Liquid Ejection Head Recirculation for Ejection-Port Viscosity Control
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Solution Overview
Problem
Existing liquid ejection heads fail to effectively suppress the increase in viscosity of liquid near the ejection port due to evaporation of volatile components, leading to poor ejection speed and accuracy.
Innovation Solution
A liquid ejection head design featuring individual channels with microcirculation and a common channel with macrocirculation, utilizing supply and correct through-holes to recirculate ink, ensuring efficient replacement of concentrated ink with fresh ink.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If microcirculation is implemented in individual channels, then liquid circulation is improved, but concentrated ink may reflow into individual channels from outlets
Solution Approach 1:
The circulation system is segmented into two independent parts: individual circulation channels for microcirculation and a common circulation channel for macrocirculation. This segmentation allows concentrated ink to be discharged from individual channels into the common channel without flowing back, while fresh ink is supplied through the common channel to individual channels, solving the reflow problem while maintaining circulation efficiency
Solution Approach 2:
The common circulation channel acts as an intermediary between individual channels and the ink supply system. It receives concentrated ink from individual channels and supplies fresh ink to them, preventing direct reflow while maintaining efficient liquid circulation and viscosity control
2Productivity
If macrocirculation is implemented in common channel, then liquid circulation is improved, but concentrated ink accumulates at downstream portions
Solution Approach 1:
The circulation path is segmented such that individual channels discharge into the common channel rather than forming a closed loop. This one-way discharge prevents concentrated ink accumulation at downstream portions while maintaining efficient macrocirculation through the common channel
Solution Approach 2:
The system implements feedback by continuously supplying fresh ink from the ink supply through the common channel to individual channels, replacing concentrated ink and maintaining appropriate viscosity near ejection ports while allowing concentrated ink to be discharged into the common channel
3Productivity
If separate microcirculation and macrocirculation regions are provided, then liquid circulation is improved, but concentrated ink can reflow from individual channels
Solution Approach 1:
The individual circulation channels and common circulation channel are merged into an integrated circulation system where concentrated ink from individual channels flows into the common channel, and fresh ink is distributed back to individual channels, preventing reflow while maintaining efficient circulation
Solution Approach 2:
The common circulation channel serves as an intermediary that receives concentrated ink from individual channels and supplies fresh ink to them, preventing reflow while maintaining the benefits of separate microcirculation and macrocirculation regions
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 design effectively suppresses the viscosity increase near the ejection port, enhancing ejection speed and accuracy by efficiently replacing concentrated ink with fresh ink, thereby reducing clogging and improving printing quality.
Implementation Method 1
a supply port which penetrates the substrate and supplies the liquid to the connection area
Implementation Method 2
a correct port which penetrates the substrate and corrects the liquid from the connection areas
Implementation Method 3
each of the plurality of individual circulation channels communicating with an ejection port of a liquid and recirculating the liquid
Implementation Method 4
a common circulation channel communicating with the plurality of individual circulation channels and recirculating the liquid
Data Source
AI summary
The liquid ejection head includes a substrate having a first surface and a second surface which is a back surface of the first surface, a plurality of individual channels provided on the first surface, communicating with the ejection port, and recirculating the liquid, and a circulation channel communicating with the plurality of individual channels and recirculating the liquid. The circulation channel is provided on the first surface and has a connection region communicating with the outlet ports of the plurality of individual channels, a supply through-hole penetrating the substrate and supplying the liquid to the connection region, and a correct through-hole penetrating the substrate and correcting the liquid from the connection region.