Liquid Ejecting Head Moisture Absorbent Placement

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Solution Overview

Problem

Existing liquid ejecting heads face issues with moisture ingress into the driving element's accommodation space, leading to potential corrosion and changes in ejection characteristics due to pressure fluctuations caused by sealed environments, which are exacerbated by the number of driving elements used.

Innovation Solution

A liquid ejecting head design featuring a sealing body with a communication hole connecting the driving element's space to a vented case member, incorporating a moisture absorbent in the case member to absorb any entering moisture and suppress pressure fluctuations, while maintaining the hygroscopic capacity of the absorbent by positioning it closer to the communication hole than the vent.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the accommodation space of the driving element is sealed to protect from moisture, then moisture protection is improved, but pressure fluctuation occurs due to vibration propagation

Engineering Contradiction:

Improvemoisture protection of driving elementVSAvoidpressure fluctuation in accommodation space

Core Design Contradiction:

ReliabilityVSStress or pressure

Solution Approach 1:

A moisture absorbent is introduced as an intermediary substance in the communication path between the accommodation space and atmosphere. This mediator allows pressure equalization while capturing moisture that enters through the communication hole, thus resolving the contradiction between sealing for moisture protection and venting for pressure stabilization

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The space is divided into different functional zones: the accommodation space for driving elements, the adhesive escape space, and the communication space with atmosphere. Each zone has different properties - the accommodation space protects sensitive components, while the communication space with moisture absorbent handles pressure and moisture management locally

Inventive Principle:

Principle #3Local quality

2Reliability

If the atmosphere communication path is closed to block moisture, then moisture protection is improved, but ejection characteristic changes due to pressure fluctuation

Engineering Contradiction:

Improvemoisture protection of driving elementVSAvoidejection characteristic consistency

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The moisture absorbent acts as a mediator that allows the communication hole to remain open for pressure equalization while selectively removing moisture from the air that passes through, thus maintaining both moisture protection and ejection characteristic consistency

Inventive Principle:

Principle #24Intermediary (Mediator)

3Stress or pressure

If the accommodation space communicates with atmosphere, then pressure fluctuation is suppressed, but moisture enters the accommodation space

Engineering Contradiction:

Improvepressure stability in accommodation spaceVSAvoidmoisture ingress into accommodation space

Core Design Contradiction:

Stress or pressureVSObject-affected harmful factors

Solution Approach 1:

The moisture absorbent is placed in the communication path as an intermediary that allows free air flow for pressure equalization while selectively absorbing moisture molecules, thus enabling pressure stability without moisture ingress

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The moisture absorbent uses porous material structure to allow air molecules to pass through freely while trapping moisture molecules through capillary condensation and adsorption in the pores, enabling selective filtration

Inventive Principle:

Principle #31Porous materials

4Object-affected harmful factors

If moisture absorbent is placed in second space, then moisture is absorbed, but absorbent hygroscopic capacity decreases over time

Engineering Contradiction:

Improvemoisture absorption in second spaceVSAvoidhygroscopic capacity duration of absorbent

Core Design Contradiction:

Object-affected harmful factorsVSDuration of action of stationary object

Solution Approach 1:

The moisture absorbent is pre-positioned in the communication hole area where moisture first enters from atmosphere. This preliminary placement allows the absorbent to capture moisture at the source before it can saturate the entire second space, extending the effective duration of hygroscopic action

Inventive Principle:

Principle #10Preliminary action

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 effectively protects the driving element from moisture while minimizing pressure fluctuations, maintaining ejection characteristics and extending the absorbent's hygroscopic effectiveness by strategically placing the moisture absorbent to reduce moisture entry and enhance evaporation absorption.

Implementation Method 1

a moisture absorbent in the second space... the moisture is absorbed by the moisture absorbent in the second space

Methodology Applied

Scientific EffectHygroscopic absorption: Absorption (physical)

Implementation Method 2

the first space for accommodating the driving element communicates through a communication hole with the second space that communicates with atmosphere... the fluctuation of the pressure in the accommodation space caused by the vibration of the pressure chamber can be suppressed

Methodology Applied

Scientific EffectPressure equalization: Pressure Gradient

Data Source

PatentUS10654266B2Liquid ejecting head and liquid ejecting apparatus

Publication Date: 2020.05.19 SEIKO EPSON CORP

AI summary

A liquid ejecting head includes a plurality of driving elements that causes an ejection of a liquid from a nozzle by causing a fluctuation in a pressure, a sealing body that seals a first space for accommodating the plurality of driving elements, a case member that forms a second space for surrounding the sealing body, an atmosphere vent that is formed in the case member and through which the second space communicates with the air, a communication hole that is formed in the sealing body and through which the first space communicates with the second space, and a moisture absorbent disposed in the second space.