Thermoreversible Recording Medium Particle Size Control

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Solution Overview

Problem

Thermoreversible recording media experience varying coloring densities due to differences in particle diameters of leuco dye and reversible color developer, leading to reading errors and reduced throughput in conveyor line systems, especially in high-temperature environments where repeated image rewriting is necessary.

Innovation Solution

A thermoreversible recording medium with a support and a thermoreversible recording layer containing leuco dye and reversible color developer, where the average particle diameter of granules is 0.35 micrometers or smaller, and includes a photothermal converting material to maintain stable coloring density without changing irradiation energy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the average particle diameter of granules is reduced to 0.35 micrometers or smaller, then coloring density stability is improved, but manufacturing precision requirements increase

Engineering Contradiction:
Improvecoloring density stabilityVSAvoidparticle diameter control precision
Core Design Contradiction:
Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The patent applies parameter changes by optimizing the average particle diameter of granules to 0.35 micrometers or smaller, which fundamentally alters the physical state of the leuco dye and reversible color developer particles. This parameter change ensures uniform heating characteristics and consistent coloring density across multiple image recording cycles, resolving the technical contradiction between coloring density stability and manufacturing precision requirements.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent utilizes phase transitions of the photothermal converting material and the leuco dye-reversible color developer system. The photothermal converting material absorbs laser energy and transitions to a high-temperature state, which then transfers heat to the granules, causing them to melt and mix uniformly. This phase transition mechanism ensures consistent coloring density regardless of minor variations in particle diameter during manufacturing.

Inventive Principle:
Principle #36Phase transitions

2Device complexity

If irradiation energy is kept constant during repeated image recording, then system simplicity is improved, but coloring density consistency deteriorates

Engineering Contradiction:
Improvesystem simplicityVSAvoidcoloring density consistency
Core Design Contradiction:
Device complexityVSStability of the object's composition

Solution Approach 1:

The patent changes the physical parameters of the recording medium (granule size, composition ratios) rather than adjusting the irradiation energy during repeated operations. This approach maintains system simplicity while achieving coloring density consistency through optimized material properties that respond uniformly to constant irradiation energy across multiple recording cycles.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If larger particle diameters are used, then manufacturing ease is improved, but reading accuracy deteriorates due to coloring density variation

Engineering Contradiction:
Improvegranule production easeVSAvoidreading accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent optimizes the particle diameter parameter to 0.35 micrometers or smaller, which represents a significant refinement from conventional larger particles. This parameter change ensures that the granules heat uniformly under laser irradiation, producing consistent coloring density that maintains high reading accuracy while still being manufacturable through advanced particle production techniques.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3271189B1Thermoreversible recording medium, image processing device using the same, and conveyor line system
Publication Date: 2023.05.10 RICOH CO LTD
  • EP3271189B1 patent drawingFigure 1A~2A
  • EP3271189B1 patent drawingFigure 2B~4A
  • EP3271189B1 patent drawingFigure 4B~5

AI summary

To provide a thermoreversible recording medium including a support, and a thermoreversible recording layer, which is disposed on the support, and contains a leuco dye, and a reversible color developer, wherein an average particle diameter of granules in the thermoreversible recording layer is 0.35 micrometers or smaller.