are introduced as intermediary structures connecting the ink supply passage to the pressure chamber. These communication openings facilitate efficient ink flow transfer, reducing pressure loss in the narrowed passages by providing direct flow paths from the supply passage to the pressure chamber.
3Stability of the object's composition
If circulation flow amount in each pressure chamber becomes uneven, then ejection characteristic consistency deteriorates, but increasing passage width to improve flow uniformity reduces ejection opening density
Solution Approach 1:
By segmenting the liquid ejection head into multiple independent ejection units with separate ink supply passages, the system can maintain consistent circulation flow in each unit without requiring increased overall passage width. Each segmented unit's flow characteristics are independently controlled, preserving ejection consistency while maintaining high ejection opening density.
Solution Approach 2:
Communication openings serve as intermediary structures that optimize the flow path from the ink supply passage to the pressure chamber. They ensure uniform circulation flow distribution within each pressure chamber by providing direct flow access, achieving flow consistency without increasing passage width that would reduce ejection opening density.
Data Source
AI summary
Provided is a liquid ejection head comprising: an ejection opening row along a first direction; a pressure chamber with print-element; a passage communicating with the pressure chamber; a supply opening row along the first direction with supply openings extending in a second direction to supply liquid to the passage; a collection opening row along the first direction with collection openings extending in the second direction to collect a liquid from the passage; a first common supply passage along the first direction to supply a liquid to the supply opening row; a first common collection passage along the first direction to collect a liquid from the collection opening row; a first supply side communication opening extending in the second direction to supply a liquid to the first common supply passage; and a first collection side communication opening extending in the second direction to collect a liquid from the first common collection passage, wherein at least one of the first supply side communication opening and the first collection side communication opening is provided at a plurality of positions.