Liquid Ejection Head With Gas-Permeable Bubble Discharge
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Solution Overview
Problem
Bubbles entering liquid ejection heads during tank replacement or head replacement can lead to insufficient liquid ejection pressure and potential leakage due to expansion, affecting the stability and performance of liquid ejection apparatuses.
Innovation Solution
A liquid ejection head design featuring a depressurization chamber with a gas permeable film, a first opening located lower than a second opening, and depressurization units that communicate with the outside, allowing for efficient bubble discharge through controlled depressurization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a sub tank greatly bulges from the ejection unit to route tubes, then gas discharge and ink tubes can be connected, but the head unit size increases
Solution Approach 1:
The patent repositions the sub tank from a lateral/bulging configuration to a vertical arrangement beneath the ejection unit. This dimensional change allows tube routing to occur in the vertical space rather than requiring horizontal expansion, thereby maintaining tube connection capability while significantly reducing the head unit's footprint in the scanning direction
Solution Approach 2:
Instead of having the sub tank protrude outward from the ejection unit as in conventional designs, the patent inverts the arrangement by placing the sub tank underneath the ejection unit. This inverted configuration reverses the spatial relationship, allowing tubes to be routed upward from the sub tank to the ejection unit, achieving the same functional connection with a more compact overall structure
2Reliability
If bubbles enter the liquid ejection head, then liquid ejection pressure becomes insufficient, but the patent provides no effective bubble discharge mechanism
Solution Approach 1:
The patent implements a self-service bubble discharge mechanism where the system automatically removes bubbles without requiring external intervention or complex additional components. The depression chamber with its gas-permeable partition and communication opening creates a self-actuating system that passively draws bubbles from the liquid reservoir chamber through pressure differential, maintaining reliable liquid ejection pressure through an elegant self-regulating mechanism
Solution Approach 2:
The patent introduces a depression chamber as an intermediary component between the liquid reservoir chamber and the external environment. This intermediate chamber, equipped with a gas-permeable partition, serves as a mediator that facilitates bubble removal by providing a transition zone where bubbles can be separated from the liquid and discharged, thereby protecting the liquid ejection system from bubble-related pressure issues
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 removes bubbles, maintaining stable liquid ejection pressure and preventing leakage, thereby enhancing the reliability and performance of the liquid ejection apparatus.
Implementation Method 1
a gas permeable film therebetween and configured such that an inside of the depressurization chamber is depressurizable
Implementation Method 2
the pressure inside the gas collection hollow portion is set to be lower than the pressure inside the filter chamber to cause a gas in the filter chamber to permeate through the permeable partition by means of the pressure difference
Implementation Method 3
a depressurization chamber adjoining the liquid reservoir chamber with a gas permeable film therebetween and configured such that an inside of the depressurization chamber is depressurizable
Implementation Method 4
a first opening through which the liquid reservoir chamber communicates with an outside; and a second opening through which the depressurization chamber communicates with an outside, wherein the first opening is located on a lower side in a vertical direction relative to the second opening
Data Source
AI summary
An object is to downsize a liquid ejection head and a liquid ejection apparatus. To this end, a liquid ejection head includes: an ejection port for ejecting the liquid; a pressure chamber provided with an energy generation element which generates an energy for ejecting the liquid from the ejection port; a liquid reservoir chamber which fluidly communicates with one end of the pressure chamber and holds the liquid to be supplied to the pressure chamber; a depressurization chamber adjoining the liquid reservoir chamber with a gas permeable film therebetween and configured such that an inside of the depressurization chamber is depressurizable; a first opening through which the liquid reservoir chamber communicates with an outside; and a second opening through which the depressurization chamber communicates with an outside. The first opening is located on a lower side in a vertical direction relative to the second opening.