Capillary Bristle Fluid Delivery for Self-Sanitizing Toothbrushes

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Solution Overview

Problem

Existing personal care implements, such as toothbrushes, suffer from issues like fluid channel clogging, drying out, malfunctioning mechanisms, and bacterial harboring, while toothpaste formulations with hydrogen peroxide are maintained at suboptimal pH for whitening, and there is a need for self-sanitizing features.

Innovation Solution

An oral care implement with a capillary member that delivers fluid to bristle tufts via capillary action, allowing passive fluid delivery to bristle filaments, and includes methods for whitening teeth by mixing buffer solutions with toothpaste and sanitizing bristles between uses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional fluid delivery mechanisms are used in toothbrushes, then fluid can be delivered to bristles, but the mechanisms are prone to clogging, drying out, and malfunctioning

Engineering Contradiction:
Improvefluid delivery reliabilityVSAvoidmechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces mechanical fluid delivery mechanisms (pumps, valves, channels) with a passive capillary-based delivery system. The capillary member utilizes capillary action to transport fluid from the reservoir to the bristle tufts, eliminating mechanical moving parts that are prone to clogging and malfunction. This substitution of mechanical systems with a passive physical phenomenon-based system directly addresses the reliability issues while reducing complexity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The capillary member is formed from a porous material that enables fluid transport through capillary action. The porous structure allows fluid to be drawn through the material without requiring mechanical pumps or complex channels. This use of porous materials provides a reliable, maintenance-free fluid delivery path that is resistant to clogging while maintaining simplicity in the overall device structure.

Inventive Principle:
Principle #31Porous materials

2Duration of action of stationary object

If toothpaste with hydrogen peroxide is maintained at low pH, then shelf life is maximized, but tooth whitening effectiveness is reduced

Engineering Contradiction:
Improveshelf lifeVSAvoidwhitening effectiveness
Core Design Contradiction:
Duration of action of stationary objectVSReliability

Solution Approach 1:

The patent incorporates a buffer solution reservoir that is activated prior to use. The buffer solution is delivered to the bristle tufts and mixes with the toothpaste formulation, raising the pH before application to the teeth. This preliminary pH adjustment action allows the hydrogen peroxide to maintain its stability during storage (low pH) while being activated to optimal pH levels just before use, ensuring both shelf life and whitening effectiveness.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes the pH parameter of the toothpaste formulation dynamically. The buffer solution reservoir allows the pH to be adjusted from the stable low pH during storage to an optimal higher pH before application. This parameter change is achieved through the mixing of buffer solution with the toothpaste in the bristle tufts, enabling the system to maintain different pH values at different stages (storage vs. application) to optimize both shelf life and effectiveness.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If toothbrushes are used continuously, then cleaning function is maintained, but bacteria accumulate on bristles

Engineering Contradiction:
Improvecleaning functionVSAvoidbacterial accumulation
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent implements a self-sanitizing feature where the buffer solution reservoir automatically delivers sanitizing fluid to the bristle tufts between uses. This self-service mechanism eliminates the need for manual cleaning or replacement, as the toothbrush cleans itself by utilizing the capillary delivery system to apply sanitizing agents to the bristles, thereby maintaining hygiene without user intervention.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent enables continuous useful action by maintaining the cleaning and sanitizing functions throughout the toothbrush's usage cycle. The buffer solution reservoir continuously provides sanitizing fluid through capillary action, ensuring that the bristles remain sanitized between brushing sessions. This continuous action prevents bacterial accumulation while maintaining the cleaning function, eliminating the need for periodic manual cleaning or replacement.

Inventive Principle:
Principle #20Continuity of useful 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

Enables effective fluid delivery without mechanical aids, enhances tooth whitening by adjusting pH, and passively sanitizes bristles, addressing clogging, drying, and bacterial issues.

Implementation Method 1

the at least one capillary member is configured to deliver the first fluid from the reservoir to the bottom end of the first bristle tuft via capillary action

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Implementation Method 2

the first bristle tuft is configured so that the first fluid flows axially along the first bristle tuft through spaces between the bristle filaments of the first bristle tuft from the bottom end of the first bristle tuft toward a distal end of the first bristle tuft via capillary action

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Data Source

PatentEP3863469B1Fluid dispensing oral care implement
Publication Date: 2026.03.18 COLGATE PALMOLIVE CO
  • EP3863469B1 patent drawingFigure 1~2
  • EP3863469B1 patent drawingFigure 3
  • EP3863469B1 patent drawingFigure 4A

AI summary

A personal care implement that dispenses a fluid to cleaning elements during a hygiene activity. The personal care implement may include a handle, a head, and a reservoir containing a fluid in one of the handle and the head. A plurality of bristle tufts may extend from the head along an axis. Each of the bristle tufts may include a plurality of bristle filaments that are arranged in the bristle tuft so that spaces exist within the bristle tuft. The personal care implement may also include a capillary member that is fluidly coupled to both the first fluid and to one of the bristle tufts. The fluid may flow by capillary action from the reservoir to a bottom end of the one of the bristle tufts and then upwardly along the bristle tuft within the spaces between the bristle filaments.