Mist Removing Head Vortex Airflow for Print Head Smudge Reduction

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Solution Overview

Problem

Conventional liquid ejecting apparatuses face challenges in efficiently removing mist generated between the print head and the print medium, leading to reduced ejection performance, image degradation, and smudges, as existing methods either misregister droplet landing positions or fail to adequately remove mist, requiring trial and error for optimization.

Innovation Solution

A liquid ejecting apparatus with a mist removing head featuring a suction hole and a blowing hole, where air is simultaneously sucked and blown to create a vortex that efficiently removes mist without disturbing the landing position of main droplets, utilizing specific airflow rate and distance conditions to optimize mist removal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If air is sucked through a suction hole to remove mist, then mist removal is achieved, but the landing position of main droplets is misregistered due to airflow influence

Engineering Contradiction:
Improvemist adhesionVSAvoiddroplet landing position
Core Design Contradiction:
Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The mist removal function is segmented from the print head ejection system by introducing a separate mist removing head with suction and blowing holes positioned downstream. This spatial segmentation allows mist removal operations to be performed in a region separate from the droplet ejection zone, eliminating airflow interference with droplet landing positions while maintaining effective mist removal capability

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A mist removing head acts as an intermediary device between the print head and the print medium. This intermediary component performs the mist removal function through suction and blowing holes, mediating the airflow to remove mist without allowing the suction airflow to directly interfere with the droplet ejection process, thus resolving the contradiction between mist removal and positioning accuracy

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If air is blown and sucked in large quantities to remove mist, then mist removal efficiency is improved, but droplet landing position is misregistered due to strong airflow

Engineering Contradiction:
Improvemist removal efficiencyVSAvoiddroplet landing position
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The airflow rates for suction and blowing are made dynamically adjustable within specific ranges (suction: 0.5-5 L/min, blowing: 0.5-3 L/min) rather than fixed. This dynamic control allows optimization of mist removal efficiency while maintaining airflow levels that do not disrupt droplet landing, resolving the contradiction between removal efficiency and positioning precision

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the parameters of airflow rate and positioning distance to optimal values. By setting suction airflow rate between 0.5-5 L/min and blowing airflow rate between 0.5-3 L/min, and positioning the mist removing head 5-20mm downstream, the system achieves both high mist removal efficiency and accurate droplet landing, resolving the contradiction between these two requirements

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If air is sucked or blown in small quantities, then droplet landing position accuracy is maintained, but mist cannot be sufficiently removed

Engineering Contradiction:
Improvedroplet landing positionVSAvoidmist removal adequacy
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The invention merges suction and blowing operations into a coordinated system where both functions work together in the mist removing head. The suction hole removes mist while the blowing hole provides counter-flow to prevent airflow disruption to droplets, achieving both adequate mist removal and positioning accuracy through combined action

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The suction and blowing operations are performed at partial levels (not maximum strength) within optimized ranges. By using moderate airflow rates (suction: 0.5-5 L/min, blowing: 0.5-3 L/min) rather than excessive forces, the system achieves sufficient mist removal without creating strong airflow that would disrupt droplet landing, resolving the contradiction between removal adequacy and positioning precision

Inventive Principle:
Principle #16Partial or excessive 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

The apparatus effectively reduces smudges on the print head and medium by efficiently removing mist, maintaining image quality and ejection performance through controlled airflow management.

Implementation Method 1

air is simultaneously sucked and blown to create a vortex that efficiently removes mist

Methodology Applied
Scientific EffectVortex: Vortex Ring

Data Source

PatentEP3072695B1Liquid ejecting apparatus
Publication Date: 2020.01.15 CANON KK
  • EP3072695B1 patent drawingFigure 1A~1B
  • EP3072695B1 patent drawingFigure 2
  • EP3072695B1 patent drawingFigure 3

AI summary

A suction hole (7) sucks air existing in a region S together with mist (12) is formed downstream of a liquid ejecting unit (11), as viewed from the liquid ejecting unit, in a movement direction (i.e., a direction E) of a print medium (P) in the case of relative movement between the liquid ejecting unit and the print medium. Moreover, a blowing hole blows air toward the print medium so as to generate a vortex (V) of gas downstream of the suction hole is formed downstream of the suction hole (7) in the movement direction. Here, a relationship expressed by the following expression is satisfied: γ≥h/3 where y represents a maximum vortex core radius (mm) of the vortex in a direction perpendicular to the print medium and h represents a distance (mm) between a blowing hole and the print medium.