Liquid Ejecting Head Mist Recovery Recess Design

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Solution Overview

Problem

Existing liquid ejecting heads face reliability issues due to fine liquid droplets (mist) adhering to the ejection port and position sensors, causing clogging and inaccurate ejection, despite attempts to recover mist using airflow and suction ports at equal intervals from the print medium.

Innovation Solution

A liquid ejecting head design featuring a mist recovering mechanism with a recess between the mist recovering unit and the gas blowing unit, where the suction and blowing ports are positioned within the recess to create a vortex that effectively recovers mist without clogging the ejection port, using a combination of suction and gas blowing to prevent mist from flowing downstream.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a suction port is arranged at an equal interval from the print medium to recover mist, then the structure is simple, but the mist cannot be sufficiently recovered and adheres to the ejection port

Engineering Contradiction:
Improvestructure simplicityVSAvoidejection reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The mist recovering mechanism is divided into multiple functional components: a blowing port for generating airflow, a suction port for extracting mist, and a recess structure that positions these components at different locations relative to the print medium. This segmentation allows the blowing and suction ports to be arranged optimally to recover diffused mist without requiring complex overall structure

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A recess structure is introduced as an intermediary element between the blowing/suction ports and the print medium. This recess allows the ports to be positioned at unequal intervals from the medium, creating an airflow path that effectively captures diffused mist. The recess acts as a mediator that resolves the contradiction between structural simplicity and effective mist recovery

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If the suction port is positioned to recover diffused mist, then mist recovery efficiency improves, but the positioning becomes complex

Engineering Contradiction:
Improvemist recovery efficiencyVSAvoidpositioning complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The recess structure introduces a vertical dimension to the positioning of the blowing and suction ports. Instead of only horizontal positioning relative to the print medium, the recess creates a multi-dimensional arrangement where ports can be positioned at different heights and distances. This dimensional change enables effective mist recovery without requiring complex horizontal positioning adjustments

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Reliability

If gas blowing is applied to prevent mist downstream flow, then mist recovery stabilizes, but energy consumption increases

Engineering Contradiction:
Improvemist recovery stabilityVSAvoidenergy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The mechanism uses pneumatic principles by introducing gas through the blowing port to create an airflow that prevents mist from flowing downstream. This pneumatic approach provides stable mist recovery by using gas dynamics to control mist movement. The energy consumption is managed by optimizing the gas flow rate to the minimum necessary for effective mist prevention

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

The solution stabilizes mist recovery, preventing ejection port closure and maintaining ejection reliability by forming a vortex within the recess, ensuring efficient mist removal without disrupting the airflow for main droplet ejection.

Implementation Method 1

a recess is formed between a mist recovering unit and a gas blowing unit in a mist recovering mechanism, wherein a blowing port of the gas blowing unit is formed inside the recess... blowing gas to form a vortex

Methodology Applied
Scientific EffectVortex: Vortex Ring

Implementation Method 2

a suction port, through which the airflow is sucked, and a blowing port that can blow gas are formed inside the recess... the airflow under a negative pressure is sucked

Methodology Applied
Scientific EffectSuction: Suction

Data Source

PatentEP3081382B1Liquid ejecting apparatus and liquid ejecting head
Publication Date: 2018.10.10 CANON KK
  • EP3081382B1 patent drawingFigure 1A~1B
  • EP3081382B1 patent drawingFigure 2A~2C
  • EP3081382B1 patent drawingFigure 3

AI summary

There is provided a liquid ejecting apparatus and a liquid ejecting head (5) in which mist does not close an ejection port (7) so as to prevent any degradation of the reliability of ejection. In view of this, a ceiling surface (40) is formed between a mist recovering unit (2) and a gas blowing unit in a mist recovering mechanism, thus forming a recess. Inside of the recess are formed a suction port (20) of the mist recovering unit (2) and a gas blowing port (30) of the gas blowing unit.