Tablet Inkjet Ink Composition for Fixed Print Without Nozzle Drying

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Solution Overview

Problem

Existing inkjet inks for tablets suffer from poor ink fixedness (transfer durability) while maintaining printing stability, leading to external defects and reduced productivity due to unintended ink transfer between tablets.

Innovation Solution

An inkjet ink comprising an edible dye, a liquid adhesive (such as polyethylene glycol), and a solvent mixture of water and ethanol, with specific compounding ratios to enhance ink fixedness and stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the amount of drying solvent in the ink is increased to improve ink drying properties and fixedness, then ink transfer durability is improved, but nozzle liquid surface drying is promoted and printing stability deteriorates

Engineering Contradiction:
Improveink fixednessVSAvoidprinting stability
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent changes the physical state parameter of the adhesive from solid/gel to liquid form. This parameter change allows the adhesive to remain dissolved in the ink solvent system without precipitating or forming gel structures that would cause nozzle clogging, while still providing the necessary adhesion function to improve ink fixedness.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies different functional properties to different components: the liquid adhesive provides localized adhesion enhancement at the ink-tablet interface, while the solvent system (water and ethanol) maintains overall ink fluidity and printability. This local quality differentiation resolves the contradiction between fixedness and printing stability.

Inventive Principle:
Principle #3Local quality

2Reliability

If a solid or gel-type adhesive is used to improve ink fixedness, then ink transfer durability is improved, but printing quality such as intermittent resumability deteriorates

Engineering Contradiction:
Improveink fixednessVSAvoidprinting quality
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent changes the physical state parameter of the adhesive from solid/gel to liquid form. This parameter change allows the adhesive to remain dissolved in the ink solvent system without precipitating or forming gel structures that would cause nozzle clogging, while still providing the necessary adhesion function to improve ink fixedness.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The liquid adhesive acts as an intermediary substance that bridges the ink and tablet surface. It provides adhesion functionality without the negative effects of solid/gel adhesives, mediating between the requirement for fixedness and the requirement for printing quality by remaining in a fluid state that is compatible with inkjet deposition.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

The inkjet ink improves ink fixedness and maintains excellent printing stability, preventing unintended transfer and enhancing productivity by ensuring proper adhesion and visibility of the printing image.

Implementation Method 1

an inkjet ink includes an edible dye, an adhesive, and water and ethanol as a solvent, and includes only a liquid adhesive as the adhesive

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 2

water and ethanol as a solvent

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentEP4647473A1Inkjet ink for tablet and tablet printed matter
Publication Date: 2025.11.12 TOPPAN HOLDINGS INC
  • EP4647473A1 patent drawingFigure 1~3
  • EP4647473A1 patent drawingFigure 4
  • EP4647473A1 patent drawing

AI summary

An object of the present invention is to provide an inkjet ink in which fixedness (transfer durability) of the ink is improved while maintaining excellent printing stability, and a tablet printed matter including a printing portion printed with the inkjet ink. The inkjet ink according to the present embodiment includes an edible dye, an adhesive, and water and ethanol as a solvent, and only a liquid adhesive as the adhesive.