Multicolor Thermal Recording Material with Composite Fine Particles

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing multicolor thermal recording materials can only produce up to three colors, limiting their versatility and requiring additional layers and dye precursors with specific melting points, which increases production costs and restricts material selectivity.

Innovation Solution

A multicolor thermal recording material with three thermal color-developing layers, each containing a different dye precursor and color-developing compound, where the second and third layers comprise composite fine particles formed by emulsifying a polyvalent isocyanate compound with the dye precursors, allowing for the development of yellow, magenta, or cyan colors, and enabling the production of at least four colors by controlling the heating temperature and pulse width from a thermal head.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple thermal color-developing layers are provided to achieve multicolor printing, then color variety is improved, but production complexity and cost increase due to additional intermediate layers and coating processes

Engineering Contradiction:
Improvecolor varietyVSAvoidproduction complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges the second and third thermal color-developing layers by removing the intermediate layer between them, allowing direct contact and potential interaction between the layers while maintaining distinct color development capabilities. This reduces production complexity while preserving multicolor functionality.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent segments the color development function by using different dye precursors with specific melting points in each layer, allowing independent control of color development temperatures. The first layer uses a dye precursor with a lower melting point for lower temperature development, while the second and third layers use dye precursors with higher melting points for higher temperature development.

Inventive Principle:
Principle #1Segmentation

2Manufacturing precision

If dye precursors with specific melting points are used to control color development temperature, then color development precision is improved, but material selectivity is restricted

Engineering Contradiction:
Improvecolor development temperature controlVSAvoidmaterial selectivity
Core Design Contradiction:
Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The patent changes the melting point parameter of dye precursors to control color development temperature. By selecting dye precursors with appropriately different melting points, the patent achieves temperature-controlled color development while maintaining flexibility in material selection.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite fine particles containing both the dye precursor and color-developing compound, creating a new material system that integrates multiple functions. This composite approach allows for broader material selectivity while maintaining precise temperature control through the inherent properties of the composite materials.

Inventive Principle:
Principle #40Composite materials

3Manufacturing precision

If intermediate layers are added between thermal color-developing layers to control temperature transmission, then temperature control is improved, but production time and cost increase

Engineering Contradiction:
Improvetemperature controlVSAvoidproduction efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent extracts and removes the intermediate layer between the second and third thermal color-developing layers, eliminating the additional coating and drying processes associated with intermediate layers. Temperature control is achieved instead through the inherent thermal properties of the dye precursors and the lamination structure itself.

Inventive Principle:
Principle #2Taking out (Extraction)

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 multicolor printing in four colors (yellow, blue, red, and black) with improved material selectivity and reduced production complexity, allowing for vivid color mixing and separation without the need for an intermediate layer between the second and third color-developing layers.

Implementation Method 1

the second dye precursor-containing particle component contained in the second thermal color-developing layer comprises composite fine particles containing the second dye precursor and a polymeric compound, and the third dye precursor-containing particle component contained in the third thermal color-developing layer comprises composite fine particles containing the third dye precursor and a polymeric compound

Methodology Applied
Scientific EffectEmulsion: Emulsion

Implementation Method 2

a multicolor thermal recording material capable of developing different colors depending on differences in the conditions of applying heat from a thermal head

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 3

a coloring reaction of a dye precursor and a color developer that develops the color of the dye precursor upon contact with the dye precursor under heating

Methodology Applied
Scientific EffectChemical reaction: Chemical Bonding

Data Source

PatentEP2944477B1Multicolor thermal recording material, and method for color formation of said multicolor thermal recording material
Publication Date: 2019.04.10 OJI HLDG CORP
  • EP2944477B1 patent drawingFigure 1~2A2
  • EP2944477B1 patent drawingFigure 3~4C2
  • EP2944477B1 patent drawingFigure 5~5D2

AI summary

The present invention provides a multicolor thermal recording material that allows multicolor printing in at least four colors, depending on differences in the conditions of applying heat from a thermal head, and that is inexpensive and has excellent material selectivity, as well as providing a method for developing color of the multicolor thermal recording material. The multicolor thermal recording material comprises (1) a support, and in order from a side close to the support, (2) a first thermal color-developing layer containing a first dye precursor and a color-developing compound reactive with the first dye precursor under heating to develop the color of the first dye precursor, (3) an intermediate layer, (4) a second thermal color-developing layer containing a particle component containing a second dye precursor, and a color-developing compound reactive with the second dye precursor under heating to develop the color of the second dye precursor, and (5) a third thermal color-developing layer containing a particle component containing a third dye precursor, and a color-developing compound reactive with the third dye precursor under heating to develop the color of the third dye precursor; wherein the first, second, and third dye precursors are capable of developing mutually different colors; the second dye precursor-containing particle component contained in the second thermal color-developing layer comprises composite fine particles containing the second dye precursor and a polymeric compound; and the third dye precursor-containing particle component contained in the third thermal color-developing layer comprises composite fine particles containing the third dye precursor and a polymeric compound.