Hair Dye Applicator Geometry for Smooth Container Withdrawal

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Solution Overview

Problem

The applicator in existing hair dye containers tends to get caught in the vicinity of the container opening when pulled out, hindering smooth operation, especially when a scraper or sealing member is present to retain the application liquid.

Innovation Solution

The hair dye container design includes a grip serving as a cap with a rod and applicator, where the step perpendicular to the axis at the boundary of the rod and applicator is less than 1 mm, and features a cylindrical scraper to adjust liquid retention, along with comb teeth aligned straight and an inclined rod portion to enhance operability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the applicator is attached in a bent state or curved along the longitudinal direction to fit the container, then the applicator can be stored within the container body, but the applicator gets caught in the vicinity of the opening when pulled out

Engineering Contradiction:
Improveapplicator storage space utilizationVSAvoidapplicator removal smoothness
Core Design Contradiction:
Volume of moving objectVSEase of operation

Solution Approach 1:

The patent changes the geometric parameter of the rod-applicator boundary by reducing the step height to less than 1 mm. This parameter modification allows the applicator to be stored effectively while eliminating the catching problem during removal, as the minimal step provides sufficient clearance for smooth extraction.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If a scraper or sealing member is disposed at the opening to retain application liquid, then liquid retention is improved, but the applicator is more likely to get caught when pulled out

Engineering Contradiction:
Improveapplication liquid retentionVSAvoidapplicator removal smoothness
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent modifies the dimensional parameter of the rod-applicator interface by reducing the step height to less than 1 mm. This creates sufficient clearance between the applicator and the scraper/sealing member at the opening, allowing both effective liquid retention by the scraper and smooth applicator removal without catching.

Inventive Principle:
Principle #35Parameter changes

3Shape

If the applicator is formed with a bent state or curved shape, then the applicator can accommodate within the container body, but operability is hindered due to catching at the opening

Engineering Contradiction:
Improveapplicator configuration for storageVSAvoidapplicator removal operation
Core Design Contradiction:
ShapeVSEase of operation

Solution Approach 1:

The patent changes the geometric parameter at the rod-applicator boundary by reducing the step height to less than 1 mm. This allows the applicator to maintain its bent or curved configuration for proper storage while ensuring smooth removal by providing adequate clearance at the critical boundary interface.

Inventive Principle:
Principle #35Parameter changes

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 design prevents the applicator from getting caught, ensuring smooth operation and effective liquid application, with improved usability and reduced liquid spillage.

Implementation Method 1

the application liquid retained on the applicator by capillary action can be applied to such as eyelashes

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Data Source

PatentEP4702872A1Hair dyeing container
Publication Date: 2026.03.04 MITSUBISHI PENCIL CO LTD
  • EP4702872A1 patent drawingFigure 1(A)~1(C)
  • EP4702872A1 patent drawingFigure 2
  • EP4702872A1 patent drawingFigure 3(A)~3(D)

AI summary

Provided is a hair dyeing container which is improved in operability by solving the problem of an applicator body being caught in the vicinity of an opening of the container when the applicator body is pulled out of the container body. This hair dyeing container comprises: a container body 1 in which an application liquid is stored; and a grip 2 for an applicator body 4 for the application liquid, the grip 2 being detachably attached to an opening part 1a of the container body and serving as a cap for the container body, the applicator body 4 being disposed at a shaft tip-end via the shaft 3. A step h2 in a direction orthogonal to the axis of the shaft at a boundary between the shaft and the applicator body is set to less than 1 mm.