Aqueous Ballpoint Pen Ink Composition for Smooth Writing and Tip Wear

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Solution Overview

Problem

Existing aqueous ink compositions for ballpoint pens using pigment-encapsulating microcapsules cause deterioration in smooth writing and wear of the tip socket when using colored resin particles.

Innovation Solution

An ink composition for aqueous ballpoint pens containing colored resin particles encapsulating a pigment and non-colored resin particles, with specific ratios and particle sizes, to enhance smooth writing and prevent tip socket wear.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If colored resin particles encapsulating a pigment are used in aqueous ballpoint pen ink, then color strength and pigment loading are improved, but smooth writing deteriorates and tip socket wear increases

Engineering Contradiction:
Improvepigment loadingVSAvoidsmooth writing
Core Design Contradiction:
Quantity of substanceVSEase of operation

Solution Approach 1:

The patent introduces non-colored resin particles as intermediary components that do not contain pigment. These particles act as mediators between the colored resin particles and the tip socket, reducing direct contact and friction between pigment-containing particles and the tip socket surface, thereby maintaining smooth writing while preserving color strength

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The ink composition creates a composite particle system combining colored resin particles (for color strength) with non-colored resin particles (for smooth writing). This composite approach allows the ink to simultaneously achieve high pigment loading and smooth writing performance by leveraging the complementary properties of both particle types

Inventive Principle:
Principle #40Composite materials

2Quantity of substance

If colored resin particles encapsulating a pigment are used in aqueous ballpoint pen ink, then color strength and pigment loading are improved, but tip socket wear increases

Engineering Contradiction:
Improvepigment loadingVSAvoidtip socket wear
Core Design Contradiction:
Quantity of substanceVSObject-generated harmful factors

Solution Approach 1:

Non-colored resin particles serve as protective intermediaries that reduce direct interaction between pigment-containing colored resin particles and the tip socket. This intermediary layer minimizes mechanical wear and damage to the tip socket while maintaining the pigment loading benefits

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent converts the potential harm of pigment particles causing wear into a benefit by using non-colored resin particles to absorb the mechanical stress and friction, thereby protecting the tip socket while allowing the pigment to maintain its color strength function

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Data Source

PatentUS12473445B2Ink composition for aqueous ballpoint pens
Publication Date: 2025.11.18 MITSUBISHI PENCIL CO LTD

AI summary

An aqueous ink composition suitable for ballpoint pens may achieve excellent smooth writing without causing deterioration of the smooth writing and wear of a tip socket while colored resin particles encapsulating a pigment are used. An embodiment of such ink compositions is an aqueous ink composition suitable for ballpoint pens containing at least colored resin particles (A) encapsulating a pigment (a) and non-colored resin particles (B) containing no pigment.