Laser-Engraved Resin Refill Tube Marks Visible Through Ink

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Solution Overview

Problem

Existing writing implement refills with engraved marks on synthetic resin ink storage tubes face visibility issues when ink is present, as the marks can be obscured.

Innovation Solution

The writing implement refill features an ink storage tube made of synthetic resin with an engraved mark formed by foaming, carbonizing, or both, using a reactive additive that absorbs laser light to enhance visibility, and optionally includes a multilayer structure with the additive only in the inner layer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If physical engraving is performed on the surface of an ink storage tube made of synthetic resin, then an engraved mark is formed, but the engraved mark becomes difficult to see when ink is contained in the ink storage tube

Engineering Contradiction:

Improveengraved mark formationVSAvoidvisibility of engraved mark

Core Design Contradiction:

Manufacturing precisionVSLoss of information

Solution Approach 1:

The patent changes the physical and chemical parameters of the synthetic resin by blending a reactive additive that undergoes foaming or carbonization when exposed to laser light. This transforms the engraving process from simple mechanical removal to a chemical-physical reaction that creates visible marks through color change (carbonization to black/dark brown) or volume change (foaming to white/light-colored protrusions), ensuring the marks remain visible regardless of ink presence

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces traditional mechanical engraving methods with laser-based processing. The laser beam (optical energy) substitutes for mechanical tools, enabling precise control over the engraving depth and pattern while triggering chemical reactions in the reactive additive. This substitution allows for consistent mark formation that maintains visibility under varying ink conditions

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Loss of information

If a reactive additive is blended in the synthetic resin to enhance visibility through foaming or carbonization, then the engraved mark becomes more visible, but the complexity of the material composition increases

Engineering Contradiction:

Improvevisibility of engraved markVSAvoidmaterial composition complexity

Core Design Contradiction:

Loss of informationVSDevice complexity

Solution Approach 1:

The patent applies local quality by concentrating the reactive additive only in specific regions where engraving is required, rather than uniformly throughout the entire ink storage tube. The multilayer structure further refines this by placing the reactive additive only in inner layers, keeping the outermost layer free of additives to maintain surface quality and simplify the overall material system

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent creates a composite material system by combining synthetic resin with a reactive additive blend. This composite approach allows the material to exhibit both the structural properties of the base resin and the reactive properties of the additive, enabling laser-induced foaming or carbonization. The composite nature is optimized by controlling the additive content (0.01-10 mass%) and positioning it strategically in multilayer configurations

Inventive Principle:

Principle #40Composite materials

3Loss of information

If the engraved mark protrudes from the surface of the ink storage tube to improve visibility and durability, then the visibility and durability are enhanced, but the manufacturing complexity increases

Engineering Contradiction:

Improvevisibility and durability of engraved markVSAvoidmanufacturing process complexity

Core Design Contradiction:

Loss of informationVSEase of manufacture

Solution Approach 1:

The patent applies preliminary action by incorporating the reactive additive into the synthetic resin during the molding process, before the engraving step. This pre-preparation ensures that when laser engraving occurs, the additive is already in position and ready to react, forming protruding marks automatically during the engraving process itself, rather than requiring separate protrusion-forming steps

Inventive Principle:

Principle #10Preliminary 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

This configuration ensures that the engraved mark remains visible both when the ink is contained and when it is not, providing improved durability and visibility compared to mechanical engraving.

Implementation Method 1

When the reactive additive absorbs laser light to generate heat

Methodology Applied

Scientific EffectLaser light absorption: Absorption (EM radiation)

Implementation Method 2

the reactive additive absorbs laser light to generate heat

Methodology Applied

Scientific EffectLaser heating: Heating

Implementation Method 3

the synthetic resin is foamed, carbonized, or foamed and carbonized

Methodology Applied

Scientific EffectFoaming: Foam

Implementation Method 4

the synthetic resin is foamed, carbonized, or foamed and carbonized

Methodology Applied

Scientific EffectCarbonization: Pyrolysis

Data Source

PatentUS20250115072A1Writing implement refill and method of engraving writing implement refill

Publication Date: 2025.04.10 MITSUBISHI PENCIL CO LTD

AI summary

A writing implement refill includes: an ink storage tube made of a synthetic resin, an inside of the ink storage tube being visible; and an engraved mark, on a surface of the ink storage tube, formed by the synthetic resin being foamed or carbonized or both.