Liquid Ejecting Head Freeze Prevention via Evaporation Micro-Vibration

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Liquid ejecting apparatuses face damage due to freeze of liquids in the flow path, leading to component breakage and poor ejection performance due to air bubbles when the path is refilled, as existing solutions require complex mechanisms and increase the apparatus size.

Innovation Solution

A method involving an evaporation micro-vibration operation is performed by detecting power-off operations and using drive elements to generate pressure fluctuations that evaporate solvents in the ink, reducing the risk of freeze and preventing air bubbles by thickening the ink before power shutdown, thus minimizing component damage and maintaining ejection performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the liquid is discharged from the pressure chamber using a pump to prevent freeze damage, then the reliability is improved, but the device complexity increases

Engineering Contradiction:

Improvefreeze damage preventionVSAvoidapparatus structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The liquid ejecting head uses its own drive elements to generate pressure fluctuations that move and discharge liquid from the pressure chamber, eliminating the need for external pumps or complex discharge mechanisms. The system serves itself by utilizing existing components for dual purposes (ejection and freeze prevention).

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The drive elements are used for both liquid ejection during normal operation and liquid discharge during power-off periods to prevent freeze damage. This multi-functional use of existing components avoids adding separate discharge mechanisms, reducing overall device complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If the liquid flow path is refilled with liquid after freeze, then the reliability is improved, but air bubbles mix with the liquid causing poor ejection performance

Engineering Contradiction:

Improveliquid flow path integrityVSAvoidejection performance

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The system performs preliminary discharge of liquid from the pressure chamber before power-off, and the liquid flow path is sealed before air can enter. When power is restored, the system is ready for immediate operation without requiring refilling operations that would introduce air bubbles.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent introduces a capping mechanism that seals the nozzle as an intermediary between the liquid ejection system and the external environment. This cap prevents air from entering the liquid flow path during power-off periods and refilling operations, eliminating air bubble contamination.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Device complexity

If the liquid is kept in the pressure chamber during power-off, then the device complexity is reduced, but the liquid freezes causing component breakage

Engineering Contradiction:

Improveapparatus structureVSAvoidcomponent integrity

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The system performs preliminary discharge of liquid from the pressure chamber before power-off operation. This preliminary action removes the freeze-prone liquid from vulnerable components, preventing freeze damage without requiring complex heating or insulation systems.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces complex thermal protection systems (heating elements, insulation) with a mechanical discharge system that uses pressure fluctuations to remove liquid from the pressure chamber. This substitution simplifies the overall system while effectively preventing freeze damage.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 method effectively reduces damage from liquid freeze by evaporating solvents in the ink, preventing air bubbles and maintaining ejection performance without increasing apparatus complexity or size, ensuring reliable operation in low-temperature environments.

Implementation Method 1

driving the drive elements to the extent the liquid is not ejected from the nozzles... generate pressure fluctuations that evaporate solvents in the ink

Methodology Applied

Scientific EffectEvaporation: Evaporation

Implementation Method 2

The liquid ejecting head generates pressure fluctuations in the liquid in the pressure chamber by driving an actuator such as a piezoelectric element and ejects the liquid from the nozzle as droplets by the pressure fluctuations

Methodology Applied

Scientific EffectPressure fluctuations: Pressure Gradient

Data Source

PatentUS10913267B2Method of controlling liquid ejecting apparatus and liquid ejecting apparatus

Publication Date: 2021.02.09 SEIKO EPSON CORP

AI summary

A method of controlling a liquid ejecting apparatus that includes a liquid ejecting head having nozzles configured to eject a liquid, pressure chambers communicating with the nozzles, and drive elements configured to change the volume in the pressure chambers, and a drive-waveform generating circuit configured to generate a drive waveform for driving the drive elements to vibrate the liquid in the nozzles is provided. The method includes detecting a power-off operation for issuing an instruction for turning off an electric power of the liquid ejecting apparatus and vibrating the liquid by driving piezoelectric elements by the drive waveform in response to detecting the power-off operation by the detecting.