Liquid Ejection Head Bubble Removal Through Permeable Partition

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Solution Overview

Problem

Bubbles entering liquid ejection heads during replacement or maintenance can lead to insufficient ejection pressure and liquid leakage, affecting the stability and performance of liquid ejection apparatuses.

Innovation Solution

A configuration with a filter chamber and gas collection hollow portion using a permeable partition to trap and discharge bubbles, maintaining pressure differences to facilitate bubble permeation and prevent leakage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a filter chamber and gas collection hollow portion are added to trap and discharge bubbles, then bubble removal capability is improved, but device complexity increases

Engineering Contradiction:
Improvebubble removal capabilityVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The gas collection hollow portion is nested within the filter chamber structure, with the permeable partition integrating the gas collection function into the existing filter chamber. This nested arrangement allows bubble trapping and collection without adding a completely separate external component, thereby improving bubble removal capability while minimizing the increase in overall device complexity.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

A permeable partition is used between the filter chamber and gas collection hollow portion to allow gas permeation while maintaining structural separation. The porous nature of the partition enables automatic bubble discharge through pressure differential without requiring complex active control mechanisms, thus improving reliability while keeping the device structure relatively simple.

Inventive Principle:
Principle #31Porous materials

2Productivity

If pressure differential is maintained to facilitate bubble permeation, then bubble discharge efficiency is improved, but energy consumption increases

Engineering Contradiction:
Improvebubble discharge efficiencyVSAvoidenergy consumption
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The system utilizes the natural pressure differential that arises during liquid ejection operations to drive bubble permeation through the permeable partition. The ejection process itself generates the pressure conditions needed for bubble discharge, eliminating the need for separate energy-consuming pump or vacuum systems. This self-service mechanism improves bubble discharge efficiency without significantly increasing energy consumption.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The invention employs pneumatic pressure differential created during normal ejection operations to facilitate bubble movement through the permeable partition. By utilizing the existing hydraulic/pneumatic conditions of the ejection system, bubble discharge is achieved without requiring additional energy input, thus maintaining high productivity while avoiding increased energy consumption.

Inventive Principle:
Principle #29Pneumatics and hydraulics

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

Enhances the stability and reliability of liquid ejection heads by effectively discharging bubbles, ensuring consistent ejection performance and preventing liquid leakage.

Implementation Method 1

the pressure inside the gas collection hollow portion is set to be lower than the pressure inside the filter chamber to cause the gas in the filter chamber to permeate through the permeable partition by means of the pressure difference

Methodology Applied
Scientific EffectPressure difference: Pressure Gradient

Data Source

PatentEP4624173A1Liquid ejection head and liquid ejection apparatus
Publication Date: 2025.10.01 CANON KK
  • EP4624173A1 patent drawingFigure 1A~1B
  • EP4624173A1 patent drawingFigure 2
  • EP4624173A1 patent drawingFigure 3

AI summary

Provided is a liquid ejection head (1) in which P1 × V4 > P1 × (V1 - V2) + P3 × V3 + P4 × V4 is satisfied, where P1 is a pressure in a bubble accumulation chamber (520), V1 is an inner volume of the bubble accumulation chamber, V2 is a target bubble volume after bubble removal from the bubble accumulation chamber, P3 is an atmospheric pressure, V3 is a volume of a gas flowing into a depressurization chamber (760) from an atmosphere during a bubble removal operation, P4 is a pressure in the depressurization chamber before the bubble removal operation, and V4 is an inner volume of the depressurization chamber.