Liquid Ejection Head Pillar Clearance Design
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Solution Overview
Problem
Existing liquid ejection heads face performance degradation due to foreign matter caught between pillar structures or between pillar structures and sidewalls, causing resistance and hindering fluid movement, which results in deteriorated ejection performance.
Innovation Solution
The liquid ejection head incorporates a configuration with first and second pillar structures arranged between supply and discharge ports and pressure compartments, where the longest clearance between the pillar structures is smaller than the shortest clearance between the flow path walls and the pillar structures, preventing foreign matter from being caught and reducing resistance during the ejection operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pillar structures are provided near the inlet of each fluid ejection chamber to catch foreign matter, then foreign matter blocking is prevented, but foreign matter caught between pillar structures acts as resistance and hinders liquid movement, deteriorating ejection performance
Solution Approach 1:
The patent extracts the filtering function from the pillar structures by providing a separate filter member in the liquid supply path. This allows the pillar structures to be removed or reduced in number, eliminating the harmful resistance they create while maintaining foreign matter catching capability through the dedicated filter member.
Solution Approach 2:
The patent introduces a filter member as an intermediary element between the liquid supply and the ejection chambers. This filter member specifically handles the foreign matter filtration task, allowing the pillar structures to focus on their primary structural function without creating flow resistance.
2Reliability
If pillar structures are arranged closely to effectively filter foreign matter, then filtering capability is improved, but clearance between pillar structures becomes small causing increased fluid resistance
Solution Approach 1:
The filtering function is extracted from the pillar structures and assigned to a dedicated filter member. This allows the pillar structures to be spaced farther apart, reducing fluid resistance while the filter member maintains effective filtering capability through its specific design and placement in the liquid supply path.
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 maintains consistent flow rates and prevents foreign matter from blocking the flow path, reducing the occurrence of satellite droplets and ink mist, thus maintaining optimal liquid ejection performance.
Implementation Method 1
a bubble is formed by heating the liquid in the pressure compartment with an energy generating element
Data Source
AI summary
A liquid ejection head includes ejection nozzles, pressure compartments, a supply port, and first pillar structures. The pressure compartments which each communicate with a corresponding ejection nozzle of the ejection nozzles and are each combined with an energy generating element configured to generates ejection energy for ejecting liquid. The supply port supplies the liquid to the pressure compartments. The first pillar structures are arranged between the supply port and the pressure compartments. The pressure compartments is each defined by a flow path walls arranged in line and parallel to each other. A liquid flow path is formed and configured to allow the liquid to flow through the liquid flow path from the at least one supply port via the first pillar structures into the pressure compartments. A longest clearance between the first pillar structures is smaller than a shortest clearance between the flow path walls and the first pillar structures.