Liquid Ejection Head Pressure Adjustment for Rapid Ink Circulation
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Solution Overview
Problem
Existing liquid ejection apparatuses face long downtime due to the need for extensive circulation paths to re-disperse precipitated components and prevent ink thickening, which lowers productivity.
Innovation Solution
A liquid ejection head and apparatus with a circulation path that includes a supply channel, collection channel, circulation pump, and pressure adjustment units, where the pressure relationships are optimized to facilitate rapid circulation, reducing downtime and preventing ink thickening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If long circulation paths are formed to re-disperse precipitated components and suppress ink thickening, then the liquid circulation effectiveness is improved, but the downtime increases and productivity decreases
Solution Approach 1:
The circulation path is divided into two separate channels: a supply channel for delivering liquid to the ejection head and a collection channel for returning liquid to the storage unit. This segmentation allows independent optimization of each channel's function, enabling effective circulation without requiring excessively long paths, thus reducing downtime while maintaining circulation effectiveness.
Solution Approach 2:
The patent introduces a vertical arrangement where the ejection head is positioned above the liquid storage unit, creating a height difference that enables gravitational flow. This dimensional change allows the circulation path to be shortened by utilizing vertical space rather than extending horizontal paths, thereby reducing downtime while maintaining circulation effectiveness.
2Stability of the object's composition
If long circulation paths are formed to re-disperse precipitated components, then the ink fluidity is improved, but the apparatus size increases
Solution Approach 1:
By segmenting the circulation path into supply and collection channels with distinct functions, the patent enables compact routing of each channel. The supply channel can be optimized for efficient liquid delivery while the collection channel handles return flow, allowing both to be shortened and arranged compactly, thus maintaining ink fluidity without increasing apparatus size.
Solution Approach 2:
The circulation channels are arranged in a nested or integrated manner within the ejection head structure, where channels are routed through available spaces and layers. This nesting approach allows the circulation path to be compactly integrated into the existing apparatus structure, maintaining ink fluidity through effective circulation while minimizing additional apparatus volume.
3Reliability
If circulation paths are extended to ensure complete liquid circulation, then the precipitated component re-dispersion is improved, but the circulation time increases
Solution Approach 1:
The circulation path is segmented into supply and collection channels that operate in parallel rather than sequentially. This segmentation allows liquid to be supplied to multiple ejection ports simultaneously while return flow is collected concurrently, significantly reducing the total circulation time required for effective re-dispersion of precipitated components.
Solution Approach 2:
The circulation system is designed to maintain continuous liquid flow through the ejection head during operation. The supply channel continuously delivers fresh liquid while the collection channel continuously removes used liquid, ensuring constant circulation action that effectively re-disperses precipitated components without requiring extended circulation cycles.
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
The optimized circulation path allows for efficient re-dispersion of precipitated components and suppression of ink thickening, enhancing productivity by minimizing downtime and apparatus size while maintaining ink fluidity and ejection characteristics.
Implementation Method 1
a circulation pump which supplies the liquid collected through the collection channel to the supply channel
Implementation Method 2
a pressure adjustment unit configured to adjust a pressure on the liquid supplied to the supply channel
Implementation Method 3
a pressure P21 on the liquid supplied to the pressure chamber from the pressure adjustment unit through the supply channel in a state where the circulation pump is stopped, a pressure P22 on the liquid supplied to the pressure chamber from the pressure adjustment unit through the supply channel in a state where the circulation pump is driven, and a pressure loss ΔP from the pressure adjustment unit to the pressure chamber in the state where the circulation pump is driven have relationships of P22>P21 and P22-P21>ΔP
Data Source
AI summary
A liquid ejection head includes a pressure chamber communicating with an ejection port, an ejection element which ejects the liquid from the port, and a circulation path for the liquid including the chamber. The path includes a supply channel for supplying the liquid to the chamber, a collection channel for collecting the liquid from the chamber, a circulation pump which supplies the collected liquid to the supply channel, and a pressure adjustment unit configured to adjust a pressure on the liquid to be supplied to the supply channel. A pressure P21 on the liquid supplied to the chamber while the pump is stopped, a pressure P22 on the liquid supplied to the chamber while the pump is driven, and a pressure loss ΔP from the adjustment unit to the chamber while the pump is driven satisfy P22>P21 and P22−ΔP<0.